9° 



PART I. — ORGANOGRAPHY. 



Wheat, Juncus acutiflorus and Hemp, all anemophilous, and the 

 three at the right, the pistils of the Tobacco, Foxglove and 

 Centradenia floribunda, all of which are pollinated by insect 

 agency. The enormous quantities of fine pollen produced by 

 such anemophilous plants as the Pines and Indian Corn, and the 

 great distances to which it is wafted, are facts familiar to every 

 observing mind. The Oaks, Poplars, Birches, Walnuts, Grasses, 

 Sedges, Plantains, Nettle and Hop are examples of plants of this 

 kind. 



Flowers which are cross-fertilized by the agency of insects are 

 called entomophilous. They include all those with showy calyx, 



Fig. 274. 



Fig. 575. 



Fig. 277. Fig. 2 



Fig. 276. 



Fig. 274. — Pistil of Wheat, showing a pair of long feathery stigmas. 



Fig. 275. — Pistil of Juncus acutiflorus, showing three elongated, hairy j All 

 stigmas. !■ anemoph- 



Fig. 276. — Pistil of Hemp, with two slender and much elongated, hairy | ilous. 

 or papillose stigmas. 



Fig. 277.— Pistil of Tobacco, with small, somewhat two-lobed, capitate ] 

 stigma. All 



FlG. 278. — Pistil of Digitalis, showing small, two-lobed stigma. J-entomoph- 



Fig. 279. — Pistil of Centradenia floribunda (enlarged), showing small pap- j ilous. 

 illose stigma. J 



corolla or bracts, all perfumed flowers, all nectar-bearing, and all 

 irregular flowers. The gay colors and perfumes are to attract 

 the attention of insects, the nectar to reward them for their ser- 

 vices, and the irregularities are adaptations of the flower to their 

 visits, the character of the adaptation being such as to render 

 cross-fertilization by their aid more certain. Bright colors and 

 perfume sometimes go together, and the flower offers a double 

 attraction to the insect visitor ; but more commonly highly 

 colored flowers are not odorous, or are but faintly so, and 

 conversely, highly odorous flowers are commonly not showy. 

 Flowers with corollas of some shade of red or blue are usually 



