0154101 | UNIVERSITY | TORONTO il ce) ™ —_ oO nas sae ran Lect sad to zoe belts ate fee Chae as Fh igri Bay pee ane Aagacyh pees DFP e See ike tip wr biaete cepeges Sh ery sirr eit t per ees | Seppard eet ae LENE Ts O03 A Gta ES ghee 24 fo hve reser ay opts eae Orit sine or ake PEs Fey) Saba xs popes adh eas Pests Bee spe tees LBs g eA So 25 gid fA -t peed ety Sirheet Seabees ays tor Sg meta ade eho8e migeerd Fabea: begiy Pegi fy : kita tata gt Len te | Babar yt pes O18 £5 the ee ‘ tee aes, Lape 3 Sp o5 9 $ + #: Tsisdpit cs ewe f oF aaa f : i 4 ; 4 Sor p rt k WeAt ar: Tiel gt b28 «Breet er FRPGESE LE Nesey Abteee iets 5A Sats £ : 5 J : ads a i A s 3 Pave Pat Feit i ‘ f 2 : 82 ERO AG | ste thitreorantes rates a4 Wea pesbe a hess es ts a iaurotks es ‘ nial Vy, | t fish ih A a en ; Mae ; nr Y “ i" ’ i oty » a nel Pi A [ | age ' . i +f wv i oe Eon i) i Ps : ¥ ' a « , ‘ a j a 7 A A ' a} a ie i) b; i i 5 , ‘ ' ; Vi 4 7 oo ¥ 9 ; , . { / « Uy i } } ie biti i By rye Woe aaa ** y 6 a Ye \ A ¢ a ee — Digitized by the Internet Archive in 2010 with funding from University of Toronto http://www.archive.org/details/influenceoflightOOmacd 4 , sil rey? oie Se! Page i i : ' € te) ‘ i ; es , qi A ih 4, 7 } ° . 4 ¥ @ J a i rs u Ah rue « a 4 : D > b ae ‘ i Ch % ns 7: : 1 ' a a. 4 : | H i 4 $ 6 ‘ eS ‘ . i] ¥ Hy ned ’ | a) “i i 4 j ¥ t @ * i i! j on » mM ’ . 7 | .s ‘ Ary ‘ j fi 4 4 ‘ on ‘4 " yen Oui re) ed p> a Uy 7 , a at ‘od a MEMOIRS (les OF THE NEW YORK BOTANICAL GARDEN Vier. LP. THE INFLUENCE OF LIGHT AND DARKNESS UPON GROWTH AND DEVELOPMENT BY SewEL TREMBLY .MACDOUGAL, Pu.D. ISSUED JAN. ZO, 1908 i~ EEE ENELUENCE OF LIGHT AND DARKNESS UPON GROWTH AND DEVELOPMENT BY PaniEL TREMBLY MACDOUGAL, Px.D. PUBLISHED BY THE AID OF THE Davip Lypic FuNb BEQUEATHED BY CHARLES P. DALY. NEW YORK 1908 sO (CRe PRESS OF THE NEW ERA PRINTING COMPANY LANCASTER, PA. HON Se PREFACE. The results described in the following pages were obtained by a series of experimental observations begun in 1895 and continued until the close of the year 1902. Originally designed to analyze the phenomena of etiolation, the work has naturally led to a consider- ation of the more general relations of the plant to light, and it is believed that some important additions to the knowledge of the sub- ject have been made. The chief results of value have been obtained by long continued confinement of the etiolating plants in dark cham- bers from which light was entirely excluded. The author has received material assistance from his students and colleagues during the seven years over which the investigations extended. The description of the etiolation of Oxvalis and Sarrace- nia purpurea is largely drawn from examinations of etiolated speci- mens made by Mr. Wm. B. Stewart. A number of botanists have rendered ‘notable aid in the interpretation of some of the morpho- logical facts presented. | The illustrations are from drawings made from the actual objects or photographs, by Miss Alexandrina Taylor and Mr. August Mariolle. D. T. MacDouGAat. New York BoTANICAL GARDEN, Jan. 10, 1903. ‘tar TABLE. OF (CONTENTS: THE INFLUENCE OF LIGHT AND DARKNESS UPON GROWTH AND DEVELOPMENT. HIsTORICAL. REcorD OF INVESTIGATIONS. Pace. MMMMIEECIOO)) 2 50 oe baton acon cone ycwbnenennpecetnmesvennestecealncneg cinncseee I MEET 727)... ce an eevee we ceantnnes se cen ececiindenainies suv detncrany siiiaad ena I MMIC L754)... 52 osccne conven sensucnseesahnngenner seis ones cleasnymncnainedessins I BEEP 770) ce. cen an vencn cu usnan oat ooehelerenceatsnsices os ve sedanmadus tignaea a= I BirraAAMC! (1758)... .....ecoesnesese cccemesaesonnanegeccsstetcerscdess oecoeers 2 BREMEDIer (1752, 1800) ..........00. cececancncerececesessersescenereterreeces 2 MUPMURIEEIEL U7 E2 ) ova ces ne 2 veice nose sion tis vviiv clnmepenmnc sents s om aagheviest crac ances 2 MMESAUSSUTE (1804) ..........0.2..0ceceeseenenreneecccersceene Sencrecenene ces 3 Mee@andollic, A. P. (1806, 1832).......ccsceccscswabenaasccdcserweuecsnes ens aA MMEA(GL GO)... 5. cee ese ecnn es conve rad cavsleccnsebaiene denen sonsneneshenen rae cces 2 Mammen |. Es. (1807) .....005..ceccenpantisterstnet ani rercessavemsateacteoenseness 4 BEB O7) 2.2.2 .20..05 ces cecenceccecaectnneeseauewsesersecesesennmance serene 4 Mise (1O4T)... po 2... seccceccenseeececter see caersenenennenecentecnor cers aceon 4 MVC TS1S )......-2c00- ence sceesenteentecceeoecceansectececcneetscettersenecses 4 ISAM... occ cs ns, 22sec euneeesbeouenaeersecerccneeansemsteomeansnsneoerascsade 4 ietees Bi. (1825 )-.... 6. 00s enon. conc eescrenereenstanacaecssseehencrecessez cececs 5 Montagne (1841) ........:ccececeercaececeenreseeesceuecssecsenececncsseresseces 5 Mmm (TS52) ...220022.0.0ccecscscee scons seccnnem awatesnerstee veenecerainces 5 MVEINE (1846) 0.62.50 ceoccacedeevedetteneesecenener ses sncenera rapecesnnaneees 5 PPOMOGED (1851 )......5cc0cccceccecnt sere ercemasnscasatencimeres cones pls eter 5 Beenniits, J. (1943) ....xtesceeeseecsnaeeecneseneraua Sean cercstereccesnecsseee 5 B¥CHary (1863) .....-.0--c2.ccscaceneer ect nenseerancecusens Geerderneceracnscaees 5 BEE TS42 )ic..--ocbannnrce nee cre ren ererss+crasepsentenseaeecseseecnaneescesscee? 5 BGACOMET (1844) .22-- a ecscencsecsccaees wn slonmdemenmscssenesee eecirhoreceesnas 6 Miraiper (1544) .....-..-.2c0ccensee weeuescceaan Gace al eeceressensebecewes cn anes 6 Mairochet (1842)....-.....2. 00200 seseeeconeenencoteacnseneeaenatineanaesneness 6 Carpenter (1848), ...........ceceeteeeceseseerenseneneenecteeeeteescccsesenaees 6 Biel, A. (1856) o.2.c2. « +b tes elete tet eaete eet aa 34 Neljubow (1901 ) s..0ese.scee+esceggensin sane ss elven «men 7nnimaeesan se enesiia 34 Schulz (LOOT) ve. cectews sweiie a . sete eea eee eer 40 Amorphophaltus Reuters, ure . 220. 20h init veev ncn eee ee 40 Aptos Aptos (Ts) MacMs: vc ccccicsetee cscs chtace ses cx@tet eee 42 Aplectrum sprcatum (Walt.) BuS.P o.s.:..0de:.ce0 cena «ee 46 Arisaema Dracontium (Lis). Schott onc.c. tk sssexese see eee ee eee 48 Arisaema triphylla. (Vi.) VOLt.....0.)vedsacca0s «eek oye eee 50 PAL TSLOLOCRIG SPs isicis asta aiawcigisle cin vos «'oie ain: aed dest eee = Bee er re: LAN PLGA STO SEC LATA Aon ie ary van cio Serge eGR lisa vestaidheeeeb eee re Asplenium platyneuron,( li.) Oakes. 2. nse: 0. cess eset oa 75 Aster AtvartCatus Livenescaetin css sacs saasmeine sacle seehaston ee ee 78 Baccharts halimi fared Vis vis 5s00%a enna eieass anaes Boats eee ee 80 Bicuculla cucullarza (1G.).Millsp........2-..00..0s+eesses eee dee eee 80 Botrychtum obléguum: Nan, «0... 0..05:0s0 tee oc.2s icine nctee eee eee So BOLE VOLLD 10s NAATWic won, dole xsed uses ee eee ae ree ee + weininn tiie niate ola oe ete ea 82 BY ASSUCE COMP OSULIS: Visierinces sve vasas aSaevelsenew.tes «cee eae 84 Caladium: esculentum N Cnt... dhasessccn 412s 5escncwseeeeee ee 85 Calla (cultivated) 2. iis winiosene seaened nace on went acca ek <.ee 86 Calla Palustris Vis. .cdeeno.scieis0e vandhi an iek otis on ee ee 87 CamMassid =" QUuamagsed Spo. .dsnaseueencesenksus 4-0 -susnchhth eee 87 Canna’ (cultivated) «2405.0. dsen00dgnnse denotes naeas oe 88 Castanea dentata (Marsh) Borkh. ......cs.c0c..-+2-2:-s00sed gI CoCUta MaACUlata NG. syoccisensaens ss 20% cehlavassetas sone cahanes cel e e 93 Claytonia Virginia Vass viv. cass sinncenshsetiui-sadh elvan ee 94 Gocos: nucifera. Latss it) aid ved one cacbose RHEE coe en ee eee 95 Cox Lachknymaz Jobe Mn cscsviveis .acaisterubeeass5eic1sses ah eee 97 COLOCASED SP vi wos saieiine sh veiene annie corse soko Sh eee Ee 97 Cornus alternifolig Vvn..t. sca tve..c.ssceodst et dese ee 97 Cyclamen Sp... svcivusensdsncsasentissvsssvsonyneisae devise 100 Cypripedium montanum Doug). ............ vais die Ube site eles 2c Ree 101 Delphinium enaliatum Nit. .....0.0ct- - a | i i ie | a ‘p a : ® AN / { ¥ _ x j I i ; ms . at tT -ofi " cf | | : Ng a ° ye be 1 ‘ ee | ata ohh a ve, , my " 4 7 ec. an) hee) ao SP te 3 v4 ; Mr ane Aig F al a ; 7 el va : ie + | ‘ ~~ « ~*~ ing _ f “ry (ade “ es ° ~ : ‘ is THE INFLUENCE OF LIGHT AND DARKNESS UPON GROWTH AND DEVELOPMENT. HISTORICAL. The more apparent features of the behavior of plants in darkness must have been a matter well known to cultivators from the earliest times, but a conception of the influence of light upon growth and form seems to be a distinctly modern idea. John Ray appears to be the first botanist to make mention of the more apparent features of etiolation, and of the relation of color to illumination.’ * The quantitative effects of illumination of various degrees of intensity was known to Hales ina way, and he saw that diffuse light did not permit or induce normal development as he says: ‘* Beans and many other plants, which stand where they are much shaded, being thereby kept continually moist, do grow to unusual heights, and are drawn up as they call it, by the overshadowing trees, their parts being kept long, soft and ductile.” Hales also made the observation that plants become heavier at night.?, So far as may be learned from the records consulted, Bonnet may be designated as the pioneer in actual experimental investigation of the subject. He carried out a series of tests upon beans, peas, and branches of the vine, from which it was seen that elongated internodes and small yellow leaves were produced in darkness. Etiolated plants became green after exposure to illumin- ation for 24 hours. Green leaves placed in darkness did not blanch, but fell from the stems. The wood of etiolated stems did not ‘*harden ” and cuttings from etiolated stems could not propagate the plant.® After Bonnet, Mees may be named as having carried out the next important experimental observations, which covered a large number of the phases of the question still under discussion. Mees saw that some seeds germinate in darkness as well as in light, that red color 1Ray, J. Historia Plantarum, 1:15. 1686. Also in imprint of 1693. 2Hales, S. Statical Essays, 1: 334. 1727. Also p. 336. Ed. of 1769. ’Bonnet, Ch. Usage des feuilles, p. 254. 1754. 2 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN, is formed as usual in etiolated leaves, that aquatic plants may be etiolated, that perfect seed formation does not occur in darkness except in subterranean plants, that flowers which open in darkness perish more quickly than similar ones in light, that growth is more rapid during the first stages of etiolation, and that etiolated plants take up and transpire less water than the normal.* It is remarkable that these earlier observations agree almost point by point with those which will be described in the concluding section of this memoir. Duhamel recounted the observations of Bonnet in 1758, but it can not be learned that he made any independent experimental investigation of the subject.’ Knowledge of etiolation was notably increased as a result of Senebier’s observations, which were first published in 1782. Sene- bier found that etiolated stems of the bean were greater in diameter and developed more hairs than the normal plant. The epidermal cells were seen to be more irregular in outline than those of etiolated plants, and were separated from the underlying tissues by smaller intercellular spaces, and the pith was greater in amounts in etiolated plants. The emergence of the flowers of certain monocotyledonous plants in normal and etiolated specimens was thought to be depend- ent upon qualities of the sheath induced by etiolation or illumination. Peduncles were seen to undergo excessive elongation in darkness and some changes in colors were observed. Mosses were seen to blanch when placed in darkness for long periods.® Twenty-eight years later Senebier gave a comprehensive sum- mary of the subject, in which he noted minor observations by Lin- naeus, Humboldt, and others. He made the first estimations from which it was seen that the dry weight of etiolated plants is less than the normal, and formulated a hypothesis to account for the phenom- ena of etiolation, which asserted that the basal or primitive color of plants was yellow, and that coloration was due to the fixation of car- bon and elaboration of the carbon compounds. The absence of illumination prevented the assimilation of carbon dioxide and the construction of coloring and other matter.’ ‘Mees’ observations were published after his death by Van Swinden in the Jour- nal de Physique, 6: 445. 1776, and 7: 112, 193. Duhamel du Monceau. Des plantes étiolées, in La physique des arbres, 2: 155. 1758. °Senebier, J. Mémoires physico-chimiques, 2: 51-116. 1782. "Senebier, J. Physiologie végétale, 4: 264-308. 1800. MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 3 A number of scientists made observations of various kinds upon the relations of light to plants in the closing period of the eighteenth century, which resulted in the discovery of the simple elements, and the foundation of chemistry. Attention was chiefly directed to the evolution and absorption of gases in darkness and in light, but inci- centally some information was acquired as to changes in form as induced by various degrees of illumination, 01 by darkness. Tes- sier ° tested the formation of green color in red yellow, and white light and of illuminations from lamps and the moon. Some strik- ing effects in phototropism were obtained. Senebier exposed plants to isolated portions of the spectrum, and to illuminations of various intensities, finding that growth was more rapid in violet rays than in red, and that white light was more active than any of its con- stituents. De Saussure’ concluded as a result of his own work and the results of others that light was without effect upon growth as manifested by germinating seeds. DeCandolle” describes some work done by him upon etiolation in 1799, in which he notes the blanched appearance of the undeveloped leaves formed by etiolated seedlings of Szxapzs album, Lepidium sativum, and Miagrum sativum, together with the phenomena attend- ant on the excessive elongation of stems, which ensued in darkness. Several years later he gave the matter somewhat more comprehensive treatment in his text-book on plant physiology. In the latter essay he sets forth that sunlight increases the suction of roots and causes transpiration. Cessation of illumination, as in etiolation, stops trans- piration, while absorption continues and the plant becomes highly charged with water or ‘‘hydropique.” The formation of coloring matter in flowers in the darkness was observed. Non-green organs were supposed to be but little affected by etiolation. He also made partial etiolations by thrusting the tips of branches into dark chambers, although he was not the first to try this experiment as asserted by G. Kraus, Bonnet having made similar tests a half century before. Link" reported that etiolated shoots were pale in the earlier stages 8 Tessier. Expériences propres a dévelloper les effets de la lumiére sur certaines plantes. Mém. 1’ Acad. d. Sc. Paris, p. 133- 1783. 9De Saussure, Th. De l’influence de la lumiére sur la germination. Recherches chimiques sur la végétation, p. 21. 1804. 10DeCandolle, A. P. Expériences relatives a l’influence de la lumiére sur quelques végétaux. Mem. Math. et phys. Inst. Nat. Paris, 1: 332. 1806. (Presented in 1799-) 1 Link, D. H. F. Grundlehren der Anat. u. Physiol. d. Pflanzen. p. 291. 1807. 4 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. but became green later, no doubt due to defective methods of ex- clusion of light. J. E. Smith” records that when light was admitted to leaves through glasses of different colors, the plants became paler as the glass approached violet in tint. He reiterates the mistaken idea that blanched plants become green when exposed to the action of hydro- gen. From a consideration of currently accepted descriptions he concludes that light acts beneficially on the upper surfaces of leaves, and hurtfully on the lower sides, hence the upper is always turned toward the illumination. ; DeCandolle * also exposed a number of plants to the light from six argand burners, which was insufficient to cause the release of oxygen, yet it was found that this illumination would cause the for- mation of chlorophy] in etiolated specimens. Ré" used the term ‘‘clorosi” to denote the blanching of plants when deprived of light, as distinct from the modern usage, and re- lated that many ‘‘salads” were treated to induce this condition (‘‘ asparagi, sedani, e cardi”). Knight was cognizant of the effects of deprivation of illumina- tion, and he developed a new method of culture of rhubarb in dark- ness and diffuse light in order to increase its succulence and edibility. His experimental results upon the influence of light upon the for- mation of the tubers of the potato have also become of great impor- tance in experimental morphology and physiology. Sir Humphrey Davy” made analyses of normal and etiolated material in which he found that 4oo grains of leaves grown in sun- light yielded 53 grains of woody fiber after being subjected to the action of boiling water and alcohol, and that an equal amount of etiolated material gave but 31 grains of ‘‘ woody fiber.” Poggioli” found that plants developed better in violet rays than in red, probably 8 Smith, J. E. AnIntroduction to Systematic and Physiological Botany. Pp. 206, 207. 1807: %DeCandolle, A. P. Physiologie végétale, 3: 1069. 1832. “Re, F. Saggio di nosologia vegetabile. P.23. 1807. Re, F. Saggio Teorico-Pratico sulle Malat ie delle piante. P.147. 1807. Knight, T. A. On a method of forcing rhubarb in pots. Trans. Hort. Soc. Lond. 3: 154. 1820. See also a selection from the physiological and horticultural ae published in the Transactions of the Royal and Horticultural Societies. 1841. '©Davy, H. Elements of Agricultural Chemistry. Pp. 208,209. 1815. " Poggioli, S. Opuscules scientifiques de Bologne, 1: 9. MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 5 referring to the greater elongation of the stems which ensues under such circumstances. Fries * as early as 1821 recognized the influence of light upon fungi and saw that many forms including the Hymenomycetes, and the Pezizaceae remain sterile and do not form spores when deprived of illumination, and that many variations in form, notably excessive elongation and branching, resulted from such treatment. Montagne saw that light did not exert the same influence upon the mycelium and sporophore, and Bonorden believed that the coloration of agarics and other fungi was dependent upon light. In this last conclusion however other mycologists were not agreed. The necessity of illumination to induce the formation of spores was also recognized by Tulasne.” The period from 1820 to 1842 is devoid of literature upon the relations of light to the higher plants in so far as the aspect of the subject in question is concerned. The text-books appearing about the latter date and preceding the wonderful renascence of botany under the influence of Sachs appear to ignore the observations of the mycologists and to assume that light could have an effect only upon green plants.” Beginning with the work of Payer” in 1842, several distinct series of investigations upon the relations of green plants to light may be distinguished. One dealt with the analysis of the values of the different portions of the spectrum in the formation of food, the pro- duction of curvatures and general influence upon growth. A second was devoted chiefly to the formation and activity of chlorophyl, the nature of chlorophyllary, synthetic and decomposition products. The third, which was first taken up seriously by Sachs, was concerned with the morphogenic influence of light and with all of the multi- Fries, E. Systema mycologicum, 1: 502. 1821. Also 3: 265. 1839. And Syst. Orb. Veg. 1: 212. 1825. 193Montagne. Esquisse organographique et physiologique sur la classe champig- nons. 1841. 2Tulasne. Fungihypogaei. P. 2. 1852. 21 Léveillé. Considerations mycologiques. 1846. Bonorden. Handbuch der allgemeine Mykologie. 1851. Schmitz, J. Beitriige zur Anatomie und Physiologie der Schwimme. Linnaea, 17: 475. 1843. De Bary. Recherches sur le développement de quelques champignons parasites. Ann. Sc. Nat. IV. 20: 40, 54. 1863. 22Payer. Mem. sur la tendance des racines a fuir la lumiere. Compt. rend. d. 1. Acad. d. Sc. 1: 1194. 1842. 6 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. fafious phenomena of etiolation. It will be unnecessary in the present connection to inquire into literature which does not bear directly upon the results of etiolations and the influence of light upon growth. Neither will attention be given to papers dealing with the more strictly morphological aspects of the influence of light upon ‘form, as in’dorsiventrality, etc. Payer, Gardner™ and Draper™ investigated the activity of chloro- phy] in various parts of the spectrum and also the general facts now. included under phototropism. Draper made cultures of peas in blue light and indarkness. He notes that seedlings under the latter condi- tion are pale yellow with no fresh leaves, and that a height of thirteen times the normal was attained with the etiolated plant apparently into a vigorous condition. Dutrochet” confirmed Payer’s results in the main. Meanwhile but little of the information gained by the late investi- gations found its way into the text-books of botany. Carpenter™ gave the substance of DeCandolle’s conclusions in 1848, and saw in the non-development of woody fiber and of secretions the most im- portant results of etiolation. The blanching of celery, sea kale and other plants was recorded, and it may be assumed that this treatment of salad plants was in more or less common practice at that time. He cites the following diverting illustration of natural etiolations, which is to be found in many European text-books of the period: ‘* It fre- quently happens in America that rain and clouds obscure the atmos- phere for several days together; and that during that time the buds of entire forests expand themselves into leaves. These leaves assume a pallid hue until the sun appears; when within the short period of six hours of a clear sky and a bright sunshine their color is changed to a beautiful green.” Another writer fortifies this statement with the additional fancy ‘‘ that a forest in which the sun has not shone for twenty days, the leaves were expanded but were almost white. One forenoon the sun began to shine in full brightness: the color of the forest changed so fast that we could perceive its progress.” An analysis of etiolated specimens of Prsum satzvum, Hordeum vulgare and Avena sativum by Vogel” in 1856 led him to the gen- *3Gardner. London, Edinburgh and Dublin Philosophical Magazine. 1844. *% Draper. Chemistry of plants. 1844. New York. *Dutrochet. Rapport sur un mémoire de M. Payer intitulé: Mémoire sur la tend- ance des racines a fuir la lumiére. Ann. Sc. Nat. III. 2: 96. 1844. *° Carpenter, M.B. Vegetable Physiology, and Systematic Botany. P.198. 1848. 77 Vogel, A. Beitrage zur Kenntniss der Verhiltnisses zwischen Licht und Vegeta- tion. Flora, 39: 385. 1856.’ MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. a eralization that etiolated plants contained 2 per cent. more water thin normal specimens. The ash constituent showed an increase of 4 per cent. and the proportion of carbon decreased. Measurements of root systems suggested a more marked development of these organs than those of plants in light. Guillemin”™® states that etiolated plants developed green’color more rapidly in blue, yellow, green, and orange or red, than in direct sun- light, and that the action of yellow light was equal to that of diffuse daylight. The chemical nature of chlorophyl and the manner of its forma- -tion engaged the attention of a number of authors. Gris” made a series of investigations upon the behavior of chloroplasts and the for- mation of chlorophy] in 1857 in which he etiolated plants of Semper- vivum tectorum, S. Haworthit, Sedum dendrotdeum, Aloe obligua, Vicia Faba, Oxalis, bean and erythrine. Chloroplasts appeared to diminish in size during the process of blanching. Some data were given by him concerning the form and character of the protoplasm of etiolated organs to which reference will be made in a later part of this paper. Sachs” began the study of etiolation phenomena and the publica- tion of his results in 1859, and interest in this subject was most ac- tive in the decade following, numbers of investigations being carried on in the Wiirzburger laboratory by Sachs and his students, and by other workers in Germany, France and England. Sachs’* earliest observations were concerned with the relations of light to chlorophyll principally, as well as the origin of starch, but as may be seen a widening attention was given the subject, and growth, development, and stature of etiolated plants were dealt with in great detail. Sachs saw the construction of chlorophyll in cells in which %Guillemin, C. M. Production de la chlorophylle, et direction des tiges sous Vin. fluence des rayons ultra-violets, calorifiques. et lumineux du spectre solaire. Ann. Sc. Nat. IV. 7: 154. 1857. 22Gris, A. De étiolement. Recherches microscopiques sur la chlorophylle. Ann. Mateoci.1V.7: 207. 1857. 30Sachs. Handbuch d. physiol. Bot. 1865. See Lotos, Jan. 1859. 3tSachs. Ueber den Einfluss des Lichtes auf die Bildung des Amylums in den Chlorophyllkérnern. Bot. Zeitung, 20: 365. 1862. Sachs. Uebersicht der Ergebnisse der neueren Untersuchungen ueber das Chlo- rophyll. Flora, 45: 129. 1862. Sachs. Ueber den Eintluss des Tageslichtes auf Neubildung und Entfaltung verschiedener Pflanzenorgane. Bot. Zeitung, 21: Beil. 31. 1863. 8 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. he thought the chloroplasts had not yet assumed form, and the degeneration of these bodies was seen in etiolated examples of Cucurbita, Zea Mars, and Helianthus annuus. He noted that ger- minating bulbs of Ald’wm Cepa produced leaves of the usual length in darkness, but these organs were more slender and thinner, not showing the central lysigenetic cavity. The protoplasm in this plant as well as in Beta vulgaris, Apium graveolens, Zea, Helianthus, Phaseolus, and Cucurbita grown in darkness appeared highly granular. Seedlings grown in darkness appeared to continue existence until all of the reserve material in the seed was exhausted, and then died unless brought into light of an intensity sufficient to cause the forma- tion of food at such rates as to show the presence of starch in the leaves. Starch was always found in the guard cells of the stomata of such presumably starved specimens. It is well established by the results of more recent workers that the seedling rarely if ever totally exhausts the available supply of food in the seed. Normal stomata were produced by etiolated plants of Beta vul- garis, Dahlia variabilis and Phaseolus multiflorus, except that the chloroplasts were in the etiolated condition. Inflorescences of /Vzcotcana thrust into a dark chamber un- folded the corollas normally and produced seeds of a size above the normal, which germinated in the usual manner. Adventitious roots were formed in great abundance on portions of stems of Phaseolus, Vicia Kaba, Helianthus tuberosus, Cactus speciosus and Crcuta virosa in darkness much more abundantly than in light ; many of these plants not forming such organs in light. A group of monocotyledonous species included in Zea, Tritecum, Crocus, Iris, Hyacinthus, Tulipa and Adium formed etiolated leaves of a length greatly in excess of the normal, but of inferior width in darkness. Flyacinthus leaves attained an exaggerated length but the laminae were rolled up in cylindrical form, an observation which was confirmed by my own observations. Leaves of Tragopogon porrifolius were of the customary length in darkness, while those of Phaseolus, Tropaeo- lum, Humulus, Begonia and Solanum attained only a fraction of their normal size in darkness, and in some species retained the position assumed in the bud. Etiolated specimens of Bryonza bore tendrils of average size which were normally sensitive and were able to grasp supports; an observation previously made by von Mohl. Leaves of Se MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 9 Bela vulgaris attained greater length in light than in darkness. Cotyledons of I@rabdilis Jalapa, Brassica, Polygonum, Fagopyrum, Cucurbita and Hlelianthus did not attain normal size. Fronds of Pter7s chrysocarpa grown in darkness were green in color in accordance with results previously attained by DeCandolle. Hypocotyls of Fagopy- rum, Cucurbita Pepo, Brassica, Napus, Phaseolus multiforus and Tropacolum majus were excessively elongated in darkness, reaching twenty times the normal length. Scapes of Hyacinthus oriental/s, Tulipa Gesneriana and Jris pumila were greatly elongated in dark- ness, while the scape of Crocus verna remained of average length but showed an excessive growth of the perianth tube. Internodes of Dvéoscorea Batatas and Bryonia diorca did not increase beyond the average normal length, although such increase was observed in Phaseolus multiforus. The short thick stems of beets and cacti did not elongate beyond the normal in darkness, and the diameter of etiolated stems of Phaseolus multiforus, Vicia Faba, Dioscorea Batatas and Tropacolum showed but little variation from the ordinary measurements. The hypocotyl of Cucurbita Pepo, which is cylindrical in cross section in normal plants, was more or less flattened in etiolated examples. Normal torsions were found in etiolated stems of Bryonda and other climbers, and are also exhibited by many species in which such properties are not usually present, such as the hypocotyl of Miraditis Jalapa, Brassica Napus, B. oleracea, Chetranthus Chetrit, Linum grandiforum, Helianthus annuus, scapes of Hyacinthus ortental’s, internodes of Vzcza Kaba, cotyledons of Scorzonera Hispanica, and leaves of Hyacinthus orientalis. A great diversity of reaction was exhibited by flowers. According to Sachs’ results flowers of Tu/pa, flyacinthus, [ris and Crocus reach an advanced stage of develop- ment in darkness, although the facts adduced are not confirmed by my own observations. Flowers of Brassica, Tropacolum, Papaver, Cucurbita and others might not carry on their entire development in darkness, but if the buds were allowed to reach the stage immediately preliminary to opening or thereabouts, in light, flowers of reduced size, but normal structure, were produced. Sachs’ investigations upon this subject were continued for about fifteen years, and received some attention during the remainder of his lifetime. In addition to the papers cited other brief notes were published and the entire subject was discussed in his collected works. IO MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. Among the additional facts obtained it is to be noted that Veronzca speciosa developed normal flowers and fruits and also Ipomoea pur- purea. A fruit of Cucurbita Pepo weighing 472.5 grams was pro- duced in darkness. Seeds of this fruit, as well as those of Adllzwm porrium and Papaver somniferum grown in darkness germinated in the usual manner. I am constrained to call attention to the fact that these results have not been confirmed by Amelung, who carried out a similar series of tests in 1894. The general relations of light to form and growth were considered in later papers by Sachs, and with- out further discussion of his lengthly dissertations the chief conclu- sions may be briefly stated as follows : Light is not necessary for cell-division of non-green organs, but is indispensable for organs containing chlorophyl. Exaggerated elongation of internodes is accomplished by increased extension of the cells, not by multiplication of cells. The chief purpose of stems is to carry buds aloft to sunlight, and most stems form greatly elongated internodes when etiolated ; to this may be noted the exceptions which fall into two groups. One in- cludes plants with long slender internodes supposed to be normally etiolated, and the other with compressed internodes which exhibit no capacity for elongation.” The development or non-development of flowers in darkness was held to be dependent upon the presence of the special nutritive sub- stances necessary for their growth. Plants with adequate supplies of special reserve material might form normal flowers in darkness, but plants devoid of such reserve material might perfect flowers only when a branch or leafy stem was exposed to the light and could furnish the necessary constructive material. The term Photolonus was applied to the condition of the plant when receiving illumination of a certain intensity sufficient to induce a labile condition of the protoplasm. Under such conditions the *Sachs. Ueber den Einfluss der Lufttemperatur und des Tageslichts auf die stiindlichen und taglichen Aenderungen des Lingenwachstums (Streckung) der Inter- nodien. Arb. a. d. Bot. Inst. i. Wiirzburg, 1: 99. 1872. Sachs. Vorlesungen ueber Pflanzenphysiologie. 1865. Sachs. Wirkung farbigen Lichts auf Pflanzen. Bot. Zeitung, 22: 353, 361; 369. 1864. Sachs. Ueber die Wirkung der ultravioletten Strahlen auf die Bliithenbildung. Arb. a. d. Bot. Inst. i. Wiirzburg, 3: 372. 1887. Sachs. Gesammelte Abhandlungen ueber Pflanzenphysiologie, 1: 229, 261. 1892. MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. Il plant might accomplish normal growth, food formation and devel- opment. Darkness-rigor was used to denote the stable and non- 1-motile condition of protoplasm after continued deprivation of illumination, under which circumstances all periodic movements and other activi- ties were said to cease. Variations in intensities of illumination were supposed to induce the assumption of day and night positions of leaves, and other organs in a phototonic condition, by the paratonic action of the rays. Leaves and internodes which have grown under normal alternations of day and night grow more slowly in temporary illumination than in darkness, due to the retarding action of light. Etiolation is a pathological condition, and the diminished stature of leaves is due to defective nutrition, and not to lack of illumination alone. . Only chlorophyl-bearing organs might be etiolated ; floral organs, customarily free from chlorophyl, fruits and seeds, may develop in a fairly normal manner in darkness. It is notable that the investigations of Sachs and the workers in his laboratory resulted in the record of an enormous number of facts . concerning growth and the relation of light to plants, and that these researches led the way to nearly all of the modern work upon the subject, yet scarcely a single one of his conclusions concerning etiola- tion, and the influence of light upon growth are tenable at the present time except in modified form. Some of his imperfect interpretations must have been due to a failure to comprehend the aon of the reactions of fungi to light and darkness. G. Kraus’* conclusions published in 1869 ascribed the undevel- oped stature of etiolated leaves to a lack of nutrition, upon the sup- position that leaves were dependent upon the products of their own chlorophyl apparatus for food: The excessive elongation of etiolated stems was supposed by Kraus to be due in part to a slight multipli- cation of the cells, and to an exaggerated elongation of these ele- ments. Stress was laid upon the predominating influence of turgid parenchyma cells as a positive factor in such stretching. The walls of the fundamental system were seen to remain unthickened for a month or more, in etiolated stems. Torsions were found in all 33Kraus, G. Ueber die Ursachen der Forminderungen etiolirender Pflanzen. Jahrb. Wiss. Bot. 7: 209. 1869. I2 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. hypocotyls, but were not analogous to the torsions of climbing stems, being produced directly by the inclined position and prosenchyma- tous form of the epidermal cells. Later some important investiga- tions were made by Kraus upon the water content of plants in light and darkness in which he found that etiolated plants showed a greater percentage of water in their composition. The exclusion of light from a plant was followed by a swelling due to an increase of the amount of water present, and the actual size of the plant showed fluctuations during the day, which were more or less irregular. The acidity of the sap of plants were observed to increase in dark- ness for the most part, and in many instances the acidity of etiolated plants was greater than that of normal specimens.” Kraus completed some experiments upon the influence of partial spectra upon plants in 1876, from which he reported that excessive elongation of aérial roots and stems in M/mosa and Urtica dioica occurs in red and yellow light as in darkness. J/mosa did not go into a condition of darkness rigor in yellow light and soon recovered from darkness rigor when placed in yellow light. This plant was found to go into darkness rigor in green light in confirmation of earlier results by Bert.” Batalin*®* wrote two contributions upon this subject in 1869 and 1871. His earlier work was directed toward a study of the influence of light upon the separate tissues, and may be best stated in an adap- tation of his own summary. Light exercises no influence upon the division of epidermal cells, as illustrated by observations on Lepidium sattvum. Diffuse light facilitates division of the cortical parenchyma (Leprdium sativum), and direct sunlight exercises the same effect on these cells as darkness. Light acts favorably on the formation of woody tissue (Cannabis sativa, Zea Mazs), and the formation of secondary bundles is facilitated by light (7riticum vulgare, Zea Mais). Collenchymatous thickening is carried on only to a limited extent in darkness (Solanum tuberosum), while the thickening of the walls of bast and wood cells is not affected by light. Not all of these results are confirmed by later investigations. * Kraus. Ueber die Wasservertheilung inder Pflanze. I. Halle. 1879. III. Die tagliche Schwellungsperiode der Pflanze. 1881. IV. Die Aciditit des Zellsaftes 1884. 35Kraus, G. Versuche mit Pflanzen im farbigen Licht. Abdruck a. d. Sitzungs- ber. d. Naturf. Ges. z. Halle. 1876. * Batalin, A. Ueber die Wirkung des Lichtes auf das Gewebe einiger mono- und dicotyledoner Pflanzen. Bull. d. 1. Acad. Imp. d. St. Petersbourg, 7: 269. 1869. MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 13 Later Batalin” combated the self-nutrition of leaves as formulated by Kraus, and held that chlorophy] plays no direct part in the develop- ment of the leaf, this organ being able to carry on growth as long as it was furnished food. He upheld his former contention that the small size of etiolated leaves is due to their inability to carry on cell division in darkness. He also called attention to the mistaken statement of Weiss* that etiolated leaves have the same number of stomata as normal leaves. Famintzin*® carried out some experiments in an effort to analyze the growth of algae in light and darkness, and found that cell- division ensued almost wholly in light. His claim that this relation of light to division is not due to nutritive conditions, rests chiefly upon a series of tests in which filaments of Spzvogyra were exposed to light until the cells were loaded with starch, then some were con- tinued in light and others were placed in darkness. In such instances the greatest multiplication was shown by the illuminated filaments. Karsten’s * tests showed a greater proportion of cellulose in etiolated specimens than in the normal, or an actual amount about equal to the normal. Prantl* investigated the relation of light to growth in Sach’s laboratory and by measurement of the number and size of cells in etiolated, and embryonic normal leaves, concluded that cell division does ensue in etiolated organs of this character. In addition to a re-statement of some of Sachs’ conclusions regarding influence of light upon growth, he also repeats the assertion of Sachs that etiolated leaves are in a pathological condition, due to the lack of the specific substances necessary for their proper nutrition. 37 Batalin, A. Ueber die Wirkung des Lichtes auf die Entwickelung der Blatter. Bot. Zeitung, 29: 669. 1871. 38 Weiss, A. Untersuchungen ueber die Zahlen und Grossenverhialtnisse der Spal- toffnungen. Jahrb. f. Wiss. Bot. 4: 125. 1865-1866. 39Famintzin, A. Die Wirkung des Lichtes auf Algen und einige andere ihnen nahe verwandte Organismen. Jahrb. f. wiss. Bot. 6: 1. 1867. Famintzin, A. Die Wirkung des Lichts auf das Wachsen keimenden Kresse. Mem. Acad. St. Petersb. 8: p. 13. No. 15. 1865. 40Karsten, H. Vergleichenden Untersuchungen von in Lichte und Dunkeln gezo- genen Pflanzen. Der Chem. Ackersman. No. 3. 1870. Karsten, H. Die Einwirkung des Lichtes auf das ;Wachstum der Pflanzen beo- bachtet bei Keimung der Schminkbohnen. Inaug. Diss. Jena. 1870. 41 Prantl, K. Ueber den Einfluss des Lichtes auf das Wachstum der Blatter. Arb. a. d. Bot. Inst. Wiirzburg, 1: 371. 1873. 14 MEMOIRS OF.THE NEW YORK BOTANICAL GARDEN. As early as 1873 Godlewsky ” maintained that the form of etiolated leaves was not due to lack of nutrition, and as will be shown later, he consistently progressed in the development of a theory of etiola- tion as an adaptation. Detmer “ investigated the influence of varying intensities of light upon the elongation, turgidity and composition of etiolated shoots. The amount of elongation shown by stems was found to increase with the diminishing intensity of illumination, and was ascribed to the ‘‘ great turgor extension of the cells,” while the expansion of the leaves decreased under the same circumstances. The percentage of dry matter in shoots was lessened as the intensity of the illumina- tion diminished. In a later research it was observed that etiolated seedlings of Cucurbita held the cotyledons in an erect position with the inner surfaces appressed. An exposure to light would bring these organs down to the normal horizontal position. As a result of this and similar observations Detmer concluded that light directly affected the relative rapidity of growth of the sides of a dorsiventral organ, and he used the terms photo-epinasty and photo-hyponasty to desig- nate such relation.“ Lasareff * believed he had established a correlation between the length of the stem and the extent of the root-system in etiolated plants in confirmation of some results obtained by Famintzin. The total length of the roots of a number of common forms decreased as the length of the stem increased, in etiolated series, and secondary roots were shorter and fewer. Strehl “ made a series of measurements of the roots and hypo- cotyls of Lupinus albus, by which it appeared that those grown in darkness attained much greater lengths than those under ordinary *” Godlewsky, E. Abhangigkeit der Stirkebildung in den Chlorophyllkérnern von den Kohlensauregehalt der Luft. Flora, 56: 378. 1873. *Detmer, W. Ueber den Einfluss verschiedener Lichtintensititen auf die Entwick- elung einiger Pflanzen. Landw. Versuchss. 16: 205. 1873. See also Detmer, Prac- tical Plant Physiology. Pp. 404-411. 1898, and Detmer, Vergleichende Physiologie d. Keimungsprocesses d. Samen. 1880. “Detmer, W. Ueber Photoepinastie der Blatter. Bot. Zeitung. 40: 787. 