EUPHORBIACEAE 711 



bristles : involuci'es 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 transverse-wrinkled. 

 ^Euphorbia lata Engelm.] 



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



18. Cliamaesyce angusta (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 angtisfa Engelm.] 



In dry soil, Texas. Spring to fall. 



19. Chamaesyce revoliita (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 ram. broad, acute, entire, short-petioled : involucres sessile or on slender 

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

 erect : glands minute, broader tlian 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. [Euphorbm revohda 

 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, tlie 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. {_Eriphorbia polyddda Boiss.] 



In sandy soil, Texas. Spring and summer. 



21. Chamaesyce Nuttdllii (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 narroAved 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 f 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 

 globose-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 Porteri^na 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 refuse, entire, ciliolate, thick, veined above, trun- 

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



