THE BOTANICAL GAZETTE THE UNIVERSITY OF CHICAGO PRESS CHICAGO, ILLINOIS Agents THE BAKER & TAYLOR COMPANY NEW YORK THE esetinestaty ie UNIVERSITY PRESS AND EDIN o KK] . \ Baer THE eS BOTANICAL GAZETTE EDITOR JOHN MERLE COULTER VOLUME -LV JANUARY-JUNE, 1913 WITH TEN PLATES AND ONE HUNDRED AND THIRTY FIGURES vio. Bot. Garden 1913 THE UNIVERSITY OF CHICAGO PRESS CHICAGO, ILLINOIS Published January, February, March, April, May, June, 1913 Composed and Printed By The University of Chicago Press Chicago, Illinois, U.S.A. TABLE OF CONTENTS The climax forest of Isle Royale, Lake Superior, and its development. I. Contributions from the Hull Botanical rarer otes - (with map and fourteen figures) - - William S. Cooper Progressive and retrogressive ‘iene 3 in the plant associations of the Delaware Coast —_ six gure - Laetitia M. Snow Ray rackeuds in te Coniferater (with plates 1 I and II) - Ruth Holden The life history of eubeiecneo (with a 1) - Edgar N. Transeau Hydrodictyon africanum, a new species. Contribu- tions from the Hull Botanical career’ 166 (with six figures) - - Shigéo Yamanouchi Revegetation of a denuded area (with two beaies) H. S. Conard The morphology of Araucaria brasiliensis (with eleven figures and plates IV and V) - L. Lancelot Burlingame The climax forest of Isle Royale, Lake Superior, and its development. II. Contributions from the Hull Botanical a ee (with sixteen figures) = - - - William S. Cooper Macrozamia Moorei, a conheeting link paween living and fossil cycads. Contributions from the Hull Botanical sobs 168 (with twelve figures) . - Charles J. Chamberlain A protocorm of Ophioglossum. Coitribations from the Hull Botanical a 167 aa thirteen figures) - - - L. C. Petry Inheritance of flower size in crosses between species of Nicotiana (with plates VI-X)_ - E. M. East The climax forest of Isle Royale, Lake SEES eid its development. III. Contributions from the Hull Botanical oe sig hes — five figures) - - - William S. Cooper Studies on the phloem of the Ditoryiedind Con- tributions from the Hull Botanical Laboratory 169 (with plate XI and three figures) - - Ansel F. Hemenway Vv PAGE ny vi. CONTENTS [VOLUME LV Paraffin blocks for growing seedlings in — culture solutions (with three figures) Conrad Hoffman The effect-of certain chlorides singly and cies in pairs on the activity of malt diastase - - Lon A. Hawkins A physiological and chemical study of after-— ripening. Contributions from the Hull Bo- tanical Laboratory 170 - - - Sophia Eckerson The California Paroselas (with five fapacs) ke S. B. Parish The effect of some Puget Sound bog waters on the root hairs of Tradescantia— - George B. Rigg Toxicity of smoke. Contributions ‘en the Hull Botanical Laboratory 171 (with four figures) Lee I. Knight and Wm. Crocker Western plant studies. I - ~ Aven Nelson and J. Francis Macbride Sir Joseph Dalton Hooker - - . F. O. Bower The Lichens of Mt. Rose, N a - “Alert W.C. T. Herre Toxic inorganic salts and acids as affecting Ane growth - - « Chas. 2; le and Frank H. Wilson The transpiration of abi leaves infected with Gymnosporangium (with one figure) oward S. Reed and J. S. Cooley Undescribed plants from Guatemala and other Central American Republics. XXXVI - - John Donnell Sesith Vegetative reproduction in an Ephedra. Contri- butions from the Hull Botanical “ecggiaed 172 (with five figures) W. J. G. Land Protoplasmic contractions dosent iccwives which are caused of pure distilled water eg six figures) - -- W.J.V. Osterhout Reproduction by tiseting in the black spruce. ontributions from the Hull Botanical Labora- tory 173 (with six figures) - - i oe George D. Fuller BRIEFER ARTICLES— A simple revolving table for standardizing porous cup atmometers (with one ei aigt - G. E. Nichols Poisoning by Ginkgo - . - Anna M., Starr _ Anew wood-destroying fungus (with six tore} - Adeline Ames A safety razor modified for _ hand sections (with one figure) - - J. P. Givler On Stemonitis nigrescens and related oe - : W. C. Sturgis Thomas Howell (with portrait) - - Huron H. Smith The Seeding of Phyllocarpus (with one cs - -T.D.A. Cockerell PAGE VOLUME Lv] CONTENTS vii PAGE CURRENT LITERATURE- - A - - 85, 167, 252, 327, 402, 461 For titles of book reviews see index under author’s name and reviews : Papers noticed in ‘Notes for Student”’ are indexed under author’s name and subjects DATES OF PUBLICATION No. 1,.January 15; No. 2, February 15; No. 3, March 15; No. 4, April 15; No. 5, May 15; No. 6, June 16. ERRATA Vor. LIV 330, line 9 from bottom, for (fig. 5) read (fig. 3). sy Vor. LV 79, line 7 from bottom, for Yamonouchi read Yamanouchi. 186, .able V, column 5, for 264.4 read 226. 4. 225, legend of fig. 54, for burned read burn. 331, line 9 from top, for C. T. Orton read C. R. Orton. 395, line 15 from top, for Leconora read Lecanora. 402, footnotes 3 and 4 should be interchanged. od THE BoTANICAL GAZETTE Editor: JOHN M. COULTER January I9r3 The Climax Forest of Isle Royale, Lake Superior, and Its Development. I William S. Cooper Progressive and Retrogressive Changes in the Plant Asso- ciations of the Delaware Coast Laetitia M. Snow Ray Tracheids in the Coniferales Ruth Holden The Life History of Gloeotaenium Edgar N. Transeau Hydrodictyon africanum, a New Species Shigéo Yamanouchi Revegetation of a Denuded Area H. S. Conard Current Literature The University of Chicago nis: eo) meena aks ILLINOIS, U.S.A. Ea gi ee ‘ial Agents THE (CAMBRIDGE UNIVERSITY PRESS, London and Edinburgh M WESLEY & SON, L TH. STAUFFER, ae THE Tokyo, Osaka, Kyoto Che Botanical Gazette A Montbiy Fournal Embracing all Departments of Botanical Science Edited by Joun M. Courter, with the assistance of rv members of the botanical staff of the University of Chic s Issued eae 45, ions Vol. LV - CONTENTS FOR JANUARY 1913 No. § THE CLIMAX FOREST OF ISLE ROYALE, LAKE SUPERIOR, AND ITS DEVELOP- MENT. I. Contrisvutions From THE Hurt Botanica, LaBoraToRY x08 (WITH MAP AND FOURTEEN FIGURES). William S. Cooper *- eS ae eee PROGRESSIVE AND RETROGRESSIVE CHANGES IN THE PLANT caneean 0 THE DELAWARE COAST (with srx ricures). Laetitia M. Snow - 5 RAY TRACHEIDS IN THE CONIFERALES (WITH PLATES I AND I1).. Ruth Holden - . = eo THE LIFE HISTORY OF GLOEOTAENIUM (wire, PLATE U1). Edgar N.Transeau - - © oe AFRICANUM, A NEW SPECIES. CONTRIBUTIONS FROM THE HULL Boranicat LABORATORY 166 (WITH SIX FIGURES). Shigéo Yamanouchi - ' REVEGETATION OF A DENUDED AREA (witm two ricures). H. 5S. 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At is advisable eonfer with the editors as to illustrations required in any meee offer a9 Porentyf ive ximate nail of a ditional se > sent 0} aest. ‘ ; d : e. : 4 VOLUME LV NUMBER 1 THE TOL ANICAL. (GAZETTE JANUARY 1913 THE CLIMAX FOREST OF ISLE ROYALE, LAKE SUPERIOR, AND ITS DEVELOPMENT. I CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 165 WILLIAM S. COOPER (WITH MAP AND FOURTEEN FIGURES) Introduction Eastern North America north of Florida and Mexico is divided into two great phytogeographic regions, the eastern deciduous forest and the northeastern. conifer forest. Im each of these a number of lines of succession may be traced, all those of a region leading to a certain forest type as the final or climax stage. This final type in its large features is determined by climate, and is much the same throughout the region which it dominates. In the eastern deciduous forest the climax type is made up of Acer sac- charum Marsh (sugar maple) and Fagus grandifolia Ehrh. (beech), with the addition of various other species in some portions of the country. The nature of the climax forest of the northeastern conifer region has not hitherto been determined. Isle Royale lies just within the limits of the northeastern conifer region, barely within, for one of the farthest outposts of the decidu- ous forest is located on its southwestern end, where there is a considerable area dominated by the sugar maple, in mixture with more northern trees. Except for the maple and a few of its com- panion species, the flora of Isle Royale belongs strictly to the north- eastern conifer region. 2 BOTANICAL GAZETTE [JANUARY The purpose of the present work was to determine the climax forest of Isle Royale, its composition and character, and to trace the various lines of succession leading to it. _ It is thus a successional study of a small component portion of the northeastern conifer forest. : At the beginning of the investigation Isle Royale was selected as a field of study because it shows transitional features between the two great forest regions, my original purpose being to devote particular attention to the relations between the conifers and the maple. Circumstances made it impossible to give adequate study to the region dominated by the latter, therefore the work developed into an investigation of the balsam-birch-spruce forest (the north- eastern climax) and its attendant successions. For a study of the northeastern conifer forest a more centrally located area might have been preferable; for instance, at some point midway between Lake Superior and James Bay. It will be shown, however, that Isle Royale affords a very fair sample of the forest growth of the northeastern region. It also possesses certain very important advantages which would be lacking in a more centrally located area. Because of its insular position the forest has been less liable to destruction by fire, and the many bays and channels separating various portions of the main island and the outlying islets have served as effective barriers against its spread. Though they have occurred many times during the island’s history, it is certain that fires have been far less frequent and destructive here than upon the mainland. The forest may thus be studied in a condition that is as near to being undisturbed as will be found anywhere. Com- parative freedom from the destructive agency of man is a second advantage. Again, the island has had a simple physiographic history during the present vegetative cycle, and thus the relation of vegetation to physiography may be the more readily made out. Further, the proximity of the lake shores permits the observation of the earliest stages in the establishment of vegetation upon the rock surfaces, these stages being frequently absent or poorly developed in an inland locality. Finally, the fact that the field of study is an island gives definiteness to the area covered by the investigation. 1913] COOPER—ISLE ROYALE 3 Headquarters were established at the Park Place Hotel on Rock Harbor (sec. 4, T. 66 N., R. 33 W.), and field investigations were carried on upon the island during the summers of 1909 and ror1o. Most of the detailed work was done in the vicinity of Park Place, but the coast was visited from Hawk Island to Blake Point on the northwest, and from Blake Point to the head of Siskowit Bay on the southeast. Excursions into the interior were made from various points along this stretch of shore. The study was undertaken at the suggestion of Dr. Horny C. Cow Les of the University of Chicago. I wish to express my appre- ciation of his invaluable assistance and co-operation, freely given at all times during the progress of the investigation. I desire also to extend my thanks to Dr. M. L. FERNALD of the Gray Herbarium of Harvard University, who determined all doubtful sperma- tophytes and pteridophytes, and to Miss EptrH A. WARNER of Brooklyn, N.Y., who determined the mosses collected upon the island, about 80 in number. The nomenclature of the pteri- ‘danliptes and spermatophytes is that of the seventh edition of Gray’s Manual. PREVIOUS BOTANICAL WORK UPON ISLE ROYALE A limited amount of botanical work of taxonomic and ecological nature has been done upon Isle Royale. In 1848 W. D. WuItNEvy, acting as naturalist for a government exploring party, made a brief list of plants found upon the island, which was published in the report of the expedition (24) in 1851. In 1890, according to Apams (4), F. E. Woop made a collection of plants in the vicinity of Rock Harbor and presented them to the University of Michigan. In 1901 W. A. WHEELER (58) published a list of noteworthy species, reporting for the first time the strange occurrence of Fatsia horrida (devil’s club) upon the island. In 1904 and 1905 Isle Royale was visited by parties from the Museum of the University of Michigan, both equipped for ecologi- cal work among plants and animals. The first, under the leader- ship of Dr. A. G. RUTHVEN (3), spent three weeks upon the island, after a month’s work in the Porcupine Mountains of the northern peninsula of Michigan. Their explorations were confined to the 4 BOTANICAL GAZETTE [JANUARY southwestern end of the island. In respect to the vegetation the results of this expedition consist in scattered ecological notes and a list of plants including only 91 species (49). The second party, headed by Dr. C. C. Apams, devoted all its time (about six weeks) to Isle Royale, and the resulting report is incorporated in a volume of more than 400 pages (4). The botani- cal work was done by Hott (33), whose report comprises a tén- page.account of the plant societies, and an annotated list of lichens, mosses, ferns, and seed plants, including 364 species. There is also much of ecological value to be found in the sections by ADAMS, and the report by GLEASON upon the ecology of the invertebrates (29). Two papers by the present writer (12, 12@) should also be men- tioned, as they were suggested by observations upon Isle Royale. TOPOGRAPHY AND PHYSIOGRAPHIC HISTORY Isle Royale is situated in the northwestern part of Lake Superior in lat. 48° N., long. 89° W., about 25 km. distant from Thunder Cape, which is the nearest point of the Canadian mainland. The island is elongated, extending northeast and southwest, and its dimensions are 72 km. by 14 km. at the widest part. It is formed of several parallel ridges which are made by the resistant centers of successive outcrops of a series of Keweenawan lava flows. These dip southeastward at angles varying from 5° to 40°. The southeast slopes of the ridges are gentle, corresponding with the dip of the beds, while the northwest faces are steep and broken, often pre- cipitous. Several of them extend into the lake at either end of the island as promontories or rows of small islands (fig..1). The largest, the Greenstone Range, stretches the whole length of the island, and is continued northeastward in Passage Island and Gull Rocks. At several points it reaches an altitude of more than 150 m. above the lake level. Between the ridges are narrow valleys, corresponding with the less resistant peripheral portions of the flows and the sedimentary layers that are interbedded with them. These contain many lakes, and where submerged at the ends of the island form narrow fiord-like harbors and channels. The drainage is well adjusted to structure, the streams flowing along the strike 1913] COOPER—ISLE ROYALE 5 of the less resistant beds, entering the lake at the ends of the valleys, or occasionally through narrow cross valleys, most of which are due to faults. The quaternary history of Isle Royale is briefly as follows: At the beginning of the glacial period the topography, produced during a long period of subaerial erosion, was essentially as now. The ice completely covered the island, moving southwestward nearly with the strike of the beds, but wrought only slight modi- fications in the topography. Rock basins were excavated in the .—Southeast across Scovill Point and the outer islands from the slope of the Fic. 1 Greenstone Range: Tobin’s Harbor in the foreground; Rock Harbor beyond; Lake Superior in the distance. valleys and many surfaces were smoothed and striated. Roches moutonnées are common. Of the little drift that was left behind most was dropped upon the southwest end, and practically all has been rehandled by the waters of the successive postglacial lakes. Upon the retreat of the ice, Isle Royale was left entirely sub- merged beneath the waters of Lake Duluth. The remaining history records a gradual emergence corresponding with the repeated changes of the water level as the lake found successively lower outlets. That this emergence was frequently interrupted is shown by the beaches, sea clifis, and wave-cut terraces that occur at various altitudes, corresponding with similar ones along the 6 BOTANICAL GAZETTE [JANUARY mainland coast. These indicate periods when the water level was stationary for a considerable time. According to LANE (36) the present shore line is more strongly marked than any at higher levels. “Nor is it surprising,’ LANE remarks, “that the lake level should now be tolerably constant, for Lake Superior now drains over a rock: threshold.” In comparatively recent post- glacial time (since the formation of the very recent Nipissing beach) tilting occurred in the Lake Superior region, with uplift northward. This must have modified more or less the drainage conditions upon Isle Royale. It is important to bear in mind the self-evident fact that never since its first emergence from the waters of Lake Duluth has Isle Royale been connected with the mainland. For further geologic and physiographic details the reader is referred to LANE’s report (36), to which I am indebted for the material for this brief sketch; and also to ADAMs (4), who discusses the physiographic history of the island with considerable fulness. ApAms also gives much valuable data concerning the influence of the lake storms and surface currents upon the biota of the island. PHYSIOGRAPHIC AGENCIES NOW AT WORK The agencies that are now modifying the surface of the island, which are of course the same that have been active throughout its history, may be considered under two heads. Among the DESTRUCTIVE agencies, weathering is of the greatest importance in its influence upon vegetation. It is most evident upon the steep northwest slopes of the higher ridges. Here there are somewhat extensive talus piles lying at the bases of cliffs, or in some cases occupying the whole slope, the cliff having been buried by the accumulation of fragments. In many places the talus is fully clothed with climax forest, in others the fragments are bare or merely lichen covered. The results of weathering are evident also upon the bare rock shores, where scales and plates are seen to have been split from the rock surfaces through the agency of temperature changes. Very important, though effectually concealed, is the chemical action which is going on beneath the humus carpet that covers most of the island’s surface. Between the humus and the bed rock there is nearly everywhere a layer of 1913] COOPER—ISLE ROYALE 7 small rock fragments mixed with organic matter. Most of these fragments are so decomposed that they can be cut easily with a knife. The bed rock itself frequently shows the effect of chemi- cal action. Vegetation is here seen as an important physiographic agent. Stream erosion is of trifling importance upon Isle Royale because of the small size and low gradient of most of the streams and their freedom from transported materials, necessary as agents of abrasion. Wave erosion is the most conspicuous of destructive agencies. The surf is actively cutting into the land, and the shore features at the present lake level are very pronounced. At many points along the southeast coast the normally gentle slope of the shore has been transformed into terrace and cliff. In some parts of the abrupt northwest shore the waves are undermining the climax forest itself. In connection with erosion by waves should be mentioned the work of ice, the precise effects of which could not be determined in sum- mer study. Under the head of CONSTRUCTIVE agencies come deposition by streams, waves, currents, and vegetation. The only notable instances of stream deposition are the few deltas, the materials for which were derived largely from the glacial drift and the products — of wave erosion at former levels. The subject is treated further under the head of “‘Delta swamp succession.” The fragments eroded by waves are deposited in the form of beaches and bars, in coves and harbors. Shore currents are effective in transporting the material, and in sweeping the finest into sheltered bays, where it is dropped in the quiet waters. The work of vegetation consists in the formation of peat and humus. Plant life here again appears as a physiographic agent of great importance. CLIMATE ADAMS (4, pp. 41-44) has described in some detail the climate of the general region, his data being obtained from the records of the Weather Bureau at Port Arthur. . The following summary (table I) is derived partly from ApAms’ account and partly from more recent data from Port Arthur obtained through the courtesy of the Canadian Weather Service. 8 BOTANICAL GAZETTE [JANUARY TABLE I NORMAL TEMPERATURE AT PorT ARTHUR FOR THE 20 YEARS 1888-1907 | Jan. | Feb. | March {Apri May | June | July | Aug. | Sept.) Oct. | Nov. | Dec. | Yr. PC. ste Oats 778 r.7| 7.7|13-6|16.8|x5 .6]11.6) 5.3|—2-8 —9.8 2.1 The average maximum temperature for the ten years 1896- 1905 was 30.1° C.; the average minimum for the same period was —34.9°C. The mean monthly temperature was below o° C. for five months, and the mean monthly minimum below o° C. every month except June, July, and August. The growing season is thus short, including about four months, or even less, between the middle of May and the middle of September. The long northern period of daylight compensates somewhat for the short season. TABLE II NORMAL PRECIPITATION AT PorT ARTHUR FOR THE 20 YEARS 1888-1907 Year | yan. Feb. May July | Aug. | Sept. Oct. | Nov. | Dec. act Bada romdeges Peewee |t-77|t-31|2.44|4.18)5..56|7-67\9.82|7.7/8.23/6.49|3.15|t.77|60.16 Mar. |April June It is here seen that the greater part of the precipitation takes place during the growing season; 39.05 cm., or more than three- fifths of the total, occurs during the months May-September. The snowfall is rather light; during the six years 1900-1905 the average was 61.03 cm. Reduced to water this amounts to a precipitation of 6.1 cm., which is about one-tenth of the average total for that period. The evaporation rate is doubtless low because of the low temperature, but there are no data available. This and the rela- tively abundant precipitation during the growing season seem adequate to account for the extreme mesophytism of the forests of the region. ‘ Since 1906 temperature and precipitation records have been kept during the season of navigation by Captain MALonE at the lighthouse on Menagerie Island. This is one of the Isle Royale archipelago situated 4 km. distant from the nearest point of the main island. During the summer of 1910 I kept thermograph and rain gauge records at Park Place. There is therefore opportunity 1913] COOPER—ISLE ROYALE 9 for a partial comparison of the insular climate with that of the mainland. Summarization of the records for Port Arthur, Park Place, and Menagerie Island gives the following results: TABLE III TEMPERATURES ° C. June July August Put Arh Mean maximum 23.4 23.9 21.3 Mean minimum 10.4 Ce ee 10.0 Mean daily range 13.0 12.2 ax-4 Park Places oo Mean maximum ae S14 S14 minimum pare $254. 12.9 Mean daily range ee 9.0 8.5 Menagerie Island............ Mean maximum 17.0 18-8 19.4 M inimum Hie 10.5 23:5 Mean daily range 9.9 8.3 6.3 From this table we see that the maxima upon Isle Royale are lower than upon the mainland, during the summer at least. Menagerie Island, most under the lake’s influence, is the lowest, and Park Place, upon the main island, is intermediate. We may infer that as a result of lower temperatures the evaporation is less upon Isle Royale. Apams (4, p. 44) suggests that insular location and imperfect drainage probably operate to reduce evaporation. The table also shows that the Isle Royale climate is characterized by less pronounced daily temperature changes than is that of the mainland. The daily range is shown to be uniformly greatest at Port Arthur, intermediate at Park Place, and least at Menagerie Island. A further comparison (table IV) brings out the fact that the proximity of the lake retards the opening of the growing season, but also that the same factor prolongs it into the fall. : TABLE IV MEAN MONTHLY TEMPERATURES (° C.) May-Nov.; AVERAGE 1906-1909 May June July | August} Sept. Oct. Nov. PORt ATU oe i 4s 6 1 10.8) £8.05) 41.6 1.28.7 ie. Menagene Isiang.. 2.22... A:3 1 8.0 1 11.6 | 34.8 1.52:5 |. 6.8) 3.0 Io BOTANICAL GAZETTE [JANUARY Evidencing the retardation of the season is the fact that ice frequently remains in sheltered places on the northwest coast of the island into July. I have seen a deserted mine shaft filled solid with ice on July 4. Foster and WHITNEY report ice ‘under the shade of crags, and among the thick evergreen swamps of white « cedar.” In precipitation there is apparently not -much difference between Port Arthur and Isle Royale, at least during the growing season. As far as the records go the mainland has a slight advantage. TABLE V AVERAGE PRECIPITATION May-—Nov., 1906-1909 eee Eb ee ee es oa eS 48.00 cm. Peeeree SAIN os ss ee Se ee 43.74 cm. From the foregoing data, which unfortunately are rather frag- mentary, it appears that there is at present no ground for concluding that the island climate is effective in producing a more mesophytic type of vegetation than that of the mainland, or vice versa. The lower evaporation rate upon the island, due to lower temperature, is balanced by a less precipitation during the growing season; and the growing season, although retarded in its commencement upon the island, is apparently as long as upon the mainland. The question cannot fully be settled without fuller precipitation records from Isle Royale and a determination of the actual evaporation rates in the two localities. The data presented, however, indicate, so far as they go, that the insular position of the field of study does not seriously affect its value as a fair sample of the region dominated by the northeastern conifer forest. Part I.—The climax forest The forest that completely clothes the surface of Isle Royale, with the exception of a part of the bog areas, some limited stretches of xerophytic character, and the small portion dominated by the maple, is made up largely of three trees: Abies balsamea (L.) Mill (balsam fir), Betula alba L. var. papyrifera (Marsh) Spach (paper birch), and Picea canadensis (Mill) BSP (white spruce). The studies embodied in the present paper show that this type is the 1913] COOPER—ISLE ROYALE II climax forest of that portion of the northeastern conifer region under consideration; in other words, that upon Isle Royale it is the final and permanent vegetational stage, toward the establish- ment of which all the other plant societies are successive steps. It is the “climatic” forest of the region, permanent while the climate remains essentially as now. The evidence in support of this conclusion lies along four lines: (1) extreme mesophytism of the forest; (2) its uniformity of development; (3) all successions lead to it; (4) maintenance of equilibrium. These lines of evidence will now be considered in order. 1. Mesopuytism.—The balsam-birch-white spruce forest is the most mesophytic of all the plant societies of the island. The truth of this statement will appear during the discussion of other points and so no further treatment is necessary here. 2. UNIFORMITY OF DEVELOPMENT.—In all places where it occurs, whether upon rock surfaces or reclaimed bogs, upon the part most recently emerged from the lake or upon the highest ridge, the dominant forest is essentially uniform in character. The tree species are the same, and they bear everywhere the same relations to each other. 3. ALL SUCCESSIONS LEAD TO THE BALSAM-BIRCH-WHITE SPRUCE FOREST.—In a later portion of this paper the various successions are treated in detail, and it is shown that all end with the establish- ment of the balsam-birch-white spruce forest. In other words, those phases of the vegetation that are not uniform in character with the main forest mass are plainly tending toward uniformity. The successions upon Isle Royale may be classified as follows: A. Primary successions I. Xerarch* successions 1. The rock shore succession 2. The beach succession * The terms xerarch and hydrarch are here used for the first time, for the purpose of indicating a natural and important classification of plant successions. The former is applied to those successions which, having their origin in xerophytic habitats, such as rock shores, beaches, and cliffs, become more and more mesophytic in their succes- sive stages; the latter to those which, originating in hydrophytic habitats such as lakes and ponds, also progress toward mesophytism 12/ BOTANICAL GAZETTE [JANUARY II. Hydrarch successions 1. The bog succession 2. The delta swamp succession B. Secondary succession The burn succession 4. MAINTENANCE OF EQUILIBRIUM.—It has been possible to state with brevity the three points that have so far been presented; indeed, to one visiting the island they are almost self-evident. The validity of the fourth is not so plainly to be seen. Both observational and experimental studies have shown that the balsam-birch-white spruce forest, in spite of appearances to the contrary, is, taken as a whole, in equilibrium; that no changes of a successional nature are taking place within it. Superficial observation would be likely to lead to exactly the opposite conclu- sion. In the presence of the other good evidences of permanence outlined in the preceding paragraphs, it became necessary to seek for an explanation of the seeming condition of rapid change that was apparently so plain in the forest. The solution was found in the course of a detailed study which included (1) the characteristics and life history of each tree species and of certain of the lower forms which were of importance, and (2) all the processes and changes brought about through the interrelations of the forest species, discovered by intensive study of a number of limited areas of definite size (quadrats), with every available source of evidence laid under contribution; in other words, an attempt at a thorough investigation of the dynamics of the forest. In the following dis- cussion the results will be given under three heads: I. Description of the forest; II. Studies of individual species; III. Quadrat studies. I. DESCRIPTION OF THE FOREST For the sake of concreteness I have selected a definite locality for description, bearing in mind, however, that such a thing as a piece of forest of limited extent which is “typical” of the growth of a region hardly exists. Smithwick Island (sec. 4, T. 66 N., R. 33 W.) was the selection for this description and for particular study, because the outer row of small islands inclosing Rock Harbor had the appearance of a i al ata a Pee ee Oo ae ; \ ; t ROP ee ee ne ee Be ee, ee Mie esr EL 7) eS a a le Eee aes eS ey Ne Te ey tS Fp, SES = ae tal Re ee ee er 1913] COOPER—ISLE ROYALE 13 having been least disturbed by accidental conditions such as fires; and of these islands Smithwick was the most iently situated. So primeval and luxuriant is the aspect of the forest here that at first it seemed almost safe to assume that the island had never been burned over since its emergence from the lake. [I found, however, in one place, at a depth of one-third of a meter, a layer of carbona- ceous material with fragments of charcoal. It is certain then that fire, to an unknown extent, has entered into the history of the island, notwithstanding the many indications to the contrary. Nevertheless, granting that the island may have been burned over at some time, it is plain that the forest has long since returned to its natural condition and may fairly be taken as a suitable area for the study of the climax state. We may be sure that the forest on Smithwick Island has not been disturbed for many hundreds of years at least, and this is not often the case on ‘the main Isle Royale. There is one somewhat abnormal feature of the conditions surrounding these outer islands that should be mentioned, namely, that the exposure to the strong lake winds is greater than on the main island, and that the death-rate among the trees is thereby increased, and not always proportionally among the different species. On the whole, though, this added exposure merely inten- sifies certain processes that are in operation everywhere, and thus renders them easier of observation. ‘The average elevation of Smithwick Island is about 7m. The southwest one-third was thoroughly burned over about 15 years ago. The forest covers the unburned portion almost completely, being bordered along most of the Rock Harbor side by a narrow shingle beach, and on the lakeward edge by a belt of bare sloping rocks, frequently interrupted by broken or precipitous sea cliffs. Seen from Rock Harbor the forest has the following appearance, and this description will apply fairly well to the climax forest of Isle Royale in general (fig. 2). The first impression is of great density, the thick foliage extending to the ground at the edge of the forest, allowing no view into the interior. The sky line is ragged, made up of an irregular combination of sharp points and rounded curves, due to the mixture of broad-leaved trees and conifers. 14 BOTANICAL GAZETTE [JANUARY Above the general level of the treetops tower occasional very old white spruces, conspicuous features in spite of or rather on account of their fewness. The paper birches make considerable show by reason of their thick tops, often appearing to compose at least half of the forest, but in reality not much more abundant than the spruces. The balsams are plainly very abundant, and are actually even more so than they seem, since many small ones are hidden by other trees. There are a few large specimens approaching the spruces in size, and thick groves of medium-sized trees are just Fic. 2.—Exterior view of the climax forest upon one of the row of islands bound- ing Rock Harbor on the southeast: two tall white spruces at the right; a group of balsams at the left; several large birches. visible, their spirelike tips appearing in dense clusters among the birch tops. The forest toward the harbor is bordered by a belt where Alnus crispa (Ait.) Pursh (green alder) is common, filling in the gaps between the trees. In this region Pyrus americana (Marsh) DC (mountain ash) is also frequent, and Thuja occidentalis L. (arbor vitae) is occasional. Upon entering the forest we seem in many slice to be in the midst of a dense growth of nearly pure balsam. The individuals of this species are of all sizes, and there is a pronounced tendency among them to grow in close groups. The small trees (roughly 1913] COOPER—ISLE ROYALE 15 those 7 m. high and under) are greatly in excess of the larger ones. There are also numerous dead and dying specimens, almost always small ones, some of the dead trees showing evidence of having suc- cumbed very recently, the needles not yet having dropped off. The occasional large trunks of the birches are conspicuous objects, but young ones are not numerous. It is often difficult to find a single spruce, unless one has carefully estimated from the exterior the position of one of the conspicuous old specimens. Young spruces are exceedingly rare, so that a long search will be necessary to discover one. The shade in most parts, espe- cially under the closely placed balsams, is dense, though there are frequent partial openings, caused principally by windfalls (fig. 3). Standing dead trees of large size are very rare, but fallen trunks in all stages of de- composition are numerous, the greater number being balsams, though the dead birches are more conspicuous on account of their greater size. 5 : Shrubby growth is not Fic. 3.—Illustrates conditions result- abundant. Theareasof not too ing from a windfall in the climax forest: dense shade are. often thickly fallen trunks and young balsams; Smith- ‘ wick Island. populated with Taxus canadensis Marsh (ground hemlock). Other large shrubs that are more or less frequent are Alnus crispa (Ait.) Pursh (green alder), Viburnum pauciflorum Raf. (high bush cranberry), Sambucus racemosa L. (red-berried elder), Lonicera canadensis Marsh (bush honeysuckle), Fatsia horrida (Sm.) B. & H. (devil’s club), the last abundant in one restricted area. The herbaceous growth is sparse except in partial openings. 16 BOTANICAL GAZETTE [JANUARY Most prominent is the association of about eight herbs which is so characteristic of the northeastern conifer forest, and in part of similat forests over a much wider range. The group includes the following: Cornus canadensis L. (bunch-berry), Trientalis americana (Pers.) Pursh (star-flower), Linnaea borealis L. var. americana (Forbes) Rehder (twin-flower), Maianthemum canadense Dest. (two-leaved Solomon’s seal), Clintonia borealis (Ait.) Raf., Miiella nuda L. (mitrewort), Aralia nudicaulis L. (wild sarsaparilla), Coptis trifolia (L.) Salisb. (goldthread). These species are found in every part of the Isle Royale climax forest, and many of them in the bog forest, bogs, and along the rock shores as well. Others, less characteristic and abundant, still occur commonly: Lyco- podium annotinum L. (stiff club moss), L. obscurum L. (ground pine), Phegopteris Dryopteris (L.) Fée (oak fern), Aspidium spinulosum (O. F. Miiller) Sw. (shield fern), Polypodium vulgare L. (polypod), - Cystopteris fragilis (L.) Bernh. (fragile fern), Moneses uniflora (L.) Gray (one-flowered Pyrola), Ribes prostratum L’Her (fetid currant), Epipactis repens (L.) Crantz var. ophioides (Fernald) A. A. Eaton (rattlesnake plantain), Oxalis Acetosella L. (wood sorrel), Habenaria obtusata (Pursh) Richards, Comandra livida Richards. By far the most important part of the herbaceous vegetation, both quantitatively and ecologically, is the moss contingent. This forms a nearly continuous carpet, being absent only where the shade is very dense. Three species are chiefly concerned, and these are quite equally distributed, one usually being dominant in a given spot. Calliergon Schreberi (Willd.) Grout (Hypnum Schreberi Willd.) is perhaps the most abundant, and grows in the drier places alone, as well as mixed with the other two in general. Hylo- comium proliferum (L.) Lindb. usually covers the areas of well decomposed humus; while Hypnum crista-castrensis L. seems to prefer rotten wood. Next to these in abundance is Hylocomium triquetrum (L.) Lindb. The humus soil, which is composed largely of moss remains, tree waste, and rotten wood, varies in depth from 0.25 to 6 dm., the average being perhaps about 3 dm. It rests directly upon the smooth rock surface or is separated from it by a loose layer of decomposed fragments. 1913] COOPER—ISLE ROYALE 17 Returning to the trees, the first conclusion would naturally be that we have here a stage in the succession approaching but not having reached the final or climax condition. The spruces and birches appear like relicts, and the balsams, which seem to be of all ages, but mostly younger than the trees of other species, are appar- ently succeeding them. The seeming probability is that before long the birches and spruces will have died out, leaving a pure growth of balsam which in the future will succeed itself. Appear- ances of this kind have sometimes been considered sufficient to prove that succession is in active progress, and there are undoubt- edly many cases where the phenomena are not deceptive. In no case, however, should the mere appearance of rapid succession be admitted as valid evidence until verified by surer methods of study. The results of an attempt to use such methods are detailed in the two following sections. II. STUDIES OF INDIVIDUAL SPECIES ABIES BALSAMEA (balsam fir).—If it be objected that the forest is after all a practically pure stand of balsam, with a mere scatter- ing of other species, the following facts will be sufficient answer. It is true that in number of individuals, all sizes considered, the balsam is greatly preponderant. Of the 254 trees included in the six quadrats soon to be described, 78.7 per cent are balsam. But if we take account only of those trees which may be considered as forming the mature stand, the percentage of balsam becomes much smaller. Size, not age, is here the proper criterion. Considering those trees which are 1.25 dm. and more in diameter, which is a rather low limit to set, the proportion is only 56.7 percent. Among the larger trees the balsams are still less numerous, making only 33-3 per cent of those 2.5 dm. and more in diameter (fig. 4). The same facts are shown when age is considered instead of size, though in a somewhat less striking manner (fig. 5). Two causes are responsible for the preponderance of balsam in the young growth. First, the seedlings make a successful start in almost any sort of situation, provided sufficient light be available. Very young seedlings were seen commonly in such diverse situa- tions as the following: natural openings in the forest caused by 18 windfall, in moss and humus (by far the commonest situation); BOTANICAL GAZETTE [JANUARY windfall opening in cedar swamp, in moss; rotten logs in forest Over 1.25dm. Over isdm Total: in diameter in diameter 254 trees. tree Lari EN va Seiasa $A Yaricina x” TS as eee ae 5.) BR Sees 5.57% Picea tee ¥ . oe marian f - 4.77% Pg 7. 57, nn oxen za Po ulu OS Eat f ES a oS 5.57 Prremuloides / | nek [ts | Pyrus (2. Gana: qo _ americana “1 jo.67 ig 6% 16.77, Pice J ie canadensis __/ é Betula alba : oe papyrifera staid Be ie Se balsamea hg ee ~ ‘ N \ Pie ‘\ \ 39% \ a Lt \ < \ ‘A ‘ ‘ ‘J 56.7% 1 \ ‘ \ 1 ‘ ‘, \ i ‘ ‘ \ 7 \ S337 Fic. 4.—Composition of the climax forest; according to size of trees (infrequent in this region); open bogs in sphagnum; crevices and humus-filled depressions on rock shores; - burned areas, both forested and bare, not abundant; upper beach among large shingle, r913] COOPER—ISLE ROYALE 19 in partial shade and entirely open, abundant in one locality; sand bar across mouth of small stream, abundant The entire absence Total: Over 30 yrs: Overeoyrs: Over ioo yrs 254 trees, 171 trees 63 trees. iz trees. Larix \e = ~4 1.6%] --- 7 laricina gh | 24d = | 3.57 a 1.6% pena? 16.6%, Pirea se en Ue oo Sues mariana //| 47% T3 e ar Se Popu lus f j -- mn nig tremuloides / /| 287 “it Py us” vA ER chek fe amertcana._,/ va 10.67 1 Pre! i / a conadensis_; ct ee Seer conse Betula alba 4177, papyrifera : 285% Abies oO on. ti ne oe balsamea 78.77 ee : 76% \\ x \ 1 \ \ ‘ \ \ 4 ‘ * y iQ 547% |‘ aH * _ \ , 4177 Fic. 5.—Composition of the climax forest; according to age of trees of very young seedlings wherever the shade is even moderately dense is noteworthy Later in life the young trees can endure severe shading, but for a successful start abundant light seems to 20 BOTANICAL GAZETTE [JANUARY ‘be a necessity. The possibility must be admitted that light (or rather radiant energy) is only indirectly the important factor, its influence lying in its effect upon the seed bed. Densely shaded soils upon Isle Royale are nearly everywhere more or less of the nature of peat, low in temperature, soggy with unavailable water, and probably like peat deficient in certain types of bacterial and fungal life. The obvious effects of abundant access of radiant energy would be to partially cure the sogginess of the soil and thus increase its oxygen content, and to bring about a high soil tempera- ture; both of which changes would result in greatly increased activity among the various types of soil organisms. Plans to carry out some experiments with a view toward determining the germination conditions of the balsam and other trees were frustrated by the total failure of the seed crop in 1910. A second cause, which easily accounts for a considerable viet of the young growth of balsam, is found in the habit of layering, by which that species reproduces abundantly. All the other coni- fers of Isle Royale except the pines possess the habit too, but to a much less degree. In a previous paper (12) I have described in detail the layering habit of the balsam and other conifers, and therefore a few words here will be sufficient. In the forest one frequently comes upon small groups of young balsams, composed often of about half a dozen individuals of various sizes. Upon superficial inspection these would easily pass for a cluster of seed- lings, but if the group be carefully dug up it will be found that the young trees are all connected with each other just below the surface of the ground. The group comes into existence in the following manner. One or more of the earliest branches of a young tree (which is sometimes hardly beyond the seedling stage) comes to be slightly covered with humus and litter, and produces roots. The tips then become erect, and taking on radial symmetry are trans- formed into miniature trees. By successive layering of branches as many as five generations produced in this manner may be included in a single group. Large drooping branches of mature individuals may layer in the same way, and it is not uncommon to find an old trunk surrounded by a circle of daughter trees developed from layered branches. The young shoots soon come to depend entirely 1913] COOPER—ISLE ROYALE 2r upon their own root systems for sustenance, and there is evidence that a considerable number of them become independent through the decay of the connecting branch. The habit is so common in the Isle Royale forests that a large proportion of the apparent balsam seedlings may be accounted for in this way. The preponderance of balsam in the young tree growth being accounted for, it is now necessary to explain its rapid decrease when greater size and age are considered. Several causes combine to bring this about. Abundant germination is itself a disadvantage, since it results in severe competition, much of the stand undergoing suppression and finally death. The species is very susceptible to fungus attacks and to diseases of many kinds. Rotten-hearted trees are very common. Witches’ brooms caused by a rust (Peri- dermium) are familiar objects. According to Moore and RocGErs (41), the liability to fungus attack is greater in pure stands than where trees are scattered. The common group habit of the species is therefore a disadvantage in this respect. The prevalence of heart rot, together with the natural brittleness of the wood, cause extreme liability to windfall, and broken trunks are a common sight, while uprooted balsams are rare. It is not surprising, in view of these facts, that in spite of its prolific power of germination the balsam never reaches the position of dominance in the mature stand. In a word, its high birth-rate is balanced by a high rate of mortality. BETULA ALBA var. PAPYRIFERA (paper birch).—The prominence of this species in the mature stand and in the general aspect of the forest has been noted, and also its comparative scarcity in the young growth. It is certain that the germination of the birch in this region is far from prolific. Very young seedlings were frequently seen, and in situations almost as varied as those inhabited by the balsam, but never in abundance as in the case of that tree. I quite frequently found very small seedlings in dense shade, but they were never more than five or six years old, indicating that conditions (probably light supply for photosynthesis) were not favorable for continued growth. Opportunity for successful reproduction comes usually, as in the case of the balsam, after windfalls (fig. 8). On account of its much less prolific germination the birch is far less 22 BOTANICAL GAZETTE [JANUARY abundant in such situations than the balsam. Its growth under the same conditions seems to be somewhat faster, however, and so the few birches of the windfall area, or some of them, soon overtop the balsams and cause the suppression of many of the latter, at the same time, with the aid of the balsams, temporarily preventing further reproduction of either species. Paper birch has com- paratively few and ineffective fungus enemies (DANA 18) and is not particularly susceptible to damage by wind, on account of its elastic branches and extensive though shallow root system. Even when it is broken off in severe storms, as occasionally happens, it has a means of recovery in its ability to send up vigorous sprouts from the stump. Occasional clumps of immense birch sprouts scattered through the forest are evidence of this power. The most effective obstacle to its increase is competition with the balsam in its early stages, and here its greater rate of growth gives it a slight but important advantage. On the whole it may be said with certainty that its low birth-rate is compensated by a very low mortality, and it is thus able to maintain itself in making a good proportion of the mature stand (figs. 4, 5). PICEA CANADENSIS (white spruce).—This species is ecologically much less important than the first two, occurring only sparingly in most places; but it attains a greater size than the other trees, and is one of the most conspicuous features of the forest. On account of its scarcity little could be discovered concerning its life-history upon Isle Royale. From the few seedlings that’ were _ observed it seems probable that abundant light is necessary for its successful reproduction. According to the United States Forest Service (22) it is not a prolific seed bearer, and has definite seed years, which in New England are about eight years apart. All the young trees seen were growing in situations where at least fairly abundant light was available: It seems probable therefore that the white spruce is also largely dependent upon windfalls for its suc- cessful reproduction in the virgin forest. It is able to withstand severe winds without breaking, as is shown by individuals towering conspicuously above the general forest level. It is not particularly liable to fungus injury. Birth-rate and mortality are both low, and the species is able to maintain its small proportion in the forest. SSE ee SRN ON Se eS ea ee eee ee ‘ ’ 1913] COOPER—ISLE ROYALE 23 OTHER TREES.—Pyrus americana (Marsh) DC (mountain ash), though fairly common, is of little importance ecologically, since it is very short-lived, never reaches any great size, and produces little shade. Its life history in most respects is similar to that of the birch, and it has the same habit of producing sprouts from the stump. Pinus Strobus L. (white pine) is scattered thinly through many parts of the forest, generally towering high above the other trees. Its ecological status seems to be similar to that of the white spruce. There is no indication that in recent times at least it has ever been abundant upon Isle Royale. Picea mariana (Mill) BSP, Larix laricina (DuRoi) Koch, and Populus tremuloides Michx., which are found here and there in the climax forest, will be sufh- ciently treated in connection with quadrats 5 and 6. Populus balsamifera L. also occurs sparingly. TAXUS CANADENSIS.—The most important of the lower plants of the forest—more important indeed than many of the trees—is the ground hemlock. Its influence lies in the completeness with which it occupies and shades the ground, preventing tree reproduc- tion over large areas. This effect will be noted in connection with quadrats 5 and 6, and quadrat 1 includes part of a ground hemlock area in which trees are practically absent. Taxus can endure considerable shading, but is never found in the dense shade cast by the balsam groups. Balsam in its turn is excluded from large areas by Taxus, so that the competition between these two species is exceedingly keen. Taxus spreads abundantly by under- ground stems, and in this way invades new areas of forest when conditions are favorable, at the same time dying out in the older portions of the growth, thus allowing other plants to start in such places. Ill. QUADRAT STUDIES The method of investigation whereby a knowledge of the dynam- ics of the forest was gained was as follows. A rectangular area was laid off, made up of one or more units of 5 m. square, the usual size being a quadrat of 10 m. square, or four units. In the diagram of this area the position and kind of every tree, down to the smallest seedling, was plotted and its diameter noted. Cuts were next made with an ax to the centers of the large trees, and the small 24 BOTANICAL GAZETTE [JANUARY ones were felled. The age of every tree was then determined by counting the annual rings, and note was made in each case of the degree of soundness of wood, width of rings, and periods of suppres- sion indicated thereby. The cuttings were made at the height of about o.3m. An element of error is introduced here, making» the age as determined a few years too low. It seemed inadvisable, considering the many quadrats to be studied, to use up much valuable time in making the counts absolutely accurate. This would have involved the cutting of every tree at the surface of the ground, a very difficult and slow process. A saw might have been used instead of an ax, but when the rings are at all obscure it is impossible to count them from a sawed surface. I believe that the error introduced does not affect the validity of the results, since it is approximately the same in nearly every instance. The method on the whole gave excellent results, in the study of the rock shores and bogs as well as of the climax forest. Its use was made easy by the comparatively small size of the Isle Royale trees. Sixteen quadrats were studied in all, comprising 74 units of area, and involving the determination of the ages of about goo trees. If objection be raised that the method is unduly destructive, it may be answered that the cutting over of these small areas produces exactly the same effect as does windfall, a process that is continually taking place, and thus makes possible a new crop. In addition to the statistical study of the trees, careful notes were taken of the lower vegetation and the physical factors of the habitat. Less detailed studies of many other localities were also made for comparison with the quadrats. The results of the quadrat studies so far as they concern the climax forest will now be given in detail. The first four described were located on Smithwick Island; quadrats 5 and 6 were upon the main Isle Royale. Quadrats on Smithwick Island QuaprRaT 1 (fig. 6).—This quadrat exhibits most clearly the relations which the different tree species hold to each other and to the physical conditions of the habitat. It includes but one spruce, an aged giant 250 years old, long past maturity, with sparse foliage, ee ee ee) ee ee ee ee a ete Se eae ey ae 1913] COOPER—ISLE ROYALE 25 giving practically no shade. Two healthy birches (105 and 107 years old), close together, produce considerable shade in their vicinity. There are several rather old balsams (64-90 years) well Cc = pete lee cer . RY , & A & Sie A © nanan nee (©) Ay ms as aA, Ay jaa A | A AN 4 ase: ’ \ be Seve / ess DN ETT . ANRAASS A ay ja a ASNANASS hf a Ls CNS SS a \ CARA AT a Pee SSOe NE CSN y, SNASSA SANS Fo Reo aS. ESO iat tty iia As EE SSS Fe eth H RONAN SS - 1 a Bs PASSE SSNASSEN OS o { PANN SSS NAO CS es KI SSSA W g \ / s ‘ ~~ aX 2 Nt FASS SSS SS ee i "i Ae, rN BBL PY NSE SOSSS SSS a Abies balsamea oy Dead stumps 4& Picea canadensis | Betula alba papyrifera 3 yrus americana Taxus canadensis Fic. 6.—Quadrat 1, Smithwick Island: the symbols indicate the species; the numbers within them the ages of the trees by tens; for example, a tree marked 6 is _ between 61 and 70 years of age. scattered over the quadrat, and usually more or less isolated from q the smaller growth. The young trees are practically all balsams, __ the only representatives of other species being two mountain ash 26 BOTANICAL GAZETTE [JANUARY (one a clump of three stump sprouts) and a 20-year old birch in the lower right-hand corner. The young growth is not evenly dis- tributed, but shows a tendency toward grouping, which tendency will be seen in each of the succeeding quadrats. The larger number of trees of each group are approximately even-aged. For example, the rather scattered group a that surrounds the 5 balsam stumps contains 13 balsams, 10 of which are 23-28 years old. Of the 18 trees in group 0, 14 are between the ages of 30 and 50, not so uniform as the last, but decidedly of a single generation. Of the 13 trees in group ¢, all but the mountain ash and the large spruce are under 30 years. Group a illustrates in a striking manner the way in which these even-aged clusters come into existence. Within its limits were 5 large rotten balsam stumps from which the trees had been broken a meter or more above the ground. The group evidently constitutes a windfall, probably caused by a single storm, one tree in its fall carrying others with it. Such windfalls of various ages are exceed- ingly numerous throughout the forest, the balsams, on account of their brittleness and susceptibility to fungus attack, being the ones most frequently destroyed. This particular windfall is of special interest because it was possible to determine the time at which it occurred. One of the large balsams in falling pinned to the ground a young tree of the same species, which, in spite of unnatural position and dense shade caused by the branches of the fallen one, has continued to live up tothe present. The younget tree was 49 years old, and the first 12 rings were exceptionally wide, showing that up to the age of 12 years it was an unusually vigorous sapling. At this point a sudden change becomes evident, for the remaining rings are so close that in counting them a magnifying glass was an absolute necessity. This change could have been brought about only by some sudden and violent cause, and this cause is evidently to be found in the fall of the older tree. The windfall is therefore to be dated about 37 years ago. Returning to the trees composing group a, we find that they are all balsams; one is 85 years old, another 38, a third 14, and 10 range from 23 to 28; 11 then are subsequent to the windfall, and 10 began life ‘I913] COOPER—ISLE ROYALE 27 within a period of six years, 9-14 years after the windfall occurred. There is only one that clearly antedates it. Upon inquiring as to the cause of these facts, the factor of radiant energy immediately suggests itself (see p. 20). The older balsams, now fallen, when living were close enough to cast a dense shade over the area which they controlled, and there can have been no young trees beneath them, since if there had been, the present generation would antedate the windfall. It was not until 10 years after that event that young balsams began to appear in the area. Radiant energy being the principal factor involved, this interval of a number of years is entirely to be expected, since some time would elapse before the disintegration of the tangle of branches with their persistent needles would allow a large amount of the energy to reach the ground. Evidence in support of this hypothesis was found in every quadrat and in every considerable part of the forest. In no other case was it possible to determine the exact age of the windfall, but the general relation between the older and younger generation was usually plainly to be seen. Frequently the only sign of windfall is in the rotting moss-covered logs, but the close group of even-aged trees, sometimes 50 years old or more, tells the story plainly. In quadrat 1 two other windfall areas are shown, one (c) quite recent, the other (6) older. The greater range of age among the trees in these areas suggests that those of the former generation did not all fall together. This type of windfall is commoner than that represented by group a. ‘The fall of the first trees gives the wind a better chance to reach others. This slow process may be extended over a long period, even until the new generation has begun to fill in the gaps first made. In contrast to the dense group- ing just described is the remaining area of the quadrat, where the older. The part not included in the three groups comprises two- thirds of the area of the quadrat, yet it contains only 18 trees, 7 of which are over 60 years; while the other third of the quadrat con- tains 45, only 5 of them being over 60 years. The fewer trees in the larger part nevertheless produce a dense shade, and there is very little young growth beneath them. 28 BOTANICAL GAZETTE [JANUARY There is a difference that should be noted between the shade- producing capacity of the balsam and that of the birch. The former, with its many whorls of short branches close together and its opaque leaves, casts an exceedingly dense shadow which does not influence a large area. A moderately close stand of large balsams allows extremely little light to reach the ground. The birch (in its primeval forest form) influences a large area, but its shade is not dense, because of its comparatively thin crown and translucent leaves. Under the shade of large birches there is frequently a scattering of young growth, while under thrifty balsams there is rarely to be found any at all. Both conditions are well shown in the diagram of quadrat r. The effect of shading is seen also in the undergrowth. In the dense shadow of the balsams there is a mere sprinkling of herbs, and mosses are usually absent entirely, the ground being covered with a layer of tree waste. It is in shade of moderate density and in openings that the greatest luxuriance of mosses and herbs is found. The ground hemlock is excluded from most of the quadrat for the same reason, but in the lower right-hand corner there is an area completely occupied by a dense growth of it, which effectually prevents the establishment of any other species. QuApRAT 2 (fig. 7).—This quadrat shows the same features as the last. Group a contains a great number of young trees of similar age, mostly balsams, which have started as a consequence of one or more windfalls. Of the 40 balsams in the area, 33 are between the ages of 20 and 35 years, and within these limits, as shown by the diagram, there is a tendency for those of similar age to be neighbors. Numerous fallen trunks represent the former generation. The large balsam marked “12,” which was 121 years old—an unusual age for this species—was past maturity, and like the big spruce in the preceding quadrat was ineffective in producing shade. At b there is a part of an older group, 5 of the 7 balsams being between 44 and 53 years old. The upper left-hand corner is dominated by a few old and large trees, balsams and birches, with practically no young ones—only a few beneath the birches. The shade in this area was dense and the undergrowth sparse, even the ground 29 COOPER—ISLE ROYALE No spruce grew in this quadrat t913] hemlock being nearly absent but there were occasional large ones near QuADRAT 3 (fig. 8).—This small quadrat of one unit area shows a group of even-aged trees, among which are several young birch NS ven A Be Oe re “8 oN x Abies balsame Betula alba ‘papyritera Pyrus american Fic. 7.—Quadrat 2, Smithwick Island; for explanation of symbols see fig. 6 and mountain ash as well as balsam. No living trees of a former generation are present within the limits of the quadrat, but several were seen near. Decayed trunks were frequent and were mostly birch. Of the 37 trees, 26 were within the ages of 26 and 35 years imits. Evidently then all and the others were very close to these limits 30 BOTANICAL GAZETTE [JANUARY three species started growth at practically the same time, and the immediate cause was a windfall. The birches are tall and spindling, but now slightly overtop the balsams in spite of a somewhat later start. Having gained the advantage as to light supply, their tops will spread fast, and these trees, or more likely one or two of them, will doubtless finally develop the thick-stemmed, spreading, round-topped form characteristic of mature specimens in the virgin forest. The balsams which are within the sphere of influence of the birches will be suppressed. This process in fact has already begun. The last 5-10 rings of those balsams which were close to the birches were found to be noticeably narrower than the earlier ones, while the rings of those growing isolated from other trees were uni- formly spaced. Undergrowth was practically lacking, the shade being everywhere very dense. Even the ground hem- lock was entirely absent. S$ balsam z ‘ sul alba Ppapyrifere g In this quadrat the moun- as ne . ae tain ash showed an interesting a2 eke, pa ce habit of growth. Several sap- lings were seen among the clos- est groups of balsams which were so slender and weak as to closely resemble lianes. One specimen was 4.3 m. high and 2.25 cm. thick at the base, unbranched, with a single tuft of leaves at the top. It was supported entirely by the balsams against which it leaned, and its upper portion had penetrated among the interlacing balsam branches close to the trunk of a near-by tree. It was 16 years old, and had evidently started before the balsams had begun to shade the ground thoroughly, but was left behind in the severe competition for the available light supply. QuapRAT 4 (figs. 9, 10).—This quadrat, also of one unit area, includes two generations of balsam and no other species. Several large birches were near by and a large spruce. The older generation _ plainly showed recent suppression. Bees pe ee eet ee ee Nene i ae ET OE Rae eee a 1913] COOPER—ISLE ROYALE 31 is represented by one individual in the lower right-hand corner, well isolated from other trees, 115 years old. The younger generation illustrates competition between individuals of a single species which began life at about the same time. Fig. 9 shows the age of each tree, and fig. ro its diameter, which, it may be noted, maintains a pretty constant proportion to height. It will be seen from the latter that 4 trees (marked by double symbols) have attained a much greater size than the others; and if comparison be made with fig. g it will be evident that these 4 are not noticeably older than A Bs A Ls. A A a = - A a cS A a. aN AAA A Sn bd as dA As re - Ay AA 2 By AN pp. Pn ~ wr; A as A A A A Abies balsamea A 28 10 Fics. 9, 10.—Fig. 9, ee 4, Smithwick Island: age of trees; for explanation of aba see fig. 6; fig. 10, quadrat 4, size of trees; the numbers indicate the diameters of the trees in Acchaotae their neighbors. The annual rings of these 4 trees were found in every case to be wide and evenly spaced, while those of their less favored companions were either very narrow from the beginning or This illustrates an important principle in forest study, namely, that no reliance can be placed upon the size of a tree in fixing its age or in determining its place where two or more generations are concerned. These 4 individuals in some way gained the advantage early in life and caused the suppression of their neighbors. Evidence of the severity of the shading was shown by the presence among the living balsams of 20 dead specimens, averaging a meter in height, and in length of 32 BOTANICAL GAZETTE [JANUARY life from 14 to 38 years. Some had been dead for a long time, while others showed evidence, in needles still clinging, of having been alive until very recently. All had undergone severe suppression. In consequence of the deep shade the undergrowth was extremely sparse, except in the lower left-hand corner where there was a partial opening. Here was a luxuriant growth of mosses, including Hylocomium proliferum (dominant), Hypnum crista-castrensis, Calliergon Schreberit, and Dicranum undulatum. The close group of young balsams occupying this locality was largely due to layering. Quadrat 4 then includes in the main a group of balsams of very different sizes, giving an appearance of gradual reproduction, but in reality essentially even-aged, and belonging distinctly to a single generation. Quadrats on the main Isle Royale It has been said that the conditions on Smithwick Island include one that is somewhat abnormal for the region as a whole, namely, that the exposure to wind is greater. Two quadrats in sheltered localities on the mainland of Isle Royale were studied for the purpose of comparison. They probably represent the opposite _ extreme so far as exposure is concerned. QuaADRAT 5 (figs. 11, 12) was located a few hundred meters back from the southeast shore of the Blake Point peninsula in sec. 23, T. 67 N., R. 33 W. The locality is thoroughly sheltered from northwest vind by the main ridge, and from the lake winds by the islands to the southeast. On the diagram several points of difference from the preceding quadrats are readily seen. Most noticeable are the greater average age of all species and the absence of very young growth. Two new trees appear: Picea mariana (Mill) BSP (black spruce) and Larix laricina (DuRoi) Koch (tamarack), each species being represented by one individual. The whole stand is remarkably even-aged, 22 of the 38 trees being between the ages of 82 and 98 years. There is some tendency toward grouping of trees of similar age, though not so noticeably as on Smithwick Island. The group a is a very marked one, however. Of the 9g individuals of 4 species composing it, 7 are between 83 and 92 years, and 5 between 89 and 92. The effect of Sa SL a ai 1913] COOPER—ISLE ROYALE 33 shelter from wind is very evident in the greater height of the trees. The protection which this area enjoys does not by any means prevent windfall, but merely lessens its intensity, and allows the trees to reach a greater height before they are overthrown. Several @ Se! ea - - of | - -- > <| oPe bak weer symbols see fig. 6. Abi ies balsamea 8 zt Betula Sioa. sities 1 ; maria Leer ik (aricina. 1 Fic. 11.—Quadrat 5, Blake Point Peninsula: age of trees; for explanation of standing dead balsams were seen on this quadrat and they were frequent through the neighboring forest. On the outer islands the balsams almost never die a standing death. Quadrat 5 (fig. 12) also shows suppression of part of the stand, the larger trees being 34 BOTANICAL GAZETTE [JANUARY indicated by double symbols. The absence of very young growth _is explained by the fact that the forest floor was covered by a thick mass of ground hemlock. ' Black spruce and tamarack are found occasionally throughout the forest. Since they are both very intolerant of shade, they probably make a successful start only where an extensive windfall © : @ a ee A © © VAN gs a &“S 6 VW - A @ aN ® © © a © ees 2 Ls Oo Fic. 12.—Quadrat 5: size of trees; for explanation of symbols see fig. 10 has let in abundant light. The black spruce as a member of the upland forest is abundant in one locality on the southeast shore of Isle Royale and in certain other places. The evidence seems tO show that this species in abundance in the upland forest indicates a transitional stage approaching the climax. The subject will be treated again in the consideration of the rock shore succession. : 4 1913] COOPER—ISLE ROYALE 35 QuapRAT 6 (fig. 13).—The conditions here as to shelter were similar to those of the last. The quadrat was located near the shore of Tobin’s Harbor in sec. 33, T. 67 N., R. 33 W. The small number and large size of the trees are noticeable, and also the entire a) ZAIN VEN rad a LV © ples pecan Bite i 4 Pic Vv 0 anade 1 Stula alba Papyritera I yruS americana vA Populus tremuloides 6 Fic. 13.—Quadrat 6, near Tobin’s Harbor; for explanation of symbols see fig. 6 absence of young growth, in spite of the comparative lightness of the shade. These conditions were plainly due to the mat of ground hemlock which practically covered the quadrat. The ground hemlock therefore, rather than any tree species, dominates and 36 BOTANICAL GAZETTE [JANUARY controls this area. The surrounding forest. was found to be essentially similar to the sample, except that the cover of ground hemlock was not continuous, and where it was absent the usual conditions of windfall reproduction, especially of balsam, prevailed. The large number of good-sized trees, balsams being specially noticeable, owe their continued existence to the protected position of the area. The presence of Populus tremuloides Michx. (aspen) in considerable abundance is noteworthy. This species seems to | be ecologically equivalent to the birch, except that it does not to any great extent possess the power of sprouting from the stump, at least in this region. A similar situation was noted in a narrow valley near Duncan Bay (sec. 28, T. 67 N., R. 33 W.), which was protected by abrupt ridges on both sides. Here the trees of all species are very large, the shade is not dense, and windfalls are relatively scarce. Groun hemlock is exceedingly abundant and large, and is plainly respon- sible for the lack of young tree growth and the resulting openness of the forest. Some scattered groups of small balsams were plainly related to windfalls. The foregoing studies show that the climax forest is a complex of windfall areas of differing ages, the youngest made up of dense clumps of small trees, and the oldest containing a few mature trees with little or no young growth beneath, those of a single group being approximately even-aged. This mosaic or patchwork changes continually in a manner that may almost be called kaleido- scopic when long periods of time are considered. The forest as 4 whole, however, remains the same, the changes in various parts balancing each other. EXTENT OF THIS TYPE OF FOREST AS THE CLIMAX OUTSIDE OF ISLE ROYALE Attempts to obtain information relating to the nature of the climax forest of other portions of the northeastern conifer region have not been attended with much success. The distributions of the various trees have been determined by Bett (8) and others with considerable accuracy, but practically nothing of an ecological nature has been published. From the data I have been able to i : ‘ OS eS ON en ee Se Sa ae age ace Re re lee TY ore feet SR 1913] COOPER—ISLE ROYALE 37 discover, the impression has been gained that the same association of balsam, paper birch, and white spruce, which is the dominant forest type of Isle Royale, is found in the most mesophytic habitats throughout northeastern Canada. The probability is that it is the climax type over much of the region, though there is not suffi- cient evidence to justify a confident statement to that effect. It is not necessary that the component species bear the same relations to each other in all parts of the region, or even that the species themselves be everywhere the same. One or even two of the climax trees may be lacking in certain places, species that are ecologically equivalent may be substituted, or others added. Analogous differ- ences occur in the deciduous forest. The two climax trees that are almost omnipresent are the maple and the beech, and yet there is a belt along the northern edge of the region where the maple alone forms the climax forest, unless the yellow birch (Betula lutea) may possibly take the place of the beech. Again, in the Great Lakes region a third climax tree, the hemlock (Thuja canadensis) is present; and in the southern Appalachians the number of species composing the climax forest reaches a dozen or more. Similarly, in northeastern Canada the climax forest may vary from place to place. Of northern Quebec Macoun (39) says: ‘In the country around Lake Mistassini it [balsam] grows mixed with aspen, birch, and white spruce, and on the lower part of the Rupert River it is found growing with the same trees all the way to James Bay.” The correspondence of this to the Isle Royale forest is striking. In reports of the Department of Lands and Forests of Quebec (45, 46) expressions such as the following are frequent, the region described being the country north of Lake St. John, west to Lake Abitibi: “well timbered, mostly with spruce, fir, and white birch, with some scattered white and Banksian pine on the high ridges.” In the “Report of the survey and exploration of northern Ontario” (43) there is much detailed information concerning the distribution of the trees in that region, though the data presented have little ecological value. However, in reading the reports of the various parties one frequently comes upon such statements as the following: “chiefly small poplar [Populus tremuloides|, spruce, white birch, 38 _ BOTANICAL GAZETTE [JANUARY and balsam, and a few balm of Gilead [Populus balsamifera|’’; “spruce, balm of Gilead, poplar, balsam, and white birch’’; ‘“‘white birch, balsam, and a few large spruce”; ‘‘the white variety of spruce of good size was seen continually along the rivers and on Picea canadensis\, Q y g wb v pa SEAS OT ENG \ DES CL Tg a LZZ2aovgre Dy =a ter sacch a i Pet, sacchaqyve' _ a gus gra SG wd | oT at a I Sar D 2 mS a Za | Reet. TE OO Tt a <4 L—} WI WA Mn ( > 4 e Fic. 14.—Ranges of the climax trees of the northeastern conifer forest and the eastern deciduous forest. ridges back from them. Black spruce, generally scrubby, clothes the muskegs..... Birch and balsam are also common on high lands.” The black and white spruces are not usually distinguished in these reports, but it is clear that the former is the principal tree upon the extensive muskeg lands, while the latter is confined to the Op Se er Pe Se pe ee en mee ee atk. eS ok a ao A ee eee ee Oe Se OT ee ee as aie ees 1913] COOPER—ISLE ROYALE 39 higher grounds, where it ams has the balsam and birch as its companions. The data here presented, though very unsatisfactory, are sufficient in my opinion to establish the probability of the generali- zation that the climax type of the whole of the northeastern conifer region is of the general character described for Isle Royale, with local variations due to the elimination or addition of species, or to the substitution of others that are ecological equivalents. Important confirmation has recently been received from Dr. ROBERT BELL of Ottawa, the best authority upon the distribution of Canadian trees, who writes: ‘‘The same type of upland forest which you describe on Isle Royale extends from the Great Lakes to James Bay and east and west of it, with modifications in parts.” On the map (fig. 14) the area shaded with oblique lines repre- sents the region over which the ranges of the balsam, paper birch, and white spruce overlap, north of the range of the sugar maple (data largely from TRANSEAU 55). It is in this region that the type of forest described is thought to be the climax. Beyond the limits of the balsam, which has the narrowest range of the three, some other species must be substituted for it, or else the climax _ forest is composed of the remaining two species alone. COMPARISON WITH THE CONIFER FOREST OF THE SOUTHERN APPA- LACHIAN SUMMITS In connection with the study of the Isle Royale forest it will be worth while to make comparison with another region that has come under my observation, where the forest is extremely similar to that described in the present paper. On the highest summits of the mountains of North Carolina, eastern Tennessee, and south- western Virginia, there are isolated areas of dominantly coniferous forest, which seem like detached portions of the great northeastern forest (see detailed description by HARSHBERGER 32). The species are different, the balsam being Abies Fraseri (Pursh) Poir., _ the spruce Picea rubra (DuRoi) Dietr., and the birch Betula lutea Michx. f. In general aspect this forest’is surprisingly like that of Isle Royale. Because of the predominance of the first tree men- tioned many of the mountains themselves are locally called “Bal- 40 BOTANICAL GAZETTE [JANUARY sams.” The results of studies upon three of these summits in western North Carolina may be briefly summarized as follows, the localities being Richland Balsam, Plott Balsam, and the Black Mountains (Mount Mitchell). The coniferous forest covers the mountain slopes from about 1600 m. to the summits, the highest of which is about 2010 m. Abies Fraseri is on the whole the most abundant species except along the lower edge of the coniferous region, where Picea rubra is of somewhat greater importance. Betula lutea is scattered more or less thickly throughout and grows to a great size, specimens having been noted that were 1.3m. in diameter. As on Isle Royale, birch and spruce are sparsely represented in the young growth, which is predominantly balsam. The shrubby vegetation consists almost entirely of Rhododendron catawbiense Michx., whic is very abundant. It is interesting to note that the balsam seed- lings are practically absent under the shade of the rhododendrons, and scarce in shade in general, but are exceedingly abundant in partial openings. The ground is covered by a luxuriant moss carpet, almost identical in composition with that of the Isle Royale forest, and the herbaceous growth includes most of the character- istic group of northern forest plants which has been listed (p. 16). The similarity between Isle Royale and the North Carolina “Balsams” is thus a striking one. In the latter region there is even an ecological equivalent to the ground hemlock. Rhododen- dron catawbiense, in spite of its very different habit, is equally effective in densely occupying and shading the ground and thus in temporarily preventing reproduction of the forest trees over wide areas. I believe that the conclusions which have been reached concerning the Isle Royale forest will also hold, with minor modi- fications, for the forests of the North Carolina summits. The conifer-birch forest of the mountains is to be regarded as the climax type of its own limited area (not including, of course, the lower slopes dominated by deciduous trees), and at the same time as an extension or outlier of the northeastern climax forest. a ae oe ee ns ag ny Cee ea eee Lem eek eae ee Se = aeee Se ae ae ES OR, Fee Pee ed re ak ee Te eee Pee 1913] COOPER—ISLE ROYALE 41 THE MAPLE FOREST OF ISLE ROYALE AND ITS RELATIONS Wherever the sugar maple occurs it forms a part of the climax forest, and is usually the dominant species therein. Between the two great eastern forest regions there is a transitional belt several hundred kilometers wide where the three climax trees of the conifer, and the two of the deciduous forest all occur (see map, fig. 14). This belt extends from northern Wisconsin through the upper peninsula and the northern part of the southern peninsula of Michi- gan and eastward to New Brunswick. WHITFORD (59) studied the successions in a portion of this belt, and found that the climax forest in northern Michigan (both peninsulas) is the beech-maple type. The balsam, birch, and spruce are very abundant, but here they belong to preliminary stages in the successions. GANONG (26, 27) gives an excellent summary of the plant formations of New Brunswick. He states that the climatic forest type is the “mixed maple-birch-spruce-fir association.” There is no indica- tion in his paper that the maple ever supersedes the other trees, but the presence of such a possibility must be admitted. The con- clusion from the studies of WHITFORD and others seems to be that the maple and beech, where not climatically excluded, are able to supersede the climax trees of the northeastern forest. Coming now to Isle Royale, we find upon the southwestern end, occupying the summit of the highest ridge, a mixed growth of Acer saccharum Marsh (sugar maple), Betula lutea Michx. f. (yellow birch), and B. lenta L. (sweet birch); with the characteristically northern trees as a minor element (see ADAMS 4, pp. 30-31, and HOLT 33, p. 224). The maple is decidedly the dominant species and reaches a large size.‘ At the northern edge of this northernmost outpost of the maples we may draw the line that separates the true northern forest from the transitional belt (fig. 14). South of this line the representatives of the southeastern deciduous forest, though not necessarily forming the bulk of the stand, yet have the upper hand; north of it the supremacy of the conifers and the paper birch is oes Pa yor eg es oe sl s% 7 n on the southern side of Michipi- coten Island, near the eastern shore of Lake Superior. 42 BOTANICAL GAZETTE [JANUARY Since glacial times there has been a continual northward advance of the forest, with the conifers as the pioneers, closely followed by the hardwoods. The problem as to whether the extension of the latter is still going on might be studied to good advantage in such localities as the southwestern end of Isle Royale, and Michipicoten Island. The large size and thriftiness of the maple at its northern- most limit would seem to indicate that it has not reached its climatic limit (BELL 8). The manner and causes of ‘‘climatic successions,” or the invasion of one climax forest by another, are still to be worked out. SUMMARY.—THE CLIMAX FOREST I. The dominant forest of Isle Royale is composed of Abies balsamea, Betula alba var. papyrifera, and Picea canadensis, with a few other species occasionally present. Abies, all sizes and ages considered, is by far the most abundant, but the greater number of individuals are small. Betula, although conspicuous, is not abun- dant, and young trees are scarce. Picea is rare, though occasional specimens tower high above the other trees. Shrubs and herba- ceous growth are sparse except in partial openings. The most important element in the latter is the moss contingent, which is responsible for the formation of great amounts of humus. II. Studies of individual species gave the following results. Abies is preponderant in the young growth because (1) the seedlings make a successful start in almost any situation provided sufficient light be available; (2) the species reproduces abundantly by layer- ing. Its rapid decrease when greater size and age are considered is due to (x) competition because of abundant germination; (2) fungus attacks, and (3) brittleness of wood, both resulting in extreme liability to windfall. Its high birth-rate is balanced by @ high rate of mortality. Betula does not germinate abundantly in the forest, but, because it is not liable to disease and windfall, holds its own with Abies. Even when broken off by severe winds it has a means of recovery in its ability to produce stump sprouts. Its more rapid growth gives it an advantage in competition with Abies. Abundant light is necessary for successful reproduction. Low ee is compensated by a very low mortality. Picea is PSPC ena A OMe eee eae ee eee oa eee Pee ed RE nS Ee tc SRE RER eae ge met up ee rep cee aA GN ane Opa ean nee OR? gk ae aie ree MPa s Se SRE R pe ee Rian Ba ea A iterse dy Se Migr Sa: sen ee a a ie igh De NM ge ee A ee dee A at tere ER Se NaS ST aaa a has 1913] COOPER—ISLE ROYALE 43 ecologically unimportant on account of its scarcity. Germination in the forest is less abundant than in the case of Betula. It is not liable to fungus attacks and withstands severe winds. Birth-rate and mortality are both low. Taxus canadensis is the most impor- tant species of the undergrowth, its influence lying in the complete- ness with which it occupies and shades the ground, preventing tree reproduction over large areas. III. Intensive study of selected areas (quadrats) yielded the following facts concerning the dynamics of the forest. The forest is a complex of windfall areas of differing ages, the youngest made up of dense clumps of small trees, and the oldest containing a few mature trees with little young growth beneath. The history of a windfall area is as follows. After the débris has disintegrated sufficiently to allow abundant light to reach the ground, a new generation of trees springs up, approximately even- aged, composed of the three dominant species, Abies always greatly preponderant. During the continued development of this group most of the individuals are at various times eliminated, A dies suffer- ing most for the causes enumerated in section II. Because of the dense shade no new individuals can start beneath them, and the final outcome is a group composed of a few large trees, approxi- mately even-aged, in which Adzes has nearly or quite lost its posi- tion of dominance to Betula. In situations sheltered from wind all species live to a greater age and windfalls are less frequent. The processes though less rapid are nevertheless the same as in more exposed situations. The result in the forest in general is a mosaic or patchwork which is in a state of continual change. The forest as a whole remains the same, the changes in various parts balancing each other. ’ IV. The following evidences that the dominant forest of Isle Royale is also the climax have been derived from the studies sum- marized above and from those dealing with the successions. 1. The dominant forest is the most mesophytic of the plant societies. 2. It is uniform upon all soils and upon areas that have passed through very different lengths of subaerial history. 3. All the successions culminate in the establishment of this as q the final stage. 44 BOTANICAL GAZETTE [JANUARY 4. The character of the forest as a whole is stable, though any given area is continually changing in composition and relative proportions of the various species. VY. The same type of forest, with local differences in some places, is probably the climax throughout the northeastern conifer region. VI. Comparison with the conifer-birch forest of the southern Appalachian summits shows a striking equivalence of species and marked correspondence between the two in ecological character- istics, indicating that the forest dynamics are essentially the same. The mountain forest may logically be considered as a southward extension or outlier of the northeastern climax forest. .VII. Acer saccharum is dominant upon the main ridge at the southwestern end of Isle Royale, reaching here its extreme northern limit in this region. Southward it is probably able to supersede the conifers and birch, while north of its northern limit the suprem- acy of the latter trees is undisputed. Pato Ato, CALIFORNIA s Sei a aes id Lake iRdalog me ae Yr i «Steamboat Td Canoe Roc SPanrel ear. ‘Sh - ~ - rec - Bare . ~ =. & Pt Se SS. = my ae Seay 2 Bau - > ISLE ROYALE Sicskewit Bay = ee Ppewa Harbor Lake Superior MICHIGAN A = BD ee Pr Houghton : cao fa Menagerie Id, DAPTED FROM ANE 6 —, “a* ais oe Sao 2s ° e le oyale iy o pee ee x mo yy, thy My Dy, ty, PROGRESSIVE AND RETROGRESSIVE CHANGES IN THE PLANT ASSOCIATIONS OF THE DELAWARE COAST LAETITIA M. Snow (WITH SIX FIGURES) During July and August 1901, certain observations were made on the plant associations of the Delaware coast, from Cape Hen- lopen southward, for about six miles.‘ Ten years later, in July 1911, the same region was again visited in order to ascertain the changes which had occurred during the interim. Considering the extreme instability of dune topography, surprisingly little change was noted, thus indicating the slowness with which plant associations, in general, change their character. Certain observations, however, seem of value, as indicating the direc- tion of change in various associations, and are therefore recorded. As in the previous study, on account of the lack of flowers and fruit, the identity of many forms was difficult—at times impos- sible—to determine. For regions which showed practically no change, no lists are presented. Where changes were noted, only dominant forms are given, in order that an idea of the direction of change may be obtained. The nomenclature of Gray’s Manual (7th edition) is used, with the Britton synonyms in parentheses. Grateful acknowledgment is due Professor Kart M. WiEGAND for his kind assistance in the identification of certain species. I. Geography and physiography Ms a general discussion of the position, topography, soil, and climate of the region was presented in the former paper, a con- sideration of these points will be omitted. II. Plant formations A. TREELESS OPEN 1. Beach formation—(a) Lower beach——-The contour of the lower beach varied exceedingly during July 1911, thus indicating t Snow, L. M., Some notes on the ecology of the Delaware coast. Bor. Gaz. 34: 284-306. map and figs. I-Io. 1902. 45] [Botanical Gazette, vol. 55 46 BOTANICAL GAZETTE [ANvARY — an unstable condition. This instability is further evidenced by the fact that, during the 20-25 years which have elapsed since some of the summer residents first visited the region, the beach and the sea-cliff, along which Surf Avenue extends, have receded many feet. After great storms, especially during the winter, the beach is said to be several feet lower, exposing at such times ledges of peaty material. During the period of this study one small ledge nearly in front of Hotel Henlopen, Rehoboth, was twice exposed, Fic. 1.—Ledge of peat in the beach near Henlopen Hotel, Rehoboth, Del. appearing somewhat as in fig. 1. It is said to underlie the coast from Rehoboth to the Henlopen Life Saving Station. One fisher- man reported that in winter a ridge of “turf with stumps in it” 1s exposed in the beach opposite Delaware Avenue. Reference to similar beach-buried peat is made in the report of the Intercol- legiate Geological Excursion, 1911.” : b) Middle and upper beaches.—As was noted in the former paper, no upper beach can be distinguished. This year there is 2 The Intercollegiate Geological Excursion. Science N.S. 34:611-614. I191!- 1913] SNOW—DELAWARE COAST 47 pratically no middle beach, the summer storm-tides usually reaching the bases of the frontal dunes. The succulents character- istic of this zone appear, therefore, around the bases and on the slopes of these dunes. 4 2. Dunes.