MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 243 



the stem perished, lateral buds near the base would awaken after a 

 resting period and carry out a second season's growth, when death 

 finally ensued from a concurrence of causes of which deficient 

 nutrition must have played an important part. 



Etiolation of Stems of Herbaceous Biennials and Perennials. — 

 The greatest amount of observation and experiment upon etiola- 

 tion has been made with herbaceous species in which the aerial 

 stems are sent up from subterranean axes containing more or less 

 storage material. The species examined by myself are as follows : 

 Aster divaricatus (p. 78), Botrychiuni obliquiim (p. 80), Brassica 

 camfestris (p. 84), Cyprifedmm montamim (p. loi), Delphinium 

 exaltaium (p. 102), Galium circaezans (p. 106), Hydrastis Canaden- 

 sis (p. T17), Hypopitys Hyfopitys (p. 119), Ipomcea Batatas (p. 120), 

 Lysimachia terrestris (p. 123), Pastinaca sativa (p. 143), Phytolacca 

 Decandra (p. 149), Podophyllum feltatum (p. 150), Saururus cernuus 

 (p. 179), Solammi tuberosum (p. 180), Trillium erythrocarpum (p. 

 181), T. crectum (p. 182), Vagnera stellata (p. 185) and Viola ros- 

 trata (p. 187). 



Hypopitys Hypopitys differs from the other species treated under 

 the above heading in the fact that it derives all of its construction 

 material from underground organs consisting of roots symbiotically 

 organized with mycorrhizal fungi, in consequence of which it has 

 undergone most sweeping morphological degenerations of the stelar 

 tracts and members of the shoot and root-systems. The degenera- 

 tion of the tissues has been accompanied by a loss of the capacity for 

 reaction to the direction of rays of light by phototropic movements. 

 Furthermore, it has been found that light is without appreciable effect 

 upon the shoot, the specimens grown in darkness not differing appre- 

 ciably from those in light. Some fungi were seen to make excessive 

 elongations of the sporophores in darkness, while others were unaf- 

 fected. It is difficult to assign an explanation for such divergence 

 of reaction among forms of supposedly similar physiological organ- 

 ization. 



A large number of herbaceous species of this group including 

 Aster divaricatus^ Cypripedimn montanum, Galium circaezans, 

 Ipomcea Batatas, Phytolacca Decandra, Saururus cernuus and 

 Vagnera stellata, do not make any excessive elongation of the 

 stems or shoots in darkness. Stems of these species developed 

 about the normal number of internodes in darkness, which did not 



