THE oS “BOTANICAL GAZETTE: : TO s : JOHN MERLE COULTER | i Be ee VOIR ( 2 ‘i ne ee os) SOLYSDECEMBER gly TABLE OF CONTENTS The archegonium of Catharinea angustata Brid. (Airi-- chum — bee plates I-VIITI and one takes place. In this process the cells of one of these longitudinal _ rows divide parallel to the outer wall, thus se acentralrow of cells (the canal row) surrounded ed by 4 peripheral cell rows. Later . oe of these peripheral cells divide, thus iconnaco cells of the 8 4 BOTANICAL GAZETTE [yuLy out 3 peripheral segments and originate a central cell. The central cell now divides into an outer and an inner cell. The latter is the first cell of the axial row. The outer cell grows considerably, and again the 3 peripheral segments and the inner cell are cut off The latter divides into an inner and an outer cell. Thus the second cell of the axial row arises just as did the first, and KUHN holds that all subsequent cells of the axial row are produced in the — same manner. In 1872 JANCZEWSKI (9) made a study of the archegonia - several mosses. He names 2 species of Sphagnum, Atrichum (Catha rinea) undulatum, Bryum crudum, Funaria hygrometrica, and Phas- cum cuspidatum. JANCZEWSKI’s account of the development of these mosses is very brief. He mentions only the chief points, and : gives no details. It is unfortunate also that the paper has no illus- trations. In regard to Atrichum undulatum, Bryum crudum, Funa- ria hygrometrica, and Phascum cuspidatum, his chief points are as follows: There is development by an apical cell with 2 uw a - faces, producing a few-celled structure which at this time cant ; be distinguished from a young antheridium. In the uppermos __ cell, which is to be the mother cell of the archegonium proper, th sae appear, = as ao. described for Andreaea, 3 oblique wall _ cutting off 3 pe al segments and forming a funnel-s 14] 7 ues to act as an apical cell, cutting off ale pee: nt rey state _ The number of canal i initials varies from 2 to 6 —_ cover cell may cut off 1, 2, or r3 peripheral segments bef / re a new canal, initial 1917] BRYAN—ARCHEGONIUM OF CATHARINEA 5 In 1884 Hy (8) summarized the archegonial situation in the Musci as well as in other groups. His paper is noteworthy only for its philosophical considerations. In a very general way he confirms the findings of JANczEwskI, but adds little that is new or convincing to the subject. - In 1895 CAMPBELL (2, pp. 201, 202) studied the development of the archegonium of Funaria hygrometrica. Here the first division separates a basal cell from a terminal cell, which is the mother cell of the archegonium proper. ‘In the latter 3 walls now arise, as in the Hepaticae and Andreaea, but in Funaria they do not all reach the basal wall, but intersect at some distance above it, so'that they inclose a tetrahedral cell, pointed below instead of truncate.” The tetrahedral cell makes the usual division into “‘cover cell” and inner cell. The latter now divides, forming the primary neck canal cell and the ventral cell. “‘The cover cell instead of dividing by quadrant walls has a regular series of segments cut off from it and acts as an apical cell. These segments are cut off parallel both to its lateral faces and base and thus form 4 rows of segments, the 3 derived from the lateral faces forming the outer neck cells, and the row of segments cut off from the base constituting the axial row of neck canal cells.” As to the further growth of the canal TON, SORE Ten so far as ld be det do not divide after they are first formed.” : GaveET (4) in 1897 undertook a ve-ezainination of the ole question of archegonial development i in the Bryophyta, the i inves- a | __ tigation covering numerous forms ae the Musci. In the latter group, kis char basen ae tke : _ ~present discussion, he mentions s species of Sphagnum, 2 of An- Preden the following members of the a a, Z | bec e : Summing up the m in points of his, sudy ( Gaver arrives . S : hein. at 6 BOTANICAL GAZETTE [JULY 3- La cellule terminale ne donne point de cellules de canal, pas plus chez les Mousses que chez les Hépatiques. 4- Les cellules de canal du col ont toutes la méme origine; elles provi- ennent toujours d’une initale détachée de la cellule mére de l’oosphére; il n’y ena point d’adventives qui seraient formées aux dépens de la cellule terminale. GAYET’s conclusions, therefore, are diametrically opposed to those reached by other investigators. In 1898 GOEBEL (5) gives a rather brief and unsatisfactory account of his examination of Mnium undulatum. He states (p. 17): ‘I find in this plant confirmation through- out of the statements of JANCZEWSKI and others, and that the archegonium of the Musci is to be dis- — tinguished from that of the Hepaticae by its peculiar — apical growth” (text fig. 1). The cell represented — as apical in this figure is most certainly not the one — described by JANcZEWsKI. GOEBEL’s illustration | would lead us to believe that the canal row has been — formed by the activity alone of the one cell marked +. formation described by Janczewskt. Hence GOEBEL must be entete as giving an ans? different : im reproduced once, and fig oon greece cell adding to the < do : 1 from Gorser’s row. In 3 other archegonia he shows the t topmo : ee Sem canal cell i in the ‘Process of Len while i in one case 1917] BRYAN—ARCHEGONIUM OF CATHARINEA 3 8. The terminal cell adds to the growth of the neck by segments cut from its 3 lateral faces, and to the growth of the axial row by segments cut soe its truncate face. Growth in length of the archegonium neck is intercalary as well as wie in both neck and canal.rows. SERVETTAZ (13) in a quite recent physiological paper on the Musci includes an investigation of the development of Phascum cuspidatum. ‘The developmental story is given briefly as follows (p. 271): La cellule initiale se cloisonne transversalment et donne une cellule de peid, “‘a,’”’ et une cellule supérieure ‘‘b’’; la cellule ““b”’ se cloisonne ensuite obliquement un certain nombre de fois (2-5) comme s’il s’agissait de consti- tuer un bourgeon végétatif ordinaire, puis l’une des cellules placées au-dessous de la cellule terminale se divise tangentiellement et détermine la formation d’une cellule central “‘c” qui, par des cloisonnements basipétes, donne une file de 8 cellules qui seront: 1-4, les cellules du canal; 5, la cellule du ventre; 6, Poosphere. ... Quant 4 la cellule terminale, ey s,” elle peut continuer A se diviser et elle forme la calotte recouvrant l’extrémité du col. En definitive, le mode de formation que nous venons de décie se rap- proche de celui que Goebel a décrit pour Mnium undulatum. _ The evidence offered in support of this developmental story is _ Certainly too meager and not sufficiently critical to be convincing. - Moreover, the origin of the central cell, or first cell of the axial row, __ _ by a tangential division of one of the segments below the terminal cot f is a k revival of the HOFMEISTER Conception: which mpegs ao "nw oem @) dapemansasnaatan the archegonium ; of S Te sections both transverse CS a cle) Wicca Hide ‘had of the other Musci ce 8 BOTANICAL GAZETTE [JULY make it certain that the growth of both canal row and peripheral cells of the neck is intercalary and not apical. SUMMARY In regard to the formation of the archegonium proper in the Musci 3 theories have been advanced: (1) the HOFMEISTER con- ception of the tangential division of one of the 4 original pedicel rows, a theory soon made untenable by the work of later investi- gators; (2) a recent revival of the HorMEISTER scheme modified by the tangential division of one segment only, as proposed by SER- VETTAZ; (3) the commonly accepted account, confirmed again and again for all the great groups of the Bryophyta, namely, the appear- ance in the terminal cell of 3 oblique walls forming 3 peripheral segments and an axial cell within. It cannot be maintained, therefore, that the origin of the archegonium proper is in doubt. The evidence is too overwhelm- ing to admit of any uncertainty on this point. However, the development of the axial row is another matter. Here is a subject involving widely conflicting accounts, some being diametrically opposed. Summarized, these accounts are: (1) the abandoned conception of HorMEISTER, having only a historic interest; (2) Kitun’s claim for Andreaea that all the cells of the axial row are cut from the base of the apical cell; (3) CAMPBELL states for Funaria _ that the axial row is composed of a primary canal cell and seg- ‘ments cut from the base of the apical cell, none of which divide — after they are formed, so far as could be determined; (4) GorBEL holds that in Mnium undulatum the topmost neck canal cell (the ‘one just below the cover cell) acts as an apical cell in the produc- — - tion of the canal row; (5) Janczewskt finds that the cells of the axial row are of diverse origins, the upper arising through trans- — _ verse divisions of the 2-6 initials cut from the base of the apical cell, while the lower are formed by the t jons of the inal initial; © Hotrerty has shown ‘that the growth in : - the canal row of Afni um Ch o (7) Gavet concludes that, the canal cells among the Musci have S all the s same ae : that there are no segments cut from the oe : 1917] BRYAN—ARCHEGONIUM OF CATHARINEA 9 initial produced by the mother cell of the egg; (8) SERVETTAZ states that in Phascum the canal row is formed by the basipetal divisions of the central cell; (9) the author has shown by division figures that in Sphagnum subsecundum the growth of the canal row is entirely intercalary. It is evident that the Bryales are in need of a reinvestigation, not a superficial examination of many forms, but a careful inten- sive study of representative forms showing as far as possible by actual division figures the course of development. It is with such an idea in mind that the present work has been undertaken. Development of archegonium The apparently dioecious Catharinea angustata here studied produces a fairly large number of archegonia on each gametophore. The count shows variability with an average of about twenty. As previously stated, young archegonia begin their appearance early in April, and by the middle or end of May the majority © have reached maturity. The first archegonium arises from the apical cell region, but whether from the apical cell itself or from one of its immediate segments cannot be stated positively at present. The study of the behavior of the apical cell in the pro- duction of archegonia and the continued growth of the gameto- _ phore, if fertilization does not occur, must be reserved for a later — paper. Tn its hy § stages tk a DY the usual eB 1ethod of an apical I cell with t vo cutting ; faces (igs. 1335, 7-9). . n the 1. an Wawa ween a ce oe eptions to ; this statement have been found a 2, 6). “In both cases. a young ir very crowded quarters, being ps chsely surrounded by the stalks of archegonia nearing maturity. _ Be ‘After a variable number of segments, — = have been oo the apical « ell ua UY | - 10 BOTANICAL GAZETTE [JULY for Funaria, but extend to the basal walls. The primary axial cell, therefore, has something of the shape of an inverted, truncated pyramid. There now follows the division of the primary axial cell into an outer axial cell, the cover cell, and an inner axial cell, the central cell (figs. 12, 13). Quite soon the central cell divides. the resulting lower cell being the ventral cell, while the upper is the primary neck canal cell (figs. 14, 15). The actual division of the central cell was found twice. The axial row of the young archegonium now consists of the ventral cell; its sister cell, the primary neck canal cell; and a large cover cell (figs. 15-17). : It is interesting to note that in fig. 15 the original division wall between cover cell and central cell appears tilted, due partly to the inequality in the growth of the peripheral segments, and partly to the change in the direction of the axis through the formation of new peripheral segments by the apical cell. While this tilting is — not always found, it is of frequent occurrence, as shown to a greater or less extent in figs. 16, 18, 20, and furnishes valuable evidence in separating that portion of the axial row derived from the central cell from the part contributed by the cover. The cover cell now cuts off peripheral segments ns 15-17). No absolute Proof can be given as to their exact number, but it series as figs.15-18 that there __ are e3 peripheral segments. Then there is added to the canal row an initial cut from the base of the cover cell. The evidence for this statement rests on fig. 18, on several others quite like it, and __ : is corroborated by the figures in the series about it (figs. 16-20). similar series could be constructed from the material — oe Sears A Jong and careful search failed to reveal the actual | division figure, but in fig. 18 the size and position of the nuclei and _ 2 z the delicate wall between leave no doubt that the uppermost canal |) ow consiéts of the ventral cell; its sister cell, the primary r a >I] has t cut from t base of the cover cell and that the: process a has just: been completed. As illustrated by fig. 19 the axial Tow canal cell; an initial cut from the base of the cover cell; and a large ae : . cover cell or apical cell. Up to this point the | process of development i is ae and deh ease Meee tee ability shockir 1917] BRYAN—ARCHEGONIUM OF CATHARINEA II one save an old-fashioned, rigid morphologist. After the first initial has been added to the canal row, the apical cell again begins to cut off peripheral segments (figs. 20, 23), but in the meanwhile the periphery is also growing by intercalary divisions (figs. 10, 20, 22). While these peripheral processes are going on, the cells of the neck canal row are not inactive. The primary neck canal cell may divide first (figs. 20, 21), or the initial cut from the base of the cover cell may make the first division (fig. 22). That there are intercalary divisions in almost any order at this stage of the process may clearly be seen from the series represented by figs. 25-28. The archegonium has now reached the stage when it con- tains 4 or 5 neck canal cells. At this time the evidence is positive that the cover cell adds a second initial to the row of neck canal cells (figs. 29, 31). Fig. 29 illustrates excellently the intercalary as well as apical growth of the archegonium. — While fig. 31 is of interest in showing the activity of the cover cell in adding an initial to the canal row, it has an additional inter- est in giving evidence as to the origin of oblique walls in the axial row. The axis of the spindle is tilted and an oblique wall is being formed. In fig. 32 the process has been completed and the result is very evident. There are then two ones eae the oblique walls ee in the canal row. The first we have fig. 15. No reliable evidence could be found that these walls might arise in any other way, such, for example, & as the iepercniney ee _ division of a canal cell. As a result of inter o _ activity the canal row now contains 5~7 canal cells. that follow there is no definite sequence that can = oyster statement that can be mz de 1S 1 -* canal cells eased by intercalary aie es ie, as: VFS - Just how active the cover cells at this time cannot the stated, . ap I2 : BOTANICAL GAZETTE [JULY Fig. 48 shows the formation of what is probably in the majority of cases a last initial cut from the base of the cover cell. Abun- dant evidence has been found that at some time between the 12-16 neck canal cell stage the cover cell changes its manner of division and segments by a wall perpendicular to its base into two more or less equal parts (figs. 50, 51, 54, 56). The division figure was found once and is shown in fig. 56. No evidence could be obtained that the division may occur before the 12 neck canal cell stage; while after the 16 neck canal cell stage practically all covers showed division. Out of the large number of cases studied only two excep- tions were found, one a case of 18 neck canal cells, and the other a case of 20 with the cover in each yet undivided. Such a process, then, while occurring within general limits is by no means fixed. Whenever such a division does occur, it signalizes the end of all true apical activity. The segmented cover stands out well defined from the peripheral segments of the neck and its history can be followed for some time with a reasonable degree of accuracy. Thus in figs. 61 and 62 the cover cell has formed 6 segments (3 shown in median longitudinal section) and is literally the cap of the archegonium. In fig. 72A we have the cross-section of the _ cover of an archegonium containing 35 neck canal cells. It shows 7 clearly the primary: division es I-I}; the Lowap walls 2-2; and th d When the archegonium is fully matured the sepments oF the cover merge insensibly with those of the neck, hence an exact statement cannot be made as to the final number produced. | : o The division of the ventral cell into ventral canal cell and egg ae found five times, 3 being shown (figs. 47, 50, 53). Here again : ‘ one finds the same sort of variability noted for the cover cell, but — - with a slightly greater range. The division may occur as early as the rz neck canal cell stage (fig. 47), while several cases were __ found in which there were 17-20 neck canal cells sath the Yentet yet : ae / : undivided (figs. 58, 60). The ventral canal = _ division is quite variable in size. Sometimes it is about the : shine se ‘size as the egg (figs. 56, 6, 68); or it aay. ae Botiecably smaller G54, 3,68). _Asalready stated, the cutting off of initials from the base of the s | one elem se eaneey of cases brought to a cx : : : canal row in all of the cases observed was acro] 1917] BRYAN—ARCHEGONIUM OF CATHARINEA 13 where between the 12 and 16 neck canal cell stages; but since the undivided cover cell may be found as late as the 20 neck canal cell stage, it is evident that a variable number of initials may be cut from its base. We have given proof that at least 3 initials are produced, but we can make no positive statement as to the maximum number. By making due allowance for the rapid intercalary growth, we should estimate that in the majority of cases the number does not exceed 5 or 6. Whatever may be the number of initials, the fact remains that both the canal row and the peripheral cells of the neck continue to grow by intercalary divisions. Figs. 45-61 show some of the many divisions found and furnish ample proof for the statement. This continued intercalary growth finally produces an astonishingly _ large number of neck canal cells. In the material studied the average count is well over 50; frequent examples in the sixties were found; two in the seventies (one with 74 and the other with 76 neck canal cells); and finally one example in which there were 86 neck canal cells with several of the basal neck canal cells just beginning to disintegrate. Not only is the number of neck canal cells large, but the canal row is generally multiple in its upper part (fig. 65). Less often this multiplicity is found through the middle portion of the neck (fig. 66) and in the basal part of the canal row (fig. 68). We have interesting evidence from fig. 64 that this _ multiple condition may arise by ie simultaneous division of the ° | ee cells con . 7. stad of cross-sections through mature archegonia 1 the * oe some interesting facts. A rey terminal Opes te Sak G tho ne 69A-F. The canal row te not - oS merely double i in this Portion: but generally consists of 3. cells and — e peculiar enlargement of the canal at its oe upper end is well shown by figs. 65, 60. The breaking down of the opetal, but did not oe is latter cell persists { for some: 4 time, oe its s history up to o featon has not been followed as oa ium is not uniform Soe - mu BOTANICAL GAZETTE [yoxy two cases were found, one being illustrated in fig. 70. The arche- gonium here contains 17 neck canal cells, 3 of which are shown, and has 3 cells in the venter. It seems probable that the 2 lower ones were formed by the division of the egg, while the upper is the ventral canal cell which has remained undivided. Fig. 71 is the reconstruction of a very remarkable double archegonium. It may have originated by the fusion of 2 very young archegonia, or by the longitudinal instead of transverse division of the primary axial cell. Discussion Catharinea undulata has been studied by JANCZEWSKI only. The present work on the closely related C. angustaia confirms in general his statements, especially in reference to the origin and development of the canal row. There can be no doubt that the cells of the neck canal row in C. angustata are of diverse origins. The lower arise through intercalary divisions of the primary neck canal cell, while the upper are produced by the intercalary divi- sions of at least 3 initials cut from the base of the cover cell. Aside from the activity of the cover cell, there is no evidence that any one neck canal cell may act as an apical cell in the develop- _ ment of the canal row. On the contrary, the evidence is clear that os any cell of the neck canal row may divide and in any order. This process is also in general agreement with the findings of HoLFERTY ce for Mnium cuspidatum, where both apical growth and intercalary __ divisions are reported. If Campsext is correct, Funaria shows a_ __ striking difference, in that the primary canal cell and the initials cut a from the base of the apical cell do not divide after they have been. f f - ormed; while GOEBEL’s account for Mnium undulatum shows still oa urther difference, in that one of the neck canal cells at the apex of Th S _ the canal I cell 2 d by its activity produces the oF ] - further growth of the canal row. “a these differences are oe : = _ firmed, Latex acake saasaews — g series in "The facts i in ‘the present paper pe an eophatic decal of . — the swe lizz : 2 : pecenee give rise to neck canal cells. While the author has ce shown in a previous Paper that in Sphapwum subsecandnem tion of GavET that among the Musci_ the | : 1917] BRYAN—ARCHEGONIUM OF CATHARINEA 15 initials are added to the canal row by the cover cell, this investi- gation makes it certain that in C atharinea angustata at least 3 initials are produced. Just what type of development the representatives of other groups of the Bryales will show remains to be seen. Conclusions The archegonium of Catharinea angustata grows for a time by apical as well as intercalary divisions in both canal row and periph- eral cells of the neck. In its later stage the entire growth is inter- calary. The cells of the canal row have a double origin. The lower are formed by the intercalary divisions of the primary neck canal cell, the upper through the intercalary divisions of the 3 or more initials cut from the base of the cover cell. How general this condition is among a Bryales must await setipad work. A 1. The archegonia of Catharinea angustata begin to sities Se April. a. The first formed archegonium arises from he apical cell region, but whether fron the apical cell itself or from: one of its” pe immediate. segments must be determined later. _ oS 3. In the ERGY shies ad Govelinunca the eeweg ecbagoaturn a one and | oe primary axial oll gong which on "division oS gies te 6 Dee toler Gall sind the anand eel. oe s ns aie conten call 00 division = rm he rinary ack ct = 16 BOTANICAL GAZETTE [JULY 8. The cells of the canal row and the peripheral cells of the neck grow by intercalary divisions, and in any order. 9. The major growth of the archegonium is intercalary. to. The cells of the neck canal row have a double origin. The lower are formed by the intercalary divisions of the primary neck canal cell; the upper through the intercalary divisions of the 3 or more initials cut from the base of the cover cell. 11. The ventral cell divides relatively early into ventral canal cell and egg. 12. The ventral canal cell is variable in size. 13. The mature archegonium has usually more than 50 neck canal cells, and may contain as many as 86. 14. The canal row is generally multiple in its upper part and occasionally throughout. 15. The disintegration of the canal row is acropetal, but does not involve the ventral canal cell. 16. If the number of neck canal cells is an indication of primi- tiveness, the most advanced group of the mosses has the most primitive archegonium yet described among the Bryophyta. UNIVERSITY OF WISCONSIN 1. BRYAN, GEO. ‘S., The t ium of sors bs lum. Bor. Gaz. — $9:40-56. pls. 4-7. 1915. 2. CAMPBELL, D. H., Mosses and ferns. New York. ‘1905. 3- CHAMBERLAIN, C. J., Methods in plant histology. Chicago. rots. : + Gayvet, L. A., Recherches sur le développement de Varchégone chez les - Muscinées. = Sci. — Bot. VIII. 3:161-258. ag 7-13. eile 5. GoEBEL, K., Sapecwreand of plants. Oxford. 190. 6. Ho a a = V Reiman, Ents . und F 1 ee eg oe | - T eipzi 7. Hoxrerty, G. M., The Pee of Mnium Baa Bor. Gaz. -372106-126. pls. 5, 6. 1904. | 8. Hy, F., Recherches sur Parchézone ct le dé ppement du fruit a cinées. Ann. Sci. Nat. Bot. VI. 18:105-206. pls g-r4- 1884. Ceo o “p- Janczewst, E — Vergleict iiber die Entwick- lungsge te Sn Bot. eit. 3 30137-3903, mE, ro. eh naa t ag gsgt hick der Andreacaceen. ‘Schenk und os nem gebe F Botanik. 4:51. a 1917] BRYAN—ARCHEGONIUM OF CATHARINEA 17 11. Lanp, W. J. G., Microtechnical methods. Bor. Gaz. 59:397-401. 1915. 12. SCHIMPER, W. Pu., Versuch einer Entwickelungsgeschichte der Torfmoose. Stuttgart. 1858. 13. SERVETTAZ, C., Recherches expérimental sur le développement et la nutri- tion des Mousses en milieux stérilisés. Ann. Sci. Nat. Bot. [X. 17: 111-223. pls. 1-4. 1913. EXPLANATION OF PLATES I-VIII All figures were drawn with the aid of Abbé camera lucida at table level, and, being reduced one-half in reproduction, now show the following magni- fications: figs. 1-27, 870; figs. 28-35, 64-68, 700; figs, 36-44, 63, 690, 70, 72-74, X550; figs. 45-62, 410; fig. 71, X 225. Abbreviations are as follows: a, base of older archegonium; /, leaf; p, paraphysis. PLATE I Fic. 1.—First archegonium arising from apical cell Fic. 2.—Young archegonium with abnormal cross walls ‘ising at base of ac archegonia. Fic. 3.—Typical development by apical cell with 2 cutting faces. Fic. 4.—The same, slightly older. Fic. 5.—The same, still older. ‘ Fic. 6.—Development by walls which do not quite intersect; bases of» older archegonia seen on each side of young archegonium. ae Fic. 7.—Typical ieee older stage. _ Fic. on Fic. 9 lation t ] well shown. Fic. 10—First archegonium arising ‘from apical cell region which has now seg larly in terminal cell the first of the 3 oblique walls origi- . 2 etal a ag ee ae HA t1--Tn terminal coll the 3 oblique walls heve:c t off per cet ae "fests pul foc etary axial col wehin. _ Fic. 12.—Primary : axial cell has divided into cover cell and central cell eS ae _ Fic. 13.—The same, Fic. 14.—Central cell dividing to form ey neck canal call and ven- ee tral cell. a Fic. 15—Division of central cll has just ben completed cover cell has : noel es a : ei Pee Bo su Pe Pins ca cl Fe ihe same; cover cell has formed = ress segm: 18 BOTANICAL GAZETTE [yuny Fic. 20.—Two neck canal cells and ventral ote cover — forming a periph- eral segment, while primary neck canal cell is in Fic. 21.—Two neck canal cells and ar ac paieery neck canal cell in divisio: es 22.—Two neck canal cells and ventral cell; first initial cut from base of cover in division. G. 23 Lg SRG IRE VE ery | ai pe re 1 lI a °. Poe, al eral segment Fic. 24.—Three neck canal cells and ventral cell. Fic. 25.—Three nee canal cells and ventral cell; middle neck canal cell in division. Frc. 26.—Three neck canal cells and ventral cell; topmost neck. canal cell in division. _ Fic. 27.—Four neck pane cells and ventral cell. PLATE III Fic. ee neck canal cells and ventral cell; second neck canal cell from ventral cell in division. Fic. 29.—Four neck canal cells and veopeal cell; simultaneous division | pe ond pen ek oe while Cowes: cel AO@ 6 reve Metial to Fic pan Tr, come ° 1 4}. me | ‘ut W Lay oe a . . 1 segment. - Fic. Stour neck cna ls nd venta cl cover cll ang second ges age ce ee — carom ase af cover cl ; eee - ce "Fic. 35-—Five neck canal ells and ventral el; second neck canal cell Pec 34-—Five neck canal cells ad ventral cell; stop 10S! “Fic. o-Sewek can role ead sential oa : : . Ne. ees —_ canal cells and ventral cell; pet 5 ck canal | lel sees) BOTANICAL GAZETTE PLATE V LXTV E, BOTANICAL GAZETT < A F Fre, SLOSS a we! + Be, A) x [ololoforeters Ger { DSL CO | Pes >\0\> Vie : poo cre - fe ge Ge eH, ORAS: PLATE VI LXIV , BOTANICAL GAZETTE Ty ed 3 aes - ets sy ae a. (Vall 5 Ge : ek. ee nr es al Coahuila, Mexico, September ara, 1904 ene in | Herb. NY. Bot. Gard). Differs from B. procera Don in having ach oe tert. es ore aes ee From B. se Sosiaigons 26 BOTANICAL GAZETTE [JULY characters respectively constant. This being true, it seems certain that the 15 or more beautiful plants collected by Palmer (no. 419), and all of them having Lersca 4 elongate, very attenuate achenes, are likewise specifically distinct Bidens pseudalausensis, sp. nov.—Herba, verisimiliter annua, circiter 6 dm. alta (ex Langlassei inscriptione), ramosa; caule et ramis tetragonis et acute angulatis, striatis, glabris. Folia opposita, petiolata, petiolo adjecto 2~7 cm. longa, 1-5.5 cm. lata, bipinnata, glabra; ultimis lobis cuneato-oblanceolatis, dentatis dentibus ad apicem induratis; petiolis o.2-2 cm. longis, ad basim connatis, Capitula terminalia, tenuiter pedunculata pedunculis 1.5—-6 cm. longis, ligulata, ad anthesin 6-7 mm. alta et (ligulis adjectis) eirc. 1.5 cm. lata. Involucrum basi glabrum, squamis duplici serie dispositis; exterioribus (circ. 8) linearibus, ciliatis, 2-3 mm. longis; interioribus paulo longioribus, glabratis, margine diaphanis. Ligulae (circ. 5) albae (e Langlasseo), in sicco specimine luteolae, striatae, obovatae, ad apicem lobulatae aut obtusissime dentatae, §-7 mm. longae. Achaenia (1-3 maturata in capitulis singulis) linearia, nigra, faciebus plus minusve glabra, marginibus tuber- culato-hispida, biaristata (aristis sub apicem retrorsum hamosis), _7-9mm. longa.—Differt a B. alausensi H.B.K. habitu ramoso, etc. -_ E. Langlassé 541, at altitude of 580 m., “El Ocote, Cerro Pedregoso, Michoacan and Guerrero,” Mexico (type in US. Nat. Herb.). - ‘Bidens aequisquama (Fernald), comb. nov.—Bidens rosea Schz. Bip. var. aeguisquama Fernald, Proc. Amer. Acad. 43:68. 1907- This rare species differs very markedly from Bidens rosea Schz. Bip., not ee only in its involucres but also in its foliage and achenes. The type of B. | rosea (Cosmos pilosus H.B.K.) is still extant (in Herb. Mus. Hist. Nat. Paris) _ and, though rather i immature, is not separable from such specimens as Heyde and Lux 6172 and Palmer 192 i Coes, Proc. Amer. Acad. 41: _ the type species of that genus (Cosmos 1917] SHERFF—BIDENS 27 conspicuous, averaging } to 3 the length of the achene body, and are armed with many retrorse barbs that are not deciduous. Many other characters likewise are pronounced, making it seem best, therefore, to give herewith a full specific description, drawn from the type and various cotypes examined. BIDENS AEQUISQUAMA, descript. amplificat——Herba, +5 dm alta; caule ramisque pubescentibus aut subglabris, quadrangulari- bus, striatis. Folia opposita, petiolata, petiolo adjecto 3-8.5 cm. longa, indivisa aut tripartita, ciliata, supra subglabra, infra sparsim adpresso-hispida et pallidiora; indivisis foliis lanceolatis, subcrasse setratis; foliolis foliorum tripartitorum similiter serratis, terminali- bus ovatis aut lanceolatis, lateralibus ovatis et subsessilibus et minoribus; petiolis o.4—1.8 cm. longis, hispidis, ad basim connatis. Capitula terminalia, ligulata, pedunculata, pedunculis 1-6 cm. longis et ad apicem creberrime albido-pubescentibus. Involucrum basi hispidum; squamis duplici serie dispositis; exterioribus (9-16) linearibus, hispidis, 2-4 mm. longis; interioribus subaequalibus, lanceolatis, glabris aut ad apicem et longitudinaliter medio hispidis , margine diaphanis. Ligulae (circ. 8) roseae, striatae, apice irregu- lariter 2-4-dentatae, 9-11 mm. longae, 6-8 mm. latae. Paleae lineares, margine diaphanae, 4-6 mm. longae. Achaenia nigra, linearia, ad apicem plus minusve hispida, biaristata, aristis non adjectis 4.5-7 mm. longa, flavis aristis retrorsum hamosis et 2.5-3 mm. longis. “BIDENS SEEMANNIL”’ Seis. Bip ex Seem. Bot. Herald 307. 1852-57; Cosmos Seemannii Gray, Proc. Amer. Acad. 19: 16. 1883. SCHULTZ ees beli of separate treatment and accordingly Je united it with Bidens. s ok d th ey tu unworthy But since his time, | — of the Compositae have per- as sisted very uniformly in recognizing Cosmos as a distinct genus — _ (cf. GREENE, Pittonia 4: 245. eon Indeed, the characters of : ee s Cav.) areso 4 Sree ice ke 6 ay went ak Senn Boe | : __Bxos’ view wil ever be accepted by botanists inthe future. This. 28 BOTANICAL GAZETTE foxy in a number of Cosmos species is the rostrate achenes. Cosmos bipinnatus Cav., C. parviflorus H.B.K., C. caudatus H.B.K., C. sul- phureus Cav., and C. ocellatus Greenm. are among those species dis- playing this character in a marked degree. A study of such species shows that the rostrate achenes are accompanied in almost every case by two other characters; namely, some shade of red in the ligules and the appearance of the interior involucre in the somewhat immature heads, suggesting the conspicuous inner involucre found so commonly in species of Coreopsis. But there are a few species of Cosmos in which the mature achenes tend to be erostrate. Thus, Cosmos crithmifolius H.B.K. and C. linearifolius (Schz. Bip.) Hemsl., in the many specimens that I have seen, fail almost uni- formly to exhibit achenes swollen below and distinctly long-rostrate above as in C. bipimnatus. Yet in color of ligules and character of involucre they harmonize perfectly with Cosmos. While neither of these two characters is absolutely diagnostic, their simultaneous occurrence, coupled with a tendency of the central achenes at maturity to be elongate, even though indistinctly rostrate, shows both species to be true Cosmos beyond all question, and not Bidens. Hemstey (Biol. Centr. Amer. 2: 203. - 3882), in dealing with the Compositae of Mexico, very correctly considered these two species as belonging to Cosmos. But “Bidens Seemannii,” a species so identical generically with Cosmos crithmifolius that _ Hemstey himself erroneously referred to it Parry and Palmer 485 (true C. crithmifolius), he retained as Bidens. At a later date Asa Gray suspected Ghiesbreght 264 of being “Bidens Seemanii”’ and stated that, if it was, the name should become Cosmos See- mannii eee Amer. Acad. =* 16. 1883). In Gray Herbarium, the ¢ breght | tudied by Gray is still preserved in S pee Ss ideniical with Seemann 2or4 (in Herb. — Kew), thus ction Gray’s supposition. It is accompanied bya letter to Gray fron HEMSLEY, peters must have been written _ a : Foren 1881 and Beha: ‘later than citi Ube « dates. of eae oe 1917] SHERFF—BIDENS 29 GREENMAN (Proc. Amer. Acad. 41: 265. 1905), relying upon the erostrate achenes, retained ‘‘B. Seemannii” in Bidens.. But, as might be inferred already, if this treatment were to be adopted, then the subgeneric congeners of this species, such, for example, as Cosmos crithmifolius, would likewise have to be placed in Bidens, a procedure that surely would meet with little acceptance, if any. Thus it seems best to follow the views of Gray and Hemstey in this matter and treat the species as Cosmos Seemannii (Schz. Bip.) Gray. Besides th f C. Seemannii listed by GREENMAN (loc. cit.), [have examined the followitig: J. N. Rose 3435, in the Sierra Madre, near Santa Teresa, Terr. de Tepic, Mexico, August 11, 1897; Dr. Edward Palmer 1852, Tepic, Terr. de Tepic, Mexico, January 5—February 6, 1892; Arséne, Cerro San Miguel, Morelia, Mexico, February 1909. “BIDENS PaLMERI” Gray, Proc. Amer. Acad. 22: 429. me This species, with its strongly ribbed leaves, is very close to Cosmos crithmifolius H.B.K., but cats in its oneal rays and slightly different leaf outline. In most the achenes are clearly erostrate, but occasionally some ‘of gral central achenes become highly elongated above, appearing almost distinctly. rostrate and thus exactly simulating those of such species as Cosmos crithmifolius and C. linearifolius. This is especially no-— table in certain material collected by Barnes and Land (nos. 164 — and 189, in Herb. Field Mus.). In fact, the subrostrate character ee of the achenes was known to Gray (cf. Gray, loc. cit., “ acheniis subulatis ... subrostratis ”). Yet, curiously enough, he placed. this species in Bidens, while previously (Proc. Amer. Acad. 19: 10. eS as shown : above, to to the Chiact ght 5 it, described = himself as. wigs ae 30 BOTANICAL GAZETTE [yuLy altitude of 1525 m., Rio Blanco near Guadalajara, Jalisco, Mexico, October 6, 1903; C. R. ga and W. J. G. Land 164 and 167, at altitude of 1707 m.» Sierra de San Estaban, Jalisco, Mexico, September 28, 1908; idem 180, at altitude of 1737 m., Sierra de San Estaban, Jalisco, Mexico, September 28, 1908. BIDENS TENUISECTA Gray, Plant. Fendl. 86. 1849; Bidens cognata Greene, Leafl. Bot. Crit. 1: 149. 1905. In describing Bidens cognata, GREENE (loc. cit.) stated that it was “‘allied to B. heterosperma.’’ He then proceeded to differ- entiate it from that species, which was very easy to do because B. heterosperma was so unlike it. Here, as in certain other cases (cf. SHERFF, Bot. Gaz. 56: 494. 1913), GREENE’S error consisted 20 Soe: the plant to the wrong species and then founding a upon the points of dissimilarity. His type material o. B. Metcalfe 1436) is merely a low, rather much branched form of Bidens tenuisecta Gray, with the type of which (in Herb. Gray) it is connected by numerous specimens in American herbaria. “Brpens DILtentana’”’ Hill, Veg. Syst. 3: 123. 176r. This name seems to have escaped the serious attention of botanists for more than a century anda half. The Index Kewensis, although it cites the name, does not cite the habitat. Hiri himself (loc. cit.) called it the “dwarf hemp agrimony” and stated that it was a British n plant (“a petty plant of our own country’’), but his g tration and brief description were entirely too vague for satisfactory determination. However, on turning to his earlier work (Brit. Herb. 461. 1756), we find (under Ver- besina) a much fuller description of the dwarf hemp agrimony, along with descriptions of what are now known as Bidens cernua L. and B. tripartita L. This description and the earlier name oe cited there by Hit, Verbesina minima Ray, show positively that the plants later named Bidens Dilleniana were merely the dwarf bog form of Bidens tripartita L. or the similar form of B. oe : cernua L. - very a both these forms without distinction). oe was given evidently for the very reason __ i - pane (Cat. Plant. Giss. 167, App. 66. 1719; ex Ray, ee Syn. eae pl. 7. fig. 2. : Flos was the one to introduce the name 1917] SHERFF—BIDENS 31 Druce (Fl. Berks. 283. 1897) has treated the dwarf form of this species as “forma minima.” But it should be noted that Drutce is not the first author to adopt this status, Larsson (FI. Werml. 221. 1859) having used it long before. Similarly, the dwarf form of B. cernua L., named “forma minima”? by Druce (Herb. Dillen. 67. 1907), evidently under the impression that such treatment was new, was already described, years before, as B. cernua {. minima (Larss., loc. cit., 220). BIDENS CERNUA L. Sp. Plant. 832. 1753; Bidens Kelloggii Greene, Pittonia 4: 267. 1901. A careful study of the type and other cited specimens of Bidens Kelloggit (in U.S. Nat. Herb.) shows them to be incapable of separation from B. cernua. GREENE classed these forms among the segregates from B. laevis (L.) B.S.P., but most a so, for, at the same time, he even stated that ‘‘Dr. Torrey . ‘ more correctly referred them to B. cernua.” It may be remarked in passing that, in the future, es : new species allied with Bidens cernua should be described only after taking the utmost care to see that they are not mere atypic forms of that species. It would be interesting | to subject B. cernua to elaborate breeding experiments. A beginning in this direction has been made already by Guppy (Studies in bent and Fruits 480. 1912). BmweNs ALBA DC. Prodr. 5: oe 1836.—Coreopsis alba L Sp. Plant. 908. 1753; Chrysanthemum americanum, ciceris folio .... Herm. Par. 124. pl. 124. 1698; Bidens pilosa L. var. Antill. 7: 136. 1o11; Bidens dondiaefolia Less. fe descript et loci a Linnaea 5: 155. 1830. : This peculiar plant was treated by DeCaxpocie as one of the “species non satis notae.” I Ss n ( natis cuneatis serratis”) and ¢ citation’ of ‘habitat (“Insula St. Cmeis”) e work of HERMANN, the a Deas Batavus. Reference to this work (loc. cit.) shows a. 32 BOTANICAL GAZETTE [JULY regarding it. Recently, however, there has come to hand (in Herb. Field Mus.) a specimen (C. R. Orcutt 2886, Vera Cruz, Mexico) which agrees most minutely and strikingly with Hermann’s plate which Linnakvs cited; also another (idem 2991, Sanborn, Vera Cruz, Mexico) agreeing satisfactorily but having proliferous heads. Coming from the same locality in Mexico are other specimens which show transitions to a more elongate type of plant with some 5-parted leaves. One of these (Mueller 148, in Herb. N.Y. Bot. Gard.) is labeled Bidens dondiaefolia Less., a species likewise from Vera Cruz and the description of which it fits very well (I have not yet seen LEssiNc’s type). It is note- worthy that Lessinc called attention to the sterile shoots of this species; ‘‘rami plures steriles.” From these facts it is evident that B. dondiaefolia Less. is a synonym for B. alba (L.) DC., and that B. alba is a local species native mainly to the state of Vera Cruz, Mexico. It possibly does not occur in St. Croix, as stated by Hermann (loc. cit.). Dr. C. F. Mirispaucs, himself an authority upon the flora of St. Croix, suggests to me, and very plausibly so, that in the prepa- ration of HERMANN’s posthumous work, the name ‘Sancta Crux”’ perhaps became substituted for “Vera Crux,” and that thes the locality “‘Insula St. Crucis” finally was published. __ As to the worthiness of Bidens leucantha (L.) Willd. to rank separately from B. alba, future field observations and breeding tests are highly desirable. It seems much the safer course to retain the two names separately for the present rather than merge them as done by O. E. Scsutz (loc. cit.). The plant collected by Ghiesbreghit (no. 551) and referred be Gray (Proc. Amer. Acad. 19: 16. 1883) to B. dondiaefolia is a very | different plant and is typical B. chiapensis Brandeg. The oo specimens of B. alba so far determined’ © a we myself a at the Field ‘Museum and the New York Botanical — _ Garden (certa oo 1917] SHERFF—BIDENS 33 of Vera Cruz, Vera Cruz, Mexico, January 22, 1906; idem 97, along the shore, north of City of Vera Cruz, Vera Cruz, Mexico, January 24, 1906; C. R. Orcutt 2886, Vera Cruz, Mexico, February 16, 1910; idem 2991, Sanborn, Vera Cruz, Mexico, April 18, 1910. BIDENS HUMILIS H.B.K., Nov. Gen. et Sp. 4: 234. 1820.— Bidens consolidaefolia Tare Bull. Soc. Nat. Mosc. 24: 185. 1851. TURCZANINOW (loc. cit.) based his species Bidens consolidaefolia upon Jameson 693 from Quito. At Gray Herbarium is one sheet of specimens by JAMESON “from the vicinity of Quito and else- where,” and the specimens at the top of the sheet, while lacking a number, match precisely the description of B. consolidaefolia. It is seen from a study of many specimens of B. humilis collected in the last half century, that B. consolidaefolia is merely a slender- leaved form of B. humilis and is in no way specifically distinct. BIDENS CONNATA Muhl. ex Willd., Sp. Plant. 3: 1718. 1804. FERNALD (Rhodora 10: 197. 1908) has given an excellent discussion of this species. Commonly it occurs with simple leaves and then is the var. petiolata (Nutt.) Farwell, but occasion- ally it possesses tripartite leaves, matching MUHLENBERG’s original © description of the species proper. In July 1913 it was my good fortune to be invited to accompany Dr. FERNALD from Cam- bridge, Mass., to Winchester, Mass., and there observe the tri- _ partite leaves of the typical form, which grows in ¢ | quantity ' at that place. Tripartite leaves were prcscat on, young plants less than 3 dm. high. In the Central United States, however, ralaned tripartite leaves ‘ce ae Pe pat AT large, robust ie aax ‘specimens. FERNALD (loc. cit.) gives the range for the typical, | : = Michigan and “doubtless southward.” This range is. seen to : : eee a c. W. nae Miller, Indiana, i in an 0. E. Lonsing Jr. 1 "Rl : a Indiana, September 16, 1899; idem 1170, pages Indiana, September 22, 1900; , Roby, Indiana, § Ss 34 BOTANICAL GAZETTE [JULY BIDENS FRONDOSA L. var. ANOMALA Porter ex Fernald, Rhodora S? Or. 1903. : ' This variety is peculiar in having upwardly barbed awns, but the precise significance of their occurrence is difficult at present to judge. In a specimen of the corresponding form of B. connata Muhl., the var. anomala Farwell, I have observed numerous down- -wardly barbed awns in the same heads with upwardly barbed awns (Vasey, near Georgetown, Washington, D.C., September 23, 1888, in U.S. Nat. Herb.). Wrecanp (Bull. Torr. Bot. Club 26: 415. 1899) cites also similar material collected at Ithaca, New York. Frrnatp (Rhodora 15: 75. 1913) inclines toward regarding B. frondosa var. anomala as a geographic variety. He cites Pennsylvania, New Jersey, Delaware, also the region from Maine to Cape Breton Island for its distribution. It is interesting to note that out of many hundreds of specimens of B. frondosa that I have examined from Europe and America, there were ob- served only two instances of specimens of the var. anomala having been collected outside the range given by FERNALD. These plants, coming from Kansas and Nebraska, go further in showing the distribution to be very discontinuous. E. Hall, Kansas, in 1869 (in U.S. Nat. Herb.); P. A. Rydberg 1707, Middle Loup River, near Thedford, Nebraska, August 26, 1893 (in Herb. Gray, etc.). BIDENS ANGUSTISSIMA H.B.K., Nov. Gen. et Sp. 4: 233. 1820. The type of B. angustissima is matched very well by ScHuLtTz © Breontinus’ type of B. linifolia (both in Herb. Mus. Hist. Nat. Paris), except that the latter has only simple leaves, while the former has tripartite leaves. Katt, in publishing the description of B. linifolia (Flora 68: 203. 1885), described the heads as dis- coid. But that rays were present on at least the Paris material is shown by Scuuttz Brrontinvs’ label, in his own handwriting, _ which reads, “achs. rad. calva ... .” Furthermore, PRINGLE (no. 6924, granitic ledges at altitude a 2895 m., Cerro Ventoso ee above F Pachuca, Hidalgo, Mexico, August 18, 1898) has collected © per — : sabe aoe eye gies and these all show : > only differ- oe 1917] SHERFF—BIDENS 35 At Gray Herbarium there occurs a single sheet (Coulter 375, Mexico) with three slender but well-developed specimens; the largest one, at the left, matching the type of B. angustissima, and the other two, at the right, matching the type of B. linifolia. From these it appears safe to say that B. linifolia will be found, on future field study, to be merely a simple-leaved state of B. angustissima. ~BIDENS REFRACTA Brandeg., Zoe 1: 310. 1890.—Bidens riparia H.B.K. var. refracta O. E. Schulz, Urb. Symb. Antill. 72 132. 19xt. Scuutz (loc. cit.) regarded this species as only a variety of B. riparia H.B.K., and he differentiates the two forms on the basis of fruit chasachele But an examination of many specimens of each form shows that the only genuine difference is in the foliage. B. refracta has tripartite leaves, while B. riparia has bipinnate leaves. This difference ScHutz seems to have overlooked. Indeed, he even refers to B. refracta a plant collected by Tonduz (no. 13618, several fine specimens of which are in U.S. Nat. Herb., Herb. Brit. Mus., etc.) that is identical in foliage and other parts with the type and Bonpland cotype of B. riparia (in Herb. Mus. Hist. Nat. Paris). Of 22 collections of B. refracta studied so far, I have seen only _ one instance where the leaves were not of the tripartite kind. In this case (Jenman 5499, British Guiana, October 1889, in U.S. _ Nat. Herb.) the leaves are somewhat more divided, but still far from resembling those of true B. riparia. The probabilities are strong that B. refracta and B. riparia are entirely distinct species. BIDENs s H.B.K., Nov. Gen. et Spec. 4: 238. 1820.— Bidens tereticaulis De Prod? 5: 5938. 1836; Bidens antiguensis Coult., Bor. Gaz. 16: 100. 1891; Bidens tereticaulis DC. var. | antiguensis O. E. Schulz, Urb. Symb. Antill. 7: 142. 1911; Bidens — _ tereticaulis DC. var. sordida Greenm., Proc. Amer. Acad. 39: | 115. 1903; Bidens tereticaulis ‘De. var indivisa cere Proc. — . Bost. Soc. Nat. Hist. ae 270. 1904; Bidens Coreopsi. C. var. 36 BOTANICAL GAZETTE [JULY trisected, in having heads smaller, and in coming from a different region (“‘Differt a B. squarrosa foliis glabriusculis . . . . capitulo. minore, foliis etiam superis trisectis et patria’). But he had not seen the type material of B. squwarrosa, as is evidenced by his failure to use the abbreviation “‘v.s.’’ in connection with its descrip- tion (Joc. cit., 599). At Paris (in Herb. Mus. Hist. Nat. Paris) is still preserved KUNTH’s type of B.squarrosa. Upon the label are the words “‘ Bidens squarrosa mihi... . Caracas.”’ This is positively the specimen Kuntu had at hand in drawing up his description. It consists of a branchlet coming from a portion of a stem. The eaves of the branchlet are simple, as described by KunTH. One well preserved leaf, still attached,’ and certain similar but more fragmentary leaves, some of them broken loose, remain with the stem proper. These leaves are very important, as they establish definitely and beyond all question the identity of B. squarrosa with pubescent forms of B. tereticaulis DC., and not with B. reptans (L.) G. Don (with which it is equated by O. E. Schulz, loc. cit., 140). This will become evident on reference to pl. IX, drawn directly from the type with the utmost fidelity to all details. The presence of pubescence in this species is not of specific _ importance, a fact recognized by GREENMAN (loc. cit.) and by Scuutz (loc. cit., 142) when they treated very tomentose specimens as mere varieties of B. tereticaulis. Nor is the presence of several or even many undivided leaves of decisive value, a fact recognized by Rosrinson (loc. cit.) in treating as a variety of B. tereticaulis a specimen with all of its leaves simple. That CoutrTer (loc. cit.) treated his B. antiguensis (pl. X) as a distinct species? is easily explained by the fact that the strong superficial resemblance of _ : his first type specimen’s foliage to that of certain hispid forms of oS leucantha (L.) — led him to contrast seeds that species, . raat ey ee a ae Ce ae TATA ac At least @ Bessa omc appa” hencieat aes a Geen wee cs le Os od certain : genus Bidens, in the herbarium of Field Museum. a tema be noted that the Gu setuid inca. 2h 1917] SHERFF—BIDENS 37 from which he very properly regarded it as distinct. It is inter- esting to observe that CouLTER also noted the remarkable varia- tion in pubescence (‘‘exceedingly variable in pubescence, from glabrous to pilose-pubescent”’). B. Coreopsidis DC. var. procumbens Donn. Sm. is a form of this species. Its leaves are mainly 5-parted and are slightly narrower than in most specimens. It approaches rather closely B. reptans (L.) G. Don var. bipartita O. E. Schulz, of Porto Rico, but as a rule is quite distinct from that form. Since B. squarrosa thus is found to be so highly variable, it is thought best to present here a rather full and representative list of specimens studied: H. H. Rusby 1642, at altitude of 609 m., Guanai, Bolivia, May 1886; Mig. H. H. Smith 519, at altitude of 609 m., Jiracasaca, Santa Marta, Colombia, October 1898-1901; C. Hoffmann 383, Valley of the Rio Legardo, Costa Rica; Ad. Tonduz Sooke at altitude of 1800 m., forests of the Mala Via at Copey, Costa Rica, April 1898; idem 7265, banks of the Rio Maria Aguilar near San Jose, Costa Rica, December 29, 1892; idem 13600, in thickets, Nicoya, Costa Rica, January 1900; idem 7058, at altitude of rroo m., San Francisco de Guadalupe, Prov. San Jose, Costa Rica, January 1896; idem 7248, in thickets 18, 1892; C. F. Baker 2121, Dept. Leon, Nicaragua, January 17, 1903; idem _ 2214, Masaya, Dept. Masaya, Nicaragua, January 27, 1903; H. Pittier 1838, at altitude of 600 m., in hedges around Copan, Honduras, January 9, 1907; — Luis V. Velasco 8873, San Salvador, Salvador, December 1905; W. A. Keller- man 5341, El Rancho, Sierro de las Minas Mountains, Baja Vera Paz, Gente: mala, January 6, 1906; idem 5351, at altitude of 1205 m., Moran, Guatemala, February 11, 1905; idem 6118, Volcano Acatenango, Chimalte 2 nango, Guatemala, February 8, 1907; idem 8035, at altitude of 1067 m., El. Rancho, Sierra de las Minas Mountains, pais in toe temele, Jeetey 1908; Maxon and Hay 3162, at altit de m., _ Alta Vera Paz, Guatemala, January 4 1905; JZ ; altitude of 1778 m., Antigua, Sacatepequez, Guat an D and Lux 4193, at altitude of 1956 m., Buena Vis Pt anta [ seh acer Ww. D. ASE at ee 79 38 BOTANICAL GAZETTE [JULY February 12, 1905; Enrique Th. Heyde 666, Guatemala, in 1892; Berlandier 730 and 2150, Tantoyuca, Vera Cruz, Mexico, December 1830; idem 2148, Mexico; Botteri 489, Orizaba, Vera Cruz, Mexico; Bourgeau 1560, Valley of Cordoba, Vera Cruz, Mexico, October 12, 1865; idem 3093, Orizaba, Mexico, October 3, 1866; C. Conzatti 122, at altitude of 1200 m., Mountains of Oaxaca, Mexico, September 20, 1895; idem 1581, at altitude of 1800 m., Cerro San Antonio, Oaxaca, Mexico, October 28, 1906; idem 2269, at altitude of 2000 m., Cerro San Felipe (Distr. del Centro), Oaxaca, Mexico, October 18, eS Conzatti and Gonzalez 1133, at altitude of 850 m., Cordoba, Vera Cruz, Mexico, December 1900; E. A. Goldman 30, at altitude of 244 m., near Metlaltoyuca, Puebla, Mexico, January 27, 1893; idem 493, Apazote, Campeche, Mexico, ember 28, 1900; E. W. D. Holway 3667, Oaxaca, Mexico, October 18, 1899; E. Langlassé 689, at altitude of 300 m., southern Mexico, December 2, 1898; E. W. Nelson 1508, at altitude of 1585-2075 m., Valley of Oaxaca, Oaxaca, Mexico, October 2, 1894; idem 1824, at altitude of Bue ee m., 9.6 km. above Dominguillo, Oaxaca, Mexico, October 30, 1894; idem 3410, near Yajalon, Chiapas, Mexico, November 21, nen . R. Orcutt 3031, Sanborn, Vera Cruz, Mexico, April 18, 1910; C. A. Pur 33, Zacuapan, Vera Cruz, Mexico, October 1909; Charles L. Smith 298 say oS at altitude of 1955-2135 m., Monte Alban, near City of Oaxaca, Oaxaca, Mexico, October 1894; idem <7, Coatzacoalcos, Vera Cruz, Mexico, February 6, 1895; Lucius C. Smith, at altitude of sha5 m., Rancho de Calderon, Oaxaca, Mexico, September 10, 1894. : Bidens Brandegeei, sp. nov.—Herba annua, erecta (nisi infra plus minusve arcuata), 3-5 dm. alta, maximam partem albido- hispida. Caulis quadrangulatus, striatus, ramis tenuibus ramosus. Folia opposita, petiolata, petiolo adjecto 1-8 cm. longa, pinnata aut bipinnata, supra minus albido-hispida; foliolis 3-5, ovatis (aut ovato-lanceolatis) serratisque et non dissimilibus iis B. leucanthae _(L.) Willd., aut pinnati partitis, lobulis aut dentibus indurato- apiculatis; petiolis o.2-2.5 cm. longis, basi connatis. Capitula _ pauca, terminalia, ligulata, tenuiter pedunculata, pedunculis _ monocephalicis, 3-8 cm. longis. Involucri squamis subaequalibus _ duplici serie dispositis; exterioribus (circ. 8) linearibus, 1-nervatis, / apiculatis, albido-ciliatis st-hispidis, 4-5 mm. longis; interioribus — 1917] SHERFF—BIDENS 39 T. S. Brandegee, in vicinity of San Luis Tultitlanapa, Puebla, near the Oaxaca boundary line, Mexico, in 1908 (first type sheet in Herb. Univ. Cal., herb. no. 134267, and second type sheet, dated July, also in Herb. Univ. Cal., herb. no. 134268); C. A. Purpus 4429 (in vicinity of San Luis Tultitlanapa, Puebla), Oaxaca, Mexico, August 1 species having at times all the ‘lentes tripartite and then deceivingly like B. leucantha (L.) Willd. except as to achenes. The description is drawn mainly from the two flowering specimens on the first type sheet, but the achene characters are described from the single fruiting head present on the writings ae exteyled our knowledge of this genus to a considerable extent. Recently, Dr. Smney F. BLAKE has sent from Gray Herbarium a specimen of Bidens that appeared to him as allied with Bidens rubifolia H.B.K., but none the less new. The plant was collected by Hotway in Guatemala early in the present year, and is described by him as “climbing over trees 40-50 — and then dropping down nearly to the ground.” Its heads, i asure about 6 cm. in diameter. From B. rubifolia it may easily be recognized in behead specimens by its large involucre and the unique char- acters of the involucral bracts. + detailed description is peeento here: Gelcie Visine Shcee and Hiake: sp. nov.—Herba scandens, -caule demum 20-30 m. longo, ascendente (ex Hotwayo) in altitu- | dinem 12-15 m.; ramis tetragonis, glabris, striatis. Folia opposita, petiolata, petiolo adjecto 6-18 cm. longa, tripartita aut summa indi- visa, ciliata, supra glabrata (nisi ad venas), infra plus minusve piloso-hispida, serrata; foliolis lateralibus ovatis aut ovato-lanceo- oe latis, terminali ovato-l: dla aut | 1. to. ‘Petioli I. - 5 4em. 2 Q 40 BOTANICAL GAZETTE [JULY diaphanis. Achaenia linearia, subplana, nigra, ciliata, ad facies sparsim hispida, 1.3 cm. longa, ad apicem nonnullis erectis setis coronata, biaristata aristis retrorsum hamosis et divaricantibus. E.W. D. Holway 816, Quezaltenango, Guatemala, January 31, 1917 (type in Herb. Gray). BIDENS SAMBUCIFOLIA Cav. Icon et Descript. 3:15. pl. 229. 1794; Bidens alamosana Rose, Contrib. U.S. Nat. Herb. 1:104 pl. 6. 1891. A comparison of the type illustration of Bidens alamosana with that of B. sambucifolia reveals a remarkable similarity. Further- more, the descriptions of the two species are very close and differ materially only in that the ligules of B. sambucifolia are described as scarlet; those of B. alamosana are yellow or orange-yellow. CAVANILLES’ description was based upon material from the Royal Garden at Madrid and which was stated by him to have come originally from Peru and Mexico. It may well be that his citation of Peru was entirely erroneous, as I have never been able to find a specimen from elsewhere than Mexico. An examination a numerous specimens collected in Mexico shows the ligules to be : y yellow or orange-yellow, but in certain rare cases the ligules nae the dried specimens) have a color so reddish as to explain quite plausibly how Cavanilles was led to call them scarlet (“corolla to the en Gaunns (4) found di-potassium phosphate neutral - in its effects upon the burn. = sk consideration of the reason, for the aE in of : the potassium salts of organic acids has led to several theories. oe : SCHLOSING (15) attributes their favorable action to the fact t that os : and y Se $ mass. soa ee (2) 44 BOTANICAL GAZETTE [yoLy oxygen carrier. MAvYER (10) also attributes the beneficial effects of the alkali salts to the fact that they are easily reduced. BArTH © (1) suggests that the salts may have a beneficial action by raising the temperature of the leaf; he also attributes the harmful effect of the chlorides to the fact that they fuse and coat over the material, thereby preventing complete combustion. Object The object of this work is to study the effects of various salts closely related to the salts of potassium with a view to obtaining some light upon the conflicting theories. It has been suggested that the effect of the various salts upon the colloidal state of the material of the leaf may bear some relation to the problem. It was thought that probably potassium possesses some peculiar _ chemical properties which may account for its action. ses of salts upon combustion of tobacco METHOD ‘The method of experimentation consisted of treating leaves and filter paper with various salts and noting their effect upon the __ fire-holding capacity. The samples of tobacco used in this work a Jeete OF 8 sine brain, of a tear Hiden pe oe tobacco grown in oe under definite fertilizer treatments. The leaves y had been well sweated. In all cases the solutions of Ej rapoadiess were 28.9 per cent normal. In order to see __whether the effect of the salts was upon the colloidal state of the oe Rioiee by a treatment with o.2 no ue materials of the leaf, some of the leaves were rendered acid by _ treatment with o.5 normal acetic acid, and others were rendered : 1917] KRAYBILL—ALKALI SALTS 45 expected, due to variations in different leaves, the results were not always consistent in some cases where the comparative differ- ences were small, but in each case a number of tests were carried out upon a number of different leaves until the average results were considered reliable for the purpose of comparing the effects of the various salts. : DATA Because of the similarity in chemical behavior of the alkalies caesium, rubidium, potassium, sodium, and lithium, it was thought that a comparison of the effects of their salts upon the fire- TABLE I LEAVES FROM PLATS FERTILIZED WITH MANURE ONLY Average number Average number] of seconds in- Salt treatment Other treatment ‘Number of tests} of seconds | creases fire- 50 7 60 a0. 40 Pee 60 18 oU§ Se 19 we 10 59 45 ee 44 35 fe. 18 Io 9. a) aS ae 9° eee a ae oe (68 Se = 7 oe 46 BOTANICAL GAZETTE [yULY a minor factor. According to H6BER (5), the relative effectiveness of the alkalies i in precipitating colloids in an acid medium is as follows: lithium>sodium>potassium>rubidium>caesium. In an alkaline medium the order is as follows: caesium >rubidium > potassium >sodium>lithium. In the cases where lithium is more 1 ae TABLE II LEAVES FROM PLATS FERTILIZED WITH POTASSIUM CHLORIDE Average number Average number) of seconds in- Salt treatment Other treatment Number of tests} of creases holds fire holding ca- pacity pS a 2s as o.2/N NaOH 60 54 49 Nats. 2.56... . 60 2r 14 oO eS eee . . 60 16 10 RANK. o.5/N acetic acid 20 27 24 NaCO,. . 2.25... -5 . 20 8 5 BAAR. ee ee 20 9 6 Cs,CO;. Nothing 20 61 57 RAMS. oo 30 40 36 ENN. oa oe. e: 20 48 44 TABLE III _ LEAVES FROM PLATS FERTILIZED WITH MANURE ALONE ' 1917] minor importance. KRAYBILL—ALKALI SALTS 47 It seems very evident that of all the alkali carbonates only those of caesium, rubidium, and potassium mate- rially aid the fire-holding capacity. Table III shows that of the oxalates of potassium, lithium, and sodium, only the oxalate of potassium is effective in increasing TABLE IV. LEAVES FROM PLATS FERTILIZED WITH MANURE ALONE Average nu Average number! of seconds in- Salt treatment Other treatment Number of tests} of seconds creases pacity Potassium Aisi .-.| 0.2/N NaOH 30 29 13 Sodium citrate. ..... . 20 1§ 4 pteocheres on eos oh. _ 20 16 6 Potassium citrate....| o.5/N acetic acid 20 30° 19 Sodium citrate. ..... . 20 18 I Lithium citrate......| . 20 19 - Potassium citrate Nothing 20 24 18 Sodium citrate. ..... ” 20 10 4 Lithium citrate . 20 Ir 5 TABLE V LEAVES FROM PLATS FERTILIZED WITH POTASSIUM CHLORIDE ie! j ats 7 Ny } , : Hebe «Se . : = Potassium citrate... 0.2/N NaOH 50 28 Sodium citrate...... ae 50 Ir Lithium citrate......) Pe ge we ‘Potassium citrate....| o.5/N acetic acid 20 37 Sodium citr: eels Seog 20 10. Lithium citrate. . . 20 > ve - the fire-holding cz capacity. ae again in the cases sates i lit rit 2 Ss more effective than sodium i in the ——* ofc colloids, 48 BOTANICAL GAZETTE [JULY Table VI shows a comparison of the results of a number of potassium salts. All of the potassium salts are very effective in promoting the fire-holding capacity, with the exception of the chloride, acid sulphate, and mono-potassium phosphate, which TABLE VI LEAVES FROM PLATS FERTILIZED WITH MANURE ALONE Average (Average —— | Number of | Bumber.of | of seconds i teste ehissaeay Sage ee Se ee Oe ee § | he UnPawwHann | | x09) KRAYBILL—ALKALI SALTS 49 are either nearly neutral or exert a harmful effect. It is quite evident that none of the sodium salts exert the marked beneficial effects which some of the potassium salts exert. Effect of salts upon combustion of lump sugar The effect of various salts of the alkalies upon the combustion of different kinds of paper and lump sugar was also studied; although, as one would expect, due to the dissimilarity of materials, the results in these cases were not always parallel with those upon tobacco. The results with lump sugar are particularly interesting. In each case a small portion of the salt was placed upon the lump of sugar and then an attempt was made to burn the sugar by touching it to a gas flame. The results obtained are indicated in table VIII. Discussion _ SCHLOSING (15) attributed the favorable action a the organic salts of potassium to the fact that they swell up and yield a porous mass. NESSLER (12) combated this idea and showed that other salts of potassium which do not swell so much when heated also have a favorable action in promoting the fire-holding capacity of tobacco. GARNER showed that the carbonates of potassium are ve just as effective as the organic salts. From resnabhee a - _ These results confirm the conclusions « 2 stnasosypaancice indicate that the good effects of the potassium salts of organic a acids cannot be attributed to the fact that — swell and _ oS 5° BOTANICAL GAZETTE {JULY represents their increasing ease of reduction in solution. If we assume that this represents the order of the ease of reduction of the TABLE VIII EFFECT OF SALTS UPON THE COMBUSTION OF LUMP SUGAR Salt Effect a ak 8 PM Ee eee Lump of sugar burned with flame; sugar coaled Rb,CO;. een es “ “ & “ “ “ “ “ 8 pS OAR ee SS - : . - . Na.CO, a ee “ce ac “ee ““c “ce “ce “é “ce : Live... ee “ “ “ “ “ “ “ Baw). o.oo ake of sugar burned slightly; _ coaled slightly KarO,.. ....2.5. Lump of sugar burned; sugar coal Bre. ce. Lump of sugar baraed teh ange coaled slightly Mahe ck eee Lump of sugar b | Se ee ae 9 4 8 pe ,..Lump of eisptcius ae sack, sugar coaled Potassium acetate ..Lump og sugar burned with flame; sugar coaled Potassium citrate. oe “ “ “« “ “a “ “ Potassium oxalate ...* “* * . . ie * « Pomme. © © © © & & * 8 ii tt 2 * . iithua wales... *. * * 5 * “ “ “ Lihtuncinie..... * © *: . . é, i “ 3 UES RRS i ec aie ere ~ home of saat boned 958 Fame puget coaled _ Sodium oxalate... .. oy een eS eS "daa haga wiinad Vial sore did not coal 7 iy Sugar melted; did not burn with flame; did not coal Na,SO,. .. panic d slightly; sugar — ea ee Sugar melted; did not burn with flame; did not coal P A Pe peo) ane meee ae Dae a oo BaCO,.. L. | 1917] KRAYBILL—ALKALI SALTS 51 alkali carbonates, it would be difficult to explain by NEssLEer’s theory why lithium and sodium carbonates are not effective, and caesium, rubidium, and potassium carbonates are effective. GARNER (4) suggests that the carbonate might act favorably by alternately giving up and taking on carbon dioxide. We have seen that caesium, rubidium, and potassium carbonates are very much more effective than the carbonates of sodium and lithium. At joo C. the order of the alkali carbonates according to their increasing ease of dissociation is as follows: potassium, rubidium, sodium, caesium, and lithium. Lithium carbonate is dissociated into carbon dioxide and lithium oxide to a much greater degree at 7oo° C. than any of the other carbonates (9). If potassium carbonate acts favorably by alternately giving off and taking up carbon dioxide, it is difficult to see why lithium carbonate should not be even more effective. It seems, therefore, that this theory will not explain the beneficial action of the caesium, potassium, and rubidium carbonates. From table VIII we see that all of the salts which were effective in increasing the fire-holding capacity of tobacco will cause the lump of sugar to burn with a flame when ignited by means of a gas burner. Some of the salts which were only slightly effective in increasing the fire-holding aia d of + AED, such as nthe the combustion of sugar with the production. of a flame. ‘Here again caesium, potassium, and rubidium cecuutes are particu- — larly active. Barra (1) has suggested that the salts present in — the leaf may aid in the combustion by raising the temperature of the leaf, the effect being somewhat analogous to the effectof salts upon raising the boiling point of water. As shown i in table : VIII, such substances as metallic fili | ind bonized sugar when used in larger pial also ar a. : eee et ee to burn. From these eaten > sugar, it would seem as though their effect in raising — 52 BOTANICAL GAZETTE [JULY marked effect in promoting the combustion of tobacco. SLIGH and KRrayBILL (16) have determined the temperatures of burning cigars and have found some evidence which suggests that the moisture content as well as the composition of the cigar has an effect upon the burning temperature. It is planned to study this problem further with the object of determining the extent to which this hypothesis may be applied. BartTH (1) considers the harmful effect of chlorides to be due to the fact that they fuse and coat over the material, thereby preventing complete combustion. SLicH and KRavyBItt (16) found the temperature in the cigar varying from 813° C. to 925° C. during a puff, and from 584° C. to 803° C. at stationary temperatures between the puffs. It is doubtful whether the temperature of the burning strip of a leaf of tobacco would be as high as these stationary temperatures of the cigar. The temperature of the leaf then would not be high enough to fuse pure sodium chloride or pure potassium chloride. It would seem then as though the theory of BARTH would not account for the harmful effect of the chlorides. An objection might be raised from the standpoint , that we have in the leaf mixtures of salts, and that their fusing ‘points would be lower than that of the pure salts. The fusing point of sodium chloride is about 820° C., and that of rubidium : carbonate is 837° C. (9). Tt would he Gilet te anileeatnad why © = one salt should harm the burn by fusing and the other should - ee the ‘same tem- perature. An attempt was ‘ead: to tabulate and compare the chemical and physical properti ee eee celia eh Ue hope of merci a ae the melting points, specific heats, weed ok ‘vaporization, ot dissociation | rbon A very careful com- 1917] KRAYBILL—ALKALI SALTS 53 not be due in part to the alkalinity of the salts in solution. Such . an explanation, however, would not account for the behavior of the sodium and lithium carbonates. Extremely small amounts of caesium, potassium, or rubidium carbonates greatly increase the fire-holding capacity of the tobacco. A 2 per cent solution of potassium carbonate applied by means of an atomizer to the leaf was sufficient to produce the effect. Upon examining the ash left after the combustion, the potassium was found as the carbonate, that is, in the same form in which it was present before the combustion. It is possible, therefore, that certain salts, such as the carbonate, phosphate, and sulphate of potassium, and the carbonates of rubidium and caesium, act in a catalytic manner to promote the combustion of the tobacco leaf. In the combustion of lump sugar other salts are also effective, but the carbonates of caesium, potassium, and rubidium are more effective. Here the effect of the salts in raising the temperature may be important. According to this al . raecdim chiinnkle. ceramann educa bonate, rubidium carbonate, tri-potassium phosphate, di-potassi phosphate, and potassium sulphate have a catalytic action favor- _ ing the combustion of the tobacco leaf. The salts of sodium _ and lithium, potassium chloride, mono-potassium phosphate, and — _ acid potassium sulphate do not have this catalytic action. The harmful effects of the chlorides seem a ane ele eameien Ta 5 ye ere pe ra) 1. eu eueacs - Vs SAA when various organic materials, srpepertial ay and: sugar - treated with the - are a to te ur | ee Ner (zx) has studied the e 1 the oxidation of _ x a oS in a solution | at low ek xidation of 1 nical acti retaning sconce - 54 BOTANICAL GAZETTE [JULY Summary 1. The alkali carbonates of caesium, rubidium, ana potassium have a definite marked effect in promoting the fire-holding capacity of tobacco, which sodium and lithium carbonates do not exhibit, the order of effectiveness being as follows: caesium, rubidium, potassium. 2. Of the oxalates tried, only potassium is effective. In the case of the carbonates and the oxalates in an alkaline medium, where lithium is more effective than sodium in the precipitation of colloids, it is slightly more effective also in promoting the fire- Iding capacity. In the case of the citrates there is no such relation and, in the case of the carbonates, potassium, rubidium, and caesium do not behave in this manner. It is doubtful, there- fore, whether the effect of the salts upon the colloidal state of the tobacco leaf is of any significance. 3. Only potassium citrate is effective in promoting the burn. The citrates of sodium and lithium are nearly neutral in their effect. 4. The organic salts of potassium, potassium carbonate, tri- potassium phosphate, di-potassium phosphate, and potassium sul- phate improve the fire-holding capacity; while potassium chloride, acid potassium sulphate, and mono-potassium gee ears are inju- rious to the burn. | Sodium 1 eh, eee a . yy : 2 4 at 7S holding y slightly, — while all of the other sodium salts a are either neutral or injurious to the burn. ee The data obtained do not confirm the idea that the reduction _of the potassium salts will account for their favorable action. 7. Data are given which indicate that the harmful action of : chases is nde $6 the fark Cat they fae ee oo Data are given which indicate oats the alternately giving ___ offand taking up of carbon di effects of potassium carbonate. ae a bes of s € Si l oni : - Bs eric of the salts i in ‘raising the fe oa 1917] KRAYBILL—ALKALI SALTS 55 11. It seems probable that caesium, potassium, and rubidium in the form of certain salts, such as the carbonates, sulphates, and phosphates, have a specific catalytic action in the combustion, and that the chlorides have a negative catalytic action. It is planned to study the rate of decomposition of various organic salts of the alkalies, and also the decomposition products of various organic substances treated with salts of the alkalies, when sub- jected to temperatures which are attained in the burning cigar. Acknowledgments are due to Dr. Wm. Crocker for many helpful suggestions and criticisms, and to Mr. Orro OLson of the United States Department of Agriculture for the = of tobacco used in this work. UNIVERSITY OF CHICAGO LITERATURE CITED 1. BARTH, Max, Untersuchungen von im Elsass ~ gesozenen Tabaken und einige Beziehungen zwischen der Qualitat des Tabaks und seiner Zusam- . Landw. Ver. Stat. 7 ua he ok, 2. BEHRENS, J., Weitere Beitrige zur Ker Tabakpflenze. Landw. Ver. Stat. 43: he 1895- 3- CARPENTER, F. B., Types of tobacco and their analyses North Carolina State Agric. Exper. Bull. no. 122. 1895. 4- GARNER, W. W., Th Se are OR Mae ee qualities of tobacco. Baloo. BaP nd US Dept. Agric. 5. Hoser, M. R., Ph Gewebe. Leip und Berlin. 1914. i . oe 6. Jenkins, E. H., Experi ir with different fertilizers. Ann. Rep. Conn. State Agric. Poy Sta. rugs 1895. 7. Kisstinc, RicHarp, Die Chemie des Tabaks. Chem. Zeit. 8: 68. 1884. 7 ie cc ee es aie NOTES ON NEW OR RARE SPECIES OF RAVENELIA W. H. Lone While on recent field work in Texas, the writer collected several very interesting species of Ravenelia. Some of them are unde- scribed, while others have heretofore been known only from their type collections. Several of them are Mexican, while one is a South American species. Ravenelia hoffmanseggiae, sp. nov. O. Pycnia unknown. Il. Uredinia amphigenous, scattered, orbicular to irregularly oval, liver brown,’ subepidermal, ruptured epidermis prominent; paraphyses none; urediniospores obovate, ellipsoid to subglobose, 16-25 by 25-30, average for 10 spores 19.7 by 26.7, walls — thin, 1-1.5 w, uniform in thickness and concolorous, capucine buff in color, sparsely and minutely echinulate when dry but appearing as if smooth when wet; germ pores 8, situated in two irregular — rows of 4 each, one row subequatorial, the other near apex of spore, ee - Ii Telia unknown. se On Cassiaceae. Ty Nected oa Hoffmoniers! taps at Del 1 Rio, : ‘Texas, November 6, ion 6, by W. Doce 6082)? This isthe ist cole. tion « fmanseggia is widely distributed throughout those “regions where species of Rasenelia flourish 58 BOTANICAL GAZETTE [JULY urediniospores obovate, obovate-elliptical to subpyriform, 15-18 _ by 25-37 », average for 20 spores 16.9 by 31.7 u, walls ochraceous- tawny, concolorous, thick, 2.5-3.5 4, apex but slightly if at all thickened, echinulate; germ pores prominent, 6 in equator. III. Telia amphigenous, usually epiphyllous, sparse, scattered, small, o.1-0.5 mm. across, bullate to elliptical, subcuticular, blackish-brown, tardily naked, ruptured cuticle very conspicuous; paraphyses none; teliospore heads chestnut-brown, subglobose, 40-60 p in diameter, average for 20 heads 50.5 u, 2-4 spores across, 5-10 spores to each head, 4-8 marginal, o-3 inner spores, usual number of spores per head 7-8, each spore bearing 3-6 short hydline tubercles 3-5 4 long; cysts few, 4-8, as many as the marginal spores, subglobose, subpendant around pedicel, not cohering, easily. swelling and bursting in water; pedicel hyaline, short, —— compound. On Mimosaceae. Type collected on Siderocarpos flexicaulis 6 ‘alien from Brownsville, near Tandy’s Switch, Texas, November 11, 1916, by W. H. Long _ (no. 6174). This Ravenelia is very abundant on this heat 4 in the Texas ebony jungles in the immediate vicinity of Brownsville. It is probably common wherever its host is found i in sufficient quantity to form thickets. Ravenelia prosopiis, sp. nov. oO. ‘IL, Uredinia sparse in material examined, small, amphigenous, ‘ead ealylow, often in a circle around a central sorus, 0. 5—- -_y.9mm. across, narrowly elliptical to , subepidermal, long | covered by the epidermis, ruptured ad very prominent; ___ urediniospores oval to subpyriform, 13-20 by 24-41 p, strontium : lla eae for 40 spores, 16. one S had walls: I. 5-2 u thick, oe 4-6 in equ ¢ ua tor; paraphyses abu aed dan t, of two ape, ia deal pane : a capitate, the ae Saane clavate, ina Sense bane around the i : 1917] LONG—RAVENELIA 59 . elliptical to oval, subepidermal, early naked, ruptured epidermis very prominent; teliospore-heads tawny, depressed hemispherical, often concave at top, 75-118 uw, average for 40 heads 94 p, 6-10 spores across, 20-28 marginal spores, 16-40 inner spores, usual number for head 46-54 spores in all; heads papillate, with one, rarely two, papillae to each spore, papillae ranging from mere tubercles near top of head to blunt papillae 4-7 yw long around margin, top of heads often free from papillae, many heads with only a few tubercles on entire head, papillae light brown; paraphyses very abundant in a dense circle around the telia, also scattered throughout the sorus, similar to those found in the ure- dinia, often sori occur which are composed mainly of paraphyses; cysts numerous, pendant in 2 or 3 rows around the pedicel, sub- globose, about as many as marginal spores, easily swelling and bursting in water; pedicel coats etoanit, deciduous, —_ to faintly fulvous, short. On Mimosaceae. Type collected on Prosopis Jaitors at Denton, tenis, October 10, 1907, by W. H. Long (no. 2013); a same host and in same locality in 1908 by Long (no. 4870). Ack the type material of this Ravenelia was issued in Fungi ncmaseane Ee exraccoienn, no. 2681, _ as Ravenelia arizonica Ellis and Ev. — Ravenelia prosopidis is closely related to R. arisonica, but differs from this zonica. "alk peciee wal postal bs lens the range of its host. It is sometimes associat Neoravenelia avenelia holwayi, at least some telia were found which conta Lo : spores with be iy eth wie her end alee oc cota oe 5 : os (nos. 6145 and 6148). 60 BOTANICAL GAZETTE [JULY brooms, often densely confluent on both sides of the pods over areas I-5cm. across, individual uredinia on pods elliptical to irregularly oval, o.2-0.6 mm. across, verona brown to tawny-olive in color, uredinia on leaves amphigenous, elliptical to irregularly oval, primary uredinia often encircling pycnia; urediniospores obovate-oblong to linear-oblong, on pods 10-17 by 27-45 mu, average for 20 spores 13 by 31 u, on leaves urediniospores are 10-14 by 27-38, average for 20 spores 13 by 33 p, average for both sets of spores 13 by 32u; walls 1-1.5y thick, slightly thicker above (about 3), prominently but sparsely echinulate, spinules very sparse on upper third of spore, upper third golden brown to wine color, remainder of spore paler to hyaline, germ pores 8, in 2 rows of 4 each, upper row at boundary of colored and hyaline part of spore, lower row about the same distance below the equator; paraphyses abundant, intermixed with the urediniospores, clavate to clavate-capitate, 35-50 u long, average length for 10, 44.0n, heads 9-13 uw, average for 10 heads toy, apex of head thickened about 3 », pale fulvous, stipe usually thin-walled, hyaline. III. Telia amphigenous, often abundant on all parts of badly infected leaves, scattered, subcuticular, blackish, shining, o.2- 1.2mm. across, irregularly oval, ruptured cuticle noticeable; _ teliospore heads blackish, 63-100 uw, average for 30 heads 78 un, 5-7 cells across, 14-30 spores in each head, 8-14 marginal spores and 6-15 inner ones, verrucose, each spore bearing 3-10 colorless warts about 2 u tall by 3 » broad; paraphyses present and similar to those in uredinia; cysts of same number as marginal spores, flattened, appressed beneath head, extending from periphery to _ pedicel, in one row, united laterally, ovoid to oblong-ovate, slow to burst in water; pedicel short, colorless, compound, deciduous. : DISTRIBUTION.—TEXAS: On Acacio roemeriana, San Marcos (type local- as ity), poy in . November TOTS (nos. 5494 and 5498 type), i in May 1916 (nos. 6909, 6019, 6020, and 6065); San Antonio, Long, in May 1916 (nos. 5610, — 5611, 5612, 5614, and 5615), 08} in | November aie es. 6155 and 6159); Uvalde, Heald and Wolf, : deride ——! —_ merianae ww tte lee wt cacia iit emerian: pe 1917] LONG—RAVENELIA 61 visited the type locality of this rust at San Marcos and found an abundance of uredinia, especially on the pods. Some uredinia as well as pycnia were also found on the leaves. Even at that early date telia were developing and the uredinia on the leaves were disappearing. The uredinia which were so abun- dant on the pods in May weathered and disappeared so that none were found on the pods in November of the same year. The writer has seen several thousand trees of Acacia roemeriana infected with this Ravenelia in various places in Texas, and only two trees of this entire number showed any evidence of witches’ brooms. One tree was found at San Antonio and the other at Uvalde, Texas. There were some 1o-15 witches’ brooms on each of these two trees. Apparently the germination of the telio- spores of this rust occurs when the pods are young and easily infected and yet not at the right season to infect the young branches and cause witches’ brooms. This rust is closely related to Ravenelia versatilis (Peck) Dietel, a vie noted in a previous article’ by the writer. TableIg more — salient characters of each of these two species of Ravenelia. From this table the main differences between the two species are easily seen Ravenelia roemerianae has been collected by the crits a several places in Texas and probably occurs wherever the host is present. The rust was exceedingly abundant in the vicinity of Uvalde, Texas, in November 1916. Every tree of Acacia roemeriana examined by the writer in the mesquite Presepis juliflora)-catclaw (Acacia roemeriana) flats was heavily infected; in ‘leaf on most of the trees was practically covered with the blackish telia of this rust. RAVENELIA MESILLANA Ellis and Barth. Bull. Torr. Bot. Club_ 251508. 1898 * : (Ravenelia lensiona Sydow, Hedwigia Beibl. ak Toor). O. Pycnia, appearing before the uredinia, sparse, amphige- nous, in circinating, crowded, orbicular groups | : subcuticular, Brussels brown, ——- hemispherical, 40-60 iat a wR geceests 7 . Uredinia am tawny, oval to elliptical, °. s-1. chon sinty Juve aay ket pe ao _ verulent, subcuticular, ruptured cuticle very noticeable; uredinio- - Spores oval to subglobose, 15-22 by 20-26 u, ee a - SF 19 J 23 oe thick, oo ! ¥ aBeiont ‘s 06-55 BOTANICAL GAZETTE ISOINLIIA SPBIY yeursivur ‘nf gl advaaar ‘Wf oo1-£9 spray BHT, 6 1917] - LONG—RAVENELIA 63 the spores, colorless, clavate to subcapitate, 5-14 by 35-62 y, average for 20, 9.6 by 45 u, apex of head thin-walled, base of head very thick-walled, stipe usually solid. III. Telia amphigenous, scattered, o.5—1.0 mm. across, often confluent over areas 3-4 mm. in diameter, brownish-black, elliptical to irregularly oval, subcuticular, ruptured cuticle very conspicuous; teliospore heads dark chestnut-brown, hemispherical, smooth or an occasional head with a few scattered, short (2-3 u), hyaline, tubercles, especially on the marginal spores, 5-9 cells across, 60- gO w, average for 20 heads 74 uw, 10-20 marginal spores, 8-24 inner spores, usual number per head 24-32; paraphyses present but very few and similar in every way to those found in the uredinia; cysts hyaline, in 2-3 rows around the pedicel, many, not coherent with each other, slow to burst in water, subpendant; penis colorless, compound, short, deciduous. This description of the rust was drawn from + Distripution.—New Mexico: On Cassia bauhinioides, “Mesilla Park, Wooton, in October 1895, ex. Herb. N.Y. Bot. Garden (no. 5021 Long) and ex. Herb. A. and M. College of N. Mex. (no. 5022 Long); Wooton in October i. North American Fungi, Herb. of ELam BaRTHOLOMEW (part of ty = re See August 1901 and October 1915 faa 1019 and tan: Llano, ne ead Wolf, 1909 (no. 1751 Herb. Path. and ; Myc. Investigat., Plant Disease Sur- oe and vey); Marble Falls, Carsner and Studhalter, May 1912 (no. 4333 Herb. Univ. Texas); Meridian, Long, June 1916 (no. 6056); San Antonio, Long, May and — November 1916 (nos. 5616 and ots San Marcos, i November 1915, and May 1916 (nos. 5468 and 6034). This &. Cacsia ba SEES ee at Mesilla rk | New Mexico, in 1895 and aanin in 1897 “ee Wooton. It was described as a a ae lected in 1897. Tt has been reported on a In 1900, ~ writer sent $ . Austin, T: 64 BOTANICAL GAZETTE [JULY while R. longiana had a few hyaline ones. The writer has material from the type collections of both of these species, and a careful examination of this material shows that not only do both species have paraphyses, but that the paraphyses are identical in every respect and are present in the telia of the type material of both R. mesillana and R. longiana. A careful study of the other salient characters of these rusts has convinced the writer that they are identical in every respect and therefore should be considered as only one species In recent field work in Texas, the writer collected the pycnidial stage on Cassia roemeriana of what has heretofore been known as Ravenelia longiana. RAVENELIA SILIQUAE Long O. Pycnia unknown. II. Uredinia hypophyllous and caulicolous, on the leaves scattered, elliptical, o. 5—1.o mm. across, pulverulent, subcuticular, early naked, sudan brown, ruptured cuticle not prominent, uredinia on the woody twigs and branches perennial, very inconspicuous, elliptical, o.5-5 mm. long by o.5-2 mm. broad; urediniospores obovate, elliptical to rarely oblong, on the leaves 13-17 by 20-27 u, average for 10 spores 14.4 by 21, urediniospores on branches 11-16 by 17-27 m, average for 20 spores 13.4 by 22.5 uw, uredinio- spores on both leaves and branches buff yellow; walls 1.5-2.5 4 thick, concolorous, not thickened at apex, densely and strongly ver- -Tucose, germ pores 8, in two transverse zones of four each, equidis- tant from the equator; paraphyses abundant, intermixed with the spores, clavate to subcapitate, often curved, 7-10 by 50-67 yn, average for 10 paraphyses 9.5 by 62u, heads pale fulvous to hyaline, stipe slender, usually solid, hyaline, paraphyses in sori on woody branches few, 6-11 by 25-49 uw, average for 20 paraphyses 8.3 by 38u. : — ML tela unknown. a On Mimosaceae: Distributed ; as follows: Tern, on ae ine San Antonio, Long, November 1916 (no. 6153); W. H. Mercer, February 1917 a (no. 6263); _— on Acacia farnesiana, Etla, Oaxaca, Holway, October 1899, no. 3841 of | Holway (type); Hawaii, on jrempaies farnesiana, Honolulu, ; o Hora ze Lyon, jou. 1013, ae 164, 4, SyDo’ = 3 aston he pd of thos fom Haw ares eye ith the : « 1917] LONG—RAVENELIA 65 on the pods of Acacia farnesiana from Mexico, the rust has been collected in Texas on the leaves and woody branches of this host and in Hawaii on the It was probably introduced into Hawaii on nursery stock which con- tained infected woody branches. Apparently Ravenelia siliquae does not have a telial stage, since only uredinia have ever been found, although this rust has been collected during October, November, January, and February on pods, leaves, and woody — and in three countries, namely, United States, Mexico, and Hawa RAVENELIA AUSTRALIS Diet. and Neg. O. Pycnia unknown. II. Uredinia amphigenous, very small, punctiform to irregularly oval, less than 0.5 mm. across, subepidermal, soon naked, rup- tured epidermis inconspicuous; urediniospores obovate, elliptic- obovate to subpyriform, light cinnamon brown, 13~20 by 25-32 yu, average for 20 spores 16.6 by 28.2y; walls 1.5-2.0p thick, slightly or not at all thickened above, concolorous, echinulate, germ pores 4—6, equatorial; paraphyses very abundant, incurved, dense, encircling the sori, ferruginous, hyphoid, more or less curved near apex, 10-17 by 50-67 w, average for 10 paraphyses 12.5 by 14.4 mu, walls about 2.5 w thick, an occasional paraphysis clavate, nearly colorless and with a solid stipe. Tlf. Telia amphigenous, punctiform to irregularly oval, less than o.5 mm. across, blackish-brown, subepidermal, early naked, ruptured epidermis inconspicuous; -paraphyses very — : encircling the sori and similar to those found in the u teliospore heads chestnut-brown, hemispherical, 67-110 w across, average for 20 heads 92.3 u, 7-11 cells across, 18-30 marginal ~ ee 22-64 immer ones, 40-94 ‘spores pet head, smooth; cysts 1, beneath entire head, i Mu, 66 BOTANICAL GAZETTE (yur The writer has not been able to obtain authentic material of this South Ameri- can Ravenelia, nevertheless he is assigning to this species the Texas Ravenelia collected on the same host (A. farnesiana), since its characters are practically identical with those described for the South American plant. RAVENELIA GRACILIS Arth. O. Pycnia not found in the Texas material. II. Uredinia epiphyllous, seated on slightly pallid areas, scat- tered, very small, less than o.4 mm. across, elliptical to irregularly oval, tardily naked, subepidermal, ruptured epidermis promi- nent; urediniospores ovate, ovate-fusiform to somewhat flask- shaped, usual shape ovate-flask-shaped, 15-21 by 30-45 mu, average for 20 spores 18.4 by 37.6; walls 2-2.5 uw thick, russet colored, sparingly echinulate, apex darker and slightly thickened, germ pores 4-6, in equator; paraphyses few, peripheral and also inter- mixed with the spores, hyphoid to subclavate, hyaline, walls thin, 4-7 by 35-50 n Ill. Telia ection: similar in size and shape to the uredinia, blackish-brown, subepidermal; teliospore heads dark chestnut- brown, hemispherical, 60-87 by 37—40 yw thick, average for 20 heads 73.8 by 39 wu, 5-6 spores across, 8-14 marginal spores, 4-12 inner spores, usual number per head 22-24, each spore on lower part of head bearing 2-4 small, hyaline tubercles, 2-5 » long, upper : portion smooth, or with 1-4 very short tubercles to each spore; _ _ cysts in 1 row, subglobose, few, as many as the marginal spores, united laterally and extending from periphery to stipe, sub- appressed, easily swelling and ome in ee; pedicel short, deciduous, colorless. — | ay Collected on Havardia brevifolias 6 miles from Brownsville, Texas, neat ave Pagans: November 10, 1916, by W. 4. Long | ae 6160). ‘Thndoce lyr Ff: ee te > cdliection which 4 S; Mexico, on an unknown host. Ts . Texas, ions le sin to be the same - a 1917] LONG—RAVENELIA 67 host and of the host found at Brownsville shows that the two are apparently identical. Ravenelia gracilis was —— common i in the vicinity o of B rownsville this species the urediniospores are given as obovate and the teliospore heads as bearing 4~-7 colorless tubercles to each spore. The writer, however, failed to find any obovate urediniospores in that portion of the type collection which is in his herbarium. The teliospore heads of the type show many heads with smooth tops but with short tubercles around the margin, while other heads in the same mount have shorter and fewer warts to each spore at the top than on the margin, thus agreeing in every detail with the Brownsville material. RAVENELIA LEUCAENAE Long This species was collected by the writer near Brownsville, Texas, on Leucaena pulverulenta. There are certain minor characters of this rust not given in the published description of it that are worth _ recording. The urediniospores on this host are mainly concolorous, often with the apex slightly thickened. The teliospore heads are 5-6 cells across, with 5-16 marginal spores and 3~14 inner ones, usual size 14-16 spores per head, each spore at top of head bears from o to 2-4 very short tubercles, while there are 4-6 Lome or slightly curved tubercles, 4-64 long, on each spo. cysts as many as marginal spores, agen extending ee fie po Ae cae This DR, =’ t rt 1) pee aten tlk = + warn, Lencsna sp. diversi, and L. esculenta. NEORAVENELIA HOLWAYI ‘Wietel) Long = II. Uredinia caulicolous, forming large, woody, perennial, fusi- form galls, 1-8 cm. thick A 4-12 cm. long, ceed —— over large areas oe ae galls, argus brown - spor _ oblong-linear, obovate, ¢ elliptical, clavate to subp sib : oe shape obovate to si clavate, 13-24 by eage eel for 120 | Spores 7 by 36 ms ie eee: = ck, slig , ed : 68 BOTANICAL GAZETTE [JULY III. Teliospores intermixed in uredinia on the galls; teliospore heads liver brown, hemispherical, often depressed, smooth, 60- 130, average for 40 heads 103m, 8-12 spores across, 20-38 marginal spores, 40-78 inner ones, average number of spores in each head 84-94; cysts globose to subglobose, in 2-3 rows, pendant beneath entire head, not coherent, slow to burst in water; pedicel hyaline or slightly tinted, short, deciduous, compound. This is a description of the gall-producing form of Neoravenelia holwayi. For several years the writer has been finding a species of Ravenelia on mesquite (Prosopis juliflora) which produces large, fusiform, woody galls. At first this rust was referred to Rovenclia ari ee, oe + careful examination of the gall led tl These smooth teliospores were so constantly Souké Sasictataid with certain types of galls that the writer made a special study of the galls found on mesquite. This investi- gation showed that there was a Ravenelia present on galls throughout a certain zone which constantly produced smooth teliospore heads. A careful study of the Ravenelia on these galls failed to show any positive differences either in the urediniospores or teliospores which would separate this gall-forming species from the ordinary leaf form of Neoravenelia holwayi. There are wide variations in shape and size of the urediniospores, as is to be expected when one oF galls as compared to those found on the leaves. The galls were found in localities where the leaves of the mesquite were abundantly infected with the usual form of N. kolwayi. In the vicinity of _ San Antonio and Uvalde the galls were rare, but at Corpus Christi and Browns- ville they were rather common. From Del Rio west to New Mexico and Arizona all of the galls found « ite were of a different type and were associated with the ti ues a of Desaulia arizonica. The galls produced by Neoravenelia holwayi are smoother and more fusiform than those caused by Renae Seen, in R: arizonica the galls are rather brittle, due to the larg yma i pe d in the gall vac ereennaanger when alive these galls have deep transverse fissures in their surfaces. which are borne the soliedaees and idicepoces. But few sori of any kind re were found on galls collected as late as November. The surface of the galls - baoph ater gendinie gis tacciie Se ; telio 1917] _ LONG—RAVENELIA 69 would be an undescribed species. As it now stands, this species parallels Ravenelia arizonica, both species having a leaf and a gall form; the galls of each usually bear only urediniospores, while teliospores are rarely found on the galls but usually occur on the leaves. Type material of each of the 3 new species of tae sho described in this paper has been deposited in the Pathological and Mycologi- cal Collections of the Bureau of Plant lednstyy: Department of Agriculture, Washington, D.C. OFFICE OF INVESTIGATIONS IN t PATHOLOGY . : : : no knowledge of this put ee til j oS ARBORES FRUTICESQUE CHINENSES NOVI. ITI’ CAMILLO SCHNEIDER Cotoneaster (Sect. CHAENOPETALUM Koeh.) oligocarpa, n.sp.— Frutex latus, erectus, ad 4 m. altus; ramuli hornotini initio to- mento villosulo flavescenti-cinereo adpresso obtecti, annotini satis glabrescentes, fusco-rubri, vetustiores glabri, plus minusve cineras- centes. Folia subcoriacea, partim persistentia, ovalia, obovato- elliptica vel praesertim versus apicem ramulorum ovata (in specimine florenti distinctius obovata), apice acuta et mucronulata vel satis obtusa et interdum subrotundata, basi pleraque late cuneata, 2.5—-5 cm. longa et 1.2—-2.5 cm. lata, superne saturate, sed ut videtur obscure, viridia, initio laxe villosula, biennia costa impressa excepta glabra, subtus modo ramulorum novellorum dense tomentosa, etiam adulta haud vel tantum in costa elevata _paullo glabrescentia, in facie sub microscopio papillis distinctis = ee, nervis coments superne plus minusve impressis insecus 8—12; petioli dense tomentosi, _vix ultra 6 mm. longi; stipulae triangulari-lanceolatae, acuminatae, petiolis breviores, subtus dense tomentosae, superne glabriores. Corymbus satis densus, multiflorus, ad 4 cm. (vel ultra ?) latus et ad 3.5 cm. altus, villosus, bracteis bracteolisque deciduis sub- ulatis circ. 3 mm. longis; pedicelli 1-3 mm. longi, ut villosi; flores albi; receptaculum ovato-turbinatum ut sepala Lite triangularia circ. 1-1.5 mm. longa apice glanduloso-mucronulata ints giabes, eae eee foneteahen, ad 2.5 mm. longum; Th L en ae ‘ thunk Af ‘¢hia ornicok: me Mabenia ia proposed by me in the previous paper (Bor. Gaz. 63: ‘§19-521. r917) have been described by ‘pass Males” (Sor Rey. Bet. Gand. Basbege sok - Old World species of the BA, nos 20, 9° Janmary 1082). — tic wes 2 te same as M. rade Takeda owe rh nsis. von omy eb edt rere by TAREDA to ib new M. I that: the two s 1917} SCHNEIDER—NEW CHINESE PLANTS Ce | petala orbicularia, circ. 2.5 mm. lata, basi unguiculata, intus pilosula; stamina 20, petalis paullo breviora, antheris ut videtur violaceis; carpidia 2, apice sparse villosa, stylis quam stamina fere longioribus stigmatibus capitatis planis. Fructus parvi, rubri; subglabri vel satis villosuli, plus minusve turbinati, 4-5 mm. longi, apice circ. 3 mm. crassi, sepalis extus villosulis incumbentibus fere clausi; pyrenia 2, obcordato-ovoidea, circ. 3.5 mm. longa et infra medium 2.5-3 mm. lata, stylum in apice vel paullo infra gerentia, ventre leviter carinata, subnitentia, dorso paullo sulcata, basi hypostylii leviter constricta, hypostylio circ. trientem dorsi occupante villosulo. Yunnan boreali-occidentalis: in dumetis ad vias inter Ho-ching et Li- chiang-fu, alt. circ. 2600 m., 25 Septembris 1914, C. Schneider (no. 77 typus in Herb. Arb. Arn. et Hb. Schneider).—Szechuan australis: ad vias declivibus montium prope Wo-lo-ho, alt. circ. 2800 m., 13 Junii 1914, C watis). glabrescen ieee ippatiie. Cc salicifolia var. rugosa R. and W. and var. floccosa R. and W. differ by the same characters of the leaves and by their larger more subglobose fruits. Its nearest relative may be C. Harrowiana Wils., of which ‘have not yet seen the fruit; but the old leaves : glabrescent beneath. Having introduced C. ‘oligocarpa into cultivation, cs has to be decided by observation of li; gc or only a variety of C. Horrewiana which comes from southern Yanna. C witdais dad ta ection ©. Harrowiana and C. oligocarpa a group of very closely related which may So iced ace a oo ee ee : on the under surface, — of suntan the — fo Lae 72 BOTANICAL GAZETTE [JULY tantum in costa impressa pilosa, facie plana sed tenuissime reticu- lata nervis non incisis, subtus dense ut ramuli tomentosa, etiam biennia tantum in costa prominente paullo glabrescentia, nervis lateralibus utrinsecus 5-7 vix vel paullo prominulis; petioli vix ad 5 mm. longi, dense tomentelli; stipulae anguste triangulari-lanceo- latae, acuminatae, petiolis breviores, subglabriores. Corymbus pluriflorus, ad 3 cm. latus et 2.5 cm. longus, dense villoso-tomento- sus; pedicelli 1-2 mm. longi, ut pedunculi tomentelli, bracteis bracteolisque deciduis; flores ignoti; fructus parvi, obscure rubri, turbinati vel globoso-turbinati, circ. 4 mm. longi et 3 mm. crassi, plus minusve villosuli, apice sepalis incumbentibus extus villosis fere clausi; pyrenia 2, circ. 3 mm. longa et 2.5 mm. lata, obovoidea, ventre plana, satis laevia, nitidula, dorso leviter rugulosa, stylum apice gerentia, hypostylio circ. trientem dorsi occupante villosulo. Yunnan boreali-occidentalis: ad latera orientalia montium niveorum prope Lichiang-fu, alt. circ. 3000-3200 m., Octobri 1914, C. Schneider (no. 2676; typus in Herb. Arb. Arn. et Hb. Schneider). The fruits of this species are extremely like those of C. oligocarpa Schn., previously described, but in its narrow elliptic obtuse leaves, which are smooth above and show very little prominent veins beneath, C. Vernae differs widely from all the species mentioned above. It seems to be more closely related to C. pannosa Fr. which, however, can easily be distinguished by its more ovate acute or shortly acuminate leaves, and by its larger fruits, the sepals of w are more erect. Iam unable to identify my no. 2676 with any Chinese species hitherto described. I introduced it into pmiahinrrete (seed | no. 578); and — vations of living plants may give further indications of this apparently well marked species. It is named for my daughter Verna. PRUNUS LATIDENTATA Koeh., var. trichostema, n.var.— _P. trichostoma Koehne in Sargent, Pl. Wils. x: 216. 1912.—A typo non nisi — intus et stylis basi distinctius — differre videtur. ; : - Szechuan australis: ‘in regione Yen-yiian fies, inter ‘vedes Ka-la-pa et Liu-ku, i in sepibus, alt. circ. 3200 m., 17 Maji ror4, C. Schneider (no. 1210; _ frutex ad 2 m. altus); inter viculos Hun-ka et Wo-lo-ho, alt. circ. 3300 m., 13 june 1914, Cc. Schneider (no. 3520; arbuscula vel arbor ad Gémalta). cording own statement, there is really no other difference — | Detween P.laidenat nba sand P.ichastoma than the vabsionece lai the eal ao So far as I can j s bef : : De 1917] SCHNEIDER—NEW CHINESE PLANTS 73 POTENTILLA ERIOCARPA Wall., var. cathayana, var. nov.— ? P. eriocarpa Franchet, Pl. Delav. 211. 1889, non Wall., sensu Lehmann et Wolf; Diels in Not. Bot. Gard. Edinbgh. 7: 157. 1912, 387. 1913.—A typo a cl. Lehmanno depicto recedit foliolis omnibus sessilibus, inflorescentiis ad 3-floris, sepalis externis ovato- lanceolatis subacuminatis quam interna paullo latiora saepe dis- tinctius acuminata vix vel paullo brevioribus. Yunnan boreali-occidentalis: in fauce infra glaciem parvam montium niveorum prope Lichiang-fu, in rupestribus calcareis, alt. circ. 3900 m., 17 Augustii 1914, C. Schneider (no. 2274; typus in Herb. Arn. Arb. et Hb. Schnei- der; suffrutex floribus magnis luteis, ramulis floriferis 5-15 cm. altis). According to the figure given by LEHMANN and to WoLr’s description, the typical P. eriocarpa Wall. has “sepala externa late elliptica obtusa vel rotundata,”’ and the leaflets are described as “plus minusve longe petiolulata (saltem terminale)?’ The petals of var. cathayana seem also to be much more emarginate than those of the type. Rubus (Subgen. Iparosatus Focke, sect. IDAEANTHI Focke) testaceus, n.sp.—Frutex habitu R. Jdaei ad 1.5 m. altus, dumeta formans; rami vetustiores teretes, aculeis paucis aculeolis sparsis vel crebris rectis armati, satis dense villosuli et glanduloso-setulosi, setulis intermixtis, partim glabrescentes et testacei; ramuli floriferi — ut videtur nondum satis evoluti ad 10 cm. longi, cum petiolis pedicellisque densius griseo-villosuli et etiam glanduliferi et parce setulosi. Folia visa omnia ternata; foliola ovato-rhomboidea vel rhomboideo-orbicularia, iis R. schizostyli ex icone a cl. Focke in monogr. p. 206 dato satis similia, terminalia petiolo ad 1 cm. longo © suffulta, maxima visa ad 3.5 cm. longa et 3 cm. lata, apice rotun- data, obtusa (vel rarius in foliolis satis juvenilibus oblongioribus _ subacuta), lateralia subsessilia, ad 1.8 cm. longa et 1.5 cm. lata, omnia subaequaliter satis grosse dentata vel inaequaliter dentato- _ _ Serrata, sublobulata, _Superne- satis flavo-viridis, laxe vel initio 7 ‘ os glabriuscula, in costa. ‘nervisque lateralibus oteaade 7 G-) Q ce & ek hirta_ et pe minusve e gland ul losa 5 petioli ad > cm. longi; | - vesert op extus m villoate ee tae 74 BOTANICAL GAZETTE _ [jury bractea stipulis simillima instructi; calyx externe modo pedicellorum villosulus, glanduliferus et parcissime setulosus, sepalis lanceolatis acuminatis margine albo-villosis circ. 7 mm: longis patentibus intus basi glabrioribus; petala oblonga vel satis anguste obovato- oblonga, versus apicem acutiusculam undulato-marginata, basim versus longe cuneata, intus sparse pilosa, demum ut videtur patentia, sepalis subaequilonga et ultra medium circ. 3-3.5 cm lata; stamina in flore ut videtur erecto-patentia, circ. 70-75, filamentis glabris longioribus petalis subaequilongis; carpophorum pilosum; carpidia circ. 30, 4.5+5 mm. longa, stylis glabris, ovariis ima basi pilosis et dorso saa parcis praeditis; discus glaber. Fructus ignoti. Szechuan australis: in regione Yen-yiian Hsien, inter viculos Ka-la-pa et Liu-ku, alt. circ. 3500 m., 17 Maji 1914, C. Schneider (no. 1269; frutex ad 1.4 m. altus, dumeta formans, foliis valde juvenilibus); eodem regione, ad viam inter Liu-ku et Kua-pie, alt. circ. 2800 m., 19 Maji 1914, C. Schneider = 1213; flores rubri).—Yunnan bores ooctdentatis: in regione Yung-ning, us pagum Mu-ti-chin, alt. circ. 2800 m., 23 Junii 1914, C. Schneider (no. stn typus in Herb. Arb. Arn. et Hb. Schuasiden). Judging by the shape of the leaves, this species seems to be very similar to R. schizostylus Lév., which I know only from the figure given by Focke in his Mon. Gen. Rubi Prodr. in Bibl. Bot. 72: 206. fig. 83. 1911; but according digo acts, ner poadeiaie clean cea cagehinn ee having . foli pilis adpressis albis.”” R. cima Packs: Le. 204. fig. By ak and Szechuan, has white or pink flowers, and is otherwise extremely different. Another species to which R. festaceus may be related is R. kanayamensis Lév. and Van. in Bull. Soc. Bot. France 53: 549. 1906 et apud Focke, l.c. 205, from Japan, of which the leaves are described as “in utraque angular: et _ parce pilosa,” but it has an “inflorescentia laxe effusa,” and, according to - Focxe’s statement, “revocat R. id. subspec. strigosum,” he shape of the leaves of which is entirely different ee zles tothe pale brick red color ofthe older serge cage hes. Ate false, Se. | ee ee 6-jugis, tg17]} SCHNEIDER—NEW CHINESE PLANTS . 75 pedicelli ad 18 mm. longi, plus minusve tomentelli, apice excepto non incrassati. Yunnan boreali-occidentalis: in declivibus herbosis calcareis montium Tsang prope Tali-fu, alt. circ. 2800 m., Augusto 1914, C. Schneider (no. 2526; typus in Herb. Arb. Arn. et Hb. Schneider). This variety agrees well with typical R. Mairei Lév. except that the leaves have 5-6 pairs of leaflets instead of only 2-4 pairs. Unfortunately the fruits of the type are still unknown. ReEHDER.and Witson in Sargent, Pl. Wils. 2: 344. 1915, say that R. Mairei “is probably nothing more than a very hairy and small-leaved variety of R.. omeiensis Rolfe.” In my opinion, it seems much more closely related to R. sericea Ldl. which, however, comes very near R. omeiensis. The new variety may be identical with the true R. sericea, f. pteracantha Franchet in Pl. Del. 220. 1889=R. sericea Crépin in Bull. Soc. Roy. Bot. Belg. 25: 9. 1886, ex parte, quoad no. 861 Delavayi, which he describes as having “folia majuscula utraque facie sericeo-tomentella, ” ‘but he does not mention the number of the leaflets neither does CREPIN. pteracantha in Gard. Chron. III. 28: 260. figs. 98, 99, 1905; and in Bot.. Mag. 134: pl. 8228. 10908, which is the same as R. omeiensis f. pteracantha R. at W. in Sarg., Pl. Wils. 2: 332. 1915. he typical R. omeiensis Rolfe is well characterized by its OP ee eaten SE the leaflets of which are entirely glabrous or hairy only on the beneath, and by the distinctly thickened and colored (yellow or red) footstalks of the ripe fruits (see Bot. Mag. 138: pl. 8471. 1912) ; but there are certain — hairy forms with almost subsessile fruits and f ewer leaflets which come very near to R. Mairei as well as to R. sericea. The type of R. sericea as represented by Liypiey in his Rosac. Monogr. 