—Outer series—This series is practically fixed from the Henlopen Life Saving Station to a similar station at Dewey Beach, a distance of five miles. The dunes are held chiefly by Ammophila arenaria, with a sprinkling of Cenchrus tribuloides and succulents. Between these dunes are many passages leading into hollows or lakes which are flooded in times of storm. As the beach is narrowing, the flooding of these regions occurs more frequently than formerly, thus causing a retrogression toward more hydro- phytic conditions. The best example of this is the “flooded area”’ north of Rehoboth, called in the previous paper ,“‘desert waste,” because a large portion of it was at that time bare, damp soil. It is reported to be at times “dry with a shining crust,” but in July ro911, although the month was a rather dry one, the whole area appeared to be under water, thus indicating a greater inflow from the sea. At the south edge of this region are to be found isolated plants of Mollugo verticillata, Sesuvium maritimum, and Spergularia marina (Tissa marina). A second example of flooding __ by the sea is presented by Silver Lake, south of Rehoboth. The presence of numbers of crabs in this lake indicates frequent addi- tions of salt water. This inflow of the sea takes place at a point near the south end of the lake where the margin closely approaches the tide line. Similar retrogressive movements have been described by HARSHBERGER as occurring in northern New Jersey.* As was formerly noted, a region of great activity extends from a short distance south of the Henlopen Life Saving Station to the Henlopen Lighthouse. The large dunes, forming three amphi- theaters opening seaward, have moved many feet inland during the last ten years. In passing back over alternating pine ridges and swamps, they have exposed “‘pine graveyards” and left in bo 2h ide eee Sey ee ee oe” rane ate rd LN yy ig DE a a Oey cg, tc ee hn Ce Sy ae es ET e setae mS fie Aimy ee Se en ee Ree Cee Pes SET On Sree hy ce BO 3 Cow es, H. C., The causes of vegetative cycles. Bot. Gaz. 51:161-183. 1911. : 4 HARSHBERGER, J. W., The vegetation of salt marshes, and of salt and fresh- water ponds of Northern Coastal New Jersey. Proc. Acad. Nat. Sci. Phila. 1909: 373- 400. figs. I-6. 48 BOTANICAL GAZETTE [JANUARY their seaward hollows swamps and ponds, which are at times — flooded by the tide. In the third of these amphitheaters (fig. 2) _ : many slabs of peat may be seen, which have probably been washed inland from the ledge below tide line. Across the cape extends the long dune upon which stands the Henlopen Light. This is the largest dune in the region, estimated ten years ago to be 80-90 ft., when the crest was at the lighthouse. By 1911 the summit had moved about 300 ft. to the southwest, and Fic. 2.—View from the crest of the lighthouse dune, looking south over the third aeipshithentes; flooded area in the distance. appeared to be several feet higher than the base of the lighthouse. This advance has not changed the general appearance of the region, as photographs taken from the same points on both visits are very nearly identical. In spite of the fact that this is an active dune, a small clump of Ammo phila has managed to gain a foothold on the crest (fig. 4). The appearance of the cape after ten years is apparently unchanged. A low beach extends around the point, bordered on the inner side by low dunes, which inclose a complex of dunes and ‘i ? : 3 as 2 rer ASIEN ety SE So et AS Aue Oy Sh ay a ga Ie PS oa oy one a age Bre eee oR ner Gea eer reer Sn Pemen —aeey rere SN ee 1913] SNOW—DELAWARE COAST 49 swamps. A few shrubs appear on the dunes and a low ridge bearing small trees nearly crosses the cape, as may be seen in fig. 5. South of Rehoboth the edge of the frontal ridge of dunes passes into a rolling plain called ‘“‘a heath,” and, although the growth of the shrubs and stunted trees gives the region a more thicket-like appearance, the flora has apparently not materially changed. 3. Hudsonia complex.—North of Rehoboth may still be found the region called a ‘“‘Hudsonia complex,” a jumble of small dunes, Fic. 3.—Eroded face of the lighthouse dune; view taken from the northeast slope. . held principally by Hudsonia tomentosa, with swamps occupying the depressions between them. The flora of these dunes exhibits a more heathlike character than it showed ten years ago. South of Rehoboth the drying of the Hudsonia complex has progressed still farther. Swamps are rather rare, remnants showing in places, where Scirpus americanus(?) and Juncus sp. give evidence of former swampy conditions. 4. Swamps and meadows.—As the flora around Silver Lake was _ studied somewhat more in detail ten years ago than that of the 50 BOTANICAL GAZETTE [JANUARY other meadows, it would have been interesting to have made care- ful comparisons this year. But unfortunately that region has been converted into a pasture, and is closely grazed. The few forms found in the fence corners, however, indicate an assemblage similar to that occupying this region ten years ago. As one passes north- ward the flora changes, many more heath forms appearing this year than at the time of the previous study. This seems to indi- cate that the higher land has become drier, while the land in lower Fic. 4.—View from the top of the lighthouse tenis southwest; this figure is 4 continuation to the right of fig. 2 situations has maintained its swampy meadow character, due to the frequent additions of sea water to the lake. North of Rehoboth, around Frazer’s Lake, there extends a large swamp. Near the lake the cat-tail is apparently the dominant form, while to the east and north this association passes into a meadow which is a second pasture. This swampy meadow extends to the flooded area on the north and has a very uniform appearance. Only the southeastern extension, as it runs between the Hudsonia dunes, was studied. Many typical undrained swamp forms were % q i ¥ r913] SNOW—DELAWARE COAST 51 listed, among which may be noted Spiranthes praecox ? (Gyrostachys linearis?), Viola lanceolata, Juncus scirpoides, Osmunda regalis (O. spectabilis), and Aspidium Thelypteris (Dryopteris Thelypieris). In the Hudsonia complex, as previously noted, are many small swamps. The segregation of species in these swamps is most singular. Neighboring hollows may have almost totally different associations. One may be carpeted with cranberries, while in another, a few feet away, not a plant of this species is to be G. 5.—View taken from the top of the lighthouse — north across the cape; Fic _ Delaware Bay to the left; the Atlantic Ocean to the rig found. The hollows appear to be remnants of the south end of the swampy meadow around Frazer’s Lake, and, with the lake, apparently are not affected by the tidal inflow, which seems to reach only the northern end of the meadow. The hollows and the lake, therefore, show progressive changes. One easily identified pine swamp was rather carefully studied in rgor and again in 1911, with the following result: Osmunda regalis, Aspidium Thelypteris, Vaccinium macrocarpon (Oxycoccus _ macrocarpon), Xyris flexuosa, Rhexia virginica, and Smilax rotundi- 52 BOTANICAL GAZETTE [JANUARY folia have disappeared; while Lyonia ligustrum (Xolisma ligustrum), Ascyrum hypericoides, Eupatorium hyssopifolium, Rubus sp., Vaccinium atrococcum, Gaylussacia baccata (G. resinosa), Baptisia tinctoria, Rhus Toxicodendron (R. radicans), and Quercus mary- landica have established themselves. No sphagnum has been found, and none could be identified in the peat collected. The absence of typical peat bogs from the eastern shore of Maryland was noted by SHREVE,’ although sphagnum was found abundantly in the clay upland swamps. Hibiscus Moscheutos has apparently disappeared from these hollows in the ten-year interval, but whether this is due to the stress of changing ecological conditions or to the assiduous gathering of the plants cannot be stated. 5. Heath—This formation shows a progression toward the development of a forest by a greater growth of the shrubs and trees, without much change from a floristic standpoint. B. WOODED REGION The thicket and forest formations have received no detailed study at either time, but the collections made this year indicate - that the pine stage, represented by Pinus Taeda and P. rigida, is being succeeded by the oak-hickory stage, represented by young plants of Quercus marylandica, Q. alba, Q. velutina, Q. stellata (Q. minor), Q. falcata (Q. digitata), Carya glabra (Hicoria glabra), and C. alba (H. alba). The list of associated forms is incomplete, but it is interesting to note that the species found are not those characteristic of similar situations in New Jersey or southward but that many of the plants found in clay and sandy loam areas of the Talbot terrace of Maryland are present (SHREVE Joc. cit.). According to the manuals, the northern limit of Myrica cerifera, 4 typical pine barren plant, is Maryland. It was found, however, at Rehoboth and is mentioned by STONE’ as occurring in the southern 5 SHREVE, F., The plant life of Maryland. Md. Weather Service, Spec. Publ. II. IgI0. 6 Harper, R. M., Science 25:530-541. 1907. 7StonE, WITMER, The _ of southern New Jersey. Rep. N.J. State Museum. Igio. eS rs a ee YAS, tee PRES Nae ee” Coa ue enn SS peey eg OP Sn ee ees on eeresmreni fa ee Se Sere er oes feet oe ae : Rape is. *S : 1913] SNOW—DELAWARE COAST 53 part of New Jersey. I agree with Stone (loc. cit.), SHREVE (loc. cit.), HARPER,’ and WILtiAMson®? that the flora of south- eastern Delaware has affinities, southward and northward, with districts much farther inland, rather than with the coastal regions. C. THE CANAL DUNE This dune, mentioned in the previous paper as having been formed, about a mile inland, from material excavated in making a canal, is at this time practically fixed. This is due (1) to the fact that the finer sand has been blown away, leaving the coarser material, and (2) to the binding power of plants. No Ammophila is to be found, but many of the plants characteristic of the Hudsonia complex and of the heath are present. III. Problems connected with the region Second series of dunes.—This series was omitted from the fore- going discussion, because of its possible relation to the problem concerning the change in direction of the coast line. This ridge of dunes is best seen north of Rehoboth, extending to the northwest from the end of the board walk, thus making an angle with the coast. It was considered in the previous report (p. 286) to be a ridge of dunes blown from the coast in a south- westerly direction. The dunes lie on a hard, flat foundation of clay and sand impregnated with iron. This is continuous with the bluff along which Surf Avenue lies and with the clay-sand ledge south of the town, shown in fig. 6. ae 6 ‘early For the Continent of Eur tope: Th. Stauffer, ae tess ake 26, ‘Leipzig, Germany. Yeary. subscriptions, grag hse he M. 33 ie single copies, cena, teed M, 3.60 eac ae a ruzen-Kabushiki-Kaisha, 16 Nibonbashi Tori 5a chore 7 ToRpe, Japan. Yearly. chan including postage, Yen 15. eé each; he copies, inclading _ postage, Yen T. .75 each. obi- Claims for missing num umbers s should be made within the seals iollaktuc the regular month of pal cation. 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A table showing appr nme fe of ect itional separet** which a accompanies t the proof; a copy will be sent on reques ‘ 896,. Post-ofce a Chicago, as = secondeclass — under Act sof Congress, March se TG VOLUME LV NUMBER 2 — LIL BOTANICAL GAZETTE FEBRUARY 10913 THE MORPHOLOGY OF ARAUCARIA BRASILIENSIS I. THE STAMINATE CONE AND MALE GAMETOPHYTE L. LANCELOT BURLINGAME (WITH ELEVEN FIGURES AND PLATES IV AND V) Introduction Although wood of the araucarian type, strikingly resembling that of the ancient Cordaitales, has been known for a long time and has been used as evidence of the antiquity of the araucarians and as a proof of their relationship to the Cordaitales, both of these opin- ions have been vigorously challenged. It has been asserted that they are less ancient than the Abietineae and are derived from them (7,9); that possibly they are not related to other gymnosperms at all and have been derived from a lycopod ancestry (17, 18, 20); that “the geological claim for the great antiquity of the Abietineae thus fails on critical study of the two forms upon which it is based” (27); that “the ancient geological and widely separated geographical distribution (of Araucarineae), the large micro- sporangiate cones in comparison with the megasporangiate cones, the evident transition between the sporophylls and the foliage leaves are indications of an interesting and probably primitive group. The anatomy of the microsporophylls and megasporo- phylls indicates that they are homologous structures, functionally differentiated” (26); that ‘unfortunately, no teratological phe- nomena, on which he always laid great stress, were known in the Araucariae, but they were in the Abietineae and showed that 97 98 BOTANICAL GAZETTE [FEBRUARY the single ovule was a modification of an axillary shoot bearing sporangia”’ (30, 31). In the face of opinions so diverse, the desirability of additional facts is very evident. We know already that the pollen grains and pollen tubes of Araucaria contain numerous nuclei, most of which are prothallial or vegetative (13, 24, 25, 26), and that the same condition obtains in Agathis (24), with the added information that there are definitely ‘‘two large male nuclei” (6). Among the Podocarpineae the same conditions are known to be true for Podocar pus (1, 2, 5, 8, 22, 33), Dacrydium (8, 23, 32, 33), Phyllo- cladus (11, 33), Saxegothaea (15, 29), and Microcachrys (28). The present investigation was undertaken in the belief that addi- tional knowledge of the morphology of the Araucarineae would aid very materially in clarifying our ideas concerning the origin (or origins) of Coniferales and the relationship of the Pinaceae, par- ticularly the Abietineae, and the Podocarpineae (and Taxaceae generally). The materials for this investigation have been secured through the kindness of Mr. James C. Fioop of San Francisco, California, from his country place, Linden Towers, at Menlo Park, California, to whom the writer wishes to express his sense of obligation and appreciation. He is also under obligation for actual assistance in making the collections to the generous assistance of Mr. Roacu, the gardener at Linden Towers, to whom also-his thanks are due. Collections were begun in March 1910 and made weekly up to the middle of November, when they were interrupted by illness until February 1911. Collections were again made from November 15, 1911, to February 1912, thus completing the series. Various killing and fixing agents have been tried. A solution recommended by Juet (10) gave as satisfactory results as any for most stages. Flemming’s stronger solution, as well as the chrom- acetic mixture recommended in CHAMBERLAIN’s Methods in plant histology, also gave good results for some stages, but fails to penetrate the microsporangium during the development and division of the mother cells, owing partly to the nearly impervious epidermis that develops about this time, and partly, perhaps, to the presence then in the pollen sacs of a sort of mucilage, apparently produced by the 1913) BURLINGAME—ARAUCARIA BRASILIENSIS 99 degeneration of the walls of the mother cells. At certain times in mid-winter practically all stages of the cones are present on the trees at the same time. Notwithstanding the fact just mentioned, stages between the prophase of the mother cell and tetrads were collected only four times, though diligently sought for. The same is true of the stages in the development of the gametophyte from mature microspores to those in which the primary spermatogenous Fic. 1.—Forest of Araucaria brasiliensis on the Rio Tibagy, State of Parana, southern Brazil -—Photograph by J. C. BRANNER. cell has already divided. The reasons for this state of affairs are not very apparent, though it may be that these stages are passed through very rapidly or that division occurs during the night. The habit of the tree is shown in text fig. 1, representing old trees in their native habitat, and in text fig. 2, an ovulate tree from the gardens at Linden Towers. The staminate cone Among the numerous specimens of Araucaria in these gardens, belonging to at least four different species, there are three staminate I0o BOTANICAL GAZETTE [FEBRUARY ones of A. brasiliensis. They are about 30 years old and range in height from 25 feet to about 60 feet. The largest one is about 20 inches in diameter. Most of the collections were made from the smallest tree because it has had the crown broken out, and on this account fruits much nearer the ground, a matter of some Fic. 2.—Ovulate tree from gardens at Linden Towers, showing retention of lower branches in young trees. consequence when one considers ways and means of securing cones from a ‘monkey puzzle” tree. This tree was selected for the additional reason that the range of stages on it at any time was greater. It had moreover the peculiarity of forming its cones much earlier in the fall and continuing to form new ones later in the 1913] BURLINGAME—ARAUCARIA BRASILIENSIS Ior spring. Numerous collections were made from one of the other trees in order to make sure that development in the cones from all the trees was the same. Fic. 3.—Staminate branch of A. brasiliensis bearing two old cones of previous season oa several young ones; note the new shoot from one of the old cones. In the fall (August to October) one finds the shoots of A. brasiliensis tipped with terminal buds, in some of which, distin- guished by being larger and plumper, one can find the very young cones. As soon as the branch has developed from such a bud, one 102 BOTANICAL GAZETTE [FEBRUARY usually finds about 3-6 staminate cones scattered along the new shoot (text fig. 3). Each cone terminates a short leafy branch, which may occasionally continue its growth the following season, but usually the cone dries up, turnsebrown, and falls off the winter following the shedding of its pollen (text fig. 3). The mature cones are very large, immediately after having shed their pollen being frequently as much as 15 cm. long and 3 cm. in diameter; they are about one-third smaller before shedding. Text fig. 4 shows an unopened cone, a cone shedding its pollen, and the apical view of a mature cone broken in two, about natural size. Suchaconeasis — shown in the photograph has about 1000 sporophylls, disposed in about 12 spiral rows, each of which makes 2 or 2.5 turns. There are usually 10-15 sporangia, pendent (text figs. 5 and 6) from the expanded distal portion of the sporophyll on its morphologically abaxial side. Each sporangium contains 500-1000 pollen grains. A little calculation will show that the output of a terminal bud may easily reach a billion pollen grains. The pollen is shed in the spring from the first of April to the latter part of May for the most part, although I have found cones shedding in December and as late as July 1. The sporangia dehisce through longitudinal slits on the sides of the sacs facing the other row of sporangia, so that the pollen is shed into the space between the inner and outer rows of sporangia. By dissecting the terminal buds already referred to, one can recognize the young cones when they are merely rounded growing points. Each one is enveloped in two or three layers of delicate leaves and is slightly flattened on the side next the main axis of the bud. Plate fig. 1 shows a slightly older cone, on which the first sporophylls are forming. A sporophyll is first recognizable as 4 group of meristematic cells (plate fig. 2) just beneath a slight emergence of the smooth surface of the growing point (plate fig. 1)- This emergence increases in size rapidly by growth throughout. Very soon its distal end expands until the whole structure somewhat resembles a mushroom with a very short stalk and one-half of the pileus removed. The stalk is so short that the abaxially placed swollen portion of the sporophyll is in contact with the cone axis. ‘From its surface grow the sporangia, elongating toward the cone 1913] BURLINGAME—ARAUCARIA BRASILIENSIS 103 4.—Cone shedding stint (to right), + Fr of ar: cone; natural size. unopened cone, and cross-section 104 BOTANICAL GAZETTE [FEBRUARY axis as fast as the axis of the sporophyll itself elongates. Like the _ sporophyll itself, the sporangia are first distinguishable as meri- ie Fics. 5-9.—Fig. 5, cross-section of sporophyll, showing relation of sporangia to one another and to the stalk; fig. 6, longitudinal section of a sporophyll, showing position of sporangia and course-of their vascular supply; fig. 7, cross-section of a _ vascular bundle of sporophyll; fig. 8, cross-section of a sporangium at mother cell stage, showing sporogenous cells (s), tapetal cells (¢), 4-6 layers of wall cells, tannin- filled epidermal cells, and thin cells where dehiscence will take place; 250-; 8-9 annulus and stomium just before dehiscence; X 250. stematic outgrowths consisting of several cells. Plate fig. 3 shows part of three sporangia adjacent to one another in the same row, and plate fig. 4 shows a section at right angles to it, showing the Stee yr 1913] BURLINGAME—ARAUCARIA BRASILIENSIS 105 beginnings of two sporangia adjacent to one another but in differ- ent rows. Occasionally one can distinguish what appears to be the archesporium almost as soon as the sporangium itself is recog- nizable, but much more commonly it cannot be detected until the sporangium is 12-15 cells in length and 8-10 cells wide (plate figs. 4, 5, 6). Not infrequently sporangia as far developed as that shown in plate fig. 7 do not show any differentiation of sporogenous cells. Ordinarily one can recognize all the primary regions of the sporangium at this stage. The cells of the tapetum seem to be derived more or less indifferently from those of the wall layers outside, or from derivatives of the inner and presumably sporoge- nous cells. However, I should not like to be too dogmatic in regard to this. Multiplication of cells continues until the sporogenous tissue consists of a mass some 20 cells in cross-section (plate fig. 8) and 40-50 cells long. The tapetum remains one or two cells thick, the ultimate cells being elongated radially and retaining their position and structure till some time during the development of the male gametophyte. At this time there are 4-6 layers of wall cells radially flattened, with very little cell contents. The epidermis is at this time filled with a densely staining substance, resembling tannin in its staining reactions, and presenting a very effective barrier to the ready penetration of the ordinary reagents. In the further development of the sporangium the contents of these epider- mal cells disappear, and the radial walls, seen in a cross-section of a sporangium, thicken in the fashion of a fern annulus, except at the point of future dehiscence. The wall cells are eventually crushed and more or less destroyed and the tapetum finally dis- integrates (text figs. 8 and 9). Sporogenesis After the last division of the sporogenous cells, the mother cells begin enlarging, until at the prophase of the heterotypic division they have attained a diameter more than twice that of the sporoge- nous cells. This eight or ten times increase of volume is largely water, the cytoplasm becoming greatly vacuolated as the growth increases. There is a corresponding enlargement of the nucleus, 106 BOTANICAL GAZETTE [FEBRUARY though not proportionally so great (plate fig. 9). Once this increase in size has been effected in the mother cells and their walls, the cell contents appear to round up and shrink away from the walls more or less; just how much I am unable to say owing to the difficulty of determining whether part or all of the shrinkage may not be due to the difficulties of securing satisfactory fixation. The walls themselves have a tendency to persist until after the young spores have been formed, but apparently they change their chemical condition and become more or less mucilaginous in character. Sometimes no walls at all are visible, but the spaces among the mother cells are filled with a thin sort of mucilage. The greater the amount of this mucilage present, the poorer the fixation. Owing to the difficulties already mentioned, I have but little trustworthy information concerning the course of events during the reduction divisions. Stages in the formation of the presynaptic spireme, synapsis, and diakinesis were observed. At the metaphase of the heterotypic division there are 8 bivalent chromosomes, but the material did not permit one to follow the method of their formation. The spindle fibers are attached to their apices (plate fig. 11), and they are drawn apart as short stubby masses and collect at the pole in a close mass. They appear at the spindle of the homeotypic division as much longer rods curved into more OF less U-shaped chromosomes. No walls are formed, apparently, until after the spore nuclei have passed into the resting condition, when a system of fibers is present between the nuclei, on which the plasmatic membranes separating the young spores arise (plate figs. 13 and 14). The young spores now form walls around themselves, entirely within the old mother cell wall if it is still present. The spores then begin a slow enlargement and thickening of the walls. At first the growth consists merely in enlargement of the wall without any apparent increase of cytoplasm or nucleus. There is either on¢ very large vacuole almost entirely filling the spore or many sma ler ones separated by only the most tenuous cytoplasmic walls. this time no inclusions of starch or other food materials are visible. After the spore wall has reached its mature size, but not final thickness, the cytoplasm becomes more abundant and the nucleus enlarges (plate figs. 16 and 17). In the large nucleus there is a larg¢ eae i ee Ne tes Bra) eae tees # Be sph: tk Seine F ene ea se ot eae Aji Seda ON Oe Woe ro ee aay ee es aoe ce ee So aa ee ii bareiaiicis a 2S ics er ee ok ek i eM og a iy 5k = Tes aa 1913] BURLINGAME—ARAUCARIA BRASILIENSIS 107 nucleolus and rather scanty chromatin. From this is organized a rather long, loose spireme, apparently containing scanty chromatin. It segments to form 8 chromosomes, which contract into rather small dense oval masses (plate fig. 18). Male gametophyte The results of this first division are a primary prothallial cell and a free nucleus (plate fig. 19). The latter at once divides to produce a second prothallial cell, which takes its place over the preceding. The next division yields the free tube nucleus and the primary spermatogenous cell (plate fig. 21). Meantime the pro- thallial cells have divided (plate figs. 20, 21, 22). The primary spermatogenous cell now divides, yielding the usual stalk and body cell. The stalk cell is very evanescent, usually becoming confused with the general cytoplasm very quickly, Plate fig. 25 shows one of the few preparations in which it could still be distin- guished as a distinct cell. Another interesting case was observed in which there seemed to be two free and equal cells in the unshed pollen grain. The usual condition of a mature pollen grain, with 15-25 free prothallial nuclei, a recognizable tube nucleus, and a single body cell, is shown in plate fig. 27. It is in this condition that the pollen is shed in April (usually). The potential number of pollen grains is four to eight times as great as the actual number formed. It has already been remarked that the ordinary number of mother cells is about 1000, while the usual number of pollen grains that mature in a sporangium is only 500-1000. At the time they are shed the pollen grains have a two- layered wall, the outer coat of which easily separates from the inner (plate figs. 25, 26, 27), but which does not appear to do so naturally to form wings. At the time they are shed they contain a great many very large starch grains, a few of which are shown in plate fig. 27. They are usually so crowded with it that the microtome knife scatters the contents all about in cutting sections of shed pollen Pollination The ovulate cones are first recognizable in late April. At this time there is no trace of ovules on the scales and the pollen lodges somewhere near the free edge of the so-called ligule (text fig. 10). 108 BOTANICAL GAZETTE [FEBRUARY Whether the pollen shed in the early part of the season finds a lodgment in a position to become effective is uncertain. Neither does there appear to be any available data as to whether this precocious shedding of pollen occurs in its native habitat. Though California and Brazil exhibit a somewhat rough correspondence in their seasons of rainfall and plant growth, yet it is probably not sufficiently exact to permit of any very satisfactory inferences as to the corresponding behavior in the two habitats. | I have not yet ascertained cer- tainly how long a time elapses after the pollen falls on the scale before germination occurs. Grains that have germinated can be found in the latter part of summer after the fogs have set in. Meantime during the summer the ovule is forming and the stigmatic nucellus is usually ready to receive the ad- Fics. 10, 11—Fig. 10, ovule and sep agate ene on scale in December, showing course of m September or October. ‘ pollen tubes; fig. 1x, course of pollen I have not so far succeeded in tube through nucellus to archegonium. germinating pollen to any very advanced stage, nor have I been able to follow with any certainty the course of events in the pollen tube before it reaches the nucellus. When the ovuliferous scales are pulled apart, very numerous pollen tubes are usually found sewed back and forth between the two adjacent surfaces of the scales. One can sometimes isolate one without completely de- stroying it, but I have learned from such preparations nothing more than that there are numerous nuclei and a body cell present. One could infer that they would be there, inasmuch as they were in the pollen grain, and they are afterward present in the tu when it enters the nucellus. Whether division of the prothallial nuclei occurs in the tube or not is uncertain, owing to the fact that I have never been able to obtain an entire tube in which I 1913] BURLINGAME—ARAUCARIA BRASILIENSIS 109 could count the nuclei and be sure of having seen them all. These nuclei do increase markedly in size, and much of the starch which entered the tube at germination disappears before penetration of the tube into the nucellus. At the time that the tube enters the nucellus there are numerous nuclei and the body cell present. I was unable to distinguish the tube nucleus any longer from the others. At first only a few of these nuclei enter the portion of the tube in the nucellus. The body _ cell is usually in that portion just outside of the nucellus or just barely within it. There is apparently very little activity in the development of the tube from the time it first penetrates the nucellus for a short distance until spring. I did not succeed in finding the mitosis concerned in the division of the body cell, though the two male cells were found two or three times still imbedded in a common mass of dense cytoplasm. The two nuclei frequently differ in size markedly. The body cell and its nucleus have increased in volume after leaving the pollen grain some six or eight times by the time _ the pollen tube has penetrated the nucellus in October (plate fig. 28). This increase continues on an even greater scale up to the time of division. After the division of the body cell, one, at least, of the pieces organizes itself into a large male cell or perhaps a real sperm. ‘These vary considerably in size and in the definiteness of their organization. They all agree in being very large and in being more or less completely delimited from the cytoplasm in which they are imbedded (plate fig. 29). Almost invariably the large nucleus is at the extreme end of the cytoplasm and the cytoplasm is very often evidently arranged in such a way as to lead one to surmise that the nucleus actively changes its position in reference to the cytoplasm. The nucleus is invariably at that extremity which would lead in the direction that the ‘‘sperm’’ would be inferred to be moving. The cytoplasmic body is sometimes bent, almost at a right angle in one instance observed, in such a way as to remind one strongly of the creeping movements of an amoeba. In one instance of two “sperms” lying in a common mass of cyto- plasm, apparently having just divided, there was present a peculiar fibrillar structure reminding one of a nuclear spindle without the _ chromosomes and with an aster at either pole. Whether this is IIo BOTANICAL GAZETTE [FEBRUARY an indication of the presence of a blepharoplast and whether the “‘sperm”’ is actually motile, I hope to be able to ascertain during the coming spring. The division probably occurs in the latter part of February and in the part of the tube outside of the nucellus. During this time the pollen tube has advanced through the nucellar tissues in a more or less irregular and branching course. When it reaches the upper part of the female gametophyte it usually turns aside from the apex, which is protected by a cap of crus nucellar cells, and creeps laterally along the surface of the gameto- phyte until it reaches the narrow opening leading down to one of the archegonia, down which it descends to the neck of the archegonium. Here it becomes perforated. The “sperm’’ passes through the opening and crowds the neck cells of the archegonium apart without destroying them, and plunges down into the egg so vigorously as to leave a very distinct wake behind it in the cytoplasm. Fertilization occurs in the latter part of March or first week or two of April. Discussion It is not proposed at this time to enter into any general discussion regarding the broader questions that prompted the investigation, but to let that await the issue of further investigation of other phases of the life history of this species and of the other three species of which material is available. However, it may not be amiss to point out that this added information concerning the male gameto- phyte goes far toward inducing a belief in the primitive condition of the araucarians. It certainly strengthens the resemblance to the podocarps and tends to increase our confidence in their genetic connection. Barring the abnormally large ‘‘sperms” of Araucaria and the greater number of prothallial nuclei, its male gametophyte exhibits an almost identical structure even in small details wi that of the Podocarpineae. On the contrary, it is clear that the type of male gametophyte found in these two tribes is essentially different from that found in Cupressus Goveniana (10) and Juniperus communis (14). In these we have a multiplication of spermatoge- nous cells, which may be induced, as has been suggested, by the opportunity for more than one sperm to function, but in any case is doubtless a reversion to an ancient habit (10, 14). This view 1913] BURLINGAME—ARAUCARIA BRASILIENSIS IIL is strengthened by the occurrence of more than two sperms in Microcycas (3) and Ceratozamia (4). The deposition of the pollen at a distance from the nucellus has also been recorded for Saxe- gothaea cons picua (15), and serves to strengthen the likeness of the araucarians and podocarps. By long odds the most interesting and suggestive feature of the male gametophyte of the araucarians yet known is the remarkably large ‘‘sperms”’ and the possibility of their motility. The one figured (plate fig. 29) is about 150 long. It is by no means the largest one observed, but seemed to be the one most definitely organized. Such dimensions are only known elsewhere among the actively swimming sperms of the Cycadales and Gingko. It is of interest to note that the kauri (6) appears to have two large nuclei also, though it is not stated that they constitute part of organized cells. Inasmuch as Agathis has usually been held to be more primitive in most respects than Araucaria, it may be possible that they will yet be found there. The aster-like fibers found in the dividing body cell are of course very suggestive of a blepharoplast, and one might perhaps legitimately expect such structures to be found in connection with such large and possibly motile male cells. Again they might be only such structures as have been recorded by LAND (12) in the egg of Ephedra. Summary 1. The staminate cones are extraordinarily large and have numerous sporophylls with an indefinite number of pollen sacs pendent from the abaxial side of the swollen apex. 2. An almost incomprehensibly great number of pollen grains is produced. 3. The method of differentiating the sporogenous tissue is variable and indefinite. The size of the sporangium and the number of microspores is subject to wide fluctuations. 4. The structures concerned in dehiscence are very fernlike. 5. The chromosome number in the male gametophyte is 8. 6. Prothallial tissue is formed in a manner almost identical with that in the Podocarpineae, but the number of cells so formed is greater. 112 BOTANICAL GAZETTE [FEBRUARY 7. The pollen is shed with numerous prothallial nuclei, stalk nucleus, tube nucleus, and body cell free in it. 8. The pollen does not fall upon the nucellus but upon the ovuliferous scale at a considerable distance from the position of the ovule. g. About a year elapses between pollination and fertilization. to. No ovule has yet been formed on the scale at the time of pollination and the pollen tube does not reach the ovule for 5 or 6 months afterward. 11. The body cell is single, at least usually, and large. 12. Two male cells (sperms perhaps) are formed and are usually unequal. 13. There may be a blepharoplast-like body associated with the division of the body cell. 14. Fertilization occurs about the first of April. STANFORD UNIVERSITY CALIFORNIA LITERATURE CITED 1. Brooks, F. T., and Stites, WALTER, The structure of Podocarpus spinu- losus. Ann. Botany 24: 305-318. pl. 2z. IQ10. 2. BurtincAME, L. L., The staminate cone and male gametophyte of Podo- carpus. Bot. Gaz. 46: 161-178. pis. 9, 10, 1908. 3. CALDWELL, Oris W., Microcycas calocoma. Bor. Gaz. 44:118-141. Dl. 10-13. figs. 14. 1907. CHAMBERLAIN, C. J., Morphology of Ceratozamia. Bor. GAZ. 53:1-19: pl. 1. figs. 7. ae 5. Coker, W. C., Notes on the oo and embryo of Podocarpus. Bor. Gaz. 33:89-107. pls. 5-7. 6, Eames, ArTHuR J., The cphsies of the kauri. Science N.S. 35° 160. 1912 7. JEFFREY, E. C., and Curyster, M. A., On Cretaceous Pityoxyla. Bot GAZ. 4231-15. pls. 1, 2. 1 , The microgametophyte of the Podocarpineae. Amer. Nat. 41: 355-364. figs. 5. 1907 Jerrrey, E. C., Araucaryopitys, a new genus of araucarians. Bot. GAz- 44:435-444. pls. 28-30. 1907. 10. JuEL, H. O., Uber den Pollenschlauch von Cupressus. Flora 93: 56-6? pl. 3. 1904. 11. Kirpan, N. J., The morphology of Phyllocladus alpinus. BOT. Gaz. 49: 3390-348. pls. 20-22. 1908. a ey Na ET FER ey eee es ee oe 1913] BURLINGAME—ARAUCARIA BRASILIENSIS a 12. Lanp, W. J., Fertilization and embryogeny in Ephedra irifurca. Bor. - 44: 273-292. pls. 20-22. 1907. 13. Lopriore, G., Uber die Vielkernigkeit der Pollenkorner und Pollen- schlauche von Araucaria Bidwillii. Ber. Deutsch. Bot. Gesell. 23: 335-346. pl. 15. 1905. 14. NicHots, GEorGE E., A morphological study of Juniperus communis. Beih. Bot. Centralbl. 25: 201-247. pls. 8-17. 1910. 15. Noren, C. O., Zur Kenntniss der Entwicklung von Saxegothaea conspicua. Svensk. Botanisk eae the 2: 101-122. pls. 7-9. ee 16. OLIVER, F. W., On the st d affinities of S p Trans. Linn. Soc. London II. 6: 361-400. pls. 41-44. 17. RENAULT, B., Structure comparée de a aes. ve . flore carbonifére. Nouv. Arch. Mus. Hist. Nat. IT. 2: 348. pls. 18. , Cours de botanique fossile. he 1880-1 a 19. SAxTON, W. T., Contributions to tg life history of Callitris. Ann. Botany 24:557-560. pls. 45, 46. 1 20. SEWARD, A. C., and Forp, ae 5 The Araucaria, recent and extinct. Phil. Trans. Roy. Soc. London B 198: 305-412. pls. 23, 24. 1906. 21. SEWARD, A. C., “The ee of gymnosperms,” at the Linn. Soc. New Phytol. 5: rant, 148. 1906 22. SINNOT, Epwarp W., The gametophytes of Australasian podocarps. Science N.S. 35:160. 1912. 23. STILES, WALTER, A note on the gametophytes of Dacrydium. New Phytol. > Ls . 24. THOMPSON, ROBERT Bown, Preliminary notes on the Araucarineae. Science N. S. 22:88. 1905. , A protosiphonogamic method of fertilization. Science N.S. 25: 271-272. 1907. 26. ———, a origin of gymnosperms,” at the Linn. Soc. New Phytol. 5°144. 25. 27. De es Abietineae extend to the Carboniferous. Science N.S. 38: 150. Igi2. 28. , On the pollen of Microcachrys tetragona. Bor. GAz. 47:26-29. pls. 1, 2. 19009. 29. Tison, A., Sur le Saxegothaea conspicua. Mem. Soc. Linn. Normandie 23:139-160. pls. 9, IO. 1909. 30. WorspeLt, W. C., “The origin of gymnosperms,” at Linn. Soc. New Phytol. 5:146. 190 , The secteur of the female flower in Coniferae. Ann. Botany 14239-82. 1g00. 32. Younc, Mary, The male gametophyte of Dacrydium. Bor. Gaz. 44: 189-196. pl. 19. 190 , The sionpholoay of the Podocarpineae. Bor. Gaz. 50:81-I00. pls. $6. IgIo. $7. 33. II4 BOTANICAL GAZETTE [FEBRUARY EXPLANATION OF PLATES IV AND V All figures have been drawn under Zeiss apochromatic objectives and compensating oculars with the aid of a camera lucida. Figs. 2-8 were drawn with 4 mm. obj. and compensating ocular 6; figs. 9-27, under obj. 3 mm. and ocular 12; figs. 28 and 29, under 3 mm. obj. and compensating ocular 6. Fig. 1.—Longitudinal section of a young cone from a terminal bud: s¢, ous lea Sp, set sporophyll; vb, vascular bundle; X12 ial meristem of very young sporophyll drawn from same Spe a prea 1G. 3.—Cross-section of a cone showing the sporangial meristems; X250. Fic. 4.—Longitudinal section of cone of same age as preceding: section passes through the stalk of the sporophyll and through the primordia of one sporangium in each row; c.ax, axis of cone; x2 ‘nt Fic. 5.—Transverse section of cone and long ction of sporangium: sporogenous tissue not defined; X 250. Fic. 6.—Same as fig. 5, but showing usual differentiation of sporogenous ae hase X 250 G. 7. Vedat stage of differentiation of tapetum (4); X25 oe 8.—Cross-section of sporangium after last eae division; X 250. Fic. 9.—Somewhat shrunken mother cell showing eight times increase in volume; X770 Fic. ro. —Portion of a nucleus in which the heterotypic chromosomes are forming; le Fic. 11 the 8 heterotypic chromosomes; 770. Fics. 16 and 17.—Mature microspores; 770. Fic. 18.—Division of microspore nucleus; 770. Fic. 19.—Showing first prothallial cell the ee Sy io Fic. 20.—Mitosis of a prothallial cell; 770. Fic. 21.—Showing two tiers of prota (pe’ pe’’), primary sperma- togenous cell (.s.c.), and tube nucleus (#); Fic. 22.—Division of primary sone Aaa de cell; X770. Fics. 23-26.—Series of transverse sections of a pollen grain: pc’, basal tier of prothallial cells; pc’, second tier; im, tube nucleus; bcn, body cell nucleus; bc, body cell; sc, stalk cell; scn, stalk cell nucleus; 770. Fic. 27.—Shedding stage of pollen grain; 770. Fic. 28.—Body cell about October 15; 385. Fic. 29.—A male cell just before fertilization; 385. 4 BOTANICAL GAZETTE, LV PLATE IV oo ) == oS O ges ge at the Post -office at ica, so isa cacy matter under A Act of Gowen ae: 3, 1879 VOLUME LV NUMBER 3 Se a Cee Oe ee TER ere gee eel ST ERE es eee Peng Oe : ; 3 INHERITANCE OF FLOWER SIZE IN CROSSES BETWEEN SPECIES OF NICOTIANA’ E. M. East : THE : _ BOTANICAL GAZETTE ‘ MARCH 1913 (WITH PLATES VI-X) Since the independent investigations of Nmtsson-EHLE and of the writer demonstrated the feasibility of using the Mendelian notation to describe the inheritance of size characters that blend in the first hybrid generation, a number of botanical papers have appeared that supported this interpretation. These papers have considered the behavior in crosses of such characters as height of plant, size of leaf, number of leaves, time of flowering, and size of fruit. If the number of leaves in certain plants is excluded, this type of character is one particularly affected during development by external conditions. Since fluctuations produced in this manner are not transmitted, if the conclusions drawn from the sum total of our limited experimental cultures are to be given weight, the validity of the evidence in these investigations is not disturbed. At the same time, one must admit that these fluctuations obscure an analysis of the crude data. For example, plant B may be six inches higher than plant A when both are grown in the same envi- ronment, owing to a different heritage, but plant A may grow con- siderably higher than plant B if the environment of A is the best possible for maximum growth and the environment of B is poor. In this paper, therefore, I propose to consider the inheritance of * Contribution from the Laboratory of Genetics, Bussey Institution of Harvard “si y. Pe cre Pe ey te a? eee ee ge Bee one Fp 8 NC vee peated was eet tt Bear re Seay ance Universit pin 178 BOTANICAL GAZETTE [MARCH a character-complex which I believe to be the least affected by external conditions of any character that shows marked varietal differences. This character-complex is corolla size. The fact that corolla size is so comparatively constant under all conditions attend- ing development has such a definite bearing on some broad ques- tions of organography that it merits separate discussion. On this account, the liberty of asserting the truth of the statement with only the following data in its support is requested. During the past four years, I have grown about 20 species of Nicotiana in considerable numbers. They have been grown under very diverse conditions. Some have been starved in four-inch pots, others have had the best of greenhouse treatment; some have had poor field conditions, others have had all field conditions practically at their best. The height of the plants, the size of the leaves, and similar size complexes have varied enormously, but the size of the corollas has scarcely varied at all. For example, plants of Nico- tiana silvestris Speg. and Comes grown to maturity in four-inch pots produced no leaves longer than 7 in. On the other hand, sister plants of the same pure line produced leaves 30 in. long in the field. Both series, however, produced flowers with the same length and spread of corolla. Furthermore, cuttings from 20 of the field plants reported in this study were rooted and grown in small pots in the greenhouse. Their blossoms were the same size as _ those of the field grown plants from which they came. The material used in this particular experiment consisted of pure lines of two Nicotiana types that are generally treated as distinct species (pl. VI). The male parent was Nicotiana alata grandiflora Comes, it being the plant called Nicotiana affinis by horticulturists. Three lots of it were under observation; one was obtained from Italy and the other two from the United States, but the original sources of the strains are unknown. These three lots were alike, and in successive generations were constant in their characters. They accorded perfectly with Comes’ description and were remark- ably narrow in their variability. The female parent I have called Nicotiana forgetiana, Hort. Sand., and thereby hangs a tale. 1 found in the Gray Herbarium of Harvard University a sheet from near Los Angeles, California, marked Nicotiana clevelandii Gray. am SS ‘en tei ag Wines ite See 1913] EAST—CROSSES OF NICOTIANA 179 This designation was manifestly incorrect, as the plant was exactly like SANDER’s figure of N. forgetiana in the Botanical Magazine (No. 8006). As it had been collected only a few years, I took seed from one of the capsules and planted it. It grew and again pro- duced plants like N. forgetiana. Miss Day, the librarian of the Gray Herbarium, then looked up the correspondence regarding the specimen and found that it was evidently a garden specimen grown by a Californian botanist, since deceased, from seed fur- nished by Sander & Sons and called N. Sandarae. The plants have not the mixed colors and the variability of the specimens now sold as Sandarae hybrids, but are constant in their characters and are identical with Nicotiana forgetiana. I have come to the conclusion, therefore, that I have obtained (as Lock? probably did) seeds of the real NV. forgetiana that had been mixed with the Sandarae’ hybrids by Sander & Sons. In view of the fact that NV. alata grandiflora and N. forgetiana do not differ essentially in their foliage and habit of growth, but only in flower size and color—the one being white, the other red—per- haps one should not call them two species. I hold no brief either way. Isimply accept the taxonomic ruling. At least, there existed here two strains very different from each other and very constant in their characters. Both were self-fertile, and in fact were usu- ally self-pollinated naturally. They were crossed. There was no trouble about this, as every cross attempted was successful, and the capsules were filled with seeds. This, then, seemed to be an excellent opportunity for studying size inheritance: two strains, uniform in pure lines, one with a corolla three times the length of the other, could be crossed easily. All was not plain sailing, however, for the plants of the F, genera- tion (pl. VII) were absolutely self-sterile. This fact would have cut off the experiment in the flower of a promising youth but for the further fact that each plant was perfectly cross-fertile with every other plant. It did indeed reduce my interest in the inheritance of corolla size, for it precluded the study of an F; generation, but this was offset by the more fascinating problem of self-sterility. 2 Ann. Roy. Bot. Gard. Peradeniya 4:195-227. 1909. 3 The Sandarae hybrids were supposed to have been produced by the cross V. forgetianaXN. alata grandiflora. 180 BOTANICAL GAZETTE [MARCH It was impossible to study the F generation because crosses between two F, individuals alike somatically would be without meaning, since nothing could be known of the gametic potentiality of each. Crosses between F, individuals, on the other hand, meant some- thing, because they were alike gametically. Six F, crosses were made therefore, and from them were grown 828 plants. TABLE I FREQUENCY DISTRIBUTIONS FOR LENGTH OF COROLLA IN A CROSS BETWEEN Nicotiana forgetiana AND N. alata grandiflora Class centers in millimeters Designation eae 20 | 25 | 30| 35| 40] 45 | 50| 55 | 60| 65 | 70] 75 | 80) 85 | 99 +5 oi Seemgeaiay fei cs. Eons ee a Gs SO i a ar) Chiat Remy Cantar Geir emery ar DSU Oe acai ys Ouray ew gee ee ba clea locales ifs] TO} 50] 50 Bale (pos Peony mee She pe aS satay (ies eteta “oles Cours Boras pokey a ¥, taX3et) 1-6... .-| 5] 27] 79|136|125|132|102|r05) 64) 30] 15) 6} 2) -- Table I shows the frequency distribution for length of corolla of N. forgetiana (314) inbred, N. alata grandiflora (321) inbred, the F, generation (314X321), and the F, generation (314X321) 1-6. The measurement was taken from the end of the pedicel to the center of the contraction commonly known as the corolla throat. The classes have a magnitude of 5 mm. and are centered at the even centimeters and half-centimeters. A glance at the distributions themselves is sufficient to show the small variability of the parent types and of the F, generation, and the great variability of the F. generation. The F, generation is strictly intermediate, as is the mean of the F, generation. Among the individuals of the F., genera- tion, however, are flowers identical with each parent. This last fact is perhaps more clearly shown in the figures of pls. [X and X. The statistical constants for each frequency distribution are shown in table IT The spread of the corolla, measured to the tips of alternate lobes, behaved in the same way. Corolla breadth in N. forgetiana varied from 25-35 mm., with a sharp mode at 30 mm. The corolla spread of NV. alata grandiflora was somewhat more variable in terms of the arithmetical standard, ranging from 55 mm. to 80 mm. The range of the F, individuals extended from 45 mm. to 55 mm. 6 i Us 1913] EAST—CROSSES OF NICOTIANA 181 In the F, generation plants were produced with a corolla breadth identical with each parent. In fact, there were four individuals as small as the smallest specimens of N. forgetiana, and there was one individual with flowers within 3 mm. of the size of those of the largest N. alata grandiflora growing in my cultures. The mean of this distribution was 48.57 +o.19 mm., the standard deviation 8.07 0.13 mm., and the coefficient of variation 16.62+0.28 per cent. TABLE II STATISTICAL CONSTANTS FOR FREQUENCY DISTRIBUTION OF TABLE I Designation Mean Standard deviation | Coefficient of N. peg AA eee 25.60.12 2.27+0.08 8.86+0.33 meme OF., $97) ie 78.80.28 5.380. 20 6.820. 25 F; (314 S328) ice Wis eel eis 44.30.23 3-67%0.17 8. 280.38 Wa tata 39%) 1-65.06. 49.90.26 I1.26+0.19 22.57=0.39 Examination of the F, generation of this cross indicated a correlation between the length of the corollas and the lengths of the filaments and the styles that for all practical purposes was perfect. By this statement I mean that the anthers were invari- ably just above the stigmas and the stigmas were invariably at the throat of the corolla. Of course absolute measurements would not show an integral coefficient of correlation, nevertheless one may assume, I think, that the fact is simply obscured by slight fluctuations. It seems as if the numbers were adequate from which to conclude either that the determiner or determiners of corolla length are also determiners of the length of the style and the fila- ment or that these factor complexes are perfectly coupled in inheritance. Corolla spread is also correlated with corolla length. It is by no means uncommon to find a sharp break in the correlation, as is witnessed by the individual with the very broad corolla and comparatively short tube pictured in pl. X, fig. 8; but one never s inverse extremes in the same individual. Just what the correlation coefficient 0.610.015 would prove to mean if indi- vidual analysis of later generations were made, is doubtful. We cannot go back of the gross statement that such a correlation exists 182 BOTANICAL GAZETTE [MARCH in the general population. Perfect coupling of certain factors together with independent combination of others may be possible; partial coupling arising from a peculiar gametic distribution may be equally possible. TABLE Ill CorRELATION BETWEEN LENGTH AND SPREAD OF COROLLA IN Fz GENERATION OF CROSS BETWEEN J. forgetiana AND N.. alata grandiflora Breadth of corolla in millimeters Length of corolla in millimeters 25 30 35 40 45 50 55 60 65 7° det BOBS 25 I 4 gee Boe 5 fa | toll 3 |. 3 ee 35 I 5 17 26 a1 6 3 Bik 40 6 2 25 1. 41 31 7 I 136 45 8 20°} 26 {> 31 26 8 2 I ibe 5° 3 a2} 730 |. aA | 225 7 I 132 55 I A ei Na es a 9 4 Fag 60 I 3 II 32 20 19 9 I 105 65 Ot eF 1b. at | 82 7 are is 70 [ I 5b as 4 4 30 75 7 3 4 I 15 80 I I 3 2 6 85 I I an 4: | 16 50 | 122 | 164 208°} 167 | 67 |. 28 4 ae cot! Coef. cor. 0.6100.015 These are the principal facts collected regarding this cross, if the small leaf differences and other minor variations are left out of consideration. How unimportant the latter are, can be seen by a reference to pl. VIII. There are several suggestions that may be made regarding the simple facts obtained, however, that may be helpful in further Mendelian interpretations of size complexes. Elsewhere‘ it has been shown that the behavior of such char- acters in crosses is adequately represented by the segregation and 4 Amer. Nat. 44:65-82. 1910. Do SS eee oe a ad Le ed eee 1913] EAST—CROSSES OF NICOTIANA 183 recombination of cumulative unit factors that do not show the phenomenon of dominance. The frequency distribution of the F, generation in these cases is not (-+})", as it is where dominance is complete, but is ($-+4)*", because a factor in the heterozygous condition is to be regarded as producing one-half the effect that it produces when in the homozygous condition. Regarding this expression as proper for the moment, let us examine the F, frequency distribution for length of corolla with the idea of assigning a definite number for in the expression (5 a 1a If n is made equal to 3, (ies by the theory the F, distribution should have seven classes with the frequencies 1-6-15-70-15~0-1 per 64 individuals. For 828 individuals, the grandparental sizes should each be recovered (828-64) =13.0—) nearly thirteen times. This was not the case in the actual distribution. If m is made equal to 5, the F. distribution should have eleven classes with the frequencies I-I0-45-120-210-252-210-120-45-10-1 per 1024 individuals. With 828 individuals the grandparental ‘classes should each be recovered only 0.8 times; in fact, a majority of populations of this size would not show the grandparental classes at all. This also is not the condition that was actually found. There is left only the possibility of making equal to 4. When this is done the F: distribution for 256 individuals—the smallest number in which a representative of each class may be found— and for 828 individuals is as follows: 1- 8- 2 56 7o 56- 28- & 1b 3.2-25.9-90.6—-181 . 1-226. 4-181 . 1-90. 6-25 .9-3.2 This calculation points to the recovery of each grandparent about 3 times in the F, population under observation. Reference to table I shows that the figures actually obtained agree rather closely with this observation. But table I also shows another important fact. The arbitrary classes used had a range of 5 mm., which makes 1 3 classes necessary to express the F, generation. 184 BOTANICAL GAZETTE [MARCH This class size was adopted in accordance with the usual biomet- rical procedure, the variations in the small parent (314) being included in only 3 classes. But when this is done, the F, dis- tribution is decidedly skew. The theoretical mode is along about the fourth or fifth class instead of the central class. What is the reason for the production of this type of curve? There must bea reason, and it seems to me that this reason must be biological and not a mathematical transnomination, as have been all the bio- metrical analyses of skew curves. The matter appears clear in the light of the following interpretation. In ordinary statistical work, one produces a frequency dis- tribution by throwing his tabular entries into arbitrary classes of equal size. By this procedure he has in all probability distorted their relationship. This fact is partially recognized by using the coefficient of variability instead of the standard deviation as a measure of variation. Unfortunately, it is usually said that the coefficient of variability is used instead of the standard deviation because it is an abstract measure and pounds can be compared with inches, etc. Standard deviations in the same concrete terms are usually thought comparable with each other. But is this true? Apply the rule to the data in-tables I and II. The range of length of corolla of N. forgetiana (314) is 3 classes, the standard deviation is 2.27 0.08 mm., and the coefficient of variability is 8.86 +0. 33 per cent. The range of N. alata grandiflora (321) is 6 classes, its standard deviation is 5.38+0.20 mm., and its coefficient of vari- ability is 6.82+0.25 per cent. Paiecing standard deviations, N. alata grandiflora is twice as variable as N. forgetiana. Com- paring coefficients of variability, which being functions of the mean give weight to the size of the mean, the large-flowered type (321) is less variable than the small-flowered type (314). Let us now look at the matter from an ordinary common-sense biological standpoint. These pure line populations may be con- sidered as composed of near-homozygous individuals. The range of variability shown is therefore almost wholly due to environ- ment. In general, NV. alata grandiflora has a corolla more than twice as long as NV. forgetiana. Is it not reasonable to suppose that the unit change effected by environment and expressed as 4 1913] EAST—CROSSES OF NICOTIANA 185 fluctuation is proportional to the size of the individual? Is it not true that favorable circumstances which force the corollas of N. forgetiana to become 5 mm. longer than usual will produce a 10 mm. change in WN. alata grandiflora? If this is the correct way of looking at these two cases, then it is assuredly an error to plot the F, distribution—which includes both grandparental sizes—in classes of equal size. Assuming that our hypothetical size factors affect the individual as growth forces, it seems probable that they are not only cumulative but accelerative. Roughly one might imagine the effect on the individual to be something like a constant percentage. I do not believe these cases of size inheritance can be analyzed into their component factors and these factors given their proper weight (using the word factor in the general sense of elements or causes that produce a result) sufficiently well to give a precise value to the character determiners themselves. On the other hand, it is interesting to see just what is necessary in the way of class range to bring our F, corolla distribution to the normal distribution for four factors (n=4). Fortunately the corolla sizes were taken by millimeters, so this can be done. First I have smoothed the figures according to the regular method. The distribution in one- - millimeter classes i is then as follows (table IV, p. 186). Suppose now we begin at 24 mm. and take for this class a range of 4mm. Then let us increase our class range 1 mm. each time. This gives a simple arithmetical progression with an advancing difference of the second order, that is, the differences between the class ranges are constant. Compare the frequency distribution thus obtained with the expansion of (3-+3)*" where m is equal to 4. This is done in table V, with an agreement among the figures that is very remarkable. If I were a biometrician, I probably could show that this agreement could not be due to chance—since by chance it could only occur once in some hundreds of thousands of times—and must therefore have some great significance. I should prefer to believe that I happened by chance upon a series of class ranges that fitted the normal frequency theory. But it must be emphasized that it was a constant increase in class range that produced the normal curve from the distorted skew curve. 186 ; BOTANICAL GAZETTE [MARCH Perhaps no two actual frequency distributions would be alike in thus yielding to a simple arithmetical correction. Such a correc- tion is probably fallacious in its simplicity. It serves our purpose, TABLE IV MEASUREMENTS OF LENGTH OF COROLLA IN F, POPULATION OF CROSS BETWEEN Nicotiana forgetiana AND N. alata grandiflora 24 ° 45 25 66 12 25 2 46 28 67 10 26 2 47 29 68 7 27 2 48 28 09 7 28 I 49 28 70 6 _ 29 3 50 26 71 6 30 5 51 28 72 5 31 8 52 23 73 6 32 10 53 20 74 4 33 Ir 54 20 75 S 34 15 55 19 76 2 35 13 56 22 17 2 36 18 57 22 78 ° 37 18 58 22 9 I 38 19 59 26 50 2 39 26 60 21 I 2 28 61 22 2 I 41 33 62 15 3 ° 42 24 63 15 4 I 43 23 64 14 5 ° 24 65 12 6 Ir TABLE V COMPARISON BETWEEN THE THEORETICAL FREQUENCY DISTRIBUTION FOR FOUR FACTORS THE ACTUAL FREQUENCY DISTRIBUTION RESULTING WHEN CLASSES WITH A CERTAIN CONSTANTLY INCREASING RANGE ARE USED Class limits 24-27 | 28-32 | 33-38 | 30-45 | 46-53 | s4-62 | 63-72 | 73-83 | 84-95 Class range...... 4 5 6 7 8 9 10 II 12 Frequency. 5.2... 6 27 04 |183 |210° |189 04 23 3 Calculated fre- quency for 828 individuals for ($+4)8........ 3.2 | 25.9 | 90.6 |181.1 |264.4 |18r.1 | 90.6 | 25.9 | 3-? however, if it calls attention to the manifest error of expressing a wide range of biological variation by a frequency polygon of equal size classes. 1913] EAST—CROSSES OF NICOTIANA 187 Summary Concluding, the following points may be again emphasized: | 1. The inheritance of size complexes is so intricate that it is 9 ......% | necessary to simplify an experiment upon them in every possible. manner. The material used in this investigation, Nicotiana for- okie pou getiana Hort. Sand. and N. alata grandiflora Comes, lacks three of “~* all aLianks atuh, . the complicating features that usually ensnarl such work. They *-&: are almost always naturally self-fertilized, and through numerous generations of self-fertilization have become automatically as homozygous in their characters as may be expected in Sas _reproduce sexually. | Their fecundity is so great that practically any quantity of F, individuals can be produced from a single F, plant. A plant character was investigated upon which the effect of environment is so small as to be negligible, namely corolla size. 2. These self= species, which are perfectly fertile imier se, gave self-sterile progeny. This fact did not affect the production of an F, generation, as the F, plants from homozygous parents are alike in gametic constitution, and these were perfectly fertile inter se. 3. N. forgetiana with a mean corolla length of 25.6 mm. crossed with WN. alata grandiflora with a mean corolla length of 78.8 mm. resulted in an intermediate F, generation with a mean variability of 44.3 mm. 4. The variability of the F, generation was very small, being about the same as that of the remarkably constant parental species. The F, generation, on the contrary, was very variable and both grandparental types were reproduced. 5. It is shown that the F, generation is what would be expected if the difference in corolla length shown by these two species were represented by the segregation and recombination of four cumu- lative but independent pairs of unit factors, dominance being absent. 6. The coincidence of theory and result is as great in this case as it is in qualitative characters of like complexity. If the Mendelian notation is useful to describe complex qualitative in- heritance, it is similarly useful in describing the inheritance of quantitative characters. 188 BOTANICAL GAZETTE [MARCH 7. Length of style and of filament are perfectly correlated with corolla length. 8. Breadth of corolla shows an average correlation with length of corolla equal to 61 per cent. g. The frequency distribution of corolla length for the F, generation is positively skew. It is pointed out that the range of fluctuations of corolla length in the two pure species is twice as great in the one of larger size than in the other. Classes of equal size in frequency distributions of great variability appear to be arbitrary and improper, if size factors are assumed to be dynamic factors with fluctuations roughly expressed by the term growth force. To show this accelerative action, the class ranges must gradually increase as the size (that is, the number of factors) increases. It is shown that the distribution under discussion will be changed from skew to normal if a simple arithmetical increase in the size of the classes is made. Bussey INSTITUTION - Boston, Mass. " EXPLANATION OF PLATES PLATE Vi At the left, a young flowering plant of Nicotiana alata Link and Otto, vat- grandiflora Comes; at the right, a young flowering plant of NV. forgetiana Hort. Sand. PLATE VII A mature plant of the first hybrid generation of a cross between N. a getiana and N. alata grandiflora. > PLATE VIII Figs. I, 2, and 3, upper, Rete ea lower leaves of a mature plant of usaiela . PLATE: 1X At the left, a flower of NV. alata grandiflora; at the right, a flower of V- forgetiana; between them are extreme F, segregates in length and spread of corolla; taken on the same plate, three-fourths natural size. PLATE X Fig. 1, NV. alata grandiflora; fig. 2, N. forgetiana; fig. 3, cross between N. forgetiana a N. alata grandiflora, F; generation; the remaining figures are F, segregates; all figures are three-fourths natural size. VNVILOOIN 4° LSVa IA ALVId AT ‘ALLIAZVI TWOINVLOG VNVILOOIN YO LSVH IIA ALVId AT ‘ALLAZVD TVIINVIOT BOTANICAL GAZETTE, LV PLATE Vill EAST on NICOTIANA VNVILODO!I XI ALVId AT GALLAZVI TWIINVLOG BOTANICAL GAZETTE, LV EAST on NICOTIANA LS De te he ee re! Teg gam TG an jas Se ON eae ade 9 es Se es ot 0 SENT Rn he ers Sgt ok Tee ei 4. THE CLIMAX FOREST OF ISLE ROYALE, LAKE SUPERIOR, AND ITS DEVELOPMENT. III. CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 165 WILLIAM S. COOPER (WITH TWENTY-FIVE FIGURES) The hydrarch successions The bog succession I. Physiographic development of the bog habitat At the commencement of the glacial period the topography and the drainage system of what is now Isle Royale were very similar to those of today, except that lakes and swamps were few or absent. This topography was but slightly modified by the invasion of the ice, and the most important change effected by glacial erosion was the excavation of rock basins in the preglacial valleys. Since the retreat of the ice the gradual emergence of the island from the waters of the lake has taken place. In some cases inclosed basins appeared above the surface ready made; in others they were pro- duced by wave-built bars thrown across the mouths of harbors or both ends of channels during pauses in the retreat of the waters. By continued emergence some of these rock basins and cut-off bays came to occupy positions far in the interior of the island. The tilting which followed the Lake Nipissing stage must have had some effect upon the island lakes thus formed. It may have brought about the partial draining of some, the enlargement and perhaps even origination of others, and occasional shifting of outlets; in all cases it must have produced a tendency toward migration to the southwest. The physiographic development of the bog habitat thus includes as a rule two periods: first, the channel-bay stage, and second, the lake stage. Numerous localities that illustrate the process may be seen today, especially at the northeast end of the island. Duncan 189] [Botanical Gazette, vol. 55 Igo BOTANICAL GAZETTE [MARCH Bay would become a lake if the water level should sink 5-6 m.; Pickerel Cove is a similar case; and the inland portion of Rock Harbor is nearly closed at its narrowest point by a sand bar that has been built almost to the surface. Several of the lakes of Isle Royale are of respectable size. Siskowit Lake, the largest, is more than 10 km. long and 2.5 km. wide (fig. 31). The majority are small, many being mere ponds. All the lakes, and the harbors as well, are tending toward extinction through down-cutting of outlets, sedimentation, and vegetation. Down-cutting of outlets has as yet accomplished very agi Fic. 31.—Siskowit Lake: the largest of the Isle Royale lakes little. The large lakes like Siskowit are being filled by sedimenta- tion with extreme slowness, because of the small size of the streams, their slight gradient, and the thick covering of vegetation which almost inhibits erosion of the land surfaces. It is impossible for bog vegetation to obtain a foothold in the large lake basins except here and there in very sheltered spots, because of vigorous wave and ice action (HoLT 33, p. 218). They will therefore remain much as they are for a long time. In the small lakes, on the other hand, where wave and ice action are not severe, invasion by bog vegetation is in active progress. 1913] COOPER—ISLE ROYALE : Igl II. Vegetational development in the bog habitat — 1. Channel-bay stage Even as early as the channel-bay stage we find the beginnings of the vegetational history of the bog habitat. If the body of water be large or subject to considerable wave and current action, plant life is practically absent. In sheltered places, however, there lives a plant society, sparse but characteristic. The com- monest species is [soetes macrospora Dur. (quillwort), growing entirely submerged at a depth of o.3-1m. in the silty sediment that covers the bottom. Jsoetes here attains an unusual size, the crowns being frequently 5 cm. and more in diameter. With it grow occasional plants of Chara (stonewort), Ranunculus aquatilis L. var. capillaceus DC (water crowfoot), Potamogeton perfoliatus L. and other spp. (pondweeds). On shoals and along the reefs at the _ ends of the narrow islands and points are frequent clumps of sedges: Carex aquatilis Wahlenb., C. stricta Lam., C. lenticularis Michx. 2. Lake stage The lake stage is considered as extending from the first complete inclosure of the body of water to the time when the bog’ vegetation has brought about its extinction. During this physiographic stage all the vegetational stages of the bog succession usually appear in their accustomed order. The aquatics are already present and the sedge society has often made a slight beginning. The latter now develops with rapidity, especially in the smaller lakes, and is followed in turn by the sphagnum-shrub society and the bog forest. ; a) Peat formation Peat formation in the northern and southern peninsulas of Michigan has been described by TRANSEAU (56) and by Davis (19). The bogs which Davis studied, especially in the Upper Peninsula, are very similar to those of Isle Royale, and this author shows that the sedge mat is the most important agent in the forma- tion of the peat. Lack of time and facilities prevented a study of the basin-filling process upon Isle Royale, but it is certain that the bulk of the peat is deposited through the formation and sinking of the sedge mat and the accumulation of finely divided material Ig2 BOTANICAL GAZETTE [MARCH dropped from it. A subordinate amount is formed from the remains of the aquatic vegetation preceding the sedges in the invasion of the basins and from the shrub-sphagnum vegetation which follows them. b) Illustrative localities To illustrate the course of the bog succession upon Isle Royale several representative localities will be briefly described. Amygda- loid Lake shows the bog plants gaining their first foothold along the shore; the two ponds near Tobin’s Harbor have been partially Fic. 32.—Amygdaloid Lake: in the eon a thick growth of Menyanthes and Listuele thyrsiflora; farther out, Nymphaea adve covered and filled; and the basin on Raspberry Island contains a completely covered bog. Amygdaloid Island lies parallel to the northwest shore of isle Roy ale and is formed by two partially submerged ridges of the usual kind. Between the ridges is an inclosed basin which contains a narrow lake, 100m. wide at the most, but 1.2km.long. It should be noted that Amygdaloid Lake is identically like the basin on Raspberry Island, to be described later, in situation and physiographic development. For some reason its history has not progressed so far, although both are at 1913] COOPER—ISLE ROYALE 193 the present lake level. It may be that the basin has been more recently shut off from Lake Superior than that on Raspberry Island, and also the depression is larger and doubtless deeper. The climax forest descends to the edge of the interior lake, except for an occasional short strip of stony or sandy beach. At the southwest end there is a considerable amount of bog vegetation, growing in water a few centimeters deep and underlain by 2 m. of soft mud containing much organic material. The principal aquatic is Nymphaea advena Ait. (yellow pond lily). There is next a zone of amphibious plants dominated by Menyanthes trifoliata L. (buckbean), which is accompanied by Lysimachia thyrsiflora L. (bog loosestrife) and a few other species. As will be noted later, Menyanthes is frequently an important mat-former. Through the middle of this zone winds a narrow streamlike ribbon of water, probably the last remnant of a sluggish outlet. Back of the Menyanthes zone and filling the continuation of the basin for o. 5 km. is the bog forest, composed of Larix and Picea mariana, with Alnus incana (L.) Moench (hoary alder) in front. The arrangement of the vegetation here illustrates a feature characteristic of the bog-filled depressions of Isle Royale. On account of the elongated form of the basins, the building out of the bog vegetation goes on much more rapidly at the ends of the lakes than along their sides, because of gentler slope. Theoretically, also, it should build out faster on the northwest side than on the southeast, since by reason of the rock structure the former slope is normally gentler than the latter. In a few cases notable difference was seen in the width of the sedge mat corresponding to the difference in slope, but usually the width of the zone on the two sides was about the same. Probably talus deposits, slope wash, and sediments of various kinds tend to lessen the slope of the southeast side, making it more or less equal to that of the other. It has been stated that along the greater part of the lake shore the climax forest descends to the water’s edge. At one point (a sandy stretch) bog vegetation was found to be obtaining its first foothold. Farthest out were scattering plants of Nymphaea advena. Close to shore grew scattered stools of Carex filiformis L. (bog sedge) and plants of Eleocharis palustris (L.) R. & S. (creeping 194 BOTANICAL GAZETTE [MARCH spike-rush) and Eguisetum fluviatile L. (scouring rush). Here we have the very beginning of the sedge mat, Carex filiformis being the most important mat-builder in most of the Isle Royale bogs. Next came a nearly bare level sandy shore 1-3 m. wide, at the upper edge of which began a second belt of bog vegetation. A line of depauperate Menyanthes with rootstocks creeping out over the gravel formed the lowest portion. It is probable that there has been a slight recent change of level in Amygdaloid Lake and that the Menyanthes marks the height of the former water surface. Above the Menyanthes was an area peopled by a number of species belong- ing partly to the bog forest and partly to the climax forest. These are as follows: Lycopodium annotinum L. (stiff club moss), Smila- cina trifolia (L.) Desf. (three-leaved Solomon’s seal), Chiogenes hispidula (L.) T. & G. (snowberry), Symplocarpus foetidus (L.) Nutt. (skunk cabbage), Coptis trifolia (L.) Salisb. (goldthread), Linnaea borealis L. var. americana (Forbes) Rehder (twin-flower), Pyrola secunda L. (shin leaf), Cornus canadensis L. (bunch-berry), Trientalis americana (Pers.) Pursh (star-flower), Maianthemum canadense Desf. (two-leaved Solomon’s seal), Mitella nuda L. (mitrewort), Moneses uniflora (L.) Gray (one-flowered wintergreen). This low vegetation was nearly smothered by a dense growth of sphagnum, much of it very young. The Lycopodium, which was the most abundant species of the list given above, showed only the tips of its branches except along the edge of the sphagnum mass, where thick clusters of new shoots projected from beneath the moss. The plants of Coptis were many of them buried up to the leaves. Upon the surface of the sphagnum grew Drosera rotundi- folia L. (sundew) and Linnaea. A low beach ridge supported the most luxuriant sphagnum growth, which was occasionally as much as 0.3m. deep, especially where it surrounded shrubs and tall grasses. Calamagrostis canadensis (Michx.) Beauv., Agrostis hyema- lis (Walt.) BSP, Iris versicolor L., Campanula uliginosa Rydb. (bog bell-flower) grew here, and also Alnus incana (L.) Moench. (hoary alder). It is noteworthy that everywhere along the shore, except where the sphagnum has become established, Alnus crispa rather than A. incana forms the forest margin. In and around the sphagnum grew a few bog trees, Larix 1-3 m. in height, and young 1913] COOPER—ISLE ROYALE 195 Picea mariana and Thuja; and back of these was a narrow band of bog forest, hardly more than a single line of large trees, Larix and Thwa, with much young Abies and Betula, and the usual herbace- ous growth of such a habitat, practically the list given above. The sphagnum was evidently spreading from the ridge both toward the water and into this area of bog forest. Behind all was the climax forest of balsam, spruce, and birch. It is evident from the foregoing description that at this locality we have in embryo every society or zone of the bog succession, Fic. 33.—Sucker Lake: aquatics; sedge zone of peti petes ees with M en sis: at the left a narrow zone of shrubs and a thin line of t acks border- ing the climax forest; a thick growth of bog trees at the end of the Sati Gane, from the aquatics through the sedge mat (represented by the stools of Carex and its companions), the sphagnum-shrub zone supporting the nascent bog forest, to the mature bog forest invaded y the climax trees; and all in the space of only rom. It is thus demonstrated that all the zones may begin their development at approximately the same time. Sucker Lake (fig. 33; Sec. 34, T.67 N., R. 33 W.).—The develop- ment of the bog vegetation is here far advanced. A wide zone of aquatics nearly surrounds the small area of open water, and this in turn is surrounded on three sides by a broad sedge mat made up of 196 BOTANICAL GAZETTE [MARCH Carex filiformis L., C. limosa L., C. chordorrhiza L. f., C. poly Schkuhr, C. ldiastersa Micix.. and C. livida (Wahlenb.) Willd Along the outer edge of the mat and almost forming a zone by itself is a fringe of Menyanthes, its thick rootstocks closely inter- twined. The shrub zone, dominantly Myrica Gale L. (sweet gale), is poorly developed, and sphagnum is nearly absent, only a sparse growth being seen and this nearly choked by the luxuriant sedges. Along much of the southeast shore the sedge mat is absent and the shrubs are the marginal vegetation. Here Chamaedaphne and Fic. 34.—Pond near Tobin’s Harbor in Sec. 5, T. 66 N., R. 33 W.: aquatics occupying center; sedge zone of Carex filiformis ay in the background hoary alder and tamaracks bordering the climax forest. Andromeda grow actually in the water. Davis (19) has noted this replacement of the sedge zone by a shrub mat as a very common occurrence in the bogs of the northern peninsula of Michigan, but it is rare on Isle Royale. The bog forest at Sucker Lake is a mere line of tamaracks along the sides of the basin, but is well developed at both ends, where great stretches of the narrow depression have been converted into a forested valley. Sucker Lake is the last remnant of a body of water that was once very similar to the Rock Harbor of today. 1913] COOPER—ISLE ROYALE 197 Pond near Tobin’s Harbor (fig. 34; Sec. 5, T. 66 N., R. 33 W.).— This locality is closely similar to the last and occupies the same type of basin, with considerable bog forest at both ends. Develop- ment has proceeded one step farther, there being no open water, and the aquatics thus occupy the center. The sedge zone is con- tinuous and everywhere equally developed. Soundings through the mat showed that the slopes of the bottom on the northwest and southeast sides are not notably different. Carex filiformis is the principal mat-former. The other species contributing are Carex Fic. 35.—Same locality as fig. 34: Scirpus hudsonianus prominent in the sedge zone; salar of shrubs, Alnus incana surrounded by Chamaedaphne; a thick growth of bog trees at the end of the bas limosa L., C. chordorrhiza L. f., C. Michauxiana Boechl., C. livida (Wahlenb.) Willd., and C. polygama Schkuhr. The principal bog herbs accompanying the sedges are as follows: Menyanthes trifoliata L. (buckbean), Potentilla palustris (L.) Scop. (marsh cinquefoil), Vaccinium Oxycoccos L. var. intermedium Gray (cranberry), Rhynchospora alba (L.) Vahl (white beak-rush), Cicuta bulbifera L. (water hemlock), Hypericum virginicum L. (marsh St. Johnswort), Scirpus hudsonianus (Michx.) Fernald (alpine cotton-grass), Epilobium palustre L. (marsh willow-herb), Scutellaria galericulata 198 "BOTANICAL GAZETTE [MARCH L. (skull-cap), Lysimachia terrestris (L.) BSP (loosestrife), Cam- panula uliginosa Rydb. (bog bell-flower), Galium Claytoni Michx. (bedstraw), Lycopus uniflorus Michx. (bugle-weed), Sarracenia purpurea L. (pitcher-plant), Drosera rotundifolia L. (round-leaved sundew), Iris versicolor L., Arethusa bulbosa L., Spiranthes Roman- zofiana Cham. (lady’s tresses), Habenaria dilatata (Pursh) Gray (white bog orchis), H. psycodes (L.) Sw. (purple-fringed orchis). Sphagnum is rare. The shrub zone is better developed than at Sucker Lake and includes two subzones: the outer, in which Chamaedaphne calyculata (L.) Moench is dominant and accom- panied by Andromeda glaucophylla Link and Salix pedicellaris Pursh; the inner, of Alnus incana (L.) Moench. Advance islands of shrubs are scattered here and there over the sedge mat, the outermost being composed of Chamaedaphne, and the inner of a nucleus of Alnus incana surrounded by a circular zone of Chamae- daphne (fig. 35). Seedlings of tamarack are frequent in these colonies. The subzone of Alnus incana fringes the outer edge of the bog forest, which here as usual is a mere line along the sides, but broader at the ends. The bog tree is the tamarack. 3. Open bog stage: Raspberry Island bog Raspberry Island is one of the row that bounds Rock Harbor on the southeast, and is next in line to Smithwick Island, studied in connection with the climax forest. Its upland forest cover was originally like that of Smithwick, but unfortunately this has been largely fire-swept, the bog area, however, having escaped unharmed. The island consists of two parallel ridges of the typical Isle Royale kind, bounding a narrow depression, closed at both ends by beach ridges, which contains the bog area. The outer ridge is the more massive of the two and makes the bulk of the island, while the inner is only half as long. Both reach an elevation of about rom. The island has emerged from the lake in comparatively recent time, and its history has been a simple one; moreover it is in all essentials the history of Isle Royale itself on a small scale. When the lake level was 3 m. higher than now there was a channel over the site of the bog area. At this time currents and waves were doubtless at work building bars across the channel mouths. With continued sub- 1913] COOPER—ISLE ROYALE 199 sidence of the lake level the bar at the exposed southwest end emerged and became a beach connecting the two ridges, which now inclosed a sheltered bay. Into this con- siderable sediment was still being carried by waves and currents. As the lake level continued to fall, the more slowly building bar across the sheltered northeast end of the harbor emerged, and the bay was now an inland lake. Itis probable that the height of both beaches has been in- creased since their emergence : through the agency of storm a waves. The physiographic history of the habitat is thus concluded. Its likeness to Amygdaloid Island will be at - once evident. At Amygdaloid 4 Lake we find the beginnings of the bog vegetation; Rasp- berry Island shows its culmi- nation, in the sense that at this stage the open water has disappeared, and all the bog societies are present and at 2 their best development. The : further history will record the progressive extinction of these societies by centripetal invasion. The relations of the zones _ to each other are shown in the 1.51. Contour, Interval SO Meters um-Ledum invading er orest ore: og rrMarginal Zone 3B a Prete Gee + eee eS nt ¥uiv vy My. (Aa bid a SES ee oy ¥ v, Fic. 36.—Map of Raspberry Island (upper left-hand corner) and the bog area on a larger scale: the location of quadrat 9 is shown 200 BOTANICAL GAZETTE [MARCH map (fig. 36) and in the general view (fig. 37). Certain features of the succession were so well developed in this bog that they must have a place in this account. The sedge mat is composed almost entirely of Carex limosa L. (mud sedge) (fig. 38). Occasional bare muddy spots are nearly free of sedge, but support a scattered growth of Menyanthes and Drosera anglica Huds. (narrow-leaved sundew). These appear to represent the youngest stage now existing in this habitat. Fic. 37.—Raspberry Island bog: general view; sedge zone of Carex limosa type in the scensolitide the sphagnum-shrub society occupies most of the view; young bog trees as pioneers of the forest; black spruce prominent in the bog forest. a) The sphagnum and its relations Particular attention was given to the sphagnum, which is very luxuriant in this bog; especially to its point of origin, the conditions governing its spread, and its relations to companion species. The first point to be noted is that the sphagnum is a superficial layer supported upon the sedge mat, and thus does not contribute in any large degree to peat formation. This feature has been noted by Hott (33) for the Isle Royale bogs, and by TRANSEAU (56) and Davis (19) for the northern and southern peninsulas of Michigan. 1913] COOPER—ISLE ROYALE 201 The next important fact is that the sphagnum does not make its first growth at the extreme edge of the bog area and from here works its way centerward only. On the contrary, it begins its growth some distance within the bog margin and works both ways; very slowly toward the margin, faster toward the center. Proof of this course of events is seen in the entire absence of sphagnum from the marginal zone, except in certain parts where it is mani- festly a recent invader. Soil samples taken at various depths in Fic. 38.—Sedge zone of Carex limosa type; Raspberry Island the marginal zone, examined microscopically, failed to show the slightest trace of sphagnum remains, although these are long pre- served and readily recognized. Another proof is found in the form of the sphagnum accumulation, which is that of a ridge parallel to the bog margin and at a somewhat constant distance from it. This ridge usually has its greatest thickness close to the outer (marginal) side, doubtless marking here the region of first growth. It will be remembered too that in the primitive stage observed at Amygdaloid Lake the sphagnum was seen to be spreading both ways. The face toward the bog margin (on Raspberry Island) is usually rather abrupt, forming a prominent wall which bounds the marginal zone. Occasionally a thin layer of sphagnum is found 202 BOTANICAL GAZETTE [MARCH to be invading the latter area. In the opposite direction (center- ward) the sphagnum decreases gradually in thickness, and at its edge invasion of the sedge zone is actively taking place. Fig. 39, drawn to scale, is a typical bog section. The form of the ridge is shown and also the depth at various points. The high projection upon the sphagnum mass is a hummock, the true marginal face being at the right. A tongue of the moss is seen invading the marginal zone. Below the line which is drawn as marking the base of the sphagnum the soil is black peat containing little that is recognizable even with a microscope. At several places, however, sphagnum fragments were recognized in various degrees of abun- dance some centimeters below the line indicated. These were a b c d e LLL» Me — eB Dore Laie ho 7 Peat d Bed Rock TWN ~ oes es Fic. 39.—Section through fiokoky Island bog: a, Sphagnum-Chamaedaphne; b, Sphagnum-Ledum; c, Sphagnum invading marginal trench; d, marginal trench; ¢, upland; 1, sedge zone; 2, Calliergon Schreberi; 3, Calliergon Schreberi (fossils) ; 4, Carex trisperma and Hylocomium proliferum; 5, Hylocomium proliferum; 6, 7; Drepanocladus vernicosus (?) (fossils). probably washed down from above, since this line certainly indi- cates the plane at which the growth began. The development of the sphagnum has not made uninterrupted progress, for at 3 on the section a stratum was found which con- tained abundant fragments of Calliergon Schreberi, and at 6 and 7 remains of Drepanocladus vernicosus (Lindb.) Warnst. were discovered. These two species evidently obtained a foothold upon the surface of the sphagnum and for a time arrested its growth over certain areas. The latter again gained the upper hand and buried the invaders. The zone included between the sphagnum and the slopes of the ee commonly takes the form of a circular trench. This ‘marginal trench” is a widespread feature of bogs, and various 1913] COOPER—ISLE ROYALE 203 causes for its occurrence have been suggested by MACMILLAN (38), SHaw (52), Davis (19), and ATKINSON (5). None of these explanations could be applied with certainty to the phenomenon as observed upon Isle Royale, but that offered by ATKINSON seemed most plausible, that is, that during the early development of the sedge mat the sphagnum was excluded by the shade cast by the near-by forest growth. Only after the bog substratum had built out beyond the shaded area did the moss become established upon it. < at i 33 Fic. 40.—Tension zone between sedge and sphagnum-shrub societies: Carex limosa ay Chunanedatinie keep pace with the growth of the sphagnum by upward elongation; Raspberry Island. The third point to be considered is the manner of invasion by the sphagnum, including its relations to the sedges and other plants which it finally replaces, and to the shrubs which accompany or follow it. The sphagnum area spreads marginally, and at the same time colonies of young plants originate among the sedges in advance of the main mass. Several such colonies are shown on the map (fig. 36). By the coalescence of these and the solid mass behind, the sphagnum zone extends itself at the expense of the sedge mat. Certain plants of the sedge zone persist for some time after the sphagnum has gained control. They do this by a process of upward 204 BOTANICAL GAZETTE [MARCH elongation, keeping pace in this way with the building up of the moss. Carex limosa itself survives for a considerable time. Stalks of this species apparently growing on the sphagnum can always be traced down to the stratum beneath, and the buried portions are found to be covered with dead remnants of leaves (fig. 40). Men- yanthes manages to persist for a time in a similar way. Sar- racenia, which as a rule precedes the sphagnum, makes use of the same method in an endeavor to hold its own, but is less successful Fic. 41.