BOTANICAL GAZETTE THE BOTANICAL GAZETTE EDITORS: JOHN MERLE COULTER anp CHARLES REID BARNES VOLUME XLVIII JULY-DECEMBER, 1909 WITH EIGHTEEN PLATES AND ONE HUNDRED AND TWENTY-ONE FIGURES CHICAGO THE UNIVERSITY OF CHICAGO PRESS 1909 TABLE OF )F CONTENTS Variation of fungi due to environment ia thirty- seven figures) - - F. L, Stevens and J. C. Hall The development of the icin a fertiliza- tion in Juniperus communis and J geen srt vir- giniana (with plates I-IV) - Alice M. Ottley The structure of the wood in the Pineae (with sitie v) Irving W. Bailey Evolutionary tendencies among gymnosperms. Con- tributions from the Hull Botanical oo I27 - John M. Coulter On similarity in oS baat of sedis ind 1 potassium (with four figures) - - - W.J.V. Osterhout Toxic and antagonistic effects of salts as iid to ammonification by Bacillus subtilis ms five figures) Chas. B. Lipman The cuivistonbeiia of Calon (with ae VIL-IX) Lula Pace On mesarch structure in Lycopodium (with plate X) Edmund W. Sinnott Preliminary account of the ovule, gametophytes, and embryo of Widdringtonia apie deg ier: gt XI and three figures) W. T. Saxton The behavior of chromosomes in Onis lataX O. - Contributions from the Hull Botanical ry 128 (with plates XII-XIV) - Reginald Ruggles Gates The pena: of the a in sac of Smilacina stellata (with plate XV) - F. McAllister A study of pifion pine - - F. J. Phillips The embryo sac of Habenaria (with nesive inn William H. Brown The influence of traction on the formation of mechani- cal tissue in stems) - - John S. Bordner The modifiability of transpiration in young 3 seeing (with five figures) - Joseph Y. Bergen A remarkable Amanita (with ‘isha oimaat - George F. Atkinson Undescribed plants from Guatemala and die Cen- tral American republics. XXXII John Donnell Smith Some fungus parasites of algae (with seven fee George F, Atkinson Mitosis in Synchytrium (with plates XVI-XVIII)_- Robert F. Griggs Influence of oe on oa two figures) - George E. Stone Cytology of Cutleria ‘ AA PG g ft Pa Bvnyyiaty *" ees a keer ‘ “¥ ort ye - J ‘ bak ¢ 3, Neo Sigs Aiea RE ae SEE ee Pin CII ee £4 XLVUI ges ieee 9» ae . sohey Pe eae eo Ae BN Ki - piste ri . ue Re a m4 tars eg ip Sate takes ee eee te Vo 3 * arywegreret, -aNy wt ee Che Botanical Gazette A Monthly Journal Embracing all Departments of Botanical Science Edited by JoHN M. CouLTER and CHARLES R. BARNES, with the areacigs of other members of the botanical staff of the University of Chic Issued July 20, 1909 Vol. XLVIII CONTENTS FOR JULY 1909 No. 1 . VARIATION OF FUNGI DUE TO ENVIRONMENT oka THIRTY-SEVEN ee Dmg! os Stevens and J. G. Hall - - - I THE DEVELOPMENT OF THE GAMETOPHYTES AND FERTILIZATION IN [LUNIPE- RUS COMMUNIS AND JUNIPERUS VIRGINIANA Sei PLATES re Alice M. Ottl. - - - ere. THE STRUCTURE OF THE WOOD IN THE PINEAE (WITH PLATE V). Jrving W. Bailey 47 AELESER ARTICLES nh, No TES ON THE EMBRYOLOGY OF THE NYMPHAEACEAE (WITH PLATE VI). Jéel. 7. Cook 56 CURRENT LITERA ne BOOK REVIE - - - - > : - - 61 MENDELISM. THE DETERMINATION OF SEX. BIOLOGY OF CHLOROPHYLL MINOR NOTICES Be Oe ett ee ee a eee a aS POOF TEE A OM, SII TG 5 Mm a a he Bm tert Sh ES Se ie Spee gs png ee OE The Botanical eka is ete monthly, {The subscription price is $7.00 per year; the price of single “Aba is Re 5 cents. {[Postage is prepaid by the publishers on all orders from the United States, Mexico, Cuba, ohio, pa Coral Zone, Republic of Panama, tome Islands, Philippine es Guam, Tutuila a moa), Shanghai. [Postage is charged extra as follow = Canada, 35 ce pine: annual San ies (total $7. aS) on single copies, 3, os (total Ss cents) fr all other countries Postal Unio nts on annual subscriptions (total $7.84), on single copies 11 cents ig tal 86 sean: {Remittances sini be made payable to The Universite of Chi came Pi ‘aa should be in Chicago or iM es sschengn: postal or express money order. 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Lv _ confer with the editors as as aasistorss Bara wsi in any article to be offer if —_ ed, m oy ordered in prs of publication. oa -five separates of original E Separ. ates nty- | articles without covers will be s sania gratis table showing approximate cost of — ional separates _ is printed on an onlay blank wbice accompaniés ‘the proof; a copy will be sent on reques Entered August 21, 1895, at the Post-Office at Chicago, as second-class matter, under Act of pies 3» 1879. VOLUME XLVIII NUMBER 1 BOTANICAL. GAZETTE JULY s909 VARIATION OF FUNGI DUE TO ENVIRONMENT? F. L. STEVENS AND J. G. HALL (WITH THIRTY-SEVEN FIGURES) The effects of environment, climatic condition, soil fertility, the presence of unusual chemicals, the water relation, and what not, upon the form and characters of seed plants, are well known to the plant physiologist, and have been the subject of numerous studies. These factors are even utilized by the practical man to bring about desired variation. That fungi vary similarly will not be doubted any who have had to do with fungi in artificial cultures. The kind and degree of such variation, we dare say, will be a surprise to any who have not made special study of this subject. Our knowledge of the seed plants, owing to man’s long acquaint- ance with them, their larger size, and comparative stability, is con- siderable; yet even with them the limiting of genera, species, varieties, etc., presents difficulty, if we may judge from the rich literature upon phanerogamic taxonomy. ‘The fungi, because of their immense num- ber of species, variety of forms, minuteness, paucity of distinguishing characters, complexity of life-history (mostly unknown), peculiar biologic host relations (almost entirely unknown), and because of man’s short acquaintance with them and their unknown but appar- ently vast range of variability, present as yet baffling problems of rela- tionship and classification. The object of the present paper is to call attention to the kind and degree of environmental variation found in a few species of fungi that have been studied by the authors during the past four or five years, Read in part at the Baltimore meeting of the Botanical Society of America, December, 1908. I 2 BOTANICAL GAZETTE [jULy and in some instances to analyze the causes of these variations, to the end that the factor of environmental variation may be more clearly _ recognized as a problem of mycological taxonomy. We shall consider these variations under the causes that produce them. I. Density of colonies SEPTORIA PETROSELINI Des. VAR. Apit Br. & CAV., FROM CELERY This fungus, when plated so that the spores lay thinly scattered, produced colonies which were ultimately black, 1 to 2”™ in diameter, Fic. 1 Fic. 2 Fic. 1. Septoria Lycopersici Speg., sborits formation of normal pycnidia on ~ portion of thinly sown plate culture.—Fic. 2. Septoria Lycopersici Speg., showing absence of pycnidia on thinly sown portion i plate culture; magnification same as in fig. I. with pycnidia of normal character. If plated so that the spores lay in large numbers per square centimeter, it produced colonies which — reached a size of only about o.5™™ and became ultimately black, containing ordinary pycnidia, bearing spores in the normal way- _ When plated so that there were still more spores per square centimeter, the colonies never became black and no pycnidia were produced; but on the contrary, multitudes of spores were borne uncovered, in clumps — upon simple hyphae. 1909] STEVENS & HALL—VARIATION OF FUNGI 3 SEPTORIA LYCOPERSICI SPEG., FROM TOMATO Spores from pure culture were plated in 4 per cent. pea agar in various dilutions. One plate developed 5 to 6 colonies per square millimeter and each colony proceeded to normal pycnidial development. Another plate developed 21 to 23 colonies per square millimeter, and all proceeded to form naked conidia with no indication of pycnidia. Portions of these two plates are represented by photomicrographs (jigs. 1, 2). Drawings of the naked spores showing the detail of their formation are given in fig. 3. Occasionally plates with as many as 30 colonies per square millimeter were found with both pycnidia and naked spores. Pycnidia not visible at the fifth day may be well formed by the eighth day and extrude masses of pink spores about the twenty-first day. Occasionally pycnidia are well developed on the fourth day. When naked spores develop they normally appear a few days later than do pycnidia, e. g., a plate thinly sown January 12, 1907, gave many pycnidia on Jan- uary I5; while a thickly sown Fic. 3.—Mode of formation of naked plate, under conditions other: “Po under influence of crowded culture. wise precisely parallel, did not give naked spores until January 22. This Septoria forms a typical determinate colony, i. e., even with un- limited room, it proceeds only to a certain size of development. SEPTORIA CONSIMILIS E. & M., FROM LETTUCE When sown thinly, colonies reached a size of 2 to 3™™ in diameter; when sown thickly, they became no more than o.2™™ in diameter. There was no interference with color development or formation of pycnidia by thick sowing with this species. With two of these septorias, thick plating, other conditions being the same, so changed their character that not only would the species be considered as different, but the fungus would be shifted from the order Sphaeropsidales to the order Hyphomycetales (Hyplaesa of SACCARDO). 4 BOTANICAL GAZETTE [JULY A similar change of habit is well known in the genus Fusarium, which in culture, crowded or not, often abandons acervulus forma- tion, thus changing its systematic position from the Tuberculariaceae to the Mucedinaceae. The genera Colletotrichum and Gloeosporium similarly abandon acervulus formation and thus suffer still greater taxonomic disturbance by moving from the Melanconiales to the Hyphomycetales. Fic. 4.—Volutella fructi S. & H., showing colonies on thinly sown plate culture- ASCOCHYTA CHRYSANTHEMI STEVENS, FROM CHRYSANTHEMUM This fungus was plated January 12, 1907. Myriads of pycnidia were present four days later. Thick plating caused no inhibition of pycnidial formation, no naked spores, and no constant effect upon the number of pycnidia produced. VOLUTELLA FRUcTI S. & H., FROM APPLE Thinly sown, the colonies were large, of indeterminate growth, showing dark centers with pale borders (fig. 4). Thickly sow? growth was inhibited and these characters lost (fig. 5). 1909] STEVENS & HAIL—VARIATION OF FUNGI 5 SPERMOEDIA PASPALI FRIES, FROM PASPALUM? Spores of this fungus were sown January 19, 1907, in plates giving colony densities of 90, 54, 30, 14, and 1 per square millimeter. At all of these densities germination was practically 100 per cent. and growth proceeded equally in all plates during the early stages. On February 11 it was noted that all colonies which came nearly in Fic. 5.—Volutella fructi S. & H., showing effect of thick sowing. contact were sporing. Growth then stopped. In the plates bearing only one spore per square millimeter the colonies continued to enlarge slowly and to produce many spores in the central portion, though remaining white, not attaining the usual yellow color. Deep colonies appeared like the superficial, but bore no spores. On February 7 the colonies on thin plates (1 per square millimeter) had attained a 2 Later study has shown this to be the imperfect stage of an undescribed species of Claviceps, which we shall describe in a subsequent paper 6 BOTANICAL GAZETTE [yULY diameter of 1.5™™. Some of these colonies transferred to tubes con- tinued to enlarge, became tubercular, and developed a yellow center 3 or 4™™ in diameter. The whole colony often reached 1°™ in diam- eter. Sister colonies left in the plate (1 per square millimeter) failed so to develop, and it is evident that at even this density normal development is not attained. The colony is indeterminate in growth, and in plates its size is limited by the presence of adjacent colonies. SUMMARY REGARDING THE DENSITY FACTOR This factor produces different effects with the different species. It may inhibit pycnidial formation, resulting in naked spores; it may cause failure to develop color; it may limit the size of the colony; it may be without effect. There are many paired species of the imperfect fungi agreeing closely, except in the presence or absence of one character. These pairs often occur upon the same host, e. g., Seploria Lycopersici Speg. and a Cylindrosporium on the tomato; Cylindros poriumChrysanthemt E. & D. and Septoria Chrysanthemi Cav. on the cultivated chrysan- themum.3 Many other instances could be cited. The lack of fixity 3 of such a structure as even the pycnidium throws doubt upon the © validity of such species as these and indicates the necessity of close comparative study. II. Density of mycelium: zone formation The formation of concentric zones is by many fungi one of the most conspicuous characters shown in culture. These zones may be 3 VOGLINO, P., Diseases of cultivated chrysanthemums. Malpighia 15:329-341- 1902. (Exp. Sta. Rec. 14:777. : HatsteD, B. D., Chrysanthemum leaf spot. Amer. Florist 10:263. 1894. (Exp. | Sta. Rec. 6:311.) Beaca, S. A., Leaf spot of chrysanthemum. Report of Horticulturist, N. Y- Exp. Sta. Rept. 1892:557-560. Hatstep, B. D., Report of fungus disease of plants. N. J. Exp. Sta. Report 1891: 233-340. Saccarpo, Syll. Fung, 22542, m. 3497, 3498, 3757. TusBeur & Situ, Diseases of plants 478. Year Book U. S. Dept. Agr. 1906: 507. New York Agr. Expt. Sta. Rept. 14:529. New Jersey Agr. Expt. Sta. 1894: 36r. RPS es a ea goons eR ae COT aR ees ae eee 1909] STEVENS & HALL—VARIATION OF FUNGI 7 due to any one of many structural characters of the colony; to vary- ing density of spore massing, grouping of pycnidia, mycelial branching, color, etc. It is a frequent phenomenon in nature in the fairy rings of the toadstools, the concentric markings of many leaf spots, fruit rots, etc. These effects have been attributed to various causal agencies, to light relation,+ to nutrients,’ to agencies other than light, probably food, to resting periods (HEDGECOCK, /. c.), and to mycelial crowding.° ASCOCHYTA CHRYSANTHEMI STEVENS With the fungus in question the fact that the zones are not due to light or temperature relations is apparent from the fact that they do not coincide with the fluctuations of these two factors (jfig.6). In the colony shown, which is that of a plate culture kept at room tempera- ture, there was daily change from warm to cool, light to dark; yet the number of rings does not coincide with the number of these changes; moreover, zones were produced in precisely the same way on plates kept constantly in the dark as on plates kept all of the time in the light, and still the same on plates kept three days in the dark and then three days in the light. Microscopic examination shows that with this fungus the dark zone is due to a larger number of mycelial filaments, the light zone to a smaller number of threads, as is shown diagrammatically in jig. 7. It seems that with this fungus the dense crowding of the fila- ments, resulting from their repeated branching, inhibits growth either by the products of metabolism or exhaustion of nutriment. There is then a period of quiescence, followed by onward growth of a few scattered hyphae. As these outgrowing hyphae reach beyond the inhibiting influence, they branch repeatedly, until a new dense zone Motz, Emit, Ueber die Bedingungen der Entstehung der durch Sclerotinia fruc- tigena erzeugten Schwarzfaule der Aepfel. Cent. Bakt. 1 Houtcuinson, H. B., Ueber Form und Bau der Kolonieen niederer Pilze. Cent. Bakt. 1'72:602. HeEpceEcock, G. G., Zonation in artificial culture of “-egsopeein uae and other fungi. Rept. Mo. Bot. Garden 17:115-117. pls. 13-16. 1 5 MirBurn, THos., Ueber Aenderungen der Farben bei Pilzen und Bakterien. Cent. Bakt. eee 6 IstvANFFI, E, Etud I giques sur le rot gris de la vigne. Ann. aaa Gas Ampél. Roy. Hougrais 1905: 183. 8 BOTANICAL GAZETTE [JULY is formed. This process is repeated indefinitely. The rapidity of succession of zones is dependent solely upon the relation which rapidity of branching bears to rapidity of increase in length. Slow lineal 1G. 6.—A scochyta Chrysanthemi Stevens; plate culture showing that the forma- tion of zones is not coincident with diurnal changes; ink marks show growth for three consecutive days. Fic. 7.—Diagram showing, at right, the zones (stippled) and diurnal marks; at left, theoretical expression of cause of zonation 1909] STEVENS & HALL—VARIATION OF FUNGI 9 growth and much branching gives many narrow zones, rapid lineal growth with infrequent branching causes few broad zones. SCLEROTINIA LIBERTIANA FUCKEL, FROM LETTUCE Zonal sclerotial formation is exhibited by this fungus (fig. 8). That this phenomenon may be attributed to crowding of the mycelium is indicated by the fact that adjacent colonies form more sclerotia at their points of contact (jig. 9). Fic. 8.—Sclerotinia Libertiana Fuck., showing 1 f tion of sclerotia on corn- meal culture. SUMMARY REGARDING DENSITY OF MYCELIUM Zone formation in Ascochyta Chrysanthemi is due to crowding of mycelium, not to light or heat relation. A similar conclusion was reached by IstvAnFrFi® regarding the very striking zones shown by Sclerotinia. ‘The same cause may apply also with Daldinia concen- irica and many other fungi of similar structure. Io BOTANICAL GAZETTE [JULY III. Chemical relations Chemical relations have been studied with eleven fungi, the fungus being usually grown in agar with varying nutrients added. Occa- sionally other media were used. A chemical base agar (CBA) was 1G. 9.— Sclerotinia Libertiana Fuck. jcoteds the formation of sclerotia in greater abundance where adjacent colonies come in contac made of the following proportion (grams); water 1000, di-potassium phosphate 2.5, magnesium sulfate .or, calcium chlorid .or, sodium chlorid 2.5, potassium sulfate 2, agarrs. To 100°¢ of this chemical base agar were added the following materials (grams) singly or in varying combinations: ammonium lactate o. 5, sodium asparaginate 0.25, glucose 1, starch 1. The tests were usually made in both plate and tube cultures. yi ons ae ai eats elie cites i a Tg09] STEVENS & HALL—VARIATION OF FUNGI II VOLUTELLA FRUCTI S. & H., FROM APPLE This fungus, when sown thin, forms large indeterminate colonies, often with numerous scattered tubercular blotches (jig. ro). On pure agar and CBA the colonies were pale, mycelium hya- line, black tubercles very sparse. On pea agar, black tubercles were much more abundant, other- wise as on pure agar. On CBA+sodium asparaginate, black tubercles were - still more numerous. On CBA+sodium asparaginate + starch, Fic. 10.—Volutella fructi S. & H.; colony on pea agar black tubercles were showing tubercular blotches, some of them in concentric more numerous than rings; mycelium nearly hyaline, due to lack of carbo- ” in any of the above, hydrates. and the colony was black (fig. 11). On CBA-+sodium asparaginate+ glucose, black tubercles were still more numerous, so many as to be contiguous, and the whole colony was densely black. On gelatinized starch, and starch+ Uschinsky’s solution, the my- celium was black and some digestion of the starch was observed. On none of the above media were spores formed, but on sterilized apple twigs spores were produced in abundance.’ The differences here noted upon these different media are sufficient to alter entirely the general appearance and to shift the fungus from the Tuberculariaceae-Dematiae to the Tuberculariaceae-Mucedinae. CONIOTHYRIUM FUCKELII SACC., FROM APPLE This fungus when growing upon a medium rich in starch becomes black in its peripheral layer. Glucose fails to produce the same 7 N. C. Agric. Exp. Sta. Bull. 196. June, 1907. 12 BOTANICAL GAZETTE [JULY result. The mycelium is hyaline when on pea agar, but tawny on apple agar.® SEPTORIA PETROSELINI VAR. APII, FROM CELERY This fungus fails to produce naked spores when sown thickly on celery agar though it does so under similar conditions when upon lettuce agar. CoLLETOTRICHUM Carica S. & H., FROM FIG This fungus upon the different media used showed striking differ- - ences in: number of setae, varying from none to abundant; number of spores, varying from few to many; color, varying from pale to almost black. On CBA growth was scant; acervuli small, setae absent. On CBA+ammonium lactate and CBA+sodium asparaginate, growth was about as in CBA, except that numerous black setae were present. On CBA+ammonium _§lactate+ starch, the acervuli were larger, more numerous, with numerous large black setae. On CBA+sodium asparaginate+ ammonium lactate, there were a few setae. On CRA + sodium asparaginate + glucose, black setae were numerous. Fic. 11.—Volutella fructi 5, E:PICOCCUS SP., FROM APPLE AGAR IN & H.; two black colonies upon PETRI DISHES CBA + sodium asparaginate + . . and ink This fungus on pure agar CBA was colorless. On CBA+ starch or CBA + glucose, there was much richer mycelial development, which moreover took on a rich yellow color that in spots turned to 8 N. C. Agric. Exp, Sta. Bull. 196: 51. 1909] STEVENS & HALL—VARIATION OF FUNGI 13 pink. Sometimes black spots developed on the first of these media but not upon the second. This fungus shows strikingly the differ- entiating value of starch and glucose for fungus culture. Upon apple agar still another character developed, a rich golden color of the abundant, floccose, matted, aerial hyphae. This reaction is fully as striking as the familiar rose color produced by certain species of Fusarium.? With this fungus we have absence of color in agar and CBA, but rich coloring, of varying hues, in the presence of carbohydrates and upon apple agar. PHYLLOSTICTA SP., FROM APPLE AGAR IN PETRI DISHES This fungus grew faster on agar than on CBA, formed pycnidia sparsely on agar and not at all on CBA. With sodium asparaginate added the mycelium became very dense, with considerable aerial development, remained colorless, and pro- duced few pycnidia, and these visible only with the two-thirds objec- tive. The presence of glucose led to exceedingly profuse pycnidial development, while on starch the growth was as with CBA+ sodium asparaginate, showing again the ability to utilize glucose but not, starch. ALTERNARIA SP., FROM LAWSON CARNATION This fungus, the cause of an apparently undescribed carnation disease which will be the subject of a subsequent paper, was isolated during October, 1908. There were striking differences in the color of the colony upon different media, varying from merely hyaline to dense black. The size and color of the spores were also so modified as to give much more than what is usually regarded as a specific difference. On pure agar, CBA, CBA+ammonium lactate, CBA+sodium asparaginate, and upon CBA+-ammonium lactate + sodium asparagi- nate, the mycelium was colorless and the colony correspondingly colorless; while upon CBA+sodium asparaginate + starch and CBA +sodium asparaginate+ glucose, the mycelium was very dark, more profuse, more freely branched, and the colony therefore of an entirely different aspect. 9 BESSEy, ane Ueber die Bedingungen der Farbbildung bei Fusarium. Inaug. Diss. Halle. 14 THE BOTANICAL GAZETTE [JULY Spore formation proceeded sparingly, though evenly and regularly, upon pure agar, CBA, CBA+ammonium lactate, CBA+sodium asparaginate, CBA+sodium asparaginate-+ammonium lactate; but very abundantly upon CBA+ sodium asparaginate+ starch and upon CBA+sodium asparaginate+glucose. Here the sodium asparag)- nate seems not to furnish the carbon in sufficiently available form, though starch or glucose do so to nearly equal extent. The size, color, and septation of the spores were also greatly influ- enced by the medium. From carnation-agar plates the spores measured 16 to 52 # long by 6 to 13 # thick, bearing 0 to 3 longitudinal — septa and three to seven transverse septa; while from the live carnation leaf the spores were 26 to 123 # long by 10 to 20 thick, bearing 1 t09 © or often numerous longitudinal septa and 3 to 15 transverse septa. It is seen that the spores are approximately twice as long, twice as thick, of darker color, and with many more septa in each direction upon the natural medium than upon the carnation agar, differences which would ordinarily be regarded as clearly of specific rank. ALTERNARIA BRASSICAE (BERK.) SACC., FROM COLLARD This fungus made hyaline mycelium in CBA and CBA+sodium asparaginate; black mycelium in CBA-+sodium asparaginate+ glucose and in CBA+sodium asparaginate-+starch, starch producing by far the most pronounced effect. Digestion of the starch grains, somewhat in advance of the tips of the oncoming fungous threads, produced a clear zone surrounding 4 each colony in the starch-bearing plates. ASCOCHYTA CHRYSANTHEMI STEVENS This fungus was grown in the usual media with no significant effects, except that the fungus did not digest the starch grains afforded 4 in the medium. A deposit of great thickness around mycelial threads was made in the case of certain media and not in others, as has already been noted.'° In some instances culture at a high temperature occasioned this same reponse. 0 Bor. GAZETTE 44: 241. 1907. Pa ite ary 1909] STEVENS & HALL—VARIATION OF FUNGI £5 SUMMARY OF CHEMICAL RELATIONS NOTED The most striking response to chemicals is in color, which so far as observed was invariably heightened by the presence of chemicals bearing carbon in available form, the form of available carbon varying for different fungi. Some fungi, possessing ability to digest starch, can utilize this as a source, while to others the carbon of starch is inaccessible. Special unknown chemicals in apple add vivid colors to fungi otherwise hyaline. Some chemicals also promote or inhibit spore formation. Some inhibit or promote growth of setae and some even alter the size, color, and septation of spores. MILBURN,‘ working under Kiess, has also noted pronounced effects of chemicals upon the color of fungi. The difference in color effects produced by different fungi under the same conditions, and with the same fungus under different conditions, is also noted by BEssEy.? No correlation is noted between rapidity of lineal growth and nutritive value of the medium. In many instances most rapid lineal growth occurred in what was surely the poorest medium. Very poor media suffice in many cases also for spore formation, while rich media often result in cessation of spore formation. Colletotrichum Lindemuthianum, sometimes with setae, often without, has long been of questionable generic position. The same is true of several other species of this genus. Alternaria Brassicae and Macrosporium Brassicae agree closely except as to presence or absence of catenulate spores.*: Variation of this kind is probably due to variation in chemical composition of the supporting medium, e. g., change in sugar content as ripening proceeds, acting in such way as to give the fungus the appearance of belonging to one genus when upon the green sugar-tree fruit, to another genus as the starch gives place to sugar as the fruit ripens. IV. Light relation The absence of material effect of light upon lineal growth with these species of fungi is shown in Table I. Ascochyta Chrysanthemi Stevens.—The growth is more floccose in darkness. Phyllosticta sp.—This fungus forms its pycnidia in beautiful con- tt A. Brassicae “hyphis brevibus conidiis 60-80 X 14-18 4, 6-8 eo ig M. Brassicae “hyphis obsoletis conidiis 50-60 X 12-14 #, 5-11 septatis.” 16 BOTANICAL GAZETTE [you centric rings when in open room, i.e., alternate light and darkness, but in continuous darkness they were irregularly scattered. Culture — no. 35 made concentric rings when in the light, and failed to do so TABLE I E | Relation of light to growth 4 Figures express growth in millimeters. The cultures marked ‘“‘alternate’” were kept several days in light and several days in dark; L light; D dark. Inoculated Dec. 8, 1908. %@ DECEMBER LIGHT CONDITION 9 TOs) ix] eo fs | yas | as. | x65) ee ope E Tn: light Bt 1] T aa + 1 | ey ESEawaI am co PEC saeae Sa05 5050008850 0800008 Collecting the data rt ym . pt i ee 2 ‘ Pepi Hae )~=so from =the large pycnid- aaaue ee ttt ~Ssoium type i olygon saceens cot ~—s ium type in one polygon, Por H+ and = similarly with the Poe Hs small pycnidium type we | HH ann Scaceeee have: = +t SES00Sc0S8 ee saaee eee Ht S500 0000008 M= 4.1935+0.024] annus He o= 1.0902+0.0174 ausun TH fH. C. V.=25.998 +0.443 Poe Hee n= 889 HH ieststasties cot PH Corer | Poo Coe Pe rere : Coo BEE oe 2 3 6 Fic. 22.—A scochyta Chrysanthemi Stevens. Polygon of spores of large pycnidia. CI CI ‘ie H T M= 5.0379+0.09335 SeS8e6 seeee Secsueueaes T= 1.3492+0.0237 Setziee a Hy C. V.=26.781 40.593 cones seal Poor souseseaua HH pt ootH PH Co It is seen that there sana Hitt ~=is a tendency through seaee rH (| out for the smaller py& nidia to produce larger spores than are produced by the large pycnidia. i ESSE SuEauSRaUSuEEEEER a G é 6 ‘8 FIG. 23.—Ascochyta Chrysanthemi Stevens. Polygon of spores of small pycnidia. 1909] STEVENS & HALL—VARIATION OF FUNGI C. Measurements of spores from different media Pure agar. in appearance and size. M= 2.6241 +0.0313 T= 0.535410.0221 C. V.=20.402 +0.878 The pycnidia on this plate were very scant, although they were normal N=135 HERSR RBS SS PCCEEErTE Le KSEE a SRSS55 Co CoCr Tree HSQaey Coe nEEEaS Sanne +++ ceuces 2 3 4 5 6 7 Fic. 25.—Ascochyta Chrysanthemi Stevens. 0.25 percent: Polygon of spores from CB/ sodium asparaginate. ERRSS BEDeRS a ERRRER a Ao a GaEES. 2 anaeEe —-- p++ pg —+ BaBeeE Hl H 2 3 4 G. 24.—Ascochyta Chrysanthemi Stevens. Polygon of spores from e agar. CBA+0.25 per cent. dium asparaginate. SO- M= 3.5637+0.0358 = 0.7579+0.0253 CV. 25.207 (0-725 N= 204 CBA-+ sodium asparaginate +starch. M= 5.4267 +0.0355 o= 0.7896+0.0251 C. V.=14.551 40.450 N= 225 ’ Polygon | eae i--) Oe Hi 3 Fic. 26.—A scochyta Chrysanthemi Stevens. dium of ‘spores from CBA+so asparaginate + starch. 26 BOTANICAL GAZETTE [JULY eee CBA-+sodium asparagi- co rH nate+z per cent. glucose. A This was a remarkable colony with spores distinctly + ] { | i | Cor ECC smoky or olivaceous. PEE SERS RSeeeee rH FF H suas - M= 5.1422+0.0408 O intel | T= 0.9214+0.0289 3 4 ] 6 8 CV . V.=17.Q1 o: Fic. 27.—Ascochyta Chrysanthemi 7-919 £0-579 Stevens. Polygon of spores from CBA+ N= 232 sodium asparaginate + glucose. SSeeho SERRS SSSR eee SESnSuEuER BeBe . ‘ Ho Plated thickly in 4 per boo cent. pea agar. PEE a secass M= 4.3246+0.0392 PETE PEE T= 1.0138+0.0277 at SEA C. V.=23.442 +0.674 cess H paa : : mt 2 3 4 5 6 7 I 28.—Ascochyta Chrysanthemi Stevens. Polvael of spores from 4 per cent. pea agar. Cow pea agar. M= 4.8657+0.0545 g= 1.1885+0.0386 C. V.=24.427 +0.839 N= 214 : 4 5 3 Fic. 29. —Ascochyta Chrysanthemi Stevens. Polygon of spores from cow pea agar. It is seen that on these different media the mode varies materially, being low on pure agar, higher on CBA+sodium asparaginate, and still higher when glucose or starch is added. The mode is high also in natural media, such as pea agar and cow pea agar. 1909] STEVENS & HALL—VARIATION OF FUNGI 27 In the terms of the systematist, spores from pure agar measured 7.4-14.8 #, mostly 11.1.4; those from CBA+sodium asparaginate 7.4-25.9 @, mostly 12.9 b. SEPTORIA LYCOPERSICI SPEG.. OF TOMATO Suns SUSREREEREEEREE Sucneenae Coe EEEEEEEH seseiitaie co SEcGSSGeGee8 | SSSGRGSS SEER ERS Grown on apple agar. SEUGeeeane BEER M= 21.507 0.190 PEE BECEE EEE St 4 OE ESS Eee BEE C. V.=21.787+0.655 COC Coe — sageeeeee sussaaaaeee Poe SESsSeuaauus se eeeeee Sccueceeeee suaceeEe seceeaeae sins CI aces 36 Fic. 30.— Septoria gtscip Speg. Polygon of spores on apple © Grown on pure agar. _So5cn88 (AG eS os i Oe M=31.675+0.242 aut 5.879:40.17% SEESannEs C: V.==18.56020. $59 Coo n= 279 fH és ee 13 46 Fic. 31.—Septoria Lycopersici Speg. Polgyon ae: spores on pure agar. 28 BOTANICAL GAZETTE [JULY Although the number of spores measured in the two last instances is not large, the fact of a tendency to larger spores on the poorer me- dium, apple agar, is evident. The spores measured 33.6-133.2 #4, mostly 81.4 “; those on pure agar 48.1-181.3 », mostly 133.2 B. ASCOSPORES OF SCLEROTINIA LIBERTIANA FUCKEL i Trip 3 350-4 45 5 Fic. 32.—Sclerotinia Libertiana Fckl. Polygon of ascospores from middle-aged disk. Spores were secured as in the last instance, but from very young isks. M=4.0393+0.0214 T=0.37430.0151 C. V.=9.267 +0.380 n= 165 No material difference in the size of the spores here appeared with the change in age of the disks. M= 7=0.2930+0.0117 I C. V.=7.168 +0.290 N=142 Spores were discharged spon- taneously from the disk upon the cover glass, the disk being of middle age. 4.0880+0.0166 ea! Me at SD SS a A a OES RR REN a SS CECE 2. 8.4 46% Fic. 33.—Sclerotinia Libertian@ Fekl. Polygon of spores from young disk. 1909] STEVENS & HALL—VARIATION OF FUNGI 29 DIPLODIA MACROSPORA EARLE cc . . 7 — a Spores of this species, isolated from Cort corn, were grown upon pea agar. HoH M= 24.362+0.176 Coe HH Siecee i O= 3.1790+0.124 ooo = Lhd = C. V.=13.050+0.519 -2 o = N=149 - 15 30 Fic. 34. — Diplodia Poly- macrospora Earle. gon of spores isolated from corn and grown upon agar; measurements Po pea Cee showing length. FH an M= 2 e +0 5 Be Co 3-259529-43 HHH o=0.2727+0.0096 oC. V.= 8.367 409.297 x n= 183 ee ae Fic. 35.—Diplodia mac- rospora Earle. Polygon of spores isolated from corn a A SEE Coo Teer Let VOLUTELLA FRUCTI S. & H. M=8.27+0.0276 go =0.5778+0.0195 C. V.=6.986+40. 237 N= 200 Fic. 36. ey “olu- and grown upon pea agar; tella fructi S. & H. measurements showing Polygon of spores thickness showing width. H H The last five polygons are without hs 8 10 particular significance and serve only Fie. 37. Fe iit fructi h ew “ SE S. & H. Polygon of spores show- to show the variation encountere ing length. these forms. 30 BOTANICAL GAZETTE [yoy General considerations The bearing of these facts upon mycological taxonomy is apparent. If a fungus can be easily changed as regards its essential descriptive characters by a change in substratum, density of infection, or other environmental factor, these characters are worthless for descriptive purposes, unless the conditions under which they develop be accurately known. There. are two fundamental benefits from description: (1) to enable recognition of a particular form; (2) to aid in classification. The first of these is a necessary preliminary to the second, and it is with mere recognition that we have in many instances yet to deal in — mycology, particularly among the group Fungi imperfecti, with its — enormous genera, such as Septoria, Phyllosticta, and Cercospora, — with their thousands of so-called species. While life-history work and infection experiments will do much, accurate recognition of the form in hand is a necessary preliminary even to this. To reach any satisfactory basis, many fungi must be studied in — culture, under suitable standard conditions, much after the fashion that bacteria are now studied. NortH Carorina Acric. Exper. STATION AND COLLEGE WEsT RALEIGH Io ck Brads Vi tei Uh a ns etter Ree THE DEVELOPMENT OF THE GAMETOPHYTES AND FERTILIZATION IN JUNIPERUS COMMUNIS AND JUNIPERUS VIRGINIANA ALICE M. OTTLEY (WITH PLATES I—IV) INTRODUCTION AND METHODS The present paper is based upon a study of Juniperus communis and of Juniperus virginiana. J. communis was worked out more in detail, and throughout the following description it is the species referred to unless otherwise stated. Since this study was begun, two papers, SLupsky (22) and Norén (20), based on a study of J. com- munis, have appeared. In the main Norén’s observations have been confirmed by the present study. He gave a very complete history of the literature relating to Juniperus and it will not be necessary to repeat it here. The pistillate and staminate cones of J. communis were collected about one and a half miles southeast of Wellesley, Mass., those of J. virginiana from the campus of Wellesley College and near-by places. The collection of the material began the second week in March, 1905, and continued until the latter part of June of the same year. Fresh material was gathered once a week from March 13 through the first week in May; from May 8 until June 26 collections were made twice a week. The material was kept in water and put up approximately every other day. Pistillate cones of J. communis for 1903, 1904, and 1905, and of J. virginiana for 1905 were collected; the staminate cones were put up until the shedding of the pollen, which in 1905 was on May g for J. virginiana and May 11 for J. communis. The fixing agent used was Flemming’s chromacetosmic solution and the stain gentian violet and orange G. Besides the slides prepared from this material I have had the privilege of studying one hundred slides which were prepared by Miss FERGUSON in the spring of 1903. These were of great value in giving the igen dates at which to look for certain desirable stages, 31] [Botanical Gazette, vol. 48 32 BOTANICAL GAZETTE [yULY as well as in showing the variation in time of the occurrence of certain phenomena due to varying climatic conditions of different seasons. It is interesting to note that the different stages of development as worked out by Nor&n from material collected in Sweden were, in general, from three to four weeks later than corresponding stages in the material collected at Wellesley. MALE GAMETOPHYTE Both J. communis and J. virginiana are dioecious, occasionally monoecious. RENNER (21) reported the presence of hermaphrodite flowers in J. communis. I searched for similar flowers during the period of collection, but was unable to find any. The microsporangia were fully developed and the microspore mother cells were already present in J. virginiana on March 28, but in J. communis the micro- sporangia were not differentiated until April 13. The sporophylls are cyclic in arrangement and are disposed in whorls of three, with the microsporangia on the under side next to the axis of the cone (fig. 1). On April 25 the cells of the archesporial tissue were under- going their last division before the formation of the microspore mother cells. Following this division, each microsporangium consists of a central mass of polygonal microspore mother cells; surrounding these is a single layer of tapetal cells, rich in protoplasm and containing large nuclei, and a wall of two layers of cells (fig. 2), as has been described by other writers. The cells of the outer or superficial layer of the wall are large and tabular. They contain considerable resin, which causes them to stain diffusely. Very soon after the differentiation of the microspore mother cells the heterotypic division begins. Lopriore (18) reported that the microspore mother cells of Araucaria Bidwillii also undergo a very short period of rest before this division is entered upon. As soon as the walls are formed about each microspore, the mother wall breaks down, setting the spores free in the sporangium. The microspores increased in size and were shed May 11. The mature pollen grains of Juniperus do not differ as to content from 1909] ' OTTLEY—JUNIPERUS 33 more than two weeks in the time at which the pollen may be shed. The microspore in J. communis and in J. virginiana undergoes no division in the anther, and so far as I have been able to determine no prothallial cells are ever formed in them. This agrees with the condition found in J. communis (BELAJEFF 2, NOREN 20), in Biota and Cupressus (STRASBURGER 27), and in Taxus baccata, J. sphaerica, and J. chinensis (CoKER 6). In Thuja (LAND 14), Libocedrus and Chamaecyparis (LAWSON 17), a division takes place while the pollen grains are still in the anther and gives rise to the tube and antheridial cells, but in these also no prothallial cells are ever formed. The mature pollen grain has two walls, a deeply staining outer one and a faintly staining inner one (fig. 3). The outer wall of the pollen grains appears slightly roughened in many instances. When pollination takes place, the one-celled pollen grain comes to rest on the nucellar cap, the cells of which immediately lose their nuclei and become more or less disintegrated and collapsed, forming a depression in the top of the nucellus (fig. 6; Nor&n, fl. 1, fig. 5). Fifteen days after pollination the microspore divided to form the tube and the antheridial cells. The antheridial cell is the smaller of the two and remains always at one end of the pollen grain, while the tube cell is larger, possesses less dense cytoplasm, and its nucleus occupies the center of the pollen grain. Many starch grains are present at this time in the tube cell. The nucleus is large, with a loose chromatic network, and contains one nucleolus (fig. 5). As described by NoREN (20), immediately after the division to form the antheridial and the tube cells, the pollen grain germinates, and the tube pushes its way down into the tissue of the nucellus, but by June 26 it has reached only a short distance. The tube nucleus migrates into the tube, but does not reach the end of it until the following spring; whereas in J. virginiana the tube nucleus passes at once into the tip of the tube (fig. 8), and fertilization takes place in the early summer of the same year. Soon after germination in J. communis, the exine is shed in the pollen chamber and remains there, a dark-blue shell, as has been described for Taxodium by CoKER (5). In many cases the pollen grain end of the tube is raised up above the nucellar tip.into the pollen chamber, giving a peculiar appearance. This may be caused by the 34 BOTANICAL GAZETTE [JULY germination of the pollen grain before it reaches the nucellus, or it may be that the pollen tube finds difficulty in piercing the tissue of the nucellar cap, and in the effort to do so the pollen grain end is pushed up into the pollen chamber. From the appearance of the pollen tube lying in a horizontal plane on the nucellar cap before the tip enters the nucellus, it seems quite probable that the latter explanation is the more suitable one. The following spring the antheridial cell divides to form two nearly similar cells, the stalk and the generative cells. The division was not observed, but on May 8 the two cells had been formed and were seen in the pollen grain portion of the male gametophyte (figs. 9, 10). NorEN gives no figure illustrating this stage and speaks only of a stalk nucleus. The two cells soon move down the tube. At first they are very similar in appearance, but in a short time the generative cell is easily distinguished by its larger nucleus, and by the fact that it retains its own cytoplasm; while that of the stalk cell is not dis- tinguishable after passing into the tube, as in Thuja (LAND 14) (figs. 9-12). Not until after the stalk nucleus has passed the genera- tive cell does the nucleus of the latter appear larger than either the stalk or the tube nucleus (fig. 12). At this time the generative cell increases rapidly in size, and its nucleus becomes several times larger than either of the other two nuclei. The.difference in size of these nuclei is more marked in J. communis (fig. 13) than in J. virginiana (figs. 11, 12). Neither in J. communis nor in J. virginiana is it pos- sible, as stated above, to detect the cytoplasm of the stalk cell in the pollen tube. That the entire cell loses its connection with the wall of the pollen grain and starts into the tube is clearly shown in fig. 10. But very early in its downward course its cytoplasm fuses with the general cytoplasm of the tube and can no longer be distinguished from it. The end of the tube with its cytoplasmic contents advances toward the female prothallium and spreads over the upper end of the arche- gonial complex (fig. 27). The generative cell takes its position in the center of the tube near the tip, and strands of protoplasm extend from it to the lateral walls of the pollen tube and below to the tip. The stalk and the tube nuclei, which are usually of the same size and can no longer be distinguished from each other, are side by side below 1909] OTTLEY—JUNIPERUS 35 the generative cell. This corresponds with the condition at this time in Thuja as described by LAND (14). As noted by Nor&n, no starch appears in the pollen tube at this time. Previous to the division of the generative cell its cytoplasm becomes decidedly alveolar in appear- ance (jig. 13), suggesting the appearance of this cell in Zamia (WEBER 29), Cycas (IKENO 9), and Sequoia (LAWSON 15). Nor&n does not speak of this appearance, but describes the cytoplasm as coarse grained and containing a large amount of finely divided starch which might easily escape observation. I was unable to find any signs of starch in this cell at any time in its history. Just before fertilization the generative cell divides and forms two cells equal in size (jig. 27), as shown and described by Nor&n. This agrees with Biota (STRASBURGER 27), Thuja (LAND 14), Taxodium (COKER 5), and Cryptomeria and Sequoia (LAWSON 15, 16). When mature the two sperm cells in Juniperus are hemispherical in shape and lie with their flat sides face to face, but not in contact, as described by Norén, and in Thuja by Lanp (14). The division of the genera- tive cell occurs normally in Juniperus after the tube has reached the neck of the archegonium, but in one instance two similar nearly spherical cells which resembled generative cells appeared in the pollen tube when it was about half-way through the nucellus. It would seem that the two sperm cells may both be capable of functioning, as LAND (14) thinks is the case in Thuja. They are equal in size, the archegonia are borne in complexes, and the tip of the pollen tube is pressed against the neck cells of several archegonia, thus making it possible for the sperm cells from one tube to enter different archegonia. Two or three pollen tubes may reach the same archegonial complex, and there is very little branching of the tubes in their way through the nucellus. FEMALE G TE On March 28 the ovuliferous cones had appeared, but there were no indications of ovules. The first stages in their development were observed May 1. There are, as a rule, three ovules borne in the same horizontal plane at the apex of the cone. The integument arises as a little Swelling at the base of the nucellus, and by May 8 it had passed beyond the top of the nucellus. But one integument is present, and 36 BOTANICAL GAZETTE [JULY it is free to the base of the nucellus (fig. 14; Norén, l. 1, fig. 5). The arms of the integument are composed of three to five layers of cells. The micropyle is wide and deep, and no depressed pollen chamber is present until after pollination. The nucellar cap is com- posed of large clear cells, which in the upper layer project up, thus giving a jagged or irregular outline to the top of the cap. The cells beneath these are smaller, more nearly isodiametric, are arranged concentrically, and contain large darkly staining nuclei (jg. 14). Norén does not find this concentric arrangement until after pol- lination. At the time of pollination, a drop of clear liquid resembling a crystal bead is deposited on the top of each of the three ovules. It is probable that the pollen falls on this drop and is drawn down into the micropyle by the drying of the liquid, as has been described for other gymnosperms. The closing of the micropyle is brought about — by the rapid elongation of the inner row of cells of the arms of the integument. Occasionally the two arms meet in a straight line (jig. 15), as in Pinus (FERGUSON 7). More often, however, the arms dovetail together (jig. 16), also figured by Nor&n. By this method the micropyle is even more securely closed. Following the elongation of the cells cross-walls are laid down, cutting the lengthened cells into smaller ones. COoKER (5) describes a similar elongation of the innef row of cells in Taxodium, while Miss FERGUSON (7) finds it in the middle row of cells in Pinus, and Lawson (16) states that in Cryp- tomeria japonica the subepidermal and the epidermal rows both elon- gate. Norn reports that the closing of the micropyle in J. communis has recently been described by Kusart (13), but I have not seen this” paper. Soon, in the lower part of the nucellus, several faintly staining cells appear, the so-called spongy tissue of STRASBURGER. It is one of these cells that, in the following spring, is differentiated into the macro spore mother cell. It is very probable that it was the presence of this spongy tissue which led HoFrMEtsTER (8) to the opinion that the macro spore mother cell developed in early summer. Norén says that usually the macrospore mother cell could be distinguished by the beginning of July, but that occasionally two or four cells enlarge, and then it is impossible to tell which is the macrospore mother cell until the follow- 1909] OTTLEY—JUNIPERUS 37 ing spring. In my material, the macrospore mother cell in J. communis was never differentiated until the spring following pollination. Soon after pollination, May 11 for J. communis, the ovules cease to grow and remain practically the same size until the following spring (figs. 15, 16). In J. virginiana, however, the ovules continue to grow, the macrospore mother cell is differentiated, the female game- tophyte is formed, and fertilization takes place in the latter part of June or the first of July of the same year in which the ovules were pollinated. StupskKy (22) described fertilization in J. communis as taking place in the same year as pollination. Both Norg&n’s studies and the present investigation show that over a year elapses between pollination and fertilization in J. communis. It seems highly improbable that Stupsky could make a mistake in the age of the cones with which he was working, as suggested by CHAMBERLAIN (3) ina recent review in the BoTaNICAL GAZETTE. Since the present study shows conclusively that the time elapsing between pollination and fertilization in different species of Juniperus may vary by nearly a whole year it seems far more probable that SLUDSKY was working with some other species than J. communis, and that in the species with which he worked fertilization does take place in the summer following pollination, as is the case in J. virginiana. In J. communis growth began again in the early part of April. The macrospore mother cell appeared April 14 in the basal portion of the nucellus, and three days later the cell divided. In the prophase of the first division the cytoplasm is vacuolate except at one point, a short distance below the nucleus, where it is dense and stains more deeply (jig. 18), as noted by Norén. A similar densely staining mass of cytoplasm is present in all stages of division in the macrospore mother cell. No connection between this body and the division figures. could be traced. CoKER (5, 6) observed a similar condensation in Taxodium and in Thuja, but was unable to determine its significance. The presence of synapsis, the character of the spirem after synapsis, and the shape of the chromosomes indicate that this is a heterotypic division. In one slide studied there seemed to be evidence of a four- celled axial row, but from the material examined it was impossible _ to determine definitely whether the axial row consists of three or four cells. Norén states that there are three cells. 38 BOTANICAL GAZETTE [roxy The basal cell of the axial row develops into the embryo sac. Fig. 22 shows a two-celled embryo sac, with the disintegrating remains of the other cells of the axial row above it. Immediately after the first division of the macrospore nucleus, the two daughter nuclei take up a position at opposite poles of the embryo sac, and the cyto- plasm becomes more vacuolate. The cells surrounding the develop- ing prothallium are large, usually binucleate, and suggest a tapetum, as described for Taxodium by Coker (5). The nuclei of the pro- thallium divide simultaneously and form an ever-increasing ring of free cells (fig. 23). A layer of spongy tissue surrounds this ring and separates it from the other cells of the nucellus. By May 30 cell walls are laid down between the free nuclei, beginning at the periphery and extending toward the center. Contrary to SoxoLowa’s (23) generalization for gymnosperms, and Norén’s observations for J. communis, cross-walls are formed before the central vacuole has entirely disappeared. In the upper end of the prothallium a few cells do not divide by cross-walls, but remain long and narrow. These are the fundaments of the archegonia. By the latter part of May or first of June, the nuclei in these cells divide and give rise to the mother cell of the neck cells and to the central cell of the archegonium (figs. 24, 25). The central cell remains undivided until just before fertilization. Its nucleus is in the upper half of the archegonium, and below it is a large cylindrical vacuole. The cytoplasm stains faintly, and the nucleus contains several nucleoli. As a result of the division of the central cell, there arise the egg cell and the ventral canal nucleus. As observed by Norén (20) and Stupsky (22) no distinct ventral canal cell is ever formed. During the division the cytoplasm stains very deeply and presents a most peculiar appearance. Scattered throughout the entire cytoplasm are many bodies with deeply staining centers which are the so-called protein vacuoles. Three centers of radiations are present in the cytoplasm at this time, two below the large vacuole and one above it. The radiations appear to have no connection with the division of the central cell, but they are never seen so clearly at any other time as during this mitosis. Somewhat similar radiations are described by Coker (5) for Taxodium. Nor&N (19, 20) and Stupsky (22) figure and describe them for Juniperus, 1909] ; OTTLEY—JUNIPERUS 39. but cannot explain them. Fig. 26 shows these radiations in an early prophase of the division of the central cell. After the ventral canal nucleus is cut off, it moves to the micropylar end of the cytoplasm and usually disorganizes before the pollen tube bursts. Fig. 28 shows an unusually large ventral canal nucleus. The egg nucleus increases in size and moves slowly toward the central vacuole, taking up a position just above it. It usually possesses a beautiful chromatin network and a large nucleolus or several smaller nucleoli. At this time both the radiations and the protein vacuoles disappear, and many darkly staining specks appear in the egg cyto- plasm (jig. 27). Contrary to what I have observed and StupsKy (22) has reported, Nor&n (20) says that these centers of radiations, so noticeable at the time of the division of the central cell, increase in size during the maturation of the egg. There is no evidence what-. soever of this in the material which formed the basis of the present study. The archegonia form a complex which is surrounded by a layer of sheath cells. These are small and filled with deeply staining protoplasm. HormeIsTER (8) says that Juniperus frequently has archegonia in abnormal positions and Nor&én has made the same observation. The only case of archegonia in abnormal positions that was observed, is shown in fig. 36. Here the archegonium is out- side of the layer of sheath cells, but in other respects it appears normal. FERTILIZATION Fertilization follows directly upon the division of the generative cell and the maturation of the egg cell. In the summer of 1905 fertilization in J. communis occurred on June 17, 20, and 21. In ovules put up on the same day were found divisions of the central cell to form the egg cell and ventral canal nucleus, undivided genera- tive cells, sperm cells, fertilization, and proembryos. This would indicate that these divisions take place very rapidly. A mass of densely staining, coarse-grained cytoplasm accompanies the sperm nucleus on its entrance into the egg. Whether the other contents of the tube enter the archegonium was not clearly determined; in one preparation there were densely staining bodies in the upper part of the archegonium, which might be the disorganized remains of the 40 BOTANICAL GAZETTE [yoLy other nuclei. Noréw states that as a rule the two free nuclei do not enter the archegonium. The sperm cell loses its cytoplasm and passes directly to the egg nucleus. When the two nuclei have come in contact, they appear of about the same density and each contains a nucleolus and several secondary nucleoli (jig. 29). The only apparent difference is in size, the sperm nucleus being somewhat smaller. In one instance they were almost equal in size, and a dense mass of cytoplasm almost completely surrounded them. This densely staining mass is doubtless the cytoplasm of the sperm cell (fig. 30). SLtupsKy (22) describes the nucleus of the functional sperm cell as escaping from its cytoplasm and fusing with the egg nucleus, while the rest of the sperm cell forms a cap over the fusion nucleus. Whether the two sexual nuclei fuse and form one nucleus could not be determined with absolute certainty. In one preparation a nucleus was present a little below the middle of the archegonium, with a small vacuole above it and one below it. The nucleus is at rest, a chromatic network is present, and a large nucleolus (fig. 31): It seems very probable that this is a fusion nucleus on its way to the bottom of the archegonium, as this is not the position which the egg nucleus ordinarily has before fertilization, and no other nucleus was present in this archegonium. SLUDSKY (22) observed a large vacuole in the upper part of the archegonium after fertilization. He thinks this originates by the flowing together of the many small vacuoles, which he believes enter the archegonium from the pollen tube. It seems to me, however, that this vacuole is but the remains of the large vacuole present before fertilization. Nor&én (19) finds that the large central vacuole of the egg often disappears before the conjugation of the sexual nuclei. In one case there occurred what appeared to be the fusion of the ventral canal nucleus with the second sperm nucleus. Two nuclei are present in the chalazal end of this archegonium. These are unques- tionably the first two cells of the proembryo. Thus the fusing nuclei in the micropylar end of the archegonium cannot be the egg and the sperm nucleus (fig. 35). LAND (14) has reported a similar instance in Thuja and considers it a case of the fertilization of both the ventral canal nucleus and of the egg nucleus in the same archegonium. : 1909] OTTLEY—JUNIPERUS 4I PROEMBRYO AND EMBRYO I cannot confirm STRASBURGER’S (24) observation that the fusion nucleus moves to the organic apex of the archegonium before it divides. Fig. 32 shows two nuclei in the resting stage and surrounded with cytoplasm of netlike appearance, about half-way between the middle of the archegonium and its lower extremity. While the cells of the proembryo are undergoing division, the cytoplasm is alveolar and very similar to that in the generative cell just before fertilization, except that the network is slightly finer (fig. 34). Following fertilization, the three sporophylls of the pistillate cone fuse over the three ovules and form a berry-like fruit. As a rule the mature fruit contains but one or two seeds, the other ovules or ovule having ceased to grow before reaching maturity. PHYLOGENY From this study of Juniperus, it will be seen that in many respects this genus seems to be of more modern origin than many of the other gymnosperms. The cyclic arrangement of leaves and sporophylls, the absence of prothallial cells in the mature pollen grain, the absence of a ventral canal cell, and the presence of two functional sperm cells over an archegonial complex lead to this conclusion. JEFFREY (10, 11), in his investigations on the woods of the different gymno- sperms, says that the wood of Juniperus and other Cupresseae indi- cates that they belong to a family more modern than the Abieteae. And THomson (28), as a result of his study of the development of the megaspore coat and of the tapetum, concludes that “the Abieteae are the most ancient group of the Coniferales and the Taxeae the most recent, that the Taxoideae and Podocarpeae are complex, including both ancient and recent forms; and that the Cupresseae occupy an intermediate position in the phylogenetic series.”’ SUMMARY The staminate cones consist of many sporophylls, each bearing microsporangia on the under side near the axis. The pistillate cones contain three ovules, each subtended by a sporophyll. 42 BOTANICAL GAZETTE [juLy The mature pollen grain contains but one cell, no prothallial cells being present. The macrospore mother cell first appears in J. communis one year after pollination. The first mitosis taking place within it shows clearly the stages characteristic of heterotypic division. The contents of the pollen grain divide into antheridial cell and tube cell soon after pollination. In J. communis the antheridial cell remains in the pollen grain and does not divide until April of the next spring. In J. virginiana the antheridial cell divides in the early summer of the same year in which pollination takes place, and fertilization occurs - in the latter part of June or first of July. The generative cell and the stalk cell migrate immediately into the tube. The stalk nucleus passes the generative cell and lies near the tube nucleus. The generative cell does not divide until after the pollen tube has | reached the archegonia and just before fertilization. Two similar sperm cells are formed, each hemispherical in shape. The female prothallium develops, as in the other gymnosperms, by free cell formation in a hollow sphere of cytoplasm. After many — nuclei are formed, cell walls are laid down between them. These — cells grow toward the center, but before they meet, cross-walls are — z laid down. The archegonia develop from superficial cells at the micropylat : end of the prothallium. They are arranged in a group, and the entire ; complex is surrounded by a single layer of sheath cells. During the same day that the generative cell divides, and pre- sumably before its division, the central cel] of the archegonium divides. A ventral canal nucleus is formed and remains throughout its — life free in the cytoplasm of the egg, that is, no true ventral canal cell 4 is ever cut off. This nucleus remains at the tip of the egg and, as @ rule, soon disintegrates. After fertilization the first division occurs before the fusion nucleus 4 has passed to the organic apex of the archegonium. In conclusion I wish to €xpress my sincere gratitude to Professor E 1909] 7 OTTLEY—JUNIPERUS 43 Marcaret C. FERGUSON, under whose direction the present investi- gation was carried on, and to whom I am greatly indebted for sugges- tions and encouragement. WELLESLEY COLLEGE LITERATURE CITED 1. BeLayerr, W., Zur Lehre von dem eres der Gymnospermen. Ber. Deutsch. Bot. Gesells. 9: 280-287. 1 , Zur Lehre von dem ‘iat der Gymnospermen. Ber. Dentects Bot. Gesells. 11: 196-201. 1893. HAMBERLAIN, C. J., Development of Juniperus. Bor. GAZETTE 46: 237. 1908. (Abstract of 20 injra. . Crenkowsky, Zur Befruchtung des Juniperus communis. Bull. Soc. Imp. Nat. Moscou. 1853. . Coxer, W. C., On the gametophytes and embryo of Taxodium. Bot. GAZETTE 36:1-27, 114-133. 1903. , On the spores of certain Coniferae. Bor. GAZETTE 38: 206-213. ss pb on 1904. . Fercuson, M. C., Contributioris to the knowledge of the life history of Pinus. Proc. Wash. Acad. Sci. 6:1-202. 1904. . Hormetster, W., On the germination, development, and fructification of the higher Cryptogamia, and on the fructification of the Coniferae; English trans. by F. Currey, London, 1-491. - Ixeno, S., Untersuchungen iiber die fae der Geschlechtsorgane und den Vorgang der Befruchtung bei Cycas revoluta. Jahrb. Wiss. Bot. 32:557-602. 1808. Jerrrey, E. C., The comparative anatomy and phylogeny of the Coniferales. Part I. The genus Sequoia. Mem. Boston Soc. Nat. Hist. 5:441-459. 1903. , Idem. Part II. The Abietineae. 6:1-37. 1905. 12. JUEL, H. O., Ueber den Pollenschlauch von Cupressus. Flora 93:56-62. 1904. 13. Kupart, B., Die weibliche Bliite von Juniperus communis L. Sitzb. Kais. Akad. Wiss. ‘Wien, Math.-Nat. Kl. 115:1-29. 1905. 14. Lanp, = J. G., A morphological study of Thuja. Bor. GAZETTE 36: 249- I ‘0 4 S 259. 15. ia A. A., The gametophytes, Ree ss fertilization and embryo of Sequoia OREN Annals of Botany 18:1-28. 1904. , The gametophytes, inner ne embryo of Cryptomeria japonica. Annals of Botany 18: 417-444. , The gametophytes ser abe of the Cupressineae with special seierenns to Libocedrus decurrens. Annals of Botany 21:281-301. 1907. . LopriorE, G., Ueber die Vielkérnigkeit der Pollenkorner en aaa Bi Hook. Vorliufige Mitteilung. Ber. Deutsch. Bot. Gesells. 23: 335-346. 1905. - oo 44 BOTANICAL GAZETTE {jury 19. Norén, C. O., Ueber die Befruchtung bei Juniperus communis. Arkiv Bot. 3:1-11 (No. 11). 1904. 20. ———, Zur Entwicklungsgeschichte des Juniperus communis. Uppsala Universitets Arsskrift 1-64. 190 21. RENNER, O., Ueber Zwitterbliiten bei Juniperus communis. Flora 93:297- 300. 1904. 22. StupskKy, Ueber die Entwicklungsgeschichte des Juniperus communis. Ber. Deutsch. Bot. Gesells. 23: 335-346. 1905. 23. SoxoLowa, C., Naissance de l’endosperme dans le sac embryonnaire de quelques gymnospermes. Bull. Soc. Imp. Nat. Moscou. 1880. 24. STRASBURGER, E., Die Befruchtung bei den Coniferen. pp. 22. Jena. 1869. , Die Coniferen und die Gnetaceen. pp. 442. Jena. 1872. 26. —_——,, Die Angiospermen und die Gymnospermen. pp. 173. Jena. 1879. , Ueber das Verhalten des Pollens und die Befruchtungsvorgange bei den loa. Hist. Beitr. 4:1-156. 1892 : 28. Tomson, R. B. The megaspore membrane of the gymnosperms. Univ. Toronto Biol. Series 4:1-54. 1905. . WesseR, H. J., Spermatogenesis and fecundation of Zamia. U. S. Dept. Agric., Bur. Pl. Indus. Bull. 11:1-86. rgor. EXPLANATION OF PLATES I—IV The figures were drawn with the aid of an Abbé camera lucida. The degree of magnification is indicated in the description of each figure. The following abbreviations are used in connection with the figures. Antheridial cell, a; arche- gonium, arch; archesporial tissue, a.¢; central cell, c; central nucleus, ¢. 2; cy! plasmic condensation, c. ¢; egg nucleus, e. 7; generative cell, g; inner wall, 7. integument, 7; micropyle, M; microspore mother cell, Mi. m.c; microsporan- gium, Mg; microsporophyll, Mp; nucellar cap, ”. c; neck cells, nk; nucellus, #¥é; outer wall, 0. w,; pollen chamber, ?. c; oo pro; protein vacuole, p- % starch, s; secondary nucleoli, s. mu; sperm c , Sp; sperm nucleus, s. 7; Sponsy — tissue, s.t; sheath cell, sh.c; stalk cell, st. c; galk nucleus, st. n,; tapetum, tube cell, ¢. c; tube nucleus, ¢. 2; ventral canal nucleus, v. ¢. ”. vv oO PLATE I Fic. 1.—Longitudinal section of staminate cone of J. communis; April 25) — 1905. X62. Fic. 2.—Microsporangium of J. communis, showing microspore mother cells, tapetum, and wall; May 1, 1905. x 382. Fic. 3.—Mature microspore of J. communis, just before pollination. X 185% Fic. 4.—Pollen grain of J. communis, from the nucellus of an ovule, in pea phase of first division; May 26, 1905. 1850. Fic. 5.—A two-celled pollen grain of J. virginiana, two weeks after pollins = tion. 1850. Fic. 6.—Nucellar cap of J. virginiana, showing disintegration of cells beneath the pollen grain. X 116. 1909] OTTLEY—JUNIPERUS 45 Fic. 7.—Early stage in the piercing of the nucellar cap by the pollen tube of J. communis; June 3, 1905. 884. Fic. 8.—Young pollen tube of J. virginiana; June 1, 1905. X 382. Fic. 9.—Upper part of the pollen tube of J. communis, ae the stalk cell and the generative cell; May 8, 1905. 1850. Fic. 1o.—Pollen tube of J. communis, showing the tearing-away of the cyto- plasm of the stalk cell from the wall of the old pollen grain; May 10, 1905. 884. Fic. 11.—Portion of pollen tube of J. virginiana, midway through the nucel- lus, showing the generative cell with the tube and the stalk nuclei just beneath it. X 1850 PLATE II Fic. 12.—Lower portion of an older pollen tube of J. virginiana, showing the two free nuclei below the generative cell. 1850. Fic. 13.—The generative cell of J. communis, just before division; June 9, 1903. X 884 Fic. 14.—Longitudinal section of ovule of J. communis, showing nucellus and integument; spongy tissue not yet clearly differentiated; May 19, 1905. 116. Fic. 15.—Longitudinal section of ovule of J. virginiana, showing an occa- sional method of closing the micropyle. 116. Fic. 16.—Longitudinal section of ovule of J. communis in winter condition, me usual method of closing of micropyle; March 28, 1905. X 116. G. 17.—Macrospore mother cell of J. communis; April 14, 1905. 704. io. 18.—Macrospore mother cell of J. communis, in prophase of division with spongy tissue around it; April 17, 1905. 70 Fics. 19-21.—Different stages in the division of the macrospore mother cell of J. communis; April 17, 1905. 1850. Fic. 22.—Two-celled embryo sac of J. communis; May I, 1905. 704. PLATE III IG. 23.—Longitudinal section of the nucellus of J. communis, sho wing the hollow prothallium almost a year after pollination; May 5, 1905. G. 24.—Prothallium of J. communis, almost closed at the center, with arche- gonia at the micropylar end; May 30, X 62. Fic. 25.—Stages in the ieninee cit of archegonia in the same archegonial complex of J. communis; May 30, 1903. 704. Fic. 26.—Longitudinal section of archegonium of J. communis, at the time of the division of the central cell; nucleus in prophase of division; large central vacuole and prominent radiations; June 20, 1905. X 704. Fic. 27.—Longitudinal section of an archegonial complex of J. communis, with the tip of the pollen tube above it; June 20, 1905. 382. PLATE 1V Fic. 28.—Upper portion of archegonium of J. communis just before fertiliza- tion; June 20, 1905. X 1016. Fics. 29, 30.—Conjugation of sexual nuclei of J. communis, showing sheath of denser cytoplasm; June 20, 1905. X 1850, 884. 46 BOTANICAL GAZETTE [ory Fic. 31.—Fusion nucleus of J. communis between two vacuoles; June 20, — 1905. X884. q Fic. 32.—Two-celled proembryo of J. communis, surrounded by mass of 4 nutritive substance; June 9, 1903. 382. a Fic. 33.—Second division oa fertilization at base of archegonium of 4 J. communis; June 17, 1905. { . 34.—Divisions to a Pe eight-celled proembryo of J. communis; 7 aes 20, 1905. X884. : FIG. 35 SMe fertilization of the ventral canal nucleus of J. communis; June 17, 1905. : Fic. eo oe position of an archegonium of J. communis, just outside the complex; June 20, 1905. 382. r. LEP Oe J ses" rr S —_ . Coen a, bP eS SAE ae mk ‘a ye a Zl : cow OTILEY on JUNIPERUS ‘ae ite Hh 6798S! AA v ge Oy ae CS =a —_ bei einigen Peperomien. Beih. Bot. ai 23:14-26. pls. 3 908. 34 AWANO, S., Ueber die ues der Blatter. Jour. Coll. Sci. Imp. Univ. Tokyo Py bes I-49. 1909 35 SALISBURY, E. + he extrafloral nectaries of the genus Polygonum. Annals of Botany 23: oncaas: fe 16. figs. 6. 1909. 80 BOTANICAL GAZETTE [yuLy finds that there is little reason to suppose that they are of any service in protecting — the flowers from ants.—C. R. B. Centrosomes in Marchantia.3°—After a study of spermatogenesis in Mar- — chantia polymorphia, SCHA¥FNER concludes that IKENO’Ss account is correct and that centrosomes are present, both while the nucleus is at rest and while it is under- — going mitosis. His figures are practically the same as IKENO’s. MIVAKE’S — failure to find centrosomes he attributes to differences in technic.—CHartes J. CHAMBERLAIN. E Thermotropism.—Pout3’ describes observations and experiments that he é has made upon the cultivated flax, which show its great sensitiveness to radiant — heat, the young shoots directing themselves toward the source. Experiments also 4 show that heat is the dominant factor in inclination of the shoots, which is often — ascribed to light —C.'R. B. Discomycetes.—Miss BACHMAN has publisheds* a descriptive catalogue of the Discomycetes within five miles of Oxford, O. Keys to genera and species are provided, and there are illustrations of ten of the sixty-odd species, a goodly % number of which are now for the first time reported from southwestern Ohio.— ce. 5: Light and respiration. —Lowscuin reports that when he excluded the effects Z of actinic warming he was unable, in tl ; the respiration of certain fungi (Aspergillus, Penicillium, sporium), to detect any regular acceleration of it by light —C. R. B. 3° SCHAFFNER, JoHN H., The centrosomes of Marchantia polymorphia. Ohio” Naturalist 9: 383-388. pl. 27. 1908. 37 Pohl, J., Der Thermot ropismus der Leinpflanze. Beih. Bot. Centralbl. 24:11- 131. figs. 6. 1908. 38 BACHMAN, FREDA M., Discomycetes in the vicinity of Oxford, Ohio. Pr Ohio State Acad. Sci. 519-70. pls. 4. 1909 _ _% Lowscuin, A., Zur Frage iiber den Einfluss des Lichtes auf die Atmung niederen Pilze. Beih. Bot. Centralbl. 23: 54-64. 1908. 4 . XLVIII No. 2 BOTANICAL GAZETTE August I909 CONTENTS Evolution i Gymnosperms ary Tendencies among Gymnosp Jain I; Coulter On Similarity in the Behavior of Sodium and singer W. J. V. Osterhout Toxic and Antagonistic Effects of Salts as Related to Ammonification by Bacillus subtilis Chas. B. Lipman The Gametophytes of Calopogon * ‘Lula Pace On Mesarch Structure in Lycopodium _ Edmund W. Sinnott Briefer Articles a Some Hitherto Undescribed Plants from Oregon J. 9 mae Be ae Current Literature The University of Chicago Press CHICAGO and NEW YORE. i eg teed Wesley and ‘son, a ew The Botanical Gazette A Monthly Fournal Embracing all Departments of Botanical Science ited by JoHN M. CouLTeR and CuHaRLes R. BARNES, with the sone of other members of the botanical staff of the University of Chic Issued August 21, 1909 ol. XLVI CONTENTS FOR AUGUST 1909 No. 2 VOLUTIONARY TENDENCIES AMONG GYMNOSPERMS. CoNTRIBUTIONS FROM THE HULL BoranicaL LABORATORY 127. /John M. Coulter - 81 NY SIMILARITY IN THE BEHAVIOR OF SODIUM AND POTASSIUM ne FOUR FIG- URES). W.J.V. Osterhout - 98 OXIC AND ANTAGONISTIC EFFECTS OF SALTS AS RELATED TO AMMONIFICA- TION BY BACILLUS SUBTILIS (WITH FIVE FIGURES). Chas. B. Lipman - 105 B E GAMETOPHYTES OF CALOPOGON (wirH PLATES vu-Ix). Zula Pace - - 126 N MESARCH STRUCTURE IN LYCOPODIUM (witn pLate x). Edmund W. Sinnott - 138 RIEFER ARTICLES Some HITHERTO UNDESCRIBED PLANTS FROM OREGON. jf. i. poetics - : - 146 IRRENT LITERATURE BOOK REVIEWS 2 is . sd ss ¥ i * < - - > - 149 ECOLOGY OF PLANTS. EXPERIMENTAL MORPHOLOGY. THE VEGETATION OF SWITZER- LAND ; MINOR NOTICES Serer oie 2 uk E f E é = - - - 154 NOTES FOR STUDENTS - a ‘ 2 2 ? : z : - - - wi LOZ The Botanical Gazette is published month! 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Sod Aig sate Foor Cohen se ninek tet SE Tee. VOLUME XLVIII ‘NUMBER 2 BOTANICAL GAZEPTe AUGUST 7909 EVOLUTIONARY TENDENCIES AMONG GYMNOSPERMS CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 127 JoHN M. COULTER The investigation of gymnosperms has proceeded with such vigor that some adequate picture of the group freed from its details may now be obtained. The confusion of details often obscures the impor- tant facts, and it may be of service, at this stage of our knowledge, to emphasize them. There is no better way in which to develop a clear picture of a great group than to select those facts of structure that enter into its general evolutionary history. This has nothing to do with differences among species, or even among genera, which may be left to the taxonomist; but it deals with those general tendencies to change structures which can be noted in passing from the most ancient gymnosperms to the most recent. ; While the discovery of these tendencies aids in reaching conclusions _ in reference to the phylogenetic connections of the groups of gymno- sperms, it must be remembered that the tendencies are facts and the phylogenetic conclusions are very uncertain inferences. Moreover, _ a general tendency expresses itself throughout a great group, and has _ to do with the transition from ancient to modern forms, rather than _ with the breaking-up of the group into several phylogenetic lines. _ Failure to remember this fact has been responsible for much sterile _ inference as to relationships, similar stages in some general tendency _ being assumed to mean immediate genetic connection. The organ- _ ism is a plexus of structures, and must be considered in its totality _ when relationships are being considered. Among the general tend- _ encies leading to the origin of seed plants, for example, that which _ Tesulted in heterospory must be regarded as of paramount importance, 81 82 BOTANICAL GAZETTE ' - [aveust | and yet it is clear that heterospory arose several times, and probably — many times, independently as the natural result of a general tendency — among pteridophytes. To put into the same genetic group all heterosporous pteridophytés would be regarded now as a morpho- . logical absurdity; and yet there have been repeated suggestions of relationship, especially among conifers, on the basis of certain features — of the female gametophyte, for example, features which represent a 7 Stage in a general change that may occur in a number of independent 3 lines. a In passing from the ancient to the modern gymnosperms, it becomes — evident that groups differ as to the rapidity with which they respond — to a general tendency to change, and it, is this difference that helps to constitute groups. A modern group, for example, may associate a : number of ancient features with others that are recent; or all of the — ancient features may have been changed. This has been called the “lagging behind” of certain structures, but it should not imply that — they are held back and will comé forward later ; it simply means that — for some reason they have not responded to the general tendency 4 among gymnosperms to change ina certain direction. The reten- tion of an old structure must not be confused with the reappearance 4 ofan old structure. For example, it seems clear that the most ancient gymnosperms were large-leaved forms, from which the small-leaved conifers were derived; and yet small-leaved pteridophytes were — probably more ancient than large-leaved ones. If this be true, the appearance of small leaves among conifers is the reappearance of an ancient feature, and not its retention. To prove the retention — of an ancient feature demands the establishment of its phylogenetic continuity. E PHYLOGENY | d Before sketching the general evolutionary tendencies among gymnosperms, it will be of service to outline what seems to be i from citations. Those who know the facts and the investigators dog not need their recital; and those who do not know them would only . be confused by their recital. 4 Igo9] COULTER—EVOLUTION AMONG GYMNOSPERMS 83 The Paleozoic groups Cycadofilicales' and Cordaitales represent the historical background of gymnosperms. They are of equal age, so far as the records are available, and are’so connected by inter- grading (or rather anastomosing) forms that their relationship seems evident. The Cycadofilicales are so fern-like in every feature except their seeds, that their derivation from some ancient fern stock (called provisionally Primofilices) is as certain as phylogenetic con- nections can be. The origin of the Cordaitales, therefore, presents two alternatives: either they arose independently from the same ancient fern stock, or they were differentiated from the Cycadofilicales very early. To choose between these alternatives is not very impor- tant, but the latter one seems to be the more reasonable, because the Cordaitales (as we know them) are much more removed from the ferns than are the Cycadofilicales. If this conclusion is accepted, it follows that gymnosperms began with Cycadofilicales more ancient than any yet known; that Cordaitales branched off from Cycado- filicales earlier than our present records; and that the two groups constituted the extensive gymnosperm flora of the Carboniferous. This Paleozoic display of gymnosperms was succeeded by a Mesozoic display, in which at least four groups are recognized. From the Cycadofilicales there arose the Mesozoic Bennettitales and the Cycadales; and from the Cordaitales the Mesozoic Ginkgoales and Coniferales were derived. The Bennettitales have been traced almost to the Paleozoic, and their structure, as well as the habit of some of the earlier forms, make their connection with the Cycadofilicales appear convincing. The relation of the Bennettitales to the Cyca- dales is not so clear; either the two groups were differentiated from # common stock that arose from the Cycadofilicales and continued Into the Mesozoic, or the Cycadales were differentiated early from the Bennettitales. The records show that the Cycadales are much younger 84 BOTANICAL GAZETTE [AUGUST i than the Bennettitales, and were much more scantily represented dur- — ing the Mesozoic; and therefore the latter alternative seems to be the — more reasonable. In any event, the only question at issue is whether — the gymnosperm stock which came from the Cycadofilicales into the Mesozoic is to be called Bennettitales or a Bennettitales-Cycadales — plexus (a “common stock”); and it is altogether probable that this : stock has already been assigned to the Bennettitales in the description | of cycadophyte forms from the Triassic and Jurassic. In the gymnosperm flora of today, therefore, the Cycadales, although — relatively a modern group, are the nearest representatives of the : Paleozoic Cycadofilicales. E The Ginkgoales and Coniferales have both been traced into late and independent Paleozoic connection with the Cordaitales, and were — well displayed during the Mesozoic. The Ginkgoales, while widely distributed during the Mesozoic, apparently were never a large — group; and this group has continued as a single line into the present — flora, and has retained certain features of the Cordaitales which the : Coniferales have lost. The Coniferales, on the other hand, began — that extensive differentiation during the Mesozoic which has resulted in six recognized tribes in our present flora. Among these tribes the — earliest to be recognized are the Abietineae and the Araucarineaés and their very early separation is so evident as to raise the question — whether they may not be independent in origin. In any event, the : other tribes recognized in our present flora were of later origin; the : Taxodineae and the Cupressineae, and possibly the Taxineae, arising — from the Mesozoic Abietineae; and the Podocarpineae possibly arising from the Mesozoic Araucarineae. : The connections of the Gnetales are altogether obscure, and : every opinion as to their origin must be regarded as very tentative. : Although they have not been discovered as fossils, the great amount — of differentiation they show and their widely scattered geographical : distribution indicate a considerable history. Evidence seems to © accumulating that they may have been derived from the Cupressinea® — or at least that they are closely related to that tribe in origin. - VASCULAR ANATOMY S ve The central cylinder of the Cycadofilicales, like that of ferns, was protostelic, siphonostelic, or polystelic. Whatever may be “ RE 1909] COULTER—EVOLUTION AMONG GYMNOSPERMS 85 genetic connection of these types of cylinder, the siphonostele is the type that was carried forward in the evolution of gymnosperms. This siphonostele was made up of collateral mesarch bundles, developed secondary wood composed of tracheids, and the bundles of all its peripheral connections were concentric or at least mesarch. Among the gymnosperms the universal tendency was to eliminate the centripetal xylem, a tendency carried forward from the ferns, until the collateral mesarch bundles of the central cylinder became collateral endarch; and more gradually the bundles of the peripheral regions became collateral mesarch and finally collateral endarch. So early was this accomplished for the central cylinder that a collateral endarch cylinder is a feature of gymnosperms in general. From what has been said as to the variable rate of change among the mem- bers of a great group, it would be expected that mesarch and even concentric bundles might be found in peripheral parts of certain species of genera whose allies had completely eliminated centripetal xylem, or might occur occasionally in any species or genus. It is an interesting fact that centripetal xylem appears to linger longest in the cotyledons; and the number of gymnosperms in which it is own to occur in this organ, regularly or occasionally, is increasing rapidly. ; In the development of secondary wood, the general tendency among gymnosperms is to increase it in amount, so that a thick vascular cylinder is built up by the primary cambium. This tend- ency is apparent among the Cordaitales, but it reaches its most con- spicuous result in the Coniferales and Ginkgoales. This changed also the general topography of the stem, both pith and cortex being much reduced in relative amount. The Bennettitales and Cycadales responded feebly if at all to this tendency, one of their features being the retention of the general stem structure of the Cycadofilicales. In these groups the primary cambium is either short-lived or functions very slowly, and in some forms secondary cambium produces cortical bundles; but the formation of secondary wood never prevents the formation of a large pith and an extensive cortex. It is in these Sroups also that the concentric and mesarch bundles are most com- mon in the peripheral members, being found somewhere in all forms; while among the Coniferales the centripetal xylem has been - 86 BOTANICAL GAZETTE [aucusT | almost completely eliminated. In vascular anatomy therefore, the 4 Cycadales have retained more ancient features than any other liv-_ ing group. The vascular condition among Gnetales can hardly be spoken of 4 in connection with general tendencies; but the appearance of true 4 vessels associated with the tracheids of the secondary wood is too | important to omit. In any event, these true vessels of the secondarill 3 wood suggest that in the evolution of the vascular cylinder the original - tracheids of secondary wood are finally and gradually replaced by true vessels. ia sperms possessed ample, fern-like leaves, and under appropriate z conditions this type of leaf persisted, as in the tropical cycads of — today. The conifers, however, have developed a very different — type of leaf, one that was well under way among the Cordaitales, and 3 which reaches an extreme expression in small and rigid needles or concrescent scales. This cannot be regarded as the result of a general tendency among gymnosperms, quite unrelated to conditions ‘ of living, such as is shown by the persistent progressive changes of 3 other structures. The leaf is too variable a structure, and too closely E related in its work to external conditions to permit such a an explana-_ tion of its changes. 4 It would be interesting to know the conditions in which needles and concrescent disks were established; but in the absence of any such knowledge, the sharply contrasted geographical distribution of Cycadales and Coniferales may suggest that the conditions of chan were associated with the evolution of the land areas and of the climate of the temperate regions. THE STROBILUS The Cycadofilicales are the only gymnosperms ca. strobili. Although the sporophylls differ more or less from the fern-like ” foliage leaves or their branches, they are not aggregated into a strobilus distinct from the rest of the shoot. The organization of a strobilus i Wate es Sheed Tote Oe Rae Poe 1909] COULTER—EVOLUTION AMONG GYMNOSPERMS 87 by the shortening of the sporophyll-bearing shoot is a conspicuous feature of gymnosperms, and it must have been derived from the condition observed among the Cycadofilicales. The Cordaitales were the first gymnosperms to produce strobili, and this is one of their conspicuous contrasts with Cycadofilicales. The record of the structure of their strobili is meager, but it shows several tendencies in strobilus-formation. Of primary importance is the fact that the strobili are monosporangiate, and this monospo- rangiate character prevails throughout the Ginkgoales and Coniferales. Among the Gnetales, a group probably related to the general conifer- ophyte phylum, amphisporangiate strobili occur in Tumboa. If this connection be accepted, therefore, these amphisporangiate strobili have been derived from monosporangiate strobili. It is not necessary to associate in one genetic connection all of the amphispo- rangiate gymnosperms, for that condition doubtless appeared inde- pendently several times, just as the monosporangiate strobilus is known to have appeared at least twice in distinct phyla (Cordaitales and Cycadophytes). Another fact in reference to the strobili of Cordaitales, which must stand for the most ancient gymnosperm strobili, is that they included both simple and compound strobili. The staminate strobilus was simple, that is, its sporophylls were borne directly upon the axis of the strobilus; and this type of staminate strobilus persisted through- out the Ginkgoales and Coniferales. Among the Gnetales the staminate strobilus is compound, the individual simple strobilus being borne on axes of the second order in the axils of sterile bracts which make up the general strobilus. There is an evident relation-~ ship between the compact compound staminate strobilus, such as occurs in Ephedra and in Tumboa, and the short foliage branch bearing axillary simple staminate strobili, as in Torreya. ‘Even in Gnetum the compound staminate strobilus is a loose one; and among the taxads there is a tendency to compact the staminate strobiliferous branch. The conclusion is that the staminate strobilus among coni- ferophytes is quite persistently simple, but that in the more modern members of the phylum it tends to become compound, a condition accomplished by compacting a short strobiliferous shoot. The ovulate strobilus of Cordaitales was compound, at least in 88 BOTANICAL GAZETTE [AUGUST the very few specimens sectioned; that is, the ovules were borne on short secondary and bractlet-bearing axes that arose in the axils of the sterile and overlapping bracts that constituted the strobilus. This compound ovulate strobilus is a distinctive feature of the coni- ferophytes, prevailing among the Pinaceae and characterizing the Gnetales. That simple ovulate strobili may have been derived from it is quite possible. For example, in Torreya the ovulate strobili are simple and are axillary on short leafy branches, just such a branch as could have arisen through the elongation of the axis of a compound ovulate strobilus, so that the sterile bracts could be replaced by foliage leaves. It may be said that the change may have taken place in the other direction, and that the short leafy strobiliferous branch was compacted into a compound ovulate strobilus; but it must be remembered that the Cordaitales with their compound ovulate strobili are very old, and that the Taxineae with their leafy strobilif- erous branches are relatively very recent. Of course it may be discovered that the Cordaitales included also forms with simple strobili on leafy shoots. This possibility is further emphasized by the fact that the ovulate strobili of the Araucarineae, and of their allies the Podocarpineae, are simple. The former tribe is a very old one, and its connection with the Cordaitales is either direct of nearly so, so that it is altogether probable that such ovulate stro- bili occurred in that group. The connection of the Taxineae with the Cordaitales, however, appears to be so remote, and their relation to groups with compound ovulate strobili seems to be so much more immediate, that it is more reasonable to suppose that their ovulate strobiliferous branches have arisen from compound strobili in the way described above. Long after the Cordaitales had established their simple staminate and compound ovulate strobili, strobili appeared in the cycadophyté phylum, being found in Bennettitales and Cycadales; and even in the living Cycas the loose ovulate strobilus retains the evidence of its origin from the separated sporophylls of Cycadofilicales. The cycat ophyte strobilus has always been simple, and this may be related to the more compact habit of body, with its lack of free-branching: The most remarkable feature of the early strobili of this phylum however, is their amphisporangiate character, the two sets of spot . 1909| COULTER—EVOLUTION AMONG GYMNOSPERMS 89 phylls holding the same relation to one another that is held by the stamens and carpels of angiosperms; and this marks the Bennettitales as a unique group among gymnosperms. The monosporangiate tendency, however, which characterizes the coniferophytes, is shown by the Cycadales among cycadophytes, and it was either established directly, or it arose from an early differentiation of the amphispo- rangiate strobilus of the Bennettitales. The evidence of history favors the latter view, but the probabilities of the situation favor the former. In any event, both monosporangiate and amphisporangiate strobili were established among cycadophytes. THE STAMEN Among gymnosperms the stamen may be regarded as a very con- servative structure, retaining throughout most of the phyla its fern- like characteristics. Its form perhaps became almost as much differentiated among the Cycadofilicales as it ever became among gymnosperms. In this primitive group, in addition to microsporo- phylls resembling fern-like leaves with abaxial synangia, there appeared others that have been spoken of as the Crossotheca (“epaulet”) and the Calymmatotheca (“cupule”) types, and in all probability still others will be discovered. All of these types were continued among the coniferophytes, with varying details of minor importance. Among some of the Gnetales, either the sporophyll has become very much reduced, or it has become suppressed, so that the microsporangia are cauline; but even in Tumboa the old terminal synangium is evident. Among the cycadophytes, on the other hand, only what may be regarded as the most ancient type of microsporophyll has been retained, that is, the fern-type with abaxial sporangia (often syn- angia). Among the Bennettitales, there is so little departure from the old type that their microsporophylls resemble pinnate fern leaves with abaxial synangia; and even among the Cycadales the more or less leaf-like microsporophylls show the same character. If there is any tendency in the stamens of this phylum worth noting, it is the tendency shown among the cycads to reduce the sterile apex of the sporophyll to a more compact peltate expansion. The microsporangium of gymnosperms is a very consistent struc- go BOTANICAL GAZETTE [AUGUST 4 ture, originating from the hypodermal layer of cells, and developing — a wall of several layers, the innermost one of which is usually differ- — entiated as the tapetum. The only general tendencies to be observed 4 are the gradual replacement of synangia by separate sporangia, and — the more rapid elimination of all evidences of an annulus (in the — general sense). It is noteworthy that in both these particulars the a cycadophytes, with their much more recent connection with th Cycadofilicales, are far behind the coniferophytes. THE OVULE , The origin of the ovule of gymnosperms remains in obscuri While the stamen and its sporangia repeat the corresponding struc tures of ferns, the ovules of Cycadofilicales and of Cordaitales are well organized, even in the modern sense, that their connection Wi This means a tremendous gap between the somewhat hypothetica Primofilices, on the one hand, and the Cycadofilicales and Cordaitales as we know them, on the other hand, a gap which there seems to b small probability of filling up with intermediate forms. the general changes that have occurred since. To select the most primitive type of ovule from among the Pal zoic forms that have been investigated is impossible, unless it assumed that those ovules which are most unlike the modern 01 following result. The oldest ovule had a single integument entirely free from the nucellus; in testa-formation this integument differ entiated into three layers, the outer fleshy, the stony, and the inne fleshy; the ovule was supplied with two sets of vascular strands, t ne outer set traversing the outer fleshy layer, and the inner set traversi the peripheral region of the nucellus; and the beaked tip of nucellus broke down more or less completely within the firm and resistant epidermis to form a pollen chamber. If these are rea the features of the most primitive known ovules, the changes becom very apparent, and they represent general tendencies, for they ap in every phylum. | : 1909] COULTER—EVOLUTION AMONG GYMNOSPERMS gI In the first place, the integument and nucellus, instead of remain- ing separate, develop separately only in the region of the nucellar beak. So early was this change that it probably represents the con- dition of the majority of the Paleozoic ovules, a condition which has persisted ever since. The method of development is very evident, the integument appearing first as a distinct annular growth about the base of the young nucellus, but later its basal meristematic zone _ becoming indistinguishable from that of the nucellus. In all proba- bility the change was brought about by the earlier appearance of the integument, and the result has been more or less variability in the amount of freedom from the nucellus. The three-layered testa persists remarkably throughout gymno- sperms, varying chiefly in the amount of development of the outer fleshy layer. The stony layer is always strongly developed, and at the maturity of the seed the inner fleshy layer always forms for it a papery lining. A strong development of the outer fleshy layer, result- _ ing in fleshy seeds, continues throughout the cycadophyte phylum __ and the Ginkgoales and is a feature of many of the Taxaceae. Among the Pinaceae the outer fleshy layer is present in the young integu- ment, but does not develop, so that the stony layer is the conspicuous superficial feature of the seed. The development of the outer fleshy layer among the Cycadales and Ginkgoales is phylogenetically con- tinuous from the Cycadofilicales and Cordaitales; but among the Taxaceae there is probably no such continuity, but a reappearance of the activity of this layer in certain genera. Among the Gnetales, the single integument of the other gymnosperms is replaced by two _ integuments, the inner fleshy layer having become differentiated as _ a delicate inner integument, which appears earlier than the heavier _ outer integument, which gives rise to the outer fleshy and stony __ layers. In Gnetum the outer fleshy layer develops the pulpy invest- ment characteristic of the primitive seeds; but in Ephedra this layer behaves as among the Pinaceae. If any general tendencies can be inferred from these facts in reference to the integument and testa 9 they are seen in the abortion of the outer fleshy layer in the largest 4 group of living gymnosperms, and in the final differentiation of the _ three-layered integument into two integuments. The vascular supply of the ovule exhibits a very evident progressive g2 BOTANICAL GAZETTE [aucusT ” change. When the integument and nucellus become free only in the : region of the nucellar beak, the inner set of vascular strands is shifted — from the peripheral region of the nucellus to the inner fleshy layer, : and this situation persists among the cycadophytes. Curiously — enough, it reappears in Gnetum, but in that case it is associated : with the presence of the two integuments. Among Ginkgoales the — outer set of strands is suppressed; among Taxaceae the inner set — is suppressed; and among Pinaceae both sets have disappeared. — The general tendency, therefore, is to eliminate the vascular strands 2 from the ovule; but it is puzzling to find both sets absent from the — older Abietineae, and one set still present among the younger Tax- a ineae. 4 The presence of a pollen chamber is one of the most conspicuous q features of the primitive ovule, and its association with fertilization by — ciliated sperms is so evident that it is natural that the two disap- — peared simultaneously with the establishment of Coniferales, but 4 the abruptness of the disappearance is evidently more apparent than real. The presence of an extraordinarily deep pollen chamber in = Ephedra can hardly be regarded as a contradiction to this general ~ statement, for in that case it is evidently of secondary origin, asso a ciated with a remarkably massive archegonium neck. : THE FEMALE GAMETOPHYTE 3 The female gametophyte of gymnosperms exhibits a progressivé series of changes which is significant because it leads toward the a angiosperm condition. At this point the very important historical — record fails, and the entire testimony must be obtained from living forms, which do not represent a series, but the ends of many series. For this reason, and also because such progress is always very uneq : in different forms, various stages of advancement may be expected to be found in forms grouped in a single alliance. The series, ther fore, is not so much one which conforms to recognized groups; as & series of stages each of which may be exhibited by members of various _ groups. . The general development of the gametophyte is quite uniform and since the same sequence of events occurs among the heterosporous- pteridophytes, it may be inferred that a knowledge of the ancient * 1909] COULTER—EVOLUTION AMONG GYMNOSPERMS 93 gymnosperms would not materially change this situation. The general sequence referred to in the development of the gametophyte is as follows: free nuclear division, usually accompanied by vacuola- tion which results at some stage in parietal placing; the formation of walls, resulting in a parietal tissue; the centripetal growth of this tissue until it reaches the center of the embryo sac; and the final growth of the gametophyte until it reaches its mature size. In certain cases there may be no parietal placing, the free nuclei remain- ing distributed throughout the embryo sac; and therefore there is no centripetal growth, but general wall-formation throughout the sac. The details of the formation of permanent endosperm tissue from the primary walled cells are variable and perhaps very important from the evolutionary point of view, but the range of forms from which these details have been obtained is far too small to make them of present service in this connection. The tendency which runs through gymnosperms as a whole, and which reaches its extreme expression among angiosperms, is to mature the eggs earlier and earlier in the ontogeny of the game- tophyte. In the most primitive condition of the gametophyte, the eggs do not appear until the endosperm is nearly full grown; and other gametophytes can be selected and arranged in a series showing the gradual slipping-back of the egg in the ontogeny of the game- tophyte, until in such a form as Torreya the archegonium initial is differentiated as soon as wall-formation has taken place. A conspicu- ous illustration of the inequality of response to such a general tendency among related forms is furnished by Torreya and Cephalotaxus, the archegonia not appearing in the latter genus until the gameto- phyte is well grown. The next stage is illustrated by the situation in Tumboa, in which eggs are matured before wall-formation is com- plete, resulting in the elimination of archegonia. The extreme stage in this progressive series of changes among gymnosperms is illus- trated by Gnetum, in which eggs are matured at the stage of free nuclear division, the most embryonic stage of the female gametophyte. So far as the living forms are concerned, the Cycadales and Ginkgoales show little, if any, response to this tendency; and there- fore possess the most primitive type of female gametophyte among q living gymnosperms. Among the Coniferales, on the other hand, 94 BOTANICAL GAZETTE [Avcust © alk stages are found, to the one just preceding the elimination of | archegonia; and this stage is attained by Tumboa and Gnetum. The general tendency of the archegonia among gymnosperms is to eliminate the ventral canal cell. The gymnosperms are distin- guished from the pteridophytes by the complete elimination of neck canal cells, and this tendency to suppress all of the axial row except the egg continues among gymnosperms. Among the living forms, | present among the ancient gymnosperms. In the other living groups the wall has disappeared, and the ventral canal cell is repre- sented by a free nucleus. In certain forms even this nucleus may have disappeared; and of course there is no trace of it when t archegonia are eliminated. The distribution of archegonia may be considered in this connec tion, although the tendencies do not appear general. It is becoming evident that the position of archegonia is related to the position of the pollen tube, which often reaches the embryo sac before the arche- gonium initials are selected. In cases where the pollen tube assumes a lateral position in reference to the gametophyte (as in Sequoia and Widdringtonia), it has been demonstrated that the latter responds by the selection of numerous deep-seated and laterally placed arche- gonium initials. It may be inferred, therefore, that the usual micro- pylar position of archegonia is due to the usual micropylar position of the tip of the pollen tube. It may be that numerous scattered and sections of Paleozoic ovules that reveal archegonia, and also the archegonia of heterosporous pteridophytes, suggest the opposite ¢ clusion. In any event, they tend to become definite in number and are then organized in two ways: either as individual archegoni . each with its own jacket and chamber; or as an archegonial complex, with a common jacket and chamber. The latter may seem tO a specialized condition, exhibited chiefly by Cupressineae, but ™ also seems to be the natural condition from which to derive the free eggs of Tumboa and Gnetum when archegonia are eliminated ontogeny. 