246 PLANT FAMILIES: MONOCOTYLEDONS. 



401. 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 com- 

 pound stamen, the anther-sacs forming rounded lobes at the 

 end of the short consolidated filaments. 



402. The female plants require more food than the male 

 plants. 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 comparatively 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 w r ork 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 plants thus sometimes exhaust themselves so in 

 seed bearing that the corm becomes small, and the following 

 season the plant is reduced to a male one. 



403. Growth and death of the corm. The new roots each 

 year arise from the upper part of the corm. The stored sub- 

 stances 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. 



Material. Freshly collected plants should be used, the entire plant ; .small 

 ones as well as large ones. 