195. pl. 12. a has 7-1r leaflets which le revétement de ses axes et de ses feuilles.”” ‘By Wusox, Foazsst, and my- self many forms have been it into culti so : able to judge the value of the different characters p _ fruits, ar ai “ais RIE 76 BOTANICAL GAZETTE [JULY vel breviter acuta, basi plus minusve rotundata, rarius late cuneata, lateralia inferiora minora (13—) 15-22 mm. longa, (8-) 10-15 mm. lata, superiora majora ad 3.2 cm. magna, terminalia superioribus plus minusve aequalia sed saepe paullo latiora, margine dupliciter inaequaliter glanduloso-serrata (sublobulata) dentibus majoribus mucronulatis porrectis dorso denticulas 1-3 gerentibus, superne viridia, in sicco leviter glaucescentia, laevia, glabra (interdum sparsissime glanduloso-pilosa), subtus viridescentia, dicoloria, in costa et etiam partim in nervis lateralibus utrinsecus 5—8 paullo prominulis satis rectis plus minusve pilosa et etiam ut in facie pilis glanduliferis crebris conspersa (oculo nudo quasi nigro- punctata), rete nervillorum subvisibili; petioli 2-3.5 cm. longi, ut rhachis plus minusve dense villosuli, stipitato-glandulosi et setis aculeolisque sparsis muniti; stipulae satis evolutae, ad medium adnatae, 10-13 mm. longae, auriculis latis acuminatis, margine dense glanduloso-ciliatae, ceterum ut folia pilosa et glandulifera. Flores kermesini, stiaveolentes, circ. 3 cm. diametientes, solitarii vel 2-3 apice ramulorum ad 8 cm. longorum terminales; pedicelli 10-12 mm. longi, basi bracteis ovatis vel late ovatis apice subito acuminatis ad 12 mm. longis et 8-9 mm. latis dense glanduloso- ciliatis suffulti, glabri, interdum fere nudi sed plerique crebre stipitato-glandulosi; receptaculum ellipsoideo-oblongum, glabrum, nudum; sepala ovato-oblonga, extus glabra vel interiora versus — marginem tomentella, intus tomentosula, eglandulosa, post flora- tionem reflexa; alabastra ovata, obtusa; petala late obovata, _ emarginata, ad 2 cm. longa et 1.7 cm. lata; stamina numerosa, antheris luteis ovalibus; styli liberi, circ. 5 mm. exserti, staminibus _longioribus vix breviores, villosi. Fructus ignoti. oS Szechuan australis: inter urbem Yen-yiian Hsien et viculum Hun-ka, ad vias, alt. circ. 2600-2800 m., 11 Junii rora, C. Schneider (no. 1484; typus in Herb. Arb. Arn. et Hb. Schneider). This species seems to me most closely related to R. Sweginzowii Koehne : = fom tame es Weddle, Rep. Spec. rx: 531. fig. 3) and R. eS Wis. (see Bot. Mag. rgo: i. 3569), he oe eo disting = fo having 7-9 leaflets and a different kind of wide-based Liseovd R atom pe 1917] SCHNEIDER—NEW CHINESE PLANTS "7 Rosa SOULIEANA Crép. var. yunnanensis, var. nov.—R.: moschata var. yunnanensis Focke in- Not. Bot. Gard. Edinbgh. 5:69. 1911, nom. nud., non Crépin apud Franchet; Drets, l.c. 7:124. 1912 et 394. 1913, nom. nud.; R. Soulieana R. and W. in Sarg., Pl. Wils. 2:314. 1915, quoad synon. Fockii et specim. Forrestii, non Crépin.—A typo recedit rhachi foliorum et costa foliolorum subtus puberula, pedicellis receptaculisque minute flavo-glanduloso-pilosis et etiam interdum pilosulis. Szechuan australis: inter viculos Wo-lo-ho et Hu-ma-ti ad viam versus Yung-ning, alt. circ. 2800 m., 14 Junii 1914, C. Schneider (no. 1549; frutex ad 2.5 m. altus, patenter dense ramosus, floribus albis odoratis). The main difference between the type and this variety seems to be the fine pubescence of the rhachis and of the midrib of the under side of the leaflets, MORIN’S plant, probably, came from the type plant i in the Jardin des antes - Paris. The shape of the leaflets, which are described by FRANCHET as “courtes, ovales et plus ou moins arrondies, 4 base arrondie, obtuses- arrondies au sommet, plus rarement trés brusquement mucronées,” varies to a certain — degree, and especially the leaves of ForrEst’s no. 2370 from Lichiang, which is the type of var. yunnanensis of Focke, are rather acute at both ends. VIBURNUM CYLINDRICUM Ham., var. crassifolium, n. var.— aves crassifolium Rehder i in Sarg., Pl. Wils. 2:112. 1913. oe A typo cum varietate ut videtur formis intermediis conjuncto | differt praecipue inflorescentiis plus minusve vel satis dense aes centibus. Szechuan australis: in regione Yeu yeaa Hsien versus occidentem inter viculos Hu-ma-ti et Wo-lo-ho, alt. circ. 2800-3000 m., 14 Junii 1914, C. Schnei- der ae — —— ase #¢ °. Om Pibusens oe en S hte Said ie ee free -3 metals); eodem loco, Octobri = *9E4, C. Schneider ced brgees ee 78 BOTANICAL GAZETTE [yuLY prope Kua pie, alt. circ. 3000 m., 21 Maji 1914, (no. 1345; frutex vel arbor, 3-6 metralis); in regione Hua-li, in dumetis declivium ad flum. Yalung, alt. 2300 m., 30 Maji 1914 (no. 1395). VIBURNUM CALvUM Rehd., var. puberulum, n. var.—A typo praecipue recedit: ramulis hornotinis et saepe annotinis biennesque et etiam inflorescentiis plus minusve puberulis.——Fructus atro- cyanei, nitiduli, ovato-globosi, circ. 5 mm. longi et 4 mm. crassi, iis V. propinqui similes sed minus distincte apiculati; semina ovoideo-globosa, ventre leviter sulcata, albumine ruminato. Szechuan australis: inter Hoh-si et Yen-yiian Hsien prope pagum Lo- ma-pu, in dumetis montium, alt. circ. 2200 m., 9 Maji 1914, C. Schneider (no. 1146; frutex virgultus, 1.5-2 m. altus, floribus albis, fructibus atrocyaneis) ; in regione Kua-pie, in declivibus dumosis calcareis montium, alt. circ. 3000 m. 20 Maji 1914, C. Schneider (no. a typus in Herb. Arn. Arb. et Herb. eider; frutex sempervirens, 1 m. altus, fructibus nitidis nigris). According to the shape and he athe of the leaves, and to the size of the inflorescence, this form is very similar to the typical V. calowm Rehd. from southern Yunnan, of which the fruits are not yet known. The fruits I collected are about the same as those of V. propinqguum Hemsl. which, however, can easily be distinguished by its 3-nerved leaves. There is another very interesting species I found in Yunnan boreali-occidentalis: inter Hoching et Teng-chuan, in silvis apertis _ prope Sung-queh versus angustias montium, alt. circ. 3200 m., 29 Sept. 1914 (no. 2873; frutex 3-metralis). The shape of the ovate-oblong or oblong-elliptic leaves, which measure up to 8 cm. in length and 2.8 cm. in width, is similar to those of V. propinquum, but they are not distinctl te and not 3-nerved at the base, but have the same ‘nervation as V.caloum. The fruiting corymbs are small, and bear only a few fruits, which, unfortunately, are not yet fully ripe. They are almost globose, and about’5 im. in _ diameter. I cannot refer this form to any sj th described _ £ - _ from China, but I believe it is very near or the same as V. atro- : aoe cyanea oe C. B. Clarke apud Hook. and es FL. Brit. Ind. BRIEFER ARTICLES ' ANELSONIA, A NEW GENUS OF THE CRUCIFERAE As GREENE remarked long ago, the so-called natural families, as Umbelliferae, Labiatae, and Cruciferae, contain relatively few natural genera, and perhaps in no group of plants are generic limitations harder to define than within some sections of the Cruciferae. Consequently, there have often been included under one generic name plants that in point of fact bear little real relationship to one another. The genus Parrya, as it has been treated by many recent authors, furnishes, we believe, an example of this pisinin pretation - generic Henitaticms, This genus was drawn by Brown toi of the far North, all characterized by showy purple- red flowers and glabrous (or hirtellous with simple hairs) foliage. In 1891 GREENE (Fl. Fran. 1:253) referred to Parrya, Hesperis Mensziesii Hook., a plant previously made the type of a new genus by NuTTALL (T. and G., Fl. N. Amer. 1:89. 1838) under the name Phoenicaulis cheiranthoides Nutt., and possessing much the same aspect as the species included by Brown in his genus, but with the foliage whitened by a thick covering of branching and stellate hairs. A onofthis plant with the typical members of Parrya has disclosed the fact, however, cS that technical but readily discernible differences other than the char- __ acter of the pubescence exist between Parrya and Phoenicaulis. _ more important of these are the lack in the latter of the conspicuous — network of superimposed fibers that characterize the septum of sn the absence of the loose epidermis so } omi t the seeds of the latter genus, the tort : species of Parrya, and the ea of characters of this type bm thee | ‘proper delineation of — in the i 80 BOTANICAL GAZETTE [JULY on vegetative characters or places too much dependence upon the often fickle ‘“‘aspect.’’ Circumstances of this nature doubtless contributed largely to the treatment by NE son (Proc. Biol. Soc. Wash. 18:187. 1905) of Phoenicaulis Menziesti as a species of Arabis, a disposition that was adopted later by NELSON and Macsripe (Bort. Gaz. 55:374. 1913). It must be admitted that the arguments in favor of this treatment are far from weak; on the other hand, the highly technical nature of the characters to be considered in the proper definition of groups in a natural family must be borne in mind, and PrRantt has used to advantage, in “keying”? Phoenicaulis and Arabis, the type of characters that furnish the best contrasts between Parrya and Phoenicaulis. The very possi- bility of considering P. Menziesit as an Arabis becomes, therefore, a strong argument for its retention as a genus distinct from both Parrya an We now come to a consideration of the plant which prompted these observations. This plant was described by Gray (Proc. Am. Acad. 6:520. 1866) from meager material that was far past condition as Draba eurycarpa, and recently has been redescribed as Parrya Huddelliana A. Nels. (Bor. Gaz. 54:139. 1912). Here again we have an instance of the similarity of genera in this family, especially as regards vegetative characters. This plant would not seem at all out of place in Draba were aspect the only criterion we had to judge it by; and indeed the original ; consists only of two small plants which are so mature that the seeds have all fallen. But upon examination of complete material it becomes obvious that Gray’s species is allied to Parrya and _ Phoenicaulis. Itis not satisfactory, however, to refer it to either of these _ The branching pubescence, the inconspicuous white flowers, the subentire stigma, the broadly ovate-lanceolate pods, and the nearly membranous septum are some of the characters that forbid its reference to Parrya. The loose cellular testa about the seeds, the not at all tortu- ous areolae, and the i inconspicuous flowers are also characters in direct re contrast to Moreover, there is the unique habit which suggests. Draba rather than either of the genera to which it is most nearly related, but consideration of it as a Draba (to mention one outstanding feature) is out of the question because of the singular seed 3 coat Although this is suggestive of the seed coat of Fore, it is of a different quality and is not winged. | Now in the proper generic allocation of these plants c “on: be given only to the value of 1917] BRIEFER ARTICLES 81 and distinctive; and it seems to us that there is only one possible inter- pretation of the problem which will conform to what experience has shown to be the logical and practical treatment of cruciferous groups. In pursuance of this view it becomes necessary to consider Draba eurycarpa as representing a generic type intermediate in some respects to Parrya and Phoenicaulis, and more closely related to these genera than to any others, but at the same time more distinct from either of these than they are from each other. In recognition of the notable work of AVEN NELSON, we propose that this genus bear the name Anelsonia. The — characters of these related genera may be sum- , marized as follows Pods ovate-lanceolate, mid-vein obscure; sectame merely ‘membranous ranous; seeds with a loose cellular epidermis, not margined, areolae not tortuous; pubescence of branching hairs; petals white, little exceeding the pubescent eras: Shes SS 2... ee ee _Anelsonia Pods narrowly ensiform or more or less attenuate at both base and apex mid-vein evident; seeds smooth without loose cpaletnis or, if this i is present, more or less margined; uae usually red purple, di Pets more or less attenuate at both base and apex; septum bearing a conspicuous network of superimposed fibers; seeds with a loose cellular epidermis usually more or less winged, areolae not tortuous; | Pods narrowly ensiform; _ septum merely ¥. yy tM tee, and stellate; stigma subentire. Be Ae rrgec eis ae . Phoenicaulis 2 Anelsonia, gen. nov.—Siliqua compressa ovato-lanceolata costa media i oe septo membranaceo-hyalino, evanido, Stigmati fere a Anelsonia_ ann (Gray), oo a eurycarpa Gx, a eae ‘Am. Acad. ee on CT halhaas Shares: A. eapeae ot. € CURRENT LITERATURE BOOK REVIEWS Researches in plant physiology ATxktns' has written an interesting little book, the aims of which can best be expressed by quotations from the preface. ‘‘The general aim of the book is to present to senior students and investigators the results of recent work in a few of those branches of plant physiology which are at present attracting . attention.” ‘‘By such a presentation of portions of the science which are still in a state of rapid growth, it is hoped that further investigation will be stimu- lated. The choice of material by the author was, to a considerable degree, infucoced bad his Famiferity with certain Subjects of general interest, portions tally by the staff of the School of Botany, Trinity College, “Dublin. Upon these, rather than upon other researches of equal or greater importance, he has felt qualified to write, on account of his first-hand knowledge of many of the methods employed. A small amount of hitherto b included. tal A list of the chapter headings gives an idea of the content of the book: Ss The carbohydrates of the angiosperm leaf i in relation to photosynthesis; feth carbo- ‘ductivities in plants, and the factors which influence them; X. Osmotic pres- sure in relation to plant distribution, m logy, and cell division; XI. The functions of the wood; XH. The plant oxidases; ZXUIL. The oxidases in rea “ror7] ‘CURRENT LITERATURE : 83 NOTES FOR STUDENTS Taxonomic notes.—Burt? has described a new species of Pistillaria (P. Thaxteri) which he records as the smallest known hymenomycete. It was collected in Connecticut, and is so minute that the “‘fructifications are not visible to the naked eye unless rendered so by special illumination and back- ground.” The fructifications were observed scattered on the surface of very rotten wood, “merely gregarious, not united into clusters,” and as many as II5 were counted on an area 2X0.5 cm. The fungus is remarkable not only as the smallest known “toadstool, ” but also for its extreme simplicity of structure. FERNALD has described a new species of Juncus (J. pervetus) from Cape Cod, resembling J. Roemerianus in many particulars. It is stated that this new species “is one of the many remarkable species of world-wide affinities which are being discovered so frequently on the coastal area of southern New England and southeastern British America.” Gates‘ has had occasion to investigate Trillium in connection with his work in genetics, and has been impressed with the great variability of the genus in certain organs. In attempting to delimit the species, he recognizes SE species with 9 varieties. T. venosum is described as a new species from described in T. luteum, T. lanceolatum, T. grandi- florum, and T. ovaium. ee Eee enn of reciaten © he eee se brought together, and their number is remarkable. The author suggests that the genus Paris has Seon Ginited fom the T. erectum group, and that Medeola Sin ction be studies of Senecio, has presented § Losarty comprising 16 species, 4 of which are described as new — Hov a ve ’ > & eperations on August tr, (4 in water ona ret about 2 miles off 84 BOTANICAL GAZETTE funy MacKeEnzig,’ in continuation of his studies of Carex, has presented the “Californian representatives of the Ovates.” The list includes 25 species, 15 of which are described as new. ' Rosrnson® has published a detailed monograph of the American genus Brickellia. The need of it, the author remarks, ‘‘ presents no unusual condition among the larger genera of the Compositae.” The gi species, 11 of which are new, are grouped in 9 sections. The systematic presentation is preceded by a full discussion of the diagnostic value of the characters used. RYDBERG,’ in continuation of his studies of the Rosaceae, has investigated the species of Rosa occurring in — and Nevada. He recognizes 34 species, 12 of which are described as Tipestrom™ has described a new tie (A. platyphyllum) from the Wallowa National Forest of Oregon.—J. M. C. Effect of carbon dioxide on respiration—Kipp" has studied the effect of various concentrations of carbon dioxide on the rate of anaerobic and aerobic respiration of seeds of peas with testas both intact and removed. The work is marked by brilliancy of design, and in the main of aepigaroae In concen- trations of CO, ranging from o to 50 per cent, the d anaerobic respiration is proportional to the square root of the concentration. As the concentration rises above 50 per cent, the depressing effect falls more and more behind the square root of the concentration. Carbon dioxide also depresses aerobic respiration when measured either by oxygen consumption or CO, production. In the latter case the concentration effect is similar to that in anaerobic ew soidgina is deficient, CO, has no depressing effect . as ; atio occurring in n starving tissue) i is thus depressed The work throws considerable " Inwotk ofthis sft ee bold be aretha the lt sterile and that ca om Ce ction is that of the s EERE | ssdicatac a scp aiid clcietion OF ema Ase aad aeto apodemicit 1917] MacCAUGHEY—HAWAHAN FLORA 97 plant or group of allied plants has existed in the islands, the botanist would be well advised to consider the fauna that is especially attached to these. When one considers that trees little modified from foreign species, for example, Acacia koa or Sophora chrysophylla, possess a great endemic fauna, not only species, but even genera of birds and insects, quite restricted to or dependent on them, and that some of these creatures are certainly themselves not less remarkable in their peculiarities than the most peculiar of the composites or lobelias, we may hesitate to attribute such plants to a later era than many other elements of the flora, which at first sight appear far more ancient. Again, while in the islands an abundant endemic fauna restricted to a plant indicates an ancient occupation by the latter, the absence of such a fauna does not necessarily imply the reverse. In a fauna of comparatively few types it may happen that few or no species have reached the islands that could become adapted to certain elements even after great length of time. [I think that those who are in favor of the comparatively frequent accession of immigrants to account for the great series of allied species, or groups of allied eh ee ee HircH- cock remarks in writing of the most recent portion of the group, the still active Mauna Loa on Hawaii, when one considers how little the bulk of the mountain is made up of the few flows delineated on the map, and how small | by that there ng i a f£ sl sy Le 8 ie e : i aaeeined rap agelvors sae ieaemeanny "hae bra eed ala up long before the Tertiary period. And here he is ee eee e - Iti is significant that the gy no ms are Coreikery absent oo - the native Hawaiian dora: ao ‘and conifers I have been intro- — duced in recent years. 98 BOTANICAL GAZETTE [AUGUST 1. Littoral—(a) Humid littoral, along the windward coasts; (6) arid or semiarid, along leeward coasts and coasts far removed from the mountainous interior. 2. Lowlands.—Up to tooo-1500 ft., with humid and arid sec- tions, depending upon relation of topography to trade winds and distance from interior mountains. 3. Forest zone.—(a) Lower forest (1000-2000 ft.), with humid and arid sections; in early times this zone extended much farther seaward on the various islands than it does now; (6) middle forest Fic. 2—View from a dividing ridge between 2 long humid valleys, looking toward the head of Kau-kona-hua Valley; fog-covered summit ridge, elevation 2500 ft., seen in distance; entire region covered with dense and unbroken rain forest; on slopes and ridges trees average 15-30 ft. in height, in valley and ravines they rise to 40-6o ft.; annual precipitation at head of this valley approximates 200-300 inches. (1800-5000 ft.), range variable, with humid and arid sections; this comprises in the humid areas the typical Hawaiian rain forest, highly hygrophytic and very rich in endemic forms; (c) upper forest (s000-go00 ft.), restricted to the high mountains of Maui and Hawaii. 4. Summit regions.—(a) Xerophytic summits (gooo—14,000 ft.); high mountains of Maui and Hawaii; (0) hygrophytic summits : rine it}; peaks rising into the cloud zone, with summit bogs. 1917] MacCAUGHEY—HAWAIIAN FLORA 99 Palms The palms furnish an interesting illustration of the 3 floral elements: indigenous, native introductions, and modern intro- ductions.** The capital city, Honolulu, is a veritable palm garden; there are some 80 species represented, which have been gathered from all parts of the tropics. There is scarcely a home or yard without its palms; some of the finest driveways are colonnaded with such stately species as Oreodoxa regia and Phoenix dactylifera; Fic. 3.—Arid, deeply eroded summit ridge, elevation 2000 ft., of eastern Koolau Mountains; absence of vegetation due partly to aridity, partly to devastations of goats; remnants of original forest cover occur here and there in hanging valleys near sky line and in deep ravines. and certain of the old estates, the famous Hillebrand gardens for example, are crowded with rare and choice specimens. The only palm introduced by the natives (and this introduction is neces- sarily more or less theoretical, in the absence of historical records) was the coco palm. This species (Cocos nucifera) is widely spread throughout Polynesia, and in early times formed a characteristic ? feature of many Hawaiian shores and beaches. : = es, ¥, The « economic woods << Hawaii, Forest a hee! 1916. - uarterly 14:696- 100 BOTANICAL GAZETTE [AUGUST The indigenous palms are confined to the single genus Pritchardia, and are allendemic. There are a number of Hawaiian species, perhaps a dozen. The exact botanical status of these has not as yet been fully determined. The species of Pritchardia occur mainly in the rain forests and along exposed humid summit ridges. They are scattered, are usually solitary or in small clumps, never form pure stands, and constitute a very minor element in the forest. From the standpoint of abundance or striking features, Fic. 4.—Xerophytic promontory, Ka-ena Point, a typical “dry ridge” formation; other similar ridges, separating arid valleys, seen to the right; in foreground a coral beach formation covering ancient lava beds; note stratification of lava flows in the faces of promontory, also extensive talus slopes. the native palms are as disappointing as the native orchids. They occasionally attain considerable height (40-50 ft.), but are cus- tomarily of short or even dwarf stature. Pritchardia is confined to the islands .of the Pacific. The Hawaiian species show close affinities with those of the South Seas. _ Many of the other monocotyledonous families are but meagerly — The * Orchidaceae, for ee that attain unrivaled : 1917] MACCAUGHEY—HAWAIIAN FLORA IOI luxuriance and marvelous specialization in many tropical regions, have only 3 species in Hawaii, and these are all shy, poor, homely little plants."© Pandanus is represented by one species, formerly abundant in the lowlands. Freycinetia Arnotti Gaud. is a tall woody liana, common in the lower forest zone of all the islands, and often forming dense jungles. The liliaceous plants of Hawaii are in part woody species; none are bulbs, and none have particularly showy flowers. Of the Fic. 5.—Lava flow of the smooth or “pa-hoe-hoe” type; shows invasion by lichens and ferns; in arid situations lava flows retain a new, fresh appearance for a long period of years; under humid conditions they rapidly disintegrate and are soon covered with plant life. 5 genera, 3 are monotypic: Cordyline terminalis, a tall shrub; Dracaena aurea, a tree; and Dianella odorata, a large herbaceous perennial; all are abundant. Asielia and Smilax are confined to the forest and upper zones, and none of the group occur on the coastal plains or lowlands. There are no “‘fields of lilies’ in Hawaii. Commelina nudiflora is exceedingly abundant in moist * MacCavucney, V., The orchids of Hawaii. Plant World 19:350-355. 1916. ¥O2 BOTANICAL GAZETTE [AUGUST situations throughout the lowlands, forming pure stands and smothering other vegetation. The large and highly diversified propiend order of the aroids has no place in the Hawaiian flora, except 2 naturalized species, Colocasia and Alocasia, introduced by the ancient Hawaiians. Colocasia antiquorum, the kalo or taro, was the staple food of the primitive Hawaiians. The plant was raised both in irrigated fields (loi) and on the uplands (Kula). Alocasia macrorrhiza, the ape or giant taro, was raised in clearings in the lower forest, and used chiefly in time of famine. Ornamental aroids of many genera are now abundant in Honolulu gardens, but these are strictly exotic, and none of these are naturalized. Another group that one naturally associates with a tropical background is the Begoniaceae, and yet of the 400 species, only one is native to the Hawaiian Archipelago. Our lone species is endemic, and is so distinct from its relatives that it has been placed in a monotypic genus, Hillebrandia. It is a beautiful plant with ornamental foliage and fine showy clusters of pink flowers, but is limited to such isolated and difficult regions ret few people, either natives or whites, have seen it. Lobelias Gagne the crowning pinky of our flora are the arbo- rescent lobelias. These constitute one of the unique elements of the Hawaiian forest flora, and aggregate some too species, dis- tributed among 6 genera, 5 of which are endemic. As RocK” succinctly states, ‘nowhere in the world does this tribe reach such : a wonderful Heres in such a comparatively small area.’ t families a ThA Ge eh. oS : comapeiang the Hawaiian land Siva ‘Many of the | species show aliz zation. The extraordinary Mae of variation S tionary impetus of ‘this ae oe Sake 3 the a —— lobelias ecenonss on | the continent, = of our: — 1917] MACCAUGHEY—HAWAIIAN FLORA 103 trees, and some reach the amazing height of 40 ft. Many species have a slender, naked, palmlike trunk, closely marked with con- spicuous leaf scars. This pole terminates in a large rosette of foliage and a showy inflorescence. These and other characters give the plant a deceptively primitive aspect. The Hawaiian genera are Brighamia, endemic, 1 species; Lobelia, 5 endemic species; Clermontia, endemic, 17 species; Rollandia, endemic, 6 species; Delissea, endemic, 7 species; Cyanea, endemic, about 45 species. There are many features, both struc- tural and ecological, which strongly suggest that our lobelias are the remnants of a very ancient flora, a flora that has well nigh been obliterated by profound geological and climatic changes. It is significant to observe that the other islands of the Pacific are practically lacking in lobelias. Furthermore, in other parts of the world these plants are notably alpine in distribution. Many high mountains of the tropics and subtropics are marked by a lobeliaceous flora similar to that of our Hawaiian mountains. These and other facts in local phytogeography lean strongly toward the geological hypothesis that at one time these island mountains stood at a much higher level (perhaps thousands of feet higher) above the sea than at present. Under this theory the islands as they now stand are but the vesiee of a former exten land ordinary geographic distribution of the ‘Hawaiian arboreal mollusks. ne undoubtedly has an application to such phytogeographic problems — as are involved in weed attempt to elucidate ihe origin of pee Hawaiian lobelias.. . 104 BOTANICAL GAZETTE [AUGUST toa high degree by many of our species. As HILLEBRAND states, “‘the polymorphism of the Hawaiian cyrtandras is extraordinary; no single form extends over the whole group, and not many are common to more than one island. The variations affect every part of the plant, and branch out and intercross each other in manifold ways to such an extent that it is next to impossible to define exact limits of species.’”*® The evolutionary status of our species is closely analogous to that of the native lobelias. The species of Cyrtandra are largely confined to the humid regions; they are precinctive and extremely shade-tolerant. Many species are to be found only in the narrow-walled ravines and dimly lighted recesses of the rain forest. C. cordifolia Gaud., C. Pickeringii Gray, C. gracilis Hbd., C. Kahilii Wawra, C. grandi- flora Gaud., C. paludosa Gaud., C. latebrosa Hbd., and C. Lessoniana | Gaud. are representative Hawaiian species of this genus. Composites Spiind only to the lobelias in importance are the Composine. There are over 80 species, representing 29 genera; of these , 60 species are distributed among 9 endemic genera. Several of the genera (Argyroxiphium, Wilkesia, Hesperomannia, and Remya) show “Many evidences of | isolated and specialized evolution and, as. HILLEBRAND rema probably belong to the oldest denizens of — our islands, a sepotition countenanced by the fact that each — holds no more than two species.” With reference to the last statement it must be remarked that several new forms in these a probably of specific rank, have recently been discovered. _ A number of these peculiar Compositae (Artemisia, Dubautia, _ Raillardia) are arborescent, and alpine in habitat. On the ee : _ mountains of Maui and Hawaii ii they reach an elevation of moe 1917] | MACCAUGHEY—HAWAIIAN FLORA 105 densely covered with shining silvery pubescence; from this body arises a tall inflorescence (6-8 ft.) of showy purple flowers. This unique herbaceous perennial is xerophytic, and occurs only at high elevations on Maui and Hawaii. Lipochaeta, Coreopsis, and Tetramolopium are large genera of herbaceous or semiligneous perennials; there are 10 or 12 species in each genus, mostly endemic. The flowers are small, but very numerous, and form showy masses of rich yellow. Bidens, Agera- tum, Xanthium, Sonchus, Vernonia, Erigeron, Gnaphalium, Fran- seria, Eclipta, and Centaurea are common weeds of the roadsides and fields. Modern research in ornithology has demonstrated the existence of several bird migration routes from South America to the north via Hawaii. The Hawaiian goose and the Pacific golden plover furnish specific instances of these long over-sea migrations. Inas- much as a number of the endemic composites show close affinity with certain Andean and other South American species, it is highly probable that they were carried thither by migrating birds.” A number of other native plants were probably brought by the same agencies, for example, Rubus, several endemic species, closely related to Pacific Coast forms; Nertera depressa, with fleshy red drupes, a South Pacific Coast species; Fragaria chilensis, which also occurs along Pacific America; Dodonea viscosa, with - : : glutinous capsules, and widely a o sndtcemee, es and others. : : The vast family Leguminosae, rivaled in size and distsibasion oS only ae the Compositae, i is abundantly represe ee oe Sophora, tetany anit: a rina, are arbo _ ‘ies occur in dae Canavalia, Vigna, ee 106 BOTANICAL GAZETTE [AUGUST trees of Cassia, Poinciana, Peltophorum, Pithecolobium, and allied genera.”* A number of the indigenous legumes are beautiful, high- climbing woodland vines, with showy clusters of bright colored flowers; Syrongylodon lucidum, Vicia Mensziesii, Mucuna urens, Dioclea violacea, and Canavalia galeata are examples of these. Species of Crotalaria, Indigofera, Leucaena, Acacia, Mimosa, Dolichos, Medicago, Phaseolus, and Desmodium are common road- side weeds. The most valuable and widely known of our cabinet woods, koa, is from the common forest tree Acacia koa. Rubiaceae The Rubiaceae comprise a large and diversified portion of our flora. There are 13 genera, of which 4 (Kadua, Gouldia, Bobea, and Straussia) are endemic. There are between 50 and 60 rubia- ceous species; of these the majority are tall shrubs or arborescent. The other genera (Gardenia, Plectronia, Coffea, Morinda, Psychotria, Paederia, Nertera, Coprosma, and Richardsonia) occur in many other tropical regions. — Of special interest, because of their beautiful flowers, are the __ two endemic species of Gardenia. The blossoms are large, white, _ deliciously fragrant, and rank high among the wild flowers of Hawaii. The coffee (C. arabica) was introduced in 1823, and its cultivation spread rapidly to all of the larger islands of the group. Although a combination of economic and cultural factors has 7 suppressed the coffee industry, the plant itself is thoroughly , and occurs in many of the humid lower regions. ; Birds have eeeitedy snsted mi dis eminati ao ae "hated trees and shrubs comprise a. ‘conspicuous and abun- ae dant element in the native forests. Th oS 1917] MaACCAUGHEY—HAWAIIAN FLORA 107 species. Two of the three genera (Pelea and Platydesma) are endemic; the third (Zanthoxylum) is world wide in its range. Pelea, named in honor of the Hawaiian volcano goddess Pele, is a large genus, with nearly 30 recognized species and an even larger number of varieties. Like the species of Cyrtandra and the lobeli- aceous genera, the species of Pelea are highly variable, with many intergrading forms, so that as yet the species are poorly defined. Platydesma is an isolated genus, with 4 woody species. Zan- thoxylum has 7 species, 6 arborescent, and many varieties. The majority of these are characteristic of arid leeward regions and old. lava flows. There are no native citrus fruits, although the orange has become naturalized in many districts, particularly in the Kona district, on Hawaii. | Violaceae The endemic Violaceae are a distinct surprise to the mainland botanist on his first excursions in our Hawaiian forests. Instead of tender little herbs, he finds stout woody shrubs, ranging in height from 3 to 6 ft. The flowers are quite like those of the familiar eastern violets, and are white, pink, purple, or blue in — color, according to species. There : are a or 8 species, ranging in swamps, they cover r et ns der- have ca aber : = possibilities in the way of ceatvated v violet bushes. ne and : suggest novel horti- 108 BOTANICAL GAZETTE [AUGUST It is probable that Hawaii originally received. its contribution from the Malayan center, although its 4 genera are now almost wholly endemic. All of the 13 or more Hawaiian species are endemic, and of these a number are sharply localized in their range. The 4 genera are represented as follows: Tetraplasandra, 7 spp.; Reynoldsia, 1 sp.; Plerotropia, 3 spp.; Cheirodendron, 2 spp. The charac- teristic American-Asiatic genera Aralia and Panax do not occur in Hawaii. Labiatae The Labiatae are represented by 7 genera. Three (Sienogyne with 16 to 18 species, Phyllostegia with about 20 species, and Haplostachys with 3 species) are endemic. Plectranthus comes from Australia, and Sphacele from the Pacific Coast of America. The two remaining genera (Salvia and Siachys) are weeds of world- wide geographic range. Hawaii has no equivalent be the familiar mints of eastern fields and waysides, such as catnip, peppermint, pennyroyal, hoarhound, and a score of others. Our Sphacele hastata, endemic from an Andean genus, is a typical example of precinctiveness. It forms an extensive belt around the great volcanic mountain Hale-a-ka-la at an elevation of about 3000 ft., and occurs nowhere : else in the archipelago. Many of the shrubby species sof - Phyllostegia and Stenogyne have lovely masses of flowers, white, pink, and red, and give beautiful color effects against the dark greens of the rain forest and the wet — jungles which they inhabit.” Malvaceae” “The Malvaceae constitute a large family. : Se oe exept hee arctic regions, md iad eed _ _ the tropics pics. Hawaii is well endowed with this — : ae group. "There ¢ are 2 endemic genera: Kokia, the Hawaiian free cotton, with 2 species; — a apecien.. All of ae 1917] : MacCAUGHEY—HAWAIIAN FLORA ~ r09 The large genus Hibiscus has 6 or 7 native species, all shrubs or trees, with large flowers of striking beauty. The blossoms are white, pink, red, or yellow, according to species, and form a dis- tinctive feature of the rain forest. The cosmopolitan genera Malva, Malvastrum, Sida, and A butilon are common on the semiarid lowlands. Gossypium, the true cot- ton, includes the unique Hawaiian cotton, G. tomenlosum, a spread- ing shrub, endemic, densely covered with white tomentum, and growing in arid situations along the coasts. Solanaceae Of the 70 genera of this family, only 3 (Solanum, Nothocestrum, and Lycium) comprise elements in our native flora. There are many introduced Solanaceae (Physalis, Datura, Nicotiana, etc.), some brought in at a very early period and now thoroughly established. The genus Solanum has 6 endemic species, one arborescent; in addition to these there are a number of weeds belonging to this genus. Nothocestrum is an endemic genus of 4 arborescent species, and is closely related to the Brazilian genus Athenaea. Lycium, a genus of 70 species, is represented in our flora by a single widely distributed littoral anaes ride although there are a number of endemic species. | ‘Some - of the more important genera, from the st listribution and number of species, are Bromus, Calamagrostis, Cenchrus, 8 phobia Prank Scag pera Dactylis, ees con as stuc so IIo BOTANICAL GAZETTE |AUGUST The representation of Cyperaceae is roughly as follows: Cyperus 17 spp., Kyllingia 1, Fimbristylis 4, Eleocharis 1, Scirpus 2, Hypo- lytrum 1, Rhynchospora 4, Cladium 1, Baumea 1, Vincentia 1, Gahnia 5, Oreobolus 1, Scleria 1, Uncinia 1, Carex 5. Absent pests Hawaii is entirely free from any plants poisonous to the touch. To the botanist familiar with the distressing prevalence of these pernicious vines and shrubs in the continental woodlands, it is a relief to work one’s way through a Hawaiian jungle with the certainty of complete safety in this regard. Neither are there any stinging nettles. Mucuna urens, the well known “cow-itch” plant, whose pods are covered with stinging hairs, is naturalized _ in certain restricted areas on the islands of Maui and Hawaii. The Anacardiaceae are represented in Hawaii by a single arborescent Asiatic Rhus (R. semialata Murray var. sandwicensis Engler). This species extends from India and the Orient to Hawaii, and is non-poisonous. Our variety is a small tree, growing in isolated clumps in all the islands. It is to be hoped that the pernicious T. vernix, T. Siaoes and T. Toxicodendron of North America may never by any accident reach Hawaii. The noisome Paederia foetida was accidentally introduced a number of years ago, and its seeds, like those of Rhus Toxicodendron, are abundantly distributed by birds. It ‘is now a pest in many ofthe valley, as it smothers all other ni amene : : : “Fems Tees) genera and 185 species pte ophy a 2 genera ae : " E : oe 75 eek cent and over of endemic speci - 1917] MACCAUGHEY—HAWAIIAN FLORA go 9 from the arid raw lava flows to the most humid portions of the jungle forest. A number of species (Cibotium and Sadleria) attain arborescent stature (8-35 ft.) and many others are of large size.3_ The other extreme is found in the minute Hymenophyl- laceae. These are abundant in the rain forest, and clothe the trees with their filmy fronds. There are about 22 genera of true ferns. The largest of these are Asplenium, 40 spp.; Dryopteris, 21; Polypodium 14, Elapho- glossum 8, Diellia and Athyrium 6, Sadleria 5, Trichomanes 4. The number of species in the larger genera, and in some of the smaller as well, must be stated as approximations, as many of these species are in serious need of revision. Many of the forms hitherto described as varieties will undoubtedly be raised to specific rank upon careful investigation, and numerous specific wap tain require redefinition. Some of the abundant forms not indicated by the generic list are Marattia Douglasii, Gleichenia spp., Gymnogramme javanica, Vittaria elongata, Nephrolepis make Cystopteris Douglasii Doodya media, Odontoloma repens, Micropelia spp., Schisostegia c Lydgatei, Pellaea ternifolia, and Adiantum spp. These are sae of genera represented by only a few species. Salviniaceae are represented by a peceatly ssaroduved Asolla; a. _ Marsileaceae by 2 endemic species of Marsilea; -Equisetales are not represented. The Lyco Hodiale es have 3 genera in the foes: Lycopodium with to spp. and 5 endemic; Psilotum with 20 widely ae distributed species; and ror agpe sigied 3 endemic and I other : < species. About 5 5° of the F Wawan RAT taal shame 25 ue ha and t pee spe jes Ii2 BOTANICAL GAZET TE [AUGUST habitats of many mosses, which completely cover the water- saturated ground of large areas, and mask the treacherous quagmire.* The liverworts, including the Marchantiales, Antho- cerotales, and Jungermanniales, are abundant in the humid regions, many species being epiphytic and epiphyllous. Species of Marchantia, Anthoceros, and related genera are conspicuous along streamways and in other moist places. Fungi The larger fungi are conspicuously absent from the woodlands. There are a few woody brackets, a few dull-colored mushrooms, a few puffballs and trembling fungi. The sum total of all these is insignificant, however, when compared with the rich fungus flora of such.a region as the eastern United States. One may gather more fleshy fungi in a day’s collecting in New York, for example, than he would find in diligently scouring our forests for a week. This condition is somewhat surprising, as the cool, humid rain forest zone, with its abundance of decaying vegetation, would appear to be favorable for the development of the fleshy fungi. A number of species of slime molds occur in the ravines and jungles. It is to be regretted that no comprehensive study of the Hawaiian fungi has been made.*5 Lichens are abundant in all parts of the islands. They com- _ prise the first invaders of the freshly cooled lava flows. They -Juxuriate in the cool humidity of the rain forest and the summit bogs. They cover the exposed cliffs and ledges of the middle zones, and withstand the aridity of the leeward lowlands and of the high mountains (6000-14,000 ft.). The lichen flora not only _ occupies a wide variety of ecological areas, but furthermore is Ls of considerable richness. No comprehensive statement can be a and species, as the Haves venir: have never : ay received exhaustive study. : tropes a Beology 35 24-30. te 1917] MacCAUGHEY—HAWAIIAN FLORA 113 Aboriginal introductions Any outline of the Hawaiian flora would be seriously defective that did not give prominence to the numerous plant introductions by the primitive Hawaiians in their migrations from Samoa and the South Seas. Carefully gathered historical evidence has established the fact that during a long period of time, probably several centuries, the ancient Hawaiians maintained intercourse with their kinfolk in the South Pacific, making the long voyages in their splendid canoes. During this eventful period of migration and intercourse with the south, about 25 species of useful plants were consciously introduced by the natives, and perhaps a much larger number unconsciously brought in as seeds and spores. The list includes :° *Colocasia esculenta; the taro; starchy corms used for food. Ipomoea Batatas; sweet potato; many native varieties. *Musa sapientum banana; many native varieties. ocarpus incisa; breadfruit tree; *Cocos nucifera; cocoanut palm; formerly ony common. *Dioscorea sativa; yam; starchy tubers; climbing vine. *Dioscorea i yam; starchy tubers; climbing vine. *Alocasia n II4 BOTANICAL GAZETTE [AUGUST The starred names indicate species that have escaped from cultivation. Many of these have become so thoroughly naturalized © and established in the lower forests, on the lowlands, and along the beaches that they are easily confused with the true i ae ahs flora. The oe importation of this diversified series of edible, fiber-p , oil-producing, and other useful plants, from lands so remote, and by methods so primitive, betokens native, horti- cultural skill of no mean importance. As stated by LypGarTE, *“‘the successful introduction, perhaps acclimatization even, must have meant repeated voyages, extending over generations or even centuries. And not time alone, but patience and skill must have been required for the successful introduction of a seedless tree like the breadfruit. Under favorable conditions it is not easy to propagate; exposed to the trying vicissitudes of a long canoe voyage, weeks of wind gin weather and open sea, lack of water, burning sun and blighting spray, huddled into the bottom of the shallow canoe, how many, many failures there must have been.” In conclusion, it may be pertinent to suggest that there is an unwritten chapter in the history of Hawaii’s introduced flora, — namely the introductions possibly made by the early Spanish explorers. They undoubtedly visited the islands repeatedly, long — _ before the discovery by Coox’?; there are numerous evidences of their intercourse with the natives, and it is not all beyond the realm of probability that some of the plants now thoroughly sparse were brought & in by these early escent i waiian Islands ds were — ed ‘Spaniard in November, a In ee ov a 2 200 years bef IE it ee ae See THE GAMETOPHYTES OF TAXUS CANADENSIS MARSH CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 234 — A. W. DUPLER (WITH PLATES XI-XIV) Introduction While the European Taxus baccata L. has been studied by a. number of workers and its morphology is quite well known, up to the present time no accounts have been published dealing in any connected way with the morphology of the American form, Taxus canadensis Marsh., records having been made of only a few scat- tered observations. Although by some, including PitcER (7) in ENGLER’s Das Pflanzenreich, T. canadensis is considered as merely a subspecies of T. baccata, it has seemed worth while to investigate its morphology and compare it with other forms, and especially with the results obtained in the study of T. baccata, most of the work in which was done a number of years ago. The present paper gives” es : an account of the male and female gametophytes in connection ; oe with Bsaed Mieneadl — i a —. wit Wa ‘Whe miatedal want in the chad ins collected dur ng t of a peso don, P 116 BOTANICAL GAZETTE [aucusT Historical Taxus baccata has long been a favorite form for study, the ovule and the seed first attracting attention, and the early work, therefore, relating almost exclusively to these features. The first study of any ~ importance relating to the gametophytes was that of HorMEIsTER (x1), who reported some of the more obvious features of both the male and female gametophytes. The history of the male gameto- phyte has become further known through the work of BELAJEFF (3), STRASBURGER (4), and JAGER (6). Miss Ropertson (18) made some observations, but, in her own words, her “‘results on the whole simply confirmed previous work.’’ CoxKER (g) studied the micro- spores in T. baccata and several of its varieties. STRASBURGER’S early work had to do more especially with the ovulate shoot and the ovule, but in 1879 (2) he described the origin of the megaspore mother cells from the hypodermal layer of the nucellus and gave a few observations on the development of the female gametophyte. The best accounts of the female gametophyte are by JAGER (6), _ who gave a rather complete description from the megaspore to the mature endosperm, and by StTrasBuRGER (12), who gave attention particularly to the early stages, especially to the forma- tion of the megaspores and the free nuclear situation. COKER (9) _ also studied the megaspores. : In T. canadensis itself very little work: has been reported. : HoFMEISTER (r) has a note concerning the proembryo; CHAMBER- LAIN (5) studied the condition of the microsporangium at the ae of October; CoKER (9) reports “more than one embryo 8 . . . not uncommon in Taxus ¢ lensis”’; and THOMSON : Ge) tas ted he conto of the megaspore menbrane ae | _ Male gametophyte — ae 3 CHAMBERLAIN (5) in material of T. ¢ nade is a a en collected i in n the Chicago — October + eh found the i ig math. : : eS Leos as s the winter condition. : . Matec a cells” divided, in 1904, during w 1917] DUPLER—TAXUS CANADENSIS Ei7 sporangium develops during the summer, and by the time men- tioned the microspores are forming (figs. 2-12). In a single strobilus all stages from spore mother cells to completed tetrads _may be found. Different stages are also found in a single sporan- gium, although here the range is not so great as in case of the entire strobilus. Reduction in the chromosome number and the formation of microspores take place as the result of the usual two divisions of the mother cell. The first division (figs. 2-5) results in two hemispherical cells, and this is followed by the second division (figs. 6, 7), usually in the same plane, resulting in the bilateral tetrad of microspores, although the two planes of division may sometimes be.at right angles to one another. Sometimes the second divisions are not simultaneous (fig. 8). Further divisions may also occur, resulting in the formation of more than 4 microspores from a single mother cell, as many as 6 having been found (figs. 9-12). The microspores soon separate from one another and become surrounded by moderately heavy spore coats (fig. 13), the tapetum remaining quite prominent and showing little signs of disintegration even at this time. The microspore stage is the winter condition of the microsporangium, the only noticeable change in the microspores. between this and pollination being an increase in size (figs. 13, 14). : , This growth takes place in the early spring, during the period in which the strobilus i from the winter scales and piaene its mature size (about the middle of April). Torreya californica in England (10) and T. peti in : - Florida (14) pass the winter in the mother cell condition. STRas- BURGER (12) reports that in Taxus baccata the “pollen” mother : : ay So far as fal gies T. ‘canadensis is is ; the only one of the : 118 BOTANICAL GAZETTE [AUGUST 17) are binucleate when shed, the microspore having divided into the tube and generative cells while in the microsporangium. The absence of prothallial cells is a feature common to the Taxineae, Taxodineae, and Cupressineae. POLLINATION.—In the spring of 1914, in the vicinity of Hunting- don, Pennsylvania, pollination was first noted April 23. No strobili were found shedding pollen on April 20, but 3 days later pollen was being shed abundantly, especially in the more exposed situations, and most of the ovules collected at that time contain — pollen grains. JAGER (6), at Zurich, reports the beginning or middle of March as the time for the pollination of T. baccata. The pollen grains are wind scattered and are formed in great abundance, while the frequent occurrence of both staminate and ovulate strobili on the same shoot increases the chances for pollination. In the material which I have examined there were very few ovules which had not been pollinated, and sometimes quite abundantly, as is evidenced by the frequency of several pollen tubes in an ovule. The pollen is caught by the small pollination droplet which protrudes from the micropyle of the ovule and is drawn into the yeas ey the concentration of the - droplet. | - Inthe ovule the pollen grains are found 1 sf the . — nucellus. While no definite pollen. chamber is ; formed, the outer- : ‘most cells of the nucellus begin to disintegrate about the time of pollination, resulting in a ragged edge to the sonaicae on which the _ pollen grains become lodged. a POLLEN TUBE.—The pollen grain, oe on the nucellus, soon . begins to elongate, the exine is ruptured, and the intine grows | out to form the tube. The young tube soon penetr ellus, gO : = once started, ‘invades: ‘the tissue very rapidly. ‘Within ae te while others ~ not E have » penetrated s so a there being 1917] DUPLER—TAXUS CANADENSIS 119 nearer its margins, in some cases reaching close to the edge of the nucellus (fig. 27). During the elongation of the tube there is also considerable increase in diameter, such that by the time the tube has reached the female gametophyte region its diameter is several times greater than at first (fig. 22). A striking enlargement now takes place. If the female gametophyte still consists of free nuclei, as it frequently does at this time, it may be so crowded upon by the enlarging tube as to be pushed to one side; or the megaspore membrane may remain quite firm, retaining its shape, the tube then being forced to-conform its shape to that of the resisting meg: membrane (fig. 28). A number of cases of branching tubes ¥ were found, the nuclear contents in such cases being near the point of branching, while the branches generally have dense cytoplasmic contents, indicating their haustorial activity. The enlarging tube usually spreads itself over the micropylar end of the female game- tophyte; it may go off to one side and penetrate far into the nucellus; or it may grow along the side of the endosperm, passing by the archegonia i in ‘the micnopyier end neil the endosperm. hes turn f. yw if usually enlarges between them, while i * some ¢ cases the pollen tube may entirely pass the developing fe: phyte and enl o below it. It seems that in a oe female g te tap ei developing from an upper megaspore (fig. 31). Ce In case the nucellus is is inv d by a number take they a produce a rather int tic ‘The female gametophyte - is crowded upon fron reer’ sides cud i fi 1 quite out of its normal shape. A case was s found of ar 120 BOTANICAL GAZETTE {AUGUST their enlargement and crowding upon one another produces such a complex that it is practically impossible to count the tubes except by their nuclear contents. The tubes which are on the periphery of the complex may be so crowded by the more interior ones as to remain quite narrow and their contained body cells may even be flattened by the pressure. The cytoplasmic contents of the tube become quite vacuolated early in the growth of the tube and in early stages contain a large number of starch grains, although these apparently disappear in the later stages. The cytoplasm is always more abundant near the growing end of the tube, but when the tube enlarges at the forward end the bulk of the cytoplasm remains more or less closely connected with the nuclei of the male gametophyte. Frequently in late stages the cytoplasm may contain accumulated masses, irregular in shape and densely staining, and these may even be discharged into the egg cytoplasm at the time of fertilization. : DEVELOPMENT OF MALE GAMETOPHYTE.—Soon after pollination the microspore begins to elongate, and the first division into tube and generative cells takes place within 10-12 days after pollination (fig. 16). This division results in two unequal cells (fig. 17), the smaller generative cell being held in the base of the grain by a _ plasma membrane, while the larger tube cell forms the elongating tube. The division of nuclear material is no doubt equal, but the tube cell nucleus soon becomes larger than the nucleus of the generative cell, the former becoming ellipsoid and retaining this shape tk the inder of its history. The cytoplasm of the generative cell is denser eG — of ihe tube cell. : ' As! ee aes, a 7. re ak : » the grow- a ing end, migrating rapidly be behind the tip of the tube ey iG, Os oe EB yen before the ‘generative coll divides, the tube cell nucleus has” usually gone some distance into the tube. The generative c sl ae : . enlarges, pushes out its tim ting _ found together in the basal par t9t7] DUPLER—TAXUS CANADENSIS 121 The body cell soon migrates into the tube and is followed by the stalk cell nucleus, the two usually being in contact and appar- ently having passed into the tube together. During the growth of the tube through the nucellus, up to the time when the pollen tube reaches the female gametophyte, the 3 nuclei are in an axial row, while later the stalk nucleus migrates around the body cell and es a position besides the tube nucleus. Of these two nuclei in the tube, the tube nucleus is generally to be recognized by its being slightly larger than the stalk nucleus. The body cell begins enlarg- ing at once after entering the tube. As it passes down the tube it is slightly ellipsoid, but on reaching the end of the tube, as the latter is enlarging about the endosperm, it becomes rounded as it increases in size. The cytoplasm remains dense and the nucleus becomes large. During the early history of the body cell its cyto- plasm is uniformly Soneented through the cell, but : as it reaches Teo wake pet vn laonn Kaenrrow Lass Ps and here eae delicate radial strands (fig. 23). "The nucleus, which earlier occupied a central position, takes a more peripheral one (usually on the side opposite to that on which the stalk and tube nuclei lie), while the cytoplasm becomes considerably vacuo- lated along the margin of the cell, he eRe Sinner peering _ with the increased vacuolization. . The division of the body cell into the two male cells takes place : shortly before fertilization. Several mitot n were found. — _ The nucleus of the body cell being at one side of the _ cell, there is an unequal division of the cytoplasmic material. ae _A broad spindle is formed and the cell plate laid down on it is 2 the ¢ lenticular i in outline, resulting i in the. formati 122 BOTANICAL GAZETTE [AUGUST investment of the smaller nucleus. He speaks of “‘male nuclei’’ and not of male cells. His figure shows two nuclei in a common cytoplasmic mass. STRASBURGER (4) and JAGER (6) both recog- nized two “cells.” Miss RoBERTSON (18) figures the division of the body cell, but no cell plate is shown on the spindle, even in the late telophase; while her figure of the completed division lacks clearness on this point, owing to a possible inaccuracy in drawing or in technique. In her discussion she speaks of a “functional male nucleus” and “‘inequality of the sperm nuclei.” By the time the two male cells are formed, the vacuolization along the margin of the larger cell has become quite pronounced | (fig. 26), and this continues until finally the cytoplasm has prac- tically all withdrawn from the plasma membrane and collected about the nucleus. In this condition the male gametophyte has reached its maturity and fertilization may now take place. Should male cells fail to function in fertilizing an egg, as is frequently the case where there are a number of tubes in an ovule, they remain in this condition for a time and then disintegrate. Male cells have been found in ovules in which th yo was iderably advanced. Two unequal male cells are ae for Torreya taxifolia (14) and Cephalotaxus Fortunei (16), and the division of the body cell into male nuclei in C. drupacea (17). Miss RoBertson concludes that there are formed ‘‘a functional male nucleus” and a ‘“‘smaller male nucleus” in T. californica (18). In an earlier account (11) she had stated that the body cell divided into two nuclei of _ equal size. There is evident among the Taxineae a tendency toward the elimination of male cells in the formation of the so- called “male nuclei” only. The inequality of these nuclei or cells is another advance. A mere cutting off of the smaller nucleus © os from the body cell would be — = wie the final one, not - - cell functioning asa male cell... ~* Tatas the : male gametophyte : wt ie aes consists of the stalk and tube nuclei and the = two male « This is ae ine comps 1917] - DUPLER—TAXUS CANADENSIS 123 division between the microspore and the cells functioning in fertilization. Female gametophyte MEGASPORES.—STRASBURGER (2) long ago pointed out that in Taxus baccata the megaspore mother cells are the end cells of a series arising from the hypodermal layer of the nucellus, and that they are clearly distinguished from the surrounding cells by their larger size and larger nuclei. The same situation seems to hold for T. canadensis. STRASBURGER (2) claimed several megaspore mother cells; JAGER (6) agrees with him, but CoxKER (9) in his study of T. baccata states that there is no evidence that more than one megaspore is ever formed. He says ‘‘the mother cell is hard to distinguish. At the time of its first division it is long and > narrow, resembling very closely the cells adjoining.” As to the number of mother cells, STRASBURGER was probably right. In my preparations I have found no difficulty in recognizing the megaspore mother ‘cells, nor does there seem to be any doubt that there may be a number of them in an tee Only one, or occa-_ sionally two, may function, but other megaspore mother cells may be present, by all the other tests of a saatlies tt The mother cells — are distinguished from the other cells of the nucellus, not only by | their size and the size of their nuclei, but by their different staining reaction. The group of mother cells may be recognized in the autumn or winter (fig. 33). The occurrence of two linear tetrads _ of megaspores (fig. 38) is sufficient evidence that there have been at _ least two megaspore mother cells in the case figured. — STRASBURGER (12) and CoxEr (g) have given rather euiples : descriptions of megaspore formation in Taxus baccata, and the : Process is essentially the same in T. canadensis, so far as my prep- arations show (figs. 338). In r. saccola the second division a is said to he ci 124 BOTANICAL GAZETTE [AUGUST STRASBURGER (12) states that the starch soon disappears from the megaspore mother cells of T. baccata, but COKER (g) in his figures shows starch grains in the megaspores as well as in the megaspore mother cells. The starch is not confined to the megaspore region, but is found abundantly in the adjoining cells, and some of it occurs throughout a considerable portion of the nucellus in T. canadensis. The method of formation of a tapetum about the megaspore mother cells, as pointed out by STRASBURGER (12) in T. baccata, also holds for T. canadensis. ‘These cells are formed more or less obliquely to the long axis of the megaspore cells (fig. 34), are rich in content, and stain differently from the megaspore mother cells. THOMSON (15) speaks of the tapetum derived from the nucellus as a “secondary tapetum,” in distinction from forms in which the tapetum is derived from the sporogenous tissue, in which case it is called a ‘‘primary tapetum.” GOEBEL pointed out long ago, how- ever, that the significance of the “‘tapetum”’ is physiological, and not morphological, and that it may have a variety of origins. The megaspore mother cell seems to be the usual winter condition. _ While SrrAsBURGER (12) says the megaspore mother cells of T. baccata are completed in October and that further development takes place the next spring, this does not always hold for T. cana- densis, as I have found young female gametophytes of several free nuclei in some of the material collected in November, 1913. Most of the ovules taken at this time showed the mother cell condition, but even in some of the ovules collected as late as December it ‘may be doubted whether the megaspore mother cells had become fully matured. Evidently, therefore, the time for the maturity of the megaspore mother cells and the formation of megaspores may © | __-vary, yet the general statement may be made that the mother oh ie the usual winter condition and that megaspore formation _ me - bani de takes ~ in the pone with the renewal of the growing = 1917] DUPLER—TAXUS CANADENSIS 125 the formation of young female gametophytes (figs. 39-44). The further development of several megaspores will be described later. Some interesting cases were found, such as those in which one of the upper megaspores had evidently functioned, while the lower ones had failed to develop, although still recognizable (figs. 30, 31). In both cases figured the pollen tubes have pushed past the gameto- phytes and penetrated to the central region of the nucellus. THomson (15) in his investigation covering the megaspore membrane situation in the gymnosperms reports that in Taxus canadensis the megaspore membrane, while recognizable in the early free nuclear stages of the gametophyte, is practically unrecog- _ nizable in later stages. This agrees with my observations that the membrane is quite firm about the young female gametophyte, but seemingly fails to develop with the endosperm and is soon lost sight of. THOMSON associates this with the absence of the ‘primary tapetum”’ and regards it as a specialized advanced character, indi- cating that the Taxineae are “recent”’ as compared with some other forms. DEVELOPMENT OF FEMALE GAMETOPHYTE Free nuclear stage—The first division of the functional sae : Spores takes place soon after their formation, and other divisions, which are always simultaneous, follow in rapid succession (figs. ‘ 45,46). Th ; as the number of nuclei increases. . : At first the nuclei are scattered i in the embryo sac, but as this increases in si lated in the center, the cytoplasm — with the nuclei dies alleg 6 paiphaeal position, —— 126 BOTANICAL GAZETTE [AUGUST are developing, one grows upward, the other downward (fig. 51). In the early stages the embryo sac is usually pear-shaped, the narrow portion marking the original position of the megaspores, while the expanded portion shows the region of growth (figs. 47, 51). The growth of the embryo sac and the enlargement of the endosperm after walls have been formed crowd upon the adjoining cells of the nucellus in such.a way as to distort and flatten them, while no doubt some of the nucellar tissue is also digested by the growing gametophyte. Wall formation and growth of endosperm.—The first formation of walls between the nuclei results in a single layer of cells sur- rounding the central cavity (fig. 50). The cells at this stage are rich in starch, the starch grains having also been present during the -free nuclear stages. Centripetal growth of these cells then begins by the radial lengthening of their walls, the walls reaching the center and forming a completely closed tissue before further cell division takes place. Several cases were found showing this feature in various stages, but in no case had periclinal walls formed before the tissue was closed (fig. 51). Cells which in a single section appear to be internal are merely the inner ends of cells abutting the margin in other sections. At the very narrow upper end the cells are very closely crowded together. JAcER’s account (6) of the formation of the endosperm in Taxus baccata differs in a few details from this, in that he states “that the cavity is filled with tissue by the inward growth of a series of cells formed by periclinal walls. His technique was such, however, that he could easily have been mistaken in his interpre- tation of the situation. The filling of the central cavity by growth and periclinal divisions seems to be the rule among gymnosperms, and is probably to be correlated with the size of the cavity at the time wall formation begins. The smallness of the cavity in Taxus — _may account for the method of tissue formation found here. a Following the complete filling of the central cavity with cell : oo. _tissue, periclinal walls come in, giving rise to several layers of cells a between the margin and the center. Anticlinal divisions also take - place soon and the vow of the endosperm it ins alk d rections co aos cell divides into several neck cells, all in the tangential plane, ser serv- 1917] DUPLER—TAXUS CANADENSIS 127 Growth of the endosperm goes on rapidly, the greater meristematic activity being in the central portion, especially in the basal region. In the early history of the endosperm the cells are uninucleate, but as the embryo develops they become multinucleate, while in the central portion of the endosperm, below the growing tip of the embryo, the cells become elongated, forming a conducting tract for the food from the basal region of the ovule to the growing embryo. This elongation ceases to show after the embryo reaches maturity. In the mature endosperm, with the exception of the extreme micropylar portion, an abundance of food material is stored, this being the food supply of the seedling in the early stages of its germination. A comparison of the size of the endosperm at different times mn its development may be of interest. In fig. 52 there are shown 3 outline drawings, to the same scale, showing the comparative size of the endosperm at the time of wall formation (as in fig. 51), at the time of fertilization, and at the maturity of the seed. It is readily seen that the greatest growth of the endosperm takes place after fertilization. Archegonia.—The archegonium initial arises ba the outer- most layer of cells and is recognizable very shortly after periclinal — walls come in. The initials appear a short distance behind the “point” of the endosperm, but always occur in the micropylar end if the gametophyte is one which has developed from an inner — oS megaspore; in case of a gametophyte from an outer megaspore the archegonia will be on the side of the gametophyte toward the — center of the ovule. The initials can be recognized by their slightly larger size and by the size of their nuclei (fig. 53). The surrounding cells form the archegonial jacket. The initial divides into the — _ primary neck cell and the central cell (fig. 54). The primary yneck ng merely Il, a “neck” hardly being : = of the maturity. of the a are mere sane usually wi ith able. These neck cells become flattened, and by the time 128 BOTANICAL GAZETTE : [aucust ventral canal cell or nucleus, it may be regarded that this central cell is the functional egg. This agrees with Torreya taxifolia (14). In Cephalotaxus Fortunei (15) and C. drupacea (16) a ventral nucleus is formed, in the latter disorganizing before fertilization. ‘This marks the final elimination of the row of canal cells, an elimina- tion which has been such a persistent and gradual process from bryophytes through pteridophytes and gymnosperms. In the earlier stages of the archegonium the central cell nucleus is near the upper end of the cell, but as the archegonium matures it takes a more central position (fig. 55), the cytoplasm being some- what vacuolated and supplied with an abundance of food material, some of which stains quite darkly with the staining agents used. The archegonial jacket is recognizable from the initial to the. mature archegonium, but is not strikingly conspicuous as in some other forms, and less so in the mature condition than earlier. Usually there is a jacket about each archegonium, with several layers of cells between the archegonia, but it is not a rare thing to see two archegonia with only a single layer of jacket cells between them, and several cases were found in which two archegonia were surrounded by a common jacket, this latter condition being an ‘approach to the archegonium complex found in some of the other _ groups of gymnosperms. Several archegonia are usually present in a gametophyte, 4-8 being the average number. _ SUPERNUMERARY GAMETOPHYTES.—Mention has been ke of the fact that more than one megaspore may function. Hor-— MEISTER (1) long ago pointed out the presence of more than one embryo sac in Taxus baccata, and JAcER (6), STRASBURGER (22), and Miss ROBERTSON (18) have found the same situation. STRAS- _ BURGER ales oe usually one embryo sac develops; if more than 1; on several ‘tales he a Vii . ‘7 wee usually ee ce Sine : Wt 4 : * wel ¥ eral nuclei, the two embryo sacs usually lying beside one anoth * ee Mg S : : and. one case of one above the other. Coxer 2 (9) and Tuouson cs) a ; : : 1917] DUPLER—TAXUS CANADENSIS 129 two gametophytes, only the archegonia of the lower gametophyte, however, being fertilized In my material I find two gametophytes quite common, usually in an axial row, although sometimes lying side by side (fig. 57). One is usually larger than the other, the upper generally being the smaller of the two, and both may produce archegonia, as pointed out by Coker. Usually when 2 gametophytes develop in an axial row the pollen tubes push in between them, and then the archegonia are directed toward the tubes; but this is not always the case, as sometimes there are 2 apparently equally vigorous gametophytes, one above the other, and both with good archegonia in their micropylar ends. The pollen tube has spread out above the upper gametophyte, while the lower one is not in contact with the tube at any point in the case shown in fig. 58. Several instances of more than 2 gametophytes in an wre were found. One case (fig. 59) shows 3 gametophytes with tissue, the pollen tube lying between the two uppermost. No archegonia were present in the upper one, but both of the lower ones have good oe. pie of which has beer: fertilized and contains a pro- embryo. Other cases show hytes, in in one of which (fig. 60) 2 of the gametophytes have formed tissue, while the other 2 are in free nuclear condition, archegonia being present only in the lowest, which also contains a proembryo, the pollen tube in this: Pag a having pushed its way between the 4 gametophytes. — In - case (fig. 61) the ovule contains 3 g with tissue. ee archegonia, while the fourth one consists of only a few paeaart 3 and, although lying between two ‘vigorous gametophytes with tissue, retains its shape, evidently owing to the firmness of the megaspore membrane. One ovule was ; found containing 5 ere ae 130 BOTANICAL GAZETTE [AUGUST to which it may be suggested that there is an elongation of the nucellus during the growth of the gametophytes, together with a digestion of that portion of the nucellus immediately adjacent to them. The megaspores were evidently in contact when formed, but by the enlargement of the pollen tube between the young gametophytes they become widely separated as the tube develops. Fertilization While the fertilized egg represents a new phase in the life history and the account of it might be more properly included with that of the embryogeny, it may not be out of place to give a brief account of it in this connection. Ovules containing pro- embryos were found in material collected May 21. Preparations showing fertilization were found from this time on to as late as the middle of June, showing that the time for fertilization is not constant and may have considerable range. At the time of fertilization the neck of the archegonium becomes ruptured and the nuclear contents and part of the cytoplasmic contents of the tube are discharged into the egg. The egg nucleus has migrated to the basal portion of the egg; the male nucleus with its investing cytoplasm comes in contact with the egg nucleus; the _ cytoplasm of the male nucleus invests the two nuclei lying in con- tact and forms a dense sheath about them (fig. 56). With the _ fusion of the two nuclei the act of fertilization is complete. The behavior of the chromatin in fertilization could not be determined from i —— The cytoplasmic sheath about the two nuclei also in Torreya californica (11), T. taxifolia (14), and Cephalo- taxus : Fosteass (16) among the Taxaceae, as well as in several other cases reported, namely, by CoKEr (8) in Taxodium; by Lanp (13) i Ephedra; and poe NICHOLS (x9) in Juniperus communis var. | -— "The smaller male cell and the stalk and tube nuclei, together 2 peeomvesn hye ; oe hk we a a , when hen present, , -_* ryoorevenafter ae — —— _ may persist st for some time and _ - 2cog mz — t some Seige s of the p : 1917] DUPLER—TAXUS CANADENSIS 131 Time relations The time periods involved in the reproductive process are always of interest in the gymnosperms, as use is made of this feature in determining the primitive or modern character of a group, those having short periods being regarded as the more advanced in this respect. In my material the time from microspore formation to pollination was about 6.5 months; from pollination to fertiliza- tion may be as short as one month, although fertilization generally occurs after a longer interval, the time between pollination and fertilization having a considerable range, with an accompanying ~ range in the time of the maturity of the seed. I have collected mature seeds from the first week of July until late in September in central Pennsylvania. BELAJEFF (3) shows a pollen tube of Taxus baccata with two nuclei collected April 10 and a figure of fertilization dated May 26. JAGER (6), at Zurich, reports pollina- tion at the beginning or middle of March and fertilization at the end of May or beginning of June. Miss Ropertson (18) reports the time for fertilization at Kew to be about the middle of June. STRASBURGER (4) speaks of fertilization taking place the first half of July and the embryo complete by the end of August. None of these accounts gives so short a time period as l have found for T. canadensis. Summary Micissbor foceiation takes place i in the autumn. "There are no indications of prothallial cells. The pollen grain is uninucleate : when shed. a on wnt) Pan, ‘ SS ‘e J SD : Ss KI Ee) tes es x] 4 57 Io od! AY xs OS cer [7 ae a> 4g) Z ge 32 CTFz ee eebate or ASL a AP case eG gar, Recor age me ie 2H ee ee .> ARBORES FRUTICESQUE CHINENSES NOVI. IV CAMILLO SCHNEIDER (WITH PLATE XV) ) Salix (sect. SCLEROPHYLLAE Schn.) tenella, n. sp. (fig. A, ae. .—Frutex parvus squarrosus; .ramuli hornotini non visi, annotini biennesque floriferi obscure purpurascentes, minute puberuli vel fere tomentelli, dein glabrescentes, vetustiores cineras- centes vel cinereo-brunnei. Folia nondum satis evoluta anguste elliptico-lanceolata, apice obtusa, basi subrotundata, 11.5 cm. longa, o.2-0.4 cm. lata, superne viridia, initio plus minusve pu- berula, subtus discoloria, glaucescentia, sparse puberula vel ut videtur cito glabrescentia, nervis valde tenuibus utrinsecus circ. 6 superne incisis, margine integerrima; petioli 1-2 mm. longi, pilis subflavis tomentelli. Amenta tantum juvenilia feminea visa, coetanea, anguste cylindrica, 3-4 mm. crassa, ad 2.5 n. longa, pedunculis folia 3-6 Mest’ normalia Sproles puberulis Or | 5 mm. longis exclusis, rhachi t rotundae vel ovato-ellipticae, ovariis sublc : Auscae, : gi jones ae 2 esa : ao varia spare: isa soy brevissimo_ ad ain bifido eaten Pe stigmata brevia, biloba; | 2, ventralis late ovata vel — -ovato-rectangularis, dorsalis paullo 1 minor, similis similis vel 2 -partita. | aS Szechuan australis: in districtu Yen-yiian Hsien, Prope pagum Liu-ku, ae 138 BOTANICAL GAZETTE [AUGUST subdense albo-villosuli, deinde fuscescentes vel nigrescentes, glabrescentes vel subglabri; gemmae juveniles dense villosae. Folia satis magna, late elliptica vel elliptico-oblonga, apice subito breviter acuta, basi rotundata, rarius leviter subcordata, minora inferiora 6-8 cm. longa, 2-3 cm. lata, majora superiora g-12 cm. longa et 3.3—4.8 cm. lata, superne saturate viridia, adulta laxe (in costa densius) sericeo-villosula, subtus valde discoloria, pulcherrime albescentia, pruinosa (non papillosa), plus minusve (initio probabiliter dense) adpresse albo-sericeo-villosula, costa nervisque lateralibus utrinsecus circ. 8-12 angulo 50~-80° a costa divergentibus flavescentibus utroque latere prominentibus, reticulo nervillorum gracillimo prominulo, margine integerrima; petioli 6-15 mm. longi, undique dense villosi, superne late sulcati; stipulae ut videtur minimae, indistinctae. Amenta tantum fructifera visa, tardiva, ramulos foliatos 1.5-4 cm. longos terminantia, cylin- drica, ad 8 cm. longa et 1 cm. crassa, axi dense villosula. Flores adulti inter fructus remanentes circ. 6 mm. longi; ovaria ovato- oblonga, sessilia, dense albo-villosula; styli distincti circ. } ovarii - aequantes, ad basim bifidi, stigmatibus satis marcidis angustis _ oblongis bifidis brachiis styli fere aequilongis; glandula 1, ventralis, sicca ovato-trangularis, brevis; bracteae late ellipticae, apice rotundatae, pallidae vel brunnescentes utrinque villosae, ovario : subtriplo breviores. Fructus maturi circ. 7mm. oe ovariis _ adultis similes, ee Tr. ng lye 1, Pe fod m3 J lt. circ. 3400 Mm. : 30] er 4, € . Schneit (no 2059; tyP Ty A RO eet Schneider: qliestile oa biotite} = Unfortunately I collected only «few remnants of fruiting catkins, and I oo oiserayhiips - female flowers nor th ee a no doubt that this willow represents an excellent i ee 1917] SCHNEIDER—NEW CHINESE PLANTS 139 The name is given in honor of Professor BAyLEY BA.rour, the distin- guished Scotch botanist and director of the Royal Botanic Garden at Edin- burgh, which contains an extremely rich collection of living woody and herbaceous plants from China, especially from northwestern Yunnan. 119° Salix (sect. PstLostiGMATAE Schn.) Guebriantiana, n. sp. (fig. C, 1-5).—Frutex erectus, satis elongato-ramosus, ad 6 m. altus; ramuli novelli initio parce sericei, annotini biennesque glabri, rubro-fusci vel sordide brunnei; gemmae flavo-rubrae, oblongae, subglabrae. Folia juvenilia ovato-oblonga vel late lanceolata, apice sensim subacuminata, basi cuneata vel rotundata, 3-5 cm. longa et I-1.5 cm. lata, superne initio sericea vel sericeo-villosa, cito sub- glabra, intense viridia, subtus plus minusve dense sericeo-villosa, dein glabrescentia, discoloria, pruinosa, nervis lateralibus utrinsecus circ. 12 angulo acuto a costa divergentibus, margine integerrima vel saepissime versus apicem dense minute glanduloso-serrata, matura ignota; petioli vix 5 mm. longi, laxe sericei; stipulae dis- tinctae non visae. Amenta (mascula tantum visa) coetanea, anguste cylindrica, nondum satis evoluta ad 6.5 cm. longa et vix 7 mm. crassa, pedunculo ad 1 cm. longo folia 3-4 normalibus minora sed similia gerente excluso, axi laxe villosa; bracteae _ concolores pallidae. ves pe ebais brunnescentes, obovato- — tae, basi dorso. leviter saccatae, glabrae, filamentis ubduplo vel = fere 3plo breviores, quam glandula dorsalis subduplo 0 longiores; ee filamenta glabra, juvenilia satis crassa; antherae flavae, ovato- = globosae; glandulae 2, separatae, ventralis. lata, subquadrato- oe rotundata vel rectangularis et apice truncata, dorsalis illae vix vel ee - paulo brevior sed angustior, oblonga, apice truncata. | | ter urbem Yen-yiian Hsien et viculum Hun-ka, i hneids Soe? _. Acca ee do 140 BOTANICAL GAZETTE [AUGUST I take great pleasure in associating with this interesting willow the name of Mgr. pE GuEBRIANT, bishop of the famous French Catholic Mission at Ning-yiian-fu, in appreciation of valued service rendered to me while I was staying in that town during the month of April 1914. yer Salix (sect. PsittostiGMATAE Schn.) wolohoensis, n. sp. (fig. D, 1-5).—-Frutex erectus, squarrosus, ad 2 m. altus; ramuli, novelli tomentosuli, dein glabrescentes, olivaceo-brunnescentes, biennes glabri, fuscescentes; gemmae foliiferae ovatae, obtusae, adpressae, breviter pilosae, flavobrunneae, circ. 4mm. longae. Folia firma, etiam majora vix satis evoluta, late lanceolata vel anguste elliptico-lanceolata, apice sensim acuta vel minora sub- obtusa, basi late cuneata vel rotundata, minimis exceptis inferiora - 3-4m. longa et 1-1.5 cm. lata, superiora ad 7 cm. longa et 2 cm. lata, superne sordide viridia, initio densius dein laxe adpresse sericeo-villosa, costa flavescente plana, nervis lateralibus subincisis, subtus valde discoloria, initio tomento sericeo subflavescente dense tecta, dein argenteo-cinerea, adpresse sericeo-villosa (pilis costae _ parallelibus), costa nervisque lateralibus circ. 8-10 angulo 45-60" a costa 5s divereentibee: flavescentibus prominulis, rete nervillorum _ haud vel indistincte prominulo, margine integerrima vel obscure — _minutissime- distanter ‘glanduloso-denticulata; petioli 2-4 mm. eu u sulcati, t sti /minimae 2-3.5 mm. _ Jongae, semicordatae, glanduloso-denticulatae, ut folia pilosae. _ _ Amenta tantum fructifera visa, subsessilia, pleraque delapsa, ad 4 cm. longa et ad 8 mm. crassa, patentia, ad 4 nan 1 villosula, basi foliolis paucis parvis vix ad rom 1 4 pig nee satis similibus instructa; _ flores inter fructus 1 remanentes circ. Ss mm. Jongi; oval : ee a De} ~ 21 Paes = . ae - 4 1917] SCHNEIDER—NEW CHINESE PLANTS I4I Szechuan australis: inter oppida Yen-yiian Hsien et — in dume- tis inter pagos Wo-lo-ho et Hu-ma-ti, alt. circ. 2000-2400 m., 16 Junii, C. Schneider (no. 3490; typus in Herb. Arb. Arn. et Hb. Schneider; frutex squarrosus ad 2-metralis). This species much resembles S. psilostigma And., which I only know from the good specimens collected by A. Henry and G. Forrest in Yunnan and mentioned by me in the Pl. Wils. 3:116. From those the new species may be distinguished by its leaves being a little more hairy on the upper surface and not so thickly covered with a silvery silky pubescence on the lower one, by its much more glabrous bracts which are not densely silky outwardly, and by its shorter, entire, not deeply cleft styles. The fruiting catkins seem to be shorter in S. wolohensis. Without having seen the male plant, it seems impos- sible to determine the real relationship of this species, which comes from a region that has never been explored before by botanical collectors. Salix (probabiliter sect. DENTICULATAE Schn.) caloneura, n. sp. (fig. G, 1-6).—Frutex elatior, divaricatus; ramuli hornotini annotinique glabri, flavescentes vel olivacei, vetustiores rubro- brunnei, interdum ad gemmas adpressas puberuli. Folia elliptica, obovato-elliptica vel maxima late elliptico-oblonga, apice satis subito breviter acuta, basi obtusa vel subrotundata, interdum — subcuneata, Supers mntenge viridia, subtis valde discoloria, # & Ee ; ee i aat gities 2 ste ri is % ‘ y ag See : cee > nem -currentibus approximatis circ. a4 pro 1 cm. conspic ais, a nervillorum satis distincto, valde juvenilia subtus dist : | 142 BOTANICAL GAZETTE [AUGUST superantes. Fructus maturi circ. 6mm. longi, ovato-elliptici, glabri, ut ovaria pedicellati, pedicello glandulam siccam fere duplo superante. Szechuan australis: in districtu Hua-li ad flum. Yalung, in dumetis, alt. circ. 2800 m., 27 Maji 1914, C. Schneider (no. 1425; typus in Herb. Arn. Arb. et Hb. Schneider). Judging by the fruiting material only, I believe this species is best placed in sect. DENTICULATAE Schn. near S. denticulata And., but it can be distin- guished at once from this species by its much larger hives: The yellowish nervation is very conspicuous on both surfaces of the leaves. I am not able to determine the real relationship of the new species, not having seen any male WS \ Salix (probabiliter sect. PHyLiciFoL1AE Dum.) squarrosa, n. sp. Gee E, .1-5)—Frutex erectus, squarrosus, breviter ramosus, ad 4 m. altus; ramuli hormotini non visi, annotini nigro- -sesnagasren, glabri vel cai sie ad gemmas parce pipsseh, peranne foliiferae itis chioagne acutae, subadpressae, cire. I cm. longae, flavo-brunneae, glabrae. Folia nondum evoluta vel minima, vix ad 1 cm. longa et 3 mm. lata, superne glabra, subtus _ dense longe sericea sed ut videtur cito glabrescentia, integerrima, - nervis lateralibus vix visibilibus, matura ignota. Amenta prae- om sessilia, patentia, ovato-elliptica, vel breviter cylindrica, -1.5-2.8 cm. longa, circ. 1 cm. crassa, dense albo-sericea, tantum feminea visa ; bracteae ovatae, subacutae, ovaria florum superantes sed vix apicem styli attingentes, nigro-fuscae, utrinque longe ser- -jceae; ovaria ovata, dense breviter sericea, breviter pedicellata, ete glandulam aequante vel sublongiore; styli fere glabri, — -distincti, elongati, dimidio ovarii aequilongi, stigmatibus oblongis apice haud vel paullo emarginatis stylo brevioribus coronati; — - landula una, ventralis, Pag ae ees apes. truncata. oe ie vix satis maturi pedicello sti c ee 1917] SCHNEIDER—NEW CHINESE PLANTS 143 This is the first willow from central China, I have seen, which apparently represents a species of sect. PHYLICIFOLIAE Dum. It is a much branched tall shrub with short spreading branchlets. The short, silky female aments are perfectly sessile. Without having seen mature leaves and male flowers, however, it is impossible to be sure of the real relationship of the species. \\55 Salix (sect. Drptopicryar Schn.) Faxoniana, n. sp. (fig. H, I~5).—Frutex parvus, ramis prostratis radicantibus, ramulis ascendentibus, o.2-0.3 m. altus; ramuli tantum novelli initio sericei, annotini glabri, flavo-brunnei, biennes vetustioresque obscure brunnescentes, deinde nigrescentes; gemmae elliptico- oblongae, subacutae, circ. 5 mm. longae, glabrae. Folia obovato- elliptica, elliptica vel elliptico-oblonga (vel minima ovato-elliptica), apice rotundata, obtusa vel breviter subacuta, basi late cuneata vel rotundata, 1.5:1 cm. ad 3.5:2-2.3 cm. vel angustiora ad 3:1.5 cm. magna, superne intense viridia, subnitidula, glabra, tantum in costa subimpressa vel plana versus basim pilis sparsis praedita, subtus valde discoloria, cinerascentia vel albescentia, pruinosa, in costa nervisque lateralibus prominulis utrinsecus 6-10 angulo 7o-80° a costa divergentibus pilis sericeis sparsis instructa vel glabra (juvenilia probabiliter dense sericea), reticulo nervillorum satis distincto, margine satis indistincte et distanter glanduloso- crenato-denticulata; petioli satis longi, superne in sulco lato plus minusve puberuli, 8-13 mm. longi. Amenta tantum fructifera — visa, ramulos ad 3 cm. longos normaliter foliatos terminantia, cylindrica, densiflora, ad 5 cm. longa et circ. 1 cm. crassa, axi laxe villosula; bracteae florum inter fructus remanentium oblongae, fuscae, obtusiusculae, dimidio ovarii aequantes, versus basim parce villosulae, apicem versus glabrae, plus minusve ciliatae; ovaria elongata, conica, basi in pedicellum brevissimum quam glandula -duplo: breviorem attenuata, oabek vel basi sparse villosula; styli sicnett ee aa 144 BOTANICAL GAZETTE [auGuST Schneider (no. 2319; typusin Herb. Arb. Arn. et Hb. Schneider; frutex 0. 2-0.3 m. altus); in declivibus rupestribus montium inter flum. Yang-tze et oppidum Chung-tien, alt. circ. 3400 m., mense Augusto 1914, C. Schneider (no. 2375; forma nullo modo ab no. 2319 diversa). At first sight this species very closely resembles S. oreinoma Schn. from the high mountains of western Szechuan, but S. Faxoniana differs from it and from the other Asiatic species of sect. DrpLopictyAr Schn. in its glabrous ovaries, the fruits being sometimes hairy only at the very base. The leaves are similar to those of S. oreinoma, but the catkins of this species speente only about 2 cm. in length (without the -sasaieds ,an and the bract zg , broader, and truncate at the apex. i pliment to Mr c E, Faxon, the assistant director 2 the Arnold Arboretum. SALIX BRACHISTA Schneider in Sargent, Pl. Wils. 3:145. 1916.— I described only a male specimen, and I add the following descrip- tion of the female pent: dct: pygmaeus, trunco subterraneo, bentik 1s; ramuli prostrati, initio olivacei vel Parveackntes, dein flavo-brunnei vel flavo-rubri, tantum novelli _ parce pilosuli, cito glabrescentes. Folia parva vel perparva, crasse _papyracea, elliptica vel ovato-elliptica, utrinque acuta vel pleraque apice acutiuscula et basi subrotundata, minimis exceptis 6:2 mm. _ ad 12:6 mm. vel maxima ad 17:9 mm. magna, superne satis viridia, costa incisa, nervis lateralibus planis vel vix levissime prominulis, glabra, subtus pallidiora, non eaeecortie, costa nervisque aoe lateralibus utrinque 5~7 angulo circ. 50-70" a costa divergentibus — -distincte prominulis, an initio pilosa?, adulta glabra, margine : Me subintegerrima vel plus minusve distanter minute ee oo petioli oe superne sulcati, 2-4 vel foliorum 8mm longi, ger mas plus minusve duplo superantes. Amenta trate - pauca tantum v termi- — zaflora; f fructus maturi, obovato-oblongi apice attenuati, : 1917] SCHNEIDER—NEW CHINESE PLANTS 145 3500 m., mense Augusto 1914, C. Schneider (no. 3454; ramuli fructiferi in Herb. Schneider). . It is with some hesitation that I refer this female willow to S. brachista Schn., which is known only from male specimens collected by E. H. Witson in western Szechuan. In most of my specimens there are no flowers or fruits, the apex of the | hlets being infected probably by an insect and transformed into hairy galls. The leaves agree well with those of typical S. brachista in the nervation and color. Together with no. 3454, I collected another female willow (no. 2318), the leaves of which are even a little smaller, of a somewhat firmer texture, with veins slightly impressed above and scarcely visible on the rather bluish grey under surface. I am not sure whether or not this form belongs to the Hima- layan S. Lindleyana Wall. or represents a form of S. Souliei Seemen. It is not quite identical with those female plants from Tachien-lu which I described in Pl. Wils. 3:62 as S. Souliei. I think it best, therefore, to give the following description of no. 2318 from the snow mountains near Lichiang-fu: Frutex pygmaeus facie S. Lindleyanae Wall. vel S. serpyllifoliae Scop. ramis solo vel rupestribus adpressis, ramulis brevibus junior- ibus olivaceis glabris (an novellis pilosiusculis?). Folia perparva, crassiuscula, elliptica vel ovato-elliptica, utrinque obtusa vel subacuta, rarius basi subr. minimis exceptis 5-7 mm. longa, — 2-3 mm. lata, superne satis laete viridia, glabra vel in costa incisa sparse pilosa, nervis lateralibus plus minusve distincte incisis, ebeed satis discoloria, glaucescentia (etiam novella ?), costa, prominula, nervis lateralibus t utrinsecus 2-4 angulo 40-45" & Costa divergentibus vix vel haud \ visibilibus, margin vel a sa ti ; petioli distincti, 2-4mm. longi, superne interdum ae gemmas duplo superantes. 2 Amenta ramulos perbreves liter foliatos t antia, fructi- tera. Seteagierity circ. ‘Sf attenuata, | ed ls sea redicellata, | 146 BOTANICAL GAZETTE [AUGUST ‘L°* Salix (? sect. SrEBOLDIANAE Seem.) dibapha, n. sp. (fig. I, 1-6).—Frutex erectus, ad 4 m. altus, ramuli hornotini laxe vel densius villosuli (novelli satis dense flavescenti-tomentelli), anno- tini satis glabrescentes, atro-fusci, vetustiores glabri; gemmae foli- iferae ut videtur flavo-purpureae, subglabrae. Folia papyracea, elliptica vel elliptico-oblonga, apice acuta vel longiora sensim brevi- ter acuminata, basi cuneata, superne vivide laete viridia, tantum valde juvenilia plus minusve flavescenti-sericeo-tomentella, costa prominula nervisque partim exceptis cito glabra, subtus valde discoloria, glauca, pruinosa, initio ut supra sericeo-tomentella, sed citissime glabrescentia, tantum in costa elevata parce sericea, nervis lateralibus utrinsecus 10-20 angulo 80-go0° a costa diver- gentibus prominulis, reticulo nervillorum foliorum immaturorum valde tenui vel vix visibili adultorum probabiliter magis conspicuo, margine integerrima, minimis exceptis inferiora elliptica 4-6 cm. longa et 1. 4-2 cm. lata, superiora oblongiora ad 8:2.4 cm. magna; petioli 4-7 mm. longi, undique sericeo-villosuli; stipulae minimae, semicordato-lanceolatae, villosulae, margine glanduliferae, vix ad 3 mm. longae. Amenta tantum fructifera visa, praecocia, elongato- cylindracea, pedunculo ad 1 cm. longo foliola pauca parva ad 1-5 cm. longa ab normalibus vix diversa gerente Sayeed ad 8 cm. longa _ et o.9 cm. crassa, axi villosa; flores i tes 2-3.5 mm. longi; ovaria ovata, sessilia, dense piliacaia: styli breves sed _ distincti, {-} ovarii aequantes, apice breviter bifidi, stigmatibus brevibus subbifidis oblongis; glandula 1, ventralis, oblonga, satis _ brevis, bracteis florum adultiorum subduplo brevior; bracteae ovariis juvenilioribus | aequilongae, elliptico-oblongae, obtusae, _ brunnescentes, intus glabrae, extus infra medium villosulae et _ciliatae, apice glabrae, ovariis adultioribus fere 3-plo breviores. : oo Fructus ao ovato-oblongi, apice paullo attenuati, basi in | 22 sage glandula breviorem contracti, satis dense albido- = : st} lis siccis eivasee circ. 3- s4 mm. ae set valvis 1917] SCHNEIDER—NEW CHINESE PLANTS , 147 distinguished by its more acuminate leaves with a longer silky pubescence on the under surface, by its somewhat thinner fruiting catkins, its longer gland, and by its longer more ees. cleft styles. The specific name is derived from déBados, ‘double colored.” In Pl. Wils. 3:122 I described a S. isochroma, referring it to sect. HETERO- CHROMAE Schn., but according to further observations I believe that this species represents only a variety of S. hylonoma; therefore, I suggest the following combination: S. HYLONOMA var. isochroma Schn., n. var. Alnus (subgenus CrEMASTOGYNE [Winkl.] Schn.) Ferdinandi- Coburgii, n. sp—Arbor; ramuli novelli ut videtur dense fulvo- villosulo-tomentelli, annotini plus minusve glabrescentes, atrofusci, lenticellis sparsis flavo-brunnescentibus obtecti, vetustiores nigres- centes; gemmae stipitatae, subglobosae, subglabrae, resinosae. Folia matura chartacea, late elliptica vel subobovato-elliptica, apice satis subito in acuminem brevem producta, basi rotundata vel fere semper cordata, minora 5—7.5 cm. longa, 2.5—4 cm. lata, a ad 14:8 cm. mint, oe pracsertim ad apicem satis liter breviter gland serrata, superne satis obscure viridia, costa incisa breviter glanduloso-pilosa excepta glabra, nervibus planis, subtus discoloria, glaucescentia, pruinosa et sub microscopio subpapillosa, glandulifera, ad costam nervosque laterales valde prominentes flavobrunneos utrinsecus 12-17 plus minusve fulvo- (et Bianduloso-) villosula {novella probabiliter | satis dense t ; petioli crassi, superne sulcati, glanduloso-villosuli, ‘61 mm. Tongi. Amenta tantum feminea fructifera visa, pro subgenere Cremastogyne nor- malia, ovato-elliptica vel ovato-subglobosa, ad 2 cm. longa et 1.5 cm. 2 Crane, plus minusve resinosa; pedunculi 10-15 mm. longi, laxe i; > bracteae ut in tabula fig. bs a4 dehurstae, apice eee ae ee Sods : , circ. 12mm. _ Tongae et (apice) subaequi latae; semina obovato-rectangularia, — - circ. 4 man, longa, als anes Cte. ee ae tL 148 BOTANICAL GAZETTE [AUGUST the broadly winged seeds of the two other known species of this group. The female flowers of the new species are yet unknown. As I pointed out (I. c.), the subgenus Cremastogyne is a very distinct one, and differs widely from subg. A/nus Endl. and Almaster Endl. in its single male and female aments, which appear in the spring on this year’s branchlets in the axils of normal leaves. The male flowers are entirely apetalous (fig. K, 6-9), and the female flowers, so far as I can see, agree well with those of the other subgenera; they are shown in fig. K, 10-12. In fig. K, 12, the small “‘prophylla” of the female flowers can be seen, which are hairy at the apex. In A. cremastogyne the female flowers I have seen had always 3 stigmas. The fruiting bracts and the seeds of A. Janata are represented in fig. K, 14-16; those of A. cremastogyne are very similar. I take the liberty of dedicating this excellent species to His Majesty King oe I of the Bulgarians, an eminent botanist and patron of natural ‘Anxoxp Ansonertit EXPLANATION OF PLATE XV Fic. A—Saliz tenella: 1, young female flower with bract; 2, 3, stigmas; 4 Venee eee 5, dorsal gland; 6, bract with dorsal a cha? B.—Salix Balfouriana: z, old female flower with bract; a ventral - gland; 3, bract; 4, mature fruit. : Lo ot -C.—Salix Guebriantiana: male flower; 2, anthers; 3, ~ ventral gland; 4, both glands with the base ofthe laments De bette thea : dorsal g Fig. D.—Saliz cites 1, old female flower with bract; 2, — ‘Fie. E.—Salix squares 1 female ower with Dract; 2 ’, stigmas; ah ¥ oda PLATE XV BOTANICAL GAZETTE, LXIV SCHNEIDER on CHINESE PLANTS REPRODUCTION IN THE CONIFEROUS FORESTS OF NORTHERN NEW ENGLAND" Ba MoOoRE This ‘investigation was undertaken to determine the factors governing the reproduction of the more important coniferous trees in the forests of northern New England. A detailed study of a single area was considered more effective than general observations over a wide area, but the — is not by any means exhaustive for the single area. The work was done on Mount Desert Island, situated toward the eastern end of the coast of Maine, in about the same latitude as the northern part of the Adirondacks and northern New Hamp- shire. The island is included in the spruce region according to Hawtey and Hawes (3). This is strictly correct; nevertheless, parts of the island show unmistakable ; signs of the more southerly white pine region. The location of the island is” therefore. of unusual interest. Being at the edge of the tension zone between I50 BOTANICAL GAZETTE [AUGUST are precipitous, due probably to water action during the post- glacial submergence (5). The northern half of the island is com- paratively level. The topography therefore offers a diversity of habitats. The climate of the island is a curious mixture of the marine and the inland, the former, of course, predominating, but the latter being found in places shut off from the ocean winds. On the north- east side of the island the average annual precipitation is 48.3 inches, of which 16.1 inches or one-third comes in the growing season (May-—September inclusive). This should be abundant, but there are periods during the summer in which lack of moisture is an important factor. The mean annual temperature is 44° F., running from 21° in January to 65.5° in July. The sea tends to keep the temperature uniform, but it is uniformly cold, for it is beyond the Gulf Stream. _ There are surprising fluctuations in temperature, however. The large areas of exposed granite rock take up and radiate great quantities of heat, so that the fluctuations, particularly in places cut off from the ocean winds, must have a distinct bearing on the ~ vegetation. : The vegetation, although predominantly northern, contains a _ strong mixture of middle Atlantic elements. It contains not only plants but forest associations belonging to both the boreal and the _ transition zones (4). Furthermore, this island and Schoodic Point, a small peninsula about ro miles to the eastward, are isolated - stations for Pinus divaricata. _ The forest associations of the island are 5 in number: (1) _ spruce, (2) white pine, (3) cedar, (4) pitch pine, (5) grey birch- — aspen. Over most of the island, except the parts recently burned, ae the first 3a associations mingle in a rather confusing manner to form a : : oe eae iotest containing eee di Proportions of red spruce, balsam fir, ne, and white cedar, with an admixture of red maple, grey 2 1917] MOORE—CONIFEROUS FORESTS I5r (Pinus Strobus). It occurs on almost any site, even bare rock, provided there is moisture. 2. The white pine association, composed of nearly pure white pine, isnot abundant. The association on Mount Desert, although | predominantly white pine, contains a strong admixture of red spruce and cedar, and sometimes of red pine (Pinus resinosa). It occurs on somewhat drier sites than the spruce association. 3. The cedar association does not form as pure stands as the two preceding ones. Although cedar predominates pa NeIE there are generally considerable proportions of fir, spruce, an white pine, with red maple (Acer rubrum) and paper birch te papyrifera). It occupies the moist flats. 4. The pitch pine (Pinus rigida) association, generally sharply separated from all others, is composed of pure pitch pine, or some- times pitch pine and a little red pine. It occupies mostly the dry rocky southern exposures. On rocky flats not exposed to full _ isolation, white pine, fir, and spruce are creeping in under the pitch pine; on these flats, if not elsewhere, the pitch pine appears to be a pioneer association. 5. The grey birch-aspen (Betula populifolia Populus tremuloid and y, following fires, andi is ae sooner or later by the original coniferous forest. : A striking feature of these forests, a ninsaaos common to many spruce forests in the west as well as in th e of fir reproduction under the spruce, even when the parent stand is nearly pure spruce. It is unnecessary to go into the many hypotheses advanced to explain this. Perhaps the most wide- spread theory, and the one tried out in this investigation, is that _ the accumulation of acid in the soil under the spruce is detrimental . : : _ to spruce and favorable ne fir. . _@) shows that certain p or a racy th soi. ‘Could 2 s 152 BOTANICAL GAZETTE [AUGUST same size and age, and were taken from the same place, so that variations due to size and vigor are eliminated. Each soil was placed in a flat approximately 8 cm. in depth, over which was placed a lath screen made so as to give half shade. All flats were in the open, were given no artificial watering after the first 2 days, and consequently were all under the same conditions except for the soil. These conditions were, furthermore, as close to natural forest conditions as possible. The 3 soils were (1) A thoroughly decomposed ‘forest humus which had been taken from the forest and rotted in a field for 2 years. This has a moisture-holding capacity, when saturated, of 138. 5 per cent of its air-dry weight, or 82.6 per cent of its volume. (2) Undecomposed raw humus, taken directly from the spruce association, consisting of needles, cone scales, and other forest litter. This is Cov1tLe’s “upland peat,” the forest “duff”? which accumulates in northern regions because decomposition is retarded by lack of sufficient warmth. Its moisture-holding capacity, saturated, is 504.6 per cent of its air-dry weight, but only 65.1 per cent of its'volume. The high percentage of water on the basis of air-dry weight gives an idea of the extreme lightness of this raw humus. (3) Mineral soil from beneath the raw humus. This is a ___ bouldery glacial till, a reddish brown sandy loam with but little i properties faa The reason is that it was _ impossible to make wheat or corn produce sufficient root systems ce oS in either the raw humus or the mineral soil. On the decomposed - nus (soil [2] above) a single direct det wilting : effi aha of 13 per cent. Calculations from the moisture-holding & < ci ty at B eeteree,. which : are probably unreliable for these” iIting nts of 21 sae 1917] MOORE—CONIFEROUS FORESTS 153 The decomposed humus was found to be neutral; the raw humus showed an acidity of o.002 normal, and the mineral soil an acidity of 0.00017 normal by CovILLE’s method. Yet by the TRuoG method the raw humus was strongly acid, and the mineral soil of medium acidity. Tests at the end of the growing season showed only a small diminution in acidity. The measurements showed that the growth of both fir and spruce was most rapid on the mild humus, effectually disposing of | the theory that acidity is required by fir, or favors the fir against f the spruce. In fact, the difference in rate between the neutral and acid cultures was greater in fir than in spruce, indicating that spruce withstands acidity better than fir. Growth of both fir and spruce on the mineral soil was slightly more rapid than on the raw humus, except that toward the end of the season some of the spruces on the raw humus began a second growth period which enabled them to pass those on the mineral soil. White pine also did better on the mild humus than on the mineral soil; on the raw humus there were not enough trees of this species for erie conclusions. | The duration of the period of growth in length for the different : species is interesting. Fir began elongating on June 1, and stopped ct on July ro, 40 days later; spruce and pine began on June 5, and did not stop until August Bese 10 aae eee ee _ long as that of fir. Some of the spruce on the raw owed a second growth period lasting until August 303 disk get its shorter growing period, is a faster growing tree than spruce. : a An examination of the root systems of the different species on — the different soils, made at the end of October, revealed a oe 154 BOTANICAL GAZETTE [AUGUST The roots of all species were thicker and thriftier looking on the raw humus than on the mild humus, although fir and white pine were a little more branched on the mild humus. Most striking of all, the roots of all 3 species on the raw humus were still capable of absorption, even at the end of October. This was shown by the presence of a considerable number of the little translucent growing tips which are found during the height of the growing season. On the mild humus growing tips capable of absorption were almost lacking except where the root came in contact with the wood of the flat. In the raw humus the root tips which had ceased to function became brown, while many of those on the mild humus became covered with a white fungus. A black fungus, common in the raw humus of the forest, was found attacking the roots on the mineral soil more than those on the raw humus, indicating that its presence may be due to low vigor on the part of the roots rather than to abundance of spores. The rootlets in the raw humus exhibited a propensity for searching out twigs and cones and growing through them. - - Raw humus appears to have an effect on damping off fungus, _ quite the reverse of what might be expected. In an experiment to determine the effect of drying out, such as the raw humus is sub- | jected to under natural conditions in the open, upon the germina- tion and establishment of Pinus resinosa, it was found that on raw a humus kept artificially moist there was no damping off, while on the raw humus which received no water except from rain the loss _ a from damping off was 44. ‘ ner cent of the seedlings germinating. yrse on a dry than on a moist : cn soil i is contrary to all previous gene The explanation is _ probably y to hag found it in the great abundance of fungus spores in y nursery soils, and in the LS 1917] MOORE—CONIFEROUS FORESTS 155 Experiments were also tried on the effect of these 3 soils on the growth of clover, wheat, and corn. Clover, as might be expected from its sensitiveness to acid, grew very poorly on the raw humus and mineral soil, but throve on the mild humus. In fact, it eventually died back and disappeared on the two former, lasting longer on the mineral soil than on the raw humus. Kubanka wheat did well on the mild humus, except for the shading, while on the raw humus and mineral soil it grew poorly. The dry weights per plant for Kubanka wheat sown June 24 and cropped Septem- ber 15 were 0.53 gm. for the mild humus as against 0.08 gm. on the raw humus, and only 0.03 gm. on the mineral soil. Corn (Golden Bantam) did so well on the mild humus that it had to be removed to prevent interference with the other experiments, while on the raw humus it produced only 0.09 gm. dry weight per plant, and on the mineral soil 0.13 gm. after growing for more than 3 months. The corn, it will be noticed, did better on the mineral soil than on the raw humus, indicating that this plant is affected more by acidity than by’ poor aeration. On the other hand, wheat grew better on the raw humus than on the mineral soil; on the former it frequently died down but came up again, while on the latter it showed less power of recovery. This would indicate that wheat is less sensitive to acid than to poor aeration. = Field observations on the root systems of spruce, fir,and white _ pine showed that detailed studies of roots would probably yield interesting results. Spruce roots form a dense mat in the raw humus or “duff,” a mat so dense that hardly a square ce timete under a spruce stand escapes. These rootlets keep i ee ene pleas as athe humus Sonn those i in the | a | — cory ke ‘enormous, cade cannot t fail to be : an . _Teproduction. “Fir roots a are | Cc all 156 BOTANICAL GAZETTE [AUGUST affected by a fungus which produces black threads of mycelium on the root tips. These threads prevent absorption and kill the por- tion of the root attacked. Yet seedlings appear thrifty even when a large proportion of their roots are affected in this way. Perhaps, since the fungus attacks only the smaller rootlets, the plant is able to develop new rootlets about as fast as the affected ones die off. A factor of more importance than hitherto recognized is dryness due to the interception of precipitation by the crowns of spruce. The lack of vegetation under a forest of spruce has generally been attributed to lack of light. While light plays an important part, there are probably many cases where lack of moisture rather than lack of light is the determining factor. A rather striking illustra- tion may be cited. Under the crown of a spruce growing in the open was found a patch of forest floor similar in every respect to the forest floor found under dense stands of spruce. Herbaceous vegetation and tree reproduction stopped abruptly at the edge of this spot, yet the crown of this tree was high enough to allow the ground under it to receive ample light. The only végetation under _ the crown was a few grasses and asters, light demanding but com- _ paratively drought resistant plants. The bareness of this piece of _ forest floor was due to lack of moisture, not to lack of light. This was confirmed by moisture tests, which showed that the soil : _ beyond thé crown, soil which had been giving up moisture to a _ thick herbaceous cover all summer and should consequently be | rer than a spt which had given up nothing to vegetation and oe 1917] MOORE—CONIFEROUS FORESTS 157 often so dry that neither reproduction nor herbaceous vege- tation can become established, no matter how much light it receives. Counts of the reproduction of spruce, fir, white pine, and cedar, correlated with age, showed that spruce, fir, and white pine become established only at intervals of several years, while cedar comes in every year. The cause of the failure of spruce and fir to become established every year is apparently not related directly to climatic factors, because the season of 1916 was unusually moist and favor- able, yet practically no seedlings of these 2 species could be found. Probably the reason for this periodicity in spruce and fir reproduc- tion is to be sought largely in the seed supply. White pine repro- duced abundantly in 1916, so that climate can be eliminated as a_ factor; but since it is equally impossible to eliminate the matter of seed production, the periodicity of white pine reproduction may be due to both the season and the seed supply. In fir there are indications of a periodicity of reproduction which is of Poneuieranty more suse ehoorenio | en that due » the seed supply. 