1909] COULTER—EVOLUTION AMONG GYMNOSPERMS 95 THE MALE GAMETOPHYTE It is perhaps impossible as yet to determine the character of the male gametophyte of the Paleozoic gymnosperms. The evidence is accumulating that it comprised many more cells than do the game- tophytes of most living gymnosperms; but it is not demonstrable whether these supernumerary cells were vegetative or spermatogenous. There are instances of supernumerary cells of both kinds among living gymnosperms, so that they furnish no clue; and the same is true of heterosporous pteridophytes. The balance of probability, however, is in favor of the view that they were in the main sperma- togenous. : In any event, starting with the known condition among hetero- sporous pteridophytes, the tendency among gymnosperms has been to reduce and finally to eliminate the vegetative (prothallial) tissue; and to reduce the sperm mother cells to two. In certain groups (as Abietineae) the prothallial cells are two in number; in others (as cycads) there is one prothallial cell; and in still others (as Taxodineae, Cupressineae, and Taxineae) prothal- lial tissue has been eliminated. Such prothallial cells as do appear are sometimes persistent and sometimes ephemeral; so that the evi- dence of a disappearing tissue is complete, and it actually has dis- appeared in what are recognized as the most modern groups. The situation common to Podocarpineae and Araucarineae is usually cited as an illustration of a more extensive and therefore a more ancient prothallial tissue, which connects directly with the “ multi- cellular” pollen grains of Cordaitales. This may be true, but all of the extra cells are derived from two primary ones, which hold a definite place in the ontogeny of the gametophyte; and therefore may repre- sent a secondary tissue that holds no phylogenetic relation to the more extensive prothallial tissues of older forms. In any event, it is ephemeral, breaking down and liberating its nuclei. The number of sperm mother cells is so rigidly two, that this reduc- tion may be said to have been accomplished by all living gymno- sperms, whatever may be the fact in reference to the Paleozoic gymno- sperms. It is interesting to note that the very few instances of a greater number of sperm mother cells occur in one group character- ized by its retention of ancient features (Cycadales), and in another 96 BOTANICAL GAZETTE [avcust 3 group characterized by its very modern features (Cupressineae). 4 While phylogenetic continuity of multiple sperms might be claimed q for Cycadales, no such claim could be maintained for Cupressineae. : E The greatest epoch in the history of the male gametophyte of gymnosperms, however, was the abandonment of ciliated sperms, 4 and this occurred in connection with the establishment of Coniferales. — It is not generally appreciated that five of the seven recognized pri- = mary groups of gymnosperms possess ciliated sperms, and that the 3 modern type or completely’terrestrial type of sperm was introduced by — the conifers. This also affected the pollen chamber, the pollen tube, ~ and the cell generations in spermatogenesis. The pollen chamber 4 disappeared; the pollen tube ceased to be exclusively a branching — haustorial organ and became a sperm-carrier; while the last cell- generation in spermatogenesis was omitted. It is this condition of a spermatogenesis that is carried forward by angiosperms to a still greater stage of reduction. Just what cells are eliminated and what 4 cells remain is a question of small importance. The significant fact a is that spermatogenesis is shortened, and the ultimate cells, although non-ciliated, are physiologically sperms. THE EMBRYO The absence of embryos from the seeds of Paleozoic gymnosperms — indicates that some great change connected with embryo-formation was introduced by the Mesozoic gymnosperms. It would be of extreme interest to know the ancient condition, but we know only what it has become. After this change, whatever it may have been, the proembryo has become the structure showing steady and pe gressive change. a The first stage in the development of the proembryo is free nuclear : division, followed by wall-formation; and in the most primitive 9 condition the free nuclei are so numerous that wall-formation results ag in a tissue which fills the egg. The tendency is to reduce the numbet — of free nuclear divisions, resulting in a reduction of the amount of 3 proembryonic tissue, so that more and more of the general cytoplasm : 3 of the egg is left free from tissue. The proembryo of Ginkgo has is retained a very primitive character; and illustrations of early stag® _ in the reduction of the proembryo may be observed among the cycads: 2 ne Laws i ih da) Tg909] COULTER—EVOLUTION AMONG GYMNOSPERMS 97 _ In Zamia, for example, which illustrates the extreme amount of reduction among cycads, the proembryo is a relatively small amount of tissue at the base of the egg. Among the Coniferales this reduc- tion has been carried forward to a much greater extent, 16 free nuclei appearing sometimes, 8 free nuclei being the prevailing number, and 4 free nuclei being occasionally attained. This results in a pro- embryo consisting of a small and definite number of cells, with dis- tinctly distributed functions. Now and then among gymnosperms ° (as in Sequoia), there is no free nuclear division, but these are inter- esting rather than significant exceptions. Even among the Gnetales itis found that a certain amount of free nuclear division precedes wall-formation. That this reduction of the free nuclei before wall- formation is significant, is shown by the fact that among angiosperms free nuclei have disappeared, and wall-formation accompanies the first division of the egg-nucleus. THE UNIVERsITY oF CHICAGO ON SIMILARITY IN THE BEHAVIOR OF SODIUM AND POTASSIUM Ww. I. V. OSTERHOUT (WITH FOUR FIGURES) It is commonly-mentioned by textbooks, as worthy of remark, that sodium and potassium agree closely i in chemical behavior, but differ : fundamentally in their effects upon plants. 7 This general statement is founded on the study of the nutritive — functions of sodium and potassium. There is no a-priori reason f supposing it to be true in the field of toxic or of protective action. a As this is a point of general interest I have made some experiments — with reference to it. 4 Two extensive series of experiments, one on sodium, the other on 4 potassium, were carried on simultaneously. They were found to — ‘show a remarkable degree of agreement in the action of these two 4 substances. 4 The experiments relating to sodium have already been described,’ q while those on potassium have been withheld from publication, pend- ing thecompletion of further observations on the mutually antag: onistic action of sodium and potassium. = Most of the experiments were made with a variety of wheat known a as Early Genesee. The technique has been fully described in 4 4 previous paper.? : TOXIC ACTION : —a In the earliest studies which I made on balanced solutions, I we struck with the fact that Na and K agree closely i in their toxic effect 08 plants. These results I have found to hold in an extensive series of expetl ments, including algae, liverworts, Equisetum, and some thirtee? genera of flowering plants. While there are doubtless some excep: tions, the general rule seems to be that Na and K are closely si in their toxic action. ' Jahrb. Wiss. Bot. 46:121. 1908. 2 Bot. GAZETTE 44: 266. 1907. Botanical Gazette, vol. 48] 1909] OSTERHOUT—BEHAVIOR OF SODIUM AND POTASSIUM 99 The most careful quantitative studies which we possess on this point are those of Miss Macowan.3 These studies show that the toxicity curves for K and Na are practically identical, while the cor- responding curve for Mg shows a much higher, and that for Ca a much lower degree of toxicity. ANTAGONISTIC ACTION* The antagonistic action of monovalent kations on each other has especial interest in view of the experiments of Lorss on Fundulus, which offer a certain analogy with those of LInDER and Picton.° In these experiments monovalent kations antagonized bivalent but did not antagonize other monovalent kations. | The curve of antagonism between NaCl and KCl shows two maxima. The location of these maxima, however, is not constant, but varies somewhat in different series of experiments. Table I and jig. show the average result of four series. The antagonism G H Fic. 1.—Antagonism curve, NaCl vs. KCl. The ordinates represent millimeters of sonh él the roots of wheat. The shies at A represents the growth in pure NaCl, that at P the growth in pure KCl. The other ordinates represent growth in mixtures of NaCl and KCl, the proportions of which are found opposite the corre- sponding letters in table I: thus the ordinate at H represents growth in a mixture o Toote NaCl+ rooce KCl. is comparatively slight. I have also noticed antagonism between Na and K in liverworts. Table II and jig. 2 show that both Na and K antagonize NH,, and that their effects are very similar. 3 Ibid., 45:45. 1908. 4 Cf. facts and literature hes by KEARNEY and CaMERON, Rept. No. 71, oa Dept. Agr. 1902; and by BENECKE, Ber. Deutsch. Bot. Gesells. 25:322- 1907- 5 American Journal of a 3:327- Igoo. ° Cf. HoBeR UND Gorpon, Hofmeister’s Beitr. Chem. Physiol. si Pathol. 5:432. 1904. 100 BOTANICAL GAZETTE [AUGUST TABLE I WHEAT cogedee DURING 30 DAYS). ALL QUANTITIES GIVEN ARE CUBIC. CENTIMETERS OF 0.12 ™ SOLUTIONS Corresponding ie gui length Culture solution point on of r nied r plant curve (jig. z) NACI. eae A 55 too NaCl} Kcl N PP a tear a aera B 75 too NaCl o KCI Hes batepe hes : 80 too NaCl KCl t ae g G ie Bear oy D II5 ee Dt fees dates E 120 too NaCl } 35 RC} J gk owe a le ere F j 130 too NaCl 50 KCl { sey Wliete eae G 121 too NaCl I0o KCl ; 2 W 6 Oe 2 Se we 8 H 85 50 NaCl 100 Kcl er oe et ete eee I 75 35 NaCl KCl PENS oly ses J 80 25 NaCl KCl Sea wae gie vp dy F 95 15 NaCl) Kcl 5 athe le PERS M T0900 Io NaCl i 100 Kcl FES ee hee halts N 95 5 NaCl 100 KEL eS Ae ee ern oO 85 RO ae P 65 5 ho ee Distilled water, 725mm KCl NaCl mm. NH,¢Cl A B ¢ 4D E& FGH Fic. 2.—Antagonism curve, NH,Cl vs. NaCl (upper curve -x-x-x-) and NBC vs. KCI (lower curve -o-o-o-). Each ordinat nts the amount of - 38: . Mbperteas: in a solution whose composition is given opposite the coresponing ee - in 1909] OSTERHOUT—BEHAVIOR OF SODIUM AND POTASSIUM WHEAT (GROWTH DURING 30 DAYS). IOl TABLE II ALL QUANTITIES GIVEN ARE CUBIC CENTIMETERS OF 0.12 m SOLUTIONS Correspondin Aggregate length _ Culture solution ena on ponte point on curve Culture solution of roots per er plant in mm, (fig. 2) plant in mm NEC Joes arse 6.2 A NH Cha ares 6.2 too NH,Cl too NH,Cl NaCl cy tee 3r B KCl Pe Ger 27.5 40 NH,Cl 40 NH,Cl 100 NaCl t ees 52 C roo EC f one 46 20 NH. Ch 20 NH ct 100 Natt { er ga 74 D cr Seer oe 62 10 NH,Cl to NH,Cl 100 NaCl ; MO paree 80 E KCl ; #2-5 5 NH,Cl 5 sec I0o NaCl ; Fails 85 F or RL 75 ENE! t NH,Cl me oy ; ee. 67 G ee ee 68 NaCl 6. .<¢ 2. ee 55 H KEL G a. | 66 Distilled water, 725 ™™ Experiments with magnesium show that it is antagonized in about the same degree by both Na and K (table III and fig. 3). 3-—Antagonism curve, MgCl, vs. oc peee curve -x-x-x-) and MgCl. v -0-0-~ represents the amount of growth of w roots in a sol table MgCl, given Opposite FE corresponding letter in Til whose composition is 102 BOTANICAL GAZETTE [sucust TABLE III WHEAT (GROWTH DURING 30 DAys). ALL QUANTITIES GIVEN ARE CUBIC CENTIMETERS OF 0.12 m SOLUTIONS é Aggregate length} Corresponding : |Aggregate length — 4 Culture solution of roots per point on curve Culture solution of roots per plant i fin (Gig. 3) plant inmm Moccia, 5 A ii 2 Gl Se eae 5 too MgCl 100 MgCl 10 eer Bee 7°5 B ro Kel Z' ees 7-5 too MgCl too MgCl 25 ig tenses 10 c = 2 See 8.7 too MgCl too MgCl go NaCl § 0050 13-7 D on 12.5 too MgCl, too MgCl, too NaCl eee 25 E Kel ee ee 21 60 MgCl,)...... 60 MgCl 100 mart 37-5 F g 2 Pas 34 40: MgCl, o MgCl, , too NaCl Rowe tse poe G a KG i Sera 48.7 MgCl 25 MgCl so Neer bo 90 H os ied ne 84 20 MgCl, MeCl : zoo NaCl meee a2 I fa Kel ud eee 99 15 MgCl 15 MgCl, 2. Bes or Pees 140 J ei rc ee 125 oO MgCl M ] > 200 heck : veteee 176 K So a9 a f gaecds 152 MgCl oi Nec | nis a6 L 7-5 MgCl, a él 5 MgCl, MgCl t00-MNaCl. $25" val bas M ae 43 See Be 135 INSU Gao 55 N 7 | ae ee 66 Distilled water, 725 mm In algae I have found that MgCl, is much more strikingly antago- nized by KCl than by NaCl. a The experiments with calcium show a more marked antago : nism than any of the other cases. We find that Ca is antag- — onized to a slightly greater degree by K than by Na (table IV and jig. 4). Similar results were obtained with algae, liverworts, Equisetum, and some fifteen genera of flowering plants. From the facts here set forth it is clear that in their toxic and JUM 10 ] OSTERHOUT—BEHAVIOR OF SODIUM AND POTASS 3 1909 i imilarity. As protective effects sodium and potassium show great similarity i iti ts, we this does not seem to be the case in the field of nutritive effects, 500 _ mm. 1, vs. i -X-x-) and CaC 2 Fic. 4.—Antagonism curve, CaCl, vs. KCl (upper ie sei al growth of NaCl (lower curve 0-0-0). Each ordinate repress ite the corresponding Wheat jroots in a solution whose composition is given Oppost letter in table IV 104 BOTANICAL GAZETTE . ; [aucusr seem to have in this case a means of distinguishing clearly between nutritive and protective action. 3 TABLE IV WHEAT (GROWTH DURING 30 DAYS). ALL QUANTITIES GIVEN ARE CUBIC CENTIMETERS OF 0.12 m SOLUTIONS : |Aggregate length} Corresponding le Aggregate length 4 Culture solution of roots per point on curve Culture solution bo : plant in mm ( | antl in inde CaCl, .....-... 85 A BOT cen 85 too CaCl, too CaCl, | 10 NaCl : Saha 100 B to KCl pews 105 too CaCl, : : too CaCl, 25 NaCl oh wraeiete 117 Cc 25 KCI ear ae See | 125 too CaCl too CaCl 50 NaCl t ee 50 D 50 KCl Be Sy ea 174 Io0o0 CaCl, : 00 CaCl, | too NaCl ; reiseen 198 E oo KCl oe | 230 50 CaCl, o CaCl, | TOO UNaGh yo 262 ig s KCl i eereee| 337 25 CaCl, ) 25 CaCl, too Nach 407 = 342. G eel Rie 420 oben 15 CaCl, 100 NaCl f BSE 39° H in een ae 464 to CaCl 1o CaCl, 100 Na on ries 5d 416 I ao EC) Creeseegce 492 5 CaCh " CaCl, 200 NACL Ss — ee oe fac 507 rt CaCl t CaCl | 100 NaCl ; Paws ese 300 K 16s KCL teens 3.46 NaCl Mike weary 55 5 ae 66 Distilled water, 72 5 ma SUMMARY The accepted idea that sodium and potassium have entirely different effects upon plants is not valid in the field of toxic and protective action. Here their behavior shows the close similar! which their near chemical relationship would lead us to expect. UNIVERSITY OF CALIFORNIA BERKELEY ede oS oa lie es. SL Ei os TOXIC AND ANTAGONISTIC EFFECTS OF SALTS AS RELATED TO AMMONIFICATION BY BACILLUS SUBTILIS CHas. B. LIPMAN (WITH FIVE FIGURES) In the science of bacteriology, especially in that of soil bacteriology, our work has thus far only taught us enough to give added zest to investigation and the most important and interesting results are still forthcoming. RAMANN (23) well expresses it when he says, “In spite of numerous and important investigations we are still but in the first stages of our researches on bacteria and only at the very starting-point in our knowledge of soil bacteria.” In his haste to classify bacteria, to show their direct relation to many diseases, to apply his knowledge of them to the practical side of the dairy industry, and finally, to measure the net results of the activities of bacteria in the soil, the bacteriologist has left almost untouched one of the most important phases of the science of bacteriology, namely, the physi- ology of bacteria, which is of great scientific interest and practical importance. Especially is this true of the physiology of soil bacteria, which remains as yet a closed book, and since the writer is devoting his time to researches on soil bacteria in particular, it was thought best at first to experiment with some of these organisms. It may also be added that in California, with its thousands of acres of waste alkali land, and in similar regions elsewhere this study will undoubtedly prove to be of the greatest practical significance, especially when we have learned to coordinate the results obtained in similar investiga- tions on the higher plants with those derived from researches on soil bacteria. Since ammonification is the first great step in the transformation and simplification of the organic soil nitrogen, it was thought best to study the effect of various salt solutions on pure cultures of ammon!- fiers first. The work was carried out along the same general lines as to the preparation of solutions as the experiments of LorB on the _ effects of salt solutions on various forms of animal life, and the subse- 105} [Botanical Gazette, vol. 48 106 BOTANICAL GAZETTE [aucust quent experiments of OsTERHOUT on the higher plants. It was indeed — the insight of the latter investigator which led him to conclude some ~ time ago that a proper understanding of physiologically balanced solutions in relation to plants and to soil bacteria would render the 4 control and successful cultivation of alkali lands a much simpler — matter than it has been, and this will undoubtedly prove true in the ~ near future. In the selection of an ammonifier which could be used uniformly throughout all the experiments, the writer was guided by the work of 7 MARCHAL (15), to whom indeed we owe what little knowledge we ~ have of the physiology of ammonifiers. Among the best ammonifiers 4 found by that investigator were B. mycoides, which changed 46 pet — cent. of nitrogen into ammonia in a given time, Proteus vulgaris (36 — per cent.), Sarcina lutea (27 per cent.), and B. subtilis (19 per cent). Since the last form is easily isolated and cultivated and is a strong ammonifier, it was decided to use it in the following experiments. It is more than probable that the same relative results will be obtained with any ammonifier; this, however, will be tested in other expéer- ments now contemplated by the writer. The pure culture of B. subtilis employed for inoculation through all the series of experiments was obtained from soil from Auburn in the foothill fruit region © California. The salts tested were the chlorids of sodium, potassium, calcium, and magnesium. Only chemically pure salts were used, after sub- mitting them toa flame test. Molecular or bimolecular stock solutions in distilled water were made, from which the requisite amounts were taken for the various concentrations. Witte’s peptone was the nitro- genous substance used for the ammonification, of which 1 per cent. solutions were employed in the tests for the single salts and 0.75 Pe cent. in the binary solutions. The method of inoculation employed W4S as follows: Inoculation is made from peptone agar slope of B. sub- — tilis into a sterile 100° portion of 1 per cent. peptone in a 25% — Erlenmeyer flask. This is incubated for forty-eight hours at 28° Cs at the end of which time the membrane that forms on the surface of the culture is precipitated by slight shaking, and then by tilting the flask to one side and carefully setting it down again, the liquid cove™ ing part of the bottom of the flask remains free from membranous he ~— ints RE pate en meen Pane Te free er mA, oe igog| LIPMAN—EFFECTS OF SALTS ON BACILLUS 107 material and is homogeneous in character. Of this homogeneous liquid 1°° was drawn off with a sterile pipette for inoculation into each flask to be tested, the greatest caution being used to prevent any particle of membrane from entering the pipette as the liquid was drawn up. This was the most satisfactory method of inoculation of several tested and yields concordant results in the duplicate series. All the solutions employed were made practically neutral. The ‘incubation was carried out in a thermostat at a temperature which varied between 28° and 29°C. The incubation period was two days in the case of the single salt solutions, and two and one-half days for the binary solutions. The amount of ammonia formed, which was used as a criterion for establishing the efficiency of B. subtilis in the various solutions, was determined as follows: At the end of the incubation period the culture solutions were transferred to flat-bottomed Jena distillation flasks, diluted to 300-350°°, an excess of magnesium oxid added, and distilled. The amount of ammonia in the distillate was titrated against standard acid, cochineal being used as the indicator. Sterile blanks were run on all determinations, each of which was made in duplicate, and the tables given below represent averages of at least three sets of such duplicates and in some instances of five and six sets of duplicates. Experiments with single salts In determining the salts to be tested the writer was guided by the alkali and alkaline earth constituents-of soils. ‘The sodium, potas- sium, calcium, and magnesium salts are important factors in plant nutrition and are always present in soils; in some cases, indeed, one or more of them may be present in such excess as to inhibit plant growth materially and in some instances completely. Such soils we find in California and other states under the common appellation of _ “alkali lands.” It was decided, therefore, to test the salts of the alkalies and alkaline earths above mentioned, to determine the degree of toxicity of each for the bacteria experimented upon. Since from similar work on animals and plants, the anion of salts was found to have comparatively little effect, a chlorid of each metal was _ €mployed for the sake of uniformity. 108 BOTANICAL GAZETTE [AucU SERIES I. SODIUM CHLORID 4 There were prepared sixteen Erlenmeyer flasks (125°° capacity), each containing 50°¢ of solution, made up as follows: The first flask contained 50°° of 1 per cent. peptone solution in distilled water; the second contained a 0.1 m solution of NaCl and 1 per cent. peptone; the third flask contained 0.2 m NaCl and 1 per cent. peptone; and so on, the concentration of NaCl increasing by 0.1 m in each succeed- ing flask up to the sixteenth, which contained 1.5 m NaCl and 1 per cent. peptone. All the flasks were plugged with cotton, sterilized in ” the autoclave at a pressure of 1.25 atmospheres, and when cool were inoculated from a culture of B. subtilis in the manner above described. | After two days’ incubation at 28° to 29° C., the ammonia formed in” the peptone solutions was distilled off and determined as above | explained. Table I shows the results. ; 4 Plotting a curve by laying off the con TABLE I centrations as abscissae and _ the milli a we caus grams of N (as NH,) as ordinates (jig. 1); ’ gent tenths ™ | formed as NH, | We note the following: NaCl up to a con-_ % wae centration of o.1 m stimulates B. subtilis” : ati as an ammonifier, but beyond that con” 3 2.80 centration it becomes gradually more — “ be and more toxic, and at 1.3 m we find” 6 2.38 scarcely any ammonification. It is evr 8 tf dent, also, that NaCl is not nearly a_ 2 ee toxic for B. subtilis as it has been found — it 1.05 by Logs (8, p. 412)' and OsTwALD (21) be aes to be for animals, and as OsTERHOUT i: — (17) and MacGowan (14) have found it : to be for plants. Lors found, for stance, that the formation of embry in the eggs of Fundulus was rendered impossible in a 0.625 m placed in a 0.0937 m solution of NaCl usually died within a few mi t See also § and literature there cited. : T909] LIPMAN—EFFECTS OF SALTS ON BACILLUS 109 utes, and further, that even at a dilution of 0.0001 m NaCl proved poisonous to the young plants. The results above given serve, how- ever, to confirm again the general principle, formulated by Logs, of the toxicity of NaCl alone for living organisms. Fic. 1.—Toxicity curves of KCl, NaCl, MgCl,, and CaCl,. The ordinates rep- resent milligrams of ammonia nitrogen. The ordinate at o represents the amount of ammonia nitrogen formed in a blank culture (x per cent. peptone in distilled water). The abscissae represent concentrations in tenths molecular. SERIES Il. CALCIUM CHLORID Here the experiment was carried out in the same general way as i series I, CaCl, being substituted for NaCl, and, owing to the extreme toxicity of the former, solutions ranging from 0.1 m to 0.6 m only were prepared. The ammonia was determined as above and the results are shown in table II. ITO BOTANICAL GAZETTE [avucusr Here again (see fig. 1) we find agreement between the toxic action of CaCl, on bacteria with that of the same salt and other calcium salts : on animals as shown by Loes (8, p. 425) in the case of Fundulus, and by Ostwatp (21) in his work on the freshwater Gammarus. It is’ 4 well to note here alsothat an examination — fe of the. four” curves (fig. 1) for the salts a groped Miligams of N employed reveals the fact that CaCl, is ; CaCl, solution > easily the most toxic of all for B. subtilis. — ° 5.60 This fact is of especial interest because q ; a of its wide disagreement with the facts — : hs obtained by experiments on plants with 5 0.00 CaCl,, in which Macowan (14), for ex-— : soos ample, found it to be the least toxic of the — four salts for wheat (variety Early Gene- — see). In this respect therefore, if B. subtilis may be considered — representative, bacteria exhibit the physiological characteristics — more typical of animals than of plants, with which they are now — classed. We see above, that even at a concentration of 0.3 m J CaCl, the formation of ammonia by B. subtilis is inhibited. ; SERIES II. POTASSIUM CHLORID > 4 The experiment was arranged as those preceding it and ec : results are shown in table III. : On examining the curve (fg. 1) ob: TABLE III tained from these results we see at once ‘ Numbers repre- Milligrams ms of the strong resemblance of it to that oe |e Mth obtained with the solution of OE” 7 aoa <.60 although at the concentrations employed : 4.55 KCI exhibits no stimulating effect, it may : re show it at some concentration lower than 4 539 o.1 m. This general agreement of the 8 287 chlorids of K and Na has been found to ‘ ee be even more striking by Macowan (14) 9 she in a_ series. of experiments on wheat. obs Here, therefore, B. subtilis exhibits phys- ae hip iological characteristics akin to those t4 0.07 of the higher plants and differing widely 2 oo | from those of animals, as shown, ~ for =i tool : B ; F T909] LIPMAN—EFFECTS OF SALTS ON BACILLUS III example, by the work of OstwaLp (21) in which KCI showed the most extreme toxicity of all the salts tested. It is also worthy of mention here, as shown above, that the KCl curve declines more gradually than the sodium curve beyond the concentrations of o.1 m. SERIES IV. MAGNESIUM CHLORID In the curve drawn on the basis of table IV (fig. I) we notice a parallel to the toxicity curve for CaCl,, except that MgCl, is not nearly as toxic for B. subtilis as the former. While a 0.3 m solution of CaCl, totally: ins: jee hibits the ammonifying activity of B. subtilis, Numbers repre- Milligrams of N - : * sent tenths m cH; the latter will make a fair growth in a solu- MgCl, solution| formed as N TABLE IV tion of MgCl, of like concentration and form ° 5.60 an appreciable amount of ammonia. Here ; nares again, we find agreement between the be- 3 ao havior of B. subtilis and Fundulus in solu- 5 a pi tions of MgCl,, as Lors (7, p. 411) found that in an m/2 solution of MeCl, no embryo develops in the eggs of Fundulus, but that the same degree of toxicity is reached in an m/8 solution of Ca(NO,),, thus showing the mag- nhesium salt to be less toxic than the calcium salt. On the other hand, as shown by Macowan (14), MgCl, is far the most toxic of the four chlorids employed in experiments on wheat; and in this respect the behavior of B. subtilis resembles that of Fundulus rather than that of the higher plants. Experiments with binary solutions The fact that the results obtained were in such striking general agreement with those of the investigators above mentioned on animals and higher plants was sufficient stimulus for further inquiry into the biochemistry of ammonification. It was deemed of interest, therefore, to see if antagonism between salts holds as well for bacteria as it does for the higher forms of life, with the end in view of ascertaining whether ’ balanced solutions are necessary for bacteria, and whether solutions _ balanced for the other forms of life investigated will prove the same eet we A ee oh for bacteria. The remainder of this paper will deal with the an- tagonistic effects of one salt on another in binary solutions, while tr3 BOTANICAL GAZETTE [AUGUST the establishment of a balanced solution, with other work now con- templated by the writer, will form the subject of another article. SERIES V. POTASSIUM CHLORID vs. CALCIUM CHLORID In these experiments the technique was somewhat different from the foregoing. All the salts were used at a concentration of 0.35 m? and mixed with each other in various proportions in Erlenmeyer flasks of 250°° capacity. Two or three liters each of KCI and CaCl, solution of the concentration above noted were made up to contain Kang, . ©.75 per cent. peptone.’ In each flask of the Zong, first half of the series were placed 100°° of the KCl-peptone solution. To no. 1x nothing was added; to the others up to no. 6 there were Yémg. added respectively 5, 10, 25, 50, and 100° of the CaCl,-peptone solution. Then beginning at the other end of the series each flask received Shelia too°° of the CaCl,-peptone solution. Flask no. 11. contained this alone; to the preceding ones in order were added respectively 5, 10, 25; te 50, and 100°° KCl-peptone solution, the . two halves of the series meeting in no. 6, as shown in go the curve (fig. 2) and table V, at the combi- PS, BDU PMNs Ae Cal AGT SAG Oe e ee" Joe a 5, mire nation of 100°¢ of each solution. In order to keep the volume the same in all cultures they were thoroughly mixed, and enough solution draw? off with the pipette, where additions were made, to make all the culture 2 This concentration was chosen because it was about the concentration of NaCl in sea water of San Francisco Bay. 3 This concentration of peptone was used in all the experiments with binary solutions. ee er eke ee ee a A ea ee ee eee Bn ae eee 1909] LIPMAN—EFFECTS OF SALTS ON BACILLUS 113 solutions have a uniform bulk of 100°, thus avoiding any differences in the supply of oxygen to the bacteria by having an equal surface of liquid exposed to the air in each flask. As in the case of the single salt solutions, duplicates were run on all the cultures, and also sterile controls, so as to allow of a deter- mination of the ammonia actually formed by the bacteria. The solutions were all sterilized in the autoclave at 1.25 atmospheres, inoculated as above, and incubated for two and a half days at 28° to 29° C., after which they were distilled, as in the case of the single salt cultures, and the ammonia determined. The results obtained follow, with the curve plotted from them in accordance with the arrange- E : : ALL QUANTITIES GIVEN REFER TO CUBIC CENTIMETERS OF 0.35 ## SOLUTIONS Culture solution Lip yeni per _ Heb KC es ss K ores es CaCl, : i 21.46 mi ack, . Nee EER if 18.83 ee CaCl, : H 9-00 "So CaCl, § G 6.44 se CaCl F 6.30 too Ot: Pepa E 4-55 100 Gch. arieeipae Sate D 0.25 ns eee : cC 0.14 o Be ; seus GAS B 0.25 WOO Cai gear yn A 0.00 ment employed by OsrerHouT (19). The letters along the axis of abscissas represent a given combination of the two salts as indicated in the table, and the ammonia formed is laid off on the axis of ordinates in numbers representing milligrams. We see at a glance (fig. 2) that there is a strong antagonism II4 BOTANICAL GAZETTE [AucusT : between CaCl, and KCl. Osternovrt (20) obtained a similar curve — for the antagonism between the same two salts in his experiments — on wheat. It is particularly interesting to note that both for wheat — and for bacteria the maximum point of the curve is at the combina- — tion of roo°* KCl solution and 5°° CaCl, solution, notwithstanding — the wide difference between the materials employed in the two cases, — and further despite the fact that the Ca ions are most toxic for B. subtilis and least toxic for the wheat. Again we find the strong antagonism above obtained is in strik- ing accord with the results of Lorn in similar experiments on animals, — both as to development (7) and as to muscular contraction (6). j SERIES VI. SODIUM CHLORID vs. MAGNESIUM CHLORID In this series the experiment was arranged and carried out in the — same manner as the one preceding, except that the salts used were — different. The ammonia formed at the end of the period of incuba- tion was determined with the following results: TABLE VI ALL QUANTITIES GIVEN REFER TO CUBIC CENTIMETERS OF o. 35 m SOLUTIONS Culture solution | Corresponding | Milligrams of N POG NO pra K 22.36 too NaCl } 5 MgCl, § *7-"°7°* a 23.75 too NaCl pa, Vo eens I 28.67 too NaCl 25 MgCl, Sete oe H 24.56 too NaCl 50 MgCl, BT as is 18.67 too NaCl 100 MgCl ae et oe F 10.49 50 NaCl 100 MgCl, Sian ce Se er oe ee ee ) E 4 84 25 NaCl | , MgCl, Sirk de pe | D 3.80 to NaCl 10d MgOly hosts se | Cc 3-54 5 NaCl ‘oe gCl, Royce eine ere B 3-36 500 JAMULS 6 aie A 2.13 1909] LIPMAN—EFFECTS OF SALTS ON BACILLUS 115 In the curve plotted from table VI (fig. 3), we note again a strong antagonism between the two salts tested, though it is not as marked as in the last series. ‘The curve proves to be more regular than the last, probably owing to.the fact that there was practically no variation in the temperature throughout the period of incubation. As Lrp- “kg 4mg NAEP Eo Sse: Mol), Ee Le 7 DO CBA 9% Fic. 3.—Antagonism curve, NaCl vs. MgCl. The ordinate at K repre : od = ammonia nitrogen in milligrams formed in a pure NaCl solution. The ordinate at A represents th "Ses ae formed in a pure MgCl, solution, and the ondhontes at the intermediate points represent the amounts formed in various com- binations of the two salts as indicated by the corresponding letters in table VI. MAN (4) has demonstrated, a constant temperature and equal periods of incubation are essential factors in quantitative work in ammonification, if results are to be considered comparable. — 116 BOTANICAL GAZETTE [AUGUST It is a significant fact that here again the maximum point on the curve nearly coincides with that of a similar curve obtained by OsTERHOUT (19) in his experiments with the same salts on root development in wheat, and exactly coincides in the case of a fungus (Botrytis cinerea); and though OsteERHOUT employed such widely varying concentrations as 0.12 m in the case of the wheat and 1.5 m in Botrytis, the maximum development was reached in a mixture of 10° of the MgCl, solution (or 7.5°° for wheat) and 100°° of the NaCl solution, just as was the case in ammonification by B. subtilis. In his experiments on the eggs of Fundulus and the sea-urchin (Arbacia), Lors (10) found that in a mixture of 98°° 5n/8 NaCl and 2°¢ rov/8 MgCl, all the eggs of Fundulus form embryos, whereas in pure NaCl or MgCl, solutions alone no embryos would form, and even in a mixture of equal parts of the above-mentioned solutions 75 per cent. of the eggs formed embryos. On the other hand, Ost- WALD (21) found in his work on the freshwater Gammarus that, so far from exercising an antagonistic effect on each other, the com- bination of Mg and Na chlorids proved more poisonous than either alone. SERIES VII. MAGNESIUM CHLORID vs. CALCIUM CHLORID The arrangement of the experiment and the ammonia determina- tions were. carried out in a manner similar to that employed in the two preceding series, two bivalent salts being tested this time. The results were as shown in table VII, p. 117. By an examination of the curve drawn on the basis of table vil (fig. 4) we are confronted by the very striking instance of lack of antagonism between the two salts. On the contrary, there is 2 Co” stant increase of the toxic properties of each when the other is added ‘to it in increasing amounts. In this exceptional behavior, so far a5 the writer can ascertain, B. subtilis (and probably all the ammonifiers) stand alone, when their physiological efficiency in such salt mixtures is compared with that of the higher plants and animals. No instance of such behavior on the part of any member of the latter two groups of organisms has come to my notice in reviewing the results of similar researches. An antagonism between CaCl, and MgCl,, though slight, Miler oP a ee 1gog] LIPMAN—EFFECTS OF SALTS ON BACILLUS 117 found to be none the less definite by Lors (6) in experiments which showed that sea-urchin blastulae and gastrulae would swim about TABLE VII ALL QUANTITIES GIVEN REFER TO CUBIC CENTIMETERS OF 0.35 ™ SOLUTIONS Culture solution Corresponding | Milligrams of N points on curve formed as NH; 100 MgCl ea isos K 3.08 too MgCl, e Cac. Gk = J 2.59 too MgCl, baa See I 1.68 too MgCl, 25 CaCl t Srna H .98 too MgCl, 50 CaCl, ; ee oe G “21 too MgCl sie CaCl, erate ae F .O7 50 MgCl a3 CaCl, Rg ieee E 00 25 MgCl 100 CaCl, o -C6R oa) .€, O-OH6 D oo to MgCl — ot pa se Cc 00 5 MgCl 100 CaCl, o's Sele ee ee B -0O0 1600 Cah 3 ee ps -49 in a mixture of the salts above mentioned for forty-eight hours, while each salt by itself would immediately prove poisonous at the concen- IG. 4.—Non-antagonism curves, CaCl, vs. MgCl. The ordinates at K repre- sent the ammonia nitrogen in milligrams formed in a pure MgCl, solution. The ordinate at A represents the amount of ammonia nitrogen formed in a pure CaCl. solution, and the ordinates at the intermediate points represent the amounts formed in various combinations of the two salts as indicated by the corresponding letters in tables VII (unbroken line) and VIII (dotted line). 118 BOTANICAL GAZETTE lAUGUST tration employed in the combination. Another interesting case in point may be noted in the experiments of the same investigator on Polyorchis (11), a jelly-fish of San Francisco Bay. In a solution of 50°° NaCl + 6°° MgCl, + 1°° CaCl,, the rhythmical contractions of the margin go on normally, but with a slight increase of CaCl, the contractions are inhibited, and when 5°° of a 3/8 solution of CaCl, are added, they are completely suppressed. On the other hand, when the margin of the fish, containing the sense organs and the central nervous system, is cut off, CaCl, exercises a stimulating action on the isolated center of the fish, and contractions will go on normally; but when MgCl, is added to the solution, in the ratio of 4 parts MgCl, to 1 part CaCl,, the stimulating action of the CaCl, is - suppressed and contractions cease. In both cases, therefore, there is evidence of a definite antagonism between Ca and Mg. Likewise, LILLIE (3) proved the existence of antagonism between the two salts, when he found that the ciliary activity of the larvae of Arenicola would go on normally for some time in a mixture of approximately 4 parts MgCl, to 1 part CaCl,, whereas it would immediately cease if either of the salts at the same concentration was present alone. Again, we find the well-known researches of Loew and his pupils (12, 13), and later the researches of KEARNEY and CAMERON (1); which show in the higher plants the strong antagonism between calcium and magnesium, The last-named investigators found, in their expeti- ments with the white lupin (Lupinus albus) and with alfalfa (Medicago sativa), that when CaCl, was added to MgSO, in about equal propor tions, the plants exhibited about 160 times the tolerance for the latter salt that they did in solutions of MgSO , alone. They found, further, that the antagonism between CaCl, and MgCl,, though not so great (increasing the tolerance about 4o times), was nevertheless very marked, and where CaSO 4 Teplaced CaCl, the antagonism was Very much greater between Ca and Mg than in either of the cases above cited. I wish to cite only one more case, which emphasizes by strong contrast the exceptional results obtained above in experiments with B. subtilis; that is, the results of highly ingenious experiments 0° rabbits and a monkey by MELTzER and AUER (16) showing the antag” nistic effect of calcium on the inhibitory effect of magnesium. As @ PROM TIES PL aE EME Coa” EM SR ES cate Ee Ne ON YD te: Lae neers Pie ae 1909] LIPMAN—EFFECTS OF SALTS ON BACILLUS 119 typical instance may be cited experiment 1 of their series, in which about 13°° of an m/1 solution of MgCl, was injected subcutaneously. Less than half an hour later there was produced general anaesthesia, with all the attending symptoms. When 2°° of a solution of m/8 CaCl, was injected into the ear vein the rabbit was again breathing normally, and when 8°¢ had been given the animal sat up and appeared entirely recovered, except for a stiffness in the hind legs. In these experiments, some of which were even more striking than the one cited, Mettzer and Aver employed, besides the chlorids of Ca and Mg, the acetate and nitrate of the former, and the acetate, nitrate, and sulfate of the latter. The same strong antagonism was noted in all cases. TABLE VIII ALL QUANTITIES GIVEN REFER TO CUBIC CENTIMETERS OF 0.35 ™ SOLUTIONS Culture solution pages gm Miligais Too Mp le hia eas K 4.76 ig — { ie eaieaes a J 4.48 ties es BPE pte A I 4.20 x00 MaCla i 3.78 pt eae Ga G 3.64 foo MgCl Fo r ce So Mel, p 5.08 oa nie: eae D 3-29 Bo MaCh c 343 ote B 3-37 100 CaGhy i ets te A 3-78 In addition to the confirmation of the results stated above in experiments with the same material, one series was also carried out with a culture of B. subtilis obtained from New Jersey, and with salt solutions made up from a different grade of chemically, pure salt. 120 BOTANICAL GAZETTE [avcust | As can be seen from the following table and also from jig. 4, the results fully confirm those above given; and though the absolute amounts are different, the results are relatively the same. It may be of interest to note here that B. subtilis from a 24-hour peptone agar slope was examined in hanging drops of molecular solu- tions of magnesium chlorid and calcium chlorid, and the organisms showed no perceptible ill effects from the action of the solution. The ciliary movements appeared normal even after 24 hours in the hang- ing drop. It was noticed, however, that there was little or no division during the 24 hours and it is likely that the calcium and magnesium salts exercise their toxic effects, partly at least, by inhibiting reproduc- tion, since the ciliary movements seemed to go on without interrup- tion. These remarks, however, are based on too meager experimental evidence to be anything else than conjecture at present, but they serve to indicate a field of most interesting research. Though they are not analogous to the lack of antagonism between Ca and Mg shown above, it is interesting to note two cases on record, in which the addition of one salt to another made a combination more toxic than either. One case is that cited above from OsTWALD’S experiments on the freshwater Gammarus, in which a combination of MgCl, and NaCl in solution was more toxic to that animal than either of these in solution alone. The other case is that noted in the experiments of Kr6énic and Paut (2), who found that the value of mercuric sulfate, acetate, and nitrate as disinfectants was enhanced by the addition of small amounts of the chlorids of the alkalies (K and Na); but, on the other hand, that the addition of the same chlorids to HgCl, reduced considerably the disinfecting powers of the latter. The first instance is not analogous to the results of the writer, because one of the salts used was different, and the experiment was carried out under conditions so totally different that the value of @ comparison is doubtful. In the second instance, as KRONnIG and PAUL themselves suggest in the same article, the increase of toxicity is not necessarily owing to a lack of antagonism between the two salts, but rather to the formation of complex double salts of mercury; which are characteristic of that element, and therefore this agai? cannot be prennetet with the tack of antagonism between Ca and Mg above noted. Tgo9] LIPMAN-—-EFFECTS OF SALTS ON BACILLUS 121 SERIES VIII. SODIUM CHLORID vs. POTASSIUM CHLORID This series was carried out to determine the antagonistic action between KCI and NaCl and was arranged in the same manner as the foregoing series. The ammonia determinations gave the following results: TABLE IX ALL QUANTITIES GIVEN REFER TO CUBIC CENTIMETERS OF 0.35 # SOLUTIONS Culture solution Ret ed ops tepsiesn 5 Miiigrapes Ce FOG Wet ee ae K 10.99 es nc 4 are eee J be te eat CRAs AN eters I 10.50 me Kal ¢ Pe ineaes H Io 08 is Pes eee G 9.66 re eat et tone F a Boa Siar Pe Paiie pours E 17-57 Ras eel eee D Oe a alt pees Cc 13-44 es nat PRI pes B Trial TOG“ RA fe ea A 10.57 That the like valences of the two salts employed do not prevent antagonistic action in the case of B. subtilis (as may have been sur- mised from results in the last series) can be seen from the curve in fig. 5. Here again, there is a marked resemblance between the effect of this combination of metallic salts on B. subtilis and on animals and higher plants. Litutr, for example, showed (3) that the ciliary activity of the larvae of Arenicola, which was inhibited in solutions of either KCI or NaCl alone, went on normally when solutions of the two at the same concentrations were e mixed in the proportion of 20 parts NaCl to 8 parts KCl. ‘ Los (9) and Ostwatp (22) also found, in working on a marine 122 BOTANICAL GAZETTE [AUGUST and a freshwater Gammarus respectively, that a distinct antagonism : exists between NaCl and KCI. Among plants we find that the work — of OsTERHOUT (20) also shows some antagonism between KCI — and NaCl, and here again it is significant to note that there are two maxima. : The curve in jig. 5 shows an unusually g eradual rise and decline. AOme 167729. lkltg | Cm? + Nat/ BST ff C F - ao 57% —Antagonism curve, NaCl vs. KCl. The ordinates at K represent the ammonia phone in milligrams formed in a pure NaCl solution. The o din: ate at ‘ the ordinates at the intermediate points represent the amounts formed in various — combinations of the two salts as indicated by the corresponding letters in table Ix. This is characteristic of the Na and K chlorids used singly, where — they become gradually more and more toxic with the increase of eee md centration. It is consequently in strong contrast to the sharp 4 G of the calcium and magnesium curves, especially that of the former — In this curve, as above noted, there are two maximal points, one ata the combination of 1o0°* of NaCl + 5°¢ KCl, and another at the and — combination of too°¢ KCl + s50°° NaCl. In three confirmatory — series on this experiment, the maximal points were in each cat obtained at the same combinations. Ig09] LIPMAN—EFFECTS OF SALTS ON BACILLUS 123 Discussion Briefly reviewing the results with B. subtilis above given, we note their significance from the scientific as well as the practical stand- point. Of the four chlorids tested singly, NaC] is the only one stimu- lating ammonification at the concentrations employed. It is not unlikely, however, that KCl has a similar effect at a slightly lower concentration. CaCl, is the most toxic of the chlorids used. In this feature, B. subtilis appears to resemble animals, for which calcium is very toxic, and not plants; since for plants, with which bacteria are now classed, calcium is the least toxic of the four chlorids. This fact may have a bearing on the future classification of bacteria. The strong antagonism exhibited in some of the combinations of | salts employed speaks eloquently for the fact that balanced solutions are as necessary for the optimal development of bacteria and allied forms as for the higher plants and animals, a fact which has been denied in a recent publication of LoEw and Aso (13). This is of the greatest practical significance when applied to soil bacteria, and especially those of alkali soils, in which, owing to the excessive amount of one or more salts, the bacterial activity is inhibited, and conse quently plant food is not made available to the higher plants. Because the salts experimented with are all found in our soils’ in larger or smaller amounts, and in some soils are present in excess, it is a matter of practical importance to apply the results of researches on the physiology of plants and bacteria to improve such alkali lands. There is no doubt in my mind that when we have. learned to coordinate the results of researches on plants and soil bacteria, and _ to apply them in the field, we shall have at our command a method E for the control and profitable cultivation of alkali lauds, of which so _ Many thousands of acres are merely vast wastes at the present time. Lastly, the results of these experiments are significant because they open up an unexplored field of bacterial physiology, in which further researches will teach us much. 4 Summary aes ____ 1. Each of the four chlorids (CaCl,, MgCl,, KCI, NaCl) is toxic : for B. subtilis, in the order given, the first being the most toxic and 124 BOTANICAL GAZETTE [avoust the fourth the least. This is quite different from the results with higher plants, where magnesium is the most toxic and calcium the least. 2. A marked antagonism exists between Ca and K, Mg and Nag 1 K and Na. . 3. No antagonism exists between Mg and Ca, but the toxic effect of each is increased by addition of the other to it. This is just the E opposite of what has hitherto been found for plants. In conclusion, the writer desires to express his indebtedness to — Prof. W. J. V. OsTeRHOUT, at whose instance these researches were — begun, for helpful suggestions and kindly criticism throughout the 5 course of the investigations. 4 _ LABORATORY OF SorL BACTERIOLOGY UNIVERSITY OF CALIFORNIA LITERATURE CITED 1. KEARNEY AND CAMERON, U. S. Dept. Agric. Report no. 71. Pavt, T., Die chemischen Grundlagen der a von der 2: OnIG, B., Giftwirkung und ashusckiten’ Zeits. Hyg. Inf.-Krankh. 25:59. 1897- 3. Liu, R., On differences in the effects of various salt solutions 00 ciliary and: muscular movements in Arenicola larvae. Am. Jour. Physiol. 5:56-85. 1901. 4. Lipman, J. G., Reports of the soil chemist and bacteriologist. Repts. N. Je Agric. Exp. Sta. 1906, 1907. 5. Lorn, J., Ueber die Bedeutung der Ca- und K-Ionen fiir die Herahitigkt Pfliiger’s Archiv 80: 229-232. 1900 6. , On ion-proteid ncknpoaads. etc. I. Am. Jour. Physiol. 3: sara 1900. , On the different effects of ions, etc. Am. Jour. Physiol. 4:383-390 1900. , Studies on the oe. _ of the valency, etc., of ion: I. Am. Jour. Physiol. 6: 411-433. , Ueber die relative Giftigkeit v yon desire Wasser, zuckerliu gen, etc. Pfliiger’s Archiv 97: 394-409. 3. ; 10. ———, Studies in general physiology 2: os 715; ha. 905- a 11. ———, The stimulating and inhibitory effects of M ood Ca upon he rhythmical contractions of a jelly fish (Polyorchis). Jour. Biol. Chem- 1:427-436. 1906. 12, Loew, O., U. S. Dept. Agric. Bur. Pl. Ind. Bull. 45. : a 13. LoEw AnD Aso, On pees balanced solutions. Bull. Coll. ae : Imp. Univ. Tokyo 7:no a iS LY Se ERO RAIS he Ae Me ea FT) Oe ae er Reon ON we omy Sree Bircae FRM EP Coe eee eee 1909] LIPMAN—EFFECTS OF SALTS ON BACILLUS 125 . MAcowan, FLorENcE N., The toxic effect of certain common salts of the soil on plants. Bor. GAZETTE 45:45- 49. 908. 5. Marcuat, E., Bull. Acad. Roy. Sci. Belg. ‘TIL 25:727. 1893. » MELrzeEr, S. t AND AUER, J., The antagonistic action of calcium upon ‘the inhibitory effect of magnesium. Am. Jour. Physiol. 21: 403. » OsterHouT, W. J. V., On the importance of physiologically St solu- tions for plants. Bor. GAZETTE 42: 127-134. 1906. , Extreme toxicity of sodium chloride and its prevention by other salts. Jour. Biol. Chem. 1: 363-369. 1906. » Die Schutzwirkung ah Natriums fiir Pflanzen. Jahrb. Wiss. Bot. 46: rie figs. 3. 1900. , On similarity in the behavior of sodium and potassium. Bor. Gir 48: 98-104. 9. - OsTWALD, W., Univ. pate Publ. Physiol. 2: 163-191. 1905. 5. Ve shucks iiber die Giftigkeit des Seewassers fiir Siisswassertiere (Gamiliens pulex De Geer). Pfliiger’s Archiv 106: 568-598. pls. 2-7. 1905. ANN, E., Bodenkunde 117. Berlin. 1905. THE GAMETOPHYTES OF CALOPOGON EULA PACE (WITH PLATES VII-IXx) Photolith plates 2nd edition a This paper reports a continuation of the work on certain orchids — begun in 1906. The peculiarities in the development of the mega- 4 spores, and in the number and origin of the nuclei in the embryo sac . found in Cypripedium (14) made it seem desirable to continue the — investigation. 4 The same methods were used as in the work on Cypripedium. — The material of Calopogon pulchellus R. Br. was collected near 4 Chicago in the summer of 1906. The usual chromacetic and alcohol: — formalin solutions were carried to the field and the material was — killed as collected. The greater part of it has been cut in serial sec- tions five to seven microns thick, and stained in safranin and gentian violet. MEGASPORES The ovules are very numerous and even smaller than those of : Cypripedium, the mother cell being five to ten microns in diametel. — The archesporium does not seem to be differentiated early. Fig. 1 shows an ovule pretty well advanced, and yet it is not possible to 3 distinguish an archesporial cell by any difference in staining. The — one drawn shows the greatest difference in size in favor of the usual ig archesporial cell, but other ovules in the same ovary show the other cells of the axial row to be larger; so here also it is probably the cell : that is approaching mitosis that is larger. Fig. 2 is taken from another ovary in which the ovules are apparently in the same stage as in fig. 1. This one suggests a more advanced stage by the broaden” ing of the ovule. Yet this may be related to the appearance of more — than the one mother cell, for these ovules with two sporogenous cells are broader, as will be seen later. The first undoubted archesporiu™ seen was in the stage shown in fig. 3. Here the ovule is much larger than in the first two figures and the first integument is beginning. In this ovary more than half of the ovules were in this stage, the arche- sporial cell being large and showing difference in staining reaction Botanical Gazette, vol. 48] [x26 has ee ped ee eae eet p> 1909] PACE—GAMETOPHYTES OF CALOPOGON 127 The other ovules were in the mother cell stage (fig. 4). The integu- ment is only a trifle niore advanced in the latter than in the former, but the nuclei are in all stages of synapsis. The archesporial cell may become the mother cell without division, and no parietal cell was ever found. But it is possible that in some cases it divides; for an archesporium of more than one cell was rare, being found only once (fig. 26), and yet several ovules with two mother cells in position to have been formed by division of a single archesporial cell were found (figs. 27, 29). It is evident that these must have originated by a division of the archesporial cell, or the archesporium must have consisted of two cells. A more remarkable case still is that in which two distinct sporo- genous areas are differentiated in the same ovule (figs. 28-31). Fig. 31 shows several cells of nucellar tissue between the two mother cells, the cut being across the ovule in a different direction from that of jig. 28. A somewhat later stage, similar to fig. 28, is shown in fig. 30. Fig. 32 shows at least one of the mother cells divided, and one of the resulting daughter cells increasing for the second division, the other disintegrating in the usual fashion. The presence of more than one mother cell is not rare in my material. Of about sixty ovaries cut, thirteen showed ovules with two mother cells, or stages derived from this condition. In these thirteen ovaries, the ovules showing this con- dition vary from one to seven, giving a total of thirty-seven. Of these thirty-seven, twenty-one are similar to figs. 28 and 37, and sixteen resemble jigs. 27 and 29. There was in all probability double this number, for only those were counted in which both cells appeared in the same section. No attempt was made to trace the ovules from section to section for this condition, and it is evident that there are more chances against getting both in the same section than in favor ofit. Fig. 3risa drawing from a single section, but the whole ovule was traced carefully from section to section for evidence of the coales- cence of two ovules. The only abnormal appearance was the unusu- ally broad funiculus. Fig. 33 shows the megaspores derived from the two adjacent mother cells. In each case the chalazal megaspore is developing and the other three are disintegrating. In the lower or micropylar group the megaspores are in a row—the usual row of four, except that the wall is lacking between the two upper megaspore 128 BOTANICAL GAZETTE [Aucust nuclei. In the upper or chalazal group two of them lie side by side without a separating wall. The upper two are in the normal position, but the usual separating wall is lacking. Fig. 34 seems to show an embryo sac of two nuclei derived from the chalazal group of two mother cells. The three disintegrating nuclei are probably mega- spore nuclei, and the micropylar mother cell has not divided. Fig. 35 is taken from a much younger ovule, but a very broad one. It seems to be the product of two sporogenous cells, the chalazal mother cell having divided to form the two daughter nuclei, the micropylar mother cell being still in metaphase. It is possible that this is the result of the second division of the chalazal daughter cell without walls separating the two megaspore nuclei, the micropylar daughter cell being still in mitosis. But the chromosomes in this nucleus give every appearance of the heterotypic division, and the ovule is so un- usual in appearance that it seems to have had two mother cells. Synapsis continues for some time, if the extent of development of the integument be considered proof (figs. 4, 5). The division of the mother cell takes place in the usual way (figs. 5-10), giving the two daughter cells (jig. 17). The number of chromosomes is appar ently thirteen (fig. 6), although only a few counts were made, but this one seemed unusually distinct, so it is probably the correct num- ber. Several counts were attempted in a sporophytic area, giving approximately twenty-six. It is probable that sometimes the wall separating the daughter nuclei fails to appear. Fig. 9 would be expected to show some evidence of wall formation, if it were going to appear. Fig. 15 shows the division completed, with no suggestion of a wall. Fig. 16 gives no wall. Several examples of this failure of the wall were found, and in others it seemed very faint and probably disappeared. In many plants the chalazal daughter cell divides; but in Cale- pogon it seems quite common for both to divide, although the micro pylar cell is even then somewhat smaller than the chalazal cell (figs 13, 14). These divisions may occur at the same time as in the above figures, or either may precede the other. Figs. 17 and 18 show the chalazal cell dividing first, the former showing the micropylat cell somewhat more advanced than the latter. In jig. 19 the micropylat daughter cell has almost completed the division, while the chal ST eS eer aa eT Ee eee a 1909] | PACE—GAMETOPHYTES OF CALOPOGON 129 cell is still in the spirem stage. This does not appear so often as the other in my material. At this division of the daughter cells the walls begin to form in the usual way (figs. 14, 18, 19), though in a few instances no evidence of wall formation was seen (figs. 17, 20). But the walls all disappear, if they were ever found in these cells (jigs. 20, 28), for no case of a wall at this stage was seen, though hundreds of examples like those figured were found. After this division the micropylar nucleus from the inner daughter cell begins to disintegrate (jigs. 21, 22), although it may sometimes divide (fig. 24). Fig. 23 shows both daughter cells divided, with one megaspore nucleus in each case disintegrating. While apparently two of the megaspores are active, one of them is already in advance of the other, judging by size of nucleus and cell. Fig. 24 shows the micropylar daughter cell with the nucleus in metaphase, while jig. 25 is’only late spirem. Probably the former would have completed the division. Figs. 24 and 25 are also interesting as the only cases seen in which the mega- spore nucleus that usually disintegrates in the sac shows evidence of further development. In the first it has divided, while in the second it is in the spirem stage, yet in both cases it is evidently disintegrat- ing. The megaspore that is to form the sac in fig. 25 is in mitosis with the spindle well formed. EMBRYO SAC As the walls disappear, or never develop, in the division of the daughter cells, the two megaspore nuclei are left in the embryo sac. The micropylar nucleus apparently always disintegrates, as does the cytoplasm about this nucleus (figs. 21, 22, 23, 48). This leaves only one megaspore nucleus, probably one might say only one megaspore, to enter into the organization of the embryo sac. This nucleus divides, giving a sac with two nuclei (jig. 46). The three other bodies in the sac are probably the three disintegrating megaspore nuclei. The two nuclei of the sac divide simultaneously (fig. 47), giving a four-nucleate sac (fig. 48). This figure is interesting be- Cause the three disintegrating megaspore nuclei are easily identified - at this late stage. Fig. 49 shows about the same stage, except that the sac has increased in size and the nuclei are preparing for the ae ee division, although there are still traces of the spindles of the preceding 130 BOTANICAL GAZETTE [avcusT — mitosis. These spindles show no traces of wall formation. The — micropylar daughter cell did not divide here, although the nucleus — completed the prophase, even forming the chromosomes. There is — just a trace of the disintegrating megaspore nucleus in the sac. The — four nuclei in the sac increase in size and divide in the usual fashion ~ (fig. 50). The two dark bodies in the lower part of this sac are prob- ably the remains of the micropylar daughter cell and the disintegrating megaspore nucleus. This division gives eight nuclei in the sac (jig. - 51). By comparing figs. 51 and 52 it can be seen that one of the four nuclei at the lower end passes up toward the center, and the sister to the egg moves down in the usual position for the two polar — nuclei. The eight nuclei arrange themselves in the usual way—an egg apparatus of two synergids and the egg in the micropylar end of the sac, three antipodals in the chalazal end, and the two polars near the center (figs. 52, 53). Fig. 53 shows a_ pollen tube already forcing its way between the integuments, about half- way to the sac. MICROSPORES AND MALE GAMETOPHYTE The pollen in Calopogon is in masses or pollinia, as it is in many of the orchids. Each massula is apparently the group of cells result- ing from the division of each sporogenous cell (jig. 36). The whole sporogenous area probably reaches the mother cell stage at the same time (fig. 37). The mother cells divide in the usual way, by the so-called simultaneous division, which is thought to be more characteristic of dicotyledons than of monocotyledons, although found in both group> (COULTER and CHAMBERLAIN 7, p. 121). This gives the tetrad form in some cases, but in others the four spores lie in any plane (jigs. 38-42): The microspore nucleus divides into the tube and generative nuclel while the pollen is still in the sac (fig. 43). Pollen tubes are numerous in the ovary, in some cases at least, when ovules are still in the mother cell stage, like jig. 5, although no pollen tube was ever seen in contact with an ovule at this stage. Figs. 4r and 42 are examples of pollen ‘tubes within the ovary, before entering the ovules. In these the ge erative nucleus had already divided into the two male nuclei, 5° it is probable that this division takes place when the pollen grain 8% minates. ; 1909] PACE—GAMETOPHYTES OF CALOPOGON 131 FERTILIZATION As has been said, the embryo sac when ready for fertilization con- tains eight nuclei, arranged in the usual fashion—the egg apparatus of two synergids and an egg in the micropylar end, three antipodals at the opposite end, and the two polars about the center of the sac (jig. 53). When the pollen tube is entering the sac, the egg and the polar nuclei may be in late spirem stage (fig. 54). In fig. 55 the two polars have already formed chromosomes. Fig. 56 shows the fusion of a male nucleus with the egg, and the triple fusion in the center of the sac is undoubtedly that of the two polars and the second male nu- cleus. Not very much material was examined at this stage. But in all that was seen there was every indication that this is the usual condition. DISCUSSION Sporogenous cells—BowER (3) states that a multicellular arche- sporium is found in several of the archichlamydeous dicotyledons, especially in Amentiferae, Rananculaceae, Rosaceae; but that it is apparently rare in more advanced dicotyledons and in the monocoty- ledons. GuIGNarD (g) reports Ornithogalum pyrenaicum with an archesporium of two cells, only one of which gets beyond the arche- Sporial stage. BARNARD (1) reports two embryo sacs in Lilium can- didum. CouLTER and CHAMBERLAIN (7, p. 61) say that they have seen one preparation of Lilium philadelphicum with three archesporial cells and another with five; but no figures are given. FERGUSON (8) in a note figures two mother cells in Lilium longiflorum with intervening nucellar tissue. But, as has already been shown, there are many such cases in Calopogon, thirty-seven cases of two mother cells or stages evidently derived from them being seen, in thirteen ovaries out of about sixty cut, and this probably represents less than half the number actually present. So while this condition is very far from being the usual one in my material, it could hardly be called rare, and therefore abnormal. It seems best to regard it as a primitive character that has been retained, or at least not entirely eliminated. SARGANT (1) and others hold that monocotyledons are derived from dicotyledons. This occasional appearance of a multicellular arche- sporium may indicate that the dicotyledons from which these came 132 BOTANICAL GAZETTE [AUGUST still had a multicellular archesporium, as the more primitive dicoty- ledons do yet. Megaspores.—There are usually four megaspore nuclei formed. However, in a few instances, only one daughter cell divided. In many cases the wall separating these megaspore nuclei at the second division was seen to be forming (figs. 14, 16, 19) but always it had disappeared at maturity (figs. 20, 23). In a few cases there was no indication of a wall forming (jigs. 15, 17,20). This omission of all cell formation in the second division is the condition found in Cypripedium (14). The fact that Calopogon usually has the four megaspore nuclei was rather unexpected in this highly specialized group of the mono- cotyledons. For the tendency is not only to a row of three, due to the failure of one of the daughter nuclei to divide, but to the condition known as the mother cell functioning as a megaspore (COULTER and CHAMBERLAIN 7, p. 80), which is common in monocotyledons. SCHNIEWIND-THIEs (16) has shown that in Lilium the heterotypic division takes place within the embryo sac, only ephemeral walls. being formed in either of the divisions from the mother cell to the megaspore. In Cypripedium it was found (14) that no wall appeared at the second division, and that two megaspore nuclei are used in forming the embryo sac. CouLTEr has shown (6) that this may be a very important point in connection with embryo sacs of more than eight nuclei. For if more than one megaspore nucleus enters into the organization of the sac, it is evident that more than eight nuclei in the sac would be the result of the usual five divisions from mother cell to egg found in angiosperms. So that while Cypripedium with its four-nucleate sac seems more reduced than Lilium, it really has just the same number of divisions from mother cell to egg (14). BRowN (4) objects to calling these nuclei in Cypripedium meg spore nuclei, yet he proceeds to do it in Peperomia, although there is only the additional evidence of ephemeral walls. JOHNSON (11) has also shown these four nuclei in the tetrad position in Peperomia. The origin of the nuclei is identical in both Cypripedium and Peper mia, with the usual megaspore story except in the matter of wall—4 mother cell passing from synapsis through the heterotypic and homo typic divisions. In Cypripedium a permanent wall appears at the heterotypic division, but none at all at the homotypic; in Peperomia a te eee ae A: Sa ee ee Ne er WAT Re ee ee ~The s 1909] PACE—GAMETOPHYTES OF CALOPOGON 133 ephemeral walls appear at both divisions. This gives apparently four megaspore nuclei forming the sac in Peperomia, while only two enter into its organization in Cypripedium. It might be better to select another name for these nuclei, but it would always involve the explanation of their similarity to megaspore nuclei, with apparently no gain in clearness. For our notion of spores, extending back through pteridophytes and bryophytes, is that when a mother cell divides there are four spores produced, the spore being the cell formed by the heterotypic and homotypic divisions. The matter of walls would not seem to be so important as the behavior of the nuclear mate- vials; for all sorts of variation in the kinds and shapes of these are found, these differences being related apparently to the environment of the spore. The egg is of course a descendant of only one mega- spore, however many may enter into the construction of the sac. And it seems to involve less change from what have seemed to be the essen- tials to regard these as megaspore nuclei than to conceive of a mother cell functioning directly as a megaspore and yet proceeding to the very same heterotypic and homotypic divisions. This is more evident still when Calopogon is taken into consideration, as it seems to present a stage that might be considered intermediate between Cypripedium and the usual one. For here there are certainly two megaspore nuclei in the sac, one finally disintegrating, although some evidence of its division is present in two cases examined (figs. 24, 25) This lack of walls is not very rare. Lxoyp (12) reports them as usually absent in Rubiaceae, although the tetrad is formed. Here only one megaspore nucleus functions. The same condition is reported by CANNON (5) in Avena, and by SMITH (17) in Eichhornia. WIEGAND (19) finds the second divisions unaccompanied by walls in Potamogeton foliosus, and HOLFERTY (10) finds the wall omitted in the division of the micropylar daughter cell in Potamogeton natans. BILLINGs (2) reports one case of megaspores without separating walls in Tillandsia usneoides. And the many cases where the mother cell is said to function as a megaspore seem to represent the same con- dition, except that the non-functioning megaspores not only do not disintegrate but even divide and thus contribute to the contents of the embryo sac. . In Calopogon only one megaspore nucleus is used in forming 134 BOTANICAL GAZETTE [AUGUST the sac, though two are certainly in it (jigs. 21, 22), just as in Cypripe- dium. Both may divide, though no evidence beyond a late spirem or metaphase stage was seen, except in one case (fig. 24), and here the usual disintegration was taking place. So in this respect Calopogon might be regarded as suggesting what may have taken place in the ancestry of Cypripedium, as it passed from the usual tetrad or row of three to its present condition. Fertilization.—So-called double fertilization is present here as in Cypripedium. It will be remembered that NAWwaAscHIN (13) reports it lacking in certain tropical orchids, while STRASBURGER (18) found it in orchids he investigated. SUMMARY 1. There is usually one sporogenous cell which becomes the mother cell. But in many cases two mother cells are found, either contigu- ous or with nucellar tissue between. 2. Four megaspore nuclei are usually formed; occasionally the micropylar daughter cells in the second division either never appear or are ephemeral. This leaves two megaspore nuclei in the sac. But three of these megaspore nuclei disintegrate, the two from the micropylar daughter cell and the micropylar one in the sac. 3. The embryo sac is the usual eight-nucleate kind, developed in the usual way. 4. Pollinia are in massulae in four loculi. Tetrads are in any position, but there is no rounding-up of pollen grains. Tube and generative nuclei are formed before the pollen escapes. The pollen tube shows a tube nucleus and two male nuclei as it enters the ovary: 5. Double fertilization occurs. BAYLoR UNIVERSITY Waco, TEexas Y LITERATURE CITED 1.. BARNARD, C. H., Recherch les sph Saag Jour. Botanique 14: 118-124, 177-188, 206-212. pls. 4, 5. 1900. - Briincs, F. H., A study of Tillandsia usnevides. Bot. GAZETTE 38:99 121. pls. 8, 9. 1905. - Bower, F. O., The origin of a land flora 97. 1908. - Brown, W. H., The nature of the embryo sac of Peperomia. Bort. GazETIE 46: 445-460. pls. 31-33. 1908. : N > w Fee Sy) Mk, eee hez Lilium candidum. — Ane 2 ‘ol aie ie a 1909] PACE—GAMETOPHYTES OF CALOPOGON 135 5. Cannon, W. A., A morphological study of the flower and embryo of the wild oat, Avena fatua. Proc. Calif. Acad. Sci. III. 1: 329-364. pls. 49-53. 1900. - COULTER, J. M., Relation of megaspores to embryo sacs in angiosperms. Bot. GAzETTE 45:361-368. 190 COULTER AND CHAMBERLAIN, Morphology of angiosperms 80. 1903. - Fercuson, M. C., Two embryo sacs in Lilium longiflorum. Bot. GAZETTE 43:418, 419. fig. 2. 1908. - Guicnarp, L., Recherches sur le sac embryonnaire des phanérogames angio- spermes. x Sci. Nat. Bot. VI. 13:136-199. pls. 3-7. 1882. to. Hotrerty, G. M., Ovule and embryo of Potamogeton natans. Bor. GAZETTE 31:339-346. pls. 2, 3. 1901. 11. JOHNsoN, D. S., A new type of a sac in Peperomia. Johns Hopkins University Cicatas 195:19-21. pis. 1907. 12. Luoyn, , The So enbeao of Rubiaceae. Mem. Torr. Bot. Club 8: ea pls. 8-15 13. NAWASCHIN, S. ne Beluditess bei den Orchideen. Ber. Deutsch. Bot. Gesells. si 224-2 1. 9. Igoo. 14. Pace, L., Fevtilisation in Cypripedium. Bot. GAZETTE 44:353-374- Pls. 24-27. 1907. 15. SARGANT, E., The reconstruction of a race of primitive angiosperms. Annals of Botany 22:121-186. figs. 1-21. 1908. 16. SCHNIEWIND-TurEs, J., Die Reduktion der Chromosomenzahl und die ihr folgenden Kernteilungen in den Embryosack-Mutterzellen der Angiospermen. Jena. 1901. 17. Suir, R. W., A contribution to the life- eee of the Pontederiaceae. Bor. GAZETTE 25: 324-337. pls. 19, 20. 1808. - STRASBURGER, E., Einige Bemerkungen zur Frage nach der doppelten Befruchtung bei den Angiospermen. Bot. Zeit. 58:290-316. 1900. - Wrecanp, K. M. , The development of the embryo sac in some monocotyle- donous plants. Bos. GAZETTE 30:25-47. pls. 6, 7. 1900. EXPLANATION OF PLATES VII-IX All figures were drawn with a Bausch and Lomb camera. Fig. 8 was made with Leitz no, 4 ocular and no. 7 objective, and fig. 36 with no. 2 ocular and no. 7 objective; all others with Leitz no. 4 ocular and Bausch and Lomb 7x objective. The abbreviations used are as follows: c chalazal daughter cell and nucleus; ° €88; § generative nucleus; gc generative cell; m micropylar daughter nucleus; = Ragga nucleus; polar nucleus; s synergid; ¢ tube nucleus; 3 male nucleus an oN © al oO i © PLATE VII Fic. 1 -—Young ovule. Fic. 2 -—Young ovule with broader funiculus Fis. 3. —Archesporial cell differentiated; beginning of the integument. FIG. 4.—Mother cell; synapsis almost complete. 136 BOTANICAL GAZETTE [AUGUST Fic. 5.—Synaptic knot complete; integument much older. Fic. 6.—Metaphase; thirteen chromosomes; — spindle. Fic. 7.—Spindle for division of mother cell. Fic. 8.—Mother cell in same stages as fig. 7, but integuments much farther advanced. Fic. 9.—Late anaphase; no evidence of wall formation. Fic. 1o.—Late telophase; wall separating the daughter nuclei. Fic. 11.—Two daughter cells Fic. 12.—Two daughter cells, one of which is disintegrating. Fic. 13.—Two daughter cells in mitosi Fic. 14.—Two daughter cells in telophase with walls forming; these are the 4 megaspores. Fic. 15.—Two daughter nuclei with no wall separating them; traces of the spindle still present. Fic. 16.—Two daughter nuclei with no separating wall, but one of them larger than the other. Fic. 17—Chalazal daughter cell in telophase, with no trace of wall; micro- pylar daughter cell with chromosomes formed for division. Fic. 18.—Chalazal daughter cell in telophase, with beginning of wall forma- tion; micropylar daughter cell shows a slight thickening of the spirem. PLATE VIII Fic. 19.—Chalazal daughter cell in prophase; — short and thick; micro- pylar daughter cell in late telophase with wall forming. IG. 20.—Two megaspore nuclei of equal size; micropylar daughter cell undivided. Fic. 21.—Embryo sac beginning to increase in size; one megaspore nucleus beginning to show evidence of mitosis; another megaspore nucleus disintegrating within the sac; the two megaspore nuclei from the micropylar daughter cell also csntegratng, with slight traces of the a still present. Fic. 22.—About the same stage as fig. FIG. 23. aac megaspore nuclei, one ra each of the ‘Sane cells disin- tegrating with its own cytoplasm, the other one in each case in good condition for development, although the chalazal nucleus is the larger. Fic. 24.—Micropylar daughter cell with chromosomes formed for mitosis; one megaspore nucleus in sac developing, the other already divided, and both nuclei disintegrating. Fic. 25.—Chalazal megaspore nucleus with spindle; the other megaspor’ nucleus in the sac in late spirem, or metaphase; the micropylar daughter - nucleus in spirem stage. Fic. 26.—T wo sporogenous cells in one ovule. Fic. 27.—Two mother cells in one ovule. Fic. 28.—Two mother cells with nucellar tissue between them. Fic. 29.—Two mother cells Nieeeaceie wn tay Fars oak. ly ooo ar ath Be Sol RS Aly vie oi > Be Sy hey N S 3 TATE. ag LA! Lae ses AL GAZETTE, XIViI Ye eee aaa, 1 ee aS) ee a ee Oe. ea. kee ed Oi 1909] PACE—GAMETOPHYTES OF CALOPOGON 137 Fic. 30.—Two mother cells after recovery from synapsis. Fic. 31.—Two mother cells with several cells of nucellar tissue between; ovule cut across. Fic. 32.—Ovule with two daughter cells; and probably another mother cell r it, or another daughter cell with slight traces of the second disintegrating. — —Eight megaspores from two mother cells. —Two-celled embryo sac, three disintegrating megaspore nuclei, and a sede cal recovered from synapsis. G. 35.—One mother cell in ee the other already divided, giving two ee nuclei without separating wa PLATE IX Fic. 36.—Diagram of anther, showing four pollen masses; massulae shaded. Fic. 37.—Pollen mother cells in synapsis. Frc. 38.—Pollen mother cell with spindle. Fic. 39.—Pollen mother cell in telophase. Fic. 40.—Telophase of second division. + Fics. 41, 42.—Pollen tetrad; microspore nuclei. : IG. 43.—Two tetrads, each pollen grain of which shows tube and generative nucleus. Fic. 44.—Pollen tube from within ovary. Fic. 45.—Pollen tube near ovule. Fic. 46.—Two-celled embryo sac. Fic. 47.—Both nuclei in sac in mitos Fic. 48.—Four-celled embryo sa ae disintegrating megaspores Fic. 49.—Four-celled sac; traces a spindle of preceding division; megaspore nucleus within sac disintegrating. Fic. 50.—Four-celled sac; prophase for next division; traces of disintegrating megaspore nucleus and micropylar daughter ce Fic. 51.—Eight-celled sac; traces of spiniding of preceding division. Fic. 52.—Nuclei beginning to assume usual position in sac. Fic. 53.—Sac ready for fertilization; egg apparatus of egg and two synergids; two polars, one a sister to the egg; three antipodals; pollen tube between integuments. Fic. 54.—Pollen tube within the sac; egg and two polars in late < = metaphase. Fic. 55.—Pollen tube in sac; egg with thick spirem; polars with chromosomes. Fic. 56.—Double fertilization. ON MESARCH STRUCTURE IN LYCOPODIUM" EDMUND W. SINNOTT (WITH PLATE xX) Halftone The position of the protoxylem in relation to the later-formed elements of the wood has been the subject of careful investigation in the various groups of vascular plants, both fossil and living, and has often been brought forward as evidence of the relationship of one group to another. In his description of the anatomy of a specimen of Sigillaria, in 1839, BRONGNIART (1) showed the central cylinder to be formed of a ring of vascular bundles, each composed of an inner, primary part, and an outer, secondary part, the latter characterized by the radial arrangement of its elements. The small spiral elements lie on the outer edge of the primary wood, which was all developed in a cen- tripetal direction, while the secondary wood grew centrifugally. The protoxylem is thus surrounded by later-formed elements. In his classic work on the anatomy of the cycads, METTENIUS (2), in 1861, described the structure of the vascular bundle in the petiole and blade of certain living cycads. He showed that in the leaf-trac¢, as it leaves the cylinder of the stem, the protoxylem is all on the inside of the later-formed, mostly secondary, wood, but that as the bundle ascends into the petiole, the later-formed wood gradually bends around inwardly and incloses the spiral elements. Finally the ce™ trifugal wood, which is probably all secondary, is greatly reduced, and separated from the protoxylem by parenchyma, while the ce™ tripetal wood forms the bulk of the bundle, and bears at its outer most point the cluster of spiral tracheids. METTENIUS (2, P- 582) noticed the resemblance between this bundle and one of the ste™ bundles of Sigillaria, and remarks that the much greater development of centrifugal secondary wood in the latter is due to the fact that belongs to the vascular system of the stem. ‘ RENAULT (3), however, was the first to really suggest the aflim'y ii sen wise from the Phanerogamic Laboratories of Harvard University, no. 10, Botanical Gazette, vol. 48] ; (138 4 1909} SINNOTT—MESARCH STRUCTURE IN LYCOPODIUM 139 _ of the cycads with the Sigillariae on the basis of a common possession of this character. He carefully distinguished the irregularly arranged — _ centripetal wood from the radially disposed centrifugal wood of the _ sigillarian bundle, and was the first to describe the structure of the _ leaf-trace in this genus. The elements in the leaf are also formed in _ two directions, those on the outside often being radially arranged. This _ structure making the comparison with the cycads still closer, RENAULT comes to the conclusion (3, p. 281) that “les Cycadées actuelles qui 4 possédent dans la structure du cordon foliaire cette analogie si frap- 9 pante avec certaines plantes houilléres, n’en sont que les représentants _ amoindris et en voie de décadence.”’ _ _Renautrt has applied the term diploxylic to bundles possessing q centrifugal as well as centripetal wood, and has grouped together _ Sigillaria and Poroxylon under the head DreLoxyiéEs. Count 4 Sotms-LAUBACH (4, p. 263), however, called attention to the fact that _ where all the centrifugal wood is secondary, the original primary _ bundle, which thus has its oldest elements on the very outside, is of a _ different type from one where there is primary wood on the outside, _ as well as on the inside, of the protoxylem. For the former type of _ primary bundle he suggested the name exarch, and for the latter type _ Mesarch, terms which have since been in current use with those mean- _ ings. RENAULT’s diploxylic implies the presence of secondary wood. __ On the characteristic possession of one of these two main types of q primary bundle, modern writers have often divided living and fossil g vascular cryptogams into two great groups—the Fern series generally, 3 as typically mesarch, and the Lycopodiales, fossil and living, as __ typically exarch. ___ This general rule, however, does not hold at all closely. Among ’ living ferns, there are numerous instances of exarch structure, for a example in the stem of Trichomanes scandens, of Lygodium dicho- _tomum, and of Loxoma Cunninghamii. The same holds true of fossil ferns and their allies. Zygopteris shows both internal and ex- _ ternal protoxylem, while Megaloxylon is clearly exarch. _ Among the typically exarch forms, on the other hand, RENAULT (3) has figured mesarch leaf-traces in the Sigillariae. They are also found in certain species of Lepidodendron. Numerous cases of such _ development also occur in the modern relatives of this group. In 140 BOTANICAL GAZETTE [avcust 4 the center of each stem bundle of Tmesipteris there is a cluster of — initial elements, the breaking-down of which often results in the i formation of a lacuna. Although the cylinder of the stem of Selagi- — nella is characteristically exarch, Greson (5) has noted, in the case — of the protostelic $. spinosa, that in the trailing portion of the stem, — all the protoxylem is in the center of the cylinder, completely inclosed by metaxylem. The root in the whole genus is also distinctly mesarch. In Phylloglossum, it is well known that the tubular stele at the base of the peduncle, the ring of bundles into which this — divides higher up, and the traces of the sporophylls, have their first-formed wood elements surrounded on all sides by later q ones. Exarch development seems entirely lacking, both in this — genus and in Tmesipteris. 3 4 In Lycopodium, however, precisely the reverse seems at first ; ‘sight to be true, and I have been unable to find a recorded instance — of the occurrence of mesarch development in the genus. In an endeavor to determine the presence or absence of such a char- acter, the following species and varieties of Lycopodium were investi- gated: L. inundatum L., and var. Bigelovii Tuckerm.; L. lucidulum Michx.; L. annotinum L.; L. obscurum L.; L. tristachyum Pursh; — L. complanatum L. var. flabelliforme Fernald; and L. clavatum L. L. inundatum and its variety are somewhat delicate forms, and have by far the most poorly developed vascular system of the species looked at. In both, the xylem rays are few in number (3-6); and along the much broadened end of each extends a row of crush protoxylem elements. There is no indication of metaxylem outside of these. In the leaf-trace, however, especially at a little distance from the cylinder, the smaller elements, ringed or loosely spiral, ten¢ to become clustered at the center of the bundle. Just before the a trace enters the leaf, these elements break down, leaving a protoxylem 2 lacuna, completely surrounded by later-formed, closely spiral ele- = ments. This is perfectly evident in both transverse and radial sec tions (figs. 1, 2). In the case of L. lucidulum, the central cylinder is also small, 1 comparison to the diameter of the stem, and its xylem rays are few in number and broadened at the ends. As in L. inundatum, howeVv — there is no indication of centrifugal wood in the cylinder itself, but ea ng eee ee te ES iy PEM ed an iy Oe eee ae ee 1909] SINNOTT—MESARCH STRUCTURE IN LYCOPODIUM I4I leaf-traces, though composed of a comparatively small number of cells, show in nearly every case a mesarch structure (jig. 3). The remaining species studied have much better developed vascu- lar tissues. Their cylinders are in general very similar, being com- posed of a much larger number of xylem rays, which end more or less acutely. In all the species, metaxylem cells occur just outside the protoxylem of the cylinder. In L. éristachyum and L. com- planatum var. flabelliforme, this mesarch development is not common, but in L. obscurum and L. clavatum, especially the latter, it is very noticeable. In vertical section, the centrifugal elements are seen to be reticulate, not scalariform, as in the rest of the metaxylem (figs. 4,6). The exceptional development of this structure in L. clavatum may be due to the fact that its vegetative growth is more luxuriant than that of any of the other species studied. In all these forms, the leaf-trace again is very clearly mesarch (figs. 7-9). ‘This is especially conspicuous, perhaps, in L.: tristachyum and L. complanatum vat. flabelliforme, where a large protoxylem lacuna occurs in the center of the trace (fig. 9). In all the species, the leaf-trace, as it leaves the cylinder, is very small, but rapidly increases in size in the cortex, where it possibly serves to store water. The development of the protoxylem of the central cylinder is always from without inward. The single row of centrifugal metaxy- lem elements occurs directly outside the earliest-formed xylem cells. Sections through the growing-point of L. clavatum showed that the metaxylem elements on both sides of the protoxylem developed nearly simultaneously. In the leaf-trace, also, as was shown by a very young stem of L. complanatum var. flabelliforme, the elements sut- rounding the protoxylem are all developed at the same time. The leaf-trace of Selaginella rupestris (L.) Spring was investigated, and though composed of a very small number of cells, it showed 4 strong tendency toward mesarch arrangement. It is interesting to Rote here an observation of Gipson (6, p. 151) on the leaf bundle of Selaginella. “In the upper third of the leaf the protoxylem ae ments become accompanied by several short reticulate tracheides which flank the spiral tracheides, and in section (e. g., of S. Braumit) May inclose the spiral elements completely.” ' 142 BOTANICAL GAZETTE [aveust It is noteworthy that in certain of the fossil Lycopodiales, as above “mentioned, there is clear evidence of the possession of mesarch struc- ture in the primary wood of the leaf-trace. 3 That there is no sharp line of cleavage between mesarch and exarch 4 vascular cryptogams is thus perfectly clear. Among the main groups, — we have numerous instances of both types of development, and the 4 one merges, little by little, into the other. In Lycopodium, the — centrifugal wood of the stem, when present, consists of only a few — tracheids; in such forms as Lyginodendron, for instance, and in — many ferns, the spiral elements are near the outside, while in 4 Tmesipteris and Phylloglossum, they are in the very center. The variability of the position of the protoxylem in the primary wood bundle, and its consequent unreliability as a phylogenetic character, — cannot be too strongly emphasized. . While the structure of the primary bundles of the vascular cryP togams cannot be used as a guide to their interrelationships, t furnishes an excellent character for the whole group, both living and a fossil forms. ‘The presence in the stem of centripetal primary wood, 4 continuous with the protoxylem, is the distinguishing mark of these — plants. The older French botanists appear to have been perfectly 4 right in characterizing their bois centripete as cryptogamic wood, bie! E the Sphenophyllales, Lycopodiales, and Filicales show this structure a very clearly. The only apparent exception? to the rule is the cala- a mitean series, including the modern Equisetales. A species of Cala- 4 mites, however, the so-called C. pettycurensis, or Protocalamites, has “ recently been shown to have well-developed centripetal wood on the a inner face of the protoxylem canals of the stem (Scott 7). Further, a EaMEs (10), working in this laboratory, has distinguished a mesarch 3 condition, with consequent presence of centripetal xylem, in the etl” 4g of the vegetative and reproductive leaves of several living specie . 3 Equisetum. It thus seems certain that centripetal wood was onC? — well developed in the Calamites and their allies, but in the proces of time has been almost entirely lost. t It is worthy of note that though secondary wood is often pres in the vascular cryptogams, and may constitute the bulk of the cen" cylinder, the protoxylem is intimately associated with the centtip” 2 Exclusive of that aberrant group of ferns, the Ophioglossales. | AY ye ae OR Se ere Pe A RY ee) 1909} SINNOTT—MESARCH STRUCTURE IN LYCOPODIUM 143 etal primary wood. In the higher plants, the centrifugal xylem pre- ponderates, and the protoxylem becomes continuous with it,even in the cases where centripetal elements are present. The only exceptions to this rule occur in foliar bundles. The leaves of living cycads and of the Cordiates show true cryptogamic wood in their vascular strands, with the protoxylem closely associated with it, though in all cases centrif- ugal secondary wood is present. This persistence of a cryptogamic structure in the leaf, among the higher plants, furnishes good evidence of the conservatism of the foliar bundle. Scattered centripetal elements appear in the peduncle of certain cycads and in the coty- ledons of Ginkgo, also seats of vestigial characters, and centripetal wood is fairly well developed in the leaf of Prepinus (JEFFREY 9) and in the stems of many of the Cycadofilices; but in all these cases, the bundle is of the higher type, the protoxylem being continuous with the centrifugal wood. The structure of the vegetative stem, of the floral axis, and of the leaf, in certain living Cycadaceae, shows clearly the transition from the lower type of wood to the higher. In the stem, the protoxylem joins the centrifugal wood and there are no centripetal tracheids. In the stalk of the male cone of Stangeria paradoxa, and to a less extent in the male and female peduncles of three other species of cycads, as shown by Scorr (8), scattering centripetal xylem elements are present. They are not connected with the protoxylem, however, but are sepa- rated by parenchyma from the rest of the bundle, which otherwise is exactly similar to those found in the stem. In the petiole and blade of the cycad leaf, however, there is more than this faint suggestion of ancestral structures; for here, as above described, true cryptogamic Wood occurs, consisting of well-developed centripetal elements directly continuous with the protoxylem. In the petiole, and some- times in the blade, centrifugal wood is present as well. This is sepa- rated by parenchyma from the protoxylem, and appears to be largely, if not entirely, laid down by cambial activity. Its resemblance to a Sigillarian bundle, as noted by RENAULT, is thus pretty exact. Scotr, however, believes that some, at least, of the centrifugal wood 1s primary, and consequently that true mesarch development takes place, a condition which he compares to that found in the stem bundles of Lyginodendron Oldhamium. He presents the mesarch structure 144 BOTANICAL GAZETTE [AucusT 4 of the peduncle and of the leaf as evidence of the affinity of modern — : of mesarch primary wood is limited to no one group of plants, and | that its presence or absence is of no value as phylogenetic evidence. CONCLUSIONS 4 The position of the protoxylem in the primary wood bundle of vascular cryptogams is very variable, for in all of the groups it may be almost anywhere in the strand. It is consequently of little value -in determining the relationship of any group to other groups or to the higher plants. A constant primitive feature in the vas- cular cryptogams, however, is the presence in the stem of cryptogamic : wood—centripetal xylem continuous with the protoxylem elements. — Whenever such a feature occurs in any of the higher plants, it can be used as evidence in tracing their affinity only with vascular cryp togams in general, not with any particular group of them. . I desire to express my thanks to Dr. M. A. CHRYSLER and to Mr. A. J. Eames for assistance in procuring material, and especially 1 Professor E. C. Jerrrey for advice during the course of the work. This investigation was carried on in the Phanerogamic Labo tories of Harvard University. HYANNIs, Mass. . LITERATURE CITED 1. BRoNGnrart, A., Observations sur la structure intérieure du Sigillaria elegans etc. Arch. Mus. Hist. Nat. I: 405-460. 1839. ‘ - MertTentus, G., Beitrige zur Anatomie der Cycadeen. Abhandl. Konigl. Sachs. Gesells. Wiss. '7: 565-609. 1861. a RENAULT, B., Structure comparée de quelques tiges de la flore Carbonifére- . Nouv. Arch. Mus. Hist. Nat. II. 2:213-248. 1879. 4. Sotms-Lausacu, H. Grar zu, Palaeophytologie. Géttingen. 1887. Grson, R. J. Harvey, Contributions towards a knowledge of the anatomy of the genus Selaginella, Part I, the stem. Annals of Botany 8:133? pls. 9-12. 1894. . , Idem, Part III, the leaf. Annals of Botany 11: 123-155- pl. 9- 1601 Scort, D. H., Studies in fossil botany. London, 1908, Part I. x 1S) id ue > oad PANICAL GAZETTE, XLVIII PLATE X RRM Sch faa, aa ts) me 3 . Door ee eee SINNOTT on LYCOPODIUM woe yh tan uae Sal ig SM i la mM ol phot pita acess Te a i . ane . 1909] SINNOTT—MESARCH STRUCTURE IN LYCOPODIUM 145 8. Scorr, D. H., The anatomical characters presented by the peduncle of Cycadaceae. Rieale of Botany 11:399-419. pls. 20, 21. VE 9. Jerrrey, E. G., On the structure of the leaf in Cretaceous pines. Annals of Botany 22:207-220. pls. 13, 14. 1908. 10. Eames, A. J., On leaf structure in Equisetum. Annals of Botany, ined. EXPLANATION OF PLATE X Fic. 1.—Lycopodium inundatum var. Bigelovii; longitudinal radial section through a leaf-trace. 500. 1G. 2.—Lycopodium inundatum var. Bigelovii; transverse section of a leaf- trace near the margin of a mucilage cavity. 500 Fic. 3.—Lyco podium lucidulum; transverse section of a leaf-trace. 500. 1G. 4.—Lycopodium clavatum, longitudinal radial section through the margin of thé central cylinder, showing the single centrifugal metaxylem element on the right. 500. Fic. 5.—Lycopodium clavatum; transverse section through the margin of the central cylinder at the point of departure of a leaf-trace; the dark line of crushed cells marks the position of the protoxylem. 500 Fic. 6.—Lycopodium obscurum; longitudinal ceded section through the margin of the central cylinder, showing centrifugal metaxylem as in fig. 4. X500 Fic. 7. —Lycopodium clavatum; longitudinal radial section ahconiake a leaf- trace. soo. Fic. 8.—Lycopodium clavatum; transverse section of a leaf-trace. 500. Fic. 9.—Lycopodium tristachyum; transverse section of a leaf-trace. X500. BRIEFER ARTICLES SOME HITHERTO UNDESCRIBED PLANTS FROM OREGON ~ Mr. Wir11am C. Cusick has submitted to the writer for determination — an interesting series of castillejas and senecios, collected by him during — the past few years in the Wallowa Mountains of northeastern Oregon. r The material is copious and for the most part falls readily into well-known” species. There are, however, a few plants which do not satisfacto accord with any described species; these may be here characterized follows: Castilleja chrysantha, n. sp.—Herbacea perennis tota planta elandul villosa: caulibus erectis vel ascendentibus 0.5-34™ altis: foliis lineari- E lanceolatis vel lanceolatis vel interdum subovatis 1-3°™ longis 1. 5-10" : latis integris vel trifidis trinerviis crispo-hirsuto-glandulosis, laciniis lineari- . bus acutis patentibus; inflorescentiis spicatis 1.5 to 142™ longis; bractels anguste lanceolatis vel lanceolatis integris vel trifidis flavo-viridibus vel pon rarius paululo purpurascentibus; calyce 13-18™™ longo antice et post oe fisso ad circiter medio altitudinem connato, laciniis oblon: ascentibus; corolla 16-20™™ longa flava; galea recta 4-6™™ longa; 2.5-3™™ longum, labii lobis oblongo-ovatis obtusis calycem superantibuss Bi. capsula oblongo-elliptica circiter 8"™ longa breviter acuminata glabra. In wet meadows at the head of West Eagle Creek, Wallowa Moule Oregon, altitude 2135™, 15 August, 1907, William C. Cusick, no. 320° BA hb. Field Mus. Cat. no. 225021); in moist soil near the source of the me C Wallowa Mountains, altitude 2440™, 14 August, 1906, William no. 3124 (hb. Field Mus.); on dry mountain sides, Kettle Creek, Oregon, tude 1830™, July, 1906, William C. Cusick, no. 31032 (hb. Field Mus.); aa io meadows, Wallowa Mountains, Oregon, altitude 2135™, 19 August, 1997) C. Cusick, no. 3205+ (hb. Field Mus.); source of the Wallowa River, 4" 2440™, 15 August, 1908, William C. Cusick, no. 3324¢ (hb. Field wos subalpine prairie of the Wallowa Mountains, 28 August, 1898, W: William C. no. 2110 (hb. Field Mus.), distributed as “‘Castilleia — Greenman, flowered form.” ‘ The habit and glandular pubescence of this species suggests @ close rela ship to C. viscidula Gray and. C. Covilleana Henderson. From the obits C. chrysantha differs in having a longer calyx with oblong and. rounded oF Botanical Gazette, vol. 48] i as a ea 1909] BRIEFER ARTICLES 147 instead of acute ultimate calyx divisions; the lip is longer in proportion to the galea, and the pubescence is more villous. From C. Covilleana it differs in the less deeply cleft bracts, in the oblong blunt divisions of the calyx, and in the longer exserted lip of the corolla. Castilleja fraterna, n. sp.—Herbacea perennis; caulibus caespitosis numerosis ascendentibus plus minusve flexuosis 0. 5-1 .5°™ altis viridibus vel purpurascentibus in partibus inferioribus glabris, superioribus villosis hinc inde glanduloso-pubescentibus; foliis linearibus vel lanceolatis 1-2. 5°™ longis integris vel trifidis pubescentibus, laciniis linearibus acutis patenti- bus; spicis pauci-multifloris 5°™ vel minus longis; bracteis plerumque trifidis rubris; calyce circiter 2°™ longo exteriore pubescente antice quam postice fissiore laciniis lateralibus 2-lobatis, lobis lanceolato-oblongis obtusis rubris; corollis 2.5-3°™ longis exteriore plus minusve pilosis flavis et rubellis; galea erecta circiter triplo brevior quam tubus flava vel flavo- viridia, margine rubello, labio 2.5-3.5™™ longo basi triplicato plerumque atro-viridi, labii lobis anguste-ovatis acutis vel obtusis ad apicem rubi- cundis; capsula oblonga 8-10™™ longa brevi-acuminata acuta glabra. In alpine regions of the Wallowa Mountains, Oregon, 14 August, 1906, William C. Cusick, no. 3125 (type, hb. Field Mus. Cat. no. 225016); and in the same locality, 27 August, 1907, William C. Cusick, no. 3222° (hb. Field Mus.). Mr. Cusick states that the plants here cited were associated with Salix, and that they grew especially in thickets of S. sitchensis. The numerous subflexous stems, ascending from a common base, each terminated by a conspicuous inflores- cence variegated with green, red, and yellow, render it an extremely attractive species. Castilleja oresbia, n. sp.—Herbacea perennis basi lignosa; caulibus _ Simplicibus erectis vel ascendentibus 1. 524m altis crispo-hirsutis; foliis lineari-lanceolatis et integris vel trifidis 1-4°™ longis 2-5™™ latis eee pubescentibus, laciniis linearibus acutis patentibus; inflorescentus termi- nalibus dense spicatis r.5—4.5°™ longis; bracteis saepissime trifidis, lobis lateralibus linearjhue chine? 30 BAR es Belge ] ato-ovato; calyce 10-14 ™™ longo exteriore pubescente antice et postice aequaliter fisso, lobis oblongis bidentatis; corolla flava 14-17™™ longa glabra, galea recta circiter 6™™ longa, labii lobis lineari-elongatis 4™™ longis acutls; capsula oblonga acuta circiter 1°™ longa glabra. On dry mountain sides, Kettle Creek, Oregon, altitude 1830", 19 August, 1907, William C. Cusick, no. 3201* (hb. Field Mus. Cat. no. 225022). _ In habit and general appearance this species resembles most closely C. rustica Piper, from which it differs in having shorter, more densely flowered, and less Villous spikes, and in the characters of the corolla. A marked distinguishing 148 BOTANICAL GAZETTE [avcust feature of C. oresbia is the straight corolla with the conspicuously long lobes of the q lower lip. ; SeNEcIO HoweLur Greene, var. lithophilus, n. var.