TRIPHVLLUM AND ArISAEMA DrACONTIUM 51 



the vigorous growth of .L tripJiylluin which was subjected to the 

 same conditions. 



On the other hand the small proportion of functional plumules 

 developed by seedlings of A. Dracoiitiuui and, in the cases in which 

 a leaf was produced, the great variations in shape, the small size, the 

 generalized form and venation, the delicacy of the lamina and the 

 weak development of wax upon it, the shortness of the petiole and 

 the frequent appearance of monstrosities, all are indications of de- 

 generation and lead to the conclusion that this seedling is losing 

 its power to produce a normal assimilating plumule. This con- 

 clusion is borne out by an examination of the internal structure. 

 The petioles of the smaller leaves of A. triphylhim show the same 

 arrangement of fibrovascular bundles as the largest of A. Dra- 

 contiiivi and a series of increasingly smaller plumules which may 

 easily be obtained from a number of seedlings shows a successively 

 more generalized development of fibrovascular system until in the 

 least developed system it becomes reduced to a mere rudiment. The 

 highly organized fibrovascular system of the hypocotyl, which is 

 of very little service to the seedling without a plumule and only a 

 weakly developed root system, is still retained and bears evidence 

 that the present type of seedling which brings a plumule to various 

 stages of imperfect development may be a degeneration from a con- 

 dition like that of the seedlings of A. tripliyllum with a plumule 

 normally functional. 



So far as has been observed this type of germination is of no 

 benefit to the seedlings. It does not seem to enable the corms to 

 escape from the danger which they incur of being torn up by 

 animals, for the development of the seedling without a strong 

 root system of course precludes any great downward pull upon 

 the corm by the contraction of its roots. Those plants of A. 

 Dracoiitmni which develop a leaf and correlated with this a 

 stronger root system have invariably been found buried deeper 

 than the plants w^hose plumule is not functional, for although in 

 the plumuleless seedlings there is no upwardly directed force to 

 bring the corm near the surface such as the plumule exerts in 

 forcing its way through the ground yet on account of the weak- 

 ness of the root system the tendency is such as to keep the corms 

 very near the depth at which the seeds germinated. The repres- 