—Zonal arrangement of bog shrubs: Andromeda in the foreground, mainly upon the sedge mat; oss a ground at the right) mainly upon a mound of sphagnum; Raspberry Is and is soon buried. Certain of the bog shrubs belong to the same class. Chamaedaphne, Andromeda, and Salix pedicellaris usually precede the sphagnum. When the moss starts its growth in the vicinity of these plants it builds up rapidly around their stems, forming the hummocks that are so characteristic of sphagnum bogs. Of the three shrubs, Chamaedaphne has the greatest power of hold- ing its own against the smothering tendency of the moss (fig. 40); the willow is next; while Andromeda soon succumbs. The two important bog shrubs, Andromeda and Chamaedaphne, are zonally arranged (fig. 41). Andromeda grows freely on the sedge mat, especially in the wetter parts, is. most abundant just at the a 1913] COOPER—ISLE ROYALE 205 edge of the sphagnum, and occurs to a limited extent some distance back in the moss. Chamaedaphne is also found commonly upon the sedge mat, but inhabits the drier portions. In the sphagnum area it is abundant and over a wide belt almost the only shrub, extending back until it meets the zone where Ledum groenlandicum is the dominant species. Relative ability to withstand extreme wet bog soil conditions determines this zonation at the beginning, but the sudden elimination of Andromeda, leaving Chamaedaphne in full control, is due principally to the smothering effect of the sphagnum, which the former shrub is unable to avoid. Chamaedaphne, on the other hand, is able to grow up with the moss indefinitely, and there- fore persists until the entrance of Ledwm introduces a new factor. It is not certain that Chamaedaphne does not sometimes germinate upon the surface of the sphagnum as well as upon the sedge mat, and thus in part maintain its dominance. It is certain, however, that Andromeda does not commonly do so, at least not successfully. Two other shrubs, Kalmia polifolia Wang (pale laurel) and Betula pumila L. (dwarf birch), occur in this and other bogs, but not in sufficient abundance for satisfactory study of their habits. Upon the surface of the sphagnum another group of species becomes established. Important among these are Carex pauciflora Lightf., Smilacina trifolia (L.) Desf. (three-leaved Solomon’s seal), Drosera rotundifolia L. (round-leaved sundew), Vaccinium Oxycoc- cos L. (small cranberry). All of these are able in greater or less degree to keep pace with’ the continued upward growth of the moss. Of far greater importance than these is Ledum groenlandicum Oeder (Labrador tea), which becomes established long after the other shrubs, indeed after all but Chamaedaphne, have disappeared. Ledum is almost invariably found to be related definitely to the sphagnum, its whole root system being contained within the mass. The growth that it forms is very dense (fig. 42), and as it is a taller shrub than Chamaedaphne it shades it severely, and thus finally causes its elimination. Its effect upon the sphagnum is similar. Because of the shade which Ledum produces and the considerable amount of waste which falls from it, the upward growth of the moss is gradually retarded and finally ceases altogether. 206 BOTANICAL GAZETTE [MARCH About this time or often before, young plants of other mosses more or less tolerant of shade become established upon the higher parts of the sphagnum mass. Polytrichum strictum Banks is the first arrival, and Aulacomnium palustre (L.) Schwaegr. and Callier- gon Schreberi (Willd.) Grout soon follow. These species form mats of continually increasing lateral extent, which put an effectual stop to further upward growth of sphagnum. Fic. 42.—Sphagnum-Ledum zone, the moss entirely concealed by the abundant growth of the latter; the edge of the bog forest in the background; Raspberry Island. b) Sphagnum invading the forest The fact has been mentioned that the sphagnum frequently spreads into the marginal zone as well as toward the center of the bog. In some places this invasion is so effective that the marginal zone is entirely obliterated. The moss does not always stop even here, but occasionally climbs entirely out of the bog, invading the climax forest. - A case of this kind was reported by Hott (33) from a locality near Siskowit Lake. A far more striking instance was discovered on Raspberry Island, near the northeast end of the bog (see map, fig. 36 and fig. 43). In a stretch of 50 m. along the margin the sphagnum had completely obliterated the marginal zone and had ascended the slope for varying distances. At the point of 1913) COOPER—ISLE ROYALE 207 farthest advance the mass had taken the form of a tongue 4m. wide, extending 10 m. from the true bog margin. The slope of its surface was about 25° and the highest point reached was 4.5 m. above the bog level. The sphagnum supported a luxuriant growth of Ledum which completely covered it. The unusual abundance of flowers in comparison with the plants of the bog itself was a noteworthy feature, as was also the comparatively small size of the leaves, both facts perhaps indicating somewhat hard con- ditions. Vaccinium Oxycoccos and Chiogenes hispidula were also abundant, and frequent small seedlings of birch, black spruce, and balsam were found. ©.6-1 m., and the edges were abrupt, but unfortunately the fire which destroyed the upland forest had encroached somewhat upon the bog vegetation, so that the marginal conditions could not be ascertained. 4. The bog forest and its development Although in the Raspberry 43: Bes the upland fo the view is Island locality the bog forest is taken from the bog, a oa the bog not so extensively developed as vegetation climbing the slope to a height i .5m.; berry Island. in other places, all the essential 4.5m; Baspoey = features are present. A series of four adjoining units was laid out, each 5 m. square, the whole forming a broad section cutting through all the societies from the sedge zone to the climax forest (quadrat 9, fig. 44). The manner of invasion of the sedge mat by the sphagnum is shown. To avoid confusion the distribution of the bog shrubs is indicated only in a general way. The trees of the various species, their locations, and ages are given in the manner made use beneath mas ISSN Sphagnum covered by humus 1 Pp Fic. 44.—Quadrat 9: Raspberry Island; for explanation of symbols see fig. 6 > E t NS. : BS NENIN d x SN ENYA VR YX AR 2 iG} >, AN RAN a ae SLABS 3 a am » GY 8 9 HES aa ee ena ee i 8 Ya e & KH & ® “a SORE o E i——j wo @ ———ji ow Oo craremeamis Seep SRC eo a por Pe 33 < | } ii MV—— iS : yf: onod Ly, BG Kd s tlh. bad AERA RAT TAA BY, a ee ik ao ———$ yee S9F re gvcoQ Cee sae ES _g@ od GtqY% oo fee ee ee i GARI BP II 28. ADMIRED EAA EET LTA us) et ae se ere Os eed oma, 8” coammacomenoumeaunagcesammeasnutesmaacarn (fe 4 LS — - AN SH opened ES 3 Abies balsamea A 14 Pyrus americana O ge 45-—Quadrat ro: bog near Park Place Hotel; for explanation of symbols see fig. 6, : but there is an excellent sample near the Park Place Hotel on Rock Harbor (Sec. 3, T. 66 N., R.33 W.). A quadrat in this locality was Studied and the results are shown in fig. 45. The oldest trees here were the three tamaracks, and they were also much the largest, being 2:75-5.25 dm. thick, and towering above their companions. 210 BOTANICAL GAZETTE [MARCH One of them was hollow, and all were more or less attacked by rot. The black spruces were found to be somewhat younger than the tamaracks. All were solid to the heart. The balsams, which were most numerous of the tree species, were of various ages from 47 to 161 years. No young balsams were present and the average age was very high (105 years). All showed signs of suppression dur- ing early life, probably due to shading by the faster growing bog trees. Within the last half- century the tops have reached the sunlight, and most of the balsams are now growing rapidly, though many are rotten hearted, as is common with this species. Two birches close to the quadrat, 1.5 dm. and 2.25 dm. in diame- ter, were found to be 62 and 69 years old respectively. No white spruce occurred in this locality, but the species is present in most areas of bog forest. A striking fact is the absence of reproduc- tion (fig. 46). No tree younger than 47 years was seen except a few one or two-year-old seed- lings of birch and mountain ash, Fic. 46.—Bog forest interior; locality : sad of quadrat 10: two large tamaracks in the which seem able to germinate background; black a balsam, and in deep shade but not to continue Alnus incana; ca of Carex trisperma growth. with Petasites and pc species; note ‘ pee b- absence of tree reproduction. The history of the area 1s pro ably as follows. The present generation of trees of both bog and climax type started during the period of open bog conditions, and growing up together produced so dense a shade as to inhibit the starting of new growth beneath them. Shelter from wind, due to the depression in which they grow, is doubtless the reason for the absence of windfalls and the unusually long life of the balsams. No reproduction will take 1913] COOPER—ISLE ROYALE 211 place until light is admitted to the forest floor by the destruction of some of the present generation. The characteristic bog forest shrubs are the alders. Alnus incana is found principally near the bogward edge, while Alnus crispa, belonging rather to the climax forest, inhabits the landward portions. In the lower vegetation mosses are most prominent both in quantity and variety; 22 species were taken from a single area of bog forest. Sphagnum spp. (relicts of the open bog stage), Cal- liergon Schreberi (Willd.) Grout, and Hylocomium proliferum (L.) Lindb. make up the bulk of the moss carpet. Sharing the forest floor with these is Carex trisperma Dewey which, accompanied by C. leptalea Wahlenb. and C. tenella Schkuhr, forms dense green mats of considerable size. In some places Lycopodium annotinum L. covers the ground, and in others there is a rank growth of Equisetum sylvaticum L. As minor features there are certain herbs that particularly characterize the bog forest. The most numerous are Habenaria obtusata (Pursh) Richards, Listera cordata (L.) R. Br., Smilacina trifolia (L.) Desf., Phegopteris Dryopteris (L.) Fée, Mitella nuda L., Coptis trifolia (L.) Salisb., Viola incognita Brainerd, Petasites palmatus (Ait.) Gray. The outstanding feature in the later part of the bog succession is the telescoping of stages. The sphagnum-shrub stage (when present) is hardly well established before the bog trees enter, and immediately following them or often actually with them come the climax trees. The reason for the early establishment of the latter is found in the likeness between the bog soils and those of the forested uplands. Those of the uplands are nearly as peaty in texture and properties as are those of the bogs. The causes of the peatiness of the upland soils trace back to other factors: low evaporation rate due to low temperatures; poor drainage because of solid rock substratum; and probable paucity of certain types of bacterial and fungal life. It follows, the two soils being much alike, that whatever trees can grow upon one may exist also upon the other. 5. Two types of bogs One of the numerous questions that could not be settled with entire satisfaction related to two fairly distinct types of bogs 212 BOTANICAL GAZETTE [MARCH involving somewhat different courses of succession. One had an abundant growth of sphagnum associated with much Ledum, and Picea mariana and Larix composing the bog forest. Those of the other type had little sphagnum, often practically none, and in these Ledum was rare or absent and Picea mariana almost never found, the bog trees being Larix and Thuja or Larix alone. The Raspberry Island bog is an excellent example of the first, which we may designate the sphagnum type; and Sucker Lake and the other pond near Tobin’s Harbor illustrate the second, or sedge type. In some cases these types may represent stages in the same succession, since sphagnum often does not become dominant until late in the history of a bog, and Ledum and Picea mariana follow the sphagnum, being dependent upon its presence. But it is certain that in many cases the Sphagnum-Ledum stage is entirely eliminated, and that when this happens Picea mariana does not appear, or holds a very subordinate place in the bog forest. The succession in such cases is as follows: (1) aquatics, (2) sedge mat, (3) shrub zone (Chamaedaphne, Andromeda, Alnus incana), (4) bog forest (Larix, often with Thuja). It is obvious that Sphagnum is the critical plant, since Leduwm and Picea mariana come later and only in bogs where the moss is abundant. Certain differences were noted in the conditions prevailing in the two types of bogs. It was universally true in the sphagnum bogs that were visited that the drainage was poor or lacking, the only water loss being due to very slow seepage and evaporation. Those of the sedge type on the contrary were usually well drained. There was often open water in the center, in which case the bog might well be at a stage earlier than that of sphagnum dominance. The covered bogs without much sphagnum usually possessed one or more small streams flowing in and an active outlet. In a few cases, however, the drainage was seemingly as poor as in the sphagnum bogs. As to the way in which these drainage differences affect the vegetation, if they do affect it, nothing was determined. Another fact was noted which quite certainly has a bearing upon the presence or absence of sphagnum. It was found that the sedge mat is composed of different species in the two types of bogs. In the sphagnum bogs Carex limosa, a low, soft, loosely growing 1913] COOPER—ISLE ROYALE 213 stoloniferous species, was usually the principal mat-former, and Menyanthes, with somewhat similar characteristics, was next in importance (compare figs. 33 and 38). In those of the sedge type, tall stiff sedges growing in dense clumps were most important, forming a thick meadow-like growth. Carex filiformis was the commonest species, but certain areas were found to be dominated by Scir- pus caespitosus L., the most densely tufted of all the sedges. These two kinds of sedge mat form very different substrata for the growth of the sphagnum. On account of the shortness and softness of Carex limosa the moss is never seriously shaded where that sedge is dominant, and it is able to grow over and around the Carex and Menyanthes plants with ease. The sedges in this case offer no effective resistance, and the sphagnum soon gains the ascendancy over them. Where Carex filiformis and plants of similar habit are the principal mat-formers the moss, if it starts among the closely placed clumps, ec hon a is shaded from the beginning. It portion of a bog near Siskowit Lake: cannot spread laterally among Larix and Alnus incana. the dense clusters of thick culms, and so remains in a half-smothered condition until exterminated through the advance of the shrubs and trees. The distribution of the two kinds of mat-forming plants still remains to be accounted for, and for this I have as yet no explanation. It is entirely possible that the type of sedge which gains the dominant place in a given bog may be determined merely by accidental causes. Occasionally the two phases may be seen in a single bog. For 214 BOTANICAL GAZETTE [MARCH instance, in a locality near Siskowit Lake (Sec. 32, T. 65 N., R. 35 W.) the central area (which is better drained than the rest, having a sluggish stream meandering through it) is of the sedge type. Some patches of bog forest near the stream are made up almost entirely of Larix, with much Alnus tncana as undergrowth. In the poorly drained areas near the margin the forest is pure Picea mariana, and the ground is carpeted with solid sphagnum covered with an abundant growth of Ledum. These two phases are shown in figs. 47 and 48. The delta swamp succession I. Extent and distribution The delta swamp succession comprises the successive stages of vegetational development which culminate in the establish- ment of the climax forest upon the deltas and alluvial plains of the streams. These societies do not occupy an extensive area in the aggregate, but they are ex- ceedingly interesting because of the close interdependence be- tween the successional and the Fic. 48.—Bog forest in poorly drained hvsi : Del slogr 1 sses. elta area; same locality as fig. 47; Picea paysiog aphic proce mariana, Ledum, and Sphagnum. swamps of various sizes are found at the heads of most of the bays, and are probably present also where streams of any size enter the larger lakes. Protection from the waves and currents of Lake Superior is naturally essential to their development. The localities studied were as follows: head of McCargoe’s Cove (Sec. 26, T. 66 N., R. 35 W.), Brady Cove (Sec. 18, T. 66 N., R. 35 W.), Duncan Bay (Sec. 6, T. 66 N., R. 33 W.), Lake Richie outlet at Chippewa Harbor (Sec. 18, T. 65 N., R. 34 W.), Hay Bay (Sec. me Mihi a= gt cae ae 1913] COOPER—ISLE ROYALE 215 24, T. 64 N., R. 37 W.), head of Siskowit Bay (Sec. 33, T. 64 N., R. 37 W.). II. Physiographic development of the habitat The history of the present deltas began with the initiation of stream activity as the island emerged from the lake. The amount of erosion accomplished by the streams of Isle Royale has been very slight. The sources of the materials transported by them have been principally two: the products of wave erosion left high and dry as the lake level sank, and weathered rock material, including some decomposed by organic agencies. Deposits were made at the mouths of the streams at all stages during the emergence of the island. As the lake surface sank these were transported to successively lower levels, and more materials were added. Of course some of the earlier deposits may have been so situated as to have escaped removal, but no such remnants have been reported. It is therefore probable that the present deltas include most of the materials that made up the earlier ones, brought down from level to level as the streams were repeatedly rejuvenated by successive sinkings of the lake surface. Delta building seems to have practically ceased, at least tempo- rarily, for three reasons: (1) th ilable | terial lated during the successive stages has all been brought down and deposited; (2) the complete forest covering of the uplands prac- tically inhibits further weathering and erosion, except what may be accomplished by the slow organic processes; (3) (applicable only to northeastward-flowing streams, which, however, are in the majority) tilting has taken place in the Lake Superior region since the formation of the Nipissing beach (Apams 4). At Isle Royale the elevation of this beach is about 18 m., and it rises northward to 27m. at Nipigon. This has decreased the gradient of north- eastward-flowing streams and thus has tended to reduce their erosive and transporting power. The result of these processes has been the formation of flat delta plains of gravel, sand, and silt at the heads of many of the harbors, with streams, practically currentless, meandering over them. Cut-and-fill and scour-and-fill are going on to some extent 216 BOTANICAL GAZETTE [MA RCH in these streams, which processes are due principally to alternating currents produced by seiche movements (ADAms 4) of the waters of LakeSuperior. The currents thus produced are quite considerable. At one moment there is a strong outward flow; a few minutes later the movement may be just as swift in the opposite direction. The effect of the seiche current is practically the same as that of an ordinary stream current. It undermines the bank in some places and deposits the eroded materials in others. On account of its alternating direction the gradational effects in a particular case cannot be so simply worked out, but judging from the relative positions of the eroding and depositing portions of the banks it seems probable, as one would naturally expect, that the outward current is the more effective. It is possible that occasional heavy rains may considerably increase the volume and velocity of the streams. The channels are not ordinarily sunk far into the sedi- mentary substratum. Their banks appear largely as_ vertical sections of the layer of plant growth which has spread over the delta plain. III. Vegetational development in the habitat The first vegetation upon the delta deposits enters when the water over them shallows sufficiently to permit the growth of aquatics of the pondweed type. Next come water lilies and rushes, and when the sediments accumulate until they reach nearly to the surface, sedges gain a foothold and soon form a mat. Up to this point the development has followed the same course as the bog succession. Important differences now appear. The sedge mat does not build out over the water, probably because of wave and ice action, since the bodies of water into which the streams flow are rather large and open. The sedge mat stage does not last long, but is very soon superseded by a dense growth of tall grasses, among which Calamagrostis canadensis (Michx.) Beauv. is by far the most important. It is this type of plant, growing in dense, closely placed stools, that forms the bulk of the stratum of plant remains which finally covers the plain. The grasses are followed by shrubs, and these by the swamp trees, which finally give way to the climax forest. 1913] COOPER—ISLE ROYALE 217 Among the delta swamps studied, the largest was at the head of McCargoe’s Cove. The alluvial flat was here 0.8 km. long by o.4km. wide. All the stages are here well developed except the swamp forest, which has been fire-swept. Part of the meadow-like marsh is shown in fig. 49, and a sketch map of the delta is given in g. 50. Farthest out, in water a meter and more deep, is a zone of Potamogeton perfoliatus L. Within this, in a few inches of water, grows Equisetum fluviatile L. Next comes the sedge mat, firmly grounded, with Carex filiformis as the principal species, accompanied chwewiiepe Fic. 49.—Delta swamp at the head of McCargoe’s Cove: sedge, grass, and shrub ielekien w are shown; the swamp forest has been burned. by bog herbs. The area dominated by Calamagrostis is the most extensive, and its level is perceptibly higher than that of the sedge zone. With Calamagrostis grow other herbaceous species, many of them tall, such as Thalictrum dasycarpum Fisch. and Lall. (tall meadow rue), Chelone glabra L. (turtle-head), Epilobium angusti- folium L. (fireweed), and Symplocarpus foetidus (L.) Nutt. (skunk cabbage). Stools and patches of Calamagrostis were seen as in- vaders of the sedge society, and occasional shrubs, pioneers of the next group, were scattered over the area occupied by the grass. Myrica Gale L. (sweet gale) is the first shrub to invade the 218 BOTANICAL GAZETTE [MARCH meadow swamp. It is followed by Alnus incana, which at first is pure, but farther back is found mixed with other shrubs: Cornus stolonifera Michx. (red osier dogwood) and Viburnum pauciflorum Raf. (high bush cranberry). With these come the invaders from the forest, Fraxinus nigra Marsh (black ash) being usually the first arrival. Burned stumps indicate that there was once an extensive development of swamp forest along the east side of the delta, in which Thuja was the important tree. The stream which winds through the swamp is 6-10 m. wide and o.3-1m. deep. Its channel is constantly changing by reason of its own undermining and depositional activ- ity. Near the outer edge of the marsh it crosses the belt of sedges. Farther back it is bordered by vari- ous societies. Where it cuts into the grass- covered areas erosion by undermining is going on, and a section of peat sometimes 0.6 m. in height is exposed. For considerable distances shrubs are also being undermined, and at one point the stream in its meandering has invaded the area of former swamp forest and has caused the overthrow of many trees. The material eroded from the banks is deposited where the current slackens, and in such places the normal succession of plant stages is in progress; aquatics first, followed by a sedge mat when the McCargoe’s Cove vvvvV\I b v ' vv ty Upland CARN DD, Wy Fic. 50.—Sketch map of the delta at the head of McCargoe’s Cove. 1913] COOPER—ISLE ROYALE 219 deposit reaches the surface. Frequently the first invaders are stools of sedge or rootstocks of Nymphaea and Calla which have been washed out from some eroding portion of the shore. It may thus be seen how the plant life supplements the physio- graphic processes. Upon one bank the current may be steadily destroying the vegetation (grasses, shrubs, and even trees); while on the other, where deposition is in progress, the same types are being developed through the normal course of the swamp succession. Note should be made of the peculiarly rich aquatic flora which inhabits the shallows of this and similar sluggish streams. The list of species obtained in the several localities of this type includes the following of special interest: Nymphaea advena Ait., Vallisneria spiralis L., Utricularia vulgaris L. var. americana Gray, U. inter- media Hayne, U. minor L., Myriophyllum verticillatum L. var. pectinatum Wallr., M. spicatum L., M. alterniflorum DC, Potamo- geton natans L., P. alpinus Balbis, P. amplifolius Tuckerm., P. heterophylius Schreb., P. heterophyllus {. terrestris Schlecht., P. praelongus Wulf., P. perfoliatus L., P. zosterifolius Schumacher, P. obtusifolius Mertens and Koch, P. filiformis Pers., Callitriche palustris L., Castalia tetragona (Georgi) Lawson, Bidens Beckii Torr., Scirpus subterminalis Torr., Sparganium diversifolium Graebner, S. minimum Fries, Sagittaria latifolia Willd. f. hastata (Pursh) Robinson, S. cuneata Sheldon, Lemna trisulca L., Ceratophyllum demersum L., Hippuris vulgaris L., Glyceria borealis (Nash) Batchel- der, Calla palustris L., Isoetes macrospora Dur. Though not a plant, Spongilla should “ mentioned as an important element in the aquatic life. At the head of Duncan Bay there are two delta swamps, both smaller than the one just described. One of these was studied with care, and the locality is included here because the swamp forest is well developed. Fraxinus nigra is the pioneer, and is present, but not abundant, in the mature forest. Thuja comes next and is the most important species. Larix, Picea canadensis, Abies, and Betula alba var. papyrifera, in order of abundance as named, com- plete the list. In passing toward the shoreward edge of the swamp forest Larix is the first to disappear. Thuja holds out much longer, and the ground is covered in places with tangles of layered branches 220 BOTANICAL GAZETTE [MARCH from it. The young trees are largely balsams. The herbaceous growth is practically the same that is found in the bog forest. It will be noted that all the trees of the climax forest are present here, and that the stages are telescoped as in the bog succession. A locality where the climax condition had been almost attained was found in a narrow stream valley at the head of Brady Cove (Sec. 18, T. 66.N., R. 35 W.). The forest here, which fills the valley, is of the climax type except for an occasional ancient Thuja and a slight admixture of Fraxinus nigra. Fallen trunks of Thwa are fairly numerous. The shrubs and herbs are a mixture of swamp forest and climax forest species. That there is a general resemblance between the bog succession and the delta swamp succession is very evident. There are also some striking differences which are constant in the localities studied. Most important of these are the following: sedge mat not floating; interpolation of grass stage as the most important peat-forming agency; absence of sphagnum, true bog shrubs, and Picea mariana; dominance of Thuja in the swamp forest. It is conceivable that under certain circumstances one succession might pass over into the other. This seems to have happened at the head of Siskowit Bay just north of Senter Point. A large swampy area has been cut off from the bay by a high curving beach ridge 1 km. long. That there was originally a delta swamp here is shown by the presence of a remnant of the former stream, a winding strip of water ending abruptly against the outer ridge. For some reason, possibly on account of post-Nipissing tilting, the current of the stream became insufficient to keep its outlet open in opposition to the vigorous wave action upon the shore of the bay. The resulting stagnancy has brought about a partial change to bog conditions. The former stream is partly filled with an open growth of Menyanthes, Equisetum fluviatile, Utricularia intermedia, and Potamogeton heterophyllus. Along the water’s edge there is a band of nearly pure Carex filiformis, recently established. The body of the swamp is occupied by a sedge-grass society, in which Scirpus caespitosus is dominant. Accompanying species are Carex exilis Dewey, Muhlenbergia racemosa (Michx.) BSP, Sarracenia purpurea L., Vaccinium Oxycoccos L., Aster umbellatus Mill. var. pubens STEAM Se PRP ESOR SE ie ot poe, Ses fp) SS eee eee 1913] COOPER—ISLE ROYALE 221 Gray, Solidago uliginosa Nutt. Shrubs are scattered over the whole area, the principal species being Potentilla fruticosa L. and Myrica Gale L. The bog forest is of considerable extent and the trees are Thuja, Larix,and Picea mariana. Near the forest edge there is con- siderable sphagnum in hummocks much overgrown with grasses and other plants. The composite character of the vegetation in this locality is plain. It is certain that the change from swamp to bog conditions has been very gradual, and it is possible also that there has always existed here a slight element of bog vegetation. THE SECONDARY SUCCESSION The burn succession I. Causes and extent of fires upon Isle Royale During the period of mining activity upon Isle Royale fires were of frequent occurrence and many square kilometers were swept by them. Since the abandonment of the mines they have been much less frequent, so that most of the burned areas found today have already gone through a considerable period of forestward development. There is evidence that fires occurred long before the appearance of white men. A layer of burned wood deeply buried was found in the humus upon Smithwick Island, where otherwise absolutely no sign of burning was to be seen. Such fires must have been started either by Indians or by lightning. It is nearly certain that fire has played a part in the vegetational history of almost all if not the entire forested area of the island. II. Effect of fire upon the climax forest The effect of the destruction wrought by a forest fire is essen- tially to bring about a return to a more or less xerophytic condition, which is followed by a readvance leading again to the climax forest. . The secondary development may be along the line of the original Primary succession, but factors are usually present which bring about pronounced modifications in the process. Obviously the burn succession is exceedingly variable, and cannot be described in terms that will even approximately fit every case. The variable factor that is most important in creating differences in the succes- sion is the severity of the fire. In respect to this two cases may be roughly distinguished. 222 BOTANICAL GAZETTE [MARCH 1. Humus little harmed.—This is the commonest type of burn upon Isle Royale and results in the development of a characteristic “burn forest’’ preceding the reestablishment of the climax. The composition of such a forest is mainly the outcome of the differing success with which the various species withstand the effects of the Fic. 51.—Recently burned area on Fic. 52.—Young birch stump sprouts Smithwick Island: fireweeds dominant; in a two-year-old burn near Siskowit a relict birch at the left; unburned forest Lake in the background. fire. The coniferous element of the climax forest, consisting of Abies balsamea and Picea canadensis, is entirely eliminated by a fire of any severity. Betula alba var. papyrifera, on account of its dry papery bark, is very inflammable, and the aerial portions are quickly destroyed. The underground parts, however, are not killed as are those of the conifers. They persist with great tenacity through most unfavorable conditions, provided the humus in which ONE WEN POMEOE ST oer 3 SR a ae Oe ee Re TE gee TE — 1913] COOPER—ISLE ROYALE 223 they are buried is unharmed, and are the most important con- tributors to the forest which immediately begins its development. Pyrus americana is similar to the birch in this respect, but is much less abundant. The shrubs of the climax forest seldom survive, though occasionally in a moist hollow a clump of Taxus will persist. The plants of the forest undergrowth, being close to the damp ground, frequently live through the fire. Some of them quickly succumb to the hard conditions which ensue, but certain species seem to thrive better than ever after the destruction of the forest cover. Prominent among the latter class are Cornus canadensis, Linnaea borealis var. americana, and Maianthemum canadense. These, which usually grow rather sparsely in the shade of the climax trees, come to cover large areas, flowering and fruiting luxuriantly. The first is one of the most characteristic species in the undergrowth of the burn forest. Upon areas where the forest has been destroyed but the humus little harmed the progress of the burn succession is commonly as follows. During the first growing season after the fire those relicts which have survived renew their growth, and many new arrivals appear. Certain of the latter are much the most prominent features for a number of years. These are the familiar fireweeds, Epilobium angustifolium L. and Anaphalis margaritacea (L.) B & H. (fig. 51). Biiouck the fireweeds give tone to the landscape for the first few years, the trees of the future forest begin their development equally early. The birches of the original stand, whose subter- ranean parts are still alive, sprout luxuriantly from the stump (figs. 52, 53). Often a ring of a dozen or more shoots appears where a single birch of the previous generation stood. Many of these die, but some develop into trees. Seedling birches and aspens (Populus tremuloides) add to the number, but upon Isle Royale the birch sprouts greatly predominate. The result is the development of a forest composed mainly of even-aged birches in clumps of 2-6 or more (fig. 54). A rich shrubby vegetation accompanies the trees. Rubus idaeus var. aculeatissimus is usually the first. Diervilla Lonicera Mill, Corylus rostrata Ait., and Rubus parviflorus Nutt. follow. When the birches have attained a size sufficient to produce 224 BOTANICAL GAZETTE [MARCH moderate shade, the last named shrub (white-flowered raspberry) often forms a dense tall thicket growth beneath them. There is also a characteristic group of herbs that follow close upon the decline of the fireweeds. These are Castilleja pallida (L.) Spreng. var. septentrionalis (Lindl.) Gray, Lilium philadelphicum L., Pleris aquilina L., and others in the early stages; and Aster macrophyllus L., very abundant in the mature burn forest. A forest mainly of birches in clumps, with undergrowth as described above, is prac- tically certain indication that fire has recently visited the area. Fic. 53.—A group of birch stump sprouts in an area that was burned about 35 years ago: the original trunk is shown; near Park Place Hotel Frequently neighboring burns of different ages are indicated by patches of birch forest of differing height. None of the areas of burn forest of historic age upon Isle Royale are old enough to show the late stages in the transition to the climax. The process is indicated, however, by the frequent occurrence of young spruce and balsam under the light shade ol the birches. Occasional conifers germinate immediately after the fire, but the thorough occupation of the ground by the fireweeds and the rapid growth of the birch sprouts, as well as the dryness 01 the ground, prevent them from starting in abundance. The devel- 1913] COOPER—ISLE ROYALE 225 opment of the burn forest is exceedingly rapid, thanks to the prolific sprouting of the birch, but the transition from burn forest to climax seems to be a slower process. Occasional areas of climax forest in which the birch element is mainly composed of groups of immense stump sprouts probably represent the penultimate stage in a burn succession following some prehistoric fire. The effect of fire upon the composition of the flora is shown in table VI. The statistics were obtained from a study of areas of equal size in the unburned and burned portions of Smithwick Fic. 54.—A young burned forest composed mainly of birches in clumps: the lower aie th i is J oth communis var. depressa, Pleris aquilina, and other species; near Park Place Hot Island. The fire occurred about 1 5 years ago. The points to be noted are the destruction of the conifers and a part of the herbace- ous flora, the increase of Betula and another portion of the her- baceous vegetation, and the appearance of Populus, Rubus, and the fireweeds. 2. Humus destroyed; bare rock exposed.—In such cases the reestablishment of the climax follows closely along the line of the rock shore succession, through lichen and crevice plant, and heath mat stages. Such differences as occur are due to the more thorough disintegration of the rock with greater abundance of soil materials 226 BOTANICAL GAZETTE [MARCH resulting therefrom; the presence of more or less humus at the beginning (it rarely happens that fire destroys every vestige of organic matter, and even a very small quantity in a rock crevice is of great assistance in hastening the establishment of vegetation) ; frequent protection from the drying and mechanical effects of wind; TABLE VI Species Climax forest Burn PICS ASAIO oe i eine ois ss 65 I Betula alba var. papyritera, <2... 2. i ss 6 117 (sprouts) Picea oo ee ee eee Se I a Da re eS oa res 13 ae Populus reeculoeiee eet Pewee Cok a 16 PEERS CONACERSIS ©) 55 5 oa eh oe vcs 14 ne WiburiiiD DAUCHOMUI. es ss I I Rubus idaeus var. aculeatissimus......... 5 74 Wee DUCICAMNS Cf oh ee eke bea es 21 MME MO eg a ee ev ons es 21 Werte BERICOG os si ne seins 13 Linnaea borealis var. americana.......... 6 30 in MAG pian vod oes Ss 2 Epilobium angustifolium................ 806 AUepnals MAreAritaces ..........0.55 421 Maianthemum i ae et ree a ag 312 Calamagrostis canadensis............... 83 * Frequent in most parts of climax forest. presence of a large body of invaders ready to advance from all directions. All these modifying influences tend to hasten the progress of the succession. Areas where fire has exposed the bare rock are found principally upon the tops of ridges, since the soil in such places is usually both shallow and dry, and whatever remains after the fire is washed away to lower levels. III. Effect of fire upon the xerophytic and bog forests When the jack pine—black spruce forest is burned, much of the humus is apt to be destroyed also, as the soil is commonly thin and dry. A few observations indicate that this type often succeeds itself. The pine grows faster and so for a number of years is the dominant tree. In one burned locality was found an open growth of pines 4-7 m. high, even-aged, averaging 28 years. Beneath 1913] COOPER—ISLE ROYALE 227 them were scattered black spruces, few more than 1 m. high, also even-aged, and averaging more than a year older than the pines. In extensive fires the patches of bog forest occupying the depres- sions often escape entirely because of abundant moisture. When they are burned over the coniferous element is destroyed, and the birches if present sprout from the stump. The underground por- tions of the two species of Alnus survive and renew growth, and the result is frequently a dense alder-birch thicket, which probably passes directly into the climax type. When the scattered trees growing upon an open bog are killed by fire the sphagnum, being usually saturated with water, seldom suffers severely. New bog trees begin growth and the succession goes on as before. SUMMARY.—THE SUCCESSIONS Primary successions The xerarch successions Every part of Isle Royale has at some point of its subaerial history been shore. The present coast of the island is made up of rock shores and beaches, the former being much the more extensive. Each type possesses its characteristic series of successional stages, the ROCK SHORE SUCCESSION and the BEACH SUCCESSION, both resulting finally in the establishment of the climax forest. With regard to area vegetated through its instrumentality, the rock shore succession is by far the most important of all the suc- cessions of Isle Royale. The full series of the rock shore succession includes in its early stages three subsuccessions which later unite into a single series. The rock surface subsuccession advances through crustose lichen and foliose lichen stages to a condition in which the large cladonias are the most important element. The process of invasion along this line alone is very slow. The pioneers of the crevice subsuccession are certain herbs, notably Potentilla tridentata, whose principal réle is the formation of humus. Trailing shrubs succeed them, the most important being J uniperus horizontalis, J. communis vat. depressa, and Arctostaphylos Uva-ursi. These spread over the rocks from the 228 BOTANICAL GAZETTE [MARCH crevices in all directions, and weaving among the cladonias and plants of the rock pools bring about the formation of a firm mat. The crevice vegetation is of extreme importance because of its rapidity of development and its preeminent part in the formation of the heath mat. Forest establishment is accomplished much sooner where crevices are abundant in the rock than where they are scarce. The rock pool subsuccession goes through its development in depressions where water stands at least a part of the time. These become gradually filled after the manner of the bog succession, and the vegetation later becomes an element in the formation of the heath mat. The heath mat results from the coalescence of the vegetation developed through the instrumentality of the three subsuccessions named above. The climax forest often follows immediately after the formation of the heath mat, the trees obtaining their first foothold in the crevices. A relatively xerophytic forest stage characterized by Pinus Banksiana and Picea mariana sometimes intervenes, in which Pinus is the pioneer and Picea remains for some time after the climax trees have attained dominance. Telescoping of stages is pronounced throughout the series, so that pioneer and climax forms, with those of all intermediate stages, are frequently found occupying a single limited area. The effect of special conditions upon the rock shore succession is expressed in the two following laws: t. The lower limit of possible forest extension is determined approximately by the upper limit of effective wave and ice work, the lake level remaining constant. 2. The extent to which the forestable territory has been occupied at the present day depends upon the rapidity of invasion, which is governed by the character of the rock, the angle of slope, and the degree of exposure to winds. The operation of these laws results in the production of three phases of rock shore vegetation, characterized respectively by (A) climax forest to the water’s edge, (B) a zone of incomplete invasion, (C) abrupt transition from bare rock shore to climax forest. 1913] COOPER—ISLE ROYALE 220 During the early subaerial history of Isle Royale the rock shore succession may have differed from that of the present day. A study of Gull Islands indicates that birds may have been important agents in determining the composition of the primitive rock shore flora of the island. The beaches on account of their sheltered location usually bear the climax forest down to its limit of possible extension. Low shrubs of various kinds are the most important pioneers in the beach succession, and larger ones, especially Alnus crispa, intervene before the establishment of the climax type. The hydrarch successions The bog succession Physiographic development.—The depressions which now contain lakes or bogs owe their origin to glacial modification of the preglacial topography; sometimes to the cutting off of bays or channels by wave-built bars. The physiographic history of the habitat in which the bog succession runs its course comprises two stages: the channel-bay stage and the lake stage. The lakes and harbors are tending toward extinction through the agencies of down-cutting of outlets, sedi- mentation, and vegetation, of which the last is the only one of importance at the present time. The lake stage ends when vegeta- tion, aided by the other agencies, has entirely eliminated the open water. Vegetational development.—During the channel-bay stage aqua- tics first appear and gradually increase with increasing shelter; the beginnings of the sedge mat are occasionally present. During the physiographic lake stage all the vegetational stages of the succession appear in order: aquatics (usually already present), sedge mat, sphagnum-shrub, bog forest. All may have their beginnings at practically the same time. The sedge mat is usually the most prominent feature at this period. The sedges gain their first foothold in shallow water close to shore and build a floating mat out over the water. They are by far the most impor- tant agents in peat formation. uring the covered bog stage the plant societies are successively eliminated by the centripetal encroachment of the various zones. 230 BOTANICAL GAZETTE [MARCH Two lines of succession are distinguished after the sedge mat stage. One is characterized by Chamaedaphne, Andromeda, and Alnus incana in the shrub stage, practical absence of sphagnum, and by Larix and sometimes Thuja in the bog forest; the other by Chamaedaphne and Andromeda followed by Ledum in the shrub stage, abundance of sphagnum accompanying the shrubs, and by Larix and Picea mariana in.the bog forest. Sphagnum is the critical plant in the differentiation of the two series, since Ledum and Picea mariana appear later, and only in cases where sphagnum is abundant. The differences may be related to differences in drain- age, since those bogs containing little sphagnum are usually well drained, while in those with abundance of sphagnum, as far as observation has gone, drainage was very poor or lacking entirely. A contributing factor is found in differences in the composition of the sedge mat preceding the shrubs and sphagnum. In the sphag- num bogs Carex limosa is the principal mat-forming species. Being low and soft, it offers no resistance to the spread of the moss. In the bogs with little sphagnum Carex filiformis is the important mat-former. On account of its height and stiffness and dense growth it produces unfavorable conditions for the spread of sphag- num. The reason for the differing distribution of the two carices is unknown; it may be merely accidental. The sphagnum is a superficial layer supported upon the sedge mat, and contributes little toward peat formation. It begins growth some distance within the bog margin and spreads both ways, slowly toward the margin, faster centerward. The area between the sphagnum and the upland commonly forms a marginal trench. In some places the moss by recent invasion has obliterated the mar- ginal trench, and occasionally it transgresses the bog margin, spreading up the forest floor for several meters. The sphagnum spreads marginally, surrounding and smother- ing such plants as cannot keep pace with its growth. Certain species by upward elongation are able to survive for some time, especially Andromeda and Chamaedaphne, the latter persisting longest. Ledum almost invariably follows the sphagnum, and its root system is usually strictly confined to the masses of it. It forms 4 1913] COOPER—ISLE ROYALE 231 very dense growth, and through its shading power and ‘he great amount of waste that falls from it finally eliminates the lower shrubs and ‘stops the upward growth of the moss. The bog trees, Larix, Thuja, Picea mariana, usually follow the sphagnum when it is present. When it is lacking they start upon the sedge mat with the shrubs. The climax trees enter very soon after or often actually with the bog trees, so that pure bog forest is practically absent. The bog trees die out because they are intolerant of shading, and the climax forest results. Telescoping of stages is prominent throughout the late history of the succession. The reason for the early establishment of the climax forest is found in the likeness between the bog soils and those of the forested uplands, the latter being almost as peaty as those of the bogs. It follows that whatever trees can grow upon one soil may also exist upon the other. The delta swamp succession Delta deposits are found in most of the sheltered bays where Streams enter from the upland. The succession of vegetation upon these deposits passes through the following stages: (1) aquatics; (2) sedges; (3) grasses (Calama- grostis canadensis most important), which form broad meadow-like growths and produce a limited amount of peat; (4) shrubs, among which Myrica Gale and Alnus incana are most important; (5) swamp forest, made up of Thuja occidentalis, Larix laricina, and Fraxinus nigra, the first being dominant; (6) climax forest of Abies balsamea, Betula alba var. papyrifera, and Picea canadensis. There is a general likeness to the bog succession; among other points, in the early establishment of the climax forest after the coming in of the swamp trees. The important points of difference from the bog succession are: the firmly grounded sedge mat; interpolation of the grass stage; absence of sphagnum, bog shrubs, and Picea mariana; dominance of Thuja in the swamp forest. Intermediate conditions between the two successions occur, and actual transition from delta swamp to bog succession occasionally takes place. 232 BOTANICAL GAZETTE [MARCH Secondary succession The burn succession The effect of fire upon the climax forest is to bring about a return to a more or less xerophytic condition, which is followed by a readvance leading to the climax. Two general cases may be distinguished. 1. Humus little harmed.—The coniferous element is destroyed, but the birches survive in their underground portions and sprout abundantly from the stump, usually producing a nearly pure 3 B[Lrke Rock Shore CLIMAX _ FOREST = E Succession (Abies, Betula, Picea canadensis) S|z* Rs bia = 2 be] _ > rn Forest bd lefsprou ae OF s) Xerophytic Forest Bog Forest ve Maxie Swamp Forest | é ireweeds, sie dgpiandanar (are a ices ariana) ee a = —, — ce oe Shrubs _ f a nigra) naphal hus crispa, ae eas — st ; ifera, sicratal. Seem ee ea a alix spp, Shi de yrica, Bog ay cent sy Alnus incana) (Chamaedaphne, Andromeda) t Andromeda, a Grasses Cladonias Crevice Shrubs Shrubs Shrubs Alnus incana) me (Calamagrostss f (Juniperus, (Vaccinium (Rubus idaeus, “s._ canadensis) Foliose Lichens, Arctostaphylos) uliginosum) Diervilla, os, Hedwigia Physocarpus) aia at ed | Mat Crustose Lichens, Crevice Herbs Turf Mat af Herbs Aquatics Aquatics Grimma otentilla ; Gcirpus A Rock Surface Crevice Rock Pool Subsuccession Subsuccession Subsuccession | I Se Rock SHQRE Succession Beacu Succession Boc Succession DeLtaSwamPSuccESsion “, eo XERARCH SUCCESSIONS HYDRARCH SUCCESSIONS PRIMARY SUCCESSIONS Fic. 55.—Diagram to illustrate the courses of the various successions upon Isle Royale. forest of birches growing in clumps. Seedling birches and aspens are usually present also. Conifers gradually return, finally bringing about the reestablishment of the climax. 2. Humus destroyed; bare rock exposed.—The reestablishment of the climax follows closely along the line of the rock shore succes- sion, but progress is usually more rapid because of the presence of soil materials and numerous invaders, and frequently protection from wind. The courses of the various successions and their relations to each other are shown graphically in the diagram (fig. 55). Pato ALTO, CALIFORNIA 1913] COOPER—ISLE ROYALE 233 LITERATURE CITED 1. Apams, C. C., Postglacial origin and pes tisosoerl of the life of the north- eastern United States. Jour. Geog. I:no. 7. 190 2. , The postglacial dispersal of ‘tis Hee Aunsricas biota. Biol. Bull. 9253-71. 1905. , An ecological survey in northern Michigan. A report from the University Museum, University of Michigan, published by the State Board of Geol. Surv. as part of report for 1905. Lansing, Mich. 1906. Pp. 48-55 and 86-92, written by Dr. A. G. RUTHVEN, deal with the plant ecology of Isle Royale. 1906. , An ecological survey of Isle Royale, Lake Superior. A report from the University of Michigan Museum, published by the State Biol. Surv. as a part of Rep. Geol. Surv. 1908. Lansing, Mich. 1909. Con- tains the following sections dealing directly or indirectly with the plant ecology: Isle Royale as a biotic environment, pp. 1-53, by C. C. ADAMS; The ecological relations of the invertebrate fauna of Isle Royale, Mich., Pp. 57-78, by H. A. GLEAson; Notes on the vegetation of Isle Royale, Michigan, and annotated list of plants, oe 21 le by W. P. Hott. 5. ATkINson, G. F., College Botany. New 908. 6. Ayres, H. B Nebo aren of the pine ome of Minnesota. U.S. ol. Surv. Niet Ann. Rep., Pt. V. 673-689 7. BELL, Ropert, The ae Peninsula. ‘abe ar Mag. 11:335-361. 1895. , Distribution of forest trees in Canada. Scot. Geog. Mag. 13: 281- 9. Clements, F. E., The rebse zane and structure of vegetation. Rep. Bot. Surv. Nebraska. VII. To. , Research methods in eco “eniae Lincoln, Neb. 1905. x. Cootey, Grace E., aoe features of Larix americana. Forestry Quart. 2:148-160. 1 12. Cooper, W. S., Reproduction by layering among conifers. Bot. Gaz. 52:369-379. Igrr. Aaa. , The ecological succession . ome as illustrated upon Isle Royale. Plant World 15:197-213. 13. Cowtes, H. C., The ee ccslliey of Chicago and vicinity. Bor. AZ. 31:73-108, 145-1 : , The influence of "ialeiviog rocks on the character of the vegeta- tion. Bull. Amer. Bur. Geog. 221-26. figs. 10. 1901. 15. ———, The causes of vegetative cycles. Bort. Gaz. 51:161-183. rgrt. 16. DacuNowsk1, A., The toxic property of bog water and bog soil. Bor. AZ. 46:130-143. 1908. 17. ———, The venctntion of Cranberry Island (Ohio) and its relations to the substratum, temperature, and evaporation. Bot. Gaz. 52:1-33, 126- I50. IQIr. 234 BOTANICAL GAZETTE [MARCH 18. Dana, S. T., Paper birch in the northeast. U.S. Dept. Agric. Forest Service, Circular 163. 1909 1g. Davis,C.A., Peat: Essays on its ae ak uses, and distribution in Michigan. Mich. Geol. Surv. Ann. Rep. 1906 (1 20. FERNow, B. E., An analysis of Canada’s s ee wealth. Forestry Quart. 6:337-353- I 908. . Funk, Bruce, The lichens of Minnesota. Contrib. U.S. Nat. Mus. 14: ras 69+xvi. I9Q10. 22. Forest SERVICE, U.S., The white spruce. Silvical Leaflet 15. 1908. 23. Foster, J. W., and WuItNey, J. D., Report on the geology and topography of a portion of the Lake Superior land district, in the state of Michigan. Exec. Doc., 1st Sess., 31st Cong. g:pt. 1. 1850 Rie on the geology of the take Supeciue land district. Pt. II, the ion region. Sen. Doc., Spec. Sess., 32d Cong. 3:1851. Contains a list of plants of the Upper Penasals by W. D. Wurtney, including some from Isle Royale. 25. Fox, W. F., The Adirondack black spruce. Ann. Rep. N.Y. Forest Comm. 1895. 26. Ganonc, W. F., Preliminary outline for a plan for a study of the precise factors dpveccining the features of New Bru age vegetation. Bull. Nat. Hist. Soc. New Brunswick 17:127-130. 18 , A preliminary synopsis of the grouping ee the vegetation (phyto- ography) of the province of New Brunswick. Bull. Nat. Hist. Soc. New Brunswick 21:47-60. 1902. , The nascent forest of the Miscou beach plain. Bort. Gaz. 42:81- 106. 1906. 29. GLEason, H. A., The ecological relations of the invertebrate fauna of Isle Royale. In Apaus 4. 30. Graves, H. S., This study of natural reproduction of forests. Forestry Quart. 6:115-137. 1908. 31. GREEN, S. B., Forestry in Minnesota. St. Paul. 190 32. HARSHBERGER, J. W., An ecological study of the ‘ick of mountainous North Carolina. Hor. GAZ. 32:241-258, 368-383. 1 33- Hott, W. P., Notes on the vegetation of Isle Royale, Mich., and annotated list of slants. In ADAMS 4. I909. 34. Howe, C. D., The reforestation of sand plains in Vermont. Bor. Gaz. 49: 126-148. IgI0. 35. KNECHTEL, A. Apo reproduction in the Adirondack Soctatic Forestry Quart. 1:50-55. 190. 36. Lang, A. C., Geolany a Isle Royale. Geol. Surv. Mich. 6:pt. 1. 1898. 37. Livrncston, B. E., The relation of soils to natural vegetation in Roscom- mon and Crawford counties, Michigan. Bor. Gaz. 39:22-41. 1905. 38. MacMurray, C., On the occurrence of sphagnum atolls in central Minne- sota. Minn. Bot. Stud. Bull. 9. 1893. 24. 27: 28. 1913] COOPER—ISLE ROYALE - 235 39. Macoun, Joun, Catalogue of Canadian plants. Geol. and Nat. Hist. Survey of Canada. 1883-1890. , The forests of Canada and their distribution, with notes on the more interesting species. Trans. Roy. Soc. Canada 4:3-20. 1 41. Moore, B., and Rocers, R. L., Notes on balsam fir. Posty Quart. 5:41-50. 190 : 42. OLSSON-SEFFER, P., Examination of organi ins in postglacial deposits Amer. Nat. 37:785-797. 43- Ontario dept. of crown ie Report of the survey and exploration of 40. gor). 44. Pincuot, G., and Graves, H. S., The white pine. New York. 1806. 45- Quebec dept. of lands and forests, The regions of Quebec, Lake St. John, Chicoutimi, and of the north shore of the St. Lawrence. 1908. , Report of the minister of lands and forests of the province of Quebec. 1909 (1910). 47. Rostnson, B. L., and Fernap, M. L., Gray’s Manual of botany. Ed. VI. New York. 1908. 48. Roru, F., On the forestry conditions of northern Wisconsin. Wis. Geol. and Nat. Hist. Surv. Bull. (Economic ser.) no. 1. 1 49. RuTHVEN, A. G., Notes on the plants of the Porcupine Mountains and Isle Royale, Michigan. In ADAMs 3. 1906. 50. SARGENT, C. S., Manual of the trees of North America. Boston and New York. 1905. 51. ScHwarz, G. F., The sprout forests of the Housatonic Valley of Connecti- cut. Forestry Cua 5 2121-153. 1907. 52. SHAW, C. H., The development . vegetation in the morainal depressions of the vicinity of Woods Hole. Bort. GAZ. 33:437-450. 1902. 53- Stupart, R. F., The climate of Suk Scot. Geog. Mag. 14:73. 1808. 54. TRANsEAU, E. N., On the geographic distribution and ecological relations of the bog plant societies of North America. Bot. Gaz. 36:401-420. 1903. 46. , Forest centers of eastern America. Amer. Nat. 39:875-880. , The bogs and bog flora : = Huron River Valley. Bot. Gaz. 40 :351-375, 418-448. 1905; 41:17-42. 1906. 57. , Successional relations Fe vegetation about Yarmouth, N.S. Plant World 12:1-11. 1909. 58. WHEELER, W. A., Notes on some plants of Isle Royale. Minn. Bot. Stud. 2:619-620. Igor. 59. WuITForp, H. N., The genetic development of the forests of northern Michigan. Bor. Gaz. 31: 289-325. 1901. ZEDERBAUR, C., The light requirements of forest trees and the methods of measuring light. Forestry Quart. 6: 253-262. 1908. Fy STUDIES ON THE PHLOEM OF THE DICOTYLEDONS ii. THE EVOLUTION OF THE SIEVE-TUBE CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 169 ANSEL F. HEMENWAY (WITH PLATE XI AND THREE FIGURES) In 1909-10 the writer studied the phloem of some 30 species of lower dicotyledonous trees and found that the sieve-tubes in these species had the same general structure as those of the gym- nosperms or vascular cryptogams.t Some 60 species of higher woody dicotyledons were investigated the next year, and this last year about go species of herbaceous dicotyledons and 12 monocotyledons have been studied. As the literature on the subject of phloem has been rather well reviewed and catalogued recently, an exhaustive review of it will not be given here. In 1908 Hirt? gave a good review of the literature from the histological standpoint. MANHAM® similarly discusses the literature from the physiological side. CHAUVEAUD‘ in an extensive paper gives a brief review of the literature of phloem. The material for this investigation was collected in late summer or early fall, the object being to get the sieve-tubes in mature condition, so that they would best show callus formation. For the sake of comparison, several species were studied in seedling condition and in the adult growing condition. Before proceeding to the discussion of the evolution of the sieve-tube, a few general observations on phloem anatomy may well be mentioned. The distribution of the hard bast in the woody MENWAY, ANSEL F., Studies on the phloem of the dicotyledons. I. Phloem of va Juglandaceae. Bor. Cx: 51:131-135. pl. 13. 191t. ‘ ? Hitt, A. W., The histology of the sieve-tube of angiosperms. Ann. Botany 22:245-290. pls. 17, 18. figs. 13. 1908. 3 Manuaw, S., The conduction of carbohydrates. Science Prog. Oct. 1910 and Jan. 1grt. « 4 CHavveavp, G. L., L’appareil conducteur des plantes vasculaires et les phases principales de son Gvohution. Ann. Sci. Nat. Bot. IX. 13:113-438. figs. 218. 1911. Botanical Gazette, vol. 55] [236 1913] HEMENWAY—SIEVE-TUBE 237 dicotyledons is very characteristic for each species and usually for each genus. In many cases it is arranged in bands concentric with the cambium, as in Acer, Populus, and Crataegus; in some cases in groups opposite the large or aggregate rays, as in Alnus, Carpinus, and Drimys; in other cases in irregular patches, as in Ostrya and Celtis; and finally, in various combinations of these arrangements, as in Quercus. Plate figs. 1-3 show some of these peculiarities of phloem structure. Fig. 1 is a transverse section of Acer macrophyllum; the lighter horizontal bands are the hard bast cells; between these are the sieve-tubes and parenchyma cells; while the dark vertical lines are the phloem rays; in the lower portion of the figure the cambium and some xylem are seen. Fig. 2 is a similar view of Alnus incana; here we note that the hard bast occurs chiefly opposite the aggregate ray. Fig. 3 is a similar view of Quercus Garryana; a large group of hard bast is seen above the large ray in the lower left portion of the figure, while several smaller groups appear here and there in other parts of the phloem. Fig. 4 is a transverse section of the stem of Ranunculus fascicu- laris; the central, lighter portion of the three bundles shown here is phloem. Fig. 5 is a similar view of Chenopodium album, and fig. 6, of Amaranthus paniculatus. The darker areas just above the groups of large vessels are phloem. This peculiar, scattered arrangement of bundles in a woody cylinder would suggest a pos- sible point of origin for the monocotyledons. Companion cells are rare if not wanting in many of the lower dicotyledons. It is probable that parenchyma cells play the part of companion cells here. The end walls of the ray cells in the phloem of some woody dicotyledons show sieve-platelike pitting, but they did not show any callus formation. This formation is easily observed in tan- gential sections of Phellodendron, Rhus, Ilex, Acer, Gymnocladus, Acanthopanax, and many other species. There are often thick- walled, unlignified, phloem-parenchyma cells in both woody and herbaceous dicotyledons that show lateral sieve-platelike pittings, but no terminal sieve-plates or callus were seen. In the herbaceous dicotyledons studied, often the most striking 238 , BOTANICAL GAZETTE [MARCH feature was the relatively small amount of phloem present. In Paeonia and Thalictrum, for example, there may be only 6-12 sieve-tubes in a bundle having perhaps 30~50 times that number of xylem elements; but often in woody plants only a few rows of sieve-tubes, as seen in radial section, are really functional. Fics. 1-3.—Fig. 1, one-third of a sieve-tube of Juglans nigra: a, end sieve-plate in cross-section; 6, lateral sieve-plate in face view; fig. 2, one-half of a sieve-tube of Vitis labrusca: a, end sieve-plate in cross-section: 5, lateral sieve-plate in face view; ¢, companion cell; fig. 3, full length view of a sieve-tube of Lactuca scariola: a, end sieve-plate in cross-section, with callus; b, slime contents; c, companion cell; d, lattice or ‘“‘sieve-field.” No lignification of the phloem was observed in Helianthus. Perhaps the material used was collected too early or grew under different conditions from that described by BoopLE.5 ’ Boonie, L. A., Lignification of phloem. Ann. Botany 16:180. 1906; also ibid. 20: 319-321. 1910. 1913] HEMENWAY—SIEVE-TUBE 2390 Species of over 140 genera, belonging to more than 60 families, have been studied. The sieve-tubes found in these different species, for the sake of convenience, may be grouped under three types, though perhaps most of them will come naturally between the first and second or second and third types. The first type is like that found in Pinus. Here the lateral sieve-plates are the same as the terminal ones, and the end walls are very oblique, extending from one-fourth to one-half the length of the sieve-tube. Text fig. 1 shows one-third of a sieve-tube of Juglans nigra as séen in tangential view. The lateral sieve-plates are seen in face view on the tangential wall, while the terminal sieve-plates are seen in transverse section. The lateral sieve-plates on the tangential walls of the sieve-tubes in Juglans are usually more irregular and thinner than those on the terminal or radial walls. The second type is like the first except that the lateral sieve- plates are less well developed, and the end walls are less oblique, and have 2-10 sieve-plates each. This type may be illustrated by Vitis (text fig. 2). The figure shows one-half of a sieve-tube in tangential section. The end wall here has 7 sieve-plates covered with callus. Poorly developed sieve-plates are shown in face view on the tangential wall. On the left is a companion cell related to the sieve-tube by fine pits. The third type has end walls that are nearly at right angles to the side walls, and has only one sieve-plate to each end wall. The sieve-tubes of Lactuca scariola illustrate this type (text fig. 3). This sieve-tube, though shown in full length view, was drawn to the same scale as the other text figures. The three lattices on the left relate it to another sieve-tube. The species studied may be grouped under these types as follows: FIRST TYPE® Alnus incana, A. rugosa, A. oregana, Betula alba, B. lenta, B. lutea, Banksia Menziesii, Carya alba, C. ovata, Castanea dentata, Castanopsis chrysophylla, Casuarina Fraseriana, C. equisetifolia, Corylus americana, 6 The nomenclature of Gray’s Manual (Ed. 7) is followed as far as applicable; the names of plants indigenous to Oregon are those used in Howett’s Flora of Northwest America. 240 BOTANICAL GAZETTE [MARCH C. rostrata, Carpinus caroliniana, Drimys colorata, Fagus grandifolia, Juglans cinerea, J. nigra, Myrica asplenifolia, M. cerifera, Nothofagus” Menziesii, trya virginiana, Populus balsamifera, P. grandidentata, P. tremuloides, P. trichocarpa, Quercus alba, Q. Garryana, Q. Kelloggii, Q. nigra, Salix fragilis, S. nigra. BETWEEN FIRST AND SECOND TYPES Berberis aquifolium, Celtis occidentalis, Aesculus glabra, A. Hippocasta- num, Acer Negundo, A. macrophyllum, A. rubrum m, A. sac ccharum, Crataegus coccinea, C. Douglasii, Calycanthus floridus, Fraxinus americana, F. oregana, Hamamelis virginiana, Holodiscus ariaefolia, Hydrangea vestita, Liriodendron Tulipifera, Magnolia acuminata,- M. Fraseri, ra pomifera, Morus rubra, Philadelphus Lewisii, P.. grandiflora, Platanus occidentalis, Prunus serotina, Pyrus baccata, P. coronaria, Rosa gallica, Ribes sanguineum, Sassa- fras variifolium, Ulmus campestris, U. americana SECOND TYPE Ailanthus glandulosa, Arbutus Menzesii, Catalpa bignonioides, Ceanothus eus, Cephalanthus occidentalis, Cercis canadensis, Cladrastis lutea, Cornus Nuttallii, C. pubescens, Clethra alnifolia, Diospyros virginiana, Euonymus atropurpureus, Gymnocladus dioica, Gleditsia tricanthos, Ilex opaca, Kalmia latifolia, Lyonia ligustrina, Phellodendron amurense, P. japoni- cum, Robinia Pseudo-Acacia, Rhus glabra, R. Toxicodendron, Ricinus com- munis, Rhamnus cathartica, R. en Sxcabaacank glauca, Syringa vulgaris, Tilia americana, T. europaea, Vaccinium corymbosum, Vitis labrusca. BETWEEN SECOND AND THIRD TYPES Abutilon Theophrasti, Acanthopanax sessiliflorum, Actaea alba, Agri- h Clematis ligusticifolia, Brassica alba, Datura stramonium, Daucus Carota, Dipsacus sylvestris, Euphorbia Preslii, E. corollata, Filipendula rubra, Gera- nium sanguineum, Geum triflorum, Hibiscus Moscheutos, Hypericum per- foratum, Humulus Lupulus, Impatiens noli-tangere, I. pallida, Knautia arvensis, Paeonia montana, Potentilia rivalis, Polanisia graveolens, Poly- gonum Douglasii, Raphanus sativus, Rumex occidentalis, Saponaria officinalis, Solanum nigrum, Thalictrum dasycarpum, Tropaeolum majus, Urtica gracilis, Verbena officinalis. THIRD TYPE Ambrosia artemisiifolia, Arctium minus, Aster novae-angliae, Bryophyl- lum calycinum, Cichorium Intybus, Cicuta maculata, Cucurbita maxima, Cyclamen latifolium, Eupatorium purpureum, Echinocystis lobata, Eryngium yuccifolium, Helianthus annuus, Heracleum lanatum, Hieracium venosum, Lactuca scariola, Liatris squarrosa, Linaria ae, Lobelia cardinals, | fe So eee eC ee ee ae BO =, Saha eee iy 1913] | HEMENWAY—SIEVE-TUBE 241 Lupinus polyphyllus, Melilotus alba, Monarda punctata, Oenothera biennis, Opuntia Rafinesquii, Phaseolus vulgaris, Phytolacca decandra, Physalis heterophylla, Primula sinensis, Sium cicutaefolium, Scrophularia marilandica, Silphium laciniatum, Sonchus oleraceus, S. arvensis, Stachys palustris, Tephro- sia virginiana, i rinian pratense, Verbascum Thapsus, Veronica scutellata, Xanthium spinosu The ioe monocotyledons were similarily studied, and all were found to have sieve-tubes of the third type. Alisma Plantago, Arisaema triphyllum, ieee scandia, Iris versicolor, Monstera deliciosa, Polygonatum commutatum, Potamogeton heterophyllus, Sagittaria latifolia, Scirpus validus, Smilax eeincnte Typha latifolia, Zea Mays. There are of course no sharp lines of division in grouping these species according to type; even in the same section there may be some variation. But in general there is no wide variation even with different genera of the same family, except where there are both woody and herbaceous genera; then the herbaceous ones showed the higher type, as for example in Rosaceae and Legumi- nosae. The sieve-tubes of the Leguminosae on the whole are of a higher type than those of the Rosaceae. The woody Rosaceae often have sieve-tubes about like the first type, with regular large lateral sieve-plates. While the woody Leguminosae may have occasionally well developed lateral sieve-plates, they are usually as small as in Sambucus or Tilia. The xylem of the Leguminosae has been likewise found to be a higher type, so perhaps these families do not belong so near each other as they are usually placed. It will be noted that the woody dicotyledons studied are placed in the first and second types, while the herbaceous ones are in the intermediate type between the second and third, or in the third e. Three or four sieve-plates were the most seen on the end wall of any strictly herbaceous plant, as for example Euphorbia and Thalictrum. Even in these genera end walls with only one sieve-plate were often observed. In the Compositae studied, only one sieve-plate to each end wall of the sieve-tube could be . found. When stained with Russow’s callus reagent, the pores of the “sieve-fields” or lattices showed up as orange dots, but they never were large nor fused into callus pads. Occasional lateral callus pads were observed in most of the 242 BOTANICAL GAZETTE [MARCH other herbaceous plants studied. In Cucurbita maxima, for example, as many as 9g lateral callus pads have been seen in a continuous row in a single sieve-tube. __ The evolution of the sieve-tube parallels that of the tracheid or vessel. For example, in Ephedra the vessels have oblique end walls with several round or oval pits. This is supposed to be the primi- tive type of vessel. In Liriodendron the end wall of the vessel is still rather oblique, but the pits are of the scalariform type and close together. In the highest type, the pitted vessel, the little margin that is left of the end wall is usually at right angles to the side walls, as in Fraxinus. Conclusion In studying the phloem of the dicotyledons, it has been found that there is a gradual transition from the gymnospermous type of sieve-tube to the so-called dicotyledonous type as seen in the Compositae. At the first stage in advance the lateral plates are smaller and have smaller meshes than the terminal plates; then as the terminal wall becomes more and more at right angles to the lateral walls, the number of terminal plates decreases until there is only one terminal piste with relatively large meshes, and the lateral plates become “‘sieve-fields” or lattices. Paleobotany, ontogeny, and studies of xylem have induced many botanists to believe that herbaceous plants are more advanced in their evolutionary development than woody plants. This study of the sieve-tube adds another argument in favor of this view. The first two years of this work were done in the Phanerogamic Laboratory of Harvard University under the direction of Professor E. C. Jerrrey, and the last year of work has been under the direc- tion of Professors J. M. Courter and W. J. G. Lanp at the University of Chicago. The writer wishes to express his thanks to these instructors for their helpful advice. TRANSYLVANIA UNIVERSITY LExIncTon, Ky. PLATE XI TAZETTE, LV BOTANICAL «8 preesset S ~ AY on SIEVE-TUBE MENW 7 HE 4 BP rat as aa FO fon ie a SEES Sh « 1913] HEMENWAY—SIEVE-TUBE 243 EXPLANATION OF PLATE XI 1G. 1.—Transverse section of phloem of Acer macrophyllum, showing horizontal bands of hard bast and general view of sieve-tubes and parenchyma cells Fic. 2.—A similar view of Alnus incana, showing that the hard bast occurs chiefly opposite the aggregate rays. Fic. 3.—A similar view of Quercus Garryana, showing distribution of hard and soft bast. Fic. 4.—Transverse section of stem of Ranunculus fascicularis, showing scattered bundles and relatively small amount of phloem. Fics. 5 and 6.—Chenopodium album (fig. 5) and Amaranthus paniculatus (fig. 6), showing peculiar scattered bundles that might suggest relationship to the monocotyledons. ty pat BLOCKS FOR GROWING SEEDLIN GS_ IN LIQUID CULTURE SOLUTIONS? ConrAap HOFFMANN (WITH THREE FIGURES) In growing seedlings of any kind in nutrient solutions a suitable means of supporting the individual | plants is essential. The method commonly employed consists in the use of ordinary corks perforated so as to hold a varying number of seedlings. Invari- ably the corks are of such a size as to fit snugly in the neck of the vessel containing the nutrient culture solution. This apparatus, while satisfactory to a certain extent, offers several objections. The corks usually discolor the nutrient solution, the extent of discoloration depending upon the grade of cork employed, as well as upon the composition of the nutrient solution. This discolora- tion is due to soluble compounds, presumably organic in nature, which can be inferred to have some influence—beneficial or detri- mental—upon the growing seedlings. The corks soon warp and crack and become unfit for further use. Further than this, they furnish a substratum for molds, which frequently give trouble by infecting the seedlings to be grown. ese were some of the objections and difficulties encountered in the course of certain experimental work with growing seedlings. It was necessary in this work to grow a large number of seedlings in different culture solutions, which necessitated the employment of a large number of supports. The support which was finally adopted after considerable experimentation proved so satisfactory as to warrant its description and publication at this time. In place of the ordinary cork a paraffin block molded in the desired shape and size and perforated to suit the needs of the experi- ment has been used. It has been found advisable to employ a paraffin of comparatively high melting point, so as to prevent any melting or softening of the blocks under the direct rays of the sun to which they will be exposed in the course of their use. * Published with permission of Director of Wisconsin Experiment Station. Botanical Gazette, vol. 55] [244 1913] HOFFMANN—PARAFFIN BLOCKS FOR GROWING SEEDLINGS 245 To obtain blocks of the desired thickness and size, the following procedure has proved most effective. The paraffin is placed with sufficient distilled water in a suitable vessel and boiled vigorously. The paraffin can then be removed from the surface of the water Fic. 1.—Showing use of paraffin block and hydrometer cylinder for growing seedlings in nutrient solutions. and poured into a large cylindrical mold. This mold is best made out of some heavy paper and can be made of any desired diameter. After solidification of the paraffin within this mold, the various- sized cylinders can be cut off in much the same manner that bread 246 BOTANICAL GAZETTE [MARCH is cut. These cylindrical blocks can be made of any thickness, and by varying the size of the mold can be made of any diameter. To render the cutting of the paraffin more satisfactory, the mold can be placed at a temperature of 30-35° C., which will be sufficient to keep the paraffin in a pliable condition. Another method for securing these blocks which has given good satisfaction is to pour the hot water and paraffin into shallow pans, forming a layer of paraffin above the water of any desired depth, and then allowing it Fic. 2.—Seedlings in paraffin blocks suspended in water to show root development to solidify. From the circular layer thus secured, the desired blocks can be cut with various-sized cake cutters. The blocks of paraffin thus secured are then perforated in one of two ways. In the one the ordinary cork-borer is employed, using two of different diameters, making a perforation with the smaller through the entire block, and then with the larger borer through the upper portion of the block. In this way a perforation is secured with a small shelf upon which the germinating seedling can be placed. Equally satisfactory has proved the method of 1913] HOFFMANN—PARAFFIN BLOCKS FOR GROWING SEEDLINGS 247 using a piece of ordinary glass tubing which has been drawn out in a conical form. By pushing this through the paraffin a perforation is secured which is larger at the top and smaller at the bottom of the block, and which will prevent the seed from falling through into the liquid in which the paraffin blocks are to be suspended. In this manner one can make a support of any size and with as many per- forations as desired. These blocks when placed in the liquid culture medium serve automatically to keep the roots immersed ‘IG. 3.—Same seedlings as in fig. 2, but removed from water; far less differentia- tion in root dev elopment is evident. in the liquid, since they are free to rise and fall with variations in the level of the nutrient solution. This is impossible with a cork which fits snugly in the neck of the vessel, unless one continually restores the water lost by transpiration and evaporation. The size of the block, as well as the perforations, will depend entirely upon the seedlings to be grown, making them large for peas and corn, and small for wheat and clover. The blocks thus Prepared can be floated upon the culture medium in which the seedlings are to be grown, and, as already stated, will rise and fall 248 BOTANICAL GAZETTE [MARCH with changes in the elevation of the nutrient solution. Sufficient bulk must be given to the blocks to provide for the increased weight resulting from the growth of the plant. The most suitable receptacle for floating these block cultures has been found in the form of an ordinary hydrometer cylinder which has the enlargement at the upper portion of the cylinder. This is well shown in the accompanying illustration (fig. 1). For photographic purposes of seedlings thus grown these floats with their burden are placed in large, flat, glass vessels similar to the rectangular museum jars which are now being employed. In this way the root systems are well distributed and give a photograph revealing any differences which may exist in the root development. A comparison of the two photographs submitted (figs. 2 and 3), the one taken as above described, the other after removal from the water demonstrates this feature very strikingly, and proves the advantages of photographing as described. This method of photo- graphing is considered worthy of employment where work of a similar nature is performed and presented. AGRICULTURAL BACTERIOLOGICAL LABORATORIES UNIVERSITY OF Wisconsin, Mapison, WIS. BRIEFER ARTICLES A SIMPLE REVOLVING TABLE FOR STANDARDIZING POROUS CUP ATMOMETERS (WITH ONE FIGURE) In connection with field work carried on during the past season the writer has had occasion to standardize nearly 70 porous cup atmometers of the type described by Lirvincston.t The necessity of exposing the various cups in a series to uniform atmospheric conditions during the standardizing process is readily comprehended, but the difficulty in securing such conditions can be fully appreciated only by those who have tried it. Livincston has recently described a rotating table for standardizing these instruments,? and so far as fulfilling the requirements is concerned this can scarcely be improved upon. The only objection to it is the amount of time and expense involved in its construction, an objection which may have considerable weight if what is needed is a makeshift contrivance for temporary or perhaps occasional use rather than a durable piece of permanent equipment. The writer has devised for his purpose a very simple type of revolving table which can be constructed from readily obtainable materials with very little labor and expense and which has proven very serviceable. This apparatus is shown in the accompanying photograph (fig. 1). It consists, in brief, of the front wheel of a bicycle suspended horizon- tally within a wooden framework; on the upper side of the wheel is laid a piece of thick cardboard, or pulpboard, to support the bottles; from the lower side of the wheel wooden vanes are hung perpendicularly; the wheel is then caused to rotate by means of an air current from an electric fan. For constructing the framework three-quarter inch pine . board is sufficiently heavy, and rigidity is insured by the use of braces at the angles; the dimensions are largely a matter of convenience and will naturally depend somewhat on the diameter of the wheel used, height of atmometers, size of vanes, etc.; the framework shown in the figure measures 36X 30X24 inches (inside height, inside width, and depth, respectively). For supporting the wheel two upright pieces are * Carnegie Institution of Washington, Publication No. 50. 1906. ?Plant World 15: 157-162. 1912. 249] [Botanical Gazette, vol. 55 250 BOTANICAL GAZETTE [MARCH used; one of these projects vertically upward from near the center of the base of the framework (see fig. 1) to a level somewhat less than half- way to the top; the other projects downward from the top of the frame- work, in line with the first, to a level somewhat less than halfway to the bottom; the distance between the two contiguous ends of these uprights should be slightly greater than the length of the wheel hub; both uprights should be firmly braced. The wheel is held in position between the two uprights by means of two iron “corner-braces”’ (which can be secured at any hardware store), in each of which one of the four screw holes has been bored large enough to fit the axle of the wheel. In adjusting the FIG. 1 wheel to position a corner-brace is first screwed vertically to the upper end of the lower upright; the wheel is set in this and then firmly fixed in place by means of the second corner-brace which is screwed to the lower end of the upper upright; any slight divergence of the wheel from the horizontal plane can be corrected later by tilting the entire frame- work. For vanes 8 pieces of light wood about 8X ro inches are used; these are attached to the spokes by means of screw-hooks, being hung at a slight angle to the radii of the wheel; they are tied to the rim at their upper edges and are further held in position by means of wooden strips tacked to their lower edges. This table will accommodate 20 or more atmometers. As a precaution against the possibly disastrous 1913] BRIEFER ARTICLES 251 effect of centrifugal force it is well to fasten a cord around the bottles after the manner shown in the figure. The velocity at which the table rotates can be controlled by regulating the position and angle of the fan with respect to the vanes. If the bearings of the wheel are properly adjusted and the table with its load carefully balanced, a speed of less than four revolutions per minute can be maintained. The direct air current from the fan should not strike the cups. Such a revolving table as the one here described was run in the writer’s laboratory almost continuously for nearly three weeks at a speed ranging from 4 to 20 revolutions per minute and gave no trouble what- ever. In order to determine the accuracy of the data obtained, a test series of 20 cups was operated under various conditions for more than a week, readings being taken daily. It was found that with the table revolving at a rate of 8 revolutions or less per minute the coefficients derived from the readings of consecutive days varied very little; for several days none of the cups showed a variation amounting to as much as one per cent, while the difference in evaporation between two standard cups amounted to less than 0.2 per cent. With increased speed, how- ever, the coefficients are apt to fluctuate, due to various causes.—G. E. NIcHoLs, Vale University. POISONING BY GINKGO Several botanists after dissecting the fruits of Ginkgo have developed what appeared to be ivy poisoning. As the juice of the Ginkgo produced an immediate irritation of the skin, it was suspected that the rash which developed the following day was due to this. Later tests proved this to be the case. The poison is in the outer fleshy layer. It does not affect all people, since the gardeners at Smith College and at Mount Holyoke College have never been poisoned by handling the Ginkgo fruits, but a gardener in Elyria, Ohio, who cares for a fruiting tree in the yard of Mr. Wixtram G. Suarp, writes that he is poisoned every fall by handling the fruits. The irritation produced is greater than that of poison ivy, and the infection spreads more persistently and is communi- cated from one person to another. Pustules rarely form, however, as in ivy poisoning, but there is a heavy red rash, attended by the formation of welts in severe cases.—ANNA M. Starr, Mount Holyoke College, South Hadley, Mass. CURRENT LITERATURE BOOK REVIEWS Parasitic seed plants In ies to place at the command of students and teachers the best known methods of growing parasitic seed plants and to encourage the introduction of these ee neglected organisms into botanic gardens, HEINRICHER’ has compiled from his wide experience a manual of explicit directions ee the culture of all the better known species. Most of the European and many of the foreign representatives of the Scrophulariaceae, Orobanchaceae, Con- vol aceae, Lauraceae, Santalaceae, Loranthaceae, and Rafflesiaceae are included in his rather extensive list, and in nearly every instance his sugges- tions are based upon personal experience extending over several years. His previous investigations of the peculiarities in the germination of the seeds of parasites (reviewed in this journal?) have been extended, and much valuable data collected on the time required for bringing the parasites to maturity, as well as to the particular host upon which each develops best. While many of these plants may be grown readily in the open ground, pot culture is recom- mended for others on account of the greater ease with which they may be protected from insects and other enemies. It is found that many of the green hemiparasites are not very exacting in their choice of a host, but in promoting vigorous and rapid development care is often necessary in selecting a host that will not by too vigorous growth exclude the sunlight from the foliage of the parasite. This would indicate that the dependence is here incomplete and ee carbohydrates are synthesized by the leaves of the parasite. HEIN- RICHER, however, does not rely upon this evidence alone to demonstrate that many of the green parasitic seed plants, particularly those of the Rhi- nanthaceae, obtain only water and nutritive salts from their hosts, but pro- duces what seems to be a most complete line of evidence in support of his contention that photosynthesis continues long after the evolution of the parasitic habit has begun. He presents evidence that the leaves of these plants are highly differentiated morphologically, possess abundant stomata, : * HEINRICHER, E., Die Aufzucht und Kulture der parasitischen Samenpflanzen. 8vo. pp. 53. Jena: Gustav Fischer. 1910. 2 Bor. Gaz. Mae, ae 3 HemnricHer, E., Die griinen Halbschmarotzer, VI. Zur Frage nach der assimilato: ihe eee der griinen parasitischen Rhineanthaceen. Jahrb. Wiss. Bot. 4'7:539-587. r910. 252 1913] CURRENT LITERATURE 253 show a periodicity in their starch content which coincides with the recurrence of daylight and darkness, that locally darkened areas of the leaf blade soon show a deficiency in starch content, and that when the stomata are closed with cocoa butter starch formation does not occur. Further it appears that shoots free from starch soon showed the presence of that substance if placed in sunlight in an atmosphere containing CO., but controls, also in sunlight but in an atmosphere without CO.,, pares no —— Support i is also given to the contention that many of these plants re their hosts by the fact that they will thrive as root parasites upon annuals which have no starch or sugar stored in their subterranean organs.—Gro. D, FULLER. Phosphorescence in plants Motiscu! has issued a second and enlarged edition of his work on phos- phorescing plants. The book is very simply and interestingly written, and brings up to date his own extensive work in this field as well as the work of _ other investigators. The first chapter answers negatively the question “are there phosphorescing algae ?”, and shows that such appearances are due to light reflection or to animals living on the algae. The second chapter gives the evidence for the existence of phosphorescence in marine Peridineae and for its absence in fresh water forms. The third chapter deals at length with the phenomenon in fungi, both Hyphomycetes and bacteria, and the fourth shows the relation of salts and temperature to the light production in bacteria. The fifth treats of the nutrition, phosphorescing, and growth of the light-producing fungi, and the sixth with the manner in which light is Produced. Phosphorescence is an oxidation process demanding a minima] though very small partial pressure of oxygen. There is no convincing evi- dence for any direct relation between respiration and ia ste much less for the latter being produced by the former. The living cell produces a substance, photogen, which phosphoresces in the presence of water and free oxygen. In the higher fungi and bacteria, in contrast to many animals, the Phosphorescing has never been obtained extracellularly. In chapter seven the author gives the spectra and other characters of the light produced by various fungi The bacterial light is of sufficient intensity and of proper quality to render photographic work possible by it as the sole source of light. It will cause heliotropic response in various seedlings and fungi, and lead to chlorophyll Production, detectable by the spectroscope though not sufficient for visible 8teening. The light is not capable of penetrating opaque objects, as some workers have probably wrongly claimed for light produced by various animals. In contrast to the situation with many animals, MoLiscH cannot discover any biological significance of light production in plants. The last chapter ee ScH, Hans, Leuchtende segue: eine physiologische Studie. viii+193. bls. 2. tis: 18. Teun: Gustav Fischer. 1912. 254 BOTANICAL GAZETTE {MARCH deals with the alleged phosphorescence in flowering plants, and concludes that the cases cited are either sheen or due to electrical phenomena (St. Elmo’s fire)—WILLIAM CROCKE MINOR NOTICES The nuclei of Protista.—The name “Protista,”’ applied by HAECKER to the lowest animals and plants, has failed.to receive general acceptance, even among zoologists, and the forms are found under both the protozoa and unicellular plants. In any consideration of the phylogeny of the nucleus these forms must be of great interest, because the nuclei of the metazoa and of the higher algae and fungi are too highly differentiated to throw much light upon such a subject as the origin of the nucleus. A paper by HARTMANS deals almost entirely with the nucleus of protozoa and its significance as the forerunner of the nucleus of the metazoa. Botanists working with the nucleus in the lower algae and fungi, and especially with — cannot afford to overlook this paper.—CHARLES J. CHAMBERLAIN Symbolae Antillanae.°—In continuation of this important work Pro- fessor URBAN in cooperation with several eminent specialists has issued the second and third fascicles of the seventh volume. There are included descrip- tions of approximately 300 new species, several varieties, and a few new combinations The following new genera are proposed: Sarcopilea of the ia Asclepiadaceae, Ja oeapeamente of the Scrophulariaceae, and Shaferocharis of the Rubiaceae.—J. M. GREENMAN. NOTES FOR STUDENTS Root-tubercles of non-leguminous plants.—In an extremely long and somewhat obscure article, which is not made any clearer by the vague illustra- tions accompanying it, PEKLO? gives an account of his studies of the organisms co all esetntial details. Prxkto finds in the cells of the root-swellings of A/nus and Myrica masses of filaments with more or less radial arrangement and termi- 5’ HARTMAN, MAx, Die Konstitution der Protistenkerne und al beneath fiir . die Zellenlehre. 8vo. pp. v+54. figs. 13. Jena: Gustav Fischer. 