1 about middle age, the fir reereduction is ‘nearly all composed. of large : a seedlings approximately 1-3 ft. in height; young seedlings are Scarce. In these cases it appears that the fir came in profusely a : : — a set of savisenies conditions different from the present oe Just what these conditions were it is impos: : out ie fester shy One of them may have been stronger light than at present. Indications of this were found in. the fact that some _ _ Of these cases of fir reproduction occur in stands which were for- _merly more open than they now are; also, small fir repr duction is abundant in young stands with a full but not very heavy canopy. = sion @. _ Another factor may b be d 2s lecré ible to pos tea - = 153 BOTANICAL GAZETTE [aucust Each species reproduces only within a certain range of factors. This range is probably a specific characteristic of each tree, possibly of each plant, and appears to be different even for trees growing together in the same association.?, Determination of this range for even a few of our more important trees would be a valuable contribution. New Yorx« Criry LITERATURE CITED 1. BoerKER, R. H., Ecological investigations upon germination and early growth of forest trees. Univ. Neb. Studies 16:1-89. 1916. 2. CovIL_e, F. V., Experiments in blueberry culture. U.S. Dept. Agric., Bur. Plant Ind. Bull. 193. 1910. 3. Haw ey, R. C., and Hawes, A. F., Forestry i in | New England. New York: ened — Pt C. Hart, Laws of temperature control of the geographical dis- - tribution of tweed animals and plants. - Geog. Mag. 6:229-238. 1894. 5. SHALER, N. S., The geology of the island of Mount Desert, Maine. Report ee Secretary Interior 37987-1063. 1889. « Sureve, F., The vegetation of a desert mountain range as conditioned by climatic factors. Car. Inst. Wash. Publ. 217. rors. 7 Truos, E., EOeN eh te all sent i maios Sta:; Saiu: Wis. Bull. 249. 1975 : oem, R,, Balsam fir. US. Dept. Agric. Bull. 55+ 1914. _Stti (fond hat in pen eget in Ain he eis vg POLLEN TUBE AND SPERMATOGENESIS IN IRIS CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 235 M. Louise SAWYER (WITH EIGHTEEN FIGURES) This study of spermatogenesis had its origin in an attempt to find a satisfactory method of securing prepared as well as living material for demonstrating pollen tubes to a class in embryology. The fact that it was found possible to dissect out the pollen tubes of Iris versicolor, so that tubes of various lengths, developed on the stigma and style, became available for study, made it seem advis- able to undertake an sph itiat of the pollen tube of this species. Tubes were also secured in longitudinal sections of style and stigma, and by sowing pollen grains on n culture media. ‘Tubes were grown in sugar solutions, the 15-30 per cent proving more satisfactory than weaker solutions. A culture medium was made by adding 30 per cent sugar solution to the sap which oozes from freshly cut stalks, and abundantly from the clasping bases of the leaves. The superiority of the latter over the pure sugar solution lies i in the fact _ that as the tubes grow longer they are less likely, in the cell = oe ‘sugar solution, to become distorted. Its disadvantage consists in the difficulty of freeing the tubes from the gelatinous medium. — : Flemming’s stronger solution proved the most satisfactory kill- : ing fluid, and iron-hematoxylin has been the favorite stain. successful dissection of the tubes is related to the structure of ‘the e : Style. That organ arises from the ovary as a single structure, and Lae oe at the height of about 1 cm. divides into 3 bra nches. ! _ Of a stylar branch (fig. 1) reveal the fact that cach branch is eee an, __ ersed by a longitudinal groove. When the flower is re, the _— Stylar- rove is vee ee wo | BOTANICAL GAZETTE [aucusT IQO0 a ee and ” . » X124; | oe Os © ee grow, ‘om section of anther, | view of tube nucleus and | a 1-10.—Abbreviati iation: s are as foll ws: fig. 1, transvers ae pollen tubes ie fron i) Se, bg e: : Bex a CAS 2 s Wegurse Sass oer, , preeaaite 1917] SAWYER—IRIS 161 is continued beyond the stigma. By removing the covers of the groove the canal containing the tubes lies exposed, and they can be removed with needles. Tubes grown in hanging drops of culture media show a rather striking tendency to grow from the margins of the drop in groups, the tubes being in close contact with each other. This fact is sug- gestive when associated with the fact that from the stigma the pollen tubes converge in two lines and traverse the stylar branch at the margins of the groove, where the space is most restricted (fig. 2). It has usually been assumed that the pollen tube is guided in its direction of growth by chemotaxis. These observations suggest that in Jris contact stimulus may be an effective guide. Further investigation of this point is purposed. _ The structure of the newly formed pollen grain (fig. 3) was studied in sections of the anther. The division of the microspore nucleus was not observed, but it occurs in the anther, as would be expected, and the generative cell is organized before dehiscence _ (fig. 4). The generative cell is slender, elongated, and somewhat 2 pointed when seen from the side (figs. 6, 13), and is fi over- laid by the tube nucleus (figs. a: 5). In this condition the pollen — is tin _ Hand pollination was successfully performed. ‘Usually d, bu speed fies oad a ees the si t it was demonstrated ne eee ae under which i it was located. “Observation on the rate of growth - SS ny Be oes e, and thei sa ieths se measured with an ocular micrometer. T 2 ndicates BOTANICAL GAZETTE [AUGUST 102 t, ws: pg, pollen grain; Abbreviations are as follows: p¢ 0 Pe ns . - 1917] SAWYER—IRIS 163 within the ovary. The pollen tubes occasionally branch. This / was observed both in tubes grown on the stigmas and in those grown on nutrient solutions (fig. 8). In the cell sap sugar solution some grains produced 2 tubes (fig. 9), indicating 2 germination spots. Longitudinal sections of hand pollinated stigmas (fig. 11) show pollen grains (fig. 5) which have essentially the characteristics of the grains in the dehiscing anthers, and among them grains which are producing pollen tubes. A tube (fig. 10) caught just as the tube nucleus and the generative cell were passing the tube dis- tinctly shows the latter preceding, contrary to the order that is usually reported. In other cases, the tube nucleus led the way from the grain into the pollen tube (fig. 7). The number of cases thus far observed at just this stage is not sufficiently large to war- rant a statement as to which of these conditions is prevalent in Tris versicolor. Apparently it is usual for the tube nucleus to soon gain the leading position. One instance (fig. 14) of the tube nucleus in the act of passing the generative cell was observed. The peculiar elongated and pointed anterior end of the tube nucleus is very interesting and suggests a self-motile body. The generative cell certainly usually passes into the tube before its nucleus divides to form the male nuclei, but occasional grains suggest the possibility that it sometimes divides in the grain. The division of the generative cell has not been observed, but in tubes _ dissected from the stigma, and in those grown in the culture media, ce the generative cell has frequently been seen apparently containing — 2 nuclei (fig. 15m). The contents, which microchemical tests show _ contain much starch, stain so heavily that it is difficult to differ- ee : entiate the nuclei satisfactorily. The material seems to indicate a : : eS _ Somewhat wide 1 a in | the position of the generative oe in i oS 164 BOTANICAL GAZETTE [AUGUST in all of these cases no cytoplasm could be detected in association with the male nuclei, and also that in all views of these male nuclei one of them appears larger than the other, the larger one slightly vermiform. It remains to determine whether this apparent dif- ference is real or whether in each case one of the nuclei is seen from the end. In the embryo sac section it seems probable that the smaller appearing one is the one likely to fertilize the egg. Summary . The style of Iris versicolor is traversed by a longitudinal groove through which the pollen tube grows. 2. It is possible to remove pollen tubes from style and stigma and to grow pollen tubes in nutrient solutions. _ 3. Measurements indicate that there i is an accelerated rate of growth of pollen tubes. 4. Pollen tubes may branch or a grain may produce two tubes. _ §. The generative cell is an elongated, somewhat pointed cell, — tured precede the tube nucleus from the tube. usuall y Occurs: aiter the penera- 2 ed tv cl has entered the tube. 4. The male nuclei may leave the ecmative cytoplasm, and a been eee a a ae The male nuclei were serve ‘ ed in the embryo sac 79 hours : 2 after pollination. oes oy writer is in debted to 5 Proke fessor oH. D. Dexswone of Beloit oe | College for suggestion which led to aking of this inves- _ tigation. “Acknowledgments | are = ~ Professor ae M. 2 Courter and Dr. CHARLES Tt. ‘the p tl ae Seal BRIEFER ARTICLES ELLSWORTH JEROME HILL (WITH PORTRAIT) E. J. HILt was a well known figure to the Chicago group of botanists. For over 40 years he studied the plants of the Chicago region. No one was more familiar with them, or had brought so many of them to general notice. He was much more than a collector and taxonomist; in addi- tion, he was an ecologist before ecology was recognized as a subject. He was born at LeRoy, New York, December 1, 1833, and died in Chicago, January 22,1917. His early life was spent on a farm, in which environment he began to develop his love of natural history. At the age of 19 he was taken suddenly lame by an affection of the knee, and during the rest of his long life, with intervals of relief, this troubleaccompanied hi After his first trouble, to eet away from the northern winter, he went to Mississippi and taught for three years in a woman’s college at Grenada, afterward returning to New York. In 1860 he began a theological course in Union Theological Seminary, graduated in + 10h, and engaged in pastoral work until 1869, when another attack of lameness incapacitated him for two years. He then became a teacher again, first in the high school of Kankakee, Illinois, for four years, and then for fourteen years in the high school of Englewood, now a part of a Chicago. In gee he gave up teaching and seiotens et eae oo : entirely to botany. 166 BOTANICAL GAZETTE [AUGUST Hill’s experience as a persistent field student is a lesson in patience and courage. His numerous field trips on crutches and afterward with canes; his devices to overcome the handicap of lameness while collecting; his persistence in making these trips even when he paid a severe penalty for exposure or over-exertion—all testify to the spirit of the man. Dur- ing his later years he was a constant and welcome visitor at the weekly. meetings of the Botanical Club of the University of Chicago, and was always intensely interested in the various phases of modern botany. His mind was open and progressive, turned toward the future of his sub- ject rather one toward the past. His | lished includes 162 titles, ranging in time from 1870 to 1916, and covering all the phases of botany that would attract the attention of an active field man with broad interests. This journal published 34 of his titles, the majority of them during the decade 1880- 1890, and the last one in toro. Certain genera received his critical attention, among them being Potamogeton, Carex, Quercus, Prunus, Salix, and Crataegus. Taxonomists will recognize the fact that these are difficult genera, but it was their difficulty that attracted. _ The Hill Herbarium, which is said to include 16,000 sheets, the accu- mulation of years of critical work, has been secured by the University of ‘Illinois. It represents probably the most valuable single collection of Illinois plants, especially of the Chicago region, and it is fortunate that | ae as te es ee M. C. — RESISTANCE OF SEED COATS OF ABUTILON THEOPHRASTI TO INTAKE OF WATER oe In the fall of 1910 I gathered seeds of Abutilon Theophrasti (velvet _ leaf) near Manhattan, Kansas, placed them in vials of roo seeds each, — covered them with water, and stoppered the vials. ‘The results in the e present time have been very similar. a shad swollen within the ist 5 weeks and were -xamine In December 1916 a “desk i in which o 1 and | x on erates the past 6 years 22 of the remaining — 1917] BRIEFER ARTICLES 167 and germinated as quickly and apparently with as much energy as fresh seeds. Of the original 100 seeds 24 still remain intact. In order to ascertain the resisting power of the seed coats of velvet leaf to water at various temperatures, in December 1916 I collected seeds from plants still standing in the field. | Most of the seeds at that time had dropped from the pods, and those I found were mostly hard- coated. In one case only 3 seeds in 100 had swollen after soaking 48 hours at room temperature. Two lots of seeds of 100 each were selected and each lot was placed in a small vial. The vials were then filled with water at a given temperature and suspended in Dewar flasks filled with water at the same temperature. At the end of 6 hours the vials were removed, the seeds that had swollen were counted, removed, and the naire seeds were returned for a similar period at a tem- perature 5° higher, and so on until all the seeds had swollen. The tem- perature of the flask for each period was kept practically constant. The seeds in flask no. 1 were started at 30°C., and in no. 2 at 35°C. The results are indicated in table I. TABLE I FLASK NO. I Fiasx No. 2* Tempera- | Ti Number ~| Ti Number Re er |) ee Pe eee ee ac. 6 8 35 C... 6 e S 5 eee 6 9 Se 6 oo ae 4° Ce 6 Ig Ce * 6 12 : 6525-5 6 se es ee 6 as oe oo 6 8 (Cage 6 13 See.0 lS, 6 cs eae 6 9 60... 6 12 G6. ..2 6 to 6§... 6 7 eee 6 oS 2 6 iS § ys. 6 4 75: tye es 6 5. oe = _Tesistant may lie i in the soil many years 1s befo —Wier E. D, Kan CURRENT LITERATURE BOOK REVIEWS Contributions to plant physiology In a little booklet’ of 95 _ is given the work of the department of plant physiology at Johns Hopkins University. Livincston gives a description of the department, discussing the aims kaa the work in progress or so far accom- plished, to which is appended a list of the publications from the laboratory arranged by years. The rest of the book is devoted to abstracts of work in progress or recently completed. A list of the authors and titles of these articles will give an idea of the number of investigators in the department, along with the nature and scope of the problems being covered: B. E. Livinc- E.E. FREE, The effects of deficient soil oxygen on the roots of higher ihau _E. E. Free, The effect of aeration on the growth of buckwheat in water cul-_ tures; Symptoms of ‘Poisoning by certain n elements i oa Pelargomans pad chet se, Th 1917] CURRENT LITERATURE 169 ganic salt relations of plants, and relation of plants to climatic conditions. A quotation from the book expresses the point of view under which the work of the moiassaas ie is wing conducted. summarize e last age Paragraphs, our operations have been and are ae toward ad The point of view here employed may perhaps be envisaged if the reader will an the living plant in somewhat the same general way as he might any complex machine, such as a gasoline motor, for example. To understand its aera one must understand how and how much to be engineering science as applied to the living plant. It can progress, then, only through quantitative studies, through the comparison of efficiency graphs and curve- tracings made by recording instruments, through the mathematical interpretation of relations between conditions and process rates, etc., and it is with agg this sort of studies that our investigations have to do. It might be well if scientific d t g lly issued such statements of their aims —_ progress.—WM. CROCKER. NOTES FOR STUDENTS Rhizoctonia.—In a paper constituting a continuati Sf hie satin the genus Rhizoctonia, ErtKsson? adds. an account of two further forms, R. Medicaginis DC. and R. Asparagi Fuckel. The paper deals largely with historical and descriptive matter; the chief interest, ; questions relating to the taxonomy and id morphology of ‘th the Tut Do BP iadi-ncins Hance f the pha of the geminata Lo ue bs iting stage an calor fis < ic which he Had doxbs = 2 ca 170 BOTANICAL GAZETTE [AUGUST root-felt fungus found on crocus, alfalfa, and many other hosts (of which 54 are listed by him) belong to a single species, to which the name Rhizoctonia crocorum (Pers.) DC. must be applied as long as the fruiting stage remains unknown. This view is based upon a critical examination of the data in the literature and an extensive study of living material and herbarium specimens. He regards the evidence thus far presented as insufficient for the identification of the perfect stage of the fungus. Unlike Errxsson, he finds no resemblance between the mycelium cached by spores of Leptosphaeria circinans which he germinated and the hyphae of R. crocorum. Duccar further gives an account of Rhizoctonia Solani Kiihn, which is the more common of the two species in America where it is the widespread cause of “damping off” of seedlings and cuttings and root-rot of various crops. This species is clearly differentiated from the violet Rhizoctonia by characteristics of the mycelium and the sclerotia, as well as by the effects produced on the host plants. Fur- thermore, evidence seems to be sufficient that the perfect stage of this organ- ism is Corticium vagum B. and C. In a later paper,‘ as a result of a study of the data in the literature, this fungus is identified with the “‘ Vermehrungs- pilz” common in the seed beds and cutting beds of Germany and France, and also with the ‘ Mopopilz,” causing considerable damage to the seed beds of cinchona in Java. The failure to recognize Rhizoctonia Solani as the general cause of the “damping off” of seedlings in Germany and France, as well as in Java, is attributable to wrong determinations of the European seed bed fungus and the cinchona fungus of Java. g diff, i by D between Rhi ton is Sean 2 ye * Soe Pt, ae an i a ee es while R. : _ crocorum had not, up to that time, been successfully grown. Recently, however, DreHts reports successful cultures of the fungus from detached _ masses of mycelium. he cg lgishome plone aurea instance was a pure culture 0 ® on of th ic Rhizoctonias of the United States eek ee The chief features of the — report are (x) a general historical account, (2) a discussion of the oe so = 1 a the data relating to the hosts, occur ce rence, and distribution of R. Solani and R. ie ne tin i ome other countries, OTe a 1 e induce by these fungi in different plants, (3) eke calle a aa “Deccan, 2 B. Me Rhisctonia ‘Solani in teladion to the “Mopopile” and mae ’ Verm eh Sp a 916. os e of | ee ES tee 1917] CURRENT LITERATURE 17t cross-infection experiments with R. Solani, and (6) a description of the growth of this fungus in various media. The numerous cross-infection experiments carried out with Rhizoctonia Solani are of special interest. Strains of the fungus from some 30 species plants were used to infect carnations in several stages of growth, from the cutting to the mature plant, both under glass and in the field. A number of other plants also were infected with various strains of Rhizoctonia. The results of all these cross-infection experiments can best be stated in the author’s own words: “From these inoculation experiments with a large number of different types of plants, we must conclude that all the strains studied, which were obtained from a wide age of hosts ee dives gecprsplucst origin, can attack the No marked specialization was noted in any of the strains. Thus, all the strains studied can be included under one form, Rhizoctonia Solani Kiihn. The inoculation experiments show further that the virulence of R. Solani is very variable, as is also the degree of resistance of the various host plants, both depending upon a number of factors.” A study of the growth characteristics confirmed this general conclusion. Strains isolated from the same host species showed differences as great as those between strains isolated from different species. Matz? has described a form of Rhizoctonia occurring on the leaves and stems of Ficus Carica at Gainesville, Florida. This form is regarded by him as a distinct species, R. microsclerotia Matz. Aside from its foliicolous habit, ae te oe ee ee also capable of infecting fig leaves, without prod however single ya fe Seat Bera eee rie while -HASSELBRING. eo R. Soi pee ee o™, + ee ee : 3 ~— 66 oe ee L eae - ae : 1 i? 5 fee twtise Pee th ty reported rig Say lpn romng arrnt oy rgen bulge seen Ld in cited. The most complete of these earlier lists is that of TiscHLEeR (Pro-_ gressus Rei Botanicae 64-284. 1915). IsHrKawa’ has compiled the most 5:1 aes ever published, and in in each case has cited the authority. Besides, 172 BOTANICAL GAZETTE [AUGUST estimate rather than an.exact count. All of the Myxomycetes show 8 as the x number; in the diatoms only 3 genera are cited, the x numbers being 4, 8, and 64, the latter with 128 as the 2x number; in the Conjugatae 12 is the prevailing number, and in most cases the 2x is not cited; in the Chlorophyceae the x numbers are various, ranging from 6 to 32, but no 2x numbers are given; in the Phaeophyceae the x numbers are 16, 18, 22, 24, and 32, with the expected 2x numbers; in Characeae the x numbers are 21 and 16, but no 2x numbers are cited; in Rhodophyceae 8 forms are given, with x numbers ranging from 7 to 24 and with the corresponding 2x numbers. In the fungi the numbers are low and the 2x numbers are given in comparatively few cases; the minimum + number is 2, and it has been noted in 2 species; 4 appears in 24 species; few have more than 8 as the x secsebiiigg and ae maximum number (16) is cited in 6 cases. In the bryophytes 8 ber, having been noted in 12 species, while 4 has been counted i in S species, and Lag in one case and 6 in another. The all cases. - oa the x number ranges from 6 to 24, with 6 ( conited tat species) number. In the pteridophytes the numbers are comparatively high, the x number ranging from 4 to 120, and 24 of the 35 species cited have 32 or more, while only one (Salvinia) shows the minimum number. In the gymnosperms 12 and 24 have appeared so constantly as the x and 2x numbers that any other countings need to be very thoroughly ‘supported; 34 species with 12 as the x number are cited, and 3 which known to have 12, ‘Deck there aie 15) 6 necies is which the seuer § he oot been disputed. Otter tipabers are 6, 10, and 16. okies aman Ree: 28 are devoted to angiosperms. 3 in Crep | to 45 in Chrysanthemum arcticum. Tick ce Gece take oa ” ledons than in monocotyledons, and the most frequent + numbers are 8, 12, and 16. — ‘he lists valuable not only forthe systematically arranged citations of one marae 2 the c erate which the chrome apps ter 8 - CH AMBERLAIN, : : ;: sit Se SET | feature CHARLES : ¥ ig, uae : 1917] CURRENT LITERATURE 173 by shorter periods of darkness and light. Humidity of the air was figured to a standard. Potometer determination of stomatal aperture involves mass movement of air through the stomates under differential pressure, while transpiration involves static diffusion of water- vapor through the stomates. To clear up the physics of the problem, DARWIN gives two quotations from Sir J. Larmor: “The speed of diffusion through a narrow aperture between two open spaces . is proportional to its diameter. The speed of a stream of air through such an aperture, between open spaces having different pressures on them, is propor- tional to its area if the effect of viscosity can be neglected, but proportional to the 4 power of its area if viscosity is — Which of these conditions prevails, or whether the circumstances intermediate, in a given case, depends upon the diameter of the mem ca de “Diffusio n through a long pipe or channel varies as the area, and flow through it depends upon a reduced area owing to the flowing air adhering to the walls of the tube; in fact it varies as the square of the area if viscosity is predominant. Thus if this be the case, -provided the channels are of fairly uniform width, transpiration would be _ portional to the square root of flow, the same law as that obtained for the case of holes in a thin plate.” Darwin b th t nearly represents the situation, for the first applies only to tubes whose lengths are less than one-fifth of their diameter. As might be deduced from either of the physica eigrag y zl. at L skh l ) root of the rate of potometer flow, and another by plotting the rate of trans- Piration for various stomatal apertures, and for 18 separate experiments finds _ RS tcl aah acai although there are many minor dis- . temperature and 1 hum conten, which might go far to eliminate r minor were not carried out in closely controlled — . "abo a in explaining these discrepancies. ‘Much has been done since 1900 to ee the air nnon Put the material and a -antien peigeopi sityecleigarighn step in that direction. mes a 174 BOTANICAL GAZETTE [AUGUST planned so as to include 3 series of experiments. In the first series samples — of freshly dug potatoes were collected and cut lengthwise aba two equal parts. One set of the samples was used immediately for the d of moisture, sugar, and starch. The corresponding halves were divided into 3 sets and each set stored at a different temperature for 12 days before similar determinations were made. The samples were stored at 30, 15.5, and 5°C. For a checka number of whole potatoes were subjected to the same conditions. The second series was a duplicate of the first, except that the potatoes were dug about 2 weeks later. This series would show any change occurring in the growing potatoes after the first series was harvested. The third series of experiments was modified so as to determine the effect of removal of the vines on the carbo- hydrate transformations. The roots were not harvested until 10 days after a killing frost. HASSELBRING and HAWKINS pointed out that t to the rate of carbohydrate transformations in stored sweet potatoes the Van’t Hoff temperature law was applicable. In general, at 30° C. starch hydrolysis was rapid at first and soon reached an end point. At 15°5 C. a more normal rate of transformation took place, tending toward a state of completion. The hydrolysis at 5° C. was markedly retarded. In spite of the utilization of reducing sugar in respiration, HasSELBRING and Hawxrys were able to show a marked accumulation at first and very Bite ——— accumulation. The concentration of the F y luring the p Storage: ‘There w: was a a lagi in iais bi ease chee accel with the increase of reducing sugar. The data suggested that the mode of carbohydrate trans- : formation in stored sweet potatoes was from starch to reducing sugar, which resulted in the formation of cane sugar as the end product. On studying the effect of eee it was found that during their activity the sugar content remained low. As as checked by removal of the vines, the usual f . bo 4 a. fcwcts ‘potatoes manifested themselves. ; es _HASSELB SSELBRING and Hawkins" have coused out that tbe internal changes ; storage must play an important réle in susceptibility to decay. Aside poe the theseetical Uipnificance, it seems that this mode of attack on storage " Problems of this nature will be of economic value—Frep W. GEISE. a _ Taxonomic selon SarsTO = in continuation of his studies of West a | en @, Passifora @), Rondeletia (10), Eriocaulon G)» Dupatya, Pilea, — Ichthyomet} , Castelaria, and Stenostomum | 2). a 1917] CURRENT LITERATURE 175 Fawcett and RENDLE™ have described new species of Tephrosia, Cassia, and Erythroxylum from Jamaica GaTeEs* has described a new species of Oenothera (O. novae-scotiae) from Nova Scotia. It is related to O. muricata, but is distinct in leaf, stem, and bud characters, especially as to pigments. The species was studied in con- nection with the germination of 1000 of its seeds. GREENMAN,® in continuation of his studies of Senecio, has preted § AurEI. The section includes 48 species, 5 of which are new, the descriptions being accompanied by a full bibliography and liberal citations of exsiccatae, espe such as occur in American herbaria. The same author" has also described a new vinelike Senecio (S. Hollickii) from Jamaica, collected by Britton and Hottick in 1908. Miss Hitt has described a new species of Spirogyra colened: in the basin of an old fountain in Seattle, Wash. It is named S. gigantica on account of its size, the filaments being 173-188 » in diameter, the cells being 1-2 diameters long, and with 4-6 chloroplasts. It most nearly resembles S. crassa. Husparp® has described a new species of A gropyron (A. acadiense) from Cape Breton, Nova Scotia, rates to A. Smithis Ryd. Naka,” plants of Japan and Corea, has described 15 new species in several genera, and proposes the following new MAL! OLIVE in connection with a study of the parasitic ie of Porto Rico, describe Botryorhi d Endophylloid 1ew genera, and also 4 species of Endophyll. as new nbinations, formerly referred t Aecidium. PRAEC 2t | Spann yin bie A a Bae | BORA yes ey GER, described 8 new speciea-J M. C. . awcerr, W., and Renpie, A. B., Notes on Jamaica plants. «Jour Baany : ne 1917. ee * GATES be, © nee eu ows, Trans, Nova Seoia Int, Sct 14: 141-145. ‘es 2. sai . *S GREENMAN, J. M | Moma of the Barth ed Conde A me ica n species - the genus Senecio. "Part I. Ann. Mo. Bot. Gard. 3: 85-194. bls. +5. be case 176 BOTANICAL GAZETTE [AUGUST Enzyme activity of fungi—With a view of ascertaining the manner of destruction of wood by Lenzites saepiaria, ZELLER” has made a general study of e enzymes in the mycelium and sporophores of that fungus. Enzyme preparations of the mycelium were made by extraction of dried and ground cultures of the fungus grown on sawdust. The enzyme mixture precipitated from the extract by means of alcohol was collected on filter paper and preserved Preparations from the fruit bodies were made in a similar manner. From the activities exhibited by the powder thus obtained, the author con- cludes that the following groups of enzymes are present in the mycelium and sporophores of Lenzites saepiaria: (1) of the esterases chiefly those affecting the hydrolysis of the esters of the lower fatty acids; (2) of the carbohydrases, maltase, invertase, raffinase, diastase, innulase, ligninase (by which the author designates CzAPEK’S “‘hadromase”’), cellulase, hemicellulase, and pectinase; (3) of other enzymes, emulsin, tannase, urease, hippuricase, nuclease, pro- teinases, rennttase, oxidase, and catalase. £. aot Tot anc ‘containing a gradually increasing percentage of resin, growth was only slighty depressed in Pa i cent of resin. In emuls' over 50 per cent of resin growth is sharply depressed, while in ‘ine containing over 85 per cent growth is practically inhibited —H. HAssELBRING. Texas root rot—Duccar* reports the finding of f a conidial stage of the " fungous diseases of the cotton crop. The conidia. se nidia-bearing hyphae usually occur in patches on the bare ground between the rows of plants and only rarely in connection with the roots themselves. They are borne on swollen or club-— : shaped branches recalling the conidiophores of some species of Botrytis. The spore powder which covers the ground of the fertile — is ee bull. es ie yphomycete genus Phys ichum as P. omnicorum (Shear) Duggar. ea oe equation of Long IandHsxr has pase tt ofthe plants : : ~ City. a will serve for comparison witl At cei’ is and as a abe : ce VOLUME LXIV NUMBER 3 ee BOTANICAL GAZETTE SEPTEMBER 1917 ROOT SYSTEMS OF CERTAIN DESERT PLANTS CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 236 M. S. MARKLE (WITH THIRTY-THREE FIGURES) Introduction Although the aerial parts of plants have leng been studied, little was known of the nature of the subterranean parts until the work of CanNon' upon the plants of the region about Tucson, Arizona. The sup position had been that in general the roots of desert plants are of g enetratic The work ee of CANNON showed ‘that while this this is is so tim true, st : : a : : oe ee area att, ‘ 1 length oe al ike weh SPL SAS Since the soil conditions and the flora of the vicinity ‘of Albu- — querque are different from those at Tucson, a study of the rootsof = ‘Plants was undertaken in that vicinity, during the first half of f the e “year FOr, Divers incre lies i in | the steses of the sees ey ule, on - : very d dry. 178 BOTANICAL GAZETTE [SEPTEMBER concluded from this that previous to the deposition of these beds there was here a deep trough, which other evidence shows to have been the bed of a large river, which existed at a period of greater precipitation and was subsequently filled with stream-borne material. On account of its fluviatile origin the material is extremely variable, being composed of layers of sand, adobe, clay, gravel, boulders, and combinations of these materials, with marked local variations, both horizontally and vertically. On this mesa and the numerous arroyos which dissect its edge grew the plants studied. One of the principal features of the soil in the habitats described by CANNON is a thick layer of hardpan, or caliche, beginning at a depth of about 30 cm. and extending indefinitely. This is so hard as to prevent root penetration, except through cracks. Such layers are common in arid regions, and are formed, according to the opinion of CANNON and others, through the concentration of salts left by the evaporation of ground water gradually ascending by capillarity. Rainfall dissolves these materials, carrying them downward. These two processes result in the formation of a gradually increasing zone of precipitation. In the Albuquerque region this zone is very poorly developed, often being noticeable in a fresh exposure only by the presence of a whitish streak or pebbles stained with lime. When dry, such soil becomes very hard, and it is evident from the appearance of roots entering it that it offers considerable resistance to root penetration, but does not prevent it. When wet the hardpan is soft and easily _ penetrable. — natural conditions, however, it is generally is | | arid than that at Tucson, ~ = 4 an average fic 10 years | giving a precipitation of 7.44 in., as com- 3 pared with an average of 11.17 for. Tucson. Much of this small “rains in the summer oe tes ones ———: from. the : “summer rains. a i a 1917] MARKLE—ROOT SYSTEMS 179 months prevent the growth of the winter annuals so characteristic of the Tucson region. TABLE I RAINFALL Jan. | Feb. | Mar.| April) May | June | July | Aug. Sent, Oct. | Nov. | Dec. | Total Tucson. ... 79|0.90/0.77/0.27\0.14/0. 26|2.46|2.66|1.16/0.64/0.81|1.00|/11.17 Albuquerque, average... . 0.4810. 33/0. 22/0. 26/0.69/0.35|1.43|/1-07|1.70|0.77/0.46) 31 | 7-44 Albuquerque, TORRE 0.68]0. 56/0. 51/2.05/0.00|0:00) eS Ares ae ee TEMPERATURE | x803 | s808 | 180s | 1896 | 807 | 2808 | 3800 | 1000 root | 902 minimum II Ol 3) M41. 3 ° ee 4{| 42 Absolute maximum 98 | 95 | 95] 100 | 95 | 104 | 104 | I0r | 99 | 100 EVAPORATION FROM A FREE WATER SURFACE a caienl a pie ae fapestl 73] 1.49 - The data for Tucson are rc i pila ree wid “MacDoven = 2 soon found that such data are of little value, since on account of the fact that the soil is composed of stream-borne material, it is. subject to extreme local variations, even within the habitat of a ‘single plant, as is shown in th iptions of the habitats of most _ -h nitions | _ of the plants given in this paper. "Samples of soil from different — ee | levels in the habitat of forces canescens showed the ane : rs oe 180 BOTANICAL GAZETTE [SEPTEMBER several times the normal amount, the figures would have had even less value than usual. Similar variations in water holding capacity and wilting coefficient would result from the lack of uniformity in the soil. On account of climatic differences, the flora is very different from that of the Tucson region. The larger cacti are absent here, all being low forms, excepting Opuntia arborescens. No tree is found on the mesa or its arroyos, and the bushes, except Chilopsis saligna, are seldom more than 5 ft. in height. The period of greatest growth follows the rainy season, whenever it may occur. There are no winter annuals here, the corresponding forms being either biennials or summer annuals. The annual plants are greatly in the minority, the most conspicuous part of the flora being composed of perennial herbs. The principal plant associations occurring within the area ane are as follows. . The Penton: association, _chaeactenized by the grama and | sees , but now much : invaded by ruderals, such as xs Cakes Scvothrae and Salsola. 2. The Dysodia-Ephedra association, dominated by Ephedra ietjores and Dysodia acerosum. The majority of the plants have reduced aerial parts and a large root system. The association occupies the top and the upper portion of the sides of the gravelly oe -tidges between the arroyos, where exposure and run-off are maxi- : ae mum. The soil is atte Pee gravel and ne 8 surface is generally a oo es The Ch : th Pee 4 oe Pies by Chrysothamnus si : _— Bigelovii and occupying the stare of the sides of the antes a The soil 3 is generally adobe, often d and gravel. tnd form eae ‘a. narrow fringe along the beds of arroy0s, which are = mle sired wi ke ane tos : : association, dominated by Fallugia poradoxa - 1917] MARKLE—ROOT SYSTEMS 181 many are necessarily incomplete. It was found possible to photo- graph some of the larger perennials zm situ, but in general it was found much more satisfactory to make accurate diagrams of the horizontal and vertical extensions of the root systems on paper metrically ruled in squares. The diagrams appear here drawn toa scale of 1:20, except figs. 25 and 26. While in general only the roots lying in or near a particular plane are represented, it was generally found possible without much distortion to include the most important part of each root system in both the horizontal and vertical diagrams. Roots that for some reason were not followed to the end are terminated in the diagrams by a broken line. Roots turning to a direction at right — to the ne of the diagram end in a dot. CANNON divides root cians into 3 types: (1) a generalized type, in which there is a well balanced development of both tap and lateral roots; (2) a specialized form, in which the tap root is -™Much the more prominent; and (3) a second specialized form, characterized by a relatively better development of the lateral roots. ee ; 5 insta That age dents . Becetelle Wislizeni-—This lant a ee eS oe : om the mets and to the actoyes. = consists of relatively short tap root, with many strongly developed laterals horizontally rather near the surface of the ‘soil. Some ae of hens usually exceed the tap root in length. The specimen — en “oes I fe dt in ene gener ae an cI in . 182 BOTANICAL GAZETTE [SEPTEMBER shown in fig. 2 grew in a moist situation, where the water of an arroyo was impounded by adam. The plant is in its early spring condition, the rosette having survived the winter. The root system is of the generalized type. The laterals near the surface are especially well developed, sometimes exceeding the tap root in length. The specimen shown in fig. 3 is from a dry, gravelly ridge in the Dysodia-Ephedra association. The impoverished condition of the plant is shown by the weak development of both root and shoot. Here the tap root is relatively the more important. Allocarya crassisepala.—This is one of the most common annuals of the mesa and arroyos and is a ruderal in a number of associations. The plants vary very greatly with the soil conditions in both root and shoot. The plant shown in fig. 4 grew in moist soil in the bottom of an arroyo and bore numerous prostrate branches. The root system was superficial and consisted of a short tap root which soon “Fic. Biscutella Wislizeni «became horizontal, and - number of long, b laterals arising about an inch below the surface of the soil. The ‘plant shown in fig. 5 grew in dry soil and had a tap root relatively = "hig a: and vertical, with poeta and less numerous canescens. —This plant i is common ina number of a 1917] MARKLE—ROOT SYSTEMS 183 Linum rigidum.—This plant is characteristic of the Dysodia- Ephedra association. Both root and shoot are much reduced. The root system in the plant shown in fig. 7 consisted of a tap root about 5 in. long and a few short laterals with almost no fine ultimate branches. 184 BOTANICAL GAZETTE [SEPTEMBER which later are deciduous. These always break off upon removal from the soil and do not appear in the figure. Rumex hymenosepalus.—This plant is common in the more mesophytic places on the mesa, especially in broad, shallow arroyos. The rosette of broad, thick leaves appears very early in the spring and is soon followed by a spike of flowers. The root is very large 1917] MARKLE—ROOT SYSTEMS 185 Rumex is common in the arroyos on the mesa; Cucurbita foetidissima occurs most abundantly along the banks of irrigation ditches in the valley; Berlandiera lyrata is confined almost entirely to the sides of arroyo beds. Thus it appears that the plants having this “adaptation” to an arid environment are in less need of it than most of the plants of the region. Fics. 6, 7.—Fig. 6, Sisymbrium canescens; fig. 7, Linum rigidum Astragalus diphysus and A. mollissimus——These are common €vergreen plants of the mesa. The root systems are similar and are characterized by prominent tap roots with a few large and several small laterals, which are generally deeply placed. The root tubercles are small and not numerous. A ae of A. mollissimus a is shown in fig. 10. eS Solanum eleagnifolium. This plant is very characteristic i ae - sandy situations and the oS ee sides of arroyos. te 186 BOTANICAL GAZETTE [SEPTEMBER plant shown in fig. 11 grew in the latter situation. The upper 12 in. of soil was sandy adobe, followed by 10 in. of clayey adobe with some gravel. Below this was a layer of loose gravel about 2 in. in ickness, under which was fine sand to an unknown depth. The plant was 18 in. in height. The root system was of the specialized type with strongly developed tap root. There were a few well developed laterals, two of which arose at the junction of the layers of sandy and clayey adobe. Upon reaching the layer of loose gravel, one of these turned abruptly and proceeded hori- zontally in the gravel layer, possibly tortuous course downward and was lost at a depth of 65 in., below the level 3 mm., its total length was undoubtedly - much greater. Numerous small laterals arose in the upper 12 i in of soll. Cucurbita foetidissima.—This per- - ennial herbaceous vine is common along irrigation ditches in the valley and less so along the sides of arroyo beds. The a i--Comiptone Fendleri_ root is extremely thick and fleshy and is surmounted by an underground stem 6 in, in length. The ais Wook of the ea since was wan ee 365) in. in diameter at the top and extended to a depth of 20 in., oe eg becoming horizontal and forking several times after . ing a length foe in. The main root bore only one small : ates (ig. 12). Pa s bus ~ ulus. This pai ten Babi ad is » ; d slopes of the gravelly 1917] MARKLE—ROOT SYSTEMS 187 irregular form, without evident differentiation into tap root and laterals. The main root often proceeds horizontally and is little larger than the minor roots. The specimen shown in fig. 13 grew in pure gravel. Euphorbia sp.—This small, prostrate plant grows on the sides of arroyo beds. The root system has much the same general form Fics. 9, 10.—Fig. 9, Rumex hymenosepalus; fig. 10, Astragalus mollissimus as that of Sphaeralcea, but all the roots are slendex, brown, and fibrous. The identity of the tap root is lost a short distance below S the surface. The slender ultimate branches are very numerous. The root system is not deep, but very ee | weareeeas 2. limited amount of soil hei. |: vs __ Sphaeralcea cuspidata.—This plant is very | comr Or Bouteloua and pees edra associations. The plant 188 BOTANICAL GAZETTE [SEPTEMBER fig. 15 grew in sandy soil on the mesa. The root system is charac- terized by a tap root which is poorly differentiated or even absent, and very prominent laterals. The remains of the crowns of several years are shown. When the plant grows in an unstable situation, Vv __ such as the rapidly eroding side of an arroyo, vegetative reproduction from the roots occurs very commonly, enabling the plant to maintain a foothold. Berlandiera lyrata—This plant is confined almost entirely to the sides of arroyo beds. The root system has a stout tap root with very few laterals. The group of laterals near the surface of the ground in so many plants of the region is absent here. The entire root system is thick and fleshy and the upper portion is swollen to the thickness of an inch. Plant A, fig. 16, grew about 1 it. _ above the bed of anarroyo. The tap _ root divided into two horizontal ~ _ branches slightly below the level of ie arroyo bed. Plant B grew about 4 ft. above the bed of an arroyo and bore no extensive laterals until it _ reached the level of the bed of the \ arroyo, where it branched freely. 1 i - cei of the re root is — cg : tance to - the layer of n moister soil Oe . 1917] MARKLE—ROOT SYSTEMS 189 the absorption probably being done by the ultimate branches of the tap root. Vegetative reproduction from the roots is common (fig. 17). 12 i Fics. 12, 13.—Fig. 12, ertical ext 7 £ + cf. ee a re . fig. 13, vertical extension on of root system of Packylophus hirsutus mew em ee ee eee ee ee eee Se alietnettadt tt ie at ae aed aS ee wer ee ee Igo BOTANICAL GAZETTE [SEPTEMBER cactus type. Insome specimens no tap root could be distinguished, although a better development of the tap root was found in plants 16 ; 17 _ Fics. 16, ie 16, vertical extension of plants of Berlandiera lyrata: sical growing 1 ft. above arro yo bed; 2. Singha above arroyo bed; fig. 17, —— ee ee = Oe a a ee i 1917] Fic. 19.—Vertical and horizontal MARKLE—ROOT SYSTEMS en] -_-2e77 7" =--°>" ted --"" -* -* one? Fic. 20.—Root system of Ephedra trifurca 192 BOTANICAL GAZETTE [SEPTEMBER was 28 in. in height. The tap root was weak, being exceeded in diameter by several of the laterals. The laterals were numerous and arose just below the ground and proceeded horizontally 2 or 3 in. below the surface, most of them beneath the bed of the arroyo. The ends of several of them dipped abruptly downward. This type of root is rare in the region. The root system of Parosela scoparia, which grows in sand, was found to be similar, but more deeply placed. Artemisia tridentata. —This plant grows along the sides of arroyos in the Chryso- thamnus association. Well developed speci- mens are rare, since the plant is freely eaten by grazing ani- mals. The specimen shown in fig. 19 grew in soil the upper 10 in. of which was adobe, overlying 12 in. of coarse gravel and Fic. 21.—Root system of Dysodia acerosum oped, but the laterals near the surface were extremely prominent. These were of two types: numerous short ones in the upper 12 in. of soil, and a few very long ones which arose from the upper 6 in. of the taproot. The latter proceeded horizontally 3—4 in. below the surface of the soil and reached a length of 20-40in. There was a tendency for the ends of these roots to turn downward, as in Parosela. Ephedra trifurca.—This is one of the dominant species of the _ Dysodia-Ephedra association. Investigation of a number of Oe Se te om, 1917] MARKLE—ROOT SYSTEMS 193 specimens showed a considerable variation in the root system, which in general has a good development of both tap and lateral roots. The plant shown in fig. 20 grew in adobe soil about 2 ft. above the bottom of an arroyo and had prominent laterals and a stout but rapidly tapering tap root. Below the part shown in the photograph, two large laterals were given off, below which the tap root was insig- nificant. Another specimen growing in adobe soil to ft. above the bottom of an arroyo and ex- posed by erosion showed a relatively much greater de- tap root. Several laterals, the largest alf an inch in dia- meter, were given off in the upper 2 ft. of soil. Three small laterals occurred 3 ft. below the sur- face. The tap root proceeded somewhat tortuously down- : a ' ward to a depth of Fic. 22.—Root system of Chrysothamnus Bigelovit at least 11 ft., a little below the level of the arroyo bed, where a large lateral arose. Below this the tap root had a diameter of 5 mm. and was not followed farther. A third specimen grew ona hill and was exposed by the removal of gravel. The plant grew in a soil composed of boulders up to 8 in. in diameter, the interstices of which were a : filled with sand. The root system was essentially similar to ie second specimen described. The cause of the variation in the = i appa ney is not t the c character of 194 BOTANICAL GAZETTE [SEPTEMBER but the height of the plant above the nearest arroyo. Even though there is a stream in the arroyo only a few hours each year, there is probably a layer of moister soil on a level with the bottom of the arroyo, on account of a slow creep of ground water toward the arroyo and the conservation of the moisture by the dry sand covering it. Dysodia acerosum.— The habitat of this plant is the same as that of Ephedra. The aerial parts of the plant form a compact, much- branched tuft. The leaves are needle-like. The individual photo- graphed grew in sandy adobe with large pebbles (fig. 21). The plant had a stout tap root with a few large laterals arising close together a short distance below the surface of the soil. The tap root shown meas- ures 39 in., but it was probably several inches aie longer. Both tap and Fic. 23.—Root system of Opuntia fragilis lateral roots bore numerous fine branches. This species probably has the largest root system in proportion to the size of the aerial parts of any of the plants of the region. Chrysothamnus Bigelovii—This is the dominant plant in an association characteristic of the lower parts of the sides of arroyos. The principal photosynthetic work is done by the almost leafless green stems. The root system is of the ne type. Fig. 22 shows only a part of the root system of a rath Later excavation showed laterals up to go and 100 in. ». in length and a tap : - root about roo in. ae eee te 1917] MARKLE—ROOT SYSTEMS 195 and taper very slightly and bear numerous small lateral branches, especially near their distal ends. Older individuals probably have root systems more extensive than that of any other plant of the arroyos Or mesa. , Opuntia fragilis.—This is the smallest and most common cactus of the mesa, where large colonies form mounds of sand or adobe. The root system is very superficial and con- sists of one or two Main roots with numerous small lateral branches (fig. 23). Opuntia arbor- escens.—This is the only large cactus found in the region. mountains and ‘occurs sparingly See ek a dae ee Ok ie specimen shown in ia rae e figs. 24 and 25 grew in the latter situation and was only 2.5 ft. i root system is similar to the type described by ( larger forms occurring near Tucson. There i is a shar tion of absorptive and anchorage roots. The forn and thin and occur within an inch or two of the 196 BOTANICAL GAZETTE [SEPTEMBER Opuntia camanchica.—This is the common prickly pear of the mesa and arroyos. The specimen shown in fig. 26 occurred in the Dysodia-Ephedra association in gravelly sand with small boulders. The plant had been formed vegetatively from a fallen segment which had become buried. The roots had originated from the pulvini and the proximal 2 inches of each was tuberous. The root system conforms to the usual superficial type described by CANNON for the smaller cacti, except for the presence of one thick, deeply * placed root. The plant is usually several joints in height, so that Fic. 25- Ak tt +f ‘of Opuntia arborescens, } + tal extension -_ -— _ joint. The asic tah the thicke ,m placed d root may a 1917] MARKLE—ROOT SYSTEMS 197 formed by vegetative multiplication. The root system consists of a thick, branched, horizontal portion bearing numerous laterals quite uniformly about 3 mm. in diameter. Those measured showed lengths of 5,6, 7, and 24in. The main root is usually about 2 in. in diameter and very succulent. It evidently functions as a- storage organ. 198 BOTANICAL GAZETTE . [SEPTEMBER confined almost entirely to the space between the 16 and 24 in. depths. The effect of the position of the plant with reference to the arroyo bed is shown here. Gutierrezia Sarothrae——This semi-evergreen shrub is a common ruderal in many associations of mesa, mountain, and valley, but especially on the mesa, where grazing has been a greater disturbing factor. The plant shown in the photograph grew near the bottom of an arroyo and had a root system of the generalized type. The Fic. 27.—Yucca glauca plant shown in the diagrams was a small specimen 8 in. in height and grew near the edge of the steep bank of anarroyo bed. The tap root was especially well developed and extended vertically to a depth of 44 in., where it reached the level of the bottom of the arroyo. Here the tap root turned and extended out under the bed of the arroyo a distance of roo in., branching freely. The horizontal part of the root was within 2 in. of the surface and bore numerous fine absorptive roots. It is evident that the unusual development of this root system is a response to moisture conditions, and it is doubtless to this ability to respond to varying conditions that 1917] MARKLE—ROOT SYSTEMS 199 the plant owes its success as a ruderal in so many associations (figs. 29, 30). Atriplex canescens.—This evergreen shrub is common on the fans at the mouths of arroyos and less so along the sides of the smaller arroyos. A small plant 18 in. in height and growing in a small arroyo was selected for excavation. The upper 15 in. of the soil was sandy adobe, underlaid by 32 in. of coarse sand and gravel and 15 in. of hardpan. The plant had a strong tap root which forked at a depth of 32 in. One branch continued vertically downward and penetrated the hardpan layer. The other branch Ais mwweeeen ww +e ee we we ee ee ee ee cee eee te tee ede cece weet ts ee Cs) eae eek we ee pe 2 ee 8 oe Fic. 28 a, 7 Se ee, een * - 4 me ff oT. wo. . le j root penetration was evident fom the twisted character of the ) fonts es 32; 32, 33): os : (|. dycum pallidum.—This solana eo — [ane Heiiho ee mie TOY oye yo 200 BOTANICAL GAZETTE [SEPTEMBER A few laterals may extend upward. The main root of a specimen 18 in. in height was followed along the face of a steep bank for a distance of 15 ft., at which point the root was a quarter of an inch in diameter. The superficial character of the root system makes possible the vegetative multiplication by which the plant maintains itself in its unstable habitat. Erosion exposes the roots, which , put forth new shoots. Discussion On account of the fact that here, where the soil is of fluviatile origin, the conditions to which roots are exposed vary so much, — even within the habitat determine. Variations are common, but they may be due to one or more of a large number of soil factors, such as the composition of the soil, its penetrability, ‘Fic. 29-—Galierrezia Sarothae from near bottom its alkalinity, its wilt- : . : of arroyo. ing coefficient, etc. roe problem of the causes of root variation is one to be attacked lition: ssa huasasic one factor can be varied at : ne Pees ane made apparent the effect of at least two a 1917] MARKLE—ROOT SYSTEMS 201 eleagnifolium, shown in fig. 11. A layer of soil difficult of penetra- tion may cause much distortion of roots entering it, as seen in the diagram illustrating the roots of Atriplex canescens. The most striking instance of the effect of a variation in the water content of the soil is shown in the roots of plants growing along arroyos. Nearly all of these are characterized by long tap roots, the length of which apparently is determined by the height of the base of the plant above the moister soil below the level of the i i <. e G See tT mms, s, ‘ ' ' ' ' Mo mee : ie ec et “S cy pete tae ae, - . ec. nas me ge ot : Fic. iG. 30. 5) pee Y y Career Se 202 BOTANICAL GAZETTE [SEPTEMBER the widest distribution, while those with the specialized types are confined to peculiar habitats. Gutierrezia Sarothrae, which has a generalized root system, is very widely distributed in primitive growths and as a ruderal. A number of species are confined here to the sides of arroyo beds and are characterized by prominent tap roots. Lycium pallidum has prominent horizontal roots and is confined almost entirely to rapidly eroding banks. he ee em ee we on - Oe ay : > : ~—=F : a - iy : XT. 4 . : —s 31. rt y =e. 5 oe ey ate. © gens cred, ; Contrary to what _ the most fleshy roots grow in situpiions s better watered than the average. Cucurbita foetidissima grows near irrigation ditches and _ along arroyos; -Rumex hymenosepalus occurs in the broad arroyoS a ‘crossing the mesa; Berlandiera i is esas almost entirely to the i me fe =) wy. 1917} MARKLE—ROOT SYSTEMS 203 is very prominent. A comparable adjustment of the roots of plants with reference to soil moisture probably exists in all types of associations, but especially in arid habitats soil moisture is a limiting factor and root competition is more severe. Observations of the distribution of the roots of some of the associations were made on rapidly eroding arroyo banks and sand and gravel pits. In the Bouteloua association, the most superficial layer of roots is that formed by the grasses, principal among which are Bouteloua ertopoda and Hilaria Jamesii. Most of the roots of these grasses occupy the upper 2 in. of soil, although some of them go much deeper. The roots of Hilaria are very tough and woody and reach a length of 6 ft. or more. The thorough permeation of the upper Fics. vit ss Fe 3% horizontal extension of root System of rie canescens at depth of ele A eae a aN for the relatively pure growth of grasses in this association. They so thoroughly remove the water from the superficial layer that seedlings of deeper rooted Plants perish before the lower, moister a _ layers are penetrated. Over larg ae Sg ke aS eT BEI : ruderals ane £7..85 ih the Dysodia-E phedra association, th 204. BOTANICAL GAZETTE [SEPTEMBER A second region of root penetration is occupied by the relatively superficial laterals so common among the plants of the region. These in general are more deeply placed than the roots of the grasses and annuals. Dysodia acerosum, Aplopappus, Euphorbia, and Hymenopappus are the principal plants. ' A third layer of roots is made up of the lateral roots of Ephedra and the deeper parts of the root systems of Dysodia, Allocarya Jamesii, Pachylophus hirsutus, Melampodium, and others. The fourth layer probably does not always occur, but near an arroyo it may contain more roots than any except the superficial layer. Here occur the ultimate branches of the tap root of Ephedra, Gaura coccinea, Berlandiera lyrata, Stephanomeria runcinata, and others. The zonation of the roots reduces competition and permits the growth of a larger number of species. The root systems of the two dominant plants compete but little, since the principal absorptive roots of Dysodia occur in the third layer and those of Ephedra in the third and fourth layers. This no doubt accounts for the joint dominance of the two plants. Th t Albuqu liffers from that of Thaceoetin havind aboek two-thirds as much rainfall and much lower winter tempera- tures. ‘The soil of the mesa is fluviatile in origin and very _ diverse in composition. The hardpan layer prominent at Tucson — is not well developed. The winter annuals and the larger shrubs and cacti are absent. Most of the plants are sponses oa _ herbs. . "The root systems poms penetrate rather deeply, but often ae Mine prominent laterals near the surface of the soil. The cacti and oe afew ot fici: J root system. Thelarger— - u oS cacti show : a differentiation into anchorage and absorptive | eee Le 1917] MARKLE—ROOT SYSTEMS While the causes of root variation can be accurately duterntned: ‘only under anbaratory conditions, two factors exert s wey evident influence, content. oe The roots of the plants of association are grouped i definite layers, so » that root - competition i is lessened. The DEVELOPMENT OF SOME SPECIES OF PHOLIOTA W. H. Sawyer, Jr. (WITH PLATES XVI-Xx) The taxonomy of the Agaricaceae at the present time is based upon characters of the mature plant which in many cases are slight and superficial and of uncertain homology. It is very probable that a knowledge of the origin and method of development of the. different structures composing the mature fruit body would aid greatly in determining true relationships among the different genera and Species, a ig is for this reason that a comparative study of th lop t of the basidiocarp is important. The first serious study in the Agaricaceae of the origin and dif- _ ferentiation of the parts of the young fruit body began over half a century ago, when HorrMann (19), in 1856, briefly described the origin of the hymenium in Agaricus campesiris and two other _ species. Four years later HorFMANN (20) gave a brief account of _ the development of several additional species, in all of which the hymenium was : Sangrpons in origin except one, Marasmius oreades. - In 1866 D ¥ (13) studied the development of several species of Agaricaceae, and his work was followed in 1874 by HartIc’s (18) description of Armillaria mellea, BREFELD’s (12) work upon Coprinus in 1877, and in 1889 by Fayon’s (15) very cursory study of 43 species, with hymenium both exogenous and endogenous in : _ origin. Nothing more was done along this line of research until _ : 1906, when ATKINSON (2) published a thorough description of the os t of Age np A 1 the stimulus given by th : - 4%. ne evide Se ee 1 ee s by se ry eee Ee a : tions on the development of “different agarics, a cee = oe _ ALLEN (1), BEER (11), and FISCHER a (16). ee 8 = _Themateri forthe allowing investi 01 cc - 1917] SAW YER—PHOLIOTA 207 rotten coniferous wood, presumably Picea rubra. Material of all 3 species was very abundant in several different localities, and in each case the young stages selected were identified beyond the possibility of a doubt by mature specimens associated with them. An abundance of material in all stages of growth was fixed in Carnoy’s fluid and carried into cedar oil before returning to Ithaca, where it was imbedded, some in paraffin and some in collodion, and sectioned for study. Pholiota squarrosa Young fruit bodies, in the stage of development shown in fig. 1, are elliptical or elongate in outline and composed of hyphae loosely interwoven in the basal region, but more compact toward the apex, with some of the threads radiating from the summit. Scattered through the tissue of the fruit bodies are hyphal threads, somewhat straighter and more even in diameter than the ordinary hyphae, which are Cepines because of het property of inking a very deep stain. Thesed ly in the youngest basidiocarps, but in successive stages of riage and in all 3 species studied. Their function is unknown, but probably they serve some special purpose in nutritio ‘ les oe has been shown to occur in large q (Phallus, et al.) asa_ reserve food material, utilized during growth, ‘and it may be that > these peculiar threads owe their deep-staining sci ea to ced ) presence of this substance. - DIFFERENTIATION OF STEM FUNDAMENT. in the ‘frait bly shown in fig. 1 a small, deeply staining area occurs in the central and in ‘verve eal, the : ah apical Part; this i is a region of active penth, with ee a c fruit body. ‘This region marks | would i in all probability be pacary : fruit body,as shown in fig. 25 f ot peieinete 208 BOTANICAL GAZETTE [SEPTEMBER described in Lepiota cristata and L. seminuda (10), in species of Cortinarius (14), and in Rozites gongylophora (22). In further stages of development, the hyphae in the stem funda- ment, by interstitial growth, form a compact, broadly conical area, whose apex is the dark-stained region and whose sides in median longitudinal sections slope outward at a strong angle (fig. 8). The hyphae pursue a rather uniformly longitudinal direction of growth, and are rich in protoplasm; the peripheral threads, because of this longitudinal arrangement and their deeply staining qualities, delimit the surface of the stem from the enveloping ground tissue, whose hyphae are poor in protoplasmic content and without definite direction. DIFFERENTIATION OF HYMENOPHORE AND PILEUS PRIMORDIA.— During an early stage in the differentiation of the stem fundament there appears, in median longitudinal sections, in the ground tissue on either side of the apical part of the fundament, a small mass of hyphae, which is readily distinguishable from the surrounding tissue because of the compact nature of the hyphal complex and its property of taking a deep stain (figs. 4, 7). Serial longitudinal sections show that these hyphae occur in a ring around the apex _of the stem primordium; they are the earliest evidence of the dif- ferentiation of the primordium of the oo The appear- ance of th he fundament _ one: the pileus from the stem fundament, although as sae the tissue composing it is very loose and hardly to be distinguished from the _ a — ground tissue. The individual hyphae that make up i grow down from this area; at first = | | they are crowded, very rich in protoplasm, and run in every direc- ee 6). As = 4 , the — aor out nor i mo eve are slightly more slender, averaging abeat i917] SAWYER—PHOLIOTA 209 in the hymenophore are slender and somewhat pointed; they show a tendency to aggregate themselves at the tips into groups or tufts, with the ends of several hyphae in each tuft, and the different tufts separated by narrow interstices, so that the primordium often presents a rough and jagged appearance in this stage of its develop- ment. BLEMATOGEN.—In the youngest fruit body sectioned (fig. 1) the universal veil consists of hyphae which push up at the apex and turn downward in all directions. There is little doubt that if younger stages had been available for study, a condition would have been found similar to that in the very young fruit bodies of P. flammans, where the hyphae in the beginning are loose and radiate from all over the surface of the basidiocarp (fig. 24). In the stage shown here, however, the development has proceeded to a condition where the hyphae of the lateral surface of the fruit body have taken on a direction of growth parallel to the axis of the stem - fundament; a central core or strand of hyphal threads in the apex grow upward more rapidly than the surrounding tissue, and by curving backward and downward form a covering, which is the oe Over the entire surface of the fruit body. The hyphal — sei thus ¢ Sues ae outside become enlarged and ee : ae Poke ae POSTS ey ae are 3-5 u in diameter near the. base, and in —— region they — : the hyphae of the blematogen layer pie ee sees: dag . 8-15, # in diameter. The | cond dition anaepe here is Louie : gen, a8 shown in fig. 13. a. _ Formation OF PALISADE LAYER.— Following the stage when oo a : ged it in irregular tufts, the hymenophore pri re ompact ie ie ees eee of ae 210 BOTANICAL GAZETTE [SEPTEMBER apex, and the two groups of threads grow into each other and inter- mingle to form the common mass of the “volva.”’ In P. squarrosa there is a material difference from the condition just described for C. lagopus, since in this case there are no hyphae on the stem sur- face which grow upward and unite with the downward growing threads. Figs. 2, 3, and 7 show the central strand of hyphae just mentioned; in fig. 5 the character of the blematogen hyphae may be seen. ORGANIZATION OF PILEUS.—Coincident with an early stage in the development of the hymenophore primordium, median longi- tudinal sections show that the fundament of the pileus is becoming differentiated from the surrounding tissue (fig. 8). The hyphae become richer in protoplasm and by interstitial growth form a more compact structure. This organization proceeds from the center outward in a centrifugal manner, the margin of the pileus keeping pace with, and contributing to, the growth of the hymenophore primordium. During the early stages of differentiation of the pileus some of the hyphae arise from the stem, but its later growth _ : is probably due entirely to interstitial and marginal increase of its own elements, which are interwoven in all directions, thus differing from the hyphae of the stem, which in general run parallel to the stem axis. The pileus elements merge gradually with the blemato- gen and there is no sharp line of division between the two struc-_ tures. The cells of the blematogen hyphae, however, are swollen and have thick walls, which stain deeply, while the pileus hyphae are slender and do not take a deep stain after the pileus is well Organized, so that a general distinction is evident. In ens ae ie peripheral threads of the eases ‘composing. = ote i 1917] SAWYER—PHOLIOTA 211 pileus margin at this time is turned downward and often somewhat incurved as a result of epinastic growth, and lies nearly parallel with the surface of the stem, which still slopes outward at a slight angle (fig. 10). FORMATION OF ANNULAR PRELAMELLAR CAVITY.—During dif- ferentiation of the young basidiocarp some ground tissue is left below the hymenophore primordium in the angle formed by the junction of the stem and pileus fundaments. In later development this ground tissue increases to some extent by interstitial growth, but the more rapid growth of the stem, hymenophore, and pileus subjects it to tension, and it very early becomes loose in texture (fig. 4). As the stem elongates and the pileus broadens out, this tension is further increased, so that the ground tissue becomes still looser, with large spaces between the hyphae. At first it only partially tears away from the surface of the hymenophore, and as a result the gill cavity thus formed is weak, with strands of ground tissue traversing it (figs. 13, 14, 16-20). The strength of the pre- cavity varies in different individuals, as has been shown to be the case in Agaricus rodmani (8); but in any case, in later stages, but long before the gills are exposed by rupture of the veil, the strands of ground tissue become completely broken away, __ and the edges of the lamellae are entirely free within the bl ae cavity. ; ORGANIZATION OF PARTIAL VEIL. the terms hleniati or gen’ “universal veil” and “marginal” or “partial veil” have been interpreted by ATKINSON (5), and are used in the same sense here. The formation of the blematogen has already been described. oe radial growth of hyphae in the apex of the young fruit body is very ae ___ Tapid for a time, and a thick layer is formed, enveloping the entire = | Plant, but it is more dense i in the rupee region (Ges ro. ~~ . - become i ps pero ‘Because = corns : — Ast universal veil b mes subject to tet 212 BOTANICAL GAZETTE [SEPTEMBER the ground tissue left in the angle between the stem and hymeno- phore. This tissue increases, both by interstitial growth and by the addition of hyphae which grow down from the pileus margin (fig. 22). By the time that the gills are well formed this tissue occupies a considerable area lying between the margin of the pileus and the surface of the stem, and forming the floor of the gill cavity. It is covered externally by the blematogen, with the inner surface _ of which its hyphae are interlaced, as some of them are with the stem surface. .When expansion of the pileus occurs and the veil is ruptured, it is left upon the stem as an annulate membrane com- posed of two layers, the coarse, scaly blematogen layer below and the partial veil above. ORIGIN AND DEVELOPMENT OF LAMELLAE.—In a recent publica- tion ATKINSON (9) has shown that in the Agaricaceae thus far studied there are two types in regard to the origin and development of the lamellae. First, the ‘‘Agaricus” type, in which the gills arise by downward growing radial salients of the hymenophore, accompanied or preceded by a more or less well developed annular prelamellar cavity. Second, the “(Amanita’’ type, in which there _is no general annular prelamellar cavity, and the origin of the Tasman he Selo eeting Sore thy es ment to the stem, and attached to siege P. sores obviously se es he : belongs tO the first type : that in the course of development of ie jeune bak tas see oy annular, prelamellar cavity, though weak, and a palisade layer are fo eo. ‘The origin and differentiation of the gills from the hymenophore _ e sea a ee 1917] SAW YER—PHOLIOTA 213 an imbedding material obviates the difficulty sometimes met with in the use of paraffin, that delicate structures may be deformed or dislocated by the heat of the oven or in spreading the paraffin ribbons. Furthermore, the cutting of thicker sections, with a sliding stroke, offers little chance for the displacement of structures, which might happen in cutting thin paraffin sections. I mention these points because some might suspect that the tearing away of the ground tissue below the hymenophore, as shown in the following figures, might be due to manipulation of the tissue, but such is not the case. Fig. 16 represents a section near the margin of the pileus; the hyphae of the hymenophore are growing down in little tufts, and at this time present a very loose, uneven surface. A considerable number of hyphae from the ground tissue below may be seen spanning the prelamellar cavity and united indiscriminately with the downward growing tufts of the hymenophore and. with the hyphae in the spaces between them. In fig. 17, from a section a little nearer the stem, Sia. ioe ophore on either side of the sectio presents the same loose, uneven surface as in the preceding figure; but in the middle the hyphae have enlarged at the tips and become blunt, and the ends have ~ grown down to form an even surface, the palisade, from which the — ae _ ground tissue is almost entirely broken away. ‘The reason that the — Palisade is in the middle of ped ete with undifferentiated tissue | on either side, i: dil sections, in pa y hyrecnaphore in t the middle of the s¢ is in the form of a cece ar around the stem | apex, so that ang en oe 214 BOTANICAL GAZETTE [SEPTEMBER is completely free. That this ground tissue has nothing to do with the formation of the palisade is shown by the fact that, as already stated, it is attached indifferently to the hymenophore primordium, and in many cases is largely broken away from the tufts and between them before the palisade layer is formed. Furthermore, these tufts of the hymenophore primordium are not the primordia of the lamellae, since before the origin of the latter they become lost in the even palisade (figs. 17, 18). In those instances where the ground tissue remains adherent to the edges of the lamellae for some time, and not to the palisade between them, it is due to the fact that through the downward growth of the gills the strands of hyphae attached to their edges are subject to less strain than the hyphae attached between them, and so keep their attachment longer. The downward growth of the lamellae may be partly initiated by the pressure in the palisade layer due to the rapid growth and enlargement of its hyphae, which would produce a tendency to throw the palisade into folds.. The chief agency in their formation, however, seems to be the downward growth of radially arranged groups of hyphae in the hymenophore, which are very active in growth at this time, as indicated by their deep stain. These radial lines of deeply staining hyphae push down into the folds of the © _ palisade and form the trama of the gills (figs. rg-21). The further _ growth of the lamellae in depth takes place by apical and interstitial growth in the trama. Later stages in development (fig. 23) show the hyphae from the trama turning outward on all sides to add to ee et Oe lates ret ea | : Pholiota flammans . — OF BASIDIOCARP.—The very young ionlt: bois, = efore any internal differentiation has taken place, is a compact _ structure, composed of slender, intricately interwoven hyphae, ae . ed H in diameter, and rich in protoplasm. The hyphae havea __ general direction of growth away from the substratum n, and many 1917] SAW YER—PHOLIOTA 215 development of the blematogen, which is probably present from the first appearance of the fruit body primordium. DIFFERENTIATION OF STEM FUNDAMENT.—As_ development proceeds, the hyphae in the base of the primordium take on more active growth than the others, and by interstitial increase form a very dense structure. This new area of growth, which is the stem fundament, is shown as a deeply stained region in the base of the fruit body in fig. 25. As growth continues, the cone-shaped stem fundament advances toward the apex of the fruit body. In fig. 26 the most deeply stained portion represents the rapidly growing, progressive apex of the stem fundament; the more compact tissue below represents its earlier differentiated base; and the outer zone of loose tissue surrounding the whole is the blematogen. DIFFERENTIATION OF HYMENOPHORE AND PILEUS PRIMORDIA.— The first evidence of the hymenophore primordium is the appear- ance of a ring of compact, slender hyphae which surrounds the upper part of the stem fundament and grows down into the ground tissue, clothing the latter. The appearance of these differentiated hyphae marks off the pileus area from the stem fundament. In some cases the pileus fundament probably exists before the appear- ance of the hymenophore primordium, as indicated by seg ape : divergence of the hyphae from the apex of the stem fundament or _ by the more rapid growth in the region of the future pileus; “but no sharp distinction can be drawn b 3 OF P _and stipe u rig OFS 4°. rors eee +. atc Pa An early stage in the development of the latter i is shown in fig. 30. _ As development continues, the pileus and hymenophore progress Pedr in growth in a centrifugal manner. New ieneseg from the pileus pease contribute to the hymenophore takes plac ce e in +h 5 Oe oa 216 BOTANICAL GAZETTE [SEPTEMBER it radiates from all parts of the surface as a loose aggregation of hyphae with numerous interhyphal spaces (fig. 29). The new elements arise chiefly in the apex of the young fruit body and extend outward in a radial direction, curving backward as the fundament of the basidiocarp elongates and as the stem and pileus primordia are differentiated. This peculiarity of the blematogen is like that in P. squarrosa. This downward growth continues until a thick cover- ing is joumied (fig. $1). The elements of the blematogen are thick- walled hat larger than the other hyphaeoi the basidiocarp, but they are not caiasins globose, as in P. squarrosa. Early in its formation some of the threads begin to break down and gelatinize, and the universal veil soon becomes a gelatinous matrix, imbedded in which may be recognized the remnants of hyphae not yet disorganized. Such a condition exists in fig. 31, _ and a high magnification (fig. 38) shows a sharp contrast between the gelatinized blematogen and the cortex of the pileus at this stage. : very similar condition of the universal veil has been weaeis in see oiget ambigua by ZELLER (25). | The disorganization of the blematogen siosciente does not go beyond the degree shown in fig. 38. Sections perpendicular to the _ pileus in mature specimens show a very similar condition; there is a gelatinous ground substance filled with dead hyphae whose general course is parallel to the surface of the pileus. —— oe sislonee rose part and the tension. exerted upon it by the ig pileus the blematogen breaks up into scales. These : POR differ very markedly, however, from the stout, pointed ~ scales of P. enemibees’ bad ie thin ¢ and aetente Je » more — a iw FR er wo id ‘ f P. a. squares < J & biidt UL ! e ring n € stem, as indicated i in - 2 - epo’s Sylloge (23), in whic =“) eae plant : : ; 1917] SAW YER—PHOLIOTA 217 formation in the preceding species. The ground tissue is loose from a very early stage, and through expansion of the different parts of the fruit body it becomes torn away from the lower surface of the hymenophore. This separation from the hymenophore is com- pleted at an earlier stage than in P. squarrosa, and consequently a well defined cavity is present before the origin of the lamellae (figs. 34, 37). During the development of the hymenophore primordium and the breaking away of the ground tissue below hyphae are growing down from the pileus margin. These threads penetrate the ground tissue below the prelamellar cavity and mingle with those on the surface of the stem. In fig. 33 they may be seen curving inward from the pileus margin. In the stage represented here they have not yet reached the surface of the stem, and the loose ground tissue surrounding the latter may still be seen between it and the advan- cing hyphae from the pileus margin. These threads are sharply contrasted with the other tissue of the basidiocarp because of their Shs Salon, Which i tee aie nin ead os can ‘ addition, they may be distinguished from the blematogen external to them by their deeper stain. These hyphae from the pileus — , together with the ground tissue below the hymeno- -phore, form the pattinl veil; it tears away from the stem at an early stage in the expansion of the plant, and may in some ee iculate veil. — : Onions AND DEVELOPMENT OF oe ola ad ae i the conditi P. squarrosa. Here we have ._ ridges. If no palisade c e differ 218 BOTANICAL GAZETTE [SEPTEMBER been stated, the hyphae in the palisade layer are not crowded enough to produce any great pressure, and it would seem that the origin of the gill salients, which appear as downward folds of the palisade, is due entirely to the growth and elongation of radial lines of hyphae in the hymenophore, which push the palisade down in folds, the young gills, as described for Hypholoma sublateritium (1) and Siropharia ambigua (25). The gill salients are broader than in P. squarrosa, and this may be due to the fact that when thrown into folds by downward growth of the hyphae above, because of the less crowded condition of the palisade, they are not subjected to as great lateral pressure as in that species. Fig. 39 is from a tangential longitudinal section of a basidiocarp with sterile gills, that is, the palisade layer has failed to form. The _cystidia, which develop from the trama of the gill, are very notice- able as deeply staining clavate bodies. The situation presented here is interesting because of its bearing on the question recently raised by LevINE (21) in regard to the origin of the lamellae in the Agaricaceae. The points of growth for the origin of the lamellae, as described by ArkmNson in several species of the Agaricaceae, including Agaricus rodmani (8) and Coprinus comatus, C. atramen- tarius, and C. micaceus (9), occur in radial areas of hyphae in the hymenophore, which develop centrifugally and grow down more rapidly than the other hyphae. These areas are the gill tramae, and push the palisade into regularly spaced folds, which are the salients of the lamellae themselves. This method here. of origin of the lamellae occurs in the three species described According to Levine’: S$ conception, radiating ridges of palisade = cells arise in the fundamental tissue, and by continued differentia- ee tion and downward growth of new palisade cells, split apart. Bee adjacent halves of en come together and unite to form a lamella. The trama of the gill would ee be formed by _ the coming together of preexisting palisade cells ae! ; ee ee eal) be formed. In this case, however, no 1917] SAWYER—PHOLIOTA 219 Pholiota adiposa PRIMORDIUM OF BASIDIOCARP.—In the youngest fruit body sectioned the mycelial threads grow out from the substratum to form a compact mass of hyphae which are closely interwoven and run in all directions. From this structure hyphae gradually assume -an upward direction of growth, forming a papilla-like projection (fig. 42), the fruit body primordium. The threads in the basal mycelium from which the fruit body arises are very uneven in size; those of the primordium are even in size, with free ends radiating out all over the surface. STEM FUNDAMENT.—The stem fundament probably differen- tiates first in the base of the fruit body, as in the preceding species. In fig. 43 its apex appears as a compact, dark-staining region near the top of the basidiocarp, surrounded by the looser tissue of the young blematogen. The fundament hyphae are very slender at first, dense in protoplasm, and closely . running in all directions. PRIMORDIA OF HYMENOPHORE AND PILEUS.—When the hymen- ophore and pileus primordia appear, the stem has become well organized as a compact conical area, surrounded by the loose a universal veil. The first differentiation of the pileusfundament be- __ comes evident through the growth of hyphae upward from the stem _ apex; these spread outward laterally, so that at this stage the : stem and pileus areas together resemble a sheaf of wheat. At the _ same time some of these hyphae Deceane. subject to strong. epinastic : growth, and curve down in g the primordium of the hymenophore, which definitely | differentiates ‘the pileus area from the a m fundament. The gr pileus continues b a ie si Sa a ag —— broadens age by growth within 3 itself etted oo 2 The baliee of the ijineaopnase delendtien =a gated ‘into. hier (fig. 48), as as in - - still: re | attached — these din tot 220 BOTANICAL GAZETTE [SEPTEMBER species (figs. 45, 47). In later stages it loses this decurrent character. BLEMATOGEN.—The universal veil exists from the beginning; its development proceeds very much as in P. flammans. At first its hyphae radiate from all over the surface of the basidiocarp. Later the growth of new elements is largely confined to the apex. The peripheral cells become enlarged, thick-walled, with a diminu- tion in protoplasmic content (fig. 52). The outer ones appear empty and dead. Gelatinization takes place here, as in P. flam- mans, but later, after the gills are well formed. Sections through the mature pileus show that the blematogen has a structure very comparable in the two species, in either case composed of a struc- tureless matrix in which are imbedded dead hyphae, with a general Hel to the p tface. At first disorganization occurs only ower the pileus, but in the mature plant the gelatinization takes place over the entire surface. The mature pileus in P. fammans is dry, and in P. adiposa is gelatinous or viscid. This difference is due to the fact that in the latter species the disorganization of the blematogen elements pro- ceeds farther than in the former, so that the walls of the hyphae become more gelatinous, with a greater capacity for absorbing — _ water. The surface of the blematogen breaks up into scales, as in P. fammans, but the scales are very different in character. They . : are not thin and fibrillose here, but in wet weather appear like little lumps of jelly on the surface and are easily: lost, so that it is not uncommon to find old fruit with the surface of ae the pileus nearly free from them, especially over the central the: ground tissue below the (sae making it loose, ee spaces between the hyphae. At first, snes sof hyphae span the to the hymenophore , but these have all 1917] SAWYER—PHOLIOTA 221 with some hyphae which grow down from the pileus margin. This growth, however, is not as strong as in P. flammans. The partial veil is covered externally by the blematogen. It ruptures at the pileus margin during expansion of the plant, leaving a thin and fugacious annulus on the stem. _ ORIGIN AND DEVELOPMENT OF LAMELLAE.—The origin and growth of the gills take place in this species much as in P. flammans. The first evidence of the origin of the gill salients is the downward projection of the palisade layer in broad folds (figs. 50, 51). A single one of these broad folds includes several of the tufts which earlier appear in the hymenophore primordium and become lost in the palisade; consequently, these tufts cannot be considered as gill fundaments or directly concerned in their origin. At the apex of the folds the ends of the palisade cells may in some cases spread slightly apart, showing that considerable pressure is exerted by the downward growing hyphae from the hymenophore above. Under no circumstances, however, do the gill salients show any evidence of splitting; the hyphae merely spread slightly apart at the ends, and in later stages come together again to form an uninterrupted palisade. Serial sections show that the formation of the gill salients is radial and centrifugal. ‘Figs. 53, 54, and 55 show a condition that might easily lead to z a ee wrong interpretation of the origin of the lamellae by one not familiar with the orientation of the parts involved. A simi condition existing in Agaricus rodmani has been explained by ATKINSON (8) and so will not be gone into in detail here. Te sections are tangential in the margin of the pileus at a stage in Es development when the pileus margin isenrolled. The attachment — of the gill trama both above and below does not mean that the : __ trama of the gill has grown down and pe as ee = oF a as fie’ appear at “first glance. The pileus margin : 222 BOTANICAL GAZETTE [serremaun Sequence of plant parts The relative time of origin of the primordia of the basidiocarp is of some historical interest. Fries (17), influenced perhaps by the preformation theory, still in vogue in his time, believed that all the parts, pileus, stem, and hymenophore, although indistinguish- able, existed already formed in the young fruit body and unfolded simultaneously. Scumirz (24) held that a successive formation of new parts occurred; that the development of new parts rose upward just as gradually as in the higher plants, so that those stariding higher came into evidence later than those below; and that therefore the matrix developed before the stipe, the latter before the pileus, and the latter before the hymenium. Later, Fayop (15) formulated a general law to the effect that the first part to be differentiated is always the pileus primordium. More recent work has shown that no general rule can be laid down as to what primordium shall have precedence in differentia- tion. In Agaricus campestris (2), A. arvensis (3), A. rodmani (8), Armillaria mellea (4), and Siropharia ambigua (25), the hymeno- phore primordium is differentiated first. In Hypholoma sub- — lateritium (x), H. fasciculare (11), and Amanitopsis vaginata (7) the | . pileus area is first outlined. The formation of the stem fundament is the first differentiation to take place in Lepiota cristata and L. seminuda (10), several species of Cortinarius (14), Rozites gongy- lophora ids ~ the 3 species of Pholote described. : Even in the same species y occur as to the relative : of the different t primordia. ATKINSON (10) has" shown this to be eine § in Agaricus arvensis (3) and Lepiota : time of clypeolaria (6). In P. flammans a would appear that the funda oe ment of the pileus i nen a primordium, and this may be true of the other two ‘species: a ih all 3 species, however, the er of ~ sities o 1917] SAWYER—PHOLIOTA 223 peripheral region, and radiate from the entire surface of the fruit bod : y. 2. The blematogen is present from the first. differentiation of the fruit body primordium, and in its earliest stages consists of the loose, radiating peripheral hyphae. In subsequent growth it forms a thick layer enveloping the entire plant; in’ P. flammans and P. adiposa it becomes partially disorganized by gelatinization. 3. The formation of the stem fundament is the first differentia- tion to take place in the young fruit body. It originates in the basal part of the basidiocarp and by growth and differentiation progresses toward the apex. 4. The primordium of the hymenophore is differentiated around the apex of the stem fundament as an annular internal zone of new growth. Frequently, before the hymenophore appears, a slight ~ divergence of hyphae from the ‘acini apex indicates differentiation of the pileus. When theh dium is differentiated, it marks off clearly the limit between the pileus and stem. It consists of slender hyphae, rich in protoplasm, which grow down- ward. At first the lower surface is uneven and loose, but by con-_ tinued growth the hymenophore becomes compact and the hyphae grow down to the same level, forming an even: palisade area. ae ies of the spose and es aeneee! of the _— — ee 1 I : - S ae 4 4 i * 3 ees os. Th lar . ae of the ground tissue f irom the low f. f tk 1 e, due : to the tension exerted by the growth and expansion of the plant — parts. It is weak in P. SNGITOS, @ as wen Femeet flammans — oa and P. adiposa, bef As 224 BOTANICAL GAZETTE [SEPTEMBER in these downward growing areas in the hymenophore, and the first folds in the palisade are the salients of the lamellae themselves. In P. flammans and P. adiposa the gill salients are very broad; in all 3 species their origin and differentiation is centrifugal and their subsequent growth is downward into the gill cavity. In conclusion, I wish to acknowledge my deep obligation to Professor G. F. ATKINSON, under whose direction this work was done, for his unfailing interest and many helpful suggestions. CoRNELL UNIVERSITY Trmaca, N.Y. LITERATURE CITED 1. ALLEN, CAROLINE L., The development of some species of Hypholoma. Ann. Mycol. 4:387-304. pls. 5-7. 1906. 2. Atkinson, Gro. F., The deosaunect of Agaricus campestris. Bort. GAZ. 42:241-264. pls. 7-12. 1906. + -, The development of Agaricus arvensis and A. comtulus. Amer. Jour. Bot. 1:3-22. pls. 2. 1914. The development of Armillaria mellea. Mycol. Centralbl. 4: _ 112-121. pls. 2. 1914. » Homology of the universal veil in Agaricus. Mycol. Centralbl. St13-10. p Bs. 13. 1914. ; 6. pls. 13-16. 1914. es denice! of Amanitopsis — Ann. Mycol. 12: 369-392. ve 17-19. 1914. 8. ————, Morphology and development at dissin rodmani. Proc. donk s Phil. Soc. 54: 309-343.' pls. 7-13. 1915. 5 9- , Origin and development o yy ee acter Bor. Gaz. &: soi oe as: Back cae t Lepiots 7 vb pee, Ann. Mycol. ie dla bs is = NY. Bot. Gard. 6: 1916. ir. Beer,R oa one Joe Agari ae : Ann. Botany 2§:683-689. m 52. 19rr. oe Ce ee _-myceten + i. TT. 98-108. de a 1877. oe 1917] SAWYER—PHOLIOTA 225 15. Fayop, V., Prodrome d’une histoire naturelle des Agaricinées. Ann. Sci. Nat. Bot. VII. 9:181-411. pls. 6,7. 1880. 16, FiscHer, C. C. E., On the development of the fructification of Armillaria mucida Schrad. Ae Botany 23:503-507. pl. 35. 1909. 17. Fries, E., Systema orbis vegetabilis. 1: 1825. 18. Hartic, R. , Wichtige Krankheiten der Waldbaiime. 12-42. pis. 1, 2. 1874. 19. HorrMann, H., Die Pollinarien und Spermatien von Agaricus. Bot. Zeit. 14:137-148, 153-163. i 5 1856. 20. ———,, Beitrage zur t d Anatomie der Agaricinen Bot. Zeit. 18: 380-305, 397, 404. pls. 13, 14. 1860. 21. LEVINE, M., The origin and development of the lamellae in Coprinus micaceus. hat. Jour. Bot. 1:343-356. pls. 39, 49. 1914- 22. MOLterR, A., Die Pilzgirten einiger siidamerikanischer Ameisen. Bot. Mittheil. Teen, 6:1-127. pls. 1-7. 1893. 23. Saccarpo, P. A., Sylloge Fungorum. 5:153. 1887. 24. SCHMITZ, J., Mycologische Beobachtungen als Beitrige zur Lebens- und Entwicklungsgeschichte einiger Schwimme aus der Klasse der Gastro- -myceten und i Linnaea 16:141-215. pls. 6, 7. 1842. 25. ZELLER, S. M., Development of Sieubberie ambigua. Mycologia 6:139- 145. pls. 124, 125. 1914. EXPLANATION OF PLATES XVI-XX The following microphotographs were made with the Bausch aad Lomb . Ce ne Den eee ee ee ee . of figure; oa leeplh essa oe of cugoneble rating from summit; Laue 226 BOTANICAL GAZETTE [SEPTEMBER portion of blematogen; at extreme right may be seen a part of hymenophore primordium with loose ground tissue below; 56. Fic. 6.—Left side of median section about the time when hymenophore primordium is first differentiated; tangled, compact mass of hyphae of very young hymenophore near center, with looser ground tissue surrounding it; 133. Fic. 7 powan savant at about _ same ase of differentiation as fig. 4; two compact, ; from summit blemato- gen hyphae are curving cobnad and downward: Phen 8.. Raucoug ee comical stem flea ieee hymenophore pri ither cid as a more Rae central area; loose ground tissue clothes stem, ‘and outside is deep-stained blematogen; 18. Fic. 9.—Tangential section of same fruit body; hymenophore primordium appears as dark horizontal area, with uneven lower surface; i r dar region just below is oblique section of stem surface; 18 Fic. 10.—Median section, sim ithge whit palisade het formed gill avy Mbprars Ae & hence a almost closed because of epinastic growth of -pileus ; below, the looser ground tissue; 133. Fic. 11. a Veupeitial section of same fruit body; ground tissue is tearing away from hymenophore to form gill cavity; above hymenophore is crescent- shaped pileus, with the much thicker blematogen outside; X33- _ fis. 12 -Higher mga ape of section near preceding to show blunt low; above is dense hymen- EE rag Fic. 13.—Blematogen has broken into scales; stem and pileus are well organized; b , ae | r ee of ground tissue traversing it; dark line between pileus and hymenophore : indicates area of more rapid growth; X13. aS . piace seis nce pe caige ecotssi et 13, and showing same features enlarged; X32. _ a bt I i ~~ Pangential section, showing compact iyeuigins él no be - nt hae not t oi ay +O oo become even in ey o A. gr ee pe tare -Serial tang, eae tive nee : hs 16 fynopore uneven an levity is weak _ ground tissue still attached to fips “id 1917] SAW YER—PHOLIOTA 227 Fic. 22.—Left side of median section in a stage waar mane are a differentiated; at extreme left are hyph into ground tissue below; knife has sé passed lengthwise through a : gl, ies it thin enough to look through and see level palisade between it and next gill; Fic. 23.—Tangential secti howing gills with t 1 palisade; 148. PLATES XVIII, XIX Pholiota flammans Fig. 24.—Median section of very young fruit body, which is broken just above peacatwe of rotten wood; loose, radiating threads represent early stage in formation of blematogen; no internal differentiation has taken place; X60. Fic. 25.—Stem fundament forming in base of fruit body, its = ae stained very deeply; outside is blematogen; 36. Fic. 26.—Slightly later a in hicks by a growth, cere of stem _ fundament has advanced to summit of fruit body; X36 les 27. —Somewhat — fruit sania with stem faunal differentiated, rker area; very deeply stained, ee are scattered through stem fundament; 36. Fic. 28. Sane as fig. 27; X36. Fra. 290 7 “18 eee Fie. 209. St Stem area well organized, but ho other differentiation X36. fines 3o.—Small area on either side with looser ground tissue below repre- = 31-—Stem and pileus areas well organized; } menophore st WS 228 BOTANICAL GAZETTE [SEPTEMBER Fic. 35.—Tangential section, showing early stage in organization of palisade by hymenophore; gill cavity below; 125. Fic. 36.—Tangential section very near stem, showing two broad gill salients, covered by palisade; some clavate cells of latter project beyond surface, giving rough appearance; note disorganized condition of universal veil; X86. Fic. 37.—Tangential section, showing even palisade and large gill cavity; 31. Fic. 38.—Section highly magnified to show contrast between pileus and gelatinized blematogen; 142 Fic. 39.—Tangential ston of fruit body with sterile gills; note absence of any palisade, and the cystidia, which develop from trama tissue of gill; 144. Fic. 40.—Tangential section, showing normal gills at about same stage as preceding; hyphae of trama may be seen turning outward to contribute to palisade; cystidia are visible on edges of lamellae; 142 Fic. 41.—Tracheid of Picea inclosed in tissue of tps: this fruit body was in advanced stage of development, with lamellae well differentiated; 230. PLATE XX Pholiota adiposa ‘Fic. 1G. 42.—Median section of very young fruit body; am ki aS Sp ahmlinalinscaonmeRenaaEE threads radiating from surface 8 t 1 summit of fruit body; ™43- oe og 45- . ee ix ow SDP ORAS Se stem and pileus are well organized . and hymenophore is forming palisade; heavy blematogen shows no signs of a disorganization that occurs later; X18. oe Fro, 46.—Tang a same stage in development; because 8 BOTANICAL GAZETTE, LXIV PLATE XVI SAWYER on PHOLIOTA PLATE XVII AWYER on PHOLIOTA BOTANICAL GAZETTE, LXIV PLATE XVIII SAWYER on PHOLIOTA BOTANICAL GAZETTE, LXIV FEATE XIX SAWYER on PHOLIOTA PLATE XX BOTANICAL GAZETTE, LXIV << Lae © ms | ) = ew c a ats 4 SAWY 1917] SAW YER—PHOLIOTA 229 _ Fic. 50.—Same, nearer stem; note the 3 slight downward projections of palisade, which are very young gill salients; some ground tissue still clings to them because their downward growth relieves tension upon it to some extent; X67. Fic. 51.—Section from same fruit body near stem, showing very broad gill salients; 250 Fic. 52.—Large, thick-walled cells of blematogen; 250. Fics. 53-55.—Sections tangential in enrolled pileus margin; fig. 53 (X33) has not cut into gill cavity; ‘‘backs” of gills show as deeper stained areas; in fig. 54 (X154) gill cavity is reached and gill is shown in middle with trama in center and palisade on either side; its origin is in hymenophore both above and below; fig. 55 (56) is nearer stem. Fic. 56.—Tangential section, showing well-formed gill, with trama and palisade; X154. METHODS OF STUDYING PERMEABILITY OF PROTOPLASM TO SALTS S.C. BRooKs Investigation of the permeability of protoplasm to electrolytes has led to many apparent conflicts between evidence secured by different methods and between the theoretical conclusions based thereon. An intensive study of the evidence, and of the methods themselves, has shown that these apparent conflicts are in large _ measure due to an imperfect understanding of the limitations of the methods or to unwarranted assumptions as to the nature and reactions of living matter. It is therefore of interest to consider critically the methods heretofore employed in the study of perme- _ ability in order to determine which of these methods may be con- sidered most reliable, and thus to acquire a broader understanding — __ of the problem, and to lay the foundation for further investigation. a _ The methods employed i in the investigation of the permeability 8 tes fall into 4 general categories, in which a we criteria employed are: (1) chemical pase igh of tissue extracts or of solutions bathing the tissues, (2) visible « es within the = - (3) turgidity of cells or tissues, and (4) decesisl ‘conducts S f tissues or of masses of cells. To these ‘may = added a diffusion oS s ca __ ANALYSIS OF TIssu Chance mt by Js (0). " Filaments of a “species <3 1917] BROOKS—PERMEABILITY 231 then tested, gave no reaction. This method, although positive, can yield only qualitative data. As a method for the investigation of protoplasmic permeability, quantitative analysis of tissue extracts involves several important sources of error, among which may be mentioned the presence of salts in the intercellular spaces and in the cell walls, where they may be held in solution or by adsorption, variations of the con- centration and constitution of expressed juices dependent on the pressure used in extraction (cf. MamELI 30), and, most serious of all, adsorption or chemical union of the salts within ‘the cell. Thus, while aluminium ions might displace potassium ions in an adsorp- tion compound, sodium ions might displace the Sapien ions to a small extent only. In this way the free aluminium content of the cell would remain low, and the original rate a endosmosis of aluminium salts would be maintained, while that of sodium salts would steadily deorease as the free sodium-content of the cell increased. A similar effect might be produced by the formation of hydrates of aluminium and sodium; the former being insoluble would form a precipitate, while the latter would sain in solution." - The relative permeability of the t would then be made to appear other than it actualy wie The last error also | affects methods involving the amount of salt taken by tissues from by experiments of this type, such | - PP. 453 ff.), PANTANELLI (51), DE Rurz: DE ‘LavIson el 56), Count and DE Rurz DE Lavison (4, 5), M (EURER (36), and many others. : PAINE (50), usi , drew the conclusion that yeast \a™s : = Doce aie 7 . ie cells are wholly i able to i Jif i ~ Its.2 eeeg! a x ae absorption of oe salts nates the yeast cells, b n pagilaieag cmaeyners 232 BOTANICAL GAZETTE [SEPTEMBER ANALYSIS OF SOLUTIONS BATHING THE TISSUES.