TITHYMALOIDEiE. 79 



cells; the lobes in maturity separating from a central axis as a 1-celled 

 1-seeded carpel; this elastically dehiscent by two sutures and exposing 

 or ejecting the usually arilled or strophiolate seed. Ovules and seeds 

 pendulous. Embryo embedded in fleshy albumen; cotyledons flat. 



1. C ROTON, Linn. Pale scurfy or stellate hairy plants with alter- 

 nate exstipulate entire leaves and racemose, cymose or solitary unisexual 

 apetalous flowers. Staminate calyx 4 — 6 parted, slightly imbricate in 

 bud. Stamens 5 — 7, on a hairy receptacle; anthers inflexed in bud. 

 Pistillate calyx when present 5-parted. Ovary simple and 1-celled, or 

 2 — 3-lobed with as many cells; Btyles as many as the ovary -cells, simple 

 or once or twice forked. Seed grayish, smooth and shining. 



* Fruit 3-lobed; styles forked. 



1. C. Californicus, Mull. Arg. Suffrutescent, weak, decumbent or 

 prostrate: leafy branches erect, I ft. high; these and the foliage silvery - 

 canescenfc with a fine scurf and a minute stellate pubescence: leaves 

 narrowly oblong or elliptical, obtuse at each end, 1 — 2 in. long, on 

 petioles half as long: staminate flowers greenish, in short subsessile 

 racemes; calyx-lobes about 1 line long; filaments hairy: pistillate fl. 

 mostly solitary, on short pedicels; styles twice forked: capsule deeply 

 3-lobed, J£ in. thick: seed 2% lines long, with a small appressed carun- 

 cle. — Plentiful among the sandhills at San Erancisco and southward. 



* * Fruit of a single 1-seeded carpel, style simple. 



2. C. setigerus, Hook. A stout low annual with short but wide- 

 spread leafy branches, the heavy-scented herbage with a spreading 

 hispid and an appressed stellate pubescence : leaves ovoid or rhomboid, 

 }4 — 2 hi. long, on slender petioles, the upper crowded and appearing 

 opposite or whorled: staminate fl. few in corymb, long-pedicelled; calyx 

 with oblong obtuse segments a line long: pistillate fl. 1, 2 or 3 in an 

 axil; ovary and style densely pubescent: capsule and seed 2 lines long. 

 — Abundant in autumnal fields, mostly in the interior. 



2. EUPHORBIA, Linn. (Sptjrge). Herbs with milky juice, alter- 

 nate or opposite toothed or entire leaves, and inflorescence either 

 terminally clustered, or solitary in the forks of the many branches. 

 Both staminate and pistillate flowers within the same involucre; this 

 cup-shaped and like a calyx, the 4 or 5 lobes minute, usually alternating 

 with as many glands which have often a colored margin resembling a 

 petal. Staminate flowers many, of a single naked stamen jointed upon 

 a short pedicel which has often a minute bract at base. Pistillate flower 

 1, in the center of the involucre, pedicellate and soon exserted from it, 

 consisting of. a single 3-celled ovary, 3 forked styles and 6 stigmas each 

 2-lobed. Capsule 3-seeded. Seeds smooth, reticulate, rugose or pitted. 