6 UrBaN, I., Symbolae Antillanae seu fundamenta florae ie peut. Vol. VII, fasc. 2, pp. 161-304, 15 June; fasc. 3, pp. 305-432, 1 October. Dc iu Fratres Borntraeger. 1912. 7 PEKLO, J., Die pflanzlichen Aktimonykosen. Centralbl. Bakt. Il. 273451-579- 1910. 1913] CURRENT LITERATURE 255 nating in the peculiar vesicles described by BRuNcHOoRST. Like BRUNCHORST, he regards these vesicles as sporangia and describes the fragmentation of their contents into angular “‘spores.” In the filaments themselves, which finally break up into segments, he finds deeply staining bodies described by SHrBATA, and which resemble the spores of bacteria. These are regarded as endospores, although in his subsequent cultural work he appears to have made no attempt to settle the question of the sporelike nature either of these bodies or of the fragments of the vesicles, by showing that they are capable of germination. In view of Surpata’s observation that these bodies as well as the filaments are completely absorbed by the host, it seems that an experimental attempt to determine their true nature would have been worth while, especially since the author seems to have found no difficulty in growing his organisms. The similar to those observed in the host cells. The indecisive results of the infection experiments, however, leave some doubt as to whether his cultures contained the causal organisms of the root-galls. From the resemblance of the root-gall fungus of Alnus and Myrica to the animal parasite Actinomyces, PEKLO, following a suggestion made by Surpata in regard to the fungus of Myrica, transfers these organisms to the genus Actinomyces, and rebrands the as hese All these organisms he believes are highly organized bact hae studying the root nodules of Myrica Gale finds that the bulk of the cortical tissue back of the meristem of :the growing apex of the young nodules is infected with bacteria. These are massed together in “infection threads” extending from cell to cell. The bacteria were obtained in pure cultures where they showed the characteristics of Pseudomonas radicicola. Cultures grown for seven days at 25° C. showed a fixation of 2.05 mg. nitrogen Per toocc. It was found that Myrica plants growing in sterilized soil deficient in nitrogen did not flourish unless they possessed root nodules. When plants free from root nodules and growing poorly were watered with a culture of the bacteria, nodules developed and the plants began to thrive. Fungus filaments are found in bn older parts of the galls, soapetines close to the bacteria-infected cells, but alt not hizal nature of these filaments which are the ompanians deccrihed by previous investigators, he believes that they ig nothing to do with the origin of the nodules or with nitrogen fixation. ss. SPRATT? confirms former observations of BotromLy, according to which ee root-gall organisms of A/nus and Elaeagnus is a bacterium identical with Pseudomonas radicicola. The organism occupies the young cortical tissues ee * Borromiy, W. B., The root nodules of Myrica Gale. Ann. Botany 26: 111-117. “IQI2. * Spratt, Ere: Rose, The morphology of the root tubercles of Alnus and Gensak aud the polymorphism of the organism causing their formation. Ann. Botany 26: 119-128. 1912. 256 BOTANICAL GAZETTE [MARCH in a manner similar to that of the organism of Myrica described above. Miss SPRATT also finds that under certain conditions, both in the root and in cultures, the organism gives rise to relatively large spherical bodies or coccus forms. This polymorphism seems to be the result of lack of nutrition. When nutri- ment is supplied they divide and become transformed into typical bacilli. It was also shown that the organisms from both plants were capable of fixing free nitrogen, thus confirming HILTNER’s observations.—H. HASsELBRING. Morphology of orchids.—VERMOESEN” has made a careful study of the development of the ovule in several orchids. He finds arising at the lines of fusion of the three carpels three longitudinal “primary placental protu- berances,”’ each of which is caused by the cailgaict: of a band of subepidermal tissue, usually appearing in cross-section as three cells (possibly from a single The lateral members of this band of cells continue to divide actively, in the median line growth is retarded, resulting in a bifurcation of the placental protuberance. Growth is further checked at various transverse levels, so that the ovary wall soon shows three double rows of small promi- nences, each with its isolated group of active subepidermal cells. These promi- ces now branch repeatedly to form the numerous ovulary filaments, each of which finally produces an ovule at its summit. All the steps of this process are initiated by the activity of the subepidermal cells, which retain the charac- ters of archesporial tissue The author’s main conclusion is that the primary archesporial cells are those which give rise to the original placental protuberance on the wall of the ovary, since this group of cells by repeated dichotomy gives rise to all the tissue within the branched placenta, funiculus, and nucellus. The steriliza- tion idea is extended to include all these organs. It is further held that each carpel originally produced on its ventral surface two marginal archesporial bands which have become fused with those of the neighboring carpels. The development of an eight-nucleate embryo sac from one megaspore of an “incomplete tetrad” and fertilization occur in the usual manner.— STER W. SHARP Dioecism in Epigaea.—The flowers of Epigaea repens were divided by Gray into two main groups: one with well developed stigmas and abortive stamens, and the other with small, poorly formed stigmas and well developed stamens. Both groups possess equally good ovaries and ovules, and both show stamens and pistils of various lengths. STeEvENs™ has undertaken to determine two points: (1) whether there is any real evidence of a heterostylic condition, and (2) whether the species is actually dioecious. He finds that 10 VERMOESEN, CAMILLE, Saree a l’étude de l’ovule, du sac embryonnaire, et de la fécondation dans les angiosperm La Cellule 27: 115-162. pis. 2. 1911. 11 SrevENS, NEIL E., Dioecism in sags trailing arbutus, with notes on the mor- phology of the seed. Bull. Torr. Bot. Club. 38: 531-543. jigs. 4. 1911. 1913] CURRENT LITERATURE 257 pollen from stamens of all lengths develops readily on the stigmas of all —— of pistil, provided the stigmas are of the well eee sort. From this knoblike haustorial outgrowth which extends into the tissue of the integument. —LeEsTER W. SHARP. Crown-gall.—In their account of the crown-gall of plants, Situ, Brown, and Townsenp® described the occurrence of secondary galls origi- nating at some distance from primary galls which had been produced by direct infection, and suggested that the secondary galls arose in some way from € primary galls, although the mode of origin was not clear at that time. This problem has now been solved by a histological study of the crown-gall by MITH, Brown, and McCuttocu.® They find that the secondary galls arise from strands of tissue which originate from the primary galls and make their way along the stem or leaf, usually in the region of the primary wood. The tumor strand apparently does not absorb the cells in its path, but makes its way by crushing and flattening them. Secondary galls arise at various points along the tumor strand. cross-section of a secondary gall developing in the leaf from a strand arising from a primary gall in the stem shows a stem structure with the woody elements greatly developed and regularly arranged like the secondary wood of a stem. If, however, a primary gall develops in the leaf as a result of direct inoculation, its structure is irregular. The tissue consists of an enormous development of parenchyma intermixed with irregular masses of tracheids. There is no distinct differentiation of parts as in the secondary galls arising from stem galls. The similarity which has been formerly pointed out between these plant galls and animal tumors leads the writers to consider the crown-gall apart from all other plant diseases, and to place it in the category of true tumors.—H. HASsELBRING. * Rev. Bor. Gaz. 52:75. 191t. * SmitH, Erwin F., Brown, NEtueE E., and McCuttocs, Lucia, The structure and development of crown gall; a plant cancer. Bur. Pl. Ind. Bull. 255. pp. 60. Sigs. 2. pls. 109. Igt2. 258 BOTANICAL GAZETTE [MARCH Comparative anatomy of stomata.—From an examination of over 30 species of seed plants, taken from widely scattered genera, WarNCKE* finds upon many very divergent forms of stomata upon the different organs. So marked is the diversity that in some instances each organ seemed to possess its own particular type. On the whole, however, stomata on stems and petioles are much alike and are usually larger and with thicker walls than those of foliage leaves. The most divergent forms are those occurring upon rhizomes and in the epidermis of the inner side of sheaths. The very different external conditions will at least partially account for the greater amount of submergence below the level of the epidermis, for the thicker cell walls of the stomata of more exposed organs, and for the tendency toward loss of function and suppression upon the submerged and subterranean parts, but it is quite inadequate to explain the occurrence of two such entirely diverse types as those found upon the outer and inner surfaces of the sheath of Zea Mays. As might be expected, a close relationship is found to exist between the type of stomata and the general outline of the epidermal cells. No phylogenetic sequence is revealed in the various forms examined; indeed, the investigator does not believe that Porscu’s is warranted in his conclusions regarding the phylogenetic importance of the types of stomata, since he compared as homologous the stomata of various organs now found to differ to a marked degree upon the same individual, and even, in a few instances, upon different parts of the same organ.—Gro. D. FULLER. Embryo sac of Crassulaceae.—In 1908 WENT described the ovule and embryo sac of the Podostemaceae, in which he found among other peculiarities an empty cavity or “Pseudoembryosack” extending from the base of the short sac to the chalazal region. This has led Miss RoMBACH™ to investigate the related Crassulaceae in the hope of throwing some light upon the signifi- cance of this peculiarity. Eight species were examined, which showed agree- ment in all essential features. A subepidermal cell of the very reduced nucellus cuts off one parietal cell and then divides to form four megaspores, the inner- most of which gives rise to an embryo sac of the ordinary eight-nucleate type. During the early development of the endosperm and embryo the base of the sac with the antipodals grows downward through a central strand of loose, elongated cells until it reaches the chalaza. The author believes that here are present side by side two processes: - the outgrowth of the embryo sac, and cavity formation by the nucellus. In the Podostemaceae it is supposed that the embryo sac formerly filled all the 4 WARNCKE, FREDERICK, Neue Beitrige zur Kenntnis der Spaltéffungen. Jahrb. Wiss. Bot. 50: 21-66. 1911. 5 —. O., Der Spaltéffungsapparat im Lichte der Phylogenie. Jena. 19°5- %6Rompacu, Sara, Die Entwicklung der Samenknospe bei den Crassulaceen. Rec. Trav. ck. ‘Nécslandads 4: 182-200. figs. 10. 1911. ROT UR op Rear ek Oe) Sa es. oe ee eee Se NES Stone | aad yen ere MEE Ise sen 5 TTS ree he Cee ee eee Wane an oe pentane Oyo i bak Peete = LS 1913] CURRENT LITERATURE 2509 4 cavity down to the chalaza, as in the Rosaceae, but for some reason, possibly as a result of the peculiar mode of life shown by these plants, the outgrowth process no longer occurs, so that the empty ‘“ Pseudoembryosack”’ remains. The Crassulaceae are thus regarded as transitional forms between the Podoste- maceae and the Rosaceae.—LESTER W. SHARP Antarctic lichens.—In 1909 DARBISHIRE” reported on the very extensive collection of lichens secured by the Norwegian polar expedition of 1898-1902 d ANSEN. In connection with this report it was shown that from the region including Arctic America, Greenland, Spitzbergen, and Iceland about 500 lichens have been recorded. A similar report has now been published by DarsisHirE® for the antarctic region, based upon the collection brought back by the Swedish antarctic expedition of 1901-1903. There are now known 534 lichens from the general antarctics (subantarctic America, South Georgia, and the true antarctic region), 145 of which were secured by the _ expedition, 34 of them being new species. The true antarctic region contains 106 known lichens. It is an interesting fact that the relation of arctic to alpine lichens is much greater than that of subantarctic American species to those of New Zealand. It is further obvious that the similarity of subantarctic to arctic species is less striking than that of antarctic to arctic species, 43 per cent of the antarctic lichens being found in the true arctics and not in temperate regions. The new species are distributed among 17 genera, Lecidia and Buellia having 5 each; Pertusaria, Aspicilia, and Verrucaria having 3 each; Bacidia, . re eee Parmeliella having 2 each. The remaining genera, each repre- by one new species, are Biatora, Thelotrema, sissy Caloplaca, enc Parmelia, Rinodina, Acarospora, and Chaetomium.—J. M. C. A new Williamsonia.—Srwarp® has studied petrified material of a Williamsonia from the Jurassic of Scotland, to which he gives the name W. Scotica. It proves to be an exceedingly interesting and suggestive form. . _ The most striking vegetative feature is the replacement of the usual scales (tamentum) of the Bennettitales by an abundance of very long hairs, such occur on Dioon edule and other living cycads. The sections of the stro- bilus, the first obtained of a Wéilliamsonia, are of special interest. The isporangiate character is problematical, since no stamens were evident and Natuorsr has shown that some species of Williamsonia were monosporangiate. en, *7 DARBISHIRE, Otto V., Lichens collected during the second Norwegian polar aR in 1898-1902. Publ. Soc. Arts and Sciences Kristiania. 1909. , The lichens of the Swedish antarctic expedition. Wiss. Ergebn. : Sea Sudpolar-Exped. IQOI~1903. 42 no. 11 (pp. 73). pls. 3. 1912. *9 SEWARD, A. C., A petrified Williamsonia from Scotland. Phil. Trans. Roy. Soc. London B. 203:101-126. pis. 9-12. 1912 260 BOTANICAL GAZETTE [MARCH The interseminal scales and megasporophylls (stalks bearing terminal ovules), however, are of the Bennettites type, but much simpler in structure, although some of the simplicity may be due to immaturity. It is refreshing to obtain the following statement from an English paleo- botanist: ‘‘The morphology of the Bennettitean flower is still a problem to be solved, and the attractive hypothesis that would have us regard this domi- nant group of the Mesozoic era as a guide to the evolution of the class which now occupies the pre-eminent position in the vegetable kingdom, requires to be substantially strengthened before it can claim to have solved the mystery of the origin of the flowering plants.” —J. M. C Cytology of seedless oranges.—Osawa” has ee a the cytological situation in the two seedless oranges known as the ‘ ington navel’’ (Citrus aurantium) and the ‘‘Unshu” (C. nobilis), iyo using C. trifoliata as a check species. After showing that spermatogenesis and oogenesis in C. trifoliata are as usual among angiosperms, he finds in both the seedless forms a strong tendency toward the disorganization of pollen mother cells and megaspores. In the “Unshu’’ there is every stage in the failure of pollen development from a failure in the differentiation of sporogenous tissue up to the reduction divisions. In the majority of cases, however, pollen grains are produced. In the “Washington navel,’ spermatogenesis in the majority ot cases does not proceed beyond the mother cell stage. In both forms oogenesis usually proceeds to the formation of megaspores and then fails. As some normal embryo sacs are produced a few seeds were obtained; and the usual failure of seeds is due chiefly to the failure of embryo sacs rather than of pollen grains, especially in the case of the “Unshu.” The chromosome numbers in this form are 8 and 16. In C. #rifoliata it was discovered that fertilization occurs about four weeks after pollination, and the fertilized egg divides three or four weeks after fertilization —J. M Pine-barrens of New Jersey.—A careful examination of geological evidence leads TAYLOR” to the conclusion that the pine-barrens of New Jersey coincide in distribution with the geological Beacon Hill formation, an area that as been uninterruptedly out of the water since the Upper Miocene, and has several times been more or less completely surrounded by water. This would make this plant formation by far the oldest in New Jersey. Its xerophytic character does not appear to harmonize well with such a theory, although the number of more or less endemic species would seem to demand a rather com- plete and extended period of isolation such as the submergence and glaciation 20 Osawa, I., Cytological and experimental studies in Citrus. Jour. Coll. Agric. Tokyo 4:83-116. fig. I. pls. 8-12. 1912. 2t TAYLOR, NoRMAN, On the origin and present distribution of the pine-barrens of New Jersey. Torreya 12:229~-242. 1912. 1913] CURRENT LITERATURE 261 ee | £f. ae, 7 of pevacent territory would afford. Th of non in the pine-barren flora would tend to indicate a plant formation of considerable antiquity. The species from the far north in the pine-barrens are explained as having come down with the advancing ice sheets and having become isolated in bogs such as were probably to be found in explanation of the peculiar flora of this interesting plant formation. —Geo. D. FuLLER Origin of maize.—Co.ins* has been attacking the problem of the origin of maize by extensive cultures of the different types of maize, teosinte (Eu- chlaena mexicana), and teosinte-maize hybrids, through a period of seven years. The current view is that maize was derived from its nearest wild relative, teosinte. CoLLins concludes that it originated as a hybrid between teosinte and an unknown grass belonging to the Andropogoneae, a grass which resem- bled the earless varieties of pod corn (Zea tunicata). In enumerating the pronounced differences between teosinte and pod corn, he calls attention to the fact that in practically every case the characters of maize are intermediate. The origin of the maize “ear” has always been an interesting question. Cours regards it as ‘ie homologue of the central spike of the staminate inflorescence, but the central spike is quite as anomalous as the ear, and to account for it may call for the fasciation of simple branches of the inflorescence. In this sense, therefore, both opinions as to - nature of the maize ear (central spike or fasciation) may be right.—J. M Influence of adult on seedling. the seedling structure of Persoonia lanceolata (Proteaceae) as a basis for the claim that the adult structure influences that of the seedling. The occurrence of polycotyledony among the Proteaceae is well known, a also the resem- lance in the habit of some of them to the gymnosperms. The number of cotyledons in P. /anceolata ranges from three to five, and the authors are con- vinced that they have arisen by the splitting of two original structures. The details of the seedlin ng structure further emphasize the close resemblance to the polycotyledonous gymnosperms, “a resemblance which is found not only in the general morphological configuration, but also in certain histological details and in the transition phenomena.” The authors, of course, attach no phylogenetic significance to these similarities, but ‘‘the resemblance is considered as a striking instance of momnasy s in which the adult has influenced to a considerable extent the seedling.” —J. M. C. * Cottins, G. N., The origin of maize. Jour. Wash. Acad. Sci. 2: 520-530. 1912. * Hitt, T. G., and DEFRamg, E., On the influence of the structure of the adult plant upon the miciliivie. New Phytol. 11: 319-332. figs. 9. 1912. 262 BOTANICAL GAZETTE [MARCH ascular anatomy of Ophioglossaceae.—Lanc™ has been investigating the vascular anatomy of the three genera of Ophioglossaceae, and in advance of the publication of the full papers he has made a brief statement of his con- clusions. It is becoming apart evident that the Ophioglossaceae are true ferns, and this return to the earlier views as to their relationships is emphasized by the present paper. The critical study of the anatomy of the in plan of stelar construction between the Ophioglossaceae and the Coeno- pterideae” (Botryopterideae and Zygopterideae). There are also features in common with the Osmundaceae and Hymenophyllaceae. When one considers the gaps in our knowledge of the extinct forms, it is safer to suggest relation- ship i in a general way than to be too Specific, and this attitude LANG has taken. He is convinced, further, that in the O p develop saesiotelat pith.—J. M. C. Vegetative reproduction in Angiopteris.—It has been known for a long time that the leaf stalk of Angiopteris is differentiated into two regions, a basal portion bearing stipules, and a midrib bearing pinnae, the two regions being separated by an abscission layer. From material in the garden and from a study of large specimens in the forest, VAN LEEUWEN% records the following observations: the foliage leaf persists for about two or three years and then breaks off at the abscission layer, the leaf base remaining many years longer; after the leaf has fallen, four resting buds appear on the leaf base, and when it finally falls off, one or more of the buds begin to grow and many develop into new plants. CIBORSKI first noticed such buds in Angiopteris; the present account gives additional information from plants growing under natural conditions.— CHARLES J. CHAMBERLAIN. Fossil prothallia—_McLEan™ has added to our meager knowledge of paleozoic prothallia by describing two female prothallia from the Lower Coal Measures of England. One is that of the classic Lagenostoma Lomaxii, and it resembles closely the female gametophyte of modern gymnosperms, the radial arrangement of the tissues suggesting centripetal growth by “alveoli.” This radial arrangement is lacking in such a gametophyte as that of Lepidocar- pon. The other gametophyte is that of Bothrodendron, one of the lycopods. It is extremely well preserved, and strongly resembles the emergent and 24LanG, Witt1am H., On the interpretation of the vascular anatomy of the Ophioglossaceae. Mem. and Proc. Manchester Lit. and Phil. Soc. 56: no. 12 (pp. 14). Jigs. 6. 1912. 25 VAN LEEUWEN, W. Docrers, Uber die vegetative Vermehrung von Angiopieris evecta Hoffm. Ann. Jard. Bot. Buitenzorg 10:202-209. pl. 18. 1912 76 McLean, R. C., Two fossil prothalli from the Lower Coal icinlies New Phytol. sie gig-ark: ‘hes: 2. pls. 5, 6. 1912. 1S Ae ona ree oe rae 1913] CURRENT LITERATURE * 263 flaring gametophyte of the water ferns, with the archegonia developed outside the spore. Since the female gametophyte of Lepidocarpon remains entirely within the megaspore, that of Bothrodendron represents a more oe condition, in which the gametophyte is partly free from its spore.—J. M Id air drainage.—In investigating the physical factors influencing the distribution of vegetation in the Santa Catalina Mountains, SHREVE” has ound important differences in the temperature limits of stations at similar altitudes, but differently related to the ridges and valleys of the mountain slopes. These differences are shown to be due to valleys and cafions being frequently occupied by a stream of cooled air, and to amount to a difference in the mean minimum temperature equivalent to that usually experienced with an increase in altitude of 2350 feet. The influence of this cold air drainage seems to be most important in its effect upon the upward distribution of low- land species, and will do much to account for the higher range of these species upon the ridges and upper slopes of cafions.—G£o. D. FULLER. Botryopterideae.—Licnier*® has investigated Stauropteris Oldhamia, nd its eae UO ey 2 ee ‘ + which h £ e ne terid Following the theory of the meriphyte, and including the sporangial structures, he reaches the conclusion that Stauropteris does not belong to the Coeno- pterideae, which represent an advanced group, but very near to the more primitive Primofilices. Incidentally he presents a “genealogical tree,”’ which m have give r Coenopterideae (Botryopterideae) through Stauropteris as a start; (2) to the Marattiaceae through Archaeopteris and Botrychium, with a possible side branch wii to a Leptosporangiates; (3) to the Pteridosperms (Cycado- filicales).—J. M ardizing atmometers.—The difficulties involved in subjecting a Standar considerable number of atmometer cups to exactly similar conditions of temperature, humidity, and air movement for the period of time necessary for their standardization has caused LrvincsTon® to devise a table rotating once per minute by means of a small electric motor belted to a reducing gear. The cups, mounted in suitable bottles, are placed near the outer margin of the table, and should a very high rate of evaporation be required an electric fan is made to furnish a current of air crossing the table. As the efficiency of the atmometer is largely dependent upon the accuracy of its standardization this device will prove helpful to ecological workers.—Gro. D. FULLER 7 SHREVE, Forrest, Cold air drainage. Plant World 15:110-115. 1912. 8 LIGNIER, O., Le Stauropteris Oldhamia Binney et les Coenoptéridées la lumiére de la théorie du ee Bull. Soc. Bot. France 59:1-33. Jigs. II. 1912. 9 Livincston, B. F., A rotating table for standardizing porous cup atmometers. Plant World cat ae 1912. 264 BOTANICAL GAZETTE [MARCH Water relations of plants.—In order to make clear the complex relation- ships which determine the moisture content of the growing plant and more especially to emphasize the artificial character of the distinction usually made etween the organism and its environment, LivincsTon® has prepared an excellent schematic representation. It should prove a valuable aid to teachers .of ecology and plant physiology in presenting this difficult topic. The gene theory of physical causation is made to apply to all the organic phenomena involved.—Gro. D. FULLER Habitats of the red cedar.—Harper,*" in seeking for an explanation for the occurrence of Juniperus virginiana in very diverse habitats, finds one w he deems satisfactory in the sensitiveness of the tree to fire. Its prevalence upon limestone soils is noted and the conclusion is reached that “the cedar dreads fire more than it likes lime,” and that it is found chiefly in areas which are rarely visited by forest fires. No experimental data are offered in support of this conclusion.—Geo. D. FULLER. A new Jurassic fern.—THomas:? has described from the Jurassic of England a new species of the Stachypteris of PoMMEL (1847). In studying the affinities of the genus, he concludes that the structure of the sporangia and of the fertile spikes does not indicate any close affinities with the modern groups of ferns, but that it must belong to “‘a group of ferns intermediate in their characters between the Cyatheaceae and the Schizaeaceae.”—J. M. C. Embryogeny of R ] In continuing his studies of the embryo of Ranunculaceae, SovEGEs%3 has published a detailed account of the em- bryogeny of Adonis. The preceding parts have dealt with the Clematideae* and with Myosurus.35 In Myosurus the Aaa of events is very constant, while in Adonis it is very variable—J. M. C. 3° Lrvincston, B. E., A schematic representation . - water relations of plants; a pedagogical suggestion. Plant World 15: 214~218. 1 3t HARPER, R. M., The diverse gas of the eastern aa cedar and their inter- pretation. Rosrevs 12: 145-154. I 3 Tuomas, H. HamsHaw, Sth Hallei, a new Jurassic fern. Proc. Cam- bridge Phil. Soc. 16:610-614. pl. 33 SouEGES, R., Recherches sur Fas: des Renonculacées. Anémonées (genre Adonis). Bull. Soc. Bot. France 59: 474-482, 545-550. figs. 224-269. 1912. 4 Bot Gaz. 512480. 1911. 3s Bot. GAz. 543264. 1912. lume LV Number 4 BOTANICAL GAZETTE Editor: JOHN M. COULTER April ro1r3 The Effect of Certain Chlorides Singly and Combined in Pairs on the Activity of Malt Diastase Lon A. Hawkins A Physiological ent: Chemical Study of After-Ripening Sophia Eckerson » The California Paroselas | S. B. Parish The Effect of Some Puget Sound Bog Waters on the Root Hairs of Tradescantia Sood B. Rigg Current Literature The University of Ghicees Press CHICAGO, ILLINOIS, U.S.A. Agents _ THE CAMBRIDGE UNIVERSITY PRESS, London and Edinburgh WESLEY & SON, London : TH. STAUFFER, Leipzig ne THE 4 Tokyo, Suse Kyote Che Botanical Gazette A Monthly Journal Embracing all Departments ot Botanical Science Edited by JoHN M. CouLTErR, with the pastas of aus members of the botanical staff of the Uni y of Chic Soca: er 15, = Vol. LV CONTENTS FOR APRIL 1913 | No. 4 Baar eh OF CERTAIN CHLORIDES SINGLY AND seen kt IN PAIRS ON ACTIVITY OF MALT DIASTASE. Lon A. Hawkin A at wes, of ab AND CHEMICAL STUDY OF AFTER-RIPENING. ConTRIBUTIONS M THE Hut BoTANIcaL Laporarory 170. Sophia Eckerson THE CALIFORNIA PAROSELAS. (wits FIVE Figures). S. B. Parish eet, San ee THE uti OF SOME PUGET SOUND BOG WATERS ON THE ROOT HAIRS OF TRADESCANTIA. George B. Rigg - - oot ek Sony he CURRENT LITERATURE BOOK REVIEWS’ 2 = Pe Se Ee RRR TE see rr THE ECOLOGY OF WATER PLANTS. PLANT BREEDING IN SWEDEN... THE COTTON. PLANT. MINOR NOTICES A ao oe mone tk : a - g - : one a ae “WOTES FOR STUDENTS. ree re ee ee ee ge ee is $7. of cs copies is 75 cents. 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A table ped apptoximate cost of additional se ae e ng posted on an pat blank whi accompani ies the proof; a copy will be sent on request. : . _ Ente Aug oat the Ps afc at Chic, wml Smt At Cn Me aw umbers should be made within the month following the a month of niet VOLUME LV NUMBER 4 THE DOTANICAL GAZETTE APRIL 1913 THE EFFECT OF CERTAIN CHLORIDES SINGLY AND COMBINED IN PAIRS ON THE ACTIVITY OF MALT DIASTASE! Lon A. HAWKINS The effects produced by single inorganic salts in aqueous solu- tion upon an organism and the modification of these effects by the presence of other salts has been the subject of considerable research. It has frequently been found that a definitely toxic influence of one Salt may be completely removed by the addition of a second salt, itself also markedly toxic when used alone. This mutual counter- action by salts of the toxic influence of each other has been termed antagonism. While single’ salts and their combinations do not, of course, affect all organisms in the same way, yet different investigators have shown antagonistic salt action in the case of Many organisms and with many chemical compounds. Thus, Loew? demonstrated that the i injurious action of certain concentra- tions of magnesium nitrate upon Spirogyra majuscula is inhibited by the presence in the medium of a proper amount of calcium nitrate. Similarly Logs? found an antagonism to exist between the nitrates of calcium and of sodium in their influence upon the * Botanical contribution from the Johns Hopkins University. No. 23. * Loew, O., Uber die physiologischen Functionen der Calcium- und Magnesium- Salze im Piteneendeginianne. Flora 75:368-304. 1892. 3 Lors, J., Studies on the physiological effects of the valency and possibly the electrical charges of ions. I. The toxic and antitoxic effects of ions as a function of their valency and possibly their electrical charge. Am. Jour. ~~ 6411-433. | Tg02, ste 266 BOTANICAL GAZETTE [APRIL development of the eggs of Fundulus; and OsTERHOUT,’ working with plants, has shown the same kind of antagonism between the . salts of magnesium and of potassium. That caJcium and potassium influence each other in their effect upon certain bacteria has been brought out by Lipman.’ In a theoretical consideration of the possible causes of chemical stimulation, it is suggested that, since many vital phenomena seem to be dependent upon enzymes, it is possible that the influence of chemical substances upon the activity of plants and animals may be due in some measure to the action of such substances in accelerating or retarding enzyme activity. With these ideas in mind, it was undertaken to study the relation between the catalytic action of some enzyme and the concentration in the medium of certain salts, to determine, if possible, whether enzyme catalysis is influenced independently by two salts simultaneously present in the medium, or whether either salt increases or decreases the accelerating or retarding influence of the other upon such catalytic reactions. __ The studies here reported bear upon this question and were carried out in part in the new Laboratory of Plant Physiology of the Johns Hopkins University, at Homewood, and in part in the Biological Laboratory of the Johns Hopkins University. The writer is greatly indebted to Professor BurToN E. LIvINGSTON, under whom this investigation was conducted, for his many helpful suggestions and criticisms. Materials The enzyme chosen for investigation was, for practical reasons, malt diastase (Merck’s ‘diastase of malt absolute’’), and the salts used were chlorides of sodium, potassium, calcium, magnesium, copper, and iron (Kahlbaum’s ‘‘chemically pure” salts were exclu- sively used). The activity of the diastase was measured in terms of the length of time required for it to render a starch paste (of washed maize starch) powerless to give color reactions with iodine. 4OsterHout, W. J. V., The antagonistic action of magnesium and potassium. Bot. GAz. 45:117-124. 1908. . Pe e ‘7 1 14 mmont fication by Bacillus subtilis. Bor. Gaz. 48: 105-125. 1909. 1913] HAWKINS—MALT DIASTASE 267 All water used was distilled from glass and condensed in a well seasoned glass condenser. The various pieces of apparatus coming in contact with the solutions or mixtures of the experiments were carefully cleansed in this water before use. Method The method here employed for determining the duration of hydrolysis is similar to that described by SHERMAN, KENDALL, and CLARK as the liquefaction method for estimating diastatic activity.® The exact procedure in the present study was as follows: A sufficient quantity of starch for the entire study was purchased at one time and thoroughly mixed. Of this material 2.5 grams were weighed out, placed in a porcelain dish, and by means of a glass rod rubbed into a suspension with a little water. This mixture was then diluted to a volume of 500 cc., boiled two minutes, and then strained through cheesecloth, thus making a o. 5 per cent starch paste, a homogenous Equid which flows freely and is easily measured from a burette. With the exception of a small amount used in preliminary tests, all the diastase for the investigation was purchased at one time and thoroughly mixed to insure uniformity. It was preserved in a glass-stoppered bottle and showed no signs of deterioration during the several months the study was in progress. A 2 per cent solution of this diastase was prepared in much the same manner as that employed in making the starch paste. Two grams of the dry material were first thoroughly suspended in a small amount of water and then diluted to a volume of 100 cc., after which the solution was filtered. Fresh diastase solution and also fresh Starch paste were prepared at the beginning of each experiment, to preclude the possibility of error resulting from the growth of Microorganisms. No antiseptic was used in the various mixtures. Stock salt solutions, sufficient in quantity for the entire study, were prepared at the beginning of the investigation, in concentra- tions of I-4 gram molecules per liter of solution, and from these _ the requisite dilutions were made. The iodine solution used in the tests was originally prepared in quantity sufficient for the whole °Suerman, H. C., Kenpatt, E. C., and Ciark, E. D., Studies on amylases. I. An examination of methods for the determination of diastatic power. # aod Am. Chem. Soc. 32:1073-1087. 1910; references to here 268 _ BOTANICAL GAZETTE [APRIL research in a concentration of 1.5 grams of iodine and 3 grams of potassium iodide per liter of water. In experimentation the various mixtures were placed in large test tubes (30 mm. in diameter and 150mm. deep), which were suspended through the suitably perforated top of a cylindrical water-bath. The water of the bath stood always at a higher level than that of the liquid in the tubes, which were some distance apart, the outer ones being several centimeters from the walls of the bath. It was thus assured that the mixtures in the tubes were maintained at the same temperature as the surrounding water. The temperature of the bath was kept nearly constant at 50° C., by means of an ordinary mercury regulator and a gas flame below. The variations in temperature were between the limits of 48° and 52°. Since the computations of the velocity of diastatic activity were always made in terms of the velocity of the reaction in controls within the same series, the possible effects of temperature fluctua- tions should be exceedingly slight. A series of mixtures was usually prepared in the following manner: In each of a series of tubes was placed the proper amount of salt solution at a concentration in each case of four times’ the required concentration for each particular tube. To this were added 5 cc. of water, in the cases where the action of a single salt was to be tested, or an equal quantity of the solution of the other salt, in those where salt combinations were to be used; 8 cc. of starch paste (o.5 per cent) were then added to each tube, followed by 2 cc. of the previously prepared diastase solution. The tubes, containing 20 cc. of mixture, were immediately placed in the water- bath. It is thus apparent that all test mixtures contained the same quantity (0.2 per cent or 0.004 gm.) of the starch and of the diastase. An experiment was usually made up of (1) a series of 7 different concentrations of some salt used singly; (2) a series of 7 different concentrations of another salt used singly, and (3) a series, usually in duplicate, of the 7 concentrations of the two salts in binary combinations. These with the two control tubes made a total of 7 For 2m mixtures ro cc. of the 4m stock salt stincasond wer Placed in Eee ~— this when diluted to 20 cc. by the addition of the st g concentration of the salt. 1913] HAWKINS—MALT DIASTASE 269 30 tubes to be tested at one time. The control tubes were prepared in exactly the same way as the others, except that water was sub- stituted for the salt solution. In order to determine whether or not the salt solutions alone had any appreciable hydrolytic effect upon the starch, tubes were frequently made up with the salt solution and starch content the same as those in the experiment but without the diastase. These were placed in the water-bath together with the other tubes and tested from time to time in the usual manner, but in no case was there any variation from the typical blue color of the starch-iodine reaction. It was thus clear, as was to be expected, that while the salts could influence the velocity of the action of the diastase on starch, they were themselves apparently incapable of any appreciable hydrolytic action. To determine whether the contents of any given tube had teached the end point, a single drop of the stock iodine solution was placed in each of two small vials (ro mm. in diameter and 70 mm. high). To one vial was added 1 cc. of water and to the other a like quantity of the mixture from the proper tube, carefully pipetted out. The two vials were then observed against a white background in diffused light, and if their contents appeared to be of the same color (a pale yellow) the experimental end point was considered to have been attained. It has been found that by this method of determin- ing the end point, the color produced in a starch paste containing but 0.0002 of 1 per cent can be readily detected. This sensitive- ness lies well within the limits of error of the other operations of the experiments. Final failure of one of the starch-diastase mixtures to produce color (blue, purple, red, brown, etc.) does not necessarily mean that all of the original starch content has been converted into a reducing sugar, but merely that all of the starch has been so altered as to be no longer able to form colored com- pounds with iodine—showing that one or several of the steps of the process of hydrolysis have been completed. In this connection it may be remarked that Lanc® has shown with pancreatic amylase that the amount of a reducing sugar present at the time when the starch paste first fails to color with iodine does not represent and G, S., Uber die Einwi der Pank f Stirkearten verschie- denen Heskoatt Zeitschr. Exper. Path. u. Therapie 8: 279-307. 1910. 270 BOTANICAL GAZETTE {APRIL is not proportional to the original amount of starch. The present investigation is therefore not directly comparable with such investi- gations as those of KjELDAHL,? KELLERMAN,”? McGuIcaAn," and others, who measured diastatic activity by determining the amount of a reducing sugar formed in a given time. For a more complete bibliography on the effects of salts on diastatic action, the reader is referred to EFFRONT,” GREEN,™3 OPPENHEIMER," EULER," as well as to the literature cited here. Experimentation The water, diastase, and starch used in this work were tested for neutrality in the course of the investigation, and it was found that while the water and starch-paste were neutral to phenolph- thalein, the diastase solution was strongly acid, requiring 1.2 cc. of o.or normal hydrate to neutralize 2 cc. of the stock solu- tion. Thus each tube of mixture as actually used possessed an acidity equivalent to 1/1660, or 0.000602 normal. Several series were carried out by neutralizing or partially neutralizing (with sodium hydrate) this acidity of the diastase, and a strong retarda- tion was evident when even a small quantity of the alkali was added. Thus the use of 5 cc. of 0.0005 alkali diluted to 20 cc. by the addition of the usual amounts of diastase solution, starch- paste, and water (reducing the acidity of the mixture to 0.000477 normal) caused a retardation of 13 per cent as compared with the control without the alkali. With a further decrease in the acidity to 0.000352 normal, there was apparently but little action of the diastase, and when the original acidity was completely neutralized, 9 KyELDAHL, Recherches sur les ferments producteurs de sucre. Compt. Rend. Lab. Carlsberg 1: 109-157. 1879 % KELLERMAN, Kart F., The effects of various chemical agents upon the starch- converting power of taka diastase. Bull. Torr. Bot. Club 30:56-70. 1903. ™ McGuican, H., The relation between the rg corned of salts and their antifermentative properties. Am. Jour. Physiol. 10:444-451. 1 EFFRONT, JEAN, Enzymes and their applications. SR s ae New York. 1902 %3 GREEN, J. REYNOLDS, The soluble ferments and fermentation. Cambridge University Press. 1901. 14 OPPENHEIMER, Kart, Die Fermente und ihre Wirkungen. Leipzig. 1910. 15s EuLer, Hans, Allgemeine Chemie der Enzyme. Wiesbaden. 1910. hate eo: oo 1913] HAWKINS—MALT DIASTASE 271 no alteration in the starch could be detected by the iodine test, after a peed of 5 hours in the water-bath. Ad tion of the resistances of the starch and diastase solutions by means of a Wheatstone bridge and the calcula- tion of corresponding conductivities showed the presence of a small quantity of electrolytes in the mixture. These must have modified to: some extent the effect of the addition of the different salts in the experiments. Since, however, the same con- centrations of starch and diastase were employed throughout the investigation, the electrolytes originally present are to be considered as constant in quantity. Furthermore, the concentrations of the salts used were usually comparatively high, so that any resulting errors due to what may be termed electrolytes of impurity (or of constitution) of the mixture used must be relatively slight. It was observed in many cases that, in mixtures containing salts at the higher concentrations used, a flocculent precipitate was gradually formed during the experiment. This precipitate was isolated and gave no starch reaction with iodine. No relation could be detected between its occurrence or amount and the diastatic activity. It seems, therefore, that the effect of the presence of a salt in increasing or decreasing diastatic activity cannot be due to a salting out from the solution of either diastase or starch. This is in accord with the conclusion reached by Core” in his work on ptyalin, but contrary to what might seem to be the case from the investigations of Harpy.’?7 In this connection it is interesting to note that Munrer®™ has recently shown that many of the salts of the alkalies and alkaline earths are ineffective for the precipitation of the diastase of Aspergillus oryzae. Testing was begun when the mixtures had remained in the water-_ bath one hour, and was continued thereafter at intervals of 15 minutes until the conclusion of the experiment. Thirty or more LE, S. W., Contributions to our knowledge of the action of enzymes. Part I The influence of electrolytes on the action of amylolytic ferments. Jour. Physiol. 30: 202~220. I ™ Harpy, W. B., A preliminary investigation of the conditions which determine the stability of seca hydrosols. Proc. Roy. Soc. London 66:110-125. 1900. 8 Munter, F., Uber Enzyme. Landwirtsch. Jahrb. Erganzband III. 39:298- 314, 1910. ; 272 BOTANICAL GAZETTE [APRIL similar vials were prepared before each test, each with its drop of iodine solution, and the samples were consecutively pipetted into these from the tubes, following the order in which the diastase had been originally added. The pipette was thoroughly washed after each use and thoroughly clean vials were always employed. The number of minutes which elapsed before the end point was reached for each mixture was recorded, thus furnishing a means for the quantitative comparison of the enzyme activity under the differ- ent conditions. For example, a series of 2, 1/2, 1/8, 1/32, 1/128, 1/512, and 1/2048 molecular sodium chloride gave for the respective TABLE I EFFICIENCY OF DIASTATIC ACTION AS AFFECTED BY VARIOUS CONCENTRATIONS OF s AND POTASSIUM CHLORIDES, SINGLY AND COMBINED SINGLE SALTS (Mol 1 pam ) ms I:I NaCl : KCl olecular proportio: Concentration . Concentration 4 Total salt con- : tk waetare Efficiency ta wieture Efficiency centration in Efficiency va 2m <. 51 2m 1.77 m/2 eg m/2 2.19 Mol. 1.38 m/8 1.82 m/8 1.61 /4 1.93 /32 1.42 /32 1.39 m/16 1.92 m/128 0.85 m/128 0.85 /6 1.07 m/512 0.95 m/512 0.93 m/256 0.89 m/2048 I.02 m/2048 I.00 m/1024 0.96 time periods 165, 165, 150, 180, 315, 285, and 300 minutes, the control mixture (without any added salt) reaching the end point in 285 minutes.’? The intensity of the enzyme action in experi- ments such as these is, of course, for any given mixture reciprocally proportional to the number of minutes required for that mixture to reach the end point. Thus the ratio of the time period of the control to that of any mixture is obviously a measure of the velocity of the hydrolysis for that mixture in terms of the velocity of the control. Thus, the relative velocities or intensities of starch hy- drolysis for the experiment just cited become, respectively, 285/165, 19 The time periods for the two control tubes were the same in all series except - three, and in these cases the two results (differing but slightly) have been averaged. 1913] HAWKINS—MALT DIASTASE 273 285/165, 285/150, 285/180, 285/315, 285/285, and 285/300, Or 1.73, I.73, 1.90, 1.58, 0.90, 1.00, and 0.95, when the ve- locity of the reaction without added salt is taken as unity | TABLE II EFFICIENCY OF DIASTATIC ACTION AS AFFECTED BY VARIOUS CONCENTRATIONS OF SODIUM AND CHLORIDES, SINGLY AND COMBINE SINGLE SALTS hapeiaauitas Glace proportions, NaCl CaCl NaCl 2:CaChL 1) : Total salt con- Boy Efficiency | Concentration | Eésciency centration in Efficiency mixture 2m ret Mol. Retardation 3m Retardation m/2 t.3F ~ m/4 £2393 3m/4 1.21 m/8 1.82 m/16 2.80 3m/16 3-29 /32 1.42 /6 3.69 3m/64 3.40 m/128 0.85 m/25 3.01 3m/256 2.75 m/512 0.95 m/1024 1.88 3m/1024 1.85 m/2048 1.03 m/4096 1.07 3m/ 4096 i.17 TABLE III EFFICIENCY OF DIASTATIC ACTION AS AFFECTED BY VARIOUS CONCENTRATIONS OF IUM AND MAGNESIUM CHLORIDES, SINGLY AND COMB: SINGLE SALTS ComsrnaTIons (Molecular proporti 8 oe pen ons, NaCl MgCl: NaCl 4:MgCh 1) i : Total salt con- ie ay Efficiency ye es omer Efficiency centration in Efficiency 2m 1:2 m/2 Retardation | 5m/z2 Retardation m/2 t.91 m/8 25 5m/8 m/8 1.82 m/32 2.07 5m/32 1.90 /32 1.42 m/128 1.97 5m/128 2.21 m/128 0.85 m/512 1:35 5m/512 1.54 m/512 0.95 m/2048 1.07 5m/2048 0.89 m/2048 1.02 m/8192 1.00 5m/8192 0.99 These numbers may be termed the ratios of the enzyme activity or of efficiency. Such a computation as the foregoing has been made in each case, always with the enzyme activity of the control for the particular experiment in question taken as unity, and it 274 BOTANICAL GAZETTE [APRIL is with the efficiency ratios for the diastase in the presence of the various concentrations of the different salts that this paper has to deal. These ratios should be comparable throughout the entire TABLE IV EFFICIENCY OF DIASTATIC ACTION AS AFFECTED BY VARIOUS CONCENTRATIONS OF SIUM AND CALCIUM CHLORIDES, SINGLY AND COMBINED SINGLE SALTS CoMBINATIONS (Molecular proportions, KCl CaCl: BCI 3:CaCh2) iris Total salt con- ig 2 ogg Efficiency ow Efficiency centration a Efficiency 2m 5.77 Mol. Retardation | 3m Retardation m/2 2.19 m/4 1.33 3m/4 1.24 m 1.61 m/16 2.80 3m/16 2.73 m/32 1.39 m/64 3.69 3m/64 2.87 m/128 0.85 m/256 3.01 3m/25 2.87 m/512 ©.93 m/1024 1.88 3m/1024 2.13 m/2048 I.00 m/4096 1.07 3m/4096 eae | TABLE V EFFICIENCY OF DIASTATIC ACTION AS AFFECTED BY VARIOUS CONCENTRATIONS OF TASSIUM AND MAGNESIUM CHLORIDES, SINGLY AND COMBINED SINGLE SALTS PO ge aeuetianh KCl MgCl. KCl 4:MgCh 1) ‘oncen' : Total salt con- bas sore gg Efficiency gp eg Efficiency centration n in Efficiency —_ 1.77 m/2 Retardation | 5m/2 Retardation m/2 2.19 m/8 2.25 5m/8 1.07 m/8 1.61 m/32 2.07 5m/32 1.83 m/32 1.39 m/128 1.07 5m/128 2.07 m/128 0.85 m/512 1.35 5m/512 1.20 m/512 0.093 m/2048 I.07 5m/2048 1.12 m/2048 1.00, m/8192 1.00 5m/8192 1.08 study; where they are less than unity the salt or salts have exerted a retarding influence upon hydrolysis; where they equal unity the salt treatment has been without effect; and where they are greater than unity the effect of the salts has been to accelerate the 1913] HAWKINS—MALT DIASTASE 275 action of the enzyme. Of course the combination treatments possess a total salt concentration equal to the sum of the two indi- vidual concentrations of the single salts which have been combined. TABLE VI EFFICIENCY OF DIASTATIC ACTION AS AFFECTED BY VARIOUS CONCENTRATIONS OF AGNESIUM AND CALCIUM CHLORIDES, SINGLY AND COMBINED SINGLE SALTS Comanrartons . (Molecular proportions, MgCl CaChL MgCl 1:CaCh 2) Total salt con- 7 ma year org Efficiency —— Efficiency centration rn Efficiency m/2 eae Mol. Retardation | 3m/2 Retardation m/8 2.25 m/4 1.33 3m/8 1.06 /32 2.07 m/16 2.89 3m/32 3.06 m/128 1.97 /64 3.69 3m/128 3-61 m/512 1.35 m/256 3.01 3m/512 2.65 m/2048 1.07 m/1024 1.88 3m/2048 2.09 m/8192 1.00 m/4096 1.07 3m/8192 1.16 TABLE VII EFFICIENCY OF DIASTATIC ACTION AS AFFECTED BY VARIOUS CONCENTRATIONS OF C AND CUPRIC CHLORIDES, SINGLY AND COMBINED SINGLE SALTS : CoMBINATIONS (Molecular proportions, r:1) Fe,Cls CuCL Co: tratio: : : : Total salt con- " in, an — Efficiency a Efficiency german in Efficiency m/1024__| Retardation m/1024_ | Retardation [512 Retardation m/2048 1.45 m/2048 3.50 m/1024 | Retardation m/4096 3.55 m/ 4096 2.62 m/2048 3.17 /8192 3-91 m/8192 1.26 / 4096 3-59 m/16,384 1.98 / 16,384 1.00 m/8192 {| ~—si1..92 m/32,768 1:87 m/32,768 1.00 met 384 1.45 m/65,536 1.00 m/65,536 1.00 m/32,768 1.00 The total salt concentrations for the several combinations are given in the tables. It was impracticable to combine 2m NaCl with 2m KCl, so this combination was not tested. The molecular Proportions at which any two salts were combined are clear from 276 BOTANICAL GAZETTE [APRIL the concentrations of the single salts standing in the same line with the datum for the combination, but these proportions are stated at the head of the columns of combinations. In those cases where the word “‘retardation”’ occurs in the efficiency column, this denotes that the efficiency here is much below that of the control without added salt, the end point not having been reached at the close of the experi- ment in question. EFFECT OF SINGLE SALTS From the foregoing tables it is apparent that all the salts used in this investigation, at some concentrations (both singly and in combination), increase the rate of hydrolysis over that of the control without added salt; at certain other concentrations they retard this process; and at still others they have apparently no influence on diastatic activity as measured in this study. Thus, with the chlorides of sodium and potassium, used singly, it may be seen that with a concentration of m/2048 the effect is practically the same as in the control with distilled water. An increase in salt content, however (to m/512), results in a slight retardation of diastatic action; while with a further increase of added salt (to m/128), the point of maximum retardation, as found in this investigation, is attained. All higher concentrations used, of these two salts, accelerate hydrolysis, the points of maximum acceleration being at a concentration of m/8 for sodium chloride and of m/2 for the potassium salt. Possibly the most striking feature of the results shown in table I is that retardation apparently occurs only at relatively low concentrations. To supplement the evidence obtained from the experiments, that-there was a retardation with . m/128 sodium chloride and potassium chloride as here employed, five additional series were carried out with the two salts singly at this concentration accompanied by the required controls without added salt, all made up and tested in the usual manner. In every case a marked retardation was evident in the mixtures containing the salts, as compared with the controls. This retardation cannot be due to a partial neutralization of the acidity of the diastase by small amounts of free alkali present in the salt solutions (the latter were very slightly alkaline to phenolphthalein), for table I shows that still higher concentrations of these two salt solutions, containing propor- tionately more alkali, unquestionably accelerate diastatic activity. 1913] HAWKINS—MALT DIASTASE 277 So far as the writer has been able to learn, such retardation with dilute concentrations of sodium and potassium chlorides has not been recorded heretofore. KuEBEL,?° working with saliva, showed a slight decrease in the acceleration of hydrolysis at low concentra- tions of these two salts, but found no retardation such as is shown in table I, m/128 being the most dilute solution he used. This writer found a maximum acceleration between m/32 and m/128 for these two salts, and a retardation with high concentrations. He used a colorimetric method for determining the velocity of hydrolysis, comparing with tubes of colored liquids the various colors. produced by the addition of iodine after a given time period. It is possible that results thus obtained may not be comparable with those of the present investigation, as the time intervals of transition between the different colored dextrins and between the last colored product formed, and achroodextrin may not be in the same proportion when the enzyme is activated by a salt as when no salt is added. Of course it must also be remembered that KUEBEL’s enzymatic mixture was saliva, while that here studied was barley diastase. GRUTZNER,™ using the same method of estimating diastatic activity as did KursBet, but working with pancreatic amylase, found the optimum concentration of sodium chloride to be between m/8 and m/32. For dialyzed ptyalin Cote found a slight decrease in the accel- eration with m/3000 sodium chloride, though acceleration at this point was still considerable. He found the point of maximum accel- eration to lie between m/4 and m/300. Experiments have been carried out upon the effect of sodium chloride on diastatic action by other investigators, with varying results. Calcium and magnesium chlorides, used singly, affect hydrolysis somewhat differently from the two monovalent salts. A decided retardation is evident at high concentrations, molecular for the calcium salt and m/2 for that of magnesium. This is in marked , F., Uber die Einwirkung verschiedener chemischer Stoffe auf die ete yr Mundspeichels. Archiv fiir die gesammte Physiologie 76: 276-305. 2* GRUTZNE 2 Uber die Einwirkung verschiedener chemischer Stoffe auf die Thatigkeit des tiectechen Pankreasfermentes. Archiv fiir die gesammte Physiologie 91°195-207. 1902. 278 BOTANICAL GAZETTE [APRIL contrast with the strong acceleration evident for sodium and potas- sium chlorides even at much higher concentrations. The points of maximum acceleration for calcium and magnesium chlorides, as here determined, occur at a concentration of m/64 for the former and of m/8 for the latter. From these points the acceleration falls with the gradual decrease in salt content to m/4096 calcium chloride, which accelerates but slightly, and to m/8192 magnesium chloride, which is apparently without influence. No retardation at low concentrations, as in the case of the monovalent salts, is here apparent. The effect of the salts of the heavy metals on diastatic action (with the possible exception of mercury) have not received as much attention as those of the alkalies or the alkaline earths, which are so uniformly present in the environment of most organisms. From table VII it is apparent that the chlorides of iron and copper, as used in this investigation, retard diastatic action markedly even when present in very smal] quantities. Acceleration occurs in very dilute solutions, as compared with the accelerating concentrations of the other salts, the region of acceleration being found to lie between con- centrations of m/2048 and m/8192 for cupric chloride, and between those of m/2048 and m/32,768 for ferric chloride, with maximum accelerations at m/2048 and m/8192, respectively. WOHLGE- MUTH,” working with salivary diastase, found that colloidal solu- tions of these metals in comparatively dilute concentrations retarded diastatic action. He did not find the strong accelera- tion which is so apparent in the present investigation, possibly because of the fact that his metals were in colloidal condition, or because of the few concentrations that he employed. Accord- ing to the data here presented, calcium chloride appears to be exceptionally effective in accelerating diastatic action, which is in accord with the findings of LisBonNE,” working upon the effect of this salt in restoring the activity of dialyzed salivary and pan- creatic amylases in the presence of demineralized starch. 23 WOHLGEMUTH, J., Untersuchungen iiber Diastasen. Biochem. Zeitschr. 9: 10~- 42. 1908. 23 LISBONNE, MArcet, Influence des chlorures et de phosphates sur la sacchari- fication de l’amidon déminéralisé par les amylases salivaire et pancréatique. Compt. Rend. Soc. Biol. 70: 207-209. 1911. ES eg Se 1913] HAWKINS—MALT DIASTASE 279 In the present study with ferric chloride, at a concentration of m/4096 an acceleration was found slightly higher than any obtained with the various concentrations of copper and of calcium. It is interesting to note here the high concentrations of copper that are favorable to diastatic action, in comparison with the great toxicity of this salt toward plants as observed by KAHLENBERG and TRUE,”4 STEVENS,”> DuGGar,”® LIvVINGSTON,”’ and others. A comparison of the different degrees of the acceleration of diastatic action resulting from the presence of the various salts used singly brings out the point that the effects of potassium chloride and of sodium chloride are much the same; which is in agreement with the work of KUEBEL, GRUTZNER, COLE, WOHLGE- MUTH, and others, for extract of pancreas and salivary diastase. Calcium chloride, as shown in the tables, accelerates more than do the salts just mentioned and also more than does magnesium chloride. This is not in accord with the results of WoHLGEMUTH, who, however, used only a single concentration of calcium and magnesium chlorides, this being the optimum concentration for sodium chloride as he found it, a consideration which probably accounts for the discrepancy here mentioned. EFFECT OF SALT COMBINATIONS The average ratios of diastatic efficiency furnish a means for attacking the problem which led to the present studies, whether or not two salts simultaneously present in a mixture influence each other’s effects on starch hydrolysis. While the data obtained in these experiments are not sufficiently complete to warrant. quantitative consideration of this problem, several points are at least qualitatively indicated. It is apparent that, since different concentrations of the same salt produce markedly different-effects * KAHLENBERG, Louis, and TruE, RopNey H., On the toxic action of dissolved salts and their electrolytic dissociation. Bot. Gaz. 22:81-124. 1896. *s STEVENS, F. L., The effect of aqueous solutions upon the germination of fungus Spores. Bor. Gaz. 26:377-406. 1898. UGGAR, B. M., vhanieoees ree nore ae reference to the germination of certain fungus spores. Bort. Gaz. 31:38-66. 190 77 LIVINGSTON, Burton Pa peeran i of a green alga. Bull. Torr. Bot. Club 32:1-34. 1905. 280 BOTANICAL GAZETTE [APRIL upon the process of starch hydrolysis, any single treatment may be regarded as a combination of two separate applications of the salt in question, each at a lower concentration. The data above pre- sented show that increasing the concentration of any salt almost never results in a proportionately increased effect upon hydrolysis. Sometimes such an increase completely reverses the direction of the effect, as when an increase in the concentration of sodium chloride from m/128 to m/32 produces an alteration in the efficiency ratio fromo.85to1.42. Another example of this is furnished by calcium chloride, for which a change in concentration from m/4 to molecu- lar is accompanied by an alteration of the salt effect on diastatic action, from 33 per cent acceleration to a quantitatively undeter- mined, but nevertheless exceedingly marked, retardation. In most cases increased concentration of a single salt does not change the direction of the effect, but simply alters its intensity, as when an increase in the concentration of sodium chloride, from m/8 to m/2, results in decreasing the acceleration of hydrolysis from 82 to 71 per cent. It is to be expected, therefore, that the bringing of two different salt treatments into combination may frequently result in the same sort of effect as that produced by increasing the con- centration of one of the single salts, the total salt concentration remaining the same as before. This is the true condition of affairs in many instances, and the specific question which confronts us— without attempting any precise quantitative comparisons—is whether combinations of two salts produce more or less effect upon starch hydrolysis than would either salt alone, at the higher con- centration that obtains in the combination. Put in another way, the problem is this: if a portion of the amount of a given salt in a diastase mixture be replaced with a molecularly equal amount of another salt, is the resulting alteration in the effect upon hydrolysis merely that traceable to dilution of the first salt together with that due to addition of the second (as would be expected if the combined treatments were without effect upon each other), or is this alteration of a different character? Despite the incomplete- ness of the data at hand, study of the tables brings out several points bearing upon this question, which are made still more clear if graphs are resorted to. The more striking of these points will now be mention ae es fe 3 pee i fee eee Ee ape ee oN ee eee eee ee een ee . 1913] HAWKINS—MALT DIASTASE 281 In the case of the two monovalent salts, with concentrations in the region of m/16 (where the accelerating influence of the single salts is marked, without attaining its maximum), the acceleration of diastatic action produced by combination (molecular propor- tions 1:1) is notably greater than that produced by either single salt. At the highest concentration used (m), however, the reverse of this proposition holds, and the combination is not as favorable to diastatic action as are the single treatments. The four series of combinations involving sodium chloride or potassium chloride with the chloride of calcium or magnesium generally show efficiencies which follow somewhat closely those for the bivalent salt of the combination: With combinations of sodium and calcium chlorides (molecular proportions 2:1; equiva- lent proportions 1:1), in lower concentrations (where the calcium salt alone accelerates more markedly than does that of sodium) the efficiencies, higher than for the sodium salt alone, are not as high for the combination as for calcium chloride alone. In concentrations from 3m/64 to 3m/16 the combination results in greater accelera- tion than does either single treatment. Combinations of sodium chloride and magnesium chloride (molecular proportions 4:1, equivalent proportions 2:1) show no cases where the tendency to accelerate hydrolysis is pronouncedly greater than that resulting from one of the single salts. It is best here, for the most rapid hydrolysis, to use magnesium chloride In lower concentrations (where it alone accelerates more) and to use sodium chloride in higher concentrations (where this salt accelerates more). In concentrations of the region of m/32 the efficiencies for calcium chloride alone are markedly greater than for the combina- tion of this salt with potassium chloride (molecular proportions 2:1; equivalent proportions 1:1), although the partial concentra- tions of the latter salt, when singly applied, possess a decided accelerating effect. At the concentration 3m/16, diastase efficiency for the combination used is greater than for either salt alone at Concentrations nearest 3m/16. The relations which held for combinations of potassium chloride and magnesium chloride (molecular proportions 4:1; equivalent 282 BOTANICAL GAZETTE [APRIL proportions 2:1) are similar to those which obtain for combinations of sodium chloride with the magnesium salt. It appears that the combination is here never more favorable for starch hydrolysis than the single salt treatments. In combinations of magnesium chloride with calcium chloride (molecular proportions 2:1) the efficiencies appear to follow those of the calcium salt, the magnesium in this combination seeming to have acquired as great efficiency for the acceleration of hydrolysis as that which characterizes the portion of the other salt which it replaces. - With combinations of copper chloride and ferric chloride (molecular proportions 1:1) the efficiencies’ generally lie between those for the single-salt treatments of the same concentration, as though the effectiveness of the combination were the mean influence of the two component partial treatments. No increased efficiency - is here brought out by replacing’ a portion of one of these salts with a molecularly equal portion of the other. While the considerations just presented appear to lead to the conclusion that certain concentrations of salt combinations may favor greater diastatic activity than do the same concentrations of either salt alone, yet it is obvious that sufficient information is not yet at hand to allow any attempt at generalization. The suggestion becomes patent that the study of properly balanced salt combina- tions, in their relation to enzymatic action, may add much not only to our knowledge of this persistently vague province of physiology, but also to our ability to control these important processes. THEORETICAL CONSIDERATION OF RESULTS In connection with the general problem of the nature of. the acceleration and retardation of diastatic action by electrolytes, the results of the investigations of Coxe deserve careful considera- tion. In a research carried on with dialyzed ptyalin, this author formulated a hypothesis to account for the influence of electrolytes on enzyme action, which to quote him directly is as follows (0?- cit. p. 211): “The hydrolysis of starch by ptyalin is accelerated by the presence in the solution of electronegative ions (anions) other than hydroxyl ions and depressed by the presence of electro-. 1913] HAWKINS—MALT DIASTASE 283 positive ions (kations) and by hydroxyl ions.” He considers the effect of electrolytes on the rate of action to be compounded of two factors: (1) “the acceleration due to the anion; (2) the depression due to the kation.”” The work of this author showed that the addition of a small quantity of hydrochloric acid to a chloride in optimum concentration for diastatic hydrolysis did not result in an added acceleration, but in a decreased activity. This he accounted for by considering the acceleration produced by the chloride as due to the chlorine ions, these being already in optimum concentra- tion before the addition of the acid; hence when more chlorine ions were added with the acid there could be no further increase in diastatic activity. The observed decrease in enzyme efficiency, which accompanied the putting in of the acid, was explained as due to the increased concentration of retarding cations which must result from the presence of the acid and to the destruction of ferment by the hydrogen ions. The salt present in a molecular condition is not taken into consideration. This hypothesis appears to explain many of the phenomena of salt influence upon diastatic action as found in these studies. It does not, however, offer an explanation for the retardation of diastatic action by low concentrations of sodium and potassium chlorides. Coe suggests also that all cations seem to retard diastatic action alike, which would seem questionable from the standpoint of the results obtained in the present investigation. WouLGEMUTH, investigating the effects of certain salts on the hydrolysis of starch by pancreatic amylase, using a colorimetric method for determining the rate of hydrolysis, concludes that the acceleration caused by a chloride is due to the chlorineion. BANc,* working with dialyzed ptyalin and determining the amount of a reducing dextrin formed from soluble starch in a given time, as a measure of the rate of hydrolysis, agrees with WOHLGEMUTH in this. McGutean, working with malt diastase and using as a criterion for comparing the different salt effects the inhibition of the forma- tion of any reducing sugar in a certain time period, takes a view Opposite to that of Corr. He considers the acceleration of enzyme 8 Banc, Ivar, Untersuchungen iiber Diastasen. Biochem. Zeitschr. 32:417-442. II 284 BOTANICAL GAZETTE [APRIL action brought about by a salt as due to the effect of the cation and the retardation as due to the anion. Although his results are not directly comparable to those of the present investigation, it may be noted that most of the salt effects here brought out may be explained by this theory about as satisfactorily as by that of COLE. It is manifestly impossible, however, from the evidence brought out in this investigation, to decide whether either theory is adequate to explain satisfactorily the phenomena of acceleration and retarda- tion of diastatic action by electrolytes. It is, of course, probable that diastatic action is, in some measure, affected by the presence of salts in a molecular condition, also that certain salts form compounds with the enzyme itself, or with other organic bodies which are present in the diastatic mixtures that have usually been used in experimentation of this sort. Likewise diastases of different origins may be influenced quite differently by the same electrolytes. Further and more careful experimenta- tion, with refinement of methods as suggested by Forp,?? SHERMAN, KENDALL and CLARK, FRANKEL and HAmBurG,* and others, are still much needed. Summary The present investigation deals with the effects of sodium, potassium, calcium, magnesium, cupric, and ferric chlorides, alone and in certain binary combinations, on the hydrolytic activity of Merck’s “‘diastase of malt absolute,” the enzymatic mixture acting on a boiled solution of washed maize starch, at 50° C. The dis- appearance of the ability of the starch to give a color reaction with lodine was taken as the end point of the reaction, and the reciprocal of the time period which elapsed before this end point was attained (considering the time period of the control without added salt as unity) was used as a measure of the intensity of enzyme action. A wide variation is clearly shown in the influence of the differ- ent, chlorides upon diastatic action, which is probably to be related to the properties of the various cations employed. More or less 29 Forp, Joun S., Lintner’s soluble starch and the estimation of diastatic power. Jour. Soc. Chem. Ind. 23:414-422. 1 39 FRANKEL and Hampurc, Uber Diastase. Beitr. Chem. Physiol. u. Path. 8: 389-308. 1906. 1913] HAWKINS—MALT DIASTASE 285 pronounced acceleration of starch hydrolysis is shown for all of the salts used at different concentrations; the highest acceleration found is for iron (291 per cent) and the next highest for calcium (269 per cent). Retardation of hydrolysis is shown at high con- centrations for all salts excepting sodium chloride and potassium chloride. For these two salts a pronounced retarding action (15 per cent in both cases) is manifest at low concentrations, the great- est retardation occurring with concentration m/128. This retarda- tion in-weak solution seems not to have been considered heretofore. Combinations of two salts are shown to be sometimes more and sometimes less efficient in modifying diastatic action than are molecularly equal concentrations of their component salts. It is thus possible that enzymatic power, the magnitude of which is frequently to be related to the concentration of single salts in the medium, may in some cases at least be still more highly devel- oped than is possible through the influence of single salts, by the presence of a properly balanced salt combination. Jouns Hopkins UNIVERSITY BALTIMORE, Mp. A PHYSIOLOGICAL AND CHEMICAL STUDY OF AFTER-RIPENING CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 170 SopHiA ECKERSON Many seeds and spores require a long time for germination. The term “after-ripening’”’ has come into rather genera] use to designate the changes in the seed during this period. It is often loosely used to include disintegration of the seed coats as well as protoplasmic or metabolic changes in the embryo. It seems better to limit its use, as has been done in this laboratory, to those cases where the delay is due to characters of the embryo. In the majority of seeds thus far investigated, the delayed germination is due to the exclusion of water or of oxygen by the seed coats. A few seeds have been studied, however, which do not grow when all coats have been removed and the embryo put in good germinating conditions. Some change within the embryo is necessary before germination, that is, lengthening of the hypocotyl, can take place. This process is what we mean by “after-ripening.”” Nose and HANLEIN (45), WIESNER (52), Jost (29), and others assume, in cases where water enters the seed coat, that growth after a long period is due to some change going on within the embryo during the seemingly dormant period. This has been determined definitely for only three or four species. Lakon (35) finds that the delayed (1-2 years) germination of Pinus silvestris, P. Strobus, and P. Cembra is not due to coat char- acters. With the coats broken or removed, the time required for germination was not shortened. Seeds of Fraxinus excelsior (36) sown in the spring do not germinate until the following spring. _ In the mature seed the embryo occupies about half the space within the endosperm; the rest is occupied by a mucilaginous substance. During the year that the seed lies in the ground, the embryo grows in length and fills the seed coat. Since the embryo is fully matute at maturity of the seed, but a period of growth is Gazette, vol. 55] [286 1913] ECKERSON—AFTER-RIPENING 287 necessary before germination, LaKon calls this ‘‘ Vorkeimung” instead of ‘‘ Nachreife.”’ Many methods have been used by different workers in the attempt to shorten the resting period of buds and bulbs. The first of these is JOHANNSEN’S (30) treatment with ether. He found that growth could be hastened at the beginning of and near the end of the resting period, but not in the middle period. Motiscu (40) immersed shoots in water at 35° C., and the buds opened earlier than those on untreated shoots. IraKtioNow (23) finds that the warm bath increases respiration only in the first days, then the respi- ration curve falls to its original height. Mi.iter-THuRGav and SCHNEIDER-ORELLI (42, 43) used the warm bath method to hasten the germination of potato tubers, and lily of the valley bulbs. They find the sugar content increased by the warm bath, but this is immediately used by the increased respiration. Unless the bulbs are kept at a high temperature, there is no lasting effect. Zero temperature increases the sugar content and the respiration; injury produces a slight increase in sugar content. They do not believe that hastened growth in these cases is due to increased sugar content, but rather that the high temperature has some effect on the protoplasm. CHRISTENSEN (3) made chemical analyses of resting and growing bulbs, but found no appreciable differences. He concluded that the slow growth of resting bulbs was not due to lack of soluble food materials. WEBER (53) and JESENKO (27) found that injury to the buds hastens their development. Later, JEsENKO (28) found that the shoots from these buds were abnormal. Shoots immersed in dilute solutions of alcohol, H,SO,, and other substances, develop normally and more rapidly than untreated shoots. Laxkon (37) forced the development of winter buds by standing the cut ends of shoots in Knop’s solution. Mottscu (41) has recently found radium emanations effective. All these various methods shorten somewhat the rest period of bulbs and winter buds. Little has been done to determine what is the limiting factor to growth in these cases and what internal change is produced by the external application. CROCKER (4, 5) found that the long period required for germina- ee, 288 BOTANICAL GAZETTE [APRIL tion of seeds of hawthorn is due in part to seed coat characters and in part to characters of the embryo. With testas removed, in light at room temperature, the cotyledons increase greatly in size and turn green, but only a small percentage (2-5 per cent) of the hypocotyls grow. Davis and Rosse (6), working in this laboratory, studied further the germination of seeds of Crataegus mollis. They find that under ordinary conditions seeds with carpels intact require one year or more for germination. Embryos with carpels removed, but with testas intact, germinated after 90-96 days at 5-6° C.; 74 per cent germinated after 75 days in the cold when removed to the warm greenhouse. With both carpels and testas removed, after 28 days at 6° C. 78 per cent germinated in 5 days in the greenhouse. Thus with all coats removed there is still a delayed germination due to characters of the embryo itself, a period of ‘‘after-ripening” necessary before elongation of the hypocotyl can take place. It has been my purpose to study the changes within the embryo during this period. Investigation I have made a preliminary microchemical study of the chemical changes during after-ripening. These results form the basis for a quantitative study. This paper gives the results of the micro- chemical study, together with quantitative determinations of the substances in the embryo at different periods during after-ripening. Davis and Rose (6) found the best conditions for after-ripening to be a temperature of 5-6° C. This inhibits growth of the cotyledons and is favorable for the metabolic changes within the hypocotyl. I studied the after-ripening of several species Seeds with testas intact were soaked 16 hours at 5° C., were washed thoroughly by shaking in a bottle of distilled water (to prevent mold), and put in dishes on moist cotton in the ice chest at 5-6° C. Microchemical tests were made once a week during the after-ripening period. Sections were preserved in glycerin for comparison. 1913] ECKERSON—AFTER-RIPENING 289 MICROCHEMICAL METHOD In order to detect the metabolic substances of the cell as nearly unchanged as possible, observations must be made on the living tissue. Sections were made on a freezing microtome or free- hand, and intra-vitam stains (8) were used. Of the different ‘methods and stains used, the following were found to be the most valuable. Fats.—Soudan III or Scharlach R, dissolved in 50 per cent alcohol. All fats are soluble in these stains. Lecithin.—The fats were first dissolved out with acetone, in which lecithin is not soluble. It was then stained with Soudan IIT, or blackened with fumes of osmic acid. Starch.—The sections were first heated in water on the slide, and then a drop of iodine solution added. Sugar.—For the reducing sugars Fehling’s solution was used as follows. The sections were heated in the copper sulphate solution, on the slide. The other part of Fehling’s solution, Rochelle salt and sodium hydroxide, was then added. Copper oxide is deposited in the cells containing sugar. Still better is the osazone test as modified by Mancuam (38). Dissolve phenylhydrazine hydrochlo- ride and sodium acetate in 10 times their weight of glycerin; warm to dissolve; filter once or twice. To use, put a drop of each on the slide, mix, put section of tissue in same. Place slide in warm oven : 5-30 minutes, and then cool. Osazone crystals will be formed in the © cells which contained sugar. ' Acidity or alkalinity—Neutral red, sulphate of Nile blue, Dahlia violet, and methyl orange. A 1/5000 solution of neutral ted is sensitive to N/11,000 NaOH; a 1/5000 solution of sulphate of Nile blue is. sensitive to N/s100 NaOH; the others are less Sensitive (Q). Catalase.—A drop of H,O, was put on the section on the slide and evolution of oxygen noted. Oxidase.—A few drops of freshly made solution of guaiaconic acid, on the slide. : Peroxidase.—A drop of H,O, added to a few drops of guaiaconic acid, put on the sections on the slide. BOTANICAL GAZETTE [APRIL Acidity Cot. acid Great in- crease x Hyp. basic Oxidase ° x Peroxidase Hyp. little crease x Cot. x “crease Slight in-| Great in- x Catalase Starch ie} Sugar Trace TABLE I CONDITION OF THE EMBRYO OF CRATAEGUS GLORIOSA Protein Lecithin Fatty oil Abundant Condition of seeds Air-dry ripened At germina-| Decrease tion After- Glucoside amygdalin i ee The value of neutral red as an indicator has been questioned by many. If the change in color of a dye is due to H ion content, it can safely be used as an_ indicator. FRIEDENTHAL (13) gives a very valu- able series of indicators with the H or OH ion concentration which will produce a change in color. In the presence of substances which form combinations with the dye, the change in color would be no indi- cation of H or OH ions. In all my work, however, the acidity or alka- linity as shown by neutral red was confirmed by titrations with NaOH or HCl. Microchemical tests should be fol- lowed always by quantitative de- terminations at the critical points. When so used the method is reliable and is a great saving of time and material. RESULT OF MICHROCHEMICAL TESTS The condition of the embryo at the beginning and end of the after- ripening period, and at germination just after the hypocotyl has pushed out through the testa, is shown in the accompanying table (I). In all the tables, x indicates presence in quan- tity, and o indicates absence. There is a very gradual, though constant, increase in the acidity and in the enzymes during the whole period. After 80-90 days at 5°C., 1913] ECKERSON—AFTER-RIPENING 201 when the acidity has almost reached its maximum, the fats begin to break up and sugar appears. Oxidase first appears at this time. Hydrocyanic acid appears after 75 days, increases up to germina- tion, then decreases (19, 49). WATER-HOLDING POWER Since the hypocotyls of the air-dry seeds are basic, while the cotyledons are acid, it was thought that they might have less ability to take up water than the cotyledons. To test this, seeds were taken at different stages of after-ripening, the coats removed, and the naked embryos soaked in water for 5 hours. These were then dried carefully with filter paper and, after the hypocotyls were separated from the cotyledons, were put in separate weighing bottles. These were weighed, then heated in an oven 10 minutes at 100° C., removed from the oven, and dried at 50° C. Many determihaticis were made. The accompanying table (II) gives a typical series. TABLE II WATER-HOLDING POWER OF EMBRYO OF CRATAEGUS GLORIOSA Hypocoryis COTYLEDONS , Wet Dry Percentage 4 = Percentage water weight pe “ water. Wet Dry weight weight grams grams Coats removed and soaked Ste 0.0157 | 0.0121 23 0.2690 | 0.1542 42 90 ‘ays ae Co 0.0189 | 0.0116 | 38 | 0.2700] 0.1744| 35 Germinated (hyp. 3mm.)..| 0.0289 | 0.0115 60 0.2094 | 0.1260 39 ACIDITY Determinations of acidity were made at the same periods o after-ripening as the water determinations (table III). ae embryos were washed in distilled water which had been boiled to expel CO,,. It will be seen that the metabolism of the fats does not begin until the acidity has reached a certain amount, the water content has increased greatly, and the enzymes are set free. The hypocotyl does not elongate until that time. It has long been known that 292 BOTANICAL GAZETTE [APRIL considerable free fatty acid is formed during the germination of oily seeds (GREEN 17, SCHMIDT 50). MILLER (39) finds, in the germi- nation of Helianthus annuus, that the quantity of free acid in the hypocotyl increases rapidly at the beginning of germination. IvANow (24, 25, 26) studied the metabolism of fats in ripening and in germinating seeds. He finds that the rapidity of oil trans- formation in germinating seeds depends on the fatty acid com- ponents of that particular oil. The oil of flax and of hemp contains TABLE III ACIDITY OF EMBRYO OF CRATAEGUS GLORIOSA Hypocoryis | COTYLEDONS NT/ N/20 ou! N/20 KOH Grete 1/0.) cocper Grams |N/ af pues cc. per gram Hs gram WAAL erica se 0.0267 | Slightly | 0.00 | Air-dry | 0.5374 | 0.20 0.37 basic es Re ee ee eee oer O:10 ‘| 30 days |< 52 6.5. ae 0.40 Se er eb ee ea cau O30 Wi ess a3 3% oo 2 ae 0.0444 | 0.04 °.90 | Cots. 0.8162 | 0.35 0.42 white 24 Oni) ek: 0.360 0.45 t.24 | Cots. 0.1914 | 0.60 3-13 yellow Germinated (hyp. OOF oy os 2. 0.5967 | 0.65 1.09 | Cots. 0.3907 | 1.20 3-07 green (in light week) es ee 0.3810 | 0.60 ey es 1: 7009" | 1.90 2.67 the less saturated acids—linolenic and linoleic—and is trans- formed much more quickly than that of rape, which contains oleic acid. The less saturated acids disappear rapidly (forming carbo- hydrates) from the seedlings and cause the very low acid number of flax and hemp. Unsaturated acids of the oleic acid type are more stable and inactive; therefore rape shows a higher acid num- ber than flax or hemp. The acids in the seeds of Crataegus were not identified; this will be done later. DELEANO (7) studied the chemical changes during the germina- tion of Ricinus communis. He finds that the acidity and the 1913] ECKERSON—AFTER-RIPENING 293 catalase increase up to a maximum, which is reached on the eighth day of germination (the hypocotyl is then 2.5 cm. long). Then the fats begin to break up and within two or three days disappear. The fats are transformed into a soluble substance of the character of a plant mucilage. This is later transformed into sugar, cellulose, and other substances. DELEANO says that the acids activating hydrolysis are formed during germination; he detected acetic and lactic acids. He thinks that catalase is directly concerned with hydrolysis of the fats. This is doubtful, however, since catalase is so universally present. Peroxidase reached a maximum about the fourteenth day of germination (the hypocotyls were 8.5 cm.). The chemical changes during the 90 days of after-ripening of Crataegus are the same as those of the first 8 days of germination of Ricinus. It is as though the chemical processes, telescoped in Ricinus, are drawn out in Crataegus. Seeds of the crab apple (Pyrus baccata) after-ripen in 30 days ats°C. At the beginning of their after-ripening period, hypocotyls of these embryos have an acidity and a water-holding power slightly greater than those of Crataegus after 60 days at 5° C. (hypo- cotyl 1.45 cc., N/2o KOH, moisture 48 per cent; cotyledons o. 368 cc., moisture 39 per cent). Peroxidase increases gradually from a very little in the air-dry seeds to a considerable amount at germina- tion. As in Crataegus, oxidase does not appear in hypocotyls of Pyrus baccata until immediately before germination. EFFECT OF ACIDS FiscHER (11) finds that when seeds of water plants (Alisma, Sagittaria, and Sparganium) are treated with dilute solutions of acids, or the strong alkalies KOH and NaOH, the percentage of germination is increased. He conceives the H ions of the acids, and the OH ions of the alkalies as destroying the equilibrium of the cell and starting up the chemical processes.' Seeds treated with Solutions of the fatty acids (formic, acetic, propionic, and butyric) id not germinate. He therefore considers these acids toxic; but he used too concentrated solutions. In dilute solutions the * CROCKER has found’ that these seeds germinate readily if the coats are broken or removed. The protoplasm is not dorman 204 BOTANICAL GAZETTE [APRIL fatty acids shorten the after-ripening period of both hawthorn and apple. Mlle. Promsy also used acetic acid with good results on seedlings of tomato and corn. She studied (4'7, 48) the effect of acids on the respiration of germinating seeds of tomato, corn, barley, Dios- corea, and Elaeis guineensis. She finds that organic acids (citric, malic, oxalic, tartaric, and acetic) increase the respiratory quotient and at the same time the intensity of respiration, measured by evolution of CO,. Inorganic acids, on the other hand, do not modify the quotient, except in the single case of the fatty seeds of Elaeis. Seeds were soaked in a solution of the acid for 24-48 hours, then put in germinative conditions in sand, and the sand watered with the solution. Seedlings submitted to the action of organic acids grew more rapidly than the control, increased more in wet weight, and increased more in dry weight, if determined at the end of the germination period when the plants were green. . Seeds treated with inorganic acids, HCl and H.SO,, germinate more quickly than the control. The wet weight of seedlings is increased, dry weight is the same as the control. MartIN FiscHer (12) found that acids greatly increase the absorption of water by colloids, while salts decrease the absorption. He studied the absorption of water by gelatin, fibrin, and frog muscle. A certain degree of acidity seems to be necessary before germi- nation of Crataegus seeds. The acidity of the hypocotyl develops very slowly and little water is absorbed in the early stages of after- ripening. It was thought that absence of free acids might be the limiting factor to growth. An attempt was made to supply this by soaking the seeds in acid before putting them in after-ripening conditions. METHOD OF TREATMENT WITH ACIDS Seeds of Crataegus, with carpels removed but testas intact, were soaked in the acid solution over night at 5° C., washed, and put on moist cotton in Petri dishes. At the end of 14 days they were washed carefully, the coats removed, and the embryos washed in distilled water. They were then tested for presence of free enzymes. In the accompanying table (IV) the results are given 1913] ECKERSON—AFTER-RIPENING 205 in order of the depth of color of the reaction for peroxidase and oxidase. TABLE IV ENZYMES IN HYPOCOTYLS OF CRATAEGUS DUROBRIVENSIS Catalase Peroxidase Oxidase Air-dry at 5° C. 14 days....... Very little Very pale ° a ce ce a Little | Light blue ° Pe OE TIE oe se, Light blue ° ag 00 BERG os x Slightly darker ° mee babyre. ec oe: = Slightly darker ? Wel TO DOIC eee iba a ea x Darker race MOC. 1 x Darker Trace Di YGoe acktic: 2... 2G: x Like after- Dark blue ripen After-ripened go days at 5°C.. = Dark blue Dark blue so sorte snl x Deep blue Darker In 14 days embryos treated with N/rooo acetic acid attain an enzyme reaction equal to that of the untreated embryo after 90 days’ after-ripening. Both N/3400 HCl and N/7o butyric show a great increase in enzymes over the control. The acidity was determined in several cases. The testas and embryos were always carefully washed in boiled distilled water to prevent any trace of external acid vitiating the results. The accom- panying table (V) gives the results of one series. TABLE V ACIDITY IN EMBRYOS OF CRATAEGUS DUROBRIVENSIS Hypocoryts CoryLEDONs IN ACID OVER NIGHT N/20 KOH N/20 KOH Grams |N/20KOH)" Grams N/: ——— ce. per cc. : gram a A OME, iis SI fe sae 0.37 é basic N/7o butyric 16 hours. ... 