Trifolium amoenum |
Trifolium barbigerum |
|
---|---|---|
showy Indian clover, two-fork clover |
bearded clover |
|
Habit | Herbs annual, 45–65 cm, canescent. | Herbs annual, 7–20 cm, puberulent or glabrous. |
Stems | erect, branched from base and distally, or unbranched. |
decumbent or erect, branched. |
Leaves | palmate; stipules ovate-oblong, 0.5–1.8 cm, margins entire, toothed, or irregularly lobed, apex acuminate; petiole 0.5–10 cm; petiolules to 1 mm; leaflets 3, blades broadly obovate or elliptic, 1.7–3.3 × 1.1–2 cm, base cuneate, veins fine, margins entire or denticulate, apex rounded, obtuse, or retuse, surfaces pilose, abaxial less so. |
palmate; stipules ovate-lanceolate, 0.5–1.1 cm, margins toothed or lacerate, apex acute-acuminate; petiole 1–10 cm; petiolules to 0.5 mm; leaflets 3, blades oblanceolate or obovate, 1.5–2.5 × 0.4–0.7 cm, base cuneate, veins fine, thickened distally, margins ± serrate or entire, apex rounded or retuse, surfaces pubescent or glabrous. |
Inflorescences | terminal or axillary, 30–50-flowered, bluntly conic, ellipsoid, globose, or subglobose, 1.5–3 × 1.5–2.5 cm; involucres absent. |
axillary or terminal, 5–20-flowered, subglobose or globose, 0.6–1.5 × 1–1.5 cm; involucres bowl-shaped, 5–15 mm, lobes 6–10, sharply setaceous-toothed, sinuses shallow. |
Peduncles | 5–15 cm. |
5–10 cm. |
Pedicels | absent; bracteoles cuplike, to 0.5 mm. |
straight, 0.2 mm; bracteoles absent. |
Flowers | 13–16 mm; calyx tubular, 9–12 mm, pubescent, veins 20–30, tube 3 mm, lobes nearly equal, appearing rigidly erect, linear-setaceous, plumose, sinuses acute, orifice open; corolla white to pink with purple tips, 12–16 mm, banner ovate-oblong, 12–15 × 4 mm, apex broadly rounded, emarginate. |
4–6 mm; calyx campanulate, 5–9 mm, usually pubescent, rarely glabrous, veins 5, tube 2–3 mm, lobes ± equal, setaceous, often exceeding banner, orifice open; corolla usually lavender to purple, usually with white tips, rarely wholly white, 5–8 mm, banner broadly oblong, proximally inflated in fruit, distally narrowed into twisted tip, 6–8 × 6–8 mm, apex broadly acute. |
Legumes | obovoid, 4 mm. |
ovoid-ellipsoid, 2–3 mm. |
Seeds | 1, dark brown, ellipsoid, 2–3 mm, smooth. |
1 or 2, brown, ellipsoid to subglobose, 1–1.5 mm, slightly roughened. |
2n | = 16. |
|
Trifolium amoenum |
Trifolium barbigerum |
|
Phenology | Flowering Apr–May. | Flowering Apr–Jun. |
Habitat | Grassy slopes, swales, clay soils. | Vernal pools, stream banks, meadows, lawns. |
Elevation | 0–100 m. (0–300 ft.) | 0–1300 m. (0–4300 ft.) |
Distribution |
CA
|
CA; OR
|
Discussion | Trifolium amoenum was considered extinct (J. P. Smith Jr. 1984) but was rediscovered in 1993 (P. G. Connors 1994). Specimens of T. amoenum are known from Marin, Napa, San Mateo, Solano, and Sonoma counties; it appears to be extant in only single populations in each of Marin and Solano counties. Allozyme studies of the two known populations revealed fixed genetic differences between them (E. E. Knapp and Connors 1999). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Trifolium barbigerum is relatively common and widespread in California, and extends northward into Coos, Curry, and Jackson counties in Oregon. It is morphologically similar to T. physanthum of Chile, to which it is a sister species in phylogenetic studies (N. W. Ellison et al. 2006). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 11. | FNA vol. 11. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | T. minutissimum | |
Name authority | Greene: Fl. Francisc., 27. (1891) | Torrey in War Department [U.S.]: Pacif. Railr. Rep. 4(5): 79. (1857) |
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