454 EUPHOKBIACE^. (SPURGE FAMILY.) 



red spot or red margins ; stipules triangular ; peduncles longer than the peti- 

 oles, collected in loose leafy terminal cymes; appendages entire, \a,xg%v and 

 white, or smaller and sometimes red ; pod glabrous, obtuseli/ angled ; seeds ovate, 

 obtiiseli] angled, ivrinkled and tubercled (^" long), blackish. (E. hypericifolia 

 of Man., not L.) — Common throughout the U. 8. east of the plains. 



§ 2. ZYGOPHYLLIDIUM. Leaves opposite, on short petioles, not oblique, 

 with stipular glands ; stems dichotomously branched, erect; cymes terminal; 

 involucres with 5 glands ; seeds tuberculate. 



10. E. hexagona, Xutt. Somewhat hairy (1° high or more) ; branches 

 striate-angled ; leaves linear-lanceolate, entire ; involucre hairy without and 

 within ; glands with green ovate-triangular appendages twice their length ; 

 capsule smooth; seeds ovate. — Iowa to Tex., west to Col. and Montana. 



§ 3. PETALOMA. Uppermost leaves with conspicuous white petal-like mar- 

 gins, whorled or opposite, the others scattered ; erect annuals, with leaves equal 

 at base and entire, and ivith lanceolate deciduous stipules ; involucres 5-lobed, 

 in an umbel-like inflorescence. 



11. E. marginata, Tursh. Stem stout (2-3° high), erect, hairy ; leaves 

 sessile, ovate or oblong, acute ; umbel with 3 dichotomous rays ; glands of the 

 involucre with broad white appendages. — Minn, to Mo., west to Col., also 

 spreading eastward to Ohio, and frequently escaped from gardens, where it is 

 often cultivated for its showy broadly white-margined floral leaves. 



§ 4. TITHYMALOPSIS. Only the uppermost leaves whorled or opposite ; erect 

 perennials, with entire leaves equal at base ; stipules none ; involucres mostly .5- 

 lobed, in the forks of the branches and terminal ; inflorescence umbelliforni. 



12. E. COrollata, L. Glabrous or sometimes sparingly hairy (2-3° 

 high); leaves ovate, lanceolate, or linear, entire, obtuse; umbel 5- {3-7-) 

 forked, and the forks again 2-3- (or rarely 5-) forked; involucres long-pe- 

 duncled, with showy white appendages (appearing like petals), the lobes mi- 

 nute and incurved; pod slender-pedicelled, smooth; seeds thick {V long or 

 more), ash-colored, slightly uneven. — Rich or sandy soil, N. Y. and N.J. to 

 Fla., west to ]\Iinn. and La., also adventive in Mass. July -Oct. 



B. Glands of the involucre icithout petaloid appendages. 



§ 5. POINSETTIA. Involucres in terminal clusters, 4 -5-lobed, icith few {or 

 often solitary) cup-shaped glands ; erect annuals, ivith variable, entire, den- 

 tate, or sinuate leaves, all or only the upper ones opposite; the uppermosi 

 often colored, especially at base ; stipules small and glandidar. 



13. E. dentata, ^lichx. Erect or ascending, hairy (1° high); leaves 

 ovate, lanceolate, or linear, petioled, coarsely toothed (1 -2' long), o?i/// the 

 lowest alternate, the upper often paler at base ; involucres almost sessile, with 

 5 oblong dentate lobes, and one or sometimes more short-stalked glands; 

 seeds ovate-globular, slightly tubercled. — Rich soil, Penn. to Tenn., Iowa, 

 E. Kan., and southward. July -Sept. 



14. E. heteroph;^lla, L. Erect (l-3° high), glabrous; leaves alter- 

 nate, petioled, ovate-fidille-shaped and sinuate-toothed, or lanceolate or linear 

 and entire, often only those of the branches linear; the upper usually with a 