—A forma typica recedit foliis multo amplioribus, maximis 3-15°™ longis 1-3.5°™ latis integris vel inaequaliter et alte dentatis. In stony dry soil, Imnaha, Wallowa Mountains, ‘Orem, about 1830”, 12 August, 1906, William C. Cusick, no. 3129 (hb. Field Mus.). Mr. Cusick’s specimens under the number here cited seem at first glance to be more than of varietal significance, but a comparison with the type of S. Howellii and a considerable suite of specimens from the Gray Herbarium and in the 4 herbarium of the Field Museum show the plant in hand to be only an extreme variation with large, broad, entire or coarsely and unequally dentate leaves— a . M. Greenman, Field Museum oj Natural History, Chicago. Be. CURRENT LITERATURE BOOK REVIEWS Ecology of plants For a dozen years English and American botanists have been more or less hopefully awaiting a translation of WARMING’s Plantesamjund, which was — promptly translated into German and thus made available to a larger audience. A peculiar accumulation of misfortunes of one kind or another prevented an English edition of this epoch-making work, but at last WaRMING’s contributions are made available to all English and American botanists, and in the most happy way possible, through the preparation of an essentially new book.t The author has excellent command of the English language, having frequently contributed articles in this tongue. The new volume was written in English by the author himself, assisted by Dr. Martin VanL, and was prepared for publication by Drs. Percy Groom and I. B. Batrour. A preface written by the author calls attention to the more fundamental changes in the English work; these are so many and so important that an extended review is necessary. The introduction contains considerable new matter concerning growth forms (Lebensjormen or Vegetationsformen), together with a new and rather satisfactory Classification of them. ‘There are six categories of growth forms: heterotrophic, aquatic, muscoid, lichenoid, lianoid, and all other autonomous land forms. The final Category is, of course, much the largest, and is subdivided into monocarpic and polycarpic forms. Monocarpic growth forms may be aestival annuals, hibernal annuals, or biennials to perennials. The polycarpic forms are much more numerous, and their subdivision is based largely on the idea of the char- acter of their protection during the severest seasons, taking account of such things as the duration of the vegetative shoot, the length and direction of the internodes, the position of the renewal buds, the bud structure, size, leaf duration, and the adaptation of the nutritive shoot to transpiration. The sub-classes of Polycarpic forms are renascent plants (subdivided into plants with multicipital Thizomes, mat geophytes, and traveling or rhizome geophytes), rosette pease (subdivided into ordinary rosettes and tree rosettes), creeping plants, and panes _ With erect long-lived shoots (subdivided into cushion plants, undershrubs, soft- stemmed plants, succulent-stemmed plants, and woody plants with long-lived lignified stems). tiene 5 eee 149 150 BOTANICAL GAZETTE [AUGUST — The first and second sections, dealing with ecological factors and their action — and the communal life of organisms, are but little changed, except that they are brought up to date, as is true of every part of the book to a most remarkable — egree. Sun and shade plants are called heliophytes and sciophytes respectively, — and their leaves are denominated heliophylls and sciophylls. The third section — s more vital, however, involving new conceptions rather than rearrangement of 3 material, is the new classification of plant formations. Here the author departs — phytes, xerophytes, and halophytes. The new conception is that there is 2 fundamental twofold subdivision into land plants and water plants. The land — plants are subdivided further into twelve primary groups, thus making with the hydrophytes thirteen main classes of plant formations, in place of the four classes of previous editions. For the new classification, the author states that Dr. VAHL is largely responsible, and especially for those following the psammophytes, 4S noted below. In former editions it will be recalled that WARMING objected, and with good bs reason, to the word formation as an ecological unit, largely because of its varied 4 use by different authors. But language is a peculiar thing, and ill-chosen words 4 often stick. It has been so with formation, and the author now attempts 1 3 delimit the word, regarding a formation as “a community of species, all belonging to definite growth forms, which have become associated together by definite a external characters of the habitat to which they are adapted.” ‘The chief of formations are microphyte, moss, herb, undershrub, shrub, and forest, and individual formations may be simple, compound, or mixed. An association 8 defined as ‘‘a community of definite floristic composition within a formation, ‘7 floristic species of a formation which is an oecological genus.” The conception of a formation as an ecological genus and an association as an ecological species E is now becoming generally accepted in principle, but this concrete statement by ee. the father of modern ecology should make its acceptance universal. . The new classification of formations, with some of the leading sub-classes under each, follows. A. Soil wet; water available. (1) Hydrophytes; subdivided into plankton (further split up into haloplankton, limnoplankton, and saproplankton), coe plankton (including the microphytes of ice and snow), hydrocharid forma or pleuston, the lithophilous benthos (in place-of the nereids), the benthos loose soil (including hot spring microphytes, sand algae, saprophytic an phytes, and the enhalid and limnaea formations, as in previous editions). ( Helophytes or swamp plants; subdivided into reed swamps and bush ee” B. Soil physiologically dry. (3) Oxylophytes or plants of sour (i. € soil, characterized largely by xeromorphy; subdivided into low moor, a heaths, high moors, moss and lichen heaths (or tundra), dwarf shrub bes!) and bushland or forest on acid soil. (4) Psychrophytes or plants of cold $0" 1909] CURRENT LITERATURE 151 including chiefly the subglacial fell-fields. (5) Halophytes; subdivided into lithophilous, psammophilous, and pelophilous halophytes, salt swamps an deserts, and littoral swamp forests (mangrove swamps). . Soil physically dry and dominant in determining the vegetation. (6) Lithophytes; subdivided into the true lithophytes (chiefly lichens) chasmophytes, and shingle and rubble plants. (7) Psammophytes or sand plants. (8) Cherso- phytes or waste plants (i.e., ruderals); subdivided into waste herbage and bushland on dry soil. D. Climate dry and dominant in determining the vegetation. (9) Eremo- phytes, or plants of steppes and deserts; subdivided into deserts, shrub steppes, and grass steppes (including prairies). (10) Psilophytes or savanna plants; subdivided into thorny savanna, true savanna, and savanna forest. (11) Sclero- phyllous plants; subdivided into garique, maqui, and sclerophyllous forest. E. Soil physically or physiologically dry. (12) Conifers. F. Soil and climate favorable to mesophilous formations. . (13) Mesophytes; subdivided into arctic and alpine mat grassland, meadow, pasture, mesop: ytic bushland, deciduous dicotylous forests, and evergreen dicotylous forests. The classification here outlined does not strike the reviewer as an improve- ment over the one abandoned. For the most part the new groups of land forma- tions are segregates from the old term xerophyte. It is true that the latter term had become unwieldy, but it is questionable whether the difficulties are solved. Among the advantages of the new scheme is the recognition of close relation- ship between heath and moor plants, which together form the category oxylo- phytes, and also the close ecological relationship between these plants and the plants of cold and salty soils, as emphasized by SCHIMPER. It is gainful, too, to put the edaphic xerophytes (lithophytes, psammophytes, chersophytes) into one category and climatic xerophytes (eremophytes, psilophytes, sclerophylls) into another. Among the disadvantages of the new arrangement are many instances Where unrelated things are placed together and related things are separated. The most conspicuous case of the former is seen in class 12, the conifers. While this _ Sroup is a floristic unit, and even an ecological unit from the anatomical stand- point, it is far from being a geographic unit of any sort. It would seem better to put many conifers with the lithophytes and psammophytes, while others are as between lithophytes and psammophytes, oxylophytes and pen - northern regions, etc. It also seems unfortunate ular, and it seems a pity to have to brush the dust once more from our Greek ‘ lexicons. The antiquated spelling of ecology (oecology) is unfortunate, and is 152 BOTANICAL GAZETTE [avcusr made more striking by contrast with the frequently used economy, which has _ the same reason for appearing as oeconomy. : While words of adverse criticism seem necessary here and there, one may write volumes of praise. WARMING’s Plantesamfund will be for all time the : great ecological classic, and the English volume now before us is the most impor- tant ecological work in any language. It is at the same time an old book and a new, a translation of the masterpiece of 1895 and a compendium of the eco- logical thought of 1909. ARMING has been contributing to ecology for more than forty years, and is the undisputed Nestor of the subject, but unlike many 4 Nestor, WARMING incarnates the ambitions and plasticity of youth. It will be pleasing to American ecologists to see the remarkable recognition accorded to their work in this new volume. The German edition of 1896 contained but one American title, though a half-dozen more might have been included. Now there are 600 titles in all, almost exactly twice the number published in 1896, a and it is not unfair to say that half of the ecological work thus far accomplished 4 is represented by the added titles of the last thirteen years. It will be flattering _ to Americans to note that 115 of the 300 new titles represent American contribu- tions, a record that measures up well with the bare half-dozen that might have been named in the original 300. The new edition has ample footnote references, adding inestimably to the service of the work. The absence of illustrations will be a source of disappointment to many, but it accounts in large part for the extremely low price of the volume, a price that will insure a sale that has been ac corded to no ecological work in the English language—HENry C. CowLes. Experimental morphology : Although experimental morphology received its, original impetus from oa a vations on plants, during the last few years there has been a great dearth # form. PFEFFER’S Especially interesting is the first chapter, which considers the nisi 3 experimental morphology, for here the author reveals his philosophy. It's « ihe that GOEBEL goes about as far as Kiers in referring plant phenomena 0 influence of external factors, and he follows Kress in holding that the ordinary ? Gorsel, K., Einleitung in die experimentelle Morphologie der Pflanzen. = pp. vit 260. jigs. 135. Leipzig and Berlin: B. G. Teubner. 1908. 1gog| CURRENT LITERATURE 153 succession of events in the life-history of a plant is no more normal than any other succession of events that may be produced by altering the external condi- tions. Like Kiess, therefore, he is obliged to discard the word normal or place it in quotation marks. To the reviewer such a viewpoint seems fundamentally sound, and it has the added attraction of throwing open to experimentation all the phenomena of development, including those that have been referred to hered- ity or mysterious internal causes. In harmony with this fundamental principle, illustrations are given of the omission of individual stages from a developmental series, the transposition of two such stages, and the retention of a given stage, if the conditions favorable to another are not forthcoming; even the juvenile stages may be retained through life in many instances, if the external conditions are favorable thereto. On the other hand, there are cases where juvenile forms bear flowers, the intervening stages being skipped. The body of the book consists of four chapters, dealing respectively with the influence of external and internal conditions on leaf form, the conditions deter- mining variations in the development of main and lateral axes, regeneration, and polarity. In all of these chapters there is a wealth of detail of the utmost value to students in experimental morphology and to those desiring a bibliography of these subjects. Not only is the literature summarized, but there are many new and suggestive experiments mentioned here for the first time. In the chapter on leaf form, heterophylly in xerophytic species of Veronica and in such amphib- tous plants as Limnophila plays an important part. Mutation in some ferns is definitely referred to the operation of external factors. Plants with orthotropous and plagiotropous shoots are found to belong to two categories. For example, lateral branches of the spruce (Picea excelsa) become orthotropous if the termi- nal shoot is removed, while such a reaction does not occur in Araucaria; the former illustrates lability, the latter stability. The same chapter contains some very interesting data concerning variation in flowers and inflorescences. Of SR aps it seems not to get down to fundamental principles. Throughout the the work nutrition is regarded as a dominant external factor. Whileitis true that it is as yet impossible to resolve nutrition into its components, it is at least better pa to do so than to assume that ition is reall thing definite, or even a te. To many of us the work will be more useful as a summary of facts as an explanation of the conditions underlying them.—HENry C. COWLES. ally tt > 154 BOTANICAL GAZETTE [aucust The vegetation of Switzerland Curist’s Das Pflanzenleben der Schweiz was published in 1879. A French translation of this work entitled La flore de la Suisse et ses origines appeared in 1907.3 An apology is due the author and publishers for the tardiness of this review. The translator is E. Trécur, and the author has added a supplement in which he summarizes the geobotanical work that has been done since the publication of the first edition. As the original work has never been reviewed in the GAZETTE, a summary of its contents may be acceptable. After a brief discussion of the fundamental principles of plant distribution, especially the influence of climate, and migrations, the vegetational regions of Switzerland are described in great detail. The primary divisions are naturally zonal in form, since the country is so largely mountainous. The author enumer- rates four zones: (1) the basal zone, having considerable likeness in its flora to the Mediterranean region, and largely under cultivation, with the grape as the characteristic culture plant; (2) the zone of deciduous forest, dominated in the south by the chestnut, in the north by the beech; (3) the zone of coniferous forest, composed of spruce, fir, larch, and Cembran pine; (4) the alpine region, to which a third of the discussion is devoted. Here particularly the author om siders the problems of migration, tracing an important element among the alpine plants to the mountains of north-central Asia as their point of origin. The large endemic element of the alpine flora is also discussed at some length. The work is characterized by minuteness of detail, possible because of the thoroughness with which the Alps have been explored and studied by botanists. Such a work is hardly yet possible in any portion of our country. The supplement, which is a résumé of the work of recent students, adds nothing of general importance, but merely fills out details here and there. It would seem that in view of the great advance that has been made in the study of plant geography during the thirty years since the appearance of the first edi- tion, a better plan would have been to rewrite the whole.—WuiLL1AM S. CooPER- MINOR NOTICES Local tree floras—RAMALEY has published a thin volume+ whose really useful part consists of descriptions of the trees of Colorado, with analytic keys and a considerable number of illustrations. These will be helpful to those W pages on the “wild flowers” of the State, with many halftones of vegetation pes scenery, and a number of good outline drawings. The title, Wild flowers We trees of Colorado, is thus literally justified, but practically it is misleading- hoped from the announcement to see a popular flora embracing the commone! 3 Curist, H., La flore de la Suisse et ses origines. pp. xiv+ 571 +119: yee maps 5. Bale-Geneva-Lyons: Georg & Cie. 1907. e 4 RAMALEY, F., Wild flowers and trees of Colorado. 8vo. PP- vit 78. Aes " Boulder, Colo.: A. A. Greenman. 1909. : 1909] CURRENT LITERATURE es plants of the state, after the fashion of some of the excellent books on the eastern flora. The demand for this sort of a book, we hope, will induce Dr. RAMALEY to prepare such a volume. The tourist travel alone would doubtless quickly absorb a reasonable edition. MACKENSEN, a teacher in the San Antonio (Texas) High School, has pub- lished, as well as written, a handy a little pamphlets on “‘all the woody plants growing naturally within five or six miles of the center of the city of San Antonio.” According to the author’s investigations there are just one hundred such species, of which at least ten are introduced. This number of species is surprisingly large, but is due to the author’s lax conception of woody plants, for we find included various vines, agave, and the cactuses, not to mention a herbaceous mallow described as ‘‘woody below.” The descriptions are untechnical, and there are some interesting observations on certain species. The lack of a key will limit the usefulness of the pamphlet.—C. R. B. Asiatic palms.—The present volume, a monographic presentation of the species of Calamus,® records the results obtained by a careful specialist after years of study of living plants in their native habitat and the critical examination and comparison of dried specimens from the larger herbaria of the world. The subject-matter is arranged under ten headings, the first being an introductory essay of forty-five pages giving a detailed discussion of all parts of the plants entering in any way into their classification, the treatment of the genus by former authors, present limitations, especially with reference to Daemonorops and Palmijuncus, and finally the geographical distribution of species. The author then introduces the taxonomy by giving a systematic conspectus of the species, arranged in sixteen groups, based primarily on the presence or absence of leaf-cirri, and further on the characters of the leaf sheaths and inflores- cence; the conspectus is followed by a synopsis of the species (brief characteri- zations of the 201 recognized species); and lastly their enumeration with bibliog- raphy, detailed descriptions, and copious notes. With the exception of five species, known only from Rumpn’s descriptions and figures, all of those treated in the text have been beautifully illustrated by natural-size phototype repro” ductions from the author’s own negatives. A complete index to species and plates concludes the volume. The work is an important contribution to taxo- nomic literature —J. M. GREENMAN. A forcing process.—JOHANNSEN’s process of forcing plants by treatment with ether vapor has been of considerable service in the commercial production of unseasonable flowers. A much simpler and in every way more practicable S MACKENSEN, B., The trees and shrubs of San Antonio and vicinity: a book of the woody plants growing naturally in and about San Antonio, Texas. 12m0. Paper. pp. 51. pls. 12, San Antonio: The author. 1909. : 6 BEccarr, Opoarvo, Asiatic palms—Lepidocaryeae. Part I. The species of Calamus, Ann. Roy. Bot. Gard. Calcutta 11:1-518. pls. 238. 1908. 156 BOTANICAL GAZETTE [AUGUST E process is described by Mo iscu in a little pamphlet, entitled Das Warmbad.? — The treatment consists merely in immersing the shoots of potted plants (by inver- _ sion) in water of 30-35° C. for 9-12 hours and then keeping them in a warm — (25°), moist, dark chamber until the leaves begin to appear, when further develop- c. ment proceeds under ordinary greenhouse conditions. Lilacs and spiraeas treated _ to the warm bath about mid-November flowered before Christmas, and azaleas 3 early in January; while untreated plants, under the same conditions, had at : this time hardly started their buds. The exact duration and temperature of the a bath for securing the best results vary with different species and races. The = process is.already in use and is likely to be extensively practiced—C. R. B. 4 The flora of Korea.—The first part of this work® includes the families Ranun- q culaceae to Dipsaceae, and their sequence is essentially that of BENTHAM and — ning of each genus precede the enumeration of species. Under the species a very full bibliography is given, as well as the citation of exsiccatae and the general distribution. The Japanese name is also given in many cases. Several new species and varieties are published, and the text is augmented by fifteen full- page clean-cut illustrations. An index to genera mentioned in the flora com cludes the part.—J. M. Greenman. North American Flora.—Volume XV II, Part I, of this work? contains the ollowing groups: Typhaceae by P. Witson; Sparganiaceae, Elodeaceae, and Hydrocharitaceae by P. A. RypBERG; Zannichelliaceae, Zosteraceae, Cymodo- raceae, Naiadaceae, and Lilaeaceae by N. Taytor; Scheuchzeriaceae by N. L. Britton; Alismaceae by J. K. SMALt; Butomaceae, Poaceae (pars) by G. V. ASH. New species are described in the following genera: Sparganium (2), Echinodorus (1), and Trachypogon (2). One new genus (Machaerocarpus) ¢ the Alismaceae is proposed, being based on Damasonium californicum Tort— J. M. GREENMAN. Diseases of trees.—A bulletin, embodying the results of a number of years investigation of some of the more important diseases of deciduous trees by VON SCHRENK and SpavLpiNe, has been issued by the national Bureau of Plant Industry.*° The bulletin contains a large amount of information (there is unfor- tunately little available) on diseases due to environment, to wound fungi (far 7 Motiscu, H., Das Warmbad als Mittel zum Treiben der Pflanzen. 8Y pp. 38. jigs. 12. Jena: Gustav Fischer. 1909. M 1.20. 8 Nakal, T., Flora Koreana. Pars Prima. Jour, Sci. Coll. 26:1-304. Pls- ii} TQO9, : ° North American Flora, Vol. XVII, Part I, pp. 1-98. New York Botanical Garden, 1909 : 5 H. von, AND SPAULDING, P., Diseases of deciduous forest trees ? CHRENK, Bur. Pl. Ind. U. S. Dept. Agric. Bull. 149. pp. 85. pls. 10. figs. II. 1909- E 1909] CURRENT LITERATURE 157 the largest category), and to miscellaneous parasites and saprophytes, with some discussion of the decay of structural timbers. The Polyporaceae are the greatest devastators of our forests. A useful bibliography is appended.—C. R. B. Vegetationsbilder.—The third part of the seventh series of KaRsTEN and SCHENCK’s well-known work?! presents six plates of the vegetation of the moors, Bockser (high plains with dry grasses and sedges), and forest of the northern Schwarzwald, with text, by Orto Feucut; the fourth illustrates the sea strand, littoral, sublittoral, and submontane formations on the Dalmatian coast, with xt by L. Apamovic; while the fifth pictures the various curious plants charac- teristic of the Abyssinian highlands.—C. R. B. NOTES FOR STUDENTS Taxonomic notes.—O. Brccart (Phil. Jour. Sci. 3:339-342- 1908) has de- scribed 3 new species and 2 new varieties of ferns from the Philippine Islands.— R. C. Benepicr (Bull. Torr. Bot. Club 36:41-49. 1909) records 4 new hybrids in the genus Dryopteris from eastern America.—C. CHRISTENSEN (Rep. Nov. Sp.- 6: 380, 381. 1909) records a new species of Dryopteris from Brazil.—A. COGNIAUX (tbid. 304-307) publishes 5 new species of orchids from Jamaica.—F. S. CoLLINs (Rhodora 11:17-20. pl. 78. 1909) has published 4 new species of the genus Cladophora, and (ibid. 23-26) under ‘‘Notes on Monostroma” records a new form of Monostroma orbiculatum from Massachusetts —E. B. CopELAND (Phil. Jour. Sci. 3: 343-357. pls. 1-8. 1908), under the titles “New genera and species of Bornean ferns,” and “New species of Cyathea,” has published 20 new species and 2 new genera (Macroglossum and Phanerosorus).—L. A. DoDE (Bull. Soc. Bot. Fr. IV. 8:648-656. 1908) describes 12 new species and 3 new hybrids of trees and shrubs; these include a Robinia from Colorado and a Salix from New Jersey —F. E1cutam (Monats. Kakteenk. 19:1-5. 1909) characterizes a new species and 4 varieties of Mamillaria from Guatemala, and (ibid. 22-25) describes a new species of Pereskiopsis from the same general region.—A. D. E. ELMER Leafl. Phil. Bot. 2:445-594. 1908-1909) has described ror new species and 3 Varieties of Philippine plants. A new genus (Elmeria Ridl.) of the Zingiberaceae 's proposed, and a synopsis of the genus Rubus is given, in which the author Fecognizes 17 species for the Philippine Islands, 3 being new to science~+*. ENGLER (Bot. Jahrb. 43:161-198. 1909) has published new species of African plants as follows: ro in the Olacaceae, rz in the Opiliaceae, 2 in the Octoknema- taceae, 11 in the Icacinaceae, and 13 in the Aizoaceae——E. GILG (ibid. 97-128), in an article entitled ‘‘Balsaminaceae africanae,” recognizes 85 species of Impa- tiens from Africa, and of these 26 are new to science.—M. Gtxe (ibid. 199, 200) records 3 new species of Ebenaceae from Africa, and (Monats. Kakteenk. 19: 12-14. 1909) describes Rhipsalis Novaesii and accompanies the description by illustrations of the flower; the plant is a native of Brazil—W. Herter (Bot. ————— Karsten, G., aND SCHENCK, H., Vegetationsbilder. Series vii, parts 3-5- text and pls. 13-30. 4to. Jena: Gustav Fischer. 1909. M 4 per part. 158 BOTANICAL GAZETTE [AUGUST Se en es Jahrb. 43: Beibl. No. 98, pp. 1-56), under the title “Beitrage zur Kenntniss der Gattung Lycopodium,” has published 48 new species, of which 30 are from the West Indies, Mexico, Central and South America—J. D. Hooker (Kew Bull. — I-I2. 1909) presents the results of recent studies in the genus Impatiens from — Indo-China and the Malayan Peninsula, recognizing for this region 27 species, — of which 5 are new to science; a key precedes the enumeration of species.— M. A. Howe (Bull. Torr. Bot. Club 36:75-104. 1909) has published 7 new species of the Siphonales, and presents also a synoptical key to the living species of Neomeris.—F. KrANzLEIN (Rep. Nov. Sp. 6:317. 1909) records a new species of Dendrobium from the Philippine Islands —K. KRAUSE (Bot. Jahrb. 43:129- 160. 1909) has published 4o new species of Rubiaceae from Africa—E. D. — Merritt (Phil. Journ. Sci. 3:359-358. 1908) gives a synopsis of the Philippine — species of Garcinia, recognizing 17 species, of which 5 are new; the same author (bid. 369-382), under the title “Philippine Ericaceae,” presents a consideration of the four genera representing this family in the Philippines, and accompanies -Vaccinium (19 species) and Rhododendron (16 species) with determinative keys, — characterizing 3 species and one variety as new; further, he gives (ibid. 385-442) a list of plants from the Batanes and Babuyanes Islands, describing 16 new species—E. Pax (Bot. Jahrb. 43:218-224. 1909), under the title “Euphor- biaceae africanae X,” has published I5 species new to science, and proposes 2 new genera (Holstia and Neopycnocoma); the same author (ibid. 75-99) describes 43 species and 4 varieties of Euphorbiaceae as new to science.— J. PerKins (ibid. 214-217) publishes jointly with E. Gitc a new genus (Ajro- styrax) of the Styracaceae; the genus is represented by one species, A. hame- runensis, from Kamerun.—R. Pricer (ibid. 91-96), under the heading “Gramineae africanae VIII,” describes 8 new species of grasses.—J. A. PuRPUS (Monats. kteenk. 19:38-4r. 1909) describes and illustrates a new species of Cereus from Mexico.—B. L. Roprinson and M. L. FERNALD (Rhodora 11: 33-61. 1909); under the title ‘‘Emendations of the seventh edition of Gray’s Manual I,” has a given an annotated list of corrections, additions, extension of ranges, etc-; — A includes a new species of Callirhoé from Missouri.—R. A. Rotre (Kew Pu™ 61-66. 1909), in an article entitled ““New Orchids: Decade 33,” publishes 19 new species, of which 4 are American.—E, RosENSTOCK (Rep. Nov. Sp. 630% 316. 1909) has published 9 species and 4 varieties of ferns as new to science; these are based on collections made by Dr. O. Bucntten in Bolivia.—D i authors (ibid. 341-352), under the title “Ex herbario Hassleriano: Novitates trea Lge a, a ir ee Bi li. EB a ak Ee it a Bical: ve on = 3 is bee aes ANG : “ie Le Botaniste 10:177, etc. 1909] CURRENT LITERATURE 159 and P. C. Sranpiey (Bull. Torr. Bot. Club 36: 105-112. 1909) have described Ir species and one variety of flowering plants as new to science; these are based ‘chiefly on the collections made in Mexico by O. B. Metcatr.—J. M. GREENMAN. Morphology of Monascus.—BaRKER'? and OLive’3 in their investigations of Monascus describe the ascogenous hyphae as arising from an oogonium, which has been fertilized by an antheridium, thus establishing a true sexual process for this form, while Kuyrer’4 denies any fusion of sexual cells. IKENO*S asserts that there are no ascogenous hyphae in Monascus, but that uninucleate cytoplasmic masses arise by free cell formation from the ascogonium, which in turn divide also by free cell formation to form the spores. Kuyper in the main agrees with IkENO as to the absence of sexual cells at the origin of the perithecium, while BarKER and OLIvE hold that the asci arise from the cells of the ascogenous ds DANGEARD the ascogonium divides into several cells, each of which gives rise to binucleate cells, which form the asci and whose nuclei fuse. ScHIKORRA?? has recently investigated pure cultures of two species of Monas- cus, M. purpureus Went. and an undetermined species, and believes that he has explained the inconsistencies of the above-mentioned authors. The life-history of both these species is similar. The female organ arises as a multinucleate subterminal cell of a hypha. This cell later divides into a trichogyne and Oogonium. The apical cell is a multinucleate antheridium and fuses with the trichogyne, into which the male nuclei pass by means of a pore. There is an evident gap in observations at this point and the author next describes the male and female nuclei as arranged in pairs in the ascogonium. From the hypha below the sexual organs investing hyphae arise, which form a two-layered peri- thecial wall. Ascogenous hyphae originate from the fertilized oogonium. These hyphae contain nuclei in pairs, which multiply by conjugate divisions, although no such divisions are figured. The asci are formed from the subterminal cells ease ee ‘? Barker, P. T. B., The morphology and development of the ascocarp of Monascus. Annals of Botany 1'7:167—236. 190 _ 13 Oxive, E. W., The morphology of Monascus purpureus. BOT. GAZETTE 39: 50-60. 1905. : ; 4 Kuyper, H. P., Die Peritheciumentwicklung von Monascus pur pureus Went. und pi Barkeri Dang., so wie die systematische Stellung dieser Pilze. Ann, Mycol. I TKENO, S., Ueber die Sporenbildung und penser: Stellung von Monascus pur peas West Ber. Deutsch. Bot. Gesells. 21:259-269- 1993- GEARD, P. A., Recherches sur belies he du périthéce chez les Asco- 1907 '* SCHIKoRRA, W., Ueber die uewickivanasechices yon Monssces. Zeits. Bot. 12379-410. 1909. v3 Bate s er 160 BOTANICAL GAZETTE [Aucusr x of the recurved tips of these ascogenous hyphae. The ascus contains two nuclei, which fuse, and this fusion nucleus divides by a triple division to form the eight — nuclei of the ascospores. The two ascus nuclei are looked upon as male and female, — and their fusion completes the union of the gametes which initiated the develop- 4 ment of the perithecium. The method of spore formation was not made out. a The ascus walls finally degenerate, leaving the spores free in the perithecium. _ From his studies Scurkorra concludes that Monascus is a true ascomycete, — belonging to the family Aspergillaceae, in the order Plectascineae. It is placed 4 here on account of the similarity of its perithecium to that of Penicillium and ¥ Aspergillus. ¢ The presence of a true sexual process in the Ascomycetes has been estab- lished beyond a doubt in a considerable number of forms. ‘The investigations 4g of several species have shown, however, that a normal sexual process is not o5 be expected in all. The apparent absence of any nuclear fusion in the fertili ' oogonium, although the sexual nuclei become arranged in pairs, brings Monascus ~ into harmony with CLAussEN’s results on Pyronema, in which nuclear fusion is claimed to occur only in the ascus, a sort of modified sexual process, therefore, being present. Realizing how difficult it is observe nuclear fusion in the oogonium, S contention that there is a tendency in the Ascomycetes to form a 5% karyophyte analogous to that of the Basidiomycetes.—J. B. OVERTON. gases in these plants; but it is impossible to interpret KoLToNnskKI’s results. ‘ presents them, indeed, as only a starting-point for further investigations- C.R.B. § Kortonsxt, A., Ueber den Einfluss der elektrischen Stréme auf die Ko sdureassimilation der Wasserpflanzen. Beih. Bot. Centralbl. 23: 204-271. SS: 1909 9 THOUVENIN, M., De l’influence des courants électriques continus sur la —_ position de l'acide carbonique chez les végétaux aquatiques. Rev. Gén. Bot. 8:435° 806. ee 450. I i. XLVI . OTANICAL GAZETTE September 1909 Editors: JOHN M. COULTER and CHARLES R. BARNES CONTENTS ta nts! Preliminary Account of the Ovule, Ketmetepexteest and Embryo of Widdringtonia cupressoides T. Saxton ee ee ee GER ed AT WPT Seca Py The Behavior of Chromosomes in Oenothera lata x 0. gigas Reginald Ruggles Gates The Development of the Embryo Sac of Smilacina llata Be neni ie 12. X3I10. Fic. 14.—Body cell nucleus of fig. 13. 1240. 1G. 15.—Upper half of median longitudinal section of nucellus, 1”, and prothallus, p, showing position of pollen tube and of archegonia; drawn from sev- eral . t, pollen tube; January 7, 1909. X28. Fic. 16.—The lowest group of archegonia of jig. 15, two containing pro sunbigee Xt G. 17.—Suspensor bearing a single embryo cell at its apex; note multi- nucleate prothallus cells in this and previous figure; s, suspensor; ¢, embryo cell; January 7, 1909. X310. 1G, 18.—Very young embryo in median longitudinal section; March 8, 1968 Fic. 19.—Older embryo, showing dermatogen differentiated and embryonal tubes; January 7, 1 Fic. 20.—Outline sketch of median longitudinal section of nearly mature embryo; March 8, 1908. Xg. Fic. 21.—Two multinucleate cells from an old prothallus; March 8, 1908: X54. Fic, 22.—Dividing nucleus from an embryo between the ages of those shown in figs. 17 and 18 respectively. X 1500. BOTANICAL GAZETTE, XLVIII a Ge Booey SEN ee, ee Rees ee. z A 4 i) ists # ah, oS EER PLATE XI THE BEHAVIOR OF THE CHROMOSOMES IN OENOTHERA LATAXO. GIGAS OCNTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 128 REGINALD RUGGLES GATES_ (WITH PLATES XII—XIV) The hybrid which forms the subject of this paper is of peculiar interest because one of its parents has double the number of chromo- somes possessed by the other, O. Jata having usually 14 chromosomes and O. gigas 28. Very few cases of this sort are known, either in plants or animals. But a further complication arises in the fact that O. gigas is known to have originated from O. Lamarckiana, which also has 14 chromosomes, and O. gigas has in all probability attained the tetraploid number by a duplication of the chromosome set present in O. Lamarckiana.:_ Then if fertilization took place in the ordinary manner, the hybrid O. lataX O. gigas would be expected to have 21 chromosomes, 7 derived from the lata egg and 14 (which is probably a double set of Lamarckiana chromosomes) derived from the male cell of gigas. Under these circumstances, the behavior of the chromosomes in the hybrid, especially during the period of reduc- tion and germ-cell formation, is a matter of especial interest. The general results regarding chromosome numbers and distri- bution were obtained some time ago, and a brief statement was pub- lished (10), but the cytological evidence is here presented for the larger ones, there has been a transverse split of the D. rotundifolia ch 179] [Botanical 180 BOTANICAL GAZETTE [SEPTEMBER first time. Many of the drawings for these figures were completed about two years ago, but my interest in other phases of this work has postponed their publication until now. The earlier stages of reduc- tion in Oenothera, up to the end of the heterotypic mitosis, have already been described in detail (11), so that this paper will deal chiefly with the later stages, beginning with the metaphase of the heterotypic mitosis. The plants from which these studies were made were grown at Wood’s Hole, Mass., in 1g05 and 1906, from seeds of DEVRIES. The results show that in some cases the number of chromosomes is. undoubtedly 21, while in one individual it was 20.2. The number is undoubtedly constant in an individual, however, as shown by @ — large number of counts, which demonstrated constantly 20 in one case and 21 in the other. q The external characters were not studied with sufficient care at that time to describe them accurately, but from my notes they appeal to have been intermediate between O. lata and O. gigas. DEVRIES has described in a recent paper (5) the hybrids of O. gigas with other forms. I have called attention elsewhere to the fact that the behavior of O. gigas in hybridization, as well as its number of chromosomes, places it in a different category from the other mutants of O. Lamarcki- ana. DeVries finds that O. gigasxO. Lamarckiana forms a Com Stant race intermediate between the parents, at least to the second hybrid generation. O. gigasxO. Lamarckiana, O. Lamarckiana XO. gigas, O. gigasXO. brevistylis, O. gigasxO. rubrinervis, and O. rubrinervisXO. gigas, all give constant hybrid races which at externally alike in all these crosses. O. lataXO. gigas; howevel gives in the F, two types, about 50 per cent. of each; type I inter mediate between O. lata and O. gigas, type II intermediate between - Lamarckiana and O. gigas. These presumably would all ae about 21 chromosomes. There were 13 3 plants in the culture : this hybrid in 1907 and a smaller number in 1908. : Miss Lutz (24) from a study of 4o individuals of O. lata XO. 88° finds more complex conditions in this cross, though apparently * * In my first paper (8) this individual was thought to be O. lata XO. Lamarcke* soa shed mks rd —— to be derived from fertilization by foreign signs lene particular seed pac not having bee when were plarited. Be ng been guarded as was supposed Pe Pat eT eee wet ee rane wart ts aed ee 1909] GATES—CHROMOSOMES IN OENOTHERA 181 _has failed clearly to recognize the types included in her class II. _ She divides the offspring into three classes. Class I has the characters of pure O. lata, and the two individuals which appeared are each _ Said to have 15 chromosomes. Class IT consists of O. gigas plants _ having about 30 chromosomes. There were six of these plants, and their presence cannot be accounted for by the ordinary methods of fertilization. If the O. gigas male cell united with two O. /ata nuclei in the embryo sac, this would account for the origin of the O. gigas number of chromosomes. But GEERTS (12, 13) finds that the embryo sac of Oenothera contains only four nuclei, the egg, two _synergids, and one polar nucleus, so that the possibilities here are _ more limited than in an 8-nucleate sac.* The class III of Miss Lutz apparently includes both the types of DEVRrEs’s cross, but they are - hot characterized so that a comparison can be made. These interesting facts all show that there is still much to be _ explained regarding O. gigas and its hybrids. In the paper already _ referred to, I have shown that, in all the tissues examined, the cells _ are larger in O. gigas than in O. Lamarckiana, though the percentage _ of increase varies in different tissues. The production of the tetra- ploid number of chromosomes results in larger nuclei and larger cells, and this in turn in many cases produces larger organs. Certain changes which are found in the relative dimensions of the cells will a account for the altered shape of certain organs. Thus the differences 3 between O. Lamarckiana and O. gigas can probably be analyzed __ into two factors, (r) increased size of the cells, and (2) altered relative a dimensions of the cells in certain cases. The former undoubtedly 2 ‘embryo sacs are produced without reduction (a ously or aposporously), in = which case the egg develops without fertilization. I hope to test this hypothesis _ ©xperimentally this summer a 4 Whether an individual with the tetraploid number of chromosomes would have a the O. gigas characters, owing to its number of chromosomes rather than their 2g 4 18 a question I have considered in a forthcoming paper (footnote 1). bet inietsare 182 BOTANICAL GAZETTE {SEPTEMBER results directly from the doubling of the chromosome number; at least the double number of chromosomes and the larger size of cells occur simultaneously. Whether the latter isa necessary consequence upon the increase in cell size and a resulting change in cell relations, or is due to an independent factor, is uncertain. It should be said that characters, such as leaf shape, which might be accounted for by a change in the relative dimensions of the cells (though I have not as yet made measurements of the leaf cells to determine this), are extremely variable, and it seems not unlikely that this extreme varia- bility may result from variation in cell dimensions consequent UpuD the readjustment to the double chromosome number. : DESCRIPTION The cytological account will begin with the telophase of the heterotypic mitosis in the pollen mother cell. The ten figures in plate XII are from the plant having 20 chromosomes, and were drawn on a smaller scale than those of the other two plates. At this stage the chromosomes can be counted with perfect accuracy. A large number of counts of this telophase show that 10 chromosomes enter each daughter nucleus. In a number of cases 10 were counted at each end of the same spindle. In several instances 11 were found in one — of the daughter groups, and in a few cases it was possible to show that the corresponding daughter group contained only 9 chromosomes. In this plant, then, there are 20 chromosomes which segregate into two groups of ro each in the reduction division, one chromosome occasionally going to the wrong group. Counts of somatic cells, made long ago in tissues of the anther, also showed that 20 chromo- somes were present. _ The material from which the figures in plate XII were drawn was subjected to an exceptionally high temperature in the process of | imbedding, and in a few cases this has apparently affected the shape of the viscous chromosomes. Figs. 1-5 are early telophases before the formation of a nuclear membrane. In fig. 1 the chromosomes nearly all show their bivalent nature, and in most of them the two halves are dumb-bell shaped. This clubbing of the chromosome? at the ends is a common phenomenon both at this time and in the telophase ofthe homotypic and somatic mitoses. I have already 1909] GATES—CHROMOSOMES IN OENOTHERA 183 referred to these appearances in an earlier paper (9,‘p. 19). In jig. 2 the chromosomes are more irregular in shape, and their bivalent character is not so evident. There are 11 chromosomes in the daughter group, and examination of the adjacent sections showed that there were g and no more at the other end of the spindle. The globular black bodies seen in the figure are frequently found scattured near the periphery of the cytoplasm. They stain like chromatin with Haidenhain’s iron alum hematoxylin, but their chemical nature is unknown. Figs. 3-5 each show 10 chromosomes. Fig. 6 is a telophase with 11 chromosomes, the next section showing 9 at the other end of the spindle. Fig. 7 is an exact polar view, the other figures being more or less oblique cuts of the spindle, but the spindle fibers are not represented. Figs. 7, 8 are somewhat later stages in side view, soon after the nuclear membrane is formed. Ten chromosomes are present in each. In figs. 9, ro are shown in outline the loop-shaped chromosomes of two somatic cells. Each has 20 chromosomes. ‘The cells are from the middle layers of the anther wall. Plates XIII and XIV deal with plants having 21 chromosomes. Fig. 11 is a side view of the heterotypic spindle, showing 20 or 21 chromosomes. It is usually difficult to count the chromosomes _ exactly at this time in a side view of the spindle, on account of the close aggregation of some of them, and the presence of spindle fibers. he chromosomes are almost never regularly oriented in an equatorial plate on the heterotypic spindle. An examination of the literature shows that in most plants and animalsa flat equatorial plate is formed in the metaphase of this mitosis as in other mitoses, although a few forms constitute exceptions. But the homotypic mitosis in Oenothera has always a very definite equatorial plate, in which the chromosomes are oriented in a single plane. There can be little doubt that the irregularities in chromosome distribution arise from this failure of the chromosomes to be regularly paired and oriented on the heterotypic spindle. The irregularities in distribution certainly arise at this time. I have recently confirmed practically all the events of reduction by a study of the wild O. biennis, so that this account of reduction applies to the genus Oenothera in general and is not the result of mutative conditions. This will be referred to again later. 184 BOTANICAL GAZETTE [SEPTEMBEK Fig. 12 is another cell in telophase. One nucleus is uncut, show- 3 ing 10 bivalent chromosomes. The other was sectioned by the knife. — Fig. 13 shows 11 chromosomes and a number of very small nucleoli. — Usually only one or two larger nucleoli are present. In fig. 14 there — are 12 bivalent chromosomes. In such cases g appear at the opposite end of the spindle. Figs. 17, 18 are very early telophases just after the nuclear membrane has been formed. The daughter nuclei grow very quickly to the size of figs. 19, 20, each of which shows 11 bivalent chromosomes, while in the nucleus represented in fig. 21 there are only 9. In general I have found that the nucleus having 9 chromo- somes is likely to be appreciably smaller than one having 11. Evi- © dently the amount of karyolymph secreted by a nucleus is a function of its number of chromosomes. This is also shown by the many cases of single chromosomes left behind in the cytoplasm and forming small nuclei during reduction, as observed in various forms, especially in hybrids. : These drawings of telophases are nearly all from nuclei which are uncut by the knife in sectioning. The sections are usually 10 # thick, so that in a majority of cases the nucleus is completely contained in one section. The nuclear membrane is conspicuous; hence PY focusing it can be determined with certainty that the membrane is uncut and that the contents of the nucleus are intact. All the nuclei in which counts have been made have been first shown to be intact in this manner. Moreover, whenever the chromosomes in both daughter nuclei could be counted, their sum was invariably found to be 21, whether 10+ 11 or, as occurred in a few cases, 9+ 12: There are a number of interesting features about the telophase, which I have studied with particular care. In the first place it is 10 the best stage for counting the chromosomes with absolute accuracy, and is even better than diakinesis, because of the reduced number of chromosomes. In my last paper on reduction (11) I showed that pairing before the reduction division only takes place to 4 limited extent, and that the shapes characteristic of heterotypic chromosomes are therefore usually absent at this time, as will be seen from figs: 26-34 of the paper referred to. During the period of interkines!> however, the entire chromosomes of the heterotypic mitosis haviS split to form bivalents in which the two parts are closely held together, Wie te. ‘i fa ia ee, eee eet 1909] GATES--CHROMOSOMES IN OENOTHERA 185 show the characteristic X, Y, V, H, K shapes, etc. (See figs. 12-14, 19-21.) A large number of counts of the chromosomes were made in these telophases, and it was found that the numbers 10 and 11 occurred _with approximately equal frequency, while the numbers 9 and 12 were only occasional. Every single case which was admitted as a count could be determined with absolute certainty as a case in which there were, for instance, just 10 chromosomes, no more and no less. In the anaphase of the heterotypic mitosis, the chromosomes as they pass to the poles are nearly globular or somewhat elongated in shape, and are at first closely massed at the poles of the spindle. There is considerable variation in the time of appearance of the split in these chromosomes, though they usually appear bivalent in the early telophase. They appear to come into actual contact at this time, forming a compact group, but never fusing or uniting. They very soon begin to separate, however, and as they do so nuclear sap appears between and to a lesser extent around them. Then the nuclear membrane appears where the karyolymph comes in contact with the cytoplasm. The nucleus so formed is at first very small, but grows rapidly to its full size by the increase in nuclear sap. Lawson (20) has described this process in detail in Passiflora coerulea. He found that the chromosomes fused into a single mass in the telophase, and that the karyolymph begins to be secreted within this chromatic mass and later comes to surround it. The cytoplasm, coming in contact with the karyolymph, forms the nuclear membrane, which is therefore the limiting membrane of the cyto- plasm, just as is the tonoplast of a vacuole. It is undoubtedly true that the nuclear membrane is formed where the karyolymph comes in contact with the cytoplasm, although it must remain uncertain whether the karyolymph is secreted by the chromosomes Or merely attracted and accumulated about them from the cytoplasm. There must be extremely little if any cytoplasm included in the nucleus so formed, because the nuclear membrane appears close about the chromosome group when the chromosomes are still almost in contact. This supports Gricore’s observations (14, 15), that the structural contents of the resting nucleus are formed wholly from the chromo- somes, and there can be no doubt, in this case at least, that the 186 BOTANICAL GAZETTE [SEPTEMBER daughter nucleus is formed entirely from the chromosomes and the karyolymph in which they float. This is to mea strong observational evidence of chromosome continuity. Unlike Lawson’s description for Passiflora coerulea, the chromo- somes in Oenothera certainly do not fuse in the telophase of the heterotypic mitosis, but maintain their separate identity completely at first, and usually more or less completely thoughout the period of interkinesis. Occasionally stages are found which indicate that they string out and anastomose to some extent during a late stage of interkinesis, partly losing their sharp boundaries, but this stage apparently does not very often occur. Nucleoli may be formed de novo in these daughter nuclei, as I have described previously (8, p. 93). The chromosomes in this telophase are all clearly bivalents, in which the halves are closely in contact. I have examined thousands of nuclei in this stage and have never seen the halves other than more or less closely in contact. On the other hand, it is universally true in my observations that no two chromosome bivalents are ever found in contact. Not only is this the case, but they are invariably distributed at approximately equal distances from each other, just within the nuclear membrane. I have never seen an exception to this in any Oenothera studied. The position of the chromosomes might be explained by supposing that they are attached to the nuclear membrane from the first, and are thus carried outward as the nucleus grows.5 In many cases the chromosomes appear actually to be attached to the nuclear membrane, or at least to be lying very closely against it. This, however, leaves unexplained the fact that the chromosomes are never in contact with each other at this time, and further that they are very generally placed at approximately equal distances from each other, just within the nuclear wall. All these facts point to the supposition that the sIt might also be supposed that in the dehydration. processes prepaid : m mounting, the chromosomes would be drawn against the nuclear me in such a case one would undoubtedly find the chromosomes occasionally massed one side of the nucleus or irregularly placed, instead of being always at regular inte vals about the periphery. _ From the regularity of their placing I have no doubt fis the chromosomes occupy their original positions within the nucleus, and there is ° indication that they are ever disturbed by the processes of fixation, imbedding, ee staining, when properly carried out. ; TN 1909] GATES—CH ROMOSOMES IN OENOTHERA 187 chromosome bivalents are mutually repelled. It is true that in the early telophase the chromosomes form a close group, so that they certainly cannot be repelled at that time, but may be attracted. However, the medium in which bodies float frequently changes their qualities of attraction and repulsion, and it appears that the repul- sion first develops after the appearance of the karyolymph in which the chromosomes float. The facts all suggest that the chromosome bivalents mutually repel each other at this time, while the halves of these are held together, probably by attraction. The studies of Witson (37) and others on insect chromosomes show that there are selective attractions between certain chromo- somes at the time of synapsis or at some other period of meiosis. These of course require something more specific than electromag- netic forces to explain them. Fig. 22 shows one of the nuclei of a pollen mother cell in the pro- phase of the homotypic mitosis. Eleven chromosomes are present, _ having the same bivalent structure as in the telophase of the previous mitosis. Both nuclei always go through the various stages of the second mitosis simultaneously. The method of spindle formation has not been studied with great care, but corresponds with the Gladi- olus type of multipolar spindle formation (LAWSON 19, 21). There is no indication of an intra-nuclear network, the spindle being wholly extra-nuclear in origin. A portion of the weft of fibers surrounding the nuclear membrane remains im situ when the latter disappears, forming a close meshwork, against which the chromosomes lie. The fibers then rearrange themselves; the fibrillae from the cones already formed come in and become attached to the chromosomes; finally the spindle becomes bipolar by the rearrangement of the fibers forming the cones. The numerous papers on spindle formation in angiosperms need not be cited here. Among the more recent critical studies of this structure may be mentioned that of BERGHS (2), who insists that the distinction between kinoplasm and trophoplasm will not hold; that the spindle results simply from the gradual orientation of the material of the cytoplasmic reticulum, and returns to a reticulum after mitosis. Sometimes spindle formation begins on one side of the nucleus, as in fig. 23. In such cases the cones of the multipolar spindle may 188 BOTANICAL GAZETTE [SEPTEMBER be formed and the nuclear membrane may have disappeared on one side of the nucleus before any indication of spindle formation has appeared on the other side. Fig. 15 isa polar view of the two homotypic spindles in metaphase. There are 11 chromosomes on one spindle and 1o on the other. Fig. 25 is another at the same stage, showing 10 chromosomes. In fig. 24 the spindles are at right angles and all the chromosomes are not shown. In the side view of the spindle some of the chromosomes appear like tetrads, owing to their bivalent structure. On the homo- typic spindle, before the chromosomes divide, they are very regularly oriented in a single plane in the equatorial plate, as in jigs. 15; 25- This contrasts strikingly with the heterotypic spindle, in which the chromosomes are scattered for a considerable distance along the long axis of the spindle, so that there is usually no metaphase, strictly speaking. Fig. 26 is an early anaphase of the homotypic mitosis, showing one spindle in side view and one in polar view. In the polar view 20 chromosomes are found by focusing through a short distance, and the remaining 2 are found on the next section. In the side view the chromosomes could not all be counted, but presumably there were 20 after division. Two pale-staining nucleoli still persist in the cytoplasm. Fig. 16 shows three of the nuclei in the telophase of the homotyp!¢ mitosis. Many of the chromosomes have a characteristic two-lobed or dumb-bell shape. One chromosome is left behind in the cyto- plasm, leaving ro chromosomes each in two of the daughter nuclel. This two-lobed shape is a characteristic appearance of the chromo- somes in the telophase of somatic mitoses, but presumably bears no relation to the next mitosis, because if this were the beginning of a split for the next mitosis it would indicate that the division of the chromosomes is transverse. But metaphase and anaphase stag® of somatic mitoses show that the chromosomes divide longitudinally. Of course the possibility that the transverse axis of a chromosome in telophase should regularly become its longitudinal axis before the next metaphase, is not excluded, although this seems unlikely. The great difference in the size of the figures made it impossible to arrange them in order on the plates. The magnification is the same OO Se ed eee Ea Lee ere et tena 1909} GATES—CHROMOSOMES IN OENOTHERA 189 as in my last paper in this journal (11), so that the figures can be directly compared. DISCUSSION The history of any ontogeny is the history of the transformation of chemical metabolism into definite structures, or rather the eventua- tion of a series of chemical processes in the production of a series of physical structures. Morphologists and cytologists map the succes- Sion of structures appearing and call it a series of events. They are not unmindful, however, that the primary process is the metabolism, the structures its by-products, which in turn, so far as they are ca- pable of continuing metabolism, produce other structures and, par- ticularly in the adult organism, structures like themselves. Similarly, the chromosomes of the germ nuclei must be thought of as definite aggregations of chemical materials, which initiate or take part in certain forms of metabolism. The chromosomes themselves do not (at any rate not wholly) control their growth or division, but this is more or less subject to the conditions of temperature, etc., in which they are placed, as the work of ERDMANN (7) and others has shown. Similarly, as the complex of physical and chemical conditions in the nucleus and cell undergoes changes, the chromosomes change from the compact to the alveolate or distributed condition, or vice versa, etc. The cytologists who record these events are aware that chemical transformations are continually going on, and that the changes in Visible physical structures are the external concomitant of such chem- ical processes. Chemical reactions in the test tube, however complex, do not lead to the production of any structures more complex than crystals or flocculent masses of various sorts. There are indications that living matter frequently has the properties of liquid crystals, but why do the infinitely more complex reactions of living matter build structures of such relative permanency and of tremendous intricacy? The problem of individual development, from this standpoint, is the ques- tion, How do certain forms of chemical metabolism result in the Production of certain visible physical structures or characters? Of Course, our present microscopic appliances do not permit us to know how many structural steps, if any, there may be between the inter- acting molecular masses and the finest structures visible under our 190 BOTANICAL GAZETTE [SEPTEMBER | highest powers, but it is by no means necessary to assume that there are such. This digression will indicate to some extent, perhaps, the viewpoint of the writer in connection with the cytological aspects of this work. No attempt will be made to discuss here the literature of reduction, only a very few of the recent papers being referred to. The discus- sion of matters of cytological detail will be taken up at another time. One important matter, which was discussed in a former paper (11), concerns the method of chromosome reduction, i. e., whether there is a pairing of threads about the time of synizesis and whether the spirem afterward breaks into a single series or two parallel series of chromosomes. In the paper referred to I established the fact (as will be conceded, I think, after a study of figs. 20-32, particularly, of that paper) that the spirem breaks into a single and not a double chain of chromosomes. The possibility of finding a series of stages which really demonstrates this depends on the shape of the chromo- somes in Oenothera. They are relatively short and thick, like many animal chromosomes, and quite unlike the twisted and tangled chromosomes of such forms as Lilium, whose relationships are 5° difficult to interpret. It is a curious fact that so many of the critical studies on reduction in plants have been made on forms with long narrow chromosomes, although many of the interpretations of critical stages can be made with much greater ease and certainty on forms having short and stout chromosomes. In the paper just referred to, I concluded that the method was probably different in different genera, there being a side-by-side pairing of threads in some forms (parasynapsis),° but an end-to-end arrangement of the chromosomes to form a single spirem (telo- synapsis)° in other forms. Subsequent papers by various invest- gators continue to describe both these methods, and the evidence 9 certain cases is so clear that I think there can remain no doubt that both these general methods occur in plants. MONTGOMERY concluded in 1898 (26) that there are different types of reduction in animals. In a recent study of Fucus, Yamanoucut (39) shows clearly that at the time of reduction the ragged nuclear reticulum is gradually transformed into a single continuous thread, which enters into 6 These convenient terms follow the usage of Witson (36). 1909] GATES—CHROMOSOMES IN OENOTHERA IQI synapsis. This thread then becomes rearranged into regular loops converging to one side of the nucleus and forming the “bouquet” stage of E1sEN (6). This stage is characteristic of many animals, in which it has been described by JANSSENS and DuMEz (17), STEVENS (34, 35), MARECHAL (25), and JorDAN (18), to mention only a few. Each loop is composed of two chromosomes arranged end to end. Similarly the spirem in Fucus is made up of the maternal and paternal chromosomes arranged endwise in a single thread. This is what I have shown to be the case in Oenothera (11), although Oenothera has no typical “bouquet” stage, nor has any other angiosperm, so far as I am aware, though the second contraction phase, character- istic of various forms, probably corresponds to it. OVERTON (30) states that this stage does not occur in the plants with short chromo- somes which he has examined, yet it occurs in Oenothera, in which the definitive chromosomes are very short and frequently almost globular. The second contraction phase is a well-marked stage of meiosis in Oenothera. I may mention a few of the recent accounts involving an end-to- end arrangement of the chromosomes to form the spirem (telo- synapsis). Morrtrer finds (29) that in Podophyllum, Lilium, and Tradescantia the two members of each bivalent chromosome were not side-by-side in the spirem, representing the halves of the longi- tudinally split thread, but were arranged end-to-end in the chromatic thread. Lewis (22), in a study of Pinus and Thuja, finds no pairing of threads, but cross-segmentation of a single post-synaptic spirem to form the chromosomes. Just what relation his fig. 15, which indi- Cates a reticulum as occurring about the time of chromosome forma- tion, bears to the other stages, it is hard to say. Lewis ventures the Opinion that the second division is probably qualitative, but with a manifest lack of evidence to support it. SCHAFFNER (33), in Agave, nds bodies which he believes are bivalent prochromosomes, and a Single spirem which segments to form the twelve bivalent chromo- somes. Among very recent accounts of reduction which involve a longi- tudinal pairing of threads (parasynapsis) may be mentioned that of Grécore (16), with figures involving the critical stages in Lilium, smunda, and Allium; YAmMaNoucut (38) in Nephrodium; OVER- 192 BOTANICAL GAZETTE [SEPTEMBER TON (30) in Thalictrum, Calycanthus, and Richardia. ALLEN’S extensive earlier paper on Lilium (1) should also be mentioned. Although, in such cases as Lilium, both accounts of reduction are given for the same form by different authors, yet the evidence from such forms as Nephrodium on the one hand, and Tradescantia, Oenothera, and Fucus on the other hand, makes it very difficult to deny that both methods occur. A comparison of a wide range of forms whose reduc- tion phenomena show many differences, will doubtless lead finally to an explanation of the nature and meaning of these differences. It is very evident that the time has passed when all the accounts of reduction in plants can be brought under a single scheme. The task of the future will be to interpret the meaning of the differences observed in various forms. Are they matters merely of cell mechanics, or are they related to hereditary processes? It is not impossible that correlations will be found between the method of reduction in an organism and its type of hereditary behavior. In other words, the phenomena of reduction and the distribution of elements during meiosis may condition to some extent the hereditary behavior of a plant or animal. This is already known to be the case with sex in insects. But it does not seem worth while entering into such theoret- ical possibilities on the basis of our present knowledge. The fact that in this Oenothera hybrid the number of chromosomes in the pollen mother cells is the sum of those which enter the fusion nucleus at the time of fertilization, is to me clear evidence that each chromosome in the germ cells is the genetic descendant of one of the chromosomes in the fertilized egg. The work of various investigators seems to have established the genetic continuity of chromosomes from generation to generation of individuals. ‘The manner in which the chromosomes are distributed during reduction in this Oenothera hybrid clearly shows that they behave as individuals at this time. Witson’s recent account of the supernumerary chromosomes ei Metapodius (37), a genus of Hemiptera, shows certain points © resemblance to the condition in Oenothera. WILSON finds that certain chromosomes (the idiochromosomes) may be present in duplt cate, or may even have several representatives in the cells of certain individuals, which nevertheless show no external difference> ” number of chromosomes being fixed for any individual, but vary 1909] GATES—CHROMOSOMES IN OENOTHERA 193 in different individuals from 21 to 28 according to the number of supernumerary chromosomes present. The distribution of the super- numeraries during spermatogenesis is also irregular, so that the num- ber varies in the different sperm nuclei of an individual. Occasional irregularities in the distribution of idiochromosomes during reduction were observed in the form having 22 chromosomes, both idiochromo- somes passing to the same cell. This is believed to be the origin of _ Ue variation in different individuals, the supernumeraries being | merely duplicates of the idiochromosomes. Similarly, I have observed occasional irregularities in the chromo- some distribution during reduction in nearly all the mutants of _ Oenothera examined, and this doubtless accounts for the different _ humbers of chromosomes found in different individuals, the extra chromosomes being duplicates of others already present, and the presence of 20 chromosomes in one individual of O. lataXO. gigas being due to the absence of one chromosome from one of the germ cells Which produced that individual. _ Montcomery (27) first proposed the theory that in synapsis homologous chromosomes of maternal and paternal origin pair with each other, and much subsequent work, especially with animal chromosomes, sustains that view. As I have already shown, pairing of Oenothera chromosomes frequently fails to take place, and this allows a chance for the irregularities in chromosome distribution 4 Which occur. Boverr (3, p- 54) has suggested that when there is an _ absence of pairing in synapsis in any organism, its chromosomes are hereditarily equivalent. In Oenothera there is clearly a tendency to pair, but it is only partly carried out. I have already compared (11, _ P- 25) the behavior of the chromosomes in this hybrid with the con- 7 dition described by ROSENBERG (31) in the Drosera hybrid having o+20 chromosomes. The method of segregation of chromosomes _ In the heterotypic mitosis is evidently different in the two hybrids, 4nd this was used as an argument in favor of a different method of Teduction in the two cases. In the Oenothera hybrid the 10-11 Segregation shows that the segregation cannot be between chromo- Somes of maternal and paternal origin, but it must be remembered _ im this connection that the 14 paternal chromosomes are very prob- a ably a double set of 7 O. Lamarckiana chromosomes. The regu- 194 BOTANICAL GAZETTE [SEPTEMBER larity with which the ro-rz segregation takes place, indicates that it is not merely a matter of chance, but that some mechanism, perhaps connected with the spindle, determines this regularity. A study of later generations of this hybrid should throw much light on the ques- tion whether the chromosomes of Oenothera are really unlike. Morcan (28) has recently shown that in certain phylloxerans, in which a generation of winged individuals produces (partheno- genetically) sexual males and females, the eggs are of two kinds, the female-producing eggs being large and the male-producing eggs small. Further, the females thus produced have the same number of chromosomes as the parthenogenetic females, while the males have two chromosomes less. Thus, in the formation of the polar body of the male egg, two extra chromosomes are extruded, so that the somatic cells of the male contain two less chromosomes than those of the female. Evidently there is here some sex-determining factor which antedates the chromosomal differences with the two kinds of eggs, and yet the chromosomes are the instruments of this factor, for the extrusion of the two chromosomes always precedes the develop- ment of the male individual. Studies of this sort will doubtless g!v° us clearer notions regarding the respective réles of chromosomes and cytoplasm in heredity. : In a former paper (11) I suggested that if the chromosomes of Oenothera are unlike in their hereditary capacities, then the occa- sional irregularities I have described in the chromosome distribu- tions on the heterotypic spindle would furnish a possible basis for the appearance of a series of types, such as the mutants of O. Lamarckian4. I have since studied the reduction phenomena in O. biennis an other types, an account of which will be published later. O. biennt’, in at least some of its geographical races, appears to be stable und ef ordinary conditions, though MacDouGat (24a) has obtained atypl@ forms by injections into its ovaries. The loose and frequently unpaired arrangement of the chromosomes in the central region. of the heterotypic spindle is evidently a delicately adjusted condition which can easily be thrown out of balance. Yet in some way te balance is ordinarily maintained and is only occasionally deranged in such a way that a different chromosome distribution results. It = not impossible that the condition of mutation in O. Lamarckian4 ER TT a eee ee ee Re, Oe et 2 aves) ee? ee) ea ws Cee, BSEe, ree IPE ego mee Rae Ae Phe ey re OM RET CVE S See ea oh ho PP ee, Se ee Ae ee Ps ee epee hemot, Wp a, Fran we ee as ee ae ‘eet eet ae i 1909] GATES—-CHROMOSOMES IN OENOTHERA 195 has arisen through a disturbance by some means of this delicate con- dition of balance. 5 But it is useless to speculate on such possibilities until it is known _ whether the chromosomes of Oenothera are really unlike, and at present there is no evidence in favor of this view except the inferential evidence from chromosomes in general. The fact that chromo- somes reappear with each mitosis, showing the same differences where visible differences exist (except in the cases of amitosis, whose _ Status in relation to hereditary processes is not at present understood), _ would seem to favor the assumption that they maintain their identity _ and are unlike. But I need not cite here the general arguments in _ favor of this hypothesis. ‘The more definite evidence, such as that of the sex chromosomes in insects, is not necessarily of universal applica- tion. SUMMARY 1. O. lataXO. gigas has 21 chromosomes in its somatic cells, 7 of maternal origin (O. /atd) and 14 of paternal origin (O. gigas). In one individual the number was 20, owing probably to the absence _ of one chromosome from one of the germ cells which produced this individual. 2. These chromosomes segregate at the time of reduction, so that in individuals having 21 chromosomes half the germ cells receive 10 and half 11 chromosomes. In the individual having 20 chromosomes, Io enter each germ cell. Occasionally one chromosome goes to the _ Wrong pole of the spindle, so that in plants having 21 chromosomes a few germ cells are found having 9 or 12 chromosomes and in the plant with 20 chromosomes, occasional germ cells have 9 or 11 Rade etre Mipkyes 8 } ion accounts chromosomes. This irregularity in d for the fact that different individuals in a race in some cases have different numbers of chromosomes. 3. The 10-11 segregation of chromosomes in the formation of the 8erm cells of this hybrid shows that there is not here a pairing and S€paration of homologous chromosomes of maternal and paternal Origin, but that the segregation tends to be into two numerically _ €qual groups. Bir ee ~< 4. Evidence from this and other work shows that there are two general methods of chromosome reduction in plants, one involving 196 BOTANICAL GAZETTE [SEPTEMBER a side-by-side pairing of chromatin threads (parasynapsis) to form a double spirem; the other involving an end-to-end arrangement (telosynapsis) of the maternal and paternal chromosomes to form a single spirem, which may afterward split longitudinally. 5. The behavior of the chromosomes in Oenothera supports the view of their genetic continuity from generation to generation, the number present in any individual being always the sum of the chromo- somes in the germ cells from which that individual was formed. 6. If the chromosomes of Oenothera are unlike in their hereditary capacities their behavior furnishes a not improbable basis for the phenomena of mutation in Oenothera Lamarckiana. But it remains to be proven that the chromosomes of Oenothera are of unequal hereditary value. THE UNIVERSITY OF CHICAGO LITERATURE CITED 1. ALLEN, C. E., Nuclear division in the Aspe mother cells of Liliwm canadense. Annals of Botiaty 19: 189-258. pls. 6-9. 1905. . Bercus, J., Le fuseau hétérotypique de Paris quadrifolia. La Cellule 22: 203-214. pls. 2. 1 Boveri, T. echuie iiber die Konstitution der chromatischen Substan? des Peltier, pp. 130. figs. 75. Jena. 1 d , Zellen Studien V. Ueber die Abbingigkeit der Kerngrésse uD Zellenzahl des Seeigel-Larven von der Chromosomenzahl der Ausgangszellen. pp. 80. pls. 2. figs. 7. Jena. 5. DeVries, H., Bastarde von ecahien gigas. Ber. Deutsch. Bot. Gesells. 26a: 754-762. 1908. . Etsen, G., Speimstogenesis of Batrachoseps. Journ. Morph. 17: i pls. 14. 1900. ErpMANN, R., Experimentelle Untersuchung der Massenverhiltnisse vo? P a, Kem, und Chromosomen in dem sich entwickelnden Seeigelei. Arch. Zellforsch. 1:76-136. 1908. ee 8. Gates, R. R., Pollen development in hybrids of Oenothera lata XO. Lama kiana, and its feisGen tomutation. Bor. GAZETTE 43:81-115- pls. 2-4- er , Hybridization and germ cells of Oenothera mutants. Bot. GazeTTe i) Y a i 44: 1-21. figs. 3. 1907. ; vt 10. e chromosomes of Oenothera. Science N. S. 27: ease Ir s study of reduction in O¢enothera rubrinervis. BOT 46: sag pls. 1-3. 1908. yon . GEerTs, J. M., Beitrage zur Kenntnis der cytologischen Entwicklung Oenothera Pomatchlen Ber. Deutsch. Bot. Gesells. 26a:608-614- * Lal N Cth eee eee eee 1909] GATES—CHROMOSOMES IN OENOTHERA 197 13. al eS Leal un 4 ~J 24. Geerts, J. M., Beitrige zur Kenntnis der Cytologie und der partiellen Ster- ilitat von Oenothera Lamarckiana. Recueil Trav. Bot. Néerl. 5:93-208. pls. 5-22. 1909. . Grécorre, V., ET Wycaerts, A., La reconstruction du noyau et la formation des chromosomes dans les cinéses somatiques. La Cellule 21:7-76. pls. . Grécorre, V., La structure de l’élément chromosomique au repos et en divi- sion dans les cellules végétales (racines d’Allium). La Cellule 23: 311-353. jigs. 3. pls. 2. 1 6. go , La formation des gemini hétérotypique dans les végétaux. La Cel- lule 24: 369-420. = 2: 1907. . Janssens, F. A., Et Dumez, R., L’élément nucléinien pendant les cinéses de maturation de sperinadagtes chez ee attenuatus et Pleto La Cellule 20: 421-460. pls. 5 - Jorpan, H. E., The abe aie asi oe A pops Mayeri. Carnegie Institu- tion Srp 102. pp. 13-36. pls. 1-5 . Lawson, A. A., Origin of the cones of multipolar spindle in Gladiolus. Bor, Gazetre 30: 145-153. pl. 12. 1900. ———.,, On the relationships of hs nuclear membrane to the protoplast. Bor. Gazette Sg 305-319. pls. 1903. , Studies in spindle msde Bot. GAZETTE 36:81-100. pls. 15, 16. 1904. . Lewis, I. M., The behavior of the chromosomes in Pinus and Thuja. Annals of Botany 22: 529-556. pls. 29, 30. 1908. . Liu, F. R., Observations and experiments concerning the aero | piece of embryonic development in Chaetopterus. Journ. Exp. 3°153-268. pl. r. figs. 78. 1906. Lutz, ANNE M., Notes on the first generation hybrid of Ocenothera latax O. gigas. Science N. S. 29: 263-267. 1909. 24a. MacDovuaeat, D. T., Vari, A. M., AND SHULL, G. H., Mutations, variations, i] Oo a) ° and relationships of the Oenotheras. Carnegie Institution Publ. 8. pp. 92. pls. 22. figs. t MarécHar : “fur es 76 ese des Sélaciens et de quelq utres Chordates. i ka Cellule 24: 7-239. pls. I-II. 1907. . Montcomery, T. H., The spermatogenesis in Pentatoma up to the formation of the spermatid. Zool. Jahrb. Anat. Ont. r2/1-88. pls. 1-5. 1 ——., A study of the chromosomes of the germ cells of Metazoa. "Trans. Amer. Phil. Soc. 20: 154-236. pls. 4-8. 1901. - Morcan, T. H., Sex determination = a in phylloxerans and aphids. Siienes: N. S. 29: 234-237- - Morrter, Davip M., The bainedeihis tig the heterotypic chromosomes In pollen thother cells. Anas of Botany 21: 309-347: pls. 27, 28. 1907- - Overton, J. B. On the organization of the nuclei in the pollen mother cells of certain plants with especial reference to the permanence of the o- Somes. Annals of Botany 23:19-61. pls. 1-3. 1909- 198 BOTANICAL GAZETTE [SEPTEMBER 31. ROSENBERG, O., Ueber die Tetradentheilung eines Drosera-Bastardes. Ber. Deutsch. Bot. Gesells. 22: 47-53. pls. 4. 1904. 32. ———, Cytological studies on the apogamy in Hieracium. Botanisk Tids- skrift 28: 143-170. figs. 13. pls. 1, 2. 33. SCHAFFNER, JoHN H., The fe daciioe Bvisinn in the 2 of Agave virginica. Ren GAZETTE 47: 190-214. pls. 12-14. 9. 34. Stevens, N. M., Studies in spermatogenesis, with special Bes to the accessory chromosome. Carnegie Institution Publ. 36.% pp. 32. pls. 7. 1998. : omparative study of the heterochromosomes in certain species of eee Hemiptera, and Lepidoptera, with especial reference to sex deter- mination. Carnegie Institution Publ. 36.2 pp. 33-74. pls. 8-15. 1906. . Witson, E. B., Studies on chromosomes. IV. Journ. Exp. Zool. 6:84. 1909. w an , Studies on chromosomes. V. The chromosomes of Metapodius. Journ. ‘ey: Zool. 6: 147-205. pl. r. figs. 13 38. YAMANOUCHI, SHIGEO, Sporomeesis i in S ceecoatew. Bor. GAZETTE 45:1- 30. pls. 1-4. 1908. , Mitosis in Fucus. Bot. Gazette 47:173-197. pls. 2-11. 1909- EXPLANATION OF PLATES XII-XIV The figures were drawn with the - of a Bausch & Lomb camera anda Zeiss apochromatic objective 2™™, an. 2. particular care being taken to ere the chromosomes accurately. The ‘etic in plate XII were drawn W! ye Zeiss compensating ocular 12, those of plates XIII and XIV with ocular 18. : are reduced one-fourth in reproduction, which leaves the figures in plates ae and XIV magnified as in my last paper (11) on reduction. PLATE XII All figures from the plant having 20 chromosomes. cells Fic. 1.—Early telophase of the heterotypic mitosis in the pollen mother t: before formation of the nuclear membrane; 10 chromosomes, all ae bivalen in many the halves are dumb-bell sha at Fic. 2.—Same stage; 11 chromosomes, many irregular; 9 chromosomes the opposite end of this spindle; dark staining bodies in saicbeed of cytoplas™- Fic. 3.—Telophase, showing 10 chromosomes of various shapes. pe a 4.—Telophase, showing 10 chromosomes, most of them clearly bivalen eicsne f their is. 6.—Telophase, downs rr chromosomes, with no indication © Bs bivalent character; 9 at opposite end of spindle; apparent size of chrom in all figures varies to a certain extent according to the depth of stain. pee Fics. 7, 8.—Later telophases, soon after formation of nuclear membrane, showing 10 chromosomes. ddle FIGs. 9, 10.—Metaphase groups of chromosomes in somatic cells from ™! layers of anther wall, each showing 20 chromosomes; indications of a” asi ment of the chromosomes in pairs. ® BOTANICAL GAZETTE, XLVIII PLATE XII GATES on CHROMOSOMES of OENOTHERA NOTANICAL GAZETTE, XLVIII PLATE XIII GATES on CHROMOSOMES of OENOTHERA MeMOFANICAL GAZETTE, XLVIII PLATE XIV GATES on CHROMOSOMES of OENOTHERA 1909] GATES—CHROMOSOMES IN OENOTHERA 199 PLATE XIII Figures in plates XIII and XIV from plants having 21 chromosomes; not numbered in developmental order. Fic. 11.—Heterotypic spindle in side view, showing 20 or 21 chromosomes, not forming an equatorial plate, but loosely aggregated in the median region of the spindle; cf. fig. 15. ; Fic. 12.—Telophase of heteroptypic mitosis, showing both daughter nuclei; one, uncut, shows 10 chromosomes. Fic. 13.—Telophase, showing 11 chromosomes and a number of very small nucleoli; an unusual condition, probably due to the failure of the nucleoli to fuse at an earlier stage. Fic. 14.—Telophase, showing 12 bivalent chromosomes, lying closely against the wall, tipped at various angles to the plane of view, which gives them a variety of appearances; an exceptional case, in which one chromosome too many has passed to the end of the spindle; 9 at opposite end; 2 nucleoli. Fic. 15.—Metaphase of homotypic mitosis in polar view, showing equatorial plates of chromosomes, 10 chromosomes on one spindle and 11 on the other; ef. fig. rr. PLATE XIV ; Fic. 16.—Telophase of homotypic mitosis, showing three daughter nuclei; one chromosome left behind in the cytoplasm, leaving 10 chromosomes each in two of the daughter nuclei; many chromosomes show characteristic dumb-bell shape. Fics. 17, 18.—Very early telophase of the heterotypic mitosis, just after the nuclear membrane has been formed around the daughter nuclei; one shows to bivalent chromosomes, the other 11. Fics. 10, 20.—Telophases, each showing 11 bivalent chromosomes. Fic. 21.—Telophase with 9 chromosomes only. Fic. 22.—Prophase of the homotypic mitosis, showing 11 bivalent chromo- somes, which have th pr in the previous telophas ; nuclearmem- brane just broken down, its position still occupied by a weft of fibrillae, against which the chromosomes lie; cones of the multipolar spindle forming. eae Fic. 23.—Same stage as fig. 22; a less common condition, in which spindle formation begins on one side of the nucleus; 10 chromosomes, only a few of which show bivalent character. is MEE _ Fic. 24.—Metaphase of the homotypic mitosis, showing one spindle in side view and the other in polar view; chromosomes not all shown. __ Fic. 25.—Equatorial plate of homotypic spindle, showing 10 chromosomes in a single plane, few showing their bivalent character. es 1G. 26.—Early anaphase of homotypic mitosis, after division ine babl Somes; one spindle in side view, showing only part of the chromosomes agamersed 20 in all); the other spindle in polar view, showing 20 chromosomes (two more 8 "5 this spindle in the next section); 2 nucleoli in the cytoplasm near Spindles, THE DEVELOPMENT OF THE EMBRYO SAC OF SMILACINA STELLATA F. McALLISTER (WITH PLATE XV) The object of this paper is to describe the development of the embryo sac of Smilacina stellata (L.) Desf., with a view to its pos- sible bearing on the current interpretations of the lily type of embryo sac. : In 1880 TrEUB and MELLINK (27) reported that in Lilium bulbi- ferum and in Tulipa Gesneriana the embryo sac mother cell develops directly into the embryo sac without any previous divisions. In 1884 GUIGNARD (11) and also STRASBURGER (24) called atten- tion to the fact of a reduction of the number of the chromosomes during the development of the germ cells of angiosperms. STRAS BURGER (25) further pointed out in 1888 that in the case of the embryo sac in certain orchids and in Allium, the reduction of the number of the chromosomes occurs in the nucleus of the embry? sac mother cell. It was further established simultaneously by OVERTON (16) and GurGNaRD (12) that, in the lilies and other plants in which the embry° sac mother cell develops directly into the embryo sac without previous division, reduction takes place in the nucleus of the young embry? sac. The natural conclusion from these discoveries is that the yours embryo sac in these cases is the morphological equivalent of a pollen or embryo sac mother cell. That the nuclei resulting from the first two divisions in the embryo sac of the lilies are morphological equiv lents of the microspores is strongly suggested by these results. STRASBURGER (26) in 1894, discussing the formation of the a sac of the lilies, concludes that the cell in which the reductio? 0. the chromosome number takes place is to be regarded as 4 mother cell and not simply as a young embryo sac, since in the ovaries ° Allium and Helleborus he had found that the reduction of vd chromosomes takes place in the embryo sac mother cell before. sags * Botanical Gazette, vol. 48] aa 1909] MCALLISTER—EMBRYO SAC OF SMILACINA 201 undergone division. He concludes that in these cases the course of development is abbreviated, so that there is no formation of reduced cells which are to be immediately absorbed, as is the case in many other species. According to this view the heterotypic and homeotypic divisions are transferred to the early stages of development of the gametophyte. The term “macrospore” or “megaspore” is frequently loosely used by the supporters of this view in reference to the cell which develops into the embryo sac, whether it be the young embryo sac itself, or one of the daughter cells, or one of four granddaughter cells which have been formed by the reduction divisions. From the evident homology of the nuclei of the first two divisions of the embryo sac mother cell of the lilies with the microspores, as Suggested by the discoveries of GUIGNARD, STRASBURGER, OVERTON, and also later investigators, the obvious interpretation of their nature is that they are megaspores. According to this view the reduction divisions may be regarded as the sole criteria of spore formation. STRASBURGER (26) further says, in reference to the significance of the number of divisions which intervene between the embryo sac mother cell and the completed embryo sac, with its egg: “That the number of these intervening divisions is not of primary importance is Proved by the fact that the number is not always the same: thus in Lilium and Tulipa there are but three; in Ornithogalum, Com- melyna, and species of Agraphis, there are four; in yet other cases the number jis greater than five. ... . ” Smilacina stellata, the species which I have studied, is a member of the order Convallariaceae. The data as to the morphological relation- ships of the genus Smilacina are scanty and in part contradictory. The order Convallariaceae is retained by ENGLER and PRANTL under the sroup Asparagoideae, but the nature of the relationship of the group 'o the other orders of the Liliales is not very clear. The other mem- bers of the Convallariaceae whose embryo sac development has been Studied are Convallaria, Paris, and Trillium. Convallaria majalis has been investigated, as to the development of its embryo sac, by WIEGAND (29). He reports that the embryo ‘ac mother cell divides to form two fully separated daughter cells, the outer of which is the larger. The nuclei of both of these cells 202 BOTANICAL GAZETTE [SEPTEMBER undergo a second division, but this time no cell walls are formed. The resulting four nuclei again divide, and the partition wall between the two sets of nuclei disintegrates enough to allow a nucleus from the lower set to pass through and unite with one from the upper set. This fusion nucleus is the endosperm nucleus. If this account is correct, we have at least a partial absorption of a cell wall in the formation of the embryo sac and the utilization of all four nuclei of the double division, as will be described below for Smilacina stellata. WIEGAND’s account is contradicted, however, by SCHNIEWIND- Tutes (21), who reports that in Convallaria majalis the mother cell divides to form a row of four cells, one of which develops into the embryo sac, while the other three disintegrate. As a possible explana- tion of the difference which exists between her account and WIE- GAND’s, she remarks that’ greenhouse material rarely shows normal development. WrEGAND, however, does not mention the use of such material in his investigation. That both Wrecanp and SCHNIE- WIND-THIES are correct is possible, but not very probable. It 1s very much to be desired that this species be reinvestigated to clear up this confusion. ERNST (9) reported that in Paris quadrifolia the lower of two daughter cells develops into the embryo sac. The upper daughter nucleus divides once, but the resulting nuclei degenerate. In the same paper he reports that the lower of two daughter cells of T rillium grandiflorum develops into the embryo sac. The upper daughter cell is smaller from the first and rarely divides. For T. recurvatum, OP the other hand, CHAMBERLAIN (6) has reported that the embry° sac develops from the lower of four megaspores. Though scanty, the literature on the order Convallariaceae pes to suggest that there exists in the group great variation in the condu of the cells and the nuclei resulting from the reduction divisions, an | that we may here find transition conditions between the normal type of embryo sac formation and that found in the lily. The materials for this study were collected in the vicinity of Be Wis., in May 1906 and 1907, in November 1907, and in June uae Flemming’s strong solution gave the best fixation for the early at but worked badly for mature embryo sacs. With these ™ ee embryo sacs the following chromacetic fixative gave good res oit, 1909] MCALLISTER—EMBRYO SAC OF SMILACINA 203 chromic acid 0.7%, glacial acetic acid o.5°°, water 100°°. A fixative composed of two parts absolute alcohol and one part glacial acetic acid gave very good results also. Flemming’s weak solution was not tried. Smilacina stellata is especially favorable for obtaining a complete series of stages of the early development of the embryo sac. The flowers, eight to fourteen in number, are borne in a raceme, which does not expand till the embryo sac has nearly reached the eight- celled stage. It is therefore possible to cut an entire’ raceme longi- tudinally and get a maximum number of ovules cut parallel to their long axes. The oldest flowers are at the bottom. Each flower con- tains five to seven ovules, and about seventy racemes were cut in paraffin. ; i In the material collected November 16, the nucellus was only partly developed in the lower flowers of the raceme. There were no mother cells to be distinguished in any of this material. Material collected May 7 showed, in a few shoots, mother cells in the synapsis stage in the lower flowers, while at the top of the shoot the nucellus was barely differentiated. Most of the racemes taken at this date Were farther developed: than those mentioned above, the younger flowers being at least in the synapsis stage. The mother cell is located at a variable depth beneath the surface of the nucellus. Not uncommonly it is immediately beneath the epidermis (fig. 1). In other cases it is separated from the epidermis by one cell layer. Most commonly two cell layers intervene (fig. 2). Measurements of several camera drawings of the mother cell at the Synapsis stage gave an average breadth of 22 #, and an average length of 30 Bb. ’ I shall not here take up in detail the question of the reduction of thechromosomes. In the first division of the mother cell, thick double chromosomes, characteristic of the metaphases of the heterotypic division, appear (fig. 3). The number of bivalent chromosomes, as shown in the anaphase stage of this division, is twelve. The ‘porophytic number, as shown by root tip cells, is twenty-four. - A definite cell plate, and in most cases a cell wall, is formed, Separating the two daughter nuclei of the first division before the ‘econd division takes place (figs. 4, 5). The cell plate is formed by 204 BOTANICAL GAZETTE [SEPTEMBER the thickening of the connecting fibers in the equatorial region to form a septum which separates the cells. This splits in the central region first, and often a thin layer of orange staining material is to be seen between the split layers. The plasma membranes formed by the splitting of the cell plate are made very conspicuous in cells in which there is a slight plasmolysis. The cell wall seems in most cases to be fully formed before the second division is completed. Several preparations were found in which the wall seemed to be incomplete after the second division (jig. 7). These, however, may represent a stage in the removal of the cell walls, as described below. In many cases the wall of the first division is transverse, but not infrequently it is oblique (figs. 4, 12). The walls formed in the second division are extremely variable as to their position. F requently (fig. 11) they are transverse, forming a linear row of four cells. Very often the outer daughter cell divides longitudinally and the inner transversely (jig. 8). Less frequently, the outer divides trans- versely and the inner longitudinally (jig. 6). Fig. 7 shows an arrange ment which is occasionally met with, both daughter cells having divided longitudinally. Rather frequently one section shows two cells divided transversely, while the next succeeding section shows two cells divided longitudinally (figs. 9, 10). This arrangement could only result from the division of the mother cell at first by 4 longitudinal wall parallel to the plane of the section, and the division of one of the daughter cells by a transverse wall and of the other by @ longitudinal wall. This case is easy to recognize when the plane ° the section is such that both of the cell boundaries of the second division are vertical. It is much more difficult to recognize when one of the cell boundaries of the second division lies in or near the plane of the section. Such a mode of division is of course frequently found in pollen mother cells. Fig. 12 shows, however, by far the most common arrangement of the cells, in which the first wall * oblique and the walls of the dividing daughter nuclei are approxr mately at right angles to it. ‘ Most of these various arrangements of the four cells resulting _ from the division of the embryo sac mother cell have been desct! by other authors, but in the stages immediately following We ut ze ~~ 1909] MCALLISTER—EMBRYO SAC OF SMILACINA 205 confronted with a series of changes leading to a method of embryo sac formation quite different from any which has been hitherto described. The cell walls which separate the four megaspores break down and disappear. Immediately following the formation of four fully separated daughter cells and nuclei (figs. 8, rz) we find a stage in which the same four nuclei are seen occupying a large cell with no traces of cell walls separating them (fig. 14). The evidence of the disappearance of the walls between the megaspores is not based on scattered examples, selected from a large number of specimens, but on a large number of continuous series of stages taken from a single inflorescence. Fig. 11 shows four cells fully separated by cell walls, while in the next older flower on the same shoot are found four nuclei in a common cavity (fig. 14). In fig. 13 the cell walls formed by the second or homeotypic division have entirely disappeared, while a slight but distinct cleft, extending across the cell, shows the location of the wall formed between the nuclei in the first division. A statistical examination of a number of racemes to determine the exact stage of development of the mother cell or its products in each ovule, gave very conclusive evidence of the continuity of these series. The following is a fair example of an average shoot of the proper age. In this shoot of nine flowers the youngest flower had mother cells in a stage later than synapsis. The next older flower contained mother cells in the prophase and metaphase stages of the first division. The third showed in one ovule a heterotypic anaphase stage, and the other ovules showed the heterotypic telophase snide The fourth flower showed the earlier stages of the second or homeotypic division. The fifth contained daughter nuclei of the second division In the telophase stage, and the sixth showed nuclei of this division Separated by cell walls. The next older flower showed in a part of ts ovules the four nuclei still separated by cell walls, while the rest of its ovules showed little or no trace of cell walls between the four nuclei. The ninth flower, the oldest on the raceme, showed four- celled embryo sacs in all its ovules, with no traces of cell wall separat- ing the nuclei. The series here described shows no trace of the Stowth of one megaspore at the expense of the other three, or of the 206 BOTANICAL GAZETTE: [SEPTEMBER first and second divisions of such a megaspore to form a four-celled embryo sac. We must conclude, therefore, that the walls between the four megaspores break down, and their nuclei become the first four nuclei of the embryo sac. In the succeeding stages there is a continuous growth of the nuclei resulting from the reduction divisions and of the embryo sac formed from these nuclei. Very soon after the cell walls have disappeared from between the reduction nuclei, vacuoles begin to appear in the young embryo sac. Figs. 15, 16, 17 illustrate the gradual enlarge- ment of the cell containing the four nuclei, and the appearance of vacuoles in the cytoplasm. The vacuolization more than keeps pace with the enlargement of the embryo sac, and finally the separate vacuoles unite to form one large centrally located vacuole. It is at about this stage of growth that the third division takes place, forming the eight nuclei of the complete embryo sac (fig. 17). The embryo sac still continues to enlarge. The nuclei remain unchanged for a relatively long period. The polar nuclei come together and lie in contact during this period of quiescence, but are seen to be fused before the cells in the micropylar region show any signs of differentia- tion to form the egg apparatus. Not until nearly time for pollination is there any rearrangement of these cells, which are to form the egg apparatus. When finally differentiated ‘the synergids are pear-shaped and faintly striated. The egg is somewhat larger than the synergids, and usually has a large vacuole in the basal region. It stains less heavily than the synergids. I shall not here discuss the formation of the cell boundaries of the synergids and the egg. The antipodal ney are smaller than the others, and usually occupy a constricted regio” at the lower end of the embryo sac. These antipodal nuclei at stage often number more than three, and in such cases are usually separated by division walls. : The most natural interpretation of the phenomena just described is that the first four cells formed by the division of the embry° - mother cell are megaspores, and that these four spores jointly com bine to form one embryo sac. It would seem that this assump? is the only one possible, for before the division membranes disap 2: the four cells conform to all the criteria for spores in other similar 1909] MCALLISTER—-EMBRYO SAC OF SMILACINA 207 cases, and the mere loss of the division membranes cannot affect their morphological value. Some preliminary studies of Smilacina racemosa seem to show that the two outer nuclei, formed in the double division of the embryo sac mother cell, undergo two further divisions to form the eight nuclei of the mature embryo sac. I shall describe this species, with other related species, more fully in a later paper. Recent studies have brought to light an increasing number of so-called atypical methods of embryo sac formation, which must be considered in attempting its phylogenetic interpretation. In Eichhornia, according to SmirH (22), a cell plate is rarely formed between the two nuclei resulting from the first division of the embryo sac mother cell, and a cell plate is also rarely formed between the daughter nuclei of the second division. Reduction takes place and one of the four megaspores forms the embryo sac. CAMPBELL (2, 3) reported the discovery of the 16-nucleate embryo sac of Peperomia pellucida, and in the following year JOHNSON (13); working independently, published an account of the same species. The embryo sac mother cell develops directly into the embryo sac. The sixteen nuclei organize to form an embryo sac with an egg apparatus Consisting of an egg and one synergid. Six nuclei are cut off singly around the periphery of the embryo sac, and the remaining eight nuclei fuse to form the endosperm nucleus. Later JOHNSON (14) reported that in Peperomia hispidula fourteen out of the sixteen nuclei of the embryo sac unite to form the endosperm nucleus. In contrast with the large number of nuclei in the embryo sac of Peperomia, is the embryo sac of Helosis guayanensts, which es reported by CHopat and BERNARD (7) to contain only four nuclei when mature. This 4-nucleate embryo sac is due to the disintegra- hon of the lower nucleus of the first embryo sac division, so the prod- ucts of the division of the upper nucleus alone enter into the embryo Sac structure. Avena fatua has been shown by CANNON (5) to form its mega- Spores Similarly to Eichhornia. Commonly no cell walls are formed Detween the four spore nuclei, but the lower of these nuclei develops into the embryo sac and the other three degenerate. A case resembling that of Avena and Eichhornia is reported as 208 BOTANICAL GAZETTE [SEPTEMBER occurring in Crucianella by Lroyp (15). He reports that in three species of Crucianella investigated, four megaspores were formed which were not separated by cell walls, and that “only occasional exceptions could be found to this.” The upper of these four nuclei develops into the embryo sac, and the three lower finally degenerate. Not uncommonly these three lower nuclei undergo division. Many cases were seen, Lioyp reports, in which the four megaspores had each divided once, thus forming eight nuclei in a common cavity. He says: “If these divisions are regarded as the first mitoses of an embryo sac we have four embryo sacs lying tandem.” Only the one lying adjacent to the micropyle attains full development. Al- though he reports the disintegration of the lower megaspores, his figures admit other interpretations. As late as the third division of the functional megaspore, what he interprets to be one of the three lower megaspore nuclei is shown dividing in the same cavity with the four dividing nuclei of the embryo sac. The dividing nuclei seem to have the same appearance in every way. This would cer- tainly show a prolonged activity on the part of these three inner megaspores. This delayed germination of the lower megaspores and the similarity of the dividing nuclei in every way, open up many possibilities. The exact fate of the eight free nuclei formed by the division of all four of the megaspores is left unsettled. LLoyD com cludes that the outer megaspore attains full development, and that the eight nuclei therefore never organize to form an embryo sac jointly. This is a most interesting case, and a complete history of the embryo sac from the mother cell may throw light on the interpretation of multinucleate embryo sacs. This omission of the division walls between the megaspores of a tetrad is found by Luovp also in Asperula, which is related to Cru- cianella. Any one of four spores may germinate to form the a sac, and the/other three finally degenerate. The three spores wit do not germinate are at times difficult to distinguish from antipod nuclei. An important conclusion to be derived from the behavior : of Fichhornia, Avena, Crucianella, and Asperula is that the - walls are not essential to the individualization of a spore, and tha ; the failure to form division walls between the megaspores does N° > SESE EET SD ea eae el Me a oo ge — eee | te’ >= or: pee ; 3 " 3 : : 1909] MCALLISTER—EMBRYO SAC OF SMILACINA 209 necessarily result in the lily type of embryo sac, even though the nuclei seem to be of the same size and vitality. So long as the spore retains its individuality as such, we can expect each spore to develop into a separate gametophyte, and not till this individuality is lost can we expect to find more than one spore entering into the structure of a single gametophyte. This absence of division walls, however, may very well lead directly to such joint organization of a gametophyte as we find in Smilacina. Luoyp, in discussing the nature of the first four nuclei of the embryo sac of the lily, is in favor of calling them spores. “But after all,” he says, “spores in the sense meant here are equivalent to vegetative cells of a somewhat special sort, with no necessarily separate existence teleologically speaking.” He urges against the idea that in the lilies the gametophyte begins with the mother cell this: “It would seem more natural to regard the gametophyte as an individual by coalescence, having its origin in four like vegetative cells whose primitive function has been lost.” In Pandanus Artocarpus and P. odoratissimus, according to CAMPBELL (4), the mother cell develops directly into the 14-nucleate embryo sac. The two outer nuclei formed by the reduction divisions do not divide, while the two inner nuclei divide to form twelve nuclei. A differentiation of the antipodal cells was reported, but no certain evidence of nuclear fusions to form the endosperm nucleus was found. In 1907 Porscu (20) proposed the theory that the two cell groups in the opposite ends of the angiosperm embryo sac are both to be in- terpreted as archegonia. The synergids are thought to correspond to two neck canal cells, and the upper polar nucleus to the ventral canal cell of the archegonium. According to this theory the embryo sac of Helosis consists of only one archegonium, the other having been Suppressed. The behavior of Smilacina stellata perhaps supports is theory, in so far as it shows the equivalent origin of the two groups of nuclei which Porscu interprets as archegonia. Miss Pace. (19) has reported that Cypripedium forms a iota celled embryo sac by two divisions of the lower of two “megaspores- This embryo sac may be interpreted by Porscu’s theory to bea single archegonium. é | Went (28), in a recent article on the Podostemaceae, reports that 210 BOTANICAL GAZETTE [SEPTEMBER in Oenone and Mourera a four-celled embryo sac is formed, similar to that in Helosis. The mother cell following synapsis divides to form two daughter cells, the upper degenerating. The lower daughter cell (which he calls the “megaspore’’) divides, and the innermost nucleus shrinks immediately to a shapeless mass of chromatin that is visible for a long time. This inner nucleus, though one of the first four nuclei formed by the division of the embryo sac mother cell, is interpreted by WENT as a nucleus of the embryo sac and not a spore. The nucleus remaining from the second division divides twice to form the four-celled embryo sac. The lower nucleus of this embryo sac degenerates, leaving only the three nuclei which form the egg apparatus. WENT notes that his results support the theory of Porscu, except that the ventral canal cell is on the wrong side of the cog. ERNST (10) has expressed the opinion that the 16-nucleate embryo sac of Gunnera, as described by him, consists of two of the archegonia of PorscH in the chalazal end of the embryo sac and one in the micropylar end. Four nuclei in the central region of the embryo sac fail to form an archegonium, and unite with a polar nucleus from each archegonium to form the endosperm nucleus. STEPHENS (23), in a preliminary note on certain Penaeactaé, reports that the sixteen nuclei of the embryo sac become divided into four groups, which lie at some distance from one another against the wall of the embryo sac. Three nuclei out of each group of four organize what appears to be an egg apparatus, while one nucleus from each group acts as a polar nucleus, and the four unite to form the endosperm nucleus. On Porscu’s theory these four groups would represent four archegonia. These examples seem to indicate a tendency of the nuclei of the angiosperm embryo sac to form groups of four. The evidence in favor of the archegoniate character of these groups, however, seceia to me to be insufficient as yet. The relationship between the angio” sperms and the gymnosperms is so remote that a comparison of the embryo sacs of the two groups with a view to homologizing sts groups of nuclei associated with the egg is very difficult. ae CouLTer (8) further defends the idea that the first four nucle 0" the embryo sac of the lily are megaspores, or “at least their nuclel- Ig09] MCALLISTER—EMBRYO SAC OF SMILACINA 211 His evidence lies in the fact of their being the product of the two reduc- tion divisions. Hence they must be “megaspore nuclei, to be recog- nized as such by their cytological history and structure.” The 16- nucleate embryo sacs of Peperomia pellucida are considered as result- ing from two divisions of each of these megaspore nuclei, and the 8- and 16-nucleate embryo sacs, which JOHNSON reports as occurring in Peperomia hispidula, are regarded as formed by one division of each of the. four megaspore nuclei to form the 8-nucleate embryo sac, and by two divisions of each to form the ‘16-nucleate embryo sac. CouLTER is inclined to regard it as a fundamental law that the angiosperm embryo sac is formed from the mother cell by never more than five nuclear divisions, the reduction divisions and three divisions of a megaspore. He concludes that the large number of nuclei in the embryo sacs of Peperomia and Pandanus may originate by the participation of more than one spore in their organization. This implies, further, that any embryo sac formed from one spore which has sixteen or more nuclei can be considered as relatively primitive, since it would require more than five nuclear divisions to produce it from the mother cell. I do not see why the cases of the proliferation of antipodal nuclei should not be given more weight in the evidence. There is certainly an abundance of cases among the grasses and in the Ranunculaceae, as well as in other families, in which the innermost nuclei of the embryo sac are the product of more than five divisions previous to fertilization. It seems doubtful whether the embryo sac with more than eight nuclei can be explained on any such simple hypothesis, and it is to be remembered that, while there is apparently a physio- logical necessity back of the double division, there is nothing, ce STRASBURGER has noted, in the phylogeny of the angiosperms which would explain or give special significance to a fivefold division. Brown (1) reports that evanescent cell walls are formed separat- ing the first four nuclei of the embryo sac of Peperomia Sintensn and P. arijolia, in both of which the mother cell develops directly into the embryo sac. Though evidently convinced that in Peperemaes these first four nuclei are megaspores, BROWN seems to object to the adoption of this explanation for the lily type of embryo sac in general. 