324 EUPHORBIACE^E. (SPURGE FAMILY.) 



1. C. umbellata, Nutt. Stems leafy, 6 to 15 inches high : leaves oblong : 

 umbels few-flowered, corymbosely clustered at the summit of the stem : flowers 

 on slender pedicels, the white oblong erect or slightly spreading lobes about 

 equalling the green tube, which is continued conspicuously above the ovary : 

 fruit globular, 2 or 3 lines in diameter. In the Sierra Nevada of California 

 northward to Washington Territory and eastward across the continent. 



2. C. pallida, A. DC. Differing from the last in its narrower more glau- 

 cous and acuter leaves, which are linear to narrow] tj lanceolate, (or those upon the 

 main stem oblong), all acute or somewhat cuspidate : fruit ovoid, larger (3 to 4 

 lines long), sessile or on short stout pedicels. New Mexico and Colorado to 

 Oregon. 



ORDER 70. EUPHORBIACE^E. (SPURGE FAMILY.) 



Herbs (ours), with milky acrid juice, monoecious or dioecious com- 

 monly apetalous and often naked flowers, a free and usually 3-celled 

 ovary with (in ours) one pendulous ovule in each cell, and maturing into 

 a 3-celled elastically dehiscent capsule with crustaceous seeds. Stamens 

 one to many. Styles or stigmas as many or twice as many as the cells of 

 the ovary. Leaves mostly alternate and simple, often stipulate. 



# Staminate and pistillate flowers both with a perianth, without an involucre. 

 - Stamens erect in the bud. 



1. Tragia. Petals none. Calyx 3 to 8-parted. Flowers in racemes, terminal or opposite 



the leaves, pistillate at the base. Stamens 2 or 3. Style 3-parted. 



2. Argythamnia. Petals and sepals 5. Flowers in axillary spicate clusters, pistillate 



below. Stamens 5 to 15 in 1 to 3 whorls. Styles bifid. 

 *- -i- Stamens incurved in the bud. 



3. Croton. Flowers in terminal spike-like racemes. Erect and gray-scurfy. 



* # Flowers all without perianth, included in a cup-shaped calyx-like involucre. 



4. Euphorbia. Pistillate flower solitary, soon exserted : the staminate numerous, each 



of a single stamen. 



1. TRAGIA, Plumier. 



Staminate calyx 3 to 5-parted. Filaments short : anther-cells united. Pis- 

 tillate calyx 3 to 8-parted, persistent. Pod 3-lobed, bristly, separating into 

 three 2-valved carpels. Erect or climbing plants, pubescent or hispid, some- 

 times stinging, with mostly alternate stipulate leaves : the sterile flowers 

 above, the few fertile at the base, all with small bracts. 



1. T. nepetsefolia, Muller, var. ramosa, Miiller. Hirsute, erect, much 

 branched, 6 to 8 inches high : stem slender, at length flagelliform-elongated, 

 weak and somewhat turning : leaves triangular-ovate from a cordate base or 

 oftener lanceolate, gradually acuminate. Colorado and southward. 



2. ARGYTHAMNIA, P.Browne. 



Calyx valvate in the staminate flowers, imbricate in the pistillate. Petals 

 alternate with the calyx-lobes and with the lobes of the glandular disk. 