1882. ’ Lasareff, N. Ueber die Wirkung des Etiolirens auf die Form der Stengel. Beil. z. Protocoll d. 45th Sitzung. d. Naturf. Ges. a. d. Uniy. z. Kasan. Abstract in Bot. Jahresber. 2: 775. 1874. *Strehl, R. Untersuchungen iiber das Liangenwachstum der Wurzel und des hypokotylen Glied. 1874. MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 15 conditions. These experiments did not clearly demonstrate the re- tarding influences of light, however. This is also true of von Wol- koff’s measurements as described by Sachs.” Koch’s * examinations of etiolated stems of cereals revealed the imperfect development of certain tissues of mechanical value which resulted in the ‘‘ laying ” of plants when grown too closely crowded. Decrease of illumination was found to cause an exaggerated extension of stems due to the greater elongation of their components, and was accompanied by an attainment of a diameter below the normal. Such changes ensued only in organs treated while in the earlier stages of growth and as these alterations rested upon the action of existing cells rather than upon the formation of new elements, the elongation was greatest in the basal portions of internodes. Less thickening ensued in the walls of such elongated elements but lignification pro- ceeded in the customary manner. In some investigations of the relation of light to the construction and disintegration of chlorophyl, Wiesner*® found that this substance might originate in an etiolated specimen in an illumination too faint to be discerned by the eye, a fact of great importance in imperfect etiolation. Disintegration ensued only when light of sufficient in- tensity to cause food formation was allowed to act upon the plant. The formation of chlorophy] in etiolated plants ensued most quickly in rays passing through a solution of cupric ammonia. The self-nutrition theory of G. Kraus and others was affirmed by C. Kraus in some publications in 1875, and he also concurred in the theory of Sachs that light retards growth by its direct action. Later C. Kraus attempted a refutation of the principal results of Godlewsky’s earlier researches. Walz” performed a series of tests of wide inclusiveness in 1875 in which it was confirmed that spores of ferns and odspores of 47Sachs. Text Book of Botany, 2d Ed., p. 835. Koch. Abnorme Aenderungen wachsender Pflanzenorgane durch Beschattung. Berlin 1872. # Wiesner, J. Vorliufige Mittheilung iiber den Einfluss des Lichtes auf Entste- hung und Zerstérung des Chlorophylls. Bot. Zeitung, 32: 116. 1874. 50Kraus, C. Pflanzenphysiologischen Untersuchungen. VI. Wachstum und Chlorophyllbildung. Flora, 58: 346. 1875. Kraus, C. Ursachen der Forminderung etiolirter Pflanzen. Bot. Zeitung, 37: B82. (18709. 51 Walz, J. W. Ueber die Wirkung des Lichtes auf einige Processe des Pflanzen- lebens. Schrift. d. k. Neuruss. Univ. i. Odessa,17: —. 1875. Abstract in Bot. Jahr- esber. 3: 786. 1875. 16 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. Vaucherta sessilis germinating in darkness produced chlorophyl. Amaryllis formosissima produced normal flowers in darkness but with altered colorations. The length and thickness of roots of etiolated plants was less than those grown inlight. The total length of the roots of an etiolated Phaseolus vulgare was '70o mm. ‘Total length of illumined roots with etiolated shoot 1,254 mm. Total length of root system with entire plant illumined 6,276 mm. Total length of root system with illumined shoot and darkened roots, 3,256mm. These measurements were made on plants grown in water cultures. The roots of an etiolated specimen of Helzanthus annuus measured 974 mm., and in an example with etiolated shoot and illumined roots the latter gave a total measurement of 1,252 mm. Mer” found a correlation existed among the members of the shoot by reason of which the excessive elongation of one was ac- companied by the lessened growth of others. He concluded that plants with a basipetal mode of development were unable to extend these organs to their normal position. Internodes and petioles be- come longer in darkness by reason of lessened tissue tensions. ‘The shortness and non-development of branches and other organs was attributed to lack of nutrition. Rzentkowsky ” reported similar correlations expressed in terms of rate of growth. He also found that etiolated plants take up less mineral matter than normal ones, a fact probably resultant from the lessened transpiration. Borodin™ estimated the respiration of branches of Crataegus monogyna and Spiraea opulifolra in darkness and found that the quantity of carbon dioxide exhaled was much increased during the period immediately following deprivation of light. Twelve hours later the rate of liberation of this gas had decreased to half the normal, and 24 hours later to one third. The normal rate was quickly resumed when illumination was restored, presumably due to the formation of material available in respiration, according to the author. “Mer, E. Recherches sur les anomalies de dimensions des entre-noeuds et de feuilles étiolées. Bull. Bot. Soc. d. France, 22: 190. 1875. 3 Rzentkowsky, T. Untersuchung iiber die Entwickelung des etiolirten Phaseolus multifiorus. Mitth.a.d.Univ.z. Warschau. Abstract in Bot. Jahresber. 4: 745. 1876. ** Borodin, J. Physiologischer Untersuchung iiber die Athmung der bebliitterten Sprosse. Arb. d. St. Petersb. Ges. d. Naturf. 7: 1-114. 1876. Abstract in Bot. Jahres- ber. 4: 919. 1876. | : | MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 17 A continuation of the etiolation of inflorescences after Sachs’ method was undertaken by Askenasy,” who found that flowers of flyacinthus ortentalis, Scilla campanulata, Pulmonaria officin- alis, Orchis ustulata, Silene pedula, Antirrhinum majus, Digt- talis purpurea and Prunella grandiflora did not exhibit the nor- mal color scheme. Not only were green floral envelopes blanched, but variations in the depth of other pigmentated areas were observ- able. Heckel® believed he had demonstrated that certain organs, which were normally irritable to contact, went into a condition of rigor in darkness, an observation that could not be confirmed by Preier. Baranetzky ” investigated the relation of the rate of growth to darkness and illumination with the result that he concluded that the daily periodicity in growth was not due directly to the alternating periods of illumination and darkness, but was an after effect. Thus plants exhibiting daily periodicity in the rate of growth did so on several successive days when placed in darkness, and after the rhythm was lost in darkness it was again taken up after exposure to illumination for twelve hours. Brefeld * observed that the growth and development of fungi is more or less dependent upon light, and that sporophores of many fungi exhibited excessive elongation in darkness. ‘The sporophore of Pilobolus microsporus attained a length of half an inch in light and of 8 to 10 inches in darkness. Schulzer von Muggenburg reported a number of collected ob- servations concerning the relations of fungi to light which are in harmony with Brefeld’s results.” A large number of notices showing that different species of fungi exhibit the most diverse reactions to the presence and absence of light were published between 1875 and 55 Askenasy, E. Ueber den Einfluss des Lichtes auf die Farbe der Bliithen. Bot. Zeitung, 34: 1,27. 1876. 56 Heckel, E. Du mouvement végétal. Paris. 1875. Review by Pfetfer in Bot. Zeitung, 34: 9. 1876. 51 Baranetzky, J. Die selbststindige taigliche Periodicitat im Langenwachstum der Internodien. Bot. Zeitung, 35: 639. 1877. 58 Brefeld. Ueber die Bedeutung des Lichtes fiir die Entwickelung der Pilze. Bot. Zeitung, 35: 386. 1877. Also, Sitzungsber. d. Ges. Naturf. z. Berlin. April. 1877. 59Schulzer von Muggenburg. Des allelebenden Lichtes Einfluss auf die Pilzwelt. Flora, 61: 119. 1878. 18 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 1890, to which no reference will be made here; a full discussion is given in the monographs of Elfving and Grantz.™ Rauwenhoff® made extensive investigations of the relations of light to form, and development of tissues, a preliminary notice of which was published in 1876 and the full account in 1878. He con- cluded that not only the pith but the entire fundamental tissue par- ticipated as active factors in the excessive lengthening of stems. He regarded the theories of Kraus and also of Batalin regarding the small size of etiolated cotyledons as untenable. The lack of thicken- ing of walls, and the non-development of the wood and sheath in the fibrovascular bundles was noted. The theories of the correlation existing between the root and shoot by which the former showed a decreased development in etiolated specimens were not confirmed. Rauwenhoff concluded that leaves exhibiting marked dorsiventrality were most likely to remain small in etiolation. The anomalous structures of etiolated plants were ascribed to the action of negative geotropism, unhindered by heliotropism. Lastly Rauwenhoff re- garded etiolation as a pathological phenomenon. Stebler™ attempted a refutation of the theory of Sachs as the universal prevalence of a daily periodicity of growth. Stebler accepted the conclusion that light may retard growth, but found that the greatest increase in monocotyledonous leaves occurred during the most intense illumination, and that this growth is intimately con- nected with food-formation. Such daily maxima also occurred at a corresponding part of the middle of the day in etiolated specimens. Dicotyledonous leaves exhibited the most rapid growth in the middle of the forenoon, which continued until the favorable influence of rapid food-formation was counterbalanced by the retarding influence of light. The decreased and decreasing rate continued until the following morning when assimilation was again resumed. The difference in the behavior of the two forms of leaves was due to the location of the growing region, which is basal in the linear mono- cotyledonous type and is shielded from the direct action of the rays. *Elfving, F. Studien ueber die Einwirkung des Lichts auf die Pilze. Helsing- fors. 1890. Grantz, F. Ueber den Einfluss des Lichtes auf die Entwickelung einiger Pilze. Leipzig. 1898. *' Rauwenhoff, N. W. P. Sur les causes des formes anormales des plantes. Ann. Sc. Nat. VI. 5: 267. 1878. ®? Stebler, F.G. Untersuchungen iiber das Blattwachstum. Jahrb. f. Wiss. Bot. Ir: 47- 1878, MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. Ig Another attempt to establish a correlation among the members of the shoot and root systems was made by C. Kraus®™ in 1878. He believed he had demonstrated that the smallness of etiolated leaves was caused directly by the excessive elongation of the internodes and the increased length of the shoot was accompanied by a similar decrease in the root-sysem. These measurements were thought to be correspondent to the degree of turgidity exhibited by the organs concerned. Vines™ made two series of experiments to ascertain the direct relation of light to growth in 1878, at the laboratories in Wiirzburg. Partial spectra and atmospheres lacking carbon dioxide were used in some of the tests. From direct measurements of the rate of elon- gation of sporophores of Phycomyces in darkness and light, and in various portions of the spectrum he concluded that light retards growth by the direct action of the blue-violet rays, and this effect was supposed to be due to a decrease in the mobility of the micellae of the peripheral layers of protoplasm. These conclusions, as well as the more important generalizations made by Sachs, are given by Vines in his text-books of plant physiology and botany and do not need further description here. Godlewsky ® took up the subject for the second time in 1879 and his principal results may be stated as follows: The organic material in an etiolated seedling, and in one grown in atmosphere lacking carbon dioxide is not greater than the amount present in the seed, and is approximately equal in the two instances. The altered form of the stem and cotyledon is not due to altered assimilation. The total amount of dry material in cotyledons of etiolated seed- lings of Raphanus is less than in green ones. Roots of etiolated plants may be slightly less developed than in the normal, yet no regular correlation appears between the root and shoot in this con- nection. 63 Kraus, C. Ueber einige Beziehungen des Lichtes zur Form und Stoffbildung der Pflanzen. Flora, 61: 145. 1578. 64 Vines, S. H. The Influence of Light upon the Growth of Leaves. Arb. a. d. Bot. Inst. i. Wiirzburg, 2: 114. 1878. Vines, S. H. The Influence of Light upon the Growth of Unicellular Organs. Arb. a. d. Bot. Inst. i. Wiirzburg, 2: 133. 1878. Vines, S. H. Physiology of Plants. 1886, and Student’s Text-book of Botany. 1896. 85 Godlewsky, E. Zur Kenntniss der Ursachen der Forminderung etiolirter Pflan- zen. Bot. Zeitung, 37: 81, 97, 113, 137- 1879. 20 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN, According to Wiesner’s™ investigations etiolated seedlings are capable of much more delicate phototropic reactions than others grown in diffuse light. He also believed to have confirmed the con- clusion that light retards growth, finding that such effect was exer- cised even by intensities insufficient to act as phototropic stimuli. The retarding effect was attributed to the entire spectrum, and was quite as great in intense yellow as in blue light. The retarding in- fluence of light was ascribed to the action of the rays not only on the peripheral layers of protoplasm, but also on the wal., as well as upon turgidity. A decade later Godlewsky™ reviewed the entire subject and, after a masterly discussion of the established facts of etiolation, concluded that the theories of self-nutrition and that etiolation was a pathological phenomenon, were inadequate. He proposed instead that such reac- tions were purely adaptive in their nature and are designed to bring the reproductive and food forming organs up inte light as rapidly as possible, the food and energy of the plant being directed to the development of the members which would accomplish this purpose. The same theory had been proposed in a general form by Boehm” three years previously. In some later investigations by Godlewsky plants kept in dark- ness until 11 A. M. were found to exhibit a minimum rate at g A. M., and after illumination at 11 A. M. the rate was below the normal. The elongating zones were found to be longer in etiolated than in normal green plants, but the turgidity was no greater. Godlewsky affirms that the ductility of etiolated and normal stems is about the same. Maximum ductility in any given cell is maintained longer in etiolated plants however. The illumination of an etiolated plant is followed by a decrease of ductility and elasticity of the older cells of the growing zone. Light was supposed to check the superficial expansion of growing cells, and retard elongation. 8 Wiesner, J. Die heliotropischen Erscheinungen im Pflanzenreiche. II. Th. 7. 1880. Godlewsky, E. Ueber die biologische Bedeutung der Etiolirungsercheinungen. Biol. Centralblatt, 9: 481. 1889. Godlewsky, E. Ueber die Beeinflussung des Wachstums der Pflanzen durch aeus- sere Factoren. Anzeig. d. Akad. d. Wiss. z. Krakau. Résumés, p. 206. 1890. Godlewsky, E. Die Art und Weise der Wachstumsretardirenden Lichtwirkung ue die Wachstumstheorien. Anzeig.d. Akad. d. Wiss. z. Krakau. Résumés, p. 166. 1890. Boehm. Die Nahrstoffe der Pflanze. 1886. MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 21 An interesting example of excessive elongation due to etiolation is given by Krabbe” who records that the apothecial stalks of Baeo- myces attain a length much beyond the normal when deprived of illumination. Vochting ” found that light exerted a strong selective influence in the development of shoots; only the buds favorably acted upon by light showed activity in the formation of branches. Later a reverse in- stance of this action was seen in the potato in which tubers were formed only on organs deprived of illumination. V6chting has car- ried out a large number of researches which bear directly and indi- rectly upon this subject. He found that leaves of etiolated plants brought into light in an atmosphere lacking carbon dioxide did not form chlorophyl, and hence concluded that the growth of these organs is intimately connected with their food-forming operations. Later he also found that the formation of flowers is closely connected with the activity of the leaves, in addition to which light exerts a direct morphogenic effect upon these structures. Diverse reactions were recorded in which some flowers were seen not to open in dark- ness or diffuse light, while others opened but did not reach normal stature. Light also exerted various effects upon the essential parts of the flower. Asa result of a series of etiolations of cacti it was found that the form of these plants is largely dependent upon illumi- nation, and that deprivation of light acts as a stimulus which calls out renewed growth. Noll” relates that etiolated twining plants were capable of grasp- ing supports in the usual manner, such action being ascribed to nega- tive geotropism and circumnutation, an experience that has been 6 Krabbe, G. Entwickelung, Sprossung und Theilung einiger Flechten Apothe- cien. Bot. Zeitung, 40: 93. 1582. 7 Véchting, H. Organbildung im Pflanzenreich, 2: 66. 1884. Véchting, H. Ueber der Knollenbildung. Bibl. Botan. 1: Hft. 4. 1887. Vichting, H. Ueber die Abhingigkeit des Laubblattes von seiner Assimila- tionsthitigkeit. Bot. Zeitung. 49: 113. 1891. Véchting, H. Ueber den Einfluss des Lichtes auf die Gestaltung und Anlage der Bliithen. Jahrb. f. Wiss. Bot. 25: 149. 1893. , Voichting, H. Ueber die Bedeutung des Lichtes fiir die Gestaltung blattférmiger Cacteen. Zur Theorie der Blattsteilungen. Jahrb. f. wiss. Bot. 26: 438. 1894. Voéchting, H. Zur Physiologie der Knollenge wichse. Jahrb. f. Wiss. Bot. 34: Te 1900... See also, Istvanffi, G. Influence of Light upon the Development of Flowers. 18go. 71Noll, F. Ueber rotirenden Nutation an etiolirenden Keimpflanzen. Bot. Zeitung. 43: 664. 1885. 22 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. duplicated by no other worker on this subject so far as the records are available. | Klein ” made a series of experiments to determine the factors to which the nocturnal spore formation of Botrytis cinerea might be ascribed, and concluded that the blue violet rays exerted such direct action as to prevent their production during the daytime. The red- yellow rays facilitated spore formation, and the absence of light allowed it to proceed normally. The etiolation of a number of such extremely hairy forms as Urticula pilulifera, Cynoglossum officinale, Anchusa officinalis, Cu- curbita Melopepo, Echallium elaterium, Soja hispida, Salvia argen- tea, Stachys lanata, Mirabilis Jalapa, Abutilon Avicennae, Gloxinia hybrida, Solanum tuberosum, Dahlia variabilis, Mentha piperita and M. crispa, by Schober™ resulted only in the diminution of the size of the trichomes, or excessive growth correspondent to that of the organs on which they are borne. The stellate hairs of Adutelon were not borne by etiolated specimens. The above results must be.ac- cepted with some caution, however, since etiolations were affected by covering shoots with flower pots and could hardly have been absolute. As a result of some researches upon the structure of. leaves Dufour ™ concluded that these organs reached a greater extension in sunlight than in shade, that the epidermal cells were larger, the number of stomata greater and that a continued formation of these organs ensued occurred through a large part of the period of develop- ment of the leaf. Stahl” had previously published the results of his extensive researches upon the general relations of the form and size of leaves to light exposure and other factors. Uhlitzsch” showed that the extension of petioles is greater in etiolated than normal leaves, but that growth may be variously affected by light in different species. The length of the period of growth is also dependent upon the intensity of the illumination. Klein, L. Ueber die Ursachen der ausschliesslich nichtlichen Sporenbildung von Botrytis cinerea. Bot. Zeitung, 43: 6. 1885. Schober, A. Ueber das Wachstum der Pflanzenhaare an etiolirten Blatt- und Achsenorganen. Zeitschr. f. Naturw. IV. 58:4: 556. Abstract in Bot. Centralb. 28: 39. 1886. : ™ Dufour, L.. Influence de la lumiére sur Ja structure des feuilles. Bull. Bot. Soc. d. France, II. 8: g2. 1886. % Stahl, E. Ueber die Einfluss des Standortes auf die Ausbildung der*Laubblitter. 1883. Uhlitzsch, P.G. Untersuchungen iiber das Wachstum der Blattstiele. 1887. MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 23 Vines” examined Detmer’s conclusions as to photo-epinasty and photo-hyponasty and demonstrated that such movements are sponta- neous, and not induced, though occurring under certain intensities of illumination. It was asserted that the above terms might only be properly applied to adaptive movements, such as those in which the leaf assumes a vertical position in consequence of unfavorable in- tensities of illumination. In an attempt to make an orderly classification of the fungi num- erous observations of variations in form have been made as far back as the latter part of the eighteenth century. A few of these observa- tions have been noted on the previous pages, and a thorough biblio- graphical account of this aspect of the subject was published by Elfving,” in 1890. Elfving concluded that light retarded many of the synthetic processes of fungi, though not all of them, and that the ultra-violet as well as the visible rays participated in such action. Similar influence was exerted upon respiration. Diffuse light had effects similar to darkness and diverse reactions were exhibited by various species. Busch made a number of systematic tests of the endurance and development of green plants in darkness in 1889, the principal result of interest in this connection being that fruits not normally containing much chlorophy] might attain normal development in darkness if the leaves were illuminated.” Recent researches tend to show that light has but little influence upon respiration, yet some notable differences are found between the respiration of etiolated and normal plants. Much work upon this phase of the subject has been done by Palladine,® who concluded that the respiratory activity of etiolated shoots is considerably aug- mented by the introduction of sugar into the tissues. The respira- ™Vines,S. H. On Epinasty and Hyponasty. Annals of Botany, 3: 415. 1889. SElfving. Studien iiber die Einwirkung des Lichtes auf die Pilze. 1890. Busch, H. Untersuchungen ueber die Frage ob das Licht zu den immittelbaren Lebensbedingungen der Pflanzen oder einzelner Pflanzenorgane gehort. Inaug. Diss. Bremen. 1889. © Palladine, W. Transpiration als Ursache der Forminderung etiolirter Pflanzen. Ber. d. Deut. Bot. Ges. 8: 364. 1890. Palladine, W. Eiweissgehalt der griinen und etiolirten Blatter. Ber. d. Deut. BGG. Ges. 9: 194. 1891. Palladine, W. Ergriinen und Wachstum der etiolirten Blatter. Ber. d. Deut. BOENGeEs. 94229. 18091. Palladine, W. Recherches sur la respiration des feuilles vertes et des feuilles €tiolées. Rev. Gen. d. Bot. 5: 449. 1893. 24 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. tory quotient of etiolated leaves varies from .72 to .76, in a water cul- ture, it ranges from .63 to .65 and ina culture of sugar about .76. The respiratory activity of both normal and etiolated leaves decreases after confinement in darkness for prolonged periods. Palladine saw in the form of etiolated plants a direct adaptation to the altered transpiratory conditions resulting chiefly from the absence of light, and points out that the anatomy of etiolated stems is much like that of stems grown in chambers with a saturated atmos- phere. A chemical analysis of etiolated plants showed them to be capable of division into two groups. One group, including the stem- less plants contains less proteids than green organs, and the second includes plants with stems, the leaves of which contain more proteid than the normal, while the stems are depleted of this substance. In some experiments upon the formation of green color and growth with separated etiolated leaves, Palladine found that the formation of chlorophy] in etiolated leaves is accomplished only when a supply of sugar is at hand, and that lack of calcium will prevent the devel- opment of leaves of Vicza Kaba. Lamarliere™ concluded that the differences in the structure of leaves in diffuse light from those in direct sunlight corresponded directly to the diminished functions of respiration, food-formation and transpiration in the former instance. C. DeCandolle repeated the experiments of Sachs in testing the influence of the ultra-violet rays, and his results partly confirmed the conclusions of Sachs that these rays are necessary for the construc- tion of specific substances used in the formation and growth of floral organs. The rays in question were excluded from the plants by solutions of quinine and aesculine, and since some flowers were formed on the screened plants a stimulative action of the ultra-violet rays was suggested.” Frank * recognized the futility of attempts to make generaliza- tions on the influence of light upon growth in his text-book in 1892, and concluded that etiolation phenomena are exhibited only by organs, the activity of which is concerned with the sun’s rays. He saw in etiolation an effort to carry organs up to sunlight to the func- *! De Lamarlitre, L.G. Recherches physiologiques sur les feuilles dévellopées a ’ombre et au soleil. Rev. Gen. d. Bot. 4: 481. 1892. * DeCandolle, C. Etude de l’action des rayons ultra-violet sur la formation des fleurs. Arch. des Sc. Phys. et Nat. Genéve, 28: 265-277. 1892. *8 Frank, B. Lehrbuch der Botanik, 1: 389. 1892. MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 25 tions of which the radiations were necessary. His view is practically that of Godlewsky, although he makes no mention of the latter among the references made to other writers. Wiesner made a quantitative examination of the influence of illumination of various intensities in producing etiolative effects and in causing alterations of stature. Leaves and stems were found to respond unequally to such variations.*! Ziegebein™ also found that etiolated shoots of Solanum respired less actively than normal stems. Among other reactions of aquatic plants those shown by Cau- lerpa are strikingly similar to those of the higher plants, according to the observations of Klemm, Noll* and Berthold. No foliar prolifications are produced by specimens grown in darkness and the small number of branches sent out take the form of cylindrical bodies entirely free from chlorophyl. Godlewsky® again attacked the problem of daily variations in the rate of growth and found that daily periodicity might or might not be exhibited. A sudden illumination of a plant which has been kept in darkness for several hours causes a diminution of the rate of growth in a very short time. The decrease continues for 1% to 4% hours then slowly regains the original rate, consequently he held that the daily periodicity was due to the direct influence of light. Frankfurt” made an extensive series of analyses of the composi- tion of seeds and etiolated seedlings of Cannabis sativa and Helian- thus annuus in 1893. Attention was directed chiefly to the estimation of asparagin and glutamin in the first species. Seedlings of Heléan- thus 12 days old were found to be rich in soluble carbohydrates, poor in nitrogenous bases, to contain no starch, some pentosanes, 8*Wiesner, J. Photometrischen Untersuchungen auf Pflanzenphysiologischen Gebiete. Sitzungsber. d. Kaiserl. Akad. d. Wiss. i. Wien. 102: Abth. 1. 1893. % Ziegebein, E. Untersuchungen iiber den Athmung keimende Kartoffelknollen sowie anderer Pflanzen. Jahrb. f. Wiss. Bot. 25: 563. 1893. 8°Klemm, P. Ueber Caulerpa prolifera. Flora, 77: 460. 1893. 8’ Noll, F. Ueber die Einfluss der Lage auf die morphologische Ausbildung einiger Siphoneen. Arb. a. d. Bot. Inst. i. Wurzburg, 3: 466. 1888. Berthold, G. Beitrige zur Morphologie und Physiologie der Meeresalgen. Jahrb. f. Wiss. Bot. 13: 569. 1882. 88Godlewsky, E. Studien iiber das Wachstum der Pflanzen. Abh. d. Krakauer Akad. d. Wiss. Math.-Naturw. Cl. 23: 1-157. Abstract by Rothert. Bot. Centralbl. 55: 34. 1893. Frankfurt, S. Ueber die Zusammensetzung der Samen und etiolirten Keim- Pflanzen. Inaug. Diss. Wilna. 1893. 26 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. and an increased amount of simple nitrogen compounds of organic acids and hemicelluloses. A number of etiolation experiments by Jost*' with buds of trees gave the result that the development of such buds was hindered by darkness in the case of the copper beech. On the other hand firs, rhododendron, horse chestnut and maple developed long thin etiolated shoots, which soon perished, except in the case of the horse chest- nut. In the last-named tree closed winter buds were formed after the etiolated stems had reached a certain length, which perished after another attempt at growth. Only a few buds awoke on an entire plant of copper beech placed in the dark room, affording an example exactly opposite that of the potato. In a second series of tests Jost made a careful examination of the irritable condition of etiolated plants, in which J/zmosa, Phaseolus and other species were used. J/?mosa exhibited its usual capacity for reaction to shock, wounds and other stimuli, and carried on periodic movements in a rhythm fairly correspondent to that in day- light. The atrophied form of etiolated leaves was asserted to be due to lack of nutrition, since rudimentary leaves freed from the compe- tition of concurrent organs arising from the same bud or branch attained normal extension and stature. The death of green leaves in darkness was attributed to the pathological effects of disintegrating chlorophyll.” Amelung” repeated Sachs’ experiment with etiolation of tips of stems of Cucurbita and the flowers produced differed much from the normal. Some of them did not open, and fertilization was accom- plished only by the introduction of pollen grown on plants in the open air. A fruit was formed in darkness as the result of such pol- lination, which showed various divergences from the normal, as well as the seeds which were not capable of germination. Goebel” pointed out that some of the reactions of etiolated plants, or of plants in diffuse light are correlation phenomena, or adaptive processes and are not due to the direct effect of illumination or the 1 Jost, L. Ueber den Einfluss des Lichtes auf das Knospentreiben der Rothbuche. Ber. d. Deut. Bot. Ges. 12: 188. 1894. * Jost, L. Ueber die Abhingigkeit des Laubblattes von seiner Assimilations- thatigkeit. Jahrb. f. Wiss. Bot. 27: 403. 1895. * Amelung. E. Ueber Etiolement. Flora, 78: 204. 1894. “Goebel, K. Ueber die Einwirkung des Lichtes auf die Gestaltung der Kakteen und anderer Pilanze. Flora, 80: 96. 189s. MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 27 lack of it, a supposition parallel to and corroborative of the theory of Godlewsky. Goebel’s general discussion of the subject in his Organ- ography will be considered in a later section of this memoir. Klemm” concluded that light is not necessary for the existence of protoplasm, and a certain maximum intensity acts unfavorably and fatally, producing granulation and rigor, but not vacuolization. Such action is not so marked as with heat radiations, however. The behavior of aquatic plants in darkness offers some interesting data, especially those offered by the seed-plants. Mdébius ® found that Ceratophyllum showed excessive elongation of its internodes, and placed the leaves in a drooping position, as well as the branches. The excessive length of the internodes was correspondent to an ex- cessive elongation of the cells, and no multiplication occurred. The movement by which the tips of the leaves and branches are curved toward the base of the stem is caused by internal forces and is not geotropic. Similar reactions were obtained from Myriophyllum. feanunculus divaricatus did not exhibit marked change. Excessive elongation of internodes was also shown by Elodea. The effect of light upon bacteria and similar organisms has been the object of several important investigations, a history of which is given briefly by H. M. Ward” in the latest paper on the subject. The results obtained by the various workers are by no means in agreement, but it seems fairly well established by Ward that blue, violet and ultra-violet rays exert a fatal effect upon vegetative cells of bacteria and yeasts. These results, however, only have the general significance that the optimum intensity of light for the organ- isms in question is far below that of direct sunlight. The results of continuous illumination, as described by Bonnier, are curiously parallel to those of continuous darkness, according to the observations of specimens exposed to the light of electric arcs. Among other features of interest it was noted that the structure of the leaf was more simplified than in the normal, that the epidermal tissues of the petioles were less highly developed, sclerenchymatous elements being lacking, that the structure of the stems was much % Klemm. Desorganizationserscheinungungen der Zelle. Jahrb. f. wiss. Bot. 28: 627. 1895. % Mobius, M. Ueber einige an Wasserpflanzen beobachtete Reizerscheinungen. Biol. Centralb. 15: 1. 1895. %7 Ward, H. M. The Action of Light on Bacteria. Proc. Roy. Soc. 185: 961. 1895. 28 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. simpler, and that the customary features of the formation of corky tissue and bark were lacking in a marked degree as well as the dif- ferentiation in the parenchymatous tissues. The xylem and pericycle were also less highly developed, in their mechanical features and a special endodermis was formed in Hedleborus niger. Plants exposed to the electric illumination in question and to darkness in alternating periods of 12 hours showed a fairly normal structure.” The author of this memoir published a paper dealing with some cultures of seed-plants in darkness and in atmospheres lacking car- bon dioxide in 1896.” It was proven that material constructed in ac- tive chlorophyl-bearing tissues may be transported to inactive organs in darkness and in chambers lacking carbon dioxide in such manner as to permit normal development of etiolated organs in darkness in some species in confirmation of results obtained by Jost. The re- moval of concurrent organs likewise permitted the full development of organs in some species. The etiolation of a shoot sets in motion regulatory mechanisms by which useless leaves and other organs are cast off in some instances. Later a popular account of etiolations of flowers was published. F. Darwin” called attention to the adaptation theory of etiolation by Godlewsky, in 1896 and pointed out that, lack of light acted as a stimulus and also exerted an effect by disturbing nutrition. The instance of the germination of gemmae of Marchantiaceae only in light was given as in accordance with the theory in question. Klebs ™ observed the influence of light upon vegetative and repro- ductive processes of several algae and fungi. The formation of zoé- spores appeared to occur most frequently in diffuse light and dark- ness and conjugation took place in light, the intensity and duration of the illumination being factors in the influence. The blue-violet rays appear to be the cause of the specific action of light in such in- stances. The formation of zodspores by Oedogonium appears to be entirely independent of light, while on the other hand this process takes place only in light in Ulothrix. No generalizations as to ** Bonnier, G. Influence de la lumiére électrique continue sur la forme et la structure des plantes. Rev. Gen. d. Bot. 7: 241, 289, 332, 407. 1895. ** MacDougal, D. T. Relation of the Growth of Foliage Leaves and the Chloro- phyl Function. Jour. Linn. Soc. 31: 526. 1896. ' Darwin, F. Etiolation as a Phenomenon of Adaptation. Jour. Roy. Hort. Soc. IQ)? 345. | 1806. . ne Klebs, G. Die Bedingungen der Fortpflanzung bei einigen Algen und Pilzen. 1896. MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 29 retarding effect of light as a direct action may be drawn from these observations. The observations of Stameroff " offer some important and accurate evidence upon the influence of light upon the growth of fungi. Veg- etative hyphae of Mucor and Saprolegnia show the same rate of growth in light and in darkness, while light is found to retard the elongation of the sporophores of Mucor in corroboration of Vines’ experiments upon these organs, but it was not made clear that such retardation was not due partially or wholly to altered transpiratory conditions. Similar retarding action was observed in rhizoids of M/ar- chantia polymorpha. The growth of pollen tubes of Colutea arbo- rescens and Lobinia pseudacacia was not affected by light. Mucor flavidus was seen by Lendner ™ to produce spores only in light; AZucor racemosus developed sporangia in darkness but ma- tured spores only in light. Many species of moulds were found to show an excessive elongation of the sporophores in darkness. Curtel *’ made extensive observations upon the influence of diffuse light upon flowers. He concluded that flowers were less brilliant in color, and fewer in number, and that the peduncles were longer and more slender in diffuse light than in directillumination. The corolla showed the greatest amount of change, and the stamens and pistils the least. The fruits were smaller and fewer in diffuse light. All of these manifestations might not appear in any one individual. Very diffuse light rendered flower formation impossible and strong diffuse light was quite as favorable as the direct rays. The reactions in question were ascribed to disturbances in nutrition. Green ” investigated the effect of light upon enzymes in plants and found that rays located in the red, orange and blue regions caused an increase in the amount of diastase present during the ear- lier part of the illumination and later acted deleteriously. The vio- let and ultra-violet rays exerted a constant disintegrating effect. The action of light upon the diastase or enzymes of a cell is, of course, greatly modified by the character of the external membranes, 1022 Stameroff, K. Zur Frage iiber den Einfluss des Lichtes auf das Wachstum der Pflanzen. Flora, 83: 135. 1897. 108 Tendner, A. Des influences combinées de la lumiere et du substratum sur le dévéloppement des champignons. Ann. Sc. Nat. VIII. 3: 60. 1867. 104 Curtel, M. Y. Recherches physiologiques sur la fleur. Ann. Sc. Nat. VIII. 6: 220. 1897. 15 Green, J. R. Action of Light on Diastase, and its Biological Significance. Proc. Roy. Soc. 188: 167. ‘1897. 30 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. and of the contents of the epidermal cells. The enzymes appear to absorb some of the radiations, but no conclusion is reached as to the fate of the energy transformed. Grantz'” reinvestigated the relations of fungi to light in 1898. Pilobolus formed sterile sporophores in darkness, and the same reac- tion in other fungi is cited. Etiolated sporophores of Pilobolus might produce spores if given only fifteen minutes’ exposure to light. Grantz suggests that the etiolation phenomena of fungi are, in fact, reactions to the specific stimulations of light or darkness, and that various correlations are exhibited in these reactions. A practical confirmation of the conclusions of Jost, MacDougal and others as to the ability of leaves to develop in darkness was made by Vogt,” who found that this might occur when these organs were relieved of competition with concurrent members. Similar behavior in atmospheres lacking carbon dioxide was observed, although the duration of the leaf under the latter condition was very limited. Illumination of etiolated seedlings was followed by the attainment of larger size than normal seedlings of the same age. A general repetition of etiolation tests by Teodoresco,’ in which entire plants were deprived of illumination, and in other instances branches were thrust into dark chambers gave some interesting results. Leaves borne on such branches always attained a greater size than those on entirely etiolated specimens. The number of stomata per unit of surface was smaller, however. The normal wavy outlines of epidermal cells in leaves unsually lacking in wholly etiolated plants were present to some degree in these etio- lated branches, in which also the mechanical properties of the tissues were more nearly normal than in entire etiolations, in ligni- fication and thickening of the walls. Solanum tuberosum, Atriplex hortensis, Faba vulgaris, Helianthus tuberosus, Humulus Lupulus, Phaseolus multiflorus, Cucurbita Pepo, Chenopodium album, Aster patulus, Cannabis sativa, and Saponaria oficinalis were used in these 'SGrantz, T. Ueber den Einfluss des Lichtes auf die Entwickelung einiger Pilze. 1808. '7 Vogt, C. Ueber Abhiingigkeit des Laubblattes von seiner Assimilationsthiatig- keit. Inaug. Diss. Erlangen. 1898. ‘08 Teodoresco, E. C. Action indirecte de la lumiére sur la tige et les feuilles. Rev. Gen. d. Bot. 11: 369, 430. 18cg9. Teodoresco, E. C. Influence des différentes radiations lumineuses sur la form et la structure des plantes. Ann. Sc. Nat. Bot. VIII. 10: 141-164. 1899. MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. Sr tests. The general subject was treated more fully in an extended paper in the same year in which the following additional points are made: Etiolated plants have the outer walls of the epidermis with- out the papillose convexities characteristic of other individuals of the same species grown in light. Intercellular spaces are lacking in mesophyl of etiolated leaves, and is composed of isodiametric cells. The palisade cells show some differentiation. Stomata were ob- served by Teodoresco to be more numerous in a given area than in normal specimens, and also to be smaller. The notable lack of differentiation of tissues in etiolated plants was observed and atten- tion was called to the lack of formation of the generative layers, and of secondary tissues. Similar lack of development of xylem and of *bast fibers was noticed. The multiplication of observations upon fungi in which light is found to exert no influence is a notable feature of the most recent investigations. Klebs"” joined in such results and found that growth of the vegetative organs as well as the reproduction of many forms was utterly uninfluenced by the radiations. Furthermore the growth of sporophores in many species occurred absolutely indifferently in light and darkness. The single instance of retardation of growth of the sporophore of Phycomyces and Mucor by Vines and Stameroft does not have the concurrence of Bullot,"° who affirms that these organs grow more rapidly in continuous light than in darkness. Light has been found necessary for spore formation except in the sin- gle example cited by Klein. In such observations the critical points are well defined and the intensity of illumination may be increased to a point where an unfavorable action is exerted, and the photo- tropic behavior reversed. Klebs has pointed out the necessity for the strictest control of experimental tests of fungi in light since the separ- ate results of altered transpiration and nutrition may mask or alter the effects of the illumination. These results are confirmed in the main by Ternetz,"’ and other investigators quoted by Klebs and Ternetz. Klebs, G. Zur Physiologie der Fortpflanzung einiger Pilze. Jahrb. f. Wiss. Bot. 35: 140. 