AER THE BOTANICAL | Rees THE UNIVERSITY OF CHICAGO PRESS CHICAGO, ILLINOIS THE CAMBRIDGE UNIVERSITY PRESS LONDON AND EDINBURGH THE MARUZEN- eh amg TOKYO, OSAKA, KARL W. HIERSEMANN LEIPZI THE BAKER & TAYLOR COMPANY NEW YORK CK \ Burs THE 4 BOTANICAL GAZETTE EDITOR JOHN MERLE COULTER VOLUME LYVII JANUARY-JUNE, 1914 WITH TWENTY-NINE PLATES AND ONE HUNDRED AND FIFTEEN FIGURES THE UNIVERSITY OF CHICAGO PRESS CHICAGO, ILLINOIS ae z oeeitemeerieeene { ee TABLE OF CONTENTS The development of Magnolia and Liriodendron, including a discussion of the primitiveness of the Magnoliaceae (with plates I-III) The maturation arse in Smilax herbacea Au plates IV-VI) - Comparative histology of alfalfa and clovers with eight figures) ~ - The réle of oxygen in germination., Contributions from the Hull Botanical Laboratory 181 - Studies on the reactions of Pilobolus to — stimuli (with twelve figures) - Morphology of Thismia americana. Contribu- tions from the Hull Botanical pare: 182 (with plates VII-XI) -~ - Concerning the presence of diastase in certain red ga : = The male eumetophyte of Abies (with fifteen figures) - ~ * The anatomy of Osi ten: Contri- butions from the Hull Botanical ee 183 (with sixteen figures) - Some effects of colloidal metals on S acetal vith four figures) - - 5 The function of manganese in planta - - - The development of the prothallium of Camp- tosorus rhizophyllus (with plates XII and and eight text figures) - = - - The effect of shading on the transpiration and assimilation of the tobacco oo in Cuba (with one figure re) - ‘ A preliminary inquiry into the significance of tracheid-caliber in Coniferae Note on the ascosporic condition of the genus Aschersonia Montagne (with seven figures) - Morphological instability, especially in Pinus radiata (with plate XIV and two text figures) - bf Willis Edgar Maneval Marion G. Elkins Kate Barber Winton Charles A. Shull - Hally D, M. Jolivette Norma E. Pfeiffer E. T. Bartholomew A. H. Hutchinson Loren C. Petry W. D. Hoyt W. P. Kelley F. L. Pickett Heinrich Hasselbring Percy Groom Roland Thaxter Francis E. Lloyd PAGE vi CONTENTS [VOLUME LVII Life history of Porella platyphylla. Contributions from the Hull Botanical Laboratory 184 (with plates XV and XVI) - - - - - Florence L. Manning The effect of climatic conditions on the rate of growth of date palms (with one figure) - - A. E. Vinson The probable origin of Oenothera Lamarckiana Ser. (with plates XVII-XIX) Hugo De Vries The spur shoot of the pines (with sates XX- XXIII and two text figures) - - - Robert Boyd Thomson A physiological study of the germination of Avena fatua. Contributions from the Hull Botanical Laboratory 185 (with thirteen figures) - - W.M. Atwood Undescribed plants from Guatemala and oth Central American Republics. XXXVIII - John Donnell Smith The ovary and embryo of Cyrianthus sanguineus. Contributions from the Hull Botanical Lab- oratory 186 (with aes XXIV and three text figures) - : _ - - - Margaret Elizabeth Farrell Winter as a factor in the xerophily of certain ever- green ericads (with twelve text figures) - - Frank Caleb Gates The morphology of Araucaria brasiliensis. II. The ovulate cone and female gametophyte (with plates XXV-XXVII and two text figures) - - L. Lancelot Burlingame The origin of Diccieiae beciies from the Hull Botanical Laboratory 187 itt plates XXVIII and XXIX and two tex figures) - = -- - John M. Coal and W. J. G. Land A method of ining the temperature of the paraffin block and microtome knife. Con- tributions from the Hull Botanical -acuaals 188 (with two figures) - - W. J. G. Land BRIEFER ARTICLES— A method of handling material to be imbedded in paraffine (with one figure) = - - Winfield Dudgeon The relation between the tide. stream and the absorption of salts - - - - Heinrich Hasselbring The type species of Danthonia A. S. Hitchcock - A method of handling material to ol imbedded i nb paraffine (with one —_ - Elda R. Walker A correction - —. e e e E. M. East. 8 bo 4 445 33° 334 “VOLUME LVI] CONTENTS vii Successful artificial cultures of Clitocybe illudens and Armillaria mellea (with three figures) - - V.H. Young 524 The amount of bare ieee: in some mountain grasslands” - - - - Francis Ramaley 526 The oxidases of acid tissues - G. B. Reed 528 The type species of Danthonia - ee N. on sua J. Francis Macbride 530 Maturation in Vicia - - Lester W. Sharp 531 CURRENT LITERATURE - - - - 74, 154, 239, 332, 437, 532 For titles of book reviews see — under author’s name and reviews Papers noticed in ‘‘Notes for Students” are indexed under author’s name and subjects DATES OF PUBLICATION No. 1, January 16; No. 2, February 14; No. 3, March 14; No. 4, April 15; No. 5, May 16; No. 6, June 19. rd hy rd td rd ty ar) ERRATA Vor. LVI 491, line 4 from bottom, for accitillo read aceitillo. - 494, line 4 from bottom, for B. incisa (L.) G. Don read B. incisa (Ker) G. on. VoL. LVII 308, footnote, for LXII read LXXII. 415, line 12 from top, for ongam read longam. 417, line 9 from top, for dela read de la. 424, line 18 from top, insert comma after lata; and for petiole read petiolo. 424, line 23 from top, for insertionen read insertionem; and omit comma after insertionem - 430, legend of Fig. 3, re petals read perianth; and for sepals read stamens. THE BOTANICAL GAZETTE Editor: JOHN M. COULTER * JANUARY ro14 The Development of Magnolia and Liriodendron, Including a Discussion of the Primitiveness of the Magnoliaceae Willis Edgar Maneval The Maturation Phases in Smilax herbacea Marion G. Elkins Comparative Histology of Alfalfa and Clovers Kate Barber Winton The Role of Oxygen in Germination Charles A. Shull Briefer Articles A Method of Handling Material.to Be Imbedded in Paraffine Winfield Dudgeon The Relation between the Transpiration Stream and the Absorption of Salts Heinrich Hasseibring Current Literature The University of Chicago Press CHICAGO, ILLINOIS, U.S.A. Agents THE CAMBRIDGE UNIVERSITY PRESS, London and Edinburgh M WESLEY & SON, Lendon KARL W. HIERSEMANN, Letpzig THE MARUZEN-KABUSHIKLKAISHA, Tokyo, Osaka, Kyoto Che Botanical Gazette A Montbly Journal Embracing all Departments of Botanical Science Edited by JoHN M. CouLTer, with the assistance of rh members of the botanical staff of the University of Chic Issued January 16, ee Vol. LVII CONTENTS FOR JANUARY 1914 No. { THE DEVELOPMENT OF MAGNOLIA AND LIRIODENDRON, INCLUDING A DIS- CUSSION OF THE are are oe ae MAGNOLIACEAE rare PLATES i-1n). Willis Edgar Maneval THE gt tad gs be meas IN Petes verre Avie PLATES 'v-—v1). Marion shat og ihe cota i tebe OF hE She mak x bi Stee (WITH EIGHT FIGURES). + Winton ‘g s 2 5 # 53 THE eat aA OXYGEN IN GERMINATION. CONTRIBUTIONS FROM THE Hutt BoTranicaL RATORY 181. Charles A. Shull - - - - - - - - i 64 BRIEFER ARTICLES ETHOD OF these Ms oreee TO i gee ge | IN So cn oh (WITH ONE digits dy, Winfield is THE RELATION rng i THE ‘TeansprRation Sraeaw A AND THE Abkcinibins oF SALTS. Heinrich Hasselbrin : i Z : Z CURRENT eer eates $5 Amie rd Ee eG eS ea eae oe eee eae THE SIMPLE PLANT BASES. 5 MINOR NOTICES - = ce ~ ke ~ “ = ig * . Q ae, wn 0, L? NY N al | BOTANICAL GAZETTE, LVII MANEVAL on MAGNOLIACEAE 1914] MANEVAL—MAGNOLIACEAE 31 Fic. 16.—Longitudinal section of part of anther; microspore mother cells in oe X 300. 17.—Transverse section of anther; tapetum and sporogenous tissue bifferentiatel: X 350. ’ 18.—Transverse section of anther; tetrads of microspores; > 300. Fic. 19.—Section of pollen grain with reduced number of chromosomes; Fic. 20.—Uninucleate pollen grain; 350. Fic. 21.—Binucleate pollen grain; 350. Fic. 22.—Longitudinal section of ovule with archesporial cell; 300. Fic. 23. Pipe ero section of ovule through megaspore mother cell and tapetal cell; > 500. Fic. 24. A onpieadionl section of ovule; megaspore mother cell; integu- ments; 300 IG. 25.—First division of megaspore mother cell; 350. Fic. 26.—Megaspore mother cell fol ia X 350. Fic. 27.—Tetrad of megaspores; 35 Fic. 28.—Longitudinal section ‘hich ee embryo sac; X 350. Fic. 29.—Longitudinal section through tetranucleate embryo sac; 350. Fic. 30.—Longitudinal section through mature embryo sac; 350. Fic. 31.—Micropylar end of embryo sac; pollen tube; two-celled endo- sperm; X 600. Fic. 32.—Longitudinal eget of micropylar end of embryo sac showing early condition of endos Fic. 33.—Section of Souci hans X 500. Fic. 34.—Section of eight-celled embryo; X 500. Fic. 35.—Longitudinal section through an older aber » & 500. Fic. 36.—Longitudinal section of embryo and suspensor; X 300. Fic. 37.—Longitudinal section of embryo from mature seed; X 50. Fic. 38.—Transverse section of petiole; X 50. Fic. 39.—Transverse section of portion of a fibrovascular bundle of a petiole; sk 300 IG. nies section of portion of peduncle; X 50. THE MATURATION PHASES IN SMILAX HERBACEA MARION G. ELKINS (WITH PLATES Iv—V1) The material for this paper was collected in the spring of 1909 in the vicinity of New Haven, Connecticut. Both staminate and pistillate flowers were obtained with a view to studying nuclear conditions in both sexes. Staminate flowers, gathered on May 14, supplied nearly all the stages desired, as the flower buds in each inflorescence exhibited varying degrees of development. The pistillate flowers, maturing more slowly, were fixed May 26 and June 2. The series obtained from this material was very incom- plete, only a few stages of the prophase of the heterotypic division being procured. Traces of the megaspores were visible in some flowers, but in most cases their location was represented by 4 dark, irregular line which suggested crushing or imperfect fixation. Various killing fluids were used, but only two proved of any value, namely Flemming’s fluid (weaker solution) and Juel’s fluid. Sections were cut 6u in thickness and stained with Flem- ming’s triple stain or Haidenhain’s iron haematoxylin. The maturation phases in the microsporangium The earliest observations of the sporogenous tissue were made after the telophase of the last vegetative mitosis and before the differentiation of the tapetum. Excluding the outer layer of cells in this tissue, which eventually become tapetal, the remaining cells are virtually pollen mother cells, and after a slight increase in size are ready for the phenomena characterizing meiosis. The nuclei of the young spore mother cells show small chromatin bodies or granules of variable size scattered through the finely granular linin meshes. A distinct reticulum is not present. Often the chromatin bodies may be seen in pairs or groups of four, but their distribution is generally irregular and does not warrant a conclu- sion oats pairing is their typical arrangement. Gazette, vol. 57] [32 1914] ELKINS—MATURATION IN SMILAX 33 A multinucleolate condition is typical of the nuclei of these cells. The nucleoli are variable in number and size and often somewhat angular in outline; several small bodies appear attached to the nucleoli (figs. 2, 3), which resemble papillae and will be so designated during the following description. As late as diakinesis nucleoli have been observed with one or more of these papillae. In the material prepared with the triple stain the nucleoli of the heterotypic prophase show one or more glistening white spots; these were at first considered to be vacuoles, but there is also the - possibility that they represent papillae viewed on the upper surface of the nucleoli. The microspore mother cell in the early prophase is sometimes uninucleolate, though more often provided with two large nucleoli. However, at synapsis there is never more than one large nucleolus, which is no longer angular and is usually provided with a single papilla. In connection with the study of the microspore mother cells of the early prophase, observations were made on the somatic nuclei of the nucellus. The appearance of the chromatin bodies and the nucleoli in such a nucleus (fig. 27) agrees very closely with that given for the nuclei of the young spore mother cells. The author believes the uninucleolate condition (fig. 5) to be the result of union of the nucleolar elements. Fig. 1 shows two nucleoli connected by a short, deeply stained strand, while fig. 2 shows two nucleoli in a later stage of fusion. The papillae described above are probably nucleolar fragments or very small nucleoli which are in the process of fusing with the larger nucleoli. Fusion of all the nucleolar matter apparently does not take place; as late as diakinesis small globular bodies are often found which are dis- tinct from both the nucleolus and the chromosomes. The papil- late condition of the nucleolus also persists until the nucleolus disappears at the metaphase. Gates (14) describes parallel phenomena in the sporogenous cells of Oenothera rubrinervis. Here the nucleus is provided wi one large nucleolus accompanied almost invariably by smaller nucleolar bodies. Fusion of these bodies takes place; the number present in later stages depends on the amount of fusion. This seems to vary. One large nucleolus is always present until the 34 BOTANICAL GAZETTE [JANUARY disappearance of the nuclear membrane; there are also one or two small nucleolar bodies which remain through the metaphase of the heterotypic division and are sometimes observed on the homotypic spindle. . This papillate appearance of the nucleolus may be interpreted in quite another way, namely, as a process of chromatin budding from the nucleolus. CarpirF (5) figures nucleoli with similar papillae in young spore mother cells, and suggests that a papilla may represent the beginning of a chromatin thread formed from the nucleolus. Miss NicHots (32), in a study of several species of Sarracenia, concludes that the nucleolus of the pollen mother cells elaborates the chromatin, and figures nucleoli with small bodies attached, which represent the chromatin emerging from the nucle- olus. DarwinG (7) describes the budding of chromosomes from the nucleolus in the prophase of the heterotypic division in Acer Negundo. In the somatic nuclei of the root tip of Phaseolus, WaceER (43) describes the nucleolus as being connected with suspending fibers along which the chromatin from the nucleolus passes. These fibers become much thickened with the accumula- tion of chromatin and finally break up into chromosomes. Wi the loss of chromatin the nucleolus shrinks, becomes detached from the chromosomes at the metaphase, and finally disappears. The conclusions of WAGER, however, are disputed by MARTINS Mano (26), who made a similar study of Phaseolus and concluded that the chromosomes are not of nucleolar origin. He advances this interpretation: at the telophase certain portions of the chro- mosomes are drawn out into threads which anastomose and form a chromatic reticulum. In the following prophase the reticulum gradually assumes the form of bands with connecting fibers; the bands contract and ultimately break up into chromosomes. The appearance that WAGER describes as “suspending fibers’? MARTINS Mano interprets in another way. The nucleolus is formed inde- pendently from nucleolar substances, but in close contact with chromatin elements. When the perinucleolar vacuole is formed, there is a consequent repulsion of the nuclear reticulum; certain parts of it remain attached to the nucleolus by reason of the elas- ticity and viscosity of the chromosomes. Ii the nucleolus furnishes 1914] ELKINS—MATURATION IN SMILAX 35 any substance to the chromosomes it is not done by means of “suspending fibers.” Fig. 3 seems to show a condition like that destribed by DaRLInG and WaAceER. There is a great similarity between the papillae attached to the nucleolus and the chromatin bodies lying free in the linin network. On the other hand, the presence of numerous darkly staining granules in the sporogenous and somatic nuclei and the presence of a nucleolus as late as diakinesis argue against the resolution of the nucleolus into chromatin bodies. SyNAPSIS.—The term “‘synapsis’’ has been defined in two ways. Most botanists use the word to denote the period of maximum contraction of the chromatic elements in the prophase of the hetero- typic division. Zoologists call this stage “synizesis’”” (McCLUNG 25, JORDAN 20) and assign the name ‘“‘synapsis’’ to the period of approximation of parental chromosomes. GREGOIRE (17) de- fines synapsis as covering stages from leptonema to strepsinema. In this paper ‘“‘synapsis” will be considered as synonymous with “‘synizesis.”’ The presynaptic phases in Smilax herbacea are apparently simple; the linin mesh contracts (fig. 6), drawing the chromatin bodies together into an increasingly close proximity. As there is no chromatic reticulum or pairing of thin filaments, the process resolves into the mutual approach of chromatic bodies. MIvyAKE’s (28) description of chromatin behavior in Lilium corresponds closely to this account. During synapsis (fig. 7) the nucleolus is almost invariably at one side and projecting from the synaptic mass; delicate linin threads bridge the karyolymph and connect the chromatic ball with the nuclear membrane. For a time the granu- lar nature of the chromatin is maintained; toward the end of synap- sis, however, the chromatin becomes arranged in a much interwoven beaded filament (fig. 8). Views in regard to synapsis and its importance range from those that discard it as of no significance or due to faulty technique (SCHAFFNER 37) to those that assign to it the function of bringing together parental elements in closest union and mutual influence. Lawson (22) denies the presence of any real contraction and states that the phase known as synapsis is due to an enlargement of the 36 BOTANICAL GAZETTE [JANUARY nuclear cavity, the chromatic mass remaining the same size. In 1899 GUIGNARD (19) reported the absence of synapsis in Naias major. CARDIFF (5) has described this phase as the deferred culmination of fertilization. The later tendency is to admit its presence as a normal stage and to consider it only a time of great shortening and thickening of chromatic filaments (GREGOIRE 17, Bercus 2, Davis 8). GrEGorrE in his discussion of synapsis admits that it is not a universal phenomenon. When it does occur, he believes it can have no réle to play in the process of reduction, but is itself a result of certain nuclear activities. He further suggests that the appearance of synapsis may be empha- sized by the growth of the nuclear cavity or by an artificial contrac- tion caused by fixing reagents enhancing the natural contraction. GATES (16) states that it is evident many changes take place during synapsis, though there may be no interchange or influence between homologous chromosomes. He points out (15) that such influences may take place at any time during the sporophytic phase of the life cycle. Ernst (12) considers synapsis normal, otherwise a similar sensitiveness to fixing fluids ought to show in vegetative mitosis of corresponding stages. There is one possi- bility favoring artifact, namely, that the progressive stages of mitosis may be accompanied by chemical changes in the chromatic substance which cause different reactions to fixing fluids. It is difficult, however, to conceive of a chemical change occurring in 4 heterotypic prophase which would not also occur in a somatic prophase. Moreover, there is no experimental basis for this view, though NEMEC (30) by microchemical tests demonstrated differ- ences in the chromatin of resting and dividing nuclei. The contraction of the nuclear contents is very striking in Smilax herbacea (cf. figs. 5, 6, 7), and is without doubt a normal condition. It is difficult to assign synapsis a réle in Smilax. It is evident that the appearance of the nucleus after synapsis differs markedly from the preceding conditions; the chromatin elements pass into synapsis as distinct bodies and emerge in a homogeneous filament. Until more light is thrown upon this phase, we can only vaguely state that synapsis may facilitate the proper placing of the paired parental elements in the chromosomes and the chromo- 1914] ELKINS—MATURATION IN SMILAX 37 somes in the spireme. The chromosomes in Smilax herbacea never appear as definite units until the segmentation of the spireme. PostsyNApsis.—The much coiled filament of late synapsis emerges as a fairly thick thread slightly beaded (fig. 8), which later assumes a homogeneous character. The double nature of the spireme is early discernible (fig. 9). With the continued loosening of the knot the split is sometimes obliterated, but the spireme as it is distributed throughout the nuclear cavity is distinctly double; this separation of previously paired* chromatic elements does not appear simultaneously in all parts of the spireme (figs. 10, 11, 12). Shortening and thickening of the spireme proceeds as usual, fol- lowed by a sort of semi-segmentation of the double filament. At intervals along the spireme occur places where each longitudinal half is apparently constricted to a delicate thread (fig. 13). This appearance is due doubtless to incomplete transverse segmentation with subsequent pulling apart of the double segments; the attached portions thus are drawn out into fine threads. The bivalent chro- mosomes resulting from the completion of the transverse division of the spireme are long and slightly twisted about each other (figs. 14, 14a). Though not a typical strepsinema, this condition corresponds to strepsinema as described by GREGOIRE (17). The shortening and thickening process continues, resulting in the characteristic diakinetic gemini, the univalent halves of which lie, indiscriminately (fig. 15), parallel, at right angles to each other, or in the form of V’s or X’s. Traces of linin threads can be seen attached to the ends of the chromosomes. The nucleolus is present at this stage (though not figured), but disappears before the metaphase. Small globular bodies scattered about among the gemini appear in many of the nuclei in addition to the nucleolus. These are probably small nucleolar bodies as previously described. MeETAPHASE.—Many of the gemini retain the semblance of a V on the spindle (fig. 16), though occasionally the homologous chromosomes are oriented in a straight line. Intermediate stages occur between these two types of orientation. In many cases the chromosomes show a distinct splitting while at the equator; this is more marked as the chromosomes pass toward the poles, though t Previous pairing is assumed to have taken place. 38 BOTANICAL GAZETTE [JANUARY it does not become a complete fission (fig. 19). This is without doubt a genuine splitting preparatory for the homotypic mitosis. As the first division is merely a separation of chromosomes, the true mitosis being deferred until the second division, it is not sur- prising that the fully formed chromosomes exhibit a tendency to fission, the normal consequence of a mature condition in meriste- matic cells, long before actual mitosis is permitted to take place. FARMER (13) expressed a similar idea when he said ‘with the in- ception of karyokinetic activity the spireme thread undergoes the longitudinal fission characteristic of ordinary somatic division, although the actual separation of these longitudinal halves is deferred until the next mitosis.”’ The separation of the chromosomes at the equator and their passage to the poles takes place in the usual manner. Frequently the chromosomes of one or more pairs separate and move away from the equator earlier than the majority (figs. 17, 18). INTERKINESIS.—At the telophase the chromatic elements appear in the form of a spireme which is disposed about the pe- riphery of the newly formed nuclear membrane. The daughter nuclei are usually elliptical, though sometimes they are slightly curved, presenting a concave surface toward the equatorial plate. Miyake (28) finds in Lilium Martagon a partial formation of a thread, but usually there is little change in the form of the chromo- somes during interkinesis. In Smilax herbacea the split which was observed in the metaphase and anaphase, homotypic in nature, is sometimes faintly discernible, but usually lost to view. Vacuola- tion of the chromatin band, if it may be said to occur at all, is very slight. In fact, the transitory character of this phase does not call for extensive alveolization. We have here in reality a prophase of the homotypic division. Grécorre (17) describes the heterotypic division as a process intercalated in the prophase of the homotypic division. Conditions reported during interkinesis vary in different plants. In Oenothera gigas, according to Davis (9), the daughter chromo- somes maintain their form and distinctly show the homotypic split, thus giving an appearance similar to diakinesis. GarTEs (16), describing the same species, states that some of the chromosomes 1914] ELKINS—MATURATION IN SMILAX 39 pass through interkinesis in a compact condition, while others become vacuolate. In Nephrodium molle (YAMANOUCHI 45) the chromosomes become vacuolate, but their identity is not lost. ALLEN (1) cites the formation of a spireme during the telophase of Lilium canadense. In Pinus and Thuja (Lewis 24) the identity of the chromosome is completely lost. NicHots (31) reports a similar condition in Juniperus. Homotypic piviston.—In preparation for the second division the nuclear membrane disappears’ and is succeeded by the forma- tion of a spindle whose axis corresponds with the greater axis of the daughter nucleus. The daughter spireme is at first spread out on the spindle from pole to pole (fig. 21); later the chromatic mass contracts (fig. 22) and occupies a position at the equator of the spindle. At this time the spireme seems to be resolving into chromosomes (fig. 22). Throughout these stages there is no sign of a double filament: in fact the whole structure is indistinct. Figs. 23 and 24 show fully formed chromosomes which have split into daughter chromosomes. A side view of the spindle (figs. 23, 24) presents chromosomes apparently shaped like dumb-bells. A comparison of the above mentioned figures with fig. 25, a polar view of the equatorial plate, explains the actual condition. The daughter chromosomes are paired in the form of V’s;_ the open ends of the V’s are turned outward, the arms of the V’s are nearly at right angles to the axis of the spindle. The appearance of the chromosomes of figs. 23 and 24, as described above, is due to the fact that only the tips of the chromosomes at the open ends of the V’s can be seen; the seeming connection between the chromosome tips is occasioned by an indistinct view of the apices of the V’s. The separation of the daughter chromosomes as in the first division is not simultaneous. Fig. 23 shows a chromosome well on its way toward one pole before its sister chromosome, or the 2 LAWSON in a recent paper (23) claims that the nuclear membrane does not varias ponies or collapse as _— —, said ase to be the case. On the contrary, Changes in the quantity and form of the chromatin previous to the metaphase are apparently accompanied by a change in the osmotic relations of the karyolymph. As a result of this there is a gradual decrease in the volume of the nuclear vacuole until the nuclear membrane closes in about the chromosomes; each chromosome becomes a single osmotic system. 40 BOTANICAL GAZETTE [JANUARY other chromosomes, have moved far from the equatorial plate. Fig. 26 also shows chromosomes in the anaphase lagging behind at the equator, while the majority have nearly reached the poles. CHROMOSOME NUMBER.—The metaphase of the second division represents the most favorable opportunity for the chromosome count. The chromosome number, however, was not determined with any finality. In diakinesis the chromosomes, though few in number, are so large that they obscure each other. A compari- son of the counts attempted during diakinesis and the second metaphase places the haploid number of chromosomes at either 12 OF 54; Postsynapsis in the megasporangium The difficulty of obtaining maturation stages of the megaspore mother cell discouraged a study of meiosis in the pistillate material. Of the many slides prepared, the majority showed synapsis; in addition only a few postsynaptic stages were procured. The nuclei of the megaspore mother cells are larger than those of the micro- spore mother cells, and when desirable stages are found they are exceedingly favorable for study. The first stage noted after synapsis represents the nucleus as containing a mass of loosely interwoven filaments undivided and slightly beaded (fig. 28). The filaments thicken (fig. 29) and split longitudinally (fig. 30). Before the spireme breaks up into the bivalent chromosomes, it passes into strepsinema; the halves of the double filament draw apart, twist about, and cross each other (fig. 31). Attenuated portions of the spireme may be observed; transverse segmentation has begun and isolated pairs of chromo- somes may be seen near the periphery of the nucleus. In diakinesis the paired chromosomes occupy many positions with respect to each other, seldom lying strictly parallel. In fact, the description of diakinesis in the staminate loculus applies here. In fig. 33 several of the chromosomes offer a trace of a split, probably a precocious homotypic fission. In the microspore mother cells this split was not observed until the metaphase. This homotypic fission is described as occurring earlier in plants studied by the metasyndetists (Mottrer, Lewis, FARMER, DAVIS, 1914] ELKINS—MATURATION IN SMILAX 4I and others). Mortrier (29) finds gemini in Tradescantia having double paired segments. This doubling is supposedly due to the reappearance of a split in the spireme which is believed to be a genuine homotypic fission and hence comparable to the split found in the paired segments of gemini in Smilax. Mode of reduction The mode of reduction in Smilax herbacea is essentially para- syndetic, though the procedure in the prophase seems to depart from the method described by Gr&GorrE (17) for parasyndesis. According to GREGOIRE, the chromatin in the prophase takes the form of thin paired filaments (leptonema) which fuse (zygonema), shorten and thicken (pachynema), and again separate (strepsinema). In Smilax the chromatin in the prophase is distributed in granules, which are frequently seen in pairs. That which takes place between this condition and the spireme is obscured by synapsis. The con- struction and relative arrangement of the chromosomes in the spireme can be inferred only from subsequent behavior. After synapsis, two longitudinal splits occur; the first appears early in the spireme and can be traced through strepsinema to diakinesis; the second split shows sometimes in the univalent halves of the gemini at diakinesis, but more often not until the metaphase. From this we may infer that the first doubling is a separation of previously paired elements and that the chromosomes or chromatic bodies are placed side by side in the spireme. The second doubling is a genuine fission. Discussion PERSISTENCE OF CHROMOSOMES.—Much of the cytological work of recent years has brought forward directly or indirectly the question of the persistence of chromosomes or of some smaller unit. The rediscovery of the work of MENDEL has given added impetus to the hope of finding a physical basis for heredity or the unit characters of MENDEL which, according to experiment, seem to pass from generation to generation inviolate. Opinions concern- ing the existence of this cytological unit necessarily vary. Some favor the idea of persistent chromosomes; some maintain that 42 BOTANICAL GAZETTE [JANUARY the unit is smaller; while the observations of others imply the non-existence of a persistent chromatin body. The work of OvERTON strongly supports the theory of chromo- some persistence. In the resting somatic nuclei of Thalictrum purpurascens and Calycanthus floridus the chromosomes are repre- sented by definite visible bodies, the prochromosomes (OVERTON 33, 34). From his study of the nuclei in the pollen mother cells of Campanula grandis, Helleborus foetidus, Thalictrum purpurascens, and Calycanthus floridus, he draws the conclusion that the chromo- somes never lose their identity in either somatic or germ nuclei. Even on the spireme the chromosome unit is distinctly visible. During interkineses (OVERTON 35) of somatic mitoses progressive vacuolation and enlargement of the chromosomes take place, but the chromosome outline can always be traced. Larsacu (21) in working on the Cruciferae finds that the chromosomes remain as clearly defined in the resting condition as during mitosis. ROSENBERG (36), in the resting nucleus of the hybrid Drosera longifolia X rotundifolia, finds paired chromatic bodies that equal the number of somatic chromosomes. These he calls prochromo- somes or centers of chromosome formation. Davis (9) described chromatic bodies in the nuclei shortly after the last division in the archesporium of Oenothera gigas, which he thinks probably are chromatin centers or prochromosomes. On the other hand, the theory of nucleolar origin of chromo- somes does not support the view of chromosome permanence. The author has already referred to the work of WAGER (43) and Daruinc (7) describing the budding of chromosomes from the nucleolus. SHEPPARD (38) investigated the behavior of the nucleo- lus in Hyacinthus. In the spireme stage he found the nucleolus apparently being drawn out upon the chromatin threads by means of nucleolar pseudopodia connected with the chromatin threads. Here, as described, the chromatin does not originate entirely from the nucleolus. BERGHs (3) found large nucleoli in the somatic cells of Spirogyra which break up into bodies partly chromatic and partly achromatic equal to the number of chromo- somes. A more detailed citation of this will occur later. Miss Dicpy (11) states that there is no relation between the number of 1914] ELKINS—MATURATION IN SMILAX 43 chromatic aggregations in the resting nucleus of Galtonia candicans and the number of chromosomes; moreover, in the telophase of the somatic divisions the chromosomes lose their identity, their centers dissolving and the chromosomes breaking into small portions. Many cytologists compromise on a middle ground and assume that bodies which are smaller than the chromosomes and into which the chromosome is divisible, are the chromatic units. These have been styled as pangens (MorrieR 29) or chromomeres (ALLEN 1, Lewis 24). In the ordinary use of the above terms the pangen represents a smaller unit than the chromomere; in this connection the terms are used simply to designate a small chromatic body of no determined size. The chromosome represents a definite group of these units and is probably formed for the purpose of facilitat- ing segregation and mitosis. ALLEN figures the actual union of chromatin granules in the spireme, with their subsequent separa- tion. Morrtrer finds no evidence of prochromosomes but supports the theory of the individuality of pangens. Lewis describes gran- ules in the resting nucleus in excess of the number of chromosomes. The differences among the above citations are not as serious as they might seem. By the adoption of a hypothetical unit smaller than the chromosome, it is not difficult to imagine that its ap- pearance, whether alone or in close approximation to its fellows, might vary and vary much with the different species of plants Studied. In the plants studied by Overton and Larsacu the chromosomes may be said to pass from one stage to another always In definite uniform groups, the prochromosomes. We may say these bodies maintain their permanence because of an unchan- ging mutual attraction of the chromomeres in each chromosome. We may conceive of another condition in which the mutual attrac- tion of the chromomeres in each chromosome group varies with the resting and active stages of the nucleus. Although RosEN- BERG (36) found the somatic number of chromatin bodies in the resting nuclei of the hybrid Drosera, he considered them as chro- matin centers about which chromatin units congregated in th Prophase, always with the same relative arrangement. This theory advanced by RosENBERG may be modified and extended to 44 BOTANICAL GAZETTE [JANUARY cover a condition where no chromatin centers are visible, but in which the chromatin units, or small groups of units, arising from the fragmentation of a single chromosome, exert a mutual attrac- tion and come together in a uniform body during the prophases. It is somewhat more difficult to apply this conception to the cases of nucleolar origin of chromosomes. Although little is known about the nature and structure of the nucleolus, it seems plausible that the same relations between chromomeres may exist whether they are inclosed in a comparatively small body, the nucleolus, grouped in several small bodies, the chromosomes, or scattered in the nucleus. An obstacle to the view of the persistence of either chromo- somes or smaller chromatin units arises, however, when we con- sider the recent work of certain authors, such as that of Miss Dicpy (10) on Galtonia candicans, or that of GATES (16) on Oceno- thera gigas. Miss Dicpy describes a condition in Galtonia in which chromatin buds off from the nuclear framework, synaptic knot, or nucleolus, and passes into the cytoplasm or even into ‘neighboring cells; these buds eventually disintegrate. Though Miss DicBy implies that the parent nuclei develop normally, she does not describe their development beyond the spireme stage. However, she cites cases where entire loculi contained aborted pollen mother cells. Gates describes a similar phenomenon in Oenothera gigas. During the synaptic stage there is an extrusion of a part of the chromatic matter of the spireme into an adjoining cell; the extruded portion degenerates, but the nucleus from which it came behaves normally. CARRUTHERS (6), in a description of the cytology of Helvella crispa, states that there are extrusions of chromatin-like material from the poles of the nucleus, which disintegrate in the cytoplasm and take up nucleolar stains. Grices (18) says, of the masses of chromatin in the nuclei of Rhodochytrium, a portion re- mains free and is cast into the cytoplasm or remains as beads on the spindle fibers, while the rest of the chromatin forms the chromosomes. It is also not without interest to recall the condition of Spirogyra (BERGHS 3, MITZKEWITSCH 27) where a chromatic nucleolus dur- ing the anaphase shows tiny chromosomes enveloped in its mass; at the metaphase the nucleolus is divided and the halves move 1914] ELKINS—MATURATION IN SMILAX 45 toward the poles of the spindle where the nucleolar mass is resolved into large chromosomes. Upon decolorization, small portions, the size of the prophasic chromosomes, at the equatorial ends of the large chromosomes strongly retain the stain. The deeply stained portions of the large chromosomes BERGHS considers the ‘“‘chromo- somes veritables.”” In describing the larger bodies the word “chromosome”’ is used merely for convenience. From the observations just noted, we may draw the conclusion that there are substances which are not chromatic in the sense of being the carriers of hereditary qualities, but which at some stages have the same appearance and pass through certain phases in closest proximity to the real chromosome. CARRUTHERS (6) sug- gests that the extruded bodies are masses of nutritive material for which the nucleus has no further use. Conditions in Smilax herbacea do not support the theory of persistence of the chromosome as a physical unit, but of a smaller unit. The number of chromatin bodies in the microspore mother cell exceeds the number of somatic chromosomes ; the same is true of the somatic nuclei of the nucellus. As these chromatin bodies vary in size, we consider that they are aggregates of units or chromomeres; also that the size of the chromomere aggregate varies with the number of units contained in it. Finally, during synapsis the chromomere aggregates form chromosomes according to a law of natural affinity. There is no evidence of a loss of chro- matin or chromatin-like material. PAIRING OF CHROMATIC ELEMENTS.—Closely connected with the theory of the persistence of chromatic units is the theory of the pairing of parental elements throughout the sporophytic phase. Before the theory of permanent, paired chromatic units was advanced, “pairing” was described only in connection with the prophase of the first meiotic division where parallel conjugation (parasynapsis or parasyndesis) of thin chromatic filaments was considered typical. A large group of cytologists now present a dif- ferent mode of conjugation, namely, of the “end to end” type (telosynapsis or metasyndesis). __ The difference between the two methods is not as important as it seems to be. Too much stress has been laid on the comparative 46 BOTANICAL GAZETTE [JANUARY merits of parasyndesis and metasyndesis. Granted that the chromosomes are fully formed, so far as the arrangement of con- stituent parts is concerned, at the time of synapsis, there need be no difference in the ultimate result whether the homologous chromosomes appear in the spireme side by side or one ahead of the other; in either case the paired chromosomes are adjacent and are not prevented by their previous arrangement from exhibiting the same relations from diakinesis through succeeding stages. JORDAN (20) suggests that both parasynapsis and _telosynapsis may occur in the same prophase; that is to say, the “end to end” arrangement of chromosomes in the spireme is frequently followed by a pronounced loop formation, resulting in a parallel approxi- mation of chromosomes. On the other hand, parasynapsis may be followed by fusion of the ends of paired chromosomes (diakine- sis). GATES (15) explains the appearance of both types of con- jugation from a mechanical standpoint. According to his view short chromosomes are particularly adapted to telosynapsis, while long chromosomes are parasynaptic. The extension of the theory of chromosome pairing to cover the entire sporophytic phase is supported by the observations of several investigators. STRASBURGER (39), in a study of the root tips of Piswm, found many cases where the chromosomes were grouped in pairs on the nuclear plate. He concludes that the parental chromosomes in the nuclei of the sporophyte generation do not form two separate groups, but that the homologous chromo- somes occur in definite positions with respect to each other. He also figures a similar condition in an integument cell of the ovule of Lilium Martagon (StRASBURGER 40). Miss SYKES (42) describes a paired arrangement of chromatic elements in the somatic nuclei of Hydrocharis Morsus-ranae and Bryonia dioica. Lychnis dioica and Sagitiaria montevidensis show fully formed chromosomes lying in pairs. OVERTON (34) states that, in the somatic nuclei of plants which he has studied, definite chromatic bodies were visible lying in pairs (Campanula grandis, Helleborus foetidus, Thalictrum pur- purascens, Calycanthus floridus). BONNET (4), however, finds no satisfactory evidence of pairing in the diploid nuclei of the Yucca, although he finds definite chromosomes. 1914] ELKINS—MATURATION IN SMILAX 47 In plants which do not possess the persistent chromosome, the chance of observing the paired arrangement of smaller groups of chromatic units is much lessened. As mentioned early in this paper, the chromomeres or chromomere aggregates in either somatic or germ nuclei of Smilax herbacea frequently appear in pairs or double pairs. This seems to occur too often to be merely a coincidence, yet it could not be determined as a universal condi- tion. THE SEX DETERMINANT IN PLANTS.—Although no reference to the sex determinant has been made in the preceding pages, this study was first attempted with the hope of finding the idiochromo- some in a dioecious plant. Wutson (44), in his studies of the determination of sex in insects, places the decisive sex factor in the sperm. Here he found one-half of the sperms each carrying one or more extra chromosomes or a chromosome unique in size. All cases which cannot be placed in the above groups he relegates to a group where there is no physical variation of the chromosomes in the sperm cells, but where one may presume a physiological variation. Botanists have been unsuccessful in their efforts to find the idiochromosome. Darwinc (7) in working on the sexual cells of Acer Negundo (staminate material) found that one daughter nucleus after the first division contained a secondary chromatin mass; after the second division, two of the granddaughter nuclei each contained one more chromatin mass than the other two. In the resting stage, however, all the nuclei looked alike. To these secondary masses DARLING attached a possible sexual significance. Miss Sykes (42) found the nuclei of both sexes of unisexual plants She had studied (Hydrocharis Morsus-ranae, Bryonia dioica, Lychnis dioica, Mercurialis perennis, Sagittaria montevidensts, Cucurbita Pepo) to be identical in the number and form of the chro- mosomes. STRASBURGER’S (41) efforts to find a structural basis for the determination of sex were rewarded with negative results. On the nuclear reduction plate of Melandryum rubrum he observed a pair of chromosomes much larger than the other gemini; this same condition appeared again on the homotypic spindle. Thus, — one large chromosome was distributed to each of the tetraspores. ‘ 48 BOTANICAL GAZETTE [JANUARY However, he found that, though the four pollen grains of each group usually agreed in size, there were groups in-which two of the pollen grains were larger than the corresponding two. This pos- sible indication of sex differentiation was destroyed when he found a like condition among the pollen grains of hermaphrodite plants (Lychnis Flos-jovis, Silene fimbriata). In Smilax herbacea no trace of an idiochromosome was found. During the metaphase of the first division one frequently found a chromosome pair which anticipated the other gemini in separat- ing and moving toward the poles (figs. 17, 18), but no differences were observed in the homotypic division or in the tetraspores. Moreover, precocious chromosome movement away from the equator during the heterotypic division has been reported by CarviFF (5) in Salomonia, a hermaphrodite: For the present, then, we may assume a physiological differ- ence in the tetraspores of dioecious plants which has no physical manifestation. Summary 1, The nuclei of the young microspore mother cells each con- tain several nucleoli of varying size. The nucleoli fuse during the prophase, forming one large nucleolus at synapsis. During the early prophase the nucleolus is provided with several “papillae.” These doubtless represent small nucleolar bodies which also fuse with the larger nucleoli. The nucleolus usually has at least one papilla until its disappearance at the metaphase. 2. The chromatin in the young microspore mother cell occurs in the form of granules or chromomere aggregates (the chromomere is here considered a chromatic unit). 3. There is no presynaptic reticulum, leptonema, or zygonema. The chromatin granules are held in an indefinite linin mesh. 4. Synapsis is reached by a contraction of the linin-supporting structure drawing the chromatin granules together. : 5. The chromatic elements emerge from synapsis in the form of a spireme which soon becomes double. 6. The spireme shortens and thickens. Transverse segmenta- tion of the spireme results in the formation of long paired chromo- 1914] ELKINS—MATURATION IN SMILAX 49 somes which continue to shorten and thicken, producing the char- acteristic gemini of diakinesis. ’ 7. The separation of homologous chromosomes at the meta- phase proceeds as usual. At this stage the chromosomes frequently show a split preparatory for the second division. 8. At the telophase a nuclear membrane appears. During interkinesis the chromatin is in the form of a band, apparently wound about the periphery of the nucleus. The band seems to be split or slightly vacuolate. 2 9. With the formation of the spindle of the second division the nuclear membrane disappears and the chromatic band resolves into chromosomes. to. At the homotypic metaphase the longitudinal halves of the chromosomes separate. 11. The method of reduction in Smilax herbacea essentially coincides with the “hétérohoméotypique” scheme of GREGOIRE. 12. The persistent chromatic body in Smilax is a smaller unit than the chromosome. 13. The pairing of chromatic bodies was observed in the pro- phase, but not as a universal phenomenon. The same condition was evident in the nuclei of the nucellus. 14. An effort to find a sex determinant in Smilax was futile. The writer wishes to express her indebtedness to Professor A. W. Evans for suggesting this study and for his helpful advice and criticism. Yate University New Haven, Conn. LITERATURE CITED 1. ALLEN, C. E., Nuclear division in the pollen mother cells of Lilium cana- se. Ann. Botany 19:189-258. pls. 6-9. 1905. 3. Bencus, Jutes, La formation des chromosomes hétérotypiques dans la Sporogénése végétale. IV. La Cellule 22:141-160. pls. 1, 2. 1905. » Le noyau et le cinése chez le Spirogyra. La Cellule 23:55-86. bls. 1-3. 1906. 4 Bowner, Jean, Sur le groupement par pairs des chromosomes dans les hoyaux diploides. Archiv. Zellforsch. 7:231-242. pls. 21, 22. 1911. on ” a 25- “ BOTANICAL GAZETTE [JANUARY . CarvirF, Ira D., A study of son and reduction. Bull. Torr. Bot. Club 33: Pt 506. pls. 12-15. . CARRUTHERS, D., Contbtins a ‘the cytology of Helvella crispa. Ann. Botany 25:243- ae: pls. 18, 19: IQII Dar ine, C. A., Sex in pede plavits’ Bull. Torr. Bot. Club 36:177- 199. pls. 12-14. 1909. Davis, B. M., The reduction division of Oenothera biennis. Ann. Botany 24:631-653. AR 52, 53. IQI0. , A comparison of the reduction ae of —— Lamarckiana and O. gigas. Ann. Botany 25:941-974. pls. 71-73. . Dicsy, L., Observations on chromatin bodies and hake velatiod to the nucleolus in Galtonia candicans. Ann. Botany 23:491-502. pls. 33, 34. 1909- , The somatic, premeiotic, and meiotic nuclear divisions of Galtonia candicans. Ann. Botany 24:727-757. pls. 59-63. 1910 Ernst, A., Chromosomenreduktion, Entwickelung des Embryosackes, und Befruchtung bei Paris quadrifolia L. und Trillium grandiflorum Salisb. Flora 91:1-46. pls. 1-6. 1 - Farmer, J. B., and Moorg, J. E. S., New investigations in the reduction phenomena of animals and plants. Proc. Roy. Soc. London 72:104-108. figs. 1-6. 1903. . Gates, R. R., A study of reduction in Oenothera rubrinervis. Bot. GAZ. 46:1-34. pls. 1-3. 1908. , The mode of chromosome reduction. Bor. Gaz. 51:321-344. IQII. , Pollen formation in Oenothera gigas. Ann. Botany 25:909-940- pls. 67-70. 1911. Grécorre, V., Les cinéses de maturation se ms deux regnes. Second Mémoire. La Cellule 26:223-442. figs. 1-145. Grices, R. F., The development and cytology aA Pads cee: Bot. GAZ. 53: ae pls. 11-16. 1912. - GuIGNARD, L., Le développement du pollen et la réduction chromatique dans le Roles major. Archiv. Anat. Micr. 2:455-s09. pls. 19, 20. 1899- Jorpan, H. E., Spermatogenesis of the opossum. Archiv. Zellforsch. 7241-87. pls. pai jigs. 2. 1911. - Latpacu, F., Zur Frage nach der Individualitit der Chromosomen im Pflanzenreich. Beih. Bot. Centralbl. 22": Igt—210. pl. 8. 1907. Lawson, A. A., The phase of the nucleus known as synapsis. Trans. Roy. Soc. Edinburgh 47:591-604. pls. r, 2. 1911. , Nuclear osmosis as a factor in mitosis. Trans. Roy. Soc. Edin- burgh 48: 137-161. pls. 1-4 IQII . Lewss, I: M., The behave of thé chromosomes in Pinus and Thuja. Ann. Botany 22: ag Paw pls. 29, 30. 1908. McCtune, C. E., The chromosome soaniphise of orthopteran spermato- cytes. Biol. Bull. 9: hom figs. 21. 1905. 1914] ELKINS—MATURATION IN SMILAX 51 26. 44. 45. Martins Mano, T., Nucléole et chromosomes dans le méristéme radicu- laire de i tuberosum et Phaseolus vulgaris. La Cellule 22:57-77. pl. 4 5 eeeirerien: L., Uber die Kerntheilung bei Spirogyra. Flora 85:81- 124. pl. 5. 18098. . Miyake, K., Uber Reduktionsteilung in den Pollenmutterzellen einiger 1906. Motiokotylen. Jahrb. Wiss. Bot. 42:83-120. pls. 3-5. - Mortier, D. M., The development of the see Be, chromosomes in pollen mother cells. Ann. Botany 21:209-349. pls. 27, 28. 1907. . NEmec, B., Das Problem der Befruchtungsvorginge und andere zyto- hoitoche Prawn. Berlin. 1910. - Nicuots, G. E., A a study of Juniperus communis var. depressa. Beih. Bot. Centralbl. 25:201-241. pls. 8-17. figs. 4. 1910. - Nicuots, M. L., The development of the ge of Sarracenia. Bor. Gaz, 45:31-37. pl. 5. 1908. - OvERTON, J. B., Uber Reduktionsteilung in den arcsec einiger Dikotylen. Salat. Wiss. Bot. 42:121-153. pls. 6, 7. 190 , Organization of nuclei in pollen mother cells. ae Bolatiy 23:19- 61. pls. 1-3. ibe organization and reconstruction of . pe in the root tips of Podophyllam peltatum. Science 33:193, 104. - RosenBerc, O., Cytologische und Morphologische Studien an Dros lonieliax rotundifolia Kgl. Svensk. Vetensk. Akad. Handl. —64. pls. I— . ay i H., The cea of the macrospore nucleus. Bor. Gaz. 23:430-452. pls. 37-30. SHEPPARD, E. ts The ‘ieee of the nucleolus in mitosis. Jour. Roy. Micros. Soc. 1909: 551-554. - STRAsBURGER, E., Uber die Individualitit der Chromosomen und die Pintigittas race Jahrb. Wiss. Bot. 44:482-555. pls. 5-7. fig. I. a » Chromosomenzahlen, Plasmastrukturen, pee cages und tidettcnsietiine. Jahrb. Wiss. Bot. 45:479-570. pls. 1-3. ————, Uber geschlechtsbestimmende Ursachen. Jahrb. Wise, Bot. 48:427-510. pls. 9, ro. IQIo. SyKEs, M. G., Note on the nuclei of some unisexual plants. Ann. Botany 23°340-343. I909. - Wacrr, H., The nucleolus and aap ita in the root apex of Phase- olus. Ann. Botany 18: 30-55. pl. 5. Wison, E. B., Recent researches on he determination and heredity of Sex Science aa cp 5y6, 1909. et, S., Sporogenesis in Nephrodium. Bor. Gaz. 45:1-30. pls. 4. 1908, 52 BOTANICAL GAZETTE [JANUARY EXPLANATION OF PLATES IV-VI Microspore mother cells Fics. 1 and 2.—Young spore mother cell; nucleoli fusing; X 2400. IG. 3.—Same as fig. 1; nucleolar “papillae”; 2400 Fic. 4.—Young spore mother cell; paired chromatin bodies; 2400 Fic. 5.—Spore mother cell with one papillate nucleolus; promote bodies in pairs; XX 2400. Fic. 6.—Early synapsis; 1725. Fic. 7. —Synapsis; X1725. Fics. 8, 9.—Late synapsis; X1725. Fic. 10.—Spireme; 172 Fic. 11.—Early spireme aa X 2400. Fic. 12.—Spireme; X 2400 Fic. 13.—Late spireme; beginning of transverse segmentation of spireme; Fic. 14.—Strepsinema; X 2400. Fic. 14¢.—Pair of homologous chromosomes; same stage as fig. 14; Fic. 15.—Diakinesis; X 2400. Fics. 16-18.—Metaphase; X 2400. Fic. 19.—Late anaphase; X 2400. Fic. 20.—Interkinesis; X 2400. Fics. 21-26.—Homotypic phases. IG. 21.—Prophase; 1725. Fic. 22.—Late prophase; 172 a _ Fic. 25.—Metaphase; polar view of equatorial plate; 1725. Fic. 26.—Late anaphase; XX 2400 Fic. 27.—Nucleus from somatic cell of young ovule; X 2400. Megaspore mother cells Fic. 28.—Early spireme stage; X 2400, Fic. 29.—Spireme; X 2400 Fic. 30.—Spireme; later. uae than fig. 29; 2400 Fic. 31.—Strepsinema; X 2400. Fics. 32, 33.—Diakinesis; 2400. PLATE IV BOTANICAL GAZETTE, LVII ELKINS on SMILAX BOTANICAL GAZETTE, LVII PLATE V ELKINS on SMILAX PLATE VI BOTANICAL GAZETTE, LVII ELKINS on SMILAX COMPARATIVE HISTOLOGY OF ALFALFA AND CLOVERS KATE BARBER WINTON (WITH EIGHT FIGURES) Perennial leguminous forage plants are growing in importance both for green feeding and for hay, and some of them, notably alfalfa, red and alsike clovers, are well adapted for grinding into meal. The work detailed in this paper was undertaken to facilitate the microscopic identification of the species named in mixed cattle foods. The highest feeding value of the hay or ‘“‘meal’’ is obtained from plants cut in early flower, though the more or less mature fruits and seeds are not infrequently found in the products on the market, especially in alfalfa meal. Alfalfa Alfalfa (Medica sativa [L.] Mill., Medicago sativa L.) is a native of Asia and has been cultivated for fodder since long before the Christian era. It is now grown in both hemispheres, especially in the arid and semiarid regions of the Southwest, for use either fresh or dried. As the hay is brittle, resulting, when fed from the bale, in a considerable loss of leaves, the product is often kiln- dried and ground to a meal. Ordinary alfalfa, or lucerne, branches profusely and bears Fic. 1.—Alfalfa (Medica setiva): I, alternate leaves (fig. 1, I) con- ‘eal, Xt; 11, flower, X3; 11, seed, een rey Mas 2, tet, Xs. sisting of three distinct obovate to lanceolate leaflets finely dentate at the apex. The plant is described as glabrous; hairs, however, are evident under a lens and are highly characteristic with higher magnifications. The flowers (fig. 1, IZ) appear in racemes of 8-25 each and wither after flowering. They are of the distinctly papilionaceous type, small (8-10 mm. in length), 53] [Botanical Gazette, vol. 57 54 Sante BOTANICAL GAZETTE [JANUARY and delicate in structure. The hairy calyx consists of a tube and 5 teeth-like lobes of about the same length as the tube, at the base of which is inserted the violet-colored corolla. The 1o stamens are combined in two sets; the ovary is one-celled with several ovules. At maturity the brown pods (fig. 1, ZV) are coiled 2-4 times in close spirals, the diameter of the coil being about 4 mm. . The greenish-brown seeds (fig. 1, 7/7), up to 3 mm. in length, are somewhat kidney-shaped. Many varieties of alfalfa, less widely grown, vary in flower color, through blue, white, and green, to yellow, and in number of pod coils, seeds, and leaflets. -HISTOLOGY Stem (fig. 2).—The epidermal cells (ep) are several times longer than broad and arranged end to end in longitudinal rows inter- rupted frequently by stomata and their accompanying cells. The outer and inner walls are slightly thickened, the former having a cuticle with delicate striations evident in cleared preparations. Bast.—Several layers of . simple thin-walled chlorophyll- hot 2. fae aie cement = in bearing parenchyma cells, inter- Pveodber 5 Pe mciepestt ie ae rupted occasionally, especially vessels; Xx60 at the angles of the stem, by masses of collenchyma, form the outer tissues. Underlying this is a single layer of thin-walled crystal-bearing cells inclosing a zone of bast fiber bundles, each bundle being wedge-shaped in cross section. The individual fibers (f*) are greatly elongated and have walls so strongly thickened that the lumen is often but a mere line. Phloem.—This consists of a characterless mass of —— cambium cells and sieve tubes. Xylem.—The most evident elements of this woody tissue are the pitted (ta) and spiral (sp) vessels and the pitted wood fibers (/?)- 1914] WINTON—ALFALFA AND CLOVERS 55 Pith—This consists of comparatively large, thin-walled, pitted cells with no cell contents. Lear.—U pper epidermis ——The cells are approximately 35” in diameter, although often elongated, especially over the veins. The cell walls are strikingly sinuous and of uniform thickness. Numerous simple stomata are scattered over the whole surface, and occasional hairs, similar to those so abundant on the lower _ surface, occur at the base of the leaf. Cuticular striations are very distinct in cleared material. The palisade layer consists of very simple cells with breadth half the height. Mesophyll.—The ground tissue of this layer is made up of a loose mass of parenchyma with no char- acteristic features; accompanying the simple bundles, however, are crystal-bearing cells (fig. 3, cr) of diagnostic importance. The latter are thin-walled and arranged more or less end to end in longitudinal rows. Each cell contains a single “<5 monoclinic crystal about 18m in Fic. 3.—Alfalfa: lower epidermis length, the facets of which often of leaf with unicellular hair (*), capi- appear corroded. tate hair (f), and stoma (s/o); cr, Tie lowes -cosdermis ie crystal cells accompanying bundles; differs from the upper principally in the greater number of hairs which are scattered over the whole surface and margin of the leaf, being especially numerous along the veins. The cells surrounding the hair base form a rosette. The hairs are of two kinds, unicellular (numerous) ard capitate (scat- tered). The unicellular hairs (#) are more or less sinuous, thick- walled, the lumen being a mere line, with small but prominent warts distributed over the entire length. They arise from a small, slightly thick-walled basal cell and average 800 w in length and 15 # in breadth, though the length varies up to over 1.5 mm. The 56 BOTANICAL GAZETTE [JANUARY capitate hairs (#) consist of a stalk of two or three cells and a multicellular head, all the cells being thin-walled and frequently collapsed. Catyx.—The epidermis bears unicellular and capitate hairs of the same general structure as those on the leaf. On the calyx tube the unicellular hairs are comparatively short and_ thick-walled, while on the lobes they are longer and thinner-walled, with corre- spondingly broader lumen. The simple bundle running out to the tip of each lobe is surrounded by a layer of crystal cells each con- taining a crystal averaging 18 p in length. CoroLta.—The epidermal cells of the petals, at the base, are very thin-walled, elongated, and some- what sinuous, and bear toward the tip papillae with striated cuticle. The bundles are very small, often but a single spiral vessel marking their course. STAMENS.—The filaments con- sist of delicate cells similar to those of the petal in structure. The anthers have riblike thickenings Fic. 4.—Alfalfa: elements of pod Over their whole surface. in surface view; aep, outer epidermis Pistit.—The stigma bears with hair scar (x); iep, inner epi- : d Gutcaisy of ayiul aye ¥. eben: colorless papillae closely matte X 160. together. The style is made up of small characterless cells except the outer half, which is covered with cells slightly thickened, apparently for mechanical support. Ovary.—The small thin-walled epidermal cells bear numerous thin-walled unicellular and capitate hairs. PERICARP (fig. 4).—The epicarp (aep) consists of a single layer of empty cells usually more or less elongated except at the stomata, about which they form a rosette. Hairs are frequently present, but often break off from the dried pod, leaving a scar («) with a thickened wall. Mesocarp.—The characteristic tissues are: crystal cells (cr) 1914] WINTON—ALFALFA AND CLOVERS 57 with very thin walls, frequently side by side in rows, each cell containing a single crystal, and fibers (f) with rather blunt ends and pitted walls, the number of pits being most numerous in fibers with the thickest walls. Endocarp (iep).—A single layer of epidermal cells without stomata completes the pericarp. SPERMODERM (fig. 5, S; fig. 6).—The palisade cells (pal) are upward of 35 uw high and 8-10 uw broad, with rounded outer ends and a thin cuticle. A narrow light line (J), situated about 7 u within the outer end, can be easily seen in cross section. As is 3) c.ge? Fic. 5.—Alfalfa: seed in cross Fic. 6.—Alfalfa: elements of seed in section; S, spermoderm consists of _ surface view; pal", outer palisade cells; pal?, palisade cells (pal) with cuticle (cut) inner palisade cells; sub, subepidermal layer and light line (J), subepidermal layer _(hour-glass cells), and ", p*, parenchyma of (hour-glass cells) (sub), and paren- spermoderm; ep, epidermis, and , paren- chyma (~); E, endosperm; C, coty- chyma of endosperm; X 160. ledon with epidermis (e p) and aleurone grains (al); 160, “ usual in legumes, the outer cell walls are greatly thickened, showing a radiating cavity (pal*) in surface view, while the inner portion of the cells has thinner walls and correspondingly broader lumen (pal?). Subepidermal cells (sub).—These cells, although only about 6 uw high over the greater part of the seed, are very broad (upward of 304) and are especially striking because of their prominent ribs clearly evident in surface view, where they present a beautiful radiating effect. In cross section they show evidence of the hour- glass form so characteristic of many legumes, the inner ends being broader than the outer. 58 BOTANICAL GAZETTE [JANUARY The parenchyma (p) consists of several layers of compressed cells. The outer layers are of simple thin-walled parenchyma without intercellular spaces (~"), while the inner layers are often distinctly spongy with evident intercellular spaces (9°). ENpDOSPERM (fig. 5, E; fig. 6).—A simple epidermal layer (e?) containing aleurone grains is followed by several layers of large, more or less collapsed, empty cells with thin walls ($3). Emprvo (fig. 5, C).—The cotyledons have a small-celled epi- dermis and mesophyll containing aleurone grains (a/) but no starch. Palisade cells underlie the inner epidermis. Red clover Red clover (Trifolium pratense L.) is indigenous to Europe and is extensively grown for fodder in the United States, where it also grows spontaneously, having escaped from cultivation. The pubescent stems are ascending, with 3-foliate toothed leaves, each oval leaflet often being notched at the apex and marked on the upper surface with a whitish spot. The rose-red flowers are borne in a dense sessile head closely surrounded by the upper- most leaves. The persistent calyx, with 5 bristle-like teeth and a bearded ring in the throat, is nearly as long as the delicate papilio- naceous corolla, which is tubular below and withers after flowering. The pod differs from alfalfa in that it is one-seeded, straight, and flattened oval, with a very thin membranous lower half and hard caplike top. The seeds are slightly smaller than those of alfalfa, averaging 2 mm. in length. They are flattened kidney-shaped or rounded triangular with unequal sides one of which is concave. The color varies through light yellow to purple, the individual seeds being uniform in color or variegated. HIsToLocy SteM.—The epidermal cells are longitudinally elongated with straight walls, often beaded especially just below the nodes, and a striated cuticle. Interspersed among these cells are numerous stomata and both unicellular and capitate hairs. The unicellular hairs, like those on the leaf, are long, thick-walled, warty, and 1914] WINTON—ALFALFA AND CLOVERS 59 borne on a characteristic swelling of the epidermis having the appearance of an emergence. Bast.—The only noteworthy tissues are the crystal-bearing cells accompanying the bundles of bast fibers and the large air spaces, below the unicellular hairs, such as occur on the leaf. Phloem, xylem, and pith are similar to those of alfalfa. Lrear.—The upper epidermis consists of approximately isodia- metric cells with thin, gently wavy walls and scattered stomata. Hairs are absent. Mesophyll—The small bundles running through the simple parenchymatous ground tissue are accompanied by crystal-bearing cells, each cell containing a monoclinic crystal averaging 16 w in length. The lower epidermal cells (fig. 7) have sinuous walls, the rather sharp bend of the waves being thickened and sometimes extended into the cell cavity as projections. Highly characteristic are the hornlike projections about _ : the stomata (sto). The walls Fic. 7. oe (Trifolium thas become slightly thicker and es line « remind Sa ° usually pitted toward the capitate hair; sfo, stoma; 160 base of the leaf, especially over the veins. As on the stem, there are two forms of hairs, unicellular and capitate. The unicellular hairs (f) are stiff, very thick-walled and warty, varying in length up to 2 mm. and in diameter up to 30. The warts are rather more prominent than on the corresponding hairs of alfalfa. They arise from a conical Tosette of elongated cells over a large intercellular space, resembling in outward appearance an emergence. The capitate hairs (?), € those on alfalfa, consist of a stalk formed of a few cells in a single row and a club-shaped multicellular head. ALYX.—The outer epidermis consists of simple cells with occa- sional wavy walls and numerous hairs both unicellular and capitate, 60 BOTANICAL GAZETTE [JANUARY similar to those on the leaves and stem. The bristles, with papillae the whole length, end with a tuft of stiff unicellular hairs. Mesophyll.—A single layer of crystal-bearing cells is conspicuous. The inner epidermis is made up of wavy-walled cells and occa- sional hairs. Corotta.—The epidermal cells have very thin walls with papil- lae and striated cuticle toward the tip. PERICARP.—The epicarp consists of sinuous-walled cells with scattered stomata. On the stem end the cell walls are thin, chan- ging abruptly toward the tip to greatly sae sclerenchyma- tized and pitted walls. The mesocarp cells are inconspicuous, with the exception of occasional scattered crystal-bearing cells. SPERMODERM.—The palisade cells average 45 uw in height (run- ning up to 55m over the radicle) and 7 uw in breadth. A narrow light line lies about 7 » below the thin cuticle. They differ from the corresponding cells of alfalfa in that they are higher and the outer ends are flattened. The subepidermal cells vary in height, but average 10 p. They are upward of 20 uv broad and constricted in the center with lower ends broader than outer. The parenchyma consists of thin-walled collapsed cells. € ENDOSPERM and EMBRYO are of simple structure of no diagnostic importance. Alsike clover Alsike clover (Trifolium hybridum L.), although indigenous to Europe, has become very common in America. The plant branches, with erect stems bearing 3-foliate toothed leaves on long petioles and pedicellate flowers forming a loose round head on a long peduncle. Like alfalfa, the plant is described as smooth, though hairs are evident under a lens and are of diagnostic importance with higher magnifications. The membranous 5-cleft calyx is much shorter than the delicate rose-pink tubular corolla, which after flowering becomes brown and withering-persistent. The pod differs from that of alfalfa in that it is straight and from red clover in that it is 2-4-seeded. The greenish brown seeds are smaller 1914] WINTON—ALFALFA AND CLOVERS 61 than those of alfalfa and red clover, reaching a length of 1.5 mm., but in shape resemble closely those of red clover. They are flattened rounded triangular with one concave side. HISTOLOGY StEM.—The epidermal cells are thin-walled, pitted, and longi- tudinally elongated, with numerous stomata. The cuticle shows longitudinal striations. Occasional hairs both unicellular and capitate are present, the warts usually being indistinct. Bast.—Conspicuous crystal cells are found in the bast just below the chlorophyll-bearing cells. EAF.—The upper epidermis consists of isodiametric cells, avera- ging 30 w in diameter, with straight thin walls. In the mesophyll the cells accompanying the bundles contain crystals averaging 15 u in length. Lower epidermis (fig. 8)—The cells are similar to those of the upper surface, the walls toward Fic. 8.—Alsike clover (Trifolium the leaf margins becoming gently Aybridum): lower epidermis of leat wavy. Occasional unicellular (#) With unicellular hair (?), capitate woe : 5 (#), and stoma (sto); X160. and capitate (#) hairs are present, e former being indistinctly warty and arising from a slightly thickened epidermal cell. They vary in length up to 800 p. Catyx.—The outer and inner epidermis, with sinuous walls, bear capitate hairs similar to those on the leaf, also, at the base of the lobes and along their margins, unicellular thick-walled hairs with occasional indistinct warts. Corotta.—The epidermis consists of elongated sinuous-walled cells with striated cuticle, papillae being present at the tip of the petals _ Pericarp.—The epicarp consists of transversely elongated slightly sinuous thin-walled cells, scattered stomata, and, especially at the margins, capitate hairs. 62 BOTANICAL GAZETTE [JANUARY The mesocarp is but a few cells thick, except at the margins. Scattered crystal-bearing cells occur either singly or in groups. The endocarp is made up of a single layer of thin-walled elon- gated cells. SPERMODERM.—The palisade cells are 30-50 uw in height and 7p in diameter, with a narrow light line about 7» from the outer end. They differ from the palisade cells of alfalfa in that they are slightly higher, and from those of red clover in that they are rounded (not flattened) on the outer ends. The subepidermal cells are not distinguishable from those of alfalfa and red clover. The parenchyma consists of thin-walled collapsed cells. The ENDOSPERM and EMBRYO are of simple structure of no diagnostic importance. Identification in ground material In a coarsely ground product, fragments of the leaves, flowers, pods, and seeds may be picked out and identified, but when pow- dered the unicellular hairs and crystals are the most conspicuous Alfalfa Red clover Alsike clover Lower epidermis of | Wavy walls Deeply sinuous Straight walls nen Papa walls with pr jections at angles and about mata Unicellular hairs... .. Average diameter | Average diameter | Average diameter , warts 30 #, warts 13 #, warts indis- prominent prominent, aris- ing from epider- mal swelling elements. Red clover may be distinguished from alfalfa and alsike clover by its larger, stiffer, and more numerous unicellular hairs arising from a swelling of the epidermis; alsike clover, from alfalfa and red clover, by the less distinct warts on the unicellular hairs. The cell walls of the lower epidermis of the leaf are also char- acteristic, those of alsike clover being straight, of alfalfa simply 1914] WINTON—ALFALFA AND CLOVERS 63 wavy, and of red clover very sinuous with projections at the angles and about the stomata. A scheme for the identification of these three legumes by means of the epidermal cells of the leaf and the unicellular hairs is given in tabular form on the preceding page. The palisade cells of the seed in alfalfa are not over 35 uw high, whereas in alsike and red clover they average somewhat higher. In red clover the outer ends of these cells are flattened, but in alfalfa and in alsike clover they are rounded. Cuicaco, Itt. THE ROLE OF OXYGEN IN GERMINATION CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 181 CHARLES Ac SHULL A study of the respiration of Xanthium seeds was undertaken some time ago with the purpose of determining whether there was any change in the permeability of the seed coats to oxygen during the period following the normal ripening of the seeds. Some evidence was noted previously’ that there was either a change in permeability of the seed coat, or a change in oxygen need of the embryo during the early winter, and it was believed that a careful measurement of the oxygen used by the seeds with coats on and off at successive intervals during the year would show which of these changes occurred, and at what period of the ripening process. Circumstances have prevented the carrying out of this series of tests; but the preliminary results are of sufficient interest in con- nection with the rdle of oxygen in germination behavior to warrant placing the data on record. The measurements were made with a respirometer of excellent type designed by Dr. WitL1AM CROCKER, to whom I am further indebted for suggestions regarding the problem. The respirometer was kept in a Freas thermostat at 25.25 C., and the volumes of oxygen used are reduced to standard conditions. Seeds of X. glabratwm in dry storage for nine months were used. First it was necessary to know what part of the oxygen was used by the coats under ordinary atmospheric germinative con- ditions. Two lower seeds were placed in one chamber of the respirometer, and the coats of two lowers in the other chamber. In 22.5 hours the two seeds used 0.475 cc. of oxygen, while the two coats used 07098 cc. From the results of BECQUEREL’s work* I had suggested that the coats were probably responsible for a part *Sautt, Cuas..A., The oxygen minimum and the germination of Xanthium seeds. Bort. Gaz. 52:453-477. IgII. ? BECQUEREL, Paut, Recherches sur la vie latente des graines. Ann. Sci. Nat. Bot. IX. 5:193-320. 1907. Botanical Gazette, vol. 57] [64 1914] SHULL—GERMINATION 65 of the respiration of intact seeds. That part is now shown to be considerable, amounting in this instance to 20 per cent of the total. The respiration of lower and upper seeds with coats intact under atmospheric conditions of germination was compared, with the result that two lowers used 0.687 cc. and the two uppers 0.509 cc. of oxygen in 42.3 hours, a ratio of lowers to uppers of 1.35:1. It should be said that upper seeds always weigh less on the average than the lowers; and in using equal numbers of seeds the weight of respiring substance is somewhat less in the uppers. The respiration of the lowers with coats on and coats off in ordinary atmosphere is especially interesting (see table I). TABLE I OXYGEN USED TIME Ratio Coats off Coats on 10 hours... ... ©. 500 Cc. 0.3615 cc. 1. 38:1 10-15 ee. 0.478 “ 0.1025 “ 4.65:1 J! ST See ae 0.316 * 0.040 “ 7-9 +1 SAG os 1.294 “ 0.504 “ 2.57 :1 TABLE II OxYGEN USED Tme : “Ratio Coats off Coats on 7 OM ©. 1609 cc. 0.075 CC. 2.1471 oy SER naa ea 0.618 “ 8, i107 * 5.58:1 Total, 17.25 hours. . . 0.9825 “ 0.1947 “ 5.046:1 A similar test with uppers is shown in table II. The coats were not placed in the chambers with the embryos where coats were off, so that the ratios in the tables are too low as regards actual embryo respiration. The rapid increase of use of oxygen by naked embryos as germination commences is well illustrated. Finally, the oxygen used by uppers and lowers with coats on, in an atmosphere 96 per cent oxygen, was compared, with significant -Tesults. Two lower seeds used 1. 007 CC. in 12.5 hours, while the 66 BOTANICAL GAZETTE [JANUARY uppers used but 0.4406 cc., a ratio of 2.28:1. A repetition of this experiment resulted in the lowers using 1.257 cc. in 22 hours, the uppers 0.772 cc., a ratio of 1.63:1. Invisible defects in coats might cause some variation in these ratios, but they are believed to approximate average results. It is interesting to note that two lowers in atmosphere used 2.687 cc. of oxygen in 42.3 hours, while the same number used 1.007 cc. in 12.5 hours in 96 per cent oxygen; and that uppers which used 0.509 cc. in 42.3 hours used 0.4406 cc. in 12.5 hours in 96 per cent oxygen. The increased oxygen pressure causes a large increase in the oxygen intake of both seeds with coats intact, but exerts the greater influence on the lowers. The relation between oxygen influence and respiration seems to be close. At least we may say that the conditions of the oxygen supply which lead to increased use of oxygen are just the conditions which bring about germination. The possibility that oxygen exerts its stimu- lative effect on germination by increasing respiration, thereby yielding more energy, is strongly suggested, without, however, precluding the possibility that other effects correlated with increased respiration might determine its influence in germination. BECKER’ recently tested-the influence of oxygen on the germi- nation of seeds of several plants. The fruits of Dimorphotheca pluvialis were found to germinate more readily in O, than in air, the ray seeds especially showing the favorable influence. Short exposures to oxygen (15 hours) had no such effect, but if the time of exposure were lengthened to 30 hours, this exposure favored further germination under atmospheric conditions. The ray seeds again showed the effect more strongly than the disk seeds. When the fruit and seed coats were removed, 10 hours’ exposure to oxygen affected germination favorably, but 13 hours’ lengthened the germination time. The seeds of Calendula eriocarpa with coats intact were greatly favored by oxygen, while the yellow-brown vertical fruits of Atriplex hortensis and A. nitens showed an injurious effect from increased oxygen pressures. The relation of oxygen to germination in these cases seems to be irregular and inconstant. Becker, H., Uber die Keimung verschiedenartiger Friichte und Samen bei derselben Species. Beih. Bot. Centralbl. 29':21-143. 1912. 1914] SHULL—GERMINATION 67 BECKER draws a general conclusion from his results that oxygen acts as a stimulus, and takes particular exception to the idea advanced by Crocker‘ that the oxygen increases the respiration and in this way initiates germination. In reviewing BECKER’Ss paper,’ I stated that there was no doubt that in Xanthium the oxygen was actually used in germination, and suggested that increased respiration might be identical with BECKER’s stimulus. While it is entirely possible that the oxygen influence is exerted through some other process correlated with increased respiration, the data presented here give the ground upon which that sugges- tion was based. Unfortunately, BECKER’s work gives us no data as to the respiration behavior of the seeds on which he worked, so that no comparison with the behavior of Xanthiwm seeds can be made at present. LEHMANN,’ in discussing the possibility that O, might act as a catalyst, accepts BECKER’s idea that oxygen acts as a chemical - stimulus, not merely by increasing respiration. Of course, the word “stimulus” is vague and indefinite. But it should not imply an additional absorption of oxygen, for this could not occur without involving oxidation of some kind, which would be respira- tion. Even if oxygen is conceived to be a catalyser, that concep- tion does not involve increased use of O,, for catalysts are not used in the processes they carry on. The biological réle of oxygen is so complex that we may not say its effect is always due to increasing respiration or oxidation. The rile, indeed, may be different in different seeds and plants. For instance, Arpdp PaXt’ claims that reduction of oxygen pres- sure even to o. 75 normal lengthens geo-presentation and geo- reaction time to a marked degree. This work of Padv’s still awaits confirmation. And although the earlier work of SticH, JOHANNSEN, and others indicates that this amount of reduction ‘CROCKER, Wa., The réle of seed coats in delayed germination. Bor. Gaz. 42:265-291. 1906, mE § Bor. Gaz. 54:433. 1912. * LEHMANN, E., und OrrenwAtper, A., Uber katalytische Wirkung des Lichtes bei der Keimung lichtempfindlicher — -_— Bot.*5: 337-3%- inal 7 Pat, Arpho, Analyse des a ee ung. Jahrb. Wiss. Bot. so: 1-20, 1grt. deck 68 BOTANICAL GAZETTE [JANUARY should not affect the rate and nature of respiration, yet it would be very desirable to repeat Padt’s work, studying the rate of respiration along with presentation time and reaction time to discover whether there is a parallel effect with that on the res- piration rate and germination power of seeds. ZALESK® has noted the influence of oxygen on the rate of protein synthesis. IvanorF? has shown that oxygen is necessary for the transformation of zymogen into zymase, and, as is well known, there are a number of oxygen carriers and oxygen absorbers in the living cell. Xanthophyll and other pigments absorb oxygen, lecithin plays a similar réle, and PaLLApIN® has now shown that his respiratory chromogens take up oxygen readily. All of these facts go to show how complex the oxygen réle may be, and suggest some of the possibilities of even brief exposure of seeds to oxygen. On the other hand, however, it would be strange if the oxygen effect in some cases were not due simply to its influence upon respiration. The influence of the amount of oxygen present on aerobic and anaerobic respiration, which differ so markedly in the amount of energy released, is well known. Anaerobic may change over to aerobic on access of oxygen, with a consequent rapid rise in energy releasal leading to germination. With these Xanthium seeds it has been shown that when the oxygen supply is increased, it in some way brings about an imme- diate and rapid increase in the rate of oxygen absorption. At the same time, the increased oxygen supply brings about an immediate germination of the seeds. The two effects, increased absorption and germination, are closely correlated as regards their relation to the oxygen supply. This shows conclusively, I believe, that the assumption made by BECKER and LEHMANN, which led them to reject the idea that the influence was exerted through increased respiration, is not correct, so far as Xanthium is concerned. Nor does their work throw any light on this particular point, since they LESKI, W., Zur kenntnis der Stoffwechselprocesse in reifenden Samen. Beih. Bot. Centralbl. 27:63-82. 1911. *IvanorF, L., Uber die sogenannte Atmung der zerriebenen Samen. Ber- Deutsch. Bot. Gesells. 29:563-570. 1911. © Pattapin, W., and Torstaya, Z., Uber die Sauerstoffabsorption durch die Atmungschromogene der Pflanzen. Biochem. Zeitschr. 51:381-397. 1913- 1914] SHULL—GERMINATION 69 did not measure the respiration of the seeds on which they worked. However, owing to the complexity of the oxygen réle in physio- logical processes, it is very difficult to say just which function or functions are affected. It seems certain that the oxygen acts as a limiting factor on some function, whether by limiting the process of respiration or energy releasal, by limiting enzyme formation or the action of oxygen carriers, or in other still less definite ways. The exact method by which absence of oxygen delays germination can be determined only by further investigation. In the mean- time theories may well await the facts which will make philoxephice| discussion of this question unnecessary. UNIVERSITY oF KANSAS LAWRENCE, Kan. BRIEFER ARTICLES A METHOD OF HANDLING MATERIAL TO BE IMBEDDED N PARAFFINE (WITH ONE FIGURE) The usual method of handling material to be imbedded in paraftine is slow and tedious, and attended with some danger of damage to the material. Ordinarily, each batch is killed in a separate bottle, in which it remains up to and even through the paraffine bath. In washing, a cloth is usually tied over the end of the bottle, which is put under a running tap or thrown into a vessel of running water. Either way results in washing of questionable thoroughness. Then the various grades of alcohols and xylols are pipetted on and off, a very tedious process with small light objects that are likely to be drawn into the pipette and injured or lost. After trying several devices, the writer has had success in eliminating these difficulties by the following method: About 6.25 cm. lengths are cut from ordinary medium thickness glass tubing of the desired diameter. One end is heated and slightly flared. Over the flared end is tightly tied a piece of thin cloth, and the excess of cloth and string closely trimme away (fig. 1, A). With a stout cord, a slip knot (B) is quickly tied and drawn up, and holds the cloth firmly. The material is placed in this cloth-bottom tube, and remains in it through all the processes up to the paraffine bath. If the objects are large or numerous, it is better to kill in an ordinary bottle and transfer to the tube just before washing. In washing, the tube of material is placed in a vessel of less height (such as a small salt mouth bottle), and water siphoned into the tube from a supply vessel directly under the running tap (C). The tube end of the siphon is drawn out fine, allowing only a small amount of water to pass over. A section of rubber tubing in the siphon gives greatet flexibility. Because the water level is high in the tube, and all the fresh water flows over the material, washing is very thorough. Under all con- ditions the stream of water is uniform and gentle, even with considerable variation in tap pressure, as we have in Allahabad. Any number of tubes, each with a separate siphon, may be grouped around the supply vessel and washed at one time. Botanical Gazette, vol. 57] [70 1914] BRIEFER ARTICLES 71 The series of alcohols and xylols is prepared in tightly stoppered bottles and arranged in sequence. The tubes of washed material are placed in the bottle of lowest grade alcohol and transferred at proper intervals from bottle to bottle through the series. Any number of tubes are easily and rapidly handled by means of a pair of forceps. There is no danger of losing small objects, because the top of the tube is always Fic. 1.—Sectional diagrams: A, end of tube flared and covered with cloth; B, rapid method of tying cord; C , arrangement for washing material; water flows from the tap into the supply vessel (s), through the siphon into the tube of material (¢), through the cloth bottom, and overflows from the small vessel; a piece of rubber tubing (r) in the siphon adds flexibility. above the level of the reagent. With proper labels on the series bottles, the exact location of the material, and the next change, are always known at a glance. The material is left in the tubes through all the Processes up to the first bath in melted paraffine. _ _ The advantages of this method are as follows: there is no loss of time in handling large quantities of small light objects; washing is easy and thorough; there is no danger of injury to the most delicate material; no 72 BOTANICAL GAZETTE [JANUARY labels, except those for identification, are necessary on the separate batches of material; and the series of alcohols and xylols may be used repeatedly, for while there is a continual weakening of each grade in the series, the weakening is proportional throughout the whole series, so that their relation to each other remains practically unchanged.—WINFIELD DupcEon, Ewing Christian College, Allahabad, India. THE RELATION BETWEEN THE TRANSPIRATION STREAM AND THE ABSORPTION OF SALTS During the winter of 1908-1909 experiments were conducted at Santiago de las Vegas, Cuba, in order to determine the comparative transpiration of tobacco plants under cheesecloth shade and in the open ground. For this purpose plants were grown in galvanized iron tanks which were set into outer incasing tanks permanently sunk in the ground. Six tanks were placed among the plants of a field of tobacco grown under cheesecloth, and six were set in an adjoining tobacco field not shaded. The quantity of water transpired by the plants in the tanks was deter- mined by daily weighings, the quantity transpired being replaced each day. At maturity the leaves, stems, and roots of each plant were harvested separately, dried, and ground. The ash was determined in water-free samples of the ground material. From the data the total ash of the plants was calculated. The condensed results of the experiment are given in the following table. PLANTS GROWN IN THE OPEN No. of plant ‘substance pro spiel water, | Total ash in. | Water abecrbet te es 209.03 52,006 18.19 oe cE pi ss GE 168. 33 42,059 16.74 2512 6 eA ae IQI.OL 46,840 20.54 Seinen O° : ee ea. 187.97 45,418 16.74 Se Wiel ea 185.06 46,447 18.86 a Eee nmr par nase 188.20 45,234 Fs we Average........ 188.42 46,344 18.25 2548 1914] BRIEFER ARTICLES 73 PLANTS GROWN UNDER SHADE No.of lant | “pubaane mo | gynetsmace,, | ganas, | stants PO etn a, 211.43 42,122 21.36 1972 A ae ee : 199.08 38,256 21.88 1748 Tee ee ey, 184.67 36,448 20.15 1809 Mee ee es 172.56 33,065 19.91 1706 es ss ak 186.80 33,922 21.56 1573 ee ee 194.27 32,407 21.61 1500 Ayerage..:...... 188.14 36,187 21.08 1718 From this table it appears that the total dry substance produced by the plants was about equal in the two sets. The plants grown in the open absorbed about 28 per cent more water than those grown under shade. The plants which absorbed and tran- spired the greater quantity of water contained both the smaller percentage and the smaller absolute quantity of ash. It appears, therefore, that the absorption of salts by roots is inde- pendent of the absorption of water, and that the transpiration stream does not exert an accelerating effect on the entrance of salts—HEINRICH HASSELBRING, Bureau of Plant Industry, Washington, D.C. CURRENT LITERATURE BOOK REVIEWS The simple plant bases A recent book by Trier’ will interest students of plant physiology and plant chemist he plant aes are divided into ice classes: (1) the high molecular, eagle active alkaloids peculiar to certain plants; (2) the simple alkaloids without known peculiarities and widely distributed in the plant king- dom; () the basic splitting products of the protoplasmic constituents, as proteins, nucleic acids, lecithins, etc. Plant alkaloids are nitrogen-containing bodies which arise in the formation or transformation of protoplasmic sub- stances. By synthetic processes the reaction capacity of their basic H atom is locked up in such a way as to render them unavailable for resynthesis of protoplasmic substances. The primary amines are the simplest alkaloids. They are formed by the Scaling’ up of the carboxyl group of the corresponding amino acids. The simplest case would be the removal of a molecule of CO:. The amines of nearly all of the amino acids are known. They are seldom found in higher plants as they are at once converted into higher alkaloids either by condensation or by the simple process of methylation, which is a very general process in plants and has the effect of throwing the methylated body out of the field of chemical activity. The betains are completely methylated amines. This relates them directly to the amino acids. They are simple alkaloids and may be further defined as substances in which one assumes an intra-molecular saturation of the amino group with the acid carboxyl group. They cannot replace cholin in the lecithin molecule. Deets, Js CH, aye ty CH, Bi — | CH; | XCH; By ay F, Coon OH Betain (glycocoll betain) (hydrated form) Cholin is formed by a Heese process of colamin — which is the primary amine of serin. This methylation occurs within the lecithin complex; therefore it is not a primary building stone of lecithin but appears only as a hydrolytic product of this substance. Xanthin bases also undergo methylation, as caffein from xanthin. The hypothesis formulated to explain the formation of the simplest amino * Trier, Georc, Uber einfache Pflanzenbasen und ihre Beziehungen zum Aufbau der Eiweisstoffe und Lecithine. pp.iv+117. Berlin: Gebriider Borntraeger. 1912+ 74 1914] CURRENT LITERATURE 75 acid includes also an explanation of the primary origin of characteristic building stones of lecithins, since the acids of the proteins and the alcohols of the lecithins arise through one and the same reaction. This would explain SToKLAsa’s finding that protein and lecithin-formation always run parallel. The formal- dehyde, formed by the reduction of CO, in green plants, is condensed to gly- colaldehyde. By the Cannizzaro reaction, one molecule of glycol and one molecule of glycollic acid arise from two molecules of glycolaldehyde. These products furnish aminoethylalcohol and glycocoll by aminization. CH,—OH | c +H,0= H os CH.—OH COOH glycolaldehyde glycol glycollic acid CH, oat OH +NH;= CH.—NH, Cc H, Sia OH “f H, O ae OH glycol aminoethylalcohol CH,—OH CH,—NH.+H,0 COOH +NH.z= COOH glycollic acid aminoacetic acid (glycocoll) This reaction furnishes, therefore, the simplest amino acid, the mother sub- stance of the simplest betain and aminoethylalcohol which may give rise to cholin by methylation as noted above. Analogous with the above reaction a furthur condensation of formaldehyde is postulated for the formation of glycerinaldehyde, and from this may arise glycerin and serin by the reaction of Cannizzaro and by aminization. We now have the glycerin for the formation of fats, lecithin, and other phosphatids. The higher amino acids may be con- sidered derivatives of serin, and alanin a reduction product of the same. The author denies the probability of HCN being an intermediate substance in the Primary formation of proteins. The author extends his hypothesis to the mechanism of methylation. By the reaction of Cannizzaro, formaldehyde can furnish methyl alcohol and formic acid. The methyl alcohol can in turn furnish the alkyl groups for the methyla- tion of metabolic products. Since this scheme is based upon the work of the chlorophyll apparatus, it will not explain the mechanism of the methylations, which frequently occur in animals. The Cannizzaro reaction is accelerated by the enzyme aldehydase, which has been definitely proven in this case to be a hydrolytic enzyme. In addition to this, if oxygen is present, the alcohols formed at the same time can be oxidized. We have here a case of an enzyme accelerating both hydrolysis and oxidation. ae 76 BOTANICAL GAZETTE [JANUARY Asparagin, the amide of aspartic acid, has usually been given an important place in studies of protein metabolism in plants. ScHutzE has shown that it must be formed at the cost of amino acids, and according to his investigations it is a secondary product of protein changes and is not a primary building stone of proteins. TRreER cites considerable evidence in support of his contention that aspartic acid, the mother substance of asparagin, is formed from glutamic acid and leucine by oxidation processes. This agrees with the fact that where there is a strong accumulation of asparagin in germination the seed proteins show a high content of glutamic aci The author’s views regarding the part played by the carbohydrates in phosphatid preparations are of great interest, since it is impossible at the present time to fit them into any scheme of lecithin constitution, although TRIER himself has proved that phosphatids from seeds contain reducing sub- stances in chemical combination. He also found that the fatty acids increase and the phosphorus decreases as the content of reducing substances increases. This led the author to think that the regular phosphatid of SrRECKER and HoppE-SEYLER must be accompanied in plants by a substance of the pare eis of animal cerebrosides, that is, substances which furnish, as I as acids and nitrogen bases but no phosphoric acid. The following scheme shows the gradual building up of lecithins according to TRIER: Formaldehyde Triglyceride Glycolaldehyde Diglyceride Glycol Diglyceridphosphoric acid Diglyceridphosphoric acid glycol ester (N free lecithin) +NH; v fatty acid I glycerin ee is Ci. ad CH, * NH, Diglyceridphosphoric acid-aminoethylester (cholamin lecithin) +3CH,0H fatty acid I Phas hs soe No o CH. * ee * ee: OH Ideal lecithin or cholin lecithin 1914] CURRENT LITERATURE five Those interested in plant physiology and plant chemistry will find this little book of great value on account of the many positive facts stated and because of the critical way in which the author has attempted to organize these facts. Some of the hypotheses may be more sweeping than the facts warrant, but they should serve to stimulate work on these important but difficult problems.— Cuas. O. APPLEMAN. MINOR NOTICES Michigan trees.—The first thing that recommends this little manual? to the student of trees is its convenient pocket size (5 by 7.5 inches), which makes it more readily useful in the field than more pretentious volumes. closer examination reveals the fact that it is well illustrated by carefully made drawings of the leaves, flowers, buds, and fruit of each species. The keys seem to have been constructed with more than usual care, and are in duplicate, one based largely upon the leaves, for use during summer; and a second making use of the bud and twig characters as a basis of identification during the winter. In order that the bulletin may appeal to as large an assemblage of readers as Possible, the use of technical terms has been reduced to a minimum, and those necessarily employed are fully explained in a glossary. The arrangement of drawings and descriptions of species upon pages facing one another adds to the €ase with which the manual may be consulted.—Gero. D. FULLER. NOTES POR STUDENTS tations and inheritance in Oenothera.—DAvis' has recently reported a continuation of his studies of Oenothera. In previous papers* he has described the F, and F, generations of hybrids between O. biennis and O. grandiflora. The present account deals with the behavior of F,and F ; generations of the same or similar hybrids. The data presented are discussed (1) from the standpoint of their bearing upon the origin and habit of mutation of O. Lamarckiana, and (2) with relation to their possible interpretation by Mendelian principles of inheritance. The latter, if one may judge from the methods employed in these studies, has been incidental to the former. The primary purpose of the investigations has been to determine the possibility of the synthesis through ybridization of a type similar in both taxonomic features and mutating habit * Ors, Cartes H., and Burns, G. P., Michigan trees. 12mo. pp. xxxiit+246. figs. 120. Ann Arbor: Univ. Mich. Bull. N.S. 14: no. 16. 1913. 3 Davis, B. M., The behavior of hybrids between Oenothera biennis and O. grandi- Hora in the second and third generations. Amer. Nat. 47:449-476, 547-371 1913- *———, Notes on the behavior of certain hybrids of Oenothera in the first hybrids of Oenothera biennis and O. grandiflora that resemble O. Lamarckiana. Amer. Nat. 46:377-427. 1912. 78 BOTANICAL GAZETTE [JANUARY to O. Lamarckiana. The results are summarized briefly as follows: “I have not been able to synthesize by direct crosses, from wild stock so far obtained, any hybrid with all of the characters of Lamarckiana in the same plant, although I believe that all of the important taxonomic characters of Lamarckiana have been represented in some of my hybrids. ... . The resem- blance of my various hybrids to Lamarckiana and the parallelism of their behavior in the F, and F; to that of Lamarckiana give in themselves sufficient reasons, in my opinion, to justify the belief in its hybrid character and to point to the probability that this plant arose as a cross between distinct forms of Oenothera. Lamarckiana thus would not be representative of a wild species of essentially stable germinal constitution and its mutations are most simply interpreted as the behavior of a rid.” Prominent among the types that appeared in F, and again in F, and bred true in a later generation—this behavior constituting the similarity to the mutation habit of O. Lamarckiana—were dwarf forms with narrow etiolated foliage, and somewhat similar dwarf forms with normal green foliage. These forms occurred in approximately 1o per cent and 15 per cent of their respective families. Other striking forms were a semi- gigas type with at least 21 chromosomes, and a form similar to O. elliptica. With relation to a possible Mendelian interpretation of his results, DAVIS most troublesome problems are: (1) “the explanation of the large groups of warfs thrown off in the F, generations and repeated by certain plants in the F.,” and (2) “the explanation of the well-defined progressive evolution, exclud- ing the dwarfs, exhibited by these same cultures.”’ This “progressive evolu- tion” consisted in the appearance of F, families whose flower size ranged from about 1 cm. greater than that of the large-flowered parent (grandiflora), to about twice as large as that of the small-flowered parent (biennis), and in a corre- sponding increase in size and amount of crinkling of the leaves. Davis doubts the possibility of explaining this advance in flower size on the basis of a recom- bination of size factors as suggested by the multiple-factor hypothesis, because there was in these families no balancing group with flowers smaller than the small-flowered parent, and he inquires: ‘“‘What had become in these cultures of the factors responsible for small size?” When it is noted, however, that at least one F, family exhibited pronounced “‘retrogressive evolution” in flower size, ‘tts aienhy will be experienced by students of the inheritance of in interpreting Davis’ results by means of the multiple- factor hypothesis. The obvious suggestion is that the several F: plants tested had somewhat different combinations of size factors, that is, that one or both of the parents were heterozygous with respect to a few quantitative factors, a condition which could scarcely be detected under the masking effect of ordi- nary fluctuation without resort to a careful quantitative study of several lines of —_ = the plants used as parents 0 of any Byte, certain F, and F; culture inexplicable to Davis on the basis of a recombination of size ‘factors, and with this the reviewer is inclined to agree. The dwarfs are much smaller than the parents, the gap ’ 1914] CURRENT LITERATURE 79 between them and the parents or the smallest of other F, forms is not bridged, and there are no compensating giant forms. It seems more likely that these plants are dwarfs because of some abnormality of function, and that, so far as to a recombination of other genetic factors present in the parents. The fact that the dwarfs have occurred in some cultures in ratios much above 1:15 need occasion little worry at the present stage of the investigations, since students of- genetics are coming to look to ratios merely for indications, and to base conclusions rather upon a factorial analysis of the material, worked out by intercrosses of the diverse types of the culture concerned or by back crosses with the parents. Davis’ results as a whole are of the greatest importance. It is hoped that he will find the time in the near future to subject his material to statistical and factorial analysis in the same painstaking way that has given-the brilliant results secured in his attempted synthesis of Oenothera Lamarckiana. HERIBERT-Nitssons has reported the results of a study of Oenothera Lamarckiana and its derivatives. His cultures exhibited numerous heritable differences with regard to such characters as color of leaf veins and leaf blades, breadth of flowers, length of fruits, and height of plants. The appearance of these minor forms in cultures of Lamarckiana is regarded as an indication that the species is not a constant one. The characteristics by which these forms are istinguished are the same, in part at least, as those that serve to differentiate the mutations of Lamarckiana. This fact suggests to the author that the muta- tions are the result of new combinations of characters, or factors, present in the parent species. € mutations that appeared in HERIBERT-NILSSON’s cultures were not identical with those of De Vries. Some of them were entirely unlike DE Vries’ mutations, while others were parallel types. Some of the latter resembled rubrinervis, gigas, albida, and Jata, for instance, in certain respects, but differed from them in others. Certain of the author’s mutants combined important characteristics of several of Dr VRIES’ mutants. One, for instance, exhibited characters of rubrinervis, scintillans, and lata. The forms studied differed principally in quantitative characters, a fact that makes a factorial analysis a matter of extreme difficulty. The behavior of certain qualitative characters, particularly red color of leaf veins, indicated that two or three Men- delian factors ts might be concerned. Ratios of red-veined to white-veined indi- viduals occurring in the F; generation of a giant form approached 3:1, 15:1, and 63:1. A complete factorial analysis of these groups, based upon a study of their Progenies, has apparently not as yet been attempted. HERIBERT- NItsson’s suggestion that giant (gigas-like) oenotheras have arisen through ‘Hertwert-Nitsson, H., Die Variabilitit der Oenothera Lamarckiana und das Problem der mutation. Petes, Ind. Abst. Vererbungs. 