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 develop.ed long thin etiolated 

 shoots, which soon perished, e.vcept 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 Mimosa^ Phaseolus 

 and other species were used. Mimosa 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 

 chlorophyl.^" 



Amelung^^ repeated Sachs' experiment with etiolation of tips of 

 stems of Cucurbiia 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. 



GoebeP* 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 



^ijost, L. Ueber den Einfluss des Lichtes auf das Knospentreiben der Rothbuche. 

 Ber. d. Deut. Bot. Ges. 12 : 188. 1894. 



^^Jost, L. Ueber die Abhangigkeit des Laubblattes von seiner Assimilations- 

 thiitigkeit. Jahrb. f. Wiss. Bot. 27: 403. 1S95. 



^''Amelung. E. Ueber Etiolement. Flora, 78 : 204. 1894. 



^^Goebel, K. Ueber die Einwirkung des Lichtes auf die Gestaltung der Kakteen 

 und anderer Pdanze. Flora, 80 : 96. 1S95. 