1900. "9Bullot, E. Sur la croissance et les courbes’'du Phycomyces. Ann. d. 1. Soc. . Microscopique d. Belge, 21: 84. 1897. ™ Ternetz, C. Protoplasmabewegungung Fruchtkérperbildung bei Ascophanes carneus Pers. Jahrb. f. Wiss. Bot. 35: 273. 1900. 32 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. Brenner!” attributed the abnormal forms of succulent species of seed plants in darkness to disturbances of transpiratory conditions on one hand, in addition to an adaptive elongation of the shoot for the purpose of reaching the light. The investigations of Thomas’ in which instructive comparisons were made between the characters of subterranean and aérial leaves are of great interest. Leaves normally or experimentally developed as underground scales cutinize both upper and lower surfaces, and diminish the formation of collenchyma, palisade cells and intercellu- lar spaces. Decrease in vascular tissues, disappearance of projec- tions and irregularities of contour, diminished development of sieve tubes and stereome are also features of such growth, and are parallel to those shown in etiolation. Underground leaves may also lose the’ stomata when used for storage. Maige'* brought out some interesting observations on the geo- tropic reactions of creeping plants in darkness. ‘Two groups are dis- tinguished according to their reaction in darkness. One group, including Hveracium pilosella and Mentha sativa, places its branches in an erect position in darkness, and a second, of which Potentzlla reptans is representative, does not. Stegeoclonium tenue has been found to remain green and healthy in darkness for periods of three to five weeks, and such deprivation of illumination did not alter the response to the osmotic and nutritive influence of solutions, according to the observations of Livingston,” an endurance which is of interest in connection with the determination of the term through which chlorophyl may be maintained in darkness. Goff "° relates that the first node of seedlings of corn usually is to be found near the surface of the soil, regardless of the depth at which the seeds may be planted. Seedlings in darkness showed such elongation of the first internode that the node was raised some distance above the soil. "Brenner, W. Untersuchungen an einigen Fettpflanzen. Flora, 87: 387. 1900. '8Thomas, J. Anatomie comparée et expérimentale des feuilles souterrainnes. Rey. Gen. d. Bot. 12: 394. 1900. 'Maige, A. Recherches biologiques sur les plantes rampantes. Ann. Sc. Nat. VENT ri) 345.) 1900: 16 Livingston, B. E. Further Notes on the Physiology of Polymorphism of Green Algae. Bot. Gazette, 32: 298. 1go01. "6 Goff, E.S. Influence of Light on the Length of the Hypocotyls in Indian Corn. Science, 13: 395. 1901. MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 33 Ricome'” has made a series of examinations of the behavior of etiolated plants placed in light before deterioration of the shoot had begun and his chief results are as follows: The excessive growth in length of stems slackens quickly when etiolated plants are illumi- nated and the rate of growth remains slower than that of control specimens. If, however, abundant reserve material is at hand the rate is not sensibly slower than the normal, except at the beginning ofthe illumination. Mature shoots of illuminated etiolated specimens are longer than normal if such reserve material is present, but shorter otherwise. The internodes at the base of the hypocotyledonary axis are more slender than the normal in such plants unless ample reserve material is present. The basal internodes formed in darkness are elongated in light but the internodes formed immediately after exposure seem to be shorter than the normal, or those formed later above them, which have the normal length. This seems to be due to the disturbances in the transpiratory conditions. The number of leaves of illuminated etiolated specimens is less than in normal specimens. Etiolated plants without reserve food do not attain the normal weight when illuminated, although this is accomplished by plants with a reserve food-supply. Illuminated etiolated plants have a comparatively greater dry weight than normal specimens. If plants with reserve food are etiolated for a short period and then illumi- nated they will appear more vigorous than normal specimens for some time, a result that has been confined by Dr. H. M. Richards in some experiments in his own laboratory. Noll "8 concludes that darkness as such acts as a positive stimulus in producing etiolation phenomena and finds that similar reactions may be obtained from other causes, such as in the growth of roots in solutions lacking nitrogen. Phenomena resembling etiolation have been induced in algae by Benecke ' by the use of culture solutions lacking nitrogen. Wiesner ™ likewise was able to secure excessive elongations of 7 Ricome, M. H. Sur le développement des plantes étiolées ayant reverdi ala lumiére. Compt. Rend. 13%: 1251. 1900. Ricome, M. H. Action de la lumieére sur les plantes préablement étiolées. Rev. (Gened, Bot. 14: 26, 72, 120. :1902. U8 Noll, F. Ueber das Etiolement der Pflanzen. Sitzungsber. d. niederrheim Ges. z. Bonn., May, 1901. Abstract, Botan. Ztg. 60: 38. 1902. 19Benecke, W. Ueber Cultur Bedungungen einiger Algen. Bot. Ztg. 56: Ist Abth. 89. 1898. 1.0 Wiesner, J. Formanderungen von Pflanzen bei Cultur im absolut feuchten Riume. und im Dunkeln. Ber. d. Deut. Bot. Ges. 9: 46. 1891. 34 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. stems by cultivation of plants in chambers of low humidity, exter- nally resembling those resulting from etiolation. No anatomical com- parisons were made, however. By the recent researches of Nabowick™ etiolated seedlings of maize, sunflower and onion were found capable of anaérobic growth, although further evidence upon the matter is needed. Neljubow ™ describes the horizontal positions assumed by stems of Pisum and other plants in darkness and ascribes these positions to the influence of various external forces, the relations of which are 121 not made clear. Undoubted instances of growth which is accelerated or facilitated by light are given by Schulz” as the result of observations on spores of mosses, ferns and equisetums. Germination of these bodies are said to occur only in light with the exception of those of Ceratopteras thalictrotdes and the Ophioglossaceae. In some instances the stimu- lating action of the rays is necessary to start growth, while in others, growth must wait on the construction of material by the chorophyl apparatus before new Cells of protoplasm may be built up. It was found possible to replace the stimulating influence of light by that of other forces in a few instances. These results are in accord with those attained by Borodin™ thirty- four years earlier. Borodin tested the spores of Asfidium spinu- losum foenisecci, Aneimia Phyllitides longifolia, Allosorus sagittatus, Aspidium molle, Polypodium repens, Phegopteris effusa, Asplenium alatum, Asplenium lasiopterzs and another species of Asplentum and found that light was an indispensable condition of germination of these forms, the least refrangible rays being active in the matter, the blue rays having the same effect as darkness. Milde™ had previously reported that spores of Hguzsetum would germinate in darkness although this result has not been confirmed. No attempt has been made in the foregoing sketch to review the literature of influence of light upon germination of seeds. It is well 121 Nabowick, A. Wie die Fahigkeit der Héheren Pflanzen zum anaeroben Wach- stum zu beweisen und zu demonstriren ist. Ber. d. deut. Bot. Ges. 19: 222. 1901. ‘2 Neljubow, D. Ueber die horizontale nutation der Stengel von Pisum sativum und einiger anderen Pflanzen. Beih. Bot. Centralb. 10: 128. 19Ol. 123 Schulz, N. Ueber die Einwirkung des Lichtes auf die Keimungsfihigkeit der Sporen der Moose, Farne, und Schachtelhalme. Beih. Bot. Centralb. 11: S81. 19Ol. Borodin, J. Ueber die Wirkung des Lichtes.auf einige hodhere Kryptogamen. Mel. Biol. 6: 529. 1867. "Milde. Zur Entwickelungsgeschichte der Equiseten und Rhizocarpen. Nova Acta Acad. L. C. 23: 2. —I re ee? CO lL eee ee mr rLc—n— ne MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 35 known that illumination is indispensable to germination of some species, and that darkness is equally necessary for others. In both instances the stimulating effect is probably concerned, although the action of the heat rays is not eliminated. The foregoing résumé may be held to include notices of nearly all of the more important researches bearing upon the subject of this paper. Doubtless some worthy of notice have escaped the author’s attention, and still a few others will be referred to in the discussion in the closing section of this memoir. peOorn, PURPOSE AND METHODS OF THE PRESENT OBSERVATIONS. In the earlier investigations of the author’ upon the growth of plants in darkness, and in atmospheres lacking carbon dioxide, con- clusions of value concerning the relation of development to nutrition, and as to the regulatory action of the plant in darkness were reached. It was found, however, that a satisfactory explanation of the phe- nomena of etiolation might not be made from any such limited series of experiments, and that current generalizations as to the relation of light to growth and reactions of plants in darkness rested upon simi- larly isolated series of observations in which only a few species of plants were used, and under conditions not always under full control, It was therefore planned to carry out a large number of etiolations upon species selected to represent types of the most diverse morpho- logical and physiological character and habit. In the seven years during which the work has been in progress ninety-seven species have been cultivated in continuous darkness with control plants in ordinary alternation of daylight and night. Aquatics, creepers, climbers, succulents, mycorhizal forms, geophilous and aérial shoots, mesophytes and spiny xerophytes, were grown from tubers, corms, rhizomes, cuttings of leaves and stems, seeds and spores. By the extension of the observations over such an extended period, it was also possible to obtain much interesting and valuable information as to the inertia, or capacity for endurance of species with storage organs under conditions not suitable for the acquisition of formation of complex organic food, a subject hitherto but little touched. 1226 MacDougal. Relation of Growth of Leaves to the Chlorophyl Function. Jour. Linn. Soc. London, 1: 526. 1896. 36 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. The earlier etiolations from 1895 to 1899 were made at the Uni- versity of Minnesota in small portable chambers of zinc and wood, and the cultures were examined for a few minutes every day in day- light, a method which is found to offer results markedly different from those kept in absolute darkness and examined by the light of a single candle not oftener than once a day. For a portable chamber the best material was found to be zinc, and this was built in the form of a small house with no bottom. The entire chamber rested upon a bed of sand about 5 cm. in depth, upon which the plants were placed. The chamber was lifted from its position by means of a cord attached to the top passing over a pulley fastened to a beam above. Whenthe chamber was lowered to its posi- tion the edges were imbedded in sand in such a manner as to exclude light absolutely. Ventilation was provided by means of tubular openings to which sections of rubber tubing were attached. The curvatures of the tubing prevented access of light. Such portable chambers were protected from the direct action of the sun’s rays, and injurious temperatures were thus avoided. Upon my removal to the New York Botanical Garden in 1899 the work was resumed in a specially constructed dark chamber. This chamber measures 5 x 5 x6 meters and is situated in the middle of the laboratory suite on the fourth floor of the museum building, and is pro- vided with ample connections with ventilating shafts in such manner that the atmosphere is always normal. Cultures were made here between October and May of each year, and during this period the temperature was constant between 17 and 21° C., and did not traverse this range in less than four days, so that for most purposes a constant temperature was provided in these tests. It is to be understood of course that this temperature is by no means suitable for all of the forms upon which observations were made, a fact which was duly noted in the descriptions of the separate experiments ; it did permit, however, a fairly etiolated normal development of almost all of the species examined. Entrance to the chamber was gained by a set of double doors with a vestibule between in such manner that no day- light was admitted. Examination of the plants was made by means of the light afforded by a single candle, or an electric hand-lamp of four candle-power. In a few instances the etiolated specimens were removed for the purpose of making photographic negatives, but generally this ee MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 37 was not done until the completion of the experiment. Control speci- mens were cultivated in the physiological laboratory on the same floor of the building, or in the experiment chamber of the propagating houses. The illustrations are mainly drawings from photographic prints, from natural objects and from microscopic sections, and were made by Miss Alexandrina Taylor, and Mr. Auguste Mariolle. The details of the observations on the several species of plants brought under examination are given on the following pages. Agave Americana L. Specimens with thick fleshy leaves 25 to 4o cm. in length were placed in the dark chamber in September, 1900, and the observa- tions were closed in May, 1901. Leaves which had not reached maturity at the beginning of the test elongated by basipetal growth, forming a pale yellow etiolated basal portion. The chlorophyl in the older green portion was maintained in an apparently normal green condition during the entire eight months. Leaves emerging after the beginning of confinement attained only half the length and thickness of the normal, and were capable of extended existence in the dark room. This endurance is coupled with the fact that the stomata were present in the etiolated epidermis, open and apparently normal in form with the guard cells richly loaded with starch.” The leaves were not so rigid as the normal. The teeth along the margins were present, but were not so prominent as in the green specimens. The outer walls were slightly cutinized, less so than the normal, and did not show the usual thickening. The develop- ment of the fibrovascular bundles was apparently arrested in an early stage of the differentiation of the phloém and xylem. Spiral vessels were fully formed, however, and could be pulled out in the usual manner. No indications of flower spikes were to be seen in the etiolated plants, or in the control tests. Allium Neapolitanum Cyr. Bulbs of Aliium Neapolitanum were placed inthe dark chamber in March, 1gor and soon began to send out leaves. The bases of the 127 Thomas, J. Anatomie comparée et experimentale des feuilles souterrainnes. Rey. Gen. d. Bot. 12: 394. 8 1900. 38 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. leaves were sheathing and adherent to a distance of about 5 cm. from the bulb in both the normal and etiolated examples. Normal leaves were about 2 to 2.5 cm. in width are about 20 cm. long, being curved and twisted. Etiolated leaves attained a length about equal to the normal with inrolled margins and with a width of 12 to 15 mm. The curvatures and torsions were much more marked than in the normal, and the positions assumed were indicative of an entire lack of geotropic sensibility. It is to be noted that this plant offers an example of a monccotyledonous leaf which does not exceed any of the dimensions of the normal. A creamy yellow color points to the presence of a large amount of etiolin or carotin. Fic. 1. Allium Neapolitanum, etiolated, showing positions and forms assumed by leaves. % natural size. Sachs™ records that Allium Cepa developed etiolated leaves longer than the normal and variously divergent. Such leaves were thinner aa Sachs. Ueber den Einfluss des Tageslichtes auf Neubildung und Entfaltung ver- schiedener Pflanzenorgane. Ges. Abhandl. 1: 196. 1892. See also Sachs. Hand- buch der physiologischen Botanik, p- 38. 1865. MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 39 than the normal and were lacking the central lysigenous cavity, as were also those of A. Veapolitanum. The inflorescence axis showed no sign of activity and was wholly undeveloped in all examples dissected. After a growth of the leaves had been made in darkness, the outer scales from which they have been nourished were spent and empty. The scales composing the central core were solid and turgid forming an ovoid mass about I2 mm. in cross section. It is probable that these scales would have furnished material for the growth of the inflorescence in normal growth. Sachs speaks of the formation of seeds by Allium porrium, which presumably had more or less nearly reached maturity before confinement in the dark chamber. Allium vineale L. Bulbs of A. vzneale were brought into the dark chamber from the open air in April, 1900, and the leaves showed a rapid growth, soon reaching an ultimate size which was slightly less in length than in Fic. 2. Allium vineale. A, etiolated epidermal cells of leaf. &, normal epider- mal cells of leaf. > ICO. the normal. In a few instances the average measurement was reached, however. The width was less thaninthe normal. In con- trast to A. Cepa and A. Veapolitanum the lysigenous splitting of the internal parenchyma was observed to take place in the usual manner. 40 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. The epidermal cells were much longer and narrower than in the normal, which was also true of the guard cells of the stomata. The latter showed a narrow slit, and were slightly functional. The ex- istence of the leaves covered only a few weeks. The exaggerated length of the epidermal cells in this species is seen not to be accom- panied by a corresponding increase in the measurement of the length of the leaf, hence the number of epidermal cells developed must be smaller than in the normal. The inflorescence axis failed of devel- opment entirely. . Amaryllis Johnsoni Bury. Awakening bulbs of Amaryllis Johnsonii placed in oe dere chamber in April, 1901, showed a fairly normal elongation of the scape. The flowers opened in the usual manner with the pistil extruded to a length of 2 cm. beyond the stamens. It is to be noted that the unopened flower bud in this instance was subject to the action of light for some time before growth began, and that ample opportunity was afforded for the exercise of a stimulating effect. Amorphophallus Rivieri Dur. A large corm of Amorphophallus Riviert was placed in the dark room in a resting condition in March, 1900. The soil was allowed to become slightly drier than that necessary for germination until September, 1900, when water was applied daily. The flower bud opened in October and the scape began to elongate at a rate which increased until it amounted to 20 cm. one day and 25 cm. on another, after which the rate decreased to minimum. A total length of 1.8 meters was reached within three weeks. The three sheathing scales at the base of the scape were 12,22 and 35 cm. in length, which is much greater than that of the normal. The attainment of full length of the scape was marked by the appearance of the roots from the upper internode of the corm, these organs being entirely dormant until this time. ‘The development of the scape and flower was accompanied by a striking display of color. The scape was slightly fluted, pale red in color with mottled patches of violet, and exuded sap freely when cut across. The spathe was only slightly flaring at the top where it was a deep rose purple, shading lighter to the base, where it was a pale rose tint. The spathe reached a length of 40 cm. and the inner surface .of the lower portion was deeply rugose and purple for a distance of ee eta As MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. io cm. from the base. The pistillate flowers oc- cupied a zone about 8 cm. long on the spadix, and were flaccid and pale rose color. The staminate flowers occupied a zone 7 cm. wide above them, and were of a brownish hue. Both stamens and pistils did not reach normal development and were not capable of carrying out seed-formation. The irregular club-shaped end of the spadix was hol- low by reason of the central cavity of lysigenous origin. The portion of the spadix above the flowers was 50 cm. in length and became curved at matu-. rity while still turgid.and firm. The spathe was seen to be furnished with many stomata, which were open when examined in water, and the guard cells of which were richly loaded with starch. Similarly developed and active stomata were found on the epidermis of the scape. The characteristic unpleasant odor of the plant was noticeable, but not so strongly as in examples grown in light. The scape and the flower endured for a period of about five weeks from the beginning of growth and then quickly perished. Immediately a swell- ing bud at one side of the base of the scape began to increase in size very slowly. The corm was allowed to go into a resting stage in May, Igor, and again watered and given favorable cultural conditions in September, 1901, but the slow in- crease of the bud ceased and no leaf had been de- veloped as late as May 27, 1902. This bud occu- pied the position of the leaf, which ordinarily begins growth after the maturity of the flower, and con- temporaneously with the growth of the roots. The growth of the roots in an etiolated specimen con- tinued more or less freely during the entire period after their first appearance. The corm was taken from the soil on the last named date, and in addi- tion to a great number of rudimentary buds Fic. 3. Etiolated scape of Amorphophallus Rivieri. Aspect of plant, including corm, upon maturity of scape and before _ curvature of end of the spadix had begun. 41 42 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. and roots had formed two large branches of a corm-like struc- ture. The apices of these branches were crowned with long buds curved apogeotropically, and containing a young leaf. The failure of the scape to reach light from the opposite, upper surface, may have stimulated the formation of these leaf buds from the lower side. The scape shows an exaggerated elongation, in conformity with the fact that it must find its way up to the light unaided under all circumstances. The soundness of the corm after the first growth in darkness suggests that it might be capable of long-continued exist- ence without light after a manner more fully described in the discus- sion of Arzsaema. Apios Apios (L.) MacM. Tuberous stems of Afzos were placed in the dark chamber on February 14, 1900. These specimens had remained in the soil in the open during the preceding winter months and the shock of the Neel Jy, s MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 45 the cambium and the bast fibers was occupied by a mass of elongated parenchymatous cells with large lumina. The bast fibers were to be made out but were very sparingly thickened. Externally to the bast cory so Fic. 6. Apzos Aptos. Transverse section of portion of aérial normal stem; 4, epidermis; B, cortex; D, bast fibers; £, cambium; /, xylem; G, pith. X40. was a tract of two to five layers of cambiform cells which seemed to be very active. The formation of this secondary generative region is certainly a remarkable occurrence, and is one which finds a paral- lel only in Castanea, Hicoria and Quercus among the species examined (see Fig. 7, C). Fic. 7. Apios Apios. Transverse section of portion of etiolated stem; A, epi- dermis; B, cortex; C, generative layer; D, bast fibers; E, cambium; F, xylem; G; pith. X 40. 46 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. Nearly all of the tubers from which etiolated stems were devel- oped in these cultures survived and contained a large amount of storage material, and some of them showed a second growth similar to the first, without perishing. Agzos may be classed as a plant capable of making more than one effort in different seasons to carry leafy stems up to sunlight. Aplectrum spicatum (Walt.) B.S.P. Fourteen vigorous specimens of Aplectrum spicatum were placed in the dark chamber on December 27, 1898, and soon awakened. Leaves were formed which reached matur- ity in May, 1899. Similar cultures were also made in the following year. These leaves were formed at the extremities of offsets which run 2 or 3 cm. laterally from an old corm and then develop the terminal internodes as a corm with its apical bud apogeotropic. The leaves are put out during the season of swell- ing of the corm. The young corm receives storage matter both from the old corm and from the active new leaf. Inthe etiolated specimens the corms thus formed attained about twice the length of the nor- mal, with the longitudinal diameter much greater than the transverse, which is the reverse of the normal behavior. Fic. 8. Aflectrum spicatum. A, etiolated plant with young corm, scales and attenuated leaf. £4, old corm and young corm formed in darkness. C, inflorescence of etiolated plant. WZ, single etiolated flower. f Met egg MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 47 The outer and lowest sheathing scale attained a length of 3 cm, and the scale from the median node of the new corm was 9 cm. long, while the leaf arising from the upper end of the terminal node attained a length of 25 cm., which is about double that of the nor- mal. The excessive development is distributed throughout the entire length of the leaf, so far as my examinations may be depended upon. The upper portion remained folded plicately in a cylindrical mass a few millimeters in diameter, and the total width when arti- ficially extended was not more than one-fourth of the normal. Numerous stomata were formed which were open when examined in alcohol. About the time that the leaves reached maturity, offsets from the young corm were sent off, which in some instances had the coralloid form taken in certain mycorhizal adaptations which I have previously described. The development of the leaves usually occurs at the close of a vegetative season, and these organs live through the winter, falling away in the spring, when the scape arises axially to the leaf scars. In the etiolated examples, however, the development of the leaves covered a period from December 27 to May following, and the in- florescences began to push up in March before the growth of the leaves was completed. The flowering branch is composed of two or three internodes. From the upper end of the uppermost internode a scale 8 to 15 cm. long arises completely sheathing the flower bud, its edges being fused to form a complete covering. An inner scale with a length of 6 cm. also sheathes the flowers in the same man- ner. These two scales remain intact and the flowers perish with- out being exposed to the air. The separate pedicels attain a length about a half greater than the normal, and the floral envelope in the separate flowers is much reduced, although the pollinia appear fairly normal in stature. A third outer sheathing scale inclosing the inflorescence is pushed open by the flower bud with its double coat. Etiolated corms made a second growth in the dark chamber after a resting period of four months. The second series of etiolated leaves were smaller than the first. No flower buds were formed. Many of the corms were seen to be alive after the second growth in the dark, but no further action could be secured from them. MacDougal. Symbiotic Saprophytism. Annals of Botany, 13: 1. 1899. 48 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. Arisaema Dracontium (L.) Schott. Corms of Arzsacma Dracontium were placed in the dark chamber in 1897, 1898 and 1899. After a proper resting period had been given, the terminal buds would begin to enlarge about five weeks later, and roots were sent out from the upper internode which pene- trated the soil in all directions. These roots as well as those of Amorphophallus and other aroids often emerged into the air, and were only directed back into the soil after a length of a centimeter or two had been exposed, as if the sole directive force were moisture. Ny my | i bie jn “a eS i oe c Fic. 9. Culture of etiolated plants of Ardsaema Dracontium, showing several stages of development of the buds, scapes and flowers. After about five weeks from the beginning of the culture the buds reached a length of 25 to 30 cm., at which stage the prophyll, which had hitherto completely enclosed the leaves and flower, would split and an elbow or curved portion of the petioles of one of the leaves MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 49 would be thrust out. After a time the leaves and flowers would become entirely freed from the bud. The leaflets remained tightly folded together and were of a rich yellow color. The spathe re- mained tightly wrapped around the spadix, was smaller than the normal and also of a pale yellow color. The scape did not attain a length comparative to that of the petioles. Normally the attenuated tip of the spadix is thrust out above the leaflets, but in these etiolated examples it remained much shorter. The etiolated spadices were about normal length. The stamens and pistils did not reach normal stature, and attempts at pollination met with no result as to seed formation. Fic. 10. Arisaema Dracontium. A, epidermis of normal scape. B, epidermis of etiolated scape. C, epidermis from lower surface of normal leaflet. D, epidermis from lower surface of etiolated leaflet. >< I90 The scapes and scape were more slender than the normal. The altered dimensions of the epidermal cells did not correspond to these changes, however. Measurements of a number gave an average length of 38 for the normal and 32 for the etiolated epidermal cells of the scape. The width of normal cells was 1o and of the 50 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. etiolated 11. Stomata of normal scapes measured Io by 12 in one series and 10 by 11 in another. Stomata of etiolated scapes meas- ured 8 by 10 and 8 by 11. The stomata were slightly open when examined in water. Corms surviving the first etiolation were given a period of rest, when they were again set in action, and produced buds of not more than half the length of the first etiolated growth. No flowers were formed inthis second etiolation, however. Many of the corms were sound and alive after the second etiolation, and remained quiescent two years and are still dormant at the date of preparation of this memoir (June, 1902). Attention has been called to the saprophytic etiolated growth of the seedlings of Arzsaema Dracontium in a previous paper. The ger- mination of the seed results in the formation of a hypocotyledonary stalk which is pushed down into the soil carrying with it the plumule which remains in an undeveloped condition. The base of the hypo- cotyl soon begins to swell and the surplus food in the seed is with- drawn into the tuber thus formed, which bears the quiescent plumular bud at its apex. The entire season is thus spent underground, and the saprophytic existence of the seedling is much prolonged.” Arisaema triphyllum (L.) Torr. Arisaema triphyllum \ent itself most readily to etiolation experi- ments and it was used in obtaining data on several general questions in the investigations. Several hundred cultures have been made in the dark chamber, and this plant has been under continuous observa- tion from 1895 to 1902. Corms placed in the dark chamber ates a proper resting period would soon begin to show indications of activity. Ordinarily the terminal bud of the corm elongates to a length of 5 to 7 cm. and then splits, allowing the leaves and flowers to escape. The sheath- ing bases of the two leaves enclose the base of the scape to a dis- tance of 4 to 8 cm. from the corm, and the petioles attain a length _ of 15 to 75 cm., which is something longer than the scape. A second scale sheathes the base of the bud and has a length of 2.5cm. A third basal scale rarely reaches a length of over a centimeter. Marked departures from this procedure were shown by etiolated cul- 130 Mac : eS) Ce . ’MacDougal. Seedlingsof Ar/saema. Torreya,1: 2. 1901. See also Rennert, R. J. Seeds and Seedlings of Arisaema triphyllum and Arisaema Dracontium. Bull. Torrey Club, 29: 37-54. 1902. “= vw MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 51 tures. The prophyll elongated excessively, attaining a length of 8 to 50 cm. before it splits for the emergence of the leaves and flower. The second scale attained a length of 4 to 7 cm. and the third about half that length. This test was made in another form by placing =—— = Fic. 11.8 Arisaema triphyllum. Normal, with two latera plantlets. plants with awakening buds in an exposed situation and covering the buds with a heap of sphagnum to a depth of 30 cm. Similar elongation of the prophyll was made and the bud was not opened 52 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. till the tip of the prophyll had been stimulated by light. Still a third experiment was made to determine the capacity of the plant for piercing obstacles between its bud and light; a number of corms were buried to a depth of 25 cm. in loose garden loam and the pro- phyll reached the surface of this substratum before opening. The mechanical force exerted must have been very great. Fic. 12. Arisaema triphyllum. A, plant grown in portable dark chamber with occasional exposure to diffuse daylight. B, etiolated bud shortly after opening: an apical portion of the prophyll is borne on the tips of the leaf. Roots were not sent out from the crown of the corm until about the time of the maturity of the leaves. The petioles are normally about equal in length, but in etiolated cultures one was often much longer than the other. The laminae did not unfold when the cultures MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 53 were made in absolute darkness. It was noted, however, that etiola- tions made in the small portable dark chambers, which were ex- amined daily in an exposure to sunlight for two or three minutes showed a different stature for the leaves. In such instances the laminae were extended in a plane and had a superficial area of about half that of the nor- mal. This result has been verified by repeated obser- vations and suggests that etiolative reactions must be accepted with caution uniess known to have been secured in a total exclusion of day- light. This caution takes on special emphasis from the fact that such vitiated etiola- tions may not show the pres- ence of chlorophyl. Sachs’ criterion of perfect etiolation is therefore not one which may be depended upon in all Species. (See Fig. 12.) The scape of the flower showed excessive elonga- tion and the spathe did not reach normal size, the great- est decrease being located in the overarching hood. The spathe retained its red- dish and purplish colors in fairly normal depth so far as comparisons might be made. In some instances the hood showed a strong Fic. 13. Arzsaema triphyllum, grown in almost absolute darkness. epinastic growth by which it was recurved outwardly, and in nearly all instances it was more or less nearly erected. (See Fig. 13.) MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 54 Fic. 14. Arisaema triphyllum, showing development of culture in Fig. 13 after exposure to daylight for two weeks. MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 55 Stomata were formed in the epidermis of the etiolated prophyll, which were open when examined in water, and the guard cells con- tained much starch. The length of the epidermal cells in the prophyll was to that of the normal as 18 to 12. Similar relations were found in the epidermis of the petioles, while the epidermal cells of the scape did not differ widely from the normal in measurement. It is to be seen therefore that the excessive elongation of the aérial organs of Arisaema triphyllum is accompanied by a multiplication of the epidermal elements, which are of slightly increased size. The sur- face of the prophyll is covered with rods of waxy exudation in the normal, which are lacking in etiolated specimens. (See Fig. 16.) Upon the maturity of etiolated aérial organs the plastic material was withdrawn into the corms, which increased by a thin layer above and cut off a thicker layer below, so that upon the ripening of the corms they were smaller than at the beginning of the test owing to the consumption of some of the material in the work of growth and transpiration. The alterations in the chemical composition of the aérial shoots and corms are shown in the analyses given below. After a resting period of a few months the corms might again be started into renewed activity which resulted in the formation of one, or sometimes two leaves only, with no flower. Third and fourth etiolations might be made in the same manner, in which only single leaves of diminishing size were formed. Half of the original num- ber of corms survived the third etiolation, and a small proportion were still alive and apparently sound after the fourth in darkness, but no further growth could be secured from them. It is probable with more attention to cultural details of temperature, especially dur- ing resting periods, that even longer endurance to deprivation of illumination might be observed. The resting periods were shortened by the treatment given the plants in such manner that four growths were made in three calendar years. The repeated growth in the dark was generally in the same ter- minal bud, but in some instances its destruction would result in the accelerated increase of two of the lateral buds which formed two small corms at the expense of the older one. It was noted in the repeated etiolations that the formation of roots was very sparing, the chief energy of the plant being directed to the construction of petioles. The germination of seeds in darkness is followed by the forma- tion of an etiolated leaf, which has a petiole longer than the normal 56 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. and an undeveloped lamina. The leaf quickly perishes and all of the plastic material is withdrawn into the newly formed tuber. Such small tubers may be started into activity after a period of rest, and may form a second leaf which also perishes during the forma- tion of the second tuber or corm. A third growth in darkness might be made, but the corms formed afterward were incapable of further endurance or existence. (See Fig. 15.) PIG. 15. Arisaema. triphyllum. A, seedling after first etiolation. &, seedling after second etiolation. C, seedling after third etiolation. D, adult plant after fourth etiola- tion, from corm. * The capacity of Arzsaema by which it is able to construct leaves both from corms, and from the seedling stage in darkness during three and four successive seasons is a remarkable fact, and is illustrative Fic. 16. Arisaema triphyllum. A, surface view of epidermis of normal petiole, B, surface view of epidermis of etiolated petiole. C, epidermis of normal prophyll. D, epidermis of etiolated prophyll. Z, etiolated flower. 58 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. of the immense reserve energy of plants with storage organs. Such an adaptation would be of great value in plants growing in loose moist soil in woods and meadows. The corms undoubtedly are often covered with soil, humus, or dry leaves to great depths. In such instances the power of excessive elongation of the prophyll would enable the plant to make a strong effort to emerge from such unfavorable conditions, and failing in the first attempt, the trial might be made a second, third, and even a fourth time, with greatly increased chances for survival over the plants which must win’ tne light in the first attempt or perish. (See Fig. 12.) Cultures were made in very diffuse daylight in which the tem- perature was exactly the same as of others in direct sunlight. It was found that the petioles did not show an elongation beyond that of the average normal specimen, but the laminae were reduced be- low the average in superficial area, and assumed a curved position. The overarching hood of the spathe assumed the upright position characteristic of the etiolated cultures. (See Fig. 17.) A number of studies of the method and rate of growth of the peduncles and petioles were made. To determine the region of maximum elongation, intervals of a centimeter were marked on the petioles and scapes and these intervals remeasured at maturity. The following final lengths show the locations of the greatest growth. PETIOLE. Basal, 3 cm. 6 7 12 10.5 4.5 Terminal. SCAPE. Basal, 7 cm. 5 4 5 Terminal. It is to be seen that the greatest elongation of the petioles takes place in a region above the middle, while it is basal in the scape. Peduncles and scapes have been attached to various auxanome- ters during the course of the experiments, extending over five years and the results, in so far as to periodicity and maximum elongation, have been fairly uniform. A consideration of the facts thus ob- tained forces one to the conclusion that the growth of the pedunclé and petiole in light is not characterized by any periodicity depen- dent upon, or influenced by light. The rate of growth was found to increase after 10 A. M. in most instances, or a short time after a rise in the daily temperature customary in greenhouses, which as an after-effect culminated at6or8 P.M. Lesser maxima were induced MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 59 by unusual variations in temperature. No marked periodicity could be detected in the rate of growth in the dark room kept at a constant temperature although slight fluctuations were seen. Similar irregular fluctua- tions in the rate were observed in the growth of the prophyllin darkness. The fluctuations in the dark room might be accounted for partly by the daily addi- Fic. 18. Arisaema triphyllum. Adult plant after confinement in dark room Fic. 17. Artsaema triphyllum. Grown in diffuse light. two weeks. 