8:89-231. 1912. 80 BOTANICAL GAZETTE 7 [JANUARY the combination of numerous independent size factors is criticized by GATES® (1) on the basis of cytological evidence (tetraploid chromosomes) to the con- trary, and (2) on the basis of their sudden, discontinuous origin.—R. A. EMERSON. Araucarians.—Miss Ho.pEn’ has recently described the stems of two fossil plants from eastern Canada, a Tylodendron from the south shore of Prince Edward Island and a form which she claims is Voltzia coburgensis from the Triassic at Martin’s Head, New Brunswick. She has identified her specimens by the casts of the pith, and by the structure as well, and uses her determina- tions as evidence of the geological horizon of the strata in which they are found. In this connection, she states: ‘‘Since Tylodendron is characteristic of the Per- mian, there can & no question that these strata [those of Prince Edward Island] are of that age”; and of Volizia: ‘“‘Paleobotanical evidence indicates that the Mesozoic strata of New Brunswick are of the same age as those of the eastern United States, and should be correlated with the Lettenkohle or Lower Keuper of Europe.” The pith casts of her Tylodendron are typical, and she states of the ligneous structure: “It agrees exactly with that described by Dawson from Mr. Batn’s specimen as Tylodendron cyte and with that described by POTONIE as sash apes cca een pionconens Goepp In discussing t} 1 against te generally accepted view of the araucarian affinity of Tylodendron, a view, however, from which Miss HOLDEN dissents, she agrees with Poronré that ‘“‘the nodal swellings and instanding protoxylem strands causing the ridges and furrows of the pith casts are identical with similar structures in Araucaria and Agathis,’”’ but states that instanding protoxylem strands are common to all living conifers. She admits that the medullary rays are typically araucarian, the rays uniseriate, rarely over 10 cells high, and composed of thin-walled cells, but she says that all conifers have uniseriate rays. Neither of her arguments, however, precludes the araucarian connection. Of the tracheary pitting, she says: ‘Its closely compressed and alternating pits clearly affiliate it with Araucarioxylon Krauss,’’ but she consid- ers that this does not indicate araucarian affinity, since ‘closely compressed and alternating pitting is not the primitive condition for the Araucarineae.” This statement is made on the authority of Professor JeFFREY’s® recent work, While both of these articles were in press, however, the writer? advanced evidence Gates, R. R., poate mutants and chromosome mechanisms. _ Biol. Centralbl. pe 92-99, 113-150. 7 HoLpEN, Miss R., Some aa plants from eastern Canada. Ann. Botany 27: 243-255. 1913. 8 Jerrrey, E. C., The history, comparative anatomy, and evolution of the Arau- carioxylon type. Proc. Amer. Acad. 48:531-571. 1912. ® THomson, R. B., On the comparative anatomy and affinities of the Araucarineae. Phil. Trans. Roy. Soc. B 204:1-50. 1913. 1914] _ CURRENT LITERATURE 81 to show that the reverse is true. The pitting, for example, in the cone axis of Araucaria Bidwillii may be as much as 5-seriate, the pits alternating and extending from end to end of the tracheid. In this and in other primitive regions as well, the mouth of the pit is elliptical, a vestige of the more ancient scalari- form condition, a condition which is retained even longer where the medullary ray touches the tracheid. No torus is present in these regions too, although this is well developed in the whole pine alliance. Again, Miss HOLDEN says: “Impressions present more evidence for merging T'ylodendron with the araucari- ans. Several varieties of leafy branches, known as Walchia, and definitely associated with Tylodendron pith casts, have been described, all bearing a close resemblance to different species of Araucaria. Of their fructifications little is known, further than that, as shown by ZEILLER, the scales of the female cone bear single seeds, another araucarian feature.” She presents nothing in oppo- sition to the above statement, but in concluding the paragraph says: “If these criteria are reliable, the presence of T’ylodendron in the Permian strata bears out the orthodox view that the Araucarineae are the oldest living family of the Coniferales.” Since Miss HotpEn has not invalidated any of these criteria, the case must hold for the araucarian connection. She evidently fears to draw this conclusion on account of the temerity of the advocates of araucarian ances- try of the conifers, for her final point is that ‘‘there are woods of the Tylodendron type extending as far back as the Culm, yet no advocate of the antiquity of the araucarian line would suggest that it extends as far back as that.” On the other hand, Miss HoLpEN considers that her more recent form Voltzia coburgensis from the Triassic is an araucarian, but one derived from the Abietineae. She accepts the conclusion as to the araucarian affinity of Volizia, though she has rejected this conclusion in the case of Tylodendron which has one point more in its favor. The character of the rays, etc., of Voltzia is described as distinctly araucarian, just asin Tylodendron. The leaf trace is single at the pith, but forks during its passage through the wood, a similar condition, as Miss OLDEN states, to that in Agathis. She has previously (p. 246) drawn attention to “the araucarian single trace” in Tylodendron. Of the pits in Voltzia, she says that they are “always uniseriate and usually scattered . . . . rarely are they so closely compressed as to be flattened and angular. While they are as distant as the pits of the Abietineae and Taxodineae, they are never, as is the Tule in these groups, separated by so-called bars of Sanio.” This pitting is the one point of difference from Tylodendron, where the pits are typically of the Araucarioxylon type, and the one point more in favor of the araucarian connec- tion if the latter. The anatomical evidence of abietinean affinity of Voltzia is said to be “the Scattered position of the pits.” Why this is distinctive of the Abietineae is not clear. She herself states (see the quotation in the preceding paragraph) that it is found in the Taxodineae, and it occurs in other conifers as well. Nor 38 It evident why the cone is abietineous, as Miss HoLpEN states. She refers to nine authorities, only one of which agrees that it is abietineous. Three refer 82 BOTANICAL GAZETTE [JANUARY it to the Cupressineae and four put it with the Taxodineae, as the original describer, BRONGNIART, also did. No reasons are given for Miss HoLpEn’s choice. After discussing the combination of araucarian and abietinean characteris- tics in Volizia, she speaks of other forms showing similar combinations, and says: “Dr. JEFFREY . . . . appears to have demonstrated that the Abietineae are older, and that it is the Araucarineae which become ‘wiasaeatics: more and more like the Abietineae in successively older geological formations.” Certain- _ly this is not the case in the two forms she describes, even disregarding the evidence from the cone in both cases which is known in impression only. hen, however, the cone impressions are given equal i importance in each case, the fore- going is further at variance with the facts. Nor is the case improved by including the other transitional forms, which are considered important by the Harvard school, W oodworthia of the Triassic and Araucariopitys of the Cre- taceous, since the former is practically an araucarian and the latter an abietin- ean. So far then as the evidence from the transitional forms stands, the reverse of the conclusion attributed to Professor JEFFREY is the fact. It is the Abietineae which are more like the Araucarineae in the older geological formations. When this evidence is taken in connection with the fact that no true Abietineae have been described from the strata preceding the Triassic, the historical evidence is seen to be wholly adverse to the Abietineae. Miss HoLDEN’s own work then, far from supporting the abietinean ancestry of the Araucarineae, is directly opposed to it. Had the full evidence of the character of the ancestral pitting in the araucarians been before her, she would probably have escaped the pervasive influence of this theory.—R. B. THOMSON. Pityoxylon.—One of Miss HotpEn’s” three new species of Pityoxyla from the Middle Cretaceous of Cliffwood, N.J., is “probably the earliest form with all the characters of a modern hard pine, yet retaining certain ancestral fea- tures, as the association of primary and fascicular leaves.”’ She has appropri- ately designated this form Pinus protoscleropitys. Its occurrence in the Middle Cretaceous is regarded as “‘an argument for the great geological an- tiquity of the pines as such.” Her Pityoxylon foliosum is “possibly the wood of Prepinus, with all its leaves borne directly on the main axis,” and combining the characteristics of both hard and soft pines. The third form, Pityoxylon anomalum, has much the same type of wood structure as the second, but has ‘fall its leaves borne on short shoots.” The spur shoots are deaatase as large in both forms, “‘much larger ‘than those of living pines,” but unbranched, as in modern pines, and thus unlike those of Gingko, or W codsvorthin | from the Triassic whose spurs were also large. The large size of the spurs in the old fossil forms is evidence that the spur was ancestrally a branch. %* HOLDEN, Miss R., Cretaceous Pityoxyla from Cliffwood, New Jersey. Proc. Amer, Acad. 48:609-623. 1913. 1914] CURRENT LITERATURE 83 The resin canals, both horizontal and vertical, are said to be tylosed gener- ally. Since there is no evidence presented that they were ever open, this is probably not a true tylosed condition, but rather the solid condition of the ancestral forms, a condition which is very prevalent in the older fossils. It is to be noted also that in the two forms which Miss HoLpDEN considers more primitive than P. protoscleropitys, resin canals are said to be filled with thick- walled cells. In one of them, P. folioswum, where the resin ducts are very numerous, they are frequently in tangential groups of three or four. The fact that tangential series of resin canals can be revived in the living pines by injury, and that such traumatic resin canals are usually solid is in agreement with the fossil condition, and indicates that the resin ducts of the pines were ancestrally of this type. In all three forms, the pits are usually uniseriate and scattered. In P. protoscleropitys, Miss HOLDEN speaks of the terminal pits of the tracheids as eing sometimes “closely approximated and flattened by mutual contact.” She has not described this pitting in the other two. No bars of Sanio have been observed except in the former, the most specialized form. The ray pitting of its tracheids, too, shows a tendency toward the formation of “Grosseiporen,” while theirs is piciform, the more primitive condition. Tangential pitting of the summer wood is absent in P. protoscleropitys, but present in the others. She says that this confirms “the conclusions of JEFFREY and CHRYSLER that tan- gential pitting is a primitive feature now lost in the more highly specialized hard pines.” She has evidently overlooked SrRASBURGER’S previous statement of this conclusion (Hist. Beitrage 3:9. 1891), as did JEFFREY and CHRYSLER themselves. iss Hotpen’s P. protoscleropitys has the sculptured ray tracheids of a hard pine, while the other two forms have no ray tracheids. She has looked in the former for verification of the mode of origin of ray tracheids proposed by THOMPSON," from vertically elongated tracheary elements, but on finding none disparages the correctness of THompson’s work, stating that it is “unlikely that this hypothesis is correct.” She has evidently not understood the problem, for the form in which she looked for evidence is, by her own statement, a special- ized one’in this very feature. Again, she was dealing only with the stem, while THoapson worked chiefly with the more conservative organ, the root. More- over, the recent investigations of CHRYSLER,” who has thoroughly worked over € ground from the standpoint of the phloem, have confirmed THompson’s conclusion. He found the evidence in the root so much clearer than in the stem that he says he soon discontinued the study of the latter.—R. B. THomson. *THomPson, W. P., The origin of ray tracheids in the Coniferae. Bor. Gaz. 59:10I-116. 1910. “ CuRyster, M. A., On the origin of erect cells in the phloem of the Abietineae. Bor. Gaz. §6:36-s50. 1913. 84 BOTANICAL GAZETTE [JANUARY A new interpretation of mitosis——In 1911 DEHORNE published two papers’ setting forth a new interpretation for the phenomena of somatic and hetero- typic mitosis in animals and plants. According to this author, the units usually called chromosomes are in all stages of all divisions associated in pairs, each pair having the value of a longitudinally split single chromosome. At meta- phase they are not divided along this split, but are simply separated into two groups which pass toward opposite poles. During anaphase the members of each pair separate somewhat from each other and become secondarily split. After persisting through the resting stages as interlaced spiral threads, these two double structures are finally separated at the next metaphase. Thus the line of separation at any metaphase is determined during the second preceding anaphase. The diakinetic pairs are in like manner regarded as longitudinally . split somatic chromosomes. At the first maturation division one-half of these pairs goes to each pole, bringing about a reduction. During anaphase each member is longitudinally split as in the somatic mitoses. At the second division instead of separating into their longitudinal halves, they are distributed in two groups of double rods. According to this interpretation the haploid number of chromosomes in Lilium should be regarded as 6 and the diploid number as 12, rather than 12 and 24. G 4 in a very detailed description of the metaphase and anaphase in Galtonia, Trillium, and Allium, demonstrates clearly that in every case 4 dicentric separation of the halves of each chromosome occurs, and that there is no such pairing as DEHORNE has described. In a second short note’ he shows, after a careful study of Lilium, that the phenomena of maturation fol- low the heterohomeotypic scheme previously described by him, and contradict in all points the conclusions of DEHORNE. What is true of Lilium is held by GrécorrE to be generally true of all higher plants and many animals. These results, together with those of MUCKERMANN" on Salamandra and other forms, are conclusive in showing that the interpretation of DEHORNE is wholly false.— L. W. SHARP. - %B siaevcseeioa: A, , Recherches ss la division de la cellule. I. Le duplicisme con- stant du chr alamandra maculosa Lour. et chez Allium ae L. Archiv f. Zelforschung es i ie pls. 35, 36. figs. 2. 1911; Recherches su division de la cell II. Homéotypie et hétérotypie chez les Annélides poly: chet et les wecutec ae Zool. Exp. et Gén. 9: 1911. 4 Grécorre, V., Les phénoménes de la métaphase et de anaphase dans la cary cinése somatique. A propos d’une interprétation nouvelle. Annales Soc. Sci. Bruxelles 34:pp. 36. pl. I. 1912. 15 , La vérité du schéma hétérohoméotypique. Compt. Rend. 155: 1098- II00. 1912. 16 MUCKERMANN, H., Zur Anordnung, Trennung, und Polwanderung der Chromo- somen in der Metaphase und Anaphase der somatischen Karyokinese be bei Urodelen. La Cellule 28: 233-252. pls. 2. 1912. 1914] CURRENT LITERATURE 85 Soil moisture measurement.—The water content of the soil has long been recognized as the most important edaphic factor in limiting the occurrence and permanence of plant associations, but it has always been difficult to measure such a factor in terms that could be related to plant production. CRuMP,! in his studies of the vegetation of peat soils, has devised a method of expressing the relative humidity of these soils in such a manner that a definite index of water as an ecological factor is obtained. This index he has termed the “coefficient of humidity,” and it seems, for the habitats studied, to be a con- stant whose value may be determined for any given plant association. In obtaining this constant, the amount of water present in any soil is expressed in terms of percentage of the dry weight at 15° C., and the humus-content being determined in the usual way by combustion, this ratio of the water-content is obtained in terms of the humus-content as follows: water-content = coeffici f humidit humus-content Sees ee This coefficient is shown to vary directly with the amount of water available for the use of the vegetation of a habitat, and the investigator believes it to be a true integration of the relative humidity of the soil . different areas. He correction which permits it to be used for sub-peats containing large amounts of sand. Applying this unit of measurement to certain moor plant associations, he finds that the mean coefficients of humidity for the Eriophorum moor, the Calluna moor, and the Molinia moor of the Southern Pennines to be respectively 6, 3.3, and 2; and thus he is able to institute a direct comparison between the water conditions of these associations and others in the same formation. t would seem that as the result of these investigations the ecologist has been given a most important method of expressing soil moisture, far in advance of anything before available, and it is to be hoped that it will be found to be applicable to a great variety of soils—Gxro. D. FULLER. Chromosomes in Allium.—In the nuclei of Allium Cepa BoNNEVIE? has described a large chromatin knot from which the chromatin | threads radiate. In the presynaptic stages in the pollen mother cells th ea From a comparison with the origin and behavior of similar sayen threads in Crump, W. B., The coefficient of humidity: a new method of expressing the soil moisture. New Phytol, 12:125-147. 1913. * Crump, W. B., Notes on water content and the wilting point. Jour. Ecol. 1:96- 100. 1913. * Bonnevie, K., Chromosomenstudien. III. Chromatinreifung in Allium Cepa ($). Arch. f, Zellforschung 6:190-253. pls. 10-13. IQtt. 86 BOTANICAL GAZETTE [JANUARY the somatic divisions, the conclusion is drawn that this process represents a side-by-side conjugation of somatic chromosomes, which are separated at the - first maturation division. Morrrer and NoTHNAGEL,” after a study of the pollen mother cells of Allium cernuum, come to very different conclusions regarding the conjugation process. These stand in agreement with the earlier accounts of MOTTIER, and may be summarized as follows. Synapsis is a real contraction of the linin net with its chromatin granules. The thick spirem which emerges therefrom shows only an occasional temporary split in some parts. Nothing is found to indicate a union of two spirems in the prophases. During a second contraction the spirem is thrown into loops, and cross-segmentation occurs. The bivalent chromosomes so formed are regarded as consisting of two somatic chromosomes previously arranged end to end in the spirem. The members of each bivalent separate at the first division and during anaphase become longitudinally split in preparation for the second. At telophase there is formed an interrupted spirem, but there is present no chromatin knot such as BONNEVIE has described and which Morrter and NotHNaGEL believe to be due to improper fixation. The above works recall the earlier researches of BERGHS*” and of GREGOIRE” on Allium fistulosum, in which they found the bivalent ERRORS arising through a union of two spirems in the p t as BONNE- vie later found in Allium Cepa. The feures as by these writers to illustrate these critical stages form a much more complete series than those accompany- ing the contribution of Mortrer and NorunacEt. It is hardly probable that the disagreement between these accounts is due entirely to the fact that differ- ent species of Allium were used.—L. W. SHarp. Cytology of mutants.—Some of the cytological aspects of the Oenothera question are summarized by GaTeEs*® in a discussion of tetraploid mutants. O. gigas, a tetraploid form, in all probability arises through the apogamous development of an unreduced megaspore mother cell with 28 chromosomes (42); such a cell having been seen by GeErts. Triploid mutants seem to be due to the union of a diploid with a haploid germ cell (Stomps, Miss Lutz). In some plants the mutational changes are not confined to the meiotic divisions, but at » Mortier, D. M., and Norunacet, M., The development and behavior of the chromosomes in the first or heterotypic mitosis of the pollen mother cells of Al/ium cernuum Roth. Bull. Torr. Bot. Club 40:555-565. pls. 23, 24. 1913. 2t BERGHS, J., La formation des —— Lapsed cael —— la en ile végétale. II. Depuis la sporogonie j de sec Jistulosum. La Cellule 21: eee ae REGOIRE, V., La formation des gemini POON cp dans les végétaux. La cake 24:369-420. pls. 2, 1907. 3 Gates, R. R., Tetraploid mutants and chromosome mechanisms. Biol. Centralbl. 33:93-99, 113-150. figs. 7. 1913. 1914] CURRENT LITERATURE 87 many different stages irregularities in chromosome distribution may occur in a variety of ways. GarTES believes several characters of O. gigas cited by DE VRIES as occurring independently of chromosome doubling are the result of the tetraploid condition with its larger cells and nuclei. Many such differences are attributed to causes fundamentally quantitative. The interpretation of Nursson, that O. gigas originates by the accumulation of factors for size, is held by Gates to be contradicted by the cytological facts and by the sudden origin of giant types with their subsequent wide variation. Although some Oenothera characters are Mendelian in their behavior after they appear, Men- delian combinations in NILsson’s sense are inadequate to account for their first appearance.—L. W. SHARP. A heterosporous fern.—LIGNIER*™ has published a new genus (Mittagia) from the Lower Westphalian strata, which is the first heterosporous fossi fern to be described. That such a group did occur is, of course, postulated by the existence of the seed ferns, but this is the first demonstration of its presence. Licnigr, too, has sounded a note of warning by his discovery. He was at first inclined to consider that his sections were of a pteridosperm, Lagenostoma Lomaxi, so similar in structure are the outer tissues of the sporangia in the two forms. When he found four megaspores to a sporangium, a stomium pres- ent, and the sporangia arranged in a sorus, he knew that he had something different. His sporangium, however, he considers did not dehisce, and so, like Lepidocarpon, is a stage toward the seed habit. His conclusion that the sporangia belonged to a fern is based chiefly on their structural resemblance to Lagenostoma, and on their arrangement in a sorus. He has further dis- tinguished them from the lycopod and equisetum lines, from Lepidécarpon, Miadesmia, Selaginella, heterosporous calamites, etc. LicNreR’s intensive study of the small amount of material at his disposal and his logical deductions are exceedingly interesting and valuable—R. B. THOMSON. Evaporation in Skokie Marsh.—Using the Livingston atmometer, SHERFF*% measured the evaporating power of the air in a marsh habitat near the city of Chicago during the summer of 1911. The average daily rate of evaporation for the lowest stratum of vegetation was 3 cc. for the Typha association, 4.27 cc. for the reed Swamp, 4.5 cc. for the swamp meadow, and 7.9 cc. for the swamp forest of Quercus bicolor and Fraxinus americana. This forest is normally antecedent to a truly mesophytic forest such as that found by the reviewer to have an average daily rate of 8.1 cc.* During September and October of the ie * Licnrer, O., Un noveau sporange séminiforme. Mém. Soc. Linn. Normandie 24:49-65. 1913. a * Suerrr, E. E., Evaporation conditions at Skokie Marsh. Plant World 16:154- - I9t2, % Bor. Gaz. 52:193-208. rgrt. 88 BOTANICAL GAZETTE [JANUARY same season SHERFF also obtained data upon the evaporation rates in different strata of the marsh vegetation, showing the evaporating power of the air to be 300 per cent greater in the top stratum of the Phragmites association than in the lowest, while the difference became three times as great in the Typha associa- tion. These results confirm those of Yapp” for a sedge vegetation and those o the reviewer for the beech-maple forests, warranting the conclusion that plants - may grow in proximity with each other and yet, vegetating in different horizon- tal strata, be subject to widely different growth conditions.—Gro. D. FULLER. History and origin of monocotyledons.—Horwoopb” has done useful service in bringing together, in convenient form, the evidence of fossil monocotyledons. The record of each family is recited, and the summary shows that the first authentic specimens are from the Cretaceous, and that in the Tertiary or Post- Tertiary 24 families out of about 30 are represented. In dealing with the origin of monocotyledons, Horwoop gives a synopsis of most of the views that have been advanced and reacees = following general conclusion: that the monocotyledons and dicot ivergent series from a common ancestor; that among the dicotyledons there has been “‘progression and differentiation,” while among the monocotyledons there has been “‘retrogression and even some reduction from a common ancestor of the primitive angiospermic type.” This primitive type, by the way, ‘“‘resembled an alismaceous or liliaceous type, on the one hand, and a ranalian type on the other,” and in the background of this primitive stock the author sees the Cycadafilicales and Bennettitales. The mass of facts brought together will be very uSeful, even if the conclusions are not convincing.—J. M. C. Fourth International Botanical Congress.—The first circular of the Inter- national Botanical Congress of 1915 has been issued. The sessions will be held in London from May 22 to May 29. Membership is secured by subscribing to the regulations of the congress and by the payment of a subscription of 15 shillings. Ladies accompanying members may attend the meetings and excursions of the congress on payment of 10 shillings each. The presidents of the organizing committee are Professor F. O. Bower, Sir Davip PRAIN, an Professor A. C. SewaRD. The general secretary is Dr. A. B. RENDLE, British Museum, Cromwell Road, London, $.W., to whom applications may be made. R. H., On stratification in-the vegetation of a marsh, and its relations to evaporation and temperature. Ann. Botany 23:275-320. 1909. #8 Bor. GAZ. §54:424-426. 1912. 2 Horwoop, A. R., The past history of monocotyledons, with remarks on their origin. Scottish Bot. Review 1:164-180, 216-234. pls. 1-4. 1912. Volume LVII Ps one ikea e 84, Cat uols .R The Botanical Gazette A Montbly Journal Embracing all Departments of Botanical Science Edited by JoHN M. CouLTER, with ar res ag of a! members of the botanical _ of the tsity of Chic 283) February ei ee Vol. LVII CONTENTS FOR FEBRUARY 1914 No. 2 STUDIES ON THE REACTIONS OF PILOBOLUS TO LIGHT STIMULI hen TWELVE FIGURES). Haily D. M. Jolivetie MORPHOLOGY OF THISMIA AMERICANA. CONTRIBUTIONS FROM THE HuLL BoraANIcCAL LaBoraTory 182 (WITH PLATES vu-x1). Norma E. PLGA 3 «41 Fs 122 CONCERNING THE PRESENCE OF DIASTASE IN CERTAIN RED ALGAE. E. T. Bartholomew oe aie sa se Se ee ee weg) See tee Tee THE MALE GAMETOPHYTE OF ABIES (WITH FIFTEEN FIGURES). A. H. Hutchinson - 145 Pho mish pila & oe pe me oe a > Bs a z zs ~ 354 hat FUNGI. NOTES ae wih eee: Sg ey Sh BOP Pee Ot oe a Se ee Ee ee te COG aes The Botanical Gazette is Jeorse a monthly. 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Twenty-fve ¢ separates of origina articles without covers will be supplied gratis. “A table eins approximate i of additional 2 =e ve , printed on an } ordee blank k which aecom 5 Rea g,* the Afican ee: Bei will be sent on request. ee r, 1896, at the Po x : "4 ae Be VOLUME LVII NUMBER 2 THE BOTANICAL © able FEBRUARY ro14 STUDIES ON THE REACTIONS OF PILOBOLUS TO LIGHT STIMULI Hatsy DM. Jorivette (WITH TWELVE FIGURES) The present investigation concerns itself for the most part with the problems of simultaneous stimulation. It was under- taken with a view to settling some of the problems suggested in a former paper on the light reactions of Pilobolus by Miss ALLEN and myself (1). Some of the objections inherent in the methods used in the earlier work were eliminated in the experiments here reported, and a study was also made of the reaction of single sporangiophores toward the light. The work was begun under Dr. R. A. HARPER at the University of Wisconsin and completed: under Dr. G. J. Petrce of Leland Stanford Junior University. I wish to acknowledge my indebted- ness for their criticisms and suggestions. I wish also to express my gratitude to Dr. D. H. CampseE t for his interest in my work and for his courtesy in extending all the privileges of his laboratory. I thank Miss RutH F. AtLEN, who began the study of the reactions of a single sporangiophore of Pilobolus toward the light and furnished the data taken on the evenings of May 18 and 109, IgIo. The present study of simultaneous stimulation by light is on the question of directive influence, and the literature discussed will concern that phase of light effect. The early work was carried on with light and gravity as the stimuli. Nott (4) in 1892 pub- : 89 go BOTANICAL GAZETTE [FEBRUARY lished his theory of ‘‘heterogene induction.”’ He reviewed the earlier authors on the subject and described their conflicting results. According to Notw’s theory, if an organism is subjected to two stimuli, one gives impetus to the other which carries out the reac- tion. One stimulus only is responded to. There is no resultant | reaction toward the two stimuli. But when light and gravity work together, there is a change of geotonus due to light. Recently GUTTENBERG (2) studied the simultaneous effect of light and gravity, using seedlings of Avena sativa, Brassica Napus, Agrostemma Githago, and Helianthus. He used what he called the compensation method. He tried different light intensities. With the higher intensities the reaction was toward the light alone. By gradually decreasing the intensities, GUTTENBERG found a certain light strength which just equaled that of gravity, and he obtained a resultant reaction between the two. A little weaker or a little stronger light gave a resultant reaction, varying according to the intensity of the light. GurTrreNBERG considers this as evidence against NoLv’s theory of ‘‘heterogene induction.” RICHTER (5), working along the same lines as GUTTENBERG, came to quite different conclusions. For his experiments RICHTER “used Avena sativa, Vicia sativa, Vicia villosa, Brassica Napus, and Helianthus. He followed GuTTENBERG’s method and in each case carried on a set of experiments in pure air and a similar one in impure air. He concludes that GuTTENBERG did not establish a resultant reaction between the effect of light and gravity by means of his compensation method, but that the latter’s results were in- fluenced by the impure air in which the experiments were performed. GUTTENBERG (3) followed this by a second paper in which he still maintained his former views. In this he repeated his own experi- ments, taking precautions to work under pure air conditions. The experiments on simultaneous stimulation reported in this paper were performed with stimuli of the same kind, that is, they were light stimuli only. Before entering into a description of the work of simultaneous stimulation of Pilobolus, an account of some observations made on the reaction of a single sporangiophore of Pilobolus will be given. 1914] JOLIVETTE—PILOBOLUS QI Study of the reactions of the individual sporangiophore to a single. light In the earlier experiments (2), and also in those on simultaneous light stimulation in this paper, I was concerned with a large number of sporangiophores and with the net result of the reaction. This set of experiments was inaugurated for the purpose of following in detail the stages in the reaction of the individual sporangiophore toward light. The horizontal microscope was employed for this purpose. A culture of Pilobolus in a 5-cm. flower pot was used. The pot was supported in an upright position. A thin glass Petri dish, measuring 5 cm. in diameter and 4 cm. in height, was placed over the top of the flower pot to keep the culture from drying. A 16-c.-p. carbon filament incandescent light was placed at a dis- tance of 30 cm. from the culture, with the central point of the fila- ments 5 cm. above the level of the surface of the culture. The experiments were performed in the dark room and no other light had access to the culture. A horizontal microscope was placed with the tube on a level with the surface of the culture and at right angles to the direction of the light rays reaching the culture, so that _ any bending toward the light could be observed. A micrometer scale was placed in the ocular of the microscope in order to measure the change of position of the sporangiophore. In favorable cases several sporangiophores could be observed in the field of the microscope. The first culture used in these experiments was put in place at 7:15 P.M. The sporangiophore had been exposed to the after- noon light and had grown straight out toward it, making an angle of 45° with the vertical. The culture was placed with the sporangio- phores leaning away from the light, so that the angle between the light rays and the sporangiophore was about 135°. At the time when the experiment was set up, the young sporangiophores showed no signs of the sporangial swelling or vesicular bulb. Two sporangiophores were observed during a period of 3 hrs. on the evening of May 18, 1910, and sketches were made at inter- vals during the reaction. The exact time when the reaction of the 92 BOTANICAL GAZETTE [FEBRUARY first sporangiophore became perceptible was not determined. The reaction was distinctly visible at 7:45, 30 min. after it was exposed to the light. So far as could be seen, the curvature began at the tip of the sporangiophore, the tip bending as it grew. The tip distinctly started to curve upward at 7:45. This curve was some- what more pronounced at 7:50. The tip was vertical, having moved through an angle of 45°. The radius of curvature was short. At 8:40 the tip had grown so that it was no longer vertical, but made a smaller angle with the incident light rays. At 9:30 the tip had grown around so that it pointed in the direction of the light. It had curved about 135° since the beginning of the observation. The curvature took place as the growth occurred; the curved end of the sporangiophore at this period was a well rounded hook. From SOX Fic. 1 this time on the tip grew straight toward the light. The last observation on this sporangiophore was made at 10 P.M. and showed a pronounced growth in the direction of the light. Fig. 1 shows the stages that were sketched. The arrow indi- cates the direction of the light. The bending in this case had taken place always at the tip, the growing point of the sporangiophore. The older basal portion of the sporangiophore appeared to main- tain the form and position which it had at the beginning of the experiment. If there was any change, it was so slight as not to be detected with the microscope. The behavior of another sporangiophore under observation at the same time was as follows. The reaction was somewhat longer, no sign of curvature being noticeable until 8:00 p.m., 45 min. after the beginning of the experiment. The bending progressed slowly. At 8:40 the tip had curved through 45°, the curve being gradual. 1914] JOLIVETTE—PILOBOLUS 93 At 9:15 the tip seemed to have stopped bending and to have grown straight. The angle made with the light was 60°. From 9:15 to g:50 the increase in length was slight, and the older portion of the curve seemed to have become slightly more bent. At 10:15 the terminal sporangial swelling was well defined and the limits of the vesicular bulb could be discerned. The direction of the tip remained unaltered and formed an angle of 60° with the incident light rays (fig. 2). A group of , sporangiophores on the same cul- ture as the two de- scribed above and SS h subjected to the bs ¢ same stimulation from 7:15 P.M. until 9:55 were observed at 9:55. Three of them were still turned in the direction from which the afternoon light had come and away from the light used in the experiment. Apparently there was no response toward the light stimulus. In these three cases sporangium-formation had begun. The fourth sporangio- phore had been subjected to the same conditions. The tip was curved through 135° and proceeded to grow in the direction of the light. The tip was still slender and pointed. The difference in length between this one and the other three was noteworthy. It ex- Fic. 3 ceeded the other three by the length of the portion beyond the bend where it turned toward the light. The sketches of the four sporangiophores as they were at 9:55 are shown in fig. 3. _ At 8:15, May 19, 1910, an older culture was used. Sporangium- formation had started when the observations were begun. At the beginning of the experiment the five that were chosen for study were at different stages, the youngest showing the sporangium as a 94 BOTANICAL GAZETTE , [FEBRUARY small yellow knob, and the oldest having its sporangium full grown and turning black. They were all pointed in the direction of the afternoon light, making an angle of 135° with the incident electrical light rays. The five were watched closely from 8:15 to 9:55 P-M., the position of the tip of each being observed and recorded every 5 min. During this time their development continued normally, the sporangia of the younger ones swelled, turned gray, and then nearly black, and the vesicular bulbs of all increased in size. In no one of the five was there any sign of bending toward the light, although they were watched for 1 hr. and 40 min. On the evening of May 21, 1910, observations were made on the reactions of three sporangiophores. The light was turned on at 7:38. The sporangiophores were inclined away from the direction of the light at an angle of 125°. The sporangial swelling in all of them was yellow. The vesicular bulbs had not begun to form. At 8:02 the sporangiophores had grown 1 mm. in length, but there was no change of position due to the presence of the light. The observation was continued until 9:20 p.m. The sporangiophores had not reacted toward the light, although they had continued their normal development. At 9:20 P.M., January 19, 1911, observations were begun on six sporangiophores. They were in the same field. The light was turned on at 7:20 P.M. and observations were made for 2 hrs. One of the sporangiophores stood vertically. It was slender tipped and showed no signs of sporangial swelling. At 7:50, after 30 min. _ exposure to the light, the tips showed a very slight curvature. The reaction then stopped and the tip began to swell slightly. When the light was turned off, the sporangial swelling was distinct. The remaining five sporangiophores at 7:20 stood at an angle of 135° to the incident light rays. All showed sporangial swelling, but the vesicular bulb had not started to form. There were no indications of response toward the light in any of them, although the sporangiophores continued their normal development through- out the experiment. At the close of the experiment the swelling of the vesicular bulb on all of them was just visible. Fig. 4 shows a sketch of these sporangia as they appeared at the beginning of the experiment. 1914] JOLIVETTE—PILOBOLUS 95 At 7:27, January 20, 1911, the light was turned on a culture which had been exposed to the afternoon light, and observations were begun on five sporangiophores which were visible in one field. The first sporangiophore made an angle of about 80° with the direc- tion of the light. It was slender tipped. At 7:58 the tip showed a slight increase in length and this portion was very slightly curved toward the light. At 8:23 there was a slight increase in curvature t | toward the light. At 8:42 the tip had curved through 35°, making an angle of 45° with the light. At 8:50 the curvature had increased so that the angle between the direction of light and the tip was only 25°. At 9:30 the tip was pointed directly toward the light. From this time the tip grew directly toward the light (fig. 5). The second sporangio- phore observed was in much the same condition at the beginning of the experiment as the one just Pe. 4 described, except that it was about 1 mm. longer. The reaction in this case was first noticeable at 8:00 P.M., the curve being barely visible. The curvature then proceeded more rapidly, and at 8:35 appeared more strongly than in the others in the field. At this time it had passed through an angle of 30°. At 8:42 the angle traversed was 45°. At 8:50 the angle made with the I \ } \ a o ay direction of the light rays was barely more Fic. 6 than 10°, and at go:1 the tip was directed straight toward the light and it continued in that direction until 9:50, when -the observations were concluded. The portion beyond the curve was then about three-fourths of the length below (fig. m Fie. 4 96 BOTANICAL GAZETTE [FEBRUARY The third sporangiophore was inclined at an angle of 80° from the incident light rays and measured 4mm. in length. It was slender tipped. Curvature was first visible at 7:58 and at 8:42 was still very slight. At 8:50 there had been a slight increase in length, although no further change in direction was noted. Atg:40 the curvature became more pronounced and at g:5o the tip was pointing almost directly toward the light. At this \\ \\ A\ time the curvature seemed to be arrested. No further observations were made on this sporangio- Fic. 7 phore (fig. 7). The fourth sporangiophore Saerved at the same time stood at an angle of 80° with the direction of the light. It was 2 mm. in length and the tip was slender and tapering. The reaction in this case was strikingly like that of the third sporangio- phore just described. They were very near together (fig. 8). The fifth sporangiophore measured 1 mm. in length at the beginning of the experiment. It was slender tipped and stood vertically from the surface of the culture. At 8:04 the tip had begun to curve. At 8:42 the \ \ \ tip had curved through an angle of 40°. At 9:13 Fic. 8 it pointed in the direction of the light (fig. 9). Observations were begun on two sporangiophores on one culture at 7:40, January 21, 1911. They were slender tipped and made an angle of about 50° with the direction of the light. At 8:18 both showed new growth which was curved slightly toward the light. The curvature continued with the growth until at 8:50 the tip was directed straight toward (\ )\ the light. From that time until ay ea 9:50 when the observations were Fic. 9 concluded, the sporangiophores grew in the direction of the light (fig. 10). A group of five ca iachores was located in the field of the horizontal microscope at 8:40 P.M., November 2, 1911. The spo- rangiophores showed only slight differences in length and were inclined at an angle of 25° from the vertical. They were placed so that they leaned away from the light, making an angle of 95°. The sporangial swelling was just visible on the tips of all the spo- 1914] JOLIVETTE—PILOBOLUS 97 rangiophores. They were observed continuously, but there was no sign of a bending toward the light until 3:00 a.m. Meanwhile, the sporangial swelling had increased in size and the vesicular bulb was barely visible. At this time the sporangiophores were curved slightly at some distance below the sporangium nearer the direc- tion of the lamp. Observations were not made again until 4:30, when the sporangia were aimed directly toward the light and the vesicular bulb was distinct; the curvature was in the region imme- diately beneath the : vesicular bulb. -At 6:30, when the ob- MI An [in Me a a servations were con- ea. ys cluded, the bulbs had swollen considerably. The sketches (fig. 11) show the develop- ment of one of the sporangiophores of the group. The development of all the others were remarkably parallel with the one described. Observations were begun using a second horizontal microscope on a sporangiophore at g:00 p.M., November 2, tg11. ‘The tip of the sporangiophore was just beginning to swell. The sporangium was standing vertical to the surface of the substratum. The light was placed at the angle above mentioned. The development of the sporangial swelling continued, but no reaction toward the light was visible at 11:35. Observations were made con- tinually until 3:00 A.M., when the sporangium was rather well formed and the vesicular bulb barely visible. ; On the evening of November 3, 1911, two Fic. 11 sporangia were observed for the first time at 10:40. The first sporangiophore was yellow and rather blunt tipped, but as yet it did not show sporangial swelling. It stood at an angle of about 20° from the vertical, thus being inclined away from the light at an angle of go°. There was no sign of a response toward the light at 12:00 P.m., but the tip then showed the sporangial swelling. At 2:05 A.M. the sporangio- phore began to curve toward the light, the region of curvature being then located at some distance below the sporangial swelling. At 2:15 the curvature was more pronounced but still confined to the 98 BOTANICAL GAZETTE [FEBRUARY same region. The bending continued until 5:30 a.M., when the tip of the young sporangium pointed directly toward the light. The entire portion between the region of bending and the young sporan- gium was swollen slightly, showing the beginning of the formation of the vesicular bulb. At 6:30 the vesicular bulb was large and turgid (fig. 12). At the beginning of the observation the second sporangiophore in the same field of the microscope was somewhat longer than the first and the sporangial swelling was well formed. This sporangio- phore also formed an angle of 90° with the light. The vesicular bulb was not yet visible. At 2:15 the sporangiophores had curved through an angle of 20° nearer to the direction of the incident light rays. The curvature in this case was also at some distance below the sporangium swelling, and the space between the two was WELT beginning to show signs of the formation of the vesicular bulb. At 5:30 A.M. the tip of the sporangium was aimed toward the light. The vesicular bulb was still very inconspicuous. The bend in the sporangiophore was well rounded and had grown in length since the beginning of the curving. At 6:30 the vesicular bulb had swollen so that it exceeded the diameter of the sporangium by twice the diameter of the latter. At 8:00 the development appeared fairly complete. The sporangium was discharged between 9:50 an 10:00 A.M. (fig. 12). From the foregoing experiments the following conclusions are evident: 1. Growth takes place at the tip in the young sporangiophore. 2. It is in the growing tip that heliotropic curvatures are formed. 3. In no case has a heliotropic curvature been observed during stages in early sporangium-formation. r9r4] JOLIVETTE—PILOBOLUS 99 4. Sporangium-formation may start during a reaction; in such cases the reaction is delayed for some time. 5. Incase the reaction toward light isinterrupted by sporangium- formation, it is resumed again a little before or about the time when the vesicular bulb is beginning to form. 6. After the sporangium is formed, the growing and curving portion is located immediately beneath the vesicular bulb. The reaction of Pilobolus when exposed simultaneously to two equal sources of light The effect of exposing a culture of Pilobolus simultaneously to two equal sources of white light was studied. For this purpose a light-proof box, measuring 120 cm. long by 60 cm. wide by 60 cm.. high, was used. The box was made of pine and was painted a dull black on the inside. Running horizontally across one end, 20 cm. from the bottom, was an opening 10 cm. wide. Into the opening, which was prepared with rabbeted edges, was introduced a gal- vanized iron strip containing two openings 1 cm. in diameter and g cm. apart. The culture was placed at a distance of 25 cm. from the central point between the openings and on a level with them. It was placed with its surface vertical and facing the side of the box containing the openings. The object of the experiment demanded that the light from the two openings be equal, but I know no methods of obtaining abso- lutely equal light intensities. We can only know that they are approximately equal. In order to obtain as nearly as possible equal illumination at the two openings, one light of measured intensity was placed equidistant from the two openings of the box and 40 cm. in front of it. Two mirrors were so adjusted that the culture intercepted the single spot of light formed by the con- vergence of the two sets of light rays. The light from either mirror was excluded from the opposite opening by means of the following device. At right angles to the edge of the box, along a line equi- distant from the two openings, was placed an upright piece of board measuring 60 cm. high by 30 cm. wide by 1 cm. thick. At right angles to the first piece and parallel to the end of the box was nailed a second piece measuring 60 cm. high by to cm. wide by 5 mm. thick. I0oo BOTANICAL GAZETTE [FEBRUARY Both of the pieces were painted a dull black. The surface of the culture was covered with black paper, exposing a circular area 2 cm. in diameter. This small area was selected in order to exclude objectionable features such as unevenness in surface of culture, irregularity of distribution, etc. The number of sporangia was thus somewhat limited, but the undesirable features above men- tioned were minimized. This set of experiments was carried on in a dark room at the University of Wisconsin during April, May, and June 1910, under the direction of Dr. R. A. Harper. As previously described, a new set of sporangia matures daily and is discharged in the forenoon or early afternoon. The records of the results of the experiments were made daily in the late after- ‘noon or evening. A glass plate fitting inside the box and against the openings caught the sporangia as they were discharged toward one or the other of the two lights. The data were then recorded by means of a chart devioed to meet the requirements of the experiment. The chart consisted of a large white sheet of paper divided by means of parallel lines into vertical strips 1 cm. wide. This is the principle of the Wolfhiigel counter used by bacteriologists, and it was well adapted to the work and. The pieces of glass covering each of the 1-cm. openings fitted into the 1-cm. strips. In recording the data, the sporangia falling above and below the opening in the 1-cm. strip are recorded with those striking the opening. This is entirely fair, since, owing to the object of the experiments, we are concerned only with lateral distribution. Furthermore, our earlier experiments showed clearly the conditions of vertical distribution. The data for these experi- ments are recorded in table I In the first experiment 86 sporangia were discharged on the glass, 29 striking the vertical area containing the opening to the left and 25 that to the right. In the second experiment the total number was 60; 5 of these were on the area of the left opening and 200n the right. In the third experiment 59 sporangia were counted on the glass, 5 and 18 being found on the left and right openings respectively. In the seventh all of the 22 sporangia discharged were fired toward the right opening, 10 of them striking the vertical 1914] JOLIVETTE—PILOBOLUS IOI area containing the opening. Experiment 26 shows a total of 142 sporangia, 54 striking the vertical strip of the left opening, 30 that of the right opening. Experiment 27 shows 39 and 58 out of a total of 204 sporangia on the left and right openings respectively; and in experiment 28, 334 sporangia were discharged, 84 on the left and 78 on the right opening. Throughout the series of experiments some of the sporangia failed to hit either opening. In experiment 1, 32 of the 86 spo- rangia discharged were of thissort. The distribution on either side of the two openings showed considerable variation. There were 9 sporangia in the 1-cm. strip to the left of the left opening and one sporangium in each of the next two strips. In the first 1-cm. strip to the right of the opening were 6 sporangia. On the left side of the right opening there were 11 sporangia in the first strip and 1 in the third; 3 sporangia were found in the first strip to the right of this opening. In the second (table I), 3 sporangia struck the glass within 1 cm. to the left of the left opening. In the first, second, and third strips to the right of the opening were respectively 4, 2, and 1 sporangia. To the left of the right opening were 5 sporangia, all within the first strip. The number of sporangia in the first three consecutive strips to the right of the opening were respectively 18, 1, 1. The distribution and number of scattered sporangia in the remainder of the experiments showed about the same degree of variation as indicated by the complete data (table I). In the foregoing experiments the number of sporangia which strike the openings does not appear especially large. These alone do not by any means give a complete conception of the accuracy of the total discharge of sporangia. A further knowledge of the distribution of these sporangia serves to correct the erroneous impression given by stating only the numbers that reach or do not reach the opening. The accuracy is very striking, for further con- sideration shows that 29 of the 32 sporangia that missed the opening in the first experiment were found within the 1-cm. strips on either side of the openings; only 3.5 per cent fell outside that area. A perusal of the remaining data shows practically the same accuracy of discharge. The greater portion of the sporangia that 102 BOTANICAL GAZETTE : [FEBRUARY failed to strike the openings were found in the strips adjacent to the openings and only a very small percentage fell outside this area. It is plain from these data that although there is much varia- tion in the number of sporangia fired toward the two openings, the sporangia cluster about each of the openings and show no tendency to strike between the two. The sporangia are discharged, there- TABLE I ‘ ‘ fe eo a 2 35 “a a a a: i) 8. a 3 B =) io) 86 I 1] gl29| 6 I 11/25] 3 --| = 60 3) 54-4031 si20] 18) x | 12 Bae Meee 590 4 ieee a 3 3| rolrS | rol 2{ r{ri...| 3 56 ed ae ees .| 2 a st Seta Oe) 2 aft 25 Cee in ae tee pray Ceerd Gent 9 ae sa iy at oe ee a a ee 41 219] 4! 2 hs ae iS (a Se oe Bee ob de ere Oa 22 : Ce RE HIS a EF Py ea 35 ee a eg or a OR eT Ales | | 8 as ee 5/13 Ee ee eek be ead EE REE els -| 9 36 Sie a Ae hgh stat et 2 | x .| TO 54 Ore ty Stet 2 Pick al at Gas wg 4 2 Ir 29 I 1. Sts Ij 2 Clb a 7 Ree Gee eae 12 24 2) 4 a} :2 : a ee eee ae 13 24 Il 9 3 r| & I 14 14 Ij 4 5 ek Theecte 15 24 a ey a ee x} x} 3] ¢ sae 16 a0 as 3 re Pat eae 31 7 12 4 eek ree ey a 1}. I ene 18 20 I EL, ot pal ee a 7 eats 19 7 2 2 12 een a Uae Oe 4 35 t)--3\20.| 8) 2 RE BE Pte os [es fe 27 2;8) 2) 4 2| 3 Pot 22 14 5 I is aa Pees 23 22 114 Dee aoe oe ye ies. Bale 24 34 6/12 eet ck a becals “eae 2 ae 25 142 e}55.| 4) 20134 | 27) 2) 2 hy r0ig0) 6) 2 |. 20 204 2131] 4! 231390! of 613 I tl 7| 20158 | 20| 4 |. 27 334 |- r|x}21| 3] 24184| 2315] 4]2]6] 3] 9} 34/78] 30) 8} 2/313 | 28 133 I 2) 8 a GE Sas Be 2 3} 6} 16/32 Pe ay oes Bee 29 178 |. Ete ts 8} 26/52 | 28} 6 | 1] 2412 1| 2| 16jaz GS tee ee 1 | 3° 146 I A aaiae Sta a a |. ft 3 4) azi4g | 7|-<:| 3 |---].2 | 3% 24 I 2 ie Gs Os tn ee ae FN es ee Ca Wd I Bian 252 1|/2/3|2{/31] 5] 25a5| 16)8|51]41]5]| 5] 12] 22144] 3319] 91| 8 | 6 | 33 61 2 2 2 Stato) I wits | 4) 371 2 | 2 )---| 34 30 |. [2 ee I 2 pron Para we aia ae 4.2) 41.2 GE ficctescte+s} So 176 |. x|21]5]| 17} 15] 9] 6)...| 3 |...| 8 | 23].25| 20lz9 | 13| 5 | 8 | 4 | 3 | 3° fore, toward one or the other of the two lights. In other words, as shown by the earlier set of experiments, there is no resultant reaction due to the presence of the two lights. If there were, the sporangia would be for the most part between the two openings. It is clear, therefore, that this simple organism, when subjected simultaneously to two equal light stimuli, will respond to one of the two stimuli, to the complete exclusion of the other. -Ior4] JOLIVETTE—PILOBOLUS 103 The sporangia, however, are not discharged in equal numbers toward the two openings. In the extreme case all might go to one or the other of the openings. It happened that in only one case (experiment 7, table I) did this occur, and then the total number was 22, the number being small and affording less chance for variation than would a larger number. The entire data thus show a great diversity of results as regards the number fired toward either opening. It is significant that the element of chance enters strongly into these results. The fact that the sporangia do fire toward one or the other opening and in any degree of variation suggests further that although a large number of sporangiophores arise from one myce- lium, they are not gregarious as regards physiological response toward light stimuli, that is, they act as separate individuals toward a light stimulus. A further set of experiments was arranged to determine whether the sporangia to the right of the culture are discharged toward the right opening and those to the left of the culture to the left opening. With the apparatus arranged as before, a second series of experi- ments was made with a thin plate of glass placed with its edge vertical to the middle line of the exposed surface of the culture. This glass would then intercept the sporangia discharged from the left side of the culture to the right opening and vice versa. In the first experiment 2 sporangia struck each of the two openings, the number of sporangia in the consecutive 1-cm. areas to the left of the left opening are 8, 6, and 1; 3 sporangia were found on the 1-cm. area to the right of the opening. The first, second, and third 1-cm. areas to the left of the right opening con- tained respectively 1, 2, and 1 sporangia. The glass placed verti- cally at right angles to the surface of the culture received 7 sporangia on the left side and 15 on the right. The distribution of those on the left was as follows: 4 in the rst cm. toward the culture, 2 in the 4th cm., and 1 in the 7th. The distribution of the sporangia on the right-hand side of the glass shows 7, 5, and 3 in the first 3 cm. These data, together with those of the second and third experi- ments made in this series, are found in table II. These experi- ments tend to show that some of the sporangia on the right side of 104 BOTANICAL GAZETTE [FEBRUARY the culture fire toward the left opening and vice versa. Some of this may be due to reflection from the glass. TABLE II The culture maa ance and facing the two openings; a glass plate pees oe openings; a second glass plate at right angles @ the waters e B of the a tur e- a data i cont the plates given in the first pa of the nh lture are retested to by the marks *, f, a to oo a rey xi | i ‘3 §| Date 8 a a i z 3S a a 3 = (Ss) ro) 4 26 ¥)O6} 8 |} a13 21211 1* | 6/15/10 7130 P.M. 7 I 2 red Be Ve Be at |6/16/’r0 7:35 P.M 38 r1}4)]7]9 I I Se hepa as 3t | 6/17/10 *Sporangia discharged on glass at " .-.[--[ 2 |.../...[ 2 [...[-..[ Surface of glass to left of culture right angles to surface of culture}|7 | 5 | 3 « eee Msg so ft Sporangia discharged on glass at i. 3 sd oe tet pegs right angles to surface of culture!\2 | t | 2} 2{1/...]...|...| 2 . pitta fs a. —. on glass at “ ee gy eet "is of culture bis eee Te Pe oir sem SNe peers mee! “ « “ “ yight “ a The behavior of Pilobolus when given two equal sources of light but with the angle between the two sets of incident light rays varied The box used for this set of experiments was made of redwood and measured 120 cm. long by 45 cm. wide and 35 cm. high. hinged cover was so rabbeted as to be light-tight and was supplied with ice box catches in order to fasten it down tightly. At one end of the box, 14 cm. from the base, was an opening 9 cm. wide all the way across from side to side and so arranged with galvanized iron rabbets as to carry strips of galvanized iron 10 cm. wide which just closed the opening. These strips contained the openings through which the light was admitted to the culture. They were made of galvanized iron so that they would be thin enough to avoid shadows being cast by the rim of the openings. The openings were I cm. in diameter and their centers were the following dis- tances apart: 1cm., 2cm., 3cm., etc. The inner surface of the slide containing the Spening was flush with that of the end of the 1914] JOLIV ETTE—PILOBOLUS 105 box, so that the glass plate on which the spores were caught fitted closely against the slide containing the openings. The openings not desired could be closed by means of two additional slides fitted in the groove from either end and outside the slide containing the openings. ‘The inside of the box and of the strips was dull black. The culture in this series was kept throughout the experiment at a distance of 23 cm. from the central point between the two openings. The surface of the culture was vertical and faced the slide containing the two openings. The exposed surface of the culture was 2cm. in diameter. The light entering each of the Openings was made to fall upon the exposed surface of the culture. » The intensities of the light entering the two openings were equal or as nearly so as they could be made by measurement. The follow- ing device was followed in order to make the lights as nearly equal as possible. A single carbon filament incandescent lamp was placed at a distance midway between the two openings. By means of two mirrors placed at equal distances and equal angles one on either side of the lamp, the light was reflected through the opening to the exposed surface of the culture. In order to exclude the light of either mirror from the opposite opening a partition was set up in front of the box midway between the two openings, exactly similar to that used in the set of experiments last described. With the change in the distance between the two openings it Was necessary to change slightly the angles of the mirrors from the light in order that the spot of light reflected from the mirrors through the openings would strike the exposed surface of the culture. The condition of the experiments thus necessitated a slight change of light intensity from experiment to experiment, but the intensities of the light passing through the two openings at any one time were equal. This set of experiments was performed in a dark room in the botanical laboratory of Leland Stanford Junior University. In the first experiment, when the distance between the centers of the two openings was 5 cm., a total number of 38 sporangia Were fired on the glass, 10 and 13 striking the left and right openings Tespectively. Only 2 of the 15 sporangia which failed to strike the opening were outside of the adjacent 1-cm. strips. 106 BOTANICAL GAZETTE [FEBRUARY In the second experiment, with the center of the openings 4 cm. apart, 19 sporangia struck the glass; 1o were on the left opening, 7 on the right. Of the remaining 2 sporangia, 1 struck in each of the 1-cm. strips to the left and right of the left opening. The third experiment shows a total discharge of 63 sporangia. Of that number 16 struck the left opening and 20 the right opening; 27 failed to reach either opening, but all of that number, excepting 3, were within 1 cm. of the opening. When the distance between the openings was 14 cm., ‘6 spo- rangia were discharged, 15 striking each of the openings; 6 sporangia were counted within the first 1-cm. strip to the left of the left opening, and 1 in the third strip; 3 and 2 were within the first and second strip to the right of that opening; 5 sporangia struck within the 1-cm. strip to the left of the right opening, and 2 and 1 in the first and second strips on the right-hand side. 3 With a distance of 27 cm. between the two openings, 200 sp0- rangia were discharged on the glass, 61 and 37 striking the respective openings to the left and right. The majority of scattered sporangia are again grouped around the two openings. The data for these experiments are tabulated in complete form in table III. The results of the experiments in which the distances between the openings were varied agree with those obtained in the preceding set of experiments, where the openings were kept at the same dis- tance throughout the set of experiments. The sporangia were fired with great accuracy toward one or the other of the two open- ings. The distribution of the sporangia about the openings varied in about the same degree as in the case just mentioned; and in the same way, the sporangia which are outside the vertical strips con- taining the openings are mostly within 1 cm. of one of the openings. The reaction of Pilobolus when stimulated simultaneously by lights of different wave-length The problems connected with the simultaneous stimulation of an organism by light rays of various wave-lengths offer an interest- ing field to the investigator. But I know of no way of accurately comparing lights of different colors as to the total amounts of 107 JOLIV ETTE—PILOBOLUS 1914] fee ae Pebobebubeked ab ele lets bce SI T |''"|4r [LE rz |€ go fe le iP ler ig ee Pe ee eee v1 Bem tee Meee acacia | ee On te | 99 er Sade a 8 1G ee a ae eke I |gz jev jie ig |’) @ eer ZI S$ |or |bP Ihe IP gt |g€ |11 191 II xr |€ jer |Sx jor |¥ I tr ioe jz {1 16 or bv |ir j€€ jf |€ t/t 16. et ee 8 aire PII t |e sx |s € |sr lo |---|x os 8 eS: (hE 22 € j€xr |6O€ |rr jr bor 4 € |r je {Lr |gt joz jr |r SC Stee ie hs (Se 1G Bik. ae £vr 9 r je |2€ /€S |x jr 9 |vr |6 |z 2&1 s 9 |oz {2 Sgt ee 16 18S ig te gt iy pea beige PEF DP cceas) coral age 2 oz ¢ AOE UP chee ee lee eet es £9 tf a I |Or |r or I Wee ee oe le eres iy set sy gt quowtiedx9 jo roquny TROL ‘aoeds ouo snjd sain3y AAvay 79q di ba ssurued Il GIavL 108 BOTANICAL GAZETTE [FEBRUARY radiant energy. The following experiments, therefore, are qualita- tive only; but I hope they will prove suggestive. The different colors of the spectrum are represented in different proportions in the various incandescent lamps. These filaments are of standard make and the energy of the bulbs is measured in candle-powers. Thus by using bulbs of equal candle-power and current of known intensity we shall have somewhat comparable quantities. Although this method is not all that could be desired, it has a very marked advantage over the colored solutions used by SACHS, and also the monochromatic glass plates that are so generally used in work on the effects of rays of various wave-lengths. The colored solutions absorb a large portion of the total energy emanating from the source, different solutions differing in this respect. In the case of the solutions (and it is also true of the colored plates) : neither the intensity nor the energy of the lights can be compared. The incandescent lamps offer at least the advantage that they are of nominal commercial value; and with the advent of the knowl- edge of methods of comparison of intensities of colored lights, some exact idea of the intensities in the different parts of their spectrum may be obtained. Some study has been made to determine the distribution of the different wave-lengths in the different incandes- cent lamps, but so far it is insufficient for the present instance. It is known, however, that of the three incandescent lamps used in the experiments, the tungsten has the largest proportion of the actinic rays, the tantalum next, and the carbon least. The results with these filaments may thus serve to check up with those of the earlier work, in which the solutions and the plates of colored glass were used. Experiments were made in order to test the relative efficiencies of different incandescent lamps in bringing about the reaction of Pilobolus. In these experiments the carbon filament, the tantalum, and the tungsten were compared. The experiments were per- formed in the dark room, using the redwood light-proof box already described. The openings were 1 cm. in diameter and the distance between them from center to center was 1o cm. The culture was placed 23 cm. from the point midway between the two openings. 1914] JOLIVETTE—PILOBOLUS 109 The entire surface{of the culture, which was 5 cm. in diameter, was exposed. Before each of the openings, at equal distances, was placed one of the two lights to be tested. The angle at which the lamps were placed was such that the spot of light from each lamp struck symmetrically the open surface of the culture. The series of experiments was begun with a 32-candle-power carbon filament lamp before one opening and a 20-watt tungsten before the other. The first experiment gave a total of 92 sporangia; 31 sporangia were discharged toward the carbon filament and 61 toward the tungsten. In the second experiment 163 sporangia were discharged; 68 toward the carbon filament and 95 toward the tungsten. In the third experiment 387 out of a total of 784 spo- Trangia went to the tungsten. Of the 1116 fired in the fourth experi- ment, 113 went to the carbon, 1003 to the tungsten. The next experiment shows a total discharge of 228 sporangia; 78 toward the carbon, 150 toward the tungsten. A new carbon lamp was put in the place of the old in the seventh experiment, but again a very much larger percentage was aimed toward the tungsten; 589 spo- Tangia were fired, the ratio standing 168 toward the carbon as against 431 toward the tungsten. The data for this set of experi- ments are given in complete form in table IV. From this table a comparison of the accuracy of aim of Pilobolus toward the carbon and tungsten lamps can be made. TABLE IV g ro) ' 3 q os Total | s me #8 ¥ 7m hp g° ONUSGCR CAR eee ie 92 |.. Cotas ran Gatne ae ee Io} 6 3) 7) 42! 9 ra oe ae) Re, eae nek A Ee OP gh oe eee | Oy Oe arene rj} |} 3} 15) 54) 20)-. is Po i te a ee hae 6 | 64|203 | 86] rs} 6 | 4 | 2| 2| 5 | 3] 40| 253] 88) 3 dt As io a eee ae eee 3 | 19] 69| ro} 3/..., 2 | 2| 3 | 5 | 17|270| 607|\179| 18 804 Tkerews -| 15] 47 | 12 4 4 6| 22] ror) 17 ~ =a oa Bias r}...| 30/13] 21} 7) 1 | 2/2} 9} 58 503/130 41 tes|ese 1 | 7 | 48) 78) 24) 31 4] 2|3| 6) 8] 8| 69) 258 63) 4) 1 | 2 es ee en A i ee Of the 31 sporangia discharged toward the carbon lamp. in the first experiment, 19 (61 per cent) struck the glass over the tem. vertical strip containing the opening. Of the 61 sporangia I1O BOTANICAL GAZETTE [FEBRUARY discharged toward the tungsten lamp, 49 (80 per cent) struck within the corresponding strip. In the second experiment, of the 163 sporangia discharged, 68 were discharged toward the carbon filament, 47 (69 per cent) striking the 1-cm. strip over the opening; 95 were discharged toward the tungsten, 54 (56 per cent) on the strip over the opening. In this experiment, unlike the first, the larger percentage struck the strip over the opening in the case of the carbon filament. In the third experiment, 387 sporangia were discharged toward the carbon; 203 (51.7 per cent) of them in the vertical strip con- taining the opening; 397 were discharged toward the tungsten, 253 (65.2 per cent) on the region of the opening. The fourth experiment shows 69 sporangia, which is 61 per cent of the 113 sporangia discharged, toward the carbon, on the 1-cm. strip containing the opening; and 607 (61 per cent) of the 1003 sporangia fired toward the tungsten on the same region. The remaining experiments of this series all show greater accu- racy in the tungsten light than in the carbon filament light. With one exception, that of the second experiment, the discharge of the sporangia is more accurate toward the 20-watt tungsten used than toward the 32-candle-power carbon filament lamp, although the energy of the tungsten lamp is only half that of the carbon Jamp. Again, the percentages which strike the openings probably do not at first glance appear remarkable, but on noting in the first experiment that the 12 sporangia that did not strike the opening in the case of those fired toward the carbon light were all within 1 cm. of it, the accuracy is striking. Of the 19 sporangia which failed to strike the opening before the tungsten lamp, 16 were within 1 cm. of the opening and the remaining 3 were within 2 cm. of the opening. In the second experiment, 21 of the sporangia fired toward the carbon light missed the vertical strip containing the opening; 17 of that number were within 1 cm. distance of the strip. Of the 41 sporangia that missed the opening in the case of those fired toward the tungsten, 35 struck within 1 cm. of the opening. In the remaining experiments, most of the sporangia which failed to reach the opening in the strips fell within the first 1-cm. 1914] JOLIV ETTE—PILOBOLUS Iit strip on either side of them (table IV), showing the remarkable precision with which the sporangium is thrown toward a light. A series of experiments was made to test the relative efficiencies of a tungsten and a tantalum lamp in bringing about a reaction of Pilobolus; 40-watt lamps of each kind were used. The tungsten was placed before the left opening, the tantalum before the right opening at a distance of 40 cm. TABLE V _ dl 83 EF Total ZF cid gg BS = al 373 |---| I |...| r }...| 12] sol 137] 56] 25] rol xi 3/13] 2| 6 as! St} t7| St ON Peislee tivatis th Bal I5|T0o| 243/100] 32) 5 4/514 5) FOL 34): 34), F713) S MOE Peele teeshe fe) eal Pat eS) 4 31475 1° Sb ap-a8) gol 25) 2 32m j...|-..]...]...]...1 7] 36] xogl 42] si. rg eee ed cee Se a ee ee BOs foe eter | eh os] 6x eae Aa | ane, ae ed a Tf. Al 3S SQL a Be hes ta) 218 t) 8h 361 6 B58) SOR Ete ee en LL ee 688 |.. --| 3] 20}112] 291/102] 19] 6) 2| 2| 2| 2] 5] 20] 47] 24 836 <++f SO|T76| 3O3|tg8| Sri go]: xr] 4 | 2 | S| t| %4]. 22) OF 2} EF 4--- 574 3 5] 15} 69] 248) 53] 18} 2} x}... I} 5] 24) 43) 23) 2) t) ft togt |...|...|...| 6 | 20] 46/156] 354|164) 46| 21) 8| 7 | 8 | 13) 20] 40] 14%) §1| 15] 5 |... 464 |...) 2) x] 5{ a} 2x! 8x] 266] 71| 20] t7| 31213] 3 8 27, 9 old He BOF cl ---| 3] 17] 82| 143] 28] 25| rs} 7) 1 pee ae eed ad In the first experiment, 373 sporangia were discharged on the glass, 294 toward the tungsten and 79 toward the tantalum. The second experiment showed a total number of 628 sporangia, with 516 and 112 toward the tungsten and tantalum respectively. The number of sporangia discharged in the third experiment was 206; of these, 118 were fired toward the tungsten and 88 toward the tantalum. The total number of sporangia in the fourth experi- ment was 321, 197 and 124 being fired toward the tungsten and tantalum. In the fifth experiment, 185 were discharged, 130 toward the tungsten and 55 toward the tantalum. The sixth experiment also showed a larger number had been fired toward the tungsten. The data for this set of experiments are found in table V. The accuracy of aim toward the tungsten and the tantalum lamps was compared as in the preceding experiments. In the first. experiment 46.6 per cent were discharged toward the tungsten, 39.2 per cent toward the tantalum. In the second experiment the 112 BOTANICAL GAZETTE [FEBRUARY percentages fired toward the tungsten and tantalum were respec- tively 47 and 33.5. The third experiment shows 60.1 per cent before the tungsten and 44.3 before the tantalum; the fourth, 52.7 and 49.1 respectively; the fifth, 46.9 and 43.6; and the sixth, 48.9 and 44.8. The tenth and twelfth experiments show slightly larger percentages on the opening before the tantalum. The percentages figured out for the numbers striking either opening are given in table VI. The larger percentages strike the opening before the _ tungsten in these experiments. Most of the sporangia missing the opening strips in these experiments were found in the adjacent I-cm. strips, as was the case in the foregoing experiments. TABLE VI Numbe: P. t = Numbe P t: Percentages so foe | eee rs eee ee experiment tungsten lamp | tantalum lamp experiment tungsten lamp | tantalum lamp to 46.6 39.2 7 ag oe eee 44.3 42.7 Se ere eee 47 33-5 Bo ess 41.3 Be ic ees 60.1 44.3 Bee 59-5 4 Be Oye Sou 49.1 i ie nee ore 42.9 47.6 eae eae 46.9 43-6 i Catteni sce At] 40.9 Oe scccen oe, 48.9 44.8 OCR ae 44.2 50.7 In the next series of experiments a 40-watt tantalum was placed before one opening and a 20-watt tungsten before the other. The total number of sporangia fired in the first experiment was 1004; 731 were on the half of the glass toward the tantalum and 273 are on the half toward the tungsten. The second experiment shows a total discharge of 407 sporangia, 329 on the tantalum as against 78 on the tungsten. The third and fourth experiments both show larger numbers on the.tantalum. The data for this set of experiments are found in table VII. The accuracy of aim toward the two lights may also be obtained from the data in this table. Of the 731 sporangia discharged toward the tantalum lamp in the first experiment, 420 (54 per cent) struck the 1-cm. strip containing the opening. Of the 273 fired toward the tungsten, 149 (54 per cent) were on the corresponding strip. In the second experiment, the number of sporangia fired toward the tantalum lamp was 329; of these 161 (49 per cent) were in line with the opening. The total toward the tungsten was 78, with 37 1914] JOLIV ETTE—PILOBOLUS 113 (47 per cent) on the opening strip. In the third experiment, the ratio of the percentages of those on the 1-cm. strip containing the opening, in the case of the tantalum lamp, to that on the correspond- ing strip in the case of the tungsten is as 57 to 61. In the fourth experiment the accuracy of aim is very nearly the same toward the two lamps, although a greater proportion of the total number favor the tantalum lamp. The comparison of a 40-watt tantalum lamp against a 20-watt tungsten shows that a larger number of sporangia are discharged toward the tantalum, but that there is very little difference as regards the accuracy of aim toward the two lamps. 7 As in the set of experiments last described, a close examination of the data (table VII) reveals the fact that most of the sporangia that missed the vertical strips containing the openings were found within 1 cm. of them. An average of 7.8 per cent struck the glass more than 1 cm. laterally from the opening. © TABLE VII = FI : t Total 3§ 22 Ba Bs a o” + nun TSO sang casa eater micacer Weer ican SJ Pe fee ils evicted a 1 01887 420/IIO) 3%) It) 5 |I0 | § | 3 | 12) 40/149 s3| 3 |... | ae 407 s++]e+-/.-.]..-| 3 [ 80] 16x] 40] r2] 7} 51515131 3 37 | 13 125 toelessfeesfeee[o.-| 181 gO] ro] 2 TSE Wc ste t ttt Nees Oe te Ey... 4 38) BERT a8 s eet 5 23| 45 | 15] | | | a! A 40-watt tantalum lamp was next compared with a 32-candle- Power carbon filament with the results shown in table VIII. The first experiment gave a total of 96 sporangia, 36 of which were dis- charged toward the tantalum and 60 toward the carbon. The second experiment gave a total of 231 sporangia, with 164 fired toward the tantalum and 67 toward the carbon. In the third experiment 365 sporangia struck the glass, 268 over the tantalum and 96 over the carbon. In the fourth experiment, of the 157 spo- Tangia fired, 98 were on the glass over the tantalum and 59 over the carbon. The fifth experiment showed a total discharge of 1039, se pe found on the glass before the tantalum, 465 before the n. In the remainder of the experiments, as can be seen from 114 BOTANICAL GAZETTE [FEBRUARY the data (table VIII), there is a larger percentage of sporangia over the tantalum. Thus, with the exception of the first experi- ment, the number discharged in the direction of the tantalum lamp surpassed that discharged toward the carbon. TABLE VIII o 4 o i a3 aN 3s = Tota 25 gS #3 23 aT ee) cal 1S) 3 23) 5 Z| 0] 40) 0]: bes 231 43| 79\ 34 poe Ae 3] 2) 17) 32) 13)---]-- 305 65 136 401 FS 4) ah. s1 op 28). -48l x4 Shes 157 24) 57} 14) 2] I 1] 6] 4o| 1 re bers pe 1039 7|\116| 323|107| x5| 3] 2] 2] 2) xl rs! ox} 24aizos|. 8}... -|--- 76 I} 2 25| 1 3 at 6p ayy 6) eee 4 I} 35) 164 29 ai Xt 2b 26/230) 3T]3 fan W975 2 1-B ak 2| 3) 36/164) 748170} 31; of] 6] rl 5! xxl 26/106) 283/135) 20) 1O\ 5 r 100 7| 47| 11| 1 I 23] 4. ee sees 507 5) 5) SG 358) SOLS ay EE OF EE SEES] SE) 331) 40) 3 te 1442 |....]...|...] 1} 3] 8/208! s33i246| 24] 8 2| 7| 6| 28] 85| 183| 63| 6 3 a 813 \5/11| 4 | 4 | 10] 15) 20) 58] r78) 77] x5| x5] x7] 16] 18] 25| 31| 65| 93| 71/ 18] 18] 9 | 5 |21/4 174 1| 3) 20). 44 2 a) 4) 39) sh go} 22 Be 240 t 20) gs} 18} «| 1 coebee, Hc St ger ee t7bo4 ase tz} 69) 17} 1 Deere | ee ae 104 Tol 61 17| 3) Io} 2 tas 184 Ig} IOI 19] 1 7, 28 iat 19. 22} 62! 27| x 6| 55] 2 I ae 123 Tal 35 a) XO} 642) 54): - foe hp 231 -|.--[.--] 21 14] 4o|1x8] 266)162| 40] 18) 2} 2| x} 2| sojr22] 257/107| 42} 9) 3 |---| * 44 SEO Ab Tp ee te oe EL RRL ABS ee ee 43 ss ae Ll eet Si ee ears proses res 561 6} G8) t46) 35) 5) S| SP a} ot 2] 81 56] 32a) 44) 7]: 21. eae Of the 36 sporangia discharged in the direction of the tantalum lamp in the first experiment, 23 (63.8 per cent) struck the glass within the r-cm. strip containing the opening. Of the 60 sporangia fired toward the carbon, 40 (66.6 per cent) struck within the 1-cm. strip containing the opening. In the second experiment, 79 (48-2 per cent) of the 164 sporangia that are discharged toward the tantalum are found in the r-cm. strip over the opening; 32 (48 per cent) of the 67 discharged toward the carbon are on the corre- sponding strip. In the third experiment the percentages which strike the glass on the 1-cm. vertical strip over the opening before the tantalum and carbon filament lamps are respectively 50.7 and 50. In the fourth experiment 58 per cent of the sporangia fired toward the tantalum and 67.7 per cent of those fired toward the carbon filament lamp strike the strip containing the respective openings. 1914] JOLIVETTE—PILOBOLUS Tis The above percentages striking the area of the r-cm. opening before each of the two lamps compared are given, together with those computed for the remaining experiments, in table IX. The complete data from which the percentages were figured are found in table VIII. TABLE IX PERCENTAGES OF THE TOTAL NUMBER OF SPORANGIA DISCHARGED TOWARD THE TANTALUM AND CARBON FILAMENT LAMPS WHICH STRUCK THE I-CM. VERTICAL STRIPS COVERING THE OPENING IN EACH CASE IN EXPERIMENTS 1-23 IN TABLE VIII Number Percentage Percentage Number Percentage Percentage of before before of ore ore experiment tantalum lamp | carbon lamp experiment tantalum lamp | carbon lamp 1 aera Py eS I 63.8 66.6 PRU ees 49.3 34.8 eras eae 48.2 48 se netrnt sc 68.3 52.7 i EEE ey 50.7 5° «dee 60.2 69.2 EE 58 67.7 16. 248 68.5 66.7 eo 68.1 52 Lee eee 78.5 63.1 eee 55.5 58 ae eke 55.3 67 1 Pees 71.2 63.2 G6 oes 63.6 61.8 Boras 63.8 47 a ees na 32.6 43.1 ee eee 71.2 67.6 Bose ea 63.3 78.5 chin ree 57 54.2 7 ene Se 92.7 52.3 Le eae are 52:4 47.6 Canes 45.6 50.4 sie FS ae 41.7 a4.2 Average. . 58.6 55-9 ee In this set of experiments the accuracy of discharge varies con- siderably. In some cases the discharge toward the tantalum is more accurate; in others that toward the carbon lamp is more so. On the whole, however, the discharge is a little more accurate toward the tantalum, but the difference is so small that it is prac- tically negligible. From the percentages in table IX, it stands out clearly that wherever there was a small percentage which struck the opening before one lamp, there was usually a comparatively small percen- tage on the corresponding area before the second light. In the first experiment, 63.8 and 66.6 were the percentages striking the two openings. In the second experiment, 48.2 and 48 per cent struck the openings. In some cases there is less uniformity. The eighth experiment shows 63.8 per cent on one opening and 47 Per cent on the other. But on the whole, a small percentage on 116 BOTANICAL GAZETTE [FEBRUARY one opening is usually accompanied by a corresponding percentage on the other. It might be suggested that this may be due to the general condition of the culture at the time of the experiment. The accuracy might be affected by food supply, moisture, temperature, and other factors of importance to the physiological condition of the sporangiophores at the time of stimulation. Here, as in the previous experiments, the sporangia that strike outside of the opening are to be found for the most part in the first _ vertical strips to the left and right of the openings. An examination of the data (table VIII) will show a good proportion of the cases where all that were fired toward a single light are found on the opening or adjacent strips. Thus it is clear that the accuracy is much greater than it would appear from an examination of table IX alone. Summary Physiologists, in studying the reactions of plants to stimuli, have for the most part worked with phototactic organisms oF organisms of considerable complexity, individuals in which there was a differentiation of tissues, where the cells in one portion of the body may receive a stimulus, another perceive it, and still another respond to it. Such a study has the disadvantage of dealing with too many factors and accompanying phenomena. In Pilobolus the reaction is marked and can be easily studied. A single cell receives the stimulus and responds to it. The protoplasm of the cell receives the stimulus, perceives it, and reacts. The accuracy of response of Pilobolus toward the light is, remarkable, when we consider its size and the distance through which it throws its sporangia. The sporangiophore scarcely ever exceeds 1 cm. in length, and is usually somewhat shorter, while the distance through which it discharges the sporangium in most of the experiments is over 25 times that measurement. The accuracy of response and the nicety of organization of such a mechanism can well be appreciated from the study of such experiments. From such work the capacities of a single cell can best be realized. The results of the experiments in which Pilobolus is stimulated simultaneously by two lights bear directly on Nott’s (4) theory 1914] JOLIVETTE—PILOBOLUS 117 of “heterogene induction.” According to Nott, the reaction of an organism to one of two stimuli excludes the effect of the second stimulus. His work was concerned with two very different kinds of stimuli, light and gravity. The reaction to the stimulus of light excluded any response to the stimulus of gravity. Recent workers, GUTTENBERG (2) and Ricuter (5), have interested themselves along the same lines. GuTTENBERG maintains that if the light stimulus be diminished’ sufficiently, a resultant reaction between light and gravity will occur; that Nott and the earlier workers had used light that was too intense. To RicHTER’s (5) criticism that his results were due to impure air, GUTTENBERG (3) responded by further work under improved conditions and reached essentially the same results as before. In experiments on simultaneous stimulation of Pilobolus by lights of the same kind or of different kinds, we are dealing, unlike either of the foregoing cases, with simultaneous stimuli of one Kind, namely, light alone. It was possible to have the stimuli at least approximately equal, and it was possible to have the arrange- ment such that neither source of stimulation had any advantage over the other. Further, the organism worked with was a simple one, the reaction concerning only a single cell. And the net result of the reaction was shown so plainly in the distribution of the dis- charged sporangia that it seems impossible that any indefinite- ness or uncertainty could be entertained as to the reaction. The sporangia clustered always about one or the other of the two Sources of illumination. There was no sign of a resultant reaction. Even if the individual sporangiophore did not receive equal illumina- tion from the two openings, if there were any resultant reaction, it would be expected that the sporangium would be found in a position between the two lights, depending on the ratio of their intensities, differences of composition, and the like. Thus, it would be expected - that all of the sporangiophores would be located between the two sources of illumination. Such a condition did not obtain in any case where the two light stimuli were used, whether or not they were the same as far as distribution in the spectrum was concerned. The Sporangiophore reacted to one or the other of the two stimuli. The results obtained at least suggest that one stimulus does not 118 BOTANICAL GAZETTE [FEBRUARY affect the reaction to the other. To this degree the results are corroborative of Noti’s theory. But Notw’s theory, based on his work with light and gravity as stimuli, suggests a change of geoto- nus due to the presence of the light. In working with the two light stimuli, the reaction to one of the two stimuli to the exclusion of the other cannot be explained in this way, although here, as above, the plant is subjected to two directive influences. Where the two simultaneous stimuli were of different kinds, gravity and light, Nott believed that light may call forth certain changes in the plasma which, directly or indirectly, cause the reac- tion. He says that perception and reaction may rest on entirely _ different characters; but the reaction may be carried out by the same changes. In work where the two simultaneous stimuli are of the same character, as in the present experiments, the reaction is less complicated. Thus but two sets of changes of the plasma need be concerned with the response. The above experiments show that there is no sign of a resultant reaction, but that they can in no way determine whether, so far as perception is concerned, there is any influence of one light on the other. According to Noxt’s theory, a change of geotonus takes place, due to stimulation by light; that is, there is a change of sensibility to gravity as such due to the perception of light. The question arises whether, with the presence of two light stimuli of the same kind acting through the same time, there is a corresponding change of sensibility toward one light owing to the mere presence of a second of a similar kind. Apparently there must be some factor or factors somewhere in the organization of the plasma that brings about a total neglect of one stimulus and a complete reaction toward another of a similar nature, since the reaction is not a resultant one. It appears that Nott’s theory alone is insufficient to explain entirely the lack of resultant reaction to two directive forces when applied to an organism as contrasted with the results obtained by physicists in working with inanimate matter. The question, then, of what determines the reaction toward one light and a lack of response toward the second is still unsettled, and the explanation must be deferred to a time when more is known of the intricate mechanism and ultimate organization of the plasma of the cell. 1914] JOLIV ETTE—PILOBOLUS IIg In the experiment with the different incandescent filament lamps, as with the solutions and plates of colored glass used in the earlier work (1), Pilobolus fires its sporangia in larger numbers toward the lights in which the proportion of the blue rays is greatest. In other words, it is more responsive to actinic rays. The intensi- ties in the different wave-lengths, as earlier mentioned, are not measurable; but the uniformity of response in favor of the source containing the greater proportion of actinic rays suggests the superiority of the more refrangible rays over the less refrangible Tays in causing heliotropic curvatures. This question can be definitely settled only when the intensities of lights of different colors can be measured. The energy given off by the source of light apparently does not compare in effect with the distribution of the same in different por- tions of the spectrum. In the experiments using a 20-watt or 16-candle-power tungsten lamp and a 32-candle-power carbon fila- ment lamp the large majority of the sporangia went to the tungsten, although its total energy was but half that of the carbon. From this it is apparent that differences in distribution in the spectrum outweigh in effect the differences in the total energy of the two sources. The set of experiments using a 16-candle-power tungsten against a tantalum of twice the number of candle-powers showed the dis- charge to be in favor of the tantalum. At first glance it appears that this contradicts the above results with the carbon and tungsten lamps, and suggests that the total energy of the source does play asi important réle in the results. However, on further considera- tion, it must be noted that the total number of actinic rays in a tantalum lamp of twice the intensity of the tungsten is probably Sreater than that in the tungsten. The solution of this point, of course, is bound up with the question of intensity and composition of the sources under discussion and cannot be taken with any degree of finality. With the tungsten lamp of approximately the same intensity as that of the tantalum, the discharge was in favor of the tungsten which emits a larger proportion of the blue rays. The difference as far as distribution in the different wave-lengths of the energy of the tantalum and tungsten lamps is not so great 120 BOTANICAL GAZETTE [FEBRUARY as is the case of that in the carbon and tungsten lamps. This may account for some of the differences in the distribution of the spo- rangia in the two cases, when comparing the tungsten with the carbon and with the tantalum. A comparison of the carbon and tantalum lamps shows again a majority of sporangia discharged on the opening before the tantalum lamp which contained the larger proportion of blue rays. In the experiments with the rays of different wave-lengths, although the stimuli are both light stimuli, there is a marked dif- ference in composition. We have then an extra factor to deal with; but, as in the experiments with the two nearly equal light sources, there is no sign of a resultant reaction. There is no sign of a change of aim toward one light owing to the presence of a second light. With the tendency of the sporangiophores to dis- charge toward the blue light, however, it is plain that there is no uniform aim of all the sporangia subjected to the two lights to go to the light having the larger proportion of the blue rays. Why does not Pilobolus always discharge toward the source of light hav- ing more of the actinic rays? The difference in the length ot the light ray does bring a marked variation as regards the numbers fired toward the two sources. Still, some are fired toward the less favor- able of the two sources. The accuracy of aim toward the two lights might well be’ said to agree in general with that already found for the two light sources used in the above experiments. However, there is a noticeable difference in accuracy of aim toward the different filaments, and that for the most part is in favor of the light with the larger pro- portion of the more refrangible rays. With the solutions and glass plates used in the earlier work (1) there was a much greater difference noted. There is a probability that the smaller difference may be due to less difference in light intensity, to a smaller differ- ence in composition, and also that there is a limit to the accuracy of response toward any source of stimulation, and that in aiming at the lights in use in these experiments they reached that limit, the less effective lamp being sufficient, or in some cases nearly so, to bring about as accurate a reaction as is possible to the plant. 1914] JOLIV ETTE—PILOBOLUS 121 The question as to what properties of the protoplasm cause it to be more sensitive to rays of one wave-length than to those of another remains unsolved, and, like that as to why it responds to one of two stimuli to the complete exclusion of the other, it must await a better knowledge of the organization of the plasma. LELAND STANFORD JUNIOR UNIVERSITY CALIFORNIA LITERATURE CITED 1. ALLEN, R. F., and Jotivetre, H., Some light reactions of Pilobolus. Trans. Wis. Acad. Sci. 1912. . GUTTENBERG, RitrEeR von, Uber das Zusammeénwirken von Geotropismus und Heliotropismus in parallelotropen Pflanzentheilen. Jahrb. Wiss. Bot. 45:193-231. 1907. . 3. , Uber das Zusammenwirken von Geotropismus und Heliotropismus und die tropistische prea in reiner und unreiner Luft. Jahr Wiss. Bot. 47:462~492. - NOLL, F. eee fst Leipzig. 1892. . Ricuter, O., Uber das Zusammenwirken von Heliotropismus und Geo- “Fopismus. nee we Bot. 46:481-—502. 1909. N on MORPHOLOGY OF THISMIA AMERICANA CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 182 Norma E. PFEIFFER (WITH PLATES VII-XT) The family Burmanniaceae, chiefly tropical in distribution, is represented by about 50 species in EUBURMANNIAE, 2 in CORSIAE, and 18 in Tuism1Ar. The geographical range of the first named group is by far the widest; its representatives are found in all tropical regions and extend into the temperate zone. In North America, they are found as far north as Florida, Alabama, and even Virginia. CorsIAE are reported for New Guinea and Chile. THISMIAE are represented by two monotypic genera, Glaziocharis and Triscyphus, recorded for Brazil, and by 15 species of Thismia, if zygomorphic forms are included. Thismia is subdivided into four groups, Euthismia, Geomitra, Bagnisia, and Afrothismia. The Geomitra and Bagnisia divisions had been described as separate genera by earlier workers, but have recently been included in the genus Thismia. To date, the follow- ing species.in this genus have been described in these regions: Thismia Brunoniana Griffith (21), Tenasserim; T. Gardneriana J. Hooker (z), Ceylon; T. macahensis B. & H. (Ophiomeris macahensis Miers) (27), Rio de Janeiro; T. hyalina B. & H. (Myostoma hyalina Miers) (28), Organ Mts.; T. Aseroe (1. Ophiuris) Beccari (1), Borneo and Singapore; T. Neptunis Beccari (1), Sarawak; T. javanica J. J. Smith (9), Java; T. Winkleri Engler (7), Africa; T. crocea Ernst (Bagnisia crocea Becc.) (1), New Guinea; T. episcopalis F. Muell. (Geomitra episcopalis Becc.) (x), Borneo; T. clavigera F. Muell. (Geomitra clavigera Becc.) (1), Sarawak; T. clandestina Miq. (Sar - cosiphon clandestina Blume) (12), Java; T. Rodwayi F. Muell. (29), Tasmania; T. Hillii (Bagnisia Hillii Cheesem.) (3), New Zealand; T. Versteegii J. J- Smith (12), Java. Of these, the first 7 are of the Euthismia type, the eighth is the sole representative of Afrothismia, and the rest are of the Bagnisia or Geomitra group. The distribution of these is seen to be prac- tically restricted to the Polynesian Malay region. In view of Botanical Gazette, vol. 57] [122 1914] : PFEIFFER—THISMIA AMERICANA 123 this, the finding in the Chicago region of a form closely allied with these last is of decided interest. Thismia (BAGNISIA) americana, nov. sp.—Herbae saprophy- ticae, tenerae, hyalinae, caulibus simplicibus erectis, radicibus elongatis glabris foliis bracteiformibus. Pedunculi uniflori, erecti vel curvati, o.3-1cm. longi. Flores subtiliter virides 0o.8- 1.5 cm. longi, circiter 6mm. diametro. Perianthii tubus superus, obovoideo-oblongus, ore constrictus, lobis 6, quorum interiores tres apice conniventes, calyptram 3-stipitatam formantes; lobi alterni equales sed liberi. Stamina 6, fauci affixa; intra tubum deflexa filamentis brevissimis, connectivis maximis membranaceis in tubum deflexum connatis; antherae biloculares, loculis parvis distinctis parallelis, rima longitudinale dehiscentis. Ovarium breve, latum, 1-loculare, placentis 3 parietalibus, in cavo ovarii a pariete solutis. Stylus brevis, crassus, apice trifidus. Ovula humerosa, minuta, anatropa. Fructus turbinato-cupulatus, peri- anthii circumscisse deciduo truncatus, margine parum elevato cinctus. Semina numerosa, parva, oblonga, albuminosa; testa tenuis, hyalina, reticulata. Embryo parvissimus, in albumine inclusus. Chicago, Ill., in open prairie, N. E. PFEIFFER. The plant consists of a white root system, from which arise erect simple floral axes. The roots are about 1mm. in diameter and vary greatly in length. The flowers are 0.8-1.5 cm. high, borne n an axis 0.3-1.0cm. high. The perianth tube is conspicuously G-nerved and with 6 minor nerves. The 3 petals, approximately equal in length to the 3 sepals, are connate at the apex. The mouth of the perianth tube is closed by a disk of tissue, with a central circular aperture surrounded by araised ring. To this ring the 6 stamens are affixed, and are united into a tube which hangs downward inside the perianth tube. This stamen tube, largely made of the broadened connectives, bears the pollen sacs on the Side toward the perianth wall. The inferior ovary is one-celled, with three placentae which Soon become free from the walls, appearing in a central plane as three free columns. The ovules are anatropous, numerous, and 124 BOTANICAL GAZETTE [FEBRUARY small. There are two integuments. The seed contains a few- celled embryo imbedded in a mass of endosperm. The entire plant is glabrous and white, save in the 6 divisions of the perianth, where free, and in the disk closing the perianth mouth. Here there is a delicate blue-green color, deeper in the raised ring about the aperture of the disk. Most of the plants have only this colored upper portion above the level of the soil, or of the surrounding moss, etc. The diameter of 5-6 mm. and a height above the soil of 4-6 mm. give an idea of the size of the flower. When the soil is carefully removed, the underground parts are found to be white and semi-transparent; they lie more or less parallel to the surface of the soil, at a depth of a few millimeters. There is no connection with other plants, although the roots of Thismia often lie in close juxtaposition with other roots. When the plant is so exposed (figs. 3 and 4), the flower plainly shows the typical THISMIAE structure; a tubular, 6-parted perianth, with the three inner members united at the apex. The leaves, as in other depend- ent Burmanniaceae, are reduced to white scalelike bracts, so closely appressed to the floral axis that they are readily overlooked. The material was first discovered in August 1912, in a small space along the margin of a grass field. The habitat may be described as a low prairie, characterized by such plants as Solidago serotina, S. tenuifolia, Rudbeckia hirta, Eupatorium perfoliatum, Asclepias incarnata, Iris versicolor, Acorus calamus, and A grostis alba vulgata; and on the soil itself Selaginella apus, Aneura pinguts, and Hypnum. Usually the Thismia grows in spots where the soil is not closely covered by Aneura and Selaginella, but it may be found occasionally among the moss (fig. 3). The little plant is evidently protected both against strong light and great transpira- tion; but its habitat is in striking contrast to that of most of the other species of Thismia, which are found in rich-loamed primeval forests, in regions of great rainfall. , The plants were watched for stages in development during August and the first half of September, to the time when some fruits were obtained. In the season of 1913, visits to the field were made weekly, with the result that flower buds were found on July 1, about a month earlier than the first observation of the previous season. 1914] PFEIFFER~THISMIA AMERICANA 125 The indications were that the underground parts had wintered over, although seed-germination may have occurred and been overlooked, since the flower is all that appears above ground. Earlier descriptions of the Burmanniaceae gave little attention to any but the gross features, which were in the main correctly interpreted. Until recently, the work in anatomy has been done largely by Jonow (25, 26) in A pleria setacea, Gymnosiphon refractus, G. trinitatis, and Dictyostegia orobanchioides. The saprophytic forms worked with have scaly rhizomes, from which the flower stalks arise directly, as in Thismia. The adventitious roots are reported as being simple, with corky endodermis and a single, greatly reduced vascular bundle of lignified, dotted vessels, arranged in two concentric rings about one central spirally thickened element. The rhizome is described as having a structure much like that of the root. The erect stem or floral axis is credited with having bundles showing distinct xylem and phloem in most forms. The excep- tions are A pteria and Gymnosiphon trinitatis, which have such small bundles that the differentiation is difficult to recognize, according to JoHow. Nevertheless, he reports all cells of the bundle as lignified. Recently Ernst and BERNARD (9~20) have added largely to the knowledge of the anatomy of different saprophytic forms. They have considered Thismia javanica J. J. Sm., T. clandestina Mig., T. Versteegii J. J. Sm., Burmannia candida Engl., B. Championii, Thw., and B. coelestis Don (B. javanica Bl.). In these forms, the vascular elements in the root are much reduced; in 7. javanica (10) the bast alternates with thin-walled parenchyma cells about a central woody area, which is separated from the former by paren- chyma cells. The xylem region is figured as consisting of as many #$ 13 vessels. The fungus occurs in these roots in a patchy arrangement, infecting one group of cortical cells and not another. In the uninfected cells starch is common. In T. clandestina and T. Versteegii (13), a similar situation as regards arrangement of vascular elements is found, but the xylem 'S not so conspicuous in amount. In the former species, there is but one subepidermal layer of fungi, in the latter two, the outer of which is the coarser. 