113. Euphorbia peplus Linnaeus, Sp. Pl. 1: 456. 1753.
[F I W]
Petty spurge Petty spurge
Esula peplus (Linnaeus) Haworth; Galarhoeus peplus (Linnaeus) Haworth ex Rydberg; Tithymalus peplus (Linnaeus) Hill
Herbs, annual, with taproot. Stems erect, unbranched or branched, 5–30 cm, glabrous. Leaves: petiole 1–10 mm; blade obovate, oblong, or suborbiculate, 5–25 × 4–15 mm, base attenuate or cuneate, margins entire, apex obtuse, surfaces glabrous; venation pinnate, midvein prominent. Cyathial arrangement: terminal pleiochasial branches 3–5, usually 2–8 times 2-branched, 1st branching level rarely 3-furcate; pleiochasial bracts similar in shape to and slightly larger than distal leaves; dichasial bracts distinct, ovate to obovate, base obtuse, margins entire, apex obtuse, usually mucronate; axillary cymose branches 0–3. Cyathia: peduncle 0.4–1.1 mm. Involucre cupulate to slightly turbinate, 0.6–1.1 × 0.7–0.9 mm, glabrous; glands 4, elliptic, 0.2–0.3 × 0.5–0.6 mm; horns slightly convergent to divergent, 0.4–0.6 mm. Staminate flowers 10–15. Pistillate flowers: ovary glabrous; styles 0.1–0.2 mm, 2-fid. Capsules subglobose, 1.3–2 × 1.5–2.2 mm, slightly 3-lobed; cocci rounded, with 2 low longitudinal wings, smooth, glabrous; columella 1.1–1.3 mm. Seeds whitish or grayish, subovoid, 1–1.6 × 0.6–1 mm, abaxial faces regularly large-pitted (appearing almost alveolate), adaxial faces longitudinally sulcate; caruncle deciduous, conic, 0.2–0.5 × 0.2–0.7 mm.
Flowering and fruiting year-round. Edges of gardens, weedy flower beds, roadsides, waste places, open ground near forests; 0–1500 m; introduced; Alta., B.C., Man., N.B., Nfld. and Labr. (Nfld.), N.S., Ont., P.E.I., Que., Sask.; Ala., Ariz., Calif., Colo., Conn., Del., Idaho, Ill., Ind., Iowa, Ky., La., Maine, Md., Mass., Mich., Mont., Nev., N.H., N.J., N.Mex., N.Y., N.C., N.Dak., Ohio, Oreg., Pa., R.I., Tenn., Tex., Utah, Vt., Va., Wash., W.Va., Wis.; Europe, w Asia; introduced also in Mexico, West Indies, Bermuda, Central America, South America, Africa, Atlantic Islands, Indian Ocean Islands, Pacific Islands, Australia.