Page:First course in biology (IA firstcourseinbio00bailrich).pdf/172

 The peculiar flowers of the pea tribes are explained in Figs. 187, 188.

, with one flower opened (a) to show the structure.



C, calyx, D, standard; W, wing; K, keel; T, stamen-tube; F, filament of tenth stamen; X, stigma; Y, style; O, ovary; the dotted lines at E show position of stamen tube, when pushed upward by insects. Enlarged .

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 chiefly tropical. The commonest wild representatives in the North 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 sepals. The common calla is a good example of this type of inflorescence.

Compositous Flowers.—The head (anthodium) or so-called "flower" of sunflower (Fig. 189), thistle, aster, dandelion, daisy, chrysanthemum, goldenrod, is composed of several or many little flowers, or florets. These