THE BOTANICAL GAZETTE EDITORS: JOHN MERLE COULTER anp CHARLES REID BARNES VOLUME XLVI JULY-DECEMBER, 1908 WITH THIRTY-THREE PLATES AND SIXTY-EIGHT FIGURES 3 CHICAGO THE UNIVERSITY OF CHICAGO PRESS 1908 BOTANICAL GAZETTE TABLE OF CONTENTS A study of reduction in Oenothera rubrinervis. Con- tributions from the Hull Botanical oS CXI (with plates I-III) - - Reginald Ruggles Gates Studies in Araceae (with plates IV-V) - - - James Ellis Gow The embryo sac and embryo of Gnetum : Contributions from the Hull Botanical Labora- tory CXII (with plate VII) Biases John M. Coulter Floral succession in the prairie-grass Ssnihiision in southeastern South Dakota. | Contributions from the Hull ee ti ai CXiIr (with three figures) - - LeRoy Harris Harvey Undescribed plants from Gannenale and other Cen- tral American republics. XXX - -'John Donnell Smith A method for the quantitative ieceeatoniion of tran- spiration in plants (with one figure) - Geo. F. Freeman oe: toxic property of bog water and bog soil wth : Alfred Dachnowski The andaais cone and ee sananiptigts of Podo- carpus. Contributions from the Hull Botanical Laboratory CXIV sos nine or and wer VII and I L. Lancelot Burlingame Sisyrinchium: snabiaical ee of North American species (with plates X, XI, ge Theo. Holm A new respiration calorimeter - - George J. Peirce The seedling of Ceratozamia. Contributions: from the Hull Botanical Laboratory nes (with two figures and plates XII—XVI) Helen A. Dorety Are there foliar gaps in the Lyeopsida? vith plates XVII and XVIII) Edward C. Jeffrey Effect of illuminating gas ‘mod pees upon en carations. Contributions from the Hull Botanical Laboratory CXVI (with four figures) William Crocker and Lee I. Knight Floral succession in the prairie-grass formation of southeastern South Dakota. Contributions from the Hull Botanical egmeames! CXVII (with four figures) - LeRoy Harris Harvey Observations on Poppers olds toa and some of its allies from Europe and North America (with five figures and plate XIX) - - ~- George F. Atkinson The morphology of Phyllocladus alpinus. Contribu- tions from the Hull Botanical esanigpend CXVIII (with plates XX—XXIT) - N. Johanna Kildahl v PAGE vi CONTENTS [VOLUME XLVI Notes on numerical variation in the daisy = J ee Eaeforile The vascular anatomy of the seedling of Dioon edule. Contributions from the Hull Botanical Labora- tory CXIX (with plates XXITI-XXIX) - Reinhardt Thiessen Bryological papers: II. The origin of the nigule of Marchantia. Contributions from the Hull Botanical eee CXX (with fourteen fi ) - - Charles R. Barnes and W.J.G. Land Emergence of lateral roots (with three figures) - - Raymond H. Pond Studies in the Gramineae: IX. The Gramineae of the alpine region of the Rocky Mountains in Colorado (with five figures and plate XXX) Theo. Holm The nature of the embryo sac of Peperomia (with plates XAMI-XAXUD) +. +. <3 ee gy . Brown BRIEFER ARTICLES— The occurrence and rate of ee stream- ing in greenhouse plants - Grace L. Bushee On plasmolysis . - W. J. V. Osterhout The flowers of Washingtonia (with hive feces: S. B. Parish The number and size of the stomata - - - Sophia H. Eckerson The absorptive pve of a cultivated soil (with three figures) - Joseph a and Charles Heller A parasitic alga, Rocky Set ota Lagerheim, in North Ameri - George F. Atkinson Note on balanced solutions - Oscar Loew Formation of adventitious roots in the ealicils tree (with two figures) - O. M. Ball New —— — of Crataegus (vith two - Francis Ramaley Sexual conse in Fepautl - co A. F. Blakeslee A new characteristic of Engelmann ae - E. R. Hodson A new poisonous mushroom - - George F. Atkinson Affinities of Phyllocladus. Contcibatioans from the Hull Botanical Laboratory CXXI - -N. Johanna Kildahl Note on the pollen of oe - Robert Boyd Thomson CurRENT LITERATURE - - For titles of books reviewed see eae adie author’s name and Reviews Papers noticed in “Notes for Students” are indexed under author’s name and oo DATES OF PUBL PUBLICATION 349 56, 148, 230, 305, 387, 467 No. 1, July 23; No. 2, August 22; No. 3, September 22; No. 4, October 175 bs : No. 5, November 16; No. 6, Decenibes ERRATA P. 43, footnote 2, for KAarsTEN, H., read Karsten, G. P. 52, Tradescantia zebrina optimum, for .g90 read .966. P. 88, in table under Mean chresard, for 14.7% read 14.1%. P. 109, line 2 from top, omit hyphen P. 111, line 8 from bottom, for peuicaibictactoun read semiorbicularibus. P. 113, line 13 from bottom, for punctulata read punctulato. P. 115, line 10 from bottom, before minore insert folio. P. 116, line 10 from bottom, for bimellemetrali read bimillemetrali. P. 116, line 3 from bottom, for pedunculos implice read pedunculo simplice. P. 117, line 13 from top, for longa read longo. é P. 124, line 5 below Table III, for o.0048™ read 0.00048". P. 131, line 18 from top, for 1883 read 1833. P. 147, line 4 from top, for WILLIAM read EDWARD. P. 154, line 16 from top and footnote 15, for SARGENT read SARGANT. P. 156, line 19 from top, for cell read cells. P. 193, under title, for Prerce read PEIRCE, Pp. 195, 197, 199, 201, in folio, for PrERCE read PEIRCE. P. 206, line 21 from top, for edule read edulis. Pp. oeb, line 16 from top, for mere read near P. 323, in legend, for ‘‘lucidum” read ‘lucidus, fe Pp. 323, 325, in legend, for pseudoboletum read boletus. P. 330, line r9 from top, for vértiga read Maio P. 334, line 24 from top, for P. 335, line 2 from top, for tusgae read nrake P. 335, lines 3 and 5 from bottom, for pseudoboletum read pseudoboletus. P. 336, line 3 from top, for pseudoboletum read pseudoboletus. P. 336, line 5 from top, for 21007 read 21077 P. 338, lines 1, 7, 22, for pseudoboletum read pseudoboletus. @ THE BOTANICAL GAZETTE July 1908 Editors: JOHN M. COULTER and CHARLES R. BARNES CONTENTS A Study of Reduction in Oenothera rubrinervis Reginald Ruggles Gates Studies in Araceae é Jam-s Ellis Gow The Embryo Sac and Embryo of Gnetum Gnemon John M. Coulter Briefer Articles The Occurrence and Rate of Protoplasmic Streaming in Green- house Plants Grace L. Bushee On Plasmolysis Ww. J. V. Osterhout Current Literature - The University of Chicago Press ~ CHICAGO and NEW YORK : William Wesley and Son, London The Botanical Gazette A Montbly Journal Embracing all Departments of Botanical Science /Edited by JoHN M. CouLTER and CHARLES R. BARNEs, with the rai ag of other members of the F botanical staff of the University of Chicago. Issued July 23, 1908 . Vol. XLVI CONTENTS FOR JULY 1908. No. 3 A STUDY OF REDUCTION IN OENOTHERA RUBRINERVIS. CONTRIBUTIONS FROM THE HuLL BoTaNicAL LABORATORY III (WITH PLATES I-Ill). Reginald Ruggles Gares - - I STUDIES IN ARACEAE (wITH PLATES Iv-v1). /ames EllisGow - - - - = ae /THE nec ehas SAC AND EMBRYO OF GNVETUM GNEMON. PEACE, ee FROM E HULL BoTaANICAL LABORATORY I12 (WITH PLATE Vil). /John MM. Coulte 43 PBRIEFER ARTICLES THE aa ape ae AND RATE OF PROTOPLASMIC STREAMING IN GREENHOUSE PLANTS..— ~* el hee 2 . 50. On Piasmotysis. W./. V. Osterhout - - - - - - . z < > eet CURRENT LITERATURE : 7 BOOK REVIEWS - Bo Set ag A I 20 ae ee ree ae ees = THE ORIGIN OF A LAND FLORA. ELECTRO-PHYSIOLOGY. CONFERENCE ON GENETICS, NORTH AMERICAN TREES. MINOR NOTICES - : . - ‘ - - - - - : . De eae NOTES FOR SLUDAN PSE oe tt eee aS eS eee ee : The ood ties Sambhied is ee monthly. 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It is advisable to ‘ i ffere Sepiiaean if desired, may be ordered in advance of publication. ae nty-five separates of shea articles without covers will be supplied gratis. A table showing approximate cost of ots ional separate is printed on an order blank which accompanies the proof; a copy will be sent on reque Entered August 21, 1895, at the Post-Office at Chicago, as second-class matter, under Act of Paes March 3, 1879. ~ VOLUME XLVI NUMBER 1 BOTANICAL GAZETTE FULY 7908 A STUDY OF REDUCTION IN OENOTHERA RUBRINERVIS CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY III REGINALD RUGGLES GATES (WITH PLATES I-II1) The present contribution is a statement of some of the results obtained in the cytological study of Oenothera Lamarckiana and its mutants. Since these results have a more or less direct bearing on a wide range of fact and theory in various fields, their full discussion is reserved for a future time. The facts presented in this communica- tion will be taken almost wholly from the study of O. rubrinervis, one of the most vigorous of the mutants. Other papers will be presented later, giving the further evidence upon which the conclusions of this paper rest, and attempting to indicate their bearing on the general problems of cytology and variation involved. Material The plants from which the material for these studies was obtained were grown from pedigreed seeds of DeVries, the purity of these cultures being further proven, in some cases, by carrying on the pedi- gree for another generation before collections were made. The results of these cultures, which are still being carried forward to later generations, will be published at another time in connection with an account of other studies on variation and hybridization in Oenothera. In this way it is hoped, if possible, to correlate the cytological data with the work in hybridization and variation. It seems to the writer that only by thus combining cytological with experimental studies is an explanation of the peculiar and remarkable phenomena of variation exhibited by the Oenotheras to be reached. I 2 BOTANICAL GAZETTE [JULY The cytological studies presented here will be confined chiefly to the phenomena of synapsis and reduction in the pollen mother cell. Various forms have been studied, a complete series of stages being obtained in some forms and a partial series or only a few stages being examined in others. The forms investigated include (1) O. rubri- nervis, (2) O. Lamarckiana, (3) O. gigas, (4) O. nanella, (5) O. biennis cructata, a variety of the European O. biennis, (6) both O. lata (see 12) and O. Lamarckiana from the F , of O. lata O. Lamarckiana, and (7) plants resembling O. gigas, from the F, of O. lataXO. gigas. Pre- liminary reports have already been made upon some of these studies, in various connections (II, 12, 13, 14, 15). Reference will be made to some of these results later. The material from each individual was collected separately in nearly all cases, in order to observe possible individual differences in the same race, either in the number of chromosomes or in other cytological features. I am indebted to Mr. C. H. SHarruck for making a number of these collections. The material for the study of O. rubrinervis was obtained from a number of individuals grown in two different seasons and representing several strains derived from the same original pedigree. Sections were cut from six of these, and it may be stated here that in O. rubrinervis no individual differences were discovered, either in the number of chromosomes, which was 14 in all cases, or in any other features. In some of the other mutants, also, a number of individuals were examined. It was found necessary to reserve the account of O. gigas, which presents several features of special interest, for a separate paper. A preliminary report on this form has already been made (14, 15). For various reasons, O. rubrinervis was chosen as the most favor- able form for a thorough study of synapsis and reduction. The nuclei and chromosomes of Oenothera are small, and for this reason the selection of the most favorable type for study is a matter of some importance. In O. rubrinervis the pollen mother cells, although they vary much in size, are usually considerably larger than in O. Lamarckiana, the nuclei being also proportionately larger. The reason for this will be explained later. The chromosome number being low in most of the forms (2% =14, «=7), they can be counted without any difficulty, notwithstanding their small size. Another 1908] GATES—REDUCTION IN OENOTHERA 3 notable advantage in comparing this with other studies in reduction is in the shape of the chromosomes, which are globular or somewhat oblong or cylindrical in most stages of mitosis, and are never greatly elongated or looped. For this reason it is a comparatively easy matter to obtain accurate counts of the chromosomes in the pollen mother cells of any of the forms. This shape is also found to be very advantageous in a study of the events of reduction following synapsis. The appearances are clear and easily interpreted, in striking contrast to the forms with long twisted chromosomes, such as have been made the basis of many of the studies on reduction in plants. On the other hand, the somatic nuclei and chromosomes are very much smaller, and in metaphase the latter are elongated and looped, making it impossible to count them with the same degree of accufacy. Some of these appearances have already been described elsewhere (12, p. 19). Thus while it was found that the chromosomes could be counted almost equally well in pollen mother cells of all the forms studied, O. rubrinervis was found to be especially favorable for the investigation of reduction phenomena, especially the events of synapsis and the prophases of the heterotypic mitosis. The account given here will refer throughout to O. rubrinervis, with occasional comparisons with other forms. Later papers will take up these other forms in detail, in so far as this is necessary after the account presented here. Special attention will be given at that time, in particular, to the later stages, beginning with the telophase of the heterotypic mitosis, and also to the interesting conditions in some of the hybrids. The detailed account in O. rubrinervis will not be carried farther than the metaphase of the heterotypic mitosis, at which time the essential events have already taken place. Methods The usual methods of cytological technique were employed, Various chrom-acetic and chrom-osmo-acetic solutions being tried until satisfactory fixation was obtained. The thickness of the sec- Hons varied from 4 to rom#. The latter thickness was found most favorable for counting chromosomes, because it is somewhat greater than the diameter of the nuclei, many of which in such sections were therefore uncut. It is possible to determine easily whether a nucleus has been cut by the knife by examining it in low and high focus. ‘The 4 BOTANICAL GAZETTE [yuLy chromosomes in such uncut nuclei can then be counted with absolute accuracy, either in the prophase of the heterotypic mitosis before the disappearance of the nuclear membrane, or in the telophase after the walls of the daughter nuclei are formed. In nearly every individual examined, large numbers of such cases, all yielding the same result, were counted before the number was finally determined upon. The chromosomes could also be counted in certain positions on the spindle, particularly in anaphases, but in metaphase they were usually too closely grouped to allow of satisfactory counting. In the second division, particularly in the forms having seven chromosomes as the gametophytic number, the chromosomes could be counted with certainty in almost any stage of mitosis. The thinner sections were used chiefly in the study of spirem and synapsis stages, although here also the comparatively short length of the thickened spirem frequently made it advantageous to study uncut nuclei in which the spirem could be followed throughout its length. Of the various stains Heidenhain’s iron-hematoxylin was found to be superior for chromosome counting and for clear differentiation of chromatic structures in nearly all stages of synapsis and reduction, safranin-gentian being used occasionally for comparison or for differentiating particular cytoplasmic structures. Orange G was also used with the iron-alum stain for bringing out clearly certain special features, particularly the protoplasmic connections between mother cells, which will be described later. Description EARLY STAGES Some of the very early stages of the anthers, previous to the forma- tion of mother cells, have been studied particularly with the purpose of tracing the origin of the bodies which were called heterochromo- somes in my first paper. The provisional use of the name was based on fhe very close resemblance of these bodies to the chromo- somes in appearance, and their frequent presence close by, or in some Cases apparently attached to, the heterotypic spindle. They were not stated to pass undivided into one of the daughter nuclei, as misquoted by TIscHLER (32), but to remain outside in the cytoplasm Where they gradually disappear. The study of their early history 1908] GATES—REDUCTION IN OENOTHERA 5 shows that no line of distinction can be drawn between them and the large body readily recognized as the nucleolus. They are then smaller nucleoli, not differing essentially in origin from the single larger body which is almost constantly present in the mother cell during synapsis and prophase, but diverging from the latter some- what in their later history. In the earliest stages studied, the young meristematic cells of the anther primordia are very small (figs. 1, 2), and the tissues are wholly undifferentiated, except the epidermal layer. Usually several smaller nucleoli are present in each nucleus of the meristematic cells, in addi- tion to the larger nucleolus. Compared with the cells of the anther wall when they are no longer meristematic, the smaller nucleoli of the former are about the size of the nucleoli of the latter, which are approximately equal in size. There is nothing in the latter corre- sponding to the larger nucleolus of the meristematic cells. Probably afterward one of these nucleoli enlarges as the cell increases in size, or it is possible that the nuclei of meristematic cells are always derived from previous ones which already possess a large nucleolus. Chromatic staining bodies are also found closely appressed to the nuclear membrane in all the meristematic cells (jigs. 1, 2). This tendency for chromatic material to accumulate on the nuclear walls gives these nuclei a characteristic appearance. ‘These bodies often appear like a thickening of the membrane itself. At the next stage studied many cell divisions have taken place, and the sporogenous, tapetal, and wall tissues have been differentiated. The sporogenous cells have increased enormously in size, and form a single row in longitudinal section down the center of the anther, the walls of these cells being especially thickened and distinct (fig. 3). The cells of the surrounding tapetal layer have also increased greatly in size and are distinctly marked off from the sporogenous row. In the Sporogenous cells the nuclei (fig. 4), though much increased in size, have not increased in proportion to the cytoplasm. The large nucleolus, much larger than in the earlier stage, is now a conspicuous object in the nucleus. Smaller nucleolar bodies are almost invariably Present, but masses are no longer found attached to the nuclear membrane. (The characteristic masses, however, may remain for some time attached to the nuclear walls of the tapetal cells). 6 BOTANICAL GAZETTE [JULY Figs. 5-10 are from drawings of other nuclei at this stage of develop- ment. In the majority of cases one or two smaller nucleoli occur in addition to a single large one, but rarely (fig. 6) two large nucleoli of equal size may be found; and very frequently the number of small bodies, of equal or unequal size, may be greater, reaching as many as five or six. Figs. 5, 7, 8, 9 show these in various stages of fusion with each other and with the large nucleolus.: They are thus not in any sense autonomous bodies. It appears that usually these fusions take place until only one large nucleolus and one or two smaller ones are present during synapsis and diakinesis. But occasionally the fusions do not take place, and several of these bodies may then be present in the later stages. The number of these nucleoli finally present depends, then, largely upon the amount of fusion which has previously taken place between them. In the later stages one large nucleolus is almost invariably present and usually a smaller one bearing a certain proportion to the larger in size, though the latter may vary in size and number as already stated. There is usually a clear area around the large nucleolus, as in the earlier stage, and threads of the reticulum may or may not cross this and appear to be attached to the nucleolus (fig. 4). The reticulum of the cytoplasm usually stains rather more deeply at this time than that of the nucleus. It may as well be stated at this time that in the resting nuclei of the pollen tetrad and in.the nuclei of the nearly mature pollen grains of Oenothera one finds (fig. rr) the same condition of the nucleoli as in the mother cells, namely, usually one large and one small nucleolus bearing a rather definite size relation to each other, with sometimes additional small ones. The sporogenous rows are differentiated from the tapetum by the greater growth of the cells, nuclei, and nucleoli of the former. At the same time they are distinctly marked off by the formation of a continuous thickened wall between tapetum and archesporium (fg. 3). It.is obvious that as the cells and nuclei increase in size, the nucleolus grows also. Up to the time of synapsis the mother cells usually form a compact tissue, but about this time the cells begin to iss NICHOLS (21) figures what are in all probability stages of fusion of la and small nucleoli in Sarracenia pollen mother cells, but interprets them as a buddi off of small bodies from the nucleolus. e budlike attachments to the nucleolus frequently observed by other authors are doubtless to be explained in like manner. 1908] GATES—REDUCTION IN OENOTHERA 7 break apart at the corners where they meet, and before diakinesis is reached they are completely rounded off and independent, or they frequently remain connected with other mother cells only at the ends. In the meantime the cavity of the loculus grows rapidly, so that the mother cells, in normal development, usually lie loose in the cavity. The events of synapsis and reduction usually go forward simul- taneously throughout a flower, with comparatively little variation in the different parts of the same loculus or in the different anthers of a flower. In one flower, however, wide variation was found in different anthers, but comparative constancy in the loculus. One anther of this flower was in synapsis, another in diakinesis, another in meta- phase of the heterotypic mitosis, and in still another some of the mother cells had completed the second mitosis. No abnormalities in the cytological condition of this flower were observed. SYNAPSIS After the stage described in fig. 4, the nucleus increases greatly in size, but without an appreciable increase in the size of the cell. The single row of sporogenous cells divides, so that there are usually two rows of pollen mother cells. Occasionally three or more mother cells are found in the cross-section of a loculus. In general there are fewer divisions than in the other forms, and this is at least one of the reasons why the mother cells are on the average larger than, for example, in O. Lamarckiana. The resting nucleus of the pollen mother cell increases in size and begins to show signs of approaching synapsis. Figs. 12, 13, 14 show stages in the beginning of this process. A number of these Stages were found—although they are uncommon—in the same sections with regular synapsis stages. In some cases they occurred side by side with mother cells in which the synaptic knot had already been formed. A complete series of stages may be found in the same section, from the beginning of contraction to the formation of a close synaptic ball. The cytoplasm in these cells shows no contraction whatever, but is perfectly fixed. For this and other reasons there can be no doubt that this is a real contraction stage, leading to synap- sis, and not a result of imperfect fixation, as one might judge on first examination. 8 BOTANICAL GAZETTE [yuLy That these nuclei are going into synapsis and not coming out is shown by several features: (1) the extremely delicate character of the threads, like those of the resting nucleus; (2) the fact that the periphery of the reticulum as it contracts frequently preserves perfectly the curved outline of the nuclear wall (fig. 12); (3) immediately after synapsis the thread is somewhat shorter and thicker than previously and appears to be continuous, while in the earlier contraction stages we still have the appearance of a reticulum (jig. 13).2_ As the con- traction progresses, the threads are gradually rearranged from an anastomosing reticulum to a very long and continuous delicate thread. The exact manner of this rearrangement could not be observed, but one finds many transitions (fig. 14) from the anastomosing reticulum of the resting nucleus to the closely coiled and apparently continuous spirem of the synaptic knot (fig. 15). The contraction may take place from one side of the nucleus, leaving the reticulum attached for a time to the nuclear membrane at one point (fig. 13), or it may take place simultaneously from all sides (fig. 12). A few threads of the reticulum usually remain attached for a time to the nuclear membrane while the contraction is going on. These are drawn in finally as the synaptic ball becomes more compact. The small number of these intermediate stages found indicates that they are passed through rather rapidly, the frequency of the occur- rence of synapsis stages indicating, on the other hand, that this con- dition is of considerable duration. No indication of a doubling or pairing of the threads during these intermediate contraction stages could be observed, though they were carefully searched for. Moreover, in the earliest stages of the synaptic ball the thread appears to be as thin and delicate as in the reticulum, which does not favor the view that a pairing has taken place. The evidence, then, i) © PLATE V VIGAL GAZETTE, XLVI GOW on ARAGEAE JCAL GAZETTE, XL VI PLATE. Vi : ' GOW on ARACEAE THE EMBRYO SAC AND EMBRYO OF GNETUM GNEMON CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY I12 Joun M. COULTER (WITH PLATE VII) Gnetum Gnemon has been made conspicuous among the other species of Gnetum chiefly by the investigation of Lorsy published in 1899. The structures described were of such interest that it seemed desirable to supplement the somewhat incomplete account by a further examination. Accordingly material was obtained from the Philippine Islands and from British Guiana; the former from Dr. H. N. Wuuirrorp, and the latter from Mr. A. W. BaRtLert, director of the Botanic Garden at Georgetown. This material was first assembled by Dr. W. J. G. Lanp, of this laboratory, in connec- tion with his investigation of Ephedra; and he has kindly turned it over to me for separate study. The preparations and drawings were made by Dr. SHicfo Yamanoucui, of this laboratory, and to his technical skill the results are largely due. The material included stages from two successive seasons, but unfortunately many intervening stages were not represented, so that no continuous account can be given. However, certain facts have been discovered that supplement and correct the previous accounts. EMBRYO SAC _ Lorsy described the embryo sac of G. Gnemon as showing an interesting deviation from those found by KarsTEN? in other species of Gnetum. Instead of containing only free nuclei at the fertiliza- tion stage, the embryo sac of G. Gnemon was described as containing Tsy, J. P., Contributions to the life history of the ean Gnetum. Ann. Fatal he Wittens II. 1:46-114. pls. 2-11. 1899. 2 KarsTEN, H., Bot. Zeit. 50:205-215, 221-231, 237-246. pls. 4,6. Roxas Ann, Jard. Bot. Buitenzorg 11:195-218. pls. 17-19. 1893; Cohn’s Beitr. Biol Pflanzen 6: 337-382. pls. 8-11. 1893. 43] (Botanical Gazette, vol. 46 44 BOTANICAL GAZETTE [JULY a compact antipodal tissue, sharply distinct from the micropylar chamber with its free nuclei. As a consequence, the embryo sac of G. Gnemon has been used ever since as illustrating a female game- tophyte intermediate in structure between the tissue-filled sacs of Ephedra and Tumboa on the one hand, and the sacs of other species of Gnetum, which contain only free nuclei. Later the same investi- gator in reporting parthenogenesis in G. Ula? described the embryo sac of that species as being of the G. Gnemon type. Our material of G. Gnemon does not confirm this account. At an early stage of the embryo sac, eight nuclei are observed grouped near the center (fig. 1), the sac being invested by the loose tissue of the nucellus. At a somewhat later stage the nucellar cells at the chalazal end of the sac are strikingly differentiated (jig. 2), becoming _ more and more compactly arranged, gradually obliterating the intercellular spaces, and taking on the appearance of glandular cells. The relation of this tissue in its early stage to the embryo sac is shown in jig. 2a, As vacuolation proceeds in the sac and the free nuclei become parietally placed, this “pavement tissue” becomes more compact and extends deeper into the chalaza (figs. 3, 34). Still later it spreads laterally below, until it becomes fan-shaped in section (figs. 4, 4a), but it is always very distinct in contour and sharply marked off from the surrounding nucellar tissue. At the fertilization stage (figs. 4, 5) the sac contains only free nuclei, which become somewhat grouped at the antipodal end (fig. 5), but there is no walled tissue. Spreading below the sac, however, the mass of nucellar pavement tissue shows a definite contour, which might be merged in imagination with that of the sac and thus mistaken for a compact tissue within the antipodal end of the sac. Lomsy’s figures show the real contour of the sac, and his antipodal tissue is clearly this glandular pavement tissue developed in the chalaza So far as the sac of G. Gnemon is concerned, therefore, its fertiliza- tion stage is that described for other species of Gnetum. It will be noted that after the fertilization Stage is reached (fig. 5) the pav& ment tissue begins to lose its glandular character; and later it is : destroyed entirely by the growing endosperm. Lotsy, 3 pas ee Parthenogenesis bei Gnetum Ula Brongn. Flora 92 2397-404 bls. 9, Io. 1903. 3 1908] COULTER—GNETUM GNEMON 45 ENDOSPERM A year later, the endosperm has destroyed all of the nucellar tissue except a very small amount at the tip (jigs. 6, 6a, 7a), and it is clearly differentiated into a central region of smaller, more compact cells, and a more extensive peripheral region of larger and looser cells. In destroying the nucellar beak, a curious result is observed. The central region of the endosperm advances into the beak and then spreads laterally (jig. 6). In the meantime the peripheral region advances more slowly toward the beak, and as a consequence a ring of nucellar tissue is pinched between two growing masses of endosperm. The growth of the endosperm into the chalazal region - also results in pressure toward the beak, so that the pinched nucellar tissue is under considerable pressure and becomes completely disor- ganized. Under this pressure some of the adjacent endosperm cells also become disorganized. | Tn ovules of the preceding year, at the fertilization stage of the embryo sac, a curious disorganization of some of the cells of the nucellar beak was observed (fig. 5a). Two transverse rings of cells, several layers beneath the epidermis, begin to disorganize; later the epidermis becomes involuted between the disorganized rings, resulting In a deep groove around the nucellus. The epidermal cells remain rh Vigorous in appearance, and when the endosperm develops into this region the groove disappears. The cause and the significance of this disorganization and of the temporary. involution of the epi- dermis cannot be suggested. EMBRYO Lotsy has described the entrance of pollen tubes into the embryo Sac, the fertilization of the free eggs, the excessive elongation of the fertilized eggs to form suspensors, and the cutting-off of the embryonal cells at the tip of the suspensor. Later stages in the development of the embryo have been described by Bower,‘ but the intermediate Stages have not been observed. Fortunately our material from the Philippines contained them, and revealed an unexpected situation. When the endosperm has become fully developed, its peripheral 4 . : Se Ra Da rata hi ete Om 46 BOTANICAL GAZETTE [yULY region contains a tangle of long, tortuous, and branching suspensors (figs. 6, 7), which are difficult to trace. During the formation of a suspensor by a fertilized egg, free nuclear division occurs, resulting in a few nuclei (four in fig. 7) distributed along the suspensor. Usually between these nuclei transverse walls are formed by the development of a cleavage plate from the wall of the suspensor. A cell at the tip of the suspensor is cut off in the same way, and contains one of the free nuclei, which becomes associated with numerous starch grains (jig. 7). In this terminal embryonal cell free nuclear division continues (figs. 8, 9, 10), accompanied by cleavage walls, until a multicellular embryo is formed. In figs. 9 and zo it will be observed that this cleavage apparently continues until uninucleate cells are produced; and in our material this stage is reached first by a group of cells on . one side of the embryo. It could not be determined whether this group holds any relation to a body region or not. It has been supposed that in the embryogeny of Gnetum the preliminary stage of free nuclear division, common to other gymno- sperms, had been eliminated; and that the first nuclear division was accompanied by wall formation, as in angiosperms. In Gnetwm Gnemon, however, free nuclear division not only characterizes the proembryo, but also the early stages of the embryo. The case may be compared to that of Ephedra,’ in which free nuclear division within the fertilized egg results in eight independent proembryonal cells, each of which continues free nuclear division and develops aS _— a suspensor, which by a cleavage wall cuts off the terminal embryonal . cell. In Gnetum the suspensor is formed by the fertilized egg instead of by a proembryonal cell, but the number of free nuclei formed by — the egg in each case is approximately the same. | INTEGUMENTS ‘ The mature seed of Gnetum Gnemon gives an opportunity 1? : compare the integument and testa with those of other gymnosperms. Fig. 6a shows the seed slightly stalked within the so-called “perianth,” which is fleshy. Two integuments are evident, and they develop in 3 S LAND, W. J. G., Fertilization and : ° ts x ds embryogeny in Ephedra trifurca. BOT GAZETTE 44:273-292. pls. 20~22, 1go7. . J pare we a 1908] COULTER—GNETUM GNEMON 47 basipetal succession. The inner one extends above to form the elongated micropylar tube, and at the maturity of the seed completely invests the nucellus (at this time replaced by the endosperm) as a papery layer. The outer integument becomes differentiated into an outer fleshy layer (white in the figure) and an inner stony layer (black in the figure), the latter completely investing the seed, the former being chiefly developed in the region of the nucellar beak. Two sets of vascular strands are present, the outer set traversing the fleshy layer of the outer integument, the inner set traversing the Inner integument. In Cycadophytes, Ginkgoales, and Coniferales, a single integu- ment becomes differentiated into a testa of three layers: outer fleshy, stony, and inner fleshy. In Gnetum the same three layers are Present, but the inner fleshy one has become differentiated in onto- geny as a separate integument. In all cases, this innermost layer finally forms a papery lining of the stony layer. Among the Pinaceae the outer fleshy layer is present in the integument, but it does not develop into the extensive pulpy investment that characterizes the Cycadales, Ginkgoales, and Taxaceae, a fact which is probably associated with the close investment of the seeds by the scales. The variation in the distribution of the vascular strands among these layers is interesting. Among the more primitive Cycado- filicales and Cordaitales, in which the nucellus is relatively free from the integument, the outer set of strands traverses the outer fleshy layer and the inner traverses the peripheral tissue of the nucellus. In other Cycadofilicales and Cordaitales, however, and in Cycadales which the nucellus and integument are free only in the region of the nucellar beak, the inner set of vascular strands traverses the aner fleshy layer of the integument; and this is the condition in Gnetum, except that this layer has become differentiated as an inner integument. In Ginkgoales the outer set of strands (belonging to the — fleshy layer) is suppressed; in Taxaceae the inner set (belonging to the inner fleshy layer) is suppressed; and in Pinaceae th are suppressed, 5 MALE GAMETOPHYTE It was a disappointment that the development of the male gameto- phyte was hot secured, for it is only known among Gnetales in Ephe- 48 BOTANICAL GAZETTE [yuLy dra, in which it has been described by Lanp.® The development of the tetrad was observed; and although the early anaphase of the first mitosis was not available for the counting of chromosomes, the — late prophase of this mitosis and the anaphase of the second mitosis showed clearly that the chromosome numbers are 12 and 24. SUMMARY 1. The “antipodal tissue” described by Lorsy as occurring in Gnetum Gnemon at the fertilization stage is a sharply differentiated nutritive tissue developed in the nucellus beneath the embryo sac, which at this stage contains only free nuclei, as described for other species of Gnetum. 2. Embryo formation begins with an excessive, suspensor-like elongation of the fertilized egg, accompanied by free nuclear division and cleavage walls; and the continuation of free nuclear divisions and cleavage walls in the embryonal cell until a multicellular embryo is formed. 3. The endosperm encroaches upon the tissue of the nucellar beak with some irregularity, an irregularity which reaches its extreme expression in Torreya, with its so-called ‘“‘ruminated” seeds. 4. The inner integument of the ovule is the morphological equiva- : lent of the “inner fleshy layer” of the single integument of other — gymnosperms; and the occurrence of two sets of vascular strands — is a relatively primitive condition, which has been departed from by Ginkgoales and Coniferales. 5. The chromosome numbers are 12 and 24. Tuer UNIversITY oF CHICAGO EXPLANATION OF PLATE VII Fic, 1.—Embryo sac at an early stage, with centrally placed group of eight free nuclei; the cell above, with a large nucleus, is another embryo sac. X50* — Fic, 2,—Somewhat later stage of embryo sac (all the nuclei not included); showing the beginning of the formation of the pavement tissue; a second em sac is also shown. X 500. F IG. 2a.—An ovule at an early stage, showing the two integuments and . relation of the pavement tissue and embryo sac to the nucellus at the stage show”: in fig. 2. X4o. °Lanp, W. J. G., Spermatogenesis and oogenesis in Ephedra trijurca. GazETTE 38:1-18. pls. I-5. 1904. aa N = . —— Fe NICAL GAZETTE, XLVI PLATE Vil =, NS \— ‘ om \S eo, \\ DAL YAR aS Ss tsps 4 Anasgnens aes AS Se ay No, Sh .% COULTER on GNETUM 1908] COULTER—GNETUM GNEMON 49 Fic. 3.—Further development of pavement tissue; vacuolation of the sac. X 250. Fic. 3a.—An ovule, showing general relation of regions shown in fig. 3; the tip of the nucellus has broken down (the only indication of a pollen chamber). X40. Fic. 4.—Further pie Se of pavement tissue and embryo sac (probably fertilization stage). 220. Fic. 4a.—An eek showing relation of regions shown in fig. 4. X40 Fic. 5.—Later stage of embryo sac (possibly still in patra at ‘ike’: with grouping of nuclei in the antipodal region, where tissue formation probably begins; beginning of disorganization of pavement tissue. X2TOo. Fic. 5¢.—An ovule, showing relation of regions shown in fig. 5; also the curious deotguatabean of cells and infolding of the epidermis in te nucellar beak. X4o ; Fic. 6.—Tip of seed; small amount of tissue of nucellar beak not destroyed by endosperm; differentiation of central and peripheral regions of endosperm, the former having advanced into the center of the nucellar beak and spread laterally, resulting in crushing nucellar tissue against the encroaching peripheral region of endosperm; sections of two suspensors shown. X 40 FG. 6a.—Mature seed invested by the fleshy ‘“‘perianth;” outer integument differentiated into outer fleshy (white) and stony (black) layers; inner integu- ment forming the micropylar tube; at apex of nucellus is Figg the remains of the nucellar tissue (shown with greater magnification in fig. 6). Fic. 7.—A proembryo, showing the branching, suspensor-like ce of the egg, with free nuclei and cleavage walls; also the embryonal cell containing a nucleus and numerous starch grains; sections of other suspensors shown, and also a small portion of the undestroyed tip of the nucellus. X 4o. : IG. 74.—Outline to show the relation of parts illustrated by fig. 7. X3. Fic. 8.—Beginning of embryo formation by the embryonal cell, showing free nuclei and the beginning of a cleavage wall; a cleavage wall in the suspensor also shown. X 250. IG. 9.—Section of later stage of embryo, showing free nuclei, cleavage walls, and the beginning of small-celled tissue at one side. 2TOo. Fic. 10—An embryo reconstructed from serial sections, showing free nuclei, cleavage walls, and the beginning of uninucleate cells. <140. BRIEFER ARTICLES THE OCCURRENCE AND RATE. OF PROTOPLASMIC STREAMING IN GREENHOUSE PLANTS In the Botanical Laboratory of Smith College, under the direction of Professor GANONG, various lines of investigation are in progress to determine which plants of those available during the school and college year are best adapted for educational work in each of the principal physiological processes. The results are appearing from time to time in the BOTANICAL AZETTE.! The object of the present inquiry is to discover which of such plants show protoplasmic movement, in which the streaming is most active, and at what temperatures. The development and sum of our knowledge of protoplasmic streaming — may be traced through Prerrer’s Plant physiology, which needs to be supplemented, however, by the references under ‘‘Protoplasmabewegung” in Just’s Jahresbericht, and by the admirable new work of Ewart, On the physics and physiology of protoplasmic streaming in plants (Oxford, Clarendon Press, 1903). Streaming has been found in a great number of plants of the most diverse groups, from fungi to phanerogams, and in the most different structures, including the exposed cells of algae (where it reaches its finest display), emergences and hairs on various organs (notably stamens), root hairs (where it has been found in at least sixty-five families), ; if plasmodia of myxomycetes, mycelia of molds, pollen tubes, the b' young wood, and medullary rays of various trees, stamens, petals, and other parts. The rate of the streaming has been measured by several observers in different plants, and ranges from zero up to an extreme of 1om™™ per minute, but in each plant the rate is dependent-upon temperature and rises from a minimum of no movement up to an optimum of greatest movement, whence it sinks to a maximum of no movement, which cardinal — _ tory guesses range all the way from “pathological,” through ‘incidental, to “‘ecological,”’ the most reasonable of the latter (especially in view of its greater activity in large cells) being that it is a mechanical aid to diffusion. Protoplasmic streaming is a striking and perhaps a fundamentally — important phenomenon, well worth demonstration to elementary eet * 402302. 1905; 45:50. 1908; and 45:254. 1908. Botanical Gazette, vol. 46] 1908] BRIEFER ARTICLES 51 and measurement by advanced ones. Of the plants available for the pur- pose in winter, namely, those which are or may readily be grown or kept in greenhouses or houses, the best known heretofore are as follows: species of Chara and Nitella, which may be kept over winter in tubs under the green- house benches; Elodea and Vallisneria, responsive to the same treatment; Tradescantia zebrina or wandering Jew, very commonly grown, and T. virginica (or pilosa) which can be kept part of the winter if planted on a greenhouse bench and cut back until July or August; squash or tomato, which can be grown from seed in two or three weeks; root hairs of mustard and other plants, which can be grown to perfection in wet, covered flower-pot saucers; heliotrope and pelargonium, The brevity of this list in plants presenting material ready at all times led me to undertake a systematic search for others through a range of educational greenhouses, and I was successful in finding the considerable number of new cases marked by the asterisks in the table below,? I undertook to determine, upon a uniform system, the rate of movement, both for these and for the other common forms, at the two temperatures Practically most important, namely 20° (approximately ordinary room temperature) and the optimum; and the results are recorded in the table. For the control of temperature I used GANONG’s temperature stage, with the method, including standardized ocular micrometer and metronome, described in his Laboratory course in plant physiology. The figures in the table are averages of two or more determinations from different specimens : : r d €xcept in a few cases of the optimum, where onl ihc seapaeeee GREENHOUSE PLANTS SHOWING PROTOPLASMIC STREAMING, WITH ITS RATE NAME OF PLANT PARTS OBSERVED @ 20° | Optimum ae *Abuti : Abutilon striatum hyb. unicellular hair from surface of | .161 | .773@32° * ‘i : hair from calyx -016 Ampelopsis Veitchii (Bos- | unicellular hair from under side of | .138 | .368@36° heed midrib *Azalea ‘iva (oat) root hair of seedling +322 s Bras es cell of hair from leaf blade -138 | -322@34 ica alba (white mustard)| root hair 322 "Those marked by ian asterisk are here recorded for the first ime. . _ 7 As concerns outdoor plants for this same purpose there is a paper entitled ““Sub- al for Protoplasmic movements,” by B. D. HatsTED, in Bull. Bot. Depart. Iowa Agric. Coll. 1888; 578. It enumerates‘ten common plants. 52 BOTANICAL GAZETTE [JULY (mm. per min.) NAME oF PLANT PARTS OBSERVED ese h . @ 20 Optimum *Campanula glomerata (bell } unicellular hair from leaf blade or | .258 644@38° — ower etiole a *Capsella Bursa-pastoris unicellular hair from flower stalk 215 483@32 (shepherd’s purse) g : *Cestrum elegans unicellular hair from stem or veins 161 | .428@35 on under side of leaf s *Coleus Blumei Verschaf- cell is hair from stem at node or 276 892@35 feltii of petiole Cucurbita maxima (squash) | cell ar hair ~- — 258 859@ 32° *Cuphea hyssopifolia cell of hair fro 121 258@ 34" *Cuphea i | (cigar plant) cell of hair fro pees -048 | .2 15@30" Sinden +3 sill eee -adetls of len 604 | .966@30" *Fuchsia ae aieilvlan hair oer eas stalk 175 322@ 3 *Gaillardia poowitcks cell of hair from 227 703@ 36° 2 *Gloxinia speciosa cell of hair from nti or petiole 322 |I .054@30" cell of hair from leaf op 351 |1.088@30 site annuus (com- | cell of hair from edge of petiole 195 .420@35 mo jower) cell of hair from midrib 08 <= Heliotropium peruvi unicellular hair from stem, surface | .121t | .386@34° m helio Sacer ag of leaf, or under side of midrib . sHibiecks | Cooperi (rose mal- oot hair from petiole or un- 75 oy — E der side of midri é *Isoloma hirs cell of hair from oo -193 Seek mage ver hey Seater cell of hair from s 242 Lobelia unicellular ue ee leaf edge, | .297 petiole, or stem *Lopezia albiflora aectiiae: kate from eg -193 unicellular hair from lea -322 ee } rom see side of | .121 mi Nitella (common species) ab ells 1.610 Pelargonium quercifolium cell of conical - from petiole or | .322 (oakleaf pelargonium) surfac ycopersicum t cell of tae Gant stem, leaf edge, or| .386 (commo ) vein *Oxalis Bowi cell of hair from leaf-edge . 242 *Primula ob¢onica ‘piper cell of hair from stem or leaf - 276 *Saxifraga cotyledon palmata] cell of hair from edge of leaf -176 (saxifrage, rockfoil) axifraga sarmentosa (beef- | cell of hair from flower stalk Sab steak saxifrage) cesar a pes (cineraria)| cell of hair from under surface of leaf| .193 Streptosolen Jamesonii cell of hair from stem or leaf blade | .183 esscantia nic cell of stamen hair 242 ers escantia zebrina (wan-| cell of stamen hair 386 dering Jew *Whitlavie ras aa cell of hair from leaf edge 107 unicellular hair from petiole or calyx} .242 ~ * . * . leaf blade -193 cell of glandular hair from leaf blade| .138 * Those marked by an asterisk are here recorded for the first time. 1908] BRIEFER ARTICLES 53 This table shows that suitable material can easily be obtained in winter for the demonstration of protoplasmic streaming. Of the plants studied, I should recommend Nitella and Elodea as good examples of rotation; Gloxinia speciosa, Tradescantia zebrina and virginica, Abution striatum (hyb.), Lycopersicum esculentum, W hitlavia grandiflora, Cucurbita maxima, Lobelia Erinus, and Saxifraga cotyledon palmata for circulation. Gloxinia Speciosa is especially good, as the entire hair cell can be brought within the range of vision, and a constant change observed in the arrangement of the strands, circulation passing into rotation as the temperature rises. Campanula, Lobelia, Vinca, Streptosolen, Capsella, and Ampelopsis have markings on the cell wall which obscure the view of the protoplasm to some extent. A complete study of the streaming involves the measurement of its rate at Various temperatures from minimum through optimum to maximum. Results of such study, expressed in a graph, are available for Chara, Elodea, and Vallisneria in DaveNport’s Experimental mor phology (12226), and for a common Nitella in GANONG’s Laboratory course in plant physiology (p. 19). My own graph for Tradescantia shows a curve much flatter than that above mentioned for N itella, though otherwise somewhat similar to it— Grace L. BUSHEE, Smith College, N orthampton, Mass. ON PLASMOLYSIS According to the conception of plasmolysis developed by DE VRIES and EFFER, the contents of a cell contract and round up when it is placed in a ution whose osmotic pressure exceeds that of the cell sap. This is explained by supposing the outer layers of protoplasm to be impermeable to the substances in solution which produce the osmotic pressure. If the Protoplasm is permeable to these substances, either wholly or in part, deviations from the rule given above will occur. Deviations have in fact been described by several authors and explained by supposing the Protoplasm to be more or less permeable to the substances in solution, which enter the cell sap and increase its osmotic pressure. : I Propose in this paper to describe deviations which range from those which are very slight to those which are of extraordinary intensity, the ee of whose nature is entirely different from the one mentioned ve. Pr sol . My attention was first called to these deviations some three years ago y the results of some of my experiments on the réle of osmotic pressure* TA bri : ae ed ; ‘ 23227, an . lee of these investigations appeared in oo coge — ot. ee BOTANICAL GAZETTE 7 [uty in marine plants. I then experimented on fresh-water plants and found even more striking results. In order to make clear the nature of these results I will describe an experiment with Vaucheria. Zoospores which had attached themselves to slides were allowed to germinate and produce short tubes. The slides were then transferred to 0.0937 m NaCl solution. In the course of a few minutes the protoplasm began to contract away from the cell wall. _ The solution was apparently strong enough to produce plasmolysis and I pre- pared weaker ones. These, however, produced the same effect, taking more time to do so in proportion as they were weaker. It then occurred to me that the effect was not due to osmotic pressure but to a contraction of the protoplasm due to the chemical action of the salt. In order to test this idea I endeavored to determine how dilute the solu- tion could be made and still produce this effect. I found that even 0.0001 m solution produced it, though usually only after a day or so. The experi- ments are repeated several times with Kahlbaum’s C. P. sodium chloride which I had recrystallized six times. The result remained the same.? I then tried to do away with this effect. This is easily accomplished by adding a little CaCl,. The addition of CaCl, in solid form increases the osmotic pressure of the solution, but in spite of this it prevents the contrac- tion of the protoplasm away from the cell wall. If one molecule of CaCl, is present for every hundred molecules of NaCl, the algae endure solutions of — o.1 m (that is to say, solutions with a thousand times greater osmotic pressure) without any contraction or apparent plasmolysis. I have since experimented with a great variety of salts and combinations of salts which produce effects similar to those just described. Ihave found — that all the plants with which I have experimented (algae, fungi, mosses, liverworts, Equisetum, flowering plants) give similar results, though : most of them are much less sensitive than Vaucheria. s After these experiments I was in no way surprised when I found that water distilled from a metal still could produce apparent plasmolysis within a few minutes, and that this could be prevented by the addition of various _ substances. i In what way is the contraction just described distinguishable from true plasmolysis? In many Cases it cannot be so distinguished at all> by its od Vaucheria from other localities and especially in later stages proved less sensitive : to the action of NaCl. Cf. Jour. Biol. Chem. 12363. 1906 oO * It is possible that the results described by Duccar (Trans. St. Louis Acad. Ste 103473. 1906, and Taxeucut (Bull. Coll. Agri. Imp. Tokyo Univ. 71623. 1908) af explicable on this basis. 1908] BRIEFER ARTICLES 55 appearance, but only by comparison with other (especially non-toxic or balanced) solutions, or by determination of the freezing-point of the cell sap. The protoplasm rounds up just as in true plasmolysis, and may even subsequently recover and expand in characteristic fashion when transferred to distilled water. It may happen that a contraction is caused by true plasmolysis, but the subsequent chemical action of the salt renders the protoplasm unable to recover and expand when the cell is transferred to distilled water. Such recovery cannot therefore be used as a means of distinguishing true plas- molysis from a contraction due to chemical action. In some cases the contraction may be distinguished from true plasmolysis by the irregular outline of the contracted protoplasm. On looking over the literature it becomes evident that such precautions as are necessary to distinguish this contraction from true plasmolysis have not been generally observed in making plasmolytic determinations, and a revision of such determinations is necessary. Determination of the freezing- Point of the cell sap will certainly be needed in many cases if an accurate result is desired. In conclusion I would call attention to the importance of this discovery in respect to one of the most prominent biological problems, the question whether salts are able to penetrate the protoplasm or not. F ar-reaching conclusions have been drawn from the fact that when a cell is placed in a solution of a certain substance the protoplasm contracts and does not subse- quently expand if left in contact with the solution. This has been inter- preted to mean that the substance in solution is unable to penetrate the protoplasm. I find, however, in many cases, that the true interpretation 18 exactly the opposite. The permanent contraction of the protoplasm is caused by the penetration of the substance in question which produces chemi- cal effects upon the protoplasm, wholly different from those produced by a substance whose action is purely osmotic. In view of this we cannot give credence to certain very important con- clusions and theoretical considerations which have been based on this criterion of penetrability. These points will receive fuller discussion in a subsequent paper.—W. J. V. OsteRHout, University of California. * The expression chemical action is here used in a very broad sense to include effects which are not osmotic in character. CURRENT LITERATURE BOOK REVIEWS The origin of a land flora Under this title Professor Bower has written a volume which must be regarded as the culmination of his important studies during the last twenty years. It is a formal and amplified statement of the views advanced in his series of five papers entitled “Studies in the morphology of spore-producing members,” published between 1894 and 1903. The scope of the volume is very broad and its spirit is admirable. The author recognizes that his thesis is not proved; that in the very nature of the case it never can be; and that there are many possible alternatives. However, he presents so strong a case that the truth of the theory would not come to anyone as a surprise. Naturally the book is speculative, and the author’s frequent insis- tence that this is the case should be respected by those who follow its doctrine. The human mind seems to be so constituted that when a view is distinctly formu- lated it thereby seems to gain additional proof. There is a strong tincture of teleology at every turn, the elimination of which would have strengthened the discussion. This gives it a flavor of unreal ‘“‘other- worldliness” that is becoming unscientific. That a certain structure would be useful to a plant and therefore it grows, is hardly acceptable as an explanation of origins. The thesis of the volume is the origin of the sporophyte as an antithetic genet ation, which has become fixed and amplified by the invasion of the land. s developing this doctrine, the author presents first a statement of the working hypothesis (pp. 254), then a detailed statement of facts (pp. 403), and finally the gen- eral comparisons and conclusions (pp. 60). In a brief review it is impossible to present the suggestions that fill these three parts. The second part—the statement of facts—is wisely separated from the other two, and in this form it represents . admirable treatment of the morphology of bryophytes and pteridophytes, epee ally the latter. Much new material is included here, and especially helpful 1 - € massing of the morphological, anatomical, and paleobotanical evidence These three points of view are too often kept separate, when they should serve as checks upon one another. The two theoretical parts also contain much more detail than can be presented. However, the broad outlines of the working hypothesis and some of the more important conclusions may be indicated. Bower, F. O., The origin of a land flora: a theory based upon the facts ie: alternation. 8yo, PP- xii+727. figs. 361. London: Macmillan and Co. 1908. $5-59 56 ; 1908] CURRENT LITERATURE 57 Running throughout the hypothesis is the assumption that the most critical and hence controlling fact in the life of any organism is the relation existing between environment and fertilization. Perhaps the most fundamental con- ception is that the “‘Archegoniatae” are amphibious. (It may not be out of place here to suggest that the group name ‘“‘Archegoniatae” has about outlived its usefulness. To associate the widely separated bryophytes and pteridophytes in this way, and to include or exclude part of the gymnosperms, is a grouping too unnatural and misleading to be continued.) That the gametophyte of “Archegoniatae” is amphibious means that it is just as aquatic as an alga, and shows this in its delicate structure, lack of intercellular spaces, lack of a water- conducting system, and the possibility of fertilization only in the presence of water. ‘The gametophyte proclaims its ultimate dependence on external fluid water as thoroughly as an alga.’’ On the other hand, the sporophyte is char- acteristically an aerial body, with its more robust habit, ‘‘ventilating”’ system, vascular strands, and spores adapted for dryness. Attention is called to the fact that the ‘‘Archegoniatae”’ retain with remark- able pertinacity this “awkward and embarrassing” method of fertilization; but that with the advent of the seed plants this becomes modified, and the higher seed plants at last become completely terrestrial. A general outline of the steps by which the sporophyte was established and amplified as a terrestrial structure may be stated as follows: The gametophyte was the previously existing phase, and the initial step in the appearance of the sporophyte was the “‘post-sexual divisions, giving rise to a plurality of germs,” such as is observed in the life-histories of certain green algae. In plants exposed to changing conditions of moisture and drought the fixing of such a generation would be assured, according to the following logic: external water would be occa- sional rather than constant; hence the sexual act would be occasional; hence there would be less dependence upon the sexual act for multiplying individuals; hence a “premium would be put upon” the other method of propagation suit- = for drier conditions. Thus the sporophyte is to be rec gnized as a body originating as an adaptation to terrestrial life. In amplifying the sporophyte, it is assumed that the first and also the final office of the sporophyte is to produce spores, and that the larger the number of spores (in homosporous forms) the better the chance of survival; therefore the increase in number of spores is ‘‘encouraged.” But to protect spores when A and to nourish them during development presupposes some vegetative em. The process for developing this vegetative system is the familiar theory of Progressive sterilization, so well traced by the author among bryophytes. Among Tyophytes, however, there are certain limits imposed by mechanical and physi- ological conditions; while among vascular plants there is greater freedom for Progress, chiefly by the segregation of the sporog ee and the formation of ‘‘appendicular organs.” As a result of this progressive Sterilization and n g £48 fc Meet as the fertile tissue appears later and o 58 BOTANICAL GAZETTE [JULY later in ontogeny, until what was first in phylogeny comes to be last in ontogeny. This disposition of the recapitulation theory appears in various places throughout the volume, and it is evident that the author regards it as reliable only within certain limits, when it agrees with other evidence. From among the general conclusions the following may be selected as of most general interest. The author concludes that no definite algal form now living can be held to have been a direct progenitor of any known archegoniate type; but that certain algae suggest in their post-sexual phase how the initiation of the sporophyte may have occurred. Also the liverworts and mosses may be held to be “blind branches of descent;” but they illustrate changes that suggest the origin of sterile tissues from those potentially fertile, and the final establishment of a self-nourishing system in the sporophyte. ; The gametophyte of early pteridophytes was probably a relatively massive green structure, with deeply sunk sexual organs; and the sporophyte was the strobiloid type of body illustrated by Lycopodium Selago and its allies (the author's well-known “theory of the strobilus”). This reconstruction of the most prim tive vascular body is obtained by converging all’the known pteridophyte lines, and the result is a body which arose from no one knows what, but which does not suggest any known bryophyte or alga. : This is a very meager outline of the contents of a large volume, crowded with facts and suggestions. Such speculation brings perspective and stimulus, and its only danger is a confusion of theory with fact, for which the author in this case could not be held responsible. Perhaps the most serious charge that could be brought against him, in this connection, is his great command of picturesque statements, which are highly figurative but contain perilous suggestions for the unwary. For example, that “encouragement was given” to a multiplication of spores; that the method of fertilization in archegoniates is “awkward and em barrassing;” that “‘a premium was put upon” aerial spores, etc., are extremely | telling forms of statement, but they are more rhetorical than exact, suggesting far more than was intended. ; At all events, the volume is a monument to the research power and philo- sophical insight of its distinguished author.—J. M. C. Electro-physiology _ Two years ago plant physiologists were rather taken aback by a large volume | of researches on plant response from the pen of a contributor previously aes in this field. It is not often that so brilliant a display marks the advent of aneW scientific luminary, and it was impossible at once to determine whether he ws meteor, whose light would flash and disappear, or a star of the first magnitue® — There were not wanting, indeed, signs that he was erratic. This work? conspicu: ously lacked relation to the present state of knowledge and showed scant acquaint el Ee J. C., Plant response as a means of physiological investigation. Se ea review in BOTANICAL GAZETTE 42:148. 1906. a 1908] CURRENT LITERATURE 59 ance with the researches of others; while the naiveté with which some of the t lite problems ttacked and dismissed as solved awakened amused incredulity. At the same time the author’s ingenuity in devising and adapting self-registering methods to the mechanical and electrical responses of plants, as well as the suggestiveness of some of his results, made the book possibly an epochal one, since it struck out a rather new path for most important investigations. So far, however, nothing has come of it. Its reception has been apathetic, not to say cold, and to all appearances it has fallen dead because of its faults and _ in spite of its manifest virtues. No researches have followed it up; no investi- gator has used its methods. That volume on Plant response was the second of a series of three (the first on Response in the living and non-living), of which the third has just made its appearance under the title Comparative electro- physiology.s The author herein shows the same peculiarities as in the preceding volume. There is the same naive interest in well-known phenomena, as though they were quite novel; there is the same lack of effort to connect his work with that of others, so far, at least, as citing their researches or results is concerned. It is doubtful if in this book of over 800 pages, dealing with a very special topic on which there must be a legion of workers, there are a dozen citations of original Sources. There is much repetition of the earlier volume; the same tilting at windmills—vigorous attacks on vitalism and on the contrast between animals and plants, and between “sensitive plants” and others, till one is tempted to inquire with Sairey Gamp, “‘Who denyges of it, Betsey, who denyges of it?” This volume maintains the same simple thesis as its predecessor—as simple as the faith of Islam, ‘Allah is great and Muhamed is his prophet” —contraction is universal and negativity is its sign, The direct response to every stimulus is _ Contraction,” the indirect one (at a little distance) is “expansion.” The former Is said to be accompanied by reduction and the latter by increase of turgidity, with corresponding electric variations. The expression of contraction in movement, Suction” (ascent of sap), growth, “‘torsion” (in climbing plants), death, and electric variation, constitutes the theme of the two volumes. This much needs to be said: There are reasons for expecting Some universal fundamental reaction in all responses; it may be that Bosk has hit upon it in what he miscalls “‘con- ion” (for this is really nothing but a reduction in turgidity); but his work is not g convincing. This book shares with its predecessor, also, the confusion between energy and stimulus, a confusion that is possible because we know so little of plant — ®nergetics. This reaches its absurd climax in the conception of the author as to si function of plant nerve. He gravely tells us that the ramification of the nerves” in a leaf provides a “virtual catchment basin for the reception of stimu- lus,” whence it is transmitted to the body of the plant, there to be stored and Wise 8 * Bose, J. C., Comparative electro-physiology, a physico-physiological study. Yo. pp. xliv+760. jigs. 406. New York: Longmans, Green & Co. 1908. $5.75. 60 BOTANICAL GAZETTE [JULY used later in responses. All this is quite apart from the question of the energy fixed in photosynthesis. This suggests another fault. Bosr seems to ignore, if he is not ignorant of, the anatomy of the parts with which he is dealing. Skin is skin, whether it be the skin of plant or animal. Stomach of Gecko and pitcher of Nepenthes (an open stomach of a primitive type, he calls it) are all one to him; they behave alike, in spite of their extraordinary differences of structure. Nerves of animal and nerves of plants, which have been identified by their behavior as the vascular bundles of plants, are physiologically the same. Digestion being a “‘diphasic process,” that is, consisting of secretion first and absorption afterward, roots, which secrete substances that dissolve their mineral ‘‘food” and then absorb it, must be another kind of open stomach; and besides, they behave electrically as stomachs do! Now if these things are so, it argues that the responses with which Bose is dealing are either extremely superficial or extremely fundamental, inhering in all living matter; and in either case they would be of little significance. The situation seems to be most peculiar. Bosr, we judge, is a brilliant experimentalist, trained first as a physicist, but inadequately equipped with knowledge of what has been done in the field of plant irritability. This has been at once an advantage and a snare. It has left him free to present his researches untrammeled by the conventional view, but it has exposed him to mistakes which a little more knowledge would have avoided. It has given him courage to attack the most knotty problems, but it has led him to satisfaction with inadequate conclusions, Apparently, too, he has become possessed by a theory as to the nature of response, and under the yoke of that theory he makes all his captive facts to pass. Out of these books we look for some one to rescue many good observations, now apparently gone awry; and by his methods and apparatus in the hands of real physiologists we hope soon to see made important advances in the knowledge of Reizphysiologie—C. R. B. Conference on Genetics The report* of the Third International Conference on Genetics held under the auspices of the Royal Horticultural Society, July 30 to August 3, 1906, is 4 veritable treasure-trove for students of heredity, hybridization, and plant-breed- ing, both in their theoretical and practical aspects. Besides giving a minute account of the doings of the Conference, there is a brief but excellent sketch by the secretary, Rev. W. Wixxs, of the life and work of GREGOR MENDEL, illustra by three good portraits, a fine view of the Abbey at Briinn, and a facsimile letter written to NAGEL. Excellent portraits are also given of some of the mor _ 4 Report of the Third International Conference, 1906, on Genetics; bybridiza- tion (the cross-breeding of genera or species), the cross-breeding of varieties, and general plant-breeding. Edited by the Rev. W. Wrixs. 8vo. pp. 496. figs. Igh se London, 1907. : 1908] CURRENT LITERATURE 61 prominent participants in the Conference, as LAWRENCE, WILKS, BATESON, JOHANNSEN, TsCHERMAK, WitTmMAcK, Hurst, Miss SAUNDERS, and the VIL- MORIN brothers. Besides the address of the chairman, Prof. BATESON, upon ‘‘The progress of genetic research,” there are a number of important contributions to Mendelian inheritance, by Hurst, DARBISHIRE, DAVENPORT, Miss SAUNDERS, TSCHERMAK, and BIrFEN; two papers upon orchid hybrids by RotFE, and CrawsHay; and several papers upon the occurrence of natural hybrids, the most comprehensive of which by E. G. Camus is not printed in full because it was sufficiently volumi- nous to make a separate book. This paper deals with the spontaneous hybrids of the European flora. A lengthy list of natural hybrids is also given by LyNcu, Curator of the Botanic Garden, Cambridge. PrirzER deals briefly with hybridi- zation and the systematic arrangement of orchids, and a valuable posthumous paper by the same author discusses the probability of the origin of the Orchida- ceae from the Amaryllidaceae. OsTENFELD describes some castration experi- ments with Hieracium, and RosENBERG reports briefly his work upon the cytology of Drosera, and also on Hieracium hybrids. In some of the latter he has found considerable differences in the number of chromosomes carried by different eggs of the same plant. Bunyarp reviews the question of xenia, stating that after an extensive search for evidence of this phenomenon he knows of but a single instance, this being an apple cross made by him (‘‘Sandringham” X Bismarck”). J. H. Witson describes a considerable number of infertile hybrids, which he has studied with some care. Dealing with plant breeding from the more practical point of view are the following: E. F. Sure outlines the plant-breeding operations of the U. S. Department of Agriculture; the improvement of sugar cane is discussed at length y Sir DanteL Morris; papers by Zavitz, P. DE ViLmorIN, C. E. SAUNDERS, and BrrFEN describe results in breeding improved races of wheat and other small grains; HANSEN tells of his work in breeding cold-resistant fruits; RIVERS and Laxton also give some of their results in hybridizing fruits, particularly peach X nectarines, apple hybrids, and plum hybrids; Laxton draws some conclusions from the work with peas for which his family is justly famous; WarD gives a finely illustrated description of some of his excellent work on carnations, explaining among other things his method of keeping pedigree records; VAN TUBERGEN, of Haarlem, discusses hybrids among bulbous plants; Paut gives the derivation of a number of fine hybrid roses of recent production; H. H. GROFF, the specialist in Gladiolus, discusses plant-breeding from the point of view gained by work with these plants, and emphasizes the idea that the plant-breeder has much to learn from the animal-breeder. ‘There are several shorter papers by other authors. _ Many of the articles are illustrated with fine halftones and the press work Sup to the high standard for which the reports of the Royal Horticultural Society are well known.—Grorcr H. SHULL. 62 BOTANICAL GAZETTE [JULY North American trees Three years ago this journals noticed the appearance of SARGENT’s excellent Manual of the trees of North America, which brings into a convenient volume the information that is much more elaborated in his great Silva. Now another manual of the trees has appeared, bearing the title North American trees, and written by Britton and SHAFER.® The very handsome volume is made bulky by the heavy paper, so that it will have to be used more as a standard dictionary than as a handy manual. The distinct mission of the volume, however, is to present the trees in language so free from technical terminology, and by illustrations so characteristic, that they may be recognized by ‘“‘any person of ordinary information.”’ This will certainly meet and stimulate the growing interest in trees, a purpose that is worth while. The authors are in an exceptionally favorable position to make such a book accurate rather than merely popular, and it is a good thing now and then for men — who have the facts to give to the public something that can be relied upon. The identification of trees should now be as easy as the long popular identification of birds. The characters are drawn from foliage, flowers, and fruit, and they are pre- — sented in the free style of ordinary description, rather than in the compact style of taxonomy. The illustrations are from excellent sketches and photographs, and really illustrate. The economic value of the various trees is included, so that when the name of a tree is discovered, the inquirer is in a position to obtain much useful and interesting information concerning it. Of course any definition of a tree must be arbitrary, but the authors have liberally included all species known to become trees in habit (with “single erect stem or trunk ”), even if they are almost always shrubs.—J. M. C. MINOR NOTICES Physiology of stomata.—Ltovp has given us a careful study of the behavior of the stomata in two desert plants, Fouguieria splendens and Verbena ciliata, made at the Desert Botanical Laboratory of the Carnegie Institution.’ He addressed himself particularly to the question of the regulation of transpiration — by stomatal movements, and furnishes conclusive evidence that the stomata it these plants, where there are no complications in the way of pits, plugs, or other contrivances, are not able to adjust the transpiration to the “‘needs” of the plants. Wide variation in the rate of transpiration is found, quite independent of the S 5 Bot. GAzETTE 392301. Ig05. 6 BRITTON, NATHANIEL Lorp, and SHareR, JOHN ApotpH, North American 3 — being descriptions and illustrations of the trees growing independently of cult vation in North America, north of Mexico and the West Indies. Imp. 8vo. pp- * + 894. figs. 781. New York: Henry Holt and Company. 1908. .00. ‘ 7 Luoyp, F. E., The physiology of stomata. Imp. 8vo. pp. 142. pls. 14. Ags 3% Washington: The Carnegie Institution, Publication 82. 1908. a 1908] CURRENT LITERATURE 63 position of the guard cells, the maximum diffusion capacity of the pore being seldom (if ever) utilized. A rhythmic variation in the transpiration rate was found to be independent of the stomatal rhythm. As to the latter, Luoyp finds that, aside from the indirect effect of high relative humidity in reducing the water loss and so favoring the opening of the stomata, there is no relation between the humidity and the position of the guard cells. He finds no closure of the stomata in anticipation of wilting, but during wilting a slow closure, without the prelimi- nary opening attributed to them by Francis DARWIN. Lioyp also attacked an interesting problem in the supposed photosynthetic activity of the guard cells. He finds evidence of amyloplastic but none of chloro- plastic activity, and concludes that the movements of the guard cells are related to their accumulation and dissolution of starch derived from the chlorenchyma, rather than to any photosynthetic products of the guard cells themselves. This is a careful and thorough piece of work, highly creditable to the labora- tory from which it comes. The experimental evidence is now at hand supporting conclusions which have been held by some physiologists for some years as highly Probable on purely physical grounds.—C. R. B. The timbers of commerce.—A second edition of BOULGER’S Wood, revised and enlarged, has appeared.* It deals with 1ooo kinds of wood, and includes Most of those known in general commerce. The first part (pp. 121) discusses wood in general, under such topics as origin, structure, development, classifi- cation, defects, selection, uses, supplies, and tests. The second part presents the woods of commerce, giving in each case the source, character, and use. The 48 Plates are from photomicrographs of sections, and are intended to show the dis- tinctive microscopic features. Such a book is encyclopedic, and therefore for Its purpose it is extremely useful. The demand for a second edition speaks well for the favorable reception of the first—J. M. C. Knuth’s Handbook.—The second volume of Davis’ English translation of this encyclopedic work has just been issued by the Clarendon Press.? The original volumes and the first volume of the translation were reviewed in this journal,*° so that the general scope and character of the work have been noted. The pres- ent volume includes observations on flower pollination made in Europe and In the arctic Tegions, and is a great mass of observations upon species ranging through the natural orders, from “Ranunculaceae to Stylidieae.” Such a book “annot be reviewed, for it is an encyclopedia. It can only be announced, and PRC cee ET _ * Bourcer, G.S., Wood, a manual of the natural history and industrial applica- tions of the timbers of commerce. 8vo. pp. xi+ 348. pls. 48. London: pais Amold. 1908. $4.20. é ° Knuru, Paut, Handbook of flower pollination. Translated by J. R. Arvs- °rtH Davis. Volume II. 8vo. pp: viii+ 703. figs. 210. Oxford: Clarendon Press. Half morocco 35s.; cloth 31s. 6d. *° Bor, GAZETTE 28: 280. 1899; 28:432. 1899; 422494. 1906. : 64 BOTANICAL GAZETTE [JULY this translation should greatly stimulate observation in a field too much neglected | by American botanists.—J. M. C | Flora of Manchucia.—Komarov"' has completed his Flora of Manchuria with the appearance of the second part of the third volume. The whole work con- tains 853 pages, and the last part includes the Sympetalae from Labiatae to Com- positae. It is interesting to note that in presenting 18 families, 130 genera, and 336 species, only two new species are described—one a Scutellaria, the other a Saussurea. An appendix contains descriptions of two new species of Anemone. In this part much the largest families are Compositae (164 spp.), Labiatae (48 — spp.), and Scrophulariaceae (43 spp.)—J. M. C. Grasses ot Louisiana.—R. S. Cocks,'? Tulane University, has published a list of the grasses of Louisiana, based upon collections made during each season — since 1897. The catalogue contains 290 species, which is said to represent 12 per cent. of the flora of the state. It is interesting to note that 11 species are known to find their northern limit in Louisiana; 9 species their southern limit; — Io species their western limit; and 10 species their eastern limit; while 5 species — are given as occurring only in Louisiana so far as the United States is concerned. — fp” GP The western willows.—JonEs*s has published an account of the western Salica- cea, recognizing 53 species of Salix, with numerous varieties, and 8 species te Populus. The species have been studied in the field and the descriptions are compact and clear; so that the willows are presented as they actually appear 2 nature. A key to the species makes their recognition very direct, and the chat — acters used are very obvious ones. Willows have been difficult to identify, and ; this presentation should be of much service.—J. M. C. | North American Flora.—The second part of Volume IX concludes Poly- e poraceae, by W. A. Morritt, 32 genera being presented, 16 of which have recently = been described by the author. In various genera 36 new species are described.— _ J. a NOTES FOR STUDENTS aie Biometrical studies.—The close interrelation between fluctuations and the environment, especially those factors of the environment which in any way i nutrition, has been recognized by many authors and overlooked or ignored by others. Several valuable contributions have been made to this subject. Inte *t Komarov, V., Flora Manchuriae. Acta Hort. Petrop. 257:335-853- pls. 46. : 1907. e is Cocks, R. S., Annotated catalogue of grasses growing without cultivation . Louisiana. Bull. 10. Gulf Biologic Station, Cameron, La. 3 JoNEs, Marcus E., The willow family of the Great Plateau. pp- 32: Salt Lake City, Utah. 1908] CURRENT LITERATURE 65 paper read before the third Flemish Natural History Congress at Antwerp in 1899, MacLrop" shows that in Centaurea Cyanus the mean numbers of rays and disk-florets are highest in heads which bloom earliest and that they fall continually as the flowering season progresses, the change in disk-florets being the greater. When individuals are considered, the terminal heads have the highest numbers, and each successive bud-generation has a less number than the preceding. Three series of cultures under different conditions of soil led to the conclusion that the first heads of each plant behave like the terminal heads of well-nourished plants; and that the last heads of each plant and of the season resemble the terminal heads of poorly nourished plants. There is no indication in this species that the Fibonacci numbers tend to predominate. This paper is not listed in DAVENPoRT’s rather comprehensive bibliography, and was unfortu- nately unknown to me when I was investigating the seasonal variability in Aster prenanthoides. The conclusions reached for Centaurea are the same as those reached by me about a year later in Aster. More recently MacLeop and BurvenicH'S have made an experimental study of the variability in the number of rays of Chrysanthemum carinatum and find essentially the same condition as in Centaurea, except that, unlike that species, Chrysanthemum carinatum shows the modes on the Fibonacci numbers, and as the mean number changes with the change of nutrition, the prominence of one mode is lessened as the neighboring one increases. The variation goes by steps or leaps from one favored value to the next. In discussing these “‘variation- steps” (Varietietrappen), three types of behavior are recognized: first, that in Ww ich the modes, whether one or several, agree with the terms of the relevant series, €. g., Chrysanthemum carinatum, 13 and 21; second, that in which the number of parts is constant or but very slightly variable and the values are those of the terms of the series, e. g., Senecio Jacobaea, 13, S. nemorensis, 5, S. nemorensis octoglossus, 8, etc.; third, the condition found in Centaurea Cyanus and in Aster in Which the mode may fall upon any of the values lying between the terms of the series and in which as the mean values rise or fall the mode passes gradually through all the successive values. Seven variation-scales or series are recog- nized as fully demonstrated for one or more plant-characters; viz., (1) the Fibo-— nace series, 3, 5, 8, 13, 21, 34; (2) 5, 10, 15, 20 (carpels of Geranium); (3) 3, ®, 7 (leaflets of Trifolium); (4) 3, 6, 9 (flowers of Lonicera); (5) 2, 5, 8, 11 (flowers of Cardamine pratense); (6) 4, 8, 12, 16 (flowers of Cornus mas); (7) 4, 8, > 32, 64 (peristome of mosses). The author gives a lucid explanation of the Cause for the existence of such series by referring them back to the period in a wines MacLrop, J., Over de veranderlijkeid van het aantal randbloemen en het ‘tal schijfbloemen bij de korenbloem (Centaurea Cyanus) en over correlatiever- Schijnselen. Bo tanisch Jaarboek 12: 40-74. 1900 1 op 5 MacLeon, J., and BuRVENICcH, J. V., Over den invloed der levensvoorwaarden Cree achat bij Chrysanthemum carinatum en over de trappen der tlijkheid. Botanisch Jaarboek 12:77-170. 1907. — 66 BOTANICAL GAZETTE [JULY development when a single additional cell-division will determine the leap from one stage tothenext. The causes which incite cell-division may proceed gradually and continually but not until they have increased to a certain required degree will the additional cell-division take place, so that the effect is more or less dis- continuous, though the combination of causes may be continuous. It is also shown by MacLeop in the paper just i d by De BRUYKER,”® both working with Chrysanthemum carinatum, that the usual rule, according to which the earliest heads have the highest numbers, may be reversed by increasing the nutrition after the earliest heads are blocked out, thus fully demonstrating that the normal change which takes place from the beginning to the end of the flowering season is dependent upon the regular decline in the nutritional condi- tions. This seasonal periodicity is strongly emphasized in another paper by Dr BruYKER."? He finds that the number of flowers in the umbels of Primul elatior follows the same law of seasonal change as that followed by Centaurea, — Aster, and Chrysanthemum above mentioned, and now known to hold fora number of species. Specimens of Primula growing in dry places had a lowet mean number of flowers in the umbels than plants growing in moister places. The variation-curves for this character differ under different conditions and at different times, but always display modes on the Fibonacci numbers, 3, 5, 8,an¢ 13. Evidence is given to show that these multimodal curves are not due to the presence of heterogeneity in the race, but are referable to the fact that develop- ment proceeds by more or less discontinuous stages, whose value in any particular instance depends upon the external and internal environment. : The complete dependence of the values of fluctuating characters upon the environment has also been well shown by KiEss'® in a comprehensive investi- gation of variation in the floral organs of Sedum spectabile. To avoid the posst — bility of dealing with mixed races, KiEBs has confined his studies to groups of individuals formed by taking cuttings from a single original plant. Growing these in several different habitats, he finds that for the stamens there isa different type of variation-curve in each habitat, which remains fairly constant so long ® — the habitat remains unchanged. Stamens of Sedum show the first of MacLeoo’s < three types of behavior, with 5 and ro as the favored classes. The various habitats produce curves ran ing from a monomodal curve with 5 as the mode and with very slight variability, through a bimodal curve with different relative values of modes § and 10, to monomodal curves with ro as the mode. Tt is show? E © De BruyKer, C., De gevoelige periode van den invloed der voeding OP br a aantal randbloemen van het eindhoofdje bij Chrysanthemum carinatum. rode Vlaamsch Nat. u. Gen. Cong,, Brugge, S. 1906. pp. 6. ‘7, De polymorphe variatiecurve van het aantal bloemen bij Print elatior Jacq.; hare beteekenis en hare beinvloeding door uitwedige factoren. ‘aap e Vlaamsch Nat. u. Gen. Cong., Brugge, S. 1906. pp. 29. figs. 2. J "SK ers, G., Studien iiber Variation. Roux’s Arch. 24:29-113- A8% eo y. 1907. : 1908] CURRENT LITERATURE 67 that not only variability itself, but the nature of the variation-curve and all of its “constants” are the product of the environment, and are a measure of the uni- formity or lack of uniformity of envi tal conditions. He concludes that there isno such thing as absolutely constant characters, and that the most constant may become quite variable under special conditions. There is no real distinction be- tween continuous and discontinuous variability, if the question of heredity is left out of account, as both of these as well as transitions between them may be induced by changes of the environment. The applicability of QUETELET’s law, which seems to indicate that variability is due to chance, depends upon the fact that the differ- ent values of the variable characters are determined by the coordinate action of several independently variable environmental factors. In an attempt to analyze the effective factors in the environment it is shown that the values of variable characters of Sedum increase directly as the quantity of carbohydrates increases and inversely as the quantities of available water and of salts increase. Chemical analysis of plants grown in the different habitats are presented in support of this W. PEARL" has studied the variability of Chilomonas paramecium and Parame- cum caudatum living under favorable and unfavorable conditions. He finds that the types of the two populations are significantly different, that of the less favored culture being smaller and relatively more slender. The variability was the same in the two cultures; but the curve of the well-fed culture was positively skew, while the poorly fed presented a nearly normal variation-curve. There is a correlation of 0.6 between length and thickness, and also a significant correlation tween size and form, which is recognized as opposing DrrescH’s statement that proportionality is absolutely independent of size. In Paramecium, PEARL?° also finds that there is a high degree of correlation or ‘“‘assortative mating” be- tween the two members of a pair of conjugating Paramecium, the coefficient Hs from 0.43 to °.79 in respect to length, and 0.217 to 0.349 in respect to readth. : the length. It is also found that the conjugants are differentiated as a c from the non-conjugating population, the former being smaller and less variable. From this the author concludes that conjugation tends to restrict rather than imctease variability, and that the conjugant type bears much the same relation to 7 hon-conjugants as that borne by the germ-cells of a metazoan to its soma. ” evolutionary progress must rest upon changes in the conjugant type. Of interest for the purely methodological side of biometry is a brief paper tio "9 Peart, R., Variation in Chilomonas under favorable and unfavorable condi- ms. $233-72. figs. 7. O. 1906. : *° Peart, R., A biometrical study of conjugation in Paramecium. Biometrika 5213-297. figs. 9. F, 1907. 68 BOTANICAL GAZETTE [JULY by De BRUYKER,”' in which it is shown that the means and quartiles, and indeed all the ordinates, of the ogive, when calculated according to the methods of GAL- — TON, are a half-unit too low, due to the fact that GALTON constructs his curve — on the extremity of the classes instead of on their mid-values. The suggested correction brings a very close agreement between the median and the arithmeti mean. DARBISHIRE?? gives an interesting popular discussion of correlation of the kind dealt with by biometers, using as his basis the dice-throwing experiment of WELDON, in which the relation between two successive throws of dice are the correlated quantities considered, when a certain number of dice from the first throw are left on the table to influence the result of the second. When none of the dice are left, the two throws are totally unrelated and the correlation is zero; and when all are left, so that the second entry is an exact repetition of the first, correlation is complete. Tables are given showing the actual results of throwing 12 dice in this way under every possible condition-as to the number of — dice left back to influence the second throw, thus beautifully illustrating the different degrees of correlation between zero and unity — GrorcE H. SHULL. Symbiosis.—A recent paper by KEEBLE of Reading and GAMBLE of Man- chester, England, continues the investigations of these two naturalists into the subject of the symbiosis of plants and animals.?3 Of late years these two men have been almost the only ones continuing this study, which, as the literature shows, was being actively pursued fifteen or more years ago. Convoluta roskoffensis is a simple flat-worm living between the tide-marks on the northern coasts of Europe. It is usually green, owing to the presence in its tissue of chlorophyll-containing cells, which have been diagnosed as one of the Chlamydomonadeae. They resemble the members of the genus Carteria, but for certain reason KEEBLE, the botanical collaborator, hesitates to place them positively in this genus. The life-history of both components of the association — been worked out. From this study it is clear that the flat-worm begins ie existence free from green cells. There is no transmission of green cells or evenof rudimentary cl topl (plastids) from parent toegg. The green cellsappeat to be chemotactically attracted to the eggs and egg-cases. Pure cultures of ge alga may often be obtained from egg-cases which have attracted and become — partly filled with the green motile cells. By carefully washing in sea-water fre from the alga, colorless Convolutas can also be obtained. These will remail colorless or will turn green according to subsequent treatment. If kept in S@ 2t DE BRUYKER, C., Bemerkingen aangaande de Galton’sche curve. Han@ : tode Vlaamsch Nat. u. Gen. Cong., S. 1906. pp. 6. figs. 2. . 22 DARBISHIRE, A. D., Some tables for for illustrating statistical correlate Mem. and Proc. Manchester Lit. and Phil. Soc. 5I:no. 16. pp. 21. diagrams 12. 7 ©” pl. 28 Je 1907. : *3 KEEBLE AND GAMBLE, The origin and nature of the green cells of Conv : roskoffensis. Quart. Jour. Micros. Sci. 51:167-219. pls. 13, 14. 1907- 1908] CURRENT LITERATURE © Eg water passed through a Pasteur-Chamberland filter, they will remain colorless; if kept in such filtered water to which a loopful of a pure culture of the alga has been added, they will turn green as completely as if they were kept in unfiltered sea-water. Apparently the young animals cannot be infected by cells removed from the bodies of older green Convolutas. : The green cells are reported to undergo degeneration in the tissues of the animal, especially as regards their nuclei, and to this is attributed the inability of the green cells to maintain an independent existence, or to thrive in cultures, or to infect young Convolutas, when removed from the bodies of older green ones. ether under suitable conditions of culture, the algal cells may be able to complete themselves, to restore or to regenerate the deficient nucleus, to become rejuvenated, is not determined by these experiments. The functions of the alga in the body of its host have been experimentally studied. The authors conclude that the alga, photosynthesizing sugar, is os- motically relieved of a considerable portion of this food. It must diffuse, if it remain unchanged, to adjacent cells containing less; but if the sugar be converted into starch,the animal cannot digest and absorb it so long as the algal cells them- selves live. Soon after infection with the alga, the animal ceases to excrete its nitrogenous wastes, and these, absorbed by the alga, are converted by it into higher organic compounds, into nitrogenous foods. As many of these as are soluble also diffuse into adjacent animal cells. At this stage it would appear that both animal and plant profit by their association, the animal gaining a supply of sugar and of soluble nitrogenous food, the plant obtaining a steady supply of partly elaborated organic nitrogenous food-material. Later on, however, the animal ceases to ingest solid food, and there being no other source of nitrogenous food than the algal cells themselves, the animal proceeds to devour em in its own tissue. Thus it destroys its source of food and ultimately itself, but before this it breeds. is association, therefore, is similar to that of fungus and alga in lichens, where the fungus component, incapable of photosynthesis, is forced to obtain hon-nitrogenous food, saprophytically or parasitically. The excreta of the de- Pendent component may manure the green plants, but if they do, the benefit 'S a dubious one, since it leads to destruction without issue. A word may well be added to commend the ingenuity of the experiments, the care and thoroughness with which they seem to have been carried out, and the Pages with which inferences have been drawn from them and stated.—G. J. CE. : Plant diseases.—A root disease of sugar cane, first described from Java in 1895 a WAKKER is the subject of a bulletin by Futton.*4 It is characterized by canes reduced size and weight, and by reduced leaf system. A large percentage of ** Futton, H. R., The root disease of sugar cane. Bull. 100, La. Agric. Exp. Sta. Jan. 1908, 79 BOTANICAL GAZETTE [JULY affected stalks die. These effects are traceable to deficiency in the root system. — The lower leaf sheaths of affected canes do not fall away as they normally do, ut remain cemented together by the whitish mycelium of a fungus, Marasmius plicatus, which occurs saprophytically upon decaying vegetable matter, and is also able to attack living tissues of low vigor and thus to become a parasite. The — conditions favoring attack are summarized as follows: ‘‘Slowness of germina- tion and early growth; improper cultural procedures; unsuitable soil; bad drain- age; unfavorable seasonal conditions; the stubble crop.’ Preventive measures are: ‘‘careful cultivation; selection and disinfection of seed cane; resistant varieties; destruction of infected trash; resting land from cane.” A second bulletin by the same author treats diseases of pepper and beans.?5 He mentions a wilt of pepper caused by a non-sporing sclerotial fungus; the beam — anthracnose due to Colletotrichum lindemuthianum,; the bacterial blight due to s onas Phaseoli; and a disease caused by Rhizoctonia. : Eustacr”® has been experimenting on fruit rots. Tests were made of the — ability of fungi to produce decay in cold storage. On March g several varieties of apples were inoculated with bitter rot (Glomerella rufomaculans), black rot (Sphaeropsis malorum), blue mold (Penicillium glaucum), brown rot (Sclerotima fructigena), pink rot (Cephalotheciwm roseum), and Alternaria. ‘The fruit was then placed in cold storage at a temperature of 31° F. When removed and && — amined on May 9, it was found that the only fungus which had caused decay was Penicillium glaucum. When removed to warmer temperature, all the other species developed and caused decay. Decay was not entirely prevented by4 — temperature from 35 to 56° F., and decay proceeded rapidly at a temperature of 48° to 69° F. Sclerotinia fructigena on the peach developed decay slightly in two weeks at a temperature of 32° F., when inoculated by puncture. Fruits inoc ay by contact merely showed no decay at the end of two weeks under these condi- tions. Experiments were made to determine whether sulfur fumigation (I 02. of sulfur to 25 cubic feet of space) would kill the spores of rot producing fungus It was found that the spores of Penicillium glaucum can be killed this way, but 3 that injury is caused to the apples themselves by the sulfur fumes. Carel) — notes were made concerning the development of apple scab, and it was asc tained that the scab of the apple can increase even when the scab in questio= i. is completely covered with a coating of the Bordeaux mixture. a Apple leaf spots have long perplexed the plant pathologist. One of them has at last been definitely proved to be caused by Sphaeropsis malorum.”’. ™ disease in question is characterized by circular or irregular reddish-brown 25 FULTON, H. R., Diseases of pepper and beans. Bull. ror, La. Agric. Expet- e Sta. Jan. 1908, : *° Eustace, H. J., Investigations on some fruit diseases. Bull. 297, N. ¥- ABH Exp. Station, Geneva, N. Y. Feb. 1908, 27 Scort, W. M., and Rorer, J.B., Apple leaf spot caused by Sphaeropsis malor U.S. Dept. Agric., Bur, Plant, Ind. Bull. r21, part 5. March 1908. es 1908] CURRENT LITERATURE 7. with slightly raised purplish margins, which attain a diameter of 3.5 to 13™™. The mature spots are usually circular, but may become irregular. This disease has been variously attributed to Phyllosticta, Coniothyrium, and other causes. The present authors obtained pure cultures of S phaeropsis malorum from all young spots which were studied. From older spots other fungi were obtained. Tnoculations with this Sphaeropsis produced typical disease in 5-20 days upon eaves. The fungus causing the leaf spot in nature is probably derived from cankers on the branches which are frequently abundantly infested.—F. L. StEvENs. Peat.—From the Geological Survey of Michigan there has recently appeared a volume on peat.?® The work consists of three separate essays under the fol- lowing titles: The ecology of peat formation in Michigan; The formation, character, and distribution of peat bogs in the northern peninsula of Michigan; Economics of peat. The author presents a classification of the Michigan peat deposits based upon (2) form of land surface, (6) method of development, and (c) surface vegetation, in which he seems to follow previous authors. e place taken by plants in peat formation depends directly upon their specific ecological demands, hence the floristic diversity which appears in the formation of peat in shallow depressions, upon flat areas and raised surfaces. Applying this principle, a thorough study is made of Mud Lake, which lies in the southern peninsula, and the successions are well traced out. The conclusion is reached that light is the Principal factor controlling the development of peat through its limiting influence on the growth of plants, both below and above the water level. Physical and chemical characters of the substratum, temperature, aeration, mechanical and Physiological effects of the wind, and competition are considered cooperating but secondary factors influencing peat development. In the second essay the northern peninsula is made the basis of study, and the vegetation of a large number of lakes and ponds is described in some detail, and the conclusions reached from the study of the southern peninsula substan- A comparison of the conditions found in the two peninsulas leads to the Statement that the noted variety of the sedge zone in the north is to be related to the fact “that in the cooler, more humid climate of the north, the shrubs men- Hioned are able to grow better in the water than they can in the south.” Froma Study of “Algal Lake,” a type of peat hitherto unrecognized, in this country at least, must be added to those which were known before, namely, algal peat, formed 7 almost entirely of the remains of one-celled or few-celled plants +0 part Tis appended a detail map of the original swamp area of the southern Peninsula; while part II is likewise accompanied by a map of the original vege- ‘ation of the upper peninsula. These maps should prove of great service, both in this field and as a permanent record of a vegetation too fast suffering de- struction, DAVIS, C. Ac, “Peat: Fecan: the report of the Geological Survey for 1906. PP. 95-395. Lansing. 1907, 72 BOTANICAL GAZETTE [ony It is to be regretted that fuller credit for most of the apparently new ideas is not assigned. One looks in vain for acknowledgment of the works of FrvH and ScHROTER, GANONG, and TRANSEAU, whose studies have partially covered — the significant results of Davis. The mention of these works in their proper places would relieve the book of much that might appear to be an original contribution. The greatest value of the book to the ecologist lies in its careful descriptions of various types of swamps and the detailed record of the distribution of peat-forming species. A complete index makes this material readily available. —LeRoy H. Harvey. Endodermis of ferns.—The sporadic occurrence of the endodermis and the modifications it shows have been frequently remarked. A comprehensive study of this layer in the fern stem and leaf has been made by BASECKE,?? whose contri- bution may be considered a companion paper to that of Rumpr° on the fern root. Following this writer, BASECKE distinguishes (1) the primary endodermis, — characterized by Caspary’s band, and (2) the secondary endodermis, in which the cell walls are more or less thickened and suberized. The leaves of the euspo- rangiate ferns lack an endodermis, while those of Osmundaceae show only @ primary layer; but most of the leptosporangiate ferns are well provided through- out the length of the leaf with a secondary layer. Anatomical and physiological studies show that food manufactured in a fertile leaf first supplies the sporangia, and any excess passes out through the vascular bundles. In rhizomes devoted to storage, only a primary endodermis is found, and in those which are active in propagating the plant a more or less impenetrable layer extends nearly to the ra growing point; hence the view is maintained that the secondary endodermis _ serves to prevent the escape of food from the vascular bundles while it is in process of transport. ie The second part of the paper describes a reinvestigation of the question as - the occurrence of cork in the ferns, and the conclusion is reached that true is never present, but that substitutes are frequent, such as ‘‘metacutinized” aS — of the outer cell layers. In this respect the ferns are less differentiated than the angiosperms. As to shedding of leaves, the author distinguishes three sorts of absciss layers, in contrast to earlier workers who were unable to find special i structures connected with leaf fall, A classification of the various m en a tissues of ferns concludes the paper.—M. A. CHRYSLER. Protection from light.—BaumErt reviews very fully3t the many ee that appear in literature as to the function of various structures in protecting 29 BASECKE, Paut, Bietrage zur Kenntniss der physiologischen Scheiden - es Achsen und Wedel der Filicinen, sowie iiber den Ersatz des Korkes bei dieseT Pian be zengruppe. Bot. Zeit. 66:25-87. pls. 2-4. 1908. ae __%° Rumer, G., Rhizodermis, Hypodermis, und Endodermis der Farmwurill: Bibl. Botan. 62: 1904. = Baumert, K., Experimentelle Untersuchungen iiber Lichtschutzeinrichtt an griinen Blattern. Beitr. Biol. Pfl. 9:83-162. figs. 6. 1907. 1908] CURRENT LITERATURE 73 mesophyll cells from excessive light, and made exact measurements as to the efficiency of some of them. Light from a lamp, concentrated by a reflector, was allowed to fall upon the experimental leaves at an angle of 45° in a suitable moist chamber, and the differences measured by means of a thermocouple of needle form, inserted between two pieces of the leaf, and connected with a galvanometer. The cooling by evaporation as a source of error during the exposure (10-15 min.) could not be wholly avoided, but was assumed to be nearly uniform in the control and the experimental leaves. The results show that hairy, scaly, shining, and glaucous leaves become less heated than the same leaves deprived of protection. A thick white coating of hairs, as in Centaurea candidissima, reduces the heating effect 37.5 per cent., shininess up to 30 per cent., and wax coating up to 13.6 per cent. A layer of water reduces it 19.2 per cent.; but this result seems more open to objection on the score of cooling by evaporation than the others, though the author takes it to be as valid as the rest. Reflection is held to be due in some Bromeliaceae to the inner epidermal wall, the cell acting like a concave lens, while epidermal cells that con- tain brown contents act as shades. The special value of the paper is in its appli- cation for the first time of quantitative methods, instead of deductive reason- ing.—C. R. B. Turgor and curvature.—The old problem has been again attacked by KErR- STAN,*? namely the question whether, under tropistic stimulation, there first occurs a variation in turgor that causes the curvature, both in growing parts and in motor organs. The evidence accumulating has been all against the idea, stood almost alone. Kerrstan adds his testimony that in most cases there is no acceleration of geotropic and heliotropic growth movements by a heightened turgor, and often the cells of the convex side become less turgid. When such ric, a very slightly heightened turgor was found in curved petioles, and he could be observed in the imperfect organs of Malvaceae.—C. R. B. ere eens . a Seager K., Ueber den Einfluss des geotropischen und heliotropischen Reizes Turgordruck in den Geweben. Beitr, Biol. PAl. 9:163~213- 1907- 74 BOTANICAL GAZETTE [yULY Mendel’s law in violet hybrids.—BramverD33 has given an interesting — account of the offspring of supposed violet hybrids which show that certain char- acteristics behave according to MENDEL’s law. The characteristics observed were the color of the capsule, purple vs. green; and the color of seeds, brown vs. buff. The parents of his plants were supposed to be hybrids between Viola hirsu- tula and V. papilionacea. With respect to the two characters considered, the supposed hybrids should be di-hybrids. The number of F, offspring was only twenty-one, but all four of the possible combinations were present and the larger number showed the two dominant characteristics, purple c psul rown seeds. Several F; families further demonstrated the Mendelian nature of these char- acteristics. The writer points out that Mendelian behavior in the offspring of the supposed hybrids demonstrates their hybrid character—G. H. SHULL. Age of Hepaticae.—CamppBeLt contends3+ that both the Hepaticae and Musci are old types, the perishability of their tissues and insufficient search accounting for the lack of known fossil remains. He finds in the wide distribution of certain genera of Marchantiales and Anacrogynae, and the cosmopolitan dis- tribution of many of their species, evidence of the relative antiquity of the groups, since these plants are not adapted to rapid distribution. In proof of the latter he cites a few experiments, the character of the spores, and the fact that no Hepati- cae have been found on Krakatau since the eruption, though Java with an abun- dant hepatic flora is in sight. Analogy from pteridophyte and spermatophyte distribution is adduced in support of this conception of the significance of bryo- phyte distribution. The weakness of the case js evident enough, but certainly it is as good as any, if one must speculate.—C. R. B. Klinostats.—VaN HARREVELD finds35 by chronographic tests that the klino- Stats in use at present are all defective in that they do not secure uniform rotation, especially when the axis of rotation is inclined or horizontal and the load is not exactly centered. The modern motor-driven forms are the least objectionable. This inequality of pace leads to definite and unexpectedly large geotropic responses and should therefore be eliminated. To obviate these difficulties, he has con structed an instrument upon new principles. It is driven by a weight automat cally raised, and it is released under pendulum control by a rachet actuated by an electromagnet. The intermittent shock of stopping is reduced by vanes ant a wheel train. Photographs and drawings are given and a full description 8 promised when the instrument has been exhaustively tested.—C. R. B. 8° BRAINERD, E., Mendel’s law of dominance in the hybrids of Viola. Rhodors 9: 211-216. figs. 2. 1907. : » D. H., On the distribution of the Hepaticae and its significanc’ — New Phytol. 6: 203-212. 1907. Bas HARREVELD, PH. vAN, Die Unzulanglichkeit der heutigen Klinostatet - pO Re ee Untersuchungen. Recueil Trav. Bot. Néerl. 3:173 ff. (pP- < a - 3. 1907. 2 1908]. CURRENT LITERATURE 75 Cytology of the ascocarp.—According to FRASER,3° Hwumaria rutilans (Peziza rutilans) shows some interesting features in the origin and development of the ascus. The ascocarp originates as a tangle of hyphae without any differentiated sex organs, but nuclei fuse in pairs and the cells containing the fusion nuclei form ascogenous hyphae. Nuclear divisions in the hyphae show sixteen chromosomes, as do also the first and second divisions in the ascus. These two divisions have the characters of the heterotype and homotype mitoses. The third division in the ascus has eight chromosomes. During the first mitosis in the ascus the two nuclei of the ascus fuse. The spores are delimited by radiations passing from the centrosome, but near the base of the spore vacuoles may take part in the process.—CHARLES J. CHAMBERLAIN. Fossil cycadophytes.— WIELAND37 has published a short preliminary account of his examination of some of the most famous specimens of the Mesozoic cycado- phytes preserved in European collections. The specimens described are those of ycadeoidea etrusca, C. Reichenbachiana, Williamsonia gigas, and Anomozamites minor. With his long training in the American forms, the author was able to detect features which had escaped previous notice, confirming his results as to the bisporangiate strobilus, the synangial microsporangia, the branching habit, etc. Of special interest are Williamsonia, which links up the Mesozoic with the modern cycadophytes, and Anomozamites, with its slender branching stem, small blade- like leaves, and small strobili, which is more suggestive of the dicotyledons than any known cycadophyte.—J. M. C. Plant remains in Scottish peat bogs.—In continuing his studies of the Scot- tish peat bogs, Lewis3® has published the results of his investigations in the Scottish Highlands and in the Shetland Islands. Most interesting details: are given in reference to the different zones, and the author summarizes the situation in the following statement: “All the Scottish peat mosses [bogs] show a definite Succession of plant remains. The oldest, in the south of Scotland and the Shet- land Islands, have an arctic plant bed at the base. This is succeeded by a forest of birch, hazel, and alder containing the temperate plants. A second arctic plant occurs above the ‘lower forest,’ and is overlaid in all districts (except the Hebrides and the Shetland Islands) by an ‘upper forest’ covered by several feet of peat bog plants.”—J. M. C. Blepharoplast and centrosome of Marchantia.—Escovez*® has studied Mitoses in the spermatogenous tissue of Marchantia polymorpha and Fegatella ee 3° FRaser, H. C, I., Contributions to the cytology of Humaria rutilans, Annals of Botany 22:35-55. pls. 4, 5. 1908. * WIELAND, G. R., Historic fossil cycads. Am. Jour. Sci. IV. 25:93-101. 1908. 38 Le The Scot a 8° Escoyez, Evp., Blépharoplaste et centrosome dans le Marchantia polymorpha. Cellule 24:247-256. pl. I. 1907. : 76 BOTANICAL GAZETTE [uty conica. ‘The results are different from those of IKENO in regard to the blepharo- plast and centrosome. He finds no centrosome in the mitoses preceding the mother cell of the spermatid, and believes that his failure to find one is due to the absence of such a structure and not to any defect in technique. Two blepharo- plasts were observed first in the mother cell of the spermatid near the plasma membrane, far from the nucleus. Escoyez does not consider the blepharoplast to be a true centrosome; yet he has not traced its origin, and whether it comes from within the nucleus or from a certain region of the cytoplasm is not settled. —S. YAMANOUCHI. Sorus of Dipteris.—Miss Armour‘? has studied material of Dipteris that included the younger stages of the sporangium. D. bijurcata showed simultaneous development of sporangia in the sorus, and D. conjugata sporangia of different ages. The former, therefore, conforms to BowEr’s “Simplices,”’ and the latter to his ‘“Mixtae.” The three species seem to make a series in the form of the leaf, with D. bifurcata as the most primitive, and D. quinquejurcata in an intermediate position; parallel with this is the division of sori, leading to increase in their number and decrease in the number of sporangia in a sorus; and finally there is the progression from the “Simplices” type to the “Mixtae” type. This series is thought to have progressed from such a type as Matonia.—J. M. C. Morphology of Symplocarpus.—RosENDAHL has investigated the embryo sac and embryo of Symplocarpus, and an abstract of his results has been published. The primordia of the flowers appear eighteen to twenty months before anthesis, the ovules being “formed” in the season (autumn) preceding pollination. The proembryo is of the massive type characteristic of the aroids, in this case i ovoid in form. There is a short suspensor, and the stem tip is organized in a groove of the proembryo which develops near the suspensor. The endosperm encroaches upon both integuments and even into the chalazal tissue; and in tum the massive proembryo (‘‘protocorm”) destroys the endosperm, so that finally _the embryo is freely exposed in the cavity of the ovary.—J. M. C. Proteases.—VinEs, in his fifth paper on this subject,? reports that oily seeds, those of hemp in particular, contain proteolytic enzymes which act vigorously without restraint from the oil present. He succeeded in isolating, for the first time from plant tissues, ‘‘a protease that is essentially peptic in its properties; — digesting fibrin to albumose or peptone, but not acting on albumose or peptone, whether produced by its own digestion of fibrin or added as Witte-peptone- Te facts justify the conclusion that the hemp seed contains two proteases, the on¢ . 4° ARMOUR, HELEN M., On the sorus of Dipteris. New Phytologist 6:38 figs. II-14. 1907. 5 * ROSENDAHL, C. O., Embryo sac devel pment and embryology of Symp: at joetidus. Science, N. S. 272209. 1908. . = Vines, S. H., The proteases of plants. V. Annals of Botany 222103145" 1908. . e 1908] CURRENT LITERATURE 77 peptase, the other an ereptase. He hopes soon to arrive at a general conclusion as to the nature of ‘‘ vegetable trypsin,” which by his admirable researches so far seems resolvable into a peptase and an ereptase.—C. R. B. Structure of chloroplasts.