—The method | of analysis may also be applied to the diffusion from living cells (“‘exosmosis’’) of substances normally present in the cells and retained by the impermeability of the protoplasm (they may accumulate in the cell walls of terrestrial plants in quantities sufficient to maintain a condition of equilibrium with the solution inside the cell, and may diffuse out when the cells are placed in water). Under certain conditions these substances may be made to diffuse from the cells in appreciable quantities. The experiments — of WACHTER (69) on the exosmosis of sugar from onion bulb scales seemed to indicate that this exosmosis was inhibited by various salts. In the light of more recent evidence it seems possible that this was due to antagonization of traces of toxic salts in the ‘“‘Leit- ungs-Wasser”’ which he used. Other experiments have dealt with the absorption of salts from a : the solution as well as with exosmosis. The results of the experi- oe ments of TRUE (63), TRUE and BARTLETT (64, 65, 66), and MERRILL. — (34, 35), like those of WAcuTER, were visible only after several - hours, and the intervening effects upon permeability could not be determined. There was also opportunity for Baa ckmmehs pro- . cesses” and other complications to influence the tion of salts to a marked extent during this interval, and a probability that Le _ some of the external cells would be killed and would give off their A contained solut lution. _Ttis quite prot bl : that these effects are of importance in exper Ss duration as those of the investigators mentioned. The most serious objection to using the analysis of the i im ents of such | Ca of permeability i is that the ‘method does not disting lish - between | difasng ov), it it will continue to diffuse i in, while a roubxtance which -— Kations v was agree only to their physi expected of periments of lo 1917] BROOKS—PERMEABILITY 233 increased exosmosis may be due, not to increased permeability, but to increased production —_ the cell of the substance which diffuses out. Visible changes within the cell This method, although sometimes valuable in the Servedtiontion of the penetration of substances like the alkaloids which form intra- vitam precipitates, and acids and alkalies which cause color changes of pigments or intra-vitam stains, has found little application in the study of the penetration of inorganic salts. OsTERHOUT (39) showed that crystals of calcium oxalate form in the root hairs of seedlings of Dianthus barbatus (previously grown in distilled water) within a few hours after their immersion in dilute solutions of calcium salts, and the subsequent normal growth of the cells proved that they were not injured. ENDLER (7) followed microscopically the entrance of intra-vitam stains (neutral red and methylene blue) into various plant cells under the influence of various kations. He also investigated the rate of disappearance of the dyes from stained cells, living and dead. The experiments are extremely instructive, showing that at 24 OF more hours the Passage of dyes through the membrane was increased by kations- ie in mie hate orters Na Dig E is | ror7] BROOKS—PERMEABILITY : 237 carried far enough to cause plasmolysis, we have a means of avoid- ing this objection. We may consider first those methods in which plasmolysis occurs. METHODS INVOLVING PLASMOLYSIS 1. Concentration Required to Produce Plasmolysis——DE VRIES (67) noticed that the concentration of a glycerine solution just concentrated enough to produce plasmolysis was higher than that expected from the calculated osmotic pressure of the solution. He attributed this to the penetration of glycerine into the cell. On the assumption that an increase in the concentration of a given substance required to produce plasmolysis indicates an increase of permeability, LEPESCHKIN (23, 24, 25, 26) and TRONDLE (62) claim to have demonstrated an increase of the permeability of the protoplasm due to increased illumination; and EcKERSON (6) seeks the cause of the thermotropic curvatures of roots in an increase in permeability due to rise in temperature. By the same method KREHAN (20, 21) has studied the effect of potassium ‘cyanide on the permeability of cells of Tradescanta discolor, the _ experiments seeming to indicate that dilute sol 3 (0.001 M) of potassium —, cause a temporar y and eve ible increase in permeability, and hat t this is f jeg d rea: in p ea! if - which begins si 4, ly ee eo be esibility. oe "Oiseiaoee Cy aa t solutions of L cal os chlorides, either of which alone is unable to prade ! (of cells of Gites Se sp.), may cause rapid plasmolysis when mixed in such proportions that the ratio of sodium atoms to those cof se cal chum is about 2 20 tot 1 $inc } 238 BOTANICAL GAZETTE [SEPTEMBER This alteration he supposes to be the production of complete permeability. Sztics (61) has since stated that the alteration consists of a hardening of the protoplasm, since centrifuging no longer displaces the cell contents. He also found the “hardening” to be temporary, and to be followed by “‘reliquefaction.” LEPESCHKIN (27) claims to determine with great accuracy, by a method based upon the difference in the osmotic pressures of isotonic plasmolyzing substances, the absolute rate of penetration of these substances. It is impossible to explain the method clearly and at the same time briefly, but its essential features are as follows: a comparison of the osmotic pressure of a saccharose solution which will just cause visible plasmolysis, with that of a glycerine solution which, following the saccharose, will cause no change in volume (as determined by LEPESCHKIN’s criterion) shows — _ the latter to be the higher. If we let u represent a factor propor- tional to the permeability of the protoplasm to the glycerine, and assume that the protoplasm is impermeable to saccharose, then | =e, » where C” is the concentration of glycerine found to be isotonic with the saccharose solution, and C the concentration calculated to be isosmotic with the saccharose solution. For saccharose we may substitute any substance to which the proto- plasm is supposed to be impermeable, and for glycerine any inkl 2 stance whose rate of penetration it is desired to measure. This method would be exact provided the following assumptions — were in accord with the facts: oe the prtogsm 5 is impermeable to the control substance (in this case ; (2) neither of the substances used causes any alteration i in the permeability of the protoplasm; (3) no exosmosis occurs. All these assumptions are _ rendered highly improbable by the evidence already secured by _ other methods, and additional evidence against their validity will . - . be submitted by the writer in a subsequent paper. LEPESCHKIN also appears to assume that there is an effect on ss me ie water equilibrium caused by the simultaneous age ee - eee et he aed dependent 1917] BROOKS—PERMEABIL ITY 239 basis. The method of LreprscHKIn is therefore of extremely doubtful value. 2. Recovery from Plasmolysis.—Recovery of plasmolyzed cells was first noted by Kies (17) in 1887, who found that glycerine was able to penetrate the plant cell. He was unable to detect recovery of.cells plasmolyzed by solutions of potassium nitrate or sodium chloride. Dr Vries (68) obtained similar results at about the same time. JANSE (16), whose work has been quite generally overlooked, demonstrated the penetration of potassium nitrate, sodium chloride, and saccharose by observations on the recovery of plasmolyzed cells of the marine algae Chaetomorpha aerea and Dictyota sp., and Spirogyra nitida, Tradescantia discolor, and Curcuma sp. It was thus conclusively shown that at least some inorganic salts can penetrate living cells of many types of plants. OVERTON (48) was unable to observe any cases of recovery of cells plasmolyzed by inorganic salts. He supposed this to be due _ to the insolubility of such salts in lipoid substances, which he supposed to constitute the plasma membrane. It has been pointed out by OstEeRHOuT (41) that OvERTON in all probability over- — looked the recovery of the cells which he used, confusing the sub- sequent “false plasmolysis,” due to the injury of the cells, for a continuation of the true plasmolysis. OstERHOUT showed thata _ great variety of salts penetrate and cause recovery. OsTERHOUT _ also showed that the rate of recovery of Spirogyra cells was more rapid when a salt of one of certain monovalent kations was used to produce plasmolysis than when a calcium salt was similarly used.* It was impossible to establish more than the most general quantitative relations in these experiments. Recently Frrrmnc (8) has conducted an extensive series of investigations on the per- meability of cells of Tradescantia discolor L’Heritier (Rhoeo discolor _ Hance). His data may be most easily understood if stated graph- : ao ically. lates 8 strips of — were ae aks = 240 BOTANICAL GAZETTE [SEPTEMBER abscissae concentration of the plasmolyzing solution would be a straight line. It was found, however, that such a curve was concave to the axis of the ordinates. This indicated a decrease in the rate of recovery with time. Firrinc considers this to establish the fact that such salts cause a progressive decrease in the per- meability of the protoplasm. He considers the possibility that exosmosis might have occurred in his experiments, and cites experiments which supposedly show that all possible exosmosis had taken place during the preliminary 4-6 hours’ exposure of the tissues to distilled water. There are serious discrepancies in his data, such as the fact that a solution of a higher osmotic pressure is required to produce plasmolysis in tissues from which all possible exosmosis is supposed to have taken place than is required to produce it in otherwise comparable tissues from which no exosmosis occurred. It is probable that Firrmnc has some important variables in the method which he has employed, and since he has failed to investigate the effect of salts of monovalent kations on exosmosis, it is probable that the supposed decrease of endosmosis is in reality an increase of exosmosis, which would have the same effect on the rate of recovery. Firtinc also states that the cells _are wholly impermeable to salts of bivalent and trivalent kations, with the possible cP preiuea of strontium. This i is in conflict with ai. = i i METHODS NOT aoe PLASMOLYSIS In rapidly elongating plant tissues there is usually a very con- siderable pressure exerted by the protoplasts against the cell walls which confine them. If all the cell walls of the stem are thin and elastic, ay) whole stem will be kept i in a stretched condition by’ this 2 a 4 ae cells, ; such as fib ova: 01 la: oe - - . or opal cells, which do not yield to internal pressures ieee eS tissue. If we cut such a stem or aateneln aa € : 1917] BROOKS—PERMEABILITY 241 solution will withdraw water from the cells, and consequently reduce the turgidity and the degree of curvature, while a hypotonic solution will have the opposite effect. The penetration of the protoplasm by a salt with whose solution such a tissue had come into osmotic equilibrium would lead to an increase in the turgidity, and hence in the curvature of the tissue. Dr Vries (67), in the investigation of the isotonic coefficients of various substances by this method, .observed such a secondary increase in curvature. Such tissue curvatures have not since been used in quantitative researches on the permeability of the protoplasm. The writer, however, has found it possible to make use of this method for quantitative determinations of permeability (BRooks 1a). Changes in the volume or weight of animal cells or tissues have been used by many investigators to determine the rate of penetra- tion of electrolytes. Red blood corpuscles and striated muscle have been the most frequently used materials.s As an example of the former, the work of Kozawa (19) may be quoted. This investigator added to 1 cc. of corpuscles centrifuged from defibri- nated blood of various mammals 2 cc. of various solutions of equal osmotic pressure (as judged by the freezing point depression). corpuscles were again centrifuged after a time varying from 15 minutes to 23 hours, and the volume of the mass of corpuscles t noted.® Increase of volume was c oe of the solute. Sodium salts were not observed ne “cause. any = increase in volume. nutes (8) made similar observations. oe In some animals gl penetrate; in others it t did ae ‘not. It was found to be Sebi to influence the ermeability ne to glucose by various agents, cone certain inorganic salts. These conclusions agree with t ; is corpuscles by su unable to influence oa gee y - siden 242 BOTANICAL GAZETTE [SEPTEMBER various hydrogen ion concentrations, or in solutions contain- ing Ca, Mg, Mn, oxalate, or SO, ions (cf. also MasING 31 and LOEB 28). OvERTON (49) made successive determinations of the weight of sartorius muscles of the frog during treatment with various solutions. He reports that no increase in weight took place in a 0.7 per cent sodium chloride solution during a period of many hours; that isotonic solutions of the phosphate, tartrate, sulphate, ethyl sulphate, and acetate of potassium induced no change in weight during 50 hours. After a few hours an increase of weight occurred in solutions of potassium chloride, iodide, bromide, and nitrate, but OvERTON found these changes to be irreversible, and concludes that the normal muscle is impermeable to neutral salts. STEBECK (57), on the other hand, finds that under proper conditions the increase in weight of kidney tissue in a pure isotonic solution of potassium chloride is reversible, and therefore considers that these cells are normally permeable to potassium chloride. In general the permeability of animal cells to neutral salts seems to be less, and - more often characterized by selective peculiarities than that of plant cells. The red-blood corpuscles, for example, may well be considered to be surrounded by a considerably specialized proto- plasmic envelope. The experiments of Lor (29) on the permeability of fertilized _Fundulus eggs to electrolytes are concerned with a peculiarly specialized envelope surrounding the embryo. This envelope is” characterized by an exceedingly small permeability to salts. Thus — an embryo 4-14 days old within the egg membrane survives 3 days of exposure to a solution (so cc. 3 M NaCl+x cc. 10/8 M CaCl.) which is almost instantly fatal to the newly hatched fish. As has previously been noted, generalizations as to the permeability of _ protoplasm cannot be made from data furnished by experiments — on such a membrane, and a more extended discussion of the results , of these experiments would not be profitable pete : - Electrical I conductivity « of tissues or of masses 5 of cals 1917] BROOKS—PERM EABILITY 243 some substance. These charged atoms, known as ions, are not created by the electrical conditions imposed, but already exist in all solutions capable of conducting a current. The rate at which © the current will be conducted by the ions of a given salt will depend upon two factors, the potential gradient and the frictional or other resistance to the migration of the ions. If the potential gradient be kept constant, we may follow fluctuations in the last factor by a measurement of the current, or by a direct measurement of the electrical resistance. If, therefore, we force the current to pass through living protoplasm in a solution, the resistance offered by the protoplasm to the passage of the ions will measure its permeability to the ions in question (the permeability may be regarded as vary- . ing inversely as the resistance). By the use of alternating currents of rather high frequency we avoid large effects due to accumulation of ions at surfaces impermeable to them.” A method of this type was independently employed at about the same time by R6rH (54), BuGARsKY and TANGt (2), and STEWART (58), who found that the conductivity of blood serum was greater than that of blood itself, and that the resistance rose rapidly with increase of the proportion of corpuscles to serum. The blood corpuscles seemed to be slightly or not at all permeable to the electrolytes of blood. The conductivity of the suspension of corpuscles was shown to be increased by haemolytic agents, the corpuscles then being permeable to salts (cf. WOELFEL 70, also STEWART 58, 59). McCieNpon has also attempted to study the changes in permeability of sea urchin eggs during fertilization (32) _ and of muscles in tetanus (33). The evidence from his —— ments on sea urchin eggs agrees with that of Harvey (12), previ- ously mentioned, but difficulties in technique which McCLEeNnpon — | found it impossible to avoid make the data of these experimer exceedingly unreliable. be experiments of OstERHOUT (42-47) 0 on the conductivity a : : : . tissue of ene alga I Lami: tinct . 244 BOTANICAL GAZETTE [SEPTEMBER tion of the solution. The kations are of particular importance. All monovalent kations (excepting the hydrogen ion) produce only ‘an increase in permeability of the protoplasm. This increase, reversible in its first stages, finally leads to death and complete permeability. Bivalent and trivalent kations and the hydrogen ion cause a temporary and reversible decrease of permeability which is followed or superseded by an increase which is irreversible and leads to death of the cells. In a balanced solution such as sea water the resistance remains constant provided the laboratory conditions are such as to maintain the full vitality of the tissue. We have here a method of determining quantitatively the permeability of the protoplasm at any instant, and the data secured demonstrate the extreme importance of progressive changes in the permeability of protoplasm. It would be possible to imagine that the passage of an electrical current through the tissues was responsible, at least in- ‘some measure, for the observed changes in permeability. It would be of advantage, therefore, to check the results of OSTERHOUT’S method by the use of some method entirely free from this possible objection. The method is also applicable to certain types of tis-_ ever the actua sue only, and it is desirable to extend to other types of plants the principles derived by the application of this method. The plasmolytic experiments of OsteRHouT (40) may be explained in the light of the experiments by the conductivity method _ in the following manner. During the time required to produce plasmolysis the permeability has considerably increased in the . . sodium chloride solution and somewhat decreased in the calcium . _ chloride solution. In that time much more sodium chloride has Le : penetisied the cell, therefore, than of the salts of the mixed solution in which the permeability remains normal, and these again more — ? S : than the calcium chloride, and the osmo: ic gradients -s have changed accordingly. The osmotic pressures of the solutions which wil - produce visible gens will then have suffered an increase . ly i osmotic: solutions, and i in this order: calcium “he — very. little, ¢ the mix ion slightly more. and d sodium oe 1917] BROOKS—PERMEABILITY 245 solution, the resulting osmotic pressure will be considerably above that of a similar mixed solution (that is, one just insufficient to cause plasmolysis), and plasmolysis will result. Summary From a consideration of the methods heretofore used in the study of permeability it would appear that the steps most essential to further progress toward the solution of the problem are: (1) a ‘thorough analysis of the various disturbing factors in the methods involving chemical determinations and the satisfactory interpreta- tion of the results secured by such methods; (2) the same type of analysis of the methods depending on turgor, with special reference to the Reon effect of emanate and (3) the establishment of methods of d in ee without — the various disadvantages of the other methods. The writer hopes to show in subsequent papers that the dif- fusion method, which he has devised, answers these requirements, and that it is also possible to interpret satisfactorily the data obtained by certain methods dependent upon the use of turgorasa criterion. e oe LABORATORY OF PLANT PHYSIOLOGY VARD Universrry eed jad pecan ‘Gai. Jour. Micr. Sti. sacs 1883. ee a renee S. pica A study of permeability by the method of ‘tissue ten- sion. Amer. Jour. Bot. 10: 562. T916. a ee a 246 BOTANICAL GAZETTE [SEPTEMBER 7. ENDLER, JosEPH, Uber den Durchtritt von Salzen durch das Protoplasma. I. Uber die Beeinflussung der scope Teta in die lebende Zelle durch Salze. Biochem. Zeitschr. 42:440. 8. Frrrmnc, H., Untersuchungen iiber die Aciniiee von Salzen in die lebende Ze Jahrb. Wiss. Bot. 56:1. 1915. 9- Pui, M., Der Einfluss von Aluminiumsalzen auf das Protoplasma. Flora 99:81. 1908. to. Gydrey, P., Beitrage zur Permeabilitat der Blutkérperchen fiir Trauben- zucker. OR Zeitschr. 57:441. 1913. 11. Hampurcer, H. J., Uber den Einfluss von Salzlésungen auf das vo ee aes: Arch. Anat. und Physiol. 317. 1898. 2. Harvey, E. N., Studies on the permeability of cells. Jour. Exp. Zool. 10:507. IQII. 13- Hecut, Kart, Studien iiber den Vorgang der Plasmolyse. Beitr. Biol. 112137. 1912. 14. eae, S. G., Der Hamatokrit, ein neuer Apparat zur Untersuchung des Blutes. Skand. Arch. Physiol. 2:134. 1891. 15. Henri, V., and Latou, S., Regulation osmotique des liquides internes chez _ les Echinodermes. Compt. Rend. 137:721. 1903. 16. JANSE, J. M., Die Permeabilitat des Protoplasmas. Versl. Med. Kon. _ Akad van Wetensch. Amsterdam, Afdeel. Natuurkunde. III. 4°332- 1887. 17. Kress, G., Beitrige zur Physiologie der Pflanzenzelle. Ber. Deutsch. Bot. Gesells. 5:181. 1887. [. 18. Kozpre, H., Uber den Quellungsgrad der rothen Blutscheiben durch jeculare zlésungen und iiber den osmotischen Druck des Blut- Arch. hak. und Physiol. 154. 1895. oo 19. Ross, S. , Beitrage zum arteigenen Verhalten der roten Blutkérperchen. — III. Artdifferenzen in der Durchlassigkeit der roten Blutkérperchen. Biochem. Zeitschr. 60: 231. 64: 20. KREHAN, ae Ober die Wirkung des Kaliumcyanid auf die Permeabilitat der P Lotos 62:752. 1914. Se , Beitrage zur Physiologie der Stoffaufnahme in die lebende Pflan- 1917] BROOKS—PERMEABILITY 247 26. LEPESCHKIN, W. W., Zur Kenntniss des Mechanismus der photonasti- schen Variationsbewegungen, und der Einwirkung des Beleuchtungs- wechsels auf die Plasmamembran. Beih. Bot. Centralbl. 241:308. 1909. 27. ———, Uber die Permeabilititsbestimmung der Plasmamembran fiir geldste Stoffe. Ber. Deutsch. Bot. Gesells. 27:129. 1909. 28. Loes, A., Beziehungen zwischen —— der Erythrocyten und G hoes, Biochem. Zeitschr. 49: 413. 29. Logs, J., The mechanism of Hates sac action. Proc. Nat. Acad. Sci. 1:473. 1915. 30. MAmett, Eva, Sulla conducibilita elettrica dei succhi e dei tessuti vegetali. Atti Ist. Bot. Univ. Pavia II. 12: 285. 1908. 1. Masine, E., Sind die roten Blutkérper durchgingig fiir P ERennes £ Pfliiger’s echiv, 149:227. 1912. 32. McCLenpon, J. F., On the dynamics of cell division. II. Changes in permeability of devslopiig eggs to electrolytes. Amer. Jour. Physiol. 272240. IQIO. , The increased permeability of striated muscle to ions during contraction, Amer. Jour. Physiol. 29:302. 1912. 34- MERRILL, M. C., Some relations of plants to distilled water and certain dilute toxic soci. Ann. Mo. Bot. Gard. 2:459. 1915. 33- 35- ———,, Electrolytic determination of exosmosis from the roots of plants subjected to the action of various ares tees Ann. pen aah eas IQIS. om R., (4g) eee <- Al 1. et. 3h and C. Cramer. Heit I. erg 38. NATHANSOHN, A., Der Stoffwechsel uel oe oe 39. Osrernovt, W. RY, ‘on the penetration of inorganic sls into ving ae Petopinny. Zeitschr. Phys. Chem. 702408 tae le and ie, : tions. ‘Science N.S. 34:187. rorr. a oe 41. ———,, The permeability of pts tog and he hry io Pe oe nism. Rilo Saber: og See Ae oe “ — 1012. ae See 248 BOTANICAL GAZETTE [SEPTEMBER 46. OstERHOUT, W. J. V., On the decrease in permeability due to certain bivalent kations. ee GAZ. 59:317- IQI5. , The effect of some trivalent and tetravalent ions on pexmeshility. Bot. Gan 59:464. I9QIS. ' 48. Overton, E., Uber die allgemeinen osmotischen Eigenschaften der Zelle, ihre vermutlichen Ursachen, und ihre Bedeutung fiir die Physiologie. Vierteljahrschr. Naturforsch. Ges. Ziirich 44:88. 1 47- eitrige zur allgemeinen Muskel- und Nerveophysiologie Iil. Stillen iiber die Wirkung der Alkali- und coeur auf Skelett- muskeln und Nerven. Pfliiger’s Archiv. 105:176. 1 50. Paine, SIDNEY G., The permeability of the yeast 4 Proc. Roy. Soc. London B. 84:289. 1911. 51. PANTANELLI, E., Uber Ionenaufnahme. Jahrb. Wiss. Bot. 56:689. 1915- 52. PRINGSHEIM, N, Untersuchungen iiber die Bau und die Bildung der 49- Pflanzenzel 53- QUINTON, R., Permeabilité de la Sieti extérieure de l’invertébré marin, non seule incat a l'eau, mais encore aux sels. Compt. Rend. — 952. 54. Rérx, W., Elektrische Leitfahigkeit thierischer Flussigkeite: 55- De Rurz DE Lavison, J., Du mode de pénétration de eas sels dans la plante vivante. Rev. Gén. Bot. 22:225. 1910. _—————, Essai sur une théorie de la nutrition minérale des plantes vascu- laires. Rev. Gén. Bot. 23:177. 1gIt. 57- SIEBECK, R., Versuche iiber die diosmotischen Eigenschaften von Zellen. Miinchener. Med. Wochenschr. 59:1126. 1912. 58. Stewart, G. N., Elektrischer Leitfahigkeit thierischer Flussigkeiten. Zentralbl. ; Pioicl: 15:332. 1897. : 59- ————, The behavior of the haemoglobin and electrolytes of the colored tions of decticlites to cells. Jour. SES and Exp. Ther. 1:49- 1909-10. 61. Sziics, yt ini kteristische Wi des Al das Protoplasma. J Jahrb. Wiss. Bot. 52: 269. 1 62. TRénDLE, A., Der Einfluss des Lichtes auf die ane re der Plas- mahaut. Jahrb. Wiss. Bot. goers IgIo. 63. True, R. H., The harmful action of distilled water. Amer. Jour. Bot. i 255. IQT4- i R.H., and Barter, HL HL, Absor iat = ant aL cue a ee : lecemer areas U.S. Dept. Agric. Bur. Pl. Ind. Bull. 231. — oo ——, The exchange of ee : one ni nt salt. Tee 2:25 - t917] BROOKS—PERMEABILITY 66. TRUE, R. H., and BarTLett, H. H., , The exchange of ions between t upinus d BRIEFER ARTICLES NOTES ON EFFECT OF DYES ON ENDOTHIA PARASITICA Some experiments were made in growing the chestnut blight fungus, Endothia parasitica, in a liquid medium to which stains had been added. The dyes were congo red, trypan blue, methylene blue, and neutral red plus 7 per cent NaCl, all “vital stains.”” They were added to a nutrient medium, Pasteur’s solution. This solution was not a particularly good one for the cultivation of the fungus. Congo red, trypan blue, and methylene blue were used in 1/1000 of 1 per cent solutions. The dilu- tion of neutral red plus 7 per cent NaCl was not known. This solution had been successfully used in the vital staining of some animals of the lower orders, and it was tried on the fungus by diluting it 1 cc. to 500 cc. of Pasteur’s solution. The cultures were started from conidia mixed with a little mycelium taken from a test tube culture. Record of experiments Conco RED (1/1000 of 1 per cent congo red! in Pasteur’s solution).— Conidia germinated and produced normal mycelium. The hyphae became red colored. When the cultures were 5 days old, hyphae and —— had the same color. Reaction of moduay acid to litmus paper- on +o pale Laiebeon. : almost colorless, andclear. Th li s acid to lit red colored mycelium which had been spreading steadily over the mote of the medium showed in sharp contrast. Seven days later the fully and normally developed fungus had produced pycnidia and conidia. The 1, and th ycnidia looked yellow. Under the ‘microscope, the color of the hyphae was red to a a opaque. The colored hyphae turned blue at once on being placed in oo oF per cent sulphuric acid and later lost their color. The pycnidiaon : being tested in sulphuric acid yerct reaction; some of — turned o : phe, eneaid aoe Ot . ‘Tryvan aioe (1/1000 of r per cent trypan? blue in n Pasteur’s ae ce tion).—All the conidia, stained a - = so that their — wes could 1917] BRIEFER ARTICLES 251 be followed readily. They swelled, germinated, and produced normal mycelia. The hyphae were a deep blue; the growing tips were opaque to pale blue. Their blue color deepened with age. About 12 days after inoculation the medium lost its blue color, turning light yellow; the blue hyphae with uncolored pycnidia floated on its surface. METHYLENE BLUE (1/1000 of 1 per cent methylene blue’ in Pasteur’s solution).—The majority of conidia did not germinate, but instead developed vacuoles. The hyphae produced did not stain, except when the cells were dead. The plasmolyzed contents of the dead cells gathered in a blue clump in the center. These isolated dead cells distributed throughout the mycelium gave it a pale blue color. While the cultures grew more vigorously than the controls, they did not grow as well as the congo red and trypan blue cultures. No fruits were produced. NEUTRAL RED (neutral red plus 7 per cent NaCl solution diluted I to 500 parts Pasteur’s solution).—A few conidia germinated and grew. The cultures were as good as the controls. No fruits. Hyphae un- colored. Controt (Pasteur’s solution).—Conidia germinated, produced mycelium, but no pycnidia. In the case of the congo red and trypan blue cultures, it was thought that the mycelium had gradually stored up all the dye in the medium. Neutral red and salt did not stain. In those cases in which methylene blue penetrated the cells, it apparently was fatal. The fact that the solutions containing the stains supported the fungus better than the control medium seems to indicate one of two things: eithex. the toxicity. : of the dyes in the conc used (with th Pp’ neutral — red and salt) was enough tobe a stimul the dy h ter- acted the elements in Pasteur’s solution inhibitive to the growth of the fungus and so allowed the mycelium a better development. _ ,* in a series of experiments with methylene blue, found the dye accumulated in the cell sap rather than in the protoplast of the . : cell. The substances which render the storage possibl always identical; the two which are best known a are e tannin and _phloro- glucin. Mycelium taken fi Presence of tannin and premed ay "There was no evidence of these . a. aed fear in the were cells. The eee —_ were ferric” : rous sulphate bd bong potassium bi 252 BOTANICAL GAZETTE [SEPTEMBER Mycelia growing in a congo red 1 to 200 parts maltose solution were examined to see whether the dye had accumulated in the vacuoles or protoplast of the cell. The mycelium had not behaved with methylene blue as with the two colloids, but this gave no indication as to the deposi- tion of the pigments. : The fungus grew in the solution, but not vigorously. The mycelium was so deeply stained as to be reddish black. Under the microscope the conidia and older cells of the hyphae were dark red, while the youngest cells were a pale pink. Treatment with 50 per cent nitric acid showed by its blue colored reaction that most of the pigment was in the walls of all the cells, only less in the younger cells. The hyphae were plasmolyzed with a NaCl solution and also by drying; the contracted protoplasm in the center of the cells was red, the cell wall looking white in contrast. This first was noticed in the younger cells, the quantity of pigment in the older cell walls having obscured the color of the protoplast, until the ‘last stages of plasmolysis had been reached. Sulphuric acid, nitric, or hydrochloric produced besides a blue color, what was thought might be _ a blue precipitate. These very small spots, seen with the oil immersion lens, were on the cell walls and inside on the plasmolyzed protoplast. Glycerin caused the color to stream from the mycelium. Sodium hydroxide, while it brightened the red, also caused the color to diffuse _ into the surrounding solution. Throughout all these reactions glistening white granules in the protoplasts could be seen. It would seem from these reactions that a great deal of the congo red accumulated in the cell walls, some passed inside the cell walls, where _ it appeared as though the protoplast had stored the dye in the form of minute granules. In the nutrient solutions containing congo red, the difference in ee eeity of hing to store stain was so marked that con- - ; t once. For instance, Penicillium sp., yeast, and a rod-shaped bacterium f 1 growing in them remained unstained until dead. It is suggested that Endothia parasitica (Mur.) A. and A. may bea - good subject for Se ee ee us RUMBOLD, Pinter, al L CURRENT LITERATURE BOOK REVIEWS The study of plants WoopHeap’ has published an elementary textbook of botany which seems to possess several features deserving better things than this tardy notice. It is a pleasure to note that emphasis is placed upon the work of plants and their relation ox the habitat. lpheiag is considered in relation to function, and the amount f microscopic i juced t ini The book is divided into 5 parts, the first ius Kea tela elk asivadto te tative organs, occupying 150 cae ig organs, gr here, as as before, attention is confined to seed plants. next 100 pa f the great groups of systematic ete including a east consideration of trees and shrubs. The final Portion is an introduction to the study of plant communities, inclding those of the roadside and cultivated fields. One of th of the book is the choice of so much material fr the common plants of the field and wayside. It is a relief to see such Aarichrompentind vo iets moka. s0 persistently in moet textbooks. C [ee . gs cipl as : nd pos es FURY SRE Re PRS that theexamples — eaptlepeieece the British Isles, ee adda as ee tunity of following wean tied rather than copying directly the — outlined in the text. This < gs will certainly make the _ book indi. bl to the teacher in search - ideas and fi x exerci s : with which to a a It wo a kh. 3 3, a ce ; critic - id oat they ane not on oa the whole serious defects. As an example, 7k ae oe ormal SS ee oe = o Cf 254 BOTANICAL GAZETTE [SEPTEMBER ‘The life of inland waters This book? = eo — _ an i Connery 5 —— a comprehensive view of our fresh forganisms. The viewpoint is essentially ecological, ak a background of economic possibilities. The first portion of the volume consists of an introduction to the subject, that is to the science of limnology, including a historical sketch of important in its development and a glance at the present facilities for study, which include some 30 biological field stations in the United States and Canada. There follows a discussion of water with respect to its transparency, tempera- ture, and circulation, as well as its gas, mineral, and organic content. The various types of — habitats are then presented. These include ponds, and bogs. , streams, In the consideration of aquatic organisms, $7 pages are devoted to plant and 83 to animal forms. Concerning the latter the reviewer will venture no opinion, but the paragraphs on plant life seem interesting and accurate, but so general that they would need to be supplemented by good teaching in the field to accomplish their purpose. In such an ecological textbook the adjust- ment of organisms to the varied conditions of aquatic life under which _ exist, and the interaction of the aquatic communities are, of course, the most ; important parts of the book, and considering the immensity of the field to be plexity of tl ial it would seem that the authors have been very successful. Still the book will have to be supplemented by a teacher with an unusually wide acquaintance with both plant and animal life in to teach the entire field effectively. Good illustrations and a fairly extensive bibliography add to the value of the volume.—Geo. D. FULLER. MINOR NOTICES m Fruit diseases—A recent textbook by Hester and Wanexsid discusses — from : _ the subject from an essentially New England viewpoint, omitting all ae t are of : t in many states and : a as Na ht ar of nes or pel oem The decom — = “Nemo, Jos Game Loe, J.7 T., The lie of inland waters. “8v0. = 8 : S. 244. ork: Comstock Co. I viewpoint rather oS =, ‘New York Botanic Garden. 1917. 1917] CURRENT LITERATURE 255 than of a general nature. This is especially obvious in the treatment of such diseases as apple rust and pear blight. The illustrations are poor. Such figures aS 29, 32, 40, 69, 76, 83, 86, 92, 98 are not worthy of publication. Throughout the book there is a tendency to present various conflicting ee si argu- ments concerning a given disease, with the result that often th if any, are buried or obscured. This really is the result of the status of pathol- ogy, of insufficient knowledge of the diseases in question, but the value of such presentation to the student: and especially to the practical grower is doubtful. sgtietg a central New York viewpoint and interest, the book may be said 0 give a very complete presentation of what is known of fruit diseases, with saat lists of references to original sources of information. It is, as the authors announce, the first American text to deal wholly with diseases of fruits, and here for the first time are brought together with comprehensive discussion many obscure and little-known diseases. The facts presented are well selected, and the book — a valuable addition to the literature of plant diseases. —F. L. STEVEN North American Flora.—The second part of Vol. 21 contains the presenta- tion of Amaranthaceae by. STANDLEY,‘ who recognizes 166 species distributed among 21 genera. Amaranthus is much the largest genus, with 42 species, followed by Iresine with 32, Achyranthes with 31, and Gomphrena with 15. These | contain = Seagate 166 species, the remaining 46 being distrib- uted among 1 era. w species, 10 in number, are described in Amaran- thus (4), Aoi F scart Achyranthes, Gomphrena (2), and Iresine.—J. M. C. North American Flora.—The second part of Vol. 10 contains the presenta- _ tion of Agaricales by Murritt, including the subtribe Pluteanae. The largest genera are Entoloma (63 spp.), Pluteus (57 spp.), and Leptoniella” c _ (43 spp.). Ten genera are presented, and 109 new species are distributed as follows: Claudopus, Eccilia (9), Leptoniella (14), Nolanea Gx, Pleuropus (7), Entoloma (34), Pluteus (30), Chamaeota, and Vela wnns @). J. M. c. es : NOTES FOR STUDENTS _ ee Anthocyans.—Since the review of the anthocyan (anthocyanin) moe by Crocker,’ much # ee een ee As ety out by C » these facts are of marked s e to ee : ical, Gicaicat a oA on ee Se ae : * STANLEY, Pak c, ‘North ie Flora ar: spart : 2 pp i i PORTS a co a w. cent North . American Flora ro:part 4. - PP. a a ric le 256 BOTANICAL GAZETTE [SEPTEMBER The bibliography is very complete and should stimulate further work. Brief reviews of the anthocyan pigments have pegged appeared by Artxins; Pveaesr, 9 encsamnrede SRI and WEst.” ti ithe ugar-free compound, obtained pon hy of th anthocyan with 20 per cent hydrochloric acid) has He definitely established by the synthesis of cyanidin (by the reduction of rectness of the formulas earlier proposed fy by sdeoevelien after studying the orides. The mechan- ism of the reduction of quercetin and other flavones to anthocyanidins has béen questioned by certain Japanese workers,’ who claim to have isolated various magnesium compounds as intermediate products. These criticisms, Bonever, 3 in no way invalidate the general conclusion as to the structure of the anthocyanidins. me | Cl 0 O OH wii Bee Sas HO Cyanidin chloride HO; oH. _ S Argmys, W. R. G., Research hysiology. Whittaker Co. 16 a 9 Everest, A. E., Science Progress i507. 914-153 eg Genetics 4 es a TOHETS. : es _® WHELDALE we 1 red Cua Se ue as: a. : Pog r ae a 1917]. CURRENT LITERATURE 257 The amyl alcohol test for anthocyans has played an mapesiant Part in the course of WILLSTATTER’s work. The anthocyan (glucoside) remains quanti- _ tatively in dilute (2 N) sulphuric acid when shaken with amy] alcohol, whereas the anthocyanidin (non-glucoside) passes quantitatively into the alcoholic "layer, yielding a red solution. When shaken with a sdlution of a enone the red color becomes violet or violet red, th in the amyl alcohol. On shaking with sodiuia ‘carbonate, the alcohol solution turns blue or bluish-green, and at the same time the pigment descends quanti- tatively into the aqueous layer. This is true only for diglucosides. Monoglucosides yield a certain amount © fas es Sc » the caaseedh ee Rhamnose glucosides (containing one ) behave like the monoglucosides. From thie ss is seeks the test may be used to distinguish nome- and rhamnose- glucosides from diglucosid The test is also of service in testing the individuality of anthocyan. For this the acid used must be of sufficient concentration to prevent the conversion of the colored chloride into the colorless carbinol (W base) and yet must be dilute enough to dissolve the chloride readily (0.5 per cent hydrochloric acid Two successive extractions with amyl alcohol are made, and the fraction of the sp aridcnin we mia agen Mace accia sere Scena wpe h ad in both cases : gi comprar: i solo ed three classes were found. Iti true thatthe possiblity of other clases is, again, not excluded. I preliminary work 27 isolation of several new a anthocyanidins may be expected. The one flower studied ed. however ae ae ia ge pom nd and ni te S : formula of chloride, the source from which it —S : fe They ai ad aan 258 BOTANICAL GAZETTE [SEPTEMBER The relationships of these various anthocyans and anthocyanidins may best be seen from the diagrams on page 259. TABLE I Anthocyan Formula. Anthocyanidin Occurrence ‘Sugar components Pelargonidingroup largonin . CHx0.;Cl | Pelargonidin | Scarlet red pelar- | 2 glucose 2 C he flower, orange red and dark os : violet dahlia Callistephin....| CaHaOy.Cl . Summer aster i ‘Galvan. * i SUR oe We. SS H,0,;C . Salvia es Salvin......... CzHz0,;;Cl1 os i Cyanidin group a Cyanin... CzHO«Cl | Cyanidin Cornflower, rose, | 2 glucose dark red garden dahlia | *Mono—or dimethyl ethers. Eo DORE meer oF ‘+ + + ek _ eyanidin glucosides have been isolated from the cine cree blue ete dP orSocasepteotise Aces of the flow . 1917] CURRENT LITERATURE 259 rubrum L., the raspberry, and the berry of the mountain ash. These glucosides also occur very extensively in fruits and in yellowish red, red, brown, and dark blue berries. They have been isolated from the cranberry, the cherry, the sloe (black thornberry), and the plum. The occurrence of a pure red coloring Pelargonidin group Pelargonin Callistephin Pelargonidin Cyanidin group 260 BOTANICAL GAZETTE [SEPTEMBER Haas” on this question. Determination of the total acidity and actual acidity by means of titration, and the gas chain and buffer solutions, shows that the reaction of the cells studied ranges from about Pa+3 to Pa+7. If we call the buffer solution acid up to Pa+7, neutral when at Pz+7, and alkaline when higher than Pu+7, it is evident that it is unsafe to call cell sap acid when - red, neutral or alkaline when blue, and markedly alkaline when green, unless the color changes of the particular pigment are first studied by some method, such as that of using buffer solutions of known hydrogen ion concentration. One other study may also be mentioned in this connection. These chem- ical investigations inspired a study by Sarpata, Nacat, and Kisuma*™ of the physiological and biological significance of the anthocyans and flavones in plants. The evidence: obtained established a somewhat unexpected fact, namely, that the flavone derivatives are one of the cell contents of very com- mon occurrence in the plant kingdom. In fact, they are quite as common as chlorophyll, tannins, sugars, starches, and proteins. They are not only found ae He yebow Dosing wiatter, but also in the cell sap of the epidermis and in the underlying tissu general jal: eal the lete ab f chr for example, in the white corn flower : (Centaurea cyanus), oxalis (Oxalis violacea), pink (Dianthus caryphyllus), and (Pelargonium cucullatum). The function of the flavone deriva- tives dissolved in the cell sap is to protect the living protoplasm and the important biochemical agents involved from the injurious action of the ultra- violet rays of sunlight by absorbing them at the peripheral layer of the plant ihe plausibility of this assumption is justified by an extensive study of th The green leaves of deciduous trees, which produce anthocyan pigments in autumn, contain a co considerable amount of flavones. The production of autumnal color is due to the bio chemical change, that is, the red flavones in the leaf, initiated by the physiological condition at the end of the growing season, with- out having special ecological significance. This brief survey of recent progress in anthocyan chemistry makes it seem very probable: that i in the near future we may have a complete based up dd f the chemical . ‘arachos @ tad akieip ee aa Tt ie to be boped that the work say ee any GEREN ea oe ee West. "Taxonomic notes Evans” ‘has ‘published a monog! aph of the North - 6 : bedi of Jama) sno. bolas = ten: — esc ae ue of Marchantia, recognizing 9 aes one of which (M.— 1917] CURRENT LITERATURE 261 by an account of the morphology of the genus. The detailed description of each species is accompanied by the synonymy, citations of exsiccatae, and.a very full discussion. In a revision of peace the same author™ discusses 4 species, 2 of which — are described as new. FERNALD” has described a new Cardamine (C. Longii) from Maine, which grows in “shaded rock-pockets and crevices covered at high tide.” In the description it is contrasted with C. pennsylvanica. MacKenzie” has described a new species of Carex (C. convoluta), which ranges from Maine to Manitoba and south to the Gulf States. Heretofore it has been included in C. rosea. PENNELL,* in continuation of his studies of the plants of the southern States, has described a new Smilax (S. leptanthera) from Georgia, closely allied to S. tamnifolia. RENDLE* has described a new genus (Maidenia) of Hydrocharidaceae from West Australia, belonging to the Vallisnerieae. Rocx,s in connection with the preparation of a monograph of certain genera of the Lobeliaceae of Hawaii, re oe et varieties of Cyanea, and 2 new varieties of Lobelia. Wrecanp* has described a new species of sects (E. peregrina), which Occurs as a weed in this country, as well as in Germany and Japan, and which — is unknown as yet in an indigenous state. It was separated from the well a2 es segue a apd pape tre coe ron donee es condensata Hackel.—_J. M.C. __ spore dete, Aree to ‘hae the ae as of sporophores of - rr cme igh ts 44:191-222. pl. 8. 1917. ce “Pasa, M.A new Caromine rom stern Maine. odors 1898 - 92. 1917. — ee 3 PENNELL, F. ful, Eeveaa en apeunems eRe < Torr. Bot. Club 432412. 1916. : - -* Renpie, A. A. By Maidens, «new genus of 2 eens ol. 545. 1916. * MacKenzre, K. K. Notes on Carer. x. Bull. Torr. Bot. Club 431428. nea — 262 BOTANICAL GAZETTE [SEPTEMBER some species of Fomes consists of true basidiospores which have been carried upward by gentle currents of air, such as arise from differences of temperature at different levels, and have lodged on the pilei. In support of this view the author points out that other objects in the vicinity of the fungi also become covered with spores. A simple experiment lends further support to this view. Pieces of cardboard pinned on the surface of sporophores of Polyporus applanatus in May were covered with spore powder in July, as were also. all portions of the surfaces of the fruit bodies except the areas covered by the paper. While not venturing to explain the pertinaceous adherence of the spores to surfaces, the author suggests that they stick fast by virtue of a gelati- — cutin layer. Regarding the spore powder on the surface of these fungi, have generally adopted the view of ScHuLzER, according to which the Sede consists of conidia whose origin on the surface of the pileus is - minutely described by him. Although opposing the view of SCHULZER, Romett does not speak of repeating the histological examination of that investigator. If the explanation of RomeLt is correct, it is a matter for inquiry _ why this peculiarity of spore distribution is restricted to a few members of the _ genus Fomes and does not occur more generally among the Hymenomycetes. Even among the caespitose Agaricaceae, only those parts of the pilei over-— =— by others are soely cat bs spores, while the exposed parts as Journal of Forestry.—With the issue of January 1917 the Journal Ae Forestry takes the place of the Proceedings of the Society of American eo | _and of the Foresiry Quarterly. This change of either a aspaige by the other, but rather an amaigamaton ofthe best feaeres of BE : — “pages per annual volume. ste ‘Original Publications i is intended. In continuing — the activities 08 wthath Soo to the LAC YP WER WEE Oe oe Te it mah fhe eu ts igh tna of _ which promises well for its future. oe oo ‘Some aig of 30 years of forestry work of the Federal Government P 1917] CURRENT LITERATURE . 263 It is safe to predict that the new journal will be of increasing interest to all botanists, and more particularly so to ecologists who see in forestry the practical application of their more theoretical studies —Gro. D. FULLER. Endemism and the mutation theory.—WILLIS, in papers previously reviewed in this journal,” working upon the flora of Ceylon, has proposed the theory that relative endemism is determined by relative age, the youngest species being the endemics. RIDLEY’ points out that Wituis has based his arguments upon statistics gathered from herbarium specimens; and illustrates that such will not agree with field statistics, the commonest species sometimes being poorly represented in the herbarium. In connection with his theory Witus States that “very common” plants could not disappear without a i Rp common species have disappeared within a few years, due to parasites, the activities of ae and Eeavey: in climatic changes. Eoaae Gaines} a the Ceylon 1 they could have been evolved recently. The remainder of the paper is a criticism of the mutation theory as used sea to explain the origin of the Ceyon flora. Rip_ey’s arguments and theory, or WILLIS’ application of it, the paper is unconvincing to the . reviewer.—MERLE C. CouLTER. ‘icin eld amis “Fincoe® tx Accs 4 Mecca ew ot Norfolk and Suffolk Counties, England, where upon sandy soil with only 22.5 dominated _ ovina and Agrostis vulgaris are the most abundant species. ‘The sterility lity of : o S rere desta that some has never been cultivated and much of the restonce o ides is. a. i . es Great Britain In the second of his Papers. the author finds that the chief factor in : ae 264 BOTANICAL GAZETTE [SEPTEMBER the Calluna maintains its dominance over both the grasses and the lichens. — Geo. D. FULLER. The variable desert.—Writing in semipopular language, Harris’? has described the wide variation of climatic and other factors infloenchig plant life in the desert region of Tucson, Arizona, in such a way as to give a more graphic and living a - this most interesting region than will be found in other more vol lreports. The wide variation of precipita- tion from year to year and from month to month is made clear by a diagram, while the large proportion of waste of the scanty water supply is emphasized. The wide range of temperature during both the year and the day, the almost urge: ‘qeeeed o pat forms, extending from thin to thick-leaved herbs, from hrubs, and from succulent to woody plants with varied aspect at different seasons of the year, are all clearly depicted. In a word, the reader is made to appreciate some of the complexity of environment and diversity of organisms which have rendered this region so fascinating to the intelligent layman and to the investigating scientist.—Gro. D. FULLER. : Ecology of lichens.—In connection with a systematic study of the lichen flora of South Lancashire, WHELDON and Travis* discuss some of the factors detrimental to the growth of these plants. Particular attention is directed to their sensitiveness to pollution of the at ical fumes attendant upon the development of a | mnautactacag industry. The observations are of a general rather than of a particular character and are not — —— by any experimental data. They also note that a calcareous substratum ratum seems to counteract the effect of smoke upon the lichens. = oe 4 baciciangh - scarier r | 7 to the carboniferous limestone.—Gro. D. FULLER. =r? ws? rt ‘i... Ate L E ea tae sly OR ee st £. : per commoner yas Ciedoagengeaaey Burns concludes that “‘toler- ance: Uaed te experas.& light relationship should no longer be used in reference te pment seedlings. He found the filtered light in the forest. ee pea a es zy +s , nm di ide com i with the w k- og . ened white light. in vay mau gh cp may ge oe ae oe ae SORES 1 eS D.1 ig ‘ a J. Anruve, Ths tie st Scientific ¢ Monthly 341-49. 16 ee 33 WHELD A., and Travis, W. G., The lichens of South Lancashire. Jour . Lina. Soe. airih 1QT5. _eBems, GP, Std intolerance of New England forest is om continuous light in forests. Vt Sta. Bull. 193. pp. 23- 191 VOLUME LXIV NUMBER 4 THE BOTANICAL GAZETTE OCTOBER 1917 _ NOTES ON BULBIFEROUS FUNGI WITH A KEY TO DESCRIBED SPECIES J. W. Hotson (WITH PLATES XXI-XXIII AND SIX FIGURES) Introduction hs has been shown in a former article (6), the term bulbil, as _ applied to fungi, refers to reproductive bodies of more or less definite form, composed of a compact mass of homogeneous or heterogeneous cells which may be few or many in number, but which are usually developed from primordia of more than one cell. This mode of reproduction is common among certain fungi - and constitutes the only known means among others. Many _ Of these structures superficially resemble the “spore-balls” of _ Urocystis or Tuburcinia among the smuts, but differ from them in their manner of germination. In general appearance and mode — of development the bulbils of Papulospora spinulosa Hotson might — readily be taken for “‘spore-balls”’ of Urocystis, but, on germination, ae Promycelia bearing sporidia such as are produced by” the smuts are _ re oe _yet unconnected with a perfect form are added to those a 266 BOTANICAL GAZETTE [ocroBER Stephanoma strigosum Wallr. the superficial cells are produced in a manner similar to those of certain bulbils. Mature bulbils may also resemble sclerotia. The latter, however, may be regarded as the result of the irregular massing together of vegetative filaments, the individual cells of which do not partake of the nature of spores either in appearance or structure, while in the bulbil those cells that are filled with protoplasm usually act independently of each other, in this respect resembling spores. There are a number of sclerotia of the simpler type, such as are produced by Penicillium italicum and its allies, which are small and more or less regular in form and outline, somewhat resembling bulbils in appearance. The mode of development of these sclerotia, however, consists in the irregular massing together of the vegetative filaments, as has just been mentioned. Before 1912 the literature relating to bulbils dealt with less than a dozen described forms. Most of these were referred either to the form genus Papulospora or-to Helicosporangium. Owing to the fact that the limitations of these two genera were not clearly defined, it was thought wise to redescribe the genus Papulospora (6), and to group all those fungi that produced bulbils, but whose perfect condition had not been obtained, into this form genus. The literature on this subject has been carefully reviewed in the article already mentioned. This article shows clearly that these fungi do not belong to any one of the natural orders, nor do they in any sense form a group by themselves, but occur without regularity as imperfect forms among the main groups of higher fungi. The forms, associated with bulbiferous Sains mentioned in that article, include among the Discomycetes a new species of Cubonia, este the Hypocreales 3 species of Melanospora; among the ee idiomycetes at least 4 types; while 9 species of Papulospora as — o 2 : pie Among the latter, Bie; ees. candida Sace. eee . 1917] HOTSON—BULBIFEROUS FUNGI 267 According to his account, the bulbils resemble the compound spores of Urocystis among the Ustilaginales. The color of these Urocystis-like spores is reddish to chocolate brown, their form more or less spherical, the cortex being a layer of empty, colorless cells. The size of the spore balls, however, is not given. They apparently resemble the bulbils of Melanospora papillata Hotson, but the perithecia of the two species are different. In M. marchica the perithecium has no papilla, the setae arising from the flush surface of the wall. The perithecium of M. papillata, on the other hand, has a distinct and often quite prominent papilla, the terminal setae being produced at its tip. The bulbils of M. marchica also resemble those of Papulospora coprophila (Zukal) Hotson, but vary some- what in their mode of development. Apparently NEcER had not seen the writer’s article dealing with bulbils (6) or that of BAINIER (x), and therefore makes no comparisons. Recently DopcE (3, 4) has reported a species of Papulospora closely associated with Ascobolus magnificus Dodge. He is of the opinion that this is either a parasite on or an asexual spore form of the Ascobolus. These bulbils are light brown, with a layer of __ empty cells forming the margin. A description of this fungus is — 0 in the present article under the name of Papulospora mag-— fe has been shown in a recent article by Mexavs, RoseNpaum, 6 and ScHuttz (8) that a spec ing bulbilsis ' frequently associated with the powdery sc > of potatoes (Spongo- iS Spora subterranea [Wallr.| Johnson). These investigators have isolated P. coprophila (Zukal) Hotson from tubers infected with ee — This organism has been shov F experiments to be a anes arse a 268 BOTANICAL GAZETTE [OCTOBER The substrata were put in moist chambers, and as the bulbils appeared they were picked out with sterilized dissecting needles and transferred to tubes containing nutrient material. Description of species Bulbils are in all cases to be regarded as imperfect conditions of higher fungi. As has already been indicated, some have been definitely connected with perfect conditions belonging to widely separated genera of both Ascomycetes and Basidiomycetes. Those, however, that are to be considered in the present article have thus far baffled every effort to induce them to produce any perfect form, even after 7 or 8 years of cultural study. Two of these are doubtless ares since their mycelia possess clamp connections, while sh me evidence that it belongs to the Pyrenomy- cetes. It is the aim of the present article to contribute further information regarding the occurrence, morphology, and develop- ment of bulbils, and also to bring together the described species in the form of a key to the genus Papulospora. ospora pallidula, n.sp. (figs. 1-16; text fig. 2). —Mycelium white, procumbent, scanty on most media; bulbils colorless, becom- ing pale yellow when old, somewhat spherical, 70-100 » in diameter, sometimes elongated to 1404; primordium of two kinds, one 4 short lateral branch which divides dichotomously of 3 or 4 orders, | occasionally more, and the other a group of intercalary cells. No other means of reproduction at present known. On trois colearre oi Soe ane ete Gentoo and Claremont, California; also on rabbit dung from Ontario. The substrata were put into moist chambers and, when the bulbils appeared, transfers were made, eventually producing pure cultures. ee a — ind Sead potas such as ue ae eas : : 1917] HOTSON—BULBIFEROUS FUNGI 269 is true with many other fungi, the abundance of the mycelium depends largely upon the kind of substratum. On potato or goat dung agar it develops very sparingly, often becoming quite difficult to detect even with a good lens, while on bran or cornmeal agar | it becomes more conspicuous, growing evenly over the whole sur- face of the culture and on the sides of the tubes, but never becoming very flocculent. On appropriate media such as horse dung, bran, or cornmeal agar, the mycelium forms a thick felted layer over the substratum. Most of the hyphae are small, about 3-5 u in diameter, but some of the older ones become as large as 10 », with prominent cross walls. They are frequently packed with large oil globules (fig. 1). Here and there in the hyphae swollen cells appear that are full of food material. These are oval at first, but eventually become almost spherical. DEVELOPMENT OF BULBIL.— A short lateral branch divides dichotomously, producing dichotomies of the second, third, © or sometimes of the fourth order (figs. 2-6). These branches divide into short cells which enlarge, eventually forming the central ones of the bulbil. As these cells grow they become more compact, and from them by a Process of budding others are formed which increase in size, oming closely and compactly pressed against their neighbors Fic. adeno preneaey ine, (figs. 7-0). This mode of development usually produces mature bulbils that phates Kah gus anieiiie magne ae URI So 70-100 mw in diameter (fig. 13). o — _A second mode of develop ent of the bulbil is arenes os 270 BOTANICAL GAZETTE [ocTOBER pale in color is formed, with several large cells in the center which are conspicuously filled with oil globules. These bulbils are usually more or less spherical, but not infrequently become elongated, as shown in text fig. 2, which shows a group of bulbils, the longest of which measures 78 by 140 uw and is probably the result of the fusing of two immature forms. These bulbils germinate readily in water. Fig. 13 shows a germinating bulbil 75 by 67.5 u in diameter after 24 hours ina Van Tieghem cell. The young hyphae, which have a large number of oil globules, are usually produced from the larger cells, but “y cell is capable of germination. Occasionally as the bulbils grow older the cells composing them adhere less firmly together, becoming more and more like indep with the development of the bulbil of Papulospora polyspora Hotson (6), which in turn suggests a similar condition — found in Aegerita webbert Fic. 2.—Group of bulbils of P. pallidula. ae few of these loosely con- nected cells germinating, which seem to act independently, li | spores : His ‘eel that one of the primordia just described is that 2 of the perfect stage, but for some reason it fails to ae SS a found, as if an effort were pelos: made sg the fungus to pr — ro ae oS _ the perfect ain Thee far, Teapeee none > of these a ae Faweett (5). Fig. 14 shows @ 1917] HOTSON—BULBIFEROUS FUNGI 271 in form, 100-250 u, occasionally elongated to 350 in diameter, produced in fluffy aerial clusters; primordium one or more short lateral branches twining spirally about the main branch. No other means of reproduction at present known. On horse dung, Kittery, Maine; Seattle, Washington; St. Louis, Missouri. The original material from which pure cultures of this fungus were obtained was found on a horse dung compost at Kittery, Maine, by Dr. Tuaxrer. It has since been found by the writer on similar material in the vicinity of Seattle; also on material sent from St. Louis, Missouri, by S. M. ZELLER. In the last instance the bulbils apparently were produced after the horse dung compost had been used as a fertilizer on mushroom beds. This fungus has never been found on any other substratum than horse dung. It has been grown on different media in pure cultures for 6 years without inducing it to produce any other fructification than bulbils. _ The mycelium is white, 3-5 u in diameter. It is usually pro- cumbent, but when cultures are left in such a position that the hyphae can grow straight downward they grow out into the air, producing long streamers or festoons which attach themselves to the opposite side of the test tube. _ The bulbils of P. byssina resemble those of Grandinia crustosa, . 7 but the two species can easily be distinguished by the prominent liut n of the latter. Even the general ae appearance of the mycelium i in cultures i is sufficient to distinguish © them, Grandinia producing a) Cae tee et 1s, . i“ oe Strands of hyphae which radiate conspicuously in all directioan ae from the point of inoculation.” This phenomenon is entirely Boe absent in P. byssina. The cells composing the bulbils are homo- geneous throughout. In this respect ‘they resenible those | of 2 o 272 BOTANICAL GAZETTE | [OCTOBER (fig. 17), which may send out other lateral branches near the first (fig. 19). This branch may also take part in the formation of the bulbil. The cells of these various branches increase in size and become well supplied with food material. From them short lateral branches are produced which either intertwine among each other, or if very short assume the form of new cells as if produced by a process of budding or gemmation. Fig. 20 shows the primor- dium of a bulbil in which the secondary branches are being pro- duced. These will eventually intertwine with each other in a more or less wormlike fashion, as shown in fig. 21, an immature bulbil 44min diameter. The first lateral branches that twine around the primary filament may become localized, in which case the mature ~ bulbils will be somewhat spherical, as shown in fig. 22, which represents a bulbil 110 uw in diameter. More often, however, the spherical bulbils are produced in a slightly different way. Not infrequently a terminal branch coils up and winds back on itself, or it may divide dichotomously, both branches thus formed twining back on the main filament (fig. 18). A primordium of this sort develops in the same way as the one already described, by the intertwining of lateral branches. The mature bulbil, however, tends to be more spherical than that in which a lateral branch _twines about the primary filament. Occasionally several bulbils _ may be produced from the same filaments, as is indicated in fig. 24, which shows the bees of 3 bulbils at a, b, and c respectively. _ Ata the seconde : are beginning to be formed in a manner _ siitilar 40: that shoe ta he. 20. It is possible that a and 6 will merge into one, forming an elongated and more or less irregular bulbil (text fig. 1). Owing to the variation in the mode of develop- ment, a great diversity of form is produced. Text fig. 1 i BE | _ a group of bulbils showing this wide variation of form. The exact _ dimensions of these bulbils vary from 112.5 to 338 m, but occasion: ally even a greater difference than this is observed. 2 fe test the germinating power of these fruiting bodies, hanging a iS = were made i in Van a cells. It was found ne in me 2 cron wares tne pee 1917] HOTSON—BULBIFEROUS FUNGI 273 Papulospora aurantiaca, n.sp. (figs. 25-38; text figs. 3, 4).— Mycelium white at first, becoming yellowish with age, procumbent, scanty on most media, densely filled with oil globules, clamp con- nections sparingly produced; bulbils pale yellow, becoming orange, nearly spherical, frequently aggregated, 100-250 in diameter; primordium a spiral of one or two turns. No other mode of repro- duction at present known. On bark collected by Dr. THAXTER near Port of Spain, Trinidad, W-I. Fics. 3, 4.—P. aurantiaca: fig. 3, mature bulbil; fig. 4, several germinating bulbils. The mycelium of Papulospora aurantiaca is somewhat incon- spicuous, the hyphae being small, usually about 2-5-3 .5 u in diam- eter, and scanty. On certain media, like cornmeal or bran agar, it omes more marked but never profuse on any media tried. These included such nutrient material as potato, sugar, bran, cornmeal, prune juice, horse dung, various kind of wood, etc. The hyphae contain large numbers of oil globules which vary considerably in size. When the filaments are crushed these float out into the water, a number frequently fusing together and some- _ _ times forming large spherical globules 17.5 # or more in diameter. Many and varied experiments have been made in the hope of - causing the fungus to produce its perfect form, but thus far all oo __ efforts have failed. That it is a Basid dily seen by Ae presence of os connections in the myelin. a : 274 BOTANICAL GAZETTE [OCTOBER small, more or less inconspicuous, and sparingly developed. There are a number of basidiomycetous forms that produce bulbils as an imperfect condition. In a former contribution (6) the writer has referred to 4 such species, and in the present article 2 additional ones are described. The reddish orange color of the bulbil under consideration readily distinguished it from other species having clamp connections. The bulbils of P. nigra and P. anomala are dark brown or black, those of Corticium alutaceum chocolate brown, and those of Grandinia crustosa straw colored with conspicuous clamps. Samples of the fruiting bodies of Sporodesmium aurantiacum — B. and C., collected by Dr. THAXTER at Cranberry, North Carolina, in August 1889, were obtained from him for comparison with the bulbils of P. aurantiaca. As these structures were too old to germinate, a comparison of their mode of development could not be'made. The fruiting bodies of the two fungi resemble each other so closely in their general form, color, texture, etc., however, that there is little doubt but that they are identical. DEVELOPMENT OF BULBIL.—In common with many other bul- bils, those of P. aurantiaca begin by a short lateral branch coiling - up spirally. The early stages in the development, with some of the variations, are illustrated in figs. 25-38. During the process of - coiling, which seldom results in more than two turns, the individual cells comprising the primordium become well supplied with food material and often appear distended (figs. 26, 27, 29). From the cells composing the coil short branches are developed (figs. 27, 28, ay, 0); Thee secondary branches may twine about each other or they may enlarge, forming cells that resemble those ahteneirn oe _ by a process of gemmation in other bulbils. These short b a : and cells continue to be formed, sometimes on the concave side of ae rve e: on wae convex side, until i all trace bee | and | 1917] HOTSON—BULBIFEROUS FUNGI 275 the fruiting bodies of Sporodesmium aurantiacum B. and C., already mentioned. In their early development the bulbils are usually very irregular in outline, owing to the projection of secondary branches which become less prominent in the mature form. Frequently the bulbils appear as orange or yellowish patches scattered over the surface of the culture instead of being distributed evenly. This is due to the fact that the primordia are often pro- duced in large numbers on a single branch, as shown in figs. 35, 36. As these develop, a corresponding number of bulbils are produced, which adhere together for a considerable time, superficially Fics. 5, 6.—P. nigra: fig. 5, group of ee bulbils; fig. 6, , group of mature bulbils, showing general form and variations in size. resembling sclerotia. As a rule, these bulbils develop very dooty, ; usually taking several months before they mature. Eventually, however, as the substratum becomes dried up, the individuals Separate into powdery, orange colored masses. The bulbils germinate readily in nutrient fluid, several - which are shown i Se text fig. 4. Papulospora nigra, n.sp. Poe 40-47; Noe ey 5 6) Mycelium Ee : white, procumbent, scanty, oil globules and clamp connections _ Conspicuous; bulbils colorless at first, becoming dark brow: black, nearly spherical, roo-180 in dane at maturity; pri- : sims one or more short lateral, peace: which coil up 276 BOTANICAL GAZETTE [OCTOBER On old cardboard, Cambridge, Massachusetts, and on hardwood chips, Seattle, Washington. Papulospora nigra was obtained from gross cultures of old - cardboard in the cryptogamic laboratories of Harvard University, and on similar cultures of chips in the botanical laboratory of the University of Washington, Seattle. When the bulbils appeared, pure cultures were made in a manner similar to that already described. This species has been grown on a variety of media for 8 years without the perfect condition being obtained. The myce- lium is white and remains so throughout the period of rapid growth. Only when the hyphae get old do they begin to change color, becom- ing brownish or smoke colored. The primary mycelium is pro- cumbent and on most media is inconspicuous, but becomes more or less flocculent or cobwebby on bran or prune agar. When 4 culture becomes old, the whole surface is covered with black bulbils which completely obliterate the mycelium. The hyphae frequently contain many large, conspicuous oil globules (figs. 40-42). The mycelium also has quite prominent clamp connections, a condi indicating its relation to the Basidiomycetes. The bulbils of this species resemble closely those of P. anomala Hotson (6) in size, form, and color. They are readily distinguished, however, by their mode of development. In the latter species the _ bulbils arise from ‘‘slightly swollen, colorless, intercalary cls . . - . about 4 or 5 w in diameter, sometimes projecting consider- ably and resembling short stunted branches; at other times _ base of a short lateral hypha swells slightly and forms the primor- dium.” From these primordial cells branches are sent out in different directions, the lateral walls of the basal cells adhering — firmly together and becoming eventually incorporated into the bulbils. It will be seen that the development of the bulbil of = : P. nigra is quite different from this. It has already been shown may readily be distinguished from those of Corticium alutaceum, — . 2 thos of Grandinia ersten by t a oe ation of P. aurantiaca that the bulbils of P. mgr 1917] HOTSON—BULBIFEROUS FUNGI 277 are developed which intertwine, sometimes incorporating the primary filament. If the lateral branch divides, as it not infre- quently does, the two filaments thus formed coil up, and these with those that are subsequently produced from them intertwine (figs. 44, 45). During the early stages of development the cell walls are usually clearly distinguished, but as the bulbil grows they become more or less transparent and quite indistinct (figs. 45, 46). At the stage represented in fig. 46 the whole bulbil is color- less, the cells containing a large number of oil globules, which con- dition continues until almost maturity, when they begin to turn brownish. The walls gradually become more pronounced, and on account of lateral pressure they assume a more definitely angular condition. As the bulbils increase in size they become more and more spherical, so that at maturity they have a clear cut, even margin. Text fig. 6 represents a group of these bulbils. Although they vary considerably in size, the general spherical form and even outline is maintained throughout. Sometimes elongated, irregular bulbils are formed when two primordia happen to be close together and fuse as they develop. These, however, are the exceptions, and the cause of their abnormal condition can usually be detccted. If the bulbils are produced rather sparingly or away from each other, they invariably become spherical. These b iti ‘dia Vans Ticgliens cell or in a watch glass. Fig. Sheed ie eee we = ae, Oe ee ataeter, after 48 hours in a hanging drop. Text fter 3days. It may be noticed Mike as sok we i coe 6. = i: 20 eo iPaeleny as the hyphae are produced, the eve eee ineved aside and disarranged, pent when ne 278 BOTANICAL GAZETTE [OCTOBER In June 1915 the writer obtained a pure culture of Papulospora magnifica from Dr. B. O. Dopce for identification, with permission to make a cultural study of it. The fungus was originally found in New York City in April 1912, associated with Ascobolus mag- nificus Dodge, growing on horse dung in moist chamber cultures. Donce (3) is inclined to consider this as parasitic on the mycelium of A. magnificus, having traced ‘‘a direct connection between the mycelium of the parasite . . . . and the mycelium of the host.” He also shows by figures this definite connection. In a later statement (4) he suggests that the Papulospora may be anes, with Ascobolus magnificus “either as a parasite or as an spore form of the Ascobolus. If the former is the case, the ee of the parasite is intrahyphal; if the latter is true, then the phe- nomenon known as ‘Durchwachsung’ is extremely complicated in the mycelium of this Ascobolus.”’ As has already been indicated, bulbils must in all instances be regarded as representing imperfect conditions of the higher fungi; and, like the members of other more or less clearly defined form genera, may be associated with perfect conditions included in wholly unrelated genera of the Ascomycetes and Basidiomycetes. A bulbiferous condition has been found associated with the genus Cubonia (6) belonging to the same family as Ascobolus, so that it is not inconsistent with the general characteristics of the form genus _ Papulospora to consider the bulbils of P. magnifica as an imperfect — condition of Ascobolus magnificus. All efforts, however, have failed to obtain the ascocarp from pure cultures of the a although repeated attempts have been made to do so by growing : the fungus on a great variety of media which were exposed to differ- _ ent constant temperatures. Although the majority of the species: oe of sib ehiesters are. > undoubtedly saprophytic, there are some stb by Riecae (7) as parasitic on beets, while Cosranrty (2) se - described P °. dalliae as connected with the roots of dahlias, pens P. parasitica (Karsten) BH was de eventually develops i 1917] HOTSON—BULBIFEROUS FUNGI 279 definitely traced for some distance inside the filaments of Ascobolus magnificus, we are led to the conclusion that the fungus under consideration is parasitic on the latter rather than that the bulbil is the imperfect condition of it. On all the cultures made of P. magnifica the mycelium grew very sparingly, being procumbent, and at times growing down into the medium, but never becoming flocculent or aerial. On potato, bran, prune, and cornmeal agar only a small amount of mycelium was produced even after several months. So meager was the development that it might easily have been overlooked unless examined carefully with a hand lens. Of the different media tried, a decoction of horse dung with agar or the horse dung itself, sterilized in an Arnold’s steam sterilizer, proved the most satisfactory. A microscopic examination frequently showed the mycelium to be a network of anastomosing hyphae (fig. 69), while at other times (figs. 65-68) enlarged food storage cells were found, the largest being 15 » in diameter. DEVELOPMENT OF BULBIL.—The primordium of the bulbil is quite easily recognized as a short lateral branch, somewhat coiled _ or curved and well filled with copmurond ee vi cae develop- . ment the bulbil seldom, if ever, p , such as does P. parasitica, which it acet closely resembles. From the _ end of this coiled branch a cell is cut off, enlarges, a becomes well filled with granular food material (figs. 54, 55). This cl a PO ee | bil. © ; nt tha = Aas eda tis iced beac oes oo all epresel . Wes: St: <5. wile ut other Gel « secondary Wrctic & renee from it (figs. 50, 52). The usual mode of procedure, however, is ee that Shown i in see te 49» 54, 55- At may be seen that the end © oo 280 BOTANICAL GAZETTE [ocTOBER laterally. In the course of development these outer cells lose their protoplasmic contents, although the walls retain more or less of the brownish color. Although the foregoing description of the mode of develovae! of the bulbil is the usual one, not infrequently a second large cell is formed by the primordial branch (figs. 62,63). In such instances the further development is practically the same as where there is a single central cell. The lateral branches which eventually become the cortex are produced from both the large cells, which subsequently become completely surrounded, precisely as in the case already described. | Germination of bulbil The bulbils of most of the species of Papulospora germinate with little difficulty. All of those described in this article, with the exception of P. magnifica, have been found to produce rs tubes quite readily. In the study of that species various were employed in the hope that a favorable condition might be ound for the germination of the bulbils. Among these were bran, potato, and prune agar, various synthetic media, as well as decoctions of horse dung used both as a liquid and associated with agar, but all these failed to produce the desired result. Finally a method that the writer had found successful in in- ducing the ascospores of certain species of Ascobolus and Cubonia — (6) to germinate was tried with some success. Mature bulbils were put on a flamed glass slide and carefully crushed with the ‘flat surface of a scalpel. They were then transferred to hanging drops of nutrient media, a sterile decoction of horse dung proving : the best. Many of the bulbils thus crushed were totally destroyed, _ but in a few instances, where the pressure was just sufficient to _ break the cortical layer of cells without injuring the large central i one, germination was ‘produced and a branching filament soon developed (fig. 39). ce 7 "The mature ball of P- magnifica, with one or two large ceminal ? os surrounded by empty cortical ones, superficially resembles - co sate ste of 2. enone ay, Hotson. The latter, el : 1917] HOTSON—BULBIFEROUS FUNGI 281 spiral primordium of P. coprophila and the flocculent and abundant mycelium differ widely from those of P. magnifica. The bulbils of P. magnifica more closely resemble those of P. parasitica (Kar- sten) Hotson than they do those of P. coprophila. However, in P. parasitica, which is described as parasitic on beets in the original description by Karsten, the mycelium is flocculent, the bulbils 15-21 w in diameter, with a single large central cell invariably present, and the primordium a spiral which coils crosier fashion. Thus, the procumbent and scanty character of the mycelium of P. magnifica, as well as the size and mode of development of the bulbil, readily distinguish it from P. parasitica. In order to obtain further information regarding the relationship of these two fungi, inoculations were made in the roots of growing beets and turnips, both in the field and in the laboratory. In each case a small slice of the root was removed with a sterile knife and a cavity made in the cut surface. From a pure culture of P. magnifica a portion of the nutrient agar containing bulbils and mycelium was gouged out and deposited in this cavity. Over this a small piece of — glass was put and the soil replaced. Although several similar experiments were carried on, no indication of a parasitic condition could be detected. Other species that resemble the two just mentioned, such as _ Physomyces heterosporus (Monascus heterosporus [Harx] Schréter), oo Dendryphium bulbilferum Zukal, Acrospeira mirabilis Berk. and Br., etc., have al discussed (6), so that it is not necessary to repeat the discussion. , Key to species of bulbiferous fungi __ There are several more or less well defined characteristics that _are made use of in making the following key for the members of t . a form genus Papulospora. A broad division sexily made on the ae 282 BOTANICAL GAZETTE [OCTOBER cells, a single lateral branch, or a group of vertical hyphae. Using these characters as a fundamental basis for separation, the described species of bulbiferous fungi may be distinguished as follows: Hyphae with clamp connections Bulbils dark brown to black Bulbils 65-80 yw in diameter, chocolate brown. ...... Corticium alutaceum — 125-175 » in diameter, dark brown or black; margin even Premorinim toteriaey ek eke ee Papulospora anomala Piemonte ie. Papulospora nigra Bulbils light yellow, 52-88 w in diameter; hyphae ae ropelike andinia crustosa gpa yellow, becoming orange, 100-250 » in diameter; hyphae formed UI oo a Papulospora aurantiaca tikes without clamp connections Bulbils colorless, pale yellow, or cream colored Bulbils cream colored, 30-35 » in diameter; parasitic on Geoglossum Papulospora candida Bulbils colorless or pale yellow, 79-100 pt in diameter, saprophytic Papulospora pallidula Bulbils steel gray, 21-36 » in diameter............... Papulospora cinerea —Bulbils black or smoke color ce Bulbils 75-100 » in diameter; margin even..........- Cubonia bulbifera Bulbils 200-300 p in diameter; margin a ..Papulospora pannosd Bulbils yellowish red to dark brown a ‘Bulbils scanty; perithecia u inate present — hecee = with neck and lateral and terminal setae Melanospora cervicula _ Perithecia with papilla and terminal setae... .. . Melanospora papillate Bulbils abundant; perithecia — t Primordium intercalary ee ee cites] cells sag rence Papulospora immerso Bulbils straw color; central ols 10-20 pw in diameter Reser ‘ripe -Primordium one or more lateral branches oC oe "Cells of the bulb beteroencos; cortex definite ce tee _ Normally only - ~ Cortex complete - - ae ne S —— pocumbent bulbil a sr-s0n in T917] HOTSON—BULBIFEROUS FUNGI 283 Mycelium abundant, flocculent; bulbil rs5—21 be in diameter; iigieie: 1-celled. . . Papulospora par Cortex moomilete. . 2-5. 4, co Acrospeira mirabilis Normally more than one central cell Spiral in one plane; cortical cells spinulose Papulospora spinulosa Spiral normally in more than one plane; not spinulose; 2-6 central cells Bulbils dark brown... 2. ........., hase coprophila Bulbile brick ved... 5 ok, Papulospora rubida Cells of bulbil homogeneous throughout Bulbils chocolate brown, 21-36m in diameter, producing Sporotrichum spores........... Papulospora sporotrichoides ‘Bulbils straw color, 100-2 oe ree Papulospora byssina Primordium not spiral; bulbils large, fecaulan 100-750 p in diam- Os a Papulospora aspergilliformis Primordium two or more lateral branches forming a spherical aggre- gation of cells at the top... .............. _- Papulospora polyspora UNIVERSITY oF WASHINGTON SEATTLE, WASH. 1. Bainter, G., Evolution du Papulospora aspergilliformis et étude de deux Ascodesmis no uveaux. Bull. Soc. Mycol. France 23:132. 1907. 2. CosTANTIN, J., Note sur une Papulospora. Jour. Botanique 2:91. 1888. 3- Donce, B. O., Artificial cultures of Ascobolus and Aleuria. “Mycologia 4:218-221. ois. 2. 1912: , The Pi Papulospora question —— to Ascobolus. Science NS. : 4t:173. 1915. 5- Fawcert, H. S., An important entomogenous fungus. "Mycologia 25164. IQIo. gc ter ul , Culture studies of fing) producing ‘bulbils and similar Proc. Amer. mene ian to bedi r2. 1912. oe +. Kies, 9 esache | einer Moh: _ Lab. Landwirt. Berlin 1: 76-83. 1865. 8. bese amg ROSENBAUM, ne Sponospora -. homa tuberosa on n the Irish potato. Jour. Agric. R ior : 9. Neces, F. Wo Uber Ureduciy Abalebs _ reaceen. lean Centralbl. ec oe 1914. 284 BOTANICAL GAZETTE [OCTOBER in the development of bulbils were drawn with the same magnification, using 4 mm. objective and no. 12 eyepiece. The text figures are microphotographs taken by W. J. WESTERBERG. The plates have all been reduced in repro- duction about three-fourths. Fics. 1-16.—Papulospora pallidula. Fic. 1.—Hypha showing large oil globules. Fics. 2-6.—Dichotomously dividing primordium Fics. 7, 8.—Primordia more or less irregular in hess dichotomous branch- Fic. 9.—Further development of bulbil. Fics. ro-12.—-Second mode of forming a bulbil. Fic. 13.—Mature bulbil germinating. Fic. 14.—Cells of an old t bulbil loosely adhering to each other; some of cells germinating. Fics. 15, 16.—Terminal primordia. Fics. 17-24.—Papulospora byssina. ing Fic. 24.—Primordia of at least 3 bulbils ad same filament at a, b, and ¢ ern s 25-38.—Papulospora aurantiaca. : Pros. 25-32- —Variations in mode of coiling of primordium of bulbil. Fics. 33-38. of bulbil. : Fic. 39.—Germinating bulbil of Populespora magnificus. _ Fics. 40-47.—Papulospora nigr : Fie. 40-—Portion of hypha showing large il globules and clamp comme i ee ny Sige, inthe macy Serenata ee Np : he ichsec oo of oe with haces pie cells ——* fled PLATE XX] BOTANICAL GAZETTE, LXIV HOTSON on BULBIFEROUS FUNGI _ BOTANICAL GAZETTE, LXIV PLATE XXII BOTANICAL GAZETTE, LXIV PLATE XXIII eee é ss iiweSSs i fy. Ry | CRYOSCOPIC DETERMINATIONS ON TISSUE FLUIDS OF PLANTS OF JAMAICAN COASTAL DESERTS! J. ARTHUR HARRIS AND JOHN V. LAWRENCE Introduction PURPOSE OF STUDY.—In a memoir recently published? we have discussed in detail the reasons for considering the physico-chemical properties of vegetable saps a subject of real importance in ecology . and phytogeography, and have reinforced the arguments advanced by series of determinations showing distinct differences in the osmotic pressure, or osmotic concentration, as some prefer to call it, of leaf sap from plants growing in different local habitats in the Arizona deserts. A comparison of these determinations with a series made in the more mesophytic region of the Station for Experimental Evolution? demonstrated a conspicuous differentia- tion of the Tucson and Cold Spring Harbor regions with respect to the osmotic concentration of the tissue fluids of the constituent species. In view of the s diff tablished between these two floras, it seemed desivable to select a forested region of as uniformly distributed and as nearly maximum rainfall as possible — for comparison with the areas already studied. Thus we hoped to 3 the iohtaha tals force ol the asad of Tenis wey de | by Sureve,* seemed the most suitable locality. ‘We therefore spent a period of several uring t eae ree 286 BOTANICAL GAZETTE [OCTOBER of 1915 in a study of the osmotic concentration of the tissue fluids of the plants of the montane region. The results of this study will be published later. Fortunately, while in Jamaica we were also able to visit the remarkable coastal deserts of the southern shore. It seemed to us highly desirable to secure as large a series of determinations as possible upon the species constituting their flora for comparison with the observations already made in the Arizona deserts in the neighborhood of the Desert Laboratory. Our purpose in this paper, therefore, is to present a considerable series of novel physiological data on the plants of the desert area of the southern coast of Jamaica; to compare the flora in this regard with that of the southern Arizona deserts and of some other locali- ties; and to hazard some — concerning biological factors — immediately underlying certain of the differences observed in various species of the coastal region. _ CHARACTERISTICS OF DESERTS INVESTIGATED.—Lying as it does — in the center of the Carribean Sea, the island of Jamaica intercepts the trade winds in a way to cause a pronounced differentiation in its climatic conditions. This is especially true on the narrow 2 S eastern end, where the Blue Mountains, attaining a height of nearly = 7500 feet, separate two narrow coast plains. At Port Antonio, at _ Sea level on the northern coast of the island, the mean annual ae -.con, at sea level oe = ‘ on the southern coast of the island, precipitation is on the average - : | ae less. than 38 inches per year. Temperature and insolation char acteristic of sea level at 18° N. latitude coupled with local peculiari- ties of the substratum have here resulted in & conspicuously ne rainfall averages more than 130 inches. At : _—_-xerophytic type of vegetation. sy the island from the mouth of the Cane River, just east of | oe for a distance of about 7o miles to the Pedro Bluffs. Its greatest oe _ As limited by SHREVES, the desert deers the southern oo of : Z SF ac is = in the Healthshire Hills, in the vi icir mad of ee 1917] HARRIS & LAWRENCE—TISSUE FLUIDS 287 Pen. The desert is confined to the limestone areas which have an extremely rough surface, with layers or shallow pockets of soil which are not capable of retaining moisture or of deriving it by capillarity, and to the finely ground substratum of the coastal flats. The proximity of the sea and other factors maintain a high relative humidity. Atmometer readings by SHREVE indicate that . the evaporation rates here and at Hope Gardens, which is some 6 miles inland and behind a low ridge of hills, are not very different. All of our collections were made in the immediate vicinity of Port Henderson, a point easily accessible from Spanish Town, where it was possible to carry out the laboratory phases of the work, and which afforded access to both the rocky limestone hills and the coastal flats. Because of military restrictions, made with great courtesy, we were unable to visit all parts of the region. Probably distribution of the collections over a wider area would have modified but little the cache here drawn, anne it _—— have in- creased the number of species upon which de are based. The area considered comprises open beach, a mangrove swamp, a highly saline tract of mud flats practically free of vegetation, somewhat higher-lying flats of finely ground detrital material, and rocky limestone hills, the soil = which i is relatively ane om retaining water. = The determinations hick we we made on the plants of the om each and on those of the a grove swamp resel ae for a lis u : . : : pep eEse ties of strand and mangrove swamp species, = to be published laer " data a. other habitats (many of - rhich have already been collected) are ready. The vegetation of ie ee , rpalaigcd — aud flats is practically limited to the two well aS , of = . eet ie former i is much the more ‘common, and the two ‘man- Se : : Avicennia nitida and —e racemosa, which occur 288 BOTANICAL GAZETTE [OCTOBER species, or upon cacti. Here, as is generally the case in desert regions, the classification of the plants with respect to growth form presents considerable difficulty. Trees are shrublike in stat- ure and shrubs are correspondingly reduced in size. In spots where the soil is deeper or more retentive of moisture the size of the individuals may be much greater. Describing the vegetation in terms of the species upon which we were able to secure determinations, we may note that the vegeta- tion of the coastal flats is made up chiefly of a mesquite tree Prosopis juliflora, and a columnar cactus Lemairocereus Hystrix. Other trees or shrubs are Caesalpinia vesicaria, Capparis cynophallophora, C. ferruginea, and Guaiacum officinale. Our lists show determina- tions for 7 species of cacti. In addition to these, Sesuvium Portu- lacastrum, Batis maritima, and in places Bromelia Pinguin are abundant. On the rocky hillsides the more truly arborescent forms are Bauhinia divaricata, Caesalpinia vesicaria, Canella Winterana, Capparis ferruginea, Cassia emarginata, Ichthyomethia Piscipula, Melicocca bijuga, Prosopis juliflora, Sarcomphalus Sarcomphalus, Schoepfia chrysophylloides, and Tamarindus indica. The shrubs are Chiococca alba, Croton flavens, Hypelate trifoliata, Lantana crocea (?), Morinda Roioc, Solanum bahamense, and Turnera ulmifolia. The smaller ligneous species are the dwarf shrubs or half shrubs Achyranthes halimifolia, Lantana reticulata, and Jatropha gossyp- folia, and the twiners Echites Echites and Phillivertella clausa. The only monocotyledonous plant from which a determination was secured was Bromelia Pinguin. The only herbaceous succulent noted was Bryophylium pinnatum. The cacti may also occur on the rocky hills, but in the immediate vicinity of Port Henderson the flora is almost exclusively of small trees and shrubs. There are but few species in our series of determinations éeencains to the two habitats. These are Achyranthes halimifolia, C aesalpinia vesicaria, Capparis ferruginea, Jatropha gossypifolia, a and Prosopts julifiora. MeEtHops.—The very simple technique used in making the determinations has been described in detail elsewhere. Samples ® Gortner, R. A., and Harris, J. ARTHUR, Notes on the technique of cout the depression of the tenting point. Plant World 17:49-53. 1914- 1917] HARRIS & LAWRENCE—TISSUE FLUIDS 289 of tissue were collected in test tubes of about 100 cc. capacity and taken to the laboratory for freezing by immersion for several hours in an ice and salt mixture, in order to avoid errors in the extraction of sap as noted by Drxon and Arxins’ and ourselves.’ The sap was then extracted by pressure in a small heavily tinned press bowl with a powerful hand screw. After filtering, the freezing-point lowering of the sap was determined by the use of a thermometer graduated in hundredths of degrees with divisions sufficiently large to permit reading approximately to thousandths of degrees. In some instances a cloudiness or flocculent precipitate similar to that described by GorKE? was observed when the sap approached the freezing point or passed it in undercooling. We had no facilities for any investigation of these substances, but believe their pressure does not greatly, if at all, influence our results. The measurements are recorded in degrees depression (A) corrected for undercooling and in atmospheres pressure (P) from a table published elsewhere.” The fact that a number of the deter- minations exceeded the range of the table as originally printed has led to the publication of a supplementary one." Presentation and analysis of data In the following protocol the values to the extreme right opposite the species names are (whenever possible) averages. These averages are designated by bars. The individual readings upon which they are based, with their dates of collection,are entered below the species, except in the cases in which only a single determination is available and must serve, instead of an average, to represent the species. 7 Drxon, H. H., and Arxins, W. R. G., Osmotic pressures in plants. I. Methods of extracting sap from ont ores Sci. Proc. Roy. Dublin Soc. N.S. 13:422-433. 1913; alsoi h. Trin. Coll. Dublin 2:154-172. 1913- § Gortner, R. A. piiceen i V., and Harris, J. ArtHUR, The extraction of sap from ae tissues by pressure. B iochem . Bull. 5:139-142. pl. I. 1916. ° Gorxe, H., Uber chemische Voeskhee beim Erfrieren der Pflanzen. Land- seas Wecual Stat. 65:149-160. 1906. * Harris, J. ARTHUR, and GorTNER, R. A., Note on the apc of oa — reprinted in Matrnew’s Physiological Chemistry. ™ Harris, J. ARTHUR, An extension to 5. 6s ot tables to determine the osmotic Pressure of exp: of the freezing point. Amer. Jour. Bot. 2: 2418-419. 191s. 290 BOTANICAL GAZETTE [OCTOBER A. THE COASTAL FLATS The following determinations were made on the sap extracted from the leaves of the small more or less sclerophyllous trees. en WOUICI I Bi ee ia in coche cos ina ees A=2.95, P=35.4 January 25, A=2.91, P=34.9 March 26, A=3.08, co. ° March 30, A=2. 87, P =3 Capparis cynophallophora L. c pid OPED, tect A=3.76, P=45.0 January 30, A=3.87, P=46.4 COPOOrts TUTRNINEE Bie Se a i es A=4.12, P=49.3 January 25, A=4.10, P=49.1 March 30, A=4.13, P=49.4 se fee CAG HIE a ee cd ices ta teins A=4.35, P=52.1 January 25, A=4.48, P=53.6 March 26, A=4.22, P=50.5 30, A=2.42, P=29.1 April 2, A=2.63, P=31.5 Three species which may be classified as dwarf shrubs or half shrubs gave Achyranthes halimifolta Lam. : 2.0... oe ee ee i ee i ok A=2.86, P=34.3 anuary 22, A=3.23, P=38.7 January 25, A=2.48, P=29.8 — = SOeree WI Te ek ei ek A=4.18, P=50.0 January 22, A=4.18, P=50.0 January 25, A=3.84, P=46.0 March 26, A=4.58, P=54.8 March 30, A=4.12, P=49.3 a8 ae OM ODIE MULIIOITONG Doi es a a =1.17,P=14.1 January 25, A=1.24, P=14.9 January 30, A=1.10, P=13.2 Our visit was not made during the time of the development of ephemeral plants. The only herbaceous form which we secured was the well known halophyte Sesuvium.. | A=2.86, P=34-3 he ee ee ee March 30, A=2.11, P=25.4 April 2; A=1.63, '=19.5 1917] HARRIS & LAWRENCE—TISSUE FLUIDS 291 A portion of the foregoing species are sclerophyllous and a portion are succulent-leaved plants. The tissues of the Cactaceae, which are the dominant forms on the coastal flats, yield fluids giving the following values: Cactus Melocactus L. anuary 22, for cortex, A=o.40, P=4.9 for pith, A=o0.49, P=5.9 March 30, A=o0.46, P=5.5 April 2, Cephalocereus Swartzii (Griseb.) Britton and Rese March 30, for cortex, A=o.59, P=7.1 for pith, A=o.70, P=8.5 April 2, - cortex, A=o.59, P=7.1 ith, A=o0.69, P=8.3 an gracilis (Mill. Britton March 26, for cortex, A=o.53, P=6. Hylocereus triangularis (Mill.) Britton and Rose January 25, A=o0.48, P= Lemairocereus Hystrix (Solm Byck) Britton and Rose f or cortex, A=o0.64, P= for pith, A=0.75, P=9.0 January 25, for cortex, A=o.44, P=5.2 for pith, A=0.64, P=7.7 A=0.64, P=7.6 March 30, for cortex, A=o.53, P=6.3 for pith, A=o0.57, P=6.9 April 2, for cortex, A=o.80, P=9.7 for pith, A=o0.76, P=9.1 March 26, Opuntia Dillenii (Ker Gawl.) Haw. January 25, A=o.57, P=6.8 March 30, A=o.75, P=9.0 April 2, A=o.69, P=8.3 Opuntia spinosissima Mill. 6.8 March 26, A=o.78, P= 9.4 8.6 I April 2, A=o.93, P=11. The only monocotyledonous plant studied was the terrestrial Bromelia, which may be included here Bromelia Pinguin L eee eee ee eee www ee eee ee March 26, A=0.63, P=7.6 292 BOTANICAL GAZETTE [OCTOBER B. THE ROCKY HILLS The classification of the plants from the rocky hills into trees, shrubs, and other growth forms has been indicated in the foregoing introductory section. Here, therefore, we merely give the results of the determinations in alphabetical order. , — oe BR he ce ess. da eek A=2.83, P=33-9 Mar 26, A=3.16, P=37.9 March 30, A=2.49, P=29.9 Bauhinia divaricata L January 27, A=3.10, P=37.2 January 30, A=2.98, P=35.8 as oe ees PU a a ee Se A=0.58, P= 7.0 anh 7 joes pinnatum (Lam.) Kurz. oda cecssuw es eOg4, FO 5-5 March 26, A=o.49, P= 5.9 March 30, A=o0.37, P= 4.5 April 2, A=o.50, P= 6.0 Caesalpinia vesicaria L...........0.5..0-.-. January 27, A=2.26, P=27.2 ] A Capparis tavrepiahe oe ee ie Se A=3.58, P=42.9 January 30, A=3.50, P=41.9 March 26, A=3.66, P=43.8 mn Cassia emarpdie Ti ee oe ss A=1.97, P=23-6 January 27, A=1.99, P=23.9 anuary 30, A=1.94, P=23.3 Chiococca alba i pee a, January 25, A=3.64, P=43.6 Croton flavens L..... 2.2.2.2 eV a January 27, A=1.47, P=17-7 Echites Echites as Britton (Echites umbellata Jacq.) January 27, A=1.78, P=21-4 Hyfelale WE MIMG SW oo a aa ce A=2.34, P=28.1 Jan uary 30, A=2.30, P=27.6 Ichthyomethia Piscipula (L.) Hitch........... March 30, A=1.49, P=18.0 Jalrobha gossybiielia Lien cs January 30, A=1.02, P=12-3 ieee Tee ee rch 26, A=1.60, P=19-2 Lantana reticulata Pers... .....: 2... 03... January 27, A=2.14, P=25-7 Moldcwca RGN Lia es: A=1.87, P=22.4 anuary 30, A=1.73, P=20.8 March 30, A=1.73, P=20.8 April 2, A=2.14, P=25.7 1917] HARRIS & LAWRENCE—TISSUE FLUIDS 293 MIE Tlie Tigo tis rok ge an A=1.76, P=21.2 March 26, A=1.77, P=21.3 March 26, A=1.76, P=21.1 aT se ae 1.84, P=22.1 i 1.68, P=20.2 Philibertella oa: (Jaca, Ves ANE ee oe January 27, A=1.51, P=18.2 Evosopss juliflora (L.) D.C... . 5 osc, January 27, A=2.69, P=32.3 Sarcomphalus S vince (L.) (Sarcomphalus laurinus Griseb.) January 27, A=1.63, P=19.6 Schoepfia chrysophylloides (Rich.) Planch................. A=2.79, P=33.5 uary 27, A= , P=30.2 January 30, A=2.66, P=32.0 March 26, A=2.93, P=35.1 il 2, A=3.06, P=36.7 pein bokamonse Lo a, A=1.98, P=23.8 , A=2.09, P=25. We ‘ Tidbits oe Bi ee at re ee es A=1.75, P=21.0 Apri 2, “Whee Geena th. 2 January 25, A=3.39, P=40.7 Analysis of data In the analysis of these data the first step is to put on one side the two species with more or less succulent leaves, Bromelia Pinguin and Bryophyllum pinnatum, and the cacti. These show low con- centrations of about 6-9 atmospheres. They are not at all com- parable with the other forms investigated in these deserts and elsewhere and will be discussed separately on a subsequent page. Of the thin-leaved forms, Jatropha gossypifolia has a thickened, almost succulent stem. It is a form much more characteristic of the coastal flats than of the rocky hillsides. The rather tender leaves yield a sap of lower concentration than that of any other thin- leaved species. 204 BOTANICAL GAZETTE [OCTOBER AVERAGE CONCENTRATION IN COASTAL DESERTS.—As a pre- liminary to any further analysis of these data the average values for the two habitats and the different growth forms must be obtained. For the 5 arborescent species of the coastal flats the general average is given by Caesalpinia A=2.95, P=35.4 Capparis A=3.76, P=45.0 Capparis A=4.12, P=49.3 Guaiacum A=4.35, P=52.1 Prosopis A=2.53, P=30.3 General average 3.542 42.42 The 3 species of the coastal flats which have been classified as dwarf shrubs differ greatly in concentration. Achyranthes is a rather hard-leaved halophyte which does not penetrate to the most saline spots. It is characterized by a concentration of about 34 atmospheres as compared with about 50 atmospheres in the highly succulent Batis maritima, the sole species found in the more saline spots. Sesuvium Portulacastrum is characteristic of only the less saline portions of the flats, and shows a far lower average concentra- tion, although some of the individual values attain about the average for Batis. The actual averages are: mean depression, 2.737°; mean con- centration, 32.80 atmospheres. For the more truly arborescent species of the rocky slopes the values are: - Bauhinia A=3.04, P=36.5 Caesalpinia A=2.26,'P=27.2 Canella A=3 18, P=38.1 shen A=3.58, P=42.9 sia A=1.97, P=23.6 Sean A=1.49, P=18.0 Melicocca A=1.87, P=22.4 Prosopis A=2 69, P=32 3 Sarcomphalus A=1 63, P= 19 6 Schoepha A=2.79, P=33.5 Tamarindus A=1.75, P=21.0 | General average 2.388 28.6 1917] HARRIS & LAWRENCE—TISSUE FLUIDS 295 The general average for the shrubs, half shrubs, and woody twiners of the rocky slopes is given by Achyranthes A=2.83, P=33.9 Chiococca A=3.64, P=43.6 Croton A=1.47, P=17.7 Echites A=1.78, P=21.4 Hypelate A=2.34, P=28.1 Jatropha A=1.02, P=12.3 Lantana A=1.60, P=19.2 Lantana A=2.14, P=25.7 Morinda A=1.76, P=21.2 Philibertella A=1.51, P=18.2 Solanum A=1.098, P=23.8 Turnera A=3.39, P=40.7 2.192 25.48 General average Thus the concentrations determined for the smaller forms are practically as large as those for the more truly arborescent species. Combining all the ligneous perennials of the rocky slopes (that is, omitting from the whole series of determinations only Bromelia and Bryophyllum), we have for the general average of the species means or species constants: mean depression, 2.249°; mean concentra- tion, 27.000 atmospheres. Combining both arborescent and suffrutescent growth forms, excepting only the herbaceous Sesuvium Portulacastrum, Bromelia, Bryophyllum, and the cacti, the values for the 31 species means or constants of the two habitats recognized give the following averages: mean depression, 2.505°; mean concentration, 30.05 atmospheres. By including the herbaceous perennial Sesuvium, the averages for 32 species means or determinations is changed to A=2.516, P=30. 18. COMPARISON OF CONSTANTS WITH THOSE FOR MESOPHYTIC REGIONS.—The first question to be answered in the analysis of these data is that concerning the relative values of osmotic concentration in the sap of desert and mesophytic plant organisms. Specifically, do the results of this study confirm those obtained by Frrrmnc” in “ Firtinc, H., Die Wasserversorgung und die osmotischen Druckverhiltnisse der Wiistenpflanzen. Zeitschr. Bot. 3:209-275- 1911. 296 BOTANICAL GAZETTE [ocroBER his plasmolytic studies of the plants of North African deserts and by ourselves in our cryoscopic determinations in the Arizona desert region? With an affirmative answer to this question, a second one concerning the closeness of agreement between the two desert areas so far investigated is open to discussion. Comparisons of the constants for sap properties here secured with those for other regions must be drawn with care and in only a preliminary fashion. This is quite obvious because of the many factors which may influence the constants, but concerning which little or no quantitative data are at present available. For example, the determinations for the Arizona deserts are based on collections made during the period of spring vegetative activity following the winter and spring rains; those for the coastal deserts were made during the dry winter season. The collections made on Long Island and in St. Louis at the Missouri Botanical Garden comprise decidu- ous species whose leaves must have developed during the spring of the same year. The age of the leaves of the desert plants is often quite indeterminable. Bearing these limitations in mind and remembering that there are probably many others, we note first of all that in a general way the flora of the Port Henderson deserts is in excellent agreement with that of the Tucson region in showing a high concentration of the tissue fluids of its constituent species. The exceptions only emphasize the rule. us comparing the Port Henderson averages for ligneous perennials with those tentatively drawn from unpublished data for trees and shrubs for the Cold Spring Harbor region," we fin Cold Spring Harbor, 14.40 atmospheres Jamaican coastal desert Coastal flats only, 38.81 atmospheres Rocky slopes only, 27.00 atmospheres Flats and rocky slopes, 30.05 atmospheres. B The averages given for both at _ ee Harbor and the Tucson series are by GortNer, LAWRENCE, and Harris. They will he replaced shortly by representing not merely determinations made in 1914 but far more extensive work ty abe ee and Harris in rgrs and subsequent work by Harris. The field work has ne for a summer series from the Arizona deserts, but the data cannot be com- prorat worked up for some months. ‘ 1917] HARRIS & LAWRENCE—TISSUE FLUIDS 207 It is idle to go further into these comparisons. It is clear that the ligneous plants of the Jamaican coastal desert, those of the rocky hills as well as of the more or less saline flats, are character- ized by concentration of tissue fluids about twice as great as those of the Cold Spring Harbor region. The extensive series of species studied by OHLWEILER™ suffer from the disadvantage (in relation to the present paper) of being assembled from their natural habitats and grown in a Botanical Garden. All, however, are forms capable of growth in the open at St. Louis. These show a range of from about 7 to about 24 atmos- Pheres. The average value of the 90 determinations is 14.96 atmospheres. Thus, OHLWEILER’s St. Louis series agrees very closely with our own preliminary average for Long Island habitats. Here again the values are only about half as high as those deter- mined in the coastal deserts. COMPARISON OF CONSTANTS WITH THOSE FOR TUCSON REGION.— Turning to averages for a comparison of the concentration of the Sap of the Jamaican coastal and the Arizona desert floras, the results for ligneous perennials only are: Arizona series, 24.97 atmospheres; Jamaican series, 30.05 atmospheres. Apparently concentration is somewhat greater in the Jamaican series. If the comparison between the two desert areas is to be drawn on a more analytical basis, it may be noted that the values determined for the trees of the coastal flats are of the same order of magnitude as those derived from the species of Atriplex examined in the Arizona salt Spots. For example: Atriplex canescens P=39.5 Atriplex canescens P= 67.5 Atriplex canescens angustifolia P=32.8 Atriplex polycarpa P=52.0 In the Jamaican coastal deserts the trees and shrubs from the rocky slopes show concentrations lower than those of the coastal flats. In the Arizona deserts the plants of the rocky slopes show far lower osmotic concentrations than do those of the salt spots. _ Comparing Arizona and Jamaican rocky slopes the results are: *4 OHLWEILER, W. W., The relation between the density of cell saps and the Senne pemet ot of ‘ict: Ann. Rept. Mo. Bot. Gard. 23:101-131. pl. 6. 1912. 298 BOTANICAL GAZETTE [OCTOBER Port Henderson region, 27.00 atmospheres; Tucson region, 22.01 atmospheres. With the exception of the salt spots, the bajada slopes of the Tucson region show the highest concentration. Comparing with the rocky slopes of the coastal region, the results are: Port Hender- son rocky slopes, 27.00 atmospheres; Tucson region, bajada, 30.34 atmospheres. Because of seasonal differences it is undesirable to attempt to analyze too closely the differences between the two desert areas. Such could be done if determinations upon the coastal deserts immediately subsequent to a rainy season were available. Until such data.are at hand and until our determinations for the summer flora of the Arizona deserts are ready for publication, it is premature to discuss the matter further than to say that both of these regions show concentrations far higher than do those of mesophytic habitats, and that they are in good general agreement between themselves. OsMOTIC CONCENTRATION IN THE CACcTI.