126 BOTANICAL GAZETTE [FEBRUARY The xylem in Burmannia candida Engl. (16) is represented by but two spirally thickened cells in the central cylinder; occasionally there is only one, seldom three. In addition, there are parenchyma cells and phloem. B. Championii (16), in contrast to this, has a central cylinder largely made up of xylem elements, with no phloem evident. B. coelestis (19), a chlorophyll-containing form, shows a similar simple situation as to root anatomy. In all the forms investigated, the floral axis has well developed collateral bundles. The vascular cylinder is sometimes surrounded by a ring of sclerenchyma tissue, as in Burmannia candida and B. Championii. The endodermis is usually distinct. Some of the cortical cells contain raphides. In Burmannia candida some of the surface cells are much like stomata in form, with pores always - open. In B. coelestis, a chlorophyllous form, there are normal functioning stomata, in contrast to the usual lack in saprophytic forms. . In Thismia americana, superficial examination of the under- ground structures shows a relatively large number of buds in all stages of development. These occur not only on the main struc- ture, which would appear to be a rhizome, but also on the structures which are very evidently roots appearing at the base of the floral axis. On examination of prepared sections, it appears that the histology of the main structure and of these secondary roots is identical, even to the appearance of a cap at the tip. Because of this fact, these structures, whether primary or secondary, will be referred to as roots. It would appear in field material that roots originally secondary might later appear primary by the dying away of a portion which thus severs the connection with the mother plant. In the older part of a root of Thismia, there is evident a very conspicuous epidermis (figs. 7, 14). This consists of large cells, more or less protuberant, but not developed into hairs in any region. The epidermal cells, in contrast with the cortical cells below the surface, are hyaline. The layer of cells immediately below the epidermis is packed with the thick-walled, branching mycelium of a coarse fungus. In fresh material the mycelium 1914] PFEIFFER—THISMIA AMERICANA 127 appears brown. The septate hyphae are usually oriented with the long axis of the root, so that the cross-section of a root shows numerous cut ends (fig. 14), and the longitudinal section a more or less parallel arrangement of the interweaving hyphae (fig. 7). Below this single layer is a region of a varying number of cortical cells containing much finer, thin-walled hyphae. In these deeper parts, masses of protoplasm are frequently evident which strongly suggest the sex organs of some of the Peronosporales. These undoubtedly correspond to the ‘vesicles’ reported by JANSE (24) in Thismia clandestina (T. javanica J. J. Sm.), which he was inclined to believe asexually reproductive bodies. BRUCHMANN considered similar bodies in Lycopodium annotinum to be oospores of Pythium. In Thismia there are also bacteria, probably corre- sponding to JANSE’s “sporangioles” and ‘“‘spherules.’”’ All these. fungal parts are intracellular. A few cells outside of the endodermis are free from fungi. These contain raphides which are common throughout the plant body. The endodermis consists of a single layer of heavy-walled cells, larger than their neighbors. It encircles a region, probably con- ducting, of which only a few central cells (3-5) are spirally thickened (figs. 5, 6, 19). They are not lignified, however, and the spiral markings are very fine. Near the point of origin of a floral axis, the number of thickened cells is increased and lignification occurs. These vessels may be seen to connect directly with the vascular elements of the floral axis. The cells adjacent to these spirally thickened vessels do not show the dotted condition that Jonow Teported in the Burmanniaceae considered by him. On the con- trary, though they are somewhat elongated, they are nucleate and retain their cytoplasm. They are undoubtedly parenchyma cells, and so the situation is similar to that in Thismia javanica J. J. Sm. and other forms investigated by ERNST and BERNARD. In the outer part of the conducting region are seen a varying number of points of small cells devoid of contents (fig. 6). The arrangement is similar to that reported in other forms by JoHow and by Ernst and Bernarp. It suggests a radial arrangement, with these groups of cells probably reduced phloem strands without Sleve plates. 128 BOTANICAL GAZETTE [FEBRUARY The growing region resembles that in any root. In a few milli- meters at the apex there is a meristematic region of actively dividing cells. Then there is the region of elongation and differ- entiation. The origin of the different layers would seem to con- form to the general situation in monocotyledons, with distinct initials in calyptrogen, dermatogen, plerome, and periblem. This would be in contrast to the situation in Thismia Versteegii, where Ernst and BERNARD report a common initial for epidermis and root cap. In Thismia americana the tip region of the root is free from fungi, but the tissue formed is rapidly invaded by the mycelium from older parts. In no case was new mycelium seen to penetrate the epidermis and so enter the uninfected region, as reported by JANSE in Thismia clandestina (T. javanica J. J. Sm.). Compared with that of the root, the anatomy of the floral axis is complex (figs. 8-10). Here the vascular elements are arranged in a cylinder of 3-6 bundles. In the early stages the number is very apt to be 3; in the older axis, near the apex, there are divisions of the original bundles, giving a larger number, frequently 6. More may be seen where branches go from the original bundles. Each bundle consists of definite xylem elements and a mass of cells with slightly thickened walls (fig. to). The xylem is slower to appear than the latter, which are early clearly distinguishable (fig. 8). In mature parts, the small clear cells appear in the same relation to xylem as phloem usually does, but they show no sieve plates so far as can be determined. Nevertheless, it seems probable that these elongated cells function as phloem. The xylem vessels have lignified and spirally thickened walls and their number varies from 2 to 15 in each bundle. The large number, the conspicuous spiral thickenings, and the lignification, as well as the greater and more definite phloem development, are quite in contrast to the condition found in the root. | A single strand of a few xylem vessels and phloem cells supplies each of the bractlike leaves (fig. 11), which are very thin and rela- tively broad. There are also branches of the main cylinder sup- plying the floral parts and producing the conspicuous nervation of the perianth. There is no definite endodermis or pericycle in the floral axis, 1914] PFEIFFER—THISMIA AMERICANA 129 nor is there a ring of sclerenchyma about the vascular cylinder as reported for some other burmanniaceous forms. As might be expected, no stomata were found; the corollary of no air spaces follows logically. The floral axes appear to arise a short distance back of the tip of the root (figs. 4,20). The first external evidence of their develop- ment is a single small excrescence (fig. 20a). Later two growing points, usually point upward, are distinguishable. Growth is guite rapid and soon results in a first root and a floral axis (fig. 20), from the base of which other roots take origin (figs. 21, 22). In prepared material, the earliest stage in the development of the bud is shown in fig. 12. A region of rapidly dividing cells occurs below the epidermis in a somewhat arched mass. At this stage the main root itself is in such an undifferentiated condition that the endodermis and neighboring tissues are not yet distinct. In slightly older stages, a break is seen to occur between the cortical cells of the root and the growing cells of the endogenous branch, which now has a slightly lobed margin (fig. 13). At this time, the beginning of the first root to be developed may be seen (figs. 13, 19) as a mass of meristematic tissue to one side of the floral bud. By rapid growth the root overtakes the stem from which it originated, so that when the two structures have emerged a little beyond the boundary of the main root, they are about the same size (figs. 14, 15). At this time the floral part is still protected by the arch of primary root cortical tissue, but the root tip soon breaks through the cortex, becoming much the longer organ (fig. 16). A renewed Srowth of the floral axis and the development of other secondary Toots from the main floral axis (fig. 17) finally result in a horizontal Position of the first root, which had previously stood erect beside the floral axis. In the development of the axis, the rudiments of the bract leaves appear laterally (fig. 17). After elongation and the develop- ment of the leaves, the differentiation of the floral parts occurs (fig. 18). The perianth tube develops early. At the same time, the stamens begin their development. The ovary with its ovules Is late in appearance, a case similar to that in Orchidaceae. When 130 BOTANICAL GAZETTE [FEBRUARY the ovules are first beginning to be evident, the microsporangial tissue is well defined. There are, as usual, four microsporangia in early stages (fig. 23), which later fuse to form the two pollen sacs (fig. 28). The early stages show the stamens bent inward and downward, but not connected with each other. Later growth, particularly of the connectives, makes a continuous tube, which is, however, easily separated into the constituent stamens (fig. 28). This tube extends beyond the sporangia, which occur on the side toward the perianth wall. In mature stages the pollen grains are slightly oval. They are very pale, almost transparent, with a pale green cast, due to little bodies, probably fat, many of which also occur in the perianth . parts. The microspores are loose and free, not massed together as in pollinia of orchids. Before shedding, the generative nucleus divides (fig. 29). A granular mass in the spore suggests the presence of a prothallial cell, but failure to secure stages in the present investigation must leave this doubtful at present. The ovules, very many in number, develop on parietal placentae (fig. 24), which swing free from the ovary walls in the center (fig. 18). At this level ovules project on all sides of the placental column. In early stages the numerous primordia appear as in fig. 18. The fully developed ovule shows two integuments (figs. 26-27). It is anatropous, with a long funiculus. As JoHOW (26) and TREUB (30), and lately ERNst and BERNARD, reported, there is a conspicuous differentiation of a few of the nucellar cells at the base of the embryo sac. This seems to have no significance at present. The seed is minute, with a testa two cells in thickness. The outer layer is composed of large, almost transparent cells. The inner one is constructed of smaller cells, with more contents, often appearing oil-like. The seed has a very evident endosperm, with cells of relatively large diameter, and an inconspicuous embryo of a few cells (fig. 30). In all respects it seems to agree with the accounts of TrEuB (30) and JoHow (25, 26), the former of whom first correctly interpreted the endosperm. Mr:Ers, in 1866, declared that the seed of Myostoma contained no embryo. Later, GRIFFITH interpreted the entire content of the seed as embryo. TREUB, 1914] PFEIFFER—THISMIA AMERICANA I31 in 1883, found a weakly developed embryo of 3 or 4 cells in a mass of endosperm in Burmannia maburnia and B. javanica. Jouow, in 1885, reported a similar situation in B. capitata with a 1o-celled embryo, and in Afteria one with 4 cells. In Thismia javanica, Ernst and BERNARD (11) have found a more strongly developed embryo with 4-6 tiers of cells. Thismia clandestina (14) has a still better differentiated embryo, with a 3-celled suspensor above a spherical body, the outer cells of which are differentiated from the inner. T. Versteegii (14), a closely related form, has on the other hand a simple embryo. Thismia americana then would seem, in its embryo situation, to resemble this last species and forms like Bur- mannia javanica and B. maburnia. No case of polyembryony has been found, such as was reported by Ernst (8,20) in Burmannia coelestis Don, a form developing embryos apogamously. Here the number of embryos was one, two, or three, dependent on whether the egg alone functioned, or the synergids were also active. In the earlier history ERNST found no reduction division to occur in the formation of ““mega- Spores.” Stages have not yet been obtained in Thismia americana to work out the sequence here, but assuredly, at maturity, only one embryo in each seed has so far been found. The arrangement of parts in the flower seems such that insect pollination would be necessary, unless a situation similar to that in Burmannia candida Engl. and B. Championii existed. Here the pollen grains germinate in the sporangia, and the pollen tubes Stow toward the style branches. No indication of this condition was found in Thismia americana. Up to date, the few attempts at germinating the tiny seeds have been fruitless. It is to be hoped that a larger harvest may give a better opportunity for positive results. The relation of the fungus inhabitants to the developing plant might be better worked in this connection than with the mature plant. Since the fungi occur in the root, the absorptive region, and not in the stem, they would seem to have some connection with water and food supply. Microchemical tests show that in the root there is a very large Supply of reserve food in the form of oils or fats. Contrary to the results of Ernst and Jouow, no sugars or starch are present in 132 BOTANICAL GAZETTE [FEBRUARY large enough amounts to detect by microchemical means. As indicated above, large amounts of calcium oxalate are present in the form of raphides throughout the parenchyma tissues of the plant body. This is probably to be related to the presence of the fungi. The green oil-like bodies in the perianth parts gave in spectro- scopic tests an absorption in the blue band. The coloring matter is not easily soluble in alcohol. Further features in the morphology and cytology of this plant will be presented in a later paper. Summary 1. The characters of Thismia americana are deemed sufficiently different from those of other members of the genus to warrant the description of a new species. 2. The main subterranean structure cannot be distinguished from a root, having a similar anatomical structure, including a root cap. ; 3. The root shows great reduction. The xylem is represented by 3-5 central spiral elements, the phloem by 4-6 small groups of cells. A radial arrangement is suggested in the grouping. 4. The vascular cylinder of the floral axis consists of 3-6 bundles, with xylem and phloem collaterally arranged. The xylem is composed of spiral lignified vessels. No sieve plates are dis- tinguishable in the phloem. 5. The floral axis and first root arise from the main root endoge- nously. Other secondary roots arise from the base of the floral axis bud. : 6. The ovary is slower in development than the other floral parts. Microsporangia are well developed when ovules first appear. 7. The ovules are anatropous, and have two integuments. 8. The embryo, consisting of a few cells, is imbedded in a mass of large-celled endosperm. The author wishes to express her thanks to Professor JOHN M. Coutter, Dr. CHARLES J. CHAMBERLAIN, and Dr. W. J. G. LAND, under whose direction this investigation was carried on. UNIVERSITY OF CHICAGO ror] PFEIFFER—THISMIA AMERICANA 133 al . = © 2I. LITERATURE CITED BECCARI, ODOARDO, Malesia 1:240-254. pls. 9-15. 1877. . BentHAM and Hooker, Genera Plantarum 3:455-460. 1883. . CHEESEMAN, J. F., Bagnisia Hillii Cheesem.; a new species of Burman- niaceae from New Zealand. Kew Bull. 9:419-421. 1908. . ENDLICHER, STEPHEN, Genera Plantarum. p. 163. 1840. ENGLER and PRANTL, Natiirl. Pflanz. 2:44. 1899. , Nachtrige 3:72. ENGLER, A., Thismia Winkleri Engl., eine neue afrikanische Burman- niaceae. Bot. Jahrb. 38:80-o1. jig. r . Ernst, A., Apogamie bei Burmannia pace Don. Ber. Deutsch. Bot. Gesells. 27:157-168. pl. 7. 1900. Ernst, A., and BERNARD, CHAS., Beitrige zur Kenntniss der Saprophyten Javas. I. Zur Systematik von Thismia javanica J.J.Sm. Ann. Jard. Bot. Buit. 8:32-36. pl. 9, 10. 1909.’ , II. Aussere u. innere Morphologie von Thismia javanica J. J. Sm. Ibid. 8:36-47. pls. 11-13. 1909. , III. Embryologie von Thismia javanica J. y. Sm. Ibid.8:48-61. pls. ee. 1909. ,iV. Zur Systematik von Thismia clandestina Mig. u. T. Versteegii J.J.Sm Ibid. 9:55-60. pls. 8-9. 1 Igit poe Vv: AR SM von Thismia tanita Miq. u. T. Versteegii JJ Sm. Ibid. 9:61-70. pls. 10-12. 1911. --—-——, VI._ Beitrige zur Embryologie von 7. sea ceca Mig. u. a. Versteegii J. J.Sm. Ibid. 9:71-78. pls. 12, 13. 19 ———, VII. Zur Systematik von Burmannia aids ‘Engl u. B. Cham- pionii Thw. Ibid. 9:79-84. pls. 14, 15. I9II. , VIII. Aussere u. innere Morphologie von Burmannia candida Engl. u. B. Championii Thw. Ibid. 9:84-97. pls. 16, 17. 1911. . Entwicklungsgeschichte des Embryosackes und des Embryos von B. candida Engl. u. B. Championii Thw. Ibid. 10: 161-188. pls. I3-I7. 1912. ,X. Zur Systematik von Burmannia coelestis Don. Ibid. 11:219- 222. pi. 17. 1912. ——, XI. Aussere u. innere Morphologie von B. coelestis Don. Ibid. 11: 223-234. pl. 18. IgI2. , XII. Entwicklungsgeschichte des Embryosackes, des Embryos, und des Endosperms von B. ¢oelestis Don. Ibid. 11:234-257- pls. 19-22. Igt2. Grirrirx, Wa., On root parasites referred to the Rhizanthaceae. Trans. Linn. Soc. 19: 303-348. pl. 6. 184 22. Hooker, J. D. , Flora British India 5:666. 1875-97- 23. Hooxer, J. D., and Tren, Henry, Flora —— 4:132. 1898. 134 BOTANICAL GAZETTE [FEBRUARY 24. JANSE, J. M., Les endophytes radicaux de quelques plantes javanaises. Ann. Jard. Bot. Buit. 14:53-201. pi. rr. 25. Jonow; Fr., Die agora Humus bewohner Westindiens. Jahrb. Wiss. Bot. 16:415-449. pls. . 1885. , Die chlorophyllfreien cat ae Jahrb. Wiss. Bot. 20:475-525. 1889. 27. Miers, JOHN, On a new genus of plants of the family Burmanniaceae. Trans. Linn. Soc. 20:373-382. pl. 15. 1851. ~ , On Myostoma, a new genus of the Burmanniaceae. Trans. Linn. Soc. 25:461-476. 1866. 29. MvuELLER, F., Notes on a new Tasmanian plant of the order Burman- niaceae. Bot. Centralbl. 45: 256-258. 1891. 30. TREUB, M., Notes sur l’embryon, le sac es et Vovule. Ann. Jard. Bot. Buit. 3:120-128. pls. 18, 19. 1883. 26. EXPLANATION OF PLATES VII-XI All figures, except 1, 2, 3, 4, 20, 21, 22, and 28, were drawn at the level of the table with the aid of a Spencer camera lucida under Spencer objectives 16, 4, or 1.8 mm., and oculars 2, 4, or 8. he following abbreviations are used: b, bud; dr. enki e, epidermis; fa, floral axis; ii, inner integument; 0, outer integument; /t, leaf trace; /, fungus infected layers; m, microsporangia; ~ mr, main root; 0, ovary; p, phloem; Y, perianth; pw, perianth wall; rc, root cap; s, style; sr, secondary root; s’r’, second ey root; x, xylem. Fic. 1.—Side view of plant of Thismia americana, in situ; X Fic. 2.—View of flower from above; petals cut apart ES apex vor folded back; 4.5 . IG. 4, “Aen from above of group of ain undisturbed in natural situation; the oldest flower appears at the right; IG. 4.—View from above of plants from aca the re has been removed; the white root portions are evident with their buds; x 2.6. Fic. 5,—Longitudinal section of central cylinder e root; xX 266. Fic. 6.—Cross-section of central cylinder of root; 66. Fic. 7.—Portion of root in longitudinal section, oe subepidermal fungus infected layers, and epidermis free from fungi; 2 1G. 8.—Cross-section of central region of young erect axis, showing early phloem development ; X2 Fig. 9— iagrammatic sroidenition of erect axis and bract leaves; the outlined portion of the proper is shown in fig. 10, of the leaf in fig. 12, with higher magnification; X35. IG. 10.—Detailed drawing of portion of cross-section of floral axis; one leaf trace supplies the next leaf; x 266. IG. 11.—Detail of — of cross-section of leaf, showing single, simple bundle; X 266. BOTANICAL GAZETTE, LVII PLATE VII PFEIFFER on THISMIA BOTANICAL GAZETTE, LVII PLATE VIII Nena € Phiffir ane Q 10 ¥ elle PFEIFFER on THISMIA PLATE IX BOTANICAL GAZETTE, LVII pra ot 2 ae pene rae _ t ! PFEIFFER on THISMIA PLATE X a a Ss n) Q ak om Q N as S S 4 Y pay be NN =) inal ® t I ' i} ! ' \ ! ! A hi. PFEIFFER on THISMIA | BOTANICAL GAZETTE, LVII PLATE XI 4 PFEIFFER on THISMIA 1914] PFEIFFER—THISMIA AMERICANA 135 Fic. 12.—Longitudinal section of tip of root, with young bud just develop- ing; its proximity to the root cap is striking; X52. 1G. 13.—Older bud, in which the floral axis and secondary root tip have begun to differentiate; outlined portion in detail in fig. 19; X 26. Fic. 14.—Cross-section of main root with secondary root; X52. Fic. 15.—Same main root, showing floral axis in neighboring section; Fic. 16.—Later stage, where secondary root has elongated more rapidly than floral axis; longitudinal section of main root; X52. FIG 17. Cross: section of main root, jongitidinal of floral axis, at base of which second secondary root is developing; X 52. Fic. 18.—Young flower in longitudinal section, showing arrangement of parts; X52. Fic. 19.—Detailed drawing (see fig. 13) to show relation of rudiments in bud; X27 : Fic. 2 —Early stages in development of root and floral axis, as seen in habit sania é, same plant as d seen from above; 4. Fic. 21.—Subsequent stages; X2. : Fic. 22.—Later stage, showing fruit; other floral axes arising on primary root and on secondary roo Fic. 23.—Cross-section of young flower, showing stamens; X 26. Fic. 24.—Cross-section of same flower through ovary; X 26. Fic. 25.—Cross-section of style of same flower; : IGS. 26, 27, es at megaspore mother cell stage; 835. G. 28.—Stamen tube removed from flower, as seen ger side toward scaaat big the pollen sacs have dehisced longitudinally; Fic pga eet before shedding; the generative cell eae to divide; remains a a prothallial cell(?) in one; 835. Fic. 30.—Embryo imbedded in endosperm; X 835. Fic. 31.—Seeds at maturity; 87. CONCERNING THE PRESENCE OF ‘DIASTASE IN CERTAIN RED ALGAE E. T. BARTHOLOMEW Introduction In most starch-forming plants the starch grains are deposited in the plastids. The work of both early and recent investigators shows, however, that this is probably never true for the red algae. In this group of plants the grains are described as being formed in the cytoplasm, outside the plastids and often apparently quite independent of them. In the red algae the grains, which resemble the starch grains of higher plants, do not usually give the customary blue color when treated with iodine or zinc chloriodide. In a few species, for example Lorencia sp., Polysiphonia nigrescens, and Ceramium tenuissimum,: the color with iodine varies from violet to almost blue, but in most species it ranges from light brown to wine red. There is such a wide divergence of reaction in the different forms tested that OLTMANNS? suggests the possibility that each species will be found to give its own characteristic color reaction. Saki’ found that by applying strong solutions of malt extract to commercial food preparations made from various red algae, such as Gelidium sp., Porphyra sp., and Chondrus crispus, no digestion whatever of the carbohydrates took place. From this and other experiments he concludes that the polysaccharid carbohydrates in these algal food preparations are not readily transformed into sugar by carbohydrate-digesting enzymes of animal: origin, and scarcely more so by vegetable enzymes or bacteria. Konic and Betrets* hydrolyzed, with acids, the carbohydrates in Porphyra sp., Gelidium sp., and commercial compounds com- * OLTMANNS, F., Morphologie und Biologie der Algen 2:148. 2 [bid. 3 Sark, T., The digestibility and utilization of some polysaccharid carbohydrates derived from the lichens and red algae. Jour. Biol. Chem. 2:251-265. 1906. 4 Konic, J., and — J., Die Kohlenhydrate der Meeresalgen und daraus: hergestellter Erzeugnisse. Zeitschr. Untersuch. Nahrungs- und Genussmittel 10: 457- 1905 ; Botanical Gazette, vol. 57] [136 1914] ' BARTHOLOMEW—DIASTASE IN RED ALGAE 137 posed of red algae. Their results showed the presence of galactose, fructose, and glucose in varying quantities. In carrageen (Chon- drus crispus), MUTHER and ToLtens: found galactose and probably other hexoses belonging to the fructose and glucose groups. The grains in the red algae often show the physical character- istics of the common starch grains of green plants as to hilum, striation, and effect of polarized light, but their place of deposition, their behavior toward iodine and zinc chloriodide; their sugar extracts, and their apparent resistance to the action of malt extract would tend to prove that they are not true starch. The grains appear and disappear at various times during the life of the plant, thus suggesting the presence of an enzyme which is an active agent in bringing about their decomposition. The following experiments were performed that further evi- dence might be gained as to the nature of the substance composing the starchlike grains in the red algae, by determining whether or not the diastase that acts on the grains in these plants will also digest the common starch isolated from the higher plants. So far as is known to the writer, this is the first attempt in this direction, and a preliminary statement of the results is herewith recorded. Material and methods I. SPECIES FROM WHICH EXTRACTS WERE MADE Polysiphonia variegata Ag., Dasya elegans Ag., Agardhiella @ (J. Ag.) Schmitz, and Ceramium® lent themselves most readily to experimentation because of their abundance and the fase with which they could be obtained. Grinnellia americana Harv., Griffiithsia globifera J. Ag., and Chondrus crispus (L.) Stack. Were also used and tended to show the same results as those obtained from the foregoing species, but sufficient quantities of the latter named plants could not be procured at the time of these experi- ments to warrant the drawing of definite conclusions. *Miruer, A., and ToLLens, B., Ber. Deutsch. Chem. Gesells. 37:298-305, 396-311. 1904 6 ‘ : Several Species were used in the same mass of material. 138 BOTANICAL GAZETTE [FEBRUARY 2. METHOD OF EXTRACTION AND gy cites OF FINAL PRECIPITATES The extracts were made according to modified Buchner and Litner methods. Fresh vigorous algae were taken from the sea water and quickly rinsed under the tap. The excess tap water was removed by filter paper or cheese cloth. The algal material was then immersed in 95 per cent alcohol for 20 minutes. Having been freed from excess alcohol, it was next plunged into acetone for 10 minutes. The excess of this solution having been removed, the material was placed in fresh acetone for two minutes, partially dried by suction, and placed in an oven at 35°-40° C. until dry. Upon being taken from the oven, the dried material was cooled in a desiccator, thoroughly pulverized, placed in three times its amount of 20 per cent alcohol, and left standing 18-24 hours. At the end of this period the substance was filtered by suction through a Buchner funnel lined with cheese cloth and filter paper (it was necessary to filter the material by suction because of its vis- cosity), and to the liquid thus drawn off was added two and one- half times its volume of 95 per cent alcohol. After being filtered as above, the precipitate was washed in equal parts of ether and absolute alcohol, dried in a desiccator, and after being pulverized the extract was ready for use. The extraction treatment did not remove all of the color, so that the precipitates varied from brown- ish to light red. Because of the difficulty experienced in filtering, the final pre- cipitates were probably far from pure, but the following figures will show the amounts of precipitates obtained from the different species: Polysiphonia variegata,. <<. : 21.00 grams ponder = 15 are fn re Ceramiim 2 on 51.00 e: —0.15 Dasya cans. 2. 53.03 = Cee Agardhiella tenera .......... st. 405°" ce ag Agardhiella tenera........... ti.00 eee ee * Obtained after material had been dehydrated, desiccated, and pulverized. 3. ALGAL EXTRACTS AND COMMERCIAL DIASTASE Solutions of various concentrations were made from the algal extracts, but the one giving the best results consisted of 9.93 gm. of extract dissolved in 5 cc. of distilled water. hte to the 1914] BARTHOLOMEW—DIASTASE IN RED ALGAE 139 nature of the extracts, solutions of this concentration were quite viscous. In most cases the viscosity would about equal that of a 75 per cent solution of glycerine and water. That a check might be had as to the time required for action and as to the final results, solutions of commercial diastase were also used. The solutions were of the same concentration as those of the algal extracts and . were applied and tested in the same manner in every case. Both Eimer and Amend’s and Merck’s diastase were used, with no apparent difference in the results. 4. STARCH PASTE Corn starch was used in all experiments. The paste used was made by adding 0.25 gm. of starch to 100 cc. of water and boiling 6 minutes. The boiling, though done slowly and in an Erlenmeyer flask plugged with cotton, probably caused 1o per cent of the water to be vaporized. No water was added to make up for this loss. New solutions of paste were made for each series of experi- ments: 5. CONTROL MEASURES To determine as far as possible all sources of error, the following control measures were taken: a) The “A, B, and C” parts of Fehling’s solution were mixed Just preceding each series of experiments. 6) Tubes of untreated paste were tested each time and in the same manner as those tubes containing the paste plus the extracts. : c) To detect any error due to the presence of an active agent * the distilled water, tubes of the paste were treated each time with distilled water only and tested in the regular manner. : 4) Toluol was used as a sterilizing medium, except in the Van Tieghem tests, in which 10 per cent alcohol was used. e) All containers and instruments were carefully sterilized with # strong solution of potassium bichromate and sulphuric acid. 6. TEST METHODS A. Digestion in test tubes The proportionate amounts of starch, algal extracts, commercial and distilled water used in each series of tests were as ollows: 140 BOTANICAL GAZETTE | [FEBRUARY Test tube no. 1-5 cc. starch paste plus 1 cc. algal extract sé “cc “cc 2-5 cc; ‘é 6é it Ic ce “ce “a eee. ero ee, commercial diastase “ce ce ce ce te “ce ce 4-5 CC. 2 cc. ek eh ner ace ae Se distilled water ‘“ ‘“ ‘ 6-5 cc. 3 ec 73 Bot Oe ee ee, wntreated age paste To ot eee OC, algal extra: solut eo ee Oe, Baa paceta ition When the experiments were to run for a longer period, the amounts were increased, but the same proportions were maintained. At the end of certain periods, indicated in the tables, 2 cc. of the solution were taken from tube number one and placed in two smaller tubes, 1 cc. in each tube. This process was repeated until test samples had been taken from each of the 7 tubes. One of each pair of small tubes was treated with iodine and the other with Fehling’s solution. The experiments were all kept at room tem- perature, which was rather low, the daily average being 18°6 C. B. Digestion in Van Tieghem cells To determine microscopically the effect of the algal extract upon unboiled starch, small quantities of dry corn starch were placed in four Van Tieghem cells. Three of these were treated with extracts from Polysiphonia, Agardhiella, and Ceramium, the fourth with distilled water to act as a control. 7. TERMS USED IN TABLES TO DESIGNATE COLOR REACTIONS AND AMOUNTS OF PRECIPITATES That the standard for the designation of iodine color reactions and for the amounts of copper precipitate might be as nearly as possible the same for each series of experiments, two sets of terms were adopted. These may be interpreted in the following manner by referring to PRANG’s Standard of colors (1898): IODINE COLOR REACTIONS As specified in tables As illustrated by chart t, Blue... oo. ee Plate I, 1-B 2. Tinge of mile Ue “1 eey 3. Dineen i ey he. SUEPIe ee es ae erie kOe ee we hai ee ee ge 5 oS i Ul, 1-V ree WONG ais ges ieee eae ee pe Fig 6. Very light purple... 1 a 7- WE oo a ce ae eta ee ee ee Caneel wee ee ens ag Vv; 5-0 $. Browse. ic « 17,078 1914] BARTHOLOMEW—DIASTASE IN RED ALGAE Fehling’s solution precipitates* ihe Ole e 60; 6 6 6.8 e oe ed si nl, net Gh, ak ee A ee ae es wee we) see 8 8 eS 8 used des: Algal extract Plate II, 6-OYO “ce + “ee ce i “ce ‘6 ‘é é 8 a) ee ele *Although the precipitates from the two different extracts were ignate, as nearly as could be estimated, equal amounts of the two precipitates. 141 Commercial diastase eee eee ee | eee eens e080 8a wl Plate I, 6-YYG of different colors, the terms These designations were of course only relative, but they served The colors designated in the tables were recorded within a few minutes after the application of the testing very well as a guide. reagents. Results I. DIGESTION IN TEST TUBES Tables I-IV were chosen promiscuously from a large number of tables, and are used as types to show the effect of the algal extract on starch paste and its rate of action in comparison with that of | commercial diastase. TABLE I EXTRACT FROM CERAMIUM AMOUNTS oF VARIOUS SOLUTIONS ee, T cc. algal extract 8 een ae CC. ee ae ee ae tay ea eM ithe TEL ee ea ath ee a ee eR ee we ee lib, ey Eee ae Control, 5 CC. starch paste. . extract A E ee ict Te ee eo Ce ae te eee ae eo AFTER Ir HOURS AFTER 24 HOURS : Amts. ppt. with + Amts. ppt. with Todine col A Iodine color " wding color |"Fehtingscolu- | Toding olor | Peking sau Tinge of : purple Trace Blue-purple | Slight Blue-purple | Slight Purple Small Light purple} Fair Light purple} Medium Very light purple Fair Light brown} Marked Blue None Blue None Blue None Blue None Blue None None Deel seeo wos None Seger tt ereeae ome Medium Medium ee ee ee oe 142 BOTANICAL GAZETTE [FEBRUARY The action of the algal extract is very slow when compared with that of commercial diastase, as is shown in the preceding tables I-IV. To determine whether the action of the algal extract would TABLE II EXTRACTS FROM POLYSIPHONIA VARIEGATA ? AFTER 12 HOURS AFTER 36 HOURS Amts. pi F es eth Boos Medium Medium Very marked ery marked AFTER 28 HOURS AMOUNTS OF VARIOUS oe = SOLUTIONS S. ppt. wi : lotie ake Fehling’s Pi tees olor ion ce. “spas pega wh 5 cc.) Tinge of Met PA ey. purple Slight Light purple a a aipal pea 5 ce i ATEN TONG oo ay cc Blue-purple | Small urple I cc. commercial diastase+5| Purple- ce. starch pastes. 20S, brown Marked Brown 2 cc. commercial diastase+ 5 ec. starch paste... 2... .5 Brown Marked Brown 1 cc. distilled water+5 cc. star fee ea Blue None Blue 2: ce, rps water+5 cc. BATCH DASE oo uae: Blue None Blue Control, 5 ot geen’ paste .| Blue None Blue 2c. algal e extract. 4530 os, ONG 5 ja ee ee, 2 cc, commercial diastase... .j... 0.5... .. Mean 5 7-:2 5 TABLE III EXTRACTS FROM AGARDHIELLA TENERA AFTER 16 HOURS AMOUNTS OF VARIOUS SOLUTIONS . Amts. ppt. wit ‘ Ting solor_| SEingsou: | Tong cole 1 cc. algal extract+5 cc. Tinge of starch paste; 0. 31a, e None purple 2 cc. algal extract+5 cc.| Tinge of starch peske.. i665 554% purple Trace Blue-purple cc. commercial diastase+5| Purple- cc. starch paste ........ brown Medium Brown cc. commercial diastase cc, starch paste... 502. rown Medium Brown I sae ee water+5 cc. eae Blue None Blue 2 pry ~ baie water+5 cc. st nee ice eee Blue None Blue Control, 5 cc. starch paste .| Blue None Blue 2 Oc. WitBbOSIIAch 4) oe NOME Oe ee 2 cc. commercial diastase...|............ Mechitny ioe gai oe. Amts. ppt. wi Febling $ a Trace Slight V 1914] BARTHOLOMEW—DIASTASE IN RED ALGAE 143 cease before digestion was complete, experiments were set up as before but allowed to run for a longer time. in table V. TABLE IV EXTRACT FROM DASYA ELEGANS The results are shown AMOUNTS OF VARIOUS SOLUTIONS AFTER 17 HOURS AFTER 25 HOURS cc. algal extract+s5 cc. cal | See Po — oe SCC: Were Onete. Po. commerical ets Oc. Statch paste... ... 2 Cc, commercial diastase cc. star ch Spigot 1s 4 eee gs a oe eel 2 0c. distilled water Control, 5 pas ie ‘sig ios oe —— paste . c. algal ex Spies ; ae Meetisiaioat ESE He Let, ee a eae a . Amts. ppt. with ee Amts. ppt. with ame | Relies | “aertee” | eee Blue None Blue ? Trace Tinge of : lue ? Trace purp. Very slight Very light purple Marked Brown marked Purple- ery brown Marked Brown marked lue None Blue None Blue None Blue None Blue None Blue None Cy ie Coe aes one oe, one Maples es DRO Medium Poe 1 ee OM eaten TABLE V EFFECTS OF LONGER CONTINUED ACTION OF THE ALGAL EXTRACTS AND THEIR COM- _—_ PARAT IVE RATES OF ACTION AMOUNTS oF soLUTION on 5 cc. OF STARCH PASTE AFTER 3 DAYS AFTER 6 DAYS Oe aes 2 cc. Agardhiella extract ... 3 cc. Agardhiella extract ... 2 cc. Ceramium* extract .- - 3 cc. Ceramium* extrac 2 cc. Polysiphonia extract . 3 cc. Polysiphonia extract ii : = ao ‘ eet Amts. ppt. with Todine col Iodine color cing color |" Fettng’s | Teding color "Fenn Purple Fair Very light | Very purple marked Light purple} Medium Very light | Very urple marked Tinge of : Very slight | Blue-purple | Slight Blue-purple | Slight le air -| Blue-purple Medium Very light | Very purple marked Purple Marked Very light | Very purpl ked Blue None Blue one lue None Blue None Blue Non Blue None SR ton’ nina 2 c Fal ttn at, +t, 144 BOTANICAL GAZETTE [FEBRUARY 2. DIGESTION IN VAN TIEGHEM CELLS ' The cells were examined daily and it was found that in those containing the starch treated with the algal extracts, very notice- able corrosion of the grains was taking place. The rates of digestion agreed very well with the tabulated results in table V, Polysiphonia and Agardhiella acting more rapidly than Ceramium. The results thus obtained in the first trial were confirmed by repeat- ing the experiment several times. Marked acceleration of cor- rosion was obtained by placing the cells in a warming oven at a temperature of 26° C. No corrosion could be detected in the control cells. Discussion That the disappearance of the starchlike grains in the living tissues of the red algae is due to the presence of some catalytic agent, which may be extracted and applied to corn starch and its derivatives with positive effects, is demonstrated by the results recorded in the foregoing tables. The action of this extract when applied to starch paste is very similar to that of commercial dias- - tase. This is shown by the fact that in both cases the digestion of the starch appeared to be a series of processes leading more or less gradually from the amyloses down through the dextrins until amylolytic action was complete. This is brought out clearly not only by variations in color, but also by the fact that often when the iodine would indicate a marked degree of change in the solu- tion, still the Fehling’s test would show the presence of but very little sugar. It would appear from this that the algal extract, like the diastase of the higher plants, is not one simple enzyme but a complex of amylases and dextrinases. Then, if we may argue from analogy, the grains in the red algae, commonly referred to as starch, are probably, as Meyer’ and others suggest, a combination of both starch and dextrins, or, as Btrscuir® thinks, possibly a transitional stage between amyloporphyrin and amyloerythrin. No direct evidence was obtained by experimentation as to whether or not this carbohydrate-digesting enzyme of the red algae 7 MEYER, A., Untersuchungen iiber die Stirkekérner. Jena. 1895- 8 Birscuut, O., Notiz iiber d. sogen. Florideen Starke. Verh. Naturf. Med. Ver. Heidelberg N.F. 7:519-528. 1903. 1914] BARTHOLOMEW—DIASTASE IN RED ALGAE 145 might also act-as a synthetic agent in forming the grains in ques- tion. BELzuNG? found that in some species the younger the grains the more nearly they came to giving the normal blue color reaction when treated with iodine. Hence, if this enzyme does act syn- thetically, it appears that, in some cases at least, the action is just the reverse of that which takes place in some of the higher plants, for example, in Piswm sativum, in which the erythrodextrins are formed first, the amylases not appearing until the grains are almost mature. The difference in rate of amylolytic action between the algal extract and the commercial diastase is very noticeable. This is already indicated in tables I-IV. This variation may have been due to difference in concentration. The algal extracts were known to be far from pure, and it was for this reason that solutions of rather high concentration were applied to the starch paste. Table V indicates that there is also considerable dissimilarity in digestive power between the algal extracts themselves. Here again is the possibility that this may be attributed to an inequality in purity, for the extracts did not all present the same degree of difficulty in filtration. However, the explanation is hardly to be looked for in this direction, for although A gardhiella and Polysiphonia extracts were more difficult to filter than was the Ceramium extract, yet the two former completed amylolysis in 6 days, while the latter required 9 days under the same conditions, as is shown in table V. As a result of recent experiments, ACHALME and BRESSON” maintain that diffusion is an important factor in the rate of enzy- matic action. They found that an increase in viscosity of the solu- fon meant a like decrease in the rate of action of invertase upon Saccharose, They also maintain that this is true for emulsin, trypsin, and for organic oxidases. As has been said, the viscosity of the algal extracts would about equal a 75 per cent solution of glycerine m water. That this condition influenced the amylolytic action os Sooo E., Recherches morphologiques et physiologiques sur l’amidon et € chlorophylle. Ann. Sci. Nat. Bot. VII. 5:223-228. 1887. ac , P., and Bresson, M., Influence de la viscosité du milieu sur les actions-diastasiques, Compt. Rend. 152:1328-1330. 1911; also Du réle de la vis- Cosité dans les variations de V’action de Vinvertine suivant les concentrations en Saccharose, pt. Rend. 152:1420-1422. 1911. 146 BOTANICAL GAZETTE [FEBRUARY of the extracts is not evident. It is true that the viscosity of the algal extracts greatly exceeded that of the commercial diastase and that action was very much more rapid in the latter than in the former; but this may have been due to some other factor, for although the extract from Polysiphonia was quite noticeably more viscous than that from Ceramium, yet the former completed diges- tion in two-thirds of the time required by the latter. Here, as before, we cannot draw definite conclusion, for there may have been a marked variation in purity between the two extracts. In some of the higher plants we find diastases that work very slowly, and it is not impossible that the algal diastases are also of this nature. It is a well known fact that by the addition of very small amounts of such substances as free mineral acids, neutral phos- phoric acid compounds, salts of aluminium, and asparagin salts, the amylolytic action of the diastase from higher plants is very much accelerated, and it might be mentioned here that small amounts of aluminium acetate and sodium.-chloride had the same accelerating effect upon the algal extracts. The Van Tieghem tests were of interest not only because they corroborated the macrochemical tests, but also because they showed that the manner of attack of the algal extracts was such that the starch grains were corroded. This would indicate that at least the most active enzyme present was a translocation rather than 4 secretion diastase. The contrast between the colors of the precipitates of the differ- ent mediums tested with Fehling’s solution was very marked. The precipitates in the tubes containing the paste treated with algal extract was of the usual “‘brick-red”’ color. Paste treated with commercial diastase gave a light yellow precipitate, eve? though the tubes were allowed to stand for a considerable length of time before the test was made. This would indicate the presence of some colloid which prevented the deposit of free copper oxide. The precipitate in the tubes containing the algal extract showed that whether or not the viscous nature of the extract retarded amy- lolytic action, there were no colloids or other substances present which prevented a free deposit of the copper oxide. 1914] BARTHOLOM EW—DIASTASE IN RED ALGAE 147 Conclusion and summary . There is present in the red algae a diastase which will digest the ech of higher plants. 2. The manner of action of this enzyme indicates that it is at least partially composed of a translocation diastase. 3. The diastase of the red algae, like that of the higher plants, is probably not composed of a single enzyme, but of a series of amylases and dextrinases. 4. Judging by the action of the algal extract upon corn starch, the diastase is a rather slow-working enzyme. 5. The series of digestion processes resulting from the appli- cation of the algal diastase to corn starch would indicate that the substance composing the grains of the red algae is very similar to that of the starch grains of higher plants. These experiments were begun at Woods Hole, Massachusetts, and completed at the University of Wisconsin. The writer wishes to take this opportunity to extend his thanks to Professor B. M. Ducear, at whose suggestion and under whose direction the work was begun, and also to Professor R. A. HARPER and Professor W. G. MARQUETTE for valuable assistance and helpful — UNIVERSITY oF WISCONSIN MapIson, Wis. THE MALE GAMETOPHYTE OF ABIES A. H. HutcHinson (WITH FIFTEEN FIGURES) In a study of Abies balsamea as a type of the Coniferae, a num- ber of irregularities in the contents of the pollen grain have been observed. Since the material used was collected from different trees and in different years, these irregularities cannot be regarded as abnormalities; and since further examination showed that similar conditions prevail in at least two other species of Abies, these observations have been thought worthy of record. For the material I am indebted to Professor R. WILSON SMITH. A. balsamea was collected in Ontario; A. Veitchii and A. brachy- phylia were obtained through the courtesy of the authorities of the Royal Gardens at Kew. The pollen grain of Abies balsamea is very large, its diameter being about twice that of Pinus. At the time of shedding the normal grain contains two prothallial cells, a stalk cell, a body cell, and a tube nucleus, imbedded in a vacuolated protoplasmic mass which contains numerous starch grains (fig. 1). ‘The nucleus of the body cell is surrounded by dense protoplasm and a ce membrane. The tube nucleus is large and usually compressed; some instances the pressure, resulting from the extraordinary growth of the cells of the gametophyte, is insufficient to force it from its polar position to a lateral one. The stalk cell is much smaller than the body cell, and quite frequently is compressed into a cavity at the prothallial end of the latter. In A. Veitchit and A. brachyphylla the prothallial cells are very much flattened at this stage; but in A. balsamea it is not uncommon to find both prothallial cells retaining the characteristic nuclear structure. The size and permanence, however, varies with the individual as well as with the species. The material examined does not show stages earlier than the division of the central cell into generative cell and tube nucleus. Peculiarities in this division are described later. The periclinal Botanical Gazette, vol. 57] [148 1914] HUTCHINSON—MALE GAMETOPHYTE OF ABIES 149 division into stalk and body cells takes place six or seven days before pollination. At this time the prothallial cells are at their maximum size. . F man n 3 < Fics. 1-3.—A bies balsamea: fig. 1, ripe pollen grain; figs. 2, 3, at time of shedding, Owing divisions of prothallial cells; p, prothallial cells; 6, body cell; s, stalk cell; ¢, tube nucleus; all x610. Frequent variations in the number of prothallial cells occur. € maximum number is four (figs. 2 and 4), but three are of more frequent occurrence (figs. 3 and 5). The division, as indicated by the position of the daughter cells, is anticlinal, either in or at right angles to the plane of the wings, hence they are best seen in a polar view. The presence of two derivatives of a prothallial cell, wher 150 BOTANICAL GAZETTE [FEBRUARY they lie one over the other, is easily overlooked. It is difficult, therefore, to determine the proportion of pollen grains in which there are more than two. In A. balsamea about 8 per cent show a division of one or both of the original prothallial cells; in A. Vettchit and A. brachyphylla the number is smaller. In some cases Fics. 4-7.—Figs. 4, 5, A. balsamea at time of shedding, showing divisions of prothallial cells and division of body nucleus int le nuclei (m); fig. 5 shows nuclear division in stalk cell; figs. 6, 7, A. Veitchii, showing two male nuclei, two derivatives of stalk cell, and prothallial cells much flattened; lettering as in the last; all X610. the separating wall, if formed, becomes obliterated and the appeat- ance is that of nuclear division only (fig. 2). In approximately 1o per cent of the gametophytes the nucleus of the body cell divides before pollination into male nuclei. These are large and well developed, and imbedded in a common mass of protoplasm which is inclosed by the wall of the former body cell. 1914] HUTCHINSON—MALE GAMETOPHYTE OF ABIES 151 Miyake describes two male nuclei which enter the archegonium, and the one which fuses with the egg nucleus is said to be the larger. Before pollination, no difference in the size of structure could be detected (figs. 4 and 7), and MryAxe’s drawings show little or no difference in the pollen tube stage. Occasionally the stalk cell also divides to form two derivative cells. The division is sometimes anticlinal (fig. 7), and sometimes periclinal (figs. 5 and 6). When this -division takes place, the resulting nuclei fre- quently become uniformly granular and gradually degenerate. In this case also the separating walls are not always present (fig. 5) and the appear- ance is suggestive of amitosis. There may be as many as four derivatives of the generative cell. In order to ascertain how many of the nuclei enter the egg at fertilization, an examination of the archegonium wasmade. Frequently there are four supernumerary nuclei at the micro- pylar end of archegonium after fertili- zation and during the proembryo Stage (fig.8). These in all probability are the second male nucleus, the two derivatives of the stalk cell, and the tube nucleus. Mrvaxe states that these nuclei have the power of divi- four nuclei of proembryo; 6:0. Sion. An examination of pollen grains lodged in the micropyle shows that while the other contents have passed into the pollen tube, the prothallial cells do not escape, but are retained by the intine in which they are imbedded. _ The division of the generative cell in Abies may be an adapta- Hon to the rapid succession of events between pollination and ferti- lization: about 4 weeks in A. balsamea and 1 3 weeks in Pinus. Picea 152 BOTANICAL GAZETTE [FEBRUARY excelsa (POLLOCK) is similar in this respect. The division of the stalk cell cannot be so regarded; it may represent ancestral condi- tions. If so, it indicates a survival in Abies of a more ancient type of gametophyte than has been reported in any other of the Abietineae. Further, as the presence or absence of prothallial cells is a rather constant character of the different groups of Conif- erae, and thus may have a phylogenetic significance, the presence of several prothallial cells may suggest a connection of the abietin- Fics.'9-15.—A. balsamea ten days ae shedding: figs. 9-13, ees) stages in telophase of mitosis of central cell; the relative positions are indicated by that t of the prothallial cell; fig. 14, polar view of stage shown in fig. 13; fig. 15, asi of generative cell below ee line during stage shown in fig. 13, or just after formation of cell membrane; all X92 ean and araucarian lines; which connection is also indicated by evidence accumulating from other sources. Certain peculiarities in the division of the central cell to form the generative cell and tube nucleus have been mentioned. Atten- tion was drawn to these by the very conspicuous radiating strands which surround the generative nucleus, as seen in a polar vieW (fig. 14). Further investigation shows these to be derived from the spindle, and that they take part in the formation of the ¢ membrane. ell 1914] HUTCHINSON—MALE GAMETOPHYTE OF ABIES 153 In the late telophase no well defined cell plate is formed, although thickenings of the fibers may occur (fig. 9). The central fibers of the spindle disappear, either ceasing to be differentiated by the stain, or, as is more probable, they move out and become peripheral (fig. 10). Gradually the spindle widens and moves away from the tube nucleus, thereby inclosing the generative cell in the form of a hollow globe (figs. 10 and 11). The fibers continue to move upward until they come in contact with the wall of the second prothallial cell (figs. r2 and 13). Meanwhile the cell mem- brane is formed in the position occupied by the peripheral fibers. When the wall is complete the fibers have disappeared. Although derived from the spindle, the cell wall does not originate from a cell plate, but from the fibers after they have surrounded the generative nucleus. Whether or not the fibers fuse laterally is difficult to determine; that they are very numerous and form a dense, almost continuous, envelope about the generative nucleus is shown in a polar view (fig. 14). The definite cell membrane which is formed is best shown in cross-section. Fig. 15 represents such a section of a cell at the stage shown in fig. 13. These peculiarities may perhaps be accounted for by the fact that the division is internal, and only one of the resulting nuclei is inclosed by a wall; hence this method of delimiting the cellular Protoplasm. One is reminded of the formation of the plasma membrane about the ascospore of Phyllactinia as described by ER, McMaster UNIVERSITY Toronto, CANapa CURRENT LITERATURE BOOK REVIEWS Parasitic fungi A book treating of the fungi which cause plant diseases, which limits itself to the diseases already known in the United States and to those which, known elsewhere, seem likely to invade this country, ought to be received gratefully by the American student of plant pathology. In his new book, STEVENS' gives keys and descriptions of the fungi which cause plant diseases and also of such saprophytic forms as are obviously closely related to the parasitic forms. But he does more than give a taxonomic account of the parasitic forms, since he presents the results of cytological work, usually with the original figures, in all those groups in which extensive cytological studies have appeared: As would be expected, he also goes into details of culture methods in such groups as the rusts, where an elaborate method of procedure has been evolved by specialists. relation to other thallophytes, the book comprises three divisions. The first division treats of Myxomycetes, the second of Schizomycetes. There follows on Ascomycetes with 344 references, one on Basidiomycetes with 345 references, ences. In addition, there are 64 books and 12 periodicals which are listed as “some of the most useful.” In connection with so extensive a bibliography it is to be lamented that citations are not made in full so as to include the titles of papers. Such a list as STEVENS publishes, in which appears an author's name, a volume reference (abbreviated as much as possible), a first page, and a date, might be quite satisfactory had we reached the day of perfect proof- reading, when each word and figure would stand as it should, and it would not be necessary to turn back to the index of the volume indicated to see whether it was merely the page reference that was wrong or whether the volume number was at fault. Nor can we say that up to this moment we have found the proofreading of these bibliographies imperfect, but a number of very obvious. slips in the text would indicate that this might be possible. Thus, on page 7?, Cladochytrium, after being listed in the key under intracellular forms, 8 described as a genus containing about ten intercellular parasites; and on page * STEVENS, F. L., The fungi which cause plant diseases. 8vo. pp. Vilit754- Jigs. 449. New York: The Macmillan Co. 1913. $4.00. 154 1914] CURRENT LITERATURE 155 75, it is said of Dictyuchus: “This genus of the Saprolegniaceae contains the only parasite genus in the first two families.” Turning then to the end of the book, we find sprodochium for sporodochium on page 664, “‘synnema or corymium” for coremium on page 565, while synema appears on page 694 of the glossary, and on page 443 Merasmieae appears instead of Marasmieae. In several points StEvENS helps to overcome inconsistencies which are common in works on parasitic fungi. Striking among these is his listing of the three groups of Fungi Imperfecti (the group which is characterized chiefly by the imperfection of our knowledge of them) in the three orders Sphaeropsidales, Melanconiales, and Moniliales, rather than Sphaeropsidales, Melanconiales, and Hyphomycetes. In this connection it is unfortunate that he should speak of the types of fructification displayed by Fungi Imperfecti as pycnidia, acervuli, and hyphae, in spite of the fact that the definition of hypha in the glossary is “the thread-like vegetative part of a fungus.” Altogether this book, with its concise, clear keys of parasitic fungi, which aims to give at least one illustration as well as description of each genus of €conomic importance in the United States, and which has a comprehensive bibliography, must prove a stimulus to the student of plant pathology.— Wanpa M. Prerrrer, rt NOTES FOR STUDENTS Current taxonomic literature-—H. ANDRES (Verhandl. Bot. Ver. Prov. Brandbg. 54:218-227. 1913) has published two species of Pyrola, one being from the state of Washington, and (Oesterreich. Bot. Zeitschr. 63:68-75. 1913) three species are added from the Pacific Coast. The same author (Allg. Bot. Zeitschr. 19:81-86, 1913) in a closing article on the Pyrolaceae includes the description of a new species (P. cordata) from Ontario, Canada.—H. H. Bartterr (Rhodora 1581-8 5- 1913) in continuation of systematic studies on Oenothera has published jointly with G. F. ArKrnson two new species of this genus from New York.—O. Beccarr (Webbia 4:143-240. 1913) under the title Contributi alla conoscenza delle Palme” has published the results of further Studies of the palms, describes a new genus (Jubaeopsis) from Central Africa, and gives a revision of the genus Pritchardia which includes several new species from the Hawaiian Islands.—G. Brrrer (Rep. Sp. Nov. 12:49-90, 136-162. bis. 1, 2. 1913) has published upward of 50 new species and several varieties of Solanum mostly from America.—S. F. BLake (Rhodora 15:86-88. 1913) - Ss two new forms of Ophioglossum vulgatum from eastern North America, and (ibid. 153-168) under the title of “Six weeks’ botanizing in Vermont. I. Notes on the plants of the Burlington region” presents the results of a study of © Plants collected in the Champlain Valley of Vermont in rort, adding Several species not hitherto recorded from the Burlington region and describes @ number of new varieties and forms.—C. BoOrner (Abh. Nat. Ver. Bremen *1*245-282. 1913) under the title “Botanisch-systematische Notizen” has 156 BOTANICAL GAZETTE [FEBRUARY proposed several new generic namés for somewhat aberrant or habitally distinct forms of well known genera. The names are numerous and attention is called merely to their place of publication.—E. Brarnerp (Bull. Torr. Bot. Club 40:249-260. pls. 15-17. 1913) describes four new hybrid violets; and (Rhodora 15:106-111. pl. 104. 1913) in continuation of his studies on the violets presents a discussion on the Old World Viola arenaria DC. in relation to its American ally and characterizes a new variety, namely, V. adunca var. glabra. The same author (ibid. 112-115) under ‘‘Notes on new or rare violets of Northwestern America” describes a new variety of V. cucullata Ait. and adds several new hybrid combinations—A. Branp (Ann. Conserv. and Jard. Bot. Genéve 15 and 16:322-342. 1913) in continuation of studies on the Polemoniaceae records further information on this family and describes several new species and varieties from western United States, and (ibid. 343-344) publishes two new species of Symplocos from America.—T. S. BRANDEGEE (Univ. Calif. Pub. Botany 4:375-388. es 3 oe published 35 new species, based on collections made in Mexico by . A. Purpus in 1912.—N. L. Britton pe: ¥32215-217. 1913) a 4 new species of Cyperaceae from the Wes desestind ee living specimens 7 new species from Mexico and Central America. The same authors (ibid. 255-262. pls. 78-84) under the title “The genus Epiphyllum and its allies” present a systematic treatment of Epiphyllum, to which Phyllocactus Link is referred as a synonym, and the immediately allied genera, as follows: Epiphyllum (28), Disocactus (2), Zygocactus (3), Schlum- bergera (2), Wittia (3), and Epiphyllanthus (1); Eccremocactus and d Stropho- cactus, each represented by a single species, are proposed as new generic types- —L. Buscattonr and G. MuscatTetto (Malpighia 25:187-250. 1912) under the title “Studio monografico sulle specie americane del gen. Saurauia Willd.” give a synoptical revision of the genus and include descriptions of two new species from South America, and (ibid. 389-436. pls. 7, 8) in continuation of these studies add two more species of Saurauia from Mexico.—F. Ciements, C. O. Rosenpant, and F. K. Burrers (Geol. and Nat. Hist. Surv. Minn., Minn. Bot. Studies. pp. ix+s5o. as have issued the third edition of the “Guide to the spring flowers of Minnesota, field and garden.” —O. F. Coox (Contr. U.S. Nat. Herb. 16: 243-254. pls. 74-77. 1913) presents a discussion of the false date palm (Pseudophoenix Sargentii Wendl.) and creates for it an independent family, namely Pseudophoenicaceae. Inan accompany1ng key to the families of American palms the new family is placed between the Ceroxylaceae and the Cocaceae—L. Damazto (Broteria Ser. Bot. 11:51~53- ods 3) describes and illustrates a new species of Cassia (C. itaculumiensis) from —H. Drepicxe (Ann. Mycol. 11:172-184. 1913) under the title “Die Engen aeeee describes two new genera, namely, Pycnothyrium found on leaves of Mercurialis perennis and Thyriostroma on Pteris aquilina.— A, Di Ermer (Leafl. Phil. Bot. 5:1589-1750. 1913) in cooperation with several 1914] CURRENT LITERATURE 157 specialists has issued articles 78-92 inclusive of the Leaflets. About 120 new species and varieties of Philippine plants are described.—F. FEppE (Rep. Sp. Nov. 12:278-279. 1913) records a new species and variety of Corydalis from K. M. Wiecanp (ibid. 133, 134) characterize two new varieties of Carex from Newfoundland and (ibid. 135, 136) a new form of Calamagrostis Pickeringii ‘Gray.—C. N. Forses (Occ. Papers Bern. Pau. Bishop Mus. Eth. and Nat. Hist. 5:3-26. 1913) places on record notes concerning the flora of the Hawaiian Islands and describes a new species of Euphorbia (E. Stokesii).—E. GADECEAU and O. Srapr (Rev. Hort. Paris 85:422-426. 1913) describe and illustrate a new species of Mandevillea (M. Tweedieana) indigenous to South America.— . GaIn (Deuxiéme Expédition Antarctique Francaise, 1908-1910, commandée par le J. Cuarcor, pp. 218. pls. 1-8. 1912) records the results of a study of the algae secured on the expedition and describes several species new to science. —H. A. Greason (Bull. Torr. Bot. Club 40: 305-332. 1913) in continuation of studies on the Vernonieae has published several new species and gives a synopsis of the group as represented in the West Indies.—A. GRIFFINI (Atti Soc. Ital. Sc. Nat. Milano 52:61-104. 1913) under the title ‘Sopra alcuni Grillacridi e Stenopelmatidi della collezioni Pantel’”’ includes the description of a new genus (Paterdecolyus) from India. The new genus is related to Anabropsis.—D. RIFFITH (Monatsschrift fiir Kakteenkunde 23:130-140. 1913) describes several new species of Opuntia and a new Nopalea from Southwestern United States and Mexico.—H. Gross (Bull. Geogr. Bot. 23:7-32. 1913) under the title “Remarques sur les Polygonées de l’Asie orientale” presents a synopsis of the genera of this family, as represented in eastern China, describes several new species and one new genus (Pleuropteropyrum).—H. E. Hasse (Contr. U.S. Nat. Herb. 17:1-132. 1913) has published a “Lichen flora of Southern California.” The region covered by the author is that portion of California south of the 36°. parallel or about one-third of the state. Five families of lichens are recognized embracing 60 genera and approximately 360 species.—E. Hasster (Rep. Sp. Nov. 12:201, 202, 249-278. 1913) describes about 75 new Species, belonging mostly to the Apocynaceae, Malvaceae, and Onagraceae, from Argentina and Paraguay. One new genus is characterized, namely, Casimirella of the Icacinaceae —A. HEIMERL (Oesterr. Bot. Zeitschr. 63:279- 799. 1913) under the title “Die Nyctaginaceen-Gattungen Calpidia und Rockia” revives Calpidia Thour. and proposes a new genus (Rockia) based on illeb . HELLER (Muhlenbergia 9:60-65. 1913) in an article entitled “Acmispon in Cali ornia” recognizes 6 species of this genus, 4 of which are described as new to science. The same author (ibid. 67, 68) makes 23 new combinations in the iminosae, Onagraceae, and Ericaceae.—G. Hiyze (Ber. Deutsch. Bot. Gesells. 31: 189-202, pl. 9. 1913) under the title “Beitrage zur Kenntnis der 158 BOTANICAL GAZETTE [FEBRUARY farblosen Schwefelbakterien” proposes a new genus (Thiovulum) from the Gulf of Naples.—A. Korscuikorr (ibid. 174-183. pl. 8. 1913) describes and illustrates a new genus (Spermatozopsis) of the Volvocales—B. Koso- PorjaNsky (Jour. Russe de Bot. no. 1-2. pp. 1-10. pls. 1-5. 1913) under the title “Species Umbelliferarum minus ceauak “has ublished several new species of Umbelliferae and includes a new genus (Glochidopleurum) based on Bupleurum Sintenisii Aschers. and Graeb—F. KrAnzi1n (Ann. K.K. Natur- hist. Hofmus. Wien 27:109-112. 1913) has published 5 new species of Spiran- thes from South America.—K. Krause (Smith. Misc. Coll. 61: no. 16. p. I. 1913) describes a new species of Esenbeckia (E. Pittieri) from Colombia.—G. UKENTHAL (Rep. Sp. Nov. 12:91-95. 1913) under the title “Cyperaceae novae III’’ has published several new species and varieties including 4 from South America.—C. LAUTERBACH (Bot. Jahrb. 50:1-170. 1913) in cooperation with certain specialists has issued the second article under the general title “Beitrige zur Flora von Papuasien.’’ Several species new to science are recorded and the following new genera are proposed: Mischocodon Radlk. of the Sapindaceae, Astelma Schltr. of the Asclepiadaceae, Ancylacanthus and Jadunia Lindau of the Acanthaceae.—R. LAUTERBORN (Allg. Bot. Zeitschr. — 1913) under the title “Zur Kenntnis einiger sapropelischer Schi lea, Pale, and Peloploca—H. LEVEILLE (Rep. Sp. Nov. 12:99-103- 1913) several new species of flowering plants from Asia and includes a new genus (Bodinisriella) of the Ericaceae.—G. Lrnpau (Ber. Deutsch. Bot. Gesells. 31: 243-248. pl. rr. 1913) publishes an account of a new fungus to which he gives the name Medusomyces Gisevii. The new genus is related to Mycoderma.—T. LorsENER (Rep. Sp. Nov. 12:217-244. 1913) in cooperation with several specialists under the heading ‘‘Mexikanische und zentralameri- kanische Novitaten IV” has published several new species of flowering plants. —Fr. Marre-Vicrorin (Le Naturaliste Canadien 39:177-180. 1913) under “Notes sur deux cas d’hybridisme naturel” treats Mymphaca rubrodisca RAs Greene as a hybrid between NV. americana (Prov.) Miller and Standley N. microphylla Pers., and records a new hybrid between Lysimachia oe (L.) B.S.P. and L. thyrsiflora L—A. MAvuBtan (Bol. Minist. Agr. Ind. and Com. Rio de Janeiro 2:126—130. 1913) in a paper entitled ‘““Uma molestia do mamoeiro” describes and illustrates a new fungus (Sphaerella Caricae) found on leaves of the pawpaw (Carica Papaya L.) and proposes a new generic name ( Asperisporium) based on F eu ga Peucedani Ell. & Holw.—W. R. Maxon (Smiths. Misc. Coll. 61: no. 4. 1-5. pls. 1, 2. 1913) describes and illustrates a new genus of ferns (Saffordia) from Peru. The same author (Contr. U.S. Nat. Herb. 17:133-179. pls. 1-10. 1913) under the title “Studies of tropical American ferns no. 4” has published a paper embodying results of a continued study of ferns and fern-allies, recording import rtant data and describing new species in Asplenium, Dicksonia, Odontosori Bommeria, Hemionitis, Lycopodium, and Cyathea——N. NAouMOFF Bull. ‘Soc. Mycol. a 1914] CURRENT LITERATURE 159 France 29:273-278. pl. 13. 1913) under the heading “Matériaux pour la flore mycologique de la Russie’ includes the description of a new genus (Rhodoseptoria) found on leaves and fruit of Prunus.—B. NKMEc (Rozpravy Ceské Akademie 21:1-16. pls. 1,2. 1912) describes and, illustrates a new genus and species (Anisomyxa Plantaginis) parasitic on Plantago lanceolata.—J. A. NIEUWLAND (Am. Mid. Nat. 3:85-o1. #l. 2. 1913) has published a new species of violet ( Viola candidula) from Michigan.—S. B. ParisH (Bot. Gaz. §5:300- 313. 1913) under the title of “California Paroselas” recognizes 9 species and several varieties of this genus indigenous to California. The same author (Muhlenbergia 9:57~s9. 913) in an article entitled “Additions to the known flora of southern California” places on record important data concerning that flora and describes a new species of Atriplex (A. saltonensis) from the Colorado Desert—F. W. PENNELL (Bull. Torr. Bot. Club 40:401-439. 1913) gives a synoptical revision of the Agalinanae, recognizing four genera, namely Macran- thera, Afzelia, Aureolaria, and Agalinis. Descriptions of several new species are included—C. A. Prcquenarp (Trav. du Lab. de Concarneau 4: fasc. 3. PP. 1-5. pl. 1. 1912) has proposed a new genus (Guerinea) based on Hapali- dium callithamnoides Crouan.—R. PILGER (Bot. Jahrb. 50:171-287. 1913) in continuation of monographic studies of the Plantaginaceae gives a detailed consideration of the section Novorobis of Plantago, recognizing 50 species of which nearly one-third are new to science. The same author (Rep. Sp. Nov. Asplenium—R. A. RourE (Bot. Mag. ¢. 8514. 1913) describes and illustrates: 4 new orchid (Catasetum microglossum) from Peru.—J. N. Rose (Smiths. Misc. Coll. 6r: no. 12. Pp. 1, 2. pl. r. 1913) describes and illustrates a new poplar (Populus MacDougalii) from the Salton Basin, California.—P. A. RYDBERG. (Bull. Torr. Bot. Club 40: 461-48 5. 1913) under the title “Studies on the Rocky Mountain flora XXIX” describes several new species of Sympetalae.— m SCHLECHTER (Rep. Sp. Nov. 12: 104-109, 202-206, 212-216. 1913) in con- tnuation of his work on orchids has published upward of 20 new species from tropical America. One new genus (Ischnogyne) from the mountains of N Fatt (Correya 13:77. 1913) describes a new species of Malpighia (M. orrisit) from Jamaica.—J. D. Surra (Bot. Gaz. 55:431-438. 1913) presents *» 160 BOTANICAL GAZETTE [FEBRUARY his 36th paper, as a result of continued study on the flora of Central America. The article includes descriptions of 12 species of flowering plants new to science. —J. D. Smitu and J. N. Rose (Contr. U.S. Nat. Herb. 16:287—298. 1913) have published a ‘Monograph of the Hauyeae and Gongylocarpeae, tribes of Onagraceae.”’ The study embraces 4 genera and 14 species; two new generic names are proposed, namely, Xylonagra, based on Oenothera arborea Kellogg, and Burragea, based on Gaura fruticulosa Benth.—W. W. Smits (Rec. Bot. Surv. India 4:324-431. 1913) records the results of a botanical survey of South- east Sikkim, India, lists 925 species, and describes a new genus (Paroxygraphis) of the Ranunculaceae.—C. Sprcazzini (Ann. Mus. Nac. Buenos Aires 23:167- 244. 1912) in an article on the Laboulbeniaceae of Argentina has published several new species and proposes two new genera, namely, Cochliomyces and Laboulbeniella. The same author (ibid. 1-146) under the title ‘“Mycetes Argentinenses” continues the enumeration of the Mycetes of Argentina, adds several species new to mags and proposes the following new genera: Eudimeriolum, Winteromyces, Ti selene riy om Dasysphaeria, Criserosphaeria, Hormopeltis, Polhysterium, ‘sym phaeophyma, A gap eB a mH ae Das- ysticta, Dasyprena, Phaeopolynema,and Phaeolabrella.—A. RD (Proc. Cali Acad. Sci. 1:431-446. 1912) oo the lichens found on ro pe of the California Academy of Sciences to the Galapagos Islands in 1905-1906. Six- teen species were found which were not before reported from the islands.—H. and P. Sypow (Ann. Mycol. 11:93-118. 1913) have published several new species of fungi from northern Japan and characterize a new genus (Miyagia) of the Pucciniaceae found on leaves of Amnaphalis margaritacea. The same authors (ibid. 254-271) under the title “Novae fungorum species X” have published several species new to science and propose the following new genera: Aithaloderma, Schizochora, Cyclodothis, and Diedickea from the Philippine Islands, Astrosphaeriella and Coccidophthora from Japan, and Nematostigma from South Africa.—C. Torrenp (Broteria, Ser. Bot. 11:73-98. 1913) under Fiel (Beira Baixa)” includes the descriptions of several new species and proposes one new genus, namely, Lycoperdellon, based on Lycogala Torrendii Br I. Urzan (Bot. Jahrb. 50: Beibl. 111. pp. 1-108. 1913) under the title “Plantae novae andinae imprimis Weberbauerianae VI” in cooperation with severa specialists has published an important paper on the Andean flora. About 125 species new to science are described.—H. F. WernHAM (Jour. Bot. 51: :218- 221. 1913) has published rz new species of Rubiaceae from tropical America. —R. S. Wit1aMs (Bryologist 16:36-39. pl. 4. 1913) reports Brachymenium macrocarpum Card. from Florida and — a new species of Funaria (F. rubiginosa) from Montana.—J. M. G Metabolism of fungi.— Believing that methods based on a determination of the yield, or of the economic or the respiratory coefficients do not give 4 factory quantitative representation of the manner of utilization of carbon * 1914] CURRENT LITERATURE 161 compounds by fungi, WATERMAN? has applied the conceptions of “‘plastic equiva- bon dioxide. Experimentally these relations are obtained by determinations of the carbon given off in respiration, the quantity fixed in the body of the fungus, and the total quantity that has been consumed. The author has studied from this point of view the assimilation of glucose, levulose, mannose, and a number of organic acids. As a rule, however, only the plastic equivalents were determined, the respiratory equivalent having been determined only for succinic acid. The results show, apparently to the mild Surprise of the author, that the plastic equivalent is high during the early Stages of growth, and falls with increasing age of the culture; while the greater Part of the carbon nutrient disappears during the first few days of growth. From these observations he arrives at his main conclusion, that the temporary accumulation of carbon in the fungus is due to the formation of an intermediate product which he finds to be glycogen. This view, of course, presents nothing novel, for it is well known that in the presence of an excess of food, reserve materials, which in fungi mostly take the form of glycogen, are stored in the plant body, and that respiratory activity, decreasing the “plastic equivalent,” continues at the expense of reserve materials and even at the expense of pro- teids when the external food supply has been exhausted. All such substances must in this sense be regarded as intermediate products. In this connection it may be pointed out that from the discrepancy between the quantity of carbon dioxide developed by a fermenting mixture and that which should have been developed according to the quantity of glucose (determined by change in rotation) which disappeared from the mixture, EULER and JouaNsson® have recently concluded that intermediate products were first formed from the glu- Cose in the process of fermentation. Regarding the author’s method it should also be stated that SPIEKERMANN,! without giving special names to the ratios, determined for a species of Penicillium growing on glycerin the percentage of the consumed carbon fixed in the plant body, and that given off in respiration. Finally, WaTERMANN has investigated the influence of various factors in relation to the plastic equivalent. Changes in temperature and in concentra- Hon of the nutrient medium do not influence the nature but only the rate of tty _ ‘WATERMAN, H. I., Beitrag zur Kenntnis der Kohlenstoffnahrung von Aspergillus miger. Folia Microbiol. 1:422-485. 1913. > Euter, H., und Jonansson, D., Umwandlung des Zuckers und Bildung der Kohlensiure bei der alkolischen Garung. Zeitschr. Physiol. Chem. 76: 347-354. 1912. ' a. , A., Die Zersetzung der Fette durch hdhere Pilze. Zeitschr. ee, oe - Nahrungs- u. Genussmittel 23: 305-331. 1912. 162 BOTANICAL GAZETTE [FEBRUARY metabolism. The magnitude of the plastic equivalent is to a high degree dependent on the nature of the carbon nutrient. This relation is correlated with the heats of combustion of the carbon compounds. Those having the greater caloric value give the highest plastic ratios —H. HASSELBRING. Bud variations and fruit markings.—This very interesting question is the subject of a paper by Kraus, who has been making studies on the effects of cross-pollination of cultivated fruits. The author calls attention to the fre- quent occurrence of banded or striped fruits, especially among apples. The most common explanation of this phenomenon is the secondary influence of pollen, but the author explains that this cannot be true xenia, such as occurs in corn. Correspondence with horticulturists and botanists indicated a prevail- ing opinion that it is due to secondary influence of pollen, though a number believed it due to bud-variation. After explaining the economic importance of the problem, the author describes his methods of work. The conclusions are as follows: ‘color in the pome fruits is not influenced directly in the immediate cross; new characters cannot be added by the pollen, outside the seed itself, in the immediate cross; the manifestation of color is dependent on many environmental factors; color as usually found is composed of a number of unit characters; somatic segregation may occur and by this means the several factors of color manifest themselves more or less independently (the several colors may appear as bands more or less parallel, or a band of but one color surrounded by the normal color); similar segregation may extend to any group of unit characters of which the plant is composed; segregation may extend to either fruit or leaf buds; if the latter, such variations may be propagated asexually; red in apples may consist of either a single or a complex of unit characters; at least, three reds are recognizable; somatic segregation may be of service to plant breeders as indicating the unit characters of a plant that are likely to exhibit themselves when propagated sexually; segregation generally extends to the flower bud only in apples, while in pears the shoot is frequently affected.” —Met T. Cook. The development of chalazogams.—NAwASscHIN and Finn‘ have pub- lished a contribution in German which extends the study of Juglans published in Russian a year ago and already noted in this journal.7 The principal conclusions’are: that in seed plants there is a tendency to reduce the male gametes from sperms to naked nuclei; that the evolution of the pollen tube and simplification of the sperm go hand in hand; that Juglans and other chalazoga- mous plants with a well developed binucleate cell which reaches the embry? 5 Kraus, E. J., Bud variations in relation to fruit markings. Biennial Crop Pest and Horticultural Report for r911 and 1912. Oregon Agric. Exp. Station. pPp- 73-78- 6 Nawascauy, S., and Fryv, V., Zur Entwickelungsgeschichte der Chalazogamen- Juglans regia und Juglans nigra. Mém. Acad. Imp. Sci. St. Pétersbourg 311-59 pls. I-4. 1913. 7 Bot. Gaz. 55:94. 1913. 1914] CURRENT LITERATURE 163 sac in fact show a condition intermediate between a well developed sperm and a naked sperm nucleus; and that this feature indicates the great age of chalazo- gams. These conclusions, which are practically the same as those given in the previous paper, are based upon a large amount of research and also upon a thorough discussion of the literature, in which the work of American investiga- tors receives generous recognition. Both authors had already become identi- ed with the subject, and no one has contributed more to our knowledge of chalazogamous plants than NAWASCHIN. Besides, as the discoverer of “double fertilization,” he has made a reputation for brilliant initiative in research, while his more recent investigation of the sperm nucleus of Lilium Martagon entitles him to a place among the authorities in cytological matters. These facts lend weight to the conclusions. The paper deserves a carreul reading by everyone who attempts to treat th a cytological standpoint. Three of the large plates are e colored, and ‘the fourth (copied from various investigators) gives a useful optical survey of pollen tube structures in Various groups of gymnosperms and angiosperms.—CHARLES J. CHAMBERLAIN. ) Sedum are discussed. Hovarv? gives good descriptions of a number of cecidia in the Natural History Museum of Paris, restricting his discussions to the galls and not to the causes. KIEFFER™ Sadiatbes two new genera and two new species of cecidomyid galls and gall-makers from Formosa. ong the most interesting American contributions is a very suggestiv Paper on seedless and malformed fruits by BRowN," in which the author, fey sing malformations and Sasi. caused by frost, also calls attention to the fact that fruits may b las a result of no pollination or imperfect Pollination combined with frost i injuries. After pollination, a severe frost may interfere with the fertilization processes and affect both seed.and fruit. The author also states that there is relationship between weights of seeds and fruit but does not give figures. FELT? contributes a very valuable entomological study of gall midges, in spel — a, descriptions, and drawings of a great many species. T. Coo: * Buysson, H. pv, et pipe Sipe Nouvelles cecidologiques du centre de la France. Marcellia 12: 27-35. 19 *Hovarp, C., Les fea cécidologiques du Jaboratoire d’entomolgie du. Museum histoire naturelle du Paris: Galles du Mavor. Marcellia 12:35-41. 1913. ” Krerrer, J. J., pee de deux remarquables cécidomyies de Formose. Marcellia 12:42-44. 1913 ~Dkows, F. R., Seadiias and malformed fruits. Biennial Crop Pests and 5 eta Report lox Igtt and 1912. Oregon Agric. Exp. Station. ,» A study of gall midges. Lise ta Report of the Ento- a Shay of the State of Lah York. pp. 127-226. 1913 164 BOTANICAL GAZETTE [FEBRUARY Parthenogenesis in Bennettites.—Parthenogenesis, or the development of an embryo from an egg without fertilization, has been demonstrated for several angiosperms, and is claimed for Pinus pinaster and Gnetum Ule. In spite of the difficulty of proving a case of parthenogenesis in living seed plants, LIGNIER* has given us a short paper with the rather startling title ‘‘ Bennettites Morieri probably reproduces by parthenogenesis.”’ One naturally looks for the evidence. Here it is. He found embryos, but no pollen grains or pollen tubes, and the tip of the nucellus was closed. Some of the sections were in series, at intervals of about 3mm. Presumably most of the sections were not in series. hen one remembers that pollen tubes have never been demonstrated in the Bennettitales and that very possibly the pollen grains may shed their sperms without the formation of a pollen tube, and that even in rather thick sections at intervals of 3 mm., more than nine-tenths of the material is missing, the evi- dence is not convincing. And yet, this “probable parthenogenesis” is given as a reason for the rapid disappearance of this group during the Cretaceous.— CHARLES J. CHAMBERLAIN. A classification of conifers ——Saxton™ has proposed a classification of conifers based upon the great extension of knowledge of the group developed during recent years. There is no question that the current classifications are archaic, and that a more natural classification of the group is demanded. SAX- TON analyzes the characters to be used in such a classification, and discusses the various attempts that have been made. He then describes, with definite i , Podocary , Pinaceae, Cupressaceae, and Taxaceae), Pinaceae having two subfamilies (Abietoideae and Sciadopitoi- deae) and Cupressaceae three (Cupressoideae, Callitroideae, and Sequoideae). A consideration of the phylogeny of Coniferales results in an interesting “family tree” that shows the relationships of the families and subfamilies. An interesting item of the phylogeny, at this time, is that the araucarians are represented as the first offshoot from the common stock (presumably abietin- ean) that arises from Cordaitales, which later gave rise to the podocarps, and then the other families.—J. M. C. characters. five families (A Ps \ Artificial parthenogenesis in Fucus.—Parthenogenesis in various members of the Phaeophyceae has been known for some time, and unfertilized eggs of Fucus have been caused to divide by treating them with solutions. OvERTON’S took exceptional care to obtain unfertilized eggs of Fucus vesiculosus, and each collection was divided into three lots, one of which was then fertilized, another was allowed to remain in normal sea water, while the third was treated wl 3 LIGNIER O., Le Bennettites Morieri (Sap. et Mar.) Lignier se reprodusait probablement par parthénogénése. Bull. Soc. Bot. France IV. r1:125-127- 191! ™ Saxton, W. T., The classification of conifers. New Phytol. 12:242-262. 1913- 's QvERTON, J. B., Artificial parthenogenesis in Fucus. Science 37:841, 844- 1913: 1914] CURRENT LITERATURE 165 acetic or butyric acid. The general result of the various cultures was that in the first case the sporelings developed normally; in the second, no sporelings appeared; while in the third, sporelings developed up to the 25-cell stage. The experiments were not carried farther. No cytological work was done. Since the Fucus plant is the 2x generation, it would be interesting to know the chromosome situation, especially if the plants should develop up to the repro- ductive phase.—Cnar.Es J. CHAMBERLAIN. Chromosome conjugation.— Miss FRASER," in a short discussion of chromo- some conjugation, cites the work of OVERTON, HarPER, Dicsy, and others to show that it is not a matter of primary importance whether parasynapsis or telosynapsis takes place, and that they need not be mutually exclusive. e sexual nuclei may fuse at once upon fertilization, or not until the division of the oospore in other cases (Pinaceae); while in the extreme case of the rusts they remain distinct until just before meiosis. In like manner the attraction between the homologous chromosomes may bring about their conjugation as soon as the nuclei fuse, or in other cases later, even as late as the formation of the gemini of maturation. The suggestion is made that the clearest cases of Mendelian inheritance will perhaps be found to be those correlated with a late association of the chromosomes in pairs.—L. W. SHARP. + Flora of Boulder.—Dante1s” has made a study of the vascular flora of Boulder, Colo., and vicinity, a most interesting mountain region. An intro- duction (48 pp.) describes the physiography, the climate and rainfall, and the zones of vegetation. The zones given are Campestres, Mensales, Sul t , Montanae, Subalpestres, and Alpestres, each with numerous subdivisions. The list of plants (211 pp.) includes 1225 numbers in 486 genera, with a statement as to the habitat of each species. A number of new combinations are made, and = species described in Acomastylis (Geum), Prunus, Vitis, Castilleja, and Grindelia. One of the unique features of the list is that a popular name is 8iven for each species. When this reaches such a stage as “filiform toad- flax-leaved painted cup,” it is probable that it ceases to be useful—J. M. C. Graft hybrids.—Miss Hume" has investigated three graft hybrids for con- uscting protoplasmic threads. The “periclinal chimaeras” used were Cytisus 5% ami, Solanum tubi gense, and S. Kolereuterianum, since in these the epidermis is the only layer of cells belonging to the one component, and the line of de- Marcation between the two components is therefore a sharp one. BUDER ee Igr ie Faaser, H. C. L, The pairing of the chromosomes. New Phytol. 11:58-60. Wai, oa FRANCIS Porter, The flora of Boulder, Colorado, and vicinity. * “Assourl Studies. Science Series 2: no. 2. pp. xiii+311. 1911. oa Pian Marcaret, On the presence of connecting threads in graft hybrids. - 12:216-221. 1913. 166 BOTANICAL GAZETTE [FEBRUARY had already discovered connecting threads between the two components in Cytisus Adami, which Miss HuME confirmed. In Solanum tubingense she found them, while in the other Solanum she did not. These results show that genet- ically unrelated tissues can be joined by connecting threads, and the inference is that such threads do not arise from spindle fibers, since no nuclei of the two components have even been sisters.—J. M. C. The embryo sac of Bellis.—The peculiar development of the antipodal region in some Compositae has long been known. In 1895 the reviewer” described an “antipodal oosphere” in Aster movae-angliae, and nearly ten years later Miss OPPERMAN® not only found an antipodal oosphere in Aster undulatus, but noted its fertilization. Recently, Carano” has described a “pseudo- oosphere’’ in the antipodal region of Bellis perennis. In all these cases, the region in which the abnormal oosphere is found is greatly enlarged; in fact, it has the appearance of anembryo sac. Doubtless the conditions in the enlarged antipodal cell are about the same as in a normal embryo sac, and consequently the occasional organization of an oosphere is not so strange as we formerly supposed.—CHARLES J. CHAMBERLAIN. Reproduction in gymnosperms and angiosperms.—Under this title ERNST” gives an excellent résumé of the present status of the subject. The illustra- tions, which are taken from the leading contributions, are well reproduced. The bibliographies are in two categories: those which treat the subject in & general way, like textbooks, and those which deal with original investigation. The title, Hand dictionary of the sciences, is somewhat misleading for English- speaking people, for this “dictionary” is more like an encyclopedia, consisting of several volumes, edited by a staff of specialists. Oxrmanns is the general editor of botany, and he has distributed the various topics to specialists 1n the various fields. All articles, like the one just mentioned, are signed.—CHARLES J. CHAMBERLAIN. Mitosis in Oenothera.—In the somatic divisions of Oenothera lata GATES® finds the chromosomes forming from the delicate reticulum by the pe el fusion of several strands. No prochromosomes are present, and no continuous spirem is formed. The splitting of the chromosomes occurs in late prophase, *9 CHAMBERLAIN, CHARLES J., The embryo sac of Aster novae-angliae. Bor. Gat 20: 205-212. pls. 15, 16. 1895. » OppERMAN, Marte, A contribution to the life history of Aster. Bot. Gaz. 37:353-302. pls. 14, 15. 1904. d ; 2 CARANO, ENRICO, Su particolari anomalie del sacco embrionale di Bellis perenn’s- Annali di Botanica 11: 435-439. pl. 9. 1913. 22 ErnstT, A., Fortpflanzung der Gy I und Angiospermen. Abdruck aus Handwérterbuch der Naturwissenschaften 4:227—-261. figs. 37- 1013- % Gates, R. R., Somatic mitosis in Oenothera. Ann. Botany 26:993-1°F° pl. 86. 1912. 1914] CURRENT LITERATURE 167 but the split disappears temporarily before the metaphase, when it is again evi- dent. During late prophase and metaphase the chromosomes often show a distinctly paired arrangement. In telophase there is a massing at each pole, after which the chromosomes separate and become joined by anastomoses. Considerable variation in chromosome number is shown; the usual number is 15. The nuclei occasionally show certain characters of heterotypic mitosis.— L. W. Swarr, Poison weed.—Larkspurs have always had the reputation of being poison- ous, but it seems that only in North America have they been important in caus- ing losses of stock. Marsu and his associates’ have investigated the poisoning due to larkspur in Colorado, and presumably the conditions are the same in other mountain cattle ranges of the West. The larkspurs are grouped as tall and low larkspurs, Delphinium Barbeyi representing the first group, and D. Nelsonii the latter. These forms cause the loss of a great number of cattle, but horses and sheep are not injured by grazing on larkspur areas; and cattle are not injured if prevented from grazing on such areas until the second week of y. The next problem is to discover the specific poison.—J. M. C. Xenia.—Having discovered instances of xenia in wheat, BLARINGHEM*S sought to determine whether the vigorous development of hybrid enbryo and endosperm ever causes a change in the character of the maternal tissue that Surrounds them. On crossing a comparatively small wheat, known as Triticum furgidum gentile Al. var. Normandy, with a larger type, Triticum vulgare lutescens hybrid no. 126 of the Hohenheim collection, 16 hybrid seeds approach- ing the paternal variety in size were obtained. This phenomenon is inter- P reted as Xenia in the original sense of the term, though it seems probable that t Is simply a stretching of the pericarp due to a large hybrid embryo and endosperm.—E. M. East. Artificial cell structure.—In a series of interesting experiments, W. MaGnus* nas Produced, from paraffin, beeswax, and other substances, various structures which bear a striking resemblance to cells and tissues. The paraffin, with a melting point of about 74° C., was poured upon mercury which had been heated es 78° C. and allowed to cool at room temperature. While this is only the begin- hg of the investigation, the writer thinks he has already shown that through wé action of purely physical forces structures can be produced which look like «. MARsH, C, Dwicut, Crawson, A. B., and Mars, Haptercn, Larkspur or Polson weed.” U.S, Dept. Agric., Bur.,Plant Ind., Farmer’s Bull. 531. 1913. . ve ae, L., L’influence du pollen visible sur l’organisme maternal; décou- xénie chez le blé. Bull. Soc. Bot. France 60:187-193- 1913- Ma: egg Anus, Werner, Uber zellenformige Selbstdifferenzierung aus fliissiger terie. Ber. Deutsch. Bot. Gesells. 31: 290-303. pl. 13. 1913. 168 BOTANICAL GAZETTE [FEBRUARY cells. Further work is expected to show to what extent the physical forces concerned in the living and inorganic material are identical—Cuar_es J. CHAMBERLAIN, Ovulate flower of Gnetum.—The publication of Miss BERRIDGE’s paper” on the ovulate strobilus of Gnetum Gnemon, in which she gave evidence for the conclusion that the ovule was “‘primitively surrounded by a whorl of male flowers,” has called out a paper by LicNIER and Tison* upon the same struc- ture. They have found material that seems to indicate that the “third integu- ment”’ of the ovule is a modified axis of inflorescence that bore an axillary ovule; and that occasionally an axillary group of staminate flowers is present, which indicates a connection with Welwitschia.—J. M. C. Beech forest on chalk and on schist——Comparing the English beech forests on chalk with the French on schist SKENE” finds that they are exactly similar ecologically, and that scarcely a member of the latter is a calcifugous plant, while scarcely a single member of the former is a calcicolous plant. Topo- graphically there is no distinction between the two types. This leads SKENE to question the accuracy of placing the two forests in different formations according to the classification adopted by British ecologists.—Gro. D. FULLER. A bibliography of mitosis.—A very useful list of works on meiosis and somatic mitosis in the angiosperms since 1880 has been compiled by PicarD.” The forms are arranged according to systematic position. Although the author has not attempted to make the citations on the individual plants exhaustive, the 300 and more citations given justify him in his belief that from the list one can obtain reference to all the literature of the subject.—L. W. SHARP. Embryogeny of the Ranunculaceae.—In continuing his studies of the Ranunculaceae, SourcEs has described the development of the embryo of Ficaria ranunculoides, including some interesting cytological details.—J. M. C- 77 See Bot. Gaz. §5:172. 1913. % LicntieR, O., et Tison, A., L’ovule tritégumenté des Gnet tp axe d’inflorescence. Bull. Soc. Bot. France 60:64-72. figs. 5- 1913- 29 SKENE, MacGrecor, The relation of the beech forest to edaphic factors. Jour. Ecol. 1:94-96. 1913. % PrcarD, M., A bibliography of works on meiosis and somatic mitosis in the angiosperms. Bull. Torr. Bot. Club 40:575-s90. 1913. 3 SouBGES, R., Recherches sur l’embryogénie des Renonculacées. Bull, Soc: Bot. France 60:150-157. pl. 11. figs. 288-315. 1913. hahleoment un Volume LVII Number 3 Wf THE BOTANICAL GAZETTE Editor: JOHN M. COULTER MARCH 1014 The Anatomy of Ophioglossum pendulum Loren C. Petry Some Effects of Colloidal Metals on Spirogyra W. D. Hoyt The Function of Manganese in Plants W. P. Kelley The Development of the Prothallium of Camptosorus rhizophyllus ¥F. L. Pickett Current Literature The University of Chicago Press CHICAGO, ILLINOIS, U.S.A. Agents THE CAMBRIDGE UNIVERSITY PRESS, London and Edinbersh LO NEEL © 908, Lanier - i THE Mi RUZ! ts | Tokve, Ovake, Kyoto ze ce oy 2 The Botanical Gazette A Montbly Journal Embracing all Departments of Botanical Science Edited by JoHn M. CouLter, with. the Rear of rsa members of the botanical. staff of the University of Chi See March oe ais . ; - Vol.. LVII .. CONTENTS FOR MARCH 1914 No..3 THE are: OF OPHIOGLOSSUM PENDULUM. ee FROM THE HULL CAL LABORATORY 183 (WITH SIXTEEN FIGURES). © Loren C. Petr “ 169 SOME EFFECTS OF COLLOIDAL MET! ALS ON SPIROGYRA - ITH FOUR ie W. D. Hoy, 193 THE FUNCTION OF MANGANESE IN PLANTS. W. P. Kelley- > - - - - toa the THE DEV ELOPMENT OF THE PROTHALLIUM OF CAMPTOSORUS RHIZOPHYLLUS : (WITH PLATES KI AND XII AND EIGHT TEXT FIGURES). F. L: Picketi * - * “CURRENT LITERATURE EWs - “3 ~ = is as - e et is 2 = Si OR 5 GENETICS. : MINOR NOTICES nh eae i z € e se AEBS = : ‘Jb that it has developed from a bud; | fig. 5 represents such a case. Rostowzew (7) has described the development of the bud in O. oul- oe ae eee Saium. In the second segment of or Prise a, stem tip; /b, the apical cell of the root a new base of a decayed leaf; r, parent apical cell arises; this produces all root; Xr. stem tissues. The root apical cell is retarded for a time, but finally resumes growth. This results in the formation of a bud with its axis approximately at right angles to the parent root. __ The development of the bud has been examined in O. pendulum; t agrees in all important points with that of O. oulgatum. The retardation of the root growth is usually less; the bud axis often diverges less abruptly from that of the root. Two roots usually develop upon a bud before the first leaf is formed. The details of © vascular connection between the stem developed from a bud and the parent root will be described later. -----a 176 BOTANICAL GAZETTE [MARCH The stem The largest rhizome of the Australian material measures 0.7 cm. in diameter and 2.5 cm. in length. There are 18 leaves still attached and the bases of 5 others are evident. All the rhizomes, with the exception of the very youngest, give evidence of having grown in a horizontal position; field observations by Dr. CHAMBER- LAIN confirm this. The leaf bases, however, are not restricted to the dorsal side, as stated by CAMPBELL (3) for this species, but are attached in a spiral about the stem. The distribution is irregular; on young stems the leaves are rather crowded and attached along a spiral with about a 4 arrangement. On older stems the distri- bution approximates a ? arrangement; fig. 6 shows the arrangement of the leaves on the largest specimen De ne secured. The bases of the leaves in- FE een s serted on the lower side curve round HEISE for ae ANN \ the rhizome and produce the appear- tot i Pie yeh ance of a 2-ranked arrangement, as BAA Seige P in Helminthostachys; but there is EN re ony nothing in the insertion of the leaves [eae ohare or the structure of the stem to indi- be ems cate true dorsiventrality. Fic. 6.—Diagram of leaf ar- The rhizomes of the Samoan ma- eae: . Se em tertal we decidedly larger than those from Australia; the oldest one secured, with 8 functional leaves and 7 leaf bases, was 1.2 cm. in diameter and 4.6 cm. in length. Both their appearance and their structure indicate a definite radial arrangement (fig. 5). The leaf insertion is similar to that of the Australian epee but the leaves are less crowded. All the rhizomes in which the bases are me give evidence of having developed from buds upon roots in the manner described above. The connection of the stem stele with that of the root was examined in 12 specimens; five methods of development of the stem stele were found. In a single specimen, a solid strand of xylem, surrounded by phloem and endodermis, separates at a considerable angle from one of the protoxylem strands of a tetrarch root (fig. 7). The endo- 1914] PET RY—OPHIOGLOSSUM PENDULUM 177 dermis soon disappears; before separation from the root stele is complete, a few cells of parenchyma appear near the center of the xylem mass (fig. 7, C). The number of these increases and a definite pith is established (fig. 7, D). A small gap opens through the xylem, and closes again almost at once; the phloem is not interrupted. The xylem cylinder dilates rapidly and becomes oval in section; root steles attach at the points of the oval, leaving large “root gaps”’ in the cylinder (fig. 7, L). A third root attaches between the two gaps (fig. 7, M), producing a small gap; the three gaps close at about the same level. The first strand of the trace SO S Sasa 3 ASS Fic. 7-—Development of stem stele from a single strand; only the xylem is shown: r, tetrarch stele of parent root; rt, root trace; rg, root gap; /s, first strand of first leaf; x12, : of the first leaf separates from the cylinder at a slightly higher level (fig. 7, N). This is essentially the course of development of the stem stele of O. vulgatum from a bud. In five cases, two strands of xylem of varying shape in cross- Section separate from two of the poles of a triarch or tetrarch root. Stams of sections of one of these specimens are given in fig. 8. Each strand at the point of junction with the root stele has phloem On two faces, or surrounding it; the phloem disappears almost immediately from the adjacent faces and becomes restricted to the “xterior sides of the strands. After an interval the two strands 178 BOTANICAL GAZETTE [MARCH fuse at one margin, forming a half-cylinder of xylem (fig. 8, £). Two roots are usually given off somewhat farther up (fig. 8, J), and the margins of the gap come together at about the level of the base of the first leaf. In a single instance, three strands arise from the three poles of atriarch root. These fuse just below the point of connection of the first root to form a large strand of semicircular cross-section. The gap between the margins closes just below the level of the first leaf. In another specimen, two strands separate from each of two of the 1G. 8.—Development of stem stele from two strands; only the xylem is shown: px, protoxylem strands of parent root; rt, root traces; X12. protoxylem strands of a tetrarch root. These four organize a stele in the manner described above; the opening in the side is closed rather late, at the level of the top of the first leaf gap. The stem stele is organized in a distinctly different way in four cases. A series of sections through one of the specimens from below upward is shown by fig. 9. In this case, the xylem mass of one pole of a diarch root begins to enlarge (fig. 9, A-C). After 4 time, medullation of the enlarged xylem strand occurs by the appearance of parenchyma near the center (fig. 9, D, £, fig 10). The endodermis disappears on the side away from the unchanged 1914] PETRY—OPHIOGLOSSUM PENDULUM 179 pole of the root. At the same level, gaps appear in the sides of the cylinder (fig. 9, G, H,) and the xylem separates into two strands. The smaller of these (r, fig. 9, H) is the continuation of the original root, and at once resumes its original diarch character. The larger strand organizes itself into the stem stele. The three strands of the first leaf separate (fig. 9, 7, J), and at a slightly higher level (fig. 9, J, K) two roots are attached. The stem stele at this point \ \ : \. A J “Sap y, k®& << LL ants. 9.—Development of stem stele by medullation of root stele; only the xylem 's shown: r, stele of parent root; rt, traces of first roots of new stem; /t, trace of first leaf; X25 Consists of three strands (fig. 9, L), which organize the mature form of the stele in the usual way. In the other rhizomes showing manner of development, the original root is triarch or tetrarch; . after separation from the stem stele, the root stele usually shows ‘n Mcreased number of protoxylem strands and the medullated condition shown in fig. 4. In all cases, the stem stele soon assumes its usual form, that of an ectophloic siphonostele with more or less overlapping leaf gaps 180 BOTANICAL GAZETTE [MARCH (fig. 11). Two gaps usually occur in the same transverse section, and cause the xylem of the stem to appear as two curved masses with concave sides facing (fig. 11, G). Often only a single gap interrupts the cylinder (fig. 11, A), or the section may show a com- plete ring of xylem (fig. 12, C); very rarely, three gaps overlap. The leaf gaps are circular or oval and usually very large; 2 mm. in width by 2.5 mm. in height is an average size. The largest observed measures 3.23.5 mm. In general the stele is more compact and shows more definitely its cylindrical char- acter than in O. vulgatum. It is often very irregular in out- line; the insertion of leaf and root strands usually produces a modification of shape, as shown in figs. 11, 7; 12, E; 7, J, K, etc. It is usually not straight, but slightly bent at each leaf gap in the direc- tion away from the leaf; this is undoubtedly due to the pressure of the young leaf. In diameter the stele is usually a little less than half that of the rhizome, that is, 3-5 mm. . eae, of E, fig. 9: x, xylem; Besides these leaf gaps, clon, wempeeee: eee Sbeuings Selmicly 7 roots occur in the cylinder (figs. 7, J, 0; 8, J, KR; ix, B,C, J). These are more conspicuous in the larger rhizomes, where a gap occurs above each root; in the smaller specimens, gaps occur in connection with about half of the roots. These openings are narrower in proportion to their length than are the leaf gaps; they range in size from 0.20.4 mm. to o.5X2mm. Where a root is attached to the cylinder immediately below the point of insertion of a leaf, a gap is almost invariably produced; the leaf strands attach to the sides of this gap, which is therefore continuous with the leaf gap. In cases of this kind, 2306 ry QRS feet tits caries 1914] PETRY—OPHIOGLOSSUM PENDULUM 181 the gap in the cylinder above the insertion of a root might be inter- preted as the beginning of the leaf gap; but in very many cases openings of an exactly similar nature occur when only a root is involved. These gaps close in the same manner as leaf gaps; for convenience they may be referred to as root gaps. Fic. 11.