CHAPTER XXII 



PARTICULAR FORMS OF FLOWERS 



289. General Forms. — Flowers vary wonderfully in 

 size, form, color, and in shapes of the different parts. These 

 variations are characteristic of the species or kind of plant. 

 The most variable part is the corolla. In many cases, the 

 disguises of the parts are so great as to puzzle botanists. 

 Some of the special forms, notably in the orchids, seem 

 to have arisen as a means of adapting 

 the flower to pollination by particular 

 kinds of insects. A few well-marked 

 forms are discussed below in order to 

 illustrate how they may differ among 

 themselves. 



290. When in doubt as to the parts 

 of any flower, look first for the pistils 

 and stamens. Pistils may be distin- 

 guished by the ovary or young seed- 

 case. Stamens may be distinguished 

 by the pollen. If there is but one 

 series in the floral envelope, the flower is assumed to lack the 



corolla: it is apetalous (273). The calyx, however, 

 in such cases, may look like a corolla, e.g., buck- 

 wheat, elm, sassafras, smartweed, knotweed. 

 (Fig. 210.) 



291. The parts of a flower usually have a 

 numerical relation to each other, — they are 

 oftenest in 3's or 5's or in multiples of these 

 numbers. The pistil is often an exception to this 

 order, however, although its compartments or 

 (143) 



240. Funnel form flower of 

 morning-glory. 