60 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. tion of water to the cultures, which was given as the state of the cultures seemed to demand it. The same influence would also be operative in the illuminated cultures. It is therefore certain that Arisaema triphyllum does not exhibit a daily periodicity of growth. independent of variations in temperature, and that the rate is not notably influenced by light; if light does retard, or accelerate the rate it is masked by the superior influence of temperature and trans- piration (see Figs. 19, 20, 22, 23, 24 and 25). Petioles and scapes which had ceased to elongate at a rate of more than a fraction of a millimeter daily were removed to the dark room when the temperatures of the illuminated room and dark room were equal, and growth was quickly renewed, an elongation of 14 to 16 mm. being made in four or five days. Such additional growth was undoubtedly facilitated by the higher relative humidity of the dark room, but must have been induced by the stimulation of dark- néss (see ie. 25). Etiolated specimens which had attained maturity were brought into a lighted room and found to be capable of expanding the leaf- lets, which however did not attain the average size of normally developed organs. The erect and recurved hoods of the spathes retained these positions. Variations in the final positions of the leaf- lets and general aspect of such illuminated etiolations are shown in Fig. 14. In one instance a second flower scape was developed from an etiolated plant after being brought into light. DETERMINATION OF WATER, DRIED MATERIAL AND ASH. The following series of determinations were made to ascertain the relative proportion of the main groups of constituents in normal and etiolated material. I Resting corms in a dried condition were placed in a moist cham- ber for a day, after having been out of the soil for three months. The outer dead coats were rubbed off with a cloth, and a corm of medium size with the half of one of the maximum size were weighed, and the various desiccations and combustions gave the following data ; Weight of fresh material 13.995 grams. A air Chae rie eld pe 3.400°" =e ae ‘¢ ash 108 "*s MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 61 Proportion of water 66 66 dry matter 66 66 66 66 66 66 66 66 GG ic dried 66 i not including ash ash in fresh material 75.65 per cent. ea-a0 a 24.29 v6 77 66 2.18 we Leaf and petiole of a green plant cultivated in greenhouse ; Weight of fresh material a ** dried me 6 66 ash 66 Proportion of water in fresh material 66 ‘¢ dried matter 66 ‘¢ ash in fresh material 66 66 66 66 dried 66 Corm of Above Plant Weight of corm ‘¢ =66 dried material 66 66 ash Proportion of water in fresh material 6s oe 66 ‘¢ ash in fresh material 66 66 Gen 66 dried oe III dried matter in fresh corm 5-441 grams. 484 °% . otf 82.50 per cent. P75 eos nee 200) sctnmunae 1.633 66 66 62 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. IV Air-dried seeds collected from fruits grown on plants in the open were cleaned and dried in air at ordinary temperatures ; Weight of material 3.619 grams. ss = St dried matter 3.320: 05 Ct teash 059 Proportion of water 8.27 per cena ae ‘¢ dried matter Giang - bie ‘¢ ash in fresh material 1.63 a, We 6 Xl t) ~ Aster divaricatus L. Rootstocks of Aster dvaricatus were brought into the dark room in February, 1900, and soon showed a rapid growth of the shoot. Fic. 33. Aster divarica- Etiolated stems attained a height of about 35 pd ones leaf. B,eti- cm. which is not far from the average of the normal plant. Fifteen leaves were formed on a typical specimen, with petioles about 5 to 6 cm. long. The laminae were about 2 cm. long and 1 cm. wide when unrolled. The upper surfaces (inner surfaces) remained appressed together, only — partially separating in a few instances. The petioles held a position from 30 to 40° from the vertical, or rather from the stem. The hairs on the normal stems were equally abundant on etiolated organs. EEO MEMOIRS OF THE Normal stems _ have several collenchymatous subepidermal layers, But one or two layers of subepidermal tissue were thickened in the etiolated culture, and only to a slight extent. The inter- cellular spaces were quite as well marked in etiolat- ed cultures as in normal. The bast fibers were only slightly thickened and no cambium layer was formed in etiolated cul- tures. [Full differentia- tion of the sieve cells was not accomplished. The bundles are separated by feeeneeee seeteeeeene steneverLaves Fic. 35. Aster divaricatus. in mig: 34. Partial trans- verse section of etiolated stem. Description as NEW YORK BOTANICAL GARDEN. 79 Fic. 34. Aster divaricatus. 1, partial transverse section of normal stem. 2, partial cross-section of etiolated stem. A, epidermis. JB, collenchymatous C, cortex. JD, bast fibers. A, cambium. G, pith. wide primary medullary rays, and the formation of secondary tissues had not begun in etio- lated stems. The xylem shows a development arrested before the vessels had reached nor- mal condition, and the pith lacked some of the intercellular spaces found in the normal. Etiolated shoots did not sur- vive very long and the earlier leaves quickly disappeared before the older ones were formed. Results similar to the above were obtained from an un- known species which was cul- tivated later. 80 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. Baccharis halimifolia L. A number of shrubs of Paccharis were brought from salt marshes of Staten Island, in November, and placed in the green- houses and dark chambers. These shrubs were about 140 cm. in height. Within a month a number of the buds about the base of the main stems began to grow and de- veloped slender etiolated stems, which bore small lanceolate leaves and which attained a length of a few centimeters and then perished. Bicuculla cucullaria (L.) Millsp. A number of the scaly bulbs of Bzcuculla were placed in soil in the dark room in January, 1900, and soon showed leaves. The petioles attained a length of 10 to 18 cm., and the terminal portion immediately below the lamina was curved through a complete revolution in such manner that the undeveloped com- pound lamina was held in a position varying between the inverted vertical and horizontal. The new bulbs formed at the bases of such etiolated leaves were only half the size of the normal, and were entirely free from coloring matter. No unfolding of the compound lamina was shown and the leaves soon perished. A second growth could not be induced. The average length of the epidermal cells of the etiolated petioles was double that of the normal. The " _ palisade tissue on the upper (inner) side of the lami- Fic. 36. Etio- ats : : lated leaf of Bicu. NA€ Could be distinguished, but the remainder of the culla with bulbous parenchymatous tissue was closely packed, and no enlargement —_at stomatal organs were found, a fact in correlation with iisiae the short duration of the etiolated leaf. The width of the epidermal cells remained exactly the same in etiolations and the increase was shown wholly in length. Botrychium obliquum Munt. Rootstocks of Botrychium were placed in the dark room in Oc- tober, 1899. The stipe attained a length of 18 cm. below the point where it divided into two branches, one of which was again divided, at a distance of 1.5 cm. The three branches thus shown were 9; MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. SI 10, and 16 cm. in length respectively, and only the larger one devel- oped lateral branches of noticeable size, but all had a cluster of foliar rudiments at the extremities of the pinnae. A spore-bearing pinna usu- ally arises from the stipe near the point where it branches, but in the etiolated cultures this organ was represented by an atrophied structure near the base of the stipe. The stipe was much longer than the normal, and the exces- sive growth was seen to take place in the upper part of the main stalk and in the adjacent bases of the branches. The diameter of the stipe was something greater than that of the normal organ. The upper portion of the stipe has two schizosteles of crescentic cross-section with the concavities facing each other in the normal, and distinctly separated by masses of fundamental parenchyma. The etiolated stipe had two large schizosteles almost confluent at the margins in much the same manner as the structures in the basal portion of the normal main stipe. The thickening of the normal epidermis is noticeably lacking in the etiolated stipe. The paren- chymatous cells ‘are slightly larger and with thinner walls in the etiolated specimens. Fic. 37. obliquum. Etiolated culture of Botrychium The sclerenchymatous tissue shows but little thickening in the etiolated stipes, and a similar lack of devel- opment is to be seen in the xylem, in which the walls are hardly half the diameter of the normal. Stomata, which are open when examined in water, are present 82 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. in etiolated stipes, and the epidermal cells are excessively elon- gated, showing a length of 20 as compared with 12 in the normal ex- amples. In this instance the epidermal cells appear to keep pace with the excessive growth of the stipe, although such correlation is of doubtful significance. Some chlorophyl was present, giving the etiolated specimens a distinct green color, in accord with the be- havior of all other ferns examined. Torsions were observed in the stipes of all etiolated examples of Botrychzum. It was also notice- able that the midribs of the pinnae were thicker than in the normal. The grooves usually present on the upper surfaces of normal midribs were lacking in etiolated specimens. Bowiea volubilis Harv. Bowiea volubilrs is a singular type of a xerophyte. It forms a large bulb with heavy green scales, from the central axis of which usually arises a scape I to 2 meters in length, bearing small lilia- ceous flowers. The base of this aérial shoot is usually sheathed with two or three small bract-like leaves which arise from it at points below emergence from the scales. Fic. 38. Etiolated culture of Bowzea and normal branch. Bulbs, which had rested properly during the summer of Ig00, were placed under cultural conditions in the dark chamber in Sep- tember. ‘Three shoots were sent up from a single bulb, reaching a Etiolated shoot, single leaf, epidermal cells of Fic. 39. Brassica campestris. lamina, and elongated epidermal cells of petiole. 84 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. length of nearly a meter, bearing branches or buds at distances of 3 to 8 cm., the distance from the bulb to the first and lower branch being slightly in excess of that of the normal. In some places, how- ever, the intervals were so short that three or four branches were crowded on a portion of stem not more than a centimeter in length. In some instances the buds developed branches 6 to 8 mm. long, sub- tended by small bracts of equal length. A bract about 7 cm. long, perfectly white, was formed at the base of each stem, being about double the normal length.™ A comparison with the normal shows that an excessive elonga- tion has taken place in the basal portion of the shoot, and that the development of the terminal portion has been hindered and the growth of the branches almost totally suppressed. The plant is normally a twiner, clinging closely and firmly to supports, but the eti- olated specimens were unresponsive to the pres- ence of vertical supports and were held to it by means of cords. The terminal portions of the stems exhibited an apogeotropic reaction. The thickening of the outer walls of the epi- dermis was notably less in the etiolated examples. Stomata were present, and were open when exam- ined in water. The layer of parenchymatous tissue beneath the epidermis, which usually contains many chloroplasts and starch granules in the nor- mal plant was almost free from plastids and solid bodies of all kinds in the etiolated examples. The sclerenchyma ring internal to the cortical tissue is but slightly thickened, and the fibro vascular tissues show but little development. Brassica campestris L. Large turnips were placed in the dark room in February and the leaves were soon sent out, grow- ing very rapidly and attaining full size by the end a of March. ‘The shoots reached a total height of Fic. 40. Etiolated 4 Kk culture of Avodes. 55m. Leaves attained a length of 13 cm., of which 4-6 cm. lay in the petioles. The narrow laminae i ial iid ace = oI if BN | ‘ sll HI! ? cea Pac tit | sal ‘S| For a general description of the development and growth of Bowzea see Buche- nau, F., Die Wachstumsverhiltnisse von Bowsea volubilis Hkr. fil. Abhandl. d. Naturw. Ver. z. Bremen. 6: 433. MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 85 were pale yellow and endured less than a fortnight, the entire shoot perishing very quickly. The epidermis both of the laminae and of the petioles showed excessive elongation, and also perfect and open stomata, in addition to large numbers of these organs which did not reach the stage of full differentiation of the guard cells. The fleshy roots perished quickly after the death of the leaves. Caladium esculentum Vent. Corms of Ca/adium placed in the dark chamber in February, 1900, soon began to send up a succession of leaves with petioles 1 to I.3 meters in length, with the laminae only partly unrolled. These laminae showed an extension of 25 cm. in length and 15 cm. in width when flattened out. The epidermal cells of the laminae Fic. 41. Etiolated leaves of Caladium esculentum. were very nearly the same as the normal in general size and outline, but those of the petiole were excessively elongated in a degree fairly correspondent with the petiole. The production of the etiolated leaves continued without interruption for a period of about 20 months, when the main bud perished, and activity of the lateral buds was exhibited in the same manner for some time. 86 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. It is to be seen that Caladium is capable of making a sustained effort to carry its chlorophyl surfaces up to light by means of the comparatively enormous amount of energy stored up in its large corms. A second series of cultures gave approximately similar re- sults, and the behavior of this plant is much like that of Arodes, to which it is closely similar in form and development. Fic. 42. Epidermis of petioles of Caladium esculentum. A,normal. B, etiolated. Calla (cultivated). Large corms of Arodes (Calla Aethiopica) placed in the dark chamber in November developed two large leaves and a flower stalk within a month. The flower did not reach the advanced stages of Arisaema, and the spathe remained tightly wrapped about the spadix. The leaves quickly died down, and a succession of these organs was formed continuously with no apparent resting period for nearly a year, when, the corm being nearly exhausted, death ensued. The leaves” showed some chlorophyl under the conditions in which most of the species examined were entirely blanched, except the ferns (Fig. 40). The following comparative analyses of the aérial organs were made ; ETIOLATED LAMINAE AND PETIOLE. Weight of fresh material 5-520 66 ‘6 dried 66 +399 a ‘¢ ash, .027 3 Percentag2 of water 92.77 | sc ‘* dried matter 7-23 sc ‘* ash in fresh material +049 % ts “6 66 dried 66 6.76 Norma LAMINA AND PETIOUE. Weight of fresh material 4.290 te 868. dried 66 +440 “ash, .031 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 87 Percentage of water 89.73 “ *¢ dried matter 10.27 “6 ‘* ash in fresh material 72 66 66 GG 66 dried (73 7.04 Calla palustris L. Rootstocks of Calla palustris were taken in a resting stage in April, and placed in dishes of water and mud in the dark chamber in April. The plant is a native of bogs and often grows in the mud at the bottom of shallow pools. Etiolated leaves had laminae slightly less than the normal, while the petioles was somewhat elon- Fic. 43. A, normal example of Cadla palustris. B, etiolated example of Calla palastris. gated beyond the normal. No other differences of importance could be discovered. Camassia sp. Bulbs of a Quamas?a (Camassia) placed in the dark room in mid- winter soon began a slow growth, the bud pushing up to a length of 2cm. before opening. The sheathing scale had a length of about 3 cm. 88 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. and the leaves developed to the normal length. The inflorescence remained in the form of a slender bud with a scape about 3 cm. long. The outer leaf was attached to a precision auxanometer in such manner that the nutations of the tip were prevented and a complete continuous record for the entire period of growth was obtained, during a period of about fifty days. A study of this curve fails to reveal any regular rhythmic action. Elongation varied from the average rate Fic. 44. Precision auxanometer used in measuring growth of leaf of Quamasza The instrument is shown with the lever attached to a leaf of Lyacznthus, and is adjusted to magnify the elongation forty-five times. (For full description of construction and use see MacDougal’s Practical Text Book of Plant Physiology, pp. 291, 292. 1901.) above and below it at times, but such fluctuations were doubtless due in part to the application of water to the cultures which was done at various times of the day, whenever necessary. The temperature was constant to within 3° C. as described above. (See Fig. 45.) Canna (cultivated). Rootstocks of Canna placed in the dark room soon began to send up a succession of leaves, which reached a maximum length of 45 cm. and which had a lamina more attenuated than the normal, being about 40 cm. long, and only 8 cm. in width. Such alterations from 2 ee * MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 89 6PM.12M.64.M.12M.6PM.12M.6 A.M.12M.6PM.12M6AM.12M6PM. 12M.6A.M.12M.6PM. 12M6AM.12M 6PM.12M.6.AM.12M.6PM.12M.6 AM.12M.6PM.12M6AM.12M6PM. 12M.6A4M.12M.6PM. 12M6AM.12M Fic. 45. Curve of growth of leaf of Quamasza. Plotted from data obtained by precision auxanometer. go MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. ea Me Fic. 46. Etiolated culture of Canna. MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. gI the normal were accompanied by excessive growth of the epidermal cells, and by the formation of stomata apparently normal, and open when examined in water. \L Guttation from the mar- | ee Meme gins and apex of the etio- Sr lated leaves was very marked. After four or ae a, % five months’ continuous ee |. leaf production the root- yy stocks perished. 6S aay Oris, Castanea dentata (Marsh) : Borkh. ge Sale A number of chestnuts were placed in moist soil in the dark room and con- ( trol house October Io, Ig0I, and began germi- L\ nation about fifty days SS later. The stems had wy reached a length of 10 to oem. On january I, ri C 1902. After a length of 25 cm. had been reached So the terminal buds _ per- NS i ~KA ished, and branches from B the first or second bud be- Fic. 47. Epidermis of laminae of Canna. A, ; normal. J, etiolated. low took up active growth, sending up stems which had reached a length of 15 cm. by April 4, moo2.. (See Fig. 48.) The basal portion of the shoot below the point of insertion of the cotyledons showed a diameter of 6 mm. and the main stem about half that amount. The entire main stem and the basal portion of the branch in the illustrated specimen had assumed a brownish hue in consequence of the changes in the cortex and epidermis replacing the normal formation of bark. The leaves were all bract-like and showed two stipular appendages of nearly equal size, all of much the same character as those borne on the first three normal inter- nodes. It is quite significant that this etiolated seedling showed noth- g2 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. ing but the earlier reduced and primitive leaf forms, and about the same number of internodes as the normal seedling. Normal seedlings comparable to the above were of a height of about 25 cm. above the point of insertion of the cotyledons. The basal portion of the stem had a thickness of 3 mm. and the shoot above the cotyledons had a diameter of 2 mm. and tapered gradually toward Fic. 48. Castanea dentata. A, etiolated. B, normal plantlet. the apex by reason of the greater amount of secondary thickening in the older regions. The formation of bark was well advanced and numerous lenticels were present. The normal seedlings were fur- nished with three leaves of approximate adult form and size on the terminal portion of the stem, while on the internodes immediately below were four leaves of a length not greater than one sixth of the adult with the dentation indistinct or entirely lacking. - > > MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 93 The terminal portion of the etiolated stem showed a ring of pro- toxylem with an indistinct cambium region, which shaded grad- ually into the bast fibers external to it. The bast fibers were dis- tinguishable chiefly by their position, the walls being but little heavier than those of the cortical cells. The thick layer of cortex was composed of elements, the radial diameter of which was greater than that of the tangential. The epider- mis was composed of elements with walls but little heavier than those of the cortex. One or two subepidermal layers of the lat- ter were slightly thickened, however. A few stomatal organs with widely open aper- _tures were found, which would represent the beginning stage of lenticels. The cross section of the lower portion of the etiolated stem above the point of insertion of the cotyledons showed an increase of the pith, the formation of a thin wood ring, and the absence of secondary tissues. The cam- bium layer had taken on distinctness in 4) enidermis. B, callapetas places, anda layer of phellogen was visible layer in cortex. C, phellogen. j@atie medio-cortex. The bast fiber cells 2 bard bast. 4, cambium. showed about half the normal thickening. grees The normal stem shows an outer layer of phellogen bounded internally by a cylinder of collenchymatous tissue immediately inter- nal to which the cortical cells contain chlorophyl. A region of cortical cells shows the same indications of collapse as in the etiolated stem, but the formation of a dividing layer in the medio-cortex is not present in the normal stem. Fic.49. Partial cross-section of etiolated stem of Castanea. Cicuta maculata L. Clusters of dormant roots were brought into the dark room in the first week in February, 1901, and the stems began growth within a few days, reaching maturity in about four weeks. The stems devel- oped four or five compressed internodes, from each of which a single leaf arose. The leaves were held nearly erect and the petioles were two or three times as long as the normal. The branches of the petiole in the hypopodial region were only slightly and irregularly developed, the laminar tissues remaining in very rudimentary form 94 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. in closely rolled clumps. The leaves soon perished, and growth ceased. The rootstocks remained alive however and might have been capable of another effort under proper cultural conditions. Fic. 50. Etiolated cultures of Czcuta maculata. The above reactions were practically duplicated in tests with Thaspium trifoliatum grown in small dark chambers at the Uni- versity of Minnesota in 1898 and 1899, and all umbelliferous species behave in this manner so far as my observations extend. Claytonia Virginica L. Tubers of Claytonza placed in the dark room in April, at a time when natural growth of the buds was taking place, did not show MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 95 more than a third of the normal size of the stems, although the tubers still contained a comparatively enormous amount of reserve food. The flower buds remained unopened and the leaves perished quickly. It is quite probable that the limited action shown by this species was due tothe temperature, which was much higher than that encountered in the open air during its period of blooming. The plant would need the capacity of elongation to free itself from the layers of leaves which accumulate to some depth in its habitats. Cocos nucifera L.'” A number of cocoanuts in the husk, freshly arrived from Jamaica, placed in moist soil in December, 1899, soon germinated, and were Fic. 51. Cocos nucifera. Shoot of normal plantlet. placed in the dark room in February, 1900. Leaves were formed from the plantlets which differed from the normal chiefly in a slight 132 See Kirkwood and Gies. Chemical Studies of the Cocoanut and its Changes During Germination. Bull. Torr. Club 29: 321-359. 1902. 96 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. FIG. 52. Cocos nucifera. Etiolated shoot of plantlet after 15 months’ confinement ni dark room. attenuation of the broad laminar portion. A year later, after con- tinuous growth in the interval, the fourth pair of leaves had arrived at maturity in the darkness. A specimen examined on March 6 had absorbed all of the endosperm from the apical end of the fruit, but a great amount of food was still present as a layer increasing in thickness toward the opposite end, where it had been decreased but slightly from its original thick- ness. The absorbing organ com- pletely filled the central cavity, and its rough rugose outer coat was Closely pressed against the re- maining layer of endosperm. A neck or cylindrical body a centi- meter in thickness connected the absorbing organ with the young plantlet. The roots were furnished with numerous lenticels. Numer- ous stomata, open when examined in water, were found on the leaves in the epidermis of the lower side. The upper, inner, side of the leaf seemed to be free from transpiring organs of any kind. Chlorophyl was developed very quickly under the influence of illumination of a gas jet of six candle power at a distance of three meters. A second specimen examined on May 22, 1901, had developed the sixth pair of leaves, a sparse root system, the main root being about 3 cm. in diameter at base, and had not used more than half of MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 97 the food stored in the endosperm, during the period of 15 months in which it had lived saprophytically on the stored food in the fruit. During my absence in the summer of rgor all of the specimens perished. In this as well as in other seedlings the power of ex- tended existence by means of the food stored in the seed is seen. Coix Lachryma-Jobi L. Seeds of Cozx placed in the soil in November, 1899, germinated in the following March and at the end of April had attained a height of 25 cm., showing one basal leaf untolded, and another still in the rolled form. The internodes were about 5 cm. long with sheathing petioles of the same length. The blades had a length of 8—10 cm., and were a centimeter wide at the greatest extension. Normal control examples were 15 cm. in height and the sheathing bases of the leaves about 3.5 cm. in length. The blades were 1.2 cm. wide and 8 cm. long. The lowest internode was about 5 cm. in length, and the one above it 1 cm. It is thus to be seen that the stems are excessively elongated and the leaves also, the latter being but little narrower than the normal. Colocasia sp. Corms of a cultivated Co/ocas¢a were placed in the dark room, in February, 1900, and developed leaves with petioles a meter or more in length, with the laminae only partly unrolled and held ina horizontal position, after the usual habit of the caladiums. The lami- nae attained a length of 10-20 cm. Second and third leaves were produced in quick succession and then the corms were allowed to go into a condition of rest through the summer. Upon the application of water to the cultures in September, 1900, the formation of leaves recommenced. The slight exposures to light in the examinations with a paraffine candle were sufficient to induce the construction of chlorophyl, in this as well as in caladiums and cultivated callas. (See page 86.) The leaves were found to be proheliotropic to such feeble illuminations, and apogeotropic. Guttation was very marked, the exudations issuing from the apices, margins and injured portions of the leaves. Cornus alternifolia L. f. Vigorous shrubs of Cornus 3 meters in height were taken from the soil about December 1, 1901, and after a period in a cool cham- 98 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. ber were placed in the control and dark chambers in the middle of December. ‘The first activity was observed in the specimens placed in the dark chamber on January 18, 1902, at which time a number of buds midway on the branches and on the middle portion of the stem began to elongate. Later all buds on the main axis and branches in the upper portion of the shoot perished and only those from the basal portion survived. These, however, showed a vigor- ous growth. It was found that the upper part of the stems of all of the plants had died as a result of the transplanting. It is noteworthy that the awakening buds were all infra-axillary. On April 6 some of the young etiolated branches had attained a length of 18-20 cm., at which time a photograph was taken from which the accompanying drawing was made. A few branches measured twice this length on June 17, 1902. The etiolated branches assumed an atti- tude very nearly vertical, in consequence of which some of them were appressed to the stem. No branching occurred except in one or two instances. In such the up- permost pair as well as the terminal bud would elongate approximately equally. The leaves on etiolated branches attained a length of nearly a centimeter, but remained small and bract-like, although giving some imitation of the adult form. The hairs so noticeable in the young normal stems and leaves were present even on the older por- Fic. 53. Cornus alterni. tions of etiolated stems and were very folia. Normal branch. abundant on the younger portions. These hairs consisted of a short upright stalk bearing a slender ovoid capitate cell with its long axis parallel to the surface. The branches retained their colorless aspect for some time, and showed a slight tinge of brown in June, five months after their appearance. The cross-section of the apical internode of the etiolated stem showed the pith in the process of enlargement, a thin cylinder of wood cells with an indistinct cambium layer. The bast fibers formed an incomplete circle of spindle-form cells with but little thicken- MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 99 ing. The cortex was composed of the customary thin-walled cells, which with the pith contained some starch, and was furnished with intercellular spaces. The epidermal cells were slightly, thickened as also one or two layers of hypodermal tissue. Some widely open stomata were present. ey Fic. 54. Cornus alternifolia. Base of young tree with spreading normal branches and upright etiolated branches. In the older internodes the pith had attained twice the original diameter, the wood ring had increased by continuous and uniform external additions, and some thickening had ensued in the bast fibers. The number of these elements had not increased, and the walls were pushed inwardly in some instances as if the cells had collapsed. No indications of collapse were to be seen in the outer layers of cortex, or in any way comparable to that seen in Castanea, a fact which is correlated with the shorter period of duration of Cornus. The formation of a distinct phellogen in the epidermal region had 100 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. reached an advanced stage, and was followed by some discoloration of the epidermis. Normal, stems of the same age showed no indications of the formation of phellogen. The cortical cells were smaller than in the etiolated with the tangential greater than the radial diameter. The bast cells were much like those of the etiolated stem. A region immediately underneath the epidermis contained much chlorophyl, which also extended down into the pith through the rays. No marked differences in the trichomes could be found. Cyclamen sp. Corms of Cyclamen purchased from a dealer were placed in moist soil in the dark room in January, 1900. ‘The growth of the leaves soon began, and elongated petioles were formed, which were soon Fic. 55. Cyclamen. A, normal epidermis. B, etiolated epidermis. C, etiolated hairs, from the petiole. JD, normal hairs from petiole. Terminal portion of petiole with etiolated lamina. MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. IOI prostrate with the apical, terminal portion apogeotropic, and bearing the small undeveloped laminae with the upper (inner) surfaces ap- pressed. The petioles and laminae were purplish in color, and the epidermis bore short hairs filled with a reddish cell sap. The etio- lated hairs were slightly smaller than the normal. The epidermal cells were excessively elongated, being four or five times as long as the normal, and the stomata were larger and apparently functional. The production of leaves continued more or less irregularly dur- ing a period of 18 months, and then the activity slowed down, and the corms went into a state of rest from which it was impossible to rouse them, although still sound and healthy. In no instance were the flower stalks developed. Cypripedium montanum Dougl. Dormant specimens of Cyprzpedium were placed in the dark chamber in January, 1900, and began growth a month later. Two months later a young flower bud was pushed out from among the etiolated leaves, but did not open or attain normal size. Fic. 56. A, epidermis from normal leaf of Cypripedium montanum. B, glandular hair from surface of normal leaf. C, epidermis of etiolated leaf. D, glandular hair from etiolated leaf. The main stem attained a length of only 2 cm., which is only a fraction of that of the normal. The excessively elongated leaves 102 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. were 15 cm. in length, and 2.5 cm. wide, while the normal leaves are 8 by 3.2 cm. Epidermal cells from the lower surfaces of the etiolated leaves measured 32 by 4 while those of the normal were only 15 by to. Etiolated leaves bore glandular hairs only, the pointed trichomes being absent. The shaft of the glandular hairs in the normal, con- sists of two cells with an average total length of 50 and diameter of 4, while in the etiolated the shaft was composed of four cells of an average total length of 110 with a diameter of 12. The apical gland measured 22 by 19.5 in the etiolated, and 16 by 13 in the normal. From the above facts it is to be seen that the growth of CyZrz- pedium in darkness is characterized by a non-development of the pointed hairs on the leaves, and the excessive development of the glandular trichomes. The first result is in accord with Schober’s re- sults, but no reason is at hand to account for the excessive enlargement of the glands and the multiplication of the cells in the stalk, unless these organs might be considered as aids to transpiration. The stomata of the leaves were of normal size, but of slightly attenuated outline, being apparently functionally normal. The laminae maintained an erect position, and were more or less’ rolled during all of the period of their existence, embracing about a month. . Delphinium exaltatum Ait. A number of rootstocks of Delphinium exaltatum were potted and brought into the dark room on January 18, 1900, and began to grow at once. The main stem attained a length of 8 cm. as against the normal of 4 cm. and the total height-was 28 cm. while normal plants under similar conditions were only 15 cm. high. The etio- lated petioles reached a length of 10 to 30 cm. while the normal measured only 4 to 6, thus showing the most excessive elongations in the petioles. The petioles assumed a negatively geotropic posi- tion with the laminae pendent by means of a curvature at the extreme tip of the petiole. The actual rate of growth was about twice that of the normal, during a period of ten days kept under observa- tion. An etiolated specimen was cut off and the base of the shoot thrust into water in a calibrated measure, through a cork which was smeared with vaseline to prevent evaporation from the water surface. The total volume of the exposed stem was 5 c.c. and MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 103 included 6 etiolated leaves. 1 c.c. of water was taken up in 24 hours in the dark room at a temperature of 16-18° C. A shoot of a normal plant with seven leaves, the whole having a volume of 2 | c.c. used 2 C.c., or its own volume of water in 24 hours at a temper- , ie | ature of 18 to 20° C. in diffuse . daylight. (See Fig. 57.) Equisetum arvense L. A number of bulb-bearing un- derground stems of Lg¢setum ar- vense were placed in a dark room in January, 1900, and a month ’ 7 HT] if Auli Mt Bh ee Sl DNA t ineiiity i) Fic. 57. Etiotated shoot of Delphinium exaltatum. later two sporophytes and a number of vegetative shoots were to be seen. The latter developed only a small number of branches to a length equal and greater than the normal, the remainder attaining a length of a centimeter or two, and the whole shoot showed some attenuation. In only two instances out of 40 under ob- servation did these branches give rise to branches of the second order. The vege- tative shoots perished within sixty days, a Pe which may have been due to defective Bimetiolated shoot. cultural conditions. (See Fig. 58.) it A few spore-bearing stalks or sporophytes developed to a height of a few centimeters, and the spores appeared fairly normal in structure, showing a green coloring matter, but the sporangia did not open and the spores soon perished. 104 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. : ‘ t <= — Erythronium Hartwegi S. Wats. Numbers of bulbs of Zyrythrontum Hartwegz obtained from dealers were placed in the dark chamber in the spring of 1901, and a single leaf 12 to 15 cm. long was sent up from every one. The ; leaf, as well as most of the bulbs, soon perished, however, probably due to imperfect cultural conditions. Falcata comosa (L.) Kuntze. Tubers of Falcata comosa were placed in the dark chamber in the spring of 1899, and rapidly developed stems. A comparison with control examples showed that the lowest internode of the normal stem was 7 cm. in length and that a runner was sent out from this inter- =a Gy wD SES a os PaO ee eeers SSeS : C DAR SS (BOCES sass eee PY AY OY ae EISELE TPS Come B TA KO FOS FY 3» 45.andas cm., while in the etiolated all of the internodes above the basal one MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 105 described above, had a length of 7 and8 cm. _ It is thus to be seen that etiolation phenomena are shown by this, as well as by all of the other vines examined in the course of the experiments. Furthermore it was found that in no instance did these vines exhibit a tendency to twine about supports as in the normal. Fic. 60. Partial cross section of etiolated stem of Falcata comosa. 8o. Descrip- tion as in Fig. 60. The leaves remained as very small rudiments. Etiolated stems were thicker than the normal by reason of the excessive development of the cortex and pith. The epidermal cells of etiolated plants were larger than the normal in all dimensions. The sclerenchyma showed less thickening, as also the bast fibers, and less sieve tissue was differ- entiated than in the normal. The xylem was also less developed than in the normal. Fagus Americana Sweet. Trees of Fagus Americana 3 meters in height were placed in the control house about December 1, 1901, having been taken from the soil and placed in large pots. About half of the buds were removed from all of the plants. A young plant 25 cm. in height which had been in the greenhouse three years was also placed in the dark 106 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. chamber. No action of any kind was shown as late as June 23d although the temperature was probably suitable for this species. Similar results were obtained by Jost with Fagus. (See p. 26.) Filix fragilis (L.) Underw. Rhizomes taken from the soil at New Canaan, Conn., on Novem- ber 28, 1900, soon showed activity and developed fronds with mid- ribs 25 cm. long with 5 pairsof pinnae. The pinnules were unfolded, being about 4cm. long. The lower pairs were opposite in the usual manner, but the upper pinnules were variously alternated. The entire frond was deeply tinged with chlorophyl. The rootstocks were intact after this growth, and could doubtless send up other fronds after a resting season. Galium circaezans Michx. Rootstocks of Galium circaezans placed in the dark room in January, 1900, developed stems which were 30 cm. long with the 1G. 61. Normal leaf of Galéum circaezans. Fic. 62. Etiolated leaf of Ga- lium circaezans. ongest internode measuring 7 cm. on March 22. The leaves were partially rolled on the long axis, ovate, and with an obtuse apex. MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 107 The middle nerve only was apparent. Motile stomata were present which were open when examined in water. The stems were about 2 mm. in diameter and were circular in cross section, the angles of the normal stem being entirely lacking. Glandular hairs and functional stomata were also present. The epidermis was composed of cells of rounded outlines in cross section, and the collenchyma usually pres- ent in the angles was entirely absent. The etiolated cortex was ex- tremely thin-walled, and showed intercellular spaces. The stele re- mained in an embryonic condition. The vessels of the xylem and Fic. 63. Galium circaezans. A, transverse section of etiolated lamina. B, epi- dermis of etiolated leaf. C, epidermis of normal leaf. protoxylem were barely distinguishable, and groups of sieve tissue might be seen. The epidermal cells of the etiolated stem were scarcely more elongated than the normal, but are wider in surface view. The angle of the stem in the normal bears a duct furnished with glands of the usual stature. The stomata were closely crowded together as if the entire number had been formed in the earlier states of development and were not separated by the normal development of the epidermis, which did not take place. Anthocyan was pres- ent in the leaf, and masses of a yellowish substance in the paren- chyma cells of the laminae, and also in the etiolated shoot. The epi- 108 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. B, epidermis of Fic. 64. Galium circaezans. A, epidermis of normal stem. etiolated stem. ™ 20. enconceres® fare {4 e FR ATEN ia Fic. 65. Partial cross section of normal stem of Galéum circaezans. A, epi- dermis. 