—Stele of mature rhizome, showing various openings in the cylinder; the xylem is shown: rg, root gap; rt, root trace; ig, incidental gap; /g, leaf gap; ls, leaf strands; X4.5. In addition to these, openings not related to outgoing strands often occur in the cylinder (fig. 11, B-F). These incidental gaps Sometimes occur at the margin of a leaf gap; a strand separates from the margin of the gap, runs parallel to it for a time, and later 182 BOTANICAL GAZETTE [MARCH fuses with it. At other times, a long narrow slit may occur in the cylinder. Some of the gaps are relatively large, measuring 0.6X o.7mm. Apparent gaps, due to a failure of the xylem parenchyma to lignify, sometimes occur; in these the phloem is not interrupted. In most of the incidental gaps, however, the cortical parenchyma connects with that of the pith, as in leaf and root gaps. Lignification occurs first in the layer of tracheids nearest the pith; these first xylem elements differ in no way from those outside. They are true tracheids, often very irregular in shape; lobed and even branched forms occur. They are relatively short, 3-6 times as long as broad; the walls are reticulately thickened. The ligni- fication does not begin at definite points, but indiscriminately throughout the inner layer. It proceeds in an outward direction; in the mature stems the xylem is 5 or 6 tracheids in thickness. Occasional irregular divisions occur within the procambium strand after lignification has begun, but there is no true secondary thick- ening. The phloem is uniformly a single layer of cells; it is separated from the xylem by a layer of parenchyma 3-5 cells in thickness. There is no endodermis except in the extreme basal region and at the points of attachment of roots; in these instances it is a mere exten- sion of the root endodermis, and is not to be considered as related to the stem stele. The phloem abuts directly upon the cortical parenchyma composed of large spherical or ellipsoidal cells with intercellular spaces; the cells of the layers next the phloem are some- what smaller than those farther out. The walls of all the cortical cells are secondarily thickened with cellulose, as in the inner region of the root cortex; the pits are much larger. The pith is in all respects similar to the cortex; the cells of the layers next the xylem are considerably smaller than the average. There is no starch storage in any part of the plant, but fats occur in some quantity in all parts, especially in the pith and cortex of the stem. The growth of the stem is by a tetrahedral apical cell, as in other species of the genus; its segmentation was not examined. The largest rhizome of the Australian material presents 4? interesting variation of this usual situation. The base has decayed and it is impossible to say whether the stem originated from 4 1914] PETRY—OPHIOGLOSSUM PENDULUM 183 bud or not. In the lowest part, the cylinder is already definitely organized and of the full diameter. There are five gaps corre- sponding to leaves that were no longer attached, and 18 leaves were still in position. This is almost certainly the oldest specimen secured. Up to the level of the fourth leaf gap, the stem cylinder agrees in all details with the usual form, as described above; but about midway of the gap, a strand of xylem separates from the margin of the gap, swings over to the center of the opening, broadens, and by connection with the xylem at either side closes the gap. The gap of the sixth leaf is closed by a similar strand. The gaps of the fifth and seventh leaves are closed in a similar manner by strands which arise as procambium in the parenchyma of the openings. At the level of the fourth leaf, a strand separates from the inner surface of the cylinder opposite the point of connection of a root. This strand runs in the pith near the middle of the cylinder for a dis- tance of about 4.5 mm. and finally closes the gap of the eighth leaf In the manner described. In addition to these five strands, there are in this portion of the stem seven others which arise as pro- cambium or by separation from the inner surface of the cylinder and disappear in the same way, without being in any way related to leaf gaps. One of these closes an incidental gap of the cylinder. From the level of the eighth leaf to that of the twelfth, there are no medullary strands, and the stele presents the usual appear- a At this point another system of seven strands appears; their positions and behavior are shown in fig. 12. Between the Seventeenth and twentieth leaves, no medullary strands occur; ut at the level of the latter, three more strands appear as pro- Cambium in the pith. One appears in the opening caused by the twenty-first leaf and closes that gap; another appears in the center of the base of the twenty-second leaf, and moves inward and closes the gap. The third, arising near the center of the cylinder, branches once or twice; one branch is recognizable as a procambium strand at a short distance from the apical region. In all, 23 medullary strands occur: 16 arise as procambium in the pith, 5 as branches from the inner surface of the cylinder, and 2 as branches of other strands; 9 of them are concerned in the 184 BOTANICAL GAZETTE [MARCH closure of leaf gaps, 7 fuse with the inner surface of the cylinder, 4 disappear by fusion with other strands, and 3 disappear by the gradual fading out of the procambium. They range in length from N WFso Fic. 12.—Stele with medullary strands; only the xylem is shown: m, first medul- lary strand; X4.5. 1914] PETRY—OPHIOGLOSSUM PENDULUM 185 3 or 4 tracheids up to 5.4 mm. in the case of the strand concerned in the closure of the gap of the fifteenth leaf, as shown in fig. 12. A cross-section of one of the strands is shown in fig. 13; they con- sist of xylem and parenchyma, without a trace of phloem. The largest show 30-40 tracheids in cross-section; 8-12 tracheids is the usual size. No protoxylem can be identified; the tracheids all resemble those of the cylinder. Fic. 13.—Detail of a medullary strand; 236 in only one other rhizome was anything of this nature observed. This specimen is from Samoa, and has only three leaves; the base 'S preserved and shows its origin from a bud. At the level of the second leaf a small strand, consisting of a few tracheids only, arises * * procambium at a short distance from the inner surface of the cylinder. It very soon fuses with the cylinder but remains evident “$ @ ridge for a considerable interval. Fron the point of its “ppearance to that of disappearance is about 0.35 mm. 186 BOTANICAL GAZETTE [MARCH The leaf The relation between roots and leaves is very variable. Two or more roots usually appear on the buds before the formation of the first leaf. In the mature stele, roots often connect with the cylinder immediately below a leaf gap; but it is equally common to find two roots attached at the sides of the base of a leaf. No definite relationship between the two can be shown. As already stated, the leaves in exceptional cases reach a length of 2.7 meters. The stout circular or oval petiole may measure I cm. or more in diameter and merges insensibly into the blade; the latter in unbranched leaves is 2~3 cm. in width, but in branched or lobed leaves may reach 5 or 6 cm. at the point of division. Branching and lobing of the leaf occurs very commonly in the Samoan material; in all cases the separation occurs beyond the point of attachment of the fertile spike. There is no absciss layer, a5 described for Botrychium virginianum by JEFFREY (4). ; In the bud, the tip of the leaf 1s curved over; the fertile spike when Fic. 14.—Rhizome with fitst recognizable is attached just young leaf: s, fertile spike; X1. beyond the curve, with its tip directed toward the stem. The original de- velopment of the leaf is by an apical cell, but its later enlargement is by intercalary growth. As indicated by fig. 14, this begins at the base and proceeds toward the tip. The portion between the spike and the stem may be 4-5 cm. in length when the portion beyond the spike is only 2-3 mm. long. In the mature leaf, the spike is attached at a point about one-third of the way from the base to the tip of the leaf. The number of strands separating from the cylinder to cop” stitute the leaf trace varies from 3 to 12; 5 is the commonest number. There is a general relation between the size of the leaf, the size of the gap, and the number of strands. The strands usually attach to the cylinder in a circle, the uppermost one after 1914] PETRY—OPHIOGLOSSUM PENDULUM 187 the leaf gap is actually closed (fig. 12, P; fig. 11, J); in some cases, however, all the strands connect within the lower portion of the opening in the cylinder. The general course of the strands in the leaf base is at a slight angle upward from the point of connection with the cylinder; in very large leaves, the lower ones may run horizontally or even in a downward direction. Branching of some of the strands usually occurs within the cortex of the stem, so that as many as 20 strands may be found in the base of the petiole. This may not occur in small sterile leaves, so that a section of the petiole may show as few as 3 strands. In the sterile leaves, the strands, 3-5 in number, arrange them- selves in the shape of a C, with the opening directed adaxially. The strands in the extremities of the arc in passing up through the petiole swing out toward the margins as the blade is formed, and all come to lie in a single plane with xylem adaxially directed. Frequent branching and anastomosing of the strands occur, so that € number may reach 15 or 20 in the blade of the leaf. In the fertile leaves, the strands, 4-12 in number, are arranged in a circle or oval as they leave the cylinder, and they maintain this arrangement through the petiole. They branch and anastomose freely, forming a complete cylindrical network; no strands connect actoss the circle. As the petiole broadens and flattens, the strands arrange themselves in two series: the outer, consisting of 10-15 strands with xylem directed adaxially, form the vascular system of the blade; the inner series, of 5-8 strands with xylem abaxially directed, is reduced by fusions to 4-6 strands which form the vas- cular supply of the spike. Anastomosing and branching occur 48 before within each series, but there is no further connection between the two systems. Beyond the point of connection of the fertile spike, the single series of strands constituting the reticulate Veining of the blade may increase to as many as 30 in branching leaves. They form a closed system with the exception of a very few small branches which end blindly in the tip, In the leaf strands as they separate from the cylinder, the xylem elements are all alike, but in the base of the petiole and through- Out the leaf the first formed elements can be distinguished by their 188 BOTANICAL GAZETTE [MARCH smaller size. These protoxylem elements are spiral vessels; they always occur at the inner margin of the xylem, that is, in the endarch position. The protophloem, consisting of 3 or 4 cells, develops at the opposite limit of the strand; the later developed phloem of 6-10 cells is arranged in 2 or 3 layers. One or two layers of parenchyma separate the xylem and phloem in a mature bundle (fig. 15). In the mature strands of the blade, and, to a less extent, of the petiole, a definite bundle sheath is devel- oped by the thickening of the walls of 2 or 3 layers of parenchyma surrounding the vascu- lar elements (fig. 15). The thickening material is cellulose and the walls are pitted as in similar tissues of the stem and root. This bundle sheath is separated from the protoxylem by 2 or 3 cells of parenchyma, but borders directly upon the protophloem. As a consequence of growth within the bundle sheath, the protophloem in a mature strand is crushed against and between the cells of the sheath. Fic. 15.—Detail of a leaf strand: pph, proto- phloem; ph, metaphloem; px, protoxylem; x 236. The spike As stated above, the strands of the leaf with xylem directed abaxially form the vascular supply of the spike. At the base of the peduncle these are 4-6 in number; they continue with occa- sional anastomosing and fusion through the median portion of the spike. At the base of the fertile portion of the spike, the strands at the margin of the median region run immediately at the base 1914] PETRY—OPHIOGLOSSUM PENDULUM 189 of the sporangia. Farther up the spike, where the ridge of sterile tissue which extends into the spore mass is well developed, the strand occupies a position well within this ridge (fig. 16, B). There is no branching of the marginal strand below the first few sporangia; but between the third and fourth sporangia, a short lateral branch extending halfway to the edge of the spike usually occurs. Similar strands occur between all the sporangia above this point (fig. 16, They consist in cross-section of 10 or 12 tracheids, and occupy the center of the thin wall separating adjacent sporangia. Near the margin of the spike they spread out in the shape of a fan and end blindly (fig. 16). The central strands are reduced by fusion to a single strand when the tip of the spike is reached. Between the ter- minal sporangia this splits into two Strands which run out above the sporangia and end in the fan-shaped arrangement described above. The strands of the peduncle and of the median region of the spike show the same structure as those of the blade of the leaf , but the bundle Fic. 16.—Diagrams of vascu- sheath is much less developed. In _ ler system of the _, cpr : itudinal section; B, transverse - . i. ee coe erate se C, transverse . section in plane aa; X4.5. Protophloem is on the adaxial side of the xylem, but the later developed phloem elements may extend in the shape of a U about the xylem, which is always endarch. In the fan-shaped portion of the strands the phloem cannot be distinguished ; there is no distinction between protoxylem and metaxylem. Discussion The most striking characteristic of the anatomy of this species the extreme variability of certain structures. The number of _Protoxylem strands of the root and the number of strands consti- tuting the leaf trace vary almost directly with the size of the organs concerned. The external conditions which determine whether the is Igo BOTANICAL GAZETTE [MARCH stems are large in diameter or small determine in the same way the number of the strands of the leaf. Such variations may be con- sidered as produced directly by growth conditions and therefore of physiological interest only. The variability in the connection of the stem stele with that of the root is related to the position in which the bud develops; thus, the bud which developed the stem stele shown in fig. 7 was located directly over one of the protoxylem strands of the root, while that of the specimen shown in fig. 8 was placed midway between two such strands. In the same way, the condition represented in fig. 9 may be ascribed to a more gradual divergence of the root and stem axes; for a time, the two apical cells formed a common tissue within which a single stele was developed, as in fig. ro. When the angle be- tween the two axes became greater, separate steles were developed. It is of course impossible to say what determines these relations of position of the protoxylem strands and the stem meristem, oF the rate of divergence of the two axes; but it seems evident from these variations that the manner of development of the stem stele in a bud is controlled by chance or external conditions. Hence we may conclude that the stelar characters shown in the develop- ment from buds cannot be used in any discussion of phylogeny: It is to be noted, however, that two features are constant; these are the collateral arrangement of the stelar elements and the endarch position of the protoxylem. The occurrence of occasional strands of xylem in the pith is a feature that is unique, so far as the writer is aware. The manner of origin of these strands and their behavior suggests somewhat the medullary strands of Marattia; but the absence of phloem dis- tinguishes sharply between the two cases. In any consideration of this feature it should be borne in mind that these strands occur t0 any considerable extent in only a single specimen. LANG (5) from a study of Botrychium Lunaria has concluded that the pith of Ophioglossaceae is purely intrastelar in origin. This opinion is based in part upon the occurrence of scattered tra- cheids in the pith, particularly in injured rhizomes; this formation of xylem elements from parenchymatous cells of the pith is con- sidered strong evidence of the stelar origin of the pith. The medul- 1914] PETRY—OPHIOGLOSSUM PENDULUM IgI lary strands of O. pendulum afford a much more definite case of this sort; they are in no way a traumatic response; cells of the pith develop a procambium which develops into xylem only; this may be taken to indicate that all cells of the pith are potentially xylem- producing, and therefore stelar. Summary 1. The root stele varies from diarch to hexarch. The roots branch monopodially, and the branches are diarch at the base. 2. Buds develop upon the roots in the same manner as in O. vulgatum. 3. The rhizomes are always radial in structure; the leaves are inserted in an irregular spiral. 4. The connection of the stem stele with that of the parent root is very variable ; no phylogenetic significance can be attached to the details of development of the stem stele of a bud. 5. The stele of a mature rhizome is an ectophloic siphonostele with large overlapping leaf gaps; there is no secondary thickening. Root aps usually occur above the points of insertion of root strands. Incidental gaps not related to outgoing strands occur commonly. In a single large rhizome, numerous xylem strands occur within the pith. These arise from the inner surface of the cylinder °r aS procambium; some of them are concerned in the closure of leaf gaps, and others disappear as procambium or by fusion with the cylinder. They consist of xylem only. 7. The vascular supply of the leaf consists of 3-12 strands, the number varying with the size of the leaf base. ‘These strands form @ cylindrical network in the petiole; in the lower portion of the blade, they constitute two series of strands with xylem oppositely directed. The strands with xylem abaxially directed form the vascular supply of the spike. The writer is indebted to Professor Joun M. CovuLTEr for many Suggestions and criticisms; and to Dr. CHARLES J. CHAMBERLAIN end. Dr. W. J. G. Lanp for the material used and for direction during the investigation. Tre University or CuIcaco 1g2 BOTANICAL GAZETTE [MARCH > be un n I LITERATURE CITED - Bower, F. O., Studies in the morphology of spore-producing members. II. Ophioglossaceae. London. 1806. phioglossum simplex. Ann. Botany 18:205-216. pl. 15. A CAMPBELL, D. H., The Eusporangiatae. Carnegie Inst. Pub. 140. * Wash: ington. 1911. JEFFREY, E. C., The gametophyte of Botrychium virginianum. University Toronto Studies 1:1-32. pls. 1-4. 1898. - Lanc, Wa. H., Studies in the morphology and anatomy of the Ophioglos- saceae, I. On the branching of Botrychium Lunaria, with notes on the anatomy of young and old rhizomes. Ann. Botany 27:203-242. figs. 14. pls. 20-21. 1913. . » PRANTL, K., Systematische Ubersicht der Ophioglosseen. Ber. Deutsch. Bot. Gesells, 12348-353. 1 83. > reel S., Recherches sur l’Ophioglossum vulgatum L. Oversight. K. D. Vidensk. Selsk. 1891: 54-83. figs. 1-17. pls. 1, 2. SOME EFFECTS OF COLLOIDAL METALS ON SPIROGYRA!? W. D. Hox? (WITH FOUR FIGURES) The effects of colloidal metals on the activities of living cells. seem to have received but little attention, although it appears that studies of such effects should yield results of importance to pro- toplasmic physiology. We regard protoplasm as largely composed of colloidal material, and believe the enzymes affecting many of the protoplasmic processes to be colloidal in their nature. Further, we know that, outside of protoplasm, colloids affect one another in many different ways, and that colloidal metals are capable of bringing about reactions which are similar, in many respects, to those usually related to the action of enzymes. It becomes a matter of considerable interest, therefore, to determine the effects of colloidal metals on protoplasm and protoplasmic products, especially since the soluble salts of many metals are known to be extremely poisonous. The phase of the problem thus suggested with which the present paper has to deal may be stated as follows: Solutions of the salts of silver, gold, and platinum are poisonous to Protoplasm; colloidal solutions of the metals named may bring about reactions in non-living materials similar to those caused by enzymes; what, then, may be the effects of such colloidal solutions on protoplasm ? The present investigation was planned to obtain some prelimi- oy information bearing upon the answer to this question. It has mainly to do with the descriptive aspect of some of the superficial effects of colloidal solutions of platinum, gold, and silver on two Species of Spirogyra, with a few notes on other algae. The work Was undertaken at the suggestion of Professor GEorG Kies, and Was carried out in the Botanical Institute of the University of in * Botanical contribution from the Johns Hopkins University, no. 30. These tans. were carried on while the author held the Adam T. Bruce Fellowship of : opkins University. A summary of the results was presented before the Society of America at its Washington meeting, December 28, 1911. 193] (Botanical Gazette, vol. 57 194 BOTANICAL GAZETTE [MARCH Heidelberg. Unless otherwise stated, the species used was Spiro- gyra longata (Vauch.) Kg. The material and general methods were the same as those described in a previous paper (8). The original culture of Spirogyra longata was brought from Algiers, but the alga had been growing for nearly three years in the laboratory, in a stock culture which received small additions of tap water from time to time. The filaments of this stock culture were apparently healthy and of the usual appearance. The colloidal solutions of silver, gold, and platinum here employed were made with non-toxic water, according to the method previously described, of distillation in glass with animal charcoal present in the retort. They were kindly prepared for the author by Dr. W. FRAENKEL in the labora- tory of Professor G. BREDIG at the University of Heidelberg, by atomizing the metals with an electric arc under water. This method has been described by BREDIG (2, 3,4). The solutions were kept in flasks of Jena glass. Those of gold and platinum were determined by Dr. FRAENKEL and found to contain go ppm. (parts per million) of gold and 96 ppm. of platinum, respectively. The sample of the silver solution was unfortunately lost before being determined, but, as all three solutions were originally prepared so as to contain the same amounts of metal (with an error not greater than 10 ppm.), the concentration of the silver solution here employed may be considered as approximately go ppm. The solution of gold was purple in color, that of platinum was yellow-brown, while the solution of silver was grayish brown. The gold solution, on stand- ing, formed a deposit, probably of the larger particles, on the walls both of the flask containing the stock solution and of the culture dishes, but the intensity of its color was not perceptibly diminished by this deposition. The solutions of silver and platinum gave 2° observable deposits. In considering the results obtained with these solutions, the possibility is not to be forgotten that small amounts of metal oxides may have been formed in the process of preparation, and that the solutions are not to be considered as necessarily am entirely free from metal in the ionic condition. Colloidal solutions of silver, gold, and platinum prepared by Brevi, similar to those used by the author except that they were weaker and were not made with carbon-distilled water, wet 1914] HOYT—COLLOIDAL METALS “ 195 examined by ZsIGMoNDy (17) with the ultra-microscopic apparatus devised by him. From his results it was calculated that the diameters of the particles in the silver solution were about 50-77 uu. The gold solution contained particles 20-80 uy in diameter, the larger ones being separable by filtration. There was a much greater range in the size of the suspended platinum particles, but by far the greater portion of these were very small and had an average diameter of 44 uu. As the solutions employed in the present investigation resembled in appearance those described and examined by Zstcmonpy, it is probable that the particles in these solutions had a similar degree of magnitude. The results upon toxicity obtained in the present investigation are shown in tables I-IV, which are self-explanatory. In the following consideration of the main points the Roman numerals in parentheses refer to the tables and the Arabic ones to the experi- ment numbers as there given. The solution of silver was extremely toxic (I, 1), killing the alga within 17 hours in concentrations above 0.045 ppm. (0.05 per cent of the solution originally prepared) and injuring many of the fila- ments in strengths as low as 0.00225 ppm. (0.0025 per cent of the original solution). In filaments thus killed the cell contents were often dark and disorganized and were more or less contracted. Various substances were added to the colloidal silver solution to determine the effect of their presence upon its toxicity. The addi- tion of salts to form a o. 5 per cent concentration of Crone’s nutrient Solution? to colloidal solutions of silver in concentrations of 0.045 ag or less (I, 2), produced marked improvement, as did also the addition of about 81 ppm. colloidal platinum (I, 3), or of about 0.1 * animal charcoal (I, 4). Solutions which had previously been mjurious or fatal were thus changed into solutions which were ‘ntirely or almost entirely non-injurious during the period of the ®xperiments (1—3 days). In such cases the cell contents retained their usual healthy appearance. € effect of the gold solution shows that it was much less toxic than that of silver. In order to obtain colloidal gold and hold it in i. “ng amen contained salts in the following proportions: 1 gr. KNO;; 9.5 # ©.5 gr. CaSO,; 0.25 gr. Ca;(PO,)2; 0.25 gr. Fe;(PO,)2. 196 : BOTANICAL GAZETTE © [MARCH solution, about 0.02 per cent of sodium hydroxide was added to the water with which the colloidal solution was prepared, so that this solution contained NaOH. Two experiments were carried out with TABLE I CULTURES OF SPIROGYRA LONGATA IN COLLOIDAL SILVER SOLUTION, WITH AND WITHOUT ADDITIONS Silver in medium, | Other substancesin| Condition of Duration of Culture no. ae apa oe plants* experiment, days* Te Ce OOO ae ee DD I,1 Ticks 0 D 1 cS. GS ee D I 16 eee Bees ae ees ee D I | een ea ee Oe or eee a ac D I » | SERS Te aA ia coo Aaiageus urinates, SEN ere gem D I sf yen es eaten ee Sie ONG. he Po ey Pb 1,1 SAG Ra gt Se TE, SOO selee Bageaes nt E t st Soe hay cere D009 ee Gp 3 iF Pied ete eg I OORR— a oe E . 10 pay ae pee O- OOS hi ten ei G, D 3,1 ey Se arate eee re 0.045 Salts to form E, Eg 2,1 0.5 p.c. Crone’s solu- tion Me 0.0135 : E t Bik See 0.009 do. Eg 3 Me ©.0045 do. E cele Cette enon 0.045 Colloid. Pt, 81 E,E 2,1 ppm. eee aaa tra 0.0135 do. E CeO oe ©.009 do. E 3 See ee 0.0045 do. E : 4B ie 0.045 Animal char- coal, o.1 gr. E, G 2,1 Pe Se ors 0.0135 do. E . Mio ee 0.009 do. E 3 Ads ae 0.0045 do. E : [ee *In tables I-IV th Ate: +h oe a ee ee E, excellent, meaning that none of fil nts i * i; G, good, : ee - LW 3 2. j a D ig poor, . more than half i injured; D, dead, meaning that all or practically all the filaments were dead. : Where the experiment was repeated, estes e several notations g fers to a single exp t. The numbers in the last column (duration i ° £ } denoting duration Pee a 4 i } ; thus, . combination of letters denotes a condition between those denoted by the combined letters, S Eg Aiti. het oll, a good. fuk etc. cod Spirogyra from the stock culture, filaments being transferred to the undiluted, alkaline solution of colloidal gold (II, 5a). In one case the filaments remained in excellent condition during the period of the experiment (2 days); in the other case, the alga remained with- 1914] HOYT—COLLOIDAL METALS 197 out apparent injury for 5 days, except that the chloroplasts dwindled slightly; but on the sixth day, when the experiment was discon- tinued, many filaments were dead. For comparison with the above, two experiments were performed with Spirogyra which had grown TABLE II CULTURES OF SPIROGYRA LONGATA IN SODIUM HYDRATE SOLUTION, WITH AND WITHOUT COLLOIDAL GOLD AND OTHER ADDITIONS © eas —— substances in Cosidtiion of Duration of ‘ = mn nm oO! i | Watt. per cont?.|_ mate aeoente. "plants experiment, days ppm, es a. 0.02 Colloid. Au, E, Eg 2,6 90.0 | ae 0.02 Colloid. Au, re, F 3,4 [Plants from o.1 re) p.c. Crone’s sol., 72 days old] aes 0.01 Colloid. Au, Gp @ 6 7 . ey 02 Sesto ue nna D - i ag Oe ee _ Pd 5 ae 0.01 Colloid. Pt, E 5 48.0 . eee 0.02 Colloid. Ag, D 0.0135 ee... 0.02 Colloid. Ag, Pd . 0.009 ee 0.02 Colloid. Ag, Gp 9.0045 = 7 oa 5 i eae PGE eae ee Aone oS Eg, D hd 0 a OE ep ee ea E, Eg yi doe Re: 0.02 AuCl,, 100.0 Se orf, nee Re 0.01 AuCl, 100.0 Eg, Gp das ee 0.02 Colloid. Pt, E,G eA 86.4 ng a 0.01 Colloid. Pt, E,E fi 86.4 Th eine iarieipsaiay 8 * The andi: ei? ay Par s. eta oie PEt 1 ee eae et an a tion a i 5@-9¢ P ay “i = the colloidal gold solution; that used in cultures ro-12b was prepared at another time. The Strength of the ¢. Sek 2 ; SEE SPE ieee Scneoarae ts tely t mat Unless otherwise noted, the material of S pirogyra used in these experiments was from the stock me O.2 per cent Crone’s solution for 72 days. The filaments were . i non-toxic water and placed in the undiluted gold solution (H, 56). In one case, the filaments remained in excellent condition two days, but a few showed injury on the third day; in the other “Ase, the alga remained in excellent condition one day, but on the 198 BOTANICAL GAZETTE TABLE III hie CULTURES OF SPIROGYRA LONGATA IN COLLOIDAL PLATINUM SOLUTION, WITH AND THOUT ADDITIONS Platin medium, Other substances in Durie Culture no. approximately, got gn ag Condition of plants cupeenenaa poe 1s Bag ae ie Re.” Oe ee eats Oe Eg, E 22,3 TAG on ees 86.4 ECL 6:2 ig 12 PAD ace i fe tir oe ep do., control to Pd 6 I Pebs est et 86.4 MgS04, 0.02 Gp 19 ECR SARC tenes ee re oe ener eer do., control to Pd, D 6, 2 100 48.0 Tap — 50.0 G 20 TOR Cees Se Pe eee do. trol to Pd 12 Pe TOG ee 48.0 Ord. dist. H.O, Gp 26 ROG G8 ee ale ee see do., control to DoD. Pp 2,1,1 I ay eek et ea rc, ©; cok. Pd 12 MgSO, o po ee TABLE IV CULTURES OF SPIROGYRA DECIMINA (NOS. 18-23b) AND OF OSCILLATORIA (NO. 24) IN Co) UM HYDRATE SOLUTION, WITH AND WITHOUT ADDITIONS Sone aa _— substances in Duration of Culture no. NaOH, per pect’ sacs ee ae mabe Condit f plants) experiment, days m. se ait 1S Ase 0.02 Colloid. Au, Pd 4 90.0 10... CrOne oer ee Pd = 20.20 ee 0.01 Colloid. Pt E 2 8.0 $108 ots vee i OR OR i Aaa essa t Eg t eb oe ee O60 6 oe. E, Eg 1,1 Pe Pelee cera e aa 0.02 AuCl,, 100.0 Eg I 20h. eee 0.01 0. Eg, Gp yf PA eel ces 0.02 Colloid. Pt, E : 86.4 2b es 0.01 Colloid. Pt, E, E :* 4 OY Re geeeee oe, a 0.02 Colloid. Au, E, E 4,3 go.0 Ls lati a: le 4 was a portion ofthat employed it gage el - the colloidal gold solution; that used in siteaoes shes was prepared at another time- ga used in no. 24 was Oscillatoria from a 0.1 per cent Sachs’s solution, thickened with 1 Per cent agar. 1914] HOYT—COLLOIDAL METALS 199 second and third days many filaments were injured, while on the fourth day practically all were dead. Diluting the gold solution with an equal volume of non-toxic water produced no improvement. In such a solution Spirogyra from the stock culture remained in excellent condition one day, but on the second day about half of the filaments were dead (II, 5c). The effect of transferring portions of Spirogyra from colloidal gold solution to non-toxic distilled water was tested. Filaments which had been in gold solution for two days, when placed in this water, showed injury within one day and were, for the most part, dead within two days, while the portions of the alga remaining in the gold solution were still in excellent condition. Other effects of such transfers will be described later. 7 Although the colloidal gold solution itself was only slightly injurious, the sodium hydrate solution (about 0.02 per cent) used in its preparation was extremely toxic, killing all the filaments and causing contraction of their cell contents within 17 hours (II, 6). This alkaline water, when diluted with an equal volume of non- toxic distilled water, was still decidedly toxic (II, 7), but was not injurious during the period of the experiment (5 days) when diluted with an equal volume of the full strength colloidal platinum solution (II, 8). A similar improvement by the addition of colloidal platinum was produced on 0.02 per cent and 0.01 per cent solutions of NaOH prepared at another time (II, 10, 12). Even weak solutions of silver seemed to produce a beneficial effect on this alkaline solution, since the alga lived better with the addition of ®-0I-9.005 per cent of the full strength silver solution (0.009- °-0045 ppm.) than in the NaOH solution alone (II, 9). The addition, however, of 0.01 per cent of AuCl, to 0.02 per cent and 0.01 Per cent solutions of NaOH produced no improvement in these solutions; on the contrary, the soluble gold salt seemed to make the NaOH solutions more injurious (II, 10, 11). The colloidal solution of platinum was still less injurious than that of gold, filaments of S pirogyra placed in this solution remaining apparently perfect condition for g days and dying only after 22 days (IIL, 13). Not only was this platinum solution not injurious during the first few days of the experiments, but it produced 200 BOTANICAL GAZETTE [MARCH improvement in a o.1 per cent solution of KCI (III, 14), in a 0.02 per cent solution of MgSO, (III, 15), and in a mixture with an equal volume of tap water or an equal volume of ordinary distilled water (IIT, 16), over such solutions without the colloidal platinum. It also, as has been shown above, produced improvement in a weak colloidal solution of silver and in a solution of NaOH. The addi- tion, however, of 0.008 per cent PtCl, to a 0.02 per cent solution of MgSO, produced no improvement in this solution (III, 17). A few experiments were made with other algae. Spirogyra decimina Kg.,3 newly brought to the laboratory, gave practically the same results as those already described, except that it was more quickly injured by colloidal gold solution (IV, 18-23). However, filaments of a species of Oscillatoria growing in o. 5 per cent Sachs’s solution thickened with 1 per cent agar, when transferred to the gold solution remained in pet- fect condition and continued their usual movements during . Spirogyra longata from the period of the experiment eal creat shoei after rane = ( 3-4 days) (IV, 24). : mike When filaments of Spirogyré longata from the stock culture or filaments of S. decimina were placed in colloidal gold solution, @ striking phenomenon was observed; the outer layer of the cell walls swelled irregularly within 17 hours, forming gelatinous sheaths over considerable portions of the external surfaces (fig. 1). These sheaths, whether greatly swollen or not, were colored purple by the ' gold solution. The cells remained in otherwise excellent condition during this time; their contents were uncontracted and normal in appearance, and the chloroplasts retained their usual green color. That the cells were alive and healthy was indicated by the fact that they were easily plasmolyzed by glycerine. When filaments of S. longata were examined directly in the gold solution, they showed slight irregular swellings (fig. 1), but when transferred from the gold solution to glycerine solution or to non-toxic distilled watet marked swelling became evident over the entire wall within one OF Siiss- 3 Determined from O. KrrcHNer, Die mikroskopische Pflanzenwelt des wassers. 1885. 1gr4] HOYT—COLLOIDAL METALS 201 two minutes (figs. 2, 3). Under the latter conditions the modified outer layer frequently became ruptured, breaking away from the wall in purple, gelatinous masses and leaving the remainder of the wall and the other portions of the cell uncolored and apparently unaffected. Filaments of S. decimina formed swollen sheaths in the gold solution itself similar to those formed by S. longata when transferred from this solution to water. After a top “age Fic. 2 Fic. 3 Fics. 2 and 3-—Spirogyra longata from same material as that shown in fig. 1, 48 hours after transfer to colloidal gold solution; examined and drawn in distilled water. sheath had broken from a portion of the wall, no new sheath was formed, the rest of the wall remaining unswollen and uncolored during the period of the experiments (2-6 days). The results of further studies upon the formation of these gelatinous sheaths are Presented in table V. Where difficulty was experienced in deter- mining by simple microscopic observation whether or not swelling of the outer wall had occurred, such difficulty was removed by treatment of the material with Bismarck brown, which so stains TIAA A AT o render ture (72 days old) in o.1 per cent Crone’s €ven very thin sheath layers solution, 48 hours after transfer to col- Clearly discernible. loidal gold solution; examined and drawn Sheaths were formed in the apogee dees gold solution by Spirogyra longata from the stock culture (V, 14), and by S. decimina (V, 1c), and they were produced to a very slight degree by a species of Oscillatoria (V, 1d). No sheaths were thus formed upon filaments of S. longata (fig. 4) which had been for 72 days in o.1 per cent Crone’s solution (V, 10), nor by a species of Hormidium (V, re). Sheaths failed to appear upon S. longata in colloidal gold solution diluted with an equal Volume of non-toxic water (V, 2), nor were they evident upon BOTANICAL GAZETTE TABLE V VARIOUS TREATMENTS PRODUCING EXTERNAL SHEATHS ON ALGA CELLS, TOGETHER COMPARATIVE TREATMENTS FAILING TO PRODUCE SUCH SHEATHS [MARCH MEDIUM EMPLOYED, NON-TOXIC UMBER OF TESTS IN 3 DISTILLED WATER CONTAINING WHICH SHEATHS WERE Zz 2 ALGA EMPLOYED Suspe nsoids and ‘Solutes and Notes* ir XI. \- a mate comeentra mate concentra-| Formed | Not formed iS) » Pp tion, p.c. 1a | Spirogyra Gold, 90.0 | NaOH, ee te eee E; sheaths formed longatat o.o2t within 17 hours 1b | Do., from do. OO ie te 2 culture in 0.1 p.c. Crone’s sol. 7 days ol : 1c | Spirogyra do. do. Pelee fe ae oe ; within 4 decimina§ Sheaths fo’ within 17 hours 1d | Oscillatoria\| do. do. 1 (?) I E; a few filaments in one culture showed | slight sheaths when transferred to p water; no sheaths appar ent in gold so- lution. Usual movements ob- te | Hormidium do. Ai le es Pon Ss ee a et 2 ] is0mt, 40.01 N@OM. 13. & 2 ek ee es ae ee ongata 0.01 96 De a a a Awl, 6.612. 65: 2 D; many filaments INaOQH, 0.029 30 | S. dectaina toe gee I G 4a | S: foams lo Ri Ol... 2 G Nai 0.01 4b. 1 Sleiman {2 FETS Sa i Uae 2 G §- ) Sitoag@a TS pe a, ee I D 0.02t 68) | D8. es Oe NAO oe. I D 0.01 6b | S. decimina |............ vg ak Cea ae No — eae i Renee colorless ones appea n second day, when rags mostly 76 | S. lonpaig 1 MeOH be says 2 G, in one culture 0.029 sod 7b | S.decimina |............ "ae ee I D S Jongate og as Nat eta ae 2 G °.o1§ 1914] HOYT—COLLOIDAL METALS 203 TABLE V—Continued MeEpiIum EMPLOYED, NON-TOXI ER OF TESTS IN s DISTILLED WATER sAaaaibatr WHICH SHEATHS WERE Z a ALGA EMPLOYED pore nsoids and —— and Notes? : mate concentra mate concentra-| Formed | Not formed Oo n, pp i 8) | S.decimina |............ NaOH; oor 9) 2-2 2 9 | S.longata Pinte po Se eh ere I E, for 9 days 96.0 D, after 22 days 1o | Do. Platinum, dap water, [0.5.8 I G : 48.0 50.0 11a | De, do. 2 Pammaians Seca Sh I E o.o1f 11) | S. decimina do. do. y Hertaey Giger e E; cenig sheaths within 17 hours, colored ge 12a | S. longata Platinum, NaOH, I I G; fs slight 86 4 0.029 shea ths in one ure 12b | S. decimina do. do. oo ea E; heavy sheaths within 17 hours; colored by Pt. 130 | S. longata do. WeOH, 2 E P o.o1f 136 | S. decimina do. do. Sap aoe es a E heavy sheaths within 17 hours, colored by Pt. peep e eeeee | Silver, oo, |..... |... 2c... 19 Mostly D, in some and. vari- cases G a lower concentra ions 15a | Do mrver,@.940) NAOH, |. 53.25). I D 0.02 ‘ 15b | Do. ilver, 0.09 = ges ula tos I Mostly D og Do. Silver, 0.045 oes Rages I Gp 10 | Do ON a a 5 E 96.0; sil- ver, vari- ous con- tra- tions be- OW 90.0 17 | Do. Silver, vari-| Saltstoform|......... 5 E ous con- Crone’s centra- solution, tions be- 0.5 low 90.0 All Sod firenra I eta slats Be Gel on ae ens pond trom aaa is The general Colisids and the ultramicroscope. Trans. by J. Alexander. New York. 1909. THE FUNCTION OF MANGANESE IN PLANTS W. PP, Kertiry Historical introduction Dating from the time of ScHEELE (1), numerous investigators have noted the presence of manganese in plants of various orders. While small amounts only of this element have been found in most plants, in 1860 Hizcarp (2) pointed out that the ash of the long- leaf pine from Mississippi contains a relatively high percentage; and in 1878 J. ScHROEDER (3) found in the ash of the Norway spruce (Picea excelsa) 35.53 per cent Mn,O,, and in the ash of the bark 41.23 per cent. These and other observations, however, received but little attention for many years. Manganese occurs in small amounts in practically all soils, but being an element unessential to growth and normal development, its absorption by Plants was considered to be without physiological significance. The discovery of BERTRAND (4) in 1897 of the occurrence of Manganese in the oxidizing enzymes of plants, however, and the Subsequent finding that small amounts of manganese salts stimu- late the oxygen-carrying power of these catalytic agents, have drawn attention to this question and have led to the view that after all a physiological réle is probably played by this element. Since the time of these discoveries a large number of experiments, with 4 wide range ‘of plants, have been made, various compounds of Manganese in water and soil cultures being used; and, in general, it has been found that small amounts of manganese bring about stimulation in growth. While small amounts often produce stimu- ation, wherever more than a very low concentration has been employed, toxicity has resulted. Loew (5) and his co-workers in Japan found, furthermore, the toxic concentration in water cultures to be different for different *Pecies of plants. A concentration that was stimulating to rice, for mstance, proved to be toxic to barley. Likewise, SALOMONE (6) observed in field experiments that the application of such small amounts as 40 kilograms per hectar of manganous sulphate pro- 213] [Botanical Gazette, vol. 57 214 BOTANICAL GAZETTE [MARCH duced injurious effects on wheat, while other investigators have found stimulation to result from the application of much larger amounts. In a number of instances, however, the application of different amounts of manganese in field culture has produced no apparent effects. Regarding the specific effects produced by manganese, BERTRAND, as stated above, and a number of other investigators, have shown that, on the one hand, the addition of small amounts of soluble manganese increases the oxygen-carrying power of the oxidases, and on the other, stimulation is produced in the oxi- _dizing power of infusions from plants grown under the influence of manganese compounds. During recent years an increasing impor- tance has been attached to the oxidizing conditions of the soil, and, as has been pointed out in the researches of SULLIVAN and REID (7); there appears to be a direct correlation between the growth of plants (fertility of the soil) and the oxidations going on in the soil. The catalytic oxidations in soils have also been found to be pro- portional, within certain limits, to the percentage of manganese contained therein, and to be susceptible of stimulation by the addition of manganese compounds in much the same way 45 stimulation in the activity of plant oxidases is produced by the application of manganese salts. Certain other investigators have also studied the effects on the solubility of plant nutrient constituents of soils produced by the application of manganese compounds. BeRNARDINI (8), [oF example, has shown that manganous chlorid causes a mobilization of calcium and magnesium from both soils and mineral silicates t a greater degree than is produced by potassium, sodium, or ammo nium chlorides.! | From these facts the conclusion has been draw? that plant stimulation, resulting from the application of nical ganese compounds, is probably due to indirect effects on the inert bases of soils. As bearing on this phase of the question, ASO (9) also pointed out that while a 41.8 per cent increase in the yield of rice was obtained from the first application of manganous sulphate, similar applications to the same soil the following year produced only a 2.2 per cent increase. t See Nortin, Ann. Sc. Agron. Ser 4. pp. 1-12. 1913. 1914] KELLEY—FUNCTION OF MANGANESE 215 The toxic effect above mentioned usually manifests itself by a dying-back of the growing tips and the yellowing of the leaves. Loew and Sawa (5) hold that the activity of the oxidizing enzymes of plants may become excessive under the influence of sufficiently great amounts of manganese, resulting in the auto-oxidation of the chloroplastids, thus destroying the green pigment. SALOMONE (10), on the other hand, found evidences of plasmolysis in wheat that had been fertilized with manganese dioxide at the rate of fifty kilograms per hectar. BRENCHLEY (11) also observed a_ toxic action from manganous sulphate when it was applied in the very low concentration of one part per one hundred thousand parts of culture solutions. When it is remembered, however, that many plants vegetate normally in culture solutions varying rather widely in ionic-concentration, without showing evidences of plasmolysis, in other words, the ionic-concentration of the cell sap considerably exceeds that of ordinary culture solutions, it seems improbable that the addition of such small amounts of manganous sulphate would produce plasmolysis as a direct effect. From the foregoing brief résumé? of the experiments on this question, it will be seen that two different sets of views have been held by which the action of manganese on soils and plants has been explained. These may be briefly stated as follows: (1) man- §anese stimulates the necessary oxidations going on in soils and plants through the activation of the oxidizing enzymes, etc.; (2) the application of soluble manganese brings about plant stimu- lation by rendering soluble, and therefore making available, the essential plant food of soils. Under the first named of these theories may be included the stimulated oxidations, in both soils and plant tissues, the former Probably being referable to the action on certain microorganisms, as well as on soil catalysis, while the latter has to do with the physio- logical processes within the cell. Viewed in the light of the last named theory, the effects of manganese on plants are considered to be indirect and due to its increasing the solubility of the mineral Constituents of soils. ae more complete bibliography of literature dealing with this subject will be n @ paper by the writer published as Bulletin 26, Hawaii Experiment Station. 216 BOTANICAL GAZETTE [MARCH A study of the literature on this subject, embracing as it does experiments with a considerable range of plants, reveals discrep- ancies, and, in the opinion of the writer, casts doubt on the adequacy of either one or both of the above mentioned conceptions as fur- nishing sufficient basis for a complete explanation of the function of manganese in plants. In this connection, the application of the principles of plant physiology, particularly osmosis in its bearing on the absorption of chemical substances from soils, naturally raises the question of the influence of soluble manganese on the selective absorption of the necessary nutrient elements. SCHREINER and SKINNER (12) have shown, for example, that small amounts of cumarin materially alter the absorption of potash by wheat seedlings; that quinone modifies the osmotic absorption of phosphoric acid; and that vanillin and dihydroxystearic acid exert a noteworthy influence upon the absorption of nitrates. Up to the present time the fundamental steps and the specifics of these reactions have not been elucidated. The exact “how” as yet can only be inferred. With regard to the specific effects on the osmotic phenomenon produced by small amounts of inorganic elements occurring in soils, other than the so-called plant food elements, little indeed is known. It is reasonable to suppose, a priori, that some osmotic effect would be produced. In fact, it seems improbable that the presence of any considerable amount of an electrolyte in the nutrient solution would exert a strictly neutral effect. For a number of years the writer has studied the effect of man- ganese on plants. A preliminary report of this work was publish in 1908 (13), in which it was shown that certain soils of Oahu, used for pineapples, contain abnormally high percentages of manganese. n these areas the pineapple undergoes the phenomenon of chloro- sis, the leaves becoming yellow and the fruit pink in color through- out the entire period of its growth. The growth of the plant stunted and the fruit produced is inferior in size. Further invest gation of this question has led to a study of the function of man- ganese in plants in general, the results of which, in view of the prominence of the question, appear to be of sufficient interest to warrant a brief discussion at this time. 1914] KELLEY—FUNCTION OF MANGANESE 217 Experimental observations The macroscopic appearance of a number of plants when grown on manganiferous soil is characteristic. Pineapples develop chlorosis at an early age, from which they never recover. The effects are first noticeable by a yellowing on the margins of the leaves or the development of yellow spots which soon spread over the entire leaf. The growing tips die back, the leaf margins becoming brown. Usually such plants produce small fruit of an abnormally pink color. Pineapple roots, instead of maintaining the usual pointed growing tip, are often found to be greatly enlarged, sometimes to the size of a lead pencil. The roots of other plants also become modified to some extent. Those of Panicum molle are found to be abnormally woody. Others are similarly affected. Corn makes poor growth, the leaves turning brown at an early Stage and the stalks taking on a deep purple color. Barley, oats, and rice are likewise stunted in growth. Of the Leguminosae, the cowpea (Vigna catjang), in particular, is very sensitive to man- anese; the lower leaves become brown, die back from the tips, and fallaway. The pigeon pea (Cajanus indicus) is affected some- what similarly. Onions also die back from the tips and produce very small bulbs. Some species, however, appear not to be affected. The Agave sisalana shows no effects; sugar cane is not greatly affected, and cotton and tobacco, although somewhat retarded in growth, are hot otherwise affected. Waltheria americana, the sow thistle, and @ species of Crotalaria grow as weeds on the manganiferous soils and are in no way hindered in their development. These illus- trations could be greatly enlarged, but are sufficient to indicate that the apparent effects of manganese in different species are far from being uniform. Microscopicat stupirs.—From a microscopical study of the Several parts of these plants, it was found that in those instances where manganese exerts a toxic effect, the cell walls of the root cortex become brown, and in some instances contain minute gran- ules of manganese dioxide. In a few instances the cells having brown cell walls extend into the central cylinder of the root, and 218 BOTANICAL GAZETTE [MARCH it is not uncommon to find a thickened tissue lying next to the cell walls in the angles of the cells. In the more advanced stages of chlorosis the protoplasmic contents of pineapple leaves become contracted into formless masses and appear to undergo partial decomposition. Normally, the palisade cells (14) of this species contain not more than mere traces of chlorophyll, being essentially water-storage tissue. Under the influence of manganese the liquid content becomes coagulated and draws away from the cell walls; likewise the protoplasm in the chlorophyll-bearing cells breaks away from the cell walls in places, contracting into an irregularly shaped mass. Plasmolysis, therefore, takes place, and in a few instances the nuclei become brown. At the beginning of the chlorosis there is a fading of the green color without any other noticeable change; but in successive stages the chloroplastids gradually become fewer in number and smaller in size until finally they almost completely disappear. Simul- taneously with the fading of the chlorophyll, a diminution in the starch contents takes place, and as the chlorosis develops, less and less starch is found adhering to the chloroplastids, until finally it entirely disappears. In the chlorotic plants the palisade cells also seem to be given over to the storage of calcium oxalate, and the occurrence of this metabolic by-product is greatly increased in practically all parts of such plants. OXIDIZING ENZYMES.—The view that manganese exerts an influence on plants, through stimulating the auto-oxidations (so indispensable to living matter), gives interest to a study of the oxidizing enzymes occurring in plants from manganiferous soils. Accordingly, the oxidase and peroxidase activities of infusions obtained by crushing the leaves were measured empirically by = of the guiacum and aloin reactions. The results showed that while infusions from some chlorotic plants contain vigorous oxidizing enzymes, frequently such infusions give much weaker oxidase and peroxidase reactions than normal plants. These tests have been applied to infusions from all parts of pineapple plants, coming from soils containing manganese in amounts varying from 0.o1 to 9- 75 per cent, and with plants at all ages and in the various stages in the development of chlorosis; but when applied to a large series of 1914] KELLEY—FUNCTION OF MANGANESE 219 samples no correlation was found between the percentage of man- ganese in the soil or the degree of chlorosis on the one hand, and the activity of the oxidizing enzymes on the other. These tests have also been made with various other plants, some of which show toxic effects from the manganese, and with still others that appear not to be affected. On the whole, the results again fail to show any relation between the activity of the oxidizing enzymes and the percentage of manganese in the soil, or the toxic effects. As is well known, the activity of oxidizing enzymes in different specimens of a given species of plant is by no means uniform when grown on normal soils. It has been found, for instance, that extracts obtained from the fresh leaves of normal sugar cane and pineapples, respectively, varied in their oxygen-carrying power between wide extremes. It is also known that pathological dis- turbances, caused by attacks of Aphidae, the mosaic disease of tobacco, etc., are also associated with accelerated oxidation. The autumnal yellowing of plants, incident to maturity, and the devel- opment of yellow spots on certain plants, have likewise been shown by Woops (15) to be associated with an increased activity of the oxidases and peroxidases. It seems reasonable to suppose, therefore, that while man- §anese has the power of increasing the oxygen-carrying power of oxidases, and consequently may, in this way, to some degree bring about plant stimulation, the phenomenon of chlorosis cannot be - completely explained on the basis of excessive auto-oxidation. qT development of chlorosis under the influence of manganese 'S very probably the result of physiological disturbances of a more deep-seated nature. Composition or THE AsH.—A number of ash analyses have been made for the purpose of determining the effects of manganese on the absolute, as well as the relative, absorption of plant food elements. The materials for analysis were selected with the Sreatest care, so as to secure representative plants of the same age and stage of development in a given species. The results are Tecorded in table I. The data given in table I bring out some interesting facts. In 220 BOTANICAL GAZETTE TABLE I [MARCH ASH ANALYSIS OF PLANTS GROWN ON NORMAL AND MANGANIFEROUS SOILS i horic Plants analyzed eon] cts, | Magnetie |Ebaspns 5) Total aah Pineapple leaves 5 months old: Pt, Pct Peck fa. P at. Man ae enous $0lb 3c 2. ns a. 2.41 9.01 5.70 2.81 9.94 INOLENAL AOL foe Se cS 1.70 EA 7.60 287 7-14 Rivapele ‘ean 18 months old: 8 oot ae SOR oe ae ode On hae OG 7.91 1.66 7.98 ERIGEBOMS cesses a eg kG 1.40 7.00 6.98 2.70 6.24 Pineapple stalk 5 months old: Manganiferous soil............. ; as 2130.42 2.60 6.12 8.85 POOR a A Se as Ry 5.82 8.86 5.12 Pineapple stalk 2 years old: Manganiferous SONS ye eee .80 | 14.36 7.76 6.70 7.78 Norm aye He cee ee ee .20 | 12.96 5.78 8.36 6.60 Corn sto iacsanitetiu: SOc es oe .40 8.60 7.64 5x17 7-55 Norm oe = Lepage ee oe ae oe 3.45 4.60 7.56 18 Cowpea v fy als ae SS ea S507, cf 22292 6.93 2.90 | 13-73 No! rmal soil Re eee ae Cea nee Ot 1-39-50 9-13 5-03 3-44 Cowpeas Mkneia items SOs Gas ee 15 1.47 4.15 | 15.89 3-93 INGUINAL SOU goa se .00 Tt. 13 6.91 227k 3-53 gyi eae orbiculare: erode Well. 5 cL a 26 5.30 3.46 2.54 7-88 a. ee Sa eee es ep 1.05 6.70 5.05 2.34 7.16 Guava lea a ne BORD Soo Smee .82 | 43.02 73 4.47 7.66 PIGPIONY WE. eo ee .28 | 22.98 | 10.46 7-79 6.73 Guava wood: Manganiferous a. ee 1.20 | 52.10 2 er 4.33 5-87 Nownll abss 55 ot ac -15 | 26.17 7.22 6.97 | eet Steao-cane leaves: Man: Bide Pari Mas i at .33 4.4 |0 5.28 5-37 No rmal le i 60 | 16.60 | 6:07 | 4.03 | 4-85 Crotalari Manganiferous ns (Ry es Sie eg 1.40 | 30.80 7-79 4.12 6.77 Normal #8106... oe sOn <1 16.60°.| 21-05 9-13 6.28 Peanut at kes Manganiferous 08 (ae) 38 ae 5.61 4.49 | 10-45 Normal qoib. fcc. jeer .04 | 39.41 | 10.99 4.97 9-95 Peanut eee Matehattasis BOC. 2.56 | 14.80 9.04 2.00 | 11-15 Normal soll. 26 i .32 | 21.76 | 19.02 4.81 = ali (Casuarina equisetifolia) Manganiferous ee .66 | 37.50 4.57 4.03 feet: ormal sowiiicsc eee eg ‘ES Po 7.95 48S ee Olive leaves: : Manganiferous soil............. .64 | 26.32 1.84 2,03) poet Normal Gi 86: }.47.Bo | 1.83 | 2.78 Ge Waltheria americana leaves: Manganiferous soil............. 8.70 | 31.30 3.81 2,50 fart Notmalsol 3.0.6 a .82 | 29.62 5-44 abo be Bie element 1914] KELLEY—FUNCTION OF MANGANESE Zot TABLE I—Continued Plants analyzed oo ‘camn hor ee Po Total ash Waltheria americana stems: Manganiferous soil............. .56 14.97 11.70 3-67 3.58 0 | SB eee 45 13.70. | 15.56 3.46 373 Broom-corn leaves: Manganiferous soil............. 2.24. | 12.08 6.75 Be hier ee te .60 5-44 3.52 st al Merge ge Broom-corn stalks: Manganiferous soil............. 1.36 4.43 3.12 $02 Voce. I 52 1.88 2.51 3-72 |--e eee Tobacco stems: Manganiferous soil............. ao 9.47 4.08 2.08 7.02 Dee T. 1.68 | 3.27.) 7-38 | 8.50 Pigeon-pea leaves: Manganiferous soil............. ¥.43 16.11 32.25 4.04 | 12.17 ee 7.86 7.66 | 10.85 84 Pigeon-pea stems Manganiferous soil............. .99 | 15.29 2.82 4.25 5.81 ree co 3.79 4.390 | 0.34.) 6.2 Oat straw: Manganiferous soil............. .86 9.15 5.16 -73 | 10.27 ES See ae Ee 3.40 5.10 8.81 11.73 Wheat straw: Manganiferous soil............. 22 4.51 4.03 2.96 8.91 ES ee ees i 2.09 ie 5.56 16.27 Mango leaves: Manganiferous soil............. 2.10} 44.49 2°15 2.89 9.24 ee a ew ae 4.90 5-43 8.21 practically every instance the ak sorption of manganese was increased on the manganese soil. The analyses further show that there is a Pronounced difference in the percentages of lime, magnesia, and Phosphoric acid in the ash of plants from the two classes of soils. Some of the plants were not visibly affected; others little so; while still others showed a pronounced toxic effect; but uniformly Aroughout there was a tendency toward an increased absorption of € on the one hand, and a decreased absorption of magnesia and Phosphoric acid on the other. Under certain conditions the ratio of lime to magnesia seems to be of considerable importance to plants. In order to bring out more clearly the relations between these two constituents of the ash, the relative amounts of lime and magnesia absorbed from normal and manganiferous soils, respectively, have been recal- culated from the previous ash analyses and are presented in table II. An inspection of the data in table II shows that in almost every 222 BOTANICAL GAZETTE [MARCH TABLE II THE RATIO OF LIME TO MAGNESIA IN PLANTS (MAGNESIA CONSIDERED AS 1) TO To From Kind of plant beni bao Kind of plant Tifetous | normal soil soil soil soil Pineapple leaves: Ironwood needles....| 8.20 5.56 5 months old..... 1.58 04 Olive leaves........ 14.30 | E103 ths old. . 1.98 1.00 altheria americana Pineapple stalk: Paves sob ase 8.21 5.44 ins O10... £5. 14.00 4.10 tes esas 1:28 1/2 18 months old..... 88 2.24 Broom corn Com StOVER Soe. 1.12 Se LOAVES eo a 1.79 1.54 Cowpeas oli a 1 Rene een Ee .67 -74 WINGS 0 3.28 1.86 Tobacco stems...... Oe 57 as Neg gsare arene 35 16 Pigeon peas: Paspalum orbiculare..) 1.53 ¥.32 ee Ee ee 4.69 1.02 uava: terme 42 86 ee ee eee 11.53 To FES Ee SPR 1.79 1.07 mies Suntan 34.50 3.62 Wheat straw... ....| 5-42 .76 Sugar cane leaves ....| 3.25 2.94 Mango leaves....... 15.40 3-49 Crotalaria (205.0555 3-95 go Peanut: Leaves 6552.3: 6.28 3.58 te Ca 1.63 1.14 instance the ratio of the absorbed lime to absorbed magnesia was increased under the influence of manganese. Discussion In this investigation it has been shown that different plants, when grown on manganiferous soils, are affected differently. Some species are stunted in growth and die back from the tips of the leaves, which turn yellow or brown, and sometimes fall off, and a general unhealthy appearance results. Other species appear to be unaffected, and, so far as can be judged, vegetate normally in the presence of manganese. Microscopic investigations show that in certain instances the protoplasm undergoes changes. Occa- sionally it draws away from the cell walls and the nuclei become brown. There is a manifest change in the protoplasmic contents of the roots. The chlorophyll in a number of plants is affected; in pineapples it undergoes decomposition. Simultaneous with the destruction of chlorophyll, starch formation ceases. The activity of the oxidizing enzymes in plants is herein shown to bear no relation to the destruction of chlorophyll under the 1914] KELLEY—FUNCTION OF MANGANESE 272 influence of excessive manganese. While the oxidases generally contain manganese as a normal constituent, or at least manganese is closely associated with the oxidases, and at the same time their oxygen-carrying power is accelerated by the presence of man- ganese salts, the foregoing investigations show that there is no correlation between the phenomenon of chlorosis in pineapples and the activity of the oxidizing enzymes. The decomposition of chlorophyll in this case, therefore, is not due to excessive auto- oxidation. This does not imply, however, that accelerated auto- oxidation in plants is without effect. From the ash analyses it was found that manganese was absorbed in considerable quantities, and in nearly every instance was greater in the plants from manganiferous soil. These analyses also show that a disturbance in the mineral balance takes place. The percentage of lime is increased, while the percentage of mag- nesia and phosphoric acid is decreased. Some of the plants ana- lyzed showed a markedly toxic effect from the manganese, while others appeared to be unaffected; but in practically every instance a modification of the mineral balance was observed, and this was found to follow the same direction in all species. The ratio of absorbed lime to the absorbed magnesia was increased under the influence of manganese, regardless of whether the plant showed a toxic effect or not. It is claimed by Loew (16) and others that various plants are affected differently by different ratios of lime to magnesia; certain species of plants vegetate most advantageously when the ratio is one to one; whereas still other species grow best when the ratio 's one to three, etc. In the publications dealing with this subject, however, mention is usually made of the effects produced upon the appearance of plants, while but few ash analyses have been made 'n this connection. From the data at hand, however, it appears that where the physiological balance between lime and magnesia Is disturbed, a corresponding influence is brought about in the com- Position of the ash. Under the influence of manganese, plants automatically modify themselves in regard to the absorption of these two elements, and, 4S 1s believed, it is not so much the absolute amount of calcium and 224 BOTANICAL GAZETTE [MARCH magnesium in a given soil as the ratio between these two substances in solution in the soil moisture that determines the physiological effects. In the case of plants grown on manganiferous soil, the relative amounts of lime and magnesia actually absorbed become greatly different from those absorbed from normal soils, regardless of the amounts of these elements present in the soil. From these evidences, we may believe, then, that an important effect of manganese is of an indirect nature, being due to its bringing about a modification in the osmotic absorption of lime and magnesia, and that the toxic effects are chiefly brought about by this modifi- cation, rather than as a direct effect of the manganese itself. As has been mentioned already, not all species of plants are equally sensitive to modifications in the lime-magnesia ratio; and from some recent experiments of GiLE (17) it seems that the effects of a modification in this ratio are, to some extent, dependent upon the concentration of the culture solution. Likewise, different ratios are best suited to different species. Therefore, the effect of man- ganese may be very different on different soils and with different species of plants. With certain plants it is toxic on certain soils for the reason that the absorbed lime and magnesia are thrown out of their optimum ratio for this plant, while in others it may exert a stimulating effect by bringing this ratio more nearly to its optimum. The small amounts of manganese in natural soils, therefore, probably perform a twofold function in plant growth: (1) it acts catalytically, increasing the oxidations in the soil and acceler- ating the auto-oxidations in plants; and (2) it tends to modify the absorption of lime and magnesia, perhaps by partially replacing calcium from insoluble combinations, but especially, through . direct effect on the osmotic absorption of lime and magnesia, increasing the former and decreasing the latter. The absorption of phosphoric acid is likewise decreased in the presence of manganese. By reference to the preceding table of ash analyses it will be seen that frequently the ash of a given specie of plant from manganese soil was found to contain not more than one-half as much phosphoric acid as from normal soil. The intet- ference with the absorption of phosphoric acid would also tend to 1914] KELLEY—FUNCTION OF MANGANESE 225 bring about stunted growth and might be sufficient to account for the difference in size of the plants from the two classes of soil. Studies on the solubility of these soils have shown the manganese to be slightly soluble in water, but markedly so in dilute organic acids. Phosphoric acid coming into solution in the soil moisture would tend to be precipitated by the manganese as manganese phosphate, a compound, which can be dissolved only with diffi- culty, and therefore the absorption of phosphoric acid would thus be hindered. Reference has already been made to the fact that certain organic substances exert appreciable influence on the rates of absorption of certain of the necessary elements. Here it is shown that a similar action is to be ascribed to manganese. How is this fact to be explained ? During recent years the protective action of salts shown to obtain in animal experiments by Logs (18) has been found to apply also to plants. OsTERHOUT (19) has shown from water cultures, for instance, that some of the essential elements may be toxic unless properly balanced by definite concentrations of certain other necessary elements. In other words, some at least of the essential inorganic elements seem to play both a nutritive and a protective rdle. Quite recently OsTERHOUT (20) has been able to throw considerable fi t on the mechanics of the protective action. By the use of an Ingenious device he determined the electrical conductivity of living Protoplasm, both before and after it was placed in solutions of ium and calcium chlorides, etc. The results show that the electrical resistance of the protoplasm becomes greatly reduced upen standing in sodium chloride solution, thus indicating that sodium had been absorbed. But when the protoplasm was placed i a solution containing sodium and calcium chlorides, of the same lonic Concentration, no such lowering of the resistance took place. alcium hinders, then, the passage of sodium through living pro- toplasm; and therefore must be looked upon as lowering the per- meability. OsreRHout has further shown this phenomenon to be Teversible, and therefore the presence of one salt may actually Cause an increase in the permeability to others. In certain instances 226 BOTANICAL GAZETTE [MARCH he found the protoplasm to undergo visible changes, which, how- ever, were not necessarily injurious to it. Protoplasm, being of a colloidal nature, then, becomes physico-chemically altered when — placed in certain solutions; and such alterations, in turn, affect its permeability. By the application of the above named conceptions, we may infer that when plants are grown on manganese soils, the soluble manganese, coming into contact with the root hairs, is at first absorbed, up to a certain point, forming combinations with the protoplasm. Once these combinations are established, the per- meability of the protoplasm becomes altered, whereby the absorp- tion of lime is facilitated, while that of magnesium is hindered. Manganese, then, may be looked upon as forming a combination with the protoplasm which materially alters the relative absorp- tion of lime and magnesia. Not all plants are equally affected by a variation from the normal ratio of lime to magnesia, and there- fore under field conditions toxic effects may be produced in some plants, stimulation in others, while with still others the effects may be neutral. The experimental facts presented in this paper and the inter- pretations made in no way negative the work previously done on this subject. The failure to observe a more active catalytic oxt- dizing reaction in plants from highly manganiferous soil does not argue that manganese is incapable of stimulating the activity of oxidizing enzymes. The normal soils of Oahu, from which plants were taken for comparison, contain small amounts of manganese, which, moreover, was found to be absorbed to a considerable extent by all the plants studied. It is probable, therefore, that the absorp- tion of manganese from the normal soils of the Islands is sufficient to produce maximum stimulation in oxidase activity. Hawatt EXPERIMENT STATION ONOLULU LITERATURE CITED 1. SCHEELE, Kart W., Memoires de Chymie. Dijon. ee 2. HItGArRD, E. W., Renoct of Geol. and Agr., Miss. p. 360. 1 : 3- SCHROEDER, J., Untersuchen iiber Forstchem. und Palansenphysil Tharand. Forstl. Jahrb. Supp. 1:97. 1878. 1914] KELLEY—FUNCTION OF MANGANESE 227 4. BERTRAND, G., On the oxidizing action of manganese salts on - chemical composition of oxydases. Compt. Rend. 124:1355-1358. 5- Loew, O., and Sawa, S., On the action of manganese ae on plants. Coll. Ap. Imp. Univ. Tokio o, Bull. 5:161-172. 1902. SALOMONE, G., Il manganese e lo et delle piante. Staz. Sper. Agr. Ital. 38: 1015-1024. 1905. SULLIVAN, M. X., and Rem, F. R., Studies in soil catalysis. U.S.D.A., Bur. of Soils, Bull. 86. 1912. 8. BERNARDINI, L., Funzione del manganese nella concimazione. Staz. Sper. Agr. Ital. 43:217-240. 1910 9. Aso, K., On the stimulating action of sere chlorid on rice. Coll. Agr Nei Univ. Tokio, Bull. 7:449-453. 10. SALOMONE, G., Il manganese e lo ees pier piante. Staz. Sper. Agr. Ital. 40: “seca 1907. 11. BRENCHLEY, W. E., The influence of copper sulphate and manganese sulphate upon the growth of barley. Ann. Botany 24:571-583. 1910. 12, SCHREINER, O., and SKINNER, J. J., — compounds and fertilizer action. USDA. Bur. of Soils, Bull. 77. 19 13. KELLEY, W. P., The influence of manganese on a growth of pineapples. USD.A., Hawaii Sta. Press Bull. 23. 1909. : 14. Witcox, E. V., and KELLEY, W. P., The es [ manganese on pine- apple plaute: U.S.D.A., Hawaii Sta. ‘Bull. 28. oops, A. F., The destruction of ey ‘< oxidizing enzymes. Centralbl. Bakt. u. Par. 5:745-754. 1899 » Loew, O., and May, D. W., The polation of lime and magnesia to plant growth. USDA. Bur. Plant Ind., Bull. 1. 1901; Aso, K., Joc. cit., On the influence of diderent ratios of es and magnesia upon the development of plants. Coll. Agr. Imp. Univ. Tokio, Bull. 4:360-370. 1900-1902; 5*495-499. 1903; 6:97-102. 1904-1905; LoEw, O., and Aso, K., 7:397- 497. I90 17. GILE, PL L., Lime-magnesia ratio as influenced by concentration. U.S.D.A., Porto Rico Sta. Bull. 12. 1912. 18. Logs, J., Dynamics of living matter. New York. 1906. 19. OsterHour , W. J. V., On the importance of physiologically balanced solu- tions for Seer Bor. GAZ. 42:127-134. 1906; 44:249-272. 1907; the Similarity in the behavior of sodium and potassium. ce Gaz. 48:98- 104. I9g09 20. ———— The permeability of protoplasm to ions and the theory of antago- nism. Science N.S, 35:156-157. 1912; Changes in permeability produced by electrolytes. Science 36:350-352. 1912. > ma Lal uw . al an THE DEVELOPMENT OF THE PROTHALLIUM OF CAMPTOSORUS RHIZOPHYLLUS tok ei Ck ET? (WITH PLATES XII AND XIII AND EIGHT TEXT FIGURES) In this region the spores of Camptosorus rhizophyllus mature from June to October. The long axis measures 18-24 u, and the shorter 12~20. They contain a few small oil globules, but are destitute of chlorophyll. The nucleus is inconspicuous in the living spore. The perinium is thick, dark, and shows many sharp, irregu- lar ridges with areas of unequal thickness intervening (figs. 47-55)- The exospore is seen with difficulty, if at all, as the perinium is very rarely pushed off when the spore germinates. The spores germinate slowly. The greater part of the writer's material was taken from fronds collected October 26, 1912, and kept between sheets of filter paper in a book in the laboratory. On November 22 the sporangia, after being scraped from the fronds, and crushed lightly to free the spores, were sown on well sterilized soil in clay saucers. The saucers of soil were protected from currents of air by bell-jars supported on small blocks of wood to allow proper ventilation, and were kept moist in a well lighted greenhouse at an average temperature a little above 70 F. The first sign of green was noted with a magnifier on December 17- On February 4, 1913, abundant antheridia were found on the larger prothallia, and one week later a few archegonia were found. On March 22 many old antheridia and archegonia could be found on the large prothallia. Other spores collected October 26, 1912, “were sown December 23, and kept under the same conditions aS the above, but out of direct sunlight. In these cultures the first sign of green was noted January 30, 1913. Other spores sown January 3 and kept in the light, where on days of bright sunshine the temperature reached 80° F. at midday, showed the first sign of green on January 30. In all these instances the prothallia wer composed of 3-10 cells before their color was noted on the soil. Spores sown on boiled tap water, and kept under the same conditions Botanical Gazette, vol. 57] [228 1914} PICKETT—PROTHALLIUM OF CAMPTOSORUS 229 as the above mentioned cultures, showed the beginning of germina- tion in 10-14 days. While spores collected in October germinated best before the first of February, a considerable percentage germi- nated as late as the last of March, having been kept in the dry air of the laboratory in the meantime. Spores collected from the usual habitat in March show a higher percentage of germination than those collected earlier and kept in the laboratory. Only a few mature; unopened sporangia may be found in the field as late as March, so but few spores can be secured at that time. All the spores sown at one time and under the same conditions do not germinate and develop uniformly into prothallia. A small bit of soil, bearing prothallia, taken from any one of the cultures mentioned above, would show, up to the first of May, widely different Stages of prothallial growth. Many times the writer has found on the same bit of soil the intermediate stages from prothallia composed of two or three cells to mature plants 2-3 mm. wide, and bearing antheridia and archegonia. That some of the small prothallia were dwarf male plants is beyond doubt, because of the Presence of antheridia. But that some of the spores were late in germination is clearly indicated by the constant recurrence of these gradations in development accompanied by a continual mcrease in the number of mature specimens. The plants from Which the photographs reproduced in pl. XIII were made were taken at one time from the same portion of one culture, and had exactly the same conditions for germination and growth. Germination of the spore When the spores are placed under the proper conditions for germination, they absorb water and increase in diameter from one- fourth toone-half. The swelling is followed bya rupture of the perin- tum and the exposure of the spore contents. The writer has been unable as yet to determine whether or not there are two distinct walls within the perinium. If present, they are quite transparent. ugh the opening in the perinium may be seen the oil globules, Sometimes an inconspicuous nucleus, and after a few hours a few Small chloroplasts. From this point two lines of development have been noted, 230 BOTANICAL GAZETTE [MARCH In the first case, as in the typical Leptosporangiatae, a small papilla is formed and cut off from the body cell by a wall. This papilla elongates to form the first rhizoid. It contains no chloro- plasts. Occasionally two such papillae are formed before the division of the prothallial cell (figs. 54, 55). Following the forma- tion of the first rhizoid, the body cell increases in size, the oil globules disappear, and the chloroplasts increase in size and number. The second division of the spore produces a new prothallial cell containing chloroplasts. ; In the second case, the first division may produce two prothallial cells similar in size, and both containing chloroplasts. The basal cell of such a group may later produce a rhizoid. From the examination of many germinating spores and young prothallia, it seems quite as common for the spore to undergo one or two divi- sions before the formation of a rhizoid as for the rhizoid to result from the first cell division. Numerous specimens similar to fig. 52; but without a rhizoid, have been seen. As germination proceeds, the perinium is distended but is not cast off; it may usually be found attached to the oldest cell of mature prothallia (figs. 14, 15)- As has been stated, immediately after the rupture of the walls, light green plastids appear in the exposed portion of the cell (figs. 51, 54). With the further growth of the spore and the formation of new cells, these chloroplasts become larger and increase rapidly in number. Throughout the life of the prothallium the chloro- plasts retain a distinct yellow tinge, imparting a characteristic color to the plant. They at all times show a quick reaction to intense light, crowding close to the vertical cell walls after a few minutes of brilliant illumination. The oil globules persist for a short time only, and may not be seen after the first division of the prothallial cell. Early development of the prothallia As was stated above, the first division of the cell may produce two similar cells, or may cut off a small cell which develops into 4 rhizoid. If the first division produces a rhizoid, the second division produces two cells similar in form and containing chloroplasts. Later divisions of the distal cell may occur in either a transvers® 1914] PICKETT—PROTHALLIUM OF CAMPTOSORUS 231 or longitudinal plane. In some instances consecutive transverse divisions occur until a long, protonema-like filament of many cells is formed (figs. 1, 2, 3, 61). The length of the filament may vary, but whether it be one cell or more than one cell in length, it finally produces, by longitudinal and further transverse divisions of its newer cells, a flat plate one cell in thickness. It should be noted that it is the rule for this plate to be formed by regular promiscuous divisions, without any suggestion of an apical cell or group, although exceptions may be found in unusually long filaments. Not infre- quently this plate is formed immediately after the first transverse division of the spore (figs. 4, 18). In other specimens the plate formation begins after a chain of two or more cells is evident (figs. 5, 6, 8, 10, 61, 63). Occasionally a prothallium shows that transverse divisions have been followed or accompanied by longi- tudinal divisions until a strand two cells wide and as long as the simple protonemal structure mentioned above has been formed (figs. 7, 11, 14). Fig. 13 shows an intermediate form where one cell of a single row has given rise to two by longitudinal division. More rarely a definite strand three cells in width is clearly shown (fig. 19). That these strands, one, two, or three cells in width, are hot a part of the regular prothallial plate is indicated by the abrupt beginning of the latter (figs. 5, 6, 7, 11, 14). Later growth of the prothallia The small prothallia increase in size by a promiscuous division of their cells in two planes. The location of growing regions and the direction of division of individual cells seem to follow no general rule. The resulting cell plates lack to a marked degree the regular- ity and symmetry usually found in the prothallia of related ferns. A glance at figs. 1-20 and at pl. XIII will give an idea of the many and various forms found. This continued promiscuous growth and division of the cells in the body of the prothallium is characteristic of Camptosorus rhizophyllus. In many cases prothallia of con- siderable size are formed by this growth alone before the formation of an apical region, as must have been true in those shown in figs. "319, and 59. This type of growth continues after the appearance __ Bes. 1-21 a.—Figs. 1-3, protonema-like prothallia, with possible beginning of apical growth at A in fig. 1, X120; fig. 4, small prothallium with mature antheridia, 48 1 Pe eas. ee a oe Se ee fi 6 X60; figs. 5 and 14, lly growth ps; . 6, 7, 8, and 10, examples of unsymmetrical forms, X120; fig. 13, longitudinal division of one protonemal cell, X 120; fig. 15, prothalli ith] late of cells f d before - * - o~ fF appearance of apical group, X40; fig. 19, prothallium with two growing points, %405 fig. 20, very small prothallium with mature antheridia, X120; fig. 214, antheridia borne on marginal outgrowths, 120; fig. 12a, group of antheridia from central part of fig. 12, X120; the other figures show various unsymmetrical arrangements of apical groups. ei 1914] PICKETT—PROTHALLIUM OF CAMPTOSORUS 233 of the apical region and even after the formation of the archegonial cushion or meristem. It is shown especially in the formation of various marginal outgrowths and in the plicate or crispate form of old prothallia. Such marginal structures, resulting from irregular Fics. 21-36.—Figs. 21-27, various marginal outgrowths; fig. 23, one-celled form Stowing directly from regular margin; see fig. 21@ for outgrowths bearing anther- a 8S. 28-36, various forms of apical cells and groups; fig. 36 is a of fig. 18 more ighly magnified; fig. 28, wholly lateral apical group, and fig. 31, apical group (@) de a sinus; all X 120 except small figures in figs. 28 and 29. cell multiplication having no connection with apical growth, are: also characteristic of Camptosorus. These marginal structures may be of one or of very few cells (figs. 6, 17, 56, 61), or may be of many cells and approach the dignity of lobes (figs. 7, 16, 58). The form of several such lobes is shown in figs. 21-27. The region of apical growth Although the prothallia may attain considerable size and even Mature gametes without the appearance of a typical V-form “pical cell or a distinct apical group, such a growing region is quite usual and typical. The appearance of the apical cell or group 1s 234 BOTANICAL GAZETTE [MARCH varied as to both time and position. In long, protonema-like struc- tures the beginning of a specialized growth region is usually indi- cated by the division of a cell once or twice removed from the distal end (fig. 1). In case a plate of cells has been formed as mentioned above, a group of cells anywhere about the periphery of this plate may become more active than the neighboring cells, and thus con- stitute an apical region or group. The formation of a distinct, individual, yo V-shaped apical cell has not been noted, although forms like figs. 8, 29, 30, and 32 suggest such. In the plant shown in fig. 8 the growing region would probably appear between a and rather than as a result of any activity of the cell at In many instances the apical region is quite sym- metrically placed (fig. 14); but an examination of figs. 7, 12, and 17 will show the extreme variation of position, and how far from symmetrical the placing of an apical group may be. Fig. 19 shows an even more interesting Case, of which a few have been found, where two such regions have been Fic. 37.—Large prothallium with distal margin almost plane as a result of activity of large apical group; X28 and 160. Fic. 38.—Portion of margin of large prothallium, showing almost continuous growing group; X160. formed. The very striking irregularity in the formation of the apical group is further shown in figs. 28-36 and in figs. 56 and 57: Fig. 28 with the group (a) entirely lateral to the evident axis of elongation, fig. 36 (an enlargement of a in fig. 18), and fig. 34 with the apical group beside a sinus are worthy of notice. Figs. 33, 34 1914] - PICKETT—PROTHALLIUM OF CAMPTOSORUS 235 and 35 show about as regular or symmetrical a formation as has been found. Another point to be noted is that as the prothallia grow older the apical group in- creases its activity, with the result that instead of being in a sinus of considerable depth it is pushed outward to form an almost straight mar- gin at that place (fig. 37). Closely related to this phenomenon are the Cases of proliferation now to be mentioned. Prothallia which have grown for four or five months, and those Fic. 39.—Old prothallium that has developed two special growing regions; X28 and 160. which have been allowed to become quite dry and recover, some- | Fic. 40.—S to those in in Hg. 39, but more fully develo and showing rhizoid; x 160. oe ‘oli ¥ sia Proliferations antheridia are forme pecial growing point similar times continue irregular _ growth at one or more points on the margin. Fig. 38 shows a part of the margin of a large prothallium with renewed growth, after desic- cation for several days. Fig. 39 shows two such regions on one prothallium. Fig. 40 shows an advanced develop- ment of such a region that has produced a rhizoid and might continue growth inde- pendent of the original pro- thallium. On some such d regularly and abundantly. The . Presence of archegonia has not yet been noted on them. 236 BOTANICAL GAZETTE : [MARCH Size of prothallia Prothallia bearing antheridia vary much in size at the time of maturing their first sperms. Examples of plants composed of but few cells and with mature antheridia (figs. 4, 20) are not uncommon; on the other hand, many reach a width of 1-2 mm. before producing their first antheridia. The dwarf antheridial plants never attain any great size; they are but one cell in thickness, and never pro- duce archegonia. Fig. 41 shows the prothallium in fig. 20 and another taken at the same time from the same part of a culture and drawn to the same scale. These were just maturing their first antheridia. Antheridia are quite evenly distributed over the lower surface of the older portions of the large prothallia, and over the lower surface and mar- gins of the dwarf forms (figs. 4, 12a, 20). Fig. 12a shows the abun- dance of antheridia on the large plant in fig. 12. Occasionally antheridia i rowths of Fic. 41.—Two prothallia of same age (as indi- ginal outg llia (6 cated by maturity of first antheridia) and from large pr othallia (ng. same bit of soil; x28. 21a). Five months old antheridia and archegonia, are sometimes 4 mm. wide. They are strictly dorsiventral, although they show a marked tendency to take an upright position. The margins are distinctly crisped and plicate. After six to eight months, the marginal growth of the plants continues and the older portions die away much as in the liverworts. The rhizoids develop regularly from the lower surface of the prothallia, and are most abundant on the central part of the older portions, that is, at the base of the plant. They are long, slender, and sparingly branched near their free ends. The photographs reproduced in pl. XIII give a general idea of their character. ihe only point worthy of note is that mentioned above in connection 1914] PICKETT—PROTHALLIUM OF CAMPTOSORUS 237 with the germination of the spore, namely, that the first division of the cell may produce a second prothallial cell instead of a rhizoid. Antheridia and archegonia The antheridia develop in much the same general way as described by Campsett' for Onoclea Struthiopteris as a type of the Leptosporangiatae. The stages in development are sug- gested in figs. 42-46. The one point worthy of mention is the formation of the neck cell. This cell is cut off by a division of the initial antheridial cell in a plane parallel to the prothallial surface, and is very regularly found, although sometimes the more orthodox development shown in fig. 44 is evident. The archegonial meristem is but little in evidence, being of small area and not conspicuous. It develops on prothallia soon aiter the appearance of the antheridia, and is found only on such plants as have a well formed apical group. Archegonia are found on plants 1.5mm. or more in width. Their development is in every way typical of the Leptosporangiatae, but only a few (4-8) are found on a prothallium. Summary The spores of Camptosorus rhizophyllus germinate very irregu- larly in point of time. Prothallia bearing antheridia only and those bearing both antheridia and archegonia are produced. Both antheridial and archegonial prothallia show a wide varia- Hon in size and form, the result of a promiscuous cell division and growt _ The formation of a typical V-shaped apical cell is rarely found, if at all, and the apical group is usually unsymmetrically placed. Old prothallia, bearing both antheridia and archegonia, may develop several marginal growing regions, and may even pro- duce proliferations capable of independent growth. The archegonia follow the typical Leptosporangiatae in their * Mosses and ferns, 1905, p. 315. 238 BOTANICAL GAZETTE [MARCH development. The antheridia usually form a neck cell before the regular antheridial divisions. INDIANA UNIVERSITY Bioomincton, Inp. - EXPLANATION OF PLATES XII AND XIII (Figs. 1-41 in text) PLATE XII All figures 660 Fics. 42-46.—Stages in development of antheridia; fig. 44 shows orthodox form sometimes found, the others show more usual form with a neck cell. Fic. 47.—Fresh, mature spore. Fic. 48.—Spore with cell showing through ruptured coats. Fic. 49.—Spore with rhizoid showing first. — IGS. 50, 51.—Rhizoids issuing from the ot exposed by the rupture of the coats: og, oil globules. IGS. 52, 53.—First and second divisions of the prothallial cell. Fics. 54, 55.—Two rhizoids formed by the undivided spore. PLATE XIII All figures X75 Fics. 56-64.—Photographs of living prothallia which, with many others, were taken at one time from one small bit of soil; only enough are shown to indicate the variation in form and growth. BOTANICAL GAZETTE, LVII PLATE XII PICKETT on CAMPTOSORUS BOTANICAL GAZETTE, LVII PLATE XIIl ae ee PICKETT on CAMPTOSORUS CURRENT LITERATURE BOOK REVIEWS Genetics Some one once said, perhaps more epigrammatically than truthfully, “the progress of a science is in direct proportion to the mathematics used in its development.” Whether generally true or not, the constant and rapid progress of genetics since the introduction of Mendel’s mathematical notation is a great argument in favor of the statement. At the same time, the chaos that can in mathematics were the first to forget that their science is merely a shorthand method of stating the facts, that no more can come out than goes into the mill, though it should come out in a shape more conducive to thorough mental digestion. The slogan of certain biometricians, “there are no premises, all is treatment,” has brought many biologists to that state of mind in which they could take seriously Por’s sly dig in the “Purloined Letter.” In speaking of the necessity of putting oneself in the mental attitude of the thief if the hiding Place of the stolen letter were to be discovered, he says: ‘‘As poet and mathe- matician, he (the thief) would reason well; as mere mathematician he could not have reasoned at all.” It remained for JoHANNSEN to prove that he is poet, biologist, and mathe- matician, by showing some four years ago the true relation of KARL PEARSON’S beautiful developments of mathematical methods to _ jriactis The motto through the whole 25 chapters of his 500-page book was: “Wir miissen die Erblichkeitslehre mit _— nicht aber als Mak treiben!”’ JOHANNSEN’s work on the comp e permanence of homozygous types pub- lished under the title Ueber eae ke in Populationen und in reinen Linien (1903) had already been enthusiastically received by many investigators, partly by reason of the author’s mastery of a persuasive style and partly because the conclusions fitted data with which his readers were personally familiar. For these reasons, this elaboration of his ideas met with a cordial reception that is not the fate of many textbooks. But one unfavorable criticism of any impor- ee could be made. The author did not treat adequately the numerous genetic researches in which the problems of heredity had been attacked by methods unlike his own. There is no hesitancy, therefore, in saying that the new edition, with its 30 chapters and 722 pages, to which this criticism may not : * JOHANNSEN, W., Elemente der exakten Erblichkeitslehre. Zweite Auflage. VO. pp. xi+723. figs. a5 Jena: Gustav Fischer. 1913. 239 240 BOTANICAL GAZETTE [MARCH be applied with justice (if one excepts cytological research), will be a welcome wea to genetic literatur s present form, the a might very easily be divided into two books with sce titles that could be used independently. The one is a thorough introduction to statistical methods as they should be used in the service of iology; the other is a well balanced discussion of the present status of genetic conceptions. might be expected, it has been the general discussion of heredity that has received the bulk of the revision; the chapters on biometry were admirably done in the first edition, and the static nature of their substance was such that little change has been necessary. Scarcely a word has been altered in the first five chapters, though CHARLIER’s short method for determining the standard deviation has been added. In chapter 6 the discussion of mean error has been ‘revised and a demonstration from the domain of plant physiology has been added. From this point to chapter 22, only chapters 12 and 13 are new, but the remainder of the book is entirely as written. In chapter 12 the more recent investigations concerning the possible effect of selection on pure lines are described, while in the next chapter the “misunder- standings” of certain authors who have opposed the theory of permanence of homozygous types are taken up and disposed of with very clear logic, though the style of the rejoinder is sometimes a little caustic. The last seven chapters of the book are so crowded with information that only a hint as to their contents can be given. They must be read by all who are interested in genetics. Sixty pages are given up to the influence of the factors of environment on variation and 160 pages to Mendelism in its various phases, including heterozygosis, inbreeding, sterility, coupling, and sex determi- nation. Mutations are considered rather concisely in the next to the last chapter, the author being rather of the opinion that the peculiar behavior of Oenothera Lamarckiana will ultimately be shown to be the result of segregation and recombination, as has been suggested recently by HERIBERT-NILSSON. The final chapter is a résumé, with observations on eugenics, race hygiene, and evolution. With reference to the position taken in his earlier Seg concerning the action of selection, the author remains as firm asarock. Hea ds further data of his own to support his position and shows very clearly hie the seemingly opposing conclusions of various investigators either are due to fallacious reasoning or are based upon material that is not easily divested of complications that confuse the main issue. To critics who deal only with generalities ~ makes the following reply that may well be taken to heart by those who d with evolution from an easy chair: 5 Man hat mich kurzsichtig genannt, in Bezug auf die Selektion. Ich gree dies mit Vergniigen; die Priimissen einer oft maszlosen spekulativen Fernsi waren ja gerade zu untersuchen und wiirden wertlos striate 1914] CURRENT LITERATURE 241 It will doubtless surprise many that JoHANNSEN maintains a firm Lamarckian attitude throughout his book, dealing particularly sympathetically with the work of Semon. He says: “Man hat mich ferner ‘reiner Weisman- nianer’ genannt. Jeder solche ‘man’ hat mein Buch nicht gelesen oder nicht verstanden.”” The reviewer must admit, therefore, that he has not understood the author, for after reading the volume he is still firmly convinced that in its essentials it is more nearly Weismannian than Lamarckian. O course he would not accuse the author of maintaining the morphological by most biologists as belonging rightly within the scope of WEIS : conception of heredity. 8B us.” In addition he has adopted WEBBER’s term “clone” for a bud Taken all in all, one must be very critical to have anything but praise for the new Erblichkeitslehre, and it is confidently predicted that it will long remain . EAST. a classic.—_E, M. E MINOR NOTICES North American Flora.2~—Volume 15, part 1, contains the Sphagnaceae by Alpert Le Roy ANDREWS, the Andreaeaceae by ELIZABETH GERTRUDE Berton and Juuta Trrvs Emerson, and the Archidiaceae, Bruchiaceae, Ditrichaceae, Bryoxiphiaceae, and Seligeriaceae by ELIZABETH GERTRUDE IAMS. New combinations occur in Sphagnum, Ditrichum, Di- cranella, Campylopodium, Oncophorus, Austinella, Leucoloma, and Dicrano- Jum. New species are described in the following genera: Dicranella (2), Dicranum (1), Campylopus (4), and Octoblepharum (1). Volume 22, part 5, is voted to a continuation of the Rosaceae by PER AXEL RypBERG and con- tains the genera Poterium to Rubus inclusive. New species are described in ~ following genera: Agrimonia (2), Adenostoma (1), Geum (4), Sieversia (1), ewonic (1), Cercocarpus (7), and Rubus (19).—J. M. GREENMAN SUN eer *North American Flora. Vol. 15, part 1, pp. 1-75, June 14, 1913; part 2, * Na August 8, 1913. Vol. 22, part 5, pp. 389-480, December 23, 1913- New York Botanical Garden. 242 BOTANICAL GAZETTE [MARCH Fossil plants.—PELouRDE’ has contributed the first published volume to the “Bibliothéque de re ”? which in turn is one of the 40 divisions of the “Encyclopédie scientifique’ under the general direction of TOULOUSE. Under Paleontology, 15 volumes are projected, 3 of which are to be on Paleo- botany. The two others will deal with gymnosperms and angiosperms e present volume is a compact summary of our knowledge of fossil cryptogams, all but 22 pages being given to pteridophytes. The completeness of the abr ate may be judged by the fact that the bibliography includes 256 titles. J. .M. C. Identification of trees.—In order to meet the demands of teachers for a serviceable key for the identification of trees in their winter condition, the authors of Trees in winter have reprinted that portion of the volume containing the keys to genera and species.4 As indicated in the review of the ori volume,s these keys are based upon the bud, leaf-scar, twig, and occasionally upon the fruit characters. It is anticipated that the convenience of the key in a separate form will be appreciated as an important addition to the equipment for the winter study of our tree flora—Gro. D. FULLER NOTES FOR STUDENTS Self-sterility—CorreNns® has recently made the phenomena of self- sterility in plants the basis for a searching genetic investigation. After some preliminary experimentation, Cardamine pratensis was selected as the material best suited to his purpose, especially as some light had already been thrown upon self-sterility in this species by the investigations of Jost and HILDEBRAND. Correns began his study with two specimens of Cardamine pratensis, which though nt from the same source (Munster Botanic Gardens differed markedly in many characters, and were both self-sterile. These two plants (for convenience labeled B and G) were crossed reciprocally. The offs spring, in number, were tested out individually for self-sterility by pollinations (1) from the parents, (2) on the parents, and (3) from sisters. The results are given in such great detail and with such a large amount of easily follow tabular data, that no critic of modern genetic experimental work can criticize the evidence presented on the ground that the details are not all given, oF that 3 PELOURDE, FERNAND, Paléontologic Lininy (Cryptogames cellulaires ¢t vasculaires). 16mo. pp. xxviii+360. figs. 80. Paris: Octave Doin et Fils. Fr. 5- 4 BLAKESLEE, A. F., and Jarvis, C. D. ihe hea. of trees. Key to genera and species from “Trees j in winter.” Sto: p. 16. New York: Macmillan & Co. 1913. 30 cts, For sale only by the eet Storrs, Conn. 5 Bor. GAZ. 56:79. 1913. ‘ Correns, C., Selbststerilitat und Individualstoffe. Biol. Centralbl. 33*3°7 423. pls. 1-17. 