EUPHORBIACEAE (SPURGE FAMILY) 309 



short; anther-cells united. Pistillate calyx 3-8-parted, persistent. Capsule 

 3-lobed, bristly, separating into three 2-valved carpels. 



1. Tragia ramosa Torr. Ann. Lye. N. Y. 2: 245. 1826. Perennial, light 

 green, bristly with stinging hairs: stem erect, slender, often freely branched, 

 2-4 dm. high: leaves ovate-lanceolate to narrowly oblong, 1-4 cm. long, 

 serrate, cordate at base: calyx in pistillate flowers 5-lobed, 3-bracted; in stam- 

 inate 4-5-lobed, with 4-6 stamens: capsule depressed, bristly: seeds globose 

 orange, variegated. T. nepetaefolia ramosa. Colorado, eastward and south- 

 ward. 



4. EUPHORBIA L. SPURGE 



Monoecious herbs (ours), with alternate, opposite, or verticillate leaves 

 and cymose inflorescence. Flowers included in the 4-5-lobed involucres 

 which are terminal or in the axils; the involucral-lobes alternating with as 

 many fleshy glands, which are rounded and naked or bear petal-like or lunate 

 appendages. Sterile flowers lining the base of the involucre, each of a single 

 pediceled (or filament-bearing) stamen, joined to a minute bract (the supposed 

 rudimentary calyx). Fertile flowers solitary in the middle of the involucre, 

 soon protruded on a long pedicel. Capsule erect or nodding, 3-lobed, splitting 

 into three 2-valved carpels. 



Glands of the involucre with petal-like appendages (Chamaesyce'). 

 Leaves inequilateral and oblique at base. 

 Quite entire. 

 Seeds smooth. 



Appendages conspicuous; seeds terete . . . . 1. E. petaloidea. 

 Appendages small; seeds obtusely 4-angled . . 2. E. serpens. 



Seeds somewhat roughened. 



Glands broader than long, with fan-shaped appendages . 3. E. albomarginata. 

 Glands longer than broad, with crescent-shaped append- 

 ages '.- 4. E. Fendleri. 



Serrate or dentate. 

 Glabrous. 



Seeds pitted, faintly if at all rugose 5. E. serpyllifolia. 



Seeds rugose, not pitted . . . . . . 6. E. glyptosperma. 



Pubescent .......... 7. E. stictospora. 



Leaves with the two sides at the base similar. 



Appendages very large and conspicuous; leaves alternate . 8. E. marginata. 

 Appendages small; leaves opposite . . . . 9. E. hexagona. 



Glands of the involucre naked (without petal-like appendages). 

 Leaves opposite (Poinsettia). 



Ovate or orbicular-oblong, coarsely dentate . . . . 10. E. dentata. 



Oblong-linear or linear, nearly entire. 



Branched from the base, spreading . . . . . 11. E. Aliceae. 



Stem simple (at least below), erect . . . . . 12. E. cuphosperma. 



Leaves alternate or scattered (Tithymaltis). 

 Entire; glands semilunate. 



Stems tufted, low and stout 13. E. robusta. 



Stems few, taller and more slender ..... 14. E. montana. 



Serrate or dentate. 

 Annuals. 



Stems simple below ....... 15. E. arkansana. 



Stems branched from the decumbent base . . . 16. E. manca. 

 Biennial; stem branched from the base . . .17. E. commutata. 



1. Euphorbia petaloidea Engelm. Bot. Mex. Bound. Sury. 185. 1859. 

 Glabrous annual, low, freely branched, procumbent: leaves all similar, oblong- 

 linear, obtuse or retuse, attenuate to the scarcely oblique base: involucres 

 solitary, campanulate, lobes hairy beneath the glands which are about as long 

 as the lobes; appendages conspicuous, white, ovate or orbicular, entire or 

 crenulate: capsules globose-depressed: seeds cinereous, nearly smooth, oblong- 

 ovoid. Sandy plains; from the Rocky Mountains to the Mississippi river. 



2. Euphorbia serpens H. B. K. Nov. Gen. 2: 52. 1817. Glabrous or glau- 

 cescent annual, with filiform prostrate stems, often rooting: leaves round- 

 ovate, obtuse or cordate at base; stipules membranaceous, triangular: pe- 

 duncles longer than the petioles, solitary in the axils: glands salverform, 

 shorter than the lobes of the involucre; appendages minute, crenulate: cap- 