0.0184 | Neutral| 0.00 | 0.3544 | 0.16 0.45 a SE pean Rang aa! sn, 0.009 0.01 T.1t' | 6.3198 |. 6.05 2.06 ee ene ane 0.0119 | 0.02 1.68 | 0.2420] 0.40 1.65 After seeds have been in N/7o butyric acid 16 hours, the outer cells of the cortex of the hypocotyl give an acid reaction with Dahlia 206 BOTANICAL GAZETTE [APRIL violet. The inner cells are still basic. This shows that the acid had penetrated a little way. The inner cells develop acidity much more rapidly than in the control. Of seeds treated as above with N/7o butyric acid, and after- ripened at 5° C. with testas on, 52 per cent germinated in 53 days; the others decayed. The testas were removed from a lot of seeds after soaking in N/7o butyric acid, and the naked embryos kept on moist cotton at 5° C.; these germinated in 16 days. As shown by the large number of seeds which were killed, N/70 butyric is too strong. More dilute solutions are being used now. N/800 butyric has about the conductivity of N/rooo acetic and N/3400 HCl, which were found to be effective; therefore that is being tested as well as still more dilute solutions. The more dilute solutions are not toxic, instead they greatly increase the rate of the process of after-ripening; therefore, germination is hastened. The after-ripening period of seeds with testas intact was shortened from 80-90 days to 45-53 days; with testas removed, from 30 days to 16-18 days. Summary Condition of the embryo in dry storage-—Food is stored in the _embryo i in the form of fatty oil; there is also considerable lecithin; \ neither starch nor sugar is present. The reaction of the cotyledons is acid, but the hypocotyl is slightly basic. The water-absorbing power of the hypocotyl is less than 25 per cent of the wet weight. There is a series of metabolic changes in the embryo during the _ period of after-ripening. The initial change seems to be an in- creased acidity. Correlated with this is an increased water-holding power, and an increase in the activity of catalase and peroxidase. Near the end of the period of after-ripening there is a sudden increase in the acidity, and in the water content; here oxidase first appears. All of these increase until the hypocotyl is 3-5 cm. long. At this time the fats decrease and sugar appears. Hydro- cyanic acid is present in the cotyledons. The after-ripening period can be greatly shortened by treating the embryos with dilute acids, HCI, butyric, and acetic. The water- holding power, the acidity, and the amount of peroxidase increase much more rapidly, and oxidase appears much earlier, than in untreated embryos. "4 4 ; 1913] ECKERSON—AFTER-RIPENING 297. lt is evident that there is a correlation between acidity of the hypocotyl of Crataegus, its water-absorbing power, production of enzymes, and germinating power. Whether the acidity is causal or merely correlative is not known. There is some evidence, how- ever, that it is causal. GREEN (17, 18) has shown that it leads to the liberation of enzymes; and MartTIN FIscHER (12) that it increases the water-absorbing power of colloids. Other dormant seeds of the Rosaceae are now being studied with the hope of gaining further knowledge on this point. Acknowledgments are due Dr. WILLIAM CROCKER, under whose direction the work was done. UNIVERSITY oF CHICAGO LITERATURE CITED I. APPLEMAN, CHARLES O., Physiological behavior of enzyme and carbo- hydrate transformations in after-ripening of the potato tuber. Bor. GAZ. 52:306-315. 1911. - Bos, H., Wirkung galvanischer Stréme auf Pflanzen in der Ruheperiode. Biol. Centralbl. 27:673-681, 705-716. 1907. 4s. CHRISTENSEN, P., Chemical researches of bulbs in the later phases of the resting period. Bull. Acad. Roy. Danemark (Copenhague). pp. 44. 1908. x 4. CROCKER, eS Réle of seed coats in delayed germination. Bor. GAZ. 42: 265-201. 5- ———, Longevity of seeds. Bor. Gaz. 47:69-72. 1900. “16. Davis, Witmer E., and Rose, R. CaTtin, The effect of external conditions Prats the siteceestag of the seeds of Crataegus mollis. Bot. Gaz. 54: Igt2. : oo NT; a chemiques sur la germination. Centralbl. Bakt. 24?:130-147. 8. Enzyklopidie der rilkermkopinchen Technik. II. Vitale Firbung. pp. 589- 602. 1910 9. Faurt-Fremtet, E. , Les mitochondries des Protozaires et cellules sexuelles. Arch. Anat. Mic. 11: 457-648. Igt0. 10. Fawcet, H. S., Viability of weed seeds under different conditions of treatment and study of their dormant periods. Proc. Iowa Acad. N ~~ 1908. II. Fischer, ALFRED, Wasserstoff- und Hydroxylionen als Keimungsreize. Ber. Deutsch. Bot. Gesell. 25: 108-122. 1907. 12. FIscHER, Martin, Edema; a study of the physiology and the pathology of water absorption by the he organism. New bag IgIo. 298 BOTANICAL GAZETTE [APRIL 13. FRIEDENTHAL, Hans, Methoden zur Bestimmung der Reaktion tierischer und pflanzlicher Fliissigkeiten und Gewebe. ABDERHALDEN’s Handbuc der Biochemischen Arbeitsmethoden. pp. 534-566. 1910 14. GASSNER, Gustav, Uber Keimungsbedingungen einiger siidamerikanischer Gramineensamen. Ber. Deutsch. Bot. Gesell. 28:350—-364. rgro. , Uber Keimungsbedingungen einiger siidamerikanischer Gramineen- samen. Ber. Deutsch. Bot. Gesell. 28: 504-512. 1910. , Vorlaufige Mitteilung neuerer Ergebnisse meiner Keimungsunter- suchungen mit Chloris ciliata. Ber. Deutsch. Bot. Gesell. 29:708-722. IgI2. 17. GREEN, J. REYNOLDS, as ne germination of the castor-oil plant. Proc. Roy. Soc. 48: 370-392. , and JACKSON, H. Sih observations on the germination of the adorei plant. Proc. Roy, sm 77: 69-85. 1905. 19. GUIGNARD, L., Sur la met des glucosides cyanhydriques pendant la permitatiol: Compt. Rend. Sci. Patis 14731023. 1908. 20. HEINRICHER, E., Keimung von Phacelia tdi und das Licht. Bot. Zeit. 67: 45-66. 1909. 21. HempeEt, J., Researches into the effect of etherization on plant metabolism. Kgl. Danske. Vidensk. Selsk. Skrift VII. 6:215-277. 1911. 22. Howarp, W. L., An experimental study of the rest period in plants. The winter rest; initial report on the treatment of dormant woody plants for forcing them into growth. Research Bull. 1. Agric. Exp. Sta. Univ. Missouri. 1910. 23. [RAKLIONOW, P. P., Uber den Einfluss des Warmbads auf die Atmung und Keimung der ruhenden Pflanzen. Jahrb. Wiss. Bot. 51:515-539. 1912 24. Ivanow, Serctus, Uber Oelsynthese unter Vermittlung der pflanzlichen Lipase. Ber. Deutsch. Bot. Gesell. 29: 595-602. 1911. 2m. , Uber . cores des Oels in der Pflanze. Jahrb. Wiss. Bot. 502375 —386. 1 15. 16. 18. ; icin ‘Stoffwechsel beim Reifen dlhaltiger Samen mit besonderer "Berclaeigng der Olbildungsprozesse. Beih. Bot. Centralbl. 28: I5Q-IQI. 1912 ~\27. JesEnKo, F., Einige neue Verfahren der Ruheperiode die Holzgewachse abzukurzen. Ber. Deutsch. Bot. Gessell. 29:273-283. 1011. , Uber das Austreiben im Sommer entblitterter Baume und Straucher. Ber. Deutsch. Bot. a oan 1912. 29. Jost, L., Plant physiology. Eng. t = 30. JOHANNSEN, W., Das Ather Veifeheen, ‘ain Fanticiien 2. Aufl. Jena. 1906 . Kiessiinc, L., Experiments on the germ-ripening of grain. Landw. sak Bayern. 6:449~-514. I9g11 32. Kinzet, W., Uber die Rehan Delbiddior und reifer Samen der Gattung Cuscuta. Landw. Vers. Stat. 54:125-134. 1900. X28, ee ee ae ee ee 1913] ECKERSON—AFTER-RIPENING 299 33- Kress, G., Wilkiirliche Entwicklungsinderungen bei Pflanzen. 1903. : Ube er die Rhytmik in der Entwicklung der Pflanzen. Sitzr. Heidelb. Akad. Wissh. 23: rort. 35. Laxon, Georc, I. Der Keimverzug bei den Koniferen- und hartschali- gen Leguminosensamen. Naturwiss. Zeitschr. ole ne und Landw. 9g: 226-237. IQII. , II. Zur Anatomie und onium eae der Eschensamen. Ibid. 9: 285-298. 1911. ™ 37. , Die Beeinflussung der Winterruhe der Holzgewiichse durch die Nahrsalze. Zeitschr. Bot. 4:561-582. 1912. 38. Mancuam, S., On the detection of maltose in the tissue of certain Angio- sperms. Mew Phyt. 10: 160-166. rog1t. 39. Miter, E. C., A physiological study of the germination of Helianthus annuus. Ann. Botany 24:693-726. IgIo. 40. Mottscu, H., Uber ein einfaches Verfahren Pflanzen zu treiben (Warm- badmethode). Sitz. Kais. Akad. Wiss. 11'7:87-117. 1 I. , Uber das Treiben von Pflanzen mittelst Radium. Sitz. Ber. Akad. Wien 121:121-139. 1912. Vv 42. MULLER-Tuurcau, H., und ScHNEER-ORELLI, Beitrige zur Kenntniss der Lebensvorgiinge in ruhender Pflanzen. 1. Uber den Einfluss ie Vor- erwarmens und einiger anderer Faktoren. Flora 101: 309-372. ¥ 43. ——_—, Beitriige sur ie ni Lebensvorgiinge in ruhenden pera teilen. Flora 104:386-446. 1 44. Nose, F., Handbuch der Semeauds 1876. 45. NoBBE aad Hantet, Uber die Resistenz von Samen — die déusseren Factoren der Keimung. Landw. Versuchs. Stat. 20:63 1877. 46. Pammet, L. H., and Kinc, Cuarzotre M., Delayed gominalion. Proc. Towa Acad. 1'7: 20-33. 1910 47. Promsy, G., De l’influence de l’acidité sur la germination. Compt. Rend. Acad. Sci. Paris 152:450-452. IgII. , De l’influence des acides organiques et du glucose sur la respiration des graines en voie de gonflement. Rev, Gén. Botanique 23:313-318. IQI2. » Ravenna, C., and Veccut, C., Hydrocyanic acid formation in germination of seeds. Atti R. Accad. Lincei V. 2:491-495. I9II - Scumipt, R. H., Uber Aufnahme und Vosgsheltina % von fetten Oelenpflan- zen. Flora 74:300-370. 1891. WALLERSTEIN, M., Die Verinderungen des Fettes wihrend der Keimung und deren Bedeutung fiir die rier nape Ben Vorgiinge der 4 Keimung. Abst. Chem. Centralbl. 1:63. 1 52. WiesNeER, J., Biologie der Pflanzen. II. Aufl. pp. 5 1902. & 53. Weer, F., Uber die Abl g der Ruheperiode der Hokeewiches durch Verletzung der Knospen beziehungsweise Injektion derselbe mit Wasser. nz. Kais. Akad. Wien 10:182-183. 1911. $ un ° ut La . THE CALIFORNIA PAROSELAS S. B. PARISH (WITH FIVE FIGURES) This paper is based on a study of the ample collections in the herbarium of the University of California, and of the material in the private herbaria of Dr. A. DAavipson and of the writer. While the numerous extralimital material in these collections has been carefully studied, the citation of specimens is confined, for the most part, to those collected within the boundaries of the state. Dr. HAL not only placed the collections of the University at the writer’s disposal, but allowed him the use of a preliminary study which he had prepared, and most generously aided him in other ways. For the drawings, from which the figures have been repro- duced, the writer is under obligations to the skillful pen of Mrs. CHARLOTTE M. WILDER. The generic name The genus Dalea was founded by Linnaeus in 1737, in his Hortus Cliffortianus, but in the Species Plantarum of 1753 he reduced it to Psoralea. The latter year being now accepted as the initial date for phanerogamic nomenclature, we are debarred from going back to LINNAEUvs’ earlier use of the name. It was revived by JussIzv in 1789, and according to present rules that must be taken as the authoritative date for the name, and it is with this citation that it is maintained in the new Gray’s Manual.t Unfortunately, in the interval it had been used for two other genera. In 1756 P. Brown applied it to what is now universally regarded as Eupato- rium, so that, as a synonym, his use may be disregarded. But GAERTNER, in 1788, gave it to what ENGLER and Prantt and the Kew Index now call Microdon Choisy (1823). This scrophulariace- ous genus, therefore, has the prior title by a single year, and the leguminous genus must take the later name Parosela Cav. (1802). tIn the Natiirlichen Pflanzenfamilien, Dalea Linn, is retained. Botanical Gazette, vol. 55] [300 1913] : PARISH—CALIFORNIA PAROSELAS 301 This needless and confusing change should have been provided against in the list of nomina conservanda, and it is to be hoped that the oversight may be remedied in a future revision. Distribution Mexico is the center of distribution of the genus, fully 120 species (119, Conzatt1) having been described from the temperate regions of that republic. Thence it extends along the Andes to Chile, where it has. its southernmost representative in Dalea multifoliata, at 30° south latitude. Crossing the United States’ boundary, it is well developed in the Lower Sonoran life-area; 17 species are found in Texas (CouLTER), 19 in New Mexico (Hammonp), and 33 in Arizona (THORNBER). The most northern species is Parosela alopecuroides, which reaches southeastern North Dakota, at latitude 30° N., and the same species extends east to Tennessee (GATTINGER). Besides the continental species, two outlying ones are found on the Galapagos Islands. In California it is a char- acteristic genus of the deserts, a single species passing into an arid border of the cismontane region. | Parosela PaROSELA Cav. Descr. 185. 1802.—Dalea Juss., Gen. 355. 1789; Asagraea Baillon, Adansonia 9:232. 1870.—Annual or perennial herbs, shrubs, or trees, more or less glandular-dotted. Leaves odd-pinnate, rarely simple, with minute subulate stipules. Flowers in spikes or simple racemes, rarely scattered or solitary; bracts caducous, in ours subulate and inconspicuous; calyx 5-toothed; petals all with claws, that of the usually cordate banner inserted at the bottom of the calyx, and those of the wings and keel adnate below the middle of the cleft stamineal sheath; stamens 10, rarely 9, monadelphous; anthers uniform; ovules 2, rarely 4-6; pod membranaceous or chartaceous, indehiscent, 1-seeded. ARTIFICIAL KEY TO THE CALIFORNIAN SPECIES Perennial herbs. Calyx long-villous, its teeth filiform. ........ ‘2. mollis. Calyx silky-canescent, its teeth ovate-acute. .2. P. Parryt. 302 BOTANICAL GAZETTE _ [APRIL Woody shrubs. Flowers in condensed headlike spikes. Stems ooponnd yet WOR te Fe 10 ks ess . P. polyadenia. eae sparsely Sete stasiivtar: ates ee A oe Si is 04 ee eo . P. Emoryi. F aa in loose spikes or racemes. Leaves pinnate, or a few simple. Leaves and twigs hoary-tomentose...... 5. P. neglecta. Leaves and twigs appressed silky-pubescent. Ree ree CS e ss s 62P iS ohnsonii. Leaflets decurrent or confluent........ 7. P. californica. Leaves mostly simple, but a few 3-pinnate..7a. P. californica simplifolia. Léaves all simple, glabrate .............. Ee is Spinose tree, hoary-pubescent, nearly leafless ...9. P. spinosa. SYNOPSIS OF THE SPECIES ee *Ovules 2; pod included | Flowers spicate; herbs 1. PAROSELA MOLLIS (Benth.) Heller, Cat. N. Am. PI. ed. 2. 6. 1900.—Dalea mollis Benth. Pl. Hartw. 306. 1848.—Herbaceous from a perpendicular root, the spreading stems 5-15 cm. long, dotted with small, flat, brown glands, soft-villous, as are the leaves: leaflets 9-13, oblong, cuneate-oblong, obovate, or obcordate, usually retuse, 3-8 mm. long, dotted with a row of small marginal glands: flowers numerous in oblong spikes, 1-6 cm. long; calyx 6 mm. long, its teeth filiform from a triangular base, equaling or exceeding the glandular-dotted tube; corolla rose-tinted, not exceeding the calyx teeth; banner 2 mm., wings and keel 3 mm. long, the latter mostly with a small gland at base: pod obovate, hirsute, and glandless, 3 mm. long: seed brown, reniform, 2 mm. long.—Fig. 1. Probably a short-lived perennial, sometimes flowering the first year. The flowers are on very short pedicels, bracteolate at base by a pair of swollen pointed glands, which persist on the rachis after the fall of the fruiting calyces. Type.—‘In vicinibus Monterey”; certainly an error. According to Warson, in the Botany of California, it was first collected by CouLTER, prob- ably in southern Arizona. DISTRIBUTION.—A common species in sandy and gravelly soils through- out the Lower Sonoran of the Colorado and Mojave deserts; thence northeast to southern Nevada (GooppING 2237), southeast through Arizona (THORNBER) oT ae as tee eee eee 1913] _PARISH—CALIFORNIA PAROSELAS 303 and New Mexico to Coahuila, Mexico (PurpuUs 115), south to Guaymas (PALMER) and Lower California (BRANDEGEE). PECIMENS EXAMINED.—Mojave Desert: Inyo Mountains, S. W. AusTIN 441; Panamint Cafion, May 14, 1906, HALL 6999; Bagdad, May 2, 1892, BRANDEGEE; Camp Cady, May 1882, ParisH 83; Sheephole Mountains, May 1895, HALL 6097. Colorado Desert: Palm Springs, April 10, 1880 ParIsH 88, and April ro, 1893, DAvipson; Coachella, April 1905, GREATA 415, and HALL 5792; Mecca, April 1904, Mrs. M. McKippen; McCoy Wash, April 1905, HALL 5932; Borregos Spring, April 28, 1894, BRANDEGEE; Hodges Mountain, April 1905, HALL 5975; Salton, April 12, 1892, Davy 8049; Chucka- walla Bench, December 3, 1904, E. E. SCHELLENGER 99; Palo Verde, April 1905, HALL 5956; Calexico, March 29, 1902, Davy 8005; Dixyland, October 18, 1912, PARISH 8312. ~ Fic. 1.—Parosela mollis: a, leaf; b, part of rachis, showing the glandular brac- teoles; c, calyx, from the inside, to show the glands, which are concealed on the exterior by the dense hairs; d, seed; e, mature pod; a,c, d,e, X3- 2. PARosELA Parry (T. & G.) Heller, Cat. N. Am. Pl. ed. 2. 6. 1900.—Dalea Parryi T. & G., Proc. Am. Acad. '7:397. 1868.— Perennial, the slender woody stems ascending, 1-6 dm. tall, finely and closely puberulent, or glabrate, dotted with small flat, dark glands: leaflets 3-21, oblong to obovate, obtuse or retuse, I-3 mm. long, sparsely puberulent or glabrate, obscurely glandular-dotted or glandless: flowers numerous in pedunculate spikes 5-8 cm. long; calyx 3 mm. long, nervose, silky-canescent, obscuring the rows of small glands in the intervals, or glabrate; upper teeth triangular 304 BOTANICAL GAZETTE [APRIL or ovate-acute, the lowest narrower and longer, about half the _ length of the tube; corolla minutely glandular-dotted, twice exceed- ing the calyx; banner broadly orbicular, 1.5-2 mm. high and as Fic. 2.—Parosela Parryi: a, branch, natural size; b, calyx; ¢, petals; d, pod; all X 2.5. wide or wider; wings 2 mm. and keel 4 mm. long, the lower half of the banner and the upper half of the keel blue, the remainder white: pod gibbous, glandular, 2 mm. long: seed reniform.—Fig. 2. 1913] PARISH—CALIFORNIA PAROSELAS 305 TypE.—“ Gravelly hills near Ft. Mohave, Dr. J. G. Cooper, and lower down on the Colorado, near tl uth of the Williams River, Dr. C. C. Parry.” DISTRIBUTION.—Lower Sonoran of the Colorado Desert, thence to Arizona (PurPus 8507) and adjacent Mexico (PALMER) and Lower California (BRANDE- GEE). SPECIMENS EXAMINED.—Thermal, May 1903, DAvimson; Mammoth Tank, March 17, 1882, PARISH 1180; Cafion Springs Wash, February 25, 1904, SCHELLENGER 63; Cane Spring, April 1905, Hatt 5846; Chuckawalla Bench, December 1906, SCHELLENGER 95; Palo Verde, April 1905, HALt 5975; Virginia Dale, May 1905, HALL 6041. Parosela Orcuttii, comb. nov.—Dalea Orcuttii Wats., Proc. Am. Acad. 20:359. 1885, a species of adjacent Lower California, may be looked for near the boundary. It resembles P. Parryi, but the stems are not glandular- dotted, and the corolla is but little longer than the calyx teeth. Tt Flowers in condensed spikes which are sessile at the ends of branch- lets, the rachises deciduous, leaving the branchlets as a subspinose armament; calyx teeth similar, or nearly so. Shrubs, even the old wood glandular 3. PAROSELA POLYADENIA (Torr.) Heller, Cat. N. Am. PI. ed. 2. 6. 1900.—Dalea polyadenia Torr. ex Wats., Geol. Expl. goth Par. 5:64. pl. 9. 1871.—Shrub 5-10 dm. tall, sparsely spinose, the short and stout divaricate branches canescent with a dense pannose tomentum, and copiously dotted with large yellow or red guttate glands: leaves on short petioles, 1-2 cm. long; leaflets 5-II, ovate, 1-5 mm. long, tomentose and sparsely glandular; flowers numerous; spikes globose or oblong; calyx villous and glandular-dotted, 3.5-4 mm. Jong; teeth subulate from a broad base, nearly as long as the tube; petals rose-pink or purple, each usually with a small gland at the apex, rarely somewhat bearded, 3.5 mm. long, little exceeding the calyx teeth: pod 3-5 mm. long, pubescent above. Type.— Borders of the Truckee Desert, Nevada.” DistTRIBUTION.—Inyo County, thence into Nevada (Wadsworth, KENNEDY, Candelaria, SHocKLEY 275). PECIMENS EXAMINED.—Owens Valley, PURPUS 1960. PAROSELA POLYADENIA (Torr.) var. subnuda, comb. nov.— Dalea polyadenia Torr. var. subnuda Wats., Bot. Cal. 23441. 1880. —Glabrous or nearly so; calyx glabrous and glandular-dotted, the teeth villous-ciliate. - 306 ° BOTANICAL GAZETTE [APRIL Type.—‘Owens Valley (Dr. W. MATTHEWS); Southern Utah (W. Joun- SON).” SPECIMENS EXAMINED.—Mono County, July 1888, Mrs. J. H. HARcouRT; Owens Valley, S. W. Austin 171; Owenyo, June 1911, DAvipson. 4. PAROSELA Emorvt (Gray) Heller, Cat. N. Am. Pl. ed. 2. 6. 1900.—Dalea Emoryi Gray, Mem. Am. Acad. II. 5:315. 1855; Torr. Pac. R.R. Rep. 5:360. pl. 2.—Shrub 1-2 m. high, destitute of true spines, the numerous slender intricate branches hoary pubes- cent and sprinkled with small brown or red prickle-shaped glands: leaves 1-9 cm. long, pubescent and sparsely glandular; leaflets 3-13, the terminal one usually narrower and longer than the lateral, rarely a few of the uppermost simple: flowers 10-20; spike globose, I—2 cm. in diameter; calyx silky villous, 6 mm. long, colored orange by the abundant minute subulate glands; teeth linear, as long as the tube; corolla bright purple, little exceeding the calyx teeth; petals nearly equal, about 4 mm. long: pod 3 mm. long, dotted with red glands. Typr.—‘On the desert tablelands of the Gila, 1852.” DisTRIBUTION.—Lower Sonoran of the Colorado Desert, thence into adjacent Arizona, and throughout Lower California to La Paz (BRANDEGEE SPECIMENS EXAMINED.—Palm Springs, April 1882, April 18, 1896, April 23, 1907, PARISH 93, 412, 6106; April 10, 1893, DAVIDSON; 1902, F. GILMAN; May 1894, L. D. Copetanp; April 20, 1906, GRANT; May 22, 1911, O. F. SELLIG; July 25-August 14, SCHELLENGER; Indio, May 8, 1903, JONES; McCoy Wash, April 1905, HALL 5946; Borregos Spring, April 19, 1906, JONES; abundant toward the foothills, Mecca, June 28, 1912, PARISH 8133; Old Beach, near Holtville, both above and below sea-level, June 30, 1912, PARISH 8088. ** Ovules 2, collateral; pod glandular-dotted, exseried; the dead rachises persisting as a spinelike armament. Shrubs, the mature wood glabrous and glandless | Flowers sessile, or nearly so, in open spikes; calyx teeth dissimilar, the lower one narrower and mostly longer than the upper pair; leaves pinnate, or a few of the uppermost simple 5. Parosela neglecta, n. sp.—Dalea arborescens Parish, Zoe 42341. 1894, non TORREY.—Frutex subspinescens, 1-1.5 m. altus, caulibus junioribus tomentosis, cum glandulis parvis subulatis instructis; foliolis 3-7 oblongis vel obovatis sub tomento canes- cente obscure glandulosis; spicis 7—15-floris; calyce villoso minute glandulosoque, 8-9 mm. longo, tubo valde nervoso dentes aequante, 1913] PARISH—CALIFORNIA PAROSELAS 307 dentibus superioribus duobus acuminatis vel lanceolatis; corolla - caerulea, vexillo oblongo-cordato, 8 mm. longo, 4 mm. lato; alis carinaque 6-7 mm. longis; ovario glanduloso-punctato.—Fig. 3. _ Inrecent years this plant has been taken for Dalea arborescens Torr., and iN Some respects it agrees with the character of that species given in Plantae Thurberianae, but is excluded by the phrases “floribus in spicam densam brevem 308, BOTANICAL GAZETTE [APRIL congestis . . . . spikes ovate or oblong,” with which it does not in the least accord. DistRIBUTION.—So far as known, local in the neighborhood of Barstow, in the Mojave Desert. Fishpond PR (Daggett), May 1882, PARISH 644, type; Barstow, May 14, 1897, F. W. Hussy 141; May 3, 1906, HALL and CHANDLER 6831; May 18, 1905, HALL ee 6. PAROSELA JOHNSONIE Vail, Bull. Torr. Bot. Club 24:17. 1897.—Dalea Johnsonii Wats., Geol. Expl. 40th Par. 5:64, 1871.— Shrub 1-1.5 m. high, the slender branches scantily appressed- pubescent or glabrate, glandless or nearly so: leaflets 5-7, linear to narrowly oblong, thinly pubescent and obscurely glandular, narrowed to the rachis: flowers short-pedicellate; calyx sparsely pubescent and nearly glandless, obscurely nerved, 5-5.5 mm. long, the teeth less than half the length of the tube, the upper pair triangular-acute; corolla deep purple; petals-about 6 mm. long. Type. ‘Near St. George, on the Virgin River, Utah.” — DIstTRIBUTION.—From southern Utah to the borders of Arizona (Grand Cafion, Witson) and the eastern border of the Colorado Desert SPECIMENS EXAMINED.—Eastern edge of the Colorado Desert, SCHEI- LENGER; Kane Spring, Ord Mountain, May 1, 1906, Hatt and CHANDLER 6826; Cottonwood Mountains, May 11, 1905, HALL 6024. PAROSELA JOHNSONII (Wats.) Vail var. Saundersii, comb. nov. —P. Saundersii Abrams, Bull. N.Y. Bot. Gard. 6:396. 1910; P. Wheeleri Heller, Muhlenb. 2:216. 1906; Dalea Saundersit Parish, Bull. S. Cal. Acad. 2:83. pl. 2. 1903.—Leaflets 5~9, lanceo- late, sessile, or on short petiolules, glabrate; stems sparsely prickle- glandular. Victorville, May 12-14, 1903, C. F. SAUNDERS, and May 1905, HALL 6197; Big Pine, Inyo County, May 29, 1906, HALL and CHANDLER 7222; Owens Valley, May 11, 1906, HELLER 8236. PAROSELA JOHNSONII (Wats.) Vail var. pubescens, n. var.— Calycis dentibus majoribus tenuioribusque; legumine pubescente simul glanduloso. Lee’s Ferry, Arizona, June 13, 1890, JONES 3076. PAROSELA JOHNSONI (Wats.) Vail var. minutifolia, n. var.— Foliolis 5-7, oblongis, 2-4 mm. longis. Mouth Panamint Cafion, May 11, 1906, Hatt and CHANDLER 7002; Providence Mountains, May 24, 1905, BRANDEGEE. 1913] PARISH—CALIFORNIA PAROSELAS 309 7. PAROSELA CALIFORNICA Vail, Bull. Torr. Bot. Club 24:17. 1897.—Dalea californica Wats., Proc. Am. Acad. 112132. 1876.— Shrub 1-2 m. high, hoary with a fine upwardly appressed pubes- cence, and sparsely beset with prickle-shaped glands: leaves 2-3 cm. long; leaflets 3-7, the terminal often longer than the others, rarely a few simple, the edges thickened, hoary-pubescent, con- cealing the small glands, decurrent on the rachis or confluent; calyx 5 mm. long, nerved, minutely glandular-dotted, thinly pubescent, in fruit glabrate; teeth shorter than the tube, the upper pair ovate-acute; corolla bright purple; petals 8-8.5 mm. long; pod 8 mm. long; seed castaneous, ovate.—Fig. 4. Extreme forms, such as Jones’s Palm Spring specimen (Hb. U. Cal. 12852), having leaves 3-foliolulate to simple, connect this species too closely with Dalea Fremontii Wats., and it is not impossible that it must be reduced to a variety thereof. YPE.—‘‘ Known as yet’ only from scanty specimens recently collected by Dr. Pind in the San Bernardino Mountains, California.” According to statements made to the writer by Dr. PARRy, the type was collected east of Banning, on the borders of the Colorado Desert. DIsTRIBUTION.—Western borders of the Colorado Desert, at 150-600 m altitude, and in the eastern part of the San Jacinto Valley, in the cismontane area. SPECIMENS EXAMINED.—Near Banning, 1882, PARISH 644, and May 1892, Davipson; Palm Springs, April 1896, PARISH 4111, May 10, 1903, JONES, 1904, R. J. Smit 308, May 21, rorz, O. F. Setiic, and May 1902, HALL 1832; Cottonwood Mountains, May 1905, HALL 6025; between Palm Springs and Whitewater, July 25-August 14, E. E. SCHELLENGER, intermediate between the species and the following variety. PAROSELA CALIFORNICA (Wats.) Vail var. simplifolia, n. var.— Glaberrima, ramis eglandulosis: foliis simplicis, rariusve pinnato- 3-foliolatis; calycis majoribus. Western part of the Colorado Desert, 1904, M. F. Girman 51 (in Herb. Univ. Cal.). Tt Flowers pedicellate, in simple racemes; leaves all simple 8. PaRoseLta Scuorti (Torr.) Heller, Cat. N. Am. Pl. ed. 2. 6. 1900.—Dalea Schottii Torr. Bot. Mex. Bound. 53. 1859.—Com- pact spinose shrub 1-3 m. high, with numerous slender, green and glabrate, glandless branches: leaves linear, 3-25 mm. long, puberu- lent, but soon glabrate, bearing near the thickened margins a 310 BOTANICAL GAZETTE : [APRIL few small, dark, impressed glands: racemes 4-8 cm. long, 6-20- flowered; pedicels 1-1.5 mm. long; calyx 5 mm. long, sparsely hirsute, glabrate in fruit, nerved, and with a row of small red glands, Fic. 4.—Parosela californica: a, flowering branch, natural size; b, c, d, leaves; ¢, calyx and stamens; /, calyx laid open; g, petals; all X2.5. 1913] PARISH—CALIFORNIA PAROSELAS 3II -very obscure in flower, but distinct in fruit; teeth ciliate, the upper pair a little wider and more obtuse; corolla deep purple; banner 8 mm., wings 10 mm. and keel 8-10 mm. long: pod 1 cm. long, its glands, red: seed castaneous, obovate, 7-8 mm. long.—Fig. 5. | IS ae : — = Ze \ Fic. 5.—Parosela Schottii: a, flowering branch, natural size; 6, calyx; ¢, petals; a, pod and fruiting calyx; all X3. 312 BOTANICAL GAZETTE [ PRIL Some of the lowest flowers are often in the axils of leaves. The fra- grance of the abundant bloom is sometimes diffused for miles on the quiet desert air. Type.—‘ Diluvial banks of the Colorado, February, Scuorr.”’ DistripuTion.—An abundant species of the Colorado Desert, extending into adjacent Arizona and into Lower California (BRANDEGEE). PECIMENS EXAMINED.—Palm Springs, April 10, 1880, April 1896, PARISH 83, 4113, April 1904, L. D. CopELanp 4, October 15, 1904, SCHELLENGER 3, 1902, M. F. GILMAN 21, April 1905, HALL 5738, and May 21, 1011, O. F. SELLIG; Coachella, April 1905, GREATA and Hatt 5781; Chuckawalla Mountains, April 1905, HALL 5973; Indio, April 1905, HALL sqggo. PAROSELA ScHotTti (Torr.) Heller var. puberula, n. var.— Rami juvenes foliaque canescente puberuli; calyce parum vel dense pubescente. Colorado Desert, April 1905, BRANDEGEE; Borregos Spring, April 29, 1904, BRANDEGEE; Cajon de Santa Maria, Lower California, May 10, 1889, BRANDE- GEE. *** Ouules 4 (—6); calyx teeth similar, pod glandular-dotted, exserted; flowers spicately scattered on stout spine-tipped branchlets (Asagraea Baillon, Adansonia 9:232. 1870 g. PAROSELA SPINOSA Heller, Cat. N. Am. Pl. ed. 2. 7. 1900.— Dalea spinosa Gray, Mem. Am. Acad. 5:315. 1855; Torrey, Pac. R.R. Rep. 73:9. pl. 3. 1856; Asagraea spinosa Baillon, Adansonia 9:233. 1870.—Intricately branched tree 4-7 m. high, the numer- ous spinescent branchlets hoary with a fine close pubescence, and sparsely dotted with small flat glands; leaves very few and promptly deciduous, narrowly oblong, the margins thickened, 5 mm. long: flowers on pedicels 1 mm. long; calyx 5 mm. long, strongly nerved, encircled above with a ring of large, reddish, guttate glands; teeth 2 mm. long, ovate; corolla dark blue; banner 6 mm. long and as broad; keel and wings 8 mm. long; anthers with an oblong red gland at base. The flowers do not extend to the sharp horny spine of the branchlets, not all of which are floriferous, and which cannot be regarded as the peduncles of a true spicate inflorescence. Parosela Kingii (Wats.) has solitary flowers borne on like spinescent branchlets, and Holécantha Emoryi Gray has an analogous inflorescence. Type.—‘‘Arroyos on the Gila; and on the California Desert west of the Colorado.” 1913] PARISH—CALIFORNIA PAROSELAS 313 DiIsTRIBUTION.—At low altitudes in ef Colorado Desert, thence to adjacent Arizona, Sonora, and Lower Cali SP NS EXAMINED.—Colorado bea "soe A. W. ANTHONY; White- water, May 1904, R. G. SmitH; Palm Springs, June 1895, DAvipson, in full flower, and April 1907, PARIsH; Chuckawalla Bench, June 25, August 14, 1903, SCHELLENGER 2, 3; Indio, June 1880, PARISH 22; toward the foothills near Mecca, and in Red Cafion, abundant and in full bloom, June 28, 1912, PARISH 8108. SPECIES INCERTA DALEA ARBORESCENS Torr. ex Gray, Mem. Am. Acad. II. 5:316. 1885.—‘‘Much branched, almost glandless, subspines- cent; the adult branches glabrate, the younger, together with the leaves and the calyces, canescent-tomentose: leaflets 5, approxi- mate, obovate: flowers congested in a short dense spike; bracts small, subulate; the acuminate teeth of the calyx as long as the campanulate tube, the two upper oblong-triangular, the others narrowly lanceolate: petals (purple?) about equal. “*A small tree!’ Glands scarcely any, a few minute tubercular ones occasionally found on the branchlets when denuded of their dense woolly cover- ing. Leaves petioled, the leaflets only 2-3 lines long. Flowers 5-6 lines long; the calyx large in proportion, the tube obscurely striate. Vexillum obcordate.” The above is the original character, the first paragraph translated. The type is said to be from the “Mountains of San Fernando, a southern branch of the Sierra Nevada, California; April, Fremont.” This region is now well known, but no species of Parosela has been collected there; certainly it could hardly have escaped notice if a tree. The type specimen is a mere fragment, from which little can be learned. The condensed inflorescence indicates that it should be placed near Parosela polyadenia and P. Emoryi, where it was located by Watson in the Botany of California. SAN BERNARDINO, CAL. THE EFFECT OF SOME PUGET SOUND BOG WATERS ON THE ROOT HAIRS OF TRADESCANTIA GEORGE 5, KRIGG The theory advanced in this paper is that plants other than bog xerophytes are excluded from peat bogs because of their inability to produce normal root hairs in the toxic habitat of bogs, their absorptive surface being thus so decreased that they cannot get water enough to enable them to live. The writer has also confirmed with Puget Sound bog waters certain results obtained by other workers with bog waters from the Middle West and extreme East. - Description of bogs The xerophilous character of the flora of peat bogs is well known. In the Puget Sound region the plants most characteristic of undrained bogs are Ledum groenlandicum, Kalmia glauca, Oxycoccus oxycoccus intermedius, Sphagnum, and Drosera rotundi- folia. The first four plants named are found in every undrained bog that the author has visited in the region, while the last one has been found absent from a few. Other plants sometimes found in bogs of the region are Pinus monticola, Betula glandulosa, Salix myritlloides, Myrica Gale, Eriophorum russeolum, and Juncus oregana. Tsuga heterophylla and Pinus contorta are found on the drier hummocks in bogs (8), Ledum columbianum and Myrica californica are reported to be found in the beach bogs along the Pacific Ocean instead of L. groenlandicum and M. Gale (8). Peat bogs are common in the Puget Sound region. The studies reported in this paper are based on six bogs. One of these is situated within the city of Seattle at the corner of E. 55th St. and 6th Ave. N.E. During the last two years the forest surround- ing this bog has been cleared away and the streets along its edges _ have been filled with dirt from the neighboring hills. It has not been drained however and its flora is still just as typical as it was before the surrounding forest was removed, except that Drosera Botanical Gazette, vol. 55] [314 1913] RIGG—EFFECT OF BOG WATERS 315 rotundifolia has disappeared, which was fairly common in this bog in 1908. It is a small bog, about 100 by 200 m. in extent. For convenience it will be referred to as the Seattle bog. The largest bog studied is situated about 1760 m. east of Henry Station on the Seattle-Everett interurban railway. The undrained portion of this bog is perhaps 16 hectares in area, and its flora is typical, including Drosera. In addition to the usual bog plants, Pinus monticola is common, and Trientalis arctica is found along the border. The natural contour of the region is such that there is some drainage from the northern end of this bog into a small creek, and that portion of it lacks Drosera and Pinus and has Lysichiton kamtschatcense. This bog will be referred to as the Henry bog, The bog situated about 5280 m. southeast of Fauntleroy Park in Seattle is a little smaller than the Henry bog. Its area is esti- mated at about 10 hectares. Drosera is abundant in it, and Trientalis arctica is common along its margin. This bog will be designated as the Fauntleroy bog. The bog situated at Echo Lake station on the Seattle-Everett interurban railway is slightly smaller even than the Seattle bog. It is on the margin of Echo Lake and its edge forms the bank of the lake for a short distance. The bog flora is typical right up to the open water of the lake; Drosera is abundant, and Comarum palustre is found on the border of the lake immediately adjacent to the bog. This bog will be called the Echo Lake bog. It is about 8800 m. distant from the Henry bog. The bog that will be referred to as the Green Lake bog is situated just north of the city limits of Seattle. It is a little over 1760 m. north of Green Lake, which is entirely within the city limits. There is now remaining only about 0.4 hectare of this bog; formerly it was about 12 hectares in extent, but nearly all of it has been Stripped of its original vegetation and drained. A good deal of it has been divided into small garden tracts and some of these are now under cultivation. The uncleared portion is drained by road- side ditches on two sides; water flows freely from the bog into one of these ditches during the rainy season and there is consider- able seepage into the other one. This bog still has the typical bog 316 BOTANICAL GAZETTE [APRIL plants of the region, including Drosera. In addition to these, however, it contains the following plants not usually found in bogs: Pseudotsuga taxifolia, Picea sitchensis, Thuja plicata, Tsuga hetero- phylla, Alnus oregona, Comarum palustre, Lysichiton kamitschatcense, a Carex, and a small orchid. It will be noted that some of them (e.g., Lysichiton kamtschatcense) are found on the borders of other bogs, and that one of them (Tsuga heterophylia) is found on the dry hummocks in other bogs. Apparently the partial drainage here has allowed the entrance of plants not found in typical bogs, but has not driven out the typical bog plants. The last of the six bogs is situated on Mount Constitution at an elevation of about 666 m.; the mountain itself attains a height of 880m. It is situated on Orcas Island, one of the San Juan group, which lies between the strait of Juan de Fuca and the strait of Georgia. Several peat bogs situated on this mountain have been drained and thus converted into meadows, which have been used for both hay and pasturage. Drainage and clearing seem to have completely destroyed the bog flora and substituted a flora not at all characteristic of peat bogs. The bog water for use in the experiments has been obtained in all cases as follows. Care was first taken to select a spot that was centrally located in the bog and had a typical bog flora. The mass of vegetation and fibrous peat was cut away with a strong knife from an area about one foot square. Then the soft peat was scooped out below this until a cavity was formed that would soon fill with water. The water was dipped up in a wide-mouth glass bottle and poured into glass containers. The depth to which this had to be scooped out varies with the season; in winter about 35 cm. sufficed in most of the bogs; in late summer it was necessary to dig 90 cm. In the case of the water obtained from the Henry bog on October 10, 1911, it was found that it would not accumulate in half an hour by digging even 90 cm. deep, and a glass jar was filled with very wet peat and the water was squeezed through cheesecloth in the laboratory. The tap water used was that supplied to the laboratories from a wooden supply tank on the University campus. It is pumped into this tank from Lake Washington. 1913] RIGG—EFFECT OF BOG WATERS 317 The expression “normal root hairs” used in this paper with reference to Tradescantia (the species common in greenhouses, and known as wandering Jew) means such root hairs as grow on the roots of cuttings in tap water. These hairs cover the entire surface of the root even when it reaches a length of 7o mm. or more. They are almost uniformly distributed, 4 mm. or more in length, mostly straight, and appear to the naked eye like somewhat silky fibers. _ Over 200 specimens of this plant grown in tap water have been examined and there has been found practically no variation from _ this description. Investigation In October 1909 experiments were begun on the germination of wheat, corn, beans, and peas in moist peat and between sheets of moistened blotting paper. It was found that these seeds germi- nated just as readily when the moisture was furnished by bog water as when it was furnished by tap water. In the fall of 1910 Ledum groenlandicum and Kalmia glauca were propagated by cuttings in both bog water and tap water in the laboratory. Young roots from both of these species from both inds of water were examined and found to be entirely devoid of root hairs. Some of the roots examined were produced on old roots formed before the plants were removed from the bog and some were produced on stems. TRANSEAU (10) found root hairs absent in Oxycoccus macro- carpus. He also found that the roots of Larix laricina were “composed of mycorhiza,’ and that their cortical tissues were early destroyed by a fungus. When he grew these plants in a well- aerated culture solution ‘‘normal roots with root hairs were pro- duced.” Covitte (1) found Vaccinium corymbosum to be devoid of root hairs. He found also that the walls of the epidermal cells of the roots were 1.3-2.5 thick, this being four to six times as thick as the walls of epidermal cells of wheat roots. He computes that a given section of wheat root presents about ten times as much absorptive surface as a section of blueberry (Vaccinium corym- bosum) root of the same area. 318 BOTANICAL GAZETTE [APRIL In the fall of 1909 and again in 1910-1911 experiments were conducted on the effect of bog water on the production of root hairs on cuttings of Tradescantia. The experiments reported in the following table were carried out in 1910-1911 in 150 cc. glass bottles with extra wide mouths. TABLE I THE PRODUCTION OF ROOT HAIRS ON TRADESCANTIA IN BOG WATER RoOoT HAIRS No. or bata Slightly Much U! Normal stunted stunted None PRE DO ee. 16 a 3 9 4 ICY DON PGs 10 ce t 9 Pa wecmtieroy bow... <........- 10 ~ 3 6 I Cae eS ro, 5 oe i 2 3 Green Lake bog. oie. ik. 10 10 oF Hs Mount Constitution bog...... 3 a 3 It will be noted that the Green Lake bog is the only one whose water allowed the production of root hairs that were normal as to length and abundance. It seems evident that this lack of toxic effect is a result of drainage. Of the 44 plants grown in water from undrained bogs, 8 plants (18 per cent) produced no root hairs, while 29 plants (66 per cent) produced root hairs that were much stunted, and 7 plants (16 per cent) produced root hairs that were slightly stunted. The above table is based on the roots produced within the first 14 days; these roots were invariably shorter than those produced in tap water within the same time. The new roots that started after that time approximated the length of the roots of plants grown in tap water and produced root hairs that were longer and much more abundant, in many cases approximating normal. The tops of the bottles in which these experiments were carried on were not closed, the surface of the water being exposed freely to the air. DAcHNowsKI (2) found that aeration reduced the toxic effect of bog water from Cranberry Island (Ohio). In addition to the tests made on bog water and tap water the following tests have been made on other waters of the region: Echo 1913] RIGG—EFFECT OF BOG WATERS 319 Lake (5 plants), bog spring on Mount Constitution (3 plants), Mud Lake (10 plants), well water at Friday Harbor, Washington (25 plants). In every one of these cases the root hairs were normal. The water from Echo Lake was dipped up by the writer while standing on the edge of the Echo Lake bog; it was obtained at a distance of 15 feet from where the water from the Echo Lake bog was obtained. The bog spring on Mount Constitution referred to emerges from the side of the mountain and its water seeps into the swamp which gradually merges into the bog. It has the coffee color characteristic of bog water, but not to so marked a degree as the water obtained from underneath typical bog vegetation. Mud Lake is so close to Lake Washington that the two are con- nected during the winter season. It is a circular lake about 880 m. in diameter. There is some bog vegetation near its southern end, and the situation of this vegetation appears to be in a general way similar to that of Buckeye Lake bog in Ohio described by DacuNnowski (5). The water used was obtained from the edge of the lake at a distance of 90 m. or more from the bog vegetation. The well water used at Friday Harbor was obtained from a surface well near the Puget Sound Marine Station. This is called “tap water” in table I, since the effect of the two has been found to be identical. Plants were also grown in several solutions which it was expected would prove toxic. The following list of substances was found to produce stunting of the root hairs of Tradescantia of an amount and kind comparable with the effect of undiluted bog water: sea water diluted with three times its volume of tap water; carbolic acid, o.oor per cent; formalin, o.oor per cent; gelatin, 0.001 ©.002 per cent; tea; coffee. In undiluted sea water no roots developed. Stronger solutions of carbolic acid and of formalin entirely inhibited the development of roots. It is of course possible that formalin might develop from the slow decay of woody materials in the bog in the absence of oxygen, but I have not found any evidence of its presence in bog water. We might reasonably expect, also, that tannin would be found in bogs, but we have no direct evidence that it is a factor in limiting bog floras. 320 BOTANICAL GAZETTE [APRIL The effect of dilution with tap water was tried with the results shown in the following table: TABLE iat THE EFFECT UPON ROOT HAIRS oF TRADESCANTIA OF BOG WATER DILUTED WITH TAP Root HAIRS Bos St | ce EXP ae 2 * patton | oom | Sie | Maths | Noe Seattle bog. 22.2... I 3 5 aes, S, meattle bop..." .. - ie + II ie WOR eer: To 3 7 3 leroy bog ite) 3 sie) i Fauntleroy bog .... 5 r 5 se es “at Fauntleroy bog .... 10 to 3 5 4 I From this it appears that the toxin is present in such small amounts that slight dilution greatly decreases the toxic effect: This is in line with the results obtained by Livincston (7) on Stigeoclonium. Three samples of water from the Henry bog were boiled until each was reduced to one-eighth of its original volume. Tradescantia cuttings were placed in them. Few roots started, no root hairs were formed on them, and the plants soon died. The effect of filtering bog water from the Henry bog through filter paper was tried. The water was collected on October 10, 1911, and three plants were grown init. They all produced normal root hairs. A preliminary investigation was made as to the presence and activities of bacteria in the Seattle bog and the Henry bog. Briefly the results may be stated as follows. 1. Beans, peas, and corn decay just as readily in bog water as in tap water. 2. Fresh beef decays a little more slowly in bog water collected in a sterilized jar and kept sealed than it does in tap water under =o same conditions. . The amount of difference in the rate of decay of pieces of —s beef buried in bogs and of other pieces buried in swamps is very slight, it being a little more rapid in swamps. 1913] RIGG—EFFECT OF BOG WATERS 321 4. Bacteria were found in every case in both bog water and peat collected under sterile conditions. Some of the specimens of peat were collected from as great a depth as 75 cm. . 5. Bacillus subtilis and Pseudomonas liquefaciens were identified in cultures made from surface waters in the Seattle bog. TRANSEAU (9) found bog waters to be teeming with bacteria. DacHNowsKI (4, 5) has found bacteria abundant and has given his attention largely to their physiology. Apparently the position that bog waters are very strongly antiseptic is no longer tenable. Discussion Suggestions offered by three other investigators (LIvincsToN, DacuNowsk1, and Covit1e) bear on the theory stated at the beginning of this paper. In 1905 LivincsToN (7) concluded that there were chemical substances present at least in some bog waters that affected the alga that he used (Stigeoclonium) as did poisoned solutions, and that these substances are not related directly to the acidity of the water. He concludes that “the stimulating substances here demonstrated may play an important role in the inhibition from bogs of plants other than those of xerophilous habit.” In 1909 DAcHNowsKI (3) stated his belief “that there are present in bog water and in bog soils injurious Substances which are, at least in part, the cause of xerophily in plants and of decreased fertility in bog soils.” In 1910 CovILLEe (1) stated that “the swamp blueberry (Vaccinium corymbesum) grows in peaty soils which contain acid or other substances poison- ous to plants. As a protection against the absorption of amounts of these poisons great enough to prove fatal, this plant, like many other bog and acid-soil plants, is devoid of root hairs and con- sequently has a restricted capacity for absorbing soil moisture.” In 1911 DACHNowsKI (5) words his theory a little differently and speaks of “the toxicity of the habitat and its consequent physio- logical aridity and selective operation on forms striving for occu- pancy.” In the same paper DACHNOWSKI says that “the reduced absorptive capacity of the plants is not a consequence of the absence of root hairs or of a smaller absorbing surface.” é It is thus seen that Livincston suggested that bog toxins 322 BOTANICAL GAZETTE [APRIL excluded certain plants from bogs, but did not express any opinion on root hairs, while CovILLeE stated the theory that certain plants were devoid of root hairs as a protection against bog poisons, but does not give an opinion whether the bog habitat as it at present exists caused the loss of these root hairs. Neither does he express any opinion as to how mesophytic plants are kept out of bogs. It is to be borne in mind that CoviLLE was working on a specific economic problem and evidently did not concern himself, in the paper quoted, with questions of pure science. DACHNOWSKI at first thought that toxins caused xerophily in bog plants and later that the toxicity caused bogs to exercise a selective operation, but does not suggest any injurious effect of bog toxins on root hairs as the cause of such selective operation. TRANSEAU’S work (10) would seem to suggest that Larix laricina is adapted to the Michigan bogs because it can still live after the loss of its root hairs and even after the destruction of the cortical tissues of its roots. Larix, however, is not a genus that is universally characteristic of bogs as are such genera as Ledum, Kalmia, Oxycoccus, and Vaccinium. There seems to be room fot doubt as to the cause of the death of the root hairs and of the cortical tissues of the roots of Larix in the Michigan bogs. It is possible that they may be killed by a toxin and attacked by a saprophytic fungus afterward. It is also possible that they may have been killed by a parasitic fungus. Definite conclusions as to the relation of the toxicity of the bog habitat as a cause and the stunting of root hairs as a result cannot, of course, be drawn from the results obtained from the use of water from six bogs on a single species. Further work must be done with other bog waters and other plants to show how far these two things are related as cause and effect. The question of how bog plants came to be devoid of root hairs is quite a different question from that as to why mesophytic plants are now excluded from undrained bogs. DacHNowskI, who in 1909 (3) believed in the activity of bog toxins in causing xerophily in bog plants, states (5) in 1911 that “during the glacial period most species common to bogs skirted the ice sheet.” Whether these plants were under bog conditions at this time or whether their distribution was related : 1913] RIGG—EFFECT OF BOG WATERS 325 to low temperatures only does not seem to be settled. Evidently extremely low temperatures must be reckoned with as one of the factors that determine the characteristics of these plants in past ages, and the same is true of bog plants growing in the extreme north in post-glacial times. We certainly are not justified in concluding that bog conditions as they exist today in temperate regions are the cause of xerophily in bog plants. There does seem to be ground for the belief that certain plants having hairless roots and other xerophilous structures are able to live in bogs, while other plants that normally have root hairs and possess in general a mesophytic or tropophytic structure are kept out of the bogs by these toxins. It now seems well established that the inhibition from undrained bogs of plants other than xerophytes is not caused by acidity as such (H ions) (Livincston 7), nor by low osmotic pressure (LIVINGSTON 6), and that it cannot be correlated with low temperatures or strong drying winds (DAcHNowSsKI 5), or directly with lack of aeration. Although the toxic effect of bog waters does disappear with con- tinued aeration (DACHNOWSKI 2), it seems evident that the presence of air destroys the toxic substances that are present in bog water, and that the mere absence of air from water does not render it toxic. The fact that DacuNnowskI (5) found that the toxic effect of bog water can be removed by filtering it through agricultural soils and that the toxic effect was then present in the soil used as a filter seems to settle the point. Whether the toxic effect of bog waters is due to one substance or to several we do not know. Nor do we know positively that it is always due to the same substance or mixture of substances. Undoubtedly the toxic substances are organic, and the problems of organic analysis involved are beyond us at present. What the source of the toxin (or toxins) is we do not know definitely. There seem to be at least three possible sources: (a) excretion products coming into the substratum from plants growing in the bog, (b) products resulting from decay in the absence of oxygen, (c) excretion products of bacteria. Since it is probable that many other fungi are associated with the bacteria in bogs, it seems scarcely possible to distinguish sharply between (a) and (c). 324 BOTANICAL GAZETTE [APRIL Since Sphagnum is the one macroscopic plant always present in bogs, our attention would naturally be directed to that. Since the presence of Sphagnum and the lack of drainage are the two condi- tions necessary for the formation of bogs, it seems probable that in this combination is the place to seek for the production of the toxin. Bacteria, however, seem to be always present in bogs and their excretion products are to be taken into account. DacHNOwWSKI (5) finds reason for believing that bacteria are active agents in enabling peat bogs to admit certain plants and exclude others. As the same investigator (4) has suggested, the large number of chemical and biological agents present may react collectively with the results of decomposition. Since it has been found by DacHNowskI (3) that the presence of a considerable amount of a finely divided insoluble substance destroys the toxic effect of bog water, it seems possible that the absence from bogs of ordinary insoluble soil substances may be a factor in the produc- tion of toxicity in bogs. DACHNOWSKI (5) has given recently a historical summary of the theories of the causes of the xerophilous character of bog plants. In this summary he says ‘‘LiviNcsToNn suggests the presence of chemical substances not in direct relation to the acidity of the soil as acting on the vegetation. Another explanation, that of the toxicity of the habitat and its consequent physiological aridity and selective operation upon forms striving for occupancy, has been offered by the writer of this paper.’’ In the paper above quoted LIVINGSTON says “the result of these tests is, briefly, that many bog waters act upon the plant [Stigeoclonium] like poisoned solu- tions.”’ Again, he says ‘diluting the . . . . samples .. . . with distilled water or with a weak nutrient solution decreases the toxic effect.” In his summary he says “the stimulating substances here demonstrated may play an important réle in the inhibition from bogs of plants other than those of xerophilous habit.” It seems to the writer that the toxin theory of the cause of the exclusion from bogs of plants other than certain xerophytes origi- nated with Livincston. The theory has been greatly extended and a wealth of experimental data given to support it by DACHNOWSKI, 1913] RIGG—EFFECT OF BOG WATERS 325 and the present paper contributes the suggestion that the toxins act through their stunting effect on root hairs. The bog problem was suggested to the writer by Professor THEO- DORE C. FrRyYE, of the University of Wasltington, and he has had the advantage of his criticism and advice as well as that of Dr. Joun WEiNzIRL, bacteriologist in the same department. Summary 1. Tradescantia grown in bog water shows stunted root hairs. 2. Tradescantia grown in water from open lakes and springs immediately adjacent to bogs shows normal root hairs. 3. Tradescantia grown in water from drained or partly drained bogs shows almost normal root hairs. 4. The stunting of root hairs of Tradescantia by bog water is comparable with the stunting of them by exceedingly dilute solu- tion of sea water, of formalin, of tannic acid, of gelatin, of coffee, and of tea. 5. The stunting effect of bog water on root hairs of Tradescantia disappears when it is diluted with an equal volume of tap water and in some cases when diluted with one-half its volume of tap water. 6. The stunting effect of bog water on root hairs of Trades- cantia may be increased by boiling the water down to a fraction of its original volume. 7. Many typical bog plants have no root hairs. 8. There seems to be a toxin or toxins in bog water whose effect disappears with drainage of the bog. 9. Possibly this toxin inhibits mesophytes from bogs by redu- cing the amount of absorptive surface exposed by the root system. UNIVERSITY OF WASHINGTON SEATTLE, WasH LITERATURE CITED 1. Covitte, F. V., Experiments in blueberry culture. Bur. Pl. Ind. Bull. 193. IgIo. 2. DacuNowskI, A., The toxic property of bog water and bog soil. Bor. Gaz. 46:130-143. 1908. 326 BOTANICAL GAZETTE [APRIL 3. Dacunowsk1, A., Bog toxins and their effect upon soils. Bor. Gaz. 47: 389-405. 1909 , Physiologically arid habitats and drought resistance in plants. _ Bor. Gaz. 49: 325-339. 1910 5. ——,, The vegetation, of Secbedry Island (Ohio) and its relation to the subisiritem, temperature, and evaporation. Bor. Gaz. 52:1-23, 126-150. IQII 6. ee B. E., Physical properties of bog water. Bor. Gaz. 3'7:383- 385. 4. 7, Pe cca properties of bog water. Bor. Gaz. 39:348-355 905. 8. pin. C. V., Flora of Washington. 1906. 9. TRANSEAU, E. N., The bogs and bog flora of the Huron River Valley. Bor. GAZ. 40:351-375. 1905 , The bogs and bog flora of the Huron River Valley. Bor. Gaz. 41:317-42. 1906. ro. CURRENT LITERATURE ~ BOOK REVIEWS The ecology of water plants Long ago the ecological features of the hydrophytes were brought together in comprehensive fashion by SCHENCK in two admirable volumes. Recent y Dr. Huco Griicx, a young and enthusiastic investigator, has published oe volumes along similar lines, and they are very rich in detailed information; indeed, they may be regarded as encyclopedic in nature. The first two volumes, dealing respectively with the European Alismaceae and the genus Utricularia (together with an account of turion formation), have been noticed in these pages.t_ The third and thus far the largest volume, which is now at hand, is very different in scope, treating as a whole the vegetation of fresh- water banks, that is, the marginal vegetation of streams and ponds.? This vegetation is essentially that of the belts which are subject to inundation, and embraces, therefore, practically all of the so-called amphibious plants. These plants, of course, are among the most interesting of all plants to ecologists because of their plasticity. While most of the genera and many of the 124 species sate in this volume are of very widespread distribution, the author limits his studies to central and southern Europe. The work is based on almost numberless field trips to all parts of this vast region, and these observations have been backed up by numerous cultures. The author makes no pretense to completeness, suggest- ing, indeed, that these are among the most poorly known of all plants, and that they are well worthy of much more careful study; some color is given to this view by Giticx’s discovery, in these floristically best known of all lands, of tirely new areas for four different species. The author recognizes two “zones” (thus ignoring the Brussels recommendation of 1910 that the term zone be employed henceforth only for the great climatic belts of the earth), one of the land margin with leaves mostly aerial, and one of the water margin with leaves mostly submersed. The subdivision of the “zones” into groups and subgroups is based not on habitat but on leaf form. For example, “zone 1” includes a group with linear leaves (as Typha, Acorus, Iris), a group with petioled entire leaves, a group with petioled divided leaves, etc. Under each group or subgroup the species are considered individually, and under each * Bor. Gaz. 43:67-69. 1907. ? Glick, Huco, Biologische und morphologische Untersuchungen iiber Wasser- und Sumpigewiichse. III. Die Uferflora. pp. xxxiv+644. pls. 8. figs. 105. Jena: Gustav Fischer. rgrr. 327 328 BOTANICAL GAZETTE [APRIL species there is usually a further subdivision into such topics as land form, water form, submersed form, form with floating leaves, etc. The greater part of the work is taken up by the plants of the water margin (“‘zone 2”). These belong to two categories, so far as leaf form is concerned, those that are homo- blastic or with but one leaf type, and those that are heteroblastic or with two leaf types; the heteroblastic water plants are with us well represented by such plants as Siwm and Proserpinaca. Most of the plants of ‘zone 1”’ have greatly reduced water forms, many of which are generally unfamiliar, and some of which are known only from cultures; these forms rarely flower. One of the striking discoveries is a water form of a dodder (Cuscuta alba) which parasitizes Isoetes and water buttercups. Only a few of the species studied live in flowing water. The water forms seem related to low temperatures, and while the land form is essentially a summer form, it can sometimes be produced at other seasons by raising the temperature of the cultures. Most of the species have winter rest periods, but there are some species that vegetate continuously, even in countries with cold winters. Many Mediterranean species have periods of summer rest. These and many other topics are considered in the 40-page summary with which the volume concludes. The book should be in every botanical reference library, for it will serve as a compendium of general ecologi- cal information about the plants it treats. It is understood that Dr. Giiick is devoting his life to the study of water plants, and we may expect other volumes of this sort in the future—Henry C. Cow es. Plant breeding in Sweden The extensive series of experiments in plant breeding which have been conducted in Sweden, principally at the Svaléf station, beginning about 1886 and extending with ever increasing efficiency to the present time, are of great interest not only to agriculturists but also to scientists by reason of the prob- lems of inheritance which they involve. Unfortunately very scanty reports of these operations have been available in any but the Swedish language, and these publications have been, and quite rightly so, most largely concerned with practical results that were of special interest to the farmers of Scandinavia. These circumstances will make the present report? the more useful, prepared as it is by one who has carefully investigated the methods employed and the results obtained at the Swedish stations, and addressed primarily to the scien- tific reader, but in language intelligible to the general public. e report contains a brief historical sketch of the inception and develop- ment of plant breeding experimentation in Scandinavia, examples of the experi- ments with different agricultural plants, some of the results obtained, and a summary of the principles now recognized by the plant breeders at Svaléf and followed in their work. These principles are briefly: (1) the recognition 3 NewMaN, L. H., Plant breeding in Scandinavia. 8vo. = 193. figs. 63. Ottawa, Canada: Canadian Seed Growers’ Association. 1912. $1. 1913] CURRENT LITERATURE 329 that a progressive system of plant improvement cannot be a one-sided system, but must embrace all possible methods of reaching the desired end; (2) arti- ficial hybridization provides an invaluable means of obtaining characters in superior combinations which do not occur in nature and this method is now largely used at Svaléf for this purpose; (3) the old system of “mass selection” can still be of value in special cases and has never been fully abandoned; such characters, the valuation of these individuals (or lines) to rest upon tests conducted with the greatest care and extending over a series of years. This means the recognition of the importance of physiological as well as morpho- logical unit characters, and the abandonment of reliance upon the use of correlation of characters as any important aid in estimating the practical value of an individual or line. Detailed reports of some investigations, some sixty illustrations from practically all accounts hitherto written in a foreign language.””—Gro. D ULLER. The cotton plant W. Lawrence BALLs, “cryptogamic botanist” on the staff of the Khedi- vial Agricultural Society, has published a volume on the cotton plant in Egypt.‘ It brings together information of the most varied character, the material being assembled as if to “take account of stock” preliminary to a fuller monograph. The four sections of the book treat of the history of cotton in Egypt, the individual plant, the race, and the economics of cotton, the second and third sections being of special interest to botani In the account of “the individual ae, a brief outline of fertilization (including the conspicuous cytological features) and embryology is given (8 pp.), followed by an account of experimental work on “development and environment” (67 pp.). This physiological work includes such topics as germination conditions, temperature and growth, effect of sunshine, night temperatures, hypocotyl and root growth, transpiration (including its relation flowering curve, etc. The cotton fiber of course is described in detail (8 pp.). In the account of “the race,” the problems of fluctuation, commercial varieties, natural crossing, and heredity are presented (87 pp.), quite a number of graphs presenting to the eye the results of much experimental work.—J. M. C. * Batts, W. Lawrence, The cotton plant in Egypt; _ in physiology and genetics, np: xvi+202. figs. 7z. London: Macmillan & Co. rgiz. 55 330 BOTANICAL GAZETTE [APRIL Tree manuals Among the many books upon various phases of tree study two recently to hand seem well suited to the use for which they were intended. The firsts much as to the teachers and students of botany and forestry. This appeal is the more readily made through the numerous excellent illustrations, both from drawings and photographs. In the second manual‘ the same classes are appealed to, and in addition to simplicity of text and abundance of excellent illustrations, the book has further to recommend it, its pocket-size, which allows it to be most con- veniently carried into the forests themselves. The leather covered edition is in fact the best and most portable small tree manual that has yet appeared. —Geo. D. FULLER. MINOR NOTICES A sketch of Linnaeus.—Professor Epwarp LEE GREENE’ has pub- lished an admirable sketch of Linnaeus, which the publishers have presented in most attractive form. The personality of this great Swede should live be- yond the circle of professional taxonomists, and the simple and fine style of this sketch makes the booklet a most effective one for the teachers of public schools and for reading circles. The nine sections deal with the following NAEvs upon botany; LINNAEUS as a zoologist (contributed by W. H. Dat); LINNAEUS as an evolutionist. These sections introduce LrynaEus the man rather than as the father of taxonomy, and a most interesting and inspiring man he proves to be. We are told of his parentage and early education, of his struggles with adverse circumstances, and of the almost incredible 2 industry, zeal, and resolution with which he conquered and rose to high tinction. No one could introduce him more oe spiibettatially, and in better form than Professor GREENE.—J. M. C. Indiana Academy of Science.—The Proceedings of the Indiana Academy of Science for 1911 (1912), a volume of 473 pages, contains the following botani- 5 CLEMENTS, F. E., RosENDAHL, C. O., and Butters, F. K., Minnesota trees and shrubs. Report of the Botanical Suey IX. 8vo. xxi+314 (illustrated). Minneapolis, Minn.: University of Minnesota. 1912 6 Cotuins, J. F., and Preston, H. W., ect key to the wild and commonly cultivated trees of the northeastern United States and adjacent Canada. vii+184. figs. 279. New York: Henry Holt & Co. Cloth $1.35; leather $2.50. 7 GREENE, Epwarp LEE, Carolus Linnaeus. pp. 91. Philadelphia: Christopher Sower Company. 1912. 1913] CURRENT LITERATURE 331 cal papers: Some variations in plants, by F. M. ANDREWS; Report of the work in corn Solluatian (III), by M. L. Fisher; New and ectabis members of the Indiana flora, by E. J. Grimes; A eninge of the common Indiana species of Hypoxylon, by CHARLES E. OWENS; The improvement of medicinal plants, by F. A. Miter; Nutrients in green shoots of trees, by E. J. Petry; The New York apple tree canker, by Lex R. Hester; Value of fertilizing con- stituents of weeds of Indiana; analysis of ironweeds, by FRANK MATHERS and Miss Gait M. Stapp; The prevalence and prevention of stinking smut in Indiana, by C. T. ORTON; Indiana fungi — by J. M. Van Hook; Diseases of ginseng caused by Sclerotinias, by Gro. A. OSNER; pais to the flora of the Lower Wabash Valley (by Dr. J. ScHNEcK), ies CHARLES C. DEAM; Plants new or rare in Indiana, by CHARLES C. DEAM; The puma aerial forms of plant rusts in North America, by A. G. Jonnson.—J. M. C. Sylloge Fungorum.’—Volumes XIX and XX of this extended work, bearing the subsidiary title Index Iconum Fungorum, contains a oe index to illustrations of fungi, and includes references to works of m h early as well as the more recent authors. References to iho are indi- cated briefly but clearly; synonyms are introduced frequently and serve as a ready and unmistakable means of cross reference. Volume XIX enumerates alphabetically the genera A brothallus to Lysurus inclusive, and Volume XX continues with Macowanites to Zythia. The species under their respective genera and the bibliographical references thereto are likewise in alphabetical sequence, and the terminology is in accordance with the international rules of botanical nomenclature. The amount of detailed and painstaking labor involved in the achievement of such a task is enormous, but the final result in this case is a valuable work of reference, indispensable to the wis eeett and helpful to the general student of botany.—J. M. GREENMAN NOTES FOR STUDENTS Current taxonomic literature.—C. A. Dartinc (Torreya 12:155-164. 1912) has issued a “ Key to the wild and cultivated trees in autumn.” The ke is intended for use in the field for the identification of trees occurring in eastern United States—A. Davipson (Bull. So. Cal. Acad. Sci. 11:77. pl. 1. 1912) describes and illustrates a new species of Frasera (F. puberulenta) from Cali- fornia —B. O. DopcE (Mycologia 4: 218-222. pls. 62, 63. 1912) describes and illustrates a new species of Ascobolus (A. inventions) from artificial cultures *Saccarpo, P. A., Sylloge Fungorum omnium hucusque cognitorum. Vols. XIX and XX. Index Iconum Fungorum enumerans eorundem figuras omnes hucus- que editas ab auctoribus sive antiquis sive Hoorn Ductu et consilio P. A. Saccarpo. Congessit J. B. TRAVERSO. Roy. 8vo. Vol. XIX, pp. xi+1158; Vol. XX, pp. 1310. Sumptibus | P. A. SACCARDO. ts Seminarii. Patavii, 23 March Igto, and 25 May IgIl. 332 BOTANICAL GAZETTE [APRIL conducted in New York City.—J. R. Drummonp (Bot. Mag. ¢. 8451. 1912) describes and illustrates a new species of Agave (A. disceptata) supposed to be native of Central America.—A. A. HELLER (Muhlenbergia 8:82-84. 1912) in continuation of studies on the genus Lupinus records a new species (L. borealis) from the Yukon region, Canada.—W. A. Murritt (Mycologia 4: 163-160. pl. 68. 1912) under the title “Illustrations of fungi XI” describes and illus- trates several species, 4 of which are new to science. The same author (ibid. 205-217) begins a series of articles on the “‘ Agaricaceae of the Pacific Coast’; in the first article 12 new species are characterized.—C. R. Orton (ibid. 194-204. pls. 70, 71. 1912) in a paper on “Correlation between certain species of Puccinia and Uromyces” describes a new fungus (Puccinia uniporula). The type was found on Carex pubescens Muhl., collected at London, Canada.— L. QuEHL (Monatsschr. fiir Kakteenk. 22: 102-105. 1912) describes and illus- trates a new species of Echinocactus (E. violaciflorus) from Mexico.—C. REA and H. C. Haw.ey (Proc. Roy. Ir. Acad. 31: part 13. pp. 1-26. pl. 1. 1912) in a report on the fungi of Clare Island, have published a new genus (Candelspora) ; the fungus was found on leaves of J/ex aquifolia—A. REHDER (Rhodora 14:97- 102. 1912) records a new Rhododendron (R. carolinianum) from North Carolina and a hitherto undescribed form (R. minus f. Harbisonii) from Georgia.—L. W. Rippre (Mycologia 4:125~-140. 1912) enumerates 113 species of lichens, collected in Jamaica by the late Professor CLARA EATON CumMINGs; the paper includes several new combinations and 11 species new to science.—S. SCHONLAND (Rec. Alb. Mus. 2: 251-253. pl. 12. 1912) describes and illustrates a new genus (Neopatersonia) of the Liliaceae from the region of Port Elizabeth, South Africa.—R. SCHLECHTER (Rep. Sp. Nov. 10:480-486. 1912) has pub- lished 8 new species of orchids from Central America. The same author (Orchis 6:63-69. pls. 12, 13. 1912) in an article entitled “Neue und seltene Garten- Orchideen”’ describes several novelties, including a new orchid (Stelis Hen- nistana) native of Colombia.—O. E. Scuutz (Bot. Jahrb. 46:613-628. 1912) presents a revision of the genus Clibadium, recognizing 19 species, 3 being new to science.—F. J. SEAVER (Mycologia 4:115-124. pls. 66, 67. 1912) publishes the results of a taxonomic study of the genus retard recognizing 10 species of which 2 are characterized as new.—E. E. SHerFr (Rhodora 14: 164. 1912) records a new variety of Rudbeckia (R. piace var. Craigii) from Missouri.—S. A. SKAN (Bot. “Mag. t. 8436. 1912) describes and illustrates a new Calceolaria (C. Forgetii) from Peru.u—M. Stosson (Bull. Torr. Bot. Club 39% 285-288. pl. 23. 1912) has published two new ferns from tropical America. . W. Situ and G. H. Cave (Rec. Bot. Surv. Ind. 4:141-260. 1911) under the title “The vegetation of the Zemu and Llonakh valleys of Sikkim” enumerate somewhat over tooo species of plants from the Selaginellaceae to the Compositae and include a new genus, namely Parajaeschkea, referred to the Gentianaceae—W. W. Smitu (ibid. 273-282) in an article entitled “Some additions to the flora of Burma” describes several species new to science and proposes a new genus (Craibiodendron) of the Ericaceae.—A. T. SPEARE 1913] CURRENT LITERATURE 333 (Phytopathology 2:135-137. pl. 12. 1912) describes and illustrates a new fungu apionanag suffulta) , found on an unidentified species of spider at Wiamea, Hawaii.—P. C. STANDLEY (Proc. Biol. Soc. Wash. 25:119, 120. 1912) proposes a new genus (Wootonella), based on Ximenesia encelioides var. nana Gray.— F, STEPHANI (Sp. Hep. 4:801-824. 1912) has issued title-page and index to volume 4, and (ibid 5: 1-176) continues the record of species, many of which are new to science.—H. and P. Sypow (Leafl. Philipp. Bot. 5: 1133-1147. 1912) have published 24 new species of fungi from the Island of Palawan, P.I., an include the following new genera: Nematothecium of the Periporiacene & Discosiella, a genus related to Discosia.—F. THEISSEN (Beih. Bot. Ce neal 29: 45-73. 1912) under the title “Zur Revision der Gattung Dimerospori characterizes a new genus (Dichothrix) of the Eurotiaceae—W. WEINGART (Monatsschr. fiir Kakteenk. 22:83, 84. 1912) has described a new species of Echinocereus (E. Weinbergii) introduced into cultivation from North America, and (ibid. 106-109) a new species of Cereus (C. Vaupelii) from Haiti—H. F. WERNuHaM (Journ. Bot. 50: 156-164. 1912) presents a revision of the genus Ber- liera, recognizing 33 species of which 5 are new to science—K. M. WIEGAND (Rhodora 14:117-161. pls. 95, 96. 1912) presents an interesting and thorough revision of the genus Amelanchier in eastern North America, recognizing 8 species of which 3 are characterized as new. The revision is of particular value on account of a clear key to the species and full citation of exsiccatae.— W. Zen (Notizblatt 5: 268-273. 1912) has described several new species in the genus Liagora and includes one from California, one from Guadeloupe, and one from Brazil.—J. M. GREENMAN. Periodicity of tropical vegetation.—On account of the abundance of its data, VoLKENs’? report on the results of his observations in Java, 1901-1902, is perhaps the most valuable of a series of recent articles upon the problems and conditions of foliar periodicity in the tropics. Exact records of the behavior of individual trees of over 100 species growing in the Buitenzorg Gardens show almost all possible variations of foliage conditions, from trees regularly deciduous once or twice a year, through evergreens with marked Periodicity, to others with uniform foliage gradually renewed throughout the entire year. Attention is directed to the marked individuality not only of species and of individual trees of the same species, but also of individuals of different ages, and even of different branches of the same tree. VOLKENS shows that a moderate amount of climatic periodicity exists at Buitenzorg, -€specially in precipitation, relative humidity, and insolation; also that a large majority of the trees show a definite foliar periodicity, but concludes that no coincidence or causal connection can be established between the two classes of phenomena. He rejects as most improbable the influence of the salt content ts, *VOLKENs, G., Laubfall und Lauberneuerung in den Tropen. 8vo, pp. 142. Berlin: Gebriider Borndcnenes: 1912. 3.80. 334 BOTANICAL GAZETTE [APRIL of the soil water, and abandons the hypothesis that leaf-fall is due to an excess of stored food checking the activity of the leaf by preventing the removal of the products of photosynthesis. He finds the final cause of leaf-removal and leaf-renewal in the inherited, internal, unknown attributes of the protoplasm. He confesses that all his efforts to arrive at any explanation of these internal causes have been fruitless. External factors modify the action of these primary causes, but in a comparatively uniform climate like that of Java the modification is slight. VOLKENS also reviews the work of Wricut® and others upon deciduous trees, and that of SmirH™ which affords some data for certain ce species in Ceylon, and finds them in accord with his own observat n attempts to interrupt the regularity of leaf-fall, rican? in Ceylon and K1esBs® in Java removed all the leaves from individuals of various species a few months before their regular time of shedding, and obtained a prompt renewal of the foliage and its persistence throughout the period in which they were usually leafless. DINGLER sees in this a proof of the efficiency of the inner Cause in disregarding external conditions, while KLEBs, on the contrary, regards it as a response to external factors proving that a rest period is not required. Both these investigators have studied the behavior of deciduous European trees.in the tropics, DINGLER™ at a mountain station in Ceylon, and Kiess at Tjibodas, Java, and found the usual European habit largely abandoned, new foliage and flowers being often produced twice in the year, while many species never became entirely leafless. Several resembled tropical species in having at one and the same time branches in full foliage, with bursting buds and in leafless condition, respectively. From these and many other experi- mental studies KLEBs reaches the general conclusion that periodicity of plant life is conditioned by periodicity of external factors. n a more recent paper’ Kreps takes exception to VOLKENS’ statement that tropical vegetation in Java is mainly periodic, claiming that when all the constituents of the forests about Buitenzorg and Tjibodas are considered, there © Wricut, H., Foliar periodicity of Ee and indigenous trees in Ceylon. Ann. Roy. Bot. Cand Peradeniya 2:415-516. ™ SmitH, A. M., On the internal coe of leaves in tropical insolation; also observations on the periodicity of the appearance of young colored leaves of tree growing in Peradeniya. Ann. Roy. Gard. Peradeniya 4:229-298. 1909. 12 DINGLER, H., Versuche iiber die eee Soniye Holzgewiichse in den Tropen. Sitz. = Bay. Akad. Wiss. Miinchen. pp. IQII 13 KLEBS, , Uber die pntionny in der aie die Pflanzen. Sitz. Anes par Wiss. Abh. 23 r, H., Uber ea a sommergiinen Baume Mitteleuropas in iS cnokee poles Sitz. K. Bay. Akad. Wiss. Miinchen. pp. 217-247. 1911. 1s Kress, G., Uber die periodischen Erscheinungen tropischer Pflanzen. Biol. Centralbl. ae IgI2. 1913] CURRENT LITERATURE 335 is comparatively little periodicity. By a series of experimental cultures, carried on partly in Java and partly in the greenhouses at Heidelberg with tropical trees of periodic habit, he has succeeded, by varying the fertility of the soil, in obtaining varying responses from the same species and in greatly prolonging the period of continuous growth. This leads him to conclude that periodicity may be conditioned by the supply of food materials. He also calls attention to the fact that in attempts to relate periodicity to external factors only the more obvious climatic conditions have been considered, and that our data consist largely of comparatively crude observations. More exact studies nm an experimental basis are required. He concludes that the idea of a general primary rhythm in tropical plants, as advanced by ScHIMPER and now supported by VoLKENs and others, is contradicted by one series of facts, is rendered doubtful by other facts, and is supported only by such observations o the present time it has been impossible to subject to a searching physiological examination—Gro. D. FULLER Paleobotanical notes.—WueERRyY" has described three types of fossil wood from the Trias of Pennyslvania. The first, Araucarioxylon virginianum Knowlton, has been found previously in North Carolina, Virginia, and Con- necticut. The second, A. vanartsdaleni, is separated as a new species on the lower medullary rays and predominance of uniserial pitting of the tracheids. The third is referred to the genus Brachyoxylon Hollick and Jeffrey, under the hame of B. pennsylvanicum, sats ek ae pits, when uniserial, are usually poered and circular, and when either “distant and sub-opposite”’ or “alternate and hexagonal.”’ This SIE seems hardly justified, for the pits in Brachyoxylon, when double, are always alternate and closely is the formation of traumatic resin canals. Without this reaction, WHERRY cannot see refer = specimen to the genus Brachyoxylon. In a second paper,!? WHERRY discusses the evidence supporting the sug- gestion sige the Oe “New Red” may represent deposits from the Lower Carboniferous to the Jurassic, and concludes that while there are no grounds for referring any of these beds to the Paleozoic, the absence of distinctive fossils except those of the Keuper type leaves it an open question whether there may not be also Bunter below and Jurassic above.—R: S. HOLDEN Earliest European angiosperms.—Dr. Sropes has described* three new genera from the lower Greensand of England, representing the earliest struc- turally known European angiosperms. The first, A ptiana radiata, has vessels 6 Wuerry, Epcar T., Silicified wood from the Triassic of Pennsylvania. ed , Age and correlation of the “New Red” or Newark Group of Pennsyl- vania. "8 Sropes, Marte C., Petrifactions of the earliest European angiosperms. Phil. Trans. Roy. Se London B 203:75~100. pls. 6-8. 1912. 336 BOTANICAL GAZETTE [APRIL with scalariform end walls, copiously pitted fiber tracheids, both uniseriate and multiseriate rays, and very few or possibly no wood parenchyma cells. The vessels and tracheids are of an undoubtedly primitive character, but the rays, according to recent investigations, represent a high state of development. The second, Woburnia porosa, has multiseriate rays, and parenchyma groupe around the vessels, as it is in such high families as the Leguminoseae, Ulmaceae, Oleaceae, etc. The third, Sabulia Scottii, is imperfectly preserved, but shows mainly uniseriate rays. Whether they represent the primitive condition, like certain species of Alnus, or are reduced, like Castanea, Salix, Populus, etc., it is impossible to say. Dr. Stopes seems to think that.the antiquity of these specimens indicates that theirs is necessarily the primitive type of angio- spermous wood structure. It is significant, however, that in formations con- siderably older than the Lower Greensand, there are abundant impressions of the Cupuliferae, which comparative anatomy has shown to represent the really primitive conditions—R. S. HoLpEN. A new cretaceous palm.—Srevens” has described a new palm from the Upper Cretaceous of New Jersey, the fossil having been found on the beach at Seabright, not far from Sandy Hook. The details are well worked out and illustrated, and the name assigned is Palmoxylon anchorus. It seems that petrified stems of palms are not so rare as has been supposed, and the author thinks it probable that palms occur abundantly from the Upper Cretaceous on, both on the coastal plain and in the formations of the continental interior.— 1M C. Haustorium of Striga.—Miss StepHENs” has investigated the remark- able haustorium of Siriga lutea, a South African annual growing as a root parasite on native grasses and on maize. The haustoria arise exogenously from the many adventitious roots, and when one encounters a root of the maize it bores its way into the host by means of a ferment, a line of tracheids is formed down the center of the haustorium, and vascular connections are established with the host.—J. M. C 7 Stevens, N. E., A palm from the Upper Cretaceous of New Jersey. Amer. Jour. Sci. 34: 421-436. figs. 24. 1912. 20 STEPHENS, Epitu L., The structure and ee of the haustorium of Striga lutea. Ann. Botany 86310672076: pl. 03. THE BoTANICAL GAZETTE Editor: JOHN M. COULTER Ee te aie Sg NE ce. | Ta a ea MN ee rs Se aA es = : ORs, eS fi = “May 1073 i Toxicity of Smoke Lee I. Knight and Wm. Crocker # Western Plant Studies. I Aven Nelson and J. Francis Macbride 4 Sir Joseph Dalton Hooker F. O. Bower The Lichens of Mt. Rose, Nevada Albert. W. C. T. Herre Briefer Articles A New Wood-destroying Fungus Adeline Ames A Safety. Razor Modified for Cutting Hand-Sections J. P.. Givler On Stemonitis nigrescens and Related Forms W. C. Sturgis Current Literature The University of Chicago pores CHICAGO, ILLINOIS, U.S.A. Agents THE CAMBRIDGE UNIVERSITY PRESS, London and Edinburgh WILLIAM ee & SON, Sain Leipz TH. S 7a MARUZEN. ennai sacri Toke Osaka, Kyoto | The Botanical Gazette A Montbly Journal Embracing all Departments of Botanical Science Edited PY JoHN ~M. COULTER, with the assistance of ghee members of the botanical staff of the University of Chicag Issued May 15, an Vol. Ly es : “CONTENTS FOR MAY 1913, 2 aot No.5 . TOXICITY OF SMOKE.» Contamusoie FROM THE Hots ‘Boranicat kecweatony 172 ” ITH FOUR FIGURES). Lee I. Knight and Wm. Crocker - - 337 ‘WESTERN PLANT. STUDIES. I. Aveit Nelson and J. Francis Macbride - - - = She SIR. JOSEPH DALTON HOOKER. F. 0. Bower - — - i Se aig oe ty NS 5B ‘THE LICHENS OF MT. ROSE, NEVADA. Albert W.C. Tr. Herre = Pheer ee Sh OP ea re BRIEFER ARTICLES : NEw WooD-DESTROYING Funcus (WITH SIX FIGURES). Adeline Ames Pe Ok A SAFETY Razor MopiriepD FOR Cutrinc HAND-SECTIONS (WITH ONE saa. 3 J,P.Gioler 399 ON STEMONITIS IS NIGRESCENS AND AND Retarep Fors. W.C. 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Introduction (WITH FOUR FIGURES) Extensive unpublished experiments have been conducted in this laboratory to determine the reliability of the etiolated epicoty] of the sweet pea as a test for the presence of traces of heavy hydro- carbons in the atmosphere. As an outgrowth of this work, we have had occasion to study the response of this organ to smoke pro- duced by the burning of various carbon-bearing substances, with the idea of discovering the constituent or constituents that pro- duce the response. The complete statement of the response of this seedling to gas- €ous impurities will involve two additional papers, one under the title “Is methane toxic?” and the other “The sweet pea epicotyl as a delicate test for heavy hydrocarbons.’’ Both of these papers will be published shortly. NELJuBow (25) has shown that the etiolated epicoty] of the pea seedling has an abnormal growth in “laboratory” or “impure” air. We may speak of the abnormality as a triple response: change of hegative geotropism to diageotropism, increased growth in thickness, and reduced rate of growth in length. We tested about 20 varieties each of garden peas and sweet peas, and found the sweet peas in 337 338 BOTANICAL GAZETTE [may general considerably the more sensitive. Two varieties of these, under the trade names Earl Cromer and Gladys Unwin (Vaughan’s Seed Store), were especially sensitive. II. Methods GROWING THE SEEDLINGS Gladys Unwin and Earl Cromer are both hard-coated varieties. After 24 hours’ soaking in water, about 10 per cent swell, and 10 days are required for all to swell. Consequently, in order to get uniform growth in the seedlings, the coats are scratched with a file and the seeds soaked for 15 hours in distilled water. They are then thoroughly shaken up with several changes of distilled water and placed in a thin layer between sterile wet filter papers and allowed to germinate. When the longest hypocotyls have reached a length of 5 mm., the seeds are transferred to wet sterile absorbent cotton in large petri dishes and allowed to grow in total darkness at 20°-24° C. until the epicotyls have an average height of 2-3 cm. This method gives cultures fungus-free and of far more nearly uni- form growth than can be obtained by less careful methods. It also gives cultures bearing only the more vigorous seedlings. This is especially important, for sensitiveness to atmospheric impurities rises with the vigor of the seedlings. With all these precautions there is considerable irregularity in the rate of growth of the various epicotyls in a culture. The entire process must be carried on in what the German workers have called pure air, which means air practically free from the heavy hydrocarbons, especially ethylene. A quantity of this substance equaling one part in ten million of atmosphere interferes with the growth of the seedling. In case the gas to be tested is very soluble in water, it is neces- sary to protect it against contact with the moist cotton bearing the roots. This is done by covering the substratum with low- | melting paraffin mixed with pure paraffin oil. In many cases it was also found desirable to have a desiccating agent in the experi- mental chamber to keep its walls free from water given off by trans- piration. This-especially holds for gases like SO, and NH. 1913] KNIGHT & CROCKER—TOXICITY OF SMOKE 3390 METHOD OF EXPOSING TO GASES AND VAPORS‘ The exposure to gas or vapor was made in galvanized iron cans of the type shown in fig. 1, and of three capacities, 10, 50, and 100 liters. Each can consists of two pieces, the can proper and the bottom. The can proper has at a a side tube bearing a no. two-holed rubber stopper. The stopper is equipped with glass tubes, rubber tubes, and screw clamps. The lower edge of the can has an out-turned brim, 1 cm. wide, at right angles to the sides of the can; this gives the can close continuous contact with the bottom. The bottom is a galvanized iron disk with 3 mm. of the edge turned up at right angles to the plane of the disk. The brim of the can fits closely inside the upturned margin of the bottom. To seal a culture in the can, it is placed on the bottom piece, the can set in position, and the gutter above the brim of the can carefully sealed with molding clay mixed with vaseline in such propor- tions as to give the desirable consistency. The seal will hold against a very considerable un- equal pressure of gas. Vaseline was chosen as the mixing medium because it does not give off any fumes injurious to the seedlings and makes a material that maintains the same consistency after years of use. If the gas studied required the use of only a few cc., it was forced in through one of the tubes at a under a small head of mercury or water. Mercury was used in case the gas was very soluble in water, otherwise water was used. If a larger volume of the gas was required, suction was applied to one of the tubes at a, Fic. 1.—Apparatus for exposure to gases and vapors: explained in text. * The description of methods here will cover the whole field of work, thereby avoiding redescription in later papers. For that reason many matters mentioned here do not apply to the work on smoke. 