1913 1914] CURRENT LITERATURE 243 the language is so technical that transmutations must be made before an ordi- nary biologist can understand it. When the F, plants derived from the crosses (BXG and GX B) were back-pollinated with B and G, their behavior in refer- ence to seed-setting indicated that they could be separated into four more or less distinct classes: (1) plants fertile with both B and G; (2) plants sterile with both B and G; (3) plants fertile with B, but sterile with G; (4) plants sterile with B, but fertile with G. Numerically, the 60 F; individuals were found to distribute themselves among the four classes in about equal propor- tions, the actual numbers being 16 bg:16 bG:14 Bg:14 BG. Crosses between the individuals of these four F, classes, 720 of which were made, in the main confirmed the results obtained through back-crossing with the parents. Crosses between different F, plants and plants obtained from foreign sources all resulted in well-filled capsules. From the facts presented, the conclusion that two inhibitors were operating to present self-fertilization Was a most natural and simple interpretation. Accordingly, CoRRENS gives to those F, plants fertile with both B and G, the formula dg, indicating the absence of both inhibitors; those plants fertile with one parent and sterile with the other are either Bg or bG, indicating the absence of one and the presence of the other inhibitor; and lastly, those plants sterile with both B and G are said to be BG, indicating the presence of both inhibitors. CorrENs does not dog- tize as to the nature of these inhibit except to say that they are hereditary constituents of the germ plasm, which appear to segregate in Mendelian fashion some time prior to the complete development of the egg cells and pollen grains, Hence, self-sterility is not a phenomenon of “Individualstoffe” in the Sense in which this term was used by Jost. In Correns’ scheme of interpretation, his two original plants are hetero- zygotes, B represented as Bb and G represented as Gg, the letters indicating the Presence and absence of two distinct factors for self-sterility. Bb gives rise to two kinds of gametes, those with the inhibitor (B) and those without It (b). Gg likewise produces gametes with G and gametes from which it is absent (g). Bbx Gg is fertile, but neither Bb Bb nor GgXGg would result in seed-formation, as the presence of the factor B would inhibit the growth of the Pollen from the Bb type. The same is true regarding plants of the Gg type. The cross BbX Gg results in the four types BG, Bg, bG, bg, the classes actually tained as ascertained by the pollination tests. Types BG, Bg, and 0G are self-sterile, while type bg should be self-fertile. Plants of the bg type should be fertile with the other three types; type bG is fertile with only Bg; type 6G with only Bg; while BG is fertile with only bg. It is obvious that types BB and GG could never be formed. Correns’ interpretation of his results opens itself to numerous criticisms, for even the most ardent supporter of Mendelian universality would question the actuality of the four classes. Neither the data from the back-pollination “xperiments nor the data from those in which F, sisters were crossed give any notion of clear-cut classes, such as MENDEL secured in his pea work. For 244 BOTANICAL GAZETTE [MARCH example, bg bg should be fertile, but in the tabular data one finds some bg plants giving “alle gut,’’ some giving “‘alle nichts,” and some “3 nichts, 3 gut” in crosses, and, so far as the reviewer can ascertain, no g plant was fertile to its own pollen, each attempt invariably resulting in “alle nichts.” The testing out of the 60 F, plants (BXG, GX B) with the parents gave similar results. Type dgXB and XG gave satisfactory evidence of complete fertility in only about a fourth of the cases, the others varying in proportions of “nichts” and “gut”? on each plant tested. CoRRENS recognizes these difficulties and only advances his interpretation as a crude, but helpful, working hypothesis. He believes there are many different lines of C. pratensis, and that these differ mu in genotypical constitution, so that the various irregularities whereby his actual data differ from the theoretical expectation are assignable to this cause, that is to say, there were still other inhibitors at work of which he took no notice. In support of this conclusion, he points out that “keines der 60 Geschwister war einem anderen oder den Eltern véllig gleich”; also, the results secured by crossing these F, sisters with the two foreign races. Another complication encountered by CorRENS was the reaction of the same plant toward the same pollen at different times, at one time pollinations resulting in “gut,” at other times “‘nichts,” the result possibly of obscure environmental changes. ORRENS is to be congratulated on again being a pioneer in opening up 4 new field to a new viewpoint. (e) N? in two papers has also contributed to the elucidation of self- sterility phenomena. Darwtn’s observations on the existence of self-fertile sterile X self-sterile gave only self-sterile offspring. Certain self-fertile plants when self-fertilized gave only self-fertile offspring; when crossed with sell- sterile plants, the same result was obtained. Other self-fertile plants when In his second paper, Compton critically reviews the work of MORGAN; Jost, CORRENS, and other earlier investigators of this phenomenon. Until eg investigations of these men, the term self-sterility was a veritable “catch-all. The general notion was extant that a self-sterile plant was fertile with the pollen of every plant of that particular species or race, a condition which all ahs investigators have shown to be untrue. Many records of self-sterility in species rest on faulty observation; in some cases no evidence was at hand to show that 7 Compron, R. H., Preliminary note on the inheritance of self-sterility in Reseda odorata. Proc. Cambridge Phil. Soc. 17:7. 1913. ———, Phenomena and problems of self-sterility. New Phytologist 12:197-205- IgI3. t914] CURRENT LITERATURE 245 pollen had ever reached the stigma, or that having reached it, favorable con- ditions for germination were present. Laburnum vulgare, as a case in point, * remains self-sterile in the absence of slight mutilations produced by insect visitors. Many examples of species with both self-sterile and self-fertile races or varieties are mentioned. An enormous variation in the degree of self- sterility is noted: at one extreme, self-pollination produces but slightly fewer seeds than cross-pollination; while at the other, a few cases are known in which the stigma and pollen of the same flower are mutually poisonous. Environ- ment produces a marked effect on this phenomenon, as often a change in climate changes self-sterile plants to self-fertile ones. Biophytum sensitivum is recorded as self-sterile in its open and self-fertile in its cleistogamous flowers. owledge of causes is exceedingly vague and fragmentary. Examination of stigmas fertilized with their own pollen has shown that although germination ‘takes place, the pollen tube is inhibited in its growth in some way so that it never reaches the embryo sac. In Jost’s experiments no artificial medium was discovered in which pollen tubes would grow their normal length. ComPTON Suggests the presence of a soluble diffusible substance in the stigmatic or stylar ssues which acts in a positive manner toward promoting pollen tube growth. An analogy between self-fertility and immunity, and self-fertility and infection is drawn, in line with the suggestive work of Jost, Scutrr-GroRGIONI, and others. A special section is devoted to a review of the investigations of BAurR, Correns, and Compton, on the inheritance of self-sterility, and its racial as °pposed to its individual nature. Suggestive analogies are also drawn between self-sterility and certain sexual phenomena, such as non-conjugation and The wood of Pinus.—Groom and Rusxron;? in their detailed account of the wood of the five East Indian pines, have kept several objects in view: the affinities of the species, tropical (hydrophytic) or xerophytic features of the Wood structure, relationship of the latter to leaf structure, and the nature of the so-called “ Sanio.” They have devoted the first part of their work e # general statement and discussion, and in the second part have given a etailed escription of each species. : _ P. excelsa and P. Gerardiana belong to the HapLoxyLon section, having Single bundles to the leaves, deciduous sheaths on the spurs, tangential pitting Cir of ae Groom, PERcy, and Rusuton, W., Structure of the wood of East Indian species ab i - Jour. Linn. Soc. Bot. 41:457-490. pls. 24,25. 1913. GROOM has also given aoa account of the critical identification of the wood of the five East Indian pines in n Forester 39:409-411. 1913. 246 BOTANICAL GAZETTE [MARCH on outermost tracheids of the summer wood, and ray tracheids with almost smooth walls. In P. excelsa the needles are in fives and the umbo of the cone scale is terminal. The ray pitting of the tracheids, too, is of the large simple © type (Grosseiporen). It thus belongs to subsection CemBra, and having eee cones and thin cone scales belongs to the Sirobus group. They note that, ‘ regards width of spring-tracheids, the American species, belonging to Ps section HAPLOXYLON that most closely approach it, likewise belong to the group Strobus,”’ but draw attention to one difference, the thick horizontal walls of the ray cell of P. excelsa, which, according to PENHALLOW, is not character- istic of the Cempra type. P. Gerardiana has a thick cone scale with central umbo, three leaves to the fascicle, and so belongs to the subsection PaRa- CEMBRA Of KOEHNE, which has small ray pitting on ae —— Like the other haploxylic forms, it has uniseriate tracheary pit The other three species, P. longifolia, P. Khasya, rs P. Merkusti, have 3, 3, and 2 needles, respectively, but “agree not only in the diploxylic nature of the leaves, the persistent nature of the sheath of the dwarf shoot, and the possession of a central umbo on the thick cone-scale, but also in that the transi- tion from spring wood to summer wood is sudden (except in P. Khasya), the outermost tracheids of the annual ring do not universally bear pits on the tangential walls, the pits on the radial walls of the spring tracheids are often 2-seriate, and the ray tracheids are denticulate.”’ The authors consider that the pitting of P. Merkusii is of extreme interest, showing a transition between that ‘of the cordaitean or araucarian forms and the ordinary abietineous type. The pits are ‘‘in one, two, or three rows, . in peculiar nests, of 3 or 4.’’ These nests are surrounded by “‘Sanio’s rims.” The similar condition found by Santo himself in the root of P. silvestris seems to have been overlooked, but at least P. Merkusii is the only pine so far described with nests in the stem. They compare this cluster pitting to the well known condition described by PENHALLOW in Cordaites Newberryti, and to that in Cedroxylon transiens of Goran. These clusters of pits correspom to the “starlike” arrangement which Goran considers as intermediate between araucarian and typical abietinean pitting. With regard to ecological features, they state: “the tracheids are shortest (3 mm.) in the xerophilous Pinus Gerardiana, attain a length of 4 mm . in P. excelsa and P. longifolia, and 4.6 mm. in P. Khasya, and the relatively great length of 7 mm. in the tropical P. Merkusii. The size of the tracheids is also commented upon, but a separate article dealing with this point is in process of publication. It has a thick cuticle and hypoderma, much transfusion tissue and “a great development of resin ducts,” all in excess of P. excelsd. the other three they state: “‘as regards leaf structure, all have stomata on all their faces. P. longifolia, the most clearly tending to xerophily, has the thickest cuticle (hough not 80 thick as P. Gerardiana), and P. Khasya has the thinnest P. crieertgese 1914] CURRENT LITERATURE 247 in P. Merkusii this is less marked, while in P. Khasya there is no indication of such thickening. All three species contrast with the haploxylic Indian species in the feebler'development of the tissue separating the endodermis from the vascular tissue.” These structural ecological results are certainly very interesting, and Groom’s further contribution, which is already in the press, will no doubt add valuable results. It is very desirable that further studies be made on material where the ecological factors are definitely known, and also that a single species be studied ‘under its extreme of wet and dry conditions, in order to determine how much of the change is inherent in the species itself and how much is really due to the external conditions, The so-called “bars of Sanio” of the Harvard school come in for very severe criticism. They show that these are composed partly at least of pectic compounds, but not of cellulose. T hey also consider that Miss GERRY mistook SANIO’S description of trabeculae for these structures, and propose the term ‘Sanio’s rims” for them, a.terminology which is certainly much more in keep- ing with Santo’s idea (“‘die Umriss des Primordialtiipfels”). Miss GERRY, however, made a much more serious mistake, for she even quotes SANIO’S description of the torus (‘diese scheibenférmige Verdickung”’) as referring to the structures in question. Resin plates were also found in some of the tracheids adjacent to the rays and also true trabeculae. The authors have also noted the presence of tracheids with bent ends: “when abutting on a medullary ray the end may fork, or bend, SO as to run for some distance along the ray and thus form a transition towards 4 Tay tracheid.” They also found such tracheids forming radial series apart from the medullary rays The detailed description of the species is so arranged that easy reference can be had to any particular feature —R. B. THoMsoNn Some Jurassic plants—Among the pteridophytes described by THomas? from the Marske Quarry of the Middle Jurassic of the Cleveland district of Yorkshire is a new marattiaceous fern, Marattiopsis anglica. The genus is “a very common Rhetic and Liassic form, and has been recorded from Sweden, olm, Germany, Poland, and Tongking. Recently two incomplete leaflets from the Jurassic (Kimmeridge) beds of Sutherland have been placed by Sewarp in this genus. Allied forms from the Jurassic of Oregon have been described by Lester Warp and others under the old name of Angiopteridium.” # enclosing a number of loculi arranged in two rows; each loculus probably SRR _” THomas, Hucn Hamsnaw, The fossil flora of the Cleveland District of York- * I. The flora of the Marske Quarry. Quart. Jour. Geol. Soc. 69:223~251- bls, 23-26. 1913. 248 BOTANICAL GAZETTE [MARCH formed a projection, and imparted to the synangium a corrugated appearance.” The spores are small, about o. 3 mm., and densely covered with fine projections. “The usual tetrad scar is not seen on any example, but a single straight scar instead, which doubtless indicates that the spores were arranged in the spore mother cells bilaterally and not tetrahedrally.” Of the bennettitalean forms, the staminate sporophylls of Williamsonia spectabilis Nathorst are “not uncommon at Marske.” THomas has been able to make an interesting restoration figure of an almost mature staminate flower of this species. The sporophylls are united into a cup below, and probably in the young condition arched over it, straightening out at maturity. The synangia “lie in regular rows, with their long axis at right angles to the sporo- phylls,” and on the upper or inner side. The synangia of each row appear to be borne on slender stalks. “These stalks seem to have been given off on each side of the central portion of the sporophyll, and may be regarded either as lateral lobes of this organ, or possibly as arising as part of a pinnate structure like the microsporophyll of Bennettites, which is adnate with the broad structures hitherto termed sporophylls.” He concludes, however, that “whatever may have been the method of production of the synangia of Williamsonia spectabilis, this form serves (as NaTHORST believes) as a valuable connecting link between on its surface.” There is evidence also of the presence of the whitbiensis type itself in the Marske beds, and of a female strobilus of Williamsonia and other bennettitalean remains. THomas’ study of the leaves is especially interesting, hi nness in distinguishing the bennettitalean from the filicinean forms by microscopic examination of the epidermis, etc. Such critical study, which was inaugurated by NatHorst, puts the results from impressions mu more nearly on a par with those from the study of petrifactions. ne of the commonest fossil plants at Marske belongs to the Ginkgoales, Baiera longifolia, which has not before been recorded in England. THOMAS has not found a complete leaf, but judges that it must be at least 18 cm. ™ length. By its great size, and also by its epidermal structure, of which three figures are given, it is distinguished from B. gracilis, to which the specimens were previously assigned. He also found Ginkgo digitata and Czekanowskia Murrayana in the Marske beds. Of the Coniferales two forms were found, Tasxites zamioides, of which both upper and lower epidermis are described, and Elatides (Pagiophyllum) ssi Of the latter THomas reported, as his article was in process of publication, that ‘“‘many specimens of this type have been recently found at Roseberry Topping; bearing male and female cones. These seem to indicate the necessity i creating a new species, and probably a new genus for the form here described. Further study of the fossil flora of this region promises much for our knowledge of the bennettitalean and coniferous forms.—R. B. THOMSON. 1914] CURRENT LITERATURE 249 Climatic areas of the United States.—In a recent paper, LivINGsTON® has examined the various climatic data made available through the United States Weather Bureau, and finds that among the factors that may be related to plant growth, only precipitation and temperature have been measured with accuracy, and although the distribution of stations is far from ideal, the resulting data are satisfactory. The evaporation data of the Bureau are shown to be extremely meager, being limited to a single year. From the temperature tds Livincston has made a summation of the daily normal temperatures for the days within the frostless season, for a large series of stations, plotted these upon maps of the United States, and drawn isoclimatic lines. Upo these maps he has also drawn isoclimatic lines of (1) the average daily precipi- tation, (2) the average daily evaporation, and (3) the differences between the precipitation and evaporation for the same frostless period. e results are Tee maps in which are delimited areas upon the basis of temperature and upon the basis of a water relation. It is possible in this way to characterize climati- cally the area occupied by any plant or plant communit out the country for a period of 15 weeks, extending from May to September, of the prairie region and the eastern deciduous forest. This leads the author to conclude that this prairie region is a potential deciduous forest, a conclusion i accord with the success which has attended tree planting within much of this area and with the advance which the forest is at present making upon the Prairie, according to GLEASON and other workers. The mesophytism of the northwestern and northeastern conifer forest centers is demonstrated by aver- age weekly rates of evaporation of only about roo cc. The deciduous forest oo ies a region with a wee y summer rate of from 100 cc. to 200 cc., while a similar rate is shown for the southeastern conifer center, which might indicate that this formation is also potentially a deciduous forest. The semi-arid regions of the southwest show an average of from 300 cc. to 400 cc. weekly. ‘ From these and other data it appears that the summer evaporation inten- ay furnishes a climatic criterion which is more promising for vegetational Studies than any other available meteorological data. It has the further advantage of being rather easily determined by the porous cup atmometer, and meh data would also be of great importance in agricultural as well as in ecologi- cal investigations —Gro, D. FuLrer. Darter « Livincston, B. E., Climatic areas of the United States as related to plant Stowth. Proc. Amer. Philos. Soc. 52: 257-275. 1913. y 3 “Lt B. E., A study of the relation between summer evaporation inten- ln centers of plant distribution in the United States. Plant World 14: 205-222. 250 BOTANICAL GAZETTE [MARCH Cytology of rusts.—In 1912 OLIVE” described an intermingling of perennial gametophytic and sporophytic mycelia of Puccinia obtegens throughout the n shoots of P. Podophyili the order is usually reversed, REE: and aecidio- spores appearing on the leaf sheaths, and later aecidia and spermagonia on the young leaves. The mycelium in the leaf sheath is prevailingly binucleate. In the young leaves the uninucleate (gametophytic) mycelium prevails, while in older leaves the binucleate (sporophytic) mycelium becomes predominant. The aecidio- spores of P. Podophylli and the uredospores of P. obtegens and Uromyces Glycyrrhizae are all regarded as secondary in origin and thus apogamously derived, arising solely from the binucleate mycelium, as the reviewer formerly pointed out in the first mentioned case. No sexual fusions were found in the young sori in which the mingled gametophytic and sporophytic mycelia occur. The binucleate cells of the sporophyte push in among the uninucleate hyphae of the gametophyte and there form spores directly. Otitve:believes this apogamous condition to be a result of the perennial habit. rmatia alone arise from the uninucleate gametophytic mycelium, although. binucleate hyphae often invade the immediate neighborhood of the spermagonia. The reviewer, being unaware of this curious mixture of the two kinds of mycelium, in which binucleate hyphae may become predominant, was led to believe the spermatia, like the apogamous aecidiospores, might arise from distribution were observed: (1) an unlimited growth of the perennial sporo- phytic mycelium alone in P. obtegens and Uromyces ae producing only secondary uredospores and teleutospores in confluent sori, an d (2) a localized distribution of the binucleate sporophytic mycelium, giving rise to 4 sorus of teleutospores in P. Podophylli, or in the other two species to the local- ized “summer generation” or opiate generation,’ producing secondary uredospores and teleutospores.—L. HARP, 2 OxivE, E. W., Perennial ee and sporophytic generations in P uccinia oblegens (Lk.) Tul. Science 35:150. 8 OLIVE, E. W., Intermingling of Saaleica sporophytic and — ee tions in Puccinia Podophylli, P. obtegens, and Uromyces Glycyrrhizae Ann. Myc EE :207-315,. Pt. 15. 3033. «4 SHarp, L. W., Nuclear phenomena in Puccinia Podophylli. Bot. Gaz. 512493» 464. Igri. 1914] CURRENT LITERATURE 251 Seedling anatomy of Lupinus.—BECQUEREL® has studied the development of the lupine (L. albus and L. luteus), applying to this plant the “dynamic” method, by which he correlates the diverse results of other botanists and shows how these differences have arisen. He also utilizes his results to combat vari- ous current views of the transitional region of the seedling. This “dynamic” method is much in vogue among a group of French botanists, headed by HAUVEAUD. Instead of taking a seedling of no definite age, plants of all ages and stages in development are studied and compared. This is the method of necessity employed in studying animal development, but has been considered of little importance in plants, because of the slight amount of ‘making over”’ of vegetable tissues which is possible. BECQUEREL, however, does claim that a most important change of this nature takes place in the hypocotyl—the absorp- tion of the primary wood, which in the young plant comes up very high in the cotyledonary region and in the older plant is not found at all in the same region and only in a vestigial condition at a lower level. This variation in structure has no doubt led, as BECQUEREL claims, to the diverse statements as to the height at which the traces of root structure have been found by different inves- tigators, but that it is due to the absorption of the primary wood and has the phylogenetic significance that BECQUEREL ascribes to it cannot be accepted on the evidence presented. I find no statement to indicate that BECQUEREL has taken into account a very obvious and natural cause for the disintegration of the primary wood. There is a rapid enlargement and elongation of the elements in the hypocotyl, in contrast to the merismatic activity of the more apical parts. In this growth the tracheary elements naturally cannot take part, and in consequence become dissociated and disorganized, their function being assumed by the secondary elements which now appear. Again, Brc- QUEREL’s statement that these elements have disappeared by reason of absorp- ion, as in animal tissues, postulates the presence of an enzyme such as hadromase, and this has not been shown to occur in any plants except the xylophilous fungi. __ The objections that BECQUEREL raises to the current views of the transi- Hon region between stem and root will lead, no doubt, to clearer ideas and Wording of the subject in future texts.—R. B. THoMson. Sea-water and the distribution of plants.—The discovery of any efficient means of determining in a quantitative manner the factors limiting the extent and composition of various plant associations must be regarded as an important Contribution to ecology. In salt marshes the concentration of salt in the soil water has long been regarded as a limiting factor, and now HARSHBERGER™ has oe : S Becqueret, P., L’ontogénie vasculaire de la plantule du lupin. Ses consé- quences pour certaines théories de l’anatomie classique. Bull. Soc. Bot. France 60: 177-186. pl. 4. figs. 5. 1913. - HARSHBERGER, J. W., An hydrometric investigation of the influence of sea-water on the distribution of salt marsh and estuarine plants. Proc. Amer. Phil. Soc. 50:457- 496. pls. 2. figs. 7. IQIL 252 : BOTANICAL GAZETTE ; [MARCH measured this concentration by means of a convenient type of hydrometer, of accommodation; while Spartina stricta maritima, S. patens, and Juncus Gerardi show the wridaet limits. Typha aiiiafais cannot grow in water that approximates a sodium chloride content of 1 per cent, and in much less dilute solutions shows the detrimental effect of the salt. From a large number of determinations, the height of the plants and the size of their spikes are shown to vary inversely with the concentration of the water in which they developed, the optimum condition being entirely fresh water. The paper con- tains other valuable data and points the way for intensive studies of the vegetation of salt marshes and alkaline soils. A few notes on the deposits shown in sections of the salt marsh soil indicate a definite succession in the former vegetation similar to that at present in progress, and that there has been a progressive submergence of the marsh either from a change of tidal level, as held by JoHNSON,” or from a general sub- sidence of the entire coast line, as is believed by most investigators.—GE0. D. FULLER. Queensland ferns.—Dr. F. M. BaItEy, the veteran colonial botanist of Queensland, Australia, has just published an interesting review® of Domin’s work on Queensland plants, so far as it concerns ferns and fern allies.” The new species ve —— = hi as S species new to Se * are listed, it with description f the review is the aln cism of Deen's: S new species and varieties. For example, in jean to Pallas triquetrum Sw. var. fallacinum Domin, he says that “the distinctions given seem only those of growth and situation”; Selaginella flabellata F. v. M. var. brevispica Domin “‘is scarcely worthy of a dikiactiee name”; Marattia oreades Domin “‘can hardly be separated from that very variable species M. fraxineo Sm.”; in regard to two new varieties of Platycerium alcicorne and one new variety of P. grande he says that “it is scarcely advisable to attach names to isolated plants of Platycerium, particularly as differences in their growth and form are so often caused by situation.” ‘“‘Finally,” says BamLey, “1 think that 7 JONSON, D. W., The supposed recent subsidence of the Massachusetts and New Jersey coasts. Science N.S. 32:721~723. 1910; also Botanical evidence of coastal subsidence. Science N.S. 33:300-302. 1911; also Bor. Gaz. 56:449-408. 1013- 8 Bartey, F. M., Contributions to Queensland flora. Bot. Bull. no. 17- PP- ' 1913. ™ Domin, K., Beitrige zur Flora und Pflanzengeographie Australiens I. Abt. Pieridegiees CPioditesas einer Farnflora Queenslands). Stuttgart. 1913- 1914] CURRENT LITERATURE 253 had Dr. Doorn had a longer experience with our ferns, and observed the great diversity of their form and growth, he would have realized that some of his new kinds were but growths of well known species.” Nearly 70 years of experience with plants in the field, much of it with Queensland plants, add to the weight of BAILEY’s comments. At the time of OMIN’S visit, the present reviewer was collecting morphological material in Queensland, and can heartily agree with the remarks regarding the variability of Psilotum, Marattia, and Platycerium. In Platycerium, particularly, the appearance of the plant is so affected by its position on the tree, that isolated plants might be described as new species, if the differences were not so obviously due, in some cases, to merely mechanical causes.—C. J. CHAMBERLAIN. A new seed genus.—Miss BENSON” has made Conostoma ovale Williamson the basis of a new form genus, which she calls Sphaerostoma. Along with C. ovale the doubtful species C. intermedium is included as S. ovale. In general structure the seed resembles Lagenostoma, and is found most frequently with- out its cupule (or outer integument), from which it doubtless separated when drop All of the epidermal cells of the integument are papillate, and at the apex, where the integument is free from the nucellus, they become so elongated as to form a whorl of epidermal crests, the ‘‘canopy”’ being 8-lobed. These crests Miss BENSON calls “‘frills.”’ The structure of the lagenostome, however, is quite peculiar. There is the usual central column of nucellar tissue, surrounded by the moatlike pollen chamber which is invested by the epidermis of the nucellus. But the roof of seed Pollen chamber is modified into what Miss BENSON regards as “an elas- tcally acting mechanism” which definitely closes the pollen chamber after there has been a dehiscence which admits*the pollen grains. This elastic mechanism, forming the roof of the pollen chamber, is the epidermis so modi- ed as to resemble in appearance a multiseriate annulus. The conclusion is at in dehiscence this mechanism straightens elastically, admits pollen grains, and then closes the chamber again. The seeds are provisionally referred to Heterangium Grievii on what seems ‘0 be excellent evidence, namely constant association, suggestions of actual continuity of ovules with the parent plant, and the evident morphological relationship to Lagenostoma.—J. M. C. . ; Culture of Opuntia.—Grirrirus* records some very interesting observa- Hons upon the behavior of certain species of Opuntia under culture. e Plants were grown at the government stations at Brownsville and San Antonio, eC ei eaee ®” Benson, Marcaret J., Sphaerostoma ovale (Conostoma ovale et intermedium Williamson), a Lower Carboniferous ovule from Pettycur, Fifeshire, Scotland. Trans. Roy. Soc. Edinburgh so: 1-1 5. fies. 3. pls. I, 2. 1914- * GRIFFITHS, D., Behavior, under cultural conditions, of species of Cacti known 4s Opuntia. U.S. Dept. Agr., Bur. Pl. Ind., Bull. no. 31. pp. 24. pls. 1-8. fig. I- 1913. 254 BOTANICAL GAZETTE | MARCH Texas, and Chico, California. At each of these places between 600 and-1500 varieties of Opuntia were under cultivation. The general purpose of the inves- tigations was economic, but incidentally the behavior of these plants was very suggestive. Spiny plants grown near the coast of Texas mature spines much more slowly than in drier regions. Changes in the environment seem to have more effect on the production of spicules (bristles) than of spines, the evidence indicating that conditions unfavorable to vegetative production stimulate the growth of spicules. An interesting contrast between the conditions in Southern Texas and California is shown by the fact that the former region is favorable for the production of vegetative growth, while California is better adapted to fruit production. It was found that many species are not promising for breed- ing purposes because of lack of variability; they are very constantly spiny, and spine protection seems to be directly proportional to plant vigor. The power of recovery from the effect of low temperature is rémarkable, especially when the succulency of the plant is considered. very interesting observa- tion was that in many of the species, especially the larger ones, the plants grown from cuttings and those grown from seeds are very different in appear- ance; the latter are tree-like and the former are headed on the ground without distinct stems.—J. M. C. Mitosis in Conjugatae:—In agreement with the earlier work of LUTMAN, VAN WISSELINGH” finds that the nuclei of Closterium show at all stages an essential correspondence with those of higher plants. Division is strictly mitotic, and the chromosomes, more than 60 in number and of various lengths, all come directly from the reticulum, which is composed of but one material. They are not placed in a ring around a central spindle at metaphase, as LAUTER- BORN thought, but form a uniform plate of the usual type. VAN WISSELINGH denies the presence of a continuous spirem at prophase and telophase 4s reported by Lurman. The nucleolus is not of the peculiar kind previously described for Spirogyra; in C. Ehrenbergii it is really an agglomeration of many small nucleoli. No centrosomes were foun In Eunotia,® also, the nucleus divides mitotically, as in other diatoms, but well developed chromosomes are not formed. The nuclear reticulum gives rise to small irregular bodies which become arranged in the form of a “nuclear plate” around the characteristic “central spindle” of the diatoms. The nuclear plate divides to form two daughter plates. VAN WISSELINGH’s results here agree with those of KLEBAHN and KarsTeEN on other diatoms, but not with those of LAUTERBORN, who found in several species long and well developed chromosomes in both mother and daughter nuclei. 2 Van WisseLincu, C., Uber die Kernstruktur und Kernteilung bei n=. Siebenter Beitrag zur Kenntnis der Karyokinese. Beih. Bot. Centralbl. 29*:499-43* pl. 10. 1913. VAN WISSELINGH, C., Die Kernteilung bei Eunotia major Rabenh. Achter Beitrag zur Kenntnis der Karyokinese. Flora 105: 265-274. pl. 10. 1913- 1914] CURRENT LITERATURE 255 The value of these contributions is unfortunately impaired by the small size and diagrammatic character of the illustrations —L. W. SHARP. Morphology of Tetraclinis.—SaxTon* has investigated Tetraclinis articu- lata, the “gum sandarach”’ tree of Morocco and Algeria. He has given an land connection to Australia. This would make Widdringtonia the most Primitive of the Callitris forms.—J. M. C. _The absorption of water by aerial organs.—It is now pretty generally believed that the absorption of water by the aerial organs of vascular plants 's rarely a thing of consequence outside of the Bromeliaceae, although it has n known for a long time that flaccid leaves immersed in water recover their turgescence. Experiments made by various investigators have shown that the cell Sap of Salicornia and other salt marsh plants has an osmotic pressure con- ; siderably above that of sea water. Hence the question arose with Miss HaLKET as to the Possibility of such plants absorbing water when immersed at high tide. It was found that the aerial organs of Salicornia plants can absorb water from 4 3 Per cent solution of sodium chloride, and a larger amount from distilled water.** As might be expected, the amount absorbed is greatly increased if the plants are allowed to transpire freely before immersion, without being able to absorb water through the roots. Experiments made on non-halophytic ti ts under similar conditions resulted in a loss of water rather than in absorp- on, hence it is concluded that the absorption noted in the salt marsh plants ea ny Saxton, W. T., Contributions to the life-history of Tetraclinis articulata Masters, a. notes on the phylogeny of the Cupressoideae and Calltroideae. Ann. ¥ 27:577-605. figs. 9. pls. 44-46. 1913. cal. orate ANN C., Some experiments on absorption by the aerial parts of certain plants. New Phytol. 10:121-139. r91t. 256 BOTANICAL GAZETTE : [MARCH is due to the high osmotic pressure. It is suggested that in these plants absorp- tion by aerial organs (involving both sea water and atmospheric water) may in nature supplement root a although the latter doubtless is the more important.—H. C. Cow Xerophytic fern prothallia.—The very delicate character of fern prothallia in general and their usual development under humid conditions have made it cult to account for the establishment of various ferns in dry, rocky situa- tions. Some light has recently been shed upon the subject by experi cultures of the prothallia of Camptosorus rhizophyllus by Pickett.% Exposed to conditions of desiccation arranged to simulate as far as possible ‘those of dry limestone ledges under conditions of natural drought, the prothallia showed complete recovery after 34 days, and 25 per cent recovery after 55 days. Under rather more rigorous conditions, only 50 per cent of the prothallia died after 38 days’ exposure to conditions of drought that killed all the prothallia of Onoclea Struthiopteris in 48 hours; while under the most rigorous aridity in @ sulphuric acid desiccator a small proportion of the prothallia survived 4 days’ exposure. All these tests go to prove that the drought-resisting character of the prothallia of Camptosorus must be a very important factor in the establish- _ ment of this fern in its characteristically xerophytic habitats —Gro. D, FULLER. Rhodophyceae of the Indian Ocean.—Mrs. WEBER VAN BOSSE” has reported upon a collection of Rhodophyceae made in 1905 on the Percy Sladen Trust Expedition to the Indian Ocean. The geographical distribution shows a great resemblance between the algal flora of the Indian Ocean and that of the Malay Archipelago, as well as that of the east coast of Africa. A table shows the locality, bottom, depth, and distribution of each of the 79 species collected, among which there are 18 new species, and a new genus (P. seude- nosiphonia) of Rhodemelaceae.—J. M. C. Plant — making recognizes Th groups as ‘disest Thallophytes 79,450, of which the Ascom Basidiomycetes include 64,000; Bryophytes 16,600; Pteridophytes 4,524; Gymnosperms 540; Angiosperms 132,500.—J. M. C. # PicKETT, F. L., Resistance of the prothallia of Campiosorus rhizophyllus to desiccation. Bull. Torr. Bot. Club. 40:641-645. 191 27 WEBER VAN Bosse, Mrs. A., Marine algae, chotenhiecai of the ‘“Sealark” expedition, collected by Mr. J. STANLEY Garnier. Trans. Linn. Soc. London ei II. 8:105-142. pls. 12-14. 1913. % Bessey, CHARLES E., Revisions of some plant phyla. 73. 1914. Lincoln, Nebraska. Univ. Studies 14" ae ae ee Volume LVII Number 4 i THE BoTANICAL GAZETTE Editor: JOHN M. COULTER ar APRIL 1014 2 The Effect of Shading on the Transpiration and Assimilation of the Tobacco Plant in Cuba Heinrich Hasselbring A Preliminary Inquiry into the Significance of Tracheid- Caliber in Coniferae Percy Groom Note on the Ascosporic Condition of the Genus Aschersonia Montagne Roland Thaxter | Morphological Instability, Especiaffy in Pinus radiata Francis E. Lioyd Life History of Porella platyphylla Florence L. Manning The Effect of Climatic Conditions on the Rate of Growth of Date Palms A. E. Vinson Briefer Articles The Type Species of Danthonia A. S. Hitchcock A Method of Handling Material to Be Imbedded in Paraffine . Elda R. Walker E. M. East A Correction Current Literature The University of Chicago Press 3 CHICAGO, ILLINOIS, U.S.A. Che Botanical Gazette A Montbly Journal Embracing all Departments of Botanical Science Edited by JoHN M. CouLTeErR, with the pease of a members of the botanical staff of the Uni y of Chi Issued pi 15, 1914 Vol. LVII CONTENTS FOR APRIL 19134 No, 4 THE EFFECT OF SHADING ON THE TRANSPIRATION AND xyapoeersaso nae i OF: te TOBACCO PLANT IN CUBA (wits one FicuRE). Heinrich Hasselbring 257 A PRELIMINARY INQUIRY INTO THE SIGNIFICANCE OF TRACHEID- CALIBER IN CONIFERAE. Percy Groom NOTE ON THE epeereic CONDITION ‘OF THE GENUS "ASCHERSONTA MONTAGNE VEN FIGURES). Roland Thaxt. 308 Seb OL OCIA. INSTABILITY, BSPECIALLY IN PINUS RADIATA (were TWO FIGURES AND PLATE XIV). Francis E. Lio 344 LIFE jog OF PORELLA PLATYPHYLLA. Co ONTRIBUTIONS FROM THE Hig Boranteat RATOR WITH PLATES XV AND Xv1). Florence L. Manning 320 THE EFFECT OF peo gama sa? apse ps = — oSrbike * GROWTH OF DATE PALMS (wir FIGURE). A. E. Vins 324 BRIEFER ARTICLES THe Type Species or DAntHonta. A. S. Hitchcock - sp spas A METHOD oF abo = ana nag TO Be IMBEDDED IN Picioowe (wins ONE ve wiouns): rap R. Walker 33° : aie Be ee ie rk ee a c URREN: a EEA URE $3 ss - - = Se pees aR OF WESTERN CHINA. FLORA OF MANILA. -A PLANT PHYSEQLOGY. DISEASES _OF TROPICAL PLANTS. A WEED FLORA MINOR NOTICES Pe EL £ ti a wf s ge 5 ee a - Seas & NOTES FOR srupENTs = i is ‘~ ss s reg 2 i ‘é e - ~ 335 The tio is published pee The subscription price is $7.00 per year; the e price of single ‘copies is i: cents. 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Twent: five ceparates m4 articles without covers will be supplied wae. or erties A table erga approximate cost of additions al se OS oir sony will be sent ¢ : es is Hive en an order blank which accompanies the ee Pa ig. VOLUME LVII NUMBER 4’ THE | BOTANICAL “GAZEr se APRIL 19%4 THE EFFECT OF SHADING ON THE TRANSPIRATION AND ASSIMILATION OF THE TOBACCO PLANT IN CUBA HEINRICH HASSELBRING (WITH ONE FIGURE) Introduction This paper gives an account of experiments conducted in West- em Cuba for the purpose of determining the effect on transpiration and assimilation in the tobacco plant of the cheese-cloth shade which is frequently used in that region for shading tobacco. A comparative study of the transpiration and assimilation of the tobacco plant under normal conditions and under the conditions induced by cheese-cloth shading is of interest for several reasons. First, although investigations' of the influence of different light intensities on transpiration have nearly always led to the conclusion that the rate of transpiration is decreased with a lessening illumina- tion, the experiments which have established this conclusion have necessarily been conducted with plants or parts of plants which could be kept under observation only for short periods of time, and often under laboratory conditions. Data permitting a comparison of the transpiration of plants under normal conditions with others of the same kind shaded during their entire development are not at * Kout, G., Die Transpiration der Pflanzen, etc. pp. 52-74. 1886; BURGERSTEIN, A., Die Transpiration der Pflanzen. pp. 85-103. 1904; Livrneston, B. E., Light intensity and transpiration. Bor. Gaz. 52:417-438. Ig1t. 257 258 BOTANICAL GAZETTE [APRIL hand?" Second, in view of the fact that a large portion of the tobacco crop is grown regularly under shade, such data would not be devoid of practical interest, especially in regions like Western Cuba, where annual crops require irrigation and where much of the irrigation is accomplished by toilsome hand labor. Finally, in the minds of investigators, transpiration has frequently been associated with assimilation. The water requirement of agricultural crops has usually been stated in a ratio of the quantity of water tran- spired to dry substance produced. As a rule, this ratio has been considered merely as a convenient empirical expression of the water-utilization of plants; but some writers have assumed a closer relation and have postulated a direct influence of transpiration on production, or conversely. Therefore, it is of interest to determine to what extent the conditions induced by shade, either directly or through their influence on transpiration, affect production. For these reasons, the work described in the following pages was undertaken at the Cuban Agricultural Experiment Station at Santiago de las Vegas during the season of 1908-1909. For con- stant and ready aid in carrying out the exacting work required for this investigation, I am much indebted to ENRIQUE IBANEZ and AvcuSTIN GaRCIA, at that time my assistants at the station. Environment GENERAL STATEMENT For the purpose of these experiments, six tobacco plants were grown in the open ground, and six under cheese-cloth shade in 4 manner described later. The cheese-cloth was of the kind generally used in Cuba and elsewhere for shading tobacco (fig. 1). During the middle of the day, when the sun’s rays are nearly perpendicular, this cloth casts a barely perceptible shadow, which, however, 'S more noticeable early in the morning or late in the afternoon. In . FITTBOGEN indeed grew to maturity some plants of oats in a greenhous¢ and others in the open. He regarded the loss of light due to its passage through ee glass as one of the factors tending to lower the transpiration of the plants. This experiment, however, can hardly be classed as a study of the effect of shading 08 transpiration. Fitrsocen, J., Uber Wasserverdunstung der Haferpflanze "0 2 verschiedenen Warme-, Licht-, und Luftfeuchtigkeits-Verhiltnissen. Landw. J 3:141-146. 1874.” 1914] HASSELBRING—EFFECT OF SHADING 259 order to determine the effect of the cheese-cloth on the environment of the plants, measurements were made during the course of the experiments of the various environmental factors both under the ems Ske op oe OS ew od a pe am Tt} me tie 5), ese eee aeall See ereaa ao a a Lod vane a ae aes PT ded Fic. 1.—Photograph of the cheese-cloth used in the experiments; natural size cheese-cloth and in the open. The results of these measurements are given in the following paragraphs. LIGHT The light intensity under the two conditions was measured by the Photometric method. The method in general was that de- scribed by Wiesner? and used by him in his extensive researches on the light relations of plants. However, owing to the difficulty of making a sensitive paper which at some stage in the process of dark- ening would exactly match the normal tint kindly sent the writer by Professor W IESNER, a standard instrument, the Wynne exposure- meter, was used in these observations. The time of exposure was measured by means of a stop-watch. The applicability of this method, as well as its shortcomings, have been fully discussed by Wiesner and others, and recently Lrvuvcston‘ has subjected * Wiesner, J., Der Lichtgenuss der Pflanzen. pp. 10-33. 1907. ' Livixcston, loc. cit. 260 BOTANICAL GAZETTE [APRIL to a critical comparison this and other methods of measurement of solar energy. These discussions need not be repeated here. In spite of the shortcomings of this method, it has the advantage of being capable of easy manipulation and gives sufficiently correct results for a comparison of relative light values under the cheese- cloth shade and in the open. The observations were taken on December 17, December 23, and January 25. December 12 and January 25 were bright days with only a few hazy clouds, which are usual in Cuba toward the middle of the day. December 23 was cloudy, so that all the light © on that day was diffuse. On the first day, December 12, ten obser- vations were taken usually at each hour period for each kind of light under each condition, but on account of the length of time required to make that number of observations and the change of light mean- while, only five observations were taken at each reading on te other days. As a rule, the observations were taken alternately within and without the tent. Since the personal equation in the judgment of color is likely to play an important part in determining the time required for the sensitive paper to reach a standard tint, the probable error of the average was calculated for each set of observations, except some taken early or late in the day, when, on account of the weakness of the light, it was not possible in some cases to take more than one or two observations. An examination of the probable errors given with the column of averages shows that it is not of undue magnitude. It may also be stated that the ten or five observations from which the average is made up showed a very close agreement, usually within a fraction of a second of each other except when the exposures were very long, that is, 3° seconds or more, although, as has been stated, the observations were taken alternately in the two stations in such a way that the observer wa> not influenced by the previous observation and record. From the observations thus made each hour in each station, the average time of exposure was calculated. These averages with their probable errors are given in table I. The light intensity is of course proportional to the reciprocal of the time of exposure. These reciprocals were obtained, therefore, but in order to reduce the figures of each day to relative values, the 1914] HASSELBRING—EFFECT OF SHADING 261 highest light intensity for each day was assigned the value of 10, and the other values were reduced to the same basis. These figures are given in table II. The relative light values for any one day, therefore, are all directly comparable, but the figures for one TABLE I AVERAGE LENGTHS (IN SECONDS) OF EXPOSURES MADE IN DETERMINING LIGHT VALUES OPEN SHADE Thee Total light Diffuse light Total light Diffuse light Dece 12 8:15- 8:30 A.M 5.330.112 10.66+0.10 8.72+0.10 12.13 0.25 9:15- 9:30 A.M 3-560.07 6.900. 13 6.22+0.11 9.72+0.13 : 10:00-10:15 A.M 2.92+0.09 7.58+0.18 4.360. 10 7.31+0.11 TEOO-11:15 AM..| 2.23-0.05 8.26+0.13 3.29+0.02 9.32=0.12 12;30- 1:00 P.M..| 2.32+0.06 7.55#0.13 3.06+0.11 9.29+0.10 1:30- 2:00 PM..| 3.58+0.07 9.67+0.10 5.13+0.07 | 10.48+0.21 2330- 3:00 P.M. 5.16+0.11 | 12.30+0.23 7,140.19 |. 10.33£0.12 3:30" 4:00 PM..| 8.70+0.18 | 17.26#0.18 | 11.340.12 | 15.480.34 4°45- §:15 P.M..| 24.32+0.95 | 60. T3G. GO ia She es December 23 © ees ers ta, $2.07%6.80 Tier a 56.33+1.03 ee 1G, 0820.80 [77.33 a ee 15.68+0.57 ee 1.406. 82-1 9.23+0.49 Ge, ot... 7 OW b fond 3 SEN REE Res SPA 12.52+0.12 i cg ee ee O.4OS6 48 be ee 8.80+0.50 Me tS. te. 16. C6e635 0 Tae 13.660. 18 MI, foe oe an 1. ee ee eee cr 7.84+=0.08 ARE ee ee G. 440696 8 Se. ses 8.44+0.08 | SSRs See ie te 6.964%0:08 410 2S eae: 10.56+0.11 | co th SSS ee eet $4.1000.56 102 eS 21.400. 34 Oy cs: Sy comes. 661s ees 94.00+0.67 grpond 25 -OO A.M : ee ee BOCs} 2. 20 bi oe ee Tt. 0074.05 [snc ass vere POO AM af Sales ess take io deren caret oe besa ee. 3.60+0.07 8.48+0.08 7,120.12 | 11.20+0.10 Shain ole pe 3-00+0.06 | 10.32+0.14 6.32+0.10 | 11.60#0.20 eg te alge 2.340.09 6.880. 16 4.76+0.11 7.820.07 sch ie... 2.040.05 6.920. 16 3.60+0.08 8.16+0.08 oe Pees. 2.480.05 7.68+0.09 4.00+0.06 8.56+0.16 eM, 3.52+0.08 10.08+0.12 440.10 | I1.35#0.17 3:00 P.M Bese 5.600. 21 13.120. 29 8.120.090 14.680. 22 OoPm. 7-20+0.09 20.00+0.30 15.480.26 |. oe. ee Shimer gree day are not directly comparable with those of another day, since ®r each day a different number was taken as the unit. This system was adopted since it was not the purpose to compare the light values of the different days, but only those within the cheese- loth tent with those outside. : 262 BOTANICAL GAZETTE [APRIL From table II the following conclusions may be drawn: On the bright days (December 12 and January 25) the total light within the tent was 30-40 per cent, or about one-third, less than that with- TABLE II RELATIVE LIGHT VALUES UNDER CHEESE-CLOTH SHADE AND IN THE OPEN DIFFUSE ick Ge Total LIGHT DIFFUSE LIGHT RATIO Toray OBSERVATION Open Shade Open Shade Open Shade ber 12 8:15- 8:30AM..| 4.2 2.5 2.1 1.8 0.50 or Q:15- 9:30AM..} 6.3 3.6 3-2 a2 0.51 0.64 10:00-10:15A.M..| 7.6 ‘4 2.9 3.0 0.38 9.59 IT:OO-IT:15A.M..| 10.0 6.8 2:7 2.4 0.27 0.35 12:30- 1:00P.M..| 9.6 7.3 2.9 2.4 0.30 0-33 1:30- 2:00P.M..| 6.2 4.3 2.3 2.1 0.37 Oe 2:30- 3:00P.M. 4.3 3.1 1.8 2.2 0.42 seh 3:30- 4:00P.M.. a5 2.0 124 see 0.52 uch 4:45— 5:15 P.M.. 0.9 0.2 oy es Rage pre 0.445 Ee December 23 7 OO BAR Cerin re ee Pe ce eee 6 ro «ee Pet ee a pif)! Ri AE a Ob ed. ol oe 4.8 9.9 oe sees GOO BIE ee ea 7.9 A tee ers T8500 ROM ee ee 6.7 BY oo eo ELIOO AM ioe fies eee 7.6 Bis BROOM. hie oe se cea , 4.8 G.8 < foc ccis eee SOO PMS oe ey ee 10.0 6:6 45. ee ROOM eel oe 8.1 620 cheikh eee SOG Pa Sie rad em nts 7.4 AiO ist BOO Ee Eee oooh aie ca yk 326 Pee Gees Creer Ss ass: SOG BoM ec pe ene ie So 0.6 OF eh eee ee January 25 7:00 AM. cs 0.3 OF aes Pras are ae Pe eel fe on ue 8:60 AM oes 2.3 1 re Seth, Parana eprreger tial We ar epers rary Pape Maca fel iia ah HOC AM 2... 5.7 2.9 2.4 1.8 0.42 0.62 IO;OO AM. ys... 6.8 5.2 2.0 1.8 0.29 0.50 SEOG AM. 22. 8.7 4.3 3.0 2.6 0.34 re" 2 OO 10.0 Cy 2.9 2.5 0.29 _ TOO PM a c. 8.2 se a7 2.4 0.33 ote 2:00 FE. ac: 5.8 2 2.0 1.8 0.34 se $700 $48 3.6 2.5 1.6 1.4 0.44 0.56 2:00PM. oo 2.8 ae Ri as oes @.90 [rexere [J out, but the diffuse light showed very little difference in the two stations on those days. On December 23, however, when there was no bright sun, the total light in the tent (all diffuse) was reduced by about one-third. On the bright days the ratio of diffuse light to total light was much higher in the tent than in the open. € 1914] HASSELBRING—EFFECT OF SHADING 263 effect of the cheese-cloth tent, therefore, appears to be not only. to reduce the total amount of light available to the plants, but also to transform a large proportion of the direct light into diffuse light. The plants growing within the tent have available for photo- synthesis less total light than the plants growing outside, but a larger proportion of this light is diffuse. TEMPERATURE The temperatures in each of the two stations were recorded by Fries thermographs placed in shelters so constructed, with double roof and open sides, as to protect the instruments from the direct Tays of the sun and from rain without hindering the free circulation of air. The thermographs had been carefully adjusted during a few weeks’ trial previous to the beginning of the experiments. After having been placed in the field, they were daily compared with Standard thermometers whose bulbs hung near the bellows of the instruments. The thermographs agreed very closely with the thermometers throughout the experiment, and required very little further adjustment. The average daily temperatures during the course of the experi- ment were obtained by integrating the records for each day with a Planimeter. The results thus obtained, together with the differ- ences between the daily average in the tent and in the open, are given in table III. The records are given in Fahrenheit degrees since the instruments recorded in that scale, but the values have also been calculated in Centigrade degrees, which are given in the last two columns. Table III shows that there was no marked difference between the temperature within the tent and that outside. The difference Was usually less than one degree. Moreover, it was sometimes Positive and sometimes negative. ‘The sum of the differences for the total period is only 7°67 F. The average daily excess of the perature outside the tent over that inside was therefore approxi- mately of14. This is contrary to the results of SrEwART,’ who found that in the Connecticut Valley the average daily temperature ‘ *Stewarr, J. B., The effects of shading on soil conditions. U.S. Dept. Agric., “reau of Soils, Bull. 39. 1907. 264 BOTANICAL GAZETTE [APRIL e TABLE III AVERAGE DAILY TEMPERATURE ar) TEMPERATURE ais bon 3 AHRENHEIT ENTIGRADE For peg hper: ae : : DIFFERENCE Open Shade Open Shade December’ 4... =: Pees ote ret ot ee 22.36) si ee * Le 69.54 70.91 +1.37 20.86 21.62 a ores, vt. 3s 76.14 +0.79 24.08 24.52 F Puss. 74.54 73-93 sa, 23.63 23.20 Bis; 68.52 69.0 +o.51 20.29 20.57 . OSES ee 71.67 7E.12 —0.55 22.04 21.73 £ 2s Ae 69.68 68.77 —o.9gI 20.93 20.43 bs cs Beer 64.86 61.90 —2.9 18.26 16.61 wee ee 62.86 63.56 +0.70 17.14 17.53 = my 67.03 66.55 —o 19.46 19.19 . be angie, 64.46 64.86 +0.40 18.03 18.25 ‘ re 67.02 68.13 +1.11 19.46 20.07 € 1655553 66.85 67.74 +0.89 19.36 19.85 . in 67.26 68.53 +1.27 19.59 20.29 . { aeahe 64.68 67.40 +2.72 18.16 19.67 ¢ to 69.82 +o0.82 20.56 21.01 - 2 ist eee 71.17 72.05 +0.88 21.76 22.25 . ae. 67.75 67.60 ° 19.86 19.78 : . 68 70.55 +1.65 20.50 21.42 « ee 67.06 67.43 +0.37 19.48 19.68 : ee tage ae 65.04 65.10 +0.06 18.36 18.39 e ae 65.34 64.95 —0.39 18.52 18.30 260 ey 63.42 63.54 +0.12 17.46 17.52 . cy See ae 58.30 58.45 +o.15 14.61 14.69 . rae 65.76 65.25 —o.51 18.76 18.47 . ee 67.94 67.62 —0.32 19.97 19-79 2 co Specie 72.85 7O.51 —2.34 22.69 21.39 . Lo ae ee 72.00 70.86 —1I.14 22,22 21.59 jeaeaay | A 68 68.04 —1.64 20.93 20.02 . Foes 68. 23 68.01 —0.22 20-43 20.01 vs ee ve ee 71.02 —1.11 22.29 21.68 : ae 73.81 72.81 —1.00 23.23 22.67 : €.55 4 72.28 71.78 —o.50 22.38 22.10 : C7 2 68.47 —o.15 20.34 20.26 3 Fie: 63.29 62.17 —1.12 17.38 16.76 : S55: 62.69 61.309 —1.30 17.05 16.33 “ Q.. q 65.28 —1.39 19.26 18.49 860.0%. 66.58 66.64 +0.06 19.21 19.24 . i. 65.07 64.80 —0.27 18.37 18.22 . 1202, 66.89 66.60 —0.29 19.38 19.22 : 8, Sa 65.69 65.14 —0.55 18.72 18.41 : FA oe 71.80 69.51 —2.29 22.11 20.84 * : gee 67.50 65.73 —1.77 19.72 18.74 2 10s 67.42 67.0 —0.33 19.68 19-49 ~ pe 65.33 64.13 —1.20 18.52 17.85 i... 63.84 63.45 —0.39 17.69 17-47 . 10s 65.58 67. +1.42 18.66 19.44 . oS : 66.40 66.37 —0.03 19.11 19.09 ee 65.96 65.18 =o 78 18.87 17.88 1914] | HASSELBRING—EFFECT OF SHADING 265 TABLE I1I—Continued MEAN TEMPERATURE MEAN TEMPERATURE FoR 24 HOURS ENDING (FAHRENHEIT) (CENTIGRADE) AT 4 P.M. DIFFERENCE Open Shade Open Shade and that these vessels are wider in deciduous than in evergreen species, even though the latter may grow in moist Florida, as 1S the case with Q. virginiana. The subjoined statistics suggest strongly 1914] white oaks; which is subtropical. GROOM—TRACHEID-CALIBER TABLE IV AMERICAN DECIDUOUS SPECIES OF QUERCUS B, black oaks; all are warm temperate excepting Q. lobata, WIDTH OF WIDEST SPRING VESSELS Atlantic Pacific HaBITAT Q. Garryana....|.. fe opata:.......|.. Q. obtusiloba.. . . Q. macrocarpa.. . Q. Macdonaldi Q. californica. As 0.362 ©.372 ©.412 0,412 0.419 a oe ee eele ree ne ee ee Dry habitat; Vancouver to Califor- dry gravelly also between sh hence tending to be sub-evergreen. ry sandy — or on har e dryness and bb ie ee ies dere ;Cape ei o Florida, Mississippi, "eras, is’) ° mr Variable as ae a showing power of endurin hwest regi which is wide, oo from — Scotia and Ontario to Min- , Texas, etc. Islands off California egon, coast ranges of Califor- 000 ft. in western slopes - Mississippi, T etc. Good wet — (aot ’ swamp) at the edges of s margins ns of rivers; Cinade * Missouri, Vir- ginia, Arkan 304 BOTANICAL GAZETTE [APRIL TABLE IV—Continued WIDTH OF WIDEST SPRING VESSELS Atlantic Pacific HABITAT WwW B WwW B Q. aquatica.....|...... OMe as Salen oa. Sandy borders of swamps; Delaware to Florida, Gulf States, Texas, ss Oklahoma, etc. (\ Mulienbensi:| 6.444)... fo ok Variable habitat; dry hills to deep > rich bottom lands and rocky banks of streams; Ontario to Columbia, N. Louisiana, Texas, etc. : 8 a Ae nate oe Cie! eed ies ROS taes i eeareae Optimum soil is fresh (rather moist) loam in un i sa to gravelly ridges; Ontario to N. : Flori innesota, Texas, etc. ©. bieotor: (3.3. rag Ei Reema ba a sty Sac tie aaa Borders ot streams and swamps; On- io ia and W. Mis- souri; does not extend so far south as Q. alba. Ages ven eee Borders of swamps and streams; Delaware to Florida, Gulf States, Kentucky, etc. Q. Michauxii....| 0.587]...... that in the deciduous species width of spring vessel is at least largely determined by systematic affinity and by available water supply; the spring vessels being narrower in species belonging to physically or physiologically drier places, and for the same type of habitat being narrower in black oaks than in white oaks. The points of significance in connection with the deciduous oaks are: 1. Of the six species with narrowest spring vessels (0.338 0.378 uw), four are Pacific species and characterized by drier climate than the Atlantic species. Among the four Pacific species, the oné with the narrowest vessels is the one whose soil is definitely stated to be dry gravel. The second is subtropical in the region of ever- green species, and itself approaches the evergreen stage. cL habitat (apart from the Pacific climate). Of the two Atlantic species, one occupies an edaphically dry habitat, while the other, though variable as regards habitat, shows a power of living 0? at least rather dry sites. 1914] GROOM—TRACHEID-CALIBER 305 2. Considering the Atlantic species, and taking separately the two series representing respectively the white oaks and black oaks, the former of these begins with the two species just referred to, continues with two species of variable habitat as regards soil, passes to one in which the optimum soil is rather moist but varies, and concludes with two species confined to thoroughly moist soil. The last of these also occurs in the region where the American pines exhibit the greatest caliber of tracheids, namely, Florida and the Gulf States. The series of Atlantic black oaks commences with wider vessels than the series of white oaks. The first species shows no special choice of soil, but can grow farther north than any other American warm temperate species; the next two species clearly show prefer- ence for dry situations, or at least a capacity for thriving on dry -Sravels; the series, like that of the Atlantic white oaks, concludes with two species confined to thoroughly moist soil on the borders of SWamps and rivers. Summary 1. There is considerable evidence that the width of the spring tracheids in evergreen Coniferae is largely decided by two factors, systematic affinity and available water supply. So far as the latter is concerned, the spring tracheids are generally narrowest in species of xerophilous habitat. 2. In American species of Pinus belonging to section I (Haplo- xylon), variation in the width of the spring tracheids runs quite Parallel with difference of systematic affinity and of available water Supply (including influences promoting transpiration). Thus the ‘ist step in the evolution of this section of Pinus would appear to have been a division into a more xerophilous type (ancestral Para- CEMBRA), and a less xerophilous type (ancestral CeMBRA), and each of these subsections would appear to have undergone similar divi- Sion into more or less xerophilous groups, that is, into PARRYA and Batrourta, also Ev-cempra and Strosus. The two East Indian Species, P. Gerardiana and P. excelsa, structurally accord With this theory. : 3- Among American species of Pinus belonging to section i (Diploxylon , those with narrow spring tracheids are more xerophi- 306 BOTANICAL GAZETTE {APRIL lous in distribution, while those with the widest tracheids belong to a subtropical or tropical moist climate. Though in general this section of Pinus supports the theory given in paragraph 1, there are in it certain species in which width of tracheid does not appear to correspond with the supply of available water. Such discrep- ancies, whether real or only apparent, may be due to one or more of the intervening causes mentioned in paragraph 6. 4. Species of other North American genera of evergreen Conif- erae show differences in the width of spring tracheids that may possibly be partly due to differences in affinity; as species of the same habitat, but belonging to different genera, may differ con- siderably in tracheid width, or, on the other hand, may approximate to agreement. Some of these genera, namely, Torreya, Chamae- cyparis, Sequoia, and Juniperus, support the view that the width of the spring tracheid is correlated with available water supply; somewhat favoring the view are Cupressus and Picea; indifferent in indication are Abies and Larix. 5. The theory here propounded derives support from measure- ments of the width of the spring vessels of American deciduous species of Quercus. For narrowness and wideness of spring vessels in the main are respectively associated with scantiness and abun- dance of water supply. But in the same kind of habitat the decidu- ous black oaks would seem to have narrower spring vessels than are possessed by the deciduous white oaks. 6. Though the evidence as a whole strongly favors the theory here propounded, much fuller information is necessary before 4 safe conclusion may be drawn. Hence this inquiry and the sug- gestions here given must be regarded as tentative and issued in the hope of stimulating inquiry in regard to factors that may interven®, such for instance as the following: climate (including evaporation power), exact soil water-content, level of water-table, etc., that form the environment of the different species of conifers; ls0, depth of root, duration of foliage and size of aggregate leaf surface, rate of transpiration, width of sap wood, etc., in the different species; also, variations within one and the same species in Tes# to the features just mentioned, as well as in the width of the spring tracheids, in different habitats. IMPERIAL COLLEGE Lonpon 1914] GROOM—TRACHEID-CALIBER 307 LITERATURE CITED 1. Groom, Percy, Remarks on the oecology of Coniferae. Ann. Botany 24: 241-269. IQIo. 2 , and Rusuton, W., The structure of the wood of East Indian species of Pinus. Jour. Linn. Soc. London Bot. 41:457-490. 1913. - Mayr, H., Die Waldungen von Nord-Amerika. 1890. . PENHALLOW, D. T., A manual of the North American Gymnosperms. 1907. 5. SARGENT, C. S., Manual of the trees of North America. London. 1905. > w NOTE ON THE ASCOSPORIC CONDITION OF THE GENUS ASCHERSONIA MONTAGNE* ROLAND THAXTER (WITH SEVEN FIGURES) The genus Aschersonia includes a group of entomogenous fungi which have hitherto found a place among the Sphaeropsideae, . since, as far as I am aware, no ascosporic condition has as yet been observed in connection with any of them. Although a great majority of the forty or more species which have been described, for the most part from the tropics, are said to occur on the leaves, etc., of various hosts. among the vascular plants, there can be no question in the mind of anyone who has had an opportunity to examine them in a fresh condition that they are strictly entomoge- nous, like the species of the genus Hypocrella, which have a simi- lar habitat on various types of scale insects; and, as is well known, two species of the genus have been successfully employed in Florida against certain scales attacking Citrus. As in the case of other entomogenous fungi, the character of the host plant on which species of Aschersonia have been reported is thus a matter of very little importance, except in so far as it may suggest the nature of the scale which has been attacked while feeding on it. Although it Is not improbable that some of the species are not restricted to closely similar hosts, there are indications that others are more definitely conditioned in this respect, and an examination of this matter from the entomological side is much to be desired. Unfor- tunately, very little information is available in this connection, and the actual hosts of the too numerous and ill defined species, a maJol ity of which have been described within the past fifteen yea™ are, with a very few exceptions, quite unknown. In view of the general characteristics of Aschersonia, it has been naturally assumed that the ascosporic form, if it exists, would find a place among the Hypocreaceae, the often bright thous very variable and inconstant colors and comparatively soft co” > if Po, a » f. a rs rite aes se . etr. 1 Tiniversityv. LXIl. 7 Botanical Gazette, vol. 37] [308 1914] THAXTER—ASCHERSONIA 309 sistency of the different species pointing to this conclusion. It has been suggested that they might be imperfect conditions of species of the ascomycetous genus Hypocrella, with which, owing to their similar mode of life, they are apt to be associated; and this sug- gestion is still further supported by the fact that when a flat hemi- spherical type of Aschersonia has become blackened by age and exposure, or colored by the sooty disintegrated material of accom- panying Capnodia, which grow on the excreta of various hemip- terous insects, it is often difficult to distinguish the two by their §t0ss appearance. Definite information in regard to this con- nection, however, has hitherto been lacking, and, as already men- tioned, I have found no record of observations which might throw light upon it. P. Hennincs in the ASCHERSON Festschrift, where he discusses the validity of the generic name and certain other matters, states that he was informed by ZIMMERMAN, whose con- tributions to the knowledge of Javan entomogenous fungi are well known, that although he sought for them with care he never €ncountered any individuals which showed indications of an ascosporic fructification. During the past year (1912~1913) I had an opportunity to spend Some months on the islands of Grenada and Trinidad, and having the matter in mind made a special effort to discover this proble- matical ascosporic form. In the locality where I remained during Practically my whole stay in Grenada, Aschersoniae were by no means numerous, and only three species were met with. These forms, moreover, were comparatively rare, although one of them, the well known and characteristic though very variable A. turbi- "ata, was found several times. A few specimens of this species In the original gathering from a certain locality showed, when carefully examined, certain not very conspicuous but suspicious looking pustules, containing cavities unlike those of the pycnidia, which appeared to be young perithecia, and by a systematic search in the same spot I was able to obtain numerous specimens bearing the perfect form fully and characteristically developed. Unluckily, the majority of these specimens were accidentally destroyed by fire, together with many other mycologic treasures, but a sufficient humber were saved, both dry and in alcohol. 310 BOTANICAL GAZETTE {APRIL In Trinidad, where the flora as well as the insect fauna is far more varied, Aschersoniae were numerous, and in most instances it was possible to gather abundant material of each species. These gatherings in the case of four or five species usually included the ascosporic condition, which was often abundant, and, as in the case of A. téurbinata, occurred either by itself or associated on the same stroma with the pycnidial form; so that there could be no question as to the actual connection of the two conditions. As far as could be determined, the position of growth, whether on the upper or lower side of a leaf for example, in shady and moist or in drier and more open situations, has little if any influence on the develop- ment of the perfect condition. In some instances it appeared to follow the pycnidia in older specimens, while in others it was as evidently primary in its development and unaccompanied by pycnidia. The general character and appearance of the perfect condition recall those of some species of the genus Cordyceps, to which Ascher- sonia is evidently closely related; and, as in this instance, the association of the perithecia and the development of perithecial stromata varies in different cases. In some instances the peti- thecia may be closely and definitely grouped in a compact and prominent stromatic outgrowth from the general stroma, which may be otherwise sterile, while in many the whole stromatic mass may become transformed into a pulvinate aggregation of densely crowded perithecia. The general appearance of such forms, which in one instance may be definitely stalked, is not unlike that of some species of Cordyceps or Hypomyces. In other cases the perithecia may be irregularly scattered in a somewhat looser stroma, and might at first be mistaken for the common Cordyceps (Torrubiella) arachnophila, which is often found on leaves with or without 1ts imperfect or Isaria (Gibellula) condition. But in this instance, although the host may be as completely obliterated as it is by Aschersoniae, the perithecia are always much more prominent. Having assembled a considerable number of Aschersoniae from various sources, it was first my intention to attempt 4 revision of the genus, but an examination of the literature and such mater as is available has made it evident that this is hardly possible at 1914] THAXTER—ASCHERSONIA 311 the moment, the great variability of the individual species as regards habit, size, and color, the usually insignificant differences in their spores as well as the absence of any information as to the nature of their true hosts, except in a very few cases, combining to make their systematic study a matter of great difficulty. It has seemed desirable, therefore, in the present connection to attempt no more than a brief preliminary note on the ascosporic stage of A. turbinata, a species which, although it is extremely variable in habit, size, and color, is in its typical form quite unmis- takable. Although the perithecial stromata of Aschersonia turbinata are less highly specialized than they are in some of the species, the perithecia are usually aggregated in more or less distinct pustules which, more frequently in this than in others, seem to arise after the pycnidial form has practically ceased its activities. Often, however, the whole stroma is perithecigerous, and no pycnidia precede or accompany them. In some cases these perithecial groups are very small, as in fig. 1, where less than a dozen have been pro- duced from an old stroma bearing two well developed pycnidial cups. In fig. 2 a smaller but similar cup is associated with a much more definitely developed perithecial pustule, and fig. 4 shows in section a similar condition. In fig. 3 almost all of the original stroma is perithecigerous, a small pycnidial cup being present at the side, while the perithecia are more scattered. The section of such a specimen (fig. 4) shows a continuous homogeneous stroma, com- posed in all parts of absolutely identical, closely and intricately interwoven, thick-walled, undifferentiated hyphae; so that, were it not otherwise evident, there can be no question that the peri- thecia observed are those of the Aschersonia, and not of some other ‘ngus parasitic on its stroma. It may here be mentioned, how- ever, that several such parasites have been observed, although their characteristics are quite different. € perithecial cavities, as shown in fig. 4 at right, are almost Completely imbedded in this stroma. They are bottle-shaped, with a relatively narrow and well defined neck, about 440X150 p, and are surrounded by a more dense, thin perithecial wall, the Substance of which is like the similar but broader layer which sur- 312 BOTANICAL GAZETTE [APRIL rounds the neck and forms the bulk of a definite though not very prominent papilla which marks the position of the perithecium externally, and is perforated by the ostiole. The asci (fig. 5), which arise from a slight cushion at the base of the perithecial cavity, are about 210X 7-8 yu, rather slender at maturity, tapering slightly to the peculiarly differentiated apex, which is modified (fig. 6) in a fashion exactly resembling that seen in the asci of Cordyceps and its allies. As the asci mature, the stalk becomes more elongate and slender than is represented in fig. 5, and the — Fics. 1-7.—Aschersonia turbinata Berk.: figs. 1-3, three stromata bearing PY“ nidial cups and perithecial pustules, X3 ascus not fully mature (Zeiss D+4); fig. 6, tip of a nearly mature ascus sh ' segmented spores, and fig. 7, separated spore-segments; both Leitz water im.+125 figs. 4-7 are reduced to one-half. eight filamentous spores, which are at first cylindrical and contin- uous, are later divided by septa as in Cordyceps. The segments thus formed eventually separating from one another, the ascus becomes filled with countless spores, rodlike in form, about 10-12 X2-2.5 u, with rounded ends (fig. 7). The spores and their seg- ments are conspicuously vacuolate, so that they present 4 banded appearance which gives them a distinct individuality. The characters briefly enumerated above apply in general to the perfect conditions of the remaining species in which they have 1914] THAXTER—ASCHERSONIA 313 been observed, the specific variations, in so far as I have examined them, consisting in minor differences relating to the distribution, form, and size of the perithecia, the size of the spore-segments, ' etc., but since, for the reasons above stated, it seems almost impos- sible at the moment to determine them accurately, any further account of them must be deferred. HARVARD UNIVERSITY MORPHOLOGICAL INSTABILITY, ESPECIALLY IN PINUS RADIATA . Francis E. LLoyp : (WITH TWO FIGURES AND PLATE XIV) The various behaviors of the vegetative and reproductive shoots in the Coniferae have for many years been the objects of extended observation and experiment, and these have been the basis of a massive literature. From this we may derive no mean conception of the amount of morphological instability which characterizes that genus which, in some regards at least, is the most highly specialized of all, namely Pinus. Of the conditions which discover such instability, injury has been the most efficient, the resulting unusual developments being said to be due to disturbed nutrition, especially over-nutrition. Precisely what is meant by this is not and cannot at present be stated, so that any light which experiment or the — diversity of behavior in nature may afford us should be welcomed, especially if it may lead to a more specific indication of the most potent of the causes which must always be at play. Evidence of such specific value is given us by the Monterey pine (Pinus radiata), a species as definitely restricted to a small area as the famous Monterey cypress (Cupressus macrocarpa), & e0- graphical neighbor. The center of this area is, as nearly as may be, at Carmel-by-the-Sea, where is stationed a laboratory of the Carnegie Institution of Washington. The detailed descriptions of California trees in Jepson’s Silva of California render minutiae unnecessary, though it may be noted in passing that among the teratological observations no mention is made in this work of the peculiarities to be noted below. Carmel is situated in a forest of Pinus radiata, not, howevel, to the advantage of the tree. It is becoming more and more ae come by borers and fungi. It is, in any event, a short-lived tree ° small dimensions but very rapid growth, a fact of importance . the present connection. It grows readily under cultivation, a6 Botanical Gazette, vol. 57] [34 1914] LLOYD—PINUS RADIATA 315 is very commonly seen in gardens, having either started by chance or by being planted. It is even used as a hedge plant, though of indifferent value for the purpose. But this circumstance leads often to the trimming of young trees, and so enables us to judge of the relative effect of traumatic stimulus as compared with another, namely, the amount of soil water, in producing unusual responses. It must be prefaced that the amount of soil water in the normal habitat of this pine runs down very markedly during the long grow- ing season, in spite of the moisture-laden atmosphere. Exact measurements are lacking, but the fact is sufficiently evident from the behavior of the vegetation in general, which becomes during the summer months of a distinctly xerophytic character. To this condition is due the gradual reduction in length of the fascicled leaves toward the apex of the season’s growth, giving to the foliage of the leaders a cone-on-cone profile. Purixrps' has observed the same fact in Pinus cembroides Zucc., the Mexican pifion, in the mountains of southern Arizona, in a habitat which may, as regards soil moisture at any rate, be compared pretty closely with Carmel. When grown in gardens, however, it generally happens that a Steater abundance of water is provided, toward which a marked Tesponse is shown, both in amount of growth and in abnormal behavior. This is most obvious in an open spot used as an experi- mental garden within the grounds of the Carnegie Laboratory. Here the soil is kept abundantly supplied with water from springs, and here grows a cluster of young trees with heights ranging up to 30 feet or over. Aside from the generally well developed character of these, they all have fascicles which in the majority of cases proliferate. So numerous are the resulting short shoots that the Tanches become densely clothed, enough so as to quite hide the Parent shoot itself from view when looked at from above. Interest attaches to the phenomenon less because of the morpho- logical fact, since it has long been known that pine fascicles do sometimes proliferate? than because of their abundance and the * Plant World 14:66. ro1t. * For the literature on this see Tomson, R. B., The spur shoots of the pines (to @ppear in the next issue of this journal), the manuscript of which the author has kindly allowed me to see. - 316 BOTANICAL GAZETTE [APRIL regularity and constancy of their production. They appear, not, as might be expected, when the fascicles are young, but in those three or four years old especially. Unlike the lateral shoots of the whorls of branches, they are always negatively geotropic. This feature is brought out sharply in pl. XIV, B, which shows a length of a three-year old branch between whorls. The fact that fascicles as old as three or four years can renew their youth is worth notice. Those of Pinus Taeda in Alabama have been found to proliferate after two years, having been stimulated to grow from injury by cattle. This was in the cases of a couple of small trees which were six or eight years old. So far as I have been able to observe, in no instances do the abnormally developed spur shoots become pet- manent branches in Pinus radiata, although that there is evidently nothing in their nature to prevent furthet development appears from the fact that such is the case in Pinus Taeda (fig. 2, B). 1 have thought that the rapid rate of growth of the parent branch and the smallness of the spur shoots rendered successful histological articulation difficult, discrepancies which would be reduced if the parent branch is small to begin with, and of not rapid growth, as is true of P. Taeda. Another example, and a still more striking one, I found at Carmel in the yard of Mr. Stevin, who kindly made a photograph forme. Except below, it was entirely without whorls, though . few extra-verticillate but ill-developed branches had grown. This abortion of whorls is quite common in this tree, but has. been seen in other Coniferae (Pumturs, loc. cit.). The tree was growing quite near a cesspool. As the photograph shows, the whole of the chief stem (save for a small stretch) was densely clothed with foliage, due to the proliferation of nearly every fascicle, so that a fox-tail effect was produced. In the lower part of the stem, at the level of the bottom of the photograph, the spur shoots were dying and dropping off. Above they were growing, and the longest had attained a length of several centimeters. It was evident, however, that they were not able to become permanent in character, and there was no evidence that any of the branches had originated from fascicles. I found no other such examples. Occasionally in small trees 1914] LLOYD—PINUS RADIATA 317 which had been trimmed I saw a tendency for the fascicles to pro- liferate, but it was quite evident that pruning is by no means as efficient a factor as water supply. At the same time, we are bound to note that precisely where such a supply is abundant, and, in a remarkable case shown in fig. 1, where nitrogen in some form must have been quite plentiful, the development of verticillate branches was arrested. Other cases of absence of whorls were noted at Car- mel, but only in gardens, though we know them to occur in nature Fic. 1.—Proliferated spur shoots of Pinus radiata: A, the shoot so formed Produced fascicles at once from the axils of the fascicled leaves of the spur shoot; B, hypertrophied scale leaves produced on the proliferating axis. in other species. It is evident, however, that it is not due to less favorable soil conditions even here, since Parties (Joc. cit.) notes that arrest of whorl development occurred in Abies on moist, rich Sitesin Arizona. One may conceive, furthermore, that a very rapid and energetic development of a chief shoot, especially in one in which the lateral shoots are not even laid down during the earlier Part of period of growth, might be held responsible for failure to Produce the usually formed lateral shoots. 318 BOTANICAL GAZETTE [APRIL Analogy in support of this view is not wanting, in general sup- port of which may be cited also the apparently rather ready pro- duction of proliferations from spur shoots, with or without injury, in pine seedlings found. by THomson. These seedlings grew in nurseries, probably under unusually favorable conditions for this Fic. 2.—Proliferated spur shoots of Pinus Taeda: A, development of the 40 below the whorl of fascicled leaves; B, a permanent branch formed. by proliferation. reason, especially as regards water supply. The likelihood that the spur shoots of mature trees do not proliferate, or if so more rarely than those of young trees or seedlings, is little lessened by my observations of Pinus radiata, since the trees were all young, or at any rate were not mature. BOTANICAL GAZETTE, LVII PLATE XIV a . LLOYD on PINUS RADIATA 1914] LLOYD—PINUS RADIATA 319 The character of the shoot produced by proliferation of the fascicular bud is worth further notice. As seen by the text figures, the leaves succeeding immediately on the fascicled leaves may be either true scale leaves (fig. 2, A and B), or the same hypertrophied (fig. 1, B), and hence of juvenile character; or again, new fascicles may be produced at once in the axils of the three leaves of the parent fascicle (fig. 1, A), thus showing that fascicled leaves may subtend axillary buds. Far more rare than any of the preceding is the elongation of the axis of the spur shoot below the fascicled leaves instead of that above, as I found to occur in P. Taeda after injury. In such cases the leaves of the fasciculate whorl (fig. 2, A) do not attain their normal shape and dimensions, but are wider at the base and taper somewhat toward the apex, thus approaching hypertrophied scale leaves in form. Here, therefore, we have arrested fasciculate leaves and over-developed scale leaves approach- ing a common type, which probably simulates the form of the scattered leaves of the progenitors of the pines. From the point of view of comparative morphology, it seems logical and in accordance with the facts to argue with THOMSON that the type of fasciculation seen in Pinus is a highly specialized condition, derived from a prototype in which the spur shoots are not limited in growth. As THomson, however, has taken up this question in the paper referred to, I leave it here. The degree of physiological plasticity displayed by various species of the genus, and especially the amount shown by particular ones, notably Pinus radiata, argues, in my own mind, for a comparatively recent origin of the kind of spur shoot characterizing it. The evidence above cited appears to favor the view that abundance of water is of prime importance in disturbing the ordinary equilibrium, and thus stimulating the proliferation of spur shoots. McGrz Unrversiry EXPLANATION OF PLATE XIV A, small tree of Pinus radiata from which are absent the normal whorls of branches; the dense fox-tail effect is due to very numerous proliferated Spur shoots; B, piece of a branch of another tree of the same species, showing the numerous proliferating spur shoots. LIFE HISTORY OF PORELLA PLATYPHYLLA CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 184 FLORENCE L. MANNING (WITH PLATES XV AND XVI) There was no definite knowledge of the morphology of Porella until CAMPBELL (3) published an account of the life history of P. Bolanderi in 1904. Under the name Madotheca, LE1tGEB (7) pub- lished a few figures of the apical situation. ENGLER and PRANTL (5) barely mention the group to which it belongs, and in their classification it receives the name Bellincinia (under the group Bellincinioideae). From 1904 to 1908, the literature is bare of any mention of Porella, that is, so far as its life history is concerned. In 1908, ANDREWs (1) accidentally discovered an abnormal situation in the archegonium, finding one with two axial rows, each contain- ing the same number of neck canal cells, and each with a ventral canal cell and an egg. He reported the fact without drawing any conclusion as to its probable meaning. All investigators who have worked with Porella agree in regarding it as of high rank among the acrogynous Jungermanniales. MATERIAL AND METHODS.—The material for the present inves- tigation was collected by Dr. W. J. G. LAnp, and some of it had been in the laboratory in a dried condition for several years. In order to revive it, it was soaked for 24 hours in water at a temperature of about 31° C. At the end of this period, it was as fresh as though it had never been dried; and the subsequent examination of the imbedded material showed that it had suffered no ill effects. This ability of liverworts to revive after a long period of desiccation has long been known. CAMPBELL (2) experimented with some Call fornian liverworts and found them able to recover after having been dried for months. No satisfactory explanation of this phenomenon has been given. GorBeEt (6) mentions the various devices of leafy liverworts for holding water for a long period, such as tubers, water sacs, etc., but this does not explain the power of revival after desiccation. Botanical Gazette, vol. 57] [320 1914] MANNING—PORELLA 321 After the material had been revived, the branches bearing sex organs and those bearing sporophytes were killed in 0.25 per cent chromo-acetic acid, imbedded, and cut in sections 6-8 thick. The stains used were safranin, gentian-violet, and orange G; - Safranin and anilin blue; and iron alum-hematoxylin. APICAL CELL AND VEGETATIVE BODY.—The apical cell is pyramidal, a type found throughout the Jungermanniales. By pyramidal is meant a cell whose cross-section is an isosceles triangle, and that has three cutting faces. Branches may arise from the latest segment of the cutting cell (fig. 1). The leafy body is dorsiventral and recumbent, with two dorsal leaves and one ventral leaf (amphigastrium). The dorsal leaves have ventral lobes, which give to the ventral surface the appear- ance of having three rows of leaves. The sex organs are borne on short lateral branches, those bear- ing archegonia being shorter than those bearing antheridia. The Sporophyte is surrounded by a cluster of broad leaves. ARCHEGONIUM (figs. 2-9).—The archegonium arises as a papil- late cell from the segment of the apical cell or from the apical cell itself. The first division is transverse ; the inner cell is the stalk cell, which does not divide until late in the development of the archegonium; the outer cell forms the archegonium. ‘The first division of this outer cell is vertical, followed by two more vertical walls in rapid succession, cutting off a central cell. Transverse divi- sion of the central cell results in the cap cell and the cell which pro- duces the axial row. Divisions of the peripheral cells form a jacket about the central cell and its progeny. The axial row comprises 4-6 neck canal cells in addition to the ventral canal cell and egg. : In the material studied, there was found an abnormal archego- mum such as ANDREWS (1) reported (fig. 9). Whether such an archegonium has any bearing upon the question of the origin of the archegonium or not remains to be seen. In any event, it would fit Well into the series of hypothetical sketches by Davis (4), connect- ing a gametangium (“plurilocular sporangium”’) of the brown algae With an archegonium of the liverworts. Miss Lyon (8) has described cases of archegonia among the pteridophytes with lateral multiplication of the cells of the axial row. gaz. BOTANICAL GAZETTE [APRIL - ANTHERIDIUM (figs. 15-27).—The antheridium arises as a papillate cell from a segment of the apical cell, but never from the apical cell itself. The first division is transverse, the inner cell being the stalk cell, and the outer cell producing the spermatoge- nous cells and the jacket. The next wall may divide the stalk cell transversely, or both stalk cell and outer cell may divide vertically. If the first division of the outer cell is not by a vertical wall, vertical walls appear in the next two divisions. Periclinal walls then differ- entiate jacket and spermatogenous tissue. The jacket becomes several cells thick by periclinal divisions, and by further divisions the spermatogenous tissue appears as blocklike masses of cells. At maturity, the stalk of the antheridium is long and slender, and uniformly two cells in thickness. SPOROPHYTE (figs. 1o-14).—Only mature stages of the sporo- phyte were represented in the material. Great variation in the shape of the foot was observed, from the club-shaped foot illustrated by CAMPBELL (3) to a more or less definite anchor-shaped foot. There is no elaterophore, or any grouping of the elaters, but @ general distribution of elaters through the capsule. I am indebted to Professor Joun M. Coutrer and to Dr. W. J. G. Lanp for advice and material during the progress of the investigation. UNIVERSITY OF CHICAGO LITERATURE CITED 1. ANDREWS, F. M., An abnormal Porella platyphylla. Bot. Gaz. 45*34° Jigs. 3. 1908. scm 2. CAMPBELL, D. H., Resistance to drought by liverworts. Torreya 4:0F°™ 1904. , Mosses and ferns. New York. 190 ‘ eas 'B. M., The origin of the kaon Ann. Botany 17:477-49?" eas ieee and Prantt, Die natiirlichen Pflanzenfamilien. 1895. GoEBEL, K., Organography of plants. Oxford. 1905. Lerrces, H., Untersuchungen tiber die Lebermoose. Jena. 1874- . Lyon, Fiomence M., The evolution of the sex organs of plants. 37:280-297. 1904. PIAA Bor. GAZ PLATE XV BOTANICAL GAZETTE, LVII 3 R ‘_ g z - ®. MANNING on PORELLA PLATE XVI BOTANICAL GAZETTE, LVII MANNING on PORELLA 1914] MANNING—PORELLA sgl aages EXPLANATION OF PLATES XV AND XVI figures were drawn with a camera lucida, except figs. 25, 28, and 29, and reduced one-half in reproduction. The magnifications appearing in the plates are as follows: figs. 1-8, 14-24, and 27, X320; figs. 9 and 26, X115; figs. 10-13, X22. Fic. 1 i Sacok cells, showing branching. Fics. 2-9.—Archegonium series. Fic. 2.—First transverse division of initial. Fic. 5.—Second vertical wall; probably a third one in plane of plate com- ser the cutting-of of a central ce 6.—Central cell (cen) has cut off cap cell; peripheral cells have divided to form jacket. — 7.—First division: of central cell. G. 8.—The axial row, comprising tl k canal cells (nc), ventral canal cell (2 and egg (e). 9.—Mature stage of an abnormal archegonium showing two distinct ais rows. = + ees P grke 45 rrulscaA Fic. 14, gE esagren tissue bef (e/) are coiled. Fic. 14, b.—Mature spore before shedding. Fics. Tk27 .—Antheridium series. 11( Fic. 15.—Antheridial initial (i) cut off from the last segment of the apical cell (a), Fic. 16.—First transverse division of the initial cell. : Fic. 17.—The second transverse division; this division may be either tanvere — vertical. Fic. 18.—A case in which the second division was vertical. Fic. G. 19 Abs this case the second division was transverse, pte aid a vertical division 1 in the upper cell; the two lower cells are the stalk Fic. 20.—Vertical divisions of the stalk cells (st). Fic. 21.—The first periclinal walls cutting off spermatogenous tissue (sp). Fic. 22.—Further division of jacket cells; sp, spermatogenous tissue. Fic. 23.—Division of Spermatogenous cells by transve Tse Ww Fic. mg —Further d Fic. 25.—Mature antheridium showing blocking of spermatogenous tissue, division of jacket cells by periclinal walls, and the slender stalk con- sisting of two rows of cells. IG. 26.—Portion of a mature antheridium showing simultaneous division of ee cells. Fic 27.—Cross-section of antheridium at stage shown in fig. : ¥ 16. 28.—Ventral view of gametophyte with one of ‘he am spite (upper one) turned back to show the lobing of the dorsal leaves; amp, amphi- 8astrium; dl, dorsal lobe; 2/, ventral lobe. Fic. 29.—Dorsal view of gametophyte with one of the dorsal lobes (d/) urned back so as to show sporophyte branch (br); per, perichaetium; 5, Sporophyte. tan af etalk THE EFFECT OF CLIMATIC CONDITIONS ON THE RATE OF GROWTH OF DATE PALMS A. E. VINSON (WITH ONE FIGURE) The observations on which this study of the effect of climate ‘on the rate of growth of date palms is based were made at the Cooperative Date Orchard, Tempe, Arizona, by F. H. Smmmons, at the suggestion and under the supervision of Director R. H. Forses of the Arizona Agricultural Experiment Station. The length of every leaf on four palms—two Deglet Noors and two Rhars—was carefully measured weekly during 1906 and 1907- By the system adopted the maximum error did not exceed one- quarter inch. In addition to the leaf measurements, daily records were kept of maximum and minimum atmospheric temperatures, and of soil temperatures at one foot, three feet, and five feet below the surface. A record of the level of the ground water was also kept, but this factor probably had no influence on the rate of growth, since the deeper roots were immersed in water at all times throughout the two years. The data representing the weekly growth of all the separate leaves are too voluminous to use in their entirety. In most cases, after a new leaf has emerged well from the central bud, it makes the greater part of its growth in five or six weeks. After that the weekly growth, as shown by elongation, becomes much less, and finally appears as a negative quantity. This is due to the base of the leaves surrounding the entire stalk, which, as it expands, tends to draw the leaf as a whole lower down on the stalk. After repeated trials to obtain from this mass of data a series of consistent and comparable figures representing weekly growth, it was found that the sum of the elongation of the inner five leaves, that were unfolded sufficiently to be measured, gave the most satisfactory series. These were then calculated for each of the four palms am plotted as a curve, the ordinates of which represent the weekly growths (fig. 1). The maximum and minimum daily temperature, Botanical Gazette, vol. 57] [324 1914] VINSON—DATE PALMS 325 and the daily soil temperature one foot below the surface at 7:00 A.M. are also plotted. The temperature factor, as influencing the rate of growth, has other components than those expressed by maximum and minimum alone, because duration of temperature is of the utmost impor- tance. The soil temperature is to a certain extent an index of all these, but in this case is modified by still other factors, such as €vaporation. Continuous thermographic records were lacking, so that it became necessary to construct somewhat arbitrary ones. In the dry air and under the clear skies of Arizona the thermo- graphic record is subject to relatively few variations from a normal form. In general the lowest point of the curve falls about sunrise, and the highest at 1:00 or 2:00 P.M. By the use of these points a fairly accurate thermographic record for this region can be drawn from the daily maximum and minimum temperatures. This alone, however, furnishes no usable data for the construction of a curve representing the total daily amount of heat received. If we assume some empirical temperature as that below which no marked growth takes place, and use this as a base line on the thermograph sheet, the areas lying above this line represent, at least relatively, the heat available for growth. The selection of such a base line is not an easy matter, and at best must be somewhat arbitrary. The data obtained, however, will be relative and consistent on any base line chosen. For the Present case 50° F. was selected, because the date palm does not seem to utilize temperatures below that, at least to any marked degree. Growth after the surface soil temperature reached 50° F. Was practically nothing. This is not to be construed as meaning that no growth would occur at a uniform temperature of 50° F., but under actual climatic conditions the minimum temperature which Would accompany a maximum of 50° F. would effectually inhibit rowth. It will be noticed in this connection that during the first Week of J anuary 1906 growth was entirely inhibited, while during the winter of 1907, when the daily maximum was always above 50 F. and the minimum seldom below 30° F., growth never entirely ceased, The curve representing the weekly heat-time areas, when plotted 326 BOTANICAL GAZETTE [APRIL along with those representing the growth of the palms, coincides in general with them, with one exception. Both years the rate of growth was maintained late into the fall considerably in excess of the amount of heat available. This may have been due to the con- tinuance of the great activity which the plant experienced during the late summer and early fall months; that is, it was in better condition to utilize the available heat at this time than at a corre- sponding period in the spring. The curves for the rate of growth show.it to be the most active, not at the period of highest maximum, but rather at that of the highest minimum temperatures, which means warm nights. This falls in July, August, and sometimes September; and it is at this time that weakly palms recover their vitality. By far the greater part of the total yearly growth falls in the last half-year. The spring growth is much less luxuriant than the fall growth. The ~ warm nights of July and August are due to the somewhat increased humidity, which prevents the usual rapid radiation after sun- down. Humidity in itself is undoubtedly an important factor, but probably has less to do with the rate of growth of date palms than with other plants. The chief relations of temperature to the rate of growth of date palms according to these measurements are: first, the period of maximum growth coincides with that of highest minimum rather than with that of highest maximum temperature, and this falls during the summer period of highest relative humidity; second, the rate of growth throughout the entire year is, in most cases, in Pf portion to the heat-time units over 50° F. The rate of maturation of the fruit is probably influenced by the same factors as the rate of growth of the foliage. The effect of high minimum temperature in promoting the maturing and ve ai ing of the Deglet Noor date has recently been called to the writers attention by M. Briguez, the civil governor of Gafsa in Southern unis. The oasis of Gafsa, which lies not over 75 miles northeast of the Djerid region, where the finest Deglet Noor dates are DEC: duced, produces only second quality fruit. The difference in alti- tude between the two oases is about goo feet, Gafsa being 1126 feet and Tozeur in the Djerid 197 feet. The two are separated by ‘906 % tea Le se = f —,s oe — ; Fe ) AS ae agar AUN Ay Let SIN Spek DIK CUAIE 4 soe a ee _— NK, ‘eG Paghics dy ie WN AW TO Ae eee a ART Tor 7 EAST IN A BS0- 6 ames Lh LE Mpar {LA ba’ N/a i” coy fl We ; ez CAC SSS V | Sey, it mesue hice CGAY IM 7 Lv Ala ee \ \ Al | oon | | Y NR ‘ t ee wren IM A LAN LAP VV i \Ne of Hf ‘fh / oa [ \ Jy f \ “Sek fatto ‘A A NTIS AS Le NIRLN@: 61/408 20a | Pa | TT AL a ] be IVY | Bae uF a VU STV, “i 7% : Meat | VV Bl DAL WZ ea 7, . Rhars—relative weekly growth *) NCP SAO § 2 Y \r Daily minimum temperatures Deglet Noor —relative weekly growth : oe pe ie : aa dee -r+t-77-t-++ Heat -time units, per week, above $0°F is I (SD It | ea are ee { eee i | f Baba lan. Feb, Mar Apr: May Sune Suly Aug Sept Oct Nov. Dec. 1907 ; is 5 i AAI eee a \ Fa Ny q aa a tas 7K —— pons T> : ~ eS : g : Se f \ a Se | 2 ee ae i \ ‘\ bs ta a ia! : i = Re rane Pgs . : me 4 li yi . —S = A Pie a eae Re ee ra —_ —— ne b= 8 a Sa UCASE ve rk 4 Z \ a | PRYASG ne NN as ee Re 5s \ \\ L < — F i 38 mas = eee ( _&£ 4 aes .— Sp." 8B, * %e, ge 2 a — —— aa vf Cs we a Ty Fic. 1.—Curves showing the relation between temperature conditions SEE Ht 1914] _ VINSON—DATE PALMS 327 several ranges of very low mountains, but the Djerid is exposed to the Sahara on the south. The result is that while the day tempera- tures at Gafsa are only 6 or Ae F. cooler than at Tozeur, the night temperatures vary by 300r35° F. Thus, high minimum temperature seems to be a more important factor in determining the maturation of the fruit than high maximum temperature. This observation is in perfect harmony with the curves for rate of growth obtained at Tempe, Arizona. ARIZONA AGRICULTURAL EXPERIMENT STATION Tucson, ARIZONA BRIEFER ARTICLES THE TYPE SPECIES OF DANTHONIA In a recent paper’ by NELSON and MacsriDE the generic name Pentameris Beauv. has been taken up for Danthonia, and our American species have been transferred with the corresponding new combinations. A quotation from this article explains the authors’ reasons for these changes. As shown by Piper in his “Flora of Washington” (Contrib. Nat. Herb. 11:122), the name Danthonia is not available for the American species that have passed under that name. In choosing among the several later names that have been proposed, he selects Merathrepta Raf. in Seringe, Bull. Bot. 1: 221. 1830, apparently because the type species of the genus was M. spicata, an American species closely congeneric with ours. But will this fact permit” our ignoring Pentameris Beauv. Agrost. 92. ¢. 18. 1812, the type species of which is accepted as a Danthonia, as that genus has until lately been under- stood ? I think the authors are justified in taking up Pentameris Beauv. in place of Merathrepta Raf., but I do not agree with them nor with PIPER in rejecting Danthonia, and I take this opportunity of recording my reasons for retaining the latter name. NELSON and MACBRIDE appat- - ently have not investigated on its merits the validity of Danthonia for | our species, because they say “as shown by Prrer.” In the article cited, Pirer merely states: “The type of Danthonia DC. is Festuca decumbens L. (Triodia decumbens R. Br.), and the name cannot there- fore be used in the current sense. Merathrepta has for its type M. spicata (L.) Raf. (Avena spicata L.).” With this statement I do not agree, and I will give my reasons. I believe that stability in botanical nomencla- ture is greatly aided by the adoption of the type method; that is, ~~ for nomenclatorial purposes a genus shall be based upon a type — and a species upon a type specimen. The selection of the type species of a genus fixes the application of the generic name to the group contai- ing the type species. It is easy to determine the type species if the genus is monotypic or if the author has indicated the type. In other cases * Western plant studies II. Bor. Gaz. 56:469. 1913. Botanical Gazette, vol. 57] : [328 1914] | BRIEFER ARTICLES 329 _ may be easy to select the type from several species by some statement of the author or because one species was figured. There are cases in which a careful weighing of evidence is necessary to determine the species which the author had chiefly in mind when establishing the genus, that is, the type species. On account of the bearing it may have on the selec- tion of type species, I give here, somewhat fully, the evidence which leads me to select Avena spicata L. instead of Festuca decumbens L. as the type species of Danthonia DC. DECANDOLLE? establishes the genus Danthonia in a local flora and hence describes only the two species growing in France. These are (1) D. decumbens, based upon Festuca decumbens, and (2) D. provincialis, a change of name for Avena calycina Vill. In a note at the end of the generic description, and preceding the descriptions of the species, is the following: “On doit, outre les espéces décrites plus bas, rapporter 4 ce genre, r°. avena spicata L. ou avena glumosa Michaux; 2°. avena calicina Lam. non Vill.” It is evident from this note that the author included these two species in his idea of the genus Danthonia. The only reason for selecting D. decumbens for the type of the genus is that it is the first of the two species described. There are more and better reasons for selecting Avena spicata as the type. It is the first species mentioned and it represents better than D. decumbens the generic idea. In regard to the last point, it is to be noted that the generic description states that the lemma (“valve externe”’) is provided with an awn, sometimes long and twisted, sometimes rudimentary (4 demi-avortée). DECANDOLLE differentiates Danthonia from Melica by the presence of the awn, and from Avena by the position of the awn, and by some other characters. It is evident that the author considered the awn to be one of the impor- tant distinguishing characters of his new genus. Three of the four species mentioned by DECANDOLLE are congeneric and possess a well marked awn. In the other species, D. decumbens, the awn is rudimen- . tary (“les valves externes des balles ont au sommet une echancrure d’ou part un rudiment d’aréte ’) and hence this species, inasmuch as it departs from the general idea of the genus, should be excluded from consideration In the selection of the type. For the reasons given I favor selecting Danthonia spicata (L.) DC. as the type species of Danthonia, thus retain- ing is generic name for our American species. Festuca decumbens L. 