Trifolium angustifolium |
Trifolium nigrescens |
|
---|---|---|
narrow-leaf clover, narrow-leaf crimson clover |
small white clover |
|
Habit | Herbs annual, 10–30 cm, appressed-pubescent. | Herbs annual, 10–60 cm, glabrous or glabrescent. |
Stems | erect, unbranched to sparsely branched. |
usually erect or ascending, rarely prostrate, branched. |
Leaves | palmate; stipules lanceolate to linear, 0.5–2.2 cm, margins entire, apex lanceolate-linear; petiole 2–3 cm; petiolules 1+ mm; leaflets 3, blades linear-lanceolate, 3–5 × 0.2–0.4 cm, base cuneate, veins fine, margins entire, apex acute, surfaces hairy. |
palmate; stipules triangular-lanceolate, 0.4–0.8 cm, margins entire, apex dark purple or reddish, sharply recurved, subulate; petiole 0.5–10 cm; petiolules 0.5 mm; leaflets 3, blades obovate or obtriangular, 0.5–2.5 × 0.3–2.5 cm, base cuneate, veins fine, margins denticulate, apex rounded to emarginate, surfaces glabrous. |
Inflorescences | terminal, 25–75-flowered, spicate, cylindric or conic, 3–8 × 1.5–2 cm; involucres absent. |
axillary or terminal, 15–50-flowered, globose, 1–1.8 × 1–1.8 cm; involucres a narrow rim, to 0.2 mm. |
Peduncles | 1–2.2 cm. |
1.5–4 cm. |
Pedicels | erect, 0.5 mm; bracteoles absent. |
reflexed in fruit, 3–6 mm; bracteoles narrowly oblanceolate, 3–6.5 mm. |
Flowers | 10–13 mm; calyx tubular, 8–13 mm, tuberculate with appressed, stiff hairs, veins 10, tube 3–5 mm, lobes unequal, abaxial lobes longest, subulate-setaceous, spreading stellate in fruit, orifice closed by bilabiate callosities, hairy; corolla usually pale pink or purple, rarely white, 9–12 mm, banner ovate-elliptic, 9–12 × 2–2.5 mm, apex notched. |
6.5–9 mm; calyx oblong, 3–5 mm, glabrous or pubescent, veins 5–10, tube 1–2.5 mm, lobes ± equal or unequal, triangular-lanceolate, recurved in fruit, margins green or purple, apex acute to acuminate, orifice open; corolla pink or white, 6–9 mm, banner obovate-oblong, 6–9 × 1–2 mm, apex acute to emarginate. |
Legumes | ovoid, leathery distally, transversely dehiscent, 2.2–2.5 mm. |
linear-oblong, 3–4.5 mm. |
Seeds | 1, light brown or yellow, ovoid, 1.6–2 mm, smooth, glossy. |
1–5, yellow or pale or dark brown, oblong, 1 mm, smooth. |
2n | = 14, 16. |
= 16. |
Trifolium angustifolium |
Trifolium nigrescens |
|
Phenology | Flowering Mar–Apr. | Flowering Mar–Oct. |
Habitat | Waste places, fields, meadows. | Roadsides, lawns, fields, waste places. |
Elevation | 0–1000 m. (0–3300 ft.) | 0–200 m. (0–700 ft.) |
Distribution |
AL; CA; OR; SC; Europe; w Asia; n Africa; Atlantic Islands (Canary Islands) [Introduced in North America; introduced also in s South America (Chile, Uruguay), s Africa, Pacific Islands (New Zealand), Australia]
|
AL; FL; GA; LA; MS; TN; TX; s Europe; w Asia; n Africa [Introduced in North America] |
Discussion | Trifolium angustifolium is spreading rapidly in west-central California and is weedy in many regions globally (R. P. Randall 2002). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Trifolium nigrescens was shown, using molecular markers, to consist of three subspecies and to hybridize readily with T. repens (W. M. Williams et al. 2001). It was first introduced as a potential crop species in the early 1950s and is cultivated widely in the southeastern United States as a forage crop and as a nitrogen source in roadside grass plantings (C. S. Hoveland 1960). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 11. | FNA vol. 11. |
Parent taxa | Fabaceae > subfam. Faboideae > Trifolium | Fabaceae > subfam. Faboideae > Trifolium |
Sibling taxa | ||
Name authority | Linnaeus: Sp. Pl. 2: 769. (1753) | Viviani: Fl. Ital. Fragm., 12, plate 13. (1808) |
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