8B, cortex containing chlorophyl. C, sieve tissue. D, xylem. £, pith. MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 109 dermal cells of the leaf were naturally smaller in the etiolated organs and more regular in outline, while the palisade tissue, and spongy parenchyma are not differentiated. Fic. 66. Partial cross section of etiolated stem of Galium circaezans. Descrip- tion same as in Fig. 65, except that the cortex contains no chlorophyl. Gasteria disticha Haw. A single specimen brought into the dark room in September, 1900, soon began growth. The young leaves, the apices of which were barely exposed, were carried into an erect position instead of being brought to the horizontal as in the normal. A small offset with thin linear or lanceolate leaves was developed from the basal inter- node, reaching a length of several centimeters on May 20. (See Fig. 67.) This branch perished during the summer. Similar elongation, and erection of propagative branches was to be noted in Sanseveria. The main stem was greatly elongated, the internodes attaining a length IIo MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. of 3 or 4 cm. and were partly exposed instead of being entirely sheathed by the leaf bases as in the normal. A single slender inflorescence axis was developed from the axis of the first leaf reach- ing a length of 4 cm. and then underwent atrophy. The normal leaf of this species is roughly rectangular in cross-section, while the etiolated was double convex. The rugose formations of the normal leaf were lacking in the etiolated, except at the margins of Fic. 67. Gasterta disticha. A, plant after six months in dark chamber, show- ing two leaves formed in light, and two partially developed in light which completed their growth in darkness, also inflorescence, stalks and small runner or offset. the lower etiolated leaves; those found later were entirely smooth. Etiolated leaves were only half the length of the normal, a fourth of their width, and a third or fourth of their thickness. The chlorophyl of the older leaves was retained with no apparent alteration, and a slight tinge of green was noticeable in etiolated leaves due to the occasional exposure to the light used for inspection. he gin td ete GM See 2b ae CL MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. Lie Fifteen months after the culture began, the leaves, which had reached full development before confinement in darkness, had perished and the leaves formed partially in light and partially in darkness had begun to die at the tips. (See Fig. 69.) The upper internodes showed a successive increase in the length of the inter- nodes, and the leaves were held at various irregular angles. Such | Fic. 68. Gasteria disticha. A, partial transverse section of normal leaf. JB, par- tial transverse section of etiolated leaf. C, surface view of normal epidermis of leaf. D, surface view of etiolated epidermis. positions were partly due to the rupture of the stems near the nodes and also to the sheathing leaf-bases. The structural alterations in etiolated leaves were very marked. The epidermal cells of the normal leaf were irregular polygons in surface view, in which but little difference might be seen in the vari- ous diameters. These cells underwent great axial elongation in etio- lated organs, and the outer cutinized layer was notably lacking. The guard cells of the normal stomata are extended outwardly making I1I2 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. an elevation on the surface of the leaf by a single thickening of the outer cutinized layer. Such thickening was wholly lacking in the etiolated leaf, and the guard cells are slightly sunken below the sur- face. The guard cells do not undego full differentiation, and the supporting cells were smaller than in the normal, being functionally Fic. 69. Gasteria disticha. Same plant as in Fig. 67, 14 months after confine- ment in dark room. The leaves formed in light have perished and the younger etio- lated leaves are held in various aberrant positions due to ruptures in the stem. active however, as attested by the long endurance of the etiolated leaves. The parenchyma cells of the normal leaf are richly loaded with starch and chlorophyl, which were entirely lacking in the etiolated organs, the plastids present being much smaller than the normal. The growth of the etiolated specimen continued until Feb- ruary, 1902, at which time it was damaged in handling and per- ished. MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. I13 Gleditsia triacanthos L. Seeds placed in a dark chamber in October, 1900, did not ger- minate until March, after which growth proceeded very slowly. The cotyledons were carried aloft attaining a total length of 15 mm., and were ovate with an auriculate base. The upper, inner surfaces were closely appressed. The cotyledons endured for about 60 days in the dark chamber, when they were thrown off, and the first node of the stem attained a length of 8 mm. bearing a pair of appressed leaves, which did not unfold, but in which the pinnae were distinctly visible. The hypocotyledonary stem attained a length of 18 cm., which is about one and a half times the length of the normal. The root system formed in the dark was very sparse, being made up of a tap root with a very few branches. The lower surfaces of the cotyledons were furnished with stomata, the guard cells of which were loaded with starch, and which were closed when examined in water, being apparently not functional. The seedling perished after the above development had been accomplished. Hemerocallis sp. Bulbs of Hemerocallis placed in the dark room in ec spring after activity had begun in the open, showed an active development which resulted in the formation of leaves 11.5 cm. long. The upper or inner surfaces remained closelya ppressed, and the entire leaf was colored a pale yellow. The flower stalks or inflorescence gave no indications of activity. Hicoria sp. A number of nuts from an unknown species of hickory were placed in moist soil in March, 1900, and germinated in May of the same year. The stems had reached a height of 40 cm. to 60 cm. in June and were then checked by the high summer temperature, the terminal buds being destroyed. In November of the same year a renewed growth ensued after the summer resting period, and one more of the original lot of nuts germinated. The apical buds of the older plants being dead the lateral buds nearest awoke, and the branches formed from them assumed the upright positions of the main stems. Some etiolated specimens removed to the illuminated room developed leaves resembling the customary forms in normal cultures. Growth and development of the shoots continued until March, 1901, thus showing that the seedlings were capable of an 114 MEMOIRS OF THE NEW | : | YORK BOTANICAL GARDEN. existence of nearly a year in darkness at the expense of the food stored in the nut. Hicoria minima (Marsh) Britton. Nuts of Wicoria minima were placed in moist soil in the ‘control chamber, and dark room on October 16, t901. Three of those in the dark room had germinated and sent up shoots, one of which had reached a length of I2 cm. on January 4, 1902. None of those in the control chamber in illumi- nation had shown activity at this time. On Aigmiyae five plants were to be seen in the illuminated chamber with stems 5 to 8 cm. in length and bearing a num- ber of reduced bract-like leaves and two, trifoliate, or simple laminae. At this time the etiolated specimens had attained a length of 25 cm., in some instances bearing a single straight up- right stem with the terminal bud still active. The leaves were simple and bract-like, — soon falling off. The lower third of the stem had begun to show a dark brown color Fic. 70. Hicoriamimima. Eti- olated shoot and terminal portion of normal shoot MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. II5 indicative of the earlier, or initial stages of formation of periderm. On June 17 one stem had attained a height of 36 cm. the longest internode measuring 8 cm. The normal stems of the age of the etiolated showed a brown color at the base due to the death of the epidermal cells. Five or six layers of cork had been formed underneath, and the thick-walled cortex contained much chlorophyl, especially in the outer layers. Crystals were numerously distributed throughout this tissue. A heavy cambium layer was present, and the incomplete ring of bast consisted of cells which had undergone extreme thickening. All _ of the parenchymatous cells were heavily loaded with starch. A cross sectien of the basal portion of the etiolated stem that had begun to turn brown showed the epidermal system in a fairly normal condition with the walls white and translucent. The usual forma- tion of cork in the hypodermal region was lacking, but a median region in the cortex had begun to collapse, the walls assuming a brownish hue giving the external color to the stem. The entire cor- tical region had thinner walls than in the normal and both starch and crystals were noticeably less abundant than in the normal. In this as well as in Cornus and Quercus, the lack of cork formation in the hypodermal region was accompanied by the development of a phel- logen immediately external to the cylinder of bast cells, some- times in immediate contact with the collapsed layer: the bast fibers were nearly normal in stature so far as might be seen in cross sec- tion. A distinct layer of primary cambium could not always be made out, and the walls of the wood cells were not so heavy as in the normal. The above collapse of the median region of the cortex was accompanied, or followed, by the shrinkage of the basal portion of the stem in such a manner that it had a smaller diameter than the terminal portion, a phenomenon also seen in Quercus. Hicoria ovata -(Mill) Britton. Nuts of Aicorza ovata placed in the soil in the control chamber, and the dark room on October 16, 1901, had begun to germinate on January 4, 1902. On April 16, one young plant with two primitive leaves was seen in the control chamber, the stem being about 8 cm. long above the place of insertion of the cotyledons. The lower part of this stem bore a few bract-like leaves. Two seedlings were found in the dark room. One had sent up a main stem about 25 116 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. cm. in height, when the terminal bud perished. A lateral bud then devel- oped an erect branch which extended the total height of the shoot about 30 cm. above the “sor: The terminal bud of this branch also perished and the growth of other lat- eral buds had begun. | The behavior of the | cortical and epidermal tis- sues was much the same as in AY. minima. ‘The median collapsing layer of cortex turned brown- ish-yellow, and with the disintegrating epidermal cells gave the ‘stem a brownish-black hue. The bast fibers were fewer in number, and but little thickened in any instance. Hyacinthus sp. (grape hyacinth). Leaves of awakening bulbs attained a length of 25 cm.in darkness, which ae were crescentic in cross : Bil section, and yellowish, or 4 ~~ perhaps slightly greenish. | ee at the tips. The presence i of some chlorophy] was to be detected in many plants, the leaves of which were Fic. 71. Wicorta ovata. Etio- lated plantlet, and terminal por- tion of normal shoot. MEMOIRS OF THE NEW YORK BOTANICAL formed in the buds of the bulbs or corms. The flower buds retained their dormant condition for atime, then perished. The widths of the nor- mal and etiolated leaves were found to be about equal, but the etiolated leaf was a half longer than the normal green one. When etiolated leaves were brought into light no further increase could be detected either in width or length. A slight flat- tening of the partially rolled or curved leaves ensued, however. Hyacinthus sp. flyacinthus sp. developed leaves 30 cm. in length, which were rolled in tube form, and were II and 12 cm. in width when flattened out for measurement. Secondary leaves from lateral scales of the bulb attained half this length and retained the cylindrical form. No develop- ment of the inflorescence could be seen. Hydrastis Canadensis L. Rootstocks of MWydrastis Canadensis placed in the dark room in January began growth a month later. Sterile stalks bearing only leaves reached a height of 30 cm’. with a diameter about equal, or in some instances exceeding the normal. The petiole at first showed an elbow immediately below the lamina, but which disap- peared on maturity, and the lobes of the lamina were appressed with the upper surfaces together and directed upward. The stems bearing both ieaves and flowers showed a much greater elon- gation, but their length bore about the same proportion to the normal. The curvature of the petiole at first enclosed or shielded the peduncle and pendulous flower bud, thus presenting an elbow of stem as it pushed upward. Finally, however, the petiole became erect, as well as the peduncle which was formerly protected by it. Fic. 72. Aydrastis. Etiolated stem. GARDEN. Y 2 | 117 Starch was lacking from the etiolated petioles except in the guard cells of the stomata. The fibrovascular tissues were fairly normal in their general development and structure, and the stems were approx- imately of the same degree of rigidity as the normal. The epidermal cells of the etiolated stems were slightly elongated. The hairs borne on etiolated stems were not more than one fourth of the length of the normal. Similar differences are to be found on the leaves. The stomata of both the laminae and the stems were slightly open when examined in water and appeared to be functional. No rhythm in growth could be detected from an examination of the aux- Fic. 73. Hydrast’s. Normal anometric measurements. (See Fig. 74.) leaf. 10mm 9 4 6 8 10 12 2 4 (6S A.M. P.M. 2 A 6 .8 10 12 2. -4 0 e A,M P.M 10mm 2 4 6 8 10° "1a 4. 6 8 A.M. P.M. Fic. 74. Curve of growth of stem of fydrastis during three days in dark room at a temperature constant between 22 and 24°C. MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. T1g Hypopitys Hypopitys (L.) Small. Clumps of Hyfopitys which were breaking through the soil near the Marine laboratory at Cold Spring Harbor, Long Island, in 1899 were covered in such manner as to exclude light. No appreciable difference in the stature or appearance of these plants and others in the light could be detected. This test was repeated at Woods Holl, Mass.,in the same year, and also at Priest River, Idaho, in the following year with the same result. It is also notable that {this plant does not usually exhibit phototropic curvatures, although as may be seen by reference to the historical sketch, many fungi are capable of both etiolative and phototropic reactions. WP J i Fic. 75. Etiolated stems arising from tubercle of sweet potato. I20 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. Ipomcea Batatas Poir. Tubercles of the sweet potato placed in moist soil in the dark room in November began to produce stems in January, and sent out a succession of these organs, which were apogeotropic, but soon became decumbent with the terminal portions curved upward. The apical buds soon perished, and the lateral growing points began activity. The leaves developed petioles a half or two thirds of the normal length, with the laminae folded with the ventral surfaces together. The laminae did not attain a superficial area of more than a tenth of the normal. The leaves were crowded together on the basal portion of the stem, being not more than 1 or 2 cm. apart on a section about 20 cm. long, in normal plants. Above this the leaves are more scattered on a portion of the stem in which twining usually takes place. This terminal twining portion was not developed in the etiolated plants. (See Fig. 75.) No important differ- ences could be detected between the structure of normal and etiolated yas stems... The leaves f 0) quickly perished and () dropped off, leaving a yas: J distinct protuberance at the point of connection with the stem. (Fig. 75:) The tubercles per- ished after the first eti- olated growth, and the plant does ,not seem adapted to making a second effort in dark- ness. Iris sp. Shortly after root- stocks were placed in ; the dark room the buds Fic. 76. Etiolated specimen of /rzs, and epidermis began activity, and a of etiolated leaf. succession of leaves was “i Ne MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 121 formed, which were slightly in excess of the normal size. The epi- dermis was elongated beyond the measurements of the normal, and the leaves did not survive long. The stomata appeared to be functional. 4 4 Fic. 77. Normal flowering shoot of Lys¢machia terrestris, and also shoot grown in diffuse light with branches replaced by bulbils. 122 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. Fic. 78. Leafy shoot of Lysimachia terrestris grown in diffuse daylight. Etiolated shoot of Lysi- machia terrestris with apical portion of same enlarged. MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 123 A second series of cultures with a species native to eastern America in March in the dark chamber showed a development of two leaves with a length of 23 and 25 cm. which were free only a few centimeters at the tip. The slightest exposure to the light used in examination was sufficient to stimulate the production of chloro- phyl. Lysimachia terrestris (L.) B.S.P. Lysimachia terrestris consists of a branching rhizome with aérial leafy stems which may bear flowers, or the numerous branches may be converted into, or remain in the form of, bulbils as the author has discovered in some previous investigations. When such rhizomes Rae =ee INS ox(5 OFS \) ) eS = ste sy) — 7 J o' Fic. 79. Lysimachia terrcstris. Partial transverse section of normal stem. 4, air-spaces in cortex; JB, xylem; C, bast fibers; D, glandular ducts; £, sieve tissue. are placed in the dark room, slender etiolated stems without branches or bulbils are produced, with internodes of a length of I to 5 cm., while in the normal stem the length of the internodes varies from 5 cm. to 3 cm., the longest being found in the middle of the stem below the flower-bearing branches. The total length of the etiolated stem was slightly greater than that of the normal flowering shoot, 124 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. which continues to elongate during the greater part of its existence in the open. The opposite leaves on the etiolated stems remained ina rudimentary form and were upright, being closely appressed against the stem. The leaves do not attain a length greater than 5 mm. and a width of 1.5 mm., dying away on the lower internodes as the stems Fic. $0. _Lystmachia terrestris. Partial transverse section of bulbil. RAE ez Fic. 92. Osmunda cinnamomea. Transverse section of portion of normal stelar region. A, endodermis (phloeoterma); G, specialized group of pericyclic cells con- taining tannin; B, EZ, sieve tubes; C, D, metaxylem; F, pericycle and tannin cells in this tissue. 136 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. ternal sieve tubes were larger than in the normal and with lighter or thinner walls. The endodermis internal to the sieve cells just mentioned was less heavily thickened than in the normal, and was not to be separated from the pericycle bounded by it. ra PT AR ae ‘Oa YY LY, (A ee Lk SRLS Ye e o A A a Once es eS = L = Se = 2 SPP aD a ww pps e@ etd H Ee) aT 58) ({ TEAK SEIT \ at CU SS \ es sete. (Y Gs. o% ae suuates peer mK HO Og SS scat er X) 5 SL, PS iS an) Ue] F IG. 93. Osmunda cinnamomea. Transverse section of portion of etiolated stelar . Te€gion correspondent to that shown in Fig. 92. Description as in Fig. 92. MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 137 Oxalis lasiandra Zucc. Bulbs of Oxalis /astandra placed in the dark chamber at various. times were compared with cultures in very diffuse light, and in day- light. The first activity was shown in the development of leaves with elongated petioles and some offsets. The roots did not break out un- A B Fic. 94. Oxalis lasiandra. Transverse sections of leaf. A, normal; B, etiolated. til later. The length of the petioles was as much as I1 or 12 times that of the normal in some examples, while in others it might not reach more than double the length of the normal. In one series of Fic. 95. Oxalis lasiandra. Surface view of epidermis of leaf. A, normal; B, etiolated. tests the average length of normal petioles was 20.87 cm., in diffuse light 36.9 cm., and in darkness 47.1. The thickness in normal and 138 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. etiolated specimens was about the same, but those in diffuse light were much heavier, probably in response to the mechanical stimulus of the weight of the leaflets. The laminae remained in the folded condi- tion in which they emerged from the bud, in the etiolated examples, and attained only about one fifth of the volume of normal examples. Fic. 96. Ovxalzs lasiandra. Surface view of epidermis of petiole, A, etiolated; B, normal. The epidermal cells of the etiolated petioles had an average meas- urement of 127.4 as compared with the normal of 129.1, and a width of 4.91 as compared with the normal at 6.14. The number of sto- mata included in a microscopic field from the etiolated specimen at MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 139 one time was on an average 1.4 and in the normal specimen 2.2, the etiolated measuring 6.82 by 9.56, while the normal measured 9.6 by 4.12, showing that while the size of the etiolated epidermal elements was smaller than in the normal, the number of epidermal cells had increased to meet the excessive elongation of the petiole, but this multiplication has not been followed entirely by the stomata, although some increase has been made. The cortical cells of the petioles gave measurements comparable to those of the epidermis, being 163.45 by 29.5, while the normal were 168.75 by 43.75, showing here also a multiplication of ele- ments. The bast cells in the etiolated were 10.9 by 9.35, while the normal were 11.05 by 9.19, showing a diminution in length, but a slight increase in thickness. The walls are all thinner and only traces of lignification were found in the xylem. The stomata on the leaflets measure 5 by 5.13 in the etiolated and 6.88 by 9.1 in the normal, showing an average of 6 in the field in the etiolated, and 8.6 in the normal. A number of pre-stomatal ele- ments were to be seen in the etiolated laminae, which never under- went the final stages of development in darkness. The hairs on the etiolated leaves measure 281.25 by 5.05 in the etiolated and 128.125 by 4.95 in the normal, thus exhibiting excessive elongation, and but little increase in diameter. The marginal epi- dermal cells of the leaf measured 6.64 by 5.92 in the etiolated speci- men and 25.3 by 8.35 inthe normal. The epidermis of the upper surface measured 5.51 by 4.13 by 4.26 in the etiolated leaflet and 30.96 by 20.8 by 15.95 in the normal. Epidermal cells from the lower surfaces measured 5 by 3.97 by 4.95 in the etiolated and 29.28 by 20.4 by 9.2 in the normal, from which it is to be seen that an increase in the actual number of cells follows etiolation in the leaflets, as well as in the petioles. Differentiation into palisade and spongy parenchyma did not ensue in the etiolated leaflet. The following determinations of ash, dry matter and water in Oxalis lasiandra were made: I. Norma LEAVES INCLUDING PETIOLE. Weight of fresh material 3.13 grams. 66 dry 66 =2 19 66 He ash 6 .O2I 66 Percentage of water 93: 66 dried matter 7.00 140 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. Percentage of ash in fresh material 66 66 dried 6 ¢ 6% Tee) Il. ErioLaTEp LEAveEs INCLUDING PETIOLE. Weight of fresh material UC dried oe 66 ash 66 Percentage of water se dried matter 6 ash in fresh material 66 66 dried 66 -434 gram. -O19 ts -003, ws 95-62 4.38 .69 15-78 V. Leaves Grown IN DiFFusE LIGHT. Weight of fresh material ue dried oe 66 ash 66 Percentage of water in fresh material 6 dried matter Be ash in fresh material 6 66 dried 66 VI. Norma BuLss. Weight of bulbs bearing leaves, fresh “6 dried material ee ash Percentage of water sc dried matter 6 ash in fresh material 66 66 dried 66 Weight of resting bulbs se dried matter u ash Percentage of water ee dried matter és ash in fresh material 66 66 dried 66 VIL. Eri0Latep BurEs. Weight of bulbs bearing etiolated leaves ue dried matter ge ash Percentage of water a dried matter 1.358 grams. .058 - -003, s Oo-1a 4-27 ~221 Sy -599 gram. e127 rites sOOG)3 siya" 79-65 20.35 1.001 4.724 2.685 grams. 1.252 zi .020 sie 53°30 46.63 745 1-597 1.394 grams. -591 ce 0068 | oe 56lre 43-87 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. I4I Percentage of ash in fresh material -446 es ‘¢ dried material [02 VIII. Buss in Dirruse Licur. Weight of bulbs bearing leaves, grown in diffuse light 1.88 grams. Weight of dried material 2066) 8 66 ash O14 ¢ Percentage of water 64.58 6 dried matter 35-42 6 ash in fresh material 744 66 ‘¢ dried 6 21O2 Ill. Errotatep LEAvES AND BuLBs. Weight of etiolated leaves 2.571 grams. 66 6c =LOO)) sc 66 6 -0O5 66 Percentage of water 96.08 ae dried matter 3.92 me ash in fresh material -194 66 66 dried 66 =e 6 water in bulbs bearing etiolated leaves 64.94 Percentage of dried matter 35-06 ee ash in fresh material .634 ks > Sdricd Oo Ley IV. Eriotatep L&Eavss. Weight of leaves, etiolated 1.904 grams. -t dried material 1679), « ae ash “O05 mie Percentage of water 95-85 ee dried matter 4.15 as ash in fresh material 202 es ‘¢ ~=6dried material 6.33 Oxalis violacea L. Etiolated leaves of Oxalis violacea developed petioles 6 to 20cm. in length*which were about .75 mm. in diameter at base and 1 to 1.25 mm. in diameter at upper end. The relations between the dimensions of epidermal cells of normal and etiolated petioles were 142 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. the same as in O. Jastandra. Stomata were present, some of them functional, in the etiolated examples, and the guard cells were always. filled with starch. The epidermal and hypodermal layers as well as. the cortex did not differ greatly from the normal except that the ele- Fic. 97. Oxalis violacea. Etiolated leaf Fic. 98. Oxalis violacea. Transverse after a few days’ illumination. section of stelar region of normal petiole. ments of the cortex had a greater radial measurement than in the normal. ‘The three bundles in the petiole were separated by two or three layers of parenchyma in the etiolated, and by but one in the: LUD CO 22288 ant ces BRITS Fic. 99. Oxalis violacea. Transverse section of etiolated petiole. normal. On the other hand the larger vessels were separated from each other by one or more layers of parenchyma in the etiolated while they appeared in contact in the normal. The sieve tissue seemed more irregularly developed in the etiolated. The laminae MEMOIRS OF THE NEW YORK BOTANICAL GARDEN, 143 of the leaflets remained folded together, and were thickly furnished with hairs. A large quantity of a reddish coloring matter was noted. The bulbs were healthy and small; new ones were formed in both species of Oxal’s examined. After the Production of the first lot of etiolated leaves, growth was confined to the development of runners or offsets. Pastinaca sativa L. Parsnips were placed in the dark chamber in January, Ig9g01, and sent up leaves which had reached full size on April 11, 1901. The petiole and its main branches in the leaf showed excessive elonga- tion. The petiole measured 25 cm. from the stem to the first pair of branches, 6 cm. between the first and second pair of branches of —S.. —— he Sa = S/AIOUEY TT Ui Fa On T Ne oot iy ; paky ne | : Tigge l it l AWAt in eg t ifs L uw ’ Don 1 LPH i a, ] ay WY ie Mal HT WHE, Fic. 100. Etiolated culture of Past¢naca sativa. the petiole, and 3 cm. between the second and third pairs. The distance between the third and fourth pairs amounted to about a centimeter, and the terminal branches were irregularly arranged. The laminae were extremely small and were of a deeper yellow than most etiolated organs. It was found that the size of a leaflet, or the length of the petioles might be increased beyond the average of etiolated organs, by cutting away concurrent organs which would compete for the food supply. The laminae were furnished with many perfect stomata, but no starch 144 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. was seen here, or in any other part of the leaf. The leaves began to perish within a fortnight after maturity, and the rootstock died also. J Peltandra Virginica (L.) Kunth. Corms which showed signs of activity in April were brought into the dark chamber. A month later the petioles had reached a height of 25 to 30 cm. and the Jamina were unrolled but variously in- clined to the vertical. The laminae reached a length of 14 to 16 cm. and a width of 4 to 6 cm. or about half the maximum dimensions. The petioles were more slen- i der than the normal. The lower surfaces of the leaves showed a large number of open stomata which remained open when exam- ined in water, the guard cells be- ing filled with starch. This sub- stance was also abundant in the re- gion contiguous to the nerves. The structure of the leaves was fairly approximate to that of the normal. The upper surfaces presented a number of stomata, but like the normal were not so numerous as on the lower. But little differ- ; ence between the structure of the etiolated and normal petioles could be found, except perhaps in the size of the parenchymatous cells, which were smaller. Similar re- 9% Fic. 101. Peltandra Virginica. Etio- lated culture. MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 145 © sai Fic. 102. Peltandra Virginica. Etiolated culture shown in Fig. 101, after ten days’ exposure to illumination. 146 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. —\_ 2 ey Fic. 103. Peltandra Virginica. A, epidermis from ventral surface of normal leaf. £, epidermis from ventral (inner) surface of etiolated leaf. >< 250. Fic. 104. Peltandra Virginica. .A, epidermis from dorsal surface of lamina, normal. #, epidermis from dorsal (outer) surface of etiolated lamina. >< 300. MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 147 sults were obtained from the study of a number of plants at differ- ent times. A fully etiolated specimen of Peltandra which was brought into diffuse daylight, showed some marked changes as the result of Fic. 105. Peltandra Virginica. A, epidermis from normal petiole. B, epidermis from etiolated petiole. illumination, among which were to be noted the assumption of the horizontal position of the laminae, and the unequal development of the basal lobes which ensued under such conditions. Peltandra is a bog plant, or rooting aquatic, according to circum- stances. Phaseolus sp. (cultivated). Numbers of seedlings of Phaseolus were etiolated with the in- variable result that the first internode attained a length about three times the normal, when proper cultural conditions were furnished. The first pair of leaves developed petioles over a centimeter in length, and laminae of equal length. The entire shoot of the seedlings attained an extreme length of 30 cm., the terminal portion above the : , H 148 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. single pair of leaves being about 6 cm. long, with recurved apex. The stalks were generally more or less compressed and flattened. In other tests the terminal portions of large plants were conducted into small dark chambers to secure ‘‘ partial” etiolations. Branches treated in this manner developed flowers which were fairly normal, except that they were blanched. The essential organs were perfect, and fertilization en- sued, pods and seeds being formed. The latter were apparently perfect, but no germination tests were successful. The leaves were entirely devoid of chlorophyl, but the leaflets were held in various posi- tions with the upper surfaces concave, and did not exhibit the nyctitropic movements, so far as my ob- servations went, although particular attention was not paid to this point. It is to be seen that the effects of ‘‘ partial etiola- tion” differ most widely from those in which the en- tire plant is deprived of light. In partial etiolations Fic. 106. Etio- FIG. 107. Terminal portion of shoot. The branch A, has been enclosed in! lated seedling of small dark chamber and bears leaves, flowers and young pods formed unde Phaseolus. these conditions. MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 149 it is difficult to furnish absolute security against admission of light, and the darkened portion is probably influenced by the illuminated regions near it. Phytolacca decandra L. A number of strong roots of pokeweed were taken from the soil in a resting condition in November and placed in pots a the control house, and dark room immediately. Growth began about a month later. The shoots pro- duced in the dark chamber elongated much more rapidly than those under normal illu- mination and had attained a length of 22 cm. on January 22, 1902. Shortly afterward these shoots perished and others sprang up from the crown, which likewise made only a limited growth. This process was repeated, and on April 27 four etiolated shoots were to be seen with others beginning to develop. On July 6th the stems had reached a length of 42 cm., with leaves 45 cm. long. The tuber- ous underground storage organ remained intact and seemed sound and healthy. The diameter of etiolated stems did not exceed Ir mm., which is much less than the normal. The cross section was ovoid in outline although lacking the small irregular- ities of that of the normal stem. The etio- lated leaves consisted of a small slightly elongated petiole curved upward froma horizontal position with a much reduced lam- ina. The entire leaf was a rich yellow color. The pith showed the transverse splittings of the normal stem in the basal portion, but in the terminal portion a long continuous cavity occupied the center of the stem. The epidermis was not excessively elongated and had comparatively thin walls. The prestomatal cells were to be seen richly loaded with granular matter and plastids and in some instances the first division had taken place. The collen- chyma was fairly well developed in the angular portions of the stem occupying about six or seven layers, in some instances and but two Fic. 108. Etiolated stem of Phytolacca decandra. I50 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. or three in other places. The cortex was composed of extremely thin walled elements with some intercellular spaces. The protoxylem was fairly normal but the woody tissue was very imperfectly developed, while the formation of the secon- dary wood ring and xylem had only progressed so far as to show Fic. 109. Phytolacca decandra. Structure of etiolated stem. A, epidermis; B, collenchyma; C, cortex; D, bast fibers; /, location of secondary cambium; /, cam- bium; G,xylem; H, surface view of epidermis, showing one prestomatal cell. groups of elements with denser contents in the positions of the vessels, and the presence of a layer of cambiform calls external see 3 to them. Numbers of elongated lenticellular ridges appeared on the basal portion of the stem in the region from which the leaves had fallen. The comparatively brief duration of the shoot was coupled with the non-formation of stomata on the stem. Podophyllum peltatum L. Rootstocks of Podophyllum were brought into the dark room at various times and the leaves and flowers allowed to develop. Petioles showed an elongation about 80 per cent. in excess of the normal and the epidermal elements were correspondently elongated. The lobes of the centrally peltate leaves were about one third the length of the normal, and were folded with the under surfaces together, the whole etiolated laminae having the form of a partially opened umbrella. Stems bearing both leaves and flowers reached a length about double the normal in darkness, and the flowers were fairly normal in structure opening partially. The lack of functional ma- — turity of the stomata was accompanied by a brief duration of the leaves and stalks, and the etiolated organs soon perished, resting MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. I51I buds being formed on the rootstocks which could not be awakened in the dark room. Fic. 110. Podophyllum peltatum. A, stem bearing flowers and two leaves; 8, peltate leaf. Normal. Polystichum acrostichoides (Michx.) Schott. Clumps of Polystichum acrostichoides were brought in from the open, and forced in the dark room in February at the New York Botanical Garden. The fronds soon developed long upright stipes along which were borne the pinnae tightly rolled in clumps. Much of the excessive elongation took place in the basal portion, which at- tained three times its normal length. The sporogenous tissues at the I52 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. Fic. 111. Podophyllum peltatum. A, B, stems bearing flower and two leaves; C, peltate leaf. Etiolated. MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 153 eo ete AP Pe , OT gp a f nee OPA ey he T H, | Hh nl Fic. 112. Polystichum acrostichoides. Normal. % } *h é @ Y Cag 4 ? re q 1 a Q \ — ee AN Mal tH FAN iM Ih J a ra Hit : f a ” me A A, etiolated culture. B, same after two Fic. 113. Polystichum acrostichoides. weeks’ exposure to illumination. 154 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. apical portion of the frond remained inactive. The other pinnae were curled with the lower outer surfaces outward. Etiolated forms placed in light first assumed a position by which the terminal portion was carried more or less horizontal, and some expansion of the pinnae ensued, which however did not reach normal stature. : Populus Simonii Carr. Some small trees of Populus Simoni? 3 and 4 meters in height were brought into a cool house on December 1, 1901. Two weeks later several were removed to the control house and one to the dark room. Within a fortnight both showed signs of activity. The branches showed a tendency to de- velop the buds near the apex and base most strongly, the terminal bud making the greatest amount of elongation in both the normal and etiolated examples. A month after the beginning of growth the branches arising from the basal and middle regions of a normal branch showed 1-3 internodes with a tctal length of not more than 4 cm. The etiolated buds developed branches three or four times as long in similar regions, and the terminal ; etiolated buds developed branches with a length of 30 cm. or more, in some instances. The normal term- j inal bud sent out branches not more than 10 cm. in. length, and with four internodes. The etiolated terminal S branches showed eight internodes | — which were sometimes as much as Zi 50 per cent. longer than the nor- mal. Similar relations were found Fic. 114. Leafy branch of Pofulus between the normal and etiolated Sree; Morea branches over the entire plant. ee ew E ie 5” 155 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. The etiolated leaves were small, recurved with a petiolar portion a few millimeters in length, and the entire organ not more than 15 Etiolated branch of Populus Szmoniz. DTS \s Fic. » wast 1) yr os The upper surfaces of the atrophied laminae were in- The leaves were distinctly yellow while the stems were 9 S Oo is 8 ES ao ry} HW jb canes ¥ apace A, Partial transverse section of normal branch. Fic. 116. Populus Simonit. F, wood. E, cambium. D, bast fibers. G, cortex. B, collenchyma. epidermis. The stipules were very nearly normal size in A most striking phenomenon consisted in the almost a pure white. etiolated examples. 156 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. superior thickness of the etiolated stems, which showed a diameter nearly 50 per cent. greater than the normal. This increase in size was accompanied by a loss of the winged angles characteristic of the branches during the first season of normal growth. le o> NI Py >. } D Ry yer LATA Se () O < x ee. AE prone oh L/) NM I i i a LN) ye Fic. 117. Partial transverse sections of etiolated branch of Populus Simonit. A, epidermis. £, subepidermal region, showing earlier stages of a lenticel. C, cortex. D, bast fibers. A, cambium. (See Fig. 116.) The epidermal and subepidermal layers lack the thickness of wall of the normal, and the hairs were scarcely half the usual size. Lenticels were to be seen in the earlier stages of formation on normal twigs, which were wholly lacking in the etiolated. The greater diameter of etiolated branches was due to the excessive de- velopment of the cortex, which was composed of larger elements with smaller intercellular spaces. The bast and sieve tissue as well as the cambium and xylem all showed arrested, or retarded develop- ment. . MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 157 Potentilla sp. Resting plants of a native species were brought in from the meadows in the autumn, and after several months in a cool dry room were placed in the dark chamber. The petioles developed a length of 14 cm., the laminar portion of the leaf being represented by a compact bud-like formation about 5 mm. long and 2 mm. thick. No other organs were visible and the limited activity of the leaves was coupled with a small supply of reserve material in the rootstocks. Pteris longifolia L. Clumps of rootstocks of Pter/s were placed in the dark room early in March, 1gor. In the succeeding cultural observations the ® i ews. \) \ \ NN bs at} fay iW Fic. 118. Culture of Prerds Jongifolia with etiolated and normal leaves. fronds already formed persisted and appeared normal, the chlorophyl retaining its usual aspect. Young fronds sent up in the dark 158 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. attained a length of 30 to4o cm. The excessive elongation was shared by the entiré stipe and midrib. The distance between the pinnae is 2 cm. normally, but in the etiolated it was 3 cm. The pinnae reached a length of about a centimeter, were curved and had the margins inrolled, and were about 3 or 4 mm. wide at the truncate cordate base. The entire frond contained chlorophyl, and the hairs were somewhat longer than in the normal examples. The number of hairs was about the same as in the normal, and the greater elongation of the frond made them appear more sparing, being dis- tributed over a greater amount of space. Normal pinnae are about 6 to 8 cm. long and 1 cm. wide at the base. The transverse diam- eter of the basal portion of the etiolated stipes was about 2 mm. while that of the normal was 1 to 1.25. The increase was due chiefly to the increase in size of the fundamental parenchyma, epidermal and hypodermal tissues. Similar increase was also to be seen in the vessels. The frond actually unrolled its entire length in some speci- mens, the terminal lamina being borne on a stalk a centimeter long, and not attaining a length of a twentieth of the normal. Quamasia. See Camassia. Quercus palustris DuRoi. Acorns of the swamp, or pin oak, of the crop of 1901 were placed in the soil in the control chamber and in the dark room in November, IQ0I, germinating in about four months. The normal seedlings had developed stems 2.5 to 3.5 mm. in diameter at base and about 25 to 35 cm. in length on July 6, 1902. The lower internodes varied greatly in length from a few millimeters to 5 cm. in one instance, and bore only small bract-like leaves. The terminal portions of the largest plantlet, about 3 cm. in length, bore 13 leaves, the uppermost of which approximated the adult type in size and form. The oldest etiolated specimen had attained a length of 25 cm.. and the internodes were more uniformly elongated to lengths of 1.5 to 3-5 cm., the length increasing as the tip of the stem was ap- proached. A younger plantlet that had made more rapid growth had developed one internode 6 cm. long. The exaggeration in length of etiolated shoots of this species is clearly a matter of exces- sive elongation of the basal internodes, since the total number was MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 159 much less than in the normal. The etiolated leaves were small and bract-like and the terminal portion of the stem was recurved, bearing the compact bud in a position favorable to piercing overlying layers of soilor humus. (See Fig. 119.) The etiolated stems were not beyond 2 mm. in diameter in any instance, which was less than the normal. The reddish tinge of the etiolated stems was but little altered even in the oldest portions. The walls of the epidermal and underlying layers were slightly yellow, and indications of collapse were visible. No noticeable multiplica- tion of the cortical elements could be detected. The formation of a phellogen in the medio-cortex had begun. The bast fibers were less thickened than in the normal, and were widely separated by the primary rays. ‘The sieve cells were not distinguishable and cambium could be made out only in places. The xylem components were less highly developed than in the normal, and the walls of the vessels were comparatively thin. (Figs. 122-126.) The basal portion of the oldest normal plantlets showed a dis- tinct phellogen immediately underneath the epidermis and a loosely arranged cortex, in which no phellogen could befound. The cortex was richly loaded with chlorophyl. Numerous crystals in globular clusters were to be found which seemed wholly lacking from the etiolated. Quercus rubra L. Acorns of Quercus rubra were placed in the soil in November, 1901, in the dark room, and control chamber and germinated within a period of six months. Normal plantlets on June 23, 1902, were from 8 to 15 cm. in height, with the internodes from 2 to 5 cm. long, inclusive of those of the terminal portion of the stem. The crowding of the leaves, owing to shortness of the uppermost internodes as in 2. palus- tris, was therefore lacking, but in several instances contiguous inter- nodes were shortened in such manner as make it appear that the leaves were opposite or in whorls of three. The basal portions of normal stems were about 4 mm. in diameter, tapering to half that amount at the tip. A few of the basal leaves were bract-like, but most of them were of the normal adult type, which, with the stems, were more or less pubescent. Etiolated plants of the same age as those described above had attained a height of 30 to 35 cm., consisting of 10 to 12 internodes 160 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. and a sparse root-system. The maximum length of the internodes was about 5 cm., and the shorter ones were perhaps half that length, the whole stem showing a some- what uniform excessive elongation of these organs, and in no instance were the leaves opposite or whorled. The leaves borne on the 8 or 10 lower internodes were small and bract-like, but those borne on the upper part of the shoot were of a general form similar to the normal, being about I cm. in length, the petiole occu- pying half that length. These organs were recurved with the apex of the lamina in contact with the base of the petiole. The curved and pointed hairs were longer than in the normal. The basal portion of the etiolated plants had under- gone discoloration of the epi- dermal and_ subepidermal tissues over a portion about <=) 8 cm. in length. The maxi- ii] mum diameter of the etio- lated stem was hardly great- er than that of the normal Fic. 119. A, Quercus rubra. Etiolated seed- in any instance. As in the see a amaans oh com sil adherent. 