'S Senerally recognized as generically distinct and has been made the type of Sieglingia. Some botanists are inclined to select the type from among those species that from the standpoint of the author of the work *In Lam. and DC. Fi. Frang. 3:52. 1805. 330 BOTANICAL GAZETTE [APRIL are natives. Other things being equal, it is well to do this. But even by this method, the type would be D. provincialis DC., as this corre- sponds better to the generic description than does D. decumbens. . This selection of the type also retains the name in the traditional sense.— A. S. Hitcucock, U.S. Dept. Agriculture. A METHOD OF HANDLING MATERIAL TO BE IMBEDDED IN PARAFFINE (WITH ONE FIGURE) The account given by Mr. W. DupcEON under the above title (Bor. Gaz. 57:70-72. 1914) has suggested that some might be interested in a similar, but simpler, method which I find useful. The specimens to be imbedded in paraffine are strained from the killing solution into a small piece (2-4 inches square) of cotton chiffon held in bag form. The corners and sides are then drawn together and. tied with a piece of sewing thread (about no. 50), making such a bag as is represented in fig. 1. All surplus Fic. 1 chiffon is cut away and the bag 's put for washing in a dish into which a rubber tube brings water slowly from a faucet. Any number of bags can be washed in one dish, their contents being labeled by a small slip of paper inclosed in the bag with the specimens. The end of the . with which the bag is tied is left a few inches long, and by this the uny bags can be lifted from one solution to another until the specimens are ready to be put into paraffine. The end of the thread left hanging - over the top of the bottle does not interfere with replacing the stopper: When the specimens are ready for the paraffine, the bag is cut as just below the thread tie. It spreads open instantly as 4 flat piece of chiffon, from which the specimens can easily be transferred to the paraffine. The chiffon found best is the thin cotton quality usually sold at a veiling counter of department stores at so cents a yard; the meshes are ©.25-0.33 mm. in diameter. The material is so thin that the spears are as good as free in the solution jars, yet any number can be han : with the minimum of labor and time.—Etpa R. WALKER, U: niversily of Nebraska. 1914] BRIEFER ARTICLES 331 A CORRECTION In a review of the second edition of JOHANNSEN’S Elemente der exakien Erblichkeitslehre in the last number of this journal (Bor. Gaz. 57239. 1914), I made a very stupid error for which I wish to apologize to Dr. JoHANNSEN and to the botanical public. From the preface, in Which JOHANNSEN disclaims being a “pure Weismannian,” and from the sympathetic treatment of Semon in one of the chapters on the influence of environment, I obtained the idea that he retained a Lamarckian attitude, although disclaiming belief in experimental proof of the inheritance of acquired characters. Oddly enough, other readers of the book gained the same impression, as I learned from various conversations. This phase of the subject being necessarily somewhat ancient biological history I passed it by rather hurriedly. Recently I have read the two chapters concerned carefully, and find that JoHANN- SEN is even mote of a Weismannian in his essential principles than I had thought. His wish not to be considered as a “pure Weismannian”’ evidently rests entirely upon his opposition to WEISMANN’s morpho- logical conceptions, as I stated in the review.—E. M. East. A CORRECTION The new combination Lobaria oregana (Tuck.), made in Bor. Gaz. 563497. 1913, I find was published in Flora 47:364. 1889, by MULLER, and therefore stands Lobaria oregana (Tuck.) Miill. Arg—R. HEBER OWE, Jr. CURRENT LITERATURE BOOK REVIEWS The flora of Western China . A most interesting account of the experiences of a naturalist in Western China during several years of exploration has been given by WILSON.” Much of the work deals with the manners and customs of the non-Chinese peoples inhabiting the borderland region that was being explored, but there is also a great eal of botanical material, as the result of four expeditions. An introduction is written by Professor CHARLES S. SARGENT, in which the tree families of Eastern North America and of China are contrasted. The general statement is made that the trees of Eastern North America are larger and more valuable than the related Chinese species, but that Chinese shrubs in general produce more beautiful flowers than those of Eastern North America. In considerable detail 129 families are presented, which occur in Eastern North America and in China. Of these, 92 families are common to the two regions; 12 occur 10 Eastern North America but not in Eastern Asia; and 25 occur in Eastern Asia ‘but not in Eastern North America. In making a similar contrast with the. genera, it is found that out of 692 tree and shrub genera in the two regions, 155 are common to both; while 158 occur in Eastern North America and not In Eastern Asia, and 379 are found in Eastern Asia and not in Eastern North erica. The first volume has chiefly to do with the topography of the region and the character and customs of the peoples inhabiting it. The material of botan!- cal interest occurs chiefly in the second volume, the nature of it being indicated by the following chapter titles: the flora of Western China, a brief account of the richest temperate flora in the world ; the principal timber trees; rails : wild and cultivated; Chinese materia medica; gardens and gardening; favorite flowers cultivated by the Chinese; agriculture; the principal food-stuff croP®) the more important plant products; wild and cultivated trees of economue importance; the more important plant products; cultivated shrubs and herbs of economic value; tea and “tea-yielding” plants; the tea industry Thibetan markets. : e book is very suggestive of the botanical “travels” of years 48 which have always been the first introduction of botanists to a new region.—J. Mf ted ILson, E. H., A naturalist in Western China. 8vo. 2 vols. PP- xxxviit 257 and xi+229. figs. 111. New York: Doubleday, Page & Co. 1913. 332 1914] CURRENT LITERATURE 333 Flora of Manila In no place in the tropics has botanical work made such great strides as in the Philippines. This is particularly true of the systematic botany work of the Bureau of Science under the energetic direction of ELMER D. MERRILL. Until recently no effort had been made to collect the numerous taxonomic papers into a flora for any particular region. The flora of Manila? is not a sufficiently comprehensive title, because the work really covers the flora of the more populated coastal regions of the entire archipelago. About rooo species, or approximately one-sixth of the total number of species known from the came are described. These are distributed among 591 genera and 136 amilies. The bringing together under one cover of one-sixth of the known flora of the Philippines will make useful a large number of descriptions of plants that heretofore have been practically inaccessible to anyone except the specialist. € usefulness of the work to the layman is enhanced by definition of terms used in descriptive botany (pp. 9-20), some remarks on classification (pp. 20- 21), directions for preparing botanical specimens (pp. 21-23), some remarks on the preparation of the material for the herbarium (pp. 24-25), and a glossary of technical terms (pp. 25-33). The flora includes practically all the species of vascular cryptogams and flowering plants growing naturally within the Manila district, and most of the cultivated forms both of Philippine and of foreign origin. In it one can find descriptions of nearly all the useful and ornamental plants of the Islands, except the timber trees. It is to be hoped that the recent reorganization of the scientific staff of the Bureau of Science will not materially interfere with progress in this kind of work. Another five years ought to bring forth a flora of the Philippine Islands.—H. N. Wurrrorp. A plant physiology A plant physiology by Kotxwzrz; offers several features that are novel for @ book bearing its general title. Unusual emphasis is given to the lower forms; 60 pages are devoted to the physiology of “phanerogams” and almost 200 to the study of “cryptogams.” This change of emphasis has the advantage of ringing into prominence such cosmic cycles as the nitrogen cycle without in any way detracting from an understanding of other physiological processes. The book, however, can hardly be called a plant physiology. It contains many cece * Merritt, E. D., The flora of Manila. pp. 490. Bureau of Science, Manila. 1gt2, * Korxwrrz, R., Pflanzenphysiologie, Versuche und Beobachtung en an héheren und niederen Pflanzen einschliesslich Bakteriologie und Hydrobiologie mit Plankton- Kunde. V. 8yo, pp. 258. pls. 1-12. figs. 116. Jena: Gustav Fischer. 1914. 334 : BOTANICAL GAZETTE [APRIL pages of systematic descriptions in connection with the plankton work, includ- ing both plant and animal forms; plant morphology receives some attention, and bacteriological and plankton technique are more or less fully described. One is doubtful whether the physiological viewpoint even prevails. The book is an outgrowth of exercises that have been used in teachers’ courses for fourteen years, involving at least 25 repetitions. In spite of this, one is unable to judge whether it is more a laboratory pia: or a descriptive text. It seems poorly suited for either —WiILLIAM CROCKE. Diseases of tropical plants Cooks has published a timely volume which introduces us in a compact way to the diseases of the tropics. The study of plant pathology has been chiefly with the crop plants of the temperate regions, but with the growing interest in tropical plants, there must come a knowledge of the tropical dis- eases. This vast field has yet to be developed, but the scattered literature that does exist should be brought together, and this Cook has done in a very effective way. The spirit of the book is modern, for instead of being merely a _ list of the parasites inducing diseases, there is a chapter on the nature and symptoms of diseases, and another on the structure and functions of plants. The classification of the disease-producing fungi is restricted to a single chapter, and then a series of chapters takes up the study of the best known tropical diseases. o final — discuss prevention and control, fungicides and spraying ake. —j.M.C A weed flora PAMMELS has set the pace for a comprehensive book on the weed flora of a state. He makes the statement that a conservative estimate of the damage done to the crops of Iowa by weeds is $25,000,000 annually. If this is true, it is certainly high time the farmers should learn to recognize the dangerous weeds and eliminate them. The contents of the volume can be best indicat by the chapter titles. The first chapter is a descriptive manual (400 pP .), iD which every weed is ainetreted and its disteivution through the state indicated uponamap. Th i ws: the general character of seeds; the mi pic structure of some weed seeds; morphology of flowers and leaves; scattering of weeds; roots and rootstocks of weeds; number kind of weeds in different soils; injuriousness of weeds; weed 5 ee medicinal weeds; phenology of weeds; weeds and seed laws.—J- M.C ‘Cook, M. T., The diseases of tropical plants. 8vo. pp. xi+317- fés- %: London; Macmillan. 1913. $2.75. 5 PamMEL, L. H., The The weed flora of Iowa. Iowa Geological Survey- Bull. no. 4* pp. xili+-o12. figs. 570. 1913. 1914] CURRENT LITERATURE 335 MINOR NOTICES Index Filicum.—In 1905 Cart CHRISTENSEN published his Index Filicum, and now a supplement has appeared,® covering the period 1906-1912. The two parts are (1) the supplement, which contains all the names of ferns pub- lished during 1906-1912, and (2) corrections. In the supplement there are enumerated 33 names of new genera and subgenera that have been proposed. The number of species described as new during the period covered, and adopted: in the supplement, is 1644. Eliminating the older species that have been reduced to synonyms, and adding the new ones, the number of species of ferns Tecognized by CHRISTENSEN at the end of 1912 is 7411.—J. M. C. The fresh-water flora of Germany, Austria, and Switzerland.—Part 14 of this series of brochures has now appeared.’ The four previous parts have been noted in this journal. The present part presents the Bryophytes, and the keys, descriptions, and excellent illustrations should make their identification comparatively easy. The genera and species presented under the three groups are as follows: Sphagnales, 48 species; Bryales, 50 genera and 131 species; Hepaticae, 25 genera and 60 species.—J. M. C. NOTES FOR STUDENTS Natural vegetation and crop production.—In a careful study in one of the broad valleys in the Great Salt Lake Basin, KEARNEY? and his associates have shown that the natural vegetation of the area is so reliable an indication of the Physical and chemical conditions affecting plant life that it affords an excellent is for estimating the capabilities of the land for crop production. The Teport gives a good example of the quantitative investigation of the moisture and salt contents of the soil and the efficiency of the wilting coefficient in €xpressing the relation of the soil moisture to plant life and growth. Nearly all of the plant associations considered are dominated by a single species and very definitely limited in their extent. : The sagebrush (Artemisia tridentata) association is found in the higher Portions of the valley. With an average precipitation of 40 cm., the growth- *Curistensen, Cart, Index Filicum. Supplementum 1906-1912. pp. 132. Hafnia, Denmark: H. Hagerup. 1913. " Pascuer, A., Die Siisswasser-Flora, Deutschlands, Osterreichs, und der Schweiz. Part 14, Bryophyta, by C. H. Warnstorr, W. MoNKEMEYER, and V. SCHIFFNER. PP. 222. figs. 158. Jena: Gustav Fischer. 1914. M 5.60. * Bor. Gaz. 56: 233. 193. — ’ Kearney, T. H., Bricos, L. J., Saanrz, H. L., and others. Indicator signifi- Sance of vegetation in Tooele Valley, Utah. Jour. Agric. Research 1:365-417. 1914. 336 BOTANICAL GAZETTE [APRIL indicates land well adapted to both dry and irrigation farming, the taller and thicker the sagebrush the richer the soil. Areas next below the sagebrush are occupied by the Kochia (K. vestita) association, and this was found to indicate a soil of finer texture, with similar moisture conditions, but with only the first foot of soil free from an injurious quantity of alkali salts. Dry farming does not succeed on this area because of the small amount of soil free from alkali, while the relatively impervious nature of the soil prevents the washing out of the alkali by irrigation; hence Kochia land scarcely permits crop production. Following the Kochia belt comes the shad scale (Atriplex confertifolia) asso- ciation, with soil moisture and alkali conditions similar to the preceding, but with a soil containing much gravel. Here dry farming does not succeed, but with irrigation the alkali would be more readily washed out and hence the crop probabilities are better. The study continues with the associations of the lower, more alkaline areas, indicating as before the agricultural possibilities of the land. In addition to the value of the various associations as crop indicators, their composition is detailed, the successions noted, and the root characters of the principal species studied. The report is an excellent example of applied ecology.— G. D. Futter. The ecology of Calluna.—The common European heather, Calluna wil- garis, has been regarded as a typical calciphobe by ConTEJEAN and other pat- tisans of the chemical as opposed to the physical theory of plant distribution. Furthermore, the heather is regarded as partial to acid soils, which also are deficient in certain mineral constituents, and hence are betokened sterile. Calluna occurs in various places on the chalk downs of southern England, being accompanied by several other species that are alien to the ordinary flora of the chalk; usually the heather patches are sharply delimited from the surroun chalk associations. Miss RayNER™ has been making some detailed investiga tions of Calluna on the downs, and although much remains to be explained, a large contribution has been made to the ecology of the species. On the downs the heather grows in neutral soil, rich in most ordinary mineral constituents, but poor in lime; the roots, however, often penetrate down into soil areas are rich in lime. The proportion of magnesia is relatively high. Cultures were made in soil from the heather areas and in ordinary chalk soil contaming over 40 per cent of calcium carbonate. In the latter soil there were noted certain abnormalities, such as reduced capacity for germination and arrest * RayNeR, Miss M. C., The ecology of Calluna vulgaris. New Fiske re ‘59-77. pl. 1. figs. 2. 1913; see also preliminary paper, ibid. 10:227-249- figs. 2. 1914] CURRENT LITERATURE 337 shortly after germination, the mycelium coming from the seed coat which is infected while still in the ovary. In sterile cultures there is a complete arrest of root development. It is concluded that the so-called soil preference of Calluna depends upon the maintenance of a biological balance between the roots and the root fungi. The disturbance of this balance in soils rich in lime is responsible for poor growth in such soils. Probably also the increased bac- terial growth in the chalk cultures is detrimental. It is to be hoped that the author will make a comparative study of Callwna in its ordinary habitat, where the soil is acid and infertile —H. C. Cow es. A new Tylodendron.—Wetss" has described a new form of Tylodendron under the name T. Cowardi. Particular int in this speci t d the secretory canals and primary wood. Wetsssays: “The outer portions of the pith have very numerous secretory canals with dark brown contents, very like those found in the Medullosae, in cycads, and also in the pith of Poroxylon. d €se have not been obsetved or described, so far as I know, in any other dron, WeEIss agrees with Poronré that Tylodendron is of araucarian affinity. recently been described with discoid pith like the Cordaiteae, considerable light is thrown on the connection between the cordaitean and the araucarian forms, and that the study of this genus promises much along this line in the future.—R. B. Tuomson. Plant invasion on Hawaiian lava flows.—Thanks to the initiative of UB, we are now well informed as to the revegetation of Krakatau. The Successive lava flows from Mauna Loa, the age of many of which is exactly Known, afford an excellent opportunity for comparable investigations. € results of a preliminary study of this sort are given by Forses.” As is well known, the lava here is of two well defined sorts, the pahoehoe, which has a smooth and satiny exterior and may be ropy, and the aa, which has a cavernous and jagged exterior. Ona lava flow of 18 59, no vascular plants were found on the aa, though the surface was often white with lichens. To FoRBES’ surprise, Ricco ene * Weiss, F. E., A Tylodendron-like fossil. Mem. Proc. Manchester Phil. Soc. 57: Pp. 14. pls. 2. 1913. “Forses, C. N., Preliminary observations concerning the plant invasion on some of the lava flows of Mauna Loa, Hawaii. Occasional papers of the Bernice Pauahi Bishop Museum of Polynesian Ethnology and Natural History §:15-23. 1912. 338 ‘BOTANICAL GAZETTE [APRIL the smooth pahoehoe was much more richly covered with vegetation, which occurred, however, only in cracks n a 1907 flow plants were found just beginning to be established. The author concludes that on both types of lava, the first pioneers are lower cryptogams; on the pahkochoe these are soon suc- ceeded by ferns and seeds plants, but on the aa there is a long-enduring lichen stage. Ultimately the natural forest of the region returns, except in places where man’s influence causes the successful invasion of a naturalized flora. koa (Acacia koa) is the dominating tree of the ultimate or climax forest.— H. C. Cow es. Rainfall and soil moisture.—In studying the conditions which govern the plant activities of the semi-arid region about the Desert Laboratory, Tucson, Arizona, SHREVE’ has made weekly determinations of the soil moisture at depths of 3, 15, and 30 cm. throughout the year, and compared the resulting data with the record of the rainfall for the same period, in order to see exactly how the former is affected by the latter. It is evident that precipitation of less than 0.15 inch has no effect upon the soil moisture, and that therefore there are periods of 140 days in the region under consideration without rain ' of sufficient amount to increase the moisture in the soil. This serves to indi- cate that in desert regions by no means all of the small rainfall is significant 2 vegetation as a source of water supply. The evaporation has been determined and plotted along with its ratio to the soil moisture, the march of soil moisture throughout the year, and the distribution of rainfall, making an instructive and detailed chart of those moisture factors which affect vegetation. Among other things it proves the range of moisture conditions at the Desert Laboratory to be one of great extremes.—G. D. FULLER Drought resistance in Hopi maize.—For centuries the Indians of New _ Mexico and Arizona have grown a race of maize in soil that is much too dry for the ordinary races of the species. A large factor in the success of this race, known as Hopi maize (from the Hopi Indians), is the extraordinary capacity for elongation possessed by the mesocotyl.+ The Indians are accustom plant their maize at a depth of 15-45 cm.; this depth is for most varieties to can be induced in Hopi maize. Another advantage in the mesocot, maize is its ability to produce roots, a rare phenomenon in grass — ‘ A third feature of great importance is the great elongation of the primary 100 . . bs %s SuREVE, F., Rainfall as a determinant of soil moisture. Plant World 17°90 ? Sigs. 3. 1914. 4 Couns, G. N., A drought-resisting adaptation in seedlings of Hop! Jour. Agric. Research 1: 293-302. figs. 2. pls. 29-32. 1914. maize. 1914] CURRENT LITERATURE 339 in Hopi maize. However these striking features may have originated, it is obvious that they enable this race to grow in much more arid situations than other races of maize, and it is suggested that it may well become an important economic plant in arid regions.—H. C. Cow es. Indiana Academy of Science.—The volume of Proceedings for 1912 contains the following abstracts and papers of botanical interest: “Further notes of the seedless fruits of the common persimmon (Diospyros virginiana L.),” and “The influence of certain environic factors on the development of fern prothallia,” by AvID M. Morrier; “The mosses of Monroe County,” by F. L. Pickerr and ILDRED NOTHNAGEL; “Length of life of Arisaema triphyllum corms,” and “Acetic alcohol as a killing and fixing agent in plant histology,” by F. L. Pickett; “Plants not hitherto reported from Indiana,” by Cuas. C. DEAM; “Report of the work in corn-pollination, IV,’ by M. L. FisHer; “Conjugation in Spirogyra,” by F. M. AnpDREws; ‘Photosynthesis in submerged land plants,” by H. V. Hemmercer; “Indiana fungi, III,” by J. M. VAN Hoox; “Fungous enemies of the sweet potato in Indiana,” by C. A. Lupwic; “Notes on some puff balls of Indiana,” by FRANK D. KERN; “The improvement of medicinal plants,”’ by F. A. Mitter; “The structure and diagnostic value of the starch grain,” by R. B. Harvey.—J. M. C. tructure of tropical amphibious plants.—Material of Ipomea repians and Neptunia prostrata obtained from pools in northwestern Madagascar that are quite dry during a considerable portion of the year was examined by CHovux,% who compared the anatomy of the portions developed during the wet and dry Seasons. He found considerable differences in size and external appearance, while in internal structure the stems developed during the dry season showed (r) Proportionately greater development of vascular and fibrous tissue, together with smaller air Passages; and (2) a considerable amount of stored starch, a food reserve quite lacking in portions developed during the humid season. It would seem, therefore, that in these two tropical amphibious forms the growth activity results during the dry season in the accumulation of reserve food; While during the wet season the growth is so vigorous that it uses not only the food then manufactured, but also that which has been accumulated during the previous months.—G. D. FULLER. Osmosis in soils——The recent results obtained by LynpE,” showing that certain soils, notably the clays, promote the movement of soil water by acting aS semipermeable membranes, increasing in efficiency with their depth, suggest WSS arta ne oe *‘ CHoux, P., De l’influence de l’humidité et de la sécheresse sur la structure anatomique de deux plantes tropicales. Rev. Gén. Botanique 25:153-172- 1913. “Lynpe, C. J., Osmosis in soils. Soils act as semipermeable membranes I. Jour. Phys. Chem. 16:759-765. 1912; and LynpE, C. J., and Bares, F. W., Osmosis mn Soils act as semipermeable membranes II. Ibid., 766-78. 340 BOTANICAL GAZETTE [APRIL several applications of the theory of interest to ecologists and agriculturalists. These applications are of all the more interest because the efficiency of the soils has been shown” to be such that very considerable pressures may develop, which must be important factors in the upward movement of water in certain soils. It follows that whatever affects an increase in the concentration of the soil solution in the upper strata of such soils, whether it be the application of fertilizers or evaporation or the action of soil bacteria, aids materially in increasing the amount of water raised through the subsoil. Such factors may be involved in the increased water supply in climax mesophytic plant asso- ciations.—G,. D. FULLER. Liassic flora of Mexico.—WIELAND® has published a further study of the Liassic flora of Mixteca Alta, Mexico. The most significant botanical results were published in this journal.” The present contribution consists of a study of the composition of the flora largely for stratigraphical purposes. WIELAND shows that aggregates of species enable one to determine the age of a formation on the basis of the percentage of the major elements of the flora. He gives a table of the flora considered, with relationships to other floras that have been reported. The most conspicuous feature of this aggregate is the dominance of cycadophytes, which constitute 70 per cent of the flora. He gives illustra- tions of the overlapping of floras in the Jurassic. The suggestion of using the composition of a whole flora rather than certain species selected arbitrarily in the determination of strata seems to be a good one.—J. M The vegetation of Gothland.—THomas” has given an account of the vegetation of the Swedish island, Gothland. The island has an area of 1220 square miles, about half of which has more or less ean vegetation. Some plants rare on the mainland, as the walnut and ivy, are common here. THOMAS, using the terminology of the English ecologists, is “a about half of the island was originally fenland (the term fen, by the way, should be adopted by American ecologists, as we have no good equivalent name for this very common formation); the vegetation aspect here and the constituent species are much as in the English fens. Calcareous bogs exist, compat rab to those of Northern England. Various successions terminating in forest cap be readily worked out, and the author appeals for an intensive study before virgin conditions are altogether gone—H. C. Cow Les. 17 LynpE, C. J., and Durné, H. A., On osmosis in soils. Jour. Amer. Soc, Agron. 5:102-106. 1913. 8 WreLanp, G. R., The Liassic flora of the Mixteca Alta of Mexico; its composi- tion, age, and source. Am. Jour. Sci. 36:251-281. jigs. 2. 1913- %” Bot. GAz. 48:427-441. 1909. H. H., The vegetation of the island of Gothland. New Phytol 10:260-270. pis. 2. 1911. 1914] CURRENT LITERATURE 341 Anatomy and plant hybrids.— Miss HoLtpEn” has suggested that anatomical structures may be used in the recognition of spontaneous hybrids which are identical in external appearance with ordinary species. There can be no ques- tion but that spontaneous hybrids are of extremely common occurrence, and when they are recognized at all, they are described as variations of recognized species. She uses as illustration a case of identical external structure covering profound differences in internal organization. A hybrid between Betula pumila and B. lenta was recognized by anatomical structure which otherwise appeared to be B. pumila. Another illustration is obtained from a form of Equisetum which was clearly proved to be a hybrid. If this weapon proves 0 be as efficient as Miss HoLpEN hopes, it will go far toward attacking suc- cessfully the problem of mutations.—J. C An Arkansas prairie.—As a result of a tour of a portion of Eastern Arkan- sas, HARPER” gives us some notes upon the phytogeography of the region, the most interesting of which concern an area of natural prairie, known as Grand Prairie, in Prairie County. The plant list, made about the middle of June, shows a very rich flora, estimated at 150 species, in which the Compositae, osae, and Juncaceae are well represented. No solution is offered of the problem of the occurrence of a prairie in this old flood plain other than indications that the soil moisture shows great extremes when spring and mid- Summer conditions are contrasted. The study of such areas in Arkansas seems to have been neglected and to offer excellent opportunities for botanical investigation.—G. D. FULLER The vegetation of the Hempstead Plains—R. M. Harper presents the interesting floral features of the Hempstead Plains, which are situated in the western part of Long Island, New York.?3 In this area there is a natural Prairie of some 5° square miles in extent, stag of which shows vegetation _ €ssentially undisturbed by human influences. The commonest herb is Andro- pogon Scoparius, which also is common on many western prairies. HARPER usses the possible causes of such a prairie, without coming to definite con- clusions, except that climatic theories are ruled out, as is the influence of fire or of grazing. It is more likely, he thinks, that the Hempstead prairie is asso- ciated with some peculiar type of soil—H. C. Cow VPs Ses * HoLpen, Ruta, Anatomy as a means of diagnosis of spont plant hybrids, ence N.S. 38:32, 933. 1913. * Harper, R. Se notes on the coastal plain of Arkansas. Plant World + 7: rae * Harper, R. M., The Hempstead Plains; a natural prairie on Long Island. a - Geog. Soc. 43: 351-360. figs. 5. 1911; also Torreya 12:277-286. figs. 7. 2 342 BOTANICAL GAZETTE [APRIL Symbiosis between algae and sponges.—T wo new species of red algae have been described by Madame WEBER VAN BosseE* as belonging to the genus Thamnoclonium and living in symbiosis with a sponge which forms a continuous layer over the flattened and branching thallus of the plants. In the sponge are found imbedded small branches of the algae and also a series of filaments that are apparently epidermal outgrowths of the plant, but whose nature and origin could not be definitely determined on account of the scantiness of the material which was collected on some East Indian islands. The character of the — between the two symbionts remains to be determin G. D. Fut Flora of New Guinea.—A volume of the botanical results of the Dutch scientific exploration of New Guinea during 1912 and 1913 has appeared.’5 Previous parts of the botanical report on New Guinea were reviewed in this journal.* The present part includes the Orchidaceae by J. J. Smrra. The species number 151, included in 41 genera, of the species being desc ribed as new. By far the largest genus is Dendrobium, with 52 species, Bulbophyllum being next with 24 species. The present cane ose brings together pier publications of Smiru, who is credited with 130 of the gaan = 3 of genera. In Dendrobium, Smiru has described 47 of the 52 sp Another volume of the botanical results of the Dutch ie pa of New Guinea during 1907 and 1909 has also appeared.” The preceding part was published in 1912.% In the present part the collaborators are HANS LLIER and Tu. VALETON. Altogether 9 families are presented, all monocotyledons, including 25 genera and 113 species, 62 of which are new. Most of the con- tribution consists of the presentation of Zingiberaceae by VALETON, I including ro genera and g2 species (56 new). The large genera are Alpinia, with 35 species (22 new), and Riedelia, with 28 species (21 new).—J. M. C. A toxin from Rhizopus.—BLAKESLEE and GORTNER” ae announced the discovery of a toxin produced by Rhizopus nigricans. The xpressed juice from aerial filaments caused almost instant death when injected imeerenell into rabbits. Since this fungus has a very wide distribution, and is ** WEBER VAN Bosse, Madame A., Sur deux nouveaux cas de oases enite algues et éponges. Ann. oe oom Buitenzorg. oe 33°: 581-98 1 73 Nova Guinea. Résult Biase aeons Guinée en 1912 et 1913 sous les auspices de A. repro ghseemanti Vol Botanique. Livraison IV. 4to. pp. 1-108. pls. 1-28. Leide: E. J. Brill. 1913- Poke Gaz. 49: 464. La aio ss: set: 1913. ova Guinea. Ré tifi e Néerlandaise & la Nowell Guin Se en 1907 et 1909 sous ies auspices de Dr. H. A. Lorentz. Vol. VIII. nique. Livraison V. 4to. pp. 899-988. pls. 160-179. Leide: E. J. Brill. 1913- % Bor. Gaz. §5:462. 1913. oe * BLAKESLEE, A. F., and Gortner, Ross AIKEN, On the occurrence of a toxin uice from the bread mould, Rhizopus nigricans (Mucor stolonifer)- bint Bull, 2:542-544. 1913. 1914] CURRENT LITERATURE 343 certain to infect starchy food under suitable moisture conditions, the suspicion is suggested that it may be related to certain destructive diseases of stock, such as pellagra (“corn-stalk disease”). Experiments are being conducted to dis- cover the nature of the toxin and its possible relation to such diseases.—J. M. C. A new form of Juglans.—Baxcock* has investigated a new form of Juglans californica and described it as var. quercina, on account of the resemblance z its leaves to those of an oak. The new form has appeared on seven separa occasions among seedlings of at least three different trees of J. I OR Three working hypotheses were tested experimentally, the conclusions being vascular anatomy of the rootstock of Hoes species of Platycerium, uncovering i i icated . Comparatively simple type to a more complicated one. This anatomical Structure certainly suggests a comparison with the Marattiaceae and the Preris-like forms.—J. M. C. Mosses of New Zealand.—Drxon* has begun a publication of a series of Studies of the mosses of New Zealand, especially with reference to the her- barium of Ropert BROWN at Christchurch. The first part contains a revision of the species of Dicranoloma, 16 species being recognized, 5 of which are described as new. These species have heretofore been included under Dicra- num, and Dixon follows RENAULD’S treatment of this group as a separate genus.—J. M. C Medullosa pusilla.—In his Studies in fossil botany (1909), Scott referred to 4 very small Medullosa closely resembling the well known M. anglica except in Size. He named it provisionally M. pusilla, and now has given a further account, with illustrations.s3 Further r study shows that it differs in no impor- tant respect from M. anglica, and that its chief interest probably lies in the fact that it is the smallest Medullosa on record.—J. M. C. DS ec neg eee * Bascock, Ernest B., Studies in Juglans I: ae of a new form of Juglans s-spsmbil ten. Univ. Calif. Publ. Agric. Sci. 2:1-46. pls. I-12. 1913- N N, Harriet E., On the vascular anatomy ig the rhizome cu Platycerium. ew. oe 12:311-321. figs. 5. 1913. * Dixon, H. N., Studies in the bryology of New Zealand, with special gorges fg repeomeg of Robert Brown, Part I. New Zealand Inst. Bull. no. 3. ors 0 H., On Medullosa pusilla. Proc. Roy. Soc. London B 87: 221-228. él. a fe 2. 1914. 344 BOTANICAL GAZETTE : [APRIL Embryo of Helminthostachys.—Lanc* has supplied some much needed but the present study furnishes many additional details. The embryo extends down into the prothallium before segmentation takes place, and the first two walls are transverse. The cell next to the neck of the archegonium, which may divide or not, forms the upper suspensor tier; the middle cell, which divides, forms the second suspensor tier; while the terminal cell forms the embryo proper. The hypobasal half of the embryo forms the foot, while from the epibasal half the stem tip, first leaf, and probably the first root arise. A com- parative study of the embryogeny of Marattiaceae, Ophioglossaceae, and seed plants leads to the suggestion that “the suspensor represents the last trace of e filamentous juvenile state in development of the plant, and may have persisted in the seed-plants from their filicineous ancestry.’’—J. M. C. Basidiomycetes of the Philippines—Grarr has published a list of additions to the known Basidiomycetes of the Philippines with descriptions of new species. These additions number 33, about equally distributed between Hymenomycetes and Gasteromycetes. The new species are described in Exidia, Laschia, Lentinus, Voloaria, Naucoria, and Bovista.—J. M. C Nectaries and phylogeny.— After examining the nectaries of a large number of monocotyledons and dicotyledons, Porscu3? reaches the conclusion that the nectary is not only an organ of some phylogenetic significance, but that it rnishes additional proof of the derivation of the former from the latter-— Gok CHAMBERLAIN. # Lanc, Wit11Am H., Studies in the morphology and anatomy of the Ophioglos- saceae. II. On the embryo of Helminthostachys. Ann. Botany 28:19-37- figs. 9 pl. 3.. 1914. 38s Ann. Botany 24:611. 1910. dditions to a Se flora of the Philippines- Philippine one. Sci. 8: 299-307. pls. 8 37 Porscu, Orro, Die aa er Monskote und die Bliitennektarien- Ber. Deutsch. Bot. Gesells. 31: 580-590. 1 THE BOTANICAL GAZETTE Editor: JOHN M. COULTER MAY 1014 The Probable Origin of Oenothera Lamarckiana Ser. Hugo De Vries The Spur Shoot of the Pines Robert Boyd Thomson A Physiological Study of the Germination of Avena fatua W. M. Atwood Undescribed Plants from Guatemala and Other Central American Republics John Donnell Smith The Ovary and Embryo of Cyrtanthus sanguineu Margret — Farrell Current Literature The University of Chicago Press CHICAGO, ILLINOIS, U.S.A. Agents ee : THE CAMBRIDGE UNIVERSITY PRESS, London ond Edinburah : oe ne The Botanical Gazette HA Montblp Journal Embracing all Departments of Botanical Science Edited by JOHN M. COULTER, with the assistance of rea members of the botanical staff of the University of Chic Issued May 16, ae Vol. LVIL CONTENTS FOR MAY 1914 No. 5 THE PROBABLE ORIGIN OF OENOTHERA LAMARCKIANA SER. il ITH PLATES XV ane Hugo De Vries - - 345 THE SPUR tal OF ine PINES vt PLATES XX—XXIII AND TWO TEXT Satis’ Robert Boyd Thoms a = ae eaed A Pa ETCAL STUDY OF THE GERMINATION OF AVENA FATUA.. 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Gazette, The University of Chicago, ¢ Chica are requested to write pees: d proper names with particular care, to use the ewe system of inca: and measures, and in citations to follow the fopn shown in the peat of _ Gazette. ‘ie ae Papers. in excess of thirty- two printed pages are not accepted unless the author i is willing to a 2. a cost of the addition al pages, in a which case the number of ah age in the volume is correspondingly ee _ _THustrations urnished without cost to author only whe — originals are supplied. ple tg of ake ores made in va anuary number, 1907, wi will be sent on application. Tt ‘advisa editors as to illustrations required in any article to be eter be ust be ordered as advance — lication. “Poeny ig cepa es SEE EGE. of ter VOLUME LVII NUMBER 5 THE DOTANICAL ©7120 MAY. ror4 THE PROBABLE ORIGIN OF OENOTHERA LAMARCKIANA SER. Huco DeE VRIES (WITH PLATES XVII-XIX) In a series of most interesting articles, B. M. Davis has recently tried to prove that mutability might be a result of previous crosses. This view was first proposed by BATESON and SAUNDERS, and applies especially to the phenomena which Oenothera Lamarckiana shows when seeds from the pure strain, and even from pure lines within this strain, are sown, as in the experiments I conducted in my experimental garden. Davis expected to be able to offer the desired proof by showing that O. Lamarckiana might be duplicated by crossing two other species of the same group. Up to this time, as a matter of fact, he has not succeeded in producing any form which comes sufficiently near O. Lamarckiana to be compared with it* But if he had succeeded in doing so, evidently it would not have been a proof for his assertion, unless his hybrid should show the same degree of mutability as does O. Lamarckiana, since we have as yet no means of judging from the morphological characters of a given plant whether its hereditary characters are in a stable or in an unstable condition. - In starting his experiments to produce a duplication of LAMARCK’s evening primrose, Davis was unfortunate in the choice of the species for his combination. He chose O. biennis L. and a *For a successful duplication of an elementary species by means of crossing, See Oenothera biennis XO. cruciata Nutt. in Gruppenweise Artbildung, p. 311. 345 346 BOTANICAL GAZETTE [May form which he assumed to be O. grandiflora Aiton. It is evident that the first condition of success in such work consists in the purity and the immutability of the species which are to produce the hybrid. If they are already in a mutable condition, it is to be expected that their hybrids, or at least some of them, may com- bine the different lines of mutability of their parents; and at all events, the mutability of such a hybrid would be no proof that this phenomenon may be produced by means of crossing. On the other hand, if the species to be crossed, or even only one of them, were not pure, the hybrid might inherit this impurity and show phe- nomena which might easily be mistaken for mutations. It so happens that O. biennis is in a condition of mutability — analogous to that of O. Lamarckiana, although not developed to the same high degree. From time to time it produces dwarts, which are distinguished from it by exactly the same two characters which differentiate the dwarfs of O. Lamarckiana from their mother species, namely, low stature and sensitiveness to the attacks of some species of soil bacteria.2 Moreover, Stomps has shown that O. biennis may, although very rarely, double the number of chromo- somes in its sexual cells, which in O. Lamarckiana produces the two mutants O. gigas and O. semigigas.3 As is now generally admitted, O. gigas results from the pairing of two mutated sexual cells, each of which had a double number of chromosomes. 0. semigigas, on the other hand, is produced by the pairing of a sexual cell mutated in the same way, with a normal gamete; there- fore it possesses only 21 chromosomes (14+7), while the number in O. gigas is 28. As yet, only semigigas mutants have been observed coming from OQ. biennis, and it is obvious that the double combination must be much rarer. As a proof of this special kind of mutability in O. biennis, however, the observations of STOMPS are wholly sufficient. In quoting these facts, Davis says that if it can be shown tested strains of this biennis are able to produce new forms of specific ?Stomps, Tu. J., Mutation von Oenothera biennis L. Biol. Centralbl. ctl 535- 1912; also Zevisrra, H. H., Oenothera nanella De Vries, eine krankhafte Pian? art. Biol. Centralbl. 31:129-138. ro11. Vergl. ferner: Gruppenwelse Artbildung 1913: 296-304. 3 Stops, Tu. J., of. cit. p. 533. 1914] DE VRIES—OENOTHERA LAMARCKIANA 347 rank or even marked varieties, the mutationists would have much stronger evidence in support of the mutation theory than that based on the behavior of O. Lamarckiana.”4 After conceding this strong position to his adversaries, DAvis subjects the results of SToMPs to a rather sharp criticism, which, unfortunately, is based upon a confusion of two wholly distinct types, namely, O. biennis L. var. cruciata’ and O. cruciata Nutt. He says: “It should be made clear that the form (O. biennis cruciata) is recognized in the more recent taxonomic treatments as a true species sharply distinguished from types of biennis by its floral characters,” and “a cross between these types must certainly be regarded as a cross between two very distinct evolutionary lines and its product as a hybrid in which marked modifications of germinal constitution are to be expected.’ But, as a matter of fact, the Dutch O. biennis cruciate differs from O. biennis only in the characters of the petals; in all other respects it is wholly the same, and therefore evidently only a subordinate variety of this species. It has not been dealt with in recent taxonomic treatments, since it occurs almost exclusively in the sand dunes of Holland, where it is produced from time to time by Mutation from the mother form (first observed in 1900), without having been able until recently to multiply in the field so as to produce a persistent local variety.” On the other hand, O. cruciata Nutt. is quite a different species, with narrow, brownish green leaves, and a different type of branch- ing, of spikes, and of fruits. It grows wild in New York and Vermont, and is well known to all students of the American flora. By some authors it has been considered a variety of O. biennis, and this probably is the chief cause of Davis’ confusion. The character and the behavior of its hybrids with O. biennis have been amply dealt with in my Gruppenweise Artbildung. the experiment of Sromps, the dwarf and semigigas muta- ions were produced by hybrid strains of O. biennis and O. biennis ‘Davis, B. M., Mutations in Oenothera biennis L.? Amer. Nat. 47:116-121 €specially p. 116), 1913; see also of. cit. 47:540-596 (especially p. 567). 1913. ‘ Die Mutations-Theorie 2: 599. 1903. * Amer. Nat. 477117. 1913. Die Mutations-Theorie 2: 599. 1903. 348 BOTANICAL GAZETTE [MAY cruciata, and it was assumed that such strains would behave as true species in all characters not related to the differentiating marks of the petals. It must be conceded, therefore, that the cross of these two forms may be treated ‘‘as though-it were the combina- tion of forms within the same species, which have similar germinal constitutions” (Davis, op. cit. p. 117). But the most clear and simple way of obviating this whole objection is evidently to sow seeds of O. biennis of pure descent upon the same large scale as in the former experiment. This has been done, and a dwarf and a semigigas form have been produced by this pure line, besides some other mutations.’ They had the same characters as the former ones, and now provide us with the “strong support” asked for by Davis. Moreover, they show that his choice of O. biennis for a proof of the assertion that mutability might be produced by crossing immutable species was a most unhappy one. The second condition for success in this kind of work is, as has been stated, the purity of the types to be crossed. As already quoted, Davis assumes that a cross between two very distinct evolutionary lines may give a hybrid with marked modifications of germinal constitution. This may be applied to his choice of the type which he calls O. grandiflora, and which he has made the other parent of his initial cross. He got his seeds from Dixie Landing, Alabama, a locality where BARTRAM had discovered O. grandiflora about a century ago. He assumed them to be of the pure species, but a culture which I made in my garden from seeds kindly supplied to me by Mr. Davis proved to be a mixture, and thereby threw a distinct doubt upon the purity of the station. For this reason I visited Dixie Landing in September 1912, and had the good fortune to be accompanied by Mr. H. H. BARTLET, of Washington, well known for his systematic researches among the wild species of this group. We found the station in a most desolate condition. A small-flowered species, O. Tracyi, in almost all respects different from O. grandiflora, had migrated into the same old cotton fields and mixed everywhere with the species of Bark- *Sromps, Tu. J., Parallele Mutationen bei den Oenotheren. Ber. Deutsch. Bot. Gesells. 30: Heft 3, 1914. 1914] DE VRIES—OENOTHERA LAMARCKIANA 349 TRAM” Onno single field was the original form pure; it was always mixed to such a degree with O. Tracyi and with their hybrids that we found it impossible to collect undoubtedly pure grandiflora seed from this locality. Moreover, the intermediate types were so numerous (over a dozen) that it was difficult to regard all of them as normal hybrids between only two parents. To produce such a diversity of forms, either one or both of the parents must have een in a mutating condition, or more than two species must have combined in the crosses. In both cases, the material can hardly ’ be considered as a fit starting-point for experiments bearing upon the causal relations of crossing and mutability. Recently I have shown that besides O. biennis some other species of Oenothera are actually in a state of mutability, and espe- cially has one of the most common American types thrown off marked mutants in my experiment garden.” The degrees of development of this condition, however, are very different in different species. In some of them mutations occur rarely, but they serve to throw a doubt upon the stability of those forms for which no positive results have as yet been won. In other words, we may say that almost all the nearest allies of O. Lamarckiana are open to the suspicion of sharing at least some degree of the mutability of this species. There is no use, therefore, in trying to produce mutability by crosses of species of the same subgenus (Onagra) in order to show that this phenomenon is only a result of crossing, as is asserted by Davis. Moreover, I might point out that the question should be dealt with from a general standpoint and not be limited to the evening Primroses. If it should be true that phenomena like those of O. Lamarckiana could be produced by crossing immutable species, it would, of course, be of much higher scientific value to produce them in other families or genera, or at least in the other subgenera of the evening primroses. The chance of finding immutable parents for a cross would be far greater and the proof could be given as easily and in many cases with less amount of mechanical work * DE Vartrs, Hvco, and Barttett, H. H., The evening primroses of Dixie Land- ig, Alabama, Science N.S. 35:599-601. 1912. * Gruppenweise Artbildung, pp. 296-312. 1913. 350 BOTANICAL GAZETTE [MAY and space in the garden. The line of work chosen by DAvis seems to me to be necessarily without any chance of success. Besides his experimental work, Davis has made some historical researches to discover the origin of O. Lamarckiana.™ Unfortu- nately, he has neglected to visit the Museum d’Histoire Naturelle at Paris, where the herbarium of LAMARCK is preserved, and where other valuable documents concerning the first appearance of our species are to be found. For myself I visited these collections in 1895 and reported on the results of my investigations in my Muta- tion theory (vol. I. pp. 437-444 of the English edition). In Octo- ber 1913 I repeated my visit and compared the authentic specimens with the remarks made upon them by Davis. I regret to say that, through his ignorance of the available evidence, Davis has been led to conclusions which are fully contradicted by the herbarium material, both of the “Herbier de Lamarck” and of the “Herbier général” of the Museum. As we shall see, the origin of O. Lamarck- tana is the same as I have pointed out in my book. In the herbarium of Lamarck, O. grandiflora (Lam.), which later was renamed by SERINGE and called O. Lamarckiana, the name it still bears, is represented by two large flowering specimens. When I studied them in 1895, they were loose on their sheets and bore together the no. 12, indicating that they corresponded with no. 12 O. grandiflora of the Encyclopédie méthodique, Botanique, by Lamarck.” About 1900 they were fastened on new sheets and the numbers have been lost.% For convenience, I shall call these specimens A and B, the former being represented by our pl. XVI, while a photograph of B has been published by Davis.“ = Davis, B. M., Was Lamarcx’s evening primrose (Oenothera Lamarckiana Seringe) a form of Oenothera grandiflora Solander? Bull. Torr. Bot. Club 39:519- 533- pls. 37-39. 1912; A much desired Oenothera. Plant World 16:145-153- 19%3) The problem of the origin of Oenothera Lamarckiana. New. Phytol. 12:233-241- 1913. ™ The Mutation Theory 1:442. rgor. * The herbarium of Lamarck was acquired by the Museum d’Histoire Natarell in 1886. Vergl. Bonnet, Ep., L’herbier de Lamarck, son histoire, ses V! son état actuel. Jour. Botanique 16:129-138. 1902. 4 Davis, B. M., Was Lawarcx’s evening pri (Oenothera _Lamarckion? Seringe) a form of Oenothera grandiflora Solander ? - Bull. Torr. Bot. Club 39:519-53>" 1912. See pl. 37. - 1914) DE VRIES—OENOTHERA LAMARCKIANA 351 Unfortunately, these two specimens do not belong to the same elementary species, but the question as to which of them is to be considered as the authentic specimen has been answered by all authors in the same way, with the exception of Davis. According to the general agreement, A (pl. XVII) is the type of the species. Davis has not seen this specimen, and has based his judgment upon the communications of botanists concerned with systematic rather than with elementary species. 3 The plant A corresponds exactly with O. Lamarckiana Ser. as it is now universally cultivated and as I know it from my own cultures. The specimen is evidently a side branch, picked in the autumn, and the flowers, although very large, are not quite so large as may be seen in July and August. It bears no fruits, but the sexual organs of the flowers and the form of the flower buds do not leave the least doubt concerning its identity. The stigma lobes are widely spread and raised by the long style high above the tops of the anthers, and this is one of the best characters of 0: Lamarckiana. The buds are conical and thick, and not thin as In O. grandiflora Ait. For comparison, I have given a group of flower buds (pl. XVII), picked in the autumn also, from my pure cultures. All the other marks correspond to those of the present “Sinai although of course not all of them distinguish it from allied orms. This sheet bears the label, “d’Amérique sept., tige rameuse, haute de 3 a 4 pieds,” in the handwriting of Lamarck. The description in the Encyclopédie says of the origin of the species: “Cette espéce est originaire de l’Amérique septentrionale. On la cultive au jardin du Muséum d’Histoire Naturelle (V.S.).’"5 The description, however, quotes some points which are not visible on the herbarium specimen, nor on specimen B. It is therefore clear that the author knew his plants from another source still, Probably from the living material of the Jardin des Plantes. The Most interesting point for us is the description of the fruits: “Le fruit est une capsule courte, cylindrique, glabre, tronquée légére- ment, quadrangulaire, n’ayant environ que le tiers de la longueur *S V.S. (“vidi siccum”) means that the diagnosis is based on herbarium material. 352 BOTANICAL GAZETTE [way du tube calicinal.”** This description wholly agrees with the fruits of the present species, especially if we remember that LaMARCK based his description on a comparison with the only other large-flowered form he knew, O. longiflora. The short fruits at once distinguish our species from the allied types, such as 0. suaveolens Desf. and O. grandiflora Ait., which have thin and pro- portionally long fruits.*7 This character of the fruits shows that the description of the Encyclopédie has been based upon specimen A and not upon the other one. For, although B lacks fruits also, it belongs to an elementary species which has long and narrow fruits, as we shall soon see. Here I might point out that in systematic researches of this kind, more value is to be attached to published diagnoses and descriptions than to the material preserved in a herbarium. The older systematists, as a rule, did not take much care of their material, even if they were very careful of their descriptions.” The herbarium specimens are often found without their names and without any indication concerning their origin. ‘The rule “de- scriptio praestat herbario” applies in our special case, even as it does in mapy others. In our case, the description is relatively complete and clear, while in the dried specimen only part of the characters are represented. For all these reasons I cannot agree with Davis, who says (p. 519) that I made an incorrect determination of the material of my cultures, when I identified it with Lamarck’s plant of 1790. The authentic specimen of Lamarck and the description in the * Encyclopédie méthodique, Botanique par Lamarck, Tome IV, 1796. PP- 55°” 554, “Onagraire.” Twelve species of this genus are enumerated, 0. Jongiflora being no. 4, O. corymbosa no. 11, and O. grandiflora no. 12. A copy of the diagnosis of last one may be found in my Mutation theory (p. 441) and in the article of DAVIS. The article in the Encyclopédie is not signed and was probably written by PorRET, who prepared many articles in vol. IV, and wrote the whole of the later volumes. In the herbarium of Paris some of the specimens may be seen quoted with the authority of Porret, as, for example, on the sheet of O. suaveolens Desf., where above that name is a Ocnothera grandiflora Poiret Encyclopédie. (Cf. pl. 39 of the article of VIS. L’Oenothera grandiflora de Vherbier de LaMARCK. Rev. Gén. Botanique 25: 1914. % Cf. BONNETT, op. cit. p. 138. T1914] DE VRIES—OENOTHERA LAMARCKIANA 353 Encyclopédie correspond as closely with the characters of my plants as dried specimens and descriptions expressed in words ever can do. On the contrary, the specimen B is surrounded with doubts. Davis has given a very elaborate description of this branch, com- paring it with my Lamarckiana. The sheet bears the label: “Oeno- thera . . . . [grandiflora] . . . . nova spec. flores magni lutei, odore grato, caulis 3 pedalis.”” The fact that the name grandi- flora is placed in brackets shows that Lamarck did not wholly trust his identification of this plant with the other one. Perhaps the words “nova species” indicate that he took it to be possibly a different species. Later, Porret discovered the identity of this specimen with O. grandiflora Aiton Hort. Kew,® as has been indicated by Davis. And in De CANDOLLE’s Prodromus (3:47. 1828), SERINGE separated the two types, describing O. grandi- flora Ait. and O. Lamarckiana (SER. MSS) as different species. The words “odore grato” point to O. grandiflora Ait., which has fragrant flowers, while the flowers of O. Lamarckiana Ser. are almost without odor. In the original description no mention 1s made of the odor, and this shows once more that the specimen B was not the authentic one for this description. Davis has compared the branch B with some of his hybrid Strains from Dixie Landing” and finds a close resemblance. Per- haps the plant of Lamarck was a chance hybrid found in the Jardin des P lantes, and in this case, as Davis says, “‘we can have no certainty as to the characters of an individual plant unless its seeds have been grown in large cultures." At all events, it is not backed by other herbarium material in the Museum d’Histoire Naturelle, sofaras I know. If Porret’s opinion that it belongs to O. grandi- flora Ait. is correct, then it has evidently not served as a basis for the description of O. grandiflora Lam. (O. Lamarckiana Ser.). In O. grandiflora the fruits are thin and relatively large, for example, ” Encyclopédie méthodique. Suppl. IV, p. 141. 1816. See DAvIs, Pp. 522. ” At Dixie Landing, Alabama, only hybrid strains of O. grandiflora and O. Tracyt, fe mixed with other species too, are to be found. See Science of. cit. P- 399- 12, * Davis, B, M., A much desired Oenothera. Plant World 16:148. 1913. 354 BOTANICAL GAZETTE [May 3.cm. long and 3mm. wide; while those of O. Lamarckiana may measure 2.5 cm. in length and 6 mm. in width, making a ratio of 4° in the one case and + in the other.” The description of the fruits as short, as given by LAMARCK, evidently points to the second and not to the first case.”3 Summing up the main results of this discussion, we find that specimen A of the herbarium of Lamarck closely corresponds to the O. Lamarckiana Ser. of the present time, and has been taken by almost all authors for its prototype. The specimen B differs from it in its general aspect, in the words “‘odore grato” on its label, and in the opinion of Porret that it belongs to O. grandi- flora Ait., this opinion pointing to long and narrow fruits. Per- sonally, it impressed me as having been brought into the herbarium of Lamarck only later on, and as having been placed in the cover of O. grandiflora Lam. with a doubt shown by the placing of the name in brackets. : The best proof for the fact that A and not B is the authentic specimen of O. grandiflora Lam. is perhaps given by the specimen 0 the herbarium of Father Pourret, which was given to the Muséum d’Histoire Naturelle by Dr. BARBIER in 1847. It bears the name Ocenothera grandiflora Lam. written in the clear and beautiful hand- writing of the clerk of Pourret. In the same cover there is another sheet of Pourret’s collection, on which the same clerk wrote Oenothera biennis. Unfortunately, Davis, who did not visit the Museum, has mistaken this one for the one studied by me,” and has accordingly published a photograph (pl. 38) and a description of it. It is easily seen that this specimen really comes nearet to our present O. biennis L. than to anything else. * L’Oenothera grandiflora de Vherbier de LAMARCK, op. cit. fig. 1, 6 and ¢. %3 DAVIS (op. cit. p. 523) lays great stress on the tips of the sepals, but S : find a well defined difference between the two species in this character. : " tis attention to the word “sétacé” in LaAmarcx’s description of the ioe on “ has been translated by De Vries (Mutations-Theorie, p. 317. 1901) as “dicke.” 2 French, however, is from the late Latin word whee derived from “‘seta, hair or bristle. The meaning, therefore, is exactly the opposite of pores! DAVIS, De Vries.” If the reader will kindly look up my book = = page quoted by he will find that I have translated “sétacé” by “fad The Mutation Theory, Engl. ed. 1:442, note 2. 8 Bull. Torr. Bot. Club op. cit. p. 527. 1914] DE VRIES—OENOTHERA LAMARCKIANA 355 The plant which Pourret called O. grandiflora Lam. is repre- sented on our pl. XVIII. It agrees wholly with the present 0. Lamarckiana Ser., and in all respects. It was fastened on its sheet by the clerk of Pourret and consists of two flowering spikes and two separate flowers. The stigma lobes are seen spread above the anthers in the normal way. The specimens were picked at the beginning of the flowering period and bear no fruits; obviously they were main spikes. They will be recognized at once as OQ. Lamarckiana by anyone who has seen living cultures of this species. As I have quoted in my Mutation theory (loc. cit.), SpacH has Written on this sheet “Onagra vulgaris grandiflora Spach,’ which remark also proves the identity with O. Lamarckiana Ser. The printed label says “Collection de ’Abbé Pourret, extraite de Vherbier légué par M. le Dr. Barrer en 1847.” The main spike measures about 40 cm., the smaller one about 20 cm. In my book I have also referred to a specimen of O. suaveolens Desf. At that time I did not know the Alabama species and believed that O. swaveolens Desf. and O. grandiflora Ait. were syn- onyms, as almost all authors did. Therefore I used the two names Promiscuously. Last summer, however, I cultivated, side by side, O. suaveolens Desf. from Fontainebleau, collected by Dr. BLARING- HEM, and O. grandiflora Ait. from Castleberry, Alabama, collected by myself with Mr. BARTLETT. They proved to be wholly different species. So far as I know, the large-flowered Oenotheras, which are now relatively common in the western departments of France, all belong to O. suaveolens Desf., at least all the specimens and cultures on which I based my opinion in 1901 did. The specimen of the Muséum d’Histoire Naturelle, which I referred to especially, has been described by Davis from a photograph which is repro- duced on i. 39 of his paper. Davis, who did not know the O. suaveolens as a separate species, called it the flotsam of the her- barium (p. 529); it is, on the contrary, the authentic specimen of Desrontaings, bearing on the label the name suaveolens written by Dersrontares himself. The smaller plant, fastened on the Same sheet, has another label, saying only O. grandiflora, and seems to me to have been fastened on this sheet subsequently. The *L’Oenothera grandiflora de Vherbier de LAMARCK, loc. cit. 356 BOTANICAL GAZETTE [May larger one, however, corresponds exactly with the species which is now growing in many thousands of specimens near Samois on the eastern limit of the Forét de Fontainebleau, where I visited the different stations with Dr. BLARINGHEM in October 1913. The long fruits and the thick flower buds do not leave the least doubt concerning the identity of this specimen. The most interesting discovery in this field of historical research, however, is that of a specimen of O. Lamarckiana Ser. in the col- lection of MicHavx, described recently by BLarincHeM.” I had the advantage of studying this sheet myself, when I visited Paris in October 1913. The printed label says “Herb. Mus. Paris, Herbier de l’ Amérique septentrionale d’ANDR& Micuaux.” There is no further indication of the locality and no name. The speci- men is a main spike, picked in the beginning of the flowering period, and without fruits (pl. XIX). It is excellently preserved and corresponds in all respects to my cultures of O. Lamarckiana Ser. The lobes of the stigma are seen to be widely spread above the anthers. The flowers and flower buds are exactly those of the present species. : _ Awnpré Micwavx died in 1802, after having traveled during twelve years through the eastern United States from the Hudson River to Carolina. His celebrated collection constitutes one of the best sources of our knowledge of the flora of those parts of America at the end of the eighteenth century, that is, of the same period in which Lamarck published his volumes of the Encyclo- pédie. His herbarium is at present at the Muséum d'Histoire Naturelle at Paris, and his plants were described after his death by his son Francors ANpRé MicHaux in a book entitled ‘““ANDRAEAS MIcHAUX, Flora boreali-americana, sistens characteres plantarum quas in America septentrionali collegit ANDRAPAS Micnavx.” Micuavux had the habit of collecting seeds of 3 many species as possible, besides his herbarium specimens, and of sending them to Europe to be sown. 77 BLARINGHEM, L., L’Oenothera Lamarckiana Seringe et les Oenothéres de Fon- tainebleau. Rev. Gén. Botanique 25:1914. # Editio nova, 1820, Paris. The genus Oenothera is dealt with in vol. I on P- atte the plant is gi der tl £0. biennis. For the ground covered by his tr see the preface and the article of BLARINGHEM. ior4] DE VRIES—OENOTHERA LAMARCKIANA 357 This beautiful specimen proves that O. Lamarckiana Ser. was a component of the flora of the eastern part of Northern America at the end of the eighteenth century, and that it has come down to us as completely unaltered as may be shown by old herbarium specimens. Moreover, it tends to make it at least very probable that the European strains, or at least some of them, are derived from the importation of seeds by Mrcuaux. The specimen A in the herbarium of Lamarck, designated as “d’Amérique sept.,”” prob- ably belonged to this same strain. The exact situation of the locality where MicHAux collected this specimen is, of course, unknown. Much stress is laid by many authors upon the fact that no wild station for O. Lamarckiana has been discovered lately in any part of the United States. This argument evidently loses the main part of its weight when we know that it was observed by such a well known botanist as MICHAUX. Moreover, this situation is not peculiar to O. Lamarckiana; on the contrary, the same condition prevails for the other European species, O. biennis L., O. muricata L., and O. suaveolens Destf., - whose original stations in the United States and Canada have not been rediscovered. Even O. grandiflora, which is known to occur in Alabama in different localities, is observed there to grow on cultivated soil only, especially on old fields of corn and cotton, and no one knows whence it came. Therefore, if our present igno- Tance of the origin of O. Lamarckiana is adduced in order to throw a doubt on its reality as a good species, the same doubt is attached to its nearest allies, and, in fact, to all the dozens of elementary Species of the group Onagra which are now being found wild on waste fields and along roadsides all through the United States. Autochthonous stations are not known for any of them. A most valuable contribution to the clearance of the historical data concerning the origin of O. Lamarckiana Ser. has been brought forward by Davis in his criticism of the alleged Texan origin of the Present cultivated strain. This was introduced into the trade by Messrs. Carter and Co. of High Holborn in the neighborhood of London, about the middle of the last century. These horticultur- ists offered the seeds as coming from Texas. But, since then, no botanist is known to have seen the plant in that state, and Davis 358 BOTANICAL GAZETTE [May suggests (p. 523) that the statement might, perhaps, have been caused by a mistake.” Now, it is well known that such details are, as a rule, given more in the interest of advertising than in that of pure science. Moreover, no horticulturist likes to offer for sale seeds with the announcement that the same form may be found as a wild flower in his own country. O. Lamarckiana has been, for many years at least, a component of the flora of England, growing in many localities, especially on the sand dunes along the coast. The most universally known station is that of St. Anne’s on the Sea, near Liverpool, which has been studied by Bartey, Gates, and other botanists, and where the species occurs in thousands of specimens. Davis received seeds from different English stations and recognized the plant in the cultures derived from them (of. cit. p. 237). In Lancashire the species locally grows together with O. biennis L., exactly as it does in the sand dunes of Holland. In such cases it produces hybrids such as I have described under the names of Jaefa and velutina, and as Davis has isolated as small-flowered races from those English localities (p. 237). Now, if we agree with Davis that the seeds of Carter and Co. were derived from some English station, the probability at once arises that these English stations themselves owe their origin to the introduction of seeds from America, either by Mic#aux him- self or by some other botanist of the same period. The history of the species would then become a very simple and clear one. In this respect it becomes of interest to look at the figure published in 1807 in Smrrx’s English Botany (vol. VI. pl. 1534)-” Accord- ing to the description accompanying this plate, the “ specimen was gathered on the extensive and dreary sand banks on the coast a few miles north of Liverpool, where millions of the same species have been observed by Dr. Bostock and Mr. JoHN SHEPHERD growing perfectly wild and covering large tracts between the bt and second range of sand hills.” In this same locality O- beet L. and O. Lamarckiana are now growing in the same aD of individuals, partly separated and pure in different valleys an * See Davis in New Phytol. 12:234. 1913. * Cf. Davis, op. cit. p. 532. 1914] DE VRIES—OENOTHERA LAMARCKIANA 359 partly in mixtures which are known to contain also their hybrids. The specimen of 1807 is designated O. biennis, but both the flowers have the lobes of their stigma above the anthers, which is a differ- entiating mark of.O. Lamarckiana. Moreover, it is the only deci- sive detail, all other characters of the figures applying equally to both species. If it is allowable to trust to this detail, we should be entitled to conclude that the station of Liverpool contained both forms as early as 1807, even as it is known to do at the present time. In this case, O. Lamarckiana must be assumed to have been introduced into England about the time of Micwaux and Lamarck, and a common origin for the specimens of their herbaria and the wild stations in England becomes highly probable. The strain of Carter and Co. has been identified by LINDLEY as O. Lamarckiana Ser., and the high authority of this eminent botanist confirms my own determination of the same strain, made by comparing it with the authentic specimen of LAMARCK.* At all events, the adduced facts indicate a very simple history of our species, which has come down to us unchanged, so far as we know, from the original American habitat. ‘There is no reason to suppose that it originated as a garden plant, and none at all to subject it to all the doubts ordinarily brought forward against the purity of descent of horticultural forms in general, simply on ground that some garden plants are of known hybrid origin. O. Lamarckiana has remained unchanged through more than a century, and has kept as true to its type as any good wild species. “It is exceedingly fortunate,” says Davis (of. cit. p. 527), “that. the plant which serves as the type of Oenothera Lamarckiana Ser. should have come down to us so well preserved that there is scarcely a doubt of its identity.” But the identity is with the Species as it is still known under that name. Whether the species * Davis says (op. cit. p. 531) “the identification by Lryptey of these plants with O. Lamarckiana Ser. was undoubtedly incorrect,” but he does not give any reason for this assertion. __* Davis says (of. cit. p. 530) “that Lamarckiana has come down to us greatly modified, that its parentage is far from pure, that it is in fact of hybrid origin.” This assertion, which is not based upon any facts, is clearly contradicted by the preserva- ton in excellent condition of the three specimens of LaMARcK, Pourret, and Micnavx, not known to Davis. 360 BOTANICAL GAZETTE [MAY was in the same condition of mutability at the time of its first appearance as it is now, is of course a different question.* Summing up the results of this historical investigation, we may _ 1. Oenothera Lamarckiana Ser. is represented by specimens in the herbaria of Lamarck, Pourret, and Micuavux (pls. XVIL- XIX), and is, so far as this material enables us to judge, at the present time exactly the same plant as it was at that period. It has come down to us, through more than a century, as unaltered and as constant as true species usually do. 2. It has been a component of the flora of the eastern United States, where MicHavx collected it and whence LaMARCK derived his specimen. 3. At the present time it is a component of the flora of England, and is as well established in that country as is O. biennis in different parts of Europe. 4. The strain which is now in cultivation, and which was intro- duced into the trade about the middle of the last century, was probably derived from some wild English locality, which itself may have come from an introduction into Europe of the seeds collected either by MicHavux himself or by some other botanist of is period. AMSTERDAM EXPLANATION OF PLATES XVII-XIX Plate XVII Oenothera grandiflora Lam. (O. Lamarckiana Ser.): the authentic specimen in the herbarium of Lamarck, two-thirds natural size, referred to as 4 text; in the left upper corner a bunch of flower buds of my culture of 1913, dried and pressed, is given for comparison, and photographed togeth the main specimen. er with Plaie XVIII Oenothera grandiflora Lam. (O. Lamarckiana Ser.): the specimen hen herbarium of Father Pourret, one-third natural size; on the label is wr! Onagra vulgaris grandiflora Spach. 3 Uber die Dauer der Mutationsperiode bei Oenothera Lamarckiona- i Deutsch. Bot. Gesells. 23:382. 1905. BOTANICAL GAZETTE, LVII PLATE XVII ; sey f rT: j 4 Dameevviayee Var * Ra Mh ¢ Aba hh £ term Oleh ee . Actn /a a tigre Cada tase, haute da S AA piers "bie tas Satan ~ IE mame ———— OENOTHERA LAMARCKIANA SER. HERBARIUM OF LAMARCK BOTANICAL GAZETTE, LVII PLATE XVIII a] . cM w+. Bas bree °F be hale shards e # i AES ET A Be vs OENOTHERA LAMARCKIANA SER. HERBARIUM OF FATHER POURRET BOTANICAL GAZETTE, LVII PLATE XIX OENOTHERA LAMARCKIANA SER. HERBARIUM OF ANDRE MICHAUX 1914] DE VRIES—OENOTHERA LAMARCKIANA 361 Plate XTX Ocnothera Lamarckiana Ser. in the “Herbier de l’Amérique septentrionale” - of ANDRE Micwavx, collected about 1800 in the eastern parts of the United States: A, top of spike photographed and reproduced about natural size; B and C, the whole specimen of Micuavx, consisting of two parts, reduced about one-half; all three figures photographed for me by Dr. L. BLARINGHEM; in the reproduction the narrow bands of paper used to fix the specimen to its sheet and seen on the photographs have been omitted. ~ THE SPUR SHOOT OF THE PINES ROBERT Boyp THOMSON (WITH PLATES XX—XXIII AND TWO TEXT FIGURES) Introduction The deciduous spur shoot, with its limited growth and per- sistent whorled needle leaves, is the distinguishing vegetative feature of the genus Pinus. This structure has been generally regarded as a specialization, the more primitive form of the foliage being indicated by the single spirally arranged leaves which occur on the seedling and in some forms on the adult plant after injury. JEFFREY, however, has raised the question recently of the primitive or specialized character of the fascicled foliage of the pines in his work on the phylogeny of the conifers. He states (15, P- 331) that the spur shoot is “a primitive attribute of the coniferous stock” which “has persisted at least in a vestigial form, in connec- tion with the reproductive apparatus, long after it has disappear ed, or almost disappeared, in the vegetative axis of the living conifers, with the exception of the very ancient genus Pinus.” T his view is so entirely at variance with so many foliage features, in both the living and fossil forms, that it is difficult to see how JEFFREY could have “cast the balance of evidence” in favor of it. Since, however, he makes much of this spur shoot argument in present- ing his case for the ancestral position of the Abietineae among the other conifers, it is desirable to direct attention at least to the most important features of the evidence which is opposed to this view: The writer (27) has already stated, in a brief and general way: some of these features, in a paper dealing with the relative antiquity of the Abietineae and the Araucarineae, from the standpoint of their anatomy. New material, however, has recently come to hand which has prompted this more extended treatment of the subject. The literature has also been thoroughly canvassed for information on the spur of the pines. Of the conifers there are four genera with fascicled leaves: Cedrus, Larix, Pseudolarix, and Pinus. In the first three of these Botanical Gazette, vol. 57] [362 1914] THOMSON—SPUR SHOOT 363 the leaves are numerous, while in Pinus they are much more restricted in number, not more than 8 having been recorded up to the present. In the former, too, the number is indefinite and the leaves are spirally arranged, while in Pinus the definite cyclic arrangement has been established. A parallel to this is seen in the angiosperm flower, where the lower forms of both monocotyledons and dicotyledons have an indefinite number of floral parts in a low spiral, while in the higher forms the number is definite and the arrangement cyclic. The spur shoot of Pinus is deciduous in the second to the twentieth year (ELwEs and HENRY 7, p. 1002), and its leaves fall with it, remaining permanently attached. In the other genera it is the spur shoot which is persistent, and the leaves are cast either annually or in the second to the fifth year. The small and more or less definite number of persistent and whorled needle leaves and the regularly deciduous character of the spur shoot are features which render this structure in the pines very unlike the ordinary branch and also unlike the spurs of the other forms, which differ from an ordinary branch only in their limited primary and secondary growth. The features that will receive attention in this paper are such as indicate the branch character of the spur in Pinus. Number of needles The number of leaves in the fascicles of the pines, appearing on first sight constant, and being, as ENGLEMANN says (8), “the most obvious distinctive character,” has been extensively made use of in their classification. He states (8, p. 161) that “the sections of 2-leaved, 3-leaved, and 5-leaved pines were the only ones known to the older botanists”; to these were added two other sections “by Linx (Linnaea, 1841), one with 2 or 3, the other with 3 or 4 leaves in a sheath.” Subsequently forms with single leaves and others with 3-5 leaves in the fascicle had to find a place. Numerous exceptions to this classification have also been recorded. Kron- FELD (16, p. 68) gives a summary of the variation in many different species observed up to the date of his article. He cites, for example, the occurrence reported by REICHARDT of 3, 4, and 5 needles = oe silvestris, which is normally bifoliar, and also of 3, 4, and 6 in 364 BOTANICAL GAZETTE (MAY P. Cembra, which has usually 5 to the fascicle. To Dr. G. R. SHaw I am indebted for another reference to the 3 to 5-leaved condition in P. silvestris (see KIRCHNER, LoEW, and SHROETER, Lebensg. d. Bliitengepfl. Mitteleur. I, 187) and for one to P. halepensis, a bifoliar form which may bear 3, 4, or 5 leaves (see MATHIEU, Fi. Forest, ed. 4, 608). In Gardeners Chronicle of 1852 (p. 693) an anonymous writer speaks of having raised a variety of P. austriaca (normally bifoliar) with 3 leaves. He speaks of these fascicles as being all over the tree, which was about ro feet high and very dense. The same writer says: “I also find Pinus Hartwegii still halting between two opinions between a 3-leaved and a 5-leaved fir. . - - - Pinus mitis, P. variabilis, P. muricata, and others are too well known in their similar tendencies to need remark. My Pinus insignis has many a group of 4 leaves, instead’ of the prescribed $e" In P. macrophylla he found fascicles with 6 and 7 needles quite common, even some with 8. SHaw himself (26, p. 6), in his descrip- tion of the pines of Mexico, encountered so much variation in four of the nut pines (P. cembroides, P. monophylla, P. edulis, and P. Parryana) that he said: “I find it impossible to separate these specifically, their cones being identical and the number of their leaves inconstant.’”’ The leaves in the foregoing instance varied between 1 and 5. He has also recorded (p. 23) a great variation in single species. Of P. Montezumae he says: “Trees bearing fascicles of 6, 7, or 8 leaves are quite common, but such excessive numbers are found usually on older trees and in favorable years: On young trees fascicles of 3 and 4 leaves may be found, but in all cases fascicles of 5 predominate.” Of P. ponderosa the same author states that the leaves are in fascicles of 2-5, but has found fascicles of 6-8 on mature trees. P. Teocote, P. patula, and P. Lawsoni agree in having usually 3-to the fascicle, but the first ~ have occasionally 4 or 5, while this is more usual in the third. In P. leiophylla the conditions are evidently reversed, since mae (p. 13) says that the leaves are “in fascicles of 5 or of 3 and 4. SARGENT (24, p. 119) states of P. serotina: ‘The leaves are borne in clusters of 3 or occasionally of 4 on vigorous young shoots, while of P. heterophylla he says (p. 157): “The leaves are borne » crowded clusters of 2 or 3, the 2-leaved clusters being most common 1914] THOMSON—SPUR SHOOT 365 on young vigorous trees and on fertile branches.” In P. Pinea, which usually has the leaves in pairs, ELwes and Henry (7, p. 11g) state that ‘on well developed vigorous branches, a few of the leaves are sometimes in clusters of threes.” Of P. 7. orreyana, whose adult leaves are in fives, they also state (p. 106s) that “on young plants the leaves are frequently in clusters of 3 and 4.” Bortuwick (1) has described a tree of P. Laricio 12 years old with 2, 3, and 4 leaves to the fascicle. The quadrifoliar spurs were found only at the top of the tree, which was of very vigorous growth. The variations in the number of leaves in the pines have been tecorded practically as isolated instances and have not been correlated. As they stand, they show that the spur shoot is not So definite and so specialized a structure as has been supposed, but that it is more in the nature of a branch with an indefinite number of foliage leaves. When, however, one looks farther into the variations from the standpoint of the spur being ancestrally a branch, it is evident that the fascicles with supernumerary needles should be found in the more primitive parts of the plant: on the seedling, on the fruiting branch, after wounding, etc. My own investigations have been along these lines, and though they do not completely correlate the cases reported, they go very far toward doing so and afford one important line of evidence of the branch character of the spur shoot. Fig. 1 is of the upper part of a 3-year-old seedling of P. Strobus.* Primordial leaves are unusually persistent on this plant, and may be seen among and below the three spurs with the rubber bands around their leaves. Brown scale leaves, however, replace these green seedling leaves around the base of each fascicle just as in the ordinary spur. The middle spur bears 15 leaves, the one to the Tight 11, and the one to the left 7. Fig. 2 is of a seedling of the Same species, one year older. The main axis in this case made a comparatively short growth the last season and bears 6 fascicles. The central one of these has g leaves, the one to its right 10, the two below these 7 each, the lowermost to the right 5 large and 2 *I cannot determine absolutely that these and the other young forms are P. Strobus. It is possible that they are P. excelsa, but, since some consider the two sy as geographical varieties, the matter is unimportant from the present stand- t. 366 BOTANICAL GAZETTE [MAY small, while the lowest to the left has 6 equal-sized needles. This plant was slightly wounded a year ago last spring in connection with some work a student is doing along another line. It was not injured, however, in such a way as has been found in other cases to interfere with the number of needles. Again, several sister plants similarly injured did not show any reaction. It is probably better to consider this case a ‘“‘sport,” just as in the case of the 3-year-old plant, which had not been injured in any way so far as could be determined. In only one instance have I found younger plants than these with extra leaves in their fascicles; one seedling from a dozen or so of P. flexilis, which are now in their second year, has a fascicle with 6 needles. It is among the first formed fascicles of the seedling and at the top of the second season’s growth. It is more usual to find the spurs poorly developed when they first appear on the seedling, which is generally in its second year, though in some species they are delayed till the third year, or even later. This feature shows itself especially in species which have ‘normally more than two leaves in the mature condition. For example, HempeL and WILHELM (11) refer to P. Cembra seedlings two years old as having trifoliar spurs, though the adult plant 1s normally quinquefoliate. I have also found trifoliar spurs common in P. Strobus when fascicles first appear on the seedling. Some spurs here are even bifoliar. In these reduced spurs the needles apparently come right out of the stem, the shoot axis, if any be present, being imbedded in the tissue. These fascicles also are usually devoid or almost devoid of bracts. In P. silvestris I found in 35 seedlings two years old only one example of a trifoliar spur- This was on the most vigorous of the plants. In plants a few years older, which had attained to considerable vigor of growth, I could scarcely find one without trifoliar spurs unless it was 4 weakling. At first the occurrence of these reduced fascicles on the seedling seemed entirely at variance with the view that the spur shoot of the pines is a branch. It is a feature, however, which is shared by other spur shoot-bearing plants. In Ginkgo, for example, when the spurs first appear, about the third year, they bear only 1-3 nil 4 leaves, and gradually gain in number as they advance in age UP 1914] THOMSON—SPUR SHOOT 367 they attain their mature condition. This is also true of the other fascicle-leaved conifers, sometimes only one or two needles develop- ing in the season that the spurs appear. There must thus be some common physiological reason underlying this feature, and no doubt it is the well known lack of vegetative vigor in the seedlings of the conifers generally. During the first few years they are busy estab- lishing a root system and there is little stem growth. Foresters and nurserymen know this early critical stage in the life of the conifers only too well. The growth in these early years could be measured in inches, while in later years it would require feet. I have examined older forms, 6-15 years old, of a large number of different species belonging to all the different sections of the pines, and have found supernumerary needles quite common, especially on vigorous specimens. On the main axis of one unusu- . ally sturdy plant of P. Strobus, a plant which had made at least a foot and a half of stem this year, and this stem fully three-quarters of an inch in thickness at its base, there was a spiral sequence of fascicles with 6, 7, 8, 9, and 10 needles. Fig. 4 is of one of these. The supernumerary needles have been surrounded by a rubber band, and it will be seen that they show a spiral gradation in length. This is a feature which to a less degree is sometimes shown by the 5 original needles themselves. It is indicative of the concealed spiral arrangement of the leaves on the spur. This feature, I find, was observed long ago by MEEHAN (22), and its significance noted. The series of spurs referred to above occurred on the lower part of the year’s growth. It is more usual, however, to find spurs with extra needles near the apex of the season’s growth. I have found many instances of this in a mixed plantation of pines about 8 years of age, which consisted of P. Sirobus, P. silvestris, and P. Banksiana, Of the white pine there was a large proportion of vigorous specimens with supernumerary needles. The Banksian pine showed few instances, but in the Scotch pines they were very numerous. I should think fully 75 per cent of these had several (3-6 or 7) trifoliar spurs at the apex of the year’s growth. These trifoliar spurs could be traced for two to three years previously at the corresponding places on the stem. The occurrence of tri- foliar spurs in this species at the branch region was observed by 368 BOTANICAL GAZETTE [MAY the anonymous writer in Gardeners Chronicle of 1852, to whom reference has already been made. He says of these spurs in P. silvestris: “J have gathered 8 or 10 examples round one bud alone,” and adds ‘“‘on the macrophylla the examples are very numerous,” evidently intending it to be understood that the abnormal fascicles of this species, which he has described with 6-8 needles, were also found in the branch region. I have observed in P. excelsa 6-7 needles in the same position, in P. parviflora 6, and in P. virginiana 3. The first two of these are normally 5-foliate, while the third is 2-foliate. In P. Jeffreyi, which is normally 2~-3-foliate, I have found on plants of about 8 years of age spurs with 5-6 needles; these were often in a terminal position (see fig. 13, where a branch has originated from such a spur). In all cases it is more usual for _ the extra numbers to appear on the main axis than on branches, though I have found them on the same plant in both places. I have examined fruiting branches in the case of P. Strobus and P. excelsa only, and have found several instances of 6-needled fascicles on these. This normal production of supernumerary leaved fascicles, as it may be considered, is interesting, but of much greater interest is their traumatic production. The past summer, Mr. J. FRYER was experimenting with white pine along this line and succeeded in producing on young trees, about 15 feet high, fascicles of 6-8 leaves, in one instance 11. He cut the young growth from vigorous branches and main axes in the latter part of May, and when new growths arose they had in some cases the extra needles in the fascicles. In P. excelsa, at about the same height, I found in the middle of July many such cases, where the terminal bud had been injured in the early spring (probably by the pine shoot beetle, Hylesinus piniperda) when the fascicles were beginning to develop. The wounding caused numbers of these fascicles to develop extra leaves. Fig. 3 gives a fair illustration of the tufted appearance of these shoots and shows three fascicles with 9-11 needles (see in fig. to the central fascicle). In some instances the number of leaves reached 15. In P. parviflora I have found on a young tree fascicles of 6-9 needles. These were near the top of the. ee axis, which had been slightly wounded lower down. Even 9 the 1914] ; THOMSON—SPUR SHOOT 369 single-leaved pine, P. monophylla, wounding increases the number of needles to two. Figs. 5 and 9 are from a young tree which was normally monophyllous. Both twigs were injured just as the leaves were starting to develop. On the first, three bifoliar spurs have been produced, and on the second, one. I have not observed an increase in the ‘number of needles by wounding in any other forms, but it is probably of quite general occurrence in the pines. Before leaving the subject of the number of leaves in the fascicle, a peculiar and probably a specialized condition, which has been reported in several species, must be referred to. In P. Nelsoni, SHAW (26, p. 8) states that the leaves are “connate in fascicles of 3,’ and that this condition is found even in the seedling. In P. Thunbergii the leaves are in twos, while “in var. monophylla the two leaves in the cluster coalesce”’ according to ELwEes and HENRY (7, p. 1143). These authors also refer to two other cases of fusion of the leaves; to CarRrtERE’s (Conif. p. 398, 1867) description of a variety (monophylla) of P. excelsa: “each sheath with apparently only one leaf, all of the five leaves being welded together”’ (p. 1011), and to a monophyllous variety of P. Strobus described by TUBEUF in 1897, “‘a variety with the needles more or less cohering through- out their length, and forming a single needle” (p. 1026). It is hecessary to distinguish this spurious monophyllous condition, a result of compounding, from the truly single-leaved condition in the one species, P. monophylla, which as MASTERS (20) has shown arises from the “arrested development of one of its two original leaves” (p. 126). Scale and primordial leaves Below the persistent whorled needle leaves on the spur shoots are spirally arranged scale leaves, which are homologous with the similarly though more laxly arranged scale leaves on the ordinary branches. They are either persistent or deciduous. On seedling stem and branches scale leaves are replaced by the so-called pri- mordial leaves, which are a prominent feature in the pines. These Seedling leaves, as Coutrer and CHAMBERLAIN (5, p. 222) have noted, are of simpler structure than the whorled needles. There 370 BOTANICAL GAZETTE [MAY are gradations in structure, however, between the two types of foliage. BoRTHWICK (1, p. 153) refers to this feature in his descrip- tion of the supernumerary needles of P. Laricio, to which reference has been made. He says that “the fourth needle,. . . . although it shows some of the primary leaf characters internally, still, in outward appearance, it resembles the normal acicular leaves, exhibiting in fact a transition stage between the two.” I have found very complete series of transitions in form between both scale and primordial leaves, and also between these and the whorled needle leaves. The latter is well indicated in fig. 10, where the upper spur (5-foliate) has proliferated into a branch with primordial leaves. It is possible here to tell the spur leaves from the others only by their low spiral arrangement and by their slightly triangular rather than flat form. In the fascicles illustrated in fig. 3, some of the upper bracts have been modified into green seedling-like leaves. The needles of these fascicles, too, are flatter, shorter, and more like the primordial type. This is especially true of the needles of the fascicles in the younger plant shown in fig. 1. More definite reference to these points will be made in a future paper dealing with the internal structure. The morphological evidence, however, seems sufficiently clear that the spur shoot leaf is only a specialized primordial leaf, just as the scale leaf is also a modification of it. The transformation to both types of foliage occurs at somewhat different stages in the life of the seedling of various pines. O P. monophylla, SARGENT (24, p. 51) says: “primary leaves are the only ones produced during the first five or six years in the life of the plant”; while Brirron (3, p. 14), in referring to this feature in P. cembroides, states: “juvenile leaves of this and other nut pines are produced for the first five years or more, often to the exclusion of all others . . . . the new ones shorter as the buds of the fascicled, needle-shaped leaves develop in their axils. Masters (21, fig. 1, p. 586) has figured the persistent primordial leaves of one of these, P. Parryana. He previously figured those of P. Pinea, a form in which he notes that they were observed long ago by Linnaeus (MAsTERs 19, p. 258 and fig. 8). Of the last mentioned species, ELwEs and HEnry (7, p. 1120) state that “the primary leaves are produced . . . . for several years, in mixture, 1914] THOMSON—SPUR SHOOT 371 after the first season, with the adult geminate leaves.’’ Lioyp’s (18) attention was attracted to the great persistence of the primary leaves of a young plant growing in the New York Botanic Gardens. In P. canariensis the leaves persist even longer than in P. Pinea. In P. rigida they are also very persistent. In the seedlings of most forms, however, the primordial leaves do not last beyond the second or third year. Primordial leaves are not, however, restricted to the seedling. According to Masters (19, p. 258), ‘they occur frequently on the lower part of the shoots of the year, as in Pinus sabiniana, Pinea, silvestris (sometimes), and other species’; also “in some cases, on the branches or stalks immediately supporting the cones, as in Pinus excelsa, etc.” In P. monophylla, Etwes and HENRY (7, p. 1056) have noted that “in cultivation adventitious shoots bearing flattened primordial leaves are occasionally produced on the lower branches.” SHAw (25, p. 206), in speaking of the “‘sum- mer”’ growth of certain southern pines of the United States, says: “this growth, in the summer, differs from the spring growth not only in its less development, but also in its green bracts, which, not being required for the protection of the winter bud, assume more or less completely the size, color, and character of the primary leaf.” Sarcent (24, p. 4) states that: “Pinus rigida and Pinus echinata are the species of the United States which generally bear primary leaves on branches, or produce freely shoots from the stumps of cut trees. These shoots, which are clothed with primary leaves, grow vigorously for a few years, and then usually perish.” ENGELMANN (8, p. 163) speaks of this feature in P. inops, P. rigida, and P. canariensis. In the last mentioned, it is very prominent in some instances. Miss Coorey (4) refers to and figures a tree at Naples which was practically clothed with shoots bearing Primary leaves. A young specimen of the same species in the New York Botanic Garden shows many reversions to primary foliage. Whether in these instances all the reversions may not be the result of injury is uncertain. Wounding does give a response in the case of the production of resin canals for several years after the injury, especially prominent being the response in young twigs which are formed subsequently to the wound, and it is probable 372 BOTANICAL GAZETTE [May that the extent of the primary leaves due to wounding is much greater than at first appears. The possibility of reviving the primary type of foliage by wound- ing must be fairly common in the pines, for in addition to the ones that have been mentioned, MASTERS (19, p. 258) refers to their production after injury in P. edulis, P. Parryana, and P. Khasyana. The past summer I have observed it in ten or more species: P. canariensis, excelsa, halepensis, Jeffreyi, Laricio and var. ausiriaca, monophylla, Pinaster, Pinea, ponderosa, Thunbergii, and tuberculata. LOYD, moreover, has produced the primary type of foliage experi- mentally in P. ponderosa. He states (18, p. ror; see also original article, 17) that “shoots, which normally would bear only thin, brown, papery scales, namely the shoots which bear the male or _ pollen-bearing cones, may be made to produce true primordial leaves by the mere pruning away of the upper part of the shoot early in the spring.” HocusTetrer (12) has gone farther, and has succeeded in fixing the juvenile foliage in P. Pinea and P. canariensis by cuttings, having accomplished in this specialized genus of the Abietineae what is common practice in the Cupressineae. He states (p. 367): ‘“Stecklinge von Pinus canariensis und Pinea- Samlingen, im zweiten oder dritten Jahre abgenommen, wachsen leicht an, verharren in der Primordial-form und bilden blaiulich- griine Biische mit spiralig einzeln gestellten Nadeln von unvergleicher Schénheit.’’ Unfortunately, these “ | mag when the germination ~-.9 was averaging about 60 per cent for intact seeds. It is evident that the \ ™ . . * > fe : absorption rate 1s raised noticeably by searing. In most of the curves, n6 a steady tendency is noted for the rate of absorption to rise with the length of the period tested. In many cases the high absorption —_—_—_—" ue 10 Hours 30 noted beyond the 25-3° Fic. 9.—Rates of oxygen absorption for wild hour periods is asso- oats for December and early January in terms of ciated with the breaking + CC. = . . c. per hour per gm. dry weight; rate for intact of the seed coats ™ seeds, solid line; for seeds tested in 93 per cent oxygen, broken line. germination. Earlier : increases in rate, how- shoes: must not be ascribed to this cause. If now for this same period comparison be made of the absorption rates in the air and in an atmosphere of 93 per cent oxygen, the difference between the two conditions is marked (fig. 9). Further tests in 79 per cent oxygen revealed rates midway between those found for air and for 93 per cent oxygen; while absorption in 7 per cent oxygen 1914] ATWOOD—GERMINATION OF AVENA 403. showed much lower rates the same period than were obtained in air. Oxygen absorption tests of freshly harvested wild oats were made during July 1913 at temperatures of 1692 C. and 26°2'C. It was thought possible that the failure or success of the VAN’T Horr temperature law of chemical reaction to hold with the fresh seed might, in connection with the other data, throw some light on the power of the seed coat to exclude oxygen. Summarizing a number of readings, it was found that Bee the rate at 26°2 C. 0.160 the rate at 16°2 C. 0.067 =2.38. This is quite what might be expected if the coat offered no re- striction to gaseous penetration, and appears at first to conflict with the data derived on this point in other tests. However, we cannot as yet say what effect such a temperature change may exert on the permeability of the coat, which is a non-living structure. It is a well known fact that the solubility of oxygen in water decreases with a rise in temperature. Thus, the absorption at 35° C. is 56.9 per cent of that occurring at 5° C. GASSNER in a recent article (28), as reviewed by LEHMANN (48), believes that € beneficial results obtained in germination of Chloris ciliata through the use of low temperatures may be due to the greater absorption of oxygen at these cemeratures. He employed tem- peratures varying from 5° C. to 34° C. LepPESCHKIN (50) and others, however, have pointed out the fact that the permeability of living protoplasm to gases increases with rising temperature. It is thus quite possible that the problem of oxygen absorption by the grasses may be complicated by the opposite influence of high temperature on the solubility of oxygen in the water in the seed, and on the permeability of the seed coat itself. Conclusions on these tests must hence be delayed pending further investigation of the effect of varying temperatures on the permeability of non- living membranes to gases. As it was noted that in every germination test a large number of seeds laid dormant, yet if forced by searing would promptly or minate, the experiment was tried of testing the oxygen-absorption 404 BOTANICAL GAZETTE [MAY rate with seeds selected after lying dormant five days under the usual germinative conditions. The results showed a much lower Aan absorption rate, both in air and in 93 per cent oxygen, than was the case in tests made with unselected seed. Furthermore, the differ- ence between the rates ih air and in higher concentrations of oxygen was not so marked. It oJ is realized, of course, “a that the “‘selected seed” , was not in behavior to be strictly compared with seed treated in the usual se Se A: a manner, as they were we Via subjected to a tempera- Pe wes ture of 21° C., in the the respirometer test. The oxygen absorp- tion seemed to be prac- ae 3 a period that germination é oe was attempted before 93 . _— +. AEN tically the same for seeds seared dry one month before testing, and those seared after one night of soaking in the ice box, just previous to placing eee 10 Hours 30 in the respirometer. * . . . i Fic. 10.