Trifolium vesiculosum |
Trifolium nigrescens |
|
---|---|---|
arrow-leaf clover |
small white clover |
|
Habit | Herbs annual, 15–70 cm, glabrous. | Herbs annual, 10–60 cm, glabrous or glabrescent. |
Stems | erect or ascending, branched. |
usually erect or ascending, rarely prostrate, branched. |
Leaves | palmate; stipules linear-lanceolate, 1–3.5 cm, margins entire, apex subulate or setaceous; petiole 0.5–10 cm; petiolules 1 mm; leaflet 3, blades obovate to oblong, elliptic or lanceolate, 0.5–4 × 0.5–1.5 cm, base cuneate, veins prominent, thickened, margins spinulose-denticulate, apex apiculate, surfaces glabrous. |
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 or axillary, 50–100+-flowered, globose, ovoid, or oblong, 3–6 × 2–3.5 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 | 1–12 cm. |
1.5–4 cm. |
Pedicels | absent; bracteoles lanceolate, 6–7 mm, acuminate. |
reflexed in fruit, 3–6 mm; bracteoles narrowly oblanceolate, 3–6.5 mm. |
Flowers | 12–16 mm; calyx urceolate, not bilabiate, inflated in fruit, 6–10 mm, glabrous, veins 20–36, connected by transverse veins in fruit, tube 3–5 mm, lobes reflexed, subequal, subulate, as long as tube, orifice constricted; corolla white becoming pink, 12–15 mm, banner ovate, broadly clawed, striate, 12–15 × 2–4 mm, apex acute-acuminate. |
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 | ellipsoid, 2.5–2.5 mm, shorter than calyx. |
linear-oblong, 3–4.5 mm. |
Seeds | 2 or 3, brown, ovoid, 1–1.5 mm, roughened. |
1–5, yellow or pale or dark brown, oblong, 1 mm, smooth. |
2n | = 16. |
= 16. |
Trifolium vesiculosum |
Trifolium nigrescens |
|
Phenology | Flowering Apr–Jul. | Flowering Mar–Oct. |
Habitat | Fields, roadsides, forest openings. | Roadsides, lawns, fields, waste places. |
Elevation | 0–1000 m. (0–3300 ft.) | 0–200 m. (0–700 ft.) |
Distribution |
AL; AR; CA; FL; GA; LA; MA; MO; MS; OK; OR; SC; TX; VA; WA; s Europe; e Europe; w Asia [Introduced in North America]
|
AL; FL; GA; LA; MS; TN; TX; s Europe; w Asia; n Africa [Introduced in North America] |
Discussion | Trifolium vesiculosum was first introduced into cultivation in the United States in 1963 and is grown in southern and western states (J. D. Miller and H. D. Wells 1985). (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 | Savi: Fl. Pis. 2: 165. (1798) — (as vessiculosum) | Viviani: Fl. Ital. Fragm., 12, plate 13. (1808) |
Web links |
|