—This has long been in doubt, the current doctrine being that the ordinary chloroplast consists of a stongy stroma in whose meshes the chlorophyll is held as a green fluid. Prresttey and Irvrnc show‘? that in the large chloroplasts of Chlorophytum elatum, Selaginella Kraussiana, and S. Martensii the chlorophyll is restricted to a peripheral zone, probably less than 1 thick, where it is held in the meshes of a spongy stroma. This agrees with the arrangement theoretically best according to TrmmertazeErF. The authors also confirm the neglected observations of NAGELI and TimerazerFr on the splitting of the chloroplasts in solutions of low osmotic pressure.—C. R. B. Morphology of wheat.—ArrHur H. Dupiry,‘+ in a presidential address before the Liverpool Microscopical Society, presented an account of floral devel- opment, sporogenesis, and embryogeny in wheat. A summary of his results is as - follows: the archesporium of the microsporangium is a single row of cells, two or three divisions occurring before the mother-cell stage is reached; the arche- sporial cell of the megasporangium does not cut off a parietal cell, but produces directly the linear tetrad, the reduction number of chromosomes being eight; . large development of antipodal tissue occurs; and the embryo is said to be derived from the “apical cell only”’ of the proembryo.—J. M. C. Scion and stock.—GurtcNnarp has made another attempt to settle the question whether compounds peculiar to either scion or stock are able to migrate past the point of grafting.*5 When a plant which contains an HCN-glucoside is grafted ona Plant which contains none, or conversely (GUINARD used Phaseolus lunatus, Photinia serrulata, and five species of Cotoneaster), there is no transfer of this glucoside in either direction. This adds one more bit to the negative evidence eas accumulating against the uncertain positive claims of such migration. The Paper contains a good history of the question.—C. R. B. Tolerance for salts.—Continuing their work on the relation between alkali Bey and vegetation, KrarNey and Harter, testing pure solutions of various Xa. find¢* that different species and even different varieties of the same species lier considerably in resistance to the action of magnesium and sodium salts. Sar ee oa ed RIESTLEY, J. H., and Irvinc, ANNIE A., The structure of the chloroplast sidered in relation to its function. Annals of Botany 21:407-413- figs. 2. 1907- Liv, ie Duptey, ARTHUR H., Floral development and embryogeny in wheat. Report *rpool Micros. Soc. 1908 1-19. pls. I, 2. eae Guicnarp, L., Recherches physiologiques sur la greffe des plants & acide Atha Ann. Sci. Nat. Bot. IX. 6:261-305. jigs. 9. 1907. erie Kearney, T. H., and Harrer, L. L., The comparative tolerance of various : 's for the salts common in alkali soils. U.S. Dept. Agric., Bur. Pl. Ind., Bull. 13. pp. 22. 1907. 78 BOTANICAL GAZETTE [JULY Seedlings grown from fresh seed are much more resistant than those from older seed. By different experimentation they confirm the findings of other observers as to the power of calcium salts (they — of sulfate) to offset the toxic action of magnesium and sodium salts.—C. R. Edwin James.—Students of taxonomy will be interested in a recent paper by PAMMEL,*7 which gives an account of Dr. James, whose name is so intimately associated with the early explorations of the Rocky Mountain region. Not only numerous plants, but also a mountain peak bears his name, though the latter is now better known as Pike’s Peak. Through papers found in the Parry herbarium, local biographical sketches, and information obtained directly from relatives, a very satisfactory account has been prepared, and the personality of JAMES is thus rescued for botanists—J. M. C. Conifers of China.—The late Maxwett T. Masters left a paper on the dis- tribution of conifers in China, which has just been published.4* The total number of species known from China at the time of writing (June 20, 1907), inclusive of Formosa, was 87, distributed among 23 genera. In one table China and Japan are compared; the former containing 87 species, of which 42 are peculiar; th latter 48 species, of which 15 are peculiar. A large table shows the distribution of all the native species of China in the various regions of the empire as well as in neighboring countries.—J. M Nuclear division in Basidiobolus.—Oxive4? has studied nuclear and cell division both in the beaks and in the tative cells of Basidiobolus. The spindle is broad, cylindrical, barrel-shaped, and intranuclear. At the equatorial plate stage it shows three darkly staining regions, the chromatin plate at the center and two pole plates at the ends. The wall is formed as a ring, which begins at the periphery of the cell and closes in like an iris diaphragm, as in many algae, a mode of growth quite different from that described by FarRcHILp in 1897 CHARLES J. CHAMBERLAIN. Variegation and infectious chlorosis.—Those who are interested in these problems will find useful an extensive paper by LinDEMUTH,*° which embodies a precise and comprehensive exposition of the results of his studies on variegation, which go back as far as 1870, and have been continued with more or Jess vigor to 47 PaMMeEL, L. H., Dr. Edwin Lee Annals of Iowa 8:161-185, 277-79 es Also distribaied’ as a separate 8 Masters, MAXWELL T., On the — of the species of conte in the font districts of China, and on the occurrence of the same species in neighboring countries. Jour. Linn. Soc. Bot. 38: 198-205. ees 49 OLIVE, E. W., Cell and nuclear division in Basidiobolus. Annales Mycol. 5:404-418. oi: 10. 1907. muTH, H., Studien iiber die sogennannte Panaschiire und tiber einig Scdédtragie Esbaeee Landw. Jahrb. 36:807-862. pls. 8, 9. figs. 16. 19°7- 3 net RE eM ie Seay sh 1908] CURRENT LITERATURE 79 the present time. The paper includes a summary of many scattered contributions, and makes it clear that he had recognized, much earlier than Baur, the infectious character of certain forms of variegation. He contends, rightfully, that chlorosis is an inept term.—C. R. B. Sap rot of red gum.—Von ScHRENKS' describes diseases due to fungi which infect the sapwood of red gum (Liquidambar) when the logs lie in the forest while wet, and continue to spread, to the destruction of the lumber when cut. Poly- porus adustus, Polystictus hirsutus, and Poria subacida are the most frequent enemies, but there are a number of others. Sap rot may be prevented by hasten- ing the drying or by coating the ends of the logs as soon as cut with hot coal tar. Similar diseases injure the heartwood of red gum and also affect the swamp oak and maple. —C. R. B. Cytology of Microsphaera.—Sanps5? has shown that during all stages in the life-history of Microsphaera a central body is differentiated as a permanent nuclear structure, which serves as a point of attachment for the chromatin. It is always extranuclear, never intranuclear, as claimed by Marre and GUIL- LIERMOND. The delimitation of spores is accomplished by the astral rays persisting from the third mitosis in the ascus. The work in this respect Supports the conclusions of HARPER rather than those of FAULL.—CHARLES J. CHAMBERLAIN, Morphology of Cornus florida.—MorseEs3 has investigated Cornus florida and found the following facts: the male gametophyte passes the winter in the two- celled stage; no walls separate the nuclei of the linear megaspore tetrad; the embryo sac probably passes the winter in the eight-nucleate stage, which persists Until the last of May, when pollination occurs; the synergids are slender cones Projecting far into the micropyle; the endosperm tissue is formed first in the micro- pylar end of the sac, and by the middle of July completely fills the sac.—J. M. C. Fossil flora of Florissant —CockERELL*4 has enumerated the known flora of the Florissant shales (Miocene), including 106 genera, 45 of which occur in Colo- Taco today. Of the genera not occurring now in Colorado, 36 occur in our eastern and southern states, the conclusion being reached that a flora similar to that of the Carolinian region occupied the Rocky Mountains during the Miocene. About 5° new species are described, including a Chara, a fungus, four ferns, and two 8yMnosperms.—J. M. C. errr sia gps H., Sap rot and other diseases of the red gum. U. S. Dept. €., Bur. Pl. Ind., Bull. 114. pp. 32. pls. 8. 1907- : Tass M. C., Nuclear structure and spore formation in Microsphaera alni, ~ Wis. Acad. Sci. 15:733-752. pl. 46. 1907. oe WILtiaM CiirForp, Contribution to the life history of Cornus florida. Agri *# COCKERELL, T. D. A., The fossil flora of Florissant, Colorado. Bull. Amer. » Hist. 24:71-110. pls. O-I0. 1908. 80 BOTANICAL GAZETTE [yory Trees and shrubs.—The second part of the second volume has followed’ the first part promptly, and is devoted to species of Crataegus and Viburnum. ~ SARGENT describes 10 new species of Crataegus, 7 of which are from Missouri; q while REHDER presents and illustrates 13 species of Viburnum from China and 4 Japan, 3 of which are new. The species of Viburnum are followed by a synopsis | 4 of the genus as displayed in eastern Asia, sf species being recognized under 9” : sections, and g of these species are new.—J. M Cytology ot geotropism.—GrorGEVITCH contributes little that is new by his” study of the cytology of roots of Lupinus albus when stimulated by gravity.° He correlates, much as Némec did, though with differences in detail, the aggrega tion of the protoplasm and the position of the nucleus with geotropic stimula are contents of normal and stimulated roots. It is not possible, however, to say whi it these mean.—C. R. B Sexuality in Ceratiomyxa.—OLiveEs’ has shown that the cleavage of the plas: claimed by Fammyrzin and Worontn. Toward the close of the cleavage stage — there is a fusion of nuclei in pairs, followed almost immediately by synapsis and two rapidly succeeding divisions, which are regarded by the author as reduction divisions, and give rise to four-nucleate spores.—CHARLES J. CHAMBERLAIN. Dumortiera autoicous.—Erwnst reports in a preliminary papers* that Java material of Dumortiera trichocephala (commonly) and D. velutina (spa have both antheridia and archegonia on the same receptacle, though on diffe lobes. A single instance of the same thing has been observed (hitherto oa lished) by Dr. W. J. G. Lawn, of the University of Chicago, in Mexican ma of D. hirsuta collected at Xalapa, V. C.—C. R. B. Anatomy of Isopyrum.—Hoim® has added Isopyrum biternatum to his ana tomical records, including with the anatomical details a discussion of geogr@ distribution and generic limitations.—J. M. C. 55 SARGENT, C. S., Trees and shrubs. Illustrations of new or little known ig ie plants, prepared chiefly from material at the Arnold Arboretum of Harvard Univer ol. II. Part. II. pp. 57-116. pls. 126-150. Boston and New York: Hougt Mifflin, & Co. 1908. 00. 56 GEORGEVITCH, PETER M., Cytologische Studien an den geotropisch Be Wurzeln von Lupinus albus. Beihefte Bot. Cent. 221:1-20. pl. I. 1907- _ 7 Ottve, Epcar W., Cytological studies on Ceratiomyxa. Trans. Wis. Sci. pick take pl. 47. 1907. 58° ERNS r androgyne Inflorescenzen bei Dumortiera. Ber- Bot. Gesells. ‘Os: pee pl. 13. 1907. 5° Hotm, Tueo., Isopyrum biternatum T. & G.; an anatomical study. Am. “ Sci. IV. 25:133-140. figs. 3. 1908. RSE Lo ae ae Cee) oe hii EaeE Tae ws: THE August 1908 Editors: JOHN M. COULTER and CHARLES R. BARNES CONTENTS Floral Succession in the Prairie-Grass Formation of Southeastern South Dakota LeRoy Harris Harvey_ Undescribed Plants from Guatemala and Other Central - American Republics John Donnell Smith A Method for the Quantitative Determination ak Transpiration in Plants Geo. F.'Freeman The Toxic Property of Bog Water and Bog Soil Alfred Dachnowski Briefer Articles The Flowers of Washingtonia S.'B. Parish Current Literature The University of Chicago Press CHICAGO and NEW YORE William Wesley and Son, London Che Botanical Gazette HA Monthly Journal Embracing all Departments of Botanical Science Edited by JoHN M. CouLTER and CHARLES R. BARNES, with the ae of other members of the 3 botanical staff of the University of Chic Issued August 22, 1908 Vol. XLVI CONTENTS FOR AUGUST 1908 No, 2 (LORAL SN IN THE PRAIRIE-GRASS FORMATION OF SOUTHEASTERN SOUTH DAKOT CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 113 es THREE FIGURES). LeRoy Harris Harvey - : 81 UNDESCRIBED PLANTS FROM GUATEMALA AND OTHER CENTRAL AMERICAN REPUBLICS. XXX. John Donnell Smith bh METHOD FOR THE QUANTITATIVE DETERMINATION OF TRANSPIRATION IN PLANTS (witH onE FIGURE), Geo. F Freeman - - - 118 THE TOXIC PROPERTY OF BOG WATER AND BOG SOIL ib SIX noe Alfred Dachnowski— - : - 130 BRIEFER ARTICLES THE FLOWERS OF WASHINGTONIA (WITH FIVE FIGURES). S. B. Parish - - - 144 URRENT LITERATURE BOOK REVIEWS 3 E : 3 : c 2 3 - - - - 148, THE QUESTION OF SEX. PLANKTON OF ILLINOIS RIVER. FLORAL MECHANISM. MINOR NOTICES - ~ ‘= : : : & 3 , 2 : ee 2: NOTES FOR STUDENTS - be K i = ss x - : - - : mee Ki otanical Gazette is published monthly, [The subscription price is $7.00 per year; the price is 75 cents. [Postage is prepaid by Sg —— on ail orders from the nae States, oa), Shan stage is het iste as follo , 35 cents on 1 subscriptions {total $7.35), on single copies, 3 veer om as pares. for all ee er countries in the Remi $ on annual riba oe (total $7.84), on single’ copies I1 ‘seem (total 86 cents). N vo should be made payable to The Uae of Chic cago Press, and should be in Chicago or ef Beek exchange, postal or express money order. 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A table showing perancs mate ph of ee separate order blank which accompanies ae : proof; a copy will be sent on reque: Enter, ed August ar, 1895, at the Post-Office at Chicago, as second-class matter, under Act ‘of Congress March 3, 1879, VOLUME XLVI NUMBER 2 BOTANICAL GAZea ee AUGUST 1908 FLORAL SUCCESSION IN THE PRAIRIE-GRASS FORMA- TION OF SOUTHEASTERN SOUTH DAKOTA THE PREVERNAL,, VERNAL, AND ESTIVAL ASPECTS CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY I13 LeRoy Harris HARVEY (WITH THREE FIGURES) The western part of Iowa, the eastern and northeastern counties of Nebraska, and southeastern South Dakota lie in the drainage basin of the Missouri. This tri-state area is well within the prairie region of that vast and far-reaching prairie province of the middle west. This area is only a part of the Ponca District of Pounp and CLEM- ENTS," being more strictly Dakotan than Nebraskan, and may be considered as representing a transition between the more meso- phytic eastern areas of Iowa and those dominantly xerophytic some- what to the west, with which it shows the closer floristic agreement. Its composition is thus twofold, pointing to the primitive and more xerophytic stages of the past and at the same time prophetic of the mesophytic stages to come. This aberrant character links it strongly to the xerophytic prairie to the west and southwest, from which it is genetically descended, and the prophetic character links it to the more mesophytic prairie of western Iowa, which has encroached ‘ver westward. Under this migration tension from the southeast and €ast the primitive prairie has retreated, civilization always being 4 potent factor in this succession. ; : Study began in this tri-state region in the fall of 1903 at Sioux City, Iowa, and was carried on during that fall and the next summer *Pounp, R., and Crements, F. E., Phytogeography of Nebraska. 1900. 81 82 BOTANICAL GAZETTE {aucust in the contiguous portions of Iowa, Nebraska, and South Dakota, In the fall of 1904, Yankton, South Dakota, became the base station, © and for the next three seasons (1904-1907) the work was carried on from that point. During this period the greater part of South Dakota east of the Missouri was visited, and repeated trips were made into contiguous Nebraska and into Iowa, while at the same time detailed study of a restricted area was being prosecuted. This local area upon which study has been focused lies in the township of Yankton and embraces about 49 hectares, being a rectangular strip 1210™ north and south by 405™ east and west. The topography is uneven and comprises a series of prairie knolls and slopes, separated into two groups by a gentle drainage valley which traverses it in a southwest and northeast direction. The knolls are low and their slopes gentle, scarcely higher than 1o or 15™, with a gradient never exceeding 30 or 40°. The entire area is largely underlaid by glacial gravel and clayey till. The former mainly constitutes the knolls—the humus is here the most shallow, averaging only about 15 to 20°" in depth. Off from the knolls on the level the humus caps the deposit of clayey till. On the lower erosion slopes (25 to 30™) and in the drainage valley (60°™ plus) the humus has accumulated to a greater depth, sufficient in the latter to bury the till beyond the zone of root activity. The humus is in all cases till or gravel modified by atmospheric, organic, and biotic agencies. To insure uniformity the nomenclature of Brrrton and BRowNs Illustrated flora has been followed, except where it has conflicted with the verification of grasses made for me through the United States Department of Agriculture by Mr. Percy L. RICKER and Mr. D. A. Broptz, to whom I am greatly indebted for this courtesy: This problem has been carried on under the direction of Dr. . C. Cow Es, to whom I wish to acknowledge my indebtedness for many valuable suggestions and criticisms during the progress of the investe gation. Geology and topography _ To appreciate fully existing conditions, an epitome of the post: Cretaceous geological development of the region is necessary. ~ Cretaceous was terminated by that great uplift and crustal movement which formed the Rocky Mountains and gave birth to the ne 1908] HARVEY—PRAIRIE-GRASS FORMATION 83 features of the Missouri valley drainage. This movement particu- larly affected this region by elevating it from an estuary condition to a point considerably above sea-level, and even probably many feet above its present level. This uplift inaugurated a period of vast erosion, and before the advent of the ice the Missouri had cut its present great valley at least 20 to 25™ below its present level. With the Pleistocene came the glaciers. While doubtless there Were five periods of glacial advance and recession in the region, we need concern ourselves now only with the second, the Kansan, which spread from the Keewatin center and deposited over this entire region the Kansan drift sheet, obliterating the questionable pre-Kansan. The Illinois, Iowan, and Wisconsin epochs followed successively, only the latter reaching into southern South Dakota, where a lobe of the Altamont moraine pushed down between the Big Sioux and Missouri Rivers, reachin g approximately to Vermillion, South Dakota. The Kansan must have seriously interfered with the established pre- glacial drainage, greatly rejuvenating it, at least along minor lines. 5s seems probable also that subsequent erosion mainly sought out Previous lines, largely reestablishing the post-Pliocene drainage system. The Wisconsin likewise disturbed and caused a readjust- ment of this drainage system, which could have differed but little from that previously worked out in the Kansan. Upon this read- Justment of the post-glacial Wisconsin drainage topography, there followed the deposition of that much mooted deposit, the loess. The region divides itself naturally into two great topographic id the rolling upland prairie and the flood plain, which cuts the Prainle in a general northwest and southeast direction. On either = the flood plain is limited by the escarpments of the Missouri. aa flood plain extend the minor flood plains of its tributaries, . aes ‘ssecting the upland. The vast valley is cut out from 25 Wario: — in the upland and presents a flood plain varying from a sei ‘trace to frequently ro™ in width. tiie ee now presents an almost perfectly developed erosion quent} gel predetermined in the Kansas drift sheet and subse- tter A Spite by the Wisconsin drift and loess deposit. The consin sie frequently has a depth of so™ to the south of the Wis- area, thins out northward. The escarpment bluffs are 84 BOTANICAL GAZETTE [aucusT steep and high, but pass back into a complex of gently rounded, — semi-detached hills, which present a sinuate or undulating sky line of jumbled peaks; it is a vast mountain system in miniature. Backa few miles from the bluffs these hills pass imperceptibly into the low, rolling prairie hills, which extend with scarcely a variation in either direction. So perfectly is this tributary drainage system established that upon the prairie swamps and “sloughs” rarely occur. The small streams which have threaded the upland are characterized by ravines of depth and precipitousness, especially in the loess, where they usually end abruptly in a bluff, again dividing the upland into a series of ridges, intricately related, which pass back into the low, rolling hills of gentle profile. Origin of the prairie The uplift of the Rocky Mountains, which terminated the Cre- taceous, introduced a modifying element which exercised an evel increasing influence upon the climate of the Great Plains region. Intercepting the eastward-moving moisture-laden winds from, the Pacific, a decrease in the annual precipitation to the east of the range must of necessity have followed. The greatest reduction would have been nearest the mountains, decreasing to the eastward. When this interior continental land was finally left by the interior sea and opened to migration, invasion must have been in large degree controlled by this graduated distribution of rainfall. The subsequent origin of the Cascades could have served only to accentuate this distributional difference and reduction in precipitation. Under such conditions the Tertiary phytogeographical distribution of this central region must have been adjusted. Whatever the source, it would seem highly probable that while the entire Mississippi valley was occupied by the rich Tertiary forest, the region lying to the west and bounded by the Rocky Mountains and extending northward into Assinaboia Was: on account of the low precipitation, denied to tree invasion and a” | to be occupied by a prairie formation, increasing in its xerophytis™ westward just as it does today. Toward the close of the Tertiary (late Pliocene) fossil evident’ points conclusively to climatic change. A retrogressive successio? floral waves swept southward under the influence of the 1908] HARV EY—PRAIRIE-GRASS FORMATION 85 falling temperature of the Pleistocene. In this glacial movement, the plains region, unable to support tree growth, acted as an entering wedge, causing an east and west divergence. One wing of the mi- gration, dominantly coniferous, followed the Rocky Mountains southward; the other, typically deciduous, sought the Mississippi and its tributary valleys as a migration track; while the prairie moved directly toward the Gulf. At the time of maximum ice advance the descendants of the Tertiary forest were mobilized in the southern Appalachians about the Chattanooga region as a center (ADAMS :02), while the prairie formation concentrated in the southwestern United States, with a possible center in the region of northeastern Texas and eastern Oklahoma and southern Kansas. With final glacial retreat from this region and subsidence of the glacial sea, Migration tension was removed and distribution tension became active. The life waves now in succession rolled northward. The content of our flora demands a consideration of the third wave only. A study of the floristics shows indisputably the commingling of forms of diverse geographical affinity. An unmistakable floristic relation, in Many cases specific, exists with a southwestern and Southeastern center of post-glacial dispersal.2 To the east and southeast the deciduous forest type becomes increasingly character- 'stc, while to the west and southwest the plain or prairie type gradu- y predominates ; the region thus lies in the western border of the tension zone in which migration from these two competing centers of distribution meet. From the southeast the dispersal route has been up the Missouri valley; while the northwestern migration has cg diagonally across natural drainage lines, following the upland s. Forest invasion of the prairie : sige the arborescent elements of the southeastern biota, migrating P the valleys of the Mississippi and of the Missouri and its tribu- ecard (99, p. 82) says: “There are 66 or 67 species of native trees in Ne- a » and 56 Or 57 CMILLAN 92, Pp. 653, a show indubitahl tern origin. Of the native trees of South Dakota at least 75 per cent. ‘ i le Southeastern affinities. e presence of such genera as Opuntia, Strongly a Mentzelia, Croton, Bouteloua, Bulbilis, Lygodesmia, and Aplopappus peaks the southwestern alliance. 86 BOTANICAL GAZETTE [AucusT taries, reached the prairie region they were unable to occupy the high lands, but occupied the flood plains and adjacent slopes. There is no evidence to indicate that the then existing topographical and cli- matic conditions differed radically from those of today. Again these elements have today their most widespread distribution, a condition at once intelligible when related to physiographic development in the working-back of streams and the increase of flood plain. ‘Two salient points may now be noted: the initial and the continuous subsequent preemption of the upland by the prairie formation, and secondly the continuation of initial climatic conditions. The initial causes which operated to restrict tree invasion and ecesis upon these prairie-covered uplands would thus seem to have their duplication in those natural factors which operate to that end at the present time. Under the discussion of ecological factors of the region it will be shown that there is a coincidence of factors operating most antago- nistically against tree growth upon the upland. The almost entire absence of fungi upon the prairie cannot but be significant. The roots of most of these deciduous trees are obligatively provided with symbiotic mycorhiza and the absence of their specific fungus would preclude advance. Hence fungal infection of the prairie soil must precede or at least accompany forest encroachment. Again, the difficulty of seed germination, almost impossible either because of 4 dense sod or a lack of soil moisture, successfully checks invasion. In consideration of these precarious climatic factors, peculiar edaphic conditions, and the fact that if planted upon the prairie trees thrive, I am led to the view that the question of non-invasion upon the prairie proper is primarily and initially one of pre-occupation and the inability of seedlings successfully to withstand the extremely seve conditions of the first winter’s exposure. In the positive and coinc dent interaction of unfavorable biological and climatic condition may be found a cause sufficient to account for tree absence upo2 the prairie and the slow migration of tree species into this region. While these causes are all sufficient, yet we must not disregard # secondary and artificial though highly cooperative factor, which ™ recent times must have served in many places to prevent tree &'*" lishment. I refer to prairie fires; yet even in the absence of prairie fires for half a century the prairie stands uninvaded except in cas® : 1908] HARVEY—PRAIRIE-GRASS FORMATION 87 of physiographic development (BEssry ’99). And again, as the prairie existed as a climatic formation long before these fires, either of Indian or Caucasian origin, swept the prairies, it would appear that this fire factor has been overestimated by many and is in no sense to be regarded as the fundamental factor. That there is, nevertheless, an extremely slow advance of the forest usually through the medium of its forerunner, the shrub association, whose pioneer Symphoricar pus occidentalis is followed by Rhus glabra, is very evident. While the above factors are seemingly adequate to account for tree absence upon the western upland prairie, yet in light of the prairie as a natural climatic formation it would seem more proper to make the problem one accounting for the occasional presence rather than the general absence of trees. A future paper is planned to discuss the factors controlling this encroachment. The period of growth resumption Not until about the first week in March are climatological condi- tions at all favorable to an awakening of vegetation, and then only on infrequent days; but the month as a whole is marked by the open- =“s of flower and leaf buds of trees and the beginning of the germina- - ion of prevernal annuals and the formation of the basal rosettes of the Perennials, though some tide over from the previous season. The prevernal bloomers naturally make most rapid progress, aided by their geophytic habit. Not infrequently the temperature falls below freezing and killing frosts ordinarily result. Light snow storms, Which rarely occur, may temporarily retard growth. The conditions ome progressively more favorable and pass insensibly into the Period of the prevernal flowers. The usual snows and rains of the early part of the month assure abundant moisture. The chresard, which is about 18 to 20 per cent. m the early days of the month, decreases to about 14 per cent. at the middle, and to about 12 per cent, toward the last of the month, thus Siving an average chresard of some 15 per cent. The different ©xposures of the prairie hills, knolls, and ravines progressively recover m the effects of winter in the following order: southeast to south- West, southwest to northwest, northeast to southeast, and northwest to northeast, The frost clings to the northern exposure in ravines, [AUGUST — BOTANICAL GAZETTE 88 atter lyleaving toward the lat : g only h, particu- Beswe 3 & t of the mont » Pp 2 Spe beg oo pe is exposure is {NOLLVE In x aa 2 hen this exp “OAVAE HAULVIRY | 1 S34 = 8, larly w On March 16 on o a rs d n Sag. ho 8 forested. of a WOAH . n a 8 xposure cutee hie is ee 4 - = = a northwest e c frost was E ‘ p = € S13 : " ze prairie knoll t following paesaryp ney tre & 336 rded at the uRayy os Giga t= alate dns Teco e of slope see ae 49482 depths: at bas i | Sig ¢ agree eee at middle of aa ej wre | ie ef 2538 13.970, rest Cofiaa age ine ae saa Boe eh 8 eee é Ro Bs 30.4 ? low 35°", Thus ae “a eee! ge See siderably be sure Sle es a: $5. of the exposure — Se ees Ss Gee Ewes. the base slowly — P Sts =. cee ae h more slowly — 5 of Beast recovers muc ondition “Sumsing | is |Z = Bee oe e crest, ac ee “urgsung | i | 2 aa ce ae lly true for all eves a RE, : z s: $3 S : equa ae ‘ ; * |ssompnop _ zz 6S ce m4 5 4 holding q ia vegetation = RR | ow oe eas exposures; hen the upieal 8 a * Be4s 2 : n 4 tees % S 8 a ql a 3 starts earlier upo he ela | Lanepy | + i & 50s = However, t : re |B yg fBea3 slopes. toward the — — g Pa > Heras d increases to On == i] Pa < bese. 3 4 f= sar f mIOL | 3 |g o AGE. | the slope. eee I : Seibes base of im je e's = oe) . 6 the slope c % fe (2 g 3 2.88 March 1 chresard a SP COE | Be gis 2 question showed a cent., ATI ~ o 3 os, er : : & 3 ZR eg EE he crest of oe aware oS Poeas att : f 14.1 per = BR 1gke he middle o of 0 (4 7s ee d at the base ! . 5 6g ae "anew ;2 18 — ee. cent., an the differences 2 2 227535 18.2 per cent., ced an cae Wine Sly os eghts ing more pronoun han Bored. | 1 oF 232k. being eater t 5 le & aes the chresard gr aspect. . Ss a. a t SA eee So5 uen Rte eo worpenp = ee 8% 79 gs in any subseq nditions : wed | ig gaeeces The physical co wn in 3 ao ho Teapot oy Ser ~ & g ‘ ares sy Ola gsi ge 5 of the period ble ues ~ |? SaaS £ 3 diacent table. 8 0 3 s+ £ g £ the a J : ;|3 sagsese floral aspect : |= 828 727 —_—Prevernal insonly 3) umuray | B ghbccea ivity begins q || s2eease Floral acti pe “os Bs Ee ee Perreererr in the first wee ee tae A288 #3 in a Pde encore _ aie bd Ge Foe 3 E s a ® & : =] and is characterized by | 1908] HARVEY—PRAIRIE-GRASS FORMATION slow and progressive flowering of six forms, extending up to the last week in April, when an apparent break in floral continuity occurs, no forms flowering for a week or ten days. This break very naturally segregates the pre- vernal floral aspect. In addition to the floral forms this aspect is conspicuous as the time of appearance of the rosettes of the vernal, serotinal, and autumnal perennials, and seedling annuals of these same aspects. No facies is estab- lished, and the tone of the formation is that of winter and early spring, mainly produced by the standing brown stalks of Solidago rigida, Helianthus scaberrimus, and Verbena stricta of the autumnal aspect, which gives everything a brownish cast, enlivened here and there by the mats of Antennaria cam- Pestris and A. neodioica, and at the base of slopes and in depressions by the green of Poa pratensis sod. At the base of slopes now and then are to be seen clumps of green, produced by the unfolding leaves of Colonies of Symphoricar pus occidentalis. To complete the aspect, dotted here and there are the floral forms which characterize it. Ruderal species are noticeably absent. The pertinent climatological conditions of the prevernal flora] omy from the adjacent table. On only el cent. of the days does the mean ns age temperature rise above 6° C., with a — between —6° and 29°C. Coupling a oe an average soil temperature of 7) Srowth conditions are seen to be om favorable, The prevailing wind 8 3S northvest and with a mean PREVERNAL CLIMATOLOGY 89 is} NOLLVUOdVAL sa HALLVTAQ - ALG oe GTALLVIaa NVA Oke o paesaiyo 5. uray x - ° 8 pieya SS 7) ueayy ; ™ pryjoy | BS uray Q *yua9 Jod Ce) aurysung | © = Ssourpnoyo oe 3 uy | + Ayisuayuy + aanepy | 10 8 1?) THIOL | ae z g a Ajrep ureyy Q sfecT ° AyDopea 4 4ym0oyq | 4 g yuaut = ~oaourejoy, | OD S woNserIp = 6) weet | So, _ Fy g 3) un |} : : 3) go BOTANICAL GAZETTE [AUGUST _ hourly velocity of 11 miles, which is not exceeded during the other aspects. Precipitation is slight (7.87°™) and falls on only about 33 per cent. of the days. The average cloudiness of the sky (4.7) is low, and the sunshine (63 per cent.) is correspondingly higher, resulting in a low light intensity (0.547). The saturation deficit is here not at its maximum (36.3), but, augmented by the high wind velocity, evaporation, which must necessarily serve as a rough comparative index of transpiration, is rising in amount. While far more favorable for vegetation, it becomes progressively more 80, the last half of the aspect presenting conditions in soil and ait noticeably more congenial to growth. The chresard decreases steadily during the aspect from 14.8 per cent. on April 17 to 12 per cent. on April 25, and a marked difference in holard was evident at crest (15.8 per cent.), slope (18.4 per cent.), and base (22.6 per cent.) on April 18. The average chresard is 12.8 per cent. SPECIES OF THE PREVERNAL ASPECT Facres.—None. PRINCIPAL SPECIES.—Antennaria campestris,t Carex pennsylvanica,T Peu- cedanum nudicaule,} Pulsatilla hirsutissima.* s SECONDARY SPECIES.—Astragalus crassicarpus,t Peucedanum foeniculaceum, Draba micrantha, Ranunculus ovalis. * Not occurring in area proper but in vicinity. + Forming associations. The earliest flowering form is Pulsatilla and occurs copiously 1 subcopiously and characteristically upon the upper slopes of the prairie hills. It appears several days earlier upon the south to south: west exposure, which holds equally true for the other prevernal bloomers. The early warming-up of this exposure accounts for above phenological precocity. But the greatest abundance of get prevernal forms occurs on the north to northeast exposure. Mature — tion follows close upon anthesis, which likewise holds for all prevernal z flowering species. of Pulsatilla is followed by the blooming, during the first week April, of Peucedanum foeniculaceum and P. nudicaule. The formet with its umbel of yellow flowers is of rare occurrence; but the Inti?’ with its umbel of white flowers appears even copiously in tC plats, and in its distribution occurs mainly upon the upper xerophyt s 1908] HARVEY—PRAIRIE-GRASS FORMATION ‘Ql slopes of prairie knolls where the grasses are bunched and the asso- ciation more or less open, though rarely seen at the crests; it thus not infrequently exerts a subtone effect at short range. It is perennial by means of its geophytic root. With the elongation of its peduncle and spreading of its umbel in maturation during the last week of the aspect, it becomes more conspicuous and persists thus far into the vernal aspect. The beginning of the second week of the prevernal aspect sees Carex pennsylvanica in full bloom. It occurs copiously, extending well up to the crests of knolls, but more abundantly on lower slopes, yet never influences the tone of the aspect. In places Carex may assume almost facial rank, but always maintains a bunchy or isolated distribution, which, however, is quite general. The peculiar yellow- ish-green shade of its leaves and its yellow staminate spikes which appear after the stigmas make it conspicuous. It is a perennial of xerophytic tendencies, propagating itself by rootstocks and stolons. Carex is shortly followed by the flowering of Antennaria campes- des and with its white tomentose leaves, scapes, and papillate heads, . Sives a characteristic local tone to this floral aspect, even from a distance. It occurs usually gregariously, being one of the two mat- forming species of the formation, and is very generally distributed throughout, facilitated by its perfect adaptation to wind dispersal. The mats themselves may be isolated or gregarious, as many as twenty having been noted in a plat of 6454™, yet single mats frequently cover re ", averaging about 1000 plants to the square meter. Propaga- tion is by stolons and migration is centrifugal, with a slow but positive °ccupation. Mats unite and take complete possession of extensive oes yet it yields before Poa pratensis, in no way being able to old its own against this sod-forming mesophyte. oan Seainieg floral aspect of the formation is terminated by the Pe age of Ranunculus ovalis, Astragalus crassicar pus, and Draba ities: ‘as the end of the third week of April. They appear thr hipecs 2 simultaneously, but in no way contribute equally to pect. Draba occurs only where the soil is exposed and the a hence on upper xerophytic slopes, and appears to be Whenever a close association is formed. It is an annual marked xerophytic tendencies, its leaves being basal and heavily g2 BOTANICAL GAZETTE [AUGUST a eS ; pubescent with stellate hairs. It is scarce and its small white flower inconspicuous, so in no respect does it influence the floral tone. Ranunculus is even more restricted, occurring sparsely on lowest slopes and in depressions on the higher slopes, and is apparently related to a high water content of the soil. Its yellow petals soon fall, and its presence might easily be overlooked in a casual survey of the formation. It is a perennial and is an index of mesophytic conditions. Astragalus, with its racemes of violet-purple flowers, is easily marked in the formation. While generally distributed, its abundance is sparse to subcopious, yet frequently it assumes a gre- garious habit. It is a perennial of thickened tap roots which branch above and eventually fragment behind, establishing new individuals. Its migration is slow; dispersal is effected mainly by gophers, which store the fruits for winter consumption. However, ecesis is very certain. Vernal floral aspect Toward the last of the first or the beginning of the second week in May there is a floral outburst inaugurated by the blooming of Notho- — calais cuspidata and Lithospermum angustifolium, closely followed by Castilleja sessiliflora, Lithospermum canescens, Viola pedatifids, and Oxalis violacea, which marks the inception of the vernal floral aspect. Forms are now progressively added up to about the first week of June, when the aspect is distinctly terminated by the general blooming of certain sod-formers. Astragalus crassicar pus and Rani culus ovalis have extended over into this aspect, the former reaching its maximum flowering about the second week in May, thus entering conspicuously into the vernal period. The fruiting scapes of Pet cedanum nudicaule enter into the tone, while Antennaria campesiris a with its white fruiting heads is now more noticeable than earlier. A The deadened brown tone of the prevernal aspect is at last relievee < and replaced by the green of the grassy sod, which is rendered some what bizarre by the very general distribution of some twenty-eight : flowering forms, the largest number occurring in any aspect. floral facies is developed except in the case of Poa pratensis at bar : base of slopes, and then only in the later part of the aspect. of the prairie annuals have by the later part of the aspect - 1908] peared and those of the following aspect are now all ready to bloom. Much growth has taken place in the summer perennials and they have apparently outstripped the autumnal forms. Together they overtop the majority of the vernal group, and toward the end of the aspect the large cauline leaves of Solidago and Helianthus of the autumnal aspect render many of the low-statured bloomers quite hidden, except in the very open associations on the highest slopes and crests. Four ruderals bloom in this aspect but have little influence on the formation. The summary clearly indicates the sig- nificant climatological facts. Physiological activity ensues practically throughout the aspect; the temperature range of 31° C. to 2° C., with a mean of 16° C., rarely inhibit- ng growth. The wind is dominantly from the south and east quarters. It reaches during this aspect a less total movement and so a less mean hourly velocity than in the prevernal, but the atmosphere has a much lower relative humidity; the relative ‘vaporation is thus nearly twice as great. Couple this with the highest light intensity (-704) and the beneficial results of 8.19°™ of Precipitation on twelve days are much re- duced. -- The. chresard shows a marked decrease from 14.1 per cent. on May to to 7-4 per cent. on May 22, though the average chresard for the aspect is 10.7 percent. The base (1 2.7 per cent.), slope (14.6 per cent.), and crest (8.8 per cent.) on May 22 still Showed a distinction of position is less marked than in ~ the prevernal aspect. gradation in holard, though the. VERNAL CLIMATOLOGY HARV EY—PRAIRIE-GRASS FORMATION 93 a NOILVAOAVAT ps HAILVTAY | ALIGINOH Ae HAILVTay NVA | S pzesary9 ss upayy “ a | : °o BH} prpe | & uvey{ 4 BR sales bet ° BS PrBloy a ursyl st H Aysuaqut o aanepay | ty bi ques ied oe) g aurysun: ~ s Fysans ssourpnop . uenW | g 2] mot | 00 z § < i) Fo MB is pal 5 Oe Shur "| fypopa | ApINOp{ a eB yuour a4 = } -9AOUL [eJOL, Ne = wonserp ; - Suyreastg = S) mweW | oS -_— | a Boy P 2 wmurrunyy ed a | “ a Bi raesee es eH . O — wnUIXeyy | on 94 BOTANICAL GAZETTE [AUGUST SPECIES OF THE VERNAL FLORAL ASPECT -Factes.—Poa pratensis} (base of slopes and in depressions). PRINCIPAL SPECIES.—Spiesia Lamberti sericea, Sisyrinchium angustifoliumy, Antennaria campestris,*} Spiesia Lamberti, Castilleja sessiliflora. SECONDARY SPECIES.—Viola pedatifida,t Oxalis violacea,t Lithospermum canescens, Carex Meadii,} Meriolix serrulata, Hedeoma hispida, Plantago Purshii,f Antennaria neodioica,} Lithospermum angustifolium, Oxalis stricta, Carex festucacea,} Polygala alba, Poa compressa,} Astragalus crassicarpus.*} TERTIARY SPECIES.—Pentstemon gracilis, Nothocalais cuspidata, Linum rigidum, Lappula texana, Astragalus plattensis, Gaura coccinea, Senecio platten- sis, Psoralea esculenta, Vicia linearis, Osmodium molle, Astragalus hypoglottis, cucullata UDERAL SPECIES.—Lepidium virginicum, Melilotus officinalis,t Melilotus oy Fg — Lappula. zk ET pe + Forming associations. The first week in May is marked by the flowering of N othocalais cuspidata and Lithospermum angustifolium. The solitary yellow head of the false calais, frequently 5°™ in width terminating a long (20 to 30°) naked scape, makes it very conspicuous, though it is never more than sparse to subcopious. It is largely confined 1 loosely sodded ridges and high slopes, and is pronouncedly of xef0- phytic tendencies. It is perennial by an excessively thickened rot. The achenes are heavily provided with pappus, assuring a wide dissemination. é : Nothocalais has scarcely bloomed before the puccoons are ™ flower, L. angustifolium appearing several days before the hoaty puccoon (L. canescens). The former with its terminal leafy raceme of light-yellow flowers and its sparse occurrence remains an incol spicuous element. The hoary puccoon occurs throughout with the other, but more abundantly. Its orange-yellow flowers in a compact leafless umbel make it perhaps the most conspicuous though it soe the most abundant element in the vernal aspect. Both of the puccoons are abundantly pubescent and in their structure and distribution show marked xerophytic tendencies. They are perennials by deep thick roots. The smooth nutlets preclude all but a very limited migration. Castilleja sessiliflora, Viola pedatifida, Oxalis violacea, SY rinchium angustijolium, and Spiesia Lamberti sericea bloom Be a 1908] HARVEY—PRAIRIE-GRASS FORMATION 95 gressively during the second week of the aspect, and together produce a very noticeable change in the floral tone, a change which is further accentuated by the forms that occur later. The yellow tone given by the puccoon becomes dotted here and there by yellow, blue, violet, white, and purple, and a bizarre tone is the result. Castilleja occurs rarely and of a very restricted distribution, being confined to associa- tions upon upper slopes, where its pale-yellow flowers render it always inconspicuous. The thickened perennial roots are parasitic upon the roots of other plants. Many flowering stalks may arise from one toot, thus assuming a bunch habit. The high immobility of the seeds, resulting in a very restricted distribution, accounts for its gregarious habit and local occurrence upon the prairie. Viola pedatifida with its bright-blue flowers and unrestricted dis- tribution and sparse to subcopious abundance exerts a characteristic effect on the vernal tone. The prairie violet is a perennial from a fleshy short rootstock. Oxalis violacea seems somewhat restricted to middle and lower slopes, where it may occur denscly in open, matlike patches, resulting from a slow centrifugal migration through bulb formation coupled with : positive ecesis, Though acaulescent and of low stature, its grega- rious habit and rose-purple flowers, with their green background of palmately trifoliate leaves, make it-in restricted plots of primary floral importance in the aspect. It likewise occurs sparsely but generally distributed over all parts of the formation, with the exception of ‘rests and Poa sod, where it exerts only a minor effect. The shallow ei brown bulbs indicate its perennial nature. Dissemination is ie pi the few seeds formed being not distantly ejected from a. a ocular ovary by the recurving of the loculicidally dehiscing - In this we have a still further explanation of its gregarious y. oe btagae by ' general distribution, a subcopious abundance, and whit eneh-habit’” of growth which aggregates its many blue nence ; € towers, Sisyrinchium angustifolium becomes of first promi- Clea vernal floral aspct. It is perennial by short fibrous OCKS. It is abundantly fertile, and the smooth ovoid seeds are di ot but weakly by the loculicidally dehiscing tricarpellate 96 BOTANICAL GAZETTE [AUGUST The stemless loco-weeds, S. Lamberti and its somewhat earlier flowering and more abundant silky variety, S. Lamberti sericea, are acaulescent perennial herbs from thick deep roots. Their dense spikes of dark-purplish flowers borne on long peduncles, a restricted though subcopious distribution upon the higher slopes, and silky pubescence make them very conspicuous, easily dominating in the aspect. The middle of the aspect is controlled by the variety, but the type, which flowers some ten days later, holds the floral dominance for the remainder of the vernal aspect. The type is decidedly more mesophytic in its structure and distribution, and it seems evident that the variety is very possibly a xerophytic mutant of S. Lamberi. — Propagation occurs through fragmentation of the perennial root, pro- ducing as in Astragalus a gregarious habit. A limited seed dispersal furthers this patchy distribution. Noteworthy on account of their rarity in the aspect are Astragalus platiensis, A. hypoglottis, and Viola cucullata, all flowering toward the end of the second week in May. ‘The Astragali occur only in opel association toward the crest and are strikingly inconspicuous. ‘They are both decumbent and perennial. The two-valved pod of 4: plattensis is fleshy and dehiscent and its seed dispersal is accomplished through limited propulsion. Viola cucullata is noteworthy, as only single individual has been recorded in the area and that on the middle slope of a northwest exposure, doubtless the result of fortuitous dis tribution. : The third week is characterized by the blooming of Antennari@ neodtoica, Carex Meadii, C. jestucacea, Vicia linearis, Senecio plat- tensts, and Pentstemon gracilis, Early in the third week Antennari@ neodioica flowers; it appears to be more mesophytic than A. campes- tris, occupying the lower slopes, and it occurs less abundantly, but with the fruiting scapes of the earlier species the antennarlas = scarcely second to any forms in conspicuousness. A. neodiowd ef stoloniferous perennial and forms mats, its rosettes living over wie It is easily distinguished even at a distance by its large and lighter colored mats, and by the fact that it flowers while the other species is undergoing maturation and distribution. The carices appear at about the same time toward the last of = week. C. Meadii, however, is earlier and occurs sparsely of lo 1908] HARVEY—PRAIRIE-GRASS FORMATION 97 slopes and is found inclusive in Poa sods. C. festucacea occurs likewise on lower slopes, but more abundantly and assumes the “bunch-habit” of growth. Both the carices perennate and propagate vegetatively by rhizomes. They contribute little if any to the floral tone of the aspect. Florally associated with the carices, as just noted, are Vicia linearis, Senecio plattensis, and Pentstemon gracilis, to which are soon added Lappula texana and Plantago Purshii. Vicia occurs rarely, is con- fined to lower slopes, and exerts no tone effect; it isa perennial form and is pollinated by bees. Senecio, also of rare occurrence, seems to be confined to mesophytic portions of the formation. It is conspicu- Ous On account of its numerous yellow heads and ray flowers. But for its limited occurrence it might easily dominate the tone, and in the vicinity of Sioux City it was recorded as controlling the aspect. The achenes are provided with a copious pappus and a wide distribu- tion is assured. It is a perennial, and its scarcity seems to indicate that it is of decidedly mesophytic tendencies; it may be considered Prophetic in our area. Pentstemon gracilis, though rarely a com- Ponent in any plot, is an interesting form. It is confined to the mesophytic portions of the prairie and has been noted as abundant m Western Iowa. Its rarity in our area is explained as in the case of Senecio ; it is a perennial, and its smooth though numerous seeds are limited in their distribution. Lappula texana, the hairy stick-seed, 's also a minor element, occurring mainly on lower slopes in sparse eee. It is much branched and its numerous small blue “rs exert but a restricted effect. It is an annual and very fertile, — esi nutlets whose margins are each bordered by a temas of bristles with recurved tips; distribution 1s entirely by The at It continues to bloom well into the estival aspect. HR, tele Plantain, P. Purshii, is a woolly annual whose indetermi- habit it some 20°", Of copious abundance and of gregarious is a becomes conspicuous at short distances. Its the early hagas up the spike, reaching the maximum in immobile seed at aspect and continuing well into July. Its highly account . Prevent other than a limited distribution, thus readily ng for its gregarious habit. © fourth week of the aspect, about the last week in'May, is 98 BOTANICAL GAZETTE [AUGUST remarkable for the general flowering of Poa pratensis. P. compressa is associated, but occurs sparsely and principally upon the upper slopes. The relative place of these two forms has been hard to deter- mine, but it seems that P. compressa occurs as a forerunner of the bluegrass. In its distribution P. pratensis is confined to depressions and lower slopes, and is always indicative of the highest soil-water content, the most favorable exposure, and richest humus. In these situations it forms a dense sod, frequently exclusive, which is con- stantly pushing up the slopes replacing the bunch-grasses, outlying individuals frequently reaching the higher slopes. It is perhaps one of the most mesophytic of prairie forms, and is almost invariably the forerunner of the prairie shrubs, Symphoricarpus occidentalis Rhus glabra. It reaches its highest development on the northwest exposure, and it is up this exposure that the flood-plain and ravine forest of this region has made its greatest advance upon the prairie. Poa is the first facies to bloom, but as noted above is of restricted distribution. It isa perennial and propagation is rapid by the abul- dant rootstocks, which leads to dense sod. With the bluegrass are successively added Ovxalis stricta, Linum rigidum, and Polygala alba. Never very abundant and of low stature, they add but little to the tone of the aspect, as they are OV topped by the oncoming facies of later aspects. Oxalis appears ? lower slopes, possessing frequently a gregarious distribution. It may be either annual or perennial. The few seeds are restrictedly dis- persed by the dehiscing capsules. Linum is a decidedly xerophytic annual, being a relict of earlier stages. It appears in the open 59 ciation on the upper slopes and along prairie crests. It is mee common and its fugacious petals prevent all but entire inconspicu- ousness. Its seeds are few and their mobility little. Polygala sparingly distributed over the lower slopes of prairie knolls, always working up to higher positions with the increase of mesophyti¢ conditions, but it never remains in the Poa sod. It is perhaps - of the best indices of progressive mesophytism among the prairie species. It is a perennial from woody rootstocks. Seeds are borne two in a capsule and migration is very slow. : As the vernal floral aspect is drawing to a close, several minor elements bloom, extending vernal floral activity over into t he first | | 1908] HARVEY—PRAIRIE-GRASS FORMATION 99 few days of June. Gaura coccinea, Meriolix serrulata, Psoralea esculenta, Hedeoma hispida, and Osmodium molle now progressively appear. Though flowering during the transition from vernal to estival aspect, these forms reach their maximum display during the early estival; particularly is this true of Meriolix, Hedeoma, and Osmodium. They should be considered transitional species, which appear during the unsettled climatological conditions between the vernal and estival periods, and are not specially indicative of either. Of subcopious occurrence and largely overtopped by leafy stalks of autumnal forms they must be ranked as almost neutral in the floral aneet Gaura coccinea is a relict of more xerophytic stages and occurs primarily though sparsely in the open association of upper slopes and crests. It is an annual and a low and obscure element. It bears a few-seeded indehiscent nut of little mobility. Meriolix may also be considered as a relict of the xerophytic stages of the prairie, having its present distribution limited to the open association along “rests and upper slopes, where it frequently occurs subcopiously. Its large yellow flowers make it conspicuous, but only at short range, . a. stature relegates it to a sublayer. It is a slightly shrubby oe from a woody root, producing numerous seeds which are floral ek Immobile. It continues blooming up into the autumnal is Fire tie = reaches its maximum in the early estival. Psoralea inconspicy solitary occurrence on middle slopes; add to this its iG E fading-blue flowers and it is scarcely seen upon the techies ; . observer. It is a perennial from a large edible close to the ” ‘rous root. In the autumnal aspect, breaking off lematical Alea It becomes a tumble-weed. Its rarity 1s a high, ieee nay a low annual, scarcely ever more than 20° middle slo — = oplously and not infrequently copiously upon hide its en ts low stature and leafy branches completely spicuous, ee small blue flowers, rendering it ever incon- the whole ee See Otate sparsely though quite generally over @ perennial ae. with the exception of the very crests. It is Scorpioid tacem several Stalks, terminated by leafy, pendent, It ig ‘a ae es of greenish flowers, arising from a thick root. mobility, unnoticeable. The smooth nutlets possess limited 100 BOTANICAL GAZETTE [aveust The estival floral aspect a Marked by a conspicuous decrease of the vernal floral display, a — decided climatological change, the flowering of certain sod-formers — initiated by Panicum Scribnerianum and followed by Koeleria cristala — and Stipa spartea, and the rapid addition of several prominent estival — flowers, which all results in a complete shift of the floral tone, the estival floral aspect begins toward the last of the second week in June and extends well up into middle July, when it is terminated by 4 climatological and floral change even more pronounced. | Toward the end of the vernal aspect the leafy stalks of oncoming — facies render the floral tone weak and in places drown it in a.seadl dark green; however, the estival forms like Erigeron, Delphinium, . Brauneria, Ratibida, Kuhnistera, and others seem to push rapidly : above these, forming a higher floral stratum than the vernal, but 0 — be overtopped later on by the still higher stratum of autumnal forms. — With the shifting of climatological conditions, which is VY _ generally appreciated, comes the blooming of Rosa arkansana, Enig- eron ramosus, Delphinium carolinianum, and Brauneria pallida, which with the sod-formers noted above are always indicative of the = inception of the estival aspect. The physical factors of the soil have become less contrasting on the various slopes and between different — positions on the same slope; still the south exposure seems slightly s earlier. The middle and base of slopes closely approach in absolute water content and are less separated from the crests in this respect than in earlier aspects. Correspondingly there appears 4 more uniform plant-covering at this time. It is to be noted that the holard is markedly much lower than in the vernal aspect. _ as During this time Solidago, Helianthus, and Aster have become vegetatively of primary importance and give the general tone of ars . green to the aspect. Extending over from the vernal aspect a largely occurring on the upper slopes are Polygala alba, which 0° 3 account of its indeterminate inflorescence blossoms throu - : the entire estival aspect, Meriolix, and Gaura coccinea. Hedeom ee and Ovxalis stricta continue blooming on the middle slopes: a dominating species added in this aspect are Koeleria cristata, ©” a bida columnaris, Symphoricarpus occidentalis, and Verbena Siritl — The floral forms added in this aspect are twenty-one in number, 1908] HARV EY—PRAIRIE-GRASS FORMATION less than appeared in the vernal aspect. It should also be noted that six new ruderals areadded. Panicum capillare and Hordeum jubatum not infrequently attain no small significance. The latter frequently estab- lishes in waste situations exclusive associa- tions. Its permobile awned spikelets being readily carried by wind or animal, its migra- tion is rapid. In the autumnal aspect P. capillare becomes detached at the surface, and the large and profusely branched panicles go tumbling over the prairie until lodgment Stops the distribution. In addition to the floral delineation of the vernal. The average hourly wind velocity 1S 0.9 less and the relative humidity 3.4 lower, the lowest of any aspect. Coupled wah: these conditions is the fact that the relative evaporation is 1.6 higher, the greatest “vaporation of any aspect occurring in the estival, : The holard has a slight rise in the aspect ue to the heaviest mean daily rainfall of the season. The chresard thus rises to 11 per fent. on June 6 to fall to 8.9 per cent. on June ~ 22 and 6.5 per cent. on Jul On June 22 distinction of ic : Ri the base, slope, and crest registering holard of 15-9, 16.1, and 16.6 per cent. position seemed nearly elimi- ESTIVAL CLIMATOLOGY IOI a NOLLVHOdVAR a aauviay | ALIGUYOH ~ FALLV1Ga NVAST "4 oS Iesaryo RS eee a a) 8 sepa | OS ae oe ™ So pie[o uRayy > Aysuaqut rae “ampPy | Bi *yuao sod Yo) S ww = aurysung ssourIpnoyo ae uBayy + 5 o rol | a § Ei A[rep uvayy 2 sieq | AqDopa “s “Apmopy | 99 8 quow 3 -saomrejoy, | 2 4 é | nm 3 nas ' 3) : CREO | 9 3) —— % 102 BOTANICAL GAZETTE [AUGUST respectively. Yet the average chresard for the aspect (8.8 per cent.) shows a steady decrease from that of the vernal (10.7 per cent.). SPECIES OF THE ESTIVAL FLORAL ASPECT Factes.—Koeleria cristata,t Poa pratensis.*t PRINCIPAL SPECIES.—Ratibida columnaris,t Amorpha canescens, Erigeron ramosus,{ Symphoricarpus occidentalis,t Verbena stricta,t Festuca octoflora.f Euphorbia marginata, Potentilla hippiana, Plantago Purshii,* Hedeoma hispida,* Polygala alba,* Hedeoma hispida.* TERTIARY SPECIES.—Stipa spartea, Aristida purpurea, Allionia linearis, Acerates viridiflora linearis, Osmodium molle,* Anemone cylindrica, Physalis heterophylla, Gaura parviflora, Gaura coccinea. RUDERAL sPECIES.—Hordeum jubatum, Ixophorus viridis, Panicum capil lare, Melilotus alba,* Lappula Lappula,* Verbena bracteosa, Allionia nyctaginea, Potentilla monspeliensis, Melilotus officinalis,* Lepidium virginicum.*. * From earlier aspect. + Forming associations. Koeleria cristata is a perennial bunch-grass and a very important sod-former, and may be considered one of the forerunners of the blue- grass. It occurs generally distributed higher up the slopes, where not infrequently it may reach facial rank. Above it seems to be encroach- ing upon the grama and buffalo grasses and so is quite lacking # the crests. Panicum Scribnerianum is likewise a perennial of the bunch habit and is closely associated with Koeleria in distribution, but never appears so abundantly as to become a facies. It is evi dently more of a mesophyte than the latter and follows it up the slopes. In the formation studied it is mostly confined to the lower part of the middle slopes. It blossoms slightly before Koeleria. Stipa spartea is likewise a bunch-grass and the most xerophyti¢ these three grasses. It is sparsely distributed upon the uppermost slopes and crests and never forms a facies. It must be rated as unimportant element in sod-establishment in the formation. Almost coincident with the sod-formers listed above, blooms the prairie rose, Rosa arkansana. It is the first woody perennial to bloom and is distributed over upper slopes and crests where in the lett habitat it commonly becomes copiogregarious. Its abundanc® large pink flowers, general anthesis, and height make it always a : : ae | | 1908] HARVEY—PRAIRIE-GRASS FORMATION 103 of the most conspicuous elements of the early estival aspect. Its prominence, however, is of passing duration, as the petals fall after several days and it passes into obscurity. Mobility is limited, result- ing largely in the gregarious distribution. With Rosa, blooms Del- phinium carolinianum. It is a perennial with a thick heavy root- stock, and occurs sparsely as a xerophyte inthe open association upon upper slopes and crests. It is closely associated ecologically with the bunch-grasses and invariably seems to follow them. Its single erect stalk, some 6 to 84" high, bears a large terminal raceme of con- spicuous white flowers. Rising thus so conspicuously, these plants seem like sentinels of the prairie and a few individuals are noticeable at some distance. Many seeds are produced, but mobility is slight. The anthesis of Erigeron ramosus usually precedes that of Del- phinium but follows that of Rosa, only a day or two separating them. Erigeron is a perennial or annual occurring along upper slopes, where it assumes a copiogregarious habit of growth. It seems quite restricted, few scattering individuals being noted. It is some 7 or 8™ high, with several stalks rising from a single root, which are terminated by spreading corymbs bearing numerous flowers with yellow disks and abundant white rays; thus it is very conspicuous. The achenes are provided with a double pappus, but mobility would seem limited, judging from the gregarious tendency of distribution. Brauneria, though occurring sparsely upon the highest slopes and Crests, is one of the most conspicuous early estival bloomers. It is a Xerophytic perennial with a large thick root. A single stalk, some 7 or 8™ high, is terminated by a single large head of flowers frequently sm across. The numerous long pinkish ligulate ray-flowers surround a large reddish-brown hemispheric head bristling with abundant Toughish chaff; in all a very prominent structure. The achenes are ‘towned with a short-toothed pappus, thus insuring mobility, though of @ low degree. It is to be noted that Brauneria has a blooming od of nearly two months, so it remains a conspicuous element €ven into the following aspect. : Scarcely have these forms flowered, when two species of secondary ele begin to make their contribution to the floral aspect, ming progressively during the earlier part of the third week of June, They are Anemone cylindrica and Physalis heterophylla. 104 BOTANICAL GAZETTE [AUGUST These two perennials add little or nothing to the tone of the aspect, as they are of sparse occurrence and decidedly inconspicuous. Ane- mone occurs rarely though widely on upper and middle slopes. Physalis is of rare occurrence on lower slopes, but would be noticeable — except for the pendent inflorescence which hides the yellow flowers beneath the leaves. The former rises some 50 to 60°™, with its exposed cylindrical head of numerous woolly achenes, which are subject to wide dispersal. The immobile fruit of the latter and its ventral position cooperate to insure a very restricted dissemination. The last days of the third week and early part of the fourth are _ marked by the general flowering of three forms, Ratibida columnaris, Sym phoricar pus occidentalis, and Verbena stricta, all of primary impot- tance. Gaura parviflora, Linwm sulcatum, and Allionia linearis, three flowering forms of minor significance, are added at about the same time. Linum is an annual some 4o™ high, occurring sparsely upon the lower slopes. Its humble place in the floral tone is largely due to its limited occurrence, for its yellow flowers (1.5°™ in diameter) would otherwise make it a notable element. Gaura is noteworthy — mainly as a matter of record, a few specimens only being noted 00 the middle slope of a northwest exposure. It is an annual and : : frequently reaches a height of 1™ or more. Allionia is a perennial occurring rarely upon middle slopes. The straw-colored involucre incloses one to three small purplish flowers and it is always of minor fe prominence. The anthocarpous fruit has little mobility. About this time are also added two sod-forming species, Festuca octoflora and Aristida purpurea. Aristida is of rare occurrence and com tributes little to the floral aspect or plant covering. Festuca, 00 the other hand, is a sod-former of some significance upon lower and middle slopes, being easily replaced however by Poa, which seems to follow it. It is apparently a pioneer form, taking rapid possessiO? of available ground in the open association by means of its heavy; thick, matlike sod. In Ratibida the long yellow ligulate ray-flowers first spread about June 20, but it is not until several days later that there is a gene display and the tube flowers of the columnar disk begin to open. They flower first in a band at the base of the indeterminate head, progressing up at the rate of about 3 to 5™™ aday. The plants ar° f 1908] HARVEY—PRAIRIE-GRASS FORMATION IO05 some 7.54" high, and each of the branches is terminated by a very striking head; yellow drooping rays, 6 to 9 in number and frequently 3™™ long, surround a deep-brownish columnar head some 4°™ high. The prairie cone-flower occurs copiously upon lower and middle slopes, extending crestward (fig. 1). In the former locations it fre- quently assumes almost facial rank and gives a bright-yellow tone to the entire floral aspect. It is a prolific and continuous bloomer, dominating the aspect through the month of July and the greater part - 1.—Late estival aspect; Ratibida columnaris upon a middle slope; the r uders! Jubatum in right foreground. Fic He ordewm of August, and extending up to the middle of September. Ratibida ‘S @ perennial from a thick root. The achenes are provided with a diminutive pappus of one or two teeth, and so lack of mobility and Sreat fertility result in its copious abundance in restricted localities. It should be recorded that a few specimens with reddish-brown ays having yellow tips and bases have been noted. a. the time Ratibida is spreading its neutral ray-flowers the PWR ®wers of Symphoricarpus appear, reaching their maximum “ting two or three weeks later. The wolfberry is of restricted 106 BOTANICAL GAZETTE [AUGUST distribution, occurring gregariously at the base of slopes and in mesophytic depressions; frequently outlying individuals are found. In the former situations it ranks not infrequently as a facies. It is the largest of the woody perennials of our area, being a profusely branched shrub frequently 1 to 1.25™ tall. It is characteristically associated with the Poa sod, which it follows in the latter’s advance upon the prairie; the most advanced occupation is upon the north . i es Fic. 2.—Late estival aspect; Symphoricarpus association in a depression . northwest exposure; Poa sod in foreground. to northwest exposures, where it also first appears (fig. 2). It is the forerunner of Rhus glabra, which in other parts of the prairie follows it closely, together making up the shrub stage, which is succeeded by the Quercus macrocarpa and Ulmus julva association as the forest pushes out upon the prairie. While the numerous axillary clus of pink flowers are not conspicuous from a distance, the mass® - dark-green leaves make the Symphoricarpus association very note’ able. Very few seeds are borne in the white globular berries; 1908] HARVEY—PRAIRIE-GRASS FORMATION 107 immobility and high ecological demands result in its gregarious habit. The berries are persistent and birds may help somewhat in dispersal, The last of this group to bloom is Verbena stricta. About June 25 the purplish-blue flowers make their appearance at the base of the long (1 5-30°™) indeterminate terminal spikes in a narrow band, which moves upward day by day at the rate of about 1 to 2°™. The maxi- mum flowering, however, seems to be reached about July Io to 20. és =. 3-—Late estival aspect; Verbena stricta determining the tone of a lower slope; © white patches are the ruderal Hordeum jubatum. Like Ratibida and for the same reason, it flowers abundantly through July brig August and into September. It has a copious and general distribution and not infrequently assumes a dominating influence etal (fig. 3) and upper slopes as well as crests. It is a per- it ‘tom a heavy root and several stalks from the same root give ci infrequently a “bunch” appearance. jo the last days of June and the first days of July, several ag to complete the estival floral aspect. In order of uphor = they are Acerates viridiflora linearis, Potentilla hippiana, ¢ marginata, and Amorpha canescens. All assume local 108 BOTANICAL GAZETTE [AUGUST importance except Acerates, reaching their maximum display in the serotinal aspect. Acerates appears rarely and as a solitary xerophyte — upon the higher slopes and along crests. It is a perennial with numerous permobile comose seeds, yet its abundance is always low. Its solitary umbel of greenish flowers, which blend with the foliage of the prairie, renders its detection difficult. Potentilla possesses a copiogregarious or a solitary distribution along the middle an lower slopes. It rises 50 to 7o°™, with the erect stems terminating in loose cymes of numerous yellow flowers. It thus exercises a local effect in the floral aspect. Through its numerous annual rosettes it also contributes in a limited degree to the plant covering. It isa perennial from a thick root. The numerous achenes are highly immobile, resulting in a limited distribution and the gregarious habit. The white-margined spurge, Euphorbia marginata, is an annual which occurs subcopiously on lower slopes and rises erect to a height of 50 to 75°". The stems bear abundant bright-green leaves and are tet- minated by three-rayed umbels whose greenish-white flowers are sub- tended by involucres of numerous white-margined bracts, making the entire umbel a very conspicuous object. Amorpha canescens is a prominent perennial shrub (50 to go°™ high) exerting a controlling influence. It is a marked xerophyte and may rise to primary rank | upon the crests in a sub-copiogregarious distribution, but rarely occurs — upon the lower mesophytic slopes. Its gregarious habit and its abun- dant and densely white canescent leaflets and densely clustered termi- F nal spikes of dark-blue flowers make it a very striking object, especialy when it occurs in such abundance. With sod-establishment it ually disappears, being a characteristic component of the bunch-grass stage. The indehiscent one-seeded pod is highly immobile. THE UNIVERsITY oF CHICAGO Te UNDESCRIBED PLANTS FROM GUATEMALA AND OTHER CENTRAL AMERICAN REPUBLICS XXX: Joun DONNELL SMITH CURATELLA AMERICANA L., var. pentagyna Donn. Sm.—Gynae- cium e carpellis 5-compositum. "gies saltem in exemplis suppetentibus solitariae vel paucifasciculatae Sa ; Sak Depart. Baja Verapaz, Guatemala, alt. goo™, Mart. t907, W. A. Kellerman (n. 6499). Capparis (§ CapPpARIDAsSTRUM DC.; Eichl.) Tuerckheimii Donn. Sm.—Omnibus in partibus glabra. Folia oblongo-lanceolata longe incurvo-acuminata infra medium angustata ima basi obtusius- cula petiolis plerumque bis terve longiora. Pedicelli gracillimi. Sepala paene sejuncta petalis 4~5-plo breviora. Discus 4-glandularis. Gymnophorium petalis 3-plo fere longius. Ovarium cylindrico- ellipsoideum uniloculare. Frutex inermis. Folia pergamentacea nitida 7-1 5° longa 3-5°™ lata, juniora subtus flavescentia costa nervisque rubiginosa venis pellucida, petiolis longitudine multum variis 2-9°™ longis ad apicem versus incrassatis, stipulis sicut eae bracteolarum elongato-triangularibus aegre 1.5™™ longis margine albi- dis. Racemus corymbosus, rhachi 2-3°" longa, pedicellis 5-13 circa 5—6.5°™ longis apice tetragono-incrassatis. Sepala ovata obtusa 3-3.5™™ longa retroflexa. Disci glandulae carnosae. Petala lutea elliptica 14-15™™ longa 8™™ lata. Sta- mina numerosa 28™™ longa, antheris oblongo-ellipticis 3™™ longis. st aa 4-4.5°™ longum, ovario 5™™ longo spurie 3~5-loculari. Baccae defici Inter rupes prope Panzal, fe as Baja Verapaz, Guatemala, i 1200™, 1746). Eurya (6 FREZIERA oe guatemalensis Donn. Sm.—Folia supra lucida subtus ferrugineo-tomentosa integerrima oblonga vel lanceolato-oblonga acuminata basi inaequali acuta vel subacuta, nervis lateralibus creberrimis. Flores pedicellati in fasciculam pedunculatam aggregati. Petala glabra porrecta ovata apice obtuso patula sepalis tomentulosis bis longiora. Ovarium elongato-coni- cum. t Continued from Bor. GAZETTE 44:117. 1907. 109 ] [Botanical Gazette, vol. 46 I1o BOTANICAL GAZETTE [AUGUST Arbor, ramulis subflexuosis, novellis sicut petioli et inflorescentiae ferrugineo- tomentulosis. Folia subcoriacea 1o-17°™ longa 3-5°™ lata supra in sicco laete See costa nervisque supra impressis subtus prominentibus, his inter tantibus cum intermedio tenuiore brevioreque alternantibus, petiolis 12-14™m siti S margi saniad estar gh a inflorescentias paulo superantibus. Pedunculi crassi deciduo-bracteosi 4-7™™ longi, pedicellis 5—7 circiter 4™™ longis basi bracteola fultis, floribus as longis. Sepala cum bracteolis paulo minoribus suborbicularia concava ferrugineo-tomentulosa. Petala vix cohaerentia y pases pyramidatum stigmatibus carens. Floris feminini filamenta antheris plus minus breviora, ovarium glabrum triloculare petalis bis brevius in stylum 3-fidum sensim attenuatum. Bacca eee satis matura conica stylum subulatum aequans.—E., sericeae Szysz. proxima. Collium in declivibus aridis prope Cobdén, Depart. Alta Verapaz, Guate- mala, alt. 1350™, Jun. 1907, H. von Tuerckheim (n. IE. 1824). Picramnia brachybotryosa Donn. Sm.—Foliola 11-1 5 plus minus dissociata praeter nervos subtus puberulos glabra obtuse contracto- acuminata, superioribus oblongo-ovatis, inferioribus ovatis, terminali lanceolato-elliptico. Racemi foliis breviores, masculini brevissimi, floribus apetalis tetrameris nonnunquam trimeris glabris. Fruticulus (e scheda Tuerckheimiana), ramulis petiolis racemis leviter pubes- centibus. Foliola per paria deorsum decrescentia petiolo communi 16-24°™ longo instructa exmucronulata, superiora 7-9°™ longa basi inaequali obtusa, infima 3-4.5°™ longa basi subtruncata, terminale remotum basi acutum, petiolulis lateralibus 2-3™™ longis. Pedunculus masculinus lateralis 2°™ longus racemos Racemi feminini terminales bini 16-18°™ longi, pedicellis solitariis remotiusculis 3-6™™ longis glabris, calycis segmentis 3-4 triangularibus vix ™™ longis, ovario ellipsoideo 1.5-2™™ longo digyno. Bacca ignota—Haec a ceteris speciebus tetra- ris adhuc cognitis est secernenda, differt enim a P. tetramera Turcz. sesieals nimis brevi) saltem foliolis inflorescentia calycibus, a P. quaternaria n. Sm. imprimis floribus apetalis. ee silvis prope Coban, eras Alta Verapaz, RB Csee alt. r550™, Jun. 1907, H. von Tuerckheim (n. II. 1801). PACHYRHIZUS ANGULATUS Rich., var. tanevtinias Donn. Sm. —Foliola integerrima subrhomboidea vel inaequilateraliter sub- rhomboidea sursum acutissime incurvo-elongata infra medium in angulum fere rectum sensim angustata subtus appresse pilosa nervis ferruginea. 1908] SMITH—PLANTS FROM CENTRAL AMERICA IIL Foliolum terminale 63-84™™ longum 38~52™™ latum, lateralia 55—71™™ longa 28-40™™ lata. oban, Depart. Alta Verapaz, Guatemala, alt. 1350™, Mart. 1907, H. von Tuerckheim (n. II. 1671). Dalbergia (§ Stssoa Benth.) tucurensis Donn. Sm.—Foliola 11-15 oblongo-ovata vel ovata apice acuta et mucronulata basi acuta vel obtusa subtus pallida et minutissime fusco-reticulata. Paniculae axillares foliis bis breviores laxe ramosae. Calycis lobi 4 superiores rotundati infimo acuto bis superati. Stamina g monadelpha. Ova- rium pilosum. #455 ee pees } 4s] Arbor, ramulis junioribus pet Folii petiolus communis 21-30°™ longus, folicla remote alterna 62-10g™ longa 40-48™™ lata, petiolulis 3™™ longis. Paniculae subpyramidatae pedunculus 3-4°™ longus, rami 5~7 remoti, inferiores ramulis computatis 4-5°™ longi, pedicellis 1-2™™ longis, floribus 6-7™™ longis. Calyx 5™™ longus usque ad or loba- tus, lobis 2 summis alte connatis quam ceteri bis latioribus, infimo eolato tubum superante. Petala calyce paulo longiora, vexillo ements Stamen vexillare constanter deficiens. Ovarii stipes stylo bis longior. Concepcién prope Tucurt, Depart. Alta Verapaz, Guatemala, alt. rooo™, Apr. 1907, H. von Tuerckheim (n. II. 1712). Miconia (§ Eumiconia Naud.; Glomeratiflorae Naud.) oligoce- phala Donn. Sm.—Folia satis disparia lanceolata utrinque acuta supra glabra et albido-punctulata subtus cano- et stellato-tomentulosa 3-5-plinervia calloso-denticulata. Paniculae rami simplices in apice vel prope apicem 1- aut 3-capituliferi, floribus tribracteolatis. Ramuli Hi | f i et stellato-tomentulosi. Folium in eodem jugo majus 10-19°™" lonstim paulo infra medium 3-4°™ latum alterum triente usque ad bis superans, petiolis 8-18™™ longis. Panicula aaa foliis brevior, ramis superioribus unicapituliferis, infimis quaternis prope a capitula 2 adjecta sessilia ferentibus, capitulis semiglobosis 5—8-floris, baat ellipticis 3™™ longis, floribus 5~6-meris 9™™ longis. Calyx companulatus 5™™ altus, lobis semioribcularibus scariosis tuberculo r™m longo extus appendiculatis. etala obovato-oblonga 4™™ longa. Stamina 6™™ longa, antheris uniporosis. Bacca depresso-globosa 3™™ lon Cob epart. Alta Veena, Guatemala, alt. 1550™, Aug. 1904, H. von Fuerchheim, n, 8686 ex Pl. Guat. etc. quas ed. Donn. Sm. (sub Conostegia lanceolata Cogn. olim distributa): Maj. 1907, H. von Tuerckheim (n. II. 1781). Miconia (§ CREMANIUM Benth. et Hook.) purulensis Donn Sm.— Simpliciter furfuracea. Folia oblongo-elliptica incurvo-acuminata 112 BOTANICAL GAZETTE [aucusT basi acuta integra 5-nervia supra glabra subtus nervis furfuracea. Flores pedicellati 5-meri glabri. Antherae biporosae. Ramuli obtuse tetragoni cum petiolis foliorum subtus nervis panicula fulvo- furfuracei. Folia chartacea plerumque satis disparia 11-20°™ longa medio 5-9°™ lata nervo utrinque arcte submarginali tenui computato 5-nervia, petiolis 3-7°™ longis. Panicula late pyramidalis pedunculo 2.5° longo adjecto 11-14°™ longa congestiflora, ramis ramulisque 2-4-nis, pedicellis o. 5-1.5™™ longis, flori confertis 4.5™™ longis. Calyx hemisphaericis 1.5™™ altus, dentibus obtuse deltoideis tuberculo punctatis. Petala orbicularia 1 .5™™-diametralia. Stamina 3™™ longa, antheris rectis oblongo-cuneatis 1™™ longis, connectivo infra loculos non Sintbacts supra medium geniculato. Stylus in floribus scrutatis nullus. Bacca desideratur. silvis circa Purul4, Depart. Baja Verapaz, Guatemala, alt. t800™, Apr. 1907, H. von Tuerckheim (n. Il. 1718). Clidemia (§ SaGRAEA Cogn.) diffusa Donn. Sm.—Folia oblongo- ovata incurvo-acuminata basi leviter cordata vel rotundata 5-nervia subintegerrima setuloso-ciliolata. Thyrsi longissimi, ramis remotis uti pedunculus rhachisque filiformibus et ramulis divaricatis, pedi- cellis brevibus, floribus 5-meris. Calyx campanulatus glaber, denti- bus externis minutis. Ramuli teretes et thyrsi sparsim patenterque pilosi purpurascentes, Folia branacea in eodem jugo leviter inaequalia 85-125™™ longa 35-6o™™ lata, petiolis supra aoa a 25-50™™ longis. Thyrsi ex una axilla orti dependen- tes pedunculo 4-5°™ longo — 16-19°" longi ter quaterve trichotomi, rhachis ee 35-55™™ longis, axibus secundariis inferioribus 20-25™™ longis, tertiariis 5-6™™ longis, pedicels 1-3™™ longis, floribus 6™™ longis. Calycis rubiginosi tubus 2.5™™ longus, dentibus deltoideis denticulo o. 1 Sagas appendiculatis. Petala flava obovata 3™™ longa staminibus paulo ongiora. Ovarium vertice conicum, stylo 4™™ longo. Bacca globosa 3™™- diametralis.—In sectione floribus constanter 5-meris anormalis. In monte silvestri prope Purul4, Depart. Baja Verapaz, Guatemala, alt. 1800™, Apr. 1907, H. von Tuerckheim (n. IL. 1717). Centropogon (§ SyPHOCAMPYLOIDES Benth. et Hook.) calochlamys Donn. Sm.—Glabra. Folia lanceolato-elliptica utrinque longe acu- minata argute subcalloso-denticulata. Inflorescentia foliis superata, pedunculis racemoso-confertis paucis. Calycis lobi lanceolato- ovati tubo 4-5-plo longiores corollae tubo aliquantulum breviores. Antherae totae excepto vertice inferiorum nudae. Fruticulus simplex 22-35°™ altus. Folia membranacea 9-16°™ longa medio 3-5.5™ lata apice contracto-acuminata basi aequali in petiolum complanatum 1908] SMITH—PLANTS FROM CENTRAL AMERICA 113 to-22™™ Jongum attenuata costa nervis margine subtus sicut petiolus purpu- rascentia. Pedunculi terminales 2-5 subfasciculati nonnunquam ex axillis superi- oribus orti 3.5-6°™ longi bracteis foliaceis lineari-lanceolati 2°™ longis denticu- latis fulti. ‘Calycis tubus late hemisphaericus 3-5™™ altus, lobi 16-21™™ longi to™™ lati denticulati monente cl. repertore in vivo intense violacei etiam in sicco saturato-colorati. Corollae dilute purpurascentis tubus extus glaber intus pube- rulus 22-25™™ longus, laciniae 15-21™™ longae. Tubus staminalis pubescens 32™™ longus, antheris 7-8™™ longis, minoribus apice barbatis, omnibus ceterum glabris. Stigmata semiorbicularia 3™™ lata. Bacca semilibera depresso- et compresso-globosa 6™™ longa 9™™ lata profunde bisulcata styli reliquis apicu- lata —C. —— Robinson proximus differt insigniter calycis lobis permagnis et color: In monte ane ea Coban, aes Alta Verapaz, Guatemala, alt. 1650™, Aug. 1907, H. von Tuerckheim (n. II. 1893). Ardisia (§ IcacorEA Pax; Mez.) verapazensis Donn. Sm.—Glabra. Folia obovato-oblonga obtuse acuminata in petiolum brevem margina- tum attenuata integra coriacea pellucido- et subtus rubro-punctulata. Pedicelli subumbellato-corymbosi gracillimi, floribus inter maximos 5-meris. Sepala extus punctulata intus infra medium lepidotula margine scariosa et nuda. Corollae lobi imbricati epunctati. Fila- menta antheris aequalia. Arbor. Folia 25°™ longa 7°™ lata, nervis lateralibus primariis utrinsecus Ii-15, areolis in utraque pagina obscuris. anicula corymbiformis 15°™ longa 20°" lata, axibus robustis, pedicellis 4-6-nis 12-20™™ longis, floribus ebracteolatis. Sepala paene sejuncta dextrorsum tegentia oblongo-ovata 6™™ longa obtusa crassa. orolla ante anthesin 1r™™ Jon quartam connata purpurea, tubo 3™™ longo intus supra medium perdense aureo- punctulata, lobis orbiculari-ovatis. Stamina medio tubi corollini affixa 6™™ longa, filamentis liberis, antheris elongato-triangularibus dorso concoloribus. Ovarium epunctatum ovatum stylo 7™™ longo computato ro™™ longum. ignota.—Haec magnitudine florum ceteras species praeter A. paschalem Donn. Sm. superat. In monte silvoso prope Coban, Depart. Alta Verapaz, Guatemala, alt. 1600, Jan. 1908, H. von Tuerckheim (n. II. 2093). = Stylogyne phaenostemona Donn. Sm.—Folia inter minora lanceo- lata e medio utrinque acuminata coriacea glabra immaculata. In- florescentia terminalis, floribus 5-meris. Sepala membranacea in- tegra punctulata. Corolla ad usque medium connata, lobis ovalibus punctulatis. Stamina medio tubo inserta cum stylo bene exserta, antheris minutis. II4 BOTANICAL GAZETTE . [AUGUST Arbor, ramulis verrucosis, novellis et paniculis fusco-velutinis rubro-punc- tulatis. Folia 75-90™™ longa 28-33™™ lata apice basique ipsis obtusiuscula integra utrinque minute areolata, costa supra immersa subtus prominente, petiolis oe 4-5™™ longis. Paniculae pyramidales 50-65™™ longae tripinnatim compositae, saepe ramulos axillares brevissimos terminantes et pseudoaxillares, pedicellis ad apicem versus ramulorum subcorymbosis 3-5™™ longis, brac- teolis minutis deciduis. Sepala fere sejuncta late ovata 1™™ longa margine scariosa et minutissime ciliolata. Corolla 2™™ longa, lobis apice rotundatis cum sepalis rubro-punctulatis. Stamina 3™™ longa, filamentis liberis antheras ovatas pluries superantibus. Ovarium globosum 1™™-diametrale, stylo 2™™ longo, stigmate punctiformi, ovulis circiter 5 in placenta globosa absconditis. Fructus ignotus.—Secundum methodum cl. Mez juxta S. orinocensem Mez inserenda Coban, Depart. Alta Verapez, Guatemala, alt. 1350™, Jun. 1907, "A . von Tuerckheim (n. II. 1814). Gonolobus (§ DistemmMa K, Schum.) prasinanthus Donn. Sm.— Folia oblongo-ovata incurvo-acuminata sinu obtuso latoque leviter cordata bulboso-pilosiuscula vel glabrescentia. Cymae subumbelli- formes, pedicellis pedunculum subaequantibus. Segmenta corol- lina oblonga calycinis linearibus dimidio longiora. Corona exterior membranacea integra a gynostegio brevissimo libera. Rami cum inflorescentiis pubescentes vel glabrescentes. Folia supra fere _ ee longa 30-39™™ lata oles ad ortum limbi glandulis 2 conicis— tiolis pubescentibus 30-35™™ longis. Pendunculi 15-22™™ longi, Bedicellis ae ue 4-6 arcte approximatis 12-20™™ longis, floribus 18-22™™- diametralibus, perianthio herbacei coloris patente extus puberulo. Calycis par- titi segmenta 5-6™™ longa a basi 1.5™™ lata sensim angustata obtusa, sinubus 1-glanduliferis. Corollae tubus — segmenta 8-9™™ longa a basi 4™™ lata in apicem obtusum scariosum retro m sensim angustata nervosa. Corona exterior 0.5™™ lata glabra, interior pr sag LP seer coax | train cake Gyno- a rm longum, stigmate 4™™ lato. Folliculi nondum solum visi ves.—G. martinicenst Decne. proximus. A raternum eatiy foliis et stato accedens recedit tamen inter alia pedicellis arctius approximatis et corona duplice Cubilquits, Depart. Alta Verapaz, Guatemala, alt. 350™, ae 1904, H. von Tuerckheim, n. 8711 ex. Pl. Guat. etc. quas ed. Donn. Sm Solenophora Tuerckheimiana Donn. Sm.—Pube moniliformi furfuracea. Folia ovato- vel obovato-elliptica acuminata ad basin obtusam altero lato excisa supra tuberculato-furfuracea subtus praeter nervos furfuraceos glabra. Cymae dependentes longissimae semel bis terve 2-3-chotomae, pedunculis axibusque capillaceis elongatis. 1908] SMITH—PLANTS FROM CENTRAL AMERICA IIs Ramuli subtetragoni purpurascentes cum petiolis inflorescentiis floribus plus minus ete ceo-pubescentes. Folia membranacea plerumque parum inter-_ dum valde disparia 125—150™™ longa 68-75™™ lata nervis et margine p ae petiolis 45-65™™ longis. Cymae pedunculo 40-607™ pein adjecto floribus autem exemptis 7O-11 5™™ longae, bracteolis linearibus 6-10™™ longis, eet 18-27™™ longis. Calycis siatmmetrass tubus oblongo-obconicus mm Jongus tertia nalts ovario adhaerens, lobi deltoidei 4™™ longi dentati. Conllde totae aurantiaceae tubus aioe infundibularis 30™™ es lobi semiorbiculares 7™™ longi integri. Antherae exsertae in quadram 4™™ longam atque latam Ripsoaee Glandula disci 2™™ crassa integra. een nondum calyci accrescenti usque ad medium a In sylva profunda ase ad montem prope Coban, Depart Alta Verapaz, Guatemala, alt. 1600", Dec. 1907, H. von Tuerckheim (n. II. 2028). DAPHNOPSIS RADIATA Donn. Sm. in Bot. Gaz. 14:30. 1889.— Diagnosi adde charactera e specimine fructifero hactenus ignoto sumpta:—Fructus sessilis ovoideus 7™™ longus perianthii tubo accrescente marcido supra basin circumcisso inclusus in stylum 2™™ longum subabrupte dessinens, pericarpio carnoso.—Arborea. Coban, orks Alta Verapaz, Guatemala, alt. 13507, Maj. 1907, H. von Tuerckheim (n. Il. 1874). Pilea (§ HETEROPHYLLAE Wedd.) purulensis Donn. Sm.—Glabra. Folia inaequilateraliter subovato-lanceolata tenuiter acuteque elon- gata basi rotundata vel obtusa serrata trinervia, cujusque paris alterum petiolatum altero conformi sessili 3-4-plo majus. Dioica. Cymae masculinae in globum maximum graciliter pedunculatum glomerulatae. Cymae femininae petiolo multum breviores. Folia tenuiter membranacea supra minute lineolata subtus cystolithis desti- tuta toto fem crenulis antrorsis apiculatis serrata usque ad apicem trinervi venulis m subtus manifestis — basi saepe altero latere aeonen altero acuta, in eodem jugo folio majore 100-150™™ longo paulo infra medium 40-55™™ lato, petiolis 16-23™™ longis, ce 25-50™™ longo. Glomerulum mas- culinum ro-15™™-diametrale pedunculo 18-30™™ longo suffultum, pedicellis 2-3™™ Jongis, perigonio = longo glabro scarioso, segmentis apice herbaceis. Cymae femininae 8-10™™ longae, nlc confertis flores subaequantibus, perigonio rubro-punctulato 1. we longo, segmento intermedio cucullato ceteris longiore achenium ovale aequan In monte silvoso prope ae Ale Baja Verapaz, Guatemala, alt. 1800™, Apr. 1907, H. von Tuerckheim (n. I. 1707). Pilea (§ HETEROPHYLLAE ee ecbolophylla Donn. Sm.— Folia quam maxime disparia, alterum obovato-ellipticum vel -lanceo- 116 BOTANICAL GAZETTE [AUGUST latum caudato-acuminatum basi acutum crenato-serratum tri- aut tripli-nervium altero conformi abortivo 12-15-plo majus. Dioica. Cymae femininae petiolis bis breviores. Caules a rhizomate repente ascendentes 34™ longi simplices. Glabra. Folium in quoque jugo majus pergamentaceum opacum tantum in pagina superiore lineolatum too-115™™ longum supra medium 30-42™™ latum in caudam r5-18™™ longam serrulatam subabrupte acuminatum triente inferiore integrum, nervo utroque basali paulo infra caudam evanescente, folium alterum nanum 7-8™™ achenio ovali 0.75™™ longo bis brevioribus.—A: izobolam Migq. et P. pan- samalanam Donn. Sm. folio quasi rudimentario sient as fluminis Dolores dicti, Depart. Alta Verapaz, Guatemala, alt. 350™, Jul. ates H. von Tuerckheim, n. 7983 ex. Pl. Guat. etc. quas ed. Donn. Sm. (Sub P. pansamalana Donn. Sm. olim distributa.) Pilea (§ DENTATAE; Glabrae; Brevipedunculatae Wedd.) Tuerck- heimii Donn. Sm.—Folia lineari- vel elliptico-lanceolata sensim tenuiterque falcato-elongata basi acuta vel leviter emarginata triente inferiore integra triplinervia supra manifeste subtus subtile lineo- lata longiuscule petiolata. Dioica. Cymae masculinae petiolos subaequantes recurvae pluries laxe patenterque dichotomae, floribus dissitis pedicellatis. Caulis a basi oblique radicante erecta ramosa. Folia membranacea leviter disparia to0-160™™ longa plerumque 25-30™™ interdum 60™™ lata, serraturis antrorsis parvis apiculatis saepe ad callos reductis, nervo utroque basali paulo infra apicem limbi evanescente, lateralibus pellucidis anastomosantibus, petiolis longitudine multum variis 15-43™™ nee Cymae masculinae solum visae a nodos plerumque quaternae 25-45™™ longae, pedunculo 3-6™™ lo ongo et ramis complanatis, perigonio sibtbetfioncosd pedicellum circiter bis superante, segmentis lanceolatis minute cucullatis lineolatis, filamentis rubro- -punctulatis, antheris exsertis ovatis, connectivo rubicundo. n monte silvoso haud procul a Coban, Depart. Alta Verapaz, Guatemala, alt. 1550", Jun. 1907, H. von Tuerckheim (n. II. 18 35): PILEA RIPARIA Donn, Sm, in Bot. Gaz. 19:11.—Monoica vel dioica. Cymae unisexuales, masculinae adhuc descriptione carentes ex axillis inferioribus ortae singulae aut binae pedunculos implice vel furcato petiolum aequante suffultae pluries dichotomae congestiflorae, pedicellis gracilibus, perigonii segmentis omnibus cucullatis. 1908] SMITH—PLANTS FROM CENTRAL AMERICA eof | Folia usque ad 12~-14°™ longa 5°™ lata, petiolis r5-20™™ longis. Cymae mas- culinae pedunculo computato 4o-45™™ longae, pedicellis demum 4-5™™ longis, perigonio 3™™ longo rubro-punctulato. Ad ripas rivulorum prope Panzal, ifs Baja Verapaz, Guatemala, alt. To0o™, Apr. 1907, H. von Tuerckheim (n. I. 1708). Myriocarpa obovata Donn. Sm.—Folia glabra oblongo-obovata subabrupte cuspidata basi acuta calloso-subdenticulata inordinate lineolata vix ultra’ medium tri- aut tripli-nervia. Dioica. Spicae femininae foliis multum breviores pluries dichotomae laxiflorae, flori- bus singulis vel fasciculatis. amuli glabrescentes verrucosi epidermide in sicco ferruginei. Stipulae lanceolato-ovatae 5™™ longae pilosae cito deciduae. Folia pergamentacea opaca I0-16°™ longa supra medium 3.5-6°™ lata cuspide 8-1o™™ longa acuminata infra medium integra utrinque praesertim supra cystolithis haud radiatim dis- positis conspersa, nervis lateralibus primariis utrinsecus 2-3 arcuatis, venis reticulatis, petiolis 6-13™™ longis. acne femininae solum visae ad nodos superiores _— solitariae filiformes pedunculo 2-3°" longo computato 6-8°™ longae pilosae, floribus ciliatis uti fasciculi pauciflori sparsis, his sae breviter pedicellatis, calyculo diphyllo aegre 0.5™™ longo stipitem paulo superante. Ovarium Serge 1™™ Jongum in stylum attenuatum. Stigma ramo brevi semilun In ve mee prope San Pedro Sula, Depart. Santa Barbara, Honduras, alt. 800™, Jan. 1887, Carl Thieme, n. 5500 ex. Pl. Guat. etc. quas ed. Donn. Sm. BALTIMORE, MARYLAND A METHOD FOR THE QUANTITATIVE DETERMINA- TION OF TRANSPIRATION IN PLANTS Gero. F. FREEMAN (WITH ONE FIGURE) In plant-breeding work, which has engaged my attention for several years, a pressing need has been felt for some means of measuring the drought-resisting quality of individual plants. Morphological char- acters, such as small leaves, small and few stomata, pubescence, and thick epidermis, are characters which may be assumed to be correlated. with drought resistance in that they tend to reduce transpiration and are characteristic of xerophytic plants in general. Moreover, it may be assumed that, other characters of two plants being equal, the one having the lower rate of transpiration per unit of leaf surface would be more suited to the drier portions of the plains region or to withstanding long periods of drought in the more humid districts. Some direct method of measuring the transpiration of plants growing in the field would be of great value therefore to the breeder in selecting for the quality of drought resistance. At the beginning of our work in alfalfa breeding at the Kansas Ex- periment Station, no method was known to me which seemed to meet all of the requirements for securing data concerning transpiration for plant-breeding work. It was desired to use the plants selected as mother plants. Therefore they could not be taken up and planted, and the rate of loss of moisture determined by weight. Furthermore, on account of the very long tap roots of alfalfa, it would be impracti- cable to use a pot large enough to accommodate them without such pruning as would endanger the life of the plant, or at least make them little other than cut stems. Although it is known that the cut stems of the plant when placed in water do not transpire normally, an attempt was first made to see if the differences sought could be revealed by this method. As a preliminary study and in order to ascertain the effectiveness of the potometer method in determining these individual differences in the Botanical Gazette, vol. 46] {118 1908] FREEMAN—DETERMINATION OF TRANSPIRATION 11g transpiration rate as compared with the same plants growing in the soil, four species were selected which seemed to promise a large range of difference in transpiration. Accordingly, two individuals of each of the following species were selected from young potted plants in the greenhouse: Coleus Blumei, Chrysanthemum leucanthemum, Pelar- gonium sp., and Portulaca oleracea. The plants to be used on their own roots were repotted into glass tumblers of suitable size. This was done without disturbing the root system. Evaporation from the soil was prevented by covering the tops of the glass with a good ‘ quality of dental rubber. For the potometers the plants were cut from the pots at the sur- face of the soil, one or two of the lower leaves removed, and the stems inserted, through holes in the cork, into bottles containing tap water. The whole stopper was then carefully sealed with paraffin. Each potometer was placed by the side of its corresponding potted plant and the whole series left on a table in a well-lighted room. During the investigation, which lasted approximately sixty hours, the transpiration rate was found by weighings made at intervals of about one hour during the day. In Table I the average transpiration rate for each plant during the whole of the experiment is shown, and the transpiration rate of the plants on their own roots (normal) is compared with that of the plants in the potometer by reducing the latter to percentages of the former. TABLE I Potted plants on | Cat stems in. pot- Cut stems in oots; trans meter; transpiration) ee cent. pation i ng pe | ing prom | De cent surface per hr. per hr. transpiration Oe OEE ee 7.21 1.44 = COIR a 05s ees 2.77 0.37 13-3 Porttalacasss 3 cos eet 1:72 0.47 27-3 Geranium ood: ees, 8 0.65 0.65 It will thus be noted that there is a great difference between the average transpiration rate of a plant on its own roots and that of a cut stem of the same plant placed in water. Moreover, roughly speaking, this difference is greatest in those plants having the highest normal transpiration. This difference, however, may vanish alto- 120 BOTANICAL GAZETTE [aucust gether in plants with a low normal rate, as in the case of the geranium, A close scrutiny of Table I is sufficient to demonstrate that although the potometer will give some idea of the purely relative rates in different _ plants, it cannot be depended upon to give results which are at all comparable with their normal absolute transpiration rates. Thus if we arranged the plants according to their normal transpiration— rates, they would stand from highest to lowest thus: daisy, coleus, portulaca, geranium; but if a similar arrangement were made from _ the results of the potometer experiment they would fall into the fol- lowing order: daisy, geranium, portulaca, coleus. It was necessary x therefore to find some other method for measuring transpiration whereby the plant could be kept on its own roots in the soil and inas nearly normal condition as possible. As at least a partial solution of this problem, I would suggest the following method for measuring directly the transpiration of plants on their own roots, a method which provides at the same time for* supplying them with a constant and uniform current of air. The method is based upon the well-known affinity of phosphorus pentoxid for water, whereby the two are combined and phosphoric acid formed. This compound has long been used as a drying agent and as a meals - of separating from air or other gases their water-vapor content, for the purpose of measurement. To this end senha quantities of air are me drawn through U-tubes containing P, 0. oe : Fig. 1 will show the method of setting up the apparatus. The o apparatus consists essentially of a glass cylinder of suitable size to be 3 used as a transpiration chamber, two U-tubes for P,O,, and a aspirator of known capacity. These are connected by rubber tubing, — so that as the water flows from the aspirator a known quantity of ait ait may be drawn through the cylinder and the pentoxid tubes. The 2 cork in the top of the transpiration cylinder has two holes, one for oF the insertion of a thermometer and the other for the connecting tube to the pentoxid series. The cork for the bottom of the cylinder # has two holes; through one is passed a short bent tube serving as an for the outside air; the other is to accommodate the stem of the plant. The cork is cut in halves, so that it may be fitted around the pla before inserting i in the cylinder. If the stem be not large enough - the hole in the cork completely, this may be made. close by pack! 1908] FREEMAN—DETERMINATION OF TRANSPIRATION I2I with vaselined absorbent cotton. The phosphorus pentoxid tubes used were 21°™ long and were fitted with glass stop-cocks and with suitable intake and outlet side tubes. ‘The P,O, was arranged in layers held apart by glass wool, so that the air could pass through it freely. Graduated aspirators fitted with stop-cocks at the base, and rubber stoppers at the top, would of course be more suitable, t Fic. 1 but in the experiments I conducted 19. 5 liter bottles, fitted with two- pied tubber stoppers, for the intake tube and the outflow water Syphon, were used with satisfactory results. Wei begs the U-tubes are filled with P,O,, numbered and carefully up hg aspirator is filled with water and the whole apparatus “ the joint cing taken that. all the connections are properly made an S airtight. The stop-cocks in the U-tubes are turned off, so © nO Moisture may reach the P,O, between the time of weighing and 122 BOTANICAL GAZETTE — [aucust the beginning of the experiment. The last operation is the insertion of the stem of the plant into the cylinder. This should be done as quickly as possible and the exact time noted. The stop-cocks in the U-tubes are then turned so as to allow free passage of air, and the water is started running from the aspirator. As the water flows from the aspirator, a steady current of air is thereby drawn into the transpi- ration cylinder, where it passes over the leaves, out through the outflow tube at the top, thence through the pentoxid tubes, where both the moisture of the normal air and that given off by the plant is absorbed. One tube is usually quite sufficient if it is fresh, but since I used the same tube a number of times without refilling, it was thought best to use a second tube as a guard, and as a means of indicating the exhaus- _ tion of the water-absorbing capacity of the first tube. The flow : of water from the aspirator was so regulated that each experiment lasted approximately an hour. The area of leaf surface, the cubic contents of the transpiration cylinder, and the capacity of the aspirator in the experiments made were approximately in the proportion of 1:5:500. Of course the leaf surface varied considerably in the different experiments, since it was impossible to obtain the same amount each time. It will thus be seen that the air in the transpira tion cylinder was changed 100 times in 60 minutes, or once in every 36 seconds. The rise in humidity in the cylinder due to transpiration of the plant can therefore easily be controlled by regulating the rapidity of the flow of air through the cylinder or by changing the amount of leaf surface inclosed. The exact time when the watel ceases to flow from the aspirator is noted, the stop-cocks in the U-tubes are cut off, and the plant severed from the parent stem at the point where it enters the cylinder. The plant may be kept in the transpira- tion cylinder until ready to be weighed. When the flow of air throug® the cylinder ceases, the contained air soon reaches the saturatio? point and the plant is thus kept fresh until ready for weighing and jor putting the leaves in the press for area determination. The increase in weight in the pentoxid tubes gives the sum of the amounts of water transpired by the plant in the given time, plus the water present in the quantity of air used; therefore it becomes necessary to know the exact water content of the air. This may be found by use of the sling psychrometer, the wet and dry bu 1908] FREEMAN—DETERMINATION OF TRANSPIRATION 123 ‘ thermometer, or by passing a given quantity of the normal air at the time of the experiment over phosphorus pentoxid in U-tubes in the same manner as in the case of the transpiration experiment itself. I prefer the latter method, as it is more direct and accurate, corrections are not required for altitude, barometric pressure, etc., and it calls for little extra labor to set up the additional apparatus and to run it simultaneously with the other. If all of the aspirators be of the same size, it will simply be necessary to subtract the increase in weight of the tubes used for the normal air from the increase in weight of those used in the plant series to find the actual amount of water vapor transpired by the plant in the given time. By dividing this amount by the product of the area of the leaves and the duration of the experiment expressed in minutes, and then multiplying this quotient by 60, the transpiration rate per hour per unit area is obtained. ; The degree of accuracy of this method may be measured by check- Ing it against the transpiration of a cut stem in a potometer or of a plant in a sealed pot. In my experiments I used the cut stem of an alfalfa plant. The leaves were removed from a few inches of the lower part of the stem, which was then inserted in a bottle of water through an opening in the cork which was thoroughly sealed over and around the stem with paraffin. By making several weighings of this plant before and after its use in the transpiration apparatus, its Tate of loss of water was determined for the time before, during, and after its inclosure in the cylinder. The net increase in weight in the P.O, tubes, after the weight of water present in the amount of normal “t used has been subtracted from their total increase, should of course equal the loss in weight of the potometer during its inclosure in the cylinder. This method of checking was repeated three times with Ae ease results, details of which are shown in Tables Il It will be noted from Table II that the last weighing of the potom- aid Was made at 3:10, or two minutes before it was placed in the fs linder, and that the first weighing thereafter was made at 4:18, or ve minutes after the air ceased to pass over the P,O, tubes. The ein of water transpired during these intervals must be subtracted om the total of 0.150 grams as shown in Table II before comparing “with the net gain of the P,O, tubes. Again referring to Table I, it 124 BOTANICAL GAZETTE [AUGUST . TABLE IT POTOMETER WEIGHINGS - Be Loss: os Time mt «(aoe per min.: Remarks oe g Ea e| srams gra 4 PAD P.M ie oes 108 .890 CGE eae erent cw on ; S°IG Pee eee. 108.775 24 0.115 | 0.0048 | The rate in normal air before the experiment : 4:18 P.M.......| 108.625 | 68 ©.150 | 0.0022 | Includes the period — which the plant was inclos PAR POM 108.540 | 30 0.085 | 0.0028 | The rate in normal air after the experiment TABLE III Plant placed in cylinder 3:12 P. mu. Water stopped flowing from aspirator 4:13 P. M. Duration of experiment 61 minutes. Total gain in weight of P.O, tubes 0.343 grams. Amount of water in air used 0.217 grams. Net gain of P.O, tubes 0.126 grams. will be seen that for the first of these intervals the rate was 0.0048 for two minutes or 0.00968"; and for the second, 0.00288 for five minutes or o.o140®, making a total of 0.02368". Now, 0. 1500 — 0.0236 =0.1264; it is thus seen that the two methods check within 0.0048" for a one hour’s run. It would be useless to give the details of the other two check experiments, since they were carried on in exactly the same manner and extended through approximately the same length of time. It will suffice simply to show the results of the three experiments, corrected for time, as follows: TABLE IV Transpiration | Transpiration F as recorded by | as shown by Difference potometer P,O; tubes RES SI Se eRe? Merges Ist experiment............. o.1264gm ©. 12608m o.c004e™ and experiment... . jas. 0.0690 °. ©.0030 ard experiment... 3. ©.0614 0.0624 0.001! 1908] FREEMAN—DETERMINATION OF TRANSPIRATION 125 It will be noted again from Table IT that the transpiration rate was greatly reduced during the time the plant was in the cylinder. This was of course due to the increase in relative humidity in the air, owing to the transpiration from the leaves. It may be suggested, therefore, that the plant was thus shown to be under abnormal conditions. However, the normal air in the room was at a temperature of 27° C. and contained 10.9" water per liter. According to the Smithsonian tables, such air at saturation contains 25.4™8 per liter; the relative humidity of the normal air was therefore 42 .5 percent. Since 19.5 liters of air were drawn through the transpiration cylinder, from which the P,O, collected 343™ of water, the air in the cylinder con- tained 17.5™8 per liter. This would give a relative humidity of 68.8 per cent. The change in relative humidity from the outside air to that inside the cylinder was thus seen to be from 42.5 per cent. to 68.8 per cent. This cannot be termed abnormal, since much greater changes in the outside air take place from day to day, and the range In a given day is very often even wider. Since the air was completely changed in the cylinder every thirty-six seconds, this condition of meidity must have been reached during that time, and have remained “onstant for the remainder of the hour. Owing to changes in tempera- ture and light a plant in the open will vary much more in the transpira- ton rate in the course of a few hours than did the alfalfa plant when Placed inside the cylinder. Until the exact effect of light, humidity, and temperature are known, therefore, and reduced to formulae mieteby, the conditions of the given transpiration experiment being known, the transpiration constant for that plant can be estimated, fe Parative transpiration experiments must be made at the same . under conditions as nearly identical as possible. The to the de = repeuments are moreover valuable only in proportion sree in which identical conditions are approached. one er to test the practicability of this method in the field, I Which tive hapes esas growing within about 12™ of each other, ey had :. marked differences in form and texture of the leaves. therefore of . previously cut at the same time and the stems were to bloom +, or SOU binge OF growth, that is, just asses On these va Ja simultaneous comparative experiments were made © plants, in order to ascertain whether apy constant 126 BOTANICAL GAZETTE [AUGUST difference could be shown to exist in their transpiration rates per sq. cm. of leaf surface. The following table gives the details of this work, The column marked “check”? contains the data derived from the apparatus set up to measure the quantity of water in the normal air. An examination of Table V shows a constantly higher rate for no. 64 over that of no. 67; the rate of difference, however, was very variable. Unfortunately a larger leaf area was taken each time for no. 67, so much so that the relative humidity in its cylinder was higher than that of no. 64 in the first two experiments. This fact would place no. 67 at a disadvantage in these two experiments, since the higher relative humidity would retard to a greater degree its transpiration rate. Had it not been for the third experiment, therefore, in which, notwith- standing the greater leaf area of no. 67, the total transpiration of no. 64 was greater, thereby causing a higher relative humidity within its cylinder, the series would have been inconclusive. This third experiment, however, confirms the results of the other two, by showing that plant no. 64 may even overcome the disadvantage of a higher relative humidity and still transpire nearly twice as much per sq. C™. of leaf surface as the other. It may be well to add here several suggestive details for those who wish to use this method. On account of the strong affinity of P05 for water, it must be kept very tightly sealed. Moreover, it 1s 4 difficult substance to handle, especially to transfer to the mouth of a small U-tube. I have found it very convenient to keep it in such . flask as is made especially for holding anhydrous copper oxid. = has a small neck out of which the P,O, can readily be poured into the test tube, is fitted with a good ground-glass stopper within, a” a ground-glass cap without. I have found that phosphorus pentoxid keeps perfectly dry in this form of bottle; the stopper does not stick fast, and it is ready for use at any time. In filling the U-tubes it is well to push a bit of glass wool into the tube with a glass rod, pour on this about o. 5" of P,O,, then _ wool and more P,O,, until the tube is filled. A bunch of glass ¥0 is put on the top, so that in handling the tubes the P,O, will not get into and clog the intake and outflow tubes while they are being handled, between the times of weighing and setting up the apparatus: 1908] FREEMAN—DETERMINATION OF TRANSPIRATION TABLE V FIRST EXPERIMENT aye [eusa} -Xa jo 91n} -viodura [, Japurysd jo @pIisul 91} -eiodura [, Iie feusa}xa jo Ajtprur “hy aayepy "uD *bs SSIABOT jo BoIe [R10], SIARIT JO Joq -winu [e}0], poesn Ive ul 39} -eM JO "3N pepua qusuttiadx7y ee uve. qusuw oda a tequiaydag aeq Saree nee Plant no. SECOND EXPERIMENT A. M. A.M. THIRD EXPERIMENT 10.9 | 80.4 Oe hiwocr 21.452 33.810 29 II 68 77 84 205 289 127 128. BOTANICAL GAZETTE [aucust It is advisable to have a number of tubes already filled where work is being done in the field, in order that several parallel experiments may be run before returning to the laboratory for making weighings. The same tube may be used repeatedly so long as there is a part of it filled with dry P,O,. Care should be taken, however, to set up the tube in the same way each time, that is, to have the air enter and pass out of the tube in the same direction. The reason for this is that the phosphoric acid, after being formed from P,O, plus water, will itself take up water. If now the tube be turned so that perfectly dry air in leaving the tube passes over the phosphoric acid, which has previously taken up an excess of water, it will itself take up water from the acid and the tube will lose weight. It requires some experience to know how much leaf area to include in the cylinder for each experiment. After a few trials, however, one will learn to estimate sufficiently closely the capacity of the apparatus so as not to overcrowd it. Overfilling is indicated by the collection of moisture drops on the side of the cylinder, show- ing that the air inside has reached the saturation point. This may be remedied either by reducing the amount of leaf surface inclosed, or by increasing the rate of flow of the water through the aspirator. This method of measuring transpiration may be said to be only 2 t d adaptation of the methods used by L RE’ and E. and J. VeRSCHAFFELT,? in that air is drawn over the plant the same manner, and the transpired moisture collected in U-tubes containing hygroscopic substances which are not contained in the vessel with the plant, but are connected in the same aspirating series, so that the air, after passing through the evaporation cylinder, next passes through the U-tubes. However, a different absorbent is used and the apparatus, moreover, is adapted for measuring transpiration of plants on their own roots. The essential point difference, nevertheless, lies in the condition of the air as supplied 1 « GANEAU DE LAMARLIERE, L., Recherches physiologiques sur les feut les, deve loppées & l’ombre et au soleil. VI. Transpiration. Rev. Gén. Botanique 43579 1892. ; the ? VERSCHAFFELT, E. en J., De transpiratie der planten in koolzuurorije ange Botanisch Jaarboek (uitgegeven door het kruidkundig genootschap “Dodonaea Gent) 2:305. 1890. 1908] FREEMAN—DETERMINATION OF TRANSPIRATION 129 the plant. While in my method normal air is supplied, both of the above investigators first completely dried the air before allowing it to reach the plant. This is detrimental, for as BURGERSTEIN® says: “In Gegensatze zur zweiten hat die dritte Methode, bei welcher die evaporierte Wassermenge aus der Gewichtszunahme hygroskop- ische Substanzen in Erfahrung gebracht wird, den Nachteil das sich die Pflanze in einer zu trockenen Luft befindet.” SUMMARY 1. In plant breeding and in physiological and ecological work, it is very necessary to have some accurate and practical method of measuring the transpiration of plants. 2. The potometer method does not give the normal transpiration rate of a plant, neither can it be depended upon to give a rate which 's even comparative as between different plants. 3- By the method herein described the transpiration of a plant under known and constant conditions may be accurately measured. 4. It is possible by this method to demonstrate individual differ- €nces in the transpiration rates in different plants of the same species. 5: By the use of this apparatus, data may be secured to serve as a basis for plant selection and breeding. MANHATTAN, Kansas 3 ; ery BURGERSTEIN, ALFRED, Die Transpiration der Pflanzen 12. 