Capsella bursa-pastoris
Pfl.-Gatt., 85. 1792.
Plants mostly sparsely to densely pubescent, trichomes sessile, 3–5-rayed, stellate (base of plant often mixed with much longer, simple ones). Stems (0.2–)1–5(–7) dm. Basal leaves: petiole 0.5–4(–6) cm; blade oblong or oblanceolate, (0.5–)1.5–10(–15) cm × 2–25(–50) mm, base cuneate or attenuate, apex acute or acuminate. Cauline leaves: blade narrowly oblong, lanceolate, or linear, 1–5.5(–8) cm × 1–15(–20) mm, base sagittate, amplexicaul, or, rarely, auriculate. Fruiting pedicels usually straight, (0.3–)0.5–1.5(–2) cm, glabrous. Flowers: sepals green or reddish, 1.5–2 × 0.7–1 mm (margins membranous); petals (1.5–)2–4(–5) × 1–1.5 mm; filaments 1–2 mm; anthers to 0.5 mm. Fruits (0.3–)0.4–0.9(–1) cm × (2–)3–7(–9) mm, base cuneate, apex emarginate or truncate; valves each with subparallel lateral veins; style 0.2–0.7 mm. Seeds brown, 0.9–1.1 × 0.4–0.6 mm. 2n = 32.
Phenology: Flowering and fruiting Jan–Oct.
Habitat: Roadsides, gardens, fields, barren gravel, pastures, plantations, lawns, orchards, cultivated ground, waste areas, vineyards, mountain slopes
Elevation: 0-2800 m
Distribution
Greenland, Alta., B.C., Man., N.B., Nfld. and Labr., N.W.T., N.S., Nunavut, Ont., Que., Sask., Yukon, Ala., Alaska, Ariz., Ark., Calif., Colo., Conn., Del., D.C., Fla., Ga., Idaho, Ill., Ind., Iowa, Kans., Ky., La., Maine, Md., Mass., Mich., Minn., Miss., Mo., Mont., Nebr., Nev., N.H., N.J., N.Mex., N.Y., N.C., N.Dak., Ohio, Okla., Oreg., Pa., R.I., S.C., S.Dak., Tenn., Tex., Utah, Vt., Va., Wash., W.Va., Wis., Wyo., Europe, Asia, n Africa, introduced also in Mexico, West Indies, Central America, South America, Atlantic Islands, Pacific Islands, Australia.
Discussion
According to M. Coquillat (1951), Capsella bursa-pastoris is the second most common weed on earth, after Polygonum aviculare.
Selected References
None.