2, other oaks examined, layer i of phellogen were formed in the medio-cortex, while the external cortex and epidermis collapsed. The inner cortex was somewhat more compactly arranged than in MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 161 the normal, and the lack of development of the stelar components was fairly similar to that described in other oaks. The normal stem has a subepidermal phellogen and a loosely arranged cortex con- taining much chlorophyl. : Quercus sp. Germinating acorns of an undetermined species of oak were placed in the dark room in March, 1900. On May 19, cultures in the dark room showed stems with 30 internodes and a height of 75 cm., while the control plants in a room in which the tem- perature was somewhat more fluctuating and the air was dryer, : gd: ITT Fic. 120. Quercus sp. Transverse section of normal petiole. showed 8 internodes and a length of 22 cm. Etiolated leaves about _ cm. in length which was twice that of the stipules, were to be seen, with a small lamina, which was not entirely unfolded. The base of the etiolated stem had blackened and discolored up to a dis- tance of 20 cm. from the base. A branch arose from the axil of the sixth leaf, and reached a length of 20 cm., bearing only scale-like leaves. The maximum length was shown by the fourth internode 162 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. from the base and by the basal portion of the branch. The greatest length of an internode was 5 cm. as contrasted with 4 cm. in the normal. It isthus to be seen that the excessive elongation of the stem Fic. 121. Quercus sp. Transverse section of etiolated petiole. was due chiefly to the multiplication and development of the inter- nodes. The stipules were excessively lengthened and were persistent. FiG. 122. Quercus sp. Partial transverse section of terminal portion of etiolated stem. £, epidermis. D, collenchyma. C, cortex. The epidermis of the terminal portion of the stem was more or less thickened, and the hypodermal elements were also more col- lenchymatous than is shown by most etiolated forms. No differentia- & nai MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 163 Fic. 123. Quercus sp. Partial transverse section of terminal portion or etiolated stem. J, bast fibers. &,cambium. /, xylem. /, perimedullary layer. mM ep ) iy )) i , A. ) i i " ; ® ist @ ye) a ae Wr d ee a > JU Fic. 124. Quercus sp. Partial transverse section of lower part of stem. I, nor- mal. II, etiolated. 4, epidermis. D, phellogen. C, collenchyma. J, cortex. roan nD er Rice ~ + 2AS Lal = S. wi oy co ele (Sharm et Os a a2 - w Os » Y ee eS) th O45 a) eo U ane won OSs a V ow = 9g a) Oo Oo o Oo QD > Ss 3) x cB) 5 12) ale et oe ag 3 BB —= Ss Oo eeciies pe | “ oO r= A s a, -_ A a4 a ead ae Ss te 2» £0 Waar GY & IY ay fe ek ws ’ fi on Hig. 125% seedlings: fibers. KY attuned Ay + Coa Sesnone aa AA TSK ES Mowe } Zoey aso SO a LTS ES LIST ROK SEES AE On SK 0 VL4 LA YESS ee 1 OL RSE REE sve Sageence neweweetns = (~ _ (eaeeie Uncen Ig recat eo Sh eee sony | SEN REMeHeNe erie SL ° Gam le) Bere eS eeecs Moye ps ecececert vw UO 4 aagtaeé Ol OCs Lo i os © of seedling. A, perimedullary parenchyma. &, woody cylinder. bast fibers. (p. 165.) Fic. 126. Quercus sp. Partial transverse section of lower part of etiolated stem C,cambium. JD, £, inner cortex. 166 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. tion of phellogen was found, although it was marked in the corre- sponding region of normal stems. The cortical cells in the etiolated appear to be smaller than in the normal stem, and more compactly arranged. The bast fibers form a continuous irregular \ circle in the cross section of the normal stem but were still separated by the medullary rays in the etiolated. The more interesting differences of structure were to be found in the lower and older parts of the stem. The epidermis and hypodermal cells inthe etiolated had be- come irregular and were slightly collapsed. A phel- logen had been formed in the medio-cortex, and the cortical cells were somewhat larger than in the normal, and with thinner walls. The difference between ihe bun- dles of bast fibers was still very marked. The sieve : tissues showed a diameter Fic. 127. Quercus sp. Seedling in second about half that of the nor- year. Normal (oblique) and etiolated branches. : mal, and the cambium layer was not so well marked as in the normal. The elements of the xylem were in general larger in all dimensions, but the thickness of the xylem ring was hardly half that of the normal. The walls of all of the tissues in the xylem were thinner. (Figs. 123-126.) The petioles showed corresponding differences in the normal and etiolated. The epidermal tissues were less thickened, and no col- lenchyma was to be seen. The separate bundles of the meristele were in a very rudimentary stage, with the sieve tissue but imper- fectly developed, and the pericycle entirely lacking. The bundles were clearly separated by rays of parenchymatous tissue. (Fig. 121.) A seedling of an unknown Quercus was brought into the dark =? MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 167 eee et I0 12 2 4 6 OSs. oo A.M. P.M. 10mm mero 6 G6 U0" 12 Oe Aw 6B AO 4g A.M. P.M. ee oO 6 68 108 12 Oe A ON BAO. eee OCC SO ID CCU A BO A.M. P.M. 10mm [ee 686Gl6™!CUC8!lCUhL10 C122 DCU AC CGC BO 1D A.M. P.M. Fic. 128. Curve of growth of etiolated petiole of Rewm in dark chamber at tem- peratures 21-23°C. The actual amount of growth during the two hour periods is denoted by half the distance from the base line at a point above the numerals to the wavy line denoting rate of growth. 168 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. room in November, 1901. Two buds near the base of the young inclined stem soon awoke and formed stems 15 and 25 cm. in length. Fic. 129. Etiolated leaf of Rhewm, % actual size. These etiolated stems were twice the thickness of the normal, due to the exaggerateddevelopment ef the cortex ‘and sae internodes were longer than the normal. The leaves did not go beyond the stage described above. (Fig. 127.) Rheum sp. Rootstocks of rhubarb obtained from a dealer were placed in a dark chamber in the early part of March and sent up leaves in which the peti- oles were both thicker and longer than the nor- mal. The branches of the petiole in the laminar portion of the leaf separ- ated but slightly, and in so doing ruptured the in- active lamina in many places, a phenomenon also observed in the re- lated genus /umex. Such etiolated leaves. elongated at a fairly con- stant rate, the minimum being shown about 10 A.M. It could not be as-- certained from the study of the auxanometric data whether this resulted from a true rhythm or — MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 169 whether it was the consequence of application of water about the hour in question, after which elongation increased. (Fig. 128.) The composition of etiolated leaves of rhubarb has been the sub- ject of many studies and tests on the part of practical investigators, and the cultivation of this plant in darkened cellars, and in total dark- ness is an industry followed by many gardeners. This method of cultivation appears to have been hit upon by Knight. A recent manual gives the details of management of these plants in darkness." Rhus sp. (native shrub). A root of /¢hus carried into the dark room in March with a clump of soil adherent had developed a shoot 35 cm. long with seventeen rudimentary leaves by May 1, the lower eight of which had fallen off. The angular outline of the normal stems was preserved, and a number of lenticels were formed near the base of the shoot. The pith was composed of uniformly thin-walled cells with large intercel- lular spaces. A cambium layer could not be made out, but some bundles which from their position must have been of secondary for- mation were to be seen. The cortex was very thin-walled and no thickening of the subepidermal tissues was seen. The epidermis was free from stomata, but bore numerous pointed and glandular hairs. The sections assumed a milky appearance on being placed in water. The leaves attained a total length of over a centimeter and were curved downward. The two basal pairs of pinnae were extended but had a total length of only afew mm. The leaves were densely hairy, showing both forms of trichomes as noted below. No stomata were formed, which is correlated with the brief existence of the shoots which soon die in darkness. Ricinus communis L. Seeds placed in dark chamber germinated and produced hypo- cotyledonary stems 30 cm. in length, which were weakly erect. The cotyledonary stalks were 2 to 3 cm. long. The cotyledons were not ‘freed from the endosperm in any instance, and made no growth, soon falling off, exposing the plumule. The first pair of leaves. attained a length of about 8 mm. If the endosperm were removed the cotyledonary stalks curved downward after the customary move- 1344 Knight, T. A. Ona method of forcing rhubarbin pots. Trans. Hort. Soc. Lond. 3: 154. 1820. Morse, J. E. The New Rhubarb Culture. New York, 1go1. 170 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. ment which brings the cotyledons to a horizontal position in normal plants. In some instances the seedlings continued ex- istence after the endosperm and cotyledons had been discarded altogether. The first internode often assumed a length of 5 cm. and had leaves with laminae a centimeter across, with the petioles re- flexed. Rumex sp. A resting specimen of a AYumex native in the Garden was brought into the dark room December 1, 1901. ‘Two weeks later the development of the leaves began and a succession of these organs were formed during the next four months. During my absence from the Garden during February and March, 1902, no observations were recorded, but 20 of these organs were seen and the plant was still alive and engaged in sending up leaves, on July 23, 1902, making an additional noteworthy example of a plant capable of extended endurance without the activity of the chlorophyl apparatus. The petioles of the etiolated leaves attained a length of 30 to 35 cm. and were flattened on the in- ner, ventral surface. The laminae were represented by thin lamellae of yellowish tissue which extended along the midrib for a distance of 14 to 17 cm. with a width of about a centimeter narrowing toward the base and apex. The petiole appeared to be in a state of elongation throughout its entire length, and the excessive growth of its continuation in the midrib resulted in the rupture of the lamellar struc- tures. In some instances the laminae showed sufficient resistance to set up a marked tension, by ~ which the midrib was held in a curved position some time before giving way. The epidermal cells of the petiole were excessively elongated and some of the normal compound hairs were seen, being also present on the lamina. Perfect and functional Fic. 130. Etiolated leaf of Rumex sp. 3% actual size. MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. L771 stomata were found both on the petiole and laminae. Geotropic curvatures were exhibited by the terminal portions of some of the leaves which had fallen prostate while still growing actively. Salvia sp. Numbers of branches of a cultivated Sa/v/a were thrust into small metal dark chambers during the course of the observations in 1896 and 1897. Such chambers were made as tight as possible by means of packing of cotton wool, but it can not be definitely affirmed that all light was excluded. If the branches had already laid down flower buds, a development would () WN ensue in which the calyx would attain about two thirds of its nor- Fic. 131. Sa/véa sp. Normal flower with mal size, but the corolla, which is extended corolla and etiolated flowers with - corollas atrophied. usually much longer and _ highly colored, failed to emerge from the calyx, and was almost colorless. The stamens and pistils also failed to reach normal stature or to at- tain functional maturity. Sansevieria Guineensis Willd. A specimen was placed in the dark room in September, 1900, and when examined in May, 1gor, nearly all of the mature green leaves originally borne by the plant were still alive and but little changed as to texture or color. Three young leaves which were about 10 to 15 cm. long at the beginning of the etiolation were now twice this length by basal growth, and the additional portion thus formed was a very pale green incolor. One prominent terminal bud had become apogeotropic and formed an upright stem 15 cm. in height with the lower sheathing bracts about 12 mm. in length which is something in excess of the normal. This growth of the upright stalk was continued after a resting period in the summer of 1go1 and in’ January, 1902, seventeen months after the beginning of the test, this stalk was 20 cm. long. May 1, 1902, twenty months after confinement all of the leaves had perished, but the etiolated stalk still continued. The basal inter- nodes had attained a length of 12 to 14 mm., but those nearer the tip 172 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN, a Fic. 132. Sansevieria Suineensis. Culture after confinement in dark room for 20 months MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 173 of the stem which had now reached a length of 35 cm. were not more than 5 to 7 mm.4ong. The stem had fallen prostrate by its own weight, but the terminal portion had curved upward apogeo- tropically. A number of small papillar projections a millimeter in diameter were seen emerging from various parts of the internodes. In some instances the emergences were from nodal areas, while in others a position in the middle of the internodes was occupied. Gen- erally but one of these structures was found on each internode, but in some instances two were found. These emergences were sup- posedly young roots. The terminal half of this upright stem was imbedded in the soil in the propagating house, and developed a new plant, forming an exception to the old statement that etiolated organs could not be used as cuttings. The upright etiolated stem showed two or three layers of epidermal cells with brownish collapsing walls, a fundamental parenchyma of small elements, with some intercellular spaces. The outer fibrovascular bundles were notably reduced in both xylem and phloém as well as in the stereome. Sarracenia purpurea L. Numbers of specimens were grown in the dark chamber in 1898. The leaves were wedge-shaped in transverse sec- tion, and slightly greater in diameter than the normal. The leaves already formed, and which had reached a length of a €xposure to illumination for 18 days. C, etiolated leat. 174 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. few cm. before being placed in the dark chamber formed a small pitchered cavity, and an extension of the flap to a width of 8 or 9 mm. The over-arching lip extended only 2 to 7 mm. beyond the end of the cylindrical portion which would have formed the pitcher in the normal. Leaves which developed from the bud after being placed in dark- ness showed the normal size of cavity, but the lateral flap of the leaf Fic. 134. Epidermal structures of normal leaf of Sarracenia purpurea. A, epi- dermal cell and hair from terminal flap. B, surface view and section of epidermis from “attractive” area. C, epidermis from ‘‘ conducting ” area. D, epidermal cells and hair from ‘‘ detentive ” region. After drawing Wm. B. Stewart. was reduced to a wedge-shaped rudiment, and the arching lip was scarcely apparent. In such instances glands were found over the entire leaf and long, slender hairs were to be seen in the pitchered cav- ity. The diameter of the cavity in the normal pitcher was six to eight times that of the etiolated leaf. The etiolated leaf was twice as long as the normal, and much of the elongation took place in the basal 4 Pia, ays MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 175 portion of the leaf, which was five times the normal. This elongation also extends upward into the basal portion of the cavity of the pitcher which in the region below the detentive hairs was ten times the normal. The region covered by the detentive hairs was 1.4 times that of the normal. Above this the etiolated conductive surfaces was only one eighth of the normal and the attractive honey-bearing region had dis- appeared. The lateral flap of the normal was nine times as long and —<—$_ ——— —— — SS “Sis aaa ine arenas Fic. 135. Epidermal structures of etiolated leaf of Sarracenia purpurea. A, from terminal flap. B, ‘‘ attractive” surface. C, from ‘‘ conducting ” surface. D, from ‘‘ detentive” region. £, inner surface of cavity of ascidium. (After Stewart.) sixteen times as wide as the etiolated. The relative lengths of the various regions are shown in Fig. 136. The epidermal cells of the external surface of the upper part of the leaves ranged from 10 to 22 in length in the normal and from 25 to 63 in the etiolated. The width in the two instances ranged from 7 to 20 in the normal and from 3 to 5 in the etiolated. Not all of the stomata were differentiated. 176 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. The epidermal cells in the lower portion of the cavity which underwent excessive elongation were 1.64 times as long as the normal, but the normal were 1.4 times as wide as the etiolated. A similar re- lation holds in the detentive area where the epidermal cells were 1.29 times the normal in length but the latter are 1.55 times the etiolated cells in width. An increase of the actual number of cells in the etio- lated detentive region was thus demonstrated. In the conducting sur- He Fic. 136. Diagram showing relative development of various regions in normal and etiolated leaves. I, normal. II, etiolated. -A. terminal flap. B, ‘‘ attractive ” surface- C, ‘‘conducting” surface. D, ‘‘ detentive” surface. £, cavity below detentive sur. faces. F, petiole. Drawn by Wm. B. Stewart. face the cells of the epidermis are 1.35 times the length of the etiolated, in the normal and are also 5 times the etiolated in width, showing a decrease in the number of cells. The same is true of the attractive surface in which the normal is more than twice the etiolated in all dimensions. Trichomes of all kinds are both longer and thicker in the normal. *. MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 177 Sarracenia variolaris Michx. Rootstocks of Sarracenia variolaris were placed in the dark room in January, 1900, and etiolated leaves had reached the maximum size [SS Fic. 137. Sarracenta variolaris. A, epidermis from outer surface of normal leaf. B, epidermis from outer surface of etiolated leaf. C, etiolated leaf. 178 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. j in March. These leaves showed torsions of the basal portion, and at- tained a length of 18 to 20 cm., which was not in excess of the normal. The over-arching hood was found in the etiolated leaf as a conical pro- Fic. 138. Etiolated cultures of Saururus cernuus. A, lamina and portion of pet- iole of etiolated leaf. MEMOIRS OF THE NEW YORK BOTANICAL GARDEN, 179 jection I to 2 mm. in length, and generally two gland-like structures were to be seen on the upper edge of the lateral flap. Other rudi- mentary glands were to be found down along the edge of this lateral ex- tension. The utricular cavity was present and extended to a depth of 3to5mm. It was lined with small cells rich in protoplasm which were wholly undifferentiated. ‘The epidermis of the outer surface of the leaf was composed of cells with four walls in surface view, and were also rich in protoplasm. Honey glands were present. The epider- mal glands, as well as the stomata, were fairly normal. No trichomes were present. ‘The pitchered cavity also lacked the hairs and glands of the normal. The leaves endured existence for three months after nearly full size had been reached. (Fig. 137.) When etiolated leaves were placed in light the lateral flap under- went some extension but no great differentiation of the utricular formations ensued. . Saururus cernuus L. Rhizomes placed in dark chamber in May, rgor, soon developed stems with a height of 40 to 54 cm., being composed of 9 or Io inter- _ nodes each 2 to 11 cm. long and showing a diameter at base of stem Fic. 139. Saururus cernuus. Partial transverse sections of etiolated and normal stems. I. Etiolated. II. Normal. A, epidermis. 4, collenchyma. C, cortex. of 1.6 cm. and at apex of .6 m. The petioles attained a length of 5 cm. in some instances, but the sheathing bases did not keep pace 180 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. with the thickening of the stem and they were soon cast off. The laminae were partially unfolded and measured about 5 by 3 cm. A few of the axillary buds showed some development and runners were sent om s= Fic. 140. Epidermis of etiolated petiole of Saururus cernuus. out from the bases of some stems, each bearing several smaller leaves of the above aspect. It is to be noted that this plant roots in mud and may grow in water 60 cm. in depth. (Figs. 138-140.) Sparaxis sp. Plants of Sfaraxds placed in the dark room sent up leaves to a height of 10 to 20 cm. which were strictly erect and closely adher- ent, and soon perished. No flowers were developed. The humidity and temperature was probably too high for this species. Solanum tuberosum L. In tests to determine the length of time this species might endure continued deprivation of illumination it was found that two seasons might be passed without light, smaller tubers being formed on branches. The tubers formed during the second season perished because of unfavorable conditions in the culture room, and it is perhaps possible for this species to endure considerably longer periods without light. A number of tubers were placed in the dark chamber in October, 1900, and by March, 1901, had produced a great number of length- ened club-shaped foreshoots which were 20 to 30 cm. long and 1.5 to 2 cm. in thickness with no geotropic sensibility. These stems were extremely brittle. Branches were curved in various ways and were easily detachable. Typical tubers were formed on the branches from such stems under the surface of soil. This experience was MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 181 repeated in the winter of 1902. Similar shoots 60 cm. long were formed with but few branches. The epidermis formed a few func- tional stomata, and the epidermal cells contained highly granular lining layers of protoplasm. The thickened foreshoots described above grew and remained alive about six months. Taraxacum sp. Rootstocks of dandelion placed in dark chamber showed some attenuation and a full blanching of the leaves. Excessive elongation ensued in the basal portion. Tipularia unifolia (Muhl.) Br. Specimens received from South Carolina and placed in the dark room developed new corms of two internodes each 3-5 cm. long from the apical portion of which leaves 20 cm. in length were sent up. The laminae were rolled in a cylin- drical form, and were wholly free from chlorophyl. The width of the leaves was about that of normal organs. Trillium erythrocarpum Mx. Corms placed in a small dark chamber in 1896 devel- oped stems slightly longer than the normal with the leaves epinastic in such manner as to ) sheathe the flower bud. Itis Fic. 141. Normal and etiolated cultures of to be noted that these tests were 77" ¢”ythrocarpum. imperfect etiolations. The flowers opened slightly, but did not form fruits (Fig. 141). %Batalin, A. Ueber die Wirkung des Lichtes auf das Gewebe einiger mono- und dicotyledonen Pflanzen. Bull. d. 1. Acad. Imp. d. St. Petersbourg, 7:69. 1869. In addition to other papers by Knight (see p. 4) and Véchting (see p. 21), see Véchting, H., Ueber die Keimung der Kartoffelknollen. Bot. Zeitung, 60: 87-114. 1902. 182 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. Trillium erectum L. Plants formed in the dark room in 1896 had the leaves appressed around the base of the peduncle and were smaller. The peduncles Fic. 142. Normal and etiolated cultures of Tr¢lléum erectum. were not so long as in the average. The flower opened in a fairly normal manner, but did not produce fruits in these imperfect etiola- tions. Milla uniflora R. Grah. = 7rctelia uniflora Lindl. Plants were etiolated in March, 1900. The leaves, which are normally twisted and curved, attained a length of two or three times the normal, being 35 to 50 cm. long and 5 to7 mm. in width. Num- bers of leaves from lateral buds attained a length of 10 cm. anda width of 1 to 2 mm. MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 183 The inflorescence axis emerged from the sheathing leaves at a distance of about 8 or 9 cm. from the bulb and was distinctly apoge- otropic with the peduncles attaining a length of 14 to18 cm. THe flower stalks were extremely sensitive to light, soon showing apoge- otropic curvatures. ‘The etiolated flowers were enclosed by two trans- lucent bracts united except at the tip and projecting beyond the flower 5or6mm. These sheathing bracts arose about 5 or 6 mm. from the base of the flower tube. The separate portions of the perianth were about 16 mm. long, ovate and with the adnate stamens apparently perfect. The relative proportions of the stamens and pistils were as inthe normal. (Fig. 144.) Fic. 143. Normal culture of Willa uniflora. The normal leaf of 7rcteléa = Milla is 12 to 15 cm. long and 8 to 10 mm. wide, being perfectly plane in cross section, while the etiolated are crescentic. The flower and its stalk are about 18 em. long and become negatively geotropic after fertilization. The sheathing bract is about 2.5 cm. long, splitting as in etiolated specimens and is dorsiventral. The ovary is about 2 cm. long and the perianth about 3 cm., being variously colored and marked with a purple midrib. The open perianth is wheel-shaped. (See Fig. 143.) 184 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. Fic. 144. Etiolated culture of Milla uniflora. MEMOIRS OF THE NEW YORK BOTANICAL GARDEN, 185 Tulipa patens Agardh. Tulipa patens etiolated in spring of 1900, developed leaves 30 to 60 cm. long with inrolled margins and torsions present but not so marked as in 7. sylvestris. The leaf from the lowest internode 47 cm. above the bulb was about 2 cm. wide at base and sheathed the second and third leaves. Thesecond leaf arose from a node 4.5 cm. above the first and the third arose from a node I cm. above the second. The pedicel of the flower was about 6 to 8 cm. long, the perianth segments were I to 1.2 cm. long and were of a pale yellow. The stamens were of equal length and deep yel- low. The pistil was about 1.4 times the length of the stamens. The pedicels reached a-length of about 2 cm. and the floral organs slightly larger than the normal in some instances, being apparently perfect except for blanching. Tulipa sylvestris L. The leaves were 30-33 cm. long and trailing in etiolated specimens grown in 1900, and marked torsions were exhibited. The margins were tightly inrolled nearly half way to the center, and the entire blade was twisted tightly into a roll in which only the lower, outer surface was visible. The new bulb was formed laterally to the old one in a manner characteristic of the normal, both sending down long offsets. No flowers were developed. Vagnera stellata (L.) Morong. Etiolated specimens of Vagnera stellata -sgegettesabetee grown in the dark chamber in April, 1900, showed a length of stem of about 55 cm. which was equal to that of the normal. The leaves were about 5 cm. long in the etio- Fic. 145. Etiolated culture of Vagunera stellata. lated and 12 to 15 cm. in the normal. The upper part of the stem became horizontal in the normal, but remained upright in the etio- 186 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. lated. The leaves of the etiolated specimen soon perished, but the development of the inflorescence progressed so far that some of the terminal flowers had opened in a manner apparently normal. The rootstock remained sound and healthy. Viola obliqua Hill. Specimens of a violet native to the Garden were taken from the soil in March, 1900. This is an acaulescent species which ordinarily Nae Fic. 146. Viola obligua. A, epidermis of normal petiole. 2B, epidermis from etiolated petiole. C, epidermis from normal lamina. JD, epidermis from etiolated lamina. £, etiolated specimen, sends only its petioles and peduncles above the soil. The petioles of the etiolated specimens attained a length about double that of the MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 187 normal. The petiole at the base of the lamina was curved in such manner that the lamina was held pendant in an inverted position in the earlier stages of growth. With the growth of the petiole, this curve became accentuated until finally the tip of the lamina was projected upward, the petiole having curved through 360°. The epidermal cells of the etiolated petioles measured about 280 by 9g, and of the normal about 65 by 9. The stomata were open and functionally normal. The thickness of etio- lated and normal petioles was about the same. The laminae were rolled with the edges over- lapping. Some of the stomata are functional but the greater number are not differentiated. Viola rostrata Pursh. Specimens of Vzola rostrata were placed in the dark chamber in January, 1900. The shoot reached an extreme length of 18 cm. and the petioles of 6 to 10 cm. The laminae were not unrolled and were held pendant by a curvature of the petiole at the base of the lamina. In transverse section the epidermal cells were seen to be muriform and the mid- dle of the laminae consists of four or five un- differentiated parenchyma cells with some air- spaces. The stomata did not open. The cross section of the petiole showed eight to ten fibrovascular bundles with annular, spiral and scalariform ducts present. The cortex was composed of twenty layers of large cells, equal to about half of the diameter of the pith. Small intercellular spaces were to be seen in the cortex. A subepidermal layer was slightly thickened. The epidermal cells were slightly papillose in places. * No distinct cambium ring was formed. The stipules of etiolated specimens were about 4 by 7 mm., while in the normal they are but 3 by 1.5, thus showing an increase in size in darkness. The normal stem had a cortex about equal to the pith in thick- ness and a heavy pericycle. A cambium layer was present in the Fic. 147. Vztola ros- trata, etiolated shoot. 188 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. normal. The subepidermal cells were well marked and large air spaces were to be seen between them and the epidermis. The development of the xylem scarcely exceeded that of the etiolated. (Fig. 147.) Woodwardia radicans Sm. Rootstocks of Woodwardia placed in the dark room in 1900 show a succession of stalks 25 to 30 cm. long and 3 to 4 mm. thick, bearing a few brownish scales which fell off later. The laminae and its branches remained as tightly rolled cylinders, which showed a distinct tinge of green, but which began to decay with no indications of opening. In its development it agreed fairly well with other Polypodiaceae. The normal specimen has a leaf with a stalk 20 to 25 cm. long and passing into a rachis with a length at least 50 per cent. greater. The pinnae are widely spreading, are 20 to 30 cm. from tip to tip. The etiolated specimens therefore show only a development of the stalk perhaps slightly elongated beyond the normal, with the entire foliaceous portion inactive. ADDITIONAL OBSERVATIONS. Acer rubrum L. A young tree of the red maple was brought into the dark room in November, 1901, and buds began to elongate on the lower part of the main stem early in the following May, followed later by the activity of others over various portions of the main stem and of the branches. The older etiolated stems reached a length of 15 to 65 cm. by July 22, and were about twice the thickness of normal twigs and shoots of the same tree formed during the previous season. Juvenile sprouts from the bases of young trees growing in the open, however, during the early summer, developed stems fairly equal to the etiolated ones, both in length and thickness. The etiolated stems were but weakly erect, soon falling over by their own weight where- upon the apical portions curved upward apogeotropically, giving the stems the appearance of trailing, and reminiscent of Acer cercinatum. The normal branches of the tree in the dark room during the previous season in the open air, and of other trees in the open developed MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 189 about 2 to 5 internodes of a thickness not more than one third of the etiolated, and a total length of not over 5 cm., the maximum length of single internodes being less than 5 cm. Etiolated branches developed 6 to 8 internodes, or about the same as juvenile sprouts, the maximum length of the internodes being about 14 cm., which was double that of the juvenile sprouts. After the above growth had been made in darkness, the terminal buds perished, and activity was generaliy begun by the buds on the basal portion of the etiolated twigs, although some were developed on the terminal portions. It was noticeable that the greater number of buds on etiolated twigs that awakened were exposed to the occasional illumination of the gaslight by the aid of which exami- nations were made. In one instance an etiolated shoot showed a development of all of the main axillary buds on the illuminated side, and none on the other. The etiolated twigs bore pairs of opposite leaves, the petioles of which had a length of about 2.5 to 4 cm., and the small laminae measured 2 by 1.5 cm. being extended, and about one sixth of the normal size. (See Fig. 148.) Fic. 148. Acer rubrum. A, etiolated branch with leaves. B, normal greenleaf. The anatomical changes which may be ascribed to the effects of etiolation in Acer were more nearly parallel to Cornus than to Quercus or Hicoria. The subepidermal layers of cork were present, and the formation of lenticels had begun in the basal internodes of the etiolated stems. Such lenticels were larger and more numerous 190 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. than in the stems of old trees in the open, but bore a general re- semblance in occurrence and form to those on juvenile sprouts. The walls of the epidermal and underlying tissues of etiolated twigs were slightly tinged with brown and the reddish cell contents of the normal epidermis were entirely lacking. The outline of the cross section of the normal twig is distinctly angular while in the juvenile and etiolated stems it was nearly circular. The subepi- dermal corky layers were present in the juvenile, adult and etiolated branches, the underlying cortex being thickened collenchymatously, pitted, and containing chlorophyl] in the two normal forms, while in the etiolated the cortical cells were but slightly thickened, being flattened radially, with some intercellular spaces. The etiolated twigs showed, but a faint development of bast fibers, which with the lack of development of the collenchyma, must account for the mechanical weakness of such stems. The cambium layer is well marked in three kinds of branches, the wood cells and vessels show- ing larger lumina and thinner walls than the normal, although not so large as in the juvenile forms. The same may be said of the pith. The epidermal cells of the normal twigs of juvenile, and adult sprouts and twigs show a length parallel to the long axis of the branch fairly equal to the width, being somewhat irregular in out- line, while in etiolated examples these elements are drawn out into more nearly regular rectangles as seen in surface view, being about six times as long axially as tangentially. The tangential width of the epidermal cells was about the same as in normal adult branches. The dorsal surfaces of the leaves showed stomata which were open when examined in water, and appear to be functionally active. The duration of the leaf did not exceed twenty days. Trees beginning activity in the dark room in May, still bore etiolated shoots in various stages in the following September. Jost cultivated some species of maple in the dark room in the winter of 1891 and 1892, and found that some of the buds of young trees developed into elongated etiolated shoots. The excess of growth in length was not so marked as in Aesculus, however. It was noted that some secondary thickening, or the formation of an additional ring of wood, was seen near the base of the etiolated shoot in the old stem.!° ‘8 Jost, L. Ueber Beziehungen zwischen der Blattentwickelung und der Gefiissbil- dung in der Pflanze. Botan. Zeitung, 51: 108. 