214 



MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 



A general examination of the results at hand may be made by a 

 recapitulation of the principal facts disclosed as to the etiolative and 

 other reactions exhibited by the different members and organs of the 

 bodies of the simpler and higher plants. 



Stems and main axes in general exhibit the greatest diversity of 

 behavior in the matter of growth in length and thickness, final ex- 

 tension and duration under etiolative conditions. The least devia- 

 tions from the normal occurs in species in which the main axis is 

 subterranean or is ordinarily shielded from the direct action of light. 

 Such plants usually send up leaves and flowers during the vegetative 

 season with die back periodically, to the underground or shaded por- 

 tion. The aerial organs thus produced, leaves, inflorescences and 

 branches, undergo etiolations that will be described below, and their 



altered development is not with- 

 out correlation effects upon the 

 axis of the plant not directly ex- 

 posed to the action of the rays. 



Effect of Etiolation on Bulbs, 

 Tubers, Corms and Rhizomes. — 

 In species in which the stem is 

 compressed and clothed with 

 scale-leaves in the form of a bulb 

 as in Allium (pp. 37,39), Ama- 

 ryllis (p. 40), Bowiea (p. 82), 

 Hemerocallis (p. 113), Hyacin- 

 thus{^. 117), Narcissus (p. 128), 

 Ornithogalltini (p. 120), ^cain- 

 assia (p. 87), Sfaraxis (p. 180), 

 Tritelia (p. 182), Tulifa\^^. 185) 

 and others of the same type but 

 little alteration ensues, except 

 that the bulbs or stems developed 

 as storage and propagative or- 

 gans at the end of the season 

 in the dark room are necessarily 

 smaller than the parent bulb 

 of the last growth in the open, by reason of the diminished amount 

 of material available for construction and the diminished surplus for 

 which storage is to be provided. The same is also generally true of 



Fig. 161. Aplectrum spicattim. A, 

 spent corm with young corm bearing a 

 leaf. B, resting corms, one of which was 

 formed under normal conditions, and the 

 other is attenuated from being formed in 

 darkness. 