212 j BOTANICAL GAZETTE [SEPTEMBER Referring to the number of divisions which archesporial cells undergo to form the mother cell, he says: “Since we can trace the reduction of these divisions until, among the angiosperms, the archesporial cell may, without dividing, form one megaspore mother cell, it does not seem reasonable to suppose that the divisions of the mother cell to form four megaspores may not also be left out, and the mother cell function directly as a megaspore.” Any analogy, however, based upon the archesporial cell, has against it that this latter cell is a doubtful morphological unit. It cannot be maintained that any morphological interpretation yet proposed satisfactorily explains all the diverse types of embryo sac formation which have been described. That there are so many variations in important particulars gives ground for the expectation that further study may fill up many gaps in our current interpretations. It is plain that within the group of the Convallariaceae there ” types which go far toward explaining the origin of the old and familiar lily type of embryo sac. It is certainly plain that in Smilacina stellata four megaspores are formed, which are unmistakably separated by cell walls and subsequently recombine to form the first four nuclei of the embryo sac. All the evidence favors the view that the first four nuclei of the lily embryo sac are morphologically, as well as from the standpoint of the reduction divisions, to be interpreted as megaspore nuclei. SUMMARY 1. The mother cell of Smilacina stellata divides twice to form fout nuclei, which are separated by walls to form four megaspores. 2. The division walls and plasma membranes which separate me four nuclei are absorbed, so that the four reduction nuclei ocCUPY a common cell cavity. : 3- Each of these four nuclei divides again, and the resulting eight nuclei organize to form the embryo sac. 4. It is plain from these facts that we have four individual meg* spore cells*combining to form one embryo sac or gametophyte ™ Smilacina stellata. 6 5. It is thus strongly suggested that in the embryo sac of the hie the first four nuclei are morphologically megaspores. Ree? Sey ea eee Ree era ee hh eS, 1909] MCALLISTER—EMBRYO SAC OF SMILACINA 213 6. In Smilacina racemosa the outer daughter cell of the hetero- typic division develops into the embryo sac, although the long per- sistence of the two nuclei formed by the division of the inner hetero- typic nucleus might suggest that they should be considered a part of the embryo sac. Smilacina racemosa shows temporary cell division at the close of the homeotypic division, agreeing in this respect with Smilacina stellata. I wish to express my obligations to Professor H. D. DENSMoRE, in whose laboratory at Beloit College this investigation has been largely carried on. I am also indebted to Professor R. A. HarPEr for his sug- gestions and criticisms during the preparation of the manuscript. LITERATURE CITED I. Brown, W. H., The nature of the embryo sac of Peperomia. Bot. GAZETTE 46: 445-460. pls. 31-33. 1908. 2. Campsett, D. H., A peculiar embryo sac in Peperomia pellucida. Annals of Botany 13:626. 1899. 3: ———, Die Entwicklung des Embryosackes von Peperomia pellucida Knuth. Ber. Deutsch. Bot. Gesells. 1'7: 452-456. pl. 31. 1899. ‘ —— The embryo sac of Pandanus. Annals of Botany 22:330. 1908. » Cannon, W. A., A morphological study of the flower and embryo of the wild Oat, Avena fatua. Proc. Calif. Acad. Sci. III. 1:329-364. pls. 49-53. 1900. 6. CHAMBERLAIN, C. J., Winter characteristics of certain sporangia. Bor. GAZETTE 25:124-128. pl. rr. 1898. Cxopar, R., eT BERNARD, C., Sur le sac embryonnaire de l’Helosis guaya- nensis, ap oA PEENE ol Oo ty g Re] > Q of °o 8 g 3 3 o Qu E = ( 8 5 Z am FE & ty 5 a g g S a Befruchtung bei Paris quadrifolia und Trillium grandiflorum. Flora 91:1- 46. pls. 1-6. 1902. = aa, Zur Phylogenie des Embryosackes der Angiospermen. Ber. Deutsch ot. Gesells. 26a: 419-437. pl. 7. 1908. ™ Guicnazn, L., Stracture et division du noyau cellulaire. Ann. Sci. Nat. ~~» Nouvelles études sur la fécondation. Ann. Sci. Nat. Bot. VII. 14: 163-296. pls. 9-18. 1891. : A » Jonson, D. S., On the endosperm and embryo of Peperomia pellucida. OT. GazETTE 30: 1-11. pl. 1. 1900. 214 BOTANICAL GAZETTE [SEPTEMBER 14. JoHNson, D. S., A new type of embryo sac in Peperomia. Johns Hopkins Univ. Circ. 195: 19-21. pls. 5, 6. 1907. 15. Luoyp, F. E., The comparative embryology of the Rubiaceae. Mem. Torr. Bot. Club 8:1-112. pls. 8-15. 1902. 16. Overton, E., Beitrag zur Kenntniss der ooucctn: und Vereinigung der Geschlechiaproducts bei Lilium Martagon. Zurich. 1891. , Ueber die Reduktion der Chromosomen in den Kernen der Pflanzen. Vierteljahresch: Naturf. Gesells. Zurich 38: 169-186. 1893. , On the reduction of the chromosomes in the nuclei of plants. Annals of Botany '7:139-143. 1893. 19. Pace, Luta, Fertilization in Cypripedium. Bor. GAZETTE 44:353-374 pls. 24-27. 1908. 20. PorscH, O., Versuch einer phylogenetischen Erklirung des Embryosackes und der Sor eslien ee der Angiospermen. 1907- 21. ScHNIEWIND-TuIES, J., Die Reduktion der Chromosomenzahl und die ihr folgenden Ketathehaiigen i in den Embryosackmutterzellen der Angiospermen. Jena. 1901. 22. SuirH, R. W., A contribution to the life history of the Pontederiaceae. BOT GAZETTE 25: 324-337. pls. 19, 20. 1898. 23. SrepHEns, E. L., A preliminary note on the embryo sac of certain Penaeaceae- Annals of Romany 22:329. 1908. 24. STRASBURGER, E., Neue Untersuchungen iiber den Befruchtungsvorgang © bei den Phavistoeames. Jena. 1884. , Ueber Kern- und Zelltheilung im Pflanzenreich. Hist. Beitr. T. Jena. 1888 , The periodic reduction of the number of chromosomes in the life heise of living organisms. Annals of Botany 8:281-316. 1894- : =e brat: Ms es igus. J. F. A., Notice sur le développement du s4 Archives Neerlandaises 15:45?” 4 o = 456. pls. 2. 1880. + th . Went, F. A. F. C., The development of the ovule, embryo sac, and egg in the ; Podostemaceae. Recueil Trav. Bot. Néerl. 5:1-16. pl. I. I ‘ 29. WiEGAND, K. M., The development of the embryo sac in some » monocot ledonous plants. ‘Ber: GAZETTE 30:25-47. pls. 6, 7. 1900. EXPLANATION OF PLATE XV All figures were drawn with the aid of a camera lucida. The magnification in all the drawings is 670 diameters. The micropylar end is upward _ drawing. Fic. 1.—Mother cell in synapsis stage; without tapetal cell. Fic. 2.—Mother cell in prophase stage of first division; two cell layers the epidermis and the mother cell. : ple Fic. 3.—Early metaphase stage of the mother cell, showing thick dow chromosomes characteristic of first reduction division “pea oO betwee PLATE XV McALLISTER on SMILACINA BOTANICAL GAZETTE, XLVIII Igog] MCALLISTER—EMBRYO SAC OF SMILACINA 215 Fic. 4.—Formation of cell plate and daughter nuclei at the close of first _ division of mother ce 2 . ; i cal et FS Fic. 5.—Early metaphase stage of homotypic division; axes of spindles oblique. Fic. 6.—Daughter nuclei and cell plates f outer daughter cell dividing transversely and inner one longitudinally. Fic. 7.—Nuclei of second division fully formed, arranged bilaterally; division membranes of second division do not reach outside walls. Fic. 8.—The outer daughter cell has divided longitudinally and the inner one transversely. FIGs. 9, 10.—Two successive sections of the same nucellus, showing the division of an approximately spherical mother cell; hete rotypic division longitudinal; one daughter cell in the homeotypic division dividing longitudinally and the other transversely. Fic. 11.—Row of four very large megaspores, with the division =e very inde- ite. Fic. 12.—Commonest arrangement of megaspores, in which first division is oblique and second at right angles to first; walls have disappeared but plasma membranes still persist. ae IG. 13.—Four megaspores; a cleft between two middle nuclei is all that remains of division membranes of cells. é Fic. 14.—Four megaspores, with no traces of cell walls, forming four-celled Stage of embryo sac. Fics. 15, 16.—Stages in the vacuolation of the four-celled embryo sac. Fic. 17.—Eight-celled embryo sac, showing micropylar and antipodal groups of nuclei, the two polar nuclei already separated out. ] £ d divician: ’ A STUDY OF PINON PINE P.n}6 PHLIELIPS GENERAL DISTRIBUTION No other tree species of the southern portion of the Rocky Moun- tain region presents more difficult problems in maintaining and repro- ducing the natural stands than does the pifion pine (Pinus edulis). It ranges from northern Mexico to eastern Utah, and Colorado Springs, Colorado. In an east-and-west direction it extends from the hills of western Texas to California. Along the northern and eastern borders of its range it is shrublike and of botanical importance only. In southern Colorado, Arizona, and New Mexico, it has a great eco- nomic and silvicultural importance, which will steadily decrease unless measures are taken to prevent excessive utilization. It is commonly found in mixture with the one-seeded juniper (Juniperus monosperma) in the northern part of its range and with the alligator juniper (Juniperus pachyphloea) and one-seeded juniper in the south. Throughout its distribution it is associated with weste™™ yellow pine (Pinus ponderosa) and the scrub oaks (Quercus Gambelit and Quercus acuminata), often forming with these species a transition belt between stands of juniper and western yellow pine. Occasionally it is found with stunted Douglas fir (Pseudotsuga taxifolia). In association with the junipers, it forms the distinct woodland type so characteristic of New Mexico and Arizona, which in this reg! covers a more extensive area than any other forest type, and 63 which the pifion is decidedly the most important tree. It is occasion- ally seen in pure stands over small areas, but this is rare. LOCAL OCCURRENCE The tree thrives best at a general elevation of 1650 to 2350" (540° to 7700 feet) on moderate to steep mountain slopes and over road, level, or sloping mesas. Small isolated specimens were found UP to an elevation of 2600 and 2750™ (8500 and gooo feet), while occ Botanical Gazette, vol. 48] [2x6 pie ME a Milk ee Eos, Game - 1909] PHILLIPS--A STUDY OF PINON PINE 217 sional specimens may be found even higher than this. The best stands are found on coarse gravel, gravelly loam, or a coarse sand, of 1.5™ (5 feet) or more in depth, on which humus and ground cover are almost entirely lacking. The species often occurs on rocky areas, where the soil is only 15 to 30°™ (6-12) in depth, and fre- quently it is found growing in rock crevices. It is one of the first trees to gain a foothold on the lava overflows which are known throughout the southwest as mal pais. This rock in its disintegrated form supports fair tree growth, but even before disintegration has progressed very far, the junipers and pifion may be found encroaching upon it. Another encroachment form of the pifion is to be found on small mounds which rise 0.6 to 3™ (2 to 10 feet) above the general level of the desert-like tableland at approximately 1500™ (5000 feet) elevation. On such islands as these, the pifion and one-seeded juniper take possession and maintain a limited growth. The same feature is noted at the bases of the hill and mountain slopes which bound these tablelands. This remarkably distinct tension line seems to be due to a greater soil porosity, less grass growth, and a smaller alkali content, which are manifest in slightly higher elevations. The distribution of these trees on such small mounds and limited in such a distinctive manner presents an ecological problem for future investi- gation. On slopes where site conditions are favorable for western yellow pine, the pifion usually occupies the south and west aspects. Where Conditions become less favorable, it occupies the north and east slopes, while the south and west slopes are bare or nearly so. This ability to stand poor conditions is also shown on a large number of mountain Slopes ranging from 2830 to 3135™ (6000 to 7000 feet) in elevation, where scattering Douglas fir, of scrubby growth and badly affected With witch’s broom, is found in the cafions; western yellow pine on the middle slopes; and pifion on the ridges and upper slopes, where the soil is scant and the soil moisture low. A distinctive peculiarity was observed between Servilleta and Taos, New Mexico, in an open stand of the species in which approximately two-thirds of the trees have constricted bases at the surface of the stound. This constriction amounted to an average of 197" (0.75") 218 BOTANICAL GAZETTE [SEPTEMBER in radius, but was occasionally noted where it amounted to 38™™ (r.5™). Such a constriction is often seen on individual trees in nearly any stand, but in no other case was it found to be a stand as characteristic as it was near Servilleta. Pifion is also resistant to severe climatic conditions, since it will succeed over severely exposed slopes where the average annual precipitation is less than 33°™ (13%) and where evaporation and transpiration are high because of the semi-arid climate, the large amount of sunshine, and the prevalence of winds. In this respect it is undoubtedly the most resistant pine in the southwest. However, it prefers a slightly greater precipitation and areas less exposed to the wind. An example of the unfavorable influence of strong winds and a Close-textured soil was noted in the vicinity of Fort Stanton, New Mexico, where a level plateau of nearly 8" (5 miles) in length did not support a single tree, while similar plateaus on all sides, with less wind sweep and a coarser soil, showed luxuriant growth of both the pifion and the juniper. The tree does not live as long as the junipers, and in general is less resistant to unfavorable climatic conditions. In the drought which occurred in New Mexico from 188g to 1904; pifion suffered considerably more than the junipers. Many mixed stands were observed in New Mexico and southern Colorado in which 75 to 95 per cent. of all dead trees were pifion. In the frost which occurred in April, 1907, pifion was affected, while the junipers resisted practically all injury. In the wet freezing snow of October, 1906, which caused immense damage to the forests of the southwest, fewer branches were broken from the pifion than from the brittle junipers. The tree is also more resistant to disease than most of the conifers with which it associates. It is much less affected by the so-called false mistletoe (Razoumofskya) than is the western yellow pine and the junipers. It has fewer insect enemies than the western yellow pine, and is not affected by the witch’s broom as is often the case with Douglas fir in the southwest. TOLERANCE AND FORM Pifon is distinctly an intolerant tree. During its seedling — it prefers a moderate shade, and hence reproduces best under thé 1909] _ PHILLIPS—A STUDY OF PINON PINE 219 shade of older trees. After the seedling stage is passed it prefers the open, and is one of the most intolerant of forest trees. This gives an orchard-like appearance to most stands of this species. Occasionally stands of 0.7 density were noted, although few stands have more than 0.6 density. On the best sites the trees reach a maximum height of 12 to 13.7™ (40 to 45 feet) and a diameter of 60 to 75°™ (2 to 2.5 feet) at breast height, but ordinarily the mature individuals range from 3 to 10.5™ (10 to 35 feet) in height and from 15 to 45°™ (0.5 to 1.5 feet) in diam- eter. A difference in development was apparent on different sites. On exposed sites the tree is globular, very scraggly when mature, and has little or no clear length. On favorable sites trees in the open have a very short clear length and a fairly regular globular or egg- shaped crown. If grown in stands, the trees have a greater clear length and a flat or vase-shaped crown. Young trees on favorable sites are conical or globular in shape and usually very regular in form. On the most exposed sites, shrublike trees were found which were fifty to eighty years old, and only 1.8 to 3™ (6 to 10 feet) in height, with a crown diameter reaching a maximum of two to four times the height of the tree. On such trees it was impossible to dis- tinguish the leader from the branches, and the general appearance of the tree was much like that of the dwarf mountain pine (Pinus monticola). The foliage is more densely clustered on these dwarf trees than it is on trees in the open, with shorter and apparently thicker leaves. Practically all trees, whether growing on poor or 800d sites, are characterized by dead and half-dead branches, which are retained on the tree for several years. This is characteristic of nearly all species in the southwest and is due to the small amount of Stowth that is made, the necessity of retaining only a small amount of living tissue, and the dry nature of the climate, which allows the retention of dead branches for a longer period than would a moist Climate. In exceptional stands, such as occur to the west of Servil- leta, New Mexico, where a clear length of 4.5 to7.6™ (15 to 25 feet) 'S not exceptional, the branches are shed largely because the density of stand prevents the formation of as large branches as are found in those trees which enjoy full sunlight. 220 BOTANICAL GAZETTE [SEPTEMBER WwooD Pifion wood is moderately heavy for the pines. It is used exten- sively for fuel and has been limitedly used for fence posts, telephone poles, corral posts, mine lagging, railroad ties, charcoal, and inferior lumber. Some authorities have recommended its use for fence posts, but this is to be seriously questioned as it has little durability in contact with the soil, and even the natives are discarding it for such use. It may be rendered valuable, however, by the use of preservatives. The tree is remarkable in its fuel value, and its use for such a purpose should be greatly encouraged. It is a common practice to cut branches or trees after they have been dead about two years. If cut before this time, the wood has not seasoned sufficiently to burn readily. If cut after this time, it has usually deteriorated to some extent. As a hearth fuel, it is not surpassed by another conifer and by only few hardwoods. It starts to burn readily, retains fire for a con- siderable length of time, gives a large amount of heat, and does not throw sparks. Since open fires are very common in this region, this wood serves an excellent purpose. Sample acres which have been clear cut have given a yield of 180 to 360%™ per hectare (20 to 4° cords per acre), while extensive stands have averaged go to 108% ™ (10 to 12 cords). FRUIT The young cones are dark red and occur in elongated clusters. The pistillate form is easily distinguished by short stalks. Both sorts are very plentiful in seed years, but are scarce during other years. The mature cone is short, top-shaped, 19 to 50"™ (0.75 2") long and often as broad as long. The cones open on the tree and are covered by a large amount of free resin, which makes aes difficult to handle. They often occur on trees only 0.9 to 3° (3 to 4 feet) in height, which are ten to twenty years old, but the best crops are borne on mature trees which produce 35 to 280 (1 bushels) of cones; each cone contains two to thirty seeds, with _ average of ten to twenty seeds. The trees have been known to yiel 336 of seed per hectare (300 pounds per acre), while a much large area has been known to produce an average of 7 3k# per hectare (65 pounds per acre). hg) ee eee i eee si, ie Erle 1 1909] PHILLIPS—A STUDY OF PINON PINE _ 221 Seed years usually occur at five-year intervals, but have been reported at shorter intervals than this. The seed is well rounded at the base, tapering with prominent ridges to an acute point. It is usually dark brown on the lower side, with more or less mottled orange yellow on the upper side, 9 to 12.5™™ (0.375 to 0.5") long, 6.5 tog™™ (0.25 to 0.375!) broad, with a thin shell which cracks most easily along the line of the most prominent ridge. The seed wings are about one-half the length of the seed, easily detached, and of no practical use in seed distribution. The seeds usually have a high percentage of infertility, which varies from 5 to 20 per cent., but in one case went as high as 85 per cent. Poor seeds are often lighter in color than good seeds. Germination power is lost very readily, which necessitates special storing when they are to be used for artificial planting, and good site-conditions when the stands are to be reproduced naturally. It is a matter of note that the seeds from the northern portion of the range are usually considered better than those from the south. Five —— collected in various localities gave the following results: pound, | Poy | Peseause | Pereatege | Perce | where cllecd (453.68™) | knife test | water test | greenhouse in open 3510 N. M. oheied 87.2 84.0 82.2 5.6 Ft. Bayard, 2215 89 I 86.6 80.3 is 2 Tres Piedras, N. M one QI.2 86.0 78.1 70.4 | Ft. Garland, Col. 1950 92.7 88.5 81.3 71.0 | Ft. Garland, Col ss 99.2 97-1 96.4 90.3 Lincoln, N Weevils sometimes affect the seed before the cones open. Birds and rodents eat the seed extensively, and stores are made ses moun- tain rats which were found to contain a maximum of 35 to 70! (I to 2 bushels) of clean seed. Ants are known to eat seed, especially at lower levels. In the early days, the Indians and Mexicans used the Pifion as a staple article of food. At present, it is gathered in immense quantities and sold as a delicacy. It is eaten most extensively in and about the region where the tree grows naturally, but large amounts are being sold at fruit stands throughout most of the United States. To prevent the seeds from spoiling and to retain flavor, they are "sually baked immediately after being gathered. 222 BOTANICAL GAZETTE [SEPTEMBER Most of the seeds are collected by Mexican women and children, who usually spread a sheet or blanket on the ground and then shake or pound the tree and its branches until the seeds fall from the open cone. Later in the season, the seeds are picked up by hand from the ground beneath the trees. In the best part of the seed harvest, enough are gathered by single families to be sold by the grain bag full or the wagon load. Since the Mexicans take almost no precau- tions against the spreading of smallpox, it is said that the worst ravages of the disease occur during a seed year of the pifion. Single dealers have- been reported as having bought gooo to 21,5008 (20,000 to 50,000 pounds). The delicate flavor of the seed makes it a favorite, and an extensive market is being rapidly developed for it. During seed years the native collectors sell it at the rate of five to fifteen cents per pound, according to the ease of collecting the seed and the prox- imity of the market, while dealers in many of our cities sell the seed at a rate of forty to sixty cents per pound. REPRODUCTION Natural reproduction is limited because of the infrequency of seed years, unfavorable climatic conditions, infertility of seed, rapidity with which the seed loses its germination power, loss of seed eaten by rodents, birds, and man, and unfavorable site-conditions. Grazing interests are also a factor in limiting the reproduction of the species since sheep, cattle, and goats are grazed throughout its entire distri- bution. It is apparent to even the casual observer that extremely large areas are not reproducing themselves, yet owing to the difficulties of site and the methods by which the tree may be reproduced, the prob- lem of reproduction is an extremely difficult one, and one for which, at the present time, no adequate solution can be offered. FUTURE MANAGEMENT From the nature of the stand in the southwest, it is apparent that clear cutting would not be ari advisable system, because of the exposure of the site and the difficulties of restoring the stand. On the other hand, the large amount of seed consumed by man and other agencies makes natural seeding exceedingly difficult, and even though gt?! and fire are entirely eliminated, it is doubtful if satisfactory reproduc: ryo9] PHILLIPS—A STUDY OF PINON PINE 223 tion will be secured in even a bare majority of sites. Until the prob- lem of reproduction is more thoroughly worked out, the policy should be to remove only the dead and dying pifion trees for fuel, thus allow- ing a careful management without encroaching seriously upon the natural stands as is being done at the present time. It would seem from the nature of the site that the stand could be made to succeed best by the selection system, consisting of the removal of the dying trees. The sale of this fuel with that of a large portion of the seed should furnish a moderate income. This production would be low, as contrasted with high-type coniferous forests in other regions, but when consideration is given to the value of this species for fuel and seed, the question of immediate returns is a minor one. UNIVERSITY OF NEBRASKA BRIEFER ARTICLES ON THE DEMONSTRATION OF THE FORMATION OF STARCH IN LEAVES For a qualitative demonstration of photosynthesis in starch-forming © leaves it is advantageous to know the time in darkness required for the disappearance of accumulated starch, and the time in light required for its subsequent demonstrable formation. No general rule can be given for either, since the time required varies widely for the different species. Therefore, in continuation of the series of studies carried on in the labora- tory of plant physiology of Smith College on the physiological constants of the educationally useful plants,t I have tried to determine these data for such plants, and also, by comparison, the best plants for the purpost- Throughout this paper I have used the expression “disappearance of starch” rather than ‘“‘translocation.” In a general way the processes, of course, correspond, yet the term “translocation” implies the removal 0: the starch from the leaf, while here we are dealing only with its disappe*™ ance as starch. : The method employed in the present study was as follows: Five actively growing plants of each species, always after a bright day and between 4 2 5 o’clock, were put in a dark room having a steady temperature of 18°-22° C. as recorded by a thermograph. Twice a day, about 9 A. M. and 2 P. M., leaves were tested for starch by SAcHs’s iodine method, and the time when all starch had disappeared was noted. No attempt was made to find the exact hour when the leaves were empty. This would necessitate testing them every hour during the night as well as during the day, purpose of the present study, the results would be of little value- following table, therefore, the time in darkness required to empty the of starch is given in night and day periods rather than in hours. iodin test the leaves were first boiled 1 minute to swell the starch, blanched in warm alcohol, were put in water a few minutes to remove of alcohol and soften the tissues, and were then immersed in 4 solution 0 iodin. The solution used was git potassium iodid, 1°™ iodin, 10% watel, to which, when dissolved, water was added to make 1 liter of solution. fie Thus was the time of disappearance of starch determined with su cient accuracy for all practical purposes. To determine the time Ted" ‘Bor. GAazETTE 40:302. 1905; 45350. 1908; 482254. 1908; 465° 1968 46:221. 1908. Botanical Gazette, vol. 48] leaves or the were the [224 PO Le eT 1909] BRIEFER ARTICLES 225 for starch formation, it was found best to use some type of screen such that a sharp contrast would show between the light and dark parts; and for this purpose light-screen boxes were used. .These boxes have been fully described by Professor GANONG in the Botanical GAZzETTE.? Briefly, they are small boxes made of white paper blackened inside, with a network of threads across the top to support the leaf, and holes near the bottom to allow the air to pass through freely. A glass plate covered with tinfoil having a pattern cut in it is held closely against the network by a wire spring. When in use the leaf is held between the glass plate and the net- work. The principal advantage of these screens is that while excluding all light, they allow nearly the normal access of carbon dioxid to the leaf. The caution, by the way, against using screens which cut off all carbon dioxid as well as the light has been made several times in recent years, but some of the new elementary textbooks are still copying the old and erroneous method of putting cork or tinfoil on both sides of the leaf. Several light- screen boxes were attached to the leaves which had previously been emptied of starch, and the plants were placed in strong diffuse light. Leaves were then taken off and tested for starch at 10-minute intervals. In order to compensate the effects of individual peculiarities, 5 plants of each species were tested. The results given in the table are for full-grown (except in : € three cases noted), but not mature, leaves on actively growing plants, M pots, in a greenhouse. In the first column is given the time in darkness Tequired to empty the leaves of starch; in the second, the time in diffuse light required to. make enough starch to show a pale but clearly defined figure with the iodin test; in the third, the time required to show a sharply defined, dark figure; while in the fourth is given the time required for the lodin to produce its full effect. The best leaves, obviously, for this study are those in which photosynthe- Sis is most active, from which starch disappears most rapidly in darkness, from which the chlorophyll can be extracted quickly leaving the leaf white, and which give the iodin reaction quickly. As shown by the accompanying table, these are Pelargonium hortorum zonale, Fuchsia speciosa, Senecio mikanioides, Impatiens Sultani, and young plants of Helianthus annuus, Ricinus communis, Phaseolus vulgaris, Zea Mais, and Cucurbita Pepo. On the other hand, some leaves are not good for this study. Begonia palmata, Oxalis Bowiei, and Pelargonium peltatum, when boiled to swell the Starch, partially disintegrate, so that the figure does not show clearly with the iodin test. It is possible, of course, to apply the iodin test without Previous boiling of the leaf, but it takes 24 to 48 hours according to the * Bor. Gazerre 432277. 1907. 226 BOTANICAL GAZETTE [SEPTEMBER age of the leaf; besides, these leaves turn brownish yellow on the applica- tion of iodin and therefore do not show clearly the reaction with starch. Ficus elastica requires more than one day to make a perceptible amount. Only very young leaves of Primula obconica, Primula sinensis, and Cinera- ria cruenta can be emptied of starch; being stemless plants, they probably use the older leaves for its storage. Young plants of Pelargonium domesti- Disavprap- segs ea Sad fee NAME OF PLANT Retintag lt (T. 20°-25°C.) IopIN TEST : DARKNESS (T. 18°-22° C.) Perceptible fig. Good fig. | nights and days minutes minutes minutes PINNUOasiiat oe er oo ce 2 I 30 120 es Begonia coccinea........... 3 3 60 240 B ca oleracea...) ... 2s. ° 20 5 5 Cineraria cruenta (young Is)| 5 4 45 180 3° Coleus Blumei............. I 30 5° 36 Cucurbita Pepo............ I ° 15 5° as Euphorbia pulcherrima 2 I 60 240 Fuchsia speciosa........... I ° 45 9 15°95 Helianthus annuus......... I ° 30 120 Heliotropium peruvianum I ° 45 120 s Bie Impatiens Sultani.......... I ° 30 120 Lupinus albus............. I ° 60 240 alis Bowiei............. I ° 45 240 petits Pelargonium domesticum...| 2 I 5° 240 4 Pelargonium peltatum...... = 2 50 270 = Pelargoni rto x : OMS 2 I 20 5° ~_ Phaseolus vulgaris......... I ° 20 oe 5 ° Primula obconica (young Is). 5 4 120 240 s* Primula sinensis (young ls) . 4 fe 45 120 Raphan se ea fe) 35 6 3 Ricinus communis... .... I ° 20 60 oss Salvia involucrata.......... 2 I go I20 ait Salvia splendens........... 3 2 30 60 =e Senecio mikanioides....... . I ° 20 5° 5 Senecio Petasitis........... 3 2 30 180 25 Tropaeol 1 Rear tis 2 I 50 ge ; Wels Pathe cates: I ° 60 240 = Cl TMI ss 3 2 30 120 5 cum empty their leaves of starch in about 40 hours, but older p _ - unsatisfactory, because, even after 4 days in darkness, there are ant d of starch in the mesophyll. All these plants, except Oxalis Bowtet, er the young plants of Pelargonium domesticum, require 3 to 5 days in darkm —too long a time for the subsequent good of the plant. First Prolonged darkness produces two distinct deleterious results. : some plants, as Heliotropium and Impatiens, after 3 or 4 days in ose drop their leaves, owing to some derangement of their mechanis™, Ig09] BRIEFER ARTICLES 227 cause of which I have not investigated. Also, Tropaeolum leaves soon turn yellow in darkness. The second injurious result, and the most impor- tant in this study, occurs in nearly all plants. Some of the photosynthate is of course being constantly used in growth or for storage in the stem, and since the plant can make no more in darkness, the percentage of sugar in the cell-sap decreases more and more by diffusion into the stem. Then, as PFEFFER has shown,3 when the plant is brought into the light no starch is deposited until this percentage of sugar is repaired. The following example is typical: Two plants of Fuchsia speciosa, apparently alike, were put in the light at the same time, after having been in darkness, the one 64 hours, the other 16 hours. Halves of leaves tested showed no starch. After 2 hours in the light, the other halves on the first plant showed much less starch than those on the second plant. To obtain the most rapid formation of starch, therefore, it is important that the plant should be kept in darkness only long enough just to cause the disappearance of starch. The disappearance of starch is not always even. In Coleus, Primula verticillata, Primula obconica, and Fuchsia speciosa, the base of the leaf is emptied of starch before the tip. This agrees with what SacHs found in Some other leaves.4 So far as I have tested them, I have found this to be true only of ovate or oblong leaves. This may be correlated with the greater abundance of stomata near the base of the leaf. _In round leaves like Pelar- gonium zonale and Tropaeolum, the starch seems to disappear evenly from all parts. The starch disappears from the young leaves on a plant before It does from those which are mature. The effects of temperature on the amount of starch present are especially important. In several of my experiments, leaves of Fuchsia spectosa, Euphorbia pulcherrima, and Pelargonium zonale which were kept in direct sunlight 4 hours showed very little starch, while leaves on plants in diffuse light, at the end of 4 hours were full of starch. Fuchsia speciosa after being in diffuse light at 28°-31° C. for 3 hours showed only a trace of starch, while other leaves in 3 hours at 18°-20° C. appeared black with starch, with the lodin test. A comparison of these two sets of experiments shows that the small amount of starch present in leaves in direct sunlight isund btedly con hected with their high temperature. In order to get the best results, there- fore, from experiments in the formation of starch in the leaves of potted steenhouse plants, it is necessary to keep the plants at a temperature not exceeding 22° C., and to insure this it is well to keep them in diffuse rather than in direct sunlight. It will be of interest to compare these results with those obtained by Sacus for outdoor plants, as described in his classical 3 Physiology 1: 321. 4 Ges. Abhandl. 360. 228 BOTANICAL GAZETTE [SEPTEMBER paper.5- He found that the rate of the disappearance of starch from the leaves increases with the temperature. When the nights were very warm, some plants (Nicotiana, Phaseolus, Juglans, and others) completely emptied their leaves of starch in one night. But after cool nights, 6°-9° C., there was no perceptible loss of starch in some, and the disappearance was incom- plete in others. SaAcus found also that the amount of starch present at any time of the day is affected by temperature. At a temperature of 20°-25° C. the quantity of starch in the leaves increased steadily from morning until evening. But on hot afternoons at a temperature of 30°-35° C. the leaves of Helianthus contained less starch than in the morning at 8 o’clock. The reason for this phenomenon is found in the fact that translocation from the leaf into the stem increases with rising temperature more rapidly than photosynthesis. All of these considerations emphasize the important pre- caution that to obtain the best starch formation in leaves, the temperature should not be permitted to rise above 20°-22° C., which is apparently the optimum for this process, as it is for the best general health of such plants as are used in these studies. Also it must be remembered that plants cannot give good results in this or any physiological experiment, when suffering from previous starvation, as in the case of pot-bound plants or those which have been kept in darkness for a long time; when suffering from over-stimulation from high feeding, or from being kept at too high temperatures; and when they have passed their grand period of growth. Asa rule plants, and particularly annuals, are in their best condition just before flowering —SoPHIA EcKERSON, Smith College. THE MORPHOLOGY OF RUPPIA MARITIMA—A CRITICISM ¢ In section D, “Function of the root,” Graves (p. 113) has wandered be- yond the natural limits of his paper as a morphological study, and while the propriety of this is perhaps questionable, the basis for this criticism is that this section D contains a statement which I think is an unwarranted mis- interpretation of some of my own writings, and alse . statement that would leave most readers misinformed. I wish first to consider the following: “On the other hand, Ponp’s experiments? fail to show conclusively whether or not water and dissolved salts are absorbed by the part of the plant above 5 Arbeit. Bot. Inst. Wiirzburg 3:1 ff., as cited in Ges. Abhandl. 354-387- ® Graves, A. B., The ane ga) of Ruppia maritima. Trans. Conn- Acad Arts & Sciences 14:59-170. ‘7 Ponp, Raymonp H., 3 biological relation of aquatic plants to the substratum U. s. Fish Commission Repod 1903:483-526. 1905. 1909] BRIEFER ARTICLES 229 the soil.” Being somewhat uncertain as to the intended meaning of this statement, I have learned by correspondence that Graves believes that in my paper I have committed myself to the notion (in the absence of con- clusive evidence) that the larger submerged and rooting water plants derive their mineral food exclusively from the soil, and that there is no absorption of mineral food by organs other than the roots. Such a notion I have never held and do not consider my paper as warranting or encoura- ging such an interpretation. My efforts to force certain species to live and grow in nutrient solutions and without a substratum were not continued to a satisfactory conclusion, and for that reason I remained noncommittal on the possibility of absorption by the other organs of the plant. My general conclusion was that certain species which were tried were found to be dependent upon their rooting in the soil for optimum growth and cannot survive a single season if denied a substratum of soil. Whatever the absorption by the organs other than the roots amounts to (in the species tried), it is so small that the species would probably become extinct if forced to depend upon it exclusively under otherwise natural conditions. Looking at section D as a whole we find that every paragraph is general in its scope and treatment. GRAVES tes four reasons for not placing too much emphasis “on the absorbing capacity of the root.”” One of the reasons is “‘the total lack of branches and slenderness of the roots.” I think any reader would infer that submerged plants have slender roots without branches. So far as I know the statement is correct so far as the “slenderness” is concerned but’in my paper (/. c.) there is a section on factors influencing the development of lateral roots Speculation as to the relative importance of absorption by the roots of submerged plants as compared with that in the case of land plants is of little value. I refer particularly to the statement by GRAvEs as follows: ‘In brief, the absorption carried on by the roots of submerged plants and the importance of this function in the economy of the plant is much greater than is implied by ScHENCK—but, on account of the peculiar environ- mental conditions of submerged plants, it can never equal in importance the absorption of the roots of land plants.” Tf the submerged species are as dependent upon rooting in the soil ne my Tesults show, the so-called absorptive function of the root is a vital necessity and it certainly is not more than this for land plants —RAYMOND OND. CURRENT LITERATURE BOOK REVIEWS Bacteriology, general and special Although bacteriology in the past decade or more has developed to such an instruction in the subject-matter relating to the activities of those organisms that are of especial moment to him; but in our larger universities the time is ripe for the presentation of the subject of bacteriology from the standpoint of the student of general science. A course of training in general bacteriology is as essential in supplementing a general course in biology as is general chemistry. ‘The works of De Bary and FiscHer served as a suitable foundation in their day for the treatment of bacteria from the biologic viewpoint, and there is great need that such works be brought down to date. Dr. JorDan, the author of a recent textbook of general bacteriology, has had an unusual opportunity, by training and position, to develop a strong course 10 this subject; yet one cannot help feeling that even in a university atmosphere, * Jorpan, Epwin O., A textbook of general bacteriology. 8vo. PP» 557° Ass: 163. Philadelphia: W. B. Saunders Co. 1908. $3.00. 230 59 ae ae Po ee a S 3 7 4 ' Te oN eat ee ei ps ee GN AG ee 1909] CURRENT LITERATURE — 231 receive adequate treatment. Bacteriology will never attain its true position as a member of the sisterhood of biological sciences until some one of its devotees will sacrifice his time to prepare a comprehensive text that presents the bacteria in their relations as living things, rather than as capable of affecting prejudicially or otherwise man and beast. Special fields may well receive special treatment, with such summary of general matter as may be absolutely necessary to enable the special class of students to handle the subject. While the volume fails somewhat to meet our anticipations and is hardly adequate from the biologic point of view, the admirable presentation of the medical part of the volume shows careful work.. The addition of chapters on the pathogenic Trichomycetes, Blastomycetes, and Hyphomycetes, as well as the disease-producing protozoa and diseases of unknown etiology, will be helpful to the medical student in correlating many of the recent advances in microbiology. With the rapid widening of the scope of study relating to the microparasites, we shall soon be driven to the adoption of the French term “microbiology,” rather than the more restricted German title of bacteriology.—H. L. RUSSELL. The eight years which have elasped since the publication of the first edition of Conn’s Agricultural bacteriology have been years of rapid advancement in all lines of bacteriological activity. A second edition? finds much new material to be incorporated. he author in his preface admits that the limitations of the term agr cultural bacteriology are puzzling. The farmer has most of the city problems of sanitation in miniature and many more in economic bacteriology. The prevention of infec- tious disease in man and animals; farm engineering with its problems of sanita- tion, water supply, and sewage disposal; the function of bacteria in the produc- tion of butter and cheese; the conservation of the soil by encouraging the growth of beneficial bacteria; the part which bacteria play in the curing and prepara- tion of food for man and animal—these problems range over practically the whole domain of bacteriology. A text which attempts to cover such a field in a little more than three hundred pages must of necessity be an outline merely and not an exhaustive treatment of the subject. Each chapter could be easily elaborated Into a volume. In make-up the volume has improved. The pages have been reduced from 412 to 331 in number. The illustrations have been numbered and many old — replaced by better. Part, at least, of the decrease in size is due to the elimination of the references to literature found at the end of each chapter in the first edition. The text has been entirely rewritten, though the main divisions have remained as before. The revision has resulted in increased conciseness and clearness of expression. The discussion of bacteria and the nitrogen problem is excellent for use in an agricultural high school, but seems rather inadequate as a presenta ore Of the subject to college students with two or more years of training In chemistry areaner . , it . x+331- figs. 64. “ep ONN, H. W., Agricultural bacteriology. Second edition. pp hiladelphia: P. Blakiston’s Son and Co. 1909. $2.00. 232 BOTANICAL GAZETTE [SEPTEMBER and biology. A chapter on bacteria and soil minerals has been added. Tuber- culosis is the only disease which is treated at length. The treatment of acquired immunity is misleading, in that vaccination is the only method of conferring immunity which is discussed, and the natural inference is that diphtheria and other diseases are thus treated. Antitoxins are not mentioned. A part of a chapter on fungus diseases of plants shows plainly the effect of too much con- densation. The characterization of wilts, rusts, etc., on page 295 is unscientific and inaccurate. The student can gain little by a mere list of names of hosts an parasites such as this chapter contains. ‘There is much that might be eliminated to make room for more adequate treatment of other subjects. As an introduction to the subject for the general reader or for the high-school student the volume is excellent; as a college text, however, it seems inadequate——R. E. BUCHANAN. NOTES FOR STUDENTS Current taxonomic literature-—R. Hdroip (Bot. Jahrb. 42:251-334- 1909) presents a synoptical revision of the American Thibaudieae and carefully tabu- lates their geographical distribution. One monotypic genus (Englerodoxa) and 67 species referred to 17 genera are published as new to science.—G. MASSEE (Annals of Botany 23:336. 1909) has published a new genus (Gibsonia) se * F Ascomycetes; the new fungus was found growing in a drain in North Lancashire, England.—E. A. Fryer (Bull. Soc. Bot. Fr. IV. 9:97-104. pls. 1, 2: 1909) describes several new or noteworthy species of Orchidaceae, some of which are American.—L. A. Dope (ibid. 232-234) has published a new genus (Orias) of the Lythraceae from China—N. L. GarpNer (Univ. Cal. Pub. Bot. 3:37!-375: pl. 14. 1909), under the title “New Chlorophyceae from California,” has publ: two new monotypic genera (Endophyton and Pseudodictyon); a new species Ulvella is also proposed —O. TscHourIna (Bull. Soc. Bot. Genéve II. 1:98-I0I- 1909) has published a new genus (Astrocladium) of the Palmellaceae. The new alga was discovered in the vicinity of Geneva, Switzerland, and is represented by a single known species.—W. BIALOSUKNIA (ibid. 101-104) proposes a new genus (Diplosphaera) of the Pleurococcaceae, to which is referred but one species The alga was isolated from the lichen, Lecanora tartarea, and developed as 4 culture.—G. O. (ibid. 182) records a new species of Xyris from Brazil. V. CaLESTANI (Nuovo Giorn. Bot. Ital. N. S. 15:355-390. 1908), under the title “Sulla classificazione delle crocifere italiane,” recognizes 31 genera for Italy, including one genus (Euxena) published as new to science.—R. PAMPANINI Soc. Bot. Ital. 1908:132-134) describes a new species and variety of Bi sin indigenous to Mexico.—K. K. MACKENZIE (Muhlenbergia 5:53-58- 1999) several species of Carex collected by A. A. HELLER in Nevada in 1908 and describes two new species.—P. B. Kennepy (ibid. 58-61. pl. 2) in continuation of bis ‘Studies in Trifolium” describes and illustrates a new species from Orer W. Fawcert and A. B. RENpLE (Journ. Botany 4'7:122-129. 1909) in contin’ tion of their studies on Jamaica orchids have published 13 new species belonging to various genera and one new genus (Neo-urbania); the new genus is based 0° of y j ! 7 ‘ — FE ee PE ET hore ee 1909] CURRENT LITERATURE 233 Ponera adendrobium Reichb.—J. A. Purpus (Monats. Kateenk. 19:52, 53, 89. 1909) describes and illustratés two new species of Cereus from Guatemala.—F. EIcHLam (ibid. 59, 60) has published a new variety of Mamillaria Celsiana Lem, from Guatemala.—T. S. BRANDEGEE (Univ. Cal. Pub. Bot. 3:377-396. 1909), under the title “Plantae mexicanae Purpusianae,” has published 43 species and one variety of angiospermous plants as new to science, and proposes the following new genera: Setchellanthus of the Capparidaceae, Acanthothamnus of the Celas- traceae, and Dichondropsis of the Convolvulaceae.—H. D. House (Muhlenbergia 5:65-72. 1909) has described 7 new species of American Convolvulaceae and made several new combinations.—B. SCHROEDER (Ber. Deutsch. Bot. Gesells. 27:210-214. 1909), under the title of “Phytoplankton von Westindien,” lists 71 species from West Indian waters, including one new to science.—J. BRIQuET (Ann. Conserv. et Jard. Bot. Genéve II-12:175-193. 1908) has published 10 new species and 4 new varieties of Ranunculus and Geranium from Mexico and South erica.—N. WILLE (Nyt. Mag. Naturv. 4'7:— (reprint 1-21. pls. 1-4. 1909) describes and illustrates a new genus (Wittrockiella) of the Chaetophorales, repre- Sented by a single species, W. paradoxa. e material on which the new genus is based was collected near Lyngor on the southeast coast of Norway. The author Proposes for it the new family Wittrockiellaceae and states that its nearest affinity is with the Chroolepidaceae.—E. HassLEer (Bull. Soc. Bot. Genéve IT. 1:207-212. 1909) proposes a new genus (Pseudobastardia) of the Malvaceae from South America.—H. Curist (ibid. 216-2 36) in continuation of his treatment of the ferns of Costa Rica, for the ‘‘Primitiae florae costaricensis,” has published 27 New species and one monotypic new genus (Costaricia), also 2 new species o Lycopodium.—E. L. Greener (Rep. Nov. Sp. 7:1-6. 1909) publishes 17 new o 4 Jamaica —E, Hasster (ibid. 72-78) has published six new species and varieties of Malvaceae and Leguminosae from Paraguay and proposes a new genus (Psew- Pavonia).—A_ LINGELsHEmM, F. Pax, and H. WavKLER (ibid. 107-114), Seen the title “Plantae novae bolivianae,” have published 20 new species of flowering Plants.—W. Becker (ibid. 123, 124) records two new species of Viola from Peru. —E. Parra (Oester. Bot. Zeits. 50:186-194. pl. 3. 1909) has published several new Cyperaceae, including a new species of Bulbostylis from Bolivia—E. ULE (Verh. Bot. Ver. Brand. 50:69-123. 1909), in cooperation with several specialists, has Published 7° new species of flowering plants from South America, based on Collections made by himself in the region of the Amazon; two new genera are Proposed: C hamaeanthus of the Commelinaceae and Dolichodelphys ne ct pies ceae—p HENNINGS (ibid. 129-136) has described several new fungi, including 234 BOTANICAL GAZETTE [SEPTEMBER a new monotypic genus (Exogone), which the author refers to the Rhizinaceae; the material on which the new genus is based was found growing on partially decayed leaves of cabbage——T. Maxrno (Bot. Mag. Tokyo 23:59-75. 1909) in continuation of his studies on the flora of Japan describes several new species and proposes a new monotypic genus a of the Celastraceae, based on Elaeodendron japonicum Franch. & Sav.—W. SuKATSCHEFF (Jour. Bot. St. Pétersb. 3:124-136. 1908) gives an account of an alga recently discovered in Lake Lunoevo, Russia, for which the author proposes the generic name Lunoevia; illustrations supplement the description—V. L. Komarov (Acta Hort. Petrop. 29:179-362. pls. 5-20. 1909) presents a monographic treatment of the genus Caragana, in which 56 species are recognized, 27 being new to science; the genus has its distribution through central Asia and China.—E. B. Copetanp (Phil. Jour. Sci. 4:1-64. pls. 1-21. 1909), in an article entitled ‘‘Ferns of the Malay- Asiatic region, part I,” including all families of ferns for the region except Hymen- ophyllaceae and Polypodiaceae, recognizes 22 genera, to which are referred 196 species. The genus Cyathea dominates, being there represented by ror species. Each genus is illustrated by reproduced photographs, but from rather fragmentary material.—C. B. Rosrnson (ibid. 69-105) records for the Philippine Islands three species of the Chloranthaceae, of which one is new, and some 55 species of the sec- tion Phyllanthinae of the Euphorbiaceae, of which 21 are new to science:—R. MUSCHLER bes ool 43: Pes 1909); ander the title “‘Sytematische und pflan- Senecio-Arten,” presents a detailed cdnsideration of the genus, as ae pertains to Africa, eee about 500 species, 28 of which are here described for the first time.—H. D. HousE (Ann. N. Y. Acad. Sci. 18:181-263. 1908) presents a monographic treatment of the North American species of Ipomoea, in which 17 5 species and several varieties are recognized, 3° being new. The author gives concise keys, rather full synonomy, and numerous species of Lathyrus from New Masieg aa M. G Cy y of a Drosera hybrid.—Since the dita’ announcement of ROSENBERG’s work on the hybrid Drosera longifolia X rotundifolia, cytologis of have awaited with some impatience the more detailed account, which has ae appeared.’ —_ Besides giving a comparative study of the external features of = two parents and their hybrid, the present paper describes the behavior of < chromosomes in critical phases of the life-history of both parents, and gives extended account of the chromosomes of the hybrid. ss sera OSENBERG, O., Cytologische und morphologische Studien iiber ” pt 4. loner Kungl. Svenska Vetenskapsakad. Handl. 4321-64 pls. 1909 4 a Z * : iiss i aati 1909] CURRENT LITERATURE 235 In D. longifolia there are 40 chromosomes in the nuclei of the sporophyte and _ 20 in those of the gametophyte, while in D. rotundifolia the numbers are 20 and Io respectively. The chromosomes of D. rotundifolia are somewhat smaller, as well as less numerous. The behavior of the chromatin in a hybrid between two such forms is naturally of some importance. In the hybrid, called D. obovata, the nuclei of the sporophyte show regularly 30 chromosomes, the anticipated number, but in the nuclei of spore mother cells the condition is unique. At the metaphase of the heterotypic mitosis in the pollen mother cell there appear 10 double chromosomes, presumably resulting from the pairing of 10 chromosomes of D. longifolia with the 10 of D. rotundifolia. Besides, there are 10 smaller single chromosomes, presumably belonging to D. longifolia. These 10 smaller chromosomes are irregularly distributed; some enter the daugh- ter nucleus at the close of this mitosis, while others remain in the cytoplasm and may organize small nuclei, as in the well-known case of Hemerocallis. The behavior at the second mitosis is similar. The four spores of the pollen tetrad Stick together, so that it is possible to determine the entire number of chromo- Somes in the four nuclei. Counting the chromosomes in the four nuclei and including those of the dwarf nuclei, the number is about 60. In any given spore the number ranges from ro to 15, with 14 the most frequent. In a preliminary Paper, ROSENBERG concluded that two of the spores of a tetrad belonged to D. longifolia and two to D. rotundifolia. This conclusion is now withdrawn, and differences in the size of spores is attributed to differences in the number of chromo- somes. Sometimes a generative cell is formed, but usually the contents of the Spore begin to disorganize before this stage is reached. At the time of shedding, the pollen grain has a normal exine, but the contents are usually dead. In the formation of four megaspores from the mother cell the behavior is very similar to that just described. Occasionally, there is a well-developed embryo Sac, but in most cases disorganization begins before the four-nucleate stage 1s reached. ROSENBERG crossed the hybrid D. obovata with D. longifolia, and while usually there was no result, he obtained a few embryos. These contained at least 33 chromosomes, and in one case 37 were counted. The theoretical number would The principal conclusions are (1) that the chromosome is an individual one of the cell, and (2) reduction of chromosomes is brought about by a fusion of the chromosomes of the two parents.—CHARLES J. CHAMBERLAIN. of Alchemilla. In addition to finding that the mildew on Alchemilla is confined to species of this genus, he also claims to be able to distinguish minor biological species” within this genus of host plants. For example, conidia a *Srerver, J. A., Die Spezialization der Alchemillen-bewohnenden Sphaerotheca Humuli (DC.) Burr. Centralbl. f. Bakt. etc. 212:677-726. 1908. 236 BOTANICAL GAZETTE [SEPTEMBER from A. pastoralis and A. flexicaulis are alike in infecting capacity, except that conidia from the former will only partially infect A. pubescens, and not A. alpigena at all; while conidia from A. flexicaulis partially infect A. alpigena, A. pubescens being entirely immune. Another case is that of the mildew on A. impexa which does not infect A. alpina vera or A. nitida, while conidia from A. pastoralis par- tially infect these hosts. Otherwise the two mildews are alike. STEINER further found that conidia from species of the Vulgares group will not produce full infec- tion on alpine species, although conidia from alpine species produce full infection on the Vulgares species. STEINER supposes that the mildew on the alpine species came originally from Vulgares species and is only partially adapted to the ete osts. He also believes that the appearance of the mildew on alpine species 1S due to unfavorable environment. me STEINER also claims to have found “‘bridging species;” for example, conidia from A. nitida infect A. impexa but not A. fallax, while conidia from A. 1mpexd will infect A. fallax. Thus the mildew is carried over from A. nitida to A. jallae through A. impexa. Similarly, A. pastoralis and A. impexa transfer the mildew from A. connivens and A. pubescens to A. micans. In addition to the fact that only a few tests were made, STEINER does not tell us what are the infecting powe™ of the mildews produced in this way on A. micans and A. fallax. His conclusions would be more convincing if based on a larger number of tests. A large number of foreign infections also occurred in his experiments, no less tha 71 foreign infections occurring in a total of 380 tests. The results are presented very clearly by means of a series of well-devised diagrams.—GEorGE M. REED. Cytology of Florideae.—Cytological studies on the Florideae have ge comparatively rare, partly on account of the difficulty in securing material, bu principally on account of the difficult technic. Quite recently KursSANOW es publisheds the results of his studies on three different forms of red algae: ue minthora divaricata, Nemalion lubricum, and Helminthocladia purpurea. ue investigations did not deal with nuclear details, but rather with the morphology ° fertilization of the carpogonium, the development of carpospores, and the aes of the chromatophores. : : He failed to find a nucleus in the trichogyne of Nemalion and iceman the trichogyne in these forms seems to be an extension of the carpogonium. believes that such a condition is found only in the simplest forms of red srt and agrees with the reviewer that a trichogyne with a nucleus, and yet W! 6 ; a partition wall between it and a carpogonium, as in Polysiphonia, may The forerunner of the multicellular trichogyne found in the Laboulbeniaceae- : spermatium (sperm) has a single nucleus, agreeing with the reviewer's ages tion of Polysiphonia. He thinks that a uninuclear condition in the spet™ ults perhaps be universal in red algae. In Nemalion, contrary to WOLFE’S Tes the chromatophore has, in its center, a well-formed pyrenoid which is com ; 473-330" 5 Kurssanow, L., Beitrige zur Cytologie der Florideen. Flora 99331133 pls. 2, 3. Ig09. Thar? ee eee, 1909] CURRENT LITERATURE 237 of two parts, a central portion and the surrounding zone. The pyrenoid is influenced by its environment, and easily becomes swollen and dissolved, leaving - vacuoles in its place. Such a compound structure of the pyrenoid is shown only in the stained preparation, and when it is not differentiated with stains the pyrenoid appears quite homogeneous. ScHuitz’s description of the pyrenoid as a homo- geneous body may perhaps be based upon the unstained material—Snicto YAMANOUCHI. Karyokinesis in Oedogonium.—Since STRASBURGER’S and KLEBAHN’s work on Oedogonium, there had been little published on mitosis in this form until WISSELINGH’S paper appeared. STRASBURGER’s material was O. tumidulum Kg., EBAHN’S O. Boscii Witte, and WissELINGH’s material was O. cyathigerum Witte, fixed in Flemming’s solution. After being left in the solution for one day, it was treated with 20 per cent. chromic acid. By the action of the Flem- ming solution and the chromic acid solution, the cell wall and cell ¢ontents become entirely dissolved, and the nuclear membrane is also dissolved by the action of 20 per cent. chromic acid ‘solution. The chromosomes during mitosis were studied in their isolated condition. The chief points of interest are as follows: The mitosis in Oedogonium agrees with that of higher plants; the development of chromosomes out of the nuclear network, the formation of the nuclear plate, the longitudinal splitting of the chromosomes, the reconstruction of daughter nuclei seem like these pr in Fritillaria and Leucojum, two forms which were also studied by von WISSE- LINGH. In Oedogonium, the chromosomes, 19 in number, and differing greatly from one another in length, are connected by fine fibrils, The nucleolus does not take part in forming chromosomes, but disappears at the beginning of mitosis, and there appear in daughter nuclei new nucleoli, which later unite into one.— SHIGEO YAMANOUCHI Mycorhiza.—PEKLo announces in a preliminary paper’ the results of his Studies on the epiphytic mycorhiza of Carpinus and Fagus, with brief reference also to the endophytes of Alnus glutinosa and Myrica Gale. Tn Carpinus, asa reaction to the penetration of the tissues of the young rootlet, ‘annins increase (as the author has also determined for Monotropa*), and this Testricts the fungus to the intercellular spaces. Nourishing itself partly on this Slucoside and other foods in the cortex, the fungus forms the jacket, the outer- most hyphae of which often die. Isolation of the fungus was finally accomplished by using a decoction of old thick mycorhizas, which proved very specific for the Sa easy oe ° WISSELINGH, C. von, Ueber die Karyokinese bei Oedogonium. Beih. Bot. Centralbl. 2 32139-156. pl. 7. 1908. "PEKLO, J., Beitrage zur Lésung des Mykorhiza-Problems. Ber. Ie icosua Bot. Gesells. 27 3239-247. 1909. : ie a eo » Die epiphytischen Mykorhizen nach neuen Untersuchungen. I. M _ Ypopitys L. Bull. Bohm. Akad. Wiss. 00:000. 1908. 238 BOTANICAL GAZETTE [SEPTEMBER infecting fungus. In this the inner hyphae began to grow and broke through the outer layers, and on this mycelium, whose origin was clear, conidiophores and conidia arose within three days. These showed it to be a Penicillium (Citromyces) very like P. geophilum, and similar results were reached with Fagus. Fungi 0 this group were also found in the forest soil where mycorhiza of Fagus was abun- dant. Carpinus was not available for experiments on reinfection, but a consider- able number of young roots of a two-year-old Fagus showed infection from pure cultures of the Carpinus mycorhiza, as well as from several other species of forest Penicillia.—C. R. B. Respiration.—For about a dozen plants Mme. MaicE has determined the amount of O, fixed and CO, evolved by the stamens and pistils as compared with an equal weight of leaf tissue, both in air and in pure hydrogen.? She finds both aerobic and anaerobic respiration, tested thus, to be much (2-18 times) more active in the floral organs than in the leaf; and, with one exception, more vigorous in the pistil than in the stamen, and in the anther than in the filament. These results confirm the early ones (1822) of DE SaussuRE, as to the relative rate of respiration of the floral organs and the leaves; but DE SaussuRE found stamens more active than pistils. For the conciseness of this paper Mme. MAIcE is much to be commended. JeNsEN?? finds that the alcoholic fermentation of sugar proceeds by two Stages and he therefore predicates two enzymes, glucose being split by dextrase (glucase ?) into dioxyacetone and this by “‘dioxyacetonase” into CO, and alcohol. But in respiration, with oxidase and free oxygen present, the dioxyacetone, pro- duced as in fermentation, breaks up into CO, and water, the main end-products of aerobic respiration.—C. R. B Transpiration.—Sampson and ALLEN, declaring that too little account has been taken of the effect of physical factors on transpiration, furnish further data on this subject.t* Comparing evaporation from equal areas in equal times wid find that there is little variation for plants of the same species under the same —. ditions of development and exposure; that of the same species the sun Sn evaporates 2—4 times as much as the shade form, whether the two are tested in the sun or shade, a difference which they ascribe chiefly to the greater pees stomata in the sun form (20-60 per cent.); that the increased evaporation = t altitude, caeteris paribus, is due to lower pressure and not to differences 1 pe or humidity; that generally acid solutions accelerate and alkaline solutions re ; evaporation, but without relation to concentration; that evaporation 1S a 9 MaIcE, Me. G., Recherches sur la respiration de I’étamine et du pistil. Rev Gén. Bot. 21: 32-38. 1909. ‘© JENSEN, P. Boysen, Die Zersetzung des Zuckers wahrend des RespirationsP zesses. Ber. Deutsch. Bot. Gesells. 26a:666, 667. 1908. 't Sampson, A. W., AND ALLEN, Louise M. Influence of physical transpiration. Minn. Bot. Stud. 4:33-59. 1909. factors 0? oe ee ee ee a eee er ee en LO RI TOT en ae 1909] CURRENT LITERATURE 239 from plants in coarse than in fine soils; and that a “bog xerophyte,” Scirpus lacustris, loses about twice as much water as Helianthus annuus, on account of its loose structure, the air spaces being estimated at 80 per cent. of the total volume and the internal surface as 15 times the external.—C. R. B. Anthocyan.—On the vexed question of the formation of anthocyan, ComBEs furnishes‘? first a very clear and compact summary of the previous researches. e then demonstrated that the close relations between the accumulation of carbohydrates and the formation of anthocyan, pointed out by the researches of OverToN and Mo iiarp on artificially nourished plants, exist also in nature, however the pigmentation is provoked. The insoluble carbohydrates behave differently, according to the occasion of the pigmentation; but the sugars, gluco- sides, and dextrins behave alike : all cases, the two former varying in amount directly as the anthocyan, the dextrins diminishing as the sugars and glucosides increase. The foncluble aie consequently, appear not to share directly in the formation of the red pigment. Comes concludes that the antho- cyans, which are probably cyclic glucosides, are formed at the expense of neither preexistent sugars and glucosides nor chromogens, but arise at the same time as other glucosides, as part of the general accumulation of such bodies.—C. R. B. Chlorophyll bodies.—Morphological distinctions between chlorophyll bodies, found in a great number and variety of plants, have been pointed out by D’ARBAU- MONT,'3 who divides them into two categories, chloroplasts and pseudochloro- Plasts. The former, held to be morphologically superior, seem to include the bodies usually recognized under that name, without admixture of the latter, om which they are distinguished by not swelling in water (at least im situ), and by not being stained, with rare exceptions, by acid aniline blue. The pseudo- chloroplasts, on the contrary, usually swell in water and become vividly colored in the stain, They are of four types, all small, more or less varied in shape, with different degrees of green coloration, and variously intermixed. The mem- bers of the two categories are formed in the same way, either with or without the cooperation of starch,'4 and both, without reference to their mode of origin, may or may not form starch.—C. R. B. ro re of Symplocarpus.—In an investigation of Symplocarpus pres RosENDAHL'S has obtained the following results: the primordia sea pein se ‘? ComBes, R., Rapports entre les composés ae et Ja formation de grates Ann. Sci. Nat. Bot. IX. 9275-303. 1909 3 D’ARBAUMONT, J., Nouvelle contribution a l’é conte des corps chlorophylliens. Nes Sci. Nat. Bot. IX. 9: 197-229 '4Cf. Betzune, E., Nouvelles vitae sur l’origine des grains d’amidon et des grains 7 paar Ann. Sci. Nat. Bot. VII. 13:17. 1891; Jour. de Bot. 9: we To2. 1895. OSENDAHL, C. Orro, Embryo sac development and embryology nee espa Minn. Bot. Studies 4':1-9. pls. I-3- 1999- 240 BOTANICAL GAZETTE [SEPTEMBER appear 18-20 months before the pollination period, and the ovules are formed late during the season preceding pollination; the single archesporial cell produces four distinct megaspores; an antipodal tissue of a considerable number of cells with large nuclei is developed; endosperm formation begins with free nuclear encroaches upon the integuments and the chalaza;-a filamentous proembryo (2 or 4 cells) becomes club-shaped to ovoid, and a short suspensor of several rows _ of cells is differentiated from the usual monocotyledonous embryo; in its growth the embryo completely destroys the endosperm and all other ovular structures, and comes to lie naked in the cavity of the ovary, so that there are no seeds in the ordinary sense.—J. M. C, Morphology of Caulophyllum.—The seed and seedling of Caulophyllum thalictroides have been studied by Butrers,'® with the following results: the fleshy testa incloses a very hard endosperm, which has almost completely destroyed the inner integument; the proembryo is massive and pear-shaped and the cotyle- dons appear late; the first season’s growth after germination is usually entirely subterranean, the cotyledons together forming an effective haustorium; the first leaves are usually scalelike and inclose a winter bud; each cotyledon sends three vascular bundles into the hypocotyl, which finally form a tetrarch root; secondary thickening takes place in the hypocotyl, resulting in the formation of a continuous j zone of xylem about the pith —J. M. C. # we ee eee sian Temperature and locomotion. TEODORESCO reports'? movements in certain = organisms at temperatures far lower than have heretofore been recorded. Thus he found zoospores of Dunaliella motile down to temperatures of oe —22° 5 C., and others at —5° to —12°7 C. The limits vary with species and even with individuals. There seems to be much more activity in winter, even aa freshwater organisms, than has been supposed.—C. R. B _ Carbon monoxid.—Krascuénnikorr, after a careful series of a reports*® that CO cannot be used by green plants to form carbohydrate. * view of BoTTOoMLEY AND Jackson,*? which was really not adequately suppo oe by their experiments, the only ones interpreted in favor of such use, is dis negatived.—C. R. B. ira © BUTTERS, FREDERIC K., The seeds and seedling of Caulophyllum thali Ee Minn. Bot. Studies 4': 11-32. pls. 4-10. 1909. - ¥ ‘7 TEopoREsco, E. C., Recherches sur les mouvements de locomotion der sig nismes inférieurs aux basses températures. Ann. Sci. Nat. Bot. IX. 9:23!-27+ Bate ‘8 KrascHENNIKOFF T., La plante verte assimile-t-elle oxyde de N° Rev. Gén. Bot. 21:177-193. pl. 10. 1909. i '9 Proc. Roy. Soc. Lond. 72: 130-131. 1903. ae Aiticics : Pas TH : = New Normal Appin Ui Tbe Botanical Gazette a Monthly Journal Embracing all Departments of Botanical Science ted by Joun M. CouLTeR and CHarLes R. BARNES, with the Rat of other members of the botanical staff of the University of Chic Issued October 21, 1909 ol. XLVII CONTENTS FOR OCTOBER 1909 No. 4 EMBRYO SAC OF HABENARIA (wITH TWELVE FIGURES). William H. Brown = 241 BE INFLUENCE OF TRACT ae ON THE oe ee Acs sinccharmipbeeie wave dhs Sar » IN STEMS. John S. Bord: 251 E MODIFIABILITY OF a ION IN batcrhiss SEEDLINGS siaeond FIVE FIGURES), Joseph VY. Ber, 275 REMARKABLE duane yor EIGHT FIGURES). George F. Atkinson - — - - 283 NDESCRIBED PLANTS FROM GUATEMALA AND OTHER CENTRAL AMERICAN REPUBLICS. XXII. John Donnell Smith 294 FER ARTICLES 3 NEw oe esha irik FOR USE IN PLANT PuYstoLodY Recta TWO Besar acs W. f EF. Gan “ 301 IRRENT as BS BOOK REVIEW. R 2 3 i 2 2 a : G Z F - 306 ANISOPHYLLY. DESERT VEGETATION. ANIMAL GALLS. 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A table os approximate anes oi separates po ON an worday blank which accompanies the sare copy will ibe sent os oe August 21, 1895, at the Post-Office at Chicago, as second-class matter, under Act of ean i SP ascrs in he wae eet VOLUME XLVIII NUMBER 4 BOTANICAL GAZETTE OCTOBER 1909 THE EMBRYO SAC OF HABENARIA* Wittram H. BROWN (WITH TWELVE FIGURES) The present investigation was made on Habenaria ciliaris (Michx.) R. Br, and H. integra (Nutt.) Spreng. The development of the two species is very much alike and the same description will apply to both. The material was fixed in medium chromacetic and the sections were Firs = Se Megaspore mother cell in apex of llus.—Fic. 2. Megaspores.—Fis. 3. division of functional megaspore and three degenerating megaspores. cut 10 thick and stained with Flemming’s triple or Haidenhain’s Iron alum hematoxylin. T The ovule of Habenaria is anatropous and has two integuments. h he archesporium differentiates in the apex of the nucellus as a single ypodermal cell ( fig. 1), which is the terminal cell of a row surrounded No “Contribution from the Botanical Laboratory of the Johns Hopkins > scbieganted - Io, 24 242 BOTANICAL GAZETTE [OCTOBER only by the epidermal layer. The archesporial cell without dividing functions as a megaspore mother cell, which divides to two daughter cells, which in turn divide to form four megaspores. The last division may be simultaneous in both daughter cells, but usually it is delayed in the one nearest the micropyle (/ig. 2). Soon after the formation of the megaspores the chalazal one begins to enlarge at the expense of the other three, which soon degenerate. Before this degeneration has proceeded far the nucleus of the function- ing megaspore divides (jig. 3) and the two daughter nuclei remain t.—Fic. 5. Bight —Fre. 6. ash a, degenerating Fic. 4. Nuclei of four-nucleate embryo sac dividing to eigh nucleate embryo sac: s, synergids; e, egg; a, antipodals; , polar nuclei bryo sac with fusing polar nuclei; 9, polar nuclei; s, synergids; e, egg; antipodals.—Fic. 7, Young embryo and degenerating endosperm nucleus. in the polar positions in the enlarging sac. Each of these two nucle! by two successive divisions gives rise to four, so that the mature sac contains eight nuclei (fig. 5). As the sac continues to enlarge, the nucellar cells which surrounded the four megaspores degenerate, so that at about the four-nucleate stage the sac comes to lie against - inner integument. At the last division of the embryo sac nucle! a two spindles in each end are arranged approximately at right ang ci to one another (fig. 4). As is usual, the transverse spindle in the micro pylar end gives rise to two synergids, while the longitudinal on¢ ger the egg and the micropylar polar nucleus. In the chalazal oe longitudinal spindle gives rise to the antipodal polar nucleus and = CRs o 2 en ee ay SY. 3 Ig09] BROW N—EMBRYO SAC OF HABENARIA 243 antipodal, while the other spindle forms twoantipodals. Walls cutting off the egg, synergids, and antipodals are formed on fibers connecting the nuclei. Owing to their position nearer the center of the sac, the polar nuclei are left free in the cytoplasm (fig. 5), as has been pointed out by STRASBURGER (?05) for Drimys Winteri. After their formation, the egg and synergids enlarge considerably, while the antipodals soon degenerate ( jig. 6). When the egg and synergids have about reached their mature size, the polar nuclei fuse (fig. 6). No cases were observed in which the polar nuclei were in con- Fics. 8-1o. Older embryos: s, suspensor; e, embryo. tact without fusing, as have been described for other forms by STRASBURGER (700) and Nawascutn (’00). The pollen tube comes through the micropyle and discharges the two male nuclei into the embryo sac. One of these fuses with the egg, while the other fuses with the product of the fusion of the polar nuclei to form the primary endosperm nucleus. This enlarges somewhat, but without dividing begins to degenerate at about the time of the first division of the fer- tilized ege (fig. 7). ee The first division of the fertilized egg is transverse to the longitudi- Nal axis of the embryo sac. Of the two resulting cells the chalazal one 244 BOTANICAL GAZETTE [ocTOBER forms most of the embryo, while the micropylar one gives rise to the suspensor and a small part of the young embryo. The second division ( fig. 8, wall 2) is in the micropylar cell and is also transverse; the third division (jig. 8, wall 3) is in the chalazal cell and is longitudinal. Divisions continue in the descendants of the micropylar cell until a row of about eight cells is formed (fig. ro). The seven of these which are nearest the micropyle make up the suspensor, while later on the other one divides to form part of the embryo ( fig. 11). The first division in this cell may be either transverse or longitudinal. When the row of cells derived from the primary micropylar cell has become four or more cells long, trans- verse segmentation begins 12 the descendants of the chalazal cell (fig. 9), so that this be- comes cut into quadrants (Jig: Fic. 11. Still older embryo drawn on a ro). Up to this stage the smaller scale; the suspensor has elongated. have , sor —Fic. 12. Many-celled embryo. embryo and suspen - remained within the embryo sac Cavity, but now the cells of the suspensor elongate and the free end of the suspensor is pushed through the micropyle out beyond the integuments (cf. shape of cells in figs. ro and 11). The cells of the embryo undergo further division and form a globular mass; fig: - represents a young embryo in which walls 1 and 3 correspond to 1 an 3 of figs. 8-11. Discussion MEGASPORES In Habenaria the megaspore mother cell divides to two eet cells and each of these divides to two megaspores. The nee” the daughter cell nearest the micropyle is usually delayed until wai that in the daughter cell nearest the chalazal end. If this delay ae | carried a little farther, we should have the condition described 4 Sa a 4 ‘ 1909] BROW N—EMBRYO SAC OF HABENARIA 245 several other orchids (WARD ’80, STRASBURGER ’84), which have only three megaspores. In Cypripedium (PAcr ’08) the daughter cells of the megaspore mother cell do not divide, but one of them forms the embryo sac. In this case the question arises as to whether the division of both daughter cells has been omitted, in the way indicated for one of them in Habe- naria, and the place of the second “reducing division” changed to the embryo sac mother cell (the cell within the walls of which the embryo sac is organized); or whether the first two nuclei of the embryo sac are, as Miss Pacer calls them, megaspore nuclei. In favor of the latter view it may be said that the “completion of chromosome reduction” which takes place in the division of the daughter cell is necessary to the normal development of the embryo sac. COULTER (’08) thinks that because chromosome reduction, which is usually associated with megaspore formation, is necessary that megaspore nuclei cannot be omitted. On the other hand, the place of reduction is not always constant, even in nearly related plants, as in the case of Nemalion (WoLFE ’04) and Polysiphonia (YAMANOUCHI 705). In Nemalion the fertilized egg divides to carpospores and, according to WOLFE, reduction takes place in their formation. In Polysiphonia reduction does not take place in carpospore formation, but the carpospore oe minates to a plant with the diploid number of chromosomes. This plant bears not carpospores but tetraspores, and reduction takes place in the division of the tetraspore mother cell. In speaking of Poly- siphonia, Yamanoucut says: “The tetrasporic plants may have arisen by a suppression of the reduction phenomena in connection with the Carpospore, so that it germinates with the sporophytic number of chro- Mosomes. . . . . The period of chromosome reduction would be thus postponed from the carpospore to a later period in connection with the newly formed plant.” If, as seems probable, the place of reduction has been changed among the red algae, it is reasonable to Suppose that it may also have been changed in some angiosperms, and “specially if the structure in which it normally occurred had been left out of the life-history of the plant. The leaving-out of the division of the the mother cell into megaspores would simply be the completion of a tendency toward the reduction in the number of divisions of the arche- Sporial cells from the condition in the ferns (where it divides a number 246 BOTANICAL GAZETTE [OCTOBER of times) to such a condition as Habenaria where the archesporial cell without dividing functions as a spore mother cell. The only way in which we can claim that megaspore nuclei must accompany chromosome reduction is by defining a spore mother cell as that cell in which reduction is initiated and spore nuclei as the nuclei resulting from the reducing divisions. The logical conclusion of this would be to make chromosome behavior the sole criterion for distin- guishing spores, sporophytes, and gametophytes; but since the four megaspores and embryo sac of Alchemilla (MuRBECK ’o01) may have the diploid number of chromosomes, or the apogamous embryos of Nephrodium (YAMANOUCHI ’08) the haploid number of chromosomes, we cannot regard chromosome behavior as the sole, if indeed the most important, criterion for distinguishing any of these structures. A distinction between the first division of the megaspore and a division giving rise to megaspores is that while in the first case no cell plate is formed on the spindle, in the latter case either a wall or a cell plate is formed on the spindle. This wall may be formed in the embryo sac when this is derived from more than one megaspore, 4S is apparently the case in Peperomia (BRowN ’08). The first division of the embryo sac mother cell nucleus of Cypripedium (PACE ’0 agrees with that of those derived from one megaspore in having 0 cell plate formed on the spindle. ‘ The evidence for either view is inconclusive, but seems to the writer to be in favor of the idea that in Cypripedium the second division 1) megaspore formation has been left out, and the place where “ reduc- tion is completed” changed to the first division of the nucleus of the embryo sac mother cell. Lroyp (’02) and Coutrer (’08) have advanced the idea that when - megaspores are not formed the first four nuclei of the embryo BAC ATE megaspore nuclei. This is probably true in such cases as Lilium (CouLTER and CHAMBERLAIN ’03) and Peperomia (BRowN 708), and as COULTER (’08) suggests in some other sixteen-nuclea bryo sacss but if the ideas brought forward here concerning Cypripedium 4t° correct, it need not be of universal application. CAMPBELL ('09)» however, seems to think that even the embryo sacs of Lilium and Peperomia are not derived from more than one megaspore. In discussing the view of CouLrer (’08) that when the megaspore +a c 1909] BROWN—EMBRYO SAC OF HABENARIA 247 mother cell does not divide the first four nuclei of the embryo sac are megaspore nuclei, and of BRown (’08) that the embryo sac of Pepero- mia is composed of the descendants of four megaspores, CAMPBELL (09) says: “The generally accepted view that in such cases as Peperomia and Lilium the embryo sac is a single megaspore formed without previous division from the mother cell can hardly be admitted to have been disproved by these recent speculations.” In speaking of Peperomia, he says that BRown bases his opinion that the first four nuclei of the embryo sac represent megaspores upon the fact that cell walls are formed in the first two nuclear divisions in Peperomia sintensit and cell plates in the same divisions in P. pellucida; while in the third division cell plates are wanting. CAMPBELL says that since in the last division, which gives rise to sixteen nuclei, cell walls are formed, “this seems rather inadequate grounds for assuming that the embryo sac rep- resents four spores rather than a single one.” The presence of the cell walls was not the only reason for thinking that the embryo sac of Peperomia represents four spores; but even if it were, the formation of Walls in the last division would offer no difficulty to such a view, for walls are usually formed at the last division of the embryo sac of angio- sperms and the writer has not been able to find any essential difference between the method of their formation in Peperomia and in Habenaria. Nor would the reduction of the free divisions in the embryo sac to a single one (the third in Peperomia) be a difficulty when we remember that the number of these is often large but quite variable in the gymno- sperms and has been reduced to two in the ordinary angiosperms. The fact remains that unless we assume that the first four nuclei of the embryo sac of Peperomia and Lilium are megaspore nuclei, we have no explanation for the presence of walls in the first two divisions of the ‘mbryo sac of Peperomia and for the absence of these walls in the third division, or for the presence of cell plates on the spindles of the first two divisions of Lilium, features which have been described in no case, So far as the writer knows, in which the embryo sac is formed from one of four megaspores. we CAMPBELL thinks that if the compound nature of the sac of Lilium be admitted, we still have to explain the extraordinary departure of Peperomia from the usual type, but why two such distantly related Plants would be expected to behave alike is not explained. 248 BOTANICAL GAZETTE [OCTOBER It does not seem likely that a primitive embryo sac, as CAMPBELL believes the sixteen-nucleate type to be, has been retained in plants so far examined only in such distantly related genera as Peperomia, Pan- danus (CAMPBELL ’09), Gunnera (ERNST ’08), Euphorbia (MopILEw- SKI 709), and the Penaeaceae (STEPHENS 708); and especially since most of these genera are anything but primitive in other respects, and the embryo sac is in most cases derived from a spore mother cell which, as CAMPBELL says, can hardly be regarded as a primitive feature. ENDOSPERM NaWASCHIN (700) finds that in Phajus and Arundina there is no fusion of the polar or second male nuclei, and he attributes the lack of endosperm to this cause. STRASBURGER (?00) has shown that in several European orchids this fusion may or may not take place, but . in either case there is no division to form endosperm. He concludes from this that the lack of endosperm is not due to the failure of the nuclei to fuse. The condition in Habenaria, where there is no endo- sperm, although the fusion nucleus is of constant occurrence, 15 4 confirmation of this view. In contrast to Habenaria, endosperm may be formed in Lemna (CALDWELL ’99) without a fusion of the polar nuclei. , In the aposporous embryo sac of Hieracium (ROSENBERG 06) polar nuclei with the diploid number of chromosomes may fuse 1 form the endosperm nucleus. In all known sixteen-nucleate sacs all of the nuclei not cut off by walls fuse to form the primary endo- sperm nucleus. In Peperomia hispidula (JOHNSON ’07) pees fourteen of these fusing nuclei; while in P. pellucida (JOHNSON 00) and P. sintensii (BROWN ’08) there are eight; in the Penaeaceae (STEPHENS ’08) and Euphorbia procera (MopILEwskI ’09) there are four; and in Gunnera (ERNsT ’09) seven. The fact that in Habenaria the fusion of the polar and second male nuclei does not result in the formation of endosperm, while in eRe endosperm is formed without this fusion, taken together with the 2 that the primary endosperm nucleus may be formed by the fusion 0" @ variable number of nuclei or of nuclei with either the diploid oT ai loid number of chromosomes, seems to strengthen Se (?05) view that the endosperm is not a sexually produced embryo 1909} BROWN—EMBRYO SAC OF HABENARIA 249 that the fusion of the nuclei is connected with the fact that the nuclei have ceased developing and are in the same cell cavity. Summary The archesporium of Habenaria arises as a single hypodermal cell, which without dividing functions as a megaspore mother cell. The mother cell divides to two daughter cells and each of these to two megaspores. The division of the daughter cell nearest the micro- pyle is usually delayed. In some cases an embryo sac is probably formed from more than one megaspore; but the condition in the orchids, where there is a gradual reduction of the divisions of the megaspore mother cell without an indication of walls in the embryo sac, indicates that megaspore forma- tion may be omitted and the place of reduction changed to the first division of the nucleus of the embryo sac mother cell. The embryo sac of Habenaria contains eight nuclei: an egg, two synergids, two polar nuclei, and three ephemeral antipodals. The primary endosperm nucleus is formed by the fusion of the polar and second male nuclei, but degenerates without dividing. The absence of endosperm in many orchids offers no support to the view that the endosperm is a sexually produced embryo. The fertilized egg gives rise to a long suspensor and a globular embryo, : My thanks are due to Professor D. S. JoHNSON for helpful sugges- tons and criticisms. Jouns Hopxins UNIVERSITY Baltimore, Maryland LITERATURE CITED 1. Brown, W. H., The nature of the embryo sac of Peperomia. Bor. GAZETTE LL, O. W., On ao tas of Lemna minor. Bot. GAZETTE 27: 37-66. figs. 59. 1899. - Campsett, D. H., The embryo sac of Pandanus. 36: 205-220. es 6 gee 1909. 4. CoULTER AND CHAMBERLAIN, Morphology of angiosperms 80. 1903. ) PEE Bull. Torr. Bot. Club w 250 BOTANICAL GAZETTE [OCTOBER CoutTer, J. M., Relation of megaspores to embryo sacs in angiosperms, Bot. GAZETTE 45:361-366. 1908. . Ernst, A., Zur Phylogenie des FAL ae der Angiospermen. Ber. Deutsch. Bot. Gesells. 26: 419-437. pl. 7. . Jonnson, D. S., On the endosperm and sane of Peperomia pellucida. Bort. GAZETTE 30:1~-11. pl. I. 1900. A new type of ee sac in Peperomia. Johns Hopkins University —- 195:19-21. pls. 5, 6 19 YD, E., The comparative a of the Rubiaceae. Mem. tae Bot. ‘Club 8:27-112. pls. 8-15. 1 . MopitewskI, J., Zur ae von s Euphorbia procera. Ber. Deutsch. Bot. Gesells. 2'7:21-26. pl. rt. 19 . MuURBECK, S., ep eaeee Brabrpobildung in der Gattung Alche- milla. Lunds Univ. Arsskrift 362: No. 7, 46. pls. 6. 190%. . NAWASCHIN, S., Ueber die 3 cocoa ama bei ee Dicotyledoneen. Ber. Deutsch. Bot: Gesells. 18:224-230, i. . Pace, Luna, Fertilization in Cypripedium. ee Gazette 44: 353-374 908. pls. 24-27. 14. gay O., Ueber die Embryobildung in der Gattung Hieracium- Ber. eee Bot. Gesells. 24:157-161. pl. 11. 1906. 15. STRASBURGER, E., Einige Bemerkungen zur Frage nach der “«doppelten Sctudined™ bei den Angiospermen. Bot. Zeit. 58:293-316. 1900. , Die Samenlage von Drimys Winteri und die Endospermbildung bei Aniicinmeniie: Flora 95:215-231. 1905 . STEPHENS, E. L., A preliminary note on the ‘embryo sac of certain Penaca- ceae. Annals ae Botany 22:3209. . Warp, H. Marswatt, On the ae sac and aor of Gymnadenia conopsea. Quart. Jour. Micr. Sci. 20:1-18. pls. 1~ I . Worrr, J. J., Cytological studies in Nemalion. ak of Botany 18:608. 1904. ee Yamanoucat, S., The life-history of Polysiphonia violacea. Bot. GAZE 42:401-449. pls. 19-28. 1906. b , Apogamy in Nephrodium. Bor. Gazerre 45:289-318- Pls. 9 1° rs > Pes >» eee i. ee eon 2 CN EO Meee ae pe on en VES THE INFLUENCE OF TRACTION ON THE FORMA-— TION OF MECHANICAL TISSUE IN STEMS: Joun S. BoRDNER Introduction The following investigation was directed to a further knowledge of the influence of traction in the direction of the longitudinal axis on the formation of mechanical tissue in the stems of plants. Petioles, tendrils, and roots were not investigated, because the wo k of HEGLER (9), Batt (1), and Hrpparp (11) was primarily on stems, and it was my purpose to add further and more detailed experimental evidence to the work done by these investigators. This research was carried on in the Botanical Labo atory of the University of Michigan. It was under the direction of Prof. F. C. EWCOMBE, to whom I am indebted for encouragement and helpful Suggestions. I wish, also, to express my appreciation of the interest manifested in my work by the other members of the staff in the botani- cal department. Historical I. STEMS: INFLUENCE OF TRACTION BARANETSKY (2) observed that a stem of Gesneria tubiflora Weighted with 308" made less growth than one remaining free. ScHOLTz (26) verified this observation of BARANETSKY, and found that stems when subjected to traction first grew more slowly and later more rapidly than the control plants. This he att ibuted to a change in the physical condition of the cell resulting from the educed ydrostatic pressure. He furnished no experimental evidence to support his theory. HEGLER (9) produced the first experimental evidence to show that plants respond to tension by an increased formation of mechanical tissue. ‘This supported the theory which Was generally adhered to by plant physiologists previous to that time; Viz., that a plant reacts toa gradually increasing strain by an increased ___Contribution No. 111 from the Botanical Department of the University of Michigan. E351] ! [Botanical Gazette, vol. 48 252 BOTANICAL GAZETTE [OCTOBER development of its mechanical tissue. In reporting the work of HEGLER, PFEFFER (21) says that a seedling of Helianthus annuus, whose original breaking strength was 160%", had a breaking strength of 250%" after two days under the pull of 150%". No breaking strength is given for a control. A petiole of Helleborus niger which withstood a weight of only 400%", PFEFFER reports to have held a weight of 3.5** after 5 days, during which time it had been weighted with a gradually increasing load, while similar petioles under normal conditions gained but little in strength. Changes are also reported in the anatomical structure: (1) an increase in the nimber of cells of the collenchyma, (2) an increased thickness of the walls of the collenchyma, sclerenchyma, and bast, and (3) the production of entirely new tissues. It is unfortunate that a full account of HEGLER’S methods and work was not published. HEGLER (10) showed that the phenomenon observed by BARANET” SKY and SCHOLTz was not purely physical, but that a physiological change took place within the cell, due to stimulation coming from the tension. As evidence, he demonstrated that when plants were dep~ived of oxygen or when they were under the influence of chloro- form, there was no response. He also found that the plants under tension were more turgid than controls, instead of less as ScHOLTZ had claimed. RICHTER (25) concluded that when the stems of Chara were subjected to a longitudinal pull, there was an increase in strength. BaLw’s criticism of RICHTER’s work is well taken. He says: “Di Resultate RicHTER’s sind etwas zweifelhaft; da er keinen Vergleich zwischen belasteten Chara Pflanzen und unbelasteten von demselben Alter und derselben Grosse gegeben hat.” ss Kuster (15) found no response, and showed that in the ie of Helleborus niger the new elements, which HEGLER (91) a were produced in response to tension, were there before tension? was applied. PFEFFER (22, p. 148) also found no response in the pro duction of mechanical tissue in plants subjected to tension. VO6CHTING (27) investigated the influence of tension on sunfl - and cabbages that had been prevented from flowering by se A decapitation. He found that no new tissue was formed, and that » increase in mechanical tissue occurred as a result of tension. owers Igo09] BORDN ER—INFLUENCE OF TRACTION ON STEMS 253 WIDERSHEIM (29) experimented with pendant branches of Fraxi- nus, Fagus, Caragana, Sorbus, Ulmus, and Corylus. He fastened weights directly to these branches and continued the experiment through most of the growing season. Only in the case of Co-ylus was there any response; viz., an increase in the number of bast fibers. BALL (1) experimented with Helianthus annuus, Phaseolus multi- florus, Lupinus albus, Helleborus niger, Ricinus communis, two species of Cyperus, and Mirabilis jalapa. His conclusion was that these plants do not respond to tension by an increase of their breaking strength or by the production of mechanical tissue. Hrpparp (12) found an increase of mechanical tissue in the stem of Vinca major when the same was subjected to longitudinal pull. He failed to find any response in the stems of Helianthus annuus, Ricinus communis, Brassica oleracea, and Phaseolus multiflorus. Hrsparp did not determine the breaking strength of his stems. 2. STEMS: THE INFLUENCE OF COMPRESSION; ALSO COMPRESSION AND PULL COMBINED Knicut (14) tied a young tree in such a manner that it was swayed only in the plane of the prevailing wind. After the lapse of one growing season, the diameter in this plane was found to be greater than the diameter at right angles to the same. HIBparp (1 1) found that compression caused a small increase of mechanical tissue in the stems of F uchsia, Vinca, and Helianthus, while Coleus gave no response. 3. ROOTS: RESPONSE TO TENSION Hipparp (1 I) says: “ Pull in the direction of the longitudinal axis of the plant called forth a small increase of mechanical tissue in the Main and lateral roots of Helianthus annuus and Ricinus communis.” 4. TENDRILS AND PETIOLES _Darwin (4; Gray 8, p. 176) says that in the grape-vine, Virginia creeper, etc., attached tendrils thicken and harden, gaining wonderfully in strength and durability, while those which remain “nattached soon shrink up or wither and fall off. _ Mitier (18) found that contact produced earlier and greater lignification of the sclerenchyma, even in the free portion of the ten- 254 BOTANICAL GAZETTE [OCTOBER drils of the Cucurbitaceae; but he did not consider tension as a probable factor along with contact. , ; Worcitzky (30) reports that tendrils of Passiflora quadrangularis which had grasped a support broke at 600%", while the controls broke at 350%". With tendrils of Cucurbitaceae, the uncoiling resistance was thirteen times as great in those which had grasped a support. There was also a marked anatomical change; viz., a lignification of the pith parenchyma, which he assigned to no cause. Von DerscHau (28) found that a gradually increasing pull on certain twining petioles raised their breaking strength and caused an increased development of mechanical tissue. He found a nu- merical increase in almost all kinds of cells. The petioles of Solanum jasminoides showed the least response. ; NEWCOMBE (19, p. 446) says, in speaking of the reaction of tendrils to contact: “The first strengthening tissue is here laid down as 4 Tesponse to contact; its increase is the regulatory response of the plant to the strain that it feels.’ See MacDoveat (17, pp. 377, 378) believes that contact stimuli oe not transmitted beyond 2 or 3™™. Since the thickening of the wee always takes place after contact, the natural conclusion would be tha this thickening of the tendril is due to the traction exerted by the weight of the stem supported by it. ee fe PEIRCE also (20, p. 241) believes that the strengthening © free basal portion is not due to contact. iin FITTING (6, p. 476) has demonstrated that contact stimuli ee transmitted to the basal portion of the tendril, and that therefore . effect of contact stimuli on the basal portion of tendrils cannot . excluded. 5. CORRELATION The factor of correlation has been investigated by eget workers. Since self-regulatory development may imply 4 " of degree of correlation, it seems desirable that at least a brief review the work on correlation should be given. : cture Laporte (16) found decided differences in the anatomical =~ of the floral axis compared with the rest of the plant: (1) 22 (3) 8 of bast, (2) a decided modification of the main bundles, and (3 decrease of pith. LE ee ee ee ee Ig09] BORDNER—INFLUENCE OF TRACTION ON STEMS 255 KLEIN (13) found the bundles more centrally located in the fruit stalk than in the petiole. He attributed this arrangement to the necessity for a greater mechanical strength, as well as for a more abundant supply of building material. DENNERT (5) compared the anatomical structure of the fruit stalk before and after the ripening of the fruit. He found an increase in the development of mechanical tissue. There was an increased amount of xylem anda greater thickness of the walls of the wood fibers. REICHE (24) investigated the transformation from flower to fruit stalk in many additional plants. His conclusions agree with those of the earlier investigators. PIETERS (23) showed that one-year-old fruit-bearing shoots of the apple and the pear had a smaller xylem cylinder in proportion to their diameters than the vegetative shoots of same age. They were well supplied with supplementary mechanical tissue, however, which was distributed at those points where it was most needed. In the case of the peach and the plum, the woody cylinder of the fruit-bear- ing shoot was larger than in the vegetative shoot. There was an abundance of well-lignified sclerenchyma and hard bast in the fruit- bearing shoots of the apple and pear, while in the vegetative shoots these tissues appeared only sparingly, if at all. GOEBEL (7, p. 206) writes: “Careful research demonstrates the existence of reciprocity between parts of the plant body... - . The size and construction of one organ are frequently determined by those of another.” : ; BoopLe (3) states that the walls of the sieve tubes and companion cells in Helianthus annuus become lignified as a result of strain. He also found a slight lignification of the parenchymatous 7 of the pericycle and medullary rays, thus uniting the primary sclerenchyma strands into a more definite mechanical system attached ‘o the strong xylem by the medullary rays. He says: “This must Sive greater rigidity, which no doubt is required by the heavy fruiting ‘apitula borne by the plants.” KELLER (12) reached conclusions directly opposed to those teached by Boopte. He showed that a strong or light pull in the direction of the longitudinal axis of orthotropic flower stalks exerted 256 BOTANICAL GAZETTE [OCTOBER no influence on the development of mechanical tissue. The dis- placement of orthotropic flower shoots to a plagiotropic position, he claimed, caused a certain anatomical change. This he attributed to the change in position and not to tension. His conclusion does not agree with those of other investigators, viz., that mechanical development of the fruit stalk goes hand in hand with the develop- ment of the fruit. : Methods In both greenhouse and field culture a much larger number of plants were grown than were used in each experiment. At the begin- ning of each experiment the strongest plants and those most nearly equal in size were selected, and the others were removed. This was done to reduce the chances, as far as possible, of individual variation. In the greenhouse cultures, the pots with the plants were placed in a row. The plants were then measured and every other one was taken as a control. At the close of the experiment, an average Was taken of all the data on the control, and also the experimental plants in each series. This was the method used by Scuortz. By pre liminary experiments, the writer was convinced that it was by far the most satisfactory, on account of individual variations in plants which make it very difficult to select any one plant that will be a fair control throughout the experiment for any one experimental plant. The methods of Batt and Hreparp for applying tension by pull in the direction of the longitudinal axis of the stem were followed. The writer was soon convinced, however, that for plants as large as those used in his experiments, the leather noose used by BALL # a tension fastening was not needed. Heavy cotton flannel and ordi- nary cotton cord, therefore, were used for this purpose in all these experiments. A strip of heavy cotton flannel 2.5°™ wide was wrapped at least twice around the stem. Over this, two cords were P@5* from opposite sides and back again. Each cord, thus passing twice around the stem, was drawn tight enough to keep the fastening from slipping. The ends of each cord were then tied to a second. were united into one strand some distance above the fastening. : av double cord was passed over a light running pulley, supported direc above the plant, and a weight was attached to its free end. At 1909] BORDNER—INFLUENCE OF TRACTION ON STEMS 257 strip of wood or bamboo about 1oc™ long was placed crosswise between the cords coming up on opposite sides of the stem,'to keep them from injuring the young leaves and growing tip of the stem. In the field cultures, exactly the same methods were followed, except that the seeds were planted in rows. The inferior seedlings were removed, and only the stronger ones were left for experimental use. In most cases the heavy clay loam was sufficiently firm to keep the plants from being pulled up by the tension. In the few cases when the soil was not firm enough, heavy flat weights were used to hold it in place. METHODS IN FINAL DETERMINATIONS Method 1.