150 



FAMILIES OF FLOWERING PLANTS 



tlieir flowers; there are 5 sepals, the two lateral ones ranch larger than 

 the others, often brightly- colored, and known as wings: the petals are 

 3 or 5, somewhat united at their bases, the lowermost one often crested; 

 stamens 8, monadelphous or diadelphous (united in one or two sets); 

 ovary 2-celled, caijsular in fruit, the seeds ■v\ith a wart or protuberance 

 called a caruncle. The flowers vary greatly in color and in the mode 

 of arrangement, being white, yellow or purple, borne in close heads, in 

 spikes, racemes or cymes, the latter a spreading, flat-topped form of 

 inflorescence. 



In the northern States the milkworts are mostly small, inconspic- 

 uous plants, an exception being noted, however, in the case of the beau- 

 tiful little fringed polygala (P. paucifolia), often 

 known as flowering wintergreen. This has leaves 

 like the true wintergreen, with rose-purple, beau- 

 tifully fringed flowers. It also produces subter- 

 ranean flowers without petals, and these yield 

 most of the fruits. In the South, particularly 

 throughout the pine barrens, the milkworts are 

 among the most conspicuous of the flowering 

 plants, large masses of various species being con- 

 stantly met with. Among the more handsome 

 forms should be noted the various yellow flowered 

 species (P. cymosa, P. ramosa, and P. lutea), and 

 the large purple flowered P. grandifiora (see Fig. 

 130). 



Family Dichapetalaceae. Dichapetalum Fam- 

 ily. Consists of 3 genera and about 80 species, 

 widely distributed in the tropics, and particularly 

 abundant in Africa and Madagascar. They are 

 trees or shrubs with small flowers, similar in gen- 

 eral structure to those of the following family. 

 Family Euphorbiaceae. Spurge Family. Contains about 210 gen- 

 era and 4000 species, of wide distribution. They are herbs, shrubs or 

 trees; with monoecious or dioecious flowers, and an acid, often milky, 

 and frequently poisonous juice. The flowers are usually without pet- 

 als, and sometimes, as in Etuphorhia, without a calyx, the latter being 

 replaced by an involucre or whorl of leaves resembling a calyx. The 

 stamens vary greatly among the different genera; the ovary is usually 

 3-celled, with 3 styles, and the fruit a 3-lobed capsule; the latter gen- 

 erally serves as an easy means of identifying any member of the family. 

 The Euphorbiaceae are of interest in many ways; and following 

 the practice pre%dously adopted in these pages, we shall discuss the 

 important genera in the order of their tribal relationship. 



Fig. 130. Large-flowered 

 milkwort (Polygala grandi- 

 fiora), one-half natural size. 

 Original. 