1893. MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. Ig! AEsculus Hippocastanum L. Seeds of the horse chestnut placed in the soil germinated in the control chamber, and in the dark room in the following May. Nor- mal seedlings sent up a stem in which only the basal internode de- veloped a length of about 11 cm. and a diameter of about 9 mm. at the base tapering to 4 mm. at the summit. ‘The normal seedling with a shoot consisting of a single internode on July 22, bore a single pair of quinate leaves and a strong terminal bud. The normal internode was somewhat angular in outline and of a deep green color. (See Fig. 149.) On July 22 the single etiolated seedling on hand had developed a stem 50 cm. in length consisting of ten internodes, the terminal one Fic. 149. ALsculus Hippocastanum. Normal seedling. of which had made about half of its probable ultimate growth. The basal internode was 12 cm. in length, and with a diameter of 7 mm., thus "exceeding the normal slightly, both in length and thickness. This,"as well as the other etiolated internodes, was compressed in the plane of the opposite leaves. The leaves were represented by pairs of sessile bracts with broad clasping bases and ciliate margins wholly unlike the foliar organs developed on the seedling. It is to be Ig2 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. noted that the first pair of leaves in the seedling in this plant are truly foliar, and that these bract-like organs resemble nothing more than the cataphyllary leaves of the older stem. It seems probable that these bracts may be considered as the leaf-bases and they per- sist only a short time, being alive only on the second internode from the apex of the stem., Numerous lenticels 1 to 3 mm. in length and half of that in width were to be seen, over the entire etiolated stem. The epidermal cells of the etiolated stem had collapsed in the older portions, and were generally rectangular in surface view, being two or three times as long as broad. In some instances, however, the ends were acutely oblique. The phellogen underneath the epidermis comprised five to seven layers, and the outer cortex seven to nine layers, the latter being composed of elements heavily thickened collenchymatously, and flattened radially. The inner cortex was also similarly compressed, but the walls were not so heavily thickened. The bast fibers were only slightly thickened. Internally to these cells was found a mass of irregular thin-walled elements which shaded gradually into the cambium, which in turn passed gradually into the woody tissue. The vessels and tracheids showed larger lumina than in the normal. The pith was composed of perforate parenchyma richly loaded with starch, and it is to the exaggerated growth of this tissue that the excessive thickness of etiolated stems is to be ascribed. The root system of the etiolated seedling was somewhat sparse, and the cotyledons were turgid and still contained some starch and other food material. The normal stem of seedlings was furnished with a phellogen much like that of the etiolated, but the epidermal layer showed a number of outgrowths in the form of short-pointed hairs, which were not seen in the etiolated. The outer cortex is thickened collenchym- atously, and contained much starch and chlorophyl, while the inner layer was composed of elements with much thinner walls. . The bast fibers were heavily thickened. The formation of some secondary tissue had begun on July 22, and the medullary rays were diverted from the radial position as if torsions had been set up. The outline of the stem was obtusely angular. The root system was more profusely branched than in the etiolated example. A single seedling AZsculus was allowed to germinate in the con- MEMOIRS OF THE NEW YORK BOTANICAL GARDEN, trol chamber in full illumination until the plumule of the young shoot was almost disengaged from be- tween the cotyledons, and the curved portion of the stem already exposed bore a pair of small quinate leaves. The plantlet was then removed to the dark room and allowed to continue growth. Not only did the leaflets of the first pair of foliar organs Continue growth, attaining nearly double the size shown at the time of their removal to the dark room, but all of the leaves borne on the etiolated and erect stem a month later also had five small leaflets which were en- tirely lacking from perfectly etiolated seedlings. It is thus to be seen that the stimulation of light upon the basal portion of the young shoot induced the de- velopment of laminar members on internodes which not only were not exposed directly to the light, but which were not developed until some time later. The evidence afforded by this demonstration also bears most strongly against the acceptance of any etiolation results in which light is excluded from a portion of the plant only. Small trees of this species were cultivated by Bon- nier in a continuous illumination from electric arcs of such intensity that oxygen was given off at one-third the normal rate by aquatic plants. Under such condi- tions the shoots did not attain normal size and elon- gated more slowly than under the usual conditions of alternating daylight and darkness. True foliar leaves were produced which were very green. No differen- tiation of bark or lenticels ensued, and the cortex was thinner than in the normal, as well as the central cylinder. The cortex was differentiated into two zones as it appeared to do under both normal condi- tions and in absolute darkness, in the experiments de- scribed above. The sinuosities of the pericycle were less accentuated. The thickening of the pericycle was less marked, and the woody tissue was less perfectly Fic. 150. ALsculus Hippocastanum. Etiolated] seedling 60 days old. 193 194 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. developed. The greatest difference was to be seen in the secondary wood, which consisted of much smaller elements with thinner walls. The perimedullary layer was perfectly developed and the pith was greater than in the normal. The influence of weak continuous illumination is thus fairly similar to that of darkness, so far as the central cylinder is concerned. The differentiation of the cortical and epidermal systems is carried much farther in the etiolated specimen examined. It is to be recalled however, that Bonnier’ used small trees showing adult stems, while the stem described above is that of the seedling, which in the normal, consisted of the first internode. Apios Apios. (See page 42.) After the first series of observations on Af~zos was made, oppor- tunity was afforded for an examination of the subterranean branches upon which the tubers are formed by the swelling of the apical por- tions of the internodes. ‘The earlier stages of the development of these formations was accompanied by the differentiation of a secon- dary cambium or generative layer in the pericycle, very similar to that exhibited by etiolated stems. The increase in the radial diam- eter of the cortex was not readily noticeable however in the tuber- forming stems. A subepidermal phellogen is formed early in the tuber-forming stem, but this does not take place in the etiolated, or in the normal aérial stem. Etiolated stems were free from trichomes, in contrast with the subterranean tuber-forming internodes, which bore these structures in great number. Fagus Americana Sweet. (See page 105.) Young beech trees from 30 cm. to 3 meters in height were brought into the control chamber and dark room in November, 1901. No activity was shown until July, 1902, when several buds on the smaller plants began to elongate, producing branches, which in some instances reached a length of 3 to 8 cm. by September 1, 1902. Such etiolated branches consisted of 3 to 6 internodes varying in length from 4 to 15 mm. and bore minuté leaves on the basal por- tions and larger foliar organs on the terminal portions. The maxi- mum size of these leaves was 8 cm. in width and 12 cm. in length. The leaves, as well as the stems, were silky-hairy, the trichomes hav- ing much the normal appearance. . ‘87 Bonnier, G. Influence de la lumiére électrique continue sur la forme et la struc- ture des plantes. Rev. Gen. d. Bot. 7: 253, 254. 1895. ee a a MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 195 Buds were formed on the calluses over cut surfaces in a few of these small plants, and these, together with some of the awakening dormant buds, made a growth of a centimeter or less, then went into a resting condition being loosely covered with silky-hairy brown scales (see Fig. 152). The above observations are fairly in accord with those made by Jost * upon Fagus sylvatica (?). Jost found that darkness hindered the development of beech buds, and that when a few buds were exposed to the light by the extrusion of a branch from the dark room, the others in darkness showed greater activity than the buds of plants wholly confined in darkness. The first crop of buds developed in darkness were but 3 cm. in length, and a second series awakening later made a growth of about 8 cm., bearing leaves about 5 cm. long. Jost believed to have demonstrated by his series of ‘‘ par- tial etiolations ” that some substance formed in light is necessary to the growth of buds of the beech. The larger trees used in my own experiments were trimmed by having a few of the larger branches cut away, and the only growth shown by such trees consisted in the formation of buds and branches from the calluses formed over the m@enndss Thebudsinsomeinstances 1%: 151. Fagus sylvatica. A, nor- ed aot elongate Baas nua. centit nal leaf. J&B, etiolated leaf. Drawn to scale. meter before going into a resting condition, while in others branches 18 to 20 cm. long were formed, consisting of 5 or 6 internodes, of a length of 2 to 5 cm. and bore leaves which fell away after attaining a length of about 5 cm. The stems and leaves were silky with appressed hairs. Numerous lenti- cels were formed. Normal stems of trees in the open air made a growth of 6 to 11 cm. in the season of 1902, and about 5 or 6 internodes were formed with lengths varying from 2 to 42 mm. The internodes of the 18Jost, L. Ueber den Einfluss des Lichtes auf das Knospentreiben der Roth- buche. Ber. d. Deut. Bot. Ges. 12: 188. 1894. 196 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. etiolated branches are thus seen to be excessively clon a fact accounting for the superior length of these members. The normal stem of the current season’s growth showed a col- lapsing epidermis, an underlying collenchymatous layer of cortex, and an inner cortex with larger elements and thinner walls. Both regions contained chloroplasts. The bast fibers of the pericyclic region were grouped in such manner as to give the usual crescentic transverse section, being separated by the external continuation of the rays, which also separate the bundles widely. Some reddish coloring matter in the outer layer of the cortex was almost masked by the brownish tinge of the walls of the epidermis. Etiolated stems showed structural divergences of degree only. The phellogen, collenchymatous layer and inner cortex were distinguishable. The cortical cells were furnished with thinner walls and contained so much reddish coloring matter that the etiolated stems had a decided pinkish tinge. The bast fibers, which are grouped in about twenty clusters in the normal, appeared in about forty smaller groups in etiolated stems, the crescentic outline of the trans- verse section appearing more flattened. The cause of this apparent multiplication of the clusters of bast , fibers is not clear. It might be ascribed to the non- Fic.152. Branch development of some of the fibers, thus breaking the of Fagus Ameri- normal clusters into smaller groups, the elements hay- cana, which has ing thinner walls than in the normal. Cambium was been in dark room . - 8 months. A,nor- Present in etiolated stems and the medullary rays were malbudwhichhas Not so wide as in the normal. Less thickening oc- notawakened; 8, curred in all of the woody tissues. Stomata were Nie ienenicae present on the dorsal (lower) surfaces of the etiolated branches. leaves, although nothing but the most minute open- ing could be detected between the guard cells. Bonnier™ cultivated Fagus sylvatica in continuous illumination in the same manner as A Zsculus (see page 191), and found that phellogen was not formed under such treatment. The number of sieve tubes was less than in the normal, and the rows of vessels and tracheids were seen to be more closely crowded together by ¢@he inferior Bonnier, G. Influence de la lumiére électrique continue sur la forme et la struc- ture des plantes. Rey. Gen. d. Bot. 7: 300. 1895. | i ' The internodes of the 2 { oles about 4 or 5 cm. MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 197 development of the medullary and intravascular parenchyma as in etiolated stems of /. Americana. Ibervillea Sonorae Greene. A number of large woody tubers of ‘ guarequi” were collected from the sandy plains around Torres, Sonora, Mexico, in February, 1902. Some were placed in the control house and others in the dark room in May, 1902. Adventitious buds on the upper surfaces of the irregular tubers soon began activity, sending up vines 3 meters in height and climb- ing by means of extra-axillary tendrils after the manner of the Cucurbitaceae. These tendrils were extremely sensitive and reached a length of about 6 cm.- glabrous normal stems were about 6 to 8 cm. in length, and the peti- Etiolated stems did not reach a length in excess of 50 ‘cm., a limited growth perhaps partially due to the high humidity of the dark room. The plant is found to flourish best under the same con- ditions as_ subtropical cacti from the most arid regions of Amer- ica. The internodes of the etiolated stems were fairly normal in length, except the basal ones which were much elongated, but were about double the thick- ness of green stems. Etiolated petioles were about a half longer than the normal. Tendrils were present, but did not attain the Fic. 153. Normal branches of /bervillea Sonorae. o 198 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. normal length, soon becoming curved as in normal mature organs, but did not assume the irregular corkscrew form of these or- gans. Etiolated tendrils were irrita- / ble to contact in the stage when they had reached a maximum size, but the BS resulting curvatures carried the tips ~ Ey eal with continued contact, and in a few | instance these organs succeeded in encircling a support. If the irritable p surface was placed in contact with a support one or two turns would be j made around it, but the free portion did not assume the corkscrew form. If stems which had begun growth in / light were removed to the dark room the first etiolated tendrils developed subsequent to the removal were larger than if the entire growth had taken place in the dark room, affording an- other example of the endurance of the stimulating effects of light in partial etiolations. The excessive thickness of etio- lated stems was found to be due to the greater size, and perhaps some multi- plication, of the parenchymatous ele- ments in the stele and cortex. The tips of the stems as well as the petioles were apogeotropic. Fic. 154. Entire etiolated shoots of Jbervillea Sonorae. B, B, sup- port, clasped by a tendril at A. Lycopodium lucidulum Michx. A number of bulblets of Lycopodium luctdulum in the germinat- ing stage were found near Cold Spring Harbor, L. I., about the middle of July, 1902, and representatives of the various stages of development were preserved, while some in a resting condition were brought in and placed in the dark chamber. These structures are composed of several thickened fleshy leaves, and are formed in the axils of stem leaves, being in fact modified branches, and containing much chlorophyl. About a month after confinement in the dark through only a few degrees, except. ee MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 199 room, the main axes of the gemmae began to elongate, and sent up stems about 15 mm. in height, which were fairly equal to that of nor- mal specimens. The etiolated stems were almost devoid of color, but a faint greenish tinge was noticeable in the leaves. The cells were larger in all measurements and the stelar tissues less per- fectly differentiated. The etiolated stems were slightly thicker than the normal, and bore about five leaves, which were appressed and much narrower and shorter than the normal, being bract-like. The distance be- tween the leaves was greater than usual, correspondent to the internodal elongation Fie. 155. Lycopodium lu- of the higher plants. One or two roots had Fagen aon aaa plaice been formed by some gemmae, and the lat- eee Pa ter has begun to assume a yellowish aspect as if the chlorophyl were breaking up. The growth of the etio- lated plants continued for five weeks from the time of germination. Smilax Beyrichii Kunth. Tubers of S7zz/ax from Florida collected in October, 1901, were placed in the dark room and control chamber in January, 1902, and began growth in May. On October 7, 1902, etiolated stems had been formed that had a length of 80 to 90 cm., consisting of 18 to 20 internodes of a length of 2.5 to 4.5 cm. Normal stems had formed a much larger number of internodes which made up a total length of 2 to 3 meters, the separate internodes measuring about double the etiolated members. Numbers of weak prickles half of the length and thickness of the normal were formed in darkness, in addition to which some papillar projections were formed on the basal etiolated internodes which were doubtless rudimentary roots. Leaves were represented on the etiolated shoots by sheathing bracts something larger than the normal, being over a centimeter in length, and bearing a narrow lanceolate body at the apex a few millimeters in length representing the petiole and lamina. Tapering papillae on either wing of the base near the lamina represented the ten- drils. These organs arose from the extreme margin, and had the appearance both in the etiolated and normal organs of being branches 200 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. : of the hypopodium although designated as not homologous with any part of the leaf by Goebel. B Fic. 156. Smilax Beyrichii. A, normal immature leaf with tendrils, natural ize. B, etiolated leaf, consisting of an exaggerated basal portion, bearing atrophied tendrils, and a rudimentary lamina, X 4. Etiolated stems were thicker than the normal by reason of the in- crease in the size of the cortical cells, which were also furnished with thinner walls, the collenchymatous thickening to be found in the inner portion of this region in green stems being lacking. The numerous fibrovascular bundles were not so strongly developed as in the normal. The newly formed smaller bundles to be seen in the cortex of normal stems were not found in the etiolated stems. 140 Goebel, K. Organographie der Pflanzen. Part II., p. 432. 1898. — GENERAL CONSIDERATIONS. Modes of Influence of Light upon Plants. — The relations in which plants stand to radiant energy are so diverse, and the several effects of light and darkness upon plants so intimately interlock that a brief statement of the currently accepted conclusions upon various phases of the subject will be a necessary preliminary to a critical discussion of the records of researches cited in this memoir, and of the new facts which have been brought out in my own investigations. The term light is used in the present paper to denote waves of radiant energy included in the spectrum between the infra-red rays with a wave length of .760 » and the supra-violet with a wave length of .397 es Sunlight has been found to exert analytic, synthetic, isomerismic, polymerismic and catalytic effects upon the chemical substances which may be isolated from the protoplasm of plants. It is fairly probable however that no such extensive action ensues when the various substances and compounds are bound up in the metabolic system of the living cell. At the present time evidence is at hand to show that certain synthetic effects, such as the union of oxygen with some portions of the protoplasmic substances, may be produced in the organism, and that it is to this cause that the destruction of bacteria in sunlight may be ascribed. It has also been found that light exerts a direct influence upon the enzymes in protoplasm. In the earlier stages of such action the effect of the red, orange and some blue rays seems to increase the amount of enzyme present, and later a disin- tegrating effect was exerted by these rays, the violet and ultra-violet being constant in such analytic or catalytic action. To the violet and blue-violet rays is also to be ascribed the oxidizing action noted above as well as the disintegration of chlorophyl. It is of course entirely probable that the action of light may set up chemical processes in the plant is in a manner entirely stimulative, and independent of any communication or transformation of energy. So far as known facts are concerned, the only method by which light might exert an effect 141 MacDougal. Practical Text-book of Plant Physiology, 110. 1901. 202 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. upon growth would be by the decrease of the enzymes participating in the various stages of the process. That the rapidity of growth becomes less under illumination in many plants is beyond all doubt, but that such effect is due to the direct paratonic action of radiant energy is a matter that will come up for further discussion in this paper.'” The stimulative action of lightin chemical processes is well illustrated in the matter of formation and maintenance of chlorophyl. Protoplasm is capable of constructing this complex and unstable substance in darkness, and of maintaining it in a fairly normal con- dition for periods extending over many months. In many species however, the process of formation is not set up except under the stimulation of light, and the entire spectrum appears to participate in the stimulation. Simultaneously, however, the upper end of the spectrum exerts a disintegrating action, which is prebably a direct chemical effect of the same character as that by which enzymes are broken down. Radiant energy in the form of light being the most important source of energy of plants, it enters into manifold physiological relations with the shoot. The plant has codrdinately a number of capacities for adjustment to various phases, degree of intensity, and angle of incidence of the rays. An added interest is attached to this feature of the subject from the fact that the capacity for these adaptive reactions have been formed to respond to associated characters rather than to the exact portion of the spectrum with which the action of the plant is concerned. ‘Thus the phototropic reactions of plants are induced in greater part by the more refrangible blue violet rays, the resulting movements being for the direct purpose of placing the surfaces of the chlorophyl-bearing organs at a proper angle for the economical and safe reception of the orange red rays. It is true of course that the two kinds of radiations are almost invariably associated so far as the experience of the vegetable world is concerned, but the fact remains that the stimulation in question is one of association. A further ex- ample of such associations in irritability is to be found in the sensi- bility of reproductive organs to light. Seeds and spores are benefited directly in a few instances only, by exposure to light, yet the conditions for the distribution of seeds and spores are more commonly favorable “2? MacDougal. Critical points in the relations of light to plants. A résumé read before the Society of Plant Physiology and Morphology, Baltimore, Dec. 28, 1900. Abstract in Science, 13: 252. IQOT. MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 203 when the reproductive organs are held up in sunlight. Here the phototropic response is made to a stimulus ordinarily associated with a series of complex conditions embracing currents of air, activities of animals useful in dissemination, water, etc., which are actually necessary for the profitable and successful dispersal of the propa- gating bodies. Even the germination of a large number of seeds and spores in light only may be regarded as a similar association of a stimulus with other vegetative conditions. It is true of course that spores of certain pteridophytes must have light-exposure to enable the chlorophyl-apparatus to construct building material for germina- tion and growth, but in the larger number of instances illumination acts simply as a signal indicative of the presence of other necessary factors. The intensity of light necessary to constitute a phototropic stimulus varies enormously with different species, and with the developmental state of the individual. Using a normal candle burning 7.78 grams of paraffine per hour at a distance of one meter as a standard it has been found that an illumination of .00033 to .o6 meter candle con- stitutes the minimum in seedlings of the most delicately organized species examined. The optimum effect in curvature is obtained in the same plants with an intensity of .11 to .44 meter candle, and these intensities must be increased a hundred to a thousand times to reach the maximum. Increase of the intensity beyond the maximum may result in changing the character of the response in such manner that the organism will curve or move away from the source of the rays. The more refrangible rays are chiefly active in such effects, and the amount of increase in the intensity necessary to constitute a stimulus is not more than 18 per cent. in some instances. In addition to the reactions described above the plant shows other forms of response to intensities of illumination by photeolic and pho- tolytic movements which bring the cell-constituents into adaptive rela- tions with radiant energy by which injurious activity of the trans- piratory and other functions are avoided. All efforts to establish a connection between the action of light on the enzymes or other cell contents as a primal and direct cause of the reactions in question have failed. Light has undoubtedly exerted a predominating influence in the development of the prevailing types of vegetation, the form and structure of the body and its members being largely determined by 204 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. the experience of the plant with respect to the nature, intensity, and direction of the rays which have impinged upon them. It would hardly be justifiable to say that light has originated or caused dorsiventrality in the vegetable kingdom: the causes must lie deeper and be infinitely more complex. Light of course has been one of the complex conditions to which dorsiventrality is a primary and basic developmental adaptation. Given the capacity of dorsiventral or- ganization or development however in individuals, and its occur- rence is often directly subject to the determinative and inductive action of illumination. It is to be said in this connection that the use of the term ‘‘ directive ” to designate morphogenic influences exerted by light, as has been done by Goebel, is withal, not in harmony with current usage, this term having long been applied to the action of the rays in inducing phototropic, photeolic and photolytic movements of the axes of the shoot and its members or of the body in general.'* Chief among the determinative influences exerted by light are to be mentioned the anatomical differentiations which may ensue as a result of its action, by which an organ may become dorsiventral and the positions of the dorsal and ventral surfaces altered. It is well known however that any form of dorsiventrality once assumed by the body or any of its members may not be changed, or reduced by altered conditions of illumination. A second phase of induced bilaterality is that in which organs are induced or suppressed upon comple- mentary surfaces. This form of symmetry is often directly reversible by changed conditions of illumination, particularly among the thallus- like forms of the lower plants. Not only does the illumination de- termine the relative position of the dorsal and ventral surfaces, but it may also guide the polar differentiation, the apex and base of plant- axes being formed in developing spores with respect to the direction of the rays. The association of different developmental stages of a plant with various intensities of illumination and the hindrance of procedure in every other instance in which the intensity of the light is beyond — certain limits is a somewhat more complicated and delicate mani- festation of the determinative influence of light upon the induction or suppression of organs. The actionin question must be purely stimu- lative in its character, and for every stage an optimum, maximum and minimum of intensity might theoretically be established. '® Goebel. Influence of Light. Organography of Plants. Eng. Ed., 227-259. 1900. a ae MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 205 The length of the main axis and its branches, and the superficial extent of foliar organs have been found to depend upon the intensity of the illumination in a large number of species. Such variations in stature are coupled with corresponding alterations in internal struct- ure. Adaptations of this character may be generally attributed to responses to the transpiratory conditions set up and to various mechanical factors. The marked features of alpine types consisting chiefly of dwarfing of the shoot and additional checks upon transpira- tion may be ascribed in part to the increased intensity of the illumi- nation at higher levels due chiefly to the lessened absorption by the atmosphere of the blue-violet end of the spectrum, and to the altered moisture-relations by which the danger of drying out is much greater than upon plants at lower levels. The change of the light-conditions entailed when aérial members are converted functionally into underground organs is over-balanced by the altered mechanical conditions, so that only a part of the differences may be ascribed to altered illumination. The character of the stresses to be borne are so altered that the develop- ment and arrangement of the me- chanical tissues are necessarily dif- ferent from those of homologous aérial stems. Then again, the humidity of the medium is so much greater, and the transpiratory conditions so dif- ferent that the epidermal surfaces and subepidermal tissues are widely variant from those of aérial stems and branches. The terms ‘‘ light” and ‘ illumin- ation” have been used in the preceding Fic. 157. Renunculus Asiaticus. discussions to allude to the ordinary 16D, leaf developed in discontinuous Gxposures of plants to daylight of an °rmal illumination; 16C, leaf de- : : =e . veloped in continuous electrical il- intensity varying with the local en- lumination. 16N, etiolated leaf. vironment and longitude, and alterna- After Bonnier. ting with the nocturnal periods of dark- ness. A reviewof the records of investigations cited in the opening section of this book brings out most conclusively that the greater major- 206 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. ity of plants exhibit divergences from normal growth and development whenever cultivated under conditions in which the customary occur- rence of illumination and darkness is varied. The effect of one departure, in which plants are cultivated in complete darkness, has been the subject of an enormous number of investigations as pre- viously indicated. ‘The amount of experimental evidence at hand bearing upon the influence of continuous illumination upon plants is comparatively meager, the most important contribution to the subject, from a botanical point of view, having been made by Bonnier in 1895 (see page 27 of this Mem- Oir).72 The continuous electric illumination to which Bon- nier subjected the plants used in his experiments was of suchintensity that a liber- ation of oxygen from aqua- tic plants under the same conditions took place at about one third the normal rate at which the process ensued in sunlight. Par- ticular emphasis is to be laid upon this fact in view of the well-grounded con- clusions, to which refer- ence is made above (p. 204), that the separate stages of development of a plant, or of the different organs, are associated with certain intensities of illumi- Fic. 158. Carpinus Betulus. 1C, leafy branch nation. An intensity below from small tree in Soulnuous eleetaica) We ee the normal of full sunshine om ety branch in normal discontinvoet would be favorable for cer tain action and unfavorable for others, and it is to this continuous and long-continued con- 144 Bonnier, G. Influence de la lumiére électrique continue sur la forme et la struc- ture des plantes. Rev. Gen. d. Bot. 7: 241, 269, 332, 407. 1895. NN ——————————< eer ett eo ey MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 301 Etiolated leaves of ‘‘ stemless ” plants also were much poorer in pro- teids than green organs of the same species, while etiolated leaves borne on aérial stems were richer in protein than normal green leaves. These results were obtained from examinations of etiolated and normal specimens of beans and wheat. The data obtained in my own analyses may be restated in the form of the following tables: Water, Dry MareriIAL AND AsH IN Corms oF Arésaema. Normal. First Etiolation. Second Etiolation. Water 89.84 per cent. 82.50 per cent. 80.14 per Cent. Dry material 19.16 e 17.50 eS 19.86 . Ash in fresh material 306 se .286 ve 453 ub Ash in dried material 2.44 oe 1.63 ee 5.89 ne Water, AsH, AND DrieD MATERIAL IN LEAVES OF Ardsaema. Normal. First Etiolation. Second Etiolation. Water gI.105 percent. 93 per cent. 96.24 per cent. Dried material §.895 es 7 e 3.76 He Ash in fresh material -404 BE -519 es 366 ue Ash in dried material 4.54 fs 7-43 He 9-73 oe It is thus to be seen that the proportion of water in corms formed during etiolation is less than under normal conditions, and this de- crease continues in the second etiolation, in which the percentage is higher than that of resting corms dried in the air at ordinary tem- peratures (p. 61). At the same time the proportion of dry material in- creases, although the actual amount is less of course. The propor- tion of ash in corms formed as a result of the first etiolation is less than the normal, and undergoes an increase in the second season’s growth in darkness. In like manner the proportion of ash in the dried material is less than the normal in corms resulting from the first etiolation, but increases during the second etiolation to a per- centage much greater than the normal in fresh corms and greater even than in air-dried corms. These results point quite conclusively to an accumulation of ash in the body of the plant during its succes- sive seasons of development when confined in the dark room. The proportion of water in the leaves is greater than the normal during the first etiolation and shows a further increase during the 302 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. second growth in darkness. The dried material undergoes an in- verse alteration. The proportion of ash in the fresh material in- creases during the first etiolation and decreases in the second to a point below the normal. When a comparison is made with the dried material, however, the proportion of ash is seen to increase during the first as well as in the second etiolation, in which it about doubles the normal proportion. The small proportion apparent in fresh material of the second etiolation is due to the great increase in the percentage of water present. ~The increase in the proportion of ash to the dried material during the first and second etiolations is seen to be due to the lessened formation of dried material rather than to any positive increase in the amount of mineral matter carried up into the leaves as an accompaniment or result of etiolation. André found that an increase of temperature of the higher plants between 15 and 30° C. increased the amount of silica carried up in etiolated shoots. The amount of calcium carbonate was decreased and the quantity of potassium and phosphoric acid remained about the same. The proportion of vasculose among the hydrocarbons was increased. It is difficult to account for the increase in the amount of such an insoluble substance as a result of higher temperature and increased transpiration.” Interesting comparisons are afforded by the data obtained by Karsten ** with seedlings of Phaseolus multifiorus, which were allowed to grow 15-20 days in the light and others 25 to 30 days in darkness. By reason of the longer period of development in darkness the total weight of the etiolated plants was much greater than it would be if taken at the same age as the normal examples. The relative com- position of the separate organs is shown in the following tables: PRopoRTION OF DriEpD MATERIAL IN SEEDLINGS OF Phaseolus mulit- Jlorus AFTER KARSTEN. Hypo- 1st 2d and 3d Coty- Leaves. cotyl. Internode. Internodes. Roots. ledon. Average. Normal 15,878 16,646 13,090 12,100 8,379 21,554 15,502 Etiolated 16,959 6,668 8,731 8,194 7,509 17,574 11,431 3See André, G. Action de la temperature sur l’absorption minerale chez les plantes etiolées. Compt. Rend. 134: 668-671. 1902. *04 Karsten, H. Die Einwirkung des Lichts auf des Wachstum der Pflanzen. Jena. 1870. ee ee ET ee MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 303 The following table by Karsten shows the actual amount of fresh and dry material in a lot of plantlets produced by seeds weighing 1,000 grams, under normal conditions and in darkness: NORMAL. Hypo- Ist 2d and 3d Coty- Leaves. cotyl. Internode. Internodes. Roots. ledon. Total. Fresh 722 115 393 222 1,035 1,551 4,041 Dried 114 12.3 51-5 26.8 87 334 626.5 ETIOLATED. Fresh 134 293 1,437 570 832 1,582 4,886 Dried 22.6 19.6 127-3 46.7 62.4 DT 556.2 The superior weight of dry material in the internodes and hypo- cotyl is the result of the greater age of the etiolated specimens, while it is to be seen that the construction of dry matter in the roots has fallen below that of plants with green stems and leaves (see p. 25). The following table by Karsten gives the number of parts of the principal constituents of the dried material (at 105° C.) in 100 parts of normal and etiolated plantlets and in seeds. The figures are given to the nearest decimal of the first place and the data obtained from normal plants is given in the column under A, and from etiolated plants under B. = 3 com) . g 2 = Sie © eon v ° u Kone) ee Mo) | ww : : : ef 3 2 18 x 2 . © Se ae BAL a ; aa A) B | A Bese Be Fats 4.9 | 4.15| 3.5) 3-48; 2.69] 2.54, 3.9 | 3.16) 2.55 3-13| 2.7 | 2.79) 1.18 Sugar Bier .39| .585| .166] .438 .02] .39] | 3.86] 2.93} 8.84 Gums 20.21/18. | 19.2 |18.1 |14.9 |14.6 |18.89 15.53/14.5 |I14. |16.4 |13.1 |12.9 Starch Poel El QO lee Aa ae 43.50) 2:5)° 2.2 4 4.7) | 4.85 1TG:Qn EO. eos Cellulose 9.7 | 9.1 | 21.3 |15-9 |22.7 |20.3 |20. (24. |18.9 |19.3 | 3.9 | 4. | 4- Protein 36.3 153-3 | 24.4|35-7 |27-5 143-1 |29.4 38.1 |24.41|33.8 |21.9 |20.2 |21.9 Ash 5.9 |10.9 ute |e AL 2e| Os Bull Os2) Oy Sale y.3) OS | EGAN eet Il ALG: Residue 21.7 | 2.9 | 28.8 |12.9 |24.4 | 9.3 |16.9 | 7.4 |29.3 |19. |26.4 |32.7 |36. Nitrogen 5.8 | 8.5 | 3-9| 5.7 | 4-4 | 69 | 4.7 | 6.1 | 3.9 | 5.4 We Bonin es The proportion of fats is seen to decrease in the leaves during etiolation, to remain stationary in the hypocotyl, to decrease in the stem, and increase in the roots. The proportion of sugar undergoes a marked decrease during eti- olation throughout the entire plant, the greatest percentage remaining 304 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. in the cotyledons. The amount of starch was greatest in etiolated leaves, normal hypocotyls, etiolated first internodes, normal inter- nodes above etiolated roots, and normal cotyledons. Cellulose was present in smaller proportions in etiolated leaves, hypocotyls and lower internodes, and in greater proportions in etiolated upper internodes, roots and cotyledons. These determinations of cellulose are undoubtedly faulty, especially in the stems. Protein was present in greater proportion in etiolated leaves, hypocotyls, stems and roots, and in smaller proportion in cotyledons than in the normal. These results do not agree with those obtained later by Palladin (p. 23). The amount of ash in a given weight of mate- rial was greatest in etiolated leaves, hypocotyls, internodes and roots, and less in cotyledons than in the normal, which is in general agree- ment with the results obtained in my own analyses. Rzentkowsky’s™ examination of seedlings of Phaseolus multiforus \ed him to con- clude that etiolated plants do not take up mineral substances from the substratum a conclusion which is undoubtedly wrong, as demon- strated by André and myself. THE RATE AND MODE OF GROWTH AS AFFECTED BY LIGHT AND DARKWNESs= The rate of growth of any organism varies in such manner that a more or less irregular acceleration is shown during the earlier stages of development until a maximum of increase is reached, when a simi- lar diminution brings the action to zero. Minor maxima are also shown before or after the major in some instances. In addition to this major movement which traces the curve of the grand period of growth of the organism, minor deviations occur, which may be due to alterations in temperature, food-supply, moisture and other causes. Running through the major and minor alterations as above there are seen to be more or less regularly recurring accelerations and dimi- nutions of the rate, which have been shown to be due to a rhythm 204 Rzentkowsky, T. Untersuchung ueber Entwickelung des etiolirten Phaseolus multifiorus. Mitth. d. Universitit z. Warschau. 1875. Abstract by Batalin in Bot. Jahresber. 4: 745. 1875. : 205 Presented before the Botanical Society of America, at Washington, D. C., Jan. I, 1903. MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 305 set up by inherent causes. Baranetzky ™ concluded that the rhythm exhibited by plants in a dark room was an after-effect due to the lasting influence of alternating exposures to daylight and darkness, and pointed out that in continued confinement the diurnal periodicity was lost and the variations no longer occurred with sufficient regu- larity to constitute a rhythm. Sachs seems to have been the first to formulate the opinion that light retards growth and his position with regard to minor periodicities may be best given in his own words: ‘I, on the contrary, am of the opinion that in the plant, or at any rate in its growing parts, periodic variations occur in some way quite independent of variations of temperature and light; and these, as I conclude from Baranetsky’s observations, may continue for periods of very different lengths. If now the plant is subjected to the regular alternation of day and night, and the variations of temperature are very small, the above-mentioned influences on growth make their appearance, by which its maximum is transferred to the morning hours, and its minimum to the evening, the above-mentioned period- icity arising from purely internal causes being concerned as the weaker factor in a definite daily period of time.” Sachs *” did not agree with Baranetzky however in the assertion that the daily periodicity of plants in darkness was an after-effect of light or temperature, and Vines took the position that the coincidence of the variations with those of normally illuminated plants was prob- ably accidental, although he conceded that the daily periodicity of a plant continued for several days after it had been confined in a dark chamber. Both Sachs and Vines” held that it was improbable that the periodicity of fully etiolated plants was due to after-effects ; indeed Sachs adduces the fact of periodicity in such a plant as a refutation of the theory of after-effects in the matter, and likens it to the starting of pendulum spontaneously after it had come to rest. It is to be seen however, that geotropic and other stimulatory effects may be hindered and the response delivered long afterward, and Darwin and Pertz have shown by a beautiful series of experi- ments that geotropic rhythms may be induced in stems, which are maintained after the stimulus is withdrawn. The position taken by 206 Baranetzky, J. Die tagliche Periodicitit im Langenwachstum der Stengel. Mem. d. I’Acad. Imp. d. Sc. de St. Petersbourg. Ser. 7. 1879. 27Sachs. Physiology of Plants. Eng. Ed., p. 560. 1887. 208 Vines, S. H. Physiology of Plants. p. 403. 1586. 