BUPHORBIACE^J. (SPURGE FAMILY.) 327 



8 2. Leaves opposite, on short petioles, equal at base, with stipuiar glands : stems 

 diehotomously branched, erect: cymes terminal, involucres with 5 glands : seeds 

 tuberculate. 



10. E. hexagona, Nutt. Somewhat hairy: stem a foot or more high; 

 branches striate-angled : leaves linear-lanceolate, entire : involucre hairy with- 

 out and within : glands with a green ovate-triangular appendage twice their 

 length: capsule smooth: seeds ovate.— From Texas and Colorado to the 

 Upper Missouri. 



§ 3. Uppermost or floral leaves with conspicuous white petal-like margins, whorled 

 or opposite, the others scattered, equal at base, entire and sessile: involucres 

 5-lobed, collected in an umbel-like inflorescence. 



11. E. marginata, Pursh. Stem stout (2 to 3 feet high), erect, hairy : 

 leaves ovate or oblong: umbel with 3 dichotomous rays: glands of the 

 involucre with broad white appendages.— Prom Colorado to Kansas and 

 Nebraska. Cultivated and run wild in the Eastern States. 



It. Glands of the involucre without petaloid appendages. 

 § 4. Involucres in terminal clusters, 4 to 5-lobed, with few cup-shaped glands : 

 seed without a caruncle: leaves dentate, all but the lowest opposite, and 

 stipules glandular. 



12. E. deiltata, Michx. Erect or ascending, hairy : leaves ovate, lanceo- 

 late, or linear, petioled, coarsely toothed, upper ones often paler at the base : 

 involucres almost sessile, with 5 oblong dentate lobes, and one or more short- 

 stalked glands : seeds ovate-globular, slightly tubercled. — S. Colorado (Bran- 

 degee) and eastward to Illinois and Pennsylvania. 



§ 5. Involucres in a terminal dichotomous or commonly umbelliferous inflorescence, 

 4 or 5-lobed, with as many flat or convex entire or crescent-shaped glands : seeds 

 mostly carunculate: glabrous, with entire or serrulate scattered (except the 

 uppermost) leaves and no stipules. 



13. E. obtusata, Pursh. Erect : leaves oblong-spatulate, minutely serru- 

 late, smooth, obtuse ; upper ones cordate at base ; floral ones ovate, dilated : 

 umbel once or twice divided into 3 rays, then into 2 : involucre with naked 

 lobes and small stipitate glands: styles distinct and longer than the ovary, erect, 

 2-cleft to the middle : pod beset with long warts : seeds smooth and even: — 

 S. Colorado, and from Illinois to Virginia. 



14. E. dietyosperma, Pisch. & Meyer. Erect : leaves oblong- or ovate-' 

 spatulate, smooth, obtuse and obtusely serrate ; upper ones cordate at base : 

 umbels once or twice 3-forked, then 2-forked : involucre with nearly naked 

 lobes and small almost sessile glands : styles shorter than the ovary, spreading or 

 recurved : pod warty : seeds delicately reticulated. — Prom California and Ore- 

 gon to Texas, Kentucky, and Nebraska. 



15. E. montana, Engelm. Very glabrous and glaucous: stems leafy 

 and ascending : leaves rather thick, entire, ovate, obtuse ; floral ones orbiculate. 

 triangular : umbels repeatedly dichotomous : involucre roughish within, with 

 oblong-linear velvety lobes, and truncate, very shortly 2-horned glands : styles 

 very short, bifid : pod smooth : seeds superficially pitted. — From the Upper 

 Platte to New Mexico, Arizona, and southward. 