—From the floristic standpoint the most striking feature of these coastal deserts is the remarkable growth of arborescent cacti in immediate proximity to dense mangrove swamps. From the physiological standpoint the most remarkable result of these studies is the demonstration that the fluids of these cacti have about the same concentration as those of other desert regions. . The 28 determinations made on the sap of the 7 species belonging to the 6 genera of cacti show a range of A=o.40 to A=o.93, or P=4.9 to P=11.1, with an average for the series of A=o.626 and P=7.52. Yet these cacti are growing in the same substratum as sclerophyllous arborescent species with an average concentration for the species of A=3.54 and P=42.4. Much of the cactus-covered area has a dense undergrowth of Batis maritima, which has an average of A=4.18, P=s0.0. Sesuvium, which sometimes occurs but is not so abundant as Batis among the cacti, has sap averaging A=2.60, P= =31.2. Better illustrations of the diverse reaction of two organisms to the same general environ- mental situation could hardly be found. These results are in close agreement with the findings of those who have worked on cacti in other regions. 1917] HARRIS & LAWRENCE—TISSUE FLUIDS 299 As early as 1905 CAvARA’ investigated a series of cacti by the freezing-point lowering method and gave values not very dissimilar from our own. Sap was extracted from untreated tissue. This may result in abnormally low values of the measures of osmotic concentration. MacDovueat and Cannon” have estimated the following con- centrations in atmospheres for sap of cacti at 25°C: Carnegiea gigantea, 6.78; Echinocactus Wislizenii, 5.72; Opuntia Blakeana, 8.88 and O. versicolor, 11.98. It is interesting from the historical standpoint to note that cacti, which with certain other succulents are quite anomalous among desert plants, were perhaps the first to be considered in relation to the problem of the dependence of absorption of water by desert plants upon higher osmotic pressure of their sap. Thus Livinc- STON” concluded, from determinations by the freezing-point, boiling-point, and tissue curvature methods, that the saps of Cereus, Echinocactus, and Opuntia “exhibit osmotic pressures no higher than those commonly found in plants of the humid regions. For these cacti at least, therefore, adaptation to desert conditions is not mani- fest in increased concentration of the cell sap.” From the foregoing account we may say that the cacti of the Jamaica coast exhibit sap concentration of roughly the same order of magnitude as do those of other regions. Possibly they are somewhat higher than those of purely non-saline localities, but until series in which standard methods ofsap extraction have been’ employed are available from other habitats this cannot be asserted tobe the case. Certainly the cacti, with Bromelia and Bryophyllum, are conspicuous exceptions to the general rule of high osmotic con- centration in these coastal forms. ‘To this point we shall recur later. Results In the foregoing paragraphs we have shown that the sap of the plant species of the Jamaican coastal deserts has an osmotic ** Cavara, F., Risultati di una serie di ricerche crioscopiche sui vegetati. Cont. Biol. Veg. R. Ist. Bot. ice 41-80. 1905. * MacDoueat, D. T., and Cannon, W. A., The conditions of parasitism in plants. Publ. Carnegie Ins Inst. Wash. 129. IgI0. _ ™Livineston, B. E., The relation of desert plants to soil moisture and evapora- tion. Publ. Carnegie Inst. Wash. 50. 1906. 300 BOTANICAL GAZETTE [ocTOBER concentration far higher than those of mesophytic regions, and quite equal to if not slightly higher than those of the winter vegetation of the Arizona deserts. While determinations based on these species growing in other environments are as yet too few to justify detailed discussion, it seems most probable that the properties of their sap are due in part to the local conditions and not merely to the existence here of a. series of species characterized by high concentration.® In the few cases in which constants for a species were obtained — from the coastal flats and from the rocky slopes, the values from the slopes are generally lower than those from the flats. Thus the single determination on Caesalpinia vesicaria from the slopes gives 27.2 atmospheres as compared with 34.4, 34.9, and 37.0 from the flats. Capparis ferruginea from the slopes gives 41.9 and 43.8 atmospheres as compared with 49.1 and 49.4 atmospheres when growing on the flats. Jatropha gossypifolia gives 12.3 atmospheres on the slopes as compared with 13.2 and 14.9 on the flats. In the case of Prosopis juliflora and Achyranthes halimifolia, the result is uncertain. The two collections of Achyranthes from the slope gave 29.9 and 37.9 as compared with 29.8 and 38.7 atmos- pheres for the flats. Prosopis on the slopes yielded sap with a concentration of 32.3 atmospheres as compared with two readings of 29.1 and 31.5 from the flats. To what extent the osmotic concentration of the sap of the sclerophyllous forms is influenced by the actual presence of salt in the leaves can only be determined by special methods. The leaves of some of the forms growing on the coastal flats, for example Capparis ferruginea, are perceptibly salty to the taste; others are not. It can hardly be doubted that the enormous variation in the concentration of the leaf fluids of such forms as Batis maritima and Sesuvium Portulacastrum, the leaves of which are practically re- inforced water bags, is due primarily to electrolytes absorbed from the soil. The fact that the various cacti are here characterized by sap of low concentration, as when growing in true desert environ- 8 . * ‘3 . ve onl A collection of the leaves of Guaiacum offcinale from Spanish Town ga ; A=2.66, P=31.9 as compared with two constants each over 4° (50 a in the coastal flats. 1917] HARRIS & LAWRENCE—TISSUE FLUIDS 301 ments, indicates that the absorption of any considerable quantity of salts and their retention in solution is not a-necessary result of existence in a saline substratum. Some physiologists have sug- gested that the high osmotic concentration of the fluids of desert plants is due primarily and directly to greater quantities of soluble material in the substratum than generally occurs in regions of higher rainfall. The validity of the conclusion is rendered highly improb- able by the high concentrations demonstrated for the plants of the rocky hillsides. While in general it is better to reserve hypotheses concerning the peculiarities of individual species until theoretical discussions of their relation to environmental factors can be replaced by inductions from actual quantitative data secured in the particular habitat under investigation, it may be useful to other workers, especially in the case of a problem requiring so many different kinds of specialized observation in a habitat not easily accessible to most botanists, to point out certain possible interpretations of the observed phenomena. The question of greatest interest is that ing the difference in behavior of the several species of the same habitat, say the Coastal flats. For example, the leaves of Prosopis and Caesalpinia yield sap of a distinctly lower concentration than do those of Guaiacum and the two species of Capparis. Jatropha gossypifolia has sap of only about one-fourth of the concentration of that of Batis maritima, with which it is so generally associated. The cacti and the terrestrial bromeliad exhibit only a fraction of the freezing- Point lowering shown by the hard and succulent leaves of the arborescent and suffrutescent species among which they are interspersed. Any suggestion in interpretation of these phenomena must be purely tentative and be substantiated by, or discarded on the basis of, actual field studies. Those which are here called to the attention of ecologists are not at all speculative, but merely the result of an attempt to correlate the results of studies by a number of specialists in the various fields of desert botany. _ Sesuvium Portulacastrumand Batis maritima are both species with highly succulent leaves. In both, the high osmotic concentration 302 BOTANICAL GAZETTE [OCTOBER of the leaf sap must be due primarily to electrolytes absorbed directly from the substratum. The difference between them, in so far as facts are available, seems to be an inherent physiological one. Sesuvium seems to be a form less tolerant of a highly con- centrated soil solution than Batis. The local distribution of the two, therefore, is not at all comparable, and the distinctly higher con- centration in the leaves of Batis is probably attributable to this fact. The only suggestion which can be made concerning the anoma- lous position of Prosopis among the small trees is that it has a more deeply penetrating root system which taps underflow water, poor in solutes, derived by seepage from the neighboring lime- stone hills.* From the extensive observations in the deserts of southern Arizona it is known that the related species Prosopis velutina is characterized by deep root penetration. Thus SPALD- Inc” and Cannon” both note the wide horizontal and the deep vertical distribution of the root system, which may reach a depth of 8m. or over. CANNON” concludes that with uniform and pene- trable substratum the species becomes a tree where the perennial ground water does not lie at a depth greater than 50 ft. Such differences as exist between the concentration in the leaves of Prosopis and those of Batis maritima may be accounted for on the grounds of a much higher concentration of salts in the superficial soil layers. It is interesting to note in this connection that Prosopis julifior a from the coastal deserts gives values of osmotic concentration 1n general agreement with P. velutina of the Arizona deserts. Thus two determinations made on young leaves in the spring of 1914” gave: Santa Catalina Mountains, A=2.08, P=25.0 Tucson Mountains, A=2.33, P=27.9 This suggestion. was originally made by SHREVE (loc. cit.) to account for the presence of Prosopis in association — Batis — and other halophytes. 2 SPALDING, V. M., Distributi ts of desert plants. Publ. Carnegie Inst. Wash. 113. 1 Cannon, W. A., The root habits of desert plants. Publ. Carnegie Inst. Wash. 131. IgII. = Cannon, W. A., Some relations between root characters, ground water, and species distribution. Science, N.S. 37:420-423. 1913. 3 Physiol. Researches 2:32. 1916. 1917] HARRIS & LAWRENCE—TISSUE FLUIDS _ 303 Hitherto unpublished determinations made in the summer of 1916 by LEamon and Harris give: Santa Catalina bajada Edge of arroyo, July 6, A=2.63, P=31.6 Same tree, August 14, A=2.40, P=28.8 Upper bajada, July 6, A=2.87, P=34.5 Mesa-like slopes, July 24, A=2.51, P*30.1 Surely no one will venture to assert on the basis of the available data that the Jamaican Prosopis juliflora and the southwestern P. velutina are sensibly different in osmotic concentration. With regard to the cacti, which have been shown elsewhere in this paper to have about the same concentration of tissue fluids as those found for this group growing in other habitats, the following points must be taken into account. The cacti are plants char- acterized by a deeply penetrating anchoring root system and a far- reaching superficially placed absorbing system. The evidences upon which this statement is based are chiefly those presented by Cannon in his large paper on the root habits of desert plants. If the coastal species agree in this regard with the forms which have been investigated, their absorbing organs are in contact with the actually dryest zone of the substratum during periods of severe drought, and with one physiologically dry, that is, characterized by a soil solution of high osmotic concentration, during periods of moderately abundant soil moisture. Such are the conditions which result in the high concentration found in Batis maritima, and one might, at first thought, suppose that the cacti would also be subject to the same conditions. Two additional factors, however, are to be taken into account: (1) the cacti are organisms capable of rapid storage of water during tran- sient periods of soil saturation, and its persistent retention during * The point is splendidly illustrated by two photographs of Opuntia published by CANNon (Amer. Nat. 40: cies fet: 2~3. 1906). MacDovcat and Spatpine (The water balance of succulent p Publ. Carnegie Inst. Wash. 141. 1910) have dealt with the problem in Sas aeart A number of other papers bearing more or less directly upon the general pro blem of water absorption and storage in the cacti have since appeared from the Desert Laboratory 304 BOTANICAL GAZETTE [OCTOBER long periods of deprivation; (2) the rainfall in the Jamaican coastal desert region is not distributed uniformly throughout the year. During periods of heavy rainfall the salts would be highly diluted or even largely washed out of the superficial soil layers in which the absorbing roots of the cacti lie, thus permitting water intake in quantities quite sufficient to maintain the plant until conditions again become favorable for water absorption. Thus species may differ very greatly in the relationship of their sap properties to environmental factors. Two species may be rooted in the same substratum, but because of differences in root penetration or in their capacity for water absorption or retention in reality they may be living in very different environments, or reacting quite differently to the same environment. Whether the hypotheses just advanced in explanation of the great diversity of the constants determined on the sap of particular species of plants growing in the same habitat be correct, can only be determined by intensive observational and experimental studies in the field. In the meantime they seem consistent with the available facts of desert plant physiology. Recapitulation In the present paper, which is one of a series on the physico- chemical properties of the tissue fluids of the plants of typical vegetations, we have presented the results of determinations of the freezing-point lowering of the tissue fluids of the plant species of the Jamaican coastal deserts; have compared the constants secured with those already available for the Arizona deserts and for meso- phytic habitats; and have offered tentative suggestions concern- ing the proximate causes of certain of the observed peculiarities of individual species. The deserts investigated constitute a small area on the southern coast of the island, where not merely the reduction in the rainfall due to the interception of the trade winds by relatively high moun- tains, but peculiarities of the substratum, contribute to the rigor of conditions limiting plant growth. Two sub-habitats have been recognized, low-lying coastal flats of finely ground detrital material, to a considerable extent impres- 917] HARRIS & LAWRENCE—TISSUE FLUIDS 305 nated with salts, and rocky limestone hills incapable of retaining moisture or of deriving it by capillarity. The vegetation of the coastal flats comprises a number of hard- leaved trees, among which is a mesquite very similar to that of the deserts of the southwestern United States, some thin and some succulent-leaved halophytes, and a number of genera and species of cacti which form a luxuriant-stand. The vegetation of the rocky "hills is of a more arborescent type, consisting chiefly of dwarfed broad-leaved trees with a number of small dwarf or half shrubs which have few purely structural characteristics which would ally them to desert plants. Taken as a whole, the species of the Jamaican coastal deserts show a concentration of their tissue fluids quite as high as, if not slightly higher than, that of as nearly as possible comparable growth forms in the Arizona deserts. The concentration of the leaf sap of the ligneous forms averages about two or three times that demonstrated in mesophytic regions. ile the plants of the rocky slopes show high concentrations, higher indeed than do those of the rocky slopes of the Arizona deserts, their constants are distinctly lower than those of the species of the coastal flats. The sap of the cacti has only a fraction of the osmotic concen- tration of that of the hard or succulent leaves of the trees and half shrubs among which they are rooted. The succulent Bryophyllum pinnatum and the terrestrial bromeliad Bromelia Pinguin show far lower concentrations than do the other species. Furthermore, Prosopis juliflora exhibits sap concentrations distinctly lower than those of certain other of the arborescent species. These form the extreme illustration of the fact that species of the same habitat show marked differences in sap properties. Suggestions concerning the underlying causes of such differences are offered. STATION FoR EXPERIMENTAL EVOLUTION Cotp Sprinc Harzor, Lone Istanp, N.Y. A NEW METHOD OF STUDYING PERMEABILITY Ss. C. Broexs (WITH TWO FIGURES) The writer™ has shown the desirability of a study of permeability by some method which should be entirely independent of other methods, and yield data the interpretation of which need not depend upon any unverifiable assumptions. A method is here presented which seems to fulfil these requirements. It has proved to be exceedingly reliable; and the experiments point clearly to the errors previously made in the interpretation of the data secured by many methods, and to the validity of the conclusions based on the evidence of certain others. Method The method depends upon diffusion of salts or other substances through a diaphragm of living tissue. For this purpose fronds of one of the common kelps of the New England coast, Laminaria Agardhii (formerly identified as L. saccharina), proved to be extremely satisfactory material because of absence of air spaces in the tissue, ease of manipulation, resistance to adverse conditions, and especially because it was possible to secure thin sheets of tissue in which there were no wounded surfaces in contact with the solu- tions. The method of experimentation was as follows. Sections of glass tubing of 18 mm. internal diameter were cut; one end of each piece was flared and the end ground flat. The resulting “cells” were either 2.5 cm. or 4 cm. in length, and were combined in pairs, each consisting of one long and one short cell (fig. 1, A, B)- The unground end of the longer cell was closed by a rubber tube and pinchcock (fig. 1, C, D). Disks were cut from the fronds of Lamt- naria of such a size as nearly to cover the ground ends of the tubes. Brooks, S. C., Methods of studying the permeability of protoplasm salts. Bor. GAz. 64:230-249. 1917. Botanical Gazette, vol. 64] [306 1917] BROOKS—PERMEABILITY 307 In the experiments with living material the surface of these disks was quickly dried with filter paper, the disks (fig. 1, Z) placed between the ground ends of a pair of cells, and the joint made tight with a stiff cement consisting of a mixture of vaseline and beeswax (fig. 1, F). Thus there were formed two cells separated by a dia- phragm of Laminaria tissue. The cell supplied with the rubber tube and pinchcock (hereafter called the “lower cell’’) was then filled with solution and the pinchcock closed, care being taken that no air bubbles were included in the cell. The apparatus was then inverted and the upper cell filled with solution, covered to check evaporation (fig. 1, G), and set in a suitable support. During these operations each disk was in contact with the air less than two minutes, which was not sufficient to cause any appreciable drying-out of the tissue. In order to obtain dead tissue for experi- ments on the permeability of the intercellular substance, living disks were exposed, after cut- ting, to an atmosphere saturated with chloro- form vapor at room temperature for 16-24 hours. They were next exposed to the air about one hour to allow the complete evapora- tion of any chloroform which remained in the tissue, and then placed in a large volume of sea oe water for about 24 hours to allow the establish- ment of equilibrium between the electrolytes of the sea water and those in the dead cells. At the end of this time the surface of the disks of tissue was dried with filter paper, and the apparatus set up as in the experiments with living material.. Tissue which had died a natural death gave results in every way similar to those given by tissue killed in this manner. The permeability of the tissue was shown by the rate of passage of salts through the diaphragm as shown by diminution of the difference of concentration between the solutions in the upper and lower cells. It is possible to measure rapidly, and with extreme accuracy, slight changes in the concentration of the solutions in either cell by determining the change in electrical conductivity. This method was therefore employed. 308 BOTANICAL GAZETTE [OCTOBER The solution used in the lower cells was either sea water or a pure salt solution of the same conductivity; while the upper cells contained a solution of half the concentration of that in the corre- sponding lower cell. Solutions of equal conductivity were used in order to facilitate comparison with the work of OSTERHOUT.’ Sources of error In order to obtain accurate data, the following precautions were taken: 1. The solutions were made up with distilled water, which had a specific conductivity of about 2X10-*® ohms. The sodium chloride used was Baker’s “analyzed”; the calcium chloride, Kahlbaum’s; and the lanthanum nitrate, Eimer and Amend’s “Tested Purity.” For this work an error of 1 per cent in the con- centration of the solutions was considered allowable. 2. In order to prevent dissolving of electrolytes from any part of the apparatus, the cells were made of Durox glass, and both cells and rubber thoroughly steamed immediately before each experiment. An apparatus of this type, set up with no Laminaria tissue, but with a thick layer of the vaseline-beeswax cement, and filled with distilled water, gave off only traces of electrolytes. The change in conductivity of the water in such a cell during 48 hours was equivalent to an increase of concentration of sodium chloride of less than 1X10-7M. Dissolving of electrolytes from the apparatus has therefore no significance in the experiments. 3. It was necessary to eliminate the influence of temperature. As it was impracticable to conduct the experiments at constant temperature, the cells were placed outdoors, the temperature vary- ing from —3° to +9° C. This amount of fluctuation produced no appreciable change in the rate at which salts passed through the tissue, and the low temperatures were exceedingly favorable to the maintenance of normal permeability.* ? Unpublished data of OstErRHouT show that differences of osmotic pressure the magnitude of those produced by the use of solutions of equal conductivity bare little effect on the permeability of Laminaria during the ape of time occu y these experiments. 3 Laminaria lives much longer when the temperature is low. While it may be en hy alive under laboratory conditions several weeks ‘at o° C., it perishes rapidly at 1917] BROOKS—PERMEABILITY 309 4. The Laminaria thallus is made up of masses of protoplasm (the cells) imbedded in a gelatinous intercellular substance. From this intercellular substance, in which the salts are present in the same concentration as in sea water, the salts will diffuse out intoa surrounding medium, and will alter its conductivity if it be other than that of sea water. From the protoplasm, also, a similar diffusion may take place, which for convenience may be designated as “exosmosis.”’ That there is actual passage of salts through the tissue was shown by the fact that the conductivity of the more dilute solution always increased, while that of the more concentrated solution decreased to a corresponding degree. There was no appreciable change in the volume of either solution even during experiments whose duration was greater than 24 hours. The relative amounts of increase in the upper cell and of decrease in the lower cell, as found in the experiments, were in fair agreement with those calcu- lated. If a given amount of salt passes from one salt solution to an equal volume of another solution having half the concentration of the first, the percentage of increase in the concentration of the latter will be double the percentage of decrease in the former. If there be a difference in volume between the two solutions, the change caused by the addition or removal of a given amount of salt will be inversely proportional to the volume. Thus, in one experiment the increase in concentration in the upper cell was I per cent per hour, while the decrease in the lower cell was 0.26 per cent per hour. Since the volume in the upper cell was 5.4 cc. as compared with 12.5 cc. in the lower, and the concentrations were as 1:2, the expected ratio between the changes in the two cells would serge SAP a4. 6; while the observed ratio was ao 3. 8. The premise was reasonably satisfactory, and it therefore could be assumed that changes in the concentration of the solutions in the upper cells would be nearly proportional to the amount of salt passing through the diaphragm. Two modifications of the method, however, were sufficient to eliminate entirely the errors due to both diffusion and exosmosis. The error due to diffusion of salts from the intercellular substance was eliminated by filling 310 - BOTANICAL GAZETTE [OCTOBER the cells, when first set up, with half-strength sea water in the upper cell and sea water in the lower. Thirty minutes was ample for the establishment of a steady diffusion gradient through the tissue between the two solutions. The upper solution was then replaced by fresh half-strength sea water, after which regular readings were taken. In order to eliminate the error due to exosmosis from the protoplasm, such as might be occasioned by toxic salts, 3 controls out of each set of 11 to 13 simultaneous experiments had the more dilute solution in both cells. At the end of the experiment the average conductance of the solution in the upper cells of the controls was taken as a standard of measurement, the average conductance of all the other upper solutions being divided by this figure in order to obtain the percentage which expresses their gain as compared with the control. The figures which were obtained in this manner measure the amount of salt which has passed through the tissue, while the errors due to exosmosis from the protoplasm as well as those due to diffusion from the intercellular substance are elimi- nated. 5. We must eliminate the error due to variations in the thick- ness and maturity of the disks of tissue from different fronds, and also that due to variations in the area of tissue through which salt can pass (such as might be introduced by unavoidable smearing of the cement over the surface of the disks).4 In order to eliminate all of these errors, controls were established in the following man- ner. After a preliminary half-hour with half sea water in the upper and sea water in the lower cell, the upper solution was replaced with 5.4 cc. of fresh half sea water, and the rate of change of conductivity determined at the end of 2 hours. Both upper and lower solutions were now replaced with solutions of the salt to be investigated (the fresh solutions having the same conductivity as those which they replaced), and the rate of change of conductivity determined after a further period of 2 hours. By dividing the 4 A single experiment was conducte d to determine the influence of frond thickness. The results were entirely negative. This is in accord with the results secured by ABEL (Aset, J. J., Rowntree, L. G., and Lurver, B. B., On the removal of diffusible substances from the circulating blood of living animals by dialysis. Jour. Pharm. and Exp. Ther. 5:275. 1914.), who found that onaeor at electrolytes through 4 collodion membrane was independent of the thickness of 1917] BROOKS—PERMEABILITY 311 figure obtained for the salt in question by that for the control period of the same disks of tissue, we obtain a figure (given in the ratio column of table II) from which all errors due to individual variations of the disks of tissue are eliminated. 6. The method for the determination of the conductance of the solutions was as follows. The solution was poured from the cell into a U tube of such dimensions as to give a conductance of the order of magnitude most accurately determinable, namely, about 1500-2000 ohmsX1077. The U tube was nearly immersed in a constantly stirred water bath whose temperature, determined to o%05 C., varied less than 0°8 C. in any one set of readings. A temperature correction of 2 per cent per degree Centigrade was applied to the actual readings to reduce them to the average tem- perature of the set, and the results calculated from the corrected readings thus obtained. A slide wire bridge, a standard 1000-ohm bifilar resistance (supplied with current from the secondary of a Nernst string inductorium at about 300-500 oscillations per second), and a telephone as the zero instrument were used in the customary manner to measure the resistance between bright platinum elec- trodes immersed in the solution at the opposite ends of the U tube. The distance between the electrodes was fixed. The readings had an error less than 0.1 per cent. The check experiments in half- strength sea water usually gave an agreement of corrected readings within 0.05 per cent. It will be seen that this degree of accuracy was ample for the purpose. Results It is desirable first to find out how fast the various salts pass through the intercellular substance, and whether there is any selective permeability due to any source other than the protoplasm. The data presented in table I show that the cell walls intercell substance of Laminaria are permeable to the salts used, and that the passage through the walls is nearly independent of the nature of the diffusing salt. In dead material the change of concentration is so rapid that owing to the decrease in the concentration gradient the rate of passage of salts through the tissue decreased, as is shown by the lower rate for the longer periods in both sea water and sodium 312 BOTANICAL GAZETTE [OCTOBER chloride. It is necessary, therefore, to draw our conclusions from the results of periods of equal length only. The relative permeabil- ity to different salts will then be represented by the following figures: calcium chloride 2.2, sea water 2.2, lanthanum nitrate 2.1, sodium chloride 2.1. | TABLE I PERMEABILITY OF DEAD TISSUE OF Laminaria : f con Solution in upper cell| Solution in lower cell | a _suctiviy . pers Half sea water...| Sea water...... ‘5 1.8 CaCh, 0.14 CaCl, 0.28 M. 4.5 2.2 lf sea water Sea water...... I2 ee ‘ Basra eewOumaeeee, Vee rs *.2 NaCl, 0.26 M...| NaCl, o. ot 5 2.0 alf sea water...| Sea water...... 12 1.2 La,Cl, 0.05 M..| La,Cle, o ae 4.5 2.1 NaCl, 0.26 M...| NaCl, 5 OE, 4.5 2.1 It appears probable that the slightly lower rate of diffusion of sodium chloride may have been due to a slight irreversible decrease in the permeability of the intercellular substance caused by the lanthanum nitrate, by which the tissue had been bathed imme- diately previous to the experiment with sodium chloride. This would be in accord with unpublished data secured by OSTERHOUT by determination of the conductivity of the tissue. The differences which might be expected to arise as an expres- sion of the diffusion coefficients of the salts are evidently of so small an order as to fail to influence appreciably the rate of diffusion through dead tissue. In view of the very imperfect state of our knowledge of diffusion coefficients, it would be unprofitable at the present time to attempt any further explanation of the influence of that factor in our experiments. It will be seen from the data given in table II that the presence of living protoplasm greatly decreases the permeability of the tissue as a whole. Living protoplasm offers, therefore, a very consider- able resistance to the passage of salts. That it is not normally (in sea water) impermeable to salts will appear from the following considerations. The permeability of the protoplasm for conven- 1917] BROOKS—PERMEABILITY 313 ience may be considered as the amount of salt passing through the tissue, expressed as the percentage of the amount passing through tissue bathed by sea water, as shown in the ratio column of table II. If the protoplasm be assumed to be wholly impermeable to salts of lanthanum, the figure 0.45, expressing the permeability of the tissue as a whole, would in this case represent diffusion through the intercellular substance only. Since this part of the tissue has been shown (cf. table I) to have no appreciable selective permeabil- ity, we may assume that not more than 0.45 of the permeability of the tissues to sea water, which is 1.07, is due to passage of salts TABLE II PERMEABILITY OF LIVING Laminaria First PERIOD SECOND PERIOD Ratio F) 2 3 Be U 3 Dura me Dura wees ae 5] - ~ poy PE seltica pc-aerdl ond ee 58 Upper solution|Lower solution “ago eg 3 Z z Z gm aeae geak! Sia butt OF i & 18..| Half se. a. 2:05 | 0.73 | Half sea Sea water | 2:00 | 0.78 | 1.07 water water water 19.. oi i 2:00 | 0.79 | NaCl, NaCl, 2:00 | 1.1m | 1.41 °0.26M °o.52M 22.. . x 2:06 | 0:73 | CaCl, CaCl,, 2:02 | 0.51 | 0.70 0.14 0.28 M 17a. « “ 1:35 | 0.73 | Las(NO,)s, | Las(NO,)s, | 1:35 | 0.33 | 0.45 0.05 M ‘o.10M through the intercellular substance. There remains 1.07—0.45= ©.62, which represents that part of the salt which passes through the protoplasm. In sea water, therefore, a minimum of on or 58 per cent of the salt, passes through the protoplasm, but the exact significance of this figure is doubtful owing to the arrangement of the protoplasmic masses in the tissue. In order to show the order of magnitude of the total diffusion through the living tissue, the results may be expressed in terms of the amount of salt in gm. molecules passing through 1 sq. cm. of tissue per hour. Ignoring the exceedingly slight change in molec- ular conductivity induced by such small changes of concentration, 314 BOTANICAL GAZETTE [ocTOBER the conductivity will be proportional to the concentration, and a change of 1 per cent in the conductivity of a 0.26 M solution may be assumed to indicate an increase of 0.0026 M in the concentra- tion. An increase of this size in 5.4 cc. of solution will necessitate the addition of 5 _— 5 Oo: 0026, or 0.0000140 gm. molecules of salt. If we divide oe pane chisel: | in this manner for the various salts, by the area of tissue in sq. cm. through which salts can pass, we obtain the figures given in table III. The figure for sea water was obtained by assuming all of its conductivity to be due to sodium chloride; but since sea water contains about 12 per cent of its electrolyte as salts of bivalent elements, which have a higher molecular conductivity than sodium salts, its actual molecular content is less than that of a sodium chloride solution having the same conductivity, and the figure given in table U1i is thus slightly too high. TABLE III GRAM MOLS DIFFUSING PER SQ. CM. PER HOUR THROUGH LIVING Laminaria Upper solution Lower solution po Se ng sea water..... MELO ee a ©.0000425 NaCl, o - = Wane ee o,53 Mo... 0.0000610 CaCl, ort Mc: CaCl, 0.28 M..:... ©.0000150 La (NOs, °. ee M..| La (NO,\«, 0.10M...| 0.0000034 The data of tables II and III also show that there is a selective permeability to the salts used. Sodium chloride is allowed to pass through the tissue most rapidly, the salts of sea water next, calcium chloride considerably less rapidly than sea water, and lanthanum nitrate least of all. That the effect is produced in large part by the kations, as was to be expected, is shown by the fact that preliminary experiments with lanthanum chloride (lacking the preliminary comparison period in sea water) showed a per- meability comparable with that to lanthanum nitrate. Thus in one experiment with lanthanum chloride the change of conduc- tivity of the upper solution was 0.30 per cent per hour, while that quoted for lanthanum nitrate is 0.33 per cent per hour. Whether 1917] BROOKS—PERMEABILITY 315 protoplasm is at all permeable to lanthanum salts cannot be decided with the data furnished by these experiments. It might be supposed that the protoplasm was normally more permeable to sodium chloride than to the other salts of sea water, and that therefore when bathed by pure sodium chloride solution more salt would pass through the diaphragm. On the assump- tion that the tissue is permeable only to the sodium and potassium chlorides, the molecules of which constitute 88 per cent of the molecules of salt in sea water, the rise in permeability on substitu- tion of sodium chloride solutions for sea water would be only that from 88 to 100. The observed rise is much greater, namely, from 76 to 100, and in addition it must be remembered that the calcium and magnesium salts of sea water are probably able to penetrate the tissue to some extent. Sodium chloride must increase the permeability of the tissue therefore. By analogy, it might be assumed that the permeability of the protoplasm decreased under the influence of calcium and lanthanum salts. In order to obtain more exact information in respect to this question, a set of experiments was conducted in which the per- meability was determined during successive periods of treatment with a given salt. The solutions in both the upper and lower cells were renewed at the beginning of each period. The results are shown in table IV and fig. 2. From these experiments it will be seen that the increase of permeability due to sodium chloride is progressive, and that it leads in the course of about 4 hours to a permeability of the tissues corresponding to that of dead material. The effect of calcium chloride, on the other hand, is to cause a temporary decrease in permeability, followed by a rise which at the end of about 12 hours leads to a permeability comparable with that for dead material. At the end of this time the material had assumed the green color characteristic of dead material. The experiment with sea water was conducted under conditions extremely unfavorable to the maintenance of normal permeability, the temperature rising to 14° C. during the third and fourth periods. Partial recovery is shown in the succeeding periods during which the temperature decreased. The last period was begun about 24 316 BOTANICAL GAZETTE [OCTOBER hours after the beginning of the experiment, and shows that the tissue, which had only partially recovered its normal permeability, TABLE IV PROGRESSIVE CHANGES IN PERMEABILITY OF TISSUE OF LIVING Laminaria; EXPRESSED RATE OF CHANGE OF CONDUCTIVITY OF SOLUTION IN UPPER CELL, IN PERCENTAGE PER HOUR bar gating enor ema UPPER SOLUTION, NACL, 0.26 M;|| Upper SOLUTION, CACIs, 0.14 M; SEA WATER : LOWER SOLUTION, NACL, 0.52 M || LOWER SOLUTION, CACL:, 0.28 M D Rate Dura- | Rate Dura- | Rate tion of |/Period begun at} _ tio of in min. ange in mi ee ch a Pi smc ictondces tm Sige change 6:45 A.M..| 120 | 0.67 || 2:40 P.M...,) 120] 1.21 || 9233 A.M....| 122 | 0-§1 Q:15A.M..| 124 | 0.78 || 5:10P.M...| 150 | 2.30 |l12:05 P.M....| 124 | 0.82 II:45A.M..| 22r | 1.02 || 8:15 130 | 2.50 || 2:45 P.M.. 121 | 0.69 Siew eee | eee ee ea ec as ek 5:25 P.M.. 120.) 137 me Mal S70 | OBE er eo he pans 8:10 P.M.. 135 | 2-95 He We ke ee es | ae eo Oe at ee Ge, hi Se eh be cet oeerlererre ee ee ee 1 2 3 + 6 ry Ss 2 Hours. suffered no further injury during the period of low temperature (o-4° C.) intervening between the fifteenth and twenty-fourth 1917] BROOKS—PERMEABILITY 317 hours. The disks were still brown and apparently uninjured even after 48 hours in the apparatus. Certain experiments with lan- thanum salts indicated that the effect of lanthanum would resemble that of calcium, differing chiefly in that the alterations of per- meability would take place more rapidly. Summary 1. The protoplasm of Laminaria is normally permeable to the salts of sea water. 2. Sodium salts cause an increase of permeability which cul- minates in death. 3- Calcium and lanthanum salts cause a decrease in per- meability, followed by an increase which culminates in death. LABORATORY OF PLANT PHYSIOLOGY HarvVARD UNIVERSITY EVAPORATION RECORDS FROM THE GULF COAST LAURA GANO AND JEROME MCNEILL (WITH FOUR FIGURES) In connection with field work in northern Florida, undertaken to determine the composition and limits of certain gulf coast forest associations and their relations in succession, and following the instructions of LivincsTon,’ FULLER,? and the work of others in the north and west, records of the daily rate of evaporation in several of the typical plant associations were kept, some of them running through a period of 19 successive months. The Livingston rain-correcting atmometers were used and care was taken to follow the directions for their operation in all particulars. It was planned to visit each station once in two weeks, and this was carried out with few interruptions. Station no. 1 was in an upland hammock forest on Norfolk Fine Sandy Loam. Magnolia grandiflora, Fagus grandifolia caroliniana, and Acer floridanum Pax (or Acer saccharum floridanum Sarg. Silva — N. Am.) were the chief trees, with an undisturbed growth of young trees of these and other species and of mesophytic shrubs and herbs. The apparatus at this station suffered various mishaps, and the record is broken, but from January to May 1913, which includes the times of extreme minimum to maximum evaporation for all the stations (except that of Pinus palustris), the record is complete. Station no. 2 was in an upland oak forest on Orangeburg Fine Sandy Loam, 2.5 miles west of Tallahassee. In this forest nine- tenths of the trees were deciduous, with Quercus falcata, Q. stellata, and Carya alba predominating. Cornus florida was common, but Q. virginiana and Ilex opaca (broad-leaved evergreens) were rare. Myrica cerifera, Rhus copallina, Ilex vomitoria, Ceanothus ameri- canus, Aralia spinosa, Vaccinium stamineum, Callicarpa americana, * Livincston, B. E., Evaporation and plant habitats. Plant World 11:1-9- 1908; Operation of the porous cup atmometer. Plant World 13:111-119- 1919- 2 Futter, G. D., Evaporation and plant succession. Bor. Gaz. 52: 193-208. Igtt. Botanical Gazette, vol. 64] [318 4 1917] GANO & MCNEILL—EVAPORATION RECORDS 319 and Viburnum rufidulum were the principal shrubs about the station and made a rather close shrubbery throughout the woods. The list of herbs shows nothing especially distinctive in the way of species, as they are practically the same as those of the beech and short-leaved pine forests in which stations 3 and 4 were located. Station no. 3 was in an upland short-leaved pine forest about 1 mile north of Tallahassee, on Orangeburg Sand. The mature trees were almost entirely Pinus echinata, but this wood was well advanced in the undergrowth toward the oak-hickory stage; the young half-grown trees of Quercus falcata, Q. stellata, and Carya alba, and also of Q. virginiana and some Fagus grandifolia caroliniana, made one story, under which was a lower growth of Quercus nigra, Q. laurifolia, QO. marilandica, Crataegus spp., Prunus angusitfolia, Cornus florida, Nyssa sylvatica, Vaccinium arboreum, Callicarpa americana, and Viburnum rufidulum, with numerous lianas as Smilax glauca, S. pseudo-china, Cissus spp., Vitis rotundi- folia, Gelsemium sempervirens, and Lonicera sempervirens. Common herbs of the station vicinity were Arisaema Dracontium, Oenothera biennis, Sanicula canadensis, Gerardia purpurea, Mitchella repens, Eupatorium album, and Chrysopsis mariana. Stations 2 and 3 were operated for 19 months continuously without a break or mishap. Station no. 4 was in a beech wood about one-fourth of a mile east of the station in the pine forest. To the west and south of this forest was a short-leaved pine wood in a still later stage than the one in which station 3 was placed. The proportion of deciduous trees was larger and the trees older, while the undergrowth was much less dense, which may largely be accounted for by the fact that this wood had been stocked with hogs and cattle for some years. To the north its character changed quite abruptly, the pines being few and the number of mature deciduous trees not large, but the under- growth was very dense. Throughout this wood (an area of some 40 acres) were scattered beeches of all ages. Magnolias were less common. The beech opening in which the station was located apparently had once been somewhat swampy, although but little lower than the rest of the ground and scarcely wetter except after heavy rainfalls. Asa whole the forest was level and formed part of 320 BOTANICAL GAZETTE [OCTOBER a level hilltop. The soil was mainly Orangeburg Sand, which is a transitional type between the Orangeburg and Norfolk Fine Sandy Loams, and which, as stated in the soil survey, is occasionally found in small isolated patches within the Orangeburg Loam areas, occu- pying slight elevations which have not suffered from erosion. The evaporimeter was placed in the portion of the woods freest from shrubs or undergrowth of any kind, there being comparatively few herbs in the vicinity, those noted being mainly the same as those of the open pine wood, except that the fireweed (Erechtites hieracifolia) was common. This station suffered several interrup- tions during the 18 months of its operation, owing to the pasturing animals and other causes. The four stations described were all on the hills or elevations over 100 ft. above sea level, and none of them suffered from frost. Station no. 5 was established in September 1912, about 5 miles southwest of Tallahassee, on low sandhill soil, a strip of gently rolling yellowish sand, covered with a dense growth of: scrub oaks, only an insignificant part being under cultivation. It has doubtless been a shoal, extending east and west parallel with the edges of the abrupt upland to the north which once formed the shore line. This sandhill area is characterized everywhere by 4 very definite as well as limited tree flora. There are 3 scrub oaks and 2 pines, the latter being scattered. Quercus catesbaea, Q. marga- retta,Q. cinerea, and the long-leaved pines, Pinus palustris and P. car- ibaea, are the species. The chief undershrubs near the station were Asimina pygmaea, Vaccinium arboreum, and V. corymbosum. Ascyrum hypericoides was also noted at this station and appears to be generally ubiquitous, although frequent rather than abundant. The herbs were Asclepias tuberosa, Scutellaria integrifolia, Gerardia purpurea, Eupatorium aromaticum, and Liatris laevigatus. Although the sandhill region is very sparsely inhabited, the records from this station happened to be frequently interrupted by meddle- some hunters as well as by fire, frost, and a cyclone. In the effort to keep the apparatus hidden it was twice moved. The cup was broken by frost on November 28, 1913. Station no. 6 was in a long-leaved pine forest on Norfolk Sand, 4 miles southwest of Tallahassee and a quarter of a mile north of 1917] GANO & MCNEILL—EVAPORATION RECORDS 321 Station no 4. At this station the evaporimeter was broken by frost once in the second winter of its history, on January 11; it was shot to pieces once; and was once in the immediate path of a June cyclone which blew down most of the trees in a track 800 ft. wide. By this storm the cup was demolished but the reservoir was unbroken. The location was then changed a few rods to the east. This station was peculiar in that the trees were essentially like those of the Leon Sand station (no. 7) near Lake Jackson, and the herbaceous plants like those on the sandhill soil. At the outer border of this soil, where the Norfolk Sand and the sandhill join, the scrub oaks gave way abruptly, the line between the two soils being generally as sharp as if the planting had been artificial. e Leon Sand station, no. 7, was in operation more or less continuously for 18 months, being broken by frost once the first winter and twice during the second winter; it was also once in the path of a fire. This Leon Sand is situated 9 miles northwest of Tallahassee, being a strip of long-leaved pine forest about 200 yards wide. This small area is bordered on the north by a slough which is directly bordered by Norfolk Sand, and to the south the soil is the Norfolk Fine Sand, each with characteristic vegetation. This strip of the Leon Sand is an outlying neck of a larger area of the same soil 2.5 miles wide and 1 mile long, the only area of this particular soil in the northern part. of the county which is accessible to the railroad. However, in its growth it is typical of the larger area of the flatwoods to the southeast. This soil, wherever it occurs, is very level and poorly drained and therefore excessively wet a large part of the year. Station no. 7, therefore, was on the wettest soil of any, and its vegetation should be compared with that of station no. 6, which also supported a long-leaved pine forest on the Norfolk Sand, one of the driest soils of the region. The wood on the Leon Sand was very open and the destruction caused by turpen- tining had still further thinned it. Owing partly to frequent fires and partly to the general quality of the soil and the drainage, the undershrubs were very low, seldom exceeding 2 ft. in height. The forest floor was sparsely covered with wire grasses. Apart from the pines, the trees noted about this station were occasional small specimens of deciduous trees, as Quercus falcata, Q. virginiana, Q. 322 BOTANICAL GAZETTE [OCTOBER nigra, Liquidamber styraciflua, Acer rubrum tridens, and Nyssa sylvatica biflora. The undershrubs were Quercus myrtifolia, Q. minima, Pyrus arbutifolia, Rubus villosus, Rhus copallina, Ilex glabra, I. lucida, Hypericum fasciculatum, Vaccinium virgaium tenellum, Viburnum nudum, and V. molle. A common liana was Gelsemium sempervirens, but the most common plant of all was Serenoa serrulata (saw palmetto). The herbs about this station make a distinctive list, the majority being species of Compositae, as Helianthus angustifolius, Rudbeckia laciniata, Aster Tradescantt, Solidago fistulosa, and Bidens bipinnata; there were also Polygala lutea, Viola lanceolata, Sabatia gracilis, S. lanceolata, Pinguicula lutea, and Valerianella radiata. Stations no. 8 and no. g were located in October 1913 in the meadow of the Ocklocknee River. One was placed in a willow growth on the south bank, the apparatus being located in the outer border of the narrow strip of trees edging the stream and 5 or 6 ft. above the water at its normal stages. At this point a strip of bare sand, 15-20 ft. wide, separated the willows from a birch zone. Immediately bordering the river this meadow strip was about one- fifth of a mile wide, bounded on the east by a strip of Norfolk Sand with the long-leaved pines. The area occupied by the willows was subject to frequent overflow and no other plants seemed able to maintain themselves permanently in this zone. The growth here was not luxuriant, few of the trees exceeding a height of 10 or 12 ft. The records from these stations were interrupted by frost about December 21, 1913, and again on January 18, 1914, while from February 1 to March 28.the apparatus was covered by water tw0- thirds of the time and no records were secured. The birch station, 4 ft. higher and 15~20 ft. farther inland than the willow station, suffered similar interruption, except that the interval due to the flood was two weeks shorter and the apparatus was reestablished March 15, at which time the willow station was still completely under water. On the whole, the growth here was more luxuriant, although few of the trees had trunk diameters greater than 6 inches, or height greater than 15-20 ft. Laboratory examination of each of the soils at the several stations was made to determine the organic content and general 1917] GANO & MCNEILL—EVAPORATION RECORDS 323 character. The Orangeburg Fine Sandy Loam soil from the Spanish oak-post oak station, when dried, was a dark brownish gray. It is an excellent soil, rich in humus, and the drainage in the locality of the station was good. The soil from the short-leaved pine station was a medium brownish gray, similar to the preceding but containing a larger proportion of sand (Orangeburg Sand), and less humus. The soil from the beech wood was the same according to the classification of the United States Soil Survey Report, and it resembled that of the pine wood in the samples taken in the course of this study, but both soil and subsoil were of a brighter reddish tinge. The area of the beech station was hardly so well drained as that of the pine wood. The soil from the Pinus palustris forest on Norfolk Sand was very similar in color (both soil and subsoil) to that of the short-leaved pine, but contained decidedly less clay, separating in loose grains when dry, while the other dried in small lumps. It was also less rich in humus. The drainage was excellent to excessive. The soil from the scrub oak forest (which adjoined the preceding on the south) was very similar to Norfolk Sand in texture but a brighter red and perceptibly poorer in humus. The soil from the Leon Sand station was a medium gray sand with a very small admixture of organic materials. It was too wet for agricultural crops. The evaporation records from the mesophytic forest (station no. 1), during the time it was steadily running, showed a consistently lower average and actual rate than any other station. The minimum monthly rate for this station was 6.05 cc. per day in January. The actual minimum was 4.5 cc. in January. The maximum monthly rate was 10.27 cc. daily in April, and the actual maximum was 11.9 cc. the first of May. The mean average rate for the 4 months covering the time from the minimum to the maxi- mum was 8.5 cc. per day, an interesting result in comparison with the record of evaporation for beech-maple forests in the north. Station no. 2, the Spanish oak-post oak forest, in comparison, gave a record of 9.90 cc. per day for the same period of the same year. The average of this station for 18 months’ continuous and unbroken record, however, is 14 cc. daily. The minimum monthly 324 BOTANICAL GAZETTE [OCTOBER average is 9.94 cc. per day in December, and the maximum monthly average is 22.20 cc. daily in April. The actual minimum during the 18 months was 7.01 cc. in October, and the actual maximum was 29.28 cc. in March. The short-leaved pine station, no. 3, averaged 11.67 cc. per day for the same period of the same year as given for stations nos. 1 and 2; and for an 18 months’ unbroken record, 14.22 cc. perday. The minimum monthly average was 8 .83 cc. per day in January, and the maximum monthly rate 19.7 cc. daily in April. The actual minimum was 5.18 cc. in January, and the actual maximum was 25.04 cc.in May. Comparison of stations 2 and 3 thus shows the averages as based on the yearly rate to be very similar. If, how- ever, a comparison be made of their rates during the two general periods for deciduous trees, namely, with full foliage and without full foliage, or summer and winter (from June to November, and from November to June), the comparison shows that the June to November season gave a rate of 12.49 cc. daily for the oak forest, and of 13.8 cc. daily for the pine forest; while the winter rates (November to June) were, respectively, 15.69 cc. and 13.70 CC. This demonstrates a greater evaporation in winter in the deciduous forest, and the greater evaporation in summer from the pine forest. However, the similarity in the yearly rate, covering as it does the extremes of the two years, shows that the evaporation in the two forests was not greatly different, and this may seem related to the fact that at both stations there was an abundance of shrubbery of similar composition; if anything, that of the pine wood, being in two stories, was the thicker, and ay telescoping of these two associations was conspicuous. The beech forest, which had been burned and pastured, gave an average result of 16.63 cc. daily for the whole period of 18 months (with one break in the record for November to December 1912), an average of 11.21 cc. per day for the period from January ! to May 1, 1913, and an average of 13.4 cc. for the summer (full foliage) period. This last compares with the same average of the pine wood, showing a similarity between the pine forest and the pastured beech wood. June shows the minimum monthly rate for this forest, and March the maximum (fig. 1). 1917] GANO & MCNEILL—EVAPORATION RECORDS 325 Station no. 5, that of the scrub oaks, gave 15.52 cc. daily for 18 months, and 15.30 cc. daily for the period from January to May 1913. For the summer (June to November) the average was 13-95 cc. daily, corresponding to the short-leaved pine and the pastured beech wood. The winter rate was 14.1 cc., intermediate between that of the oaks and pine. The period of greatest evapora- tion was April; while December, January, and February showed | | 20 L {atl ie 7 ix | 4 /5 i \ | “INN ; C ot ELS be Oe yee c re va Mb f ” 1 v |_Lo Vf ’ Sep | Oct | Nov.| Dee | an | Feb. | Mar.| Ape | May | Tune | Tuty | Qus | Fic. 1.—Chart showing comparison of yearly range of evaporation in Spanish oak-post oak forest (dotted line); short-leaved pine forest (heavy line); grazed beech forest (broken line). about the same minimum. The actual minimum was 7.39 Cc. in late December, and the actual maximum 27.97 cc. in early May. This forest, therefore, does not show such wide variation for the seasons as do the others given, and the curve representing the years’ averages runs more evenly for this forest than does that of any other except the flatwoods. This evenness may be related to the fact that, although the trees are deciduous, their leaves, after dying and turning brown, remain on the branches most of 326 BOTANICAL GAZETTE [ocTOBER the winter; and as they are coriaceous in texture and more or less coated with felt on the under surface, they remain intact until the time for the new foliage. The low summer rate (as compared, for example, with the long-leaved pine rate) also may have a relation to the fact that. although there is an absence of shrubs or undergrowth of importance, these trees are dwarfed or scrub- like, and the foliage grows low on the trunks; when growing closely they make a thicket-like forest. Seb. | Oct | Mov.| Dec | Jan.| Feb.| Mar-| Abr. | May |Tune | July | Qug ‘ad aa ' 2 IN oS : ee |? £ \ F. \ . wp7ai~ . ER OR / Ne Ps! Fic. 2.—Chart showing comparison of average yearly rates of evaporation in scrub oak forest (heavy line); flatwoods (broken line); long-leaved pines on dry lan (dotted line). Station no. 6, in the dry pine wood, gave the average evaporation per day of 17.9 cc.; 12.28 cc. for the period January to May; 18.25 cc. for the summer period; 19.2 cc. for the winter period; with minimum monthly average of 8.9 cc. in December and a maximum of 32.5 cc.in April. The actual minimum was 4.15 CC. and the maximum 56.19 cc., showing the widest range of any station (fig. 2). 1917] GANO & MCNEILL—EVAPORATION RECORDS 327 The flatwoods station, on Leon Sand, gave an average for 18 months (with a break in the record for December and January . 1912-1913) of 12.99 cc. per day. The January to April average for 1913 is not complete, but for the summer and winter periods the averages are, in order, 13.24 cc. and 11.17 cc. The minimum month is January, 5.94 cc. per day; the maximum in May is 19.8 cc. per day. The actual minimum falls lower than that of any othér, being 3.88 cc. in February, and the maximum was 25.44 cc. in May. The meadow stations were not in operation for a long enough time to give results covering a year. From October to June the willows averaged 12.47 cc. daily, comparable to the flatwoods station. The average for the birch station for the time was 13.98 cc. daily. Their minima occurred in January and maxima in May. Arranging the stations in the order of their yearly averages of evaporation, beginning with that having least evaporation, their order is as follows: hammock climax forest, willow (meadow) zone, flatwoods, birch (meadow) zone, Spanish oak-post oak forest, short-leaved pine forest, scrub oak forest, beech wood (open and grazed), long-leaved pine forest. Omitting the meadow stations, the others arranged in order of increasing rates are (for the summer period June to November), after the hammock forest, the Spanish oak-post oak forest, the flatwoods, the beech (grazed), the short- leaved pines, the scrub oaks, and long-leaved pines. The order, by winter average rates, is flatwoods, short-leaved pines, scrub oaks, Spanish oak-post oak, beech (grazed), and long-leaved pines. The order during the critical period of the year, from January to May (a dry period and a time of sharply rising temperature, cor- responding to the time of vernation of the deciduous trees and o changes of leaves, in part or altogether, of many evergreens), is as follows: mesophytic hammock forest, Spanish oak-post oak forest, beech wood (grazed), short-leaved pine wood, long-leaved pine wood, and scrub oaks. Of these the order of the forests on the clayey soils of the upland is essentially that observed for their succession, the difference in winter being in the place of the leafless Spanish oak-post oak forest as compared with the conifer forest. In the pine and oak forests on the dry sandy soils, the same relation 328 BOTANICAL GAZETTE [ocroBER Sep Oct | Nerv| Dee Jan| Feb | Mar | Abr| Mey| June | Jere | Cel. nS LAY Y Lis \. je Sipe cs us NG Wan AVA oe aes Fic. 3.—Chart showing evaporation rates of 3 pine forests: long-leaved pine on dry sand (heavy line); long-leaved pine on wet sand (broken line); short-leaved pine (light line). Sep.| Oct | Nov. | Dec.| Jan.| Feb.| Mar | Afbr.| May| Tane| Tuly Gug. . ; es fo te Nb = : 4.—Chart showing comparison of evaporation rates, during same year, in the 2 dott rom scrub oaks (heavy line); Spanish oak-post oak forest (light line). 1917] GANO & MCNEILL—EVAPORATION RECORDS 329 holds, the oaks showing a higher winter rate than the pines. The two pine forests (short-leaved and long-leaved) on dry soil are nearest together in their evaporation rates during the spring. A comparison of the three pine associations and the two oak asso- Ciations as charted will show these relations (figs. 3, 4). The Leon Sand forest is singular in that it is so directly related to the soil moisture, and although all other factors tend to make the evaporation excessive, the constant humidity near the soil surface of the ground, owing to the soil saturation, modifies the curve until it is the most equable of any of those described in this report. Ricumonp, Inp. FATS FROM RHUS LAURINA AND RHUS DIVERSILOBA! JAMES B. McNAIR (WITH ONE FIGURE) STEVENS (12) has noticed that the green fruit of Rhus radicans is very poisonous. STEVENS and WARREN (13), when investigating the fruit of R. vernix, found the green fruit highly toxic, while the ripe fruit is harmless. WARREN (15) attributes this interesting change in toxicity to an apparent replacement of acrid resins by wholesome and palatable fats. Besides these species of Rhus, a fat (Japan wax) has been found in 4 species of Rhus: R. succedanea .. R. acuminata DC., R. vernicifera DC., and R. sylvestris Sieb. and Zucc. (6). All 6 of these species are poisonous, and it is interesting to note that the discovery of fat in the fully matured fruit of Rhus laurina Nutt. may add a non-poisonous species to the list. Investigations were begun by me on the fats from Rhus laurina Nutt. and R. diversiloba T. and G. with two objects in view: (1) to discover whether or not these fats are identical with Japan wax, and (2) to determine, if possible, the connection between this fat and the poisonous property of R. diversiloba. This latter problem appeared all the more interesting when the fact became apparent that during the ripening of the drupes their poisonous properties simultaneously decreased with their increase in fat. When the fruits have reached full maturity (when the semi-transparent epidermis loosens and easily falls off from the waxy mesocarp) they are non-toxic. The toxicity was tested by thoroughly rubbing the pulverized fruits, as well as an alcoholic solution from them (concentrated to one-third of the original volume of the fruits), on the skin of a sensitive person. The fats experimented with were obtained by boiling the ripe fruits in 95 per cent alcohol under a reflux condenser. The fat samples were purified by repeated solution, evaporation of the «Contribution from the Rudolph Spreckel’s Physiological Laboratory of the University of California. Botanical Gazette, vol. 64] [33° 1917] McCNAIR—FATS FROM RHUS 331 solvent, and crystallization of the solid matter. The substances thus purified are pale yellow, hard, with a conchoidal and some- what lustrous fracture. Their odor recalls that of tallow and beeswax. Under the microscope they appear to consist of small and large refractive grains. They are insoluble in water, slightly soluble in cold 95 per cent alcohol and ether, easily soluble in hot 95 per cent alcohol (separate on cooling to granular crystalline Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Jan. iG. t mass), warm ether, benzol, petroleum ether, and carbon bisul- phide. They form grease spots when melted on filter paper. That glycerol is probably a constituent is evident from an irritating odor of acrolein evolved when the substances are mixed with powdered potassium bisulphate and heated in a dry test tube. From a consideration of their physical and chemical properties so far determined, the fats from R. laurina and R. diversiloba seem to be similar to Japan wax. This means that similar fats have been found in a non-poisonous and a poisonous species of Rhus. 332 BOTANICAL GAZETTE [OCTOBER The wide variance in the physical and chemical constants of Japan wax obtained by different experiments, and different experi- ments by the same investigators, may have been due to several - factors, namely, adulterations of water, starch, oil of Perilla oci- TABLE I ANALYTICAL FIGURES OBTAINED R. diversiloba R. laurina sce a al Bites 18°5C 0.8987 18°5C ° 13 Gas i BES aes 79 per cent (Hiibl.) | 11.44 per cent (Hiibl.) .| 220.6 iy A elting point....| 53° C. eC, *Mg. sipbged ect per cent alcohol at 20° C. t Mg. KOH per gm moides Linn. (BRANNT 2), tallow (BRANNT), the fact that the fat becomes transparent below its fusing point (18-23.5° F. below m.p., BRANNT), the fact that the melting point becomes higher with the age of the sample (BRANNT), impurities, and different methods of analysis. Morphology of fruit of R. diversiloba in relation to fat formation The ripe fruit of R. diversiloba is oval, 5s-g mm. broad, 4-6 mm. high, and 4-6 mm. thick. When first formed it has a shining grass-green color and smooth texture. When dry it becomes brown and presents long dark stripes which previously were only slightly indicated. The outer surface of these stripes is depressed because of the collapsing of the large resin ducts which lie directly beneath them. The outer layer of the fruit, which is a drupe, is something over 1 mm. thick. In the horizontal cross-section 20-30 large resin passages are present. , These form a single outer row com- pletely around, which conforms with the general outline of the drupe. Many smaller resin ducts are present, which alternate with the wider ones to form a row next to the seed. The arrangement on the top and bottom of the drupe is less regular. The epidermis is bordered by 2 or 3 layers of strong sclerenchymatous cells. Between these border layers and the resin passages lies the paren- chymatous tissue whose cells for the most part. contain solid fat. In 1917] McCNAIR—FATS FROM RHUS 333 the ripe fruit the fat appears in the principal tissue of the mesocarp. Fat is not found in the exocarp, the thin walls and the inner bound- ary of the mesocarp, the sclerenchymatous cells, the cells of the vascular bundles and their sheaths, and the parenchymatous sheaths of the resin passages: The presence of solid fat in the fruit cannot be detected before July. At the beginning of August fat formation is nearly com- pleted. The granulated layer of fat can be seen in the cell between the membrane and the protoplasm. This layer makes the lumen smaller, increases on the outside, and goes in between the already formed fat. Its granular form changes to striated masses. Before the formation of this fat in the fruit a progressive increase in the starch content is noticeable. Starch forms partly in the chromato- phores in the cell and partly in the cells. When the fruit cells are rich in starch the cells contain besides only granular protoplasm and nuclei. This starch gives a positive reaction with iodine. When fat formation is near completion no starch can be detected in the fruit. In fruits which have nearly completed their growth the resin passages are everywhere constricted by the growth of paren- chyma sheaths. From a consideration of these phenomena fat is apparently formed from starch and not from the resin-like poisonous sap. This view does not seem untenable, for it has been proved that in the storage foods of plants carbohydrates and fats are inter- changeable, and in certain cases carbohydrates are entirely replaced by fats. Starch is stored in potatoes and in the tubers of dahlia, and cane-sugar is stored in beet root; the seeds of the two former plants contain oil, while those of the beet are starchy. Although the grains of most grasses contain starch, some instances are known in which fatty oil is present instead (Phragmites communis, Koeleria cristata, etc.). In the cotyledons of Impatiens Balsamina amyloid is stored in the form of enormously thickened walls, while in other species of Impatiens the tissue of the cotyledon is thin-walled and oil is present instead of reserve cellulose. The change of carbohydrates to fats in the seeds of plants has been studied by Scumupt (11), LeCLerc pu SABLON (4), and others. These investigators have shown clearly that as the 334 BOTANICAL GAZETTE caare carbohydrates decrease in seeds the fatincreases. For instance, whee almond seeds first begin to ripen, they are rich in carbohydrates and poor in fats; when fully matured, however, they are poor in carbohydrates and rich in fat. The seeds of Ricinus and Paeonta are also typical cases. It seems as though the oil in the mature Ricinus seed comes from glucose, while that of the Paeonia is formed from starch. As it is possible for the plant to translocate fat as such, provided it be an emulsion sufficiently fine, or in the form of fatty acids and glycerine, it might appear to some that the fats in seeds have not been formed in situ, but have been conveyed there by the sap. It cannot be denied that translocation of fat may occur to a certain extent; but it is a fact that fats will appear as the carbohydrates disappear in immature seeds even when removed from the parent plant. This fact, when considered with the facts known regarding the formation of fats in vegetative organs under the influence of cold, leads to the inevitable conclusion that fats are formed at the expense of carbohydrates and that this trans- formation may occur 7 situ. Scumipt (11) and LECLERc pu SaBLon (4) have shown con- clusively that during the germination of oily seeds a reversal of this process takes place, carbohydrates being formed apparently from fat. The processes by which carbohydrates are changed to fat are still unknown. As the carbohydrates do not contain such complicated carbon chains as the fats, the formation of fat from carbohydrates must consist of a synthesis, in which the CHOH group is converted into CH.; hence a reduction must occur. The formation of fat from ‘carbohydrates in the plant has its parallel in the animal. The great influence of carbohydrates on fat formation in the animal was observed and proved by LAWES and © GILBERT (5), Voir (14), Lummert (7), and many others by means of a series of nutrition experiments with different animals, with foods especially rich in carbohydrates, who have apparently proved that a direct formation of fat from carbohydrates does actually occur. The fat of the poison oak fruit is not a reserve food supply for use of the cotyledon; this is shown by morphology and sprouting. 1917} MCNAIR—FATS FROM RHUS 335 When the drupe is planted, the growing embryo does not utilize the fat, as it remains unchanged. The fat, however, may be of service to the seed as a protection against cold on account of its low power for heat conduction, increasing its chance of dispersal by streams, as it is far lighter than starch (specific gravity of starch 1.56, fat 0.9872); as a protection from rain and humidity; as a pro- tection from fungi (PFEFFER 9); and as an attraction to birds and therefore a factor in seed dissemination. The ripe fruits persist on the plant during the winter, long after the leaves have fallen, some until May. Birds, therefore, can see them for.a long distance. When eaten,,the fatty covering of the drupe only is digested; the ejected seeds can still germinate. Mésrus (8) has observed the fruits of R. vernicifera eaten by half-wild pigeons at Frankfurt. REINECKE (10) has recorded the doves of Samoa as eating the fruit of R. tahitensis. BARRows (1) speaks of the con- sumption of the fruit of R. venenata and R. Toxicodendron by the crow. After eating the fruits the crow rapidly digests the nutritious pulp and ejects from the mouth (in less than 40 minutes after eating) the seeds clean and devoid of pulp, together with the sand swallowed to aid in digestion. Of these ejected seeds go per cent germinated. Bryant (3) has observed that the favorite food of the roadrunner (Geococcyx californianus) during the winter season consists of the fruit and seeds of R. integrifolia. Unlike many birds which turn their attention to vegetable food during the winter season, the roadrunner appears to discriminate as to the kind of seeds taken. Of the stomachs examined, those of 26 (31.3 per cent) contained the seeds or fruit of R. integrifolia, and 8.4 per cent of the food taken by all the birds was made up of this element. The attention of the roadrunner is apparently attracted to this vegetable food only during the winter season, when insects, lizards, and other kinds of food are least abundant. Summary 1. Substances more similar to Japan wax than to any other fat have been isolated from the ripe fruit of R. Jawrina and R. diversi- - 336 BOTANICAL GAZETTE [OCTOBER 2. A decrease in the poisonous properties of the fruit of R. di- versiloba occurs simultaneously with the increase in fat content. 3. The decrease in the poisonous properties in the ripening of the fruit of R. diversiloba eventually results in the fruit becoming non-toxic. This phenomenon is not necessarily due to a chemical transformation of the poison into fat for: (a) subsequent to the formation of fat the cells in which it is deposited become filled with starch; (b) it is possible for the plant to transform starch into fat; (c) fat is not formed in the parenchymatous sheaths of the resin passages; (d) consequent upon the formation of fat, the resin passages are everywhere constricted by the growth of parenchyma sheaths; (e) a similar fat has been found in the fruit of a non- poisonous species of Rhus. I am indebted to Professor T. BRairsrFoRD ROBERTSON for having placed the resources of his laboratory at my disposal during this investigation. PASADENA, CAL. LITERATURE CITED 1. Barrows, W. B., The common crow of the United States. U.S. Dept. Agric., Div. Ornith. and Mammal. Bull. no. 6:85-87. 1895. 2. BRANNT, W. F., Animal and vegetable fats and oils. London. 1896 (pp. 138-141). : 3. Bryant, H. C., Habits i food of the roadrunner of California. Univ. Cal. Publ. Zool. 17:29 4. Du SaBion, LE Cane ak Rend. 117: 524. i 119:610. 1894; 123:1048. 1896; Rev. Gen. Bot. 7:145. aes 2 313- 5. Lawes and GirBert. Phil. Trans. part 2. 6. LewkowITcu, J., Chemical technology and abe of oils, fats, and waxes. London. 1914 (vol. II, p. 650). 7. : Pfliiger’ s Archiv. 71:—. 8. Mézsrus, M..——. Ber. Deutsch. Bot. Gesells. 15:435. 1897- 9. PFEFFER, Mw, Physiology of plants, transl. by A. J. Ewart. Oxford. 1g00 (Pp. 4 10. Sakis ¥, Ber. Schles. Gesells. 73: part 2, 75. tz. ScHmipT, ——. Flora 74:300. 1891. 12. STEVENS, A. B., Poison ivy fruit. Amer. Jour. Pharmacy 80:93- 1908. 13. STEVENS, A. B., and WARREN, L. E., Poison sumac. Amer. Jour. Phar- macy 79:499. 1907. 14. Voir, ——, Respiration. Sitzungsb. Miinch. Akad. 15:51. 1895- 15. WaRREN, L. E., ——. Pharm. Jour. 1909. CURRENT LITERATURE NOTES FOR STUDENTS Crown gall.—Recent developments in the study of crown gall and its rela- tion to animal cancer have been presented by Smira in several papers. The first? of these, in point of completion although not in time of publication, is a succinct account of remarkable growth phenomena resulting from the action of Bacterium tumefaciens when inoculated into special tissues of plants. Four cases are Sistngnshet 1. Whent dal cambium is inoculated, this tissue loses its tendency to form mature structures having definite orientation. Instead, the cells continue to divide rapidly, forming large masses of mostly embryonic par- enchyma within which scattered and irregularly arranged xylem and phloem elements are differentiated. The process recalls that described by Lamar- LIERE? in the galls of Gymnosporangium and aptly designated by him as “parenchymatization.” 2. When the cortical parenchyma is infected, a somewhat similar develop- ment takes place. The cell divisions succeed each other so rapidly that the cells in the proliferating tissue remain small in comparison with the normal parenchyma, and appear to remain continually in an embryonic state. In time, however, there is a tendency to develop vascular elements, and these are then arranged in a more or less well defined stele. The vascular system of such . tumors has no connection with that of the stem, consequently the galls die from imperfect nutrition and lack of water. The galls of these two t exhibit no external differentiation. They include all the forms of crown gall described in former papers. 3. A more remarkable condition is brought about when the crown gall organism is inoculated into the leaf axils of young growing plants (species of Pelargonium, Nicotiana, Lycopersicum, Citrus, and Ricinus). The tumors ae | 1 P nape vei Asem +, t SMirH, Erwin F., Crown gall a changed stimulus. Jolie: Agric. Research 6: ae pls. 18-23. 1916; see also Le cancer est-il une maladie du regne végétal? Premier Congress Internat. Path. Comp. Vol. II. 1912; Cancer in plants. Proc. 17th Internat. Souiies of Medicine. Vol. III. Pathology. London. 1913; Further evidence as to the relation between crown gall and cancer. . Nat. i i tha crown gall of plants is cancer. Science 43:871-889. 1916; Chemically induced crown galls. Proc. Nat. Acad. Sci. 3:312-314. 1917. ? Rey. Bor. Gaz, 427153. 1906. 3 Rev. Bor. Gaz. 52:75. I91I; 55:257- I913- 3 338 BOTANICAL GAZETTE [OCTOBER thus produced are covered with abortive leafy shoots or with flower shoots if a flower incept has been disturbed. On tobacco plants these teratoid tumors may give rise to secondary tumots similar in nature. These daughter tumors are connected with the parent growths by tumor strands which are quite different in structure and location from those occurring in galls of the first two classes. The tumor strands heretofore described were found in the Paris daisy. They arise in the region of the primary xylem and consist of par- enchyma tissue. The new tumor strand found in the tobacco occurs in the cortex. It consists of a concentric bundle with the xylem surrounded by the phloem. The daughter tumors arise at mocha along the strand and often have all i Aue mics of the parent tum st case, even more remarkable, ca when the young leaves of tobance foie are infected with the crown gall organism. From such infec- tions on the midrib and lateral veins tumors arise which produce leafy shoots. These tumors the author regards as akin to teratoid tumors in animals. The fact of their development is another proof that any plant cell not fully matured may retain the capacity for developing the whole organism n another paper,‘ written for medical readers, the salsioet of crown gall is discussed in its relation to the problems of human cancer. The general resemblances in mode of growth, cell multiplication, occurrence of tumor strands, and production of secondary tumors in the two classes of growths are pointed out. The materials presented in this paper are essentially those of earlier papers, together with the new facts of the paper reviewed above. The phenomena, however, are described in greater detail, and considered boa special reference to their bearing on animal pathology. Here, as in other cases, the author relies mostly on numerous excellent photographs for the vheacuratien of his evidence. n explaining his standpoint with reference to the bearing of his work on the problems of animal cancer, the author makes no claim that the causal organism of the crown gall has any relation to human cancer. It is pointed out, however, that this organism induces in plants a set of phenomena which have a st g parallel in the manifestations of animal cancer. Such phenomena are the growth without function shown by gall tissue, the persistently embryonic character of the proliferating cells, the lack of orderly differentiation of the tumor tissues, the existence of tumor strands giving rise to daughter tumors repeating the structure of the parent gall, and the occurrence of galls resembling embryonic teratoids. It is further pointed out that in the crown gall the cell, although apparently possessing invasive capacity, is not itself the parasite, as 4SmitH, Erwin F., Studies on the crown gall of plants; its relation to human cancer. Jour. Cancer Reseuich 1:231-258. pls. 1-25. 1916. sIt appears that the embryonic tissue of the gall to a certain extent pushes in among the cells of the sound tissue, a phenomenon which distinguishes this gro wth from other plant galls induced by fungous 0 ranimal parasites. The mode of progress 1917] CURRENT LITERATURE 339 JENSEN thought. On the contrary, the behavior of the cell is due to an invading specific microorganism. These facts, together with the observation that in one case at least (Rous’ sarcoma of fowls) the abnormal growth can be produced by some sort of material separable from the cells and capable of multiplying when injected into other tissues, are regarded by the author as greatly advan- cing the contention that animal cancer is due to an intracellular parasite. ey anterenting results® were obtained in a series of experiments designed to f tumor growth in crown gall. In this investigation the author was guided by the hypothesis that the sub- stances produced in the metabolism of Bacterium tumefaciens must be the direct cause of the cell proliferations. To the end of determining the effects of such substances various plants were injected first with compounds which chemical studies had shown to be products of the causal organism, and finally with a large number of other substances. The first experiments were conducted with ammonia, which in various concentrations was injected into the stem cavity of Ricinus and into the fruit cavities of young green tomatoes. The result of these injections was an abun- dant formation of cushion-like intumescences within the cavities in both cases. Later, proliferations of the same type were obtained by the injection of a large number of other substances, including ammonium salts of organic and of inorganic acids, dilute solutions of the acids themselves, salts, glucose, and Saccharose, and in some instances to a slight extent with distilled water. In many cases when the tissues of the pith cavities of Ricinus were exposed to weak ammonia vapors from dilute solutions of ammonium phosphate or ammonium carbonate in tubes sealed into the hollow stems, proliferations were produced not only in the cavities the reagents but also in many inter- nodes above and below the opened one. The action in these cases, therefore, took place at a distance through thick partitions. The most striking result was obtained from the injection of a 5 per cent solution of ammonium dihy- drogen phosphate into a very young internode of Ricinus. In this instance the pith cavity became completely filled by the proliferating pith, and from this tissue a complete vascular cylinder was differentiated. The orientation of the new inner cylinder was the inverse of that of the normal cylinder, the phloem being at the center and the xylem occupying the outer region. Such a complete cylinder was observed only once, but in many instances isolated of the tumor strand through the tissues is not yet clear. Whether this structure pushes its way through the pith or cortex by apical growth after the manner of the internal roots of lycopods, or whether progress through the tissues is accomplished by successive cell-invasion by the bacteria and subsequent differentiation of the in- vaded cells into the characteristic tumor strand, has not yet been determined. From eek of his stained sections Samir thinks that both types of invasion occur. Erwin F., Mechanism of tumor growth in crown gall. Jour. Agric. mis 8:165-186. pls. 4-65. 1917. 349 BOTANICAL GAZETTE [OCTOBER concentric bundles were produced in the proliferating pith. In these the phloem was always at the center of the bundle. Such bundles, the author points out, occur normally in the axes of the inflorescence of Ricinus and in the nodes. Superficial intumescences similar to those reported by VON SCHRENK’ were produced on cauliflower by exposure of the plants to vapors of ammonia and of acetic acid mixed with alcohol. e outgrowths here described all partake of the nature of intumescences frequently observed in plants. In some cases, indeed, as in the instance de- scribed of the complete filling of the pith cavity and the subsequent differentia- tion of a vascular ring, the outgrowth is excessive. This behavior leads the author to the belief that if the stimulus could be continually applied, one would have a condition resulting in the production of tissue masses not unlike those of crown galls. Since in his experiments the outgrowths also resulted from the presence of many substances not the product of parasites, the author is inclined not to attribute the effect to the specific chemical action of any compound, but seeks for an explanation in some property common to all the compounds regard- less of chemical composition. Such a common characteristic he finds in their osmotic action, to which, rather than to chemical sana gatecrey he — their effect. In this ection it is of interest to recall produced by Arxrinson,? Miss Douctas,? and STEINER” by ahi plants to conditions increasing water absorption and diminishing transpiration; and by Soraver, KiisteR, von ScHRENK, and others as a result of application of solutions. In the author’s own work the intumescences were mostly the result of injection of solutions, but in some instances they resulted from the injection of water. It is improbable that the osmotic disturbances induced by the appli- cation or injection of water are the same as those effected by the application or injection of solutions. The fact that the various disturbances produce responses differing only in degree would seem to indicate that the causes deter- mining the formation of intumescences have not yet been fully analyzed into their separate factors. It is not unlikely that different plants react differently in this respect. The experiments of STEINER would seem to indicate that such a possibility exists —H. HassELBRING. Taxonomic notes.—GarTeEs" has attacked the genus Polygonatum, which he says “‘has been in a very chaotic condition owing to the lumping of species, the transference of names, and the confusion of North American with European 7 Rev. Bor. Gaz. 40:390. 1905. ® Arxinson, G. F., Oedema of the tomato, Cornell Univ. Agric. Exp. Sta. Bull. 53:77-108. 1893. 9 DouGLAS, igh G. E., The formation of intumescences on the potato. Bot. 1907. 10 Rev. fem Get 402391. 1905. . -™%Gares, R. R., A revision of the —_ web a een in North America. Bull. Torr. Bot. Club 44: 117-126. pls. 4-6. 1917] CURRENT LITERATURE 341 species.” He recognizes 9 North American species, giving under each the full synonymy and citations of exsiccatae. The amount of change is indicated by the fact that the revision includes a new species combination, a new variety, and 3 new variety combinations. Komwzumr” has published some studies of the plants of oriental Asia, Sessibiee new species and varieties. Notable among the genera is Morus, of which 25 species are enumerated, 4 of which are new. MooreE,* in connection with descriptions of numerous new species of African Compositae, has established a new genus (Paurolepis) belonging to the Vernonieae. NAKAI,™ in continuing his studies of the flora of Japan and Korea, has described 21 new species, mostly in genera familiar in this country. The completed studies will furnish much additional evidence of the close relation- ‘ship of the Japanese and North American floras. Payson, in studying the American perennial scapose species of Draba, recognizes 26 species, 14 of which are described as new. The new species are from Utah, Nevada, California, Oregon, Idaho, and adjacent Canada. Povau,” in concluding his studies of Mucor, has presented a taxonomic description of the 18 species investigated. In view of the fact that his experi- mental work showed that the species of Mucor are usually plastic organisms, varying especially with the substratum, it seemed desirable to attempt a standardization of cultural requirements, by investigating as many species as possible under the same cultural conditions. The 18 species described were studied from uniform, standard bread cultures, and 6 of them are describe as new Sir"? has described a new genus (Parasyringa) of Oleaceae from China. TRANSEAU® has published a list of the algae of Michigan, based chiefly upon collections made by him during the summer of 1915, in connection wi the M pens se bea es —— by other collections. Since number of years, the records no work on 7 Komzumt1, ore Contributiones ad floram Asiae Orientalis. Bot. Mag. Tokyo 31:31-41. 73 Moore, — LeM., Alabastra diversa. XXVII. Jour.- Botany 55:100- 106. pl. 547. 1917 ™4 NaKal, TAKENOSHIN, Notulae ad plantas Japoniae et Koreae. a Bot. Mag. Tokyo 31:97-112. 1917. 5 Payson, E. B., The perennial scapose Drabas of North America. Amer. Jour. Bot. 4:253-267. 1917. %6 Povan, ALFRED H. W., A critical study of certain species of Mucor. V. Taxo- nomic. Bull. Torr. Bot. Club 44:287-312. pls. 17-20. 1917. Suita, W. W., Note on Parasyringa, a new genus of Oleaceae. Trans. and Proc. Bot. Soc. Edinburgh 27 1193-96. 1916. * Transeav, E. N., The algae of Michigan. Ohio Jour. Sci. 17:217~232. 1917. 342 BOTANICAL GAZETTE: [OCTOBER for species are for the most part new to thestate. The list includes 226 species, and among them there is a new species of Oedogonium (O. americanum), and new varieties of Vaucheria geminata and Oedogonium undulatum. AN ALDERWERELT,” in continuing his studies of Malayan pteridophytes, has described 27 new species of ferns, among them a new genus (Campylo- gramma), 11 new species of Lycopodium, and 7 new species of Selaginella.— j. M. Cc. Direct reading potentiometers.—The electromotive force of the hydrogen electrode bears a logarithmic relation to the normal hydrogen-ion concentration H-+ of the solution. Where large numbers of determinations are concerned, the calculation of the reaction of the solution in terms of normal acidity be- comes laborious, An attempt to simplify the process was made by SORENSON, who introduced the Ph values.* Since the Ph value is the negative logarithm of the hydrogen-ion concentration, the relation existing between these numbers and the usual method of expressing acidity in terms of normality is not always clear. Bovie” has devised a potentiometer which reads directly in terms of hydrogen-ion concentration. In the original article a full discussion is given of the method of operating the instrument, as well as we the CoS ERCLO® of the dip electrode to be used in titrations. Thi the operator to titrate a solution to a definite hydrogen-ion concentration and thus peat the error due to misjudgment of the end point as found by the indicator method. Another advantage of the instrument is that it makes it possible to titrate two different acids in the same solution or to titrate successively the hydrogen ions of polyvalent acids or acid salts. It also makes possible the titration of such acids as boric acid, which give an end point on the alkaline side of the neutral ae of distilled water. The author gives a number of other very useful applications for the instrument. The apparatus is very well adapted for mak- ing large numbers of determinations rapidly and with an accuracy sufficient for ordinary purposes. Using logarithmic resistances instead of the logarithmic scale, BARTELL” has devised a similar apparatus, which avoids the sources of error in the BovIE apparatus and gives a greater accuracy. It is not expected that this type of potentiometer will replace the older forms which are adapted to reading very small potentials.—R. B. Harvey. 9 Van ALDERWERELT, Capt. C. R. W. K., New or interesting Malayan ferns. 8 and 9. Bull. Jard. Bot. Buitenzorg nos. 23 and 24. pp. 27 and 8. pls. 4. 1916 and IQI7- 2 Bovig, W. T., A direct reading segura for measuring and recording both the actual and total reaction of solutions. Jour. Med. Research 33:297- 1915- BarTELL, F. E., A direct a ionometer. Jour. Amer. Chem. Soc. 39:63°- Igi7- 1917] CURRENT LITERATURE 343 Mottling in citrus leaves.—JENSEN™ has attempted to see whether there is any relation between mottling of Citrus leaves and the supply of nutrient salts necessary for chlorophyll formation. Such was thought possible since the Office of Biophysical Investigations had found that mottling is inversely proportional to the humus content of the soil, and that decomposing organic matter increases the soluble salts in the soil:of the groves. The following statements from h 'y indicate t Its of the investigation: ‘Judged by a comparison of the average percentages of the inorganic elements deter- mined in healthy Citrus leaves and in leaves in the medium stages of mottling, the data obtained did not show that the initial mottling could be accounted for by deficiency in the transfer of the iron, calcium, magnesium, and phosphoric acid from the conducting system of the leaf stem and midrib to the mesophyll tissue. On the other hand, sharply localized yellow areas in old orange leaves contained less of these elements than the adjoining green areas (mostly veins), but whether that relation obtained in the initial stage of mottling was not determined. In very badly mottled Citrus leaves there was in general an increase in the percentage of these elements in the conducting tissues, includ- ing the leaf stems, indicating difficulty in their transfer to the inesophyil tissues in very —— stages of mottling, probably because the leaf had become functionless. ‘The process of mottling is seemingly very complex, involving as it likely does an unusually rapid decomposition of chlorophyll and not merely a cessa- tion in chlorophyll formation. This problem may yield to solution, if at all, only after a many-sided attack. In some of the algae, however, loss of chloro- phyil seems to be a direct result of shortage of nitrate supply. Work of this this as a possibility in Citrus plants, as well as to indicate the complex nature : of the process. —Wwm. CROCKER. Monocotyledony.—WorsDELL® has criticized the reviewer’s view of mono- cotyledony in a paper which “‘is an astonishing one.” In fact, we seem to be mutually astonished, neither being able to understand the reasoning of the other. The paper opens with an account of “an uncommon abnormality,” which consists of a ‘forked coleoptile”’ in a corn seedling, and this phenomenon is the excuse for the rest of the paper. It may be well to record that this “forked coleoptile” is a very common phenomenon, as all know who have had much to do with corn ‘Seedlings 1 ” nets eeitivarios. The author h f zonation , which are fundamental in this connection, and zonation is by no means a “s phenomenon.” Zonation enables one to realize, for example, that a prominent, # Jensen, C. A., Composition of Citrus leaves at various stages of mottling. Jour. Agric. Research 9:157-166. 1917. %3 WorspELL, W. C., The morphology of the monocotyledonous embryo and of that of the grass in particular. Ann. Botany 30:509-524. figs. 10. 1916. 344 BOTANICAL GAZETTE [OCTOBER projecting stem tip and a meristematic region that later develops such a tip are of the same ontogenetic significance, and therefore that a cotyledonary ring may be lateral even if the stem tip is not organized. The cells that are to organize it later are still apical. It certainly also gives a aS and more consistent interpretation of the grass embryo than to imagine a cotyledon consisting of such distinct structures as scutellum, — and coleoptile, distinct in origin as well as in position and appearance. The author disposes of the dicotyledonous embryo of Agapanthus as meaning a RRR: char- acter, from which we are to infer that he still maintains the view that the dicoty- ledons have been derived from the monocotyledons. We had assumed that this view was no longer under discussion.—J. M. C Temperature and viability—WAcGONER™ finds that the resistance of radish seeds to high temperature is inversely proportional to the initial water content at the time of heating. At effective temperatures the water content fell with duration of heating. Three different varieties studied showed similar resistance. WAGGONER finds that much of the past work on resistance of seeds to high temperatures lacks precision because the operators allowed the water content to vary greatly during heating. They heated in water in open dishes, in the oven, or in dry corked flasks. The water absorbed or given off by radish seeds during heating as determined by the use of one or the other of these methods goes far to determine their resistance to heat. GRroves*® has taken care of this source of error by securing his seeds gas-tight in tubes just large enough to hold the roo seeds, thus leading to a rapid rise of vapor pres- sure with heating and an equilibrium between the vapor of the air and the water content without measurable water loss. It is interesting to see that radish seeds can be dried down to 0.4 per cent moisture without injury, for EwartT® has concluded that the sorts of seeds that are most resistant to drying cannot withstand a moisture reduction below 2 or 3 per cent without injury; while seat —_ and Populus will not withstand any drying in a desiccator.— Wm. Cro Organic nutrition of plants.—KNupson” has investigated the influence of certain mono- and disaccharides, added to nutrient media, on the growth of various green plants, as corn, peas, radish, vetch, etc. These plants can absorb through the root system and utilize sugars in growth. The order of the sugars with reference to beneficial effects varied with the kind of plant. Thus with corn grown in the light, the order was glucose and fructose, saccharose, maltose; Wacconer, H. D., The viability of radish seeds (Raphanus sativus L.) as effected by high temperatures and water. Amer. Jour. Bot. 4:299-313. fig. I- 1917- *s Bor. Gaz. 58:169-189. 1917. % Ewart, Proceedings and Trans. of the Liverpool Biol. Soc. 10:185-193- 1896. *1 Knupson, Lewis, Influence of certain carbohydrates on green plants. Cornell Agric. Exp. Sta. Mem. 9:1-75. 1916. 1917] CURRENT LITERATURE 345 while with Canada field peas it was saccharose, glucose, maltose. lactose. Timothy was found to utilize lactose when grown in darkness, but not when grown in light. The influence of the sugars upon the rate of respiration in the vetch was observed, with the result that saccharose, glucose, and maltose accelerate respiration very noticeably, the latter somewhat less than the other two. Galactose was found to be toxic to wheat, peas, corn, and vetch, even at low concentrations; while glucose antagonizes the toxicity of galactose, possibly by rendering the roots impermeable to galactose, or by altering galactose metabolism in such a way as to prevent formation of toxic oxidation products. The author suggests as a general conclusion that soluble organic substances produced from humus during decay may play a more important rdle in the organic nutrition of plants than we have hitherto thought.—CuArLEs A. SHULL. Osmotic pressure in parasite and host.—Using the cryoscopic method, Harris and LAawrENcE® have studied the osmotic relations between 7 species of Jamaican mistletoes and their 19 hosts. They that the sap concentra- tion of the chlorophyllous tissues of the parasite is nearly always higher than that of the mature leaves of the host, the parasites showing an average con- pressure. This relationship is not a nec one, however, for in several cases the parasites possessed sap of a lower concentration than their hosts. In such cases it is assumed that the host supplies more than sufficient water to meet its own needs, so that the parasite is not in direct competition with the leaves of the host, but merely secures water from the same transpiration stream. In cases of secondary parasitism, the osmotic pressure increases from host to primary and from primary to secondary parasite. The sap from the stems of leafless species of Dendrophthora possesses a lower concentration than that from leaves of species of Phoradendron and Phthirusa. The meaning of this is not discussed. It may involve differences in the rate of photosynthetic activity in the leafless and leafy forms.—CHARLES A. SHULL. Galls.—Essic” calls attention to the introduction of the chrysanthemum gall fly from Europe. This pest was not known in the United States previous to 1915. It causes cone-shaped galls which often distort the shoot beyond recognition, and eventually causes death of the infected parts. It sometimes destroys one-third of the crop. WELIs* gives us a very important study o the galls of the blackberry The purpose of the paper is threefold: (1) a study of the histology of the galls; 8 Harris, J. ARTHUR, and LAWRENCE, JouN V., On the osmotic pressure of the Kage — of Jamaican Loranthaceae parasitic on various hosts. Amer. Jour. Bot. 3:438-455. 1916. > ieee E. O., The chrysanthemum gall fly, Diarthronomyia hypogaea F. Low. Jour. Econ. Ent. 9:461-468. 1916. %* WeLts, Bertram W., The comparative morphology of the zoocecidia of Celtis occidentalis. Ohio Jour. Science 16:249-290. pls. 8. 1916. 346 BOTANICAL GAZETTE [OCTOBER (2) a study of the galls of Celtis occidentalis; (3) a comparative study of struc- tures. The work is exceptionally well done and well presented. There are kn pe lepidopterous galls are kataplasma in character, and the hemipterous and dipterous galls protoplasma in character. This latter type is more closely comparable to the normal plant parts, but the tissue forms are new. e author very properly suggests that zoocecidology presents a unique field for the study of problems pertaining to the mechanism used in the expression of hereditary characters.—MEL. T. Coox. Germination of rice.—Nacar has made rather an extensive general study of the germination of rice, touching many points that have previously been worked out on other seeds. The cutinized inner integument of the ripe fruit is a semipermeable membrane. Such membranes have been found in the fruit walls of many grasses and in the coats of many seeds. Desiccated seeds of rice are not injured by steeping for 24 hours in ether, chloroform, absolute alcohol, acetone, and other substances. This is in accord with the work of BEQUEREL and of SHULL,33 who have found that the dry coats of many seeds are impervious . such substances, but that, as the water content of the coats rises, they become more pervious. Rice germinates in an extremely low partial pressure of oxygen, yet the germination is abnormal, the hypocotyl growing only under considerable oxygen pressure. Acids and bases show no stimulative effects upon the germination of rice. A few hours of exposure to liquid air does not injure the seeds of rice or buckwheat. Two hours’ exposure to 97- ° C. kills Zea Mays, but does little injury to rice, especially if it is desic- cated.—Wm. CROCKER. Alkalies and salt absorption.—As a phase in the analysis of the tees of alkalies upon the development of plants, BREAZEALE* has studied the effect of NaCl, Na.SO, and Na,CO; upon the absorption of nitrates, phosphates, and potash by wheat seedlings. Up to 1000 ppm. in a nutrient solution they do not affect the absorption of nitrates. In this concentration NaCl does not modify phosphate absorption, but slightly depresses potash absorption. In 1000 ppm., NazSO, depresses the absorption of potash and phosphoric = to approximately 70 per cent of that of the checks. In equal mol co Na,CO; depresses the absorption of potash to 20 per cent and phosphoric er to 30 per cent normal. With Na,SO, these depressing effects were evident in 300 ppm. The writer thinks the depressing effect of the Na2SO, is due to its 3t NAGAI, vagrant Some studies on the germination of seeds of Oryza sativa. Jour. Coll. Agric., Imperial University Tokyo 3:109-155. 1916. ® Bor, Gaz. 56:169-199. 1913; 63:373-397. 1917. 33 Bot. GAZ. 56: 169-199. 19 REAZEALE, J. F., Effect os al salts in water cultures on the absorption of plant food wheat seedlings. Jour. Agric. Research 7:407-416. 1916. 1917] CURRENT LITERATURE 347 reaction with CaCO; of the substratum, thus forming Na,zCO;. Extensive studies of this sort can add much to our knowledge of the absorption of salts by plants and intereffects of salts upon each other as regards absorption.— Wm. CROCKE Calcium compounds of the soil.—Under this titles E. C. Saorrey, W. H. Fry, and W. Hazen, members of the Bureau of Soils, have analyzed 63 soil samples of 23 types from 24 locations of 19 states. They have calculated the percentage of calcium combined with humus compound, calcium carbonate, calcium sulphate, and calcium as difficultly and easily decomposed silicates. They find a wide variation in total calcium content and in calcium carbonate and the two classes of silicates, and there was no constant relation between the total calcium content and the percentage of any of the calcium compounds. Calcium combined with humus compounds was absent in 29 soils. type which is recognized as a good alfalfa soil is characterized by high calcium content, but low content of calcium carbonate. This indicates, as does other evidence, that alfalfa requires a rather high content of calcium ion as a nutrient or balancer of the soil solution, rather than merely calcium carbonate as a neutralizer of acidity —-WM. CROCKER. Phylogeny of ferns. —Bower,® in continuation of his phylogenetic studies of the ferns, has developed some obs iie conclusions in reference to what he calls the “‘acrostichoid condition,” meaning the spreading of exposed sporangia “uniformly over a considerable area of the sporophyll.” This fact was the basis of the old genus Acrostichum, which Bower has come to regard not as a natural genus, but as a state or condition which may have been attained along a number of phyletic lines. In the present paper he has presented a number of genera which he regards as “‘dipterid derivatives,” that is, derived from a phyletic stock characterized by Dipteris, which show various stages of advance toward the acrostichoid condition. According to this view, a number of so-called genera of ferns are form genera, not being what Bower calls “phyletic unities.”” The increasing evidence of parallelism in evolution is raising the question of ~ Phyletic unity” in connection with all of our larger genera.—J. M. C. Pine forests of Virginia and the Carolinas.—Harper®” recently devised a method for securing a rough quantitative analysis of vegetation from notes taken at frequent intervals from the car window or while walking through the country. He made such notes during 53 hours of railroad travel and 21 hours 35 Jour. Agric. Research 8:57-77. 1917. Bo ., Studies in the phylogeny of the Filicales. VI. Ferns showing the ““acrostichoid ” condition, with special reference to dipterid derivatives. Ann. Botany 31:1-39. pls. 1, 2. figs. 15. = 37 Harper, R. M., and vegetation of northern Florida. Ann. Rep. Fla. Geol. Survey 6:163-437. ro 348 BOTANICAL GAZETTE — [OCTOBER - of walking in Virginia and the Carolinas. To obtain the relative abundance of species in the area involved3* he counted the number of times each species was mentioned in the notes, and multiplied the figures for Pinus Taeda and P. palustris by 5, and for the other conifers by 3 before calculating the per- centages. The figures for smaller trees were divided by 2 or by 10, for shrubs by 100, and for herbs by 500. The results were tabulated and are rather interesting. Some estimates of annual increment of the whole vegetation, of the amount of mineral matter taken each year from the soil, and of the amount of water transpired are based upon these analyses. —GrEo. D. FULLER. Forest sanitation—In a recent bulletin MerrNecKE? emphasizes the importance and also the difficulties of giving phytopathology a proper place in forest regulation. He elaborates methods of investigation and application, exemplifying by an actual study of Abies concolor. Forest sanitation is the keynote of the remedial measures proposed, a system of forest regulation which will give proper attention to the removal or destruction of diseased indi- viduals from the community. It is also interesting to note that Wetr,* after discussing the character and nature of the injuries due to various mistletoes, outlines methods of forest sanitation consisting of directing cutting so as to effect the removal of diseased © communities and individuals. Such methods of forest sanitation he believes ill become increasingly practicable with the increasing demand for cutting privileges in the National Forest Reserves —Gro. D. FULLER. an sand dunes.