3 84 THE LILIALES 



a single species during their entire flight ; consequently the flower 

 by excluding the less intelligent and slothful insects is more cer- 

 tain of being properly crossed. The development of nectar and 

 also of odor glands are among the important variations that 

 appear in the evolution of the flower. It is chiefly by means of 

 the perfumes derived from the organs that the insect is directed 

 to the flowers. The coloration is also of service, when the insect 

 is near to the flower, thus supplementing the perfume glands by 

 directing him to the proper entrance. Some of the larger and 

 more brightly colored members of this and other orders appa- 

 rently depend entirely upon the attraction of their colors, while 

 other forms rely upon perfumes, the flowers being small and in- 

 conspicuous and often hidden. So we have reached a point in 

 the evolution of the flower where it presents a number of varia- 

 tions that are adapted and of benefit to special kinds of insects. 

 Insects have likewise varied and some have become of special use 

 to flowers owing to their peculiar form. In this way certain in- 

 sects and flowers have become dependent upon each other, and 

 as a result of their mutually beneficial variations, the flowering 

 plant and insects have greatly increased in numbers and exceeded 

 all other groups in the plant and animal kingdoms. 



(b) Other Forms of the Lily Order. This order comprises 

 an extensive series of plants that present nearly all the variations 

 that occur in the flower. At the bottom of the series is the Rush 

 family with grass-like stems and leaves (Fig. 288, A, B). The 

 flower has the same structure as noted in Erythronium, but the 

 perianth is composed of small scale-like leaves destitute of nectar 

 glands, and as you would expect, is anemophilous. The Bunch 

 flower family is a somewhat higher type. The flowers are ento- 

 mophilous, though the perianth is small and the carpels are often 

 but partially fused (Fig. 288, C, D). The flowers gain in con- 

 spicuousness, however, by being associated in compact inflores- 

 cences, but do not develop as a rule the bright colors characteris- 

 tic of large flowers. The family is represented by Tofieldia, 

 swamp pink (Helonias), blazing star (Chamaelirium) , Zygade- 

 nns, hellebore (Veratrum), bellwort (Uvularia), autumn crocus, 

 etc. The Lily of the Valley family is characterized by rather 



