472 



EUPHORBIACEAE. 



Vol. II. 



2. Tithymalus obtusatus (Pursh) Kl. 



& Garcke. Blunt-leaved Spurge. 



Fig. 2754. 



Euphorbia obtusata Pursh, Fl. Am. Sept. 606. 



1814. 

 Tithymalus obtusatus Kl. & Garcke, Abh. Akad. 



Ber. 1859 '■ 69- 



Annual, yellowish green, glabrous. Stem 

 slender, erect or assurgent, i°-2° high, strict, 

 branched above, topped by a 3-rayed umbel; 

 branches simple or forked ; leaves, except the 

 whorl, subtending the umbel, scattered, spatu- 

 late-oblong, obtuse, serrulate to below the 

 middle, sessile, the base slightly auricled; in- 

 volucres short-peduncled, i" long, bearing 4 

 stalked unappendaged glands ; capsule subglo- 

 bose, nearly 2" in diameter, with elongated 

 warts, the lobes rounded ; seeds lenticular, 

 oblong, or orbicular-oblong, dark brown, faintly 

 reticulated. 



In dry soil, Pennsylvania to Iowa, Kansas, 

 South Carolina and Texas. Warted spurge. 

 March-July. 



3. Tithymalus platyphyllus (L.) Hill. 

 Broad-leaved Spurge. Fig. 2755. 



Euphorbia plalyphylla L. Sp. PI. 460. 1753. 

 T. platyphyllus Hill, Hort. Kew. 172/4. 1768. 



Annual, glabrous or nearly so. Stems mostly 

 erect, slender, 4'-2o' high, terete, often reddish, 

 topped by a usually 5-rayed umbel; the branches 

 forked or umbellately branched; leaves except the 

 whorl at base of the umbel, scattered, oblong or 

 spatulate-oblong, io"-iS ' long, acute, serrulate, ses- 

 sile, the base slightly auricled; bracts triangular- 

 ovate or reniform, mucronate, often entire; invo- 

 lucres very thin, campanulate, nearly i" long, ses- 

 sile, bearing 4 sessile glands without appendages; 

 capsule subglobose, about 2" in diameter, with de- 

 pressed warts, the lobes rounded; seeds lenticular, 

 oblong or nearly orbicular, smooth, brown. 



Along the shores of the St. Lawrence River and the 

 Great Lakes, west to Manitoba. Naturalized from Eu- 

 rope. June-Sept. 



4. Tithymalus missouriensis (Norton) 



Small. Reticulate-seeded Spurge. 



Fig. 2756. 



E. arkansana missouriensis Norton, Rep. Mo. Bot. 



Gard. 11 : 103. 1900. 

 T. missouriensis Small, Fl. SE. U. S. 721. 1903. 



Annual, olive green, glabrous. Stem erect, 

 rather slender, 4'-is' high, topped by a compound 

 3-rayed umbel ; branches forked ; leaves, except 

 those subtending the umbel, scattered, spatulate 

 or oblong, 5"-il' long; obtuse, serrate to below 

 the middle, sessile, the upper slightly auricled at 

 the base ; bracts roundish or ovate, inequilateral, 

 small, serrate, cordate; involucres solitary in the 

 axils, less than i" long, with 4 oblong naked 

 nearly sessile glands; capsule depressed-globose, 

 li" in diameter, with elongated warts; seeds 

 ovoid, lenticular, reddish brown, finely but dis- 

 tinctly reticulated. 



Minnesota and Iowa to Montana, Washington, Ala- 

 bama and New Mexico. Included in our first edition 

 in Euphorbia dictyosperma F. & M., a far western 

 species. May-Aug. 