—In a recent bulletin SaANForD® estimates that weds dunes stretch for over 400 miles along shore lines of the state of Michigan and cover not less than 550 square miles of its territory. In the southern peninsula, with the removal of the forests, many of the dunes are becoming active again and now constitute a menace to valuable fruit growing lands. The importance of maintaining a forest cover is pointed out, and the various recognized methods of dune reclamation are described. The failure of certain efforts to control dune movement by planting is shown to be due to a dis- continuance of work before the final cover of permanent forest growth becomes established. Such plantings made by the government at Manistee in 1902 resulted in a temporary cover, which a small amount of subsequent planting 38 HarPER, R. M., A quantitative, ‘hse and dynamic study of the vegeta- tion of the Pinus Taeda belt of Virginia and the Carolinas. Bull. Torr. Bot. Club 44° ite te , E. P., Forest pathology in Soseks regulation. U.S. Dept. Agric. Bull. me Pp. Fs 1916 EIR, J.R See suggestions on the control of mistletoe in the national forests of pe pnerescas Forest Quart. 14:567-577. 1916: 4 SanrorpD, F. H., Michigan shifting sands: their control and better utilization. Mich. Agric. Coll. Exp. Sta. Bull. 79. pp. 31. figs. 22. 1916. 1917] CURRENT LITERATURE 349 would have converted into a permanent forest. A neglect of this attention resulted in the complete failure of the project.—Gro. D. FULLER. Nitrogen relations of semi-arid soils —McBrtu® finds that semi-arid soils fail to nitrify dried blood when it is added in 1 per cent quantities. Under the conditions ammonia accumulates in the soil and 50 per cent of the nitrogen may be lost to the air (probably as ammonia) within 6 weeks. When added at ordinary fertilizer rates nitrification is complete. With green manures, espe- cially legumes, nitrification is rapid. Fifty per cent of the nitrogen of the green manure is transformed to nitrates in 30 days. Furrow irrigation leads to the accumulation of the larger part of the nitrate in the surface 6 inches of the soil, and this often results in niter spots. Overhead or basin irrigation gives far better results. Mottled orange leaves show higher water content than checks, and extreme mottling is often, yet not invariably, associated with high nitrate content.—Wwa. CROCKER. Effect of dust on photosynthesis.—The effect of surface films and dusts on physiological processes in plants has aroused considerable interest in recent years. California citrus vegetation in the neighborhood of cement works this fact to determine the effect of dusts on rathohydrate synthesis. He found that the cement dust in some cases shuts out as much as 80 per cent, of the light - from the upper surface of the leaf, but this high exclusion of light did not interfere with carbohydrate synthesis. This work bears out in a practical and interesting way that of Brown and EscomseE in showing the small amount of light that is really necessary for carbohydrate synthesis.—Cuas. O. APPLEMAN. Nitrogen fixation—The question of nitrogen fixation by filamentous fungi has been = thee smb by Duccar and Davis* with reference to Asper- gillus niger, Macrosporium commune, Penicillium digitatum, P. expansum, Glomerella Gossypii, and Phoma Betae. Of these, Phoma Betae was the only form which was definitely shown to be capable of fixing free nitrogen. The quantities fixed by this fungus varied from 3.022 to 7.752 mg. per culture of 5occ. of solution when sugar beet or mangel decoction with added sugar were used as culture media. The authors give a critical review of all the available literature on the subject, and in their own work exercised every pre- caution to avoid the errors and faulty methods which have led to the numerous conflicting results in the investigations of this problem.—H. HAssELBRING. # McBeth, I. G., Relation of the transformation and distribution of soil nitrogen to the nutrition of citrus plants. Jour. Agric. Research 9:183-252. figs. 19. 1917- # Younc, H. D., Studies on the relation of cement dust to citrus vegetation. I. The ack on photosynthesis. Biochem. Bull. 5:95~100. 1916. “4 Duccar, B. M.; and Davis, A. R., Studies in the physiology of the fungi. I. Nitrogen fixation. Ann. Mo. Bot. Gard, 3°413-437- 1916. 350 BOTANICAL GAZETTE [ocroBER Himalayan vegetation—Among the matters of botanical interest STEWART has emphasized is the absence of all luxuriant tropical vegeta- tion from this part of India, the indigenous flora being rather of the desert and scrub types. Perhaps the most interesting thing concerning this little known region is the similarity of the forests on the north side of the mountains to those of the eastern United a as shown by the abundance of trees of such familiar genera as Pinus, a, Abies, Taxus, Juglans, Betula, Ulmus, Prunus, Acer, Quercus, Populus, aa Berberis. Set in strong contrast are the most abundant genera upon the corresponding southern slopes. This aggregation includes Acacia, Capparis, Tamarix, Zizyphus, Melia, Albizzia, and Olea.—Gro. D. FuLiEr. corrhiza of Marattiaceae.—West® has made a careful study of the life history, host relations, and systematic position of a fungus long known to be present in the roots of the Marattiaceae. It is one of the Phycomycetes, and most nearly approaches Phytophthora in such characters as are available, but sexual organs were not observed. West has established a new genus (Stgasporium to include it. No injury to the cells of infected roots by the parasite could be recognized, and the resting spores, with their oily contents, are also formed at the expense of the host. ‘‘The advantage of the association is almost entirely on the side of the fungus, the host plant thriving in spite of the presence of the endophyte.”’—J. M. C Cambium in monocotyledons.—Mrs. ArBER‘ has brought together the i oe Bate 2 red gin f£ 1 ele c Ld 1 hiwm in monocotyledons, and records also some new observations. It is clear that such a cambium occurs more widely among monocotyledons than has been generally supposed. To the previously recorded cases she adds the inflores- cence axes of Eremurus himalaicus and Nothoscordum fragrans, and the young shoots of Asparagus officinalis. The widespread occurrence of this ‘vestigial, intrafascicular cambium” is a strong additional argument in favor of the derivation of monocotyledons from dicotyledons.—J. M. C. Seedling anatomy of Ranales.—Miss BLAcKBURN*® has investigated the seedling anatomy of a large number of the Ranales, chief attention being given to the Ranunculaceae. The results of chief phylogenetic interest are the 43 STEWART, RALPH R. 93 observations on the flora of northwest Himalaya. Torreya 15:21 gabe. Jigs. ‘ #® Wrst Cyrit On Meas Marattiacearum and the mycorrhiza of the Marattiaceae. Ann. Botany 31:77-99. pl. 3. figs. 9. 1917- 47 ARBER, AGNES, On the occurrence of intrafascicular cambium in monocoty- ledons. Ann. Botany 31:41-45. figs. 3. 1917. # BLACKBURN, KaTHLeeN B., On the vascular anatomy of the young epicotyl in some Ranalean forms. Ann. Botany 31:151-180. pl. 13. figs. 19. 1917- s 1917] CURRENT LITERATURE 351 general prevalence of the trilacunar trace in the seedlings, and the almost universal occurrence of a single ring of bundles connected at a very early age by cambium. This interfascicular cambium is usually absent in the adult stems of the ee anunculaceae, but it is invariably present at some stage in the seedling. The evidence of the origin of herbs from woody plants is increasing.—J. M. C Germination of ascospores.—BRIERLY® has experimented with the ger- mination of the ascospores of Onygena equina, a fungus occurring on decom- posing horns and hoofs of cattle, sheep, etc. The results showed that “ripe” ascospores will germinate directly after a prolonged resting period, and that this period may be curtailed or eliminated by treating the spores with arti- ficial gastric juice, but not by subjection to low temperatures. “The full- grown unripe ascospores and the chlamydospores will germinate immediately in the absence of digestive treatment.” —J. M. C Respiration.—APPLEMAN® has investigated quantitatively the relation of oxidases and catalase to the process of respiration in potatoes. He found that there was no correlation between intensity of respiration and oxidase activity, but that catalase activity of the extracted juice of the potato shows a close correlation with the respiratory activity of the tuber. He considers, therefore, that the oxidases are not the controlling factor in respiratory intensity, at least in potato tubers, whatever réle they may have in connection with biologi- cal oxidations.—Cuaries A. SHULL. History of forest ecology.—In a rather extensive review of the literature of botany and of forestry investigations, BOERKER* has attempted to trace the influence of both upon the development of the new phase of science known as forest ecology or silvics. Perhaps the most important part of the paper is-that in which he traces the ecological principles which were stated by some of the earlier leaders in forestry, but which have received little attention from their fellow foresters. Of almost equal importance is the rather extensive bib- liography.—Gero. D. FULLER. Wandering tapetal nuclei—Prckerr® has described in detail the differ- entiation of the tapetum and its subsequent behavior in Arisaema triphyllum # Brrerty, Witi1am B., Spore germination in Omygena equina Willd. Ann. Botany 31: ja ea 1917. ® AppLEMAN, CHARLES O., Relation of oxidases and catalase to respiration in plants. Amer. Jour. Botany 3:223-233. 1916. * Borrxer, R. H., A historical study of forest ecology; its development in the fields of botany and forestry. Forestry Quarterly 14:380-432. 1916. 8 Pickett, F. L., The wandering tapetal nuclei of Arisaema. Amer. Jour. Bot. 3:461-469. pl. 20. figs. 8. 1916. 352 BOTANICAL GAZETTE [OCTOBER and A. Dracontium. The tapetal cells early show peculiarities of cell wall, cytoplasm, and nucleus. The wall entirely disappears, and the freed proto- plasts form a “periplasm”’ that spreads through the cavity of the sporangium. The forms assumed by the tapetal nuclei, as well as their peculiarities of struc- ture Jesse the possibility of “active migration among the developing pollen spores.”—J. M. C. Vermont trees.—One of the most recent additions to the rather large series of tree manuals is from Vermont. It closely resembles that from Michigan previously reviewed,54 but it has been revised and modified to meet the slightly different conditions in the new region. There are two sets of keys, one for winter and another for summer use. These, together with the illustrations, should make the identification of any tree an easy matter.— Gro. D. FULLER. Fossil Sequoia from Japan.—Miss Yasut has*s described a new species of Sequoia (S. hondoensis) from a coal field of Japan belonging to the Tertiary. The genus was recognized, not only by its normal structural features, but also by characteristic wound reactions. This discovery adds to the evidence of the wide distribution of Sequoia during the Tertiary, and also adds testimony to e assertion that Sequoia has descended from the Pityoxylon type.—J. M C. The vegetation of New York State—Brays has compiled a useful description of the vegetation of New York State, seen from the viewpoint of an ecologist. The state is divided into zones according to MERRIAM’s system, a map showing the modifications of the zones resulting from differences in altitude and the changes due to soil and to proximity to the Great Lakes is produced. The various forest types are well described.—Gero. D. FULLER. Anatomy of epiphytic orchids—Curtis*’ has published a detailed account of the anatomy of 6 epiphytic orchids from New Zealand. Considerable varia- tion is shown in the extent and distribution of the different tissues, and the paper is full of data that will be useful when the anatomy of orchids comes to be organized.—J. M. C. ss Burns, G. P., and Oris, C. H., The trees of Vermont. Vt. Agric. Exp. Sta. Bull. 194. oe 244. pls. 90. 1916. 54 Bot. Gaz. 57:77. 1914. ss Yasut, Kono, A ~— wood of Sequoia from the Tertiary of Japan. Ann. Botany 31: 101-106. fl. 4. 1917. % Bray, W. L., The aan of the vegetation at jae York State. N.Y. State Coll. Tema: Syracuse Univ. Publ. 3:pp. 186. figs. 52. 1915. s7 Curtis, K. M., The anatomy of 6 -— species of the New Zealand i Ann, Hoteny 31:133-149. pls. 7-12. 1917 VOLUME LXIV NUMBER 5 14k BOTANICAL GAZETTE NOVEMBER 1917 FOOTHILLS VEGETATION IN THE COLORADO FRONT RANGE CONTRIBUTION FROM THE HULL BOTANICAL LABORATORY 237 ARTHUR G. VESTAL (WITH EIGHT FIGURES) The coniferous forests of the Rocky Mountains are fairly well known; the other plant associations have been little studied. In the present account descriptions are given of typical representations of the plant communities of the foothills zone. The area is confined to the eastern slope of the Rockies in Colorado. By the foothills zone is meant the lower elevations, from the plains at 5000-6000 ft. to the middle slopes at 7500-8000 ft. The vegetation zones of the Colorado mountains have been characterized by RAMALEY (10). A large part of the field study has.been made in the area just west of Boulder, during three years’ residence at the University of Colorado; the other parts of the region have been studied on numerous visits, chiefly to stations at or near the mountain-front, from the Big Thompson River as far south as Raton, New Mexico. This article is the second of a series dealing with the vegetation and plant geography of the eastern mountain-front in Colorado. The first account (24) is of the plains and prairie associations of the region. The writer is indebted to Professor FRANCIS RAMALEY for many kindnesses and for help in different ways. Grassland in the Rocky Mountains has a much more important réle than is usually accredited to it, particularly in the lower slopes. 353 354 BOTANICAL GAZETTE [NOVEMBER It is perhaps the conspicuousness of the trees, especially in distant views and in profiles of slopes (fig. 8), which gives the common but not wholly true impression that the foothills are generally forested with conifers. The rock pine, the most generally distributed conifer of the region, forms relatively few and scattered true forests; it usually grows in very open formation, in mixture with the grassland which covers most of the surface. The general aspect of the vege- tation is that of an open growth of grassland and scattered pines over a dry and partly bare upland of granitic hills. Semi-meso- phytic and phytic communities, of both herbaceous and woody plants, occur; but only locally, in moister or more sheltered ravines and canyon-bottoms. The vegetation complex of the mountain- front is a modification of that of the foothills, but is less simple in’ composition. Environmental conditions The Front Range in Colorado is an up-arched and dissected plateau of crystalline rocks, the tops of most of the hills forming the remains of a peneplaned surface; scattered higher mountains represent monadnocks surmounting the former general level. The eastern part of the plateau slopes gently toward the plains, the sedimentary strata of which are here upturned against the granitic rocks, forming sloping crags on the outer face of the foothills, or hogback ridges separated from the hills by north-south valleys. The physical geography of the Front Range is described by DAvIS (5). Itis with the lower, more easterly part of the granitic plateau and with the more irregular country of the mountain-front that this study has to do. The climate of the foothill region is dry, though not enough so to be called semi-arid, like that of the plains. Rainfall at the mountain-front is from about 15 to 18 inches average for the year; higher in the northern part of the state and onthe elevated Platte- Arkansas divide, lower south of the Arkansas River. The upper foothills receive about 18-20 inches. Annual variation of rainfall is considerable. Most of the rain comes during the growing season. At Boulder, and in the northern foothills generally, April and May are the rainiest months; in the southern foothills the earlier part of the summer is drier than later. This, with higher summer ». BORD cs a? VESTAL—FOOTHILLS VEGETATION 355 temperatures and probably greater insolation, gives a drier aspect to the southern foothills; pinyons are abundant, instead of rock pine, as in the northern part of the state. Mean annual tempera- tures in the foothills vary from 40 to 50° F.; mean summer tem- peratures 60 to 70° (ROBBINS 17). Evaporating power of the air is great, though much less than on the plains. Local variations in atmospheric conditions, due to surface configuration, are con- siderable. Insolation is much greater on summits and south-facing slopes than on north-facing slopes or in ravines. The drying winds are usually from the west, and their effects are greatest on summits and the flatter uplands. Local and topographic factors are extremely and very locally variable. Position with reference to surroundings, and slope, its amount and direction, may perhaps be called the two master factors of the topographic complex. Slope and position are most important in determining conditions of soil deposition or removal (consequently depth and texture of the soil); conditions of absorp- tion and run-off, drainage, or seepage from above, or possible seepage from snowdrifts; presence or absence of plant remains, which may contribute humus, or locally form a mulch (pine needles) ; and conditions of exposure to sun and wind with its attendant effects. The granitic hills in general (fig. 1) are in an early-mature Stage of topographic development (for a mountain region of resistant rocks); the side-slope profiles are nearly straight, with comparatively little detritus covering the bottom of slopes; the tops of the hills are usually rounded, and hardly more subject to erosion than the sides. In general, the foothills are so well drained that bogs, marshy flats, and moist-soil meadow areas are infrequent, even in canyon-bottoms. Hilltops and side-slopes are covered, usually thinly, with rock-débris or with decomposed granite soils, varying in texture from coarse gravelly material of angular frag- ments’ to fine black loamy humus. Wide dikes and occasional outcrops of more resistant rock have only a little soil, in joints and crevices, hardly any elsewhere. * The writer has not been able to find a distinctive name for this coarse angular débris resulting from decomposition of granite; it is not re & Os tone Ce word usually implies; in this article it will be called “ te-gravel.” 356 BOTANICAL GAZETTE [NOVEMBER Texture of soil in its influence on water relations is probably the most important soil factor in the foothills, so far as local distribu- tion of plants is concerned. Especially interesting are some of the features of mixed soils, in which fragments of greatly different sizes are intermingled. Rocks of all sizes may occur on the surface, or buried among finer fragments as rock-débris of detrital slopes. Where the large fragments are imbedded beneath the surface in fine soil, the water content of the latter appears to be increased. 1,.—General view in foothills, looking westward to snowy range-crest; fore- Fic ground a eh slope; general vegetation grassland with scattered pines; southwest of Boulder, 7200 ft. Where the large rocks are exposed at the surface, moisture condi- tions appear to be more favorable immediately beside and under them, so that comparatively mesophytic plants are seen growing in mixture with xerophytes, the former always growing beside or from under the surface rocks. This effect will be noticed in the lists of species; many plants are found in both xerophytic and mesophytic assemblages. The more frequently recurring combinations of topographic and atmospheric factors which form effectively different local environ- ments for plants may be viewed in the synopsis which follows. It is intended to apply only to the foothills proper; a number ol situations of the mountain-front belt cannot be included herein. 1917] VESTAL—FOOTHILLS VEGETATION . 357 CLASSIFICATION OF FOOTHILLS HABITATS Xerophytic neg (the general condition of summits and side-slopes) Rocky habita Craggy pe and rock-walls (see figs. 2, 3) Rock-strewn detritus slopes Rock-talus, usually less stable than preceding “Granite-gravel” habitats Compacted granite-gravel floors and side-slopes (see fig. 3) Loose granite-gravel floors, washes, and talus (= gravel slides) Fine-soil habitats ed-soil floors and detritus-slopes (fine soil with imbedded and superficial rock fragments of various sizes) Fine-soil floors and detritus-slopes (infrequent) Less xerophytic habitats (valleys and steep slopes, etc., relatively local) Less xerophytic side-slopes coined? north-facing, cantly of considerable gradient, and best developed in valleys) Mesophytic ravine habitats Narrow ravines (best developed in small side-canyons, especially on the south side of eastward-flowing main streams) Canyon-bottoms (the wider bottoms of the larger canyons are sometimes, however, exposed and xerophytic) Seepage and dripping areas (infrequent and small) Stream-side habitats (with usually constant supply of soil moisture, but widely varying atmospheric conditions Synopsis of plant associations The following synopsis is aimed to give in perspective the distinguishing characters of the plant communities of the foothill region. It is based upon whatever features of the particular com- munity seem most distinctive and appropriate: growth-form, moisture relations, physiographic, geographic, and successional relations. CLASSIFICATION OF FOOTHILLS ASSOCIATIONS iations generally primitive in character: the first vegetation of new or adivoubic & habitats, usually in rocky or gravelly situations; vegetation open and sparse, generally xerophytic Plants lichens; on rock surfaces, either on craggy summits, knobs, and rock-walls, or on loose boulders......-......0.00¢e0e Lichen associations Plants paella sticg in rocky or detrital situations, soil of variously ani tg instr shrubs; of nate local and temporary occurrence; frequent in areas recently ieee ae sess, + Sumac association Dominant a Faia bie) punted coercieton 358 BOTANICAL GAZETTE [NOVEMBER Associations generally intermediate or established in character (usually sub- ase to primitive associations, but often in habitats apparently little ed from the primitive condition); soil often of mixed or fine texture, or PRT considerable humus content; vegetation usually less open and sparse than in precedin Typically developed in ean or semi-xerophytic habitats, which are of general occurrence in the foothills region (these associations are conse- quently extensive) ominant plants evergreen trees; usually in rocky or coarse soil Of Seeae an = xerophytic ueneters ee distributed in the OOUHINS TOMI iso pck Bui ed a FUSES ws a e's ock pine association Of Selativey | more xerophytic pharactess of ae Rite (east of the range-crest) more southerly distribution than preceding Pinyon-cedar association Dominant plants deciduous trees or large thicket-forming shrubs; of southerly distribution east of the range-crest; frequent in fine soil, and ranging into less xerophytic habitats.............. Quercus association Dominant plants shrubs Shrubs tall and loosely branched, occurring mostly at and near the mountain-front, in coarse or rocky soils...... Cercocarpus association Shrubs low, Pep and densely branched, occurring mostly in the foo Plants i sere of northerly distribution, more frequent in the hihiet fOCthIS ee eS Arctostaphylos association Plants deciduous, of more a pesca more frequent in the tower Soetn. o6s e k nothus association Dominant plants herbaceous; veuetation grassland, eae mostly of xerophytes Dominant plants including plains short-grasses of surface-rooted habit; lant population large and diverse, Foothills mixed grassland association Dominant plants mostly tufted bunch-grasses of deeper-rooted habit Bunch-grass association Typically developed in mesophytic or semi-mesophytic habitats (which are much less prays in the foothills than xerophytic habitats, being repre- sented chiefly on slopes and in ravines and canyons) Dominant ete evetureen trees... 55 2s sss Pseudotsuga association Dominant plants deciduous trees Typically bier along stream margins in open canyons Populus-Salix stream-side association Typically developed in less exposed situations cate preceding, as bottoms of v-shaped ravines and moist shaded slo Canyon en association — developed in moist ravines or slopes with humus soil; or, 10 the higher foothills, in moist patches of the granite-gravel upland pen association Tgt7]} VESTAL—FOOTHILLS VEGETATION 359 Dénsinant plants shrubs, or rarely reaching tree size Plants larger, comparatively well separated; plant unnosition variable; ranging also into xerophytic habitats Foothiils mixed shrub association Plants smaller, low, closely set, usually in fine moist soil Symphoricar pos association Dominant plants herbaceous. . . . Foothills mesophytic grassland association Descriptions of associations The plant communities are described in the order of their appearance in the foregoing synopsis. They are subject to greater geographic variation than can be treated fully in this article; mention is made, however, of the more considerable variations. The space allotment is not always proportionate to the importance or general interest attaching to the several associations; some are already fairly well known, some are less variable or can be summed up more concisely than others, and some have been less thoroughly or less widely studied. An approach to a balanced treatment has been sought by the use of a smaller type for statements of less general significance, descriptions of minor or very local vegetation divisions, and detailed passages included by way of illustration or amplification. Plant names, when appearing without citation of authorities, may be understood to be as in CoULTER and NELson’s Manual (2), which in general follows the usage recommended by the Vienna Congress. The unit of vege- tation is the plant association, in the generally accepted sense; its distinctive representations, appearances, or variants are spoken of as consocies; the terms as used are described in an earlier article (24, p. 382, footnote). Index letters attached to species names signify frequency or abundance or regularity of occurrence, as follows: a, abundant; f, frequent; 7, infrequent; /, focal or locally; ch, characteristic in the community or situation mention It will be understood that the total number of species of iat occurring in an area so extensive as that of this study is very large. No attempt has been made to work out the complete floristics, or the floristic variation of the several communities as represented in different localities. Field botanists will remember that very many of the species making up the flora of a region are rare, known from a single or very few stations, are in effect of very slight ecological significance, so far as vegetation is concerned. A further consider- able proportion is not found in extensive plant assemblages (as, in this study, grass species occurring only in stream margins), and is not important as part 360 BOTANICAL GAZETTE [NOVEMBER of the vegetation of the general area. Several or numerous species of certain genera, again, may be of similar habitat distribution, so that a species of one locality may be replaced in the same habitat in another locality by a second species of that genus. Care has been taken to select species for the floristic lists which are as representative over a considerable area as may be. In the southern foothills, as in the plains of southern Colorado, many more plants of southwestern derivation enter into the flora, particularly in the primitive grassland and mixed grassland assemblages. Many are true desert plants; a few cacti and chenopods and many composites fall in this group. That this geographic variation from north to south is ecological as well as floristic should be apparent. It is paralleled by a similar altitudinal variation in composition, from the montane zone to the plains. LICHEN ASSOCIATIONS TUuCKERMAN (23); W1xt1AMs (27), lichens in the Black Hills; HERRE (7), lichens of Mount Rose, Nevada; SHANTz (22, p. 187).—Fig. 2. A considerable proportion of the area of the foothills is exposed rock, and its vegetation, except in crevices, is mostly composed of lichens. The study of lichen vegetation has usually been left to the specialists in that group of plants, since they are so poorly © known to most other botanists. For this reason brief notes on external appearance, as to color and vegetative form, are given with the speciesnames. The writer is indebted to R. HEBER Howe, Jr.,2 who has made the species determinations and examined this part of the manuscript (fig. 2). _ Dry surfaces, much exposed to sun and wind, occupy most of the area of bare rock in the foothills. They slope considerably, so that run-off is rapid and absorption minimal. The first lichens to invade dry rock, forming primitive xerophytic stages of lichen growth, are fine-grained crustose forms, notably the black-gray Rinodina radiata Tuck. (?=R. thysanota Tuck.) and an indetermi- nable lead-gray species which is especially characteristic. Theseare soon followed, but not displaced, by lichens of an intermediate stage, mostly coarser crustose forms; the gray-green Rinodina oreina (Ach.) Wain. is a character species both locally and geogr: aph- ically abundant. The established stage on dry rock is marked by the gray-green small-foliose Lecanora rubina (Vill.) Wain. and the 2 Some of the crustose species were determined for Dr. Howe by H. E. Hasse; the Stereocaulon by L. W. Ruwwpte. € 1917] VESTAL—FOOTHILLS VEGETATION 361 larger-foliose, also gray-green, Parmelia conspersa (Ehrh.) Ach., which may be said to be the dominant and most frequent lichen of exposed rock. Here also occur the gray-green crustose-foliose Rhizocar pon geographicum (L.) DC., with Rinodina oreina persisting from the preceding stage, and a few other species, including one or two of Parmelia, Gyrophora erosa, and the large and peculiar Gyrophora vellea (L.) Ach., in crisped-margined dirty-gray plates ©.25-2 inches in diameter, attached centrally beneath. These Fic. 2.—Lichens on steep rock-wall of rather sheltered side-canyon opening north- ward into Boulder canyon; dark masses at joints are cushions of Selaginella. established stages appear to be self-perpetuating so long as physical conditions of dry rock are unchanged. Less exposed, but usually dry, surfaces, such as shaded rocks, overhangs, surfaces dripping for some time after rains, recesses in joints, etc., hav characteristic lichen assemblages and definite successions. The earlier lichens include the yellow-green crustose Acarospora xanthophana (Nyl.) Fink (charac- teristic and abundant), with Lecanora rubina, Rhizocarpon geographicum, and Rinodina radiata. Acarospora persists in the established stages, which also show the bright orange- sor crustose-foliose Caloplaca elegans (Link.) Th. Fr. (characteristic and abundant), Parmelia conspersa, P. sulcata Tayl., P. conspersa var. stenophylla? Ach., peters vellea, and other species. Considerably less of the rock surface remains uncovered with lichens here than in the xero- phytic situations, and the number of species is larger, although the area of this 362 BOTANICAL GAZETTE [NOVEMBER habitat and its lichen assemblage is very much smaller. Caloplaca elegans and Parmelia sulcata are frequent on scattered rocks and tree trunks in shaded canyon-bottoms. oist surfaces in humid recesses of the rocks show numerous lichen species, mostly foliose, including Physcia aipolia (Ach.) Nyl. and a number of species of Parmelia. osses grow with the lichens abundantly in these situations. These distinctly humid recesses are scattered and infrequent in the foothill region. A Cladonia, probably C. fimbriata (L.) Fr., is characteristic on moist north-facing canyon slopes, amongst mesophytic herbs, or beside surface rocks. A pulvinate, finely divided whitish fruticose lichen, Stereocaulon albicans Th. Fr., has the growth-form of a pulvinate moss, being “rooted” in moist rock crevices, although the aerial part is more or less exposed. It is infrequent. SUMAC ASSOCIATION Rossins (16, p. 46), distribution on Long Mesa near Boulder. As indicated in the synopsis of associations, the shrubs of sumac (Rhus cismontana Greene, which is so like R. glabra of the eastern states as to be considered identical with it by some botanists) often form a new plant assem- blage in denuded xerophytic situations. These are extremely variable, includ- ing old roadways, rock talus below road embankments, quarries, or prospect holes, stony hillsides where erosion or landslipping has removed much of the plant cover, or places which have been burned. In the lower foothills, and at the mountain-front, the sumac appears to be quite common after fires, the slopes being too dry to allow the establishment of aspens, in most places. The shrubs are usually separated, the sparse plant cover of the interspaces often being composed of plants of the primitive grassland association. As developed in the foothills, the assemblage shows no essential difference from the sumac growths of many parts of the United States. In autumn the bright red coloring of the leaves makes the community very conspicuous, so much so as to give an exaggerated notion of its frequence of distribution. FOOTHILLS PRIMITIVE GRASSLAND ASSOCIATION CLEMENTS (1, pp. 9-12), gravel slide formation, half gravel slide formation, in part; RAMALEY (12, pp. 124-128), Cercocarpus scrub, upland dry grass, and foothill sagebrush-grass formations, in part; ScrovEer (21), gravel slide and half gravel slide formations, in part. The principal herbaceous growth of dry coarse-soil situations in the foothills presents very great variability, and is very generally distributed, occupying not only large areas by itself, oa oceutring in mixture with shrubs and trees tion It is perhaps not too much to say that oe a small proportion of 1917] VESTAL—FOOTHILLS VEGETATION . 363 the area in which the rock pine is of frequent occurrence is occupied by actual forest; the usual vegetation of the pine-sprinkled upland is open, the ground-cover is made up of associations of herbaceous plants or low shrubs; prominent among these is the primitive grassland. It enters largely into the ground-cover of other mixed associations also, in which trees and shrubs other than rock pine are conspicuous. The variability of such an open ground-cover as € primitive grassland is so great that no particular set of plants can be said to characterize the whole community, although certain features are common to all of its variants or consocies: (1) they constitute the first vegetation in new and unfavorable habitats; (2) this vegetation is sparse and open; (3) it is made up of an assemblage of species typical of coarse soils and rather considerable exposure to sun and wind, some more commonly in the plains, others in the mountain region (many of these plants are common to several of the consocies, though some few are typical only in the more extreme developments of particular consocies-habitats, as Erigeron compositus in packed granite-gravel); (4) as development of vegetation proceeds in the several consocies, with accumulation of the plant remains, closing of the plant cover, etc., they resemble one another more closely, converging into a less open growth, which may be known as the foothills dry grassland association, the next higher in the genetic series. Many of the species of the primitive grassland seem not to be particularly xerophytic, as Thlaspi coloradense and Gilia aggregata, for these are active during the early part of the season, when the moisture supply is ample. Such plants are very widely distributed in the foothills and are not characteristic of particular habitats nor of the species groupings of particular plant communities. A partial list of species of the primitive grassland follows: SPECIES LIST: PRIMITIVE GRASSLAND Selaginella densa (/) Phlox multiflora Aristida longiseta (/) Gilia a Stipa comata (J) Gilia pinnatifida Bouteloua hirsuta (/) Phacelia a heterophylla (ch) ‘Koeleria cristata (ch) Oreocar Sitanion brevifolium (2) Pentstemon humilis 364 BOTANICAL GAZETTE [NOVEMBER . Arenaria Fendleri Chrysopsis villosa (ch) ora Jamesii (ch) Chrysopsis spp. (ch) Berberis olium Townsendia exscapa Thlaspi shake Townsendia grandiflora Physaria floribunda (/) Machaeranthera aspera Lesquerella montana Helianthus pumilus Sedum stenopetalum (ch) Hymenoxys floribunda (south) Potentilla pennsylvanica strigosa __ Gaillardia aristata Potentilla Hippiana Artemisia frigida (ch) Astragalus Purshii Artemisia gnaphalodes var. (ch) Geranium Parryi (ch) Senecio Nelsonii (ch) Mentzelia spp. The more important representations of the association in special habitats: (1) The mixed consocies of mixed detrital slopes. This term may applied to the very sparse plant community of slopes on which the fragments of rock-débris are of all sizes, and in which as a result conditions for plant life vary extremely locally. The vegetation may be regarded as a mosaic of dif- ferent variants of primitive grassland, with the addition of certain components from other vegetation types, as the lichen, shrub, and pine associations (see figs. 4, 8). (2) The Geranium-Chrysopsis consocies of unstable granite-gravel slopes, in which the loose bunches of these two plants are the most frequent or the only plants in the loose decomposed granite soil. (3) The Artemisia frigida-Koeleria consocies of stony detrital slopes (rock talus, frequently). The habitat is quite common though seldom very exten- sive; the sage may be very abundant without the grass Koeleria; it is an im- portant species in the northern Great Plains and in the mountains up to 10,000 ft. (4) The compacted granite-gravel consocies. Dwarfed plants of Erigeron compositus, Senecio Nelsonii, and a few other species are characteristic in level or gently rolling top surfaces, on which the thin coarse soil has become com- pacted into a hard floor (fig. 3). In its most extreme condition seen, the Erigeron was the only plant, occupying less than 4 per cent of surface. Rather infrequently, Potentilla Hippiana occupies these situations, forming a pure growth which spreads vegetatively. (5) The mat consocies of gravel slides. These habitats are more frequent in the Pike’s Peak highland than in the Front Range proper, where they are This plant has narrow pinnately 5-divided leaves, and appears to be quite sess different from the entire or apically 3-divided form with dense white canescence. With this structural difference is an apparently constant habitat differ- ence; the di lly in very coarse soil, the other i in clay, abundant only at the mountain-front. Itish tk on determine e forms Ges eis Ne eek a eas 1917] VESTAL—FOOTHILLS VEGETATION 365 best developed on south-facing slopes, commonly at the bottoms of open canyons, beside graded roadways. Species of Gilia , Physaria, Phacelia, Berberis, Gaillardia, and Pachylophus are chatactetiatic Gravel slides have been studied by CLEMENTS, and by SCHNEWDER (21) The primitive grassland is closely related to certain associations of the Plains region, notably the mat association (9, D: 396; 34, Pp: 393), and the Gutierrezia-Artemisia association (24, p. 398), and to the other primitive assemblages leading to short-grass. ‘It is more generally distributed, as would be expected, at lower elevations 1G. 3.—Granite-gravel floor, with much bare surface, some primitive grassland, and mats * A rctosta A ylos; in background rocky summit or knob, with scattered pines; Flagstaff Mounta: and more southerly parts of the mountain region, and in the more exposed habitats. It probably occupies a larger proportion of the total area in the lower parts of the Front Range than any of the other associations in their unmixed condition. ROCK PINE ASSOCIATION CLEeMENTs (1); RAMALEY (10, 12, 14); Ropsrns and Dopps (18), distribu- tion of conifers on the mesas near Boulder; SHAntz (22, p. 184); WATSON (25, p. 207); Youne (28, p. 337)- Pinus scopulorum, variously called the rock, western yellow, or bull pine, is the important tree in the foothills. Its plasticity 366 BOTANICAL GAZETTE [NOVEMBER is remarkable, growing in all kinds of soil, on slopes of every angle and every direction, through wide variations in soil moisture, evaporation, light, and temperature. Its wide geographic and altitudinal range is an expression of this plasticity. In favorable situations it grows rapidly, with straight trunk and branches regularly arranged; in the more exposed places it is reduced in size, and commonly gnarled and irregular. Distribution of the pines is largely a matter of establishment, since the critical stages are seed burial, germination, and the young seedling period. Crevices and soil-filled spaces between rocks, usually of small area, afford lodging places for the seeds; exposed summits and slopes of fine soil are mostly covered with grassland. Small areas of soil deposition may allow burial of many seeds, and consequent development of dense young stands. Seeds germinate well in the tangled mats of Ceanothus Fendleri (see -under Ceanothus association). The first few years of the seedling are safely passed only when several favor- able seasons are successive (at least in exposed situations), as shown by RAMALEY (13, p. 30) for the high mesas near Boulder. According as establishment is abundant or very sparse in a given station, the growth is closed, giving a true pine forest, or scattered, . resulting in the well known open or parklike appearance; this is a mixed vegetation of which the pines form only one component. They may later dominate the whole area if new pines can germinate beneath, but on the whole the closed pine forest is relatively infre- quent. Just how important an influence in the foothills fire has been, and is, is very difficult to determine; it is said by some residents that the whole region just north of Boulder Creek was once much more extensively forested than now; but if fire is of fairly frequent occurrence in a region, it is an environmental factor to be taken into account. Its effect is wholly favorable to the grasslands and primitive growths, at the expense of the pines (fig. 4). In the lower and more southerly parts of the foothills, dry grassland and particularly primitive grassland form the ground cover in most areas of scattered pines. The spiny shrub Ceanothus Fendleri is also commonly seen between the trees. Away from the individual trees, and often even at their very bases, the plant cover is mostly not different from its condition where 1917] VESTAL—FOOTHILLS VEGETATION 367 there are no pines. The trees frequently do modify conditions of growth for ground plants, however, where pine needles accumulate, but this effect is very local. Farther up, and to the north, and apparently more closely associated with pine growths, the bearberry (see under Arctostaphylos association) is an sees part of the ground-cover between scattered trees niperus scopulorum is an infrequent though Scully conspicuous tree alas found with the pines. Pseudotsuga mucronata also mixes in to some extent, even in a few fairly xerophytic stations. Juniperus communis sibirica is a ground shrub of infrequent occurrence. Pinus flexilis is very locally represented, although not confined to the foothills. Pinus Murrayana, the se 4.—Shallow ravine head; mostly grassland, with fine soil at bottom, and thinn rae rockier soil on side-slopes; in coarse soil are numerous pines and Arcto- stephylis (foreground); in middle ground a considerable reat of Prunus demissa (leafless condition), occupying soil moist from seepage; April 1 lodgepole pine, of the montane zone, mixes with the rock pine in the upper foothills. The rock pine is by no means absent from the montane zone, and is even quite abundant there if the lodgepole is absent, as in the Pike’s Peak highland generally. e ae association in its unmixed form (practically closed forest) has very few o spaces. Natural pruning of the lower branches is general. Old needles strew ibe ground; the light is much reduced; the two influences, mulc and shade, acting together or singly, exclude practically all ground plants from the closest stands, and all but a few from less dense forests. ants of primitive grassland very seldom persist in shac Relics of former vegetation are seen in less advanced stages, including acted plants of Opuntia, Cercocar pus, 368 BOTANICAL GAZETTE [NOVEMBER bunch-grasses, and others. A few species commonly found in the undergrowth of unmixed but not densely shaded forest are Harbouria trachypleura, Aletes acaulis, Senecio (one or two spp.), Solidago (several spp.), and Pentstemon humilis. . PINYON-CEDAR ASSOCIATION CLEMENTS (1, p. 8), foothill woodland formation; SHANTZ (22, p. 184); WATSON (25, pp. 205-207), cedar and pinyon formations. The pinyon, or nut pine, Pinus edulis, and less abundantly the cedar of the southern Rockies, Juniperus monosperma, are conspicu- ous plants in the mountain-front of the southern part of the state and in the adjoining foothills. Toward the south conditions are generally more xerophytic at the mountain-front; there the rock pines are common only in higher elevations; they are replaced below by the pinyon. Like the rock pines farther north, the pinyons show local extension eastward into the plains, in rocky habitats, such as the canyon-walls of mck outcrops, and the bluff-crests of the plains stream valleys. Between the trees are plains or semi-desert plants, many southerly species being present which are rare or absent farther north than about Colorado Springs. One of the most notable of these is the candlestick cactus, Opuntia arborescens, common at the mountain-front on rock-strewn slopes and mesas. The pinyons (and to a smaller extent the cedars) are typically broadly rounded, the diameter of the crown being usually as great as the height of the tree, which is rarely more than 12-15 ft. The trees are usually separated so that the crowns are distant from each other by a diameter or a little less, in the closer stands. The writer has never seen a really closed pinyon forest in which the crowns would form a continuous canopy. The interval between trees rically developed. Where the habitat is extensive, the pinyons are quite uniformly dotted over the general area. On rocky ridges and mesa-crests the trees are in ragged lines, in small clumps, or irregularly scattered. QUERCUS ASSOCIATION — LEMENTS (1, p. 6) and SHANTz (22, p. 179), foothill thicket formation, in part; WATSON (25, pp. 207-210), white oaks in the yellow pine association. East of the range-crest oaks may be seen nearly as far north as Denver; however, they form more extensive growths to the south- ward. North of the Platte-Arkansas divide they are perhaps more abundant at the mountain-front and in the Plum and Cherry Creek 1917] VESTAL—FOOTHILLS VEGETATION 369 valleys than in the foothills proper; they range into finer soils than do the pines. In the foothills as well as at the mountain-front the oaks may share mixed rocky slopes with local representations of Cercocarpus, pinyon, rock pine, or grassland associations, or may alternate with them. The extent to which they replace the rock pine on south-facing foothill slopes is appreciable even north of Perry Park, and is increasingly considerable southward. There is no apparent reason why they would not grow north of their —Alternation of mixed pms and oak forest, west of Castle Rock, July rox “tall herbs conspicuous at bor present limits in the mountain-front; some of them extend north on the west side of the range-crest even into Wyoming (fig. 5). e taxonomic condition of these oaks is one of confusion. RYDBERG’s Flora of Colorado (19) lists 11 species, all occurring at or near the eastern mountain-front. Quercus Fendleri appears to be distinct, much more xero- phytic, more southerly in distribution. The intergradations with most of the others are such that specific determinations are very difficult. CLEMENTS mentions Quercus Gunnisonii as the chief species of the Manitou vicinity. Certain Colorado botanists now speak of the doubtful oaks collectively, for the present, simply as Quercus spp. The writer has thus far not been able to distinguish different habitat groups within these Quercus spp. (cf. SHANTZ, 22, P. 179). 37° BOTANICAL GAZETTE [NOVEMBER So many of the oaks do not reach tree size that the assemblage in many places presents the appearance of chaparral. As might be expected from their wide range of habitat-tolerance, they vary considerably in appearance, from shrubby scattered trees or stunted thickets, to low forest with mesophytic undergrowth. In very favorable stations, as along streams in the southern foothills, the oaks may reach a height of 20 ft. and more. The undergrowth in ungrazed parts of the oak scrub has a decidedly mesophytic stamp during the moister part of the season; Pulsatilla, Castilleja, Monarda, Calochortus, Lupinus, Geranium, Galium boreale, Campanula, Thermopsis, Danthonia, Pentstemon unilateralis, are typical of oak borders and less densely shaded parts within. Dense closed shaded oak scrub shows abundance of a tall white- flowered umbellifer, Ligusticum Porteri (?).4 Late summer shows many of the less xerophytic composites, including species of Aster, Solidago, Erigeron, and Brickellia grandiflora var. minor. The undisturbed clumps of small oak trees, where these alternate with dry grassland, are often bordered with tall, rather mesophytic herbs, as Lupinus argenteus, Monarda spp., and Achillea millefolium L. (A. lanulosa Nutt.), as may be seen in fig. 5, taken west of Castle Rock. Low scrubby oak thickets, in grazed areas, are mostly impenetrable to horses and cattle; they are, however, eaten from the outside, and the patches thus slowly reduced in area. This results in a complete replacement of oak by grassland, as stated by SHANTz (22, pp. 182, 203). When, however, the height of the small trunks in the middle of a clump becomes too great for the animals to reach the top leaves, their safety is assured. In these taller growths the lower parts of the trees are much less dense; if there is no outer border of dense thicket, grazing animals are enabled to enter; the assemblage is now 4 scrubby forest of low trees, with open spaces between the trunks and very scanty undergrowth, as in fig. 6. Grazing animals may thus have a large part in determining the character and distribution of the oak vegetation. CERCOCARPUS ASSOCIATION CLEMENTS (r, p. 6) and SHANTz (22, p. 179), foothill thicket formation, in rt; RAMALEY (12, pp. 124-126), Cercocarpus shrub formation; pace (15), local distribution in a square mile of rock Siee and foothills; SCHNEIDER (21, p. 292), thicket of south slopes, in part. Ragged shrubs of Cercocarpus parvifolius, or, as it is called, mountain mahogany, form a characteristic vegetation in dry exposed rocky places, particularly along the mountain-front, on butte-slopes, hogback ridges, stony mesa-crests; in the foothills it is most abundant on south-facing side-slopes, or on the outermost slopes facing eastward on the plains. The stony fragments of the 4 Either L. Porteri C. and R., or L. affine A. Nels., as determined by E. E. SHERFF. 1917] VESTAL—FOOTHILLS VEGETATION 371 soil vary from those of coarse granite-gravel to the variously sized blocks of rock talus. The shrubs are 2-5 ft. high, very loose in habit, with few branches and reduced leaf surface. The fruits are provided with long plumed awns. e plants are separated, being regularly spaced like the pinyons, the intervals likewise varying with degree of exposure. The habitat relations of Cercocarpus are in fact quite like those of the pinyon, and it is north of the pinyon area that the mountain mahogany association is best developed. The interspaces Fic. 6.—Open grove aspect of oak assemblage, caused by entrance of grazing animals, ca Park; open mixed grassland in coarse soil occupies foreground. between plants may be almost bare, or may be occupied by a sparse growth of xerophytes, most of them plains plants or representatives of the primitive grassland, the mat growth-form being common ARCTOSTAPHYLOS ASSOCIATION Cow Les (3, p. 367) and Gates (6, p.-306), Lake Michigan dunes; Wuit- FORD (26, p. 298), northern Michigan. In the Colorado foothills: RoBBins (16, p. 44); SCHNEIDER (21, p. 299); SHANTZ (22, p. 186). The Arctostaphylos-Juniperus association of the northeastern coniferous forest region is very well known to students of vegetation. Practically the same community is represented in the Rocky Moun- tains, associated there as elsewhere with coniferous vegetation. The same plant species and the same creeping habit are seen. The 372 BOTANICAL GAZETTE [NOVEMBER important difference, as seen in the Front Range foothills, is that the juniper is very infrequently seen, the Arctostaphylos mostly dominating alone. Conditions of soil-moisture, soil-texture, position, slope, and exposure are varied. The creeping mats of bearberry are seen on rock, in gravelly shaded and sunny, and through a considerable range in altitude. The growth is more extensive and more frequent, however, away from the mountain-front, at elevations 800-1200 ft. above the lower limit of rock pine, being increasingly abundant from that height upward, and being perhaps more typical of montane than of foothills vegetation. Its most frequent habitat in the foothills is the rolling floor of the granitic upland, the soil of which is thin, coarse, mostly compacted (granite-gravel). Here the conspicuous vegetation is rock pine, in open array of scattered clumps and single trees. Parts of the treeless surface are occupied by large mats of Arctostaphylos, with admixture of Ceano- thus Fendleri (less of this upward); the rest of the area is bare or nearly so, with a few scattered herbaceous plants, mostly of primitive grassland. CEANOTHUS ASSOCIATION RosBIns (16, p. 41); WATSON (25, p. 207). _ Thespiny shrub, Ceanothus Fendleri, is ecologically similar to Arctostaphylos in many respects. It forms a low, matlike, spreading ground cover, and occurs to some extent in mixture with bearberry mats. It differs from the other in being typical of more exposed and xerophytic slopes, in being abundant at lower eh and more southerly in geographic distribution. M1iarp S. MarkLE informs the writer that the Ceanothus community is important in the Sandia Mountains of New Mexico, occurring frequently with the oaks and with Robinia neo-mexicana. Ceanothus ranges into dry fine-soiled habitats more frequently than Arcieslotiedes: and is closely associated with grassland, rather than pine forest. It is not evergreen. : Ceanothus shrubs occur in closely set or scattered patches, mostly in unstable gravelly or finer soil of detrital slopes. They have a strongly accelera- tive part in vegetation-development. Their numerous twigs and thorns, even in the leafless winter condition, catch and hold wind-blown and washed-down soil particles and bits of plant débris, thus stabilizing and adding to the soil, and accumulating humus. In one station this had even resulted in the building of small dunes of wind-blown dust, of about 8 inches height and 18 inches diameter. Seed burial is favored in these mats, as well as germination. Some of the more mesophytic of the foothills plants are seen growing up through the tangled branches; pine seedlings also germinate in the shelter of Ceanothus, which may thus be an important factor in reforestation. On dry, burnt slopes Ceanothus frequently covers a considerable proportion of surface and, with the Rhus cismontana shrub growth, is an important stage in succession after burns. 1917] VESTAL~—FOOTHILLS VEGETATION 373 Ceanothus mollissimus and what appears to be Ceanothus subsericeus Rydb. occasionally occur with the spiny species, in the less xerophytic stations. Ceanothus velutinus is rare in the lower foothills, but is frequent at higher elevations and farther north. Herbs of the primitive grassland and mixed grassland commonly grow out from between the twigs of Ceanothus Fendleri, and to some extent are seen in the spaces between the mats. FOOTHILLS MIXED GRASSLAND ASSOCIATION CLEMENTS (1), ground-cover in the foothill thicket and pine formations, in part; RAMALEY (12), foothill sagebrush-grass formation; SCHNEIDER (21), half gravel slide formation, and grassland of north slopes; SHANTZ (22), outeloua formation, in part: its modified form at the mountain-front; VESTAL (24, p. 386), Bouteloua mixed consocies, as developed at the mountain-front; WATSON (25, pp. 209, 210), herbaceous ground-cover in the yellow pine asso- ciation, and mountain “meadows.” The mixed grassland association normally develops from primi- tive grassland, one of its important féatures being the establishment of the dominant Bouteloua oligostachya, the grama grass of the plains. It thus differs from the primitive grassland in that (1) the ground cover is less open, though still generally xerophytic; (2) the soil is usually more stable (in most situations a physical cause, rather than the effect, of the more permanent vegetation) ; (3) the soil is more finely broken up, and to it may be added con- siderable humus; and (4) a number of plains, prairie, and foothill species absent or rare in the primitive grassland are established. The assemblage is most heterogeneous, since the many plants include widely diverse ecological, geographic, and floristic types. Extreme xerophytes and relatively mesophytic plants, plants of widely varying growth-form and seasonal relations, of great difference in plasticity to environmental variation, in altitudinal and habitat range, may occur in the same small grassland area. This mixed vegetation is really very closely allied to the modified plains grass- land mentioned as the Bouteloua mixed consocies of the short-grass association (24, p. 386). This is found in the mixed mesa soils of the mountain-front zone eae oui the foothills. The conditions which would result in heterogeneity of th tation are probably similar in the lower foothills to those of = mountain-front; some of these are given in the article cited (24, pp. 381, 82). . So many species occur regularly in the mixed grassland, and the variability in ‘flocistic composition in particular stations is so great, that a selected list ee habitats cannot be 374 BOTANICAL GAZETTE [NOVEMBER given. By way of illustration, however, a list of the plants observed in a particular mixed grassland station may be presented, and this is followed by a list of some other species commonly found in the community, but which happen to have been absent from the station selected. The station is on the east slope, not far from the top, of a hill a little over two miles west of the mountain-front and a little north of Boulder, in section 36,T 2N,R72W. The hill is marked in the Boulder quadrangle of the United States topographic atlas by the altitude of its summit, 7168 ft. The spot studied most in detail is at about 7000 ft.; exposure is considerable, as the slope is even and treeless; drainage is probably quite rapid; the soil coarse, with but little humus; proportion of bare surface about 15 per cent on June 18, when the list was made. All of the plants marked as abundant or frequent occur in practically every square meter of surface. PLANT COMPOSITION OF A TYPICAL MIXED GRASSLAND STATION Bouteloua oligostachya (a) Eriogonum umbellatum (2) Phacelia heterophylla (a) Chrysopsis villosa (?) (a) Senecio oblanceolatus (a) Geranium Parryi (a) Artemisia frigida (a) Aragallus Lambertii (a) ) Ceras se Aragallus albiflorus (//) Stipa comata (/f) Opuntia fumes (2) Oreocarya virgata (7) Artemisia eetiai is var. (i) Astragalus flexuosus (7) Eriocoma cuspidata (7) Mamillaria vivipara (2) Sitanion brevifolium (7) Gaillardia aristata (7) Phlox multiflora (2) Potentilla pennsylvanica strigosa (7) Euphorbia robusta (2) Townsendia grandiflora (7) Allium sp. (2) The order in which the species are listed gives a rough approximation of their relative importance as making up a part of the vegetation, in descending e. The names of plant species elsewhere frequent in the association follow: ADDITIONAL SPECIES FREQUENT IN MIXED GRASSLAND Woodsia oregana Selaginella, two spp. Aristida longiseta Echinocereus viridiflorus Lithospermum multiflorum 1917] Poa Fendleriana Agropyron Smithii Elymus triticoides Leucocrinum montanum Calochortus Gunnisonii Yucca glauca Zygadenus intermedius Comandra pallida Allionia linearis et spp. Pulsatilla hirsutissima Argemone intermedia Corydalis aurea Draba spp. Erysimum asperum Potentilla spp. Astragalus spp. soralea tenuiflora Malvastrum coccineum Viola Nuttallii VESTAL—FOOTHILLS VEGETATION Onosmodium occidentale Pentstemon humilis et spp. Castilleja integra et spp. Campanula rotundifolia Liatris punctata Grindelia squarrosa Chrysopsis spp. Solidago spp. Aster spp. Machaeranthera aspera et spp. Erigeron spp. Ratibida columnaris Helianthus spp. Hymenopappus filifolius Hymenoxys floribunda Artemisia aromatica Artemisia canadensis Senecio plattensis et spp. Senecio spartioides 375 Mentzelia spp. Nothocalais cuspidata As regards distribution of the mixed grassland association in the foothills, it may be said that the primitive grassland is more frequent and occupies areas of greater extent, because of the general instability and rocky character of the sloping surfaces. In the upper foothills mixed grassland is absent from com- pacted soil level or rolling surfaces generally occupied by pine and Arcto- staphylos, etc., but dominates on the more exposed mountain sides, which are treeless. The mixed grassland, like primitive grassland, is subject to a gradual ecological and floristic variation, from the south northward, and from the short- grass of the plains to the montane dry grassland of elevations from 8500 to 10,000 ft. BUNCH-GRASS ASSOCIATION CLeMENTs (1, p. 6), Andropogon, etc.; SCHNEIDER (21), half gravel slide formation, in part; SHANTZ (22, p. 43), Bouteloua hirsuta uta consocies, with Andropogon spp., Atheropogon, etc.; VESTAL (24, pp. 3 388-390), bunch-grass association: photograph and citation to descriptions in other regions; WATSON (25, p. 209), Andropogon, etc. The bunch-grass vegetation of the foothills is quite similar to that of the mountain-front and over the whole prairie region, including most of the same species, but containing in addition other grasses of similar growth-form but of different geographic distribu- tion. With the bunch-grasses are many composites and other 376 BOTANICAL GAZETTE [NOVEMBER plants of the mixed grassland, such as Liatris, Chrysopsis, Eriogo- num ‘alatum, etc. The tufted bunch-grass growth-form is well known; the roots are deep and numerous; the plants are mostly late in flowering; they are active during the whole growing season, depending on a constant moisture supply. The chief habitats in the foothills which satisfy this condition are rocky or very coarse gravelly slopes, exposed and dry at the surface, but with rather more moisture beneath than in most areas of mixed grassland; these situations are consequently rather locally developed only. PRAIRIE BUNCH-GRASSES OCCURRING IN FOOTHILLS Andropogon scoparius (a) Muhlenbergia gracilis (/) Andropogon furcatus (a) Sporobolus heterolepis (//) Hilaria Jamesii (Ji) Atheropogon curtipendulus (/) Sorghastrum nutans (/f) Koeleria cristata (f) OTHER FOOTHILLS PLANTS OF BUNCH-GRASS TYPE Trisetum montanum (/) Agropyron spicatum Festuca confinis (/) Sitanion longifolium Agropyron occidentale (J) (?)Elymus triticoides Hilaria is a southern plant and has not been seen north of about Canyon City. Sorghastrum and Hilaria appear not to extend far into the foothills. Koeleria ranges into many widely varying habitats and is found with many different plant assemblages. This may partly be due to its early ripening (it ‘flowers in June), which may allow it to escape the dryness of the latter part of the season. Most of the plants of the second group bloom in early summer also; they are frequently found in clumps of one species, in rock crevices or coarse so risetum ranges into the montane zone, but not into the plains; it is restricted to moister places than most of the others. Agropyron spicatum is one of the chief dominants of the extensive grassland areas in the northwestern states, in intermontane valleys and the Columbia Basin plains. It too matures early in summer and is dried up the rest of the season. Elymus triticoides is included with some hesitation; it may be more like the grasses of the primitive bunch-grass type (24, p. 307). PSEUDOTSUGA ASSOCIATION CLEMENTS (1, p. 14); SCHNEIDER (21, pp. 299, 300), with list of herbaceous plants; RAMALEY (14, pp. 251, 262); WaTSON (25, p. 211); YOUNG (28, p- 343): The Douglas “spruce,” Pseudotsuga mucronata, is, like the rock pine, one of the most abundant and widely distributed conifers of 1917] VESTAL—FOOTHILLS VEGETATION 377 western North America, but in the foothills of the Front Range in Colorado it is relatively very local in occurrence. It is frequent only on north-facing slopes and in canyons, where the snow lies deep and late. It grows in close stands or as scattered trees (fig. 7). Small trees of Juniperus scopulorum may occur infrequently in the Pseudo- tsuga forest; in unshaded areas with moist soil a few aspens may be found. Arctostaphylos and the prostrate Juniperus communis sibirica, so frequently associated with it, are seen as relics. The moist and sheltered slopes on which Pseudotsuga grows may in its stead be covered by the mesophytic grassland association, and many of its plants occur scattered among the conifers, such as Fics. 7, 8.—Fig. 7, Pseudotsuga association on a north slope; fig. 8, another ot, view, showing prevalence of grassland on side-slopes; trees conspicuous in profiles of distant slopes. Mertensia spp., Campanula rotundifolia, Pulsatilla hirsutissima, Saxifraga rhomboidea, Aster laevis, and one or two small ferns. e rock pine grows well in the moist habitats of the Pseudotsuga, if the young trees can get a start, and so the two species are commonly found in mixture, especially toward the top of canyon-slopes and in other less protected ces, Pseudotsuga can range into the habitats of the pine, where, how- ever, it is usually of less symmetrically spire-shaped form, and with fewer and uneven branches, so that the growth habit resembles that of the pine. POPULIS-SALIX STREAM-SIDE ASSOCIATION RAMALEY (12, p. 127, 14), part of the canyon forest formation; WATSON (25, p. 21), Populus angustifolia society; YouNG (28, pp. 330-33 The poplars and willows of stream-sides form a nearly continuous belt in the wider and more open canyon-bottoms of the foothills. Populus angustifolia, 378 BOTANICAL GAZETTE [NOVEMBER the narrow-leaved cottonwood, is the largest and most frequent species. The willows include Salix irrorata and S. exiguus, forming shrubby clumps; and S. Bebbiana, S. amygdaloides, and S. lasiandra, small trees. The hackberry, Celtis reticulata, is perhaps more typically found scattered along stream-sides in quite exposed places than with other trees. It is also common in such habitats in New Mexico. Certain plants common in the canyon forest are also quite characteristic, in the rather less exposed stream-side situations, replacing the cottonwoods and willows in small areas, or intermingling with them. Such plants are Alnus tenuifolia, Betula fontinalis, Acer Negundo, and the shrubby Cornus stolonifera. Scattered plants of the mixed shrub association are also frequently seen: Bossekia, Ribes, Rosa, Crataegus, Prunus demissa, and others. CANYON FOREST ASSOCIATION RAMALEY (12, p. 127); Younc (28, PP. 333, 335), Alnus-Betula-Corylus assemblage; (/.c., p. 334), Crataegus assemblage, etc.; DANIELS (4, pp. 21, 27)- The canyon forest, which contains many of the deciduous tree species of the foothills, is typically developed in local mesophytic stations, such as the slopes and bottoms of narrow canyons, in which the soil is moist (usually from seepage), and the air compara- tively humid, due to the shade and the shelter from wind. A selected list of species is here given: PLANTS OF FOOTHILLS CANYON FOREST ASSOCIATION Trees Alnus tenuifolia Prunus american Betula fontinalis Prunus demissa (N utt.) Dietr.s (ch) Salix Bebbiana (2) Robinia neomexicana ( Populus tremuloides (i) Acer glabrum (ch) Amelanchier alnifolia (/z) Acer Negundo (/) runus pennsylvanica (ch) Crataegus coloradensis et spp. Shrubs Corylus rostrata (/) Rhus Rydbergii (2) Ribes longiflorum Vitis vulpina (/) Physocarpus Ramaleyi (i) Parthenocissus vitacea (/) Rosa Sayi et spp. Viburnum pauciflorum (/) $ Jones (8, p. 35) fails “‘to see any ground for Netson’s P. melanocarpa, 2 though Nutra. describes his as red-fruited, for we know that this species has red till dead ripe, when it turns black,” 1917} VESTAL—FOOTHILLS VEGETATION 379 Herbs Pteridium aquilinum Fragaria OE et spp. Smilacina stellata (ch) Aralia nudicauli Smilacina amplexicaulis (ch) Viola ade Rydbergii (ch) Stellaria Jamesiana astilleja miniata et s Thalictrum spp. Monarda Ramaleyi et spp. Aquilegia coloradensis Hydrophyllum Fendleri (ch) Delphinium Nelsonii (ch) Galium boreale (ch) Ligusticum Porteri (?) Galium aparine Saxifraga rhomboidea (ch) Galium Vaillantii The canyon forest presents a wide range of variability, according as favorable ground conditions are uniform or interrupted; thus in rocky canyon-bottoms and slopes it is patchy in development. It may merge into, or mingle with, areas of Pseudotsuga, mixed shrub, aspen, Populus-Salix, Quercus, and moist grassland growths. The herbs especially may be no more typical of unmixed meso- phytic deciduous forest than of many other mesophytic habitats. The characteristic plants growing in the shade of large shrubs and trees are Viola, Hydrophyllum, and one or more species of Galiwm. These are abundant in unmixed canyon forest, at least in the northern foothills. Amelanchier is an important component only in the upper foothills and the montane zone, or farther north and west in the Rocky Mountains. Acer glabrum often occurs by itself on north or shaded slopes, the bushy plants 10-15 ft. in height, and in most places considerably separated. Prunus demissa, and several species of Crataegus (mostly C. coloradensis and C. cer- ronis), together or singly, dominate tall thickets or low forests, which may be regarded as transitional cnapbabaniae te mixed shrub and canyon forest associa- tions. In new growths or they are low and scrubby; in other places they form a taller and ‘closed growth, with a lower stratum of mesophytic herbs, and may properly be spoken of as forest. Prunus demissa and Crataegus form relatively much more extensive areas of vegetation in the northern foot- hills and especially along the northern mountain-front than in the southern part of Colorado. Robinia is abundant in the southern third of the foothills area. It ranges into drier habitats, in which it is low and scrubby. The Alnus-Betula consocies has been mentioned as being abundant along mesophytic stream-sides. Corylus is frequent only in such situations, occurring in places alone, in others with Alnus and Betula. The climbers, clematis, Virginia creeper, and grape, are local, and more common in sunny openings. Viburnum is in moist canyon-bottoms of the higher foothills. 380 BOTANICAL GAZETTE [NOVEMBER ASPEN ASSOCIATION RAMALEY (14, p. 251); YOUNG (28, p. 347). Botanists are familiar with the réle of Populus tremuloides in revegetation of burned areas, and it is prominent in the montane zone in Colorado in this capacity. The general area of the lower foothills, however, is too dry for establishment of aspens, and they occur only locally, in ravines even more mesophytic, perhaps, than the ordinary habitat of the canyon forest. Thus in the Boulder area the stations below 7200 ft. in which aspens have been observed in local abundance are very infrequent. Such stations are usually in sheltered ravines with deep humous soil, abundantly moist. The trees in places are large, the undergrowth very mesophytic, with Thalictrum, Heracleum, Castilleja spp., etc., and particularly Aquilegia coerulea. At about 7800 ft. in the same vicinity aspens begin to appear in small clumps on the granite- gravel upland, among more frequent clumps of rock pines. No connection with former fires could here be made out; appearances indicated that perhaps there the aspens might be associated with the moist patches resulting from the tardy disappearance of the deeper snowdrifts of winter. The conspicuous yellow color of the aspens in fall probably tends to exaggerate the popular notion of their frequency of occurrence. MIXED SHRUB ASSOCIATION DANIELS (4, p. 20); RAMALEY (12, p. 127), shrubs of the canyon forest; SHANTZ (22, p. 179), thicket formation, in part; notes on distribution and eco- logical relations of the species; RAMALEY (11); ROBBINS (16); SCHNEIDER (20). The shrub associations of the foothills, like the deciduous tree growths, are generally found in rocky or coarse soil stations with constant moisture supply in the substratum, which is reached by the deep root systems. Local distribution, as in the case of the pines, is probably restricted by unfavorable conditions for germination over a large part of the general area. It has been observed that, on irregular slopes where the distribution of snow in late spring is uneven, the shrubs occupy the moister spots determined by the deeper snow patches. In deep moist soil it is likely that the shrubs are soon succeeded by trees, as has been observed in some stations. The shrub species most commonly found appear in the following selected list. Certain of the canyon forest plants which occur with the shrubs in the less mesophytic stations without attaining tree size are included here also. It is significant that so many of the 1917] VESTAL—FOOTHILLS VEGETATION 381 shrubs, and some of the canyon forest plants, have fleshy fruits, and so may be distributed by birds. PLANTS OF FOOTHILLS MIXED SHRUB ASSOCIATION Ribes saxosum Rosa aro Ribes pumilum Rosa Fendleri Ribes vallicola recone alnifolia (7) Ribes longiflorum (J) Crataegus cerronis Jamesia americana (/) Crataegus coloradensis Holodiscus dumosus (/) Prunus americana (ch) Physocarpus intermedius (/) Prunus demissa (ch) Physocarpus monogynus (/) Robinia neo-mexicana (/) Bossekia deliciosa (f, ch) Rhus trilobata (ch) Rubus strigosus (/) Ceanothus subsericeus Rosa Sayi Amelanchier has been mentioned as being rare in the northern foothills, as may be said also for Holodiscus. The common shrubs of rock-crevice habitats are Jamesia and Ribes pumilum. The yellow-flowered Ribes longiflorum, unlike the others of the genus, is more frequent in deep, moist, fine-grained soil than in rocky or coarse soil. Rubus strigosus is more common in the upper foothills, and in less exposed habitats. It and the roses are smaller than most of the other shrubs. Prunus americana forms low dense thickets in rather exposed places. Robinia is southern. Rhus trilobata ranges into very xero- phytic habitats, and can persist and even establish itself on unstable soil of steep or loose slopes. Although a single species may make up the shrub vege- tation at any one spot, numbers of them occur together in a very large variety of combinations, particularly where the habitat is internally diverse. The shrub association, and consequently have been separated from it. relation of the mixed shrub association to the canyon forest has already been mentioned; the two grade into each other, but in the main they are quite Where the shrubs grow close together, a mesophytic undergrowth of herbs develops. Galium aparine or G. Vaillantii, Delphinium Nelsonii, and Viola canadensis Rydbergii are frequent species. The border of many shrub areas, where there is no grazing, shows tall herbs, as Lupinus, Achillea, Monarda, Pentstemon unilateralis, etc. Surface rocks, where present in grassland, may allow the scattering admixture of a shrub element, or even, where the soil is sufficiently moist, invasion of shrubs over the general area. 382 BOTANICAL GAZETTE [NOVEMBER SYMPHORICARPOS ASSOCIATION Y (12, pp. 127, 128); RoBBINs (16, p. 38). The Symphoricarpos association is best iad in moist, fine-grained soil; best seen, in the foothills, on basal or other deep-soiled detrital slopes, clay or loam, with or without humus. The common species of the Colorado foothills is Symphoricarpos occidentalis. The bushes are low, are spaced very close together, and are profusely branched, giving the whole growth a very compact and uniformly dense structure, especially where subject to grazing, as in many stations. From its habitat relations, the bush honeysuckle, as it may be called (it is known in some localities as buckbrush), adjoins a semi-meso- phytic grassland in most places, competing and alternating sharply with it. Many of the taller mesophytic herbs are seen at the border, including Frasera speciosa, Thermopsis divaricarpa, the others already mentioned as bordering canyon forest and mixed shrub, and frequently the tall grass Stipa viridula. This border condition is best seen where the Symphoricarpos assemblage occupies a depression. The shrub area is dominated by the one species, although bushes of Rosa arkansana are mixed in, abundantly in places, and Berberis aquifolia may also be seen. A few herbs may occur underneath. Symphoricarpos in places forms a border between mixed shrub or canyon forest vegetation and grassland. MESOPHYTIC GRASSLAND ASSOCIATION RAMALEY (12, p. 129), meadow formation. There are several kinds of herbaceous vegetation in the foothills, of meso- phytic or semi-mesophytic character, which may for convenience be considered together. There is a meadow growth, which shades more or less completely into the western prairie-grass of the mountain-front (24, p. 390), on the one hand, and into the forest border and forest undergrowth assemblages on the other. On certain shaded ravine slopes a mixture of mesophytic herbs from several of these assemblages has been observed, apparently independent of any tree canopy. The trees affect the herbs, apparently, mainly or wholly by their modification of physical conditions. A selected list of mesophytic and semi- mesophytic species may be given: MESOPHYTIC AND SEMI-MESOPHYTIC HERBS OF FOOTHILLS Stipa viridula (ch) Gentiana affinis Danthonia Parryi (f) Frasera speciosa (ch) Poa pratensis Mertensia ciliata ‘oa Buckleyana Mertensia lanceola Agropyrum violaceum Monarda canner (ch) 1917] VESTAL—FOOTHILLS VEGETATION 383 Calochortus Gunnisonii Pentstemon humilis (/a) Zygadenus intermedius (ch) - Pentstemon unilateralis Iris missouriensis (/2) Castilleja linariaefolia (ch) ‘ Claytonia virginiana Castilleja sulphurea Cerastium arvense (ch) Orthocarpus luteus Delphinium Nelsonii (ch) Galium boreale (ch Thlaspi coloradense (?) Ca eo. recer rotundifolia Erysimum Wheeleri (ch) Aster laevi Saxifraga rhomboidea (ch) Erigeron fee Potentilla pennsylvanica strigosa (ch) Achillea millefolium Thermopsis divaricarpa (ch) Arnica cordifoli rni ca fulgens (/a Senecio integerrimus (/a) © pa | wm ® =) wn ca. Viola canadensis Rydbergii The prairie grass aspect has already been mentioned, and a description cited. The foothill meadow assemblage in early summer typically shows such conspicuous plants as Delphinium, Cerastium, Arnica, Senecio, and sag linariaefolia (C. sulphurea is frequent only in the higher eleva- ons). The mixed shrub association frequently alternates with meadow, and eck upon it, and is bordered by the taller herbs with that assemblage. The forest border and forest undergrowth communities have also been mentioned. oist rock crevices in sheltered ravines become overgrown with cushions of Selaginella (fig. 2) and smaller cushions of mosses; humus accumulates by the growth and death of these plants; in this Seiinias rhomboidea and later other herbaceous or woody plants may become established. This is a very common successional series from oad rock in mesophytic habitats. Herbaceo eous plants commonly seen scattered along the moist soil of stream margins, in open dauae include Rumex sp., Heracleum lanatum, Thermopsis, and Lupinus, with certain grasses, as Muhlenbergia racemosa, Eatonia obtu- Sata, etc. Hygrophilous and amphibious ‘Plants of the canyon streams may for convenience be mentioned at this point. Marchantia polymorpha is found on a very few stream —- on ‘ie: or in crevices in sheltered spots. Many mosses may accompany it, especially where some soil accumulates in cracks of stream-side boulders, etc. Dodecatheon radicatum may here be found, or species of Ranunculus in boggy places. A number of species are seen in these very restricted boggy places. Mimulus Langsdorfii and Veronica americana may grow there or in quiet little pools of the stream itself. RaMALEY has given these growths the name Stream Bank Marsh Society (2, p. 227). Eastern Intivors STATE NorMAL SCHOOL CHARLESTON, 384 BOTANICAL GAZETTE [NOVEMBER LITERATURE CITED 1. CLEMENTS, F. E., oT and succession herbaria. Univ. Neb. Studies 4:329-355. 190. . CouLTER, J. M., and Necoak 7 ats manual of botany of the Central, Rocky Mountains New York. - Cowtes, H. C., The ‘sage acid of the sand dunes of Lake Michigan. Bor. Gaz. 27:95, 167, 281, 361. 1899. 4. DAntets, F. P., The flora of apa Colorado, and vicinity. Univ. Mo. Studies 2 (Sthenice Series): no. 2; pp. xiv+31I. IgII. 5. Davis, W. M., The Colorado Foc Raee Ann. Ass. Am. Geog. 1: 21-83. IQIt. GatTEs, F. C., The Nisiceeae of the beach area in northeastern Illinois and southeastern Wiscon: Bull. Ill. State Lab. Nat. Hist. 9:251-372- 1912. Herre, A. W. C. T., "The lichens of Mount Rose, Nevada. Bor. Gaz 55°392-396. 1913. 8. Jones, M. E., Montana a notes. Univ. Mont. Bull. no. 61 (Biol. Series no. iy pp. I-75. 19 9. Pounn, R., and CLEMENTS, Fr E., The phytogeography of Nebraska. 2d ed. Lincoln. pp. 442. 1900. 10. RAMALEY, F., Plant zones in the Rocky Mountains of Colorado. Science 26:642-643. 1907. , Woody plants of Boulder County. Univ. Colo. Studies 5:47-63- N w > = 1907. , Botany of northeastern Larimer County, Colorado. Univ. Colo. Studies §:119-131. 1908. , Climatology of the mesas near Boulder. Univ. Colo. Studies 13. 6:19-31. 1908. 14. , Forest formations and forest trees of Colorado. Univ. Colo. Studies 6:249-281. 1909 15. RAMALEY, F., and Rossins, W. W., Ecological notes from north-central Colorado. Univ. Colo. Studies §:111-117. 1908. 16. Rossins, W. W., Distribution of deciduous trees and shrubs on the mesas. Univ. Colo. Studies 6:36-49. 1908. , Climatology and vegetation in Colorado. Bor. Gaz. 49:256-280- IQIo. 18. Ropsins, W. W., and tea ns S., Distribution of conifers on the mesas. Univ. Colo. Studies 6:31- 19. RyDBERG, P. A., Flora of Cra Bull. 100, Exp. Sta. Colo. Agr. Coll. Fort Collins. pp. 448. 1 20. SCHNEIDER, E. C., The dictate of woody plants in the Pike’s Peak region. Colo. Co i. Publ., Science Series 12: no. 6; pp. 137-170. 1909- 21. ————,, The succession ot plant life on the gravel slides in the vicinity of ae $ Peak. Colo. Coll. Publ., Science Series 12: no. 8; pp. 289-311: 1917] VESTAL—FOOTHILLS VEGETATION 385 22. SHANTZ, H. L., A study of the vegetation of the mesa region east of Pike’s Peak: The Bouteloua formation. Bor. Gaz. 42:16-47, 179-207. 1906 23. TUCKERMAN, E., List of species of lichens collected by the Wheeler Survey. 24. Nv wu s) r U.S. Geog. Surv. 6:350, 351. VestTAaL, A. G., Prairie vegetation of a mountain-front area in Colorado. Bort. Gaz. 58:377—-400. 1914. . Watson, J. R., Plant geography of north-central New Mexico. Bor. Gaz. . WuitrorpD, H. N., The genetic development of the forests of northern Michigan. Bor. Gas. 31: 289-325. Igor. . Witttams, T. A., Lichens of pe ng Hills and their distribution. Bull. Torr. Bot. Club 20:349-355. Youne, R. T., The forest enone of Boulder County, Colorado. Bor. GAZ. 44:321-352. 1907. VEGETATION OF HAWAIIAN LAVA FLOWS VAUGHAN MAcCCAUGHEY (WITH TWENTY-TWO FIGURES) Introduction This paper is a survey of the more important types of vegetation which occur on the lava fields of the Hawaiian Archipelago and their ecological relations. It has particular reference to the sper- matophytes, as our taxonomic knowledge of the native land algae, lichens, bryophytes, and pteridophytes is still in a somewhat fragmentary and unsettled condition. The scope of the paper is further restricted by including only the arid or xerophytic dis- tricts where the lava flows are relatively barren. Under humid climate the flows rapidly disintegrate into rich volcanic soil and support a luxuriant rain forest. This paper is concerned with the ecology of the xerophytic regions, as these have largely been neglected in the literature of Hawaiian botany. There is a widespread association of ideas which couples tropical with humid conditions, due no doubt to the many semipopular accounts of the “tropical jungle” and to the types of vegetation usually exhibited in the northern conservatories. It requires a distinct readjustment of perspective to realize that many tropical regions possess large areas of extreme aridity. The Hawaiian Archipelago, situated just within the tropics in the center of the North Pacific Ocean, admirably illustrates this condition. Most of the popular and semitechnical accounts of the islands have emphasized the beautiful humid woodlands and have either ignored or given scant attention to the vast rocky waste lands of barren lava flow and cinder field. It has been the writer’s privilege, during a residence of 8 years in the islands, to have made many expeditions into these arid regions and to have ascended all of the high mountains of the group. This paper is an outgrowth of these trips, some of which have occupied many weeks. In order to make clear the ecological Botanical Gazette, vol. 64] [386 1917] MACCAUGHEY—HAWAIIAN FLORA 387 background of this lava flow vegetation, it is necessary to sketch briefly the salient features of the Hawaiian volcanic mountains. Detailed accounts may be found in such standard works as those of Hircucock, BricHam, DANA, and Dutton. It will be noted that the present paper deals largely with the ecological conditions under which the lava flow vegetation exists. A comprehensive annotated list of the lava flow plants is now appearing in the Journal of The Linnaean Society. Classification of islands From the standpoint of area occupied by lava flows, cinder fields, and other waste lands resultant from volcanic activity, the islands may be divided into two groups: (1) the lesser islands (Niihau, Kauai, Oahu, Molokai, Lanai, Kahoolawe); and (2) the greater islands (Maui and Hawaii, see figs. 1, 2). The lesser islands are, as a whole, of much greater antiquity than Maui and Hawaii. The erosive agencies have been at work for a much longer time, hence the lava flows have been almost wholly turned into soil. There are some traceable flows still existent on some of the lesser islands, Kauai, Oahu (figs. 3, 4, 5), Molokai, and Lanai, for example, but these are relatively non-consequential as compared with the great stretches of lava covered country on Hawaii and Maui. The lava waste lands, above the timber line, on Mauna Loa alone, for example, occupy a greater area than the entire island of Oahu, Kauai, or Molokai. Thus a discussion of the vegetation of the Hawaiian lava flows is naturally restricted chiefly to a consideration of the islands of Maui and Hawaii, the largest and youngest end of the long archipelago. No account is given in this paper of the tiny islands which are strewn over a long axis for 1800 miles to the westward of the larger, inhabited islands. Some of these are volcanic rocks, but the majority are tiny reefs and shoals.t Their total area is only 6 sq. miles. All are highly xerophytic. IsLAND OF HAwat.—Hawaii, the largest island of the archi- pelago (4015 sq. miles), is about the size of the state of Connecticut, with a maximum diameter of 93 miles (fig. 2). Its area is greater * MacCaucuey, V., The little end of Hawaii. Jour. Geography 15:23-26. 1916. 388 BOTANICAL GAZETTE [NOVEMBER than that of all the other islands combined. volcanic masses. It is composed of 5 The northernmost, the Kohala Mountains, is of extreme antiquity, deeply eroded, and probably as old as Kauai. € | 5 \ \ “ yy; ing ij WS \ : Ny ’ " | Ws 7 infZ Wags Mp = ne 7 g \\ si 7% y) 4” i ot = F. ee HE : er: aS ice: > == — =— _— —— ae Soe cee itt \ Gf \\ Ny | g Z > W Ze} Zl flows. Fic. 1.—Island of Hawaii, showing high mountains and principal recent lava Mauna Kea and Hualalai, next toward the south, have become “extinct” within comparatively recent times; a lava flow issued from Hualalai in 1801. Mauna Kea has given no manifestations of activity within historic times. It is the highest point within the North Pacific Ocean. 1917] MAcCAUGHEY—HAWAIIAN FLORA 389 The two southern mountains, Mauna Loa (figs. 6, 7) and Kilauea, are active volcanoes. Their summit craters have exhibited spectacular activity at intermittent periods throughout historic time, and vast lava flows have emanated from their flanks. A large flow issued from the southern slopes of Mauna Loa in May 1916. Loa dominates the island of Hawaii and is the greatest volcanic mountain in the world. The elevations of 5 volcanic A ry wi ‘iy “re Fic. 2.—Island of pep Mount Haleakala comprises entire eastern lobe of island; lava flow country at summit, in caldera, and on southeastern slopes of moun- tain; regions are largely shionbe de, with exposed lava fields, fields of cinder and ash, cinder cones, and pit craters. masses of Hawaii are as follows: Kohala Mountains, 5489 ft.; Mauna Kea, 13,825 ft.; Hualalai, 8269 ft.; Mauna Loa, 13,675 ft.; Kilauea, 4000 ft. HALEAKALA ON Maut.—Haleakala (fig. 8) is the great mountain that forms the entire eastern portion of the island of Maui. The summit is 10,032 ft. above sea level. It contains a great volcanic caldera, one of the largest in the world, 7.5 miles long by 2.5 miles wide and over 2000 ft. deep. This mountain, often called East Maui, is very much younger than the deeply eroded western mass. 390 BOTANICAL GAZETTE [NOVEMBER Fic. 3.—Tufa cones and xerophytic lava fields, Oahu; open crater to right, Koko Crater; hill beyond to left, Koko Head. Fic. 4.—Arid headland, Maka-pu’u, Oahu, illustrating ancient lava sheets exposed by extensive erosion; note stratification of lava flows and erosion of flows at sea level. 1917] MACCAUGHEY—HAWAIIAN FLORA 391 Maui is a volcanic doublet made up of two masses of widely different ages. Haleakala probably ceased activity at about the same time as Mauna Kea. The windward, northern face of Haleakala, like that of all the Hawaiian mountains, receives torrential rainfall (400 inches per annum) and is densely covered with jungle forest. The leeward, southeastern slopes are conspicu- ously arid and barren. In its geological and botanical aspects Haleakala is much more closely related to Kea and Loa on Hawaii Pe Fic. 5.—Manana or Rabbit Island, deeply eroded tufa cone, isolated as small barren islet off windward coast of Oahu, near Maka-pu’u Point; about 2200 ft. long and 400 ft. high, separated from main island by channel of 1 7 vegetation sparse and stunted, no arborescent vegetation. than to its associate West Maui. It is separated from Hawaii by a relatively narrow channel, 26 miles wide and 1032 fathoms deep. From the standpoint of this paper it will be considered as one of the Kea, Loa, Hualalai family. THE FOUR GREAT MOUNTAIN MASSES.—These four great volcanic mountains, Haleakala, Kea, Loa, and Hualalai, closely resemble each other in a number of important ecological particulars: (1) their summits rise 8000-14,000 ft. above sea level and are frequently covered with snow; (2) there is a large treeless zone on the summit of each; this is most extensive on Loa, Kea stands next, then 392 BOTANICAL GAZETTE [NOVEMBER Fic. 6.—Summit and upper slopes of Mauna Loa as seen from summit of Mauna Kea; note very gentle slopes of Loa, and two cinder cones (explosive vents) in fore- d f Hualalai; clouds lying at elevation of n foreground, Fic. 7.—View of Loa from summit c 7000-8000 ft.; note xerophytic vegetation 1917] MACCAUGHEY—HAWAIIAN FLORA 393 Haleakala, and lastly Hualalai, the smallest of the four mountains; (3) the summits are marked by volcanic vents; either an active crater (Loa); or an extinct caldera (Haleakala); or great numbers of cinder cones (Kea); or by innumerable pit craters and cinder cones (Hualalai); all of these are large and tangible evidences of the earth forces by means of which the mountains were built up to their present height; (4) the mountains rise directly and gradu- ally from the sea, without intervening lowlands or plateaus; (5) the —Cinder cones on floor of Haleakala caldera; at extreme upper left are some eae sword plants (Argyroxiphium sandwicensis var. macrocephalum). slopes and flanks of each mountain are covered by thick blankets of lava, cinders, and ash, which in the arid summit and leeward regions have undergone little or no erosion; (6) each mountain has a lower windward region which receives heavy precipitation; this rain, amounting to several hundred inches per annum in many localities, has caused the rapid decay of the lava flows in these zones and has covered the flows with luxuriant rain forest; the original flow structure is obliterated beneath heavy beds of soil and vegetation. This paper does not include the humid areas, 394 BOTANICAL GAZETTE [NOVEMBER Cinder cones The slopes and summits of all four of the great mountains are thickly sprinkled with cinder cones (fig. 9). These vary in height from 200 to 1000 ft., with very steep slopes of 30-40°. They are composed of volcanic ash, cinders, scoria, and other ejecta, and are frequently strewn with volcanic bombs and other lava blocks. These cones are most numerous on Kea and Hualalai; they are plentiful in the caldera of Haleakala and on the leeward slopes, and are by no means infrequent on the broad flanks of Loa. Many of these cones are more or less completely covered with vegetation and are conspicuous from a dis- a tance, serving as landmarks. ‘ PIT CRATERS.—A second Bat 2 type of volcanic vent of distinct ¥ ecological interest is the pit : crater (figs. 10, 11). This is f typically a circular pit, its ey mouth flush with the surround- ing country, its walls vertical or eee ty funnel-shaped, and its floor Fic. 9.—Summit plateau of Mauna littered with volcanic débris. Kea, showing numerous cinder cones; In diameter these pits vary from all high mountains of Hawaii, from sea Oe Peek COs Ye a level to summit tegions. case of the smaller ones) to several miles in the case of the gigantic pits of Kilauea and Loa. The pits of greatest botanical interest are those of intermediate size, namely, 100-300 yards in diameter and of similar depths. There are many pits so deep and narrow that no floor is visible from the rim. The pit craters occur indiscriminately in the rainy forest zones and on the barren slopes and summits. In the former case they are densely filled with trees and jungle litter; their mouths are often hidden by vines and other vegetation, and they constitute a serious menace to the traveler and to livestock. Those that occur in the arid sections are of particular botanical significance, as their steep walls prohibit invasion by cattle and goats, and the vegeta- tion within them is unmolested. Thus they constitute botanical MACCAUGHEY—HAWAIIAN FLORA Fic. 10.—Floor of pit crater, close to Kilauea, fissured in mosaic manner with remarkable eee, although nearly 40 years have passed since last eruption, there has been practically no plant invasion in this crater, due to its unfavorable situation. Fic. 11.—Floor and wall of pit crater close to Kilauea, largely covered with pa-hoe- le walls covered with Metrosideros polymorpha, 10-20 ft. high 396 BOTANICAL GAZETTE [NOVEMBER oases in otherwise barren country and may be compared with the kipukas in the a-a flows. Many remnants of the primitive flora are today making their ‘‘last stand” in these tiny areas where they are protected from wild livestock, the greatest enemy of the in- digenous vegetation. Finally, the conditions of shade and moisture Fic. 12.—Diagram illustrating formation of kipuka in midst of lava fields. are more likely to be favorable in the pits than on the exposed open lava flows, and the plants in the pits exhibit more normal growth forms than those in the open. Kipukas.—This Hawaiian word, meaning an oval hole or depression, is a convenient desiniating for small areas that, owing to minor topographical irregularities, have escaped being covered by the lava flows which surround them (fig. 12). The flow may be 1917] MacCAUGHEY—HAWAIIAN FLORA 397 split or deflected so that these small patches of forest remain unscathed. Like the pit crater, the kipuka is often a botanical garden in the midst of an arid waste land. The lava which surrounds the kipuka, and which may be 15- 30 ft. higher than the floor of the latter, serves as a protection from wild cattle and goats. The kipukas frequently contain a very rich flora, a remnant of the original forest cover. These patches are usually of very limited area, not more than 2 or 3 acres, and are sharply limited by the impinging lava beds. The soil within the area is usually deep, black, and rich, and of great antiquity. There are hundreds of these kipukas on the lower slopes of the great Hawaiian volcanoes, but only those in the arid regions retain their individuality. Those in the humid regions are hidden under the rain forest. Puu Waa-waa.—An ancient cone of minor topographical importance, but of extreme interest from the standpoint of the geological and botanical history of the archipelago, is Puu Waa- waa, in North Kona, Hawaii. This cone is about 6 miles north of the summit of Hualalai, near the Loa flow of 1859. Its elevation is about 3300 ft..above sea level. It is 500 ft. high, with steep, deeply fluted sides. The numerous erosion ravines which radiate from the summit and produce this corrugated appearance (the native name means “fluted hill’) are 50-75 ft. deep. The cone. is composed of volcanic ash and cinders, and exhibits the quaqua- versal structure of the typical explosive cone. It has been deeply encircled by lava streams from Hualalai and Loa. Studies by Cross? of the lavas which underlie Puu Waa-waa have demonstrated that these lavas are trachytic, and vastly older than the basaltic lavas which now largely cover them. is hill is undoubtedly a vestige of an ancient island mass now sub- merged beneath newer lava. Botanical explorations by Rock have strikingly confirmed the antiquity of the Puu Waa-waa region as contrasted with the much younger regions which sur- round it. Many evidences of a primitive flora have been found, a flora that has largely disappeared from other portions of this ? Cross, Wartman, An occurrence of trachyte on the island of Hawaii. Jour. Geol. 12:510-523. 1904. : 398 BOTANICAL GAZETTE [NOVEMBER island. The Puu Waa-waa region, like some of the pit craters and kipukas, is a botanical oasis in the midst of a desert and harbors much material of unquestionable antiquity. VOLCANIC DusT.—In order to treat comprehensively the ecologi- cal aspects of the lava regions, it is necessary to include a statement concerning volcanic dust (fig. 13). The Hawaiian volcanoes have Fic. 13.—Pumice fields, Kilauea volcano; chief plants, Metrosideros polymorpha and various xerophytic species; white patches in foreground, lichens; in distance, to right, is ohia forest, Metrosideros polymorpha. been conspicuously quiescent in their activities during historic times; the outpourings of lava have been relatively gentle and non-explosive. There is much evidence, however, which indicates tremendous explosive eruptions at various periods in the history of the volcanoes, and at least one of these (Kilauea, 1790) has fallen within historic times. Among the most abundant of the varied products of these explosive eruptions, in the Hawaiian Islands as in the case of vol- canoes generally, is volcanic dust. Extensive deposits of dust 1917] MACCAUGHEY—HAWAIIAN FLORA 399 occur on the leeward slopes of Haleakala and in the caldera itself; on the leeward slopes of Kea and Loa; and great beds to the leeward of Kilauea. Perhaps the largest area is in the Ka-u district, where, according to Hircucock,’ it covers “an area of 300 sq. mi.”’ It is not within the province of this paper to enter into any detailed account of these dust deposits, but two important floristic relations may be enumerated: (1) the obliteration of any vegetation that may have occupied the region previous to the deposit; (2) the thick layer of ashes, if rainfall or irrigation be sufficient, forms a rich and mellow soil and transforms what would otherwise have been lava waste land into productive country. The plantations and ranch lands of Ka-u owe their origin to this. It may be pointed out, in conclusion, that similar deposits of volcanic ash, of great area and thickness, occur in Central America, Mexico, the Sierra Nevadas, the Great Basin, Utah, Montana, South Dakota, Nebraska, Kansas, Washington, Oregon, Alaska, Canada, and many other places. Ecological factors SLoPpE.—There is considerable variation in the gradient of the various high mountains, but on the whole it is remarkably gentle. Loa has a deceptively gentle slope, averaging 4-6° and not over 8° at the steeper places. Its outline against the sky is that of a very much flattened dome, or “whaleback.”’ The slopes of Kea and Haleakala are more abrupt, usually about 12°, but sometimes as high as 15°. Hualalai is the steepest of the 4 mountains, par- ticularly near its summit, with an average slope of 14-18°. The cinder and ash cones have slopes which lie at the critical angle for material of this character, namely, 30 or 40°. The mountains are all relatively young and have not been carved by deep, pre- cipitous-walled amphitheaters of erosion, as have the mountains of Kauai, Oahu, eastern Molokai, and West Maui. PRECIPITATION.—The only comprehensive records of rainfall in the Hawaiian Islands are those made by the United States Weather Bureau and the United States Hydrographic Survey. The records of the former are collaborated from the reports of 3 Hircucock, C. H., Volcanoes of the Hawaiian Islands, p. 153- 400 BOTANICAL GAZETTE [NOVEMBER about 50 observers, scattered at various points on the islands. As these observers are stationed in or near human settlements, and as these settlements are situated in regions of at least moderate rainfall, it happens that there are no records covering the areas which form the central theme of this paper. The great upper slopes of Loa, Kea, Hualalai, and Haleakala, having a total area much greater than that of the peripheral lowlands, are uninhabited waste lands and without meteorological data comparable to that of the agricultural. lowlands. The Hydrographic Survey, interested primarily in the rain sections and the streams, has naturally avoided the great arid and streamless areas which are considered in this paper. Hence it is not possible to present extensive tables showing accurately the precipitations on these arid districts. It is necessary to emphasize the importance of the trade winds as the rain-bearing winds of the islands. These winds blow from the northeast almost continuously through a large portion of the year. The main axis of the archipelago lies from northwest to southeast, so that the islands lie across the path of the trades, and hence develop strongly differentiated windward and leeward climates. The warm trades sweep across vast stretches of ocean before reaching the islands, and are consequently saturated with moisture. Upon striking the cool mountain slopes very heavy precipitation ensues, often totaling several hundred inches.* In this zone the luxuriant rain forest reaches its finest development. The leeward slopes, however, are robbed of this torrential rain; the winds that reach them are usually dry and parched, and the climate is arid or semiarid. SNoW AND IcE.—The high mountains of Maui and Hawaii are often snow-capped. This is particularly true of Kea, literally the “white mountain,” which is prevailingly snow-crowned from November to March and intermittently at other seasons. At the season of greatest snowfall the snow line often reaches down as low as gooo ft.; at other seasons there are frequently extensive patches of snow at the higher levels. Near the extreme summit +The greatest annual precipitation officially recorded in the Hawaiian Islands is 561 inches, in 1916, on Waialeale, Kauai, by the Hydrographic Survey. 1917] MACCAUGHEY—HAWAIIAN FLORA 401 of Kea, at an elevation of 14,000 ft., is a small perennial pond, Wai-a’u, about 125 ft. in diameter. This pond is situated in an ancient crater basin and is fed by the melting snow. It is frozen during a major part of the year, even in midsummer. Ice occurs in the deep fissures and caverns in the neighborhood of the sum- mits of Kea and Loa throughout the entire year, and during late winter it is relatively abundant. SUMMIT REGIONS.—The treeless character of the summits has already been mentioned. The timber line is very low, indeed , unusually low as compared with that of mountains in other parts of the world. Hatt’s’ explanation so accurately summarizes the local conditions that it is reproduced herewith: Elevation has put a sharp limit to the forests on the islands of Hawaii and Maui at from 6000 to 8000 ft. This leaves very large areas of Mauna Loa, Mauna Kea, Hualalai, and Haleakala devoid of forest, and they have always been so. The mountains of the other islands, being under 6000 ft., are forested to their summits. Six to 8000 ft. is a surprisingly low timber line, considering the favorable conditions of soil, moisture, and temperature which prevail at that altitude in Hawaii. The sufficient reason seems to be that the species composing the native forests are all representatives of the torrid zone, and in these islands, which lie right at the edge of the Tropics, find their limit at the low altitude named. SEEPAGE.—The physical structure of the lava flow is such that Seepage takes place with extreme rapidity, and in the typical flow country there is absolutely no surface water. This abnormally high percolation greatly heightens the physiological aridity of the lava as a substratum for plant life. Both the a-a and the pa-hoe-hoe types of lava are highly ramified with crevices, caverns of all sizes, and long tunnels or lava “‘tubes.’’ Thus a vertical section of the mountain would reveal a copiously spongy texture, with large caverns sloping toward the sea. Dawna’s® account may be appro- priately quoted in this connection: Over the leeward sides . . . . where rains are infrequent, a black desert everywhere prevails, and there is, with rare exceptions, only an alternation between the smoother fields of cooled lava and the rougher districts of scoria. Yet over the barest fields there is always a sprinkling of verdure, growing 5 Hatt, W- L., Forests of the Hawaiian Islands. 1904 (p. 16). 6 Dana, J. D., Geol. U.S. Explor. Exped. 10:1849 (pp. 159-160). 402 BOTANICAL GAZETTE [NOVEMBER from the many crevices or cavities. Whatever showers fall on this portion of Hawaii are at once absorbed by the cavernous rocks; and consequently through its whole extent, south and east, there are not two permanent streamlets. Water is to be found only in caverns; and often a journey of some miles must be taken by the villager to supply himself for his daily consumption. All the caverns about the lower parts of the mountains have been well explored for this necessary of life. There is probably no other region in the world where rainwater disappears with greater rapidity than on the leeward slopes of the Hawaiian Mountains. The honeycombed lava flows swallow it up, and convey it to the sea through deep subterranean channels. Thus the aridity of the lava country is compounded by 3 factors: low precipitation, high evaporation, rapid percolation. EvAPORATION.—An_ ecological factor of probably greater importance than either precipitation or percolation is that of high evaporation, which characterizes the Hawaiian flows, as it does all arid regions. This very high evaporation is strongly productive of xerophilous structures and is probably more potent than any other single factor. The lava flow In order to elucidate the structural peculiarities of the lava country as related to plant life, a brief synopsis of the formation of a typical flow may be presented. This is adapted from Hosss’s’ account. j The lava either quietly melts its way to the surface at the time of outflow, or else produces one or more fissures for its egress to the accompaniment of vigorous local earthquakes. In either case, if the lava issues at a point far below the crater, the hydro- static pressure causes gigantic lava fountains to arise at the point of outflow. The fluid, incandescent rock shoots up to heights which range from 200 to 700 ft: or more above the surface. In the 1852 eruption of Loa a fountain of lava 1000 ft. broad rose to a height of 700 ft. Be ENT ol ee es BOGE. ee oe ti Fe ees 0.20 ei id Se Oe Os has ala as 0.02 TS 8 gle Meade Soap naire ae Ca ged &: 8 DORE Re ares aetciameneres Ort 0.10 soils derived from the weathering of these basaltic lavas are very different from those common on the mainland of the United States. Burgess? states as follows: They are primarily basic in composition, whereas those of North America, for example, are ac cidic.. ..The bases or framework of Hawaiian soils are the oxides of iron and aluminum, whereas the basis of mainland soils is silica. A glance at the following table will show these great differences better than words can express them. These figures represent averages of large numbers of soil analyses made by the “‘absolute” or “fusion”? method. The column marked “Mainland soils” represents averages of soil analyses from almost every state in the Union and from provinces in Canada. The column labelled “Hawaiian soils” gives average figures for over 300 composite samples of soil from the leading types on all of these islands. All of these analyses were made here and under similar conditions. Hawaiian soils | Mainland soils Per cent Per cent Basic constituents.......... 63.717 18.9 Acidic constituents......... 36.458 81.014 RG PAL. 6.55 355 anes 59.240 13.250 CAD ic Rick eee ce oe 0.698 0.830 TD sien oe ate ie a Sa weer e oO. 77% Be eee 0.737 1.622 INA AS es Beer 1.420 2.229 The prevailing low summit temperatures have already been noted. The annual mean temperature of Mauna Loa at the timber line is estimated by the United States Weather Bureau as sa F, and the summit temperature as 35°. The Bureau states “‘in the ® Rept. Haw. Sugar Planters’ Expt. Station, Honolulu. rors (p. 62). 