35 ECOLOGY. 



636. Male plants. Excepting some of the intermediate sizes, 

 one can usually select on sight the male and female plants. The 

 smaller ones which have a spathe are nearly all male and bear a 

 single leaf, though a few have two leaves. The male flowers are 

 also clustered at the base of the spadix, and are very much 

 reduced. Each flower consists only of stamens, and singularly 

 the stamens of each flower are joined into one compound stamen, 

 the anther-sacs forming rounded lobes at the end of the short 

 consolidated filaments. 



637. In some plants both male and female flowers occur on a 

 single spadix, the lower flowers being female, while the upper 

 ones are male. The larger plants are nearly all female, and many, 

 though not all, bear two leaves. In this dimorphism of the plant 

 there is a division of labor apportioned to the destiny and needs 

 of each, and in direct correspondence with the capacity to supply 

 nutriment. The staminate flowers, being short-lived, need com- 

 paratively a small amount of nutriment, and after the escape of 

 the pollen (dehiscence of the anthers) the spathe dies, while the 

 leaf remains green to assimilate food for growth of the fleshy short 

 stem (corm), where also is stored nutriment for the growth in the 

 autumn and spring when the leaf is dead. The female plants 

 have more work to do in providing for the growth of the embryo 

 and seed, in addition to the growth of the corm and next season's 

 flower. The smaller female j)lants thus sometimes exhaust them- 

 selves so in seed bearing that the corm becomes small, and the 

 following season the plant is reduced to a male one. 



638. The new roots each year arise from the upper part of the 

 corm. The stored substances in the base of the corm are used 

 in the early season's growth, and the old tissue sloughs off as the 

 new corm is formed above upon its remains. 