1004. THE TOXIC PROPERTY OF BOG WATER AND BOG SOIL ALFRED DACHNOWSKI (WITH SIX FIGURES) The publication of recent work on the existence of injurious sub- stances excreted from roots of plants (19, 12, 16,) has necessarily resulted in disclosing to ecologists some overlooked data. Repeatedly it has been shown that the commonly accepted environmental factors are not always sufficient to explain certain important problems of association among plants. It must be admitted, therefore, that there is a problem to be solved not only regarding the relation of one field crop to another, but also with reference to the succession of one plant society by another. In the study of the structural adaptations of bog plants and the causes of their occurrence in bog areas, various theories have been brought forward. The idea generally current among workers in the ecology of bogs is that the geographical distribution of bogs and the local differences in the flora of bog areas and swamps have probably come about chiefly through post-glacial migrations and changes in the physiography of the habitat. The cause determining the structural characteristics of bog plants is generally understood to lie in the “physiological dryness” of the habitat. But while some writers lay stress upon low temperature of the bog substratum and the presence of drying winds as the prominent factors (11, 7, 8), others emphasize humous acids in the soil, abundance of soluble salts, and (15). More recently the effect has been correlated with low tempera ture and lack of aeration of the subsoil rather than with acidity (6, 17). In 1904, while at work on the ecology of ravines near Ann Arbor, Mich., the writer became convinced that the reactions of plants e their habitat were equally as great and profound, in some cas if the influence of edaphic and climatic factors. In various pce decomposed remains of an earlier vegetation led to mechanical chemical changes in the soil, the extent of which was more € ffective Botanical Gazette, vol. 46] [9 1908] DACHNOWSKI—TOXIC PROPERTY OF BOGS 131 toward breaking up the flora into a heterogeneous formation, accom- panied by a frequent replacement of one dominant group by another (3). These reactions of plants seemed still more pronounced in bog societies. During the past year a grant obtained from the Emerson McMillin Research Fund afforded an opportunity to test by physi- ological methods the nature of plant reactions. The investigation here reported forms a part of a more extended study on the ecology of Buckeye Lake. This brief report is merely intended to reveal the toxic character of bog water and bog soil. A more detailed account, together with data obtained from an inquiry on the possible isolation and identification of the toxic bodies by a method of fractional dis- tillation, will appear later. uckeye Lake is situated 40*™ east of Columbus, Ohio, in a region free from limestone. It is an extensive body of water about 16*™ long and 1.6*™ wide, and was formerly known as the Licking reservoir. The reservoir was originally a lake in the glacial drift. Its chief supply today is the south branch of the Licking River. In 1883 and again in 1834’ its water surface was raised by forming a dike around: the west end. Near the northern bank, and midway between the small towns of Lakeside and Avon- dale, is a bog island, approximately one-tenth the dimensions of the lake. Soundings which were made to determine the character of the peat gave Q-12™ as the depth of the island. With its surface Yegetation of distinctly northern forms, the island is virtually a water vulture on a large scale. The plants are not dependent for any " Pottant part of their food on the soil; rooting in the soil at such “pth is not possible here. The vegetation presents two well- marked zones: a central one consisting of sphagnum, several eee of Carex, Menyanthes trifoliata, Dulichium arundinaceum, : heu chzeria palustris, Eriophorum, Oxyzoccus, Drosera, Rhus ee Aronia nigra, and others; and a marginal zone which nic y besides various forms of Salix, Alnus incana, A. rugosa, Ilex a. ata, Cornus canadensis, etc., a few small oaks, and Acer Ach as the dominant form. Mycorhiza is quite common 1 a “Sie Many plants are strictly hydrophilous, and such ea tivated variety as are grown in either zone for experiment Purposes show marked difficulties of absorption, soon become stunted, 132 BOTANICAL GAZETTE [AUGUST and often take on xerophilous characters. In the following account these zones are spoken of as the central zone and the mafle-alder zone respectively. The bog water and bog soil used in the experiments were brought every month to the laboratory in glazed earthen-ware jugs from stations which remained identical throughout the period of investigation. To ascertain the osmotic pressure of the bog water, determinations of the freezing-point were made. As compared with the freezing- point of pure distilled water the average lowering in the various deter- minations is 0°007 and 0°0og for the central station and the maple- alder station respectively. Compared with similar determinations for Michigan bogs (13) the bog water of Buckeye Lake has no higher concentration. Data on temperature deviations in the bog substratum are omitted here as having no particular significance in the problem at hand in this region. They do not seem adequate to account for the differences, since plants growing in soil, nutrient solutions, or bog water are equally affected. If there is any property of bog water which prevents rapid and successful invasion of plants, this inhibiting influence must rest not in the physical character of the habitat alone, but in some chem!- cal quality as well. A study of the acidity of the bog water under examination gave results differing but little from those obtained in the Michigan bogs (13). Titrations were made with a n/1oo KOH solution. The bog water from both zones is alkaline to methyl orange and acid to phenolphthalein. A comparison of the acidity figures shows that the bog water of the central station is uniformly less acid than that of the maple-alder zone. Boiling, however, greatly reduces the acidity ° the bog water in the latter station. This is due to the escape of car- bonic acid. In the light of the results here brought out, the presence of the toxic bodies is not necessarily to be correlated with high acidity : To determine the presence and possible nature of the injurious substances affecting plants through their toxic effects, the following experiments were planned. Familiarity with the behavior and the conditions of development of Marchantia polymorpha (4) suggest marchantia gemmae of known history as an indicator for preliminary observations. A large number of gemmae were placed in cryst 1908] ' DACHNOWSKI—TOXIC PROPERTY OF BOGS 133 dishes (9.5% 4°™) containing 100°¢ of bog water. Cultures were prepared, containing respectively the untreated bog water from each zone and spring water. The gemmae were allowed to float on the surface of the solutions. An additional series of test conditions was arranged at the same time from the bog water of each zone variously treated. In the table given below, culture medium no. 3 is bog water aerated daily by means of a rubber bulb; no. 4 is prepared by mixing with the bog water dry calcium carbonate and then filtering off the solution; no. 5 is treated by shaking the bog water with carbon (lampblack) and then filtering off the solution; no. 6 is a culture medium obtained by growing in distilled water in battery jars a set of representative plants from each zone. The attempt is made here to simulate undrained bog conditions and to test the water for excretions of roots. To discover whether the effects of poisons were also mani- fest in the bog substratum, a relatively concentrated aqueous extract Was prepared. Quantities of the subsoil from each station were — from a ‘layer 30°" below the surface vegetation and dried Mm an Oven at a temperature varying between 52° and 60° C. One gram of the material was then mixed with 100° of distilled water ane left standing for several days. The soil solution thus obtained as used as culture medium no. 1. There were thus produced six conditions for each zone in which it was possible to test the bog soils, te excretions of bog plants, the effect of aeration, and toxic ingredients : eee Water, The following Table I shows the results of growth length of marchantia gemmae during a period of twelve and twenty- five days. bs : hep be noticed that the gemmae made scarcely any growth in the eae while in the untreated bog water a fairly good wee Evidence P inhibiting action of these solutions is plainly marked. the first me pe _ further obtained from a microscopic study. ssi ten days es . six days the sete made some growth, but - tWo opposi 63 ps spe ceased. Only in the untreated bog water the e Posite growing points of the gemmae were thrifty in appearance. the iat er to narrow threadlike filaments, which > solutions sete day began to broaden at the tip. In Were hd 5 th Was greatly increased after treatment. Exceptions nly when the bog water used was collected just following 134 BOTANICAL GAZETTE [AUGUST TABLE I MARCHANTIA POLYMORPHA Growth in 12 Growth in 25 days days Remarks Culture solution y Length in mm. | Length in mm. I. Central zone: 2 hy SoC SO extracts an. .ss- Sign dese = fe. cas dead after 8 days 2. Bog water untreated..... sted are Ls5- 2 filamentous outgrowths 3. Bog w. erated i2.%, ‘ 4 toes! 4. Bog water neutral....... ae Dears as 5. Bog water filtered....... 7.5-8 Liss 6. Bog plant water......... 2 5 7. Spring Water csc sces 5.6 3° 4 feet II. Maple-alder zone: 1. Bog soil extract..)...... I I -.2 larger number dead after 2. Bog water untreated..... 0. =935 II 3. Bog water aerated....... 8 i 12 4. Bog water neutral. 6 16. 5-14 5. Bog water filtered....... 5. +8 IO---EI 6. Bog plant water......... 5 -6 Io -I2 a period of heavy rains, or when the vessels containing the bog water were left uncorked. The differences in growth in the various solutions were less marked, showing that the degree of toxicity at one concen- tration was entirely different at another. The same is to be said of solution no. 6; its toxic character became more marked with increase in the time during which the bog plants were under cultivation. Briefly summarized, the data thus far agree in showing (x) that the contrasts in the relative growth of plants in solutions from the maple-alder zone were less marked than those in the solutions from the central zone; (2) that the inhibiting factors of bog conditions are in part due to the presence of injurious water-soluble substances; (3) that the central zone possesses these toxic bodies more decidedly than the maple-alder zone; and (4) that in both zones the toxicity can be corrected by a method of aeration and by the use of calcium carbonate and carbon black. | | A series of experiments was next made in the form of bog water cultures with various cultivated plants. Half-liter glass jars of the Mason pattern were used, and prepared in the conventional way- The seeds were germinated in sawdust. Germination in qU Fi sand and in paraffin-coated disks of galvanized iron wire was pee less satisfactory. Transplanting was done when the plants 1908] DACHNOWSKI—TOXIC PROPERTY OF BOGS 135 attained a height of 5-6°™. The culture media used were prepared as indicated for marchantia. From two to six plants were used for 4oo°* of solution. Each experiment was continued for 7 to 10 days according to the amount of water transpired before renewing the Fic. 1—Whea Numbers 4s in the text, p. x t plants from various cultures of bog water and bog soil. 33- Six plants from each solution. culture Solution. The different cultures always stood side by side > the university greenhouse, so as to give uniform environment. The light conditions were the same also; direct sunlight was avoided by cloth Screens. In place of temperature and moisture readings, Measurements of the evaporation power of the air were obtained from 136 BOTANICAL GAZETTE [AUGUST the records of two atmometers. The instruments were prepared on a scale as given by LIvincsTon (14). The integration of humidity, temperature, and air-current data given in a weekly rate varied be- tween 200 and 270°. Fic. 2.—Wheat plants from various cultures of bog water and bog soil. Numbers as in the text, p. 133. Six plants from each solution. : As an aid for comparing the rate of growth of similar plants ™ different media various criteria were used. The main emphas!s, however, is placed upon the total transpiration for a definite period of growth, since the difference between the amounts of water lost me been shown to be equivalent to the difference between the physiolog! 1908] DACH NOWSKI—TOXIC PROPERTY OF BOGS 137 value of the solutions (19). Other criteria employed were the con- dition of the roots, green and dry weight of plants, length and anatomical structure of roots, stem, and leaves. None of these alone can be regarded as accurate measures of plant activity, but taken together they generally agree in indicating the relative value of the results. Without dwelling here at length upon the exact data derived from these experiments, only the results in transpiration-increase are given below intabularform. The percentage increase in transpiration is calculated for the larger number of the plants upon the basis of the quantities for the bog soil solution considering it as unity. TABLE II PERCENTAGE INCREASE IN TRANSPIRATION o a as i o rh 32 Culture soluti 3 g i 2 | 38 E 3 § 3 : on Ss é Z2 8 ra a 3 6 a é I. Central zone: 1. Bog soil extract*.... . . ° fe) ° ms ; 2, water untreated. 19 | 16] 113 | 22} 68 A es 3. Bog water aerated... 5 27 | 201 ee ais 8. 4. Bog water neutral. ... 209 gI Too ee oe 5 Bog water filtered 245 52 | 225 | 215 94 /38.8 47 oF og Wher fo: 8 ace II. Maple-alder zon 7 pa oe 1. Bog soil extract*,... ° fo) ; 2. Bog water untreated. 38 | 65 | 287 = 3- Bog water aerated... 164 Bog water neutral... 298 | 136 | 335 i $ Bog water filtered... __ 256 76 - Bog plant water....... I 40 | 178 ed gm % *4°™ of bog soil and 400° distilled water. An increase in the dry weight of roots and tops was obtained in all plants growing in the solutions treated with CaCO, and carbon black. For the corn and wheat respectively the increase in the 7 Matter produced varied from 20 per cent. to 50 per cent. during the time of the experiment. It will be observed that the evidence derived from wheat, corn, bean, elm, and buckeye seedlings (two years old), and other plants yields results and conclusions similar to those pointed out for mar- ‘hantia. The plants grown in the bog soil extract and in the untreated veal show stunting clearly in the roots. The tops of the plants ore nearly alike, except in the stronger solutions. Marke 138 BOTANICAL GAZETTE [AUGUST differences in the degree of sensitiveness to toxicity or of the oxidiz- ing power of roots are noticeable for the various plants. Phaseolus and Vicia jaba proved thus far to be the most plastic plants. In the solutions filtered with CaCO, and carbon black the tops surpass in Fic, 3.—Corn plants from the various cultures of bog water and bog soil Numbers as in the text, p. 133. Four plants from each solution. development the growth of roots. The plants show marked vari tions in the internal structure of leaf and stem. Those grown the bog soil extracts show distinct xerophilous characters. The leaves are reduced in area, thicker, of a deeper green, and with revolute 1908] DACHNOWSKI—TOXIC PROPERTY OF BOGS 139 margins; responses which cannot be attributed to light but to a reduced transpiration current (18) consequent upon the toxicity of the habitat (figs. 1-6). It is worthy of note in this connection that when grown in a 0.01 Ee oe Se plants from the various cultures of bog water and bog soil. 5 as In the text, p. 133. Four plants from each solution. Per cent. solution of strychnin sulfate, atropin sulfate, or other xe body of a similar nature and with a high reducing power, the —e dwarfing effects are obtained with-Phaseolus. When treated with CaCO, and carbon black the solutions become highly beneficial. The accelerated growth and transpiration are no doubt due to the 140 BOTANICAL GAZETTE [AUGUST presence of these substances in small amounts, and the behavior of the plants is very much like those grown in a 0.ooo1 per cent. solution of strychnin or atropin sulfate. The striking agreement of results obtained from such a variety of material seems sufficient proof that the factors inhibiting plant growth and plant association and succession are at least in part due to the plants themselves. Carbon black and calcium carbonate add no soluble matter to the solutions (2), hence it becomes certain Fic. 5.—Average plants of Phaseolus multiflorus, showing effect of bog water variously treated. Numbers as in the text, p. 133. that the beneficial effects cannot be due to the introduction of nutrient material but to the taking up, i. e., the adsorption of injurious substances present. This would indicate, therefore, that the chang® in the soil conditions are produced by noxious substances formed 10 the absence of O,. They may be products of decomposition, per haps they are in part plant excreta, but whatever their nature, they are water-soluble toxic bodies which retard oxidation in the tiss¥® and decrease transpiration, thus causing xerophily, stunting, and even death, It may be readily questioned whether part of the response from a deficiency of oxygen in the soil. The evidence obtain arises ed by 1908] DACHNOWSKI—TOXIC PROPERTY OF BOGS I41 BENNETT (I) is against aerotropism in roots. It follows, therefore, that results reported as due to lack of aeration in the bog sub- stratum are really due to toxicity. Under natural conditions the inhibiting effect is eliminated by aeration, a slow process of oxida- tion preventing the accumulation of injurious plant excreta in the te jaba from cultures of the central zone. Numbers as in text, p. 133: a and photograph by Miss FREDA DETMERS. However, on account of the great demand for oxygen, the sie a be carried on efficiently only near the surface. Beneath, active bodies are more plentiful in the dead material than in the oe. An undrained peat substratum, i. sass adi i. aimee more marked deterioration in development and per association and succession of plants than a drained habitat. soil, 142 BOTANICAL GAZETTE [aucusr That the response to toxic bodies when present in small amounts ~ may lead to acceleration of growth has become evident also in con- nection with a biometric study on the annual wood-increment in Acer rubrum (5). Measurements upon such trees from the outermost edge of the maple-alder zone as were nearly the same in size, age, concentric growth of wood, and general environment, as similar forms found in woodlots near the shore gave the following differences in the frequencies of rings: Width of rings in mm........ . af X | 4.5} 2 >| 2.8) 313-5 4 ae Frequencies in bog-habitat.......| 16 | 10 | 23 | 20 | 27 | 12 | 20| 5| 7] 5 Frequencies in woodlots ......... 20402) 35 19 Width of rings in mm............ 6|.6.5| 7 | 7.5} 8 | 8.5] 9 | 9-5) 2 Frequencies in bog-habitat........ s|-s | 6| 2} 24 Of eee Frequencies in woodlots.......... The mode and the variation constants derived from them are equally interesting: PIB UGE: oe tbat Seas rae are Bog Woodlots MOGs Seis ois eS et ee eee 3mm 2mm Meanin Si hors ee ee 3.425+0.098 1. 701+0.038 Standard deviation oo 1.870+0.069 0, 566+0.027 Coefficient of Variability... 4 - 35 ae 54.60+ 2.55 33-284 2-46 ee We have here the type and the place-habit from two distinct edaphic conditions. The differences in the soil habitat have led to physiological variations which changed not only the type, but the variability and even the sign of the skewness. Quantity and quality of the wood have been affected; as products of the environment they are a measure of environmental conditions. To attempt to correlate the data with the work of previou on toxic action is obviously impossible. Definite knowledge of thé chemistry of bog water and bog soils is lacking at present. There are always present a great variety of chemical and biological agents, and products of decomposition, which may react collectively. Henc¢ definite conclusions cannot be based upon the results obtained aii The limited extent to which these experiments have been carried, giv no more than a suggestion of the possibilities. s authors Onto STATE UNIVERSITY olumbus 1908] DACHNOWSKI—TOXIC PROPERTY OF BOGS 143 _ LITERATURE CITED I. Bennett, M. E., Are roots aerotropic? Bort. GAZETTE 37:241. 1904. 2. BREZEALE, J. F., Effect of certain solids upon the growth of seedlings in water cultures. Bor. GAZETTE 41:54. 1906. 3- Dacunowsk1, A., Contribution to the es survey of the Huron River valley. Mich. Acad. Sci. Report 9:116. c. , Zur Kenntnis der Entwicklunge- Physiologie von Marchantia poly- morpha, Jahrb. Wiss. Bot. 44: 251-286. 1907. ——, Type and variability in the annual wood-increment of Acer rubrum. Ohio Naturalist 8: 7343. 1908. » Fria, J., and ScHROTER, C., Die Moore der Schweiz mit Beriicksichtigung der gesammten Moorfrage. Geol. Komm. d. Schweiz. naturf. Gesells. Bern. 1904. 7. Ganone, W. F., Raised peat bogs in New Brunswick. Bot. GAZETTE 16:123. 1897. ra uw Can. I. :13r. 9. JENSEN, G. i= oe as limits and stimulation effects of some salts and poisons on wheat. Bot. Gazette 43714. * ——, Some mutual effects of tree roots and grasses upon soils. Science N.S. 25:871. 1907, - Krarman, A. O. , Pflanzenbiologische Studien aus russisch Lappland. Act. Soc, Pe os Fenn. 6:113. 1890. 12. Livincston, B. E, , Studies on the properties of an unproductive soil. U. S. Dept. of Agr., Soran of Soils, Bull. 28. 1905. ‘+ Physiological properties of bog-water. Bot. GAZETTE 39:348. Igo5. , Raised Sy bogs in the province of New Brunswick. Proc. Roy. Soc. 897. * — The relation of desert plants to soil moisture and to evaporation. : arnegie Institution of Washington, Publication 50: 1906. 5: Scrmrer, A. F. “; ee auf chealsoen be Grundlage. Gustay Fischer, og 18 INER, O., and ate H. S., The production of deleterious excretions 17 “Si ‘8 Bull. Torr. Bot. Club 34279. 1907. : SEAU, E. N., The bogs and the bog flora of the Huron River ee: Bor. GAzeTTE Ge: 8. 1906. » The development of palisade tissue and resinous deposits in leaves. Scene N. S. 19:866. SOE a EY, M. and Cameron, F. K., The chemistry of the soil as related to vg production. U.S. Dept. Agr., ‘Bae of Soils, Bull. 23. 1903- 16. BREEFER ARTICLES THE FLOWERS OF WASHINGTONIA (WITH FIVE FIGURES) While my paper on the genus Washingtonia! was passing through the press, I had the pleasure of receiving from Dr. BEeccari a copy of his recent monograph of the Coryphine palms of America.? In his treatment of Washingtonia this distinguished palmographer gives much weight " certain floral characters which have been heretofore overlooked, and It seems desirable that these should be brought to the attention of American botanists, in order that their value may be tested by field studies. hese distinctions relate to the characters of the filaments, the stigma, and the summit of the ovary. In the flowers of Washingtonia the filaments of the stamens opposite the lobes of the petals are consolidated with them ; for nearly oe ee ye lengils mae : than the free pee op- posite the sinuses. Washingtonia ee Wendl. is defined having the lobal mee he thickened - fusiform; t . 3-lobed, u top; the stigma undivided (‘‘puntiform® sempre ?”’). Fig. 1 represents this species, es Fic. 1.—W. filijera Wendl., Botanical Garden, Palermo, August, 1906.— O. BECCARI. X3.5 and decidedly smaller seeds. is drawn from flowers of a tree growing in Botanical Garden at Palermo, Italy. Its variety microsperma Beccari d slightly less strongly fusiform lobal but mostly in its somewhat small ae Fig. 2 shows the variety, drawn from flo iffers in its filaments; er flower of a tree in the Garden Ricasoli, Port Ercole, Tuscany. Bor. Genie bas ieee figs. 12. Dec. 1907. I take this oppo two errors: Page 409, line 18, = Mueoae read “‘fifteen;” page 415, li bottom, for “the trees” read “most of the trees.” 2 Bec , Opoarpo, Le Palme Americane della tribé Corypheae- dalla Webbia : 2: 2pp- 343- Oct. 1907. Firenze Botanical Gazette, vol. 46] Estratto 1908] BRIEFER ARTICLES 145 The rank of species and variety seems here assigned somewhat arbi- trarily, and it may be of interest to give the history of the trees which have been taken as their respective types. The palm accepted as typical W. juijera is a certain tree in the Garabaldi Garden, at Palermo, Italy, which was raised from seed at the Botanical Garden in the same city, in 1874, and which began to flower in 1892. The source of the seed is not known. Five or six living plants of the Prichardia filifera of his trade catalogue were exhibited by LinpEN at the international exhibition at Florence, in May, 1873. Three of these exhibition plants . are now large trees, pro- ducing flowers and fruit, and these are taken by Brccart as the types of his W. filifera micro- Sperma. As these palms are directly traced to Linpen, and were exhibited by him as Pri- chardia filifera, it would seem probable that they are about as near as we are likely to get to authentic representatives of WENDLAND’S first published species. : The flowers of W. robusta Wendl. are Fic. 2—W. filijera ee described as having the lobal filaments tuber- = parca pt culately enlarged at the coherent base, and eee. dl 3.5- abruptly subulate above; stigma bilabiately : sParted into three short lobes; ovary turbinate at summit, but neither *xcavated nor gibbous. On these grounds Beccarr sustains the specific Tank of this palm; and should they prove constant, it may be desirable '0 follow this disposition. Fig. 3 is from a flower of a tree in the Botanical Garden at Palermo. Its historical identification with the Wendlandian plants is not related. The first two characters hold in the flowers of Californian trees which have been referred here, so far = Concerns the few specimens I have examined. The ovarian character '8 less Satisfactory. W. gracilis Parish has flowers very near those of the last, except that the “mmit of the turbinate ovary is very distinctly 3-lobulate. Fig. 4 was tes from a flower taken from Mr. McLeon’s tree, a panicle of oo 1S 4 Sec of fig. ro of my previous paper. Brccari regards this palm as anety of W. robusta. It would be possible, although in my opinion 146 BOTANICAL GAZETTE [AUGUST undesirable, to regard all the Washingtonias as varieties of a single poly- morphous species, but the one now under consideration would of all be the least capable of such comprehension. Without question floral characters Fic. 3.—W. robusta Wendl., Botanical Garden, Palermo, August, 1906.—0. BECCARI. X3.5. are of greater diagnostic value than those drawn from foliage or habit; but when the latter are of marked distinction, and apparently constant, they cannot be refused great weight. \ ; ese VAS ‘ Fic. 4.—W. gracilis Parish, Riverside, Cal. X5- Beccart had not had an opportunity of examining flower of ul sonorae S. Watson, and he regards it as a doubtful species, which as a variety of W. robusta, suspecting that the obtusely triangular insert) 1908] BRIEFER ARTICLES 147 the petiole in the leaf blade may not prove a constant character. Through the kindness of Dr. B. L. Rosryson, of the Gray Herbarium, I have received a few flowers taken from the type specimen of this species, collected by Wrti1aM PatMER at Guaymas, Mexico. One of these is represented in jig. 5, the anthers being omitted, as all had fallen from the flowers. It will be seen that this has the characters assigned to W. filifera so far as the filaments are concerned, the character of W. robusta as to the divided tip of the stigma, and the markedly lobate ovary of W. gracilis. Such a com- bination of characters throws a shadow of uncertainty on their value. It Fic. §.—W. sonorae S. Watson. From PALMER’s type, Guaymas, Mexico. X5. must be remembered, however, that they are drawn from a study of too few individuals. What is now desirable is that the proposed characters, both those drawn from the flower and fruit, and from the foliage and habit, should be put to the test by the examination of numerous examples, growing under varying conditions. Especially is it to be hoped that botanists who may have the opportunity should study carefully the groves near Guaymas, and those reported to exist on the seacoast of northern Lower California. Until such extended studies shall be made it cannot be considered that we Stand on altogether firm ground in the discrimination of the various indicated Species and varieties of Washingtonia. , For the drawings from which jigs. I, 2, and 3 are reproduced I am indebted to the kindness of Dr. Brccart. They are enlarged seven —— Figs. 4 and 5 are from drawings by Mrs. CHARLOTTE M. TLDER, and are enlarged ten diameters. All the drawings are reduced one-half in the reproduction.—S. B. PartsH, San Bernardino, California. CURRENT LITERATURE BOOK REVIEWS The question of sex The determination and inheritance of sex have presented problems of peculiar interest and also of peculiar difficulty. CorRENS' has grappled with them from a new point of view and has gained some surprising results. His point of attack is through the hybridization of plants having different sex characteristics, a8 — for example the crossing of a dioecious species with a hermaphrodite or monoe- cious species. His most important conclusions are that each germ cell of the forms he has used carries a progamic sex tendency, but that the actual deter- mination of sex is syngamic, that is, it results from the chance that brings together two germ cells having particular sex tendencies. In Bryonia dioica he shows that the female germ cells carry always the same sex tendency, namely to produce females; while the male germ cells are of two kinds, half bearing the female tendency and half the male. The male tendency dominates over the female, = that when the eggs are fertilized by these two kinds of sperms, those which receive sperms bearing the female tendency produce females, and those which are fertil- ized by sperms bearing the male tendency produce males. ‘The females ar homozygous (2+) with respect to sex and the males are heterozygous (o+8): Evidence is presented that the same condition exists in Melandrium album, 2 shown by crossing with Silene viscosa, and he considers it very probable that all dioecious plants are similarly constituted. The author is properly cautious discussing the applicability of these results to other classes of organisms thant with which he has dealt, and especially to animals, but he discusses Watson noteworthy studies upon the idiochromosomes of the Hemiptera,” and points Ha how readily these can be interpreted on the basis of’a sex relation similar t thai discovered in higher plants. epigamic modification of sex through the influence of nutrition oF Ks external conditions is not deemed to be wholly excluded, owing to the fact that iia sex may carry the other in a recessive or latent condition, and it is at least com ceivable that such latency may be to some extent modifiable by external ee In respect to the sex of hermaphrodite and monoecious plants, it is noted ted in all cases of “mosaic” inheritance which have been sufficiently invests Correns, C., Die Bestimmung und Vererbung des Geschlechtes nach 55508 Versuchen mit héheren Pflanzen. pp. 81. figs. 9. 1907. Berlin: Gebriider — 2 Witson, E. B., Studies on chromosomes. III. The sexual differences of cod chromosome groups in Hemiptera, with some considerations on the dete: tion inheritance of sex. Jour. Exp. Zool. 3:1. 1906. 148 1908] CURRENT LITERATURE 149 there is a distinct factor present for the mosaic condition, so that the sex of such plants is not to be looked upon as due to the presence of the male- and female- producing units alone, but to the presence of a factor determining the tendency to be hermaphrodite or monoecious respectively. The field for investigation which has thus been thrown open is a very inviting one, and it is to be hoped that other dioecious species which have nearly related hermaphrodite or monoecious species among both plants and animals will be made to yield whatever support they may for the generalizations CorRrENS has made.—GrorceE H. SHULL. Plankton of Illinois River Four years ago, this journal reviewed the first part (1903) of Korom’s Plankton of the Illinois River, which dealt with the quantitative investigations and general results. There has just appeared the second part, which deals with the organisms of the plankton and their seasonal distribution. The character of the work, with its mass of statistics, forbids an adequate review. As was stated in the preceding review, this series forms the most important contribution yet the most painstaking care. In the discussion of species, plants occupy 45 pages, and animals 230. The plant groups considered are Bacteriaceae, Schizophyceae, Chlorophyceae, Bacillariaceae, Conjugatae, and certain s plants. Some general conclusions in reference to the seasonal changes are stated, conclusions that are promised detailed discussion in a later paper. For example, each month 1s characterized by certain plankton features, dependent upon a certain range of hydrographic, thermal, and chemical conditions, and of illumination. There 'S @ certain range of component species, and a range of numbers of individuals, the Proportions varying from month to month, and constituting one of the main elements in the seasonal changes of the plankton. Transitions from month to month are most profound at seasons of greatest environmental changes, as at the times of vernal increase and autumnal decline in temperatures. In general two types of plankton were found, the summer and the winter, the vernal and autumnal types being only transitions between the two when organisms from both are present. The winter plankton is characterized by a small number of species peculiar to that Season, and a number of perennial forms; the summer by a larger number of summer organisms with the perennial forms. In reference to the question whether the plankton of streams differs from that Of lakes and ponds, the author states that it may be distinguished from them - being a mixed plankton (due to the mingling of planktons from all sources in the § Bor. Gazerre 372472. 1904. *Korot, C. A., The plankton of the Illinois River, 1894-1899, with introduc- to oc MpOn the hydrography of the Illinois River and its basin. Part II. Con- Papa organisms and their seasonal distribution. Bull. Ill. State Lab. Nat. Hist. * 1c le I. pp. vii+ 360. 1908. 150 BOTANICAL GAZETTE [AUGUST . drainage basin), in being subject to extreme fluctuations in quantity and consti- i C. ‘ tution, and in containing no species peculiar to it—J. M. Floral mechanism Such is the title of a work whose first part has just appeared.’ In this part twelve types of common spring flowers are selected, all of which are readily cultivated and may thus be kept under continued observation. In the case of each one of these flowers there is a full account of all the details of structure and the problems presented. A definite scheme of work is elaborated, so that in due order all questions are raised and answered. The work is intended for botanical students, teachers of elementary botany, “lovers of flowers,” and candidates for examination. A single example, selected at random, will illustrate the scheme. Under Viola odorata the following topics are presented: history, distribution, nomen- clature, description, variations, floral diagram, sectional elevation, developmen special mechanism, pollination, cleistogamy, monstrosities, fruit and seed, com- parison of allied types, theoretical considerations, and note on Fibonacci phyllotaxis systems. All this is illustrated by five plates, three of them colored. The large page and handsome type are exceedingly attractive, and the colored plates are as fine as we have seen. In short, the whole appearance of the book is ornate. But still, we wonder at its purpose. The author explains this as fol- ows: “The general idea has been the provision of a methodical framework for the inclusion of all facts of observation and experiment, which may serve as a? introductory scheme admitting of progressive elaboration and perfection with the attainment of new information.” is sounds as if there was a pedagogica motive; but if it is for the teaching of botany, the tremendous emphasis laid upo? a few “type” flowers is something new or something very old; at least it holds no relation to botany as at present developed. If it is a scientific treatise, which the author disclaims, it is too simple and diffuse. If it is for ornament, it is a great success. If it is to give opportunity for the display of admirable printing and three-color work, we have seen nothing better.—J. M. C. MINOR NOTICES j Kew Index.—The third supplement to this invaluable work has appeere including names and synonyms of all genera and species from the beginning 4 gor to the end of 1905. The second supplement, which appeared in 194 re included names through 1900, was under the direction of W. T. ELTO: 5’ CHURCH, ARTHUR Harry, Types of floral mechanism; a selection and descriptions of common flowers, arranged as an introduction to the syst study of angiosperms. I. Types I-XII (Jan. to April). Royal 4to. pp- ¥? with 39 colored plates and numerous figs. Oxford: Clarendon Press. 1908. $6. Supplementum tertium. PP: itl 6 Index K is pl Oxford: Clarendon Press. 1907. 28s. 1908] CURRENT LITERATURE I5I Dyer. The third supplement appears under the direction of D. PRrary, the new director of the Kew Gardens. e supplement is a record of the remarkable activity in taxonomy during the five years covered, and critical judgment in reference to this great volume of work is becoming increasingly difficult. In fact, the list is a record of publication rather than an expression of opinion. For example, 476 acknowledged species of Crataegus are recorded for the five years, and Rubus is not far behind. To review such a work is impossible. It is only necessary to announce its appearance.—J. M. North American Flora.—The third part of volume 22 has just been issued. It contains Grossulariaceae by F. V. Covirte and N. L. Brirron, 43 species (2 new) being referred to Ribes and 4o (4 new) to Grossularia; Platanaceae (6 spp.) y H. A. Grrason; Crossosomataceae (4 spp., 1 new) by J. H. Smarz; Connar- aceae (3 genera, g spp.) by N. L. Brrrron; Calycanthaceae (4 spp.) by C. L. Porrer; and the beginning of Rosaceae by P. A. RYDBERG, the key recognizing 18 tribes, 6 of which are completed and the seventh (Potentilleae) begun. Among the 19 genera of Rosaceae presented, Horkeliella (3 spp.) is new; and 29 new species are described, being distributed among Opulaster (4), Spiraea (5), Petro- phytum, Aruncus (3), Chamaebatiaria, Lindleyella, Vauquelinia, Sericotheca (6), Horkelia (6), and Ivesia.—J. M. C. Marine algae of Sweden.—KvurN’ has published a monograph of the algal flora of the west coast of Sweden. The species of the four following groups are first presented: Chlorophyceae (12 fams., 26 gen., 71 spp.), Fucoideae (16 fams., 5? geN., 105 spp.), Bangiales (5 gen., 11 spp.), Florideae (16 fams., 55 gen., 107 spp.). One new genus (Acrothrix) of Fucoideae is described. The second part of the contribution (80 pp.) presents the ecological factors and analyses the Seographical distribution. At the conclusion of the discussion, the 105 species of Fucoideae and the 118 species of Florideae (incl. Bangiales) are distributed Into arctic, subarctic, boreal-arctic, cold-boreal, and warm-boreal groups. The Paper concludes with “biological” notes, a full bibliography, and an adequate index.—J. M. C. Das Pflanzenreich.’—Part 33 contains the g genera of Aloineae (Liliaceae) by A. BercEr, Chortolirion being a new genus with 4 species. Altogether, 370 Species are presented, many of them with numerous cultivated forms and entering Into hybrids. The large genera are Aloe (178 spp., 14 new), Kniphofia (67 spp., ? new), Haworthia (60 spp.), and Gasteria (43 spp.). : __ Part 34 contains the Sarraceniaceae by J. M. MACFARLANE, who gives an interesting account (in English) of the structure of the vegetative organs and the Sie ‘Kyu, Haratp, Studien iiber die Algenflora der schwedischen Westkiiste. PP- 288. pis. 7, Upsala. 1907. (Inaugural dissertation. , s ENGLER, A., Das Pflanzenreich. Heft 33, Liliaceae-Asphodeloideae-Aloineae yon ERGER. pp. 347. figs. 141 (817). Mz17.60. Heft 34, Sarraceniaceae von ARLANE. pp. 39. figs. 10 (43). Mz2.40. Leipzig: Wilhemn Engelmann. 1908. 152 BOTANICAL GAZETTE [AUGUST insect relations of this remarkable family. Heliamphora and Darlingtonia are still recognized as monotypic, but a new species of Sarracenia (S. Sledgei, from the Gulf states) is described, 7 in all being recognized.—J. Lactarius and Russula.—BatraiL_E® has published a monograph of these genera, to which he gives the group name Astérosporés, on account of their echinu- late or granulate spores. He describes all of the European species, adding personal observations to the diagnoses of the various authors. The keys are admirably constructed to lead easily to the species. For Lactarius the author has adopted the classification of QuéLET. For Russula the two grand divisions (Leucosporae and Xanthosporae) of QuUELET are continued, but a number of subsections are defined and named. At the same time, it is shown, that the color of the spores is not a very reliable character, and the principal groups must be defined by a varying combination of characters.—J. M. C. Grout’s Mosses.—The fourth part of this work,'® issued in April last, main- tains the reputation of its predecessors and brings the author’s task within sight of completion. Part V, the final one, is announced for 1909, to contain some plates and text missing from this part, together with an index and other useful adjuncts. Part IV completes the Leskeaceae and contains a good part of the Hypnaceae, with the usual excellent reproductions of illustrations from the Bryologia Europaea and SuLLivant’s Icones, and some characteristic details which are original.— C. Rik Index of desmids.—A supplement to NorpstEepr’s Index Desmidiacearum, which was published in 1896, has just appeared.*' The interval of over ten years has witnessed such an accumulation of material that a large supplement became necessary. The new bibliography included bears testimony to the great activity of the students of the group during this period, about 500 titles being enumerated, under 120 authors. To examine this vast amount of material and to organize it for the purpose of the index has called for an amount of labor that the students of desmids are sure to appreciate.—J. M Flora of Greece.—The last fascicle of Haldcsy’s Conspectus Florae — was published in 1904, and now a supplement has been issued.1? The first 1as- t 9 BATAILLE, FREDERIC, Flore monographique des Astérosporées (Lactaires ¢ Russules). pp. 100. Besancon (route de Vesoul, 18): The author. 1908. /7-3- te Grout, A. J., Mosses with hand lens and microsco pe. A non-technical 2 book of the more common mosses of the northeastern United States. Part Road, 8vo. pp. = 318. i hide figs. 134-165. Brooklyn: The Author, 360 Lenox Flatbush. $1. th cela cS “ O., Index Desmidiacearum citationibus locupletissimus atque bibtinndioias. Stpplestntin. pp. 150. Berlin: Gebriider Borntraeger. 1908. "? HarAcsy, E. DE, Conspectus Florae Graecae. Supplementum. pP- Leipzig: Wilhelia Engelmann. 132+ 1908] CURRENT LITERATURE ‘ 153 cicle appeared in 1900, so that four to eight years have elapsed since the various parts appeared. During this period the author says that local and visiting botanists have been extremely active in exploration, discovering new stations, plants new to Greece, and new: species. All these additions have been brought together in this supplement, so that the Conspectus may be regarded as fairly complete again.—J. M. C. Anatomy of dicotyledons.—The translation of the SOLEREDER’s Systematische Anatomie der Dicotyledonen'3 into English gave the author opportunity to revise the work and to add much supplementary matter. This has now been brought together at the instance of the German publisher for the benefit of those who have the original. This large Erganzungsband will be desirable for all those libraries that have the first two volumes, for it contains an immense amount of material. Besides the additional data, the concluding remarks have necessarily been revised. mae Se ae CB NOTES FOR STUDENTS Sieve tubes in Laminariales.—Miss SyKEs"™ has investigated the anatomy and histology of Macrocystis and Laminaria, chiefly M. pyrifera and L. saccharina. A few other species, such as Sacchariza bu osa, Laminaria digitata, Alaria escu- lenta, and N ereocystis Luetkeana, were also examined to supplement the main tesults. Chief attention was paid to the morphological nature of the trumpet hyphae and of the true sieve tubes, the presence or absence of protoplasmic con- necting threads, the development of sieve plates, and the nature of callus. Some of the conclusions may be summarized as follows: (1) The trumpet hyphae in M. pyrifera and L. saccharina are to be looked upon as true sieve tubes. They represent the original central cells of the thallus modified, and may be termed primary pith filaments. Though they differ as to their degree of development, they are certainly homologous with the secondary sieve tubes of Macrocystis, paper ete similarly derived from the modified primary cortex of the young thallus. (2) It is believed that the histology of the sieve plates in the primary pith fila- ments and secondary sieve tubes is essentially the same. Threads are formed ee nn the young sieve plates, and each gives rise in the older plate, apparently ¥ means of ferment action, to a slime string inclosed in a rod of callus. In __toeystis each original thread first divides to form a group, and each thread of * group forms its own callus rod, but finally, by fusion, only one slime string is ei | from each group. The older sieve plates are obliterated by the depos ait, @ 'arge mass of callus over their surface, and callus is also formed through- € length of the old sieve tubes. (3) The callus is to be looked upon as a I ere *3 SOLE fir Labora Imp. 8vo REDER, H., Systematische Anatomie der Dicotyledonen. Ein Handbuch orien der wissenschaftlichen und angewandten Botanik. Erganzungsband. i * PP. vili+422. Stuttgart: Ferdinand Enke. 1908 vs —_c » M. G., Anatomy and histology of Macrocystis pyrifera and Laminaria - Annals of Botany 22: 291-325. pls. 19-21. 1908. 154 BOTANICAL GAZETTE [AUGUST hydrated form of cellulose, and is found in L. saccharina and L. digitata in various states of hydration. It appears to be produced in the young sieve plates by the action of a ferment on the already formed cell wall, but is afterward accumulated by deposition from the protoplasm, both on the surface of the sieve plate and on the lateral walls of the tube. (4) The histology of the sieve tubes agrees with that of spermatophytes. The only contrast between the method of obliteration of the sieve tubes in Laminariaceae and Pinus is that in the latter the heads of the slime strings are still visible on the free edge of the callus cushions, and the path of the slime strings can be traced throughout the callus mass; while in Macro- cystis and Laminaria the callus is laid down by the protoplasm of the sieve tubes over the heads of the slime strings, so that they are buried by the overlying callus and no perforations can be traced through the rod. (5) The protoplasmic connecting threads throughout the tissue of M. pyrifera and L. saccharina wete demonstrated, but it is impossible to be certain of their formation in case ° secondary attachment.—S. Y AMANOUCHI. Primitive angiosperms.—Miss SARGENT has developed more fully her view as to the origin of the monocotyledons,'5 which was stated formally in 1993: The present paper of course deals with the characters of primitive angiosperms, but this is a necessary corollary to the recently developed phylogenetic position of monocotyledons. It is an abstract of a course of eight lectures delivered for the London University about a year ago, and even then leaves the discussion of te origin of the flower to the recent paper by ARBERand PARKIN.*® Itis impossible to discuss the numerous lines of evidence presented and the inferences drawn from them. In general it may be said that facts are treated with a free hand and not always critically, that they are often related to one another with great bold- ness, and that the conclusions are in some cases more evident than the proofs. Reasons for believing in the monophyletic origin of angiosperms are presented, and with the recent development of our knowledge of vascular anatomy, it is questionable whether there exists today any serious objection to this view And yet, perhaps it is well to have the situation summarized for us. he reconstruction of the primitive race of angiosperms is based chiefly ied floral structure, stem anatomy, and number of cotyledons. The outcome is @ plant with a strobiloid flower (as Magnolia), with a cambium, and with 1° cotyledons. A comparative study of pteridophytes, gymnosperms, and ne sperms would seem to make the last two conclusions inevitable, and the least partially true. e real contention of the author, however, is the origin of donous condition. There is a very full discussion of all possible the monocotyle- alternative 15 SARGENT, ErHer, The reconst Annals of Botany 22:121~-186. figs. 21. 16 ArBeR, E. A. N., and Park, J., On the origin of angiosperms. _ Soc. Bot. 38:29-80. 1907. See Bot. GAZETTE 443389. 1997- ruction of a race of primitive angios} I a * Linn. 1908] CURRENT LITERATURE 155 and the conclusion reached is that the fusion hypothesis is the most tenable; that is, the two lateral cotyledons of primitive angiosperms have become phylogeneti- cally fused in monocotyledons, and the result appears as a terminal member. The anatomical proofs of this position are fairly well known and seem cogent. The final question asked is as to the cause of fusion, and the answer is, the geophi- lous habit of the primitive monocotyledons. The author recognizes the fact that there are other distinctive features of monocotyledons which geophily cannot be called upon to explain, but these are “(departures from the primitive type.” To boil it all down: the angiosperms are monophyletic; the monocotyledons are derived from the primitive dicotyledonous stock; the terminal “cotyledon” is a historical fusion of two lateral cotyledons, which was induced by geophily; and the other characters of monocotyledons remain to be explained.—J. M. C. Polar conjugation in angiosperms.—Recently'? PoRscH attempted to explain the embryo sac and double fertilization in angiosperms. He holds that the two synergids are homologous with the neck canal cells of the gymnosperm arche- gonium (as to what gymnosperm has two neck canal cells, we are left in doubt); that the oospheres of gymnosperms and angiosperms are homologous; that the Upper polar nucleus is homologous with the ventral canal cell of the gymnosperm archegonium; and that the antipodal end of the angiosperm sac is the equivalent of the micropylar end. The triple fusion results from the essentially female character of the polars. It is with considerable surprise that we find an observer so acute as ScHAFF- NER" writing that the view of Porsc# in regard to these homologies has much in its favor, and that his interpretation of the triple fusion seems correct. That the or gymnosperms and angiosperms are homologous, no one denies; but the other homologies are so inaccurate that to note them at all seems useless. 4n following the reduction of the archegonium, one notes in the bryophytes a shorten- ing of the neck and a diminution in the number of neck canal cells. In the = Filicineae there are two neck canal cells separated by a wall; in the higher Filicineae there is one binucleate neck canal cell, the wall always failing to develop. In the Hydropteridineae even the nuclear division fails to take place and there is only one small, uninucleate neck canal cell; while in the gymnosperms there 1s no neck canal cell at all. In some gymnosperms there is a ventral canal cell, sep- Stated from the egg by a wall; but in more cases there is only a nuclear division without the formation of a wall, and in Torreya even the nuclear division is sup- 5 In the Gnetales we note the disappearance of even the archegonium. ‘iach lling such a series, it is difficult to understand how anyone could propose homologies as those suggested by PorscH.—CHARLES J. CHAMBERLAIN. und ohn Otto, Versuch einer phylogenetischen Erklarung des Embryosackes oppelten Befruchtung der Angiospermen. Jena: Gustav Fischer. 1907- 8 sss : S “\ SCHAFENER, JOHN H., On the origin of polar conjugation in the angios : 10 Naturalist 8: 255-258. 1908. 156 BOTANICAL GAZETTE [AUGUST Gametophytes and embryo of Cunninghamia.—This monotypic Chino- Japanese genus has been investigated by Miyake, who has just published a pre- liminary notice’? of his results. The male gametophyte has no prothallial cells, and at pollination it consists of two nuclei (generative and tube). These two nuclei enter the pollen tube, in which the generative nucleus soon divides, one of the daughter nulcei entering into the structure of the rapidly enlarging body cell, and the stalk nucleus remaining free in the cytoplasm of the tube. Pollination occurs early in April, and the tube reaches the archegonial complex about the end of June. There is a solitary megaspore mother cell, which divides about the time of pollination. The embryo sac is invested by a distinct tapetal zone, and before the end of June is full of tissue. The archegonium initials appear early and the development of archegonia is rapid, the complex being fully formed by the end of June. This complex is singular in that the group of archegonia (15 in the case illustrated) surrounds a central mass of sterile tissue. The cutting-0 of a ventral nucleus and its rapid disorganization were observed, this division being promptly followed by fertilization during the first week of July. The fusion nucleus soon divides, and the two daughter nuclei pass to the base of the eg: Walls appear after eight nuclei are formed, which is apparently true for Pinaceae without exception. The proembryo comprises three tiers of cell, with the usual functions.—J. M. C. continuous to the very base; possess a well-marked centripetal xylem; the vascular bundles there is a complicated double sheath of transfusion a 0 coniferous leaves, which has been described by WoRSDELL as representing etal xylem, JEFFREY regards as a relic of the inner transfusion sheath. way he has connected Pinus with the Cordaitales through Prepinus; ae shown that the Mesozoic pines display transition characters between he and the pines of today. His conclusion is that the Abietineae are the oldest tt of Coniferales, and that Pinus is its oldest living representative —J- M. C. 19 Miyake, Kitcut, The development of gametophytes and embryogeny ics ninghamia (Preliminary note). Bot. Mag. Tokyo 22:45-50. figs. 14- 1908. 20 JEFFREY, EDWARD C., On the structure of the leaf in Cretaceous pines. of Botany 22:207-220. pls. 13, 14. 1908. 1908] CURRENT LITERATURE bay | Aerotropism.—Potowzow has taken up the question of the response of plant organs to gases.2*_ Reserving the usual term aerotropism for sensitiveness to the mixture of gases that compose the air, he proposes the term aeroidotropism for sensitiveness to pure gases. This seems an unnecessary refinement of terms. Very properly he criticizes the use of roots as subjects for experiments with gases, since the organ is under wholly unnatural conditions, and uses stems, which SAMMET tried with negative results. Potowzow finds Brassica Napus, B. Rapa, Vicia sativa, V. Faba, Pisum sativum, Lupinus albus, Phaseolus multiflorus, and Helian- thus annuus sensitive to O, and CO,, but unaffected by Hand N,. The grasses studied were all indifferent. At the beginning there is a positive curvature, which becomes more rapid, slows, ceases; shortly a negative curvature sets in, gradually increasing. When stimulation ceases, curvature slows, stops, and then the recovery of the normal position takes place. The active region may be a centi- meter or more distant from the perceptive region, which may even be in the part of the stem that has ceased growing, showing that perceptive capacity persists longer than capacity for the curvature reaction. The perception time was found to be 0.5 sec. with o.or°¢ of CO, and periods of stimulation and rest in the ratio 1:3. The reaction time was found to be not much more than in various tactic responses; PoLowzow thinks because the movements in both cases were exam- ined by the microscope, and he pleads for the use of the more refined methods of the animal physiologists. There is certainly nothing to prevent; Bosr has blazed the path. We hope that in the full paper to which this is preliminary the the author will give us such records and discuss more fully some general questions Taises.—C. R. B. Seed production in Pinus.—Under this title HayDon”? presents the results of as extended field study supplemented by cytological work. The cytological conditions found in both microsporangiate and megasporangiate cones at various Seasons are noted in detail. The staminate cone, in the vicinity of Liverpool, Passes the winter in the spore mother cell stage. The megaspore mother cell ap- pears about the end of May, but its origin was not determined. Occasionally large ventral canal cells are formed, and in a few cases the first mitosis in the aly observed when there were no traces of pollen tubes or other evidences of robeerang HAyDon believes this supports the suggestion of the reviewer? hic: large ventral canal nucleus might fertilize the egg. The simultaneous ns at the base of the egg by which the proembryo passes from the 8-celled say ee 12-celled stage is sometimes in the lower tier instead of in the upper oe lly the case. Theoretically, the ovulate cone might produce some Pe — W., Experimentelle Untersuchungen iiber die cone UNTER . liufige sa besonderer Beriicksichtigung der Einwirkung von Gasen. ae ng. Ber. Deutsch. Bot. Gesells. 26a: 50-69. 1908. ' a OE apg WaLtTER T., The seed production of Pinus sylvestris. (Inaugura a roc. and Trans. Liverpool Biol. Soc..22:1-32. figs. 16. 1907. OT. Gazetrr. 423349. 1906. 158 BOTANICAL GAZETTE [AUGUST 1500 proembryos, but actually it produces only ro to 20 seeds. The factors respon- sible for the difference between the theoretical and the actual output are consid- ered, both in the field study and in the cytological work.—CHaArLEs J. CHAM BERLAIN. Geotropic curvature.—Poropko, reinvestigating the statement of Koxt that “the geotropic curvature extends also to parts of the stem in which growth can no longer be demonstrated,”’ comes to the contrary conclusion, though he does not discover the source of Kout’s error, unless in the fact that he did not use the microscope in his measurements.?4 Bacu’s conclusion that the presentation and reaction times for geotropic curvatures are not affected by shaking and jarring, has been welcomed by oppo- nents of the statolith theory of geoperception as depriving it of an important sup- port, though Bacu himself does not so use his data. HABERLANDT, whose experiments in shaking and jarring led him to quite the opposite conclusion, reexamines BAcu’s data, criticizes his methods somewhat, and interprets some of his experi t h g the very thing which BAcu thought they did not show.?5 HABERLANDT also pays his compliments to LiNsBAUER, who raised a theoretical objection to the value of the jarring experiments. The statolith theory has a watchful champion, ready to meet all comers.—C. R. B. A lycopod with a seedlike structure.—Miss BENSon’s abstract of her paper on Miadesmia was noticed in this journal.?° The full paper has now appeared,” and the fuller description and plates make the situation more evident. The discovery of the sporophylls of this minute, herbaceous, paleozoic lycopod, has shown a clear relationship to the ligulate Lycopodiaceae, especially Selaginella. The megasporangium produces a single, thin-walled spore, which germinates # situ. An integument is developed around the sporangium, leaving 4 micropyle; and from the surface of the integument numerous long processes develop, giving quite a fringed look to the apparatus. At maturity. the sporophyll is shed, the whole structure resembling a winged and fringed seed. The relation of this “integument” to the “‘velum” of other groups is vague and apparently : worth considering; but another case of integumented sporangium, to be added to the previously described Lepidocarpon, is quite worth while.—J. M. C. . Dwarf male prothallia.—Booprr?® has observed that if Todea phiciel : filmy species, be kept in a sufficiently damp atmosphere, the sporangia do no 24 Poropko, T., Nimmt die ausgewachsene Region des orthotropen Stengels 4” der geotropischen Kriimmung teil? Ber. Deutsch. Bot. Gesells. 26a: 3-14- ‘ ps 25 HABERLANDT, G., Ueber die Einfluss des Schiittelns auf die Perception geotropischen Reizes. Ber. Deutsch. Bot. Gesells. 26a: 22-28. 1908 26 Bot. GAZETTE 44:318. 1907. ic 27 BENSON, MARGARET Miadesmia membranacea Bertrand; a new palaeo ve lycopod with a seed-like structure. Phil. Trans. Roy. Soc. London B. 199:409-4 pls. 33 -37. 1908. aaa Todea- ] rd 1 , ae) eee f Annals of Botany 22:231-243. pl. 16. 1908. 1908] CURRENT LITERATURE - 159 dehisce, and spores germinate in the closed sporangia. As a result, dwarf male prothallia are produced, antheridia sometimes appearing at the three- or four- celled stage. Free spores under the same conditions never produce such pro- thallia, not having developed sexual organs at the conclusion of the experiment. The dwarf males do not burst through the wall of the sporangium, and ultimately die. It was found also that both free spores and those inclosed in sporangia ger- minate in.darkness. The suggested explanation of the formation of the dwarf male prothallia under the conditions described has no foundation in experimental work. It is to be hoped that the day of imaginary “explanations” is about over —J..M.C, Periodicity of algae—Brown?? has studied the appearance and disap- pearance of algae in selected ponds and streams in the vicinity of Bloomington, Indiana. In this region, an alga growing under ‘“‘steady normal conditions” remains in a healthy vegetative state throughout the year. A sudden change in external conditions checks this vegetative growth, and induces a resting stage or sexual reproduction. In reference to specific plants, Spirogyra nitida is the most abundant of the Conjugatae in the region studied, and S. varians is the most widely distributed alga, conjugating at all seasons of the year when exposed to har conditions (as the drying-up of a pond); Chaetophora thrives best in slightly Stagnant water at a temperature between 5° and 25° C.; Draparnaldia finds its La congenial conditions in flowing surface water between 1° and 15° C.— -M.C. Cytology of Synchytrium.—Griccs*° has continued an investigation on 5: decipiens begun by F. L. Srevens, to whom he is indebted for material. There até 500 to 860 free nuclei in the cyst when cell walls begin to appear; but most of the Study was upon cysts with 100 to 300 free nuclei. While no centrosomes ws found in the metaphase and anaphase, in the telophase there are large asters with centrosomes at the center, whose origin has not yet been determined. As the nuclear vacuole forms about the chromosomes, the coarse rays of the aster bend about it and become transformed into the thick nuclear membrane characteristic of the senus. It is hoped that a further study will throw some light upon Systematic relations —CHARLES J. CHAMBERLAIN. Spo rangia of Lycopodiaceae.—As a result of her study of the apotang Ore "ing organs of the Lycopodiaceae, Miss Sykes" has arranged the different Ps tg of Lycopodium in a continuous series based on the shape and Te Wee the position of the sporangium, and the age a . eee See € evidence adduced seems scarcely sufficient to —e Harry B., Algal periodicity in certain ponds and streams. Bull. Torr - Club 35: 223-248, 1908 Be aan Bos ium. Ohio Naturalist 8:277- 286. pl. 20. 1908, T. F., On the cytology of Synchytrium. i | : SYKEs, M. G., Notes on th + ngium-bearing organs of the Lyco “) ph ] of t Pp rang wPotliaceae. New Phytol. 7: 41-60. pls. 2, 3. 1908. 160 BOTANICAL GAZETTE [avcusr clusion that the genus Lycopodium should be interpreted as a reduction series, ; or to afford a basis for the supposition that the sporangium-bearing organ of the Lycopodiaceae has been ‘derived from a branch structure which had the mor- phological value of an axillary bud.’”-—Atma G. SToKEy. Aue ; j Embryo and endosperm of Potamogeton.—Cook:? has investigated mati of P. lucens obtained from Cuba. The embryo was found to resemble closely that of Alisma in its development. In endosperm formation a transverse wall chambers the sac at the first division; in the micropylar chamber the endosperm formation proceeds as a series of free nuclear divisions, usually with parietal placing; the antipodal chamber develops as a haustorial extension of the sac into the chalaza, and during this development the second daughter nucleus of the primary endosperm nucleus seems to be very active, but does not divide —J. M.C. Ophioglossum simplex.—This rare Sumatran species has been collected again, and these new specimens show to BowER3 an outgrowth which, evidently single, represents a sterile blade, of which there was no such indication in the specimen he had examined previously. The fact is important because of the difference of opinion as to the phylogenetic position of Ophioglossum. CAMP BELL has regarded O. simplex as the most primitive known member of the genus, while Bower has claimed it to be a reduction form. The evidence just reported would seem to justify the latter contention.—J. M. C. Anthocyan and chlorophyll.—An interesting bit on the function of anthocyan 2 s the observation by Morr that the red leaves of a species uniformly contait “8 chlorophyll than the green leaves. The ratio runs between 1.08 and 1.27- This seems to be difficult to reconcile with TiscHLER’s hypothesis that anthocyal enables the plant to nourish itself better and so to stand a more severe climate. sahil stein cl Adicts er calae Radioactivity.—Acqua reports’ that salts of uranium and thorium, even in very dilute solutions, injure seedlings of wheat by reducing the development the primary root. Germination was also retarded. His experiments supplem®®” those on radium and other radioactive substances by other investigators. —C. oe A 32 CooK, MELVILLE THURSTON, The development of the embryo sac and ember of Potamogeton lucens. Bull. Torr. Bot. Club 35:209-218. pls. 9, 10- 1908. a 33 Bower, F. O., Note on Oppiegiosromt simplex Ridley. Annals of Botany ‘ 327, 328. aie | , T., Ueber den spent ota, eee anthocyanfiihrender Blatter ve “ laufige Mineitungy Bot. Notiser 1908: 49-53. 1908. 35 Acqua, C., Sull’azione o sali radioattivi ie uranio e di torio nella veges Annali di Botanica 6:387-4 “7 | Vol. XLVI hess THE BoTANICAL GAZETTE September 1908 Editors: JOHN M. COULTER and CHARLES R. BARNES CONTENTS The Staminate Cone and Male Gametophyte of Podocarpus L. Lancelot Burlingame Sisyrinchium : Anatomical Studies of North American Species Theo. Holm A New Respiration Calorimeter George J. Pierce The Seedling of Ceratozamia Helen A. Dorety Briefer Articles The Number and Size of the Stomata Sophia H. Eckerson The Absorptive Po ver of a Cultivated Soil : Joseph Rosen and Charles Heller Current Literature i The University of Chicago Press CHICAGO and NEW YORK William Wesley and Son, London The Botanical Gazette A Montbly Journal Embracing all Departments of Botanical Science Edited by JoHN M. CouLTER and CHARLES R. BARNE ES, with the en wr of other members of the botanical staff of the University of Chic Issued September 22, 1908 Vol. XLVI CONTENTS FOR SEPTEMBER 1908 No. 3 THE ei CONE AND MALE GAMETOPHYTE OF PODOCARPUS. Conrri- g FROM THE HULL BOTANICAL LABORATORY I14 Sai TH NINE FIGURES AND PLATES VIII AND IX), ZL. Lancelot Burlingame - , 16! SISYRINCHIUM: ANATOMICAL STUDIES OF NORTH AMERICAN SPECIES (vin j TES X, XI, XIA). Zheo. Holm A NEW RESPIRATION CALORIMETER. George J. Pierce - - - - - - - 193 Rae SEEDLING OF CERATOZAMIA. CoNnTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY I15 (WITH TWO FIGURES AND PLATES XII- xvi). Helen A. Dorety : BRIEFER ARTICLES THE NUMBER AND SIZE OF THE STOMATA. Sophia H. Eckerson - 3 - 221 THE ABSORPTIVE POWER OF A CULTIVATED SOIL ppc THREE FLOURES). Joseph Rosen and Charles Heller a BOOK REVIEWS EEE Ghia 6 ROE ee Oe BIOLOGIC TYPES. A TEXT- BOOK OF BOTANY AND PHARMACOGNOSY, NOTES FOR STUDENTS - ecko : Ae t pee nion, 84 cents on annual ripe ag: (total $7.84), on single copies 11 cents (total 86 cents). q Remittances should nage ade payable he University of Chicago Press, and should be in Chicago or oreo Eo mtbe, postal or express aaa order. 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Be menications for the editors should be —— to them at the University of Chicago, Chicago, Ill. butors are requested to write scientific an d proper names with particular care, to use the metric eights and measures, and in citations to follow the form shown in the pages of the BOTANICAL Pm ‘nd 8 in rilling to pa the ost of the additin excess of thi irty-two A guage pages ida os sa cange! unless the author is willing to pay nal oars in which case the nu ages in the volume is correspondingly incre o| ay ations are f a ee d without nie to author as when suitable originals ares supplied. A copy on Sgestions made he January number, 1907, will be sent on Agee: ication. It is advisable to €r with the editors as - illustrations jequired in any faster to be o attic! ratte rang may be ordered in advance of publication. ‘we -five separates of original Is pans rithout covers will be s supplied gratis. A table showing approximate cot of = separates j Printed on an order blank which accompanies the proof; a copy wi Frill be sent on reques Entered August 21, 1895, at the Post-Office at Chicago, as second-class matter, under Act of a March 3, 1879. VOLUME XLVI NUMBER 3 BOTANICAL (GAZETTE SEPTEMBER 1908 THE STAMINATE CONE AND MALE GAMETOPHYTE OF PODOCARPUS CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY II4 L. LANCELOT BURLINGAME (WITH NINE FIGURES AND PLATES VIII AND IX) Knowledge of the gametophytes of the Podocarpineae is at the present time limited to that contained in three brief papers. In 1902 COKER (3) published an account of two species of Podocarpus; in June 1907 JEFFREY and CHRYSLER (5) added some new facts concerning Podocarpus and Dacrydium; and in September of the Same year Miss Youne (14) gave an excellent résumé of the sub- ject of the male gametophyte and added several new and interest- esting details for Dacrydium. CoKeEr records that in Podocarpus cortacea there are produced two primary prothallial cells, both of which may divide amitot ically; a tube nucleus; and a primary sperma- togenous cell, which gives rise to a stalk cell and a body cell. The body cell undergoes nuclear division and one of the nuclei is then ©xtruded from the cytoplasm, leaving a single functional male cell. JEFFREY and CHRYSLER add to this the interesting details that from © the two primary prothallial cells there may arise by subsequent division as Many as eight prothallial cells. Of still greater interest 1s the record of the “proliferation” of the primary spermatogenous cell, whereby there arise three cells placed transversely, the middle one of which is considerably larger than either of the others. Miss YounG Teports that in Dacrydium one or both of the primary prothallial cells may divide once. From the primary spermatogenous cell arise two Cells, one of which is usually sterile, the other of which functions as the body cell. The interesting observation is made that there is a 161 162 BOTANICAL GAZETTE [SEPTEMBER tendency for both derivatives of the primary spermatogenous cell to function as body cells. The material for the present study was secured through the kind- ness of Dr. L. Cockayne of Christchurch, New Zealand, and Miss INEz FRANCES STEBBINS of the Huguenot College at Wellington, Cape Colony, South Africa. To both are due our thanks for their kindness in obtaining the material at no inconsiderable personal inconvenience. Though the collections were necessarily few, yet they include a considerable range of developmental stages in each of the species. The material was fixed in a 5 per cent. solution of commercial formalin in 70 per cent. alcohol. The fixation has proved unexpectedly good, except for stages from the rounding-up of the mother cells to the time when the microspores have a good firm wall and abundant contents. The shrinkage and general distortion within the limits just mentioned have rendered necessary the omission of a number of what appear to be rather interesting and perhaps impor tant details. Some of these will be mentioned briefly in the general account. It is hoped that other material so killed and fixed as to show details of cytological structure will be in hand within the neat future. The preparations have been imbedded in 54° parafim, Es 3-5 #, and stained in Haidenhain’s iron alum hematoxylin stall, alone or counterstained with various aqueous stains such as orange G, Bismarck brown, erythrosin, etc., and with the saffranin gential- violet combination. Three species have been examined, though not covering exactly the same ground. vate Observations The cones of P: totarra Hallii are of a generally oval — varying from 3 or 4 to 15 or 20™™ in length, and from 2 to 4” 8 diameter. They are usually in pairs, one being large and one a The base of the cones is surrounded by several closely appress* rigid, scalelike bracts. The peduncle is quite short or 4 lacking. The cones of P. nivalis are somewhat shorter, not Paz’™s and decidedly slenderer. The cones of the third species (the a of which was lost in transit) are similar in shape to the first = are smaller. In other respects the cones are very similar. all totarra is one of the tallest of forest trees and P. nivalis a very S™ 1908] BURLINGAME—PODOCARPUS 163 shrub, sometimes creeping. The third species may be P. elongata, a common forest tree of the South African region. This is a mere inference from its abundance in the region from which this material Group of P. dacrydioides in remnant of taxad forest, N. Z.—Photo- Crossy SmitH Fic, A. Staph by 1: 164 BOTANICAL GAZETTE [SEPTEMBER was received, and from the fact that I have received other material from the same source belonging to this species.’ In cross-section a staminate cone shows about ten to twelve sporo- phylls, each with two sporangial cavities (fig. 1). The vascular system seems to be rather weakly developed, but shows a distinct endarch collateral bundle (fig. 3) corresponding to each sporophyll. Just outside of the bundle there usually is found a resin canal (fig. 1). Canterbury Fic. B.—Buttressed base of P. dacrydioides, in ancient forest of Plain, N. Z.—Photograph by L. CocKAYNE. The resin canals contain little material of any sort in the prepa available for study. The distinctly glandular cells lining them (fig. 2) suggest, however, that they are functional. The number varies in different strobili, but in those examined did not fall below six nor exceed eighteen or twenty. The sporophylls as seen from the upper surface are spatulate, with a rather pointed apex. Fig. 4 presents gn out dacry ) somewhat jine : of ’ Ve have received from Dr. CocKAYNE two excellent poe : dioides, which are reproduced on account of their general interest (figs 1908] BURLINGAME—PODOCARPUS 165 of a longitudinal section somewhat to one side of the middle, and will give an idea of the side view, as well as the relation of the sporan- gial cavity to the sterile portion of the leaf. Fig. 6 shows a cross- section of a sporophyll near the middle of the sporangium. The sporangia are somewhat less prominently exposed on the under side than those of Pinus, for example. A single weakly defined vascular bundle (fig. 6) traverses the upper part of the central sterile septum and is sometimes accompanied by a resin canal lying below it and between the sporangia. The wall of the sporangium varies in thick- hess somewhat, but in general on the freely exposed part it is about four or five cells thick (fig. 5). One or two.of the. inner layers are slightly differentiated as a tapetum. This is not very evident and does not occur until the sporogenous tissue has nearly reached the mother cell stage. The tapetum does not long persist, but disap- pears as a functional tissue about the time the young spores have formed a thick wall and wings. All of the wall proper, except the outermost layer of thickened cells, may break down before the spores are shed, The earliest stages of the sporogenous tissue observed (in P. sp.) lacked one or two divisions of the mother cell stage. Fig. 7 will serve _ as a typical Tepresentative cell of the sporogenous tissue at this stage. The walls are thin and delicate, as is usually the case, and the cyto- plasm stains somewhat more densely than that of the wall cells. It Was possible to secure very good preparations of this, considering the nature of the killing and fixing agent. The cells were slightly Strunken, so as to have pulled away in many places from one another or from their own walls. F ig. 7 will show the principal facts. The ‘ytoplasm does not seem to present either a typically reticulated or - Structure, but rather resembles a sort of flocculent precip- pes scattered more or less irregularly through the cell. These floc- an masses May assume a sort of feathery, filamentous, sieniista ee agape form, or they may appear as scattered masses of irregu- ‘iia The filaments and other masses do not seem to be con- b iM any definite manner, but to be distributed through the cell Y chance, No stored food can be detected microscopically in the Yioplasm at this time, though the parenchymatous cells of the axial Portion of the strobilus contain considerable quantities of large 166 BOTANICAL GAZETTE [SEPTEMBER starch grains. The wall cells of the sporangium do not at this time, as in some sporangia (Ophioglossum, for example), contain starch, but are relatively poor in cytoplasm and cytoplasmic inclusions. There is relatively little change in the cytoplasm of the sporogenous tissue as growth advances, except that it grows gradually less dense until at the time of the formation of the young spores there is almost no stainable substance left. The nuclei of the sporogenous cells (fig. 7) previous to the mother cell stage show a structure that is very like that of the cytoplasm just described, except that it is denser and there is more of a tendency to aggregate itself into disconnected masses. There are one OF more large nucleoli present in the nucleus at this stage, as there seem to be in the resting nuclei of all the stages of all the tissues examined. As the nucleus approaches division, the nuclear substance begins gradually to arrange itself into filaments or strands (fig. 8) which may end freely or anastomose with other filaments or masses. About the same time the hitherto nearly uniformly staining material begins to stain differentially, so that filaments seem to link together knots © more deeply staining material. Whether this indicates a difference of substance, as some think, or merely a difference in the state of aggregation, as has been recently maintained by several authors, cannot be said with certainty. However, the gradual derivation of this structure from the preceding one, in which everything seems homogeneous, would certainly point to the latter interpretation as the correct one. During this time the nucleolus (or nucleoli) gr adually loses its density, as shown by the staining reactions. It continues ' do so until it finally does not stain at all or has disappeared entirely: Fig. 9 shows a surface view of a nucleus in which the filaments have become more regular and somewhat thicker. In fig. 10 is esate . spirem, into which the filamentous stage gradually passes, 2 W the deeply staining knots on the spirem are unusually promin : The figure shows nearly all of the spirem that was included 2 3-# section; therefore it probably contains one-third to one-h of the entire spirem, since the nucleus is about 7X10 -- In ae cases the spirem consists of darkly stained masses connected by we smaller threads, and in others, as shown in fig. 10, by broader st 1908] BURLINGAME—PODOCARPUS 167 which seem to be of different material because of the considerable difference in depth of staining. The spirem gradually becomes denser and ramifies all through the nucleus (fig. rz), the nucleolus disappears, and finally the spirem breaks into elongated loops, which arrange themselves into a tangled mass at the equatorial plate. The exact method of division was not made out owing to the close tangling of the long chromosomes. In the anaphase the chromosomes appear as twenty-four straight elongated rods of about half the length of those entering the mitosis g. 12). As the chromosomes approach the poles, the polar ends draw together and the others spread out, so that the daughter nucleus usually has a concavity on the polar side. The chromosomes gradu- ally lose their density and put out processes on one side or the other to fuse with those put out by neighboring ones, thus establishingja sort of reticulate structure (fig. 13). This gradually passes back into the Stage shown in jig. 7. In the reorganizing nucleus one large nucleolus may appear or several small ones, but I did not attempt to discover the origin of them or their relation to one another. When the cells have reached the mother cell stage, they break loose from one another and round up in the usual manner. As already remarked, the mother cells killed and fixed very poorly, so that only * very meager and perhaps uncertain account of them can be given. About the time the mother cells round up many of them begin to abort; this abortion seemingly may occur as late as the young spores. Up to this time and on to the time of the divisions in the young micro- Spores the development of the sporogenous tissue seems to be nearly simultaneous, _ After the mother cells have rounded up, the nucleus soon passes into a condition in which its contents stain so nearly uniformly that it has not proved possible to disentangle its separate constituents. If Stained deeply, it appears absolutely uniform, and if the stain be then slowly and gradually drawn, the homogeneous appearance gives Way to a sort of pebbled one. Sometimes it looks as if this might be due to the parts of a large and long spirem being crowded closely together. This interpretation is strengthened by the fact that in some “ases one can see what looks like the end of a loop pushing out the 168 BOTANICAL GAZETTE [SEPTEMBER nuclear membrane. In other cases the appearance is more that of a great many lumps of some plastic substance thrown into a tight mass. Whether these appearances are normal or not I cannot say. That they represent the only appearances that the present material shows is certain. In the face of the numerous and fairly uniform accounts of sporogenesis in which no such phenomena have been recorded, it is certainly entirely proper at present to ascribe these unusual phe- nomena to the effects of the reagents. Nothing any more nearly resembling synapsis was seen. It should be noted that of some hundred strobili cut only five showed cells in this stage. However, three of these strobili are the only ones that have shown the reduction divisions. A few sporangia had cells like those shown in fig. 14, where the chromosomes are beginning to appear, being almost com- pletely concealed in a mass of granular matter. In the figure the difference in intensity of stain between the chromosomes and the imbedding substance has been greatly exaggerated for the sake of clearness. One gets two views of these developing chromosomes, one in which the chromosomes are mostly seen in cross-section and one in which they lie lengthwise. In some fashion (which the density and abundance of the imbedding substance prevent being made out clearly) out of this comes a rather sharply pointed spindle at whose equator are arranged the short apparently bivalent chromosomes (fig. 15). Some preparations seemed to favor the idea that these apparently bivalent chromosomes then split longitudinally. After passing to the poles (fig. 16) they became surrounded by a nuclear membrane, but did not, in the few preparations of this stage observed, lose their identity in a resting nucleus. A very few cases of the homotypic mitosis are shown in the preparations and all of these are in the telophase, as shown in fig. 17. Walls are not formed till alter second division. Beyond the telophase of the second division the preparations show nothing until after the formation of the wall around the young spoTes- These are so badly shrunken and distorted that no attempt has been made to figure them. It is observable, however, that the nucleus 1S at first rather small and oval and lies to one side of the spore cavity, most of which is occupied by an enormous vacuole. Fig. 18 shows a microspore after the contents have become more abundant. At this 1908] BURLINGAME—PODOCARPUS 169 time starch may or may not be present; later it becomes abundant and occurs in relatively large grains (figs. 30, 31). The wall has a thick exine much roughened on the outer surface and a distinct intine. The spore coat is usually much thinner on the side away from the point where the prothallial cells will later lie. The external appearance of the pollen grain bears a considerable resemblance to~ that of Pinus, except that it is smaller, rarely reaching more than 35 # in the greatest diameter (exclusive of the wings). The microspore nucleus is large (fig. 18) and contains apparently two sorts of material. There is a more deeply staining substance distributed in irregular masses through a very fine ground substance. As the nucleus prepares for division, the amount and density of the more deeply staining substance increases in amount, assumes a more definitely reticulated structure, and finally passes into a rather thick and comparatively short spirem (fig. 29). This spirem breaks up into the chromosomes (fig. 28), which often still show the distinct segmentation into lighter and darker segments that has already been referred to in discussing the sporogenous tissue. This segmentation 1s not always found in the chromosomes or even in the spirem. It might be supposed that the different appearance is due to differ- ences in the depth of stain, but this does not seem to.be true. The chromosomes are rather long and considerably twisted at the Metaphase, but in dividing and passing to the poles they apparently shorten up (fig. 31). What has been said of the first division applies equally well to the next, so far as the few mitoses observed show. One or two prothallial cells are cut off and then the antheridial Initial divides to produce the tube nucleus and the primary spermato- senous cell (fig. 32). In P. nivalis two primary prothallial cells, which do not subsequently divide, seem to be the rule, though one €xample of the division of the first prothallial was observed. The pollen in the same sporangium varies in the stage of development from microspores to the stage shown in fig. 32. These sporangia Were, in some cases at least, shedding their spores. In P. totarra Hallii one primary prothallial cell may be cut off, alter hich the free nucleus divides to form the primary spermatogenous Cell and the tube nucleus (fig. 21); or two primary prothallial cells may be cut off before the tube nucleus is separated from the primary 170 BOTANICAL GAZETTE [SEPTEMBER spermatogenous cell (jigs. 20, 22). When only a single primary prothallial cell is cut off, it may (fig. 19) or may not (fig. 21) divide again. Far more frequently it does divide anticlinally. No case in either species has been observed where either prothallial cell divides periclinally. In case two prothallial cells are cut off, both usually divide anticlinally (figs. 23, 26, 27), although the division may be long delayed or fail wholly (text fig. 4). The first one may remain undivided, or in rare cases may divide twice, so that the first tier of prothallial Ic. 1. Transverse section of a male gametophyte consisting of one pro F cell (p:), the primary spermatogenous cell (ps), and the tube nucleus ().—Fis. cells contains four cells. The second one almost always divides once and usually twice. Thus there may be one, three, four, six, OF eight prothallial cells; six is much the commonest number, and one or eight the rarest. In case only one prothallial cell is cut off, its nucleus 1908] BURLINGAME—PODOCARPUS I7I remains large and the cell itself is often much larger than when two are cut off (ext jig. 1). Sometimes the three resulting nuclei then lie in a row across the spore (text fig. 1) and differ but little from one another in appearance. The walls separating them then run nearly straight across, and it is only by courtesy that the tube nucleus can be said to be free in the spore cytoplasm. To all intents and purposes it is as much walled-off into a cell of its own as the pro- thallial nucleus, for both eventually are freed in a common cytoplasm (text fig. 2). Further, it is to be noted that in this case the prothallial cell does not have a fixed position with respect to the wings, as in the ordinary course of events. After the tube nucleus has been cut off, the primary sperma- togenous cell divides transversely, giving rise to two cells (jig. 25). sually these cells differ markedly in size, the smaller lying to one side and the larger lying nearly in the center of the pollen grain (fig. 26). In this case one may safely use the usual terms for them and speak of the larger as the body cell and the smaller as the stalk cell. It not infrequently happens that the two derivatives of the generative cell are about equal in size (figs. 24, 27; text figs. 5, 6), though even then one is centrally placed and the other laterally. Before the division of the generative cell, the second primary prothallial cell has usually divided at least once. In this case the generative cell often sinks down among its derivatives (figs. 23,27). The stalk cell is some- times placed transversely to the body cell (text figs. 5, 6). Whether these large stalk cells will produce male cells or not can only be con- jectured, though the fact that some of them seem to retain their ‘ytoplasmic envelope, almost as distinct from the cytoplasm as the body cell itself, up to a certain early stage, would lead one to sa ort that in some cases they might do so, Text fig. 7 may show three deriv- atives of the generative cell and two prothallial cells in addition to the tube nucleus. One of the three derivatives of the generative cell has no cytoplasmic sheath and is probably a stalk nucleus; the ‘Wo lying close together are ensheathed, though I have been unable to ascertain definitely whether each has a distinct sheath or whether th lie in a common sheath, or whether perhaps one of them is not merely beneath the cytoplasmic sheath of the other. If either the St or second supposition is true, there still remains the question 172 BOTANICAL GAZETTE [SEPTEMBER whether the two cells are body cells or male cells. If the third suppo- sition is true then there are four prothallial nuclei, a generative cell, and the tube nucleus. In a number of preparations there seemed to be a cell on the side of the body cell opposite the stalk cell (fig. 27), but in no case could I satisfy myself of the presence of a nucleus; though in view of the figures published by JEFFREY and CHRYSLER it was diligently looked for. In fig. 27 is shown a mass at one end of this “‘cell,’’ which may stand for a degenerating nucleus, although I think not. . It is very indistinct and may very well be a mere aggregation of slightly denser cytoplasm. By constructing a model of the cell complex, where the body cell has sunk down between the cells of the second tier of the prothallus, and then cutting it so that the section will pass about centrally through stalk and body cell and include most of one-half of them and take a slice off the prothallial cells lying beyond them, it is possible to get preparations which show cell walls in the position shown in the figure. Hence it is not certain that in this species there are two lateral derivatives of the generative cell, as seems to be the case in the species mentioned by JEFFREY and CHRYSLER (4). The dividing nuclei of the species of Podocarpus here investigated show uniformly twelve chromosomes in cases where they could be certainly counted (figs. 14, 27, 32), and twenty-four were counted several times, with less certainty, in the sporogenous tissue of P. sp- In this it conforms to the count for all other gymnosperms S0 far as known except Taxus, with eight and sixteen (STRASBURGER 12), and Sequoia, with sixteen and thirty-two (LAWSON 7). It is not possible to speak with certainty concerning the stage at which the pollen is shed without knowing over how long a time shed- ding continues, and without actually having gathered pollen as it is shed naturally. But from cones that were apparently ready to shed their pollen, stages were obtained in P. nivalis running from ne microspore to gametophytes with two prothallial cells, generative cell, and tube nucleus. It often happens that both extremes may be ound in the same sporangium. In P. sp. no cones were apparently old enough to shed their pollen, though the oldest had essentially the same structure as those of the species just mentioned. In the set of P. totarra Hallii the range appears to be still wider, for the oldest 1908] BURLINGAME—PODOCARPUS 173 stages shown in the plates (jigs. 26, 27; text fig. 7) occurred along with the youngest. In some cases the cell walls were still intact, while in other pollen grains not more advanced, the nuclei and body cell were free in the common cytoplasm (text figs. 1, 3, 7). Discussion The facts presented in the preceding account are in the main confirmatory of those already reported by CoKER and by JEFFREY and CHRYSLER for other species of Podocarpus; hence their main value is that they offer additional evidence that the phenomena described by these authors are not limited to the species studied by them. These authors and others as well have called attention to the resemblances to the Abietineae in the winged pollen, thick sporan- gium wall, and general similarity of the staminate strobilus. The main interest centers’ about the development of the male gametophyte. CoKER (2) reported two primary prothallial cells in P, coriacea, which divide amitotically. JeFFREY and CHRYSLER (5) have recorded as many as eight in the species studied by them. Miss Younc (14) has also recorded as many as four in species of Dacrydium. THompson (13) has found 30 to 4o prothallial cells In Agathis; and LopriorE (8) has reported a cell complex in Arau- caria that reaches about 1 5 in number before the walls break down, When the freed nuclei may then further divide until as many as 44 may be found in the pollen tube. He interprets these as sperma- togenous cells and cites the case of Cupressus as analogous. CHAM- BERLAIN (2) has already called attention to the fact that the drawings seem to indicate that these nuclei are really prothallial and that there is only one body cell. In this view Miss Younc (14) has con- Curred, as it would seem most students of gymnosperms must. RE- NAULT (10, rz) and OLIVER (9) have described the multicellular Pollen grains of the Cordaitales and Stephanospermum, where as many as 20 cells are found in the male gametophyte; whether they are prothallial or spermatogenous is uncertain. Catpwext (1) has reported as many as nine or ten body cells in Microcycas, along with a single stalk and single prothallial cell. CHAMBERLATN in a forthcoming paper reports that Ceratozamia ®ceasionally has four sperms. JUEL (6) found a variable number * 174 BOTANICAL GAZETTE [SEPTEMBER of sperm cells (it is not clear whether he means body cells or male cells) in Cupressus goweniana. It thus seems to be an established fact that more than two pro- thallial cells and more than two sperms occur in widely unrelated gymnosperms. Though we may all be willing, perhaps, to accept this statement of facts, there is no such unanimity of opinion as to the interpretation of them. It is obvious that one may adopt either of two views: (1) One or two prothallial cells were found in the primitive gymnosperms and in some cases these have divided to form a complex. This would be Jerrrey’s (5) “‘coenogenetic prolifera- tion.” In support of this view he has urged that a multiplication of prothallial cells is correlated with “protosiphonogamic” fertilization in the Araucarineae, “since the length of the pollen tube, in the absence of any special conductive tissue, such as is found in angio- sperms, calls for a greater development of prothallial tissue.” This line of reasoning could hardly be extended to Podocarpus or to any other case now known. If one could find some physical cause applicable to all cases, he might believe that this multiplication of cells is a thing of recent origin in each case. Furthermore, the idea that a multiplication of cells would be forthcoming just when needed is more teleological than accords with modern physiological teaching. If we do not accept this explanation, as I think we cannot, we May turn to the other possibility. (2) Primitive gymnosperms had 4 multicellular prothallial tissue, and not unlikely a spermatogenous complex of several cells. The evidence for this view is of two sorts, historical and theoretical. Historically we know that the pollen grains of certain Cordaitales (10) and Cycadofilicales (9, 10) 11) h a considerable tissue of some sort. Whether it was spermatogenous or prothallial is not very material, since this view assumes that bot sorts existed somewhere in the ancestry of living gymnosperms 4? that by a gradual reduction each sort has been reduced to one two cells. It is of interest to note that all the heterosporous pterido- phytes show the same tendency, each of the living genera having 4 single prothallial cell and in some cases producing as few as 10UP sperms. ‘This assumption makes it easy to account for the facts already related. We have but to suppose that in these cases si forms showing these peculiarities have merely retained their primipve ie 1908] BURLINGAME—PODOCARPUS 175 characters or, in cases where they occur only occasionally, that it is a reversion to ancestral conditions. JuEL (6) has already suggested this explanation for the case of Cupressus, and has even gone so far as to suggest a possible sequence in the reduction. At this point one must be on guard against supposing that types which illustrate this reduction series necessarily, or even probably, stand in the same series phylogenetically. It seems to the writer that if this funda- mental principle be firmly grasped, it is entirely unnecessary to sup- pose that because Podocarpus and Pinus are clearly related and because Pinus is older historically, therefore the multiplication of prothallial cells in Podocarpus must be coenogenetic. One need but assume that both are derived from a common ancestral stock and that one has retained the prothallial complex and the other has lost it. Of course if one believes that Podocarpineae have come directly out of living Abietineae, this explanation would not hold. While it is true that the latter are known as far back as the Carboniferous (4) and the former are not known to be nearly so old, it is equally unde- niable that we know but little of the plant remains of those parts of the world in which théir remains would be most likely to be found. Summary 1. There are in the species of Podocarpus studied two prothallial cells which may or may not divide. There may be as many as eight prothallial cells in two tiers derived from the two primary ones. 2. Division in the prothallial tissue is mitotic and the prothallial — cells do not degenerate. _ 3. There is a stalk cell and a body cell, sometimes differing very little from one another in appearance; whether both may produce male cells is yet uncertain. 4. The number of chromosomes is twelve and twenty-four. 5. There may be a variable number of cells or free nuclei in Pollen grain at the time it is shed. the Acknowledgments are due to Professors JoHN M. COULTER wee Cc ea J. CHamBeErtatn of this laboratory for valuable advice and “riticism during the progress of this investigation. Tae Universtry or Curtcaco ; 176 BOTANICAL GAZETTE [SEPTEMBER LITERATURE CITED 1. CALDWELL, Otis W., Microcycas calocoma. Bot. GAZETTE 44:118-I41. 2. CHAMBERLAIN, C. J. (Review). Bot. GAZETTE 40:391. Igo - Coker, W. C., Notes on the gametophytes and embryo 2 Podocarpus. Bot. GAZETTE 33:89-107. pls. 5-7. 1g02. 4. JEFFREY, E.C., and —e M. A., On Cretaceous Pityoxyla. Bot. GAZETTE 42:1-15. pls. 1, 2 : , The ee of the ies ace Amer. Nat. 41:355- w 5- 364. figs. 5 1907. 6. JueEt, H. _ Ueber den Pollenschlauch von Cupressus. Flora 93:56-62. pl. 3. 190 7. Lawson, x A., The gametophytes, archegonia, fertilization, and embryo of Sequota s saiariiehs Annals of Botany 18:128. pls. 1-4. 1904. 8. Loprrore, G., Ueber die Vielkernigkeit der Pollenkérner und Pollenschlauche von deca Bidwillii. Ber. Deutsch. Bot. Gesells. 23:335-346- Pl. 15- 1g05. 9. OLIVER, F. W., On the structure and affinities of Stephanospermum. Trans. Linn. Soc. Landed II. 6: 361-400. pls. 41-44. 1904 10. RENAULT, B., Structure comparé de quelques tiges de Ia flora carbonifére. 1879. , Cours de Bot. Foss, 4:1880-1884. Paris. ~ 12. STRASBURGER, E., Anlage des Embryosackes und Poh bei der Eibe. Festschrift fiir Haeckel 1-16. pls. 1, 2. Jena. 190 13. THompson, R. B., Preliminary note on the Araucarineae. ‘Scie N. S. 22:85. I905. 14. YouNG, Miss M. S., The male gametophyte of Dacrydium. Bor. GAzeTT 44:189-196. pl. 19. 1907. EXPLANATION OF PLATES VIII AND IX The drawings were made with a Bausch and Lomb camera lucida and Zeiss apochromatic lenses and compensating oculars. The plates have been one-half in reproduction, PLATE VIII (Figs. 1, 2, 5, 7-17 are P. sp.; figs. 3, 4, 6 are P. totarra Hallit) oS Fic. 1.—Cross-section through the middle region of a staminate cone, show- ing the relative position of sporophylls and sporangia (s), vascular bun bundles (ob), and resin canals (rc); the canals sometimes branch as shown at a. Fic. 2.—Cross-section of resin canal. Fic. 3.—Cross-section of vascular bundle from strobilus; px shows P? —_ of protoxylem Fic. ‘Lengo section of a sporophyll, and one sporangium of we cone about 3™™ in length. ar —" ‘ scm ; NICAL GAZETTE, XL VT p PLATE VUI AM, GY AKAN ¥ YA y ORY OY Mit SN Y SAAN) 4 Wy atta; i 8 Saitgerens wy) Vg a * sau Ke 28s, my 32% oy +] BURLINGAME on PODOGARPUS : ANICAL GAZETTE, XLVI PLATE 1x BURLINGAME on PODOCARPUS 1908] BURLINGAME—PODOCARPUS 177 Fic. 5.—Detail of sporangium of same age as preceding, showing relations of wall, tapetum (#), and sporogenous tissue (sp). Fic. 6.—Cross-section through sporangia; vb, vascular bundle. Fic. 7.—Cell of the sporogenous tissue about one division short of the mother cell stage. Fic. 6.—Detail of a nucleus a little later than preceding, showing the nuclear materials beginning to arrange themselves into threads with here and there deeply staining chromatin knots. : Fic. 9.—Surface view of a still older nucleus showing the strands more dis- tinct and larger. Fic. 10.—The definitely organized spirem with unusually distinct chromatic knots; the spirem is usually more homogeneous and stains more evenly. Fic. 11,—A very thin section of a nucleus whose spirem is beginning to seg- ment into chromosomes; compared with fig. 7, it shows the variation in size and shape of the sporogenous cells. Fic. toe section of a cell in telophase showing about half of each group of chromosomes; the spindle is curved with the concavity toward the observer, Fic. 13.—Showing the reconstruction of the daughter nuclei. 1G, 14.—Mother cell showing the emergence of the chromosomes from the ~ gtanular mass out of which the spindle arises; the granular materials are actually much denser than shown in this figure and nearly conceal the chromosomes. 1G. 15.—Longitudinal section of the heterotypic spindle. Fic. 16.—Late anaphase of the heterotypic mitosis. Fic. 17.—The homotypic mitosis, PLATE IX oe (Figs. 18-27, 3 3 are P. totarra Hallii; figs. 28-32 are P. ner? Fic. 18.—Section of microspore slightly oblique to the wings; 7, intine; @, exine. Fic. 19.—Male gametophyte showing first prothallial cell (p:) divided, no Second prothallial (p,) cell, primary spermatogenous cell (ps), and in next section the tube nucleus (). primary FIG. 20.—Same stage as preceding except that there are here two Prothallial cells (p,), the second of which has divided (only one, 2, of the seg- ments shown). : Fic. 21.—Same as fig. 19 except that the single primary prothallial cell (p:) has not divided; #, tube nucleus. a d Fic. 22.—Male gametophyte showing first prothallial (p;) undivided, secon (?). divided once, primary spermatogenous cell (ps), and tube nucleus (2). oe _ Fic. 23.—Same as preceding except that first prothallial cell (p) has x derivatives of the second prothallial cell (p,); adjacent sections show that there are here four derivatives of the second prothallial cell. , 178 BOTANICAL GAZETTE [SEPTEMBER Fic. 24.—Showing the stalk (sc) and body (bc) cells as well as prothallial cells (p:, p2) and tube nucleus (#). é Fic. 25.—The mitosis giving rise to stalk and body cells from the primary spermatogenous cell. Fic. 26.—A usual type of mature gametophyte, having four derivatives of the first primary prothallial cell (p,), four of the second (,), stalk (sc), and body (6c) cells, and tube nucleus (é); nine cells also usual (two #:, four 2, stalk, tube). ; sae 27.—Showing the prophase of the division of the first prothallial cell (pz) and what appears to be a “‘cell” (x) on the side of the body cell opposite to the stalk cell (se); no nucleus could be discovered in this “‘cell;’’ see text for ieee details. Fic. 28 .—Division of the microspore nucleus in P. nivalis; a peculiar seg- mented appearance of the spirem, which has about completed segmentation into chromosomes, is shown. Fic. 29.—A similar but younger spirem which has not yet begun to segment as the preceding one has done. Fic. 30.—Anaphase of the division resulting in second prothallial cell (pa) and antheridium initial. Fic. 31.—Late telophase of division of antheridium initial into primary spermatogenous cell and tube nucleus; this is the usual shedding stage of this species, with prothallials undivided. Fic. 32.—Metaphase of division of uilpacitions initial showing the twelve gametophytic chromosomes; see also jig. 27. Fic. 33.—Details of nucleus of primary spermatogencus cell of P. totarra Halli. SISYRINCHIUM: ANATOMICAL STUDIES OF NORTH AMERICAN SPECIES THEO. Horm (WITH PLATES X, XI, XIA) Before the genus Sisyrinchium becomes entirely lost in segregates and in new species, which in late years have accumulated very rapidly, it might be appropriate to present some notes to demonstrate the characteristics of the genus as represented within our own boundaries. Three sections are recognized by BENTHAM and HooKER: BER- MUDIANA Adans., ECHTHRONEMA Herb. (Hypastvius Salisb.), and ERIPHILEMA Herb., based on floral structure, and especially whether the filaments are connate for their entire length or only partly so. In his work on the Botany of California Watson reached the same Conclusion, and considered these floral characters as being merely of sectional importance. But in late years some American writers have raised these sections to generic rank, though with the preference of Sisyrinchium for Bermudiana, and Hydastylus for Echthronema, and without having invented any other distinctive characters than the Hloral, already described by BentHam and Hooker, and by Watson. In fact the habit of these plants is very much alike; and strikingly so when compared with Iris, in which genus the floral structure exhibits no small modification, and besides, the habit is extremely variable; oo Tris has not yet suffered the same dissolution as Sisyrin- lum, The internal structure of the Irideae has already been studied by some authors, but not very extensively, since only the leaves have ” examined. Ross,' and CHopat and BaLicka-IwANOWSKA? have published some very interesting anatomical papers dealing with the foliar Structure of a large number of genera, but very little has 1 written in regard to our genus Sisyrinchium. The following may thus be considered as supplemental to these papers, but have included the structure of the stem and root for the sake of a om comparata delle foglie delle Iridee. Malpighia 6: 1892; and 7: 1893. feuille des Iridées, Jour. de Botanique. 1892. *79] [Botanical Gazette, vol. 46 180 BOTANICAL GAZETTE [SEPTEMBER making the anatomical diagnosis a little more complete. Moreover, I believe that the internal characters observed in representatives of the three sections mentioned above will strengthen the former view of considering Sisyrinchium as one genus, and a very natural one. The material examined consists of S. anceps Cavan., which is very frequent in sandy soil among rocks on the Potomac shore (D. C.); S. angustifolium Mill., from sandy hills near Brookland (D. Ci S. montanum Greene, from gravelly soil along creeks on Long’s Peak (Colorado), at an elevation of about gooco feet; S. xerophyllum Greene, which I found quite abundant in low pine barrens neat Eustis (Florida); S. grandiflorum Dougl., from dry hillsides in Oregon; and S. californicum Ait. {. from swamps at Bodega (Cal.). The last two species were kindly sent to me by Miss ALICE EasTwooP and Mr. THomas Howett. To these may be added the tuberous- rooted S. alatum Hook. from lava fields above Cuernavaca, Morelos, Mexico, at an elevation of 8500 feet, collected by Mr. C. G. PRINGLE. As stated above, the general habit of these species is very much the same, especially the inflorescence. This represents in = species of Sisyrinchium a rhipidium,3 and this type of monochasium is frequent among the Irideae. Whether the inflorescence is single and terminal or accompanied by a lateral, the flowers are always surrounded by green, leaflike bracts (L, L', and L’, fig. 2); @™™ branaceous foreleaf occurs at the base of the lateral inflorescence (P, jig. 2) and at the base of the axillary flowers (P?—P?, fig. 6). The successive development of the flowers may be seen in the diagt@™ (fig. 6), where five flowers (z~5) are situated in the same plane, a” where z is the terminal, the earliest developed. The various stag of these flowers are shown in figs. 3-5, but the two bracts (Lt, L’) are only indicated. The stamens, especially the anthers (St, figs: 4, 5), are much farther advanced than the outer (P*) Z perianth leaves (P?); I have found no deviation from this type i? inflorescence in any of the three sections, but the relative length ° the green bracts (L-L?, fig. 2) varies very much, and is conside ae a specific character, with no good reason, however. Bracts 3 Compare Etcuer, Bliithendiagramme 39. fig. 204. 1908] HOLM—SISYRINCHIUM 181 foreleaves, as we know, are very frequently subject to variation, sometimes in accordance with the surroundings The rhizome is usually very short and cespitose, but in some species, S. californicum for instance, the rhizome is horizontally creeping, with the internodes quite distinct. The leaves are two- ranked, equitant, and the aerial stems strongly compressed, except in S. grandiflorum, in which leaves and stems are almost cylindric. It would be interesting to know whether the species of these three sections germinate in the same way, but so far this point does not seem to have been studied. For this reason I have followed S. angustifolium, which is so very frequent in the vicinity of Brookland, from seedling to mature plant, and the structure of the seedling is as follows. The cotyledon (Cot, fig. 1) is epigeic and consists of a sheath- ing base and a long filiform blade, the apex of which remains inclosed within the seed for some time, as shown in the accompanying drawing. Three leaves (L*-L3) are developed from the plumule during the first season, and the structure of these leaves agrees with that of the later ones, being ensiform and green. The primary root (KR) grows and remains active during the first season, and becomes ramified ; secondary roots (r) develop also, and these proceed from the base of the cotyledon. It requires several years for the plant to reach the flowering stage, and until then the small rhizome remains as a mono- podium similar to Iris. This method of germination represents Kirss’ type 5,4 and corresponds, to some extent, with that Laven frequent among the dicotyledons where the seed leaves are epigelc. It is characteristic of several Liliaceae (Allium, Bowiea, Asphodelus, etc.) and of Agave, but not of Iris; in J. Pseudacorus, for instance, the apex of the cotyledon remains inclosed within the seed, and does not ome free as in Sisyrinchium. So far as the external structure of the various members of the three sections mentioned above is con- cerned, there seems no plausible reason for dividing the genus, and We shall see that the internal structure also does not warrant any such Segregation. Whatever distinctive characters have been observed are merely sectional, and it is hardly necessary to call atten- Non to the fact that much more pronounced deviations in struc- Taps ttt8e 2Ur Morphologie und Biologie der Keimung. Untersuch. Bot- Inst- 12572. 1881-1885. 182 BOTANICAL GAZETTE [SEPTEMBER ture are known in many other genera, which so far have been left intact. Anatomically our genus is not a very interesting one, but the structure has never been studied, and I thought that the following discussion of the vegetative organs might be of some interest from a comparative point of view. Some knowledge of the structure, especially since the material came from widely separated stations, may be of interest to students of plant societies, for it seems to me that many of the conclusions reached in the name of ecology are too superficial, so long as the plants themselves have not been studied thoroughly. ROOTS In our native species of Sisyrinchium the secondary roots are slender; they are soft and of a whitish color in S. californicum, but quite strong, and yellowish brown in the other species. In xerophyllum and S. grandiflorum the roots are almost villous from the dense covering of root hairs, while in the other species the roots are much less hairy. The epidermis is thin-walled, and inside this is an exodermis of a single stratum, whose cells are mostly pentago nal in cross-sections, and thin-walled in all the species except S. xerophyllum, in which the exodermis is very distinctly thickened. The cortical parenchyma contains no stereids, and is composed 0 a compact, but thin-walled tissue; in S. montanum the cortex collapses tangentially, but remains solid in the other species, and contains deposits of starch except in S. calijornicum. The endodermis shows a very pronounced thickening of the inner cell walls, thus representing a U-endodermis, but is thin-walled in S. californicum. : The pericambium consists generally of a single layer of thin- walled cells (P, jig. 8), and is continuous; however, the followine » exceptions were noticed. In S. montanum (fig. 9) there is frequently a second stratum of pericambium to be observed outside some of the hadrome rays and this same condition occurs also in S. xerophyll we (fig. 10). Sometimes the pericambium becomes thick-walled, ” may be seen from jig. rz, which is of S. xerophyllum, and in which the cells outside the leptome are quite thickened in contrast to those sl side the hadrome. In these same figures of S. xerophyllum (fiss- 10, IT) we notice also that the pericambium is not continuous, 1908] HOLM—SISY RINCHIUM 183 interrupted by the protohadrome vessels. This interruption of the pericambium was observed only in this species (S. «erophyllum), in all the roots examined, but not in any of the roots of the other species. The hadrome is very conspicuous in all the roots,-and there may be as Many as twelve rays with two or three protohadrome vessels in each ray; the leptome, on the other hand, consists of very narrow strands, in which the protoleptome cell is readily visible (PL, jigs. &-11). Although the rays of the hadrome extend to the center of the root, the conjunctive tissue, nevertheless, is very conspicuous, and is mostly thin-walled except in S. xerophyllum and in some of the Toots of S. anceps. This structure seems to be characteristic of the slender secondary Toots of mature specimens of this genus. In the corresponding roots of the seedling of S. angustijolium no exodermis is developed and the cortical parenchyma is very thin-walled; the endodermis, on the other ‘hand, is very thick-walled, representing a typical U-endo- ermis. In these young roots the pericambium is continuous, and the stele contains only two hadromatic rays alternating with two small groups of leptome. In regard to the structure of the stele, the pericambium, and the mestome, the thin lateral roots of mature specimens agree with that observed in the secondary ones of the seedling; but the endodermis is different, being thin-walled and showing the Casparyan spots very plainly (End, jig. 16). The structure of the roots of these species is thus very uniform, and the only distinction seems to depend upon the structure of the Pericambium, which sometimes consists of more than one stratum, and which may be interrupted by the protohadrome, as observed in S. xerophyllum from subtropical Florida. In the tuberous roots of the Central American S. alatwm Hook. the Cortical parenchyma represents a very large parenchyma filled with starch, and with the cell walls thickened; but otherwise the Structure of epidermis, exodermis, endodermis, and pericambium, Which is continuous, is identical with that of the species described above. The number of hadromatic rays averages about twelve, and Pe kitome occurs as exceedingly nartow strands in these tuberous S. : 184 BOTANICAL GAZETTE [SEPTEMBER RHIZOME S. calijornicum is the only species examined that possesses a hori- zontally creeping rhizome with the internodes distinct. The struc- ture is rather weak when compared with that of the rhizomes of the monocotyledons in general, since no stereome is developed. The epidermis is thin-walled and covers a cortex of broad, compact parenchyma; the endodermis is thin-walled, and the cells somewhat irregular in shape. Inside the endodermis is a large, thin-walled pith, in which the numerous mestome strands are located, but without being arranged in bands; most of these mestome bundles were observed to be leptocentric, the leptome being more or less com- pletely surrounded by the hadrome. STEM ABOVE GROUND With exception of S. grandiflorum the stem is ancipital, simple, or sometimes branched above; the wings vary somewhat in breadth, but the central portion of the stem is always cylindric, and of a very firm structure, due to the presence of a solid sheath of thick-walled stereome. The cuticle is frequently thick and wrinkled, and cell walls of the epidermis are prominently thickened, especially the outer, and very often extended into short papillae, but not in J. californicum. In the body of the stem as well as in the wings the cortex is composed of palisades and represents a very compact tissue, but in S. californicum the cortical parenchyma is more open and the cells very short, almost roundish in transverse sections. There is 20 hypodermal collenchyma or stereome in any of these species, and the stereome constitutes, as stated above, a closed sheath of several strata located on the inner face of the cortex in the cylindric portion of the stem; in the wings the stereome accompanies the larget mestome strands as small groups on the leptome side. The mestome bundles are arranged in two concentric bands in the cylindric part of the stem, but in a single plane in the wings. They are collateral, and those of the peripheral band are very small, and contain mostly leptome; they are located in the cortex, but their hadrome touches the stereomatic sheath. Those of the inner band are much large and are located directly inside the stereome cylinder, with sage hadrome bordering on the pith. The innermost part of the cylinder 1908] HOLM—SISVYRINCHIUM 185 is occupied by a pith, which is frequently somewhat thick-walled and solid. In the wings the mestome strands are few, and they show mostly the same position of the hadrome, which is turned toward the center of the stem; it is only the marginal mestome strands that differ in this respect, the leptome and hadrome being vertical on the surface of the wings, instead of parallel. In S. grandiflorum the structure of the stem is somewhat different ; the outline is less compressed and there are many deep furrows. These furrows contain cortical parenchyma, and the peripheral band of small mestome bundles is located in the ridges, thus imbedded in the cortex and removed from the stereomatic sheath. The inner band of mestome bundles, on the other hand, is located inside the stereome, as in the other species described above. The structure of the stem is thus very uniform in these species of Sisyrinchium, and it seems characteristic of the genus that no hypo- dermal mechanical tissue is developed; that there is a strong sheath of stereome Separating two concentric bands of mestome bundles, of which the peripheral are of the same size and much smaller than the inner ones; furthermore, the winged stem of most of these species constitutes also a very conspicuous feature. LEAVES The foreleaves are membranaceous, almost destitute of chloro- phyll, and strongly compressed from side to side; they are frequently scabrous from thick-walled papillae (fig. 12), but only on the dorsal face. The cuticle is smooth, and the epidermis is moderately thick- walled on the dorsal face, but thin-walled on the ventral. There is oe chlorenchyma in the middle portion of these leaves, and it con- “sts of roundish cells throughout, with very little chlorophyll; the broad and very thin margins of the foreleaves consist only of epi- dermis, that of the dorsal face. The stereome is very poorly repre- sented; it occurs as two very small, hypodermal strands, one on each Side of the ventral sinus above the midrib, and the veins have a few layers of this tissue on the hadrome side. There are several mestome Strands in these leaves (3 to 8) and the midrib is usually a little thicker than the others; the mestome strands are collateral, and surrounded a parenchyma sheaths. While the leptome is well developed in 186 BOTANICAL GAZETTE [SEPTEMBER all the veins, the hadrome is frequently absent, except in the midrib. The green leaves are sheathing, and provided with a long, strongly compressed blade, the structure of which is very markedly isolateral. By examining the anatomical structure of the blade one gets the impression that the peculiar position of the leptome and hadrome in the veins is due to a concrescence of the two halves of the leaf-blade, resulting in a more or less complete suppression of the morphologically ventral face of the blade. However, the development of the ensiform leaf of Irideae, as de- scribed by GOEBEL,‘ teaches us something very different. According to this author the singular shape and structure of the blade is caused not by a concrescence of the wo halves of the blade, but by the peculiar growth of the leaf-primordium. The young leaf becomes laterally compressed at a very early stage of its development, and it so happens that its dorsal face shows this flattened growth much more than the ventral. The real growing-point soon ceases to be active, while a new point takes its place and this is located on the extreme back of the primordium, and somewhat lower than the original. The leaf thus shows two apices, and the secondary of these grows out into a long bladelike organ, which consequently has no ventral face, and in which the arrangement and structure of the veins must follow other laws than in a normally developed leaf-blade. The real apex of the leaf is thus to be found at the upper part . the open sheath, while the bladelike organ represents merely @ secondary growing-point, which has surpassed the primary one. In the species of the section Bermuprana the leaf-sheath is usually much shorter than the ensiform blade; in the section ECHTHRONEM* on the other hand, the sheath may be traced to very near the apex of the blade; and finally, in the section Errexiiema the blade is less compressed and often much shorter than the open, sheathing portion of the leaf. It is interesting to see that although the leaves ilk ensiform in all these species, the internal structure nevertheless exhibits two types so far as concerns the disposition of the mestome strands, which are in a single plane, as in BERMUDIANA, OF in th parallel planes, as in the two other sections. But otherwise the 5 In ScHENK’s Handbuch der Botanik 219. Breslau. 