306 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. Baranetzky therefore, that the periodicity of growth maintained by a plant after it has been deprived of illumination, is an after-effect, and which supported by Vines seems well defended, to whatever this daily periodicity may be due. Furthermore, it might be expected an organ would carry on growth with a rhythm due to the action of factors concerned with an extremely early stage of its existence. Itis probable that the behavior of any single species however, may not be safely predicted. Thus the auxanometric measurements of Ar7saema triphyllum disclose a rhythmic action, quite as well marked as that of the normal plant, when grown in a dark room at constant tem- peratures (pp. 68-70). The measurements of a leaf of Quamasza during a continuous period of fifty days in a dark room at a constant temperature (p. 86) gave opportunity for observations of growth under conditions in which the food-supply, moisture, temperature and darkness were practically uniform. A consideration of the facts shown in the curve plotted from the auxanometric data brings to light the fact that the variations in this instance were exceedingly irregular, and seemingly subject to no rule of any kind. No control observations were made on this species for the purpose of obtaining the variations in normally grown plants. The variations of Avzsaema, on the other hand, were fairly parallel to those of the specimens under normal alternations of daylight and darkness with the temperature fluctuating. The observations described in this memoir, together with the records of previous investigations upon etiolation demonstrate most conclusively that the growth of the aérial organs of green seed plants in darkness is not accompanied by the usual degree of differentiation of the several tissues. The amount of growth, or increase in volume, that may be accomplished by the shoot by the extension of the im- perfectly developed tissues in the absence of illumination is subject to great variation. In many species the total length, diameter and volume of the etiolated shoot, and its various members is not so great as in the normal, and the rate of growth may not be so rapid as in the normal. The buds and seeds of a number of species, and also the spores of many pteridophytes will not awaken from a resting condition and begin the growth leading to the development of the shoot except under the influence of light. On the other hand, some species of the higher plants, as well as some of the lower forms, carry on the growth of the main axis at an accelerated rate in dark- MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 307 ness, and to such an extent that shoots are formed which may exceed the normal both in length and diameter. It is obvious that, in the above phenomena, the effects are due to the stimulating influence of light, and of darkness (or absence of light). The differentiation of the tissues, and the development of certain reproductive bodies constitute positive reactions to the stimu- lating influence of the rays, and the exaggerated elongations shown by many shoots is a response to darkness, which may be adapta- tional in its character, and which might serve to lift the chlorophyl- bearing organs past an imaginary obstruction into illumination. The failure of a large proportion of the forms examined to make an accel- erated or exaggerated growth when freed from the influence of light, even when provided with an adequate food supply, shows that light has no invariable and universal relation to increase in length, or thickness, or to the multiplication or increase in volume of the sep- arate cells. When a green plant is suddenly deprived of illumination a marked acceleration of the rate of elongation ensues, and a diminution ensues when a plant is brought from darkness into light, which Pfeffer, as a result of a consideration of the investigations upon this point, esti- mates to amount to changes in the rate not greater than fifty per cent. of the existing rate. Many of the observations bearing upon this point were made with plants which do not exhibit an abnormal elon- gation in darkness. In my own investigations the peduncles and scapes of Arzsaema, which had ceased to make an amount of growth equal to a total of 1 mm. per day, underwent a comparatively enor- mous acceleration which reached a maximum about twenty-four hours after being deprived of illumination, and then decreased to a minimum correspondent to the original rate in about a hundred hours. Arisaema is a plant which shows a marked adaptational elongation in darkness during etiolation, and this increase may only be ascribed to the stimulative action of darkness, since it would be an obvious ab- surdity to ascribe such an enormous increase in rate to the absence of any direct or paratonic action of light. This seems still more justifiable when it is pointed out that the rate of growth is never di- minished by the action of light to the extent that it is by temperature. It is clear therefore, that no evidence is afforded by the behavior of plants in darkness to support the conclusion that light directly affects the rate of growth, since not all species exhibit increased 308 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. growth when freed from its influence, and the accelerated rate shown by mature organs when placed in darkness may be only ascribed to a stimulative action and an adaptational response. Another aspect of the effect of light on growth remains to be considered. It is well established by hundreds of observations that the rate of growth of a large number of normal greenorgans, or of shoots, decreases when deprived of illumination for a period, such as that of an ordinary night, or even briefer, and then suddenly exposed to the action of the rays. This has given rise to the generalization that light exerts a direct or paratonic action on growth. Now it has been demonstrated most conclusively that light does not exert any direct effect on the growing region either in the way of influencing cell-division, or the processes depending upon the motility of the protoplasm, or of the material entering into the construction of the membranes. In fact none of the phenomena of etiolation or of diminished growth in light may be ascribed to the direct influence of light upon the tissues or cells concerned but rather upon the organism as awhole. The lessened increase in volume taken into account in measurements of the growth of plants exposed to the action of light may be due to one or both of the following causes. First, it is to be pointed out that the action of the rays on any mass of proto- plasm is to accelerate the rate of transpiration, and the loss of water may be sufficient to cause a decrease in bulk, which might neutralize the outward effects of the actual constructive processes, which may continue uninterrupted during the apparent decrease or cessation of growth. On the other hand, it is entirely probable that some of the apparent retardation may not be due to a direct mechanical influence of the rays, but is a stimulative reaction. That the slowing down of the rate of growth under the influence of light is an irritable response is supported by the behavior of plants exposed to continuous illumination for long periods, such as might occur in the polar re- gions, and which has also been brought about in several series of experiments. Inthe former instance the specimens grown in locali- ties in which the daylight period embraces the entire vegetative sea- son of several months, the shoot and its members did not exhibit an increase, which either in rate or amount would justify the assertion of a direct retarding influence. The same results have been attained in another form by the exposure of growing plants to continuous ex- posure to electrical illumination, or to an illumination in which day- ; 4 | MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 309 light was supplemented by nocturnal illumination from electric arcs, or flames. In all such instances the amount of growth, as indicated by the length of the shoots and of the separate members, was greater than under ordinary conditions of alternating daylight and darkness. If light exerted a direct retarding, or paratonic influence upon the processes of growth, such results would be impossible. On the other hand, if the slowing down of the increase of shoots when sud- denly exposed to light is due to a stimulative action the continued il- lumination of a plant to the action of the rays would soon result in an accommodation to the continuance of the stimulation, and the be- havior of the plant after becoming attuned to increased illumination would embrace some features due to the altered conditions of nutri- tion, and to the supposedly disintegrating effects of the blue-violet rays on chlorophyl and other substances. INDEX TO CONTENT, Abutilon, 22 Acer, 247, 249, 251, 295 circinatum, 188 rubrum, 188-190, 239, 240, 241, 242, 266 AEsculus, 218, 224, 245, 247, 249, 257, 268 Hippocastanum, 190, 191-194, 196, 230, 231, 239, 290 Agave Americana, 37, 235 Allium, 214 Cepa, §, 38 Neapolitanum, 37, 38, 39, 255, 256 porrium, 10, 39 vineale, 39, 40, 255, 256 Allosorus sagittatus, 34 Aloe obliquum, 7 Amarylits, 214, 269 Sormosissima, 16 Johnsonit, 40 Amelung, E., researches of, 10 (Ueber Etiolement. Flora. 78: 204, 1894), 26, 273 Amorphophallus, 48, 220, 257, 269, 300 Eiviert, 40, 41, 42 Anchusa officinalis, 22 Andre, G. (Action de la temperature sur Vabsorption minerale chez les plantes etiolées. Compt. Rend. 134: 668-671, 1902), 302 Aneimia Phylittidis, 34 Antirrhinum majus, 17 Apios, 222, 224, 2247; 228, 220, 246, 247, 251, 268 Apios, 42, 46, 194 Apium graveolens, 8 Afplectrum, 215, 221, 255, 256, 269 spicatum, 47, 48 Aposerts, 265 foetida, 262 Aquatics, etiolation of, 215-218 Arisaema, 42, 215, 268, 271, 286, 296, 297, 301 Dracontium, 48-50, 2 triphyllum, 50-71, 296, 306, 307 Aristolochia, 71-73, 215, 219, 222, 225, 226, 228, 229, 264 Arodes (see Calla), 220, 258 Arum maculatum, 221, 231 Askenasy, E. (Ueber der Einfluss des Lichtes auf die Farbe der Bliithen. Bot. Zeitung. 34: 1, 27, 1876), 17, 273 Asparagus, 247, 252, 264, 268 officinalis, 73-75, 238, 263, 295 Aspidium molle, 34 spinulosum, 34 Asplenium alatum, 34 231, 257 230, 231, 257, 221, 220, AND TO LITERATUR Asplenium lastopterts, 34 platyneuron, 75-78, 253, 278, 296 Aster divaricatus, 77, 79, 243, 246, 249, 251, 263, 264, 286 patulus, 30 Atriplex hortensis, 30 Avena sativa, 6 Baccharts halimtfolia, 80, 239, 240, 266 Baeomyces, 21 Bailey, on influence of electrical illumina- tion, 293 on effect of light on Petunza, 276 Bailey, L. H. (Some preliminary studies of the influence of the electric arc lamp upon greenhouse plants. Bull. No. 30. Cornell Univ. Agric. Exp. Station. 1891), 210 ; Second report upon electro-horticul- ture. Bull. No. 42. Cornell Univ. Agric. Exp. Station. 1892), 210 Third report upon electro-horticul- ture. Bull. No. 55, Cornell Univ. Agric. Exp. Station. 1893), 210 Baranetzky, J. (Die selbstindige tagliche Periodicitit im Langenwachstum der Internodien. Bot. Zeitung. 35: 639, 1877), 17, 305 Batalin, A. (Ueber die Wirkung des Lichtes auf die Entwickelung der Blat- ter. Bot. Zeitung. 29: 669, 1871), 11, 13, 283 Beans (see Phaseolus), 1, 7 Beech (see Fagus), 26 Beet (see Beta vulgaris), 211 Begonias, 8, 274 Benecke, W. (Ueber Cultur Bedungun- gen einiger Algen. Bot. Zeitung. 56: ist Abth. 89, 1898), 33 Berthold, G. (Beitrige zur Morphologie und Physiologie der Meeresalgen. Jahrb. f. Wiss. Bot. 13: 569. 1883), 25 Beta vulgarts, §, 9, 262 Beulaygue, L. (Recherches physiolog- iques sur le dévelloppement de la fleur. Montpelier. 1901), 275, 290 Bicuculla, 221, 259, 260 cucullaria, 80 Boehm (Die Nahrstoffe der Pflanze. 1886), 20, 283 Bombax, 234 Bonnet, Ch. (Usage des feuilles. p. 254. 1754), 1 . Bonnier, G. (Influence de la lumieére électrique continue sur la forme et la structure des plantes. Rev. Gen. d. Bot. 7 + 241, 289, 332, 407. 1895), 28, 194, 196 310 INDEX. Bonnier, on influence of electric illumina- tion on plants, 205, 206, 207, 208, 210, 275, 292 Bonnier, on etiolates, 284, 293 Bonorden (Handbuch der Mykologie. 1851), 51 Borodin, J (Physiologischer Untersuch- ung tiber die Athmung der beblit- terten Sprosse. Arb. d. St. Petersb. Ges. d. Naturf. 7: 1-114, 1876. Ab- stract in Bot. Jahresber. 4: g19. 1876), 16 (Ueber die Wirkung des Lichtes auf einige hédhere Kryptogamen. Mel. Biol. 6: 529. 1867), 34 Botanical Convention, Weekly, 280 Botanical Society of America, 304 li obliguum, 80-82, 243, 244, 255, 27 Botrytis cinerea, 22 Bowitea, 214, 222, 226, 227, 228, 229, 236, 238, 247, 256, 268 volubilis, 82-84 Brassica, 9, 265, 271 campestris, 83-85, 243, 244 Napus, 227 Brefeld (Ueber die Bedeutung des Lichtes fiir die Entwickelung der Pilze. Bot. Zeitung. 35 : 386. 1877, also Sitzungsber. d. Ges. Naturf. z. Berlin. April, 1877), 17 Brenner, W. (Untersuchungen an einigen Fettpflanzen. Flora. 87: 387. 1900), 32, 237 Brown and Escombe (The influence of varying amounts of carbon dioxide in the air on the photosynthetic processes of leaves and on the mode of growth of plants. Phil. Trans. Roy. Soc. 193: 278. 1900, abstract in Nature. 66: 621. 1902), 274, 292 Bryonta, 8, 9, 230 dioica, 222, 224, 230 Buchenau, F. (Die Wachstumsverhalt- nisse von, Bowzea volubilis. WHkr. fil., Abhandl. d. Naturw. Ver. z. Bremen. 6: 433), 84 Bulbs, etiolation of, 216, 217 Bullot, E. (Sur la croissance et les cour- bes du Phycomyces. Ann. d.1. Soc. Mi- croscopique d. Belge. 21: 84. 1897), 31 Busch, H. (Untersuchungen ueber die Frage ob das Licht zu den unmmittel- baren Ledensbedingungen der Pflanzen, oder einzelner Pflanzenorgane gehort. _ Inaug. Diss. Bremen. 1889), 23 allgemeine Cabomba, 217 Cactus speciosus, 8 Caladium esculentum, 85, 86, 215,219, 257; 258 Calla, 215, 257, 258 (cultivated), 86, 87 palustris, 87, 216 20% Camassia (see Quamasia), 87, 89, 256 Cambium in etiolated stems, 251 b Canna, 219, 257 (cultivated), 88-91 Cannabis sativa, 12, 23, 30 Capsella, 238 Carpenter, M. B. (Vegetable physiology, and systematic botany. p. 198. 1848), 6 Carpinus Betulus, 206 Castanea dentata, 91-93, 99, 230, 231, 239, 250 Caulerpa, 25, 216, 217, 218 Ceratophyllum, 27, 217, 218 Ceratopteris thalictroides, 34 Cereals, etiolation of, 115 Chapin, P. (Einfluss der Kohlensiure auf das Wachstum. Flora. 91: 348- 379- 1902), 275 Chara, 217 Cheiranthus Chetrit, 9 Chemical composition, influence of etiola- tion on, 300-304 Chenopodium album, 30 Chestnut (see Castanea), 91-93 Cicuta, 259 maculata, 93-94 virosa, § Claytonta Virgintca, 94, 95 Climbing plants, etiolation of, 222-230 Cocoanut (see Cocos nucifera), 95-97 Cocos, 247 nuctfera, 95-97, 230, 231, 257, 258 Coix Lachryma-Jobi, 97, 230, 231, 267 Collenchymatous layers in etiolated stems, 249 Colocasta, 97, 257, 258 Colutea arborescens, 29 Coprinus stercoriarius, 279 Corbett, on the effect of artificial illumi- nation on plants, 275 Corbett, L. C. (A study of the effect of incandescent gas-light upon growth. Bull. No. 62. W. Virginia Exp. Station. 1899), 211, 293 Corms, etiolation of, 216, 217 Cornus alterntfolia, 97-100, 115, 189, 239, 240, 242, 246, 250, 251, 266, 295 Coronilla, 210 Crataegus monogyna, 16 Crocus, 8 vernus, 271 Cucurbita, 859; 10) 145)205 30,) 2295) 270, 272, 273, 274 Melopepo, 22 Curtel, M. Y. (Recherches physiologiques sur la fleur. Ann. Sc. Nat. VIII. 6: 220. 1897 ), 29 Cyclamen, 100, 101, 219, 259, 260 Cynoglossum officinale, 22 Cypripedium, 264, 267 montanum, LOL, 102, 243 Dahlia variabilis, 8, 22 | Darkness-rigor, II, 12 272 Dark room at N. Y. Bot. Garden, 36 Dark-chamber, portable, 36 Darwin, F. (Etiolation asa phenomenon of adaptation. Jour. Roy. Hort. Soc. 19: 345. 1896), 28, 284 researches of, 305 Davy, H. (Elements of agricultural chem- istry. pp. 208, 209. 1815), 4 De Bary (Recherches sur le développe- ment de quelques champignons para- sites. Ann. Sc. Nat. IV. 20: 40, 54. 1863). 5 DeCandolle, A. P. (Expériences relatives 4 Vinfluence de la lumiere sur quel- ques végétaux. Mem. Math. et. phys. Inst. Nat. Paris. 1: 332. 1806. Presented in 1799), 3 (Physiologie végétale, 3 : 1069. 1832), 4, 280, 300 DeCandolle, C. (Etude de Jl’action des rayons ultra-violet sur la formation des fleurs. Arch. des Sc. Phys. et Nat. Genéve. 28: 265. 1892), 24, 272, 291 Deherain (On influence of electrical il- lumination on plants. Ann. Agron. 7: 551. 1881), 209 De Lamarliére, L. G. (Recherches phy- siologiques sur les feuilles dévellopées a Vombre et au soleil. Rev. Gen. d. Bot. 4: A481 1892), 2 Delphintum exaltatum, 102, 103, 243, 244, 263, 264 De Saussure, Th. (De l’influence de la lumiere sur la germination. Recherches chimiques sur la végétation. p. 21. 1804), 3 Detmer, W. (Die Formbildung etiolirter Pflanzen, in Vergleichende Physio- logie des Keimungsprocesses der Samen. pp. 464-478. 1880), 234 (Ueber den Einfluss verschiedener Lichtintensitaiten auf die Entwick- elung !einiger Pflanzen. Landw. Versuchss. 16: 205. 1873. See also Detmer, Practical Plant Physiology, pp. 404-411. 1898, and Detmer, Vergleichende Physiologie d. Kei- mungsprocesses d. Samen. 1880) ,14 (Ueber Photoepinastie de Blatter. Bot. Zeitung. 40: 787. 1882), 14 Development and differentiation, effect of etiolation on, 246-247 ice isso es leaves of, etiolation of, 259- 203 Dictyostelium mucoroides, 279, 280 Digitalis purpurea, 17 Dioscorea Batatas,\9, 222, 226 Dolichospermum, 274 Draper (Chemistry of plants. York), 6 Dufour, L. (Influence de la lumiére sur la structure des feuilles. Bull. Bot. Soc. d. France. II. 8: 92. 1886), 22] 1844. New | | INDEX. Duhamel du Monceau (Des plantes étio- lées, in La physique des arbres, 2: 155),2 Duration of etiolated organs, 218-222 Dutrochet (Rapport sur un mémoire de M. Payer intitulé: Mémoire sur la ten- dance des racines 4 fuir la lumiere. Ann. Sc. Nat. III. 2: 96. 1844), 6 Echallium elaterium, 22 Electric illumination, effects of, 27, 28 Elfving, F. (Studien ueber die Einwir- kung des Lichts auf die Pilze. Hel- singtfors. 18go), 18, 23 Ellis, D. (Farther inquires into the changes induced in atmospheric air by the germination of seeds, the vegeta- tion of plants and the respiration of animals. p.132. 1811), 281 Elodea, 27, 217 Endive, 211 Endoderm, in etiolated stems, 251 Epidermal cells on etiolated stems, 247— 248 Epiphegus, 270 Equisetum arvense, 34, 103, 104, 238, 278 Ervum lens, 297, 298 Erythrine, 7 Erythronium Hartwegt, 104, 255 Escombe, Brown and (The influence of varying amounts of carbon dioxide in the air on the photosynthetic processes of leaves and on the mode of growth. Phil. Trans. Roy. Soc. 193: 278. 1900), 274 Etiolation, nature of, 280-283 Faba vulgaris, 30 Fagopyrum, 9 Fagus, 246, 250, 251 Americana, 105, 106, 194-197, 226, 239, 242, 267 sylvatica, 195, 196, 239 Falcata comosa, 105, 106, 222, 224, 226, 229, 251 Famintzin, A. (Die Wirkung des Lichts auf das Wachsen keimenden Kresse. Mem. Acad. St. Petersb. 8: p. 13. No. 15, 1865), 13 (Die Wirkung des Lichtes auf Algen und einige andere ihnen nahe ver- wandte Organismen. Jahrb. f. wiss. Bot. 6: 2. 1867); 13 Ficus elasttca, 210 Filix fragilis, 106, 220, 278 Flammarion, C. (Physical and meteoro- logical researches, principally upon solar rays, made at the station of agri- cultural climatology. Juvisy, France, Abstr. Exper. Sta. Record. 10: 103. 1898), 211 Flowers, etiolation of, 268-178 Frank, B. (Lehrbuch der Botanik. 1: 389. 1892), 2 “a rg QA et Sat a NIN Oia 2) te RE _=. ‘ : ae * x a a - ~ INDEX. Frank, on the nature of etiolation, 283-284 Frank, A. B. (Ueber die Lage und Rich- ' tung schwimmender und _ submerser Pflanzentheile. Cohn’s Beitr. z. Biol. d. Pflanze. 1: Hft. 2, 31-86. 1872), 216 Frankfurt, S. (Ueber die Zusammenset- ' gung der Samen und etiolirten Keim- pflanzen. Inaug. Diss. Wilna. 1893), 25 Fries, E. (Systema mycologicum.1: 502. 1821; also3: 265. 1839; and Syst. Orb. Wests 212. 1825),5 Fuchsias, 274 i circaezans, 24, 106, 109, 243, 263, 209 Gardner (London, Edinburgh and Dublin Philosophical Magazine), 6 Gasteria disticha, 109-112, 219, 226, 265 Generative layers in etiolated stems, 251 Gies, Kirkwood and (Chemical studies of the cocoanut and its changes during germination. Bull. Torr. Bot. Club. 29: 321-359- 1902), 95 Gleditsia triacanthos, 113, 230, 233; 239 Gloxinia hybrida, 22 Godlewsky, E. (Abhingigkeit der Stirke- bildung in den Chlorophyllk6rnern von den Kohlensauregehalt der Iouft. Flora. 56: 378. 1873), 14 (Die Art und Weise der Wachstums- retardirenden Lichtwirkung und die Wachstumstheorein. Anzeig. d. Akad. d. Wiss. z. Krakau, Résumés. p- 166. 1890), 20 researches of, 283, 284 (Studien iiber das Wachstum der Pflanzen. Abh. d Krakauer Akad. d. Wiss. Math.-Naturw. Cl. 23: 1- 157, abstract by Rothert, Bot. Cen- tralbl. 55: 34. 1893), 25 (Ueber die biologische Bedeutung der Etiolirungsercheinungen. Biol. Centralblatt. 9g: 481. 1889), 20 (Ueber die Beeinflussung des Wach- stums der Pflanzen durch aeussere Factoren. Anzeig. d. Akad. d. Wiss. z. Krakau, Résumés, p. 206. 1890),20 (Zur Kenntniss der Ursachen der For- minderung etiolirter Pflanzen. Bot. Zeitung. 37 : 81, 97, 113,137- 1879), 19 Goebel (Influence of light, Organog- raphy of Plants. Eng. Ed., 227-259. Ig00), 204 (On relation of illumination to sporo- phylls and leaves. Flora. 80: 116, 1895), 275 Goebel, G. (Organography of Plants. Part I., pp. 231, 244, 248. 1900), 215, 238, 272 Goebel, K. (Organographie der Pflanzen. Part II., p- 432. 1898), 200 Part Il. p. 499. 1898), 262 313 Goebel ( Ueber die Einwirkung des Lichtes auf die Gestaltung der Kakteen und anderer Pflanze. Flora. 80: 96. 1895 ), 26 Goff, E. S. (Influence of light on the length of the hypocotyls in Indian corn. Science. 13: 395. 1901), 32 Grantz, F. (Ueber den Einfluss des Lichtes auf die Entwickelung einiger Pilze. Leipzig. 1898), 18, 30 Green, J. R. (Action of light on dias- tase, and its biological significance. Proc. Roy. Soc. 188: 169. 1897), 29 Gris, A. (De étiolement, Recherches mi- croscopiques sur la chlorophylle. Ann. Nat. Sei. IV. 7207. 2857), 7 Guarequi, 197, 198 Guillemin, C. M. (Production de la chlorophylle, et direction des tiges sous l’influence des rayons ultra-violets, cal- orifiques, et lumineux du spectre solaire. Ann. Se. Nat: IV. 7: 154. 1857), 7 Hales, S. (Statical Essays. 1: 334. 1727; also p. 336; ed. of 1769), 1, 280 Heckel, E. (Du mouvement végétal. Paris. 1875. Review by Pfeffer in Bot. Zeitung. 34: 9. 1876), 17 Helianthus annuus, 8, 9, 16, 25 tuberosus, 30 Hellebore, 267 Helleborus niger, 28, 208 Hemerocallis, 113, 214, 255 Herbaceous biennials and perennials, etio- lation of, 243-246 Hicoria, 113-114, 189, 218, 224, 250, 251 minima, 114-115, 230, 239 ovata, 115-116. 230, 239 Hieracium Pilosella, 32 Hill, J. A. (Anatomy of plants. 1759)» 242 Hippurts vulgaris, 217 Hordeum vulgare, 6 Horse-chestnut (See AZsculus) 26 Humulus, 8 Lupulus, 30 Humboldt, observations of, 2 Hyacinthus, 8, 9, 116-117, 214, 255, 256, 268 p. 213. ortentalis, 17, 27 Hydrastis Canadensis, 117, 118, 243, 2445 246, 247, 259, 260, 263, 269 Hydrocharis Morsus-ranae, 2 16 Hypopitys Hypopitys, 119, 243, 269, 270, 277 Hura crepitans, 243 Hymenomycetes, relation to light, 5 Ibervillea Sonorae, 197, 198, 222, 224, 229, 238, 247 Illumination of etiolated plants, 295, 295 Impatiens, 274 Inflorescences, etiolation of, 268-278 Ipomaea, 226, 262, 265 314 Ipomaea Batatas, 120, 243 purpurea, 10, 223 Tris, 8, 120-123, 255, 256 pumila, 271 Istvanffi, G. (Influence of light upon the development of flowers. 1890), 22 Jost, on etiolation, 290 Jost, L. (Ueber den Einfluss des Lichtes auf das Knospentreiben der Roth- buche. Ber. d. Deut. Bot. Ges. 12: 188. 1894), 26, 195 (Ueber die Abhiangigkeit des Laub- blattes von seiner Assimilations- thatigkeit. Jahrb. f. wiss. Bot. 27: 403. 1895), 26 Jalapa, 9 Kalanchoé, 274 Kalmia latifolia, 210 Karsten, H. (Die Einwirkung des Lichtes | auf das Wachstum der Pflanzen beo- bachtet bei Keimung der Schmink- bohnen. Inaug. Diss. Jena. 1870), 13, 302, 303 ( Vergleichenden Untersuchungen von in Lichte und Dunkeln gezogenen Pflanzen. Der Chem. Ackersman. No. 3. 1870), 13 Kirkwood and Gies (Chemical studies of the cocoanut and its changes during germination. Bull. Torr. Bot. Club. 29: 321-359. 1902), 95 Klebs, G. (Die Bedingungen der Fort- pflanzung bei einigen Algen und Pilzen. 1896), 28 (Zur Physiologie der Fortpflanzung einiger Pilze. Jahrb. f. wiss. Bot. 35: 140. 1900), 31 Klein, L. (Ueber die Ursachen der aus- schliesslich nachtlichen Sporenbildung von Botrytis cinerea. Bot. Zeitung. 43: 6. 1885), 22 Klemm (Desorganizationserscheinungun- gen der Zelle. Jahrb. f. wiss. Bot. 28: 627. 1895), 27 Klemm, P. (Ueber Caulerpa prolifera. Flora. 77: 460. 1893), 25 Knight, T. A. (On a method of forcing rhubarb in pots. Trans. Hort. Soc. Lond. 3: 154. 1820. See also a selec- tion from the physiological and horti- cultural papers published in the Trans- actions of the Royal and Horticultural Societies. 1841), 4 Koch (Abnorme Aenderungen wachsender Pflanzenorgane durch Beschattung. Ber- lin. 1872), 15 Krabbe, G. (Entwickelung, Sprossung und Theilung einiger Flechten Apothe- cien. Bot. Zeitung. 40: 93. 1882), 22 Kraus, C. (Ueber einige Beziehungen des Lichtes zur Form und Stoffbil- INDEX. dung der Pflanzen. Flora. 61: 145. 1878), 19, 235 (Ueber einige Beziehungen’ des Lichtes zur Form- und Stoffbildung der Pflanzen. Flora. 61: 145. 1878), 235 (Ursachen der Forminderung etio- lirter Pflanzen. Bot. Zeitung. 37: 332- 1879), 15 (Pflanzenphysiologischen Untersuch- ungen, VI. Wachstum und Chloro- phyllbildung. Flora, 58 : 346. 1875), “S Kraus, G. (Ueber die Ursachen der Forminderungen etiolirender Pflanzen. Jahrb. wiss. Bot. 7: 209. 1869), 11 | Kraus, G. (Ueber die Wasservertheilung in der Pflanze. I. Halle. 1879; III. Die tigliche Schwellungsperiode der Pflanze. 1881; IV. Die Aciditit des Zell- saftes. 1884), 11 Kraus, G. (Versuche mit Pflanzen im farbigen Licht. Abdruck a. d. Sitzungs- ber. d. Naturf. Ges. z. Halle. 1876), 11 Kraus, G., investigations of, 281, 282, 283 Lasareff, N. (Ueber die Wirkung des Etiolirens auf die Form der Stengel. Beil. z. Protocoll d. 45th Sitzung. d. Naturf. Ges. a. d. Univ. z. Kasan. Ab- stract in Bot. Jahresber. 2: 775. 1874), 14, 234 Leaves, etiolation of, 253-255, 263-268 with parallel venation, etiolation of, 255, 256 Leavitt, R. G. (Subterranean plants of Epiphegus. Bot. Gazette. 33: 376. 1902), 270 Lendner, A. (Des influences combinées de la lumiére et du substratum sur le dévéloppement des champignons. Ann. Sc. Nat. VIII. 3: 60. 1867), 29 Lenticels, on etiolated stems, 247 Lepidium sativum, etiolation of, 3, 11, 12 Lettuce, 210, 211 Léveillé (Considerations mycologiques. 1846), 5 Light, manifold relations to shoot, 202— 20 shataicopre effect of, 203 modes of influence upon plants, 201 morphogenic influence of, 204, 205, 20 Link, D. H. F. (Grundlehren der Anat. u. Physiol. d. Pflanzen, p. 291. 1807), Linnaeus, observations of, 2 Linum grandifiorum, 9 Livingston, B. E. (Further notes on the physiology of polymorphism of green algae. Bot. Gazette. 32: 298. 1901), BZ Lobelia erinus, 272 FA INDEX. Lupinus albus, 14, 293 Lycopodium lucidulum, 198, 199, 253 Lysimachia terrestris, I2I-125, 234, 244, 246, 247, 251, 263, 267 MacDougal, D. T. (Critical points in the relations of light to plants; read before the Society for Plant Phys- iology and Morphology, Baltimore Meeting, Dec. 28, in Science. 13: 252. Investigations of, 35 (Practical text-book of plant physiol- Ogy- pp- 291, 292. Igor), 88, 201 (Relation of the growth of foliage leaves and the chlorophyll func- fon. Jour. Linn. Soc. 31: 526. 1896), 28, 292 (Seedling of Arisaema. Torreya. 1: 2am tQOL), SO, 221 (Symbiotic saprophytism. Botany. 13: 1. 1899), 47 (Vegetative propagation of Lysi- machia terrestris. Bull. N. Y. Bot. Garden. 2: No. 6. p.82. 1901), 125 Maige, A. (Recherches biologiques sur les plantes rampantes. Ann. Sc. Nat. Boteoscr. §. 1%: 345. 1900), 32, 215 Manda suaveolens, 226 Maple, 26 Marchantiaceae, germination of gemmae of, 28 Marchantia polymorpha, 29, 294 Mariolle, A., drawings by, 37 Mees, observations of, 2 Menispermum Canadense, 125-128, 220, 222, 224, 225, 226, 228, 229, 246, 247, 248, 249, 251 Mentha crispa, 22 piperita, 22 sativa, 32 Mer, E. (Recherches sur les anomalies de dimensions des entre-noeuds et de feuilles étiolées. Bull. Bot. Soc. d. France. 22: 190. 1875), 16 Miagrum sativum, etiolation of, 3 Milde. 1901 ), 202, 216 Annals of ead iC. 23:2), 34 Milla unifiora (see Tritelia) 182, 184, 256, | 269 Mimosa, 12, 26 Mimulus Tillingit, 274 Minnesota, University of, at, 36 Mirabilis, 9 Mobius, M. (Ueber einige an Wasser- pflanzen beobachtete Reizerscheinun- gen. Biol. Centralb. 15: 1. 1895), 27 Monocotyledons, petiolate leaves, etiola- tion of, 257, 259 Montagne (Esquisse organographique et physiologique sur la classe champig- Mons. 1641), 5 | experiments 1900; abstract | (Zur Entwickelungsgeschichte der | Equiseten und Rhizocarpen. Nova Acta | 315 Morphogenic influence of light and dark- ness, 285 Morren, E. (La lumiere et la vegetation. La Belgique Horticole. 13: 165. 1863), 300 Mucor, 29, 31 Myriophyllum, 27 spicatum, 217 Nabowick, A. (Wie die Fahigkeit der hé- heren Pflanzen zum anaeroben Wach- stum zu beweisen und zu demonstriren ist. Ber. d. Deut. Bot. Ges. 19: 222. 1901), 34 Naias major, 217 Narcissus, 214, 255, 256, 268, 269, 289 poeticus, 129 Tazetta, 128, 129 Neljubow, D. (Ueber die horizontale nu- tation der Stengel von Pisum sativum und einiger anderen Pflanzen. Beih. Bot. Centralb. 10: 128. 1901), 34 New York Botanical Garden, experiments in, 36 Nicotiana, 8, 274 rustica, 271 Noll, F, (Ueber das Etiolement. Separate a. d. Sitzungsber. d. Nied-Rhein. Gesell. f. Natur- u. Heilkunde z. Bonn. 1901), 33, 216, 284 (Ueber rotirenden Nutation an etio- lirenden Keimpflanzen, Bot. Zei- tung. 43: 664. 1885), 22 (Ueber die Einfluss der Lage auf die morphologische Ausbildung eini- ger Siphoneen. Arb.a. d. Bot. Inst. i. Wurzburg. 3: 466. 1888), 25 Nuphar luteum, 215 Nymphaea, 215 Observations, scope of, 35 Ocedogonium, 28 Onoclea sensibilis, 129, 130, 220, 278 Opuntia, 219, 247 Opuntia, 131, 132, 236, 237, 264 leucotriche, 237 Orchis ustulata, 17 Ornithogallum umbellatum, 130, 214, 255, 256 Osmunda cinnamomea, 132, 136, 220, 254, 278 Oxalis, 7, 259, 260 lastandra, 137, 141 violacea, 141, 143 Palladine, W. (Eiweissgehalt der griinen und etiolirten Blatter, Ber. d. Deut. Bot. Ges.g: 191. 1894), 23, 300, 304 (Ergriinen und Wachstum der etiolir- ten Blatter. Ber. d. Deut. Bot. Ges. Qs) 2205) 1691) 2 (Recherches sur la respiration des feuilles vertes et des feuilles étiolées. Rev. Gen. d. Bot. 5: 449. 1893), 2 316 Palladine (Transpiration als Ursache der Forminderung etiolirter Pflanzen. Ber. d. Deut. Bot. Ges. 8: 364. 1890), 25 Papaver, 271 somntferum, 10 Pastinaca sativa, 143,144, 243, 244,259,261, 286 Payer (Mem. sur la tendance des racines a fuir la lumiere, Compt. rend. d. 1. Acad. d: Sc. ls 1194.) 1542), 5 Peas, etiolation of, 1 Peltandra Virginica, 144-147, 215, 216, 220, 257, 259, 286, 296 Pericycle in etiolated stems, 251 Periderm, formation of on woody etio- lated stems. 249 Pertz, researches of, 305 Petiolate leaves, etiolation of, 257 Petunia, 275, 276 Pezizaceae, relation to light, 5 Pfeffer, on nature of etiolation (Pflanzen- physiologie. 2: 114. 1901), 284 Phaseolus, 26, 147-149, 224, 230, 246, 263, 265 multifiorus, 8, 9, 30, 226, 282 vulgare, 16 Phegopteris effusa, 34 Philotria Canadensis, 217, 218 Photo-epinasty, 14, 23 Photo-hyponasty, 14, 23 Phototonus, 18, 216 Phycomyces, 19, 31 Phyllocactus latifrons, 237 Phytolacca decandia, 149, 150, 243, 247; 249, 251, 263, 265, 267, 286 Pilobulus, 291 Pisum sativum, etiolation of, 7, 34 Pilobolus microsporus, 17, 30 PodophyMum peltatum, 150, 152, 220, 243, 244, 259, 261, 263, 265, 269 Poggioli, S. (Opuscules scientifiques de Bologne, 1: 9), 4 Polygonum, 9 cuspidatum, stems, 248 Polystichum acrostichotdes, 151-154, 220, 254, 278, 295, 297 Populus Simoni, 154-156, 239, 240, 241, 242, 246, 247, 249, 251, 268, 286, 295 Potentilla, 157, 261 reptans, 32 Potts, G. (Zur Physiologie des Dictyos- normal and_ etiolated telium mucoroides. Flora. gt : 281-347. 1902), 279 Prantl, R. (Ueber den Einfluss des Lichtes auf das Wachstum der Blatter. Arb. a. d. Bot. Inst. Wiirzburg. 1 : 371. 1873), 13, 282 Proserpinaca palustris, 217 Prunella grandiflora, 17 Pteris chrysocarpa, 9 longifolia, 157, 158, 220, 254, 2478 Pulmonaria acne 17 ei INDEX. Polygonum Fagopyrum, 227 Polypodium repens, 34 Quamasia (see Camassia), 214, 255, 306 Quercus, 115, 161-169, 189, 250, 251, 252 palustris, 158, 159, 230, 231, 239 rubra, 159-161, 230, 231, 239 Radish, 211 Rane, F. Wm. (Electro-horticulture with the incandescent lamp. Bull. No. 37. W. Virginia Exp. Station. 1894), 211, 293 on the effects of artificial illumination on plants, 275 Ranunculus Astaticus, 205 divaricatus, 27, 217 Raphanus, 19 Rate and mode of growth as affected by light and darkness, 304-309 Rauwenhoff, on etiolated stems, 248, 283 (Sur les causes des formes’ anormales des plantes. Ann. Sc. Nat. VI. 5: 267. 1878), 18 Ray, J. (Historia plantarum. 1: 15. also in imprint of 1693), 1 Re, F. (Saggio di nosologia vegetabile. p. 23- 1607), 2 : (Saggio teorico-pratico sulle malattie delle piante, p. 147, 1807), 4 Rennert, R. J. (Seeds and seedlings of Arisaema triphyllum and Arisaema Dra- ® contium. Bull. Torr. Club. 29: 37-54. 1902), 50, 221 Pheum, 167-169, 259, 260 Rhizomes, etiolation of, 216, 217 PRhododendron, 26 maximum, 210 Fehus, 169, 239, 240, 241 Richards, H. M., observations of, 33 LFicinus communis, 169, 170, 230, 231, 299 Ricome, M. H. (Action de la lumiere sur les plantes préablement étiolés. Rev, Gen. d. Bot. 14: 26, 72,1205 1002))5 33, 297, 298, 299 (Sur le développement des plantes étiolées ayant reverdi a la lumieére. Compt. Rend. 131: 1251. 1900), 33 Robinia pseudacacta, 29 Roots, etiolation of, 233-235 Rowlee, W. W. (Effect of the electric light upon the tissue of leaves. Proc. 19th Annual Meet. of the Soc. for Promo- tion of Agric. Science. Boston, Mass. pp. 50-58. 2 pls. 1898), 210 Fumex, 168, 170, 171, 219, 260 Rzentkowsky, T. (Untersuchung iiber die Entwickelung des etiolirten Phaseolus multifiorus. Mitth. a. d. Univ. z. War- shau ; abstract in Bot. Jahresber. 4: 745. 1876), 16, 304 1686; Sachs, investigations of, 39, 281, 282, 305 on etiolation, 275 INDEX. Sachs, on etiolation of seedlings, 245, 246 (Handbuch d. physiol. Bot. 1865; | see Lotos. Jan. 1859), 7 (Gesammelte Abhandlungen ueber Pflanzenphysiologie. 1: 229, 261, 1892), 10 (Physiology of ‘plants. English ed., P- 531. 1887), 234 (Vorlesungen ueber Pflanzenphysiol- ogie. 1865), 10 (Text-book of Botany. 2ded., p. 835), 15 (Ueber den Einfluss des Lichtes auf | die Bildung des Amylums in den Chlorophyllk6rnern. Bot. Zeitung. 20: 365. 1862), 7 (Uebersicht der Ergebnisse der neu- eren Untersuchungen ueber das Chlorophyll. Flora. 45: 129. 1862), 7 (Ueber den Einfluss des Tageslichtes auf Neubildung und Entfaltung ver- schiedener Pflanzenorgane. Bot. Zeitung. 21: Beil., p.31. 1863), 7, 223, 262, 272 (Wirkung farbigen Lichts auf Pflan- zen. Bot. Zeitung. 22: 353, 361, 369. 1864), 10 5 ‘ (Ueber die Wirkung der ultravioletten Strahlen auf die Bliithenbildung. Arb. a. d. Bot. Inst. i. Wiirzburg. Beye. 1057), 10. 272 (Ueber den Einfluss der Lufttempera- tur und des Tageslichts auf die stiindlichen und taglichen Aen- derungen des Langenwachstums (Streckung) der Internodien. Arb. a. d. Bot. Inst. i. Wiirzburg. 1: 99. 1872), I0 Salvia, 171, 269 argeniea, 22 Sansevierta, 215 Guitneensts, 171, 173, 255 Saponaria officinalis, 30 Saprolegnia, 29 Sarracenia, 260, 262, 286 purpurea, 173, 176 vartolaris, 177, 179 Saururus, 249, 266, 267 cernuus, 178-180, 217, 243, 249, 263 Schmitz, J. (Beitriage zur Anatomie und Physiologie der Schwamme. Linnaea. 17: 475. 1843), 5 Schober, on trichomes, 247 (Ueber das Wachstum der Pflanzen- haare an etiolirten Blatt- und Ach- senorganen. Zeitschr. f. Naturw. IV. 58: 4: 556. abstract in Bot. Centralb. 28: 39. 1886), 22 Schubeler (The effects of uninterrupted sunlight on plants. Nature. 21: 311. 1880), 207, 300 Schulz, N. (Ueber die Einwirkung des Lichtes auf die Keimungsfahigkeit der Sporen der Moose, Farne, und Schach- | Siemens, C. W. (On the 317 telhalme. 1901), 34 Schulzer von Muggenburg (Des alleleben- den Lichtes Einfluss aut? die Pilzwelt. Flora. 61: 119. 1878), 17 Beih. Bot. Centralbl. 11: 81. | Sczlla campanulata, 17 Scorzonera Hispanica, 9 _ Sedum dendroideum, 7 Seedlings, growth of in darkness, 230-235 Sempervivum assimile, 237 Haworthit, 7 Senebier (Hypothese pour expliquer l’eti- olement. Physiol.-vegetale. 4: 295- 308. 1800), 280 Senebier, researches of, 280 Senebier, J. (Observations sur les fleurs du quelques plantes élevées dans Vobscuritié. Mem. Physio-chim- iques. 2: 99. 1782), 270 (Mémoires physico-chimiques. 2: 51- UM@> 7s"), (Physiologie végétale. 4: 264-308. 1800), 2 influence of electric light upon vegetation and on certain physical principles involved. Nature. 21: 456. 1880; see also Proc. Roy. Soc. 30: 210-230), 208 Sieve tissue in etiolated stems, 251 Szlene pendula, 17 Stnaprs album, etiolation of, 3 Skototonus, 216 Smilax, 222, 224, 229, 246, 247, 267, 268 Beyrichit, 199, 200, 263, 264 Smith, J. E. (An Introduction to syste- matic and physiological botany. pp. 206; 207. 1807), 4 Solanum, 8, 12, 25, 221 tuberosum, 22, 30, 180, 181, 243 Soja hispida, 22 Sparaxis, 180, 214, 255 Spinach (see Sfznacta oleracea), 209, 211 Spinacia oleracea (see spinach), 209 Spiraea opulifolia, 16 Spirogyra, 13, 16 Sporangia, effect of etiolation on, 278 of fungi, relation to light, 279 Spores, effect of etiolation on, 278 Sporophores of fungi, relation to light, 279 Stachys lanata, 22 Stahl, E. (Ueber die Einfluss des Stan- dortes auf die Ausbildung der Laub- blatter. 1883), 22 Stameroff, K. (Zur Frage iiber den Ein- fluss des Lichtes auf das Wachstum der Pflanzen. Flora. 83: 135. 1897), 29 Stebler, F. G. (Untersuchungen iiber das Blattwachstum, Jahrb. f. wiss. Bot. 11: 47. 1878), 18 Stele, effect of etiolation on, 252 Stewart, drawings by, 174-176 Stigeoclonium tenue, 32 Stimulative influence of light, 288 318 INDEX. Stomata, development of on etiolated | Veronica sfectosa, 10 stems, 247 Vicia Faba, 7, 9, 23, 263 Strehl, R. (Untersuchungen iiber das | Vines, S. H. (The Influence of Light Lingenwachstum der Wurzel und des hypokotylen Glied. 1874), 14, 234 Succulents, effects of darkness on, 235-238 Taraxacum, 181 Taylor, A, drawings by, 37 Temperature at which observations were carried on, 36 Teodoresco, investigations of, 290, 291, 293, 294 - Teodoresco, on effect of light and dark- b ness on Vicza Kaba, 263 Teodoresco, E. C. (Action indirecte de la lumiere sur la tige et les feuilles. Rev. Gene (ds bObssur: §309,50720; 1899), 30 (Influence des différentes radiations lumineuses sur la form et la struc- ture des plantes. Ann. Sc. Nat. Bot. VIII. 10: 141-164. 1899), 30 Ternetz, C. (Protoplasmabewegungung Fruchtk6rperbildung bei Ascophanes carneus Pers. Jahrb. f. wiss. Bot. 35: Piyfars AN{919))) Bhi Tessier (Expériences propres a dével- loper les effets de la lumiére sur certaines plantes. Mém. l’Acad. d. Sc. Paris. p. 133- 1783), 3 Thaspium trifoliatum, 94 Thomas, J. (Anatomie comparée et ex- périmentale des feuilles souterrainnes. Rev. Gen. d. Bot. 12°: 394. 1900), 32 Tipularia, 215, 221, 268 untfolta, 181, 255, 256 Tomato, 211 Tragopon porrtfolius, 8 Trillium, 220, 269 erectum, 182, 243, 244, 257, 259 erythrocarpum, 131, 243, 244, 257, 259 Tritelia (see Milla) unzflora, 182-184, 214, 255, 256, 269 Triticum, 8, 12 Tropaeolum, 8, 9, 271, 274 MAJUS, 22 Tulasne (Fungi hypogaei) p. 2. Tulipa, 8, 214, 255, 256 Gesneriana, 271 patens, 185 sylvestris, 185 1852, 5 Uhlitzsch, P. G. (Untersuchungen iiber das Wachstum der Blattstiele. Ulothrix, 28 ‘ Urtica diotca, 12 Urticula pilulifera, 22 Vagnera stellata, 185, 186, 243, 263, 264, 267 Vaucheria sessilis, 16 Van Swinden (Account of Mees’ observa- tions. Journal de Physique. 6: 445. 1776. and 7: 112), 193, 2 1887), 22 | upon the Growth of Leaves. Arb. a. d. Bot. Inst. i. Wiirzburg. 2: 114. 1878), 19 (The Influence of Light upon the Growth of Unicellular Organs. Arb. a. d. Bot. Inst. i. Wiirzburg. 2: 133. 1878), 19 (On Epinasty and Hyponasty. Annals of Botany. 3: 415. 1889), 23 On Growth of Leaves in Darkness, 268 Vines, researches of, 305 Viola obliqua, 186, 187, 260, 269 rostrata, 187, 188, 243, 244, 249, 263 Vochting, H. (Organbildung im Pflan- zenreich. 2:66. 1884), 22 (Ueber der Knollenbildung. Botan. 1: Hit. 4. 1687)j22, (Ueber die Abhangigkeit des Laub- blattes von seiner Assimilations- thatigkeit. Bot. Zeitung, 49: 113. 1891), 22, 274 (Ueber den Einfluss des Lichtes auf die Gestaltung und Anlage der Bliithen. Jahrb. f. wiss. Bot. 25: 149, 1893), 22, 273 (Ueber die Bedeutung des Lichtes fiir die Gestaltung blattformiger Cac- teen. Zur Theorie der Blattsteil- ungen, Jahrb. f. wiss. Bot. 26: 438. 1894), 22, 238 Bibl. (Zur Physiologie der Knollenge wachse. Jahrb. f. wiss. Bot. 34: 1. 1900), 22 Vogel, A. (Beitrige zur Kenntniss der Verhaltnisses zwischen Licht und Vege- tation. Flora. 39: 385. 1856),6 - Vogt, C. (Ueber Abhangigkeit des Laub- blattes von seiner Assimilationsthatig- keit. Inaug. Diss., Erlangen. 1898), 30 Von Wolkoff, Measurements of etiolated plants, 115 Walz, J. W. (Ueber die Wirkung des Lichtes auf einige Processe des Pflan- zenlebens. Schrift. d. k. Neuruss. Univ. i. Odessa, 17: —, 1875; abstract in Bot. Jahresber: 3: 786. 1879)j0u5 Ward, H. M. (The Action of Light on Bacteria. Proc. Roy. Soc. 185: 961. 1895), 27 Water-etiolations, 216 Weiss, A. (Untersuchungen ueber die Zahlen und Gréssenverhaltnisse der Spalt6ffnungen. Jahrb. f. wiss. Bot. 4: 125. 1865-1866), 13 Wiesner, J. (Vorlaufige Mittheilung iiber den Einfluss des Lichtes auf Entste- hung und Zerest6rung des Chloro- phylls. Bot. Zeitung, 32: 116. 1874), 15 7 2a << “ ies OT ARES INDEX. Wiesner (Die heliotropischen Erschein- ungen im Pflanzenreiche. II: 7. 1880), 20 (Formanderungen von Pflanzen bei Cultur im absolut feuchten Raiume. undim Dunkeln. Ber. d. Deut. Bot. Ges.g: 46. 1891), 33, 238 (Photometrischen Untersuchungen auf Pflanzenphysiologischen Ge- biete. Sitzungsber. d.Kaiserl. Akad. d. Wiss. i. Wein. 102: Abth. 1. 1893), 2: (Untersuchungen ueber den Licht- genuss der Pflanzen in Arktischen 319 Gebiete. A. d. Sitzungsber. d. kaiserl. Akad. d. Wiss. i. Wien. tog: Abth. 1. May, 1900), 208 Woodwardia radicans, 188, 220, 254, 278 Woody perennials, etiolation of, 239-243 Xerophytes, etiolation of, 238 Zed, 230, 231, 267 Mays, 8, 12 Ziegebein, E. (Untersuchungen iiber den Athmung keimende Kartoffelknollen sowie anderer Pflanzen. Jahrb. f. wiss. Bot. 25: 563. 1893), 25 eed A, ‘ AL nee { by j i i) " en oe pa" at i, PRET |) i" J vay ae , oh Ol eae ay | ¥ 4 ft i af Ae : ; a7 rh yt ; 4 i ; j Ri oa a? aes ity Aes '. ee “vy. at a =, ~ — QK Tat M2 COp.e2 Forestry | . he eee Macdougal, Daniel Trembly ~ | The influence of light and _ darkness,upon growth and Pog development S = | ‘ Pires PORCH ot a : F 4 ' Boley yi t yt #o é 4, 4 4 $ ae . - st ST) zy? ve y Pers tr , hs ee ‘ sale “bac au ‘ aran Soman, eat AM ap RE L Heed i itte ‘ ‘ f v Ne te ? ‘ SSS byedttat . b ae i ry] . u D ‘ 4 ee ere | : the stwel oh H Esk rats Porseneneat Vesta its Bie UEID TH) eheeh ae be Bese ey ————— doth 5°93 © $ 7 Lo by ee fe ik i Cd ie } =a Rien aan shite r ? y Aes 4 ; Ww a Serenata) F ( ( 4 , i — Mook exten nee *f eset BOVE yy ovate 4 ————— Ay Caldreea |p ; pl £2 D pette t > peat Chat ease a4 5 7 2 , ‘ ‘ 4 ———— AN lta tities cE : ee Teron i = feel orator vad he 4 ——_— fort rte cea f ’ . r t 0 — : . pis ‘ oe F 5 ¥ — HavaN — ——— Ur agp dt ) fe ; ———— ; "at | Facesaruhe ‘ ' Vest apt ‘ ——ee He Teh i 4 Yr ie F i. 3 d Pare , Hi - were ESF t % . q b rap hatte 7 ra L N oii ’ ‘ < , s 3 . were ray H 4 ¥ ri Waly ¥ . ’ . w if thvete 7 mh : i. ‘ ‘ fre ty hey by he Ay Kibyetares : a otiet i Bra) i ; UTNE AEN : i NE NEMA CAR BUT Ae Re Oe tabi ie . ‘ ' 3 ; aun Pebiersie nse 4 F ‘ PUNEM OWS YEA: eA LOH aes Sheer tame tin cnod Ae ROSSRAR TEN ; Hh ‘ RHEL T PG TNT ERY | ak Onur : ; oy. - wir i TOO TAM Ue THEN ‘ (i Lo ay Rabati PhS Yoel oR ‘ : ; ‘ ACR Een PERN EET bretn ta 4 (pte Sia Ayn Rest ‘ viles SN 1 Pe tes . oe . é ! UNy Hey ety geagahis H " ‘ ( MRSS OF AEA MAN. ? ‘ Aus [huis Gah a beta : yt : f Rani eebes ree ‘ } ; } REWARDED) YOR VEE Mes Shy ‘ r } : STS binge reece i 5 f aS é LOR t 4 3 hes Desitee Waka. ens \ eae Wak : ij Wey ; Veet . Ue . Hh wpe? a sel Saas at enty a re Hare ; eis BEET ENT Pa ant ty Esa) i VPNs ‘ \ RTS MAE Rona Ga) ’ i 0 ‘ ‘ st (aa hen he , fs ‘i west ant hi ok P ; M tnt ve f 4 ae Slew oy seh) ‘ f \ 4 \ uke . ' f Seat X \ : } N ‘ “ xT : "bebe : Ny ? t ; . Ae 0 ‘ Av 3 ; ; H caver oO = Wu = n Oo a. Lu - <= 72) > <= a pee) S = <= c a 05 013 5 oa = 05