—Comparative rates of oxygen absorp- The similarity mm germ tion for tame and wild oats in terms of cc. perhour, native behavior of the per gm. dry weight; Avena sativaindicatedbyT,and seeds treated in these Avena fatua by W; rates for intact seeds, solid line: : : , ; noted for seared seeds, broken line. two ways has been above. Other workers (6, 58, 62) have studied the influence of wounding on respiration as measured by the resultant carbon dioxide releasal. JUNITZKEY (40) holds that oxygen absorption and carbon dioxide releasal may be phenomena independent of each other. In any case, We Me concerned here only with the direct rate of oxygen absorption by the seed as bearing on the problem of germination. For this oS » 1914] ATWOOD—GERMINATION OF AVENA 405 reason it is of interest to note that the temporary ‘‘ wound effects” noted for other tissues with carbon dioxide as a basis of decision, do not hold for the oxygen intake of Avena fatua. As the early germinative delays of A. sativa are so much less pro- nounced than is the case for A. fatua, it is of interest to compare the oxygen-absorption 30 rates for the two (fig. 10). The tame eas. SERA oat shows a_ higher ee eee isi rate throughout. It was impossible ance: comreamaay ceeigc = Cay Same & to carry out these ra tests (summarized in -227———7__—sd Pos fig. 10) until April, pf when the comparative vy difference in germina- emma CERES, tive delay between a ~ a — the tame and the wild rere Bea Gags eeet eat is much léss than 4g) te 1 Sees SATEREL in the preceding oat autumn. This makes sapemeoane ea it seem probable that a a when fresh seed may : again be obtainable, eR iets HE ReeGeD ERE the differences in rate ees found above, though -06 190 Hours 30 50 quite marked, may Fic. 11.—Rates of oxygen absorption for be even more con- intact wild oats before and subsequent to after- spicuous. sipening, to tern Oh Oe Pe a weight; rates in winter, solid line; in spring, In figs. 11-13 are heoken: tne shown respectivel pace the effect of nee on the rate of oxygen intake by intact seeds, seared seeds, and seeds run in an atmosphere of ee 4 per cent oxygen. The temperatures employed were identical 65 the 24 tests here summarized. In each case the winter rate 1s indicated by the unbroken lines, and the spring rate by broken lines. A consistent increase in the rate of oxygen absorption in 406 ; BOTANICAL GAZETTE [MAY higher concentrations is shown. This increase is least noticeable in the case of the high percentage of oxygen tests. It is suggested that if coat restrictions are concerned, and if their effects are over- come by high concentrations of oxygen, the four curves would tend to come together, as is found to be the case. Summarizing the ~30 ug ‘ respiration tests, it would seem that asso- eA ciated with increased 7 germinative rates = /| accompanying after- 7 ripening there is an in- 4 < creased ability of the ac Pet seed to take up oxygen, ie 7 was providing always that the conditions of germi- ~ —-—— : os nation be the same; and, 45 further, that wounding and subjecting to in- creased oxygen con- centrations actually - increases the oxygen in- take. Nevertheless, the process of after-ripening may not consist pri- mils} ; ‘ n ° marily in an increased : 10 Hours 30 5 ) Fic. 12.—Rates of oxygen ab tion f a wild oats before and subsequent to aiter-ripening in terms of cc. per hour per gm. dry weight; rates in winter, solid line; in spring, broken line. freed from limitations to absorption, as was ac complished in the experiments summarized in fig. 12, it is apparent that their oxygen-absorption rate closely approximates that of the seeds which have thoroughly after-ripened. Thus the changes, whether they be seed coat or embryonal, which we ordinarily term after-ripening, and which are exhibited by increased rate of oxyge intake, may be immediately attained by artificially overcoming 1914] ATWOOD—GERMINATION OF AVENA 407 the limitations to oxygen entry, if rate of absorption be taken as a basis of judgment. 7. DETERMINATION OF EMBRYO ACIDITY.—Investigation has been begun as to variations in the acidity of the embryo in after- ripening, and comparisons have been made with the embryos of | mi sativd. To test... this condition, the ~ , seeds were soaked Over night in the ice Se Wk box, and then sub- re y jected to identical Z germinative con- WY ditions for about 18 +22 zt’ hours. The embryos Fred were then removed, A. if accurately weighed, 8 carefully ground, and 8 / : : : me immediately titrated with N/2o0 alkali in the presence of phe- nolphthalein. Water content of the em- bryos was determined on other parallel neta samples, from which data the dry weight 06 10 Hours 30 50 of the titrated em- Fic. 13.—Rates of oxygen absorption for wild bryos could be com- oats in ce - a of oxygen diac go 8 . : su uent €r-fl the mimber of eof AED emy wet tes init i in spring, broken line N/2o alkali necessary : to neutralize the acidity of the equivalent of one gram dry weight of the embryos, the results given in table VII were obtained. _ It will be noticed that the 1912 samples grown at Chicago were tested early and were less acid than corresponding year old samples of both the tame and of the wild. Further, the acidity is less in A. fatwa seeds one year old than in A. sativa just harvested. 408 : BOTANICAL GAZETTE [May Comparing the degree of acidity of the various samples with the moisture contained in the respective embryos, the relations appearing in table VIII are found. TABLE VII EMBRYO ACIDITY COMPARISONS OF AVENA FATUA AND A. SATIVA TESTED AUGUST I912 N/20 ALKALI FOR I GM. DRY WEIGHT Kind Season grown ‘Tame (Swedish select). 2... «5... 05. ceeees IQII 3-79 Tame (Swedish select) tested fresh....... IQI2 2.51 Tame RUG Oe ee oe oe ee ees IQII S231 Wor (indie Head) 6 a ee IgIt 2.37 Wild (grown Chicago) tested fresh ....... 1912 1.87 It is seen that there is a general tendency for the water-holding power and the acidity to rise contemporaneously. This situation was noted by Miss EcKerson for Crataegus. It is possible that such embryonic changes in A. fatua may be causally related to alterations in inclosing structures. Further investigation of the chemistry of the embryo is planned. TABLE VUI N/2o alkali to titrate 1 gm. dry weight = peat seg e Be ee ei ie ce 50.2 Se eo oO ees 56.0 Bo TA PAE Scr ea ue vets eine eee 54-3 Bahk ee Fe ra es eS 71.0 Oe ee ae ce 68.3 8. ConcLusions.—The combined results, so far noted, namely, that germination can -be increased by various coat-breaking methods; that germination may at all stages be improved by increased oxygen; that when wounded or subjected to increased concentrations of oxygen there is an absolute increase in the rate of oxygen absorption; all seem to point to the conclusion ‘that oxygen supply is for the freshly harvested wild oat the limiting factor to germination, with the probability that coat restrictions to oxygen entry play a réle. The question still is open as to the nature of the physiological processes for which oxygen is thus essenue’ Griiss (31) believes that in the case of Phaseolus the abundant 1914] ATWOOD—GERMINATION OF AVENA 409 enzyme content in the cells neighboring a wound occurs as a resylt of the action of oxygen on the reserve proteins. LEHMANN (49) believes germination stimuli are effective through their influence on protein hydrolysis. “The work of Miss EckERSON and of GREEN Suggests the possibility that the development of acidity leads to the liberation of enzymes. What relationship, if any, there may be between acidity, oxygen, enzymes, and germinating power in A. fatua is worthy of further investigation. The character of the changes in the seed of A. fatua with after-ripening remains to be discovered. Oxygen being considered the limiting factor to germination for the freshly harvested seed, it is possible to consider that the embryo in the course of after-ripening either decreases in its demands for oxygen, whereby the seeds become able to grow in gases poor in oxygen; or we may suppose that there is no decrease in oxygen demands, but rather an increased permeability of the coat'to oxygen. The fact that after-ripened seeds can grow better than fresh seeds in chambers poor in oxygen, although the former regularly absorb oxygen at a more rapid rate in respiration under normal conditions, together with the results (as shown graphically in fig. 13) that fresh and after-ripened seeds in the presence of high percentages of oxygen absorb at similar rates, seem to favor, but not to prove, the general idea that the coat exclusion to oxygen be- comes less complete as the seed after-ripens. What mechanism is released by the greater oxygen supplied either artificially through breaking the coat, or submitting the seed to high percentages of oxygen, or under natural conditions through a slowly developed in- crease in the coat’s permeability to oxygen, is as yet an open question. If further investigation upholds the data given above, showing an increased acidity of the embryo with after-ripening, we must recognize the fact that in A. fatwa after-ripening involves, in addition to physical changes of the coat, accompanying chemical alterations of the embryo itself. IV. Summary - 1. The germination of A. fatwa has been found less delayed with the shell coats removed from the seed. However, with the shell coats removed, there exist after harvest germinative delays 410 BOTANICAL GAZETTE [MAY which disappear with subsequent weeks. Hence the after-ripening of the seed occurs independent of the shell coats. 2. The after-ripening occurs along with the drying of the seed, but independent of the water content, as air-dried seed soon after harvest yields lower germinative percentages than seeds of similar moisture content the succeeding spring. 3. The germination seems unaffected by light. : 4. Exclusion of water by the true seed coat does not seem to explain after-ripening. 5. The delay in germination is occasioned by restriction in the supply of oxygen, which thus acts as a limiting factor to germina- ion. The seed coat is probably an obstruction to oxygen entry. This general situation seems pointed to by the combined results obtained by breaking and searing the seed coat; by removal of the embryo; by germinative percentages obtained in varying concen- trations of oxygen, both below and above the normal of the air; by direct measurement of the rate of oxygen intake with intact and seared seeds, and with seeds in varying concentrations of oxygen. 6. The exact nature of the changes in the seed which constitute after-ripening cannot be stated positively. However, the data obtained seem to point to an increased permeability of the seed coat to oxygen, together with a rise in the embryo acid content, which is accompanined by increased water-absorbing power of the embryo. I wish to acknowledge the cooperation of Dr. WILLIAM CrocKER who suggested the above problem, and has throughout been ready with helpful suggestions. I am also indebted to Miss Eckerson for bibliographical material, and to my father, Mr- J. R. Arwoon, for assistance in the tedious labor of preparing the seed for tests. LITERATURE CITED 1, ABDERHALDEN, E., und Dammuann, Uber den Gehalt ungekeimter und gekeimter Samen verschiedener Pflanzenarten an peptolytischen Fer- menten. Zeitschr. Physiol. Chem. 57: 332-338. 1908. 2. APPLEMAN, CHARLES O., Physiological behavior of enzymes and carbohy- drate transformations in after-ripening of the potato tuber. §2:306-315. 1911. 1914] ATWOOD—GERMINATION OF AVENA 4II 3. ATTERBERG, ALBERT, Die Nachreife des Getreides. Landw. Versuchs- tat. 67:129-143. 1907. 4. BEAL, W. J., Vitality of seed. Bor. Gaz. 40:140-143. 1905. 5. Buzisce, C., Der Einfluss heisser tulparcacktn apy auf die Keimung der Gerste. Zeitschr. Gesells. Brau. 33:538-539. 19 6. Borum, Josern, Uber die Respiration der Kartofiel. ce) Zeit. 45:671- 675, 682-691. 1887. . BRIGHENTI, ALBERTO, Sull’ autolisi delle sostanze vegetali. III. Con- tributo allo studio degli enzimi proteolitici nei semi non germinanti.. Abst. in Zent. Biochem. und Biophysic. 14:141. 1912. , Nuovo contributo allo studio degli enzimi proteolitici nei semi non germinanti. Abst. in Zent. Biochem. und Biophysic. 14:61. 1912. Brown, ADRIAN, the existence of a semipermeable membrane ea the seeds of some of the Gramineae. Ann. Botany 21:79- 87. 190 10. 4 The selective permeability of the covering of the seeds of Hordeum vulgare. Proc. Roy. Soc. London B 81:82-93. 1909. , and Wortey, F. P. The influence of temperature on the absorp- tion of water by seeds of Hordeum vulgare in relation to the temperature coefficient of chemical change. Proc. Roy. Soc. London B 85 :546-553. 1912. 12, Brown, Horace T., and Morris, Harris, Untersuchungen iiber die Keimung einiger Griser. Zeitschr. — Brau. 13:375-380, 393-399, 417-429, 437-451, 477-481, 489-494. 13. Brown, Horace T., Die Ss Beachailesheit der Gerste vom esiesisclirtclodetes Standpunkt. Zeitschr. Gesells. Brau. 30: 255-259: 14. CANNON, eG Austin, A morphological study of the flower and embryo of the wild oat, Avena fatua L. Proc. Cal. Acad. III. 1:329-355. bls. 49-53. 1900 15- Couprn, Henri, Recherches sur l’absorption et le rejet de l’eau par les graines. Ann. Sci. Nat. Bot. VIII. 2:129-222. 16. CripptE, Norman, Wild oats and false wild ae tet nature and dis- tinctive characters. Canada Dept. Agric. S. Bull. 7. pp. 11. pls. 4. Igr2. 17. CROCKER, WILLIAM, The réle of seed coats in delayed germination. Bor. GAZ. 42:265-291. 1906. , Germination of the seeds of water plants. Bor. GAz. 44:375-380. wT ? 19. acne W., Uber die Entstehung stirke fea Fermente in den Zellen Sadana Pflanzen. Bot. Zeit. 41:601-606. 20. Dewey, Lyster H., Migration of weeds. eat aee U.S. Dept. Agric. 277. 1896. 21. Duvet, J. W. T., Preservation of seeds buried in the soil. Bot. Gaz. 37:146-147. 1904. 412 BOTANICAL GAZETTE [May 22. ECKERSON, SoputA, A physiological and chemical study of after-ripening. ot. Gaz. 55:286-299. 1913. 23. Fawcert, H. S., The vitality of various weed seeds with different methods of treatment a) investigations of their rest period. Proc. Iowa Acad. Sci. 1§:25-45. 1908. 24. FisHer, ALFRED, Wasserstoff und caetatgggpa als Keimungsreize. Ber. Deutsch. Bot. Gesells. 25:108-122. 1907. 25. Gassner, Gustav, Uber Keimungatingungn einiger siidamerikanischer Gramineensamen. Ibid. 28:350-364. 1 , Uber Keimungsbedingungen jonas siidamerikanischer Grami- neensamen. Ibid. 28:504-512. 1910. , Vorlaufige Mitteilung neuerer Ergebnisse meiner Keimungsunter- suchungen mit Chloris ciliata. Ibid. 29:708-722. 1912. 28. , Untersuchungen iiber die Wirkung des Lichtes und des Tempera- turwechsels auf die Keimung von Chloris ciliata. Jahrb. Hamburg. Wis- senschaft. Anstalten 29:1-120. 1911. 29. GREEN, J. REYNOLDS, On the germination of the castor oil ee Proc. Roy. Soc. London B. 48:370-392. 1890. 30. Gris, A., Recherches sur la seecinbankioin: Ann. Sci. Nat. Bot. V. 2:5-123- 1864. 31. Griiss, J., Beitriige zur Physiologie der Keimung. Landw. — 25: 385-452. I 32. GuERIN, P., Wececcies sur le development du tégument aise et du pericarpe des graminées. Ann. Sci. Nat. Bot. VIII. 9:1-59. 1899- 33- GUMBEL, HERMANN, Untersuchungen tiber die oe verschiedener Unkrauter. Landw. Jahrb. 43:215-321. 34. Hawkins, Lon A., The porous sige ty for the care watering of plants. Plant World 13 1220-227. 35. HEInRICHER, E., Die ies se eal das Licht. Ber. Deutsch. Bot. Gesells. ahh: ea: 1908. ———., Samenreife und Samenruhe der Mistel (Viscum album L.) und die ‘Cmatiinds welche die Keimung beinflussen. Anz. Ksl. Akad. Wiss. Wien, Math.-Naturw. Kl. 17:258-259. 1912. 37- Horrer, E., Uber die Vorginge bei der Nachreife von Weizen. Landw. VecsuchaSeat. 402356-364. 1892. 38. JANSON, C., Untersuchungen iiber die Einlagerung der Reservestoffe in die Hafer- und Gerstenkirner beim Reifungsprozess. Abst. in Bot. Centralbl. 110:454. 1909. 39- JOHANNSEN, W., Studier over Planternes periodiske Livsyttringer- 1. Om antagonistiske Virksomheder i Stofshiftet sirlig under modning 8 Hoile. Abst. Bot. Jahrb. 25:143. 1897. 40. JUNITZKEY, MELLE N., Respiration anaerobie des graines en germination. Rev. Gén. Botanique 19:208-220. 1907. . Kiesstinc, L., Untersuchungen tiber die —— der Getreide. Landw. jaime (Saves 13449-514. 1911. 26. 27- 1914] ATWOOD—GERMINATION OF AVENA 413 42. Kiyzet, W., Uber die Keimung halbreifer es bag Samen der Gattung Cuscuta. ance: Versuchs-Stat. 54:125-13 , Uber den Einfluss des Lichtes auf “die Kelme. - “Lichtharte” Samen. Ber. Deutsch. Bot. Gesells. 25:269-276. 1907. , Die Wirkung des Lichtes auf die Keimung. Ibid. 26*:105-115. 1908. , Lichtkeimung. Einige bestitigende und erginzende Bemerkungen zu den vorlaiufigen Mitteilungen von 1907 und 1908. Ibid. 26*:631-645. 1908. , Lichtkeimung. Erliuterungen und Erginzungen. Ibid. 27:536- 545. 1909. 47. LEHMANN, Ernst, Uber die Beeinflussung der Keimung lichtempfindlicher Samen durch die Temperatur. Zeitschr. Bot. 4:465-529. 1912. 48. , Einige neuere Keimungsarbeiten. Sammelreferat. Jbid. 5:365- 377- 1913. 49. , und Ottenwalder, A., Uber katalytische Wirkung des Lichtes bei der Keimung lichtempfindlicher Samen. Jbid. 5:337-364. 1913. 50, Lepescuxin, W. W., Uber die osmotischen Eigenschaften und den Turg- 58. 59- 60. ordruck der lsttnelenksetien der Leguminosen. Ber. Deutsch. Bot. Gesells. 26*: 231-237. 1908. Moneratl, O., and Zapparoui, T. V., The influence of alternations of humidity and dryness on the germination of seeds in the case of some weeds. Malpighia 24:313~-328. 1912. Nitsson-Euxte, H., Uber Fille spontanen Wegfallens eines Hemmungs- faktor bei WHafer. Zeitschr. Ind. Abst.- und Vererbungsl. 5:1-37. IQII. PamMet, L. H., The delayed germination of seeds. Rep. Brit. Assoc. Adv. Sci. (Winnipeg) 673-674. 1 , and Kinc, Cuartotre M., Delayed germination. Proc. Iowa Acad. Sci. 1'7:20-33. 1910. PUGLIESE, ANGELO, Sull ’autolisi delle sostanze vegetali. Nota IV. La fahigkeit und Atmungsintensitét. Jahresb. Verein Angew. Bot. 4:70- 87. 1906. - REICHARD, ALBERT, Der Gerbstoff in der ene des Gerstenkornes. Zeitschr. Chem. und Indus. Kolloide 10:214-219. 19 Ricuarps, H. M., The respiration of wounded stink: Ann. Botany T0:531-582. 1806. Scuréper, H., Uber die selectiv permeable Hiille des Weizenkornes. Flora 102:186~208. 1911. SHULL, CHARLES ALBERT, The oxygen minimum and the germination of Xanthium seeds. Bor. Gaz. §2:453-477. 1911. , Semipermeability of seed coats. Bor. Gaz. 56:169-199. 1913. 414 BOTANICAL GAZETTE [MAY 62. StrcH, Conrap, Die Atmung der Pflanzen bei verminderter Sauerstoff- spannung und bei Verletzungen. Flora 74:1-57. 1891. 63. STOWARD, F., oa eer respiration in certain seeds. Ann. Botany _ 222415-448. I 64. Traput, M., ae — de V’origine des avoines cultivées. Compt. Sead, 149:227-220. 65. VaN TIEGHEM, Pu., Ge hniches, iis deleaiciiies sur la germination. Ann. ci. Nat. Bot. V. 17:205-224. 1873. 66. Vouen, A., Flughafer. Jahresb. Verein Angew. Bot. 6:290-294. 1908. 67. ZAD z, ADOLPE, Der Flughafer. Inaug. Diss. Jena. pp. 1-48. 19009. 68. mire W., Zur Kenntnis der — in reifenden Samen. Beih. Bot. Genteuibt: 27:63-82. IgII. UNDESCRIBED PLANTS FROM GUATEMALA AND OTHER CENTRAL AMERICAN REPUBLICS XXXVITE JoHN DONNELL SMITH Erysimum Ghiesbreghtii Donn. Sm.—Folia linearia apice calloso acuta deorsum angustata parce calloso-denticulata. Sepala pedicellis bis longiora, lateralia basi saccata. Petala obovata in - unguem filoformem attenuata, lamina purpurea. Ovarium acute tetragonum, stylo brevi, stigmate bilobo. Caules ex eodem rhizomate pluries simplices stricti 4-7 dm. longi rubes- centes foliorum costa decurrente striati cum foliis racemo sepalis ovario pube bipartita plus minus strigillosi. Folia inferiora approximata 5—7.5 cm. longa m: lanceolata 10-12 mm. longa 3 mm. lata costata, lateralia in saccam 1.5 mm. ongam producta. Petala 16 mm. longa, lamina 6 mm. lata saturate purpurea nervosa. Stamina 12 mm. longa. Pistillum petalis aequilonga, stylo 2 mm longo, stigmate 1.5mm. lato. Siliqua 3.7 cm. longa, valvis reploque carinatis, seminibus uniseriatis 12-15 immarginatis. Inter saxa ad declivitates montis, Chiapas, Mexico, Aug. 1864-1870, August Ghiesbreght, n. 817.—Inter San Marcos et Ostuncalco, Depart. Que- zaltenango, Guatemala, alt. 3000 m., Jun. 1882, F. C. Lehmann, n. 1510. Xylosma chloranthum Donn. Sm.—Spinosum glabrum. Folia lanceolata tenuiter caudato-attenuata basi acuminata crenato- glandulariserrata nitida. Flores feminini umbellato-fasciculati pedunculis medio articulatis paulo longiores. Sepala 4 herbacea pistillo triente breviora. Ovarium tetragynum. Frutex ad truncum ramosque vetustos spinis digitalibus compositis fuscis uti rami crebre lenticellato-punctatis armatus, ramulorum superiorum vir- gatorum spinis raris simplicibus tenuibus 6-8 mm. longis. Folia pergamen- tacea concoloria supra vernicoso-lucida 12-15 cm. longa 3-4 cm. lata ad caudam integra, nervis lateralibus utrinque 6-7, petiolo 5-7 mm. longo canali- culato. Pedunculi indefiniti 2-2.5 mm. longi, bracteis basalibus coacervatis Squamiformibus ovatis o. 5-1 mm. longis margine puberulis. Sepala ex cl. Tepertore viridia ovata 2 mm. longa apice ipso puberula ceterum uti pistillum * Continued from Bor. Gaz. 56:62. 1913. 415] [Botanical Gazette, vol. 57 416 BOTANICAL GAZETTE [MAY glabra. Discus leviter crenatus. Ovarium ellipsoideum 2 mm. longum stylo bis longius, placentis 4 biovulatis, stigmatis lobis hippocrepiformibus. Flores masculini et baccae deficientes Cubilquitz, Depart. Alta Verba Guatemala, alt. 350 m., Apr. 1913, H. von Tuerckheim, n. 4111. Sloanea (§ EvsLoANEA K. Schum.) Tuerckheimii Donn. Sm.— Folia ovalia basi acuminata subtus puberula. Racemi singuli sim- plices, rhachi gracili, pedicellis filiformibus, superioribus 2-3-nis. Stamina sepalis dimidio longiora, antheris quam filamenta bis bre- vioribus inappendiculatis rima apicali dehiscentibus. Discus intra torum staminalem nullus. Pistillum calyce bis fere longius. rbor, ramulis petiolisque teretibus, novellis fulvo-velutinis, denique pubescentibus. Stipulae caducae ignotae. Folia nascentia fulvo-velutina, adulta supra glabra 24-31 cm. longa 13.5-17.5 cm. lata cuspide deltoidea 5-8 mm. longa apiculata in angulum subrectum deorsum desinentia ad apicem versus obscure sinuato-dentata, nervis lateralibus utrinque 11-13 ante mar- ginem anastomosantibus, venis transversis inter se summum 7 mm. distanti- bus, petiolis 4. 5-6 cm. longis apice incrassatis. Racemi ad nodos plerumque defoliatos approximatos siti 8-13 cm. longi pubescentes, pedicellis 1. 5-3-5 cm. longis, bracteis bracteolisque lanceolatis 3-5 mm. longis, floribus 1 cm.- diametralibus. Sepala 5-8 sublibera valvata oblongo- vel lanceolato-ovata circiter 4 mm. longa extus pubescentia intus fere glabra, maximo sepius 3-fido. rus staminalis orbicularis 3 mm.-diametralis foveolatus. Stamina 6 mm. rae antheris oblongo-ellipticis 2 mm. longis breviter apiculatis, filamentis patenter pubescentibus. Ovarium tetragono-ovoideum 2.5 mm. altum pi- losum, stylo’ad 1 mm. pantie o. Capsula juvenilis ellipsoidea 1 cm. longa 0.5 cm. lata spinis 9 mm. longis puberulis setosa, matura ignota. —S. multi- florae Karst. valde affinis. In silvis ad Cubilquitz, Depart. Alta Verapaz, Guatemala, alt. 350 M., Mart. et Maj., 1913, H. von Tuerckheim, n. 4157. Ilex (§ Eurrex Loesn.) costaricensis Donn. 5m. —Glabra. Folia elliptica breviter acuminata in petiolum angustata et decur- rentia coriacea lucida impunctata subtus subtiliter glandulosa integra margine revoluta. Pedunculi solitarii 1- ~2-3-flori, flori- bus iso-pentameris. Ovarium ovoideum, spgmatibus sessilibus in hemisphaerium coalitis, loculis uniovulatis. Ramuli annotini densissime foliati et pedunculi et pedicelli sulcato- angulati. Folia 4.5~6.5 cm. longa 2.5~-3.5 cm. lata, nervis lateralibus for- tioribus utrinque 7-8, petiolis 1. 5—2 cm. longis canaliculatis, stipulis squamae 1914] SMITH—PLANTS FROM CENTRAL AMERICA AI] formibus deltoideis minutis. Pedunculi axillares vel superiores extra-axillares 8-14 mm. longi, pedicellis singulis vel 2-3-nis 6-8 mm. longis, bracteis stipulae-formibus, floribus tantum femininis notis. Calycis partiti lobi semi- — 1mm. longi. Petala subquadrata 3.5 mm. longa atque lata usque ad 1 . fere connata. Antherae cassae orbiculares, 1 mm.-diametrales Riaetie: aii longiores. Ovarium 2 mm. longum stigmatum hemisphae- rio bis longius. Drupa deficiens.—I. mexicanae (Turcz.) Benth. et Hook. quoad inflorescentiam proxima videtur. Cuesta dela Cara, haud procul ab El Péramo, Comarca de Puntarenas, Costa Rica, Jan. 1897, H. Pittier, n. 10843. Connarus brachybotryosus Donn. Sm.—Foliola 3 elliptica vel ovato-elliptica cuspidato-acuminata apice ipso obtusa basi rotun- data bis longiora quam latiora nitida. Racemi fasciculati petiolo breviores. Sepala petalis paulo breviora staminibus longioribus 3-plo longiora pistillo aequilonga. Arbor. Folia glaberrima petiolo 6-8 cm. addito 2. 5-3 dm. longa, foliolis i.5-2 dm. longis coriaceis, nervis lateralibus fortioribus utrinque 5 subtus elevatis. Racemi paucifasciculati 4-5 cm. longi cum sepalis ferrugineo- pubescentes, pedicellis 2-3 mm. longis, floribus ex cl. repertore luteo-viridibus. Sepala discreta oblongo-ovata 3 mm. longa. Petala obovato-oblonga 4 mm. longa 1.5 mm. lata glabra. Stamina longiora 1 mm. longa, breviorum antheris subsessilibus. Ovarium lanceolato-ellipsoideum 1.5 mm. longum cum stylo aequilongo appresse pilosum, stigmate 5-capitellato. Capsula ignota. In silvis ad Cubilquitz, Depart. Alta Verapaz, Guatemala, alt. 350 m., Febr. 1913, H. von Tuerckheim, n. 4027. DALBERGIA VARIABILIS Vog., var. cubilquitzensis Donn. Sm.— Petiolus communis usque ad 2 dm. longus, foliolis oblongis 8. 5 cm. longis 3-plo et ultra longioribus quam latioribus. Cymae fusco- pubescentes 6.5 cm. latae. Stamen vexillare deficiens. Ovarium vacuum. Cubilquitz, Depart. Alta Verapaz, Guatemala, alt. 350 m., Febr. 1913, H. von Tuerckheim, n. 4001. Drepanocarpus (§ RETICULATI Benth.) costaricensis Donn. Sm. —Stipulae triangulares spinescentes. Foliola 9-15 oblonga vel elliptica apice late acuta mucronulata basi rotundata supra ara- neosa subtus fulvo-tomentosa. Flores sessiles, bracteolis calycis duas partes cingentibus. Calycis dentes superiores late rotundati, inferiores anguste triangulares. Vexillum crassum extus sericeum. Stamina iso-diadelpha. 418 BOTANICAL GAZETTE [MAY Ramuli juniores cum stipulis petiolis foliolorum pagina inferiore paniculis fulvo-tomentosis, bracteolis calyce vexillo fulvo-sericies. Stipulae 5 mm. longae deciduae. Petiolus communis 10. 5-13 cm. longus, foliolis reticulato- nervosis plerumque oblorigis 4.5-7.5 cm. longis 1.5-2.5 cm. latis, inferiori- bus cujusque folii decrescentibus magis ellipticis 3 cm. longis 2 cm. latis, terminali maximo obovato-oblongo. Paniculae in exemplis mancis solum suppetentibus axillares singulae folia superantes, bracteolis subsemiorbicu- aribus 4 mm. longis persistentibus, floribus 11 mm. longis. Calyx 6 mm. longus, dentibus 2 mm. Jongis, superioribus 3 mm. latis. Vexillum subcoriaceum suborbiculare 9 mm. longum atque latum alis aequilongum. Stamina carmam cucullatam 7 mm. longam aequantia, vagina jam in alabastro utrinque Uaqee ad basin fissa. Ovarium basi disco cupulari cinctum leviter incurvum vil- losum uniovulatum, stylo brevissimo. Legumen deficiens—Ad. D. salva- dorensem Donn. Sm. floris indole accedens foliis praesertim recedit. Santiago prope San Ramon, Prov. Alajuela, Costa Rica, alt. 1000-1 100 Hiss Jun. 1901, Amando Brenes, n. 14507.—Typus in herbario Musei Nationalis sub numero proprio 861757 servatur. Lonchocarpus santarosanus Donn. Sm.—Foliola 13-15 lanceo- lato- vel oblongo-ovata apice tenuiter acuminata basi acuta vel obtusa impunctata. Pedicelli approximati solitarii biflori pedi- cellis propriis additis florem subaequantes. Vexillum subsemior- biculare pubescens. Alae et carina rectae exauriculatae. Ovarium biovulatum demum monospermum. Arbor 6-8-metralis, ramulis novellis petiolulis folioloram subtus nervis pedicellis calyce ferrugineo-pubescentibus. Petiolus communis 13-18 ¢™- longus glabrescens. Foliola plerumque 6-juga 4.5-6.5 cm. longa 2-2-5 (™ lata chartacea supra glabra subtus pubescentia, nervis lateralibus utrinque 5-6, petiolulis 4-5 mm. longis. Racemi 6-9 cm. longi supra medium florifer, pedicellis communibus circiter 4 mm. longis raro 3-floris, pedicellis props 2-3 mm. longis infra apicem bracteolatis, bracteis bracteolisque orbicularibus vix 0.5 mm. longis caducis. Calyx late campanulatus 2 mm. longus tube catus. Petala coccinea, vexillo 6 mm. longo latiore quam longiore basi latis- sime acuto prope unguem transverse bicalloso, alis carimaque late oblongis asi truncatis. Tubus stamineus 4 mm. longus.’ Ovarium pubescens. Legumen mihi non visum, Mataquescuintla, Depart. Santa Rosa, Guatemala, alt. 1 560 m., Mart. 1894, Heyde et Lux, n. 6328 ex Pl. Guat. etc. quas ed. Donn. Sm. = CAESALPINIA BONDUCELLA Fleming, var. urophylla Donn. co Petiolus communis 2 dm. longus glaber seta terminatus, ie jas 7-jugis oblongo-ellipticis 6-8. 5 cm. longis 3-3.5 cm. latis cau 1914] SMITH—PLANTS FROM CENTRAL AMERICA 419 acuminatis seta mucronatis basi rotundatis chartaceis nitidis. Racemus axillaris 22 cm. longus, bracteis patentibus 5 mm. longis, floribus 1.5 cm. longis submasculinis. Calycis tubus obliquus sulcatus 7 mm. longus, segmenta 8-1o mm. longa. Petala nigro- nervosa. Filamenta infra medium villosa.—Exemplum unicum mihi visum quamquam imperfectum varietatem tamen insignem vel forsitan speciem novam constituere videtur. Ad collem San Isidro prope San Ramén, Prov. Alajuela, Costa Rica, alt. 1300 m., Jul. 1901, Amando Brenes, n. 14501.—Typum in herbario Musei N: SGtomalin sub numero proprio 861756 vidi. Leucaena Shannoni Donn. Sm.—Pinnae 4-5-jugae, foliolis g-15-jugis oblongis apice rotundato mucronulatis basi rotundatis inaequilateralibus binerviis, superioribus obovato-oblongis basi gibboso-obliquis, petiolo sicut pinnarum rhachis prope apicem glandula oblonga munito. Racemus terminalis — pedun- culis 2-5-nis, floribus glabris. Petiolus communis 6-8. 5 cm. longus teres pubescens. Pinnarum rhachis 6-10 cm. longa lineis duabus pubescentibus a foliolis decurrentibus angulata. Foliola 15~22 mm. longa 5-8 mm. lata pubescentia vel glabrescentia utrinque conspicue nervosa. Racemus 2-4 dm. longus crassus aphyllus glabrescens glanduligerus, pedunculis 12-22 mm. longis pubescentibus apice vel inf apicem bracteis quaternis minutis instructis, capitulis absque staminibus I cm. -diametralibus. Calyx turbinatus 2 mm. longus. Petala spatulato- lanceolata 3 mm. longa. Stamina 6 mm. longa, antheris oblongis 1 mm. longis. Stylus 2 cm. longus. Legumen haud satis maturum tantum visum breviter (8 mm.) stipitatum ro cm. longum 12 mm. latum utrinque acumina- tum suturis pubescens, seminibus oblique transversis. Cojutepeque, Henast. Cuscatlin, Salvador, alt. goo m., Dec. 1892, W. C. Shannon, n. 5032 ex Pl. Guat. etc. quas ed. Donn. Sm.—Eadem planta a C. B. Doyle ad Rosario, Chiapas, Mexico, Dec. 1906 lecta, sub numero 87* distri- buta, in herbario Musei Nationalis numero proprio 574705 signata exstat. Pithecolobium (§ SamMANnEA Benth.; Parviflora Benth.) adinocephalum Donn. Sm.—Pinnae 1-2-jugae, foliolis 3-5- jugis lanceolato- vel ovato-oblongis apice ipso obtusis basi acutis centrali-costatis coriaceis supra nitidis subtus puberulis pallidioribus, glandula infra medium petioli oblonga inter foli- ola parium 1-2 superiorum scutelliformi. Panicula densissime capitulifera, pedunculis radiatim fasciculatis, floribus pedicellatis. 420 BOTANICAL GAZETTE (May Arbor inermis, coma rotundata, ramulis teretibus glabris. Petiolus com- munis 2-7 cm. longus cum pinnis 4-7 cm. longis tetragonus glaber, foliolis _ 2.5-4.5 cm. longis 1-2 cm. latis, nervis lateralibus late patentibus, venis supra conspicuis minute reticulatis. Panicula terminalis 10-14 cm. longa, striatis, infimis 6-9 cm. longis erecto-patentibus, pedunculis 3-6-fasciculatis gracilibus 1.5-2 cm. iisigis puberulis, capitulis absque staminibus 7 mm diametralibus, pedicellis 1 mm. longis puberulis. Calyx campanulatus 1 mm. longus puberulus. Corolla infundibuliformis 3 mm. longa. Stamina in tubum inclusum connata 8 mm. longa. Legumen junius solum visum rectum planum glabrum 1.5 dm. longum 2 cm. latum, seminibus circiter 13.—Gabi- loncillo incolarum. Ad fundum La Verbena prope Alajuelita, Prov. San José, Costa Rica, alt. tooo m., Ad. Tonduz; Aug. 1894, n. 8932; Dec. 1894, n. 9077.—In silvis col- linis, Peninsula Nicoya, Costa Rica, Jan. 1900, Ad. Tenduz, n. 13531- Guamatela Donn. Sm., nov. gen. RosACEARUM e tribu SPI- RAEEIS Focke.—Flores hermaphroditi. Calycis persistentis tubus brevis, segmenta 5 imbricata. Petala 5 ori calycis inserta. Sta- mina 10 uniseriata segmentis calycinis et petalis opposita, fila- mentis liberis, antheris cordato-ovatis apiculatis. Discus tubum calycis vestiens concavus margine integro petala et stamina ferens. Carpidia 3 sessilia ope stigmatorum primum connata demum libera, stylis terminalibus, stigmatibus capitellatis, ovulis pluribus suturae ventrali biseriatim affixis ascendentibus. Carpidium seminife- rum unicum membranaceum sutura ventrali dehiscens, seminibus pluribus obovoideis exalbuminosis, testa ossea nitida.—Frutex reclinans. Folia opposita simplicia cordato-ovata serrulata palma- tinervia. Stipulae liberae setaceae. Racemi terminales, bracteis filiformibus, floribus sanguineis.—Genus foliis oppositis in Spiraeets anormale.—Nomen ope metatheseos syllabarum patriam significat. Guamatela Tuerckheimii Donn. Sm.—Folia supra glabra viti- dia bullata subtus niveo-tomentosa 5—7-nervia. Racemi singuli vel bini, pedicellis alternis, inferioribus saepe 3-floris. Calycis segmenta oblongo-ovata acuta. Petala oblongo-elliptica et sta- mina calyce breviora. Carpidia lanceolato-ovoidea, duobus tertio jam sub anthesi paulo minoribus denique vacuis marcidis. Folli- culus subovalis inflatus, stylo incurvo. Caulis ramosus, ramulis petiolis foliorum utrinque nervis fusco-pubes- centibus. Stipulae 2-4 mm. longae. Folia longe —— acuminata 4.5-9 cm. longa 2.5-5.5 cm. lata, adem 0.52.5 cm. longis. Racemi 1914] SMITH—PLANTS FROM CENTRAL AMERICA 421 adjecto pedunculo 2.5-4 cm. longo 9-10 cm. longi niveo-tomentosi circiter to-16-flori, pedicellis 4-5; mm. longis, bracteis binis 6-8 mm. longis. Calycis sanguinolenti tubus 2 mm. longus, segmenta 7 mm. longa striata utrinque incana. Petala 5 mm. longa vix unguiculata nervosa utrinque pubescentia. Filamenta 4 mm. longa e basi superne decrescentia, antheris aegre I mm seminibus circiter 11-12 imbricatis 1. 2 mm. longis atque crassis. n silvis montanis prope Purulha, Depart. Baja Verapaz, Guatemala, alt. 1750 m., Oct. 1912, H. von Tuerckheim, n. 3903. Rubus ($ Evsatus Focke.) leptosepalus Donn. Sm.—Foliola quinata orbiculari-ovalia acute caudato-acuminata basi rotundata, ternata ovato- vel obovato-elliptica acuminata basi obtusa vel acuta. Paniculae angustae nutantes laxiflorae superne simpliciter foliatae, bracteis setaceis perlongis. Sepala lineari-lanceolata setaceo-appendiculata petalis suborbicularibus aequilonga. Rami digitulum crassi subtetragoni sulcati glandulifero-setosi cum ramulis petiolis petiolulis paniculis glandulifero-pilosis recurvo-aculeati rubiginoso- Pubescentes. Stipulae petiolares setaceae 10-12 mm. longae. Foliorum inferiorum foliola quinata 10-14 cm. longa 5.5-8.5 cm. lata argute duplo- serrata membranacea supra glabrescentia subtus pubescentia nervo medio aculeata, petiolis 7-8 cm. longis, —— — 4.5 cm. longo, extimis 12 mm.longis. Foliorum foliola ternata 6-10. 5 cm. longa 3-5 cm. lata, petiolo 1-2 cm. ei petiolulis eas. mm. aoe Ramuli floriferi erecto- P Sepala appendicula 4-s; mm. longa computata 1.5-1.7 cm. longa utrinque eglandulosa inermia. drs ex cl. DOR rosea. Recep- lum ovideum 4 mm. longum numerosa glabra. Fructus hae —R. adenotricho Schlecht. habitu pita sepalis praesertim differt. Coban, Depart. Alta Verapaz, Guatemala, alt. 1350 m., Jul. as H. von Tuerckheim, N. 2452. Gilibertia leptopoda Donn. Sm.—Folia integra lanceolata vel lanceolato-elliptica tenuiter acuminata basi acuta. Umbellae erminales racemosae, pedunculis paucis longissimis filiformibus inarticulatis nudis, pedicellis paucis elongatis, floribus 5—6-meris. Calyx turbinatus margine subinteger. Petala triangulari-ovata Staminibus paulo longiora. 422 BOTANICAL GAZETTE [May Arbor. Folia 10. 5-13 cm. longa 3.5-4 cm. lata pergamentacea rubro- punctulata, nervis lateralibus fortioribus utrinque 7-8 et venis inconspicuis, petiolis summum 4 cm. longis. Racemi rhachis 2-3 cm. longa, pedunculis sub insertione pedicellorum vix dilatatis, pedicellis 3-8-nis 14-16 mm. longis, bracteis bracteolisque vix ullis. Calyx 2 mm. longus in pedicellum attenuatus. etala 1.5 mm. longa apiculata striata. Antherae orbiculares 1 mm. longae filamenta aequantes. Discus leviter convexus. Styli in conum brevissimum fere connati. Fructus non suppetit.—Secundum clavem specierum Centrali- Americanarum in Bor. Gaz. 55:436. 1913 adumbratam haec juxta G. Roth- schuii Harms locanda discrepat inter alia umbellis paucifloris. In silvis montanis prope Coban, Depart. Alta Verapaz, Guatemala, alt. 1550 m., Jan. 1913, H. von Tuerckheim, n. 4166. Faramea (§ TETRAMERIUM DC.) cobana Donn. Sm.—Folia lanceolata apice ipso obtusa basi acuminata. Stipulae triangulares aristulatae costa decurrentes. Pedicelli in axibus superioribus fasciculati pedunculo vix ullo insidentes floribus subaequilongi. Calycis eglandulosi limbus denticulatus tubo 3-plo_ brevior. Corolla triente lobata. Antherae inclusae. Bacca globosa eco- stata. Fruticulus metralis totus glaberrimus, ramulis decursu stipularum 1 bicari- nato-angulatis. Folia 5.5-7.5 cm. longa 13-21 mm. lata pergamentacea opaca, costa utrinque prominente, nervis lateralibus patulis utrinsecus 9-11, longam sensim productis. Pedunculus 1-2 mm. longus, pedicellis 2-3-nis filiformibus 12 mm. longis. Calyx 2 mm. longus, tubo turbinato, limbo urceo- lato, denticulis minutis. Corolla (nondum satis aperta solum visa) 12 mm. longa ex schedula coerulea, tubo gradatim dilatato infra medium staminigero, lobis oblongo-ovatis. Antherae subsessiles prope basin affixae 4 mm. longae. Discus limbum calycinum aequans. Stylus 7 mm. longus. Bacca 9 mm< diametralis saturate atricolor ex cl. repertore, semine sphaerico 6 mm.-diame- trali basi profunde excavato, albumine cyaneo.—Juxta F. pedicellarem Muell. Arg. locanda, - In silvis montanis oppido Cobén vicinis, Depart. Alta Verapaz, Guatemala, alt. 1550 m., Jul. 1912, H. vom Tuerckheim, n. 2474. Farameae clavis specierum Centrali-Americanarum. Sect. I. HypocHasmMaA Muell. Arg. A. Folia penninervia. 3. Calyx denticulatus:..- 3... F. salicifolia Presl. 2. Calyx inaequaliter lobatus.......... F. eurycarpa Donn. ess 1914] SMITH—PLANTS FROM CENTRAL AMERICA 423 B. Folia trinervia. 4. Pola auriculata so. 5 2% F. trinervia K. Schum. et Donn. Sm. o> Folia bast acttas =: 66 Seis eee F.. suerrensis Donn. Sm. Sect. Il. Terramerium DC. A. dehorescentia coryniboss. =. 6. es F. odoratissima DC. B. Inflorescentia fascicularis: ....... 2.0.0... F. cobana Donn. Sm. Jacquemontia (§ CymosaE Meissn.) platycephala Donn. Sm.— Folia cordato-ovata supra glabra subtus minute strigillosa. Pedun- culi folia non aut parum superantes. Cyma transversim oblongo- capituliformis compacti-flora imbricato-bracteosa fusco-villosa, bracteis extimis orbicularibus, interioribus oblongo-obovatis. Sepala elliptica acuminata bracteis intimis triente corolla triplo breviora. Volubilis, caulibus petiolis pedunculis appresse pilosis vel glabrescentibus. Folia 6.5-7.5 cm. longa 4-5 cm. lata mucrone apiculata, nervis lateralibus utrinque 8-9 subtus conspicuis usque ad marginem distinctis, es a 2.5 cm. longis. Pedunculi 9-13 cm. longi. Cyma (nondum profecto evoluta tantum visa) corollis neglectis 2.5-3 cm. alta 7-9.5 lata, ramis lateralibus brachiatis elongatis, intermedio vix ullo, floribus numerosis subspicatis secun- dis, bracteis uti sepala extus fusco-villosis intus glabris nigricantibus, extimis duabus 18-20 mm .diametralibus, interioribus pluribus 17-z0 mm. longis 8-10 mi. latis. Sepala cymbiformia 12-13 mm. longa 6~7 mm. lata. Corolla 38 mm. longa ad plicas fusco-villosa ex schedula alba. Stamina ad 10 mm. supra basin corollae inserta 12 mm. longa, antheris 4 mm. longis. Ovarium pilosum, Stylo 18 mm. longo, stigmate capitato-bilobo. Capsula ignota.—Ipomoeae hirtiflorae Mart. et Gal. et I. Perryanae Duchass. et Walp., speciebus ambabus ob inflorescentiam ad Jacquemontiam melius ascribendis, nostra valde affinis videtur. Cubilquitz, Depart. Alta Verapaz, Guatemala, alt. 350 m., Apr. 1913, H. von Tuerckheim, n. 4133. a & Cyphomandra aculeata Donn. Sm.—Omnibus in partibus glabra. Folia solitaria lanceolato-oblonga utrinque acuminata, costa subtus et petiolo aculeatis. Cyma pauciflora. Corolla calyce .3-plo longior rotata. Stamina recta basi connata, fila- mentis brevibus. deorsum dilatatis, connectivo sub antherae apice evanido. Stylus filiformis, stigmate clavato. Folia in ramulo unico suppetente 8-10.5 cm. longa 2.3-3 cm. lata char- tacea, nervis lateralibus utrinsecus 7-8, petiolis 11-14 mm. longis, aculeis minutis recurvis. Cymae unicae vistae pedunculus 4 cm. longus, axes pri- 424 BOTANICAL GAZETTE [MAY mariae 7-10 mm. longae, pedicelli 2. 5-3 cm. longi, flores 4 circiter 22 mm. longi. Calyx 7 mm. longus, lobis 3 mm. longis semiorbicularibus. Corollae tubus 4 mm. longus, segmenta anguste oblonga 15-16 mm. longa basi 4 mm. lata superne sensim acuteque angustata crassa. Stamina 14 mm. longa in annulo 2 mm. longo connata, filamentis 3 mm. longis triangularibus, antheris anguste oblongis 9 mm. longis, connectivo crasso 2 mm. lato ecalloso. Stylus 6mm. longus. Bacca ignota. Prope Coban, Depart. Alta Verapaz, Guatemala, Apr. 1882, F. C. Lehmann, Nn. 1334. Brachistus meianthus Donn. Sm.—Omnibus in partibus praeter corollam et stamina glaberrimus. Folia attenuato-acuminata in petiolum oblique attenuata gemina, altero lanceolato-elliptico, altero 2-3-plo minore rhomboideo-ovato. Flores 4~5-metl. Calyx integer. Corollae segmenta tubo intus pubescente bis longiora extus puberula. Antherae cordiformes filamenta pube- scentia subaequantes. Bacca coccinea. : Fruticosus, ramulis teretibus. Folia membranacea pellucida minute punctulata integerrima, altero 11-15 cm. longa 3. 5-5.3 cm. lata petiole 1.7- 2.1 cm. longo, nervis lateralibus utrinque 5-6 sicut venae transversae remotae subtus conspicuis, altero 3. 5-6 cm. longo 2-3 cm. lato, petiolo 3-6 mm. longo. Pedunculi pluri-fasciculati nonunquam semel dicotomi, floriferi 12 mm. longi, fructiferi 15 mm. longi. Calyx hemisphaericus 1 mm. altus. Corolla 5-6 mm. longa ex schedula flavicans, tubo ad insertionen, staminum pubescente, segmentis oblongo-ovatis. Stamina 4 mm. longa, antheris acutis. Stylus corollam paulo superans. Bacca calyci immutato insidens globosa 6-7 mm. diametralis—B. hebephyllo Miers. proximus. Pansamala, Depart. Alta Verapaz, Guatemala, alt. 1250 m., Febr. 1887, H. von Tuerckheim, n. 1134 ex Pl. Guat. etc. quas ed Donn. Sm.—In silvis ad Panzal, Depart. Baja Verapaz, Guatemala, alt. 1350 m., Oct. 1912, tatbicted Tuerckheim, n. 3936. Columnea (§ EvcotumNneA Hanst.) cobana Donn. Sm.—Valde anisophylla. Folia subsessilia lanceolato-oblonga vel -elliptica attenuato-acuminata basi inaequali acuta supra glabra subtus nervis marginibusque pilosa ceterum sparsim strigillosa. Pedun- culi folio majore paulo breviores. Calycis segmenta attenuato- ovata dentata. Corolla calycem 4-plo superans, tubo limbum aequante, galea truncata integra. : Fruticulus epiphytalis. Caules subtetragoni radicantes, novelli wie petioli et pedunculi pilis patentibus articulatis rubro-tinctis hirsuti. Folium in pare majus 6-7. 5 cm. longum 1. 5-2 cm. latum, alterum 18-30 mm. longue 1914] SMITH—PLANTS FROM CENTRAL AMERICA 425 8-13 mm. latum, nervis lateralibus utrinque 4-5, venis obsoletis, petiolis 1-2 mm. longis. Pedunculi singuli 4-6 cm. longi fuscescentes. Calycis obliqui viridis segmenta 1.5 cm. longa 7 mm. lata pilosa, dentibus utrinque 4 obtusis Sag spculati Corolla coccinea extus pilosa intus Sih peste 6-6. onga basi gibbosa, lobo antico triangulari-oblongo obtuso 16 m longo 7 mm. lato, lateralibus obtuse deltoideis cum galea ad 13 mm. scnnatiy margine superiore 8 mm. longis, galea propria 18 mm. longa 15 mm. lata. Stamina galeam usque ad 7 mm. superantia, antheris subquadratis 3 mm. longis. Disci glandula unica quadrata 1.5 mm. longa bifida. Ovarium ovoideum 4 mm. altum pilosum, stylo rubro cum staminibus supra medium puberulo, stigmate integro—Ad C. magnificam Klotzsch et Hanst. floribus accedens In silvis montanis ad Cobén, Depart. Alta gee Guatemala, alt. 1550 m., Jul. 912, A. von Tuerckheim, n. 2475. Columnea ($ EvucotumNnEA Hanst.) lutea Donn. Sm.—Folia leviter disparia subsessilia ovato- vel subrhomboideo-oblonga inaequilatera apice acuta basi obtusa vel retusa integra margine revoluta supra cano-strigillosa subtus nervis pilosa. Calycis seg- menta obovato-elliptica nervosa utrinque viridia et cano-villosa. Corolla lutea. Disci glandula minima bidentata. Fruticosa, caulibus ascendentibus approximatis pluribus teretibus, novellis et pedunculis patenter fusco-pilosis. Folia 2-3 cm. longa 10-12 mm. ee, nervis lateralibus utrinque 4-5, venis obsoletis, petiolis 1mm. longis. culi singuli rr mm. longi. Calycis segmenta 1 cm. longa 4 mm. lata. Corolla ex cl. repertore lutea extus arachnoidea intus glabra circiter 6 cm. longa incurva basi leviter gibbosa, lobo antico lanceolato-lineari 24 mm. longo 4 mm. lato, lateralibus cum galea usque ad ejus duas partes connatis margine superiore 6 longis, galea propria 12 mm. longa explanata 15 mm. lata fornicata emarginata genitalia superante. Stamina glabra, antheris 2 mm. longis 1.5 mm. latis. Disci glandula vix o.5 mm. longa. Ovarium cano-pilosum, stylo complanato bifariam puberulo, stigmatis lamellis ovatis 2 mm. longis. Bacca mm.-diametralis calyce accrescente bis superata, glandula 1.5 mm. longa.—Ad C. microcalycem Hanst. floris structura accedens colore abhorret. Cubilquitz, Depart. Alta Verapaz, Guatemala, alt. 350 m., Febr. 1901, H. von Tuerckheim, n. 7930 ex Pl. Guat. etc. quas ed. Donn. Sm aie Aegiphila (§ Cymosar Schau.; Subiruncatae Briq.) fasciculata Donn. Sm.—Folia longiuscule petiolata opposita lanceolato- oblonga utrinque acuminata supra bulboso-pilosa subtus ochraceo- fasciculatis. Calyx truncatus 4-mucronulatus. Stamina ananthera. 426 BOTANICAL GAZETTE [way Arbor, ramulis subtetragonis sicut petioli foliorum subtus nervi bracteae pedicelli calyces ochraceo-velutinis, internodiis superioribus 2-3 cm. longis Folia 15-22 cm. longa 5. 5-7.5 cm. lata tenuiter acuminata medio latissima, nervis subtus elevatis conspicuis, lateralibus utrinsecus 6-7, petiolis 2-3.5 cm. longis. Flores solum femini suppetentes in axillis subglomerati subsessiles 4-meri, — linearibus 6-12 mm. longis convolutis deciduis, pedicellis 1-2 mm. longi alyx turbinato-campanulatus 6-7 mm. longus minute mucronu- latus. Coralia infundibuliformis 9-10 mm. longa alba cum genitalibus glabra, lobis tubum intus furfuraceum aequantibus ovatis acutis. Stamina ad 2 mm, supra basin tubi inserta subulata r mm. longa. Stylus 12 mm. longus triente bifidus, ramis ee Drupa ignota.—A. tomentosae Cham. quoad inflo- rescentiam proxim n silvis prope eee. Depart. Alta Verapaz, Guatemala, alt. 1350 m., Dec. 1912, H. von Tuerckheim, n. 4013. Aegiphilae clavis specierum Centrali-Americanarum. I. Cymae axillares. Pac Sine SURG os oo ae ee se ek A. fasciculata Donn. Sm. B. Cymae pedunculatae. 1. Cymae densiflorae....... oy Oe Cee A. arborescens Vahl. 2. Cymae laxiflorae. O) PUppda ee A. —, Donn. Sm. b) Folia verticillata....... Be a ae hc se anomala Pittier. Il. Thyrsi axillares et terminales. A. Calyx truncatus. RPA ION es ey i aes A. martinicensis L. a Mam acute tetragons os eds. A. falcata Donn. Sm. B. Calyx lobatus. : 1. Corolla infundibuliformis...............:..A. brachiata peers Scutellaria (§ Vutcares Benth.; Coccineae Briq.) isocheila Donn. Sm.—Folia lanceolato-oblonga utrinque acuminata ve acuta sinuato-dentata discoloria praeter nervos subtus fusco- puberulos -glabra. Racemi foliis breviores densiflori, bracteis lanceolatis, inferioribus pedicello 2~3-plo longioribus, superiori- bus eo brevioribus. Corolla usque ad fauces graciliter tubulosa aequaliter bilabiata. Fruticulus erectus semimetralis parce ramosus, ramis subtetragonis cum petiolis racemis calyce fusco-puberulis. Folia 6-8 cm. longa 2-2.5 €™- - subtus pallida, nervis lateralibus utrinque 4-5, petiolis 8-11 mm. longis. Racemi terminales floribus ademptis 2-3 cm. longi 12-16-flori, bracteis 1914] SMITH—PLANTS FROM CENTRAL AMERICA 427 foliaceis, infimis 8 mm. longis, superioribus minutis, pedicellis 2-3 mm. longis, floribus oppositis secundis, yx 4 mm. longus, scutello 2 mm. longo. Corollae roseae pubescentis tubus 2.5 cm. longus, labia 3 mm. longa, lobi erecti integri, laterales cum postico breviter coaliti eum aequantes. Stamina majora 12 mm. longa alteris bis longiora, antheris canescentibus eciliatis, loculis omnibus polliniferis. Nuculae deficientes——S. Lindenianae Benth. ex char. proxima. In silvis humidis ad Cerro de Carizia, Prov. Heredia, Costa — alt. 1800 m., Sept. 1900, H. Pittier, n. 16128. BALTIMORE, Mp, THE OVARY AND EMBRYO OF CYRTANTHUS SANGUINEUS CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 186 MARGARET ELIZABETH FARRELL (WITH PLATE XXIV AND THREE TEXT FIGURES) Cyrtanthus sanguineus Hook. (Amaryllidaceaé) is one of the 37 species credited to the genus. It was first figured in the Botan- ical Magazine (1), and was copied by Pax (2) in his monograph of the family. The genus is restricted to South Africa. C. sanguineus and two other species were procured by Dr. C. J. CHAMBERLAIN from the Botanical Garden at Durban, a garden which, like most of those of the colonies, is supported by the nursery trade. The plants are not raised from seed in the garden, but are brought there after being dug up from places in which they grow naturally. The plants secured by Dr. CHAMBERLAIN have been growing in the greenhouses of the University of Chicago. The first blossoms appeared in the winter of 1912-1913.. They were hand-pollinated, and from the ovaries and embryos thus derived the present study was made. Cyrianthus sanguineus has a tunicated bulb about two inches in diameter. The leaves are thick and leathery, of a bright green color, and about a foot long. The epigynous flower is 3-4 inches in length, and of a rich coral color, almost crimson. The perianth tube is either suberect or decidedly curved, and the upper half of its throat is about one inch in diameter. The stamens are UNF seriate and slightly exserted; the filaments are incurved and the anthers are oblong. The ovary is 18 cm. long and 6 cm. in diameter. The ovules are campylotropous. In an ovary of about 12 ovules only 6 or 7 develop to maturity. Ovary The material was taken at different ages, killed in chromacetic fluid, and the sections stained in safranin and gentian. All the drawings were made with the help of an Abbé camera lucida. Botanical Gazette, vol. 57] [428 1914] FARRELL—CYRTANTHUS SANGUINEUS 429 The ovary is composed of three carpels. I found two different arrangements of their vascular bundles according to location. In the region of the lateral fusion of the carpels, there are three bundles grouped as one. All are collateral; the outer one is ectophloic, and the other two are so arranged that their xylem masses face each other (text fig. 1). The strands at the midrib of each carpel appear in three distinct groups; the outermost one consisting of a single collateral ectophloic bundle; the innermost one of two bundles with their xylem masses facing; and the intervening group composed of two double bundles, the degree of approximation of which differs at different levels in the carpel. One of the levels is shown in text fig. 2. This peculiarity of arrangement is probably due to the curving of the edge of the v carpels to form the closed ovary. A closer study led C V to an explanation of the different groups of bundles, and showed that each organ of the flower is supplied from these vascu- lar strands. Text fig. 3 is a diagram of the flower, the dotted line represent- ing the outline of the ovary. It can be seen that the abortion of the stigmas occurred opposite the region of the fusion of carpels. On tracing their bundles downward into the ovary, they are found to be derived from the primary groups in the carpel. Lower still, these bundles fuse with those of the flower stem. Noticing the frequent occurrence of stomata on the inner sur- face of the carpels, I was interested to know the relative number per unit of area in comparison with the outer surface. I found the relation to be as 8:5 in favor of the inner side. This is con- trary to what we should expect, for in the foliage leaves of Cyr- tanthus the stomata are more numerous on the abaxial surface. Fic. 1.—Showing the vascular arrangement at the fusion of the carpels. 430 BOTANICAL GAZETTE [MAY Some of the ovules which were killed in the early stages were examined and found to contain an embryo sac of the lily type. The Fic. 2.—The vascular arrangement at the midrib of the carpel a ee 7 ~s 2 ee aaa feo -_ ww ™ - 3 Fic. 3.—Diagram of a flower of Cyrtanthus against the ovary (dotted line), show- ing the relation between the vascular conditions and the parts of the flower; p, petals $, sepals; c, carpels. antipodals, synergids, and egg showed no departures from this type in the mature stage of the gametophyte; the development up to this stage was not seen. 1914] FARRELL—CYRTANTHUS SANGUINEUS 431 Embryo The literature of the embryos of monocotyledons is extensive but not satisfactory. The ‘sheath’ was recognized, of course, early in the history of the study, and was presumed to be a single cotyledon, giving the name to the whole class. Besides the presence of the single cotyledon, early investigators were so impressed with the large amount of endosperm or “albumen,” as they called it, occurring outside the embryos in such seeds, that they also called them ‘‘albuminous.” As to the origin and nature of the cotyle- donary sheath, various opinions are expressed, which fact perhaps demonstrates that there are various modes of origin. The earliest writers, HANSTEIN (3) and FAmiIntzin (4), described the embryo of Alisma Plantago, in which the cotyledon is terminal in origin. HEGELMAIER (5) describes it in some cases as arising from a cell near the tip, and being pushed into the terminal position by later development. SHAFFNER (6) says that in Sagittaria the cotyledon arises from the terminal cell of the proembryo. CAMPBELL (7) finds the same condition in Naias; the same author in his study of Lilaea (8) says that the sheath is not at first an enveloping organ, but that it becomes such by the lateral growth of its margins; and the same facts are repeated for the Araceae (9). WITTMACK (10) in his monograph on the Bromeliaceae has a drawing of a longi- tudinal section of the embryo of Guzmannia tricolor, taken through the center in such a way as to show the elongated side of the sheath on one side and the shorter side on the other. He calls the long side the “‘scutellum” and the short side the “cotyledon.” There is nothing in his figure to show that scutellum and cotyledon are not one and the same structure, and yet it would seem that so reliable an investigator must have had some reason for applying the two terms in this way. BILLINGs (11) says that the cotyledon is terminal in origin, that the middle segment of the three-celled proembryo gives rise to all the other organs, and that before the stem tip is differentiated, the cells surrounding the area where it is to arise grow up into a ridge of tissue, which in the mature embryo incloses the growing point completely. Here the author seems to imply (1) that the sheath does not completely inclose the growing point in its inception, and (2) that the sheath is not the cotyledon, in the latter respect agreeing-with W1TTMACK. 432 BOTANICAL GAZETTE [MAY A new impulse was given to the study of embryology when COULTER and CHAMBERLAIN began the revision of their Mor- phology of gymnosperms (15). Especially was the impulse felt among the cycads. Cycads were collected from the oriental and - occidental tropics, and all phases of their life history investigated. The dicotyledonous nature of the cycadean embryo was demon- strated for all of them, even that of Ceratozamia (12, 13), which had been reported as having a single cotyledon. But while these embryos were shown to be normally dicotyledonous, exceptions to dicotyledony were seen to be by no means rare. The case of Ceratozamia was proved to be the result of abortion; but in Micro- cycas a condition was found in which the cotyledons were fused to such an extent that the author of the investigation referred to the fused structure as a “sheath,” and expressed the suspicion that monocotyledony, even in angiosperms, might have arisen in both these ways: suppression, as in Ceratozamia, and fusion, as in Micro- cycas. COULTER and CHAMBERLAIN, in their chapter on evolu- tionary tendencies (15), seem to give credence to this suspicion by requesting Sister HELEN ANGELA to illustrate her views on the subject of the primitiveness of polycotyledony and the tendency to reduce the number of cotyledons. From the material at my disposal, I was able to procure embryos in two different stages of development. The younger one was found to consist of an enveloping sheath, still meristematic and with four distinct lobes at its apex. Each lobe has its own vascular strand, four separate strands arising from the four poles of the root. The lobes are approximately equal in size at this stage, but not absolutely so, as can be seen from fig. 2. At the base of the sheath is the region from which the stem tip will arise later; at this stage it is not meristematic. Figs. 1 and 2 of the plate are sketches of the exterior and interior of the embryo at this stage, and fig. 3 is a cross-section which illustrates the irregular growth in thickness of the sheath, the region which bears the vascular strands resisting the pressure from without and giving the ap pearance of lobes and a four-sided aperture. : The second embryo studied (fig. 4) is older than the one just described. The sheath now consists of two regions, a lower portion 1914] FARRELL—CYRTANTHUS SANGUINEUS 433 which still envelops the growing point, and a long upper projection which has resulted from the greater growth in length of one side of the sheath. The tip of the shorter, aborted side of the sheath is seen at a in figs. 4, 5, and 15. The vacant space in this older embryo, unlike that of the younger, which was four-lobed, is now reduced to the narrow slit represented by s in figs. 13 and 14. The vascular conditions are indicated in fig. 5. In the lower region of the sheath (the completely enveloping region below the abortion) each side has two vascular strands, making four in all (figs. 8-13), which arise independently from the cotyledonary node and enter the two differentiated sides of the sheath, just as happens in many dicotyledonous seedlings (figs. 5 and 7). Near the tip of the lower or aborted side of the sheath, the vascular strands from that side abruptly enter the region of the extended side, and fuse with the vascular strands of that organ. At this stage of development, the growing point has differ- entiated the first and second leaves, the first arising on the side corresponding to the aborted side of the sheath, and the second one about opposite the first. All are closely pressed upon by the grow- ing sides of the sheath. These arrangements are shown in figs. 5 and 10. The root cylinder is tetrarch (fig. 6). Discussion As was remarked before, the amount of endosperm in the seeds of Cyrtanthus is very great in proportion to the size of the embryo. This makes it difficult for the embryo to develop its organs to their full extent. I have noted how the originally large space within the sides of the sheath is reduced, little by little, as growth progresses, to a very small space (s, figs. 3, 13, and 14). Following out this process in thought, it is not difficult to imagine how the early condition indicated in fig. 3 might easily be changed into that of figs. 4 and 5 merely by the mechanical pressure of the large endo- sperm. In other words, the sheath of monocotyledons is probably a fusion of two or more cotyledons; the probability amounting almost to a certainty when we remember that the very same con- dition here described in a monocotyledon has been discovered in the dicotyledonous embryo of Microcycas, a complete fusion of the 434 BOTANICAL GAZETTE [MAY two cotyledons. Looking at fig. 1 of pl. V in the Microcycas paper (14), and comparing it with my fig. 13, one would be puzzled to say which is the dicotyledon and which the monocotyledon. The same difficulty would arise by comparing my fig. 10 with fig. 13 of pl. VI of the Microcycas paper. Sister HELEN ANGELA was 80 impressed with the complete fusion of the two cotyledons that she called the fused structure a sheath. Furthermore, a consideration of the vascular connections, the four root poles with their extensions finding full outlet in the sheath, shows that this sheath represents the whole cotyledonary apparatus, which, historically, finds its expression in many cotyledons in Pinus, in two in the normal cycads and dicotyledonous angio- sperms, and in the sheath of monocotyledons. This condition seems to me almost the last proof necessary to demonstrate the origin of monocotyledons from dicotyledons. Summary 1. The embryo sac of Cyrtanthus seems to follow the regular Lilium type. The endosperm is very extensive. 2. Stomata are more numerous on the inner than on the outer surface of the carpel. 3. There are three separate bundles at the midrib of each carpel and two at the fusion of the carpels. This arrangement is related to the various parts of the flower. 4. The youngest observed stages of the embryo have the stem tip enveloped by a sheath with four lobes at its top. 5. In an older embryo the sheath is differentiated into a longer and a shorter side, the appearance and vascular anatomy of which give the distinct impression of two cotyledons. 6. Any pressure or fusion is referred to the extraordinary amount of endosperm. 7. The investigation is considered a last proof of the theory of monocotyledony from dicotyledony. The author wishes to express her grateful acknowledgment to Dr. Cuartes J. CHAmBeRtatn for material, to Dr. Joun M- 1914] FARRELL—CYRTANTHUS SANGUINEUS 435 CouLTEeR and Dr. W. J. G. Lanp for kind assistance during the early part of the investigation, and to Sister HELEN ANGELA under whose direction it was completed. THE COLLEGE oF SAInt ELIZABETH Convent Station, N.J. LITERATURE CITED - Botanical Magazine, pl. 5218. Pax, F., Monograph on Amaryllidaceae in ENGLER and PRANTL’s Natiir- lichen Pflanzenfamilien. 1889. - Hanstern, J., Entwickelungsgeschichte der Keime der Monocotyledonen und Dicotyledonen. Bot. Abhandl. Bonn. p. 112. 1870. - Famintzin, A., Embryologische Studien. Mém. Acad. Imp. Sci. St. Pétersbourg 26:10. 1879. EGELMAIER, F., Zur Entwickelungsgeschichte monocotyledoner Keime nebst Bemerkungen iiber die Bildung der Samendeckel. Bot. Zeit. 32: 631. 1874. 6. SHAFFNER, J. H., Contribution to the life history of Sagittaria variabilis, w wow ae “ 97- 7. CAMPBELL, D. H., A oe study of Naias and Zannichellia. Proc. Calif. Acad. Sei: bai Me & 1897. , The development of ihe bees and embryo in Lilaea subulata HBK. Ann. Botany 12:1-28. , Studies on the Araceae. yee Botany 14:1-25. Io. Wirrmack K, L., Monograph on Bromeliaceae in ncten ee PRANTL’S Natiirlichen Panaeetaciiica. 1889 11. Biriincs, F. H., A study of T: landsio usneoides. Bot. GAZ. 38:99-121. 1904. 12. ANGELA, Sister HELEN, The embryo of Ceratozamia: a physiological study. Bot. Gaz. 45:412. 1 , The seedling of Foratesamis. Bor. GAz. 46:205. 1908. , Vascular anatomy of the seedling of Microcycas calocoma. Bor. Gaz. 47: 139-147. 1909 15. Courter, J. M., and Caanceanxane, C. J., Morphology of gymnosperms. Chicago. 1910. a EXPLANATION OF PLATE XXIV The drawings were made with the aid of an Abbé camera lucida, the mag- nification used being 120 diameters. In every case, a indicates the tip of the aborted or short side of the sheath, c the longer side, and s the space within the sheath. IG. 1.—Exterior view of a young embryo before the differentiation of the two portions of the sheath. 436 BOTANICAL GAZETTE [MAY Fic. 2. —Longitudinal section through the center of the embryo shown in fig. I. Fic. 3.—Cross-section of a young sheath above the region of the growing point of the stem. Fic. 4.—Exterior view of an older embryo, showing differentiation of both se of the sheath. IG. 5.—Longitudinal section (partly reconstructed and diagrammatic), showin the first leaf, the growing point, and the behavior of the vascular S. Fic. 6.—Cross-section through the root cylinder of the older embryo. 1G. 7.—Cross-section of the cotyledonary node, showing the independent origin of the four bundles. Fic. 8.—Cross-section just above the cotyledonary plate; the four bundles have assumed the vertical position IG. 9.—Cross-section above that uiceiecud in fig. 8, showing the stem cylinder. Fic. 10.—Section pense the preceding, showing the first leaf and the growing point. Fic. 11.—Cross-section above the tip of the second leaf. Fic. 12.—Cross-section just above that shown in fig. 11; it shows the tip of < oe leaf. . 13-—Cross-section above the tip of the first leaf; shows the space or slit rei the two sides of the sheath. Fic. 14.—A section showing the fusion of the Bes bandigs to make two; it was made immediately above that shown in fig. Fic. 15.—A section near the tip of the sac yon of the sheath, giving the appearance of two cotyledons lying side by side. Fic. 16.—A cross-section in the upper part of the sheath. BOTANICAL GAZETTE, LVII PLATE XXIV Margaret E- Farrett deb. FARRELL on CYRTANTHUS CURRENT LITERATURE BOOK REVIEWS Textile fibers A book by Srirmt on the chemical technology of textile fibers deals with every phase of the derivation and handling of the fibers: source, method of obtaining, physical and chemical character, washing and bleaching of the raw fiber, preparation for stamping and dyeing, and stamping and dyeing them- “ee The work covers plant fibers (cotton and various bast fibers, such as ax, hemp, jute, and manila), animal fibers (wool, hair, and nite fibers (asbestos), and artificially produced fibers from mineral raw materials (glass and mineral fiber) and from plant raw materials (India ine fiber and artificial silk). The work on plant fibers reminds the botanist of the detail with which these technical workers have studied the histology, chemistry, and physics of cotton, bast, etc. In the case of cotton, one finds a summary of our knowledge of the histology and microchemistry of the fiber. The chemical composition of the fiber is given, including the substances involved as impurities, with methods of removal. The chemistry of cellulose is dealt with briefly, with various theories as to its molecular weight and structural formula. The behavior of cellulose toward many reagents in various con- centrations (acids, bases, salts, oxidizing and hydrolizing agents, and various solvents) is clearly summarized. The changes involved in such processes as bleaching, mercerization, and formation of artificial silk are discussed, along with the theories offered in explanation. The author recognizes many of the problems with cellulose as belonging to the field of colloidal chemistry. The histology and chemistry of bast fibers receive like consideration. The work reminds one that the knowledge useful to the technical worker is often the same as that which is of significance to the “pure” scientist.—WILLIAM CROCKER. MINOR NOTICES The Journal of Ecology.—It is rare that a new journal starts off so well as does the Journal of Ecology,? the first volume of which is now completed. In 1904 a great advance was made in ecological study in the British Isles by the Stir, Kari ae Technologie der Gespinnstfasern. xvi+410. Berlin: Gebriider orstranses: 19 ? The Journal of meds edited for the British Ecological Society by FRANK Cavers, Cambridge University Press (American agent: The University of Chicago Press). Volume I. 1913. Price per annum, $3.75. 437 438 BOTANICAL GAZETTE [MAY organization of the Central Committee for the Survey and Study of British Vegetation, more popularly known as the British Vegetation Committee. This organization secured the effective cooperation of British ecologists, and among other things has to its credit the organization of the International Phyto- geographic Excursion of 1911 and the publication of Types of British vege- tation. In 1912 there was formally organized the British Ecological Society, which has become the successor of the British Vegetation Committee. One of the chief tasks of this new society is the publication of a journal. ‘The first thought was to have this new journal be little more than an organ of the British ecologists. But a broader view prevailed, and we now have an inter- national journal devoted to ecology, the first of its kind; from the first, number the quality of the journal has been such as to give it cant with the foremost botanical periodicals. The scope of the new ecological journal is such as to make an effective appeal to ecologists of other lands quite as much as to those of the British Isles. To facilitate use by both general and local readers, articles and reviews of general nature are kept distinct from those of more local significance. To the writer the “high-water mark” of the new journal seems to be reached by its reviews. It is doubtful if the reviews in any other botanical journal equal in efficiency those of the new Journal of Ecology. They. are models as to thoroughness and accuracy, in many cases making it really unnecessary to consult the original papers except to secure details. It is unusual and highly illuminating to have published in many of the reviews the more significant Sores of the original papers. The only adverse criticism that the writer make is that the reviews generally are unsigned. It goes without saying Me the new journal is absolutely necessary for the working ecologist. The British ecologists may well congratulate themselves upon their accomplish- ments during the last decade. In 1904 their work was scattered and mostly of local significance; today they are oy cepecercend the leaders in cooperative ecological activity——H. C. Cowie American Journal of Botany.—The first number of this new journal has ared, and needs no explanation to American botanists. It is the official pablicalion of the Botanical Society of America, and is published by the the increase of means of publication has not kept pace with production. “ The result has been that our established botanical journals in America are ovet- stocked with manuscripts waiting their turn, our colleges and universities are making outlets for their own production, and foreign journals have their courtesy and capacity taxed by the offers of American contributors. All three of the conditions just named are undesirable: an author does not like to wait a year or more for the publication of his paper, the multiplication of small periodicals by colleges and universities is a vexation to research, and it is neither 1914] CURRENT LITERATURE 439 just to ourselves nor kind to our colleagues of other lands to ask them to give large printing space to our contributions.”’ It is evident that the new journal will relieve this pressure somewhat, which the established journals have felt keenly. This initial number contains the following papers: “The development of Agaricus arvensis and A. comtulus,” by Gro. F. ATKINSON; “Studies of tera- tological phenomena in their relation to evolution and the problems of heredity. I,” by Orntanp E. Wutre; ‘Nuclear behavior in the promycelia of Caeoma nitens Burrill and Puccinia Peckiana Howe,’’ by L. O. KunKEL; and “An axial abscission of Impatiens nea as the result of traumatic stimuli,” by R. A. GortNER and J. A. Ha —J.M. C. Illinois Academy of Science.—The volume of Transactions of the Illinois Academy of Science for 1913 contains the following botanical papers: “Anno- tated list of the algae of eastern Illinois,” by E. N. TRANSEAU; ‘‘Reproduction by layering in the black spruce,” by Geo. D. FULLER; “Evaporation and soil moisture on the prairies of Illinois,” by E. M. Harvey; and “The stratification of atmospheric humidity i re the forest;’”’ by Gro. D. FULLER, J. R. LOCKE, and Wave McNutr.—J. M. NOTES FOR STUDENTS Paleobotanical notes.—ARBER? has done a most useful service in revising the seed-impressions of the British Coal Measures, and putting them into more definite categories. The most recent list, that of KmpsTon in 1894, included 5 genera with 19 species. ARBER’S revision contains 14 genera with 37 species. These detached seed-impressions belong to both Cycadofilicales and Cor- daitales, whose seeds cannot be distinguished. Of the 14 genera recognized 9 are new (Platyspermum, Cornucarpus, Samarospermum, Microspermum, M. egalospermum, Radios ermum, N eurospermum, Schizospermum, Pterosper- is figur Mrs. ArBErR‘ has examined sections of a new specimen of Trigonocarpus, Showing that the sclerenchyma of the micropylar beak is preserved as far as its extreme apex, and also that the nucellus was free from the integument almost to the base of the seed. KNow.ton’. has described a collection of Jurassic plants from Alaska, obtained between latitudes 68° and 69°. SEWARD’s report on a collection of 3 ARBER, E, A. NEWELL, A revision of the Ctib opine Rea of the British Coal Measures. Ann. Botany 28:81-108. figs. 8. pls. 6-8. 1914 * ARBER, AGNES, A note on Trigonocarpus. Ann. beias 28:195, 196. fig. I. I9T4. ’ Knowrron, F. H., The Jurassic flora of Cape Lisburne, Alaska. U.S. Geol. Survey. Professional paper 85-D. pp. 39-55. pls. 5-8. 1914. 440 ‘BOTANICAL GAZETTE [MAY Jurassic plants from Siberia (Amurland) makes a comparison of Alaskan and Siberian Jurassic floras possible. KNowLton concludes that the striking simi- larity between the Jurassic floras of northwestern North America and eastern Siberia shows that the land connection between these regions during the Jurassic must have been practically continuous. The Alaskan list recognizes 12 genera and 17 species, the solitary species of Equisetum being described as new. The dominance of cycadophytes is obvious, so far as it can be inferred from so small a number of species, the list being as follows: pteridophytes 5; cycadophytes 11; and Ginkgo represented by a single species. SALISBURY® has described in detail a new species of Trigonocarpus obtained from the Lower Coal Measures at Shore Littleborough, England. In addition to the well marked features of the sclerotesta and sarcotesta, the nucellus is almost completely free from the integument, and has a well developed and thick walled epidermal layer, three longitudinal flanges corresponding with the commissures, and numerous secretory sacs in the ground tissue. The conclu- sion is reached that this species is more primitive than its congeners, and that the testa arose from the lateral fusion of a whorl of six originally free members. A discussion of the resemblances and differences between the Trigonocarpeae and the Lagenostomales reaches the conclusion that they are to be explained by intercalated growth, followed by subsequent fusion of the nucellus and integument. Dr. Stopes? has published a very interesting lecture upon the past and future of paleobotany, delivered at University College, London. The thesis is that paleobotany is now an independent — contributing to both botany and it and with its own important HOMAS and Bancrort® have made a "detailed comparative study of the cuticle of recent and fossil cycads, including also mention of other gymnosperms, especially with reference to the form and structure of the stomata. The see conclusion is that the characters presented by the stomata and epider- mal cells o gymnosperms are important as indicating to some extent their relatio eat Among the cycadophytes there are some characters which have undergone little modification from the Jurassic to the present time, and the authors conclude that stomatal structure is the expression of ancestral charac- ters rather than of purely local and temporary conditions of environment.— Ber Be 36 ® SALIsBurY, E. J., On the structure and ti f Trigonocar pus shorensis, sp. nov. A new seed from the Paleozoic rocks. Ann. Botany 28:39-80. figs. 8. bls. 4, 5. 1914 7 Stopes, Marte C., Paleobotany; its past and its future. Knowledge 37° 15-24. I914 , ae. H. Hamsuaw, and Bancrort, NELLIE, On the cuticles of some recent and fossil cycadean fronds. Trans. Linn. Soc. London II. Bot. 8:155-204- figs. 32 pls. 17-20. 1913. 1914] CURRENT LITERATURE 441 Hydrogen and alcoholic fermentation.—Through a study of the reduction of methylene blue, in the presence of yeast, Lvorr? has found further Beast that reductase plays an essential réle in alcoholic astemaggws blue is rapidly decolorized when placed in a yeast culture. This fee is brought about through the absorption of two atoms ie nascent hydrogen (molecular H is not effective) at the double bond of the color group. Reduc- tase activates the hydrogen. He finds the output of alcohol and CO, greatly lowered while the methylene blue is being reduced. Therefore the hydrogen, activated by the reductase, probably goes directly to the methylene blue mole- cule, thereby arresting the further normal steps of the fermentation process. Quantitative determinations of the CO, and alcohol produced and the hydrogen absorbed (by the methylene blue) showed that one gram-molecule of methylene blue takes from the fermentation medium one gram-molecule of hydrogen and “inactivates”? one gram-molecule of hexose, thus preventing the splitting into alcohol and CO,. Unfortunately, a study of this “inactivated” carbohydrate * has not been made. in, yeast when mixed with water only still has the capacity for reducing ei iece blue. CO, is given off at the same time in amount directly related to the methylene blue reduced; for example, one gram-molecule methylene lue, under conditions favoring self-fermentation, takes one gram-molecule of hydrogen from the medium, liberating one gram-molecule of CO,. The source of this CO, is yet unexplained. However, the author suggests the possibility that it comes from the fermentation of amino acids in the yeast, a suggestion in agreement with the work of Exrticu, and Snorage with that of Bacu, where from amino acids in the presence of alloxan, NH;, CO., and 2H are eliminated (the a passing to the alloxan), leaving an aldehyde in the medium. >-E. M. Harve Cytology and embryology of Smilacina.—Smilacina was studied some time ago by Lawson,” who reported that synapsis is due not to a marked con- traction of the nuclear contents, but to a sudden enlargement of the nuclear cavity, which gives the appearance of a contraction. McALLisTERr™ claims that synapsis is due to contraction and not to any considerable enlargement of the nuclear cavity. It would seem as if this should be settled by measurement rather than by discussion, but since both men studied Smilacina and both made measurements, an extensive series of measurements of various forms would seem to be in order. *Lvorr, Gercrus, Hefegirung und Wasserstoff. Zeitschr. Garungsphysiol. 3: 289-320. 1914 0 LAWSON, - A., The phase of the nucleus known as synapsis. Trans. Roy. Soc. Edinburgh 47: 591-604. pis. 2. 1911. Rev. in Bor. Gaz. §1:313- 1911. * McAuuster, F., On the cytology and embryology of Smilacina racemosa. Trans. Wis. Acad. Sci. 17:599-660. pls. 56-58. 1913. 442 BOTANICAL GAZETTE [MAY During synapsis McAtuister finds that there is a lateral pairing and fusion of spirems, the fusion being complete at the time of the recovery from ynapsis. After this recovery there is a second contraction stage. The double heterotypic chromosomes are formed, not by the approximation of the limbs of loops, but by a transverse segmentation of a longitudinally split spirem, the line of the split probably representing the line of approximation of the two parental spirems seen at synapsis e heterotypic and lintestynle mitoses in the megaspore mother cell result in the formation of four megaspores, separated by plasma membranes The membrane formed at the heterotypic mitosis persists, while those formed at the homotypic mitosis quickly break down. From the inner binucleate cell, thus formed, an 8-nucleate embryo sac is developed. Consequently, two mega- spores are concerned in the development of the embryo sac. Adventitious embryos develop from nucellar cells in the micropylar region, and one or more of them may become mature. The presence of pollen tubes indicates that embryos may also result fot fertilization CHARLES J. HAMBERLAIN. Marine algae.—BorcEsEN” has published an account of the marine Chlorophyceae of the Danish West Indies, based upon collections made in 1892, 1895, and 1905. The list contains 34 genera including 86 species, 4 new species being described in Cladophora (2), Avrainvillea, and Pringsheimia. The full field notes and the numerous illustrations make the account an exceedingly satisfactory one. BorGENSEN® has also given an account of the species of Sargassum col- lected during his three visits to the Danish West Indies, partly along the coasts of the islands, and partly in the Sargasso Sea. The shore collections include 4 species, while the pelagic collections are all referred to two species. The discussion of the “biology, affinities, and origin of the gulfweed”’ is especially interesting. The conclusions reached are that the gulfweed of the Sargasso Sea consists of two species, S. natans (most common) and S. Hystrix, var. fluitans; that they are true pelagic algae, living perennially on the open sea; and that most probably they have descended from shore forms of the West Indies and the neighboring American coast. The author says “it is of great interest that we have an instance of floating, pelagic species of such a high alga type as Sargassum; because, as is well known, the higher types of algae are as a rule attached, and if detached they perish sooner or later.” —J. M. C ™ BORGENSEN, F., The marine algae of the Danish West Indies. Part I. Chloro- phyceae. Dansk Botanisk Arkiv 1: ‘no. 4. pp. 158. figs. 126 and chart. 1913. Copen- hagen: H. Hagerup. Kr 4. 3 , The species of Sargasswm found along the coasts of the Danish West ks upon the floating forms of the Sargasso Sea. Mindeskrift for Japetus Steenstrup. pp. 20. figs. 8. 1914. 1914] CURRENT LITERATURE 443 Reproduction in Scenedesmus.—Although Scenedesmus is a very familiar alga, the details of its reproduction had not been investigated, doubtless because the cells areso small. Smrru™ has studied the cell structure and reproduction in all of the three species. The cells are strictly uninucleate, contain a single pyrenoid, and have a cell wall consisting of two layers. When 4-celled colonies are formed, the steps are as follows: The first nuclear division is followed by a transverse cleavage of the cytoplasm, and nuclear division in the two resulting protoplasts is followed by cleavage furrows at right angles to the first furrow. de novo within each of the four cells, and cell walls appear. The young colony escapes through a longitudinal ‘rupture in the wall of the mother cell and assumes the characteristic arrangement by unrolling. In the formation of 8-celled colonies, there are three nuclear divisions, the second and third being followed by cytoplasmic cleavages. The material for the study was grown in pure cultures. Sections were cut from 3-5 in thickness and stained in Flemming’s safranin-gentian violet-orange combination.—C. J. CHAMBERLAIN. The embryo of Gyrostachys.—The origin and development of the embryo sac of Gyrostachys, more commonly known as Spiranthes, is described for two species, S. gracilis and S. cernua, by Miss PAce,'s whose previous work allows her to speak with authority upon this subject. The embryo sac is very irregu- lar in its development, sometimes arising from 4 megaspores, sometimes from 2, and sometimes from only one. At the fertilization stage the embryo sac may contain 4, 5, 6, or 8 nuclei, the 6-nucleate condition, resulting from a lack of one mitosis in the chalazal end of the sac, being the most frequent. The diploid number of chromosomes in S. gracilis is 30, and in S. cernua 60; con- sequently, the relation, in this respect, is similar to that between Oenothera Lamarckiana and O. gigas, and S. cernua might be called a tetraploid form. As is well known, S. cernua is a larger and more vigorous species, and the gigantism is evident also in the size of the ovary, the ovules, and the size of the cells. Miss PAcE suggests that the subject might be worth investigating experi- mentally.—CHarLes J. CHAMBERLAIN. Westphalian Calamariaceae.—A revision of the pea Calimsitincsus undertaken in conjunction with Kipston, impressed upon JONGMANS the frag- mentary condition of our knowledge of the Calamariceae of the Rheinish- Westphalian coal fields, and also the inadequacy of the descriptions and figures. Accordingly, with the cooperation of KukuK,™ he examined and described MITH, GILBERT M., The cell structure and pea formation in Scenedesmus. Acchis fiir Patina! 32:278-207. pls. 16, 17. 19 *s Pace, Luba, Two species of Gyrostachys. Pa University Bull. 17:1-16. pl. I. 1914. 6 Joncmans, W. J., and Kuxux, P., Die Calamariaceen des Rheinisch- Westfalischen Kohlenbeckens. Mededeelingen van’s Rikjs Herbarium. Leiden. no. 20. Text 8vo. pp. 89. Atlas 4to. pls. 22. 1913. 444 BOTANICAL GAZETTE [MAY specimens from the following collections: K. Pr. Geol. re Berlin; Stidt. Museum, Chemnitz; Naturw. Museum, Dortm SR Ged: Reichsanstalt, Wien; Murkisches Museum, Witten; ican Oanadri ck; s’Rijks Herbarium, Leiden; Geol. Institut der Universitat, Gottingen; Geol. Institut der Bergakademie, Clausthal; and Geol. Institut der Universitat, Miinster i.W. The work is strictly taxonomic. The descriptions and synonomy are very complete, and the magnificent plates enable one to study the subject almost as well as if he had the actual specimens in his hands.—CHARLES J. CHAMBER- LAIN. Anatomy of petioles of Cycads.—Lr Goc” has studied the debated xylem situation in the foliar bundles of the cycads. As is well known, both centrip- etal and centrifugal xylem occur, a situation which has been variously inter- preted, but in general the bundle has been spoken of as mesarch. LE Goc has found that at the very base of the petioles in cycads the xylem is entirely cen- trifugal, and that later the bundles assume different forms, becoming con- centric, collateral, or a combination of these two arrangements. He regards the centrifugal xylem at the base as a secondary growth, and the centripetal xylem which appears later as a primary structure, laid down early, but only two one remain ames and therefore he would suggest that the bundle is more properly called “‘pseudo-mesarch.”’—J. M. C. The origin of the “eye spot.”—From a study of the literature, without any apparent study of the structures themselves, ROTHERT™ comes to the conclu- sion that the “eye spot” of flagellates and algae is derived from a plastid. The evidence seemed clear already, so far as the Pupuerene are concerned, and GUIGNARD, as long ago as 1880, claimed that the “eye spot” seen in the sperms of Fucus arose from a colorless plastid. RoTHERT overlooks entirely the various papers by YAMANOUCHI from 1 to 1913, partecey the paper on Cutleria,® in which the origin and development of the “eye spot’’-are described in detail—C. J. CHAMBERLAIN. 7 LE Goc, M. f., Berea on the centripetal and centrifugal xylems in the petioles of — Ann. Botany 28:183-193. pl. 11. fig. I. 1914. RoTHErT, WiaptsLaw, Der “Augenfleck”’ der one und Flagellaten ein Chromoplast. “te Deutsch. Bot. Gesells. 32: 91-96. 1914 ucHI, SHicEo, The life history of Culleria. Bort. GAZ. 54: 441-502. jigs. ns pls. 2045 1912. Volume LVII Number 6 THE BoTANICAL GAZETTE Editor: JOHN M. COULTER JUNE r10%4 Winter as a Factor in the Xerophily of Certain Evergreen Ericads Frank Caleb Gates — The Morphology of Araucaria brasiliensis. I L. Lancelot Burlingame The Origin of Monocotyledony John M. Coulter and W. J. G. Land A Method of Controlling the Temperature of the Paraffin Block and Microtome Knife W. J. G. Land Briefer Article Successful Artificial Cul € Clit yb iliud d Armillaria V. H. Young The “quae of Bare Ground in Some Mountain Grasslands Francis Ramaley The Oxidases of Acid Tissues G. B. Reed The Type Species of Danthonia Aven Nelson and J. Francis Macbride Maturation in Vicia Lester W. Sharp Current Literature fe The University of Chicago Press CHICAGO, ILLINOIS, U.S.A. Agents THE CAMBRIDGE UNIVERSITY PRESS, London and Edinburgh Pingo & ripe London ‘ial ciara oc "Dekel : The Botanical Gazette BA Monthly Journal Embracing all Departments of Botanical Science Edited by Jonn M. CouLter, with the snl th of vei members of the botanical staff of the University of Chic Issued June 19, soul Vol. LVII CONTENTS FOR JUNE 1914 No. 6 WINTER AS A FACTOR IN THE Peer ee se CERTAIN BY RROREED. aeons (WITH TWELVE FIGURES). Frank Caleb Gate. THE ee pena iee. a ARAUCARIA ee II. THE OVULATE CONE AND FEMALE GAMETOP id Sad (WITH PLATES XXV-XXVII AND TWO .FIGURES) L. Lancelot Burlingame - Po a Meee Oe! ae - - 490 THE ORIGIN OF MONOCOTYLEDONY. Conrrisutions From THE HULL BOTANICAL LABORATORY ype aes PLATES XXVIII AND XXIX AND TWO get at a = atc nd W.J.G. La @ A METHOD OF CONTROLLING THE TEMPERATURE OF THE PARAFFIN BLOCK AND MICROTOM E. CONTRIBUTIONS FROM THE HvLL BOTANICAL pers WITH TWO ots W.J.G. Land me ee Aina = 520 BRIEFPER ARTICLES Su ree ARTIFICIAL CULTURES OF a TILLUDENS AND ARMILLARIA ee Al pose sa Wie Vidi; 524 THE eusont OF BaRE GROUND IN SOME Mbeaceause Gaasstanns. pe Romaley:- > -, §26 THe OxmpAsEs oF Actp B. - . §28 Tue Type SPECIES oF DaANTHONIA. Aven Nelson and F. Francis Macbride - - - 530 MATURATION IN Vicia. Lester W. Sharp - - * pies H rg dprid ad LITERATURE. math pee ey mapa OF mane BIOLOGY AND CAPILLARY ANALYSIS OF ENZYMES. FIELD MANUAL 0: ioe wevias: On cays be Re eet ey Mpa I RMR NOTES FOR STUDENTS BOR a ee ats tae ol eae a ok gS. of Sis ies is 75 cents. Orders for service of less than a half-year will be sat al at ae fs copy rate eae is prepai _ by publishers on all m the United States, Mexico, Cuba, Port ; Canal Zone, let of P Hawaiian Islands, Philippine Islands, Guam, Parsee iiiende SI Shang ai. {Pos is char, tr ollows: For Canada, 35 cents on annual fect (total $7.35), on pre hs opies, 3 pone (total 78 cents); for all other countries in the Pas on, 84 cents on annual subscriptions (total $7.84), on single copies, 11 cents (total $6 cents). {Re tances should be made pa he University of Chicago’ Press, oul in Chicago or New York exchange, postal or express money order. 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The Santicheee expect ‘to supply chim ye sa free only when they have been lost in tra Business correspondence should be addressed to The University of Chicago Press, Chicago, IIl. tions for the editor and pare Sd should be addressed to the Editor of THe BOTANICAL ted to write stientiGic d proper names with particular care, to use the metric system of or ap pba Souda. and in citations to Car, the form shown in the pages of the Botanical : n excess of thirty-two. printed pages a t ace — d unless the author is bet de to acd the _. cost of the additional pages, in w of pages in the eased. : furnished without cost to author only et suitable originals are supplied copy number, 1907, will be sent on applica’ sigan It is atyhabie to VOLUME LVII NUMBER 6 Tne BOTANICAL GAZETTE JUNE sora WINTER AS A FACTOR IN THE XEROPHILY OF CERTAIN EVERGREEN ERICADS! FRANK CALEB GATES (WITH TWELVE FIGURES) Of late years considerable attention has been drawn toward the apparently anomalous condition of several plants with obvious xerophytic modifications living in bogs with an apparently unlimited water supply. Many explanations of this apparent anomaly have been attempted. It was with a desire to obtain further knowledge upon the question that the author entered upon this piece of research work in the Botanical Department of the University of Michigan in the fall of 1910. The work was carried on under the direction and supervision of Professor F. C. Newcomspe. To him I am greatly indebted both for the opportunity to work and for his stimulating criticism throughout the work. To Dr. H. A. Greason and to Dr. J. B. PotLock, both of the University of Michigan, I am also indebted for helpful conferences during the course of the work. To Mr. W. B. McDoveatt, of the University of Michigan, I am further indebted for the examination of material for the presence of myco- thiza. The nomenclature is that of the seventh edition of Gray’s Manual. * Contribution from the Botanical Laboratory of the University of Michigan, no. 136, The part of this work done during the summer of 1912 was carried on with the aid of a grant from the American Association for the Advancement of Science. 445 446 © BOTANICAL GAZETTE [pone General discussion In order to maintain existence, it is necessary for an organism to fulfil the fundamental requirements of life; it must be able to take in food; it must be able to digest its food; it must be able to oxidize or otherwise rearrange its substance to obtain energy; it must be able to eliminate its waste products; and it must be able to perpetuate its kind. Further, it must be able to’ perform all these functions in its particular, individual environment. As these individual plants cannot migrate, they must be able to accom- modate themselves to the changing environmental conditions or die. That they flourish from year to year in healthy condition is unquestionable evidence that they are able to cope with their environment. Their ability to invade genetically lower associa- tions of plants indicates that they are thriving rather than just merely existing in their habitat. Although a living plant is always the expression of the inte- gration of environmental and hereditary factors, the most important single factor in the environment is the physiological water supply. The modifications of plant structure which lead to the conser- vation of the water supply are termed xerophytic adaptations or xerophytic reactions. The presence of xerophytic adaptations does not necessarily predicate that the amount of water used by the plant is relatively small, but that the ratio of the amount used to that which the plant obtains tends to become less than unity . Some so-called xerophytic plants use as much or more than ordi- nary mesophytic plants, as Groom (20) found was the case with Larix decidua. They are xerophytic, however, because they cannot absorb a large amount of water in proportion to that which they could otherwise transpire. : This is particularly true in the summer, when plants have their transpiring organs. The loss of leaves during the winter is quite rightly regarded as a xerophytic adaptation. The bog ericads which were investigated, however, retain their leaves during the winter. This opens at once the question, are these plants xerophytes because of their summer or their winter environment? As it may be safely assumed that the evergreen habit is hereditary in these ericads, the reaction to the environment necessitates the xerophily. 1914] GATES—X EROPHILY 447 It would seem, at first glance, that plants which grow in bogs, where there is an obvious physical water supply, would not be restricted in its use, but the various xerophytic adaptations argue for the conservation of water in the plant. This fact led investi- gators to ask why the plants could not make full use of the water present. Many answers have been attempted, and it seems quite likely that the true answer is a combination of the different reasons rather than any one. The problem presents an obvious result obtained from a bewildering mass of causes, whose interactions are not yet known. The ability of peat bog plants to absorb water is limited on account of poorly developed, shallow root systems (FRUH and SCHROTER 18), low oxygen content of the water (DACHNOWSKI 9 and HEssELMANN 23), low aeration (TRANSEAU 49, DACHNOWSKI to, and FREE 17), root excretions (Livincston, BrirTon, and REID 27, and ScHREINER and REED 45, 46), bog toxins (LIVINGSTON 29 and DACHNOWSKI 9, 10, 11), the necessity of mycorhizal fungi in some species, the low temperature of the soil water (KOSAROFF 25, Fru and Scurérer 18, and especially TRANSEAU 49), and biological processes rather than chemical differences in the soil (DAcHNowski 12). Much stress cannot be laid upon the acidity- of the soil, as has been done by ScuimPER (44), because of the find- ings of later investigations. The acidity is very low and differs in different bog associations (TRANSEAU 49). That acidity is a neces- sary factor in the soil for the growth of trailing arbutus (Epigaea repens) and of the blueberry (Vaccinium corymbosum) was most admirably demonstrated by CovittE (6, 7), who found that poor aeration was usually the real cause of poor growth and not acidity. Acidity, however, may be inimical to certain crops. Sampson and ALLEN (42) found that, as a rule, some of the common acids acceler- ate transpiration, and that weak solutions often produce as marked effects as strong ones. The water absorbed is conducted up through the stems. A study of stem structure would show whether the ericads differ essentially from other bog shrubs. In either case the ability to conduct water must be adequate, as the plants thrive. From the stem the water passes into the leaves, where the largest 448 BOTANICAL GAZETTE [JUNE part of it is vaporized and passes out of the plant through the stomates. Xerophytic responses may be classified into means retarding transpiration in the leaves or transpiring organs, absorption in the roots, checking transportation in the conducting tissue, or pro- vision for an accumulation of water. In the peat bog ericads used during the course of this investigation, xerophytic response is very evident in the leaves, but is not accompanied by water storage tissue, which makes the xerophytic structure more necessary on account of the poorly developed root sytem. The evergreen habit, with its relatively large exposure of leaf surface, calls for greater activity of the root system throughout the winter, for transpiration still continues even when the thermometer is below zero. That means to reduce the loss of water are all the more necessary under winter conditions is obvious. Seasonal history of peat bog plants EVERGREEN ERICADS During the winter the leaves of all of the evergreen ericads: Chamaedaphne calyculata, Andromeda glaucophylla, and Vaccinium macrocarpon, are upright, a position in which they receive a mini- mum of direct sunlight. The leaves are dark red or brown in color. With the coming of spring the old leaves curve outward or down- ward, resulting in an increase of the direct sunlight which they receive. At the same time the leaves become dark green in color. The season’s growth of young leaves takes place soon after flower- ing. At first the young leaves are upright, but in a short time they bend outward. As soon as the young leaves are fully developed, the old leaves gradually drop off. In the case of Vaccinium macro- carpon, however, some of the leaves may be retained for two or three. years. With the coming of the next winter, the leaves of these plants gradually bend up into an upright position and their color changes from bright green through dark green to shades of red and brown. The color changes begin at the margins of the leaves and work toward the midribs. In a mild winter the basal portion of midribs of Chamaedaphne may remain green the entire winter. Vaccinium and Andromeda are usually protected by a covering of 1914] GATES—XEROPHILY 4409 snow, but they exhibit these changes of position and color irre- spective of that fact. DECIDUOUS TREES AND SHRUBS The principal trees are Larix laricina and Acer rubrum, and the commonest shrubs are Aronia melanocarpa, Salix pedicellaris, S. discolor, S. sericea, Spiraea salicifolia, Betula pumila, Nemopanthes mucronata, Ilex verticillata, Gaylussacia baccata, Cornus paniculata, Cephalanthus occidentalis, Sambucus canadensis, and Rosa carolina. During the winter, bog trees and shrubs are leafless, which greatly reduces the transpiration. The snow that is present during the winter protects the root system and lower part of the stem from danger from excessively low temperature, but the upper parts of the trees and shrubs are not so protected. They must be able to resist water loss through their own modification. This is suffi- cient for the severest winters in southern Michigan. During the winter of 1911-1912, Spiraea was the only deciduous shrub to be killed down to the snow line. With the opening of spring the buds swell and develop into branches bearing leaves which carry on the work of the season. A separation layer is formed upon the approach of winter at the base of the petiole, and by the time winter has set in the leaves have fallen. HERBACEOUS PLANTS The seasonal history of the herbaceous bog plants follows two general lines: the plant which has developed during the growing season may die down completely before winter, leaving seeds to reproduce it the following year, or it may die down to the ground and be vegetatively reproduced the following year from under- ground stems, bulbs, rootstocks, or buds. Any of these ways is an absolute xerophytic adaptation on account of winter conditions, but does not interfere with summer development. Structure of certain peat bog plants ROOT SYSTEM Without exception, all of the forms dealt with had a very shallow root system, which was usually very poorly developed. It is in direct contrast to that of the xerophytes of the desert (CANNON 4). 