1884. 1908] HOLM—SISY RINCHIUM 187 structure is rather uniform, and the few distinctions which I have observed seem to be of merely specific importance. Beginning with section BrrmuprANA, the leaf-blade is smooth in S. anceps, but furrowed longitudinally in several of the other species, as S. angustifolium, S. bellum, etc. The surface varies from perfectly glabrous to very prominently scabrous, and it deserves Notice that the leaves may exhibit both structures when examined at different places. The apex may be very scabrous, for instance, in contrast with the lower parts of the blade, or sometimes vice-versa; or some of the earliest developed leaves may be more glabrous than the succeeding. I mention this since the characters “glabrous” and “scabrous” figure so very conspicuously in the recently published diagnoses of “new species of Sisyrinchium.” The cuticle is thick and distinctly wrinkled. The epidermis is frequently thick-walled, especially the outer walls (figs. 13, 15, 20, 21); and, as stated above, the extension of epidermis into papillae of various forms, pointed or obtuse, is common to several members of the genus (fig. 21). The stomata are arranged in longitudinal lines on both sides of the blade, and they are sunk (fig. 13). It is interesting to notice that in the subtropical |S, xerophyllum (from Eustis, Florida) the thickness of epidermis reaches its maximum (fig. 15); the cell walls are extremely thick and porous, but no papillae were observed in this species. In regard to the chlorenchyma, we have in this section a more or less typical and compact palisade tissue of several layers, the inner- ‘Most of which forms circular bands around the mestome bundles, with the cells radiating toward the center; while in the peripheral (hypodermal) strata the palisade cells are vertical to the epidermis. In some species, for instance S. anceps and S. xerophyllum, the chlorenchyma breaks down and forms lacunes between the veins, especially in the latter species. The mechanical tissue in the genus 1s only Tepresented by stereome, which accompanies the mestome bundles as a small cover on the leptome and hadrome side; but it S Not very thick-walled except in S. xerophyllum, and it does hot occur as isolated, hypodermal groups in any part of the leaf. It occupies the somewhat unusual position of being located inside the thin-walled, chlorophyll-bearing parenchyma sheath, which 188 BOTANICAL GAZETTE ~- [SEPTEMBER surrounds each of the mestome strands. However, this parenchyma sheath differed from similar sheaths in other monocotyledons by showing no resistance when treated with concentrated sulfuric acid. The arrangement of the mestome strands is very peculiar, and especially the disposition of leptome and hadrome. From the fact that the blade is not a blade in the proper sense of the word, but an outgrowth of the dorsal face, hence with no ventral face developed, the course of the veins is different from that of leaves in general. If we examine a cross-section of the blade we notice at once that all the mestome strands occupy a single plane, extending from the one margin of the blade to the other; also that the mestome strands show a different position of leptome and hadrome in relation to the periphery of the section. Those near the center of the blade are the largest, and in these the leptome turns alternately with the hadrome to the right or left of the longitudinal axis of the leaf; in this way, by examining the two sides of the leaf, we find in one mestome strand the leptome turned toward the right, in the next toward the left, etc.; and the same alternating position is of course also occupied by the hadrome. But the small strands, which are located in the thin margins of the blade, show almost constantly the leptome turn- ing toward the edge of the leaf, and the hadrome, on the contrary, toward the center. In other words, the structure of the blade looks as if the two halves had grown together, but we know from the development of the leaf-primordium that no such concrescence has taken place. The mestome bundles are collateral and show the ordinary structure; anastomoses are not infrequent, and they form very acute angles with the larger veins, as in Eriocaulon for instance. The leaf structure is thus very uniform in this section, and the most conspicuous variation seems to depend upon the thickness of the epidermis, and upon whether the chlorenchyma forms typical ee sades (jig. 20), or consists of short, almost roundish cells, 4s in - anceps (fig. 21). In S. grandiflorum (section Ertputtema) the leaf structure differs very conspicuously from that of the former section, and resembles much more the structure of a stem than of a foliar organ. In er species the leaf is less compressed; the mestome strands constitute # narrow elliptical band, instead of being located in a single plane 1908] HOLM—SISY RINCHIUM 189 also the central portion of the leaf contains a thin-walled, colorless tissue very much resembling the pith of a stem, and is frequently hollow. Otherwise the structure of the tissues is identical with that of several species of the former section (BERMUDIANA). ‘The cuticle is thick, but smooth; the epidermis is papillose, moderately thick- walled, and the chlorenchyma is composed of palisades, which are vertical to the epidermis but very open from wide intercellular spaces. The stereome is rather thin-walled, and shows the same distribution as in BERMUDIANA, The leaf is very distinctly furrowed longitudi- nally, and the mestome strands, which are of two sizes, are arranged alternately so that the smaller are in the furrows and the larger in the ridges. All the mestome strands turn the leptome toward the periphery of the blade, while the hadrome borders on the thin-walled parenchyma, which fills the innermost portion of the blade, thus resembling a pith in respect to structure and position. In the section Ecururonema the principal structure of the blade agrees better with that of ERIPHILEMA than of BERMUDIANA; because the mestome strands are here also in a very narrow elliptical band with the hadrome turned inward and bordering on a central, thin-walled parenchyma. In S. californicum the cuticle is thin and smooth; the epidermis is relatively thin-walled and perfectly glabrous. The chlorenchyma (fig. 18) shows no palisades, but is composed of a homogeneous tissue of oblong to roundish cells (in cross-section) ; however, a superficial section of the blade (fig. 17) shows the cells of the chlorenchyma very distinctly stretched and lobed, not parallel with the longitudinal axis of the leaf, but vertical to it. In this way the chlorenchyma shows actually the structure of a pneumatic tissue, as this js developed in the dorsal portion of leaves; the central part of the chlorenchyma in this species is also a colorless, thin-walled parenchyma. No stereome was observed, and the mestome bundles are in a narrow elliptical band; they are collateral and surrounded by thin-walled parenchyma sheaths. Lae is is in brief the anatomical structure of these species of Sisyrin- chium, and bearing in mind that representatives of each of the three sections have been examined, it appears to me that the genus 1s a very natural one, and that it ought not to be divided. In regard to the morphological structure of the shoot, I have not been able to Igo BOTANICAL GAZETTE [SEPTEMBER detect any character that seems peculiar to these sections; on the contrary, the rhizome, the leaves, and the inflorescence are very uniformly developed, and the only distinction depends upon the floral structures which were mentioned in the introduction. If these floral structures were accompanied by differences in the development of the shoot, and also by peculiarities in the internal structure, there might have been some reason for dividing the genus. There are several very peculiar looking species in Mexico, and these ought to be examined anatomically from fresh material. Until then it seems most advisable to leave the genus intact. Finally, I wish to add a few words in reference to the structure of the chlorenchyma in other genera of the Irideae. We have seen the chlorenchyma in the sections BERMUDIANA (fig. 19) and ERI- PHILEMA is more or less differentiated as palisades, while in ECH- THRONEMA this tissue is composed of oblong cells parallel with epidermis; moreover, that the cells in ECHTHRONEMA are lobed, resembling those of a pneumatic tissue. These structures occur also in other genera, and for the sake of making a comparison I examined some of them. In Iris, for instance, we find in J. cristata Ait. (fig. 22) a structure of the chlorenchyma which corresponds well with that of Sisyrinchium californicum, but the cells of which are branched rather than lobed, thus representing a typical pneumatic tissue. In Iris verna L. and I. julva Ker., on the other hand, there are typical palisades, which, however, show the same direction, being parallel with the epidermis and vertical to the longitudinal axis of the blade; ™ I. xiphioides Ehrh. the palisades are vertical to the epidermis. — structure that corresponds with that of Iris verna is furthermore characteristic of Tapeinia magellanica Juss., Freesia rejracta Klatt., and Tritonia sp. In Belamcanda chinensis Adans. the chloren- chyma has a very irregular structure, the cells varying from oblong and entire to more or less deeply lobed. We have thus in Ins * varied a development of the chlorenchyma as was observed in Sisyt™ chium. I have also pointed out the somewhat peculiar arrangement - the mestome strands in Sisyrinchium (the single plane in BERMU- DIANA, and the narrow elliptical band in Errxmema and : THRONEMA). That such variation in the position of the mestome 1908] HOLM—SISY RINCHIUM IgI bundles is also observable in other Irideae may be seen from the descriptions and figures in the work of Ross cited above. It is really surprising to see the polymorphic structure possessed by Iris. In J. alata Poir. the leaves are perfectly open, not ensiform, and the veins show exactly the same position as in a typical linear leaf of grasses, for instance; in species with ensiform leaves we notice in J. joeti- dissima L. the mestome strands forming. a narrow ellipse; in J. juncea Desf, they are arranged in an almost circular band; in J. reticulata M. B. the band is quadrangular; and finally in I. japonica Thunb. the structure is like that of section BeRMUDIANA. A very striking variation occurs in Gladiolus, where the outline of the section varies from linear to cross-shaped with a corresponding variable position of the mestome strands. These modifications in structure are very striking, and moreover they are in several cases accompanied by distinct external characters, floral or vegetative; nevertheless they are not looked upon as being of anything but specific spi Ne an opinion which no doubt is the most natural. In regard to the almost untold number of recently desided “species” of Sisyrinchium, I have examined the internal structure of some of these, but so far have failed to detect any character that might appear specific; and moreover it seems very evident, when the diagnoses of the majority of these are read, that they deal not with “species” but merely with “local forms.” Brooxtanp, D.C. EXPLANATION OF PLATES X, XI, XIA PLATE X Fic, x —S, angustifolium: seedling, showing cotyledon (Cot) with seed still attached; R, prima ry root; r, secondary roots; L*-L3, the first leaves succeed- ing va cotyledon. Naidral size. Fide GS. 2.—S. anceps: young inflorescence; L-L?, green bracts; digas illary inflorescence. Natural size. b s 3-—S. anceps: inflorescence, the terminal of fig. 2; P*-P?, — ~~ > Breen bracts. Magnified. Flos. 4, 5.—s. anceps: two youngest flowers of same inflorescence; P*, , inner perianth; st, stamens. Mi 3 was 1G. 6.—S. anceps: diagram of a five-owered i fl Tis the first developed; the other letters as above. ce; F-5, the flowers, 192 BOTANICAL GAZETTE [SEPTEMBER Fic. 7.—S. alatum: cross-section of root; C, cortex; End, endodermis; P, pericambium; three rays of hadrome and two strands of leptome are figured. X 320. PLATE XI Fic. 8,—S. anceps: cross-section of root; PH, protohadrome; PL, protolep- tome; the other letters as in fig. 7. 406. Fic. 9.—S. montanum: cross-section of root stele; letters as above. 496. Fic. 10.—S. xerophyllum: cross-section of root stele; letters as above. X496. Fic. 11.—S. xerophyllum: cross-section of root stele; V, vessels; the other letters as above; many of the pericambium cells are thick-walled. 496. Fic. 12.—S. angustifolium: epidermal projection from the foreleaf. 240. Fic. 13.—S. angustifolium: cross-section of the stoma from the leaf. 496. Fic. 14.—S. angustifolium: a stoma seen from above. X 499. . Fic. 15.—S. xerophyllum: cross-section of leaf; C, cuticle; Ep, epidermis. PLATE XIA Fic. 16.—S. montanum: cross-section of a thin lateral root; letters as above. 096. Fic. 17.—S. californicum: chlorenchyma of leaf, seen from above. : Fic. 18.—S. californicum: cross-section of part of leaf; Ep, epidermis; PS, parenchyma sheath of mestome strand. Fic. 19.—S. montanum: chlorenchyma of leaf, seen from above. 240. Fic. 20.—S. montanum: cross-section of part of leaf; St, two stomata with their air chambers (A); the other letters as in fig. 18. X 320. IG. 21,—S, anceps: cross-section of part of leaf; Ep, epidermis; both leptome and hadrome have a support of stereome. 496. Fic. 22.—Iris cristata: chlorenchyma of leaf, seen from above. 240. — OTANICAL GAZETTE, XVI PLATE « ee o i O * es 4 ryt 6 A \ ‘6 ary \ - oy Tit ’ Wes 3 a HOLM on SISYRINCHIUM ANICAL GAZETTE, XLVI S d ae LI ¥ ¥en mot 1) i a, C5 LOVIN OR Oats ROR xO} 06 a PLATE XIA pale 30TANIGAL GAZETTE, XIVI OST} i FORG a & B bse ©) BrO)2\6 ei eea~-fN SOO OSs ee DD - *' s MD Ss he 29) aeons.) : OxG)> : ‘1 yw yoy ma a H\ HOLMon SISYRINCHIUM, — A NEW RESPIRATION CALORIMETER GEORGE J. PIERCE It is generally known that heat is liberated, often in great quantity, whenever germination or fermentation takes place under such con- ditions that only a small proportion of the heat liberated is lost by radiation. For example, in the malting of barley, it is necessary to take precautions lest the temperature of the germinating grain rise too high; and California wine-makers have repeatedly told me that they are obliged to watch the temperature of the must very care- fully lest the fermentation go too fast and “the yeast burn.” Brewers and distillers are aware of the same fact. Botanists generally lecture about the liberation of heat in the spathes of aroids, but how many of us have seen an experiment demonstrating this phenomenon? I, for one, do not recall ever having seen one. I find that a considerable number of naturalists associate these various instances of heat libera- tion with rapid growth, and in some laboratory manuals of plant Physiology the liberation of heat is treated in connection with growth Phenomena. These same naturalists, and a good many others, think of respiration not only as involving an intake of oxygen (which 's not always the case, as for example in anaerobic respiration), but © an outgo of carbon dioxid. This latter is by no means always the case, as the respiration of the sulphur, iron, and certain nitrogen bacteria shows. The intake of oxygen and the outgo of carbon dioxid are the easi- est features of the process of respiration to demonstrate in the organisms ordinarily studied in those biological laboratories in which any atten- ton whatever is paid to live plants or animals. It is easy enough for Us all to go on thinking of respiration as a sort of ventilating process, IN which a poisonous waste product of the living organism is dis- Placed or replaced by a useful gas. We do not necessarily realize how this latter gas is useful, except as it takes the place of another which 'S Poisonous. Whether carbon dioxid is itself poisonous is, I suppose, °pen to dispute. At any rate, it is ordinarily of no use to the organism. 193] [Botanical Gazette, vol. 46 194 BOTANICAL GAZETTE [SEPTEMBER It can be used only as a food material, only by chlorophyll-containing cells, and by these only in the light. The other features of the process of respiration are hard to demon- strate, hard even to study. The chemistry of respiration is scarcely less difficult than the chemistry of photosynthesis.t Whatever the reactions may be in the chain which connects the free oxygen of the air with the oxygen combined with carbon or iron or sulphur, etc., it is clear, on theoretical grounds, that the oxidation or oxidations which take place must liberate heat. The demonstration of this fact, with reasonably small quantities of living organisms, has hitherto been nearly impossible. For this reason, it has been almost useless for the teacher to insist that the liberation of heat, the setting-free of energy, and not the material products, is the essential end, the funda- mental characteristic of respiration.? The apparatus of BoNNIER,? which has furnished the most satis- factory results so far in the study of the heat-yield, is too elaborate and too costly for most botanical laboratories. On the other hand, the simple appliances described and figured in the laboratory manuals are useless, for they do not illustrate the subject, but mislead the student. Using the ordinary apparatus and the usual quantities of live and dead peas, for example, one obtains, with good luck, 4 differ- ence of o°5 C. between the live and dead peas in the course oF twenty-four hours, or perhaps a whole degree, or, best of all, 1°5- This is mortifying enough, but if the temperature of the laboratory fall much, so that all the peas are chilled, there will be practically no difference at all. The evidence of the experiments, therefore, 15 all against the teacher who would have it that respiration is the gees of supplying the living thing with the energy it needs to do its ba paaiad Evidently the trouble is with the insulation of the vessels in which the respiring and the dead plants or parts are contained; for if radiation and absorption were reduced to a minimum, the live and — peas would certainly grow warmer, while the dead peas W® remain at the same temperature or grow slightly cooler. t See BARNES, C. R., The theory of respiration. Bor. GAZETTE 39:81-98 19° ? See, for example, Petrce, G. J., Textbook of plant physiology, chaP- er vit 3 Bonnier, G., Recherches sur la chaleur végétale. Ann. Sci. Nat. 18: 1893. 1908] PIERCE—RESPIRATION CALORIMETER 195 Convinced of this, as well as thoroughly dissatisfied with the insu- lating appliances which I had or could make in the laboratory, I went to my friends in the chemical laboratory of this university, told them of my difficulty, and asked for suggestions. Professor YOUNG, professor of physical chemistry, suggested trying some Dewar flasks. I take this opportunity to acknowledge my indebtedness, and to express my gratitude to Mr. Younc, for his suggestion is one which will be appreciated by any physiologist who tries the apparatus for this purpose. Dewar glassware is made in several shapes—cylinders, cups, and flasks. The flasks are made either tubulated or with closed round bottoms. The Dewar apparatus is made also silvered or unsilvered. The principle is si mple—double-walled vessels with the air between the two walls exhausted. Thus there is a receptacle surrounded more or less completely by a vacuum. Across this vacuum radiation or ab- sorption will take place at a rate inversely proportioned to the per- fection of the vacuum. If the walls of the vessel are silvered on the surfaces bounding the vacuum, the efficiency of the insulation will be greatly increased. The apparatus was devised for liquid-air exper- tments and is named for the inventor, the famous chemist at the Royal Institution in London. This double-walled glassware has now Come into commerce and may be bought, under the name of “ thermal bottles,” in drug stores and of the dealers in automobilists’ and campers’ supplies. It is used for keeping food or drink warm or cold, as may be desired, for many hours. Thus soup, milk, coffee, ce-water, etc., can be maintained at the desired temperature for ‘stonishing lengths of time. The commercial bottles are protected against breakage by cases of metal or basketry, but since these do not improve the insulation materially, they are unnecessary in the laborato » and the thinner-walled scientific apparatus is much cheaper, besides being obtainable in a greater variety of shapes. In the experiments which I am about to describe, I used silvered Dewar flasks of about 250°° capacity, which were supplied by EIMER and Awenp of New York for $2.40 each. If imported duty free, as they Would have been had I not been impatient to use them, they would have Cost decidedly less. There should be at least two such flasks, fot it is desirable to use always a lot of dead or other check material 196 BOTANICAL GAZETTE [SEPTEMBER for comparison; but it is naturally better to set up the experiment in duplicate and thereby reduce the sources of error. In many instances I used three flasks of live material and one of dead. Since the effi- ciency of each flask as an insulator depends upon the completeness of the evacuation of the space between the walls and upon the silvering it is evident that the flasks themselves will not be exactly alike, and that an average result is likely to be better than any single one. If proper pains are taken, the efficiency of each flask can be determined in advance; but unless the experiments are conducted in a constant temperature, as they should be, there is little use in doing this. Miss BertHA A. Witz, a graduate student and assistant in physiology in this university, did most of the actual work of setting up and recording the results of these experiments; but as we have worked constantly together, the experiments are ours rather than the work of either one of us. As the work progressed, experience showed us how the experiments should be improved in method, but the reasons for these improvements will be more evident if I describe one. Experiment 1.—An unweighed quantity of dry peas was soaked for 24 hours in tap-water. They were then rinsed in boiled distilled water two or three times and divided into two unequal lots, the smaller of which was then covered with a fairly concentrated aqueous solution of corrosive sublimate for at least half an hour in order 1 kill these peas. The other lot was divided into equal parts, which were poured into two Dewar flasks of about 250° capacity, the one silvered, the other unsilvered. The dead peas were poured into another silvered flask of the same size. The flasks were cotton plugged and suspended on strings (not wire), in such a manner that they would not touch any object, metallic or other. This was done to avoid the changes in temperature which might otherwise result. A thermometer reading only to degrees was pushed through the cotton so that the bulb was as nearly as possible in the center of each mass of peas. The data will be found in the accompanying (p. 197). Various things are evident in this first rough experiment. continued for nearly nine days and, in spite of the fluctuating ®" perature of the room, the temperature in the silvered flask contaimné live peas rose until the last day very steadily. Comparing this ™ It was g tem- 1908] PIERCE—RESPIRATION CALORIMETER 197 the temperatures recorded for the unsilvered flask, containing live peas, and with the silvered flask into which dead (killed) peas had been placed, one sees at once the superiority of the silvered flask as an insulator, and also that there was liberated and retained in the silvered flask containing live peas a very substantial amount of energy in the form of heat, even within the first twenty-four hours. Even the unsilvered flask gave a result better than I had ever been able to obtain with the ordinary insulators available in the laboratory. : ‘emp. live peas |Temp. dead peas . live as Date : silvered silvered — Tee ee Ree ee Feb. 26, 4:30 p.u.......... 17 17 at AM ee: 19 16 13 Ds” Siem 20 16 16 a eect 23 17.5 se yh Me 32 15-5 15-5 6 Ce 33 16 a ee eee 36 16 ~ OTRO BM 38 15 ) 73 °5 CL” eee apelin 39 15 ies oe Le. tee eee ° I 49 Mar. 1, 10:30 A.M reer 8 : 17-5 ~s 2, 10:20 A.M 45 14 15 = ee ee eee 47-5 14 18 ie ES 3 ee ee 49 14.5 sts 2 Oe 3 14 15 es ee OM ee 4 15 bid mit oe os. at+ 15-5 - ie me a eee 4:5 15 se or te eee. s+ 15 23 a:50 PSE 6 15-5 23 7 ee 4 14-5 = P2520 OMe, 4 Pape WiGooam, ....... ° 14 a4 STS arn When the experiment was stopped on the ninth day, because the temperature had begun to fall, it was at once evident that fermentation been very active for some time. It was inevitable that this should be so, for I had not taken the slightest pains to sterilize any- thing. But in fermentation and decay heat is liberated, for these are Processes in which respiration, as well as nutrition, takes place. We have here, then, the heat liberated in the respiration of the peas and of other organisms in the flask. The obvious thing to do in suc- ceeding experiments is to sterilize the peas and everything else used in the €xperiment, and to make similar experiments to determine the heat liberated by various ferment organisms. This I have done, to a 198 BOTANICAL GAZETTE [SEPTEMBER very limited extent and only as a preliminary, with Fleischman’s “‘compressed yeast,” as will be shown later. This first experiment, with all its roughness, seemed of sufficient importance to repeat several times in order to be quite sure that there was no mistake about it. The results were similar in every respect, and I do not need to record them here. The following experiment shows the effect of some of the improvements suggested by the pre- ceding. Experiment 2.—Into each of six Dewar flasks of approximately equal capacity, which had been sterilized by being washed with a saturated aqueous solution of corrosive sublimate and rinsed with boiled distilled water (sterile), 80%™ of air-dry peas were put. The peas and the flasks were then sterilized by shaking the peas Very thoroughly in the flasks with a 1:500 aqueous solution of corrosive sublimate, and this was rinsed off with two wash-waters, both steril- ized. Fresh sterilized distilled water was then poured into the flasks and the peas soaked in them for twenty-four hours at a temperature which ranged from 20 to 22° in the oven in which I had placed the flasks. I did not take the temperatures in the flasks during this time, as my apparatus was not then so arranged as to make that possible. However, I shall repeat the experiment under constant temperature and with readings from the beginning. The data will be found in the accompanying table (p. 199). In this experiment fermentation and decay were reduced very greatly, though perhaps not as completely as possible. Therefore we have a very fair index of the amount of energy in the form of heat which 80%" of peas (weighed air-dry) can liberate in some- thing less than three days. We also see that, in all probability, the efficiency of the individual Dewar flasks varies considerably. *° efficiency of each flask should be determined and recorded. I have not done this because it would be useless unless pains were also taken to conduct the €xperiments in a constant temperature, and this I was not able to do at that time. I shall repeat the experiment under uniform conditions as soon as possible to arrange it. The ther- mometers used in this experiment were good ones, reading to tenths of a degree, loaned to me by the department of physiology of this university, and I take pleasure in thanking my friend Professor 1908] PIERCE—RESPIRATION C. ER 199 Date Time Flskr | 2 | 3 | 4 |aeSge| © | (00m |Max.| Min. Apr. 29..... 6:00 P.M. | 2297 C. | 21°96} 22°91} 22°4) 22°%0| 2293] 19°5 Wy 30... OsL5 AM. (| 23.7 22.3] 23.8] 23.8) 18.2) 23.0 Lavih PA | 2A 9 23.1| 24.8] 24.5| 18.3] 24.0] 20.5 5:30 P.M a7 .0 25.7| 27.3| 27.4] 19.6] 26.5] 21.0 LS 3 eater 8:15 A.M. | 31.1 31-7| 32-4] 32-4] 17-4] 31.3] 14-5 12:30 P.M. | 32.3 33-5| 33-9] 33-8] 17-7| 33-0] 18.2 a ie eve: 3-4 35-1| 35-3} 35-0] 18.2) 34.5) 19-0|27-5/14-4 Moyea. 8:45 A. 20.9 38.4] 39.0] 37-5] 17-6] 37-5 12:30 P.M. | 30.2 39-5] 40.2] 38.5] 18.0) 39.0 3:50 P.M 36.8 40.5] 41.4} 38.8} 18.4] 40.0) 18 3\26.2|16.1 Experiment stopped at 3:50 P.m., May 2. | Flask 1 2 2 4 | 5 | 6 | No. peas decayedf. 3 2 | 4 2 ° 3 | Radicles 2.5-3°™ long. OC eee eli | ae Ss a Some of the sprouted peas planted in soil all grew normally. 2 Tha + ked dead were killed as in e: : + These decayed peas were without exception weevily, and because of the boreholes of the weevils could not be sterilized. Since the weevils close the outer ends of the holes, it is impossible to detect all the weevily peas when working with iderable quantitie: MacFartanp for his help in this particular respect as well as in others. Owing to the position of the thermometers, making uniform sighting impossible, I do not record the attempt to read to fractions of tenths of degrees. To see whether the heat liberated by a small amount of yeast ina small volume of a fermentable solution could be measured by the method described in the foregoing pages, I carried on some experi- ments, only one of which I need to report now. The yeast used was “Golden Gate compressed yeast,” which is, I believe, only one of the many local names for what passes in the east under the name of Fleischman’s compressed yeast. Four flasks were sterilized by being washed thoroughly with a saturated aqueous solution of Cor Tosive sublimate. They were subsequently rinsed twice with sterilized water and plugged with cotton. Into each of these flasks 250°° of tO per cent. solution of cane sugar were poured as quickly as possible. The solution had previously been sterilized in four cotton-plugged asks, from each of which it was poured into a Dewar flask. Since the yeast to be added is by no means a pure culture, I thought this Sufficient care to exercise with the solution. To three of these Dewar 200 BOTANICAL GAZETTE [SEPTEMBER flasks approximately 4.5%™ of a yeast cake were added, to the fourth flask nothing. The yeast had been quickly rubbed up in a sterilized mortar, with a sterilized pestle, in a small quantity of the sterile sugar solution. Thus, on shaking the flask after adding the yeast, I hoped to mix the yeast thoroughly with the whole volume of fer- mentable liquid. The fourth flask contained, then, only sterilized sugar solution, which had been exposed to the air for only a moment in transferring it from one sterilized vessel to another. The data follow. Date Time Flask 1 2 3 4 Room temp. no yeast) Art Oye: 6:00PM. | r9%rC.} 18°6 18°6 738 Apt 955250: 9:15 A.M. Cr ee 4 20.5 aI.t 17-5 ‘ : 5:30 P.M. 23.3 21.5 22.3 17-7 oy PAR 10. oa 8:00 A.M. 24.2 20.6 23.0 17-2 15-3 12:30 P.M. 24.5 20.8 23-4 ed a? Apa 2055 3... 8:15 A.M. 25.0 20.6 24.0 17-3 12:30P.M. | 25.1 20.7 24.2 17-4 20:2 At this point, two days and eighteen hours after the experiment was started, it was ended and the flasks opened. The odor and flavor of the solutions were pleasant. I used the same thermometers as in the preceding experiment, but for the reasons previously given record here nothing less than tenths of degrees. Of course the ther- mometers were sterilized, by standing in saturated corrosive sub- limate solution, and afterward washed in sterile water, before being introduced into the flasks. The efficiency of a good Dewar flask as an insulator is indicated by flask 4 in this experiment; for although the temperature of the room varied at least 5° C., as the record shows; the temperature within this flask varied only 0°6 C., according to the readings taken at the same times. Whether flask 2 was a poor on or whether the yeast was poor, or what the trouble was, I do aie know. In the other two flasks the mercury rose to a degree which surprised me, considering the small amount of yeast sown jn each of the three flasks and the small volume of fermentable liquid. This rise in temperature indicates the liberation of considerable enetsy in the form of heat. In connection with these experiments on the respiration of healthy 1908] PIERCE—RESPIRATION CALORIMETER 201 plants I made one experiment, purely preliminary like the others, on wounded plants. RIcHARDs reported in 1896 and 1897, as a result of his experiments, that plants develop fever on wounding, as animals do. This increase in temperature is due to increased respiration in both sets of organisms. RicHarps’ methods are excellent, but unless an efficient insulator is used or the experiments are carried on in a constant temperature, they are not absolutely exact. I deter- mined, therefore, to try Dewar flasks in a simple experiment of this sort. ‘Two lots of onion sets (seedling onions) were carefully skinned, thus removing much if not all of the dead tissue by which these young bulbs are surrounded. Each lot was found to weigh 1118™ after skinning. One lot was put whole into a sterilized flask (no. 2), care being taken that the onions were not scratched or bruised in being put into the flask. The other lot was cut into irregular pieces, each onion into four to eight pieces, with an ordinary and fairly dull 2 and put into another flask (no. 1). The temperature record ollows. Dae rae | Tae | Toke | ee OE ae April 26 ° ° 17°0 A pe eae 2:00 P.M, L755 c- 17-50 fe “is «inde ¢ Pog a 10:20 A.M. med 18.50 19.0 1:30 P.M 25.00 19.50 sighs ; 00 P.M 27.00 20.25 : Cs eae eres 12:15 P.M 38.00 20.50 ae The experiment was stopped at noon, when it had run nearly two days, and the contents of each flask turned out upon the table. Both lots of onions appeared to be in perfectly normal condition. In some cases the edges of the cuts of the wounded onions were a little “Y: The material looked as if the experiment could have been con- tinued for twice this length of time without decay or other disturb- ance setting in. It would seem, therefore, that these flasks can be used for such experiments on wounded plants. An the experiments here reported, temperatures are given as the evidence that energy (heat) is liberated in respiration. Although “se temperatures are interesting, they do not give us any idea of the seine bs, H. M., Respiration of wounded plants. Annals of Botany 10: 1896; . i]. 202 BOTANICAL GAZETTE [SEPTEMBER amount of heat liberated by a given organism or part. Because of the roughness of these preliminary experiments, and of my lack of the apparatus for carrying on the experiments under constant conditions, I have made as yet no effort to ascertain the number of calories liberated by a given weight of germinating peas. I hope to do this presently, not only for peas, but also for other things; but I do not wish this statement to be taken as suggesting that I wish to keep this method at present for my own use. Dewar flasks seem to me to offer to the physiologist, both animal and plant, a convenient means of testing the yield of heat by respita- tion, testing in the case of an animal the calorific value of its food, testing in plants and plant parts the liberation of heat at various stages and under various conditions. Since the Dewar glassware & obtainable in various forms, and can be made in others if desired, it can be used for all the purposes of BONNIER’S experiments and for many others. For example, I see no reason why it would not be possible to ascertain the respiratory curve of any particular plant, from the beginning of the germination of its seeds until it had attained considerable size; to ascertain more exactly than we now know the relation of respiratory activity to the other activities or to the stages of development of the plant. These flasks, or cylinders, can be also for demonstration experiments, on the lecture-table for pa proving at once to a class that respiration is really a process 1M vd energy is released, and that it is the chief process by which the living organism obtains the energy which it constantly needs and uses- STANFORD UNIVERSITY California THE SEEDLING OF CERATOZAMIA CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY I15 HELEN A. DORETY (WITH TWO FIGURES AND PLATES XII-XVI) The vascular anatomy of adult cycad stems is likely to be obscured by two sets of complications. One, called anomalous thickening, described by Von Mont (14) in 1832 in species of Encephalartos, is limited to certain forms; the other, the phenomenon of girdling, was described by KARSTEN (5) in Zamia muricata Willd. in 1856, and by Merrentus (8) in Cycas, Encephalartos, and Dioon in 1860. Since then it has been found in the three other genera investigated. In the seedling these complications are either absent altogether or are just being initiated, hence the selection of juvenile forms is proba- ly even more important in the anatomical study of cycads than in that of any of the other vascular plants. Anatomists have recognized this and have given us numerous descriptions, only the more pertinent of which need be cited here. In 1856 Karsten (5), in the work mentioned above, found that each of the cotyledons of Zamia receives only one bundle, which may branch ; that the central cylinder is broken up by parenchymatous communication between pith and cortex; and that in older stems, with the increase in the number of cauline strands, there is a corre- sponding increase in the number of bundles entering the leaves, because every bundle of the central cylinder contributes a trace. € also observed the frequent anastomosing of the leaf traces reported by Von Moat, as well as the occurrence of girdling. , In 1884 BowEr (1) wrote a few descriptive notes on the seedling of Cycas Seemanni Al. Braun, He found the two cotyledons unequal Mm size and dissimilar in vascular anatomy. He says that while in Some there is a median bundle which extends the whole length of the cotyledon without branching, in others there are two equal bundles Rear the center. In 1887 Greco (4) reported anomalous thickenings in the root of this species, 203] [Botanical Gazette, vol. 46 204 BOTANICAL GAZETTE [SEPTEMBER In 1896 WorspELL (16) discovered them in the adult stem of Macrozamia Fraseri Miq., giving it an appearance which recalled to his mind the stem of the Medullosae. In 1897 the same author (17) gave the name “transfusion tissue” to certain short, scattered tracheids with reticulate markings on their transverse walls, found in lateral communication with the bundles in the green parts of some gymnosperms. He considers this tissue a “direct derivative of the centripetal xylem” in the vascular bundles of fossils. Later in the same year (18) he recorded its occurrence in the cotyledons of Cycas revoluta Thunb. and in the leaf traces of Stangeria paradoxa T. Moore. He found that in each of the two cotyledons of Cycas revoluta, there are three collateral bundles, which may increase to five; that there may be some cel trifugal wood near the base of the cotyledon, but none farther out; that the root may be tetrarch or triarch; that girdling had not yet begun in the young seedling he was investigating; and that anomalous thickenings were conspicuous. In Stangeria paradoxa, the two coty- ledons have a common stalk, each is multifascicular, and the bundles are said to be concentric near the base. The root is triarch, changing to diarch near the tip. In the same paper, the two cotyledons of Macrozamia spiralis Miq. are said to be like those of Cycas revoluta. The author calls attention to the absence of anomalous thicken: ings in this species of Macrozamia in contrast with the mature a of M. Fraseri previously studied by him. In all three seedlings WorsDELL missed the transition from stem to root. In 1898 the seedling of Bowenia spectabilis Hook. was described by PEarson (9). He says that each of the two cotyledons has four to seven bundles derived from one, and that these bundles are all collateral with normal orientation. He is emphatic as to the collateral nature of the bundles, even after having examined a preparation Worspett’s in which the latter considered them concentric: the leaves the bundles are oriented normally, and the centripetal wood, scanty at the base, becomes more and more abundant f se up the petiole; but the centrifugal wood does not disappeat eee the pinnae. The root is tetrach or pentarch, but may reduce to triarch In the young material at his disposal, PEARSON found no anom thickenings in the root, but they were discovered later in prest 1908] DORET Y—CERATOZAMIA 205 older plants by WorsDELL (19), who seized the occasion to emphasize the similarity to the Medullosae. In 1904 Marre (6) published his masterly thesis, which in the third part treats of the seedlings of Dioon edule Lindl., Cycas sia- mensis Miq., and Encephalartos Barteri Carruth. Of his two seedlings of Dioon edule one proved abnormal, one cotyledon being partly aborted. The cotyledonary bundles are mesarch near.the base, but the protoxylem moves quickly outward, so that the bundles are exarch throughout most of their course. The axis is considered as an aggre- gation of leaf bases, and the girdling is explained as being due to intense intercalary growth produced under the influence of the developing leaf within. The four root poles are inserted upon the cotyledonary bundles, the median bundles furnishing insertion for two diagonally opposite poles, and each lateral trace uniting with its mate of the other cotyledon to furnish insertion for the other two poles. Mucilage canals are reported in the root, for the first time in acycad. The root of Cycas siamensis is diarch; its two poles are inserted upon the median bundles of the cotyledons, the lateral bundles dying out in the cortex. Anomalous thickenings or cortical vascular strands are conspicuous; Marre’s demonstration that these are not abnormal, but merely remnants of an ancestral charac- oa justifies his objection to the term “anomalous” used to describe them, In Encephalartos the root is pentarch, and the cotyledonary bundles—a single, ringlike trace from each of the three cotyledons— use with the leaf traces at different levels before entering the central cylinder. This cylinder is polystelic, as in Medullosa anglica Scott. In considering this feature, Matre indorses WoRSDELL’s view that it helps to relate the Cycadales to ancient forms like Medullosa tather than to monostelic forms like Heterangium as Scot suggests. He regards the root of cycads as a “new organ” inserted upon the — extremity of the hypocotyl, and not merely an extension of that Tgan, The main facts discovered by these investigations, and agreeing, - far as they relate to Dioon edule, Cycas, and Zamia, with — lished Studies made in this laboratory by LAND, THIESSEN, = May be classified as follows: 206 BOTANICAL GAZETTE [SEPTEMBER Characteristic jeatures—Under this heading may be placed the occurrence of two cotyledons, the hypogean character of germination, the thick tap root, centripetal wood in the cotyledons and leaves, girdling, and numerous mucilage ducts. Character upon which the seedlings may be divided into two groups.—This is the presence or absence of anomalous thickenings or cortical vascular strands. They occur in Cycas, Bowenia, and Encephalartos; they are said to be absent in Zamia, Dioon, Macro- zamia, and Ceratozamia, though they were found in the mature stem of Macrozamia Fraseri by WorspEtt. Microcycas remains to be reported upon. Features peculiar to certain genera.—We may place here the single cotyledon reported for Ceratozamia, the three cotyledons of En- cephalartos, concentric bundles in the base of the cotyledon of Stan- geria, the polystele in the earliest formed part of the axis of Enceph- alartos, and mucilage ducts in the root of Dioon, The present series of studies aims in the first part to add to the list a detailed account of Ceratozamia, Microcycas, Dioon spinulosum, and species of Zamia; and in the second part to extend the invest!- gation to the conifers by examining some juveniles of each of the great groups. Podocarpus, Keteleeria, Cunninghamia, P inus edule, P. Banksiana, and a few others, as well as the cycads mentioned, are well under way. Ceratozamia In 1846 BRoNGNIART (2) gave the generic and specific names “i Ceratozamia mexicana, a “new cycad from Mexico.” He desctt the adult forms and the ovulate and staminate strobili. In 187° WarMING (15) reported the monocotyledonous character of ve embryo. In 1872 Van TrecHEM (13) examined four seedlings = found a thick scale enclosed by the sheathing base of the single ihe ledon, and, in turn, enclosing a hairy foliage leaf with one vernation. One of the four seedlings was suspected by him of having the rudiment of a second cotyledon. He describes the root after xylem and phloem have reached their final position, and adie he number and derivation of the cotyledonary strands and early | ‘ traces; but in these respects, no two of the seedlings agree A” of mature stem, examined by Sotms-LAUBACH (12) in 1890, W# 1908] DORETY—CERATOZAMIA 207 found to have a single cylinder, but peduncular strands occurred in the pith, an observation which was corroborated later by WORSDELL (16). In the work previously mentioned (6) MatTE made a careful study of the ovulate cone and the mature leaf, with a few observations on younger leaves. He found terminal teeth on some of the pinnae of the younger plants, and at the bases of the petioles stipules with a bundle in each. He says that the meriphyte of the leaves has a modified Q-shape in cross-section, with an anterior system, and shows that in this as well as in other cycad petioles the so-called fusions of the traces are often only approximations (accolements). | MATERIAL AND METHODS The’seedlings of Ceratozamia and Dioon spinulosum were grown from seeds provided by Professor CHARLES J. CHAMBERLAIN; the Microcycas seedlings were given to me by Professor OTIS W. CaLp- WELL, and later some were grown from seeds secured by Professor os. The Zamia seedlings were furnished by Dr. W. J. G. AND. Having in mind the danger of drawing conclusions from a few specimens, I have used freely the wealth of material at my disposal. The chief part of the investigation was made from material fixed Ps picro-acetic-alcohol, stained with safranin and anilin blue, and cut in serial sections, Figs. 21, 22, and 23 are diagrams of wax models Constructed from serial sections. GENERAL DESCRIPTION OF EMBRYO AND SEEDLING The seeds of Ceratozamia are about 2.5°™ long and 1.5°™ thick, that is, about the same size as those of Dioon edule, and intermediate between Dioon spinulosum on the one hand and Zamia on the other. Like most cycad seeds, they are flattened on two or three sides by the pressure of growth within the cone, and it is not unimportant to remember that during the whole period of embryonal development ~—the longest known for a cycad—the seed lies upon whatever side it happens to fall. The single cotyledon begins to be differentiated = November, and early in December its appearance is like that represented in fig. r. Later it begins to surround the axis (fig. 2); 4nd finally the two edges meet (fig. 3). In these early stages, the coleorhiza is proportionally long; but later elongation of the coty- 208 BOTANICAL GAZETTE [SEPTEMBER ledons forces the base of the embryo backward, so that both coleo- rhiza and suspensor are crushed little by little to a flat, brown disk (figs. 4, 5). Further elongation forces the base of the embryo through the softer, micropylar portion of the seed coat; figs. 6, 7, 8 show this and the two succeeding stages. In jig. 7 the base of the cotyledon is curved downward, and the plumule is seen issuing from between its opened edges; and it may be observed that this method of development has thrown the first leaf out of alignment. The edges close in again, and remain adhering the full length of the coty- ledon (fig. 13). The tip is sometimes lobed (figs. 14, 15). The cotyledon always develops on the lower side of the embryo as the seed lies during germination. In seedlings which were turned after the cotyledon had begun to develop, the plumule has not suc- ceeded after a year in emerging from underneath the cotyledonary sheath with which it is hampered. Fig. 8 shows the appearance of the tardy root, which has made its way through the brown cap formed from the remains of the disorgam- ized coleorhiza and suspensor. When the root pierces the soil, the starch is transferred to it from the endosperm, and the root thickens into a tap root. By its further penetration into the soil, it often draws the upper portion further down, imbedding the seed, and possibly giving to the first series of lateral roots their initial upward slant. The lateral roots almost always appear in threes, whether the root be tetrarch or triarch. Fig. g represents a seedling toward the close of this period of its activity. The extreme shortness of the hypocotyl may.be conjectured from the small distance betwee? the base of the cotyledon and the insertion of the first whorl of lateral roots. The plumule is composed in this case of two brownish, hay scales, enclosing a foliage leaf with circinate vernation (#ig- 7 a Each scale is terminated by a sharp, curved point. The number ¢ scale leaves varies in different seedlings; some have only one, and in in some few observed the first organ was a perfect foliage leaf, base of both scale leaf and foliage leaf is furnished with broad, WS like expansions which enclose the next leaf. The petiole of the first leaves reaches a length of 15~20°™, and bears one or two pairs pinnae inserted near the adaxial face. Between the two erminal : ms pinnae there is a tiny, sharp spine, which has its counterpart 1? 1908] DORET Y—CERATOZAMIA 209 apical point of the scale leaves. At irregular intervals along the petiole are other, even smaller points. The first leaves are opposite, but the later ones assume the spiral phyllotaxy represented in fig. 12. ANATOMY As was above noted, the edges of the cotyledon close in after the exit of the plumule, the two halves of the adaxial face meeting in a plane represented by the line ad in jig. 13. Three bundles enter the cotyledon from the vascular plate, and each dichotomizes again and again (jig. 16), the median one being no more a “double” bundle than any of the others. The number of traces may be increased to fifteen toward the upper portion, but is gradually reduced again toward the tip, some bundles approximating in pairs, others dying out. Those in the lobes disappear lower down than the others (fg. 15). The bundles are collateral throughout the cotyledon, and their orientation is normal, as seen in figs. 13, 14, 15, Where the xylem faces the line ad. The wood is mesarch (fig. 17), with the Protoxylem gradually moving out toward the phloem as it ascends. the upper portion centrifugal elements are wanting, that is the wood is exarch (fig. 18). The vascular system of the cotyledon is differentiated relatively early in the development of the seedling. In that from which fig. 19 was drawn, in which no root has yet appeared, the vessels are fully matured. Worspe.t’s transfusion tissue was frequently observed in direct continuation with the centripetal xylem 8. 18, ir), Mucilage canals are numerous in the lower part, and seem to bear no definite relation to the strands (figs. 30, 31); farther up they usually number one more than the strands and alternate with them; higher still they die out irregularly; in some cotyledons they are absent altogether, The vascular plate of the hypocotyl axis is irregularly four-sided " bikie in cross-section; all the xylem is in the center, sometimes in “solid mass, sometimes interspersed with pith cells. ‘The protoxylem = ints are clearly distinguishable. In the plant from which fg. 20 drawn, the protostelic condition persisted through a vertical mtahce of 1.6™™, Above this the pith cells occupy the central "*8!0n, so that a siphonostele replaces the protostele (fig. 28). About 210 BOTANICAL GAZETTE [SEPTEMBER 1™™ above the upper terminus of the protostele, the xylem is grouped sometimes in four conspicuous mesarch lobes, but oftener in three prominent ones and a fourth weaker one (D, fig. 29). From this weaker lobe a very small strand passes out (D, jigs. 21-24, 26, 30), and in some cases it branches, but is lost in the cortex. From the lobe diametrically opposite, the median strand of the cotyledon (C, figs. 21, 24, 25, 29, 30) enters that organ; and from each of the other two angles or lobes a strand passes out (A, B) and branches, one member in each case bending tangentially (b, 0’) to form the lateral trace of the cotyledon, the other, a very small strand (4, @’), either fusing with the leaf traces or dying out in the cortex. This cotyledonary node is represented in cross-section in the diagram (fig. 24). | Comparison with the same node in Zamia, Cycas, Dioon edule, and Microcycas suggested that the smaller bundles (D, a, a’) were the mates of the larger ones on the side of the cotyledon (C, }, ¥), and that the second cotyledon was suppressed. The cause of the sup- pression was indicated by the long-continued one-sided presentation to gravity during germination, and the fact that the cotyledon 's always on the under side. It was with the intention of testing these surmises that the experimental work already recorded (3) was under- taken. Fig. 25 represents the cotyledonary node in Ceratozami@ embryos developed on the clinostat, and jig. 13a a transverse section of their cotyledons. Although the stem contains several layers of extrafascicular cambium (cb, fig. 32), I have not been able to find in two-year-old plants any anomalous thickenings except the solitary bundle (fig. 33) whose position in the base of the cotyledon is indicated in fig. 3° at z. This bundle has its origin in a small group of cells (c”, hg: er in the outermost layer of cambium. It is about 0.4™™ long ” approximately vertical. Its tracheids have only spiral thickening» The foliar bundles (fb) may occur in four groups alternating the cotyledonary bundles (figs. 21-23, 26, 30); but oftener there as only three groups, because of the fusion of two of them or the a elimin *tion of one, on the side of the suppressed cotyledon, when t main bundle (D) is slight or entirely wanting (jig. 20)- At first they are all vertical; higher up they branch, and a strand from each grouP 1908] DORET Y—CERATOZAMIA 3k is sent to the first leaf (fig. 22). As previously noted, this organ, whether scale leaf or foliage leaf, is displaced laterally by the peculiar- ities of its development. All the ; ©p t i i likewise races which enter it are likewis Nas @), Om : distorted, giving rise to a pseudo- . J \ _4 girdling condition which is appar- ent in very young seedlings (figs. 22,27, 31). Thetwotraces which enter from the groups nearest the leaf (e, e’) take first a radial, and then a tangential course to reach 4 position in the middle of the leaf (figs. 22, 31), showing on the way atendency tobranch. The traces (¢,d’) supplied from the groups farther away take a tangential ~ Course, each giving off vertical branches, which in turn branch again. The remaining traces of the original four foliar bundles ascend vertically (fig. 2 5), and branch and anastomose freely. Only a limited number, in most Cases four or five, remain (jb, jigs. 24, 31). Before reaching the leaf base, each of these divides, one member entering it (¢, jig. 23), the other, which remains small, being directed toward the growing point of the stem (u, figs. 23,27). Fig. 23 Tepresents the branching]and ‘nastomosing of these strands. It should be noted that the vertical ) scale of the three diagrams (figs. Fic. 1.—Study of pO POG *1~23) is magnified considerably. () to apex (?); none oe In the younger stages there;is no attempt at girdlin . oe of the leaf traces, except that which has been referred to in 212 BOTANICAL GAZETTE [SEPTEMBER leaf as pseudo-girdling, whose cause is to be sought in the accident of its development. When the inner face of a leaf. encloses a mass whose diameter is less than 3™™ (fourth leaf in fig. 12), the vascular bundles of that leaf are all vertical; but when the enclosed mass, by its enormous radial growth, has reached a diameter of 5-8™™ and comprises two or more developing leaves (second leaf in fig. 12) the base of the enclosing leaf enlarges its inner face accordingly. The first stage in the enlargement consists in an increase in the number of cells, but the second in a horizontal elongation of these (text jig. 1). While this is going on the older part of the central vascular cylinder is also increasing its diameter, separating farther and farther the original positions of the bundles of the leaf. As a result, the marginal traces gradually elongate as they are drawn more and more from the vertical position, and their upper parts stretch outward in the direction which the leaf takes. These facts have been observed repeatedly; whether they are an adequate solution of the problem of the cause of girdling, as Matte thinks, I am unable to say. In seedlings with three or four leaves, the stem bundles (#, jig. 19) branch repeatedly, and many of the branches reunite to form a sm number of traces. Each of the remaining ones now forks once, the larger member in each instance going to the leaf as before, the smaller one continuing in the axis. Thus, even at this early stage, there 1s present the sympodial stem described by Miss Sarr (12) for older plants. The number of strands entering successive leaves Was seen {0 increase, sometimes with great regularity. In the plant “ee dissection is represented in figs. zz and 12, the number of traces was increased by one in each successive leaf, from the cotyledon with three, to the fourth leaf with seven; but the increment W% not so constant in all the plants observed. Within the leaf base and-in the petiole, the bundles branch and | anastomose freely. There is no real Q in these first leaves; the bundles are arranged simply in an open arch. Text fig. 2 is of a foliage leaf which was the second lateral organ of the io that is, it was preceded by only one scale leaf. The scale leaf a four bundles; this leaf has five (a, 8); but just above the stipules number is reduced to four by the approximation of two of them (0) 1908] DORET Y—CERATOZAMIA 213 Other changes occur as the meriphyte ascends the petiole (c, ne Just below the first pair of pinnae the branching is rapid, and _— level where the blade is seen exteriorly to separate from » — there are four strands provided for it (7). In the rachis —— approximation takes place (2), and the number of bundles is — : two (m). Each enters a pinna and branches continuously (n, ie The growing point terminating the rachis has no vascular ae in this leaf, in this respect agreeing with the young leaf represente = fig. toa. As the plant increases in age, the meristem of this 63 "tains its activity longer, producing a greater number of pinnae, as the seed plants. | i bos a in all the leaf traces is endarch in the central cylinder (fg. 26), but it soon becomes mesarch, with the protoxylem moy- ing outward by almost imperceptible degrees. t never reaches the exarch condition, how- ever; even in the tips of the pinnae there are always two or three elements of centrifugal Wood. Here and there May be seen a few elements of transfusion tissue. Mucilage canals are numerous in the leaf bases (jigs. oe but they have no more definite arrangement ee " ules base of the cotyledon. Throughout the regi ox a ca ae there is a gradual decrease in number, luscine ee rae due to fusing. Toward the upper levels of this region sisal ee times “rranged in two series, an adaxial row and an a About rem With a definite relation to the bundles (ext jig. 20). al (d) above the base, there is left only one in ( at an Which sists for half the length of the petiole (¢). The haces of the leaves as ct as of the cotyledons are persed thick layer of cork. As was seen externally, the hypocotyl is extre Fic. 2.—Cross-section of flattened cells from inner face of petiole near the base. 214 BOTANICAL GAZETTE [SEPTEMBER short, the transition from stem to root taking place in an almost hori- zontal plane (jig. 30). In the absence of cauline bundles, the root poles are inserted upon the cotyledonary strands (A, B, C, D, jigs. 34, 35). There is no rotation of the protoxylem, but the phloem and metaxylem separate opposite the protoxylem groups (Bm, Cn, jig. 36), the cambium proliferating to fill the breach in the metaxylem, and the cortex invading the space left vacant -by the phloem, The resulting halves swing, the one to the right, the other to the left, giving the appearance of a double fan of phloem and metaxylem connected by a single group of protoxylem. The right half of the phloem of one pole joins the left half of that of the next, and the cambium layer is thus curved inward (cb, figs. 37, 38). One result of this compli- cated process is that the entire xylem system of the root is bordered peripherally by cambium. The medulla throughout the root is extremely meristematic, and its activity sometimes results in a displacement of one or more of the protoxylem groups, giving an unsymmetrical appearance in cross- section, This activity is indicated by the thin walls (0, fig. 3%) showing recent division. a In all the plants I have investigated, the number of poles remains constant throughout any given root. This number may be three or four, depending seemingly upon the degree of development attained by the median bundle of the aborted cotyledon. Figs. 26 and 34 will serve to illustrate this point. They represent the same level in two different plants. In the former the median bundle (D) bis very weak, and there were but three root poles; in the latter this bundle was well developed and the root was tetrarch. Fig. 39 represents the condition of the root tip in the re the differentiation of protoxylem. The connective tissue is cle: y defined, but there is no xylem plate connecting the poles. ere tion of longitudinal sections of the root tip furnishes nothing that co be added to the description of RemnKe (ro). One initial group P*™ duces plerome, another periblem. There is no calyptroge? - = matogen, but the outermost layers of the periblem become Joosent at the tip and form the root cap (k, fig. 42). : ak There is no distinct endodermis, and the pericycle 1 ae layered, making it impossible to distinguish with absolute ion of 1908] DORET Y—CERATOZAMIA 215 tainty any line of demarkation between phloeoterma and stelar tissue. There are no anomalous thickenings in the roots of plants two years old. In general, mucilage ducts extend but a slight distance into the Toot, usually about 8™™, but in one specimen they were beginning to be formed in the plerome, immediately behind the region of its differ- entiation (md, fig. 42). The lateral roots are diarch. Fig. 40 represents a transverse sec- tion of a secondary root and the exit of a tertiary one. The upper- most lateral roots become ageotropic at a very early stage, and show symptoms of bacterial infection; and in some of the two-year-old plants, these roots present the characteristic ‘“‘coralloid” appearance indicative of algal infection. € root, as was seen above, is late in developing. Fig. 27 represents the position and form of the meristematic plate, which has given rise to stem above, but is yet inactive below. Fig. 19 shows the beginning of the activity which produces the root; the central portion of the active region in this figure is sketched in greater detail in fig. 41. In the stage represented in fig. 42, the root cap is devel- oped and the plerome and periblem initial groups are easily distin- guishable, but the plerome has not yet differentiated any xylem elements, While in older seedlings the vascular systems of stem and root seem 'o be continuous, one sometimes finds sections which indicate a certain amount of interruption. Such a case is shown in fig. 43.’ Discussion The result of the experimental work on Ceratozamia places this 8enus in line with the other cycads with reference to the dicotyledonous * When this investigation was completed, MATTE (7) published a preliminary note on the same subject. He says that the petiolary bundles have the @ arrange- ment, that there is an anterior fascicular system in the region, of insertion of the rachis, _ that the pinna has terminal teeth. These features do not appear in any of my Speaking of the root, he says it is tetrarch, and that he has observed a Progressive reduction of poles, to three and even to two. As I have observed, no tria “tion occurred in the roots of any of the seedlings I sectioned, and the root 1s 4 th as often as it is tetrarch. He has also found the abnormal thickenings strongly ped; but he does not give the age of the seedlings which manifest them. 216 BOTANICAL GAZETTE [SEPTEMBER - character. The proof of the abortion of the second cotyledon and the discovery of the manner in which that abortion was brought about naturally revive the question of the monocotyledonous ‘nature of certain dicotyledons. It is possible that in some cases this condition may be caused by the same factor which produces it in the embryo of Ceratozamia, but this is not so in all cases; the experimental work now in progress upon these forms shows that other factors are involved. The lobing at the tip of the cotyledon is suggestive of a primitive condition, which will be discussed in connection with Dioon spint- losum. It would be interesting to compare the cotyledonary node in all cycads, in order to determine whether they are modifications of the same type or whether there are different types; but it is a matter of regret that all investigators have not considered it of sufficient impor- tance. Marre has described it fully for Dioon edule and Cyeas siamensis. The latter is clearly a modification of the type Which may be represented by the former. The present paper shows that Cerato- zamia conforms to this type, and it may be in place here to say that Microcycas and the species of Zamia I am investigating are the same. WorsDELL’s Cycas revoluta and Macrozamia spiralis are doubtless similar. Encephalartos Barteri according to MATIE's description, Zamia muricata according to KarsTEN’s, and Bowen spectabilis according to PEARSON’s seem to differ from this tyP® in receiving only one bundle from the central cylinder; but there are two facts which conspire to make us consider that the of Encephalartos described by Marre was an unusual one: the presence of three cotyledons, and the union of the cotyledonary strands with the central cylinder at different levels. ie That cycads, especially such fernlike ones as Stangeri@ Bowenia, should be found to have an occasional concentric bun is only to be expected from the nature of their fern origin. hie: DELL’s announcement, then, of such bundles in the base of the oy: ledon of Stangeria was not a surprise, even though his are were not convincing. But the emphatic statement of PEARSON of he could not be convinced of it in WorsDELL’s preparation : Bowenia raises the doubt whether he would have recognized it 1p ae 1908] DORET Y—CERATOZAMIA 217 geria. Of course the whole question resolves itself into the possibility of determining phloem in the absence of sieve plates. In the feature of anomalous thickenings, as in so many other features, Ceratozamia appears to hold an intermediate position. The extrafascicular cambium is clear and distinct, yet in plants with two scale leaves, two expanded foliage leaves, and two or three leaves developing, the secondary fascicular systems are entirely wanting. The failure or delay of this cambium to function indicates that it is a vestigial character. I have seen it in Zamia as clear and distinct, though not so abundant, as in Ceratozamia. There seems to be great variation in the number of root poles throughout the whole group of cycads and even in individual roots. his variation, taken in conjunction with the fact that in Ceratozamia the number depends upon the degree of development of the median bundle of the aborted cotyledon, indicates that this character is not to be depended upon as a phylogenetic one. Summary I. Ceratozamia is dicotyledonous, the second cotyledon being aborted by gravity. 2. The cotyledon is often lobed at the tip. It is multifascicular, and all the bundles are derived from three. The wood is mesarch at the base and exarch in the upper portion. Mucilage ducts usually alternate with the bundles. _ 3. The leaf traces are at first vertical; girdling follows upon Mcrease in radial growth of the enclosed leaves and stem apex. The wood of the leaf traces is endarch in the central cylinder, but becomes mesarch in the leaf base and remains so to the tips of the pinnae. 4. The scale leaves are aborted foliage leaves. 5. The first-formed portion of the central vascular cylinder may bea protostele. 6. The stem is a sympodium. 7- There are several layers of extrafascicular cambium, but _ Seedlings two years old only the slightest trace of anomalous thick- ening, 8. The root is a delayed organ, and its four poles are inserted "pon the cotyledonary bundles. 218 BOTANICAL GAZETTE [SEPTEMBER g. The entire xylem system of the root is bordered peripherally by cambium. Grateful acknowledgments are due to Professor JoHN M., Covut- TER and Dr. W. J. G. LANp, under whose direction the investigation was conducted, and to Professor CHARLES J. CHAMBERLAIN for abundance of material. THE UNIVERSITY OF CHICAGO LITERATURE CITED 1. Bower, F. O., On the comparative morphology of the leaf in vascular cryp togams and gymnosperms. Phil. Trans. Roy. Soc. 1'75:583. 1884. - Bronentart, A., Note un nouveau genre de Cycadées du Mexique. Ann. Sci. Nat. Bot. TIL. 5:5. 3- Dorery, HELEN A., ie tics of Ceratozamia: a physiological study. Bot. GAZETTE 452412. 1908. Grecc, W. H., Anomalous thickening in the roots of Cycas Seemannt Al. Braun. Avninls of Botany 1:63. 1 - Karsten, H., Organographische Retrachtunpen der Zamia muricata Willd. Abh. der Betlig Akad. 193. 1856. 6. Marre, Henri, Recherches sur l’appareil libéro-ligneux des Cycadacées. Caen. 1904. , Note préliminaire sur des germinations de Cycadacées. Rennes. N > un 1907. 8. Merrentus, G., Beitrige zur Anatomie der Cycadeen. Abh. Konigl. Sachs. Gesells. Wiss. '7:565. 1860 9. Pearson, H. W., Anatomy of the seedling of Bowenia spectabilis. Annals of Botany 12:475. 1898. 10. REINEE, J., Beitrage zur Kenntniss der Gymnospermen Wurzel. Morph. Abh. Leipz. 1873. (Reviewed in Just’s Bot. Jahrb. 1:205. 1873 ) a Ir. SmirH, Frances GRAcE, Morphology of the trunk and develope 0 microsporangits of cycads. Bot, GAZETTE 43:187. 1907- der 12. Sotms-Laupacu, H. Grar zu, ee phone der Stangeria und iibrigen Cycadeen. Bot. Zeit. 48:17 13. VAN TiEGHEM, Pu., Symetrie de ar des plantes. Ann. Sci. V. 13:204. 1873. 14. Von Mout, H., Ueber den Bau der Cycadeen Stammes und sein nee zu dem Stammes der Coniferen und Baumfarnen. Abh. Konigl. Miinch, 1832. Vermischte Schriften 195. 1845. ? der Warne, E., Ein Paar nachtrigliche Notizen iiber die Entwickeluns Cycadeen. Bot. Zeit. 36:737. 1878. with - WorspDELL, W. C., The anatomy of the stem of Macrozamia com mpared that of the other genera of Cycadeae. Annals of Botany 10:601- ”“ Nat. Bot. m4 sy al an 1908] DORET Y—CERATOZAMIA 219 , On the origin of transfusion tissue in the leaves of gymnospermous plants. Jour. Linn. Soc. 33:118. 1897. , Comparative anatomy of the Cycadaceae. Jour. Linn. Soc. 33:437- 17. 18. 1898. 19. , The anatomical structure of Bowenia spectabilis Hook. Annals of Botany 14:159. 1900. EXPLANATION OF PLATES XII-XVI All the drawings except figs. 6-11, 16, 21-25 were made with the aid of a camera lucida. The abbreviations used are as follows: A, B, C, D, the four main cotyledonary bundles; An, Bn, Cn, Dn, the corresponding root poles; C, median bundle of developed cotyledon; D, median bundle of aborted one; 4, a’, lateral bundles of aborted cotyledon; 6, ¥, lateral bundles of developed one; ad, adaxial face of cotyledon; c, cotyledon; cb, cambium; ob’, cb”, extra- fascicular cambium; cl, coleorhiza; ct, connective tissue of root; ¢x, cortex; ofx, centrifugal xylem; cpw, centripetal xylem; d, d’, lateral traces of first leaf; ¢, ¢, middle traces of same; /f, foliar bundles; /*, /%, f%,/% four principal groups of foliar bundles; g, cotyledonary trace; h, vascular system of hypocotyl; 7, vas- cular system of root; imd, initiation of mucilage duct; 4, sclerenchyma; ky root cap; J, leaf; m, meristematic plate; md, mucilage duct; », medulla; 9, indices of radial cell division in medulla; /, plumule; ph, phloem; ph, protophloem; Px, protoxylem; px’, rupture of tissues caused by protoxylem; 4, plerome; 7, root; » Suspensor; #, leaf trace; ér, transfusion tissue; ™, stem bundles; v, periblem; ©, stipules; x, xylem; y, cork; z, anomalous thickening. Fics. 1-3.—Stages in intraseminal development showing single lateral cotyledon and gradual enlargement of its base to encompass axis. 5. Fic. 6.—Rupture of micropylar end of seed coat and protrusion of base of x4 embryo. i Fic. 7.—Bending of base of embryo and exit of plumule. xX}. Fic. 8.—A of root. X#. Fics. 9, 10.—Young seedlings. Fic. 1oa.—Longitudinal section through tip of unfolding leaf. Fic. 11.—Dissection of aerial portion of two-year-old seedling. Fic, 12,—Diagram showing spiral phyllotaxy of later leaves. Nat. size. Fic. 13.—Transyerse section of cotyledon. 8. : Fic. 13¢.—Transverse section of cotyledons of embryo developed on clinostat. < Nat. size. Fic. 14.—Transverse section of upper portion of cotyledon showing tendency - X8 og 15.—Transverse section of same cotyledon nearer tip. x8. IG. 16.—Diagram to show venation of cotyledon. Fic 17.—Mesarch bundle from lower portion of cotyledon. 380. ss Fic. 18.—Exarch bundle from the middle region of cotyledon. X 380. 220 BOTANICAL GAZETTE [SEPTEMBER . Fic. 19.—Longitudinal section of lower part of embryo emerging from eS Fic. 20.—Transverse section of the vascular plate of hypocotyl. 225. Fic. 21.—Diagram representing rise of cotyledonary bundles from vascular plate. : Fic. 22.—Diagram showing origin and course of first leaf traces. Fic. 23.—Diagram showing origin and behavior of traces of second leaf. Fic. 24.—Horizontal diagram of cotyledonary node. Fic. 25.—Same node in plants developed on clinostat. ae Fic. 26.—Transverse section slightly above cotyledonary node showing the four main cotyledonary bundles and the three groups of foliar bundles. eh Fic. 27.—Longitudinal section of embryo somewhat less developed than one represented in fig. 19. ro. : Fic. 28.—Transverse section of stele of hypocotyl 2™™ above the section represented in fig. 20. 225. ; : IG. 29.—Transverse section of stele of hypocotyl immediately below oy ledonary node. X225. Fic. 30.—Transverse section of plant with median bundle of aborted cotyle don fairly well developed. Same level as jig. 26. X8. ; x8. Fic. 31.—Section of same plant 140 » above that represented in fig. ee tyle Fic. 32.—Detail of portion of axis 0.2™™ below fig. 39, between Be h gave donary bundle B and the phellogen; shows group of cambium cells whic rise to anomalous strand z. Kae ted in base Fic. 33.—Transverse section of the anomalous strand represented | of cotyledon in fig. 30. Xx 35 ns Fic. 34-—Cotyledonary node of plant with median bundle of aborted cotyl don well developed. 150. phloem Fic. 35.—Stele of hypocotyl 0.36™™ below fig. 34; xylem and collected in ring. Xr150. king Fic. 36.—Section of stele of same plant o.16™™ below jig. 353 shows b apart of phloem opposite the protoxylem. x50. «of metaxyiell ‘Fic. 37.—Same, o.2™™ below the previous section; separation 0 7 lateral f Fic. 38.—Section of root stele between the third and fourth whorls 0 roots. X179. -orentiation Fic. 39.—Section of stele near root tip at beginning of diff of xylem. X225. : tertiary Fic. 40.—Transverse section of stele of lateral root showing exit of @ root. X225. “+ forma Fic. 41.—Longitudinal section of seedling showing beginning of root tion. Xro. 3 Fic. 42.—Detail of beginning of root formation. 60. pocoty! a . . hypoe Fic. 43.—Detail showing interruption between vascular tissues of and root. Xr120. DORETY on GERATOZAMIA ree ae PH) , te Gye 04 wy, 2 ry) AST A Dorey dof fe Helen DORETY onGERATOZAMIA BOTANICAL GAZETTE, XLVI PLATE Cie 2e".9 UY . 4 AX Sry € x ts Atl favs 4 .\ ss “ Woereey’ o-—S@ Oe tat: ane SOS HR BESS. WEN mere Smee esa ey, BS Ls 4 thy > CI Be! CO 45 e a. ns a Meer 4 Chit Wh ee i +o an we Oe yo 2a TNA D am oiNee. Ls HH Geese me Mice ‘3 SIAL rt e, C] . oA i) me we % a LTS « LA SELAG = (425 e/: Mh O%, “@ &, a tiny ieee: tp TL Vargiee craial A NNW NY Oy usar \) ING. bi Nise aesy @, q oe. Use e Ors (we peas DORETY on GERATOZAMIA BRIEPER ARTic ee. THE NUMBER AND SIZE OF THE STOMATA For some educational purposes it is needful to know which plants possess the largest, the most numerous, the most readily observable, or the most definitely distributed stomata, and what quantities are involved in each of these features. The most important work upon the subject thus far is by Wetss,t but he includes only a few of those plants used for labora- tory study in this country, namely, the common greenhouse plants and those readily raised in greenhouses from seed. Accordingly, in continuation of similar studies upon other topics as already described in this journal,? I have undertaken to obtain exact data upon this subject, with results recorded below. The study was begun, and carried well along, by Miss Atice T. MiTcHELL, while a senior student in Smith College, but she was unable to bring it into final form. I undertook at first simply to complete her work, but later I found it better, in order that all the results might represent a single method of treatment, to work over the entire subject from the begin- ning. The work has been done in the laboratory of plant physiology in Smith College, and has had the criticism and advice of Professor W. F. GANONG. My method of study, in general, was that developed by Lioyp in his Tecent investigations3 on the stomata of desert plants. I removed pieces of the epidermis from different parts of full-grown representative leaves, and dropped the pieces immediately into absolute alcohol. In order to test the possible effect of any shrinkage of the epidermis upon the numerical results, I made many comparisons of the data yielded by the epidermis alone with those vielded by untreated leaves; but I found no appreciable differ- ences. I used throughout the same microscope and combination (Zeiss, objective DD, ocular 1 with cross hairs as an aid to counting). In counting the stomata, I adopted Wetss’s method of counting all those falling within the field of vision, the area of which is easily calculated and reduced to Square millimeters. For every species I counted the stomata, and calcu- lated the mean, from thirty different fields selected at random from epider- mis taken from three different plants (or, in two cases only, from different * Jahrb. Wiss. Bot. 4:123, 196. 1865-1866. * Bor. Gazetre 40: 302. 1905; 45:50. 1908; 452254. 1908; 46:50. 1908, 3 Ltoyp, F. E., The physiology of stomata. Publ. Carnegie Institution. 1908. 221] [Botanical Gazette, vol. 46 222 BOTANICAL GAZETTE [SEPTEMBER shoots of the same plant), this precaution being observed in order to mini- mize any possible abnormalities of single plants. In order to measure the size of the stomata, which involves the length and breadth of the guard cell apparatus when closed, and the length and breadth of the pore when most widely open, the same general method was used, except that, in order to prevent the closure of the pore through any possible wilting of the leaf, the epidermis was removed while the leaves were still attached to the plants. The pores of the stomata were found as a tule to be widest open at about 10 aA. M., and accordingly the material was taken at that time. The measurements were made with an ocular micrometer, carefully valued by comparison with a stage micrometer. As in the case of the countings, thirty measurements were made upon mate- rial practically taken at random from three plants, and the figures in the table represent the mean of these. Only the linear dimensions of the pore are given in the table, but the area can very easily be determined by treating the opening as an ellipse,+ though it is to be remembered, as BROWN and Escoms have shown,5 that in the passage of gases through stomata, it 1s the linear dimensions, and not the area, which is important. The data of the accompanying table may be summarized as follows. The stomata of our common greenhouse plants occur chiefly upon the under surfaces of the leaves, only about two-fifths (43 per cent.) having any upo? the upper surface, and those almost invariably far less numerous than those upon the under. The most numerous stomata occur (in order of abun- dance) in Abutilon, Ficus repens, Phaseolus vulgaris, Cucurbita Pepo, ant Salvia involucrata. The largest occur (in order of size) in Triticum sali- vum, Tulipa, Avena sativa, Primula sinensis, Chrysanthemum jrutescens, and T’radescantia zebrina. Ina general way, there is an inverse proportion between number and size of stomata. Taking all of the plants collectively, the number of stomata ranges from o through a mean of 121 to 484 per square millimeter, or, in general terms, they average over 100 to the square millimeter. The mean size of the open pores is 17.7X6.7 Bs and peer ; “ ; area is 92 square ». The total pore area for a square millimeter O° ™ therefore, is 11,132 square » (12192), which means that when the pores are open, one-ninetieth (or in round numbers over one-hundredth) of the epidermal surface is open. : Some other points worthy of mention in connection with the practical study of stomata in the laboratory are the following: HengtO 5, Preadith 2 4 Area of an ellipse = xr. 5 Nature 62: 212. 1908} BRIEFER ARTICLES 223 The epidermis may readily be stripped in large pieces from the majority of greenhouse plants, notably from Chrysanthemum frutescens, Cyclamen latijolium, Pelargonium zonale, Helianthus annuus, Tulipa, Vicia Faba, and Tradescantia zebrina. It can be removed, though with difficulty, from some others, such as Abutilon, Cestrum elegans, and Coleus Blumei, while im some, e. g., Ficus elastica and Hedera Helix, it can be removed only by tangential sectioning with a razor. STOMATA-QUANTITIES IN GREENHOUSE PLANTS NUMBER SIZE Minimum, mean, maximum in |“ Tength and breadth in microns Upper surface | Lower surface Upper surface | Lower surface Guard pei Guard me closed | °P€? Abutilon : 6 ps eee re) 198-333-484 fe) Oo |17X15) 6X 3 ies BMPR ces SiS 13-25-39 13—- 23-30 |64X32/\31X 7|70X36/38X 8 rok cia MOCemea. os ° 40- 5 ° o |42X29\21X 8 ee eeeats.......%. ° 92-146-224 ° Oo |34X%25)14X Gi Tysanthemum frutescens| 4-15-35 22— 34- 61 |57X 31/31 X11/58X 31/33 XT Coemmeriienta.... ° 30- 55- 88| 0 © |40X27/25X 8 Cu eres... ° O§-14I-211| 0 o |24XIQ/IOX 5 yt aa oe ee 6-28-68 | 175-269-368 |21X14| 5X 2/20X16) 6X 3 Stig n latifolium,.... . ° 2 aR ° o |45X33|21X 7 ee pulcherrima. ° 76-233-365 ° fo) X19g|11 oa : m esculentum...) 17-45-66 | 127-152-184 |27X20|10X 5|27X21|12X sag ~ curtotea he ee f = Phe he : ° o |40X36)19X 6 teil saa Beever ec: ° 228-282-365 | 0 Oar 17| SK 3 Bei ot... ° 52-I2I-193| 0 o |39X2819X 7 rT peae ee ° 23-158-193 fo) o |29X26\11X “sharia rsttees 52-85-118 156-268 /a3Xar118X B02 ine : mM peruvianu 6 Oo |21X17| 9 Impatiens Sultani..... a ; oie Ss : o |26X18) 9X persicum esculentum 12-8 130-202 |27X20)10X §/33X 23/13 X Pans “hag ey Cer aaa ete 7 hl re Si , ° 28X21 oe 4 onium domesticum.| 3-1 Q— 88 |\47X34\23X 8)45X32/24X 9 Pigeon ltatum... . sec 7 33 48 |40X31/20X 6\45X30/22X 7 Ph cage zonale ..... 8-22-39 | 83-118-171 |37X 26/16 9|37X25 19X12 oe eee... c. 13-40-96 | 184-281-356 |25X14| 8X 3\21X13| 7X Primula obconica Ae ree : ° 47- 70 o |39X34/17X Ricj een ° 22—- 31- 48; o 59X46/30X 9 Salvia inven rete 39-64-96 | 140-176-224 |30X16) 8X 4 sox 16 ge og ~sheteicayg OIE eee -26 oT. 3 20X1 Senecio mikanioides .. |. ; pe rye ° o |30X24/10X 7 Tea ees... ° 66-106-149 o |44X32/23X 10 Thien zebrina..... ° 8— 14- 22 ° ° 55X33 31 X12 arte. ee 22-33-44 8- 14- 26 |79X37/40X 7/84X35/38X 7 eee Majus Cipire gta 3 92-130-171 ° o. [27% 12X icia Fae” Se ae 22-40-57 | 35- 47- 66 |56X3 te Nee ous Vie; ee eee — 52- 70 |44X 27/19 gt ene equina.... ||” 17-34-52 aoe 48- 61 \42X26|18X 8\43X 28/19 X “En 52- 68- 88 |47X36\19X 4/45 X 36/19 X Lac... lee 224 BOTANICAL GAZETTE [SEPTEMBER Counting or measuring the stomata im situ on the leaf is possible with a few plants, notably Begonia coccinea, Chrysanthemum frutescens, Fuchsia speciosa, Impatiens Sultani, Primula obconica, Pelargonium zonale, Trades- cantia zebrina, and Vicia Faba. In some others the condition of the pore can thus be observed, though the outlines of the guard cells are not clear: this is true in Senecio Petasitis, Helianthus annuus, Cyclamen latijolium, Coleus Blumei, Cestrum elegans, and Phaseolus vulgaris. Marked variations in number and size of stomata occur, not only in different varieties of the same species, but in the same varieties grown under different external conditions. So far as my observation goes, however, the variation is greater in number than in size. Furthermore, while in most leaves the stomata are fairly evenly distributed over the surfaces containing them, in some, especially in oblong leaves (€. g-, Fuchsia speciosa, Helianthus annuus, and Impatiens Sultani), the stomata are much more numerous near the base than near the tip (more than twice as many), and near the midrib than near the margin. For this reason very different figures might be given for the same leaf by different observers. The opening and closing of the stomata of greenhouse plants is corre- lated closely with the time of day, and secondarily with the weather. already noted, they are, as a rule, as wide open as they can be about 104 “et —this, of course, in well-watered plants. In favorable weather they remain wide open until about 2.30 Pp. M., when they begin to close, and they are mostly completely closed by 5 Pp. M., though some may remain open until 6. On hot days in the spring they may close as early as 12 M., probably because of incipient wilting of the leaf. If the stomata are closed by wilting, they may be made to open, partially at least, by immersion of leaf in water. - The best plants for general laboratory study, taking account of eo removing the epidermis, size and clearness of KRAEMER, Henry, A text-book of botany and pharmacognosy. pp- vi+84o. Ps. Sar (igs. 1500). Philadelphia and London: J. B. Lippincott Co. 1907- 232 BOTANICAL GAZETTE [SEPTEMBER The first chapter describes the “principal groups of plants,” in which types are selected to represent the groups. The descriptions are systematic in form, encyclopedic in content, and entirely unrelated. Just what the student is expected to do with this part is not clear. There follow chapters on the “outer morphology of angiosperms” and “the inner morphology of the higher plants.” This old breaking-up of a subject that cannot be broken is artificial in the highest degree. The confusion is increased by referring to the first topic as ‘‘the anatomy or outer structure of the angiosperms;” and to the second as ‘“‘the inner structure or histology of the higher plants.”” This may be what students of pharmacy need, but it is not modern botany. The remaining chapters deal with the professional details of pharmacy; although under Part I, which bears the title “Botany,” there appear chapters on the “classification of angiosperms yielding vegetable drugs,” and “cultiva- tion of medicinal plants.’ Part II is entitled “‘Pharmacognosy”’ and contains chapters on crude drugs, powdered drugs, and foods. Part III is devoted to “reagents and microscopical technique.”—J. M. C NOTES FOR STUDENTS Synapsis.—GRE£GorrE has published3 an interpretation of synapsis opposing HERtTwIc’s new theory and confirming his own earlier view. He states that the nucleus in synapsis passes through three principal states (/eptoténes, pachyténes, strepsiténes), and that synapsis represents a primary state of heterotypic prophase He says that cytologists diverge into two schools: one believing that the pre-reduc- tion of ch in the zyg stage, the bivalent chromosomes in the strepsinema stage representing the paired true chromosomes in heterotypi¢ mitosis; the other believing that the pre-reduction is effected by a folding back, in the strepsinema stage, of a chromosome which is believed to be composed of two somatic chromosomes attached end to end. However, they all agree in con interpretation of synapsis, deduced from his theory of nucleoplasmic genes The gist of the theory is this: increase of protoplasm cannot continue witho proceed equally, the former generally being ahead of the latter; so the nue plasmic quotient (K/P) tends to diminish. Hrrrwic designates the a equilibrium as “‘nucleoplasmic tension.” This tension causes a sudden at considerable increase of the nucleus, which results in the increase of ghee The increase of protoplasm and consequent increase of chromatin can be — ee back to equilibrium only by nuclear division. Applying the theory to the 0 division in tetradogeneses (sporogenesis, spermatogenesis, and ovogenesis ), . ésentent-ils une 3 Grécorre, Victor, Les phénoménes de I’étape synaptique rep ihe caryocinése avortée? La Cellule 25:87-99. 1908. 1908] CURRENT LITERATURE 233 found an objection, especially where a considerable increase of the ovocyte is not followed directly by nuclear division. For the sake of harmonizing the theory with the phenomena, he suggested that synapsis is really an abortive division. This theory of synapsis naturally tends to interpret synapsis not as a stage preparing for the heterotypic chromosomes, but only as an abortive form of nuclear division. The work of Poporr on ovogenesis of Paludina is the material on which the theory is based. Poporr apparently considers the bivalent chromo- somes after synapsis and before the growth period in ovogenesis of Paludina as tetrads. These chromosomes completely disorganize in the diplonema stage, and the heterotypic chromosomes which appear after the growth period are a new formation, without any connection with the chromosomes that emerged from synapsis. Moreover, WasstLerrr considers that in spermatogenesis of Blatta there occurs a pulverization of chromosomes during synapsis, and he believes that it is a trace of abortive nuclear division. G TRE remarks, under the headings spermatogenesis, sporogenesis, and Svogenesis, that such an interpretation cannot be in harmony with the vast major- ity of cases of synapsis, which are believed to be an important stage in the prepa- ration of heterotypic chromosomes. In conclusion, he emphasizes synapsis as a fundamental stage, which constitutes a primary state of heterotypic prophase and not as an abortive kinesis.—Suicéo YAMANOUCHI. Soil fertility-—The Bureau of Soils is doing an excellent work in seeking the explanation of the differences in productiveness of soils along the lines of a rational Physiology - In spite of various attacks upon the principles which they are devel- oping, the work commends itself to the unprejudiced as consonant with the modern Phases of physics and physiology. Two recent bulletins contain valuable reports of research. Cameron and GALLAGHER have shown‘ that when water has been added to a given soil in such proportion that it is in its most favorable condition for working and for plant development (as determined by expert gardeners), this 1s also the condition when to a pointed inst t it is physically most penetrable This “optimum” water content varies with different soils from 4 per cent. (sandy) 0 120 per cent, (muck). The apparent specific gravity or volume, the rate of ‘vaporation, and some other physical features are also definitely related to the moisture content, changing in a marked way as the optimum water content es - It is also shown that the optimum moisture does not vary with the Plant, but what is best for one plant is best for another in a given soil. Probably the Penetrability of the soil is the important factor, since roots are thus able to Teach their maximum development, and so to offer the largest possible surface me the admission of water. __Another bulletin, by GarDNeER,’ reports a vast number of aa on .. “CAMERON, F. K., and , F. E., Moisture content and physical con- dition of soils. “U. g., Dept. a of Soils, Bull. 50. pp. 70 figs. 33- Jan- FY 31, 1908, *Garpner, F. D., Fertility of soils as affected by manures. Idem, Bull. 48. PP 59. figs. 5+ March 2x, 1908. 224 BOTANICAL GAZETTE [SEPTEMBER the effects of various fertilizers, including stable and green manures, upon wheat seedlings grown in pots. These were checked by field experiments, the results being mainly concordant. Here is presented the largest number of experiments yet made under uniform conditions, and while the conditions are still too complex for full analysis, the trend of the results is clear. Though in certain cases the ‘composition of the soil as modified by the fertilizer is an important factor, it is rarely so important as the physical change. In very many cases, indeed, the crop yield can be as greatly increased by proper manipulation of the soil as by adding any sort of fertilizer. The experiments also indicate that the fertilizing of a particular field or region is a local problem, since even the same soil “types” from different localities show different results with the same fertilizer. (This may also be taken to indicate that the basis of classification of soils used by the Bureau is unnatural.) Everyone who is interested in the growth of plants, either theoretically or practically, should read and reflect on these bulletins.—C. R. B. Reduction and fertilization in Polytrichum.—The mosses have received practically no attention from cytologists. The small nuclei and some diffi- culties in technique are doubtless responsible for this neglect. A paper by the Drs. VAN LEEUWEN-REIJNVAAN® presents the results of an extended investigation of Polytrichum piliferum, P. juniperinum, P. formosum, and P. commune. In spermatogenous tissue the nucleus contains a large deeply staining mass from which the chromosomes arise. From this mass there is cut off a small body which passes out of the nucleus into the cytoplasm and divides to form two cen: trosomes, These behave like typical centrosomes, and in the telophase are a cluded within the nuclear membrane. At the last mitosis they remain In the cytoplasm and become blepharoplasts. At the same time a large piece oy matin, which may be called a Nebenkern, is cut off and cast out into the cyto- plasm, where it gradually degenerates. In the sporogonium the mitoses show 12 chromosomes, 4 long, 4 short, and 4 medium. In the gametophyte there are 6 chromosomes, of which 2 ar¢ long, 2 short, and 2 medium. At the last spermatogenous division the 6 chromosomes unite in pairs, fusing longitudinally, so that one counts 3 chromosomes. nae the sperm contains 3 chromosomes, one long, one short, and one medium. the division of the central cell of the archegonium, the ventral canal cell geet cell each contain 3 chromosomes, one long, one short, and one medium. ertilized two cells fuse with each other, and the egg, formed in this manner, is fi by two sperms. The fertilized egg contains 12 chromosomes, 3 from th proper, 3 from the ventral canal cell, and 3 from each of the two sper™s: 6 Van LEEUWEN-REIJNVAAN, J. and W., Ueber eine zweifache ae . der Bildung der Geschlechtszellen und darauf folgende Befruchtung mittels . permatozoiden und iiber die Individualitat der Chromosomen bei einigen Polyt™ arten. Recueil Trav. Bot. Neerl. 4:(pp. 44. pls. 2). 1907- 1908] CURRENT LITERATURE 235 writers believe that this behavior of the chromatin in Polytrichum supports the theory of the individuality of the chromosomes. Commenting upon the above results from the standpoint of one not personally familiar with mitotic figures in mosses, abundant confirmation is needed before the account as a whole can be accepted. We are inclined to believe that the observations are largely correct and that the situation is extremely interesting, but that the final interpretation will not be so widely divergent from curren notions of reduction and fertilization as the one proposed.—CHARLEs J. CHAM- BERLAIN. Ginkgo.—Under the broad title Ginkgo biloba SpRECHER’ gives a rather full account of the genus, arranged according to the following outline: embryo, young plant, leaf, secondary structure, flowers, pollen and fertilization, geograph- ical distribution, uses and culture, fossils, and conclusions. Instead of giving a historical résumé followed by his own investigations, he has simply followed the above outline, using the available accounts and illustrations, and then filling in the gaps from his own investigations. With so large a subject and so many 8aps to fill, an exhaustive investigation of any particular feature could hardly be expected. Most of the original work deals with floral development, leaf development, and anatomy. While the author has studied the gametophyte, it is in this field that he is most indebted to previous investigators. A large number of abnormalities in ovules, stamens, and sporophylls are recorded. Of course there must be a guess at the phylogeny. While the sperms and certain characters of the ovules resemble those of cycads, in most respects Gingko 1s nearer the Taxaceae. Both Ginkgo and the Taxaceae have come from a Filicales stock which has given rise to the Cycadophytes and also to the Cordai- tales and Ginkgoales, the point of departure being in the neighborhood of the fossil Botryopteridaceae. : The book will be useful for reference. It should be regarded asa compilation, Supplemented by extensive personal observations, rather than as a work in which research is the predominant feature—CHaARLES J. CHAMBERLAIN. : SHaw® has investigated the vascular anatomy of the ovulate strobilus of Ginkgo, chiefly with reference to the morphological nature of the “collar.” From aberrant material, which seems to appear abundantly enough under Japanese cultivation, it has been inferred that this collar is a much reduced megasporophyll. From this current view SHaw dissents, on the basis of testimony obtained from the vascular anatomy. The vascular tissue of the collar is “inverted,” and a 7 SPRECHER, ANDREAS, Le Ginkgo biloba L. pp. 208. figs. 225- Geneve. 1907. : * Suaw, F, J. F., A contribution to the anatomy of Ginkgo biloba, New Phytol. 7°85-92. figs. 16-18. 1908, 236 BOTANICAL GAZETTE [SEPTEMBER Heliotropic tone.—PRINGSHEIM discusses in a long and rather technical paper the influence of illumination upon heliotropic tone.? By heliotropic tone he means that internal condition of responsiveness which determines the position of the car- dinal points of reaction—the liminal and optimal illumination both for positive and negative response, and the indifferent zone. He shows that the reaction time of heliotropic plants diminishes with increasing intensity of light, rapidly at first, then more slowly and finally becomes constant. Beyond this a false optimum (really temporary indifference) is reached, but only in plants grown in the dark. If such plants, however, after being taken from the dark are rotated for a time in a light to which they will later react, the indifference disappears and the reaction, con- trary to the earlier statements, is actually accelerated. This reaction, by a plant attuned to a certain light, is indeed the speediest possible at that intensity. In fact during the first part of the illumination of a plant of low heliotropic tone, the direction of the light is of no significance; for whether rotated or even illumi- | nated from the opposite direction, it reacts just as quickly as though continuously illuminated from one side. e same is true in plants of high tone with stimuli of low intensity. During this first period the plant is merely adjusting its tone to the illumination. This alteration of tone is to be considered as an effect upon the excitable structure itself, produced either by a like or an unlike stimulus. One must distinguish between accommodation or adjustment to a given illumina- tion and Umschaltung which determines whether the reaction is to be positive, negative, or none. This Umschaltung is dependent on the difference between the existing tone and that corresponding to the intensity of the illumination. If bo low- toned plant be brightly lighted it reacts negatively; if weakly, the response 1s Post tive. Ifa high-toned plant is brightly illuminated, it reacts positively; with weak: light, it does not respond at all until the tone has fallen far enough, when 4 positive reaction occurs. The tone in both cases follows the intensity of the illu- mination, but rises more quickly than it falls. All hypotheses which predicate heliotropic tone as a constant are faulty. The phenomena line up with those at ready known in certain other organisms and in the human retina, whence it — ec that they are part of a general physiological law as to light perception Geotropism and heliotropism.—The mutual effect of geotropic and helio- tropic stimulation has been the subject of several papers, notably those by WIES- NER, NoLt, and CzapeK. Von GuTreNBERG, working in PFEFFER’S laboratory, has lately attacked the problem whether or not when they operate simultaneously on parallelotropic organs an alteration of geotropic tone occurs.’? He concludes, contrary to other interpretations, that it does not, finding it possible by choosing ° PRINGSHEIM, Ernst, JR., Einfluss der Beleuchtung auf die heliotropische Stimmung. Beitr. Biol. PA. 9: 263-306. 1907. *° VON GUTTENBERG, H. RITTER VON, Ueber das Zusammenwirken vor pag? pismus und Heliotropismus in parallelotropen Pflanzenteilen. Jahrb. Wee 45:193-231. 1907. : eae So eT 1908) CURRENT LITERATURE 237 an appropriate intensity of light in each case to balance the gravity stimulus without any effect on geotropic sensitiveness itself. Thus in the coleoptile of Avena sativa light of about 55 meter-candles, in the hypocotyls of Brassica Napus, Lepidium sativum, and Agrostemma Githago respectively 525, 666, 1026 m.-c., compensates gravity when each stimulus acts at go°. en equivalent light acts at right angles to gravity (plants vertical, light horizontal) the parallelotropic organs take a resultant position, departing about 45° from the direction of each. On the elimination of the one-sided action of gravity by the clinostat, however, they become parallel to the light rays; but even in the final position of rest they have not lost their sensitiveness to gravity. The geotropic series of reactions is quicker than the heliotropic, when the light is reduced to the compensating point; consequently, when light and gravity act antagonistically, the geotropic curvature a rs first, and the maximum of heliotropic stimulation does not appear until much later. While these results are strictly true only for the plants observed, yet the principle is probably valid for others.—C. R. B. Development of Juniperus.—Two preliminary accounts of fertilization in uniperus were noted in this journal (40:318. 1907). The two accounts differed mainly in regard to time relations, NoREN stating that the interval between pollination and fertilization was over a year, while SLtupsky claimed that the development from megaspore to embryo occupies only a single summer. The Present account‘? shows that Norn was right, SLupsKy having made a mistake in estimating the age of the cones. The pollen grain in the uninucleate condition reaches the nucellus the middle of June and soon divides into a tube cell and Senerative cell, the latter remaining undivided until the following May, when it forms the stalk and body cells. Early in July the body cell gives rise to two equal male cells. In the nucellus there are several sporogenous cells, only one of which divides to form megaspores, the others becoming a nutritive jacket about the functioning megaspore. Usually only three cells of the tetrad are formed. In the archegonium there are four neck cells; and a ventral canal nucleus is formed, but never becomes separated from the egg by a wall. Fertilization occurs about the middle of July and the fusion nucleus passes to the bottom of the egg, where €€ mitoses give rise to eight free nuclei which become arranged in two zones. Walls now appear and the cells of the upper zone divide to form the rosette and Suspensor The account is very full, cytological details of reduction and fertilization being figured and described —Cuartes J. CHAMBERLAIN. Hygroscopic movements of living leaves.—The leaves of some species of Rhododendron exhibit variation movements which follow the recurrence of vezing and thawing weather. The usual position of the leaves is horizontal, With the blade expanded. At freezing temperatures the edges of the leaves curl - : Nog, C. O., Zur Entwickelungsgeschichte des Juniperus communis. Upp- niversitets Arsskrift 1907: 1-64. pls. 4. 238 BOTANICAL GAZETTE [SEPTEMBER under and the petioles allow drooping to occur. With the recurrence of thawing weather the blades expand and the leaf resumes its horizontal position. HANNIG™ has found that the rolling of the leaf is due to a loss of imbibition water by the cell walls, and especially by the walls of the spongy parenchyma. The move- ments may be artificially induced by conditions which cause the cell walls to lose water and so allow a contraction of the walls to occur. The formation of ice, excessive transpiration, etc. are such conditions. The author is inclined to regard this as the first known instance of hygroscopic movements by living leaves. To the reviewer it seems that he has made a closer analysis of the cause of the move- ments, and his discovery consists in showing that while turgor variation is 4 prominent and accompanying feature, the real cause is the fluctuation in the content of imbibition water in the cell walls. It seems likely that many of the leaf movements which have hitherto been regarded as due to turgor changes may later be found to be caused by swelling and shrinkage of the cell walls. The author has not overlooked the fact that some leaves whose structure is apparently as well adapted to such movements as those of Rhododendron do not exhibit them.—Raymonp H. Ponp. Embryo sac of Nymphaea advena.—Miss SEATON’? has examined the em: bryo sac of this species, giving an account of its earlier stages. Abundant material has enabled her to fill in some desirable details. The archesporium is distinguish- able before the integuments begin to develop; and by division of the parietal cell and the epidermal cells the functioning megaspore becomes covered by 4 sterile nucellar cap six to ten cells deep. The sac develops a conspicuous tubular pro- longation into the chalaza, and the fusion nucleus rests in the narrow connection between this chalazal haustorium and the broader micropylar portion of the sac. At the first division of this nucleus there is no wall (contrary to previous observa- tion), and one of the daughter nuclei passes to the end of the chalazal tube. AS before reported for the family, the proembryo is spherical and almost completely invested by endosperm. The monocotyledonous character of Nymphaeaceae * inferred, but no new evidence for it is advanced. ‘This claim, which habitually accompanies the recent studies of Nymphaeaceae, is founded upon certain fi preconceptions as to what constitutes a monocotyledon. It might be wel i investigators of this group to try the effect of their work upon the rigidity a old definitions.—J. M. C. : Araucarians of the Atlantic coastal plain.—BeRRy™ has called ater anew to the wide distribution of araucarians in the Mesozoic, especially * eo trasted ‘with their present very restricted range. A Mesozoic distribution of 12 HANNIG, E., Ueber hygroskopische Bewegungen lebender Blatter bei von Frost und Tauwetter. Ber. Deutsch. Bot. Gesells. 26a: 151-166. 1 gent *3 SEATON, SARA, The development of the embryo sac of Nymphaea Bull. Torr. Bot. Club 35: 283-289. pls. 18, 19. 1908. Jain. Berry, Epwarp W., Some araucarian remains from the Atlantic coastal P Bull. Torr. Bot. Club 35: 249-260. pls. II-16. 1908. 1908] CURRENT LITERATURE 239 group from Greenland to Patagonia in the western hemisphere and from Spitz- bergen to Cape Colony in the eastern is to be contrasted with its present occurrence in South America and the Australasian region. This means that araucarians have disappeared from North America, Europe, Africa, and practically all of Asia. Recent investigations in the Atlantic coastal plain show that the group not merely occurred in that region during the Mesozoic, but was abundant, perhaps the most abundant coniferous type of the older Mesozoic. From this region BERRY escribes three new species: Araucarites Zeilleri, from New Jersey; Araucaria bladenensis, from North Carolina to Alabama; and Araucaria Jeffreyi, from North Carolina.—J. M. C. Embryo sac and embryo of Urticaceae.—MopiLEwsKy's has examined twelve genera of Urticaceae (Urtica, Elatostema, Laportea, Urera, Parietaria, Fleurya, Boehmeria, Dorstenia, Morus, Celtis, Cannabis, and Humulus), and finds that the embryo d embryo are in general of the ordinary dicotyledonous without polar fusion. In Urtica cannabina a conspicuous antipodal haustorium 18 developed, and a much smaller one appears in U. wrens. Many other details are recorded, but they are of no special significance.—J. M. C. Black rot.—The black rot of the grape is the subject of a recent bulletin by REDpIcK and Wuzson,*° which is mainly popular in nature, and is well illustrated and clear. The spores germinate on the vines only in the presence of water. Infection is noticeable after a period of twelve to twenty days, or upon the berry i eight to fourteen days. After discussing the control, it is stated that four acres, well Sprayed, made a gain of 1662 pounds, equalling a saving of $32.95 per acre. It 'S Tecommended that mummied fruit be picked to avoid the spread of the disease, that the ground be turned over as completely as possible, to bury rotted berries, and that the vines be sprayed with Bordeaux mixture, as has been recom- mended heretofore-—F, L. Stevens. Leaves in autumn.—TsweETr summarizes the knowledge regarding the “mptying of leaves in autumn thus.t? It may be considered as settled that the i Benous compounds diminish and are carried back, proteolysis simplifying the proteins to this end; results as to phosphorus compound contradict iy iteeee se Mopitewskxy, JAxkos, Zur Samenentwicklung einigen Urticifloren. Flora 98: 423-470. figs. 7I. 1908. *° REDDICK, Donatp, and Witson, C. S., The black rot of the grape, and its Cornell Univ. Agric. Exp. Sta., Bull. 2532367-388- April 1908. SO inca M., Ueber die Verfirbung und die Entleerung des absterbenden * Ber. Deutsch. Bot. Gesells. 26a:88-93. 1908. 240 BOTANICAL GAZETTE [SEPTEMBER ory, with the weight of evidence in fields of their recovery; the removal of salts needs thorough investigation. As to the autumnal pigments, he reports'® that the yellows are due to a new pigment or group of pigments, which he proposes to call autumnal xanthophyll. He regards it as probably a oe era product of the ‘‘normal xanthophylls, perhaps also of the carotin.” a Torreya in the peiieous—Tivews has described a new species of Torreya (Tumion carolinianum) from the Cretaceous of North Carolina, based on leaf- bearing branches, the leaves showing the distribution and character of the stomata. The genus exists today as isolated species, which are widely separated geographi- cally, and this fact alone would suggest an ancient type. The discovery of inter- mediate stations will bring a knowledge of the time a om distribution and help settle the question of relative antiquity.—J. M Phylogeny of pteridophytes.—Lady IsaBeL BRowNe?° has begun a series of papers intended to bring together the large volume of recent work on the vascular anatomy of pteridophytes, and apply it to a consideration of the phylogeny and interrelationships of the group. This is a very useful service, for it organizes the scattered facts in convenient form, whether one accepts all the inferences or not. In the first two papers, the Sphenophyllales and Equisetales are presented and Lycepodiales begun.—J. M. C. *8 TswETT, M., Ueber das Ayaes des herbstlich vergilbten Laubes. tee Deutsch. Saipie Gieselis 26a:94-101. 19 9 Berry, Epwarp W., A mid-Cretaceous species of Torreya. 25: 88. 1908 Am. Jour. Sci. WNE, ISABEL, The phylogeny and interrelationships of the Peis is A GiGést 4 résumé. New Phytol. 7: 93-113, 150-166. 1908. No. Bayt: A : : | : October 1908 OTANIC COULTER and CHARLES R. BARNES TS da? * vt hy te * 5 - “aes inating Gas an i = e Ly 7 : i a a & 23 NTEN’ ie nd E co + in eastern South Dakota Carnations . JOHN M. tic Alga, hod th ae Edit u A Par, i efer ors: Are there Foliar Gaps in 3 mi i: . : : Effect of Iu Che Botanical Gazette A Monthly Journal Embracing all Departments of Botanical Science Edited by JOHN M. CouLTER and CHARLES R. BARNE ES, with the anesiene of other members of the botanical staff of the University of Chicago. Issued October 17, 1908 Vol. XLVI CONTENTS FOR OCTOBER 1908 No. 4 Brae THERE FOLIAR a a IN ae gah ato Bice ta Jubitet PLATES XVII AND shee Edward C. Jeffrey EFFECT OF tata cae GAS AND ETHYLENE UPON FLOWERING CARNA- TIONS. CONTRIBUTIONS FROM THE HULL menecn@ cant LABORATORY I16 esene FOUR FIGURES). William Crocker and Lee I. Knight 259 FLORAL an Heo rk IN THE PRAIRIE-GRASS FORMATION OF SOUTHEASTERN SOUTH DAKO ee FROM THE ULL BOTANICAL LABORATORY a (with fies pave! LeRoy Wai Harvey - - wa “BRIERE ARTICLES A PARASITIC sae Peeks Sin em react se IN ier odd de AMERICA. George F. Atkin - - 299 Note on B aaceae’ eae Oscar Loew 502 FORMATION OF SO Va Tens nO 7s IN THE eee bshies (wir TWO > FIGURES) O. M. Ball 03 CURRENT LIT. ERATURE : : BOOK REVIEWS 2 $ a fe Bs > a 3 i 2 = a - 305 HE BONN TEXTBOOK. PLANT ANATOMY. BOKORNY’S TEXTBOOK. ( MINOR NOTICES : é e soeigiot siarmuideceaty: «caries ato" ie ae NOTES FOR STUDENTS - re ere “ 2 é rf é é é i 2 gr @ of The Botanical Gazette is Seepage monthly, {The subscription price is $7.00 per year; the price sl Copies is 75 cents. [Postage is prepaid by the publishers on all orders from the Uni ted con " of on 3 Hecmittances should be made payable to The 2 Unavece ‘of Chicago Press, and should be in Chicago or q BF cele” ees postal or express money order. 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It is advisable to a "ditors as to Uhugretions 4 Serpicna | in any article to be offere “Atticles ae if acsivea, may be ordered in advance of publication. “Pwentyve separates a ibs Sa |S printed out yn will be supplied gratis. A table showing appro: cost of additional separate e 2 an order blank which accompanies the proof; a copy w will rhe 6 ei on request August 21, 1896, at the Post- Office at Chicago, as second-class matter, under Act of Congress March 3, 1879. VOLUME XLVI NUMBER 4 DOTANICAL (a OCTOBER 1908 ARE THERE FOLIAR GAPS IN THE LYCOPSIDA ?* EDWARD C. JEFFREY (WITH PLATES XVII AND XVIII) Six years ago the pzesent writer published an account of his studies on the stem of the pteridophytes and gymnosperms.? In the Conclusions not only these large groups were considered, but also the remaining vascular plants, which had been the subject of earlier investigations. The general result was reached “that there are two phylogenetic types of tubular central cylinder, namely, that in which only ramular gaps are present, and that in which both ramular and foliar gaps occur.” Further it’ was stated: ‘‘ The use of these con- stant and characteristic anatomical features results in the division of the Vasculares into two great primitive stocks—the Lycopsida, which = cladosiphonic and palingenetically microphyllous, and the Pterop- sida, which are phyllosiphonic and palingenetically megaphyllous. The Lycopsida include the Lycopodiales and Equisetales. The Pteropsida include the F ilicales, Gymnospermae, and Angiospermae.” he opinion was expressed that the Lycopsida and Pteropsida “appear to have been separate back to the beginning of the period when the paleontological record begins.” Since the publication of that memoir, the writer has been busily engaged in other directions, and his time has been fully taken up. In the interval a great deal of literature has appeared, especially in European countries, on the anatomy and phylogeny of vascular plants, and not unnaturally the emiter’s hypothesis has been subjected to the criticism which is the fate of every scientific hypothesis. The most vigorous objections to : ie from the Phanerogamic Laboratories of Harvard University, * Phil. Trans, Roy. Soc. London B. 195:119-146. 1902. 