28 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 



simpler, and that the customary features of the formation of cork}' 

 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 Hcllehorus 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 likew^ise 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 zoo- 

 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 zoospores by Oedogoniimi 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 



58 Bonnier, G. Influence de la lumiere electrique continue sur la forme et la 

 structure des plantes. Rev. Gen. d. Bot. 7: 241, 289, 332, 407. 1895. 



s^MacDougal, D. T. Relation of the Growth of Foliage Leaves and the Chloro- 

 phjl Function. Jour. Linn. Soc. 31 : 526. 1896. 



'O" Darwin, F. Etiolation as a Phenomenon of Adaptation. Jour. Roy. Hort. Soc. 

 19: 345. 1896. 



^°> Klebs, G. Die Bedingungen der Fortpflanzung bei einigen Algen und Pilzen. 

 1896. 



