Trifolium productum |
Trifolium nigrescens |
|
---|---|---|
elongated clover, productive clover, Shasta clover |
small white clover |
|
Habit | Herbs perennial, 15–45 cm, glabrous. | Herbs annual, 10–60 cm, glabrous or glabrescent. |
Stems | ± erect, loosely cespitose, branched. |
usually erect or ascending, rarely prostrate, branched. |
Leaves | basal and cauline, palmate; stipules ovate-lanceolate, 0.5–2 cm, margins usually entire, sometimes lobed, apex acute to acuminate; petiole 0.5–12 cm; petiolules 1 mm; leaflets 3, blades lanceolate or elliptic, 0.5–2 × 0.3–1.3 cm, base cuneate, veins prominent, margins serrate, apex acute, 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, 15–30-flowered, ellipsoid or conic, 1.5–2 × 1–3 cm, rachis prolonged beyond flowers, undivided or forked, often bearing sterile flower buds distally; 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 | 2–13 cm, slightly twisted apically. |
1.5–4 cm. |
Pedicels | strongly reflexed in fruit, 0.5 mm; bracteoles minute, lanceolate. |
reflexed in fruit, 3–6 mm; bracteoles narrowly oblanceolate, 3–6.5 mm. |
Flowers | 12–14 mm; calyx pink to purple, campanulate, 3–3.5 mm, glabrous, veins 10 (5 sometimes faint), tube 1.5–1.7 mm, lobes subequal, triangular-subulate, orifice open; corolla pink to deep purple, 12–14 mm, banner oblong, 12–14 × 4–5 mm, apex rounded or retuse. |
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 | obliquely ellipsoid, 5 mm. |
linear-oblong, 3–4.5 mm. |
Seeds | 1 or 2, brown, often purple-mottled, flattened ovoid, 2–3 mm, smooth. |
1–5, yellow or pale or dark brown, oblong, 1 mm, smooth. |
2n | = 16. |
= 16. |
Trifolium productum |
Trifolium nigrescens |
|
Phenology | Flowering May–Sep. | Flowering Mar–Oct. |
Habitat | Open coniferous woods, rocky places, stream banks, grassy meadows, near springs. | Roadsides, lawns, fields, waste places. |
Elevation | 1100–2800 m. (3600–9200 ft.) | 0–200 m. (0–700 ft.) |
Distribution |
CA; NV; OR
|
AL; FL; GA; LA; MS; TN; TX; s Europe; w Asia; n Africa [Introduced in North America] |
Discussion | Trifolium productum is morphologically most similar to T. kingii, from which it differs by its glabrous calyces and inflorescence rachises surpassing the flowers to 1.5 cm and apically forked (M. Zohary and D. Heller 1984). Trifolium productum is geographically isolated from T. kingii; the former is restricted to northern California, western Oregon, and western Nevada, while the latter is restricted to Utah and easternmost Nevada (J. M. Gillett 1972). (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 | ||
Synonyms | T. kingii subsp. productum, T. kingii var. productum | |
Name authority | Greene: Erythea 2: 181. (1894) | Viviani: Fl. Ital. Fragm., 12, plate 13. (1808) |
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