EUPHOKB1ACEAE 711 



bristles : involucres solitary in the axils, 1 mm. long, short-peduncled : glands 4, disk -like ; 

 appendages narrow, undulate : capsules subglobose, 2 mm. in diameter : seeds oblong, 1.5 

 mm. long, acutish at both ends, 4-angled, the faces inconspicuously trans verse- wrinkled. 

 [Euphorbia lata Engelm.] 



On plains and prairies, Kansas to Texas and New Mexico. Spring to fall. 



18. Chamaesyce angrista (Engelm. ) Small. Perennial, minutely pubescent. Stems 

 densely tufted, branched at the base, the branches erect or ascending, 1-4 dm. long, rather 

 rigid : leaf -blades linear or linear-lanceolate, 1-2.5 cm. long, acute, revolute, entire, firm, 

 sessile or nearly so : involucres turbinate to campanulate-turbinate, 1-1.5 mm. long, longer 

 than the peduncles : glands reniform, barely 0.5 mm. broad ; appendages white, fan -shaped, 

 dentate or erose fimbriate : capsules broader than high, 2.5-3 mm. broad, whitish: seeds 

 ovoid, 1.5-2 mm. long, transversely wrinkled. [Euphorbia angusta Engelm.] 



In dry soil, Texas. Spring to fall. 



19. Chamaesyce revoluta (Engelm.) Small. Annual, delicate, glabrous. Stems 

 erect, very slender, sometimes nearly filiform, 0.8-2 dm. tall, simple below, forking above, 

 the branches spreading or ascending : leaves few ; blades narrowly linear, 1-3 cm. long, 

 usually about 1 mm. broad, acute, entire, short-petioled : involucres sessile or on slender 

 peduncles about 1 mm. long, campanulate or turbinate-campanulate, less than 1 mm. high, 

 erect : glands minute, broader than long, purple ; appendages white or reddish, oblong or 

 ovate, obtuse, entire : capsules about 1 mm. long, rather sharply 3-angled : seeds oblong, 

 less than 1 mm. long, sharply 4-angled, the faces irregularly wrinkled. [Euphorbia revoluta 

 Engelm.] 



On hillsides, along the Rio Grande, Texas and northern Mexico. Summer. 



20. Chamaesyce polyclada (Boiss.) Small. Annual, glabrous. Stems branched 

 at the base, the branches numerous, decumbent or spreading, 0.5-1 dm. long, forked, 

 very slender : leaf-blades oblong or elliptic-oblong, 4-7 mm. long, obtuse and mucronu- 

 late, entire, rounded at the slightly oblique base, short-petioled : involucres turbinate, 

 about 1 mm. high, long-peduncled, the lobes triangular : glands minute ; appendages incon- 

 spicuous, pale or white, entire or 2-3-toothed : capsules fully 1.5 mm. long : seeds over 1 

 mm. long. [Euphorbia polyclada Boiss.] 



In sandy soil, Texas. Spring and summer. 



21. Chamaesyce Nuttallii (Engelm.) Small. Annual, bright green, glabrous. 

 Stems slender, erect or ascending, branched, 1-6 dm. high, the branches wiry : leaf- 

 blades mostly linear, 1-2.5 cm. long, mucronulate or truncate at the apex, often involute, 

 obtuse or narrowed at the base, petioled, usually curved, the midvein prominent ; stipules 

 lanceolate : involucres solitary in the axils, campanulate, less than 2 mm. long, long- 

 peduncled : glands 4, saucer-shaped ; appendages white, entire, oblong or ovate : capsules 

 about 2 mm. long : seeds ovoid, 1.5 mm. long, gray, 4-angled. [Euphorbia petaloidea var. 

 Nuttallii Engelm. ] 



On prairies, Kansas to Texas and Mexico. Spring to fall. 



22. Chamaesyce petaloidea ( Engelm. ) Small. Annual, pale green, glabrous. Stems 

 usually rather stout, erect, branched above, 1-6 dm. high : leaf-blades linear, oblong, or 

 linear-lanceolate, 1-2.5 cm. long, obtuse, usually flat, straight, entire, slender-petioled ; 

 stipules a fringe of bristles : involucres solitary in the axils, oblong-campanulate, 2 mm. 

 long : glands 4, wineglass-shaped, about as long as the lobes ; appendage white, reniform, 

 ovate or suborbicular, entire or undulate : peduncles as long as the involucres : capsules 

 glpbose-reniform, fully 2 mm. long : seeds oblong-ovoid, nearly 2 mm. long, ash-colored, 

 minutely pitted, nearly terete. [Euphorbia petaloidea Engelm.] 



On prairies, Iowa to Wyoming and Texas. Summer to fall. 



23. Chamaesyce buxifolia (Lam.) Small. Annual, glabrous. Stems erect or de- 

 cumbent, 2-5 dm. long, branching, purple, with long or short internodes : leaf-blades ovate 

 to broadly oblong or cuneate near the base of the stem, rather fleshy, 8-12 mm. long, ob- 

 tuse or acutish, involute, rounded or subcordate, nearly sessile : involucres campanulate, 

 about 1.5 mm. high, as long as the peduncles or shorter : glands transversely oblong, 0.5 

 mm. broad ; appendages consisting of mere whitish borders : capsules 2.5-3 mm. broad, 

 glabrous, the angles sharp: seeds globose-ovoid, 1-1.5 mm. long. [Euphorbia buxifolia 

 Lam.] 



In sand on the coast, peninsular Florida and the Keys. Also in tropical America. Spring to winter. 



24. Chamaesyce Porteriana Small. Annual, glabrous, or puberulent, bluish green. 

 Stems erect or ascending, sparingly branched, 1-2 dm. long : leaf -blades ovate, oval or 

 suborbicular, 5 10 mm. long, obtuse or retuse, entire, ciliolate, thick, veined above, trun- 

 cate or subcordate at the very oblique base, short-petioled : involucres hemispheric, nearly 