340 BOTANICAL GAZETTE [MAY after which it was clamped. This suction served as the force for drawing in the gas through the second tube. In cases where very large quantities of the gas were required, as with methane, the can was replaced by a bell jar and a water ~ sealused. The whole apparatus was then placed in a dark chamber. To make sure of the reliability of the can, this method was also frequently used as a check in case of gases demanding only low concentration and not readily absorbed by water. If the vapor of a very volatile liquid, like ethyl ether, was to be used, a measured quantity of it was forced from a pipette into the upturned end of one of the glass tubes at a. A glass dish bearing absorbent cotton was attached just under the inner down-turned end of the glass tube. The liquid volatilized from the cotton and its vapor was distributed throughout the can. Applying the gases and vapors in this way, at the most distant point from the seedlings, insured that they would not at any time receive higher than the finally distributed concentration. In case the vapor of a slightly volatile liquid, like propyl alcohol, was to be applied, the desired amount was dropped on absorbent cotton and quickly sealed in the can with the cultures. In this case, of course, the clamps at @ are screwed down or the hole provided with a solid cork. The cultures are always subjected to the influence of the gas for three days, the same period used in our experiments with the carnation. At the close of an experiment the epicotyls in any culture of controls vary in height from 5 to 13 cm., while the cultures subjected to injurious concentrations of gases show less growth. In this method of experimentation, as is seen, the epicotyls are not subjected to the same concentration during the entire three days, for the gas is applied only at the beginning of the experiment. The concentration must fall to a degree varying with the different gases, due to absorption by the plant and substratum, and to some extent due to a slow diffusion outward through the seal. If the gas is one that is readily absorbed by the plant, as SO., the method probably more nearly determines the lethal dose. In the case of the carbon-bearing gases (acetylene, ethylene, propylene, methane, and carbon monoxide), with the exception of acetylene, which is 1913] KNIGHT & CROCKER—TOXICITY OF SMOKE 341 rather soluble in water, the method certainly gives a very close approximation to the constant concentration necessary to give a response. The object of the work was to determine the nature of the response given by the several gases and vapors and to approximate the concentration necessary to produce it. For this purpose the method is adequate. IIJ. Historical I. RESPONSE OF THE PEA EPICOTYL a) Horizontal nutation As has been stated, the epicotyl of the pea seedling grows pros- trate or horizontal in “laboratory” air. NELJUBOW (25) has spoken of this response as a horizontal nutation, and mentions ethylene and acetylene, both constituents of illuminating gas, as especially effective in producing it. He has shown (26), also, that the response is not limited to the pea epicotyl, but appears in the etiolated epicotyls of Ervum lens, Lathyrus odoratus, Vicia sativa, and Tropaeolum. SINGER (42) has observed the same for the potato stem. NrELjuBow has shown that the response in the pea epicotyl in an atmosphere containing ethylene varies with the concentration of ethylene. Beginning with the higher concentrations and passing to the lower, he mentions the following grades of response: (1) no growth, death; (2) no elongation, a swollen knob; (3) elongation slow, swelling, diageotropism; (4) elongation faster, little swelling, diageotropism; (5) like (4) except obliquely placed; (6) erect, but growth reduced by half The horizontal nutation has been a subject of no little investigation. With mere mention we can pass over WIESNER’S (43) conception of undulating nutation induced by darkness, and RIMMER’s (39) autonomic nutation induced by dryness, for at that time there were not sufficient data available for a rational interpretation of the response. Mo.iscH (20) and KORNICKE (17) concluded that impurities of laboratory air affect geotropic and heliotropic sensibility in opposite ways, weakening the former and strengthening the latter. MotiscH (21, pp. 170, 171) has apparently abandoned the idea of increased heliotropic sensibility. 342 BOTANICAL GAZETTE [MAY RICHTER (32, 33, 34) speaks of the impurities weakening negative geotropism and has continuously maintained that they increase heliotropic sensibility. GUTTENBURG (13) has spoken of the horizontal nutation as due to weakened negative geotropism and vigorously denied increased heliotropic sensibility. He attributes the conclusion of other workers on the latter point to inaccuracies in experimentation, especially the failure to use the clinostat, thereby eliminating the antagonistic action of gravity. NELyuBOw (26) has maintained since 1901 that the response is induced diageotropism. The evidence set forth in his last paper seems conclusive, marked as it is by excellence of experimentation. He criticizes the other workers for using “laboratory” air in which the quantity of effective impurity must vary from hour to hour, and in which the amount of impurity cannot be measured at any time. He used mixtures of pure air with 1-3 ppm. of ethylene. To maintain constant concentration the mixture was renewed daily. In this atmosphere on a horizontal clinostat the etiolated pea epicotyls showed great reduction in rate of elongation, also swelling but not bending. When grown in the same atmosphere off the clinostat, they showed the same characters with the addition of horizontal nutation. If in such an atmosphere the epicotyls were raised or lowered out of the horizontal position, they again assumed it. NELJUBOW maintains that diageotropism is the only assumption that can explain this behavior. He emphasizes that there is no autonomic nutation determining the direction in which the epicotyl turns to assume the horizontal position, but that it is entirely determined by its position in relation to the pull of gravity. RicH- TER (34), working with seedlings of Vicia sativa, V. villosa, and Pisum sativum, shows that such a statement can hold only for epicotyls more than 1cm. tall. On a clinostat or in “impure” air which “weakens” negative geotropism, the young etiolated epicotyls turn “‘backward” (in the direction in which the closed side of the curved tip faces) and crowd themselves closely against the substratum. This is an autonomic nutation incapable of manifest- ing itself off the clinostat in pure air on account of the counter- action of negative geotropism. Judging from the work of both NeELjyusBow and Ricurer, the horizontal nutation of the etiolated 1913] KNIGHT & CROCKER—TOXICITY OF SMOKE 343 epicotyl of the pea, if less than 1 cm. tall, is due to the joint action of autonomic nutation and diageotropism; but, if taller than 1 cm., it is due to diageotropism alone. It should be mentioned in this connection that NeLyusow worked mainly with taller epicotyls, which probably accounts for the autonomic nutations escaping detection by his careful methods. b) The swelling The increased diameter or swelling of a plant organ in the presence of poisons is apparently a rather commonly observed phenomenon. Cook and TAUBENHAUS (5) observed that in proper concentration of tannin the mycelia of various fungi tend to become short, thick, and much septate. GRoOTTIAN (12) finds that anaes- thetics, especially chloroform, produce a swelling in the root just back of the tip, with constrictions above and below. Né&meEc (27) finds that chloral, ether, benzine, benzene, and alcohol vapors have a similar effect. The anatomical structures of the swollen zone, along with the physiological condition causing the peculiar structure, has been a subject of some comment. As RICHTER (35) has stated, the swollen region shows an abundant development of collenchyma, also numerous rifts more or less lined with cork. RiIcHTER (36) has related the swollen condition and the development of rifts to excessive osmotic pressure induced by the poisons. So far as his cited articles are concerned, there is no evidence that he has made any measurements of osmotic pressures. His conclusions are based on two lines of indirect evidence. First, many observers have found an increase in osmotically active substances in plants grown in an atmosphere bearing poisons. JOHANNSEN has shown that soluble sugars increase in plants in the presence of ether and other anaesthetics. PRIANISCHNIKOW (29) has shown that etiolated lupine seedlings grown in laboratory air have a much greater amount of asparagin than those grown in pure air. The following table (p. 344) gives the difference, in percentage, wet weight, of asparagin in 12-day seedlings in pure air and laboratory air. Grare (10) has shown that soluble sugars accumulate in plant - organs at the expense of starch in an atmosphere bearing formalde- 344 BOTANICAL GAZETTE [May hyde. GRraAFE and RICHTER (11) have lately demonstrated that an atmosphere bearing acetylene or carbon monoxide changes radically the course of metabolism in various plant organs. In seedlings of Vicia villosa and V. sativa and stems and tubers of the potato, carbon monoxide (0.038 to 0. 29 volume per cent in air) causes an increase in the sugar and amino content. In fatty seeds (squash and mustard) there is a decrease in sugar and amino com- pounds and an increase in glycerine and fatty acids. Acetylene interferes with the synthesis of sugar from glycerine and condensa- tion of glycerine and fatty acids to fats. PURE AIR LABORATORY AIR Cotyledon | Epicotyl Cotyledon | Epicoty! 0.140 | 0.289 0.348 | 0.625 The second evidence that RicHTER offers for poisons causing increased osmotic pressures is the fact that they often produce proliferation of sublenticular tissue similar to the substomatal pro- liferations or intumescences caused by high humidity. Very often, also, the lenticular protrusions, as well as other tissues, show guttation in the presence of poisons, which RicHTER interprets as indicating high osmotic pressure. Measurements of osmotic pressure would certainly be more to the point in the case of pea seedlings, though they might give less ground for philosophy and even a reverse conclusion. Aside from known relations to osmotic pressure, and only indirectly bearing on the point under discussion, it is well known that poisons, especially atmospheric impurities, produce considerable alteration in the structure and form of plants. The late work of GaTIN (8, 9) on the effect of tarred roads on vege- tation furnishes excellent examples of this. He finds that the fumes of tar bring about the disappearance of endodermis, altera- tion in the size and number of layers of cells in the cortex and other regions of the stem, and the transformation of doubly compound leaves into singly compound ones. Of less fundamental importance, perhaps, is the disappearance of starch and the formation of cork on leaf organs and young stems. RICHTER (37) has lately 1913] KNIGHT & CROCKER—TOXICITY OF SMOKE 345 summarized the effects of poisons upon the development of plant structures. Under modifications due to increased cell pressure, he mentions inhibition of growth in length, favoring of growth in diameter, splitting of the tissues with formation of rifts, lenticular and intumescence formation, and maceration in the living body. Other modifications that he relates to the rise of turgor are collenchyma formation, thickening of the epidermis, vacuolization of the nucleus, and fusion of the nuclei. These two lines of general evidence are very interesting in con- nection with the response of the pea seedling, but after all they leave essentially untouched the real solution of the physiology of the response. This becomes more evident when it is remembered that our work shows three distinct types of response of this seedling to atmospheric impurities: (1) that produced by ethylene, acetylene, propylene, illuminating gas, various sorts of smoke, and possibly methane, and characterized by decreased rate of elongation, swel- ling, and diageotropism; (2) that produced by ether, chloroform, benzol, toluol, thiophene, xylol, cumene, and other substances, and characterized by decreased rate of elongation and swelling but not diageotropism; (3) that produced by ethyl alcohol, propyl alcohol, pyridine, hydrogen sulphide, hydrogen chloride, and other sub- stances, and characterized by decreased rate of elongation, but neither swelling nor diageotropism. A careful detailed study of osmotic pressure, permeability, and metabolic (enzymatic, acid, respiratory, etc.) behavior of the seedlings, in each group of poisons might throw much light on the internal intimate physiology of the three types of response. A detailed study in this line might also relate diageotropism more closely with physical and chemical - characters of the organ. This organ furnishes especially desirable material for such a study because of the ease with which it is changed from a negative to a diageotropic organ. 2. EFFECT OF TOBACCO SMOKE Mottscu has shown that tobacco smoke is extremely toxic to many plants. In his first paper (22) he reports the effect of tobacco smoke on various seedlings and microorganisms, and in a second paper (23) the effect upon adult plants. A third paper (24) 346 BOTANICAL GAZETTE [MAY brings together all the main conclusions of the work, and empha- sizes the bearing of the findings upon the growth of plants in dwel- lings, laboratories, etc. Seedlings (Vicia sativa, Pisum sativum, Cucurbita Pepo, Phaseolus vulgaris, and others) are very sensitive to tobacco smoke. In its presence Vicia sativa epicotyls show what we have termed the triple response, also they fail to develop anthocyanin, a feature RICHTER (38) has observed for many plants grown in laboratory air. MOLISCH states that one to three whiffs of cigar or cigarette smoke in a 4.3-liter container caused the triple response. Smoke of paper, straw, and wood has effects similar to tobacco smoke, while fumes of nicotine have little influence on the seedlings. Carbon monoxide, pyridine, and hydrogen sulphide, in considerable dilution in the atmosphere, produce effects similar to smoke. MOLIScH quotes Pontac as showing that cigar and cigarette smoke bear consider- able quantities of carbon monoxide. On the basis of these data, Mottsc# concludes that carbon monoxide is probably the con- stituent determining the toxic limit of tobacco smoke for seedlings. Acquaintance with the work of Netjuspow (25), CrocKEeR and Kwnicut (6), and LEHMANN (18) should have led him to recognize the high toxicity of ethylene for epicotyls of seedlings and other plant organs, the rather low toxicity of carbon monoxide, and the universal presence of ethylene in tobacco smoke. This immediately suggests the probability of ethylene being the constituent determin- ing the toxicity for seedlings. Motiscn’s ‘whiff’? methods are poorly adapted for matching the amount of carbon monoxide in the applied smoke against the amount demanded to produce the response. Many microorganisms are likewise remarkably sensitive to tobacco smoke. A whiff of tobacco smoke blown across a culture of Pseudomonas lucifera “puts it out” in o. 5-1 minute. It readily recovers its power to phosphoresce when returned to sea water. Chromatium vinosum, Beggiatoa, Spirillum sp., Amoeba, Vorticella, Paramoecium, Didymium nigripes, and Gymnodimium fucorum are very sensitive to tobacco smoke, while Pinnularia and Phycomyces nitens are rather resistant. Adult vascular plants behave variously toward the impurity. 1913] KNIGHT & CROCKER—TOXICITY OF SMOKE 347 Tradescantia guianensis, Selaginella Martensii, Tolmiaea Menziesii, Eupatorium adenophorum, and various echeverias are not inter- fered with at all by low concentrations of smoke in the air, and only slightly inhibited in their growth by great concentrations. The mature plants that are sensitive to tobacco smoke manifest it in three ways: (1) by chemotactic movements of the leaves; the leaves of Boehmeria utilis and Splitgerbera biloba showed epinastic move- ments when in a glass chamber of 4.5~-7 liters with 1-3 whiffs of cigar or cigarette smoke; in Boehmeria the movement continues beyond the vertical position, with the formation of spirals in the petiole; (2) by lenticular protuberances; the development of lenticular protuberances occurred in sprouts of the potato and stems of Boehmeria polystachya and Goldfussia glomerata in the presence of tobacco smoke; while in Salix rubra and Sambucus nigra such protuberances develop in moist air, the process is greatly hastened by tobacco smoke; guttation commonly occurs in this lenticular tissue, due, as Moxiscu assumes, to high osmotic pres- sure; (3) by fall of leaves; tobacco smoke causes leaf fall in many plants; this is especially true of leguminous forms; 24-48 hours of exposure to tobacco smoke causes almost complete loss of leaves in Mimosa pudica, Caragana arborescens, Robinia pseudacacia, Halimodendron argenteum, and others; paper and wood smoke were likewise very effective in producing leaf fall, and nicotine very weakly so. Moxtscu states that in the mature plants he was not able to determine the constituent of tobacco smoke that does the injury. IV. Observation and experimentation AN OBSERVATION A mishap in the greenhouses of this laboratory has some of the virtues of a real experiment. An attempt to kill the insects by the common method of burning tobacco stems resulted in the acute poisoning of many of the plants. This application of a high concen- tration of smoke for a short time did not, of course, show responses in the nature of nasties, swellings, abscissions, and nulled tropisms, as observed by Mottscu with the application of lower concentrations 348 BOTANICAL GAZETTE [MAY for long periods. The injury in this case must be stated in terms of the region and extent of killing. The records were taken five days after the mishap. : The following showed no injury: Bryopnytes, Marchantia polymorpha, Conocephalus conicus (not under spray); PTeERI- DOPHYTES, Cyrtomium falcatum, Azolla caroliniana, Salvinia natans; SPERMATOPHYTES, cycads, when not actively growing (Dzoon edule, D. spinulosum, Zamia floridana, Macrozamia Miquelii, Encepha- lartos cycadtfolia, E. Lehmanit, E. Altensteinit, E. horridus, E. caffer, and Ceratozamia mexicana), Hibiscus rosa-sinensis, Zebrina pendula, Begonia semperflorus (flowers and foliage), Pelargonium zonale, Ficus elastica, F. lyria, Sagittaria variabilis, and Lemna trisulca. The following forms showed evident injury: BRYOPHYTES, Riccia (in pots on benches, all killed), Conocephalus conicus (grow- ing under spray, all killed); PrertpopuHytes, Lygodium sp. (leaves all killed at tips and margins and many halfway back), Pteris longifolia cristata (tips and margins of leaves killed, brown spots on leaves), Nephrolepis bostoniensis (slight injury), Aspidium longi- folium and A. nidus (some of the plants killed to the ground), Alsophila denticulata (badly injured); SPERMATOPHYTES, Impatiens Balsamina (all the older leaves brown-spotted), tomato (leaves entirely killed in most cases, but only at the tip in some), Persia gratissima (older leaves all killed), Stevia serrulata (all but youngest leaves killed), Vinca alba (ends and margins of leaves slightly injured), Coleus spp. (all older leaves fallen, young plants showed less injury). It is of interest that Conocephalus conicus growing on the benches was not injured at all, while a vigorous culture that had been growing for a long period under a spray was completely killed. It is possible that good water supply caused the development of a loose, poorly protected structure. It is likewise possible that the great surface of the spray water kept it nearly saturated with the poison of the smoke. From the data given above, one can see that in general the better cutinized forms are more resistant. Some will be interested in comparing these injuries with those from illuminat- ing gas observed in a greenhouse by Witcox (44). There is evi- dence to indicate that both injuries are due to a common substance, as we willsee later. In the case reported by Witcox, the poisoning 1913] KNIGHT & CROCKER—TOXICITY OF SMOKE 349 was more acute, due to longer application and possibly to greater concentration of the toxic material. EXPERIMENTS We will publish only a type experiment under each head, but in every case the experiment has been repeated several times to make sure the type experiment tells the truth. As has already been stated, we used the etiolated epicotyl of the sweet pea as the plant organ for testing the toxicity of smoke and its constituents, for we learned from our earlier experiments its behavior toward a great number of gaseous impurities, including the main constituents of smoke. This renders the determination of the constituents fixing the toxicity of smoke a simpler matter. Since the responses of the seedling to certain smokes and the variation of response with con- centration is similar to the behavior toward ethylene, it is well to have in mind Netjuspow’s (26) statement of the six types of response, varying with the concentration of the ethylene. They will furnish the data for an interpretation of the experimental results given below. Beginning with the higher concentrations, the responses are: (1) no elongation, death; (2) no elongation, - vertical position, a knoblike swelling; (3) considerable elongation, swelling, horizontal position of the growing swollen part; (4) elonga- tion greater, little swelling, horizontal position of part grown in ethylene-containing atmosphere; (5) like (4) except obliquely placed; (6) erect, but elongation rate reduced by half. Our fail- ure to get a strictly horizontal position in many cases where NEL- JuBOw obtained it may be due to the fact that he changed the gas every day, thus maintaining an essentially constant concentration, while we applied the gas once and allowed it to stand for three days. The gradual absorption of the gas by plant, substratum, etc., may dilute it so that the epicotyl partly recovers its upright position. For our purpose, however, one application of the gas is adequate. Experiment I.—Effect of unwashed smoke When the experiment was set up, the etiolated epicotyls (Gladys Unwin) were 2-3 cm. tall, slim and vertical. The duration of exposure was three days. The following data show the sorts and 350 BOTANICAL GAZETTE [MAY concentrations of the smokes used, along with condition of the Les at the close of the experiment: . Check (in duplicate) in 10-liter chamber; epicotyls 6-11 cm. tall, ver- that ial slim. 2. Lighted cigarette sealed in 1o0-liter chamber; epicotyls 2.5-3.5 ¢ long; swelling o.5-1 cm. long; shorter swelling vertical and longer ones declined as much as go°. 3. Lighted pine splinter in 5o0-liter chamber; epicotyls 3-5 cm. long; swelling 1-2 cm.; declination 50°—90°. 4. Lighted piece of linen paper (not giving lignin test) in 1o-liter chamber; epicotyls 3-3. 5 cm. long; swelling knoblike; no declination. . Alighted sheet of ashless filter paper (6cm. diameter) in ro-liter chacibér. seg 1-2 cm. long; swelling 1-2 cm.; declination 60°-go°. 6. Two lighted straws (12 cm. long) partly burned in 1o-liter chamber; aati 3-3.5 cm. long; swelling knoblike, ‘to rem. long; declination 0°90”. . Three whiffs of cigarette smoke in 1o-liter chamber; reaction almost Sedid with 6. 8. o.13-gm. linen paper burned as open sheet in 10-liter chamber; epicotyls 3-5 cm. long; swelling 1.5-2.5 cm.; declination 60°-go°. g. ©.06-gm. linen paper burned in 10-liter chamber; epicotyls 4-7 cm. long; no swelling; diameter everywhere greater than in checks; declination o°-15°. 10. 0.09-gm. linen paper burned in 1o-liter chamber; reaction about the * same as 9. I. 1245-gm. linen paper burned in too-liter chamber; epicotyls 2. 5-3-5 cm. long; swelling o.5-o.75 cm.; slight declination. 12. 1.45-gm. linen paper burned in 50-liter chamber; reaction about as II. 13. ©. 36-gm. linen paper in 100-liter chamber; epicotyls oe 5 cm. long; no swelling, but larger diameter than checks; declination 20°-40°. From this experiment it is evident that the smoke from the cellu- lose and lignin compounds is rather toxic. In agreement with Mottscu, it shows that the toxic effect of tobacco smoke is not due to substances peculiar to tobacco, but is as marked for the smoke of pure cellulose. The unwashed smoke from 0.13 gm. of cellulose in 10 liters gives a response lying between NELJUBOW’s responses 3 and 4. Experiment II.—Effect of washed smoke In preparing the smoke, the cigar or cigarette (tobacco or paper) was smoked by suction and the smoke washed through two special wash bottles, one containing 15 per cent H,SO,, the other 40 per cent NaOH. According to LEHMANN (18), the first removes all 1913] KNIGHT & CROCKER—TOXICITY OF SMOKE 351 NH,;, nicotine, tar, and solids, while of course the latter removes CO, and HS. There results a mixture of colorless gases which is stored over water. This method of storage is adequate, since the most toxic constituent of the smoke is very slightly soluble in water, as shown by the slight fall in toxicity when thus stored, also by evidence given later in the paper. To obtain the cigarette smoke used in the following experiments, 7 Murad cigarettes, weighing 1.3 gm. each, were two-thirds con- sumed, with a yield of 10 liters of gas. Each liter of smoke, there- fore, results from the smoking of 0.6 gm. of cigarette; 20 liters of cigar smoke were produced by 15 gm. of cigars; each liter of smoke required 0.75 gm. of cigar. The paper smoke was derived from a cigarette of bond paper not giving lignin tests; 4 liters of smoke were produced from 1.4 gm. of paper; each liter was derived from 0.35 gm. of paper. So far as we know, the tobacco and paper smoke thus washed will contain, in common, nitrogen of the air drawn through in smoking, more or less unused oxygen, certain dry dis- tillation gases of the carbon compounds involved (methane, ethy- lene, acetylene, and carbon monoxide), and perhaps higher homo- logues of methane, ethylene, and acetylene. The tobacco smoke will contain in addition traces of pyridine and perhaps other com- pounds. In this experiment the epicotyls in each culture at the beginning of the exposure varied from 2 to 3 cm. in height. The seedlings were subjected to the smoke for three days in total dark- hess at 20° to 24° C. The following data give the various concentra- tions and varieties of smoke used, along with the condition of the epicotyls at the close of the experiment. 1. Check culture in so-liter chamber; epicotyls 6-12 cm. tall, vertical and very slim. 2.2 25 cc. of cigar smoke (output of 0.0188 gm. of cigar) in 50-liter chamber; epicotyls 4-7 cm. tall; greatest declination 30°; no swelling; greater diameter than check. 3. 50 cc. cigar smoke (output of 0.0375 gm. of cigar) in 50-liter chamber; epicotyls 3. 5-4. 5 cm. long; swollen; declined portion 1.5-2.5 long, with a declination of 75°-90°. 2In all the work the smoke was measured under existing atmospheric pressure. No corrections for barometric pressure and temperature were deemed necessary, for a doubling of the concentration was required to give noticeable differences in response, hence the errors of this method were far beyond detection by the seedling. 352 BOTANICAL GAZETTE [May 4. 100 cc. cigar smoke (output of 0.075 gm. of cigar) in 50-liter chamber; epicotyls 3.5-4cm. long, with swollen regions 0.75~1.5 cm. long; swollen zones varying from upright to horizontal; the shorter sens upright zones indicate that there i is no growth in length. $430 cc. sows smoke big at of 0.097 gm. of cigar) in 50-liter chamber; many epicotyls showed | llings; no growth in length and no declina- tion; many others were dead. 200 cc. cigar smoke (output of 0.15 gm. of cigar) in 50-liter chamber; Sacityis mostly dead; living ones vertical, with a knoblike swelling; no grow in length 7. 330 cc. of cigar smoke (output of o. 25 gm. of cigar) in 100-liter anher condition of epicotyls between that of 5 and 6. 8. 40 cc. of cigarette smoke (output of 0.024 gm. of cigarette) in 1o-liter chamber; epicotyls 3-4. 5 cm. long; swollen zone 1-2 cm. long; declination of swollen portion 80°—go0°. g. 20 cc. of cigarette smoke (output of 0.012 gm. of cigarette) in 1o-liter chamber; epicotyls aed cm. long; swollen portion 2-3 cm. long; declination of swollen part 70°90". occ. cigarette smoke (output of 0.006 gm. of cigarette) in ro-liter seers epicotyls 4-9 cm. long; little declination; no swelling; diameter of epiotyls greater than that of checks. . 20 cc. paper smoke (output of 0.007 gm. of paper) in 1o-liter chamber; ecivte 3-4.5 cm. long; swelling 0. 75-1. 5 cm. long; swollen portion vertical to horizontal. 12. Io Cc. paper smoke (output of 0.0035 gm. of paper) in ro-liter chamber; epicotyls 4-5 cm. long; swelling 1-2.5 cm. long and declined 70°-go”. Several things are evident from these experiments. The smoke of paper and tobacco cigarettes is still very toxic after thorough washing with 15 per cent H,SO, and 4o per cent NaOH. Later data will show that the constituents thus washed out have a com- paratively low magnitude of toxicity. It becomes probable then that the high toxicity of paper and tobacco smoke is determin by the dry distillation carbon-bearing gases. Figuring on the basis of 1o-liter containers, 10 cc. of cigar smoke (output of 0.0075 gm.), 40 cc. of cigarette smoke (output of 0.024 gm.), and rocc. paper cigarette smoke (output of 0.0035 gm.) give the third response mentioned by NELJuBow (reduced rate of elongation, swelling, and horizontal position of the swollen part). On the basis of the amount of washed smoke necessary to give the response, the cigar and paper cigarette smokes are about equally effective, and the tobacco cigarette smoke about one-fourth as 1913] KNIGHT & CROCKER—TOXICITY OF SMOKE 353 effective; while on the basis of the dry weight necessary to produce the smoke, the paper is more than twice and the cigarette only about one-third as effective as the cigar. The toxicity of the several smokes undoubtedly depends in part on the oxygen supply during the smoking. This will determine to some degree the amount of dry distillation gases escaping oxidation, although much of these will escape oxidation under any condition, for the heat is sufficient beyond the ignited portion of the cigar or cigarette to cause dry distillation, and here no burning of the dry distillation gases can occur. When the same paper used in making the paper cigarettes was burned as an open sheet in the 1o-liter container, it required 0.14-0.21 gm. to give NELJuBOW’s third response. When burned in this way, the paper smoke is approximately 0.02 as toxic for this seedling. Burning the open sheet insures a more complete oxida- tion of the dry distillation carbon-bearing gases, both because of better oxygen supply and because of surer contact with the flame. It should be stated that the paper cigarettes used, though rolled only to moderate tightness, were difficult to smoke in the machine. They required considerable more suction than the cigarette and probably had low oxygen supply, as later analyses will indicate. Experiment III.—Effect of washed smoke and chemical analyses Two paper cigarettes, one loosely rolled and the other tightly, were smoked and washed with 15 per cent H,SO, and 4o per cent NaOH and stored separately. The analyses of this sort of smoke according to the methods described by HEMPEL (14) are as follows: Loosely wrapped paper cigarette; 4.78 gm. of paper smoked, with a yield of 8384 cc. of washed smoke. A B Volume of smoke taken for analysis..........-: 99.6 ce 99.9 cc. Volume after absorption with 4o per cent NaOH. 6 99-9 Volume after absorption wit bes 2 oe es 99-5 99-9 Volume after absorption with phosphorus... ..... 99.5 99-9 Volume after absorption with ammoniacal cuprous| MOE ka ce tas eva eee de 84.4 85.0 Volume 66 00,5 is. isis ie a 15.1 nite 354 BOTANICAL GAZETTE [MAY This analysis gives a trace of heavy hydrocarbons (bromine- absorbed gases) and approximately 15 per cent of carbon monoxide. The figures show that each gram of paper produced 263 cc. of CO. This yield is very high when compared with the yield from tobacco in cigarettes, cigars, and pipe as reported by LEHMANN (18). In these it varies from 15 to 101 cc. of CO per gram of tobacco. Our figures may be a little high, due to incomplete drying of the stub before weighing. Tightly wrapped paper cigarette. In this case 3.41 gm. of paper produced 7357 cc. of washed smoke. Analysis - . Volume of smoke taken for analysis ............ 07.6 cc cc Volume after absorption with 40 per cent NaOH 5.8 90.6 Volume after absorption with phosphorus ....... 95.8 9 Volume after absorption with bromine water 95.8 Volume after absorption with ammoniacal cuprous| Pee ene re es ks 81.1 77.9 ek oe kes eae 14.7 13.6 In this analysis considerable CO, appears. On the basis of the CO,-free smoke the CO constitutes 15+ per cent, approximately the same percentage shown in the analysis of the loosely rolled cigarette. There is not a measurable amount of heavy hydro- carbons, but in an analysis like this, where no corrections are made for temperature changes, it is possible to leave undetected o.2 cc. In this case each gram of paper produced 327 cc. of CO, an even higher yield than given by the loosely rolled cigarette. This too is probably a little high, due to insufficient drying before weighing the stub back. Effect on the seedlings —At the beginning of the experiment the epicotyls were 2-3 cm. tall. The cultures were sealed in 10-liter cans and subjected to the smoke for 3 days. The. following data show the nature and concentration of the smoke used, along with the condition of the seedlings at the close of the experiment. 1. Check; epicotyls 5-13 cm. tall, vertical and slim. Washed smoke from loosely rolled paper cigarette 2, 20 cc. ; cores: 3.5-5 cm. long; swollen portion 1-2 cm. long, with declination of 75°-90°. ~ 1913] KNIGHT & CROCKER—TOXICITY OF SMOKE 355 OCs and he 3-4.5cm. long; swollen portion 1-1.5 cm. long, wih. declination of.75°—90 4. 50CC.; epicotyls 3-4 cm. long; swollen portion o.5-0.75 cm. long, with little or no declination. Washed smoke from tightly rolled paper cigarette occ; a 3-4.5 cm. long; swollen portion 1-1. 5 cm. long, with declination of 7 6; 20 Ce.; epicotyl & 5 cm. long; swollen portion 0.75-1.5 cm. long, with ane ta of 75°- TREC: ee Chay 3-4 cm. long; swollen portion o.5-0.75 cm. long, Ww ith little or no declination. It appears from these experiments that the tightly rolled cigarette gives slightly the more toxic smoke, though not markedly Fic. 2.—Responses to paper smoke: a, check; 5, response to 10 cc. of smoke from loosely soiled paper cigarette in 10-liter chamber; ¢, response to 20 cc. of smoke. so. In both sorts of smoke 10-20 cc. in 10 liters gives NELJUBOW’S third response, while 50 cc. in ro liters gives his second response. It is apparent that considerable variation in concentration is necessary before a noticeable difference in response is shown. Even doubling the concentration may modify the response only slightly. This condition holds for ethylene, carbon monoxide, and a number of other gases, as our later paper will show. On the other hand, with pyridine, ethyl and propyl alcohol, acetylene, and others, rather slight variation in concentration is evidenced by very noticeable differences in the response. A series of photographs will give a more vivid idea of the response to smoke. Figs. 2 and 3 show the response to various concentrations of paper smoke. 356 BOTANICAL GAZETTE [MAY Experiment IV .—Effect of bromine absorption on the toxicity of paper smoke In this experiment the washed smoke from the loosely rolled paper cigarette was absorbed with bromine by the gas analysis method described by Hempet. All traces of bromine were later absorbed by washing with 40 per cent NaOH. As is well known, bromine absorbs the heavy hydrocarbons (acetylene, ethylene, etc., with their higher homologues). It does not absorb methane or carbon monoxide. If the substance determining the toxicity of this smoke is one of the heavy hydrocarbons, this treatment should reduce the toxicity. If it is carbon monoxide or methane, it should not greatly modify the toxicity. The cultures were sealed in 1o-liter Fic. 3.—Responses to paper smoke: a, check; }, response to 20 cc. of smoke from tightly rolled paper cigarette in 10-liter chamber; c, response to 50 cc. of smoke. chambers and subjected to the various sorts and concentrations of smoke for three days. The data show the condition of the epi- cotyls at the close of the experiment. 1. Check; epicotyls 5-11 cm. tall, vertical and slim. 2. 20 cc. washed smoke not absorbed with bromine; epicotyls 3-4. 5 cm. long; swollen portion 1—1.5 cm. long, with declination of 75°-90° 3. 25 cc. (duplicates) washed smoke absorbed with bromine; epicotyls 6-12 cm. tall, vertical and slim. 4. 85 cc. washed smoke absorbed with bromine; epicotyls 4-9 cm. tall, vertical and slim. 5. 69 cc. washed smoke absorbed with bromine; epicotyls 4-9 cm. tall, slim and straight. r913] KNIGHT & CROCE Teter OF SMOKE 357 c. washed smoke absorbed with bromine; epicotyls 37 cm. long; no seling and little declination. 7- 550 cc. washed smoke absorbed with bromine; epicotyls 3-5 cm. long; saiellivig 2-3 cm.; declination 10°-60°. It is evident from this series of cultures that absorption with bromine greatly reduces the toxicity of paper smoke and shows that substances belonging to the heavy hydrocarbons are the ones determining the toxic limit. _The response given with 550 cc. of bromine-washed smoke is probably due to the CO, for that amount of smoke contains about 82 cc. of CO. Experiment V.—The effect of coal smoke The smoke was withdrawn from the furnace of a large flat building on a cold day, when large volumes of soot-free air were pouring from the chimney. The smoke showed the following analysis. Vohume atisivred sc. ha 93-6 cc. 99.3 Cc. Aiiter: NaOH. a oes os Se ered oS esG g2.2 97.6 Difference=CO,+S0,........:.. 1.4 r.7 92.2 97.6 Adter phosphorous: . i455 9-5 75.8 80.2 Differentes Oy 3 . a ve Ie 17.4 75.8 80.2 After ammoniacal cuprous chloride 75.6 79.9 Difference=CO.........- hie 0.2 0.3 This smoke contained about 1.6 per cent of CO, and SO, together; long storage over water had probably reduced somewhat the percentage of these gases. The oxygen was reduced to a little less than 18 per cent, while only a trace of CO was present. The following data report the results from exposing the test seedlings to various concentrations of this smoke. Part of these cultures were run in water-sealed bell jars and part of them in cans. At the beginning of the experiment the epicotyls were 2-3 cm. long, and after every exposure were slim and straight. 1. Control; epicotyls 6-12 c 2. 20 cc. in ro-liter chamber; ree 6-13 cm, tall, 358 BOTANICAL GAZETTE [MAY 50 cc. in 1o-liter chamber; epicotyls 6-13 cm. tall. 500 cc. in 1o-liter chamber; epicotyls 5-10 cm. tall. One liter in ro-liter chamber; epicotyls 4-9 cm. tall. Three liters in 6 liters; epicotyls 3-7 cm. tall. Two liters in 6 liters; epicotyls 3-7 cm. tall. oe eS It is evident that the chimney smoke is very slightly toxic. In one-half an atmosphere of this smoke the epicoty] is less inhibited in growth than in one part in 1000 of the smoke from the loosely rolled paper cigarette. This shows that the latter smoke is more than 500 times as toxic as the coal smoke used. In commercial furnaces it is customary to supply just enough air to oxidize com- pletely all gases. Any considerable excess adds to the volume of heated air passing out of the chimney and to an economic loss from this source. It is in this that the flat-owner can be criticized rather than the point in question, the addition of poisonous carbon-bearing gases to the air, for his furnace was receiving about 1o times the volume of air necessary to give complete combustion. High. oxygen supply probably accounts for the small amount of reduced carbon-bearing gases and for the low toxicity of the smoke. It is an open question in commercial furnaces, where there is little excess of oxygen, whether there is a sufficient amount of these gases to play any part in the injury of vegetation, as SEARLE (41) has sug- gested. In general, the injury from coal smoke has been attributed entirely to tars and the oxides of sulphur. It is certain, however, that carbon-bearing gases, especially ethylene, might be in sufficient concentration to do injury and still be in too small quantities for detection by chemical methods (14, p. 257). A full discussion of this point is given in the last section of this paper. Effect of the various constituents of smoke The experiments already recorded afford evidence that the heavy hydrocarbons determine the toxic limits of tobacco and paper smokes. It is desirable, however, to know the magnitude of toxicity of the several constituents, also the nature of the response produced in the epicotyl by each. Moreover, it is desirable to de- termine the particular hydrocarbon responsible. For paper smoke this will demand the study of ethylene, propylene, acetylene, 1913] KNIGHT & CROCKER—TOXICITY OF SMOKE 359 methane, and carbon monoxide, and in tobacco smoke pyridine, ammonia, hydrocyanic acid, and nicotine in addition, leaving entirely out of consideration the tars which have a relatively low toxicity where only their vapors are involved, and probably no such . a magnitude of toxicity under any conditions as several of the carbon-bearing gases. Of these substances we will give detailed experiments only on carbon monoxide, hydrocyanic acid, and nicotine. For the other substances it will suffice merely to cite a portion of a table to appear in one of our later papers, along with the details from which it is derived. We consider the details on carbon monoxide here because it is the more abundant toxic gas and because Moriscu suggests that it may be the one rendering the smoke so toxic to seedlings. Experiment VI.—Effect of carbon monoxide It is first desirable to make sure that the carbon monoxide used is free from the noxious gases, or at least that the effect produced is due to the contained CO and not to some impurity. For this reason the carbon monoxide was generated by three different methods and the three products compared as to their effects. It is assumed that if equal amounts of the three sorts of gas produce equal effects, the effect is due to the CO and not to impurities. Since the heavy hydrocarbons are so toxic, it was thought well to see whether washing the CO in bromine would reduce the toxicity. When oxalic acid was heated with several times its weight of concentrated H,SO, and washed with 40 per cent NaOH, a gas resulted which gave (duplicate analysis) 99 per cent absorption with ammoniacal cuprous chloride. Potassium ferrocyanide was heated with 8-10 times its weight of concentrated H,SO, and washed with 40 per cent NaOH. In duplicate this showed 96 per cent CO. Sodium formate was heated with concentrated H,SO,and produced a gas giving 89 per cent absorption with ammoniacal cuprous chloride. The epicotyls were 2.5-3.5 cm. tall at the beginning of the experiment and were inclosed in 1o-liter cans. The following data show the sources and concentrations (correcting for impurities) of CO used, and the condition of the seedlings at the close of the experiment. 360 BOTANICAL GAZETTE [MAY 1. Check; epicotyls 6-11.5 cm. tall, vertical and slim. a) Potassium ferrocyanide-derived CO . 50CC.; epicotyls 4-6.5 cm. long, with declination of 20°-45°; seahius but larger diameter than checks. 3- 100 cc.; epicotyls 3-5 cm. long; swelling 1-2 cm. long, with declination of 70°90". &. 200, Ct.; epicotyis 2.5-4.5 cm. long; swelling 1-1.5 cm. long, with declination 80°—90 5. IOocc. Rater in bromine; epicotyls 3-5.5 cm. long; swelling 1-2.5 cm. iad declination mostly 30°-60°. oo cc. washed in — epicotyls 2.5-4 cm. long; swelling 1-2 cm. long; Scitation 60°-9 b) Oxalic acid-derived CO . 50CCc.; epicotyls 4-7.5 cm. tall; no swelling, but diameter larger than checks; fetta tion 25°-35 : 8. 100 cc.; epicotyls 3-5. 5 cm. long; swelling 1-2. 5 cm. long; declination 60°—90°. g. 200 cc.; epicotyls 3-5 cm. long; swollen zone 1-1.5, with declination 75°—90°. c) Sodium formate-derived CO Io. 50cCc.; epicotyls 5-7 cm. long; no swelling, but declination 15°-40°. II. IOOCC.; ery 4.5-5.5 cm. long, with swelling 1.5-2.5 cm. long, and declination 60°—90 12. 200 CC.; ‘steels 3-5 cm. long; swollen zone 1-2 cm., with declination 70°90". A series of photographs will show the response to CO (oxalic acid-derived) of various concentrations (fig. 4). It is evident that the responses obtained in this experiment are due to the CO con- tained in the gases and not to impurities. When the data and figures on CO are compared with those on smoke from paper cigarettes, it is seen that the smoke is about 10 times as toxic as pure CO; 10 cc. of the smoke give responses similar to 100 cc. of CO, and 20 cc. of the smoke similar to 200 of CO. Since the smoke is approximately 15 per cent CO, it contains only about ;'y enough CO to determine its toxicity. This helps to substantiate the conclusion that the heavy hydrocarbons determine the toxic limit of paper and tobacco smoke, so far as the plant organ studied. is concerned. 1913] KNIGHT & CROCKER—TOXICITY OF SMOKE 361 Various amounts of nicotine (1-30 drops) were placed on filter papers and sealed in 1o-liter cans with cultures. Only the smaller amounts completely volatilized, but in none was any inhibition of growth notice- able. The test seedlings in culture cans of various sizes, bearing several grams of pulverized KCN, showed no inhibition of growth. In this connection it should be stated that HCN exists in such small quantities in tobacco smoke (o-6o mg. from 100 gm. of tobacco) that LEHMANN (18) does not take it into consideration as a toxic factor with the smoker. It is certainly much less to be considered in plants to which it is rather slightly toxic. a TC . 4.—Responses to CO: a, check; b, 50 cc. of CO in to liters; c, 100 cc. of CO in Io hth d, 200 cc. of CO in ro liters. The following table (p. 362) shows the nature of the responses caused by other constituents of tobacco and paper smoke and the concentrations necessary to produce them. In this table inhibition of growth corresponds to the sixth response of Netyusow, declination to the fifth, and horizontal nutation and swelling to the third. Only 4 of the 30 or more com- mon gases and vapors whose effect on this organ we have studied certainly produce “declination” or “horizontal nutation and swel- ling.”” They are ethylene, acetylene, propylene, and carbon monox- ide. This does not include the mixtures of gases (illuminating gas 362 : BOTANICAL GAZETTE [MAY and various smokes) in which the response is quite certainly due to one of these constituents. It also omits methane, for which it is not yet certain whether the response produced by the very high concentration given above is due to methane or to impurities. This uncertainty exists because methane derived by three different methods gave extremely great differences in magnitude of toxicity, though analyses showed the three sorts to contain approximately the same percentages of methane. At most, methane is very slightly toxic, if indeed further experiments do not prove it entirely harmless. PARTS PER MILLION OF ATMOSPHERE TO PRODUCE GAS USED fax ; - , nhibition o Seer orizontal nutation growth Declination and swelling Dok oi 5. es Ss fee 0.2 0.4 PREV ONON Soi eS SG ee aes 5 100.0 250.0 500.0 ne hs se 75.0 1000.0 1000.0 Carbon monoxide. ...........: 5000.0 5000.0 10,000, Biethane.........-...------- 60,000. 0? 200,000 . 0? 500,000. 0? feiss i oe None None Hydrogen sulphide........... 500.0 None None POR iain pk eek 3000.0 None None The nature of the response (triple response) of the seedling to paper and tobacco smoke shows that it must be caused by one of the four carbon-bearing gases mentioned above or by homologues of some of them. Before going into the probability as to which of these determine the effective limit of the smoke, let us consider the concentrations of other constituents in unwashed tobacco smoke and the chances that they may play some part, at least, in the inhibition of growth, in experiments such as reported in this paper or those performed by Mo iscu. According to LEHMANN (18) 100 gm. of tobacco when smoked in a pipe or as a cigar produces about 16 cc. of H,S. In experiment II (3) in which the smoke from 0.0375 gm. of cigar is placed in a 50-liter can, NELJUBOW’s third response appears. The H.S con- tent in this experiment, if it had not been washed out, would be I part in 8 million of atmosphere, or about 0.0002 sufficient to reduce growth. According to the same worker, 100 gm. of tobacco when thus smoked produces 0.935 mg. of NH;. In experiment II 1913] KNIGHT & CROCKER—TOXICITY OF SMOKE 363 (3), according to these figures, if the smoke had not been washed, ammonia would have been present in the proportion of ro parts per million of atmosphere, or in about 0.003 sufficient concentration to inhibit growth. Pyridine exists in very small quantities in tobacco smoke, certainly far below amounts that would inhibit growth in experiment II (3). Both the nature of the response of the seedling and the con- centration of the smoke necessary to produce it indicate that one of the four carbon-bearing gases mentioned above or homologues of some of them fix its toxic limit. We have shown that it cannot be carbon monoxide on account of insufficient quantities of that substance. In what percentages of the smoke must the others exist to determine its toxicity? Let us consider experiment III (2) of washed smoke of the loosely rolled paper cigarette, almost as toxic as any tested. In this case it required 10 cc. of the smoke in 10 liters to give NELJUBOw’s third response, or the response listed in the table above as “horizontal nutation and swelling.” Using the figures in the table above as the basis for calculation, ethylene must be present in 0.04 per cent, acetylene 50 per cent, and propyl- ene 100 per cent of the smoke, to determine its toxicity. In experi- ment III (2) under discussion, the heavy hydrocarbons were not in sufficient concentration to be detected by the gas analysis methods used, which should easily detect 0.2 per cent. If one of these three gases is responsible, it must be the ethylene. In short, the sweet pea seedling will give the triple response in concentra- tions of ethylene 0.001~-0.002 sufficient to be detected by gas analysis methods, while it will respond by reduced growth in con- centrations 0.0003 to 0.0005 sufficient to be thus detected. It is possible that in tobacco burned in the open, as is done when using it as an insecticide in greenhouses, the ammonia is produced in larger quantities as compared with the heavy hydro- carbons, and that ammonia much more nearly approaches the toxic limit. We have already shown that paper burned as a cigarette produces smoke 50 times as toxic as when burned as an open sheet. This means a great fall in the production of heavy hydrocarbons under conditions of high oxygen supply. There is probably also less ammonia produced when the aeration is better, for LEHMANN 364 BOTANICAL GAZETTE [MAY (18) found that in cotton cigarettes impregnated with nitrates much of the nitrate nitrogen was reduced to ammonia nitrogen. Such reductions likely occur to a much slighter degree under better conditions of aeration. Similar conditions may hold for hydrogen sulphide. V. General considerations In the destructive distillation gases from carbon compounds, whether we consider smoke or illuminating gas, the preponderant toxicity of the heavy hydrocarbons, especially ethylene, is very interesting. The present paper shows this relation to hold for the sweet pea epicotyl, while a former paper pointed out the same situation for the carnation flower. Mr. E. M. Harvey of this laboratory has shown that the ethylene in illuminating gas deter- mines the toxic limit of that mixture to the roots of Vicia Faba, though in this case the magnitude of toxicity is much less than in the cases of the two plant organs mentioned above. In the light of the facts set forth in this paper, it becomes probable that the extreme toxicity of smoke for seedlings observed by MOLIscH (22) can be attributed to the heavy hydrocarbons. It is as yet un- answered whether the nocuous character of smoke to various micro- organisms, and to the organs of mature angiosperms as observed by this writer, is due to the same constituent. Whatever be the case, it is clear that some plants are quite resistant to the destruc- tive distillation gases of carbon compounds, as Moriscu states and as RicHARDS and MacpouGat (31) have found. To what degree the resistance is due to protective structure or permeability char- acters and to what degree to peculiarities of the plasma cannot be stated. It is probable that production of the toxic materials from carbon compounds begins considerably before the lower tempera- ture limit set for destructive distillation is reached. In soils it was found in this laboratory that heating but slightly above go” C. for an hour liberated substances that produced the “triple response” in the pea epicotyl. Mr. Harvey is now making a study of the gases liberated from soils when heated at various temperatures. It is evident that contact of hot steam pipes with soil in greenhouses 1913] KNIGHT & CROCKER—TOXICITY OF SMOKE 365 may produce gases very toxic to plants. Whether they are likely to reach sufficient concentration to do injury is not determined. Injuries from coal smoke are generally attributed to tars and oxides of sulphur (3, 4, 7, 40,), while reduced carbon-bearing gases have never been considered as a factor. According to HEMPEL (14, p. 257), these gases, especially the heavy hydrocarbons, exist in such small quantities, if at all, even when the oxygen supply is very little more than enough to produce complete oxidation, that they cannot be detected by gas analysis methods. This does not mean that they can be neglected as a source of injury to vegetation, for, as we have shown, growth rate is reduced in the pea epicotyl in 0.0003—0.0005, the least concentration of ethylene detectable by gas analysis methods. In short, while the gas analysis methods are quite adequate for guarding against considerable energy loss due to incomplete combustion of heavy hydrocarbons in furnaces, the only way to make sure that they are not in sufficient concen- tration to do injury to vegetation is to use a more delicate test, such as the pea epicotyl. One factor that favors the effectiveness of the oxides of sulphur as plant poisons in the open as against heavy hydrocarbons is their great solubility in the plant cell, which would lead to their accumu- lation even under great variation in the atmospheric concentration, whereas the heavy hydrocarbons will accumulate to a far less degree, and variations in concentration greatly reduce their injurious effects. It is probable that smoke from the beehive coke oven is much richer in heavy hydrocarbons than furnace smoke, especially in the early firing (2). Part of the destruction of vegetation about these may be due to the carbon-bearing gases, though here, as in furnace smoke, there is an abundance of sulphur dioxide and tars. The economic loss through injury to vegetation is probably rather slight, because of the nature of the region in which this industry is carried on. It certainly is inconsiderable beside the $44,000,000 worth of products this wasteful method of coking is pouring into the atmosphere annually in the United States alone (19). Artificial illuminating gas is a source of great economic loss through injury to plants. A large number of cases of injury to greenhouse stock in different parts of the country have been called — 366 BOTANICAL GAZETTE [MAY to our attention. As we have already pointed out (6), these losses generally occur during cold periods in winter. This insures a frozen crust, promoting lateral diffusion of the gas from the faulty mains; it also prevents ventilation of the greenhouses. So far as evidence for the constituents that produce the injury goes, it suggests the heavy hydrocarbons, though it is not by any means proved that these are responsible for all such injuries. A source of greater loss from illuminating gas is injury to shade trees. This injury is through the roots, in contrast to the injury in greenhouses. We are unable to state as yet what constituents produce the injury, though Mr. Harvey’s work in this laboratory indicates that ethylene determines the toxic limit of the gas for the roots of Vicia Faba. Even so, it is possible that the less volatile materials of the gas accumulating in the soil may really be the source of injury, the power of accumulation overbalancing the higher toxicity. The determination of the constituents producing the injury and the tenacity with which they adhere to the soil are of great importance. They determine how soon and under what conditions replacing of the dead trees by new ones can be carried out. Mr. HARVEY is now attempting to answer these questions. The odor-producing substances of illuminating gas are retained in the soil with great tenacity, but so far as the pea epicoty] is concerned, these substances are innocuous, at least in concentrations easily detected by smell. Natural gases are generally low in heavy hydrocarbons; in fact, those of the Appalachian system bear none so far as chemical tests indicate (1); they consist mainly of methane and ethane. This gas should be very low in its toxicity to plants. The Baku natural gas is said (30) to contain some olefines. The few facts established in this field suggest the need of ration- alizing various practices in vogue and summarily abolishing others; for instance, the practice of burning tobacco stems in greenhouses for killing insects. This is a matter of differential poisoning, apply- ing a poison that will kill the insect without injuring the plants. The processes volatilize nicotine and set free carbon monoxide, ethylene, and other gases. So far as we know, it is not certain which is the insecticide. If it is nicotine, why not volatilize nico- tine from an extract and avoid the deadly plant poison ethylene ? AetOLS] KNIGHT & CROCKER—TOXICITY OF SMOKE 367 If it is carbon monoxide, why not generate it chemically and thereby avoid ethylene? Again, it is a rather common practice to have the heating furnace in more or less open connection with the greenhouses. If one recognizes the probability of the dry distilla- tion gases escaping from a furnace, along with the extreme toxicity of ethylene, he can see the need of abolishing this practice. So far as known, the etiolated epicotyl of the sweet pea is the most sensitive plant organ to ethylene. As has been stated, it is inhibited in growth by 1 part in 10,000,000 of atmosphere. The open flower of the carnation is only a little less sensitive. In our original measurements (6), which were made on plants that had been bearing flowers for several months, 1 part in 2,000,000 of atmosphere “put the open flower to sleep” in 12 hours. Some later measure- ments with plants soon after they had begun to flower showed that I part in 3,000,000 of atmosphere caused the same response. While the open flowers on these younger plants were much more sensitive to ethylene, the buds proved much more resistant than the buds of plants longer in bearing. If, in the few cases tested, two such sensitive plant organs have been found, it is probable that many more exist. So far as we know, there is in nature no special absorbent for ethylene, also no cycle for the gas, as there is for carbon dioxide and oxygen. Even if both existed, one doubts if 1 part in 10,000,000 would lead to a with- drawal. Processes of civilization are continually adding to the ethylene in the atmosphere, as burning of all carbohydrates, burn- ing of coal (?), escaping of artificial illuminating gas, producing of gas in the beehive method of coking, escaping of certain sorts of natural gas, and probably other processes. Having no estimate of the total additions from these sources, one cannot calculate whether accumulation in the atmosphere up to a danger point is likely to occur. The etiolated epicotyl of the sweet pea is a very delicate test for the heavy hydrocarbons, especially ethylene. One of the papers to be published later will show that under proper application it is also a very reliable test for this group of substances. It could be used to determine the presence or absence of this group of gases in coal smoke, gas from coal (28), and natural gas, where gas 368 BOTANICAL GAZETTE [MAY analysis methods are inadequate. To the experimenter in plant physiology it furnishes an excellent means of making sure that the laboratory air is sufficiently ‘‘pure” not to interfere with plant response, while to the practical greenhouse man. it furnishes a means of determining the probability of injury from illuminating gas or other mixtures bearing ethylene. Summary 1. The smoke from tobacco cigars and cigarettes which has been thoroughly washed in 15 per cent H,SO, and 4o per cent NaOH is very toxic to the etiolated epicotyl of the sweet pea. In the case of cigar smoke thus treated, 1000 parts per million of atmosphere give a triple response: reduction of rate of elongation, swelling, and diageotropism of the portion growing in the impurity; 5000 parts per million of atmosphere completely stop elongation and produce a swollen knob, while the epicotyl remains vertical; still higher concentrations kill the epicotyl before any form change occurs. 2. On the basis of dry weight burned, the washed smoke from cellulose paper cigarettes is even more toxic. The characters of the responses produced are identical with those produced by smoke from tobacco cigars and cigarettes. 3. When smoke from equal amounts of cellulose paper, smoked as a cigarette on one hand, and burned as an open sheet on the other, are compared, it is found that the former is 50 times as toxic as the latter. Higher oxygen supply during burning greatly reduces the toxicity. A large part of the toxic gases are undoubtedly oxidized to CO, and H,0. 4. In the cigarette smoke of cellulose paper the following gases are present: carbon dioxide, carbon monoxide, acetylene, ethylene, methane, and some higher homologues of the last three. Washing out the carbon dioxide does not reduce the toxicity of the smoke, nor will carbon dioxide produce the type of response produced by the smoke. Carbon monoxide, acetylene, ethylene, propylene, and perhaps methane produce the same type of response as smoke. Carbon monoxide is in 0.015 sufficient concentration to determine the effect of smoke. It is not certain that methane is toxic at all; 1913] KNIGHT & CROCKER—TOXICITY OF SMOKE 369 if so, it is not in o.o00o1 sufficient concentration to produce the response. The other three gases mentioned are not present in the smoke in sufficient quantities to be detected by ordinary gas analysis methods. Considering the magnitude of toxicity of acetylene and propylene, it is impossible that they play any part in the toxicity - of paper smoke. The great toxicity of ethylene makes it probable that it determines the toxic limit. One part of ethylene in 10,000,- ooo of atmosphere inhibits elongation of the epicotyl, 4 parts in 10,000,000 produce the triple response. The toxicity of paper smoke is greatly reduced by washing with bromine, which is further evidence that ethylene or some other heavy hydrocarbon is the effective gas. 5. In addition to these gases, tobacco smoke bears hydrogen sulphide, ammonia, nicotine, hydrocyanic acid, and pyridine. None of these produces the type of response in the seedling caused by the smoke, and they exist in the smoke in concentrations far below that necessary to determine the toxic limit. The facts stated in this paper, along with the work of Motitscu and others, show the hazard of using tobacco smoke as an insecticide for greenhouses. 6. The etiolated epicotyl of the sweet pea is a very delicate test for the heavy hydrocarbons (ethylene), exceeding many fold the delicacy of any chemical test. University oF CHICAGO LITERATURE CITED “3. ALtEn, I: C., and Burret, G. A., Liquefied products from natural gas; their properties and uses. U.S. Bur. of Mines (technical paper) 1031-28, Igi2 . 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B., Chemische und toxikologische Studien iiber Tabak, Tabakrauch, und das Tabakrauchen. Archiv. fiir Hygiene 68: 319-420. 1908-1909. 19. MOLDENKE, RicHarD, The coke industry of the United States as related to the foundry. U.S. Bur. of Mines Bull. 3:1-32. 1900. 20. Mouiscu, H., Uber Heliotropismus im oo .. ae ag Kais. Akad. Wiss. (Wien) Math. Nat. Kl. 111:141-148. 1 21. ———,, Leuchtende Pflanzen. viii+1908 (citation . ae Jena: Guay. Fischer. 1912. 22. ———, Uber den Einfluss des Tabakrauches auf die dene — I. Sitzungber. Kais Akad. Wiss. (Wien) Math. Nat. KI. 120: 3-30. ; , Uber den — des Tabakrauches auf die Pflanze. “Tel Il. Op. cit. 120:813-838. 19 24. , Die Pflanze ani Tabakrauch. Umschau 15:259-264. 1gII. 25. Necscnow, D., Uber die horizontale Nutation der Stengel von Pisum sati- vum und einiger anderen Pflanzen. Beih. Bot. Centralbl. 10: 128-139. 1901. 1913] KNIGHT & CROCKER—TOXICITY OF SMOKE 371 , Geotropismus in der Laboratoriumsluft. Ber. Deutsch. Bot. Gesells. 29:97-112. 1911. . NEmec, B., Uber die Einwirkung des Chloralhydrates auf die Zell- und Kernteilung. Jahrb. Wiss. Bot. 39:645-730. 1903. Porter, H. C., and Ovirz, F. K., The escape of gas from coal. U.S. Bur. of Mines (technical paper) 2:1-14. 1911 5 pg NISCHNIKOW, D., Zur oe der Asparaginbildung. Ber. Deutsch. Bot. Gesells. 22: 35-43. - REDWoop, SIR Bore "Natural gas in Encyclopaedia Britannica 19: 274. Igto ‘ yee H. M., and Macpovueat, D. T., The influence of carbon mo- noxide and other gases upon plants. Bull. Torr. Bot. Club 31: 57~66. 1 32. RicuTER, O., Pflanzenwachstum und Laboratoriumsluft. Ber. NIE Bot. Gesells. 21: 180-194. 1903. 33. ———, Uber den Einfluss verunreinigter Luft auf Heliotropismus und ~ we $ Géstnoplinion: Siztungsber. Kais. Akad. Wiss. (Wien) Math. Nat. KI. T1I5: 265-352. 1906 , Die horizontale Nutation. Op. cit. 119: 1052-1084. IgIo. , und Grare, V., Uber den Einfluss der Narkotika auf die Anatomie und die chemische Zusammensetzung von Keimlingen. Verh. Gesells. Deutsch. Narutf. und Artze 80:189. 1908 . Ricuter, O., Uber Ds aaa in der Atmosphiire von Narkotika. Lotos 56: 106-107. 1908. , Neue Untersuchungen i ag im Pflanzenreiche. Mitt. Natcewing Ver. Univ. Wien 9:14. ber Antocyanbildung in ie eae a von duseren Faktoren. Med. Klinik. 3: 1015-1020 190 - Rover, F., Uber die Nutationen oad Wacltukeclnten der Keim- ollaneen pee ee Kais. Akad. Wiss (Wien) Math. Nat. Kl. 89:393- 422. 188 . Ruston, A. C., and Crowruer, C., Impurities in the atmosphere of towns and their effects upon vegetation. Report Brit. Ass. Adv. Sci. 577-578. IQIO, SEARLE, J. M., Coal smoke and its practical — Report Engineer’s Soc. Pittabureh: pp. 18-19 (meeting of June 18, 19 . SINGER, M., Uber den Einfluss der Laberatorinnaiate auf das Wachstum der Kartofflsprosse. Ber. Deutsch. Bot. Gesells. 21:175-180. 1 1903. . Wiesner, J., Die undulierende Nutation der Internodien. Sitzungsber. Kais. Akad! Wiss. (Wien) Math. Nat. Kl. 77:15~54. 1878. . Witcox, E. M., Injurious effects of illuminating gas upon greenhouse plants. Ann. Report Neb. State Hort. Soc. pp. 278-285. 191T. WESTERN PLANT STUDIES. I AVEN NELSON AND J. FRANCIS MACBRIDE [The last four numbers of “Contributions from the Rocky Mountain Herbarium” (IX—XII) were based largely upon the collections made by Mr. J. Francis MACBRIDE in toro and by MAcBRIDE and myself in 1911. During the season of 1912, the field work was continued by MaAcsrivE assisted during a part of the time by Mr. Dorman Bennirtt and by the writer. The territory covered was a small part of southwestern Idaho and certain parts of Nevada in and adjacent to the Humboldt National Forest. Our work in Nevada was greatly facilitated by the kindly assistance of the Forest Service, and we wish to acknowledge gratefully the many courtesies extended by Supervisor C. SIDNEY TREMEWAN and his assistants and foresters. The types, the numbers of which are given, were all collected by Netson and MacsrinE and are deposited in the Rocky Mountain Herbarium. In working up the collections of 1912, Mr. MAcBRIDE has been associated with me, and the paper presented herewith is the result of this collaboration. This and other papers that we may publish jointly will be under the above title; while those for which I individually assume responsibility will be con- tinued as “Contributions, etc.’”,—AVEN NELSON. | Calochortus bruneaunis, n. sp.—Stems striate, minutely sca- brous in lines, especially near the base, 2-4 dm. high, more or less tortuous: bulb narrowly oblong, covered with brown, dead scales, as is also the base of the stem: leaves several (4-6); the radical leaf nearly or quite equaling the plant; the cauline involute, expanded and scarious-margined at the sheathing base, 4—10 cm. long: flowers 1-3, axillary in the upper leaves: sepals rather broadly lanceolate, 2-3 cm. long, tapering gradually to a slender tip, colored like the petals within, green without but with a broad white scarious margin to above the middle: petals broadly obovate-cuneate, rather abruptly rounded above into a blunt point, longer than the sepals; body-color white, delicately streaked with green, with a green band from apex to the narrow yellow claw, just above which is a small purple inverted y-shaped or lunate blotch: petal wholly glabrous, even the small oblong gland at the summit of the short claw scarcely pubescent: anthers obtuse, purple, 6-8 mm. long, about equaling the filaments: capsule narrowly oblong. Botanical Gazette, vol. 55] [372 1913] NELSON & MACBRIDE—WESTERN PLANTS 373 This makes the third species in the green-banded group, the others being C. cyaneus A. Nels. and C. macrocarpus Dougl. The latter is the nearer relative to the species now proposed. C. bruneaunis is easily distinguished by the rather tortuous stems, the different color and marking of the flowers, and the glabrous petal faces. 0. 1881, found in chipped lava, high on the canyon sides of the “Hot Hole” of the East Bruneau, Owyhee County, Idaho, is the type. Clematis aurea, n. sp.—Glaucous, climbing freely by the petiolules: stems glabrous, striate: leaflets broadly to narrowly lanceolate, petiolate, pale green, irregularly incisely dentate, acuminate-cuspidate, midvein prominent beneath: bud green, drooping, erect in anthesis, the four sepals then golden yellow, 4-5 cm. long, oblong, obtuse, cuspidate, rather thick, prominently nerved, glabrous except for an incurved villous margin: the pubescent filaments dilated, 8-1omm. long, all antheriferous; anthers linear, about 5mm. long, obtuse, minutely cuspidate: achenes pubescent, the persistent black styles filiform, only moder- ately white plumose throughout, 4-5 cm. long. Collected in July 1909, at Challis, Custer County, Idaho. It was locally plentiful, clambering over rosebushes, etc., along a stream, and attracted attention by its unusual color and beauty. It is a member of the section ViornA, though with sepals scarcely leathery. In aspect the plant more nearly resembles some members of the section ATRAGENE. Delphinium megacarpum, n. sp.—Much resembling D. Andersonii Gray, having a similar fascicle of Jong thickened woody roots and a strict mostly simple few-leaved stem: basal leaves petioled, from puberulent to nearly glabrous, suborbicular in outline, cuneately divided or parted, the lobes cleft into linear divisions; the stem-leaves rather remote, gradually reduced in size and num- _ ber of lobes, puberulent or more usually sparsely hirsute-ciliate, the bracts and base of petioles conspicuously so: stems rather stout, 2-5 dm. high, at first cinereous-puberulent to the base, becoming glabrate below in age: inflorescence narrow, racemose and usually with one or more slender erect floriferous branchlets from the upper- most axils: flowers dark blue: calyx softly hirsute, spur longer than the sepals and: these exceeding the petals: carpels puberulent even at maturity, linear-oblong, 20-25 mm. long, erect and parallel, 374 BOTANICAL GAZETTE [MAY only the tips divaricate, reticulately veined: seed-body large, dark, narrowly winged on the margins and with a depressed summit. This species has passed for D. Andersonii and is a close relative of it. The typical form of that seems to be confined to western Nevada and adjacent California. Taking those characters on which. Dr. Gray laid stress, namely, “very glabrous’’; “follicles oval or oblong, not over half an inch in length”; “seed body small and broadly winged,” as diagnostic, one is almost forced to separate this pubescent long-carpelled form. The segregate occurs in interior northern Nevada, Idaho, and adjacent Oregon. No. 1779, House Creek, Idaho, June 29, 1912, is the type number. ARABIS MENziest lata, n. var.—Closely allied to the species, but the pods broader (as much as 6mm.), 2.5-4.5 cm. long, usually about twice as long as the pedicels; style nearly wanting. As shown in Proc. Biol. Soc. Wash. 17:91 and 18:187, the PHOENICAULIS section of Parrya is less aberrant in Arabis than in Parrya. Typical Arabis (Parrya) Menziesii will not run to Parrya by any of the keys to the cruciferous genera, but does run to Arabis by most, if not all, of such keys. The variety here described is probably the P. Menziesii of Bot. King Rep. 14, in part. Fully mature material is our no. 1838, from lava cliff pockets, House Creek, Idaho, June 30, 1912. ARABIS PEDICELLATA A. Nels., Proc. Biol. Soc. Wash. 17:91 is Parrya Menziesii lanuginosa Wats., and may best become ARABIS MeENZztIEst lanuginosa. Horkelia beneolens, n. sp.—Caudex simple or branched, more or less fleshy or becoming woody, thick because of the dense coat of dead brown petioles, the flaccid sordid herbage clammy with a short glandular pubescence: stems few-several from each crown, sparingly leafy, 7-15 cm. long including the rather open inflores- cence: leaves several from each crown, mostly oblong, with 5-9 pinnae, on slender petioles: pinnae 7-15 mm. long, alternate or irregularly opposite, oblong, flabelliform or suborbicular, more or , less deeply palmately parted into oblong obtuse or acutish lobes; stem-leaves short, with fewer pinnae (3~5) and short petioles (or subsessile); stipules ovate-oblong: flowers few-many on slender pedicels in an open cyme: calyx rotate, with flat pentagonal hypan- thium with a marginal flange giving a sunken or inverted salver- form effect (as in the base of the calyx of some species of Physalis in fruit); lobes ovate, acute, about 3 mm. long, fully twice as long 1913] NELSON & MACBRIDE—WESTERN PLANTS 375 as the small linear-oblong bractlets: petals white, shorter than the lobes of the calyx, the small linear-lanceolate blade scarcely longer than the slender claw: stamens 5; the brown anthers subspherical, their cells opening lengthwise: pistils 3-5, sometimes all maturing: achenes large (2 mm. long), flattened, ovoid, with the inner edge nearly straight, noticeably longitudinally ridged on the surface. This plant has the foliage of some of the sections of Horkelia, the numerical plan of certain species of Ivesia, while the calyx characters come nearest to Comarella. Unfortunately this cannot get into that genus since init the petals are red and the pistils only two. On the whole the plant ‘here described prob- ably comes nearest to Horkelia Baileyi (Wats.) Rydb. The specific name chosen refers to the delightful fragrance emitted by the plant. It does not seem possible to maintain these three genera in view of the increasing number of species that show characteristics that overlap the generi¢ bounds. In fact, what character, except the open space between pistil-bearing _ receptacle and the margin of the hypanthial disk, separates any of them con- stantly from Potentilla? Agreeing in this one character and overlapping as to other characters, it is in the interest of simplicity to let Horkelia include them all No. 1708, Castle Ford, on the Salmon, in Idaho, is the type. It was found hanging in wet crevices on the vertical faces of basaltic cliffs, June 25, 112. POTENTILLA GLOMERATA dichroa, n. comb.—Potentilla dichroa Rydb. N. A. Fl. 22:319. 1908.- This is distinguished from the species only by the denser tomentum on the under side of the leaves and the grayer color of the plant as a whole. Astragalus owyheensis, n. sp.—Spreading, prostrate, many- stemmed perennial, tufted at base, minutely and sparsely strigillose, the slender wiry stems, including the open racemes, 2-6 dm. long: ‘Stipules triangular, the lower about 3mm. long and scarious, upward becoming smaller and green: leaves 6-10 cm. long, rather irregularly pinnate; the leaflets (5~13) remote, shorter than the internodes, linear: the very open axillary racemes exceeding the leaves: the slender pedicels 3-6 mm. long: calyx finely strigillose with intermingled black hairs, the subulate teeth about one-third as long: flowers 8-10 mm. long, white; standard 5 mm. wide, rather deeply emarginate, the edges strongly recurved, forming two crests at the edge near the middle of the blade: wings not emarginate, narrowly obovate, the edges incurved: keel shorter, with a broad 376 BOTANICAL GAZETTE [MAY rounded incurved apex: pod oblong-linear, pubescent like the plant, shortly acute, 10-18 mm. long, straight or slightly curved, usually recurved but sometimes ascending, one-celled, the dorsal suture being but slightly intruded: seeds few (about 5). Perhaps this finds its nearest relatives in A. atratus Wats. and A. obscurus ats. No. 1887, collected July 2, 1912, above the “Hot Hole” of the East Bruneau, Owyhee Co., Idaho, is the type. It was quite inconspicuous because of its color and its fasta of creeping among the short grasses of the sagebrush plains. GERANIUM CAESPITOSUM gracile, n. comb.—G. gracile Engelm. in Gray Pl. Fendl. 27. 1849; G. atropurpureum Heller, Bull. Torr. Bot. Club 25:195. 1898; G. furcatum Hanks, N. A. Fl. 25:16. 1907. Specimens of G. ‘caespitosum when they show a tendency to become glan- dular pubescent on the pedicels have been considered as G. gracile (G. atropur- pureum), and if this glandulosity extends to the stem they are G. furcatum. A series of specimens can be so arranged as to show all degrees of glandulosity to the complete lack of it. The proposed variety, therefore, rests primarily upon the slenderer and more erect stems, the narrower petals, and usually a trace of glandulosity. Where the glandulosity becomes marked throughout, it merges into G. Parryi (Engelm.) Heller. It is somewhat singular that there should be any misunderstanding in regard to Geranium caespitosum James. Admitting that the original printing of the name did not publish the species, Dr. Gray’s diagnosis in Pl. Fendl. 25 and Dr. TRELEASE’s in Bost. Soc. Nat. Hist. 4:72 fixed the plant to which this name must apply. Specimens answering to this description are not rare in the herbaria and are always non-glandular and with the pubescence of the stem (whether sparse or abundant) more or less retrose. The plant is always cespitose, growing in the form of a turf or mat from which short assurgent stems arise. The new characterization in the N. A. Fl. 25:15 would seem to be without warrant, and at best that description presents merely one of the variants of G. Fremontii Torr. Specimens wholly typical of G. caespitosum are BAKER 448, Colorado; Baker, EARLE, and Tracy 407, Colorado; 1155 from Colorado, distrib. by the New York Bot. Gard. as one of the type nos. of G. Cowenii Rydb.; BuFFUM, Wyoming; NELSON 8591, Wyoming; METCALF 194, New Mexico; MACDOUGAL 118, Arizona. Besides G. Cowenii, G. marginale Rydb. must undoubtedly be referred to G. caespitosum as here understood. GENTIANA AFFINIS major, n. var.—Leaves uniformly narrower: calyx lobes oblong-lanceolate, nearly equal and all approximately 1913] NELSON & MACBRIDE—WESTERN PLANTS 377 equaling the tube: corolla broadly funnelform, larger, diameter at the top more than 2 cm.; the plaits purple, alternating with green bands extending downward from the lobes, the sinuses short. This would be a good species if all st leading to the above characters were not present in a collection of nis. Collected at Mountain City, Elko Co., Nevada, August 9, 1912, no. eee _?Nemophila explicata, n. sp.—Branching from the base; the branches sometimes sparingly branched, 7-15 cm. long, spreading or weakly erect, glabrate, the scattering hairs short and refracted: leaves obovate or orbicular in outline, cuneately tapering into a margined petiole one-fourth to one-half as long as the blade, crenately 3—-5-lobed, 10-20 mm. long, sparsely strigulose with more or less appressed hairs: pedicels 7-14 mm. long, at length more or less reflexed or even refracted: flowers small, not white; calyx appressed strigulose, in fruit 2 mm. or scarcely more long; its tube short; its lobes ovate, sparsely short ciliate on the margins, its ap- pendages small, oblong, as long as the tube: corolla small, barely exceeding the calyx, tubular-campanulate, its oval lobesal most as long as the tube, the plicae or appendages wholly wanting: style short, divided at apex only: capsule 3-4 mm. long, more or less appressed cinereous-strigulose: seeds 4, large, 3 mm. long, irregular quadrants, slightly roughened, pale yellow with numerous small brownish dots or obscurely pitted; the membranous cellular car- uncle caplike. Secured at Jarbidge, in the canyon of the East Bruneau River, among shale- lava, growing with N. breviflora Gray. Only one other of the described species seems to be devoid of appendages in the corolla tube. No. 2229, July 7 7, 1912, is the type Phacelia foliosepala, n. sp.—Slender annual, 7-12 cm. high, hirsute-pubescent and glandular, trichotomously — branched (candelabra-like) twice or thrice, the branches usually simple, floriferous to near their bases: leaves few, scattering, I-1.5 cm. long, oblanceolate, obtuse, tapering below to a short margined petiole: inflorescence racemose, rather open in fruit (flowers unknown): pedicels about 2 mm. long: calyx lobes foliar, unequal, resembling the leaves, 10-15 mm. long, more than twice as long as 378 BOTANICAL GAZETTE [MAY the capsule: capsule oval: seeds 12, irregularly ellipsoidal, beauti- fully alveolate, seal brown when mature. Possibly this may best be referred to the section Euroca Gray, but even in this section there seems to be no species nearer to it than P. linearis (Pursh) Holz. That, however, is a very different plant in its mode of branching, in its different and glandless pubescence, and probably in all of its floral parts as it evidently is in its calyx. It is interesting that this little annual possessed (according to the field notes) a “‘strong vile odor, something fierce,’ reminding one of those perennials like Goopp1no’s P. foetida that proclaim their identity while they are still a long way off. The type is no. 2232, Gold Creek, Nevada, July 27, 1912; moist sunny flat. Oreocarya cilio-hirsuta, n. sp.—Biennial or, apparently, some- times perennial, from a slender taproot more or less branched at summit; the branches of the caudex or crown short and clothed with the inordinately crowded linear leaf-bases: stems several- many, very slender, somewhat angled, greenish but thinly hirsute and with an admixture of long white stiff ciliate-appearing hairs, 15-30 cm. long and floriferous in the axils for half their length: crown leaves very numerous, 2~4 cm. long, linear, the upper part more or less spatulate and not more than half as long as the slender petiolar portion; cauline shorter, mostly broadly linear; all with pubescence similar to that of the stems: the rather small axillary thyrsoid clusters 10-15, crowded above, more open below and usually surpassed by the foliar bracts: inflorescence moderately hirsute-hispid: calyx lobes linear-lanceolate, 6-8 mm. long in fruit: corolla tube barely as long as the calyx, its lobes suborbicular, half as long as the tube: nutlets ovate as to the body but narrowed and subacute at apex, bordered by a filiform wing-margin, sparsely but sharply muriculate on the back, even more minutely on the ventral side, not at all rugulose; scar linear, nearly as long as the nutlet, slightly enlarged at the base but not forked. The type is no. 1799, from Minidoka, Idaho, June 23, 1912, where it was growing in the loose sagebrush soil. MACBRIDE’s no. 93 from New Plymouth, May 21, 1910, and his no. 875, from Sand Hollow, June 2, ror1, were dis- tributed as O. affinis and O. affinis perennis respectively. Neither of these accord very closely with the species to which they were referred, and although not identical with the species here proposed, they will probably have to be considered a part of it rather than of O. affinis. 1913] NELSON & MACBRIDE~WESTERN PLANTS 379 CASTILLEJA MINIATA Dougl.—Special effort was made to secure as full a series as possible in this genus in order to see something of the degree of variability within specific lines. No species shows how great this variability is better than C. miniata. Incidentally it may be remarked that the making of synonyms is not always due to the variability in the specimens representing a species, but quite as often to errors in the original descriptions which authors continue to copy and with which we constantly compare new material. Another source of error is found in the habit, more or less prevalent, of naming up material by comparison alone. A has a specimen slightly aberrant; B names his by comparison with A’s, and lets it pass though evidently somewhat different; C, having B’s plant, names his material accordingly, and so on. Look through any well filled species cover and see these facts illustrated. In the original description of C. miniata the galea is said to exceed the corolla tube. On the assumption that this was so for the species (it probably was on the type sheet) some segregates have been made by various authors that had better not have been made. C. miniata material measured by this yardstick contains few (if any) specimens that are typical. Dr. RyDBERG, for example, in working all the material for his Flora of Montana had but one number (RyDBERG and Bessey 4965, Wolf Creek, 1897). Unfortunately, too, other sheets of even this same number (4965) show only corollas in which the galea is shorter than the tube. The character is therefore more or less unreliable in this species, and hence probably in others. : Another character in Castilleja which is often misinterpreted is the root system. Collectors almost always pull the stems loose from the root or caudex. Being usually numerous in the clumps they are decumbent at base, and more or less rooted at the lower nodes. This often gives them the appearance of having been detached from a running rootstock when such was not the case. Of course it is generally known that the color of the bracts varies, and this gives the plants a very different look even when the color of calyx and corolla remains (as it should) fairly constant. These observations were induced by the necessity of distributing several of our numbers as C. miniata in spite of the fact that they refuse to accord fully 380 BOTANICAL GAZETTE [MAY with the hypothetical type. For example, our nos. 2131 and 2132, growing together in “placer wash,” agree in having a large intricately branched root, from the crown of which the stems spring. Both have corollas with the galea yellowish-green, scarcely as long as the tube, but our field notes read as follows: “5031, bracts most remarkably bright red; 2132, bracts a splendid golden yellow with orange tips.” No one studying these two critically can fail to decide they are the same species, and can scarcely fail to refer them to C. miniata. Castilleja Bennittii, n. sp—vVery short-lived perennial, sparsely hirsute throughout with a short dense cinereous subscabrous indument underneath: stems few, simple or often branched, 2-3 dm. high: leaves linear, entire or irregularly lobed, the lobes narrower than the blade: inflorescence dense, becoming more open and slender in age, old rose in color: bracts three-cleft, the lobes blunt, the middle the largest: calyx 15-20 mm. long, the subequal clefts only about 5mm. deep, these divisions shallow-lobed, the short rounded lobes terminating the prominent ciliate calyx nerves: corolla slightly, sometimes scarcely, exserted, 15-22 mm. long; the galea about half as long as the tube, the short rounded teeth hardly differentiated in the strongly nerved saccate lower lip. There seems to be no near relative to which to ally this species, unique in its color and floral parts. It was pronounced new in 1or11 on the strength of specimens submitted by DorMAN BENNITT of Twin Falls. It is a pleasure to dedicate it to its discoverer, who accompanied the.collectors on part of the 1912 trip and assiduously assisted in the field work. The type is no. 1714 secured on the sagebrush plains of Shoshone and Twin Falls, June 24, 1912. CASTILLEJA RHEXIFOLIA pubens, n. var.—The branches of the caudex and the stem-bases scaly: stems numerous (usually several of them short and sterile), with a villous crisped pubescence quite to their bases: lower leaves also with a similar, though shorter pubescence. No. 2023, on stony brush slopes, from Jarbidge, Nevada, July 11, 1912, is taken as the type. Castilleja curticalix, n. sp—Plants harsh to the touch, often decidedly so, in rather small clumps, from short-lived perennial roots: stems few-many, 2-4 dm. high, simple or nearly so, softly cinereous-hirsute near the base, becoming glabrate upward: leaves 1913] NELSON & MACBRIDE—WESTERN PLANTS 381 numerous, scarcely smaller above, often rather closely ascending, scabrous on both sides, sometimes ciliate on the margins, linear to narrowly lanceolate, 2-6 cm. long, usually entire, but not rarely with one pair of widely divaricate lobes: bracts resembling the leaves: the moderately crowded inflorescence at length rather open, predominating color yellow or greenish-yellow, but often flushed with red: calyx 1.5 cm. long, scarcely exceeding the corolla tube, subequally cleft above and below, the primary divisions cleft at apex into long acute teeth: corolla 2-2.5 cm. long, galea 7-10 mm. long, the lower lip scarcely saccate, with very short teeth, the outer the longer. Apparently the nearest allies of the proposed species are C. fasciculata A, Nels. and C. lutescens (Greenm.) Rydb. It differs from both in the very short calyx, also from the former in the harsh pubescence (in which it resembles C. lutescens), and from the latter in the narrower leaves. No. 2099 from Gold Creek, Nevada, July 24, 1912, is taken as the type. No. 2098 from the same locality and 1983 from Jarbidge, July 8, are both fairly representative. It occurs mostly on grassy slopes, CASTILLEJA FASCICULATA inverta, n. var.—Much resembling the species, but pubescence merely a fine puberulence: calyx exceed- ing the corolla, more deeply cleft above than below, its lobes short- bifid: galea and lip subequal. Practically all the perennial species formerly referred to Orthocarpus have been transferred to Castilleja, even when the corolla lips are subequal. This seems advisable, the more so in the present instance, because of its evident affinity with C. fasciculata A. Nels. In the subequal lips of the corolla, which is surpassed by the calyx, the proposed variety is strongly differentiated, and if subsequent collections show the characters given above to be constant it will become C. inverta. Secured at Rattlesnake Springs, Idaho, on hard gravelly soil among the sagebrush, no. 1915, July 4, 1912. : Pentstemon rex, n. sp.—Having the pubescence, herbage, and aspect of P. perpulcher A. Nels., Bor. GAz. 523273. 1911.—Corolla bright blue, about 3.5 cm. long, rather abruptly ampliate above the tube proper, wholly glabrous without and within as are also the anthers: sterile filament slightly dilated, glabrous or sparsely hispid- pubescent with short unequal hairs: anther cells dehiscent from the base upward for about three-fourths their length, leaving a closed saccate apical portion. 382 BOTANICAL GAZETTE [MAY This could be referred to P. perpulcher were it not for the strong contrast between its rather small flowers and the large showy ones of this. Then the dehiscence character is unique in the P. glaber group. Some of the red-flowered species of Penistemon, recently erected into a separate genus by Dr. GREENE, have anthers in which the upper portion of the cells remain closed and saccate, but none are known to the writers in the other sections of the genus. The SACCANTHERA section, of course, has anthers in which the base of the cell is the part that remains closed. ee ae ae four numbers are all representative, but the first is named as the type: no 9, Jarbidge, Nevada, July 9, 1912; no. 977, MACBRIDE, Twilight Gulch, ‘oupiee Co., Idaho, June 23, 1910 (distributed as P. speciosus Dougl.); 1774, House eek: Owyhee Co., Idaho, June 29, 1912; 2157, Bieroth’s Ranch (McDonald Creek), Nevada, August 2, 1912. PENTSTEMON PERPULCHER pandus, n. var.—Smaller than the species, the leaves more or less curved or arcuate: puberulence very dense, that of the stem extending to the rachis but not to the pedicels and calyx. No. 1884, July 2, 1912, on the high plains, near the ‘‘ Hot Hole” of the East Bruneau is the type Downingia brachyantha (Rydb.), n. comb.—Bolelia brachyantha Rydb., Mem. N.Y. Bot. Gard. 1:458. 1900. Downingia corymbosa (A. DC.), n. comb.—Clintonia corym- bosa A. DC. Prodr. '7:347. 1838. Because of some splendid specimens secured of these species in the field work of 1912, our attention has been called to the fact that in accordance with the action of the Vienna Congress (‘‘nomina conservanda”’) these species must be transferred. Erigeron elkoensis, n. sp.