241 242 BOTANICAL GAZETTE [OCTOBER the hypothesis, as might be expected, have been raised by those whose published views are prejudicially affected by its validity. In spite of all that has been written on the subject, however, the author has seen no reason to modify his standpoint in any essential feature. It is proposed in the present article to deal with some of the objec- tions, mainly resulting from a misapprehension of the author’s state- ments or an unfamiliarity with the anatomical field, which have been raised against the Lycopsida. In a subsequent article the Pteropsida will receive consideration. It will perhaps be well at the beginning to define the Lycopsida and Pteropsida in a comprehensive way and to include external characters as well as anatomical ones. LycopsipA.—Palingenetically microphyllous vascular plants, with ventrisporangiate sporophylls (sporangia adaxial), the tubular central cylinder when present characterized by the entire absence of gaps OF interruptions in the fibrovascular tissue immediately above the out- going leaf-traces——Lycopodiales, Psilotales, Equisetales, Spheno- phyllales. PTEROPSIDA.—Palingenetically megaphyllous vascular plants, with dorsisporangiate sporophylls (sporangia abaxial), the tubular central cylinder when present characterized by foliar gaps or interruptions in the fibrovascular tissues immediately above the outgoing foliar traces.—Filicales, Gymnospermae, Angiospermae. ; It is necessary to define very clearly, on account of numerous mis- conceptions and misunderstandings, the nature of a foliar gap, for the writer’s critics have shown considerable versatility of misunder- standing in regard to this important feature. In one of the more simply organized ferns (Ophioglossum, Osmunda, Schizaea, ea Adiantum, etc.), wherever a leaf passes off from the surface of the stem, it carries with it a fibrovascular strand, the leaf-trace- : foliar trace is derived from the tubular central cylinder of the ste™, and as it bends away from the surface of the stele in its outw er upward course, it causes immediately above it, in the stelar W2" interruption of the fibrovascular tissues, known as the Teaf fi The foliar gap may be distinguished from other gaps in the rr the fibrovascular hollow cylinder by the fact that it ene diately above a leaf-trace. A true foliar gap, moreover, ‘ 1908] JEFF REY—FOLIAR GAPS 243 related to but a single leaf-trace. If several traces appear in relation to a stelar gap, and especially if they are related to the sides of the gap, it may be concluded at once that no true foliar gap is present. It may be added for the benefit of inexperienced anatomists that not all gaps in the wall of the central cylinder are foliar gaps. Where the fibrovascular tissues are much reduced in amount, as is not unfrequently the case, they often break up into a loose meshwork, which has no necessary relation to the vascular supply of the leaves or the branches. LEPIDODENDREAE AND SIGILLARIAE In the memoir cited above, the writer has called attention to the fact that in the Lepidodendreae, which are among the oldest of the Lycopsida, there are no foliar gaps in the tubular central cylinder, when present. Fig. 9 illustrates this feature in Lepidophloios Har- courti. Below in the figure is to be seen the woody cylinder, showing inferiorly some of the thin-walled tissue of the pith. The cylinder is dentate on its outer surface, and the teeth are composed to some extent of small-celled protoxylem. Outside the wood may be seen nests of small cells, which mainly lie in the intervals between the dentations. These are the foliar traces. It is clear that there are nO gaps or interruptions in the central cylinder corresponding to these. Consequently it may be stated that there are no foliar gaps in the species figured. An examination of a considerable number of sections of lepidodendrid stems has made it clear that foliar gaps are absent in the group. In the older Sigillariae the primary wood in the stem ordinarily formed a continuous cylinder, and there were, as in Lepidodendron, nO gaps of any kind except for the outgoing strands of branches. In pea modern Sigillarias, however, the woody cylinder was frequently entirely or partially broken up into separate strands. Sigillaria ‘legans from the Lower Coal Measures had the continuous type of "Woody cylinder, while S. Menardi from the Permian had separate Strands of wood constituting its tubular stele.3 The leaf-traces in both types of Sigillaria stem, however, passed off without leaving any foliar gaps in the central cylinder, for in the Sigillarias of the more ia Stop R. Internal structure of Sigillaria elegans. Trans. Roy. Soc. 41 2533-550. 1905. 244 BOTANICAL GAZETTE [OCTOBER modern type, with the cylinder broken up into numerous bundles, the gaps between the strands were not subtended by the leaf-traces, which took their origin from the face of the fibrovascular bundles. This fact it is very important to keep in mind, in view of the conditions to be found in some of the reduced Lycopsida to be described later. It is further of interest to note that these arboreous lycopods, in which the leaves were sometimes a meter in length, offer no exception in their anatomical structure to the writer’s definition of the Lycopsida. LYCOPODIACEAE Under this heading Lycopodium itself need not be considered, as it has a solid protostelic central cylinder. Phylloglossum, however, has a tubular stele, which in the lower tuberous portion of the stem constitutes in cross-section an almost continuous horseshoe of xylem, without foliar gaps for the relatively large radical leaves (protophylls). The opening in the horseshoe corresponds to the outgoing stran which passes into the resting tuber, forming the next year’s plant. Above the tuber the stem of Phylloglossum passes into the slender peduncle of the cone. In this region of the stem the fibrovascular tissues separate into a number of distinct strands, comparable to those found in the axis of the less ancient Sigillarias. Fig. 8 is 4 Copy of a figure by BERTRAND,‘ showing the manner in which these isolated peduncular strands give rise to the traces of the lower sporophylls of the cone. It will be noted on the lower side of the figure that the bundles are much elongated radially. In such cases they are about to give off sporophyll traces. In the upper part of the figure three outgoing traces are seen, in different degrees of detachment from their ponding ped lar strands. On the left, one of the traces has turned obliquely after leaving the peduncular strand, so that it nearly subtends the hiatus between two peduncular strands. An inattentive observer might readily interpret the hiatus as 4 real foliar gap. Only a consideration of the mode of origin of the trace ai the peduncular strand makes the real condition of affairs apparen' There are clearly no foliar gaps present, else the peduncular $ would fork above the outgoing traces. ‘The conditions in the need part of the stem of Phylloglossum are clearly similar to those obt +Phylloglossum. Archives Bot. du Nord de la France 18853112. #&- 79 1908] JEFFREY—FOLIAR GAPS 245 ing in a Sigillaria with separate fibrovascular strands. In the cone of Phylloglossum individual sections often present an appearance still more misleading. In fig. ro is shown such a condition. A horse- shoe-shaped fibrovascular mass appears in the center, and oppo- site its opening a sporophyll trace. To the right and left below are two other foliar traces. An inexperienced anatomist might readily conclude that the gap opposite the uppermost trace was a true foliar gap. Fig. rz shows a section from another cone, with two such apparent foliar gaps, one on each side, each apparently subtended by its corresponding leaf-trace. Fig. 12 shows another section from the same cone, a small fraction of a millimeter lower down. It is here to be noted that the foliar trace on the right in the preceding figure joins the face of the large cauline fibrovascular strand, forming the same radially elongated mass as is characteristic of the outgoing Sporophyll traces shown in fig. 8 from the peduncle. Still lower down, as was learned from the study of serial sections, the foliar strand on the left joined the outside of its cauline strand in a similar manner. A study of the cone of Phylloglossum has shown that the traces for the sporophylls invariably pass off from the outer surface of the central cylinder without leaving any real foliar gaps. Some- limes two or even three traces may originate along the margins of the same hiatus in the stele. The interruptions in the central cylinder or stele are no more to be regarded as foliar gaps than are the corresponding ones in certain Sigillarias. It is obviously impos- sible with any clear eye to anatomical relations to regard the perfo- rations which exist in the upper part of the fibrovascular system of the stem in Phylloglossum as being of the nature of foliar gaps. Miss SYKEs has recently reached the conclusion that the living Lyco- Podiaceae originated in all probability by reduction from the more complex arboreous lycopods of the Paleozoic period.s Without pre- suming to indorse this view, it may be pointed out that it stands in way of presumably reduced modern lycopodineous forms in any “ase possessing the foliar gaps which were denied to their sup- ea Paleozoic ancestors, which possessed very much larger Ves, er of the sporangium-bearing organs in the Lycopodiaceae. New logist 7241-60, 1908, : 246 BOTANICAL GAZETTE [OCTOBER PSILOTACEAE Fig. 6 shows a magnified view of the stem of T’mesipteris tannensis, as viewed in transverse section. On the lower left side is a blunt projection from the surface of the stem, the base of a sporophyll.® At the top of the figure is another sharper projection, which is the basal portion of a foliage leaf. Subtending each of the projections from the surface of the stem noted above is a fibrovascular strand, which has recently come off from the central cylinder. Fig. 7 shows part of the foregoing more highly magnified, to make clear the rela- tions of the outgoing traces to the stele of the stem. With the greater magnification an additional trace can be seen emerging from the central cylinder on the lower right hand. In passing out none of these three traces subtends a gap in the central cylinder, which in this region is a continuous fibrovascular tube. In the upper region of the stem, particularly where it gives rise to sporophylls, as BERTRAND has pointed out,’ the central cylinder breaks up into separate strands, much as happens in the upper part of the axis of Phylloglossum. In isolated transverse sections one often sees appearances such as are represented in figs. 10 and rz of the present article. On the strength of such evidence Miss Syxes® has asserted that there are foliar gaps in Tmesipteris. Her own figures, however, cannot be reconciled with this statement. On page 71 she represents sections taken at various heights through a portion of the stem, and makes a diagram of the bundle arrangement in this region. According to her figures the gaps are mainly on one side of the central cylinder or stele, and no less than three traces are related to one of these, that is, they are derived from the fibrovascular strands along its lateral margins. Three other traces originate near smaller stelar lacunae and one comes off — from any gap. A greater inconstancy in the mode of origin of traces could scarcely be imagined. A general acquaintance with filze vascular anatomy should make it clear that true foliar gaps 17 the same region of the stem should be nearly of a size and sho z occur immediately above a single leaf-trace. This state of affairs 18 ® Miss SyKEs prefers to regard this as a fertile branch. cis 7 Recherches sur les Tmesipteridées. Archiv. Bot. du Nord de la France se 1882. 8 Anatomy and morphology of Tmesipteris. Annals of Botany 22:63-89- ih 1908] JEFF REY—FOLIAR GAPS 247 very far from being realized in Tmesipteris as described by Miss YKES. ‘The conditions are in fact the same as those found in the corresponding region of the stem in Phylloglossum. Miss SyKEs has been so good as to loan her sections, and the series, although hot complete, vouch for the general accuracy of her figures. One fact of importance appears, however, to have escaped her notice, although it is clearly indicated in the sections, namely, that in every case the outgoing strands of appendages originated opposite the strands of the central cylinder and did not subtend any gap aé their point of origin, although some of them by a subsequent oblique course, as in Phylloglossum, seemed to subtend the stelar gaps. Appearances of this kind have been brought to the attention of Professor Bower, and he figures one such section on page 420 and again on page 487 of his recent work.° He expresses the opinion that his figure overthrows the hypothesis of JEFFREY on the lycopsid side. He further adds in a footnote: “The Botryopterideae are not phyllosiphonic; thus the anatomical distinction of JerFrEy breaks down on both sides.” In this added statement he is even less happy than in the original one, for he is apparently unaware that ferns with a protostelic central cylinder cannot possibly be phyllosiphonic, that is, possess foliar gaps. In all of the Botryopterideae in which the origin of the foliar strands has yet been described the central cylinder is protostelic. Professor Bower is in general not entirely at home in discussing anatomical facts. As a further example of this, may be cited his Statement that Alsophila excelsa, as described by GWYNNE-VAUGHAN, shows a “transition from the cladosiphonic to the phyllosiphonic” Condition in the young plant. Professor TANSLEY in a review of Professor BowER’s book?° very properly criticizes this singular mis- understanding in the following words: “Mr. GwyNNE-VAUGHAN will be probably surprised to learn that he has shown a ‘transition the cladosiphonic to the phyllosiphonic’ state in Alsophila excelsa. What really exists, of course, is a transition from protostely 0 siphonostely, and protostely is not a monopoly of the microphyl- lous forms, but is found equally among the primitive ferns.” It Cannot be too strongly emphasized that, especially in difficult cases, ® The origin of a land flora. London. 1908. : *° New Phytologist 7:126. 1908. 248 BOTANICAL GAZETTE [ocroBER like those occurring in the reduced Lycopsida, thin serial sections are necessary to a proper understanding of the real anatomical relations. It may be stated in conclusion that there are no real foliar gaps in Tmesipteris and that statements as to their presence depend on errors of observation and interpretation. In Psilotum leaf-traces are absent in the case of the vegeta- tive leaves, but as the angles of the stellate central cylinder sub- tend the ridges of the stem from which the leaves take their origin, there can be no question of the presence of foliar lacunae in this genus. Traces are present in the case of the sporophylls, but as these in general occur on the smaller terminal branches, where the stele is solid, they do not serve to elucidate the subject. It is of par- ticular interest that the leaf-traces should sometimes disappear altogether in the case of the small-leaved forms (the Lycopsida). The writer has called attention to this condition as occurring in the case of the basal foliar sheaths of the smaller branches of Equisetum.” EQUISETALES It is in regard to the supposed existence of foliar gaps in the equise- tal series that the writer has received the most weighty criticism. Dr. Scott in his masterly treatment of Paleozoic botany in Progressus ret botanicae, adopting the present author’s division of vascular plants into two phyla, the Lycopsida and Pteropsida, states that it 1S “open to much criticism; the general grouping however has sufficient claims to be a natural one, to afford at any rate a basis for the dis- cussion of affinities.” The only feature “open to criticism” ated which Dr. Scorrt lifts the veil is in regard to the absence of foliar gaps in Equisetum. His words are as follows: “The absence of foliar gaps, upon which JEFFREY lays stress, may hold good in the case of Archeocalamites, but if I rightly interpret the structure, ee are present in the Calamariaceae as well as in the recent genus. It will be the writer’s task to show that not only are foliar gaps absent in the older genera of the Equisetales, but that they also do not occur in the living genus Equisetum. . D Professor CAMPBELL’s criticism of the present writer’s work 0 ; ist. *« Structure, development, and affinities of Equisetum. Boston Soc- Nat. His Memoirs 5: no. 5. p. 176. 1908] JEFFREY—FOLIAR GAPS 249 Equisetum’? carries less weight on account of his lack of first-hand familiarity with the extinct members of the Equisetales, a necessary basis for the discussion of a group which has its history so largely in the past. His first objection is that the vascular system of Equise- tum is, on the basis of growing point development, of cortical origin and consequently cannot belong to the central cylinder, a term which in this case, according to Professor CAMPBELL, must be restricted to the pith, since it alone takes its origin from the sacrosanct region of the plerome. — It is perhaps too late to discuss conclusions ‘drawn from growing point morphology; they often lead rather to a reductio ad absurdum than to any useful or logical results. Professor Bower has set a very good example in his recent book in throwing the growing point theory and the octant theory overboard."’ Professor CAMPBELL sees no reason why there should be an attempt to reduce the vascular system of Equisetales to either of the types found in the other phyla of the pteridophytes. He further adds that the equisetal series Presents resemblances which “indicate a real although extremely remote relationship with the lower ferns,” thus committing the very error he previously condemned. Professor CAMPBELL also attaches 4 good deal of importance to the presence of multiciliate antherozoids as an indication of affinities, and regards this feature both in the Equisetales and Isoetaceae as indicative of filicinean affinities. His Views in both instances ‘are at variance with those of modern paleo- botanists, It will be well in our discussion of the Equisetales to begin with the living genus and thence go backward, for only in the living form 'S It possible to study the anatomical relations with necessary com- Pleteness. The reproductive axis of Equisetum will also afford a _ Petter starting-point than the vegetative, since it is a well-established Principle of the new morphology that the reproductive structures are Se likely to retain ancestral characters than the vegetative ones. Fig. 3 shows a longitudinal section through one of the fibrov: Strands of the cone of Equisetum telemateia, at a region where a trace 'S being given off to a sporophyll. It will be noticed that the sporo- Phyll trace passing off on the left of the figure goes outward and *? Affinities of the genus Equisetum. Amer. Nat. 39:273-285- 1995: *S Origin of a land flora, chaps. 14 and 42. 250 BOTANICAL GAZETTE [ocTOBER upward, without causing any break in the continuity of the fibro- vascular strand of the axis from which it is derived. On the inner side of the axial strand is to be seen a longitudinal space, the protoxy- lem lacuna. ‘This is continuous through the nodal region in the cone, although in the vegetative axis, as will appear below, the lacuna is interrupted below each so-called zone of nodal wood. The con- dition of continuity through the nodal region presented by the pro- toxylem lacuna in the cone of Equisetum is paralleled by similar conditions described by WrtL1AMson in the nodal region of Cala- mites. Fig. 2 represents a transverse section through the cone of the same species of Equisetum which makes clear the topography of the sporophyll trace and its corresponding axial strand as seen in this plane. There is no indication of any gap in the strand of the axis corresponding to the outgoing leaf-trace, which exactly subtends it. The examination of a large number of sections has convinced the author that foliar gaps do not in any case occur in the cone axis of Equisetum in connection with the passing-off of the traces of the sporophylls. The sporophyll trace is only about one-third to one- fourth the magnitude of the axial strand from which it arises, and consequently if any indication of a gap were present it would be clearly recognizable. Fig. 1 shows a general view of a cross-section of the cone of Equisetum telemateia, indicating the relation of several sporo- phyll traces to their corresponding axial bundles. In the cone the foliar traces are vertically somewhat displaced on account of the crowded arrangement of the peltate sporophylls, so that even ™ accurately transverse sections all of them are not cut at the same level. On the left of the figure a trace has recently left its corre- sponding axial strand. The next foliar trace to the right 1s mu farther out in the cortex than the first. The interval, corresponding to the next axial strand, does not show a trace, as this is not in the plane of section for the reason indicated above. In the cas¢ of ge fourth trace the conditions are much as they are in the second; while the fifth trace is just leaving its axial strand. It will be ur by inspection of the whole figure that in each case where a sporophy trace is present, it subtends the axial bundle from which it was der! in the lower part of its course. There is accordingly no foliar < present. These micro-anatomical results only serve to confirm 1 1908] JEFFREY—FOLIAR GAPS 251 statement made by the author, in his memoir on Equisetum, con- cerning the frequent failure to alternate at the nodes, which is char- acteristic of the strobilar strands of that genus. This feature is illustrated photographically in pl. 30, fig. 3, of the memoir. The author’s critics do not appear to have found this evidence sufficient. Itis important to insist on the correspondence of the micro-anatomical absence of leaf gaps in the cone of Equisetum with the non-alterna- tion of the axial strands of the cone at the nodes, because in some of the fossil forms we have only the latter evidence to go upon. It is perhaps a wise conservatism on the part of Dr. Scort to reject the evidence based on the frequent lack of alternation at the nodes, as seen in preparations of the bundle course in the cone of Equisetum. He can scarcely fail to be convinced by the microscopic demonstration of the absence of foliar gaps which has been given above and as represented in figs. z, 2, and 3. If it is reasonable to define a foliar 8ap as a gap in the wall of the stele, or one of its component strands mM case the stele is not a continuous hollow cylinder, immediately above a leaf-trace, there are certainly no foliar gaps in the cone of Equisetum. The writer has satisfied himself that foliar gaps do Rot occur even when there is more or less complete alternation of the strands in the cone. £E. telemateia has been chosen for illustra- tion on account of the large size of the structures present. Similar tesults in every way are shown by E. arvense and E. hiemale. It is now possible to turn with advantage to the examination of the Outgoing foliar traces of the vegetative branches of Equisetum. As 'S well known, the internodal bundles of one segment of the stem in Equisetum alternate with those of the next, in this respect presenting * contrast to the condition of the strands in the cone and in the more ancient extinct genera of the phylum. The internodal strands of Successive segments of the stem are joined in the region of the nodes by the so-called “nodal wood,” which consists of a dense mass of short reticulated tracheids forming ‘a completely closed ring. Fig. 5 shows a longitudinal section through an outgoing leaf- race and its corresponding cauline bundle. A large lacuna, the Protoxylem cavity, is seen on the right of the axial strand. This dis- ‘ppears below the so-called “nodal wood.” The outward course of the foliar trace is steeply upward, in contrast to that of the sporophyll 252 BOTANICAL GAZETTE [ocToBER trace. Its tracheids obviously take their origin in the region of the protoxylem lacuna and below the “nodal wood.” If the usual definition of a node be accepted, as marked by the outgoing leaf- traces, the so-called “nodal wood’? of Equisetum in reality is above the node. Fig. 4 shows a transverse section through a part of the “nodal wood” intervening between the bases of two branches. The leaf-trace lies just outside the mass of reticulated tracheids which compose the wood of the “node.” It is obvious that there is no break in the mass of tracheids corresponding to the leaf-trace. Above the incorrectly designated “nodal wood” are the internodal bundles of the next segment of the stem, and between these are parenchymatous gaps, which on account of the alternation of the internodal bundles in different segments are above the leaf-traces, since the latter take their origin from the bundles of the lower internode. Professor CAMPBELL and Dr. Scorr regard these as foliar gaps. They lack, however, one important feature of foliar gaps, for they do not occut immediately above the traces, as should be the case with true foliar gaps. All other foliar gaps with which we are acquainted show this feature. The onus of proving that the internodal lacunae of Equisetum are really foliar gaps appears consequently to lie upon the investigators who claim that they are to be regarded as such. It will be clear from the anatomical facts described above that in view im the relation of the leaf-traces to the so-called “nodal wood” it is quite incorrect to designate the ring of tracheids which lies above the out- going leaf-traces as “nodal wood.” It can only be called accurately supranodal wood. This distinction is a very important one to make, moreover, on phylogenetic grounds. » As a sequel to the description of the actual anatomical relations of the outgoing leaf-traces of the vegetative stem of Equisetum, . is natural to proceed to the discussion of the evolutionary OF phy genetic significance of the observed facts. The following citation from the memoir on Equisetum may appropriately be in uced ih this point: “But Srur has shown that in the Ostrau beds, pas*’ from the lower to the higher strata, a series of forms, — ramifer Stur, C. cistiformis Stur, C. approximatiformis Si C. ostraviensis Stur, represents transitions from the ment of Archeocalamites, represented in pl. 1, fig. 15, to that 1908] JEFFREY—FOLIAR GAPS 253 setum, represented in fl. 1, fig. 16.” It is obvious from the data of Srur, which have never been called in question, that the older Calamites were without the alternation of the strands in the region of the nodes which is characteristic of the more modern Calamites and the stem of the living Equisetum. It will be clear from the description of the anatomical conditions present in the cone of Equi- setum that absence of alternation brings with it the complete absence of foliar gaps. The writer in his memoir has suggested that the explanation of the peculiar features of the foliar traces in the vegetative stem of Equisetum is to be found in the past history of the phylum to which it belongs. Dr. Scorr would prob- ably agree to the soundness of this proposition, for example, in the case of the older living gymnosperms. ‘There appears to be no reason to make an exception in a group which has at least so long a past as the Gymnospermae. In the non-alternating arrangement of the inter- nodal strands, characteristic of the stems of the older Calamites (which is still largely represented in the cone axis of the living genus), there were no foliar gaps immediately above the outgoing foliar traces. As the relations of the internodal strands of one internode to those of the next became changed in the progression from the archeocala- mital to the equisetal mode of arrangement, the leaf-traces naturally came to lie opposite the gaps between the internodal strands of the next higher segment of the stem. But with the conservatism which is one of the most interesting characters of leaf-traces in general, they retained in Equisetum their old anatomical relations to the central cylinder of the stem. ‘That is, they still pass off in the vegetative stem of Equisetum without leaving any true foliar gaps. The lacunae in the internodes cannot be regarded as foliar gaps, since they are not immediately above the foliar traces, but are separated from them by the depth of the so-called “nodal” wood! The explanation offered 'S a reasonable one in view of the past history of the group, and on those who do not accept it is placed the burden of some other more teasonable elucidation of the peculiar anatomical relations of the leaf-traces in the genus Equisetum. a The writer is credibly informed that Dr. ScoTT is of the opinion that the internodal gaps in the genus under discussion are de facto foliar gaps. This is a somewhat surprising opinion on the part of 254 BOTANICAL GAZETTE [OCTOBER one whose brilliant investigations on the anatomy of the cycadean peduncle have put the whole subject of the affinities of the cycads with the lower extinct gymnosperms in a new light. Dr. Scort from his discovery of centripetal xylem in the peduncles of the reproductive axes of certain living cycads reached the conclusion that their ancestors with strong probability possessed similar bun- dles in their vegetative stem. This condition is in fact realized in certain of the Pteridospermeae, particularly in Lyginodendron, which Dr. Scorr regards as a probable ancestor of the cycads. There can be no question that Archeocalamites and Calamites are very much more nearly related to Equisetum than is Lygindodendron or any similar form to the living cycads. It follows that the reproduc- tive axis of Equisetum is much more likely to perpetuate the ances- tral characters of its stock than is the cycadean cone. It appears to have been shown above beyond any doubt that the equisetaceous strobilus perpetuates both the non-alternating strands and the com- plete absence of foliar gaps of the oldest calamitean forms. In - light of these facts there can be no reasonable doubt that the peculiar anatomical relations of the vegetative foliar traces of Equisetum ate likewise persistently retained indications of the ancestral condition, for although the shifting of the internodal strands in the course of evolution has caused them to subtend the gaps between the strands of the next upper internodes, they still leave the central cylinder without giving rise to true foliar lacunae, and are moreover separated from their apparent gaps by the whole depth of the supranodal wood. Collateral evidence of the correctness of this view of an even more cogent kind has been discovered, but is reserved for a subsequent communication. The older members of the equisetal alliance may now ne a sidered. Wess in one of his superb and classic monographs se! n Carboniferous Calamites'+ has published a number of illustrations of calamitean cones. On ls. x and 2 are figures of the genus sue annularia, which show clearly the phenomenon of no peer” at the nodes of the cone. Pls. 3 and 4 show the same arse di af cam in the well-known genus Calamostachys. In pl. 9 a simi . ‘4 rte Vv. ‘4 Steinhohlen-Calimarien, Atlas zu denAbhandlungen Gelog. Specialka Preussen 21; Berlin. 1871. 1908] JEFFREY—FOLIAR GAPS . 255 tion is figured in the cones of the remarkable genus Cingularia. Our information on the subject of the strobilus of the important calamitean genus Palaeostachya has recently been materially increased by the important investigations of Hicki1NG.'5 This author states: “From an examination of the numerous sections cut more or less transversely through the node, I feel little doubt that no regular pectination occurred; while on the other hand one or two sections showed features which seemed explicable only on the assumption that an occasional communication (probably irregular) did occur between adjacent bundles.” The conditions in this genus of calamitean cone would seem accordingly to have approximated very, closely those existing in the strobilus of the modern Equisetum, so far as the course of the bundles in relation to the nodes was concerned. This resem- blance is all the more striking because, lower down on the same page, the author states that the sporophyll trace left the axial strand with- out giving rise to any foliar gap. His words are “no gap ts left in the main bundle.” The italics are those of the present writer. “The main bundle” here means the bundle of the axis from which the sporophyll trace was derived. It will be readily inferred from the various Citations given above that, in spite of the conviction expressed by Dr. Scorr that foliar gaps occurred in the vegetative stem of the Calamites, they must have been generally absent in the cones of the more important calamitean types. There seems accordingly little rea- son to doubt, when the foliar relations of the more modern Calamites are fully worked out, since the course of their internodal strands resem- bled that found in Equisetum, that they will prove to be very similar to those of the living genus; and, in view of the similarity shown above in the fibrovascular arrangements of the cone, will be susceptible of a similar interpretation. This follows all the more certainly because $0 distinguished an authority as Dr. Scorr himself states, in his Studies in fossil botany: “Thus the calamite, so far as anatomy goes, ‘S simply an Equisetum with secondary thickening.” The conditions in Archeocalamites, the oldest calamitean genus, = particularly significant. In this form one of the most character- Stic features was the failure of the primary fibrovascular strands of the Vegetative stem to alternate at the nodes, as they do in the more ‘s Anatomy of Palaeostachya vera. Annals of Botany 21:375- 1998. 256 BOTANICAL-GAZETTE locroBER — modern Calamites and in Equisetum. It follows that there could have been no foliar gaps in this genus, if the general anatomical conditions were like those found in the rest of the calamitean stock, as has already been indicated by the present writer in the memoir on Equisetum. Our knowledge of the cone of Archeocalamites is very incomplete and nothing is known of its anatomical structure. It may be stated with some confidence, if credence is to be attached to the doctrine of descent and to the general principles of modern plant anatomy, that the equisetal stock entirely lacks foliar gaps immediately above the outgoing leaf-traces. Dr. Scort’s statement that in respect to their vascylar anatomy the Equisetales “reach the level of the simpler gymnosperms or dicotyledons” (Progressus rei botamicae, p. 157) will apparently, as a consequence, need some revision. There further seems to be no reason to doubt that the Equisetales are quite typical Lycopsida in the sense defined in the writer’s two memoirs, and are as a-consequence far removed from any mere affinity with any of the pteropsid series. ; It may be added that there seems to be no reason at the present time, on anatomical grounds at any rate, to suppose that the Pterop- sida had a sphenophylloid or ophioglossaceous origin from the Lycopsida. Neither Pseudobornia, of the reproductive organs of which we know little and of the anatomical structure of which we are entirely ignorant, nor Ophioglossum, of which the characters anatomical and reproductive are entirely filicinean, can serve . phylogenetic link between the primitively small-leaved veritrisporan- giate (adaxial) forms (Lycopsida) and the palingenetically large-leaved dorsisporangiate (abaxial) forms (Pteropsida). As Professor bai LEY has recently put it in a review of Professor Bower's Origin of 4 land flora,*° “on the general point of the relation of the ‘microphyll " the ‘megaphyll,’ there is no evidence of any capacity of the micto” phyll to evolve the megaphyll.” Summary 4 1. True foliar gaps occur immediately above their corresponding leaf-traces and are not lateral to the leaf-traces. super 2. Foliar gaps are absent in Phylloglossum, although os: © New Phytologist 7:125. 1908. 1908] JEFFREY—FOLIAR GAPS 257 ficial examination of the anatomy of this genus might lead to the con- clusion that the perforations in the tubular stele, which are sometimes lateral to the outgoing leaf-traces, are to be regarded as true foliar lacunae. 3. Foliar gaps are likewise absent in Tmesipteris, and recent statements as to their presence are based on misinterpretation or misconception. Perforations in the stele are here also found some- times lateral to one or more leaf-traces, but these cannot be regarded as true foliar gaps. 4. Foliar gaps are absent in the Lepidodendreae and the Sigil- lariae, but in the more modern species of the latter perforations of the tubular central cylinder are sometimes found, which have the same relations and are susceptible of the same explanation as are the similar perforations in Phylloglossum and Tmesipteris. 5. Foliar gaps are unquestionably absent in the cone axis of Equisetum, and on the basis of comparative anatomy are absent also in the vegetative stem. Similar statements apply to the reproductive and vegetative axes of Calamites. Archeocalamites has no foliar 8aps in its vegetative stem. 6. The Lycopsida as defined by the author are clearly marked off from other plants by a palingenetically microphyllous habit, the absence of foliar gaps in the tubular stele, and by the possession of or with adaxial sporangia. They constitute a great natural Phylum, In conclusion the writer wishes to express his thanks to Miss SYKEs, Professor A. A. Lawson, Professor G. J. Prerce, Dr. Hot- MAN (Stanford University), and Mr. L. A. Boopze for material which they have kindly put at his disposal. HARVARD UNIvERsItry EXPLANATION OF PLATES PLATE XVII Fic. 1.—Transyverse section of part of the cone of Equisetum telemateia. X 15. Fic, 2.—Transverse section showing the axial bundle and its outgoing foliar trace of the cone of EF. telemateia. X25. 'G. 3.—Longitudinal section of the same. X25. i Oe eee section through the supranodal wood of the vegetative 258 BOTANICAL GAZETTE [OCTOBER axis of the same species of Equisetum, showing the absence of a foliar gap corre- sponding to the leaf-trace which lies in the cortex. X25. 1G. 5.—Longitudinal section through a vegetative node of the same species of Equisetum, showing the departure of the leaf-trace without causing any gap in the supranodal wood. PLATE XVIII Fic. 6.—Transverse section of the stem of Tmesipteris tannensis. X15. Fic. 7.—Tranverse section of the same, showing the relation of the outgoing traces to the central enna X30. Fic. 8.—Copy of a figure from BERTRAND, showing the departure of the traces of the lower mite from the upper region of the peduncular strands in Phyl- loglossum Fic. 9. rofl eneveries section of part of the central cylinder of Lepidophloios Harcourt. Fic. 10.—Transverse section through the middle region of the cone in Phyl- loglossum, showing an relation of the leaf traces to the central cylinder. X60. Fic. 11.—Transverse section through the central region of ee cone in another example of Physical showing two apparent “foliar gaps.” X60. IG. 12.—Transverse section through the same cone slightly lower down, showing the connection of the foliar strand with the side of the apparent foli gap. X60. Nore.—Figs. ro, 11, 12 are all made from herbarium specimens. In fig. 12 the action of caustic alkali has not quite restored the size of the cells in the gap on the right of the central cylinder; it should appear the same size as that shown op the right of fig. I BOTANICAL GAZETTE, XLVI PLATE XVII Nf { 4 4 hs % 4. Le i y prvi5 38 eng 2 Vie —— oh : eon Ps Cites s 54 g ry as = Ge. y ~ 2.6 3, YT pa» 3S Ae Rae as 1 Cees Vay bad, yy ae . g | 4 4 i Rg Ss ERS Dey sae DH OIA oa AY AMAR } TAM eisgh pentelss 1: : TAOS A ] Wy DAV be) 4 ee FS 1 eilest \ : aeege aa & — ane ee on ae Oe JEFFREY on LYCOPSIDA BOTANICAL GAZETTE, XLVI PLATE XVIII oo 8 @ Ch *& %% @ on a & me ae ee Lt Bees “> aad ho *@. 4) r & > 9 ry ae & Oo bx r ua i * a, e ae ee ame. Se &, <7} see ae. 5 Os 2 ae, ea #, o@ sees oar ae @-@* a S8e. .- CSS ss Oo PX SL O rn est, oe, a rity pat gt Diep: Oo '¢. ae rs ’ PE ie L ses A ~ gO Car ete Sotore Bre es ey ty 33 JEFFREY on LYCOPSIDA EFFECT OF ILLUMINATING GAS AND ETHYLENE UPON FLOWERING CARNATIONS CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 116 WILLIAM CROCKER AND LEE I, KNIGHT (WITH FOUR FIGURES) 1. Historical As early as 1864 observations were recorded on the effect of illuminating gas on vegetation. GrRARDIN (1) called attention to the phenomena of gas injury to trees as reported from various places in Rouen, Berlin, Hamburg, Hanover, etc. He especially investigated injury done to Italian poplars which had come into use as shade trees along the highways. He made a chemical analysis of samples of soil taken three feet from leaks in the gas pipes, and found inflam- mable oil as well as sulfur and ammonia compounds present. R. VircHow (2) expressed an opinion that coal gas is especially injurious to vegetation. Kny (3) was one of the first to test the injury experimentally. He used three sound trees in the Berlin Botanical Garden, each about twenty years old—one maple and two lindens. Gas pipes were carefully laid 84°™ deep and the gas used was freed of sulfuretted hydrogen. The two pipes were laid in a circle about the maple, and four burners were attached at a distance of 118°" from the trunk. Near each linden tree were two burners, tro" from the trunks. The gas escape was measured daily. (t) Maple received daily.................-- 12.9 cubic meters (2) First linden 2g ee 11.7 cubic meters (3) Sectind tinditcc: 4 cue eas 1.6.cubic meters The experiment was begun July 7 and lasted for (1) and (2) a half- year, for (3) a full year. First a Euonymus (E. europea) near the maple died, then the maple lost its leaves (September 1). At the same time an elm near by showed injury. September 30 the first linden showed signs of injury. On October 12 the first linden lost ts leaves, and on October 19 the second, while other lindens in the 8arden were yet green. An examination of roots one-half inch in diameter showed a blue coloration extending out from the middle 59] [Botanical Gazette, vol. 46 260 BOTANICAL GAZETTE [OCTOBER toward the periphery. The following spring the maple, elm, and Euonymus bush showed no signs of life. The lindens produced foliage, but the leaves were bleached and smaller than usual. Dried cambium and a rich growth of fungi were further indications of injury. Similar investigations were carried on by SPATH and MEYER (4). In one case during the summer a little less than 1%™ of gas diffused daily through 17.8%-™ of soil in a wooded plot. The roots of all the trees were killed within a few days. During four winter months the same amount of gas was allowed to escape into a wooded plat of twice the above area. In this case Platanus, silver poplar, Ameri- can walnut, and Ailanthus were killed; the maple and horse chestnut were greatly injured; while the linden showed no injury. In another experiment 0.0185°"-™ of gas was daily distributed equally among seventeen trees. The experiment lasted from April 11 to June 27. Before May 30 six of the more sensitive trees had died. By June 21 all the others, with the exception of the rough-fruited maple, had slackened their growth. The leaves of the injured trees were a pale green or yellow, and most of the younger roots were dead. According to the statement of the gas inspectors, their methods were not capable of detecting such light leaks as are shown in this experiment. These investigators found that when the surface of the soil is compact, the gas may travel long distances before reaching the surface. An instance is cited of gas traveling from a leak on one side of a street to a cellar on the opposite side, where it became evident by an unbear- able smell. These investigators concluded that trees are far nas sensitive to gas leaks during the winter than during the growth pe im: They also found much more rapid injury where the surface ot the soil was packed. The small quantity of gas necessary to kill and the great distance that gas travels through the soil serve to empha- size the danger to which trees are exposed. i GR H. EvLenserc (5), besides summarizing the results given 1D previous literature, adds the birch to the list of less sensitive te J. Bouu (6) grew slips of water willow in water through nie Sas was passed. He found that they produced only short roots 2” that these soon died, as did also the buds. The twigs themselves remained alive for about three months, until, as he believes, the 1908] CROCKER AND KNIGHT—CARNATIONS 261 reserve food had been exhausted. In another experiment he found that soil impregnated with gas was very poisonous to plants, for seeds put to germinate in it started, but their roots soon died. A Dracaena planted in such soil died in ten days. Far less injury was shown when a given quantity of gas was in contact with the portions of the plant above the ground than when the same quantity came in contact with the roots by being passed into the soil. The roots, he concludes, are most sensitive to gas injury. He found potted plants of Fuchsia and Salvia only moderately sensitive to illuminating gas that was allowed to bubble through the soil. LACKNER (7) states that camelias, azalias, cacti, and ivy are much ‘ injured if kept in rooms where illuminating gas is burned; while palms, dracaenas (Acuba japonica), and many other plants escape uninjured. He asserts that it remains to be determined whether it is escaping portions of unburned gas or products of incomplete combustion that produce the injury. C. WrHMER (8) calls attention to a severe case of gas poisoning in Hanover. Thirteen elm trees along a street showed injuries vary- ing with the distance they stood from a leak in a gas pipe. In late winter a number of them showed brown discoloration of the inner bark, and a falling-off of bark in large patches extending up the trunk six feet from the ground. No blue discoloration of the roots *ppeared as was reported by Kny and other observers. The author asserts that the area of the injury was especially great because of the hard-packed Street above the leak. Motiscu (9) found that illuminating gas is more injurious to the ‘Sots of plants than chlorin or carbonic acid. Growth in length is retarded by ©.005 per cent. of illuminating gas. If uninjured and decapitated roots of corn are grown in illuminating gas, the former are Temarkably bent and retarded in their growth in length, while the latter grow almost straight and are comparatively vigorous. Under the influence of the gas the growth in thickness of the roots is Mereased, the greatest thickening occurring where the bending ® Sharpest. Wher a 10-20 per cent.’ mixture of illuminating gas “xerts a stimulus from one side, the roots respond negatively. NELjuzow (10) notes some very interesting effects of illuminating 84S upon the etiolated seedlings of peas and other legumes. WIESNER 262 BOTANICAL GAZETTE [ocroBER had already reported a horizontal nutation of these seedlings, which he explained as autonomic. RrimMeEr later explained this horizontal growth as a response to unfavorable conditions, especially lack of moisture in the air. NELJUBOW found that while this response always occurred in the dark in the laboratory air, it did not occur in the dark in a greenhouse or in the outside air. After determining that temperature and moisture were not factors, he sought the expla- nation in impurities of the laboratory air. He found that laboratory air passed through KOH, Ba(OH),, CaCl,, red hot CuO, and finally through Ba(OH), gave vertical seedlings; while similar treatment with the CuO unheated gave seedlings with the horizontal placement. This proved that some impurities (probably some of the constituents . of illuminating gas) of the laboratory air, which were oxidized by glowing CuO, caused this peculiar horizontal placement. He later produced the effect with mixtures of illuminating gas, He likewise tested a number of the constituents of illuminating gas. Acetylene produced this nutation, but was difficult to work with, because, 0? the one hand, a slight increase in concentration killed, and on the other, it rapidly disappeared because of its high solubility in water. ne part of ethylene in 1,000,000 of air gave the response, while one part in 4000 killed the majority of the seedlings. He likewise mer tions the fact that various other constituents (benzene, sulfur dioxid, hydrogen sulfid, and carbon bisulfid) of illuminating gas are highly toxic. -He makes no attempt, however, to determine the toxic limits of the several constituents, or to learn whether one or several deter mine the toxic limit of illuminating gas. a SHONNARD (II) mentions several manifestations of the injury of illuminating gas to trees, and describes an experiment with a potted lemon tree exposed to a flow of 1.07% of gas per hour. After eight days he notes the exudation of sap in considerable quantity from trunk and branches, as well as the discoloration and falling-off of the leaves. RicHarDs and MacDovucaL (12) tested the effect of carbon monoxid and illuminating gas upon various seedlings. a monoxid, heretofore considered neutral, was shown to be Scat was not so effective as illuminating gas, however, in modifying : rate and amount of growth of root and shoot, in retarding the differ 1908] CROCKER AND KNIGHT—CARNATIONS 263 entiation of the primary tissue, and in hindering the formation of chlorophyll. Gametophytes of certain mosses were found to be very resistant, suffering very little injury in high concentrations of these gases for three months. A more delicate moss, presumably Mnium undulatum, however, showed deleterious effects earlier. In Elodea and Nitella older cells were most injured, and the injury was shown by plasmolysis of the. cells. A considerable part of their experimentation with illuminating gas serves to confirm the results obtained by Motiscu, NEtyuBow, Boum, and others. The con- clusion that “illuminating gas affords, in addition to the action of carbon monoxid, the results of the action of other substances dele- terious to plants” seems to indicate that the work of NELJuBow and others was entirely overlooked. STONE (13) calls attention to the fact that very small leaks (2-3 per day) of gas may cause local injury to trees. Among manifesta- tions of gas-killing in trees, he notes the early appearance of an abundant growth of fungi in contrast to the relatively late appearance on other dead trees. In speaking of the distance gas may travel he says: “In gravelly soils we have known gas to travel 2000 feet without difficulty, when the ground is frozen, and escape into the cellar of a house ; whereas in heavier soils gas is more likely to be restricted to smaller areas.” RICHTER (14) and other investigators have pointed out a number of effects of impurities of laboratory air upon the responses of seed- lings. RIcHTER believes that in a number of cases the negative 8eotropism of hypocotyls is greatly weakened by these impurities. © points out that a one-sided illumination will produce far more nearly a horizontal position with than without these impurities. He likewise asserts that in many species the degree of horizontality from one-sided illumination indicates the degree of impurity of the ar. He found great variation, however, in sensitiveness in different Species even of the same genus. 2. Scope, method, and preparation of material It is quite commonly asserted that plants do poorly in houses ted with gas and especially is the flowering interfered with. Various inquiries have come to us from carnation growers as to the 264 BOTANICAL GAZETTE [OCTOBER effect of illuminating gas upon the flowering carnation. These growers claimed to have had heavy losses from gas that seeped from defective pipes through the ground into the greenhouses. In some cases it is claimed that the losses occurred during cold weather, when little ventilation was possible and when the ground was frozen, so that upward diffusion from the defective pipes was hindered and thereby lateral diffusion fostered. In all these cases it is claimed that the injuries ceased with the repair or removal of the pipes. Upon looking up the literature it was found that no accurate determinations were made upon the effects of illuminating gas and its constituents upon flowers, and that in no case have the toxic limits and relative toxicity of the several main constituents been deter- mined. In short, it is not known in any case whether the toxic limit of the gas is determined by the action of one constituent or by the combined action of several. To answer these questions is the put pose of the investigation here reported. This paper will deal entirely with the buds and flowers of the carnation, describing in detail the effects and toxic limits of illuminat- ing gas and ethylene. A later paper will give in detail similar data for the other main constituents of illuminating gas, as well as escribe the effects of illuminating gas and all its main constituents upo? the vegetation of the carnation. The work naturally falls into these two divisions, for, as will be shown by experiments described later, the flowers are far more sensitive to illuminating gas than is the vegetation, and the toxic limit of the gas on the flowers seems (from all the evidence of our experiments) to be entirely determined by the ethylene it contains. To determine the relative sensitiveness of buds and flowers oP sa one hand, and the vegetation onthe other, as well as the relat sensitiveness of buds and flowers of different ages, one series © experiments was carried on by exposing entire potted plants 1 = atinosphere containing small proportions of gas. This was done by setting the plants into an air-tight greenhouse within the laboratory greenhouse, and then running desired quantities of gas into ee tight greenhouse. This sort of experiment has some serious faults. It does not determine whether the flower is affected directly caer! gas contained in the air about it, or whether the effect is in . 1908] CROCKER AND KNIGHT—CARNATIONS 265 injury to the plant through the absorption of gas by the soil and later by the roots. Also no definite determination of the toxic limit of the gas can be made, for the amount absorbed by the soil is not determi- nable. To avoid such sources of error the buds and flowers still intact were exposed indiv idually to the desired concentrations of the gases. This was accomplished by the use of the apparatus shown in fg. I. Fic. 1.—For description see text. The bottle a is furnished with a three-holed rubber stopper. In one hole of the Stopper is a straight glass tube reaching nearly to the bottom of the bottle. A calcium chlorid tube (d) is attached to the Projecting end of this tube by means of a rubber tube furnished with : pinchcock ( (e). In the second hole of the stopper is a short bent glass tube (f), the outer end of which is furnished with a rubber tube and Pinchcock (g). The third hole in the stopper is small and is capable - having the stem of the carnation inserted from the side by a split, Which Teaches from the hole to the margin of the cork. In setting 266 BOTANICAL GAZETTE [OCTOBER up the experiment the cork is placed on the stem of the carnation by opening the cork at the split and inserting the stem. The flower or bud and the long tube are put into the nozzle of the bottle and the cork forced in until the whole apparatus is air-tight. The free end of the calcium chlorid tube is placed into a dish (h) of water or (with gases highly soluble in water) mercury; both pinchcocks (e and g) are opened; and suction applied to the tube / until the liquid rises to the small portion of the calcium chlorid tube, at which time pinch- cock g is closed. The desired quantity of gas which is now poured into the wide end of the calcium chlorid tube rises to the top of the liquid. A one-holed rubber stopper, furnished. with a tube and attached to a column of the same liquid as is contained in the dish, is now inserted into the free end of the calcium chlorid tube (d), and the pressure of the column allowed to force the liquid to the inner end of the long tube. This forces the gas into the end of the bottle farthest from the flower and allows a gradual distribution by diffu- sion. For ethylene and illuminating gas water was always used as the forcing liquid. In determining the toxic limits of illuminating gas and ethylene, 20-liter carboys were used; while smaller bottles were employed some of the earlier experiments with these gases, as well as with all the determinations of the least toxic gases. The question of ae effect of corking a bud or flower in a closed chamber of this kind naturally arises, and suggests a criticism upon the method. It was found that flowers opened without any apparent injury when corked in flasks of only one liter capacity. In all checks and in all eS where the concentration of the injurious gas was below the toxic limit, the flowers bloomed normally while yet in the bottles. To avo undue rise of temperature within the chambers basket-covered CaF boys were used. The experiments were carried on in the labor atory greenhouse during the months of May to September. The tempe* ture in the experiments reported varied from 20°-28°, and within this Tange no noticeable variation in toxicity appeared. Two varieties of carnations were used—the Boston Market and the pink Lawson. The two varieties vary so little in their sensitive ness and reaction to ethylene and illuminating gas that a description of the responses of one applies equally well to the other. 1908] CROCKER AND KNIGHT—CARNATIONS 267 To make sure that the effect produced by ethylene was not due to some impurity contained by it, parallel experiments were run with ethylene derived by two different methods: (1) by heating concen- trated sulfuric acid with absolute alcohol, and (2) by dropping abso- lute alcohol upon phosphorous pentoxid heated to 200° C. and later raised to 240°C. The ethylene derived from sulfuric acid was washed by the ordinary gas burette and pipette, as described by HEMPEL (15: 34-95); first in concentrated sulfuric acid (sp. gr. 1.84) to remove the aldehyde, and later in 33 per cent. potassium hydrate to remove the sulfur dioxid. In each case the washing was continued until no further absorption occurred. The ethylene derived from phosphorous pentoxid was washed similarly, and in addi- tion in copper sulfate (sulfuric acid solution described by HEMPEL, Pp. 316) for absorption of phosphene, if any should be present. Various samples of the ethylene derived in this way were analyzed. Bromin and fuming sulfuric acid absorbed 96-98 per cent. The unabsorbed portion proved to be air, coming from the generator chamber. The gases thus derived were diluted with air to form “Mixtures containing 2 per cent. ethylene. The toxicity of the two mixtures was equal. In discussing the composition of illuminating gas we can hardly do better than quote a paragraph from SrrH’s (16) General chem- tstry for colleges: The illuminating gas in Europe, and in many of the smaller cities of the United States, is usually coal gas; while in the larger cities of America it is almost always made from water gas. Coal gas is obtained by the destructive distillation of soft coal, and is freed from ammonia and tar by washing and cooling, and from hydrogen sulfid and carbon dioxid by passage through layers of slaked lime. The water gas, made by the action of steam upon anthracite or coke, being com- Posed of carbon monoxid and hydrogen, has no illuminating power. It is there- - “carburetted,” that is, mixed with hvdrocarbons, by passage through a Cylindrical structure filled with white-hot firebrick, upon which falls a small Stfeam of high-boiling petroleum. The relatively involatile hydrocarbons of Which the oil consists are thus decomposed (“cracked”), and gaseous sub- ere ot high illuminating power are produced. The following table shows Composition of each of these kinds of gas, together with that of oil ing” oe asia which is composed entirely of the products from “crack- 268 BOTANICAL GAZETTE [OCTOBER Components Coal gas Water gas Oil gas MN oe, Poe et 5.0 16.6 45.0 Heating gases : Ne et a 34.5 19.8 35-8 Hy pt ee ay Saas 49.0 42.5 14.6 codices to cag EE een 7.2 26.1 sees Imp vo OSIRIS El yt cen ce aa 2.4 1.1 Seer OU ln Tix 3.0 vee Rae OG 17.5 25.0 65.0 These are average numbers, and considerable variations from these propor- tions are often met with. The illuminants are unsaturated hydrocarbons, such as ethylene and acetylene, and the value of the gas for illuminating purposes depends on the amount of these particular components. _ The illuminating gas used in our experiments was water gas of the People’s Gas Light and Coke Company, drawn from a tap in the Botanical Laboratory. In numerous analyses of samples of this gas (see HEMPEL, p. 282) absolute alcohol absorbed 0. 2-0.6 per cent., and fuming sulfuric acid 1114 per cent. Absolute alcohol absorbs the so-called hydrocarbon vapors (mostly benzene); and fuming sulfuric acid the heavy hydrocarbons, including acetylene, ethylene, and their higher homologues. Bromin is often used as an absor of ethylene. Besides ethylene, however, it absorbs several other con- stituents of illuminating gas. In a number of analyses this reagent absorbed 9-13 per cent. A more definite determination of ethylene will be given in the experimental portion. At first the illuminating gas used was washed through 33 per cent potassium hydrate to absorb any traces of sulfur dioxid and hy drogen sulfid it might contain. This was found not to modify the toxicity, and hence the unwashed gas was used thereafter. The methods g deriving and purifying the other constituents (of illuminating gas) worked with will be described in the later paper, which gives ther effects. 3. Experimental ILLUMINATING GAS Se As a later paper will deal fully with the effects and toxic - of the constituents other than ethylene, we need make only 2 gen©""" statement concerning them here. A number of experiments were ™ 1908] CROCKER AND KNIGHT—CARNATIONS - 269 to determine the toxic limits of methane, carbon monoxid, acetylene, hydrogen, carbon bisulfid, and benzene to the buds and flowers. As would be expected, hydrogen was perfectly neutral when it com- pletely displaced the nitrogen of the air. In all the other constit- uents here mentioned, the toxicity was such that in the least amount of illuminating gas necessary to kill the bud no one is concentrated enough to reach sy Of its toxic limit. It is very probable, therefore, that these constituents play no part in determining the toxic limit of illuminating gas. It has already been stated that the absorption of hydrogen sulfid and sulfur dioxid does not modify the toxicity of the gas. This leaves, then, ethylene, the higher homologues of ethylene and acetylene, and certain aromatic sulfur compounds to account for the toxicity of the gas. All these substances except ethylene exist in very small percentages in illuminating gas. All evidence in the following experiments also points to the conclusion that there is fnough ethylene in the gas to account for its toxicity. The small greenhouse in which entire potted plants were exposed 'o the action of gas had a capacity of 1.69%™. In order to make comparisons easy between buds of the same size on the plants exposed and on the checks, corresponding buds were tagged with the same numbers. We need describe only one of these experiments. Potted Plants of the Boston Market were put into the small greenhouse in the evening and 2 liters of gas were run in at the end opposite the Plants, allowing a gradual distribution by diffusion. The plants "ere taken out the next morning to prevent injury by high tempera- ture. The following evening the plants were returned to the enclos- ure and left for 60 hours (the following two days being cloudy). At the time they were put in, 4 liters of gas were run in, and the same ‘mount Was added 48 hours later, there being at that time no per- ceptible smell of gas in the chamber. This experiment served to 4 (r) that the vegetation is far less sensitive to gas injury than the ; for there was no apparent injury to the vegetation; (2) plants remained vigorous , put out new buds, and later produced other flowers. € oldest buds (those showing color and just ready to open) and the Jos 8est buds (those less than o.6°™ in diameter) were the ones most _ Many of the medium-sized buds, however, escaped death, although retarded considerably in their growth. The older buds 270 ; BOTANICAL GAZETTE [ocroBER showed a slight growth of the petals, but never opened. Later they shriveled and turned yellow. Our experiments in which individual buds were enclosed and exposed to illu- minating gas began with liter flasks in which as much as 25°° of gas was used. The time of exposure was usually three days, starting when the petals were just . | | beginning to show. A gradual reduction 2 Fic. 2.—a, result of treat- of the concentration by reducing the Soeas rake ae Thies days amount of gas used and by increasing with r part of illuminating gas the size of the enclosure finally located mentor a Heaitet he the toxic limit. ‘The highest concent same length of time, with part tion did no apparent injury to the vege- of ethylene in 500,000. tation; but the effect upon the buds was made apparent by a failure to open, by a discoloration and withering of the petals, and by the projection of the stigmas. When using 1% of illuminating gas to 20,000°, the stigmas still project as shown m §- 2, a; 0.5°° of illuminating gas did not suffi- ciently retard the growth of the petals to cause projection of the stigmas, yet the buds never opened farther than shown in fig. 3, although the petals remained fresh for several days. Very young buds were also exposed to the last con- centration of the gas (1 part in 40,000, or 0.0025 per cent.) for a period of three days. The injury Was not apparent at first, and the buds remained Sreen for several days, but finally turned brown and withered. A series of exposures was also made on the open flowers. We selected for this work those that had just opened, in order to be sure that any ed change produced was due to the toxicity of the Fr. 3—Result of gas rather than to the natural death of the flower. treating a bud, just Here as well as in all the other experiments checks — a three were kept. F ig. 4, @ shows a flower before being gave with 1 pes corked ina 20-liter carboy; b, the same after being _ ethylene in 4.00% 1908] CROCKER AND KNIGHT—CARNATIONS 271 corked in a 20-liter carboy (containing air only) for 24 hours; ¢, a flower before being corked in a 20-liter carboy; and d, the same after being corked in 12 hours with o.5°¢ of illuminating gas. This shows that 0.5°° of illuminating gas per 20,000 (1 part in 40,000) causes the com- plete closing of the flower in 12 hours or less. Higher concentra- tions caused a more rapid closing and a marked inrolling of the petals. With 0.5°¢ per 20,000 and less the inrolling is not conspicu- ous. Even 0.2°° per 20,000 causes considerable closing in 12 hours, though not as marked as o. Bors The effect of duration of exposure was also tested. No injury was done to a bud just ready to open upon one day’s exposure to 2°° FIG. 4.—a, a flower that has just opened; b, the same after being corked in a 20-liter flask of air for 24 hours; c, a flower that has just opened; d, the same after being exposed 12 hours to 1 part of illuminating gas in 40,000; ¢, result of treating a flower that Just opened for 12 hours with 1 part of ethylene in 2,000,000. of gas per 20,000 (four times killing concentration for three days’ ©xposure), On a similar bud 5° for one day was considerably more 'Njurious than o, 5°° for three days. The stigmas did not project, but the petals were markedly discolored. During the entire period of experimentation there was no very marked variation in the toxicity of the gas used.’ eff = determining the toxic limits we located a concentration that produced the a while one-half that concentration did not. It is clear that this permits consider- © Va iati : é 272 BOTANICAL GAZETTE [OCTOBER ETHYLENE The experiments with ethylene were begun by exposing buds just beginning to show the petals to 1, 4, 4, 4, and 4°¢ of ethylene in 20 liters. In each of these concentrations the buds were killed on three days’ exposure. The usual signs of gas poisoning were noted; petals turned yellow and withered, and the stigmas projected. Since it was evident that these concentrations were far above the toxic limit, we resorted to the use of a 2 per cent. mixture of ethylene with air. Various amounts of this were used, until the toxic limits were definitely located. With 2°° of this 2 per cent. mixture in 20,000 (1 part in 500,000), the results were similar to that obtaining with 1°° of gas per 20,000 (1 part in 20,000). In fig. 2, b is a bud just showing the petals exposed to this concentration of ethylene for three days. Also 1°¢ of 2 per cent. ethylene per 20,000 (1 part in 1,000,000) gives results similar to that shown by 0.5°¢ of illuminating gas per 20,000 (1 part in 40,000). Fig. 3 shows the results of such an exposure for three days on a bud just showing the petals. The growth of the petals is not sufficiently retarded to make the stigmas conspicuous; the petals remain fresh for several days but never open farther. Where much less than 1°¢ of 2 per cent. ethylene per 20,000 was used with similar buds, three days’ exposure did not prevent their opening. When open flowers were exposed to the ethylene, it was found that 0.5°¢ of the 2 per cent. mixture in 20,000 (ie., 1 part in 2,000r 000) caused the closing within twelve hours. The result of such an experiment is shown in fig. 4, e. It is seen from the data given above that ethylene must form approximately 4 per cent. of illuminating gas to be the constituent that determines the toxicity of the latter. It becomes necessaTy oe to get an estimate of the fraction of the illuminating gas used ne is ethylene. We have already stated that no absorbent used in ga analysis absorbs ethylene alone. In a special absorption ch gsi packed in ice, 50 or more grams of bromin with 150°° of water we placed, and measured quantities of illuminating gas passed spat When the bromin water was partially discolored, showing 2? alm of complete exhaustion of the bromin, the resulting oil (a mixture “ ethylene dibromid and other compounds resulting from the erie 1908] CROCKER AND KNIGHT—CARNATIONS 273 of the gas constituents with bromin) was separated, washed with a weak solution of potassium hydrate, and later with distilled water. This oil was then dried with fused calcium chlorid and later frac- tionated. In the first distillation all the portion boiling between 129° and 134°C. was saved. This was later redistilled and the fraction boiling between 103° and 1 32° C. saved as representing the ethylene dibromid, since this compound boils at 131°C. About 3 per cent. of the dried material absorbed by bromin boiled between 30” and 132°C.; a small portion boiled at 129° C. or below. From this it rose up quickly to 131° C., where it again gave a considerable fraction. Then it rose rapidly to 139°C., where a considerable fraction distilled. In one trial, 208 liters of gas at 27° C. and under Pressure of 745.5™™ of mercury gave 1308 of dried oil; of this 44.28 boiled between 130° and 132°C. After correcting for pres- sure and temperature the following equation equals the percentage volume of gas that is ethylene: 22.4% 760X 44.2 X 300 208 X745:5 X178X273 In a second determination 1 38 liters of gas at 27° C. and 745.5™ org Save 31.68" of oil boiling between 130° and 132°. Cor- the ing for temperature and pressure, the following equation gives percentage volume of ethylene in this case: 22.4X 760X 31.6300 138X745 ..4X178X273 F = mst be stated, however, that according to WINKLER (17) the aes of ethylene by bromin is not complete, and farther that ing oe ethylene dibromid is necessarily lost in washing, dry- hishar pa distilling, ~~ that the percentage is probably considerably of other 7a obtained. It must be urged also that the presence broméd 3 with boiling points rather near that of the ethylene nds to make this fractionation less accurate. =2.9-+ per cent. =3.2 per cent. 4. General _ of great interest to know that the most delicate chemical test oan: gas in the atmosphere falls far short of detecting tests f that work havoc with the flowers of the carnation. The °F carbon monoxid are those used for detecting illuminating 274 BOTANICAL GAZETTE [OCTOBER gas. The most delicate application of the blood test (see HEMPEL, p- 225) will detect 1 part of carbon monoxid per 40,000. The iodine pentoxid test (see HEMPEL, p. 226) is of equal delicacy. If carbon monoxid forms 25 per cent. of illuminating gas, these tests will detect 1 part of illuminating gas in 10,000. . Upon three days’ exposure ! part of illuminating gas in 40,000 kills the young buds and the petals of the flowers just beginning to open; while 1 part in 80,000 causes open flowers to close upon an exposure of twelve hours. The so-called “sleep” or closing of the carnation is a source of considerable loss to growers and dealers, for flowers that once close never again open. This “sleep” is especially likely to occur with cut flowers brought into city markets. Some varieties are so disposed to react in this way that their cultivation has almost entirely ceased. We know several homes lighted with gas where cut carnations can be kept only a few hours without “going to sleep.” In one instance the displacement of gas lights by electric lights entirely overcame this difficulty. Our experiments show clearly that one cause of this sleep is traces of illuminating gas (ethylene) in the surrounding atmos- phere. : STONE (13), WEHMER (8), and others have shown that illuminating gas diffuses great distances through the soil, especially if there ® hard-packed or frozen crust over the top. This paper shows the extreme sensitiveness of the carnation to this substance. From these facts it is evident that carnation growers whose greenhouses are - the region of gas pipes must take great precautions against ee from this source. It would be interesting to know whether solid cement walls set into the ground for some depth on the side — si pipes would furnish sufficient protection against leaks of this kind. It is clear that, if (as our results seem to indicate) the group of illum nants, or more accurately if one constituent of this group (ethylen® determines the toxicity of illuminating gas, coal gas is foes less toxic than water gas, while oil gas is more toxic than either of others; also the toxicity reported by the German investigator | used coal gas is less than that shown by the gas of the great Am cities. While it seems probable that the limit of toxicity of illuminati gas on the flower of the carnation is determined by the ethylene 1908] CROCKER AND KNIGHT—CARNATIONS 275 contains, it does not follow that such is the case with all parts of plants or even with the flowers of all plants. It would be interesting to know the effects and toxic limits of illuminating gas and its con- stituents upon various double as well as single flowers. Similar data for the foliage of various plants such as Coleus, which is supposed to be especially sensitive to illuminating gas, would likewise be of interest, 5. Summary 1. The flowers of the carnation are extremely sensitive to traces of illuminating gas in the air. 2. With the Boston Market and pink Lawson three days’ Papeete '0 1 part in 40,000 kills the young buds and prevents the opening of those already showing the petals. The buds of medium age are considerably more resistant. 3- In the same varieties 1 part in 80,000 causes the closing of the open flowers upon twelve hours’ exposure. 4. This injury takes place directly on the bud or flower exposed and not indirectly through absorption by the roots. 5- No chemical test is delicate enough to detect the least trace of illuminating gas that will cause serious injury to carnations. 6. The “sleep” of the carnation is probably often caused by traces of illuminating gas in the air. F 7- Ethylene is even more fatal to the flowers of the carnation. _ 8. Three days’ exposure to 1 part in 1,000,000 prevents the open- ng of buds just showing the petals. : 9. Twelve hours’ exposure to 1 part in 2,000,000 causes the closing of flowers already open. ; ‘S. There is much evidence that indicates that the toxic limit of inating 8as upon these flowers is determined by the ethylene it Contains, THE University oF CHICAGO LITERATURE CITED GIRARDIN, —, Einfluss des Leuchtgases auf die Promenaden und Strassen- - Jahresber, Agrikultur. '7:199-200. 1864. Ss : Vincuow, R., Einfluss des Leuchtgases auf die Baumvegetation. Jahresber. Agrikultur, 13-15:237. 1870-72. 276 BOTANICAL GAZETTE (ocTOBER 3- Kyy, L., Um den Einfluss des Leuchtgases auf die Baumvegetation zu priifen. Bot. Zeit. 29:852-854, 867-869. 1871. 4. SPATH AND Meyer, Beobachtungen iiber den Einfluss des Leuchtgases auf die Vegetation von Baumen. Landwirtsch. Versuchsstat 16: 336-341. 1873- 5. Evtenperc, H., Handbuch des Gewerbe-Hygiene 601. 1876. 6. Boxy, J., Sitzangsber. des Wiener Akad. Math. Naturw. Kl. 1873. Bot. Zeit. 32: 74-75. 1874. . Lackner, C., Monatsschrift des Ver fiir Beférd. des Gartenbaues in den Kgl. Preuss. Staaten 16:22. 1873. . Weumer, C., Ueber einen Fall intensiver Schadigung einer Allee durch juiabiieandiian Leuchtgas. Zeitschr. Pflanzenkr. 11: 267-269. 1900. Motiscu, Hans, Ueber die Ablenkung der Wurzeln von ihrer normalen Wachstumsrichtung durch Gaze (Aérotropismus). Sitzungsber . Kaiserl. Akad. Wiss. Wien 90:111-196. 1884. . Netyuzow, D., Ueber die horizontale Nutation der Stengel von Pisum sativum und cluiger anderen Pflanzen. Bot. Centralbl. Beih. 10:128-139- Igor. 11. SHONNARD, F., Effect of illuminating gas on trees. Dept. of Public Works, Yonkers, N. Y. pp. 48. 1903. 12. Ricwarps, H. M,, AND MacDoveat, D. T., The influence of carbon mon- oxide and other gases upon plants. Bull. Torr. Bot. Club 31:57-66. V4 13. Stone, G. E., Effect of escaping illuminating gas on trees. Mass. S Rept. pp. 180-186. 1906. ‘ 14. RicuTER, Oswaxp, Ueber den Einfluss verunreinigter Luft auf Heliotropis- mus und Geotropismus. Sitzungsber. Kaiserl. Akad. Wiss. Wien 115:205- ~J oo ¥ es ° 15. Dennis, L. M., HEmpet’s gas analysis. New York. 1 : 16. ma A., Giiied chemistry for colleges. New York: ” Century co 17. aceite Ct., Zeitschrift fiir Analyt. Chemie 28:269-289. Cf. HEMP” P- 230. FLORAL SUCCESSION IN THE PRAIRIE-GRASS FORMA- TION OF SOUTHEASTERN SOUTH DAKOTA SEROTINAL AND AUTUMNAL FLORAL ASPECTS CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY I17 LeRoy HarRis HARVEY (WITH FOUR FIGURES) Serotinal floral aspect Climatologically and florally the serotinal is perhaps the most distinctly demarked of the aspects. The climatological changes which set it off from the estival are quite generally appreciated, while the general blooming of the pioneer sod-formers during the early Part of July with the accompanying serotinal bloomers no less dis- Unctly marks it in a floral way. One records now less dissimilarity in aspect and tone on crest, slope, and base ; the more open association, however, still marks the ‘rest. The tone is determined by the dull-greenish vegetative stalks of Solidago rigida and Helianthus Scaberrimus, which occur copiously throughout the formation. It is relieved locally on lower slopes by the yellow of Ratibida columnaris and on upper slopes by the blue of Verbena stricta and the canescence of Amorpha; while Meriolix Serrulata, Brauneria pallida, Potentilla Hippiana, Erigeron ramosus, Polygala alba, and Euphorbia marginata, all of which extend over m the estival, are less influential. A few conspicuous forms are added In this aspect, but never of sufficient abundance to strongly nay the dull green of the tone given by the leafy stems of Soli- 4g0 and Helianthus. The Seneral flowering of A gropyron occidentale, Bulbilis dacty- a the Boutelouas, together with Kuhnistera purpurea and K : POoaEe, distinctly marks the inception of the serotinal aspect, which is terized by the gradual appearance of few but conspicuous Rte and the attainment of maximum flowering of late estival » Tather than by the addition of numerous forms as in the an [Botanical Gazette, vol. 46 278 Le) NOLLVEOdVAE 4 MALLVTaY | ALIGINOAH < QALY Tau NVayy | ‘OS pzreseayo BS uy | ° nN nS eS 8 WP begk | ° pzejoy - Lal Aysuaqut os anepy | © & a *yue0 Iod oe 5 aurysung | © > ssouIpnop «© 8 ure | | & toe g : moL | g ™ 2 | E || & | spepuvoy | §, 5 rs i . > wm sheq 9 Aypopea Oy AEMoP ~ z yuour oo ras tS. ToHIeIIp 3: Suyreasig | V2 6) weap bf nN B a Pi mmunrorpy o E LL ™ * BOTANICAL GAZETTE [OCTOBER vernal and estival aspects, only thirteen new forms appearing during the aspect. It is moreover the aspect of the sod- formers, “floral”? forms being represented by only six species. Several ruderals make their floral appearance in the formation dur- ing this aspect but, with the exception of Cassia chamaecrista; attain no conspicuous- ness. The serotinal is markedly a period of extremes, bringing about a change to which one is generally sensible. During the early days of July the weather settles and there is a long succession of long and intensely hot and dry days, which condition char- acterizes the entire serotinal aspect. Relative evaporation (table) is at an extreme, though slightly less (0.81) than in the estival, find- ing its explanation in the lower (0.4) hourly wind velocity and higher (8-5) relative humidity; the hot dry winds from the south and southeast are now coexistent with the highest mean temperature, the lowest esi daily precipitation, a low relative humidity, and a high light intensity. Thus evapora- tion and transpiration are augmented to @ precarious degree. The chresard shows a continued decreas® from the estival, being 6.5 per cent. on July 6 and 4 per cent. on July 24; while the aie age chresard is 5.2 per cent., the ie ‘ yet reached. The holard of crest ©! cent.), 4” per cent.), slope (12 per 78) base (12.2 per cent.) are now uly sie more nearly approximate than 1 aspects. : ;mum and Relative evaporation at a maximum 1908] HARVEY—PRAIRIE-GRASS FORMATION 279 the chresard at a minimum are thus the ecological conditions which strongly mark the serotinal floral aspect. SPECIES OF THE SEROTINAL FLORAL ASPECT Factes.—Bouteloua oligostachya,t B. hirsuta,t B. curtipendula,} Bulbilis dactyloides.*+ MARY SPECIES.—Kuhnistera purpurea,t Verbena stricta,*{ Ratibida columnaris,*; Kuhnistera candida,j Symphoricarpus occidentalis,*} Amorpha canescens.*t} SECONDARY SPECIES.—Agropyron occidentale, Carduus undulatus,* Euphor- bia marginata,* Hymenopappus filifolius, Calamovilfa longifolia, Polygala alba.* TERTIARY sPECIES.—Lygodesmia juncea, Lacinaria squarrosa, Brauneria Pallida,* Meriolix serrulata,* Eriocarpum spinulosum, Erigeron ramosus,* Potentilla Hippiana.* RUDERAL sPECIES.—Cassia chamaecrista, Onagra biennis, Amaranthus staecizans, Melilotus alba,* Chenopodium album, Lactuca canadensis, Apocynum cannabinum. : *From previous aspect. {Forming associations. _ Agropyron occidentale is the first of the serotinal grasses to bloom. Itis a xerophytic bunch-grass and occupies prairie crests, where it curs copiously, rarely even of facial rank. It is one of the pioneers of the bunch-grass stage and is associated with the Andropogons, Passing with these forms as they give place to the Boutelouas and being entirely absent in the older and more mesophytic prairie. In transitional stages from the bunch-grass open association to the less Xerophytic closed sod association, Agropyron .remains not infre- dtently in subcopious abundance as a relict of the earlier condition. The rootstock is here an efficient mode of propagation. The three grama grasses, Bouteloua hirsuta, B. oligostachya, and . curtipendula, which head out during the early days of July, enter upon anthesis almost simultaneously with the beginning of the “cond week of July, as does also the buffalo grass, Bulbilis dacty- loides. The Boutelouas are pioneer sod-formers, following only the buffalo 8rass, which as the pioneer sod-former encroaches upon the bunch-grasses, replacing them and preparing the way for the Boute- “Uas Which invariably follow closely. To the west, where the rainfall $ much less, Bulbilis is the prominent sod-former and is the fodder S488 of the great cattle ranges west of the Missouri. In our region 't occurs along the xerophytic exposures of the bluff line, and as a 280 BOTANICAL GAZETTE [ocroBER xerophytic relict along the crest of prairie knolls, where it mingles with the gramas as they advance upon the bunch-grass stage, yet usually as a secondary element among these sod-formers. In our area, however, it is lacking. Bouteloua hirsuta seems to be the pioneer of the gramas as they encroach upon Bulbilis, or upon the bunch-grasses where Bubbilis is absent, as is the case in our formation. It is in turn apparently C. Solidago rigida to the left; Helianthus scaberrimus to the right; admixture in the background. 1.—Serotinal aspect: Bouteloua curtipendula sod on upper slope; followed by B. oligostachya, which seems to occur more abundantly and to occupy the most prominent place of the sod-formers. sd quently it alone encroaches upon the bunch-grasses, B. hirsuta bene absent. Next comes B. curtipendula (fig. 1), which also contributes largely to the early prairie sod. In many places the Poa sod is al next to follow. The gramas are thus largely confined to the a decreasing in abundance downward, where they not infrequently rise to facial prominence. Contrary to the serotinal floral —_— the Boutelouas are of low stature, B. curtipendula alone rising above 1908] H{1ARVEY—PRAIRIE-GRASS FORMATION 281 45°, which however may frequently reach 60 to 80°, and is the only species which becomes at all conspicuous. These species as they enter the open bunch-grass association form mats, which fusing form sod, finally resulting in the replacement of the bunch-grasses. The gramas are all perennial by means of the eniarged rootstocks. : Coincident with the flowering of the grasses is that of Kuhnistera purpurea, which seems to precede that of its related species K. candida by only a few days. The purple Kuhnistera is from its distribution and structure more xerophytic than the white-flowered Species. The former occurs most abundantly on the higher slopes, decreasing in abundance downward ; while the latter reaches its maximum abundance on the lower slopes, decreasing in the number of individuals per unit area upward. Along middle slopes the abundance of the two species approaches equality. Its distribution seems clearly related to the chresard of these various habitats. CLEM- ENTS (’05, pp. 233) in light of these facts has suggested the mono- Phyletic origin of these two species from an ancestral form which became split up into purpurea and candida. under the influence of and adaptation to a low and high chresard, a xerophytic and meso- phytic habitat respectively, and has instituted experiments to test theory. In their respective positions of maximum abundance each may rise to dominance, which, however, never occurs in the plot under study; the advanced condition of the prairie seemingly pre- cludes such abundance in the closed association. However, they are the most conspicuous elements of the early part of the aspect. Their branching stalks rise 60 to 80°™ and are terminated by cylindrical Spikes (some 8 or 9°™ long) of white flowers in K. candida and (Some sem long) of violet flowers in K. purpurea. They are perennials from thick and deep roots. The seeds are immobile, which with the Perennial root accounts for their somewhat even distribution in the formation. : With the prairie clovers appear Eriocarpum spinulosum and godesmia juncea. Eriocarpum is perennial from a deep woody Foot, whose much-branched stems rise about 30 to 40°™, terminate nes 2 to 25 heads fringed with yellow rays and 2.5°™ in diameter. In all it is Very striking, but its rare occurrence along upper slopes and “tests precludes more than a minor influence upon the tone. It 282 BOTANICAL GAZETTE [ocroBER seems to demand only a low chresard, and upon more xerophytic crests than occur in our formation, where it holds its own, it appears copiously and not infrequently determines the tone of the open asso- ciation. The wind-distribution is facilitated by a copious pappus. Perhaps no plant of our formation has the remarkable degree of adaptability possessed by Lygodesmia juncea. The first plant to appear upon the bare exposed soil of bluffs, it persists into a well- formed mesophytic sod with even a marked abundance. It is to be reckoned as a xerophytic relict in our plot, occurring most abun- dantly along the crest, but at most only sparsely. It is a perennial from a heavy woody root, which interprets its persistence in the formation, and this with its reduced scalelike leaves contributes to its fitness as a pioneer xerophyte. The much-branched stems (45°™ high) end in solitary pink-rayed flowers, whose small size and ephemeral duration never render them florally conspicuous. Dis- tribution is very general and wide; the achenes are provided with a copious pappus. During the last days of the second week and early in the third week of July the prairie thistle, Carduus undulatus, enters upo? anthesis and florally characterizes this part of the aspect. Its densely white tomentose and much-branched stems rise some go°™ and gts nate in large (5°™ in diameter) solitary heads of numerous purplish flowers. It also assumes a gregarious habit, and patches occur here and there from base to crest of prairie slopes. Thus it is @ most conspicuous form, but reaches its maximum flowering only in early August. Wherever the prairie sod has been disturbed it becomes almost exclusive in its occupancy. It is a biennial of slightly mes phytic tendencies and so appeats more commonly on lower slopes: Its high fertility and copious pappus insure a wide distribution, easily explaining its very general occurrence. The last form to be added in the aspect is Lacinaria squarros’ which appears here and there upon upper slopes and crests. sh very xerophytic in nature, occupying a prominent place in the ea stages of the bluff line succession, and is in our plot to be consid 4 as arelict. It is not conspicuous and adds little to the tone, hes at this time rendered bizarre by several of the earlier forms ens their greatest floral display. Lacinaria is an erect (50%) peren™ 1908] HARVEY—PRAIRIE-GRASS FORMATION 283 herb from a tuberous structure, terminating in a spike bearing humerous heads of purplish flowers. The abundant plumose pappus assures a widespread distribution. Autumnal floral aspect No marked climatological change is to be noted in passing from the serotinal to the autumnal aspect, but simply one of gradually decreasing favorableness. Hence the latter has been set off partly for convenience of discussion, though it seems more or less distinctly characterized by definite floral activity; yet possibly it might be more accurately designated as late serotinal. Beginning in early August and marked by the estivation of such very conspicuous forms as Helianthus scaberrimus, Solidago rigida, and the bunch-grasses (Andropogon furcatus and A. scoparius), it extends into early October, When vegetative activity comes to an end. Its floral activity is terminated, however, in middle September by the flowering of Gentiana puberula and Solidago rigidiuscula, while florally the aspect is at its best during late August and early September, when the prairie is a sea of yellow from the Solidagos, mainly S. rigida, dotted here and there by the blue of Asters. Rising sentinel-like along higher slopes and crests are the rose-purple spikes of the blazing-stars, while on isolated knolls associations of Aster sericeus with their purplish flowers and White tomentose leaves relieve the sea of yellow. The bunch-grasses ay a very characteristic tone to the higher and more xerophytic nolls, In earlier aspects marked restriction of forms was noted, less “parent in the serotinal it is here scarcely evident. On the other and there is a marked identity of the controlling species on base, : lope, and crest, the entire formation presenting an unbroken and ° identical Covering, undoubtedly to be associated with the noticeable “quality of the chresard throughout these various situations. Eighteen of the twenty-two forms (82 per cent.) are composites, and all but one of these (Kuhnistera villosa) are wind-distributed. Like the prevernals the autumnals are pronouncedly xerophytic, ae into uncertain, that is unfavorable, ecological conditions, the Ormer at the initiation, the latter at the decline of floral activity. "st as prevernals have come to possess the spring period of not AUTUMNAL CLIMATOLOGY BOTANICAL GAZETTE [OCTOBER xomvaoavaa | over-favorable conditions, in the same degree asst | + | the autumnals claim possession of that less rama | t | suitable period during the closing days of Nam YEN | ‘3 | vegetative activity, and for similar reasons. presomp | BS Each group has been able on account of Cot es peculiar characteristics to work into and 3 | Pepe | dS occupy these periods unsuited for plants of B ate, eo less xerophytic tendencies, as their periods SOM ge of growth and reproduction fitted into these bea ig seasons of the year, extremes in each case, as where the great majority of forms could aes e not succeed. As floral activity is more is —| definitely restricted than vegetative, which is 8 ee largely accomplished in earlier periods, . 1S also evident that the problems of pollination ae ‘ and seed dissemination must have been no — | small factor in working out through selec- in a tion the floral restriction of these forms. a The following species extend over from '¢ | the serotinal aspect, but are rendered incon- a ern 8 spicuous by the overtopping layer of a few autumnal species: Verbena stricta, Carduus “a |= | undulatus, Ratibida columnaris, Meriolix es serrulata, Polygala alba, and Lygodesmia ‘tno | ™~ | juncea. They become less and less conspl wes Cuous as the period advances. 3 Ween As ruderals we may note Melilotus alba, f= | coming over from earlier aspects, Laciuca Sapte | canadensis, and Salsola tragus. ne a : * Conditions here are but the couetes "| and accentuation, during the early part ; weap : = aspect at least, of those of oe siege : Sere: G less pronounced toward early September; and | | + | toward the middle of the month ~ wane ‘S| gradually into those more settled — "| | tions of early fall in which maturation ® 1908] HARVEY—PRAIRIE-GRASS FORMATION 285 so largely accomplished. However, the climatological conditions (table) of this aspect bear to its floral activity a relation analogous. to that existing in the prevernal, and the forms here occurring seem in no less degree peculiarly adapted to the late seasonal conditions. In August the wind is dominantly from the south and east, but in early September begins to swing to the northeast quadrant, where it remains until the prevernal, then swinging round again to the south- east. The average daily rainfall (0.26°™) remains about the same as in the preceding aspect, though it falls on only 25 per cent. of the days, while in the serotinal it falls on 33 per cent. of the days. Relative humidity, sunshine per cent., and relative light intensity are notice- ably similar in these two aspects, while relative evaporation has decreased almost a third. In the fact that the hourly wind velocity has increased only a tenth, and in the 4° C. fall in the mean tempera- ture must be sought an explanation of this lowered evaporation. SPECIES OF THE AUTUMNAL FLORAL ASPECT Factes.—Andropogon furcatus,} A. scoparius.t PRINCIPAL SPECIES.—Solidago rigida,t Aster sericeus,} Helianthus scaberri- mus,t Sporobolus brevifolius.+ SECONDARY SPECIES.—Solidago rigidiuscula,t S. missouriensis, S. nemoralis, Ratibida columnaris,*} Aster multiflorus, Artemisia gnaphaloides,* Verbena Stricta,*} Carduus undulatus.* ; TERTIARY SPEcIES.—Aster oblongifolius, Solidago canadensis,t Kuhnia glutinosa, Lacinaria scariola, Nabalus asper, Lygodesmia juncea,* Polygala alba,* papposa, Grindelia squarrosa, Kuhnia eupatorioides, Lacinaria punc- tata, Gentiana puberula, Kuhnistera villosa, Meriolix serrulata.* UDERAL SPECIES.—Salsola tragus, Meliotus alba,* Lactuca canadensis.* * : . ase From earlier aspect. {Forming associations. During the early days of August four forms, destined later to be- Come very conspicuous, make their floral appearance in the following order: Solidago missouriensis, Helianthus scaberrimus, Solidago "emoralis, and S. rigida. SS. missouriensis, the first of the autumnal bloomers, occurs in subcopious abundance and most abundantly Eg the open association of the upper slopes and crests, where it is quite noticeable, though it never becomes a prominent feature of the tone because of its low stature and small panicles. It is distinctly Xerophytic, as is evident both by its structure and distribution, and, as 286 BOTANICAL GAZETTE [OCTOBER might be inferred, passes as the open formation gradually becomes closed, never being present in a compact sod at the base of the slope. Appearing with S. missouriensis comes H. scaberrimus. It occurs both more frequently and abundantly than the former and is dis- tinctly less xerophytic, reaching its greatest abundance upon middle and upper slopes. Its rigid, rough, and little-branched shoots, rising some 1.5™ and terminated by a spreading corymb bearing ‘ : ‘ sg . imus on Fic. 2.—Late serotinal aspect: Solidago rigida and Helianthus scaberrimus upper slope. few conspicuous heads (3 to 5°™ wide) with numerous yellow tay® make it a conspicuous element of the early autumnal aspect, oe : soon blends in the sea of yellow of Solidago rigida, which shortly comes on, completely dominating the floral tone. cameeest (fig. 2) rarely holds its own along the tension line where the Poa “t is encroaching, but with other open association forms yields to = advancement, though it occurs inclusively in the less compact S0°* higher up the slopes, in which places it frequently assumes 4 meas gregarious habit. The stiff sunflower is perennial by 4 thick 10 1908] HARVEY—PRAIRIE-GRASS FORMATION 287 stock. A very limited pappus of two to four'scalelike awns provides only a restricted distribution, easily accounting for its gregarious tendency. About a week or ten days later S. rigida begins its blooming, but only reaches its maximum about the last of the month, at this time solely characterizing the floral tone and maintaining a sea of yellow for some three weeks, when the tone begins to pale as fruiting advances and completely gives way during the third week of September, the bright-yellow floral tone yielding to the dull-green foliage. The stiff goldenrod occurs ubiquitously, but reaches its greatest abundance upon middle slopes, where it is frequently copious. The single stout stem (frequently several), from the perennial rootstock, rises some- what over a meter, terminating in a flat dense cyme bearing numerous yellow-rayed flowers, frequently 20 to 25°™ across, which with its abundance and frequency makes 5S. rigida the most striking and dominating in its floral tone of any single species of the formation. Following the latter species by only a few days S. nemoralis comes into bloom. Overtopped by and much less abundant than the former, It Never is conspicuous, though frequently it adds to the dominant yellow tone of the aspect. It reaches its greatest abundance on slopes, occasionally entering the open association of the crests, but is rarely included in the compact sod of lower slopes. The three goldenrods just noted are alike perennial from a thick- fned rootstock, with a tendency toward the formation of perennial basal Tosettes, and are widely wind-disseminated through the effi- ciency of the well-developed parachute. Almost coincident with the blooming of these four forms is that of the bunch-grasses, Andropogon furcatus and A. scoparius. Though these two grasses during the last two aspects have been vegetatively ©onspicuous upon the higher crests and most xerophytic slopes, where they Contribute the characteristic dull tone to the bunch-grass asso- eo, they flower only during the early part of August, thereby adding but little to their already established prominence. They are “companied by Sporobolus brevifolius, which occurs less abundantly, Dut like the beard-grasses assumes the bunch habit upon higher a and ridges. In these situations the Andropogons oe acial Tank, A. Surcatus ( fig. 3) being the taller and on account of its 288 BOTANICAL GAZETTE [OCTOBER invariable bunch habit far the more conspicuous. 4. scoparius (fig. 4) seems to form a very loose sod between the bunches of the former and extends lower down upon the slope, where in places it yields to the Boutelouas or rarely to Poa. In succession these forms seem to precede the Boutelouas. With a reduction of drainage and introduction of these sod-formers, the bunch-grasses yield, and in those portions of the prairie where succession has progressed most rven- __ Fic. 3.—Autumnal aspect: the bunch-grass, Andropogon jurcatus, with inte ng Spaces occupied by Bouteloua sod near crest of prairie knoll. rapidly, for example the northwestern exposure, the Andropogon and the “bunch-habit” are conditions of the past. With Agropyro” occidentale, the Andropogons and Sporobolus must be ranked as the pioneer grasses of the prairie, and as such hold a most important ecological relation in the structure and development of the formation. A. furcatus yields first, giving way to A. scoparius, which in pes assumes facial abundance and frequently persists in a somewhat anomalous way in the more mesophytic associations. These gr 1908] IITARVEY—PRAIRIE-GRASS FORMATION 289 are wind-distributed, to which end the hairy awned spikelets con- tribute. Being perennials from heavy resistant rootstocks, they are well adapted to the precarious pioneer position they occupy in the formation. Two composites, taking a minor place in the formation, must be mentioned. While belonging to the formation proper, they function mainly as ruderals. Dysodia papposa, which blooms at the beginning of the autumnal aspect and often earlier, occurs everywhere along : se Fo -rest Fix —Autumnal aspect: an Andropogon sod, mainly A. scoparius, upon cres kn¢ ill; Scattered individuals of Solidago, Helianthus, and Aster are presen roadsides and on w astes, where it attains its greatest size and abun- dane = od Frequently on the most xerophytic of prairie hills and bluffs » assumes a very marked prominence. In our area it occurs sub- ently along crests and ridges, in fact anywhere that the association ony be Open, though it is usually depauperate in such cases. The fetid Marigold is an annual, and its ubiquity finds cause in the ease and abunc dance of its dispersal through an efficient pappus, and in Re period of its germination falling at the time when the majority of forms have long since germinated and the formation is thinning off it ~~ e a hese farly annuals and prevernal and vernal perennials. Tot 290 BOTANICAL GAZETTE [OCTOBER reasons must further be added its high degree of adaptability for ger- minating under these less favorable serotinal conditions. The other form here included is Grindelia squarrosa, which occurs only sparsely and then almost entirely along lower slopes and fre- quently included in the Poa sods. On account of its scattered dis- tribution, the gum plant usually grows about so%™ high and branches much and more or less symmetrically, so that with its many heads of yellow ray-flowers it becomes quite noticeable in early September. Grindelia is a perennial from a heavy rootstock. The few awned achenes are inclosed in a glutinous head, consequently distribution is restricted, and correspondingly a gregarious tendency is to be noted. During the last two weeks of August several forms of secondary prominence in the floral tone progressively bloom. They are Solidago canadensis, Lacinaria scariosa, L. punctata, Artemisia gnaphaloides, Kuhnia glutinosa, and K. eupatorioides. Solidago canadensis, the most mesophytic of our goldenrods, seems to be confined exclusively to Poa sods in valleys and at the base of slopes. It is here gregatious in tendency, occurring in isolated patches or clumps. Also upee disturbed soil around coyote burrows it usually establishes itself in dense patches. It rises about a meter, with several shoots from the same large perennial rootstock, branches profusely, bearing so heads in dense panicles, and in all is most conspicuous along ee Grindelia at the base of slopes and in valleys. Its distribution : well-developed pappus is extensive, though its demands for the highes ecological conditions greatly restrict its establishment. The two button-snakeroots, Lacinaria scariosa and L. jough bloom about the beginning of the last week of August, - re ridges, and the prairies numerous short-peduncled heads of purplish flowers, DOT erect unbranched and usually solitary stem from a prom give these forms a most striking appearance. Copious assures a wide wind-distribution. punctala, * pappys 1908] HARVEY—PRAIRIE-GRASS FORMATION 291 The prairie mugwort, Artemisia gnaphaloides, is gregarious upon upper slopes. Here it forms dense patches, and these, on account of the white tomentosity of its stems and leaves, which are frequently so high, are conspicuous in the dominant tone of yellow. It bears to the autumnal quite the relation that the. Antennarias hold to the prevernal and vernal tone. Perennial from a tuber-like root, it is also xerophytic in tendency. In its pappate achenes and root- Propagation are found the causes of its gregarious habit. The closing days of August are marked by the estivation of the two false bonesets, Kuhnia eupatorioides and K. glutinosa. ‘They both occur but rarely and then mainly upon upper slopes and crests. They form little clumps (several shoots from the same perennial Toot) and are tall (so to 75°™) and much branched, but on account of their small few-flowered heads of creamy-white color and their only occasional frequence, they never attain any prominence. However, they become much more noticeable when the rich white pappus Spreads in maturatian, during the second week of September. K. eupatorioides is more mesophytic and so occurs more frequently over the formation. XK. glutinosa, however, is pronouncedly xerophytic, and is restricted in its distribution to the open association along crests and higher slopes. The abundant barbulate pappus assures prolific invasion, though establishment seems to be very limited, doubtless rie to the apparently low degree of adaptability possessed by these orms, The Kuhnias are accompanied by Nabalus asper, which is restricted to lower slopes, is of rare occurrence and thus always a nunor element. ‘Though it is of the upper layer and bears numerous heads of pale-yellow flowers, it blends into inconspicuousness in the seneral tone, Itisa perennial from a tuberous root. A well-devel- Ped parachute insures wide dissemination, but high ecological de- mands preclude more than a rare establishment upon the prairie. boii mi early days of September are well marked by the blooming of orms which occasionally attain more or less restricted promi- _ Mnee: Aster sericeus , A. multiflorus, A. oblongifolius, and Kuhnistera — *y are all of evident xerophytic tendencies and — th Y upon the upper slopes and crests. Appearing at a time when fre Is an pparent decline in the dominance of the earlier tone, and 292 BOTANICAL.GAZETTE [OCTOBER occurring in the open association, the Asters become quite noticeable though they are all of a lower layer than S. rigida. The silky Aster, A. sericeus, usually of low abundance and general occurrence, fre- quently becomes copious on bunch-grass knolls, there forming very distinct associations. Rising some 50°", with numerous spreading branches terminating in prominent heads (2 to 3°™ in diameter) with numerous violet rays, and bearing abundant leaves which are densely covered above and below with a silvery-white silky pubescence, this Aster is always a conspicuous element of the middle and late autumnal aspect. Its achenes are equipped with a medium pappus. It is a perennial from a thickened rootstock. The two other Asters are similar in frequency and abundance mM A. sericeus, but never attain its prominence. Of these A: oblongt- folius always occurs with A. sericeus in the open association. With us it always remains depauperate. Seldom more than 30% high, it is ever inconspicuous, though its bluish rays make it noticeable at short range, since it is usually overshadowed by A. sericeus. It ” a perennial and is wind-distributed; a copious pappus serves to bring about a general invasion, which, as in the other Asters, seems 10 be coupled with a high percentage of establishment, especially 1 ee open xerophytic associations of the formation. The dense-flowered aster, A. multiflorus, occurs perhaps more frequently but less abun- dantly than the former, and is similarly a xerophyte of the open wae ciation, in which situations it never reaches other than 4 redue h stature. However, its bushy spreading branches, thickly ager om numerous small white heads, invariably make it more eeu than A. oblongifolius, particularly when it occurs in pa px tet seems to work down upon the lower slopes, here attaining . sa stature and abundance as well as a greater prominence in anthies All the Asters are perennial from rootstocks and form small Tosettes, and are wind-disseminated. - 1 from & The hairy prairie clover, Kuhnistera villosa, is a perennial ched deep tuberous ‘root. Densely silky pubescent, abundantly bran 5) of and terminating in cylindrical clustered spikes (3 © és _ -cted Tos¢-purplish flowers, it is in itself quite conspicuous, but its sos the frequency and rare abundance make it rarely a tonal com formation. In the bunch-grass formation it becomes, W! 1908] HTARVEY—PRAIRIE-GRASS FORMATION 293 canescens, more abundant but never controlling. It is distinctly xerophytic, and while largely of the open association, it may work down slopes into more favorable habitats. ; During the middle days of September the last two forms of the prairie-grass association present their flowers, Gentiana puberula blooming a few days before Solidago rigidiuscula, the last form to bloom. The downy gentian occurs rarely and is largely restricted to middle and lower slopes, rarely if ever occurring along the xerophytic crests and ridges. Its terminal group of few large light-blue flowers are rendered unimportant as the plant is of short stature (30 to 40°) and so hidden. It is perennial from thickened roots, and wind- distributed, the seeds being widely winged. Its rarity therefore lies no doubt in its high ecological requirements, being somewhat mesophytic in its nature. The last form of the prairie to bloom is Solidago rigidiuscula. Flowering as it does when S. rigida is passing into fruit, of copious abundance and high frequency upon upper slopes, occurring gre- gariously at times with several stalks (5 to 15) arising from the same perennial root, it is rightly named the “showy” goldenrod. It per- “sts nearly to the middle of October, and is one of the last forms to Pass into fruit, though accompanying it are the later flowers of Merio- lx, Ratibida, Carduus, Polygala, and Lacinaria. It is widely wind- ‘persed and establishment is quite general. Post-floral aspect By the second or third week in October the prairie forms of the ‘utumnal floral aspect have all passed into seed, and the gorgeous Yellow of Solidago rigida has given way to the somber brown of frosted leaves and stalks. While seed maturation and distribution in species of earlier aspects have been in progress during the subsequent aspects, i Post-floral aspect, extending up into late November, is particu- rly characterized by this phase of plant life, yet dispersal may and does Continue, but in a much more limited degree even during the “inter season. The little fall of snow leaves the prairie bare the Seater part of the winter, its tone being in no way modified; the oer etumnal appearance remains to characterize the prairie through- non-flowering period, and, as has already been pointed out, 2904 BOTANICAL GAZETTE [OCTOBER extends up to and even dominates the prevernal and vernal floral aspects. Summary of the structure of the formation The formation is strictly of the prairie-grass type, its facies being determined mainly by six species: Bouteloua oligostachya, B. curti- pendula, B. hirsuta, Koeleria cristata, Andropogon furcatus, and A. scoparius, to which must be added Poa pratensis in valleys and on lower slopes. The Andropogons are the main sod-formers of crests and ridges, while the Boutelouas characterize the higher slopes, working up to the crest and ridges. Koeleria seems to be more closely associated with the Boutelouas, occurring on middle slopes mainly. With these are associated three sedges and seven other grasses, which are all important as cooperating sod-formers, some of them ranking as primary species in the formation. We may mention Carex pennsylvanica, C. festucacea, and Sporobolus brevifolius as perhaps the more important of these. It is to be remarked that the sedges are all pre-estival, while the grasses are all estival or pee estival in their floral activity; the first facies to bloom is Koeleria 10 the estival aspect, while the Boutelouas are serotinal and the Andro- pogons autumnal. Upon this facial background of grasses there progressively appe™ several conspicuous flowered forms of primary importance, which with numerous secondary and tertiary species serve to impart 4 bizarre aspect to the formation when considered as @ whole and 4 : x ‘ ‘ z . ns 0 kaleidoscopic shift with seasonal succession. In passing it 1s oe note that species primary in their own floral aspect may Lagogies y consider secondary or tertiary importance when the formation is con ae as a unit. Among these primary species we may note the ubiqu Aniennaria campestris; the Spesias and Sisyrinchium ©! seibid slopes; Amorpha canescens upon upper slopes and sauce pre T , upon lower, and Verbena and Erigeron ramosus upon upper » se Symphoricarpus in valleys and on lowest slopes; the eae K. upon slopes, K. purpurea occupying the upper slopes, ps ee candida extends downward upon lower slopes; Solidago rigida Helianthus scaberrimus of great frequency and abundance; and Aster sericeus upon isolated knolls. 1908] HARVEY—PRAIRIE-GRASS FORMATION 295 Among the more important of the secondary species may be men- tioned Viola pedatifida and Oxalis violacea of middle and lower slopes; Meriolix serrulata of higher slopes; the Lithospermums of the more xerophytic portions of the formation; Plantago Purshii of middle slopes; Linum rigidum in the open association; Potentilla Hippiana, Carduus wndulatus, and Polygala alba, which occur on middle and lower slopes; Solidago rigidiuscula and S. nemoralis upon lower and middle slopes, and S. missouriensis upon upper slopes mainly; and finally Aster multiflorus and A. oblongifolia. Considering the ground association, the open association prevails over ridges and crests and extends down somewhat on slopes, passing gradually through a transitional condition into the closed association which occupies the valleys, depressions, and base of slopes, working always up or outward, displacing the open association. Poa pra- fensis establishes the most dense association, but the Boutelouas, Koeleria, and Festuca exert perhaps a more extensive influence in reducing the open association. In this connection it should be noted that the Andropogons are par excellence the pioneers, breaking up the Xerophytic open association upon the highest and most xerophytic crests, preparing the way for the Boutelouas. It may be possible that in some cases the Andropogon bunch-grass stage was not the Ploneer society, but that on account of more favorable soil moisture Conditions, largely a question of drainage, the Boutelouas were the Initial sod-formers. However, upon crests and ridges of excessive drainage the Andropogons have invariably preceded the Boutelouas and Koeleria. Occurring rarely in the open association is an unde- termined xerophytic moss, while two species of the Basidiomycetes have been noted in the more mesophytic portions of the formation. The enumeration of species includes go forms belonging to the formation proper and some 18 ruderals which work into‘the forma- tion from the contiguous cultivated regions. The most abundant and prominent of the latter are Cassia chamaecrista, two species of Melilotus, Hordeum jubatum on lower slopes and moist soil; Panicum ‘apillare, Verbena bracteosa, and Amaranthus graecizans of the more °PeN associations; Onagra biennis of general occurrence; Salsola of the open association; and finally Lepidium virginicum, which not infrequently becomes quite abundant in the open association of 296 BOTANICAL GAZETTE [OCTOBER higher slopes. These ruderals are characteristically confined to marginal invasion, though they are frequently found wherever the Open association makes possible their establishment. Onagra, how- ever, is able to establish itself in the closed formation, as is Pofentilla mons peliensis. Hordeum especially makes advance where some artificial agency has destroyed the equilibrium in rich moist stations; frequently in such cases it assumes even facial rank. The 90 prairie elements proper have a most interesting taxonomic distribution. The composites with 29 species (32.2 per cent.) form the dominating family, comprising nearly a third of the total forms. The Gramineae number 15 species (16.6 per cent.), and though not leading in species they rank first in number of individuals. The third important family is the Leguminosae with 11 species (12-2 per cent.). Thus these three families provide 61 per cent. of the prairie elements and perhaps over go per cent. of the individuals. The remaining 35 species (39 per cent.) are conspicuous on account of their diverse affinities, belonging as they do to 22 different families, 14 of which have only a single representative in the formation. The families are as follows: Borraginaceae (4), Ranunculaceae (3); Cyperaceae (3), Onagraceae (3), Scrophulariaceae (2), Linaceae (2), Rosaceae (2), Oxalidaceae (2); and the following with one specie each: Nyctaginaceae, Cruciferae, Umbelliferae, Iridaceae, Violaceae, Euphorbiaceae, Caprifoliaceae, Solanaceae, Labiatae, Plantagina ceae, Gentianaceae, Verbenaceae, and Polygalaceae. The life conditions of the formation are by no means equable, and in this relation it is significant to record that only 11 per ? ¥ of the species are annual, the majority of which produce abundant seeds and are provided with efficient means of distribution and occur mainly in the xerophytic open associations. Of the remaining 89 per cent. which are perennials, 96.2 per cent. are geophytic; —_ Symphoricarpus, and Amorpha alone are woody. as In a region characterized by strong prevailing winds 1t !s to : noted that a high percentage of the species is wind-distribu : An analysis of this point shows that about go per cent. are so een inated, some 55 per cent. showing especial facilities to this €” The great range of specific forms and their marked frequency si the formation finds an explanation in this permobility eee 1908] HARVEY—PRAIRIE-GRASS FORMATION 297 ductive organs possessed by such a large percentage of its com- ponents, As to pollination, 20 per cent. of the forms are wind-pollinated, while 80 per cent. have their pollen transferred by insects, the sedges and grasses comprising the former group. Conclusions 1. The formation is a part of the Niobrara Prairie Region of CLEMENTs. In composition it is transitional. More truly a part of the prairie to the west, yet it contains several pioneer forms from the more mesophytic prairies to the south and east. 2. These two groups of elements during post-glacial migration have entered along two distinct lines of advance. The former mi- grated northwestward from a southwestern center of dispersal, while the latter followed a northwestern track up the Mississippi and Missouri valleys. 