EUPHORBIACEAE 715 



1. Tricherostigma antisyphilitica (Zucc. ) Kl. & Garcke. Shrubby, glabrous. 

 Stems procumbent ; branches erect or ascending, 2-8 dm. tall, stout, simple or nearly so, 

 early leafless : leaves few, alternate ; blades linear, 10-18 mm. long, rigid, acute, recurved : 

 bracts scale-like, leathery, triangular : involucres sessile, or nearly so, constricted at the 

 base, 2-3 mm. high : glands transversely oblong, barely 1 mm. broad ; appendages white, 

 longer than the glands, undulate, somewhat cucullate : capsules globose-ovoid, 3-3.5 mm. 

 long, glabrous ; lobes rounded : seeds 2-2.5 mm. long, 4-sided, white, irregularly wrinkled. 



On gravelly or limestone hillsides along the Rio Grande, Texas and Mexico. 



26. DICHROFHYLLUM Kl. & Garcke. 



Annual caulescent herbs, with the erect stems often topped by a several-rayed umbel. 

 Leaves scattered below the umbel, thence opposite or whorled : blades often petal-like and 

 very showy, entire : stipules at the base of the petioles or leaf -blades, fugacious. Invo- 

 lucres campanulate, in rather dense cymes, pubescent without and within : lobes fimbriate. 

 Glands 5, peltate, somewhat concave, with white or pink petal-like appendages. Capsule 

 exserted, large, pubescent, the lobes rounded. Seeds narrowed upward, reticulated, with 

 caruncles. SPURGE. 

 Bracts of a linear type, reddish margined : involucral glands with reddish appendages. 



1. D. Ucolor. 

 Bracts of an oblong type, white margined : involucral glands with white appendages. 2. D. marginatum. 



1. Dichrophyllum bicolor (Engelm. & Gray) Kl. & Garcke. Stem 3-15 dm. tall, 

 usually topped by a 3-rayed simple or compound umbel : leaves scattered ; blades oblong 

 to oblong-lanceolate or the lower ones slightly broadest above the middle, all sessile, apic- 

 ulate : bracts linear or linear-spatulate, about as long as the leaves or longer : involucres 

 campanulate, 3.5-4 mm. high, hairy, longer than the peduncles : glands rather reniform, 

 1.5 mm. broad ; appendages white, reniform or fan-shaped, 3-4 mm. long, crenulate : cap- 

 sules woolly, becoming about 1 cm. broad, much depressed, 3-lobed : seeds ovoid, 5-6 mm. 

 long. [Euphorbia bicolor Engelm. & Gray.] 



On rich plains, Arkansas and the Indian Territory to Louisiana and Texas. Spring to fall. 



2. Dichrophyllum marginatum (Pursh ) Kl. & Garcke. Stem 3-9 dm. tall, somewhat 

 channeled, usually pilose, topped by a mostly 3-rayed umbel : leaves scattered ; blades 

 ovate to obovate, 2-9 cm. long, entire, sessile : rays of the umbel forked : bracts large, 

 white-margined : involucres campanulate, often clustered, 4 mm. long, usually pubescent, 

 bearing 5 glands subtended by white reniform appendages : capsules depressed-globose, 6 

 mm. in diameter, usually pubescent, the lobes rounded : seeds ovoid-globose, terete, about 

 4 mm. long, dark ash-colored, reticulate-tuberculate. [Euphorbia marginata Pursh.] 



In dry soil, Minnesota to Colorado and Texas. Introduced into waste places in the Central and 

 Atlantic States. Spring to fall. 



27. TITHYMALOFSIS Kl. & Garcke. 



Perennial herbs, with tough rootstocks and glabrous or pubescent foliage. Stems soli- 

 tary or tufted, topped by several-rayed umbels. Leaves alternate or scattered below the 

 umbels, thence opposite or whorled : blades entire, more or less leathery, inclined to be 

 revolute. Involucres sessile or peduncled, few and remote, or in rather close clusters and 

 numerous : lobes toothed or fimbriate. Glands sessile or stalked, with white pink or 

 rose petal-like appendages. Capsule exserted, sometimes conspicuously so, often broader 

 than high : lobes rounded. Seeds narrowed upward, more or less conspicuously punctate, 

 without caruncles. SPURGE. 



Leaves exceedingly numerous, approximate or imbricated. 1. T. polyphylla. 



Leaves relatively few, never imbricated. 



Stems normally underground ; branches of the inflorescence tufted ; all leaves 



or bracts opposite. 

 Glands of the involucre with inconspicuous margin-like appendages. 



Branches spreading or prostrate : leaf-blades fleshy. 2. T. Ipecacuanhae. 



Branches erect or ascending : leaf-blades thin. 3. T. gracilis. 



Glands of the involucre with conspicuous white appendages. 4. T, eriogonoides. 



Stems erect, topped by the umbel-like inflorescence, their leaves alternate. 



Stem-leaves reduced to scales. 5. T. mercurialina. 



Stem-leaves with normally expanded blades. 



A. Inflorescence of scattered long-peduncled involucres. 

 a. Involucres 2-4 mm. across the appendages. 



Stem-leaves with linear blades, fugacious. 6. T. Citrtisii. 



Stem-leaves with oblong or lanceolate blades, persistent. 



Appendages about as broad as the glands or narrower. 7. T. exserta. 



Appendages mainly much longer than the glands. 8. T. Joorii. 