—In all but two experiments the stems were tested by direct pull along their longitudinal axes to determine whether they had responded in a self-regulatory manner to traction by increasing their breaking strength. Preliminary experiments convinced the writer that the method of obtaining the breaking strength used by BALL was not satisfactory, _ since too many of the experimental plants broke at or just below the tension fastening. Larger plants therefore were used. These were broken at some distance below the tension fastening, thus elimi- nating the unquestionably weakening effect coming from the pressure of a tension fastening on the young and tender stem. For this purpose, a strong wooden frame was constructed, about t20°™ long and soc™ high. Through the middle of the frame ran a shelf parallel with top and bottom. On this shelf rested the plant, blocks, and spring balance used in determining the tensile strength. To Stasp the ends of the stem, 4 blocks of wood were selected, each ing 5°™ thick, ro°™ wide, and 20° long. These blocks were laid together in pairs, one block above its mate, and grooves considerably larger than the stems were cut in the contact faces of each pair to Téceive the plant stem. _ During the preliminary experiments, the stems, except in the por- ton to be tested, were wrapped in moist cotton and then imbedded ‘a damp mixture of sand and Portland cement. This mixture "as placed in the groove of the lower half of the pair of blocks. The stem was then placed in position and more concrete was piled on top. 258 BOTANICAL GAZETTE [OCTOBER This was pressed down and around the stem by tightening the bolts which were used to draw the two blocks together. This method was satisfactory. It was soon found, however, that the stem could be held sufficiently firm by substituting moist cotton for the mixture of sand and Portland cement. Moist cotton, therefore, was used in all the experiments as packing to fasten the stem in the blocks. When the stems were fastened in the blocks, one pair of blocks was hooked to the spring balance, and the other pair was secured to one end of the wooden frame. The spring balance was hooked in turn to an iron rod passing through the opposite upright of the wooden frame. On the end of this rod, protruding beyond the frame, was a large tail-nut. By turning this tail-nut with the hand, tension was brought on the spring balance, and through the balance on the plant stem. The breaking strength was read from the face of the spring balance. : After the stems were broken they were preserved either in 50 per cent. alcohol, or short sections were cut from just below the breaking point in the stems, and these were killed and fixed in 1 per cent. chrom- acetic acid, thoroughly washed, dehydrated in alcohol, and kept for future study. The following methods were used in making microscopic examina- tions and measurements of the xylem and hard bast in the stems. 2 Method 2.—Measurements of the thickness of cell walls in sae free-hand sections, and also in some cases of microtome sections, were made by using an ocular micrometer. The results record are in each case an average of eight measurements taken in as many distinct areas of the cross-section. oa Method 3.—The total xylem and hard bast areas were meast : in some of the experiments by projecting a cross-section of the upon a bristol-board screen, and measuring the areas with a po planimeter. . fe Method 4.—Camera lucida drawings of the total xylem an i bast areas and also of the hard bast elements were made upon oe ardized bristol-board. The drawings were very carefuly cut ‘ with a sharp and pointed scalpel, and then weighed on @ ir ~ balance. The number of hard bast elements were also count ae fastening the drawings of the hard bast elements over sheets of y Le Ay Rae een ea ee Caudle aes vail soak J GS ticks aA fhe r909] BORDNER—INFLUENCE OF TRACTION ON STEMS 259 paper and checking off each element by marking through the lumen on the yellow paper underneath. Method 5.—The hard bast elements were drawn by means of a camera lucida and then counted to determine whether an increase had resulted in response to the pull. Method 6.—Radial and tangential microtome sections of acid- fixed material were made to determine whether any fibrous paren- chyma existed directly around the hard bast areas. This method was used only on control stems of Helianthus annuus. It was the purpose to determine whether the elements which produced the increased number of bast fibers were present before the tension was applied and therefore only developed, or whether they were formed de novo in response to tension. The plants investigated were Helianthus annuus, Phaseolus vul- garis, Ricinus communis, Sinapis alba, Vicia Faba, Lupinus albus, Rubus occidentalis, and Vinca major. Experiments Experiment 1. Helianthus annuus, greenhouse culture.—Ten vigorous plants were selected from a number of seedlings grown in pots 20°" in diameter. The experiment began November 21, 1906, when they were mostly ro to rs°™ in height, and ended 29 days later. The tension fastening was placed on the experimental plants just below the second pair of leaves. The controls were not supported. The pull applied to the experimental plants was gradually increased from 25%™ at the start to 300" on December 14, 1906. The slow growth of these plants may be due to the fact that during the entire experi- mental period there were only a few sunny days, and also to the short- hess of the day at this season of the year. _ Table I gives all the data from this experiment, except the follow- ing: By method 6, fibrous parenchyma was found in the control stems as a transitional form between the thick-walled hard bast fibers and the short-celled parenchymatous tissue. These longitudinal sections vere taken from just above the cotyledons. The increased number of bast fibers in the experimental plants, therefore, may be accounted lor as the result of the response of these fibrous cells to tension, which thus develop into hard bast fibers. ee Hace 260 BOTANICAL GAZETTE [OCTOBER The actual area of the cell walls of the hard bast elements and their number was found by method 4, and the total xylem area by method 3. TABLE I.—Helianthus annuus ae A NOVEMBER NovEMBER DECEMBER DECEMBER A |82h [ea] so 21 28 14 20 im at aes Bet. ee No. or —| 25 |g82 188) =x PLANT G22 seb Zi we z¢ Height| Diam.) Height | Diam.| Height | Diam.|Height| Diam.| 224 |3583/ 0%) #2 in in in in in in in in | BES |qons] oa] Fe cm. mm. | cm. mm. | 4 ‘) ZA | we Exp. 8 ee 19. | 4. | 29. | 4. | 50.4] 4. | 59.2] 4.2 | 7711] 6.837) O91 ce Gr 15600) 9.24 3g. ER dae Be 4.1 | 41.6] 4.2 | 5443] 7-014} 811) ©. eG ks 10.6 | 3-5 | 19. | 3.5 | 37-8 | 3.6 | 44.7] 3.5 | 5216] 6.430] 840 25 4...+.|/11.8 | 3.1 | 20.7 | 3.2 | 35.3 | 3.6 | 44.1] 3.9 | 4626] 5.488) 682) 5. ere Q. 2. 20.2 | 2, S625 53. 44.1| 3.2 5443) 5-666 ds Baeall Total |63.5 [15.8 |107.9 (15.9 |194.0 |18.3 |233.7|/19.0 287.49|31 -435|3005|33-5_ Av....|12.7 | 3.16) 21.58] 3.18] 38.8 | 3.66/46.74 3-8 |5749.8| 6.287) 721 ot Control 6.6 ere 15-2 | 3. | 22.7 | 3. | 42.8 | 4.1 | 52.9] 4.3} 5352] 5-145 39 3 Pe: Joe ee ee yee oa eee oe a eee 3039| 6.420 ; a Toss 11.3] 2.5 | ¥9. -| 3: | 34. | 3.4.| 41.6] 3.5. | 3729] 5-374] O57 7 Bee, Ir.3 | 3-2 | 18.3 | 3.2 | 34. | 3.2 | 39. | 3-5 | 2494] 5-498 or e Sao Q- | 2.2 | 12.1 | 2.2 | 23.3 | 3.2 | 30. | 3.4 | 3629] 4-679] 950) 3 Total |58.6 |14.4 | 89.7 [14.9 |168.1 17.7 |206.3/18.5 | 18233 27 .114)324823-8 ———- ; 6 Av 11.72) 2.88) 17.94) 2.98] 33.62] 3.54|41.26| 3.7 3647] 5.423] O48] 47 The percentages of increase in the experimental plants over the controls are the following: breaking strength 57.6 per cent.; cross section of walls of hard bast 16 per cent.; number of hard bast ele- ments 12.5 per cent.; and xylem area 4o per cent. TABLE Il.—Helianthus annuus paver an ay i Dis- reak Height] Di ee No. of eats ad_| above rst pait | Oren yistrength plant Height in cm. pair of ror nee below ad in kg a ae ree aU uly June | June | June | June June | June | July | July | June | July od . Exp. 21 -| 22 4 26 28 30 I I 21 < ax [16.535 Av..... 7-5 | 8.6 |12.6 |16.3 19.4 {23.8 |26.6 |10.4 | 4-1 7-26) 3- 5 Con 13-799 AX ae 7-03) 8.2 |11.3 |14.3 17.3 at.5 |24.3 | 9.2 | 4.1 | 7-43 3-7? pees eS Ye 1909] = BORDNER—INFLUENCE OF TRACTION ON STEMS 261 Experiment 2. Helianthus annuus, field culture. — After the inferior plants had been removed, those used in this experiment stood 15 to 20°™ apart in the row. Every other plant was used as a control. The tension fastening was placed just below the second pair of leaves on the experimental plants. The control plants were left free. The experiment began June 21, 1907, and ended ten days later. A tension of 250™ was applied to the experimental plants at the beginning of the experiment. This was increased to 750%™ the following day and to 19008™ on June 25. Table II gives an average of the measurements and the breaking Strength of these plants. The average increase in breaking strength for the experimental plants over the controls was 2736%™ or 19.6 per cent. The height measurements in this experiment confirm the work of ScHoitz and HEGLER (’93), showing a lessening of growth during the first 24 hours, followed by an increased growth for the next four ays. TABLE III.—Helianthus annuus Dis Diam. just . Just, tance | Break- No. of : Height to 4th above rst pair above 2d pair |of break} ing : Height in) eam, i f leaves above _|strength — pair of leeves, | of pes eee ee ae in cm Nie Eee ee i ed ew ad July | July | July | July | July | July | July | July | July | July Exp. I 30 18 18 Ric) 18 fo) 3! Pd Av........] 36.07] 89.6 | 32.33] 44.6 | 9.4 | 15-95] 7-58 | 13-39] 12-3 | 69-99 Control 3 AVeos- 5, 38.01] 90.5 | 34.6 | 45.08] 9.64 | 16.03] 7-69 | 14.37) 13-9 “12 ee Ries ee as ee Experiment 3. Helianthus annuus, field culture——Much older and larger plants than those used in experiment 2 were put under ~ tension July 18, 1908. This was gradually increased from 200%" at the start to r950%™ on July 27. The experiment ended July 3o. It was the purpose in this experiment to determine whether the same tension would have the same influence on larger and older stems as On younger and less woody ones. The average increase in breaking Strength as shown in table III in response to a tension of practically T900%™ was 3.87%, while in experiment 2 the increase for a period Of Io days was 2. 74*s, The increase as a percentage of the average 262 BOTANICAL GAZETTE [OCTOBER breaking strength of the controls in this experiment, 5.8 per cent., was much less than in experiment 2, since the breaking strength was so much greater. The tension fastenings were made just below the fourth pair of leaves. Similar fastenings were made on the control plants, and from these the plants were fastened to upright supports to keep them from being swayed by the wind. Experiment 4. Sinapis alba, field culture.—These plants grew approximately 15°™ apart in the row. Every other plant was used as a control. The tension fastening was placed just below the seventh node above ground. Similar fastenings were placed on the control plants. From these fastenings, the plants were attached to strong cords, stretched one on each side of the row and parallel to it. A weight of 250%™ was attached to the experimental plants on July 16, 1907, and gradually increased to 1150%™ on July 24. The expen- ment ended two days later. The details of this experiment are giv in table IV. The average increase of the breaking strength of the experimental over the control plants was 4.8*% or 32 per cent. The anatomical structure of these stems was determined by methods 2, 3, 4, and 5. Free-hand sections were made of all the stems about 5™™ below the point where they broke. These sections were stained in anilin safranin and mounted in glycerin. All the slides were then taken by a second party who labeled them with a secret label. The measurements given in table IV were then made, after which the second party gave me the key to the labels. The measure ments of the experimental plants were now separated from those of the controls. An average of each set shows a decrease of 10 per cent. in the total xylem area and an increase in the thickness of the xylem cell walls of 5 percent. The increase in hard bast in 5 stems which were selected wholly by chance was 52 per cent. The increase © hard bast elements in the same stems was 38 per cent. The total xylem area for the five stems in which the hard bast determinations were made was also measured by method 4 < results that agreed within less than one-half of 1 per cent with the measurements made by method 3. The hard bast in the controls was lignified in all but a few ste" where it was only partly lignified. Stem 18 showed the least Diam. abo ground in mm. seseee weseees ene oe oe eevee ee Ceereen see eee ees eee eerene a te eveee eee eae 49.791 July 16 26 6.85 ‘ 5.1 Oe 5. 6.07 4-65) 7.5 5-2 7:15 5:95 | 8.8 7-2 9-35 7-4 9-9 7-45 9-33 6.05 7.32 5.85 8.3 6.55 8.65 5:75 | 7-6§ 6.45 8.1 5-4 5:77 47. 6.75 4.6 5.2 5.35 ors 4.1 YP 109.3 | 145.99 5:75 | 7-68 8.158 {6061 Xylem area in sq. cm. X10 SHALS NO NOILIVAL O JINXATANI—NA NANO fgz TABLETIV.—Sinapis alba (continued) ne g fs ga as e : m4 Diam. just scat iD z 2 Ge 3 = No, of plant Height in cm. tc ei a4 e ve BEGs - 3 26 » : eae os a mmm” = | GHEE | Gey | Sosa | See | fe | peg QO io} 6 ae > ES A Fa s 4 ee Sapa : Contedt Jit July oe auy ord July ae July July July as July RRS SE a Aang 23.4 55-5 20. 24. 5.10 725 T5 Dh IE a eae y tore Po ess) MO ton, 1, 26.3 63. 20.5 aa'.5 6.10 8.do ie EUSP 0 te sada | Ia aa 11.43 | 3.062 AE RCN EA RR ape 172 50. T4025) 089.5 4.15 5.75 ses LES 4 Re Be CaS ae Ap 81 2.562 Be eae clas 6's 20.3 63. I5.4 19.5 5.60 7.708 eae TAEDA ss ss oe P2535 4(:) 087 Pees 9 no eles + 18.8 58. 14.5 19.5 5-35 8.90 bre. 19.94 | 7-075 542 I2.70°|° 3;062 Me aces sys 26. 60. 22.5 34. 8.00 | 10.62] 19. ore is ne ae 19.05 | 3.000 SE HA a2. 64. 7.5 21.5 7.20 9-35 TO; Ir.79 | 4.714 365 16.51 2.562 Pe Es 24.4 63. 19.5 22’. 6.20 5.73 ae ED meee ete eset 8 vs 7.:625| 3.000 Me Statin eon Was 21.7 66. 16.3 22. 7.00 8.63 5 DOOM ale ate ss 10.80 | 3.062 Be ee es us 26.3 66. 22.2 3.5 chr as I0.30.;| ‘Io rer iie fie || Pee: | area | 19.69 2.437 PE ln OL A NaS Bie 21.9 58. 18.0 20. 5-15 6.10 8 oR Wa fee eta fics sc 3 6.35°1° 3-437 11 AGS ARI Sse ree 28.5 70; 28.3 34-5 6.30 LOO A. 7 19.03 || ° 5.700 510 S2a50| 2.e75 ae ays eis» 6 28.7 62 aia 24. 5.60 025 7 TT AG a rome ten swiss «ts :35 | 4.062 PR ees 25.8 66. 21.5 28. 5.80 Popa a8 MODAL ene a liaise. 3s BXs43-) 9.378 EE a7 79. 275 24. 5.00 6.55 8 12.68 | 5.040 491 6.67 | 3.125 eee ye Cav we ois 24.5 57. 20.5 24. 6.10 7.80 yi payee | sa el ee ae II.43 2.500 Lk OSE Sas ee S136 bale 25.0 a7 5-20 O.00|- 12 Bo OMR eee Hedfi. sys «3 6.03 | 3.062 Bee eae is. 26.3 5I. 21.8 23. 4.40 Bsouh 13 Si Saal TSO 395 8.89 | 2.500 ee sis ba 26.5 6r. BS 24. 5-40 ToAS 8 FASB OM ne con sck ole wae 13.07 3.500 «Reo a age aaa 19.5 o2. 16.3 20. 4.80 0.104) Io TS ROWae Math ses os 135397 2.561 396.9 | 486.5 | 115.60 156.92 | 225. | 298.60 | 26.697} 2305 868 24.4 61.8 19.84 | 24.32 5.78 | 7.85 | II.25 14.93 | 5-339| tgz ALLAZVI TVIIN VLOG _ Igog] BORDNER—INFLUENCE OF TRACTION ON STEMS 265 cation among the controls. Stems 5, 7, 12, and 1 5 were all well lignified. The hard bast in approximately ro per cent. of the experi- mental stems was completely lignified. In the five stems for which the hard bast determinations were made, only a few elements were lignified in 8 and g, while in 16 lignification of the hard bast was almost complete. Experiment 5. Phaseolus vulgaris, greenhouse culture.—The plants for this experiment were grown and selected in a like manner to those for experiment 1. The tension fastening was placed just below the second pair of leaves. The experiment began October 21 and ended November 8, 1907. The weight attached to the experi- mental plants, 400%™ at the beginning, was increased to g50%™ after five days, and to 11 50%" November 5. The controls were left unsupported. TABLE V.—Phaseolus vulgaris | a 4 : | Height to Diam. just iam. ge er 2 : z E No, of Height in 2d pair of above above coty- =; Se |& 5 M, ~ g2 Plant cm. leaves in ground in ledons in os | Seale a Bax cm, mm. mm. ga | Suz] FX) 38 AY a) rs) 4 Oct. | Nov. | Oct. | Nov. | Oct. | Nov. | Oct. | Nov. | Nov. | Nov. | Nov. Br te Exp. 21 8 21 aI 2r 8 8 8 4 (5 13.5 |25-. fEQ.E |a4ct [ds gala, Bap Sed fe wee 6.795|88.08) 6.59 Control BV nas 13.3 {20.8 |12.0 |12.8 | 4.16] 4.53] 2.98] 3.34|-.--- 5.098|76.57| 5-42 The average measurements and results of this experiment are given in table V. The breaking strength shows an increase in the €xperimental plants over the controls of 1.7**, or 33 percent. Sec- tions taken just below the breaks showed an increase of 15 per cent. in the area of hard bast, and 22 per cent. in the area of the xylem. hese measurements were made by method 3. The hard bast and xylem were equally lignified in experimental and control plants. Experiment 6. Phaseolus vulgaris, greenhouse culture.—These Plants, when the experiment was started, were ten days older than those used in experiment 5. The experiment began December 7, ‘997, and ended January 7, 1908, at which date most of the blossoms had already fallen from the plants and the leaves were beginning lose their chlorophyll. A weight of 250%™ attached to the experi- 266 BOTANICAL GAZETTE [OCTOBER mental plants at the beginning of the experiment was gradually increased to goo#™ on December 20. It was the purpose of this experiment to determine, by prolonging the experimental period and growing the plants to maturity, whether the response in the earlier and actively growing period was continued to the end of the vegetative period. For this reason no additional weights were added after December 20. Both experimental and control plants broke with almost the same weight. The experimental plants were much more brittle and in most cases broke with a smooth, clear break, while the controls showed more of the elasticity and toughness which was characteristic of the stems in experiment 5. Experiment 7. Phaseolus vulgaris, greenhouse culture.—After finding that response to tension, if any had occurred in experiment 6, was vitiated by permitting the plants to grow to maturity, experiment 5 was repeated, beginning March 5 and ending fourteen days later. The weights used, 2008™ at the beginning, were increased to 4508" March g and to 7oo®™ four days later. The experimental plants showed an average increase in breaking strength of 3.32*¢, or 42.5 per cent. The number of hard bast elements was determined by method 5. The experimental plants showed an average increase of 167, Or 14.9 percent. The results of this experiment, therefore, agree with those of experiment 5. The tension fastening in this and also in experl- ment 6 was made at the same place as in experiment 5. Experiment 8. Vinca major, greenhouse culture.—In selecting plants for this experiment those were taken which had young and actively growing shoots, uniform in general appearance and length. No measurements were taken at the beginning of the experiment, December 1, 1906. The experimental shoots were put under a tension of 50®™ at the beginning, which was gradually increased to 300°" 0? December 21. The control plants were fastened to an upright suP- port, but were not under tension. tee The breaking strength was tested in the internode just below the fastening which was in an active growing condition in each plant when the experiment was started. The average shows an increase the experimental plants of 649%™, or 15.2 per cent. Experiment 9. Vinca major, greenhouse culture.—It was - purpose ofthis experiment to determine whether internodes which ~ . pingip' te Mens Ue oT Si Wee SU Ss ey tr ee kere : 4 ‘ 4 1909] BORDNER—INFLUENCE OF TRACTION ON STEMS 267 were no longer elongating would respond to tension by increasing their breaking strength. For this reason, shoots older and larger than those in experiment 8 were used. The controls were supported as in experiment 8. A weight of 200%™ attached to the experimental shoots on November 15, 1907, was increased to 400%™ on December 14. The experiment ended January 8, 1908. The third instead of the last internode below the tension fastening was tested for its breaking strength. No elongation and in many cases no growth in diameter took place in this internode. An average of the breaking strengths shows no response to tension for an internode which is no longer actively growing. TABLE VI.—Vinca major Recorp A 2 SSE ac EE, —=- aioe mee ; | we laeel| So = / g g | par 32 |eti 2 |g | £2 | 2 | | Height to | nam just| ~e |oe8] # $8 Pe oe n + | * - Just Mite: Ss o= ey 2a No. of Height in ore et below 33 os 2 Ae 5 x) = 23 5 EE Plant | cm, Siepouskd fastening | fo | 88'S) Ga laee| #7 | eoel| wo fastening rsh we | eo) 2 ese} ae | EB Ca : in cm. C8 |Smu/ 3 os 22 we . 3 | in em, sa |2ee| Bs |2 a a 258 64 | Fa a = o 2 a A Bel | | | Be BPSATS rai! Jan. | Jan. | Jan. | Jan. | Jan. | Jan. Jan. Pat 9 25 ° 25 9 25 | 25 } AY. . “|29- |41.4/25.6/27.3 2.11|2.22| c ereaet 8.25 ee ee bipage. pee e eee: Control | | | Vi, aa \44- /28 4/29 6/2 og}2 70) : 8.75 pee. | peers | Par er ke ie er Se a Be A eg shee | ey ee Be Peeirees Were: ae Vinee SAR LT Ps. a ee eee ea Recorp B l Sopsees WED a I Mar. | | Mar. Mar | | Mar. | Mar.| Mar. | Mar. | Mar. _ Exp. rest et byes es 2 fe BY: . -|29.2195. 2 del bag sad act dese 15 | 8.22] 5.77] -2777| 7-42 | 127 Control | | } | Ay. + |28.6)62 26.|28.5 as 2.321 eo 52:3 6-97 509) ae 6.56 | 1297 | | i Berens Experiment 10. Vinca major, greenhouse culture.—This experi- ment was in large measure a repetition of experiment 8. -Tension fastenings were madé on all the shoots. Just enough weight was attached to the control shoots to hold them erect. The experiment began January 9, 1908, with a weight of 250®™ attached to the experi- Mental plants. This was increased to 450%™ eight days later, and to gooe™ January 25. The internode to which the tension fastening was attached was in each case actively elongating at the beginning of the 268 BOTANICAL GAZETTE [OCTOBER experiment. One-half of the shoots were removed and tested January 25,1. ¢., after 16 days and subjection to a maximum tension of 4508". Table VI, record A, gives an average of the results for this part of the experiment. The average breaking strength is slightly increased in the experimental shoots. The remaining shoots were tested March 2, 1908. An average of breaking strengths as given in table VI, record B, shows an increase in favor of the experimental shoots of 1.25" or 18 percent. A study of the anatomical structure of these stems was made by methods 2, 4, and 5. These determinations show an increase of 30 per cent. in the entire xylem area, an increase in xylem wall thickness of 13 per ‘ cent., and the same increase in the thickness of the walls of the hard bast fibers. A count of the hard bast fibers showed no increase in the number of these elements. Experiment 11. Ricinus communis, field culture—The method in this experiment was the same as in experiment 2. The tension fas- tening was placed just below the second pair of leaves. The control plants were not supported. The experiment began July 20 and ended August 1. A tension of 300%™ at the beginning was gradually raised to 2350%™ two days before the experiment ended. TABLE VII.—Ricinus communis < lz i e ez s 2 @ Fo n : E 4 o BS§ = oe Height to Chie at Diam. just § cay eX 2s 2d pair of wh ah above 1st 2 on 2. | Bay . base in : bo oes ove leaves in panel pair of leaves| & Zeck 5 2 =e E cm. in mm. tas 6 - og | ks PE | Bae) Be | z a IR * : July | Aug. | July | Aug. | July | Aug. | Aug. | Aug. | Aug. gens 20 I 20 I 20 ‘ I I ee 038 16.25 Ey aS a § 8.18)}12.18)10.66 13.01/43 86/10. 24 21S 16.4 |19.6 | 8.44/11.41| 9.95|12.56|41.22/10.4 25-99|2-929 eee See prs teat | The average results, given in table VII, show 43.86** as the aver age breaking strength for the experimental plants and 41.22%8 for the controls, or 6.4 per cent. The increase is slightly greater than the final weight which was attached to the experimental plants. 1° average xylem wall thickness and total xylem area, as determined by methods 2 and 3, show an increase respectively of o. 1# and 4 per cent. or ee ee See > er oe a: “ . ae ey Nea a hata > Se Oy Mee RPT ee pe Emer NT ome ey et tie ten RE Pt RR ae a ee ee ee 1909] BORDNER—INFLUENCE OF TRACTION ON STEMS 269 The bast fibers were not well defined; many of them only very slightly thickened. It was therefore impossible to make an accurate count of their number. Experiment 12.. Rubus occidentalis, field culture—On June 25, 1907, ten young stems were selected which in general appearance were equally vigorous. Tension fastenings were placed on five of these approximately 35°™ from the ground. The controls were left free. A weight of 2.25** at the beginning was increased to 4.5‘¢ on July 6, and to o** 24 days later. The experiment ended September 3o. The decrease in height in the experimental plants was very marked. Growth in diameter was also less. The total bast and xylem areas were determined by method 3, giving an average increase in bast of 13.6 percent. over the controls, buta decrease in xylem of 30 percent. This decrease may be partly attributed to the reduced growth in diam- eter of the experimental plants. Experiment 13. Vicia Faba, greenhouse culture.—The experi- mental plants were put under tension on October 24, 1907, the fasten- ing being placed just below the fifth node. Since Vicia Faba grows very rapidly, it was thought possible that it might respond to a stronger tension than that applied to stems of other species of like cross-section andage. A weight of 450%, therefore, was applied at the beginning, increased to goo®™ two days later, and to 13008" on November 6. Since illumination is greatly reduced at this time of the year and growth is comparatively slow, this large weight caused the stem to elongate More rapidly than the control. This was accompanied by diminished gtowth in diameter. The control plants were left free, and since Vicia Faba retains its orthotropic position with great difficulty, these grew larger in diameter and less in height. When the experiment ended on November 9, the breaking strength of the experimental Plants was less than the breaking strength of the controls. Experiment 14. Vicia Faba, greenhouse culture—The results of experiment 1 3 gave cause for this experiment, in which an effort was made to eliminate or at least minimize the effect of those factors which may have obscured the response to tension in the last eApen ment, if such a response did occur. For this reason, the experment Was carried on during the season of the year when illumination was much stronger and hence the chances for growth much better, all other 270 BOTANICAL GAZETTE [OCTOBER factors affecting growth remaining unchanged. Smaller weights also were used on the experimental plants, and the control plants were sup- ported by small weights, barely sufficient to counterbalance the weight of plant, attached as the larger weights were to the experimental plants, the cords running over pulleys. The experimental and control plants were now growing under exactly the same conditions, except that the former were subject to tension of 2008™ at the beginning, increased to 450°™ on March 19, and to 700o%™ on March 23, and finally to g50*™ on March 30. The experiment ended April 6. TABLE VIII.—Vicia Faba ne) = “il = 3 BE6)¢ | 2 28 E ye cas Height to 4th | Diam. just | Diam. just |22.E) : § grb ses ot re node in above rst below 4th ee se 2 E m 5 | Pp cm. leafin mm. | node in mm. | £ AS fxm] oe =a awo| a= So | &¢g Swell) as | °2 | &¢ 7 e Sh v.a ot Es (a = A * | | Mar. | Apr. | Mar. | Apr. | Mar. | Apr. | Mar. | Apr. | Apr. | Apr Apr. | Apr Exp. 14 | 6 14 145°) 36 I 6 6 6 6 1 Gare 21.3 69.8 ES 012023 5.0: 8 40! 4.82)-6:33 8.8 |24.91 1630.3/|22 75 Control Av. :....|22.4 |66. |15.3 {18:0 | 6.01/ 8.40) 4.80 6.39 9-3 |20-59 141Q.4|2T.00 Pe RE i | j | eens Se The results are given in table VIII. The breaking strength shows an increase of 4.35** or 21 per cent. for the experimental plants over the controls. The number of hard bast fibers, determined by method 5, and the total xylem area by method 3, show an increase in the former of 14.8 per cent., and in the latter of 8.3 per cent. TAB LE IX.—Lupinus albus ees Height to Diam. oesitooe Ne: - Xylem No. of plant Height in cm. | cotviedons between gr area in | sagas and cotyledons pone | Pls Aeaii Meier SE | rae les | : | ' Mar, Mar. ! Mar. | Mar Mar. Mar. Mar. | Mar Exp. 2 Be 2 to) 2 30 3° a AV... Sarees 4-74 g.02 | 3.54 5.06 3.9% 2.91 839-4 | 9 Control ; | 7 | ‘ .800 AV. cad ccd arent ie | 3-55} 3-97 | 3-70} 2-97 155 | ae Experiment 15. Lupinus albus, greenhouse culture.—This expe™ ment began March 2 and ended March 30, the experimental plants Igog] BORDNER—INFLUENCE OF TRACTION ON STEMS 271 being subjected to a tension of 250%™ at the beginning, increased to 500%™ seven days later, and to 750%" on March 19. On account of the shortness of the stems, which made it impossible to fasten them into the apparatus firmly enough to hold a sufficient weight, the attempt to determine the breaking strength of these stems Was unsatisfactory. The reduced diameter, in that part of the stem below the cotyledons as shown in table IX, was due to a collapse of the tissue surrounding the stele. The total xylem area and number of hard bast elements, determined by methods 4 and 5, show an average increase of the former to be 14 per cent. and of the latter 11 per cent. Summary An average of the different determinations made in the foregoing experiments is given in table X. In all except experiment 9 with Vinca major and experiment 13 with Vicia Faba, the average break- ing strength in the 246 tests shows an increase in the experimental plants over the controls. This must be attributed to a response to traction along the longitudinal axis of the stem. The negative results in experiment g show that the older part of the stem, where active Srowth has ceased, does not respond by increasing its breaking strength. The lack of response in experiment 13 with Vicia Faba can be attributed to factors which vitiated the influence of tension. These conditions are fully explained in experiments 13 and 14. Experiments g and 13, therefore, may be left out of consideration. The average area of the cell wall of the hard bast elements shows an increase in the experimental plants over the controls for Helianthus dnuus and Sinapis alba. This determination was not made for the other species investigated. The average number of hard bast elements shows an increase in the experimental plants over the con- _ trols in all the species for which this determination was made, except Vinca major. Phaseolus vulgaris and Rubus occidentalis also show an increase of total bast area in the experimental plants over the con- trols. The average thickness of the hard bast fibers in Vinca major as found to be greater for the experimental stems. . In the total xylem area determinations, the only decrease was 1n Sinapis alba and Rubus occidentalis, in both of which, however, there - 242 BOTANICAL GAZETTE [OCTOBER was an increase in hard bast. The other species all responded to tension by increasing their xylem area. The average thickness of TABLE X.—SUMMARY No. of experiment Avi Aver- | Aver- |Average| ,._. |Average — i age | age thick. ick thick- | 175 of Name of plant ing ead pny beni of hard Pans ee eogth) bast | bast bast | bast Pos xylem n kg. fibers | fibers | area |cell walls cell walls lelianthus es Ls BEE a 7 § mn eae ae 6.70 5 lianthus annuus | 3 Watine asl’ Gan of sk 4570 5 felianthus annuus /16, SS eres eaectiaaits sate pore ee elianthus annuus |13., Tia wo paiae| Eee arcae Peeerand eboney (Ae Macnee poe elianthus annuus 69 SONOS 7% SEC es ee ee elianthus $106,520). si: Epi fetes peters Rene 57 Sy napis a By F7Ol Se. TR O36) sol. aves 9-39] 3- napis alb au 5-330 MEE OE aia ee. 10.51| 2.993} 20 haseolus Vitpatis 16, 9get S|. BRUogiss COORG oer haseolus vulgaris Oe, | ee ae ase NOSE oO 5 -42].-+++- Phaseolus vulgaris (eect e) Waseremte | ge Plane oly oo ae adie La eee Phaseolus vulgaris ce’ fo. (aeeperee | Reagent) Wein enti be onee abe cos Phaseolus S16. 3361. S top Co Beenie Seren wey Maar CS Ei Phaseolus vulgaris y As on pee ea es Ops Pees epee oeese bere Vinca major is or | ome ane Ee Soren eee Se nee 2 ajor gS IR cate eran eee eed Mame etry Daren ats cn ec 9c Vinca major* Lh, 2 CS Sinea ee paatieeraes peta! paren ome Vinca major* i; Rag Rn tess Sy npems Cerne P< Vinca major Bogaat os 1276|:.... 7-42 |-2777| 5-77 Vinca major GOO7Gh 5 os 7] see 6.56 |.2141| 5-09 Ricinus communis Ags HOOPS e hele ligl pe eee a ed 2759] | eres cinus communis |41.220|......|.....|.....|...... 5-99}- +--+ +} ubus occidentalis |. 0.1... 1... SOs 210 Rubus occidentalis | .....|......|..... cee Bae £i9O9) ss os Vicia Faba* PALOO SS seen] cele 3 | apa si Boccia terme acti aae ee oie Vicia Faba* BO gt a eb see eee Vicia Faba 24 OTOL 6s BOBO eee 22.75). +0 Vicia Faba 20 SOON ss 2 PAID) ste 21.00]..--+- Adenine Wibaa to PAG) iis a eee ts Q127|----+° Lupinus albus {......|.... i ee ips a ae S000}. ..++: * See experiments for explanations of negative results. ° . . . . : in xylem cells walls in Sinapis alba and Vinca major was also greater the experimental stems than the controls. % Conclusion The results of the foregoing experiments have convinced the sed conclusively that actively growing stems of the herbaceous plant investigated and of Vinca major respond to traction along their cat tudinal axes, by increasing their breaking strength; also “a ee increased development of bast or of xylem, and in most cases by Z q 4 4 = 4 af 4 = S N 1909] BORDNER—INFLUENCE OF TRACTION ON STEMS 273 increase of both these mechanical tissues. The experimental evidence for Rubus occidentalis was too limited to be conclusive. The stems were already too old and mature when the experiment was started. The writer is convinced, however, by this experiment with Rubus occidentalis, that the tension used by WIEDERSHEIM (29) on pendant woody branches was not sufficient to send a stimulus past the stimulus threshold. UNIVERSITY OF MICHIGAN LITERATURE CITED 1, BALL, O. M., Der Einfluss von Zug auf die Ausbildung von Festungsgewebe. Jahrb. Wiss. "Bot. 392305. 1904. . BARANETZKY, Die tagliche Periodizitit im Langenwachsthum der Stengel. Mém. Acad. St. Petersb. 27:2. 1879. 3. Boopre, L. A., On igaiicains of phloem in Helianthus annuus, Annals of Botany 16: xb: 1902. 4. Darwin, C., On the movements and habits of climbing plants. Jour. Linn. Soc. London g. Also reported in GRay, A., q. 2. . DenneRtT, E., Anatomische Metamorphose der Bluthenstandaxen. Bot. Heft. F anak Bot. Gart. Marburg 2: 128-217. 1887. Abstract in Bot. Jahresb. 157:647. 1887 Fittre, H., Wate Ree zur Physiologie der Ranken. Jahrb. Wiss. Bot. 39:4 GorBEL, K. Ones of plants (Eng. ed.) 1:206. 1900. » Gray, Asa, Scientific papers of Asa Gray 1:176, 1889. Hectrr, R., reported by PFEFFER, q.V ge den Einfluss des soechahiaetine Zugs auf das Wachsthum der Pflanze. Beitr. Biol. Pfl. 6:383. 1893. TI, Hipparp, R. P., The influence of tension on the formation of mechanical tissue in plants. Bort. GazETTE 43:361. 1907- 12. Kriirr, H., Ueber den Einfluss von Belastung und Lage auf die Ausbildung des Cathet in Fruchtstielen. Inaugural Dissertation, Kiel. 1904. 13. Kiem, O. , Beitrage zur Anatomie der Inflorescenzen. Inaugural Disserta- tion, Berlin. 1886. ia) ul (aaa) am 9 14. Kyicut, T. A., Phil. Trans. Roy. Soc. London 2:277. 1803. 15. Kuster, E., Beitriige zur Kenntniss der Gallenanatomie. Flora 87+173. IQ0o. 16. Lazorm, E., Sur l’anatomie des pedoncles, comparée 4 celle. oe - Compt. Rend. Acad, Sci. Paris 99:1086. 1884. Abstr. in Bot. J 12: 2273. 1884. MacDoveat, D. T., The mechanism of curvature of tendrils. Annals of Botany 10: 373, 1896. nt ral BOTANICAL GAZETTE [ocTOBER - Mtxier, Orro, Untersuchungen iiber die Ranken der Cucurbitaceen. Beitr. Biol. Pfl. 4:97. 1887. - NEwcomBE, F. C., The regulatory formation of mechanical tissue. Bor, GAZETTE 20:441. 18 . Peirce, G. J., Plant phiiticny 241. 1903. . Prerrer, W., Untersuchungen R. HEcLER’s iiber den Einfluss von Zug- kraften auf die Festigkeit und die Ausbildung mechan. Gewebe im Pflanzen. Ber. Kgl. Sachs. Gesells. Wiss. Math. -Phys. Cl. 43:638. 1891. , Pflanzenphysiologie 2:148. rgor. . Prerers, A. J., The influence of fruit-bearing on the sie of mechani- cal tissue in some fruit trees. Annals of Botany 10:511. . Retcue, K., Beitrage zur Anatomie des Inflorescenzen. ba Deutsch. Bot. Gesells. 5:310. 1887. - Ricurer, J., Ueber Reactionen der Characeen auf dussere Einflusse. Flora '78:419. 1894. - ScHoi1z, M., Ueber den Einfluss von Dehnung auf das Langenwachsthum der Pflanzen. Beitr. Biol. Pfl. 4: 2323. 1887. - V6cuTING, H., Zur experimentellen Anatomie. Nachr. Kgl. Gesells. Wiss. CER Math. -Phys. Cl. 38:278. 1902. - Von Derscuav, M., Der Einfluss von Kontakt und Zug auf “rankende Blattstiele. Togaguial Dissertation, Leipzig. 1693. . WIEDERSHEM, W., Ueber den Einfluss der Belastung auf die Ausbildung von Holz und Bastkorier bei Trauerbiumen. Jahrb. Wiss. Bot. 38:41. 19°3- - Worcrtzky, Vergleichende Anatomie der Ranken. Flora 69:79- 1887- THE MODIFIABILITY OF TRANSPIRATION IN YOUNG SEEDLINGS JosrEpH Y. BERGEN (WITH FIVE FIGURES) The writer has often noticed the fact that young seedlings (e. g., of Cucurbita and Phaseolus) grown under bell glasses wilted almost at once when exposed to the dry air of a furnace-heated or steam- heated room. Gardeners all know that plants started in cold frames must be “ hardened” by gradual exposure to the ordinary atmosphere, brought about by lifting slightly the sashes with which the cold frames are covered. It appeared worth while to investigate quantitatively the rate of transpiration of these tender seedlings, grown in an extremely moist atmosphere, and the simplest possible case for study seemed to be that of annuals, for these cannot be supposed to have inherited a tend- €ncy to develop extreme adaptations to an abnormally moist atmos- Phere during part of the brief lifetime of the individual plant. Seed- lings of the following species were grown in well-watered earth, some under glass cases with air-tight joints, and others in the free air of a furnace-heated room. Cucumis sativus Oxalis corniculata Ipomoea purpurea Phaseolus vulgaris Lupinus albus Salvia splendens Mirabilis Jalapa Sinapis alba Nicotiana “Sanderae” The temperature was on the average about the same for the covered and the uncovered plants; the former, of course, received a trifle less light than the latter. The moisture of the atmosphere about the leaves naturally differed greatly. Those in glass cases were in a _‘Rearly or often quite saturated atmosphere. Those in the free air “4 the room were in an atmosphere of which the relative humidity during the winter months ranged from 16 to 32 per cent., averaging less than 25 percent. This is drier than the average summer atmos- Phere of an oasis in the Sahara. Some plants were also grown In 4 — “73) [Botanical Gazette, vol. 48 276 BOTANICAL GAZETTE [OCTOBER greenhouse, where the relative humidity was usually not far from 60 per cent.' In general the plants grown in nearly saturated air and in dry air or in that of moderate humidity presented considerable contrasts in their development.? Those from moist air were taller, more slender, longer-leaved, less hairy (if the plant were naturally pubescent), with od én j : as 3 >hotograpnet Fic. 1.—Ipomoea plants, moist-air form and dry-air form. X4- Photograt by Rospert CAMERON. . a < 3 Re 2a VES. thinner, lighter-colored, more pliable, and more translucent a6: ee ‘ selop- In many cases the moist-air plants showed an accelerated deve af . ; ‘ : sicet 1€ ment, producing more leaves in a given time and flowering et ‘ A : : eee! ae tiv than those in drier air. Most of the exact measurements 0! rela ; nr * > . y 7 Vi yar ‘ The writer’s thanks are due to Professor GEORGE L. GOODALE of Har University for the use of space in the greenhouses of the university. 2 See WIESNER, J., Forminderungen von Pflanzen bei Cultur im Raume und im Dunkeln. Ber. Deutsch. Bot. Gesells. 9:46-531- 1891. absolut feuchte? 1909] BERGEN—TRANSPIRATION IN YOUNG SEEDLINGS 277 development were made on plants of Phaseolus. In different lots of these, the moist-air individuals were 15 to 40 per cent. taller than those grown in drier air. The leaves of the former were sometimes as much as 80 per cent. longer than those of the latter, the difference being largely in the petioles. On the other hand, the diameter of the first internode above the cotyledons was (in plants grown in the green- house) 30 per cent. greater for those outside the moist glass cases. For house-grown plants the leaf thickness was 25 to 40 per cent. greater in the dry-air plants, and for those grown in the greenhouse Fic. 2. Sinapis, entire stem and leaves, moist-air form. X4.—Fic. 3. Sinapis, upper half of stem and leaves, dry-air form. X it was 2 5 per cent. greater than for those under glass cases. The Most notable differences in growth of dry-air and moist-air individuals Were shown by Ipomoea, in which the moist-air specimens were ‘wining freely, when dry-air specimens of the same age had relatively short internodes and showed no tendency to twine (fig. 1). Mirabilis Plants in nearly saturated air, by the time the second pair of true leaves had spread apart, were three times as tall as those grown in house air and much more slender. Sinapis, on the other hand, appears depauperate when grown in nearly saturated air, as shown % gs. 2, 3. The leaves of Sinapis, and of Cucumis also, in very Moist air often show the less indented margin referred to by WIESNER.* 3 Wiesner, J., Biologie der Pflanzen 65, 66. Wien. 1902. 278 BOTANICAL GAZETTE [OCTOBER The relative translucency of moist-air leaves and dry-air leaves was approximately measured in the case of Nicotiana and of Ipomoea y blue-printing them with various terms of exposure to sunlight, until an equal degree of blueness was obtained-for the portions of paper covered by each kind of leaves.¢ The moist-air leaves of Ipomoea were found to be 3.5 times as translucent as the others, and those of Nicotiana 3 times. In the latter plant many of the first leaves grown in moist air stand nearly vertical, while those of the dry- air plants form approximate rosettes. This vertical growth of the moist-air leaves is exactly the reverse of the epinasty of the leaves of Sempervivum tectorum and Ovxalis floribunda noted by WIESNER.’ The differences in form and size between Nicotiana leaves and Ipomoea leaves grown under moist and under dry conditions are shown in jigs. 4, 5. The histology of the leaves studied did not differ nearly as much as it often does in sun plants and shade plants of the same species. In house-grown individuals of Phaseolus, leaves developed in dry air exceeded in thickness those in the glass cases by 25 to 33 per cent., the upper epidermis of the former was about 25 per cent. thicker, and the palisade layer was a little thicker. On the other hand, moist-air leaves of Sinapis were found to be a little thicker, and of Ipomoea sometimes 25 percent. thicker, than leaves of these genera grown in dry air. As might have been expected, less notable differences were found between leaves grown in air nearly saturated with moisture and those grown in the moderately moist air of the greenhouse. The behavior of moist-air leaves and dry-air leaves, on being deprived of a water supply and exposed to air at a temperature of about 21° C. and 25 per cent. relative humidity, differs greatly. Ifa shoot of each kind is cut and exposed to such air, in many cases — (Brassica, Cucumis, Ipomoea, Oxalis, Phaseolus) wilting begins in from 0.5 to 2 minutes. Even if the shoots are cut under water and — kept with the cut end always submerged, wilting is prompt and con- tinuous. Shoots of Phaseolus were cut and laid in sunshine, in ait | of humidity probably below 25 per cent., at a temperature of 23°3 C. : One shoot was from the saturated air of the glass case, the other from 4 4 This of course only measures translucency with reference to those rays which affect the blue-print paper chs q 1909] | BERGEN—TRANSPIRATION IN YOUNG SEEDLINGS 279 dry house air. Bits of the lower epidermis were peeled from the under surface of each kind of leaf at about 2-minute intervals and instantly placed in absolute alcohol to fix the stomata.’ The opera- tion was repeated on another day with fresh sets of leaves. It was found that in less than six minutes the stomata of the dry-air leaves were most of them closed to less than half their initial width, while ; Fic. 4. Nicotiana leaves; A, moist-air form; B, dry-air form. X4.—Fic. 5. Pomoea leaves; A, moist-air form; B, dry-air form. X4 those of the moist-air leaves were but little affected. In about 15 minutes most of the stomata of the dry-air leaves were tightly closed, While most of those of the moist-air leaves still remained open. _ Apparently the speedy wilting of the moist-air leaves is due to two causes, the insufficient closure of the stomata and the relatively high Permeability of the general surface of the epidermis to moisture. Wag vto™ F. E., The physiology ‘of stomata. Publ. 82, Carnegie Institution of ashington, 1908, 280 BOTANICAL GAZETTE [OCTOBER A curious kind of quick adaptation to dry conditions may some- times be noted. Young leaves of Ipomoea, grown in nearly saturated air, were found to wilt in air of less than 30 per cent. relative humidity in about two minutes, though the stem was cut off under water and kept immersed in water. After being left for some hours in a satu- rated atmosphere until the wilting had entirely disappeared, the shoots were left, with the cut ends in water, in an atmosphere of less than 30 per cent. relative humidity for 48 hours without showing any signs of wilting. More than go per cent. of the stomata were at this time found to be perfectly closed. The relative transpiration rate in diffuse light of moist-air and dry-air leaves of nearly all the kinds of seedlings grown was carefully determined. Attempts to make use of very slender (and therefore quick-reading) burettes as potometers were not successful. It was found too difficult to attach the soft and readily crushed stems of @ young seedlings to the burettes in such a way as to be sure to obviate leakage. All losses by transpiration were therefore estimated by weighing the shoots and the tubes of water which contained them on a balance sensitive to 5™6. The relative humidity of the air in which the transpiration took place was measured by the sling psychrometer (sometimes twice) during each experiment. As might have been expected, the inequality of transpiration was found to be greatest in the case of fully developed leaves, half-grown ones showing less, though notable, differences. The values given below are for the ratio M/D, in which M is the transpiration of the moist-air leaf and D the transpiration of the dry-air leaf. ; In discussing the results above given, it should be noted that a considerable range of values in the ratios obtained is almost unavoid- able. In the first place we have to reckon with the great variability of transpiration in individuals of the same species grown under identical conditions. F. Hapertanpr® found in the case of rye plants that the transpiration per day varied (in round numbers) from 2 to 7™ per square decimeter for different individuals. Also, if the transpiration were allowed to take place in a nearly saturated atmos- phere (to prevent sudden wilting), the leaves would be under condi- 6 HaBERLANnr, F., Wissensch.-prakt. Untersuchungen auf dem Gebiete des Pflanzenbaues 2:146. Wien. 1877. Ree Oa ye ee Biny: pe re 3 P ¢ I) ok penne r y eed i ae weL ¥ ‘ yi PEER eal OE RET enon ” b ay Pe we ee ae ee ee ee Ee eee ee ee mee eg fy ae te Oe eee ie eens eee WEE Sey ee ay eee Pes) eee tN PN eMC Tred TT ER ND Re. Lae ene ee ee mere Peer So ee ey eee t9g09] BERGEN—TRANSPIRATION IN YOUNG SEEDLINGS 281 tions abnormal for the kinds of plants studied. If the atmosphere were to be made very dry, the leaves grown in very damp air would wilt inside of five minutes or less and die in a comparatively short time. In some cases it was found best to determine the transpiration of readily wilted leaves for a period of fifteen minutes and compare TRANSPIRATION RATIOS Kind of leaf Rel. humid. during trans. period | Ratio M/D Phaseolus 25 { 2.2 Phaseolus 63 2.5 Phaseolus.........- 64 3:2 LAPINUSS. 32 ok 26 4.0 DDI OUS . 25:5: o as , about 43 8.2 GUDINUS, fess ee ae | about 38 To.0 LUpinus.ccss5 eee | variable, probably over 40 1.9* Mirabilis. iH 36 3-9 Mirabilis... 2. 603 29 4.8 Tpomoea.)....4,. 080. 26 / 7-4 SAW Sos seca 34 6.6 OAiVide aA ee Fin 8.9 SINE PIS ss gc ks 28 3-5 Snewmis. ge 24 3g Cueumia:s. so is20s 34 | 9-3 Mieptiaia... co.cc about 50 oe * Young leaves, only half grown or less. t The moist-air leaves transpired on May 42 in air of 28 per cent. relative humidity, and the dry-air ones on May 13 in air of 34 per cent, relative humidity. this with the (calculated) fifteen-minute loss of the dry-air leaf of the same species, allowed to transpire for one or two hours. Oxalis corniculata from saturated air became wholly wilted inside of one minute, on being removed from the glass case, so its transpiration tatio could not be determined. It would be interesting to compare the Telative transpiration of the two kinds of leaves in extremely dry air minute by minute, but weighings on a balance delicate enough for this purpose could not be made with sufficient rapidity. The conditions as regards relative humidity were intentionally Varied a good deal, in order to show whether the transpiration ratios follow closely the changes in humidity. It is evident that in Phaseolus and Lupinus they do not. hile no experiments were made with a view of measuring the absolute rates of transpiration of the plants studied, all under the same conditions of temperature and humidity, it may be worth 282 BOTANICAL GAZETTE [ocToBER 4 while to give the values obtained for moist-air leaves of some of them. ‘TRANSPIRATION OF I00 SQ. CM. OF LEAF IN AN HOUR Plant ite ces go i a Pager ti Cucumis? 5 20 34 1485 Lupinus....... "21.67 43 3596 Nicotiana..... QE.tt 50 or less Ig50 Phaseolus. .... 26.11 2 1647 napis 22.22 28 2135 Summarizing the results obtained from the transpiration measure- ments,’ it may be said that: _1. As a result of being grown in a highly humid atmosphere, all the plants studied acquire a much greater than normal capacity for transpiration in a moderately dry atmosphere. 2. Different families and different genera of the same family vary greatly in their capacity to acquire by such culture a tendency to extremely rapid transpiration. 3. The transpiration ratios, for the same species, become notably greater as the leaf becomes fully developed. 4. The transpiration ratios are not necessarily greater when the 7 relative humidity of the air, during the period when transpiration 15 measured, is very low than when it has a medium value. CAMBRIDGE, Mass. 7 Not nearly all of these results have been tabulated in the preceding pages- A REMARKABLE AMANITA? GEORGE F. ATKINSON (WITH EIGHT FIGURES) During the autumn of 1908 I received from Mrs. VircrIniA Gar- _ LAND Batten, of Brookdale, Santa Cruz Co., Cal., a number of _ Specimens of an Amanita which presents several remarkable pecul- larities in its development and environic relations. | For several years _ Mrs. BALLEN has observed this Amanita and has made a careful field _ Study of the more salient features of its development. This account _ of the fungus is based on fresh specimens and photographs which she _has sent me, and upon her notes and descriptions, which show a temarkable appreciation on her part of the important morphological _ Characters, as well as of important features of development. This plant grows in the mountain forests of California. It is _ among the largest species of Amanita, the cap being 10 to 22°™ in _ diameter, one of the larger ones, according to Mrs. BALLEN, being : Sufficient for a meal. It thus rivals in size the royal Amanita of E Europe, which it surpasses in robustness, though not possessing its ; Nich orange-yellow color, and not attaining the height of the larger _ Specimens of that species. It is interesting to note that the stocky character of this plant with its short stem is probably an expression : of One of its environic and seasonal relations. It occurs in the high 4 Sierras and in the Coast Range. Probably the entire summer season : 1S needed for the growth and extension of the mycelium in the forest _ Mold, so that the huge fruit bodies are developed in late autumn and : early Spring. While we have as yet no information bearing on the € of origin of the fundament of the fruit bodies, it is likely that : all of them are formed during the summer and late autumn, and that _ the second crop, which appears early in the spring, is composed of Plants which have lived through the winter in a partially developed | ondition. The autumn crop ceases about the last of December, _ While the spring crop begins about the middle of March. * Contribution from the Department of Botany, Cornell University, No. 135. 283] [Botanical Gazette, vol. 48 284 BOTANICAL GAZETTE {OCTOBER In the high Sierras, where it is colder, the plant is well protected from frost injury, since it rarely if ever appears above the carpet of leaves covering the forest floor. Here it grows about the pines and firs. It has here almost become a subterranean fungus, a remarkable Fic. 1.—Partly expanded plant, showing calyptra of volva closely adhering to the pileus, the veil with the floccose remnants of the fundamental tissue between it and the stem, and the limb of the volva at base of stem. thing for an Amanita. Thus it is difficult to find, the only evidence of its presence being the mounds of conifer needles which the hidden plants raise above them, Uncovering these and removing the plant there is a large cone-shaped hole in the soil made by the pressure of the very thick stem and cap. They are often found in bitter cold -NOSNIAXLV ‘Ps GAN ‘reed S iS > S ™ VIINVAYV iG. -Three plants showing circumscissile dehiscence of the volva; the plant at the left with the delicate veil torn and (in front) the inner S tolice of the volva. 286 BOTANICAL GAZETTE [OCTOBER weather, when the ground is covered with snow, but are so well protected by the covering of needles and snow that they are perfectly fresh and uninjured, while a few hours’ exposure to the air results in their being frozen. In the Coast Range they are smaller and not so ; : nd sup- Fic. 3.—Partly expanded plant, showing veil attached at apex of BS isa : : = a ported in a divergent position by the mass of loose cottony remnants of the fum tissue lying between the veil and stem. bright-colored, and are found around the madrojfas, chestnuts, = pines, and spruces. Mrs. BALLEN has never found them around the redwoods. The spring crop is also paler than the autumn crop- In the mountains about Brookdale, Santa Cruz Co., they appeat above the ground. 1909] ATKINSON—A REMARKABLE AMANITA 287 The pileus is a maize-yellow in its bright-colored forms and varies toa pale straw color or Naples yellow (R.) in the vernal forms. The gills are at first white and later become tinged with the same color. The stem and inner veil or annulus are also tinged with pale straw é 3. 4.—Section of plant showing pendent veil and loose cottony fundamental ss & . ‘ Sue between it and the stem. Color. The volva is thick, stout, and white, though in age it becomes More or less soiled and tinged with yellowish brown. The pileus is broadly rounded in the young plants, becoming broadly convex to Plane, or in old plants the margin may become elevated, thus giving the pileus ; Pileus a depressed appearance. 288 BOTANICAL GAZETTE foCTOBER Very little of the surface of the pileus is visible, since all except a narrow marginal portion is covered with the calyptra of the volva, which forms a thick, white, tough skin or covering, closely and tightly fitting the cuticle of the pileus. In cutting through the calyptra and pileus the line of junction can be seen, and in fresh plants this line of division is brought out distinctly because of the pale-yellow cuticle of the pileus. This calyptra, covering the larger part of the pileus like lar of the volva, IG. 5.—The stem separating from the volva; note inner col striate margin of the pileus, and very distinct thick calyptra. a closely fitting cap, is often unbroken; but in large, well- expanded plants, it is often cracked into irregular large areas, as in fig: 9; 6, show- ing the pileus between. The inner veil is very thin and fragile, and disappears soon after the opening of the plant. When the plant is expanded the annulus is attached to the extreme upper end of the stem at the point of junction of the gills and stem, for the gills are adnexed, as in some other of Amanita, and the stem is not readily separable from the The plant is very fleshy, is often attacked by larvae, and readily ye so that transport of mature or nearly mature specimens is dificult. species pileus- 1909] ATKINSON—A REMARKABLE AMANITA 289 In the button stage they sometimes carry and keep well for several days. The inner veil is slightly connected with the edges of the gills and thus the expansion of the pileus produces a tension which tears the veil from the surface of the stem, with which it is also connected by G. 6.—Surface of pileus, showing calyptra torn into large patches, which remain 1 IG, tightly adherent to the pileus. “emnants of the fundamental tissue. This tissue, lying between the Veil and the stem, is very loose and floccose, so that it is torn into a delicate cottony mass, which often supports the veil in a divergent Position as it hangs from the apex of the stem (figs. 3, 4). The veil itself is very delicate in texture, and Mrs. BALLEN says that it “seems 'o melt away” soon after the expansion of the plant. This indicates that it is not well differentiated from the fundamental tissue. In 290 BOTANICAL GAZETTE [ocroBER buttons which were shipped to me, and which opened in transit or after reaching here, this inner veil did not separate from the stem, but remained as fundamental tissue clothing the stem (jig. 7, where the outline of the cortex of the stem is shown within). _ The stem is stout and comparatively short. The volva is circum- scissile, but the lower half, which remains attached to the base of the stem, is large, with an ample, stout, free limb forming a large sac-like structure resembling that of the Amanitas with apical dehiscence, though the edge is more even. Within the basal portion of the volva and surrounding the stem there is often present a narrow collar or secondary sheath, the origin and nature of which, to my knowledge, have never been carefully described in any Amanita, for it is usually overlooked. This inner collar or secondary sheath I have studied carefully in Amanita caesarea of Europe, while studying the higher fungi in the Jura Mountains of France, from specimens collected at Besangon and Arbois, in September, 1905. PLOWRIGHT? has called attention to 4 similar inner collar in specimens of Amanitopsis spadicea, and pro- posed to employ it in separating this species from A. livida, the two being usually brought together under this name, but he offered no- suggestion as to its significance or origin. I have observed it and studied its origin also in Amanitopsis livida Richon & Roze and do not think that much specific importance can be attached to it, since it varies so in strength in different specimens and is often so obscure when it remains, as it sometimes does, closely applied against the base of the stem. Great credit, however, is due to Mrs. BALLEN for having made such careful observations on the presence and nature of this interesting structure in the California Amanita, the more S° since there is no published description of such a structure, and her observations, though later than mine on Amanita caesarea and Amanitopsis livida, were entirely independent of them, and made before she had called my attention to the existence of this species. Longitudinal sections of the young plants when in the more advanced “egg” stage show all of the principal parts well formed. The pileus and stem when cut or bruised often turn a pale straw > Trans. Brit. Mycol. Soc. 1897-8:40. See ATKINSON, Mushrooms, edible, poisonous, etc. 75. st ed. 1900, Ithaca. 2d ed. rgor, Ithaca, and 1993; New York. . 7.—Plants ee after transit from California to Ithaca, N. Y., showing dehiscence; middle plant in section, showin very iy the thic of the calyptra; inner veil remaining attached to the stem and continuous below with the tissue that forms the collar on ie toate of the volva, indicating that all of the tissue which lies between the cae and the gills is hindus issue. —_ [606r ATAVHIYVNAY V—-NOSNIXNLV VLINVAV 2Q2 - BOTANICAL GAZETTE {OCTOBER yellow on exposure of the cut surface to the air. In such sections of young plants therefore the pileus is clearly marked off from the sur- rounding volva, and the wall of the stem is likewise marked off distinctly from the surrounding fundamental tissue. The gills are also well outlined. The slightly convex outline of their edge does not permit them to lie against the surface of the stem, and their lower or outer ends curve away from it in the young stage. This space is filled with fundamental tissue, and as the plant expands it is left free from Fic. 8.—Photomicrograph of spores with Zeiss ocular 18, objective 37; object 370™m from plate-holder. the stem and gills, but attached to the inner side of the base of the volva as a collar around the stem. When the plants become quite mature or old, there are tissue changes at the base of the stem inside of this collar which permits the stem to be very easily separated from the volva. By this time the free limb of the volva has recurved more of less, leaving the volva in the shape of a saucer with a recurved edge, and an inner collar. At this stage, if one takes hold of the cap to lift the plant, the stem is freed from the volva cup, leaving this saucer” shaped structure in the ground. Fig. 5 is from a photograph of this stage, showing this saucer-like structure of the volva with its inne collar, and the freed stem at one side. In dry weather this separation of the stem from the volva does not take place. I have proposed the name Amanita calyptroderma for this plant, ee Le ee Fo) ee, ea ne Pte Teak ee et em eee “Erato Tra TE) Oe SE ee ; x ; 3 E 3 E 1909] ATKINSON—A REMARKABLE AMANITA . 293 because the calyptra of the volva fits like a skin over the center of the pileus. Although a technical description has been published else- where,’ it may be well to add a diagnosis here. AMANITA CALYPTRODERMA Atkinson & Ballen.s—Plants 1o-15°™ high, pileus 10-22°™ broad, stem 2-4°™ stout. Pileus maize-yellow to pale chrome-yellow, gills white, then pale maize to cream color, annulus and stem pale maize to cream color, volva white. Pileus stout, fleshy, convex to expanded and even depressed in age, margin striate, slightly viscid when moist, larger part of pileus covered with the tough thick calyptra of the volva which fits closely like a skin, the margin free, while in age in the larger plants the calyptra of the volva is cracked into rather large areas by the expansion of the pileus. Gills broad, adnexed, edge more or less floccose. Basidia 4-spored. Spores oval to elliptical, smooth, coarsely granular, 8-12 7-8 Bb. Annulus very thin, membranaceous, superior, hanging from the extreme apex of the stem, soon disappearing. Stem hollow, with loose cottony threads, even in the smaller plants, tapering upward in the larger ones, or smaller at base, surface floccose. Volva white, thick, circumscissile, in dehiscence the upper part remaining on the center of the pileus, lower portion of limb very prominent, 2-4°™ long, sometimes appressed on the stem, but usually distinctly divergent and in age recurved, often with a distinct inner collar near the base, in age the stem often separating from the volva, leaving the latter as a saucer-shaped structure with its inner collar in the ground.— Mountain forests, California, in late autumn and early spring, Mrs. Virginia Garland Ballen. WHerb., Cornell Univ., no. 22620. * Science N. S. 293944. 1909. | Closely related to Amanita calyptrata Peck, Bull. Torr. Bot. Club 27:14. *909, but differs in color and other characters. UNDESCRIBED PLANTS FROM GUATEMALA AND OTHER CENTRAL AMERICAN REPUBLICS. XXXII" : JouHn DoNNELL SMITH Pithecolobium (§SaAMANEA Benth.; Ser. Carnosae Benth.) cate- natum Donn. Sm.—Folia ampla, pinnis unijugis, foliolis 3-5-Juss obovato-oblongis vel -ellipticis obtuse cuspidatis basi acutis, stipulis uti glandulae interpetiolulares obsoletis. Pedunculi axillares longis- simi. Legumen lineare longissimum moniliforme polyspermum bivalve, loculamentis atque seminibus ellipsoideis. Frutex, ramis petiolis pedunculis ferrugineo-puberulis. Petiolus communis 4-8™ longus, pinnarum erecto-patentium rhachi 12—22°™ longa, foliolis chartaceis praeter costam utrinque puberulam glabris subtus pallidioribus in eodem jugo inaequalibus per ae deorsum decrescentibus, supremis r1-16°™ longis 5-7.5™ latis, infimis 3-9°™ longis 2-4.5°™ latis, nervis lateralibus utrinque 6-7, venulis subtus minutissime reticulatis, petiolulis 2-3™™ longis. Pedunculi 8-18°™ longi, floribus sessilibus. Legumina crasse coriacea rubiginoso-subvelutina addito stipite 12-22™™ longo 24-26°™ longa epulposa demum dehiscentia inter semina arcte constricta, loculamentis 15-17™™ longis g-11™™ crassis leviter compressis, isthmo infimo interdum 12-14™™ longo, ceteris 2-4™™ longis, seminibus 11-1? circiter 13-15™™ longis 8-10™™ latis atrocoloribus, hilo subapicali—Florum tantum reliquiae visae. Ad P. sophorocarpum Benth. legumine semine embryone accedens foliis longe distat. _ In silvis profundis ad praedium Swerre vocatum, Llanuras de Santa Clara, Comarca de Limén, Costa Rica, alt. 300", Febr. 1896, John Donnell Smith, n. 6479 ex Pl. Guat. etc. quas ed. Donn. Sm Appunia guatemalensis Donn. Sm.—Glabra. Stipulae breviter vaginantes bicuspidatae. Folia subsessilia magna elliptico- Vv vel obo- vato-oblonga utrinque acuminata. Capitulum singulum pauci- et laxi-florum, bracteis ovario paulo longioribus glandulis 1-3 cuspidatis. Calyx campanulatus truncatus basi glanduligerus quam corolla octies brevior. Frutex. Stipulae coriaceae acuminato-triangulares 3™™ longae, cuspidipws minutis. Folia subcoriacea utraque pagina nitentia 13-16°™ longa me edio vé petiolis 2-3™™ longis. Pedunculi axillares 3.5-4°™ longi, one ae 7-floro absque corollis 5-6™™ longo atque lato, oils acuminato-o ‘ Continued from Bot. GAZETTE 47: 262. 1909. [204 Botanical Gazette, vol. 48] : 1909] SMITH—PLANTS FROM CENTRAL AMERICA 295 longis, floribus heterogoneis (brevistylis solum visis). Calycis 2™™ longi in sicco nigricantis tubus hemisphaericus limbum aequans, glandulis linearibus paucis. Corolla 16™™ longa ad 2™™ supra basin staminigera. Antherae subsessiles 3™™ longae. Discus 0.5™™ altus. Ovarium 1™™ longum, stylo uti stigma pyramidale ™™ longo. Bacca ignota. In silva prope pagam maritimam Livingston, Depart. Livingston, Guate- mala, Jun. 1906, H. von Tuerckheim (n. IL. 1230). Palicourea (§Crocornyrsus Griseb.; Ser. Croceae Muell. Arg.) leucantha Donn. Sm.—Glabra. Stipulae vaginam amplam laxam truncatam subaequantes. Folia elliptico-oblonga utrinque acuminata. Thyrsus .elongatus, axibus angulosis, bracteis bracteolisque majus- culis. Calycis limbus alte partitus ovario 2-4-plo longior. Corolla alba ad } altitudinis paleaceo-annuligera. lat toe lineari-lanceolatae re etia se Internodia obtuse tetragona. Stipul j longae. Folia subtus minute puberula 14-17°™ longa medio 4-7“ lata, petiolis lineari-lanceolatis 4-9™™ longis, cymis dichotomis, pedicellis 3-9™™ longis. Computatis lobis 2™™ longis 15-16™™ longa margine virescens paleis niveis annuligera ad 3 altitudinis staminigera. Antherae medio e 2™m Jon filamenta aequantes apice exsertae. Discus hemisphericus 1.5™™ altus. Ovarium — cylindricum y-1.smm longum atque crassum biloculare, stylo 7™™ longo, lobis T.5™™ longis. Bacca deficit.—P. mexicanae Benth. affinis. In silva montana ad viam inter Coban et Tactic, Depart. Alta Verapaz, Guatemala, alt. 1800™, Mart. 1903, H. von Tuerckheim, n. 8400 ex Pl. Guat. etc. quas ed. Donn. Sm.—In monte prope Coban, Depart. Alta Verapaz, Guatemala, alt. r650™, Jun. 1908, H. von Tuerckheim (n. II. 2282). Parathesis microcalyx Donn. Sm.—Folia lanceolato-obovata Cuspidato-acuminata in petiolum attenuata integra supra glabra Subtus glabrescentia. Panicula terminalis foliis superata. Calyx brevis, lobis deltoideis tubum aequantibus. Corolla staminibus bis longior. Ovarium apice pubescens totum post anthesin calyce aequilongo arcte cinctum depresso-globosum. : Folia recentiora subtus cum ramulis petiolis "panicula{floribus ferrugineo- Pubescentia, provectiora glabra erga lucem inspecta punctulis et lineis pellucida, Saltem Superiora (solum visa) g-12.5°™ longa 3.5-4™ lata, petiolis I-t. 5°™ longis. 296 BOTANICAL GAZETTE [OCTOBER longae acutae lineato-maculatae intus glabrae. Antherae ovatae 1™™ longae area dorsali atra deltoidea epunctatae filamentis bis longiores. Ovarium corolla jam delapsa 1™™ longum paulo latius quam longius, stylo 2.5™™ longo. Fructus age ae —P. serrulatae Mez proxima. n fruticetis secus rivulum ad fundum La Colombiana dictum, Llanuras de as Clara, Comarca de Limén, Costa Rica, alt. 200™, Jun. 1899, H. Piitier, n..7591 ex Pl. Guat. etc. quas ed. Donn. Sm. (n. 13410 herb. nat. Cost.). Gonolobus (§Monostemma K. Schum.) leianthus Donn. Sm.— Folia longe petiolata sparsim pilosiuscula ovato-oblonga acuminata sinu profundo rotundato cordata. Pedunculi biflori et pedicelli graciles, floribus glabris inter maximos. Segmenta corollina lan- ceolato-oblonga parum reticulata calycinis ovatis sesquilongiora. Corona tenuiter annularis subintegra gynostegio brevissimo adnata. Frutex volubilis, ramis petiolisque patenter pilosis vel glabrescentibus, pedun- culis pedicellisque glabris. Folia g-12°™ longa 3.5-5°™ lata supra paene glabra subtus setulis minimis aspersa, petiolis 6-8°™ longis. Pedunculi 2-4™ longi, pedicellis inaequalibus 3-5°™ longis, floribus 5°™-diametralibus. Calycis seg- menta paene sejuncta late imbricata herbacea 13™™ longa 5™™ lata acuminata. Corollae alte fidae segmenta 2°™ longa 7-9™™ lata acute elongata carnulosa in sicco badia erga lucem inspecta reticulata. Corona callis contiguis minutis multidenticulata mediantibus carinis tenuibus gynostegio connexa annulo mem- branaceo pubescente corollae adnato comitata. Gynostegium vix 1™™° altum 6™™-diametrale——G. macrantho Kunze proximus. Cubilquitz, Depart. Alta Verapaz, Guatemala, alt. 350™, Oct. 1901, H. vam Tuerckheim, n. 8243 ex Pl. Guat. etc. quas. ed. Donn. Sm. Trichostelma oblongifolium Donn. Sm.—Folia Janceolato-ob- longa cuspidato-acuminata basi acuta vel obtusiuscula. Cymae sessiles. Segmenta corollina calycinis lanceolatis bis longiora ovato- lanceolata cymbiformia apice cucullato recurva. Corona exterior parce longeque ciliata, interior breviter cupularis vix lobata. Gyno- stegium breve appendicula paulo longius. Suffruticosum volubile patenter pilosum. Folia discoloria utrinque bulbosis aspersa 8-11°™ longa medio 3-5°™ lata, nervis subtus fusco-villosis, petiolis “1-2 longis. Pedicelli 3-5-fastigiati_1.5-3.5°™ longi, floribus extus carnulosa to-loba extus eaccee A sched a gynostegio flinch ube I. ae longa lobis divaricatis 3™™ lata. Pollinia pendula oblongo-elliptica eeere paulo longiora. Folliculi desunt—A specie hactenus unica, T- ciliato (Fimbristemma calycosa Donn. Sm. ), foliis atque floribus optime distinctum. 1909] SMITH—PLANTS FROM CENTRAL AMERICA 207 In fruticetis ad Panzal, Depart. Baja Verapaz, Guatemala, alt. rooo™, Apr. 1907, H. von Tuerckheim (n. Il. 1747). Solanum (§ LeEropENDRA Dun.) Rovirosanum Donn. Sm.— Folia gemina parum inaequimagna elliptica vel obovato-elliptica bis longiora quam latiora in Sectione maxima sursum in angulum acutum vel obtusum desinentia in petiolum brevem plus minus attenuata, nervis lateralibus utrinsecus 6—7 ad axillas nudis. Pedicelli, cymoso-fasciculati numerosi graciles, floriferi cernui, fructiferi erecti. Frutex omnibus in partibus glaber. Folia pergamentacea concoloria nitida 19-30°™ longa 9-14.5°™ lata, altero circiter quinta parte minore, petiolis 8-18"™ longis. Pedunculi ro-24™™ longi nonnunquam furcati, pedicellis floriferis 6™™ longis, fructiferis 11™™ longis. Calyx obpyramidalis 2.5™™ longus, lobis tubo bis brevioribus rotundatis calloso-apiculatis. Corollae tubus 1™™ longus, laciniae lanceolatae 6—7™™ longae. Antherae conniventes oblongae 3™™ longae 1™™ latae nigricantes ad apicem luteum poris anticis amplis ellipticis dehiscentes, filamentis complanatis 1™™ longis. Ovarium ovoideum, stylo 5™™ longo. Bacca nondum satis matura calyce accrescente cincta globosa 7™™-diametralis nigra. Cubilquitz, Depart. Alta Verapaz, Guatemala, alt. 350™, Aug. 1904, H. von Tuerckheim, n. 8716 ex Pl. Guat. etc. quas ed. Donn. Sm.; Jul. 1907, H. von Tuerckheim (n. II, 1888).—Eandem plantam collegit José N. Rovirosa in Mexico ad Mayito, Estado de Tabasco, Jul. 1889, et sub numero 544 distribuit. Athenaea cernua Donn. Sm—Glandulari-puberula. Folia gla- brescentia plerumque solitaria ovata cuspidato-acuminata basi Cuneata vel rotundata. Pedunculi axillares vel dichotomales solitarii, flore atque fructu cernuis. Calycis lobi elongato-triangulares sub anthesi tubo paulo longiores. Corollae limbus campanulatus triente lobatus, lobi deltoidei. Bacca coccinea. Herbacea, ramis dichotomis sulcatis et petiolis glandulari-puberulis. Folia membranacea punctulata nervis et margine puberula 4-7.5°™ longa 2.5-4™ lata Integra interdum gemina, altero consimili triente minore, petiolis 1.5-3°™ longis. Pedunculi 2.5-3.2°™ longi subglabri, floribus 7"™ longis. Calyx glandulari- Puberulus 3-5™™ longus, lobis sub anthesi 2™™ longis. Corollae luteae tubus cylindricus ym longus, limbus abrupte ampliatus basi staminigerus, lobi 2-2.5™™ longi ciliolati. Antherae ovales 2™™ longae 1™™ Jatae filamentis subaequilongae. Ovarium ovoideum 1.5™m™ longum, stylo 3.5™™ longo. Bacca globosa Ae diametralis calycis aucti lobis 3.5™™ longis obvelata, seminibus fusci bi latis In silva ad praedium Sasis, Depart. Alta Verapaz, Guatemala, alt. goo™, Maj. 1908, H. von Tuerckheim (n. II. 2245). Brachistus ceratocalycius Donn. Sm.—Glabrescens. Folia lan- Ceolata e medio utrinque acuteque angustata plerumque solitaria, 298 BOTANICAL GAZETTE {OCTOBER floralia gemina homomorpha subaequimagna. Pedunculi singuli vel 2-4-ni. Calyx medio infra marginem truncatam scariosam tuber- culis 10 appendiculatus. Corolla infundibularis paulo ultra medium lobata. Antherae ellipticae filamentis altero tanto longiores. Frutex, ramulis novellis furfuraceis. Folia 7-10°™ longa 1.7-2.5°™ lata supra primum puberula mox utrinque glabra, nervis lateralibus ideas 5-6, venis transversis parallelis remotis parum manifestis, petiolis 5-12™™ longis et " pedunculis calycibusque puberulis. Pedunculi 15-31™™ longi erecti. Calyx hemisphaericus 3.5™™ altus, margine scariosa 1™™ lata, tuberculis squarrosis subconicis. Corolla violacea (cl. repertor in scheda), 16-17™™ longa in alabastro griseo-pubescens, lobis lanceolatis ad apicem versus et ad margines pubescentibus. Antherae 5™™ longae 2.5™™ latae apiculatae margine exteriore dehiscentes. Ovarium ovoideum 2.5™™ longum in stylum aequilongum attenuatum. Bacca ignota. In silva montana prope Coban, Depart. Alta Verapaz, Guatemala, alt. 1600”, Jan. 1908, H. von Tuerckheim (n. II. 2060). Ruellia (§ DipreracantHus Baill.) pygmaea Donn. Sm.— Folia approximata minima oblongo-ovata acuminata basi acuta integra supra paleaceo-pilosa subtus nervis ferrugineo-strigillosa. Flores ad axillas oppositas foliorum superiorum subsessiles, bracteis linearibus calyce paulo longioribus corolla 5-6-plo_ brevioribus. Capsula puberula 4-sperma infra medium contracta et compressa. Caules € rhizomate longe repente foliis abortivis munito passim ascendentes 6-8" longi simplices et petioli ferrugineo-strigillosi. Folia internodiis longiora superne imbricantia 13-25™™ longa 7~-10™™ Jata supra pilis longis articulatis aspersa utrinque lineolata, nervis lateralibus utrinsecus 4, petiolis 2-3"™ longis. Bracteae 4-5™™ longae paleaceo-pilosae. Calycis puberuli tubus 1.5™™ altus, segmenta linearia 2-2.5™™ longa. Corolla extus puberula 24™™ longa supra basin cylindricam 8"™ Jongam sensim et aequaliter ampliata faucibus 5™™ lata, lobis late rotundatis 3™™ longis. Stamina bene inclusa, antheris 2”™ lene Capsula oblongo-ellipsoidea 8-9™™ longa acuminata sulcata, parte solida A longa, seminibus orbiculatis 2™™-diametralibus margine cano-pubescentibus. ai R. humijusae Hemsl. proxima. : Hacoc prope Cubilquitz, Depart. Alta Verapaz, Guatemala, alt. 600™, Maj. 1904, H. von Tuerckheim, n. 8725 ex Pl. Guat. etc. quas ed. Donn. Sm. Ruellia (§ Puysrevert1a Lindau; Ser. Eglandulosae Lindau) guatemalensis Donn. Sm.—Folia glabra ovata vel lanceolato-ovata acuminata basi angustata vel rotundata margine undulata. Flores subsessiles 1-4-ni axillares vel in cymis axillaribus terminales ¢t dichotomales, cymis folia superantibus, axibus elongatis, bracteis 1909] SMITH—PLANTS FROM CENTRAL AMERICA 209 - longissimis. Corolla usque ad medium cylindrica tum ventricoso- infundibularis. Frutex, ramis obtuse tetragonis minute cystolithigeris, angulis et nodis puberulis. Folia chartacea utrinque praesertim supra lineolata 9.5-10.5°™ longa 3.5-4°™ lata, vel superiora magis ovata 5°™ longa 2.5°™ lata, nervis latera- libus utrinsecus 4~5, petiolis puberulis canalicularibus amplexicaulibus 10-18™™ longis. Cymae nondum satis evolutae addito pedunculo 5-8°™ longo 10-14°%™ longae puberulae parce furcatae pauciflorae, axibus erecto-patentibus 1.5-3.5°™ | longis, bracteis linearibus 2— 3™™ longis, bracteolis lanceolatis 2™™ longis. Calycis tubus 2™™ longus, segmenta linearia 7™ longa. Corollae tubus totus 3°™ longus, pars cylindrica 1.5™™-diametralis, lobi obovato-orbiculares 8™™ longi emarginati. Stamina inclusa, filamentis per paria leviter connatis, majoribus 8™” longis minores dimidio superantibus, antheris 2.5"™ longis. Discus 0.5™™ altus. Ovarium glabrum oblongo-lineare 5" longum 12-ovulatum triente contractum et vacuum, stylo puberulo 31™™ longo. Capsula matura ignota. Ad praedium Concepcién vocatum, Depart. Escuintla, Guatemala, alt. 400™, Apr. 1890, John Donnell Smith, n. 2115 ex Pl. Guat. etc. quas ed. Donn. Sm. (Sub Ruellia. sp. olim distributa.)—Ad ripas fluminis Ocosito prope pagum Caballo Blanco, Depart. Retalhuleo, Guatemala, alt. 80", Apr. 1892, John Donnell Smith, n. 2692 ex Pl. Guat. etc. quas ed. Donn. Sm. Pseuderanthemum verapazense Donn. Sm.—Folia lanceolato- oblonga in acumen obtusum angustata basi acuta praeter costam subtus viscidulo-puberulam glabra. Spica terminalis simplex vel Tamis binis aucta bracteis foliaceis lineari-oblongis fulta, bracteolis triangulari-linearibus calyce bis brevioribus, floribus singulis subses- silibus. Caules e rhizomate longe repente hinc illinc erecti subsimplices 1o~25°™ longi teretes bifariam viscido-pubescentes. Folia lineolata 5-7°" longa 18-20"™ lata, petiolis pubescentibus 3-4"™ longis. Spica puberula 3-7°™ longa, ramis 2-3™ longis, bracteis 12™™ longis 3™™ latis, bracteolis 1.57™ longis et floribus Puberulis. Pedicellus o.5™™ longus. Calycis segmenta linearia acute attenuata 3-3-5™™ longa. Corollae laete azureae (cl. repertor in schedula), tubus 16™™ longus triente superiore paulo ampliatus ceterum vix o.5™™-diametralis, lobi ongis. Ovarium puberulum 4-ovulatum, stylo 16™™ longo bilobo. apsula ignota.—P. hispidulo Rad\k. proximum. In silvis montanis ad Yaxcabnal, Cubilquitz, Depart. Alta Verapaz, Guate- mala, alt. 320™, Mart. 1902, H. von Tuerckheim, n. 8258 ex Pi. Guat. etc. quas ed. Donn. Sim. Dicliptera (SSpHENOsTEGIA Nees) podocephala Donn. Sm.— Folia breviter petiolata ovato-lanceolata subsensim acuminata basi 300 BOTANICAL GAZETTE [OCTOBER angustata. Pedunculi axillares 1-3-ni elongati monocephali, captulis lineari-bracteatis, involucris 3-8 uni- vel bi-floris, phyllis involucrali- bus apice rotundato cuspidatis, bracteolis 4 calyce bis longioribus. Corolla paulo exserta. Fruticulosa 1-1.5-metralis diffusa, ramis obtuse sex-angularibus uti petioli pedunculi involucra lineolatis et puberulis. Folia membranacea glabra cystolithis striolata 8.5—-12.5°™ longa 3.5-4.5°™ lata, petiolis 13~17™™ longis. Capitula omnia pedunculata, pedunculis 1-9. 5°™ longis in axillis superioribus singulis, in inferioribus binis vel ternis inaequalibus. Bracteae capitula semicircularia fulcientes binae 4~7™™ longae, involucris plerumque 5, exterioribus decrescentibus, phyllis obovatis basi cuneatis pergameneis nervosis reticulatis per paria inaequi-. magnis, majore 11-14™™ longo 8-9”™ lato in statu sicco colorato, altero quarta parte minore viridi, bracteolis lanceolato-linearibus 8™™ longis, flore altero abortivo vel deficiente. Calycis laciniae setaceae cum bracteolis puberulae. Corolla 14™™ longa, limbo pubescente. Antherarum loculi inaequialte affixi. Stylus 12™™ longus. Capsula pubescens ovoidea 5™™ longa apiculata disperma, seminibus puberulis 2.5™™-diametralibus. In pratis humedis ad praedium Atirro vocatum, Prov. Cartago, Costa Rica, alt. 600", Apr. 1896, John Donnell Smith, n. 6685 ex Pl. Guat. etc. quas ed. Donn. Sm. Justicia (§ DIANTHERA Lindau) Tuerkheimiana Donn. Sm.— Pilosa eglandulosa. Folia oblongo-ovata apice obtusiuscula basi cuneata sparse paleaceo-pilosa. Spica terminalis pedunculata folia superiora subaequans, bracteis laxe imbricatis lanceolato-ellipticis. Calycis segmenta acuta. Corollae tubus tenuissimus. Herba procumbens diffusa ad genicula radicans 23-30 longa, ramis obtuse tetragonis et petiolis et pedunculo patenter pilosis, glandulis obsoletis. Folia ejusdem paris parum inaequalia 23-38™™ longa 12-19™™ lata lineolata, nervis lateralibus utrinsecus 4-5, petiolis 4-10™™ longis. Pedunculus circiter be ignota.—J. Schenckianae Lindau arcte a : Ad fissuras saxorum, Cubilquitz, Depart. Alta Verapaz, Guatemala, alt. 350™, Jun. 1903, H. von Tuerckheim, n. 8726 ex Pl. Guat. etc. quas ed. Donn. Sm. BaLtimore, Mp. Tea poe gies Dene he ene eee va ee BRIEFER ARTICLES NEW NORMAL APPLIANCES FOR USE IN PLANT PHYSIOLOGY. V*. (WITH TWO FIGURES) In the preceding articles I have described some ten new pieces of apparatus designed for educational work in plant physiology; accounts of three more are given below, while others are to follow. They are called _ hormal appliances because they are intended to represent the optimum resultant, the harmonic optimum, as it were, between accuracy of results and convenience of use, while at the same time they can always be bought from the stock of a supply company. As in the case of the other pieces these are to be manufactured and sold by the Bausch & Lomb Optical Company of Rochester, N. Y¥ X. Space markers For some purposes, especially in the study of growth, it is necessary to mark off a structure into regular divisions, either areas as in the case of young leaves, or lengths as in roots, stems, or petioles. It is not difficult to improvise appliances for accomplishing these ends, but as yet no tools are available for effecting them quickly, accurately, and conveniently, while at the same time always ready for use. This need, I think, the two little instruments here described will supply. First, for marking lengthwise, the instrument is a wheel, the rim of which is a rubber stamp having raised cross-lines 2™™ apart. It revolves freely but evenly on an axle held in the end of a handle, and when suitably inked by the method described below, it may be run rapidly over long struc- tures such as roots, marking them with narrow black cross-lines equally spaced, precisely as shown at the bottom of jig. I. econd, for marking areas, the instrument is a disc, likewise @ rubber stamp, haying raised lines in the form of squares 2™™ on a side. It works by means of a scissors-frame against a cushion disc covered with soft felt and provided with a radial slot to admit the petiole of a peltate leaf. When the marking disc is inked and pressed firmly against a leaf held .on the Cushion disc, it marks a network of even fine black lines like the sample shown in jig. r. The marking disc is hinged to its supporting arm ms * Continued from Bor. GAzETTE 43:279. April 1907. | [ 30r] Botanical Gazette, vol. 48 302 BOTANICAL GAZETTE [ocTOBER way to permit the disc to settle evenly upon the leaf surface no matter what the thickness of the leaf. Both instruments may be inked from an ordinary rubber-stamp pad, and the black record kind gives good results. Better, however, is a simple Fic. 1.—Space markers. x }. pad made from one fold of thin close cotton cloth attached by thread to an ordinary glass slide, and inked when needed by a mixture of three parts Higgins’ waterproof India ink and one part glycerin. XI, Demonstration auxograph Among the most important of the topics which all teachers desire to demonstrate in general botanical courses is growth, and this can be shown to complete satisfaction only through use of a recording instrument. Many recording auxanometers, or auxographs, have been described, but as yet n° practical instrument for educational purposes is obtainable by purchase. The essentials of a good demonstration instrument, aside from easy applica- bility to its work and durability, are reasonable accuracy, ready portability, visibility of record from some distance, and clear exhibition of its mechan- ism and principle. These ends, I believe, are well met in the instrument here described and illustrated (fig. 2). : It consists essentially of four parts: support-stand, recording cy linder, magnifying wheel, and plant-support. The support-stand is of rigid 1909} BRIEFER ARTICLES 303 though thin steel, and is provided with convenient handles, leveling screws, and suitable holes for the two upright rods. The recording cylinder, Fic. 2.—Demonstration auxograph. 4. Supported and guided at the top by a screw pivot, turns once an hour, and is of such circumference that each millimeter of a millimeter record paper represents one minute. It is carried by a clock which is supported at such 304 - BOTANICAL GAZETTE [ocropER — a height that it may be wound and regulated from beneath without disturb- ing the record. The magnifying wheel, really four concentric wheels combined, allows three degrees of magnification, two, four, and eight times the actual growth. It is made of aluminum, moves on a very sensitive axle, has suitable openings for attachment of threads, and is provided with a clamp for holding it immovable while adjustment of threads and the like is being made. The tip of the plant is brought into action with the wheel by means of a fine thread in the usual way; but in order that this thread may be kept as short as possible, a plant support, adjustable for height, is provided on a separate rod, thus permitting the tip of the plant to be kept close to the magnifying wheel, though, of course, care must be taken to prevent the danger of shading, and hence of phototropic bendings. This adjustable support, however, has another very important use which will be mentioned below. The thread from the large wheel passes over a _ pulley to the pen carrier, which slides on a fine guide wire and has sufficient weight to turn the wheels in proportion as the growth of the plant permits the small wheel to turn. The pen is of glass, drawn to a capillary point and bent so as to rest at right angles to the paper. It is filled with chrono- graph ink, and, as the plant grows and the cylinder turns, it traces a fine spiral line down the cylinder, crossing any given vertical line once an hour. When this pen has reached the bottom of the cylinder, one has only to put on a new cylinder or record paper, turn the large wheel backward until the pen is drawn to its top, close the clamp to hold the wheel immovable, lower the plant support until the, thread from the plant becomes again taut, loosen the clamp to allow the tensions to adjust themselves, and then the record is resumed; and this procedure can be repeated until the end of the experiment without any need for ever touching the threads. This is the other advantage, above mentioned, of the adjustable plant-suppott. One should never draw up the pen by lowering the plant support, as there — is a constant temptation to do, since this brings an unnatural strain upon the plant tip. All parts of the instrument, even to the arms carrying magnifying wheel and pulley, are adjustable, so the instrument may be made to work smoothly under any conditions. While designed primarily for making records of growth, it can be used for any measurements involy- ing movement, e. g., the rise of water in a tube. The weak point of all auxographs lies in the threads, which will alter length hygroscopically and thus introduce error into the record, despite any known treatment with wax, oil, rubber, etc. These alterations may be minimized by treating the threads with wax, and by keeping them as short as possible, for which reason they should be made only long enough to 1909} BRIEFER ARTICLES 305 allow the turning of. the wheels, with no extra turns around the latter. The error, of course, is greatest from the thread attached to the plant, since its alterations of length are magnified in the record. Not only should this thread be kept short, but I think a glass filament could advantageously be substituted for all of its length except the loop at the plant and the partial turn around the wheel. The results of these errors can also be relatively minimized by using plants of the most rapid and vigorous growth, such as the flower-stalks of bulbous plants——W. F. Ganone, Smith College, Northampton, Mass. CURRENT LITERATURE BOOK REVIEWS Anisophylly A monograph on this subject has been prepared by Ficpor,' privat-docent in plant physiology in the University of Vienna. It is inspired by WIESNER, the distinguished physiologist of that university, and is dedicated to him. Naturally enough it is dominated by his views, and is interspersed with quotations from his writings. Ficpor has gathered together what is at present known regarding anisophylly and has presented (critically, he says) the subject from both the morphological and the physiological point of view. In space, at least, the former predominates; and it must be confessed that the physiology is too obscure yet to be very satisfactory. In the first section (36 pp.) the author defines the term, states the history of the phenomenon, and describes, as various sorts, incomplete, exorbitant, complete, lateral, habital, secondary, and false anisophylly. The second section (67 pp.) describes all the cases of anisophylly observed, in the systematic order from lycopods to composites, including cases of anisocotyly. The third section (55 pp-) causation; he intends to enumerate experimental work on all recorded cases, including new observations of his own. He has overlooked, however, the beauti- ful demonstration of DorEty? that gravity is the cause of anisocotyly in Cerato- zomia; nor among the anisophyllous gymnosperms does he mention this and other cases in cycads. The general conclusion is that anisophylly, which is very much more general than is commonly thought, cannot be said to be due in nature directly to the ' Figpor, W., Die Erscheinung der Anisophyllie: eine morphologisch physiol” gische Studie. 8yo. pp. vilit+175. figs. 23. fls.7. Franz Deuticke: Leipzig un Wien. 1909. 2 Dorety, HELEN A., The seedling of Ceratozamia. Bot. GAZETTE 46:3°5- 1908. 306 1909] CURRENT LITERATURE 307 meet factors of whose value we are ignorant. That ignorance needs emphasis. To say—‘‘anisophylly is to be looked upon as a special case of anisomorphy, by which we understand, with WresNER who proposed this term, that fundamental property of living substance in consequence of which the different organs (in our case the foliage leaves) have the power, each according to its position toward the horizontal or toward the parent axis, to assume different typical forms’”’— is merely to cloak ignorance with pedantry.—C. R. B. Desert vegetation A very fitting celebration of the fifth anniversary of the establishment of the Desert Laboratory was the publication of a treatise on North American deserts the number of valuable contributions emanating from Tucson. e contribution here considered includes some of the matter that made up the body of the first” Teport on our desert region by CoviLLE and MacDovucat in 1903 (Publication 6), but the great amount of new material, based on subsequent explorations and on the investigations at Tucson, made imperative the publication of a general treatise of this sort. An account is given first of the earlier investigations of the institution and the development of the department of botanical research, especial attention being directed to problems of long continuance, such as the study of the revegeta- tion of the Salton Basin and experiments on acclimatization. Nearly half of the work is devoted to a general account of the various desert regions of North America, including the various Mexican deserts, the northern sage-brush deserts, the Mohave desert and Death Valley, the Sonoran and Colorado deserts. Then follows a sketch of the geological features of the region about Tucson, by Professor Og BLAKE, territorial geologist of Arizona; herein is contained an account of the soils, including the caliche, an interesting calcareous formation arising through deposition from waters percolating upward. An interesting sketch is given of the seasonal changes in the aspect of the vegetation about Tucson. The early winter rains stimulate the development of a number of winter perennials and annuals. In the spring and early summer the aspect is controlled by more X€rophytic spinose and succulent forms, notably the cacti. The humid mid- summer, like the winter, is characterized by a number of forms stimulated to development by the greater moisture. ‘The treatise closes with a consideration of ‘emperatures of plants in the desert (it being suggested that the great difference between air and soil temperatures is likely to be of significance), the water relations of desert plants, soil relations of desert plants, conditions contributory to deserts, and some general remarks on the formation and extent of deserts and the influ- “nce of the desert on life. This treatise will be a sine qua non for all ecological Workers, since it brings together what is known concerning our deserts, taking *MacDoucat, D, T., Botanical features of North American deserts. Carnegie Institut : ‘stitution of Washington, Publication 99. 19 308 BOTANICAL GAZETTE [OCTOBER account of collateral information as well as the researches at the Desert Laboratory.—HeEnry C. Cow es. Animal galls A prodigious amount of work is represented by the two ponderous volumes of Hovarp, devoted to the galls, produced by animals, which have been found upon European plants, including those of the Mediterranean basin.* Few botanists, we imagine, are aware of the extent of what now really ranks as a special branch of biological science, cecidology, which has its own journal, Marcellia, and is awakening the interest of both botanists and entomologists. this monumental work Hovarp describes 6239 zoocecidia, produced by 1466 species of animals, on 2299 species of plants. Of the animal gall-producers the most important are the Insecta, of the families Curculionidae (Coleoptera), Cynipidae (Hymenoptera), Cecidomyidae and Muscidae > (Diptera), Aphididae i i Nema Rotifera are represented by one species each. Of the plants 68 are cryptogams, 35 gymnosperms, 173 monocotyls, and 2053 dicotyls. A large number of the galls are illustrated by original figures and some copies, ~ both external and sectional views being given when necessary to show structure. The part of the plant deformed is indicated; the gall is described tersely, with compact and inconspicuous bibliographical notations; the specific name of the There is a full bibliography, arranged alphabetically by authors; an index to the animals named, preceded by a tabular view of the genera, classified by families and orders; and an index of the plants by genera and species It is not often one sees a scientific work involving jaeh multifarious detail planned so carefully and carried out so consistently and successfully. Herein the publishers doubtless deserve praise for active cooperation. It would be difficult to find a flaw in either plan or execution. Since no extensive studies on the cecidia of this country have been made, these volumes, the most thorough, comprehensive, and accurate that have yet appeared in any country, will doubtless serve for many years in the preliminary work that needs to be done on our own galls. They must certainly be most useful, and it is to be hoped that with such a guide, more of our younger biologists will take up the study with vigor.—C. R. B. a Darwin memorial volume Among the numerous publications in commemoration of the centenary of the birth of CHartes Darwsn and of the fiftieth anniversary of the publication of 4 Hovarp, C., Les zoocécidies des plantes d’Europe et du bassin de la — ranée. 2 vols. 8vo. pp. 1248. figs. 1365. pl. 2. portraits 4. Paris: A. Hermann Fils. 1909. 45 fr. D i ' 1909] CURRENT LITERATURE 309 _ the Origin of species, no one seems more appropriate and satisfactory than the volume issued by the Cambridge Philosophical Society and the Syndics of the University Press.s It consists of twenty-eight essays written by those who are most competent to present the various appropriate topics. The result is to illustrate the far-reaching influence of Darwrn’s work and also the present atti- tude of investigators toward Darwinism. Some of the essayists have restricted themselves to DARWIN’s own work; while others have outlined the progress of more recent research, which has been the direct outcome of his work. Two photographs of DARWIN are reproduced, one made in 1854, and the other in 1880; while a reproduced etching gives a most interesting view of the study at Down. To review such a collection of essays briefly is impossible, but the subjects and the authors will indicate the general contents to those interested in evolutionary octrine. Ten of the twenty-eight essays are of interest to botanists. The series most appropriately begins with an introductory letter by Sir JoserH D. Hooker, for forty years the intimate friend and correspondent of Darwin. The ten essays of botanical interest are as follows: ‘‘Darwin’s predecessors,” by J. Artur THomson (15 pp.); ‘The selection theory,” by Aucust WEIs- MANN (48 pp.); ‘‘Variation,” by Huco pE Vries (19 pp-); “Heredity and varia- tion in modern lights,” by W. BATESON (17 pp.); “The minute structure of cells in relation to heredity,” by EDUARD STRASBURGER (Io pp.); “The palaeonto- logical record. II. Plants,’ by D. H. Scorr (23 pp-); “The influence of environ- ment on the forms of plants,’ by GEORG KLEBS (24 PP); “Geographical dis- tribution of plants,” by W. T. THISELTON-DYER (21 pp.); “‘Darwin’s work on the movement of plants,” by Francis DARWIN (16 pp.); “The biology of flowers,” by K. Gorse (23 pp.) : All of these essays address themselves primarily to the intelligent public rather than to investigators, and therefore they are in a sense popular statemen and not contributions to knowledge. In spite of this, they are very interestin to investigators, for personal and recent points of view are in evidence throughout, and the whole group of related topics is brought together in clear and compact & form.—J. M MINOR NOTICES Recent publications from the National Herbarium.—A. S. HitcHcock (Contr. U. S. Nat. Herb. 12:183-258. 1909) has issued a “Catalogue of the grasses of Cuba.” The work is based primarily on material in the herbarium of the Experi- ment Station at Santiago de las Vegas, Cuba. Sixty-six genera are recorded and to these are referred 225 species of which ro are indicated as new; one new genus (Reimarochloa) is proposed. More than one-half (36) of the genera here listed ee Tepresented by single species. The author gives carefully prepared keys leading to the genus and species and also cites numerous exsiccatae, thus greatly s Darwin and modern science. Essays edited by A. C. SEWARD. 8vo. pp. xvii+ 59°. Cambridge: The University Press. 1909. $5.00. er 310 BOTANICAL GAZETTE [OCTOBER enhancing the practical value of the publication.—J. N. Rose (ibid. 259-302) has published the sixth paper in his “Studies of Mexican and Central American plants.” About 75 species are described as new, and several transfers have been made. Three new genera (Pelozia, Pseudolopezia, and Jehlia) of the Onagraceae are briefly characterized. The text is supplemented by numerous illustrations.— P. C. STANDLEY (2bid. 303-389. pls. 28-43) publishes an interesting systematic * treatment of the Allioniaceae, dealing chiefly with those of the United States. The author recognizes 16 genera, describes about 50 species and some 20 so-called sub-species as new to science; three of the genera enumerated are new, namely _ Anulocaulis, Commicarpus, and Hesperonia. Through an apparent oversight the genus Commicarpus either has been omitted from the key to the genera or confused with Senkenbergia.—N. L. Brirron and J. N. Rose (ibid. 391, 392. pls. 44, 45) propose a new genus (Thompsonella) of the Crassulaceae; the genus is represented by two Mexican species. The type of the genus is Echeveria minuti- flora Rose.—J. N. Rose (ibid. 393-409. pls. 46-59) describes 10 new species of flowering plants chiefly from Mexico and the southwest, including also a new genus (Conzatlia) of the Leguminosae, and makes critical notes on species previously published.—N. L. Brirron and J. N. Rose (ibid. 413-437. pls. 61-76); in an article entitled ‘The genus Cereus and its allies in North America,’’ have recorded 24 genera, of which 15 are designated as new. Of the 131 species enumerated 12 are described as new, 77 form new combinations, and 19 are of doubtful generic relationship. The new genera proposed are as follows: A cantho- cereus, Bergerocactus, Heliocereus, Hylocereus, Lemaireocereus, Leptocereus, Lophocereus, Nyctocereus, Pachycereus, Peniocereus, Rathbunia, Selenicereus, Weberocereus, Werckleocereus, and Wilcoxia.—J. N. Rose (ibid. 439, 44° pls. 77-81) describes and illustrates 5 new species of Crassulaceae from Mexico.— J. M. Coutrerand J. N. Rose (ibid. 441-451. pls. 82, 83) have issued a “Supple- ment to the monograph of the North American Umbelliferae” in which the authors include descriptions of 6 new species; two new genera are also proposed, namely, Ligusticella and Orumbella.—W. R. Maxon (ibid. 411. pl. 60) describes and illustrates a new species of Asplenium from China; and (ibid. 13: 1-43. pls. 1-9- 1909) in continuation of a series of articles begun in an earlier volume of this ‘journal has published results of further studies of tropical American ferns. In this paper, the second of the series, the author describes 16 species of ferns and 2 species of Lycopodium from Mexico and Central America, and also presents a “Revision of the West Indian species of Polystichum”’ in which 19 species are recognized, 4 being hitherto undescribed.—J. M. GREENMAN. A garden book.—A lover of flowers will find pleasure and inspiration in 4 charming book entitled A little Maryland garden by Heten Asué Havys.° She writes in a most interesting and pleasantly intimate way of her experienc starting a flower garden, of her successes and failures, and of the great satisfaction 8. es in 6 Hays, HELEN AsHE, A little Maryland garden. 12 mo. pp.——: PM New York: G. P. Putnam’s Sons. 1909. $1. 1909] CURRENT LITERATURE 311 one derives from a garden which is klein, aber mein. The book is beautifully illustrated with eight halftones in color by ZvutmaA Dr L. STEELE, and would be a pleasing gift book, as well as an excellent reference book for an amateur who may feel, with the author, that “at least it is better to have tried and failed, than not even to have made the attempt.’’ The author, however, was evidently success- ful and shows an intimate knowledge of garden life. The nature sketches are pleasing, and the whole book is written in a very happy vein, to which its attractive form is appropriate——Mary H. Frost. Hymenomycetes of the Chicago region.—The Natural History Survey of the Chicago Academy of Sciences has begun the publication of a descriptive catalogue of the higher fungi of the Chicago area. The first part, containing the Hymenomycetes by Morratt, has just appeared.? It is well printed and the plates are halftones from excellent photographs. The keys to genera and species should make determination comparatively simple, but the key to genera would be far more convenient if the page numbers were inserted. The “Chicago area” means Cook and Dupage counties, with portions of Will County, Ill., and Lake County, Ind., including about 1800 square’ miles. From this area 371 species of Hymenomycetes are reported, representing 79 genera, the distribution by families being as follows: Agaricaceae, 46 gen., 211 spp.; Polyporaceae, 15 gen., 78 spp.; Hydnaceae, 5 gen., 25 spp.; Thelephoraceae, 8 gen., 41 spp.; Clavari- aceae, 2 gen., 12 spp.; Tremellaceae, 3 gen., 4 spp.—J. Indian woods and their uses.—The Imperial Forest Research Institute of India has begun the publication of a series of memoirs, the first number of which deals with Indian woods and their uses.$ It is a bulky quarto volume of nearly 500 Pages, dealing wih 554 species. This is only a fraction of the total number ot Indian woody species, which is said to be about 5000 and rather more than half of them trees. The first part contains a list of the purposes for which woods are employed and the woods used for each, while in the second part these woods are described. There is an index to English and trade names (9 pp.), and also a Surprisingly extensive one (202 pp.) to vernacular names.—J. M. C. The flora of central and southern Congo.—Another fascicle® of this important taxonomic work has been issued recently under the able editorship of Professor Eu. De WitpeMAN. The present fascicle contains a list of Mycetes prepared by the late Professor P. HeENntncs, also a list of fungi by H. and P. Sypow, the Pteridophyta have been elaborated by Dr. H. Curist and the Embryophyta by Dr. DE Witpeman. Nearly one hundred new species and several varieties are ee 7Morratr, W. S., The higher fungi of the Chicago region. Part I. The Hymenomycetes. Chicago Acad. Sci. Nat. Hist. Surv. Bull. 721-156. pls. I-24. 1909- 8 Troup, R. S., Indian woods and their uses. Indian Forest Memoirs 1: No. 1. 4to. pp. 273 + cexvii. 1909. 9Dr Witpeman, Em., Flore du Bas- et du Moyen-Congo. Ann. Mus. Congo. Botanique, Sér. V. Tome iii. fasc. 1. pp. 147. pls. 27. Brussels. 1909- 312 BOTANICAL GAZETTE [octoBER — here published, and the text is supplemented by twenty-seven full-page illustra- tions.—J. M. GREENMAN. Handbook of deciduous trees.—The ninth part'® of ScHNEIDER’s Handbook (the fourth section of the second volume) has followed the preceding one?" with great promptness. As already noted. it presents descriptions of the species of angiospermous trees, native or under cultivation in central Europe, and is illus- trated freely. The present part begins with Tilia and ends with Rhododendron. —j. M. C. ; NOTES FOR STUDENTS Morphology of Tumboa:—Three years ago PEARSON published? the results of his investigation of Tumboa (Welwitschia) from material obtained in one day’s - collecting. A second expedition to Damaraland was made possible and material was collected during January and February of 1907, the results of the investiga tion of which are now published.73 The additional stages thus secured have put our knowledge of this most interesting plant upon a fairly substantial basis, and Pearson is to be thanked for his persistent enthusiasm in securing this difficult material. An outline of what seem to be the most significant new results is as follows: The staminate and ovulate strobili are often produced in great profusion and their occurrence below the single pair of leaves is frequent. Pollination is mainly effected by a hemipterous insect (Odontopus), the pollen being received by a nectar drop on the top of the projecting micropylar tube. The pollen grains frequently germinate in the micropyle at some distance from the tip of the nucellus, pollination. The generative cell passes into the tube, where its nucleus divides, the binucleate cell either remaining undivided or forming two male cells. The tube nucleus begins to break down before fertilization and eventually disappears. The most critical and puzzling structure of Tumboa, however, is the embryo sac. Megaspores and embryo sacs are often present in the pith region of the axis of the ovulate strobilus, so that the cauline origin of the ovule is clear. A single megaspore mother cell is organized and a single megaspore functions. The female gametophyte begins with free nuclear division and no vacuolation, and successive simultaneous divisions occur until there are approximately 1024 free and crowded nuclei. Elongation of the sac then occurs, chiefly in its micropylar +¢ SCHNEIDER, C. K., Illustriertes Handbuch der Laubholzkunde. Neunte Liefer- — (vierte Lieferung des zweiten Bandes). Imp. 8vo. pp. 367-496. figs. 249-. 328. ustav Fischer. tg09. M 4. *« Bor. GAZETTE 472415. 1909. 12 Pearson, H. H. W., Some observations on Welwitschia mirabilis escapee: Phil. Trans. Roy. Soc. London B 198:26s-304. pls. 18-22. 1906. Review in Bot. GAZETTE 42:67. 1906. 13 __—, Further observations on Welwitschia. Phil, Trans. Roy. Soc. London B 200:331~-402. pls. 22-30. 1909. 1909] _ CURRENT LITERATURE 313 fourth, so that the outer nuclei are more widely separated than the rest. These more scattered nuclei are sexually functional, while the more crowded ones in the inner three-fourths of the sac give rise to the endosperm. Incomplete wall- formation occurs, dividing the sac into irregular and multinucleate compartments, those of the upper fourth usually containing not more than six nuclei, while those of the lower three-fourths contain twelve or more nuclei. ‘The outer multinucleate cells develop tubular prolongations (prothallial tubes) into the nucellus, into which the nuclei and most of the cytoplasm pass. Occasionally these sexual nuclei fuse within the prothallial tube. In the multinucleate cells of the inner three-fourths of the sac the nuclei seldom divide, but all fuse, forming uni- nucleate cells. This endosperm, consisting of uninucleate cells whose nuclei are formed by the fusion of what the author regards as potential gametes, he calls a trophophyte, to distinugish it from both gametophyte and sporophyte, and says that it “differs fundamentally from the prothallus of the lower gymnosperms,” a statement which will have to be amended in a way that will make the proposed name seem unnecessary. When connection is established between the tip of a pollen tube and of a prothallial tube, “the leading female nucleus enters the generative cell within which fertilization occurs,” which is certainly a remarkable performance. n embryo-formation, the fertilized egg elongates to form a proembryonal tube, toward the tip of which the nucleus moves and divides, when a tip cell is cut off by an ingrowing wall, just as in Gnetum. The tubular cell of the pro- embryo continues to elongate, while the tip cell develops the embryo, which consists of about sixty cells when its tip reaches the endosperm. The author enters into a somewhat extended discussion of the general bear- ings of the facts he has uncovered, a discussion which will be considered in another connection.—J. M. C. Mechanism of photeolic movements.—LEPESCHKIN, whose investigations of turgor mechanisms have been already extensive and important, has added a study of the mechanism concerned in the so-called sleep movements of leaves, which he be suggested. Long sinceS I proposed for the sleep movements the term photeolic movements, avoiding thus the false implications of sleep, nyctitropic, and photo- Rastic.) Without referring to the divergent views of various authors on which his ae ‘4 LepEscHKin, W. W., Zur Kenntnis des Mechanismus der photonastischen Variationsbewegungen und der Einwirkung des Beleuchtungswechsels auf die Plas- mamembran. Beih. Bot. Centralbl. 242308-356- 1909. Preliminary paper: Zur Kenntnis des Variationsbewegungen. Ber. Deutsch. Bot. Gesells. 26a:724-735- 1908. x HEALD, F. D., Contribution to the comparative histology of pulvini and the Tesulting photeolic movements. Bor. GAZETTE 197480. 1894. . 314 BOTANICAL GAZETTE [OCTOBER conclusions bear, an attempt i le here to state clearly and tersely LEPESCHKIN’S conception of the various processes concerned in the movements by motor organs. A change in illumination induces a change in the permeability of the plasma membranes for solutes; this results in an alteration of the turgor pressure, which of course alters the volume of the opposed halves of the motor organ, and alters it in the same fashion, though not at the same rate or to the same extent. Darkening reduces permeability, and consequently increases the turgor; lighting has the opposite effect. The result of the inequalities of these changes in turgor is a curvature of the pulvinus. After this has appeared, diffusion of the solutes begins toward the convex side, where the concentration is now lowest in consequence of the absorption of water in this half and its expulsion on the concave side; this leads to the restoration of the normal concentration of sap and a resultant heighten- ing of turgor on the convex side, with a corresponding lowering of it on the other, thus intensifying the curvature. Alteration of permeability by changes of illumina- tion is not peculiar to motor organs, but occurs also in epidermal cells of Trades- cantia and in Spirogyra, where it is proportionally as great, but cannot have the Same consequences.t® Of the two movements ordinarily induced by change in illumination, the rise or fall of the leaf and the reverse, only the primary movement is produced as described; the reverse movement is rather of the nature of an after- effect of the primary curvature. Geotropic curvatures of the motor organs are explicable on the same principles. The’ physiological dorsiventrality of the motor organs is due to the normal direction of gravity. Plants which raise their leaves on darkening, have their photeolic movements intensified by being inverted, while those that drop their leaves have them reversed by inversion.—C. R. B Seedling structure of gymnosperms.—The third paper under this title, by Hive and Frarne,'7 treats of the Ginkgoales and Cycadales, and contains the usual valuable coordination of scattered results. Under the three heads of cotyledons, transition region, and root, the following conclusions are reached: otyledons.—The cotyledons, generally two in number, are hypogeal and are persistently imbedded in the gametophyte; they are frequently unequal and there is a marked tendency to form lobes, and in some cases there is a short basal tube; among Cycadales they are more or less closely fused by their ventral sur- faces; stomata are generally present, secretory cells and canals are common, and the vascular bundles are mesarch or exarch in varying degrees; the number of undles in each cotyledon varies from one to eight, in all cases being greater in the central region than near the base or tip. Transition region —The transition phenomena occur rapidly, so that most of the hypocotyl shows root structure; Ginkgo differs from the observed cycads = that it has a rotation of the protoxylem of the cotyledonary traces; in Ginkgo each cotyledonary bundle gives rise to two poles of the root (except in the case of +6 See also TRONDLE, p. 318. '7 Hitt, T. G., anp Frame, E. ve, On the seedling structure of gymnosperms. II. Annals of Botany 23:433-458. pl. 30. 1909. oe er eee Se Oke a” eS Sg ee Ree ils r é : 2 1909] CURRENT LITERATURE 315 three cotyledons, when the root is triarch); among cycads the cotyledonary bundles are not of equal value in the production of root structure, and even simi- larly situated bundles vary in the same species; among the cycads the cotyledonary bundles fuse with the plumular traces and ultimately form a central cylinder of variable structure. Root.—In Ginkgo there may be an addition of protoxylem elements after the root structure has been organized; in Stangeria the primary root may branch dichotomously; after the initial root structure has been attained, the number of poles may be increased at lower levels. The paper closes with a very useful table showing the variation in the number of bundles in the base of the cotyledons of the fourteen species discussed, and also the relation of this number to the number of poles in the root structure.—J. M. C Adaptation in fossil plants.—In his presidential address'* at the anniversary meeting (May 24) of the Linnean Society, Scorr took occasion to outline the evidence for adaptation from fossil plants, which naturally dealt chiefly with the anatomical structures of those ancient vascular plants which he has done so much to elucidate. No one is more competent to state the facts in reference to ancient plants, but the conclusions do not seem to be irresistible. In substance they are as follows: (1) at all known stages in the history of plants there has been a thoroughly efficient degree of adaptation to the conditions existing at each period; (2) the characters of plants always having been as highly adaptive as they are now, natural selection appears to afford the only key to evolution which we possess at present; (3) the paleontological record reveals only a relatively short section of the whole evolution of plants, during which there has not been any very marked advance in organization, except in cases where the conditions have become more complex, as illustrated by the floral adaptations of angiosperms; (4) the simple forms of the present flora are reduced rather than primitive, but such reduction may have set in often at a relatively early stage of evolution, and is therefore consistent with a considerable degree of antiquity in the reduced forms. These broad statements, quite apart from their application to certain views of adaptation, contain much wholesome truth for those who imagine that the pale- ontological record, as we know it, represents a continuous succession of “‘higher and higher” plants, for it is becoming increasingly evident that very highly organized plants existed at the very beginning of our record.—J. M. C. Morphology of Penaeaceae._STEPHENS published a preliminary account*® of his studies among the Penaeaceae which was noticed in this journal,*° There has | how appeared the full account with illustrations,2? so that the morphological ities ‘8 Scort, D. H., Presidential address before Linn. Soc., 1909- pp. 15- ‘9 STEPHENS, E. L., A preliminary note on the embryo sac of certain Penaeaceae. Annals of Botany 22:329. 1908. 0 Bor. Sects 45:365- 1908. s, E. L., The = sac and embryo of certain Penaeaceae. Annals 4 Siaas 2 23: ae ‘pls. 25, 26. 1909. 316 BOTANICAL GAZETTE [ocTOBER features of this small shrubby group, restricted to the southwestern region of Cape Colony, are fairly before us. Three of the five genera were investigated (Sarco- colla, Penaea, and Brachysiphon), suitable material of the other two (Endonema and Glischrocolla) not being available. _ {he morphological characters of the three genera examined are the same, so that one account can serve for all: The megaspore mother cell produces four nuclei, usually tetrahedrally arranged, and these migrate to the periphery of the mbryo sac, where each gives rise to a group of four nuclei. Three of the nuclei of each group are organized into cells which resemble an egg-apparatus, while the four remaining free nuclei fuse in the center of the sac to form the primary endosperm nucleus, which after fertilization forms a parietal layer of nuclei, walls appearing much later. The embryo has no suspensor, appearing first as a spher- — ical mass of cells, which elongates as the tissues are differentiated and the growing points are organized. This seems clearly an illustration of the formation of an embryo sac by the cooperation of four megaspores, in this case the product of each megaspore remaining remarkably distinct.—J. M. C. Embryo sac of Pandanus.—A preliminary note?? under this title has already been referred to in this journal.?3 The fuller account, with plates, has now been published.2+ Pandanus has long been regarded as a promising primitive mono- cotyledon, and its investigation is most timely. The general results are as follows: the archesporial cell (presumably solitary) cuts off a parietal cell which gives rise to several layers of cells separating the epidermis from the megaspore mother cell; the mother cell divides transversely into two daughter cells, the inner one of which directly produces the embryo sac, while the outer one divides anticlinally; ¢ first division within the sac (the second reduction division) results in two polar nuclei; the micropylar nucleus divides, and there is no division of the daughter nuclei, nor is there usually any differentiation into egg and synergid; the antipodal nucleus gives rise to twelve nuclei, whether by simultaneous division or not was not determined; in the most advanced stages secured no nuclear fusion was observed, all fourteen nuclei remaining quite separate. The author still maintains that the embryo sac of Pandanus is a more ancient type than the ordinary eight-nucleate sac of angiosperms, and that it represents @ new type, “‘with its nearest analogue in Peperomia.”? It remains to investigate the fertilization stages of this interesting embryo sac, to determine whether the four- teen-nucleate condition really is the fertilization stage.—J. M. C. 22 CAMPBELL, D. H., The embryo sac of Pandanus. Preliminary note. Annals of Botany 22:330. 1908. 23 Bot. GAZETTE 45:364. 1908. *4 CAMPBELL, D. H., The embryo sac of Pandanus. Bull. Torr. Bot. Club 36: 205-220. pls. 16, 17. 1909. 1909] CURRENT LITERATURE 317 The new flora of Krakatau.—Under this title CaAmpBrtt?5 has published an interesting account of a visit to the island of Krakatau, which was “efficiently sterilized” in August 1883, the hot ashes and pumice completely covering the island to an average depth of 30™. The nearest land is an island rokm distant, on which the vegetation was largely destroyed; while Java and Sumatra are 35 and 45km distant. TReruB visited the island in 1886 and 1897, and it was examined again in 1905 and 1906. By 1886, three years after the catastrophe, a considerable number of plants had been established, the ferns predominating in species (11) ment of higher vegetation, the blackish slimy films of species of Oscillatoria coating the surface of the ashes. In 1897, while there were almost no trees, most of the island was covered by vegetation, 62 species of vascular plants being recorded (12 pteridophytes, 50 seed plants), and the ferns stil) predominating in the number of individuals. In the present flora 137 species have been recorded, representing all the principal groups; the ferns are no longer predominant, and the — vegetation is rapidly encroaching toward the center of the island. There remarkable paucity of bryophytes, only two mosses and one Anthoceros having been recorded.—J. M. C. Mechanism of anthers.—ScHNEIDER, having investigated the tulip carefully, objects*® to the conclusions of STEINBRINCK that the rupture of anthers is due to the cohesion of the diminishing water with Gees in 2 te cel ae In we fisen he would distinguish the mechanics of t! valves, and of their subsequent rolling and unrolling. In Tulipa he finds the frst Tupture due to the pressure of the growing pollen mass—an explanation already more than a century old. He does not enlighten us as to the remaining processes; Possibly be are treated in an earlier paper which we have not seen.”7 replies at some length,’ in the usual lively polemic style of our Teutonic friends. Though talipes were out of bloom before SCHNEIDER’s article came to his attention, his preserved material even furnishes some arguments, which are further supported by an examination of the behavior of a large number of plants of other genera. The only one in which STEINBRINCK is willing to admit that anything but cohesion mechanism plays a part, even in the first opening of the valves, is the rye. In this anther “another strong tissue tension Must cooperate, because the broad cleft remains open when one throws the anther : *S CamMPBeLL, D. H., The new flora of Krakatau. Amer. Nat. 43:449-460. wg *° ScuNeweR, J. M., Zur ersten und zweiten Hauptfrage der Antherenmechanik. Ber, ersten Bot. Gesells. 27: 196-201. 1909 » Der Oeffnungsmechanismus ae Tulipanthere. Altstatten, 1908. augur Di Dissectutons. ) D TEINBRINCK, C., Ueber den ersten Oceana ane bei Antheren. Ber. ay Bot. Gesells, 2°73 300-312. figs. 7. 1909. 318 BOTANICAL GAZETTE [OCTOBER at once into water.” ‘The first rupture in this case is an explosive one, which scatters some of the pollen, and cannot be due to the cause assigned by SCHNEIDER. R. B. Mesostrobus, a new genus of Carboniferous lycopods.—WaTSON”? has described the strobilus of a new lycopod from the Lower Coal Measures of Lancashire. It resembles Lepidostrobus, but the sporangium is only attached to the distal half of the horizontal portion of the sporophyll, and the somewhat larger ligule is set in a deep pit. A characteristic point of view is illustrated by the following quotation: ‘“Lepidostrobus would be derived from a cone having sporophylls of this type” (Bothrodendron mundum, etc.) “on the adoption of an ~ arboreal habit by the heterosporous lycopods, because radial elongation of the Sporangium is the most economical way of increasing the number of spores pro- duced, a necessity for a large tree. If this elongation takes place in the part of the sporophyll between the axis and the insertion of the sporangium, we arrive at a condition much like that of Spencerites, and from that condition we can pass through Mesostrobus to Lepidostrobus.”—J. M. C Heating of leaves.—It has been known that the evolution of heat may be demonstrated in living plants by using seedlings and flowers, but leaves have not been considered favorable material for this experiment. MoriscH has now shown3° that in many cases 3-5*s of leaves, placed in a basket and packed in “excelsior,”? show a rise in temperature amounting to 20-45° C. within 12-24 ours. The leaves are usually killed thereby, and after a fall a second rise of than the first. The first evolution of heat he ascribes to the respiration of the leaves, while the second is due to the rapid development of microorganisms. The experiment is simple and worthy a place in the laboratory practice—C. R. B. Osmotic pressure and permeability.—TRONDLE records another example of what has been observed by others, namely, change in the permeability of the protoplast according to the conditions of lighting and temperature. His Lge liminary reports™ concerns the leaves of Tilia cordata and Buxus sempervirens rotundtjolia; in the former both palisade and spongy parenchyma, in the latter only the palisade being investigated. He reports also the high values of 20-26A for the osmotic pressure as determined by plasmolysis. It is to be remembered that plasmolytic studies, such as these, in many of which NaCl was used, are of 20 Watson, D. M. S., On Mesostrobus, a new genus of lycopodiaceous cones footy the Lower Coal Measures, with a note on the systematic position of Spencerites- Annals of Botany 23:379-3098. pl. 27. 19009. 3° Mouiscu, H., Ueber hochgradige Selbsterwirmung lebender Laubblatter. Bot. Zeit. 66 : 211-233. 1908. ; 3: TRONDLE, A., Permeabilititsiinderung und osmotischer Druck in den assiml- lierender Zellen des Laubblittes. Ber. Deutsch. Bot. Gesells. 27:71-78. 1909- RS ee ae RENE EOE MENS eb eT eS fae TEM eee eee oem es ery 1909] CURRENT LITERATURE 319 questionable validity in the light of OsteRHovtT’s researches in this line.3?— Anatomy of the ovule of Myrica.—Miss KersHAw:% has investigated the ovule of Myrica Gale, and has discovered that in all of the morphological features itis an ordinary angiosperm, with its solitary megaspore mother cell, linear tetrad, eight-nucleate embryo sac, and porogamy. The following anatomical features, Owever, are worthy of mention: the nucellus is not only completely free from the single integument but is also distinctly stalked within it; vascular strands (eight or nine in number) traverse the integument, without branching, almost to the apex of the ovule. These two features of the ovule are usually regarded as primitive, belonging to the ancient gymnosperms rather than to angiosperms.— oom. C, . Phototropism of roots.—LINSBAUER and VOUK, after overcoming many experimental difficulties, have found3+ that the roots of Raphanus sativus and Sinapis alba, which have been credited with being only negatively phototropic, Teact positively or negatively according to the intensity of the light. Roots of the ormer in moist air turn toward light of about 8 candles, while in water they are much less sensitive, no very certain curvatures being obtained until the light was increased to 400 c.p. Sinapis in water, on the contrary, gave the best positive response at o.2 c.p., and decided negative curvatures at 0.64 ¢.p. These results Support the M@LLER-OLTMANNS theory of phototropism.—C. R. B. Dispersal of seeds by ants.—Werss%5 has concluded that the gorse (Ulex) and the broom (Sarothamnus) should be included among myrmecochorous plants, along with Chelidonium, Viola, etc. He finds that the seeds have a brightly colored caruncle containing oily food material and resembling in structure and contents the elaiosomes (of SERNANDER) of other myrmecochorous plants; that ants are particularly attracted by the oil-containing caruncle, and can and will carry about the seeds of gorse; and that the rectilinear distribution of gorse bushes along actual or disused paths or roadways is only paralleled by the distri- bution of such plants as the celandine along ant-runs.—J. M. C. Anatomy of Gleichenia. —BoopLE and Hitry*° have investigated the vascular Structure of Gleichenia, a genus interesting on account of its protostelic species. — % Bor. Gazetre 46: 53-55. 1908. Be Kkisuiw Eos Mav, The structure and development of the ovule of Myrica Gale. Annals of Botany 23:353-362. pl. 24. 1909. SBAUER, K., anD Vouk, V., Zur Kenntnis des Heliotropismus der Wurzeln. ch. Bot. Gesells. 27:151-156. 1909. _ °*5 Weiss, F. F., The dispersal of the seeds of the gorse and the broom by ants. New Phytol. 8:81 34 LIN Ber. Deuts —89. Igo9. a * Boopte, L. A., AND Hixey, W. E., On the vascular structure of some species of leichenia, Annals of Botany 23:419-432. pl. 29. 1909. 320 3 BOTANICAL GAZETTE - [octoBER G. pectinata was especially studied, whose rhizome BooDLE3’ had discovered to be solenostelic. This has now been confirmed, solenostely with leaf gaps being found. It is concluded that Eugleichenia represents a series of reduction forms from the Mertensia type (represented by G. flabellata), and that Mertensia includes the most primitive species as well as the most advanced (G. fore in which a solenostelic structure has been derived from a protostelic.—J. M. C. . Ovule of Julianiaceae.—Miss KrrsHaw?* sees in the integumental vascular strands and free nucleus of this recently established Mexican family a suggestion of relationship between Juliania and Juglans, and especially in the association of this structure in both genera with the outgrowth at the base of the ovule known as the obturator. The suggested connection with Anacardiaceae is confirmed by the integumental vascular strands of Mangifera, but in that genus there is no indication of an obturator.—J. M. C Chlorophyll in evergreens.—Miss CAcitie STEIN reports%® that crude chloro- phyll (i.e., all the pigments) increases in amount with the season, and from February to March far more than from March to May; from that time on it seems about constant. The chlorophyll proper increases likewise and decidedly more than the xanthophyll. This, she suggests, may be due to the conversion of the xanthophyll into oa ee but Kout’s experiments strongly antagonize such an explanation.—C. R. B Stock and scion.—At a meeting of the Botanical Society of France last March GRIFFON discussed the results of his numerous experiments in grafting during 1908,4° and declared that, whatever the plants employed (Solanaceae, Legu- minosae, Compositae), and whether the graft was simple or mixed, there was 10 trace of asexual hybridization, but further confirmation of the specific independence of the stock and scion.—C. R. B An abnormal Funaria.—Drxon*™ describes a plant of Funaria hygrometrica from Tonduff having the perigonial leaves fringed by a double row of protuberant and more or less flask-shaped cells which are supposed to function as reservoirs of water oC to the paraphyses for keeping the antheridia well supplied. =e R. B 37 Boones L. A., On the anatomy of the Gleicheniaceae. Annals of Bae - 15:703- Igor 38 Ceasar E. M., Note on the relationship of the Julianiaceae. Annals of Botany 23 :336, 337. 1909 39 STEIN, CACILIE, ine zur Kenntnis der Enstehung des Chlorophy llpigmentes in den Blattern immergriiner Koniferen. Oesterr. Bot. Zeits. 59:231-245, 262-269: 1909 4° GRIFFON, E., Troisitme série de recherches sur la greffe ai plantes herbacées. Bull. Soc. Bot. France §6:203-210. pis. 3, 4. 1909 4 sien H. N., A remarkable form of PES hygrometrica. Bryologist 12+ seis - pl. 5. 1909. No. 5 November 909 Editors: JOHN M. COULTER and CHARLES R. BARNES CONTENTS ‘done Fungus Parasites of Algae : ay ad gcEs : { Cy on in Synchytrium a ; a3 "Robert F. - Griggs | George B. Bsn Croley of Cutleria and fazerey ! ie , : Shigeo “f - aes at eto Se oe = ' The University of Chi azo CHICAGO and NEW YORE ys ‘William ‘Wesley and Son, London : a es ‘S ete oe) ; 3 = The Botanical Gazette - @ Montbly Journal Embracing all Departments of Botanical Science .” Joun M. CouLTER and CHARLEs R. BARNEs, with the aoa of other members of the botanical staff of the University of Chic Issued November 15, 1909 . XLVI CONTENTS FOR NOVEMBER 1909 No. 5 ME FUNGUS PARASITES OF ALGAE (WITH SEVEN FIGURES). George F. Atkinson - ~ 22 g2t ro IS IN SYNCHYTRIUM (wirn PLaTEs xvi-xvil). Robert F. Griggs - - - - 339 BPeNCE OF ELECTRICITY ON MICROORGANISMS (wiTH Two FIGURES). George £. : és - is i = J fe = a os <3 * “ = im OGY OF CUTLERIA AND AGLAOZONIA. Cone ees FROM THE geen Botanica, LaporarTory 129. Shigéo Yamanouchi 386 FER ARTICLES OXYGEN PRESSURE AND THE GERMINATION OF XANTHIUM rca CONTRIBUTIONS FROM 4£ HULL BoranicaL LaporaTory 130. Chas. A. Shull - ‘ ‘3 ¢' - 387 ENT alae TURE OOK REVIEWS - Gs : - : ; = z ae AN AMERICAN MEMORIAL TO DARWIN. REPORT OF AMERICAN BREEDERS’ ASSOCIATION. = FLORAL BIOLOGY a _ urvor NOTICES eS ee ee ee ee ee a NOTES’FOR STUDENTS - & = é “ Z 5 “ - - - - - 395 1 Gazette i is published monthly. The subscription price is $7.00 per year; the price cents. 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A table ae see routings © cost of additional separat an order blank which accompanies the proof; a copy will be sent on request. i md August 21, 1895, at the Post-Office at Chicago, as second-class matter. under Act of Congress March 3, 1879. a VOLUME XLVIII NUMBER 5 BOTANICAL GAZETTE NOVEMBER 1909 SOME FUNGUS PARASITES OF ALGAE" GEORGE F. ATKINSON (WITH EIGHT FIGURES) About twelve years ago I was giving considerable attention to the study of the parasites of the algae in the vicinity of Ithaca, N. Y. At that time I hoped that the investigations might eventuate in a Monograph of the Chytridiales of the Cayuga Lake basin. The Pressure of other investigations has almost completely interrupted these studies. Because of our limited knowledge of the occurrence and habits of these interesting fungi in North America, it has seemed to me desirable that the observations already made should be recorded, In the hope that this may stimulate a greater interest in these plants. As a result of the studies three papers have already been published. An extended paper on the genus Harpochytrium in the United States Was published in 1903,? a summary of which later appeared in the Journal of mycology in 1904.3 A short note on the interesting behavior of the zoospores of Rhizophidium globosum while escaping from the Zoosporangium was published in 1894.4 This behavior related to the habit of their sensing or feeling the exit opening in the sporangium, which they do by means of pseudopod-like extensions of the proto- Plasm in different directions, after having come to rest on the inside of the zoosporangial wall. In case they happen to come to rest close by the exit they “feel” it by one of the pseudopods, and slide out. ‘ Contribution from the Department of Botany, Cornell University, No. 133. * ATKINSON, G. F., The genus Harpochytrium in the United States. Ann. Myc. 1:479-so2. pl. Io. 1903. *-———., Note on the genus Harpochytrium. Jour. Myc. 10:3-8- pl. 72. 1904- é +++, Intelligence manifested by the swarm-spores of Rhizophidium globosum. OT. Gazetre 192503, 504. 1894. 321 322 BOTANICAL GAZETTE [NOVEMBER In case they are distant from the exit, not finding it they round up into the motile zoospore form again and swarm around in the zoospo- rangium for a time, and coming to rest make another trial. It is evident that when the zoosporangium is filled with the zoospores the latter will escape quite rapidly for a time because so many of them are crowded successively against the exit. As the num- bers diminish there is greater freedom for swarming. The zoospores then swarm around and around in great circles Fic. t.—Rhizophidium globosum(A.Br.) inside the wall of the zoospo- eae A Ste Plant, eee after rangium, now and then coming Renae BS tae cee to rest and feeling around for the mature plant ready to form zoospores; exit. This same behavior has C zoospores escaping; D much smaller been observed in the case of a plants. . a number of other species. In addition to this a quite remarkable phenomenon was observed in the case of another species, Rhizophidium brevipes, which will be described below. In the presentation of these observations I shall make no attempt to arrange the genera in any natural order of relationship, this matter being reserved for a future work. Since a number of species of Rhizophidium were studied I will begin with this genus. RHIZOPHIDIUM BREVIPES This was collected in a pool beyond Forest Home, N. Y., 4 little more than one mile from Ithaca. It was attached to the wall of a fruiting cell of Spirogyra varians. The zoosporangium is oval with a small apical papilla. The wall shows two distinct layers, an outer rather thick one and an inner thin one. _At the time of the maturity of the zoospores the papilla of the outer layer becomes gelatinized at the apex, forming a minute opening about 4 » in diameter. One very characteristic feature of this species is the very rudi- mentary condition of the rhizoids. The very slender branched rhizoids so characteristic of R. globosum and other species appeat e awe 1909] ATKINSON—FUNGUS PARASITES OF ALGAE 323 be absent. The penetration tube of the zoospore forms a short stalk, _ which projects but a short distance within the cavity of the host cell. This rudimentary condition of the rhizoids recalls that of Harpochy- trium hedenii Wille, though in the latter it penetrates only the outer lamella of the wall and flattens out in the form of a disk in the middle lamella, or merely pene- trates a thin layer of slime on the host and flattens out on the outer _ wall (ATKINSON 1903). This _ penetration tube serves also as _ the absorbent organ for such food _ as the plant obtains from the 4 fluids within the gametangium of _ the host surrounding its zygo- spore. The zoosporangium measures 21-24 “, while the zoo- Spores are about 3 » in diam- eter, with a single cilium and a Fic. 2.—Rhizophidium brevipes Atk. A mature zoosporangium crowded with zoospores, outer layer of wall at exit pore dissolving, inner layer projecting as a papilla before the rupture, plants attached to a gametangium of Spirogyra contain- ing zygospores; B zoo i C two zoospores, unable to escape by exit pore, have germinated and are attempting : Prominent oil drop. The species was first observed _ Mma cell preparation which was : made on April 24, 1895, at about _ 4%.M. The zoosporangium was _ mature and the protoplasm finely granular. In the course of half an si hour from the time of the first observation, the granules began to _ 4iTange themselves in numerous small groups, the beginning of the formation of the zoospores. Very soon these began to disappear and _ Were gradually replaced by a prominent oil drop for each group of Stanules. Each oil drop was surrounded by a hyaline mass of homo- 8&neous protoplasm. The preparation was watched for the greater : part of the time from 4 p. M. until 6 P. M., and fresh water was fre- 7 quently drawn in, in order to hasten the development and maturity Of the zoospores. At this time it appeared that the zoospores would _ hot become mature under an hour, and the preparation was placed q ‘na moist chamber until 7 p.m. It was then examined and fresh _ Water added. The apical portion of the outer wall was dissolved; in the apex of the tube; D same showing how the zoospores retreated from the first tubes and after swarming around for the second time attempted to escape again by the germ tubes. - 324 BOTANICAL GAZETTE [NOVEMBER soon the inner wall at this point became ruptured, and precisely at 7 P.M. the zoospores began their escape. The number of zoospores was very large and they were packed so tightly in the zoosporangium that it was impossible for them to make other than slight amoeboid movements. Those at the apex slowly moved through the opening one or two at a time, so that the number could be readily counted. In passing through the opening the zoospore puts forth a stout hyaline projection which feels and leads the way, and then the body slowly moves through. On the outside, at the mouth of the zoosporangium, each zoospore rests for a short time, during which a few plastic movements are exhibited; then it rounds off and darts away. When 50 or 60 zoospores had made their escape in this way the space in the zoosporangium was not so crowded, and a few of those at the center began active swarming movements, while those at the periphery of the sporangium were quiet or only exhibited plastic movements, and those nearest the opening continued to escape in the manner described. This continued until there were very few still within the zoosporangium. The remainder of the zoospores were all swarming, and at times some of them would come to rest on the side of the wall, put out by amoeboid movement a short pseudo- podium, and feel evidently for the opening. Not finding it they would swarm around within the zoosporangium again, and again come to rest, maneuver for the opening, and on finding it escape. This manner of finding the opening is the same as that described for R. globosum (ATKINSON 1894), but as the opening is larger than in that species, the body of the zoospore does not become constricted at the passaze. At 7:18 p.m. all but four of the zoospores had made their escape, and in four minutes more two of these had escaped, leaving two still within the zoosporangium. ‘These were watched for an hour longer, and they divided the time in swarming and feeling for the exit, but were unable to escape; though several times they located themselves directly at the opening, they seemed to be insen- sible of it. The preparation was placed in the moist chamber and left for the night. On the following morning both of the zoospores were found located on one side of the zoosporangium and each had germinated. Ig09] ATKINSON—FUNGUS PARASITES OF ALGAE 325 _ The slender germ tube, having penetrated the wall of the zoospo- _ Ttangium, extended ina tortuous course for a distance of 15-20. The _ preparation was examined several times during the day. Since one of the zoospores was located not far from the wall of the spirogyra, it was hoped that the thread would find the cell and enter it, inasmuch __ as it was pointed in that direction. The preparation was left in this condition during another night, the slender tube of the zoospore __ hearest the spirogyra cell not yet having reached it. On the following a Morning the preparation was examined again, and I was surprised to 5 find that one of the zoospores was on the other side of the zoospo- Tangium. Close examination showed that both had moved during the night. Not being able to find any suitable nourishment, the proto- _ plasm in each germinating cell had migrated back from the inclosing _ Membrane into the zoosporangium, formed a zoospore, and had _ Passed through a second swarming period. Then coming to rest _ 4gain they had germinated, the germ tube of each having again _ enetrated the wall of the sporangium and formed a slender tube a 15-20 long. The preparation was kept for a day longer, but the _ Zoospores did not form again. This behavior of the zoospores is quite interesting, since it mani- fests not only a sort of “ingenuity” in the attempt to escape from the Z0osporangium, but, what is more important, the tendency, under _ ©értain conditions of existence which prevent the zoospore from _ Seeking a host cell by the normal planetic method, to migrate in the form of a true mycelial tube, which is quite different from the very q delicate slender absorbent rhizoids normally developed from the germ __ tube in other species of the genus. Rhizophidium brevipes, n. sp.—Zoosporangia oval, 21-24 u in diameter, with 4 papilla at the apex, in which the exit pore is formed. Rhizoidal apparatus very rudimentary, consisting of the short, blunt, unbranched entrance tube Of the Zoospore, which projects but a very short distance beyond the inner : in diameter. = On walls of gametangia of Spirogyra varians in which zygospores are formed. _ Vicinity of Ithaca, N. Y. Zoosporangiis ovatis, apici uno, brevi, papilliformi ostiolo, basi, uno brevi, ga — tubulo. Zoosporis ovoidiis, 3 # latis, una guttula hyalina et uno cilio _ Praeditis, _ lamella of the wall of the host. Zoospores oval with an oil drop, uniciliate, 3 4 326 BOTANICAL GAZETTE [NOVEMBER RHIZOPHIDIUM SPHAEROCARPUM Rhizidium sphaerocarpum Zopf, Nova Acta Leop.-Carol. Deutsch. Akad. 47:202. pl. 19.. figs. 16-27. 1884. Rhizophidium sphaerocarpum A. Fischer, Rabenh. Krypt. Flora Deutschl. Oesterr. u. Schweiz 2 Aufl. 4:95. 1892 What I have taken to be this species occurred in abundance on threads of Mougeotia parvula collected in a gutter on Thompson St., Ithaca, N. Y., April 7, 1895. The zoosporangia are oval in form and vary considerably in size, the larger ones measuring 16-18X 18-20 #, while the smaller ones are about 1oX11 ¢. They occur singly or in groups of two to four, the smaller ones more commonly in groups and the larger ones rarely so. The rhizoids are very much reduced, consisting of a few very short branches from the short entrance tube. The wall of the zoosporangium consists of two lamellae, an outer stout lamella and a thin inner membrane. This is very well seen in the dehiscence of the zoosporangia. At maturity the apex of the outer wall of the zoosporangium dissolves, forming a large circular opening for the exit of the zoospores. Through this the inner membrane projects in the form of a short broad papilla by the swelling of the epiplasm. The final rupture of this membrane sets the zoospores free, and the large opening permits their rapid escape. The exit pore measures 5—6 » in diameter in the larger forms, and in the smaller ones is proportionately larger, being 4-6 w in diameter, some of the smaller zoosporangia appearing like cups when open. The zoospores are oval, possess a long cilium and a prominent oil globule, and measure 1.5-2 in diameter. In germination, if the germ tube 1s directed toward the wall of the host cell, it penetrates the wall, and then the zoospore enlarges to the size of the mature plant, becoming the zoosporangium. If, however, as sometimes happens, the germ tube is directed away from the wall, or along its surface, it may gTOW to a considerable distance, sometimes reaching a length of 30 - The zoosporangia sometimes grow so as to appear attached by their side instead of by their base, and the opening is then at the side (fig. 3; C). In nearly all of the larger specimens (which may prove to be a different species) the effect on the host cell was quite remarkable. The host cell not only becomes considerably larger near the middle, ! 3 SE, eA PS eee eee ee Pee ST) ee a ee ee ee ee Ne ene es eee | er eine ps eee verse 1909] ATKINSON—FUNGUS PARASITES OF ALGAE 327 but is very much elongated. Frequently at the middle it is not much larger, while on each side an enlargement occurs (fig. 3, D,’G). The _ stimulus which causes the increase in the length and size of the cell also increases the development of the chromatophore. When this influence ceases the chromatophore begins to degenerate, the color Fic. 3.—Rhizophidium s showing entrance of germinating zoospores, and mature plant with Spo a Plants also attached to the host; C mature empty zoosporangia, showing one with the Penetration tube on the side; D mature plant, large form, showing hypertrophy and Curving of host cell ; £ mature plant with escaping zoospores, showing strongly curved host cell; FG showing hypertrophy of host cell; H—M different stages in the opening of the 2oosporangium and escape of the zoospores; A-G original; H—M after Zopr. fades, the structure breaks down, and the processes of dissolution Separate it into small particles with the pyrenoids more distinct, all Coalescing into an amorphous mass, which gradually flows toward the Middle of the cell where the sporangium is located. This may be due Partly to the fact that the cell of the host is larger at that point, as well 328 BOTANICAL GAZETTE [NOVEMBER | as to an influence which the parasite exerts upon it, for it is possible that the crowding of the chromatophores from each side toward the middle may cause the two enlargements near the middle with the constriction between them (jig. 3, G). Not only does the influence of the parasite excite these changes in the host cell, but it also causes the cell to become more or less strongly arched at the point of insertion of the sporangium, the sporangium being in the concavity of the arched thread. This effect has only been noted in connection with the larger forms, except where the smaller ones are several in a group, and here the curving of the thread is slight in comparison with that which exists in the case of the larger sporangia. Zopr (I. c.) does not mention any similar hypertrophy of the host cell caused by this species, nor is it shown in his illustrations. He figures the plant on Spirogyra. A. FiscHeEr (/.c.) reports it on various filamentous Con- jugatae and Oedogoniaceae, but does not mention any hypertrophy of the host. Germinating zoospores have been observed in this species in which the germ tube may become directed away from the host and develop a mycelial tube 15-20 » in length. RHIZOPHIDIUM MINUTUM This species was collected on Spirogyra varians in a pool beyond Forest Home, N. Y. (about one mile from Ithaca), April 23, 1895. a It frequently accompanies Lagenidium, but Re _ also occurs independently of it. The ane rangia are sessile, very small, obpyriform oF _ Fic. 4.—Rhizophidium flask-shaped.-. Thus the species belongs to the sae nha oehaahe longata section of the genus. The zoosporan and aotepceeal: ’ gia are 5-6 # in diameter. At the base are a few slender rhizoidal threads which extend 4 short distance in the host cell content. The form of the 2005? rangium thus presents a broad and prominent apical papilla, the end of which becomes gelatinized at maturity of the zoospores, forming a circular exit pore. The zoospores are few in number, two to four in the cases observed. They measure 2. 5 » in diameter, and are provided with one cilium and a prominent oil drop. Rhizophidium minutum, n. sp.—Zoosporangia obpyriform or flask-shaped, broadly papillate, 5-6 # in ae sessile with a few slender rhizoidal filaments 3 i Igog] ATKINSON—FUNGUS PARASITES OF ALGAE 329 at the base in the host cell. Apex opening by a single pore. Zoospores two to four in a zoosporangium, oval, uniciliate, with a single oil drop, 2.5 « in diameter. On Spirogyra varians in the vicinity of Ithaca, N. Y. Zoosporangiis obpyriformibus, 5—6 latis, apice una lata papilla, basi fila- mentis brevibus radiciformibus. Zoosporis ovoidis, 2.5 #, una guttula hyalina et cilio simplici attenuato praeditis. LAGENIDIUM RABENHORSTIS This species was first found in a species of Spirogyra in a stream of slow-running water in the valley south of the city of Ithaca. Ithas since been found in various species and appears to be quite common. The fungus attacks the vegetative cells and those just about to con- jugate. The zoospore enters the cell wall by a small perforation, the slender entrance tube growing usually nearly to the center of the host cell, where it enlarges to the size of the vegetative thread of the parasite. The general course of the threads is parallel with the axis of the spirogyra cell, though frequently tortuous and curved, with here and there short branches. The threads are usually stout, varying in diameter from 3 to 8. At the ends of the cell of the host they curve around and frequently extend back to the other end, one to three and four threads thus lying in a single cell. The protoplasm possesses numerous highly refringent granules and there are also vacuoles at short distances. In other cases the thread may be strongly curved, or even coiled at various points within the end of the cell. The chromatophores of the spirogyra are broken down and usually adhere to the threads of the fungus here and there, giving portions of them a green appearance in the early stages, and later a greenish brown as the chlorophyll becomes more and more disorganized. All traces of the chlorophyll at length disappear, and the fungus, lying in a disorganized mass of transparent protoplasm, is then seen distinctly throughout its entire length. In other cases the fungus thread may be permanently soiled by the brownish matter of the disorganized chlorophyll. The exit tubes are developed from the ends of the threads, or from the ends of the short lateral branches, or from the side of the main 0 * Zopr, W., Ueber einen neuen parasitischen Phycomyceten aus der Abtheilung der sporeen. Bot. Verein Prov. Brandenburg 20:77—80. 1878. See also, Zur Kennt- 330 BOTANICAL GAZETTE [NOVEMBER thread itself, in the latter cases usually arising from the outer con- vexity of a curved portion of the thread. The exit tube is about 2» in diameter and projects but a little way outside of the wall of the host. The tube develops quite rapidly. In observations on cell cultures where I have been watching for the migration of the protoplasm through the exit tube, cos ones have been observed to develop in two to four hours time. The end of the tube becomes gelati- nized and the protoplasm moves in a quite rapid stream through the tube, the small spherical mass of protoplasm at the mouth of the tube growing rapidly in size until all the protoplasm has passed through, which takes only a few seconds. In a few moments Wiha See i rotary motion begins, sow at Walker cae prosporangia, which are fSt. Soon the constriction of the sections of the thallus; B zoospores form- mass occurs in lines over the sur- ing at the apex of the exit tube; C zoo- face, in such a way as to divide or and small particles separated from he ua teee inta portio ns ac- cording to the size of the mass and the number of the zoospores to be formed. In this species I have not observed any inclosing membrane, nor any evidence that such a membrane exists, though Zopr (i. c., p. 149, 1884) describes and figures one. The constriction goes on from the surface toward the center, and soon the cilia are developed, their slow waving aiding in the slow but perceptible oscillatory motion of the mass. Plastic movements of the mass and the developing individuals also accompany the other movements. When division has become nearly complete, small portions frequently become constricted from the ends of the ovate to reniform individuals, the constriction becoming deeper and deeper, until in many cases the small portion becomes separate from the larger mass (jig. 5, C). These can be seen to be separate from the larger ones by the gliding motion of the zoospores over each other, and over the smaller bodies. The movements become more and more active, occasionally one zoospore pulling strongly in 1909] ATKINSON—FUNGUS PARASITES OF ALGAE 331 one direction and separating itself from the group by several milli- meters; then it is drawn back again to its fellows as if by a retractile cord; then another will separate in the same manner, only soon to be drawn back again. This pulling away and returning becomes more and more accentuated each time, until finally one of the zoospores makes its permanent escape, leaving the others to struggle still for freedom. One by one, or two or more at a time, they escape in this manner and whirl away. This mode of escape would indicate that there is no inclosing membrane. Before the escape of the zoospores, in cases where small portions of the zoospores have become separated, they may fuse or conjugate with the large ones again, but whether with the same one from which they were separated or with a different one could not be determined, since the gliding and rotary movement of the individuals and the mass would prevent absolutely the following of the separate ones through their various evolutions. DEBary® (p. 37, 1881) first observed a separation of portions of the protoplasm and their fusion again with the parent masses in the formation of the oospores of the Saprolegniaceae, and it has since been observed in the oospores by Hartoc? (p. 24) and Humpurey’ (p. go). It was first observed in the zoospores of the Saprolegniaceae by Rothert® (1887, also p. 322, 1890; see also HaRroG, J. c.). When fusion did not take place before the zoospores made their escape from the group, the smaller portions would not then fuse with the larger ones, even if they came by acci- _ dent in contact with them, so far as I was able to observe. In other Cases the small portions of protoplasm might become partially separated from the larger ones, and the zoospores escape with a minute appendage attached either at one of the extremities or upon - °DEBary, A., Untersuchungen iiber die Peronosporeen und Saprolegnieen und os Grundlagen eines natiirlichen Systems der Pilze. Beitr. Morph. u. Phys. der Pilze 431-145. pls. 1-6. 188r. 7 Hartoc, M. M., Some problems of reproduction. Quart. Jour. Micr. Sci. 33: ee 1892 . REY, J. E., The Saprolegniaceae of the United States, with notes on other Species, ies Am. Phil. S Soc. 17:63-148. pls. 14-20. 1893. ® RotHert, W., Die Entwickelung der Sporangien bei den Saprolognieen. Beitr. Biol. Pf. 5:2 291-349. pl. IO. 1 ne This paper first appeared in Polish in the Pro- ceedings of the Cracow Academ 17t 1887. 332 BOTANICAL GAZETTE [NOVEMBER the more convex side, where it gave the zoospore the appearance of being a “hunch back.”” Such zoospores would perform very curious evolutions in their vain efforts to throw off the offending appendix, but in no case observed did this separation take place after the zoo- spores had separated from the group at the mouth of the exit tube. The number of zoospores from a single zoosporangium is 2-8, as stated above, or possibly a few more in some cases, the number depending upon the size of the sporangium. In one case observed, where the zoospores seemed to be rather sluggish in their development and the movements not so active, the form was not so pronouncedly reniform, but more nearly oval, and after separating very little active movement took place, the individuals soon rounding off as they do when ready to germinate. Two such zoospores soon came in.contact and immediately fused into a larger one, the fusion taking place in about ten seconds. The further fate of these zoospores was not followed. This fusion may be due to the peculiar conditions of environment, perhaps to the want of fresh water in the limits of the cell culture. From some observations made on the developing zoospores under similar conditions, it appears possible that it may be due to the variations of tension existing between the individuals and the original mass of protoplasm, the tension of the entire mass being directed toward keeping the mass intact and the tension of the individuals tending to separate the masses into smaller individuals. Two cases were observed which had progressed to some extent toward the formation of the zoospores. In one cas¢ there were two zoospores forming and in the other case four zoospores were forming from the spherical protoplasmic mass, which shad collected at the end of the exit tube after passing from the sporang!um- In each case the zoospores were about one-third formed. The preparation had been in the cell culture for two days and the water had been replenished a few times, as it had partially evaporated, by running fresh water under the cover from the edge, the cell cultures being made simply between the cover glass and the glass slip and net in a ring-cell, or vAN TreGHEM cell. The oxygen thus accessible to the organism was very small, though this did not seem to hinder the development during study, if water were added every few moments, as would be necessary when the preparation was not protected in @ 1909] ATKINSON—FUNGUS PARASITES OF ALGAE 333 moist chamber. While these two developing groups of zoospores were under observation, the water, which had not been changed for some time, slowly evaporated, so that a portion of it was removed from under the cover. At this time it was noted that the dividing protoplasmic mass, where there were two forming zoospores, was fusing again, and soon the mass was spherical, with no sign of the division which up to this time was quite marked, and showed all the phenomena of movement and formation of cilia which accompany the normal development of the zoospores, except that the movements were not so active. Very soon also the four forming zoospores in the other group were fusing and the movements had likewise ceased. The fusion in this case also continued until there was no trace of the forming zoospores, the mass was again spherical, and movement had ceased. Thinking this might be due to the want of fresh water, some was quickly run under the cover glass, and the observation was renewed. The smaller protoplasmic mass burst on the absorption of the water, So great was the tension, but the larger one soon began slow rotary movement again and the constrictions appeared a second time, indi- cating the formation of four zoospores. This time the division pro- ceeded, accompanied by all the phenomena of the formation of the zoospores noted in the normal cases, until the zoospores were com- plete and whirled away. This would suggest that there were two opposing tensions in the formation of the zoospores, one individual and under normal condi- tions the stronger, and the other belonging to the mass and the weaker. When the conditions favorable for the formation of the zoospores ceased, the individual tension lessened to such a degree that it was lower than that of the mass, and the separating smaller portions were drawn together again in the common larger mass. These two pposing tensions might possibly explain the peculiar behavior of the zoospores when they still remain closely associated in the group, how partially separating and again coming close together, continu- ing this process of coquetting until the individual tension is strong fnough to free them, in the case of those where there does not seem to be any inclosing membrane. The tension of the entire mass May possibly be somewhat similar to the force called adelphotaxy 334 BOTANICAL GAZEITE ~*~ [NOVEMBER by Hartoc’® (p. 216) in the case of the escaping zoospores of Achlya and Aphanomyces. In some of the cell cultures in which numerous zoospores of Lagenidium were developing, there were several sun animalcules (Actinophrys sol). Some of these were so full of zoospores which they had caught, that they appeared to be a rounded collection of the zoospores, the convex outer portion of the zoospore only showing, and the entire surface of the Actinophrys appearing like a piece of mosaic made up of these unfortunate creatures. The delicate arms — or rays of the Actinophrys radiated for a distance of 20-30 #, and in a large number of cases which were observed, whenever a zoospore passed within reach of these rays, no matter how swiftly it was moving, it was suddenly paralyzed and halted; then the reniform shape gradually became spherical and it was slowly drawn by “invisible threads” to the body of the Actinophrys and slowly wedged its way between those which had preceded it. LAGENIDIUM AMERICANUM Another species of Lagenidium, which seems to differ from any described, was found in various species of Spirogyra (5. varians, S. calospora, and S. insignis) collected in a pool beyond Forest Home, April 11, 1895. It is parasitic in the zygospores and conjugating cells of the spirogyras, but has not been observed to develop in the vegetative cells... The vegetative phase of the fungus consists of strongly curved and coiled tubes, 4-8 » in diameter, the size varying so that the contour and diameter of the threads is very irregular. It is profusely branched, and has also numerous short branches. It frequently fills the zygospores so completely that the individual course of the thread can be followed for only a short distance. At maturity — the tube, as in the other species, is separated into segments of various lengths by the development of cross-walls, forming the zoosporang!a. Frequently there is a constriction at the septum. Numerous Z200Sp0" rangia are developed in a single zygospore. The exit tubes are slender, measuring about 2 « in diameter, and of variable length according to the direction in which they emerge from the zygospore and the wall — o Hartoc, M. M., Recent researches on the Saprolegnieae. Annals of Botany 2:201-216. 1888. ee ee Se Ee Se Be tkaiwa Lar <9 ee a ee Un Te ae Tee, CTT oe 1909] ATKINSON—FUNGUS PARASITES OF ALGAE 335 of its parent cell. If the zoosporangium is located at the periphery of the zygospore near the middle, the tube is quite short. In the case of the zoosporangia which are located at the ends of the zygospores, the length of the exit tube is considerably longer, even when it is directed from the start perpendicularly to the wall of the parent spirogyra cell. In many cases, however, the exit tube from the zoosporangia which lie at the ends of the zygospore starts out nearly parallel with axis of the spirogyra cell, or at some angle between this and the perpendicu- lar. In such cases:the exit tube may be very long and tortuous, frequently passing into the adjacent spirogyra cell and finally emer- _ ging through the wall of the latter. The protoplasm, with numerous small highly refringent granules and a number of vacuoles, presents practically the same appearance as in the case of the other species. It passes ina rapid stream through the exit tube and collects in an irregularly spherical mass at the extremity, from which in some cases it soon becomes free and floats to a short distance. In ten minutes from the passage slight rotary movements begin, the mass turning a short distance in one direction, and then in a moment in the other direction, the movement becoming faster and repeated at shorter intervals. a In some cases the cilia can be seen as delicate rays, even before the simultaneous constriction of the mass begins and they are slowly lashing. In other cases they are observed very soon after the con- striction of the mass begins which outlines the surfacgof the individual Zoospores. No inclosing membrane was observed, and it seems possible that it should exist if the cilia can extend for such a distance ‘Tom the mass. As the division proceeds the reniform shape of the Individuals becomes more and more pronounced, and the movements “come more and more violent. The individuals divide the time in a quivering motion followed by the oscillatory movements and the gliding over one another until they are apparently separate, now ®ne pulling off a short distance, then returning, and so on, until they make their escape one after another or several at a time. After “sparating from the group, movement in space is rather slow, as if they were uncertain how to use the freedom gained. The individual scillates and glides around in various curves, then becomes nearly Stationary and quivers for a moment; then, one end remaining 336 BOTANICAL GAZETTE [NOVEMBER stationary, the other executes in succession several jerks or nods as if striking at something; then it enters upon another series of evolutions. After a short time thus engaged, the activity of the zoospore increases, the field covered by its evolutions becomes larger, and it is lost from the field of the microscope. In some cases which were timed the zoospores were separate in 25~30 minutes from the time the ~ Fic. 6.—Lagenidium americanum Atk. in zygosp f Spirog) A, Bsome empty and some mature prosporangia; C from one prosporangium the protoplasm has just issued from the exit tube; D plasma sphere or zoosporangium proper free from the exit tube and floating in water; E formation of cilia where a zoosporangium is swim- ming around as a multiciliat ; F, G different stages in formation and separation of zoospores, the groups swimming around like a pandorina colony; H mature and separate zoospore. protoplasm passed from the exit tube. In those cases where the - plasma vesicle at the end of the tube becomes free and floats away, — the cilia develop on its surface, and it at first presents the appearance of a multiciliate spore. Later the divisions occur in such a way aS to leave two cilia with each forming zoospore, and the colony then resembles a pandorina colony. Lagenidium americanum, n. sp.—Plant body in the form of irregular tubes, much branched, curved, and of unequal diameter, confined within the host zygote, 3-8 4 in diameter. Exit tubes slender, short, 2 4 in diameter, varying in len but extending a short distance outside of the gametangium wall, of equal diameter from the point where they pierce the wall of the zygote to the outer free end, thus differing from the exit tubes of L. entophytum (Pringsh.) Zopf. Exit tubes arising from the end of hyphae or branches, or from the convex side of curved or enlarged portions. Zoosporangia of varying size, irregular and often branched, formed from segments of the thallus. Plasma sphere at the end of the exit tube often becoming free and floating away (the cilia then forming on the outside of the Me ey ee ee 1909] ATKINSON—FUNGUS PARASITES OF ALGAE 337 sphere), and finally dividing into the individual zoospores, the whole resembling a pandorina colony, but at last the zoospores separating. Zoospores reniform, laterally biciliate, 4-6 5—7 u n zygospores of S$ piri varians, S. insignis, and S. calospora, Ithaca, N. Y. Mycelio inequali, curvato, ramulo irregulare instructo, 3-84 lato. Zoospo- Tangiis irregularibus, saepe ramulosis. Ostiolo tubiformi tenuissimi aequali, 2 lato. Prosporangiis ramulosis sectionibus mycelii formatis. Zoosporangiis vesiculosis, saepe deciduis, ciliis ornatis, ut coenobio Pandorinae natantibus, postremo divisis, zoospores formantibus. Zoosporis fabaeformibus, laterale biciliatis, 465-7 4. Hab. in zygosporis Spirogyrae, Ithaca, N. Y PHLYCTOCHYTRIUM PLANICORNE This genus, Phlyctochytrium Schroeter,*: differs from Rhizo- phidium in the presence of a swelling on the penetration tube, just inside the host cell wall, from which the delicate nutritive rhizoids grow. Phlyctochytrium planicorne has been found quite frequently in company with Lagenidium americanum, in the cells of Spirogyra varians, Be from the pool beyond Forest Home (near Ithaca). The zoosporangium is a little broader than long, measuring 68 m, and is broadest in the middle. At the apex it is provided with four plain dentate Processes around the exit pore. These dentate processes are char- acteristic of one section of the genus (Dentigera ROSEN,'? SCHROETER, 0p. ¢., p. 79). The endophytic bladder-like base of the plant is separated from the epiphytic zoosporangium by a constricted portion at the point where the penetration tube passes through the cell wall of the host. This base is about 3 in diameter, and from it radiate several slender branching threadlike rhizoids. No zoo- Spores have as yet been observed. While it very frequent'y accom- panies Lagenidium, it is by no means confined to the cells affected by the fungus, being found on other cells also. Phlyctochytrium planicorne, n. sp.—Zoosporangium broadly elliptical, 6X8 u, armed at the apex with four plain teeth. Endophytic vesicle globose, 3H in diameter, with several radiating branched slender rhizoids. On cells of § he fo varians, often accompanying Lagenidium americanum, hear Ithaca, N. Y G. 7.—Phlycto- ee planicorne ene J., in ENGLER & PRANTL, Pflanzenfam. 11:78. 1892. *? Rosen, F., Ein Beitrag zur Kenntniss der Chytridiaceen. Beitr. Biol. Pflanzen 45253-266. pls. 13, 14. 1887. 338 BOTANICAL GAZETTE [NOVEMBER Zoosporangio ellipsoideo, 6X8, apice 4 cornuis ornato. Cellula inferiori 3eulata. Hab. in Spirogyra varianti. PHLYCTOCHYTRIUM EQUALE This species inhabits the cells of Spirogyra, having been found in the cells of S. insignis, collected in the pool beyond Forest Home, April 17, 1895. The epiphytic sporangium and the subsporangial endophytic base are about equal in size, being spherical in form and about 6 #in diameter. The mouth of the sporangium appears to have two small teeth, which may be the walls of a short canal. From the base of the subsporangial part of the plant are several branching rhizoid-like threads. Zoospores have not been observed. Fic. 8.— Phlyctochy- trium equale Atk. Phlyctochytrium equale, n. sp.—Zoosporangium globose, sessile, about 6m in diameter. Subsporangil base equal in size, with several long branched rhizoid filaments from its Zoosporangio globoso, seat 6» lato, basi subsporangiali aequalt, rhizoideis filamentibus ramulosis praedito. Hab. in S roe insigne. A few other species have been Spaced but not studied further than for their identification. They are as follows: Lagenidium enecans Zopf (p. 154, 1884), in Stauroneis phoent- centron and Cymbella lanceolatum, in swamps near Freeville, N. Y., May 5, 1 ea ie bulligera (Zopf) Fischer (Rhizidium bulligerum Zopi, P- 195, 1884), in Spirogyra insignis in pool at Forest Home, N.Y.) April 17, 1895. Rhizophidium ampullaceum (A. Br.) Schroeter, on sterile threads of Oedogonium, Freeville, N. Y., May 4, 1895. Ectrogella bacillariacearum Zopf (p. 175, 1884), in diatoms, south end of Cayuga Lake, Ithaca, N. Y. CoRNELL UNIVERSITY MITOSIS IN SYNCHYTRIUM 4 wits SOME OBSERVATIONS ON THE INDIVIDUALITY OF THE CHROMOSOMES: ROBERT F. GRIGGS (WITH PLATES XVI-XVIII) _. The nuclei of Synchytrium decipiens, a leaf parasite of the hog F peanut, were shown in previous papers to be derived very largely by -amitosis. Several sorts of amitosis were observed, two of which, nuclear gemmation and heteroschizis, differ considerably from the “ordinary. process of amitosis. The nuclei derived by these direct _ divisions were shown to be persistent, and some of them were observed : _to divide by mitosis. This with other facts led me to the conclusion 4 “that the nuclei derived by these processes of amitosis are normal, The purpose of the present paper is to describe the mitoses which 4 follow, to correlate them with the amitoses, and to discuss the theo- _ Tetical bearing of the facts thus presented. I would here repeat my acknowledgments to my friend, Professor or. L. STEVENS, of the North Carolina College of Agriculture and _ Mechanic Arts, who furnished the material used in the investigation and gave the suggestions that originally aroused my interest in the _ Problem. The sections were cut 2-10 thick and stained with _ Haidenhain’s iron alum hematoxylin and with anilin safranin and _ gentian violet. c As in coenocytes generally, all the nuclei in a cyst pass into mitosis 3 simultaneously and divide with equal rapidity, so that all of them are very nearly in the same stage throughout. This fact may be utilized for Overcoming one of the most serious obstacles encountered in 2 investigating the cytology of this plant—the difficulty of estimating _ the relative ages of the different structures in the absence of any & ‘Contribution from the Botanical Laboratory of the Ohio State University, ; No. XLIX. 339] [Botanical Gazette, vol. 48 340 BOTANICAL GAZETTE [NOVEMBER indications external to the nuclei themselves—for those cysts which are of critical age usually contain short series of closely connected stages which frequently enable one to assure himself concerning diffi- cult points, such as the formation of the spindle or the origin of the asters. Nuclei of widely different phase in the same cyst are very rare: fig. 5 is a case where the small nuclei in the cyst were still in the vegetative condition while the large nuclei had passed into spirem; fig. 35 shows a case where the small nuclei had reached late anaphase while the large nuclei were still in metaphase; fig. 36 of the previous paper (5) is a case where the reverse was true, the small nuclei being in metaphase while the large ones were in anaphase. It would be a matter of great interest to ascertain the mechanism by which the nuclei are kept in phase. While not throwing much light on the nature of the stimulus, the behavior of newly segmented cysts is interesting in this connection. In such a cyst, long before the walls of the zoosporangia appear, while the segments are still separated from each other only by an exceedingly delicate plasmatic membrane, each nucleus has become entirely independent of the others; and one finds vegetative nuclei, metaphases, and telophases in adjacent seg- ments, showing how slight a separation suffices to establish the com- plete physiological autonomy of the individual nucleus (fig. 33): All of the mitoses of Synchytrium are of the same type. It is true that none of the later nuclei undergo such a shrinkage in volume with its associated peculiarities as occurs preparatory to the primary mitosis (STEVENS 18), but these phenomena are probably due simply to the enormous size of this overgrown nucleus. It may be recalled that similar peculiarities are usually observed in very large nuclei wherever they are found. CHAMBERLAIN (1), for example, was not able to interpret the structures he found in the enormous egg nucleus of Dioon. But aside from these peculiarities of the primary nucleus, the only differences that could be detected were in the size of the spindles, those in the early stages being fairly large, while those in the last mitoses of the sporangium are exceedingly minute (figs. 32-34): In the resting nuclei of Synchytrium the chromatin is all concen trated in a single globular karyosome (jigs. r, 31). Except in those cases where vacuoles have appeared on the removal of the chromatin preparatory to mitosis or nuclear gemmation (fig. 36), the karyosome Pi Ra ai at eS ey aa al a a ie a Sites OAR Sr ei ey) de a Ath ore ll a Rome hes 1909] GRIGGS—MITOSIS IN SYNCHYTRIUM 341 is an entirely irresolvable, deeply colored body, whether stained with hematoxylin or safranin. Besides the karyosome there may be a few deeply staining granules on the nuclear membrane, but there is nothing corresponding to the chromatin reticulum characteristic of the vegetative nuclei of many cells. The only nuclei in which the chromatin approached the condition of a reticulum were located in the degenerating cysts occasionally found. The spirem The early prophases of mitosis consist in the formation of the spirem from this compact karyosome. This is brought about in the most*direct manner possible. The karyosome first separates into a number of irregular chromatin masses (figs. 2, 30); next delicate linin bands appear connecting these granules with the nuclear mem- brane (fig. 3); and along these bands the chromatin granules are distributed over the nuclear cavity, forming the expanded spirem (ig. 4 from the same cyst as fig. 2). Only a portion of the spirems of Synchytrium, however, are destined to pass into mitosis. A large proportion of them undergo nuclear gem- mation or some other form of amitosis. In view of theoretical con- siderations which will be discussed later, it is of the utmost importance to determine whether the spirems of amitosis are of the same nature as those of mitosis, or whether they are different in kind and present only accidentally an optical similarity. In most cases it is easy to distinguish the two sorts by the cysts in which they occur. In those cysts which are in the prophases of mitosis, the nuclei are in general very nearly the same size and evenly spaced off from each other, while in the amitotic cysts there are small nuclei in groups or clusters 4S well as the large spirems. Many such spirems have a strikingly different aspect from the mitotic spirems. They are coarser (jig. 37), the chromatin granules are very much larger, and the linin strands are short and heavy; whereas the mitotic spirems are characterized by linin threads and chromatin granules of various sizes lying side by Side. In the amitotic spirems each of the chromatin granules is evidently simply the karyosome of a small nucleus, for the formation of which the spirem is a preparation. It would thus appear that the two classes of spirems are entirely different from each other, but 342 BOTANICAL GAZETTE [NOVEMBER unfortunately for this view a very large proportion of the amitotic spirems are intermediate, or so closely resemble the mitotic spirems that they can be distinguished from them only by the character of the cyst in which they occur (fig. 41, a, b,c). It seems impossible therefore to determine certainly whether these two classes are distinct or whether they are of the same nature. The origin of the spindle In those cells where the spindle is intranuclear, there seem to be two types of spindle formation. In the first type, which occurs in the ascomycetes (e. g., Phyllactinia, HARPER 8) and brown algae (e.g., Fucus, YAMANOUCHI 21), the centrosomes are permanent organs of the cell and form the spindle by moving around the nucleus so as to include the chromosomes between them, organizing the spindle by the union of those astral rays which penetrate the nucleus in a manner very similar to that prevalent among animals. This process is very conspicuous and has been observed and figured by numerous investigators. In the other type, which occurs in the oomycetes (e. g., Saprolegnia, Davis 3; and Albugo, STEVENS 16), centrosomes are either small or absent in the early stages; to this type the spindles of Synchytrium belong. Here the determination of the origin of the spindle is very difficult. This probably accounts for the fact that very few of those who have figured such mitoses have given a series of figures of the prophases complete enough to throw much light on the formation of the spindle. When first seen, the spindle of Synchytrium, which is thrown directly across the cavity, is not distinguishable by its staining reaction or otherwise from a strand of the spirem (figs. 6-8). It is therefore difficult to be certain just when the spindle appears or what it comes from, but it gives every indication of being differentiated from 4 spirem strand. Very soon, however, it becomes sharply pointed and quite different from the spirem, which now begins to be drawn 1D around its equator (figs. 9, 10). Contraction continues and more definite connections between the chromatin and the spindle fibers are established (jigs. 11, 12). In this condition the spindle often appe@t> bipolar (fig. 9), which emphasizes the similarity of the linin strands and the spindle fibers. By further contraction this much shortened 1909] GRIGGS—MITOSIS IN SYNCHYTRIUM 343 spirem is converted into the four chromosomes of metaphase (figs. 14,15). Very frequently, however, the contraction is so pronounced that the individual chromosomes cannot be made out in the chromatic mass at the equator (jig. 13). Some spindles show nucleoli lying in the nuclear cavity beside the spindle; in others no nucleolus is present. No difference was observed between the spindles with nucleoli and those without; but it was observed that in any given cyst all of the spindles were alike in this respect—either all had nucleoli or all lacked them. In rare cases more than one of these bodies were present. The nucleoli remain beside the spindle till after the daughter nuclei have separated in telophase (figs. 22, 29, 33), when they disappear. As soon as the spindle is formed, the nuclear membrane with the small chromatic granules which are imbedded in it begins to disappear (figs. 10-15), soon leaving the spindle free in the cytoplasm. As is usual with the intranuclear spindles of fungi, the metaphase in which the chromatin is all concentrated at the equator, if we may judge from the frequency with which it is observed, is of long duration. This is in contrast with the mitoses of the higher plants, where good metaphases, far from being the commonest, are observed less fre- quently than other stages. Anaphase and telophase The spherical chromosomes are pulled away from each other in the usual manner by the fibers of the spindle, which are exceedingly heavy (figs. 15,17). In early anaphase, figures stained with anilin safranin and gentian violet show the chromosomes red and the spindle violet but in hematoxylin preparations the chromosomes are difficult to differentiate from the spindle fibers. This difficulty increases in late anaphase until it becomes impossible to distinguish chromatic from achromatic structures, even when stained with the safranin- Violet combination. When the chromosomes pull apart, they remain connected by heavy fibers similar to those by which they were pulled away from each other (fig. 18), which persist long after the chromo- somes become lost in the condensed mass at the poles (jig. 19). These deeply staining fibers are very conspicuous and give a character- istic appearance to side views of anaphases, which somewhat resem- 344 BOTANICAL GAZETTE [NOVEMBER bles the daughter stars formed in mitoses where the chromosomes themselves are elongated. These fibers may be used to determine the chromosome number, since each one of them is connected with a chromosome. This can be done more easily in this stage than in metaphase, because the fibers are larger than the chromosomes and because they spread apart as they separate, sometimes giving views of all four at once, while in any other stage the full number can be seen only from polar view (jig. 16). These radiating bands of fibers are now drawn in, leaving the two poles connected only by a central band (figs. 20, 22), which becomes considerably attenuated as the two chromatic masses move farther and farther apart. The daughter nuclei become separated by distances considerably greater than the original length of the spindle. In moving apart one or both of them frequently swerves from the axis of the spindle, so that the connecting fibers meet at a considerable angle (fig. 33). As was indicated in the paper on the reconstruction of the nucleus (Griccs 4), this habit makes it almost impossible to associate the daughter nuclei in pairs after the wisps of spindle which point to the original position of the equator have disappeared, especially since the wide separation greatly lessens the chances of securing both in the same section. For this reason all figures of stages after this period are drawn from only one of the daughter nuclei. After the spindles have broken in two, the telo- phases are very inconspicuous objects; though they stain deeply, the chromatin is concentrated into so narrow a space that they are practically invisible under any but the highest power (figs. 23, 35)- The aster As previously reported by Stevens, Kusano, and myself, there are no granules, radiations, condensations, or any other indications of the presence of centrosomes at the poles of the spindle during prophase or metaphase. But about the time the two halves of the spindle separate, radiations begin to emanate from the chromatic masses. At first so delicate as to be on the very limit of visibility, the aster rapidly increases in prominence until it becomes exceedingly conspicuous, clearly visible under a magnification of forty or fifty diameters. At first the radiations may appear to emanate from the ——S "Se lo eh we ee is | os ale 1909] GRIGGS—MITOSIS IN SYNCHYTRIUM 345: center of the chromatic mass (figs. 24, 25), but very soon it is evident that the focus is beyond the condensed chromosomes (fig. 24). AS the rays increase in strength the focus is shifted, until there is a considerable interval between the center and the chromatin (jig. 27). In this stage, since the chromatin is condensed to its minimum volume, the aster is so very much more prominent than the chromatin that the latter is likely to be overlooked altogether, making it appear that the cyst has no nuclei, but only asters! The chromatic mass soon enlarges, however, and rounds off into the spherical karyosome of the resting nucleus (figs. 27, 28). Up to this stage the chromatin lies suspended in the cytoreticulum, without any apparent relation to it. The appearance of the karyosome, however, marks the resumption of definite relations of nucleus and cytoplasm in the formation of a vacuole around the chromatin (fig. 28). This vacuole is at first bounded only by the meshes of the cytoplasm, but soon the rays of the aster bend around it and form the heavy nuclear membrane which incloses it (figs. 29, 30), as previously described by KusANno (10) and myself (4). When the nuclear membrane is complete, the aster gradually disappears; the rays first become much more numerous and finer; the center gradually becomes diffuse and stains less deeply (fig. 4); and finally the aster is transformed into a condensation of _ cytoplasm as previously described (figs. 31, 20, 3): During the disappearance of the aster, however, the nucleus usually enters into the prophases of the next division, so that only seldom is 4 cyst found where the nuclei are still in their vegetative condition when the asters are in their last stages. On the other hand, it is not at all unusual to find that the new spindle has already formed, before the aster has disappeared, and in rare cases the anaphase of the suc- ceeding division (fig. 20) may be reached before the old aster is com- pletely gone. The disappearance of the aster probably occupies a Period of somewhat definite length, while the rapidity with which the mitoses succeed each other varies greatly in diferent cysts. 1 Was this lack of correspondence between the cycles of astral and nuclear metamorphoses that made it necessary in the former paper on this subject to state some conclusions provisionally that may now be positively established. 3 From their function of forming the nuclear membrane, the asters 346 BOTANICAL GAZETTE [NOVEMBER of Synchytrium have been named karyodermatoplasts by Kusano (13). Although somewhat long, this term may be useful in alluding to the junction of the asters, but there seem to be certain objections to its use as the name of a structure. First, the structure so desig- nated is so variable that it is difficult to define it. Sometimes the _ aster is single, sometimes double or triple (fig. 2); sometimes it has one clearly defined granule at the focus of the rays; more often there are several such granules more or less eccentrically placed; or there may be none at all. Sometimes there is an elongated band which bears radiations all along its length, like the blepharoplast of a cycad. It is evident that the term karyodermatoplast can be defined only by its function, while such a term should rest on a morphological basis. Second, though the aster, so far as observation has yet indi- cated, serves only to reconstruct the nuclear membrane, that function alone does not seem to the writer adequate to account for its enormous development in Synchytrium. This is more apparent when one recalls the fact that in heteroschizis and nuclear gemmation the membranes of the daughter nuclei are formed without the intervention of any such structure. I have preferred, therefore, in the present discussion to employ the descriptive term aster for the structure in question, without committing myself to its significance. The question of the radiate structures in Synchytrium and their homology is one of very great interest and deserves consideration in a separate paper. The chromosome number Inasmuch as most of the nuclei or their ancestors have been derived | by amitosis, as has been previously shown, the determination of the number of chromosomes in Synchytrium becomes a matter of much more importance than in organisms where the orderly sequence of mitosis has not been interrupted. On this account especial care has been taken to insure accuracy of observation and interpretation. Upward of 500 slides have been used in the study. Altogether several hundred mitotic cysts with many thousands of individual spindles have been observed. Of these only the most favorable were used for basing the conclusions. The location of the cysts containing these most favorable spindles was recorded by vernier readings of the mechanical stage and filed in a card catalogue, so that they could be Be. AP ee” ey 1909] GRIGGS—MITOSIS IN SYNCHYTRIUM 347 reexamined in rapid succession as frequently as desired. The favorable cysts so listed number about fifty; most of them contain several hundred spindles. All of the results obtained were not exactly concordant, but I shall give the observations on which the conclusions were based that the reader may be enabled to judge of their soundness for himself. In all but two of these favorable cysts there were constantly four chromo- somes. In these two, however, the number of chromatin bodies was certainly more than four (fig. 42). But while the chromosomes are all of the same size, some of these bodies were smaller than chromo- somes and had the appearance of masses of chromatin from the late spirem which had not yet fused together into the compact chromo- somes of metaphase. Inasmuch as the spindles were undoubtedly newly formed, this is probably the correct interpretation, especially as there seemed to be in some cases faint wisps of spirem remaining about the equator of the spindle. But whether these supernumerary chromatin bodies are to be explained on some such basis or whether they are actual irregularities in the number of chromosomes, I am of the opinion that they do not seriously weaken the conclusion that the chromosome number is four. Although it is unusual for a Writer to state difficulties of this sort as frankly as has WILSON (20) in his study of Metapodius, seeming discrepancies in the number arising from one cause or another are, I believe, frequently met with in efforts to count chromosomes. In all of the other cysts studied there was no deviation from the Constant number four. On all of the spindles the chromosomes were Placed at angles of about go°, so that two, three, or four of them were Visible, according to the angle of observation (figs. 14-19). In the very much larger number of cysts whose spindles were not favorable €nough to permit exact counting, there were no indications of a different number. It should be noted also that four is an exceedingly “asy number to count, for one can see four without counting them One by one as is necessary for a larger number. In thus maintaining @ Constant number of chromosomes the writer is supported by the only other published accounts of the chromosomes of Synchytrium. TEVENS in his paper on the primary mitosis (18) states (p. 413) that “ they are probably four in number, although we do not assert 348 BOTANICAL GAZETTE [NOVEMBER this with certainty,” and in his second paper he shows spindles with the same number of chromosomes. KuUsANo (10) reports definitely five chromosomes in S. puerariae. The probability that the results thus obtained are accurate is very greatly increased by the fact that in Synchytrium there is no differ- entiation into soma and germ plasm. Every nucleus becomes either directly or through its descendants the nucleus of a spore, which, if successful in entering its host, becomes the large nucleus of a primary cyst. Ifa variation of the chromosome number occurred at any point, it would, on the individuality hypothesis, be perpetuated indefinitely, affecting all the nuclei of later generations; whereas in the higher plants and animals a variation in the somatic nuclei would be lost with the death of the individual organism in which it occurred. It is clear, therefore, that if a variation in the number of chromosomes should occur only once in the repeated direct divisions through which the nuclei of the spores have been derived, it would affect all the nuclei of the next generation. Thus, though the nuclei of the later stages of the parasite are so small that an irregularity in the chromosome number might not be detected, yet in the large nuclei of the succeeding generation it could not escape observation. Amitosis plays $0 important a part in the formation of the nuclei that if chromosome variations occurred in only one per cent. of the direct divisions, the nuclei of the whole parasite would in the course of a few generations become so irregular that it would be impossible to recognize the original number of chromosomes when it did occur. It may also be remarked that an irregular reduction in the number of chromosomes, such as might be expected ‘in the amitoses of a non-sexual organism like Synchytrium, could lead, when repeated in indefinite series, t© only one result—all the nuclei would finally have only one chromo- some. On the individuality of the chromosomes Modern cytology may be almost said to be built around the theory of the individuality of the chromosomes, and certainly no other hypothesis has borne so much fruit in valuable results as this. Without it the complicated process of mitosis would seem to lack significance, and the doubling and reducing of the chromosomes in =a ui a eal tha a 1909] GRIGGS—MITOSIS IN SYNCHYFRIUM 349 fertilization and reduction would be well-nigh meaningless. For its _ support it has had, besides the constancy of the chromosomes in the species, various observations on nuclei which were known to contain either more or less than the normal number of chromosomes. The great difficulty in the way of the theory has always been that the chromosomes apparently lose their individual existence during the vegetative phases of the nucleus. In many cases where the nuclei are rapidly dividing the chromosomes do not, however, entirely lose their individuality between the successive divisions, but divide and reproduce themselves directly from the compact condition of mitosis. These cases have been the evidence by which the vegetative period of the nucleus was bridged over by the individuality hypothesis, for there is an unbroken series of intergradations from this condition to that in which the chromosomes have completely lost their morpho- logical identity, and one would not suppose that nuclei in one condi- tion differed fundamentally from those in the other. Accordingly, basing their statements on observations of nuclei in which the indi- vidual chromosomes could be traced, with more or less certainty, from mitosis to mitosis, several writers have asserted confidently that the individuality of the chromosomes is maintained through all con- ditions of the chromatin, whether visible or not. But the transformations of a set of chromosomes which, after they are once formed, persist and divide are not necessarily equivalent to the formation of a new set from a diffuse reticulum. If the chro- matin reticulum gave rise only to the chromosomes, the analogy might be closer; but when, as frequently happens, large amounts of chro- matin are cast out into the cytoplasm as nucleoli, microsomes, or in Mass, it is evident that the succeeding differentiation of the chromo- somes involves factors different from those entering into the mere transformation of a chromosome which persists intact through what- ver metamorphoses it may pass. This may be illustrated perhaps y comparing the chromosomes to metal rods which remain distinct from each other when cold, but as the temperature approaches the melting point become soft, lose their shape, and partially fuse together, though each retains its distinctness and can be reclaimed unchanged °n cooling. But after they have once melted together, all this is changed, and they can be regained from the homogeneous flux only by 350 BOTANICAL GAZETTE [NOVEMBER making them entirely over again. It seems quite possible that in the diffuse vegetative reticulum the chromosomes are as completely fused as the molten metal, and until we know more than we do now con- cerning the nature of the reticulum, this alternative possibility should be kept before us. The analogy of the molten metal is more suggest- ive in cases like Synchytrium, where the chromatin is partially or completely concentrated in a karyosome from which part or all of the spirem is directly derived. Although cytologists have as a rule paid but little attention to their behavior in mitosis (cf. WAGER 19), such structures are common occurrences in many plants and animals. If we may infer safely, as I believe we may, that the chromosomes of Synchytrium decipiens number constantly four, it becomes a matter of primary interest to determine how that constant number is main- tained in all of the amitoses through which the nuclei pass. It has long been assumed that the principal if not indeed the sole function of the complicated process of mitosis was to insure exactly equal division of the chromatin between the daughter nuclei. In view of the fact, however, that the majority of the nuclei of Synchytrium are derived by some form of amitosis either directly or through their ancestors, and yet maintain the number of their chromosomes con- stant, it is evident that mitosis is not necessary to maintain this number. The possibilities of an exact mechanical division of the chromatin are somewhat different in the different varieties of amitosis. In heteroschizis there occurs a metamorphosis of the nucleus suggestive of that of mitosis. In the loss of the nuclear membrane and the apparent cessation of interaction between the nucleus and the cyto- plasm there may be a pause during which the chromatin is divided granule by granule in such a way that the karyosomes of the daughter nuclei are furnished with exactly equal chromatin content, just as is visibly accomplished by the fission of the chromatin granules or the chromosomes in mitosis. Likewise it is not inconceivable that the karyosome may be divided in a similar manner when it is broken up preparatory to nuclear gemmation, though in this variety of amitosis there is no loss of the nuclear membrane or other indication of a pause in metabolism. An exact equational division of the chromatin under such circum- 1909] GRIGGS—MITOSIS IN SYNCHYTRIUM 351 stances would be something of a novelty, but it would not necessarily involve functions of the chromatin differing fundamentally from some with which we are more familiar. Whenever the chromatin is with- drawn granule by granule from a karyosome (nucleolus) preparatory to mitosis, we must suppose, on the individuality hypothesis, that the granules come out of the nucleus as they went in, properly sorted, so that each granule is taken into that chromosome from which it came. On the assumption of an equational division in heteroschizis and nuclear gemmation, we should have to assume, in addition to this well-known property of the chromatin granules to sort themselves out - from the apparently homogeneous mass of chromatin of the karyo- some, only the further property of reproducing themselves while yet within the karyosome as they ordinarily do in the spirem. This is perhaps not too much to ascribe to the chromatin, but even such an addition to our theory would add a very large field for speculation where the conclusions, with our present methods, could never be checked by observation. But when nuclear gemmation takes place in spirem two alternative Possibilities are presented, the choice between which depends on the nature of the spirem involved. If the spirem is an entirely different Structure from the mitotic spirem, it would be rational to suppose that each small karyosome, i. e., each granule of the spirem in nuclei Such as fig. 37, contains four chromosomes derived by an equational division of the mother karyosome as in the previous cases. But if the amitotic spirem is like the mitotic, the situation is entirely different, for we know from its later history the composition of the mitotic spirem. It contains altogether only four chromosomes, which are arranged serially, and any small part will contain chromatin from only one chromosome, if a small part of such a spirem is extruded and forms an independent nucleus. Therefore, it is evident that ts chromatin is derived not from all four but from only one chromo- Some. It is then a matter of great importance to determine the con- Stitution of the spirem, but unfortunately, as stated above, the evidence on this point is somewhat ambiguous, and a definite decision in favor of either alternative seems impossible. Certain features of nuclei dividing by constriction, however, seem '0 throw some light on this matter. When amitosis by constriction 352 BOTANICAL GAZETTE [NOVEMBER occurs, the nucleus develops lobes and divides up into a number of daughter nuclei varying from two to a dozen or even more (jig. 41, 4, ¢). One cannot tell by observation whether a nucleus is about to divide into two or many daughters, for there is no apparent segregation of chromatin into parts corresponding in number with the number of small nuclei to be formed. Nor are the small nuclei necessarily equal in size or chromatin content. Sometimes the variations are very great; thus fig. 36 shows a cyst in which the primary nucleus has divided, leaving the nucleolus undivided in one of the daughters, while the other and smaller daughter nucleus has constricted or budded again to form a relatively minute nucleus at one side. It is difficult to believe that these three nuclei had their origin in equational divisions of the chromatin previous to the actual constriction of the mother nuclei. All appearances go to indicate rather that the factors © controlling the division of these nuclei are entirely disconnected from the behavior of the chromatin, and favor CHILp’s hypothesis (2) that amitosis is merely a physical process. But whether this be the case or not, nuclei so formed are normal and sometimes pass into mitosis. When this happens they show the four chromosomes characteristic of the species (fig. 35, a). More commonly, however, amitosis by con- striction is but an incident in the division of the chromatin, for the constricted nuclei are soon completely converted into groups of small nuclei by gemmation (see 6, fig. 3). Since the constitution of these nuclei is of great importance in this connection, I have introduced here a series of three drawings of nuclei from the same cyst. Fig. 38 shows a case of amitosis of the type most commonly observed, though it is not common in Synchytrium; in jig. 39 the two nuclei are completely separated but still touch each other; in fig. 4° one of the granules similar to those on the periphery of the other nuclei has formed a small nucleus by gemmation. The individuality hypothesis leads us to rather startling conclusions regarding the con- stitution of these nuclei. Each of the large nuclei must have four chromosomes. And since each of the granules on the periphery as the power of organizing a new small nucleus with four chromosomes; it also, if the chromosomes have a material continuity from generation to generation, must contain four chromosomes. In other words, the large nuclei must at one and the same time have four and 74 chromo” 1909] GRIGGS—MITOSIS IN SYNCHYTRIUM 353 somes. In these nuclei the small karyosomes number 4, 5, 6, 7. The respective nuclei must therefore have 16, 20, 24, 28 chromosomes, and still have no more than four! There seems to be no option but to conclude that in Synchytrium there is no morphological continuity of the individual chromosomes, nor is there any definite set of chromatin granules of whatever size which are passed on intact from nucleus-to nucleus. The number of chromosomes seems to be a physiological rather than a morphological constant. Not the chromosome but the nucleus itself seems to be the morphological unit of the lowest order. Apparently any mass of chromatin that is capable of organizing a nucleus at all, i.e., any particle of nuclear matter that is able to continue life and reproduce itself, whether it originally contained portions of all of the chromo- somes or of only one of them, will preserve the characteristic number of chromosomes along with the other hereditary characters of the species. “ Although such a hypothesis seems to be required to explain the phenomena of nuclear division in Synchytrium, it would not be wise to attempt to reach any decision as to its general applicability at. this time. In proposing it to account for these features of Synchytrium, the writer is not at all oblivious of the enormous amount of evidence which has been heaped up in recent years in support of the individu- ality of the chromosomes. The occurrence of protochromosomes in the nuclei of many cells (OVERTON 14); the persistence of super- numerary chromosomes in cases of polyspermy, etc.; and the remark- able size and shape differences among the individual chromosomes such as have been discovered in animals, notably by McCiunc and Montcomery, and recently in plants by SCHAFFNER (15) and Miss Hype (9), along with many other observations of a similar nature, are facts which give very great weight to the hypothesis of the indi- Viduality of the chromosomes. Nevertheless, it must be remembered that almost all of the evidence in favor of the individuality hypothesis is of Suggestive rather than demonstrative value. This was clearly recognized by all observers until about five years ago, but since that ime the amount of such evidence has increased to such an extent that Cytologists have been much less cautious than before in using the hypothesis. The renaissance of MENDEL’s law so favored the general 354 BOTANICAL GAZETTE [NOVEMBER acceptance of the chromosome hypothesis by making it highly desir- able on theoretical grounds to find the material bearers of hereditary units which the law seemed to demand, that practically all opposition to it was swept away, and it has come to be the groundwork on which present-day cytology has been constructed. If then the basis on which the theory rests is in any degree unproven, it is well for cytolo- gists to keep that fact clearly before them, that they may be guarded against making any false steps in blind adherence to an insecure hypothesis or of failing to notice any evidence which might throw doubt on the validity of their theory. The writer for his own part, however, has no intention of discard- ing the whole hypothesis of chromosome individuality on the basis of these observations on Synchytrium, or on the similar results obtained by CuiLp (2) from studies of representatives of nearly all the great animal phyla. The conflict of evidence for and against the hypothesis seems clearly to require us to keep the case open for the present. It is as tending to promote such a judicial attitude of sus- pended judgment among cytologists rather than as overthrowing the whole theory that the writer would have his results received. Summary The mitoses are all of the same type and occur simultaneously throughout the cyst. The spirems of amitosis are frequently indistinguishable from those of mitosis. The spindle is of the oomycete type, without centrosomes. The asters first appear as emanations from the condensed chro- matic mass of telophase, but quickly separate from the chromatin and their rays form the nuclear membrane. » The number of chromosomes is constantly four. ; In some sorts of amitosis an equational division of the chromatin previous to the division of the nucleus is possible, though there is no evidence of such a process. In other varieties of amitosis an equational division of the chro: matin does not seem to be possible, but rather direct division gives some indication of being merely a physical process as suggested by CHILD. Igo9| GRIGGS—MITOSIS IN SYNCHYTRIUM 355 Nevertheless, nuclei known to be derived by amitosis show four chromosomes. It is therefore concluded that in Synchytrium there is no morpho- logical or material continuity of the chromosomes from generation to generation of nuclei; but that the chromosome number is a physio- logical constant, like the other hereditary characters of the species. CoLtumMBus, OHIO Addendum After the foregoing paper had been completed and submitted for publication, Kusano’s “Contribution to the cytology of Synchytrium and its hosts’? (Bull. Col. Agr. Imp. Univ. Toyko 8: 80-147. pls. 8-II. 1909) reached me. KUSANO’S paper, for the most part, is based on observations of S. puerariae, which seems to be remarkably similar to S. decipiens, which he also used for comparison. He gives much space to the metamorphosis of the nucleolus (karyosome), which is unusually favorable for study in Synchytrium, showing that all the elements derived from the mother nucleus are concentrated in the karyosome of the daughter nucleus from which they are later withdrawn. He-figures the prophases and metaphases of the primary mitosis, confirming for the most part STEVENS’ observations, but like him failing to find the anaphases and telophases, which for some reason seem to be very difficult to observe. He then devotes con- siderable space to the secondary mitoses, obtaining results similar 'o those of the present paper; but his account of the prophases differs Considerably from that of the present writer. His series of figures, however, is not complete at this stage, and he admits (p. 102) that he had not been able to follow the formation of either the chromosomes or the spindle. Again, in the telophase there is a wide gap between his figs. 55 and 56, during which the aster is developed, a process about which he was left to conjecture (p. 127), incorrectly supposing that it originates from the cytoplasm. In addition to the method of segmentation by cleavage furrows described by HARPER, he reports 4 second method in which the sporangium walls are precipitated by the cytoplasm as in the endosperm of the higher plants. This form of segmentation occurs also in S. decipiens and, according to my observation, is more common than that described by HARPER. 