i8o 



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 



Fig. 140. Epidermis of etiolated petiole of Sauyurus cerniiiis. 



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 Sparaxis 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 