3- The prairie is pre-glacial in origin and is descended from the climatic prairie of Tertiary times, which arose in response to reduced Precipitation caused by the upheaval of the Rocky Mountains at the Close of the Cretaceous. 4. The climate is typically a prairie climate. A relatively dry testing season from October to March, in which only 16 per cent. (10. 4°") of the total precipitation falls, and a moist growing season ftom March to September, in which 83 per cent. (49-31°™) of the Precipitation is distributed over sixty days, with 25 per cent. concentrated in April and May, insures a prairie formation. On the other hand, the annual low relative humidity, the dry and high winter winds accompanying high temperature, low winter rainfall, absence of a snow blanket, and the hot, dry summer of low precipi- ‘ation are inimical to tree growth. 5- The absence of trees upon the prairie is primarily to be explained ‘pon historical lines. The prairie was climatically determined and successfully and successively maintains itself against tree invasion m the edaphically determined arboreal fringes along flood plains and in ravines, 6. The northern slopes are the last to recover from winter, but are Most Mesophytic. It is up these slopes that the Poa sod and the 298 BOTANICAL GAZETTE [ocToBER | shrub association of Symphoricarpus and later Rhus glabra advance, preparing the way for the bur oak-slippery elm association, which likewise makes its greatest progress up these slopes from ravines and flood plains. 7. The floral activity of the formation may be approximately recorded in the following five aspects, set off by marked climatic and floral changes: prevernal, April 1 to April 25, 6 species; vernal, May 3 to May 31, 28 species; estival, June 1 to July 7, 21 species, serotinal, July 7 to August 7, 13 species; autumnal, August 7 1 September 21, 22 species. 3 8. The prairie elements show a marked grouping into vertical layers, which correspond approximately with the floral ese Overtopped by the autumnal layer the sub-layers are successive y those of the serotinal, estival, vernal, and prevernal. g. There isa marked distinction in the chresard of base, ee and crest in the prevernal, which becomes less marked in the sequent aspects, approaching equality in the autumnal. As a resus the floral covering shows a corresponding difference upon base, i and crest in earlier aspects; the influence of position grad zs declines, the floral covering presenting a striking similarity overt entire formation in the autumnal. THE UNIVERSITY oF CHICAGO BRIEFER ARTICLES A PARASITIC ALGA, RHODOCHYTRIUM SPILANTHIDIS LAGERHEIM, IN NORTH AMERICA During February, 1908, Dr. F. L. Stevens, of the North Carolina Agricultural College, sent me a few dried leaves of the common ragweed, Ambrosia artemisiaefolia, which contained a very interesting parasite. Externally it suggested the appearance of a Synchytrium, because of the humerous minute red dots distributed beneath the surface on the petioles and veins of the leaf and on the stem, although there was no gall forma- tion similar to that caused by species of the Synchytriaceae. A section of the host, however, showed clearly that it was very different from any of the members of this family. Maceration or teasing of the host tissue revealed the presence of a mycelium, and the crowded condition of the fruit bodies suggested the genus Cladochytrium. Further study proved, however, that it was a unique type, very different from members of this genus. Since the material received was dead, it was impossible to obtain the zoospores, and Dr. STEVENS kindly promised to have fresh material sent me at stated times during the summer. Beginning in the month of June, material was collected by Mr. J. G. HALL, assistant in botany at the North Carolina Agricultural College, and mailed once a week. Entire plants were collected, the roots were washed, and then packed mostly in pasteboard boxes with wet sphagnum. In this way they reached me in two or three days after shipment in very good condi- hon, so that some of the parasitized ragweed plants were transplanted in the open and others in pots where they continued to grow. From a study of this material I have been able to obtain the zoospores from the temporary zoosporangia and to work out certain stages in the life-history of the parasite. While searching the literature for unique forms of plant parasites, I discovered that this plant had been described fen years ago. This remarkable parasite is Rhodochytrium spilanthidis Lagerheim.* It was first discovered by LAGERHEIM in 1889 near Quito, Ecuador, and later Was observed by him in other provinces of Ecuador. In Ecuador it ‘S Parasitic on the stems and leaves of a species of Spilanthes, one of the ; LAcERHEM, G. DE, Rhodochytri nov. gen., eine Uebergangsform von den Protococcaceen zu den Chcuideeen: ak its 51:43-53- pl. 2. 1893. 299] [Botanical Gazette, vol. 46 300 BOTANICAL GAZETTE [OCTOBER Compositae. LAGERHEI searched diligently but in vain to find it on other genera of plants. Its discovery in North Carolina, therefore, is a matter of considerable interest, not only because it naturally occurs on a different host, but because of its existence in the north temperate zone as well as the temperate section (mountain regions) of the tropics. Its North American host, Ambrosia artemisiaejolia, is not very distantly related to the South American host S>ilanthes, the former belonging to the section Helian- theae-Ambrosiinae, while the latter belongs to the section Heliantheae-Ver- besininae.? The question of its distribution becomes an interesting one, as to whether it is distributed over the intervening territory of Mexico, Central America, Panama, and other tropical countries; or whether it has been by chance imported from one country to the other through commerce; or finally whether ages ago, when the territory from the southern United States to Ecuador may have had a different climate, the parasite might have existed throughout this range, but now is serarated by a tropical belt. I hore that collectors may be on the lookout for it in other parts of the United States and also in the intervening tropical region. I should be very glad to receive material in order to obtain further information as to its distribution. The form of the plant may be briefly described as follows: When mature it may be likenéd to a miniature flask with a long slender tortuous neck; while from the base, or from the sides or both, rhizoid-like process€s * extend, which branch profusely in a very peculiar and characteristic man- ner. In general its form might be likened to that of a giant Entophlyctis, on€ of the chytridiaceous endobiotic parasites of the algae. In its development the zoospore, at rest on the epidermis, germinates, the germ ag enters between the cells and moves on toward a fibrovascular bundle Where it branches, the branches making their way between the cells parallel with the bundles, so that on the stem the mycelium extends both upw and downward. On the leaves the parasite is also confined to the vascular bundles. The entire mycelium at certain stages of development is crowde with a reddish-yellow oil, which at maturity of the temporary zoosporang! or of the resting sporangia, is withdrawn along with the protoplasm aie the main body of the plant. The zoosvorangium rests within or i fibrovascular bundle and arises by a swelling of the mycelium at the yao where the entering germ tube branches. The sporangia vary greatly shape, They are oval, subtriangular, elli>tical, etc., and vary from 5° 7 in diameter (the smaller ones on the leaf) to 200-300 #. The terminal mycelium is provided with numerous short haustoria, many of which . applied very closely to the spiral ducts. In the resting sporangia itt ? See HorrMan in ENGLER AND Prantt, Pflanzenfamilien 45: 220 and at 1908] BRIEFER ARTICLES 301 of the mycelium next to the fruit bodies becomes very thick, also that of the entering germ-tube, while the wall of the zoospore in all of the plants remains as a small trumpet-shaped expansion of the end of the tube on the surface of the host. Starch grains are abundant in the larger portions of the mycelium and in the sporangia. The wall of the resting sporangium consists of three layers, the inner being laid down by the protoplasm after its accumulation in the main part of the plant body, and is thus not con- tinuous with the mycelium which, however, usually becomes plugged after the withdrawal of the protoplasm. The walls of the resting sporangia are yellow at maturity, while the content is dark red. The temporary zoosporangia have a thinner wall than that of the resting sporangia, and at maturity develop a stout exit tube, the end of which opens by a pore, the margin of which grows inward by invagination. The 200spores when swimming rapidly are elliptical in form, with the red oil in minute drops at the forward end, where are the two cilia. As they slow down they become rounded and are 8-10 p in diameter. LAGERHEIM considered this plant to be an alga devoid of chlorophyll, though Linpavs3 says that on account of the lack of chlorophyll it cannot be classed with the algae. The alga to which Rhodochytrium appears most closely related, according to LacERHEIM, is Phyllobium, discovered by Kiess+ (Phyllo- bium dimorphum in leaves of Lysimachia nummularia and more rarely in Ajuga repians, Chlora serotina, and Erythraea centaurium; Phyllobium mcertum in dead Carex leaves). It is an intercellular parasite and P. dimorphum has also a definite relation to the vascular bundles. In this Species the enlarged portion of the plant body contains chlorophyll in the Protoplasm, as well as a reddish-yellow oil and starch. The branched thizoid processes are devoid of chlorophyll. Resting spores only are known. They are packed with the reddish-yellow or orange-red oil and Starch and possess a thick wall with several layers. The zoospores are biciliate. A more extended paper is in preparation, dealing fully with the question of development, morphology, physiology, and cytology of this remarkable Plant. This note is published in the hope that it will stimulate a searc ‘pon the ragweed and other possible hosts for this parasite, and I should Consider jt a great favor to receive material from different observers in ase it is found.— Gro. F. ATKINSON, Cornell University. * ENcLER an PRatL, Pflanzenfamilien 1°*#:528. 1900. as = G., Beitrige zur Kenntniss niederer Algen formen. Bot. Zeit. 39: 249- ? 295-272, 281-290, 297-308, 313-319, 329-336. pls. 3, 4. 1881. 302 BOTANICAL GAZETTE [OcTOBER NOTE ON BALANCED SOLUTIONS Some statements by Professor W. J. V. OstERHOUT in the February number (p. 125) of the BoranicaL GAzeETTE in reference to balanced solutions require correction. 1. Balanced solutions, which are not complete culture solutions, were constructed and described? by me in 1892. 2. A balanced solution, which is at the same time a complete culture solution, is the solution of Knop, proposed about sixty years ago. The “confusion” supposed by OsTERHOUT does not exist in this particular. 3. OSTERHOUT claims to have discovered an antagonistic action of potassium to magnesium. But I observed long ago that secondary potas- sium phosphate can retard the poisonous action of magnesium sulfate;* and also that another potassium salt—the monopotassium phosphate— accelerates the poisonous action of magnesium sulfate. 4. OSTERHOUT claims to have discovered a poisonous action of pote: sium salts. But I have observed Spirogyra alive for three weeks m @ 0.3 per cent. solution of KCl?, and alive for ten weeks in a 0.1 per oe solution. In a 0.3 percent. solution of K,SO,, the alga cells remained alive for over four weeks. The definition of OsteRHouT, therefore, must be restricted to certain conditions. I have deprived young barley plants 9 endosperm, and kept them alive in 300° of a 0.5 per cent. solution of K,SO, for over two months. Is it possible that here the small amount of magnesia in the plants has counteracted the “poisonous” action of the large amount of potassium salt ? : 5. A pupil of OsterHouT claimed recently to have discovered a polson- ous action of calcium salts. This is not in accordance with my observa- tion that Spirogyra can remain alive for over sixty days in a I as = solution of KCl. “Poisonous,” however, is a relative and elastic set The favorable effect of lime upon the development of root hairs, mention by that author, I observed long ago.3 6. I cannot agree with the opinion that the antagonistic potassium to magnesium has the same cause as that of calcium to sium. I suggested an explanation of the poisonous action of eure sulfate, and also of the antagonistic action of calcium salts, in 1892. * Flora 75: 382. 1892. ; Bull. Coll. ? Loew, O., anp Aso, K., On physiologically balanced solutions. é Agric. Tokyo 7:no. 3. 1907. 3 Flora 75:384. 1892; Bull. Bureau Pl. Industry, no. 45, PP- 5% 5? ion relation of magne- explanation + Flora 75:376, 383. 1892; Bull. Bureau Pl. Industry, no. 45- My without ? , . - * t has been adopted by one author, from somewhat similar observations, bu giving credit. 1908] BRIEFER ARTICLES 303 Since my views hold good also for the animal body, it gave me great satisfaction when MEttTzeErR and AveErS published recently a series of wonderful experiments on the living animal, from which they inferred that “the continuation of the studies led up finally to the discovery that calcium is rather the strongest antagonist to the inhibitory effects of magne- sum.” ‘This is exactly what I have claimed for plants!—Oscar Loew, Munich, Germany. FORMATION OF ADVENTITIOUS ROOTS IN THE UMBRELLA CHINA TREE (WITH TWO FIGURES) A curious case of ‘‘self-eating”’ may occasionally be found in hollow and decaying trunks of the umbrella China tree (Melia Azedarach umbra- Hic. x Fic. 2 ead @). During a heavy storm in July, 1908, several large trees of this ind Were blown down, the breaks occurring at the point w here the main I ‘Amer, Jour. Physiol. 21: 403. May 1908. Communication from the Rockefeller nstitute, Saige York. These brilliant iieeatiputions obscure all others made wit Such salts on animals. 304 BOTANICAL GAZETTE [OCTOBER trunk had been sawed off many years previously. Adventitious sprouts had grown out at the top and around the edges of the stump, and had formed a complete circle of stout limbs. In time these limbs will completely heal over the cut surface so as almost to obliterate the wound. The woo of the stump soon decays, however, and into this decaying mass there Project dense mats of adventitious roots which spring from the point of origin of the limbs. These roots descend through the decaying materials and often, upon reaching the harder, less decayed wood of the lower part of the stump, turn sharply back and grow upward even to the point of origin. Fine fibrous roots may be found working down into the harder Portions. Fig. 1 shows a portion of a tree which had broken off about six feet from the ground ; the roots shown are about two feet long. Fig. 2 shows a limb that had broken off from a stump. The bent roots in the center were originally so sharply bent as to bring the parts parallel, but were separated for photographing. It will also be seen from this photo- graph that adventitious roots may arise from any part of the inner wall of the decaying stump.—O. M. BALL, College Station, Texas. CURRENT LITERATURE BOOK REVIEWS The Bonn Textbook A new English edition of this well-known textbook may be made the occa- sion to refer to the contrast between German and American instruction in botany. It is perhaps safe to say that the Bonn textbook is the most extensively used text in Germany, and that in its English translation it dominates in American colleges. And yet, from the American standpoint it is more a book of reference than a textbook in the usual sense. Its organization and its demands are pecu- liar to the German mind and the German system of education. To divide a book into “general botany” and “special botany,” and especially to discover that these titles are arbitrary rather than significant, suggest some rigid, old- fashioned curriculum rather than a logical presentation. ‘General botany” that Includes no contact with the great groups, no basis for the evolution of the Plant kingdom, no large conception of any kind, is surely a misnomer. It is made to include “morphology,” a morphology that does not consider the develop- ment of groups, which means a long-abandoned morphology. Then this morphology (170 pp.) is divided into “external morphology” and “‘internal mor- P hology” (subtitle ‘histology and morphology”). The ‘external morphology” 'S teally the old type, when ‘flowering plants” furnished almost the only material of botany. It is not a question as to the accuracy of the facts, or to their impor- lance, but simply a question of organization. Such an organization does not oo the development of botanical science today, and it does harm if it fads the student to a misconception of the content of the great divisions of nag Nor is the organization and presentation of this so-called “morphology” * only antique flavor; for when one finds in the textbook sections on the “meta- Morphosis”” of shoots, of leaves, of roots, he wonders why this point of view has never been changed. cxecnt® Section on physiology (153 pp.) by the late Dr. Nout is in the main an cellent and well-ordered presentation of the facts, though here and there it aes been revised to date. Thus, the fable of the ant plants still appears all its frills (p. 235), and the physics of absorption is decidedly antique. 7 eat of this section most open to criticism is the remarkably vitalistic solely : ch author. To say that “any attempt to explain vital ape "the Sei tae and physical laws could only be induced by a false conceptio Thing oe SEURCER, E., Nott, F., ScHENCK, H., KARSTEN, G., A text-book of botany. - — English edition, revised with the eighth German edition, by W. H. Lane. +746. figs. 779. London: Macmillan & Co. 1908. 395 306 BOTANICAL GAZETTE [OCTOBER of their real significance and must lead to fruitless results,” is to decry all inves- tigation; for that is just what every physiologist in the twentieth century is doing. That “physical attributes . . . . can never explain qualities like nutri- tion” is a bold prophecy and a most discouraging one, though we be yet far from that goal. ‘Strictly physical and chemical processes” are contrasted with “strictly vital” ones, in that with the latter it ‘becomes impossible to predict what effect a particular cause will produce.” True; but only because we do not know enough. Not disclaims “vital force” in terms, but constantly writes as though it were a necessary assumption. The second part, entitled ‘‘Special botany,” is doubtless the part of the book that gives it its deserved rank among texts. It is really and dominantly modern morphology as to facts, but not in spirit. It is a well-selected thesaurus of mor- phological information, in using which one feels a certain measure of confidence, and this is what has made the book indispensable. But the controlling spirit of morphology is lacking, because there is no conception of continuity in the p kingdom. To an American teacher of botany this means that the facts are dumped down in piles, with no attempt to use them in the organization of a structure. It is good science, but poor teaching; and that seems to be the general method of instruction in German universities. ‘This is not intended as a critiais®, but merely as the statement of a distinction. “Special botany” comprises ‘‘Crytogams” and “‘Phanerogamia.” incongruous forms of the two names, and the perpetuation of the old notion that a great chasm is fixed between cryptogams and seed-plants. Through the ctyP- ne breathes, Note the are 170 pages dealing with the details of the classification of “Monocotylae” ae ““Dicotylae.” And here comes a demand on the German student that ap = American teacher with amazement. It simply means that students 1m supe and pharmacy are driven into these courses in botany; that it is supposed eg a good for them to digest this encyclopedic information about groups tne that the German professor of botany cannot dispense with the fees of students; and that all German textbooks on botany must contain this dreary waste of pages. We would suggest that this German educationa should not appear in the English translations, for it needlessly enlarges the for American use.—J. M. C. and C. R. B. book Plant anatomy Under this title Srevens has written a book? which deals with the develo?” ment and functions of plant tissues. Structure and function are i pro the and rightly, that there is no anatomical part of the book as distinct of the develop- ment and functions of the tissues, and handbook of micro-technic * STEVENS, WiLLIaM CHAsE, Plant anatomy, from the —— it ga AEE 136. Philadelphia: P. Blakiston’s Son & Co. 1907. $2. 7 1908] CURRENT LITERATURE 307 physiological. In a review, however, the description of structures and of their functions may be mentioned separately. In the days of the Sacn’s régime, introduced into this country by BEssEy, the detailed study of tissues was a prominent feature of botanical instruction. It was gradually eliminated because of the growing demand for details that were thought to be significant in the evolutionary history of plants. A fact without a Suggestive and large meaning came to be regarded as not worth while in elemen- lary teaching. Doubtless this elimination of the study of tissues as such went ‘oo far, and a generation of botanists has been developed with too little knowl- edge of this kind. Then came the wonderful modern revival of anatomy so far as the vascular system is concerned, but this revival had to do with the evolu- tion of vascular plants. SrEvENs has carried us back again into the old atmos- phere of tissues, but he has sought to avoid the old deadness of the subject by relating tissues to their functions. ‘The spirit that animates the “skeleton,” therefore, is physiological and ecological, and not the conception of evolution. The tissues are well described and illustrated, for STEVENS is an excellent teacher; and the text and drawings have been prepared in large measure directly from Material under observation. It is to be regretted, however, that no trace of the modern vascular anatomy appears. For example, the remarkable development of knowledge in reference to the relation between the vascular anatomy of mono-. cotyledons and dicotyledons would seem to have deserved mention. It may be claimed that relationship is not being considered, but this particular relationship has to do with previous misconceptions as to the actual structure of the vascular anatomy of monocotyledons. Remembering that this is a book on physiological anatomy and not a text- book of plant physiology, we may properly commend the presentation of such Pics as come within its scope. ‘That is far less comprehensive than the well- known Work of HaBeRLANDT, and the matter is far more elementary. The topics presented are chiefly those of entry and exit of materials, their movement in the plant body, and the processes of nutrition in the broadest sense. These are Presented simply, clearly, and in the main accurately. Clever diagrams have been freely used, and they fulfil well the author’s design of rendering more real ~ Processes described. If they have any fault it is perhaps in tending to make ~onceptions too formal. Growth movement and the extensive phenomena of "™mitability do not come within the author’s plan. eg € unfortunate conception, embodied in chapter headings, and wrought . the text, is that of “circulation” of water and foods in Spsinrsaaeed — This idea dies hard, and we are sorry it has a new lease of life in this The final chapters deal with the preparation of sections, use of the microscope, easy and processes, the michrochemistry of plant products (not always reli- ‘it oe "3 detection of adulterations (too short to be really useful).—J. M. C. 308 BOTANICAL GAZETTE [OCTOBER Bokorny’s Textbook _ Boxorny has published a textbook of botany? that meets the official require- ments for instruction in the Oberrealschulen and Realschulen of Bavaria. It appears in two parts and is thoroughly well printed and illustrated. The author- ship of the book is a guarantee of its accuracy, and therefore the chief interest lies in discovering the kind of botanical material that is thought appropriate for the German student who is approximately the equivalent of our students from the third year of high school through the second year of college. In short, the purpose of the book would be about the same as that of most of our texts for high schools, which are announced for high schools, but are really suitable for colleges. It is evident at first glance that the demand is for a general survey of the whole domain of botany. The first section (145 pp.) deals with “flowering plants,” and is introduced by studies of common garden forms, the first contact being with rape and the various cabbage types. In this way a knowledge of the gross morphology of angiosperms is developed; to which is appended what would seem to be a few useless pages of cryptogams. The second section (15 pp) deals with “inner morphology,”’ which is explained to be “plant anatomy” or “histology.” Yeast, pine needles, starch grains, chloroplasts, growing points, vascular elements, root-hairs, etc., form the usual débris under such a captoD. The third section (197 pp.) is a presentation of the classification of the plant kingdom, that amazing impossibility that rides every German text like the io man of the sea. It is like inserting a dictionary of the language into the midst of a course on literature. We presume that the German boy must submit to it, but we wonder at his docility. This closes the first volume The second volume includes four sections. The first (20 pp-) really the second . the € general structure of the book would not be so very diff : of me corresponding American texts, were the 200 pages of classification boat oe MINOR NOTICES ; se asec Bibliographia Linnaeana.—This work+ represents the most complete bibliog raphy of the numerous Linnaean publications ever compiled. The pe works of Liynagus and the publications of other authors directly r elating = oer chronologically, beginning with the Dissertatio botanica de _5 Boxorny, Tu., Lehrbuch der Botanik fir Oberrealschulen und ie Teil I, pp. vit 366, M4. Teil II, pp. 233, M3. Leipzig: Wilhelm lage * Hurts, J. M., Bibliographia Linnaeana: Matériaux pour servir 4 3 - — Linnéenne. Partie 1, Livrasion 1, 8vo. pp. 170. pls. 1-3, 5-9 TF a, ——* PUniversité, C. J. Lundstrém. Berlin: R. Friedlander & Sohn. 1997 1908] CURRENT IITERATURE 309 Sceptrum Carolinum dicta, quam * * * praeside Laurentio Robergio * * * ven- tilandam sistit auctor Johannes Olavus Rudbeck Ol. Fil. * * * 1731. After mentioning the original edition of the respective works, subsequent editions, reissues, and translations are accurately recorded; and in each instance the usual information is given as to place and time of publication, as well as the form, number of pages of text and index, and other details. In those works consisting of more than one volume the subjects treated in each volume and the number of pages devoted to each subject are indicated briefly in tabulated form. Refer- ence is also made to contemporary notices and reviews. Linnaean works are appended, which add to the interest of the volume. It is a book which will serve as a most useful guide to the Linnaean literature.—J. M. GREENMAN, The flora of Styria.—Von HavexS has begun a systematic treatment of the ferns and flowering plants of Styria. The first number of this work contains a key to the main groups and sub-groups, which are clearly defined, and a second key leading directly to the families. The enumeration of species follows a natural Sequence, beginning with Ophioglossum vulgatum L. and continuing through the three parts to Chenopodium album L. A concise description of each species 's given in German, and associated with it one finds a fairly complete synonomy and bibliography. Careful attention has been given to habitat and distribution. Text figures are introduced to illustrate certain groups, but the illustrations lack clearness and detail. The nomenclature is in accordance with the Vienna Rules adopted at the last International Botanical Congress. On the whole the work thus far happily combines a semipopular presentation and a degree of scientific accuracy which will make it useful to the local botanist and to the general systematist.—J. M. GREENMAN. _Flowering plants and ferns.—Under this title Wis published the first edition of his manual and dictionary in 1897. A second edition appeared in “994, and now a third’ has come to hand. The purpose of the book is “to supply, Within a reasonable compass, a summary of useful and scientific information about the Plants met with in a botanical garden or museum, or in the field.” The result is a very convenient book of reference. The first part presents an 5 Von Havex, Aucust, Flora von Steiermark. Eine systematische Bearbeitung S . im Hi Blitenpflanzen nebst einer pflanzengeographischen Schilderung des Landes. Vol. 1. a Pp. 240. Berlin: .Gebriider Borntraeger. 1908. oo) C., A manual and dictionary of the flowering pl oo Pun, po: it712. Cambridge: The University Press. 1908. New York: G. : > $2.75. cae ts and ferns. Third Pp. $ Sons. 310 BOTANICAL GAZETTE [OCTOBER outline of the morphology, natural history, classification, geographical distri- bution, and economic uses of the flowering plants and ferns. The second part, to a great extent rewritten, is a dictionary of the classes, cohorts, families, and chief genera, alphabetically arranged. ‘The third part, to which much has been added, is a glossarial index of English names, economic products, technical terms, specific names, etc. Altogether the volume is a most convenient one for any botanist or botanical laboratory.—J. M. C. Library of John Donnell Smith.—In 1905 JoHN DONNELL SMITH presented to the Smithsonian Institution his herbarium, containing over 100,000 mounted specimens, and his botanical library, containing about 1600 bound volumes. The herbarium has been placed in the U. S. National Museum; but for the present the library is to remain in Baltimore. The collection of books is chiefly taxonomic, and is especially rich in the literature of the floras of Mexico and Central America. This valuable collection has been placed freely at the disposal of botanists, and a very complete and handsome author catalogue has been issued by the Smithsonian Institution as a special publication,’ in addition to the regular edition (Contrib. Nat. Herb. Vol. XII. part 1). This disposition of his exceedingly valuable herbarium and library emphasizes not only the generosity but also the scientific spirit of the donor.—J. M. C. Cryptogamic flora of Brandenburg.’—The third part of the volume oD Algae by LemMERMANN has just appeared. It is devoted entirely to the Flagellatae, all of the recognized seven “orders” excepting the last (Euglenineae) being presented, and that one is begun.—J. M. C NOTES FOR STUDENTS Paleobotanical notes.—Natuorst has begun the publication of an important series of paleobotanical memoirs.9 ‘The first deals with Pseudocycas, # n°" genus from the Cenomanian Cretaceous of Greenland. It has gen me considered that leaves of the Cycadeae made their appearance first in the bag and thus considerably antedated the true Zamieae, which are known earl from the Tertiary deposits. The author shows that leaves from Cretaceous deposits, which have been described by various authors as belonging t0 ae or even to the living Cycas, are in reality not to be included in these wane all, since they differ from the existing Cycas in that each leaf pinnule has @ i midrib and is attached to the rachis by a broad instead of an attenuated ated On account of these divergences, the author sets up a new genus, P 7 Catalogue of the botanical library of JoHN DoNnNELL SMITH, presented ou to the Smithsonian Institution, Compiled by ALICE Cary Arwoop. Special Pt tion, Smithsonian Institution, Pp. 94. July 1908. > $ Lemmermann, E., Kryptogamenflora der Mark Brandenburg. Band 3 = Algen, 305-496. Leipzig: Gebriider Borntraeger. 1908. ® Kung. Svenska Vetensk. Akad. Handl. 42:no. 5. 19073 432n0. 3- 1908; 43° no. 6. 1908. 1908] CURRENT LITERATURE 311 The discovery of the duplicate character of the midrib is due to the microscopic examination of leaf pinnules. Four species are described under the new genus. The second memoir is on the cuticle of Dictyozamites Johnstrupi Nath. By the microscopic study of the cuticle of this species, bleached with eau de Javelle and mounted in glycerin jelly, the author shows its close affinity with Otozamites as described by SCHENK. The third memoir is devoted to the study of a lycopodineous cone from the Rhaetic of Schonen, which the author earlier described, with some reserve, as being of cycadaceous affinities, under the name Androstrobus Scotti. A micro- scopic examination of the cone in question, with the aid of eau de Javelle and other bleaching reagents, revealed the fact that it was of lycopodineous afiinities, and the name is accordingly changed to Lycostrobus Scotti. The cone is attached to an apparently herbaceous peduncle about 2°™ in diameter and is about 12° in length. The minute structure of megasporangia and megasporophylls could not be made out. The megaspores were over 0.5™™ in diameter and were characterized by appendages along the triradiate ridges. The rest of the surface was covered with minute spines. The microspores, occurring in distinct. clus- ters, were found in the upper part of the cone, were bifacial as in Isoetes, and were 30 to 50 in diameter. The author comes to the conclusion that Lycostrobus is more nearly allied to Isoetes than any living lycopod. This cone is of great interest from two standpoints. It illustrates how extremely unsafe conclusions as to affinities based on mere superficial characters must be, since 4s an impression the fossil was considered as belonging to the Cycadophyta. Also it goes a long way toward demonstrating that Isoetes is a true lycopod, and hot an appendage of the fern series, as has been suggested by VINES, FARMER, and Capper, The fourth memoir deals with the microscopic investigation of cuticles of fossil leaves, sporangia, spores, etc. Perhaps the most interesting result under this head is the demonstration that ARBER’s Carpolithus Nathorsti (1908) is in reality not a seed of a pteridosperm at all, as is supposed by that author, since the supposed seminal organs were shown by maceration to be microsporangi Numerous abietineous winged pollen grains were found in material from the _ Trias of Hér, T he author comes to the general conclusion: ‘“‘die Gattung Pinus Schon gegen das Ende der Triasperiode, in den nérdlicheren Teilen der Erde ausgebildet war.” This result appears not to be without significance in con- nection with present discussions in regard to the antiquity of Pinus. Smaller winged microspores were also found, which the author does not attempt to refer » me existing coniferous genus. It appears not improbable that they represent the microspores of certain of the Brachyphylloideae, a new subtribe of araucarian Conifers described by Dr. Hotticx and the reviewer. Pa the fifth memoir the author throws additional light on Nathorstia Heer, of described as Daneites from the older Cretaceous of Greenland. By means maceration he has been able to show that the fossil in question is allied to 312 BOTANICAL GAZETTE [ocroBER the living marattiaceous genus Kaulfussia, but differs from it in having the ringlike sorus of sporangia multiseriate instead of simple. In the sixth memoir Antholithus Zeilleri Nath. is discussed, which has been tegarded as the staminate inflorescence of Baiera. It is shown that the fossils in question consist of dichotomously divided, dorsiventral organs, the ultimate divisions of which bore eight sporangia. Consequently they do not resemble the staminate flowers of the living Ginkgo. : Throughout the author gives paramount importance to the microscopic examination of his material, and suggests many ingenious and some novel devices for the preparation of the objects for the microscope.—E. C, JEFFREY. Anatomy of Veronica and Gratiola.—The internal structure of the stem (the rhizome). : The aH contains well-written anatomical diagnoses o ceenrse accompanied by a number of very fine drawings, showing their a : characteristics. It is only to be ae that ot has not been ere for there is no doubt that the structure of this organ must show variations 0° | Small importance, when we bear in mind that among these species of Veron d are both terrestrial and aquatic types, annual and perennial, herbaceous 28 suffrutescent. The fact that the primary root persists in some of them, aot that it becomes replaced by secondary roots in others, might also deserve P° T. *° HUCHEDS, J., Veroniques et Gratiole. Etude histologique et P rer ravaux Lab. Mat. Medic. Ecole Sup. Pharm. Paris §:137- 19°7- 1908] CURRENT LITERATURE 313 eet eS Ce ae Bie ee hen: aera IR | nT q However, very p t as to include the root-system, especially of herbarium specimens.—THEo. Hom. Anatomy of the leaves of Ranunculaceae.—Gorrart' has described the leaf structure of species representing 2 3 genera of Ranunculaceae, nearly all . from the old world. The paper is illustrated by about 400 excellent figures of the leaf outline and the internal structure. So many anatomical details are recorded that an abstract in brief space is impossible. The author has followed the method suggested by his teacher, the distin- guished anatomist A. GRAvis, to examine the leaf at very many places and at various stages of its development, and to give due consideration to the course of the mestome strands from stem to petiole and throughout the blade. In this way one obtains a most complete idea of the structural peculiarities, and such are highly welcome to students of affinities, expressed not only by floral structures but also by internal organization. Much has been written about the validity of several of these genera, considered from a systematic point of view, especially judging from the floral characters. It is therefore interesting to learn m this paper that, so far as concerns the leaf structure, Hepatica is not dis- tinct from Anemone, and the same seems to be the case with Nigella-Garidella, Actaea-Cimicifuga, and Ficaria-Oxygraphis-Ranunculus. However, in respect 'o Oxygraphis, the author has examined only O. Cymbalaria, which in the reviewer’s opinion is no true O graphis, but a Ranunculus. examination of O. glacialis, for instance, would no doubt have led to a different conclusion. On the other hand, Pulsatilla appears to be generically distinct from Anemone, and Batrachium from Ranunculus. Future investigations, for instance, of the singular North American representatives of Ranuculus constituting the section Crymodes, Cyrtorhyncha, and Pseudaphanostemma might lead to the segrega- tion of these from Ranunculus altogether. For such a purpose GOFFERT’S con- tribution is a very important one; and it might be stated at the same time that the same family has been treated by other pupils of Gravis in regard to the Structure of the pericarp and spermoderm, the embryo and seedlings, etc., the result of which have appeared in the Archives since 1897.—THEO. HoL. Prothallia of Kaulfussia and Gleichenia.—One of the results of CAMPBELL’s recent visit to Java is the publication of an account?? of the prothallia of the oriental and monotypic Kaulfussia and of Gleichenia. The account fills in an important 84P In our knowledge of the prothallia and sex organs of Filicineae; and it is of interest to note that the account satisfies the desire for completeness rather than the desire for new things, ** Gorrarr, Jutrs, Recherch Pana les feuilles dans les Renonculacées. i Bot. Univ. Ligge III. pp. 187. pls. 14. rg01- The editors feel justified ~ 48 attention to so old a publication in view of the fact that it has an important bearing Upon the current taxonomic study of the family. Bot, pe aMPBELL, D. H., The prothallium of Kaulfussia and Gleichenia. Ann. Jard. Buitenzorg II. 7269-102. pls. 7-14. 1908. + 314 BOTANICAL GAZETTE [OCTOBER The prothallium of Kaulfussia is said to be the largest among Marattiaceae, a very large one reaching 2.51.75°™; but the usual adult size is 1°™ or more in length and nearly as broad. An endophytic fungus is always present. The _ antheridia and archegonia, restricted to the ventral surface, are also of ususua size. CAMPBELL thinks that probably all the organs of the embryo of Marat- in Kaulfussia. As in other members of the family, the shoot pierces through the prothallium and emerges from the dorsal surface. The prothallia of Gleichenia are also of the “‘massive-midrib” type, more or less lobed, and with an endophytic fungus. The antheridia are restricted to the ventral surface in all species except G. Jaevigaia, in which they occur upon both surfaces. In the species examined they are larger and more complex than recorded in the species examined by RAUWENHOFF, the wall cells being much more numerous, several hundred sperm mother cells sometimes being p uced, and an opercular cell probably always being present. The archegonia are more numerous upon the flanks of the “midrib” than upon its middle region; the necks are very long; and the neck canal cell (except in G. polypodioides) usually divides into two cells. The embryo, so far as the material permitted comparison, resembles that of the Polypodiaceae. The characteristic protostelic condition was observed in sporelings, but it was not discovered whether it persists in the adult form in all species.—J. M.-C. Sexual reproduction in the rusts.—During the last three or four ye ge MAN and Curistman have described a process of. sexual reproduction in the rusts. Their accounts are not in entire agreement, and so the ground has = traversed by Oxive,"s with an unusual wealth of material. About forty speci® were examined, and the most favorable form for the study undertaken pee to be Triphragmium ulmariae (Schum.) Link, on Ulmaria rubra Hill, a — form similar to the species of Phragmidium studied by BLACKMAN and se MAN. The two fusing cells (‘« gametes’’), as well as their nuclei, were foun iv be approximately equal, but for reasons given in detail it is concluded that of differ. somewhat in time of development. The equality and sexual = both the fusing cells are statements opposed to those of BLACKMAN. es concluded that the sterile cell (at the tip) is not an abortive trichogyne, - a “buffer cell” of the gametophyte. Conjugation takes place through pe foration developed in the contact-walls. It may begin through @ Very © the conjugation pore (observed by BLACKMAN), but this is regarded oe eke inning of a larger perforation. In the study of the various vee = con- divisions it was discovered that they are all mitotic, each nucleus — fo with jugate divisions acting independently. These nuclear divisions, conduct it was the aid of centrosomes, are described in detail; and in Triphragmium pie ascertained that the chromosomes are probably eight in number. se ——__. » «tone in the *3 OLIVE, Epcar W., Sexual cell fusions and vegetative nuclear division® - Tusts. Annals of Botany 22: 331-360. pl. 22.1908. | 1908] CURRENT LITERATURE 315 rence of one or more multinucleate cells at the base of certain young aecidia is considered, and the conclusion is reached ‘‘that they are sporophytic structures, and that they result from the stimulated growth which follows the sexual cell fusions.” This is opposed to the idea (CHRISTMAN) that the “fusion cell” functions at once as a “basal cell’’ at the bottom of each row of spores.—J. M. C. Gnetales and Angiosperms.—Last year ARBER and PARKIN announced’ their “strobilus theory of angiospermous descent;” and now they have applied it to the interpretation of the relationships of Gnetales.ts There is much to commend their general view, without conceding all the details cited; in fact the reviewer has long since reached the same conclusions as to the character of the - strobilus of Gnetales, and has remarked upon its similarity to such inflorescences as those of the Amentiferae. The authors do not regard the Gnetales as a modern group, although at present unknown as fossils. The three survivors of this ancient group have “pro-anthostrobili,”*® evident in the staminate “flower” of Tumboa and reduced in the other “flowers” of the group by the suppression of one set of sporangia. To the authors the strobilus of this group is:the so-cal “flower;” and the strobilus of current terminology is an aggregate of strobili. Based upon this strobilus situation, the authors regard Gnetales as a phylum of = having a common ancestry with angiosperms in the hypothetical hemiangiosperms,” and in many respects following parallel lines of develop- ment.—J. M. C. Origin of angiosperms.—LicNIER"” has discussed the recent paper by ARBER and Parkin,?® in which the origin of the angiosperm flower (of the Ranales type) Is traced to the bisporangiate strobilus of Bennettitales. From this view L1GNrER dissents, as he regards the strobilus.in question as representing an inflorescence tather than a flower. To him the intraseminal scales are not sterile carpels or Sterile lobes of carpels, but bracts in whose axils the ovuliferous stalks appear. This strobilus, therefore, is a compound one, as are the ovulate strobili of many of the Coniferales and both strobili of the Gnetales. LrGNreR agrees to the idea that the Ranales type of flower is the most primitive, but he would derive it from Sieur “# Review in Bor. GazETrE 44:389. 1907. _‘S Arper, E. A. NEWELL, AND PaRKIN, JOHN, Studies in the evolution of the angiosperms. The relationship of the angiosperms to the Gnetales. Annals of 5- 1908. __ An “anthostrobilus” is an axis bearing microsporophylls and megasporophyils, with the latter above the former. A “pro-anthostrobilus” is the variety in which the Pollen reaches the ovules (gymnosperm), the strobilus of Bennettitales being an cx aes while a “eu-anthostrobilus” is the variety in which the pollen is received by Megasporophyll (angiosperm). *1 Licnter, O., Le fruit des Bennettitées et l’ascendance des Angiospermes. Soc. Bot. France IV. 8: I-17. 1908. 8 Bor, GAZETTE 44:389. 1907. 316 BOTANICAL GAZETTE [OCTOBER the earlier cycadophyte stock. Accordingly he introduces before ARBER and ParKIN’s ‘‘pro-anthostrobilus” an evolutionary stage characterized by the group- ing of filicinean microsporophylls and megasporophylls in monosporangiate strobili, and to this hypothetical stage he gives the name “‘pteridostrobilus.” This stage was temporarily a common one for the general cycad and angiosperm phyla; and at this stage the cycads practically stopped, with reduction of sporo- phylls; while the angiosperm phylum proceeded to the establishment of the bisporangiate condition, the evolution of angiospermy, the transformation of the habit of the vegetative body, etc. According to Licnrer, the Bennettitales represent a different phylum, which branched from the cycadophyte phylum after the angiosperms, but still at the pteridostrobilus stage—J. M. C. Nitrogen fixing bacteria.—In a short preliminary paper’? BREDEMANN sum- marizes the conclusions deduced from his study of nitrogen’ fixing bacteria of the Clostridium type. Eleven cultures of the so-called “species” of various authors were compared with sixteen types isolated by himself. These types were from many sources, particularly soil from different parts of the world. A comparison of these forms cultivated under proper conditions for considerable iods has convinced him that all must be considered as a single species, 4 ethods, Most Saprolegniaceae. He has found it possible to isolate species of Sapro’ co ere used 1n substances de BREDEMANN, G., Regeneration der Fahigkeit zur Assimilation Stickstoff des Bacillus amylobacter A. M. et Bredemann und der zu dieser - Bak- gehérenden bisher als Granulobacter, Clostridium usw, bezeichnete anaeroben terien (Vorlaufige Mitteilung). Ber. Deutsch. Bot. Gesell. 26a: 362-368: 1908. 2° Kaurrman, C. H.. A contribution to the i of the : + Ge physiology ig ant with special reference to the variations of the sexual organs. Annals of Botany 361-388. pl. 23. 1908. 1908] CURRENT LITERATURE 317 effect the production of sexual organs were haemoglobin and leucin, as found also by Kiegs. The effect of nutrition upon the differentiation of reproductive - and vegetative processes was amply confirmed; but not all species produce sexual organs under the same conditions, showing a physiological as well as a morphological distinction. S. hypogyna, in which true antheridia do not develop, was made to develop antheridia under proper nutrient conditions. The varia- tions induced were so extensive as to include all the characters used for diagnostic purposes, and the author makes the suggestion that a species can be defined in terms of its behavior in an established standard culture. The conclusion is reached that there are a great many entirely distinct forms, physiologically so at least, which may be regarded as elementary species in the sense of DEVRIES. The whole tendency of the investigation is to confirm the doctrine that sex in plants is determined by external conditions.—J. M. C. : The Sporangiophore.—Miss BENSON?? has emphasized the morphological mportance of the sporangiophore, and has extended its application. Originally applied in Sphenophyllales, Equisetales, and Psilotales, she would extend its application to all pteridophytes. Objection is made to BoweERr’s application of the term in Ophioglossales to the ‘‘fertile spike.” In the Filicales the sorus (or Synangium) is the sporangiophore; while in Lycopodiales it appears in a teduced” formas the subarchesporial pad. Primarily it is a unit structure that appears on the axis, but may be “taken up on to” the leaf, as in all known ferns and many Lycopsida. The definition suggested is that “‘a sporangiophore is a Structure characteristic of the sporophyte of Pteridophyta, and consists of a central, generally pedicellate mass of sterile tissue, with sporogenous regions : Pying one or more sporangia, which may be terminal, lateral, or basal.” It is further suggested that even Cordaitales and Taxineae may be forms whose Sporangiophores have never been “taken up” on leaves. All this means 4 monophyletic origin for pteridophytes, with the sporangiophore (as now defined) as a fundamental and unifying structure of the sporophyte. Such a hypothesis fees .s about, and it has enough facts to support it to make it seduc- aes Cc seta Nymphaeaceae, Cabombaceae, and Ranunculaceae. Recently VAN So ‘eM’? has discovered this singular structure in Sorghum halepense Pers. far only the monostelic structure has been observed in the aerial and sub- a — be f the numerous Gramineae examined. While the aerial send oe a is monostelic, the rhizome possesses a large number of meristeles oe BENson, M., The sporangiophore—a unit of structure in the Pteridophyta. Phytol. 7:143-149. 1908. “ag Ttecnem, Pu., Une graminée & tige shizostélique. Ann. Sci. Nat. Bot. IX, 52371. 1907. 15 BOTANICAL GAZETTE [ocroBER in the cortex, which are of a very different size, but each is surrounded by a special and very plainly differentiated endodermis, in which the Casparyan spots are readily noticeable. The structure of the mestome strand in each is typical, and does not differ from that known so well from the Gramineae in general. The fact that the endodermis is differentiated at a very early stage, and that the inner cell walls become thickened long before the vessels and the adjoining tissues become lignified, makes this schizostelic structure plainly visible in the young rhizome, in the internodes, and partly also in the nodes. It would be interesting to know whether the structure is not to be found in other grasses.—THEO. HOLM. Morphology of Podostemaceae.—WENT?3 has made some remarkable obser- vations on the ovule of Podostemaceae. He has obtained abundant material and finds the several species studied very consistent with one another and very inconsistent with other Angiosperms, A future more extensive paper is promised, which will deal with all the features of the family. The outer integument develops first and forms the micropyle. Later the inner integument develops, but never incloses the embryo sac region of the nucellus, The hypodermal megaspore mother cell caps an axial row of cells, which first elongate and then disorganize, resulting in a pseudo-embryo 5a¢ inclosed by the inner integument. The true embryo sac enlarges but little, and the embryo grows into and occupies the pseudo-sac. After the first division of the megaspore nucleus, the primary antipodal nucleus degenerates promptly, 5° that there are no antipodal cells and no antipodal polar nucleus. he four micropylar nuclei form as usual, but the micropylar polar degenerates promptly, so that there is no “double fertilization” and no endosperm, It is to be regretted that alcoholic material and scattered stages did not permit absolute certainty oP many points.—J. M. C. Tracheae of ferns.—GwyNNE-VAUGHAN?+ has investigated the xylem of some of the recent ferns, and concludes that the current statement that the meta ston. The conclusions are that the xylem elements of pteridophy'*s as vessels with true perforations in their longitudinal as well as ™ bos niece hee continuous in the middle of the wall. It is probable : in oS *9 Weer, F. A. F. C., The development of the ovule, embryo 54¢ and ¢88 ostemaceae. Recueil Tray. Bot. Néerland. 511-16. pl. I. 19 A Lee anes D. T., On the real nature of the tracheae in the nnals of Botany 22°517-523. pl. 28. 1908. 1908] CURRENT LITERATURE 319 more or less rounded pits preceded the transversely elongated pits of the scalari- form type in the Filicales—J. M. C. Origin of Sphenophyllales.—In 1903 LicNTER?S published his view that the Equisetales and Sphenophyllales are of filicinean origin. Recently this disposi- tion of the Sphenophyllales has been opposed, especially by Scott, and by the anatomical work of Miss SYKES. LIGNIER has now resumed the discussion?® and reaffirms his former position, with additional argument. He claims that the “fertile leaves” of Sphenophyllum cannot be homologized with the sporangif- erous structures of Tmesipteris; but that their ‘‘sterile pinnules” are compar- able with those Archaeopteris. The “fertile pinnules,” at the same time, are of the same type as those of the Primofilices. Therefore, LIGNIER concludes that the Sphenophyllales ought to be ‘‘attached” to the Primofilices and not to the Lycopodiales. A number of secondary characters also are used to strengthen this view.—J. M. C. Sieve tubes.—An elaborate histological investigation of the details of develop- ment in sieve tubes of angiosperms’ has been made by Hixz.?7 It appears that the young cell wall which is to form a sieve plate, is at first pitted, the pit-floor being penetrated by one or a group of fine protoplasmic threads, which, after some change of the adjacent cell wall, ‘‘begin to be bored out to form slime strings, apparently by a ferment.” These slime strings enlarge and merge, $0 that finally one large slime string occupies the place of the group. This is always . in a protoplasmic tube, which lines each pore of the plate, and the Pore itself has a callus lining covering the cellulose part of the wall. Many further details are given and the usual teleological causes assigned for the pro- cesses. The paper contains an excellent historical summary.—C. R. B. Hygroscopic movements.—STEINBRINCK and ScHINz, by studies on some desert Plants, support further the view that the internal structure of the thickened walls, 4s well as differences in the tissues, are the cause of the warping movements of fruits and other parts.*® They find that lignified walls really swell and shrink bending organ. Incidentally they establish the “true” Jericho rose as Anastatica stray L., and not Odontospermum pygmaeum (DC.) Benth. & Hook.— -R.B, Sa : *S Licnrer, O., Equisétales et Sphenophyllales. Leur origine epeen mune. Bull. Sci. Linn. Normandie V. 7293- 1903- | i. *6 Licnier, O., Sur Vorigine des Sphénophyllées. Bull. Soc. Bot. dongs *278-288. 1908. *7 Hitt, A. W., The histology of the sieve tubes of angiosperms. Botany 22:245-290. pls. 17, 18. figs. 13. 1908. = STEINBRINCK, C., and Scutyz, H., Ueber die anatomische Ursache der hygro- en Bewegungen der sog. Jérichorosen und einiger anderer Wiistenpflanzen. 908 Annals of ra 98:47 I-500, 1 320 BOTANICAL GAZETTE - [ocroBER Biology of diatoms.—Cell division is described by BERGON?? for Biddulphia, but the nuclear details are not shown. No centrosomes are - ae principal point of interest in the formation of auxospores is that not one, but two are formed in each cell. Spores (the so-called microspores) have been described and the observations have been disputed. Although the existence of such spores might safely be conceded, this paper describes the development of sporangia and spores so clearly that there can be no doubt either as to their existence or the mode of their formation. —CHARLES J. CHAMBERLAIN. Sterile anthers of Ribes.—JaNczewsk1°° has discovered an interesting situa- tion in the pollen of Ribes. In the genus there is every stage between entirely fertile and absolutely sterile anthers. Certain subgenera and a few hybrids habitually develop perfect pollen. Most common among the hybrids, however, is a mixture of sterile and fertile pollen grains, in varying proportion. r tain hybrids and in the subgenus Parilla the pollen is persistently inert. Degener™ tion generally occurs after tetrad formation, but sometimes in the mother cell stage—J. M. C. Protoplasmic rotation.—BrERBERG3" concludes that rotation and streamms is neither a widespread nor usually a normal phenomenon, but he does not accept ss KELLER’s view that it is a symptom of dying. On the contrary, he fine that it accelerates the transfer of materials more than threefold over per : move- or are or are not permeable in all parts, are less valuable than his experimental ” work.—C. R. B. Rusts.—O IvE3? has published a popular account of cereal rusts and their life-histories. He confesses that “the problem of the prevention of rusts 1S pe * difficult one that many points still remain to be solved;” and states that main thing which can be done at present is simply to record the present al our knowledge as to the nature of these complicated organisms, and to awit" interest in a knowledge of their habits.” —F. L. STEVENS. 29 BERGON, P., Biologie des Diatomées.—Les processus de division, Rev. G ment de la cellule et de sporulation chez le Biddulphia mobilensts Bailey : Botanique IV. 7: 327-358. pls. 5-8. 1907. : acai Sci. 3° JANczEwsxt, Ep., Sur les anthéres stériles des groseilliers. Bull. “@~ ~ Cracovie 1908: 587-596. pl. 24. " Hofftranspott 3t BIERBERG, W., Die Bedeutung der Protoplasmarotation fiir den Hi in den Pflanzen. Flora 99:52-80. 1908. “Stes 3? Oxtvg, E. W., Rusts of cereals and other plants. S. Dak. — eo é Bull. 109. June 1908. gaged eee ears & @) Toc 8 i= © zi COULTER and JOHN M F “gs - m fy 3 a Leys. Allies from Europe and North | a tions on Polyporus a a Morphology of Phyllocladas e ay of the ri fote on Nume Che Botanical Gazette A Monthly Journal Embracing all Departments of Botanical Science Edited by Joun M. CouLTER and CHARLES R. BARNES, with the ee of other members of the botanical staff of the Upheeniey of Chic Issued November 16, 1908 Vol. XLVI CONTENTS FOR NOVEMBER 1908 No. 5 Rapes ATIONS eal POLYPORUS LUCIDUS LEYS. AND SOME OF ITS ALLIES OM EU E AND sg ead Sep ee FIVE FIGURES AND PLATE osed — F. “sim 321 ARE MORPHOLOGY OF PHYLLOCLADUS ALPINUS, CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 118 (WITH PLATES Xx-xxul). WV. Johanna Kildahl 339 NOTE ON NUMERICAL VARIATION IN THE DAISY. C. A. Danforth - . - - 348 THE VASCULAR ANATOMY OF THE SEEDLING OF D/OON EDULE. Contrisu- TIONS FROM THE HULL BOTANICAL LABORATORY IIg (WITH PLATES XXIII-XXIX). Reinhardt Thiessen zs s ? . a : : 2 Z % 5 e - 357 - MRLEFER ARTICLES New Cotorapo SpEcIEs oF aay) (WITH TWO freee: Francis ex apaed - 381 SEXUAL CONDITION IN FEGATELLA. A. F. Blakeslee - - 384 oa A New CHARACTERISTIC OF ENGELMANN Spruce. E£, R. Sim - - : - 386 4 cuRRewr LITERATURE «BOOK REViIEws es ee eee UT ee Ae THE WIESNER FESTSCHRIFT MINOR NOTICES ie Tint Cee eae ge er ie oe ee el a ce ae a NOTES FOR STUDENTS - : : é - : : ‘ J 2 ts - 389 Botanical Gazette is published monthly, [The subscription price is $7.00 per year; the pric le copies is 75 cents. ‘] Postage is prepaid by the revaatn ty on oo oo from the United States, orto Rico, Panama Canal Zone, Republic of Panama, Hawaiian Islands, Philippine erat ngh i in co ion, 84 cents on annual subscriptions (total $7.84), on single copies II one (total 86 cents). deg ces should be made payable to The University of Chicago Press, and s be in Chicago or hee EE ance, postal or express money order. If local check is used, 10 ia must be added iam Wesley & Son, 28 Essex pais Strand, London, are appointed sole European agents and ‘le. rized to quote the follow be $4 ces; Yearly subscriptions, including postage, £1 12s. 6d. each; oP es, including postage, 35. 6 sale T missing numbers set ia be made within the month following the regular month of publi- The publishers expect to supply missing numbers free only when they have been lost in transit. ; Correspondence should be addressed to The University of Chicago Press, Chica ‘Communications for the editors should be addressed to them at the University of Chicago, Chicago, Il, are requested to write scien and proper names with particular care, to use t the metric tors ntific of weights and measures, and in citations to follow the form shown in the pages of the Bor ata Biber I excess of thi irty-two printed igh are not aaah saad aia the author is willing to aie on additional pages, in which case the ber of pages nig ; Ms are furnished wit hor onl nis ‘suitable originals aie suppli ied. ‘coke Suggestions made : eg hou cos oa Fon, ! will be sent on application. It is sivisable to ired i ffered. om an order blank which a accompanies the proof; a copy a wil be sent on rather tien Atguse 21, 1895, at the Post-Office at Chicago, as second-class matter, under Act of See! March 3, 1879. VOLUME XLVI : NUMBER 5 BOTANICAL GAZETTE NOVEMBER 1908 OBSERVATIONS ON POLYPORUS LUCIDUS LEYS. AND SOME OF ITS ALLIES FROM EUROPE AND NORTH AMERICA? GEORGE F. ATKINSON (WITH FIVE FIGURES AND PLATE XIX) The close relationship between the fungus flora of Europe and North America has long been recognized. There are many species which are common to both countries. This in a large measure is due to the same general conditions which have long been recognized in explaining the similarity between the spermatophytic floras of the two countries, namely, the strong evidence presented by certain geologic periods that many centuries ago the two floras were con- tiguous in the arctic regions, at a time when the climate there was mild enough to permit the growth of those species and genera, con- tributing through their progeny the present representatives, which have survived the climatic and edaphic rigors to which they were subjected during the subsequent glaciation of the arctics, and the shifting glacial movement farther to the south, The fungus flora of a Country bears a very close and important ecological relation to other plants, especially to the spermatophytic flora, whether as para- Sitic, humus-dwelling, or wood-destroying species. They are ‘camp followers” of the higher plants. Because of this symbiotic and meta- biotic relation of the fungi to other plants, in a great measure their Sdging and migration is coincident with that of their hosts. In the “ase of the forest fungi there are some interesting examples of tena- Clous adherence to specific hosts, or to descendant species which have become separated in the migratory movement from the parent * Contribution from the Department of Botany, Cornell University, No. 130. 321 322 BOTANICAL GAZETTE [NOVEMBER stock. There are also interesting examples of a shift from one host to a host of another related genus, instead of to a species of the same genus, where in the migration the specific hosts are not evenly dis- tributed over the area of general migration from a given region. Pleurotus ulmarius Bull., while occurring on other frondose trees, is more common on the elm both in Europe and North America, although our native species of elm is different specifically from the European elm. Annularia jenzlii Schulz. was first collected in Hungary on Tilia ewropaea and does not seem to be common or widely distributed in other parts of Europe. It has been collected once at Ithaca, N. Y., on our native species of basswood, Tilia americana. Fomes fraxineus (Bull.) Fr. seems to be confined to the ash, occurring on the European ash in Europe and on our native species in the United States. Fistulina hepatica (Huds.) Fr. occurs in Europe especially on the oak, but sometimes on beech and chestnut. In North America it occurs most commonly on the chestnut, but is reported also on the oak, European species of oak not occutting naturally in this country. Many other similar examples might be enumerated. In a number of cases the fungus species seems to have undergone little or no change, although now separated for centurie on two different continents and subjected often to widely different environmental conditions, In other cases the North American repre sentative of European species seems to have undergone 4 change, Whether gradual or sudden we cannot say, so that it presents certain constant characters worthy often of specific separation, while resem- bling in a striking way the European species. One of these interesting problems is presented by Poly ah lucidus Fr.? (Boletus lucidus Leys.3). My first acquaintance with What appears to be the typical form of P. lucidus in Europe os the autumn of 1903, when I collected a specimen growing from - Toot of a dead frondose tree in the Bois de Boulogne, Paris. Two eg later, while visiting M. E. Bouprer at Montmorency, — Paris, he gave me a fresh young specimen which had been sent from one of his numerous correspondents in France. It is a large cae handsome fungus, varying considerably in size and form. The typical forms are stipitate, with a lateral pileus. In these ae ? Flora Halensis 300. 1783. 3 Syst. Myc. 1:353- 1821- j if f 2 1908] ATKINSON—POLYPORUS LUCIDUS 323 the stipe is usually quite fully developed before Be oe in me pileus, the latter developing gradually as a latera _extens 3 free end of the stipe and becoming dimidiate, derebatis or Sat ae form, usually with an entire margin, but sometimes more Fic. (Natural s ° ‘é 7, id m”? Leys.) ‘Ganoderma pseudoboletum (Jacq.) Murrill (Polyporus “Jucidu ize), from France ‘Tenate or rarely somewhat lobed. Sometimes the pileus “ig pd Sessile, the stipe being reduced to a stout tubercle, especially bs ss the plants grow directly on the side of alog. The plants occur he y or in clusters, and sometimes imbricated. One of the stri : : characters, which is also a peculiarity of a number of other species, 324 BOTANICAL GAZETTE [NOVEMBER is the formation of a colored viscous substance on the surface of the stem and pileus which dries and hardens into a smooth, hard, thin, lustrous crust or “skin,” which gives the plants a varnished appear- ance. In typical forms of P. lucidus this is a reddish chestnut, or marron color, varying to darker colors or even blackish in some forms of the species. The surface of the pileus is often marked by concen- tric rings and furrows, usually not very pronounced, and usually toward or on the margin where the rings are often close together. The surface is often radiately rugose. The pileus varies from 2-25°" or more in diameter and 1-4°™ thick behind. The stipe varies greatly in length, and from o. 5-4°™ in diameter. The tubes are long and slender, brown within, the mouths circular, angular, white or yellowish, finally yellowish brown, with the dissepiments thin and acute. The trama or context of the pileus is pallid to brown, the portion next the tubes being darker brown, about the same color as the tubes, while it is paler to almost white next the varnished crust. The context of the stem is brown, with more or less distinct transversé Concentric zones, which are also found to some extent in the pileus, and there is a distinct radiating fibrous structure extending into the pileus. The context is also soft and “punky.” Before the plant is mature, and while it is in different stages of development, the growing end of the stipe and the growing margin of the pileus are whitish, then changing to reddish yellow and finally chestnut as the varnishing becomes complete. BULLIARD® and Giter® figure young plants showing the lighter-colored marge: This condition is different from the yellowish unvarnished condition of the pileus of P, curtisii Berk.” from the southern United States, with which Murrir8 compared BULLIARD’s and GILLET’s figure. The fact that the typical form of P. Jucidus occurs in Europe 0? frondose trees lends additional interest to the most common form of this species in the United States, which occurs on the hemlock- + *See Encerron, C. W., The rate and period of growth of Polyporus pact orreya. 7289-97. 1907. C ice obliquatus Bulliard. Herb. de la France. pl. 7, fig. A, pl 459: fas: Bs“ * Polyporus iucidus Fr. Gillet. Champignons de la France 666. i olyporus curtisii Berkeley. Hook. Jour. Bot. 1: ror. 1849. ull. Torr. Bot. Club 29:604. 1902. 1908] ATKINSON—POLYPORUS LUCIDUS 325 spruce (T'suga canadensis). This form can be distinguished from the typical form on frondose trees in Europe only by the fact that it stoWs on a conifer, the hemlock-spruce, rather than on frondose trees, and perhaps by its somewhat softer and perhaps slightly lighter- Fic, 2.—Ganoderma pseudoboletum forma montanum Atkinson (X#), on dead spruce, Jura Mts., France. 326 BOTANICAL GAZETTE [NOVEMBER colored context, and the longer persistence of the individuals of the European form, since this usually does not disintegrate so soon. But these characters vary in individual plants and seem to mark our form on the hemlock-spruce merely as a physiological or biological form of the European species, rather than as a distant species as it is regarded by MuRRILL® (p. 606). P. lucidus is rarely reported on conifers in Europe, though it probably is common enough in certain of the mountainous regions. KarsTEN’? reports it on Abies excelsa in Finland. In 1905 I found it quite common in the Jura Mountains‘' near Pontarlier and Bou- jeailles, Province Doubs, France, on dead stumps and logs of the common fir (sapin) of that region. These plants, while showing great variation in form, do not depart in this respect from the typical orm. The stem varies from lateral to central in some individuals. There is, however, a marked difference in color, the Jura specimens on the fir having the varnished surface darker in color than those which I have seen from frondose trees in Europe, but also darker than our form on the hemlock-spruce, the color being 4 dark ma- hogany red, finally becoming nearly black. The color of the context 1s brownish like that of the typical form. So far as I could observ®, I could see no evidence that this form is perennial, nor have I seen perennial specimens of the typical form. I sent specimens of these plants collected on the fir in the Jura Mountains to M. E. BouDIeER, of Montmorency, and at the same time some of the American _— collected on the hemlock-spruce. The latter he pronounced a typic form of P. lucidus, while,the former he regarded merely as 4 black form of the same species, which he says grows in the Vosges and Jura in France and Germany. The spores are identical in structure and size in all the above-mentioned forms. The form in the southern United States on roots, stumps, ¢ of frondose trees, seems to be distinct enough to be regarded 98 4 distinct species. BERKELEY so regarded it and described it as . ° Ganoderma tsugae Murrill. The Polyporaceae of N. Am. IL. The genus Gane derma. Bull. Torr. Bot. Club 29:599-608. 1902; N. Am. Flora 9#:118: 19°: to KARSTEN, P. A., Myc. Fenn. pars tertia, Basidiomycetes, in Bidrag till RAP nedom af Finlands Natur Och Folk 2 52254. 1876. : 1 The collection and study of this material, with many other European sd ’ was made possible because of a grant from the Botanical Society of Am ATKINSON—POLYPORUS LUCIDUS 327 1908] “Buljorer) YON wor s1ayjo ‘sexoy, tot} jued jerues {qpinpy (“yI0g) ses2y4na DULAIPOUDH—*E “OL T 328 BOTANICAL GAZETTE [NOVEMBER curtisii.‘? The general form of the plant is the same as that of P. lucidus, but the pileus is rarely and then only slightly varnished, and is yellowish in color, or with reddish-yellow spots and zones. The stem is exactly like that of P. Jucidus and is varnished, reddish chest- nut in color. In the extreme south forms with a central stem are more common, and then the pileus is more or less depressed in the center, as in fig. 2, which represents a specimen collected in Texas by A. M. Fercuson. The surface is often zonate, faintly or strongly sulcate, and sometimes radiately rugose or corrugated toward the margin. While Murritt first considered this as merely a geographi- cal form's of P. lucidus (Ganoderma pseudoboletus Murr.), he now treats it as a distinct species'* (G. curtisii [Berk.] Murr.). Another form which has come under my observation was sent me by Mr. M. E. Harp, of Chillicothe, Ohio, who collected it from dead buried roots of oak, growing among Datura stramonium. These plants (fig. 5) resemble the typical European form in color and consistency. These individual specimens were not fully grown, and therefore the margin is lighter colored. The pileus as well as the stem is laccate or varnished. There are some differences in the spores which will be discussed below. Another interesting form was received from E. R. Lak, of Cor- vallis, Oregon, in January, 1905. It is a large stipitate plant with a lateral pileus, the pileus measuring 14°™ long by 12° broad and 5-5°™ thick. The pileus is tumid and covered with a thin crust, which is brittle, dark reddish brown, and laccate, similar to the crust of the stem. The context of the stem is also white and shows @ fibrous structure which radiates out into the pileus. The tubes ar slender, cinnamon brown, and 2-<°™ long. The plant was growing apparently on burnt ground from a root, probably of some conifer. In this specimen the varnished crust of the pileus extends over the under side of the margin and over the hymenophore for @ distance of 0.5-1°", and a new stratum of tubes 4™™ in length is deposited over the remaining portion of the hymenophore. In sections of me hymenophore this stratum tends to break away rather easily from = "2 Polyporus curtisii Berk. Hook. Jour. Bot. 1:101. 1849- *3 Bull. Torr. Bot. Club 29:602. 1902. 4 N. Am. Flora 92:120. 1908. 1908] ATKINSON—POLYPORUS LUCIDUS 329 Fis. 4—Ganoderma oregonense Murrill, from Corvallis, Oregon (natural size). Point of attachment with the older portion. There is also a faint hncation of the main portion of the hymenophore, but whether his is due to successive annual layers is doubtful, and can be deter- 330 BOTANICAL GAZETTE [NOVEMBER mined only by observation of individual plants from year to year. They appear more likely to be the result of periodic variations in a single season’s growth, like some of the similar strata in Fomes fomeniarius. The plant has the appearance of being normally an annual, which under certain conditions may persist for a second season and develop a second depauperate layer of tubes; or this layer may be developed at the close of the first season, often some unfavorable condition inhibiting the growth for a longer period than usual. It appears to be specifically identical with Ganoderma orego- nense Murrill,*5 recently described from Oregon as growing on a log of Picea sitkensis. The spores of the species discussed in this paper present some very remarkable peculiarities in form and markings, which seem to have been misinterpreted by all those who have attempted to describe them up to the present time. During the past autumn and winter I have made a critical examination of the spores of the species mentioned above, and have not been able to confirm the de- scriptions thus far given. KArsTEN in 1889'° says the spores sob warty (sporerna aggrunda eller elliptiska, vértiga, gulbrunaktiga). PATOUILLARD in 188777 describes and figures the spores of the - got Ganoderma as verrucose (verruqueuses) and cites Ganoderma lucidum as one of the typical species. Later'® (p. 66) this is repeated where he places Ganoderma lucidum in the section of Ganoderma having verrucose spores (spores verruqueuses). SACCARDO’? says that the spores of this species are slightly verrucose (forma typica spors ovoides, leviter verrucosis), and BrEsADOLA states that they ar verrucose.*° MuURRILL in 1902?" and again in 19087? describes them 15 N. Am. Flora 9?: 119. 1908. *6 Kritisk Ofversigt af Finl. Basidsv. 327. 18809. *7 Les Hyménomycetes d'Europe 142. pl. 3. fig. 21. 1887. "Le genre Ganoderma. Bull. Soc. Myc. France 5:63-83. pls.'I0, If- ne also PATOUILLARD, N., Essai taxonomique sur les familles et les genres der: BY mycétes 105. fig. 58, 3b. TgQ00. 79 Sylloge Fung. 6:157. 1888. 2° Hymenomycetes Hungarici Kmetiani. Atti Acad. Sci. III. 3:73- 1897- * Bull. Torr. Bot. Club 29:601. 1902. 22.N. Am. Flora 97: 118. 1908. 1908] ATKINSON—POLYPORUS LUCIDUS 331 as verrucose in several species (Ganoderma tsugae Murrill, G. lucidum [Leys.] Karsten, G. curtisii [Berk.] Murrill, and others). In studying the spores of these species I have been surprised to find that they are not echinulate or roughened. The spore wall is smooth, that is, there are no elevated or projecting portions of the surface. But the spores have a very peculiar structure, which re- Fic. 5.—Ganoderma subperforatum Atkinson, from Ohio (natural size). quires very careful examination to interpret properly, and sometimes the use of the oil immersion lens is necessary to resolve clearly the characteristic structure of the wall. On a first examination of the ‘pores with the dry objective, they appear warty or roughened ; ut the appearance is so peculiar that I was not content with-this (efinition and sought to determine more accurately the nature of the Peculiar structure. When the upper or lower surface of the spore is ™ the focal plane, the wall of the spore presents the appearance of 332 BOTANICAL GAZETTE [NOVEMBER being verrucose from the presence of numerous brownish or yellowish- brown points; but when one examines the wall at the middle focal plane, these colored dots are seen not to project beyond the outer surface of the wall, though both above and below the middle focal plane they do appear as echinulations. The structure seemed to be so puzzling that I was led to employ the oil immersion lens (Zeiss apochromatic homogeneous immersion lens, equivalent focus 1.5" and compensation ocular 6). This revealed the true structure of the spore wall. It is hyaline or nearly so, and is perforated with numerous slender rodlike extensions of a brown or yellowish-brown substance, which appear as if they might be projections of the colored content of the spore. These do not extend beyond the outer surface of the wall, and they radiate from the endospore through the hyaline wall, They are especially prominent at the smaller end of the oval spore where the hyaline wall is considerably thicker, sometimes forming a broad conelike cap to the spore. In order to demonstrate this peculiar structure beyond doubt, photomicrographs were made of four different species and forms, and these are reproduced in pl. 19. The spores which were lying so that the middle plane was in focus show very clearly that the wall is smooth, and that it is perforated with these short, dark-colored, rodlike extensions. These are very evident all around the spore, but are remarkably prominent at the apex, especially in those spores where the broad conelike hyaline cap is still intact. Where the middle plane of the spore is not in the focal plane, the spores appear “warty,” but this is only an optical illusion. This is especially striking in fl. fig. 6, where the middle plane of nearly all the po was out of focus. For the species from which these photomicro- graphs were made the reader is referred to the description of figures. The fact that the spore wall is hyaline or subhyaline, and perforated with dark lines, gives such prominence to the latter that they - apt to be taken for warts or echinulations when the examination hasty. The hyaline portion of the spore wall appears also to be of a less firm consistency than the colored perforations or lines, and if the spores dry at a certain age, perhaps before they are quite ma ture, the hyaline portion of the wall appears often to shrink or colla somewhat, thus making the colored points stand out as echinulations, 1908] ATKINSON—POLYPORUS LUCIDUS 333 but a careful examination with the oil immersion lens reveals their true structure. . Besides the markings of the spores of these species, there is another peculiarity which has been erroneously interpreted by those who have tried to describe them. This peculiarity relates te the form of the spore. PaTouILLARD?3 in 1889 describes them as truncate and emarginate at the base (tronquées et echancrées & la base) and in 1900*4 simply as truncate at the base. BRESADOLA?S says the spores in Ganoderma lucidum are obovate, at length truncate at the base (sporae obovatae, demum basi truncatae). Murrii?® describes them in several species as follows: ‘Spores ovoid, obtuse at the summit, attenuate and truncate at the base.” But a careful study of the spores shows that exactly the reverse is true. The base of the spore is the broadly rounded end, while the apex is the narrowed, “truncate” end. In Ganoderma lucidum (Leys.) Karsten from Europe, including the forms collected by myself on the fir in the Jura Mountains, in G. tsugae Murrill and G. curtisii (Berk.) Murrill, both from the United States, the spores are all similar and practically identical. They are ovate in form, and when they are lying so that they can be seen in side view, they are seen to be more or less inequi- lateral, that is, one side is more convex than the other. The place where the spore was attached to the sterigma is at the side of the broad rounded end opposite the convex side. Sometimes a minute _ angle can be seen here where the sterigma was attached. Boiling the Spores in a weak solution of potassium hydrate brings out the entire Structure more clearly, and at this point, where the sterigma was attached, the spore wall is very thin, there being a slender channel *xtending from the endospore almost through the epispore to the Point where the sterigma was attached. The treatment with potash, OWever, is not necessary in order to demonstrate the characteristic Structure of the spores described above in these species. An exami- “ation of the spores in the plate will show several in which the very thick wall at the apex is still intact and forms a broad conelike cap *S Bull. Soc. Bot. France §:66. 1889. *4 Essai taxonomique sur les familles et les genres de Hyménomycétes 105- 1900. *S Hymenomycetes Hungarici Kmetiani. Atti Acad. Sci. IIT. 373. 1897. * Bull. Torr. Bot. Club 29:601. 1902; N. Am. Flora 9#:118, 120. 1908. 334 BOTANICAL GAZETTE [NOVEMBER on the spore. As the spore matures and dries, _— oD — on either collapses or breaks off, leaving a“ truncate” or “emargin nd, ; aon spores of P. applanatus of both Europe and the ais — have exactly the same general structure as those of Ganoderma luci described above, as I shall explain in another paper. ag The spores of Ganoderma oregonense Murrill have the x pi structure, but the wall is thinner and the structure 1s mi easy to make out. The form of the spores is also somewhat e a being more nearly elliptical in form, though some are obova — they are slightly larger. In the spores from Ganoderma re ee from Mr. Harp, mentioned above as growing on roots of an a the peculiarities in the structure of the wall described — - G. lucidum and some other species are not well developed, an on demonstrated with difficulty. After several examinations, = the use of the oil immersion lens, I had nearly come to the conc - : that this species was an exception; but after boiling the bee a weak solution of potassium hydrate, the brownish perforati pre the wall were faintly visible. With some other differences e pee character this species seems to be different from the others. ae to present my interpretation of the different species ane add the study of specimens from Europe and the United States, I w1 following diagnoses, : Same. PSEUDOBOLETUM (Jacq.) Murrill,?7 Bull. Torr. ie Club 29:602, 1902. | Agaricus pseudoboletus Jacq. Flor. Austr. 1:26-27. pl. 41. 1773: Boletus rugosus Jacq. Flor. Austr. 2:44. pl. 169. 1774- us lucidus Leys. Flora Halensis 300. 1783. Boletus obliquatus Bull. Herb. France. pl. 7. 1780; pl. 459- 179°: Polyporus lucidus Fries, Syst. Myc. 1:353. 1821. Polyporus laccatus Pers. Myc. Eur. 2:54. 1825. belli- It Ficheli (Nov. Plant Scopout cites. BATARRA in tum Cites Agaricum flabellijorme ena 2 applies to Gen. 118. 1729), which from his own and MicHeEtt’s description ev! some other plant. 1908] ATKINSON—POLYPORUS LUCIDUS 335 Ganoderma lucidum Karsten, Rev. Myc. 3:no. 9, p. 17. 188t. Ganoderma tusgae Murrill, Bull. Torr. Bot. Club 29:60r. 1902; North Amer- ican Flora 9?:118. 1908. Sporophore large, usually stipitate, rarely sessile, annual, rarely perennial, convex above, concave or plane below; pileus dimidiate, teniform, or rarely circular, margin plane or broadly crenate to lobed; surface smooth, sometimes coarsely radiately rugose, incrusted with a reddish or blackish substance shining like varnish, sulcate, the shallow concentric furrows marking off zones which are often narrow and crowded on the margin; trama or context punky, often quite firm and hard especially next the hymenophore, brown to pallid whitish, Whitish above, brown next the hymenophore, zonate especially next the stem, though sometimes faintly; stem when present lateral or excentric or rarely central, long or short, sometimes forked, o.5-4°™ in diameter, even or irregular, sometimes enlarged below, varnished and colored like the pileus, context colored like that of the pileus °r somewhat darker; hymenophore of long slender tubes, brown within, 3-5 to a mm., mouths circular angular, white or yellowish, finally brown, dissepiments entire, obtuse, thin, acute; spores ovoid '0 ovate, rounded at the base and slightly inequilateral in side view; wall hyaline, smooth, thickened at the apex into a broad conelike Cap which usually collapses, leaving the apex truncate or even de- Pressed, everywhere perforate with numerous slender dark-colored €s which radiate from the endospore through the epispore, 9-11 X $8. Fig rt A large and attractive plant, very conspicuous because of its brilliant varnished ‘ppearance. Common on decaying stumps and trunks of frondose and coniferous There appear to be forms or physiological species in this species. In Europe the form more commonly collected is on frondose trees, and is regarded “typical. The usual color of these is a reddish chestnut. The forms cannot be well separated into species, though some of them may : Tegarded as elementary or physiological species or forms. Among these may Mentioned the following: a, - PSEUDOBOLETUM TyPICUM.—On trunks and roots of frondose trees in Europe (also in N. A, ?); color reddish chestnut. G. PSEUDOBOLETUM TSUGAE (Murrill) Atkinson.—On hemlock-spruce (T'suga “madensis) in the United States and British America. Since the form does not STOW on wood of frondose trees in America it may be regarded as a physiological 336 BOTANICAL GAZETTE [NOVEMBER species. In color and other characters it differs but slightly if at all from the typical form. G. PSEUDOBOLETUM MONTANUM Atkinson.—On dead trunks of Abies in the Jura Mountains. This form is very dark, almost black, much darker than the typical form. Type specimens No. 21007 in herb. Cornell University, and a specimen of the same collection deposited in herb. Museum of Paris. Fig. 2. ANODERMA CURTISII (Berk.) Murrill, North American Flora Q?:120. 1908. Ganoderma flabelliforme Murr. p. p. Jour. Myc. 9:94. 1903. Fruit bodies large, corky to woody (sometimes perennial ?), 9.5-3°™ thick at base, with a thin hard crust, margin obtuse; surface zonate, faintly or quite strongly sulcate, sometimes radiately rugose or corrugated toward the margin, smooth, yellowish or reddish yellow, often with reddish spots or zones, not or rarely varnished (laccate); trama or context punky to woody, softer above, harder below next the hymenophore, pallid to pale brownish, light colored next the upper surface; margin sometimes sterile for a short distance on the under side; hymenophore of slender tubes 0.5-1°™ long (of longer), brown in section, pore surface grayish white becoming reddish brown where bruised, tubes 3-7 to a mm., mouths rotund, minute, dissepiments thin, edge obtuse, entire; spores ovoid to ovate, rounded at base and slightly inequilateral in side view; wall hyaline, smooth, thickened at apex into a broad conelike cap, which usually collapses, leaving the apex truncate or even depressed, everywhere perforate with numerous slender dark-colored lines which radiate from the endospore through the epispore, g-11X 5-8 #; stem I-I som long, 13% thick, nearly cylindrical but variable, surface laccate with @ reddish-chestnut varnish on the crust, context brown, nearly ae same color as the tubes or context of the pileus next the tubes. F 18. Sg On dead roots, stumps, etc. of frondose trees in the southern United States: GANODERMA oREGONENsE Murrill, North American Flora 9*+119- 1908.—Sporophore large, stipitate; pileum 14-17°" Jong i broad, 5-5°™ thick, tumid, upper surface rather strongly conver : hymenophore slightly convex or plane; surface smooth, with 4! 1908] ATKINSON—POLYPORUS LUCIDUS 337 brittle crust, shining as if varnished (laccate), dark reddish brown (seal brown to clove brown, R with reddish tinge), sulcate, rings distant on the surface, crowded at the margin, more or less rugose; trama white, cinnamon next the hymenophore, very soft, punky, and yielding like chamois skin, the cinnamon-colored portion firmer; hymenophore of long slender tubes, up to 2-5°™ long, often with a stratified appearance, the strata 3-4™™ and marked off by faint lighter lines, brown, near cinnamon to Mars brown (R), firm, woody, tubes angular, 4~5 to a mm., dissepiments thin, entire; spores elliptical to subovate, rounded at the broader end, in age truncate at the smaller end, attached one side of the broader end, wall perforated by numer- ous short lines of a brownish substance, giving a verrucose appearance to the spore which is really smooth, 11-15 X 7-8 #; stem stout, I-T am X3-6°™, irregular, surface like that of the pileus; trama white, soft like the white part of the pileus, with a radiate, fibrous growth from the middle line and continuing into trama of the pileus. Fig. 4. On dead Picea sitkensis near Seaside, and on dead root (of conifer ?), Cor- vallis, Oregon. Ganoderma subperforatum Atkinson, n. sp.—Sporophore medium ‘ize, stipitate. ileus lateral, simple or lobed, subcircular to reni- form, convex, brick red to bay, vinaceous cinnamon toward margin, and the margin lighter color when young, laccate, broadly sulcate; spores ovate-cuneate, content brownish, wall thin, very faintly per- lorate with slender dark lines, which are seen with difficulty, 8-12 S84. Fig. 5. (Sporophorum stipitatum. Pileo suberoso lignoso, sulcato-rugoso stipiteque laterali, laccato, rubro-castaneo; sporae ovato-cuneatae, membraneo leviter per- *rato ab lineis brunneis, 8-12 5-8 ps.) : On dead oak wood, Chillicothe, Ohio. Type specimen no. 19560 in herb. Cornell University. CoRNELL Universiry EXPLANATION OF PLATE XIX : Photomicrographs . f spores af sev: eral species of Ganoderma, ocu lar die objec- a. oil immersion, Zeiss microscope, plate-holder 370°” a oe the text omicrographs were made by the author. The photog ao agree hor’s figures were produced were made by E. J. PETRY — . . 338 . BOTANICAL GAZETTE [NOVEMBER Fic. 1.—Ganoderma pseudoboletum forma montanum Atkinson, from plant on fir, Jura Mts., France; some of the spores show the entire conical, hyaline cap at apex; note the dark lines perforating the hyaline wall; the upper right-hand spore is in side view, showing at the lower corner a point where the spore was attached to the sterigma; lower spore slightly out of median focal plane, surface appearing roughened or echinulate. ; IG. 2.—Ganoderma pseudoboletum forma tsugae (Murr.) Atkinson, from plant on hemlock-spruce, Ithaca, N. Y.; a few of the spores show: the entire conical cap at the apex; one of the spores of the group in the left is in side view, showing the inequilateral form, and the point where attached to sterigma; note the perforating dark lines in the hyaline wall of the spores; one spore at extreme left slightly out of median focal plane, and these lines appear as echinulations. Fic. 3.—Ganoderma curtisii (Berk.) Murrill; one of the spores at the lower side shows the entire conical cap at apex; this and another one at the left are in side view, showing the inequilateral form; note the perforating dark lines in the hyaline wall; North Carolina plants. 1G. 4.—Ganoderma oregonense Murrill; showing elliptical form of spores, thinner wall, dark perforating lines in wall of spores. IG. 5.—Ganoderma subperforatum Atkinson, from Ohio; showing cuneate form of spores and faint dark lines in the spore wall, only brought out by boiling in potash solution. Fic. 6.—Ganoderma pseudoboletum typicum, from plant collected in Bois de Boulogne, Paris; most of the spores are out of focus; the dark lines perforating the walls appearing as warts or echinulations, but the spores are really smooth. BOTANICAL GAZETTE, XLVI PLATE XIX ATKINSON on POLYPORUS LUCIDUS THE MORPHOLOGY OF PHYLLOCLADUS ALPINUS CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 118 N. JOHANNA KILDAHL (WITH PLATES XX—XXII) The only account of the morphology of Phyllocladus is that of Miss AGNes RoBERTSON (18) in 1906, and this deals exclusively with the anatomical structures and with the affinities of the genus. The material for the present study was collected by Dr. L. Cocx- AYNE of New Zealand. It consisted of two collections: one of ovu- late and staminate strobili, collected November 1, 1906; the other of ovulate strobili, collected December 11, 1906, from cultivated trees. Unfortunately, the two collections did not afford a very close series, and it was impossible to get at some of the most important points, as the development of the microsporangia, microspores, pollen tubes, female gametophyte, archegonial neck cells, ventral cell or nucleus, and embryo. Dr. CocKAYyNE is making collections of the lacking stages at the present time, and it is hoped that a complete description can be presented later. Some material was also obtained from Cambridge, Mass., through the kindness of Dr. B. L. Rosrnson, Consisting of three ovulate cones, taken from the Gray Herbarium and collected on the Wilkes expedition in 1838-1842. At what time of the year these cones were collected is not known, but they showed Somewhat later stages than those of the last collection made by Dr. Cockayne on December 1 1. It is needless to say that this herbarium Material was very much shrunken, and it was impossible to obtain from it any definite structure. Dr. Cockayne’s materia] was killed and fixed in the field, in 7° per cent. alcohol and formalin; cut 5 “and 7 w thick; and stained Part in safranin and gentian violet, and part in iron alum. Staminate strobilus The staminate strobili are formed laterally, in clusters of 2-8 at the tips of the lateral branches. Miss ROBERTSON (18) reports one Staminate strobilus bearing an ovule at its base, which may indicate 339] [Botanical Gazette, vol. 46 340 BOTANICAL GAZETTE [ NOVEMBER that the ancestral condition was bisporangiate. The sporophyll tesembles that of Pinus, although it is comparatively shorter and broader, and has two abaxial sporangia (fig. r). Whether it has any aborted sporangia, as reported in the Taxineae, could not be deter- mined. At least when mature it has fewer sporangia than any of the Taxineae; Taxus baccata having seven, Torreya taxifolia four, Cephalotaxus four to two, and Phyllocladus two. Male gametophyte Material collected November 1 showed the microspores shed and the sporangia wide open along the whole line of dehiscence. Only three or four sporangia retained a few spores, and therefore the sec- tions did not show many stages. The youngest stage found in the development of the microspore was the uninucleate stage (fig. 3), with the wings fully developed. The microspores contain no starch; CouLTER and Lanp (Q) found the microspores of Torreya taxifolia rich in starch; Miss Youne (20) found starch in the spores of Dacrydium; the body cell of Crypio- meria japonica contains starch grains, according to LAWSON : (16) : COKER (7) found the spores of Podocarpus, during all of the divisions, packed with starch, which disappears just before shedding; CHAM BERLAIN (6) found starch in the spores of Pinus Laricio, and Miss FERGUSON (12) in the spores of the species of pine studied by hes. The first division of the microspore cuts off a prothallial - which usually lies against the wall, and which immediately begins 4 disorganize (fig. 6). Soon a second prothallial cell is cut off. Thee two prothallial cells are at first surrounded by delicate walls which very soon disappear, so that when the spore is mature all the Ae nuclei lie free in the common cytoplasm. The first prothallial c : is commonly evanescent and its nucleus soon disintegrates (figs. 9 7 0); in two mature spores it was still recognizable (fig. 11). ices ese prothallial cell always persists, in which respect Phyllocladus 1s — to Ginkgo. Prothallial cells have heretofore not been reported in any scr Coniferales except Podocarpineae and Abietineae. COKE @) Teports two prothallial cells in Podocarpus, one of which a further, while the other slowly degenerates. In Podocarpus — 1908] _ KILDAHL—PHYLLOCLADUS ALPINUS 341 ' Hallii Burtincame (4) finds two prothallial cells, both of which divide and form a tissue, consisting generally of six cells; a similar condition was found in Dacrydium by Miss Youne (16). Two more divisions follow, so that the mature spore commonly contains four free nuclei—prothallial, tube, stalk, and body nuclei. On November 1 the four-nucleate microspores are mostly found lodged on top of the nucellus (fig. 15); how much earlier they reach it and how long they remain there is not known, as no material previous to this date was available. In exceptional instances pollen tubes had been formed and had penetrated the nucellus (fig. 18); but at this date the tube contained only the four nuclei of the mature spore. On December 11 the nucellus was in most cases entirely honeycombed with pollen tubes, and very much disintegrated (jig. 19). The pollen tubes do not pass deviously through the nucellus to any great extent, hor branch, but pass almost in a straight line to the embryo sac. As Many as fifteen tubes were found in one ovule (fig. 19). _ Before the pollen tube enters the embryo sac the body cell divides into two equal and optically similar male cells; it was impossible 'o observe this division, but it takes place some time after the tube has penetrated the nucellus and before it enters the embryo sac (figs. 20, 31b). The entire contents of the pollen tube (five naked nuclei) enter the egg (fig. 20). ARNOLDI (1) also finds that in Cephalotaxus the contents of the pollen tube are emptied into the embryo sac, the contents in this case, however, consisting of only four nuclei; a similar Condition has been found in Pinus, where nearly the whole of the “ontents of the tube is emptied into the cytoplasm of the egg (COULTER and CHAMBERLAIN 10, and FERGUSON 12); according to COKER (8) this may also take place in Taxodium (8) and in Podocarpus (7); and Courter and Lanp (9) report it for Torreya taxijolia. In Ctyptomeria Lawson (16) finds that only one male cell enters the archegonium; and JAGER (13) reports the same in Taxus In Phyllocladus it is not uncommon to find the entire contents of Pollen tubes within the embryo sac after fertilization has taken place, and even after the eight-nucleate proembryo stage (fig. 30); this 0 "= doubt due to the anusial open condition of the archegonia, the Sreatly disintegrated nucellus (which seems to be of a very muci- us Consistency), and the large number of pollen tubes. 342 BOTANICAL GAZETTE [NOVEMBER When the two male cells are equal, it is commonly inferred that both function. So far as could be determined, only one male cell functions in’ Phyllocladus, and the second male cell, together with the other three nuclei discharged into the egg cell from the pollen tube, disintegrate as the proembryo develops, as shown in jig. 26. ARNOLDI (I) finds in Cephalotaxus that the second male cell remains in the upper end of the egg and later goes through a mitotic division. The Taxineae are equally divided in regard to the size of the male cells. In Torreya taxifolia they are unequal (CouLTeR and LAND 9); they are also reported unequal in Taxus by BELAJEFF (3), and by JAGER (13); ARNOLDI reports them of the same size in Ceph- alotaxus (1); and they are equal in Phyllocladus. Outside of the Taxineae they are equal in Juniperus communis (Nor£N 17), Thuja (LAND 15), Sequoia (ARNOLDI 2), Pinus Banksiana (COULTER 11), and Pinus Laricio (CHAMBERLAIN 6). Miss FERGUSON (12) finds them unequal in Pinus Strobus; and one functioning male cell is Teported in Podocarpus by CoKER (7). LAND (13) finds in Ephedra trijurca that the male cells are equal, both enter the egg, but only one functions. Ovulate strobilus The ovulate strobilus occurs on the side of the phylloclad (in the axil of a scale leaf) near its base (fig. 12). It usually occurs sing ys but frequently in pairs; never more than one pair was seen upon @ single phylloclad. The strobilus consists of six to eight rather fleshy scales, each scale bearing a single ovule in its axis. The ovule has two integuments, entirely free from the nucellus to the very base. The inner one is very thick and consists of tas layers: an inner fleshy, a middle stony, and an outer fleshy SR of only two layers of cells. The stony layer begins to develop is of micropylar end and extends toward the base. At first it consists only one layer of cells, but later it becomes much thicker and extends all the way around the base of the ovule, where, however, it seit much thinner than at the micropylar end. ‘The inner fleshy th 1S Somewhat crowded out by the growth of the stony layer; and “as Outer fleshy layer is finally sloughed off. ‘The integument contains vascular strands; these end at the base of the ovule (fg. 15); ve tains a number of resin ducts, shown in the cross-section in fig. 16 1908] KILDAHL—PHYLLOCLADUS ALPINUS 343 The second integument, called an arillus, arises quite late outside of the heavy integument; on November 1 it appears merely as a small papilla in longitudinal section (fig. 15). It grows very rapidly, inclosing the ovule like a cup; the ovule, however, grows up through it, and by December 11 it is merely a light, leathery sheath around the base of the ovule, reaching about half-way to its tip (fig. 14). Female gametophyte It was impossible from the material in hand to ascertain the development of the female gametophyte, as the formation of walls was in most cases well advanced on November 1. In a few instances it was still in the free nuclear stage (fig. 18); and one preparation showed archegonia already formed. The endosperm is of the “rumi- nating” type, this feature being especially pronounced in the early Stages, The development of archegonia could not be observed, as no stage before fertilization was available. It is impossible, therefore, to state definitely whether neck cells are formed or not. Some indefinite Temains of cells, in a few sections, indicate that they exist; and com- paring Phyllocladus with the Taxineae, and taking into consideration that neck cells are often destroyed very early by the pushing-in of the pollen tube or the growth of the central cell, the probability is that a two-celled neck exists in the early stages of the archegonium (fig. 320), although nothing was found upon which a definite statement can be In Torreya taxifolia Courter and LaNp (9) found two neck Cells; ARNOLDI (1) also found two in Cephalotaxus Fortunei; JAGER (13) Teports two in Taxus baccata. From such a condition as that shown in figs. 19, 31, 32, it may be inferred that the presence or absence of neck cells would make very little difference. The whole structure of nucellus and gametophyte is of a very mucilaginous composition, and this, together with the prodigality of pollen tubes and male cells, Presents a very loose and disintegrated condition. The archegonium ', very case, whether located near the surface of the gametophyte or “per in the tissue, presents an opening as large as the width of the Sac. The pollen tube penetrates the tissue, digesting it very readily, and seems to break through the layer of jacket cells surrounding the *mbryo sac as though no obstacle were in its way. No instance was 344 BOTANICAL GAZETTE [NOVEMBER found, at the stage of fertilization, where the archegonium had not been smashed into, either from the top or from the side, by the pollen tube. The embryo sac is surrounded by a layer of jacket cells with very large nuclei, and many of the cells are multinucleate. JAGER (13) also pictures a very heavy jacket layer of uninucleate cells in Taxus baccata; none are reported in Torreya or Cephalotaxus, although the drawings of the latter by ARNOLDI (1) suggest a jacket layer. T he archegonia are one to four in number. No ventral cell or nucleus could be demonstrated, although the probability is that a ventral nucleus is formed; the chromatin in the egg nucleus (jig. 32b) before fertilization indicates that it is getting ready to divide. ARNOLDI (1) says that in Cephalotaxus Fortunei the egg nucleus, shortly before fertilization, cuts off a ventral canal nucleus, which together with a mass of the upper part of the egs destroys the neck cells and passes out of the embryo sac. JAGER (13) does not mention nor picture a ventral nucleus in Taxus; Couns and LAND (9) did not find a ventral cell or nucleus in Torreya taxt jolia; Miss RoBERtTSON (I) interpreted a spindle in the central cell of Torreya californica as the forming of a ventral nucleus. Fertilization At the time of fertilization the egg becomes rich in food vacuoles in the basal end (figs. 25, 26, 28). The egg nucleus may be situated near the upper end of the ege (figs. 22, 23), or near the basal pe (fg. 28). The fusion nucleus (figs. 22, 24) is partially surroundes by the finely granular cytoplasmic sheath of the male nucleus. This cytoplasmic sheath has been observed in Taxodium by COKER @) in Torreya taxifolia by CouLTer and Lanp (9), and in T. calijormics by Miss Ropertson (19). The non-functional male cell (fgs- 22» 23) Which has begun to disorganize, shows the cytoplasmic sheath very distinctly, Embryo The first division of the oospore could not be obtained. Free nuclear division was observed to the eight-nucleate stage- AS — was the oldest stage available, it is impossible to say whether ™ pI free nuclei are formed or not before the formation of walls. sane (I) figures ten free nuclei in one section of Cephalotaxus a 1908] KILDAHL—PHYLLOCLADUS ALPINUS 345 and states that there are eight to sixteen free nuclei. JAGER (13) found sixteen free nuclei in the proembryo of Taxus baccata; and CouLTeR and Lanp (9) found four free nuclei in 7 orreya taxtfolia. One of the older ovules showed a long suspensor and an embryo of a few cells buried near the base of the gametophyte (fig. 33), but it was impossible to make out its structure. Summary The microsporophyll has two abaxial sporangia and the micro- spores are shed on November 1 or before. Two prothallial cells are formed, the first of which is generally evanescent; sometimes both persist as free nuclei, the walls of both being evanescent. The mature microspore has usually four free nuclei, and occa- sionally five, The ovulate strobilus is borne on the phylloclad, and bears two to eight ovules, The ovule has two integuments; one thick and fleshy, the other (arillus) thin and leathery and persistent only at the base. They are free from the nucellus to its base, and contain no vascular strands. Microspores are found resting on the top of the nucellus on Novem- Ft, and occasionally pollen tubes-and archegonia are formed at this date. Pollen tubes are very numerous and pass in a comparatively Straight line through the nucellus to the archegonium. They smash the neck cells, if there are any, and empty their entire contents into the gg; the contents of one or more pollen tubes were found in an egg after the eight-nucleate stage of the proembryo. The body cell divides into two equal male cells just before dis- arge into the egg; and only one male cell functions. The archegonium is surrounded by a heavy jacket layer, consisting of multinucleate cells with large nuclei. Two neck cells are probably fo No ventral cell or nucleus was found, but the material does Not justify a definite statement as to its occurrence or not. The male cell is surrounded by a cytoplasmic sheath which, partly at least, Surrounds the fusion nucleus. At least eight free nuclei are formed by the proembryo before cell Walls are formed; and a long suspensor is developed. ch 346 BOTANICAL GAZETTE [NOVEMBER This work was carried on under the direction of Professor JoHN M. COULTER; and my acknowledgments are also due to Dr. C. J. CHAMBERLAIN and Dr. W. J. G. Lanp, for kindly assistance. Lal ww + i) a - Norén, C, O., Zur Entwickelungsgeschichte des Ju THE UNIVERSITY or CHICAGO LITERATURE CITED - ARNOLDI, W., Embryogenie yon Cephalotaxus Fortunet (Beitrige zur Mor- phologie der Gymnospermen. III). Flora 87: 46-63. pls. 1-3. 1900. 5 , Ueber die Corpuscula und Pollenschlauche bei .S equoia sempervirens (Beitrige zur Morph. der Gym. II). Bull. Nat. Moscou. no. 4. pls. I, 2. I - BEtajerr, W., Zur Lehre yon den Pollenschlauche der Gymnospermen. Ber. Deutsch. Bot. Gesells. I1:196-201. pl. 12. 1893. BuruincaME, L. L., The staminate cone and male gametophyte of Podo- carpus. Bort. GazettTre 46:161-178. pls. 8, 9. 1908. - CALDWELL, Ors W., Microcycas calocoma. Bot. GAZETTE 44:118-14I. pls. To-14. 1907. CHAMBERLAIN, C. J., Oogenesis in Pinus Laricio. Bot. GAZETTE 27:268- 280. pls. 4-6. 1808. CokER, W. C., Notes on the gametophytes and embryo of Podoane Bot. Gazette 33:89-107. pls. 5-7. 1902. ———, The gametophyte and embryo of Taxodium. Bot. GAZETTE 36: t27; 114-140. pls. 1-11. 1903. » Courter, J. M., and Lawn, W. J. G., Gametophytes and embryo of Torreya taxifolia. Bot. GAzerrr 39:161-178. pls. A, 1-3. 1905. - Courter, J. M., and Cuamperxam, C. J., Morphology of Spermatophytes : I - Courter, J. M., Notes on the fertilization and embryogeny of conifers. Bor. Gazerre 23:40-43. pl. 6. 1897. FERGUSON, Marcarer C., Contribution to the knowledge of the life history of Pinus. Proc. Wash. Acad. Sci. 6:1-202. pls. 2-24. I 904. - JAcrr, L., Beitrige zur Kenntniss der Endospermenbildung und zur Em bryologie von Taxus baccata. F lora 86: 241-288. pls. 15-19. 1899. Juet, H., Ueber den Pollenschlauch von Cupressus. Flora 93 pl. 3. 1904. 256-62. - Lanp, W. J. G., Fertilization and embryogeny in Ephedra trifurca- ug GAZETTE 44:273-292. pls. 20-22. 1907. i - Lawson, A. A., The gametophytes, fertilization, and embryo of C77. japonica, Annals of Botany 18: 417-444. pls. 27-30. 1904- i miperus communts. Upsala Universitéts Arsskrift 1907:1-64. pls. I-4. alpinus. - RoBERtson, Acngs, Some points in the morphology of Phyllocladus Annals of Botany 20:259-265. pls. 17, 18. 1906. 1908] KILDAHL—PHYLLOCLADUS ALPINUS 347: 19. ———, Studies in the morphology of Torreya californica. II. The sexual organs and fertilization. New Phytol. 3: 205-216. pls. 7-9. 1904 20. Younc, Mary S., The male gametophyte of Dacrydium. Bor. GAzETTE 44:189-196. pl. 19. 1907. EXPLANATION OF PLATES XX-XXII With the exception of figs. 1 and 2 all the figures were drawn with the aid of a camera lucida and reduced one-half. Index letters are as follows: e, endo- perm; ~, perisperm; #, nucellus; e inner fleshy layer; s, stony layer; of, outer fleshy layer; a, arillus; fs, -— cale TE XX Fic. 1.—Abaxial view of oe showing the empty sporangia. Fic. 2.—Side view of microsporophyll. Fic. 3.—Microspore. 1850. Fic. 4.—First division of microspore. X1850. Fic. 5.—Two-nucleate stage. 1850. Fic. 6.—Second division; first prothallial cell against upper wall. 1850. Fic. 7.—Three-nucleate stage, showing form of wings. X 3000. Fic. 8.—Evanescent walls of the two prothallial cells. 3000 Fic. 9.—First evanescent prothallial cell lying outside of the cytoplasm of the spore. X18s0. Fic. 10.—Mature microspore. 1850. Fic. 11.—Microspore with both prothallial cells retained. 3000. Fic. 12. —Phylloclad with ovulate strobilus. Fic. 13.—Outer view of fleshy scale with ovule. Fic. 14.—Inner view of fleshy scale with ovule, showing arillus Fic. 15, —Longitudinal section of ovulate strobilus, dione ovules with integuments, fleshy scales, and position of vascular system, November 1. X40. Fic. 16. poms geckos of ovule; archegonia in the center of the endosperm; November Tae. Fic. 17 .—Longitudinal section of the ovule with fleshy scales; micropyle not yet formed; arillus covering the ovule; November 1. X40. PLATE XXI Fic. 18.—Part of nucellus on November 1, showing pollen tubes and part of the female gametophyte in the free nuclear stage; archegonia not yet formed; body cell not yet divided. X850. Fic. 19.—Nucellus showing numerous: pollen tubes and open archegonia; nearly all the body cells have divided; December 11. X1 Fic. 20.—Pollen tube, containing two male nuclei, the stalk and tube nuclei, and one prothallial nucleus, entering the archegonium. Sees Fic. 21 -—Archegonial jacket cells. 3000; fig. 214, Fic. 22. Fertilization: the fusing nuclei are saitatly ‘eanmies by the Cytoplasmic sheath; the second male nucleus lies above the fusing nuclei and has n to depenerate. X 3000. 348 BOTANICAL GAZETTE [NOVEMBER Fic. 23.—A later stage in fertilization. 3000 Fic. 24.—F using nuclei with cytoplasmic sheath 1850. Fic. 25.—Second division of proembryo. X30 Fic. 26.—Four-nucleate stage of proembryo; a other four nuclei degenerat- ing. Os ie G. 27. pasion through thick integument showing inner fleshy ae the row of heavy-walled cells (containing crystals) which becomes the stony layer, and the outer fleshy layer of two rows of cells. 1850. PLATE XXII Fic. 28.—Basal end of egg, showing egg nucleus, pollen tube with two male nuclei and one other nucleus, and food vacuoles. 1850. Fic. 28b.—The archegonium of /ig. 28, showing position of egg nucleus and pollen tube in the egg. 100 Fic. 29.—Basal end of aoheye sac, showing four nuclei of the proembryo, remains of the pollen tube, and the non-functional male cell. 1850. Fic. 29b.—Same as fig. 29, showing whole length of embryo sac. X 100. Fic. 30.—Eight free nuclei of proembryo in basal end of sac, with pollen tube above containing normal contents. 1850. Fic. 30b.—Same as fig. 30, showing top of embryo sac. 100 Fic. 31.—Female ey, showing miner by pollen tube; the pollen tube is entering the egg from the side. X 100 Fic, 31b.—Same as fig. 31. X18 Fic. 32.—This figure shows Pag oe path usually made by the po llen tubes through the nucellus to the archegonia. X Fic. 32b.—Same as fig. 32, showing the two srohabie neck cells; structure of the chromatin of the egg nucleus intimates that it may form a ven nucleus; body cell not yet divided. 1850. Fic. 33.—Long suspensor, with embryo buried deep in the female game- tophyte. X 100. the loose tral XX PLATE ANICAL GAZETTE, X1VI san Ca, Rag NF ” rakes ' ‘ t y 6 >, ys — — (<= SSS SE SSS ~ KILDAHL on PHYLLOCLADUS AL GAZETTE, XIVI PLATE XXII AN SS -KILDAHL on PHYLLOCLADUS PLATE XXIV KILDAHL on PHYLLOCLADUS NIGAL GAZETTE, XVI NOTES ON NUMERICAL VARIATION IN THE DAISY C. H. DANFORTH Numerous observers, both in this country and in Germany, have given attention to numerical variations in the ray florets of the Com- positae. For the investigation of the subject the common daisy, perhaps, has been most frequently used. The usual method of study has been simply to count and tabulate the ray florets for a number of heads collected from some prescribed locality. The results of such observations seem to show that the number of ray florets in the daisy is subject to a considerable amount of Variation ; but when a frequency curve ls plotted, more or less definite modes become evident, one on the 21-ray line being especially prominent. With a view to getting more data, I €xamined 4000 heads during the sum- mer of 1905, from which I obtained Tesults that agree in general with those previously obtained by Tower, and by Pearson and YULE from a much smaller number of heads, except that their data do not demonstrate the Presence of a mode on 34, as do my own observations and those of Lupwic (3). a the investigation in question I col- ected 1300 heads from the vicinity of Tufts College, Medford, Mass.; as “sal more from Norway, Oxford : y, Maine; and 1400 from Dennis, ape Cod, Mass. In these lots 12 was TABLE I DISTRIBUTION OF RAYS FOR 4000 ADS COLLECTED AT MED- FORD, NORWAY, AND DENNIS Rays Heads 12 I 13 9 14 + 15 9 16 iz 17 I2 18 25 19 49 20 135 21 423 22 37° 23 205 24 278 25 216 26 ect 27 176 28 ror 29 192 30 184 sr 224 32 218 : 3 266 34 393 35 — 36 47 37 of 38 9 39 3 40 3 the lowest number of rays found in any one head and 4o was the 349] highest. The total number of rays produced by the whole lot was [ Botanical Gazette, vol. 46 350 BOTANICAL GAZETTE [NOVEMBER 107,464, which gives a mean of 26.866 tothe head. The distribution of these rays is indicated in Table I. It will be observed that were these figures plotted the result would be a two-humped curve, indi- cating modes on 21 and 34. If I combine with my own figures those given by Tower (6) and by Pearson and YuLE (4), the resulting table (Table II) will be TABLE I based on a total of 140,988 ray florets DISTRIBUTION OF RAYS FOR 5585 from 5585 heads, collected from five HEADS, BASED ON paTA os- different localities by several different riesgo was doe. PEARSON observers. It may be observed that sookonls this table indicates modes on 21 and 34. — Heads The mean number of rays to the head si - q for this set is 25.242+. These results 23 z coincide with those which have been ne 43 obtained in Germany in that modes 16 7 are evident on 21 and 34; but differ 13 ai from them in that no modes appear ss nae on 13 or 8, the next lower terms of the 21 Stoned es indicating that no essential alteration has taken place in the flowers of our daisy since ™ introduction into this country, but FERNALD (2) has lately called attention to the fact that the common American form is not te typical Chrysanthemum Leucanthemum 1. , but a variety (pi nati dum Lecoq and Lamatte) not usually met with in Germany. — 4 a 1908] DANFORTH—VARIATION IN DAISY 351 sequently the probablity is that all German data are based on the typical Chrysanthemum Leucanthemum, while all American data are doubtless based on var. pinnatifidum. In view of this fact the value of comparisons between the two forms may at first seem doubtful, but a slight further consideration of the character of numerical Variations of the present kind may throw some light on the way m which such variations should be Tegarded. SHULL (5), working with Aster, con- — ae : a. cluded that there is no tendency for FORD BETWEEN May 27 AND all the flowers of the same plant to _ JUNE ™ 1995 TABLE III fall in the same mode, but that those that blossom first have the — es greatest amount of nourishment and therefore ms I show the highest modes. TowER (6) - I Tikewise thought that in the daisy the 16 igher modes are met with early in the 3 3 season, the lower modes later. In se 5 other words, it would seem that these i: 78 authors are inclined not to regard the = 30 Peal modes as indicative of incipient 24 - a My own observations, I think, a 38 Y substantiate their views in this a iE lage A comparison of Tables ag 3 and TV will show clearly a change = 79 ‘ the predominant mode from 34 in 32 Pe in collected between May 34 7 oo. € 14, to 21 in material col- 36 20 prin tween July 3 and July 15. 