140 



BEGINNERS' BOTANY 



The peculiar flowers of the pea tribes are explained in 

 Figs. 187, 188. 



Spathe Flowers. — In many plants, very simple (often 

 naked) flowers are borne in dense, more or less fleshy 

 spikes, and the spike is inclosed in or attended by a leaf, 

 sometimes corolla-like, known as a spathe. The spike of 

 flowers is technically known as a spadix. This type of 

 flower is characteristic of the great arum family, which is 



Fig. 187. — Flowers of the 

 Common Bean, with one 

 flower opened [a) 10 show 

 the structure. 



-Diagram of Alfalfa Flower 

 IN Section: 



C, calyx, Z>, standard; JF, wing; A", keel; T, sta- 

 men-tube; F, filament of tenth stamen; X, 

 stigma; K, style; C, ovary; the dotted lines at 

 E show position of stamen tube, when pushed 

 upward by insects. Enlarged. 



chiefly tropical. The commonest wild representatives are 

 Jack-in-the-pulpit, or Indian turnip, and skunk cabbage. In 

 the former the flowers are all diclinous and naked. In the 

 skunk cabbage all the flowers are perfect and have four se- 

 pals. The common calla is a good example of this type of 

 inflorescence. 



Composite Flowers. — The head (anthodium) or so- 

 called "flower" of sunflower (Fig. 189), thistle, aster, 

 dandelion, daisy, chrysanthemum, goldenrod, is com- 

 posed of several or many little Jlowers, or florets. These 



