720 EUPHORBIACEAE 
mm. long, sessile, bearing 3-4 crescent-shaped unappendaged glands prolonged into slen- 
der horns: capsules globose-ovoid, 3 mm. in diameter, glabrous, the lobes rounded : seeds. 
oblong or globose-oblong, barely 1.5 mm. long, terete, irregularly pitted. [Euphorbia 
commutata Engelm. ] 
On hillsides, chiefly along streams, Pennsylvania to Minnesota, Florida and Missouri. Spring and 
summer.—A form occurring in Florida, known as T. commutata, erécta (Norton) Small [Euphorbia com- 
mutata var. erecta Norton], is more erect in habit and has somewhat lanceolate leaf-blades. 
9. Tithymalus austrinus Small. Annual, bright green. Stem erect, 3-4 dm. tall, 
commonly branched near the base, each branch topped by a several-rayed umbel: rays 
dichotomous : leaves alternate; blades linear, 1-5 cm. long, entire, acute: bracts sub- 
tending the umbel a little broader than the leaf-blades: bracts of the rays opposite, del- 
toid : involucres 1-1.5 mm. long : glands crescent-shaped, with slender horn-like processes : 
capsules depressed, 3-3.5 mm. in diameter, glabrous, the lobes blunt: seeds ovoid, about 
2 mm. long, reticulated. 
In pine woods, western Florida. Summer. 
10. Tithymalus Péplus (L.) Hill. Annual, bright green, glabrous. Stem erect or 
assurgent, 1-3 dm. tall, simple or branched from the base or above and topped by a 3-5- 
rayed umbel: leaves alternate; blades oblong or obovate, 1-4 cm. long, obtuse or retuse, 
entire, more or less crisped, narrowed into slender petioles: bracts of the rays opposite, 
ovate or triangular-ovate, minutely apiculate, sessile: involucres campanulate, almost 
sessile in the axils of the bracts, 1-1.5 mm. high, bearing 4 crescent-shaped glands pro- 
duced into subulate horns: capsules globose-ovoid, 2-3 mm. in diameter, slightly nodding, 
smooth, the 3 lobes 2-keeled on the back : seeds oblong or oblong-ovoid, 1.5 mm. long, 
whitish, nearly terete, marked with 1-4 series of pits. [Euphorbia Peplus L.] 
In waste places, southern Canada to western New York, south to New Jersey, Pennsylvania, Ala- 
bama and in California. Naturalized from Europe. Spring to fall. 
11. Tithymalus Peplídion (Engelm.) Small Annual, glabrous. Stem simple 
below or usually branched at the base ; branches erect or ascending, 5-20 cm. long, topped 
by 3-rayed umbels : leaves alternate ; blades linear-spatulate or spatulate, 8-25 mm. long, 
entire, rounded or emarginate at the apex, at least near the base of the stem, narrowed into 
slender bases: rays forked : bracts of the rays ovate to rhombic-lanceolate, inequilateral : 
involucres turbinate, barely 1 mm. high, about as long as the peduncles or longer: glands 
transversely oblong, about 0.5 mm. wide, furnished with 2 horn-like appendages : capsules 
about 3 mm. broad, barely as high, lobes rounded, glabrous: seeds oblong, 1.3-1.5 mm. 
long, the faces deeply pitted. [Euphorbia Peplidion Engelm. ] 
In sandy and stony soil, Texas. 
12. Tithymalus tetrapórus (Engelm.) Small. Annual, glabrous. Stem erec 
simple or branched at the base, the branches 1-2 dm. long, topped by 3-rayed umbels an 
commonly branched below: leaves alternate; blades spatulate, cuneate or oblong, obtuse 
or notched at the apex, entire, narrowed into slender petioles or nearly sessile : rays forked : 
bracts ovate or triangular, apiculate, sessile : involucres campanulate, 1.5 mm. high, nearly 
sessile: glands transversely oblong, about 1 mm. broad, with 2 horn-like appendages of 
about the same length: capsules 3-lobed, 2-2.5 mm. broad, barely as high, glabrous, the 
angles obtuse : seeds broadly oblong, 1.3-1.4 mm. long, minutely pitted, gray. [Euphorbia 
tetrapora Engelm. } 
In sandy soil, the Indian Territory to Georgia and Texas. Spring. 
13. Tithymalus trichótomus (H.B.K.) Kl. & Garcke. Perennial, glabrous. Stem 
commonly branched at the base, more or less woody at the base, the branches erect or ascend- 
ing, 1-4 dm. tall, widely forking above: leaves numerous, rather approximate; blades 
thickish, cuneate to oblong, obtuse or acutish, 5-12 mm. long, minutely erose at maturity : 
rays trichotomous : involucres campanulate, 2 mm. high, sessile or nearly so : glands obren- 
iform, 1 mm. broad, yellow: capsules 3-lobed, 4 mm. wide, about j as high, the lobes 
rounded : seeds bial shoes, fully 1.5 mm. in diameter, white or pale gray, smooth. [Eu- 
phorbia trichotoma H.B.K.] 
In sand, southern peninsular Florida and the Keys. Also in the West Indies and eastern Mexico. 
14. Tithymalus Roemeriànus (Scheele) Small. Annual, glabrous. Stem erect, 2- 
4 dm. tall, terete, simple or branched below, topped by a 3-rayed umbel, the rays forg 
leaves alternate, remote ; blades thin, spatulate-obovate or prbicnlanapatejaa below, 0.5- 
2 cm. long, slightly emarginate, mucronate, serrulate near the apex, glaucescent beneath : 
bracts of the rays half-orbicular, crenate to about the middle : bracts subtending the umbel 
ovate, about 1.5-2 cm. long, obtuse: involucres campanulate, 1.5--2 mm. long: gan 
broad, furnished with 2 incurved horn-like processes: capsules subglobose, 3 mm. road, 
smooth ; lobes keeled: seeds oblong-ovoid, 1.6-1.8 mm. long, gray, irregularly pitted. 
[Euphorbia Roemeriana Scheele. ] 
In woods, southern Texas. 
