192 PLANT-LIFE 



flower, but as a general rule the flowers of the Angio- 

 sperms are hermaphrodite, as in the case of the Wall- 

 flower, already described — i.e., both sexes are united 

 in one flower, the stamens being the male and the 

 pistil the female. Stamens, pistil, corolla and calyx 

 are usually arranged in whorls, not spirals, on a much 

 abbreviated axis. It is in the Angiosperms, too, that 

 a new feature becomes firmly established; this is the 

 utilization of animals, principally insects, in the business 

 of pollination. The gaily coloured petals are not pro- 

 duced for idle show, in mere vanity; the nectar is not 

 secreted for sweetness' sake, nor is delicate perfume 

 diffused to pleasure the nostrils of man. These devices 

 exist for the allurement of insects, which, in taking the 

 bait and satisfying their lust for sweet things, become 

 unconscious pollinating agents. This relationship be- 

 tween insects and a vast number of flowers has un- 

 doubtedly led to great variety of floral structure. In 

 the Angiosperms fertilization affects the carpels forming 

 the pistil; they develop into the " fruit." The effects 

 may also extend beyond the carpels to the calyx, or 

 even to the floral receptacle, as in the case of the Straw- 

 berry, in which the receptacle becomes fleshy and is 

 commonly spoken of as the fruit. 



We find another contrast between the Gymnosperms 

 and the Angiosperms in the fact that the former are 

 much restricted in habitat and range, whereas the 

 latter have exhibited much elasticity in adaptation 

 to a great variety of conditions. One can hardly dis- 

 cover an environment where Angiosperms are not 

 to be found. If we wander over the tractless desert, 

 we find some species there. They have invaded pond, 