1917] MACCAUGHEY—HAWAIIAN FLORA 409 absence of actual observations in the higher levels, a temperature decrease of 1° F. is assumed in each 320 ft. of ascent.” The annual mean summit temperature of Kea is given as below 30°. It should be emphasized that very much lower temperatures than these prevail during a considerable portion of the year, especially at night, and are accentuated by the high winds. During the brilliant cloudless day the black lava sheets absorb great quantities of heat, and the aerial temperatures near the ground become very high. At nightfall, however, a very rapid chilling of the air ensues, and the thermometer drops in a few hours to the neigh- borhood of freezing point. This sudden drop is familiar to all who have ascended the high peaks. This wide diurnal range of aerial summit temperatures is in striking contrast to the equable and monotonously invariable temperatures of the littoral regions. TEMPERATURES OF LAVA AND CINDER FIELDS.—Reference has already been made to the low temperatures which prevail at the summit regions. Another phase of this extremely interesting ecological factor remains to be considered, namely, the compara- tively high temperatures which characterize the lava and cinder fields themselves during the daytime. All of these volcanic deposits are black or very dark in color. They absorb vast quantities of heat during the uninterrupted diurnal period of insolation. Those who have traveled across the lava waste lands well know that by the middle of the afternoon the surface of the rock is distressingly hot. The surface, the rock layer immediately below it, and the aerial layer immediately above it have temperatures much higher than the prevailing aerial temperatures. This condition is similar to that reported by investigators of other desert regions. Mac- Dovucat™ notes that ‘the sandy soil around the roots of small herbaceous plants in the Grand Canyon, Arizona, . . . . exhibited temperatures as high as 148° F.” It is to be further noted, as MacDoveat states (loc. cit., p. 77), that ‘‘these extreme tempera- tures are met only by the roots of species spreading in the surface layers of the soil.” Deep-rooted species are not so likely to be affected. % U.S. Weather Bureau, Hawaii Station, Ann. Rept. 1915 (p- 2). MacDoveat, D. T., Botanical features of American deserts, p. 82. 410 BOTANICAL GAZETTE [NOVEMBER No thermograph records are available for subterranean tempera- tures in the Hawaiian lava flows, but such will very likely correspond closely with the results obtained by Cannon.” In his study of the root relations of desert plants at Tucson, an almost continuous record was made of the soil temperatures at a depth of 15 cm. for the 5 years 1905-1909. CANNON states: The record shows an undulating record of which the curve crests cor- respond to the warmest for each day, and the depressions the coldest. The crests . . . . are remarkably uniform in height, as also the depressions are uniform in depth. The difference between the crests and the depressions is about 8° F., with 12° as the greatest variation. .... Owing to the lagging of the soil temperatures, as compared with those of the air, the maximum is not attained until about 6 P.M., and the minimum about midnight. A careful quantitative and qualitative investigation of the root relations of the lava inhabiting species is yet to be made, but it _ already gives promise of yielding some valuable contributions to our knowledge of plant ecology. To quote again from MaAc- Doveat (loc. cit., p. 82): It may be said, in conclusion, that the facts disclosed as to the actual temperatures in the soil, the diurnal and seasonal change therein, lead to the belief that the differences in temperature of the aerial and underground portions of plants cannot fail to be of very great importance in the physical and chemical processes upon which growth, cell-division, nutrition, and propagation depend. The determination of the effect of differences in temperature between the roots and aerial shoots has received but little consideration from the physiologist and the geographer. Plant invasion on lava flows The rate and amount of invasion is chiefly dependent upon two factors: (1) proximity of adjacent vegetated regions from which invasion may take place; (2) amount of precipitation, determining the character and abundance of invading forms. A lava flow which cuts a path through the humid jungle forest is soon (30-50 years) disintegrated and overgrown. A lava flow on an arid summit slope (8000-10,000 ft.) will remain practically naked for centuries. Between these two extreme types every intermediate stage can be found (figs. 11, 19, 20). 2 Cannon, W. A., Root habits of desert plants, p. 20. MACCAUGHEY—HAWAIIAN FLORA nd G. 19.—Floor of Kilauea, composed of black, lobular, hummocky pa-hoe-hoe; in foreground are Metrosideros polymorpha, Vaccinium reticulatum, Sadleria lan Sathdeliee: etc. ny Fic Ping poi on floor of Kilauea crater; near foot of wall; note that floor is aihentl Bases are Sadleria cyatheoides; scrubby trees near top of slope are M7 eee ae 412 BOTANICAL GAZETTE [NOVEMBER In 1912 ForsBeEs™ published some preliminary observations of plant invasion on lava flows. His principal findings, which coincide - with the observations of the writer, may be summarized as follows: 1. Lichen flora is much more abundant on the a-a than on the pa-hoe-hoe and develops on the former at a much earlier date than the latter, other conditions being the same. 2. Ferns (such as Polypodium and Sadleria) and phanerogams (such as Metrosideros and Sophora) do not establish themselves upon the a-a until long after they have established themselves upon the pa-hoe-hoe, other conditions being the same. 3. The species occupying a recent flow are the same as those occupying older flows in the immediate vicinity. 4. Soil is formed on the pa-hoe-hoe at a much earlier date than on the a-a. 5. Acacia koa, a phyllodious species adapted to semi-xerophytic conditions, is the prevailing tree in the leeward upper forests of the middle zone, finally establishing itself upon the ancient flows as the dominant and final type. Altitudinal ranges of lava flow species Horizontal zonation with reference to altitude is strongly developed on the slopes of the Hawaiian mountains. As one ascends a great volcano like Loa or Kea, one finds pronounced changes in the vegetation with every thousand feet increase in elevation. From the standpoint of this paper the following large zones or belts may be recognized: lowland (littoral to 1500 ft.), lower forest (1000-2000 ft.), middle forest (1800-6000 ft.), upper forest (6000-g000 ft.), summit (gooo-nearly 14,000 ft.). The summits of Kauai, Oahu, Molokai, West Maui, and Kohala rise to 4000-6000 ft. only and are very boggy. They are considered in another paper.“ The point must be emphasized that there is a very considerable variation in the altitudinal limitations of these zones on the mountains of the different islands and on different slopes of the same mountain. In some regions the upper forest 3 ForBEs, C. N., Plant invasion on lava flows. Occ. Pap. Bishop Mus. 19f2.- ™ MacCavuGHey, VAUGHAN, Vegetation of the Hawaiian summit bogs. Amer. Bot. 22: 45-52. 1916. 1917] MACCAUGHEY—HAWAIIAN FLORA 413 may cease at 6500 it., in others the lower forest may extend almost to sea level; the figures must all be interpreted with considerable latitude for local deviation. - ie 2S E a > $ Pies | ee ¢ 2) ae % Ba2 [ r- & cs a oe oa ie ewes pe. ap ee ee IVE 23s | — Re SSeeea ss | : = ti 7 Bagi > es — ; < ip a 7000 | 3 ¢ ) 283 aS 2 5 2 3 j a 3 BSSGCR Set 32% OO BAe ee ee ee P eee s3— 333 mn 2 223 AEs 5sh + Ss = eS 3s & ur S cee See 383 +. g 2 ase een ee fee TF nee @ TEE ER x 3 aa oe So ee ee es sas & ga | ee a eee 3000 aa oe Lt 3 s a 2 2 3 7 2 | = = E > £ = eau Be ea *; i; Ee sa on §¥—4—— ae ae 3 BERR SG - I~ i > am i000 fee 3 og BE Q a § ips 2 4 Fic. 21.—Diagram showing altitudinal ranges of some representative plants of lava flow country; figures indicate feet above sea level. Upon classifying the lava flow species with reference to their altitudinal ranges (fig. 21), it is significant to note the great number of ranges and the fairly close adherence of each species to its range. Three general types of range may be cited: (1) wide-ranging species (Metrosideros polymorpha, Sophora chrysophylla, Myoporum 414 BOTANICAL GAZETTE [NOVEMBER sandwicensis); (2) species with moderate range (Charpentiera obovata, Daucus pusillus, Gossypium tomentosum); and (3) species with a very narrow range (Argyroxiphium virescens., Geranium spp., Straussia spp.). Xerophytic characters of lava flow plants PuBESCENCE.—Of the 182 species listed as occurring on the lava flows, 62, or 33 per cent, are characterized by coatings of hairy or woolly tomentum. The pubescence may cover the under surfaces of the leaves, the entire leaves, the young shoots, the inflorescences, or all aerial parts of the plant. The most pro- nounced examples of tomentose envelopment occur in the follow- ing genera: Argyroxiphium, Gnaphalium, Chenopodium, Sida, Gossypium, Nototrichium, Waltheria, Abutilon, Geranium, Lobelia, and Plantago. The point must be emphasized that with many indigenous Hawaiian plants there is exceeding variability as to pubescence; plants of the same species from various localities will show every gradation from perfectly glabrous to very hairy. This variation does not give evidence of intimate association with ecological habitat, although in a general way the glabrous forms characterize the rain forest and the pubescent forms the more arid situations. There are many exceptions to this rule, however, and a very considerable proportion of the pubescence seems to be without obvious ecological significance. WAXY OR VISCID EXCRETIONS.—These are much less prevalent than the pubescent or coriaceous protections. Typical instances are Argemone mexicana, Dodonea eriocarpa, Gardenia Brighamt, Pisonia sandwicensis, P. inermis, Plumbago zeylanica, Raillardia spp., Sphacele hastata, Styphelia spp., Tetramolopium spp., Vac- cinium spp., Myoporum sp. THORNS AND PRICKLES.—A small number of the lava flow plants are thorny or prickly; the condition characterizes intro- duced weeds rather than the indigenous vegetation, as shown by the following: Prickly Thorny Total 4 I 5 iitremte so 4 5 9 ¢ 1917] MacCAUGHEY—HAWAIIAN FLORA 415 Acacia Farnensiana, Amaranthus spinosus, Argemone mexicana, Caesalpinia Bonducella, Cyanea solanacea var. quercifolia, Rubus hawatiensis, Sida spinosa, Solanum incompletum, Opuntia tuna, Lantana camara, and Prosopis juliflora are representative plants of this class (fig. 22). FOLIAGE MINUTE OR SCALELIKE, or showing strong xerophilous modification.—Acacia koa and A. koaia (phyllodia), Exocarpus Gaudichaudii, Portulaca sclerocarpa, Silene struthioloides, and Sityphelia spp. are examples of very small foliage. Cassytha- jiliformis and Viscum articulatum, two parasitic plants, have minute or vestigial leaves. Drcimpuous HABIT.—The deciduous habit is quite rare among Hawaiian plants, either in the rain forest or on the lava fields. Only 3 deciduous species occur on the lava flows, namely, Erythrina monosperma, Sapindus saponaria, and Reynoldsia sandwicensis. DECUMBENT, STRAGGLING, OR VINELIKE HABIT.—A very large number, nearly 60 in all, or 33 per cent, of the lava flow plants are either habitually prostrate or decumbent, or assume these growth- forms on the lava. Genera containing representative species of these habits are Abutilon, Argyreia, Boerhaavia, Caesalpina, Cap- paris, Cassia, Chenopodium, Cocculus, Embélia, Euphorbia, Fragaria, Gossypium, Ipomoea, Lepidium, Lipochaeta, Meibomia, Mucuna, Osteomeles, Plumbago, Portulaca, Raillardia, Ranunculus, Rubus, Rumex, Scaevola, Sicyos, Sida, Solanum, Stenogyne, Styphelia, Tetramolopium, Vicia, Vigna, and Wikstroemia. Compact basal heads or rosettes are formed by such plants as Argyroxiphium spp., Gnaphalium spp., Plantago pachyphylla, Sisyrinchiwm acre, Sonchus, etc. SuccULENCE.—This typical xerophytic character is relatively uncommon in the lava flow flora. The few examples are mostly introduced weeds, as Portulaca,Opuntia, Bryophyllum, C heno podium, Sonchus. Lignescence, representing the other extreme of struc- tural adaptation to aridity, is the dominant condition. - HiGH PERCENTAGE OF LIGNEOUS FoRMS.—Upon examining a tabular statement of the habital characters of the lava flow flora, one is immediately impressed by the high proportion of ligneous and semi-ligneous forms. Over 70 per cent are woody, and this 416 BOTANICAL GAZETTE [NOVEMBER proportion would be heightened if a number of herbaceous peren- nials with woody bases or stocks were included. This ligneous character is not confined to the lava flow plants, however, nor is Fic. 22.—Typical ligneous thorny species dominant in xerophytic habitats, on lava flows and coastal plains, Acacia Farnensiana; man is standing on explosively produced tufa strata. 1917] MAcCAUGHEY—HAWAIIAN FLORA 417 it especially typical of them. A very large proportion of the indi- genous vegetation in the humid forests is shrubby or arborescent. In the Hawaiian Islands woodiness is to be interpreted, not as a xerophytic feature, but rather as a result of long continued plant growth (in terms of the individual plant) under unfavorable conditions. The low temperatures and excessive humidity of the rain forest belt are probably just as unfavorable for optimum plant growth as are the high temperatures and excessive aridity of the lava fields. Both habitats result in the production or modification of a large number of very lignescent, suffruticose, dwarfed, slow growing species (tables I and II). TABLE I HABITAL ANALYSIS OF THE LAVA FLOW FLORA Class | Frequent | Rare | Total EPOCH Nace ees 48 Io 58 eS Gg oni ele 65 2 67 Herbaceous perennials 29 4 33 ANDURIE G3 25a 3 24 2 26 TABLE II ENDEMICITY AND LIGNESCENCE OF LAVA FLOW PLANTS* Not endemic | Total Class Endemic Woody throughout. . go 108 Partly woody.....-.. 28 10 38 Herbaceous......... 12 24 36 ROME ccieerveswes | 130 §2 | 182 pes. 5 bo ber vg io" oe che total lave ow Hora is tomposed of woody and partly Lal age we Roor sysTEMS OF LAVA FLOW PLANTS.—No comprehensive data are available on this interesting subject. The observations of the writer would tend to point to the comparatively deep rooted- ness of the woody species. The aridity of the flows has already been described. Deeply penetrating roots may be considered as absolutely essential for the existence of perennial plants on a rocky stratum as dry as the typical lava flow. The roots of such species 418 BOTANICAL GAZETTE [NOVEMBER as the writer has had occasion to examine have in every case proved to be exceptionally long as compared with the proportions of the aerial parts. The roots run down for long distances into the fis- sures in the flows, and often pursue the most devious courses. The following plants exhibit this condition: Acacia koa, A. Far- nensiana, Alphitonia excelsa, Artemisia australis, Cassia Gaudi- chaudii, Cheirodendron Gaudichaudii, Coprosma montana, Dodonaea eriocarpa, Erythrina monosperma, Geranium cuneatum, Gossypium — tomentosum, Lipochaeta subcordata, Metrosideros polymorpha, Myoporum sandwicensis, Osteomeles anthyllidifolia, Perrottetia sand- wicensis, Psidium guayava, Reynoldsia sandwicensis, Rumex gigan- teus, Senecio vulgaris, Sida fallax, Sophora chrysophylla, Styphelia tametameiae, Waltheria americana, Wikstroemia spp., Xylosma Hillebrandia. Sclerophyllous formations A considerable proportion of the lava vegetation may be classified as sclerophyllous. The leaves of these species are thick coriaceous, usually with glistening, highly reflective upper surfaces. Antidesma, Chrysophyllum, Coprosma, Maba, Metrosdieros, Notho- cestrum, Osmanthus, Pelea, Pisonia, Pittosporum, Pterotropia, Sideroxylon, Styphelia, Wikstroemia, and Xylosma are genera con- taining typical coriaceous-leaved species. It should be noted that Hawaii does nt exhibit the extreme sclerophyllous condition, but rather a semi-sclerophylly. For example, many species with sclerophyllous foliage do not show noticeable dwarfing; indeed, they may be trees of considerable stature. In the Hawaiian Islands the sclerophyllous formations occur at the higher levels (5000-9000 ft.), and altitude seems to be a dominant factor in their origin and zonation. AGE OF LAVA FLOW VEGETATION.—The vegetation of the lava flows is largely comprised of woody, long lived species. These acquire the aspect and habit of senility at a relatively early stage in their life cycles. The unfavorable conditions of the environ- ‘ment stamp themselves upon the physiognomy of the individual ‘plants and of the formations as a whole. The woody species give every evidence of great age and slow growth. Shrubs 4-6 ft. 1917] MACCAUGHEY—HAWAIIAN FLORA 419 high show ages of 30 to 4o years; trees 15-20 ft. high, ages of 50 to 7° years; and trees of 40-60 ft. high, ages of 100 to 200 years or older. It may be stated as a general conclusion that the ligneous plants of the lava flows, like those of other deserts, attain great age and assume the aspect of senility at an early period in their lives. Fossil trees When a lava flow rolls down the mountain slope it may, and commonly does, meet with a grove or woodland across its path. The varying results of the encounter may be summarized as follows: 1. The forest may be entirely consumed by the lava flow, the trees beaten down and burned, and all trace of the grove wiped out by the rock sheet. This usually happens if the flow is a-a and is quite thick. There is abundant evidence on the slopes of Loa, Kea, and Haleakala to show that hundreds of thousands of acres of beautiful woodland have been obliterated by lava flows within comparatively recent geological time. 2. The flow, if of the pa-hoe-hoe type and moving quite rapidly through the grove, may only destroy the foliage, brushwood, and lesser vegetation. The large tree trunks are resistant even to the great heat of the flow. Moreover, the surface lava cools with such extreme rapidity (this is a noteworthy feature of the Hawaiian lavas) that the radiation from within is relatively slight. In this way large trunks are coated with an envelope or shell of lava which quickly cools and hardens, and forms a protective case, so that the heat from adjacent liquid lava does not reach the tree. The main mass of the lava flows on down the slope, leaving the grove spattered and jacketed with lava. Often great blobs of lava remain clinging to the larger limbs and festooning the summits of the saplings. Remnants of woodlands, exhibiting these phenomena, are not uncommon on the lee slopes of Loa. . 3. The lava flow, acting under conditions like those just de- scribed, but moving more slowly, may ensheath the trees to a con- siderable height, for example, 20 ft. A jacket is formed as has been described, but the gradual incineration of the outer layer of wood results in a space between the tree trunk and the lava jacket. Fresh lava, under pressure, will force its way into this space, and 420 BOTANICAL GAZETTE [NOVEMBER its heat will still further reduce the tree trunk. This process is continued until the tree is wholly consumed and the lava has filled the mold. The main flow passes on, leaving the lava trees behind. The result is a lava pillar or column, 15-25 ft. high, 2-5 ft. in diameter, and often expanded or flaring at the summit, where the trunk branched. These so-called ‘“‘petrified trees” retain many evidences of their arboreal origin, and correspond somewhat in their mode of formation to the petrified trees of the west. In the Puna district, Hawaii, there are hundreds of these lava trees in the wake of ancient pa-hoe-hoe flows. 4. The fourth type of reaction between lava flow and woodland produces deep tubes instead of columns. The flow enters the ‘grove and fills it to a depth of perhaps 20 ft. The rapid sheathing around the trunks of the larger trees protects them, as in the former cases, from immediate destruction. The flow in this instance, however, does not pass on and drain itself from the grove, but remains and solidifies. In the course of time the trunks decay and leave deep tubular vertical pits in the lava. The walls of these tubes are often plainly marked with the impressions of the bark of the trees which they once contained. The tubes are ro in. to 5 ft. in diameter and 15-20 ft. deep. They are known as “tree molds,’ and are abundant on some of the old lava flows, particularly in the vicinity of Kilauea. CoLLEcGE OF Hawatt HoNnoLuLu SPEGAZZINIAN MELIOLA TYPES F. L. STEVENS (WITH PLATES XXIV—XXVI) Through the kindness of Dr. CARLO SPEGAZZINI, I have received recently a number of original packages containing type specimens of Meliola described earlier by Dr. SPEGAzzrNt. In each case the packet bore on the outside copious penciled notes concerning the specimen and careful, delicate drawings of the more significant structures. This collection of types, together with the notes and drawings in particular, are a fine commentary on the work of Dr. SPEGAZZINI. When we remember the large volume of his descrip- tive work and reflect that not only his types but other specimens as well are thus thoroughly and carefully annotated and figured, we are in a position more adequately to recognize the great indebted- ness of mycology to him. The drawings of the present collection have not been published, and in view of the comparative inaccessibility of most of these types, it is desirable that they should be made generally accessible to students by publication. Permission having been received from Dr. Specazzin1, Dr. Alva Peterson has faithfully copied for me, for publication, the most important of the drawings. Such copying was necessary, Owing to the color of the paper upon which the originals were drawn, and the faintness of the penciling, which prohibited direct photo- graphic reproduction. These drawings have been compared by me with the type material and are published herewith with such comments as seem necessary. A permanent celloidin mount* has been made from each specimen and, together with a fragment of the type specimen, is deposited in the herbarium of the University of Illinois. The original specimens have been returned to Dr. SPEGAZZINI at La Plata, Argentine. MELIOLA ARMATA Speg. (fig. 1).—F. Puigg., Pug. I, no. 231; Sacc. 93415. *STEVENS, F. L., Phytopathology 6: 367. 1916. 421] [Botanical Gazette, vol. 64 422 BOTANICAL GAZETTE [NOVEMBER On coriaceous leaves, Myrsine (?), Apiahy, May 1888; no. 2382 (type). The type specimen is heavily overgrown with several parasites. There is considerable variation in the character of the mycelium, which is sometimes straight, sometimes quite crooked. I have not been able to see the mycelial setae around the bases of the perithecia from which this species takes it name. MELIOLA ARGENTINA Speg. (fig. 2).—Fung. Arg., Pug. I, no. 177; Sacc. 1:61. On Cyperaceae, Buenos Aires, February 1880 (type). The mycelium is very characteristic, close, dense, somewhat like M. manca, but distinguished by its very thick mycelial setae, which are striking, being darker and thicker than the mycelium. They are about 15 pw thick at base and over 800» long. The capitate hyphopodia are angular, that is, not smooth or echinulate as shown in fig. 2. The type is heavily overgrown by a Conto- thyrium. MELIOLA BRASILIENSIS Speg. (fig. 3).—Fung. Arg., Pug. IV, No... 116+. Sace. 1566 On leaves of Bignoniaceae (?), Apiahy; no. 1551. (type). The young perithecia are surrounded by an areola of- radiating hyphae. The perithecia also possess short hairs as figured and described by Dr. SPEGAZ- ZINI. MELIOLA CALVA Speg. (fig. 4).—F. Puigg., Pug. I, no. 233; Sacc. 9:414. On Laurinaceae, Apiahy, August 1881 (type). Heavily overgrown with “ Podosporium penicillium Speg.”’ MELIOLA CLAVATISPORA Speg. (fig. 5).—F. Puigg., Pug. 1, no. 241; Sacc. 92422. On leaves of Apocynaceae, Apiahy, April 1881; no. 1701 (type). Perhaps the most striking character is in the sessile, nearly globular capitate hyphopodia. MELIOLA CORONATA Shee. (fig. 6).—F. Guar., Pug. I, no. 175; Sacc. 9:428. On Luchea divaricata, Guarapi, July 1883; no. 3847 (type). The figure shows perithecial hairs to be more conspicuous than they usually are. 1917] | STEVENS—MELIOLA TYPES 423 MELIOLA CRUSTACEA Speg. (fig. n- —F. Puigg., Pug. I, no. 235; Sacc. 92413. On Drymis, Apiahy, 1881 (type). The mycelium forms a compact crustose colony, with the parts decidedly more crowded even than is shown in fig. 7 MELIOLA DECIDUA Speg. (fig. 8).—F. Puigg., Pug. I, no. 240; Sacc. 92426. On Convolvulaceae (?), Apiahy, April 1888; no. 2344 (type). The capitate hyphopodia are very irregularly angular. MELIOLA DELICATULA Speg. (fig. 9).—F. Guar., Pug. II, no. 63; Sacc. 9:415. On Myrisinus, Sierra de Peribebuy, September 15, 1883; no. 3985 (type). MELIOLA ERIOPHORA Speg. (fig. o .—F. Guar., Pug. I, no. 62; Sacc. 92413. On Ficus ibapoy, Paraguay, tiie 1883 (type). MELIOLA GLABRIUSCULA Speg. (fig. 11).—F. Alig. Paul., no. 35; Sacc. 22:48. On Photiniae (?), Agua branca, Sao Paulo (type). MELIOLA GLEDITSCHIAE Speg. (fig. 12).—Myc. Argent. VI, no. 1337. On Gleditschia amorphoidis, Puerto Leon, Missiones, July 1909 ; (type). MELIOLA GUAREAE Speg. (fig. 13).—Myc. Argent. VI, no. 1338. On Guarea balansa, Puerto Leon, Missiones, August 1909 (type). MELIOLA HARIOTI Speg. (fig. 14).—F. Guar. nonn. III, no. 78; Sacc. 11:267; Gaill. Bull. Soc. Myc. Fr. 8:186. 1892. On Bignoniaceae, Paraguay, no. 1291 (type). MELIOLA LEvIpOpA Speg. (fig. 15).—F. Guar. nonn., no. 77 (p. 26); Sacc. 11:264; Bull. Soc. Myc. Fr. 8:181. 1892. On Aspidosperma quebracho, Yaguaron, Paraguay, November 1882; no. 3589 (type). ELIOLA LUDIBUNDA Speg. (fig. 16).—F. Guar. I, no. 178; Sacc. 9:431. On Pilocarpus pinnatus, Paraguay, January 1882; no. 3489 (type). 424 BOTANICAL GAZETTE [NOVEMBER MELIOLA MEGALOSPORA Speg. (fig. 17).—F. Arg., Pug. IV, no,’ 115; Sacc: 1267. On Jodina rhombifolia, January 1888 (type). The very coarse hyphae are quite characteristic. MELIOLA MELASTOMACEARUM Speg. (fig. 18).—F. Puigg., Pug. I, no. 232; Sacc. 92414. On Melastomaceae, no. 2485, Apiahy, May 1888 (type). The mycelium is often less straight than might be assumed from the figure. The oval hyphopodia are characteristic. MELIOLA OBESA Speg. (fig. 19).—F. Guar., Pug. I, no. 179; Sacc. 92421. On Rutaceae, Piragu Bras, July 1883; no. 3834 (type). MELIOLA OBESULA Speg. (fig. 20).—F. Guar. nonn., no. 75; Sacc. 11:262. On Rutaceae, Caa-guaza, Brazil, January 1882; no. 3585 (type). MELIOLA PuiccARt Speg. (fig. 21) ma 3 Puigg., Pug. I, no. 228; Sacc. 92414. On Rubus, Apiahy, May 1888; no. 2722 (type). MELIOLA PULCHELLA Speg. (fig. 22).—F. Puigg., Pug. I, no. 227; Sacc. 9:414. On Myrtaceae, Apiahy, 1881; no. 1699 (type). MELIOLA SAPINDACEARUM (fig. 23).—F. Guar. nonn., III, no. 79; Sacc. 11:266; Bull. Soc. Myc. Fr. 8:184. 1892. On Saindicess. Caa-guazu, Brazil, January 1882; no. 3600. MELIOLA SPEGAZZINIANA Wint. (fig. 24).—F. Guar., Pug. II, no. 64; Sacc. 9:418. On Compositae, Paraguari, March 5, 1883; no. 3751 (type). MELIOLA SORORCULA (fig. 25).—F. Puigg., Pug. I, no. 230; Sacc. 9:418. On Baccharis pingrea, Apiahy, May 1886; no. 2774 (type). MELIOLA SUBCRUSTACEA Speg. (fig. 26).—F. Puigg., Pug. no. 236; Sacc. 93430. Apiahy, 1888; no. 2703 (type). MELIOLA TABERNAEMONTANAE Speg. (ig. 27).—Myc. Argent. VI, no. 1345; Bompland Missiones. BOTANICAL GAZETTE, LXIV PLATE XXIV ae af \WY] FS \ ‘Gg 7 SOD STEVENS on MELIOLA PLATE XXV BOTANICAL GAZETTE, LXIV 6. ———,, Untersuchungen iiber die Chlorophyllkérper und die ihnen homo- logen Gebilde. Jahrb. Wiss. Bot. 16:1-127. ScuMiTz, FR., erties zur Kentniss der Chrotaatophoren. Jahrb. Wiss. Bot. 15:1-175. TIMBERLAKE, H. ss Starck formation in Hydrodictyon utriculatum. Ann. Botany 15:619-634. root. 9. SAMANOSS, S., Hydrodictyon africanum. Bort. GAZ. 55:72-79. 1913. Ps go EXPLANATION OF PLATE XXVII The drawings were made by the aid of the camera lucida, the magnification being X 1040. The abbreviations used are as follows: c, cytoplasm; 7, pyrenoid; n, nucleus; p, plastid; g, starch grain; #, starch grain growing in length toward center of plastid; /, starch grain growing broad at base; s, minute starch grain. Fie. 1. tical section of cell showing relation of cytoplasm, nucleus, and chromatophores, and showing ie chromatophores packed with large Starch grains radiating from pyreno: : Fic. 2.—Optical section of giana ca showing grains of varying width at base. Fic. 3. —Optical section of chromatophore showing grains of varying lengths and grains which vary in width of base as compared with width of outer edge. 434 BOTANICAL GAZETTE [NOVEMBER Fic. 4.—Cross-section of chromatophore showing grains of starch in ioe tape G. 5.—Same as fig. 4. he. 6.—Same a ae a Fic. 7.—Optical section of chromatophore _—e several smaller starch grains in periphery of plastid. Fic. 8.—Optical section of chromatophore showing minute starch grains in periphery of plastid, a pyrenoid of unusual extent and shape, and many starch grains which vary greatly in shape and length. Fic. 9.—Median longitudinal section of chromatophore chawhig several small starch grains. Fic. 1o.—Same as fi . 11.—Cross-section of cell showing chromatophore in cross-section. Fic. 12.—Same as fig. 9. Fic. 13.—Same as fig. 9 14.—Optical section of chromatophore showing another pyrenoid of unusual shape, and starch grains of several different lengths. Fic. 15.—Optical section of chromatophore showing many small starch grains near periphery of plastid, and large grains which differ in shape because of width of bases. Fic. 16.—Same a 15. Fic. 17. etry section of plastid in process of division, showing pyrenoid after it ee divided. . 18.—Optical section of plastid in process of division before pyrenoid has sores division. BOTANICAL GAZETTE, LXIV PLATE XXVII pie a . f BOURQUIN on ZYGNEMA BRIEFER ARTICLES APOGAMY IN PHEGOPTERIS POLYPODIOIDES FEE, OSMUNDA CINNAMOMEA L., O. CLAYTONIANA L. Apogamous embryos developed on prothallia of Phegopteris poly- podtoides Fee, Osmunda cinnamomea L., and O. Claytoniana L. in cultures on Prantl’s and Knop’s full solutions and certain modifications of the Prantl’s solution. About 6 months after the spores had been sown, the first cases of apogamy were observed in cultures of Phegopteris poly- podioides on Prantl’s solution with NH, NO, omitted. The spores from which the prothallia developed had been collected during the summer from a plant growing on a lawn in Ithaca, New York. The plant did not appear in a normal, healthy condition, doubtless owing to the unfavorable conditions under which it was growing. After the spores were sown upon the nutrient solutions, the cultures were placed before an east window, where the conditions of light and temperature were approximately the same for all. Once each week the prothallia were transferred to fresh nutrient solutions. The prothallia, upon which the apogamous embryos developed, were heart-shaped and developed archegonia but no antheridia. The apoga- mous embryo in most cases originated as a slight swelling of the arch- egonial cushion, either on the dorsal or ventral side, at some point near the notch or at the center of the cushion. This swelling gradually increased until a dome-shaped cellular mass was formed, from which the apogamous embryo developed. The parts of the embryo usually appeared in the following order: the leaf or leaves, root, and stem. However, in one case a root appeared before any other member. No foot was formed. In some cases, beside leaves, proliferations, either filamen- tous or slightly expanded at the apices, developed from the cellular mass. October 7, 1916, two series of cultures on the Prantl’s and Knop’s full nutrient solutions and modifications of the Prantl’s solution were made. Fresh spores from the same plant at Ithaca, New York, as well as spores of the same species secured through the kindness of Dr. A. H. GRAVES from Brooklin, Maine, were used. As soon as the spores were sown upon the nutrient solutions, one series was placed in the greenhouse in bright light, while the other series was kept in the laboratory before an east window. The prothallia were not transferred to fresh solutions, but 435] [Botanical Gazette, vol. 64 436 BOTANICAL GAZETTE [NOVEMBER were allowed to remain upon the original solution on which the spores had been sown. A luxuriant growth of algae developed in all of the cultures, which added to the unfavorable growing conditions. March 9g, 1917, in both series of cultures, apogamous embryos were observed on the prothallia which developed in Knop’s full solution from spores collected in Maine. Archegonia were developed on many of the heart-shaped prothallia, while in some of the cultures on the smaller prothallia antheridia were present. Some of the archegonia appeared aborted. In most cases the apogamous embryos developed in the manner which has previously been described. However, a few cases of peculiar development were observed. Miulticellular hairs or outgrowths formed at the base of the first leaf or leaves of the young sporophyte, or at various places on it. On one prothallium a long cylindrical outgrowth several cells in thickness developed from the cellular mass along with the leaves of the apogamous sporophyte. As growth proceeded, this outgrowth broadened out into a one-celled prothallium-like structure, after which it again assumed the cylindrical shape bearing tracheids; at its apex it tended to return to the prothallium structure. On another prothallium an outgrowth which had developed from the notch of the prothallium and projected as a narrow process broadened at the apex, forming a . Slightly notched prothallium. The only cases of apogamy on prothallia developed from spores collected at Ithaca, New York, occurred in the culture of Knop’s full solution which had been kept in the laboratory. Most of the apogamous embryos originated from cellular masses formed on the prothallia, but on one prothallium a cylindrical outgrowth bearing tracheids developed from the cells in the notch. At the apex of this long cylindrical process a cellular mass was formed, from which the leaves, root, and stem of the apogamous embryo developed. Two series of cultures of Osmunda cinnamomea and O. Claytoniana were made at the same time, in the same manner, and placed under the same conditions as the cultures of Phegopteris polypodioides. Apogamous embryos were observed March 9, 1917, on the prothallia in the following solutions: Prantl’s full solution, Prantl’s solution with NH,NO; omitted, and Prantl’s solution with MgSO, omitted. Some of the apogamous embryos developed from cellular masses; others originated as cylindrical outgrowths containing tracheids, from the notch of the prothallia, bear- ing at their apices cellular masses which gave rise to the leaves, root, and stem of the sporophyte. On one prothallium an apogamous sporo- phyte formed near the notch, while at its base a lobe of the prothallium 1917] BRIEFER ARTICLES 437 developed, on which in turn occurred an apogamous embryo. In the latter the root developed first. Only three cases of apogamy were observed in Osmunda Claytoniana in Prantl’s solution with K,SO, omitted. In two cases the sporophytes developed from a mass of cellular tissue, while the third arose as an outgrowth in the notch of the prothallium. A further study will be made of these apogamous forms.—ELizABETH Dorotuy Wuisr, Osborn Botanical Laboratory, Yale University. RAY TRACHEIDS IN QUERCUS ALBA (WITH ONE FIGURE) In the course of a recent study of the medullary rays of the Fagaceae, the writer was impressed with the manner in which some of the fibro- tracheids in Quercus were associated with the rays. It is very common to find the ends of these elements procumbent on the marginal ray cells for a considerable distance and communicating through semi-bordered pits. This condition is so similar to that found in certain coniferous woods that search was made in sections of oak wood at hand for tracheids that were distinctly radial. Fig. 1 shows a marginal ray tracheid of a uniseriate ray in normal stem wood of Quercus alba Linn. Another, somewhat smaller, was found in a different ray in the same section. The location is in the median late wood of the season’s growth and is not in immediate proximity to a large vessel. So far as the writer is aware, ray tracheids have not previously been reported in the woods of the dicotyledons.—SamvuEL J. Recorp, Yale University. CURRENT LITERATURE BOOK REVIEWS Physical chemistry and biology McCLenpon' has performed a valuable service to biologists by organizing the more important facts and principles of physical chemistry that have to do with biological problems. These are stated briefly and concisely, and the usefulness of the book is increased by clearness in definitions. Several passages in the introduction are suggestive of helpful lines of work and interpretation. , The following paragraph from the preface suggests the viewpoint: “The purpose of this book is not to go far into physical chemistry, but to develop a tool for physiological research. Lengthy discussions of debated questions are avoided by tentatively accepting the hypothesis which fits the most facts, until a better one appears. For further discussion of any subject the reader is referred to the literature list and index. For facts, however, he is referred to nature. It is not to be hoped that theories should coincide exactly with data available at present. Even in the most exact branches of chemistry the atomic weight determinations, for instance, do not exactly coincide with the values calculated from the atomic numbers, and there seems to be some doubt as to whether lead is one element or several. How much more uncertainty there should be about physiology, where determinations are vitiated by the great variability of the material and its physiological states.” The book seems to be more from the biological standpoint and much better biology that have come to the attention of the reviewer. In the introduction the author says, “Though the problems considered in this book are physiitogis the methods of attack are chiefly those of the physical chemist.” The book should do much toward encouraging the kind of work and thought that is neither distinctly chemical, in the sense of ignoring the structures and physical environment within which the reactions must take place in organisms, nor yet strictly biological, in the sense of ignoring any of the chemistry involved. When the author states (p. 1) that the methods that may be applied to the interior of living cells are at present very few and concerned chiefly with the inorganic constituents, he is putting entirely too low an estimate on micro- chemistry as a means of investigation. It is true that this is as yet an imperfect — but still it is useful in a great many cases in detecting organic compounds well as inorganic. While his statement that ‘‘modern biochemistry is ee not yet concerned directly with the composition of normal living * McCLENpoN, J. F., Physical chemistry of vital phenomena. For students and investigators in the biological and medical sciences. 8vo. pp. vi+240. figs. 30- Princeton Univ. Press. 1917. 438 1917] CURRENT LITERATURE 439 cells, but with their decomposition products and the exchange between the cell and its surroundings,” and that from our knowledge of these “we may speculate on the composition of the cell and the changes that go on in it during functional activity,” represents two lines along which productive work is being done and will continue to be done, he is leaving in the background a third line which has also proved helpful and promises still more for the future. We might wish that the author had given more recognition to the fact that many plant processes are conditioned by the permeability or impermeabil- ity of non-living plant membranes. These, however, are very minor criticisms on a book which commends itself strongly by its many excellent features. Among the important topics discussed in the introduction are viscosity as a factor in igo ee phenomena, and the relation of semipermeability to electric phenome His pamaaey ‘ the en: membrane (p. 94) as a separate phase which may change with the physiological condition of the cell, and of the protoplasm as sometimes consisting of as many as four phases, in all of which partition solubility must be considered, as well as the molecular condition of each solute in each phase and in the bathing medium, leads him to the conclusion that “all of these factors make the subject of cell permeability a very complex one, no general rules without exception having been found. All we can do at present is to collect data on the permeability of cells to various substances.”’ It is to be hoped that this will commend itself so strongly to biologists that we shall have a larger output of data and a smaller output of theories. The following shortened chapter headings will suggest the general scope of the book: electrolytic dissociation; ne Pere, eee n and hydroxy] ion concentration; surf es, non-electrolytes, and colloids; enzyme action; ceca and its qsnche negative osmosis; anesthesia and narcosis; amoeboid motion, cell division and parthenogenesis; muscular contraction; blood and other cell media. The “chemical summary” in the appendix will be very useful. The literature list includes over 1500 papers arranged alphabetically according to authors. References in the text to this list facilitate more detailed study of any desired topic. Instead of the conventional index to the text, there is an index to this literature list —GrorcE B. Rice. NOTES FOR STUDENTS Taxonomic notes.—BLaAkE? has described a new Rudbeckia (R. Deamit) from atlas closely allied to R. speciosa. Coxer’ has published a detailed and handsomely illustrated monograph of the Amanita group as represented in the eastern part of the United States. 2 Brake, S. F., A new Rudbeckia from Indiana. Rhodora 19:113-115. 1917. 3 Coker, W. C., The Amanitas of the eastern United States. Jour. Elisha Mitchell Sci. Soc. 33:1-88. pls. 69. 1917. 440 BOTANICAL GAZETTE [NOVEMBER He recognizes 7 species in Amanitopsis, although he regards the genus as “artificial and without systematic significance,” separated from Amanita by the absence of a single character. In Amanita, 27 species are described, with full discussion and citation of stations; among them there are 2 new species and 2 new varieties. The numerous plates are unusually good reproduc- tions of fine photographs. ARDNER,! in a first paper on new marine algae from the Pacific Coast, describes, in collaboration with SETCHELL, 9 new species in as many genera. Coriophyllum and Cumagloia are described as new genera. UFFMANS has described a new species in Russula (R. ochroleucoides) and in Stropharia (S. caesiospora) from Tennessee. They are described in connection with a list of fungi collected in Kentucky and Tennessee during September 1916. Macsripe,’ in a revision of the North American species of Amsinckia, recognizes 23 species, 6 of which are described as new. In further notes on a new genus (Twrricula) founded on Nama Parryi Gray, also new species in Phacelia (6) and Miltitzia, 9 new varieties, and numerous new combinations. A new species is also published in Petalostemum, and Gilia virgata and its allies (a group of 5 species) are discussed. In cooperation with Payson, the same author describes new species in Arabis, Dodecatheon, Mertensia, Veronica, Cas- tilleja (2), and Hieracium, all from Idaho; and also revises series MULTIFIDI of Erigeron, recognizing 3 species and 7 varieties, 3 of the varieties being new. STANDLEY,” in a monograph of the Mexican and meee — forms of Ficus, os 41 species, 17 of which are described a WernuaAm; in continuing his studies of the ulus "1 the American tropics, has described Neobertiera and Blandibractea as new genera. He also presents the genus Sipanea, recognizing 10 species and describing 6 a them as new; also 3 new species of Cephalanthus are described.—J. M. C. 4 Garpner, N. L., New Pacific Coast marine algae. I. Univ. Cal. Publ. Bot. 6377-416. pls. 31-35. 1917. ’ Kaurrman, C. H., Tennessee and Kentucky fungi. Mycologia 9:159-166. Igt7. 6 Macsripg, J. Francis, Contrib. Gray Herb. New Series, no. 49. pp. 79- 1917- 7SraNpDLEY, Paut C., The Mexican and Central American species of Ficus. Contrib. U.S. Nat. Herb. 20:1-35. 1917. § Wernuam, H. F., Tropical American Rubiaceae. VIII. Jour. Botany 55:169- 177. IQI7. VOLUME LXIV NUMBER 6 THE BOTANICAL GiaverEre DECEMBER 1917 RESIN SECRETION IN BALSAMORRHIZA SAGITTATA ERNEST CARROLL Faust (WITH PLATES XXVIII-XXXI AND TWO FIGURES) Introduction This problem was undertaken to determine the origin of the secretory tissues and the cause of resin secretion in Balsamorrhiza Sagitiata. The problem was suggested by Professor JosepH E. Kirkwoop, of the State University of Montana, to whom the writer desires to express hearty t thanks for valuable suggestions during the progress of the study. Among the earliest students of secretory organs and their func- tion was MEYEN (13), who stated that “these secretion organs arise from enlarged intercellular passages. One cannot consider them as mere containers, in which the secretion’ is laid by, but one must compare the containers with their contents to inner glands, and the surrounding walls as specialized glands.’’ This writer proposed that the excretory cells surrounding the secretory canals prepare the balsam and then secrete it through the wall into the inter- cellular lumen. That the process is surrounded by a sort of mystic vagueness for MEYEN is evident from the description ‘ wonderful’? which he applied to the process. In his work on the pine MEYEN (14) found resin not only within the secretory passages and the surrounding cells but throughout the entire stem. The opinions of the earliest investigators on resin formation were extremely diversified. KARSTEN, WIGAND, WIESNER, and 441 442 BOTANICAL GAZETTE [DECEMBER others of their school considered resin as a destructive slime forma- tion secreted by the cellulose wall lining the cavity, or else a starch derivative. KArsSTEN (8) was assured of the intimate relation between the wall and resin gum in the wall, because of the obscurity of the cells in ordinary mounts, whereas the walls became extremely clear when treated with alcohol or ether (p. 317). WIGAND (26) considered resins to be entirely out of the category of secretions, for ‘“‘a secretion in our sense is only conceivable as a homogeneous material permeable to the cell wall.”” WreSNER (24) believed the resin masses to be a complex of resin, cellulose, granulose, tannic acid, and “carbonated alkalies,” with the cellulose and granulose as intermediate products. MUELLER (15) and VAN TreEGHEM (22) were unable to find resin in the secretory passages, believing them to be only intercellular spaces. MUELLER was probably the first to use alkannin tincture on dried tissues to test for resin (p. 390). Mayr (12) thought that resin might be secreted by the cells during rapid growth. Undoubtedly the most careful and authoritative contemporary investigator of resin and the problem of its secretion is TSCHIRCH (21), who has given us.a summation of the physiologico-chemical literature of the problem, and in addition valuable evidence con- tributed from his own studies. Tscurrcu’s investigations have convinced him that resins and ethereal oils cannot diffuse through membranes which are water-permeable or water-absorbent. All such secretions, he asserts, remain where they were first laid down. Ecological aspects B. sagittata was first described by Nurrat (16) in 1841. The plant is a very conspicuous feature of the landscape of the prairies and south hill slopes of Wyoming, western Montana, and British Columbia. Its leaves are large, auriculate, densely hairy, growing up from the permanent rootstock in April at 3500 ft. level in west- ern Montana. The flower stocks are plentiful. The flowers are golden yellow with conspicuous heads. They begin to bloom about the middle of May and continue until July, although they reach their maximum bloom during June.. Very soon after fertilization the flower parts wither, and by the time the seeds are mature jn r917] FAUST—RESIN SECRETION 443 late July the flower stocks and heads are brown and dry. The leaves remain green until the first heavy frost, when they soon assume a crackling dryness. The plant is a xerophyte, and is com- monly found on the flats and upland plains, being especially abun- dant on the exposed south slopes of the hills. The writer has observed it frequently as high as 6000 ft. and occasionally in the subalpine areas of a still higher altitude. Specimens of primary rootstock of graduated diameters were dug and dry cleaned and then weighed. They were re-weighed until constant air dry values had been secured. Tables I and II show the results. TABLE I SHOWING WATER CONTENT OF PRIMARY ROOTS COLLECTED JULY 1915; COLLECTION DESIGNATED SERIES I Specimen | I | 2 | 3 | 4 | 5 6 Diameter i min Se 2.5 5 0 hd Weight ty gan 3 0.221 | 1.429 | 1.250] 2.873 | 4.195 | 6.120 Air WEN so 0.088 | 0.648 | 0.585 1.505 | 2.079] 3.002 Percentage loss........... 60.69 | 54.65 | 51.45 | 47.60 | 50.44 | 50.95 Average loss of series, 52.63 per cent. TABLE II SHOWING WATER CONTENT OF PRIMARY ROOTS COLLECTED OCTOBER 1915; COLLECTION DESIGNATED SERIES Specimen | r B 2 | 3 4 5 laweter I WM) os seek cid. s 6.0 9.0 15.0 Weight in QM has oo eos CEN 2.337 | 2-762 | 3-444] 4.144 | 6.425 Pak Gly WEE Ss ro F107)" x L805 4 “2.038 | 3.477 .60 6:30 | 50. 55.70 Average loss of series, 53.60 per cent. Tables I and II show a more uniform correspondence for water content in October than in July, although the average water con- tent is practically the same in both series. In general one may conclude that the size of the root has no definite relation to its water content. Within the slight fluctuation the water content is directly proportional to the weight of the root. Also, the average water content is the same at these different seasons of the year. 444 BOTANICAL GAZETTE [DECEMBER In direct contrast to these data is the record for water content in random soil samples taken from field areas where B. sagittata was growing in abundance. Table III shows such sample records, with normal and air dry weights. TABLE III SHOWING PERCENTAGE OF WATER IN RANDOM SAMPLES OF SOIL IN WHICH B. sagittata GROWS Sample I 2 3 4 5 Weight in gm........... 94.00 126.42 89.27 104. 26 TIO.02 Air dry weight.......... 79.11 103.64 77.56 9Q.12 go.03 Percentage loss......... 15.85 eO:02 2 48.37 4.89 18.18 Average loss of series, 14.46 per cent. Table ITI shows a fluctuation of water content in the soil entirely incommensurate with the constant water values of the rootstocks. This may be accounted for in part by the size of the soil particles, since they, too, are far from uniform, and such differences would cause both a difference in weight of soil per unit mass and a con- sequent difference in capillarity. The fact remains, however, that the plant, irrespective of its root size, selects a relatively constant amount of water from soils that differ noticeably in water content. Calculations were made also to determine the percentage of resin in air dry roots and leaves. The parts selected were first weighed, then placed in pure ether in an air-tight compartment. They were left in this container for a week, during which time they were shaken frequently. This method of extraction was used after it had been ascertained that ether was the best solvent for the resin of this plant. At the end of this time the ether extract was poured off, filtered, and the ether allowed to evaporate at 20° C. until a constant weight had been secured.. For roots dug in July the per- centage of pure resin amounted to 3.3; for roots dug in October the percentage was 3.3; for roots dug in May, some three or four weeks after the,new growth had begun, the percentage was 5.2. This shows a constant resin value during the resting period and an increased resin content for the growing period. The percentage of resin found in the leaves was 9.8. This value was found for leaves" 1917] FAUST—RESIN SECRETION 445 selected and dried in the middle of May, the time of maximum growth. This resin value was found after the ethereal oil had evaporated. By the osmic acid test it was found to contain no fatty oils. An analysis of B. terebinthacea made by Miss HERMA T. KreLLey (19) indicated 9.76 per cent resin, 8.96 per cent of which was removed by chloroform and 0.80 per cent by alcohol. In addition to this there were 5.70 per cent oils, 0.42 per cent _volatile oils, and 5.28 per cent of fixed oils. Lioyp (11) has cal- culated the percentage of resin for Parthenium argentatum, the guayule of the Mexican desert. His values are as follows: Per cent resin PU ek ea ee 2.46 Wood growth of 1907............... a S96 Cortex of ese WOO is ceed re oe an Growth Gt thon. or cee nde 2a 7.56 New growth i 1909 with lekies eae a 2.70 Rata AG Ce ke ey ee .. 10.80 These values were obtained from irrigated plants. WHITTEL- SEY (25) secured from ro to 17 per cent of resin for the field plants of the same species. If the field records are taken, it is evident that by weight the resin content of B. sagittata is smaller than that of the related species, B. terebinthacea, or of Parthenium argentatum. Associated with B. sagittata in a parasitic way is a certain fly of the Typetenid group of the family Muscidae. A complete descrip- tion of this fly will appear in a separate paper now in preparation by the author. The fly is found in the receptacle of the maturing flower head, living there during the grub and pupal stages of its development. The grub is about 1.8 mm. in length by 0.15 mm. diameter, while the pupa averages 1.5 byo.15 mm. Usually there is only one individual to the receptacle, but certain receptacles have been observed by the writer in which 5 or 6 of the parasites lived. The grub is very insidious, ordinarily boring a labyrinthine course through the upper parts of the receptacle and into the bases of the maturing seeds. The result is a twofold injury to the seed: an actual destruction of the maturing seed and a stunt- ing of growth in the seed by intercepting the course of nutrition in the receptacle. , 446 BOTANICAL GAZETTE | [DECEMBER Two other important parasites on B. sagitiata are a nematode and an acarinid. The former is found in the young stem bud before it appears above the ground. The worm eats its way through the bud, mostly in epidermal and cortical tissues, leaving a dry decay behind. Undoubtedly this does much to sap the. vitality of the developing vegetative parts, if not entirely forestalling growth. The mite is found in the sinuses between the leaves, sucking out the juices at the bases of the new leaves. Several hundred were found at times in a single leaf bud. This parasite, too, undoubtedly causes serious damage to the plant and serves to control its abun- dance. Collection and preservation of material The material on which this study is based was collected from July to November 1915 and from April to June 1916. Certain roots, stems, and leaf buds were examined fresh, just after collec- tion. Freehand sections were made and observations taken from water mounts. Other material was allowed to dry and was _ examined as such. However, the greatest part of the material was fixed in various fluids and preserved in alcohol for more detailed examination. Of this last group, material fixed in acid alcohol and preserved in 70 per cent alcohol gave the most satisfactory results. Certain seedlings germinated in the laboratory, illustrating onto- genetic growth, were fixed in Carnoy’s fluid. In addition to free- hand sections of the alcoholic material, sections of typical roots were made 12 u thick in series and similar series of the stem and peduncle 8 uw thick. Sections of seedlings were cut 8 u thick. Various stains were tried, but the most satisfactory combination was acid fuchsin with malachite green counterstain. This combi- nation gave an excellent contrast, since the lignified hadrome and sclerome elements, as well as suberized walls of the Casparian strip, took on a copper green against the fuchsin background. The ordi- nary resin stains, cupric acetate and alkannin tincture, were made use of throughout the study. The alkannin was found extremely satisfactory, since it was both specific and rapid. Osmic acid fumes (osmic anhydride) were used to test for fats. Iodine in potassium iodide was employed for starch testing. Chloriodide of zinc was 1917] FAUST—RESIN SECRETION 447 used to determine the character of the Casparian strip. Slow alco- holic penetration into inulin-testing areas caused a precipitate of this polysaccharide in the shape of sphero-crystals and rhombo- spheres, while a more rapid penetration caused the material to be precipitated in granular and amorphous masses. Resene was tested for im situ by the Mach and Salkowsky-Hesse cholesterol methods (somewhat modified to suit the immediate needs). Crys- tals of resene found in certain cells were positive to these tests. Similar crystals were found as a check in steam-distilled resene, dissolved in alcohol, and allowed to crystallize as the alcohol evapo- rated. A more complete discussion of these tests will be found under tests for resene. The probability of error in resin tests is due in general not to a lack of a specific reagent, but to errors in location of the substance. Due to its solubility in high grades of alcohol it is not impossible that it might become translocated by alcoholic diffusion. Due to its viscous nature it might readily be dislocated in cutting sections from fresh or alcoholic material. The data of certain investigators, among whom are MUELLER (15) and VAN TIEGHEM (22), show no resin in the resin canals, while Santo (18) and TscHtrcH (21) were unable to find the secretion outside of the canals. Errors in tech- nique must have been responsible for this. TscurrcH considered ordinary methods of technique inadequate for the elimination of the error and made use of a method adapted from MUELLER (loc. cit. p. 390). He dried the material at 100° C. for some time before cutting. He then stained with alkannin tincture in water (2 parts of the tincture and 5 parts of water). The former procedure allowed all volatile oils to be driven off and hardened the resin to a tough gummy consistency, so that it was not easily removed from its original position by the section cutter. The latter diluted the tincture so that the resin would not readily dissolve in the alcohol. By this method Tscutrcu was able to demonstrate resin in the form of a dense slime in the canals of Imperatoria Ostruthium, Arnica montana, and in the leaves of Abies pectinata and A. Nor- manni; while the surrounding tissue, especially the secretory cells, was free from resin content. The writer has given due weight to this possible source of error, and has made many preparations from 448 ‘BOTANICAL GAZETTE [DECEMBER live material, alcoholic, and dried preparations. It is only by a study of all these preparations that he feels able to present authori- tative data. Germination tests The seeds of B. sagitiata are ripe about the first week of July. From that time they soon become dislodged from the receptacle and fall to the ground. Between July 6 and July 15, 1915, several thousand seeds were collected and sorted into two tentative groups, those considered viable and those considered non-viable. ‘The latter group comprised about 90 per cent of the whole. Of this non-viable group almost half were eaten at the base of the seed by the Typetenid parasite, and the remainder were small and shriveled, due to lack of nourishment. This non-viable group was discarded. Of the seeds saved, 100 choice ones were selected October 19, 1915, and . weighed. Their total net weight was 1.041 gm. They were then soaked in concentrated sulphuric acid for 8 minutes, carefully rinsed in distilled water several times, and placed in a sterile moist chamber at about 30° C. during the test. The record is as follows: SERIES I October 19; I00 ti ein: seeds weighed, sterilized, and set to germinate in sterile moist c November 3; one oe aid beginning to burst testa; hypocotyl protruding. November 5; 3 seeds burst testa; hypocotyl of one 11 mm. long. November 6; 13 seeds found soft and decaying; thrown out. November 10; 11 seeds found soft and discarded. November 11; 5 seeds germinating; 4 thrown off testa. November 12; 12 seeds found soft and thrown out. November 14; 8 seeds germinating. November 17; mold developing; those seeds not yet germinating but con- sidered sound rinsed in weak formalin solution, then thoroughly rinsed in dis- tilled water. November 28; ro seeds germinating; 5 of these fixed in Carnoy’s fluid, 5 transferred to cork supports in beakers of water and allowed to continue growth; all ungerminated seeds discarded Later, no further growth SERIES It November 18; 100 seeds selected, soaked in sulphuric acid for 5 minutes, thoroughly rinsed, and set to germinate between damp filter paper in chamber as in Series I; average temperature 30° C 1917] FAUST—RESIN SECRETION . 449 November 28; mold developing; seeds rinsed in formalin solution, rinsed in distilled water, and returned to damp chamber. December 1; culture found dry; had been dry about two hours. No germination in this series. SERIES III January 25; 100 seeds selected, soaked in sulphuric acid, thoroughly rinsed in distilled water, then placed in sterile moist chamber between filter paper; distilled water supplied as needed drop by drop by siphon apparatus; temperature 25° C, January 31; first seed bursts testa; no mold. February 1; 5 seeds found soft wid discarded. February 10; 3 seeds germinating. February 18; 4 seeds germinating. February 24; 6 seeds germinating; no mold. February 29; 8 seeds germinating; several of the remainder soft, discarded. March 4; seeds dry for several hours; no subsequent germination. An examination of these records shows certain interesting and significant points. A comparatively small percentage of seedlings germinated from selected seeds, due to lack of viability in appar- ently viable seeds and to infection during the germination tests. An extremely small percentage of seeds germinated from the total seed production. Seriés I gave a total of 10 per cent of seeds ger- minated from too selected seeds. Series II gave no germination, due to desiccation antecedent to expected germination. Series III gave an 8 per cent germination within the same time limit as Series I (less one day), but at a lower average temperature. The average for Series I and III is 9 per cent. A more elaborate and critical study of the germination values for Parthenium argentatum by Ki1rxk- Woop (9, p. 39) gave 10.8 per cent for selected seeds of that species. Since the selected seeds comprised only about one-tenth of the total seeds produced, an average of less than 1 per cent (0.9) is obtained for the ratio of seeds germinated to the total of seeds pro- duced. Although the plant is a perennial, the severity of the winters in the exposed places where the plant grows kills out many of the rootstocks. Taking into consideration the infection of the bud and the stem by nematodes and mites, an enormous seed pro- — duction would seem necessary to maintain the plant as the domi- nant member of the society in which it grows. 450° BOTANICAL GAZETTE [DECEMBER 'A survey of field plants was made during May 1916. Plots covering areas 300 ft. square were studied, and the number of root- stocks counted and the seedlings in those areas listed. For two such plots about 800 plants were found, equally divided between the two plots. This number comprised all plants of B. sagittata of all sizes and ages within the plots. An accurate idea of the distri- bution of the plants is seen in text fig. 1. Areas 4 ft. in radius were Fic. 1—Field of Balsamorrhiza sagittata in vicinity of Missoula, Montana, in May 1916. closely inspected around each plant, the plants receiving numbers as the listing progressed. In plot 1, in the count of the first 100 plants, one seedling each was found for numbers 2, 3, 4, 8, and 100, no other plant having the seedling within this radius. In plot 2, for the first 100 plants counted, numbers 11, 49, 69, and 70 had one seedling each, while number 68 had two. In a second 100 in plot 2, numbers 41, 61, and g1 had one seedling each. Of those plants observed about half had borne seeds the previous year, Or 1917] FAUST—RESIN SECRETION 451 about 200 per plot of 300 square ft. had been seed producers. Yet only 5 seedlings were found in the count in plot 1, only 6 in the first count in plot 2, and only 3 in the second count in plot 2, aver- aging 4.66 per cent, a much lower average secured than for seeds germinated indoors. It is evident from the dominance of this species in the society in which it lives that it depends largely upon the continued growth from the rootstock from year to year for maintenance of its dominance. It is not unusual for the individual rootstock to produce 100-300 seeds. This would more than replace the plant each year if the laboratory germination test were effective in the field, but the lower germination record for field plants indi- cated beyond a doubt that the plant could not be replaced each year by the new seedlings. The germination in the field is comparatively late. The first of the consocies to germinate is the seed of Lupinus ornatus, which begins about March 1. Since B. sagittata does not fruit until the third or fourth year, but gives up all the time and energy the first two years to growth and food storage, it is evident that early ger- mination is not essential to the best interests of the plant; yet the blooming rootstocks of B. sagitatta are in flower long before the lupine. Of the factors determining germination, air (oxygen) is un- doubtedly the most important. A test of this factor was made in a group of seeds not included in the series just cited. The same conditions prevailed in this series as in the recorded series, except that they were covered with a sterile crystallizing dish so as to exclude air. There was no germination. A careful comparison with the recorded series seems to indicate that oxygen is more necessary to prevent fungous growth than as a factor in the meta- bolic processes of germination per se. When seeds are once set to germinate, moisture is constantly necessary for germination, as indicated in Series II and III. The temperature coefficient of germination is interesting. It is evident that germination is more rapid at first at 30° than at a lower temperature. However, although germination at 25° is slower, that appears to be a more advantageous condition, since at that point a maximum growth of the plant is effected for a ee BOTANICAL GAZETTE [DECEMBER minimum growth of fungus. Undoubtedly under field conditions the temperature is constantly less than 25° C., except for a short time during the warm afternoons. In fact, practically any night during the germination period (middle of April to middle of May) a freezing temperature may be recorded. Certain seeds which actually germinated or commenced to ger- minate had been injured in the region of the root cap or even in the region of the meristem of the root. This was the cause of a decreased vitality in the entire plant and was often the occasion for rapid bacterial infection. This injury was originally due to the Typetenid parasite in the receptacle of the flower head. Such an injury must be a source of constant decay to germinating seeds in wet ground. Structure Roor.—In the developing seedling of B. sagittata at a very early stage, a day or so after the seedling begins to break through the testa, certain cells begin to differentiate into protoxylem. These occur at four angles of the root section, forming a tetragon, giving rise to the tetrarch structure of the primary root. At first these spiral tubes develop singly, but may later be followed by one or two others centripetally at each angle of the tetragon (fig. 7). As might be expected from their later origin, these secondary spiral vessels are somewhat larger than the elementary vessels. At this earliest differentiation of protoxylem there are no indications of protophloem from procambium. Very soon, however, such differ- entiation begins midway and slightly centrifugal to the line joining the first quartet of protoxylem elements (fig. 8). The procambium cells in this region divide tangentially, with apparent irregularity, developing protophloem externally and at the same time inter- mediate protoxylem internally. Such growth is represented in figs.g and 10. These periclinal divisions continue until 4 or 5 con- centric rows of phloem are formed and until the xylem almost com- pletely envelops the axial plate. At this time the axial plate is still composed of undifferentiated tissue quite irregular in contour, strikingly similar to the stem pith of the plant. The leptome strands are limited externally by the undulating endodermis, con- 1917] FAUST—RESIN SECRETION 453 spicuous now (fig. 10) by anticlinal suberization. The appearance of the thickenings is knotlike or looplike along the radial walls. The endodermis, unlike that of Parthenium argentatum, contains “no starch grains such as commonly occur in higher plants. The secondary xylem contains not only well defined spiral vessels and tracheids, but vessels of intermediate type. For instance, in fig. 11, ¢ and d with bifurcating spiral reinforcements are not far removed from a, the true spiral type, while e more nearly approaches the eyelet type so characteristic of the tracheids. In the dicotyledons the usual type of axial structure is par- enchymatous; but such is not the case in B. sagittata, for there the wood elements soon work centripetally, crowding against the origi- nal plate cells. The latter become sclerified, so that the plate becomes a solid disk of vessels and sclerome. Such sclerification begins before radial suberization of the endodermis and consider- ably earlier than resin duct formation. The centripetal crowding with the addition of the new xylem elements increases the actual size of the region within the cambial ring. The suberized endodermis serves a twofold purpose. The suber- ization thickens the walls and allows the endodermis to act as a . supporting girdle, and, in addition, acts as an impervious barrier against an external translocation of food material. Russow (17) has described two types of suberization of endodermis, that in which the radial and one tangential walls are thickened (his ““C”’ type), and that in which the entire wall is thickened on all sides (his “O” type). HABERLANDT (6, p. 372) suggests that such dis- tinction is not of great mechanical importance, since variations may occur within the same genus, such as Carex, Smilax, etc. Although the ‘‘C” type is the most usual in B. sagittata, there also occurs the “‘O”’ type, and in woody secondary roots a thickening which may be designated as an ““H”’ type (fig. 12). In the primary root of 5 mm. or over, the suberized endodermis is interrupted in regions between resin canals by phloem strands which cross into the cortex in these regions, leaving open an avenue for translocation of materials in these special places (fig. 13, ph). The origin and development of the resin canals will be discussed later in this paper. 454 BOTANICAL GAZETTE [DECEMBER In the older rootstocks of two or more years’ growth three regions may be distinguished, a basal primary root, a median swollen region, and two or more branched root growths above the swelling. From the upper reaches of these proximal root branches arise the aerial portions of the plant system. The lowest root region is characterized by a single row of resin canals and an axial - stele, while both of the other parts have two concentric rows of resin canals (fig. 14). Cross rays connect these longitudinal canals at frequent intervals. These old rootstocks are further character- ized by lysigenous splitting of the now functionless rays, so that the wood is split apart in almost every ray region (fig. 15, /:, 1,). This cracking is probably caused by tension in the wood areas and a shrinking of the cells in the near vicinity. The subsidiary root system of B. sagittata varies from the main system in that it is diarch in type. The protoxylem first becomes differentiated as two groups at opposite poles, with evidence of protophloem developing intermediately (fig. 16). By the time the suberization of the endodermis occurs, intermediate wood elements have developed and the axial plate is well sclerified (fig. 17). It is not until considerably later that the resin ducts arise (fig. 18). The root of the plant has a rather large wood area compared with the extra-cambial portion of the root. Table IV shows that it is practically a ratio of two to one through all stages of secondary thickening. TABLE IV Number Diameter of root Ratio Risk ke we w he aes | mm. pe BoP gin so, ware 2 °§ 2° Boncy ae ees 4.5 art Bee: ease 12 8:5 ae ogre ata a! 12 at This excess of wood tissue may be accounted for by the area occupied by the rays extending between the wood elements. In no. 5, with two rows of resin canals, lysigenous cracks in the ray region occupy about half of the wood area. While the tracheids conform to the usual type for Compositae and the phloem cells show no unusual ‘characteristics, certain 1917] FAUST—RESIN SECRETION 455 features of the stone cells deserve special consideration. These cells are found principally in the hypodermal region and give a hardness to the cortex, which makes untreated material difficult to section. They take on a vivid green with the malachite stain. They are somewhat larger than the surrounding cortical paren- chyma, due to their thickenings. In surface view they present a polygonal appearance, with bluntly rounded corners (fig. 19, a—d). A view at the edge of the cell shows circular pores which enlarge and approach one another as they invade the center of the cell. The center of the cell is an irregular space devoid of the sclerified material, usually filled with ordinary parenchyma cell protoplasm. This content fails to react to starch, oil, or resin tests. As the canals of the cells near the lumen, they anastomose in pairs or triplets, giving an appearance as shown in fig. 19,d. The cells have at least one transverse diameter longer than the longitudinal (com- pare fig. 19, c with d). This same type of stone cells also occurs in the axial plate of old woody roots (both primary and secondary), and in the wood of subsequent formation, although it is never found in phloem regions. In the latter tissues it is supplanted by bast strands (fig. 13). The stone cells usually occur in groups of five or six. STEM AND PEDUNCLE.—The hypocotyledonary stem contains the tetrarch arrangement, as shown in fig. 20. The phloem is exarch - and the xylem endarch, with protoxylem innermost. As progress is made up the stem, the meristematic region where the bud resides is approached, containing secondary stem, leaf, and flower structure. At this place the four main strands each give off two anastomosing bundle strands to the bud, while the major portion of the bundle strands continues into the cotyledonary collar (fig. 21). Slightly above the section diagrammed in this figure certain changes occur in the bundle strands. These are best illustrated by a comparison of the section shown in fig. 22 with fig. 24, a diagram of the course of the bundles, seen longitudinally. Between levels cc and dd strands are given off from w and x, which unite above dd to form a median strand ~. Coincidentally laterals from y and z form the median strand s. Similarly above the section dd, x and y, z and w, give off subsidiary strands which anastomose in pairs to form respectively 456 BOTANICAL GAZETTE , [DECEMBER yr and ¢. A section taken between cc and dd might show all the way from 4 to 12 strands, depending entirely upon the exact level of the section, and a section taken above dd might show from 6 to 8 for the same reason. Slight variations in the origin of coincident laterals due to unequal nourishment would be shown in an odd number of traces. Returning to figs. 20-23, diagram 22 occurs about the level dd. Laterals from w and x have been given off to form p, but have not yet anastomosed. A lateral from z to form s has been separated from the parent bundle, but its mate from y is still intact within y. Meanwhile traces from x and z have already arisen for the formation of r and /, although their mates are still within the main bundles w and y. Hence the actual derivations are atypical in location, although the end results are the same, that is, 4 median strands (9, r, s, ¢) derived from uniting limbs of the 4 original bundles (w, x,y,z). The section in fig. 23 shows a level above dd, where laterals are being derived from ¢ and w, y and $s, y and r, to form strands of tertiary rank, with laterals from w and p not yet derived. Already x and z have been broken up by a twofold bifurcation. ‘ Certain atypical traces were found in the study of the tissues of B. sagittata at this period in its development. In one series of sec- tions the laterals from x and # received a trace from below. Further observation showed this trace to end blindly at a lower level. In another series the lateral from z to s was found to give back certain strands to z before the lateral united with its mate from y. In such cases transverse sections alone would be difficult to use in tracing such bundle anatomy. In older stems and in the peduncle 8-24 traces are derived, dependent on the amount of conduction required in these parts. Lear.—The leaf type of a-seedling is defined with reference to the number of traces in the blade which appear as separate entities at the origin of the leaf blade from the petiole. In his studies on some 50 seedlings of representative groups of Compositae LEE (10) has chosen Silphium perfoliatum as the type for Heliantheae, to which tribe B. sagittata belongs. The general superficial appear- ance of S. perfoliatum and the plant under consideration is very similar. Both seedlings are large and hardy, with no secondary 1917] FAUST—RESIN SECRETION 457 roots up to this period of development. In writing about the bundle strands of this type LEE states as follows: As usual in this order the single vascular bundle at the apex of the coty- ledon first divides into 3, after which, in correspondence with the large size of the cotyledons, each main strand gives off a large number of smaller bundles. At a lower level, these begin to re-fuse with the larger strands, and at the base of each cotyledon only 5 vascular strands remain, a large-median one and two smaller laterals on either side. In the pronounced cotyledonary tube the extreme lateral and smallest bundles fuse with the corresponding bundles from the other cotyledon, and the composite structure produced, after decreasing in size, moves around and joins on to one of the remaining strands. At a still lower level in the cotyledonary tube, the remaining lateral bundles fuse in pairs, so that 4 canal vascular strands enter the hypocotyl. Upon examination of seedlings of B. sagittata it is evident that neither the cotyledons (figs. 22-24) nor the first true leaf (fig. 6) possess bundle traces exactly corresponding to the type for the Heliantheae. There are considerably more than 5 strands for the region above the origin of the blade (fig. 23), but at a level just below the cotyledons in the cotyledonary collar (fig. 24, level dd) only 6 strands are found, ‘although in certain sections even below this level (fig. 22) a greater number is indicated, due to peculiarities of transverse anastomoses. Even the true leaf (fig. 6) shows only 3 bundle strands at the origin of the blade from the petiole. It may be said, therefore, that for B. sagittata we have a type of bundle anatomy of somewhat fewer strands than for Silphium perfoliatum. With these exceptions it has a general resemblance to the tetrarch anatomy of the Heliantheae. RESINIFEROUS DUCTs.—A root of a young seedling with coty- ledons not yet outspread shows clearly the resin secretion from the protoxylem outward through the cortex. There are large drops of resin at the time the endodermis begins to take on suberized thick- enings, yet at this stage no resin ducts have formed. Not until the seedling is somé 60 days old do the ducts begin to form in the root. The development, although surely determinetl beforehand, does not occur until after resin formation. The method of development is schizogenous. First a periclinal division occurs in the endodermal cell opposite a group of tracheids. This is followed by an anticlinal division, so that 4 cells arise from the original endodermal cell 458 BOTANICAL GAZETTE [DECEMBER (fig. 26). A lumen develops in the midst of the 4 cells, which canal becomes the cavity for resin secretion. Usually the 4 cells now divide obliquely with new planes of division parallel to the walls of the duct, so that the duct becomes lined with 2 layers of cells (figs. 27, 28). A consequent cleavage at right angles to the walls of the duct gives rise to 8 cells immediately lining the duct (figs. 29, 30). This ring of ducts in the cortex, just outside the endo- dermis, is the usual complement of ducts for the root. As the root grows, however, room is made between the older ducts and new ones are formed. The resin ducts of the root are continuous from the basal region to the junction of the root with the stem. These ducts are somewhat more undulatory than are the tracheids. At times there is evidence of the fusion of 2 ducts, but this is merely due to a breaking down of internal processes from the cells surrounding the lumen rather than an anastomosis. An examination of seedlings of 2 mm. or over shows in the hypocotyl 2 concentric series of resin canals, the outer series con- tinuous down through the entire root system, and the inner merely potential in the younger seedlings. The 2 series are connected by radial canals between the longitudinal lumina of the series and by transverse canals between consecutive longitudinal canals of the same ring (fig. 31). Moreover, the inner series is capable of ventral extension in roots of one year or over, so that they extend down and around the median enlargement of the root. At this place they all anastomose in a common center (fig. 14). This type of concentric rings with radial anastomoses corre- sponds to observations made by Catvert and Boop1e (2) for Manihot Glaziovii, but is the reverse of Ltoyp’s (11) observations on Parthenium argentatum. The ducts in the stem consist of 2 separate systems. These systems have similar origin and structure, but different location. One series is found in the pith opposite the wood of the bundles, while the other series occurs in the cortex opposite the interfas- cicular region, almost within the interstices between the phloem 0 the bundles (fig. 25). These ducts arise somewhat earlier than those of the root and apparently are not connected with those of the root system in any way. They are continuous throughout the 1917] FAUST—RESIN SECRETION i 459 entire stem, although they are intercepted in certain regions by processes from the lining cells, as shown in fig. 35. The origin of both these systems in the stem is schizogenous and follows the Same sequence of development as outlined for the duct system of the root. Hotm (7), working on the anatomy of Solidago odora (pp. 252-254), quotes VAN TIEGHEM as saying that resin ducts have only been observed in the cortex (primary) “in certain species of Solidago, including Kleinia; otherwise these ducts are frequent in the pith and in the secondary tissues.”’ The two series of ducts in the stem of B. sagittata indicate a composite type of duct anatomy, in that they supply a duct system in the primary cortex, hitherto observed only in species of Solidago, and in addition supply the usual system of the pith. These ducts, too, are subsequent to resin formation in the stem. The resin ducts of the leaf are merely upward prolongations of the stem systems, corresponding to the bundle trace relationships already indicated.. For each bundle in the leaf there are two canals, one occurring on the upper side of the leaf and the other one on the lower side opposite the hadrome elements. DEBARy (4) gave a very complete table of the duct systems as far as they had been worked out in his day, VILLUEMIN (23) has studied it in certain species, and Cot (3) has added to the knowledge of the subject, but a thorough revision of the literature needs to be made in order to bring the knowledge up to date. Since VAN TIEGHEM prepared his schematic outline for types of resin duct distribution in the stems of Compositae, at least two new types have been observed, namely, the Solidago type described by Hotm (7) and the type represented by B. sagittata, described in this paper. For this reason it is necessary to recon- struct VAN TieGHEM’s scheme to include the more recent observations. OUTLINE KEY TO SECRETORY PASSAGES IN STEMS OF COMPOSITAE TYPES I, Stem containing passages within bundle sheath . Passages confined entirely to medullary region. ...Ageratum conyzoides B. Passages both within and without bundle stran 1. Only one medullary passage for each leaf sae bundle a) One medullary and one cortical passage 460 BOTANICAL GAZETTE [DECEMBER i. Both passages opposite the bundle....... Solidago limonifolia ii. Medullary passage opposite the bundle, but cortical passage in the interstices between bundles . . Balsamorrhiza sagittata b) One medullary and several cortical passages Serratula centauroides 2. A group of medullary passages for each group of cortical ones Gren Comibaet oo ie be ae arduus pycnocephalus b) Groups in curved series................... Helianthus tuberosus II. Passages wholly without bundle strands A. Passages external; not walled in on inner side by endodermis or ON ais gis i ke PG As Vane Solidago odora B. Wall of passages partially formed by endodermis or pericycle 1. Passages single, not in grou a) One passage in middle at outer margin of each main leaf ORG a ee ee eee ee Senecio vulgaris b) One passage in middle of outer margin of each main leaf trace; in addition one passage for each single bundle in A MT A AP a a i ee he ster sp. c) One passage on each side close to phloem of each main eeied WER ee ee ee Tagetes patula 2. Passages in a) Three to ns passages opposite outer margin of phloem and of minin Dene oie ie Silybum marianum Physiology of resin secretion Numerous theories have been proposed to explain the origin of resin and the methods of resin secretion. Among the more impor- tant sources conceived as a basis for resin formation may be named the following: starch, cellulose, tannic acid, phloroglucin, a hypo- thetical glucoside, terpene, and even chlorophyll. As diversified as are these substances, there may be at least superficial reasons for relating resin to any one of them. However, only a deeper analysis of the problem, following out a particular coincidence of resin and one of these materials, will show whether the relationship is a genetic one or not. Evidence is here presented showing certain relation- ships of the resin secreted by B. sagittata. The resin of this plant appears as a viscous exudation, especially from newly dug roots. It is a light lemon color in smaller quan- tities, but in larger amounts (ether extraction) it appears a golden yellow. It contains a small amount of essential oil, but gives no 1917] FAUST—RESIN SECRETION 461 tests for fatty oils. In the roots of young plants (two years or less) it is found mostly in the outer ring of canals, while in old roots it occurs in the two concentric rings of canals, together with the radial anastomoses. As has previously been mentioned, the ordinary resin tests are cupric acetate and alkannin tincture. The acetate requires several days and imparts a brilliant emerald to the resin. The alkannin causes the resin to take on a brilliant crimson in a very short time. The resin may be distinguished from oils of a fatty nature by the osmic anhydride test. The alkannin is much more soluble in the higher grades of alcohol, but such a high concentration of the solvent is not desirable, since it also acts as a ready solvent for the resin. The Tscurrcu test for resin, modified from MUELLER, was used by Tscuircu for demonstrating that resin was present in the lumina of canals of Imperatorium Ostruthium, Arnica montana, Abies pec- tinata, and A. Normanni. In fact, TscutrcH noted a layer of slime among all schizogenously formed canals. The writer has made use of this technique for testing resin in B. sagittata and Parthenium argentatum. These preparations show resin in the canals, as described by Tscutrcu, but in addition demonstrate resin in the newly formed xylem, an abundance of it in rays and inner regions of cortex, including the cells immediately surrounding the canals, and great masses of resin in the cambium. Such dry preparations demonstrate resin in the identical locations as the aqueous mounts from fresh material and alcoholic material. In this wise an accurate check has been secured on the demonstration mounts. An analysis was then made to discover the approximate relation of resin to other organic materials. Resins are classified according to their reactions to four kinds of tests: resino-tannol, resene, resiniferous oil, and resinic acid tests. The resino-tannols are those resiniferous materials which react to tannin tests. For example, when ferric chloride is added to a solution of resino-tannol, iron tannate is formed as a precipitate. Other reagents used to test this relationship are potassium bichro- mate, lead acetate, potassium hydrate in alcoholic solution, and nitric acid. Should any of these reagents give a positive test, an exceedingly difficult problem would then confront the investigator. 462 BOTANICAL GAZETTE [DECEMBER Since tannin is not a single compound, but a convenient name for a related group of compounds, separate tests of the entire group would then be necessary. Moreover, as Tscutrcu has pointed out (loc. cit. 1142), such a test would not necessarily prove a genetic relationship, since tannin might be merely a en and not its source. Samples of the resin (ether eetractiod) from B. sagittata were submitted to the resino-tannol tests. All samples gave negative test except the one where nitric acid was used as the reagent, in which case the test was atypical. This test was so positive, how- ever, that it served to indicate a possible relationship of another nature. Two or three drops of the pure resin were placed in con- centrated nitric acid. The resin globules became dark brown, with a violent evolution of nitric oxide in the course of two minutes, accompanied by the formation of a cellulose membrane across the top of the solution. When heated, this membrane burned with a warm yellow flame and heavy smoke, leaving a black char. The odor was like that of burning celluloid. The test was then repeated with resin dissolved in 95 per cent alcohol. The reaction was delayed, not taking place for 5 minutes, but was accompanied by a more violent evolution of the gas. When the test was repeated with the resin dissolved in absolute alcohol, the test reaction did not take place for 6 minutes, and was even more violent than on either of the previous occasions. Such a reaction would indicate a relationship to cellulose or other carbohydrate. The second group of resins are called resenes. They are the ones showing kinship to the terpenes and the fatty aldehydes. The modified cholesterol tests are applied to these substances. Two of the more common and specific ones are the Salkowsky-Hesse and Mach reactions. In the Salkowsky-Hesse test 0.002-0.003 gm. of the resin is placed in 3 cc. of chloroform and shaken with 3 cc. of concentrated sulphuric acid. The chloroform solution is then evaporated in a porcelain dish and the color of the residue noted. The color differs for various known resenes, from orange through lavender to blue, but is always a constant index for a particular resene. Substances that are not resenes do not give such color tests. In the Mach tests 0.003 gm. of the resin is placed in 1 Cc. 1917] FAUST—RESIN SECRETION 463 of concentrated hydrochloric acid and evaporated in a porcelain dish and the residue washed. If the test is positive, the residue is usually blood orange or red. Both the Salkowsky-Hesse and the Mach tests were applied to the July and October resin of the Balsamorrhiza. The results were negative. As previously described, the fatty oil test is made with osmic acid. A slide with a thin smear of the resin is inverted over a solution of the acid or of the crystals. The fumes of the reagent cause fatty substances to blacken. When the osmic anhydride was applied to resin of B. sagittata, no positive test was secured, even after prolonged application. If resin gives an acid reaction to litmus or requires several por- tions of one-tenth normal sodium hydrate to neutralize, it is said to bea resinic acid. Such acids unite with ammonium hydrate and the hydrates of the alkali metals to form unstable resinic esters. A great number of these resinic acids are known, although their chemical formulae have been worked out only empirically. Certain of these acids have been distinguished by the type of ester formed with ammonium hydrate. For example, the group to which pimar acid belongs builds a very beautiful acid ammonium salt, while the group to which abietic acid belongs forms with ammonium hydrate a non-crystalline gelatinous emulsion (see TscHiRcH, Joc. cit. 519). The resin of B. sagitiata gives a very decided acid test. It com- bines with ammonium hydrate, potassium hydrate, and sodium hydrate to form resinic esters. Moreover, the ammonium ester is an emulsoid. The evidence gained from these tests shows that the resin of B. sagittata is a member of the resinic acid group, giving an ester with ammonium hydrate similar to that of abietic acid, and that it has certain relationships to carbohydrates in that it forms a nitro- cellulose when reacted upon by nitric acid. It was found that by a distillation of the resinic acid, either from the gross plant structure or from ether extracted resin, in the presence of steam, an entirely new product was formed. The substance had a tendency to crystallize upon cooling below 25°, and gave off a very characteristic pungent odor, sweetish, but very irritating to the mucous membrane. The substance was white, opaque, and 464 BOTANICAL GAZETTE [DECEMBER crystallized out of water in a very elaborate form, simulating frost crystals. Later it was found that it crystallized as long monoclines out of alcohol or ether. The two resene tests were applied to this substance, with positive results in both cases. SALKOWSKY-HESSE TEST Sulphuric acid solution after shaking: golden yellow. Chloroform solution before evaporation: pale yellow, nearly colorless. Residue after evaporation of chloroform in porcelain dish: first, bright yellow; later, rich dark brown; red brown; ending in deep violet. No fluorescence. MACH TEST Color of residue from evaporation of alcoholic solution of resin with hydro- chloric acid and ferric chloride: dark re This resene is saturated, failing to absorb iodine, but is weakly acid. These positive tests, together with the general physical prop- erties of the substance, were proof that the material under analysis was a resene, a type of fatty aldehyde. It was further discovered that all of the resinic acid was converted into resene in the process of steam distillation. Two preparations of resene from steam distillation of spring roots were made during August 1916. One of these was placed in a glass-stoppered bottle and the other in a loosely corked vial. An examination after 6 months showed that the former preparation was in the original crystalline state, while the latter had been con- verted into a lemon-colored resin, and had completely lost its crystalline structure. This fact supports the view that the resene had been converted into resinic acid by an oxidative process, such as holds true for terpenes in general. This process follows the natural method expected in the plant tissues, and is the reverse of the reduction process in the presence of steam. The discovery that resene is derived from resinic acid gave rise to the inquiry as to whether resene might not be found in the Balsamorrhiza plant; in short, whether there might not be a genetic connection between the two substances in the plant itself. The _ following methods were carried out in this inquiry: modified resene tests en bloc and modified Mach tests applied microchemically. * 1917] FAUST—RESIN SECRETION 465 In the tests en bloc equal portions of Balsamorrhiza roots (alco- holic preservation of August material) and sprouting stem buds (fresh March material) were each placed in 5 cc. of chloroform and left for two days. The plant tissues were then removed and 5 cc. of sulphuric acid added, according to the Salkowsky-Hesse method, and the mixture thoroughly shaken. The results are given in table V. TABLE V | August root | March bud Sulphuric acid solution.................. Pale tan Colorless — Cionotorin sobitiog 9c. cet cs < Colorless Colorless Residue from evaporation............... Colorless Lavender to violet MINGPRCPNES 5d oa a None Marked entices eiction The Mach test (modified) was used on sections of rapidly grow- ing stem buds, just previously placed in 85 per cent alcohol. Sec- tions of this material were cut in 95 per cent alcohol; 1 cc. of this alcohol, 1 cc. of ferric chloride, and 1 cc. of hydrochloric acid were mixed and the sections transferred to this mixture on a depression slide. The slide was then gently heated until the mixture was reduced to about rcc. Even from gross inspection a typical Mach test was produced in the vascular tissues. Examination under low power of the microscope showed reactions in the following places: heavy stain in the cambium and rays (identical with regions testing heavily for resin in fall tissues); specially marked test against walls of endodermis facing cortex; all through cortex and pith to more or less degree. In the heavily testing regions masses of monoclinic crystals were found, deeply impregnated with the stain from sur- rounding crystals that had dissolved (fig. 37). This same test was applied to roots of the August collection, preserved in 60 per cent alcohol. The results of the test were negative. This very specimen block had been used previously for resin tests and had yielded a decided resin test in the vascular and conductive areas. These two tests, the Salkowsky-Hesse and Mach, modified to meet the needs of the material under investigation, applied to Balsamorrhiza material, showed a negative test for fall roots and 466 BOTANICAL GAZETTE [DECEMBER a uniquely strong ‘positive test for the spring bud region. In fact, a comparison of the former test with the present one would indicate a much higher percentage of the resene in the spring bud than was necessary for a test reaction. Moreover, the Mach test both checked up the results obtained in the Salkowsky-Hesse re- action and gave the precise location of the resene in the grow- ing bud. A final test to check up the previous determinations consisted in placing some of the material of the fall collection and the spring collection in absolute alcohol-ether, half and half, for a period of two days, then allowing the filtered solution to evaporate. No crystals were found from a careful examination of the fall roots, yet an abundance of crystals of the monoclinic type were secured from the spring stem material. The evidence secured from these reactions for tissues of B. sagit- tata shows (1) that resene is found in the growing plant tissues, in the meristem and conductive areas; (2) that resene is found in the same region in spring tissues where resinic acid is found in the fall tissues; and (3) that resinic acid areas in fall tissues test negatively for resene. In the middle of May roots dug about May 1 were tested for percentage of ether extract. Such data are recorded in the ecologi- cal section of this paper. This material shows both resene and resinic acid present in tissues at this particular time of the year, when the leaves had been well developed and metabolic processes were near the zenith point. When tests were made on various parts of the plant to discover whether a Mach test could be secured, the test was negative. These tests were made on stem and root tissue and on cotyledons and embryo within the seed coat. Later certain crystals were noted in the connective and storage tissues of the plant, spheroidal in shape, with rays arising from an eccentric umbo. The crystals were observed in material which had been preserved in alcohol en bloc. These crystals did not occur in fresh aqueous mounts nor in fresh material sectioned and mounted in alcohol. The type of the crystal was such and its reaction to reagents such as to establish 1917] FAUST—RESIN SECRETION 467 it as the crystallized inulin, a colloidal polysaccharide. In ordinary growing tissues these crystals are deposited in a viscous lemon- yellow mass, but in alcohol they undergo certain changes in shape. In readily permeable tissues they are laid down as granular masses, but where there is slow alcoholic penetration they are laid down as sphero-crystals. Such crystals are well illustrated and their loca- tion shown in fig. 36 (si). They are found in connective tissue, especially in the rays and in the inner cortex. In this same speci- men the canals are filled with resin. The semiviscous, semigranular ° resene is well brought out in fig. 16, the section of a very young subsidiary root without secondary thickenings yet developed. In fig. 17, the section of a subsidiary root further developed, is shown in the more permeable outer region of the cortex the semiviscous, semigranular inulin, while the sphero-crystals are found in the inner cortex, not so permeable to alcohol. Other observations on the growing stem buds showed the follow- ing relationships. Young etiolated stem buds showed no inulin, while green stem buds were filled with inulin. Such observations are proof that the result of the photosynthetic process in B. sagit- tata is inulin. Such a substitute for starch is found in the related Compositae, Helianthus annuus, Inula Helenium, and for roots of Dahlia spp. As the microchemical tests progressed, evidence became stronger that a genetic relationship existed progressively in turn between each two of the three products found in Balsamorrhiza, namely, inulin, resene, and resinic acid. The hypothesis built up on this evidence may be stated thus: Inulin> ‘6 &e' | \ \ ~ fast, \ ¥ TION 4 A (SIN SECRE JST on RE FAU 4 PLATE XXXI BOTANICAL GAZETTE, LXIV VOE ite @ iy ada: SG 0 [et] En a HAG LL A Kf cE may) OE Ki at ¥ bs Nene, M4 + : (7 at a Hy . i UU S t 36 | 2 U Ne 3 \ CMZODE OTST FAUST on RESIN SECRETION 1917] FAUST—RESIN SECRETION 479 ments, and sclerified stele; inulin deposits in outer cortex granular; in inner cortex, sphero-crystals; mx, metaxylem; ph, phloem; c, cambium; sch, sclerome; en, endodermis; hy, hypodermis; e¢, epidermis; X150. IG. 18.—Section through old subsidiary root, showing formation of resin canals in region of endodermis: rc, resin canals; 150. 1G. 19.—Detail of sections of stone cells: a, section at edge of cell showing unsclerified pores; b, border of internal opening; c, d, through center of cells; a, 6, d, longitudinal sections; c, transverse sections; 300. IGS. 20—-23.—Sections Sf itcraile critical levels of a 2 mm. seedling: fig. 2 region of hypocotyl; fig. 21, lower cotyledonary collar; fig. 22, upper ae donary collar; fig. 23, iver reaches of cotyledons; w, x, y, 2, primary bundle traces in hy pocetyl: p, r, s, t, secondary bundles of cotyledonary collar; white areas in sacs phloem; black areas, xylem; dotted areas, metaxylem; X60. Fic. 24.—Longitudinal diagram of bundle traces in region of hypocotyl and lower epicotyl, reduced to one plane: k, m,n, 0, primary traces of epicoty]; other designations as in figs. 20-23. Fic. 25.—Transverse section through peduncle: 9, pith; c, cortex; 7, resin sate of outer series; r2, resin canals of inner series; 150. Fics. 26-30.—Cross-sections of resin canals of root at various stages of Pe asa fig. 26, first periclinal division of initial endodermal cell; fig. 27, first oblique division; figs. 28, 29, progressive stages in formation; fig. 30, fully developed canal; Ca, Casparian thickening; 150 IG. 31.—Transverse section of old root (4 or 5 years), showing two series of canals ie radial anastomoses; Xt. Fic. 32.—Longitudinal ictal section of fully aig ty canal; X150. PiG. | 33 et hidon? of young seedling in ese tae deel region, showing radial a moses of two series of his canals in root system rr, Outer series; 72, inner cue: a, radial canals. Fic. 34. Scheneae diagram*from sections, illustrating extent and con- nections of resin canals of 5 mm. seedling, in region of hypocotyl: r:, outer series of canals; r2, inner series of canals; a, radial canals. Fic. 35. 2 Section through origin of resin canals of stem: a, initial canal cell in process of division; }, cells dividing a second time; ¢, d, subsequent divisions to form canals; 300. 1G. 36.—Section of 3-year-old root, stained to mae distribution of inulin and resin: si, sphero-crystals of inulin; r, 7, resin deposits. Fic. 37.—Detailed sketch of inulin, resene, and resinic acid: a-d, wi pith cell of stem; e, f, deposited from evaporation of alcoholic solution; a, crystal of inulin; i; crystals of resene within cell; c, d, resene crystals im ee in resin masses; e, detail of resene crystal; /, resene crystal imbed masses; 150. DISTINGUISHING CHARACTERS OF NORTH AMERICAN SYCAMORE WOODS WARREN D. BRUSH (WITH PLATES XXXII-XXXVIII AND THREE FIGURES) Native sycamores* Four out of the five known species of sycamores (Platanus) are natives of North America. One of these is found in the eastern — United States, one in the southwest, one in the Pacific Coast region, and one in Mexico. The only species in the Old World inhabits central and southern Europe and southwestern Asia. The North American species are the common sycamore (P. occidentalis L.), California sycamore (P. racemosa Nutt.), Arizona sycamore (P. Wrightii S. Wats.), and the Mexican sycamore or alamo (P. Lindeniana Mart. and Gal.). The oriental plane tree (P. orientalis L.) is perhaps the most widely known as well as one of the largest trees in the temperate climate and is frequently planted for shade in streets and parks. Gross structure The only sycamores considered in this paper are the three species native to the United States: the eastern or common, the California, and the Arizona sycamores. The woods of these native sycamores so Closely resemble each other in general appearance that « The name sycamore rightly belongs to a fig tree (Ficus sycomorus L.), a native of Asia Minor. Sycamore is a combination of two Greek words, sykon, a fig, and a mulberry. The leaves of this oriental fig tree resemble those of a mulberry In Acntialls this name is applied also to Panax elegans F. and M. and Sterculia lurida and M. In France the name faux sycomore is given to the China-tree (Melia Azedarach L.). The name is ee applied in this country to sycamore maple (Acer pseudo-platanus L.), because of a general resemblance of the leaves. Plane tree is the generally accepted name ee the oriental Platanus orientalis, and it has been applied to the North American P. occidentalis from early times. The names applied locally, however, are buttonball, buttonwood, cottonwood, and water beech. Button- ball is a suitable name because it has not been applied to any other tree, and it is descriptive of the fruit. Sycamore is the accepted trade name and the one most widely used Botanical Gazette, vol. 64] [480 1917] BRUSH—SYCAMORE WOODS 481 the elements which serve as distinguishing characters must be mag- nified, to some extent at least, for positive identification. The chief distinguishing characters of the sycamore woods are the color of the sapwood and heartwood and the size of the pith rays. The average weight? and hardness of these woods differ very little, and hence they cannot be depended upon as distinguishing characters. Specific gravity and the weight per cu. ft. are shown in table I. TABLE I Species Specific gravity ve taie tock Platanus occidentalis ce oO. 5678 35-39 Platanus Wrightii.......... 0.4736 29.51 Platanus racemosa.......... 0.488 30.41 SAPWOOD AND HEARTWOOD While the sapwood and heartwood usually do not show distinct limits, they are easily distinguishable from one another by their color. The sapwood of the eastern sycamore is light brown, and the heartwood has a decidedly reddish tinge; the sapwood of Cali- fornia and Arizona sycamores is a yellowish white, while the heart- wood is somewhat darker and only slightly tinged with red. In all species the sapwood occupies only a thin zone. Both the color and thickness of the sapwood and heartwood, however, are very variable, depending probably to some extent upon the age, climate, soil conditions, and the general health of the tree. Trees growing in low or moderately wet soil usually develop thicker sapwood than those found on higher well drained ground. As a rule the eastern species has a thicker sapwood than the western ones. ANNUAL RINGS OF GROWTH Annual rings of growth in all three species (pls. XXXII-— XXXIV, ew and Jw) are clearly visible to the unaided eye. Each ring is defined from the next layer by a more or less distinct a Ble ESO ry ? The Hardwood Manufacturers’ Association h sycamore lumber to be 3200 pounds per 1000 board feet. The testi per board foot of the western species has not been listed. 