356 BOTANICAL GAZETTE [NOVEMBER KusANno saw and figured the clusters of small nuclei due to various sorts of amitosis as described in my former paper (5), but he did not study them carefully and failed to ascribe to them the importance that they really possess. He repeats the statement of his preliminary paper that the chromosomes number constantly five, and thus adds strongly to the case against the individuality of the chromosomes made in the present paper. LITERATURE CITED 1. CHAMBERLAIN, C. J., The ovule and female gametophyte of Dioon. Bor. GAZETTE 42: 321-358. 1906. . CHILD, C. M. — as a factor in normal and regulatory growth. Anat. Anzeig. 30:271-297. 1907. . Davis, B. M., Oogenesis in Saprolegnia. Bor. GAZETTE 35:233-249; 320-349. 1903. . Griccs, R. F., On the cytology of Synchytrium. III. The réle of the centro- somes in the foroattens of the nuclear membrane. Ohio Nat. 8:277-286. 8 N w > 5: , Some aspects of amitosis in Synchytrium. Bort. GAZETTE 47?127- 138. 1909. 6. , A note on amitosis by constriction in Synchytrium. Ohio Nat. 9:513-515- 1900. . GUTTENBERG, H. R. von, —— Studien an Synchytrium Gallen. Jahrb. Wiss. Bot. 46: 453-477. 1909. - Harper, R. A., Sexual Beardie and organization of the sitio in certain mildews. Carnegie Inst. Pub. No. 37. 1905. 9. Hype, Eprru, The reduction division in the anthers of Hyacinthus orientalis. Ohio Nat. 9:539-544. 1909. - Kusano, S., On the nucleus of Synchytrium puerariae Miyabe. Bot. Mag. Tokyo 21: 218. 1907. , On the cytology of Synchytrium. Centralbl. Bakt. 197:538. 19°7- , On a disease caused by Synchytrium puerariae. Bot. Mag. Tokyo 22:1. ae 13. , On the “karyodermatoplast,” a nuclear-membrane-forming body. Bot. Mag. Tokyo 22:205, 206. 1908 (in Japanese without figures). 14. OvERTON, J. B., On the organization of the nuclei in the pollen mother cells of certain slants with especial reference to the permanence of the chromo- somes. Annals of Botany 23: 19-62. - SCHAFFNER, JOHN H., The reduction division in the microsporocytes of Agave virginica. Bor. Gareres 47:198-214. 1909. . STEVENS, F. L., The compound oosphere of Albugo bliti. Bot. GAZETTE 29:149~176, 225-245. 1899. ~J oo al ° - UL aa f=.) 1909] GRIGGS—MITOSIS IN SYNCHYTRIUM 357 17. STEVENS, F. L., Some remarkable nuclear structures in Synchytrium. Ann, Myc. gtallocgile ie 18. STEVENS, F. L. anp A. C., Mitosis in the primary nucleus of Synchytrium decipiens. Bor. GAZETTE 28: 2405-415. 1903. 19. WAGER, HAROLD, The nucleolus and nuclear division in the root apex of Phaseolus. Annals of Botany 18:39-53. 1904 20. WILson, E. B., Studies on chromosomes. V. The chromosomes of Meta- podius. A contribution to the hypothesis of the genetic continuity of the chromosomes. Jour. Exp. Zool. 6:147-205. 1909. 21. YAMANOUCHI, SHIGEO, Mitosis in Fucus. Bor. GAZETTE 47:173-197. Igog. EXPLANATION OF PLATES XVI-XVIII All the figures were made with a 1.5™™ immersion objective and ocular 12 giving a magnification of 2130, excepting fig. 36, which was drawn under a 4™™ dry lens with a magnification of 400. hey were reduced 4 in reproduction, can- celing the enlargement due to the camera and rendering them the same size as they were seen in the microscope. PLATE XV1 Fic, 1.—A vegetative nucleus. Fics. 2-4.—Three stages in the formation of the spirem from the same cyst, showing also the asters of the preceding division in process of disintegration. Fic. 5.—A large nucleus in spirem beside which is a small nucleus, derived by gemmation, still in the vegetative condition; from the same cyst as jigs. 6-9 and 13. Fics. 6-9.—The development of the spindle, from the same cyst. Fics. 10-12.—The contraction of the spirem around the equator of the spindle; nuclear een with its chromatic granules dissolving; from the same cyst. Fic, 13.—A young spindle with the chromatin so densely aggregated around the es that different parts cannot be made out; from the same cyst as jigs. 5-9. Fic. 14.—A spindle at metaphase, showing three of the four chromosomes. Fic. 15.—Chromosomes enlarging as they divide, each of them attached to the pole by heavy fibers. IG. 16.—A polar view of metaphase, showing the four chromosomes and the nucleolus. 1G. 17.—Chromosomes divided and beginning to separate Fic. 18.—Anaphase, showing separating chromosomes andthe heavy fibers Which connect them across the equator of the spindle; from the same cyst as figs. I ee IG. 19.—Anaphase; chromosomes lost in the deeply staining mass at the Poles; pinot fibers prominent. PLATE XVII Fic 20.—Anaphase similar to fig. 19, but remarkable for the very late persist- ence of the aster from the previous division. 358 BOTANICAL GAZETTE [NOVEMBER Fic. 21.—Similar anaphase, with the aster appearing unusually early. Fic. 22.—Connecting fibers withdrawn ; Fic. 23.—Spindle breaking apart in the middle. Fic. 24.—Radiations from the chromatic mass just beginning to appear at the lower pole; at the upper pole the focus has shifted out beyond the chromatin. Fic. 25.—A stage in the development of the aster intermediate between the two poles of the spindle shown in jig. 24 Fic. 26.—Aster strongly developed, weiile the chromatin remains extremely closely condensed; from the same cyst as jig. 24. Fic. 27.—Chromatin beginning to enlarge to form karyosome. Fic. 28.—Karyosome rounded off; nuclear vacuole just appearin 1G. 29.—Rays of aster beginning to bend around the vacuole to heat nuclear membrane; nucleolus and remnant of spindle lying below daughter nucleus. 1G. 30.—Rays of aster nearly surrounding the nuclear cavity; karyosome passing into spirem of the next mitosis; cf. fig. 2 Fic. 31.—A vegetative nucleus with the old ster lying along side. PLATE XVIII Fic. 32 Seine of a primary nucleus with halo and disintegrating nucleolus. 1G. 33.—T wo sporangia from a newly segmented summer sorus, showing the character of the mitoses and the independence of the segments. 1G. 34.—A spindle of one of the last mitoses of the sporangia. Fic. 35.—a, group of spindles formed by the division of a cluster of nuclei formed by amitosis, which lies in the center of a large cyst, the periphery of which contains the spindles of many small nuclei (b) derived by gemmation. Fic. 36.—Amitosis by constriction in a primary cyst, showing very great differences in chromatin content of daughter nuclei. Fic. 37.—An amitotic spirem in preparation for nuclear gemmation Fics. 38-40.—Amitosis by constriction and by nuclear gecuanation in the same Sis G. 41.—a, two amitotic nuclei; 6, an adjacent nucleus in spirem, which ee undoubtedly amitotic resembles mitotic spirems of figs. 4, 6; ¢ @ cluster of amitotic nuclei from the same section. : 1G. 42.—A spindle with five chromatin bodies, presumably chromatin granules of the spirem not yet fused into chromosomes; cf. fig. II. La] se > Ry w = N aX GRIGGS on SYNCHYTRIUM BOTANICAI. GAZETTE, XLVIII PLATE XVII BOTANICAL GAZETTE, XLVIII a =) _ a ae ~ = g Ww S ° ww 9 Oo ~~ aa ~) PLATE XVIII S BOTANICAL GAZETTE, XLVIII a 2) = ~ fb a en) O a Ss oP) [=I ° A) ae e) —_ pA ) INFLUENCE OF ELECTRICITY ON MICRO- ORGANISMS GEORGE E. STONE (WITH TWO FIGURES) The influence of electricity on the higher plants has been studied for many years, and there is considerable literature pertaining to this subject. The writer has carried on investigations in this line for many years, and some of the results have been published from time to time. Little or no attention, so far as we know, has been given to the study of the influence of electricity on the growth and multiplication of microorganisms, and it is our purpose to present in this paper the results of some of our investigations of the past two or three years. Microorganisms are favorable types with which to experiment, since they respond very quickly to stimuli, and, as might be expected, the results are more pronounced than is the case with the higher plants, where growth is relatively slower. The investigations given in this Paper were made on microorganisms common to water, milk, and soils, and some experiments were made with yeast. In some instances the natural flora common to water, milk, soils, etc., was used, and in others we experimented with pure cultures. Influence of electricity on bacteria in water Our first experiments with the influence of electricity on micro- Organisms were undertaken in connection with those common to water, and were designed with the object of rendering stagnant water more wholesome by a system of electrical treatment. Our studies had not extended very far, however, before we found that, instead of being decreased by means of this treatment, the bacteria increased €normously, especially when weak currents were employed. In this series we made use of the natural bacterial flora of water, while in others isolated species were experimented with. The experiments Were made in glass jars, in some cases those of rectangular form being used, and in others a wide-mouthed bottle. For the purpose of Measuring currents we made use of a Weston milliammeter and the 359) [Botanical Gazette, vol. 48 360 BOTANICAL GAZETTE [NOVEMBER usual bacterial methods were employed throughout these tests. All platings were made in Petri dishes in standard agar-agar, and the usual dilution methods were followed. The agar cultures were incubated at the usual temperatures, but the experiments were conducted at room temperatures in most cases, which ranged from 60° to 70° F." TABLE I Showing the influence of electrical stimulation (galvanic currents) on the bacteria in water. First cultures made 24 hours after treatment. NUMBER OF BACTERIA IN 1°° DATE OF MAKING ULTURE Normal | Trested June TO Vis fas GA0Z 43,642 BO es 3435 108,785 The experiment shown in the preceding table was made with two rectangular jars with approximately the following interior dimensions: height 16°™, width 12°™, diameter 4°™. These jars were filled with water obtained from a pond contaminated to a greater or less extent with sewerage. One was a normal or untreated jar, and the other contained electrodes composed of copper and zinc respectively, which were connected with wires and generated a current. The electrodes were of the same diameter as the jar, and one was placed in each end. A jar of this type constitutes 4 galvanic element (water cell), although the strength of current produced in this Fic. 1.—Jar, ieondal with case is very weak, averaging about 0.1 cotton ohag and copper and zinc milliamperes. Samples of the water were electrodes, used i in electrical ex- plated i in agar-agar 24 hours after treat- periments with milk and water. ment. On the second day, however, the experiment was discontinued. The results given in table I show In carrying on these experiments the writer is under special obligation to Mr. N. F. Monanan, a former assistant in our laboratory, who supervised most of details of the work. Ig09] STON E—ELECTRICITY AND MICROORGANISMS 361 considerable increase in the number of bacteria in water resulting from electrical stimulation. The number of organisms in the electrically treated jar increased from about 3000 to 43,000 on the first day, and to 108,000 on the second day. TABLE II Showing the influence of electrical stimulation (galvanic currents) on Pseudomonas radicicola. First cultures made 24 hours after treatment. NUMBER OF BACTERIA IN 1° DaTE OF MAKING CULTURE Normal Electrical January 23.... 6,000 15,000 anuary 24 50,893 3,178,246 January 27 52,741 4,287,002 January 31 50,217 5,210,112 February 4 50,217 February 8 42,112 10,200 February 12... 41,110 50,000 February 16... 35,000 4,000 TABLE Ii Showing the influence of electrical stimulation (galvanic currents) on Bacillus megaterium DeBary. First cultures made 24 hours after treatment. NUMBER OF BACTERIA IN 1° DATE OF MAKING : CULTURE . Normal Electrical February 25 ... II,000 243,000 February 28 .. 21,000 3,462,000 March 4.42. 25,400 600, Maren 67 p5. 20,000 4,566,400 March 12.2. 32,000 »950, March 165.451. 10,000 243,000 atch aa ass, 35,000 500,000 March 24...... 2, 22,000 The experiments given in the preceding tables were made in wide- mouthed jars approximately 10°™ in diameter and 21°™ high (fig. 1). Those containing the electrically treated water were provided with electrodes made of copper and zinc, which were connected with a wire as in the last experiment. The electrodes were about 4°" wide and long enough to extend over the lip of the bottle. The strength of Current developed in this galvanic cell was about 0.3 milliamperes, and it remained very constant throughout the experiments. The 362 BOTANICAL GAZETTE [NOVEMBER jars in every case were provided with cotton plugs and the whole outfit was sterilized before using. In these experiments pure cultures were used, and the medium, in this case water, was also sterilized before being inoculated. In one series (table II) the jar was inocu- lated with Pseudomonas radicicola (Beyerinck) Moore, from alfalfa; while in the experiments shown in table III the jar was inoculated with Bacillus megaterium DeBary, 1°° of a liquid culture medium being used to inoculate the jarsineachcase. Special care was taken to inoculate the normal and treated jars with the same number of organ- isms. An examination of the tables II and III will show that there was a marked increase in the number of bacteria during the first few days asa result of electrical stimulation. The maximum in one case was 52,000 for the normal and 5,000,000 for the treated; in another case 32,000 for the normal and 7,000,000 for the treated. It will be noted that the subsequent decrease in the number of the organisms was very marked in the electrically stimulated cultures, a feature due to the accumulation of zinc oxid in the jar, which is always present as a white precipitate in galvanic cells of this type- The presence of zinc oxid in water formed by the action of even com- paratively weak currents is toxic to bacteria, and the same toxic effect is well illustrated in galvanotropic experiments with roots. Some of our experiments which were made in much smaller jars failed entirely, as the smaller volume of water employed became concentrated so quickly with this substance that a toxic effect on the organism occurred very shortly after inoculation. Some of the precipitate obtained was dried and dissolved in flasks containing sterilized water. The jars were then inoculated with Bacillus megaterium DeBary, with the result that very little increase in the number of bacteria occurred where a 2 per cent. solution of this prepared precipitate of zinc oxid was used, and a 10 per cent. solution apparently killed all bacteria. In both of the experiments enumerated there occurred a slight falling-off in the number of organisms in the normal or untreated cultures. This is of common occurrence, however, in standing water, or even in soils under certain conditions. The strength of current developed in these experiments (0-1 and o.3 milliampere) was very constant, and from the results obtained it is evident that it acted as a marked stimulus. A large series of 1909] STONE—ELECTRICITY AND MICROORGANISMS 363 experiments made by us on the higher plants has shown that this current strength is very close to the optimum, and in all probability the optimum current strength for bacteria would differ little if any from that of the higher plants. We have employed this method of electrically stimulating bacteria and have enormously increased the number of organisms in cultures containing the legume Pseudomonas, which is used in inoculating soils. Some experiments were also carried on at the same time relative to the influence which electrical stimulation might have upon nitrogen fixation, but the results are incomplete and will not be given in this paper. The influence of electricity on bacteria in milk The purpose of our experiments in this series was similar to that in the experiments made with water; that is, to determine the effect of electrical stimulation on the microorganisms in milk. Our object, however, was not only to ascertain the effects of optimum currents, or at least those approximating the optimum on the bacteria of milk, but to observe the effects of strong electrical charges. Milk constitutes an excellent medium for the multiplication of bacteria and is well suited in some respects to experiments of this Mature. The experiments given in tables IV and V were conducted Similarly to the ones shown in the preceding series; that is, the bacteria Were stimulated by galvanic currents and the same size culture jars were used (jig. 1). About 1.5 pints of unsterilized milk were placed in each jar and a milliammeter indicated the strength of current to be approximately o.3 milliampere in the electrically treated samples. The jars were provided with cotton plugs and were sterilized before being filled with milk. The usual dilution methods were followed and the standard agar-agar was used for plate cultures. In practically all instances the counts are averages of three and four plates. Plat- ings were made of the milk at the beginning of the experiment, that is, before being electrically stimulated; therefore these counts, which are averages, answer for both the treated and untreated cultures. The results of electrical stimulation on bacteria in milk are shown In the experiments given in tables IV and V, but since milk sours and curdles badly in a few days it was necessary to limit the duration 364 BOTANICAL GAZETTE [NOVEMBER of the experiments. In the normal or untreated samples the increase in the number of organisms in one experiment was from 143,000 to 6,000,000; while in the treated samples the number reached 94,000,- ooo. In the experiment shown in table V the normal increased from 118,000 to 4,000,000; while the electrically treated reached 83,000,- ooo. The results are more striking than those obtained by the treat- ment of water, as might be expected, since there was more food avail- able for the use of the organisms in the latter series. TABLE IV Showing the influence of electricity (galvanic currents) on the bacteria in milk NUMBER OF BACTERIA IN rCC DATE OF MAKING CULTURE Normal Electrical May 10,2 BoM ws s.o. 143,395 143,395 May 17,-9 ALM; 345 Ss. 809,112 3,874,421 May 19,5 P.M es 54 1,470,441 86,592,600 May 18,9 A. M....... 6,082,542* 94,851,806* * Milk sour. TABLE V Showing the influence of electricity (galvanic currents) on the bacteria of milk NUMBER OF BACTERIA IN 1CC DATE OF MAKING 2 CULTURE Normal Electrical May 17, 10 A.M...... 118,542 118,542 May 31955 PioMs ok. 678,333 1,848,806 May 18, Io A.M...... 1,026,533 41,778,766 May 18, 5 P.M....... 4,591,500* 83,363,866* * Milk sour. Another series of experiments was undertaken to demonstrate the effects of static electricity on bacteria in milk. For this purpose We employed a static machine of the Tépler-Holtz type, which was designed for X-ray work and is capable of producing a spark six inches or more in length. The method of plating, etc., was the same as has been previously described, and the culture jars were of the same type, except that the electrically stimulated jars were covered with tinfoil in the same way as a Leyden jar. The copper and zinc plates were dispensed with, of course, and the milk was charged direct from the static machine. In this series three jars were used: 4 . j 1909] STONE—ELECTRICITY AND MICROORGANISMS 365 one normal, one treated with positive, and one with negative charges. — The milk in the electrically treated jars was charged with sparks from a static machine in the same way that a Leyden jar is charged, an electroscope being used to determine the nature of the charge. In the milk experiments which follow it should be pointed out that the charges varied considerably. TABLE VI Showing the influence of static electricity (positive and negative charges) upon the bacteria in milk. Electrical jars charged with one spark each June rr. NUMBER OF BACTERIA IN 1CC Date OF MAKING ETI Electrical (positi Electrical (negative Normal pais a oe Gata 1S are ane eee ee 8,342 9342 8,342 Wee 865s ee 69,000 196,300 ieee Gee PUNE 920 ae 568,000 000 67,500 | 3S ee eee 1,213,000 16,432,500 19,374,600 / Bete tes ee 9,876,400 0,500,000 000,000 ne Sa ae ee 27,432,000 153,461,000 be ane te Se ee oe 190,500,000* 267,000,000* 233;339;000 * Milk curdled. TABLE VII Showing the influence of static electricity (positive and negative charges) upon the bacteria in milk. Electrical j jars charged with 1o sparks each June 2. | NUMBER OF BACTERIA IN ICC Date OF MAKING : CULTURE Electrical (positive Electrical (negative Normal - charge) charge) nade BIO Aas ae 65,000 ove 565,000 une 2, 5 “ fie ape 73,0 597; 245333 June 3, 10 A. M 19,057,000 23,443,066 18,088,333 gene's, oP M5, 5. 107,440,000 151,510,000 I ee June 4,10 A.M., 2 201,413,333* 287,380,000* 212,816,666 * Milk sour. In the experiment shown in table VI one large spark was given each electrically treated jar, one being given a positive and the other 4 negative charge, and in the one shown in table VII the number of sparks was increased to 10. The electrical treatment, the results of which are shown in table VI, where the milk was charged with a Single spark and cultures made every 24 hours, gave rise to a decided acceleration. This acceleration was perceptible at the time of the 366 BOTANICAL GAZETTE [NOVEMBER first plating and continued throughout the experiments, which lasted six days. The results shown in table VII indicate that the treatment given caused less acceleration. In this case platings were made at shorter intervals. The first plating was made seven hours after stimulating; at this time scarcely any acceleration was shown, which indicated the possibility of the death of the organisms by treatment, while dur- ing the same period the normal nearly doubled in the number of bacteria. The later platings, however, made at 24, 31, and 48 hours respectively after stimulation, showed a greater increase than that — given by the normal, but the ten charges given in the latter experiment were evidently too strong to obtain the optimum results. In both the experiments enumerated (tables VI and VII) the milk was kept on ice. TABLE VIII Showing the influence of static electricity (positive and negative charges) upon the bacteria in milk. Electrical jars charged with 100 sparks each. NUMBER OF BACTERIA IN ICC DaTE OF MAKING CULTURE : i Electrical (positi Electrical (negative Normal sy ctor iy é charge) May 31, 10 A. M...... 528,000 528,000 528,000 May st,

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A table ing oes roximate cost of additional Separates mted on an order blank which accompanies the ctw ee copy will be sent on request. — a ed August 21 1896, at the Post-Office at Chicago, as second-class matter, under Act of Congress March 3, 1879. Ee Ba eb ba VOLUME XLVIII NUMBER 6 BOTANICAL (GAZETTE DECEMBER 1909 DIOON SPINULOSUM ! CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY I 31 CHARLES J. CHAMBERLAIN (WITH. SEVEN FIGURES) hice well-defined species of Dioon have been found in the Mexi- can tropics: D. edule Lindl., D. spinulosum Dyer, and D. Purpusti ose. LD, edule, which was described as early as 1843, is now quite well known. Although D. Purpusii was described only a few months ago, the species had often been seen, but had been mistaken for D. edule, which it resembles in its general appearance. I was told by a Mexican botanist that I should find D. edule along the Mexican Southern R.R. in the neighborhood of Santa Catarina, State of Oaxaca. He said there was no other cycad in that region. The — 3 plant was easily found, and I at once saw that it was a new species intermediate between D. spinulosum and D. edule. The plant called D. edule in fig. tor of WIELAND’s American fossil cycads is the new D. Purpusii, as plainly indicated by the staminate cone and _ by the leaves. MacDovucat and Rose collected cones of the new _ Species in 1906 in the Tomellin cafion, where it was well shaded by bushes and small trees. Purpus in 1908 collected seeds and bracts in _ the Sierra Mixteca, Puebla. In April of the same year I saw the species at various places between Santa Catarina and Tomellin, growing in dry, exposed situations, associated with cactiand Beaucarnea. Rosk? describes the staminate sporophylls as “bracts with recurved ovate _ tips,” apparently supposing that the sporangia were borne on the sdipee a prosecuted with the aid of a grant from the Botanical Society of America 2 RosE, J. N., Studies of Mexican and Central American plants. Contrib, U. S. Nat. Herb. 12: 259-302. 1909. 401 402 BOTANICAL GAZETTE [DECEMBER adaxial surface, but of course they are on the under surface and the tips point up instead of down. His description of “seeds about 4°™ in diameter” needs confirmation; 4°™ in length would be more probable. In general habit, in the straight, stiff, ascending leaves, D. Pur- pusii resembles D. edule, and the leaflets have the texture of those of D. edule, but they retain in some degree the spinulose character of those of D. spinulosum. In the number of sporangia on a microsporo- phyll, D. Purpusii is intermediate between D. spinulosum and D. edule. The ovulate sporophyll is rather slender and tapers gradually to a point, in this feature resembling D. edule and differing decidedly from D. spinulosum. Dioon spinulosum Dyer was described by E1cHLER’ in 1883, the description being based upon a few leaves and a few trunks with- out leaves. Since the largest leaf was only 65°™ in length, the plants must have been very small. One of the trunks received by EICHLER produced a leaf which his figure shows to be that of a plant only a few years old. The material came from a nursery in Cordoba, State of Vera Cruz, Mexico, and, according to the gardener, the plants grew wild in the neighborhood of Tuxtla. The striking feature is the spinulose leaf. No cones were found, and so EIcHLER remarks that it might seem doubtful whether the plant is really a Dioon (“Es méchte daher zweifelhaft erscheinen, ob die Pflanze wirklich ein Dioon ist’’). Dyer obtained a leaf from Yucatan, and since the locality was given as Progreso, the leaf probably came from a cultivated specimen. EICHLER agreed that Dyer should describe the new species. The description, based upon the single leaf, is as follows:4 Folia breviter petiolata, elongato-lanceolata, rigida, plana, pinnatisecta, ad 3 pedes longa; segmentis circiter 70 utroque latere, mediis majoribus subop- positis lineari-lanceolatis breviter acuminatis 18-23-nerviis, ad 4 pollices longis media latitudine semipollicaribus, basi angustiore, utroque latere spinulis pun- gentibus basim versus integerrimis, inferioribus in dentes palmatifidos desinenti- bus. Sétrobili..... South Mexico, Tuxtla; Yucatan, Progreso. ae Hoge). Herb. Kew. 3 EICHLER, A. W., Ein neues Dioon. Gartenflora 2:411-413- 883. 4 Dyer, W. T. iste Cycadaceae, in Biologia ee -Americana Botany 3:190-195. 1882-18 1909] CHAMBERLAIN—DIOON SPINULOSUM 403 : During my second trip to Mexico, in 1906, I saw small specimens of Dioon spinulosum in the park at Vera Cruz, but did not find it growing wild. Gov. TEoporE A. DEeHEsA, of the State of Vera Cruz, who has repeatedly assisted me in my investigation of Mexican cycads, again used his influence in my behalf, and I am also under renewed obligations to Mr. ALEXANDER M. Gaw, of the State Bureau of Infor- mation, Jalapa, Mexico, for his continued interest and active coopera- tion both in securing material and often in furnishing field notes. Mr. Gaw found that the plants in the park at Vera Cruz came from Tlacotalpam, a town southeast of Vera Cruz, and he also found 4 that most people do not distinguish the two species, D. edule and _ D. spinulosum, for he was told that the plants in the park at Vera : Cruz could be found growing wild in the vicinity of Tlacotalpam, _ Catemaco, and elsewhere in the canton of Tuxtlas, and between Palmar and Colorado on the Interoceanic R. R. Doubtless the infor- mation in regard to the first three places was correct, but since I had found only D. edule in the Palmar-Colorado region, Mr. GAw sent a man through that entire district with a leaf of D. spinulosum as a guide. The man found D. edule in abundance, but failed to find a _ single specimen of D. spinulosum. In Vera Cruz the plant is called __ palma de Dolores, the same name which in the Jalapa region is applied to D. edule. The name tio tamal, which is commonly given to _ D2. edule because the seeds are used in making éamales, does not seem to be applied to D. spinulosum, although its seeds are edible. _ The natives of the coast region call both the plant and the seeds _ chicalitos, a name which I have not heard applied to D. edule. _ Froma park in Tlacotalpam Mr. Gaw secured a large ovulate cone of D. spinulosum, and he was told that the specimen came from the Sierra de Oaxaca Mountains near Tuxtepec, where the plant was Said to be very abundant. As the Tlacotalpam cone had only abortive seeds, Mr. Gaw, after repeated efforts, succeeded in securing from the Tuxtepec region an ovulate cone in which pollination and fertiliza- _ tion had taken place. Later he secured a cone with ripe seeds, which germinated readily. With the material Mr. Gaw sent the rather Startling information that, according to the natives, the cones are borne below the crown of leaves and not above the crown, as in D. ed 404 BOTANICAL GAZETTE [DECEMBER In March 1908 I visited southern Mexico to collect D. spinulosum. While on the way to Tuxtepec, I was informed that a plant which seemed to agree with my description, except that it was much taller, could be found near Tierra Blanca. In the mountains west and a little north of Tierra Blanca I found a few specimens and was told that plants were more numerous a few miles farther south. The information was correct, for on the immense hacienda of the Joliet Tropical Plantation Company, a short distance from Tierra Blanca and about 60 miles south of Vera Cruz, magnificent specimens are abundant. Mr. J.C. DENNIs, superintendent of the plantation, very generously furnished horses, guides, and the hospitality of his palatial home while I explored the mountains and secured photographs and material. The plant is usually well shaded, growing among the prevailing limestone rocks which have given name (Tierra Blanca) to the region. From Tuxtepec, a town on the Papaloapam River about forty miles southwest of Tierra Blanca, half a day’s ride on horseback brings one to the mountains where D. spinulosum is as abundant as at Tierra Blanca. In some places it is the only large plant, and it would not bean exaggeration to speak of a Dioon forest. Beautiful specimens, which might have been the pride of any conservatory, had been cut down to get the cones, because it was easier to cut the tree than to climb it. The natives use the young seeds in making éamales, as in D. edule, and at a later stage the dry stony seed coat is a common plaything for children. At Tuxtepec the dry seeds, each pierced with two holes, sell for fifteen cents a dozen. The Indians said that the plant extends some distance farther south, but that it does not occur on the western (Oaxaca) side of the mountains. Dioon spinulosum, with the exception of the Australian Cycas media, is the tallest cycad known, and its slender trunk with a large crown of leaves gives it the appearance of a palm (fig. 1). I measured specimens 12™ in height, and Drs. BARNES and LAND, visiting the Tierra Blanca region a few months after my return, found speci- mens more than 16™ in height, almost as high as the tallest known specimens of Cycas media. The slender trunk and graceful curve of leaves are in striking contrast with the stocky trunk and straight, rigid, ascending leaves of D. edule. 1909] CHAMBERLAIN—DIOON SPINULOSUM 405 1.—Dioon spinulosum on the et ae de Joliet near Tierra Blanca, March Fic. 1908;_ the tallest plant is about 10™ in heig - 406 BOTANICAL GAZETTE [DECEMBER The ribbed surface of the trunk is due to successive crowns, and affords some basis for an estimate of the age of the plant, but in the lower part of the trunk of tall specimens the ribs may become too obscure for accurate counting. The scars of the individual leaves, which are so distinct in D. edule, are so obscure in D. spinulosum that counting in the lower portion of large trunks is out of the question. Whether the duration of the crown is two years, as in D. edule, I was not able to determine, but assuming the duration to be two years, the tallest specimens might not be more than 4oo years old. How- ever, any estimate can be little more than a guess, until the duration of crowns, and the effect of scale leaves, cones, and resting periods upon the growth of the trunk have been studied much more carefully. Still, I am inclined to believe that a 10™ specimen is no older than a 1™ specimen of D. edule. At the base the trunk is much enlarged, often having twice as great a diameter as it has o.5™ higher up. The roots are often exposed for considerable distances, especially in precipitous places, where a root may hang down along the surface of the rock. One root hanging down in this way was exposed for a distance of more than 12™ and was 5°™ in diameter where it again entered the soil. Cutting through the trunk, which is not nearly so hard as that of D. edule, it is seen that there is a single zone of wood surrounding the large pith. The origin and development of the vascular cylinder, as seen in embryos and young seedlings, is being studied by HELEN A. Dorety. Both EICHLER and Dyer gave accurate descriptions of the leaves as they appear on small plants. E1cHter’s largest leaf (65° in length) had 38 pinnae, the lowest of which were rudimentary. DvyER’S leaf was about 1™ long, with 70 pinnae on each side. On plants 2™ or more in height the leaves reach their full size, so that leaves 2" long, with 100 leaflets on each side, are not uncommon, while one leaf measured 2.2™ in length and had 117 leaflets on each side, the leaflets being 20°™ long and 1o™™ wide. There is great variation in the leaflets, some only 14-15°™ long being 15™™ wide. ‘There are 5-8 sharp spines on each margin of the leaflets of large leaves. The lower leaflets become more and more reduced, until the lowest ones are nothing but spines, so that the leaf bears considerable resemblance 1909] CHAMBERLAIN—DIOON SPINULOSUM 407 to that of Encephalartos. The leaves of seedlings have comparatively few leaflets, the first leaf sometimes having less than a dozen on each side. It is interesting to note that in seedlings the leaves have no reduced leaflets, even the lowest being as perfectly formed as those in the middle of the leaf. The leaflets of seedlings have fewer spines than those of older plants, there being only 2-6 on each margin. The midrib is not so large as in D. edule and the leaves are much thinner. A few leaflets of a leaf of medium size are shown in fig. 2. Remembering that the natives had reported cones growing below the crowns, one would naturally think of the condition in Bennettitales. Fic. 2.—Portion of leaf of Dioon spinulosum from a specimen at Tlacotalpam; X4; the cone shown in fig. 4 came from the same plant. A glance at jig. 3 will show that the cone does hang down below the crown. An examination of the apex of the stem shows, however, that the cone is borne in the center of the crown as in D. edule, but that a considerable elongation of the peduncle, together with the great weight of the cone, causes the cone to bend over, slip between the leaves, and thus hang below the crown. Consequently no seeds are found in the nest of the crown as is so commonly the case in D. edule, where the germination of seeds in this position often gives rise to the appearance of branching. In D. spinulosum branching is rare. Seedlings are found for a considerable distance around the large ovulate plants. The natives say that at maturity the cone bursts with a loud noise, scattering the seeds, or coyoles, the plant being called coyolillo. [DECEMBER BOTANICAL GAZETTE 40 ew “Os \e | ANS S/ % mG. 5 é asl pee AM POG Fae ' te 81Ep pee) hy, Pana fee) Fic. 3.—Dioon spinulosum with ovulate cone, on the Hacienda de Joliet, March 1908. 1909] CHAMBERLAIN—DIOON SPINULOSUM 409 The ovulate cone is the largest yet known for any gymnosperm. In March, cones weigh- ing 14 kilos were not infrequent, and_ occa- sionally a cone had reached a weight of 15 kilos. Since the seeds are not fully mature until October, it is safe to assume that the cones increase somewhat in weight after March, the time of my visit. The cone is cylindrical ovoid (jig. 4), its general habit distinguishing it at once from the ovoid cone of D. edule. It reaches a length of 50°™ and a diameter of 27°”, but the average cone is about 20 per cent. smaller than these meas- urements. The ovulate sporo- phylls are very hairy, as in D. edule and D. Purpusii, but are much more closely imbricated, there being no_ pro- jecting tips as is always ‘ Fic. 4.—Dioon spinulosum; ovulate cone from a the case in the URES ee. ates at Tlacotalpam; x 4; November 1906. of D. edule and probably in D. Purpusii. In regard to the latter species, however, my statement is based upon only a single sporophyll. The 410 BOTANICAL GAZETTE [DECEMBER sporophyll of D. spinulosum is thick, fleshy, and rounded or obtuse at the apex, contrasting again with the long tapering sporophylls of D. edule and D. Purpusii. The contour of the exposed portion of the sporophylls and the close imbrication is seen in fig. 4, especially near the apex of the cone. The seeds are white and perfectly smooth, but may become slightly yellowish when mature; their length varies from 4 to 5.5°™ and the diameter from 2.5 to 3.5°™. Some of the ovules have the’ Fic. 5—Dioon spinulosum; dorsal Fic. 6.—Dioon spinulosum; ovulate view of an ordinary sporophyll, the ovule sporophyll, from the cone shown in fig. 4, on the left showing the false stalk; from with five ovules, three of which can be seen a cone received from Tuxtepec, Apri on the left side, but only a portion of one of 1907. X#. the two on the right side is visible. X ?. false stalk, characteristic of the genus, but it is not as frequent as in D. edule (fig. 5). In one cone, with only abortive ovules, there were frequently more than two ovules on a sporophyll, in some cases aS many as five or six (fig. 6). Cycas, the most ancient genus of the family, regularly produces more than two ovules on a sporophyll, and in Dioon the production of more than two ovules is doubtless a recurrence of the ancient habit. In rare cases, I have noted as many as four ovules on the sporophylls of Zamia floridana and Ceratozamia mexicana. 1909] CHAMBERLAIN—DIOON SPINULOSUM 411 As yet I have obtained only one staminate cone, and that not from the field but from Professor TRELEASE, of the Missouri Botanical Garden. Where the speci- men came from could not be determined, except that it had been secured from the nursery of W. A. MANDA (S. Orange, N. J.), who had gotten it in a miscellaneous collection of unknown sources. This cone, which atrived in Chicago July 25, 1907, measured 21°" in length by 10°™ in diameter, and since the pollen was nearly mature, this must be about the size before the elongation of the axis begins to separate the sporophylls and liberate the pollen. The general appearance of the cone is shown in fig. 7. The shape of the micro- sporophyll and its general appearance is about as in D. edule, except that the microsporangia are much more numerous, the aver- age number on a micro- sporophyll being about 750; while in D. edule the average falls a little below 300. The number in D. Purpusii is between 300 and 4oo. In all three species the sporan- Fic. 7.—Dioon spinulosum; staminate cone rom a plant in the Missouri Botanical Garden, x July 1907. gia are in sori of 3, 4, 5, and 6 sporangia, with 4 and 5 the most frequent numbers. 412 BOTANICAL GAZETTE [DECEMBER While it is hardly safe to arrange the three species in an evolu- tionary sequence before the life histories have been studied, it seems to me that D. spinulosum is the oldest and D. edule the most recent, so that the series should be D. spinulosum, D. Purpusiui, and D. edule. In favor of this sequence it may be said that D. spinulosum has a spinulose leaf throughout its life history, while D. edule shows the spinulose character only in the seedling, the later leaves gradually becoming entire. D. Purpusii has a leaf which is slightly but con- stantly spinulose in the adult plant. Its seedling is not known. Regarding the spinulose character of the seedling leaf of D. edule as due to recapitulation, D. edule is a later development than D. spinulosum and has come either from D. spinuloswm or from some unknown form with spinulose leaves. The leaves of D. edule and D. Purpusii present about such characters as we should expect in D. spinulosum, if this species should be brought from its well shaded habitat into the dry hot places where the other two species are found. I believe that throughout the Cycadales there has been a gradual reduction in the number of sporangia on a sporophyll. On this basis the sequence would be as I have given it. On the other hand, it must be admitted that in D. edule the ovulate cone is not so compact and the megasporophylls have not lost so completely the character of the vegetative leaf, which must be assumed as the ancestral form of both kinds of sporophylls. Since the original description of D. spinulosum was necessarily inadequate and incomplete, it seems worth while to describe the species from the more abundant material now available. DI0oN sPINULOsUM Dyer.—Adult plants 2-16™ in height; stem slender, with conspicuous transverse ribs, and a single zone of wood; leaves 1.5-2™ long, curved, with 80-117 leaflets on each side; leaflets 15-20°™ long, ro-15™™ wide, with 5~8 spines on each margin, the lower ones gradually reduced to mere spines; first leaf of seedling with as few as a dozen leaflets on each side, the leaflets with only 2-6 spines on each margin, lower leaflets not at all reduced; ovulate strobilus cylindrical ovoid, 35-50°™ in length, 20-27°™ in diameter; sporophylls densely hairy, closely imbricate, the exposed portion rounded or obtuse at apex; — seeds smooth, white, 4-5.5°™ in length, 2.5-3.5°™ in diameter; staminate strobilus elongated ovoid, 21°™ in length, ro°™ in diameter; exposed portion of sporophyll hairy, obtuse; microsporangia about 750 on a sporophyll. 1909] CHAMBERLAIN—DIOON SPINULOSUM 413 Observed growing wild at Tierra Blanca (State of Vera Cruz) and at Tuxtepec (State of Oaxaca), Mexico. Material has been collected at intervals and a future account will deal with critical stages in the life history. THE UNIVERSITY OF CHICAGO THE INFLUENCE OF GRAVITY ON THE DIRECTION OF GROWTH OF AMANITA STELLA G. STREETER (WITH THIRTEEN FIGURES) The following account is a record of a series of experiments carried on at the Biological Laboratory of the Brooklyn Institute at Cold Spring Harbor, under the direction of Professor D. S. JOHNSON, during the summers of 1906 and 1908. The object was to determine, if possible, the reactions of some of the common toadstools to the gravity stimulus. The main points under consideration are the promptness and accuracy of the response, the duration of the response after an efficient stimulus, the location of the zone of elongation, and its relation to the responsive zone. The conclusions here stated were drawn from observations made on about 3000 specimens, collected in the woods and replanted where conditions could be con- trolled. With the greatest care not more than one out of every ten planted yielded a satisfactory record. The agarics break easily, often from their own weight, when placed in a horizontal position; some shriveled instead of developing, and many were infested with the larvae of various insects, which fact was not apparent until the toad- stool was near maturity. The species used in these experiments were Amanita phalloides Fr. and A. crenulata Peck. These forms were chosen because they have long stipes, because transplanting seemed in no way to retard the normal development, and because they were very abundant. The food supply is stored in the button, so that the plant is not seriously affected by removal from the mycelium. The plants were collected from the woods just after they broke through the ground, at the stage when the pileus is beginning to break through the volva. Each was taken up carefully with some of its surrounding soil, carried to the laboratory, and there planted again in a tumbler. When it had been allowed to rest in the normal vertical position in a dark chamber for a short time, a careful drawing of each specimen was made in the following manner. The plant was placed, with the Botanical Gazette, vol. 48] . [414 1909] STREETER—DIRECTION OF GROWTH OF AMANITA 415 stipe horizontal, at an accurately measured distance, before a sheet of paper firmly supported on a vertical drawing-board. In front of the toadstool and always at the same distance from it as the paper was fixed a black screen having a pinhole aperture. The drawing was made by looking through the opening and tracing the outline of the plant as it appeared against the paper. Other records were made in this way from time to time, depending upon the object of the experiment. The plant was in no way disturbed, and these records showed all changes of position in the vertical plane, and from them it mas possible to measure these changes in units of angular measure- ments. : fo Fic..2 Fic. 1 M Fic. 1.4. crenulata, 11° from perpendicular.—Fic. 2. A. crenulata, 8°5 from perpendicular. __ A few simple experiments showed that the forms used were positively heliotropic. Specimens planted in tumblers were placed in boxes which were painted black on the inside.” One entire side of each box was left open and the boxes were placed in a west window ‘with the exposed side toward the light. After standing in this position for 24 hours, the plants had bent 8° to 12° toward the light (figs. 1,2). In fig. 1 the main axis of the toadstool is shown inclined 11° from perpendicular, and in fig. 2, 8°5. To avoid light stimulus, all experiments with reference to geotropism were performed within a moist dark chamber, which in turn was kept in a dark room. _ After the pileus broke through the volva, it took the stipe about 24 hours to attain its full length in A. crenulata, and nearly 36 hours ‘in A. phalloides. With a few exceptions this time element was con- 416 BOTANICAL GAZETTE [DECEMBER stant. This short period of development necessitated that all observations on one plant should be made within 36 hours. In those experiments which required that the plant be held in a horizontal position, the tumbler containing the toadstool was sup- ported firmly on a wooden block by a band of tin nailed securely to each side of the block (figs. 3, 4). A slender insect pin was placed in Fic. 3.—A. phalloides, in which supra-curvature has been neutralized. the center of each toadstool as a continuation of the axis of the stipe (also shown in the figures). This pointer made it possible to measure the amount of curvature accurately. After being collected and planted, each specimen was left in the normal position long enough to counteract any stimulation received during its transference and then it was placed on its side in the dark chamber. Usually the pileus does not become fully extended until after the 1909] STREETER--DIRECTION OF GROWTH OF AMANITA 417 stipe has ceased to elongate (fig. 5). In 24 hours after the toadstool had reached its maximum height, the pileus expanded and its diameter increased 1.2°™. In all cases where the plant was placed on its side after the stipe had reached its full length, but before the pileus Fic. 4.—A. phalloides, from which the pileus, except that part directly above the Stipe, has been removed. had fully opened, the pileus continued to expand; there was, however, no upward bend in the stipe (also shown in fig. 5). After the stipe attains its full length there is no longer any response to gravity stimulus. When a young plant, in which the entire stipe is still elongating, is placed on its side in the dark, the tip of the stipe begins to bend 418 BOTANICAL GAZETTE - [DECEMBER upward after 40-60 minutes. This curvature is continued for about 24 or 36 hours, aie aoe: upon the species, until the tip = the eas - 65cm Fic. 5.—A. crenulata; a, height 6.5¢™, diameter of pileus 5.8°™; 6, 24 hours later, height 6.5°™, diameter of pileus 7¢m, Fic. 6.—A. crenulata: a, as planted; b, 24 hours later, showing supra-curvature of 31°. is carried up to and beyond the vertical position, and the original lower edge of the pileus is carried above the horizontal plane (jig. ©). 1909] STREETER—DIRECTION OF GROWTH OF AMANITA 419 In experimenting with the stem of Cephalaria procera, one of the teasels, Sacus (1888) found that this supra-curvature was neutralized BA ish Sirty AT ty eal EE | _ __ Fic. 7.—A. phalloides: a, as planted; 6, 6 hours later, poms tie eet : of 20°; c, 17 hours after planting, having returned to 10° below vertical; d, 30 hou _ after planting, tip of stipe vertical. and the stem soon moved back to the vertical position. In the case 420 BOTANICAL GAZETTE [DECEMBER When young specimens of A. phalloides, which have longer stipes and respond more quickly, were used, the tip of the stipe was carried beyond the vertical 2° to 20°, then it stopped and moved back toward and beyond the vertical 1° to 6° on the other side, and by a repetition of this process finally came to rest in the vertical position. ig. 7 shows a series of drawings of one specimen of A. phalloides in which the supra-curvature was neutralized. Fig. 3 shows this toadstool just before it came to its final vertical position. This fluctuation only takes place if the plant is still growing when the induced response ceases. In an attempt to locate exactly the perceptive zone, all the pileus except that part directly above and which forms a continuation of the stipe was removed in the manner shown in fig. 8. These plants were then allowed to develop in the dark in a horizontal position for 24 hours, and the result is shown in fig. 8. The stipe itself bent, but there was no curvature in that part which belonged to the pileus. This shows that the responsive zone is not situated within the pileus. The entire pileus was then carefully removed from the tip of the stipe in many plants by a transverse cut where the gills join the stipe. Each specimen was then placed in a horizontal position in the dark and allowed to remain 24 hours. The geotropic response here was normal (fig. 9). The stipe, which was bent downward at first, began to bend upward slowly, then more rapidly, carrying the tip beyond the vertical. This shows that the responsive zone is situated within the stipe. A further attempt to locate the responsive zone was made. Glass tubes were cut in pieces of different lengths and these were placed over the bases of the stipes of plants from which the pileus had been removed. This left 1-4™™ of the upper end of the stipe exposed beyond the end of the tube. These tubes were held firmly in a horizontal position by wire, and the plants were kept in the dark for 24 hours. In every case where elongation had not ceased, there was a decided upward curvature of the stipe beginning at the end of the glass tube (fig. 10). In this case the stipe was 8™™ long, 2"™ of this projecting beyond the end of the tube when the experiment was set up. After twenty-four hours the stipe projected 217” beyond the tube. It had curved upward at the end of the tube, making an 1909] STREETER—-DIRECTION OF GROWTH OF AMANITA 421 angle of 145° with the position from which it started. This shows that at least part of the responsive zone is very near the tip of the stipe. In other cases, where the stipe had nearly reached its greatest elongation, the result was the same (fig. rz). Here the stipe was Fic. 9 Fic. 8 Fic. 8. A. crenulata: a, entire; b, as planted, the pileus having been removed as indicated by the lines, dotted lines show depth of pileus; ¢, 24 hours later, showing that curvature takes place in stipe, not in pileus.—Fic. 9. A. crenulata: a, entire; b, as Planted, the pileus having been removed by transverse cut ab; ¢, 24 hours later, show- ing curvature of 124°. 56™™ in length, of which r™™ projected beyond the end of the tube. + . . . . mm In this case elongation continued until the stipe projected 3™™, and it then showed an upward curvature of 2 3°. In this case the respon- sive zone must have been within 1™™ of the tip at the start. In order to determine the distribution of the zone of elongation, 422 : BOTANICAL GAZETTE [DECEMBER the stipes of a great many specimens in all stages of development were measured. An accurate record of the length of the stipe at the beginning and end of growth was kept. The stipe was marked off into 2™™ lengths with dots of waterproof India ink. It was possible, Fic. 10 Fi, 11 Fic. 10. A. crenulata, 24 hours after planting; base of stipe held in glass tube; tip curved 145°.—Fic. 11. A. sane, 24 hours after planting; base of stipe held in glass tube; tip curved 23°. when growth ceased, to tell in what region elongation had taken place and where it was most rapid. A few of these records are given below. n .] eo i O a 4/8 /ele |g Bg ‘ g Bees Ca ic rh, 2 a = oo - S . aw | 3 3/38 3/6 | or a 3 Fs 2, tS | Ss » & 15 S28 o ay n gaa en & /A | 8 be ee 3 E Se | 2% “3 a] 2 g =] sR cs i>! & “Bo & a 7 o 3 ald E = a 9d ve i 4 silo 18 aoe “ o es ei eg , |Ss1° | 218 jee Seq 2 2 = gz | 33 5 2 |S 64 Be > > = =I be] 5 |S Bla Sis |ss 20.5 =) a so ao eM et) 2h vo bo Sp ~ am a am ag cr) | esiagi g BO) gw gao a rol + es ES & 5 |/o-|o% &§ aos eee of] 6 = Zin |i a 12 25) 4 4 A Oo 3) mm./mm./mm.|mm.|mm 3 m mm. mm. % % | hours 110 7 | 33 | 26 © | 7-10-53-34-0 2 100 36 216 | 20 | 50 | 30 | 20] 0 | 3-3-3-3-5 4-3-2-2-2 4 100 36 218 | 30 | 68 | 38 | 30 | 0 | 2-2-3-3-4 4-4-3-3-2 ese 1-1 44.1 | 100 36 157 | 40 | 72 | 32 | 40 | © | 3-4-3-3-2 2-2-I-I-1| I-1~1-1-1| I~1-1-1-1] 55.5 | 100 36 104 | 20 | 34 | 14 | 20 | © | 1-2-2-2-2 I-I-I-I-1 58.8 | 100 36 142 | 30 | 42 | 12 | 20 | ro | 2-2-2-1}-14 | 1 971.4 | 66.6] 36 148 | 42 | 52 | 10 | 20 | 2 I-2-I-I-1 i-1-1-44 80.7 | 47.6} 36 138 |102-|104 | 2| 81 9 4 98 7.8] 36 123 | 36 | 364 4] 2 | 34 | 4-c-c-o-0 : 08.6 5.5] 36 The specimens described above were grown in a horizontal posi- tion, and the measurements were taken on the lower side. Comparing the length of the stipe at the beginning and at the end of the experi- ment, and then comparing the length of the zone of elongation with the length of the entire stipe when the first measurement was taken, we find that elongation takes place throughout the entire length of the stipe until after it is 60 per cent. grown. From this time until ee Ree TPE ed ee wee coe ey She aed Ss a Bid oh as 4 " < q z 3 a 4 q y 1909] STREETER—DIRECTION OF GROWTH OF AMANITA 423 growth ceases, the zone of elongation becomes shorter and shorter, but is always just below the pileus. In the specimens used to make out the above table, the length of the mature stipe varied from 36 to 112™™, and the length of the zone of elongation varied from 2 70.407, Record was made of the amount of elongation which had taken place in each part of the stipe beginning at the pileus. By referring to the table it can be seen that in those plants which are about one- third grown or less, the zone of most rapid elongation is in about the middle of the stipe. As growth continues, this zone moves up the stipe. In plants which are half grown or larger, the zone of most vigorous growth is the second 2™™ from the tip. When the zone of elongation becomes less than 4™ in length, growth takes place in the upper 2™™ (see record for 123). The elongation within the upper 2™™ of the stipe is usually less than that within the second 2™™, but in some cases they are equal. The amount of elongation in each 2™™ becomes less and less from the point of most rapid growth toward the base, until the growing region is passed. : In order to determine the time element in the geotropic response of these toadstools, plants were placed in a horizontal position in the . dark and records of the amount of curvature were taken each hour. The following table gives the records of two of these specimens: No. 51 No. 56 Time igo Pe of Amount of an change ses change Position foreach Position tc back successive hour successive hour nh: Se SRA eae eer. °° or BAO A Me. cc ain s —4° —4° "a 5° RESO A. Meee cee ee ee =" Ss? og ic” BAS Ming coe ec ewe te ts 5 4° ar ee MAGA Moo vise cee he ee 8° 4° 32° 9° Wao Mok se tee ee tr” = 42° 10° EW sk ld woes ee re 4° 52 10° 00 SG ESSE aia ar rrae ar rar| 19° 4° 62° 10° ee Pe ee ee ce 22° is 2° 10° 3 3 ee POM ees es eS 24 2° 82° 10° Be eM ha hee oss Ace 20° 2° 88° 6° See PMA op eee 28° 2° 92° 4° es Mile = vain gees 30° 2° 95° ss a errr | 32° 2 97° 2 ee Ms ea is as 32° 0° + 98? ig Be A, Wee i Sa eee ws 32° 0° 98° 0° 424 BOTANICAL GAZETTE [DECEMBER In about two-thirds of all the plants placed in a horizontal posi- tion in these experiments, there was a bending downward of 1° to 6° during the first hour, before there was any observable upward curva- ture. This may be partly due to wilting caused by transplanting. In general this downward tendency was less in the younger specimens where the stipe is shorter, and it was less where the pileus had been removed. ‘These facts seem to indicate that it might be the physical effect of a new lateral strain rather than a response to a new stimulus. For this reason in many cases the pileus was removed, as is shown in jig. 4. No. 51 shows this bend downward in the first hour, followed by 1° more than complete recovery in the second hour. For the next six hours the rate of curvature fluctuated from 3° to 4° per hour; this was followed by a steady rate of 2° per hour for five hours; then the pileus came to rest at an angle of 32° from horizontal. In No. 56 the response during the first hour was slight; during the second it was greatly accelerated; this was followed by a period of depression which lasted for one or two hours; from this time on for the next five or six hours the reaction was constant and rapid, then more slow. After the vertical line was passed, the curvature took place more -and more slowly until, in the case cited here, it came to rest at an angle of 98° from its original position. Nine hours later, or 24 hours from the start, it remained in the same position and there had been no increase in length. There was no neutralization of the 8° of supra- curvature. In order to determine the exposure period, that is, the length of time which the plant must be stimulated in order that reaction may follow, several plants were kept in a fixed horizontal position for 15 minutes and were then rotated on a clinostat about the horizontal axis for 24 hours. The plants gave a decided reaction to geotropic stimulation for this length of time. There was an upward curvature of the stipe varying from 1 5° to 30° from its position during exposure to the stimulus. Four records of plants of A. phalloides, stimulated by being in a horizontal position for 5 minutes and rotated on Md clinostat for 24 hours, showed an upward curvature of 7°, 10°, et and 15°, respectively. Eight records of plants of both A. phalloides and A. crenulata stimulated for one minute all show an upward curvature of either 6° or 7°. In one case of stimulation for 5 minutes, aa ee a EE 1909] STREETER—-DIRECTION OF GROWTH OF AMANITA 425 in three cases of stimulation for one minute, and in all cases (ten records) where the specimens were in a horizontal position only 30 or I5 seconds, there was no direct upward curvature. Instead, the stipe had made a definite spiral curvature in the same direction as that in which the clinostat moved. Clinostats which rotated in opposite directions were used and the spiral always followed the direction of the clinostat (fig. 12). O find the latent period, the pileus was carefully removed that Curvature might not be retarded by the weight which would cause a Strain in an unusual place and the plants were placed in a horizontal position. Records were made every 10 minutes. In young, vigorously growing specimens, there was an up- ward curvature observable in 4o minutes. In other specimens which were nearer maturity, the period was longer, in some cases being 60 minutes. Fic. 12 Fic. 13 Fic. 12. A. phalloides: a, as placed on clinostat; 6, 24 hours later, showing Special curvature of stipe.—Fic. 13. A. phalloides, showing amount of curvature for €ach ro minutes for 80 minutes. No records which showed the downward bend were considered in this experiment. The diagram (jig. 73) shows the rate of curvature in a typical specimen. SUMMARY When young and vigorously growing toadstools were placed with the stipe in the horizontal position, the stipe of each toadstool bent and carried the pileus up to or beyond the horizontal position. This Supra-curvature when it occurred was neutralized if growth did not €€ase too soon. The responsive zone is situated near the tip of the stipe, not within the pileus. The stipe elongates throughout its entire length, until it is more 426 BOTANICAL GAZETTE [DECEMBER than half grown. The zone of most rapid elongation is always just below the pileus and becomes shorter and shorter until growth ceases. When placed in the horizontal position, the tip of the stipe curved upward very slowly at first, then more rapidly, until it passed the vertical position, after which the curvature took place more slowly until it came to rest. If growth were still vigorous, the tip of the stipe again passed the vertical, rested on the other side, and finally assumed the ordinary position. The amount of time which a toadstool must be stimulated in order that reaction may follow is less than a minute. How much less was not satisfactorily determined, probably because the clinostats used rotated too slowly. : The latent period varied from 40 to 60 minutes, the younger specl- mens responding more quickly. Jersry City, N. J. THE WILLIAMSONIAS OF THE MIXTECA ALTA G. R. WIELAND (WITH TEN FIGURES) The great plateau and mountain region in the central and western portion of the southern Mexican state of Oaxaca is commonly known in Mexico as the Mixteca alta, or high country of the Mixteca Indians. This name is used in contradistinction to the Mixteca baja, or portions of the lower country or tierra caliente over which the Mixtecas have extended. Simply speaking, then, the Mixteca alta is a portion of the southern edge of the Cordilleran system facing the Pacific and extending through western Oaxaca to the border of Guerrero, or into the latter state. Here, during some five months of the past winter and spring I have had the pleasure of continuing field work on the American fossil cycads under the auspices of the Instituto Geologico Nacional de Mexico. I have the kind permission of the director, Sefior AGUILERA, to note in this preliminary manner that the results obtained are regarded as of the greatest interest to paleobotanists. The field work has included the making of an accurate section through fully 2000 feet of plant beds of Rhit-Liassic age, full of cycads in as great a variety of types as has thus far been encountered anywhere in the world. Indeed, considering the fine material ob- tained from the localities noted in the valley of the Rio Nochixtlan hear Tlaxiaco, at Mixtepec on the Rio Tlaxiaco, notably all around the Mina Consuelo, about El Cerro del Lucero, and the Rosario region to the southwest of Tezoatlan, as well as elsewhere, and considering, Moreover, the almost endless opportunity for opening up quarries in all this extensive country, I am of the opinion that the Mixteca alta IS one of the most promising and accessible regions for the student of fossil plants yet discovered. True enough, these localities are distant from the railway 50 to 150 miles or more, over the roughest of mountain trails. And as Mountain succeeds mountain with scarce a valley between, there are Some real difficulties for the collector, who must send out his material in blocks of limited size, such as can be loaded on the backs of the 427] [Botanical Gazette, vol’ 48 * 428 BOTANICAL GAZETTE [DECEMBER tough little burros, or on the strongest mules, which can carry a pair of boxes of 200 pounds weight each. Hence, it more than once becomes necessary to break the splendid slabs all covered with leaf impressions, and often bearing flowers, which one can secure in even the smaller quarries almost without limit. But for a country so distant, there are many very distinct advan- tages and no final obstacles. Animals are trusty; the Indians are good and cheap workmen; one is everywhere met with great courtesy; it is a source of much interest to find the high degree of comfort to be had in some of the most distant of the towns and villages; the food is always good, and even in the far mountains one can always get eggs and tortillas. All in all, if one is only fairly fore-wise, to spend a winter in the sunshine, the forests, and amidst the grand scenery of the Mixteca alta is much more like enjoying oneself in some geological Sanatorium, as it were, than like-hard work. For the naturalist ever finds a thousand and one points of interest, and soon becomes accustomed to ride 20 to 50 miles a day as he may need; while if interested in the cycads he can find places farther _down the cafions and deep valleys where species of Dioon are fruiting hard by strata yielding the fossil forms in profusion. The great thickness of these Oaxacan plant beds has been noted; but as to their exact age I am not sure, it being as yet early to form a fair conclusion. Glossopteris, rather than merely the sage Pterids, is considered present; and there is also a wealth of taenio- pterids of older type, as well as a fine series of stems of a small but distinct lepidodendrid, and many leaves of Noeggerathiopsis Hislop Bunbury. But otherwise the facies is uppermost Triassic, if indeed Liassic genera may not in the end be found to preponderate. A similarity to the Gondwanas of India suggests itself. But what commands our attention at present, far beyond the precise age of these beds, is the fact that there abound in them In great variety the imprints, casts, and molds of many fruits of Wil liamsonia, closely associated with Zamites, Otozamites, Podozamites, Pterozamites, P tilophyllum, and Dictyozamites, fronds as well ae seeds. One of the strobili is a mold of just such an ovulate fruit as BUCKLAND figured under the name of Podocarya in the Bridgewater treatises, the original of which should be at Oxford, but could not be 1909] WIELAND—WILLIAMSONIAS OF MIXTECA ALTA 429 found when a search was made for it a few years since, as Professor SEWARD of Cambridge has informed me. Also, there is a con- siderable number of the large buds inclosed by heavy ramentum- covered bracts of the same size and appearance as those from the Yorkshire coast. One favorable circumstance that has conduced to frequent preservation of the surface characters of the ovulate fruits is the formation by the outer zone of a layer of coal, which while liable to checking affords an excellent indicator for which one may keep constant watch. Furthermore, the close association of these fruits, leaves, and stems, though the latter are not well preserved as a rule, leads to the hope that as the collections come to embrace a wider range of localities, and the data of association come to be better known, more than one restoration of the complete plant can be made. That silicified forms may yet be found is proven by the occurrence of a well-silicified log of a new species of Araucarioxylon. Especially interesting is the occurrence at Mixtepec on the Rio Tlaxiaco of fruits of small size borne on slender stems, and also those with broad bladelike bracts of thin texture, if they are not indeed Sepals or petals. These small fruits, while not preserved in finer details, are abundant, and are quite uniformly accompanied by Small, much-branched stems, and by numerous fronds no more than Io°™ in length; though these may have been bipinnate. Of primary importance is a single fairly well-preserved impression Of a staminate disk from midway up in the plant beds in the main barranca between El Cerro del Venado on the south and El Cerro del Lucero on the north, near the coal outcrops of Mina Consuelo, 15 miles from Tezoatlan. On my return from the Mixteca alta I supposed that I had not found any of the staminate organs of the cycadophytes; although various interesting fruits of seed ferns appeared to be present. But I found on my desk at the Instituto Geologico a letter from Professor NATHoRsT, dated from England and telling me that he had just visited the Yorkshire coast, where he had succeeded in finding the first definitely recognizable male flowers of Williamsonia, these agreeing essentially with the flower of Cycadeoidea as first discovered in the type of C. ingens and described in my Studies of American fossil cycads, parts I-IV. It can be readily understood that I had kept a sharp watch for 430 BOTANICAL GAZETTE [DECEMBER such disks during all the field work, and that after reading Professor NatuHorst’s letter this watch was made closer still while the various specimens were being unpacked, placed in order, and further developed. But not until all this work had been done did I finally, in an idle moment, uncover a staminate disk on a slab from near Mina Consuelo. Then I recognized that a form I had suspected at one time was a disk had been truly such, though poorly preserved. It seems I had not chanced on quite the best disk locality. Better localities will yet be found. . The El Consuelo Williamsonia staminate disk is a reduced cam- panulate form of the size and general structure indicated in jig. 2. As there shown, however, the number of fronds is arbitrarily taken for purposes of interpretation as five, instead of the true number of eight or ten. One cannot be quite sure of the exact number in the specimen. The important structural feature, however, is that instead of a bipinnate frond as in Cycadeoidea,' there is a small strictly once-pinnate form,. the rachises bearing only two lateral rows of synangia. These, however, are still of the marattiaceous or cycade- oidean size and structure. The component fronds project beyond the disk only to a height of about r.5°™, The basal region appears to be rather thin in texture ; but the state of preservation as well as the association with other fruits and leaves all go to indicate that these disks and doubtless those of other species and genera should yet be found in abundance. : There can be no gainsaying the supreme importance of this fossil flower in enabling us to form more exact and adequate conceptions of the course of evolution leading up to and resulting in the present diversity of gamopetalous plants. In describing the flowers of Cycadeoidea ingens and C, dacotensis, I pointed out that the disk type of cycadophytean flower clearly indicated previous stages with the staminate organs spirally inserted beneath an apical cone wie series of likewise spirally inserted megasporophylls, and that readily conceivable reductions and changes in such a primitively via inflorescence or fertile apex or branch fully indicated the mode st origin of Liriodendron. Whence it followed that the Magnoliaceae : ita s Sell ‘I followed the old usage of calling these fronds pinnate in my descrip ae a ARBER has called them bipinnate forms. It seems rather more correct so to a0. I if AT gog] WIELAND—WILLIAMSONIAS OF MIXTECA ALTA 431 os if not the most primitive of all the angiosperms. In pendentl vetoes ese: the first; though HALLIER soon inde- y reached similar conclusions as to the origin of the Magno- a and likewise cited Liriodendron. eco. and PARKIN visualized in the Annals oj botany the crown of i Gree co cadean angiosperm ancestor with its surmounted a ieee dase 5 irally inserted microsporophylls a. y similarly set carpophylls; and these authors at the etn tae much further the idea that the true mode of angio- all its broad eeaser long completely hidden, was at last indicated in 3 aes outlines by — direct evidence. a Racha and PARKIN Ss ancestral stage we certainly behold a a. and decidedly plastic type, which they choose to call under SE though I perversely prefer to group such plants hypothetic ae S old term of proangiosperm.’ It is one of the = orms, moreover, which is not only so readily conceivable . infinity of modifications in the direction of higher Blentiy : one which, as I have long since told ARBER, we may con- Sl will yet be found in the fossil stage. into th . ae this progress, the actual mode of modification leading re complex types of angiospermous flowers has remained grow “ : . Sa hemiangiosperms,” as he has proposed. I duly s of importance that they receive a more thorough consideration than can be accorded them here. should duly honor SAPORTA as psed an important truth when To claim that the proangio- . ae the angiosperms, could have their gymnos iid He ude other truly lineal families, Diane m the Cycadeoideae at best. For these reasons, at ae that to use fairly the term hemiangiosperm we farth ’ ere by another hiatus the proangiosperms merge into the more primitive fern derivatives. 432 BOTANICAL GAZETTE [DECEMBER obscure. While Scort, especially, as well as HALLrER, ARBER and PARKIN, BEssEy, and others, as well as myself, have all insistently urged that the path has thus really been blazed to a knowledge of the evolution of the angiosperm groups, no one has yet been ina position to bring the final methods more clearly into view. Now, however, I believe we can do so in the case of all but the extremely modified families, if not indeed ultimately in these too, by means of analogic methods combined with comparative morphology. We have seen how the staminate disk of Cycadeoidea ingens, and of all the other species so far known, bears inside the campanula or androecium many functional synangia on the raclhial axes, either inserted directly or on pinnules. Now we see, furthermore, that the campanula remains large in a form with greatly reduced fronds, while we may be sure that interiorly borne synangia are still present on the rachial axes, or at least may be in related forms, whether we can detect them or not. Whence it follows that a slight further continuance of the rachial reduction, so plainly under way, must result in a toothed campanula bearing interiorly on each axial or rachial line only a single pair of synangia and finally a single synan- gium and no more, just as diagrammatically shown in jig. 3. uch types we may call, because of the strictly convolvulaceous aspect, archaeosolandrous, arbitrarily dismissing for the present all mention of the central ovulate region to which we return below. Now plainly, having thus by a series of entirely simple stages reached this archaeosolandrous form, which we confidently believe will be detected in the fossil condition, it is only a minor step t0 simpler types of pollen sacs, either borne in pairs or singly, and finally to elongations of the filaments suiting the requirements of such flowers as that of jig. 4, which is none other than a common morning glory, In short, the successive members of the series of steps outlined are these, letting capitals represent the known, and small letters the hypothetical plants: A’, Proangiosperms, or hemiangiosperms and pteridosperms. Pee A. The flower of Cycadeoidea dacotensis, with a campanulate disk of 18 bipin nate members B. The flower of C. ingens, with 12 bipinnate members. 1909] WIELAND—WILLIAMSONIAS OF MIXTECA ALTA 433 C. The flower of C. Jenneyana, with only 1o bipinnate members, as well as - various other greatly reduced and small types of flowers of Cycadeoidea. A hypothetical flower of Cycadeoidea, with a staminate disk of 5 bipinnate members or staminate fronds (cf. jig. 1). Fics. 1-4 2 The El Consuelo staminate disk composed of 10 or 12 pinnate fronds. vy A derivative of the El Consuelo disk, with only five pinnate fronds forming the Campanula (cf. fig. 2). A hypothetical campanula derived from the preceding by reduction of the Synangial number to two and finally one, borne interiorly (fig. 3). 434 BOTANICAL GAZETTE [DECEMBER od Unknown intervening plants derived from g and undergoing reduction in the number of the sporangial loculi, with thinning of the synangial wall, or An unknown form much like g, but with a simpler type of pollinial organi- zation. (This is the more probable member of the direct series, but bot may be conceived of as having once existed.) A campanula derived from either # or i; in which reduction to the angio- spermous pollen sac has taken place, and in which elongation of the stami- neal pedicels or filaments is going on (cf. fig. 4). The staminate campanula of the conyolvulaceous and many other gamo- petalous flowers. =. =, 2 Thus may we derive the staminate zone of gamopetalous forms by a series of readily conceivable and closely united reduction stages, the principal members of which are in the larger sense already known. But let us now see if it be possible to go on and establish a plausible ovulate correlation; for if this cannot be done it is more than superfluous to say that K is in the extended sense not proven to be a true member of the evolutionary series A’, A-j. : That an apical series of spirally inserted carpophylls giving Tse to a central ovulate cone played the chief role in the development of the Magnoliaceae, as in all the conifers and doubtless many other forms, is evident enough. But that such a cone was in all cases organized, or much less that a terminal group of diffuse carpophylls was present in all the ancestral phyla of the angiosperms, is after a little consideration seen to be a cumbrous hypothesis. By what other means then than by the reduction of the carpophylls and of cones may we conceive of the cognate origin of the ovulate region in angiosperms? Perhaps the Draceneae may be made to give an initial anew: Take for instance the cultivated maguey (Agave) of Mexico, with its six immense versatile anthers borne on their long projecting filaments as seated in the interior surfaces of the six fused sporophylls, three of which are smaller, and the other three of which are alternately of larger size. On cutting this flower open and viewing it from the interior, is not the structure in reality that very diagrammatically indicated in fig. 5? Now, was not this floral structure derived from a cone and changing whorl of six primitive bisporangiate fronds with bass megaspores and apical microspores? The simple method of deriva- 1909] WIELAND—WILLIAMSONIAS OF MIXTECA ALTA 435 tion from such a primitive, or archaeo-amarillidaceous plant would consist in basi-lateral fusion of the sporophylls and development of a trilocular ovary, with the synchronous reduction and change of the microspore zone to the series of six interiorly borne stamens, after the manner shown to be feasible in the above series A’, Aj. Such Wwe conceive to have been the origin of the yuccas and agaves; for it is no more improbable that heterospory should in many primitive stocks arise thus regularly in each of an apical whorl of sporophylls, than that it should find expression in the Segregation of a basal group of megasporo- phylls followed by an apical group of micro- Sporophylls, as in Cycadeoidea. Evidently in Agave americana the last Stage of fusion resulted in the suppression of the basal or megaspore region of three alternate fronds. Nor is it so difficult to conceive how, the plant finding the inclosure of the ovarian region to its advantage, an elongation of the style finally resulted, with the retention of the gametophytes and seeds. Also, the long filaments must have been . very readily produced by the flower under the stress of impulses that had to do with } nothing else than the ordinary phenomena of fertilization. Such, Surely, are the conclusions one may reach from the macroscopic Xamination of flowers like Agave and perchance likewise of the Tose hip. While the manner of evolution just outlined is in reality not utterly different from that of the Magnoliaceae, the order in which the parts are segregated clearly indicates a remote separation of the several stocks involved, and therefore the virtual polyphyletic origin of the angiosperms. But of course, when the initial changes, and When the major or crucial changes leading up to the two groups now Considered so briefly, took place, and which group is in reality the More ancient, are questions that only the future may answer. Having seen that the ovulate region, whether locular or strobilar, and whether there are few or many ovules, offers no impassable 436 BOTANICAL GAZETTE [DECEMBER hiatus, it becomes desirable to interpret a few more examples of staminate organization leading toward or into the more complex types of flowers. Thus may we best test our theory and see if it applies to petals and stamens generally, and really affords a far- reaching explanation of floral constitution in the angiosperms, with ultimately a better basis of classification. But in so doing we may only take up a few forms; for an exhaustive analysis of the families based on the necessary histological and developmental data must be a truly gigantic task for many years and many workers. Various gamopetalous flowers have the structure shown in fig. 6. Apparently the stamens alternate with the lobes of the corolla in b Fics. 6-8 such forms; but on closer examination it is seen that in reality the axis of the component leaves has shortened to form the notches. This difference, so convenient in classification, therefore rests on very slight anatomical distinction, unless it can be found to accom: pany a particular juxtaposition of the ovules throughout the groups question. My example is from a shrub I found growing on the slopes of Popocatepetl, though anyone may turn to Gerardia and Pentstemon as equally good examples of this type of androecium. Again, the cruciform flower invites attention, whether it be regarded as an approach toward or a departure from distinctly gamopetalous types. For in the cruciferous flower, although the stamen is appat ently inserted on the common receptacle, rather than as in the dia- gtammatic fig. 7, there is considerable doubt if it is to be regarded as of discrete origin. Instead, it would seem more probable that 1909] WIELAND—WILLIAMSONIAS OF MIXTECA ALTA 437 although the point of stamineal attachment has become strongly depressed and indeed is virtually basal now, the flower has arisen very similarly to that shown in fig. 4. The two single stamens alternating with the two pairs thus form an opposing analogy to the Suppression of megaspore regions in the Agave. But.other explana- tions are also possible. For we believe that in the angiosperms petals have developed from bracts, that they have resulted from the complete sterilization of sporophylls, and that, as explained above, they result in vast numbers of instances from the apical expansion of a sporophyll, which, though greatly reduced, may still bear either Megaspores or microspores or both.s And furthermore, we regard the stamens of Liriodendron as final reduction stages of individual sporophylls that were once large. Of further interest in the cruciferous flower is the fact that little or no difference in the development of the petals accompanies the Staminate change. But, on the contrary, in the diagram of a honey- suckle (jig. 8), while the stamens are of normal number and size, 3 There also appear to be various instances of more or less completely salver- shaped corollas, in which what are usually called the sepals are in reality fertile or; alternate with the petals, between which they press and fuse up to the beginning of the lobes of the corolla, and there bear stamens just as do the petals. Take for instance those forms with four “sepals,” four petals, and eight stamens borne four on the petals and four alternately between them, but plainly scaling off with the members of the calyx. The cherry (fig. 9 from GRayY) xa t one retaining more stamens, these not being so distinctly determinate in number. (They may be of the inner row.) Perhaps as great a difficulty as we meet with discrete hypogynous stamens and a free multiovulate ovary with an apparently distinct axial relation, for here there are several pos- sibilities. Naturally that first coming to mind is that of a central carpellary whorl, followed below by a staminate whorl, and then by the members of the floral envelope. But another method needs to be reckoned with, namely, that which may be seszind characterized as a completed supero-axial shortening and consolidation of the bi- Sporangiate fronds of an apical whorl, in such manner J Pinnules assumed a vertical position and fused to form the ovary, style, and stigma, While the more apical microspore regions of these same fronds produced the stamens, the frond tips finally forming the corolla. 438 BOTANICAL GAZETTE - [DECEMBER the members of the corolla undergo division into a major and minor group. And plainly, from these simple phases we may no doubt ultimately pass by as simple steps and combinations to a reasonable interpretation of all the multifarious reductions, ‘suppressions, and alterations in first one set of organs, and then another, resulting in papilionaceous, orchidaceous, and all the manifold forms of angio- spermous flowers. It is obviously not feasible adequately to show the derivation and the complex relations of sporophylls leading from the primitive to the higher types in any simple manner. Above all is this true because of the necessity of taking into account the varied possibilities and phases of monoecism and dioecism in any even approximately com- plete presentation. And the different rates of reduction at different periods, we are bound to assume, further complicate the problem. Indeed no one diagram and no one set. of diagrams would serve to outline adequately the changes now suggested. Nevertheless, the attempt is made in jig. 10 to give the simplest and most abbreviated expression of sporophyll change possible. Have not the transformations really been easier than we think? Dictyozamites, the net-veined cycad, and many net-veined ferns of which some were doubtless seed-bearing, together with the forms of unknown fruit like Cissites, Vitiphyllum, and Liriodendropsis, all go to show that there is no special hiatus between the angiospermous foliage and the more primitive seed-bearing plants. A single new locality in the upper Triassic or lower Jurassic may at any time com- pletely close the foliage gap. Again, the stem structure of the ang: sperms presents no difficulty of derivation from the older types, which free branching is already known, as well as the presence of numerous flowers undergoing great reductions and changes. The great double funnels of the near-by Ipomoea, nearly a foot in length, show how readily fusions-have gone on, and how great must have been the changes, reactions, and alterations going on for ages in all floral organs. The balance once disturbed, or a critical stage or plastic form once accomplished, infinite changes in a truly polyphyletic race set in. ar Other fossil evidence for metamorphosis and reduction will be forthcoming, and speedily. But the student of fossils now realizes ” 1909] WIELAND—WILLIAMSONIAS OF MIXTECA ALTA 439 ae fg To. BS Boat Siacrine and actual sei a the See of ee pothetical homosporous fronds. "8, heterosporous pteridophyte 4,h dices Romosporous ear 7 pteridophy tes pines: a ; an prey of B (Permian; Cycas); BY”, staminate derivative of B etalous angiosperms; D, fu rther all the essential organs and parts carpel, stamen, petal, a and sepal C, reduced form of B and a "progenitor of famop reduction stage of C, with, seenaath of giving r a pet tfect flow ee pee stamino-petal ‘D"; greed derived from BF a, true ca pitlalers carpellary leaf; b, reduced carpellary leaf; I, true a frond (Williropen ESO - sa leading to gamo- reduc rue stamino-petal; 4, c, pedicellate ovule or seed rms;. 2,°tr Gr 3’, a7 ’, second method a sepa petals iets Cyca We Shih AD xEs.—B’ + B” (I-IV) =Co ectatta)et; Coniferales, Ginkgoales, Ma, et A+C Vi Cra raat many proangiosperms; A’'+C (VD= Cc agg laceae, Liriodendropsis, etc.; C (VIl)=many types of naked cg ictal spe (VIII) =gamopetalous a gee ae forms; eae =many a t™ms; A +a=proangiospe 440 BOTANICAL GAZETTE [DECEMBER that the proangiospermous or hemiangiospermous plant types which will exhibit critical developmental phases are likely to be inconspicuous, and that they must be studied with extreme care. Our hypothetical archaeosolandrous type, for instance, could be very easily missed, though found in excellent preservation. It will be necessary for that fortunate collector who finds the horizon and locality with lineal members of the early angiosperm line imbedded in it, to apply to his material all the newer laboratory methods, namely: (1) the staining, imbedding, and sectioning method used by JEFFREY and Ho ttick in dealing with forms apparently more like impressions or carbonaceous material than the partly preserved structures such as they finally found; (2) the developmental method, by means of which BEECHER showed the preservation of the most delicate trilobite structures, and won such clear results; (3) the collodion method of NatHorst for recovering microscopic surface details, which are often present. ‘That intermediate types will be found in increasing number can- not be an idle prediction. That from tinie to time there will be found types definitely hypothesized, may be hopefully expected. Ten years ago I predicted the discovery of the seed ferns, now known in such number and variety. Even then it had become clear that “progressive prothallial elimination with correlated spore differentia- tion and alteration of the frondlike sporophytes of primitive ferns of the marattiaceous or an allied group were the basal factors in the evolution of the cycadofilicinean and cordaitean alliance.” And it already seemed probable that the angiosperms could be added in this statement. At the present time these groups seem to present more and more distinct points of contact, though in a very complex manner, oer ently calling into requisition nearly every thinkable modification of the monosporangiate and bisporangiate frond, both on the same and on separate axes, and with nearly every conceivable variety of os arrangement, reduction, sterilization, and suppression. Even m the Cycadales, the better known of which form a really compact group, we have been compelled to say that the orders “do not appear “ have passed through precisely the same. evolutionary sae tones . heterospory, bisporangiate or monosporangiate, monoecious, 42 finally doecious fructification.” 1909] WIELAND—WILLIAMSONIAS OF MIXTECA ALTA 441 And once more, we are compelled to hypothesize an extensive and far-reaching polyphyly for the angiosperms. But, none the less, the thought is also present that once an approach has been made along all the available lines of evidence, this seeming maze of possi- bilities may in the end be found vastly simpler than one can now Picture. At least we are already persuaded that the day will come when the true relationships and derivation of every angiospermous family will be worked out and satisfactorily stated with mathematical precision. EL Instiruto GEoLocico NACIONAL MEXICO SAP PRESSURE IN 'THE BIRCH STEM “PART I H. E. MERWIN AND HowaARD LYON (WITH FIVE FIGURES) During the seasons of 1902 to 1904 sap pressure observations were made on several kinds of trees in the vicinity of Oneonta, in central New York. Birches and maples illustrate the two extreme types of sap pressure phenomena. Our observations on the maples are in accord with those of other observers, especially as set forth by JONEs, Epson, and Morse.' Sap pressure in the birches has not been studied much hitherto, except as incidental to other studies. We found that glass tubes of small bore filled with mercury made very sensitive pressure gauges, especially if the tap hole in the tree and the connecting tubes were filled with water or sap when the gauge was attached. When pressure was negative (suction), a bulb tube was sometimes arranged to allow water to flow into the tap hole, and to catch the gas which escaped. Gas in the tap hole when pressure is negative causes disturbing capillary effects. Gas in the tubes has a damping influence upon the gauge. Characteristics of sap pressure in the birches No sap will flow from tap holes in the stem of the birch or ooze from cut twigs till the ground has thawed considerably in the spring. It is not necessary, however, that the air temperature be continuously above the freezing point before pressure becomes high. From April 5 to April 22, 1904, we have recorded seven nights in which the tempera- ture was below freezing; yet on April 5 a positive tension of 44.3°™ was observed in a yellow birch (Betula lutea); April 9, 87°™ in a black birch (Betula lenta); April 18, 3 5°™ ina black birch. F reezing nights were often accompanied by negative pressure which was maintained for a few hours after sunrise. The maximum pressure comes about a month after the first decided appearance of pressure. The buds by this later time have begun to unfold.. There is at all 1 Jones, C. H., Epson, A. W., anD Morse, W. J., The maple sap flow. Vt. Agric. Exper. Sta. Bull. 103. 1903. Botanical Gazette, vol. 48] L442 /0 Ta a, a e we i i s HH. a aes Pad -o 4 SoS cm / - ae —Sap pressure curves for maples and birches April 18, 1904: A, near the base of a 12-inch maple; B, 157°™ above A; C, the Ma anit D, 180c from the base of 7-inch black birch; F, 135° below D; E shows where the pressure curve of D would have been if there had been exact hydrostatic equilibrium within the tree; G, curve for a 10° maple; the responses of pressure to sun- shine and cloud are to be noted [6061 ftv HONId AHL NI AMASSAAd dVS—NOAT GNV NIMYIW 444 BOTANICAL GAZETTE [DECEMBER times a very regular distribution of pressure in the birch trunk, taps at the same height giving like pressures, and taps at different heights showing most pressure in the lowest. The difference between the pressure in the lowest tap hole and that in the highest is usually slightly greater than the hydrostatic difference in level between the holes (fig. 1). Pressure in one hole is always immediately and markedly lowered by sap flowing freely from another hole, even though the holes are on opposite sides of the tree and many feet apart vertically. This fact, of course, indicates a free intercommunication among the ducts of the birch wood. ; In all of the cases we have observed, pressure began to be evident at the base of the tree first, and as pressure increased there it showed itself higher and higher up. Daily fluctuations of pressure in the birch were reported by CLARK.’ The general character of these fluctuations was brought out by sen) observations in April 1904. A rapid rise of pressure beginning In the morning is followed by a slow decline till near sunset, then a gradual rise is kept up during the night. The nightly rise of pressure is checked if the temperature of the tree falls below freezing. Changes of pressure are only slight the next day after a freezing night, unless the air temperature reaches 40° to 45° F.ormore. (These oscillations of pressure occupying a period of a day are graphically shown in jig. 3 of the second part of this paper.) ey The most striking phenomenon of the birch sap pressure is its variability during those rapid changes of sunshine that take place on days when cumulus clouds occasionally drift before the sun. ya have seen the mercury column in a gauge move more than 2-5 vertically in a minute in response to a change of less than 1°C. as registered by a blackened-bulb thermometer exposed to the sun- Furthermore, pressure changes of this rapidity have been kept up. for nearly ten minutes at a time. Fig. 2 is a record for part of an afternoon in which bright sunshine and dense cloud-shadow - nated. A drop in pressure of 37-5°™ of mercury during a period © cloud-shadow, and a subsequent rise of 30°" when the sun appeared, took place between 2:30 and 3:20 p.m. A comparison of the bir ? CLarK, W. S., The circulation of sap in plants. 1874. 1909] MERWIN AND LYON—SAP PRESSURE IN THE BIRCH 445 with the maple, in respect to pressure and the passing of clouds, may be made from jig. r. Even the most decided ups and downs in the _ curve of the birch pressure are scarcely more than suggested by the slight steepenings or flattenings in the long slopes of the maple curve. e have always found the maximum pressures in large birches higher than in small ones. The highest pressures observed in both large and small trees were on May 2, 1904. A 7.5°™ black birch then gave a record of g1°™ (1.2 atmospheres), a 17.5°™ black birch of 146°™ (1.9 atmos- pmrzo 2:00 2:40 320 4:00 4:40 Pheres), and a 35°™ = black birch, about 20™ — Z high, the astonishing pressure of 204° V/\ hy ae (2.68 atmospheres). x The last pressure would doubtless have 70 been even greater if it had been taken two hours earlier, for both Pr = he 7. 5°". and « the 17.5°" trees had ) rt Adi ‘Al already declined more : than ro per cent. from EY maximum when the : large tree was tap ped. Fic. 2.—The intensity of the sunshine as measured As it is, this pressure by a blackened-bulb thermometer and the concurrent is equal to 200°™ of pressure, measured in inches of mercury, at the base of mercury or 27™ of a 35°™ black birch, May 2, 1904. water, being 1.8™ of water higher than any previously recorded sap pressure (CLARK, /.c.) Such pressure would support a column of water 7.8™ higher than the tree. The highest point on the pres- sure curve of jig. 2 represents this pressure. Negative tensions occur frequently in the higher parts of the trunk of the birch, and less frequently near the base. In the latter position it is only in the early part of the season that suction is kept up for more than a few minutes at a time. On April 22, 1904, suction pre- vailed all day in yellow and black birches that had been in states of 446 BOTANICAL GAZETTE [DECEMBER high pressure on several occasions since April 5. A hard freeze the night before and a temperature not exceeding 40°F. during the day seem to have been the chief factors controlling the negative pressure. The chief characteristics of sap pressure in the maple On some warm winter days, at least as early as February 1, sap will flow in amounts of a few cubic centimeters from tap holes in small maples that are exposed to the sun; but the maximum flow and cor- responding pressure do not occur till the ground is thawing in the spring. At this time pressures in a tree are not distributed with any apparent regularity. Portions of the trunk at the same level may give very different pressures, and for different heights the pressure may be greatest in either the highest or the lowest situation, though usually pressure decreases irregularly with height (fig. 1, A and B). Pressure in one tap hole may be but little decreased by sap flowing freely from another hole a few inches at one side of it, but there may be a decided drop in pressure if the flow is from a hole a few feet above or below the hole to which the gauge is attached. From these facts it may be inferred that the ducts of the maple communicate with some freedom along the grain of the wood, but scarcely at all across the grain: | When pressure begins it may be manifest first either near the ree or in the branches, but for any given place in the trunk there 15 @ strong tendency toward a daily increase of pressure during the morning hours, and a decrease during the afternoon. The decrease often goes beyond zero to a considerable suction (fig. 1, B; after T:00 P.M.). Size of the tree, situation, and depth of tapping all affect the character of the daily pressure variation. Small size, €xposure to the sun, and shallow tapping are all favorable to extreme and rapid pressure changes. In spite of all the variations already discussed, there is a tendency toward parallelism of the pressures developed in different parts of the same tree, and in various tee during a daily period. The causes of such pressure variations, 4 related especially to daily periods of temperature change, have beet discussed by various writers. There is a general agreement that rises and falls of temperature 1909] MERWIN AND LYON—SAP PRESSURE IN THE BIRCH 447 of a few minutes’ duration have almost no effect upon pressure in the maple. The Vermont Bulletin records one instance when a wavy line given by a recording gauge was probably due to variations in sunlight, pressure falling slightly when a cloud obscured the sun. Our record of April 18, 1904, shows conclusively that maples may respond notably to variations in sunlight. In fig. 1, lines A, B, G are pressure curves for maples. At 11 A.M. and at 2:00 and 3:35 P.M. the irregularities in the curves were observed to be directly related to insolation. As to the amount of tension that has been observed in maples, our highest records were from a'25°™ tree March 12, 1902, 75°", and from a 10°™ tree April 5, 1904, 69°". The Vermont Bulletin (p. 75) records a pressure equal to 129°" on March 21, 1898. Pressures exceeding 75°™ are only occasionally observed. Negative pressures seldom exceed 20°". PART II H. E. MERWIN Causes of sap pressure variations in the birches The studies of Ig06—1908 were carried on in Cambridge, Mass., in the hope of getting more data as to the causes of pressure variations in birches. The character of both the long and the short period oscillations on the pressure curve, and the corresponding record of a freely exposed blackened-bulb thermometer for several days, are shown in fig. 3. Several important relations are to be noted between the two curves. During the day there is a close parallelism; at night the pressure curve rises regardless of temperature. In other words, maximum pressure and maximum insolation occur at about the same time, near the middle of the day; but minimum pressure comes near sunset, while minimum temperature is nearly 12 hours later, shortly before sunrise. Some of the factors in the control of sap pressure are brought out in the several experiments and discussions that follow. The details of the longer experiments referred to in the general discussion are given under a later heading, Experiment shows that during the sap season for the birch, all the intercommunicating cavities of the roots and stem are kept Practically full of sap. One tree (exp. 1) gave the calculated gas — —— ai Sst Sy LA a 1s PMA pt j Pa Ae a ‘ i NV ae KE i [ / iS 7 2 ee Z a ] as = a 45 — : 35 Fic, 3.