24 = hough this comparison may not be 39 3 aken as certain evidence, inasmuch as a : = lots were from different local- : » Nevertheless there is a strong suggestion here of a connection Ween mode and season. "hig pairs of tables, one based on material collected at Norway, : oy the other on material collected at Dennis, Mass., ake much T evidence of the relation between mode and environment. 352 BOTANICAL GAZETTE. [NOVEMBER The collections from Norway were taken on June 22, 1905, from the two sides of a private road, about 12 feet wide, which several years previously had been run through an open field. The ground slopes in such a manner that the north side of the road receives practically all of the drainage, while the south side is drier and less favorably supplied. Noticing an apparent difference in the daisies of the two sides of the road, I marked a starting point and picked every head pees SOLS eae within about two feet of the road, till BETWEEN JULY 3 anp Jury 150 had been collected from each side. sla at The table (Table V) based on the TABLE IV counts shows clearly a tendency for the = pa i ide of ie es heads growing on the north si 13 3 the road to have a large number of = é rays, and for those on the south side - 9 to have a much smaller number. This 28 2 difference between the, two lots, tt = a seems to me, may be regarded as he 176 clearly indicating a relations 23 pre the amount of moisture or nutrition ap i 84 the number of ray florets. 26 te - Very similar results were — 28 ed from two lots of 250 heads, oo o &6 lected at Dennis, July 13 and 14. 4? i 31 52 of these lots (Table VI, B) was from res ~ a rosebush tangle near the sea; ; . 38 7s other (Table VI, A), was from a ai 30 ee field near by. These lots pet ; 38 ? show clearly a tendency for e 4 30 2 ing j i d richer s0 39 growing in more moist an % to have a higher number of rays- HH seem [0 These various observations : indicate that the number of ray florets in the daisy is in pat oe tioned by two general factors: an external factor, nutrition; ; another, which might possibly be termed internal, namely, tendency which gives rise to modes. A slight investigation latt , : the the er has led me to believe that. the explanation of and 1908] DANFORTH—VARIATION IN DAISY 353 modes is to be sought in an explanation of phyllotaxis. As is well known, this is a subject which has given rise to a great deal of speculation. Although, perhaps, there is even now no satisfactory explanation of the rules of phyllotaxis, the facts themselves are familiar and only a brief reference need be made to one or two simple conditions. As has been frequently pointed out, TABLE V five-ranked leaves may be regarded as DISTRIBUTION OF RAYS IN Two arranged on the stem according to any ee as Pears pray one of several different schemes. In WAY, JUNE 22, 190s; Lor A one light they may be imagined as FROM SOUTH SIDE OF ROAD; situated regularly along a line coiled Bae gla err spirally around the stem in sucha way that the sixth leaf falls very nearly Rays ae above the first. In this case, if the 6 . line is considered as running around 17 4 the stem in one direction, it encircles . : it twice in passing from the first to a9 zi the sixth leaf; if in the other direction, . 26 5 It encircles it three times in passing en 3 5 between the same two points. On 25 : : changing the point of view slightly, the - 4 ie leaves may be imagined as all arranged a : 3 along two parallel spiral lines running 30 4 # i one direction, or along three similar : 5 2 4 lines Tunning in the opposite direction, 33 ; Pe which case either spiral embraces a te five leaves in each revolution. This < 3 'S equivalent to regarding the leaves 38 as though they were placed at the points [ . of intersection of two opposite sets of Spirals, one composed of two lines, the other of three. Once More, the leaves may be regarded as placed along five nearly vertical but still slightly spiral lines. Of course these are merely different ways of Tegarding one and the same thing. While these conditions, on the whole, are quite constant, never- theless when the stem is increased in diameter or shortened, thereby 354 BOTANICAL GAZETTE [NOVEMBER bringing the leaves or their morphological equivalents closer together, the parts not infrequently become arranged according to an appar- ently different scheme. Thus in the umbels of the wild carrot (Daucus Carota) peduncles are usually so arranged that they seem to be placed at the intersections of what appear to be lines arranged in the form of logarithmic spirals pene (see CHurcH 1), eight running in DISTRIBUTION OF RAYS FOR TWO : B . he other; LOTS OF 250 HEADS EAcH; One direction and five in t : MATERIAL COLLECTED aT DEN- oor, if the umbel is large, eight in one Nis, JULY 13 AND 14, 1905; LOT direction and thirteen in the other. Trou a sosepuss'raxore This arrangement might be considered NEAR BY as differing from the arrangement of eed five-ranked leaves only in the greater Rays Heads ai Sigg ——— number of intersecting spirals. : 2 ief i i resent wf ‘ point of chief interest in the p : . 14 3 connection is that the ani a 16 6 " spirals is confined rather constantly t ithmic os 3 I the lower members of the logarithm! I : £9 3 ; series I, 2, 3, 5) 8, 13, 21) 34 & ar rs 4 If now a daisy head be examin 21 55 27 : : i rhaps 22 27 12 carefully, it will generally a it 2 : ‘ 24 12 = always) be found that the dis a4 28 = ei are so arranged that they appear : = = i ions of two sets a 4 4 placed at the intersections OF © ae 29 ; 2 of spirals; or perhaps they Rok 30 5 15 more conveniently regarded as arta® 4 31 7 28 Ron oo of spira = 5 16 in either of two oppose sae 34 7 o running from the periphery to = c tes = 2 of the head. I shall speak of the a % : though they “ 37 I florets, therefore, as ; peer S ™ ~ arranged in two sets of spirals, t : each of these sets (which one snes ing on the point of view assumed) embraces all the florets. ©" are usually 21 spirals running one way and 13, 21, OF 34 ed the other way. The set of 21 spirals may be either nee ; or right-handed in direction; but in either case the d vie a the spiral is apparently correlated with the arrangement 1908] DANFORTH—VARIATION IN DAISY 355 leaves. Only too plants were examined to determine this rela- tionship, but among these specimens, which were collected at Norway in June, 1908, I found no exception to the rule that the direction of a set of 21 spirals in the disk is similar to the direction of the shortest line that can be drawn from any leaf on the stem to the next succeeding leaf. That is to say, if a stem was ‘so held that any given leaf faced the observer, and it was seen that the next higher leaf on the stem was toward the left rather than toward the right, then a set of 21 left-handed spirals was invariably found in the disk. Of the too heads examined, the 21 spirals were found to be left-handed in 47 cases and right-handed in the remaining 53 cases. Of course the direction of the leaf spirals varied accord- ingly. There can hardly be any indication of incipient species here, for the arrangement on the branches of large plants is, as frequently as otherwise, reversed in reference to the arrangement on the main Stem. I have been unable to trace the transition from the placing of the leaves to that of the flowers, except to notice the above-men- tioned correlation. The ray florets are placed, as one might expect, at the peripheral ends of these spirals. Each of the spirals in the set of 21 generally has a Tay floret at its end; and frequently there are no other rays, specially if the other set consists of 1 3 or 21 spirals. When there are 34 spirals in one set, however, and the head is large, the number of ray florets is frequently increased, when each of the 34 spirals May be terminated by a ray. This case, though common, is less frequent than the other. Instances frequently occur where rays do hot develop at the ends of some of the spirals, or (less commonly) where two rays develop on the same spiral. Heads that show more than 34 rays are of this class. In some of the Compositae, for ‘xample in Erigeron, where the disk florets are arranged in no more Spirals than we find’ in the daisy, there are many rays; but in such fases several flowers of each spiral develop as rays, while in the daisy there seems to be but slight tendency for more than one flower to so develop. If the typical Chrysanthemum Leucanthemum shows as much tendency for developing more than one ray on some of the spirals as °es the var. pinnatifidum, it would seem hazardous to regard any 356 BOTANICAL GAZETTE [NOVEMBER comparison between the numbers of ray florets so far recorded as of taxonomic importance, inasmuch as the variations seem to be merely equivalent to variations in size. In short, the conclusions these observations seem to warrant are: (1) that the florets in the heads of Chrysanthemum Leucanthemum pinnatifidum may be regarded as arranged in either of two sets of spiral lines; or, what amounts to the same thing, in the intersections of these two sets of spirals; (2) that the number of lines in each set is a term of the Fibonacci series; (3) that the number is influ- enced by external conditions, i. e., the conditions of nutrition affecting size; (4) that one set is composed of 21 spirals, which are in some way correlated in their arrangement with the arrangement of the leaves; (5) that each of the 21 spirals and frequently each of the spirals in the other set tends to have a ray developed at its end— hence the modes noted by various observers; and (6) that these facts supply few if any data of taxonomic value. Turts CoLtecE, Mass, LITERATURE CITED 1. CHurcn, A. H., The principles of phyllotaxis. Annals of Botany 18:227- 243. 1904. i . FERNALD, M. L., Chrysanthemum Leucanthemum and the American white- weed. Rhodora 5:177-18r. 1903. ———, AND Rosinson, B. L., Gray’s new manual of botany (under C, Leucanthemum). 7th ed. 1908. 3- Lupwic, F., Weitere Kapitel zur mathematischen Botanik. Zeitschr. Math. Naturwiss. 19: 321-338. 1888. , Variationsstatistische Probleme und Materialien. Biometrika 1+17 29. Igor. hemum Pearson, K., and Yutz, G. U., Variation in ray-flowers of Chrysant Leucanthemum L. Biometrika 1: 319. 1902. © : 5. SHULL, G. H., Place constants for Aster prenanthoides. Bot. GAZE rE 38: 333-375- I904. hemum Tower, W.L., Variation in the ray flowers of Chrysanthemum Leucant! es L. at Yellow Springs, Green Co., Ohio, with remarks upon the determin of nodes. Biometrika 1: 309-315. Ig02. Nv - e . THE VASCULAR ANATOMY OF THE SEEDLING OF DIOON EDULE CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY IIQ REINHARDT THIESSEN (WITH PLATES XXIII-XXIX) This investigation was begun durin g the winter of 1906, the original purpose being to clear up the confusing statements in reference to the So-called girdling habit of the leaf trace. As the work progressed, its scope became extended, until finally it included all of those ana- tomical features of the seedling that have a bearing upon the relation- ship of the Cycadales to the Cycadofilicales and Filicales. I wish to express my appreciation of the constant encouragement Teceived at all times from Dr. Joun M. Coutter, under whose direc- tion the work was carried on ; Lalso wish to thank Dr. C. J. CHAMBER- LAIN for kindly furnishing the material. Historical : The first work on Dioon edule was by Metrentus (4), who com- Pared it with Cycas revoluta, which was the special form investigated. The methods of those days (1861) did not permit tracing the various vascular bundles throughout their course. Sections were cut only here and there, and the large number of bundles presented only a very incomplete and vague idea to the investigator, resulting in com- Plete misapprehension. The picture of the leaf trace girdle as METTENIWS drew it is in the main as follows. A bundle in its course toward a leaf divides soon after leaving the central cylinder, the two branches in turn soon dividing. These branches and branchlets, in the main retaining their radially ascending direction, but running at various angles, anastomose mith one another and with branches of neighboring bundles, and nally unite with bundles which girdle the vascular cylinder. This Sirdle lies closest to the ring at a point diametrically opposite the leaf € which its ends enter, each of which therefore traverses the cortex through an arc of about go°, gradually separating farther from it and 357] [Botanical Gazette, vol. 46 358 BOTANICAL GAZETTE [NOVEMBER finally entering the leaf base. There is such a girdle for every leaf, and every girdle must cut, on account of its course and location, every other like girdle in two places. Every girdle receives on its inner edge branches from the central vascular bundles which leave the vascular cylinder at various places, and sends out branches from its outer edge to other girdles. From this vague conception, which does not at all agree with the drawings of METTENTUS, the current text- book accounts have been drawn. These accounts, however, do not really interpret METTENIUs, but are as far from his interpretation as that was from the true situation. In his description of the structure of the bundles METTENIUS was more fortunate, and made a very important contribution. He says that those bundles which are to leave the vascular cylinder are marked off by broad medullary rays and are more definitely bounded than those which continue in the cylinder; that on the inner edge they are provided with spiral vessels (protoxylem), while the others are Pro — vided with reticulated cells in the same relative position. At the region of the outward bend of the trace the vascular elements are grouped with the spiral elements on the inner or upper side, immediately bordering the reticulated elements beneath; and this structure the girdle retains in encompassing the stem. Before entering the leat, however, a change in structure begins to occur, and is completed in the lower part of the petiole; after which the bundle remains un- changed up to the pinnae. The first indication of this change the appearance of thin-walled cells in the vicinity of the spiral (pr ey lem) elements, separating them from the reticulate elements. 8 the further course of the bundle the spiral (protoxylem) seit gradually move farther within, and the wood is now divided into ui parts by the thin-walled cells; the inner part developing its elemen = constituents centripetally, and the outer part centrifugally. #1 the spiral (protoxylem) elements are found in the outer part be bundle, and the centrifugal part is still more reduced, while centripetal part has reached its maximum development. This oe ture of the bundle is retained in its further course in the petiole = in the pinnae, where in Dioon edule the centrifugal wood is a altogether. Such is a very brief statement of the descriptio? i os transition from centrifugal to centripetal xylem in the leaf tac the the 1908] THIESSEN—DIOON EDULE 359 given by METTeNrus. It was the first correct statement of the facts, but their meaning was probably not understood until an interpreta- tion of the situation was given in 1886 by BERTRAND and RENAULT (5). The second paper upon the vascular anatomy of Dioon is that of Matte (6), a brief description of the anatomy of two seedlings being given. In one of them, a very young seedling, the cotyledons were unequal, the larger having four vascular bundles, and the smaller having two small bundles, but with two other very small strands at the very base, one on each side of the other bundles. The bundles con- tinue in a vertically descending course until where the foliar bundles, alter being arranged in a circle, have been reduced to four large bundles, separated by medullary rays. The six cotyledonary strands turn now abruptly toward the three poles (protoxylem groups) of the root, converge, and unite two by two in front of them, effecting an entrance through the medullary rays separating the foliar bundles, and unite their phloem with the phloem of the stem. Their second- ary xylem unites laterally with that of the stem, while the primary Xylem seems to be in direct continuity with the tracheal poles (pro- toxylem groups) of the root. The centripetal xylem disappears in the Passage across the medullary rays. In the description of the older seedling Matte found in each cotyledon four bundles of equal size. Their course and method of union js comparable with that found in the other seedling, and they still unite two by two in converging toward the poles (protoxylem 8roups), but these poles are four in number. _ Marte touches also upon the girdling habit, ascribing it to an itercalary growth produced under the influence of the development of new interior leaves. The vascular strands of the youngest leaves Pursue a vertical course, but those of the older ones an oblique Souitte, a comparison of leaves of different ages showing that this departure from a direct course is due to intercalary growth. Methods Embryos were removed from mature seeds and killed in chromo- acetic acid, imbedded in paraffin according to the usual methods, s with a rotary Minot microtome, and mounted in series, much care “ing taken that no sections were lost or misplaced. When only the 360 BOTANICAL GAZETTE [NOVEMBER location or outline of the bundle was wanted, the cross-sections were cut 20 to 30 # thick; in other cases they were cut 10 # thick. Longi- tudinal sections were cut at right angles to the inner surfaces of the cotyledons, as well as parallel to that plane; these were cut 10 # thick. Staining was done on the slide with safranin and Delafield’s hema- toxylin, or safranin and anilin blue. Other stains were tried, but these two combinations gave by far the best results. A few speci mens were killed by the general picro-mercuric-chlorid method, but no advantage was gained. Where seedlings were required, the hard coats of the seeds were cut partly open at the micropylar end, and the seeds placed on one side, partially pressed into moist earth, in a flower pot, and put na warm moist place in the greenhouse and kept well watered. A good many seeds had been planted three years before and had grown to considerable size, some of them having a stem 1oo™™ in length and 25™™ in diameter, and bearing several leaves. These were treated about as the embryos, except that all the specimens were cut into lengths of 15 to 20™™, Of course the greater the size of the plant the more slowly the processes of killing, washing, embedding, etc., were conducted. Especial care had to be taken in imbedding the larger specimens, the best results being obtained when they vor carried through the process of penetration with paraffin for a whole month. After this time they could. be cut with an ordinary Minot rotary microtome with perfect ease, and the sections could be held in complete ribbons. After this precaution, ribbons were obtained from specimens 26™™ in diameter and cut 10 thick. Staining was = as before with safranin and Delafield’s hematoxylin, or safran gis anilin blue, the former combination giving the most satisfactory results. An enormous amount of labor is necessary and in much care to keep sections of entire plants in serial order, both cross and longitudinal sectioning, but it is the only satisfactor) method In order to obtain the details or to follow up the leaf trace course every section was examined, from the first to the last, and ¢ fully drawings made of ev ery second or third section. These re jons numbered and kept in series and later compared, and recons see were based upon them. 1908] THIESSEN—DIOON EDULE 361 Observations THE EMBRYO EXTERNAL STRUCTURE.—In the mature seed the cylindrical embryo is fully two-thirds as long as the endosperm, averaging 20™™ in length and about 4™™ in diameter. The hypocotyl (fig. 1) is comparatively very short, being about 5™™ long, ends abruptly (very often is even concave), and in the center is still attached the slender, very much twisted and coiled suspensor (s). The cotyledons are free for the upper four-fifths of their length, the lower fifth forming a tubular sheath (sh) inclosing the leaf primordia (figs. 2, 3). One of the cotyledons is slightly larger than the other, and is inserted a little lower on the axis, slightly enfolding the smaller one. There are generally two leaf primordia, but sometimes three. The broad base of the outer or older one (Lx) embraces the inner and next younger one (L,), which in turn often embraces a third (L,); and finally beneath them all is the stem tip (sé), On the oldest leaf primordia are all the rudiments of the pinnae (fm) of the future leaf quite well advanced; while no indication of them can be detected on the younger primordia. To understand certain features to be described later, it is necessary to note the arrangement of the earlier leaves. An older plant (fig. 7) may be used as an illustration, and both scales and foliage leaves will be spoken of as leaves and numbered from r to g according to age. The cotyledons (cof) are apparently exactly opposite; z and 2 are approximately opposite, but close observation shows that they are not exactly so; also 1 and 2 are approximately at right angles to the Cotyledons (also fig. 2). The sheathing leaf base of z is a little longer and more slender on the side toward which the spiral turns, and folds around the inner leaf or scale a little farther than it does on the other side. Leaf 3 lacks still more of being opposite 2; also the Corresponding edge of the sheathing base of 2 is more slender and folds over 3 more than its fellow. Leaf 4 lacks still more of being *Pposite 3, and again the sheathing base is more slender and folds ‘found the next inner leaves more on that side toward which the ‘piral turns. In the rest of the series the spiral is uniform, and the *verlapping more conspicuous. - ANTERNAL stRUCTURE.—The bulk of the embryo is of course 362 BOTANICAL GAZETTE [NOVEMBER parenchymatous, and the general structure is shown in jigs. 2-6, 8, 9; 29-35. The epidermis (ep) consists of large, regular, isodiametric cells with large nuclei. That of the cotyledons is abundantly supplied with stomata on the exterior surface of the tubular part and a small portion of the lobes. No stomata occur on the part of the cotyledons remaining in the endosperm, on the interior surface of the cotyledons, or on the primordia. The epidermis of the petioles and bases of the leaf primordia is covered densely with long, unicellular hairs, with well-defined nuclei (figs. 28, 29). The ground tissue is composed of long, regular, prismatic cells, much longer than wide in the cotyledons, but shorter and more isodia- metric in the stem proper (figs. 3, 8). At the lower extremity of the embryo the cells lose their nuclei, become filled with a dense material, and form a hard capping tissue (cp, figs. 3, 28, 29)- Distributed irregularly in all parts of the ground tissue are many cells, cavities, and canals filled with mucilage (m, fig. 8; black spots in jigs. 28-35). The cavities are found most abundantly in the cotyledons and are formed by the disorganization of several neighboring cells. The canals, which are formed by the disorganization of the cells end to end, forming tubes of limited length, are most abundant in the petioles of both cotyledons and leaves. The vascular cylinder is very short, the length being much le the diameter, and hence it is usually called the vascular plate (P ) It is squarish, one diagonal diameter being approximately at right angles to the inner faces of the cotyledons, and the other parallel with them. The xylem (figs. 32, 33, *), consisting at this stage probably of protoxylem only, is surrounded by a zone of phloem (ph). The xylem is compact and well developed where it borders the phloem, but toward the center it is gradually mixed more and more with pith cells, till in the center the xylem elements lie scattered among the pith cells, these scattered cells being very short and irregular. ©" condition varies in different specimens, in some the xylem being se Coppers the center, while in others it is entirely wanting a Tegion (fig. 32). The protoxylem groups——At each corner of the sq Plate there is a group of protoxylem elements (P%), ss than uarish vascular 3 which in cross- 1908] THIESSEN—DIOON EDULE 363 section is irregularly oval. These four groups extend downward for a short distance, where they form the protoxylem of the primary root (a, figs. 4, 5, 8). The potential vascular tissue.—Above the vascular plate there is a conical or dome-shaped mass of tissue terminating in the growing point of the stem, sharply marked off from cortex and pith, and con- sisting of long, irregular cells with dense protoplasm and prominent nuclei. The frequent occurrence of mitotic figures shows it to be the most active meristematic region of the stem; being the tissue in which the vascular strands are developed, and therefore the procam- bium (pc, figs. 8, 34, 35). The pith in the vascular plate contains scattered and short xylem elements (x, jig. 8), as stated above. Above the plate it is conical and terminates in a tier of cells against the epidermis (7, fig. 8); in this region the cells are thin-walled and very irregular. In all the pith mucilage cells and cavities are abundant. The vascular strands:—All the vascular bundles are collateral, €xcept in the upper part of the cotyledons, where they may be regarded a8 concentric. In the leaf strands the collateral bundle is surrounded by a sheath, which is not well-defined. In the younger strands the few elements are protoxylem, and new elements are added centrifu- gally (endarch), centripetally (exarch), or in all directions (mesarch). The bulk of the bundle is as yet procambial tissue (compare figs. 10-15 and 16-21 with figs. 22-25). In the older strands it is difficult, if not impossible, to determine where protoxylem ends and metaxylem begins, The vascular strands of the cotyledons (figs. 4-6).—From each of the four protoxylem groups in the vascular plate (px) a strand runs Sutward for a short distance and then branches, the branches “eparating at wide angles and continuing outwardly in a horizontal Plane until well under the bases of the cotyledons, where they turn abruptly upward into the cotyledons, thus giving four strands to ach cotyledon, and in such a way that each of the opposite protoxylem Soups on the diagonal perpendicular to the inner faces of the cotyle- ns gives rise to the two inner strands of each of the cotyledons; while ach of the other two protoxylem groups gives rise to the outer strands °f the cotyledons in opposite edges, that is, one branch goes into the 364 BOTANICAL GAZETTE [NOVEMBER edge of the cotyledon on one side, and the other branch from the same protoxylem group into the corresponding edge of the other cotyledon. This may be stated in another way. In tracing down- ward, the four strands of each of the petioles of the cotyledons may be said to join two by two. Just before reaching the central cylinder the inner strands of each fuse, and the outer strands of the one fuse with the outer strands of the other, the four strands thus formed giving rise to the four protoxylem groups. This is shown semi- diagrammatically in figs. 4-6. Tracing these strands farther upward, they are found to branch once more, so that in the upper part of each cotyledon there may be as many as eight strands; but before reaching the tips of the cotyledons they reunite into one concentric bundle (fig. 15), which abuts immediately against the epidermis, thus com- ing into very close contact with the gametophyte. At this place the tissue of the gametophyte is so closely attached to that of the cotyledons that it is difficult to separate them. The vascular strands of the leaf primordia.—For each leaf or leaf primordium four strands leave the vascular cylinder or vascular plate, at points not definitely located, but quite well distributed, and generally in such a way that approximately one strand for each leat or primordium leaves on each side of the squarish central vascular cylinder; also those strands belonging to the first leaves have their origin either in the neighborhood of or in the protoxylem groups of the plate. Two strands leave the cylinder approximately oD ~ Same side as that on which the leaf for which they are destined 1s located, and run more or less directly through the cortex into the ven" tral part of the petiole without further branching; while the oth “ two strands leave the central cylinder approximately on the opposite _ Side and describe a curve around it (the one in one direction and the other in the opposite direction) through the cortex, through the sheath- ing leaf base, and finally into the dorsal or adaxial part of the petiole, where they branch and rebranch ( figs. 4-6). It should be empha sized that the point of origin is not at all definite, and that any pau lar girdle does not describe an arc of any definite extent, but i = length of the arc depends upon the place of origin of the girdle " the position of the leaf to which it belongs. aoe It has been said that that edge of the leaf base toward which t 1908] THIESSEN—DIOON EDULE 365 spiral turns is more slender and folds over the next inner leaf more than does its mate (fig. 7). It will be observed that the girdle which is destined for that side of the leaf generally describes a longer curve through the cortex than the one destined for the other side. The phenomenon of girdling will become clearer when illustrated by a specific case. In fig. 6, taken from a young seedling, L:, L,, L,, and L, represent the first, second, third, and fourth leaves or primor- oa Lt, L?, L3, L4, the four strands of the first leaf; Li, L2, L3, L4, the strands of the second primordium. Lz? is the longest girdle of the first leaf and has its origin at the protoxylem group px’, on the side directly opposite the leaf to which it belongs, ascends for a short distance, then turns outwardly into the cortex and describes a wide horizontal curve, enters the longer and more slender edge of the leaf base, and ascends in the petiole in the dorsal left-hand portion, branching repeatedly in its further course. Trace Ls leaves the cen- tral cylinder near the protoxylem group px‘, ascends a short distance, Tuns upwardly and outwardly into the cortex, describes a horizontal curve in the opposite direction, enters that side of the leaf having the shorter sheathing base, ahd ascends in the dorsal or adaxial portion of the petiole, where it branches repeatedly in its further upward Course. From this it will be seen that the leaf trace L} pursues a longer Course than trace L+. Trace L? has its origin near the protoxylem Stoup px3, to the left, ascends for a short distance, runs out into the Cortex, makes a very slight horizontal curve (almost direct) into the leaf base, running outwardly, and then ascends on the ventral or abaxial left-hand portion of the petiole without further branching. Trace Ls has its origin near the protoxylem group px‘, ascends for 4 short distance, runs outwardly (gradually ascending) with a slight curve into the leaf base, and finally ascends in the ventral or abaxial night-hand portion of the petiole without further branching. It will be seen that in the case of the two inner strands L3 makes a girdle of about 90°, while trace L? is approximately direct. bout the same condition occurs in the traces of the second leaf. Trace L} has its origin to the left and near the protoxylem group Px, ascends vertically for a short distance (but farther than the ‘trands of L,), runs a short distance outwardly into the cortex and then makes a wide horizontal sweep, enters the leaf base on that side 366 BOTANICAL GAZETTE [NOVEMBER which ensheaths the younger primordium with its more slender edge, ascends in the petioles on the inner or dorsal portion, and branches repeatedly. Trace L, has its origin near and to the right of the protoxylem group px?, describes a girdle of approximately the same magnitude as girdle L4, and runs into the base of the leaf on the right hand. Traces L? and L3 have their origin respectively on the right and left of the protoxylem group px? (quite close to it), and after ascending for a short distance run directly into the outer or ventral portion of the leaf, where they ascend without further branching. These facts seem to indicate that there is some relationship between the protoxylem groups of the vascular plate and the origin of the trace of the first leaves. The traces of the third leaf (L,) are followed with some difficulty, but the same condition noted for the first and second leaves is clear. When a fourth leaf is far enough advanced, exactly the same conditions are also presented. The girdling habit of the very young strands is already marked out; but their origin appears no longer to be restricted to the neighborhood of the protoxy- lem groups, but may occur anywhere in the plate, from which they how ascend vertically for a longer distance before turning out into the cortex. It is very difficult, however, to follow the younger strands while they are still in the potential vascular tissue, since no xylem elements have as yet been formed; but in their passage through the cortex into the primordium their path may be made out clearly, and It shows that the girdle is already established at this stage. Even ™ the absence of xylem elements, the bundle is clearly marked off by the character and arrangement of its cells (jigs. 26, 27). Although the specific case described represents the general state of affairs, many variations are found in the place of origin of the trace. Of the many specimens examined probably no two traces were foun i be exactly alike in this respect; also anastomoses between adjoin- ing traces were found here and there. The strands thus ascending vertically for a short distance into the procambial tissue above the vascular plate are the first to assume specific characters. Although - ce cylinder is made up of separate traces, it must be observ’ at these are in the procambial tissue, which is very different from that which surrounds the procambium. The transition from endarch to exarch xylem.—When 4 cotyle: 1908] THIESSEN—DIOON EDULE 367 donary strand leaves the vascular cylinder it is endarch (fig. 10). As it passes upward and outward, the protoxylem elements recede from the endarch position and are buried more and more in metaxy- lem, that is, centripetal wood has appeared. When well up in the tubular portion of the petioles of the cotyledons, the protoxylem is surrounded equally on all sides by metaxylem, the xylem being typically mesarch (figs. 11-13). From this point on the protoxylem approaches more and more an exarch position, but the xylem does not become completely exarch. Before the end of the bundle has been teached it has become quite concentric, and it becomes very difficult to determine which element was the first to appear (fig. 15). Where the bundle leaves the central cylinder the total xylem elements so far as developed are at the innermost part of the bundle, and as the bundle is traced upward they recede from that position and occupy one farther inward, until in the upper extremity of the cotyledon they occupy a position central to the whole bundle. Thus the trans- Position of the total xylem holds the same relation to the procambium as the protoxylem holds to the metaxylem (fig. 9, @). The leaf traces also when leaving the vascular cylinder are endarch (fig. 16), and in passing outward and upward the protoxylem ele- ments recede from the inner edge and are buried deeper and deeper in the metaxylem; and well up in the leaf bases the xylem has become Mesarch (figs. 18, 19). Afterward the protoxylem approaches more and more an exarch position, until at the transition between petiole and leaf base the xylem has become completely exarch, with the pro- toxylem lying immediately against the procambium (jigs. 20, 21). There is at this stage no centrifugal wood above this point; and there ‘So secondary wood anywhere. The transition may be said to occur, therefore, between the central cylinder and the leaf base, from which Point upward the strands are all exarch. It must be taken into Consideration that none of the leaves are as yet fully developed, only the first leaf showing plainly the different regions (jig. 3). Fig. 9,4 ‘epresents the situation diagrammatically. It will be observed that only a very small part of the procambium has been developed into xylem tissue in the whole length of the petioles (figs. 7 6,17). Cross-sections of foliar strands at a low region show, besides the protoxylem and centrifugal metaxylem elements, a pro- 368 BOTANICAL GAZETTE [NOVEMBER cambium stretching more than half-way across the bundle, the boundary being marked by a thicker-walled tissue, the protophloem. Higher up in the bundle the centrifugal procambium decreases proportionally as the protoxylem moves outward. Figs. 4, a and 21 show the situation more clearly; both are taken from very young primordia, the latter much younger and higher up than the former. In fig. 21 the xylem elements are approximately in the center of the bundle, but there is still considerable procambium between them and the protophloem. The cambium appears to be developed later, just inside the protophloem, and develops tissue actively toward the phloem side only. THE SEEDLING EXTERNAL STRUCTURE.—When the seed of Dioon germinates, the hypocotyl pushes through the micropylar end of the seed, where there is at this time an area in the testa, about the diameter of the embryo, which softens readily and is easily penetrated by water. If left to itself, this process takes from a week to a month, and sometimes longer; but if the area referred to is cut away, the hypocotyl pushes through in a few days. During germination the whole of the hype cotyl and the lower part of the cotyledons lengthen. As soon as the hypocotyl reaches the soil a tap root is sent deep into the ground, and before any leaves appear the root may have penetrated the soil 8 to 12°", and the diameter of the hypocotyl may have increased to about 1°™, After a long period (which in Lp greenhouse was about four weeks in case the micropylar end was cut away,'but many months if it was not) the first leaf appears betwee? the cleft of the cotyledons, in direct continuation of the axis. As M7 natural position of the seed during germination is horizontal, and wid hypocotyl bends down approximately at right angles, the leaf pushes forth where the cotyledons make a sharp bend. The cotyledons remain in the seed, and in seedlings three or four years old the may be seen still attached to the plant. At this time also lateral roots appear in four rows along the primary root, corresponding ad the four protoxylem groups. : A second leaf does not appear until perhaps a year later, an about another year elapses before a third appears. A pl oe 1908] THIESSEN—DIOON EDULE 369 age has developed about nine or ten leaf primordia, but only about one-third have developed into leaves. INTERNAL STRUCTURE.—During germination, in connection with the development of the primary root, not all of the tissue of the tip of the plantlet resumes growth, but only the plerome and a limited portion of the periblem or cortex surrounding it becomes meristem- atic and pushes through the hard and caplike tissue at the tip of the embryo. The cortex which does not resume growth, as well as the caplike tissue, frays off (fig. 9, jr). Also, as growth progresses, the outer layers of the newly formed root, some distance back of the Toot tip, keeps on fraying off; and underneath a phellogen soon appears and a layer of cork several cells thick is formed. Along each of the four protoxylem strands of the root, continuous from the vascular plate, lateral roots have their origin at definite intervals, being arranged in four rows. Certain cells among and near the Protoxylem elements become meristematic, and form the tip of the lateral root, which pushes through the cortex. The vascular cylinder increases in dimensions uniformly with the growth of the seedling as a whole. New bundles are inserted as new leaf primordia appear, and gradually fill in more and more the vacant spaces between the original strands, so that immediately above the original plate the vascular cylinder is quite compact, while beyond this it continues to be represented by separated strands in the potential vascular tissue. The vascular strands of the cotyledons.—Not much need be added 'o the statements in reference to the cotyledonary strands. The transition from endarch to exarch xylem is very much more gradual and the mesarch stage is located relatively much farther up. This S due to the fact that most of the growth of the cotyledon in length Sccurs at its lower extremity. No secondary wood is developed in cotyledons. The phloem also has increased in bulk, but mature sieve tubes are never developed. : The leaves and scales.—As said above, not all the primordia de- Velop into leaves, most of them remaining abortive and forming scales. hough about one-third of the primordia develop leaves, it does not follow that every third primordium becomes a leaf in regular succes- Sion. It sometimes happens that two leaves are developed from 370 BOTANICAL GAZETTE [NOVEMBER consecutive primordia. Evidences indicate that a scale is not pre- determined, but remains abortive through some variable cause. The primordia, whether developing scales or leaves, show the same struc- ture in every particular. The leaf traces.—The course of the leaf traces in the seedling are the same in general plan as those described for the embryo, but the girdling in the older leaves and scales is much more marked. The internal growth and the appearance of new organs has crowded the older parts farther and farther outward. ‘The circumference of the cortex has increased materially, and also the length of the vascular strands running through it. In the older scales and fully developed leaves these are all of about the same extent, and almost horizontal; but from these, through the younger leaves and scales to the youngest primordia, the sweep of the girdle diminishes; but the girdles are anes established in the very youngest of the primordia (figs. 34, 35) 8-) : Although in the strands of the youngest leaf primordia no xylem elements are present, the courses of the bundles may be made out readily because of the arrangement, the staining qualities, and shape of the cells, which have denser protoplasm and larger nuclei, and are longer than the adjacent cells (figs. 26, 27). ‘The strands of the very youngest primordia which have their origin on the opposite side of the central cylinder show the girdling habit in the same manner - those of the older leaves, but on a smaller scale. The girdle does not always take the horizontal direction, but may be more oblique at the beginning (figs. 4, 5, 34, 35). Fig. 35 shows this clearly, in which pc is the procambium and lig the girdle of the youngest primordium. So long as such a strand is outside of the procambium it can be followed easily, but is lost after it has entered it. In the oldest plant examined (three or four years old); the firsts second, third, and fourth leaves displayed exactly the same — si was shown in the young leaves of the embryo and seedling. ag in the older leaves, outside of these, it is impossible to determine whether the described order is retained, because of the difficulty ™ following up strands of such size; but it is certain that anastomos are more frequent, due to the close proximity of crossing bundles. The transition of the xylem.—The strands of the older leave its 1908] THIESSEN—DIOON EDULE 371 a larger development of metaxylem; also secondary wood may have developed in the lower extremities, so that the transition from endarch to exarch has become more prominent and can be made out with greater clearness. The secondary wood accompanies the bundle as yet only for a short distance, and ceases long before the transition from endarch to exarch is complete. As the secondary xylem and centrifugal metaxylem diminish, the centripetal xylem (which of course is all primary) increases in bulk (fig. 9, a). Ina plant three years old no other secondary wood was present (figs. 22, 23). Even in the oldest leaves of quite old plants the secondary wood, which at the origin of the strand is quite massive, decreases very rapidly, and in the petiole just above the leaf base has thinned out to a few elements (ig. 24), remaining quite uniform to the rachis, where it disappears still more; while in the pinna no secondary wood whatever is present, all the xylem being primary and centripetal. Although in the transi- tion region the secondary wood diminishes in the same ratio in which the Primary wood increases, it must be noticed that the centrifugal Wood is not restricted to the secondary wood alone, as was shown in the younger bundles of the embryo, where the transition is clearly Carried out in the protoxylem and metaxylem alone. Thus in the seedlings the transition from centrifugal to centripetal wood is carried a after the appearance of secondary wood, and is completed in the Primary wood. In the older strands where secondary wood has been developed, a Considerable amount of the centrifugal wood therefore is metaxylem. This is shown by the amount of procambium that has been developed into centrifugal xylem; as may be seen by comparing the younger Strands in figs. ar, 4, a, for example, where there is a certain amount of centrifugal procambium, the amount depending upon the distance om the point of egress from the central cylinder, with the older Strands in fig, 24. Sometimes all of the centrifugal procambium aS become xylem; more often, however, patches of procambium T isolated cells of it are never lignified and retain their nuclei, and are then referred to as the thin-walled cells. These m-walled cells do not necessarily lie against the secondary Wood, though they most often do, and become most evident the upper extremities of the transition. A series of cross- 372 BOTANICAL GAZETTE [NOVEMBER sections of a maturer leaf of a seedling clearly shows the transition from endarch, through mesarch, to exarch, and shows that it is quite independent of secondary wood. The transition begins at the point where the strand leaves the central cylinder, and in the seedling pro- gresses uniformly and is completed in the petiole; but in the old plant the larger proportion of the transition is completed in the lower part of the petiole, where only a few strands of secondary xylem remain and continue uniform until the bundles enter the pinna, when the transition is completed (fig. 25). The cause of girdling—No particular cause has been assigned for this phenomenon. If such a leaf primordium as is represented in figs. 3, L,, and 8, L, be selected, it is possible by careful staining to detect four strands which are ultimately developed into vascular bundles. The outer (abaxial) ones pursue a more or less direct course, but in following them from the stem up, their course at first, after leaving the procambium, is vertical; but in the base of the primordium they turn inward to a considerable extent (fig. 3, L,). The two innet or adaxial strands after leaving the procambial cone pursue quite a vertical course, but on reaching a region at the level of the base of the primordium, they begin to turn toward it, one on each side, in some cases ascending rather obliquely, but generally horizontal from the start. Figs. 34, 35, ligt shows the girdling of quite a young primor dium, the youngest one in that specimen. It is plain, therefore. ” the girdle is established very early in the development of the leaf to which it belongs. Tracheae.—In examining older plants, the oldest one being ght or four years old, a singular phenomenon is noticed. eines com- various bundles of the stem, which at this time do not yet make a plete ring, vertical connections are found, consisting of i reticulated elements, branching and anastomosing, but forming a tinuous vessels. In the upper part of the plant, where they are 4° oping, long and narrow cells are found winding and crowding t a between the parenchymatous cells. A little farther down ” smi parts of the stem, these cells are found to be multinucleate, with os here and there an ill-defined cross-wall. A little farther dows sual nuclei disappear, and soon lignification appears, developing into well-defined reticulated tracheae. ‘These wind in a very t b] 1908] THIESSEN—DIOON EDULE 373 way vertically through the parenchymatous cells from one bundle to another. They are in all senses true reticulated vessels, without cross-walls, establishing a connection between the bundles of the vascu- lar system. Discussion In the embryo of Dioon edule the vascular cylinder is a protostele, which in.some specimens contains a solid xylem mass. From this solid cylinder all gradations are found to the siphonostele. The cells of the pith are actively meristematic, as shown by the mitotic figures, and often in older specimens xylem elements are found in the central Part at the level of the vascular plate. The xylem cylinder also con- tinually increases in size, new elements being added to it constantly between bundles already existing, as well as by the cambium. It should be emphasized that the vascular cylinder in the embryo and seedling does not consist of the short xylem cylinder only, but is continuous in a tissue, very different from the cortex outside and the pith within, which gives rise to strands of procambial tissue running into the leaf primordia. The pith is also a well-defined tissue from the vascular plate to the stem tip, and nowhere suggests that it arises 6M an intrusion of the cortex through the leaf gaps. An inspection of fig. 8 shows that it has its beginning at the very tip of the growing Point, where it is seen to consist of a single row of cells or a tier of a few cells, gradually expanding as the stem grows into the large pith found in the older part. The transition of the protoxylem from the endarch to the exarch Position was first described by Metrentus (4), who also suggested the descriptive terms centripetal and centrifugal xylem. The situation "as interpreted by BERTRAND and RENAULT (§), who also established that the centripetal wood is in the same relative position throughout Its whole length; that it increases in bulk toward its upper end; and that the Centrifugal elements are reduced more and more. They say that the centripetal wood is intercalated between the pole and the Suter face. It is regarded as the primary wood (developed from the Precambium), while the centrifugal wood is regarded as secondary (developed from the cambium). 7 present investigation shows that this statement needs modi- ‘on. While all centripetal wood is primary, all primary wood is 374 BOTANICAL GAZETTE [NOVEMBER not centripetal, as one would interpret from the treatise cited. It has been shown that the transition from endarch to exarch is carried through in the metaxylem, both centripetal and centrifugal wood occurring long before secondary wood is developed. It is very hard to tell where protoxylem ends and metaxylem begins, and where metaxylem ends and secondary wood begins. The separation of metaxylem from secondary wood by means of the thin-walled par- enchymatous cells is not a safe guide in the region of transition, and only becomes well marked above this region, where the separation of secondary from primary wood is well marked by the thin-walled parenchymatous cells, as noted by many authors. The metaxylem above this point gets to be relatively very bulky, while the secondary wood is represented merely by a few elements. ‘These were the few pitted cells which presented to Von Mout (1) a situation without 4 counterpart, now known to be the herald of the secondary W which has gradually crept up into the petiole, a transformation begun in its early ancestry, according to Scott, the “new wood” driving out “the old,” the former being the only wood present in the higher gymnosperms and angiosperms. MATTE (6) argues in very much the same way as does METTENIUS; an argument which would hold good if the protoxylem and a large part of the metaxylem were left out of account. MATTE says that the bundles of the cotyledons have centripetal wood throughout, centrifugal wood only below the upper region of the petioles, am centripetal and centrifugal wood equally well developed at the bases of the petioles. In the present investigation it has been pointed out that there is no centripetal wood at first, and that it gradually increases; while the centrifugal wood diminishes in bulk to the upper extremiti® where it is less than the centripetal but does not disappeat entirely. Matte further says that what has been said of the cotyledonary traces applies equally well to the foliar traces, except that there * ” trace of centrifugal xylem in the youngest leaves. It can be show" tia aS soon as there are enough xylem elements to show the direction development the centrifugal wood is present, but gradually disappea® and the centripetal wood increases in the same ratio, until in the upp extremities there is only centripetal wood. This also agrees a : BERTRAND and RENAULT, except that their statement that centripe — 1908] THIESSEN—DIOON EDULE 375 tal wood is primary and centrifugal wood secondary does not hold true, a mistake apparently shared by Marre. It has been shown that protoxylem and metaxylem may have both centripetal and cen- trifugal elements. This is very well seen in cross-sections at a low level of a young strand, where only a few xylem elements are devel- oped. In such a section the protoxylem lies against the inner edge of the bundle, and the procambium can be seen to occupy considerably more than half of the bundle; the boundary of the procambium and the protophloem is distinctly recognizable, the protophloem forming only about one-third of the bundle. In the upper extremities of the petiole, also, there may be seen at an early stage a considerable amount of procambium outside the protoxylem; as these usually fail to de- velop xylem, thin-walled cells occur between the primary and second- ary wood in the upper extremities (fig. 21). The girdling habit was first noticed and described by KARsTEN (2) in Zamia muricata,®without, however, giving the definite number of traces, LEstTrBouDors (3) adds nothing new except that the traces branch and anastomose. METTENIUS (4) next misinter- preted the situation, as described in the historical introduction (P. 357). In the embryo and young seedling,”at least, the leaf traces pursue definite and well-defined courses and constitute a definite system. Four traces are invariably found to leave the vascular cylinder for fach leaf. A few anastomoses occur here and there, but these are always reducible to four strands. On two occasions only five strands "ere found in one of the cotyledons. In the older seedlings anas- tomoses are more abundant, but so far as observed these can be Teduced to the system found in the young seedling. When Karsten (2) described the girdling habit, he suggested a Cause for it in saying that the bundles are formed very early in the Young leaf, and that the originally narrow curves are later crowded far out by subsequent growth and the appearance of new organs. "TTENIUS (4) also gives a reason for girdling as follows: “In the developmental stage the traces of the youngest leaves lie in the region of the vegetative point, and at first ascend in an almost perpendicular ction, but during the further growth assume gradually an almost Zontal position, and with subsequent growth are lengthened and 376 BOTANICAL GAZETTE [NOVEMBER the expanse is increased.”” MATTE (6) assigns almost exactly the same cause. A definite cause for the girdling cannot be given at present, for it seems to be deeper seated than at first suspected. The even distri- bution of the four strands of each leaf in the vascular cylinder appears to be the dominating factor. When the primordium appears on the stem tip, its distance from the potential vascular cylinder is very short, and the same conditions that determine cell division in the develop- ment of the leaf, cause the diff tiation of cells along certain paths that run from definite points in the procambium to definite places into the developing leaf. After the traces have been started, they con- tinue to develop with the further growth of all the tissues; new organs appear and intercalary growth continues; thus the strands are lengthened more and more and their curves are widened to keep pace with the ever increasing growth of the plant. Summary 1. The vascular cylinder of the embryo is a protostele, but becomes a siphonostele in the seedling. It is very short and squarish in cross: section, one of the diagonals of the section being at right angles to the inner faces of the cotyledons, and the other parallel with them. Near each of the four corners is a group of protoxylem cells, the Jon8 diameter of whose section extends along the diagonal. 2. The four protoxylem groups extend downward to form the protoxylem of the root. ds of each coty- arallel with strands One and the other branch (from the same group). runs into of the other cotyledon (opposite the first). jindet 4. For each leaf or scale four strands leave the vascular 1908] THIESSEN—DIOON EDULE 377 at points not definitely located but well-distributed; two strands of each organ leave the cylinder approximately on the same side as the leaf for which they are destined, and run more or less directly through the cortex into the central or abaxial part of the petiole without branch- ing; while the other two strands of each organ leave the cylinder approximately on the opposite side and describe a wide curve around it, the one in one direction and the other in the other, and finally ascend in the dorsal or adaxial part of the petiole, branching repeat- edly. The girdle on the side toward which the spiral may be said to turn is generally the longer one. 5- When the cotyledonary vascular strands leave the vascular cylinder they are endarch, gradually become mesarch in their upward Course, and finally approach the exarch condition. 6. The foliar vascular strands also are endarch at their separation from the vascular cylinder, and in their upward course become Mesarch and finally exarch. In the very young leaf this transition extends through the whole base and petiole uniformly; but in the Adult leaf it is comparatively rapid through the base up to the lower Part of the petiole, where only a few centrifugal elements remain, and Which remain uniform until in the rachis, where the transition is com- Pleted, so that in the pinna only centripetal xylem is left. 7 In the lower stretches of the foliar strands a considerable amount of the centrifugal wood is primary xylem. : 8. In the foliar strands of the embryo and seedling, the xylem issue, so far as developed, from below upward passes from an inner to a central position in reference to the whole bundle. 9. The girdle is established very early, and is horizontal from the ing. Untrep Starters GEOLOGICAL SURVEY Wasuincton, D. C. : LITERATURE CITED * Von Mont, Huco, Ueber den Bau des Cycadeen-Stammes und sein Ver- hiltniss zy dem Stamme der Coniferen und Baumfarn, Abhandl. Kgl. Bay. nt Wiss. 1: 399-442. pls. 18-20. 1832. : “ TEN, G., Organographische Betrachtung der Zamia muricata Willd. Abhandl. Kgl. Akad. Wiss. Berlin 1856:193-219. pls. 1-3. 378 BOTANICAL GAZETTE [NOVEMBER 3- Lestisoupors, Ta., Mémoire sur la structure des Cycadées. Compt. Rend. 51:651-655. 1860. 4. Merrentus, G., Beitrige zur Anatomie der Cycadeen. Abhandl. Kgl. Sachs. Gesells. Wiss. 5:565-608. pls. 1-5. 1861. 5. Bertranp, C. Ec., et RENAuLT B., Remarques sur les faisceaux foliaires des Cycadées actuelles et sur la signification morphologique des tissues des faisceaux unipolaires diploxyles. Arch. Bot. Nord. France 2:232-242. 1886. (Rev. Compt. Rend. 102:1184-1187. 1886.) Matte, Henri, Recherches sur l’appareil liberoligneux des Cycadactes. Caen. 1904. a EXPLANATION OF PLATES XXIII-XXIX PLATE XXIII Fic. 1—Embryo in mature seed: cot, cotyledon; sh, tubular sheath of cotyledons; st, stem proper; r, hypocotyl; s, suspensor. ' Fic. 2.—Cross-section of embryo just above stem tip: cof, tubular part 0 colytedons; Ly, first leaf; Li, L?, L3, L4, vascular strands of first leaf; L., second leaf; L3, Li, 3, L4, vascular strands of second leaf; L;, third leaf. a 1G. 3.—Median longitudinal section of lower part of embryo, parallel wi inner faces of cotyledons: cot, cotyledon; L;, La, first and second leaves; S pinna; /s, foliar strand; st, stem tip; , pith; cs, cotyledonary strand; vp, vas cular plate; /, plerome; cp, caplike tissue; sp, suspensor. 1G. eee cemeat aco, of part of vascular system rs embryo; cof, cotyledon; #b, tubular part of cotyledons; cs, cotyledonary stran®» Li—Li, foliar strands of first leaf; Li—L4, foliar strands of second leaf; * vascular plate; a, protoxylem elements continuing downward into the hypocoty- Fic. 4a.—Cross-section of a vascular bundle in upper extremity of saute leaf; x, xylem elements; a, cells losing their contents during lignification; i Procambium; pph, protophloem; 6, line showing boundary between protoxylem and protophloem. PLATE XXIV si ol Fic. 5.—Semi-diagrammatic reconstruction of part of vascular ef yes; embryo, to show especially the girdling: Lx, L», traces of first and second ie ne vp, vascular plate; px, protoxylem groups; a, xylem elements continuing from protoxylem groups to form the protoxylem of the primary root. ocigi Fic. 6.—Diagram giving bird’s-eye view of vascular system, t0 ae and girdling of foliar strands: cot, tubular part of cotyledons; cotyl | traces, one group for each cotyledon; L,, Lz, L3, L,4, first, seco ss ee 7 ES L3, L4, traces of first leaf; Li, L3, La, 4» Second leaf; px, protoxylem groups. Fic. 7.—Outline of ieee just above stem tip of seedling three °F Page ce 3 = > . ~~ Seu aa —— = bl THIESSEN on DIOON EDULE PILATE XXIV BOTANICAL GAZETTE, XLVI THIESSEN on DIOON EDULE BOTANICAL GAZETTE, XLVI PLATE XXV oe N a Ns As B ee, ENS Za] \ 0} RS, Ae , Aaah WN), Garena i VS ya Uite ADyY a ia Wc i Ye ay dl WN) ins aigilsiiag Se set we 4 SERS. eae Satie THIESSEN on DIOON EDULE occas GAZETTE, XIVI PLA LE XXVI THIESSEN on DIOON EDULE BOTANICAL GAZETTE, XLVI | PLATE XXVII SS Nae \ ) Sy acon D aU. Naa BOTANICAL GAZETTE, XLVI LA (] ' eee, LY iTS AT == LAT R ee V4 i sof SHH NY Uy UM } () rh ty oa 25 We! es oy je ia pw A LFA Y ACY Ce ae ee wi THIESSEN on DIOON EDULE 7 ae Y @' PLATE XXVIII BOTANICAL GAZETTE, EVE THIESSEN on DIOON EDULE PLATE XXIX BRIEFER ARTICLES NEW COLORADO SPECIES OF CRATAEGUS (WITH TWO FIGURES) During the past three years the writer, together with Messrs. G. S. Dopps and W. W. Rossrns, has been making ecological studies of mesa and gulch plants in the vicinity of Boulder, Colorado. In tracing out the distribution of Crataegus it became apparent that there were present some undescribed species. Full and complete collections were made therefore by Mr. Dopps and the writer during the present season from marked trees, in order that there could be no confusion in regard to the Specimens. Very complete notes of abundance, occurrence in different drainage areas, etc., were made. Fruits were preserved in alcohol as well as by drying. It was expected at the beginning of the study that the new forms would be found to be hybrids between previously described species. This, however, is not the case. The distribution of C. Doddsii, in particular, shows that it is a true species. Isolated thickets of C. Doddsit have been found as far as five or ten miles away from any trees of other species of Crataegus. Various other considerations which will be noted elsewhere lead to the belief that the Colorado species of Crataegus do not hybridize. A paper by my colleague, Professor T. D. A. COCKERELL," gives a full account of the species described for Colorado up to the present time. Tam much indebted to this paper and to suggestions from its author. The following species have the characters of TOMENTOSAE of SARGENT and should be placed in that group. The first might almost as well be Placed with CoccrnEae. e Crataegus Doddsii, sp. nov.—Arbor parva, vel frutex; ramis cineraciis, spinescentibus; ramulis junioribus glabris vel paululum pubescentibus, colore castaneato. Folia lucida; glabrata, sed nerviis infra pubescentibus ; obovata, saepe ad apicem truncata, margine serrata, et superne obscure lobata. Petiolus longe }-4 laminae; superne margine angusta glandulosa. Flores conspicui; corymbis compositis ; pedicellis glabris vel majus minusve pubescentibus; staminibus ro vel minus; antheris albis. Fructus durus, cum pilis raris, late pyriformis; longe 9™™, in longitudinem costatus; - * Univ. of Colorado Studies 5241-45. Dec. 1907- 381] [Botanical Gazette, vol. 46 382 BOTANICAL GAZETTE [NOVEMBER colore ruber sanguineusve; autumno maturans; nucellis osseis, 2-3.— Fig. r. Hab. in Colorado, U. S. A. Fic. 1.—Crataegus Doddsii, natural size. This species is nearest related to C. erythropoda, from which it ne ee the anthers white (not pink), in having less shiny leaves, in the pres? 1908] BRIEFER ARTICLES 383 pronounced ridges in the fruit, and in the lighter color of the fruit (that of C. erythropoda is mahogany brown). Type specimen: Ramaley and Dodds 6181, Pole Canyon near Boulder, Colorado, Sept. 19, 1908. Type in University of Colorado Herbarium; cotype Fic. 2—Crataegus coloradoides, natural size. in ccs Rocky Mountain Herbarium, Laramie, Wyoming. Material is at hand from “atlous localities in Boulder County, s000-Sooott altitude. ee coloradoides, sp. nov.—Arbor parva, vel frutex: ramulis < Us pubescentibus; ramis spinescentibus. Folia supra cyaneo- da, lucidula, infra glauca; obovata; margine serrata et parve lobata; 384 BOTANICAL GAZETTE [NOVEMBER nerviis infra pubescentibus. Petiolus pubescens, longe $4 laminae. Flores conspicui; corymbis compositis; pedicellis pubescentibus; stami- nibus 10 vel minus; antheris albis. Fructus autumno maturans; mollis, dulcis, ruber vel puniceus, globosus (9™™), levis non costatus, cum pilis raris; nucellis osseis, 2-3.—Fig. 2. Hab. in Colorado, U. S. A. This species is nearest to C. occidentalis Britt., but has much longer petioles, smaller, shiny leaves, not dull, somewhat smaller fruit, which is globose, not broader than long as in C. occidentalis. The tree is also less gnarled and there are no persistent bud-scales at flowering time. . ype specimen: Ramaley and Dodds 6184, Pole Canyon near Boulder, Colo- rado, Sept. 19, 1908. Type in University of Colorado Herbarium; cotype in Rocky Mountain Herbarium at Laramie, Wyoming. ; The species grows in gulches in the lower foothills from 5500 to 7000 altitude; mostly about 6oooft, It may be of interest to students of Crataegus to point out that the fluting of the fruits, as in C. Doddsii, is a character which has apparently not been used by other observers. In alcoholic material and in well-dried specimens this character is very noticeable. Attention is called to the cross- section of the fruit shown in the drawing (jig. 1),—FRaNcis RAMALEY, University of Colorado, Boulder, Colorado. SEXUAL CONDITION IN FEGATELLA Until the last few years, nothing has been known in regard to the sik ual differentiation in the sporophytic stage of dioecious bryophytes. * connection with a discussion of the germination of the zygotes of sre dioecious molds, the writer? first pointed out this lack of knowledge me [ subject and raised the question whether a capsule of a dioecious oe contains both male and female spores or spores of but a single sex. prey question so far has been settled by the writer? for the single hepatic bula chantia polymorpha, and by the Marcuats3 for the three mosses these unguiculata, Bryum argenteum, and Ceratodon purpureus. In 2 jum forms, as well as in the germinating mold Phycomyces, a single oe dal was found to contain both male and female spores as judged by a they produced when sown in pure cultures. 1 hepatic he purpose of the present brief notice is to add the dioecious hep * Zygospore germinations in the Mucorineae. Annales Mycologicl 4775: oe ? Differentiation of sex in thallus, gametophyte, and sporophyte. egies 422161-178. 1906, i __ 3 Recherches exp€rimentales sur la sexualité des spores chez les Mousses eee Mém. couronnés C], Se. Ac. Roy. Belgique 2':1-50. 1906. 1908] BRIEFER ARTICLES 385 Fegatella conica to the list of bryophytes already investigated, and to give increased weight to the opinion that the type of sexual differentiation in the forms so far studied is at least the predominant if not the universal type among the bryophytes. April 22, 1906, Fegatella was found by the writer abundantly fruiting in the large pot holes in the Gletschergarten at Lucerne. The capsules for the most part were not yet opened. Two days later, in the Botanical Laboratory at Halle, unopened sporangia were carefully dissected out, and after a microscopic examination to make certain that no spores from other sporangia had adhered to their outer surfaces, they were preserved sepa- tately in small sterile paper envelopes. Spores from one of these single sporangia were sown May ro in several Petri dishes in 0.1 per cent. Knop’s solution. By June 19, the germinations from the spores had grown to Sufficient size to be readily handled, and accordingly 128 from a single Petri-dish culture were transplanted to earth in regular rows in large shallow pots. They had reached a considerable size but were not sufficiently Matured to produce their sexual organs when it became necessary in the latter part of July to leave them in the care of the Diener of the laboratory. The coming November a number of the plants were shipped to the writer packed in parchment paper with damp sphagnum moss. Fegatella does hot multiply non-sexually by gemmae as does Marchantia, and there is Practically no danger of infection in the earth cultures from thalli of the Same species. Of the plants shipped, twelve survived the two weeks’ journey and Were sown in separate pots in the Harvard Botanic Gardens, where they have since been kept growing. Three of the cultures by the character of the sexual organs produced have shown themselves to be female and fight to be male. A single capsule of Fegatella, therefore, contains both male and female unisexual spores. The other cells of the sporophyte, undoubtedly, are hermaphroditic in character, although attempts to demon- Strate this by regenerations from the stalk or wall of the sporangia were fntire failures. One of the twelve pots, presumably with only the growth from a Single spore, showed both antheridia and archegonia, but it was not Possible to find that the lobes producing these different sexual organs Were connected. It is possible that the differentiation of sex is not always complete in the capsule of Fegatella, and that hermaphroditic Spores are in fact occasionally produced, as is the case in the mold Phycomyces; but it seems more likely that a fragment of a thallus of the T sex became accidentally mixed with the growth planted in this Particular pot.—A. F, BLAKESLEE, Connecticut Agricultural College, 386 BOTANICAL GAZETTE [NOVEMBER _ A NEW CHARACTERISTIC OF ENGELMANN SPRUCE In 1907 near Bernice, Mont., the writer observed a specimen of Engel- mann spruce (Picea Engelmanni Engelm.) with resin vesicles in the bark, which are so typical of the genus Abies. They are not mentioned in any of the descriptions of Engelmann spruce, and the character appears to have been entirely overlooked by botanists. It is therefore desired to direct attention to this noteworthy feature and place it on record. Since 1907 it has been observed at several places in Colorado, and is probably found every- where on this species of spruce. The vesicles or “blisters” are not so abundant or conspicuous as in the genus Abies. In a few instances they were found to be well developed and closely resembled the balsam blisters. Commonly, even when of large size, they were rendered obscure by being deeper in the bark. The only genus besides Abies previously described as having these vesicles is Pseudotsuga, in which they are less conspicuous than in Abies. To these two genera must now be added at least one species of the genus Picea, which shows this common character in many individuals, though it is rarely prominent.—E. R. Hopson, Washington, D. C. CURRENT LIPERAIT Ure BOOK REVIEWS The Wiesner Festschrift As a testimonial of esteem and affection, the friends and pupils of Jurrus Wiesyer, the distinguished director of the plant-physiological institute of the University of Vienna, prepared for his seventieth birthday (January 20, 1908) a volume’ containing more than forty papers, which are of course predominantly Physiological. Only one is from this country: TRELEASE gives an account of variegation in the Agaveae, with many illustrations. It is only possible to give an idea of the scientific contents by stating most briefly the drift of each paper. TscHircH opens the volume with a brief sketch of some ideas on the rela- tionships and origins of the resins and gums, as to whose chemistry light is break- ing. Moxiscu shows that Xylaria Hypoxylon, X. Cookei, Trametes Pini, Polyporus sulfureus, and Collybia cirrhata are to be stricken from the list of uminous fungi. STRASBURGER discusses nuclear division in the Characeae, with special reference to the so-called amitosis, which he holds is not a senile process. Vow Hounet and LrrscHaver present a synopsis of Austrian Corticeae, includ- ing 131 species, of which 5 are new. Mostus figures and describes the siliceous accretions in the stem and leaf cells of the tropical American Callisia repens (Commelinaceae). Czapex discusses the relation of geotropism to certain fea- tures of plant form, especially to the position of branches both of stems and Toots. BURGERSTEIN gives a synoptical key to the genera of Coniferae, based on the anatomical characters of the wood. Von PorTHErm and Samec report less dissimilation (“respiration”) in seedlings of pea grown in Ca-free solutions than in Ose grown in Knop’s solution. Darwin shows by various methods that the Petceptive region for gravity and light is in the cotyledon of Sorghum, thus dis- Posing of objections that have been raised to this view. ae AUSEK gives a further account of the “‘carbon-layer” of the pericarp of certain Compositae. Gore finds the relations of symmetry in a considerable umber of flowers and inflorescences examined to be explicable neither by pres- Sure nor purpose, but rather by ‘“‘nutritive relations” (not more exactly analyzed). Ricurer declares (on results derived from the usual but inconclusive culture Methods) that calcium is a necessary food element for a colorless diatom, prob- ably Nitschia putrida. SeNFT demonstrates the occurrence of physcion and Parietin in lichens, and the methods of recognizing them microchemically. “BONS caer pegs een * WiEsNER-Festscurirt. Ed. by K. LiNsBAUER. 5vo. pp- vili+ 548. pls. 23. Ags. 56. Wien: Verlagsbuchhandlung Carl Konegen. 1908. Ar. 24 geb. 28.80. 387 388 BOTANICAL GAZETTE [NOVEMBER AMBRONN indicates the chemical and physical alterations which the cellulose of textile fibers undergoes when impregnated with zinc sulfid. NEsTLER has extended MacDoveat’s studies on the skin poison of Cypripedium spectabile secreted by the glandular hairs. N&EmEc writes briefly on his experiments upon regeneration with the roots of Taraxacum. SrToxk asa declares unequivocally that in anaerobic and in aerobic respiration the formation of lactic acid, alcohol, and CO, (and in addition acetic and formic acids in aerobic respiration) is due solely to enzymes. KAMMERER describes a case of symbiosis between Ocedogonium undulatum and aquatic larvae of Aeschna cyanea. GRAF furnishes an appro- priate study of the gum-ferment whose action WIESNER first correctly described. HEINRICHER adds to his two previous papers on the effect of light upo? germination of seeds a general discussion of the subject, with some new expéet- ments and a valuable summary. Mrxkoscu finds that the scion of Epiphyllum grafted upon Peireskia as a stock, exercises a definite effect in giving rise in its cells to the bodies peculiar to Epiphyllum. F1cpor reports exact determinations of the phototropic sensitiveness of certain plants in relation to the zone of indiffer- ence (which seems not to exist in some). KoorpErs again describes and figures his Javanese genus Wiesneromyces. Zikes has a further account of his Ba¢- terium polychromicum and its pigment production. VoN WETTSTEIN observed a saltatory rise of the fertility (at first small or none) of the pollen in two undoubted bastards of Sempervivum, and suggests that here may be an important factor the origin of new forms. Von WeINzIRt contributes data on the mechanica functions of the various organs of the embryo of cereals in their escape from investing structures. K. LINSBAUER reports propagation of the excitation 0 the primary petiole of Mimosa at a rate of roo™m-sec, and a reaction time averagi” 8 0.09 to 0.355, with minimum 0.07 and maximum 0. 80°. Cay Fritscu describes cystoliths of Klugia zeylanica. RACIBORSKI recognizes ” Coreopsis tinctoria prolifica “‘an undoubted mutation.’ L. LiNsBAUER gives an account of “photochemical induction” in the formation of anthocyan in the etiolated seedlings of buckwheat. KRasser makes a critical synopsis of the lower Lias flora of the Austrian Alps. ScHIFFNER presents an ecological study of so-called Knieholzwiesen of the Iser Mountains. WEGSCHNEIDER states os the fats are really saponified by stages and the reaction is only apparently ase lecular. Skraup writes briefly on the leucin of proteins. STROHMER gre” account of the accumulation and migration of saccharose in the sugat cei KarzEL shows some interesting peculiarities in the lignification and cutinization of the walls of the stomata in cycads. Przrpram notes the renewed growth ~~ atumps of red wood, familiar to Californians. W1LHELM figures a remar kable distortion of the tips of a fir. Loprrore writes on twin-roots in Zea and kee? Besides the papers listed, there are several on more general topics, histor or philosophical, that are omitted for lack of space. The volume is 4 oc and gives evidence of the inspirational force of a great investigator 1908] CURRENT LITERATURE 389 MINOR NOTICES Botany and Pharmacognosy.—A third edition of KRAEMER’s Textbook? has appeared with great promptness after the publication of the second.s The changes made have to do chiefly with the illustrations, fifty unsatisfactory half- tones being replaced by line drawings, and several new illustrations being intro- duced, especially of solanaceous drugs and plants.—J. M. C. NOTES FOR STUDENTS Chlorophyll and assimilation.—LupimENKO, who has been devoting his attention to the influence of light upon various processes, has endeavored to solve these questions: Is the intensity most favorable for the decomposition of HCO, likewise the most favorable for the production of dry matter? What is the optimum illumination which will produce the most dry matter in different gteen plants? How is this optimum related to the various quantity of chlorophyll quantitative variations in chlorophyll due to illumination and temperature are Smaller than in the latter, which also for the production of a maximum quantity Tequire a more feeble light than the former. In general the maximum of Pig ment corresponds to a light sensibly weaker than that required for a maximal Production of dry matter. From which it would appear that light, as inferred for other reasons, has a special action in the formation of chlorophyll. : The production of dry matter increases with the light absorbed, up to a maxi- Mum, then diminishes. This optimal light is constant with the same species at ‘onstant temperature, but diminishes as the latter increases. [This indicates that the energy optimum is a constant.] The optimal intensity for the produc- “on of dry matter varies according to the quantity of chlorophyll, in petaaserns as the pigment diminishes, and vice versa. In nature the maximal production Plants poor in chlorophyll corresponds to the normal daylight, but in those Ear err * KRarMER, Henry, A textbook of botany and pharmacognosy. Third edition. Pp. Vili+ 850, figs. 328. Philadelphia and London: J. B. Lippincott Co, 1908. $ Reviewed in Bor. Gazette 46:231. 1908. : j *LusmwenKo, W., Production de la substance séche et de la chlorophylle is végétaux supérieures aux différents intensités lumineuses. Ann. Sci. N . 73321415. 1908, 390 BOTANICAL GAZETTE [NOVEMBER rich in pigment it corresponds to a greatly weakened light. In general the development of the plant is proportional to the dry matter produced; but growth is not exactly proportional thereto, for it is more feeble in strong light and more vigorous in weak light than it would seem if it were measured by the augmentation of the dry weight. The root and stem are unequally affected; the former grows more and the latter less as the illumination increases; but too strong a light reduces the rate of growth of both because less food is produced. The develop- ment of the leaf blades generally increases to a maximum with decreasing light, but diminishes with further enfeeblement. With some exceptions transpiration does not have any sensible effect on the total production of dry matter, though the quantity in proportion to the fresh weight generally diminishes with the diminished light. All the green plants are capable of regulating the quantity of light absorbed, and so partly avoiding the injurious effect on production of dry matter, by altering the quantity of chlorophyll produced. These adaptations are limited in plants poor in chlorophyll; but those rich in pigment can adjust themselves to a rela- tively very weak illumination. Biologically the massing of plants ought to be an advantage by reducing the illumination. Physiologically the action of light is not limited to the reduction of H,CO,, for it affects also the speed of incor- poration [assimilation] of carbohydrates. The former demands a stronger light than the latter, for which there is an optimum, and below and above this it rapidly diminishes in rate. It is by this retarding action of bright light upon the incor- poration of carbohydrates and a consequent considerable accumulation of foods in the green tissues that the diminution in the production of dry matter is expli- cable when the illumination passes a certain limit. [This explanation does not explain and surely needs further consideration.] If the chemical transformations which constitute the incorporation of carbohydrates are of enzymic nature, it IS probable that they are affected by the action of light on the formation and destruc tion of enzymes. [Is not the fate of the greater part of the carbohydrates ' be sought rather in protein synthesis than in “incorporation; ” and is there any evidence of enzymic action in this process ?]—C. R. B. Self-digestion and endospermic respiration.—The long effort to settle the question of the vitality of the endosperm, which was begun by Gris and VAN GHEM, Was practically abandoned after the culminating researches of BROWN and ESCoMBE, PuRIEwitscH, and Brown and Morris. Since that time very little indeed has been contributed to the subject. Perhaps one reason was oe the results of somewhat related investigations so modified our knowledge of enzymes and respiration that self-digestion as a test of vitality was no longer Pegi as valid. Altogether disregarding such opinions, BRUSCHI® takes Se Problem practically as it was first attractive fifty years ago, “to solve sherds Dana, Researches on the vitality and self-digestion of the eae sperm of some Graminaceae. Annals of Botany 22:449-463. 1908. 1908] CURRENT LITERATURE 301 question whether the reserve material contained in the endosperm of amyliferous seeds is exclusively digested by enzymes secreted during germination, or whether the endosperm cells renew their vital activity and themselves dissolve their own food material.”’ The endosperms of maize, wheat, rye, and barley were tested. The seeds were allowed to soak 48 hours before removal of the embryo and scutellum in some instances, and in the other tests no statement is made on this point. No controls are mentioned; in fact the experimental data are so meager that the reader is compelled to reject the results simply because the author leaves him too ignorant to judge. In the digestion tests no controls are mentioned. The simple statement that aseptic conditions were maintained is altogether insuffi- cient. We read that chloroform water was used, but whether it was saturated or half saturated or something else the reader cannot know. ‘The general trend of the conclusions is that all of the endosperms mentioned are more or less capable of self-digestion, and that such activity is independent of vitality. The endo- Sperm of rye is pronounced dead, but in maize, barley, and wheat there is more or less vitality in some of the amyliferous cells. Stowarp® has found that the pure endosperms of Hordeum and Zea under appropriat diti ifest a gaseous exchange of respiratory character. He also regards similar behavior on the part of the aleurone layer as strengthening the evidence that the cells of that tissue possess vitality. The paper is presum- ably an initial effort, because (a) the introduction as such is unnecessarily tedious, and as a digest of the literature is deficient in so far as a judicial analysis is con- * cerned, and is not as comprehensive as others already published; (0) after about ten pages of tabulated data a new subject is at once begun with no discussion or con- sideration of the significance of the experimental results recorded. This pot-pourrt style of composition is more or less reflected in the impression one receives of the author’s tendency to think of several matters without analysis and correla- tion. On the other hand, all the experimental procedure is very carefully described and the reader can analyze the results. In spite of the fact that the Tespiration tubes were “tarred” instead of tared, one is inclined to accept the Tesults as reliable and the conclusions as sound.—Raymonp H. Ponp. Plant diseases.—The last annual report (21st) of the Agricultural Experiment Station of the University of Nebraska, issued January 29, 1908, contains the following papers of interest in reference to plant diseases. : Poor? discusses several diseases of tomatoes. Black rot, due to Alfernaria Sasciculata (C. & E.) Jones & Grout, occurs on the ripe fruit at the blossom end. cavities within the diseased tissue are lined with the fluffy mycelium of the Sus. It was isolated and inoculations were made upon both ripe and green eaicgergne ee °STowarp, FREDERICK, On endospermic respiration in certain seeds. Annals of Botany 22:415-448, 1908. 7 Poot, V. W., Some tomato fruit rots during 1907. 392 BOTANICAL GAZETTE [NOVEMBER fruit. Five days after inoculation the rotted area of the ripe fruit was 1.2°™ in diameter. No infection occurred in the green fruit. Culture characteristics are discussed. Rhizoctonia on the tomato is also discussed, the disease being marked by a chocolate-colored, wrinkled epidermis. The fungus penetrates the cells in all directions, and no conidia are formed. It was isolated and tomatoes were inoculated, resulting in their complete decay in two weeks, both ripe and green fruit. The ripe rot due to Colletotrichum lycopersici was studied. The fungus was isolated and inoculations were made, producing four days after infection a diseased area 0.6°™ in diameter on either ripe or green fruit. Fusarium of undetermined species and also F. Solani Mart. were isolated, used in inocula- tions, and the culture characters determined. Miss WALKER’ discusses and describes a form of Sphaeropsis differing from the ordinary form principally in the size of the spore, the size and thickness of pycnidium, and the absence of the ostiole. The new form seems to be more vigorous as a rot-producer that the old one. Inoculated into apples in every case it produced the characteristic black rot. The author suggests that possibly the variation in size of the spore may be due to the nature of the fruit upon which it is growing. HeaAtp® briefly describes the various types of barley smuts, with notes hoon experiments as to the best mode of treatment for their prevention. The following treatments were used: formalin steep, modified formalin steep, hot water treat- ment, corrosive sublimate steep, copper sulfate steep. The percentage of ger- mination was lessened by all the treatments except the hot water, being reduced 40 per cent. by formalin 1/10, and 70 per cent. by 1/15. The author recommends as the formalin steep one pint to 20-25 gallons of water. : Wotr?? found Pestalozzia uvicola on ripe grapes. It was isolated in pure culture and inoculations made upon the grape, resulting in numerous pustules after proper incubation period. Sections of these pustules showed the characteristic spore, but, contrary to the usual mode of Pestalozzia, the spores were borne what the author regards as well-defined pycnidia, which structure would be entirely out of accord with the genus or with any of the Melanconiaceae. It is unfortunate that the drawing (p. 71) leads one to infer that the spores are not borne in the true "pycnidium, as the author describes, but rather in the cavity resulting from hypertrophy of the surrounding host tissues.—F. L. TEVENS. F Mold of maple syrup.—This mold, frequently observed during the past years, has been ascertained by Heatp and Poot"! to be Torula saccharina - was grown in pure culture on media of varying composition. They conclu 4 that the concentration of the sugar solution in which the fungus was 8f° ® Warxer, Leva Bett, A new form of Sphaeropsis on apples. ® HEAatp, F. D., Seed treatment for the smuts of winter barley. "© Wotr, F. A., A rot of grapes due to Pestalozzia uvicola Spegaz- ** Heatp, F. D., AND Poot, V. W., The mold of maple syrup. 21st Ann. Rep- Univ. Neb. Agric, Exp. Sta. 54. 1908 1908] CURRENT LITERATURE 393 had little effect on the size of the spores or hyphae; and that ammonium nitrate can be used to a limited extent as a source of nitrogen, but that it is rather poorer than ammonium tartrate-—F. L. STEVENS. The vegetative activity of chromatin.—DERSCHAU’S” results and theoretical views on the vegetative activity of chromatin are interesting. Many granular chromatin substances thrown out of the nucleus into the cytoplasm increase in size, assume spherical forms, and then, becoming oriented at the poles of spindle figure, function as centrosomes. This is regarded as the vegetative activity of the chromatin. His studies cover several forms of higher vascular plants, such as Fritillaria imperialis, Iris germanica, Vicia Faba, Lilium Martagon, Funkia steboldiana, and Osmunda regalis. From his investigation of the pollen mother cell and meristematic tissue of these forms, he concludes that there exist central ies in the mitotic figure of the fern and flowering plants which are of nuclear origin and are analogous to blepharophlasts. The following is a brief summary of his account. In very young mother cells of Lilium, Funkia, and Osmunda, chromatin is observed escaping from the nucleus in various spots. Outside the nucleus the chromatin substances increase in size and assume spherical forms. The spherical chromatin substances refract light and close examination of them seems to show a reticulated structure. With Stains they react like chromatin and linin. While the chromatin is escaping the nucleolus remains within, which shows that the substances thrown out are not nucleolar. In late prophase the spherical chromatin or ‘“‘Sphaere” seems loosened and differentiated into two structures, one the center and the other a single heavy ed fiber. Some of these centers make their way toward the Hautschicht during a later phase of mitosis and furnish the anchoring-place for the spindle; Some lie scattered in the cytoplasm; and still others remain near the nuclear per- phery. To each of these centers there is attached a single heavy beaded fiber, ftom which there seem to be spun out fine spindle fibers. Generally the spindle Start as multipolar polyarch, then become bipolar, but remain in the Polyarch condition until telophase; and therefore several centers persist without ion at each pole, each spindle cone being associated with a single center. In tafe Cases some of these centers fuse together to form a kinoplasmic plate, which S connected by beaded heavy fibers with other centers that remain separate. In telophase the central and mantle spindles again take on a beaded structure. The centers and fibers, instead of entering into the constitution of the organizing daughter nucleus, remain in the cytoplasm and undergo certain changes in the Stfucture. These centers at the pole of the spindle, DERSCHAU thinks, control - Mechanism of mitosis. He states further that the centers may be asdietsvagon allied to the blepharophlast, and are to be regarded as analogous with it, if not homologous; both lie near the nucleus, increase in volume, and mark the starting- Point of fibers—one of cilia and the other of spindle fibers SHIGEO YAMANOUCHI. he. ie Blepharophlasten. HAU, M. v., Beitrige zur pflanzlichen Mitose, Centren, Blep Jahrb, Wiss. Bot. 46: 103-118. pl. 6. 1908. 394 BOTANICAL GAZETTE [NOVEMBER Cytology of Ascomycetes.—Miss FRASER and Miss WELSFORD have recently added another contribution's to their important series on the cytology of the Ascomycetes. The present investigation deals with two additional Discomy- cetes—Otidea aurantia and Peziza vesiculosa, The authors have studied princi- pally the triple reducing divisions in the ascus, and their observations accord in the main with those of HARPER on Phyllactinia. They find in these two species, however, intermediate conditions between the early pairing of the chromosomes in Phyllactinia and their complete independence during the stages preceding reduction in Humaria, as described in an earlier paper by Dr. FRASER. Otidea, for example, the chromosomes do not pair till the prophases of the third (or brachymeiotic) division; whereas in Peziza vesiculosa they unite during the prophases of the second division in the ascus. This variation in the time of chromosome union, as described for these species, is compared in tabular form with the conditions which obtain in Humaria, Galactinia, and Phyllactinia. ae The authors describe two phases of the reduction processes—the meiotic phase, embracing the first and second divisions in the ascus, distinguished in Otidea by four chromosomes and in Peziza vesiculosa by eight chromosomes; and brachymeiosis, involving the second reduction, when the two sets of post-melotic chromosomes become separated during the third division, thus resulting in tue chromosomes in Otidea, and four in Peziza. A definite synaptic contraction occurs in connection with meiosis, similar to that first described by HARPF® m Phyllactinia; but, unlike the case in Phyllactinia and in Humaria, a second con- traction takes place in the two forms studied at the beginning of brachymetosis- The authors regard the presence of both meiosis and brachymeiosis as evidence of the occurrence of two fusions in the life-history of these forms; although 10 — — cell, and the other with the somatic division as it occu’ archesporial cells and in the ovary wall. : The results may;be summarized as follows: (1) The nuclear ret! ns to the cytology culum in of re canoes H.C. I. AND WELsForD, E. J., Further contributio e Ascomycetes. Annals of Botany 22:465-477. pls. 26, 27- 190°: ae *4SYKEs, M. G., Nuclear division in Funkia. Archiv fir Zellforschung 1:3 398. pls. 8, 9. fig. 1. 1908 25-527" pl. 16. 1908. NoteJon the,number of the somatic chromosomes. Idem ¥+5 1908] CURRENT LITERATURE 395 the resting stages of the mother cell is composed of a number-of knots connected by filaments. The pairing of the reticulum appears at a very early stage. The number of pairs of knots, though it is impossible to make an accurate count, far exceeds the number of pairs of chromosomes. She concludes that in Funkia it is inadvisable to call the knots prochromosomes. (2) Occasional contact between the pairs of knots is observed in synapsis, but they do not constitute clear cases of fusion. (3) The double thread is formed from the reticulum during synapsis , due to the paired arrangement of the constituents of the nucleus. (4) The double thread fuses into a single spirem, but at the time of segmentation into chromo- somes it splits along the line of fusion (thus an element of each bivalent chromo- some is not one-half resulting from the division of a single spirem, but an entire Piece of the double thread which fused to form a single spirem). (5) Heterotypic division of chromosomes takes place along this fission, so that there is a true reduction division. (6) In each of the daughter chromosomes a new second split occurs longitudinally. (7) The reticulum and knots in the nucleus of the pollen grain are unpaired throughout, but a double structure is found in the prophase of the somatic nucleus. (8) The number of chromosomes in the somatic nucleus of Funkia ovata and F. sieboldiana seems to vary from 36 to 48, probably is 48, the reduced number being near 24.—S. YAMANOUCHI. __ Fossil Osmundaceae.—KipsTon and GwyNNE-VAUGHAN have recently pub- lished a second contributions on the extinct Osmundaceae, which deals anatomi- cally with two species of a new genus (Zalesskya) from the Permian of the Ural. Z. gracilis and Z. diploxylon are characterized by a central cylinder, which the authors infer to be protostelic from the manner of exit of the leaf traces. Unfor- tunately in one species the center of the fibrovascular tissues of the stem has dis- ‘appeared through maceration, correlated with fossilization, and in the other by the crumbling away of the stony matrix. The authors admit that the general anatomy of the fossils is not distinctively osmundaceous. They place great ostic importance in this connection, however, on the minute structure of the xylem tracheids, which are characterized by multiseriate pits and vessel-like Perforations of the pit membranes of the terminal walls. The authors seem to attach a somewhat exaggerated importance to these features, however, since both save long been known to occur in ferns not related to the Osmundaceae. They infer that their fossils make it “clear that the central ground tassue of the recent Osmundaceae must be regarded as phylogenetically derived by modification from the central xylem of a solid (sic) protostele and that primitively it had no sooo =~ the cortex. whatever.’ This statement appears to have scarcely a better in logic or fact than their contention in the first article that foliar gaps sea Primitively absent in the Osmundaceae. Even if it be admitted that the Authors’ Species are osmundaceous, which is very far from being rotten Siclusion reached appears hardly in accordance with sound reasoning. 's Kipston, R., AND GWyNNE-VauGHAN, D. T., On the fossil Osmundaceae. I, Trans, Roy. Soc, Edinburgh 462: 213-232: pls. 1-4. 1908. 396 BOTANICAL GAZETTE [NOVEMBER fact that a protostelic genus Lygodium occurs among the living Schizaeaceae, throws no light on the morphological nature of the pith in the central cylinder of the other schizaeaceous genera Schizaea, Aneimia, and Mohria.—E. C. JEFFREY. Mitosis in Cynomorium.—Baccarini"® has published an account of vegeta- tive mitosis in Cynomorium coccineum (Balanophoraceae). From a study of the nucleus in meristem of the roots and in parenchyma of the stem, he finds the following stages: (1) Prophase: (a) chromatin granules are uniformly distributed throughout the fundamental mass of the nucleus, with or without still larger chromatin knots or joints, the chromocenters; (6) the chromatic granules, separat- ing from the faintly staining fundamental mass of the nucleus, aggregate gradually into a distinct number of larger masses, the chromocenters; (c) these chromo- centers unite to form larger masses, more compact and lengthened, which con- stitute the prochromosomes; (d) some prochromosomes fuse together by thet ends into a chain, which finally results in filaments of the spirem; the oak by this time is homogeneous in structure, but it is uncertain whether it is a single continuous thread; (e) the filaments of the spirem segment into a definite num ber of chromosomes, which seem to be more numerous than the prochromo- somes. (2) Metaphase: The chromosomes become arranged in the equatorial plate, where they divide and the daughter chromosomes separate. (3) Ana- se: The chromosomes accumulate in a convergent bundle at the pole. (4) Telophase: The chromosomes dissolve and form the fundamental nuclear mass with its chromatin granules.—Suicfo YAMANOUCHI. Riella.—In the twelfth of the Archegoniatienstudien, which he announces ' be the last, so far at least as concerns the liverworts, GOEBEL describes the Dr buds of Riella helicophylla, R. cossoniana, and R. Battandieri.17 These organs were first found by Unperwoop and Howe in R. americana, and have not a been observed in R. Clausonis. They consist of an unequally two-lobed dis attached by a single stalk cell somewhat excentrically placed on the upper eck face. GoErBEL holds these gemmae to be “‘ modified slime papillae,” as = chantia, an effort at homologizing which seems to us strained. The smaller lo 1s loaded with food and therefore heavier; so the gemma sinks in the water with this end down and from it rhizoids arise. The larger lobe, which he calls sehen disk, grows, and especially the meristematic tissue between the 1 parting them by a rather long stalk. From the germ disk two plants af at duced directly when well nourished, and otherwise one indirectly, that 35, : , fter proliferation of the germ disk. GorBet also discusses the systematic PO : F d tion of the genus, concluding on rather doubtful grounds, it seems, that it shoul : ovo ? *© Baccarint, P., Sulle cinesi vegétative del Cynomorium coccineum TE Giorn. Bot. Ital. 15: 189-203. pl. 7. £268; ad : u *7 Gorsrt, K., Archegoniatenstudien. XII. Ueber die Brutknospenbilduné Uber die systematische Stellung von Riella. Flora 98;308-323- figs: 17: age? 1908] CURRENT LITERATURE 397 form a fourth family of the order Marchantiales: Ricciaceae, Corsiniaceae, Riellaceae, Marchantiaceae, rather than be placed as an aberrant family in the Jungermanniales anacrogynae.—C. R. B Cleistogamy.—The examination of a large number of cleistogamous flowers of monocotyls and dicotyls showed HELENE RitzERow* that all are reductions from the chasmogamous forms, and that the reductions follow a definite direction determined by the normal development of the chasmogamous form. The mode of reduction in the various floral parts is described in detail. The pollen grains of many forms germinate within the anther, the pollen tubes emerging in various ways. Chasmogamous flowers are generally so situated upon the plant that they receive better nourishment than the cleistomagous. So many forms are described that the work will be good for reference. . Tuzson® has observed for six years two trees of Robinia Pseudo-Acacia, 3° to 40 years old, and has found them producing only cleistogamous flowers. Adventitious shoots, six years old, from these trees also produce only cleistogamous flowers. The author believes that in this case the cleistogamy is entirely inde- pendent of external conditions and due rather to inner causes—CHARLES J. HAMBERLAIN, Fossil polar plants.—NarHorst,”° in connection with the publication of the Tesults of the Russian Polar Expedition of 1900-1903, has given an account of the nassic and Jurassic plants from the Island of Kotelny. Schizoneura is the only Triassic plant. Among the most interesting Jurassic remains are the leaves and = scales of a pinelike conifer. As the affinity of these is not absolutely cer- tain in the absence of structural evidence, they are denominated Pityophyllum = Pityolepis respectively. The scales present a remarkable appearance, for ening from the base they narrow abruptly to an isthmus about the middle, 0 expand again at their upper ends. The question naturally suggests itself, Whether the upper region does not correspond to the apophysis of modern pines. teviewer has found somewhat similar cone scales in the Lower Cretaceous. The author takes occasion to criticize the erroneous reference of probable pine needles to the problematical Jurassic genus Cyclopitys (Sciadopitys). The latter does hot consider to form properly an element of the flora of the Mesozoic as *ccurs in the northern hemisphere.—E. C. JEFFREY. Phylogeny of Archegoniatae and Characeae.—SCHENCK** regards the bryo- = Pleridophytes, and Characeae as unrelated groups, the first two having oo Ritzerow, HELENE, Ueber Bau und Befruchtung kleistogamer Blithen. Se 163-212, figs. 36. 1907. : oo a) UZSON, JOHANN, Ueber einen neuen Fall der Kleistogamie. Bot. Jahrb. tik, Pflanzengeschichte, und Pflanzengeographie 40:1-14. pls. I, 2. 1997- 1907. pe noner, A. G., Mém. Acad. Imp. Sci. St. Petersbourg VIII. 21: no it . 23, . ar ScHENck, HEIRIcH, Ueber die Phylogenie der Archegoniaten und Characeen. Engler’s Bot. Jarhb, 42:1-37. 1908. 398 BOTANICAL GAZETTE [NOVEMBER come from the brown algae, and even the Characeae showing more resemblance to the brown algae than to other green algae. The origin of antheridia and archegonia from a plurilocular sporangium is developed along the lines already presented by Davis and Hotrerty. To some of us, it would seem better to derive antheridia and archegonia from plurilocular sporangia of some hypothetical green alga than to refer them directly to the plurilocular sporangia of brown algae. The spore mother cells of archegoniates are compared with the unilocu- lar sporangia of the brown algae, and the sporophyte of archegoniates with the thallus of brown algae. ScHENCK does not believe the sporophyte of pterido- phytes can be derived from that of bryophytes. Even the complicated antheridium of the Characeae is referred to the plurilocular sporangium of the brown algae— CHARLES J. CHAMBERLAIN. Translocation in green tissues.—RywoscH points out*? that translocation must depend upon the concentration gradient from the peripheral cells sg the vascular bundle. This gradient is due in part to the excess of food mace n the cells best illuminated, and also to the fact that transpiration cooperates doubly, by reducing the amount of water and by determining the movement of water. Thus those cells next the bundle are first to receive the water supply and those nearer the periphery are driest. He shows that the emptying of leaf tissues 15 not simultaneous, peripheral ones being emptied first, and that the whole process is greatly retarded when transpiration is checked. [Yet it must not be forgotten that there are plants in which transpiration cannot be invoked as an aid to trans- location, since it is practically non-existent for weeks or months at a stretch] The concentration is also kept low in the inner cells by the making of starch ae em. Rywosc# also adds a note on the function of the starch sheath, holding that its character as a reserve is very doubtful.—C. R. B. Hygroscopic living leaves. —HANNIG?3 reports what he says is the first recorded instance of the movement of living leaves produced by variations in the water- content of the cell walls. The leaves of various hardy species of ododendron Tise and fall, roll and unroll, according as they are subject to freezing and ers ing weather respectively, though the same movements may be produced by 0 conditions which reduce or increase the water-content of the cell walls. one 'S not concerned, HANNIG says, because dead or live, narcotized or unnarco si is not leaves exhibit movements equal in extent and kind. HANNIG’s argument 18 ™ convincing, and it seems unlikely that this conclusion is sound. In wee ons little is known of the physics of water and cell contents under the ieee . Loe : CRB to make it possible to state accurately the precise relations in eerie | 4 22 Rywoscu, S., Sur Stoffwanderung im Chlorophyligewebe. Bot. Zeit. O° 121-130. figs. 2. 1908. a ANNI rs ; Ein *3 Hanwic, E., Ueber hygroskopische Bewegungen lebender Blatter bet Ei von Frost und Tauwetter. Ber. Deutsch, Bot. Gessells. 26a: 151-106. © 1908] CURRENT LITERATURE 399 Development of Ulva.—The development and conjugation of gametes and also the germination of the zygote are described by ScHILLER*4 for both living and fixed materials. Three kinds of gametes are found in Ulva and also in Enteromorpha: (1) megagametes or giant gametes, which do not conjugate and are incapable of development; (2) parthenogametes, of medium size, which germi- nate into normal plants without any conjugation; and (3) microgametes, which are smaller than the parthenogametes and which produce new plants only after conjugation. The relation between the nucleus and the protoplasmic mass in the various gametes is believed to be the reason for the differences in behavior.— C S J. CHAMBERLAIN. Paleobotanical technique.—The veteran and distinguished Swedish paleo- botanist NarHorst has contributed remarkably to the technique as well as to the facts of that science. His most recent contribution to technique is in connec- tion with the use of collodion impressions of the surface of fossil plants for micro- Scopic study.?5 With the article are published photomicrographs made from such films, illustrating the structure of fossil fern sporangia, the epidermis of the leaves of ferns, and gymnosperms and angiosperms in a fossil condition. Even 4 Cupressinoxylon yields results with this method.—E. C. JEFFREY. A Paleocene flora.—M. PrerreE Marty of the Royal Belgian Museum of Natural History has published a memoir?® on the Paleocene flora of Trieu de Leval. Perhaps the most interesting feature of this publication is the discussion of the phylogeny of the important genus Quercus, 4 propos of the new species Dr yophyllum levalense. The latter has chestnut-like leaves and the author con- Cludes that among the living oaks it has its nearest affinities in those ancestral forms persisting in India, Japan, and the East Indies. The flora as a whole, with the above exception, presents a marked resemblance to that at present *xisting in northern South America.—E. C. JEFFREY. ae and Fungi of lowa.—BucHANAN?’ has brought together in convenient form, with keys, a list of the algae reported from Iowa, based upon the study of peaerous recent collections. The list includes 180 species, and the bibliography of “Towa Algae” includes nine titles. . _ The same thing has been done for the Erysiphaceae of Iowa by ANDERSON,’ including of course a complete list of hosts. ‘The recognized species and varieties sop 28, involving 35 synonymns; while the hosts reported number 187.— ba ae, Dr. Joser, Beitrage zur Kenntniss der Entwickelung der Gattung - Sitzungs> r, Kaiserl. Acad. Wiss. Wien 116:1-26. pls. I, 2. 1997- | Unt *S NaTHorsT, A. G., Ueber die Anwendung von Kollodiumabdruecken bei der *rsuchung fossiler Pflanzen. Arkiv fér Botanik 7:no. 4. 19°7- ers, Prerre, Mém. Musée Roy. d’Hist. Nat. Belgigique Sci oN, RoBeRT EartE, Notes on the algae of Iowa. . “PP. 40 (repaged). 1908. ™ ANDERson, J. P., Iowa Erysiphaceae. Idem 14:pp- 34 (repa ed). 1908. 521-51. 1908. Proc. Iowa Acad. 400 BOTANICAL GAZETTE [NOVEMBER Spermatogenesis in mosses.—The VAN LEEUWEN-REIJNVAANS add a few details to their former paper and announce their abandonment of this field of research,?9 after a brief excursion into it with rather startling results.3° Now they report centrosomes in the antheridial cells of Fegatella conica (contrary to BoLteteR) and in Pellia epiphylla (contrary to IkENo). In Mnium (sp. ?) they find (as in Polytrichum) in the last division from 8 to 4 chromosomes, 2 long and 2 short, which is a transverse (not diagonal) reduction.—C. R. B. Acorus Calamus.—This species was introduced into Europe in the middle of the sixteenth century, and it has always been known that the European plant produces no seeds. A study of the development of the pollen and embryo cast by Micxes' shows that both are so defective that the production of seeds is impossible. The reason for the sterility is supposed to be unfavorable climatic conditions.—CHARLEsS J. CHAMBERLAIN. Germination of zoospores.—Continuing his studies upon the spores of algae, SAUVAGEAUS? describes the germination of the zoospores of Cladostephus, Algao- zonia, and Cutleria. Methods of making cultures of zoospores are also dis- cussed.—C artes J. CHAMBERLAIN. 20 VAN LEEUWEN-REIJNVAAN, W. AND J., Ueber die Spermatogenese der Moose, speziell mit Beriicksichtigung der Zentrosomen- und Reduktionsteilungsfragen. Ber. utsch. Bot. Gesells. 26a: 301-309. pl. §. 1908. 3° Cf. Bor. Gazette 45: 358. 1908; 46:234. 1908. 3" Mtcke, M., Ueber den Bau und die cleat der Friichte und iiber die Herkunft von Dos Calamus L. Bot. Zeit. 66:1-23 32 AGEAU, CAMILLE, Nouv_lles observations sur la germination du ox Stephus Bienes Sur la germination des zoospores de I’ Aglaozonia melanoides Sur la germination ole aerints du Cutleria adspersa. Sur les cultures cellulaires d’Algues. Compt. Rend. 63: 698-704. 1908. fe ay sipioeay <2 j Oe ke n - F ter hd * Z ter More ia Bari clang i) : 2 ‘ ° A RP Nee glee wwid 4 * CAL GA December : | COULTER and CHARLES TANI JOHN M ‘ CONTE on of the R © Regi Nature of the Embt Al Che Botanical Gazette A Montbly Fournal Embracing all Departments of Botanical Science -faited by JoHN M. CouLTER and CHaARLEs R. BARNE Es, with the aad of other members of the otanical tae of the University of Chic Issued December 30, 1908 aang ol, XLVI CONTENTS FOR DECEMBER 1908 No. 6 - BRYOLOGICAL PAPERS. _ THE ORIGIN OF THE CUPULE OF MARCHANTIA. a CONTRIBUTIONS FROM THE HULL BOTANICAL goo, gaia 120 > (WITH FOURTEEN 4 ; FIGURES). Charles R. Pitack and W. /. G. Land - 401 "EMERGENCE OF LATERAL esi (WITH THREE FIGURES). Raymond H. Pond - - 410 STUDIES IN THE GRAMINEAE. THE GRAMINEAE OF THE ALPINE REGION M, OF THE ee. MOUNTAINS IN oh sa oie FIVE FIGURES AND PLATE 8) __. Theo. Holm 422 ne NATURE Spat aaa ee “~~ oF PEPEROMIA (WITH PLATES XXXI-XXXIII). William H. Bro - - . - - - - - 445 5 “BRIEFER ee cs. A NEw Potsonous MusHROoM (WITH TWO FIGURES). Geo. F. Atkinson : - - 461 AFFINITIES OF PHYL egy ses Cone FROM THE dices pest pe Aor RATORY 121. WV. Johanna Kildahl 464 NOTE ON THE POLLEN OF MICROCACHRYS. ‘Robert Boyd hinthn - - - - 465 RRENT LITERATURE BOOK REVIEWS - - . - - - < = . 2 iA - 467 NORTH AMERICAN UREDINEAE 68 NOTES FOR STUDENTS . ee | ks Siete ne ae pe ee ee ae The Botanical Gazette is published monthl The subscription price is $7.00 per year; the price y. [The subscription p Pp single gl is Ae cents. Geol. Survey 6: No. 1. 1880. Botanical Gazette, vol. 46] ie 1908} HOLM—ALPINE GRAMINEAE 423 elevations. According to this author 58 of these species occur also in the European and Asiatic mountains, or in high northern latitudes of both hemispheres. He enumerates 9 Gramineae. Among the 168 species of flowering plants I collected in this region only 17 belong to the Gramineae. The largest family is the Compositae with 25 species; then follow the Cyperaceae with 20, and then the Gramineae. Just above timberline the vegetation is luxuriant to the full extent of the word, and a number of very different plants abound in the willow- thickets along the mountain brooks; at higher elevations we may observe a rich vegetation on the slopes, especially near the snowbanks; but when we cross the bowlder fields we meet only with a very scant, often extremely poor, vegetation. Among the plants which were observed on the very summit of these mountains may be mentioned Poa Lettermanni, Festuca ovina supina, Claytonia megarrhiza, Stellaria umbellata, etc., but none of the Cyperaceae. It seems as if the Gramineae are able to thrive at very high elevations, judging from the various records of alpine plants in Europe and Asia, as will be shown later. It might be stated at the same time that some of these are among those that occur in the most northerly points; for instance, Alopecurus alpinus at 83° 4’, Poa flexuosa at 82° 50’, and Festuca brevifolia at 82° 27’. In the accompanying Table (I) I have enumerated the alpine species of Gramineae, which I collected on the following mountains: Long’s Peak, James’ Peak, Pike’s Peak, Mt. Elbert, Mt. Massive, Mt. Kelso, Gray’s Peak, and along the headwaters of Clear Creek. To these may be added Deschampsia calycina Presl. from the summit of Gray’s Peak, collected by B. H. Surra; and Poa Pattersoni Vas. from mountains near Gray’s Peak, collected by H. N. PATTERSON. The altitude where these alpine species occur lies between 335° and 4300™, Agrostis canina var., A. varians, Avena Mortoniana, Poa flexuosa, P. gracillima, P. Fendleriana, P. Lettermannt, fe. Pattersoni, P. alpina, Festuca ovina supina, Deschampsia calycina, Agropyrum Scribneri, and A. violaceum are in Colorado confined to the alpine region. The remaining species, on the other hand, were also observed at lower elevations, from the aspen zone (about 2500™) to the spruce zone (about 3100™). Phiewm alpinum, for instance, descends to the aspen zone on Long’s Peak, where’ it is very frequent 424 BOTANICAL GAZETTE [DECEMBER in swamps; Calamagrostis purpurascens follows the creeks throughout the spruce zone on Long’s Peak and the region of Clear Creek Canyon; C. canadensis acuminata is only exceptionally alpine, and thrives best in the swamps of the aspen zone; Deschampsia caespitosa is most frequent and typically developed in the swamps of the aspen zone, TABLE I ses n J P S)2l/¢lglalal3l® Alpine Gramineae from Colorado Ste L® ei) ee ee - ~|/B8)/2/R |/Al/ 4] eige EI BP Roh st os a ee A{/S/e 1S) a] a] o |e eee eerenns Fe es mi ate ee : “ Agcosbs varians Trin. ....;............... op + ae, BE oe os Dee WO GS res HEE, Pees . a Calamagrostis purpurascens R. Br......... aa ee ie Bp = C. canadensis acuminata Vas.............. = Noa Se oh, ce hampsia caespitosa Beauv............ + “4G 2 e Trisetum subspicatum Beauv.............. > +} + fe : Avena Mortoniana Scribn................. + Sets cay (i s re Poa rupicola (Vas.) Nash................. P Bie Ee Ee ‘ Be MRE il cs = ge ee 3. ~ ee Wee ee fee es + : P. Fendleriana (Stend.).......--........., oe ae - me Sib ELT wa eoremanting Vas... 233... Coe. Gh ee ee . Festuca ovina L...... Se ee Mie hue ks +i+ +p} + A ¥. ovina supina Hack... .o65.... - wn ale ge e Agropyrum violaceum Lge................ Ree San gs ar -* A. Scribneri Vas........ es +] + +].. © ee * A + indicates the presence of the species, dots its absence. but it is also very common near the snowbanks at high elevations; Trisetum subs picatum does not descend much farther than pac’ the timberline; Poa rupicola descends to the aspen zone on James F and near Central City, but only seldom; Festuca ovina was ae in the aspen zone near Central City, and in the spruce zone on *"" Massive and Long’s Peak. : The distribution of these alpine species on the Pacific and Atlantic coasts is shown in Table II. : It will be seen from this list that of the 20 alpine species from Colorado 13 occur also on the Pacific coast, and 7 on the Atlantic, where they are either alpine or arctic, with the exception of Des _ sia calycina, Only 9 of these occur also in the Old World. Table 1908] HOLM—ALPINE GRAMINEAE 425 shows their distribution in the polar regions, in the northern parts of Europe and Asia, but south of the arctic, and in the mountains farther south. TABLE II Pacific Atlantic Phieum alpinutii 140.) < coca oa 2 + + Agrostis varians:. =. fe + Calamagrostis purpurascens......