—Plant low, subcinereous with a rather dense short more or less retrose pubescence throughout, with a short simple or sparingly branched caudex clothed with dead leaf- bases: stems few, simple, decumbent-ascending, monocephalous, leafy throughout or often naked-pedunculate above, about 4-10 cm. long: leaves numerous on the crowns, 2-4 cm. long including the petiole, oblong-spatulate, subacute, tapering to a narrowly winged petiole as long as or longer than the blade, inclined to be conduplicate; stem leaves similar, becoming smaller upward and linear: heads large, 20-25 mm. broad: bracts lance-linear, acute, unequal, one-nerved, in 2-3 series, the inner scarious-margined, 1913] NELSON & MACBRIDE—WESTERN PLANTS 383 entire or fimbriate, granular-glandular, the outer green, hirsute as well as glandular: rays 15-20, conspicuously purple, rather broad, 3-toothed at apex: disk flowers yellow: achenes (young) pubescent. In habit this suggests E. leiomeris Gray, but in other respects is very differ- ent. No. 2068, secured on open pebbly slopes, near Pole Creek in the Burnt Timber Mountains, Elko Co., Nevada, is the type ERIGERON POLIOSPERMUS latus, n. var.—Rougher pubescent than in the typical form, the crowns of the caudex clothed with dead leaf-bases: leaves unusually broad (3-4 mm.): heads large, very broad (the disk about 15 mm.) and the rays rather long and broad: involucre sparsely hispid, with the tips of the bracts granular-glandular, otherwise nearly or quite naked: rays purplish to white: achenes brown, glabrate. This was a most striking plant on the black volcanic sands on which it was secured. In habit and aspect it suggested the EZ. compositus group rather than its real affinity, and led to its being tentatively designated as a species, E. Jatus. The technical characters, however, scarcely warrant such a disposition. Three Creek, Owyhee Co., Idaho, no. 1861, July 1, 1912: Rocky MountTAIn HERBARIUM UNIVERSITY OF WyomInc, LARAMIE SIR JOSEPH DALTON HOOKER F. O. BOWER ey [In a memorial oration delivered at the University of Glasgow, June 25, 1912, Professor BOWER spoke of Sir JosepH D. Hooker as a traveler, a geog- rapher, a geologist, a morphologist, an administrator, a scientific systematist, and a philosophical biologist. There is danger that HooKer’s great contri- butions to taxonomy will overshadow, for the biologists of a later generation, his important relation to the development of evolutionary theory. With the permission of Professor Bower, therefore, that part of his oration dealing with Hooker as a philosophical botanist is here reproduced.—Ep1Tor.] I hope I have not wearied you with these brief sketches of four of the great systematic works of Sir JosepH Hooker. I have gone somewhat more into detail than is quite justified in a public speech. But this has been done with a definite end in view. It was to show you how fully he was imbued with the old systematic methods; how he advanced, improved, and extended them, and was in his time their chief exponent. His father had held a similar position in the generation before him. But the elder HooKEr, true to his generation, treated his species as fixed and immutable. He did not generalize from them. His end was attained by their accurate recognition, delineation, description, and classification. The younger Hooker, while in this work he was not a whit behind the best of his predecessors, saw further than they. He was not satisfied with the mere record of species as they were. He sought to penetrate the mystery of the origin of species. In fact, he was not merely a scientific systematist in the older sense. He was a philosophical biologist in the new and nascent sense of the middle period of the nineteenth century. He was an almost life-long friend of CHARLES DARWIN. He was the first confidant of his species theory, and, excepting WALLACE, its first whole-hearted adherent. But he was also DArwitn’s constant and welcome adviser and critic. Well indeed was it for the successful launch of evolutionary theory that old-fashioned systematists took it in hand. Both Darwin and Hooker had wide and detailed knowledge of species as the starting-point of their induction. Botanical Gazette, vol. 55] [384 1913] BOWER—SIR JOSEPH HOOKER 385 Before we trace the part which Hooker himself played in the drama of evolutionary theory, it will be well to glance at his personal relations with DARWIN himself. It has been seen how he read the proof-sheets of the Voyage of the Beagle while still in his last year of medical study. But before he started for the Antarctic he was introduced to its author. It was in Trafalgar Square, and the interview was brief but cordial. On returning from the Antarctic, correspondence was opened in 1843. In January 1844 HooKER received the memorable letter confiding to him the germ of the theory of descent. Darwin wrote thus: ‘At last gleams of light have come, and I am almost convinced that species are not (it is like confessing a murder) immutable: I think I have found (here’s presumption!) the simple way by which species become exquisitely adapted to various ends.” This was probably the first communi- cation by Darwin of his species theory to any scientific colleague. The correspondence thus happily initiated between Darwin and Hooker is preserved in the Life and letters of Charles Darwin, and in the two volumes of Letters subsequently published. They show,on the one hand, the rapid growth of a deep friendship between | these two potent minds, which ended only beside the grave of Dar- WIN in Westminster Abbey. But what is more important is that these letters reveal, in a way that none of the published work of either could have done, the steps in the growth of the great generali- zation. We read of the doubts of one or the other; the gradual accumulation of material facts; the criticisms and amendments in face of new evidence; and the slow progress from tentative hy- pothesis to assured belief. We ourselves have grown up since the clash of opinion for and against the mutability of species died down. It is hard for us to understand the strength of the feelings aroused, the bitterness of the attack by the opponents of the theory, and the fortitude demanded from its adherents. It is best to obtain evidence on such matters at first hand, and this is what is supplied by the correspondence between Darwin and Hooker. How complete the understanding between the friends soon became is shown by the provisions made by Darwin for the pub- lication of his manuscripts in case of sudden death. He wrote in August 1854 the definite direction “‘HooKER by far the best man 386 BOTANICAL GAZETTE [MAY to edit my species volume,” and this notwithstanding that he writes to him as a “stern and awful judge and sceptic.” But again, ina letter a few months later, he says to him “I forgot at the moment that you are the one living soul from whom I have constantly received sympathy.”’ I have already said that Hooker was not only Darwin’s first confidant, but also the first to accept his theory of mutability of species. But even he did not fully assent to it till after its first publication. The latter point comes out clearly from the letters. In January 1859, six months after the reading of their joint communications to the Linnaean Society, DarRWIN writes to WALLACE ‘‘You ask about LyYELL’s frame of mind. I think he is somewhat staggered, but does not give in... . . I think he will end by being perverted. Dr. HOOKER has become almost as heterodox as you or I, and I look at HooKER as by far the most capable judge in Europe.”’ In September 1859 DaRWIN writes to W. D. Fox ‘“‘LyYELt has read about half of the volume in clean sheets. : . . . He is wavering so much about the immutability of species that I expect he will come round. HooKER has come round, and will publish his belief soon.’”’ In the following month, writing to HooKER, DARWIN says: “I have spoken of you here as a convert made by me: but I know well how much larger the share has been of your own self-thought.” A letter to WALLACE of November 1859 bears this postscript: ‘‘I think that I told you before that Hooker is a complete convert. If I can convert Huxtey I shall be content.” And lastly, in a letter to W. B. CARPENTER, of the same month, DARWIN says: ‘“‘As yet I know only one believer, but I look at him as of the greatest authority, viz. HooKER.”’ These quotations clearly show that, while LYELL wavered, and HuxLey had not yet come in, HOOKER was a com- plete adherent in 1859 to the doctrine of the mutability of species. Excepting WALLACE, he was the first, in fact, of the great group that stood round DArwyy, as he was the last of them to survive. The story of the joint communication of DARWIN and of WAL- LACE to the Linnaean Society ‘‘On the tendency of species to form varieties, and on the perpetuation of varieties and species by natural means of selection” will be fresh in the minds of you all, for the fiftieth anniversary of the event was lately celebrated 1913] BOWER—SIR JOSEPH HOOKER 387 in London. It was Sir CHARLES LYELL and Sir JosepH HOOKER who jointly, and with the author’s permission, communicated the _ two papers to the society, together with the evidence of the priority of DARWIN in the inquiry. Nothing could then have been more apposite than the personal history which Sir JosEPH gave at the DaRWIN-WALLACE celebration, held by the Linnaean Society in 1908. He then told, at first hand, the exact circumstances under which the joint papers were produced. Nor could the expressions: used by the President when thanking Sir Josepn, and presenting to him the DARwin-WALLACE Medal, have been improved. He said: ‘‘The incalculable benefit that your constant friendship, advice, and alliance were to Mr. DARWIN himself, is summed up in his own words, used in 1864: ‘You have represented for many years the whole great public to me.’”” The President then added: “Of all men living it is to you more than to any other that the great generalization of DARWIN and WALLACE. owes its triumph.’” aving thus sketched the intimate relations which subsisted between Hooker and Darwny, it remains to appraise his own positive contributions to philosophical biology. He himself, in his address as President of the British Association at Norwich in 1868, gives an insight into his early attitude in the inquiry into biological questions. ‘‘Having myself,’ he says, ‘‘been a student of moral philosophy in a northern university, I entered on my scientific career full of hopes that metaphysics would prove a useful mentor, if not a guide in science. I soon found, however, that it availed me nothing, and I long ago arrived at the conclusion so well put by Acassiz, when he says ‘We trust that the time is not distant when it will be universally understood that the battle of the evidences will have to be fought on the field of physical science, and not on that of the metaphysical.’”’ This was the difficult lesson of the period when evolution was born. Hooker learned the lesson early. He cleared his mental outlook from all precon- ceptions, and worked down to the bed-rock of objective fact. Thus he was free to use his vast and detailed knowledge in advancing, along the lines of induction alone, toward sound generalizations. These had their very close relation to questions of the mutability of species. The subject was approached by him through the study 388 BOTANICAL GAZETTE [MAY of geographical distribution, in which, as we have seen, he had at an early age become the leading authority. The fame of Sir JosepH HooKeER as a philosophical biologist rests upon a masterly series of essays and addresses. The chief of these were the introductory essay to the Flora Tasmaniae, dealing with the antarctic flora as a whole; the essay on the dis- tribution of arctic plants, published in 1862; the discourse on insular floras in 1866; The Presidential aii to the British Association at Norwich in 1868; his address at York, in 1881, on geographical distribution; and finally, the essay on the vegeta- tion of India, published in 1904. None of these were mere inspira- tions of the moment. They were the outcome of arduous journeys to observe and collect, and subsequently of careful analysis of the specimens and of the facts. The dates of publication bear this out. The essay on the antarctic flora appeared about twenty years after the completion. of the voyage. The essay on the vegetation of India was not published till more than half a century after Hooker first set foot in India. It is upon such foundations that HOOKER’s reputation as a great constructive thinker is securely based. The first-named of these essays will probably be estimated as the most notable of them all in the history of science. It was com- pleted in November 1859, barely a year after the joint communica- tions of DARWIN and WALLACE to the Linnaean Society, and before the Origin of species had appeared. It was to this essay that Dar- WIN referred when he wrote that ‘‘Hooker has come round, and will publish his belief soon.” But this publication. of his belief was not merely an echo of assent to DARWIN’s own opinions. It was a reasoned statement, advanced upon the basis of his “own self- thought,’ and his own wide systematic and geographical expe- rience. From these sources he drew for himself support for the ‘hypothesis that species are derivative and mutable.” He points. out how the natural history of Australia seemed specially suited to test such a theory, on account of the comparative uniformity of the physical features being accompanied by a great variety in its flora, and the peculiarity of both its fauna and flora as compared with other countries. After the test had been made, on the basis _of the study of some 8,000 species, their characters, their spread, 1913] BOWER—SIR JOSEPH HOOKER 389 and their relations to those of other lands, he concludes decisively in favor of mutability and a doctrine of progression. How highly this essay was esteemed by his contemporaries is shown by the expressions of LYELL and of Darwin. The former writes ‘‘I have just finished the reading of your splendid essay on the origin of species, as illustrated by your wide botanical expe- rience, and think it goes far to raise the variety-making hypothesis to the rank of a theory, as accounting for the manner in which new species enter the world.””. DARwInN wrote ‘‘I have finished your essay. To my judgment it is by far the grandest and most interest- ing essay on subjects of the nature discussed I have ever read.” But besides its historical interest in relation to the species ques- tion, the essay contained what was, up to its time, the most scientific treatment of a large area from the point of view of the plant- geographer. He found that the antarctic, like the arctic flora, is very uniform round the globe. The same species in many cases occur on every island, though thousands of miles of ocean may intervene. Many of these species reappear on the mountains of Southern Chile, Australia, Tasmania, and New Zealand. The southern temperate floras, on the other hand, of South America, South Africa, Australia, and New Zealand, differ more among them- selves than do ‘the floras of Europe, Northern Asia, and North America. To explain these facts he suggested the probable former existence, during a warmer period than the present, of a center of creation of new species in the Southern Ocean, in the form of either a continent or an archipelago, from which the antarctic flora radi- ated. This hypothesis has since been held open to doubt. But the fact that it was suggested shows the broad view which he was pre- pared to take of the problem before him. His method was essen- tially that which is now styled “ecological.” Many hold this to be a new phase of botanical inquiry, introduced by Professor WARMING in 1895. No one will deny the value of the increased precision which he then brought into such studies. But in point of fact it was ecology on the grand scale that Sir JosepH HOOKER practiced in the Antarctic in 1840. Moreover, it was pursued, not in regions of old civilization, but in lands where nature held her sway untouched by the hand of man. This essay on the flora of the Antarctic was the prototype of 39° BOTANICAL GAZETTE [MAY the great series. Sir JOSEPH examined the arctic flora from similar points of view. He explained the circumpolar uniformity which it shows, and the prevalence of Scandinavian types, together with the peculiarly limited nature of the flora of the southward penin- sular of Greenland. He extended his inquiries to oceanic islands. He pointed out that the conditions which dictated circumpolar distribution are absent from them, but that other conditions exist in them which account for the strange features which their vegetation shows. He extended the application of such methods to the Himalaya and to Central Asia. He joined with Asa GRAY in like inquiries in North America.- The latter had already given a scientific explanation of the surprising fact that the plants of the eastern states resemble more nearly those of China than do those of the Pacific slope. In resolving these and other problems, it was not only the vegetation itself that was studied. The changes of _ climate in geological time, and of the earth’s crust as demonstrated by geologists, formed part of the basis on which he worked. For it is facts such as these which have determined the migration of floras. And migration, as well as mutability of species, entered into most of his speculations. The essays of this magnificent series are like pictures painted with a full brush. The boldness and mastery which they show sprang from long discipline and wide experience. Finally, the chief results of the phytogeographical work of himself and of others were summed up in the great address on “Geographical distribution” at York. The Jubilee of the British Association was held there in 1881. It had been decided that each section should be presided over by a past President of the Association, and he had occupied that position at Norwich in 1868. Accordingly at York, Hooker was appointed President of the Geographical Section, and he chose as the subject of his address “The geographical distribution of organic beings.’ To him it illustrated “the interdependence of those sciences which the geographer should study.” It is not enough merely to observe the topography of organisms, but their hypsometrical distribution must also be noted. Further, the changes of area and of altitude in exposed land surfaces of which geology gives evidence, are 1913] BOWER—SIR JOSEPH HOOKER 301 essential features in the problem, together with the changes of climate, such as have determined the advance and retrocession of glacial conditions. Having noted these factors, he continued thus: “With the establishment of the doctrine of orderly evolution of species under known laws, I close this list of those recognized principles of the science of geographical distribution, which must guide all who enter upon its pursuit. As HumBoLpT was its founder, and Forses its reformer, so we must regard DARWIN as its latest and greatest lawgiver.’’ Now, after thirty years, may we not add to these words of his, that HOOKER was himself its greatest exponent ? You will have felt how tenuous is the line of limitation, if line indeed there be, between morphological reality and- morphological abstraction; between the unit observed, and the summation of such units into a progression; between the static and the dynamic study of living things. It was this line that was crossed by Darwin; and, as I have shown, Hooker was the first of his friends to follow. To the general public he was perhaps the least known of the great triumvirate of Glasgow. The results he achieved do not touch everyday life so nearly as those of KELvin or of Lister. This is perhaps natural, for while he was the leading botanist of his time, he was, before all, a philosopher. In him we see the foremost stu- dent of the broader aspects of plant life at the time when evolution- ary belief was nascent. His influence at that stirring period, though quiet, was far-reaching and deep. His work was both critical and constructive. His wide knowledge, his keen insight, his fearless judgment were invaluable in advancing that intellectual revolution which found its pivot in the mutability of species. The share he took in promoting it was second only to that of his life- long friend, CHARLES DARWIN. UNIversITy or GLASGOW THE LICHENS OF MT. ROSE, NEVADA Atnent W. C. T, HERRE Mt. Rose, with an altitude of 10,800 ft., is the highest peak in the region about Lake Tahoe, and lies about 15 miles southwest of Reno, Nev. A forest of Pinus ponderosa extends from the base of the peak at an approximate elevation of 6000 ft. to perhaps 8000 ft. The higher elevations on to the timber line, which is at an altitude of about 10,000 ft., are covered more or less by Tsuga mertensiana, Libocedrus decurrens, and Pinus monticola. During the Comstock boom this timber was greatly depleted, parts being deforested even up to the timber line. Along the water courses are scattered Salix sp., Amelanchier sp., and various smaller shrubs. Above 8000 ft. a large part of the mountain, in common with all the ranges about, is bare of trees and strewn with bowlders or plentifully sprinkled with dikes and outcrops of rock. The remarkably original and valuable observations of Dr. J. E. Cuurcu, of the University of Nevada, have furnished us with our knowledge of the climatology of Mt. Rose. For a number of years he has maintained on this isolated and well-nigh inaccessible peak a meteorological station unique in America. For a large part of the year snow lies upon the upper part of the peak, while at no time of the year is it entirely absent except where the winds keep the rock ledges swept bare. Snow may fall in quantity at any time of the year, though in late summer it nearly disappears, and when fresh-fallen lies but a short time. In the forested portion of the higher altitudes the snow forms great mounds which act as storage tanks, supplying water gradually to the lower levels. The summit temperatures are not excessively low, though of course cold weather prevails much of the time; —10° F. is the lowest recorded, but freezing weather occurs at any time of the year. The most noticeable features of the lichen flora of the mountain are, so far as my observations extend, the utter absence of bark- dwelling species or those of dead or decorticated wood, and the equally conspicuous absence of earth lichens. Botanical Gazette, vol. 55] [392 1913] HERRE—LICHENS OF MT. ROSE 303 In part, at least, the absence of corticolous lichens is due directly to the winds of enormous velocity which are prevalent in this region. Gales of 50 miles an hour are frequent, while at times the inordinate velocity of 150 to 170 miles an hour is reached. As these winds sweep the mountain slopes, they carry sand or dust, sleet, and fine hard snow; the abrasive action of this flying material affects the bark of the conifers upon which it impinges in such a way that they appear as if freshly sandpapered. I was unable to find any indication of either lichens or mosses upon the bark of any tree or shrub examined. The dearth of earth lichens may be in part explained by other causes, such as excessive dryness, the erosive action of floods caused by the rapid melting of snow when the Chinook winds blow in early spring, etc. But as yet I cannot understand the failure to find any trace of such genera as Cladonia, Stereocaulon, Solorina, Cetraria, and similar genera containing species characteristic of alpine situations. Perhaps prolonged search in early summer just after the disappearance of the greater part of the snow would reveal some of them. The conditions noted above offer no hindrance to the growth of rock lichens. In the wooded slopes lichens occur on all rocks, but ms abundantly, even where not shaded by the pines. But at ooo ft. one comes suddenly into a region where lichens are both stieeese numerous and remarkably conspicuous. From here to the summit the dominant species is Gyrophora reticulata, which is excessively abundant; but the great bowlders strewing the mountain side and obstructing the trail are also spotted and blotched with huge, brilliant masses of Acarospora chlorophana, while Caloplaca elegans lends a gleam of fire to the somber landscape. The number of species occurring from here to the summit is very small, but this is amply compensated for by the number of indi- viduals found in what one may term the Gyrophora reticulata formation. The species collected were as follows: 1. Staurothele umbrina (Ach.) Tuck.—Forming dark stains on rocks along the summit. 2. Lecidea atrobrunnea (Ram.) Schaer.—Abundant on all kinds of rocks at 8000 ft. and above; exceedingly variable, and perhaps 304 BOTANICAL GAZETTE [way I have included more than one species, but as the more aberrant forms do not have fertile asci I cannot place them elsewhere. Varying in color from a clear saddle brown to black-brown. Much infested by a parasitic fungus which causes black, morbid, apothecia-like growths. 3. Lecidea plana Lahm.—lIdentification doubtful, but agrees in all essentials. 4. Gyrophora rugifera (Nyl.) Th. Fr. old on the south side of ledges at 10,800 ft. and for several hundred feet below; not found on the north side of the mountain. Growth luxuriant, but very rarely fertile. 5. Gyrophora reticulata (Schaer.) Th. Fr. —Excessively abundant from 8000 ft. upward. Occurring in all kinds of situations and forming the dominant lichen. Rather variable, but all forms may be referred to this species, whether typically foliose or reduced to a dense, uniform, crustaceous rock covering. According to the investigations of Dr. R. HEBER Howe, who has recently examined the lichen types of the Linnaean Herbarium, Lichen deustus of LINNAEUS is really G. reticulata, which therefore becomes a synonym of G. deustus (Lin.) R. H. Howe. 6. Acarospora chlorophana (Wahlb.) Mass. 7. Acarospora cervina (Pers.) Koerber. 8. Acarospora thermophila Herre, n. sp.—Thallus somewhat orbiculate to effuse, areolate and fissured, of small lobulate squam- ules which are more or less stalked or stipitate beneath, the clustered stalks often branched, their height reaching 7 mm. Surface of squamules imbricate-lobate, the lobes very small, except marginally where they may be slightly expanded. Upper surface a pale yellow-brown or clay-brown; beneath black. No reactions visible. Apothecia rare, small to medium, solitary or several grouped together, their surface more or less roughened and wrinkled, or sometimes fissured; an evident narrow thalline margin present; -epithecium yellow-brown; hypothecium yellowish or very pale brownish; thecium colorless, turning to very deep blue with [; paraphyses simple, not septate, subcoherent, slender, their tips not enlarged; asci broadly clavate or top-shaped, measuring 24 .8- 1913] HERRE—LICHENS OF MT. ROSE 305 30.5 # in breadth by 61-68 # in length; spores colorless, exceed- ingly numerous, short ellipsoid to subglobose, 1~2 # broad by 2-4.5 & long. Common on rocks everywhere in the desert about Reno, Nev., at an alti- tude of 4709 to 6000 ft.; not rare on Mt. Rose at 8000 ft. and above, and abundant in the Sierras along the Truckee River near the Nevada-California state line at an altitude of 6000 ft. In a preceding paper (Bot. Gaz. 51:286-297. 1911) this plant was mistakenly called by me Acarospora thamnina. It is certainly the most successful xerophyte of the Nevada desert, growing in the driest places, where it is exposed to the most intense light and heat. The apothecia are rarely developed, but the scales are commonly covered with a parasitic fungus so that they appear fertile, but their true condition is readily shown by careful sectioning. g. Acarospora thamnina (Tuck.) Herre.—Leconora thamnina Tuck., Genera Lichenum, 120. 1872; L. cervina b. thamnina Tuck., Synopsis 1:202. 1882.—Thallus of small, dense irregular clumps 8-15 or rarely 25 mm. or more in diameter, with domelike or irregu- larly rounded surface, or more or less flattened. On closer examina- tion the surface is seen to be made up of a great number of small to minute, closely appressed, and highly irregular, plicate, or even imbricate, lobulate squamules; these are continued downward into stems which coalesce to form finally flattened, rootlike stipes, the whole clump with its basal stipe reaching a height of 10-15 mm. in well grown specimens. Color various shades of brown; often gray or bluish-gray pruinose; usually more or less blackened by a parasitic fungus; the under surface dead black. No reactions observable. Apothecia rare, small or minute, o.2-0.8mm. in diameter, rarely more than one in squamule, immersed, their surface more or less roughened or gyrose; thalline margin entire, rather thick; much darker in color than the thallus; epithecium yellow; hypo- thecium pale; paraphyses simple, straight, their tips not enlarged, Oleoguttate, 1-2.7 " broad; asci cylindrical, 13-18» broad by 48-55 « long; when treated with I the colorless thecium is first blue, then wine-red, and finally tawny; spores short ellipsoid to ellipsoid, o.75-1.25 » broad by 3.3-4.5 » long. 306 BOTANICAL GAZETTE [MAY A rare plant, known only from the cold high Sierras. Collected by BOLANDER at Mono Pass in 1867, and so far as I know not reported authenti- cally by others. Occurring on earth deep in the crevices of rocks beside the observatory on the summit of Mt. Rose, associated with Gyrophora rugifera. For the determination of this singular Acarospora I am indebted to Dr. W. G. Fartow, who kindly compared my material with that in the Tucker- man Herbarium. 10. Lecanora rubina (Vill.) Ach. 11. Lecanora melanophthalma (DC.) Jatta. 12. Candelariella cerinella (Flk.) A. Zahlbr.—On rocks at 10,800 ft. and also on the thallus of other lichens. 13. Blastenia ferruginea (Huds.) Arn.—On the thallus of other lichens and also on rocks at 10,800 ft. 14. Caloplaca elegans (Link) Th. Fr.—Common at all elevations from 8000 ft. to the summit. 15. Caloplaca murorum (Hoftm.) Th. Fr.—Not very abundant at 8000 ft. _ 16. Xanthoria lychnea laciniosa (Schaer.).—On the thallus of Gyrophora rugifera and in crevices of rocks at 10,800 ft.; not very plentiful. 17. Physcia tribacia (Ach.) Tuck.—A few small, sterile speci- mens were collected at 8000 ft. and at 10,800 ft. Everson, WASH. BRIEFER ARIICLES A NEW WOOD-DESTROYING FUNGUS. (WITH SIX FIGURES) A very interesting polypore was sent to Professor ATKINSON at the botanical laboratory of Cornell University during the winter of 1912-13. The plant, collected by Dr. F. A. WorF at the Alabama Polytechnic Insti- tute,was found growing on some of the woodwork in the engineering build- ing, where it was apparently causing considerable damage. A stairway and floor situated near water pipes were so badly rotted that it was neces- sary to replace them, and the wainscoting under the steps was entirely covered with a layer of mycelium, which was at first yellow and later dark brown. An examination showed that the mycelium was growing through the wood and also over the exposed surfaces, where it produced a soft papery layer of pale umbrinous color which could be easily sepa- rated from the substratum. In manner of growth and the appearance of the mycelium, the plant resembles Merulius lacrymans, but instead of the hymenophore being composed of the vermiform, anastomosing folds of that genus, a stratum of dark fuligineous pores was formed (figs. 1-3). The tubes were very fragile and friable when dry, the condition in which the fungus was found. A microscopic examination showed that the color of the tubes was almost entirely due to the very numerous dark brown spores which filled the pores and were often massed on the sur- rounding mycelium. The trama of the pores and the subiculum on which they were formed were composed of pale umbrinous hyphae (figs. 4, 5). The wood on which the fungus was growing was in advanced stages of decay, of a dark brown color and checked into small cubes. Much of it could be crumbled between the fingers, and when sections were cut the spring wood separated from the summer wood. A part of the wood was bald cypress (Taxodium distichum) and a part long leaf pine (Pinus palustris). Strange to say, in the cypress the late or summer wood, which is more resinous, was more badly decayed than the spring wood, which in some places remained quite firm. The reverse was true in the pine; the spring wood in some instances was reduced almost to a powder, while the summer wood remained intact. All attempts to germinate the spores or to get a culture from the mycelium in the wood failed, so that no work with pure cultures, to find the action of the fungus on the wood or to determine with certainty that it was responsible for the decay present, was possible. 397] [Botanical Gazette, vol. 55 398 BOTANICAL GAZETTE [MAY This plant seems to occupy a position in the Polyporeae similar to that of Merulius lacrymans and related species in the Meruliae and to Coniophora among the Thelephoraceae. It has the same dark dusty . Fics. 1-6.—Poria atrosporia: figs. 1, 2, portions of fruiting surface, nat. size; fig. , Same, X2; fig. 4, photomicrograph of section through pores, X10; fig. 5, same. noe te 6, nicktealoneatanh of spores. spore mass and the light colored mycelium forming thin sheets over the substratum. The spores of Coniophora cerebella and Merulius lacrymans are slightly different in color, being more brown than fuligineous, and those of Coniophora cerebella larger than the spores of this species, but they are of the same shape (fig. 6). 1013] BRIEFER ARTICLES 399 Search through the literature of described species revealed no plant of like character. It is therefore described as a new species, and pro- visionally placed in the genus Poria, although it is recognized that the plants of this genus are a heterogeneous group which sooner or later will be separated into several genera or distributed among the genera of pileate forms with which they correspond in texture and other characters The specific name atrosporia is given because of the abundance of dark spores. A technical description is as follows: Poria atrosporia, n. sp.—Mycelium within the substratum or in a superficial layer of soft cottony or thin papery consistency; color pale umbrinous:. sporophore resupinate, broadly effused, easily separable: margin sterile, pale umbrinous: hymenophore porose, not stratose, very fragile and friable when dry; pores 1-5 mm. deep, dissepiments thin, mouths irregular to subrotund, 1-5 to a mm.: trama pale umbrinous, but pores deep fuligineous because of the abundance of dark spores; spores oval, dark brown, 4-5.5X8-10; cystidia none. Habitat, structural timber of coniferous wood. Mycelio substratum penetrante vel stratum superficitum byssinum vel papyraceum formante; sporophora resupinata, late effusa, a matrice separabilis; margine sterili, umbrino-pallido; poris non stratosis, siccatis fragilis et friabilis, 1-5 mm. longis; parietibus tenuibus; ore irregulari vel subcirculari, I-§ quoquemm.: trama umbrina-pallida sed poris fuligineis ob copiosos umbrinos; sporis ovatis 4-5.58-10p; cystidiis nullis. Hab. ad ligna fab- ricata coniferarum.—ADELINE AMES, Cornell University, Ithaca, N.Y. A SAFETY RAZOR MODIFIED FOR CUTTING HAND-SECTIONS (WITH ONE FIGURE) Since the advent of the many styles of “safety razors,” biologists have looked with covetous eye upon their keen and cheap blades, seem- ingly unadapted to any purpose except that intended by the manu- facturer. Microtomists have produced several devices to utilize these keen edges and at the same time hold the blades solidly so as to avoid trembling, but, so far as I am aware, none of these razors has been used for hand-sectioning, or, if the blades have been used, the handles have been of no assistance. Some time ago, needing section razors for the use of large classes, I looked over the various kinds of safety razors for sale in shops and found among them one known as the “ Durham-Duplex,” which, by slight modification, has become very well adapted to the purposes for which 400 BOTANICAL GAZETTE [MAY students have need of a section cutter. This razor has two advantages over most safety razors, so far as our present purposes are concerned. In the first place, it is much like an old-style razor in general shape, the blade, however, being removable and pro- tected by a nickel- plated brass guard. In the second place, the blades are thicker, longer, and stiffer than those provided with most safety razors. Mw AT ham- Demonstrator.” As shown by 4, the pro- tecting shield has been cut away so as to leave a portion of the blade exposed for use. The other drawing (b), show- Fic. 1—Modified safety razor: explained in text ing the other side of the razor, illustrates the cutting off of the brass supporting handle, thus leaving the blade free beneath. A screw fitted into the handle at the base of the blade is at once the means of holding the latter rigid, as well as of permitting its easy removal for cleaning or changing the cutting edge, the slot filed into the base of the guard making of this a very simple operation. In practice this razor has proved very successful with large classes, providing an abundance of sharp edges as well as saving the time of an assistant on whom the work of honing would otherwise fall.—J. P. GIVLER, Southwestern College, Winfield, Kansas. ON STEMONITIS NIGRESCENS AND RELATED FORMS That MacsripE, in his North American slime-moulds, retains Stemonitis nigrescens Rex as a distinct and well marked species, while the - Listers, in their Monograph of the Mycetozoa, réfer it unhesitatingly 1913] BRIEFER ARTICLES 401 and with only the briefest comment to S. fusca, seems to warrant some further elucidation. Judging by the type specimen only, a portion of which was sent to me some years ago by the late Dr. REx, one would be justified in according to his species at least varietal rank. The strikingly dark color, the stiff, upright habit of the sporangia, not curved or drooping even at the edges of the clusters, and their small size (stalk less than 1 mm., total height 4.5 mm. or less) are features which appear to render this form recognizable at sight. Moreover, many gatherings made during the past ten years in as widely separated locali- ties as New England and Colorado show that this dark, dwarf form is fairly common in the United States. It should be noted also that with the distinct external features noted above certain microscopic features are usually associated, such as a more or less imperfect development of the surface net, the meshes of which show spinelike processes, and reticulated spores of a smoky-brown color. A number of gatherings made in Colorado, however, throw light on the variable character of S. nigrescens. Seven such gatherings are before me. They all agree in the short-stalked, upright, dwarf habit, and in the reticulated spores. But the color of the clusters of sporangia varies markedly from dull ferruginous to almost black; the surface net in one of the specimens is as perfectly developed and as free from spinous processes as in any typical specimen of S. fusca; while the spores vary in color from pale to dark smoky-brown, the former showing a very faint and delicate reticulation which is much more pro- nounced in the case of the darker-spored specimens. I cannot but conclude that these are all forms of one and the same species, and that they should be regarded as a dwarf variety of Stemonitis fusca Roth. This opinion is strengthened by the examination of a specimen collected at Pagosa Springs, Colorado, in August 1911. It shows the same dense clusters of stiff, upright, dark smoky-brown sporangia, short-stalked, and measuring less than 4mm. in height. The small- meshed surface net shows a few small spines. The spores, 8.9 in diameter, are rather dark in color, but instead of being reticulated they are closely and minutely spinulose. In my opinion this is a dwarf form of Stemonitis herbatica Peck, and bears the same relationship precisely to that species as do the dwarf forms commented on above to S. fusca. I conclude, therefore, that the Listers were correct in merging S. nigrescens Rex with S. fusca Roth, but that the former constitutes a well marked variety, though ill-defined by the designa- tion nigrescens—W. C. Sturcis, Colorado Springs, Colorado. CURRENT. LITERATURE BOOK REVIEWS Physiological plant anatomy The appearance of a fourth edition of HABERLAND?’s well known work,* almost exactly 25 years after the first edition was published, is an indication of the importance of the book and the service it has rendered to the physiological aspect of plant anatomy. The previous edition, reviewed in this journal,’ has been completely revised, and the changes, although limited in extent, serve to incorporate the results of more recent investigation. The number of pages has been increased from 616 to 650, and the illustrations from 264 to 201. Among the additions are sections entitled “Einrichtungen fiir besondere mechanische Leistungen,” which include the discussion of various hairs and hooks functioning as supports of climbing plants; and “Speichergewebe fiir Atmungsstoffe” and ‘“‘Speichergewebe fiir dkologische Zwecke,” dealing with certain aspects of the storage tissues of plants, but presenting little new data. The most important changes appear in the twelfth chapter, entitled “Die Sinnesorgane,”’ which has been entirely rewritten, with the inclusion of much new material. Foremost among the new data are the results of the author’s studies on the structure for light perception in leaves. They include the various lens cells or ocelli, as well as various cells below smooth outer sur- faces. Several papers presenting these data have already been noted in these pages. Both in this chapter and elsewhere in the volume the author maintains his well known teleological interpretation of the date in spite of the opposite trend of modern investigation. Fortunately this does not detract from the importance of his experiments or the accuracy of his data.—Gro. D. FULLER. MINOR NOTICES 3 : Key to trees.—The authors‘ of a Key to New England trees have again given us a convenient and reliable pocket manual pertaining to our native *HABERLANDT, G., Physiologische Pflanzenanatomie. Vierte, Neubearbeitete, und vermehrte ad Imp. 8vo. xviii+650. figs. 29r. Leipzig: Wilhelm Engel- mann, 1909. M1 2 Bor. Gaz. aiik 1904. 3 Cotiins, J. FRANKLIN, and Preston, Howarp W., Illustrated key to the wild and sania cultivated trees of the northeastern United States and adjacent Canada. Small 8vo. pp. ation bes 279. New York: Henry Holt & Co. 1912. $1.35 in cloth, $2.50 in leath 4 Bot. GAz. 423399. a and Bor. Gaz. 48:472-474. 1909. 402 1913] CURRENT LITERATURE 403 trees and those common in cultivation in the northeastern United States and adjacent Canada. The book is free from unnecessary technical terms and descriptive details which are essential to a comprehensive flora, so that the u reproduced photograph in halftone of the bark. Each tree is given its scientific name, as well as the common name by which it is known. The drawings are all made in actual proportions, the natural size being shown graphically by a line-scale accompanying each figure. We need more such books to encourage and popularize careful field observation.—J. M. GREENMAN. Officinal plants and drugs.—Mzurtacuer’s has brought together in convenient compilation the plants recognized in all of the approved pharma- copoeias, 22in number. ‘The nomenclature is that of the Vienna Congress, and the sequence is that of WeTTsTEIN’s Handbuch. The data given are as follows: geographical distribution and culture of medicinal plants, the vegetation form, the drugs obtained, those drugs regarded as especially strong and those recog- nized as “officinal’”’ in different countries, etc. It is interesting to note the distribution of these 638 officinal plants, representing 125 families. Of the cryptogams, only 23 such plants are used (Phaeophyceae 2, Rhodophyceae 7, Fungi 7, Pteridophytes 7), representing x6. families; while the gymnosperms add only 21 conifers. The 594 offi representing 107 families, are distribu sted: as «tolls: “Archichlamydeae 423; Sympetalae 197; and Monocotyledons 74.—J. M. C Illinois Academy of Science.—The volume of transactions of the fifth annual meeting (February 1912) of the Illinois Academy of Science has just appeared. A symposium on conservation includes “Conservation of our forests,” by HENRY C. Cow es, and “Conservation ideals in the improvement of plants,’ by H. J. Wesser. In addition to these papers, the following of botanical interest were presented: ‘Notes on the forests of Ogle County, Il., “ai by W. L. Erkenserry; ‘Competition and general relationships among the subterranean organs of onirei plants,” by Eart E. SHerrr; “The range of evaporation and soil moisture in the oak-hickory forest association of Illinois,” by Wave McNutt and Gero. D. Futter; and “Germination and growth of the cottonwood upon the sand dunes of Lake Michigan, near Chicago,” by Gro. D. Futter.—J. M. C. Volvox.—An extended discussion of Volvox, based upon living and fixed material mounted whole in glycerin jelly, is presented in a pamphlet by JANET.® ’MITLACHER, WILHELM, Die offizinellen Pflanzen und Drogen. pp. viii+13. Wien: Carle Fromme. 1912. M 6.25. 6 JANET, CHARLES, Le Volvox. 8vo. pp. 151. figs. 15. Limoges: Ducourtieux et Gott. 1912. fon” BOTANICAL GAZETTE [May The colony is compared with the blastula stage of animal embryology, and has a pore like the blastopore. The antheridium develops in the blastula fashion with a “phialopore,”’ as does also the new colony, whether formed asexually or from the egg. The figures are very diagrammatic, but interesting and prob- ably accurate. No nuclear detail is attempted. The most striking feature of the paper is the terminology. Every structure has a technical name, even when y literary French would serve as well.—CHARLES J. CHAMBERLAIN. NOTES FOR STUDENTS Inheritance in maize.—CoL.ins’ has made some interesting observations on the progeny of an all-white ear of maize that appeared suddenly in a field planted with a variety known as Gorham yellow dent. Since the character with which he was dealing develops in the endosperm and usually shows complete dominance in crosses, this variation is out of the ordinary. The author classes it as a case of mutative reversal of dominance. To the reviewer such a view respecting the phenomenon seems unwise. In the descendants of the seeds of this ear, yellow was dominant to lack of yellow in varying degrees; it only remains then to explain the non-development of yellow in the original aberrant ear. It has been generally accepted that dominance or lack of dominance is only another ih of SR. the somatic shpeeraice of a heterozygote. It has nothing to do with ly asan indication of zygotic composition. The true eadieation of any individual can be determined only by breeding from it, for there are characters so variable in their dominance that the appearance of the heterozygote may be similar to either homozygote (AA or aa). In spite of its variability, however, dominance does not just happen. It has its causes. An individual AA may be crossed with various kinds of aa individuals and the degree of dominance be different in each cross, but these various manifestations are due to internal differences between the aa organisms. On the other hand, external conditions may affect the manifestation of a character either when in a heterozygous or when in a homozygous condition. One may assume, therefore, that dominance is not a phenomenon of great variability when both external and internal conditions of development are identical. For these reasons, the reviewer has a suspicion that CoLLins’ mutative reversal of dominance was nothing but suppressed development due to some abnormal environmental condition, possibly the accidental presence of some particular metallic salt in the spot of soil in which the plant grew. The reviewer has observed somewhat similar phenomena, but has never thought his own ignorance of their exact cause a sufficient excuse for an attack on well established theories. Seeds from Co..ins’ “‘albinistic” ear were planted and the progeny investi- gated. His results show clearly that he was dealing with the behavior of two 7 Cottins, G. N., ssid of a maize variation. Bur. Pl. Ind. Bull. 272. pp. 23; pl. Fi fig. 8. 1933 1913] CURRENT LITERATURE 405 factors for yellow endosperm, Y; and Y;2, of which one is much more effective in producing the yellow pigment than the other. Such an assumption he regards as “‘violent,’’ it being just as violent as have been the assumptions of all Mendelian experimentalists who have made mathematical interpretations of breeding facts. The author is also greatly disturbed over the question of whether or not the segregation ratios that he obtained fit the theory of error. It seems to the reviewer, however, that considering the possibility of experi- h only variations of classification due to the difficulty of Totacabitos light yellows - from white, the author concludes “that while the segregation is usually numeri- cally exact, it is by no means complete; that is, the dominant character is not completely. absent from individuals of the recessive class.” ‘‘ This,” he says, “is shown not only by the presence of a faint yellow color in most of the seeds, but also by the fact that apparently pure white seeds from an ear in which the classes were well marked may produce seed with a fully developed yellow color when self-pollinated.”” Consequently he favors the idea of gametic impurity in the sense that extracted dominants and recessives may transmit traces of the alternative character. Again this conclusion seems opposed to the facts submitted. If one has a mother seeds proved to be 3:1; this the author either has not done or has not ry sche ms then the me ? ears obtsined . not again breed true, one might ; but the author reports no such evidence. ‘Ba a matter of fact, extracted recessives and extracted dominants do appear to throw the alternative character on rare occasions, but the phe- nomenon is so rare that one may better assume that a germinal rearrangement (mutation) has occurred. Of course in any species some variations are more likely to occur than others, which may be taken as evidence of a kind of latency. But this is only the kind of latency that is analogous to the tendency of a chlorine atom to split off from a complex benzene derivative, rather than one of the more conservative radicals such as methyl. It is evidence that certain rearrangements in a particular germ plasm are more likely to occur than others.—E. M. East Studies of Nicotiana hybrids.—In two papers, appearing almost simul- taneously, GoopspPEED® has reported the results of his investigations on Goopsprep, T. H., Quantitative studies of inheritance in Nicotiana hybrids. Univ. Calif. Publ. 5: no. 2. pp. 87-168. pls. 29-34. 1912; ibid. no. 3. pp. 169-188. 1913. 406 BOTANICAL GAZETTE [MAY possible correlations between seed characters and plant characters, and on the inheritance of certain quantitative character complexes in crosses between various Nicotiana species and varieties. In that part of the contribution concerned with somatic correlations the author deals with a cross between the varieties virginica. and macrophylla of the species Nicotiana tabacum. F; seeds were divided arbitrarily into the classes light, medium, and heavy. The light and medium seeds germinated more quickly than the heavy seeds, and plants resulting from the former matured more quickly than those from the latter. It does not appear, however, that the general belief that heavy seed gives more vigorous plants than light seed is incorrect. oreover, the total germination of heavy seed was higher than that of the other two classes. The author continually speaks of the dominance of one plant over another, a mediaeval mode of expression that makes it impossible to draw any conclu- sions from his observations on his F, generation. Likewise he finds that the heavy seed gave, in F,, 39 per cent of “dominants” (resembling macrophylla), r cent of intermediates, and 9 per cent of “recessives’’ (resembling ing results it is not surprising that he invents a theory for their interpretation that will no doubt be very interesting to cytologists, for in it he assumes that the “tube nucleus” of the pollen grain unites with the fusion “endosperm” nucleus of the embryo sac. He assumes that there are two “‘determiners,” one functioning to produce virginica characters and the other macrophylla characters. The generative nucleus, he says, may bear either, and the “tube nucleus” may bear either. The same alternatives are assumed for the egg nucleus and the fusion ‘“endosperm’”’ nucleus. Then, simply by having a macrophylla generative nucleus unite with a macrophylla egg nucleus, and a macrophylia ‘tube nucleus”’ unite with a macrophylla fusion nucleus, he gets a heavy seed having macrophylla characters. Quod erat demonstrandum. Chari- tably granting that the words ‘“‘tube nucleus” were slips of the pen, there is no excuse for founding a theory that the two male nuclei carry different ‘“deter- miners” upon unsupported data of this character. In the second part of his work, the author has studied the degree of domi- nance and the variation in size of corolla diameter in the parents and F, genera- tion of crosses between varieties of Nicotiana acuminata. The corolla breadth of the F, generation was found to be the arithmetical mean of the two parents. The fluctuation in corolla breadth, both in individual plants and in the popula- tion as a whole, was greater in F, than in the parents. These conclusions, at least as to the degree of variability of the F, generation, are at variance with the results of several careful investigators (the reviewer can count twelve such offhand), but it is impossible to criticize GoopsprEp’s data, for he does not give them in the form of frequency distributions. He simply reports maximum and minimum measurements, which may or may not mean anything. » 1913] CURRENT LITERATURE 407 He does indeed give two plates of frequency polygons, but his distributions are for number of flowers measured on particular dates, with no statement as to their size, and for relative frequency of flowers of certain sizes, with no data on the actual number of flowers measured or the number of plants upon which they were borne. Apparently the parents upon which data were taken were too few to warrant such sweeping conclusions. In the second paper, also, one gathers that the F, generation there reported on is more variable than the F, generation; but no data are recorded. This paper purports only to be a note, however, and one may expect some data of greater consequence when the really sid amount of work that the writer has done is reported in full—E. M. Eas Knot disease of citrus trees.—Herpcrs and TENNY? give a complete account of a knot disease of citrus trees that had been briefly described in a preliminary account by Miss Hepces.” The disease has been found on lime trees in Jamaica and in one instance in Florida. It manifests itself by woody knots or swellings which appear on the branches and trunks of the diseased trees. The knots are usually round or somewhat elongated in the direction of the axis of the branch which bears them. They attain a diameter of 2-3 inches, and by their growth usually girdle the branch upon which they are seated, this causing the death of all the parts of the branch above the knot. Groups of fascicled branches, forming witches-brooms, often grow out from the knots, but these branches also are short-lived. The knots consist mostly of woody tissue, at first covered by bark which soon dies and crumbles away. All the tissues of the knots, as well as the tissues of the branches near the knots, are found to be infected with the brown mycelium of a fungus which was described by Miss Hepcrs as Sphaeropsis tumefaciens. The mycelium of this parasite has been observed to spread to a distance of 45 cm., and it seems probable that it can spread to greater distances. Secondary knots are pro- duced by the mycelium which spreads through the branches. The growth of the fungus on a large number of media, its characteristics, and numerous infection experiments are described at length by the authors.—H. HasseEt- BRING The cause of leaf asymmetry.—Bosnart, working in GOEBEL’s labora- tory, reports the results of certain observations and experiments on asymmetry and anisophylly.* He concludes that the size of any given leaf part is deter- mined by the area it occupies in the vegetative point. Further development 9Hences, F., and Tenny, L. S., A knot of citrus trees caused by Sphaeropsis insuaficdaal Bur. Pl. Ind. Bull. 247. pp. 9-74. pls. 10. figs. 8. 1912. *” HEDGES, FLORENCE, Sphaeropsis rascetgy nov, sp., the cause of the lime and orange knot. pmo 1263-65. pl. I ™ Boswart, K., Beitrige zur ack a Blattasymmetrie und Exotrophie. Flora sé teccee Igtt. 408 BOTANICAL GAZETTE [MAY depends on nutrition, a poor food supply causing but slight enlargement of the part, whereas a good food supply causes considerable enlargement. The vegetative point, on the other hand, is unrelated to nutrition, so far as its symmetry is concerned. Contrary to most previous investigators, BOSHART finds no evidence that gravity or light influences leaf symmetry. It is believed rather that both anisophylly and leaf asymmetry are merely an expression of the symmetry of the plant as a whole. For example, anisophylly, and in most instances asymmetry also, is associated with dorsiventrality, radial shoots being characterized commonly by isophylly and symmetry. It seems very doubtful if this radical view, giving little or no place to the operation of external factors, will displace the many experimental contributions of past years. Even in this contribution it is admitted that good nutrition can result in the development of the vegetative point of a dorsiventral shoot into a radial shoot. It would seem, then, according to BosHart, that external factors determine what sort of a shoot develops, but that the type of leaf is tied up inexorably with a particular kind of shoot.—HENry C. CowLes. Photometric leaves and shoots.—WIEsNER in continuing his already very extensive studies upon the light relations of plants returns to the consider- ation of the orientation of leaves in response to the direction of incident light. Fixed and variable positions” are distinguished and examples of the latter, which he regards as the more perfect response, are multiplied, the legumes furnishing the major portion. More exact studies are made of leaves only apparently related to light and termed pseudophotometric,*3 in contrast to those actually orienting themselves in response to incident light, and emphasis is laid upon the part played by epinasty and geotropism acting before and simultaneously with phototropism. Most photometric — are found to be pseudophotometric in the earlier stages of their developme Relations similar to those existing in leaves are shown to a for shoots."4 All shoots with photometric leaves are shown to be themselves photometric, but the category also includes the shoots of such conifers as Abies and Tsuga, ons leaves showing very slight responses to light. The effect of light of ent intensities is to be seen in the shoots of Taxus baccata, being per- ede that is showing euphotometry, while with more intense light they become panphotometric. Some interesting cases of the photometry of ani- sophyllous shoots are also discussed.—Gro. D. FULLER. ” WiesNER, J. v., Uber fixe und variable Lichtlage der Blatter. Ber. Deutsch. Bot. Gesells. 29: 304-307. 1911. 33 WIESNER, J. v., Uber aphotometrische, photometrische, und pseudophoto- metrische Blatter. Ber. Deutsch. Bot. Gesells. 29:355-361. 1911. %4 WiESNER, J. v., Uber die Photometrie von Laubsprossen und Laubsprossys- temen. Flora 105:127-143. 1913. Volume LV Wumber 6 . THE BoTANICAL GAZETTE Editor: JOHN M. COULTER June I91r3 Toxic Inorganic Salts and Acids as Affecting Plant Growth Chas. B. Lipman and Frank H. Wilson The Transpiration of Apple Leaves Infected with Gymno- sporangium Howard S. Reed and J. S. Cooley Undescribed Plants from Guatemala and Other Central American Republics. XXXVI John Donnell Smith Vegetative Reproduction in an Ephedra W. J. G. Land Protoplasmic Contractions Resembling Plasmolysis Which Are Caused by Pure Distilled Water W. J. V. Osterhout Reproduction by Layering in the Black Spruce George D. Fuller Briefer Articles Thomas How Huron H. Smith The Secditie. a Phyllocarpus T. D. A. Cockerell Current Literature - The University of Chicago Press CHICAGO, ILLINOIS, U.S.A. Agents THE CAMBRIDGE UNIVERSITY PRESS, London and Edinburgh M WESLEY & SON, London : TH. STAUFFER, Leipzig THE MARUZEN-KABUSHIKLKAISHA, Tokyo, Osaka, Kyote Che Botanical Gazette A Monthly Fournal Embracing all Departments of Botanical Science Edited. by. JoHN. M. CouLter, with the alata of ise members of the botanical] staff of the y of Chic se fe 16, soe ‘ Vol. LV ae CONTENTS FOR JUNE 1913 No. 6 : Posie INORGANIC SALTS AND BET AS AFFECTING. PRANE GROWTH. Chas. B Lipman and Frank H. Wilso - THE TRANSPIRATION OF APPL LEAVES INFECT ws he abe? ee USER ae - (WITH ONE FIGURE). Howar , ad S. Reed and J. S. Coo 421 UNDESCRIBED PLANTS FROM GUATEMALA euiee OTHER Same yer isis AMER AM EPUBLICS.* XXXVI. John Donnell Smith. - 43 Vrcenarive REPRODUCTION IN AN EPHEDRA. ContRipurioNS FROM THE Hutt _ BoranrcaL LABORATORY 172 (WITH FIVE FIGURES). W. J. G. Land - 439 Sain aaa CONTRACTIONS RESEMBLING PLASMOLYSIS WHICH ne whip tee BY PURE DISTILLED WATER (wir six ricures). W. J. V. Osterhou 446 REPRODUCTION: BY LAYERING IN. THE BLACK SPRUCE. CONTRIBUTIONS: FROM THE Hutt BoTanicaL vias sierra 173 (WITH SIX FIGURES). George D. Fuller 452 BRIBFER ARTICLES | . HOWELL (wits PORTRAIT). Huron H.: Smith - = ne eS eae ee rae: DLING OF PHYLLOCARPUS (WITH ONE FIGURE). T. D. A. Cockerell - - = 2 460 Ee CURRENT LITERATURE MINOR NOTICES Et at Me a a Sh i eR Ge fe Snare Sis STUDENTS ae S vs ii 4 “a lo = a ol es et rf 463 ' Gazette is published. anil y [The subscription price is $7.00 per year; the price of single copies ca ae mts. Orders for service of less than a half-year will be char ag at the single- opy rate. ‘| Postage is ‘paebeie by the res apes on - orders from the United States, Mexico, Cuba, orto Rico, enecite anal Zone, Republic of Panama, Hawaiian eager Se. 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Til ons are Soipridir without cost to author only mite suitable originals are supplied. A copy se. 8 the suggestions made in the January number, 1907, will be sent on — ion. ioe is advisable to a confer with the editors as 5 illustrations required in any article to be offer — it aeiazerd must be ordered in advance of publication. or arates of original articles withiout e0 ers will be supplied gratis. A table showing af rae cos eof ibe scan is printe 90n an onder Cs fiche dearmeniard the aaa a copy will be sent matt hie aiaee March 5 ss. - VOLUME LV NUMBER 6 THE BOTANICAL GAZETTE FUNE 1913 TOXIC INORGANIC SALTS AND ACIDS AS AFFECTING PLANT GROWTH (PRELIMINARY COMMUNICATION) CuHas. B. LIPMAN AND FRANK H. WILSON The economic and industrial phases of the smelter fume and smelter waste problem, especially as related to crop growing in the vicinity of smelters, have been accompanied by a revival of interest In the scientific aspects connected with the physiological effects of the metallic compounds of copper, lead, zinc, and others on plant _ growth. There have appeared in 1905, 1908, and 1910, respectively, Bulletins 89, 113, and 113 revised, of the Bureau of Chemistry of _ Zanese in soils and its effects on plants, that led the authors to _ institute the preliminary experiments which are described below. . Before reporting these, however, it is of interest to turn for a _ Moment to a brief review of the results thus far obtained by plant 410 BOTANICAL GAZETTE [JUNE physiologists and chemists bearing on the subject under considera- tion. The extreme toxicity of copper to plants under certain condi- tions has been responsible, it would appear, for some assumptions on the part of investigators as to the similarity in the action of copper in solutions and in soils. Thus JoHNsoN, in his now classic work How crops grow, evidently assumes from the results obtained in solutions that copper is poisonous to plants even in very small quantities. Likewise the work of HEALD’ and Harter’ with plants grown in solutions shows copper to be extremely toxic to plants. The former found, for example, that 1 part of copper in 404,423 parts of water was deadly to the garden pea (Pisum sativum), and that maize (Zea mays) seedlings are killed by the presence of 1 part of copper in 808,846 parts of water. OsTERHOUT* showed how water obtained from copper stills was poisonous to certain of the lower plants when containing merely traces of copper, and Haywoop, in the work above mentioned, states that in preliminary work with plants in soils containing copper, the growth of wheat and rye is “interfered with by the presence of 2.1 parts of soluble copper per million parts of earth in one soil, and by 3.5 parts of soluble: copper per million parts of earth in another soil.” Some striking results on the effects of copper on plant growth which date back much farther than the last discussed were those obtained at the New York‘ and the Iowa’ Experiment stations. It is a curious coincidence that both of these investigations were reported in the same year (1892), and they were both the result of the fungicide investigations in which it appeared of interest to ascertain how the continued use of fungicides would affect the soil in its productive capacity. In the New York bulletin, Part I of which is devoted to the subject in question, we find that among peas, wheat, and tomatoes, which formed the test plants, a resistance was noted to as much as 2 per cent and 5 per cent of CuSO, of the t Bot. Gaz. 222125. 1896. 2 Bur. Pl. Ind., U.S. Dept. Agric. Bull. 79. p. 40. 3 Bor. Gaz. 44:272 (footnote). 1907. 4N.Y. Exp. Sta. Bull. 41. 1892. 5 Iowa Exp. Sta. Bull. 16, 1892. 1913] LIPMAN & WILSON—TOXIC SALTS AND ACIDS 411 dry weight of the soil, and while the soils free from copper gave much larger yields of fruit and vine than did those grown in soils containing copper, it is amazing to note such extreme resistance to large quantities of a poisonous compound on the part of plants as manifested by more or less growth. The author of the paper gives the results only as preliminary and promises a much more thorough review of the investigations later. Twenty years have passed since, however, and we are unable to find any further pub- lished data from the New York Experiment Station on that subject. One more note in the paper is of interest, and that is of a con- temporary paper by Hasetuorr,® the conclusions of which are quoted, in which that author states among other things that soluble copper salts are injurious to plants, and that while concentrations up to 5 ppm. are harmless, the presence of 10 ppm. of copper in soil has a marked retarding action. In the Iowa bulletin by Pam- MEL we find that copper solutions had a marked retarding effect on the root development of plants, and that no roots at all developed where the concentration of copper was large. It is unfortunate that PaAmMMEL does not make mention of the concentrations of copper existing in the various experimental plots in the greenhouse. So far as the effect of zinc salts on plant growth is concerned, there is but meager information. We have, however, the recent investigations in Germany on the effect of the zinc in galvanized iron cylinders, used for vegetation experiments, on plant growth. From these it would appear that zinc may be distinctly toxic to plant growth. agg cee 5 with manganese, however, have been very numer- ; but their results have been so conflicting as to make more ia work very desirable. The reader is referred for a more complete bibliography on the effects of manganese in soils on plant growth to a recent publication by W. P. KELLEY.’ Along with the problems of smelter fumes and smelter wastes, has come the idea of the condensation of the sulphur dioxide and the manufacture of H,SO,. It has been calculated by Corrrett and others, however, who have made a careful study of the problems, ° Landw. Jahrb. 21: 263. ? Hawaii Exp. Sta. Bull. 26. 412 BOTANICAL GAZETTE [JUNE that the amounts of H,SO, thus produced would be so enormous as to make it useless, since the demand for the acid is as yet quite limited. It has been suggested, therefore, among many other proposed uses for it, that H,SO, be used in small quantities in the irrigation water to act as a solvent for soil minerals. It was this idea which suggested the preliminary experiment described below, along with the others, on the effects of the metallic salts on plant growth. ' Experiments The soil employed in the experiments was a light sand with a good humus supply, and was constituted chemically as follows: Insoluble residue. ...... ee tp er cent MnO... ci. sei... ©.o1 per cent os ee ae 2.94 [5 Re ae 0. 26 RAE grag ae ogres eee 2.05 0.36 Re see: 3.38 1) See aera ae 0.17 eS es 1.59 ee ia as 0.45 Bes ee ook oes s 0.02 we. pees 2.35 Large 8-inch flower pots were filled with 12 lbs. of soil and treated with varying amounts of the solution of the salt to be tested, each cc. representing a known weight of the salt. The con- centrations employed are noted in the tables in parts per million of water free soil. The plants tested were the vetch (Vicia sativa) and the Little Club variety of wheat. Eight seeds, which were carefully selected, were planted in each pot, and after some growth was made were thinned to 4 plants per pot. The pots were care- fully irrigated so as to give the soil an optimum moisture content but not allow any moisture to percolate from the soil, thus prevent- ing loss of the salts tested. The plants were all grown under glass and appeared to make good vigorous growth from the start. The appearance of the aphis and other insects in large numbers undoubt- edly had something to do with diminishing the total yield of dry matter, but not enough to affect the results seriously. The vetch was not allowed to mature, but had to be harvested about the same time that the wheat was cut, because the mildew had attacked the plants rather seriously. The wheat was mature, however, when harvested. In the case of the vetch, the weight of the tops, as well as that of the roots, is given, while in the case of the wheat, only the 1913] LIPMAN & WILSON—TOXIC SALTS AND ACIDS 413 weight of the tops as dry matter is recorded. The following tables give all other explanatory data and results of the experiments, and a discussion follows each table. TABLE I Errects or CuSO, ON PLANTS D GHT O DRY WEIGHT OF VETCH oe CuSO, ppm. Roots gm. Tops gm. Tops gm. Oe ole a 4-5 I2.0 18.5 SH BPR ra oares ranma cay MAUL Dara Sr 1.8 20.5 CG: BOG eae Pee oe eae 5:5 20.0 16.2 SO oe hae Lee ne eis 4.0 aIr.0 17-5 BO es ha oe ee 5.5 17-5 13.90 NOD. cs UE Soe See ae ee 3.0 18.0 16.5 oie ke eg oe ean ae ees 4-5 14.0 17-2 BOO Ss oo teste ae ee Det. lost 12.0 19.0 ee ee bus ae 42.7 IO: cons va Geir fae Wie ay oe 5 13.0 9-7 To one accustomed to regard CuSO, as an extremely poisonous salt for plants, the data in table I offer a surprise. While it is true that in the case of the wheat no stimulation from CuSO, is evident, its toxic nature likewise cannot be said to manifest itself until a concentration of 1000 ppm. is reached, if then. The last phrase is used advisedly, since the plants in the 600 and 1000 ppm. concentrations of CuSO, were started three weeks later than the rest. Germination of the wheat seeds seemed to proceed with much greater rapidity in the higher concentrations, but the plants though growing fast did not seem to possess the deep green color which is so characteristic of plants well nourished. These plants, however, matured at about the same time as the other wheat plants growing in the lower concentrations of CuSQ,, and produced normal eads. In the case of the vetch plants, there seems to have been a stimulation due to CuSO,, and then what might perhaps be looked upon as toxicity in the highest concentrations. It should be noted, however, that here, as in the case of the wheat, the vetch plants growing in the higher concentrations of copper were planted three weeks later than those growing in the soils with lower concentrations 414 BOTANICAL GAZETTE [JUNE of copper. It is especially interesting here to mention the rapid and rank growth made by the vetch plants in the highest concen- tration of copper. All the seeds germinated and the vetch plants seemed to grow erect to a height of 6 inches or more before they began to bend downward by their own weight. The plants in the normal soil and in those with low concentrations of copper made but very little upright growth. One further point is of great interest in regard to the vetch plants, and that is that even at the highest concentrations of copper, the root development appeared to be normal and showed a marked and vigorous development of nodules (the soils were all inoculated). In general the effects of the copper sulphate as given in table I stand out in sharp contrast with the results above reviewed. They exhibit, on the one hand, a very much greater resistance to the effects of copper on the part of both wheat and the vetch plants than Haywoop observed in the case of wheat and rye as above noted; and on the other hand, our observa- tions on the plants growing in the highest concentrations of copper given in table I lead us to believe that they will not withstand amounts of copper at all to be compared with those tolerated by the plants with which the experiments at the New York Experiment Station were carried out. From our results it would appear that the use of irrigation water containing a few parts of copper per million would not for many years react deleteriously to plant growth, while the very reverse is believed by Haywoop on the basis of his results. Further results were promised by Haywoop in 1908 based on his experiments with soils, but none have as yet appeared. With reference to the cause of the injurious action of copper there are two explanations. One shows that there is direct injury due to absorption of copper as manifested by analysis, and fre- quently showing a large quantity of copper in plants sprayed with fungicides or in those growing in soils with a high copper content. HAsELHOFF, however, whose work is cited above, claims that his investigations indicate an increased solution of lime and potash and subsequent leaching away of these materials through the action of copper sulphate, and that injury can be averted by applications of CaCO, to replace the losses taking place as indicated. 1913] LIPMAN & WILSON—TOXIC SALTS AND -ACIDS 415 The next series deals with the effects of ZnSO, on plants. The experiment was arranged similarly to the preceding, but the con- centrations are slightly different, as shown in table II. TABLE II EFFEcts oF ZNSO, ON PLANTS DRY WEIGHT OF VETCH a sg ZnSO, ppm. Roots gm. Tops gm. Tops gm. FPR Re urge Hee Se FR Acs 2.0 18.5 IOs Suc eee ee eg £5 12.5 $9.5 BOs es 8s ee ee eee re 20.0 18.5 TOO go ai oe oe 4.5 22.0 18.5 ROO a Sc ee eee 45 20.0 14.6 3008 5 iS eee er rere 2.0 20.0 10.8 BOO a les ec ga 1.8 18.0 19.8 BOO er eee 1.5 15-5 13.7 These results do not show any marked toxicity of ZnSO, either for the vetch or the wheat. In the case of the vetch, there would even seem to be an appreciable degree of stimulation up to rather large concentrations of zinc. We can certainly not confirm any toxic effects of zinc salts on plants observed by others, at any rate so far as the concentrations employed above are concerned. The seeds germinated in the zinc-treated soils in a normal manner, and the plants in all the concentrations of the ZnSO, seemed to make a normal growth. Whatever differences may be noted in table II between the growths made in the pots of the different concentra- tions of salt employed must be attributed to insect or fungus injury rather than to any effect of the ZnSO,. A comparison of our results with the effects of zinc noted by EHRENBERG, whose work is above cited, would seem to indicate that the later investigations® attribute both favorable and unfavorable effects to the zinc dissolved out from the galvanized iron cylinders used in the vegetation experiments. EHRENBERG Claims that zinc acts favorably in that it displaces the bases from their insoluble combinations, and because of its harmful effect on soil organisms makes less competition for the plant in the latter’s search for soil nitrogen. On the other hand, the same author points out that zinc sets free hydroxyl ions which exercise § Landw. Versuchs. 72:15. 1910. 416 BOTANICAL GAZETTE [JUNE a corrosive effect on plants, and that a too rapid displacement of bases in the soil and their subsequent leaching tends to cause soil acidity. It is to be regretted that EHRENBERG’S researches were carried out from the point of view merely of establishing the feasibility of employing vegetation cylinders containing zinc, and therefore we have nothing to guide us to the extent of the solution of zinc and the toxic limit thereof. It appears to us, further, that it is begging the question to assert that the toxic effect of zinc on soil organisms is of benefit to plants for the reason mentioned, because we have no definite data concerning the effects of zinc on soil bacteria or other soil organisms, and certainly not evidence enough, so far, to point to wide differences between the effects of zinc on the higher plants and soil bacteria. From the data in table II, at any rate, it would appear that plants will tolerate and will not be affected by even very considerable quantities of zinc. In connection with this series of experiments in particular, it is desirable to have more experimental data, which we are attempting to secure in further experiments now under way. The numerous and conflicting results obtained by different investigators in the study of the physiological effects of manganese salts on plants made it desirable to work further with these inter- esting compounds, and an experiment was arranged, therefore, in which this problem could be studied. The arrangement of the experiment with the results obtained are given in table III. TABLE III Errects oF MNnSO, oN PLANTS DRY WEIGHT OF VETCH _ Day WEIGHT oF MnSO, ppm. ‘ces iE Roots gm. Tops gm. Tops gm. Oo ae 4-5 12.0 18.5 WO. Por Ce 4.0 9-5 16.2 BO 4.5 8 lo 20.0 BO pi Sah ie de ee VS 6.0 15.0 yes We ROSS ey tak Ce ie 4.0 18.0 25.1 8 Pe Ps a oa aera een Poe loa 5.0 sy a3.2 OG ie os hs a vt 5.5 19.5 26.0 GO ee i a a a8 10.0 g2.5 1913] LIPMAN & WILSON—TOXIC SALTS AND ACIDS 417 It is clear from the data given in table III that both wheat and vetch are stimulated by the presence in the soil of MnSO, until the concentration of the latter there reaches an equivalent of 2000 ppm. for the wheat, and 800 ppm. for the vetch. Indeed, the total yields of dry matter obtained from the wheat growing in the pots with the highest concentrations of MnSO, surpass quite markedly the yields obtained in any of the pots of the other series described in this paper, and which were planted contemporaneously with the former. In the case of the vetch, the stimulation does not seem to be as great as in the case of the wheat, but from one series of experi- ments it is difficult to say if stimulation actually stops for the vetch at a concentration of 2000 ppm. of MnSO,, since the poor growth obtained there may have been due to experimental error. These results are an interesting contribution to the subject of the effects of manganese salts on plants. It is not our intention here to discuss the large number of investigations bearing on this subject, especially since this has already been so well done by LLEY, in the work above referred to. In general, however, it would appear from such a review that the largest number of investigations on the subject indicate a stimulating power of man- ganese sulphate for plants, results with which ours are in accord. There are several cases, however, in which manganese compounds have been observed to depress crop yields, and this point would seem particularly to deserve brief discussion. The experiments dealing with this subject which have thus far been carried out have included tests of many different manganese compounds, and a com- parison of the results obtained with different compounds in trying to determine the specific effects of manganese would seem to us to be manifestly unfair. One of us has pointed out elsewhere? that the anion as well as the kation of salts must be taken into considera- tion when the effects of salts on living organisms are studied. such be the case, and we have every reason to believe that it is, then only the experiments bearing on the effects of MnSO, on plants should be compared when that subject is studied, and not the effects of the nitrate, chloride, oxide, sulphate, and other compounds. When that is done, it will be found that the percentage of investi- 9 Centr. Bakt. 33:305. 418 BOTANICAL GAZETTE [JUNE gations dealing with the subject under discussion in which MnSO, has not been found, in relatively small quantities, to act as a stimulant is indeed very small. Obviously when very large con- centrations of MnSO, are employed it will be found toxic. As investigations of KELLEY above referred to have shown, a large variety of plants is affected more or less seriously by the manganese of soils which have shown a content of that material equivalent in some cases to more than g per cent of Mn,O, in the soil. However, such manganiferous soils are limited in extent and, undoubtedly even then, owe their unfavorable nature, in part, to the form of the manganese which they contain. This point appears to us so important as to render a comparison of past results on manganese investigations of little value when it is not considered. It would seem from our results in this series of experiments, and others of a similar nature which they help to confirm, that distinct increases in crop yields of certain plants may be induced by employing MnSO, in small quantities as a soil amendment. The manganese content of most ‘“‘normal’’” soils is very small, and therefore the dangers aris- ing from the presence of large amounts of manganese, as KELLEY has observed them on certain Hawaiian soils, are certainly very remote ones when considered in relation to these normal soils. Small additions of manganese should increase yields, therefore, without introducing dangers. We hope to report further results on this subject later. As was pointed out above, it has been suggested by some chemists, among the many other uses proposed for H,SO, when it is produced in enormous quantities from the SO, of the smelter fumes, that it could be employed in small quantities in the irriga- tion water, and, through the solution of mineral plant foods in the soil, be a considerable aid to the nutrition of plants directly, besides exerting perhaps a very marked influence indirectly on soil fertility as will be discussed later. In connection with soils containing black alkali, sulphuric acid would have an added value, if it were satisfactory in other ways, in that it would change the black to the white alkali more cheaply than gypsum does, and it could be applied more easily with irrigation water. Indeed, it is possible that in soils with a content of Na,CO,, not too large, the sulphuric 10 Soils ordinarily cropped. 1913] LIPMAN & WILSON—TOXIC SALTS AND ACIDS 419 acid treatment of soil may prove a valuable practice. The follow- ing experiment was considered, therefore, of very great interest as a preliminary test of the physiological effect of H.SO, on plants, and its arrangement and results are set forth in table IV. TABLE IV Errects oF H,SO, ON PLANTS DRY WEIGHT OF VETCH Dry WEIGHT OF WHEAT H.SO, ppm. Roots gm. Tops gm. Tops gm. OSs es ee ee 4:5 17:6 18.50 SOu. ce ee ee Sis 15.0 12.20 BOO os ek en ce ee ee 6.0 1g-5 16.65 200 Oo es Pen ea 2.5 8.0 18.50 BOO oo teers ee Oe eee 4.0 19.5 20.50 BOO So So als Sere en 4.0 17.0 T0.50 O00 ideo ee) oman eee ee 5.0 15.5 26.20 The foregoing data would seem to indicate that considerable amounts of H,SO, may be added to soils without injury to plants. The objection, of course, to which such additions of acid would be open to in practice, is that when the lime and other bases have been neutralized in the soil by the acid, any further additions to the latter would tend to make an acid soil which is unfavorable for plant growth, but it is at any rate safe to assume that on strongly alkaline soils, where that condition is the interfering fact with plant growth, the acid treatment of soil should ameliorate its unfavor- able condition to a marked degree. Moreover, we are not without a basis in fact for our assumption. SymMMonpDs™ has shown that when nitric acid to the extent of 600 pounds per acre was mix with artesian water and applied to soils containing alkali, the yields of crops were greatly increased. It may be argued, of course, that this case is not an analogous one, since the nitric acid combines with bases in the soil to form nitrates which are an important food and even stimulant to plant growth, but it should also be remem- bered that, as one of us has already pointed out elsewhere, in a publi- cation above cited, on the basis of direct investigations, that Na,SO,, produced through the action of H,SO, on Na,CO, (black alkali), is a stimulant to nitrification, and that thus an application of 1 Agric. Gaz. N.S. Wales 21:257~266. 420 BOTANICAL GAZETTE [JUNE H,SO, to soils would render a service to the plant different in de- gree only but not in kind from that rendered by the application of HNO. General remarks While we offer the results given above as a preliminary report merely, on a series of investigations which we trust will ultimately make a thorough survey of the subject, we must conclude from these data that the tolerance of plants for certain of the inorganic salts, commonly regarded as very poisonous, is much greater than we have been wont to believe. It is true that we have commonly accepted the idea that very small quantities of poisons may act as stimulants, but our results show that plants do not merely tolerate but are actually stimulated by quite considerable quantities of these toxic salts. It is very desirable, therefore, to arrive at a definite under- standing of the limits of toxicity of the substances in question, which we are now endeavoring to do. It would appear to us, further, that the results we have obtained are sufficient evidence to prove that a more thorough investigation into the effects of smelter wastes on plants is necessary before we are enabled to determine justly whether from that standpoint smelter plants are inflicting appreciable injury on the soils imme- diately surrounding them and on the soils of contiguous territory. Our results on the effects of MnSO, are considered of importance here both because of the stimulating effect of the former on plants and the attempts which have been made to make use of that fact in the employment of manganese salts as fertilizers. Moreover, our data form another link in the chain of evidence which show the stimulating effects of manganese sulphate on plants. It may not be amiss to add here, also, that to make these investi- gations more complete we have been making studies of the bacterial flora in the soils employed in the experiments above described. From these we have already obtained data of great interest, which seem to indicate that the soil flora is permanently modified by the treatment of the soil outlined above. The publication of these results is reserved for another paper. Sorts RESEARCH LABORATORY UNIVERSITY OF CALIFORNIA THE bagireaa etry OF APPLE pombe INFECTED WITH GYMNOSPORANGIUM Howarp S. REED AND J. S. CooLey (WITH ONE FIGURE) The present paper reports the results of some studies upon the transpiration of apple leaves infected with the cedar rust fungus, Gymnosporangium Juniperi-virginianae Schw. Observation of trees attacked by this fungus shows that changes involving serious injury to the economy of the trees are produced. Such trees usually show characteristic dwarfing of both trunk and fruit. The writers have undertaken to make some quantitative physiological studies upon these diseased trees as a part of a general pathological problem. The study of the causative organism is highly important for plant pathology if any prophylactic measures are to be taken, but the reaction of the host is also a factor of importance if thé action of the parasite is to be understood, or if efficient remedial measures are to be applied. The interest of the cultivator is principally in the host, but up to the present time that of the plant pathologist has been chiefly centered in the parasite. It is believed, however, that a physiological-pathological study of the host -will yield results of no less interest than those of a strictly mycological nature. A survey of the published work upon transpiration discloses few studies of the transpiration of diseased plants, although the assumption is frequently made that the rate of transpiration is affected by the presence of disease. BLopDGEtT? has reported an observation upon the transpiration of excised branches of Rubus sp. infected with Gymnoconia inter- stitialis. In a given period (apparently shorter than 24 hours) the rusted branch absorbed 42 cc. of water, while a healthy branch possessing an equal number of leaves absorbed only 23 cc. of water t Paper 24 from the Laboratory of Plant Pathology, Virginia Agricultural Experi- ment Station. 2 BLopcett, F. H., Transpiration of rust-infected Rubus. Torreya 1:32. 1901. 421] . {Botanical Gazette, vol. 55 422 BOTANICAL GAZETTE [JUNE under similar conditions. In spite of the greater amount of water absorbed, the rusted shoot was more or less flaccid, while the healthy shoot maintained a turgid condition. This behavior might be regarded as a consequence of the condition produced by the caeoma type of sorus produced by the fungus in question. The rupture of more or less extensive areas of the ventral epidermis of the leaf obviously facilitates the evaporation from the spongy parenchyma layers. Possibly other factors connected with the diseased condition may also operate to cause increased transpiration. While not strictly parallel, it may be proper in this connection to cite results which BuRGERSTEIN’ obtained with the use of dilute solutions of camphor. He found that solutions containing about one part of camphor per thousand had an accelerating influence upon most plants investigated. Excised shoots, which were pre- viously allowed to become somewhat wilted, revived more quickly when placed in camphor water than when placed in distilled water. By weighing the vessels of water in the two cases, it was shown that transpiration from the shoots went on more rapidly in camphor water than in distilled water. That camphor was absorbed by the excised shoots was shown by their pathological condition and death prior to the appearance of any such conditions in the parallel series in distilled water. It seems proper to regard this result as an example of transpiration under pathological conditions, since the deleterious substances thrown off by fungi may act similarly to the camphor. Results of a somewhat similar import have been reported by one of the authors of this paper, showing that substances like tannic acid and pyrogallol when present in small amounts accelerate transpiration.4 Small amounts of oxalic and acetic acids were likewise shown to accelerate transpiration. Since these substances are found as such in plants, it is possible that they may influence transpiration more or less independently of other factors. The studies upon transpiration herein described were conducted 3 BURGERSTEIN A., Uber einige physiologische und pathologische Wirkungen des Kampfers auf die Pflanzen, inbesonders auf Laubesprosse. Verh. Kais. Kin. Zoolog.- Botan. Gesells. Wien 343543. 1884. 4 REED. H. S., The effect of certain chemical agents upon the transpiration and growth of wheat seedlings. Bor. Gaz. 49:81. 1910. 