450 BOTANICAL GAZETTE [JUNE Two general types of roots could be separated, according to the presence or absence of mycorhizal fungi. Most ericads have mycorhiza, but none were found upon the roots of Andromeda or Chamaedaphne. In working over the material furnished him by the author, McDoucatt found that Andromeda occasionally gave evidences of mycorhizal appearance, although further investigation failed to reveal its presence. Mycorhiza was found on Larix lart- cina, Acer rubrum, and Vaccinium macrocar pon, but was not noticed on any of the following plants: Carex filiformis, Sagittaria latifolia, Eupatorium perfoliatum, Dulichium arundinaceum, Asclepias in- carnata, and Aspidium thelypteris. The absence of mycorhiza on Chamaedaphne and these other plants demonstrates that it is not a necessary adaptation to the bog environment. The presence of resin deposits (TRANSEAU 49) is often a noteworthy feature of the roots of bog plants. Root hairs were not observed, although TRANSEAU (49) found that in culture solutions, which were well aerated, normal roots with root hairs were produced in Larix. During the summer, the roots of the bog plants, at least appar- ently, have an abundant water supply, although as a matter of fact the Sphagnum which surrounds the roots may be physiologically dry, even when apparently wet, on account of its great ability to soak up and retain water (Fri and ScHROTER 18, and Davis 14). In general, however, there is standing water beyond the ability of the Sphagnum to absorb, and therefore the bog plants have a supply to draw on throughout a normal season. Seasons of drought, therefore, would be the critical ones, and that of 1911 was a case in hand. In so far as could be observed, it did not appear that the ericads were suffering from lack of water even on the hottest and driest days. The leathery nature of their leaves makes it nearly impossible to tell whether the plants are wilting or not, even when herbaceous vegetation was obviously wilted. In the natural dis- tribution of these plants, droughts are not sufficiently extreme nor of sufficient duration to dry out the Sphagnum. The great ability of Sphagnum to soak up and retain water localizes the water within reach at the expense of the surrounding area. During the summer this often results in the elevation of the water table 1914] GATES—XEROPHILY 451 under the bog several inches above that of the surrounding country. Taking into consideration the rarity of real drought conditions of long duration, it is evident that the root system in the bog habitat is able more than merely to maintain these plants within their normal range throughout drought conditions. The xerophytic adaptations of the transpiring organs, of course, materially aid by lessening the demand upon root absorption. During the winter the ground is normally frozen. On account of the low position of bogs, they are more subject to early and late freezes than the surrounding country. Although the ground may be frozen, the covering of snow prevents the access of very low temperatures to the roots. In spite of the fact that the ground is frozen, it is evident from the continual water loss of the above- ground parts that some water is being absorbed by the roots, quite likely the water vapor evaporated from the ice into the spaces which become opened around the roots soon after the freezing of the ground. At any of the temperatures at which roots were dug up (down to —10° C.) it did not appear that any part of the plant was frozen. All parts were pliable to handling. The exposure of severed parts of Chamaedaphne for one-half an hour to —25°C. resulted in freezing and loss of pliability. It was repeatedly noticed that the leaves which had been exposed to the severest weather of the winter, including a temperature of —29° C., were dry, and cracked when bent. Later it became evident that these leaves had been killed. Beyond this simple test, whose limits of accuracy are not known, there were no suitable means of determining in the field whether the plant tissue was frozen. CONDUCTING SYSTEM The conducting system in bog ericads consists of a very narrow ring of young xylem just outside the old wood (fig. 1). There is a very striking similarity in the appearance of the cross-section of the three ericads studied. The type of stem represented in bog ericads is strikingly different from that of other bog shrubs in the relatively smaller amount of conducting tissue and in the smaller 452 BOTANICAL GAZETTE [JUNE lumina of its cells. In this respect bog herbs are all different from the bog ericads also. Among the bog shrubs the ericad type stands out distinctly from all the other shrubs, there being far less differ- ence between the structure of any two ericads than between an ericad and any other bog plant. Just how the water is conducted from the roots to the tran- spiring organs is not a closed question. For a discussion of it the reader is referred to the literature, particularly CopeLANp (5), Drxon (16), OvERTON (37), RENNER (41), SCHERMBEEK (43), and BABCOCK (1). The results of this investigation show that the fundamental control of rate of conduction is exercised by tran- spiration. An increase of transpira- tion always means an increase of conduction, and a decrease in tran- ste ee sienatiik of spiration means a decrease in con- the stem of Chamaedaphne caly- duction, though not always in the culata: the dark outer ring is cor. Same proportion. Absorption and tex, just within it is the medium conduction are more closely related nary Se to each other than to transpiration, center the pith. and they are more closely related to the turgidity of the cells than is transpiration. By reducing the turgidity of the cells transpira- tion exercises a control over the other two. UTILIZATION SYSTEM Although the external appearance of the leaves of various peat bog plants is very different, the general internal structure is more nearly similar, and that of the various ericads is still more alike. Several well marked xerophytic adaptations are present, notably the strongly cuticularized epidermis, absence of stomates on the upper surface, a well developed palisade layer one to three cells thick, frequently sunken stomates, and coatings of wax, bloom, hairs, or scales. Mechanical tissue is present and accounts for the suppression of the ordinary symptoms of wilting. Usually the 1914] GATES—X EROPHILY 453 leaves are at least slightly revolute, those of Andromeda and Salix candida strongly so. The leaves are usually dark green in color, but often reddish at the beginning and close of the vegetative season. The abundant presence of cutin in the evergreen ericads as an efficient xerophytic adaptation against loss of water at all times, but especially in winter, has been brought out by WIEGAND (51). A considerable amount of water is transpired by many bog plants, and the loss may be as great as or greater than that from mesophytic plants of the same vicinity. This suggests that it is e€ maximum rate to which the plant may be subjected rather than the amount of water lost that is the important consideration. If the amount of food material is correlated with the amount of water lost, there would have to be considerably more water absorbed in the bog habitat, as it is notably deficient in available mineral food material (TRANSEAU 49). Plants that normally grow in non-bog conditions, as white pine and black spruce, when growing under bog conditions are much dwarfed and stunted, and their leaves exhibit very pronounced xerophytic modifications, so much so that these plants growing in bogs have received specific designation. Some plants, as Populus tremuloides and Poa pratensis, that may grow in either bog or mesophytic soil, do better in the latter situation and always exhibit a pronounced xerophily in the bog soil. Some plants demand bog conditions and even then have xerophytic modifications, as COVILLE (6) demonstrated in the case of the blueberry. During the growing season, all of the bog plants have their transpiring organs, but the great majority do not retain them during the winter. In every case where leaves are retained, their winter position is different from their summer one. The winter position is usually upright, but in the evergreen conifers the leaves are more closely appressed to the twig. The young leaf as it comes out in the spring is also upright and remains so at least as long as it is tender. The fact that the dark upper surface is innermost when the leaves are upright serves to protect it by reducing the amount of radiant energy absorbed, which would raise the temperature of the mesophyll cells and lead to greater loss of water. The under sur- face is already well protected. The upright, upper surface to upper 454 BOTANICAL GAZETTE [JUNE surface position of the leaves during winter is really a xerophytic modification, reducing the amount of radiant energy absorbed at a time when it would be needlessly dissipated in increase of water loss, which the absence of phytosynthesis and the closure of the stomates does not occasion. Leaves which develop upon Chamae- daphne in the Larix association are much less xerophytically modi- fied. They are much more subject to winter killing. The loss of water by the leaves exercises a twofold function. The excess of radiant energy absorbed and not used in photosyn- thesis could easily raise the temperature of the leaf to the death ‘point during hot waves, were it not dissipated in vaporizing water. Darwin (13), through the use of a resistance thermometer, demon- strated that, with the check to transpiration that comes with induced closure of the stomates, the temperature of the leaf rises. Normally this higher temperature would not occur, for the excess of radiant energy being used to vaporize water causes a lowering of temperature. The loss of water in the leaves maintains a stream of water from the roots up. This is necessary for the removal of the products of respiration (BABcocK 1) and for the lifting of the absorbed mineral material to the leaves. Water is also necessary in photosynthesis. As Livincston (30) puts it: ‘‘The total amount of tran- spirational water lost from a plant, for any given period, may be considered as a summation of the effects of the evaporating power of the air and of the radiant energy absorbed throughout the period, modified by certain secondary effects of these conditions and certain responses to other conditions.’’ The ratio of the water income to that of the removal must not fall below unity for any considerable time in plants which are not water-storing. Quoting again from LIvINGSTON (31): “The really crucial question with regard to any soil . is... . at what rate, and for how long a time, can it deiner wale to a unit area of a water-absorbing surface?” That water is supplied in sufficient quantities during the most extreme conditions of summer that obtain in nature in this region is evident from this investigation. The opposite statement is true for winter, namely, that in very severe winters the removal of water from the exposed parts of certain plants is so in excess of the supply that too 1914] GATES—X EROPHILY 455 thorough drying and therefore death result. This same process has already been shown by KiHitMAN (24) to be the cause of the arctic tree line. That the water supply for ericads in Michigan peat bogs is actually ample to their needs is clearly demonstrated by experi- mentation upon potted plants, for even under the very extreme evaporating power of the air on July 5, 1912, the maximum rate of transpiration was contemporaneous with the maximum evapo- rating power of the air. Conditions of atmospheric evaporating power in Michigan are never as high as those of Arizona, where Lioyp (32) found that the fall in the rate of transpiration in oco- tillo (Fouquieria splendens) occurred before that of the maximum evaporating power of the air. Whether these results may be the true expression of the behavior of rooted plants may be open to question, as Lioyp used cuttings to experiment with. It was found in the present investigation that on days of extreme evapo- rating power in Michigan a decline in the transpiration rate in advance of the time of maximum evaporating power of the air did actually occur in cuttings, but was not exhibited in potted plants of the same species. Such a check in transpiration is occasioned by what Livincston and Brown (28) have termed ‘incipient drying,” in the course of which the evaporating menisci have retreated into the pores of the cells, thereby not only decreasing the amount of the exposed surfaces, but also greatly increasing the surface tension of these evaporating surfaces, which decreases the vapor tension and consequently the rate of vaporization (RENNER 39, 40, and PatreNn 38). The increase in the concentration of cell sap which accompanies this check in water removal further retards vaporization. A very serviceable pictorial presentation of the matter is given by MacDoucat (34). The recent work of some investigators seems to withdraw the foundations from the theory of the efficient function of the stomates as the regulators of transpiration (LLoyvD 32, 33, and others). That closed stomates are efficient means of lowering transpiration has been demonstrated by many authors (BURGERSTEIN 3, and Deir 15). The closure of the stomates of evergreen plants during winter, which has been demonstrated by several investigators, 456 BOTANICAL GAZETTE [JUNE especially STAHL (47), is an important factor in reducing tran- spiration at that season, when the water intake is at best very low. The work of Lioyp (32) on Fouquieria led him to conclude that the capacity of the diffusion of the stomates was well in excess of what would be required for the greatest observed transpiration rate. F. Darwin (DELF 15), in a preliminary account before the British Association, concluded that if the stomates can be observed by a sufficiently delicate method, the stomal movements will be found to correspond closely with changes in the rate of transpiration caused by alteration in external conditions. In the present investigation, in which the method of relative time of penetration of an oil was used to indicate the condition of the stomates, there was no evidence that the stomates exercised “closely regulatory” function. The stomates opened in the morning, in general in the diffused light of dawn, but the rate of transpiration showed no sudden rise, but rather kept proportional to that of the evaporating power of the air. In the afternoon the stomates did not begin to close until after the beginning of the decline in transpiration. This was true both in potted plants and in cuttings properly cared for on days that were not extreme. In many cuttings the closure of the stomates seemed to be due to the shock of cutting rather than to any excessive water loss. Almost all of the wilted plants had their stomates closed, but in dried leaves the stomates were open. The experimentation on plants in the field led to the conclusion that the stomates were open during the hours of sunshine, and that, although the opening of the stomates preceded the rise in tran- spiration in the morning, the decline in transpiration set in in the afternoon before the beginning of closing of the stomates. The rate of transpiration sank more quickly to a lower level than the time it took the stomates to close could possibly account for. Experimentation MATERIALS AND METHODS? Throughout the study of this problem an experimental method was used which yielded numerical data. The experiments were carried on upon bog plants, principally: Chamaedaphne cane 2 Cf. BURGERSTEIN 3. ro14] GATES—XEROPHILY 457 (L.) Moench, obtained from First Sister Lake, a little west of Ann Arbor, Michigan, and at Mud Lake in the northern part of Washte- naw County, Michigan. Toward the close of autumn in 1o1o0 and 1o11, plants of the evergreen ericads were potted and kept outdoors under prevailing conditions. During the middle of winter their transpiration was determined by successive weighings on a beam balance sensitive to 0.002 gram. The pot was inclosed by an aluminum shell (devised by GANonG) closed at the top with rubber dam and sealed with wax, whereby the water loss was limited to the plants, as controls repeatedly demonstrated. Readings of weight to 0.01 gram, temperature by mercury thermometer and thermograph, relative humidity by wet and dry bulb thermometers, and general conditions of the weather were recorded. A number of pottings of ericads and other shits were made at First Sister Lake, June 1, 1912, the plants allowed to develop under bog conditions, and experimented upon the first week of July 1912. By far the greater part of the work, however, was conducted with cuttings. These were made from the plants at First Sister Lake, immediately cut under water in jars and brought into the laboratory where they were again cut under water. The cuttings were then set up in two-holed rubber corks in bottles of distilled water and sealed with vaseline. A thermometer inserted in the other hole of the cork gave the temperature of the water. Work with controls proved that the apparatus was water-vapor tight. Usually about one-half an hour was allowed for adjustment before measurements were commenced. Weighings were made at intervals of one, two, or more hours, according to the purpose of the experi- ment. Such experiments were seldom carried over 24 hours, except for special reasons. The day of 24 hours of 100 “‘minutes” each was used in recording experiments, because of its obvious convenience. Some plants which were transplanted into the greenhouse in Sphagnum did so poorly that no experiments were made upon them. Shoots that developed on cut twigs kept in water in the laboratory or greenhouse seldom lived more than a couple of weeks, and as their internal structure was not normal, no experiments were per- formed upon them. 458 BOTANICAL GAZETTE [JUNE It was found that different Chamaedaphne plants from the Chamaedaphne association (fig. 2) transpired at virtually the same rate during the same experiment. Consequently, that plant was taken as the basis for all comparisons and was included in practically every set of experiments. With the close of the experiment the leaves were detached, placed side by side on white paper, covered with a thin piece of glass, and their outlines traced with a polar planimeter, by which means the leaf area was obtained. After a little practice with this instrument it was found that successive determinations of the same set of leaves did not vary by as much aso.3 percent. Accord- ingly the average of two determinations was used throughout the work. When stomates were also present on the upper surfaces (the rare exception in the plants used), the area thus obtained was oubled. With the data so recorded, the results of each experiment were calculated with the aid of a slide rule to a standard basis, the rate of transpiration in grams per hour per 100 sq. cm. of leaf surface. These results were plotted on cross-section paper and the com- parison made. As more than one determination for each plant was made, the resulting curves should approach a general simi- larity. Under the same conditions the similarity of the graphs was striking. Through dissimilarity of the resulting graphs, it was possible both to demonstrate the effect of change of experimental conditions and to weed out aberrant plants. As the greater part of the work was concerned with relative values, the continued reappearance of the same result in the graphs was taken to uphold the contention and no contention not thus uniformly upheld is presented in this paper. During a part of the year 1912 the volume of the leaves was also determined by ascertaining the amount of alcohol they displaced. Alcohol was used in place of water on account of the large amount of air coating the leaves submerged in the latter. The results were calculated on the basis of water loss per hour per 1 cc. of volume. This was done in order. to incorporate the results obtained from plants, the difficulty of determining the leaf surface of which would otherwise have rendered it virtually impossible. The correlation 1914] GATES—XEROPHILY 450 of volume and leaf surface was irregular. With leaves of about the same size and thickness, the amount of water loss varied pro- portionally. In plants of Chamaedaphne from different plant associations, where both size and thickness of the leaves varied (fig. 2), it did not usually appear that volume was any constant function of the leaf area. While it is recognized that the measured leaf area is not the area of the water-losing mesophyll cells, it is believed that it furnishes Fic. 2.—Twigs of Chamaedaphne calyculata, showing the character of the leaves developed in the Larix association (bottles 1 and 2) and in the Chamaedaphne asso- ciation (bottle 3), at First Sister Lake; April 29, 1911. a satisfactory basis of comparison attained without the excessive difficulty that would attend the determination of the actual area of the surface abutting upon the intercellular spaces. The leaf surface, moreover, is the area through which the diffusion into the outer air takes place. To obtain a knowledge of the evaporating power of the air an open dish of water was run with several of the experiments. At the close of many of the experiments a section of the small- est part of the stem below any transpiring organs was cut out, 460 BOTANICAL GAZETTE [JUNE preserved in glycerin-alcohol, later sectioned, and stained with iodin green to show the area of the conducting system. By means of the lithium nitrate method, which consists of cutting off the lower ends of leafy stems under a o.5 per cent aqueous solution of Li(NO,)., allowing the stems to take up the solution, removing after certain intervals, and cutting immedi- ately into 1 cm. lengths, testing these pieces in the spectroscope for the presence of lithium, a knowledge of the rate of conduc- tion under different conditions was obtained. This method only approximates the rate of conduction in rooted plants, which could not be used because of inability to know when the lithium nitrate would be absorbed by the roots. The difficulty of examining the stomates of Chamaedaphne by the ordinary method of stripping and the consequent uncertainty of its results with this species led to the abandonment of work on stomates until the publication of a new method (Mo.iscH 35) opened the way for experimentation upon this pertinent question. The “infiltration method,” as it is called, depends upon the fact that when a leaf is wetted with a penetrating liquid, such as abso- lute alcohol, xylol, or turpentine, and held up to the light, it becomes translucent as soon as the liquid has penetrated the leaf. The relative time that it takes the leaf to become translucent after the application of xylol indicates whether the stomates are open or closed, because the more the stomates are open, the easier and quicker will the liquid penetrate the tissue and the sooner will it become translucent. A “normal” time must be determined for each species upon which to base deviations. Xylol was used throughout the present work, and the results were checked up with absolute alcohol and turpentine. As the method is so very simple, it can be employed in the field and several determinations made each time. The results were remarkably uniform. EXPERIMENTATION DURING THE WINTER Transpiration During winter the transpiration of the plants of the region is reduced to a serviceable minimum which, however, is not zero (cf. Kusano 26). For herbaceous plants the minimum is lower 1914] GATES—XEROPHILY 461 than for shrubs and trees. No experimentation was performed upon herbaceous plants during the winter, for it is known how exceedingly small is the amount of water loss from seeds, and as the vegetative means of reproduction employed by other herbs are December 1911. in 5 6 ‘Bre/o en® et hel @ © ‘ s LY iste 100 -090 °o 3 oooooce=* ooo” aaeeee Relative Humidity. Transpiration of Cuttings in the Greenhouse Fic. 3.—Transpiration of cuttings of Acer rubrum, Andromeda glaucophylla, Chemesdcaie: calyculata, L arix laricina, Nemopanthes mucronata, Salix pedicellaris, and Vaccinium macrocar pon in the greenhouse underground and thoroughly protected from exposure, no com- parison could be made with the ericads which retain their plant body subject to constant exposure throughout the winter The purpose of the winter experimentation, therefore, was to obtain a knowledge of the transpiration of several of the shrubs and trees, and compare that of the leaf-retaining ericads with that of the deciduous shrubs, under winter conditions outdoors and under 462 BOTANICAL GAZETTE [JUNE laboratory conditions which simulated the severest conditions which could obtain in nature during the winter. Experimentation was carried on both with potted plants and with cuttings indoors and outdoors. A few of the graphs obtained from the data from these experiments are given in figs. 3-6. Although they have been selected from the general array of data to avoid needless repetition they represent the general conclusions, not merely special cases. Consideration of these data clearly indi- cates that the transpira- tion of these bog plants January 1912. 1.8. OA ek 2e ee IS = aeee ~ -140 g/hr/100 om? 120 Qhamaedaphne calyculata ——— a . a a is very low in winter. Yeccinium macroca en Furthermore, ° with scarcely an exception, the rate of water loss is much greater (2-15 times) in the evergreen ericads than in the leaf- less shrubs and trees. When the very much —_ Snow thane Cy gy Snew Car Seed mre Exposed position of Transpiration of Potted Plants Outdoors. the deciduous trees and oe most of the deciduous dudvonide ene ic aa mS piesa — nese oe 5 and Vaccinium macrocar pon outdoors in winter. count, the difference in the rate of transpiration in nature is accentuated. The mere position of the ericads near the ground serves to reduce water loss. This same relation holds among the ericads themselves, namely, that the greater the rate of transpiration under given conditions, the more protected is the position in which that species grows. For example, Chamaedaphne transpires at a lower rate than Andromeda and Vaccinium; and Chamaedaphne, because of its higher growth, is more exposed. Yapp (52) has shown that the nearer the ground in a closed associa- tion the lower the evaporating power of the air. These data support the well known facts that transpiration — mo Se OR Ot Semen me . ——<—- aa uw n oo ‘© 1909. 11. ————, Physiologically ae habitats and drought resistance in plants. Bor. Gaz. 49 325-330. , The relation of Ohio ie estat to the chemical nature of peat soils. Bull. Torr. Bot. Club 39:53-62. 19 13. Darwin, F., On a eacmianion metho cold to the movements of stomata. Ror. GAZ. 37:81-105. 14. Davis, C. A., Peat. Report te Sunny Michigan. 1906 and 1907. 15. Der, E. MaRios, Transpiration in succulent plants. Ann. Botany 26: 409-442. 19 BOTANICAL GAZETTE [JUNE . Drxon, H. H., Transpiration and the ascent of sap. Prog. Rei Botanicae 3:1-66. 1909. . FREE, E. E., Soil water and the plant: Studies in soil physics, 3. Plant World 14: Waite IQIt . Frtu, J., und ScceGrek. C., Die Moore der Schweiz, mit Rerticksichti- gung der gesammten Masta: Bern. 1904. (Contains a special bib- liography of the subject of peat bogs.) Gates, F. C., The relation of snow cover to winter killing in Chamaedaphne SEE, Torreya 12:257-262. Groom, P., Remarks on the le of the Coniferae. Ann. Botany 24:241-269. Ig10 . HARSHBERGER, 1. W., Bogs, their nature and origin. Plant World 12: 34-41, 53-61. 1909. ———, Phytogeographic survey of North America. Die Vegetation der Erde. no. 13. IgIt. . HEssSELMANN, H., Uber den Sauerstoffgehalt des Bodenwassers und dessen - Einwirkung auf die Versumpfung des Bodens und das Wachstum des Waldes. Silva 4:65-66. 1011. (Review in Forestry Quarterly 9: 481. IQII.) . Kratman, A. O., Pflanzenbiologische Studien aus Russisch-Lapland. Acta Soc. pro Faune et Flora fennica 6:1890. Kosarorr, P., Einfluss verschiedener ausseren Pecteren auf die Wasser- -aufnahme der Pfla anzen. Inaug. Dissertation. Leipzig. 1897. w i) 34- Kusano, S., Transportation of evergreen trees in winter. Jour. Coll. Sci.” Imp. Univ. Tokyo 15:313-366. rgor. Livincston, B. E., Brirron, J. C., and Rem, F. R., Studies on the prop- erties of an unproductive soil. U.S. Dept. Agric., Bur. Soils, Bull. 28. 1905 Livincston, B. E., and Brown, W. H., Relation of the daily march of transpiration to oe in the water content of the foliage leaves. Bor. GAz. 53: 330. 309- . Livincston, B. E., Physiological properties of bog water. Bor. Gaz. 39:348-355- 1905. ———, Light intensity and transpiration. Bor. Gaz. 52:417-438. 1911. , Present problems in soil physics as related to plant activities. Amer. Nat. 46:294-301. 1912. . Luoyn, F. E., The — of stomates. Carnegie Institution of Wash- 8. ington, Publ. 82. e hia of transpiration and stomatal nivinients to the enbenccntent of the leaves in Fouquieria splendens. Plant World 1s: I-14. 1912. MacDovueaL, D. T., The water relations of desert meee Pop. Sci. Monthly 79:540-553. 1911. 1914] GATES—XEROPHILY 489 35- uo o @ Mo.iscu, Hans, Das Offen- und Geschlossensein der Spaltéffnungen, veranschaulicht durch eine neue Methode (Infiltrations-Methode). Zeitschr. fiir Botanik 4:106-122. 1912. . Oris, C. H., Measuring the transpiration of carts water plants. Thir- teenth Repait Mich. Acad. Science 250-253. QI - OvERTON, J. B., Studies on the relation of we living cells to transpiration and sap flow in Cosas: Bor. Gaz. 51:28-63, 102-120. IQII PaTTEN, H. E., On the relation of surface ae to SEN Se SES Trans. Amer. Electrochem. Soc. 19:359-380. 1911. - RENNER, O., Beitrige zur Physik der Transpiration. Flora 100:451- 547- I9QIo. Cs) ———,, Zur Physik der Transpiration. Ber. Deutsch. Bot. Gesells. 29: 125-132. IQII - Experimentelle Beitrage zur Kenntnis der Wasserbewegung. Flora on 173-247. SAMPSON, A. W., aoe Mee L. M., Influence sees physical factors on tran- spiration. Minn. Bot. Studies 4:33-39. CHERMBEEK, Uber die Krafte welche iss ae des Wassers in unseren Nadelhélzern und Laubhélzern verursachen. Allgemeine Forst- u. — 1911:204. (Review in Forestry Quarterly 9:478. ai S Rr, A. F. W., Plant geography upon a physiological basis. Oxfor 1903. SCHREINER, O., and REED, H. S., Some factors influencing soil fertility. US. Dept. Agee Bur. Soils, Bull. 40, 1907. , The production of ese excretions by roots. Bull. Torr. Bot. Club 34:279-303. 1907. STAHL, E., Einige Versuche iiber Transpiration und Assimilation. Bot. Zeit. 70: wee 1894. TRANSEAU, E. N., On the geographic distribution and ecological relations Gaz of the bes sink societies of North America. Bor. . 36:401-420. 3+ , The bogs and bog flora of the Huron River valley. Bor. Gaz. 40:351-375, 418-448, 1905, and 41:17-42. 1906. WARMING, E., Oecology of ‘oiendi: kook: 1909. (Contains an extended page ) Wiecanp, K. M., The relation of hairy and cutinized coverings to tran- sacar Bor. Gaz 4p 49:430-444. Igto. - Yapp, R. H., On stratification in the vegetation of a marsh, and its rela- tion ss evaporsiiod and temperature. Ann. Botany 23:275-319- 1909. Brown, H. T., and Escomsg, F., Static diffusion of gases and liquids in relation to the assimilation of carbon and translocation in plants. Ann. Botany 14:537. 1900. THE MORPHOLOGY OF ARAUCARIA BRASILIENSIS Il. THE-OVULATE CONE AND FEMALE GAMETOPHYTE L. LANCELOT BURLINGAME (WITH PLATES XXV-XXVII AND TWO FIGURES) In a previous paper (1), the writer has described the source of the materials used in this investigation and the methods used in their preparation. Nothing need be added to the details presented in that paper except to mention the fact that there have been wide variations of weather conditions here in the last four years during which these collections have been made. Considerable differences have been noted in the stages reached at the same dates during these years. The 1g10 collections appear to be two weeks or more farther advanced than those of the next year. It is not easy to be sure of the facts in regard to this, for cones from the same tree taken on the same day often vary astonishingly. It may be, con- sequently, that the variations observed are purely fortuitous and would not be sustained if the observations were sufficiently numer- ous, although I am inclined to think they would be. If so, it would appear that a wet winter is decidedly favorable to early develop- ment. The collections of ovulate cones were made about once a week throughout three years for most of the seasons, but were made every day or two during the months of March and April. Each ovulate cone is borne at the end of a short branch. From three to five such branches commonly occur at a single whorl of branches (text fig. 1). The rudiments of these cone-bearing branches and that of the central leafy shoot are formed within the terminal bud of a branch. They can be found by dissecting such a bud from which the daughter buds are beginning to emerge in early April or late March. I was unable to find any recog- nizable trace of them earlier. Although buds exist within such terminal buds earlier, I did not succeed in finding any means of distinguishing between cones and ordinary leaf buds until just before the swellings of the ovules make their first appearance. Botanical Gazette, vol. 57] , [490 1914] BURLINGAME—ARAUCARIA BRASILIENSIS 491 The buds all look alike externally before this, and even on dissec- tion are so much alike as not to be distinguishable. A branch that has borne a cluster of cones one year does not ordinarily —The tip of a fruiting branch bearing 6 young cones about 4 months old: the ee was made about August 1; 4 of the 6 cones are borne on branches arising from the same whorl, the other 2 ioe the whorl below; the whorl just out of the bud consists of leafy branches only; 3. bear a crop the next season. A cone-bearing branch is usually thicker and looks more vigorous than a leafy branch in the spring. When the cones have emerged from the terminal bud and are 492 . BOTANICAL GAZETTE [JUNE clearly recognizable as such, they are about the size of an English walnut. They are now distinguishable from a leaf bud by their shape, by their lighter color, and by the more numerous and -slenderer leaflike sporophylls. Pollination occurs at this stage. In 4 months they have reached the stage shown in text fig. 2. They are then 6-7 cm. long and about 5 cm. in diameter. The Fic. 2.—Cones of three different seasons, photographed in August: the smallest cone is 4 months old; the large cone is 16 months old; the cone axis with a few scales at base, 28 months old; the last shed its seeds in the preceding December and the largest cone would have shed seeds in the following December; X ;°:. cone is rough and prickly from the turned-back tips of the sporo- phylls. The seeds are shed the fall or winter of the next year, when the cone has reached a length of 12-18 cm. and has shed many of its prickles. The life of an ovulate cone is thus somewhat less than two years. This is about a year less than that reported for Agathis (3), and also less than that of most conifers. There are usually 400-500 sporophylls on a cone (text fig. 2). They are arranged in steep spirals, making rather more than 1.5 complete turns. 1914] BURLINGAME—ARAUCARIA BRASILIENSIS 493 Very soon after the cone is externally recognizable, the sporo- phylls show the first signs of the meristem that forms the ovule. At this time the sporophyll differs from a leaf in being differentiated into two regions. The outer part is slender and leaflike, while the basal portion is colorless, short, and stout, and tapers back slightly. The meristem is developed on the adaxial surface in a median posi- tion close to the base. It consists of many cells and grows rapidly. Figs. 1-3 show various views of it about this time. Although growth takes place throughout the sporophyll, yet four distin- guishable meristems are established that determine its ultimate shape and form. The first of these is the meristem of the nucellus, already mentioned. As soon as it has made a beginning, another secondary meristem arises as a curved band across its upper sur- face. This curved meristematic band has its convex side directed toward the cone axis. By its growth is produced that part of the integument free from the scale. It is continuous below with the meristematic region of the scale located at its base. The fourth meristem is also a curved band, with its convexity directed toward the tip of the scale. It produces the ligule. Not more than one sporophyll in twenty is fertile. Of those that do form ovules, many fail to mature them. Whether this tendency to sterility is equally marked in the native habitat of the tree I have not yet ascertained. It seems not unlikely that it may be due to the effects of cultivation in an alien habitat differing con- siderably from that of the highlands of Brazil. It has nothing to do with pollination, I am convinced, for all the cones are abundantly pollinated, both sterile and fertile sporophylls alike. The pollen tubes develop on the sterile ones, at least up to a length of 0.5 cm. or more. The meristems very quickly produce the ovular structures. On account of this fact, and the further fact that one cannot distinguish sterile from fertile sporophylls until after sectioning them, I did not secure a complete series showing the development of the ovule. The outlines of the process, however, are clear. The basal meristem of the sporophyll elongates it, and the integument keeps pace. The result is a deep tubular cavity, deepest on the side next the sporophyll. At the base of this the nucellar meristem has been 404 BOTANICAL GAZETTE [JUNE elongating it to keep pace with the development of the integu- ment. The result is shown in fig. 6. The line of union between the integument and the sporophyll proper is clearly indicated. In being attached along the entire side to the sporophyll, the ovule of Araucaria presents a sharp contrast to that of Agathis, which is attached only at the base (6). | In the nucellus three regions are at this time distinguishable. The tip consists of large clear cells, more or less isodiametric. Below this region the cells are elongated in the direction of the axis of the nucellus and arranged in fairly distinct rows. The rows become less definite toward the base. In the central portion of the base of the nucellus lies a group of cells with larger nuclei and denser contents. The megaspore arises in the midst of this group. This probably corresponds to the spongy tissue of various conifers, though it does not behave in precisely the same way during the further development of the ovule. Further reference to it will be made below. The megaspore is picked out in a position above the bottom of the cleft between nucellus and integument. As it lies within the meristematic zone of the former, it follows that in the further growth of the ovule the female gametophyte will lie almost exclu- sively above the bottom of this same cleft. In this growth the nucellus does not enlarge its tip greatly. The result is that by the time the archegonia are ready for fertilization the nucellus is com- posed of a swollen base, containing the gametophyte, and a small extension above. The ovule at this time measures about 1 cm. in length and 3-4 mm. in diameter. The gametophyte extends through about half of it, and is about 1.5 mm. in diameter. It is somewhat oval in outline, with the archegonial end noticeably broader (fig. 4). The micropyle is shaped something like a human mouth, with its longer diameter transverse. Sometimes the upper lip is split back into a wide and deep V-shaped cleft extend- ing back half the length of the gametophyte. Occasionally the latter breaks through the tissues of the nucellus and is openly exposed in the region of the archegonia. The further growth of the ovule gradually transforms the whole structure of ovule and sporophyll into the seed. The changes involved will be discussed 1914] BURLINGAME—ARAUCARIA BRASILIENSIS 495 at another time. At maturity the gametophyte is 4-4. 5 cm. long, 2 cm. wide, and 1.5 cm. thick. ‘The entire seed structure is 5-6 cm. long, about 2.5 cm. wide, and 1.8 cm. thick. The megaspore mother cell appears about the middle of May in the upper part of the group of denser cells already referred to. A first it differs only in size. As it enlarges, the adjacent cells show signs of disintegration. Fig. 5 shows a mother cell in synapsis. To the right and to the left of it may be seen two cells that are being flattened and whose nuclei are apparently beginning to degenerate already. I secured only a few preparations of the early stages and so cannot say certainly whether more than one megaspore mother cell ever begins development or not. Unfortunately I did not observe the reduction of the mother cell for the same reason. The chromosome numbers would indicate that a reduction does actually occur. Fig. 6 shows the position of the megaspore. In fig. 7 there may be seen two small cells just above the functional megaspore, that are probably the remains of the other members of the tetrad. A similar group is present in fig. 8. Very early the -Megaspore becomes vacuolate, with the very scanty cytoplasm orming an extremely delicate lining to the embryo sac. The nucleus is flattened, yet its thickness is several times that of the layer of cytoplasm in which it lies. It increases its volume, but oes not immediately divide. Uninucleate embryo sacs are found in June, and binucleate ones (fig. 8) in July. By the latter part of the month as many as 64 nuclei may be present. Fig. 8 is that of a sac with two nuclei; in fig. 9 there are 8; and in fig. 10 a few less than 64. From this it would appear that the early divisions are simultaneous. As a matter of fact, I do not know that they _ are, for I have never observed a single mitosis in any of the more than 500 preparations of the free nuclear stages available for study. These preparations represent more than 50 collections of separate cones and two or three times as many separate ovules. It seems exceedingly strange that they should be so persistently missed. The same difficulty was encountered in a study made of the mitoses of the pollen mother cells (x). In that study I made the suggestion that those mitoses may occur at night. It has not yet been practi- cable to test out this hypothesis, and I mention it here merely 496 BOTANICAL GAZETTE [JUNE because I can think of nothing more likely. Saxton (5) has since met the same difficulty and has hazarded the same guess. It may be that the mitoses are both siniultaneous and passed through with extreme rapidity, and that it is merely chance that they have been missed. No indications of amitosis have been observed. Above the 64-nucleate stage the numbers are not regular, being usually somewhat less than the exact power of 2. Enlargement of the sac and multiplication of the nuclei continue up to the latter part of January. At this time there are more than 2000 free nuclei present. The cytoplasm still remains extremely scanty. Figs. 9-16 show the progress of development at intervals of about a month. In January a change in the method of development occurs. Without any considerable increase of nuclei, the cytoplasm increases rapidly. As soon as it has become somewhat thicker, vacuoles make their appearance. The result (fig. 17) is that the central cavity is surrounded by a rapidly thickening sac of vacuolated pro- toplasm, with the nuclei largely confined to the inner border (fig. 18), In many cases the walls between the vacuoles break through. leaving the inner plasma membrane connected to the outer one merely by tenuous strands. The nuclei usually lie at the points where these strands join the inner plasma membrane. A few are found at the outer membrane, especially at the micropylar end of the sac. The protoplasm is thicker at this end also. This process goes forward very rapidly. The inner border advances on the central vacuole and the nuclei multiply somewhat. They now pass out along the cytoplasmic strands (figs. 19-21). By the time the inner border has closed up on the vacuole completely (fig. 20), most of the nuclei have migrated outward. With the continued increase of the cytoplasm, most of it remains in the peripheral regions, especially near the micropylar end. It collects along the strands and plates until distinct uninucleate vacuolated sacs are formed. The nuclei are now generally sus- pended by still more delicate strands in the central portion of the sac. Fig. 22 shows how these sacs behave under the action of the killing reagents. Each sac appears to have its own wall of inclosing protoplasm capable of being separated from that of its neighbor. Mitoses now occur plentifully in preparations of the peripheral 1914] BURLINGAME—ARAUCARIA BRASILIENSIS 4907 portion of the prothallus. In this way there is formed a sort of colony of free cells closely packed together but yet capable of easy separation. This condition gradually passes into the vacuolated condition of the inner part of the gametophyte, in which region walls are not formed for some time. In fact, it never becomes so solid as the outer parts. In about a month delicate walls have ac their appearance between the peripheral cells (figs. 31, 32), though no definite cells have yet been organized centrally (fig. 25). The exact method of wall-formation was not made out. The process is remarkably sug- gestive of the way in which walls are formed in cleavage furrows in certain lower plants. One such cell is formed for each nucleus. After the formation of these first walls, the succeeding ones in the outer part are laid down on cell plates formed on the spindles in the ordinary fashion. The outer cells are generally uninucleate, while the central cells, after they have become walled off, become multi- nucleate by the time the archegonia are mature. They also later contain considerable quantities of starch. In the further growth of the gametophyte, walls are formed on the spindles in the outer portion after each mitosis; in the central region wall-formation does not occur at this time. The transition from one region to the other is very gradual, and the walls thin out so gradually that it is almost or quite impossible to tell where there are actual walls. In fig. 31 are shown mitoses of both sorts. The one near the archegonium initial will have a wall formed on the spindle, while the one near the opposite border will not. Cell plates are formed in connection with the mitoses even before any walls are being formed on them (fig. 24). In the central region the nuclei are sometimes situated at the intersection of the larger strands and plates of cytoplasm and sometimes are suspended by much finer strands in the central region of the vacuolated spaces. Sooner or later these spaces, like the peripheral ones, form walls in the inclosing plates of cytoplasm and become cells. At the time of their inclosure by walls, they are commonly uninucleate. Later they frequently contain as many as 4-6 nuclei. Up to the time of the maturity of the archegonia the cytoplasm in all the cells of the gametophyte remains very scanty. 498 BOTANICAL GAZETTE [JUNE The outline of the growing prothallus may remain smooth and even (fig. 36) or become very irregular (fig. 35). The irregularity © appears to be entirely due to two facts. The gametophyte, as already mentioned, is very delicate and plastic, and, in consequence, able to adapt its form to the cavity in which it grows. The second fact is that the cavity in which it is forming does not always enlarge regularly. Whether the irregularity is due in whole or in part to the action of the gametophyte is somewhat doubtful, as will be pointed out in the succeeding paragraphs. The development of the game- tophyte beyond the fertilization stage will be further described in connection with the maturity of the ovule and the organization of the seed. The cells surrounding the megaspore have already been men- tioned as being larger, having larger nuclei and denser contents than other nucellar cells. They perhaps correspond to the so-called spongy tissue. The character of these cells is shown in figs. 6-8. As the megaspore enlarges, the innermost layers of these cells die and lose their contents. ‘The walls also seem to disappear, though much more slowly. They are at first stretched out and closely compressed into a thick and compact band just outside the mega- spore membrane. Inasmuch as this band of crushed cells does not appear to increase in thickness beyond a certain point, it seems reasonable to suppose that it is dissolved and perhaps used by the growing gametophyte. Immediately outside of this region of dead and empty cells there is a more or less distinct band of cells (figs. 10, 12, 13, 14) which stain more densely. This band of cells devel- ops outward in advance of the gametophyte, keeping much the same relation to it as at first. The individual cells have more cell contents than the cells outside of the band. Their nuclei take basic stains strongly, as sometimes does the cytoplasm also. In short, they appear to be undergoing degeneration. The appear- ances described are such as have been observed in many other plants. The phenomena have been commonly ascribed to the effects of the gametophyte. It has been supposed that it secreted some sort of enzyme or other substance that diffused outward, killed and digested the cells, and prepared them for food for itself. It looks like a reasonable inference. 1914] BURLINGAME—ARAUCARIA BRASILIENSIS 499 In the preceding paragraph I have described the appearance of the nucellar tissues around the growing gametophyte. I wish now to describe some of the anomalous conditions found that have led me to suspect the validity of the current accounts of the effects of the gametophyte on the nucellus. In fig. 26 is shown an apparently enlarging hole in the nucellus surrounded by the two usual bands of differentiated cells. Such ovules are fairly common. In some cases the megaspore membrane appears to be present. One might infer in such cases that the hole is the work of a gametophyte that for some reason or other has died. In most cases the megaspore mem- brane cannot be demonstrated; but since it is not well developed in any case, this would not appear to be an insuperable difficulty. Fig. 27 shows a less common condition. There is no game- tophyte here, nor is there any place for one; yet there is a remark- able correspondence in nucellar structure. In the center there is an enlarging mass of cells whose nuclei and cytoplasm are under- going degeneration. The central cells are almost completely crushed; they have very little or no living contents. Outwardly the cells grade off through less and less crushed cells to a band of normal shape and size, but with densely staining contents, just as in the normal ovules. If there is no gametophyte and even no place for one, then the effects cannot be due to the presence of one. It seems that these facts admit of but one of two possible explanations: either the cells of the spongy tissue, which are possibly potential megaspore mother cells, are capable of producing the observed effects, or it is a quality of the nucellar cells themselves. to behave in this fashion, regardless of the presence of a gametophyte or its antecedent archesporial tissue. A noticeable peculiarity of these cells in all cases is the thickening of their walls accompanying the death and disappearance of the protoplasm. The development of such sterile ovules has nothing to do with pollination, apparently, for they occur regardless of whether the pollen has or has not sent tubes into the nucellus. They are rela- tively common and develop to advanced stages. Cones on unpol- linated trees on the grounds of Stanford University develop to nearly normal size, though the gametophytes do not. The megaspore membrane is usually thin and poorly organized. 500 BOTANICAL GAZETTE [JUNE It is variable in different ovules. In Agathis it is reported (3) that the megaspore membrane is thickest over the apex of the game- tophyte and gradually thins out toward the archegonia in such a way as to allow the fertilization of the lower archegonia first and to protect from the pollen tubes the later maturing upper archegonia. There does not appear to be any such difference in Araucaria, though it is usually the case that the megaspore mem- brane disappears along with the band of dead cells in the region of the archegonia (fig. 4). The time at which the pollen tubes reach the nucellus is subject to wide variations. They may do so as early as July or be deferred till late in the fall. The time at which they do so does not appear to exert any influence on the development of gametophyte or ovule, within the limits mentioned. So many tubes commonly reach and penetrate the nucellus that it is almost entirely destroyed. They usually enter through the tip, composed of large clear cells with little protoplasm, but may occasionally pass between the nucellus and integument for a very short distance before entering the former. In the cases of the large slitlike micropyles, through which the nucellus is exposed for a large part of its upper surface, the tubes ordinarily, at any rate, enter only through the tip. There do not appear to be any special peculiarities in the way the tubes pene- trate the nucellus. They go fairly straight to the region of the archegonia. Occasionally one branches; a few strike the cap of dead cells over the apex of the gametophyte and then commonly turn aside. They are surrounded by a layer of dead cells some- what like that around the female gametophyte, though it is less extensive and less regular. No indications of the breaking down of nucellar cells to make way for a pollen tube were observed unless the pollen tube was itself present to account for the effects. The nucellar cells below the tip commonly contain much starch, which largely disappears with the development of the tubes. The uniformity with which the tubes enter the tip of the nucel- lus, even when a shorter and apparently more available path is present, suggests that they are attracted by a chemotactically active secretion from the glandular tip. I did not succeed in demon- strating such a secretion. There are often considerable quantities 1914] BURLINGAME—ARAUCARIA BRASILIENSIS 501 of a slightly sticky liquid between the sporophylls, but I failed to find any evidence that it comes from the nucellar tip. At about the time the walls are formed in the peripheral parts of the gametophyte, in the latter part of February usually, the archegonium initials become recognizable. Owing to their scanty contents they are recognizable only after they are somewhat enlarged. They vary in number from about 6 to 15 or more. They are situated in a ring around the crown of the prothallus. They do not all mature at the same time, though there does not appear to be any regular order. Commonly 5-8 mature and 3 or more of these are frequently fertilized. Within the circle the indi- vidual archegonia may stand alone (fig. 4) or they may be grouped in complexes (figs. 30, 44). Each archegonium is commonly sur- rounded by an individual jacket, though in some of the complexes there may be no cells at all between some of them (fig. 44). The initial is commonly a wide U-shaped (fig. 31) or V-shaped (fig. 32) cell. It has a large nucleus and little cytoplasm. Some- times a basal cell is cut off from this cell (fig. 33) before it becomes the actual initial. The nucleus of the initial divides and a peri- clinal wall separates a thin flat primary neck cell from the inner or central cell (figs. 32, 34, 37). The central cell enlarges much more rapidly than the neck cell (figs. 38-40). The latter soon divides by an anticlinal wall. This division is more frequently in the direction of its greater diameter. Each of the halves then divides into about 6 wedge-shaped cells. The nuclei of these wedge-shaped cells are invariably at the large end of the wedge. The points of the cells meet or nearly meet at the center of the neck. At this point the cells have commonly thinner walls, less cytoplasm, and a tendency to separate and leave a free passage to the egg (fig. 46). Viewed from above, the group of neck cells has either a rounded (fig. 46) or elliptic (fig. 47) outline; from the side they usually appear as a dome or cap (fig. 45). Many variations in the form and outline of the neck occur. The size of the group as well as the number of cells in it is subject to considerable variation. The commonest arrangement is 12 cells arranged in a single tier (figs. 45, 46). Figs. 48-50 show three serial sections through a neck in which there is one extremely large cell. goa. . BOTANICAL GAZETTE [JUNE The figures also show that the cells are not all in the same plane, but are placed more or less obliquely above one another. This is not unlikely due to crowding by the large cell. Many such asym- metrical necks occur in my preparations. Occasionally one cell is so large as almost to pass for a central cell. These large neck cells possess large nuclei, as may be seen from fig. 50. Occasionally there is more than a single tier of cells in the neck; fig. 51 shows a neck of 3 tiers of cells. All the archegonial initials which I could certainly identify and. all young archegonia occur in the surface layer of cells. In one preparation there were 4 cells in a row. The outer one resembled a primary neck cell. The lowest one was large and had the general appearance of a central cell. The inner of the other two was about one-third as large as the lowest and slightly larger than the second one. An imbedded archegonium might have resulted, possibly, from such an initial as this. Though the mature archegonia are very frequently displaced and overgrown by the neighboring cells, it is ordinarily easy to find the free open passages from them to the surface. I did not find any case in which it was not very probable that such a passage exists. I am fairly convinced, therefore, that there are no deep-seated archegonia in this species of Araucaria. I believe that all such appearances are due to displacement and overgrowth. Eames has recently (3) expressed a somewhat similar opinion in regard to Agathis. I have examined a number of prepa- rations of A. imbricata and have seen no deep-seated archegonia among them. The displacement and overgrowth of the archegonia is rendered very easy Owing to the very delicate walls in the pro- thallus and to its frequently irregular outline. The more solid archegonium would thus be easily pushed into a position where the turgescent cells of the gametophyte would find an equilibrium of mutual pressures. The same fact would almost invariably lead to the crowding down into the archegonial cavity of the adjacent cells if they encountered any resistance at all in the expansion of the cavity in which the gametophyte grows. The jacket usually consists of a single layer (figs. 42, 43) of more dense cells, which are usually uninucleate and with comparatively thin walls. The wall next the egg is somewhat thicker than the 1914] BURLINGAME—ARAUCARIA BRASILIENSIS 503 others and is usually marked by a large thin spot, as is common among conifers. Occasional cells are binucleate, and sometimes the jacket is doubled in places (figs. 49, 50). In contrast to Agathis (3), the jacket is firmly united to the neck cells. In con- sequence of this the contents of the pollen tube pass through between the neck cells, in a manner to be described in another place. The growth and development of the central cell resembles that of most other conifers in its general outlines. It enlarges rapidly but remains poor in cytoplasm (figs. 37-40). At first there is a single large vacuole, later there are many small ones in the more abundant cytoplasm (figs. 41, 42). At maturity there are usually no vacuoles and the cytoplasm is very dense (fig. 43). The nucleus enlarges with the development of the central cell. At first it is placed in the upper central part (figs. 39-41). It later migrates to one side (fig. 42) and nearer the neck. From here it passes to a position just below the neck (fig. 45) as if about to divide into egg nucleus and ventral canal nucleus. I was unable to find any evidence that it does divide. No mitotic figures were seen in the developing archegonium, nor were any nuclei, other than the one, ever seen before fertilization, except in one ovule. In this case a number of small nuclei were present in the upper part of what appeared to be a mature archegonium as yet unattacked by a pollen tube. It would be rash, perhaps, to assert that such a ventral canal nucleus is never cut off, even though a persistent hunt for it has failed to reveal it. Discussion I shall not attempt at this time to discuss broadly the relation- ships of Araucaria to other members of the Coniferales, but merely to point out wherein it resembles some of them and in what ways it differs from all of them in certain features of its ovule and female gametophyte. One of the first points in which this species of Araucaria (also A. imbricata) differs from Agathis is in the length of time taken to mature seeds from the first appearance of the seed cone. From the time it can be first recognized until the seeds fall is approxi- mately 21 months. Eames (3) reports Agathis as forming the 504 BOTANICAL GAZETTE [JUNE rudiments of its seed cones nearly a year in advance of pollination, while here there intervenes scarcely any time at all. In fact, in California the greater part of the pollen is likely to be shed before there are any ovulate cones to pollinate. Observations in the native habitat might show a different state of affairs and one more nearly paralleling that of Agathis. Other conifers of course are known in which the total time is even shorter than 21 months, but I am not aware of any one in which the time is distributed in the same manner. The very considerable number of free nuclei before cell formation is another character that, taken with the very large gametophyte, reminds one of more primitive gymnosperms. Gametophytes of this size are known only among the Cycadales, Ginkgoales, and some taxads (as Torreya). A curious feature of its development is the strange absence of mitoses in the free nuclear preparations. The manner in which the free nuclear stage passes into a game- tophyte with walled cells is apparently different from that reported for any other plant. While there is a certain resemblance to the centripetal growth with ‘‘alveoli” reported for Sequoia (4) and others, yet the exact method is really quite different. The most essential feature of this difference lies in the delay of walls. If walls formed between the nuclei before the beginning of the centrip- etal movement of the inner border of the cytoplasm and were extended pari passu with it, and the nuclei divided to keep pace, there would be no very essential difference. While far too little is known about the exact methods of centripetal growth and wall- formation in any considerable number of genera to make any con- - clusions based on this feature more than tentative, it is clear that Araucaria need not be excluded from relationship either with podocarps or with abietineous conifers on this account. While there is no proof that the gametophyte invades the nucellus in Araucaria, neither is it proved that it does so in other genera where similar appearances are commonly observed. The homology of the spongy tissue and its functions is none too clear anywhere. The peculiar glandular nucellar tip is found elsewhere only among conifers of podocarpineous affinities. THompson has made the suggestion that the method of pollination found in the — 1914] BURLINGAME—ARAUCARIA BRASILIENSIS 505 araucarians is “proto-angiospermic.” It seems to me, on the con- trary, that we have been altogether too ready to accept the type of ovule which has a specialized pollen chamber securely hidden away at the base of the scale, and which can be reached by pollen only by means of special devices, as a primitive type. It is scarcely credible that the first step in the evolution of the ovule and seed should have been so complex. If, however, the gymnosperms possessing this complex type evolved a seed before a cone, as in fact there is good reason to think they did, then this might have been at Jeast one of the earlier successful types. If, on the contrary, the cone was evolved before the seed, or simultaneously with it, as it may very well have been in an apparently simple cone, what would be more natural than that the pollen should lodge in any convenient place among the scales (sporophylls perhaps) of the cone? Such an ovule would have a much better chance of survival in such a cone than if exposed on the lobe of a fernlike leaf such as those possessed by the known Cycadofilicales. I am aware that I am thus attempt- ing to introduce an apparently ancestorless conifer, but fail to see that a search for fitting ancestors is likely to be more difficult than deriving it from unsuitable ones. Imbedded archegonia have been reported (6) for Araucaria, and a comparison made with Sequoia in which somewhat similar conditions are said to be present (4). My own observations do not bear out the presence of such imbedded archegonia in Arau- caria. They are superficial in origin and become overgrown by the neighboring cells. Srvnotr has recently reported (7) practically identical conditions in the podocarps. The necks are not specially noteworthy, though they show a rather closer resemblance to those reported for Podocarpus (7) than to those of most other conifers. The failure to find a ventral canal nucleus is somewhat sur- prising in so large a gametophyte, not having advanced beyond the evolutionary stage in other respects that has been attained by conifers generally. It seems more probable that it will yet be found. Ventral nuclei have not been found as yet in one species of Torreya (2). The gametophyte, therefore, appears to be neither highly specialized nor exceptionally primitive in its structure. Its large 506 BOTANICAL GAZETTE [JUNE size and numerous and large archegonia are offset by the late devel- opment of walls and their persistent delicacy, by the apparent lack of a ventral canal cell, and by the rather specialized necks of the archegonia. Probably it presents more resemblances to the gameto- phytes of the Taxaceae and to those of the Taxodineae than to other conifers. Summary 1. The ovule possesses a very free nucellus with a glandular tip, a single integument adherent to the scale for almost its entire length, a ligule, a-_large micropyle, and spongy tissue surrounding the gametophyte. 2. There is probably a single functional megaspore, which develops into an embryo sac with about 2000 free nuclei before cell-formation. 3. Cell-formation follows on a peculiar centripetal growth of the cytoplasm and precedes wall-formation. 4. The first walls are formed on the surface of the free cells. 5. Secondary walls are formed on the spindles of the mitoses occurring in the primary cells of the peripheral regions of the gametophyte. 6. The outer cells are uninucleate, the inner ones are multi- nucleate. 7. The archegonia have single-tiered necks, usually, consisting of about 12 wedge-shaped cells. 8. The necks are on the surface of the prothallus but are often overgrown. g. The archegonia may be single or occur in complexes and have a single-layered jacket. ro. A ventral canal nucleus may be absent, STANFORD UNIVERSITY CALIFORNIA LITERATURE CITED 1. BURLINGAME, L. LANCELOT, The morphology of Araucaria brasiliensis. 1. The staminate cone and male gametophyte. Bor. Gaz. 55:97-114. pls. , 5 1914. a. Cee. J. M., and Lanp, W. J. G., The gametophytes and embryo of Tor- reya taxifolia. Bort. GAZ. 39:161-178. pls. 1-3. 1905. 1914] BURLINGAME—ARAUCARIA BRASILIENSIS 507 3- EAMEs, sf ig morphology of Agathis australis. Ann. Botany 27: ' 1-38. pls. 1-4. 4. Lawson, A. A.., The anand archegonia, ee and embryo of Sequoia sempervirens. Ann. Botany 18:1-28. —4. 1904. 5. SAxTON, W. T., Contributions to the sie sece of Actinostrobus pyrami- dalis. Ann. Botany 28:321-345. pls. 25-28. 1913 6. Sewarp, A. C., and Forp, Srp1ttE O., The Antesineias, recent and extinct. - Phil. Trans. Rov: Soc. B 198:305~411. pls. 23, 24. 1905. 7. Sinnott, Epmunp W., The morphology of the reproductive structures in the Podocarpineae. Ann. Botany 27:39-82. pls. 5-8. 1913. EXPLANATION OF PLATES XXV-XXVII Fic. 1.—Longitudinal section of a young cone in which the rudiments of the ovule are just becoming visible; 12 Fic. 2.—Longitudinal section of a stghtly older sporophyll, showing the beginnings of the oe integument, and ligule; X15. Fic. 3.—Longitudinal section through the meristem of the nucellus; X62. Fic. 4.—Longitudinal section of an ovule just before fertilization, showing the position and relative size of the gametophyte and a acta nucellus; Frc. 5.—Megaspore mother cell in synapsis; 900. Fic. 6.—Longitudinal section through an ovule in the latter part of June, showing the enlarging megaspore; 20 Fic. 7.—A megaspore just before diesen: surrounded by spongy tissue; X62. Fic. 8.—A binucleate embryo sac in late June; 62. Fic. 9.—An 8-nucleate sac in July; 62 Fic. 10.—A 64-nucleate stage in late Fol: X62. Fic. 11.—A 512-nucleate stage in late August; Fic. 12.—A small portion of the parietal prea and nuclei in late October; X 125. Fic. 13.—A whole embryo sac in October; X 20. Fic. 14.—An embryo sac in November; X 20. Fic. 15.—An embryo sac in December; - 20. Fic. 16.—An embryo sac in January; Fic. 17.—The beginning of centripetal ok of the cytoplasm; X 20. Fic. 18.—The micropylar end of the gametophyte shown in fig. 17; X 125. Fic. 19.—Centripetal growth half complete; note that some of the nuclei are how —— outward and that there are no indications of walls; X20. 20.—A detail of the same gametophyte as shown in preceding figure; Fic. 21.—The completion of centripetal growth of the cytoplasm; X62. 508 BOTANICAL GAZETTE [JUNE Fic. 22 -—Detail from micropylar end of sac of age shown in preceding figure; 125. Fic. 23.—A slightly older gametophyte; X20 Fic. 24.—A detail from preceding figure dhowins lack of walls and presence of free cells; X 250. Fic. 25.—A central part of the gametophyte in early March, showing the lack of walls; from the same slide as fig. 31; X125. Fic. 26.—Section through an ovule in which the nucellus is growing and the cavity enlarging, but in which there is no gametophyte; X 20. Fic. 27.—Section through an ovule without any gametophyte, but with its place occupied by an enlarging mass of cells probably derived from the spongy tissue; X 20. Fic. 28.—Early stage of the erosion of nucellus by the pollen tubes, July; note the abundant starch; X62. Fic. 29.—A nucellus ‘a December when most of the starch has disappeared and all the upper part of the nucellus has been destroyed by the tubes; X62. Fic. 30.—Section through an archegonial complex; note the remains of the apical cap of dead cells and the superficial neck; X85. Fic. 31.—Micropylar end of thallus about March 1, with archegonial initial; X125. Fic. 32.—Lateral portion of another thallus with young archegonium near top; X125. Fic. 33.—An archegonium initial just before division; X 250. Fic. 34.—Young archegonium just after cutting off primary neck cell; X 250. Fic. 35.—Apical end of an irregular thallus with young archegonia; Fic. 36.—Similar thallus with smooth outline and young archegonia; X62. Fic. 37.—Young archegonium; neck cell undivided; X 250. Fic. 38.—Similar archegonium with neck divided; X 250. Figs. 39, 40.—Enlarging archegonia; X 250. 1G. 41.—Archegonium about one-half mature, showing neck, vacuolate cytoplasm, jacket, and position of nucleus; X 125 Fic. 42.—Nearly mature archegonium with nucleus to one side and just below neck; 125. Fic. 43.—Mature sichegontiii, X125. Fic. 44.—Cross-section through a complex where there are no jacket cells between two of the archegonia; 125. Fic. 45.—Section showing dome-shaped neck and position of nucleus below it; 250. Fics. 46, 47.—Cross-sections through usual type of neck; X 250. Fics. 48-50.—Serial sections through neck with one very large cell; 125. Fic. 51.—Longitudinal section of 3-tiered neck; X 250. BOTANICAL GAZETTE, LVII PLATE XXV BURLINGAME on ARAUCARIA BRASILIENSIS PLATE XXVI BOTANICAL GAZETTE, LVII ILIENSIS S ARAUCARIA BRA AME on RLING BL NICAL GAZETTE, LVII PLATE XXVII ME on ARAUCARIA BRASILIENSIS THE ORIGIN OF MONOCOTYLEDONY CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 187 Joun M. CovuLTER AND W. J. G. LAND © (WITH PLATES XXVIII AND XXIX AND TWO FIGURES) The origin of Monocotyledons from the Archichlamydeae seems well enough established to need no discussion in this connection. he evidence of vascular anatomy, supported by the historical record, as well as by general morphological considerations, seems to be explicit. It remained to obtain evidence of the transition from dicotyledony to monocotyledony.. This seemed to be a peculiarly difficult situation, for it appeared to involve much more than the number of cotyledons. The difference in number was dis- posed of in two ways, the monocotyledonous condition being said to have arisen either by a fusion of the two cotyledons or by a suppression of one of them. Each of these views can be supported by a considerable body of evidence, hased upon vascular anatomy and upon many intermediate stages in fusion or in elimination. The real difficulty in the situation, however, appeared to be in the fact that in Monocotyledons the cotyledon is a terminal structure, and in Dicotyledons the cotyledons are lateral structures. How could the terminal cell of a filamentous proembryo which had been producing a stem tip change its function and persistently produce a cotyledon? Any comparison of the proembryos of Capsella and Alisma, the two accepted types of Dicotyledons and Monocoty- ledons, emphasizes this difficulty. A clue to this problem was furnished by the seedlings of Cyr- tanthus, a South African genus of Amaryllidaceae, which was investigated by Miss FARRELL,’ a graduate student of this depart- ment. In accordance with this suggestion, seeds of numerous Monocotyledons were obtained from South Africa and Australia, These were germinated and an abundance of material obtained for study. , Marcaret E., Ovary and embryo of Cyrianthus sanguineus. Bor. Gaz. $7:428-436. pl. 24. figs. 3. 1914. 509] [Botanical Gazette, vol. 57 510 BOTANICAL GAZETTE [JUNE The first case to attract our attention was that of Agapanthus umbellatus L’Hér., one of the South African Liliaceae. Although ordinarily monocotyledonous, a seedling was found with two well developed cotyledons. This discovery led us to hope that it might be used in determining the relation between monocotyledony and dicotyledony. The two conditions shown by the seedlings of Agapanthus are illustrated in fig. 1. If the seedlings of the same species are thus indifferently monocotyledonous or dicotyledonous, there must be some evident relationship between the two conditions. In the following account no attempt will be made to cite the literature of the subject. It is sufficiently well known to students of Angiosperms, and most of it is available in CoULTER and CHAM- BERLAIN’S Morphology of Angiosperms. When the remaining mate- rial that has become available is investigated, a more detailed account of the whole subject of the development of cotyledons will be given. The structure of the monocotyledonous seedling of Agapanthus, a photograph of which is reproduced in fig. 1, is shown by the series of transverse sections given in figs. 2-13, and by their diagrammatic reconstruction in fig. 14. The section through the cotyledon and first leaf above the cotyledonary sheath (fig. 2) shows three vascu-, lar strands in the cotyledon, arranged in a triangle, with the xylem directed toward the center. If the middle strand had not been laid down, the two laterals would show the inverse orientation that has suggested that the monocotyledonous condition has arisen by a fusion of two cotyledons. The cotyledon above the sheath is cylindrical, but as the sheath is approached it begins to invest the first leaf (fig. 3). Soon the sheath becomes a complete ring in transverse section, which increases in thickness around the leaf as the transition region is approached, until, at the junction with the first leaf, the investing sheath becomes of almost uniform thickness (fig. 9), that is, the side of the sheath away from the cotyledon is as thick as the side which is continuous with the coty- ledon. In all the many seedlings sectioned, the cotyledonary sheath is a simple ring in transverse section, without any infoldings. e three strands retain their positions with reference to one another until just above the transition region, where they approach 1914] COULTER & LAND—MONOCOTYLEDONY 511 one another, and their phloem strands become united (fig. 9). Farther down the three cotyledonary strands unite completely, and the phloem divides (fig. 10). The single bundle of the first leaf turns inward (figs. 9 and 10) and unites with the cotyledonary strands (fig. 11). The lateral bundles of the leaf are disregarded. embryos of A gapanthus umbella- Fic. 1.—M tyled ; and dicot tus; X4. since they appear late, and in early seedling stages are not con- nected with the main strand or with the cotyledonary plate. This union of strands, three from the cotyledon and one from the first leaf, forms a siphonostele (fig. 11), which is the “cotyledonary plate.”” The strand from the first leaf continues into the hypocotyl and becomes one of the poles of the root, and from the cotyledonary strands that enter into the structure of the cotyledonary plate, two other strands pass down the hypocotyl to form poles of the root, 512 BOTANICAL GAZETTE [JUNE which is therefore triarch. Farther down, the strand which has come from the first leaf forks, and the root becomes tetrarch. Older seedlings were not examined, but probably further forking of strands occurs, making the root eventually polyarch. In thus describing the course of the vascular strands, the sequence given seems to be that of their formation, although we did not observe the procambial strands. If this be true, they are laid down first in the growing cotyledon and first leaf, become united later in the cotyledonary plate, which then gives rise to the root poles. This means that the vascular strands do not determine the development of the structures of the seedling, but that the primordia of cotyledon and first leaf start and the vascular strands are laid down in the growing organs. In other words, growing primordia determine the vascular strands rather than the reverse. If the cotyledonary sheath is very massive, vascular bundles may be laid down, and these may have no connection with other bundles. In the cotyledonary sheath of Doryanthes Palmeri, which is very thick, a vascular strand was found at a point opposite the massive cotyledon. This solitary strand had no connection with the coty- ledonary plate, or with any other strand, beginning and ending blindly in the sheath. The inference seems evident that vascular strands are secondary structures, whose appearance is dependent upon the character of the primary structure, and or of no phylogenetic significance in the seedling. It is noteworthy also that in the seedling of Agapanthus there is no stem primordium. In fact, the stem is a very belated organ, not having appeared in the seedlings under investigation. When and how a stem primordium is organized later was not seen. Cer- tainly in the well developed seedlings of Agapanthus there is no stem primordium that gives rise to lateral leaf primordia. All of the meristematic tissue is involved in cotyledon and leaf-formation. The structure of the dicotyledonous seedling of Agapanthus shown in fig. 1 is indicated by the series of transverse sections given in figs. 15-28, and by their diagrammatic reconstruction in fig. 29. The seedling is of the same age as the monocotyledonous one. The two cotyledons are the same length, but one is slightly thicker than the other (figs. 15 and 16). The cotyledonary sheath extends 1914] COULTER & LAND—MONOCOTYLEDONY 513 farther upward on the side opposite the first leaf, giving the seed- ling a slight asymmetry (fig. 17), but soon the sheath becomes a symmetrical ring in transverse section (figs. 18 and 19). Each cotyledon has two lateral strands, as if the middle one present in the monocotyledonous seedling has not been laid down. The second leaf is also well developed, so that six strands approach the cotyledonary plate (figs. 21-23). These gradually converge, the phloem of the cotyledonary strands uniting with that of the first leaf (fig. 23), and lower down with that of the second leaf (figs. 24 and 25), but the xylem does not fuse until farther down (fig. 26). As in the monocotyledonous seedling, the cotyledonary plate is a | siphonostele, and the strand of the first leaf continues directly as one of the poles of the triarch root, and lower down divides, result- ing in a tetrarch root. - So far as the vascular strands are concerned, the two seedlings differ in the number laid down in the cotyledons. The larger single cotyledon contains three strands, while each of the smaller cotyle- dons of the dicotyledonous seedling contains two strands. The organization of the cotyledonary plate and of the root poles is the same in both cases. It is obvious that this difference in the number of vascular strands does not determine the development of one or two cotyle- dons; the number of strands is simply a result of. the development of one or two cotyledons; for vascular strands are differentiated in the tissues of a growing organ. It seems clear, therefore, that the appearance of one or two persistently growing points in the coty- ledonary region of the proembryo determines the monocotyledonous or dicotyledonous condition; and that in Agapanthus the number of such growing points is variable. In comparing the two seedlings, a suspicion might arise that the so-called dicotyledonous seedling, with its two leaves as well as its two cotyledons, is a case of the fusion of two embryos, or rather two produced by a single proembryo. This possibility has not been traced through in detail, but the vascular situation just described shows that the dicotyledonous seedling is merely a slight modification of the monocotyledonous one, and gives no Dio srg of the “fusion” of two embryos. ‘ 514 BOTANICAL GAZETTE é [JUNE It seems evident that the variability in the number of cotyle- dons could appear only in massive proembryos. The conception of monocotyledonous and dicotyledonous embryos has become a somewhat rigid one because it has been based upon such pro- embryos as those of Alisma and Capsella as types. It has become customary to regard these filamentous proembryos as primitive and typical of the two groups, and the massive proembryos that occur in both Monocotyledons and Dicotyledons as modifications. It is our belief that massive proembryos represent the primitive condition of proembryos in Angiosperms, and that only from such a proembryo could the monocotyledonous and dicotyledonous conditions have differentiated. After this differentiation, the difference has become relatively fixed by the reduction of pro- embryos to filaments. While massive proembryos occur in all the three great divisions of Angiosperms, they are notably present among the Ranales, from which the monocotyledonous branch seems to have arisen; and they are also retained by many of the Monocotyledons, notably the Arales and Liliales, and in these groups one may expect to find occasional dicotyledony or even polycotyledony. The sequence of events in the development of the embryo of Agapanthus is as follows. As the massive proembryo enlarges, the root end elongates, thus remaining narrow and pointed; while the shoot end widens, becoming relatively broad and flattish. At this broad and flat end the peripheral cells remain more actively meriste- matic than do the central cells. It is this peripheral meristematic zone that is the cotyledonary zone. In this zone two more active points or primordia appear and begin to develop. Soon the whole zone is involved in more rapid growth, resulting in a ring or tube, but with the primordia still evident. The sequence of these two stages must be kept distinctly in mind, namely, (1) the appearance of primordia, and (2) zonation. The cotyledonary zone continues its growth until a tube of considerable length is developed, leaving the apex of the proembryo depressed. In the case of the dicotyle- donous embryo of Agapanthus the two primordia on the rim of the tube continue to develop equally, the growth of the whole cotyle- donary zone being shared equally by the two cotyledons. In the 1914] COULTER & LAND—MONOCOTYLEDONY 515 case of the monocotyledonous embryos, the cells of one of the cotyledons gradually lose their meristematic activity, but those of the other one continue division, and as a result the so-called single cotyledon is developed, which is really the growth of the whole cotyledonary zone under the guidance of a single growing point. One cotyledon is not eliminated, but the whole growth is diverted into one cotyledon. Of course “tube”’ or ‘‘sheath” and ‘“cotyle- don” are all one structure, arising from the cotyledonary zone. As a result of the checked growth of one of the cotyledonary pri- mordia, there soon develops the appearance of an ‘‘open sheath” and a “‘terminal” cotyledon. The developmental stages in this case, therefore, are first two cotyledons, and then, because of one- sided growth, one large cotyledon and one so small as to be easily overlooked. ; The two primordia appearing upon the cotyledonary zone mark the places where vascular strands will be laid down. It would seem that the positions of vascular strands in such a case, therefore, are of no significance beyond indicating possibly the places where primordia have appeared, and also sometimes suggesting the num- ber of primordia; but they cannot be used even for these purposes with absolute certainty. It would be interesting to assemble the many cases of unequal cotyledons and note the variation in the checked growth of one of them, so that it ranges in appearance from a mere protuberance or ligule-like appendage, to a fairly well developed, but smaller, cotyle- don. Such a series can be observed among the so-called pseudo- Monocotyledons. In such a series it would be noted also that if the checked growth of one of the cotyledons is very early, it will contain no vascular bundles, all the cotyledonary strands being laid down in the growing cotyledon. In many cases, as in Cyrtan- thus, as growth is diverted from one cotyledon to the other, the procambium strands are also diverted toward the larger and later functioning cotyledon, and finally the strands unite. This phe- nomenon of fusing strands has been interpreted as an evidence of the fusion of cotyledons. In Fourcroya Bedinghausii, however, we found that the procambium strands of the primordium which represents a second cotyledon do not drift across and unite with the 516 BOTANICAL GAZETTE [JUNE strands of the single functioning cotyledon. In these cases, there- fore, one cotyledon is developed whether opposing strands unite or not. In monocotyledony, therefore, as shown by Agapanthus, the number of vascular strands in the single cotyledon is likely to be greater than it would have been if both cotyledons had devel- oped, for the cotyledon itself is larger. It is such cases that have suggested that monocotyledony has arisen by the suppression of one cotyledon. It is not so much the suppression of one cotyledon, as the growth of the whole cotyledonary zone to form a single cotyledon. In other words, in such a case a cotyledon is no more suppressed than are petals in Sympetalae. A further examination of the proembryos of Cyrtanthus san- guineus, reported upon by Miss FARRELL (loc. cit.), shows that in this species four primordia may appear upon the cotyledonary zone, which for a time develop equally. Then the whole zone becomes involved in the more rapid growth, giving rise to the cotyledonary ring or sheath, but with the four growing points still prominent. In the next stage the cells of the ring between a pair of growing points on each side become more active, and the four original grow- ing points begin to “grow together”’ in pairs, so that two cotyle- dons, each with two points, begin to appear. During this stage, whiclf may be called figuratively a “fusion in pairs,” the cotyle- donary sheath still continues to elongate. Later on one of the two cotyledons begins to develop faster than the other, resulting in two unequal cotyledons, which are connected at base by the thick ring. Gradually the cells of the smaller cotyledon cease dividing, and, those of the other continuing to divide, the result is a seemingly single terminal cotyledon. The developmental stages in this case are four cotyledons, two cotyledons, and finally one large cotyledon, associated with another one so small as to escape ordinary observation. The suggestion here of the possibility of polycotyledony in Cyrtanthus is plain, and the explanation of the polycotyledonous condition among certain Gymnosperms seems evident. In the current accounts of the embryogeny of Sagittaria and of other forms with filamentous proembryos, the development of the proembryo from the filamentous condition to the organization 1914] COULTER & LAND—MONOCOTYLEDONY 517 of growing points has not been traced, and the general conclusion has been reached that the terminal cell forms the single cotyledon. An examination of the stages between the filamentous proembryo and the apparently terminal cotyledon has shown that this con- clusion has been taken for granted rather than tested. It is obvious that a massive proembryo is formed before growing points appear. The terminal cell of the filamentous proembryo of Sagittaria devel- ops a mass of tissue whose meristematic peripheral cells develop a ringlike cotyledonary sheath, which in the growing seedling is still recognizable as an extremely narrow ring opposite the functional cotyledon. Just within this sheath, opposite the. functional cotyledon, is a plate of cells, one or two cells thick, occupying the site of the second coty- ledon which started as a second growing point in the cotyledonary zone. Fic. 30.—Sagittaria variabilis: transverse This plate merges with the _ section immediately above the cofyledonary base of the sheath and the ring; a, rudiments of second cotyledon (?); 150. Orv RHE first leaf, and in one in- stance was observed to extend upward 160 yw, and ended in two points (fig. 30). This vestigial structure may be interpreted vari- ously, but it seems most natural to regard it as a vestige of the second cotyledon. In Sagittaria and Alisma the “ growing point”’ of the stem has been traced to a definite plate of cells beneath the cotyledon. This plate of cells, however, is not the stem primor- ium, but the primordium of the first leaf. The “notch” so characteristic of these embryos is developed by the checked growth of a cotyledon primordium on one side of the coty- ledonary sheath, and at the base of this notch, which is really between two cotyledon primordia, the first leaf develops. The conclusion is that in both Monocotyledons and Dicoty- ledons a peripheral cotyledonary zone gives rise to two or more * + 518 BOTANICAL GAZETTE [JUNE growing points or primordia, and that this is followed by a zonal development resulting in a cotyledonary ring or sheath of varying length. If both growing points continue to develop equally, the dicotyledonous condition is reached. If one of the growing points ceases to develop, the growth of the whole cotyledonary zone is associated with that of the other growing point, and the monocoty- ledonous condition is reached. In other words, monocotyledony is not the result of the fusion of two cotyledons, or of the suppres- sion of one; but it is simply the continuation of one growing point on the cotyledonary ring, rather than a division of the growth between two growing points. In the same way polycotyledony is the appearance and continued development of more than two growing points on the cotyledonary ring. In fact, in Cyrtanthus four growing points appear at first, which under certain conditions might result in four cotyledons. The whole situation has its parallel in sympetalous corollas, in which there is zonal develop- ment associated with three, four, or five separate growing points, which, continuing development, are recognized as petals. It follows that cotyledons are always lateral structures arising from a peripheral cotyledonary zone at the top of a more or less -massive proembryo. This reduces cotyledony in general to a common basis in origin, the number of cotyledons being a secondary feature. The constancy in the number of cotyledons in a great group is no more to be wondered at than a similar constancy in the number of petals developed by the petaliferous zone. The organization of the stem tip in the seedling is worthy of consideration. In the mature seedlings of Agapanthus there is no appearance of a stem tip; all of the meristematic tissue at the tip of the proembryo is involved in the peripheral cotyledonary apparatus and the centrally placed leaves. The stem can be re- garded as existing only hypothetically in the siphonostelic cotyle- donary plate. Later in the history of the seedling the central region of the embryo beneath the leaves elongates and the stem structure begins to appear. If the early leaves of a plant are very small, an organized stem tip appears earlier in the history of the embryo, but it is doubtful whether in Monocotyledons any stem structure appears until late in the history of the seedling. In fact, BOTANICAL GAZETTE, LVII PLATE XXVIII e e 6 2 ) WIG Low aad. COULTER and LAND on AGAPANTHUS BOTANICAL GAZETTE, LVII PLATE XXIX “TEENA IYAGA : ax 8 Ee, 20 Rial fa a ey er SO Fae ala es a ai ae stig ~N ae aoe ye W3G Low ral. 0 COULTER and LAND on AGAPANTHUS 1914] COULTER & LAND—MONOCOTYLEDONY 519 the early and vigorous development of the first leaf in Monocotyle- dons is probably associated with checking the growth of the adja- cent cotyledonary primordium. Incidentally the late appearance of the stem as an organized structure probably enters into the explanation of the fact that the stem is the most advanced organ of the body in structure, as vascu- lar anatomy has indicated repeatedly. In any event, the cotyle- donary strands and first leaf strands organize the cotyledonary plate, which in turn gives rise to the root poles, and later determines the character of the stem cylinder. The main thesis of this study of cotyledony, however, is to release it from its rigid morphological categories, by showing that the cotyledonary apparatus is always the same structure, arising in the same way, and varying only in the details of its final expression. UNIVERSITY OF CHICAGO EXPLANATION OF PLATES XXVIII AND XXIX Fics. 2-14.—Monocotyledonous embryo of Agapanthus umbellatus: figs. 2-13, transverse sections beginning just above the cotyledonary sheath and ending in the cotyledonary plate (the sequence of numbers indicates the sequence of sections); fig. 14, a diagrammatic reconstruction of the sections; Fics. 15-29.—Dicotyledonous embryo of Agapanthus umbellatus: figs. 15-28, transverse sections beginning just above the cotyledonary sheath and ending in the cotyledonary plate (the sequence of numbers indicates the sequence of sections); fig. 29, a diagrammatic reconstruction of the sections; X 14. A METHOD OF CONTROLLING THE TEMPERATURE OF THE PARAFFIN BLOCK AND MICROTOME KNIFE CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 188 W. J. G. Lanp (WITH TWO FIGURES) The successful production of a continuous ribbon of paraffin depends chiefly on the temperature of the block in which the object is imbedded, and of the microtome knife. The hardness and size of the object may of course affect the ribbon, but if the object is small, not refractory, and completely infiltrated, the effect is practically negligible. If the temperature of the knife and block is made sufficiently low, very thin sections can be cut without unduly compressing the object, regardless of the melting point of the paraffin. 3 : With paraffin of a given melting point there is a definite tempera- ture at which the block and knife must be kept in order to produce a continuous ribbon of definite thickness without injurious com- pression of the sections. If the microtome is set for thinner sections without lowering the temperature of the knife and block, the sec- tions are compressed more and more as they are made thinner, until a point is reached where the tissues are crushed out of all resemblance to their original condition. This crushing of. the sections has in some instances resulted in erroneous interpretation of structures even by otherwise competent investigators. Again, if the microtome is set for thicker sections and the temperature of the knife and block is not correspondingly raised, excellent sections result, but their edges refuse to weld and they come away singly, a source of much trouble when an absolutely unbroken series is required. If the thickness is further increased, the sections come away rolled so tightly that in some instances they cannot be unrolled even by floating on warm water. In practice, when thick sections (to-20 u) are wanted, the object is imbedded in paraffin bee at 45-52°C. If thinner Botanical Gazette, vol. 57] ~ [520 1914] LAND—TEMPERATURE CONTROL 521 sections are required (3-5 uw), paraffin melting at 58-62°C. is necessary. Even when the harder paraffin is used, in order to cut sections 2-4m thick, at ordinary room temperature, the knife and block must be cooled. If they are not cooled below the room temperature, which in winter is usually about 20-22° C., the sec- tions are hopelessly crushed. In summer it becomes increasingly difhcult to make thin sections. Fic, 1.—Apparatus for temperature control, showing object holder and cooling trough in place. Many delicate plant tissues, notably certain liverworts, can be imbedded in paraffin melting at 45-52° C. with perceptibly little injury, but when the same material is imbedded at a temperature of 58-62° C. serious injury may result. For example, a tropical species of Notothylas, which at 52° showed little shrinkage, at 62° shrunk to neatly half the origina] thickness of the thallus. In addition to the action of heat, the effect of the large coefficient of expansion of paraffin (0.00027854) becomes marked when the harder paraffin is used. It follows that by using paraffin of a low melting point, the effect of heat and of the coefficient of expansion can be minimized. 522 BOTANICAL GAZETTE [JUNE In this laboratory the practice has been to cool the knife and block with lumps of ice. This method, while in the main giving good results, is unsatisfactory for the finest sectioning. Water usually gets on the ribbon and does damage; also great care is necessary to keep the microtome from rusting. The various difficulties were in a large measure overcome as Fic. 2.—Apparatus for temperature control, showing all attachments follows: The face of the ordinary circular metal object holder, which comes with all microtomes of the better class, was turned out to form a cup. A plate of thin brass was soldered over the cup, making a new face for the object holder, and turned down to the original diameter of the disk. Two holes were drilled and tapped at opposite sides of the disk and two short tubes for attaching small rubber tubes were screwed in. Fig. 1 shows this disk in the clamp of the microtome. For controlling the temperature of the knife, a trough of thin metal—tin, brass, or copper—about 20 cm. long and about 2 cm. eit Anat aie eae a gee ca gee ee pt SO ar ae 1914] LAND—TEMPERATURE CONTROL 523 deep was made to take in the knife and to permit about 1 cm. of the knife to project. A nipple at each end of the trough serves to attach small rubber tubes (fig. 1). The ends of the trough should be soldered to prevent leaking on the microtome. Any microtome knife having a detachable handle can be used. A flexible safety razor blade may be used, provided the heads of the clamping screws are flush with the sides of the blade holder. A tank provided with a stopcock and Y-tube is placed above the microtome at a height which will insure a good flow of water. One tube of the ‘“‘Y”’ is attached to a tube of the object holder by a rubber tube of small caliber, the other to the nipple of the cooling trough. Tubes lead from the holder and from the trough to a waste receptacle. The tank is filled with water of the proper tempera- ture for the required thickness of ribbon. The block and knife reach the proper temperature for cutting soon after the water is turned on. The entire apparatus is shown in fig. 2. The apparatus was designed primarily for cutting very thin sections (2-4 u) of liverworts which had to be imbedded in soft paraffin, but it has been found useful when very thick sections (20-50 u) are wanted. In cutting the latter, the knife trough is detached, and the tank filled with warm water which is allowed to flow through the object holder only. The temperature of water necessary for cutting sections of various thicknesses is easily determined by experiment. UNIVERSITY oF CHICAGO BRIEPER ARTICLES SUCCESSFUL ARTIFICIAL CULTURES OF CLITOCYBE ILLUDENS AND ARMILLARIA MELLEA (WITH THREE FIGURES) During the course of some culture work with the wood-destroying polypores in the fall of 1913, it was found of interest to try out similar methods with an agaric form. Spores were obtained from a fungus that at the time was identi fied as Clitocybe illu- dens, and from it dilution cultures were made on a beef-malt- agar medium. The spores were found to germinate readily, and in the course of three or four days numerous separate colonies ap- peared on the agar sur- face. No evidence of contamination being visible, separate colo- nies were transferred to sterile culture tubes of the same medium on November 15. Vigor- ous growth took place and the tubes soon dis- played thick felts of a brownish-white myce- lium. Early in December a small dark brown area was noticed in one of the cultures, which soon gave rise to several dark brown finger-like papillae. These continued to elongate, and lighter colored, somewhat more slender regions appeared at their tips. These now enlarged rapidly and soon Botanical Gazette, vol..57] [524 FIG. 1 1914] BRIEFER ARTICLES 525 took on the “button” form of the young fruiting agaric. On Decem- ber 26, the accompanying photograph (fig. 1) was taken, and four days later the pilei had opened to the mature condition shown in the second photograph (fig. 2). As will be seen, the fruit bodies devel- oped in a quite normal manner, and, except for their size and the somewhat “recurved” condition of the pilei, appeared to be quite normal. Fruit bodies examined with the micro- scope were seen to be sporulating profusely, and the spores were found to be quite normal as to color, shape, and size for this form. Upon being transferred to the beef-malt-agar medium, the spores germinated quite as readily as those from the original fruit bodies. Cultures are at present being maintained with the hope of obtain- ing a second fruiting tion of fruiting bodies of the second generation have been observed.' The fact that the formation of normal fruit bodies on a synthetic medium is somewhat rare led me to consider what possible conditions may have effected this result. Cultures were found to fruit in either light or darkness, and so the presence or absence of light as a factor seemed to be eliminated, although it must be said that the first stages were always initiated in the dark. All cultures from the same fruit body made on one particular lot of medium, which had been slightly Fie. 2 « Since the preparation of this article, numerous fruiting bodies of the second spore generation have been obtained, showing such striking variations in form from the origi- nal parent that it has been thought best to discuss this phase in a future paper. 526 BOTANICAL GAZETTE {JUNE scorched in preparation, either fruited or produced abortive fruit bodies, while no fruiting was observed in other cultures. The scorched condi- tion of the medium would of course give rise to substances not generally present in the culture medium, and it is suggested that this condition of nutrition may have been the determining factor. It is also of interest to note that the fruit bodies from which the spores were obtained were frozen solid when collected, which did not appear to injure the viability of the spores. Cultures of another very interesting agaric were obtained from the pathologist of the Forest Products Laboratory at Madison, Wisconsin, namely Armillaria mellea Vahl. This species forms a whitish my- celium which soon turns to a dark brown. The interesting feature, however, is the forma- tion of the so-called ‘rhizo- morphs.” These are described as appearing in nature as shining black strands often re- sembling the roots of the host. They appear soon after inocula- tion on agar cultures, ramifying throughout the substratum. Here, however, they are of a shining light gray color, and are flat and ribbon-like, often branching dichotomously (fig. 3). Upon pentrating to a free surface these rhizomorphs immediately give rise to the ordinary vegetative mycelium.—V. H. Younc, University of Wisconsin, Madison. Fic. 3 THE AMOUNT OF BARE GROUND IN SOME MOUNTAIN GRASSLANDS In July torr the writer staked out a series of 19 quadrats for study of the grassland of a mountain park at Tolland, Colorado. In that year collections were begun and censuses of some of the quadrats made. The plan was adopted of estimating at intervals the percentage composi- 1914] BRIEFER ARTICLES 527 tion of each quadrat. Early in 1912 more detailed work was undertaken, all findings being recorded on catalogue cards. Each time a quadrat was examined an e timate? was made of the percentage of bare ground. Since there seem to be no published records of such studies in our moun- tains, it has occurred to the writer that a brief note on the subject would be of interest. The mountain park under consideration is a small glaciated valley in the Rocky Mountains at an altitude of about 9000 feet. The climate is cold, the July mean being about 56° F. Most of the park has a coarse soil of decomposed granite. Upon this is a xerophytic grassland vege- tation. In certain places, however, particularly at points along the margins of creeks or ponds and in glacial sinks, a mesophytic grassland develops. This may be spoken of as “meadow.” Here the soil has a considerable amount of humus derived from washings of adjacent slopes. Of the 19 quadrats, 17 are in dry grassland and 2 in meadow The data presented (tables I and I) are arranged according to time of year. Although the observations were made in two seasons, no doubt they show normal conditions, since both years had about the usual precipitation and were not greatly different in temperatures. TABLE I PERCENTAGE OF BARE GROUND IN DRY GRASSLAND Sept. 1 omine | Mazae, | Joneses | June, | Juiyss, | Joya, | Sets | Ne Seren | 75 60 | Use ah le ere 30 36 Fate gy eee teas 60 49 oe ule 33 53 TEE ohh ce ee 63 4a Pe ea 50 46 ih ene 50 20 ee ea 13 20 —— Tuerckhei imii 41 all, J. K., work of 1 Smina Syicleny ont embryology of ¢ — _ 1 32 Smith, G. rages ope mith, , work of 544 Soil, moisture measurements 85; mo ois- ois ture and rainfall 3383 geteonnlt in 339 Solanum 155 Souéges, R., work of 168 South America, new species from 157 Spegazzini, C., work of 160 Spermatozopsis 158 Sphaerella 15 Sohensstha: 253 INDEX TO VOLUME LVII 551 Spiekermann, = work of 161 pare agi pirogyra, aa of colloidal metals on Spoehr, H. A., work of 537 we ” tirm, K.., Chemise ede der Patan ge te 2 ac . 7 work af 440 Sean ioe ert OE ‘Salal amphibious plants Sved lus N., work of 5 Sydow. and FS ak of 160 Syeabioais heron algae and sponges 342 Symphaeophyma 160 Symplocos 156 _ fe —_— of 520 Tetraclinis, tad of 255 Textile fi Thaxter, R ger Thiovulum Thismia americana 122 Thomas, H. H., work of 247, 340, 440 i crmantagg W. _ wor. 83 Thomson, R. B. 80, 82, » 87, 247, 248, 251, 337, 363: work of 8 ms iostroma 1 6 mn, A., Toes plant, plese of raves = tran- spiration assimilation o! Torrend, C., ee of 1 in fr Toxin from Rhizopus 342 Tracheid-caliber _ rer pe 287 ranseau, E. N., Transpiration, effect ok cata a Transp’ stream, and shesertien of Trees, gee of $364 of Michigan 77 Trichos rmella 1 _ G., “Ober panes Pflanzenbasen”’ Talon a Heewead of 60; ratense, — Tri vigonotarp 439, Tylode sn a new 337 U Umbelliferae, new species of 158 Urban, I., work of 160 Uromyces ; Gl ycyrrhizae 250 552 INDEX TO VOLUME LVII [JUNE 1914 V Wieland, G. R., work of 340 William se S., —s of 160, 241 Valeton, Th., work of 3 Williamsoni VanHoo k, J. M. work of 339 Wilson, E. a. an naturalist in western VanWisselingh, 6. work of 254 China” 332 Vernonieae 157 Winteromyces 160 Vicia, maturation in 531 Winton, - B. 53 Vinson, A. E. 324 Wittia 1 Viola 1 56, 159 xX Ww Xenia Xe mh winter as a factor 445 Walker, Elda, R Xylonagra 160 Water, S Sactption ‘by neon organs 255 Xylosma chloranthum 415 Watermann, H. I., of 161 : Weber van Bosse, ele work of 256, ng 342 Yamanouchi, er work of 444 Weert Born. 334 Yapp, R. HL, work of 88 iss, F. E., work of 337 Y i. Westphalian Calama € 443 oung, V. 526 White, O. E., work of 245, 439 7 Whitford, H. Wiegand, K. M.,, work of 157 Zygocactus 156 The University of Chicago Offers instruction during the Summer Quarter on the same basis as during the other oe of the MITCHELL igs sity staff w e summer by eee pa professors aa instructors from other institutions. SUMMER QUARTER, 2d Term July pian ahaa 28 Detailed Announcements will be sent upon Application The University of Chicago, Chicago, Ill. FINE INKS “™ ADHESIVES For those who KNOW Drawing Inks Eternal Tancine Higgins’ a ice Paste Vegetable Glue, Etc. aie the Finest and. wasees Inks ana Adhesives oe Ink and ill 1. 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