| 3s C. canadensis acuminata......... ie + Desehampsia caespitosa os -s D. COWGINE: .. ivadec tee oh Trisetum subspicatum........... + + Of MOXZUOBA:. 55 ose op es a = 2 2 P, praciling; . ocd. es h + . P:. Fendleriana: 2.3 ce + . PUR. seks ccna eee ae 5 P.. Levers 5. os a + + Festuca ovina supina...........- a + TABLE III 3 2 POLAR REGIONS a 5 = = Sia a ne - | z Bilale ao) g 3) r=) Sj se | i e|/ zl es S ai tig! §123).615., < g e a a/eaej}%v 2 Fs 8g a | a : 22 | a ai/2{s ae ee = 8 3 Sil alse SI StS Era) £1 ei ees erSi #12, a 2(S(/lela|2/a] 8 ,e/o} <1 Oo) a] Rls Phleum alpinum......... +1 +1 + li #1 +e ei tt Ctemarn ostis purpuras- MG ne oe Peschainpsia cacspitosa |. | 2. (cf et] ¥] $e) 4] Fe tl tl tts Pp, ctum subspicatum +) ee] +P +] +] 4+) 4+] t]-- + oe hese 4 9 ange +i/+{ +] 4] 4+} 4] 4+] 2] = Ree Ga tee F es el eho Eel ef ere err rrr es 63 . eee + | eb ed ee OL eb el wae Be Agro Supina iG ee eee ee ee ee ee tee ee oe ee Pyrum violaceum....| + | + | ..{ + [| «[--ftf-.d efor} tq Se agree caer a a ONE AONE TNR, SOMMONS Poaceae ants bgt Ure” SGD IS Le SS OS aa aE TOU Four of these are circumpolar: Trisetum subspicatum, Poa flexuosa, - alpina, and Festuca ovina, also the vat. supina. Calamagrostis Purpurascens is the only one that is confined to this confinent and Greenland ; Agropyrum violaceum occurs in the arctic Tegions of both hemispheres, and var. supina of Festuca ovina is also an inhabit- ant of these high northern regions outside America. All the others €xtend to the mountains farther south, and five of these have even 426 BOTANICAL GAZETTE [DECEMBER reached the Himalayas. According to CHEESEMAN,? Deschampsia caespitosa macrantha Hack. and Trisetum subspicatum occur in New Zealand, and the latter has also been recorded from the antarctic regions. Deschampsia caespitosa is in Arctic America, Greenland, Novaja Zemlja, and Arctic Siberia, mostly represented by vars. brevifolia Trautv. and borealis Trautv. Agrostis canina occurs in Greenland and in several forms, but the variety which I collected in Colorado is not among these. Professor HackEL, who has kindly examined my specimens of Agrostis, thinks that my alpine A. canina is nearest to var. pusilla Aschers. et Graebn. Tables II and III thus demonstrate the fact that the alpine Gra- mineae in Colorado represent an assemblage of several very distinct geographical types: some that are endemic to this particular region; some that occur also on the Pacific and Atlantic coasts; some that have reached the polar regions in certain parts of both hemispheres; some that are circumpolar; and finally some that have become dispersed throughout the mountainous districts farther south in Europe and Asia. Of the 20 species enumerated from the mountains of Colorado, 7 are arctic-alpine types. Deschampsia caespitosa and Festuca ovina are quite frequent in these alpine and arctic regions, but their widest distribution is within the lowlands of the temperate zones of both hemispheres; hence they are not “arctic-alpine”’ in the strict sense of the word. The tribes that are thus represented in this alpine region are AGROSTIDEAE (5 spp.), AVENEAE (4 spp.), FESTUCEAE (8 spp-), and HorbEAE (2 spp.). They are represented by genera that are really cosmopolitan, and from Table III we have seen that some of the species are widely distributed in both hemispheres. These data alone might suffice to illustrate the principal points in regard to compo sition and geographical distribution; but in order to make the illus tration more complete, it seems necessary to extend our comparison to the grass vegetation in the timbered belts and on the plains below; also to the vegetation of alpine regions of other mountains. ad Beginning with the species of the spruce zone, it has been stat that some of the alpine species are found among them, where they become associated with a few types characteristic of the zones ? CHEESEMAN, T. F., Manual of the New Zealand flora. 1906. 1908] HOLM—ALPINE GRAMINEAE 427 with some others which are common also to the aspen zone below. The following were observed only in the spruce zone: Sporobolus brevicalyx Scribn.., Calamagrostis Langsdorfii (Link) Trin., C. Scribneri Beal, A grostis humilis Vas., Poa reflexa Vas. and Scribn., and Festuca ovina pseudo-ovina; while Poa pratensis L. was also collected in the aspen zone. If we continue the comparison, and examine the species that occur in the aspen zone, we meet with a larger number of species of the same tribes that were observed at higher elevations, and with them there also occur some of the Chlorideae. Peculiar to this zone are: Stipa minor Scribn., M uehlenbergia comata Benth., M. gracilis Trin. and the Var. breviaristata Vas., Alopecurus aristulatus Michx., Sporobolus depauperatus (Torr.) Scribn., Agrostis exarata Trin., Trisetum monianum Vas., Koeleria cristata Pers., Glyceria americana (Torr.), G. Holmii Beal, Poa annua L., P. nemoralis L., Festuca Thurberi Vas., Bromus breviaristatus Thurb., B. Richardsonis Link, Hordeum no- dosum L., Elymus Sitanion Schult., and E. brevifolius (Sm.). Besides these there are a few species which occur here, but which more prop- erly belong to the plains, where they are more abundant and more typically developed. These are Agrostis scabra Willd., Schedon- nardus texanus Steud., Bouteloua oligostachya Torr., and Atropis Mroides (Nutt.). The number of species of Gramineae observed in the mountainous regions, from the aspen zone to the summits, aver- ages about 50, among which the Chlorideae are rather scantily repre- sented, aoe mis Descending to the plains, at an elevation of 1500™ about 4o “pecies belonging to the same tribes are found; the Andropogoneae and Paniceae are added; and the Chlorideae abound. The follow- Ing species are very frequent: Panicum virgatum L., P. capillare L., Aristida fasciculata Torr., Stipa comata Trin. and Rupr., S. viridula tin., Eriocoma cuspidata Nutt., Cenchrus tribuloides L., Sporobolus ‘ryptandrus Muehl., S. asperifolius Thurb., S. atroides Torr., Cala- movilfa longifolia (Hook.) Hack., Agrostis scabra Willd., A. interme- dia Scribn.; A. ‘alba L., Schedonnardus texanus Steud., Bouteloua oligostachya Torr., B. racemosa Lag., Buchloé dactyloides Engelm., lunroa squarrosa.(Nutt.) Torr., Distichlis spicata (L.) Grne., Atropis “roides: (Nutt.), Poa Buckleyana Nash, Festuca tenella Willd., Agro- 428 BOTANICAL GAZETTE [DECEMBER pyrum occidentale Scribn. vars. mollis and vivipara, A. tenerum Vas., A. spicatum Pursh, Hordeum jubatum L., and Elymus canadensis L. Some others are more scattered, for instance: Andropogon furcatus Muehl., Echinochloa crus-galli (L.) Beauv., Muehlenbergia glomerata Trin., Lycurus phleoides H. B. K., Setaria glauca L., Bouteloua prostrata Lag., Diplachne fascicularis (Lam.) Beauv., Eragrostis major Host., etc. This grass vegetation in the wooded belts and on the plains con- sists mostly of American types, and the very few species that are also represented in the Old World are mostly introduced, for instance: Echinochloa crus-galli, Digitaria glabra, Setaria glauca, Eragrostts major, and Agrostis alba. Calamagrostis Langsdorfii, which I found in the spruce zone on Mt. Massive, occurs also in the mountains of New England, Canada, Alaska, south to California, and is also an inhabitant of Europe and Asia. Poa annua, P. nemoralis, P. pra- tensis, and Koeleria cristata, widely distributed species in the Old World, especially in the lowlands of the cold temperate zone, are also represented in the aspen zone. P. nemoralis is very common an varies according to the substratum, whether dry rocks or rich soil, in thickets, along streams, etc. ; In comparing the geographical distribution of these various species of Gramineae which occur in the alpine region, in the wooded belts of the mountains, and on the plains, it is noticeable that the genera of the alpine flora are more cosmopolitan than those of the lower levels. None of the genera of the alpine Gramineae a7 endemic, and about one-half of the species occur also in the Old World (cf. Table III). On the other hand, the presence of arctic and circumpolar species is characteristic of the alpine flora, Sper which may be regarded as remnants of an old glacial vegetation that migrated from the far north; but those endemic in Colorado may have developed in the alpine regions of these very mountains. Let us now examine the grass vegetation of the alpine eit of the Alps of Switzerland, the Pyrenees, the mountains of Norway» the Caucasus, and the Himalayas. In these mountains the ae that occur in Colorado are found, besides the Phalarideae, of we a Hierochloa laxa Br. has been reported from the Himalayas (5000")s and Anthoxanthum odoratum L, from Switzerland and the Caucast® 1908] HOLM—ALPINE GRAMINEAE 429 In the Alps of Switzerland the tribe Festuceae is the best repre- sented, according to Heer.’ There are four species of Festuca (F. ovina L., F. pumila All., F. pilosa Hall. fil., and F. Halleri Vill.) and five of Poa (P. alpina L., P. caesia Sm., P. laxa Hnke., P. minor Gaud., and P. annua L.). Koeleria hirsuta Gaud., Sesleria coerulea L., and SS. disticha Pers. also are present. Four Aveneae occur here (Avena distichophylla Vill., A. versicolor Vill., Deschampsia caespitosa Beauv., and Trisetum subspicatum Beauv.); two small species of Agrostis (A. rupestris All. and A. alpina Scop.) represent, with Phleum alpinum L., the Agrostideae; while Nardus stricta L. is the only member of Hordeae, observed so far, in'these regions. Of these species Sesleria disticha and Poa laxa have been recorded from the highest elevation (3000). In the Pyrenees‘ the genera are about the same, with the addition of Holcus caespitosus Boiss. (Aveneae), Molinia coerulea Moench., and Nardurus Lachenalii Godr. (Festuceae).. The Festuceae are here also best represented, numbering 17 species, among which the following are known also from Switzerland: Sesleria disticha, Festuca Halleri, F. pumila, Poa laxa, P. caesia, P. minor, and P. alpina. Among the Agrostideae, Agrostis rupestris and A. alpina are here accompanied by three other species: A. setacea Curt., A. mevadensis Boiss., and A. capillaris L., while Phleum alpinum is only known from the subalpine region of these mountains. The Aveneae are Tepresented by Deschampsia flexuosa, while D. caespitosa occurs only at lower elevations; also by Avena albinervis Boiss., A. Scheuch- zerti All., Holcus caespitosus Boiss., Trisetum flavescens Beauv., fT; velutinum Boiss., T. glaciale Boiss., and T. Gaudinianum Boiss., while 7. subs picatum does not reach the alpine region in these moun- tains. The Hordeae are also here only represented by Nardus stricta, In the mountains of Norway’ the alpine Gramineae number only 8 species: Phleum alpinum, Aira alpina L., Trisetum subspicatum, Catabrosa algida F r., Poa laxa, P. stricta Lindeb., P. flexuosa Wahl., and P. alpina, all of which extend to the arctic region. * HEER, O., Ueber die nivale Flora der Schweitz. 1883. 4D. Mariano pet Amo y Mora, Flora Fanerogdmica de la Peninsula Iberica. Granada 1:2. 1871. ‘Biyrr, M. N., Norges Flora. Christiania. 1861. 430 BOTANICAL GAZETTE [DECEMBER According to MEYER® 22 Gramineae are alpine in the Caucasus. Of special interest are Phleum alpinum, Avena versicolor, Deschampsia flexuosa, Trisetum flavescens, Poa alpina, Koeleria cristata, and Festuca ovina. Besides these it is interesting to notice the occurrence of Calamagrostis caucasica Trin., Briza media L., Poa altaica Trin., Colpodium Steveni Trin., and Hordeum pratense Huds. If we extend the comparison to the Himalayas,’ we notice the pres- ence of 5 alpine species which occur also in Colorado (cf. Table III); also the occurrence of genera that are not represented in the other mountains, namely Hierochloa, Stipa, Deyeuxia, Danthonia, and Elymus (E. sibiricus L.). The very considerable elevation of 5500” is in these mountains reached by Trisetum subspicatum, Poa hirtiglumis Hook. f., and Elymus sibiricus L.; from between 4500 and 5100™ the following are recorded: Hierchloa laxa Br., Agrostis inaequiglumis Griseb., Deyeuxia compacta Munro, D. nivicola Hook. f., D. pulchella Hook. f., Deschampsia caespitosa, Catabrosa sikkimen- sis Stapf, Poa alpina L., P. attenuata Trin., P. nemoralis L., P. flexuosa Wahl., P. tremula Stapf, and Festuca valesiaca Schleich. Two species of Stipa (S. concinna Hook. and S. mongolica Turcz.) ascend to an elevation of 4000™. The Himalayas are thus much richer in alpine types than any of the other mountains, a fact that becomes still more manifest when we compare the representatives of the other families. Nevertheless, the alpine Gramineae of the Himalayas do not possess any type whic from a biologic point of view deviates to any great extent from those of Colorado. For instance, Stipa and Elymus are really the only alpine genera in which the structure of spikelets is quite distinct from that of most of the others. It seems: altogether as if the alpine Gramineae are remarkably uniform in habit, and in is Structure, xo ae In speaking of Colorado especially, we have not in the alpine region a single type that may be compared with Buchloé, Munro®, Sporobolus, or Distichlis from the lowlands. The alpine rere tives are perennial, except Deschampsia calycina; they are met ind. © MEYER, Verzeichniss der Pflanzen, welche im Caucasus etc., gefunden si” St. Petersburg. 1831. 7 HOOKER, J. D., Flora of British India. London. 1894. Vol. 6. 1908] HOLM—ALPINE GRAMINEAE 431 caespitose or sometimes stoloniferous, but with simple culms, and with an inflorescence (spicate or paniculate) of the usual composition. The empty glumes show no peculiar structure, and the flowering glume is either awned or awnless, and not in any way different from the usual structure among grasses in general. The average height of these alpine Gramineae is in some cases much less, in other cases. about the same as that of lowland species of the same genera. Poa Lettermanii, the species of Agrostis, and Festuca ovina are mere dwarfs, but Agropyrum Scribneri reaches a height of 50°™, even at an elevation of 4ooo™. Agropyrum violaceum at the same altitude has culms about 40°™ high; and the culms of Deschampsia caespitosa, Calamagrostis purpurascens, and Poa gracillima reach about the same height. In habit the alpine Gramineae do not exhibit any character- istics which might indicate the extreme conditions under which they live. The same is the case with those grasses that occur in the arctic tegion, where we meet with several species that do not occur farther south, but the habit of these is of the same general kind. It is very different with the representatives of most of the dicotyledonous families from the alpine and arctic regions; in these the habit is frequently so peculiar and characteristic that they are readily recognized as being either alpine or arctic. In other words, the monocotyledons, at least the Glumiflorae, do not appear to be influenced to any great extent by climate and soil, as are most of the dicotyledons, at least not in regard to their general habit in alpine or arctic regions. An examination of the internal structure of these alpine species from Colorado will demonstrate probable characteristics in structure; “probable,” because I am not in a position to make any comparison with species from other alpine regions. It is my intention merely to present these anatomical data for future comparison, when some- one may feel induced to investigate the grass vegetation of other Mountains, and especially from high altitudes. I have examined Toots, culms, and leaves. The leaf structure might have been suffi- Cient, and, as already stated, most authors have so far confined their Work to the leaves alone. However, it does not appear to me that the structure of culms and roots should be neglected altogether, and especially not when dealing with plants that are able to persist under Such extreme conditions. : 432 BOTANICAL GAZETTE [DECEMBER The roots : In considering the internal structure of roots that are simply nutri- tive and of no long duration (perhaps only one season), we must not expect to find great modifications. In regard to the Gramineae we have learned from Kurncr’s® interesting paper that certain modifications may be observed in the structure of the cortex, whether persisting or collapsing, whether homogeneous or differentiated as distinct zones of parenchymatic or stereomatic strata; also in the thickening of the endodermis, and in the structure of the pericambium, whether it is continuous or interrupted by the proto-hadrome. The presence or absence of an exodermis also seems to be worth mention, and the structure of the parenchyma in the stele, which sometimes represents a central pith. Much attention has been given to the position of the proto-hadrome vessels, whether they are inside the pericambium or border directly on the endodermis. In some instances all these vessels have been observed to occupy the same position in reference to the pericambium; but in other instances a variation has been noticed, where only some of the proto-hadrome vessels had broken through the pericambium. In studying root structures: of different plants, especially of monocotyledons, one gets the impression that the continuity or interruption of the pericambium is of some 1° portance and constitutes a good anatomical character. In very many roots I have found a constantly continuous pericambium oF @ constantly interrupted one; but on the other hand, as shown ™ Eriocaulon and Carex,® there are also cases where this structure is not constant, but varies from the base to the apex of the same root. This peculiarity I noticed by making consecutive sections of a number of roots, and it appears therefore as if the structure of the pericambium, ‘so far as concerns its continuity or interruption, is not a character 1° be depended upon. In Deschampsia caespitosa and Festuca diages from Europe, KiincE (I. c., p. 56) observed the proto-hadrome vessels bordering on the endodermis; while in these same epee from Colorado all the vessels were found to be inside the pericam * i i oe 8 KLINGE, Vergleichend histiologische Untersuchung der meg es Imp- Cyperaceen-Wurzeln insbesondere der Wurzel-Leitbiindel. Mém. rs St Petersbourg VII. 26: No. 12. 1879. . ° Bor. Gazetre 31:17. 1901; and Am. Journ. Sci. 102278. 1900- 1908] HOLM—ALPINE GRAMINEAE 433 bium. Such discrepancies often occur, but they are hardly of any im- portance. In the alpine Gramineae from Colorado the root structure is very uniform. The epidermis is hairy in all the species; a thin- walled exodermis was observed only in Agropyrum violaceum. The cortical parenchyma is mostly thin-walled and solid, but a radial collapsing was noticed in the species of Poa, with the exception of P. alpina, in Trisetum, and in Deschampsia. In the species of Agropyrum the peripheral strata of the cortex are stereomatic, and persistent in comparison with the inner, which are thin-walled and collapsed. The endodermis is generally thick-walled (figs. 1-5, End), Tepresenting a typical U-endodermis, or an 0Q-endodermis, as was observed in specimens of Poa alpina from bowlder fields. The pericambium was found to be continuous in all the species, and it is generally thin-walled; but in the species of Agrostis (fig. 2), Calama- grostis, Trisetum, and in Poa gracillima it is more or less thick- walled. It consists mostly of a single layer, but in the species of Agropyrum (fig. 5) and Avena two or three layers are developed outside the proto-hadrome vessels. ‘The number of hadromatic rays is of course very variable; in the thick roots of Trisetum, Deschampsia, Calamagrostis, Avena, and Agropyrum there may be as many as teen rays, but with mostly a single proto-hadrome vessel in each Tay. In the species of Agrostis and Festuca the hadrome extends to the center of the stele, while in the others a central pith is developed. This pith is quite broad, and often conspicuously thick-walled, as in Trisetum, Agropyrum, Avena, and Calamagrostis. It is interesting to note that in some cases the root structure Corresponds with the nature of the substratum. For instance, In Poa Lettermanni, which I found growing in wet moss near the Snowbanks, the root structure resembles that of a hydrophilous Plant, with open cortex, thick-walled endodermis, and thin-walled Pericambium. In the species of Agropyrum from very. dry, stony Soil, the peripheral strata of the cortex are stereomatic. In Cala- Magrostis purpurascens from similar stations there is a very compact ‘ortex, a heavily thickened endodermis, a thick-walled pericam- bium, and a broad central, very thick-walled pith. A similar, very Solid structure is also characteristic of the species of Festuca and 434 BOTANICAL GAZETTE [DECEMBER Agrostis, inhabitants of dry soil among bowlders. The roots of these species thus show in general the structure of xerophytes. But in Poa alpina no such distinction seems feasible, since the struc- ture is identical whether the specimens are from wet soil in thickets of willows along mountain brooks, or from dry soil among bowlders. The culm In describing the structure of the culm, attention must be given to the distribution of the mechanical tissue (stereome), to the minor structure and disposition of the mestome strands, and finally to the structure of the cortical parenchyma. In the character of the stereome our alpine Gramineae represent the type in which a circular band of this tissue (in cross-sections) is in contact with all the mestome bundles; it is the eleventh type of SCHWENDENER’? and is the one most frequently observed in the Gramineae. While the principal feature of this type is that all the mestome strands are in contact with the. mechanical tissue, some modifications are to be observed in regard to the relative development or strength of the stereome, especially n cases where the mestome bundles occur in different sizes, and in more than one circular band. Five very distinct modifications Lae observed in our alpine species, which may be readily distinguishe by the accompanying figures, which I have drawn in a schematic way. The black represents the stereome; the peripheral white zone the cortex; the central white zone the pith; the orbicular and oval rings the mestome strands. In these figures, A represents the most simple structure, where there are only five mestome strands, all the same size and outline (oval), and all imbedded in the stereome, which extends to epidermis, thus forming a strong, hypodermal support outside the leptome (Agrostis canina, var.). In B there are four large, oval mestome strands, alternating with four much smaller ones, which are orbicular in transverse section, and they are all surrounded by stereome, whi ; only extends to the epidermis outside the larger ones (Poa Letter apes P. alpina from Long’s Peak, and Agrostis varians). In C ( a rupicola) there is also one band of mestome bundles, composed ° t0SCHWENDENER, Das mechanische Princip im anatomischen cn in Monocotylen 60. Leipzig. 1874. 1908] HOLM—ALPINE GRAMINEAE 435 larger (oval) and smaller (orbicular) ones; and hypodermal stereome occurs outside each of the mestome strands, but is only in contact with the leptome side of the larger ones; the smaller strands only touch the inner stereome with their hadrome side. When two con- centric bands of mestome bundles occur, the peripheral ones are the smallest and are orbicular in cross-section; the inner ones are either e - Diagram showing the structure of the culms of Agrostis canina var. (A), Poa Lettermanni (B), P. rupicola (C), P. alpina (D), and Agropyrum violaceum (£). Orbicular (D) or oval, often representing two sizes, as shown in E. Nn these culms (D and E) the stereome shows two well-marked Modifications. It constitutes a mechanical support on the leptome Side of all the mestome strands in D; while in E this hypodermal Support is confined to the peripheral strands alone—those of the inner band (E) are imbedded in a zone of stereome, which does not €xtend to epidermis. The structure illustrated by E was observed In_ Calamagrostis purpurascens, Agropyrum violaceum, and Des- champsia caespitosa from Graymont; while D is the most frequent 436 BOTANICAL GAZETTE [DECEMBER structure exhibited by the remaining species, including Poa alpina from Mt. Kelso and Deschampsia caespitosa from Gray’s Peak. These culms thus represent five types as to the occurrence of one or two bands of mestome bundles, and as to the distribution of the stereome as a circular band extending to the epidermis as hypoder- mal groups in contact with or separated from some of the mestome bundles (the latter case is illustrated in C). The fact that two of these types (D and E) have been observed in one species (Deschampsia caes pitosa), though from different elevations, seems to indicate that the structure may not be constant. The type D appears to be the most frequent in the alpine species of Colorado, and the most important difference between this and the three preceding (A, B, and C) depends upon the presence of two concentric bands of mestome bundles, all of which are supported by hypodermal stereome. The type E is more complicated on account of the inner mestome strands being of different size and lacking the hypodermal stereome, and this type, as stated above, was observed in Agropyrum violaceum. If this structure be compared with that of the French species of Agropyrum described by DuvaL-JouvE, it is observed that it does not agree with any of them. The species examined by this author were lowland species, and several were maritime. Character- istic of these species is the occurrence of hypodermal stereome outside the smaller as well as the larger mestome strands; also in some species the inner band may be located nearer the center of the culm, a com siderable distance from the stereomatic zone. In other words, the lowland species of Agropyrum in France represent actually an entirely distinct type of structure, which corresponds with the twelfth type of SCHWENDENER (J. c.), in which the inner mestome strands are in the pith, some distance from the stereomatic cylinder. The minor structure of the mestome strands in our alpine spe’ agrees in most respects with that of other Gramineae. It has — shown that some variation occurs in the outline of cross-section some being orbicular (especially the smaller ones), and the large? Ones usually oval. The leptome and hadrome differ in no Way suite that of other species from lower elevations. A more or less thick- *t Duvat-Jouve, Etude anatomique de quelques Graminées et €M particulier des Agropyrum de l’Hérault. Mém. Acad. Sci. Montpellier. Paris. 1879- 1908] HOLM—ALPINE GRAMINEAE 437 walled mestome sheath was observed in all the alpine Gramineae, and these species may thus be added to the list given by SCHWENDENER®? in his paper on mestome sheaths. However, the presence or absence of the mestome sheath, as already pointed out by SCHWENDENER (/.¢., p. 415), is merely of taxonomic importance. This may be readily seen from his list, according to which this sheath is not devel- oped in any of the species of Andropogoneae and Maydeae, or in certain genera of the Paniceae (Paspalum, Pennisetum, and Setaria). The fact that it occurs in some species of Panicum (P. miliacewm, P. capillare, P. proliferum), but not in others (P. sanguinale, P plicatum, P. colonum, etc.), seems to indicate that these species repre- sent very distinct types within the genus, as shown also by the external structure of their spikelets. The same conclusion may be drawn from the fact that the species of Aristida in which I observed a double paren- chyma sheath,"s but no mestome sheath, differ in a marked degree from those which possess this sheath, and in which only a single paren- chyma sheath is developed; we have here to deal with a taxonomic, and not with an epharmonic character. By studying the anatomy of a number of Gramineae allied to or associated with Aristida, I found a mestome sheath constantly developed, whether the material was collected on the plains, the prairies, in woodlands, or in marshes. If on the other hand the structure of the mestome sheath is examined, some kind of modification in the thickening of the cell walls is noticed, which evidently constitutes an epharmonic character; in the alpine Species this sheath was generally observed to be quite thick-walled. The presence or absence of thick-walled mestome parenchyma as a Stratum between the leptome and the hadrome is to be considered only of taxonomic importance; such parenchyma was not observed in Poa Lettermanni, P. gracillima, P. rupicola, or in the species of Festuca and Avena, but in all the others. Of much greater interest, however, is the structure of the cortical Parenchyma. This tissue is very compact in these Gramineae with the exception only of Poa Fendleriana, P. gracillima, and Phleum es It is either developed as a palisade tissue of several layers NDENER, Die Mestomscheiden der Gramineenblatter. Sitgungsber. Berliner Akad. Wiss. 413. 1890. *3 Hotm, THEO. Some new anatomical characters for certain Gramineae. Beih. Bot. Centralbl. II:—. Igor. 438 BOTANICAL GAZETTE [DECEMBER (fig. 6, C) or as a homogeneous tissue of roundish cells (in cross- section). The former structure is the most frequent, and especially well represented in Poa rupicola, P. Lettermanni (fig. 6), and Agrostis canina; the latter structure was observed in Agrostis varians, Poa flexuosa, Agropyrum, Calamagrostis, Deschampsia, and Festuca. We will finally consider the structure of the cuticle and epidermis. The cuticle was observed to be smooth and quite thick in all the species, even in the densely hairy Trisetum. The epidermis is scabrous in Calamagrostis, hairy in Trisetum, but glabrous in the others. Some slight variation in the structure of the cell walls was noticed; the outer wall, for instance, is quite thick as compared with the inner and the radial, and this structure seems to be the most fre- quent. But in Agrostis canina, Poa rupicola, Phleum alpinum, and Agropyrum violaceum all the cell walls of epidermis were equally and quite heavily thickened. : A very firm structure is thus exhibited by the culms of our alpine Gramineae, so far as concerns the mechanical tissue and the dense cortical parenchyma covered by a thick-walled epidermis. It 3 also interesting to notice that the cortex generally contains much chlorophyll, and that the cells are developed as typical palisades, thus being able to perform the function of the chlorenchyma in the leaves. The modifications in structure in the culms depend mostly upon the distribution of the stereome, and upon the mestome strands (their relative size, their mechanical support, and their disposition in one or two concentric bands). The pith, on the other hand, shout © deviation from the most common structure known in this family; it was constantly found to be thin-walled and broken in the center, and with no deposits of starch. The leaves : In the leaves the epidermis and chlorenchyma offer some saanr’ tions of importance, and much more so than the stereome, at least 9 the alpine species. However, the structure is very uniform, ee not exhibit any such prominent epharmonic characters as are uae known from species of the lowlands, the plains, and the pra” In the alpine species the leaf structure is very firm throughout; a are no wide intercellular spaces in the chlorenchyma, and no W 1908] HOLM—ALPINE GRAMINEAE 439 storage tissue surrounding the veins. The distribution of the stereome is mainly the same in all the species and rather scantily represented as compared with the culm. The mestome strands are constantly arranged in a single plane and are very uniform in structure. In the epidermis the outer cell wall is generally quite thick on the dorsal face, but less so on the ventral; the cuticle is smooth, and very distinct in all the species. The characteristic bulliform cells between the mestome strands on the upper face of the blade were observed in all the species, but they are not very large, and are sometimes confined to a single group, one on each side of the midrib, as in Poa Letter- manni, P. flexuosa, P. gracillima, and P. rupicola; in the other species there may be four to six or even a larger number of groups in the lateral parts of the leaf blade. In Poa Lettermanni (figs. 7, 8) the leaves are glabrous on both faces, but in the other species they are generally a little scabrous from small, obtuse papillae. Pointed, prickle-like projections occur in Festuca, Agrostis, Poa rupicola, P. Fendleriana, and P. alpina from Long’s Peak. Hairs are not frequent, but were observed on the ventral face of the blade in Poa gracillima, Calama- grostis, and Avena, and on both faces in Trisetum and Agropyrum Scribneri. With the exception of Trisetum subspicatum, which may be called densely hairy, the hairs in the other Gramineae are so scat- tered that they are often hardly visible to the naked eye. The stomata (fig. 7) occur mostly on both faces of the blade, but as a rule are most frequent on the ventral face; in some species of Poa, Agropyrum Scribneri, Calamagrostis, and Trisetum they are confined to the ventral face. They are usually sunk, and sometimes covered by papillae or hairs, and they occur especially on the sides of the furrows between the mestome bundles. Their position in reference to the surface may sometimes vary on the same leaf; for instance, in Agropyrum violaceum they are free on the ventral face, but sunk on the dorsal, while the opposite is true of Avena ; in Des- champsia caespitosa they are level with the epidermis, and not covered by the papillae. Otherwise the structure of the epidermis offers no Points of particular interest. The stereome is poorly represented in most of these species, and occurs often only as a very small hypodermal strand outside the larger mestome bundles (fig. 8) and not in contact with them; it is better 440 BOTANICAL GAZETTE [DECEMBER developed in the margins of the leaves. The mestome strands show the same structure in regard to the leptome and hadrome as observed in theculm; there is also the same variation from oval to orbicular (in cross-section), and the mestome sheath is typically developed with the inner cell wall heavily thickened. Outside the mestome sheath the ordinary thin-walled parenchyma sheath is found mostly contain- ing some chlorophyll. I have not observed a single instance in these alpine species where mestome strands occurred beneath the bulli- form cells; but in Deschampsia caespitosa from Graymont, at a much lower elevation, some few very fine veins were observed between the larger ones,-thus being located directly underneath the bulliform cells. It might be mentioned at the same time that Duvat-JOuvE (J. ¢., pl. 16, fig. 5) figures a leaf of a French specimen in which a very small mestome strand occurs between each of the two larger veins, just beneath the bulliform cells, The chlorenchyma is very compact in these alpine species, and is mostly developed as a palisade tissue. In Poa Lettermanni, however, it is developed as palisades only around the mestome strands, radiat- ing toward their center, while in the other portions of the leaf this tissue consists of much shorter and roundish cells (figs. 7,8). In Poa flexuosa there are no palisades at all ; in Phleum the cells are hardly high enough to be called palisades, even if some distinction may be noticed between the ventral and dorsal portion of the chlorenchyma. In all the other species the chlorenchyma constitutes a homogeneous palisade tissue, vertical to the surface or radiating toward the center of the mestome bundles. It is a very compact tissue throughout the leaf blade, and rich in chlorophyll. The leaves of the alpine Gramineae are mostly erect, though oe exactly vertical, and are frequently conduplicate or with the margins involute; they are seldom spreading or perfectly flat. In this way they agree to some extent with the species from the plains, although the internal structure is very different, at least in certain genera. In the alpine species the leaves are often furrowed on the ventral face, but not to the extent so commonly observed in the lowland species, 10 those that inhabit the plains for instance. This may perhaps be the reason why the stomata in the alpine species are so much deepet than in those from the lowlands, where they are level with the epidermis, but HOLM—ALPINE GRAMINEAE 441 protected by the more ample covering of papillae or hairs, and also by the greater depth of the furrows. In the leaves of the lowland species the stereome is better represented, the bulliform cells generally larger, and frequently accompanied by several strata of a colorless tissue, the so-called water-storage tissue, which is not developed in the alpine species. But in the chlorenchyma of the Gramineae from the plains and prairies we find a more or less homogeneous tissue of palisades occupying the position described above. Finally the fact must be mentioned that the stomata being most frequent on the ventral face of the leaf is a feature the alpine Gramineae have in common with nearly all those which I have examined from the lowlands, and especially those from the plains and prairies, with the exception of Sporo- bolus, Munroa, and Calamovilfa. In the woodland types of Muehlen- bergia the stomata are almost equally distributed on both faces of the leaf blade; while in the species of the same genus from dry, rocky mountain slopes, the stomata are confined to the ventral face and pro- tected by the folding of the blade. In species from wet soil, meadows, or swamps, the stomata are most frequent on the dorsal face in Leersia; while in Amphicarpum from moist pine barrens they are distributed over both faces, though most numerous on the ventral; in Uniola latifolia from shaded slopes the stomata occur only on the ventral face, and this same disposition is to be found also in Pleuropogon Sabinei from arctic swamps. Duvat-Jouve, who has examined a large number of Gramineae," speaks of the difficulty of giving any precise information about the distribution of stomata in this family. He observed also that the ventral face of the blade is sometimes the only One where the stomata occur, but at the same time he noticed that a torsion of the leaf took place, thus exposing the dorsal face to the sun instead of the ventral. In this way the stomata become well pro- tected, but in our alpine types the only protection seems to depend Upon = folding of the blade, conduplicate or with the margins involut The leaf structure of alpine plants has been described and explained by several authors, but the Gramineae have been neglected, and evidently because the narrow leaves appear to be more uniform in ut os Pech sin Histotaxie des feuilles de Graminées. Ann. Sci. Nat. Bot. E a 442 BOTANICAL GAZETTE [DECEMBER structure and apparently of less interest. Iam not in the position to draw any anatomical comparison, therefore, between the species from the Rocky Mountains and those from other alpine regions. The alpine types which have been treated and studied in Europe are nearly all dicotyledons, and the results are not quite comparable to those derived from the study of our Gramineae. According to BONNIER" and WaGNER,"® the palisade tissue should be far better developed in the alpine forms (dicotyledons) than in those from the lowlands; the leaves should be thicker, and the structure more open on account of the wider intercellular spaces; also the alpine leaves should be more thoroughly dorsiventral, with stomata sometimes more abundant on the ventral than on the dorsal face; the guard cells should be level with the epidermis except in species with evergreen leaves (Ericaceae, etc.). These distinctions are not to be observed in the Gramineae. We have seen that in the alpine representatives of this family the leaves are not dorsiventral; the palisade tissue is not developed to any greater extent than in the lowland species; the chlorenchyma is not open, 07 the contrary it is very compact; also the stomata are not level with the epidermis but mostly sunken. It seems almost safe to conclude that the epharmonic characters are much less pronounced in the alpine Gramineae than in the dicotyledons from similar high situations, when compared with the corresponding lowland types. Much would be learned, however, by examining alpine Gramineae from other parts of the world, and especially other genera and species than those described in the preceding pages. Also the study of alpine types ought not to be restricted to a mere consideration of the foliar organs, even if these unquestionably are the most important; the structure © stem and root ought not to be excluded altogether, as is frequently oF nearly always the case. Conclusions We have seen that the alpine Gramineae of Colorado aril 2 an assemblage of very distinct geographical types; some that are onty 7 mpt. 15 BONNIER, Gaston, Cultures expérimentales dans les hautes altitudes. é re Rend. Acad. Sci. 1890; Etude expérimentale sur l’influence du climat alpin végétation et les fonctions des plantes. Bull. Soc. Bot. France 1888 : 436- *© WAGNER, Zur Kenntniss des Blattbaues der Alpenpflanzen = biologischer Bedeutung. Sitgungsber. K. Akad. Wiss. Wien 101:59- 189? 1908] HOLM—ALPINE GRAMINEAE 443 known from the alpine regions of this country; others that are known also from the higher mountains of Eurasia;. some that have reached the polar regions, among which several are circumpolar; and finally some that occur also at lower altitudes in these same mountains. The alpine genera seem to be more cosmopolitan than those observed at lower levels; as a matter of fact none of these genera of Gramineae are endemic to this country, and none of the alpine genera of Europe and Asia are endemic to those countries. The habit and floral structures of the alpine Gramineae of Colo- tado are remarkably uniform and simple, when compared with some of the other species and genera from the lowlands. Corresponding with this uniformity in habit, we meet with no extraordinary devel- opment of any of the tissues. The anatomical structure is rather simple, and neither the stereome, nor the chlorenchyma, nor the stomata exhibit any feature that might be looked upon as character- istic of an alpine type. In this respect the alpine Gramineae differ from most of the other families, not so much, however, from the Cyperaceae as from the Juncaceae (Luzula and Juncus), and especially from the dicotyledons. The habit and internal structure of the alpine dicotyledons of Colorado are very distinct from those of their representatives which thrive at lower elevations in mountains or on the plains and prairies; very prominent distinctions of this kind I have observed in a number of alpine genera, as Ranunculus, Trifolium, Claytonia, Stellaria, Synthyris, Mertensia, Primula, etc. Whatever conclusions may be drawn from the various treatments of alpine plants in general, and especially in regard to “adaptations,” it must e borne in mind that the monocotyledons have so far been almost entirely ignored, although they are certainly of no small interest on account of their frequent occurrence and very wide distribution in the high alpine regions. It seems thus very unsafe to describe the alpine leaf “in general” without including the Gramineae, and for this purpose the present paper may be of some interest to future students of ‘alpine structures.” BROOKLAND, D. C. EXPLANATION OF PLATE XXX. Fic. 1.—Cross-section of root stele of Poa Lettermanni: End, endodermis; P, pericambium; PL, proto-leptome; PH, proto-hadrome. X 560. 444 BOTANICAL GAZETTE [DECEMBER Fic. 2.—Root stele of Agrostis canina var.; letters as above. 560. Fic. 3.—Root stele of Festuca ovina; letters as above. 560. Fic. 4.—Root stele of Poa flexuosa; letters as above. 560. Fic. 5.—Part of root stele of Agropyrum Scribneri; letters as above. 560. Fic. 6.—Cross-section of part of culm of Poa Lettermanni, showing epider- mis (Ep), cortex he arene (St), and two mestome strands with their mestome sheaths (MS). X 1G. 7 sea é Spates: cross-section of leaf, ee: ventral epidermis (Ep) with a stoma, and two strata of chlorenchyma (C). X Fic. 8.—Same species; cross-section of leaf, Stovig dorsal ‘epidermis (Ep), hypodermal stereome (S#), and chlorenchyma (Ca). X 9 BOTANICAL GAZETTE, XLVI PLATE XXX IS > SO © C5 HOLM on ALPINE GRAMINEAE THE NATURE OF THE EMBRYO SAC OF PEPEROMIA:® WILLIAM H. BROWN (WITH PLATES XXXI-XXXIII) At the suggestion of Professor Duncan S. JoHNson, I undertook the cytological study of the development of the embryo sac of several species of Peperomia, with the purpose of finding out whether the development of this genus offered any support to the idea, recently advanced by several investigators, that when a row of megaspores is not formed, each of the first four nuclei of the embryo sac is to be regarded as a megaspore nucleus. The results found were exceptional and may be of interest, as they seem to throw some light on this question and also on the nature of the embryo sac of Peperomia. For the investigation, Professor JOHNSON turned over to me mate- rial of three species which he had collected for this purpose. Mate- tial of P. arifolia was collected in the greenhouses in Baltimore. The material was fixed in chrom-acetic or Fleming’s solutions. The sections were cut 10 # thick and stained with Fleming’s triple or Haidenhain’s iron-alum hematoxylin. The latter stain was used alone or counterstained with gentian-violet or eosin. This paper does not pretend to be a study of the whole life-history of Peperomia, but deals in detail only with the development of the » embryo sac. It is hoped, however, that this will throw some light on the origin of the peculiarities which have been described in its later development. The sixteen-nucleate embryo sac of Peperomia was discovered in Peperomia pellucida by CAMPBELL (’99), who, however, misinterpreted some of its features. JOHNSON (’00) describes the mature sac of P. pellucida as containing one egg, one cell with the position of a syner- gid, six nuclei which are cut off singly against the wall of the sac and finally degenerate, and eight which fuse to form the endosperm nucleus. The archesporium consists of a single hypodermal cell which cuts off a single parietal cell and then forms the embryo sac. In a later t Contribution from the Botanical Laboratory of The Johns Hopkins University, O08, 445] [Botanical Gazette, vol. 46 446 BOTANICAL GAZETTE [DECEMBER paper CAMPBELL (’oI) agrees with this description, except that he does not think that there is always in the mature sac a single cell which has the position of a synergid. That chromosome reduction takes place in the first division of the embryo sac nucleus was indicated by the presence of synapsis before this division in P. hispidula, as reported by JoHNSON before the Botanical Society of America at New Orleans in 1905. CAMPBELL (’or) thinks that the embryo sac of Peperomia is a primitive one, while JouNnson (?00) considers its peculiar structure as derived. In this paper it will be shown that the embryo sac is made up of the descendants of four nuclei which are apparently the nuclei of four megaspores, and that these nuclei have, by the loss of dividing walls, come to lie in the same cell. Some of the peculiar features of the mature sac are probably connected with this fact. For the sake of convenience, each of the four species will be described separately, after which the general considerations will be discussed. Peperomia Sintensii The material of this species was collected in Jamaica by Mr. W. R. Maxon and identified by M. Casimir DE CANDOLLE. The development of the flower and of the mother cell in the nucel- lus agrees with that described for P. pellucida by JOHNSON (’00). The flower consists of two stamens and a carpel in the axil of the bract. The ovule (fig. 28) is single and orthotropus, with a single integument (fig. 28, i), which makes its appearance about the time that the tape tum is cut off from the archesporium (jig. 2). : The archesporium arises in the apex of the nucellus as a Sin hypodermal cell (fig. 1), which is clearly distinguished from sade rounding cells by its larger size and more densely staining conten - At the micropylar end this cuts off a single parietal cell (fig. 2), am then, without giving rise to any other cells, forms the embry? ni The parietal cell divides first by an anticlinal wall and then by repeat divisions gives rise to a mass of tissue between the embryo sac a? micropyle (figs. 4, 28, t). the Owing to the scarcity of young material, I was unable to — i chromosomes in the division cutting off the tapetum, but : tapetum and in the nucellus there were regularly about sixteen on, gle 1908] BROW N—PEPEROMIA 447 mosomes. This is double the number found in the embryo sac, as will be described later. The chromosomes are small and short, and are therefore readily counted in a cross-section of a spindle at meta- phase. Fig. 2 shows such a section in the tapetum, while fig. 3 represents a longitudinal view of a vegetative nucleus at a slightly older stage. Up to this time there certainly seems to have been no chromosome reduction, and nothing resembling megaspore forma- tion. : The single sporogenous cell (fig. 2) which is left after the cutting- off of the tapetum and which is to form the embryo sac is apparently a megaspore mother cell, as will be shown below. Its nucleus divides to two, four, eight, and finally in the mature sac to sixteen nuclei. The first division is heterotypic and takes place as follows. The resting nucleus (fig. 4) shows a meshwork of linin along which chro- matin granules are scattered. In the center of this meshwork is a large clear space containing a large nucleolus. After considerable growth the nucleus goes into synapsis. The meshwork contracts rapidly around, or to one side of, or even at some distance from, the nucleolus, into a mass in which very little detail can be made out. Fig. 5 represents an early stage of synapsis, while fig. 6 is probably older. No evidence of a fusion of spirems was seen either before or during the early stages of synapsis. At the end of synapsis the mass loosens up, and later appears in the form of a spirem, along which single granules are scattered at rather regular intervals (fig. 7). The spirem is apparently continuous and becomes loosely coiled, and the granules divide along the longi- tudinal axis of the spirem. A small portion of such a stage is shown in fig. 8. After this the spirem divides longitudinally and the two halves may diverge considerably in places (fig. 9), but later they come together again and all apparent traces of the division are lost. While this is taking place, the spirem is beginning to be arranged in loops (fig. 10), and is still apparently continuous, the loops being rounded at the ends. It does not seem possible that this appearance can have anything to do with the splitting just described. The looping be- comes more pronounced and the spirem segments transversely in such a way that.the loops give rise to chromosomes. There are eight of these, the haploid number, and they are apparently formed by the 448 BOTANICAL GAZETTE [DECEMBER coming together side by side of parts of the spirem that before were arranged end to end. “The chromosomes then contract and show the twisted appearance characteristic of the heterotypic division (fig. 11). After considerable contraction they have the appearance of two irregular rounded masses lying together. Sometimes these are seen to be connected by strands (fig. 13), and just before this, when the constituent halves are about twice as long as wide, they are sometimes placed end to end with a constriction between them (jig. 12). It would seem from this that the two halves originally placed end to end in the spirem, then side by side in the loops, again come to lie end to end, and that each half probably represents a chromosome (cf. fig. 16). The strands connecting the two halves are often seen to be double (figs. 12, 13), and they might always be so if seen in the right plane. Besides this, the halves sometimes show evidence of being double. This may be due, as is often supposed, to the split previously described. Before the spindle is formed the two halves come together, producing somewhat elongated chromosomes (fig: 7 4). About this time the nucleolus begins to fragment and to be thrown out into the cytoplasm. After the spindle is formed (fig. 15) the chromo- somes divide transversely to their long axes (fig. 16). From what has been said it seems evident that this division separates parts of the spirem which were originally placed end to end and that it is there- fore a transverse division. This is then the heterotypic and reducing division. . As the chromosomes approach the poles they become crowded together (fig. 17) and surrounded by a clear space. While this 15 going on, the chromosomes lose their distinct outlines and a nucleolus makes its appearance in their midst. While the chromosomes lose their distinct outline and probably also some of their substance, they seem nevertheless to be represented by irregular masses during most if not all of the period between the first and second divisions (figs: 18-20). Between the succeeding divisions they seem to go to ~ to a much greater extent (cf. figs. 22-25). Before the formation ¢ = spindle, the chromosomes appear as double structures, consisting two rods lying side by side. It may be that these represent i two halves of the spirem seen in the prophases of the first — 1908] BROWN—PEPEROMIA 449 and that the second division completes the longitudinal separation begun in the first. The first two divisions differ from those in P. pellucida in that there are formed evanescent walls separating the daughter nuclei. When the daughter nuclei of the first division have begun to be organized, an equatorial plate is formed on the spindle (fig. 17). This grows until it becomes a wall stretching across the embryo sac (jig. 18). The plane of this wall is not constant, but it may extend longitudinally or transversely across the sac, or take any intermediate position, and may also separate the sac into equal or unequal parts (figs. 18-20). It persists only for a short time, disappearing before the next division or remaining as a remnant after it (fig. 21). There is no trace of it _ later in the four-nucleate stage. When the two nuclei divide to four, plates are formed on both spindles. One of these never becomes very prominent, but the other forms a wall separating one nucleus from the other three (fig. 22). The position of this wall is variable, as was the one in the two-nucleate stage. It may cut off a nucleus at either end or any side of the sac, but generally it appears at the lower end. This wall, like the first, persists for only a short time. It generally disappears before the next division (fig. 23), but may per- sist as a remnant after it. As in P. pellucida, the four nuclei assume the position of the nuclei of a tetrad of microspores. The walls just described are apparently megaspore walls. This, however, will be discussed later. In the next two divisions all of the nuclei divide simultaneously, giving eight, and then in the mature sac sixteen nuclei. The nuclei of the eight-nucleate stage and of the mature sac are arranged about the periphery of the sac (figs. 24-28). As in P. pellucida (JOHNSON 00), one of the sixteen nuclei becomes an egg, another has the position of a synergid, six are cut off singly against the wall and finally degen- erate, while eight fuse to form the endosperm nucleus. Fig. 29 shows a sac in which fertilization is taking place. Four of the peripheral nuclei are shown, while five others are fusing to form the endosperm nucleus. One of these latter was probably formed by the fusion of two. The other two fusing nuclei, as well as two peripherals, are in another section. In the division of the four nuclei to eight no colt plates are formed. 450 BOTANICAL GAZETTE [DECEMBER Fig. 24 represents a stage in which they should be apparent if present. In the last division (fig. 26), cell plates are formed on all the spindles. These give rise to walls cutting off all of the nuclei except those which are to fuse to form the endosperm nucleus, but leaving these eight free in the cytoplasm (figs. 27, 28). These walls are thin at first and might be easily overlooked, but later they become much more prominent. In the eight-nucleate stage two nuclei are always found together at the micropylar end (jig. 25). The presence of spindles show these to be sisters (fig. 24). In the last division one of these gives rise to the egg, the other to the nucleus with the position of a synergid (figs. 26-29). The sisters of the egg and synergid fuse with the sisters of the six peripherals to form the endosperm nucleus. As in P. pellucida (JOHNSON ’00) the peripherals are arranged singly against the embryo sac wall (jig. 29) and finally degenerate. About the time of fertiliza- tion the eight nuclei which form the endosperm nucleus migrate toward the base of the sac and fuse into one large nucleus. STRASBURGER (05) assumes that owing to their position the polar nuclei in the ordinary angiosperm are not surrounded by cell walls and that their fusion is due to the fact that their development has stopped and that they are in a single cell. This explanation may apply to the eight fusing nuclei in P. Sintensii. A peculiar phenomenon was noted in fertilization. The male and female nuclei at this time are in the resting stage and have one of more cavities with their concave sides facing each other (fig. 29): The edges fuse so that a mass of cytoplasm is apparently held in the fusion nucleus (fig. 30). The wall around this mass of cytoplasm grows faint and finally disappears. : The mature seed resembles that of P. pellucida (JOHNSON 00). There is a small oval embryo, while the rest of the sac is filled with a much larger endosperm, which is cellular from the first division. The sac is about the same size as at fertilization, but the cells of the nucellus have become filled with starch to form perisperm. Peperomia arifolia The development of P. arifolia was followed only as far as the sixteen-nucleate sac. pak The development of the flower and of the embryo sac agrees T°" 1908] BROWN—PEPEROMIA 451 closely with that just described for P. Sintensii. There is a single archesporial cell which cuts off a tapetal cell and then forms the embryo sac. The tapetum divides as in P. Sintensii. The embryo sac nucleus divides to two, four, eight, and finally sixteen nuclei. The first division is heterotypic and shows the usual synapsis. At this division a cell wall is formed across the sac. This wall is variable in position and generally disappears before the next division, but may persist as a remnant after it. At the second division plates. are formed on both spindles. One soon disappears, while the other forms a wall separating one nucleus from the other three. This wall is variable in position, and all signs of it are usually lost before the next division. The next two divisions leave the mature sac with sixteen nuclei. Peperomia ottoniana ~ The material of this species was collected in Mexico by Dr. CF: CHAMBERLAIN. It is very much like P. Sintensii, but shows some constant differences. It was identified by M. Castmir DE CANDOLLE. Owing to lack of young material the investigation of this species had to be begun with the four-nucleate stage. There were only three ovules showing a four-nucleate sac, but they are worth recording, as they appear perfectly normal, and seem to throw some light on the problem under discussion. The youngest sac (fig. 31) shows the micropylar nucleus com- pletely cut off from the other three by a very distinct and well-devel- oped wall. This nucleus is much larger than the other three, which are all about the same size. The cell occupied by this large nucleus contains much denser protoplasm than the one containing the other three. The stage just described resembles rather closely the four megaspores of the ordinary angiosperm, where one megaspore is to form the sac while the other three degenerate. |The further develop- ment, however, seems to be different, and agrees with the two species of Peperomia just described. The two other four-nucleate sacs which were seen are larger and apparently older than the one just described, and show no sign of a wall separating the nuclei, which are all about the same size (fig. 32). The eight nuclei formed from these four show no appreciable differ- ence in size. 452 BOTANICAL GAZETTE [DECEMBER The further development resembles very closely that of P. Sin- tensit. ‘The mature sac contains sixteen nuclei. There is one egg and one nucleus with the position of a synergid. Six peripheral nuclei are cut off against the wall of the sac. The remaining eight fuse to form the endosperm nucleus about the time that fertilization takes place. In the fusion of male and female nuclei there was seen no sign of protoplasm being taken into the nucleus, as described for P. Sintensii. Many of the stages of this species resemble P. Sin- tensit so closely that one might readily be mistaken for the other. Peperomia pellucida The development of the embryo sac nucleus and the structure of the mature sac, as described by JoHNSON, agree with the description just given for P. Sintensii. Therefore only the first two divisions of the embryo sac nucleus need be considered here. The first division is heterotypic and shows about ten or twelve chromosomes. A meshwork contracts and goes into synapsis. This stage is followed by an apparently continuous spirem, which divides into twisted heterotypic chromosomes. In both divisions plates are formed on the spindles. These plates probably do not develop further, as no larger plates or walls were seem, although a great number of nuclei were examined at stages which should show them if present. These plates probably are the reat nants of walls such as have been described for the other three specie Discussion As has been said, CAMPBELL (’or) considers the unusual structure of the embryo sac of Peperomia as primitive, and expresses the belief “that the contents of the embryo sac with the sixteen nuclei represent a prothallial tissue and the nuclei are at first entirely similar.” Jom SON (02), after a study of Peperomia and allied genera, comes t? the conclusion that the peculiarities of the embryo sac have been secon’ arily acquired from the ordinary angiosperm embryo sac. ae The present investigation seems to support the latter view. * ~ nuclei of the mature sac of P. Sintensii, instead of being § di first, bear a definite relation to each other. The presence - : reducing division in the primary embryo sac nucleus and the forme 1908] BROWN—PEPEROMIA 453 tion of evanescent walls in the first and second divisions seem to indi- cate that the sac is composed of the descendants of the nuclei of four megaspores and that the primary embryo sac nucleus is a mother cell and not a megaspore nucleus. If the walls corresponded to those of prothallial cells, we should expect to find them in the third division, but here not even a cell plate was seen. Besides this, the nearest phylogenetic relatives in which the first divisions of a megaspore result in a cellular structure are found among the leptosporangiate Filicales, where the heterospory is supposed to be of rather late origin, and it does not seem probable that Peperomia has reverted to the characters of an ancestor as remote as one in which we would find the first divisions of the megaspore giving rise to a cellular structure. This position is strengthened when we consider the four-nucleate stage of the Mexican species. Here the nucleus which is cut off is considerably larger and surrounded by much denser protoplasm than the other three. The resemblance to the four megaspores of the ordinary angiosperm is quite striking. The presence of the extra nuclei in the mature sac is in harmony with the view that these nuclei are the descendants of four megaspore nuclei. The nuclei of the four-nucleate sac of Peperomia have the same position with reference to each other as the nuclei of a tetrad of fern spores or of a tetrad of microspores of a spermatophyte. This posi- tion is not always apparent when the nuclei are dividing, and as the sac is somewhat rounded it may be that this arrangement is a mechan- ical response to the physiological conditions. That four potential megaspore nuclei may be included in a single cell has been shown by CANNON (’00) for Avena fatua. Here the four megaspore nuclei may or may not be separated by cell walls, but in either case three degenerate and the other forms the embryo sac. A similar phenomenon is reported by SmrrH (’98) for Eichhornia. The case of Crucianella (LLoyp 702) is interesting in this con- nection. Here the four megaspores are not separated by walls, but indications of plates are found on the spindles in the divisions of the megaspore mother cell nucleus. According to Lioyp, the four Megaspores are physiologically and morphologically similar. Each 454 BOTANICAL GAZETTE [DECEMBER nucleus divides to two, but afterward the nuclei derived from the three megaspores nearest the chalazal end degenerate, while those from the one nearest the micropyle form the sac. The condition in Crucianella approaches that in Peperomia, and it may be that the shape of the sac, which is much less elongated in Peperomia than in Crucianella, gives the megaspores a better chance to develop together in Peperomia. That physiological conditions do play a part in the structure of the embryo sac of Peperomia may be indicated by the fact that while the megaspore nucleus which is cut off by a cell wall is generally at the chalazal end, it is always the one nearest the micropyle which forms the functional egg apparatus. WrEcGAND (’00) reports an evanescent wall in the first division of the embryo sac of Convallaria. Here the mother cell forms the embryo sac directly and this wall may represent a megaspore wall. That more than one megaspore may possess the potentialities for development is indicated by the number of plants in which more than one has been reported as dividing (CouLTER and CHAMBERLAIN 703). The similarity in the fate of the four megaspores of P. Sintensii is striking. Each gives rise to two nuclei of the endosperm and two cut off against the embryo sac wall. : If we were to accept the view of Porscx (’07) that an egg 4pPat atus represents an archegonium, we might conceive of the em id bd sac of Peperomia as really composed of four sacs, each of which gives rise to a single archegonium. © The relationship of the nuclei of each egg apparatus, as previously described, is the same as that found in the egg apparatus of an ordinary angiosperm, if we assume that one synergid fuses with the nucleus which usually fuses to form the endo- sperm, that is, with the sister of the egg, as is the case in the foe nucleate sac of Cypripedium (Pace ’08). That there may sch Peperomia four potential egg apparatuses is indicated by the fact that the nucleus of the four-nucleate stage, which is cut off and there- fore resembles the functional megaspore of the ordinary angiosperms does not usually form the functional egg apparatus. It must be remembered, however, that no such. similarity in the fate of the meg spore nuclei as has been described for P. Sindensii exists in P. MS 1908] BROWN—PEPEROMIA 455 pidula (JOHNSON ’07), where fourteen out of sixteen nuclei fuse to form the endosperm nucleus. Before applying the theory of PorscH it may be well to consider the theory itself in its relation to the ordinary gymnosperms and angiosperms. In Selaginella, Isoetes, and the gymnosperms, all of the first divisions of the megaspore are non-cellular, after which there is a number of cellular divisions in all species that form archegonia. It is in the cellular tissue that the archegonia are formed by cell divisions. The first two divisions of the ordinary angiosperm embryo sac are generally homologized with the free nuclear divisions of the gymnosperm prothallus, and the fact that in the derived sac of P. Sintensii, where cell walls are formed at the first two or megaspore- forming divisions, there is no sign of even a cell plate at the third or prothallial division, indicates that the character of the free cell divisions in the angiosperms is quite constant. It does not seem probable that nuclei formed in the angiosperm embryo sac by free nuclear division can be homologous with the nuclei in the cellular archegonia of the gymnosperms, for we would have to explain how the archegonia became shifted back from the cellular to the non- cellular phase of the prothallus. If the above idea is correct, the polar groups in the angiosperm embryo sac can have no such phylogenetic significance as is ascribed to them by Porscu, but all of the nuclei in the mature sac must be homologous or at least differentiated only in the last division. From what has been said, it seems possible that in some angio- sperms besides Peperomia, in which the embryo sac is not developed from one of a row of megaspores, the first four nuclei of the sac are megaspore nuclei. It must be remembered, however, that in most Cases we have no evidence for this, other than the presence of the reducing division in the embryo sac mother cell, and it is a mistake to suppose that the same structure may not come about in plants in more than one way. Besides this, it is hard to see how four embryo sacs can have become merged into one in the large number of cases in which a row of megaspores is not formed (CouLTER and CHAMBER- LAIN ’03) without disturbing the normal number and position of the nuclei, as has been done in Peperomia. Some workers have been inclined to regard the presence of the 456 BOTANICAL GAZETTE [DECEMBER heterotypic division in a cell of the nucellus as the sole criterion for determining that this cell is a megaspore mother cell, and that the first four resulting nuclei are the nuclei of megaspores. This view seems to leave out of consideration the great number of points in the life-history of plants at which reduction may take place, and the evident tendency among vascular plants toward the reduction of sporogenous tissue in the megasporangium and nucellus. In the Archegoniatae the archesporial cell may give rise to a large mass of tapetum and a considerable number of functional spore mother cells. Since we can trace the reduction of these divisions until among angiosperms the archesporial cell may without dividing form one megaspore mother cell, it does not seem reasonable to sup- pose that the divisions of the mother cell to four megaspores may not also be left out and the mother cell function directly as a megaspore. In this case the heterotypic division might be pushed forward and take place in the embryo sac. Among the lower plants this reducing division may take place at almost any point in the life-history and there seems to be no sufficient reason for thinking that it must occur at the same place in all angio sperms. If the two divisions which form the spores from the mother cell, or one of them, have been left out, we could of course expect to find no evidence of it other than the entire absence of any signs of the division. In a recent paper on Cypripedium, Miss Pace (’08) shows that the sporogenous cell divides once and one of the resulting cells forms the embryo sac, while the other may occasionally divide once. There is not even a sign of a cell plate in the first division of the nucleus which forms the embryo sac. Miss PAce calls the first two nuclel of the embryo sac megaspores, but does not state her reasons for doing so. The question might arise as to whether they are megaspores or whether one division in spore formation has been left out. That the nucleus of the degenerating cell should occasionally divide does not seem surprising when we remember the large number of plants » which the nucleus of a degenerating megaspore may do so. The writer does not wish to be understood as denying that pe are two megaspores in the embryo sac of Cypripedium, oF that 1908] BROWN—PEPEROMIA 457 first four nuclei in the embryo sac of any plant in which a row of megaspores is not formed are megaspore nuclei, but simply as sug- gesting that in most cases we have no adequate proof of this, and that in the present state of our knowledge there is at least one other way in which some of them may be regarded. The homologies in all these cases may be cleared up by further work. We have, however, no right to push them further than the present evidence justifies, or to suppose that all plants must behave alike in this respect, when we consider the large number of different analogous organs which have been arrived at by very diverse methods. Summary The archesporium of the species of Peperomia studied arises as a single hypodermal cell, which cuts off a single parietal cell and then forms the embryo sac directly. The first division of the embryo sac nucleus is heterotypic. The nucleus goes into synapsis. This stage is followed by an apparently continuous spirem. This splits longitudinally but later the two halves come together again. The chromosomes are formed from loops in the spirem. When these divide, they seem to separate two parts of the spirem which were originally placed end to end. The second division may divide the chromosomes along the longitudinal split seen in the prophase of the first division. In the third division of the embryo sac nucleus of P. Sintensii, no cell plates were seen on the spindles, but in the last division cell walls are formed on all the spindles. These walls cut off, against the embryo sac walls, one of each of the eight pairs of nuclei, and leave the other eight free in the cytoplasm. These free nuclei fuse to form the endosperm nucleus. The egg and a nucleus with the position of a synergid are cousins. The other six nuclei which are cut off against the embryo sac wall finally degenerate. The mature sac contains sixteen-nuclei, which are apparently derived from four megaspores. That the first four nuclei of the embryo sac are megaspore nuclei is indicated by the fact that the first division of the embryo sac mother cell nucleus is heterotypic and reducing, and that in P. pellucida cell plates are formed on the Spindles of the first two divisions, while in P. Sintensii. and P. 458 BOTANICAL GAZETTE [DECEMBER arifolia these plates grow into evanescent walls which extend across the embryo sac and separate the nuclei. We are not justified, however, in extending the conception of four megaspores in an embryo sac to all angiosperms in which a row of megaspores is not formed, because we do not know that the division of the mother cell to megaspores may not be omitted and the place of the heterotypic division be changed. In the fertilization of P. Sintensii some cytoplasm appears to be taken into the nucleus. Nore.—Since the above was written, there have appeared two papers dealing with sixteen-nucleate embryo sacs. One is by COUL- TER,' in which he expands a suggestion offered by Lioyp in 1902, that when four megaspores are not formed the first four nuclei of the sac are spore nuclei so far as development is concerned, and says that the formation of megaspore nuclei cannot be omitted. In a paper on the phylogeny of the angiosperm embryo sac, ERNST’ describes a sixteen-nucleate embryo sac in Gunnera. Here he finds an egg, two synergids, six antipodals often in two groups of three, and seven nuclei which fuse to form the endosperm nucleus. He then attempts to fit the archegonial theory of PorscH to Gunnera, and concludes that the egg group represents an archegonium, while two more are represented by the six antipodals together with two of the nuclei which fuse to form the endosperm. He thinks that the other four nuclei fail to form an archegonium, and that the explana- tion which he gives of the embryo sac of Gunnera may apply m Peperomia pellucida. In the case of the embryo sac of P. Simiens™, which resembles very closely that of P. pellucida, it has already been shown that if we should apply the theory of Porsc# there would be four and not three archegonia. Ernst has not worked out the rela- tion between the nuclei in the embryo sac of Gunnera, and therefore it would seem premature to speculate as to the conditions there, but there seems to me to be no sufficient reason for thinking that the nuclel would represent three rather than four of the archegonia of PorscH. Jouns Hopkins UNIversity BALTIMORE * CouLTER, J. M., Relation of megaspores to embryo sacs in angiosperms: GAZETTE 45: 361-366. 1908. ___ 2 Ernst, A., Zur’ Phylogenie des Embryosackes der Angiospermen- Deutsch. Bot. Gesells. 26: 419-437. pl. 7. 1908. Bot. Ber- 1908] BROW N—PEPEROMIA 459 LITERATURE CITED 1. CAMPBELL, D. H., Die Entwicklung des Embryosackes von Peperomia pellucida Knuth. Ber. Deutsch. Bot. Gesells. 1'7:452-456. pl. 31. 1899. , A peculiar embryo sac in Peperomia pellucida. Annals of Botany 13:626. 1899. : . Cannon, W. A., A morphological study of the flower and embryo of the wild oat, Avena fatua. Proc. Calif. Acad. Sci. III. 1: 329-364. pls. 49-53. 1900. 4. COULTER AND CHAMBERLAIN, Morphology of angiosperms 76-80, 84-86. ad w 1903. 5. Jonnson, D. S., On the endosperm and embryo of Peperomia pellucida. Bor. GAZETTE 30:1-11. pl. 1. 1900. , On the development of certain Piperaceae. Bot. GAZETTE 34:321- 340. pls. 9, 10. 1902. . ——, A new type of embryo sac in Peperomia. Johns Hopkins Univer- sity Circular 195:19-21. pls. 5, 6. 1907. 8. Lioyp, F. E., The comparative embryology of the Rubiaceae. Mem. Torr. Bot. Club 8:27-112. pls. 8-15. 1902. 9. Pace, Luta, Fertilization in Cypripedium. Bot. GAZETTE 44:353-374 pls. 24-27. 1908. 10. Porscu, Orro, Versuch einer phylogenetischen Erklarung des Embryo- sackes und der doppelten Befruchtung der Angiospermen. 1907 11. SuirH, R. W., A contribution to the life-history of the Pontederiaceae. Bor. GAZETTE 25: 324-337. pls. 19, 20. 1908. 12. STRASBURGER, E., Die Samenlage von Drimys Winteri und die Endosperm- bildung bei Angiospermen. Flora 95:215-231. 1905- 13. Wriecanp, K. M., The development of the embryo sac in some monocoty- ledonous plants. Bot. GAZETTE 30:25-47. pls. 6, 7. 1900. a EXPLANATION OF PLATES XXXI-XXXII All drawings were drawn’ with the aid of a camera lucida and reduced one- half. Figs. 1, 2, 4, 18-23, 31, 32 were made with a no. 8 ocular and a 2.6°= objective; figs. 3, 5-17 with a no. 12 ocular and a 1.5"™ objective; (figs. 24- 27, 29, 30 with a no. 8 ocular and a 7x objective; jig. 28 with a no. 2 ocular and a } objective. Peperomia Sintensit Fic. 1.—Primary archesporial cell in apex of nucellus. Fic. 2,—Archesporial cell has divided to sporogenous and parietal cell; the latter dividing and showing sixteen chromosomes, integument beginning to grow up around nucellus. Fic. 3.—Longitudinal view of an anaphase in a vegetative cell. Fic. 4.—Nucellus containing embryo sac mother cell, which shows a stage shortly before synapsis; part of integument which now surrounds nucellus shown at base of nucellus. 460 BOTANICAL GAZETTE [DECEMBER Fic. 5.—Early stage of synapsis in embryo sac mother cell. Fic. 6.—Later stage of same. Fic. 7.—Part of an apparently continuous spirem, just after synapsis. Fic. 8.—Later stage of same, showing divided granules. Fic. 9.—Still later stage, showing split spirem. Fic. 10.—Still later stage; the two halves have come together and the spirem has become looped. Fic. 11.—Chromosomes derived from loops shown in jig. 10. Fic. 12.—Later stage of same. Fic. 13.—Still later stage. Fic. 14.—Still later stage; the two halves have come together. Fic. 15.—Longitudinal section of a metaphase of the first division of embryo sac mother cell. Ic. 16.—Anaphase of same. Fic. 17.—Early stage in formation of daughter nuclei. Fic. 18—Two-nucleate embryo sac, showing cross-wall separating the two nuclei. : Fic. 19.—Slightly older embryo sac. Fic. 20.—Embryo sac showing same stage as last. Fic. 21.—Nuclei of a two-nucleate sac dividing; remnant of dividing wall still present. Fic. 22.—Four-nucleate sac ; one nucleus separated from the other three by a wall. Fic. 23.—Later stage; wall was disappeared. Fic. 24.—Four nuclei have divided to eight; no cell plates on the spindles; the sister nuclei in micropylar end. Fic. 25.—Later Stage; the two sister nuclei still in micropylar end. Fic. 26.—The eight nuclei have just divided to sixteen; cell plates seen on the spindles. Fic. 27.—Later Stage; cell plates shown in last figure have grown into walls cutting off eight nuclei against the embryo sac wall and leaving eight free in me cytoplasm. Fic. 28.—A mature ovule; the embryo sac contains sixteen nuclei; , pollen tube with nuclei; ¢, tapetum; 7, in ent. Fic. 29.—Embryo sac with fertilized egg and nuclei fusing to form the wee Sperm nucleus; e, egg with fusing nuclei; 7, pollen tube; s, nucleus with : Position of a synergid; d, peripheral nuclei which will degenerate; f, nuclei fusing to form endosperm nucleus. Fic. 30.—Later stage of fusion in male and female nuclei. Peperomia ottoniana Fic. 31.—Four-nucleate sac; one nucleus cut off and surrounded by dense ; ae arse Fic. 32.—Later stage; the wall a: g ‘4 1 ~~ - PI MNIGAL GAZETTE, XIVI : PLATE XXXI FE i eg. snPLATE XXX IL 4NIGAL GAZETTE, XLVI MNICAL GAZETTE, XLVI ee BRIEFER ARTICLES A NEW POISONOUS MUSHROOM (WITH TWO FIGURES) During last August I received from Dr. O. E. FiscHER, Detroit, Michi- gan, a few living plants of a species of Tricholoma, which he reports as causing several severe cases of poisoning. The specimens were suff- ciently well-preserved for study and diagnosis, also for a photograph, and for casting spores for a photomicrograph. The plants are medium size, white in color with dull clay-colored tinge and stains in places. The plants are moist but not viscid, with the pileus minutely scaly but sub- tomentose over the center. The scales possess the darker color and under the hand lens some of them appear nearly black, but because of their minute size the dark color is not evident to the eye. The stems are sub- bulbous, the shape of the bulb being peculiar and resembling that of Lepiota lenticularis, which in side view is supposed to suggest the shape of a biconvex lens. The taste of the plants is mild, and no particular.odor was observed in those received. The plants appear to be near to T7ri- choloma pallidum Pk. from Worcester, Mass., but differ in a number of par- ticulars, as will be seen by a comparison of the diagnoses. Before giving the technical diagnosis I quote the following from Dr. FIscHER’s letter: I am sending you a set of agarics of unusual interest and importance, for they are the ones that made seven people very ill iri Rochester, Mich., on August 21. Violent and hemorrhagic vomiting, diarrhoea, sweating, and some cardiac dis- turbance were the symptoms, lasting several hours and coming on one hour after eating even of minute quantities. Some of the women are still suffering from intestinal disturbance. None that ate escaped; none died. I have spent con- siderable time and energy in taking two of the victims to the exact spot where they picked the offenders and got the cause of the trouble. It is a white- spored agaric, growing in open grassy woods on a leafy base, in clusters ~ - groups. I should greatly appreciate a certain identification of this agaric, the mo * So since it looks, tastes, and smells inviting, and was ‘‘O.K.’d” by a member of our - club. Tricholoma venenatum Atkinson, n. sp.—Plants 4-8°™ high, pileus 4-7°™ broad, stem 1-1.5°™ thick, plants white with dull clay-colored tinge and stains; pileus moist not viscid, convex-expanded, subumbonate, 461] [Botanical Gazette, vol. 46 462 BOTANICAL GAZETTE [DECEMBER center fleshy, thin toward the margin, plane or subrepand, minutely scaly with fibrous scales, subtomentose area over center, surface pale buff a a 2 aS a4 rs < ~Tricholoma venenatum I. Fic. to pale clay color, the scales possessing the darker color, under the lens some of them appear nearly black; gills adnexed, broadly sinuate, sub- 1908] BRIEFER ARTICLES 403 distant, whitish, thin, dull clay color especially where bruised; spores white, smooth, oval to broadly subelliptical, 5-7 X3 .5-5 #; cystidia none; stems subbulbous with a bulb like that of Lepiota lenticularis, fibrous id, sordid white, becoming in age where handled dull clay color; — striate, so Fic. 2.—Photomicrograph of spores of Tricholoma venenatum; Zeiss ocular No. 18, objective 3™™; object 370™™ from sensitive plate. odor and taste mild.—No. 22573 C. U. Herb., from Dr. O. E. FISCHER, Detroit, Mich., received August 29, 1908. (Sporophoro albo, leniter sordide luteo, 4-8°™ longo, pileo 4-7°™ lato, stipite I-1.5°™ crasso; pileo convexo-expanso, subumbonato, squamulis minutis ob- ducto; lamellis adnexis, late sinuatis, tactu sordide luteis; sporis hyalinis, glabris, Ovatis vel subellipsoideis, 5-7 3-5-5 #5 stipite subbulbo, fibroso-striato, tactu sordide luteo.) Gro. F. Atkinson, Department oj Botany, Cornell University. 464 BOTANICAL GAZETTE [DECEMBER AFFINITIES OF PHYLLOCLADUS CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 121 In connection with the work on Phyllocladus alpinus published in this journal (Bot. GAzETTE 46:339-348. pls. 20-22. 1908), it was the inten- tion not to venture upon a discussion of the relationships until a more complete knowledge of the life-history had been obtained from further material. On account of the probable delay connected with securing and investigating the new material, it seems better to present at this time such conclusions as the results already obtained seem to justify. In 1872 Phyllocladus was placed among the Podocarpineae by STRAS- BURGER," the relationship being based upon external resemblances. In ENGLER and Prantt’s Pflanzenfamilien it is put among the Taxineae. In 1903 Prtcer? placed it in a separate group (Phyllocladoideae) inter- mediate between Taxineae and Podocarpineae; this disposition of the genus being based upon features in which Phyllocladus differs from the Taxineae, namely the two-sporangiate microsporophyll, the uniovulate scale, the arillus, and the anatomy of the vegetative structures. Miss RosBErtsons follows PILGER in assigning to Phyllocladus this intermediate position, with a greater affinity for the Podocarpineae. In comparing Phyllocladus with the Podocarpineae and with the Taxineae, its relationship to the former tribe becomes very evident. The principal features of resemblance to Podocarpineae, in contrast with the corresponding features of Taxineae, may be enumerated as follows: 1. The microsporophyll of Phyllocladus bears two abaxial sporangia ; the microsporophylls of the Taxineae are all of the peltate type, bearing | three to eight sporangia. 2. Each scale of Phyllocladus bears one centrally placed ovule; among the ees each scale bears two lateral ovules. .. The microspores of Phyllocladus have wings, and four or five nuclei at ie time of shedding; those of the Taxineae have no wings, and only one or two nuclei at the time of shedding. 4. Male prothallial cells are formed in Phyllocladus and in all the Podocarpineae; none occur in the Taxineae. 5. The evanescent prothallial tissue of Phyllocladus is similar to that found in the Podocarpineae. 6. The megaspore membrane is well developed; this membrane is * STRASBURGER, E., Die Coniferen und die Gnetaceen. oo 2 Pircer, R. Tees Pflanzenreich, nos. 4, 5. I 3 Romrersox, AGNES, Some points in the as a Phyllocladus ae Annals of Botany 20:259-265. pls. 17, 18. 1906. 1908] BRIEFER ARTICLES 465 present in all the gymnosperms except the Taxineae, among which it is almost entirely eliminated.4 The features in which Phyllocladus resembles the Taxineae and differs from the Podocarpineae are as follows: . The ovule is erect; in the Podocarpineae it is more or less inverted, ae in Dacrydium latifolium. 2. The cladodes contain centripetal wood, according to Miss ROBERT- SON (/.¢.). WoORSDELLS states that centripetal wood is more common among the Taxineae than in any other group of Coniferales; it has been found in the leaf and cotyledon of Taxus and Cephalotaxus, in the cotyledon of Torreya,® and in the stem of Cephalotaxus koraiana.? 3. The arillus of Phyllocladus originates at the base of the ovule, just as does that of Taxus; the so-called epimatium (Pricer, /. ¢.) of Podo- Carpus arises from the scale. If this epimatium represents the arillus of Phyllocladus and Taxus, it differs in origin and form; if it does not repre- sent the arillus, it is a structure not found in those genera. These comparisons indicate that in number and in importance the features of Phyllocladus in common with those of Podocarpineae are much greater than those in common with Taxineae. The winged micro- Spores and the multicellular and evanescent prothallial tissue alone would seem to be of sufficient importance to associate Phyllocladus with the Podocarpineae. We are inclined, therefore, to assign Phyllocladus to the Podocarpineae, thus confirming STRASBURGER’s conclusion of 1872; and not to regard it as referable to Taxineae, or as worthy of consti- tuting a distinct group.—N. JoHANNA Kitpau., The University of Chicago. NOTE ON THE POLLEN OF MICROCACHRYS Norén® has recently described certain of the reproductive features of Saxegothaea. He found that the microspore, like that of the other podo- carps recently described, has supernumerary prothallial cells. Unlike the other forms, however, the grains are not winged. In connection with the 4 THomson, R. B., The megaspore membrane of the gymnosperms. Univ. Toronto Biol. Series, no. 4. 1905. 5 WorRSDELL, W. C., On transfusion tissue; its origin and function in the leaves of gymnospermous plants. Trans. Linn. Soc. Bot. London II. §:301-319. pls. 23-26. 6 ae EpiTH, The seedling of Torreya myristica. New Phytol. 2:83. 1903. OTHERT, W., Ueber parenchymatische Tracheiden und Harzgange im Mark ~ von Si aca s-Arten. Ber. Deutsch. Bot. Gesells. 17:275. 1899. 8 Norén, C. O., Zur Kenntnis der Entwicklung von Saxegothaea conspicua Lindl. Svensk. Bot. Tidskr. 2:101-122. pls. 7-9. 1908. 466 BOTANICAL GAZETTE [DECEMBER deposition of the pollen there is a very interesting condition. Sometimes the pollen falls in the micropyle, and sometimes in the cavity around the ovule, whence it grows over the tissues into the micropyle. This recalls the condition of affairs in the Araucarieae, and is essentially similar in this respect to Agathis, as I have found it. In the pollen of Microcachrys there is a similar excess of prothallial tissue. The grain has wings, however, but not of so definite a character as those of Dacrydium and Podocarpus, which, as is commonly known, bear two well-developed floating appendages. In Microcachrys a large percentage of the grains have three rather poorly developed wings, though the greater number are of the type which is characteristic of the higher members of the group. The winging of the grain is, as it were, in its experimental condition in Microcachrys, and the form is to be considered in this respect as a transitional one between Saxegothaea on the one hand and Dacrydium and Podocarpus on the other. ; Attention has often been directed to the biwinged condition of the pollen of the pines and podocarps as an indication of the probable affinity of the two groups. This view is no longer tenable, since the wings of the pollen in the latter are a development within the group itself, analogous but not homologous with those of the pine series. On the contrary, the rela- tionship of the microgametophytic condition in the Podocarpeae to that in the Araucarieae is increasingly apparent—RoBERT Boyp THompson, Unt- versity of Toronto. CURRENT LITERATURE BOOK REVIEWS North American Uredineae ProFEssor J. C. ARTHUR has begun his presentation of the Uredineae in the North American floras No one who has kept informed of our mycological literature, even in the most general way, needs to be told that the author is the om g American specialist on this group of fungi, and that this is the first attempt aph the rusts for the whole continent. Heretofore one has had to depend on fektited paper of Burritt dealing with the rusts of Illinois, and Fartow’s Host index of North American fungi, on the special papers by ARTHUR, Hotway, and others, and on the check lists and exsiccati that have been issued from time to time. The need of the work, therefore, cannot be questioned, and no one who has been engaged in a similar task can fail to appreciate the immense amount of effort it has required to bring it thus far toward completion. The part already issued, which includes descriptions of about 150 species and 34 genera, the writer understands to be but the advance guard of two or more parts to be issued later, as the material is worked up. ee The monograph is thoroughly well done. It presents a uniform treatment of description and terminology. The bringing together and describing anew all Stages, especially the pycnia which have largely been neglected before, make it especially valuable. It also reflects our latest knowledge of the life-history of the various species, to which the author has so long contributed with telling results. As to the real usefulness of the specific keys given under the genera, perhaps there _ May be some question, but the author no doubt has made them as valuable as they can be made. Mycologists have gone so far in describing new species of rusts - (and other fungi as well) chiefly because they occur on new hosts, that one fh _ Self-defense acquires the habit of disregarding keys, so far as possible, and uses _ the host and specific description a as the shortest route to identification. Then, too , too £, tis very difficult to discover t use in keys to families are necessary as characters to fill deliniences. In his keys ARTHUR has e use of both hosts and morphological characters, using the latter apparently whenever possible. Aside from the unquestioned merit of the work, the reviewer would dissent ngly from the point of view that compelled the author to split up old genera and _to coin many new specific names. These changes did not all appear for the first ‘ARTHUR, JosEPH CHARLES, North American Flora.—Uredinales (Coleosporia- Pipes, Aecidiaceae pars) 7:83-160, 1907. ay 468 BOTANICAL GAZETTE [DECEMBER time in the work under review, but they are all brought together here, and so focus our attention on the ninety (about) specific names (considerably over one- half) that bear ARTHUR’s name as their authority; and he is also responsible for sixteen (about one-half) of the genera. However, he is not quite so extreme in this respect as MuRRILL has been in his monograph of the Polyporaceae. ARTHUR has obtained part of his genera from new material and part by splitting up old genera, basing the new genera largely upon their possession of one or more of the O, I, II, III stages characteristic of the rusts. His familiarity with the rusts is such that he is able apparently, if given only the II stage, to tell what other stages it possesses, and so can place it in a genus. Judging from this past tendency to publish new species under the old recog- nized genera, a tendency he has not yet entirely lost, I expressed doubt to the late Professor UNDERWOOD, editor of the Flora, that ARTHUR would follow his Vienna paper in his treatment of the North American Uredinales. As he did follow it, however, I promptly received from UNpERWooD the following: “Some time ago you charged that ARTHUR was not possessed of the courage of his convictions in regard to his publication of genera in the Uredinales. I commend to your prayet- ful attention the second part of Vol. VII of North American flora, issued March 6, and move that it is time to have a retraction of that charge.” I herewith publicly make that retraction; but what will become of this nomenclature when some ambitious name-juggler revises our rusts fifty years hence, or possibly even after the next botanical congress!—G. P. CLINTON. NOTES FOR STUDENTS Turgor and osmotic pressure.—The relation between these stands in great need of accurate study. LEPEsCHKIN, a few months ago, discussed the matter before the German Botanical Society.2 After reviewing the terminology, he designates as turgor and turgescence the condition of tenseness of the tissues due to internal pressure in the cells. For quantitative purposes he defines as Zz turgor pressure (Turgordruck) the total pressure exercised by “cell contents’ upon the ‘‘cell walls;” but he evidently means by Zellinhalt the cell sap, for he explains that the Zellwdnde must be of plasmatic nature. By turgor tension (Turgordehnung) he designates the elastic elongation of the walls in any dimen- sion, wrought by turgor pressure. This only partly accords with the best usage in this country, where turgidity rather than turgescence names the condition, and turgor the internal pressure which produces turgidity, while turgor tension has seldom been considered quantitatively. LepEscHKIN then analyses turgor pressure into four components: (a) surface tension (Zentraldruck), vatying between 0.016 and 1.6 atmospheres, with a variation of 10-12 per cent.; () j swelling of the plasma (Quellungsdruck); (c) the osmotic pressure of substances = dissolved in the plasma; and (d) the osmotic pressure of the cell sap and the wall ? Lepescukin, W. W., Ueber den Turgordruck der vacuolisierten Zellen. Ber. Deutsch, Bot. Gesells. 26a: 198. 1908. 1908] CURRENT LITERATURE 469 liquids. But since neither b nor c, as the author himself points out, can exercise any effect on turgor pressure, it is difficult to see why they should be reckoned as components. The study of the osmotic pressure of the solutes in cell sap and wall is carried out with a show of mathematical formulae that look formidable, but the data are really not yet adequate for exactness. The experimental results show that the observed osmotic pressure is always less than the calculated, which is due to the greater or less but general permeability of the protoplasts, a feature too much overlooked hitherto, though clearly pointed out by various investigators and a priori obvious. The effects of temperature changes, especially between 0° and 20° C., were also examined. A warning against conclusions based on the exclusive use of KNO, as a plasmolytic agent without correction for permea- bility is given. In a later paper,s LepEscHKIN reports the results of a study of the per- meability of the pulvinus cells of Phaseolus and Mimosa, in which this proves to be surprisingly high. The solutes (except sugar) escape so rapidly when the tissues are brought into water, and especially into running water, as to reduce the apparent osmotic pressure (determined by the isotonic coefficient method) by 25 to 50 per cent. A change in the permeability of the plasma membranes may alter the turgor pressure by several atmospheres. LEPESCHKIN proposes to show in another article that such changes really occur (as has been hitherto assumed) under the action of various agents.—C. R. B. The blood of plants.—PALLADIN’s preliminary paper+ bears a rather striking title, which will be just enough if the theory proposed is fully established. Cer- tain colorless chromogens, probably products of protein decomposition, have been found in plants, and these become pigments (already familiar to common observation in various discolorations produced on cutting or crushing) under the action of oxygen in the presence of oxidases. These respiratory enzymes are therefore to be considered as pigment producers, and the respiratory pigments doubtless include a number of pigments already known, such as those of the indigo plants. PaxLapIN proposes to call all of them, irrespective of their chemi- cal composition, phytohematins, in recognition of the identity of their physiologicay significance with that of the hematin of the blood. To show this it was neces to find reductases in plant as in animal tissues, and PALLADIN announces - discovery. These enzymes reduce the respiratory pigments, which then n down to CO,, and H,0, etc. The following scheme shows the relation the various respiratory processes: 3 Peis W. W., Ueber die osmotischen Eigenschaften und den Turgor- « der Blattgelenkzellen der Leguminosen. Ber. Deutsch, Bot. Gesells. 26a:231~ 1go8, 4 PaLiapin, W., Das Blut der Pflanzen. Ber. - Deatack Bot. Gesells. 26a:125~ 1908. : 470° BOTANICAL GAZETTE [DECEMBER RIMARY PROCESSES SECONDARY PROCESSES Anaerobic enzymes (zymase, etc.) Oxygen of the air Catalase, reductase Respiratory oxidases Products of fermentation Phytohematins (alcohol and other substances) Products of respiration (CO.,, H20) To unify the respiration of animals and plants still further, it will be neces- sary to show that the oxygen from the air is not combined directly with the hemo- chromogen, but by the aid of oxidases; and this the recent discovery of these enzymes in the blood renders probable. The behavior of the colorless blood of the lower animals and the sap of plants is quite similar, according to this view. It is not to be supposed, however, that oxygen does not have other relations than to the chromogens; but these are neglected in the above scheme, which may be taken as only a partial representation of respiratory processes. In fact the more the matter is studied, the more complex and diversified appear the chemical changes subsumed by the word respiration.—C. R Fungi and hemicelluloses.—In ‘the hope of obtaining some insight into the action of fungi on their hosts, ScHELLENBERGS has investigated the behavior of a number of species, which can be cultivated on media of known composition, in respect to their decomposition of hemicelluloses. ‘Those used were several, the products of whose hydrolysis was known. Molinia coerulea among the grasses, Lupinus hirsutus among the Leguminosae, Phoenix dactylifera among palms, Impatiens Balsamina and Cyclamen europaeum with an amyloid reserve, and Ruscus aculeatus among the lilies furnished the hemicelluloses. On hydrol- ysis they yield respectively dextrose and xylose, galactose and arabinose, galac- tose and mannose, galactose and xylose, mannose and a little arabinose. A large number of fungi were tested. To explain their action, which he finds strictly specialized and very different from that on true celluloses, SCHELLENBERG has to assume the existence of at least four different enzymes, which he calls the Molinia, the Lupinus, the date, and the amyloid enzymes. Study of their behavior on dead and living plant parts permits similar conclusions. Thus fungi may be used to eliminate hemicelluloses from celluloses in unlignified tissues. The effect of fungi in the destruction of the plant constituents in the soil is prob- ably much more important than has been believed hitherto.—C. R. B. Jurassic plants.—SEwarp® has published the results of his study of collec- tions of Jurassic plants from Caucasia and Turkestan, sent by the Comité Géo- logique de Russie. The Caucasian collection contains representatives of the 5 SCHELLENBERG, H. C., Untersuchungen iiber das Verhalten einiger Pilze gegen Hemizellulosen. F ack 98: 257-308. 1908. ® Sewarp, A. C., Jurassic plants from Caucasia and Turkestan. Mém. Comité Géol. Russie N. Ss. 38: 1-48. pls. I-8. 1907. 1908] CURRENT LITERATURE 471 following groups; Equisetales (an Equisetites), Filicales (a species each in Marat- - tiaceae, Osmundaceae?, Schizaeaceae, and Cyatheaceae?), Bennettitales . Williamsonia), Ginkgoales (a Baiera), and Coniferales (a Pagiophyllum); i addition to these, there are four unassigned cycadophytes and two species of Podozamites. The collection from Turkestan includes approximately the same range of forms, adding a species of Dipteridinae and eight species of unassigned Filicales, but showing no Marattiaceae or Schizaeaceae; representing Gink, goales by two species of Ginkgo; and adding three Coniferales. In conclusion, the relations of these floras to those of other regions are shown by a table; and also the wide distribution of some of the species. Among the striking facts are the existence of so many species for a considerable time during the Mesozoic; the general uniformity in the composition of both the Rhaetic and Jurassic floras in different parts of the world; and the remarkable paucity of cycadean remains in the Turkestan beds.—J. M. C Light perception.—ALBRECHT has examined a large number of the endemic plants of northern Germany for the organs of light perception (lenticular epi- dermis, ocelli, etc.) to which HABERLANDT attributes the capacity of distin- guishing differences of light intensity. He finds? the organs very rare, and when they are present, nearly as common on the under as on the upper surface of the leaf, though it is clear that to the illumination of the upper surface alone is due the exact placing of the leaf in the fixed light position. No difference appeared in the adaptation of sun and shade leaves to the perception of light. He adduces again the experiments made by coating leaves with water, gelatin, and oil, as evidence against HaBERLANDT’s theory. After the reading of the paper, HABERLANDT spoke of the faulty methods in all the latter experiments, describing a mode of coating a part of the leaf with water and leaving the other part dry. On stimulating the two parts with light from different directions, the dry part was always the controlling one, even though the light was much weaker. -Haserianvt considers these experiments (to be detailed later) quite decisive. ‘It may be pointed out, however, that other factors than light are here ao and that the weight of evidence is clearly against HABERLANDT. —C.R Invertase of the date.—VrNSON has studied further® the invertase of greenr and ripe dates, in an endeavor to discover the reason for its inextractability from the green fruit. He finds that the tannin present does not make it insoluble, nor can it be extracted from ground pulp, so that impermeability of the cell ‘membranes is excluded. He proposes the theory “‘that green date invertase and possibly other endoenzymes are held in an insoluble combination by some con- stituent of the protoplasm. In some cases this combination may be broken -; Arprecut, G., Ueber die Perception der Lichtrichtung in den Laubblattern. _ Ber. Deutsch. Bot. Gesells. 26a:182-191. 1908. _ 8 Vinson, A. E., The endo- and ektoinvertase of the date. Jour. Am. Chem. Soc. 30:1005-1r020. 1908. Cf. earlier paper, Bot. GAZETTE 43:393- 1907. 472 BOTANICAL GAZETTE [DECEMBER down and the enzyme pass into solation while the protoplasm is living, but in others the combination may persist, even after the death of the protoplasm. The enzyme may be rendered soluble also by external chemical or physical influences. These probably act by destroying the integrity of the cell and allow- ing the contact of substances which have been localized in the living protoplasm. On maturity of the tissues the enzyme is generally liberated, possibly by auto- digestion or other profound change in the protoplasm.’”’—C. R. B. Fixation of free N.—Hannic, holding that H1ttNEr’s statement as to fixa- —* of free sora a6 by —— temulentum rested upon objectionable methods 1 the matter and confirms the latter’s results.9 About 100 per cent. increase in N of the crop over that in the seed is reported with the fungus-infested plants when N was excluded from the culture; whereas there was practically no increase in fungus-free plants. This is claimed to be the first ee of the fixation of free N by ectotrophic mycorhiza.— cE. B Zeitschrift fir Botanik.—On account of repeated and continued misunder- standings between the publisher of the Botanische Zeitung and its editors, FRIEDRICH OLTMANNS and Grar zu SoLMs-LAUBACH, the editors will sever their connection with that journal December 31, 1908, and, assisted by L. Jost, will found a new journal, Zeitschrift fiir Botanik, which will be published by Gustav Fischer of Jena. The journal will be a monthly, in the form of the Borantcat Gazette, and will contain both original investigations and critical reviews. The subscription price is 24 marks. CO, from dead tissues.—Nazoxicu reports in a preliminary paper’® that CO, is given off by dead seeds and seedlings of various plants, no matter how killed. He is apparently oblivious of the fact that CorELAND has already described the same phenomenon in dead water plants,t! and BECQUEREL in seed coats.12—C. R. B. 9 HANNIG, E., Die Bindung freien atmosphirischen oe durch pilzhaltiges Lolium hevialanciacin: Ber. Deutsch. Bot. Gesells. 26a: 238-246. 1908. ae NABOKICK, A. J., Ueber die Ausscheidung von ps saline aus toten Pflanzen- teilen. Ber. Deutsch. Bot. Gesells. 26a:324-332. 1908. tt COPELAND, E. B., Chemical stimulation and the evolution of carbon dioxid. Bot. GAZETTE 35:81-08, 160-183. 1903. ta BECQUEREL, PAUL, icc. sur la vie latente de graines. Ann. Sci. Nat. Bot. IX. 5:193-320. 1907. GENERAL INDEX ‘The most important classified entries will be found under Contributors and names and names of new genera, species, and varieties are printed in Rev scid- tase rai synonyms in #talic. A Absorptive ety = soil 224 Acorus Calam cqua, C, oink. ee Bc Adventitious ee 303 47" wa 399; parasitic 299; peri- cit ace Alpine Caen 422 n, J. P., work of 399 An A Narosiibes Scotti 311 Angiosperms S, mre Beco apres 315; origin of 315; primi 154 Antholithus Apple, disease of 70 Araceae ie hee: of 35 Araucarians 23 Arber, E. A. N., work of 154, 315 Archegoniatae, oct sad of 397 Ardisia erapazensi 113 "He len M., eae of 76 i ee edinales” 467 logy of 75 cytology of 3 n and hieonkvll 389. Sion Cane e F. 299, 321, 462 B Baccarini, P., work of Bacteria, ni Balan 06, ; 395 398, 400, 401, - 469, ya 47%, 472 Basecke, Paul, w — of 72 Basidiobolus, nuclear division 78 Bataille, eee F Flore monographique des Asterosporées” 152 473 Baumert, K., mee of 72 eans, s, diseas Bog water, toxic property of a rny, Th., ‘ Lehrbuch fn "‘Botanik” Beles lucidus 334; obliquatus 334; G. S., “Wood” 63 Fe ae = of a land flora” 56; work of 1 Brainerd, E., work of a Brandenburg, ghia es flora of 310 redema Diet Sho N. — nd Shafer, J. A., “North erican waa l, uschi, Dana, work o Buchanan, R. E. 316; one 399 Rerpasis, A. 387 Burli . L. 161 Burvenich, J. Ss work of 65 ushee, Grace L. 5 c Calorimeter, a new respiration 193 Cameron, F. K., work of 233 Campbell, D. Hi. work of 74, 313 Capparis Tuerc I Carnations, effect of oe gas 259 Centropogon Ceratiomyxa, sexuality in ag 474 Ceratozamia, seedling of Chamberlain, Charles J. aah , 80, pb 158, 159, 235, 237, 320, gh 399; 00 Characeae, pevingery of 397 China. conifers of 78 Chlor orophyil cand anthocyan 160; assimilati Chloroplasts eae of 77 Chlor 8 bdo a so canaegg of 393 Chromoso e Checaiathes emu um, uciatok ‘dation in 349 Chrysler, M. A. 72 Church, = H., “Types of floral mechan- ism’? r Cleistogamy 307 lidemia diffusa 112 Clinton, G. P. 67 O,, from dead tissues 472 Cockerel T. D. A., work of 79 "8 a, “ Grasse: s of Louisiana” 64 Ck ds alpine —— 422 Conifers of Chi 8 yc aoge= eines “and , G.F.299, 321,462; 8 >» O. My 303% Barnes, a; 23, 73> 74) 77; 78, 80, 152, 153, 157, 158, 60, 234, 236, 239. 305, 306, 320, 387, 389, 396, 398, 400, 401, 468, 469, 47 471,472; Blakeslee, A. F. 384; Brown - H. 445; Buchanan, E, > 7 ? 79> 80, 155, 158, 159, 235, 237, 320, 307, 399, 400; Chrysler, M. Clinton, G. P. 467; Coulter, J. M 35-56, 62, a e on ad to or) $m iS) os Ne) ~~ w > PP us fe} yt ws po 4, 315. 316, 317, 318, 319, 320, 470; Crocker, William 259; ty ss Danforth, C. H - 3 La 277; Heller, “Char 224; E. R. 386; €0. 170, 230, 312, 313, 317, aa Teles. E. C. 241, 311, 395, 397, 399; Kildahl, N. man, 7t, 81, Hodso: —_ nna 339, 464; Knight, L. L. 259; , «J» G, 402; w, 302; Ol E. W. 394; Osterhout, W. LP V. 83: S. B. 147; Peirce, G. J. 68, 193; Pond, R. H. 237, 390, 410; Ramaley, Franci ; Rosen, Joseph 224; Shull, G. H. 6, 74; Smith, Jol 21 ie ¢ F. L. 71, 239, 320, 391, 392; Stokey, INDEX TO VOLUME XLVI [DECEMBER Alma G. 160; Lee Reinhardt 4875 Thomson, R. 65; Yama ouchi, S. 75, 153; ee 383 "394, 396. Cook, Melville T.., cogs of 1 Co elan d, E. B., work of 472 Cornus florida, inoxphology of 79 as. =" mung und Ve- rerbung des “Gececaa? 148 Coulter, John M. 43, 56, 62, 6 7 16, 317, Crataegus coloradoides ae: Doddsii 381 Crocker, Willi Ciacinghainin, gues and embryo of 156 Cupule o: C pen ntagyna 109 Curvature, geotropic 158; cut turgor 73 Cycadophytes, fo nae 35 Cynomorium, mitosis in 396 Czapek, F., work 77 oe D : “eaten Alfre orth, GC. ii. : Yaphnosis radiata A ae. Darbishire, A. D., k of 68 Darwin, hist ee: of 387 Date, invertase of 471 Davis. C. ron ss daraquiniana 37 n edule, np of 357 Dipteris, sorus of 7 Diseases 69; bck: smut 392; grape 392; parse a 2395 pepper 70; sugar cane d : J gi Dacy, Wa Helen A. 203 Dudley, ur H., work of 77 umortiera, autoicous 80 E kerson, Sophia H. 221 239 , of Araceae 35; of Gnetum 1908] 43; of Nymphaea advena 238; of Peperomia 445; of Urticaceae 239 Endodermis of ferns 72 Endosperm, = Araceae 35; of Gnetum 45; of Potamogeton 160; respiration and ale decenion 390 Engler, A., “Das eats pt I5I rnst, A., work of 8 Escoyez, Eud., ie of 75 Ethylene, Heck 0 on carnations 259 Eurya guate — 109 Eustace, H. J., Fegatella, sexual condition in 384 erns, endodermis of 72; tracheae of 318 i Polytrichum 234; in of 388 nism 150; succession in prai s fo mete g S12 > shat ‘fossil flora of 79 Flowering plants and ferns 389 Foliar gaps, lege ales 248; iced aoe dendreae 243; copodiaceae 244; eer: 241; Pulieceas ne Sigil- ariae 243 Fomes curtisti 336 ‘rase r, H. C. L, work of 75, 394 okra , George F. 118 ‘ritsch, bs work of 388 Fruit, diseases = Ais Fulton, H. R., of 69, F ith ‘and PshiceMifones” bs: of Iowa Funkia, mitosis in 394 G Gallagher, F. C., work of 233 Gamble, J. S., work o: eae me te, of ae. Microcachrys 4 : Shane flabelliforme unre lucidum 3353 doboletus pseudoboletus tsugae 335: pseudobo- nha Bisse 335; pseudoboletus 336; tus 337; tsugae 335 Sees ae FD. work of 233 x Roe 156; Gates, Genetics, Conference on 60 Georgevitch, Peter M., wor f 80 n of zoospores 400 Ginkgo 2 Gnetales and Angiosperms 315 snetum Gnemon, embryo sac sac and em- 0 43 INDEX TO VOLUME XLVI 475 Goebel, K., work of 387, 396 Goffart, Jules work of 313 Gonolobus p asinanthus 114 Gow, Guate mal undescribed plants from 1og a afe, fe ork of 388 amin ¢ alvine dea: ee in 317 Craton anatomy of 312 Cece Victor, work o Griggs, R F., work of as rout, ., ‘“Mosses”’ 152 - J. Gui uignard, L., work of 77 Gwynne-Vaugha n, D. T., work of 318, 395 H nem G., work of 158 Halacsy, de, “Conspectus Florae eald, F. D., wo : Hidiecapian. ried 2 ie pa geotropism 2 30. icher, E., vines of 388 Heller, Charles 22 Ls lluloses, seal fungi 470 Holm, Theo. 422; worko eee a sb of 312 Hulth, J. M., “Bibliographia Linnaeana” op 230, 312, 313, 317; ‘eeaeaciek: movements 319; of living leaves 237 I Illuminating gas, ona on carnations 259 Invertase, of date Towa, algae and fur i of 399 Irving, Annie A., work 77 Taapetin, anatomy of ames, Edwin 78 Fanceewsi, © Ed., work of 320 , Ed ward C. 241, 311, 395, 397, 3993 ’ work of 1 15 Jones, Marcus E., aa willow family” 4 Jurassic plants 470 476 INDEX TO VOLUME XLVI K Kammerer, oh work of 388 Karzel, = ork of 388 Kauffm nigh H., work of 316 Kearne es co H., work of 77 Keeble, work of 68 Kidston, R., work of 395 Kildahl, N. "Johanna ns 464 Klebs, G. work of 66 Klinostats Knight, Lee I. 259 Knuth, Paul, “Handbook of flower polli- nation” 63 Kofoid, wc: te: “Plankton of Illinois Komaroy, V., ‘‘ Flora eer epee 64 Koorders, S H , work of rm Kras: F., work of 3 Kylin, Harald, “‘Studien iiber die Algen- flora” 151 L Lactarius and Russula 152 Lecdnatales “aa tubes in 153 Land, Leaves, alpine grasecs 438; in autumn 39; hygroscopic movements of 237 a E., “ Kryptogamenflora”’ Lapeachin, W. W. 468 piles Francis J a 2 wor of 74 Lignier, O., w: Light ci ei ar “iruksion from 72 Lindemuth, H., work of 78 Litschauer, ip work of 387 Lloyd, F. E., “The physiology of sto- ma 40eW, Osc L T 302 Lopriore, G, work of 388 Lubimenko, W., work of Levins albus, lateral roots of 413 Lycopodiaceae, sporangia of 159 Lycopod with seedlike setae 158 Lycopsida, foliar gaps in 2 M Soe J., wor & of 65 [DECEMBER Masters, Maxwell T., work of 78 Melia, Azeda rach, adventitious a 303 iS ihseeal = = <) n =F =] a 5 Qf ES p 2 4p ai te! QP Ge © hs rod Pooch, Otto, work of 155 Potamogeton, embryo and endosperm of 160 Aes beg formation 81; floral suc- cessi aa Priestl : 3 x ork of 77 Rainn tse ert. work of 236 Proteases 76 Prothallia, dwarf male 158; of Kaulfussia and Gleichenia 313 Protoplasmic relations 320; streaming 50 Przibram, H., work of 388 eine 310 Pteridophytes, phylogeny of 240 R Raciborski, M., — of 388 Radioactivi dee Ramaley, Fra is 983 sats a pe ee of leaves 313 Reddick, Donald, work of 239 Red gum, sap rot of 79 : Reduction, . Polytrichum 234; in Oenothera = Resin ack in bark of Picea 386 Respiration, a new calorimeter 193; en- dos es ermic ae. Revi Arthur’s ‘‘Uredinales” 467; Bataille’s “Flore monographique des Asterosporées’’ 152; Bokorny’s ‘“ Lehr- buch der Botanik’’ 308; Bose’s ‘Plant response” 58; Boulger’s “‘Wood” 63; ican trees” 62; h’s “Types of ral mechanism” 1 ocks’s Gr s of Louisiana”’ 64; s Pflanzenrei ib x55 Grout’s ‘‘ Mos: 152; Hala csy’s “Conspectus Florae Graecae” 152; Hulth’s “ Bibliographia willow Linnaeana” 308; Jones’s ‘‘The will ly” 64; Knuth’s ‘Handbuch o pollination” 63; id’s “Plankton of Illinois River 49 Komarov’s ‘‘Flora Manc e” 64 mer’s ‘‘Text-book of botany and pharmacognosy” 231, in’s pe n iiber die Algenflora’”’ 151; Lemmermann’s “ Kryptogamenflora” 310; d’s “The physiology of stomata” 62; Noll’s ‘“Text- botany” 3053, Nordstedt’s ‘Index Des- midiacearum”’ 152; Schenck’s “‘A text- of botany” 365; Solereder’s “Systematische Anatomie der - onen” 153 ven’s ‘‘Plant anat- Richter, O., work of 387 Riella 3 Ritzerow, Helene, work of 397 Roots, alpine grasses 432; lateral emer- Sisyrinchium 182 Rorer, J. B., work of 7° Rosendahl, re “0. work of 76 umpf, — 320: se xual reproduction in 314 osch, S., work of 3 S Salts, tolerance for 77 Samec, M. k of _ 478 Sap rot of red gum 7 Sargant, Ethel, work “ : s4 , work o bm and stoc cott, W S ork of 23 Seedling, of Gases s 203 Self-digestion and endospermic respira-. tion 390 rit z work of ard, A. Sex, Caenn on 148; in pists 319; in Ceratiomyxa 80 Shaw, F. J. F., work of - Shull, George H. 61, Sieve tubes 319 Sisyrinchium, anatomical studies 170; leaves 185; rhizomes 184; roots 182 Skraup, Z. H., wor Ac . Fd Smith Pe Se Don Soil, absor rptive ones of 224; fertility 3 Silene phoes Tuerckheimiana rr lereder, H., “Systematische Aunisthae edonen” 153 ed 302 , prairie-grass formation 81, 277 Sphaeropsis 392 A maine ones spe of 319 Spermato oO Sporangiophore pa Stevens, F. L. 71, pot ei 392, 392 S Wm. C., “Plant anatomy” 306 Alma G. 160 Stoklasa, Js work of 3838 tomata, number and size 221; physi- ology Stoward, Frederick, work of 391 tr asburger : E., Pee ext-book of botany” 305; work of 38 neat pe Phylidcladus 339 trohmer, M., work of 388 phaen: Siege 113 ris7 of 3 Sweden, sehr eg va phan Sykes, M. G., work of je 6 394 INDEX TO VOLUME XLVI [DECEMBER Symbiosis 68 Sym plocar ps morphology of 76 Synapsis 232; in Oenothera 7 Synchytrium, cytology of 159 it conan gees S 27 hom of a tissues 398 quantitative mons ee oO er Bae | Trees a of 87 Tswett, M., of 239, 2 Turgor, r and 7 meee 433 ead osmotic snag uzson, Se work of 397 U Ulva, cise re of 399 Uredineae, N. Am. 4 Urtiaccae aera sac and embryo 239 Vv Van appre elma J. and W., work eee Variegati ei Vascular anatomy, of Dioon 357 Van Tieghem, Ph., work of 117 Veronica, anata of 312 Vicia faba, lateral roots of 412 H., work of at. Vinton, A. E., work of 471 Von Guttenberg, H. Ritter, work of 236 Von Hayek, August, ‘‘Flora von Steier- ote 309 Von Héhnel, Fr., work of 387 Von Weinzierl, work of 388 Von Wettstein, R., work of 388 w “Om Planterigets Livs Weg Ej i nue of 394 INDEX TO VOLUME XLVI 479 Went, F. A. F. C., work of 318 ; a : eat, morph 77 Wieland, G. R., work of 75 Yamanouchi, Shigéo 75, 153: 232, 393s i 394 396 of the flowering plants and ferns” 309 _— Zeitschrift fiir Botanik 472 Wilson, C. S., work of 239 Zikes, H., work of 3 Wolf, F. A., work of 392 Zoospores, rinse 400