258 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 



organ (see Fig. 41). Although the utmost care was exercised in the 

 use of the lantern in the examination of etiolated specimens yet the 

 few minutes' exposure to which leaves of Caladiimi and Colocasia were 

 subjected during every week led to the formation of some chlorophyl 

 in the laminae, or rather it was to be seen in fully etiolated organs. 

 The possibility is not excluded that this substance had already been 

 formed in the buds previous to confinement in the dark chamber. 

 The fact remains however, that this species is able to construct 

 chlorophyl after a very limited illumination, and this statement may 

 be held true whether the green color was the result of the stimula- 

 tion from the faint artificial illumination in the dark room, or whether 

 it was formed as a result of the action of light upon the unopened 

 buds. A long succession of leaves was produced on plants kept in 

 the dark room, as has been previousl}^ described. The separate 

 members were of shorter duration than the normal organs although 

 furnished with functional stomata. Arodcs [Callii, p. 86) produced 

 etiolated leaves which shared the characteristics of Caladium in the 

 matter of the production of chlorophyl, and in the duration of these 

 organs. A succession of leaves was produced in darkness until the 

 corm was more or less nearly exhausted. In this species, however, 

 the laminae did not unroll and remained in a compact cylindrical 

 mass, held in an erect position, while the laminae of Caladiutn and 

 Colocasia were placed in various attitudes. Calla paliistris (p. 87) 

 developed petioles of a length slightly in excess of the normal in 

 etiolated specimens and the laminae were expanded to an extent that 

 approached the normal stature except that the margins were inrolled. 

 The cultural conditions provided were evidently not suitable for this 

 species and nothing may be deduced from its endurance, or failure 

 to produce more than one or two leaves in darkness. Leaves of 

 Canna grown in the dark chamber developed an excessively elon- 

 gated petiole, and a narrow lamina which was partially unrolled in 

 some instances, while in others it was fully expanded being held in 

 an erect position. A succession of these organs was produced for 

 four or five months until the material in the rootstocks was exhausted. 

 The sheathing basal portions of leaves of seedlings of Cocos nuci- 

 fera grown in darkness were elongated and more closely sheathing 

 than in the normal plantlets. The laminar portions were expanded 

 but were narrower and shorter than the normal, being held in an 

 erect position. Etiolated leaves were capable of an existence of a 