—The upper curves are the records of pressure in a white birch t1e™ in diameter; the continuous line covers the period April eas, inclusive, 1906; and the dotted lines A, B, C, D are partial records for April 14, 23, 28, 30 respectively; after April 18 the pressure was somewhat lower than it would otherwise have been, owing to a continuous slight flow of sap from the tree; the lower curves are temperatures in the sun; M, midnight; N, noon. gtr ALLAZVID TYOINVLOG aaawaoad] 1909] MERWIN AND LYON—SAP PRESSURE IN THE BIRCH 449 content of the vessels as about 1 per cent. of the total volume of the vessels. This fact easily explains the state of hydrostatic equilibrium which observation shows to exist in the birch stem when pressures are high. Increasing pressure must diminish the size of gas bubbles to a considerable extent by increasing the solubility of the gas in the sap; decreasing pressure would have an opposite effect. There is, however, until rather late in the sap season, a good deal of gas in the closed cavities of the wood fibers. This is shown by specific gravity tests. A density of 1 is not attained in the wood of the branches until the buds are about one-third longer than in their winter condition. The maximum density of 1.14 to 1.17 is reached when the first leaves are about 8™™ long, near the end of the sap season. About a month is required for an increase of 25 per cent. in density. Therefore, the aerial parts of the tree considered in exp. 1, with an estimated volume of 57,000°°, would require about 500°° of water as a daily supply from the roots to bring about this increase in density. | To get an idea of the amount of water required to maintain evapora- tion from a tree at the middle of the sap season, two twigs, weighing T.94°™ and 2.3556%™ respectively, after the cut ends had been sealed with balsam were exposed for 3 hours, the first to a temperature of 70° F. in the laboratory, the second to about 42° F. in a breeze. The first twig lost o.03812™, and the second 0.0256". An average evaporation of o.o1®™ per hour for a twig weighing 2®™ may be taken, therefore, as an approximate measure of evaporation from the birch for the middle of the sap season. The tree of the experiment bore about 2000 such twigs, from which the evaporation at this rate would be 480°° of water per day. This water evaporated from the tree and that absorbed by the wood fibers during the increase of density of the tree may be taken as the approximate amount of water supplied to the tree daily by root absorption. Inasmuch as pressures are freely transmitted throughout the birch stem, it is evident that variations in the rate of evaporation and ‘™filiration and of root absorption> will cause variations in pressure. 3 LivIncston (The réle of diffusion and osmotic pressure in plants. 1903) has the factors concerned in the control of absorption and pressure in roots. 450 BOTANICAL GAZETTE [DECEMBER It is needless to enumerate the weather conditions which affect the rate of evaporation, but it is worth while to note at least one chief factor in the control of root absorption. It is well known that root absorption is accelerated by moderate increase of ground temperature above the freezing point. It has been shown by MacDoucats that ground temperatures in the vicinity of New York City at a depth of 30%" are maximum about 8:00 to 11:00 at night, and minimum about 8:00 to 10:00 in the morning. At greater depths the maximum and minimum would occur later, but the temperature variations would be less marked. Therefore the maximum temperature of the roots of birches—which lie mostly within less than 60°™ of the surface of the ground—must occur during the night, and the minimum tempera- ture during the afternoon. Thus, root absorption and the pressure produced by it tend to increase at night. In Ciark’s (I. c.) experi- ments on roots severed from the tree, the rule was for root pressure to increase during the night and decrease during the day, for the whole period in which pressure was strong. ; Taking the combined effect at night of increasing root absorption and decreased evaporation, there is a decided tendency toward an increase of pressure in the stem during the night. As the pressure increases the rate of infiltration also increases, tending thus to dimin- ish the rate of increase of pressure (fig. 3). After sunrise evaporation begins to oppose the rise of pressure, so that about noon prey begins to decline. The decreasing activity of the roots at this time aids the decline. What pressure might be developed in a birch stem by the prolonged action of root pressure, if the modifying influences of evaporation and infiltration could be eliminated, is shown by C1ark’s record of 193°™ pressure in a birch root severed from the stem. This pressure is more than double the pressures usually observed in the trunk. - Assuming that root pressure is essentially osmotic, the concentra- tion of the sap in the root CLARK observed must have been about two and a half times that of the sap at the bases of trees I have observed. At different times during the sap season, I have evaporated sap ai birches and found it to contain o. 5 to 1 per cent. of solids, largely s ther 4MacDoveat, D. T., Soil temperatures and vegetation. Monthly Wea Review 31:no. 8. 1903. 1909} MERWIN AND LYON—SAP PRESSURE IN THE BIRCH 451 glucose. A sap containing o.8 per cent. of glucose represents an osmotic pressure of about 78°™ at o° C. It follows, then, that roo°™ of pressure in a birch stem is the maximum to be expected from root pressure. Volume changes in the sap and wood due to changes of temperature in the tree cause marked variations in pressure. I find that the expansion of sap from 6° to 32° C. is only 2 per cent. greater than the expansion of water. Cell wall substance, on the other hand, when saturated with water, expands about 2.2 times as much as water between 6° and 32°C. (exp. 3). Observations as to the elasticity to the transmission of light of birch wood tissue in a thin microscopic section shows that wood fibers and the walls of the vessels in the wood have the least elasticity parallel to the length of the stem, and that the medullary rays have least elasticity along radii of the stem. In a wood fiber the greatest elasticity is perpendicular to the surface. By comparison with other substances, in which expansion by heat is directly related to elasticity to light, a different coefficient of thermal expansion for different directions would be expected in both single wood fibers and in masses of wood. My determinations made on strips of green white birch wood about 500°™ long immersed in water show that between 6° and 32° C, there is contraction instead of expansion in a radial direction when the temperature is raised. Under like conditions a longitudinal strip showed at first a slight expansion, but in two subsequent deter- minations it contracted. The coefficients of radial contraction obtained were 0.000005, 0.000004, and 0.000006; and those of Jongitudinal contraction were 0.000002 and 0.000003. These coefficients are so extremely small that they may be neglected in the following sap pressure calculations.5 It thus appears that the volume changes in the cell walls above mentioned are made possible only by a diminution of the area of cross-section of the vessels and of the cavities in the cells, for the external dimensions of the tree change Scarcely at all. The effect of this tendency to diminish the pore space in the wood ’ The thermal expansion—based upon exp. 3 and upon the above coefficients— of a given volume of birch wood, of which 4o-45 per cent. is saturated cell wall, amounts ‘6 about 1.5 times the expansion of an equal volume of water. 452 BOTANICAL GAZETTE [DECEMBER is to produce pressure on the liquid or gas occupying the pores. If liquid alone completely filled the cavities of the wood, any amount of thermal expansion would necessarily be accompanied by an equal amount of elastic expansion of the wood. Pressure in this case might be very great. It should be noted, however, that the pressure recorded by a gauge would be less than that developed in the tree without the attached gauge, for the sap forced from the tree into the gauge would partly relieve the pressure within the tree. It follows that the less the amount of sap required to operate a pressure gauge, the higher the pressure it will record for a given amount of thermal expansion within the tree. It probably never happens that the wood of a birch tree becomes completely saturated with water. One or two per cent., at least, of gas is present in the wood fibers when the wood is densést. A smaller amount is present in the vessels. The compressibility of this gas lessens the effect of thermal expansion in producing pressure. In order to obtain a quantitative statement of the amount of thermal expansion, I have made the following estimates. The small white birch (11°™ diameter) of exp. 1 has about ro per cent. of its volume in small branches and twigs. These must vary in temperature in the same way that a blackened-bulb thermometer would, only in a less degree—say a maximum daily range of 20°C. The trunk would vary less in temperature than the air—say 10°C. The maximum daily change of volume of the sap and cell walls of the tree computed on this basis would be 270°°, or nearly o.5 per cent. of the volume of the tree. Under such conditions the presence of as little as T Pet cent. of gas in the vessels would prevent an existing small pressure from rising more than about 4o°™. The slight increase of pressure due to the greater expansive force of the gas at the higher temperature is so small that it may be disregarded. We may now consider in detail some of the instances 17 5 temperature controls pressure by causing volume changes within the tree. Fig. 2 is a record of pressure, and of temperature as given by a blackened-bulb thermometer. The periods of lower temperature were caused by the passing of clouds. Pressure increased during the periods of sunshine and diminished during the intervals of shadow- From 3:00 to 3:20, while the sun shone bright, the temperature of the in which 19099] MERWIN AND LYON—SAP PRESSURE IN THE BIRCH 453 thermometer increased 7° C. The corresponding increase in pressure was 30°". It is impossible that any part of the tree except the smallest twigs could have been heated during so short a time more than 3 or 4°. There must have been, therefore, little or no gas in the vessels of the tree. On April 21, 1906, from 2:00 to 2:45 P. M. (fig. 3), a rise of tempera- ture of 4°5 C. was accompanied by an increase of pressure of 20°". At sunrise on each of the mornings included in jig. 3 the pressure curves steepen greatly. During the afternoon of April 23, 1906 (curve B, fig. 3), the pressure was rising slowly till nearly sunset in response to a change of the weather with rising temperature. From the foregoing discussions it may be reasonably inferred that there are two chief pressure-producing agencies concerned in the phenomenon of sap pressure in the birch stem, namely root pressure and thermal expansion. The effects of both are modified consider- ably by evaporation and by infiltration of sap into the wood cells. . Root pressure and evaporation produce a daily oscillation of pressure, with the maximum shortly after sunrise and the minimum at sunset. Thermal volume changes in the tree cause a rise of pressure from sunrise till shortly after midday, and a fall from then till sunrise. Irregular minor oscillations of short period are caused by correspond- ing changes in air temperature or brightness of sunshine. The com- bined effect of the two agencies is to make the observed maximum come about midday and the minimum at sunset. The maximum is somewhat higher than would be produced by root pressure alone— in extreme cases twice as high. If a tree is tapped when the pressure is high, the flow of sap is at first copious, but the rate of flow lessens rapidly. The pressure, as measured anywhere in the trunk, also declines (see exp. 2 and fig. 5). The relation of pressure to flow during this period of falling is different for different relative positions of the gauge and the flowing orifice. Taking a theoretical case, the pressure as distributed over a radial section of a tree before tapping is represented in A, fig. 4. Lines of equal pressure are horizontal, and pressure increases downward. Shortly after tapping at a, the lines of equal pressure are as shown in B. A little later they are as in C. (The diagrams are constructed 454 BOTANICAL GAZETTE [DECEMBER for a case in which the resistance to flow of sap is twice as great radially as longitudinally.) Now let the rate of flow for the first ten minutes after tapping be represented by jig. 4, D, curve N, and let B show the distribution of pressure at the end of two minutes, and C at the end of the 10 minutes. Let the pressure be measured at the three points x, y, z. The pres- sure in x before tapping is 40.5°™, at the end of 2 minutes it is 35°", and at the end of ro minutes it is 25°". These values are plotted in fig. 4, D, curve X. The values for the pressure in holes y and z are likewise plotted in fig. 4, D, curves Y and Z. Inspection of these 0 88 Ke] SE | 0 40 Na —___ md : og 40 eae | X hea Ss Bs Fic. 4.—For explanation see text. 20 NP N ~ a So T { ! ! oO 1 ' / é Ss + —~~_ J N Pp ; A B curves of pressure and the curve of flow shows that there is no definite general relation between pressure and flow. Experiments EXPERIMENT 1.—During the evening of April 14, 1906, while the normal evening rise of pressure was in progress, a white birch (Betula populijolia) 11°™ in diameter and 6™ high was tapped for two gauge 157°" vertically apart. The pressure from the first was more bea enough to sustain a column of water as high as the tree. The differ- ence in pressure of the two gauges was 12 to 12.3°™ of mercury; the hydrostatic pressure corresponding to this difference in the height of the two gauges being 11.6°™, This hydrostatic equilibrium may be explained on the supposition that a practically continuous column of water could have been traced through at least some of the ducts between the tap holes. Other ducts might have contained bubbles mn.2 4 6 8 10 1909] MERWIN AND LYON—SAP PRESSURE IN THE BIRCH 455 of gas. That there was a small amount of gas present was shown by pouring mercury into the free arm of the lower gauge and thereby forcing back into-the tree 0.45°° of sap. This procedure caused the pressure within the tree to go up from 54 to 55.3°™. A simple calcu- lation shows that there was a contraction of nearly x per cent. in the gas in the vessels. The total volume of gas contracting was then 45°°. To get an estimate of the amount of duct space in the tree, I examined several cross-sections of branches about 2.5°™ in diameter. An area of 1. 25° ™™ contained an average of 74 ducts, with an average cross-section of o.002°™™, The ducts, therefore, occupy about — 12 per cent. of the volume of the tree. The volume of the tree (esti- mating the upper 3™ of the stem and branches as equal to the lower 3™ of the trunk) was 57,000°°. The duct space, then, amounted to about 6800°°. Finally, 45°° (the gas content of the ducts) is nearly 0.7 per cent. of the volume of the ducts. A second addition of mer- cury gave the gas content as 1.3 per cent. The ducts, therefore, at this time of the year were almost entirely filled with water. In a larger tree, in which there is a good deal of heart wood, there might be considerably more gas in the ducts, but many of the ducts in the heart wood are probably not freely communicating with the ducts in the sap wood. ; It was noticed in connection with adding the mercury to the gauge, that after the rise of pressure thus produced had taken place, the pressure remained stationary for 15 minutes the first time, and for 30 minutes the second time, and then began rising at its previous rate. Furthermore, the length of time that pressure was stationary was such that during that time pressure would have increased naturally the same amount that it was artificially raised. We may conclude from this that the intensity of root pressure was increasing during the night. This is in accord with the idea that the concentration of the sap in the roots—and the corresponding osmotic pressure—becomes greater when evaporation from the branches lessens. EXPERIMENT 2.—Before sunrise April 16, 1906, when pressure was high and slowly rising, three holes were bored in a small birch trunk, about 1.5™ apart vertically. Gauges were attached to the lower holes and the upper one was plugged. Equilibrium was soon estab- lished between the gauges, the upper one reading 61.9°™ and the 456 BOTANICAL GAZETTE [DECEMBER lower one 76.3°™.. The difference (14.4°™) is 2.8°™ more than the pressure of the sap column between the holes. This is the condition that would obtain if sap were being artificially pumped into the base of the stem and were evaporating slowly from the top. Friction of the sap in the ducts would cause the lower gauge to read higher than if no current were flowing. The gauge in the middle hole was then removed ‘and the sap allowed to flow from the hole. A few minutes later the upper hole was unstopped, but no sap flowed from it, though sap had flowed from it when the hole was made. The flowing of the hole below it had caused it to cease to flow. As soon as the middle hole began flowing, the pressure in the lower hole dropped rapidly to 23.4°™, and there remained nearly stationary for over an hour. The total drop in pressure in the lower hole was thus 52.9°™, but in the hole above the drop was 61.9°™. In other words, the pressure in the lower hole was 11.8°™ more than enough to raise sap to the level of the flowing hole. This, also, is a condition to be expected if a current of sap was flowing upward from the roots through the stem, overcoming friction. The flow from the middle hole was at first rapid—z7 drops in ro seconds—but it decreased in a few minutes to 8 drops per 10 seconds, and at the end of 20 minutes to 4 drops. The flow then - continued at nearly this rate for more than an hour. Curves 4 and B, D and E, of jig. 5 are plotted from these observations. Curve C shows the drop of pressure from a similar experiment on another tree. Although the curves are nearly parallel, the ratio of flow to pressure 1s greater for the highest pressure than for the lowest. This relation may be explained by assuming that the copious flow of the first few minutes had a double source of supply; the larger part came irom the trunk, being forced toward the tap hole by the elastic expansion of the wood and the gas in the wood; and the smaller part came as a current from the roots. As soon as the excess of pressure in the stem had been relieved, the further and nearly uniform flow was kept up by the root pressure. Changes in the degree of cloudiness produced the waviness of the curves C, D, and E in jig. 5. During the 20 minutes that the flow was decreasing 790 drops (66°°) of sap escaped. Of this not more than 40° or less than 25 could have come from the roots. (This will be seen by a study of 1909} MERWIN AND LYON—SAP PRESSURE IN THE BIRCH 457 curve B.) Therefore, 32°° is close to the amount supplied by the roots and therefore about 34°° came from expansion within the tree. The experiment of two days before showed the amount of gas in this tree to be 45 to 80°°, an amount which, by expansion, is sufficient to account for the flow here considered. 20 ‘ 5:25 6:05 6:45 7:25 AM \ it > % ‘ Sects oe ore ; a oe ™S \ : SS 3 x => —— 2 B ——+$_ —__-— ot Re ae A a = 9 min, 10 20 30 40 50 Fic. 5 —A, pressure ay the base of a white birch, April 16, 1906, while flow was taking place from a hole ff up; B, rate of flow in drops per minute of the hole above A; the continuation of curves A and B are D a in another tree the decline of pressure while sap was flowing freely is shown by C EXPERIMENT 3.—To determine the amount of expansion of saturated cell-wall substance of birch wood. Across the grain of a white birch plank thin shavings were taken. From these the air was entirely expelled under the receiver of an air pump. The shavings were then transferred to a 100°° pycnometer. The pycnometer was filled up with freshly boiled, distilled water, and weighed at 6° C., and again at 32° C. The weight of the pycnometer 458 BOTANICAL GAZETTE [DECEMBER full of water alone was also taken at these temperatures. Finally the weight of the completely dried shavings was found. Now the specific gravity of dry cell wall substance is approximately 1.56, and the volume of saturated cell wall substance is nearly 3/2 that of dry cell wall substance. Then let a=increase in weight of pycnometer full of water from 32° C. to 6° C.; 6=increase in weight of pycnometer full of water and shavings from 32° C. to 6° C.; c=increase in volume of pycnometer from 32° C. to 6° C.; d=volume of pycnometer; e=volume of saturated cell wall substance; o.0046=expansion of 1°° of water from 6°C. to 32°C. Then b+c—(d—e) (+) e€X0.0046 = the ratio of expansion of cell wall to the expansion of water from 6° C. to 32°C.7 Now, by substituting the values obtained in the experiment, ; : +0.066 0.4975 +0.066—(r00— 12,6) (2-438 +2:28%) =2.2 12.6X0.0046 =the desired ratio of expansion. PETROGRAPHICAL LABORATORY ARVARD UNIVERSITY }| © These are the figures given a Sacus, Hartic, and others, and used in comp — the tables of the Vermont Bulleti 7 This formula would need a corrections for more exact work, ad “ accurate than the factors of specific gravity and volume of saturated cell wall. is more BRIEPER ARTICLES CONCAVITY OF LEAVES AND ILLUMINATION (WITH ONE FIGURE) Concavity of the upper surfaces of leaves is of extremely common occurrence among the higher plants. WIESNER, in an important paper,’ has discussed this concave upper leaf surface as a characteristic of the peripheral leaves of woody plants, and states that the leaves within the shadow of the crown of trees (with concave outer leaves) are generally flat or nearly so. He classes these and other leaves which are capable of Fic. of cross-sections of leaves, taken at right angles to the midrib (if there is cae cau through its middle point. #. a, Astilbe decandra; b, Prunus persica; c, Syringa vulgaris; d, Akebia quinata; e, Citrus medica; /, Styrax japonica; g, Begonia semperflorens; h, Schizophragma hydrangeoides. some kind of temporary or permanent adjustment to the amount of light received as panphotqmetric leaves, regarding the concavity as useful in preventing injury to chlorophyll by excessive sunlight. OLTMANNS? calls attention to the fact that the leaflets of Robinia Pseudo-Acacia are concave on the south sides of trees, but flat on the north sides. It seemed to the writer worth while to make some notes as to the occur- rence of the concavity in question among various genera, particularly among trees and shrubs, and to take a few measurements of the amount of con- t WIESNER, J., Anpassung des Laubblattes an die Lichtstarke. Biol. Centralbl. I-15. 1899. 2 OLTMANNS, F., Photometrische Bewegungen der Pflanzen. Flora_79:232, 233. 1892. 459] {Botanical Gazette, vol. 48 460 BOTANICAL GAZETTE [DECEMBER cavity in shaded and unshaded leaves of the same individual. Most of the species observed were growing in the Botanic Garden of Harvard University. No attempt was made to pick out particular families for examination, but notes were made on any leaves, especially of dicotyledo- nous trees or shrubs, that showed decided concavity of the upper surface. Some slight amount of deviation from flatness seemed almost universal. The observations were made on mature vigorous leaves during the first week in September. The leaves or leaflets examined in many instances showed a rather definite dihedral angle, as in a and 3, fig. z. More often the surfaces on each side of the midrib were decidedly curved, as in the cases c-f, while some leaves, as in g and h, showed no semblance of an angle in the cross- section, but formed a rather deep trough, with curved sides. Measurements of angles were made by means of two straight-edged pieces of brass, hinged at one end and applied outside the leaf or leaflet at right angles to the midrib. In case the leaf surfaces were somewhat convex beneath, the angle taken was that subtended by a tangent to the middle points of the halves of the leaf. Plants of 31 families of dicotyledons, comprising 52 genera and pos- sibly 200 species, were noted as showing decided concavity of the upper surfaces of the leaves. Little attempt was made to find out how generally marked leaf-concavity characterized the various species of the genera examined. In some instances, e. g., Viburnum, it occurred in almost all the species accessible for observation, while in other cases, e. g-; Magnolia, Acer, it was present in some species and absent in others. « e The following measurements of dihedral leaf angles or concavities were obtained: Species Angle in degrees, | Angle in degrees, shade Akebia quinata (leaflets).............. 106 167-180* Magnolia acuminata.........4........ 80-180 | 180 or recurved Astilbe decandra (leaflets)............. 80-153 180 or recurved (167) Hydrangea quercifolia................. 134-180 180 or less chizophragma hydrangeoides......... 28-1 180 or less Fothergilia Gardeni.. <5 2. 34 80-180 180 or less Robinia Pseudo-Acacia (leaflets)....... 90-137 180* Begonia semperflorens................ 23-50 108-180 Aralia pentaphylla (leaflets)........... often semicircular 180 Ligustrion Thota. occ. iene be 5 180 Syringa vulgaris........... Sar SipaeeeA 55-145 130-180 Cephalanthus occidentalis............. 102-153 180 Viburnine mite. soso 83-105 180 eee OLS * The chade] n Ve Nice ee a eee 1 by the foliage of the plant itself. en ee a wall In the tu. Lod 1 Pipes oe ee | 1 1909] BRIEFER ARTICLES 461 It is undoubtedly a fact that the great majority of woody dicotyledons have leaves which when freely exposed to the sun are concave on the upper surface and that this concavity usually lessens or disappears in the case of much-shaded leaves on the same plant. WIESNER’s conclusion that this conformation is due to the effects of powerful illumination seems on the whole to be plausible. It is not safe, however, to assume, as he does, that we have here an undoubted case of protective adaptation, to ward off the injurious effect upon chlorophyll of excessive insolation. In order to prove this it would be necessary to explain many real or apparent exceptions to the assumption that greater concavity should go with greater illumination. To cite the first instances that occur: Acer Negundo is hardly, if at all, more exposed to excessive sunlight in its usual habitats than is A. sacchari- num, and yet the former has trough-like leaflets, while the leaves of the latter are nearly flat. The Japanese Ligustrum Ibota comes from a region not enough more subject to excessive sunlight than that of the European L. vulgare to account for the great difference in the flatness of the leaves of the two species. Vinca rosea, a West Indian weed, might be expected to have leaves much more concave than those of the European V. minor, but the reverse is actually the case. Occasionally leaves growing in shade may be decidedly more concave than those growing under greater illumina- tion, as I have noted in one case of Kalmia angustifolia. Finally, it is difficult to explain on any theory of utility of concave leaf surfaces in protect- ing chlorophyll the fact that the angular values obtained for leaves of the same individual, grown under similar conditions, vary somuch. The angles given in the preceding table for each species were in many instances obtained from leaves which apparently received almost identical illumination, since they grew fairly near together and were sometimes almost in contact with each other. Yet, as will be observed, the angles for sun leaves some- times varied in a ratio as high as six to one. Equally difficult to explain is the fact that in some genera, e. g., Prunus, Pyrus, Salix, the whole tree may show little difference in the flatness of the leaves, all being angled whether they grow in sun or shade. Instead of trying, as WIESNER has done, to establish the critical intensity of illumination at which leaves of a given species cease to be panphotometric and become euphotometric, it would seem to the writer better worth while to look for some relation (always on the same individual) between illumina- tion and the average amount of angular divergence of the halves of the leaf, basing all statements on a large number of measurements.—JosEPH Y. BercEn, Cambridge, Mass. 462 BOTANICAL GAZETTE [DECEMBER ROEZL AND THE TYPE OF WASHINGTONIA The palms on which WENDLAND founded his genus Washingtonia were grown from seed procured by RoEzL. They purported to have come from “Nord Mexico, bei Arizona, am Rio Colorado,” but where they really came from has never been ascertained. In investigating the history of the genus it proved very difficult to obtain any account of Rorz’s American explora- tions. I was able to learn only of a journey made by him across the north- ern continent in 1872, and was therefore led to assert? that this was his only visit to our country. In fact, however, he had made a far more extended tour in 1868-1870, in the course of which he explored much of the United States and Mexico, and of Columbia in the southern continent. Some account of these journeyings is given in notes published by ORTGIES in volumes 20 and 23 of Gartenflora. Dr. TRELEASE, director of the Missouri Botanical Garden, has obligingly furnished me with an abstract of these notes, and from them I am able to present the following account of ROEzL’s explorations in the United States. OEZL must have gone from Europe directly to Mexico, and he spent the winter of 1868-1869 in collecting in that state and in Yucatan. In March of the latter year he sailed from Havana for New York. He then visited several of the seaboard cities and made some collections in the Alle- gheny mountains, after which he departed for the west by way of St. Louis, Chicago, and Omaha. On July 15, 1869, he was in Cheyenne, and * August 28 in Truckee. Considerable time was devoted to collecting 17 Utah and Nevada, but by November 7 he had reached San Francisco, by way of Sacramento. After a run back to Nevada City he returned to San Francisco, and went thence to San Diego. The object of his southern trip was to gather Delphinium cardinale, and he sent to Europe two thousand roots that he supposed to be of that species. Eventually, on flowering they proved to be one of the blue larkspurs, probably D. Parryi. Here also he got two plants which were introduced to European cultivation as Yucca schidigera and Y. Ortgiesiana, unquestionably the species now known 4s Yucca mohavensis and Hesperoyucca Whip plei. Roezz returned to San Francisco in time to sail on January 18, 1870, for Panama, and after g extensi llections in Columbia and Mexico, again reached San Francisco August 1, 1870. PAs After a week spent in Hoopa Valley, he sailed for the north, visiting 3 Bor. GAZETTE 44:414. 1907. Footnote ro on this page should be — follows: dele 1889: 330; for Jour. Bot. 1874: read 1884:; for Gard. Chron. 2+5 1889 read Gard. Chron. N.S, 24:521. 1888. 1909] BRIEFER ARTICLES 463 Astoria, Portland, and Ft. Vancouver. In September he was among the mountains of the upper Columbia River, but by October he had returned to the Sierra Nevada of California. It does not appear when he finally left California, but by the middle of December 1870 he was again in Panama. ‘The first two months of the new year were devoted to revisiting Columbia, after which RoEzz returned to Europe. It appears from this account that the only opportunity which RoEzi had of procuring seeds of Washingtonia was during his visit to San Diego, in December 1869. The notes, however, contain no reference to this palm. But a visit to any of its desert habitats would certainly have been an experi- ence too notable to have failed of record. Nor is it probable that his visit to San Diego, so short and so diligently occupied in collecting, could have afforded time for the difficult journey to the desert. The vague and con- fused habitat assigned to the palm is itself a sufficient evidence that the collector, from whom the information must have come, could never have visited a native grove. It is safe to conclude that the seed he sent to Europe came from some of the older cultivated trees at San Diego, and that his pardonable ignorance of local geography prevented him from correctly understanding what was told him of the location of the indigenous groves. —S. B. Parisn, San Bernardino, Cal. ~ LONGEVITY OF SEEDS In the Botanica, GazeTTE for January 1909, p. 69, CROCKER, in referring to my paper on this subject, concludes with the remark: “I believe I am doing the author no injustice when I say that it is impossible to tell from his paper in how far it is a contribution and in how far a com- pilation.”” May I say that the utmost care was taken to quote the authority for every record or fact that was not original, and that I am unable to find a single case in which this was not done. If any such omission occurs it is a purely accidental one, and I am prepared to offer both a public and a Private apology to any author whose name is omitted as the authority for a record for which he is responsible. Naturally, however, if on repeating a test or experiment a more or less divergent result is obtained, the original authority can hardly be given for the changed statement of fact, which in many cases directly negatives the original record. The latter, however, Is given in all cases with the author’s name appended, so that it is difficult to see any foundation for CROcKER’S criticism.—ALrreD J. Ewart, Uni- versity of Melbourne. 464 BOTANICAL GAZETTE [DECEMBER REJOINDER In spite of Ewart’s very energetic objection to my criticism of his paper, I maintain that the criticism is entirely justifiable. To escape personal bias I have asked several persons to read passages of EWART’s article and to say who contributed the data. In every case they decided that they were Ewart’s, though this is not the case. As an example, I cite the first part of the paragraph beginning at the foot of p. 197, dealing with Plantago major, P. Rugelii, Thiaspi arvense, and Avena fatua. The data are all given in my article,4 but one would not know from Ewart’s statement that this was their source. Again, in the paragraph beginning near the top of p. 192, EwArT gives the arguments against FISCHER’s conception of the cause of delayed germination in the seeds of water plants as if based on his own work. All these arguments are given in another paper of mine,’ issued five months before Ewart’s. In the same paragraph, he says: “‘Since the above was written, CROCKER (Bot. GazETTE 1907, 374) has shown, etc.’”? One would have expected a writer who is so careful to give credit where it belongs to recast this para- graph after he discovered my article, so as to indicate proper priority. I mention these as two instances out of several that furnished the basis of my criticism. Ewart speaks again of his results contradicting mine in a number of cases. I must therefore point out again that the matters in dispute are minor details and not cardinal principles in- the physiology of delayed germination; and I should be glad to have anyone compare his paper and my criticism to judge in how far there is evidence that his results disprove mine. I have repeated the experiments upon the disputed points, and have had various competent students do so independently. The results in every case agree with my previous conclusions, as my criticism points out. I am sorry that what I considered and still consider a fair criticism has led to undue publicity. I am sure, however, that neither a public nor a private apology is necessary from Ewart, as the case will rest upon ” merits.—WILLIAM Crocker, The University of Chicago. 4 Crocker, W., Role of seed coats in delayed germination. Bor. GAZETTE 42: 282-284. 1906. 5 , Germination of seeds of water plants. Bot. GAZETTE 44 2375-380 Igo7. CURRENT LITERATURE MINOR NOTICES Malayan ferns.—This work" presents in a single volume a synoptical treat- ment of all ferns known to occur in the Malayan Archipelago; its elaboration has been carried on mainly at Buitenzorg, where the facilities for studying dried and living material of this group of plants are exceptionally good. A compendium of the families, tribes, and g introd the body of the work; and the sequence of families, the limitation of genera, and the nomenclature are for the most part in accordance with ENGLER and Prantt’s Natiirlichen Pflanzenfamilien. Fairly concise and clear keys precede the carefully drawn descriptions whenever the genus consists of two or more species, and the bibliography and synonomy are given in some detail; but it is unfortunate that the author has cited so few exsic- catae. The extended spacing and the numerous blank pages make the volume unnecessarily bulky. Moreover, the appendix of some 58 pages, treating princi- pally of ferns discovered affer January 1, 1907, and 11 pages of ‘‘additions, modifications, and corrections” which the author suggests “may be cut out and pasted on the places indicated” will mar materially the practical use of the work. It would seem almost as though publication might better have been delayed until such necessary additions and corrections could have been incorporated in the body of the text. On the whole, however, the work represents careful co'lation, combined with a large amount of original research, and presents in available and reliable form a comprehensive treatment of approximately 1500 species and numerous varieties, representing 10 families and 95 genera. T. he book doubtless w ll find a useful place in the taxonomic literature of ferns.—J. M. GREENMAN. Warming’s Ecology of plants. A correction.—My attention has been called to an unfortunate error in my review of Warminc’s Ecology, viz., the statement that the work was written in English by the author, assisted by Dr. As a matter of fact the work, as it has appeared, is a translation by Professors BALFouR and Groom from manuscript prepared by Professor WARM- inc and Dr. Vant. My mistake was due to the statement on the title-page: ‘prepared for publication in English by Percy Groom,” etc. (which might have been less vague if printed: “translated from manuscript,” etc.), and by a personal knowledge of Warmino’s facility in the English language. It is certainly scant «VAN ALDERWERELT VAN RosENBURGH, C. R. W. K., Malayan ferns. Hand- book to the determination of the ferns of the Malayan Islands (incl. those of the Malay Peninsula, the Philippines, and New Guinea). Royal 8vo, pp. xl+ 899+ 11. Batavia: n kkerij. 1908. 2 Bor. GAZETTE 48: 149-152. 1909. 465 466 BOTANICAL GAZETTE [DECEMBER enough credit to a translator to acknowledge his full share in such a work as this, a share that is most burdensome, and too little appreciated as a rule. Englis and American readers are certainly most grateful to Professors BALFouR and Groom for making accessible not only this new ecological treatise, but the other great ecological masterpiece as well, Scummper’s Plant geography.—H. C. COWLES Pharmakognostischer Atlas.—Kocu> has followed his Mikroskopische Analyse der Drogenpulver with a second part for the use of apothecaries, whole- sale druggists, sanitary officials, students of pharmacy, etc. In the arrangement of the text the author has followed his old scheme of different types, numerals, and indentations for greater facility in locating the various histological structures. and detailed descriptions of the individual tissues. Excellent plates of trans- verse and longitudinal sections serve to make these descriptions remarkably clear. The first Lieferung is devoted to cascarilla, red cinchona, and cinnamon barks. The complete work will certainly be useful in the recognition of crude drugs.—K. G. BARBER. Methods in microscopy.—The second edition of the Praktikum of Mosrus* has about the same scope as the first. Directions are given for making prepara- tions and also for some study of the preparations. Only the simplest methods are given, no attention being paid to the paraffin method or to critical methods of staining; in fact, most of the directions, in American schools, would be given orally or would be written on the blackboard for elementary classes which have no need as yet for any complicated technic. Of the 123 pages, 92 are devoted to spermatophytes, 6 to pteridophytes, 5 to bryophytes, and 20 to thallophytes. —CHARLES J. CHAMBERLAIN, NOTES FOR STUDENTS Genetics.—In the fourth report to the Evolution Committee of the Royal Society, BATESON, SAUNDERS, and PUNNETTS present an account of their further studies with poultry, sweet peas, and stocks. Valuable summaries are gt all the studies that have been made on these subjects, the most interesting a being the further evidence of the occurrence of such ratios as 7:1:1:7 and 15:1+1: 15. It is suggested that the types of gametic coupling evident in cases of this kind might explain the occurrence of certain aberrant forms which are generally ‘looked upon as mutants. The term “spurious allelomorphism” is proposed yen of 3 Kocx, Lupwic, Pharmakognostischer Atlas. I, Die Rinden. I Bd. 1 Lief. pp. 26. pls. 5. Leipzig: Gebriider Borntraeger. 1909. M 3.59. - Mostus, Martin, Botanisch-mikroskopisches Praktikum fiir Anfanget. Seco 4 edition. 8vo. pp. ii+123. Berlin: Gebriider Borntraeger. 1909. M3-20 5 BaTEson, W., SAUNDERS, Miss E. R., AND Punnett, R. C., es gies studies in the physiology of heredity, Reports to the Evolution Committee of Royal Society 4: 1-40. 1908. : 1909] CURRENT LITERATURE 467 for the phenomenon of repulsion between two dominant factors or units, as for example when blueness and the erect standard in peas cannot be combined in the same individual, but are found to repel one another. The further work with stocks has mainly had reference to the phenomenon of doubling. The doubled Stocks are always completely sterile and cannot be used for breeding purposes, so that it is not easy to determine the significance of this phenomenon. It is found that single stocks are of two kinds, one of which breeds true to the single, the other of which always throws a certain proportion of doubles when mated with its own kind, and the conclusion is drawn that this second type of single stock is perhaps a heterozygote in which the single character is dominant to the double. In stocks a difference is also found in the constitution of the pollen grains and ovules on the same plant. The presence and absence hypothesis is definitely accepted, and Miss DurHam® in another paper appended to the report shows that on basis of ‘presence and absence,” the difficulties which Cuénor had found in certain mouse crosses completely disappear. In a discussion of the ‘‘presence and absence” hypothesis the reviewer? has shown that the absence of a character may be dominant over its presence quite as well as the reverse. A simple experiment to illustrate this among the other Salient features of Mendelian inheritance has also been described.® He has also published the results? of his investigation into the elementary species and hybrids of Bursa Bursa-pastoris and B. Heegeri, showing that the leaf characters of four elementary forms which were found in nature behave in the typical Mendelian fashion on crossing with one another. The same relation is found to exist between B. Bursa-pastoris and B. Heegeri that exists among the several elementary components of the former species, thus giving new proof of the derivation of the latter species from the former. However, the Heegeri type of capsule which disappears in the first generation of the hybrids reappears in the second generation in a ratio of about 22:1. The important feature of these results for evolution is the fact that four pure-breeding elementary species of B. Heegeri resulted from the cross, when only one had been found before. Correns'° has studied variegation and yellow-green foliage in Mirabilis, Urtica, and Lunaria, in which he shows that the yellow-green form, which he —_—— ® DurHaAM, FLORENCE H., A preliminary account of the inheritance of coat-color in mice. Reports to the Evolution Committee 4:41~63. 1908. 7 SHULL, G. H., The “ presence and absence”’ hypothesis. Amer. Nat. 43:410-419. Tgog §—-——_ A simple chemical device to illustrate Mendelian inheritance. Plant World 12:145-153. 1909. 9——_, Bursa Bursa-pastoris and Bursa Heegeri: Carnegie Institution of Washington, Publ. 112. pp. 57. igs. 23- pls. 4 10 CorRENS, C., Vererbungsversuche mit blass (gelb) griinen sii Sel ae Sippen bei srabilie Jalapa, Urtica pilulifera, und Lunaria annua. Zeitschr. Abstam. Vererb. 1: 291-329. figs. 2. 1909. sted = hybrids. 468 BOTANICAL GAZETTE [DECEMBER calls chlorina, and the white-margined variety or albo-marginata are Mendelian in their hereditary behavior, both these forms being hypostatic to green and the chlorina hypostatic to albo-marginata. Two variegated varieties of Mirabilis Jalapa, on the other hand, give quite unexpected results. It appears that the offspring is more or less dependent upon the character of the particular branch upon which the seed was produced. Baur‘ has found a similar behavior in the white variegated Pelargonium; thus the offspring of a pure white branch gives nothing but pure white seedlings which are incapable of successful growth, while the offspring of pure green branches produce only pure green seedlings. PAUR goes into the anatomy of the white-margined varieties, and shows that there is a _ complete chlorophylless sheath overlying the chlorophyll-bearing tissues, and extending beyond them at the margin. Baur’s theory for the production of such variegated varieties is that the yellow and chlorophyll-bearing plastids are dis- tributed into the two daughter cells at each cell division, and by chance occasionally only nonchlorophyll-bearing plastids are included in one of the daughter cells. Thereafter this white cell gives rise to a cell progeny containing no chlorophyll and thus forming a white patch or streak which is the product of this one cell. When the division is anticlinal the variegation is in blotches, and when periclinal the white tissue becomes either median or marginal, only one case of the median type having been observed. Baur’s results seem to indicate that the male germ cells, as well as the female, contribute characteristic plastids to individuals pro- duced by their union, but this has not yet been actually observed. ‘ The possibility that different parts of a plant may present different hereditary qualities, as shown by Correns and Baur in these variegated varieties and as very generally recognized in the case of the relatively infrequent vegetative muta- tions known as bud-sports, is considered a matter of considerable importance by De Loacu,?? who seems to have found that in certain cotton hybrids some cap- sules of the heterozygote have the characters of the one or the other parent pract: cally “fixed,” while others give a large degree of splitting. Such suggestions 4S this open up interesting fields for investigation, but theoretically it does not seem likely that different parts of the same individual plant can generally have its own special type of heredity. EMERSON‘3 brings together the work that has been done in the study of Mendelian characters of beans, and finds that all evidence now at hand supports the reviewer’s statement that in certain varieties of beans a unit character for mottling is present, which produces an external manifestation only when in the tt Baur, E., Das Wesen und die Erblichkeitsverhiltnisse der “ Varietates albo- marginatae Hort.” von Pelargonium zonale. Zeitschr. Abstam. Vererb. 1:330-35" Jigs. 20. 1909. 2 Dr Loacu, R. J. H., The Mendelian and DeVriesian laws applied to cotton breeding. Georgia Experiment Station, Bull. 83: 43-63. figs. 7: 1908. : 3 Emerson, R. A., Factors for mottling in beans. Annual Report Ame ee Breeders’ Association 5: 368-376. 1909. 1909] CURRENT LITERATURE ; 469 heterozygous state. EMERSON concludes that there are two distinct and unrelated units for mottling, one of which is a typical Mendelian dominant, the other becoming evident only in the heterozygous state, and on this basis he works out the expectation of various types of crosses. It remains to be demonstrated by actual breeding that such peculiar ratios may exist as 11:5, 21:38, 33:15, 16, etc. A number of more or less popular expositions of Mendelism have appeared, and it is not necessary to mention these except in case new scientific matter has been used by way of illustration. One of the best of these general discussions is that of BAur,"4 in which the illustrative material is almost entirely derived from his own experiments with Antirrhinum majus. In this species 15 or more differ- ent hereditary units have been demonstrated, and the author inclines to the view that much of so-called fluctuating variation is really Mendelian splitting of less prominent unit characters. The number of demonstrated units in this species exceeds the number of chromosomes, which leads the author to the conclusion that whole chromosomes cannot be the units upon which these characters depend. AUR adheres strictly to the presence and absence hypothesis. SPILLMAN,'S in a review of Baur’s paper, shows that so far as yet demonstrated the individual chromosomes may be the fundamental bases of these unit characters, although several instances are known in which the number of demonstrated unit characters in a species is in excess of the known number of chromosomes. The crucial test must be the finding of an individual having more independent characters than sy has chromosomes. This has not yet been done. 6 has once again repeated one of MENDEL’s original experiments in order to determine whether there is any influence of pre-parental ancestry upon the offspring, a question involving the essential difference between the Mendelian and Galtonian conceptions of heredity. It was well that this experiment should be undertaken by one who was in the beginning a staunch Galtonian. The result of the t leads DARBISHIRE to the conclusion that ‘‘there is nothing like ancestral cuatiation within the limits of a single unit character,” or in other words that segregation is perfect and the recessive character appears in as large a proportion of the offspring of a heterozygote after six generations of selec- tion to the dominant character as in the F,. The Mendelian theory of heredity has produced a very deep impress upon the practical work of plant and animal breeding, and a considerable number of papers have appeared from economic sources which present valuable a Olly data in support of this theory, and indicating the extent of its applicability. a few of the more important of these papers can be noted here. Besides the sade ™4Baur, E., Einige Ergebnisse der experimentellen Vererbungslehre. Beih. medizinischen Klinik 4: 265-292. 1908. »sSprttman, W. J., The nature of “unit” characters. Amer. Nat. 43:243-248. T909. 6DarpisHire, A. D., An experimental estimation of the theory of ancestral contributions in heredity. Proc. Roy. Soc. London B 81:61-79- 1999- 470 BOTANICAL GAZETTE [DECEMBER of Dr Loaca already mentioned, which shows that Mendelian behavior occurred n a certain cotton hybrid, BAtts'? has discussed cotton hybrids in a compre- Sainte way, showing that at least 21 characteristics of the cotton plants behave as unit characters. BALLs declares that, while he does not know the exact num- ber of chromosomes in the cotton nucleus, there are certainly not over 20, thus placing cotton with Pisum and Antirrhinum, as species in which the number of known unit characters exceeds the number of chromosomes. Surtont® has carried on extensive crossings in Brassica and found that in a cross between the Swede turnip and the Ragged Jack kale there is a strict Mendelian behavior in which two unit characters are involved, namely, the fleshy character of the root and the curled leaves. The ratio of 9:3:3:1 appeared very clearly in the reciprocal hybrids of the cross. The glabrous-leaved brassicas (B. oleracea and its allies) would not cross with the hispid-leaved species (B. rapa, B. campestris, etc.), and crosses between the turnip and Swede turnip were sterile. Nitsson-ERLE’? maintains that practically all of the supposed mutants if not all which have been found in wheat, oats, and other similar grains split after the Mendelian fashion, and are in reality the results of occasional cross-fertili- zations, i.e., of “vicinism.’”’” The most important result reported by NILSSON- EHLE is the finding of several instances in wheat and oats, in which apparently identical external characters are produced by the presence of two or more inde- pendent units, thus resulting in the F, ratios 15:1, 63:1, and perhaps 255:1 (observed ratio 274:1). In following generations some plants from crosses which showed 15:1 in F, give ratios of 3:1, and others again 15:1. Ina red- grained x white-grained wheat, which presented the ratio of 63:1 in F,, some plants in F; gave again the ratio of 63:1, some 15:1, and some 3: 1, thus confirming the author’s conclusion as to the manner in which the ratios 15:1 and 63:1 arise, and showing them to be typically Mendelian. The ligula of oats was absent in only one variety used in the experiments. This crossed with numerous other varieties sare ratios 3:1, 15:1, 63:1, and in one case apparently 255:1 (actually 274: 1), in different crosses. He concludes that his results prove the correctness of the presence and absence hypothesis, and that not a single fact among his crosses is opposed to the ‘‘purity” of the gametes. He also, like Baur, would explain the inheritance of certain apparently fluctuating characters as due to Mendelian splitting of units having similar functions. 17 Batis, L., Some aa aspects of cotton breeding. Ann. Rep. Amer. Breeders’ Assoc. 5:16-28. 1909 18 Sutton, ARTHUR W., Brassica crosses. Jour. Linn. Soc. Bot. 38:338-349 pls. 12. 1909. 19 Nirsson-Ea ze, H., Einige Ergebnisse von Kreuzungen bei Hafer und Weizen. Botaniska Notiser 257~294. 1908. Kreuzungsuntersuchungen an Hafer und Weizen. pp. 122. 199% Lund: ‘Hakan Ohlssons Buchdruckerei. 1909] CURRENT LITERATURE 471 East’? finds that dent and flint corns differ from one another in a considerable series of correlated characters, and that these combinations of characters are maintained when these types are bred with the sugar corns. Although je flint or starch character of the grains is not then visible, breeding tests show that one or the other of these is latent, so that there is a ‘‘flint” series of sugar corns and a “starch”? series. So far as evidence goes at the present time, the Mendelian method of behavior is most clearly present in crosses between the most nearly related forms, and shows the most decided tendency to break down in the crosses between more distantly related things. For this reason all studies of the behavior of species- hybrids become of the greatest importance. Hurst?* has made a survey of orchid hybrids with special reference to the inheritance of albinism, and finds the phenomena so similar to those already worked out in sweet peas and stocks that he is convinced that they present typical Mendelian segregation. Lock’? gives a report on some spccies crosses of the genus Nicotiana. This is only a prelimi- nary report and many points remain to be cleared up. He finds that the second generation of some of these crosses shows a wide range of distinct types, which he believes can be analyzed on the same basis as the sweet peas and stocks have been. Color of pollen and of corolla, and form of corolla tube (bulged or funnelform) showed typical segregation. In many characters pertaining to general habit, leaf form, etc., segregation was not present or only doubtfully. Lock suggests the possibility that “‘true-breeding” hybrids may result from the failure of any but homozygous combinations, this idea being made possible by the fact that very often the fertility of such hybrids is very low, so that but a small percentage of successful seeds is produced. This matter of non-splitting hybrids between species has also been presented by BuRBANK,?3 who points out that this presents a method of production of new species, probably more important than usually supposed. Although several of the instances mentioned by BuRBANK have not been sufficiently tested, there can be little doubt that the species-hybrids in Rubus present cases of this kind. Upon these exceptional situations the chiet attention of experimenters shou!d be concentrated. Another hopeful direction for research that is being taken up in several quarters is that of making analyses to determine the exact nature of the unit characters. Only in this way can we hope to discover the nature of the character-producing = ia E. M., A note on the inheritance in sweet corn. Science N.S. 29: 465-467. 21 Hurst, C. C., Inheritance of ess in orchids. Gardeners’ Chronicle. Feb. 6, 1909. 22 Lock, R. H., A preliminary survey the Mendelian standpdint Ann. Roy. Bot. Gard. Peradeniya 4: 195-227. pls. 12. 1909. *- the genus Nicotiana from 23 BURBANK, L., Another mode of species-forming. Ann. Rep. Amer. Breeders’ Assoc. § : 4-41. 1909; also, Pop. Sci. Monthly 264-266. Sept. 1909. 472 BOTANICAL GAZETTE [DECEMBER genes. There is a growing sentiment that all hereditary phenomena must rest in last analyses upon a chemical basis. DARBISHIRE?+ has made a careful exam- ination of the starch grains of round and wrinkled peas in pure-bred strains and in several generations of their hybrids. He finds that there are several uncor- related features of these starch grains which result in the hybrids having some of the characteristics of the starch grains of both the parents, thus tending to obscure the fact that the segregation of the starch characters is perfect. Miss WHELDALE?S has studied the floral pigments of a large number of species, devoting her attention most intently to the anthocyan series, but also including a discussion of xanthein, xanthin, and carotin. A useful summary is given of the studies of others upon the chemical composition of these com- pounds, and a large number of observations from her own analyses are presented, the general result being to show that there is a very large number of different pigments having a common fundamental structure, which pass under each of these several names. From these analyses and from experience in cross-breeding: she concludes that at least two features are necessary to the production of the anthocyan color: the one a colorless aromatic chromogen of the flavone series, the other an oxidizing agent which she believes to be a ferment. The details of Miss WHELDALE’s methods of analysis and the lengthy list of literature will prove of great value to students who desire to go into these more intimate problems of genetics. : A similar work from the animal side has been attempted by RipDLE,”° with respect to the melanin compounds, though the author presents no work of his own, simply bringing together in an instructive way the more recent results of investigations in this field. One unfortunate feature of Rippie’s work is his unfamiliarity with the Mendelian work from the experimental point of view. He thinks that he has proved the utter fallacy of the entire body of Mendelian teaching, and that he has demonstrated the continuity of the so-called unit characters, @ statement which contravenes the experience of all investigators who have studied the behavior of pigment characters in actual breeding. No epigenetic hypothesis as yet gives the slightest hope of enabling such predictions as are successfully made continually by workers with the unit character conception.—GEORGE H. SHULL Perception of light.—HAseRLANpT?7 attempts to strengthen his theory of light perception by plants, especially on the physiological side, acknowledging HIRE, A. D., On the result of crossing round with wrinkled peas, with especial reference to their starch grains. Proc. Roy. Soc. London B 80:122-135- 1908. 25 WHELDALE, Miss M., The colors and pigments of flowers, with special reference to genetics. Proc. Roy. Soc. London B 81:44-60. 1909. ———, On the nature of anthocyanin. Proc. Cambridge Phil. Soc. 15+ 137-18 1g0Q. 26 RIDDLE, O., Our knowledge of melanin color formation and its bearing on the Mendelian description of heredity. Biol, Bull. 16: 316-351. 1909. s: 27 HABERLANDT, G., Zur Physiologie der Lichtsinnesorgane der Laubblatter. Jahrb. Wiss. Bot. 46:377-417. 1909. . 1909] CURRENT LITERATURE 473 that the experimental work there leaves much to be desired, while the anatomical relations have been pretty fully cleared up. He discusses, therefore, the investi- gations that have attempted to eliminate the lens action of the papillose epidermis by making plane the surface with water, oil, gelatin, etc.; after which he addresses himself to the question of the residual lens action of the epidermal cells. He shows that in all cases with oblique illumination there remains an unequal excen- tric distribution of the brightness on the inner walls of the epidermal cells, though of less intensity than with dry epidermis. Inquiring into the sensitiveness of the cells in distinguishing differences of illumination, it appears that the more sensitive leaves have about the same capacity, 1/30, as the human eye under ordinary circumstances, the extremes being 1/75 and 1/12.5. But the differences of illumination in the case of papillose epidermis, even when wetted, is far above these figures, and, as HABERLANDT proceeds to show, is often greater even in leaves that have the epidermal cells plane outside and concave on the inner end. In the latter case the differences were from 1/15 to 10/1, according to the obliquity of the light. After discussing the previous more or less contradictory results of the wetting method, in which some of the experimental leaves were not in condition to per- ceive the direction of the light and to respond to it, he describes his new method. This consists of wetting only a part of a leaf of Tropaeolum with water made plane with a thin sheet of mica, and leaving the rest dry. A zone between the wet and dry portions is darkened with a paper screen, and the petiole is also properly protected. Then the two regions are illuminated obliquely from con- trary directions. By varying the relative areas of the wet and dry regions, and the intensity of the illumination, it is easy to determine the relative efficiency of the epidermis under the two conditions. When the areas are equal and the wet area receives double the intensity of light, its direction on the dry side con- trols the response. When the intensities are equal and the wet area is 2.2-4.8 times the dry, the latter still dominates the reaction. We translate the latest statement of HABERLAND?’s theory: “The perception of the direction of light results, according to my theory, from the differences in brightness or the different distribution of intensity upon the inner walls of the epidermis, which may be brought about in various ways. The smaller differ- ences of brightnesss may be produced by the mere convexity of the inner walls of the epidermis. These eased iment as a = (miissen die Reizschwella erreichen) if the outer wall tion of the light is thus excluded; and they may suffice even if the normal collection of light by convex outer walls is made impossible by wetting. Then even the wet leaf perceives the direction of the light and returns, although slowly and generally incompletely, to the usual light position. In these cases the epidermal cells act as optical stimulators, and and though they may be dispensed with to a certain extent, the promptness and precision of the movement are enhanced by their effect in increasing the intensity of the stimulus. This action is especially valuable in the last phases of the adjust- ment, when by the diminution of the angle of incidence, the differences of bright- 474 BOTANICAL GAZETTE [DECEMBER ness on the inner walls, so far as these differences are due to the convexity of the inner walls, may become less and less until they fall below the liminal value as a stimulus.’”—C. R. B. Symbiosis in orchids.—A recent paper by BERNARD?’ recalls his previous studies on the germination of certain orchid seeds and on the relation of fungi to the tuberization of orchids and potatoes. The present paper advances our knowledge of these fungi and places considerable emphasis upon their place in the development of the orchid group. Three species (Rhizoctonia repens, R. lanu- ginosa, and R. mucoroides) have been recognized, described, isolated, and grown in pure cultures for considerable periods. though no spore-bearing structures have been observed, they probably belong to the lower basidiomycetes. The first-named species seems to be the most primitive and most widespread in its symbiosis. Two series of orchids were studied, those of epiphytic and those of terrestrial habit. The growth of th dling plished experimentally in test tubes upon suitable media, and the effect of the fungi and of various concentrations of the media upon their development carefully studied. The results are most interesting and suggestive, and may be summarized as follows: (1) Orchids exhibit a progressive development of symbiosis corresponding to and probably in some measure the cause of their development in phylogenetic series. (2) The evolution in epiphytic and terrestrial families is parallel, and symbiosis is the only common factor which can account for this parallelism. (3) The evolution in symbiosis manifests itself in an advance from independent germination of see with normally developed seedlings, to a germination entirely dependent upon the infection of the embryo by fungi and the development of seedlings characterized by protocorms. In the adult plants various progressive stages of symbiosis are exhibited, from an intermittent infection with sympodial habit to permanent symbiosis associated with the monopodial habit of the host. (4) The fungi vary in virulence according to their species, their host, and the length of time ‘they have lived outside those hosts. Very virulent cultures act upon more highly developed orchids in a similar manner to more attenuated cultures upon more primitive species. (5) Concentrated solutions of the culture media have an effect upon germination similar to that produced by infection by fungi, and both symbiosis and growth in concentrated media result in increasing the concentra- tion of the cell contents, which seems to be the necessary condition for the develop- ment of these specialized plants.—Gro, D. FULLER. Recent contributions from the Gray Herbarium.?°—A. EasTwooD pat? Am. Acad. 44:563-591. 1909) has published a ‘Synopsis of the Mexican an 28 BERNARD, Noét, L’évolution dans la symbiose. Les orchidées et leurs cham- pignous commensaux. Ann. Sci. Nat. Bot. IX. g9:1~196. 1909. ; 20 Contributions from the Gray Herbarium of Harvard University, New Series, No. XXXVI (Proc. Am. Acad. 44:563-637. 1909); and No. XXXVII (Proc. Bost. Soc. Nat. Hist. 34: 163-312. pls. 23-30. 1909). 1909] CURRENT LITERATURE 475 Central American species of Castilleja” in which 54 species are recognized, 17 being new to science. A clear and concise key precedes the enumeration and description of species; the same author (ibid. 603-608) describes 12 new species of Mexican flowering plants belonging to different genera—B. L. RoBiNson (bid. 592-596) in a “Revision of the genus Rumfordia”’ records six known species, of which two are here described for the first time, and (ibid. 613-626) under the title “Diagnoses and transfers of tropical American phanerogams” publishes 20 new species and three new varieties, and makes several new combi- nations.—H. H. Bartiett (ibid. 597-602) gives a ‘‘Synopsis of the American species of Litsea,’’ recognizing 11 species, 5 of which are new, and (ibid. 609-612) under ‘‘Notes on Mexican and Central American alders” describes one new species and three new varieties; the same author (ibid., 627-637) has published 14 new species and varieties of flowering plants chiefly from Mexico, and pro- poses one new genus (Basistelma) of the Asclepiadaceae. J. R. Jonnston has recently issued, as Contribution no. 37 of the above series, a “Flora of the islands of Margarita and Coche, Venezuela,” based chiefly on his own observations and collections made on the islands during two expeditions, one in 1901, the otherin 1903. A brief historical sketch of the botany of the islands, an account of the physical features, a catalogue of the species, a list of the economic and medicinal plants, the distribution of species, the composition and relationship of the flora are the main topics presented, to which is added a bibliography of all works that relate directly to the vegetation of the islands. Approximately 650 species are known from Margarita and Coche at the present time; and the author estimates that this number represents about three-fourths of the entire flora. Forty-two species and two new genera have been discovered on Margarita during the course of Mr. JoHNsTon’s preparation of the present publication. The relation- ship of the flora, as would be expected, is with the mainland. The work forms an excellent basis for future investigations on the flora of the islands; it is, more- over, of particular scientific value since the plants on which the catalogue of species is based are deposited in several of the larger herbaria of Europe and America.— . GREENMAN. Anatomy of Zamia.—Martre*° has recently published an addition to the number of investigations in the interesting field of cycad anatomy. Zamia is the subject of the present work, the species studied being Zamia floridana and Z. integrifolia. The paper shows the anatomy of Zamia to be of the ordinary cycad In the embryo, the vascular plate of the cotyledonary node is a protostele. Each cotyledon receives three strands, which undergo the usual branching and anastomosing, and exhibit transfusion tissue at the tips. At the base of the cotyledons the strands are mesarch and may be even concentric; they are exarch in the middle and upper regions. The first leaves are opposite, but later ones 3° Marre, H., Sur la structure de l’embryon et des germinations du genre Zamia L. Bull. Soc. Sci. et Med. de ’ Quest 18:nos. 2 and 3. 1909. 476 BOTANICAL GAZETTE [DECEMBER have the spiral arrangement. The leaf traces arise in the cortex, between the cotyledonary bundles, and there are three for each leaf. Girdling is acquired early. There is no clearly differentiated root structure in the embryo. The manner of germinating is the same as that described for other cycads. The tardily appearing root is tuberized by the activity of a zone of cambium which appears immediately within the endodermis, and proliferates to such an extent that the components of the root cylinder are displaced and the cortex is exfoliated. The root cylinder may be diarch, triarch, or tetrarch, and reduces toward the tip. In its lower part all the tissues are well differentiated, even the endodermis and pericycle. The stems of young seedlings have no secondary wood, the cylinder being composed entirely of endarch leaf traces, which become mesarch farther out in the leaf. The pith of this siphonostelic stem sometimes contains a few isolated vessels. Contrary to the usual custom of looking upon these vessels as remnants of the embryonal protostele, the author prefers to regard them as vestiges of ancestral structure. Marre corroborates the discoveries made by Lanp and the reviewer that the cotyledonary node of Zamia is of the usual cycad type, that there is a tendency to lobing at the tips of some of the cotyledons, and that there is an irregularly arranged cortical cambium, though he describes the last as vaguely cambiform, and does not attribute to it any phylogenetic significance. The microphotographs are a retrogression from the clear and beautiful draw- ings of the earlier papers—HeLEn A. DorETY. Temporary anaerobiosis.—NaBoxIcu has published from time to time in the past ten years short papers upon the behavior of plants under anaerobic conditions; now he gives us a monograph on the temporary anaerobiosis of higher plants.>* There is an elaborate consideration (45 pp.) of the previous work, practically all of which is decidedly adverse to his views. Then follows the experimental part, showing how anaerobic growth is recognizable and presenting the results of an analysis of its physiological characteristics, its periodicity, dependence on temper ature, réle of sugar and alcohol, energetics, and cell division. NABOKICH reports two categories of physiological facts which are not clearly consonant. On the one hand, anaerobic growth seems to be identical with aerobic as to the grand period, geotropic response, and cell division (including karyokinesis). On the other hand, there are peculiarities of anaerobic growth, such as the course of its curve at different periods (though: this can be paralleled in aerobic growth under proper conditions), its specific dependence upon tempera ture and sugar solutions, and the invariable death of the cells. Though NABo- kiIcH holds that his experiments have fully established his fundamental assump- tion of the capacity of higher plants for anaerobic growth, he confesses that he has not succeeded in obtaining an amount of growth beyond the limits of possible for- 3 Nasoxicu, A. J., Temporare Anaerobiose héherer Pflanzen. Landw. Jahrb. 38:51-194. pls. I, 2. figs. 2. 1909. 1909] CURRENT LITERATURE 477 tuitous alteration in length by turgor changes; but he thinks this explanation precluded by the different behavior of the plants with sugar solutions under aerobic and anaerobic conditions respectively. Because of the great increase in growth late in the culture period, he also rejects the possibility of anaerobic growth being due to residual oxygen, even though there must be some not removable by his methods. Taking everything into consideration, NABOKICH believes that aer- obic and anaerobic growth have no necessary connection, being called forth by different factors A reading eS this paper leaves one unconvinced that the author has estab- lished his point, in spite of the apparently prodigious labor the prolonged and very difficult research has involved, with results of minimal consequence. It seems another case of the mountains in Jabor.—C. R. Hybridization.—GicL10-Tos? publishes an attempt to reach theoretical] explanation of the varied phenomena of hybridization. His views are based on his theory of ‘‘biomolecular addition” which may be briefly stated. He supposes that a fertilized egg, A, consists of a series of molecules a, 6, c,d, ¢, . . . n that after a series of chemical transformations owing to assimilation hers arrive finally at a chemical constitution m,n, 0, p, q, . after which each divides into 2a, 2b, 2c, 2d, 2e,...., sak ice to ile ceusnad condition. When this occurs, “‘regeneration of the germ” would be complete. In sexual repro- duction if 4 nd Bg represent the biomolecules of he two germ cells, the Organism developed from the fertilized egg, AB, might have the capacity of regenerating the whole “biomolecule” which formed it, in which case we would have parthenogenesis; or if complete regeneration is not possible we will have sexual reproduction, each of the germ cells regenerating a part. The case in plants, in which both sexes are usually present in the same individual, is not spe- cifically considered. rom this point of view the writer interprets sexuality, synapsis and reduction, fertilization and hybridization. It is further supposed that the zygote AB, while retaining an equal number of male and female biomolecules, yet in the ontogeny undergoes certain modifications, so that the resulting germ cells will be ¢M and N?2; and that the constitution of these is such that they can be added to each other (“biomolecular addition”) to produce again ¢AB9. On this basis the results of crossing are considered from an a-priori point of view and a number of “laws” are enunciated. Explanations of Mendelian Segregation, blending, and other phenomena of hybridization are offered, and predictions made as to the results of cross-breeding reciprocal hybrids. The formal character of the hypothesis makes it probable that it will fail to conform to many of the facts of hybridism, but its viewpoint is very suggestive. For the details of its application see the original paper.—R. R. GATEs. 32? GiGLIo-T 08 ERMANNO, L’eredit& e le leggi razionali dell’ ibridismo. Biologica 2:no. Io. pp. 3 478 BOTANICAL GAZETTE [DECEMBER Graft hybrids.—WINKLER33 has published a further account of his experi- ments with graft hybrids of Solanum nigrum and S. lycopersicum. In all, thirteen graft hybrids have appeared, belonging to five different types, which are named S. tubingense, S. Darwinianum, S. Gaertnerianum, S. proteus, and S. Koelreuteri- anum. Of these forms the first three resemble most S. nigrum, and the last two resemble the tomato, S. proteus being very variable in leaf shape and having leaves similar to S. Darwinianum. S. Gaertnerianum, like many sexual hybrids, often has sterile anthers. S. Darwinianum and S. Koelreuterianum are very unlike in their vegetative organs, but similar in their flower characters. S. pro- teus produces reversions to the tomato, which it most resembles, while S. tubin- gense reverts to the nightshade, it nearest pare Some viable seeds are produced by the =r hybrids, but the percentage of germination is very sma n S. tubingense the length of time required for ripening the fruit is short, ike that of the nightshade, while the maturing time for the seeds is intermediate, and hence the ripened fruit contains immature seeds. The chimeras described in WINKLER’s previous papers also recur, and some others are of peculiar character; e. g., one chimera was S. lycopersicum on one side and S. tubingense on the other, and another was composed of the two graft hybrid forms, S. tubingense and S. proteus. In S. nigro-tubingense one flower had two white petals and three yellow. S. Darwinianum similarly originated from a chimera which was partly S. nigrum and partly S. Darwinianum, and a pure shoot of the latter was obtained only after four decapitations of this branch. S. Gaertnerianum appeared five times on different grafts, in some cases as an independent shoot and in others from a chimera. The forms are all held to be true graft hybrids and not mutations, because they are intermediate between the parents. W1vKLER thinks that graft hybrids differ from sexual hybrids in their marked late but it is too early to say what the cause of this may be.—R. R. Gat Heredity in the pea.—T wo papers by DarpisHtrE% deal with he edity in the a. The first is a very interesting analysis of the types of starch grain in round and wrinkled hybrid peas. It is to be hoped that this valuable paper will lead to many other studies of a similar sort, because very little attention has been paid to the ontogenetic development of Mendelian characters. GREGORY** had previously shown that round and wrinkled peas possess different types of starch 33 WINKLER, Hans, Weitere Mitteilungen iiber Pfropfbastarde. Zeitschr. Bot. 12315345. pl. I. figs. 4. 1 ARBISHIRE, A. D., on the result of crossing round with wrinkled peas, with especial reference to their starch grains. Proc. Roy. Soc. London B 80:122-135- jigs. 6. tables 2 1908. experimental estimation of the theory of ancestral contributions in havedikys Pre Roy. Soc. London B 81:61-79. tables 8. 1909. 35 GREGORY, R. P., The seed characters of Pisum sativum. New tees 2:226- 228. 1903. 1909] CURRENT LITERATURE 479 grains. In the round pea are large potato-shaped grains (p grains), while the wrinkled pea has compound grains (c grains), averaging six parts to a grain. In addition, both types possess a few very small circular grains and in the wrinkl d pea are found occasional f grains, though these are very rare. In the hybrid F, the starch grains are perfectly intermediate between those of the parents, although the character roundness is dominant. The majority of the grains in F, are large and round; some, however, are compound, averaging three parts to a grain. Heterozygotes (DR) in the F, were of a similar sort, but extracted wrinkled peas in F,; showed an occasional p grain. DARBISHIRE concludes that round differ from wrinkled peas in four pairs of characters: (1) the shape of the pea, (2) its absorptive capacity for water, (3) the shape of the starch grain, and (4) the con- stitution of the starch grain, i. e., whether single or compound. In a more recent paper the anihoe tests the theory of ancestral contributions as applied to Mendelian heredity. Yellow and green peas obtained from India, Canada, China, Russia, and other sources gave similar results. The recessive character appearing in F, was shown to behave as though it was as pure as that borne by a pure race. It was concluded that “there is nothing like ancestral contributions within the limits of a single unit character,” and that in such cases in predicting the results of a cross, ‘‘the somatic characters not only of the parents and of the ancestors of the individuals mated, but of the individuals themselves, may be left out of account,” aioe being based on the theory of the contents of the germ cells.—R. R. GATE Diversity in cotton.—Several bulletins by Cook and his associates in the Department of Agriculture*® are not only of great commercial value in directing the activities of cotton growers, but are also of considerable interest as studies in variability and its causes, and the results of crossing. Without attempting to mention all the topics considered, one or two of them may be referred to as of special interest. The diversity found in Egyptian cotton introduced into Ari- zona is = to be ts — kinds: (1) diversity due to hybridization, (2) diversity due t mplet tization, (3) diversity due directly to differences in the physical esvirenae and (4) diversity i in different parts of the same plant. Slight differences in the external conditions have large effects in the productivity of individuals by determining the production of sterile or fertile branches. 36 Cook, O. F. Page agn es of a primitive character in cotton hybrids. Bureau Pl. Ind., Circ. 18. pp. 11. 190 he s cla is line breeding over narrow breeding. Bureau PI. Ind., Bull. ae Pp. 45. 1909 pressed and fauinstheed characters in cotton hybrids. Bureau PI. , Sup Ind., Bull. 147. pp. 27. 1909. Coo K, O. F., McLacaian, A., AND Meape, R. M., A study of diversity in ei cotton. Bureau PI. Ind., Bong 156. pp. 60.. pls. 6. 1909. Coox. O. F., Local adjustment of cotton varieties. Burean PL. Ind., Bull. 159. PP-75- 1909. 480 BOTANICAL GAZETTE ._ [DECEMBER It is found that when a race of cotton is introduced into a new locality it usually shows at once an epidemic of variation in tats directions, many of the plants showing a large amount of deterioration. The tendency can be eradicated only by selecting from the best (unmodified) ee in the new locality. In this manner a reasonab y constant race is finally obtained in the new locality, the process being known as local adjustment. New-place diversity is thus a phenomenon distinct from ordinary fluctuating variability, and of prime impor- tance in connection with acclimatization. These new-place variations are not adaptations to the conditions, but are considered to be ‘‘experiments in accommo- dation” or as “‘affording the materials from which the more definitely accommoda- tive characters may be developed.”’ Neither are they directly impressed upon the plants by the external conditions, but much of the diversity is believed to represent “transmitted characters which have been able to come back into expression because the change of conditions has disturbed the previous adjustments that selection had established.”—R. R. Plants with HCN.—MrranpeE finds’? that green plants which contain cyanic compounds, if subjected to the action of chloroform, ether, and other vapors that check photosynthesis, exhale a strong odor of hydrocyanic acid. He proposes therefore to use GUIGNARD’s test3® in connection with this process to determine what plants contain such compounds. The test requires only a short time and avoids all the complicated and troublesome processes necessary for chemical analysis. Besides it seems to be more delicate and certain. Thus MIRANDE seit that the presence of hydrocyanic acid may readily be detected in Arum maculatum, a plant in which the existence of HCN, long in controversy, has lately been ae by analysis.—C. R. B. Geotropism and metabolism.—The only experiments which have claimed to show a direct connection between irritability and metabolism have been those of CzaprexK and BErTEL, who found that in geotropically stimulated roots there was an accumulation of reducing substance, which they identified as homogenistic acid. The precise character of this substance has been controverted. Now come s Grare and LinsBAvER,?? who report that in the material used by them (Lupinus albus and Vicia Faba) the absolute amount of reducing substances (character not determined) is very small and far below the values found by CZAPEK. More- over, there was no constant difference between the stimulated and the unstimulated roots.—C. R. B. MrRanDE, M., Influence exercée par certaines vapeurs sur la cyanogénése végé- tale. ead rapide pour la recherche des plantes A acide cyanhydrique. Compt. Rend. Acad. Sci. Paris 149:140-142. Ig09. _ 38 Bot. GAZETTE 43:288. 1907. x0 Grare, V., AND Linsnaver, K., Zur Kenntnis der Stoffwechselnderungen bei geotropischer Reizung. Sitzb. K. Akad, Wiss. Wien Math.-nat. Kl. 118:907-916. 1909. GENERAL INDEX Classifie] entries will be found under Contributors and Reviews. New names and names of new genera, species, and varieties are printed in bold face type; syno- nyms in zalic. \canthocereus, Britton and Rose on 310 L £ f Adaptation in a nea Scott on 315 Adelmeria, Elmer on 396 Revinctia ‘Kusano 0 n development of 75 African plan rage ae on 157, 395; Gilg paris 1574 Girke on 157; Krause on 158; ax Arostyras, "Perkins os ee on 158 gave, Drummond o Aaacponi, extology 0 of a6 Albinism, Baur on fohenrence of 72 Alchemilla, Steiner on mildew of 235 Algae, fungus p f rmnaria, Rigo in 33 fie icae 14 anita, markable “epane nce of grav ity on direction os growt 414 bo yg) oe nets Acacia 5th Asner ‘Naboki ch on temporary 476 y, Gleichenia, Boodle and Hiley gymnosperms 84, “Hill and Rae on Sia ovule yrica, Ker- shaw on 3 - Banotace Smith on 77 Anisophyll ss a Anthers, —— of, Schneider on 317; Steinbrinck 0 Anthocyan. Anulocaulis Sta son diepensak of “ate by 319 Apparatus for plant ered 30 Appun aL gre emalen Arbaumont, J. de, w Ears 239 Aecoceral Chry santa variation of 4, 7 Ascomycetes, perithecium of, Engler and 7 Peedegcorktn Dale on sexuality 398 Aspergillus, Dale on sexuality 39 plenium, M eo. F. 283, 321 Auxograph, demonstration 302 Awano, S., work of 79 481 B Baccaureopsis, Engler on 396. Bachman, Freda M., work of 80 Bacillariaceae, Miiller on 396 Bacillus subtilis, ammonification by 106 Bacteria, Meyer on nucleus of 77 Bailey, Irving poe ‘Eeology” (see Warming) Bal - 470° i K Barker, P. T. fs yond: 159 Barnes, C. R. 64, 66, 67, 73) 74s 751 79; 78, 79, 80, 154, 155, 157s 160, 2375 — 239, 240, 306, 308, 313, 317, 318, 319, 320, 39%, 399; 400; 472, 4 475, 4 Bartlett, H. H., work of 4 Bateson’s «Mendel’s viicapies of hered- ity” 61 Baur, Edwin, work of 72, 4 ork 468 Beccari, O., work of 157; - ** Asiatic Bergen eph Y. 275, 459 Bergeocacts Britton and Rose on Be what work of 75 rnard, Nol, work of 474 _ W., ork of 232 232 Breeding corn, Morrow and Gardner on 396 iene Ass’n, rae Rept. 392 Briquet, J., — 3 Panon: N. L., work of 310 Brown, W. Bruchmann, i, “work of 76 Buchanan, R. bas 231 Burbank, L., work of 471 Butters, F. K., work of 240 € Cabomba, embryology of 57 reve ies ae! on 395 Calesta V., Ca gitice. Robinso on and Fer nald on 158 peat compared with Hel acaie: Calopogon, embryo sac 129; gameto- phytes a megaspores 126; micro- pores Campbe iL, ds ie oe of 316, 317 Caragana, Komarov on 234 —— monoxid, ‘Kraschénnikoff on of 240 oreopola ae rustica ae Standley on 158, 234; viscidula Caalophyilum, Butters on seed of 240 Central Amer vee? — on non Hes 475; Maxon of 3 on Se of pe Seallseribed aa fro Centrosomes, in Marchantia, Schaffner on 80; ypoca’ atin Neha on 73 Cephalocerews Giirke on 396 as s, Purpus on 1 38, 233; Weingart 15 Colne. Murrill on 396 ye ei ache —— on 395 Chamaeanthus 233 Chamberlain c. ie eg 74, 76, 77, 80, 234, 466 Cheninacts of Lycopodium sperms, Bruchmann on Chemotropism of fungi, Schmidt on 78 Chloranthaceae, Robinson on 234 Chlorophyceae, Gardner on 232 Chlorophyll bodies, d’Arbaumont on 239 Chlorophyll, in evergreens, Stein on 320; oe eeds, Monteverde and Lubimenko n 74 Christ, H., “‘Flore de la Suisse” 154; work of 23 Christensen, C., work of 157 avior in Oenothera 48 Q & ‘ou. Og 5 FeeE Es ° B Q 5 § 5 Soe Merrill on 395 Clem ao ork of 396 Bohs of 1 ia ux, A., Calletoivickaite, pale ett in, Carica r2, Lindemuthianum 15 ins, INDEX TO VOLUME XLVII! [DECEMBER Commicarpus, Standley on Coniothyrium Fuckelii, variation of 11, 19 Connaraceae, Merrill o Conn’s ‘Agricultural bacteriology,” a3 Contributor s: Atkinson, G 5 4 : 81, 239, 308, 311, 312, bey ee 317) 318, 319, 320, 30 4 Cowles, H. C. e€ Greenman, J. M 155, 156, st, a b 395; 465,474 4743 Cries. s, Robert He Man Me Land, W I G4 ; Lipman, ‘ 06; Lyon, H. 442; McAllister aes ? F. 200; Merwin, H. C. 442; Osterhout, W. J. V. 98; Ottley, Alice M. 31; Over- ;_ Pace, Lula 126; ce, nou chi, Shigéo aS; 236, 231; 380 Convolvu ‘lac cae 233 Conzattia, yee n 310 Cook, Mel. T. 56; work of 479 ooper, ww. S. 154 Copeland, E. B., work of 157, 234, 395 Corn breeding, Morrow and Gardner on 6 Costaricia, Christ on = Cc Rica, plants of 2 Cotton, Cook on diverse in 479 Coulter, J. M. 81, 239, 308, 311, 31% 34, 315) pre 317, 318, 319, 329 393+ Co ati iL oe 149,152 30% 4 65 Crassulaceae, Britton and Rose on 310 Creonectria, euwer: ‘oh 395 Crocker, Wm. 463 ruciferae, Calestani nm 232 Cryptocarya, gimemeiites on 395 1909] Culture solutions, Benecke on 78 nd on 395 Cyperaceae, Palla on 23 gy, of Aglaozonia 380; of ae "380; of Florideae, Kurssanow on 2 D Dangeard, P. A., work of 159 work of - 472, 478 f nzlin on Dode, ork o Delchedacbee Ule on 233 Dorety, Helen A. 475 Dérfler’s ‘‘Botaniker Adressbuch” 66 Drosera, Meera g Ss on a hybrid 234 Drummond, J. R., work of 396 Dryopte Gicisionsen on 157 Durand, "Filia s J. 66, 77 Durham, F. H., work of 467 E East, E. M., work of 307 471 474 nt a Seciinadag minutiflora, Britton and Rose Ec er Sophia 224 Betrogella apr arge 338 hlam, F., 157, 233 Facog se S, "DeCandolle on Philippine 395 Plcosacidre n japonicum ean ig abe ecd influence of on microorgan- S 359; and seiphettan Bae Kolton- Imer, A. D ee = of 157, 396 Elmeria, Elmer 0 157 Embryo, of Bra sini 57; of Cabomba 57; of Cas stalia oe 96; of Juniperus of Nymphaea eae 365 ‘ tonia ae 2 i mbryo sa alopogon 129; double fertilisation, Porsch 0 nS pyr of Widdring- INDEX TO VOLUME XLVII! 483 geny of 76; of Habenaria 242; of Pandanus, Campbell on 316; _ of Smilacina 200; of Symplocarpus, familien” 67; work of 7, 157, 395 Englerodoxa, H6 wi 232 Endosperm of H are 248 Entophivets bulligera 33 Environment, Maasegre & ae due to 1 Sp taboos variation in 4 Merrill on 1 oe work of 73 s, Clements and Shantz on 396 158 ax oO uxena, Calestani on hel eg Stein on n chloroph in 320 Evolution, tenden mong gymno- A. J. 463 pele Lutz on fungus 78 Exogone, Hennings on 234 Fawcett, W., — . 232 396 ernald, ole Copeland on 157, 234; Mexican 310; oe on Bolivian 158, on Ecua- = a, Fennentaton and respiration, Kosty- tschew on 399 Fertilization, _ — 383; in Juni- Tus 31; rsch on phylogeny of 76 ars of Darwinism” 392 pe ouble «pity ye phyllie” 306 " Figdor’s “ Aniso Fin Flora of ‘Krakatau, Campbell on 317 Florideae, Kurssanow on cytology of 236 Fossil plants, Scott on adaptation of 315; Sin on araucarian 4 Fraine, “E. se work of 314 Frost, ake due to environment I; ¢ on 78; North American, Peck on 396 G ametogenesis in Cutleria 3 ome eng of Pe nea 126; of 484 gymnosperms 92; of Juniperus 31; of 61 Bot ne eins I ioe gor re cinia, ‘Miers on 158 Gardne Gates, R. > 72, 179, 477, 478, 479 — work 4 in 478, 47 Geotrop and metabolism, Grafe a nes on 480; perception ee Newcombe Gepp, A., soci of 396 Te aS. oe see m. iquet Gueninatae: in Cu tleria 383; in seeds of Xanthium under oxygen pressure 8 3°97 Gibsonia , Masse Giglio- Tos, ne ar of a ilg, E., of 157 Gleichenia, Boodle and Hiley on anatomy of 3 Goebel’s “Experimentelle Morphologie” 152 Gonolobus leianthus 296; macranthus a9 Grafe, V., work of 480 Graft hybrids, Pe ae? on 478 Grasses, gs on Cuban 309; ilger apr 158 Geaviy, infue ence on weedica of growth a 414 ee Herharice: contributions from 474 G eer ’s “Manual, »» emendations by Robin- son and Fernald 1 58 e, E. L., work of 2 Gre 396 Gresanuis q. M. 146, ae ee 309, 311, cology” (see Warming) Guatemalan plant 233; Eichlam on 157; undescribed 2 Girke, M. ppstehes of 157,3 Gymn osperms, evolution: tendencies practi we Hill and Fraine on seedling 314 Gritanenon fae Kern on 395 H Habenaria, a c of 242; mega- spores of 244; sie dees of 248 serrata G, work of 472 Hall, J. G Harrissella, Foweeit and Rendle on 3096 ler, E., work of 2 Hays’s. “A little Maryland garden” 309 eald, F. D., work of 395 Heating of leaves, Molisch on 318 INDEX TO VOLUME XLVII} [DECEMBER Hefferan, Mary 6 Heliocereus, Britton and Rose on 310 Hennings, P., work of 2 Heredity, albinism, Baur on 72; Darbishire on 47 28 in pea, Herter, W., work of 1 157 ae ee veered on 310 , T. G., work of 3 Hitchooc k, A. - wok ‘of 309 Holstia, Pax 158 pees nn’s ee wendeniete Vorle- ungen uber mechanische Probleme en des Botanik”’ 66 a J sie work of 158, 395 rold, ork of 2 Housed? S nes. Zoocciis” 308 House, H. D., work of 233, 234 Howe, M a tse of 1 Hurst, C. C., work of 471 Hybrids, chromosomes of Oecenothera 179; Giglio-Tos on 477; Rosenberg n Drosera 234; Winkler on graft 47 Hydrocyanic acid, Mirande on plants 480 Hylocereus, Britton and Rose on 310 Hypocreales, Seaver on 395 I no, S., work of 159 Impatiens Gilg on 157; Hooker on 158, se Otere of albinism, Baur on 72 Ipomoea, House on 234 Japan, onsedh of 234 Jehlia, Rose on 310 Jensen’s ““Haupilinien des _natiirlichen ee oe Johns n, J. R., work of 475 Jor cena ‘General bacterviogy” ee Julianiaceae, ovule of, Ker shaw Juni td gametophytes and ple ate in Justicia ee 300; Tuerckheimi- ana 3 Karsten and Schenck’s “ Vegetations- bilder Kary: okines in Oedogonium, Van Wis- sash Gn ase Keeble e. wack of 69 Kennedy, P. B., work of 2 32 ern, F. D., work of 395 Kershaw, Edith M., work of 319, 320 Koch’s '« Pharmakognostischer Atlas 466 Komarov, V. L., work of Pas Kostytschew, S., work Krakatau, Campbell on ton of 317 1909] Kranzlin, F., work of 158, 395 Kraschénniko ff, T., work of 240 usano, S., work of 75 — ium, americanum 3 “che 336; ene- ; rabenhorstii Larix, structure of wo 48 Lathyrus, Wooton aid aoe on 234 Leaves, Awano on wetting of 79; form tion of starch in 224; of gym nosperms 86; light and-concavity of 459; lisch on heating of 318; Smith on tem- perature of isolate Ledermanniella, eee on hg poe sae, Hassler Lemaireocereus, stead n pee Rise on 310 Laeacbls: W. W., work of 313 Leptocereus, Bri and Rose on 310 Light, and concavity - leaves 4593 Haberlandt on perception of 472; t Schiirhoff on perception gu 93 and protein synthesis, Zaleski on 400; and Paagioees n, Léwschin on 80; and varia- tion o ungi 5 Ligusticella, Coulter and Rose on 310 395 Ss hte & ise) ia) i) a 2 ee — ee aq Ling , Engler on 396 # tied K., work of 319, 480 as. B. 106 Lipm L fea. gaara on x 5 Loc work of 471 Locomotion : low temperature, Teodo- Potent. ‘Britt on and Rose on 310 Loranth Merrill on 395 Léwschin, _ work of 80 , work of @ oO n 233; Herter on of 1 385 sperms, c Lycopods, new “thee waletd genus 31 Lyon, Howard 44 M Macbridella 39 MacDougal’s North American deserts” 307 Mackensen’s ‘Trees and eee of San Macrogiuae conan on 157 Macrosporium Brassicae 15 Maige, Mme. G., work of 238 5 ee Botanical | features of INDEX TO VOLUME XLVIIf 485 Makino, T., work of 234 Malvaceae, Hassler on 233 Malme, G. O., work of 232 Marae, Eichlam on £57, 233 aple sap, pressure in py n development of fc) Mea ae R. 9 Mechanical tissue in stems, influence of traction on formation of 251 Megaspores, <= Calopogon 126; of Habenaria Merrill, ae Ds suede of 158, 395 Merwin, re trobus “wa n on a new genus of esoniecad oe opods 3 Metabolism ap geotropim, Grafe and Linsbauer Mexico, fortis of, furan on 310; plants of 158, 159, 232, er 234, Rose on 309; Williamsonias a Meyer, A., wor a Microorganisms, faders of electricity on Microspores of pend Pears 130 Milbraedia, Engler on 306 Milk, influence of eeiciy on bacteria in 363 Mirande, M., work of re a in Synchytrium Mobius’ s “Bo ‘ner? mas mabtroskoplaches Prak iekon Moffatt’ S "ighe fungi of Chicago region” 31T Molisch, H., ‘Das Warmbad” 155}; work of 31 rset morphology of 159 onostroma, — on 157 preci s N., work of 74 gaye oiaee Ruppia, a criticism of i E. work of 396 ,_Lepeschkin on mechanism Musc re R., “work of 234 Mycorhiza, Peklo on 237 N Nabokich, A. J., work of 476 Nakai’s “Blora Koreana” 1 N es, es, Saliebery o n extrafloral 79 Nectrieae, Seaver 0 158 486 ie Rago tote of 56 Neodreg Necnirs. ‘eee Pax on 158 eourbania, eect ind Rendle on 232 Newcombe, ¥. C., work of 76 Nilsson Ehle, He, "work of 470 North American flora 156 Nucleus of bacteria, gate! on 77 Nucleoli in Marsilia Rycoeeeie Britto n and Risse on 310 Nymphaeaceae, phere of 56 O Oedogonium, Van Wisselingh on 237 Oenothera, copier or of chromosomes 179 Olive, E. W., of 159 Coasters of Satie Tahara on 400 Orchidaceae, Cogniaux o aoa can 157; Bat Pa ‘ae Rendle on 232, 396; Finet olfe on 158; Bernard on in 474 sha sen of 146 Orias, Dode on 232 Ortherodendron, Makin 234 bose Coulter ae Rowe on 310 Osmotic press an permeability, réndl a Osterhout, V O si B. 159, 398 Ovule, gymnosperms go; — pares aceae, Kershaw on 320; ca, aw on anatomy og nae ee Widdein ia 161 gtoni Oxygen pressure and the germination of Xanthium seeds 387 Pace, Lula 126 Pachycereus, Britton and Rose on 310 Palicourea leucantha 295; mexicana 295 Palladin, W., wank of 79 Palla 5 ot work o . nimeflacene, Tschourina on 232 Pampanini, R., work of 2 32 andanus, Campbell on oe sac of 316 otton 400 —/ ! wie wet Laesare of 1 58 Parathes crocalyx 295 arish, S. B. 62 Pax, E. , work of 158, 23 ea, Da rbishire on heredity in 478 *échoutre’ s “Biologie florale” 393 eck, C. H., work of 396 G.J. eirce, Peklo, J., k of 237 Pelozia, Rose on 310 3 enaeaceae, Stephenson morphology of 315 Ste ’eniocereus, Britton and Rose on 310 INDEX TO VOLUME XLVII [DECEMBER Pe ereskiopsis, Eichlam on 157 Perithecium of Ascomycetes, Engler and Prantl on 6 Perkins, J., work of 158 Permeability Tréndle on osmotic pres- 18 Phanerosorus Copeland on 157 Philippine plants, Robinson on, 23 opeland « ON 234, 305; peed on ei sha re Merrill on 158 Phillips, F. F. J. 2 Phiyctochyttam shials 338; planicorne Shei ithe and electricity, Koltonski on 160 ee eine = roots, Linsbauer and Vouk o Phy Hlanthiinn Chinese on 234 Phyllosticta, variation in 13, 15 | y, of gymnosperms 82; of Juni- Passive, apparatus for plant 301 f 158 e of wood of 47; edulis, study of 2 an Be ati catenatum 294; sophoro- arpum Plankica: e Sececes on 233 Pleurococcaceae, ye Se ke on 232 work of 8 Porsch, Otto, work of 76 Peas: Potassium d sodium, similarity in behavior of 98, 106 Prantl, K., work of 67 Pro ochromogens, eae ae = 79 Proembryo, of Jun Protein and light oie bee "Tales a — hispidulum 299; ate paz Prcnddbasterdin, Hassler on 233 , Ga i ron 232 zia, Rose o as structure of rood of 48 m” urpus, J. A., work of ee 233 R Panaley ¢. “Wild flowers and trees of 154 a, Britto ose Rose on 310 Ranunc et Briquet 0 23 Reed, Geo Reimarochloa, “Hitchcock on 309 endle, A. B., work of 232, 39 Papen Maige on 238; and soe mentation, Kostytschew on 399; 4n light, Léwschin on 80 1909] Reviews: Bateson’s ‘‘ Mendel’s eet A peer 61; Beccari’s “Asia ms” 155; “9 Bas- et ake Moyen-Congo” 311 Bacterial!" ” ioe De orflers Botan Ein Sy Hays s it Maryland garden’ 300; Holtermann’s “Schwendener’s Vorle- ea tenon she Ider” och’s “ Pharmako pesoshachis © 466; MacDou ugal’s “Botanical features of North har ican deserts” 307; M kensen’s “Trees and shru ha of Sais poionm ” 355; Modbius’s staat 8 mikroskopisches _Praktik 466 Moffa tt’s “Higher fungi of, Ghicase region” 311; Molisch’s “‘Das Warm- bad” 1535; Nakai’s “Flora Koreana”’ h holzkunde” 312; Schrenk and Spaulding’s ‘Diseases deci forest en? 6; Seward’s “‘ Darwin and modern science” 308; Stahl’s “Biologie des Chlo phylls” 64; Strasburger’s “‘Zeitpu der Bestimmung des Geschlechts” 63 omson’s “Heredity” 62; Troup’ “Indian woods nd their uses” 31k; Van Rosenbu: rgh’s “Malayan ferns” = = pokes ming’s ‘‘Oecology of plants” 495 Rhipealis Novyaesii, Giirke on 157 Rhizidium bulligerum 3383 Sphaero- carpum 326 Rhizophidium ampullaceum 338; bre- Mes S322, 325; minutum 323; sphaero- 326 Riddle, O ©; ais of 472 7 Robinson, B. L., work of 1 ae 475 Robinson, C. B., work o. Roez] and the type of Washingtonia 462 INDEX TO VOLUME XLVII 487 Rolfe, R. A., work of 158 Roots, Linsbauer and Vouk on photo- tropism of 319 rk of 239 Rosenstock, E., work - : fe 396 Rubiaceae, ause 0 Ruellia humifusa aol: memes 298; pygmae Ranta rdia, Robineo on 475 Ruppia maritima, a eriticlans 228 Russell, H. L. 2 S Saccardo’s ‘“Chronologia della flora Italiana” 394 Salisbury, E. J., work of 79 Salix, Dode on z Salts, effects on ammonification by Bacillus subtilis 106 S AG ork of Sapotaceae , Smith on nig my o of 77 Sap pressure, in birch 442; in maple 446 Sargassum, idee of Tahara on 400 sey a aus Ww, out of I Schneider s “Handbuch "ag Laubholz- oe” 3r2 Sch hneider, J. M., work of 317 Ss cacak and Spaulding’s. “Diseases of deciduous Pgh trees” 156 work of 2 Schroeder, B 3 Schiirhoff, P., 79 Scion and stock, Griffon. n 320 citamineae Be aes n Philippine eee jation of 9 5 395 Seedlings modifiability of transpiration Seed, sof Ca lophyllum, Britton on 240; ing on chlorophy ll of 745 longevity eg cn iss on. Selinicereus, Britton & nd eee Senecio, How ellii lithophilus ss i schler 234 ries ria, va anion in 3, 12; Lycopersici 27 Setchellanthus, Brandegee o x in dioecious plants, Darling on 74 Sexuality of Keven and Ascophanus, n 39 poe *Baewik and modern science” —o oe 3 = of 396 Shul ck Shull Gar A. 3053 8 397: 466, 467 Sinnott, Edmund 8; work of 400 Ss. rt rom ont 138 Small, J. M., work of 396 488 Smilacina, embryo sac of 200 Smit h, John cio gr oe Sm ith, 15. HL; Smith, Winifred, geek SOF 77 and potassium, behavior of 98, 106 Solanum Rovirosan 297 Sohations, Benecke xe os 78 similarity in 233 pe ali, ae of 5 on chemotaxis of yycopodiu eT meager eared fy Seaver on 395 eR ge Steiner on 235 Spillman, W. J., work of 46 Spore igieteiaeuts of fungi, variability in 20 co We pir ae Se neal 64 Stam . eri s 89 Stan dley 5 AG Ges of 138, on 309 Starch, te leaves, ee ion of 2 Stein, Cacilie, w Steinbrin jee wor er mechanical — + 2 na oi i. E. L., work of 315 Steven ee Stock pa scion, Griffon on 320 Stone, G. East bur. urger’s s “Zeitpunkt der Bestim- des Ge peng! 63 Sivan: Stella G. Strobilus of soeteriee deer 86 typocaulon, Escoyez on centrosomes in 3 Sutton, A. W., of 470 Septees in Paci end on 474; algal- -animal, Keeble on 69 Symplocarpus, Ro piaiclall on 239 Ry siplocns. Brand on 395 Synchytrium, mitosis in 339 Sukatscheff, W., work of 234 Tahara, M., work of 4 Excess Se 15h 232, 30, 395, 474 Temperature, of isolated leaves, Smith on 73; ees on locomotion at low sn eodoresco, E. C., work om 240 he eetopar. Pohl on aoe Horold on American 232 homs n’s ‘Her acd 6 8 geB Hu c ‘S n and Rose on 309 3 ectroidea, Seaver Nn 395 thoni ampanini W. L. cae orae in a septate 50 ction, influence on 8g formation of pase actor a in stems 251 on eg SO acts’ SNE | = ya De 3 as 7 = poe | Gee fies. Breen. Sree, | » | rhs ot INDEX TO VOLUME XLVII! [DECEMBER 1909 Transpiration, modifiability in you "8 seedlings 275; ; Sampson and Allen o 3 Trichostelma, ciliata 296; oblongifolium 29 Trifolium, Kennedy on 232 Trondle, a work of ows $ “Tadian woods and their uses” Tschouring, O., work of 2 mboa, Pearson on Se a ek of 312 U Udotea, A. and E. S. Gepp on 396 e, E., work of 233 Umbelliferae, Boissieu on 395; Coulter and Rose on 310 Vv Sora th (see Warming) urgh’s ‘Malayan ferns” Venezuela, aga ton on ripe 5 Viola on 233 otuietis ae variation of 4, I1, 29 Vo rk of 319 beer 465 uk, V., wo W Warming’s “ Oecology of epee! 149, 465 re yom an _ wg type of 462 Watso 3 f 318 Webeucnens. Brian. ot Rose on 310 Widdringtonia, ovule, gametophyte, and mbry es Wei ingar wy. ork of 158 ein ba S Brittod and Rose on 310 Whildale, rant work of 472 Wieland, G 2 Wilcoxia, Briton ae Rose on 310 lle, N., work of 2 Williamsonias of the Tisteca alta 427 Wi sige , H., work of 72, ie hc. Wittrockiela, Wille Wood in Pinus, stricta e of 47 Wooton, E. O., kor 158, 234 Wright, ee 13 i work of 395 x Xanthium seeds, oxygen pressure and lads oo is oO f 3 7 Xyris, Malme on 232 x pee ee Shigéo 75, 236, 237, 380 t, influence of electricity on 372 Wisse ingh, va work of 2 233 Z Zaleski, W., work of 400 Zamia, atte on anatomy of 475 Zoosporogenesis in Aglaozonia 384