482 BOTANICAL GAZETTE [DECEMBER tangential line made up of several rows of radially flattened wood fibers which mark the outer boundary of the late wood. The early wood of the next annual ring lies immediately outside of this dense tissue, and it begins with a more or less continuous row of pores. The portion of the ring formed in the beginning of the year’s growth is thus considerably more porous than that produced at the end of the season. The pores are slightly less numerous and smaller in diameter in the late wood than in the early wood, but they are so nearly uniform in size throughout the annual rings of growth that with the unaided eye they do not materially assist in defining the inner and outer boundaries of growth rings. The annual rings do not differ in the three sycamores except that in the eastern species they are less clearly defined than in the other two. The width of these annual layers of growth varies considerably. The annual diameter increment of the eastern species for trees of about go years of age and growing under average soil and site conditions is approximately 0.2 in. per year. On an average the western species grow much more slowly. PITH RAYS _ The numerous broad pith rays constitute the most striking character of sycamore wood; they are conspicuous (pl. XXXII, pr ) both in the transverse and radial sections. In the distinctness of its pith rays sycamore woods have a general resemblance to beech, the large pith rays of the latter, however, being less numerous. The rays of sycamore wood are very conspicuous in quarter-sawed boards, giving the cut surface a “silver grain” effect similar to quarter-sawed oak. In tangential or “bastard cut” boards the pith rays are least conspicuous, although clearly visible to the unaided eye. With the hand magnifier they appear as numerous and evenly distributed, short, vertical lines. As stated, the size of the pith rays is one of the chief distinguish- ing characters of the sycamore woods. In gross structure (as seen with the hand lens) the rays are decidedly larger and usually darker in the common sycamore than in the other two species. 1917] BRUSH—SYCAMORE WOODS 483 Minute structure The pith rays are the only reliable means for identifying the woods of the sycamores. As viewed in the tangential section, the pith rays are broadest horizontally in the common sycamore and narrowest in the California species; the rays are lowest vertically in the common sycamore and highest in the California species. The rays of the Arizona sycamore are intermediate in character. These characters can readily be seen under the microscope. VESSELS The wood of the sycamores is diffuse porous, that is, the pores or vessels are of approximately the same size and more or less evenly distributed throughout the annual ring of growth. They are often grouped, and together they constitute about one-half of the trans- verse area between the pith rays. In outline these pores are irregular and may be oval, elliptical, or nearly round; the sides in contact with other vessels are usually much flattened. The vessels first formed in the spring are usually compressed tangen- tially. Average diameters were computed from 50 measurements on each of the 3 species, and show very little variance (table II). TABLE II AVERAGE, MAXIMUM, AND MINIMUM DIAMETER OF VESSEL SEGMENTS OF THE THREE SPECIES Species | Average Maximum Minimum Platanus occidentalis....... 0.083 mm.| o.101mm.| 0.063 mm Platanus Wrightii.......... 0.076 0.094 0.039 Platanus racemosa......... 0.073 0.093 0.062 The vessels are thin-walled and are composed of numer- ous short segments placed end to end. The upper and lower ends of these segments are usually slanting, the oblique end always facing the pith rays. In tangential or radial section these segments are readily measured under the microscope; table III gives averages computed from 25 measurements on each species. AVERAGE, MAXIMUM, BOTANICAL GAZETTE TABLE III THE THREE SPECIES [DECEMBER AND MINIMUM LENGTHS OF VESSEL SEGMENTS OF Species Average Maximum Minimum Platanus occidentalis ....... °.786mm.| o.889mm.}| o.718mm Platanus Wrightii......... ©.549 0.727 °.390 Platanus racemosa ......... 0.677 ©.749 ©. 608 WOOD FIBERS These elements form the ground mass of sycamore wood, and their walls are usually much thicker than those of other wood ele- ments. The fiber length does not differ very much for the three species. They are shortest in Platanus racemosa and longest in P. Wrightii, but the difference is so slight that it cannot be depended upon as a reliable distinguishing character. Table IV gives the average lengths of 100 measurements on each species. TABLE IV AVERAGE, MAXIMUM, AND MINIMUM LENGTHS OF FIBERS OF THE THREE SPECIES é Species Average Maximum Minimum Platanus occidentalis ....... 1.63 mm 2.02 mm. I.39 mm. Platanus Wrightii......... 1.69 2.02 1.47 Pitas FRCEMUEE ios 2... ¥, a5 1.93 1.26 TRACHEIDS The tracheids of sycamore wood (pls. XXXII-XXXIV, /, and fig. 1, E) are found usually adjacent to vessels. These elements, together with the wood parenchyma fibers, form more or less con- tinuous irregular lines throughout the masses of wood fibers, from which they may be distinguished by their thin walls. Tracheids take an intermediate position in respect to size and form between vessels and wood fibers, and in sycamore wood they often possess characters belonging to either one or the other of these two very dissimilar kinds of elements. About midway between these two extreme forms (the vessel and the fiber) is the more or less fixed form, 1917] BRUSH—SYCAMORE WOODS FED \ Min SS \ p) nn eS as VAN \ ee ys Fic. 1.—A, vessel segment of P. occiden- talis with se perforations (~) at both ends, one at lower end with single bar (); 9, bor- dered pits; sp, simple pits; <150; B, end o vessel segment of P. occidentalis, Shows sca- starm (laddsst¢ (ladder 150; C, portion of vessel wall of P. Sgeelaieles enlarged to show bordered pits on upper surface (a) and in profile (6); X400; D, intermediate form between vessel and tracheid from wood of P. occidentalis, showing simple perforation at lower end () and scalariform perforations at upper = (scp); bp, bordered pits; SP, simple pits; 5k — oblique sim; le pits; X150; £, tracheid of P. Wrightii with slitlike perforations se both ends (s/p); sp, 8imple E pits; Xr150. ee \ aS & ane an \ \ ) \ \ \ atk ‘ he oa NNGLY ‘us AVA ‘VARthttD 486 BOTANICAL GAZETTE [DECEMBER the “typical tracheid” or “true tracheid.” This form, which occurs in the wood of practically all of the broadleaf trees, is analogous to the tracheid of the conifers. From the primitive tracheid form there seem to have developed throughout the broadleaf tree species two highly specialized forms, vessel and wood fiber. In the genus Platanus the general term “‘tracheid”’ must be made to include all transitional forms between the typical tracheid and the vessel on the one side, and between the typical tracheid and the wood fiber on the other side. The typical tracheid is moderately thin-walled, has oblique simple pits, and the perforations at the ends are slitlike (fig. 1, £). The tracheid forms between the typical tracheid and the vessel possess, in addition to the oblique simple pits, rows of oblique bordered pits and transverse simple pits, both of which forms occur in the walls of vessels (fig. 1, A and D, bp and sp); and the perfora- tions at the ends may be simple, either with or without bars, or scalariform, as in vessels; or the perforation may be a transitional form between the scalariform as found in vessels and the slitlike perforations found in true tracheids (fig. 1, D, sp). The tracheid forms between the typical tracheid and the wood fiber are some- what slender, pointed at both ends, and thick-walled, and possess the vertical bordered pits of wood fibers in addition to the oblique simple pits belonging to tracheids. They often have also small transverse slits like those in the ends of true tracheids (fig. 2, D, slp). These tracheid forms (or tracheids) of sycamore wood, therefore, although extremely variable, may be defined as moder- ately thin-walled, elongated elements with slightly oblique ellipti- cal or slitlike simple pits and slitlike perforations at the ends. They may also possess those pits common to either vessels or wood fibers, and the perforation at the ends may be simple, scalariform, or slitlike, these types often grading into each other. The average tracheid is 1.3 mm. in length and about 0.04 mm. In diameter. 3 A study of such transitional forms as are found in the wood of the sycamores is of great value to the student in wood structure, in that it shows the relationship of the elements to each other and assists in their classification and in the recognition of the essential features belonging to each class. 1917] BRUSH—SYCAMORE WOODS 487 WOOD PARENCHYMA FIBERS Wood parenchyma fibers, used for the storage of food materials, are usually less than half the length of the wood fibers, are moder- ately thin-walled, and composed of a number of individual cells. In sycamore woods wood parenchyma fibers occur only in the neighborhood of vessels and pith rays, from which they obtain their food supply. Each fiber consists of 1-8 oblong or cubical cells. Two forms of wood parenchyma fibers may be distinguished in sycamore wood. The fibers of the first form communicate directly with the vessels and have large transverse simple pits (fig. 2, A). The fibers of the second form communicate with one another and with those of the first form, but they do not communicate directly with the vessels; these have dotlike bordered pits (fig. 2, B). INTERMEDIATE FIBERS Intermediate fibers, although very similar to wood fibers, also serve for food storage. They are slightly thinner-walled and shorter than the latter and possess many small oval oblique bordered pits. They may be distinguished from the wood fibers, among which they are sparsely scattered, by the starch contained in them. They are intermediate in form and function between wood paren- chyma fibers and wood fibers; hence the term “intermediate fiber.” PITH RAYS The three species of sycamore woods may be distinguished from each other by the pith rays. The rays of common sycamore are much broader in tangential section (pl. XXXV, pr) than those of the other two species. They have an average width of 14 cells, and the ratio of width to height is 1:5. The rays are narrowest in the California sycamore (pl. XXXVII, pr); they average only 5 cells wide, and the ratio of width to height is 1:26. The rays in Arizona sycamore (pl. XXXVI, pr) average 8 cells wide, and the ratio of width to height is 1:12. In all species the pith rays abruptly widen in transverse section at the boundary of each annual ring of growth (pl. XXXIII, pr). The pith ray cells as seen in radial section are usually much longer than they are high, 00 BOTANICAL GAZETTE [DECEMBER — 488 le ° io @ Si 2 S : isk | fem @ E E| — @ Pet ey = 3 = Bia t => fe? = be —> ?e =f ooh ( ° J=ter fal : les ok f e = ee : = Ci ff — % 0 me =) | s =| \ 1 [2] SESES c zs oa a Oe ey, tan Fic. 2.—A, wood parenchyma fiber of P. racemosa with leva simple pits (sp) and 3 small bordered pits (bp); also showing tubelike projec- tions (¢); 250; B, wood parenchyma fiber of P. racemosa with Seotcben pits (6p); also show- es ing tubelike projections (¢) often with pit (9); \ ‘150; C, intermediate fiber of P. occidentalis with oblique oval bordered Lay (bp); X1 as D, intermediate form between fiber, from wood of P. Wrightii, showing slitlike perforations (slp) ctl to those in tracheids, small vertical slitlike bordered pits (bp), and oblique simple pits og (sp’); eu . wood P. racemosa, showing vertical (ome slitlik enlarged to show of e bordered pits (bp); 100; F, end of wood fiber of P. racemosa form of bordered pits (bp); 200; G, forked end of a wood fiber of P. racemosa, X359- 1917] BRUSH—SYCAMORE WOODS 489 except toward the outer boundary of each year’s growth, where they become very much shorter (pl. XXXVIII, pr). The cross- walls between the ray cells are sometimes vertical, but more often they are slightly oblique. Analytical key Pith rays 0.22-0.34 mm. wide (average 0.29 mm. or 14 cells); average height, 1.36 mm. or 50 cells; average ratio of width to height, 5.—P. occidentalis (pls. XXXII, XXXV, XXXVIII). Pith rays 0.10-0.22 mm. wide (average 0.16 mm. or 8 cells); average height, 1.84 mm. or 84 cells; average ratio to height, 12.— P. Wrightii (pls. XX XIII, XXXVI). ce ee a ma LZ oe QS Setrst fer + tS ieee 2 o 2 200 0 09 s¥ Se —=S—— ! 7. , © 7 o © 6 : , oo © Pr erssah o*o 2 o. «9%. 9 A -—* 'er_ ® = t = Fic. 3.—Radial view of portion of pith ray of P. racemosa: a, individual paren- chyma cells; bp, bordered pits; c, crystal; 200. Pith rays 0.04-0.20 mm. wide (average 0.09 mm. or 5 cells); average height, 2.36 mm. or 107 cells; average ratio of width to height, 26.—P. racemosa (pls. XXXIV, XXXVII). Individual characteristics P. occidentalis L., common sycamore (pls. XXXII, XXXV, XXXVIIT) Distribution—Southeastern New Hampshire and southern Maine to northern Vermont and Lake Ontario (Don River, near north shores of the lake); west to eastern Nebraska and Kansas, and south to northern Florida, central Alabama and Mississippi, and Texas (Brazos River and thence south to Devils River). Uses.—Common sycamore is used to a large extent for plug tobacco boxes, furniture, butchers’ blocks, ox yokes, wooden bowls, and cooperage, blind wood in cabinet work, chairs, refrigerators, 490 BOTANICAL GAZETTE [DECEMBER parquetry, sewing machines, picture molding, saddletrees, vehi- cles, and bookcases. It is cut radially for veneer. This is because the “‘silver grain,”’ made by the large pith rays, is very prominent, thus giving the appearance of oak. Gross characters—The wood is moderately hard and heavy, not strong, close-grained, very tough, usually exceedingly cross-grained, difficult to split, and not durable in contact with the soil. It is easier to split when dry, but is liable to warp in seasoning. The heartwood is a reddish brown, especially in older trees, with a decidedly reddish color in the pith rays; the sapwood is light brown, and the transition from sapwood to heartwood is quite gradual. The annual rings of growth (pl. XXXII) are less clearly defined than in the two western species. The pith rays are very conspicuous (pl. XXXII, pr). Vessels (transverse section, pl. XXXII, v)—These occur either singly or else in irregular groups of 2-5. The last arrangement is the usual one in the early wood. At the beginning of each annual ring and immediately adjacent to the several rows of much radially flattened wood fibers which mark the end of the preceding growth layer is an interrupted row of tangentially compressed vessels (pl. XXXII, v) somewhat larger than those formed later. The vessels diminish slightly in diameter and in number toward the outer part of the annual ring, where they are usually isolated. They measure 0.06—o.10 mm., with an average of 0.083 mm. in diameter (table II). Vessel segments (tangential section, pl. XXXV, 2) vary from 0.72 to 0.89 mm. in length, with an average of 0.786 mm. (table III). The vessel walls are much thinner than those of the surrounding cells. Where two segments join endwise, the opening between them is large and elliptical, or often the end walls are not completely absorbed, leaving a scalariform or ladder-like opening, with 1~25 bars like those found in the ends of the tracheids (fig. 1, B). These bars are much narrower than the openings OT slits between them and are often branched. The oblique end of the vessel segment is often prolonged, forming a projection which overlaps the adjoining segment above and below. The vessel walls are marked by vertical and horizontal rows of numerous small, slit- like, bordered pits, which are horizontal, or often slightly oblique. 1917] BRUSH—SYCAMORE WOODS 491 These serve as means of communication between vessels. Large transversely elongated, oval, simple pits connect the vessels with wood parenchyma fibers (fig. 1, A, sp). Tracheids (pl. XXXII, t).—These are numerous and variable in form, and all gradations between vessels and wood fibers may’ be found. True tracheids have numerous slightly oblique, elliptical, or slitlike simple pits (fig. 1, Z, sp) throughout their entire length, and at both ends there are many long slitlike openings where they overlap other tracheids above and below (fig. 1, E, slp). In addi- tion to these pits of the true tracheids most tracheids possess rows of slitlike bordered pits and the transverse oval simple pits found in vessels (fig. 1, Dand A, sp and bp); hence they somewhat closely resemble vessels. Also many of the tracheids have at one or both ends a simple perforation (fig. 1, D, p) either with or without bars, like those in vessels, in place of the slitlike openings found in true tracheids, or else the perforation at the end may be intermediate between the slitlike and scalariform types (fig. 1, D, scp). Tra- cheids are also found which resemble wood fibers, but these are not numerous. They possess, in addition to the oblique simple pits of tracheids, the small vertical or often slightly oblique slitlike bor- dered pits which characterize wood fibers (fig. 2, D and E, dp). These tracheids are usually more or less pointed at both ends and sometimes possess small slitlike perforations similar to those found in true tracheids (fig. 2, D, slp). Wood fibers —These are round, angular, or flattened in trans- verse section (pl. XXXII, wf). They are long, slender, and long- acuminate at the ends, and are marked by numerous small slitlike, obscurely bordered pits* (fig. 2, Eand F, bp). The pits are vertical or oblique, often at an angle of 45°, the oblique position being greatest in fibers with wide lumina. The ends are sharply pointed and often conspicuously forked (fig. 2, G). They vary from 1.39 to 2.02 mm. in length, with an average of 1.63 mm. The broad thin-walled wood fibers, as already described, often show a resem- blance to tracheids. Wood parenchyma fibers-—These have acute ends, are moder- ately thin-walled, and are composed usually of 4~8 individual cells. ‘The border is hardly visible where the fibers have been isolated by maceration. 492 BOTANICAL GAZETTE [DECEMBER Two types of wood parenchyma fibers may be distinguished in the wood of the sycamores, although these may grade somewhat into each other. The elements of one of these types are found adjacent to vessels, which they somewhat resemble and with which they communicate through horizontally elongated elliptical simple pits (fig. 2, A, sp). Small dotlike or circular bordered pits are also sometimes found in these elements which put the wood parenchyma fibers in communication with one another. The cross-walls between individual cells are usually slightly oblique and are pierced by numerous slightly bordered pits. The second type is larger, usually more tapering at the ends, and the individual cells composing it vary considerably in size and form, so that frequently one individual cell is found overlapping two other cells of the same fiber (fig. 2, B). The cross-walls are usually oblique, often approaching the vertical, so that the individual cells are often pointed at the end. This type is characterized by small round or dotlike, slightly bordered’ pits (fig. 2, B, bp), which put them in communication with pith ray cells and other wood parenchyma fibers. The walls in certain places are often locally thickened. Wood parenchyma fibers slightly separated by two contiguous vessels often connect by means of tubular outgrowths from their lateral walls (fig. 2, A and B, #). By means of these tubular pro- jections, which are usually pitted at the points where they join, wood parenchyma fibers communicate with one another. Fre- quently these projections end blindly. Intermediate fibers (fig. 2, C).—These resemble wood parenchyma fibers in the fact that their walls are irregularly thickened and that their ends are somewhat blunted. They more closely resem- ble the wood fibers in form, although broader and much shorter 5 By some investigators a pit is considered bordered only when the pit canal widens out abruptly toward the outside of the cell wall, the outer portion forming an angle with the inner portion of the pit canal which opens into the lumen; where no such widening occurs the pit is simple. On this basis, however, all transitional forms between simple and bordered pits can be found in wood cells; hence the classi-, fication is merely an arbitrary one. It is thought best in the present paper to con- sider pits as bordered where the walls of the pit canals are not parallel and where they give the appearance of a border in longitudinal sections. 1917] BRUSH—SYCAMORE WOODS 493 than the average wood fiber. They have numerous oval oblique bordered pits. Pith rays (pls. XXXII, XXXV, XXXVIII, pr).—These are very conspicuous. They are on the average 14 cells (0.29 mm.) in width and are about 5 times as high. The pith ray cells are ellip- tical in the tangential section and are usually much elongated radially. The side walls are thickened and marked by many dotlike slightly bordered pits which place them in communication with the surrounding elements (fig. 3, bp). Crystals are very abundant in the pith ray cells. : P. Wrighttt S. Wats., Arizona sycamore (pls. XXXII, XXXVI) _ Distribution —Southwestern New Mexico and southern Arizona, Mexico (Sonora). Uses.—The wood of Arizona sycamore is little used. This is on account of its small dimensions and the limited supply of suitable saw logs. It is very similar in its chief structural characters to the wood of California sycamore. While this wood does not occur in the market, it possesses qualities useful for the same purposes as the wood of the common sycamore, and it could be applied to these uses were the tree larger and sufficiently abundant to warrant its exploitation. Gross characters.—The wood is somewhat lighter and softer and also less cross-grained and easier to split than that of the com- mon sycamore. It is weak, very close-grained, and quite tough, but not very durable in contact with the soil. The sapwood is light colored or almost white, and the heartwood is light brown with a reddish tinge. The annual rings (pl. XXXIII) are clearly defined on a smooth transverse section. The pith rays are clearly visible, though not as prominent as those of the com- mon sycamore. Minute characters —Vessels in transverse section (pl. XX XIII, v) are arranged singly or in groups, just as in the common sycamore already described. In the beginning of the early wood the vessels 494 BOTANICAL GAZETTE [DECEMBER form a fairly continuous row, but they gradually diminish in diame- ter and in number as they enter the late wood. They vary from 0.04 to 0.09 mm., with an average of 0.076 mm. in diameter (table II). The veined segments are relatively short in this species, varying from 0.39 to 0.73 mm., with an average of 0.55 mm. in length (table III). Where two vessel segments join end to end the perforation is asinthe commonsycamore. Tracheids (pl. XXXIII, t) are variable in form, some closely resembling vessels and others very similar to wood fibers. Wood fibers (pl. X XXIII, wf) form the bulk of sycamore wood. The length of these elements in Arizona sycamore varies from 1.5 to 2 mm. in length, with an average of 1.7 mm. They are thick-walled and pitted as in the common sycamore. The wood parenchyma fibers and intermediate fibers of Arizona sycamore are similar in all respects to those of the other two species (fig. 2, A, B, C). Pith rays (pls. XXXII, XXXVI, pr) are conspicuous; the average of the large rays is 0.16 mm. wide and about 12 times as high, and therefore much narrower and somewhat higher than in the common sycamore. The pith ray cells are round in the tangential section (pl. XXXVI, pr), and are usually much elongated radially. P. racemosa Nutt., California sycamore (pls. XXXIV, XXXVIT) Distribution.—California (from the lower Sacramento River through interior valleys and coast ranges) to Lower California (San Pedro Martir Mountain). Uses.—California sycamore wood, because of its limited supply, is used only locally and only to a small extent. It is somewhat lighter in weight and in color than the common sycamore, and is also less cross-grained and hence easier to work. Users of this wood claim that it is more durable and is also less liable to warp than the common sycamore. It should be useful for all purposes for which common sycamore is used except where great toughness is required, as in butchers’ blocks, ox yokes, wooden bowls, etc. It should be found useful especially for tobacco boxes, for which the wood of the eastern sycamore is so extensively used. 1917] BRUSH—SYCAMORE WOODS 495 Gross characters.—In general appearance the wood is similar to that of Arizona sycamore, although it is slightly lighter, softer, and more durable. Although moderately tough, somewhat cross- grained, and rather difficult to split and work, it is relatively weak. The heartwood is light brown, slightly tinged with red; the sapwood is light yellowish brown. The annual rings of growth are more or less clearly defined on a smooth transverse section (pl. XXXIV). The pith rays (pl. XXXIV, pr) appear as numerous conspicuous thin lines. Minute characters.—Vessels (pl. XXXIV, v) are quite evenly distributed throughout the annual rings of growth and are grouped as in the other two species already described. The beginning of each annual ring is marked by a well defined row of slightly tan- gentially flattened pores larger than those formed later. They measure 0.06-0.09 mm. in diameter and average 0.073 mm. (table II). The average length of vessel segments is 0.677 mm., varying from 0.61 to 0.75 mm. in length (table III). Tracheids (pl. XXXIV, #) do not differ from those in the other two species described and show the same transitional forms to vessels and wood fibers. Wood fibers (pl. XXXIV, wf) are from 1.26 to 1.93 mm. long, with an average length of 1.55 mm. (table IV). Wood parenchyma fibers and intermediate fibers are in all respects similar to those of the other two species (fig. 2, A,B,C). Pith rays (pls. XXXIV, XXXVII, pr) are conspicuous in all sections. hey are narrowest in this species and have an average width of 5 cells (0.09 mm.). They are on an average 26 times as high as wide, being thus much higher than in the other two species. The pith ray cells in the tangential section are round and slightly higher than broad. Forrest SERVICE Wasuincton, D.C. EXPLANATION OF PLATES XXXTI-XXXVHI PLate XXXII.—Transverse section of wood of common sycamore (P. occidentalis), showing parts of two annual rings of growth; ew, early wood; lw, late wood; 2, vessels; wf, wood fibers; pr, pith rays. 496 BOTANICAL GAZETTE [DECEMBER PLATE XXXIII.—Transverse section of wood of Arizona sycamore (P. Wrightii), showing parts of two annual rings of Dake ew, early wood; lw, late wood; v, vessels; wf, wood fibers; pr, pith ra PLATE XXXIV. —Transverse section of wood - ‘Colifotnia sycamore (P. racemosa), showing parts of two annual rings of growth: ew, early wood; lw, late wood; v, vessels; wf, wood fibers; pr, pith rays. PratE XXXV.—Tangential section of wood of common sycamore (P. occidentalis), showing pith rays (pr) in cross-section and vessels (v) and wood fibers (wf) in longitudinal section. Pirate XXXVI.—Tangential section of wood of Arizona sycamore (P. Wrightii): v, vessels; wf, wood fibers; pr, pith rays. PLaTE XXXVII.—Tangential section of wood of California sycamore (P. racemosa): v, vessels; wf, wood fibers; pr, pith rays. PLaTtE XXXVIII.—Radial section a wood of common sycamote (P. occidentalis): v, vessels; wf, wood fibers; pr, pith rays. BOTANICAL GAZETTE, LXIV PLATE XXXII <@q ij |" A! | Ome ee tlt ait - ie y ; : 7 vie 2 etic © 4 ee a L AS > * + “1 An as eel ee _ ae ete +@ Fo iho nO ag Bios. a SS ae s- BRUSH on SYCAMORE WOODS BOTANICAL GAZETTE, LXIV PLATE XXXIIl1 SS od ee What, Shap ik eer ie — =e ee {Oc at ei _ ores ~ fe J ms te Ego cor wet ame i one. 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Or ee gee Se ET SEE LOT OR eR Pr * ~ ca ‘e**- 2 0 ee sass So are rr + eS ue ses os Oem eg 6% 2% * bla ang OSC RTH *en, ein Ms tet ene +? a” Pe ee ee * OG Fhe Fr a Ke x ee ae a ~~ Pel at Soe *@,@). ae Oot ghee gn 5) roe Sata on “9 (eee * os? ~ ee rh yy 2@,7,° @¢05. o>. Me sae ining ry’ +o or tr ry Coase et hd pt Pat tear be : eel oi 8 6 Oe eae . ee +m. ee ofa, el eee ss - * a: pO Org @Fcn: Cam Oo? . , 7's oe a eZ t ‘ Ath eee * ’ e*y.*,. .* . Se eat FE 7 é. Mt er e** = * oe nn mete tg @ « sean “ . = os ta ** “ = NT Ee sey fne ‘ ene oe" tee nes oe 8? o * vee (Sony. = eo od WOODS AMORE * BRUSH on SYC ATE XXXVIT PL BOTANICAL GAZETTE, LXIV opie “et “nga Semana oe BEES ON Ricateatiencaa BRUSH on SYCAMORE WOODS BOTANICAL GAZETTE, LXIV me BRUSH on SYCAMORE WOODS AGENCY OF FIRE IN PROPAGATION OF LONGLEAF PINES E. F. ANDREWS (WITH FIVE FIGURES) The important part played by forest fires in the life history of the longleaf pine has been recognized by a number of recent writers, and HARPER’ even goes so far as to say “that if it were possible to prevent forest fires absolutely the longleaf pine . . . . would soon become extinct.” The connection between the periodic recurrence of these catastrophes and the success of the pine seed- lings in competing for possession of the soil was pointed out by Mrs. ELLEN Catt Lona, of Tallahassee, more than 25 years ago, but the suggestion appears on the face of it so at variance with universal experience as to give little occasion for surprise that it should have been received with incredulity, or at best with indiffer- ence, by those unacquainted with the adaptive provisions of the species and the conditions prevailing in its habitat. The writer has recently been favored with exceptional oppor- tunities for investigating this subject by means of an experiment carried out by nature herself, in the native home of the longleafs, with all the exactness of detail that could be expected in a well ordered laboratory. Even that refined test of scientific accuracy, a control experiment, was provided by a neighboring group of the same species that was not exposed to fire on the occasion referred to. The scene of this spontaneous demonstration lies on the northern slope of Lavender Mountain, in Floyd County, Georgia, a ridge of the Southern Appalachians which is certainly very near, if not actually itself, the extreme inland and upland limit of the longleaf pines as they occur at present. The crest of the ridge, accord- ing to the United States Geological Survey, attains a maximum height of 1695 ft. above sea level, and extends for 12 miles or more in an approximately east and west direction. It is divided * Economic Botany of Alabama, Part 1, p. 26. 497] [Botanical Gaze tte,vol. 64 498 BOTANICAL GAZETTE [DECEMBER transversely by three deep depressions, or gaps, through which traffic is carried on, and the intervals between the gaps are subdivided by numerous ravines into more or less widely separated spurs and knobs. The southern slopes are covered with the remains of great forests of this valuable timber, interspersed with various hard- wood trees and with shortleaf pines (P. virginiana and P. echinata). Fic. 1.—Young longleaf pines reforesting mountain side after removal of ripe timber They have repeatedly been cut for lumber and burned over by “round fires” started in spring by farmers to provide a free range for their cattle, but the longleafs continue to reproduce them- selves with a pertinacity which, if not too diligently thwarted by the blundering incompetence of county officials and the short- sighted greed of ignorant timber cutters, will in the course of 4 generation or two repopulate the southern mountain slopes with a new forest growth sprung from the old stock (fig. 1). 1917] ANDREWS—LONGLEAF PINES 499 While there are traditions of the former presence of this species on the northern side of the mountain, the only traces of them that _ I have been able to find there consist of two small, isolated groups which furnished the apparatus for nature’s instructive experiment alluded to. They are situated on opposite sides of a deep ravine which starts near the top of the mountain, at Fouché Gap (the westernmost of the three passes), and descends in a gradually widening rift to the bottom. The larger and more important of these groups occupies a portion of a steep incline between the crest of the ridge and a now abandoned road that winds along the eastern edge of the ravine. It numbered only five individuals, so far as could be seen when I first took note of them, in the summer of 1913. Of these, the rugged patriarch shown in the center of fig. 2, together with two smaller specimens in the background, one of them a mere sapling, were the only members of the colony conspicuous enough to attract the attention of any but a particularly interested observer. The other two were seedlings not over 4-5 dm. in height, and at this stage of development, when the needles are the only part above ground, so like the coarse grasses around them that even an expert, unless keenly on the lookout, would be liable to pass them by unnoticed (fig. 3). This group of five individuals was scattered over an area of half an acre, more or less, on the edge of an open copsewood which has repeatedly been cut for timber and cleared of undergrowth by minor forest fires. The rest of the declivity, from the gap to the crest of the ridge, had been cleared several years before for cotton planting, but after a short trial was abandoned as too rugged for cultivation. It was at this time (July 1913) neck deep in weeds, mixed with a scrub growth of brush and brambles; and not being in quest of the zoological specimens likely to abound in such places, I did not explore this jungle until two years later, after one of the periodical spring fires had cleared the ground. The second group, which served as the ‘control,’ is situated on the farther side of a low spur or knoll, separated from the neighboring colony by the intervening ravine and the wooded crown of the knoll. It included, when first observed, four indi- viduals, three of which were adults of full cone-bearing age, the 590 BOTANICAL GAZETTE [DECEMBER largest one measuring 2 m. in girth. The offspring of these was limited to one solitary seedling, a disproportion the significance of which will be apparent later, when compared with the progeny of the ‘“‘patriarch”’ on the other side of the gorge. The soil in both situations is the same, a hard, dry, rocky clay, with a characteristic Fic. 2.—In foreground, small portion of old clearing as it appeared after fire, with ‘‘patriarch” on border between it and copsewood; tall Pinus echinata diml outlined at extreme left stands near brow of opposite slope of ravine; beyond is knoll on farther side of which “control” group is situated. ground cover of Pteris aquilina, Tephrosia virginica, and a number of coarse grasses that have a strikingly familiar aspect to one acquainted with the vegetation of the great pine region of the South Atlantic coastal plain. The typical wire grass (Aristida stricta) of 1917 Al tWS—LO] We: NE 501 ] NDREWS—LONGLEAF PINES the southern forests is here replaced bya correspondingly arid growth of “old field broom” (principally Andropogon furcatus, A. virginicus, and A. scoparius), with a few sedges (Scleria triglomerata, Cyperus retrofractus, etc.) intermixed. In fact, the only difference in the environment of the two groups is the isolated position of the knoll, Fic. 3.—Large clump of spearlike leaves near upper lefthand corner is longleaf seedling; others are grasses that have sprung up since fire; skeleton plant on right and white patches in background are hardwood seedlings and bushes killed by fire that left pine seedling unharmed. the top of which is protected by an encircling turnpike road and by the wooded slopes of two deep ravines, watered by mountain springs and clothed with a heavy growth of broad-leaved trees, conditions which oppose an effective barrier against the spread of fire. 502 BOTANICAL GAZETTE [DECEMBER It was not until April 1915 that I made another visit to these straggling longleaf outposts, which had interested me at first merely as landmarks of what seemed to be the ultima Thule of their advance in this direction. But a great surprise awaited me. The region around the gap had recently been burned over, and amid the wreckage of skeleton limbs and blackened stubs to which the weedy jungle in the old clearing was now reduced, there appeared a thriving colony of 33 young longleafs, ranging from a few deci- meters to a meter or more in height. This new growth was con- fined mainly to the old clearing, although the “‘patriarch,”’ whose progeny it presumably is, stands squarely on the border line between the old cotton field and the copsewood, and had no doubt dis- tributed his favors impartially to both. But the absence of trees in the clearing would naturally facilitate the scattering of seeds in that direction, and during the first year or two, before the weeds and brush began to crowd them out, they would germinate freely in the open ground. I had simply overlooked them on my former visit, for the reason that they were hidden in the jungle, where, after making a successful start in life during the palmy days before their little Belgium was overrun by the horde of weedy invaders, they were at last overpowered by numbers and buried out of sight. Deprived of the sunshine so necessary to this sun-loving race, all save the oldest and strongest among them must have perished but for the timely intervention of their powerful ally, the fire, which swept away all rivals and left the young longleafs in undisputed possession of the soil. That such was the case, we have their own direct testimony, for every one of them bore unmistakable marks of fire. Some were so scorched and blackened that any one un- acquainted with the habit of the species would unhesitatingly have pronounced them dead. An examination, however, of a number of the worst injured plants showed that in not a single instance had the growing point been killed, or even seriously damaged. On the other side of the ravine conditions were unchanged except that a new road had been cut around the knoll since my former visit, almost completely encircling it, and one of the adult pines that stood in their way had been felled by the road builders. 1917] ANDREWS—LONGLEAF PINES 503 The fire had not spread in this direction, and I had some difficulty in finding again, among the coarse grasses which these nurslings so closely resemble, the solitary seedling upon which the future hopes of the colony depend. A careful search among the under- growth failed to bring to light any further additions to this decadent family, and, as matters now stand, it looks as though the last remnants of the longleaf forest that once clothed the knoll were doomed to early extinction.’ It would, of course, be rash to attribute this result solely to the absence of fires. Various other factors may intervene, among which must be reckoned the infrequency of seeding that char- acterizes this species, a full crop being produced only at intervals of four or five years. If a forest fire should occur during one of these “lean’’ periods, it would have comparatively little effect, since there would be few seedlings to take advantage of the oppor- tunity offered, while one closely preceding a season of abundance would prepare the way for a proportionate increase in the longleaf population. Another fact to be considered is that the early growth of the longleaf seedling is very slow. The main energy of the plant during the first year or two is expended in developing the long taproot which enables it to cope successfully with the poverty of its habitat by making the most of the meager resources of the soil, and later provides a safe anchorage for the towering shaft of the adult tree. The young specimen shown in fig. 4, and scarcely distinguish- able as yet from a clump of grass, is not less than two years old, and may be more. But while giving due weight to these considerations, I think that after we have studied the effects of fire a little more closely in those cases where its agency is too obvious to be doubted, we cannot deny that it is, and has been in the past, an important factor in the propagation and distribution of the longleaf pines. In July and August of the same year (1915) I made a longer stay on the mountain, during which time I was able to continue my observations on the pines to better advantage. In the lower ?Later observations (September 1917) show a flourishing group of 66 saplings and seedlings in the first colony; while the lower one on the knoll has been reduced to 2 individuals by the loss of the seedling and one of the adult trees. 504 BOTANICAL GAZETTE [DECEMBER group, on the knoll, there was little of interest to record, every- thing remaining very much as when I last saw it. On the upper slope, however, matters were very different, and a more exact count brought the census of the new generation up to 40. Of this number, all of those within the old clearing must have germinated during the 7 or 8 years since the cultivation of this part of the land Fic. 4.—Thrifty longleaf seedling that has established itself successfully on stratum of almost solid rock, made possible by long taproot reaching far down into subsoil. was abandoned, for they would assuredly have been weeded out had any of them dared to show their heads above ground where “cotton was king.” To estimate the ages of different individuals with accuracy, however, is not easy, on account of the great irregularity in the rate of growth. While very slow during the first 2 or 3 years, as already pointed out, it becomes proportionately rapid after the critical period of “infant mortality” is past. The growth for the year 1915, up to the first of August, on two saplings of 2.75 and 2 m. in height respectively, was found by measurement 1917] ANDREWS—LONGLEAF PINES 505 to be approximately 8 and 7.5 dm., while seedlings 12-18 cm. high showed a gain of only 2-4 cm. for the same period. These figures show that the young longleaf, after attaining adolescence, is fully capable of holding its own in the competitive strife of the plant world. The chief danger to the species in this un- ceasing contest is in the risk that the seedling, during its long period of infancy, may be starved and crowded to death by the rapidly advancing host of weeds and bushes that outstrip it in the battle for food and sunlight. Their only safeguard against these enemies is, as we have seen, the forest fire. _ This naturally brings up the question, how does it happen that the young pines themselves are not killed by the heat which destroys their hardier competitors? The answer is before our eyes. The great rosettes of bristling needles, which give to the longleaf pine its venerable aspect, are not the mere decorative emblems of ancient descent that they seem. They are fulfilling the important function of a defensive armor against the most destructive enemy (after man) that the plant population of the world is exposed to. The young of most species quickly succumb at the first onset of even an ordinary ground fire; but the longleaf pine seedling has its growing point closely enveloped in a crown of spearlike needles, as shown in fig. 4, before the stem begins to rise above the ground. These may be anywhere from 20 to 40 cm. long, including the sheaths, which average about 3-4 cm. When fresh they ignite so slowly as to be practically incombustible. Strictly speaking, they can hardly be said to ignite at all, but are bitten off and consumed where the fire comes in contact with them. Moreover, the application of heat causes a violent sizzling and contortion of the parts affected, accompanied by a series of small explosions which are sometimes capable of extinguishing a match; and I have even known them, on one occasion, to put out the flame of a candle. At another time, I was trying to ignite a fresh “pinetop”’ (as these tufts are called in our Georgia vernacular) by the flame of a kerosene lamp, when it fumed and sputtered and caused such a commotion in the burning wick that I cut short the experiment for fear of exploding the lamp and transferred my operations to the kitchen. There was a slow wood fire in the 506 BOTANICAL GAZETTE. [DECEMBER stove, into which I thrust the pinetop, and awaited results, watch in hand. When I removed the stub at the end of 4 minutes, the needles had all been consumed, but the sheaths, especially those of the vigorous young fascicles crowded around the growing point, remained for the most part intact. The bud itself, though consid- erably scorched and blackened externally, appeared, like the stem, not to have suffered beyond the possibility of recovery, though this point, as the final result will show, was open to doubt. | It may be explained here that in excursions through the moun- tains it is desirable to avoid all unnecessary encumbrances in the way of luggage, and, as the conditions of life are very primitive in the regions of greatest interest to the botanist, one often has to resort to homely makeshifts when supplementing observation by ex- periment. It is surprising, however, what interesting results may sometimes be obtained by very simple means when one is deter- mined to get to the bottom of a thing. To complete the experiment, I next placed a couple of fresh pinetops in an upright position over a brisk blaze of chips and twigs out of doors, so as to approximate, as closely as possible, the normal conditions of an ordinary brush fire. After 8.5 minutes, when the flame had subsided and the needles were all burned away, down to their sheathed bases, I placed the stubs in water, together with the one that had been subjected to the ordeal of the kitchen stove on the day before. At the end of 12 days, when my stay on the mountain came to an end, the latter was found to have sustained internal injuries which left it in all probability beyond recovery. The other two came out of the fiery ordeal, if not altogether un- scathed, yet with an appearance of vitality sufficiently unimpaired to warrant the presumption that had they remained attached to the living stem, like their kindred in nature’s outdoor experiment, they would, like them, quickly recover from the effects of the fire. The effectiveness of this provision for the safety of posterity is further assured by the tendency of the needles to persist on the stem of the young shoot for several years, until the more delicate parts are lifted beyond the reach of danger. As the growth of the sapling progresses, and the increasing thickness of the bark provides for the protection of the stem, the needles become massed 1917] ANDREWS—LONGLEAF PINES 507 around the growing axes at the end of the branches, where they form the tassel-like clusters or ‘‘pinetops”’ which are such a striking characteristic of the longleaf pines (fig. 5). Under the influence of light the lateral stems supporting these tassels tend to curve upward. This upright position has the advantage that the fire, which Fic. 5.—Young longleaf pine with stem surrounded by bristlin g chevaux-de-frise of needles, growth of several successive years. ordinarily makes its attack from below, has to cut its way through the entire phalanx of protecting needles before it can reach the growing point. If the rosettes were drooping as in the winter condition of the white pine, they would, instead of protecting the buds, act as refractors to converge the heat upon them. 508 BOTANICAL GAZETTE [DECEMBER With such efficient fire protection it can easily be seen why the longleaf seedling is able to withstand a degree of heat that would be fatal to older and in other respects hardier plants. The same facts also explain why, in a state of nature, these trees tend either to congregate in pure forests over large areas or to become extinct if exposed to unrestricted competition with hardwoods. In the latter case the older conifers may hold their own for a time, but as these die out from superannuation or other causes, the new generation that should replace them, unable to develop in the shade, and cut off from the sunlight by the broad leaves of the hardwoods, fails to reach maturity and the race in time becomes extinct. On the other hand, when forest fires, especially of the minor type known as ‘“‘ground fires” and “brush fires,’’ occur at not too frequent intervals, the immunity of the pines enables them to take the lead in the work of reforestation, and through the gradual elimination of their rivals to become finally the sole possessors of the soil. Rome, Ga. PERMEABILITY OF THE CELL WALLS OF ALLIUM 5: C. BReoors Many investigators have reported that the tissues of higher plants are almost if not quite impermeable to inorganic salts. They have usually attributed this phenomenon to the imperme- ability of the protoplasm to the salts used. It is quite probable, however, that the cell walls themselves may exert an important influence on the permeability of tissues.. It is of interest, therefore, to point out a striking example of the impermeability of the cell wall, which was found when it was attempted to investigate, by the diffusion method recently described by the writer,’ the perme- ability of epidermis from the inner surface of bulb scales of the onion. The principle of the experiment and the apparatus used were the same as in the writer’s experiments on Laminaria, as recorded in the paper cited. .Certain modifications were necessary, however. In order to avoid injury due to drying out of the epidermis (which consists of a single layer of cells), it was necessary to reduce as much as possible the time intervening between the act of stripping the epidermis from the scale and that of filling the cells with solu- tions. The whole operation usually occupied about 30 seconds, a time which caused no observable injury to the cells. Dead material was prepared by exposing freshly sa ee sheets of tissue to chloroform vapor for a period of one hour, then immediately immersing them in a large volume of distilled water, which was several times renewed. After 15 days in distilled water the dead tissue was used in the usual manner. The salt solutions used in the lower cells were always 0.05 M, a concentration hypotonic to the living cells of the onion epidermis. In the upper cells there was placed distilled water having a specific conductivity of about 2xX10~° mhos. Extreme precautions were ‘used to prevent access of dust, acid vapors, or any other soluble material to the distilled water in the upper cells. In all the * Brooks, S. C., A new method of studying permeability. Bor. Gaz. 64: 306-317. Sigs. 2. 1917. 599] [Botanical Gazette, vol. 64 510 BOTANICAL GAZETTE [DECEMBER experiments on this tissue the distilled water was obtained by dis- tillation from an apparatus made entirely of glass, and which had been in constant operation for several weeks prior to the collection of the sample here used.?_ All the kations were used in the form of chlorides, thus making it possible to determine their concentration in the upper cell by two entirely independent methods. The con- ductance of known concentrations from 10~7 M to 1073 M of the salts used was determined and a curve plotted showing for each salt the concentrations corresponding to any given conductance. The concentration of a given salt diffusing into the distilled water in the upper cell was then ascertained by comparison of the con- ductance of the solution in the upper cell with the curve for the corresponding salt. In addition, the chlorides in the upper cell were determined nephelometrically by the method of RICHARDS and WELLs.3 In neither living nor dead tissues could the presence of chlorides in the upper cell in excess of 3X10~5M be detected nephelo- metrically, even during experiments whose duration exceeded 24 hours. The changes in conductivity were also such as would indi- cate a negligible increase in the concentration. It seems therefore that little or no salt can pass through the epidermis. Experiments were then tried to determine the permeability of the tissue to dyes. The diffusion of Bordeaux red through the diaphragm from an o.1 per cent aqueous solution in the lower cell into distilled water in the upper during 96 hours was insufficient to cause any visible change in the color of the distilled water. A similar experiment, in which the lower cell contained a 1 per cent aqueous solution of eosin (Merck’s eosin bluish), was continued for 7 days; at the end of that time the distilled water in the uppet cell could not be distinguished in color from fresh distilled water, even by the use of a colorimeter. The experiments on dyes (as well as those on acids and alkalies, subsequently described) were performed on dead tissue. ? Water distilled from glass becomes better the longer distillation is continued, - since the constant exposure to steam and hot water soon removes the more soluble constituents of the glass. Water such as that here used may be regarded as having no appreciable toxicity. 3 Ricuarps, T. W., and Wexts, R. C., The nephelometer, an instrument for detecting and measuring opalescent precipitates. Amer. Chem. Jour. 31:235- 194 1917] BROOKS—PERMEABILITY 511 In the use of indicators we possess an extremely sensitive and reliable means of demonstrating the presence of small amounts of free acid or alkali in a solution. It would be possible therefore to detect the diffusion through the diaphragm of tissue of small amounts of hydrochloric acid or sodium hydroxide by adding a small amount of a suitable indicator to the distilled water in the upper cell of the apparatus. In the lower cells 0.1 M solutions of the acid and alkali were used. A period of 43 hours was insufficient to allow the passage of an amount of sodium hydroxide great enough to cause any change in the color of the distilled water containing about 0.01 per cent of phenolphthalein, as determined by comparison in a colorimeter with fresh distilled water. The change of hydroxyl-ion concentra- tion necessary to cause the first visible change in the color of the phenolphthalein would be that from 1 X107~° M to 1X1075 M. The turning point of Congo red lies at a hydrogen-ion concen- tration of 1X10~* M. An increase of less than 1X10~*M in the © hydrogen-ion concentration of distilled water containing Congo red will then cause the appearance of the blue coloration in the indicator. Experiments were conducted in which the lower cells were filled with o.1 M hydrochloric acid, and the upper cells with distilled water containing barely sufficient Congo red to cause a distinct red coloration; these showed that a period of 3-5 hours was sufficient to cause the color change in the indicator. Control experiments in which the lower cell was filled with pure distilled water showed no color change in the upper cells during 19 hours. In order to eliminate the possibility that the permeability to hydrogen ions was the result of the action of the 0.1 M hydro- chloric acid on the tissue, several of the cells in which there had been a diffusion of acid were simply rinsed out thoroughly, and the lower cell finally filled (after preliminary rinsing with the solution) with o.1 M sodium hydroxide. The upper cell was filled with distilled water containing a slight amount of phenolphthalein. There was no color change in the distilled water up to the end of the experiment, a period of 3 days. The inner epidermis of onion bulb scales, at least when its cells are dead, is therefore but slightly permeable to hydrochloric acid, and not perceptibly so to any other of the substances tried. These 512 BOTANICAL GAZETTE [DECEMBER included sodium, calcium, and aluminium chlorides, Bordeaux red, eosin, and sodium hydroxide. This extraordinary impermeability is confined to the exterior cell walls of the epidermis, as will be seen by the following simple | experiment. A sheet of epidermis stripped from the scale and mounted in water on an ordinary microscope slide, then irrigated with a o.4 M sodium chloride solution, was strongly plasmolyzed within 30 seconds. In order that plasmolysis should occur, it was necessary that the plasmolyzing solute should pass into the space between the cell wall and the retracted protoplast. Some part of the cell wall is therefore freely permeable to sodium chloride. Pieces of the scale, about 2 cm. square, with the epidermis still in place, were then placed in a 0.4 M sodium chloride solution. At intervals up to 30 minutes pieces were withdrawn, the surface dried with filter paper, and a small piece of epidermis from near the center of the piece of scale removed. These were placed between a microscope slide and cover slip, no water being added, and in all cases their cells were found to be wholly normal in appear- ance; but a few seconds’ irrigation with an o.4 M. sodium chloride solution now sufficed to cause violent plasmolysis. These experi- ments show that the exterior walls of the epidermal cells form a continuous layer highly impermeable to most substances and com- parable to certain seed coats as described by previous investigators.’ Summary 1. The exterior cell wall of the epidermis from the inner surface of onion bulb scales is slightly permeable to hydrochloric acid, while it is practically impermeable to various salts, dyes, and to sodium hydroxide. 2. It is necessary to consider the influence of impermeable cell walls in interpreting experiments on the permeability of plant tissues. LABORATORY OF PLANT PHYSIOLOGY HARVARD UNIVERSITY ‘Cf. Brown, A., The selective permeability of the coverings of the seeds of Hordeum vulgare. Proc. Roy. Soc. London, B 81:82. 1909; SCHROEDER, H., die selektive permeable Hiille des Weizenkornes. Flora 102:186. rgtt; SHULL, C. A., Semipermeability of seed coats. Bot. GAz. 56:169-199. 1913. BRIEFER ARTICLES PYRENOTHRIX NIGRA, GEN. ET SP. NOV. ’ (WITH FOUR FIGURES) The material upon which the new genus and species of lichens here described is based was collected by Professor RoLAND THAXTER, of Harvard University, in Florida in 1897. I wish to acknowledge my indebtedness to Professor THAxTER for his kindness in placing the material at my disposal for study and description. On account of the distinctive combination of a byssine thallus and a teases ode fruit this new genus may appropriately be named as follows Pyrenothrix, gen. nov.—Thallus crustaceo-byssinus ecorticatus sub- strato arcte adnatus gelatinosus, ex hyphis tenuibus leptodermaticis crebre septatis ramosis, filamenta gonidiorum dense obducentibus. Gonidia ad species Scytonemae pertinentia filamentis implexis. Peri- thecia tenues coriacea pseudoparenchymatica, integra simplices recta nuda nigrescentia, in gonidiis sessilia nunquam immersa, ostiolis parum distinctis. Paraphyses persistentes simplices filiformes. Asci clavati. Sporae ee murali-divisae cellulis subcubicis. Sper- magonia non visa. This new genus, by reason of having gonidia of the Scytonema type and fruit of the perithecial form (figs. 1, 2), would appear to belong most naturally to the family Pyrenidiaceae, as coumtituted by ZAHLBRUCKNER (ENGLER and PRANTL, Die Natiirlichen Pflanzenfamilien, Teil I, Abt. 1, p. 76), but differs from all of the genera of that family hitherto described in the byssine character of the thallus (fig. 1), and in the muriform spores (fig. 4). When examined under the microscope, the structure of the thallus and the relation of hyphae — ~ebacgag oy sonia ig nee vegisiee that of Coenogonium (fig. 2). Without question, ““What isa lichen ?”’ it may be said that if Racca | is a lichen ety P imei is a lichen, as the two are strictly analogous. That the perithecia are not those of a secondary parasite or merely accidentally associated with the filaments of the alga is proved by the observa- tion of early stages in their development showing their origin from the web of hyphae that envelop the gonidia (fig. 3). Pyrenothrix nigra, sp. nov.—Thallus fusco-nigricans byssinus sub- strato arcte adnatus late effusus non limitatus, sicco nec flaccido nec 513] [Botanical Gazette, vol. 64 514 BOTANICAL GAZETTE [DECEMBER spongioso, madefacto molle gelatinoso, ex hyphis tenuibus (3-4 » crassis) septatis torulosis crebre ramosis, filamenta gonidiorum crebre obducen- tibus; gonidiis Scytonematicis filamentis, crassitudine 13-18 », vaginis tenuis homogeneis non lamellosis, flexuosis implexis, rarius pseudora- mosis. Perithecia minuta, altit. 200-225 w, crassit. 160-175 #, pyri- formes collo crasso breveque, primum fuliginea demum nigrescentia, ostiolo minute parum distincto. Paraphyses persistentes simplices fili- formes sat flexuosae. Asci clavatae, 8-spori. Sporae fumoso-nigricantes, 3 4 Fics. et i whe ‘: hue akerch, X4y; Fig. 2, end of gonidial filament, showing an ( falce hranc part omitted for clearness), X385; fig- 3, early stage in formation of perithecium, 385; fig. 4, spores, X 385. oblongae vel late seh ae oe ba cpanees 5-6 loculares, 2 locellati, 17-20 6-9 Thallus sicealak HEE. spreading over the substratum without definite limits and closely adnate, byssine, when wet soft and gelatinous, when dry harsh and not at all spongy; made up of gonidia of the Scy- tonema type, with flexuose, intertangled filaments, 13-18 » thick, with a thin, homogeneous sheath and infrequent false branches; the filaments densely covered with septate, torulose, branched hyphae, 3-4 » in thick- ness. Perithecia minute, 200-225 » high and 160-175 thick, pyri- form with a short, thick neck, and minute, indistinct ostiole; the wall 1917] BRIEFER ARTICLES 515 thin, coriaceous, pseudoparenchymatous, at first fuliginous-brown, then blackening. Paraphyses persistent, simple, filiform. Asci clavate, 8-spored. Spores smoky-black, oblong or broadly fusiform, muriform, 5-6 locular, with some of the cells once divided, 17—20X 6-9 p. Abundant on the bark of scrub oaks at West Palm Beach, Florida, Decem- ber 1897 (type!); and on living Oleander at Cocoanut Grove, Florida, No- vember 1897; collected by Professor ROLAND THAXTER. Type specimen in the Cryptogamic Herbarium of Harvard University.—LincoLn W. RIDDLE, Wellesley College, Wellesley, Mass. CURRENT LITERATURE MINOR NOTICES North American flora.—The third part of Vol. 10 continues the presentation of the Agaricaceae by MurRILL,! the 12 genera of Pholiotanae being presented, , excepting the ae Inocybe. The 11 genera presented include 324 species, of which 76 are described as new. The largest genera are Gymnopilus (85 spp.), Naucoria (65 spp.), Hebeloma (50 spp.), Crepidotus (46 spp.), and Galerula (33 spp.). The remaining 45 species are distributed among 6 genera. New species are described in Crepidotus (7), Tubaria (4), Galerula (8), Naucoria (21), Pluteolus (4), Mycena (2), Gymnopilus (13), and Hebeloma (17).—J. M NOTES FOR STUDENTS Carbon assimilation JORGENSEN and SriLes? have summarized our knowledge of the processes involved in the assimilation of carbon by green plants and the pigments concetned in them. The portion dealing w:th the pigments themselves has been reviewed by Linx.3 In the introduction the reviewers express the hope that “the following pages will be of interest to those concerned in the development of scientific agriculture as well as to those inter- ested in plant physiology for its own sake.” The discussion of the path of gaseous exchange between the leaf and the surrounding atmosphere is based mainly on the work of BLACKMAN and Brown and EscomsBe. The conclusion reached is that the proof is now definite that the stomata are the main pat of the intake of carbon dioxide into the assimilating aerial leaf of the higher plants. Any intake that may occur through the cuticle is of very minor impor- tance. Carbon assimilation is regarded as a complex of processes which prob- ably obey quite different laws. Attention is called to the 5 obvious factors upon which the rate of carbon assimilation in the leaf may depend: (1) carbon dioxide supply, (2) intensity of illumination, (3) temperature, (4) water supply, (5) quantity of chlorophyll. To these is added BLaAcKMAN’s time factor. It is found that below 25°C. the rate of carbon assimilation a little more than doubles for each rise of 10° C. For cherry laurel this gives a van’t Hoff curve RILL, W. A., North American flora ro:part 3. pp. 145-226. Agaricales: Agaricaceae (pars), Agariceae (pars). New York Botanical Garden. 1917. 2 JoRGENSEN, I., and Srites, W., Carbon assimilation. A review of recent work on the pigments of the green leaf and the processes connected with them. New Phytol. reprint no. 10. London. Wesley & Son. 1917. ' 3 Bor. Gaz. 62:417-421. 1916. 516 1917] CURRENT LITERATURE 517 in which the temperature coefficient for a rise of 10° C. is 2.1. In Helianthus tuberosus it was 2.5. Below 25° C. the initial rate is maintained, but above that temperature it falls off regularly. The higher the temperature the more rapid is the falling off. The falling off at any given temperature is most she at first and subsequently becomes less rapid. Since it is thus impossible to measure the highest possible assimilation at high temperatures, BLACKMAN estimates it by plotting his experimental results below 25° C. (a van’t Hoff curve in which Qyo= 2.1) and continuing the curve by assuming that the same rule is followed above that temperature. That this curve represents the initial rate above 25° C. is confirmed in BLACKMAN’S opinion by plotting on this same diagram (the abscissae now having a time significance instead of a temperature significance) the values obtained for the assimilation rate at higher temperatures, and continuing these curves back toa point representing zero time. It is thus found that the position representing zero time for each curve is also that representing the temperature at which the readings were taken. n this basis BLACKMAN concludes that there seems to be reason for the preliminary acceptance of the theory that the initial values of assimilation above 25° C. follow the van’t Hoff curve as they do below that temperature. JORGENSEN and STILEs seem disposed to defend BLACKMAN against all criticisms on this point. It must be remembered, however, that CoHEN-STUART has shown that, according to the van’t Hoff law itself, values of Q,. are not constants and that the velocity is not an exponential function of the temperature. Kutypers found that such a method as BLACKMAN used on carbon assimilation did not apply to respiration. Lrrrscu® has also found that it does not apply to temperature and rate of growth. In regard to the light factor, the conclusion is reached that “‘ where temper- ature and carbon dioxide supply are in excess the rate of assimilation is in direct proportion to the intensity of illumination.” In the case of cherry laurel during the middle of an August day (temperature 29°5 C.) the maximum assimilation was possible with 36 per cent of full sunlight, while in the case of Helianthus 69 per cent was necessary Assimilation is shown to increase directly with carbon dioxide supply until some other factor becomes the limiting one. When this point is reached, assimilation remains constant with further increases in carbon dioxide up to ©.0536 per cent. Above this point the rate of assimilation falls off rapidly. BLACKMAN’s interpretation is that this is due to the sasieds effect of the strong CO, on the protoplasm. The reviewers state that ACKMAN Care- fully avoids premature conclusions and tries to find Se euia expressions which will embody all his experimental results.’ 4 Konn. Akad. Wetans. Amsterdam. Proc. Sec. Sci. 14:1159-1172. 1912. 5 Rev. Bor. GAZ. 50:233~234. I9g10. 6 Ann. Botany 30: 25-46. 518 BOTANICAL GAZETTE [DECEMBER In discussing WILLSTATTER’S work on the relation between chlorophyll content and assimilation rate, the reviewers state that “‘ WILLSTATTER advances a simple definite $e dienes and tama 0 obtain spcteaesrnat sae —— will support his theory arbo ti sists of two definite paeceen, one photochemical, taking place in the dito: roplast, and one enzymatic, taking place at the boundary between the chloroplast and the plasma. nee cnyeen is supposedly ee during the latter process. te. The view is not a surprising one, however, since the relation of carbon assimilation and of enzymatic action to temperature both seem to be special cases of TamMaAn’s principle. The surprising thing would be that there should be only two processes concerned. The reviewers state that under certain circum- stances, when no other factor is limiting, the amount of chlorophyll determines the intake of CO. by the leaf. WutisTATTER found th the amount of pigment is not altered during the process of carbon assimilatio he discussion of the present status of our ister of the known products of assimilation (oxygen and carbohydrates) is based on the work done within the last 31 years, since the earlier workers did not separate the gaseous ex- changes due to assimilation from those due to respiration. It seems probable that the real assimilation coefficient (taking respiration into account) approxi- mates unity. In considering the nature of a reaction or a series of reactions, it is very important to know the quantitative relation between initial substances and the final products of the reaction. In carbon assimilation by green leaves the relation between CO, taken in and O, evolved has not been definitely established The reviewers summarize in a table (p. 106) the evidence in regard to the presence of various carbohydrates in the leaf. (1) Polysaccharides (exclusive of cellulose and pectic substances); the presence of starch has of course long been well known, and the presence of pentosans and dextrin seems to be established. (2) Disaccharides; sucrose is certain, and maltose is doubtful. (3) Hexoses; the presence of d-glucose and d-fructose is well recognized. (4) Pentoses; none are positively known to be present, although there is some evidence pointing to the presence of l-arabinose and J-xylose. Definite evi- dence as to what sugars are absent and more quantitative data in regard to the ones present are much to be desired. The reviewers state that there is strong evidence that sugars are the first definitely known products of the assimilatory process, starch probably being a secondary product. Although most workers regard cane sugar as first, there is no satisfactory evidence that the hexoses may not be first. The mechanism of translocation is complex, depending upon differences of enzyme concentration, and possibly upon permeability changes, the nature and causes of which are at present largely unknown. The available data on energy relations are dealt with under three heads: (1) quantitative determinations of materials produced and their heats of combustion, (2) meas- urement of both radiant energy and heats of combustion, (3) assimilation 1917] CURRENT LITERATURE 519 power of light of different wave lengths. Under (1) two methods of estimating the products of carbon are discussed: (a) increase in dry weight, and () amount of CO. taken in. The reviewers conclude that if the dry weight method can be made more accurate, it should not be lightly abandoned. If we assume with BRowNn and Escomse that the heat of combustion of all products of assimilation, is the same as that of glucose (3.76103 gram calories), we shall fall into a considerable error, as is indicated by the following values for other substances present in leaves: sucrose 3.99103, starch 4.110%, cellulose 4.210%. If oils are present, the error in this assumption would be still greater. Actual determinations of heat of combustion made by other workers on the products of assimilation in the leaves of various plants give values varying from 4.4 103 to 5.2X103 gram calories. Quantitative measurements of radiant energy in relation to the leaf are based on the assumption that the total radiant energy falling upon the leaf is disposed of in the following ways: (1) reflection from the leaf surface, (2) carbon Le (3) transpiration, (4) transmission through the leaf, (5) thermal epee and EscoMBE (1905) disregard (1) in their calculations. The reviewers believe that this is not negligible, since even a black cloth may reflect I per cent of the radiant energy incident upon it. PwuRIEWwITscH (1914) has estimated (2) in a few cases by measurement of the increased heat of combus- tion of the leaf per unit area. His highest value was 2.6 and his lowest 1.3 per cent. On the basis of these he calculated other cases, getting as high as 7.7 per cent. Brown and Escomse calculated (2) by assuming that one gram of absorbed CO, is equivalent to 0.64 gram of dry matter formed, and that the heat of combustion of the products of assimilation is 3.76103 gram calories, The accuracy of these assumptions is not confirmed by measurements. Their computed values vary from 0.42 to 1.66 per cent. All of the evidence at hand thus indicates that only a very small percentage of the radiant energy received by the leaf is actually used in carbon assimilation. It might be expected that the proportion of the sun’s energy used in assimilation would vary inversely as the intensity of the illumination. This expectation is not justified by the experimental data, and it is clear that we must look for some other factor on which no data are given. The reviewers point out here a case of lack of correlation of effort by investigators. If Purrewrrscu had taken cognizance of BLAcKMAN’s researches, his experiments (although regarded by Purrewitscu himself as preliminary) might have yielded results of much greater significance. The energy used in (3) was arrived at by Brown and Escomse by determining by weight the amount of transpiration and calculating the energy used from the heat of the vaporization of water at that reviewers vary but little, the highest being 35.32 and the lowest 35.28 per cent. It is evident that (5) will usually have a positive value, since the 520 BOTANICAL GAZETTE [DECEMBER temperature of the leaf is usually higher than that of the air. If, however, the temperature of the leaf falls lower than that of the air, the leaf will gain energy from the air, that is, thermal emission will be negative. Brown and EscoMBE’s values for thermal emission are based on the same set of experiments as the data quoted under (2), (3),and (4). They areall positive. The smallest one is 6.0 and the largest is 54.60 per cent. Brown and EscomBe were the first to attempt to obtain a complete balance sheet for the leaf in regard to energy. Further quantitative data correlating the work of BLACKMAN, BRown and EscomBe, and PurIEwItTscH are greatly to be desired. We still have no reliable data on which any conclusion can be based as to the relative efficiency of the rays in the different portions of the spectrum. e reviewers mention the early work, indicating that the maximum assimilation takes place in the red part of the spectrum and that there is a secondary maximum in the blue-violet end as being now of only historical interest, since the methods of measuring energy were unsatisfactory and the measurements of assimilation were crude. The work of Knrep and MinbeEr (1909), indicating that blue and red light of the same intensity produce the same assimilation and that the green light is incapable of producing assimilation, is rejected because they give no data relating to any factors other than light intensity, hence some other factor may have been a limiting one. They also reject TIMIARIZEFF’S (1903) data on the absorption of energy by chlorophyll, since he worked with alcoholic extracts, which must have contained less chlorophyll than impurities. The work of Brown and EscomseE on the absorption of radiant energy by the white and the green portion of a leaf of Negundo aceroides is also rejected, since it is considered unfair to assume that the conditions in the green and the albino parts are the same except for the presence of chlorophyll. Werr1cERT’s (1911) conclusions on the efficiency of the assimilation system are considered unreliable, since they are based on the work of Brown and EscomBe just mentioned. The reviewers introduce their discussion of theories of carbon assimilation with a sweeping condemnation of theories, making the point that those who have contributed the most valuable data on this subject have not suggested any theories. They cite DE SaussurE, SAcHS, PFEFFER, and BLACKMAN as examples. They might possibly have added SpoenR to the list, but they could not have added WittstAtrer, since his data on the pigments of the green leaf are certainly very eS pas considerable space is given in their review to the discussion of his theor course blind following of a fa does not lead to progress, and the desirable attitude is that of seeking for facts regardless of their bearing on any theory, but to assume that none of the workers (except SPOEHR) have been influenced by dissatisfaction with the theories that have been advanced seems unwarranted. It is not the right use of scientific imagination that is to be condemned, but the acceptance of mere imaginings as facts. JORGENSEN and StiLes, of course, are quite right in their condemnation of whatever 1917] CURRENT LITERATURE 521 tendency there may have been in textbooks to present BAYER’s hypothesis as representing facts. ey discuss the theories and suggestions of four men: (1) the well known theory of BAYER involving formaldehyde as an intermediate product; (2) the suggestion of vAN’T Horr that assimilation consists of two parts, a photo- chemical reaction and an enzyme reaction; (3) SIEGFRIED’s suggestion that carbon dioxide may form carbamino groups with the protoplasm of the plant cell and that the photochemical reaction may then occur in a complex carbon compound; and (4) WiitstATrerR’s theories which, so far as they are new, are regarded by the reviewers as rather wild, the most reasonable one suggested by him being merely a repetition of SIEGFRIED’s suggestion. In the end it appears that we have at present no satisfactory theory of the changes that take place between the entrance of CO, into the plant and the production of carbohydrates. Although deploring the lack of coordination among the various workers, and the tendency of botanists to accept without question the suggestions of physicists and chemists as to the nature of plant processes, the reviewers con- clude that plant physiology is developing into an exact science, utilizing the experiences of the fundamental sciences, physics and chemistry, but having working principles and methods of itsown. That it will thus be of great service in plant production requires no prophetic vision.—GrEorGE B. Rice. Studies on oxidases.—In connection with his work on plant oxidases, BuNzELL’ has published results of an investigation of the effect of hydrogen- ion concentration, Ch, on oxidase activity. Using his own simplified oxidase apparatus to measure oxidation and the gas chain to measure hydrogen-ion concentration, he finds that the oxidase activity of several kinds of material from potato tubers is completely inhibited by a Cn of 2.0-2.8X10—4. The various concentrations were obtained by adding sodium hydroxide and acetic acid in various Ae ng or either one alone, to mixtures of the plant material and pyrocatec It is worth noting ae that the two together constitute a true buffer solu- tion capable of maintaining a fairly constant hydrogen-ion concentration, but that neither one alone suffices. Consequently, if there is a tendency for the acidity to increase in the Bunzell apparatus, as suggested by Rose® in 1o15, conditions are not comparable in the different mixtures. Those containing the true buffer solution will have practically a constant Cp throughout the course of the experiment, while those containing only sodium hydroxide or acetic acid will have a Cp which is larger at the end than at the beginning. The 7 BuNZELL, H. H., The relationship existing between the oxidase activity of plant juices and their hydrogen-ion concentration, with a note on the cause of oxidase activ- ity in plant tissue. Jour. Biol. Chem. 28:315-333. 1916. 8 Rose, D. H., Oxidation in healthy and diseased apple bark. Bor. Gaz. 60: 55-65. 1915. 522 BOTANICAL GAZETTE [DECEMBER latter condition holds true also for the controls; containing only water, pyro- catechin, and plant material. Furthermore, if the Ch changes during the experiment and only the initial couichateation is determined, as in BUNZELL’S work, no very accurate conclusion can be drawn as to the effect of this factor on oxidase activity. BunzELt finds the inhibiting concentration for tulip tree material to lie between 1.58 and 5.02X10~3, and for the magnolia between 3.5 10~3 and 8.91X10—4. He considers that his results show “that the acid sensitiveness figure is a rather fixed number for any particular genus.”’ He says also that it even seems “that the acid sensitiveness constant is the same or nearly the same for different genera (tulip and magnolia) of the same family (Mag- noliaceae).” An analysis of his table III shows in general that the less the natural acidity of the plant material the lower the Cy necessary to cause total inhibition of its oxidase activity. This relation does not seem to hold in all cases, possibly because the various degrees of acidity used were too far apart to establish the inhibiting concentration with any great degree of accuracy. If further work should prove such a relation general, new force will be added to the suggestions of BUNZELL and others that there is a distinct oxidase for each plant or group of closely related plants; not necessarily because they are protein in nature, however, as BUNZELL supposes. They may resemble each other in plants of the same family; they may show various properties of proteins, such as denaturing by acids, alcohol, and heat, and still be something quite different from proteins. BAYLIss suggests, on the basis of work by BACH and Cuopat and others, that oxidases are merely some form of iron copper ot manganese kept in a disperse condition by various colloids. If these colloids are proteins the action of acids, for example, removes them as dispersing agents and allows the oxidases to precipitate. As a result of absorption, the two may come down together as a single precipitate which gives both protein and oxidase reactions without ever having existed as a real compound in the living plant. Such a hypothesis, however, fails to apply to peroxidases, for these, according to BeHrinc, Aso, and BacH and CHoDAT, are very little affected by heat. Bacx and Cuopar also found that horseradish peroxidase when carefully purified contains no iron or manganese. In connection with BuNzELt’s “acid sensitiveness figure,” the question arises whether the inhibition he noted was all due to acidity. When a buffer solution of any sort is used to establish a definite hydrogen-ion concentration, elements are added which in the quantity used may be entirely foreign to the plant and productive of anomalous results. Illustrations of this are seen in Bunzetr’s table III. For example, extract of potato peeling with a natural Cn of 1.021076 (no buffer solution being present) caused 22 per cent more oxidation than the same extract when a buffer solution was present and the Ch practically the same (1.04X10~®). Even more marked are the results with potato sprouts, for with the Ch just about the same whether the buffer solution were present or not, they gave 16 per cent more oxidation without 1917] CURRENT LITERATURE 523 jt than with it. The data presented for ‘‘tulip tree leaves 1915” and “scaled tulip tree buds” show that when the solution in the oxidase apparatus had the natural reaction of the plant material, the oxidations were respectively 6.6 nd 12 per cent greater than when the Cn, established by a buffer solution, was actually less than the natural Cn. In such a case it seems evident that some factor other than the hydrogen-ion concentration was effective as an inhibitor. The possibility that other ions play a part is indicated by work now being carried on by KRAYBILL and the writer. The paper concludes with a brief review of the evidence, obtained by BUNZELL and others, of an increased oxidase activity in the leaf tissue in the case of physiological disturbances, and the possible meaning of such an increase. No mention, however, is made of work by RosE on healthy and diseased apple bark in which it was shown that there is a much greater oxidase activity in the latter, sail with a lower hydrogen-ion concentration. 9 in a paper published about the same time as BUNZELL’s, puts the inhibiting Ch for oxidase of potato extract at 5.5x10~4 (slightly higher than the 2.0—2.8X10~4 found by BUNZELL), and for that of Red Astrachan apples at 5.0—7.0X10—4. His statement that these concentrations are much lower than those given by previous investigators fails, however, to take account of BERTRAND’S report’? in 1907, that a n/s5o00o solution of sulphuric acid (Ch= 51074) completely inhibited oxidation by sap of the lac tree. REEp’s results would have meant more if he had measured oxidation by the BUNZELL appa- ratus rather than by the relatively inaccurate method of noting color changes, even though the BUNZELL apparatus, because of the poorly understood effects of hydrogen-ion and other inhibitors, leaves much to be desired in the way of accuracy, One point is well made in this paper, namely, that plant extracts have an acid absorbing power which must cause inaccuracy in interpreting results obtained by adding buffer solutions to them if such results are not checked by careful determinations of the cab ig al ape ranean He found that when a given volume of 0.01 molar HC added to an equal volume of potato extract, the hydrogen-ion ican rg which should have been 5X107—3 if the potato extract acted like water, was actually only 51074, This decrease in acidity he thinks is due to riecteise present in the extract as well as other amphoteric electrolytes, including probably phosphates and carbonates. It is unfortunate, to say the least, that the authors of these papers have failed to cite adequately the literature pertinent to the phase of the subject with which they are dealing. Each has made a definite contribution to our 9 Reep, G. B., The relation of oxidase reactions to changes in hydrogen-ion con- centration. Jour. Biol. Chem. 27: 299-303. 1916. © BERTRAND, G., Bull Soc. Chim. France 1:1120. 1907. 524 BOTANICAL GAZETTE [DECEMBER knowledge of the factors affecting oxidase activity, but the true value of this contribution would have been better shown by a fuller reference to other work. STLE and BUCKNER" report experimental proof that phenolphthalein can be oxidized in the living plant. This they take to mean that free active oxygen is present in the tissues, apparently overlooking the possibility that combined oxygen might have caused the results observed. The reagent used, on oxidation, yields phenolphthalein, which is easily recognized by the pink color it gives with alkalies. When this test was applied to stalks of Indian corn which had been injected with the reagent, the pink color was found local- ized in the fibrovascular bundles of the stem and leaves. It was not found in the tassel, although lower down, close to the point of injection, there had been some diffusion into the cells adjoining the fibrovascular bundles. Similar results as to place of oxidation were obtained with okra. The method here used offers a means of attacking the problem of oxidation in plants which should yield other valuable results if further developed and applied to a wider series of plants. It would be worth while to try whether phenolphthalein can be oxidized in the living plant when used in neutral or acid solution, and if so whether the oxidation is localized in particular cells or tissues. Such a test would allow for the effect of reaction (acidity or alkalin- ity), a factor known to be of great importance, not only in oxidation processes, but also in other processes carried on in living tissues. The effect of reaction might also be studied in acid fruits and in tissues affected by “physiological diseases’’ or by diseases due to bacterial or fungus parasites. In several cases such tissues have been found to be less acid than healthy ones, but little is own concerning variations in reaction within the tissues themselves.— D. H. Rose. Experiments in girdling.—A contribution by HrB1No” is of interest both to plant physiologists and horticulturists, since it will aid in furnishing a more definite chemical basis for the interpretation of the behavior of girdled plants. In the past there has been no lack of references to the accumulation of elabo- rated foods above the girdles; it is certainly worth while to have some definite determinations of these compounds and their relative quantities. Five types of girdling were tried on Cornus contraversa Hemsl. These con- sisted in (1) removing a complete ring of bark, (2) removing a complete ring of bark and some of the wood, (3) removing half a ring of bark, (4) removing half a ring of bark and wood, and (5) boring completely through the wood. The wounds were left unprotected. The last three methods of treating the material resulted in responses similar to the untreated controls in nearly all cases. The genera] external results noted are those commonly recorded in girdling experiments. The main interest of the present paper centers in the presenta- Kastte, J. H., and Buckner, G. Davis, Evid { the action of oxidases within the living plant. tone Amer. Chem. Soc. 39:479-482. HIBINO, Sutn-Icut, Effekt der Ringelung auf ie eae bei Cornus controversa Heil: Jour. Coll. Sci. Imp. Univ. Tokyo 39:1-40. pls. 1, 2. 1917- 1917] CURRENT LITERATURE 525 tion of material which may aid in an explanation of the cause of these condi- tions. Unfortunately the experiments are limited and the analyses of the nitrogenous compounds are not sufficiently complete to furnish any sort of basis for judging what réle they may play. The data on the carbohydrates, however, are of considerable interest. In studying the effects of girdling on nutrition in general, at least three of the many points concerned in growth must be considered: (1) a possible modification of the intake of nutrients by the roots; (2) the synthesis of products from these compounds and those resulting from photosynthetic activity; and (3) whether these compounds are stored or utilized. We are given some light on the third point only. It is a fair question to ask whether the ability of the roots to take up salts is not as pro- foundly modified by the character and quantity of the organic nutrients in the parts above ground and with which such salts may be combined, as it is by the so-called starvation effects brought about by cutting off the supply of organic nutrients from the tops to the roots. Girdling could pring about _ en cet Situations. The question arises as to why the the girdles. As commonly stated, this may be due to the fact that these products are held from passing into the roots. There is little evidence which would show that it may not also be due to a deficiency of mineral nutrients, particularly nitrates, to aid in their utilization in forming other compounds or growth. study of the ratios of carbohydrates to moisture, nitrogenous . compounds, and other mineral nutrients in their relation to the entire phe- nomenon of growth is greatly to be desired. While this situation is not dealt with by Hrsrno, his results and those of several previous investigators furnish ample encouragement to warrant investigation. The increase in anthocyanin accompanying an increase in reducing sugar confirms the findings of previous workers with other plants. The yellowing of the foliage above a girdle is a usual condition. That this should accom- pany an increase in carbohydrates is interesting. It is unfortunate that no analyses of the nitrogenous compounds in the leaves are available. Lacking such determinations nothing can be said concerning their possible relationship to the carbohydrate situation, nor the moisture situation. The fact that the percentage of moisture in the leaves is lower when carbohydrates form a higher percentage of the weight might be expected when the moisture holding capacity of these compounds is considered. The single quantitative determination of the reserve materials in the twigs in midwinter is not sufficient for any general conclusions. Again, it is unfor- tunate that all the nitrogen is computed as protein. It is more than likely that all of it is not, and quite probable that the several forms of nitrogen may exist in different proportions in the several lots examined. A quantitative analysis at the time of active vegetation would have been even more significant regard- ing the influence of the several substances on growth. Striking as are the differences in the several lots, the results cannot be interpreted with certainty unless compared with figures for similar parts at several periods during the 526 BOTANICAL GAZETTE [DECEMBER year. Whether the differences shown by the bark and wood girdled material may be accounted for by a decreased moisture supply in the latter is an open question. It is interesting to note, however, that many plants grown with a deficiency of water do show an increased tannin content. e it is impossible to draw broad conclusions from the results pre- sented, the work constitutes a genuine contribution toward a more nearly complete knowledge of the causes of the responses following girdling, and adds to the available information on the entire problem of growth. In any future work it would be particularly desirable to follow the nitrogenous compounds and mineral nutrients as well as the carbohydrates, more especially with a view toward the determination of the ratios of these various substances in relation to the observed responses.—E. J. Kraus Imbibition—MacDovucaL® and MacDovucar and Spornr™ are doing work on the effects of acids and bases on imbibition of water by plant tissues and plant gels that promises to be the most significant contribution in this phase of plant physiology that has been made for some decades. Practically all of the work on the effect of acids and bases on the amount of swelling and force of swelling of gels and on the viscosity and osmotic pressure of sols has been done on the amphoteric protein gels. For these it seems well established that the iso-electric point (the reaction at which the particles are without a charge) is the point of minimum swelling, force of swelling, osmotic pressure, and viscosity, and that forcing the ionization of the gel or sol either to the posi- tive by addition of an acid or to the negative by the addition . a base increases the swelling, osmotic pressure, and viscosity very markedly. MacDovceat and Spornr find that both base set acid aii (n 0.01) decrease greatly the swelling of agar plates and to a less degree of Opuntia tissue. In fact, Opuntia tissue acts more like mixtures of gelatine and agar than it does like either gelatine or agar. These results suggest that in con- trast to the protein gels and sols, the point of maximum swelling, viscosity, etc., in agar is the iso-electric point and that the positive agar due to acid addition or the negative agar due to base addition shows a lowering of these characters. In this connection it is to be regretted that the H+ concentration for the iso- electric point of agar has not been determined. It is also desirable to know the behavior of various other carbohydrate gels and sols (mucilages, pectic materials, gums, etc.) to see whether this contrast in behavior is a general difference between the protein and carbohydrate gels. It seems that plant physiologists have generally assumed that the laws of behavior of protein % MacDoveat, D. T., Imbibitional swelling of plants and colloidal mixtures. Science 44:502-505. 1916. ™ MacDoveat, D. T., and Spornr, H. A., The behavior of certain gels useful in the interpretation of the action of plants. Science 45:484-488. 1917 *s Hoper, R., Physik. Chemie Zelle Gewebe. 329-338. 1014. 1917] CURRENT LITERATURE 527 colloids hold for all hydrophilous colloids with which they have to deal, protein as well as carbohydrate. This work seems to make evident the error of such a general assumption. A quotation from the last paper gives the author’s view of the physio- logical significance of these results. ‘‘The general identity of constitution of these colloidal mixtures and of cell-masses, and the obvious similarity of their behavior, together with newly determined features of carbohydrate metabolism not described in this paper, make it possible to correlate more closely the processes of imbibition, metabolism, and growth, and on the bases of these interrelations, to pherpret ares enlargement and incidental varia- tions in volume and size of organs.””’ No doubt many will differ from a state- ment in another part of the paper that amorphous carbohydrates form a very important part of the plant protoplast. There seems little evidence that carbohydrates are constituents of the protoplast they generally appear as discrete particles of micronic size and not in intimate mixtures with proteins and distributed in particles of submicronic or amicronic size, as must have been the case in the agar gelatine 2 i with which the authors worked. late we are coming to know that amorphous carbohydrates of the walls and intercellular spaces have sudiahe physiological controlling action. is is especially true in s. is work is very suggestive in this connection so. This work may have a very important bearing on the daily transpiring power of certain of the cacti as found by various workers in the Desert Labora- tory. In these there is apparently no stomatal regulation, and the lowest transpiring power is during the day. This corresponds to the daily change in acidity. The time of low transpiring power is the time of low acidity, when, according to the findings of MacDovucat and Spornr, the gels of the tissues will have the greatest power to take up and hold water. With this no doubt there will be a rise in viscosity. These physical conditions will all tend to lower the rate of movement of water toward the intercellular spaces and to lower the vapor pressure within those spaces. This in turn will lower the rate of outward diffusion. This suggested relation needs careful investigation. On the basis of the behavior of protein gels the daily variation in the transpiring power of the cacti was not intelligible. This work should be a great stimulus to much work along similar lines —Wa. Croc Taxonomic notes.—BritTon,” in continuing his studies of West Indian plants, has described new species in Cleome, Chamaecrista (3), Leucocroton (3), Passiflora (3), Rondeletia (10), Eriocaulon (3), Dupatya, Pilea, Ichthyomethia, % Britton, N. L., Studies of West Indian plants. IX. Bull. Torr. Bot. Club 44:1-37. 1917. 528 BOTANICAL GAZETTE [DECEMBER Castelaria, and Stenostomum (2). There is a synopsis of the species of Chamae- crista in the West Indies (31 spp.); of the Cuban genus Leucocroton (7 spp.); of Passiflora in Cuba (21 spp.); and of Rondeletia in Cuba (35 spp.). Dr CANDOLLE,” in a study of specimens of Meliaceae from Central America | and Panama sent by the United States National Museum, has described 9 new species in Guarea and 2 in Trichilia. Hepccock and Hunt® have described 5 new species of Peridermium on pine needles in the eastern United States RN, in a monograph of the North American “sedge rusts,” recognizes 19 species of Puccinia, 3 of which are described as new NELL,” in continuing his studies of our southern plants, has presented the genus Chamaecrista as represented in the United States. He recognizes 13 species, which include 3 new species and 2 new combinations. WaceEr* has published a list of the mosses of South Africa, which for the first time brings together all the known mosses of South Africa. The list includes 846 species in 160 genera, representing 37 families. The names of 27 new species, representing 23 genera, are also included, one of the genera (Physcomitrellopsis) being new. These will be described and published later. ILLIAMS,” in reporting the mosses obtained on a collecting trip in - ser te ae ee ay October 1903 to August 1905, lists 2 species in , 27 species and 3 agi hades, y Sear casmnaloain are desis as new.—J. M Endosperm color in maize.—In crosses between California Golden Pop maize and a white endosperm ey obtained from Haace and Scumipt under the name Zea Caragua, WurrE* finds white dominant. These results are interpreted by assuming the presence of an endosperm suppression factor A in the Zea Caragua in addition to the usual color factor y. , This new primary factor affecting endosperm color raises the number of such factors to three; in addition there are numerous secondary factors.—E. M. East. DeCanbotte, C., Meliaceae Centrali-Americanae et Panamenses. Smithson. Miscell. Coll. 68:no. 6. pp. 8. 1917. * Hepccock, Gro. G., and Hunt, N. Rex, New species of Peridermium. Myco- logia 9:239-242. 1917. ? Kern, Franx D., North American species of Puccinia on Carex. Mycologia 9: 205~238. 1917. * PENNELL, Francis W., Notes on plants of the southern United States. II. Bull. Torr. Bots Club 44:337-362. 1917. * Wacer, H. A., A check list of the mosses of South Africa. Publ. Transvaal Museum, Pretoria. pp. 20. 1917 * WILLIAMS, ingens S., Philippine mosses. Bull N.Y. Bot. Garden 8:331-378- pls. 171-174. 19 3 WHITE, be aks E., Inheritance of endosperm color in maize. Amer. Jour. Botany 4:396-406. 1917. = GENERAL INDEX Classified entries will be found under Contributors and Reviewers. New n and names of new genera, species, and varieties are printed in bold face ses synonyms in #talics. A Abutilon, resistance of seed coats to in- take of water 166 by Hoang 3 Addiso mi keropeeo Algae, of Michigan Alkalies and ans absorption 346 um 84; permeability in 509 Alnus Ferdisandl Cohecett 147 Amani Amsinckia 446 Andrews, E. F. 497 rasoane) 79s eurycarpa 81 Anthoc Apog: ae ih aceores and Osmunda 435 Appleman, C. O. 349; work of 351 bis 440 Arber, Agnes, work of 350 Archegonium of Cath: W. R. G. peeiogy 82: work of 256 Atkinson, G. F., work of 340 B Balsamorrhiza, resin secretion in 441; connata 33; cornu illeniana 30; frondosa outa 343 | Holwasi 395 hu- 33; Langlassei 24; leptoc 22; mollifolia 21; Palmeri , 29; sends: lausensis 26 Figen 35; sambucifolia 40; Seemann 27; —_ osa 35; tenui- secta 30; tipartin Blackburn, Kathleen 3. work of 350 Blake, S. a ¥ seonk ol-a9p Blandibra Boerker, RH j: apa of 351 529 n, E. Pe Bg of 257 seein: sourquin, Hide 426 sovie, W. T., — of 342 pase: F. O., work of 347 ay, W.L., reek of 88, 352 reazeale, J: P., work of 346 rickellia uckne r, G. Dye work of 524 ulbiferous fungi 265 nzell, H. H., work of 521 tae See ’ work of 2 257 surns, =e Py work of » 264, 352 surt, E. A., work of 8 Seesd Weed head benad: Ieeal bi ie Calcium ce ae of soil 347 Caldwell, J. S., work of 87 Cambium in m monocotyledons 350 Campylogramm Carbon steitaiiation aed Car e 261 arex 84, 261 Cassia 1 aie we a" of 1 Cephalanth hamaecrista 174, bes mberlain, C. I Cc Be Cc hinese seo 70, I as Ch osomes, number of 171 Cc cS Co me s leaves, mottling i in 343 eome ker, Ww. ©, work of 439 Colo: ills vegetation in 353 Coniferous fevestn: oe ee in 149 coun An drews 497; Ap- 480; i Cierabinicin, c 27s Cae M. T. 53° 345; Coulter, J. M. 83, 87, 255, 260, 349, 343, 347, 359, ie "352, 439, 516, 527; Coulter, M. C. 263; Crocker, W. 82, 84, 168, 172, 343, 344, 346, 347, 349, 526; D E. 166; Dupler, A 87, 88, 176, 253, 254, 262, 263, 264, “85, 348, 350, 351, 3525 Harris Laura 318; sal ~ Ws 1935 tris, J. A. 285; Harvey, R. B. 342; Hasselbring, H. ' 169, 176, 262, 337, 3493 Hotson, J. W. 265; Krau s, E. J. 524 ; Kraybill, H. R. 423 eiernadg dN. ys Long, W. H. S73 ir, J. B. 330; McNeill, J. 318; Macbride, J. F. 79; MacCaughey, V.8 : M.S. 177; 9, 386; Markle, ‘ re, B.149; Payson, E. B. be Record, S. J. 437; Riddle, L. W. 513; Rigg, 438, 516; Ro an $F ra oi. Rumbold, Caroline 250; Sawyer, M. Louise 159 Sawyer, W. H., Jr. 206; Schneider, C 70,137; She Shull, Wuist, ra D.4 Cook, M ee Cordia Conooky tani 440 Cosmos Landii 29 Cotoneaster he Hero 70; Vernae 71 Coulter, J. M. 83, 87, 255, 260, 340, 343, 347, 35°, 351, are 439, 516, 527 Coulter, M. C. 2 Crocker, W. os, ay 168, 172, 343, 344, 346, 347, nt 526 Crown gall 33 Culpepper, e W., work of 86 Cuma ola 440 Curtis, K. M., work of 352 Cyanea 261 D Darwin, F., work of 172 ed cake ae — of 349 DeCandoll ce an of 528 Derbesia Desert Plats, root systems of 177; the variable Diehl, W. wo ens of 170 iseases, fruit Dodecatheon 44 Doles Mis ¢ é. E., work of 340 Duar B. M. work of 169, 170, 176, 349 Dupatya 1 ery A. W. 1 Dyes, effect on Endothia 250 INDEX TO VOLUME LXIV [DECEMBER. E East, E. M. 5 Enc meee ny mutation theory ni Enc ophiylloides hd 5 Endophyllum Endosperm tick ta ize 528 Enc — parasitica, ge oe of dyes on Epiphytc — anatomy of 352 Era Erigeron Eri ns . ° honk of 169 174 i . of 345 Evans, A. W., work of 260, Evaporation pa from Galt. Coast 318 Everett, A. E., 7 256 Extinction, i in ‘Hawaii F Farrow, E. P., — of 263. Fernald, "M. 1 work of 33, 261 F “ea phylogeny 0 of 3 Ficu eee; in ccceacin of nia eer oie 497 Fomes, peculiar spore distri 261 ‘00 Free, E. E., work 0 Fruit classe: 2543 seek of fungi on 86 Fuller, G. D. 85, 87, 88, 176, 253, 254; 262, 264, 347, 348, 350, 351, 352 Fungi, enzyme activity of 175 G Galls 3 ace of Taxus canadensis 115 ano, Laura ra 31 Gardner , N. L., work of 44: work of ee Oe, 34° Grasslan eath 2 Greenman, J. M., oti a 83, 175 Gulf ‘Conit, evaporation ion records from 318 1917] H Haas, A. R. Dak ted sed se Hagstrém, % O., Harper, Harris, J A. 28 5 Harvey, R. B. 342 Harr tris, J. A., work of 264, 345 Hasselbrin, g, H. oe 176, 261, 337, 3493 work =: 173, I Hawaii, =e ax of 89; vegetation of lava ows 386 Hawki ig te work be 86, 173, 174 Heath ou grassland 26 Hedgc aia NG G., work ~ 528 Herberta Hesler, L. z ‘Manual of fruit diseases” 254 Spina S., work of 524 Hier Hildebrandt, _F. M., w of 526 Hunt, N. R., work of 528 I Ichthyomethia 174 Imbibition 526 Ishikawa, M., work of 171 J n, C. A., work of 343 restry 262 K oeaard { ies vo of 256 > > we sacri L., work of 344 Koidzumi, G., work of 341 Kraus, E. J. 524 Kraybill, H. R. 42 INDEX TO VOLUME LXIV L ae J. V. 285; work of 345 174, 528 Leuc : Tichéda, coy 264 Li um n, B. a wo Lloyd, T t., “The Ie of inland waters”’ 2 Long core 2 gare of 176 Long, W. H M McBeth, I. G., work of 3 McClendon n, J. RF. Physical chemistry of vital phenomena” 438 McNair, igs 330 M - 318 Macbride, y. F, eet work of 440 acCaughey, V. 89, 386 Martins in T a i of 526 e, K. K., ’ work of 84, 261 Maize, endosperm color in 528 Mallison, H., work of 256 Marattiaccac, mycorhiza of 350 Marchantia 260 Markl : MS. 7 Matz, J., wor 171 Meinecke, E. P Ps work of 3 woe “ion f Cen tal” aA ceed and a 52 28 Meliola t types, Spegazzinian 421 Mertensia 440 Microchaete 83 ilti ° onocotyledons, eT in 350 Monocotyledony 34 Moore, B. 1 Moore, S. LeM., work of 341 Morus 34 Mosses of Sou rica 528 Mottling in citrus leaves 343 Mucor 341 Murrill, W. A., “North American flora”’ 516; work of 255 5 and endemism 263 Mycorhiza of Marattiaceae 350 N Nagai, I., work of 260, i Nakai, T. work of 15) 3 Needam nS h re “The ‘ite of inland se waters ud Neobertie Nesareniin ¥ Holwayi 67 ) 532 New York, Le pion of 352 Nitrogen, = 349; sstatioih of semi- arid so North Miran flora 255, 516 O Oenothera 175 Olive, E. sti nig of 175 Cnneiucdie Organic nutrition of plants Osmotic re in PPS ne host 345 Osmunda, a apogamy i 435 Otis, C. H., work of 88, 352 Oxidase Ses 5 r ie tere a oe 273; byssina 270; pallidula 268 ; nigra 275; Pupasite me pies osmotic pressure in 345 ioe? ae Passiflor eee icky ie Payson, E. B. 795 work e 341 Peltier, = L., work of 1 Pennell, F, W., Tata of oes, 528 w method of studying 306; of cal wails of Allium 509; of pro- ete dh 3 Petalostemum 440 Phacelia Phaes Phegopte Say Sgeoatiet phe aimed of 206 Phot rain = of dust on 349 Somat: trichum t, F. L., work of 351 Pilea 17 Pine, Hepa of Virginia and the wera —— of longleaf 49 Pis tillart Plant a iay. Se to 168 Platanus, w 480 Po lakiastru 175 Pollen cakes and i ia es ak Iris 159 Polygonatum 34 Potamogeton ae ease iy of 230 Prunus latidentata trichostoma 72 Pseudopohlia 528 Puccinia 528 INDEX TO VOLUME LXIV [DECEMBER Pulling, H., work of 168 Pyrenothrix nigra 513 Quercus alba, ray tracheids in 437 R nales one anatomy of 3 ae 64 Re Jason in ucts es 437 ecor A377 eh G. B., work of 523 en , work of 175; 261 Resin pects Respiration 351; 4 Reviews: Atkins’ ] rrhiza 441 _ effect of sin sre dioxide “Researches in plant H Romeli, L., Rondeletia 54,53 t, of Balsamorrhiza 4 52; rot of Texas eee systems of desert plants 5 R 84; landulosa 75; Maire plurijuga 743 — yunnanensis 77 Rose, D. H. 521 Rubus ‘eatictan 73 Rudbeckia Rumbold, Caroline 250 Russula 440 Rydberg, P. A., work of 84 5 Salix Balfouriana 137; brachista 144; caloneura I41; dibapha 146; Faxon- iana 143; tiana 139; ener Guebrian rosa 142; tenella 137; wolohoensis 14 1917] Salt, absorption and alkalies fire-h olding capacity of tobacco 4 and dunes of Michigan 348 anford, , Wo chneider, C 70, 137 eedling epneted of Ranales 350 enecio 83, equoia, iossil “rom Japan 352 herff, E. E. 2 hibata, K.. work of 256, 260 hibata, Y., ork of 256 hull, C. ae 86, 344, 351 ipane Mare mith, E ¥., his of 337 ith, ork of 341 mit oil, calcium compo ounds of 347 u vegetation ig 85 permatogenesis, Tris piro 28 staged 8 526 pore distribution tandley, P. C., nieces 255, 440 tarch formation in Z ygnema 426 t Balsamorrhiza 455 Stenostomum 174 oe — Ss, Fo ke 2 bay R. fee work. o 350 tiles, W., ork of 5 tomatal regulation ae tropharia weet potatoes ee storage 173 ycamore woods, North American 480 PA TATA rA é & ' Tapetal nuclei, wandering 351 Taxus canadensis sis, gametophytes of 115 Ea bh oe and viability Tephrosia 175 Tidestrom, I., work of 8 ioe fluids, carcecbic determinations 285 hacen fire-holding capacity of 42 of 168 Tottin gha am, W. E., work Transeau, E. N., work of , W.G., k of a, Travis, W wor Trelease, S. F., work of 16 Trees, of Pennsylv sah 35: of Vermont 352; tolerance of 2 INDEX TO VOLUME LXIV 533 3465 | and Trillium 83 Tropical vegetation 87 Truttwin, H., work of 256 Turriculs 440 V ge? Aide ers C. R. W. K., work of Veronica 440 Vestal, ve Gers Viability and temperature 34 Viburnum, calvu seh 78; dricum scadelfosints 77 cylin- W Wager, H. A., work of 528 Waggon er, HL a work of 344 Weil Williams Willstitter, R., work 0 Woodhead, Z i W., “