1913] REED & COOLEY—TRANSPIRATION 423 upon the apple varieties York Imperial and Ben Davis in orchards near Middletown, Virginia, in 1911 and 1912. All of the trees upon which studies were made were more than eight years old, and, aside from a certain amount of dwarfing due to continued attacks of cedar rust in one of the orchards, the trees were in good physiological condition. The time available for making satisfactory studies on transpira- tion of the diseased leaves was restricted to a period of about five weeks beginning near the middle of July. Before that date the cedar rust had not developed sufficiently to derange seriously, or at least uniformly, the activity of the apple leaves. Subsequent to this period, the fungus has injured or even killed more or less extensive areas in the infected leaves, and, in cases of severe infec- tion, the leaves begin falling during the latter part of August. The work here reported was carried out on leaves and twigs on the trees in their normal position. This method was believed to be preferable, since it has been shown by FREEMANS that actively transpiring shoots do not usually transpire at a normal rate when removed from their own roots. The data reported in the present paper were obtained by inclos- ing a few apple leaves in a glass cylinder and absorbing the exhaled water with weighed calcium chloride. The method of carrying on the experiments will be evident from the accompanying sketch of the apparatus (fig. 1), which is a type modified from that of FREEMAN (loc. cit.) and others. In its essentials the apparatus consisted of three parts: a wide mouth glass jar (A) which contained the twig under experimenta- tion, a calcium chloride tube (B), and an aspirator (C) which drew a known volume of air through the apparatus. The glass jar (A) was fitted with a soft rubber stopper which was cut through about three-fourths of its diameter. The opposing surfaces were notched at the center of the stopper to allow a twig to pass through, but the notch was small enough to insure a tight fit and prevent the passage of air. Two perforations in the stopper allowed glass tubes of 5 mm. diameter to pass. Tube 1, through which the air entered, extended to within 1 cm. of the bottom of the jar; tube 2, 5 FREEMAN, G. F., A method for the quantitative determination of transpiration in plants. Bor. Gaz. 46:118. 1908. 424 BOTANICAL GAZETTE [JUNE through which air left the jar, extended only about 1 cm. inside of the stopper. Tube 2 was connected with rubber tubing to a glass-stoppered calcium chloride tube (B). The calcium chloride tubes were accurately weighed at the laboratory before and after each experiment. The ground stoppers (3, 3), when turned, effectually closed the tubes. The aspirator for drawing air through the apparatus was a bottle of 19 liters capacity fitted with a siphon through which the flow \ = C CHCrobill Fic. 1.—Apparatus for measuring transpiration: explained in text could be regulated by means of a screw clamp (4). Three sets of apparatus were constructed and carried in a spring wagon which could be moved from tree to tree as occasion required. The manner of conducting an experiment was as follows. The apparatus was placed at a tree where direct rays of sunlight would not strike it. A twig bearing leaves suitable for experiment was selected and inserted in the cleft rubber stopper, precautions against bruising or injuring the bark being used. In some cases one or two leaves had to be removed from the twig in order to make a good adjustment. After a few trials it was found that not more 1913] REED & COOLEY—TRANSPIRATION 425 than two apple leaves could be used in an experiment with a moder- ate rate of aspiration; if more were used, water would sometimes collect in the jar A. A thermometer was inserted in the jar with the twig, or suspended close to it. The previously weighed U-tube was connected on one side with tube 2 and on the other with the aspirator C, which contained 19 liters of water. Care was taken that the temperature of the water used in the aspirator should be very close to that of the air. When the siphon was started, the stoppers (3, 3) were turned to allow air to flow through the appara- tus. The flow of water could be regulated by means of the screw clamp (4) after a little experience, so that the time required to | draw out 19 liters should be close to an hour. The first apparatus was set up with healthy leaves in the jar A; . another experiment was similarly set up with leaves infected with cedar rust; a third experiment was set up but with the omission of the jar A. These three, each with its own aspirator, were started as nearly simultaneously as possible, and the temperature kept uniform. The purpose of the third set of apparatus was to deter- mine the amount of moisture in 19 liters of air. The criticism might justly be made that the evaporating power of the atmosphere was not taken into strict account by this sort of an experiment. If the purpose had been to study the conditions or amount of transpiration, such determinations should have been made, but the purpose was to study the comparative transpiration of the healthy and diseased apple leaves, and as such it is believed to fulfil its purpose. Another possibility of error might be found in the vapor pressure from the water in C, which would carry back some moisture into the tube B and cause the results to be too large. This source of error, however, is obviated by the use of the blank, whose increase in weight was subtracted from each of the accom- panying tests. As soon as the aspirator ceased running, the glass stoppers of the U-tubes were closed and the time noted. The leaves were plucked from the twig, placed in a labeled envelope, and taken to the laboratory along with the set of U-tubes. After weighing the tubes and computing the gain in weight, the necessary correc- tion was made for the moisture absorbed from sources other than the leaves as registered by the increase in weight of the blank. 426 BOTANICAL GAZETTE [JUNE The outline of the leaves used was carefully traced on paper and the area measured with a planimeter. The results thus obtained were computed and expressed as grams of water transpired per hour per sq. cm. A sample record sheet is herewith given, showing the records as made in the field. TRANSPIRATION TEST NO. 2 TRANSPIRATION TEST NO. 3 July 13, 1912 July 13, 1912 Healthy York Imperial leaves Diseased York Imperial leaves Temperature... . : 20.5 C. aemperature.... age C No. of leaves in test. I No. of leaves in test. . I Area of leaves. :...... 21.3 sq.cm. ‘Area of leaves....... 35.2 sq. cm. Vol. of air used...... 19 liters Vol, of air ised . 3: 19 liters Exper’t began 10:18 A.M. Exper’t began....... 10:14 A.M Expert ended... .... 11:20 A.M. . t — ep eds 11:16 A.M eee 62 min. Seeeen. et ...f. 62 min. Final wt. of tube. .... O1.555 gm. etal wt. as tube... . 99.675 gm. Initial wt. of tube....91.185 gm. Initial wt. of tube... .99. 297 gm. Dierenee os ieee ck: 0.370 gm. AMTONE a 0.378 gm. Water in equiv. vol. Water in equiv. vol. Wie ah is oy es ©. 291 gm. oe ere ere . 291 gm Water from leaves.... 0.079 gm. Water from leaves.... 0.087 gm. heeds per hr. per sq. Water per hr. per sq. Peg a ee es 0.0036 gm, irc tie eas oO ees On. There were 52 determinations made upon healthy and diseased leaves of the York Imperial and 26 upon leaves of the Ben Davis. The results are presented in tabular form in tables I and II. An inspection of the tables shows that the unit transpiration of the diseased leaves of both varieties of apples was in the majority of cases less than that of the healthy, although exceptions are to be noted. Some of these discrepancies may have arisen from unguarded errors of ——— but it is not probable that all are due to such cause. It is not apparent that the ratio between the transpiration in the healthy and diseased leaves was subject to any regular hourly variation. The unit transpiration in each case naturally varied from hour to hour, but the ratios were in general the same at any given period of the day. The average ratio of transpiration in the diseased and healthy 1913] REED & COOLEY—TRANSPIRATION 427 TABLE I TRANSPIRATION OF DISEASED AND HEALTHY YORK LEAVES Transpiration | Transpiration cen Hour at which of healthy of diseased of water No. Date oe leaves in gm. leaves in gm nspi egan per hr. per r hr. pe dise: sq. cm. sq. cm. leaves I9gt2 iar Gy Cee July 9 3:27 P.M 0.00627 0.0064 103.6 phere. Marana 9 4:15 P.M 0.00257 0.00203 78.6 ecere lire asa bie) Q:10 AM 0.0022 0.0033 150.0 PE eee prone Bie) 10:20 A.M 0.0074 °. 93-2 GS Ai are wee 10 2:20 P.M 0.0039 0.0043 110.3 Ona it 10 3:50 P.M ©,0041 0.0040 97-5 sere Cee 12 9:30 A.M 0.0057 0.0005 II4.0 Las ee 12 10:45 A.M 0.0134 0.0071 52.9 co ed nner ara 12 2245 P.M 0.0046 0.0048 104.3 ROE ea coed 12 4:05 P.M 0.0079 0.0040 50.6 LT ee ay ee 13 9:03 AM 0.0083 0.0106 127.7 Tae ea es 13 10:14 AM 0.0036 0.0023 63.9 1 Ug aoe gy 13 1:38 P.M 0.00403 ©,.0043 106.7 DG cans fe 15 9:06 A.M 0.00508 0.0082 161.4 TS ee 15 10:07 A.M 0.0079 0.01033 130.7 TOS es 16 10:20 AM 0.0257 0.0095 36.9 petiolis racemis pubescsncilvus: Foliola plerumque 5-juga praeter costam g per paria deorsum decrescentia, supremis usque ad 8 cm. longis 3.§ em. latis, infimis circiter 3 cm. longis 2 cm. latis, petiolo communi 1-3. 5 cm. longo, stipulis linearibus 7 mm. longis deciduis, rhachi 8-12 cm. longa, petiolulis 1 mm. longis incrassatis. Racemi ad nodos defoliatos 1-4-ni subsessiles, rhachi 10-13 mm. longa, pedicellis 4-7-nis 11-15 mm. longis prope basin articulatis et ibidem bractectis 2 connatis lanceolatis 2 mm. longis instructis, floribus praeter calycem glabris. Sepala cartilaginea 9-11 mm. longa. Petala tenuiter membranacea, late- ralibus summo intimo bis fere majoribus, inferioribus minimis vel deficientibus. Vagina staminalis postice 12 mm. longa antice 9 mm. longa, filamentis 14-17 mm. longis, decimo summo libero 18 mm. longo, antheris 2-2. 5 mm. longis. Ovarium lineari-oblongum 5 mm. longum circiter 3-ovulatum, stylo 13 mm. longo, stigmate globoso. Legumen indehiscens 1-2-spermum, dispermum dum adsit usque ad 17 cm. longum 4.5 cm. latum, monospermum 12.5 cm. longum 4cm. latum, suturae ala 10-12 mm. lata. Semen ovale 2.5 cm. longum 1.5 cm. 434 BOTANICAL GAZETTE [JUNE latum, Tscsiaaal cageut 2.5 mm. longa.—Haec ab - specie hactenus unica hemi Americani incola differt inter alia foliolis paucioribus et uti flores majoribus. - rope Gualan, Depart. Zacapa, Guatemala, alt. too m., Febr. 1912, Wilmatte P. Cockerell; exemplum tantum floriferum in herbario Musei Natio- nalis sub numero proprio 1861342 servatur. De hac specie ita in literis scribit cl. repertor, domina oculatissima res novas acute cernens: Arbor usque ad 18—25-metralis ad ripas Rio Montagua et secus viam ferream haud rara floribus praecocibus coccineis odoratis speciosissima formicis apibus volucribus fre- quentissima ab incolis Guacomaya vocata.—Exempla foliifera et fructifera eodem loco Maj. 1912 legit E. Morris. Calyptrella cycliophylla Donn. Sm.—Folia suborbicularia deltoideo-cuspidata basi obtusa quinquenervia coriacea subtus glandulis punctulata. Flores breviter pedicellati ebracteolati hex- ameri. Calyx furfuraceus. Petala lanceolata attenuato-producta breviter unguiculata. Capsula nitida subovoidea 4—5-valvis. Ramuli fistulosi subtetragoni cum petiolis et panicula ferruginei fur- furacei vel glabrescentes. Folia glabra 19-22 cm. longa 15-17 cm. lata, cuspide 5 mm. longa obtusa, nervis transversis 6-12 mm. inter se distantibus, petiolo teretiusculo 6-8 cm. longo. Panicula deltoidea pedunculo 8 cm. longo griseo uraceis, floribus inapertis lanceolato-ovoideis 5.5 mm. longis, calyptra glabra apice nutante. Calyx subhemisphaericus 2 mm. altus 3 mm. latus 12-costatus. Petala 6 inaequalia 5 mm. longa satis asymmetrica late unguiculata obscure 6-nervia. Stamina 12, antheris 1.5—2 mm. longis filamenta subaequantibus. Ovarium calycem haud superans nitidum sulcatum, stylo 3. 5 mm. longo recto. Capsula nigra calyce bis longior 5 mm. longa 3 mm. crassa 4-5-angularis et-sulcata, valvis plerumque 4, seminibus filiformibus 2 mm. longis straminiis. ecus rivulum prope Buenos Aires, Comarca de Puntarenas, Costa Rica, alt. 280 m., Jan. 1892, Ad. Tonduz n. 4964.—Ad ripas fluminis La Unién dicti, Comarca de Puntarenas, Costa Rica, Jan. 1897, H. Pittier n. 10584. Gilibertia gonatopoda Donn. Sm.—Folia maxima elliptica obtuse cuspidata basi acuta vel obtusiuscula. Racemi terminales vel laterales, pedunculis crassis sulcatis paulo infra medium pluri- bracteolatis articulatis geniculatis ceterum nudis. Calyx turbina- tus petalis longior. Drupa globosa. Arbor mediocris, ramulis subteretibus sulcatis. Folia pergamentacea 11- 30 cm. longa 5-18 cm. lata integra, nervis lateralibus utrinsecus 9-10 subrectis 1913] SMITH—PLANTS FROM CENTRAL AMERICA 435 in utraque pagina — petiolis canaliculatis sulcatis 2-12 cm. lon, stipulis deciduis. Racemi floriferi rhachis 4-5 cm. longa, pedunculi beck circiter 2.5~3.5 cm. tania epidermate transversim rimulosi ad_ articula- tionem nodosam bracteolis 4-6 rotundatis 1 mm. altis circumdati, recepta- culum parce minuteque bracteolatum, pedicelli 25-40 circiter 8-11 mm. longi, flores pentameri 4.5-5 mm. longi. Calyx 2.5~3 mm. longus 2 mm. latus margine subinteger. Petala subcarnosa ovata 2 mm. longa acuta 1-nervia staminibus subaequilonga. Discus hemisphaericus 1. 5 mm. -diametralis. diametrales columna stylari'1 mm. longa disci dimidium aequante coronatae. “Ad ripas fluminis Turrialba dicti, Prov. Cartago, Costa Rica, alt. 500 m., Mart. 1894, John Donnell Smith n. 4829 ex Pl. Guat. etc. quas ed. Donn. oe —Mn silvis prope flumen Zhorquin dictum, Talamanca, Costa Rica, alt. 200 m., Mart. 1894, A. Tonduz n. 8512.—In silvis ad Shirores, Talamanca, Costa Rica, alt. 100 m., Febr. 1895, A. Tonduz n. 9323.—In silvis apud Tsaki, Rig, Costa Ris, alt. 200 m., Apr. 1895, A. Tonduz n. 9587.—Ad marginem flum Del Convento dicti, in valle Diquis, Comarca de Puntarenas, Costa Rica, ae 1898, H. Pittier n. 12110. Secus fluvium Las Vueltas dictum, Tucurrique, Costa Rica, alt. 635 m., Jan. 1899, A. Tonduz n. 12962. Gilibertia stenocarpa Donn. Sm.—Folia alia indivisa oblongo- ovata vel-elliptica, alia ad medium fere trilobata, lobo terminali rotundato cuspidato, lateralibus acuminatis. Umbellae racemosae, pedicellis flores vix aequantibus. Drupa elliptica triente longior quam latior. © Arbor 1o-15-metralis. Folia membranacea subtus glandulis rubellis punc- tulata margine integra circumscriptione quam maxime variabilia, np indivisa 12-16 cm. longa 6-11 cm. lata acuminata basi cuneata utrinque penninervia, folia lobata cum praecedentibus intermixta ambitu seh suborbicularia vel transversim ovalia 11-17 cm. longa 8-20 cm. lata triplinervia, lobo terminali maxim .5 cm. longo 4-7 cm. lato dimidio superiore plerum- que semiorbiculari, sstacatibas subtriangularibus vel acuminato-ovatis 2-6. 5 cm. longis atque latis, altero insolenter obsoleto. Petioli 5-22 cm. longi Stipulae minimae rubiginoso-pubescentes. Inflorescentia terminalis. Racemi floriferi rhachis juvenilis de acge omarion: adulta 4 cm. lon 16-21 circiter 2 cm. longi parce dissite minuteque peg receptacul bracteolae rubiginoso-pubescentes, pedicelli 2. 5—3 mm. longi, flo usque ad 45 pentameri 3.5 mm. longi. Calyx obpyramidalis 1.5 mm. fee i latus minute denticulatus. Petala ovata 1.5 mm. longa scariosa staminibus paulo superata. Styli in conum 1 mm. fere altum disci dimidium aequantem toti connati. Drupae 6 mm. longae 4 mm. crassae columna stylari 2 mm. fere longa coronatae. 436 BOTANICAL GAZETTE [JUNE In praeruptis Barranca de Eminencia dictis, Depart. Amatitlan, Guatemala, alt. 1200 m., Febr. 1892, John Donnell Smith n. 2666 ex Pl. Guat. etc. ge ed. Donn. Sm. i Sante Rosa, Depart. Santa Rosa, Guatemala, alt. 1 ., Maj 1892, Heyde et Lux n. 3348 ex Pl. Guat. etc. quas ed. Donn. Sm El nays loco accuratius haud addicto, Carlos Rénson n. 66 a cicione in herb. Musei Nationalis numero proprio 576040 signatum vidi.) Gilibertiae species in America Centrali obviae ad inflorescentiam ceteris characteribus neglectis dignosci possunt, nempe: I. Umbella solitaria. G. querceti Donn. Sm. (Dendropanax querceti Donn. m. II. Umbellae racemosae. A. Pedunculi medio articulati. G. gonatopoda Donn. Sm. B. Pedunculi inarticulati. 1. Pedicelli flores vix aequantes. G. stenocarpa Donn. Sm. 2. Pedicelli flores superantes. a. Umbellae 25-40-florae. G. arborea E. March. b. Umbellae 10-20-florae. G. Rothschuhii Harms. Basanacantha (?) grandifolia Donn. Sm.—Inermis. Folia cori- acea permaxima lanceolato-vel elliptico-oblonga utrinque acuta. Stipulae numerosissime imbricatae scariosae minimae in bracteas transientes. Flores masculini pluri-aggregati subsessiles, calyce bracteis imbricatis fere velato breviter dentato. Tota stipulis praetermissis glabra. Ramuli teretes. Folia tantum suprema obvia bina 28-32 cm. longa 9-14.5 cm. lata saepius falcata utrinque nitida subtus elevato-punctulata, nervis lateralibus utrinsecus 1o—12 arcuatim anastomosantibus, petiolo canaliculato 2.5-3.5 cm. longo. Stipulae apicem interpetiolarem ramulorum obtegentes leviter cohaerentes ferrugineae late ovatae 4 mm. longae mucrone nigro cuspidatae extus punctulatae intus elongato-glandulosae et cano-villosae. Flores solum masculini visi sub- capitulati, pedicellis crassis 1.5 mm. longis. Calyx campanulatus 3 mm. longus, dentibus subulatis 1 mm. longis margine scarioso connexis. Corolla raterimorpha, tubo 5-sulcato 12 mm. longo, lobis acuminato-ovatis 7 mm. longis. Antherae inclusae subsessiles lineares 5 mm. longae apice obtusae basi retusae paulo infra medium affixae. Discus elevato-pulvinaris 1.5 mm. altus 2 mm. latus centro intrusus. Ovarii rudimentum nullum, stylo 11 mm. longo triente bifido. Bacca ignota.—Species habitu stipulisque insignis et fortasse melius genus proprium censenda. ’ In silvis prope Santo Domingo, Golfo Dulce, Comarca de Puntarenas, Costa Rica, Febr. 1896, Adolfo Tonduz n. 9878.—Ad ripas fluminis Corozal dicti, prope Santo Domingo, Golfo Dulce, Costa Rica, Apr. 1896, Adolfo Tonduz n. 9982. 1913] SMITH—PLANTS FROM CENTRAL AMERICA 437 Perymenium ruacophilum Donn. Sm.—Folia _lanceolato- ovata basi acuta trinervia serrulata supra scabridiuscula subtus glabrescentia. Corymbi remote patenterque ramosi, pedicellis trinis. Involucri bracteae 3-seriatae oblongae obtusae superne fimbrillatae. Receptaculum conicum. Rami cum ramulis remotissimis brachiatis teretiusculi sulcati glabri ee purascentes, gemmis axillaribus cano-pilosis. Folia membranacea 6. 5-9 ¢ longa 2-5 cm. lata tenuiter sciaasonestn e — etre sien calloeo-serrulata, petiolis 1. 5-2. 5 cm. longis ] Corymbi glabrescentes inferne foliis vecacian ceterum “pratieas inearibus 2-5 mm. lon- gis pubescentibus instructi, eorum bene evolutorum rhachi 2. 5 cm. longa, ramis inferioribus 2.5 cm. longis, pedicellis circiter 1. 5 cm. ae dissite et saepe su capitulo bracteolatis. Capitula oblongo-obovata ro-11 mm. longa, involucri bracteis apice purpurascentibus margine membranaceo lacerato minute mbrillatis, intimis 6 mm. longis, extimis 3 mm. longis, receptaculo 2 mm. alto atque lato, paleis flores parum amplectantibus 6-7 mm. longis acuminatis minute ciliolatis. Ligulae 6-7 circiter 9-10 mm. longae 2-3-denticulatae. Flores disci numerosi 8 mm. longi. Achenia compresso-triquetra 2 mm. longa glabra deorsum angustiora basi callosa, maturis calvis, pappi aristis numerosis distinctis ciliolatis caducissimis. vIn monte Volcén Santa Maria dicto, Depart. Quezaltenango, Guatemala, alt. 2500-3500 m., Jan. 1896, E. W. Nelson n. 3727. Arctostaphylos (§ EvarcrostApHyLos Drude.) cratericola Donn. Sm.—(A. pungens H.B. et K., var. cratericola Donn. Sm. in Bor. Gaz. 15:13. 1891.)—Folia glabra obovata vel obovato- elliptica calloso-apiculata subtus punctulata. Racemi puberuli, pedicellis flore 2-3-plo brevioribus. Filamenta nuda corolla 3-plo breviora antheris bis longiora, aristis antherae aequilongis. Fruticulus coespitosus, caulibus prostratis 3-4 dm. longis ramosis dense foliatis fuscis cortice exfoliantibus, ramulis apice trigonis puberulis ceterum glabris. Folia 14-20 mm. longa 9-10 mm. lata leviter induplicativa minute reticulata rosaceo-apiculata passim rosaceo-maculata, juniora margine pube- rula, petiolis 2-3 mm. longis puberulis. Racemi subsessiles nutantes sub- capituliformes 6-8-flori Ue bs pedicellis 2-3 mm. longis, bractea exteriore pages es ma mm, longa. Calycis segmenta suborbiculata 2 mm. longa ciliolata Had Corolla urceolata, tubo 6 mm. longo albido, dentibus sentescblouiatth 1 mm. longis reflexis rosaceis. Filamenta 2 mm. longa infra medium suborbiculari-dilatata. Discus antes Ovarium 5-loculare stylo addito corollae tubum fere aequans. Drupa ignot d rupes in cratere, Volcan de Agua, Depart. Zacatepéquez, cco. 438 BOTANICAL GAZETTE [yUNE alt. 3600 m., Apr. 1890, John Donnell Smith n. 2159 ex Pl. Guat. etc. quas ed Donn. Sm.—Volcan de Agua, Depart. Zacatepéquez, Guatemala, alt. 2700- 3100 m., Febr. 1905, W. A. Kellerman nn. 4754, 4950 Cordia gualanensis Donn. Sm.—Folia inter minima ex ovali ovata vel oblongo-ovata cuspidata integra supra scabrida subtus strigillosa. Cymae terminales folia subaequantes. Calyx esul- catus, dentibus 5 subulatis brevibus. Corolla infundibularis, tubo quam calyx bis quam lobi dimidio longiore. Stamina 4-8. Frutex ut videtur, ramis teretibus glabris. Folia 18-31 mm. longa 12-18 mm. lata, nervis lateralibus utrinque 6-7 uti venae transversales subparallelae inter se 1-2 mm. distantes et costa fuscentibus, petiolis 1-4 mm. longis. Cymae nondum satis evolutae solum visae terminales et ad apicem ramulorum brevis- simorum foliis juvenilibus instructorum pseudo-axillares fusco-velutinae 9—12- florae, pedunculo 2-3-mm. longo, rhachi 10-13 mm. longa. Calyx subsessilis campanulatus extus fulvo-sericeus intus puberulus 5-costatus minute reticu- latus, tubo 5 mm. longo, dentibus 1 mm. longis. Corollae puberulae tubus, I1-12 mm. longus, lobi 4-8 obovati 7 mm. longi. Stamina usque ad medium fere corollae tubum et subaequaliter affixa saepe inaequilonga, antheris inclusis vel breviter exsertis cordiformibus 1.5 mm. longis retroversis. Ovarium pyramidale 2 mm. longum glabrum, stylo 7 mm. longo triente bifido, ramis dimidio bifidis, stigmatibus clavatis. Drupa deficiens. ualan, Depart. Zacapa, Guatemala, alt. 122 m., Mart. 1905, W. A. Kellerman n. 5105. (Exemplum in herb. Musei Nationalis numero proprio 576295 signatum exstat.) BALTIMORE, MARYLAND VEGETATIVE REPRODUCTION IN AN EPHEDRA CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 172 WwW. i. @ faiws (WITH FIVE FIGURES) When the branches of many plants are covered with soil or even make contact with it, they may put out roots and produce new plants. This method of reproduction is common among angiosperms and to a less degree among gymnosperms, where heretofore it has been reported only for Coniferales. Many species, distributed among Abies, Picea, Pinus, Larix, Pseudotsuga, Thuja, Chamaecyparis, and Cryptomeria, produce new plants by the rooting of horizontal branches which then either erect the tip of the rooting branch or send out erect lateral shoots. The unfortunate term “layering” has been applied to this method of vegetative reproduction. The latest account for a gymnosperm is that of Cooper’, who describes “layering” in Abies balsamea and cites the scanty literature of the subject. Until now no special method of vegetative reproduction has been reported for Gnetales, perhaps because the relative inaccessi- bility of the group has prevented careful field studies. In September ro11 occasional clumps of an Ephedra were found on the very steep rocky sides of the cafion of Rifle Creek, near the southern boundary of the White River forest reserve in western Colorado. This Ephedra is probably conspecific with E. nevadensis, although differing from the latter in some minor characters. Rifle Creek, where it falls over the edge of the White River pla- teau, for some miles has carved out of very hard limestone a box cafion with walls in some places rising perpendicularly to a height of more than 150 meters (fig. 1), or even leaning outward over the cafion floor. Emerging from the box cafion the stream flows for OOPER, Wrt.1aM S., Reproduction by layering among conifers. Bot. Gaz. * Coo 52: 369-379. fig. I. 1911 439] - [Botanical Gazette, vol. 55 440 BOTANICAL GAZETTE [JUNE a short distance through soft limestone with regular slopes steeply V-shaped, then through sandstone conglomerate, which being very friable weathers rapidly. The faces of the sandstone slopes show a series of low cliffs (fig. 2) alternating with nearly bare talus. The walls of the cafion are exceedingly unstable. Ephedra is sparsely distributed along the cafion walls for nearly four miles, occurring only on the most exposed and most unstable slopes in clumps of from four or five plants to sometimes twenty 1.—Limestone cliff at entrance to the box cafion of Rifle Creek, near the Fic upper limit of Ephedra, which is found in small quantities at the top and in the talus slope at the base. or infrequently more. Isolated plants are rare and an examination of one of these showed that it had been torn from a clump on a cliff above by a small landslide. The vertical range is as sharply limited as is the horizontal, no plants being found at an altitude below 2000 nor above 2200 meters. The clusters are most abundant on the sandstone slopes, the greatest display and most vigorous plants being near the lower limiting altitude (fig. 2); thence running up the ridges between the small side cafions and becoming 1913] LAND—EPHEDRA 441 fewer and fewer until they completely disappear at 2200 meters. Rarely plants are found growing in the scanty bowlder-strewn soil on ledges along the face of the limestone walls of the box cafion. In one instance a small clump was seen on the extreme edge of the great cliff (fig. 1) which towers above the cafion floor. In the coarse limestone talus at its base were a few plants, much battered by falling stones. This cliff, rising almost to the vertical range of Ephedra is capped by a steep ridge of the coarse friable sand- Fic. 2.—Ephedra on sandstone talus near lower limiting altitude; dead Pinus edulis in foreground; a typical situation. stone of the lower cafion. Here also were a few small clumps of depauperate plants. Ephedra was not found on the relatively moist, well-wooded north slopes nor in the cafons of adjacent watercourses, but the rough nature of the country made extended search somewhat difficult. Some plants reach a height of 2.5 meters, and below the first branching, which is usually at the surface of the soil, may attain a diameter of 1ocm. The largest trunk found (fig. 3) had a diameter of 5 cm. just above the first fork. The greatest number of seasonal 442 BOTANICAL GAZETTE [JUNE rings found was 40, showing that the plant is comparatively short- lived. Associated with Ephedra are occasional plants of Artemisia tridentata, the older ones much battered by snowslides and rolling stones, and quantities of Cercocarpus parvifolius, the mountain mahogany. Rarely indeed in the sandstone talus a plant of Equisetum is found. On more stable slopes Pinus edulis and species of Juniperus are fairly abundant. The general instability of the G. 3.—An old Ephedra on a comparatively stable slope; the oldest plant found in ees region, having 40 growth rings. region is well shown in fig. 2, where a pine has perished because of the rapid wearing away of the sandstone cliff. A careful and persistent search throughout the range of Ephedra was made for seedlings, but since none could be found, it seemed evident that such a short-lived plant, in order to maintain itself under the severe conditions imposed by its habitat, must have some method of vegetative reproduction. The almost universal occurrence of clumps led to a careful examination of the under- ground condition. In nearly every instance it was found that the 1913] LAND—EPHEDRA 443 individuals ofa group are either actually connected by means of underground stems or that traces of a former connection could be made out. Sections show that these underground connections are stems and not roots. Large boulders and masses of friable rocks are continually being detached from the cafion walls, and these, together with deep accumulations of snow, are sufficient to overthrow even the largest plants of Ephedra, as is shown in fig. 4. At the right, in this figure, aut “Ee 3 aif Fic. 4.—A clump of Ephedra showing large plants being overthrown by boulders two boulders are bending down one of the largest plants of the clump. The branches of this plant will finally be forced into con- tact with the soil, most likely be covered with talus, take root, and give rise to a new cluster of plants. An almost completely decayed trunk was found under the boulder shown at the extreme left of the figure. This trunk had given rise to a small clump not shown. Young plants are so slender that they are easily overthrown and buried by small landslides. On a loose and rapidly moving slope composed of small stones and coarse sand, underground connec- tions were traced for 5 meters. The oldest plant showing five 444 BOTANICAL GAZETTE [JUNE seasonal rings was above and the younger ones farther down the slope, stretched out in an almost straight line by the flowing talus. After a stem has been buried it is sometimes difficult to detect the growth of succeeding seasons. Underground stems rising from stems which have been buried for some years were found creeping among the loose stones and coarse sand of the sandstone slopes. These shoots are, in effect, rhizomes which later produce aerial shoots either by branching or by erecting 5.—Underground connections of a small clump of Ephedra found in the talus deed ‘. the extreme right of fig. 2; a, young rhizome; , older rhizome which has sent up an aerial shoot; c, rhizomes whitch have erected their stem tips. the main stem tip, or by both methods. The rhizome habit is shown in fig. 5. The branched underground shoot a, springing from the buried stem which has also given rise to the damaged cluster of aerial branches, has grown in one season (1911). At d is an older stem which has produced an aerial branch. At ¢ is a stem which has branched, and the branches, after a time, have become aerial by erecting their tips. The rhizomatous branches were not found where the soil is compact, being only in loose sand and small stones. It seems worthy of note that the soil above 2200 meters, the upper 1913] LAND—EPHEDRA 445 limiting altitude of Ephedra, is compact. Since the tendency of soil movement is to force the plant constantly toward lower alkti- tudes, if it were not for underground lateral branching, Ephedra would first be driven from the higher slopes and ultimately from the region. If Ephedra does produce seeds in this region they are promptly destroyed by small animals. Not many seedlings of pine and spruce are found, although great quantities of seeds mature. Spruce seeds are eaten by squirrels as soon as they ripen and long before they fall. Great numbers of pifion jays visit the region in autumn and feed on the nuts of Pinus edulis. However, pifions and spruces are so abundant that enough seeds to keep up the forest are over- looked. It is regretted that observations cannot soon be made to determine if Ephedra really does set seed in this region. Most of the branches of this Ephedra fall at the close of summer, a regular absciss layer being developed at each node. In September the ground under the plants is green with the fallen branches. Ephedra nevadensis was found in western Colorado only on the most bleak and unstable slopes and does not seem to be widely dis- tributed. No seedlings were found. The plant propagates itself vegetatively by shoots, which, after having been overthrown and buried by talus, take root, erect their tips, and send out erect lateral branches; and also by means of underground rhizomes which are given off from older buried shoots. These rhizomes either send up branches or erect their tips or they may do both. They may also send out other rhizomes. Assuming the absence of seeds, Ephedra owes its preservation in this region to the rhizome-forming habit. If it were not for this habit and if other factors which are not apparent at present did not intervene, soil movement would ultimately force the plant below the lower limiting stage and cause it to disappear entirely from the region. UNIVERSITY OF CHICAGO PROTOPLASMIC CONTRACTIONS RESEMBLING PLAS- MOLYSIS WHICH ARE CAUSED BY PURE DISTILLED WATER W, J..V.-OSTERHOUT (WITH SIX FIGURES) True plasmolysis is produced only by solutions which are hypertonic, but appearances almost or. quite indistinguishable from it may be brought about by hypotonic solutions." Some light is thrown on the nature of this result by a study of certain cases in which it is caused by pure distilled water.’ Material for such study is afforded by marine plants. The root tips of the eel-grass (Zostera marina) are well adapted to this purpose. The roots were carefully removed from the sand in which they were growing and immediately placed in sea water. Some of the younger roots (which had not yet become brown at the end) were selected. About an inch of the root tip was removed and placed on a hollow-ground slide in such a way that the young root hairs did not come into contact with the glass. The root tip was covered with sea water and examined without a cover glass (by means of an 8 mm. objective and an ocular magnifying ten times). Root tips which were shown by such examination to be normal in appearance were fastened by means of vaseline to cover glasses which were then attached to irrigation chambers of the form shown in fig. 1. Care was taken to prevent the young root hairs from touching the glass or the vaseline. The arrangement of the apparatus may be understood from figs. 1 and 2. The irrigation chamber consists of an ordinary * Cf. Bot. Gaz. 46:53. sate * Water t ice distilled from glass i ll led as] ug samedi ~~ o - ath. Pg sy Pe ., : i ey as any part of the apparatus is new. The water eed 1 in the ese experiments was pre- pared with due regard to these facts. In place of stoppers, plugs of absorbent cotton were used; contamination by spattering was prevented by baffling plates of glass and glass wool. The water so obtained was not toxic to such test objects as sensitive species of Spirogyra and the root hairs of Gypsophila. Botanical Gazette, vol. 55] [446 1913] OSTERHOUT—PROTOPLASMIC CONTRACTIONS 447 glass slide with a circular opening (15 mm. in diameter) into which is fitted a glass cylinder (¢c) 12 mm. high upon which is cemented a glass disc (d) ; surrounding this is another cylinder, the width of the space between the two being about 1 mm.; a part of this space is filled with paraffin (e). The outer cylinder is pierced on ' both sides by small glass tubes (0, 6). The outer cylinder projects above the inner so that when the cover glass (f) is in place the width of the space between (d) and (/ ) Fic. 1.—Sectional views of irrigation cham- is a little less than 1 mm. ber: a, slide; }, inlet and outlet tubes; c, glass It is necessary to have cylinder; d, glass plate; f, cover glass (upper line) : : sr material (lower line). this space narrow, since otherwise when introducing a solution of greater specific gravity than the one with which the chamber is filled, the new solution may flow over the bottom of the space without coming into contact with the plants, which are fastened to the under side of the cover glass. The paraffin (e) extends downward to the slide; the liquid is in consequence obliged to pass upward through the space between (d) and (/) before it can flow out at the opposite side, and it must Fic. 2.—Material in irrigation cham-~ therefore bathe the plants ber: ¢, glass cylinder; f, cover glass; & which are attached to the - material; 4, bits of cover glass; 7, vaseline. —Sectional view. cover glass (f). The attachment is made in the manner shown in fig. 2. The plant is first fastened to the cover glass (f) by vaseline (i, indicated by the dotted area) and a drop ba 448 BOTANICAL GAZETTE [JUNE of sea water is placed on it; bits of cover glass (hk, #) are then thickly covered with vaseline, and pressed down upon it to hold it in place. The outer cylinder is smeared with vaseline and sea water is then poured into a funnel which is connected by a rubber tube with the inlet tube (b); as soon as all the air has been expelled from this tube and the chamber is so full of sea water that the surface of the liquid is decidedly convex, the cover glass (with the attached root tip) is inverted and pressed down upon the outer cylinder in the manner shown in the figure. Care should be taken during the subsequent irrigation not to admit air to the inlet tube. Fics. 3-5.—Optical section of young root hate ‘cll : Zostera marina caaipeagg matic); fig. 4, the cell s' i after ema with dudikd * water lie: grammatic); fig. 5, the cell shown in fig. 4 after more prolonged treatment with distilled water (diagrammatic). After being placed in the chamber, the root tips were irrigated for a time with sea water while camera lucida sketches were made of root hairs in various stages of development. Each of the cells which had been sketched was than kept under observation during the subsequent irrigation with distilled water. Root tips which were irrigated with sea water throughout the experiment served as controls. The application of distilled water causes a contraction of the protoplasm which often closely resembles the true plasmolysis produced by hypertonic sea water (which has been concentrated | by evaporation) or by hypertonic sugar solutions. Figs. 4 and 5 show the appearance of such cells. The mode and the degree 1913] OSTERHOUT—PROTOPLASMIC CONTRACTIONS 449 of contraction vary somewhat, but in general the variations in true plasmolysis are of the same sort as in what may be conveniently called the false plasmolysis. We may use the term “false plasmolysis”’ to designate not only the contraction produced by distilled water but also that which is caused by hypotonic solutions. The contraction may a place rather slowly, in many cases requiring half an hour or more to reach the stage shown in fig. 4. True plasmolysis may take place much more rapidly. But this distinction does not hold generally, for in many cases contractions which closely simulate true plasmolysis may take place with great rapidity. To give a single example of this, the behavior of the colorless terminal cells and of hairs of Polysiphonia violacea’ may be described. On being irrigated with distilled water these cells contract very rapidly, so that at the end of two minutes they reach the stage shown at the right in fig. 6, in which they are practically indistinguishable from cells’ plasmolyzed by hypertonic sea water or hypertonic sugar solu- See tions. The older cells reach the same stage Fic.6.—Surface more slowly and betray by the alteration of their view of the endofa chromatophores that they are undergoing false plasmolysis. It should be noted that by apply- in natural condition; ing hypertonic solutions of many salts, both attheright after true and false plasmolysis may be produced treatment for two simultaneously. These contractions are (as a tilled water (dia- Tule) irreversible, at least as soon as they have grammatic). passed a certain stage. | The effects which have been described as due to distilled water were also produced by water taken directly from ponds, rivers, and springs; they are not due, therefore, to toxic substances resulting from the process of distillation; this point is emphasized because attention has previously been drawn to the 3 Kindly identified by Dr. W. G. FarLow. 450 BOTANICAL GAZETTE [JUNE fact that water distilled in a metal still produces such results in Spirogyra, while pure distilled water does not. The cause of these effects lies in an increase in the permeability of the plasma membrane (and likewise of internal cell membranes), as the result of which some or all of the substances which main- tain the osmotic pressure of the cell diffuse out; the protoplasm then shrinks as the result of loss of water from the vacuoles, which in consequence become smaller, as is shown in figs. 3-5. This is often followed by an apparent “coagulation” of the protoplasm, which is sometimes evidenced by the assumption of an irregular outline. Most of the characteristic features of cytolysis as described for animal cells are lacking. In some cases, however (particularly in cells which are not surrounded by a cell wall), they occur. These effects might naturally be ascribed to the absorption of water by the protoplasm, but they cannot be due to this cause, for observation shows that the cells do not increase in size as they would if water were absorbed. In some cases a few of the cells burst when transferred to distilled water, but the majority do not _ burst or even swell noticeably. This is probably due in some cases to the fact that swelling is prevented by the cell wall, for some cells which lack the cell wall (for example, spores of Polysiphonia) may swell in distilled water. Moreover, it was found that isotonic solutions of cane sugar produce the same effects as distilled water although not as rapidly. The increased permeability must be due, therefore, to the loss of certain substances upon which the maintenance of the normal permeability depends. The most important of these are undoubt- edly the inorganic salts. If the concentration of salts be lowered beyond a certain point, the permeability of the membrane increases very rapidly. This is shown by experiments in which the increase of permeability is directly measured by electrical means. In sea water plus an equal amount of distilled water the cells do not shrink, but with the addition of three volumes of distilled water they may begin to shrink in seven hours or less, and with increasing amount of distilled water shrinkage takes place more and more rapidly. These remarks apply only to balanced solutions such as sea water. 1913] OSTERHOUT—PROTOPLASMIC CONTRACTIONS 451 The effect of unbalanced solutions on permeability has been dis- cussed elsewhere.* The facts described above have an important bearing on certain theories recently advocated by some biologists and colloid chemists. According to these authors, the effects which are usually attributed to osmotic pressure are in reality due to imbibition or to the giving up of water by the protoplasm, without the intervention of a semi- permeable membrane. It would not be possible on this theory to account for the shrinkage of the protoplasm of a cell to half its volume when transferred from sea water to distilled water, espe- cially when the process is irreversible. But the explanation given above—the increase of permeability of a semipermeable membrane —not only agrees with the facts described here, but also with those derived from a variety of other material, and by the use of entirely different methods. LABORATORY OF PLANT PHYSIOLOGY VARD UNIVERSITY 4 Science, N.S. 35:112. 1912; 362350. 1912. REPRODUCTION BY LAYERING IN THE BLACK SPRUCE CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 173 GEORGE D. FULLER (WITH SIX FIGURES) During the summer of 1912, while making some ecological studies along the Saguenay River, Quebec, attention was directed ™ Fic. 1.—The black spruce growing on granite with a basal whorl of prostrate branches; ‘Celina’ County, Quebec. to the process of forest development upon granitic areas with very little soil, where the rocky surface was exposed to the full sweep of the wind. The most careful studies were made on a series of Botanical Gazette, vol. 55] [452 1913] FULLER—LAYERING IN BLACK SPRUCE 453 granite hills with typical roches moutonnées contours and with eleva- tions varying from 100 to 200 meters, in Chicoutimi County, border- ing an arm of the river known as Ha! Ha! Bay. In these exposed situations there occurred a characteristic pioneer forest association consisting, as far as its tree species were concerned, of black spruce (Picea mariana Mill. BSP.), Jack pine (Pinus Banksiana Lamb.), the white birch (Betula alba papyrifera (March.) Spach.), and the aspen (Populus tremuloides Michx.), together with occasional trees Fic. 2.—The prostrate branches of the black spruce rooting in the mat of mosses and lichens and producing upright shoots; one such shoot has been provided with a white background. of a few other species. Because of the slow weathering of these areas, the pioneer stages of forestation were much prolonged, but appeared to be promoted by the development of a peculiar growth habit and a resulting vegetative reproduction by layering. This habit was most highly developed and occurred most frequently in the black spruce. Grown in swamps or thickets the black spruce is characterized by a narrow irregular cone of branches. This cone was found to be 454 BOTANICAL GAZETTE [JUNE even more slender in the sparse stand upon the granite surfaces, but in these open situations there were in addition to the short branches on the upper part of the trunk longer ones near the surface of the rock (figs. 1 and 2), forming a compact mat, none of the twigs more than half a meter high. At least one-half of the total foliage of the trees was usually upon these prostrate branches, and it would seem from the apparent vigor of the leaves that an even larger proportion of the work of food synthesis was to Fic. 3.—A dead stump of black spruce with a circle of living offspring from its layered branches. be referred to this lower stratum. The rooting of the trees in these rocky habitats was, as a rule, very shallow, and hence the massing of their branches reduced the exposure to winds and the consequent danger of uprooting. The habit was necessarily con- fined to open stands. The mat of lichens and mosses which antedated the tree con- tinued to thrive under and among the prostrate branches and the resulting soil soon buried portions of the lower members of the mass. On Pinus Banksiana this was apparently without results other than 1913] FULLER—LAYERING IN BLACK SPRUCE 455 Fic. 4.—A rooted branch of black spruce the result of layering; the upright shoot is ie one with the white background in fig. 2 Fic. 5.—A layered branch of black spruce 456 BOTANICAL GAZETTE [JUNE somewhat more securely anchoring the trees, but on the spruces it often stimulated the production of roots from the buried branches and caused a circle of young trees to surround the parent (fig. 2). Such reproduction in conifers was recently discussed by COoPER,* who also gave very complete citations of the scanty literature of the subject. The layering habit in Picea mariana has been mentioned by Loupon,? for specimens growing under partial cultivation on the British Isles, but its importance in increasing the stand upon Fic. 6.—A group of young black spruce descended by layering from a single parent tree; the remains of the dead parent are concealed by the young trees; Chicoutimi County, Queb rocky areas seems to have escaped notice. The fact that the rate of growth has been found to be very slow in such localities’ makes such a method of rapid multiplication and replacement an even greater advantage to the species possessing it. Should trees * Cooper, W. S., Reproduction by layering among conifers. Bort. Gaz. 52:369- 379. IQII. 2Loupon, J. C., Arboretum et Fruticetum Britannicum. London. 1844. 3 Cooper, W. S., The climax forest of Isle Royale, Lake Superior, and its develop- ment. II. Bor. GAz. 55:115-140. 191 1913] FULLER—LAYERING IN BLACK SPRUCE 457 of the black spruce growing on granite be cut down, their early replacement is much more definitely assured (fig. 3). By this layering circular areas with a radius of 2-4 meters soon become covered with vigorous young upright shoots, like the one provided with a white background in fig. 2, which is 2.4 meters from the main trunk. This shoot was removed from the soil and proved to be one of two upon a prostrate branch rooted at several points throughout its length (fig. 4). The orthotropic develop- ment of the shoot is well marked, while several other twigs showed it in a less marked degree. The development of such shoots seems to be closely connected with the production of adventitious roots, although not always dependent upon it. Occasionally an abun- dance of adventitious roots was unaccompanied by any definitely orthotropic shoots (fig. 5). This was frequently noticed in the layering of Abies balsamea as it occurs in its shrubby habit in the deeper forests. The layering was seldom found on Picea canadensis, because this species rarely occurs in exposed rocky situations as a member of the pioneer forest association. By far the greatest importance of the habit, in the Saguenay region, is its abundance in the black spruce. Often large clumps of small trees could be referred to the parentage of.a few individuals, although with increase in size the connections became increasingly difficult to trace. Frequently clusters of 6-20 closely clustered young trees (fig. 6) marked the spot where a tree of a former generation stood, showing much more rapid replacement than could have been effected by seed. UNIVERSITY OF CHICAGO BRIEFER ARTICLES THOMAS HOWELL (WITH PORTRAIT) Mr. Toomas HowELt, the pioneer botanist of Oregon, died on Decem- ber 3, 1912, in Portland, at the age of 70 years. He was born near Pisgah, Missouri, October 9, 1842, whence he moved to Oregon in 1850, before railroads had entered the state. Although he received a meager school education, he was a well learned man and an enthusiastic botanist. He did not marry until his 54th year. His wife and a son of seven sur- vive him. Just before his death he completed the second edition of his Flora of Northwestern America, replacing the BENTHAM and HooKER system with that of ENGLER and Prantt. This publication embodies the life work of Mr. HowE Lt, who spent more than 30 years tramping and traveling over the states of Washington and Oregon. Considering the vast area of these states, and the vicissitudes of pioneer life in that far isolated country, the task of accumulating the data for such a complete flora of the region is realized. Naming the localities worked in these states would require much space; suffice it to say, that the only places he did not visit were portions of central northern Washington and of the central part of Oregon. It is not known to the writer how much material he collected; the Field Museum alone has 2263 specimens. His flora lists and describes about 3290 species. It was the good fortune of Mr. HowE Lt to discover and describe the last of the Pacific coast conifers, Picea Breweriana, the weeping spruce, a very local tree near the Oregon- California line, which he first found at Waldo, in the Siskiyou Mountains, at an elevation of 6000 feet. Mr. HowELL was materially unfortunate in having lived in a region where his knowledge of systematic botany yielded him no financial remuneration, save from the limited sale of his book. His love of study and enjoyment of the vastness of the Pacific Northwest he considered ample reward. The sad part of his later life was his limited finances. For the last several years he was compelled to live in a poor foreign section of Portland, eking out a frugal existence in a small grocery- confectionery store, which also served as his residence. When visited last by the writer, he was making coarse teamsters mittens on a sewing Botanical Gazette, vol. 55] [458 BRIEFER ARTICLES 450 1913] 460 BOTANICAL GAZETTE [JUNE machine for seven cents a pair. Under such conditions was his book revised. r. HOWELL, however, was very cheerful at all times and betrayed no impatience with depressing external conditions. According to his own statement, the picture here produced is the only one ever taken of him. It represents him seated at his typewriter with the first copy of his revised flora. Behind him are seen stacks of com- pleted mittens. It was made by the writer during a visit, October 14, 1910.—Huron H. Situ, Field Museum of Natural History, Chicago. THE SEEDLING OF PHYLLOCARPUS (WITH ONE FIGURE) When recently collecting insects at Gualan, Guatemala, Mrs. COCKERELL was so fortunate as to senover a new species of Phyllocar pus, a genus previously known from a single species found in Brazil. It is a large tree, with magnificent red flowers, much visited by insects. The circumstances ee -attending the discovery 1.—Seedling of Phyllocarpus, n. sp.. have been related at some from Gu salen, Guatemala, by W. P. Cocxerett; length in the Canadian apical leaflet not expanded. Entomologist (September IgI2, pp. 278, 279). Seeds were later obtained by Mr. E. Morris, and we were successful in getting some of them to germinate. I described the seedling in an early stage, before the fleshy cotyledons had appeared, and was away from home during the development of the later stages. From the accompanying figures it will be seen that the seedling is essentially like that of Caesal- pinia. At the stage represented by the figures, the following characters are apparent: Epicotylar stalk strongly pubescent, with spreading fine hairs as long as half its diameter, and more abundant short curled ones; petioles the same, only more hairy; first leaves 7-foliolate; leaflets light pea green, rather broad lanceolate, quite entire, nearly sessile, but inequilateral at base; perfectly glabrous except the margins, which are densely white- hairy, and the midribs beneath, which are hairy like the petioles.—T. D. A. CocKERELL, University of Colorado, Boulder. CURRENT LITERATURE MINOR NOTICES A new color guide.—A new color guide by Dr. Ropert RmwGway,' the well known ornithologist, is practically an entirely revised and much enlarged edition of his earlier nomenclature of colors (1886) with 17 plates and 186 colors as against 53 plates and 1115 colors in the present work. The color work was done by A. Hoen & Co., Baltimore, and is much more uniform in different copies than in the earlier edition, which was hand-stenciled from several mixings of the same color; while in the present work each color for the whole edition of 5000 copies was prepared from one lot of color and uni- formly coated at one time. The work is designed to be equally useful to botanists, florists, artists, dyers, merchants, and chemists who require a standard color scheme. The colors have evidently been standardized to a degree of accuracy not hitherto attained in any color chart. The colors are one-half by one inch, arranged on a heavy gray paper in three vertical columns of 7 colors each. All the colors are named as well as symbolized, but if a given color comes between “hermosa pink” (xf) and “‘eosine pink” (1d), it could be designated 1e. In this manner about 2385 additional colors or a total of 3500 can be designated. Undoubtedly exception will be taken to some of the names, but in this the personal equation plays such a large part that decisions must be rather arbi- trarily rendered. The primary colors have been standardized by Dr. P. G. Nurtinc of the U.S. Bureau of Standards. A table of percentages of color, together with an explanation of the amount of white, black, or neutral gray used as above, will give an approximately ready clue to the reproduction of any color in the guide, the only epee factor being the possible lack of standardized primary colors to begin wi Defini- tions of the principal color terms, such as color, shade, tint, Pg ‘ise, ete., which are used almost interchangeably by aoa people, will repay c study by those not familiar with their exact u A slight error on p. 12, due to a Siena should be corrected. Mr. F. A. WALPOLE had no connection with the color project of the American gg eager Society, the preparation of which was delegated to the late Dr. L. M. Unb oop, Dr. W. A. Murritt, and the writer. Mr. WALPOLE died before "the committee was appointed, and the project was abandoned after two years’ work by the committee in favor of Dr. Ripcway’s work which had not previously come to their notice.—P. L. RICKER. * Rpeway, Rosert, Color standards and color nomenclature. Pp. 44. pls. 53. Published by the author (3447 Oakwood Terrace N.W., Washington, D. wee 1912. $8.00 461 462 BOTANICAL GAZETTE [JUNE Homologizing plants and insects.—In attempting to homologize the various parts of plants and insects, JANET? has succeeded in proposing several additions to our already overloaded vocabulary. The sporangium of Mar- chantia contains “‘isogynospores” and ‘‘isoandrospores,” while that of Selagi- nella contains ‘‘macrogynospores” and “macroandrospores.” The vocabulary consists mostly of words like these, which are easily understood but unnecessary and not at all likely to become a permanent part of our burden. The plant atest te consists of a gametophyte, beginning with the spore and end- ing with the “‘gynogametes” and “androgametes,” and a sporophyte, beginning with the zygote and probably including the rest of the life history, although the table gives the sporangium (called the “‘gynosporangium’’ and “‘andro- sporangium”’ in Selaginella, and = Te and pollen sac in spermatophytes) as the final member of this genera The insect is an ‘‘orthozoite,”’ eeciine of a ‘‘gametozoite” and a “sporo- zoite”’ generation. The gametozoite coayaiata begins with a generative cell (cellule Eeoitale) which produce “‘gonads,’”’ gametangia, and finally “‘gyno- gametes” and “androgametes.”’ The sporozoite generation begins with the fertilized or parthenogenetic egg, and includes the rest of the life history. Several years ago the reviewer tried to show3 that, in animals as in plants, generations are characterized by the haploid and diploid number of chromo- somes. JANET’s paper is based upon current knowledge rather than upon any new evidence, ‘Loetugaiies we agree with him, or rather he agrees with us, that there is an alte g in animals.—CHARLES J. CHAMBERLAIN. Flora of New Guinea.—Another volume of the botanical results of the Dutch scientific expedition to New Guinea (1907 and 1909) under the auspices of Dr. H. A. Lorentz has now appeared.4 The first part of the botanical report was reviewed in this journal.s The collaborators are as follows: S. H. Koorpers, L, RADLKOFER, A. PULLE, J. VALCKENIER SURINGAR, E. ROSEN- sTocK, MAX FLEISCHER, TH. VALETON, J. J. SMirH, A. ENGLER and K. Krause, C. LAUTERBACH, J. PERKINS, and L. Diets, 72 families and 292 genera being represented, including 599 species, 153 of which are new. Three new genera are published as follows: Capitularia (Cyperaceae), Gjellerupia (Opiliaceae), and Nouhuysia (Guttiferae). Most of the families are introduced merely to 2 JANET, CHARLES, Le ndvogeyie et le — os du ici os soma et le germen de linsecte. 8vo. pp. 65. Limoges: Ducourtieux et Gott. 3 CHAMBERLAIN, CHARLES J., pesca of generations in i. from a botanical standpoint. Bor. Gaz. 392137144. 1905. 4 Nova Guinea. Récuitate dal’ 2 atete Re Aas Ala Nouvelle- Guinée, en 1907 et 1909, sous les auspices du Dr. H. A. LORENTZ. Vol. VIII. Botani- que. Livraison IV. 4to. pp. 613-898. pls. 113-159. Leide: E. J. Brill. 1912. Fr..27. 50. 5 Bot. GAz. 492464. IgI0. 1913] CURRENT LITERATURE 463 include some additional species, but the Cyperaceae (19 genera and 97 species, 6 of which are new), Rubiaceae (16 genera and 36 species, 11 of which are new), and Filices (39 genera and 86 species, 18 of which are new) are presented with a measure of completeness. Aside from these families, the largest additions of new species are to Ericaceae (14), Euphorbiaceae (12), and Musci (10).— j-M.C Paleobotanical literature.—The third volume of JoncMANn’s Die. palaeo- botanische Literatur has appeared,® including the bibliography of 1910 and 1g11. The great usefulness of this publication needs no explanation, and now that paleobotany has come to be an essential part of the morphology of vascular plants, it will serve a much larger group of botanists than the title once would have indicated. The list of authors (40 pp.) includes 374 names, representing 762 titles. The list of literature is admirably re emcie so that almost any clue can be followed to the literature of a subject.—J. M NOTES FOR STUDENTS The mucors.—Prominent among recent publications on the Mucoraceae are two papers by HAGem? which deal with the distribution, taxonomy, and physiology of the soil-inhabiting mucors occurring in the vicinity of Christiania, Norway. Asystematic search has revealed the presence in the soil of an unsus- pected wealth and variety of these organisms, strangely in contrast with the rarity of their spores in the atmosphere. = the first paper, which deals with Of taxonomy and distribution, 20 species are described. these, 16, includ- ing 7 new species, were isolated from eae anus the cong: ost of th i many times and some da ese Among the most Sone encountered species, Mucor racemosus, M. oe and M. nodosus are abundant in cultivated lands; M. Romannianus is most frequent in coniferous forests (50,000 spores per gram of soil), but M. strictus, M. flavus, and M., sylvaticus are also common. , Some forms like M. racemosus, - M. hiemalis, Absidia Orchidis, and Zygorynchus Moelleri are widely distributed both in cultivation and in forest soils. As showing the rarity of the spores of mucors in the air, only 8 species were isolated by means of Petri dishes con- taining culture media, and exposed for periods of 1-2 hours both in town and country. The second paper deals chiefly with problems of nutrition. A large num- ber of compounds were tested with respect to their availability as sources of 6 Joncmans, W. J., Die palaeobotanische Literatur. Bibliographische Ubersicht iiber die Avbelien aus ae Gaius der Palaeobotanik. Dritter Band. Die Erschei- nungen der Jahre 1910 und rg11 und Nachtrige fiir 1909. pp. 569. Jena: Gustav Fischer. 1913. 26. 7 HaGEM, _ Untersuchungen iiber ue scree * Vidensk. Selsk. Skrift. no. 7. pp. 50. figs. 22. 1907; ibid. IT. no. 4. pp. 152. 19 464 BOTANICAL GAZETTE [JUNE nitrogen and of carbon for the mucors. The mass of detail is too great and too diverse to permit of recapitulation; the main features of the results, how- ever, may be briefly summarized. The 23 mucors studied fall into two clearly separated groups with respect to their ability to assimilate nitrogen from nitrates and nitrites. In relation to these compounds it is interesting to note that all forms which were capable of assimilating nitrates were also capable of assimilating nitrites. As with other plants, the nitrates are reduced to nitrites and these to ammonia in the process of assimilation. All forms grew well when nitrogen was supplied in the form of ammonium salts. On urea, 18 species thrived, but Mucor Romannianus failed. In cultures with urea, ammonium carbonate is formed. Acetamide is not utilized. Uric acid is only slightly soluble, but gives good growth. The amino-acids have little nutrient value when they are the sole source of both carbon and nitrogen. When carbon is supplied in the form of glucose, the amino-acids, especially leucine and tyrosine, are utilized as a source of nitrogen by many of the soil mucors. In all cases ammonia accumulates in the culture medium. Of the non-nitroge- nous carbon compounds, mannite and glycerin are not used when ammonium sulphate is the only source of nitrogen; with potassium nitrate, however, these polyatomic alcohols are assimilated by 3 or 4 species. With the exception of reducing sugar in the culture fluid. The species which thrive on saccharose are unable to utilize that sugar when amino-acids serve as the only source of nitrogen. In explanation the author suggests that the action of the inver- tase of the fungi is inhibited by the presence of ammonia split off from the amino-acids. Starch in general seems not to be utilized, a fact which is all the more interesting since the conversion of starch into glucose by some species of izopus is the basis of a commercial process. Few species grow on inulin and pectin, but some on xylan and cellulose. Of the glucosides, helicin and salicin were tried. Helicin proved valueless, while a number of mucors were capable of utilizing salicin, but only to a limited extent because of the toxic properties of the decomposition products formed. These results on the whole seem to indicate that most of the common substances which reach the soil from the plant are only poorly suited for the nutrition of a group constituting, according to these investigations with the exception of the bacteria, one of the most abundantly represented classes of soil-organisms. It would be an interesting problem to determine to what extent the nutrition of soil mucors is dependent upon decomposition of plant products brought about by bacteria and other soil organisms. In a third paper,’ which forms the conclusion of HAGEm’s investigations of Norwegian mucors, the author gives critical notes on their nutrition. Mucor 8Hacem, O., Neue ooaeasew iiber norwegische Mucorineen. Ann. Myc. nialeien: figs. II. 1910 1913] CURRENT LITERATURE 465 saturninus, M. christianiensis, M. dispersus, and-M. corticolus are described as new in this paper. M. norwegicus Hagem, which was described as new in the first paper, is here regarded as a synonym of M. (Rhizopus) nodosus (Namys- lowski) Hagem. AMYSLOWSKI? describes a new species of Zygorynchus isolated from the . This species, like the other species of the genus (Z. Moellerii and Z. heterogamus), is monoecious. In another paper,“ NAMYSLOWSKI has reported a long series of experi- ments in which, after the fashion of Kiess, he attempts to determine the influence of various food substances in different sgaspatie on the produc- tion of zygospores and sporangia by the mucors. e data do not allow of either general or precise conclusions, but show that a kind and concentration A number of short papers by different authors treat of the formation of zygospores and of nuclear phenomena in the mucors. LENDNER™ has examined the method of origin of the zygospore in a number of mucors representing both monoecious and dioecious species. His observations go to show that the gametangia originate at points where two branches of the mycelium accident- ally come into contact, and not, as is usually stated, on branches which grow toward each other as the result of some sort of a stimulus. Moreau,” who has studied nuclear phenomena in the hyphae and zygospores of several mucors, reports that the divisions in the hyphae and gametangia are normally mitotic and simultaneous. In the columella of Rhizopus amitotic divisions, which 9 NamMysLowskI, B., Zygorynchus Vuilleminii, une nouvelle mucorinée isolée du sol et cultivée. Ann. Myc. 8:153-155. figs. 9. 1910. t0 NAMYSLOwsKI, B., Studien iiber Mucorineen. Bull. Intern. Acad. Sci. Cracovie. Ser. B. seis Jigs. 2. LENDNER, A., Observationes sur les zygospores des Mucorinées. Bull. Soc. Bot. searing IL 2256-59. figs. 4. 1910. 12 MorEAU, F., Premiére note sur les Mucorinées, le noyau au repos.—Le noyau en division: mitose et amitose. Bull. Soc. Mycol. France 2'7:204-210. figs. 12. 1911. , Deuxiéme note sur les Mucorinées.—Fusions de noyaux et dégénére- scence auciidatpe dans la zygospore.—Fusions de noyaux sans signification sexuelle. Tid. 334-341. figs. 4. , Les phénoménes internes de la reproduction sexuelle chez — Abucusiobos hétérogames. Bull. Soc. Bot. France §8:618-623. jigs. 4. 1911 466 BOTANICAL GAZETTE [yUNE apparently indicated degeneration, were observed. In the zygospores he finds that multiple fusion with degeneration of the supernumerary nuclei takes place. The fusion is preceded by a division. Zygorynchus offers a variation from other forms in the fewness of the nuclei which fuse (4 in one species) and in the tardiness of the fusion. he process of zygospore formation in Zygorynchus, according to GRUBER," shows some peculiarities which have not been observed in mucors heretofore. The zygospore arises at the point of contact between the terminal portion of an erect hypha and a lateral branch arising from the same hypha or rarely from a different hypha. At the point of contact the gametangia grow out from each hypha, Only the female gametangium is cut off by a wall at its base from the parent cell. Later a partly formed wall arises midway between the base and apex in the female gametangium, but this wall is rarely completed and soon disappears. The male gametangium remains in connection with the parent hypha. After the fusion of the gametangium a differentiated portion of the protoplasm of the male gametangium passes into the female gametangium, ca g with it 20-30 nuclei. The fusion of nuclei was not observed on account of their minuteness. The author believes that a multiple fusion takes place and that subsequently the fused nuclei divide to give the large number subsequently found in the zygote. He does not note the reduction in number observed by Moreau. The resemblance of the manner of formation of the zygospore in this form to that of oospores suggests that Zygorynchus, which in other characteristics corresponds with the mucors, is akin to the oomycetes.— H. HASSELBRING. Cecidology.—A very interesting and valuable contribution is a study of a citrus tree cecidium caused by Sphaeropsis tumefaciens Hedges by HEDGES and Trenny.4 The organism was first isolated from lime tree knots from Jamaica in 1904. The knots vary in size from } to 3 inches, and are usually more or less spherical; they are light in color and smooth when young but become black and furrowed with age. The interior of the knot is hard and compact, while the outer part is soft and crumbling in character. They are frequently more or less covered with typical witches-broom growths. They occur on both old and young growths and at any season of the year, and eventu- ally cause the death of the plant. The mycelium may grow in any tissue, but is confined to the intercellular spaces, but unfortunately the authors have not given a discussion of the structural characters of the malformations. The fungus penetrates the wood for considerable distances beyond the point of inoculation, thus making pruning an unsatisfactory treatment. Pycnidia 13 GRUBER, E., Einige Beobachtungen iiber den Befruchtungsvergang bei Zygoryn- chus Moelleri Vuill. Ber. Deutsch. Bot. Gesells. 30:126-133. pl. 1. 1912 14 HEDGES, FLORENCE, and Tenny, L. S., A knot of citrus trees caused by Sphae- ropsis tumefaciens. Bull. no. 247. U.S. Dept. Agric. Bur. Pl. Industry. 1912. 1913] CURRENT LITERATURE 407 may or may not be produced; spermogonia are produced, but perithecia and conidia have not been observed. Another important contribution to our knowledge of American cecidology comes from CosENS,'s of the University of Toronto. After a brief review of our present knowledge of cecidology, he discusses the results of his own investi- gations. The subdivisions are arranged with reference to the insects causing the galls, but the discussions are primarily botanical in character. The results of these studies confirm much of our previous knowledge and make valuable additions. The Eriophyes galls show a well defined series from simple indenta- tions to well developed pouches, and from modifications of epidermis only to the palisade and mesophyll also. The modifications are those of degree rather than of kind. In the hemipterous galls the stimulation is from one side and is disseminated equally in all directions. The lepidopterous galls are dnaalieed as a simple type. The glands are larger than in the normal tissues. The dipterous galls are extremely variable in degree of complexit and the glands are very abundant. The sawfly galls of the Hymenoptera show a great tion of tissue, with but very little differentiation. Tannin was especially abundant in the eptdereix and bast and probably serves for the 1 of changing starch to sugar, which acts on the starchy saber Sete of the nutritive zone and accelerates the rate of their change to sugar. The material thus prepared supplies nourishment for both the larva and the gall. The protoplasm of the latter is thus rendered unusually active, since it receives an abnormal quantity of available food material in a limited area. The hyper- trophy and cell proliferation and probably also the appearance of vestigial tissue or other primary characters are the response of the protoplasm of the host to the additional food supply.” The author also says that it is not neces- sary in all cases for the stimulus to be applied to the cambium, but that it may be applied to any actively growing tissue; that this stimulus acts on tissues at considerable distance from the point of SS that certain inquilines have the power of gall production to some exten A very brief paper on pistillody by Lewis shows a necessity for botanists to give more attention to the recording of the abnormal structures in plants. In this case both the anther and the filament were inflated and bore ovules, the anther being modified into a sessile leaflike structure with a stigmatose edge. *s CoseNns, A., A contribution to the morphology and biology of insect galls. Trans. Canadian Fast, 114:3297-387. pls. 13. 1912. % Lewis, I. W., Pistillody in Argemone platyceras Link and Otto. Torreya 12:85-88. 1912. 468 BOTANICAL GAZETTE [JUNE Among the important foreign papers which are of some interest to botanists are the following: —Two systematic papers by Hovarp” in which the author gives descriptions and notes based on the characters of the galls. Docters VAN LEEUWEN-REIJNVAAN® continue their very valuable descriptions of the galls of Java, describing 99 species. These descriptions are purely botanical and in most cases the species is not named, but is placed in such genus or family as may be indicated by the external characters of the cecidium. This is therefore merely the record and description of certain types of cecidia found on certain species of plants and becomes an important starting-point for future workers ——MEL T. Cook. Motile isogametes in the Chytridiales.—KusaAno” has demonstrated in Olpidium Viciae, a new species — on Vicia unijuga, that the free swim- s in the lower green algae. Similar copulation was costae inany years ago ‘a Fiscu in Reesia, which is closely related to Olpidium, but his account has not been generally accepted. KUSANO, however, not only followed the zygote to ase but traced its cytological history through to the next generation of zoospores. Conjugation, which seems ge occur only during the amoeboid rvais between active swarming, appears te be = ‘by a contact stimulus. There is a slight physiological that not all of those which come together. appear to have a sexual affinity, although one of such a mismated pair may often fuse with a third which comes into contact with them. Zoospores from old sporangia which have been prevented from discharging by lack of water copulate more freely than those which have recently matured. Conjugated or unconjugated zoospores may infect the host, one giving rise to resting spores, the other to zoosporangia. After encysting on the outside of the host, the young parasite penetrates the cell wall and escapes into the cell, where it is freely carried around by the rotation of the host cytoplasm, until it finally comes to rest near the nucleus. Though naked until nearly mature, it never undergoes amoeboid deformation as in Reesia and Monochytrium. The zoospores are discharged through very short wartlike exit beaks, of which four or five may develop on a single sporangium, though only one functions. In its cytology this organism is so similar to Monochytrium as to make it evident that the two are very closely related, although in the latter the spores , Les collecti * Pate ae BE | . we oy 7 Ho toire d’entologie du Museum d’Histoire Neale de Paris: Vherbier du Dr. Fairmaire. Marcellia 11:11-46. 1912; and Galles de Mayr et Muller. Marcellia 11:107-114. 1912. *8 Van LEEUWEN-REIJNVAAN, W. Docters and J., Einige gallen aus Java. VI. Marcellia 11:49-100. 1912. 7 Kusano, S., On the life history and cytology of a new Olpidium with special reference to the pppbiasion of motile isogametes. ee Coll. Agric. Tokyo 4:141- 199. pls. 15-17. fig. I. 1912. 1913] CURRENT LITERATURE 469 do not conjugate until after infection. The nuclei of the zoosporangium divide during the growth stages by a process of amitosis like that figured by the writer in Monochytrium, but in the later reproductive stages they divide by mitosis, recalling conditions in Synchytrium and Chrysophlyctis. Fusion of the gametic nuclei in the zygote is delayed until the spring of the following year, the resting spores having of course matured in the meantime. Before they conjugate, however, they undergo a very peculiar process of budding by which large amounts of chromatin are extruded into the cytoplasm and central vacuole. The first division of the fusion nucleus appears to represent reduc- tion, after which the nuclei are multiplied rapidly until the maak sags spore ecomes a zoosporangium very similar to the temporary ities he demonstration of such a primitive type of sexuality in Olpidiun would oT from higher fungi under “the debasing influence of parasitism.” On the other hand, the facts so far brought to light do not give a clear ih et of the source from which these forms may have come. It is evident, only during the reproductive period. Kusano points out that this fact rules out the monoenergid Endosphaeraceae as indicative of the line of descent of Olpidium, though not necessarily eliminating the lower Protococcoideae in the region of Chlamydomonas. Now that cytological studies of the Archimycetes are beginning to accumulate, it is becoming increasingly evident that they represent not a single phylum, but a conglomeration of heterogeneous forms which have little in common except their apparent simplicity——RoBeErt F. GRIGGS. Physiological effect of Bordeaux mixture.—Aside from its fungicidal value, ietiereres suite has Deca reported by oS investigators to have a y activity of sprayed plants “This action has been further investigated by EWwerrt, who in a former reported experiments which indicate that, contrary to the generally pacsgtilt opinion, the physiological effect of Bordeaux mixture on the leaves of plants is detrimental. In the present paper Ewert™ reports the results e sists grown in tanks under controlled conditions, and in soil kept at a constant water content. It was found that almost without exception the yield of tu- bers, roots, and pods, and of total dry matter was depressed by a covering of WERT, R., Weitere Studien iiber die physiologische und fungicide Wirkung der seers bei krautigen Gewiichsen und der Johannisbeere. Zeitschr. Pflanzenkrank. 22:257-285. 1912. 470 BOTANICAL GAZETTE [JUNE Bordeaux mixture on the leaves. The depression of the yield increased with the strength of the mixture applied. Asa rule, the beneficial effect of the mixture has been ascribed to the shade-effect of the covering, which was supposed to protect the plants from too great an intensity of light. LEwerrt found that bean plants shaded by a light gauze during periods of greatest illumination gave a greater yield and retained their leaves longer than unshaded plants. A similar effect produced by a covering of Bordeaux mixture, he thinks, would be counterbalanced by the ill effects of the shade on cloudy days and the toxic effects of the copper. In the experiments with currants, it was found that spraying berries with Bordeaux mixture or dipping them into it increased their sugar content considerably. How this effect is brought about is not yet clear. This effect on the berries is so striking that a decrease in their sugar content, due to depression of the assimilatory activity resulting from spraying the leaves, can be easily overlooked. Two sprayings of the leaves with 4 per cent mixture resulted only in a decrease of 0.5 per cent in the sugar content of the berries which were protected from the spray. This decrease is attributed to the deleterious effects of ihe mixture on the assimilatory activity of the leaves.— H. HASSELBRING. Dispersal of seeds by ants.—SERNANDER* organized the disjointed and inaccurate data on the importance of ants in the distribution of certain seeds and fruits, and added a wealth of observations and experimental evidence upon this phase of ecological science. This particular kind of distribution he termed “‘myrmecochorous,”’ and showed that it was almost wholly due, not to the supposed mimicry of the pupa of ants by the seeds, but to the presence of certain oil bodies or “‘elaiosomes” which serve as food for the ants and hence cause their collection and storage. These bodies occur as various morpho- logical modifications or appendages of seeds and fruits, various types being distinguished. Some 120 plants were at that time listed as myrmecochorous, and evidence was produced that the activity by a single colony of ants for one season includes the transportation of many thousand seeds, some to distances of 15 to 70 meters. A recent article by Morton” calls attention to the important foundation laid by SERNANDER, cites the contributions that have appeared since that date, and summarizes the present situation of m cochory. The number of myrmecochorous plants has been considerably increased, although these studies have been almost exclusively confined to Europe. The associations affected are mostly those of woodland and ruderal plants. Morron concludes that ants have been acting as a selection factor for such plants at least since ANDER, R., Entwurf einer oe der europiischen Myrmekochoren. oo Vetenik. Abad. Upsala 41: 22 MorTON, FRIEDRICH, Die acs der Ameisen fiir die Verbreitung der Pflanzensamen. Mitt. Naturwiss. Vereins 1912:77-112. Reprint by author, 1913. 1913] CURRENT LITERATURE 471 the Tertiary age, and that the center of distribution of woodland forms has been the forests of central Europe, while ruderal myrmecochorous forms have radiated from the Mediterranean region. The elaiosomes, in his opinion, have originated in many ways quite aren of the purpose they now serve as factors in distribution—Gro. D. FULLER Anisophylly.—In Strobilanthes onisophitus Ficpor,?3 experimenting to discover the cause of the development of isophyllous shoots, is satisfied that it is a reversion to juvenile form cetth eciive show no anisophylly until they have attained considerable size, and he thinks that it should be possible to prolong isophyllous developpient indefinitely. He agrees with BosHART* that good nutrition t phylly, but takes exception to his state- ment that anisophylly is to be explained through dorsiventrality. BosHArT’s in a more recent paper lays emphasis on his former points, such as the asym- metry of the growing point of anisophyllous shoots and the very slight effect of gravity and light. He thinks that the latter factor may affect ani- sophylly through increasing or ee the vigor of the shoot, the weaken- ing favoring asymmetry. He on the contrary, light exercising a direct influence upon the anisophylly 23 eden species of Selaginella and Lycopodium. Anisophyllous rosettes in various species of Sempervivum have been experi- mentally shown by DoposcHec-UHLAR™® to result from an inclination of the stem axis toward the horizontal, but whether the response was effected by gravity or light he was unable to determine. The anisophylly seems to disap- pear toward the close of the growing season and to be renewed early the follow- a spring. The phenomenon in nature is closely associated with the crowded ouping of young plants about the te rosette in the characteristic multi- riicatin by offshoots.—Gero. D. FULLE Morphology of Agathis.—Eames” has investigated the Kauri, the famous timber tree of the Australasian region. Our knowledge of the morphology of the araucarians has lagged behind that of the other coniferous tribes, so that this contribution is very timely. An outline of the results is as follows. Pol- lination occurs a year after the appearance of the ovulate strobili, and fertiliza- R, W., Das Anisophyllie-Phaenomen bei Vertretern des Genus Strobi- lanthes Blume. Ber. Deutsch. Bot. Gesells. 29:549-558. 1911. 4 BosHarT, K., Beitrige zur Kenntnis der Blattasymmetrie und Exotrophie. Flora 103:91-124. 1911 *s BosHart, K., Uber die Frage der Anisophyllie. Ber. Deutsch. Bot. Gesells. 30°527-33.. 19%2. 2° DoposcHEG-UHLAR, J., Die Anisophyllie bei Sempervioum. Flora 105:162-183. IQI3. 77 EaMES, ARTHUR J., ‘aia estima of Agathis australis. Ann. Botany 2721-38. figs. 92. pls. I-4. 472 BOTANICAL GAZETTE [JUNE tion 13 months after pollination. The numerous archegonia are scattered over the broader micropylar portion of the gametophyte. The pollen grains germinate in the axils of the cone scales, before there is any differentiation of amicropyle. The pollen tubes are long and branching and penetrate the cone axis, and also the phloem and even the xylem of the scale traces. The two sperms are somewhat unequal cells with delicate walls, and their nuclei are as large as the egg nucleus. The proembryo is three-tiered, the uppermost tier forming the suspensor, the middle tier the embryo, and the lowest tier a pro- tective cap. The cone scale is said to be structurally double, representing a combination of the bract and scale in Abietineae. It is concluded that the araucarians represent a highly specialized branch of the Coniferales, and that Araucaria is probably more ancient than A gathis.—J. M. C. Anatomy of Botrychioxylon.—Scorr® has described in detail the anatomy of Botrychioxylon, one of the paleozoic Zygopterideae. As in all the members of this family, a true pith is absent, the primary wood of the stele being intermixed with much parenchyma. Around the whole primary cylinder, as well as around the diarch leaf-trace, is a wide zone of secondary wood, a condition rare or absent in most of the family. The petiolar bundle resembles somewhat that of Dineuron or Metaclepsydropsis. Because of the unusual development of secondary wood, Botrychioxylon is considered by its author to approach the living Botrychium more closely than has any previously described form, and to present evidence for the affinity of the Zygopterideae and Ophioglossaceae. This conclusion is in harmony with that general theory, now the subject of much dispute, which derives the true pith of modern ferns from tissue which was primitively stelar—E. W. Srnnorr. Fertilization in Gagea.—In Gagea lutea® the usual double fertilization is the rule, but occasionally both male nuclei fuse with the egg. Another appar- ently unusual feature is the inclusion of cytoplasm between the fusing nuclei both during the fertilization of the egg and during the fusion of the polar nuclei. The included cytoplasm soon disorganizes. This is the second record of such a cytoplasmic inclusion, the first having been made by BRown? in his study of Peperomia. The dispermic fertilization and a study of the literature of chromosome numbers leads NEMec into speculations upon the origin of muta- tion.—CHARLES J. CHAMBERLAIN. * Scott, D. H., On Botrychioxylon paradoxum, sp. nov., a paleozoic fern with secondary ene Trans. Linn. Soc. Bot. 72373-3890. pis. ar. 1912. 29 NEME , Uber Befruchtung bei Gagea. Bull. Internat. Acad. Sci. Bohéme ne ae. Jigs. 3° Brown, W. H., oy dened of material between nucleus and cytoplasm in Peperomia sintenisii. Bot. Gaz. 49:189-194. pl. 13. 1910. GENERAL INDEX Classified entries will be found under Contributors and Reviews. New names and names of new genera, species, and varieties are printed in bold face type; syno- nyms in z¢alic. A Acai Acarospora het 3945 chlorophana : 5; thermophila 394 Acids, toxic 409 After i i . at Agaricaceae Ag. otis ‘morphology of 471 f : Alga ~ osteel arbuscula \Inus, a8 tubercles of 254 f Amelan 333 Ames, ‘haan 307 Ames, O., work of 92 Andrews, F. M., work of ; 331 \ngiopteris, vegetative reproduction in 262 Angiosperms, earliest European 335 Anisophylly 471 Ants, dispersal of seeds by 470 Aptiana 3 35 Arabis Menzies lata 374; oa 3743 pedicellata 37 Arac Reaeacetis brasiliensis, or peamptle of 97 Araucarians, evolution of 1 Araucarioxylon aan Arber, E. A. — “The natural history al” of c as gesagt 437 eter 31 e cause of leaf 4: Atanas revolving table yo stand- ardizing 249; standardizin B 7 W. Lawrence, “Cotton plant in "33 Basanacantha grandifolia 436 Baylesia 94 Bayliss, Jessie >; ae of 176 Beccari, ., work of 9 Begon serra oo ily M., work of 171, 172 Bertrand, G., work of 88, 89, 90 esa Bissell, C. ear work 92 Bitter, G., work of 9 Black oe: vTayering z 452 Blake, ork agit Blastenia a crhaehs Bog waters, rene a a peat hairs 314 Bolelia brachyan Bordeaux se viulaaleal effect of Boshart, K., work of 407, 471 Botryc chio xylon, vensinrand of 472 Botryopterideae 263 Jottomly, W. B., work of 255 Bower - 38 1 rachyoxylon ax¢ , E., work i 92 d fend. Kk. | Wor rk of 9 1 rakes ee, T. S. "work of 92 rauns, a} ork of 9 ; wok f ; ., work of 92 rown, Nellie E., work of 257 rown rots, panes rane of 95 r ork ia dis Burlingam: ts Lancelot 97 Burtt- Dey, J., work of 92 Butler, E. J., w ork of 92 Butters, F. K “Mi shrubs” 3 innesota trees and Cc Calceolaria 332 Calcium-magnesiu 96 Caloplaca ean sae "mora 396 Calyptrella cycliophylla 4 Candelariella a cerinell 306 Cande Capitularia pte Tex 93 Caryocar costaricense 431 473 474 Castilleja 93; ectere 380; curticalix 380; fasciculata inverta ae miniata 379; rhexifolia ubesie 58 Cedar, habitats of the red 2 orchids a 3323 aay plants from 431 Cereus 3 Chalaz on evolution of ig mneoigilormme Charles J. ce T4i, 254, 62, 403, 462, 472; work of 462 China, plants of Chytridiales, motile isogametes in 468 Citrus trees, knot diseases of 407 un- oy P ibintisota trees and ° Clibadium Climax forest of =~ Royale 1, 115, 189 Clintoni 82 Coal, ‘catueal history of of 170 A. 4 Cockerell, T.-D. Collin: s, G.N., si of. 261, 404 C alins, s F ranklin, “Keys to trees” 339, Collins, aT. S., work of 93 Conard, <= Coniferales, _— tracheids in 56 Contributo: Ames, Adeline 397; Bower, F. . 384; 2 vey i re = 973 Chamberlain, C. a 04; id 254, 262, 403, 462, 472; Cockerell, T “DCA: 460; Conard, H. — 80; Coo Jk, M. T. 259, 260, 261, 262, 263, 264, 330, 336, 402, 462, 463, 471; Cowles, H. C. 328, F. 408; Hassel- ‘ 3. 300; ; iy nig ; S. 421; Ricker, P. L. 461; Rigg, G. B. ; : aoa 258; Sinnott, Be W433 Smith, H. H. 458; Smith, INDEX TO VOLUME LV [JUNE D. 431; Snow, Laetitia M. 45; = Anna M. eee pion W. C. r, W. L. ; Transeau, E. N. 66; Wilson, F. H 409; Yaman- ouchi, S. 74 oe Mel T. 468 ooley, J. S. 421 Cooper William S..1, 115, 189; work of Coeeoea d, E. B., york of 93 Cordia gualanen 438 an i 171, 172, 259, 260, 261, 262, 263, 264, 330, 336, 402, 462, 463, Covle es, Henry . 328, 407 Craibiodendron Crassulaceae, em eneye sac of 258 Crocker, William 167, 253; 337 Crodelia esto 257 Cyathea Lb seciatilony 93, 463 D Dalea arborescens en Lg seesaw 3133 californica 309; Em 3006; ne hns sonit 30 a "mali 302; pis ryt 3 poly- te 2 305; 5 mee indersti 308" 9 holiii "spin Dirsuhine, Otto v., work of 259 Darling, CA. , work of 331 Davidson, A., work of 331 Deam, Cha rles C., work of 331 DeFraine, E., wo ork of 175, 261 Delaware Coast, plant associations of 45 Delphinium megacarpum 373 Diaporthe 93 Diastase, malt, effect of chlorides on 265 Dichothrix 333 Dicotyledons, phloem of 236 Didymosporangium repens 94 Diels, L., wo — of 462 Dingler, ork of 334 Dioecism i in Eplpens 256 Diplasiolejeunea 93 Discosiella $33 Dia. H. N., work of 93 Dodge, B. O., aoe of 331 tee cheg-Uhl ar, J., work of 4 ark aay brachyan tha 382; ieible Hor, ee W., vies 2 o Drainage, cold a Drummond, J. R. oe of 332 1913] E Eames, Arthur J., work of 471 East, E. M. 177, 404, 405 Imer, A. = i Patt of 93 Engler, A., work of 462 Ep es dra ai ~ vegetative reproduction in 439 Epigaea, apa in 256 Epilo — Erica Brigeron ‘tkoensis 382; poliospermus latu: iescatye S 04 Buphorbiaceae 463 eae a gigaspora 94 Evans, A. W., work of 93 Boat i; work of 95, 469 F Fairy ring fungi 176 Filices ‘j st Cl ores ecw a Isle Tpovale I, 115, 189 ler, “Gas ee 96, 175, 176, 253, 257, 58, 260, oe 328, 320, 334, 402, 408, 452, 470, 4 Fungi, fairy ring ie metabolism of 85 G ere fertilization in 472 ae major - seitaerset ‘pureum 376; caespito- sum post 376; — 376; gracile 37 Gibellula 3 einag nT 434; stenocarpa Ginkgo, pea by 251 Givler, J. P. Gjellerupia fg Gloeotaenium, life history of 66 INDEX TO VOLUME LV 475 Gliick, a. ““Wasser- und Sumpfge- wichse 1/398 an, J. M. 92, 254, 331, 332, 402 Griges, Robert F, 468 E33, wick of 331 Grier, E., work of 406 um, effect on transpira- Mn 421 Gyrophora reticulata 394; rugifera 394 H genrorwrad ia ogg ca Pflan- 02 Harper, — “sf 3 po ses L. ‘Le n, Max, «Protigty enkerne”’ 254 H. 92; a og 257, 463, 469 yi. C. oe of 332 chee a Hedges, E. * ile of as 406 Heimerl, A., work of 9 Heinricher, E., « Parasitischen Samen- pilanzen”’ 252 Heller, A. A., work of > 332 pers Ansel F. 2 Hill, ., work of 261 Hilleri Hodieania Conrad 244 Holden, Ruth 56, 335 Hooker, Sir * Jone Dalton, sketch of 384 Horkelia ben “id 3 ouard, C., k of 4 Howell, Thomas, —_— of 458 Hutchinson, J., work o ybrids, ra i na 405 Hydrodic Ti 4 Hi hophylincee Q2 I Illinois Academy of Science 403 Indiana Academy of Science 330 476 Inheritance in maiz Insects and plants, fhonaabogteine of 462 Isle Royale, climax forest of 1, 115, 189 J Jamaica, lichens of 332 ta : t, Charles, “Le Volvox”’ 403; work f 462 Ja villier, M., work of 88, 80, Johnson C. 168, 170, nes oie of 172 A. G., work of 3 Jon s, W. 2 “De a iaiteotililiche Giteratur” 463 K Klebs, G., work of 334 Kneucker fg em of 93 Knight, Lee Knot fees of ris trees 407 or gr Krause, al work of 04, 462 Kusano, wie ” work of 468 L Lambert, F. 2” tag of 94 ee W. iG William t ars of 262 Lauterbach, rome “a rk of 462 Layering in woe pgs 452 Leaf fall, cause of 1 accion melanophthalma 396; 396; thamnina 395 Lecidea atrobrumiea 303; plana 394 Lendner, ‘A Ise of 465 rubina % W., ak of 467 Lichens 92; antarctic 259; . a op firming paba Lignier, Linnaeus, sketch 7 se 2 Lipman, Chas phe ngston, B. '¥,. - ek cl he 264 w, Oscar, W ork of 96, 1 geile 93, 332 M Macbride, J. Francis 372 Macfarlane , J. M., work of 94 ensen, B., work of 04 rapeseed Moorei 141 INDEX TO VOLUME LV [JUNE Maiden, J. H., work of 94 Maize, inheritance in 404; origin of 261 Malt-diastase, effect of chlorides 265 ? ] McLean Meliosma ag -ppaen i 432 Merrill, E. D., work of 94 Mesoxylon 17 Metabolism of fungi 85 iller, F. A., work of 331 Mitlacher, Wilhe ne ase offizinellen Pflanz und Dro; Molise, eas itt cachitende Pflanzen” Gone F., work of es Morphology of orchids Morton, Friedrich, work, 470 Osses 93; ecology of Mucors 463 Murri = W. A., work of 332 Musci 463 Myrica, root tubercles of 254 N Namyslowski, m Pidges of 465 Nawaschin, S., k of 94 Neopaterso Neutral fy cect of 174 Ni Nichols, George E. 2 Nicotiana, vice rade inheritance of Nouhuy Nuclei of Protas 254 O paler “pemgger vascular anatomy of 262 sips po , a protocorm of 155 Opu Oranges,