352 THE KINDS OF PLANTS 



of the world. The determination of the genera and species is difficult. 

 Euphorbia and Ricinus will sufficiently explain the flower structure for 

 the beginner. 



A. Flowers in a cup-like involucre, which imitates a perianth: 



flowers dioecious, without calyx or corolla 1. Euphorbia 



AA. Flowers, not in an involucre, but in a terminal panicle: 



flowers dioecious, calyx present, but no corolla 2. Ricinus 



1. EUPHORBIA. Spurge. 



Flowers monoecious inclosed in an involucre, which is 4-5-lobed and 

 often showy, resembling a perianth: staminate flowers each consisting of 

 a stamen jointed to filament-like pedicel, subtended by a minute bract, 

 attached on the inner surface of the involucre: the solitary pistillate flower, 

 standing at the bottom of the involucre, is at length protruded on a stalk: 

 capsule 3-lobed and 3-celled: styles 3, each 2-cleft: stigmas 6. Many of the 

 species are cultivated for ornamental purposes, as E. splendens, Crown of 

 Thorns; E. Cyparissias, Cypress spurge, common in old yards and about 

 cemeteries, where it has run wild. 



E. corollata, Linn. Flowering spurge. Perennial, 2-3 ft., slender- 

 branched: leaves mostly alternate, or the uppermost ones, or those on 

 the branches opposite, whorled, oval, rather thick, usually pale beneath: 

 flowering branches much forked: involucres terminal, or on peduncles, from 

 the forks of the branches, the lobes snowy white, appearing like petals with 

 oblong yellowish green glands at base of each. In dry or sandy soil, common. 

 July to October. 



E. maculata, Linn. Small plant, prostrate or spreading, the branches 

 slender and radiating, dark green, often dark red: leaves oblong-linear, 

 usually with red-brown spots in center: involucre minute, the corolla-like 

 appendages narrow, white or red. A common inconspicuous weed through- 

 out North America, except the extreme north. 



E. pulcherrima, Willd. Poinsettia. Floral leaves brilliant red and 

 appearing like flaming blossoms: flowers in a greenish involucre, with a 

 large yellow gland on summit. A Mexican species, well known as an 

 ornamental greenhouse plant. 



2. RICINUS. Castor-oil Plant. Figs. 313-316. 



Tall stately, perennial herb (annual North), with large, alternate, pal- 

 mately cleft leaves: flowers monoecious, apetalous, greenish, in terminal 

 racemes or panicled clusters, the pistillate flowers above the others; styles 

 large, reddish. 



R. communis, Linn. Castor bean. Palma Christi. Stem erect from 

 3-12 ft., somewhat branched: leaves very large, peltate, lobes acute, pointed, 

 toothed: seeds smooth, black, mottled or variegated with gray and brown. 

 Grown for medicinal and ornamental purposes. Tropical. There are many 

 forms in cultivation. 



