Trifolium amoenum |
Trifolium beckwithii |
|
---|---|---|
showy Indian clover, two-fork clover |
Beckwith's clover |
|
Habit | Herbs annual, 45–65 cm, canescent. | Herbs perennial, 5–50 cm, glabrous. |
Stems | erect, branched from base and distally, or unbranched. |
erect or ascending, unbranched or several stems clumped from crown. |
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 narrowly ovate, lanceolate, or linear-lanceolate, 1–2 cm, margins entire or toothed, apex acute; petiole 0.5–20 cm; petiolules 1 mm; leaflets 3, blades usually rhombic, oblong, or elliptic, sometimes ovate, 2.5–5 × 0.6–2 cm, base cuneate, veins slightly thickened, margins setose-serrulate, apex obtuse or retuse, surfaces glaucous abaxially, glabrous. |
Inflorescences | terminal or axillary, 30–50-flowered, bluntly conic, ellipsoid, globose, or subglobose, 1.5–3 × 1.5–2.5 cm; involucres absent. |
terminal or axillary, 30–70+-flowered, globose or ovoid becoming subglobose, 1.5–4 × 1.8–3.3 cm, rachis prolonged beyond flowers, undivided or forked, often bearing sterile flower buds distally; involucres absent. |
Peduncles | 5–15 cm. |
straight, thick, 5–25 cm. |
Pedicels | absent; bracteoles cuplike, to 0.5 mm. |
strongly reflexed in fruit, 1–1.5 mm; bracteoles minute. |
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. |
11–14 mm, sweetly fragrant; calyx campanulate, gibbous, 4–6 mm, glabrous, veins 5, tube 2–3 mm, lobes unequal, narrowly triangular or subulate, orifice open; corolla light purplish, sometimes with pink tips, 10–13 mm, banner straight, obovate to broadly elliptic, 13–18 × 6–8 mm, apex rounded or retuse, apiculate. |
Legumes | obovoid, 4 mm. |
oblong, 5 mm. |
Seeds | 1, dark brown, ellipsoid, 2–3 mm, smooth. |
2–4, reddish brown, flattened globose, 1.5–2 mm, smooth. |
2n | = 48. |
|
Trifolium amoenum |
Trifolium beckwithii |
|
Phenology | Flowering Apr–May. | Flowering May–Jul. |
Habitat | Grassy slopes, swales, clay soils. | Moist, grassy meadows along streams. |
Elevation | 0–100 m. (0–300 ft.) | 1200–2000 m. (3900–6600 ft.) |
Distribution |
CA
|
CA; ID; MT; NV; OR; SD; UT; WA
|
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.) |
Disjunct populations of Trifolium beckwithii found in South Dakota are over 1200 km east of the nearest populations in Montana. The South Dakota populations appear to have been long-distance introductions from populations in northern California, based on molecular data (M. R. Duvall et al. 1999). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 11. | FNA vol. 11. |
Parent taxa | ||
Sibling taxa | ||
Name authority | Greene: Fl. Francisc., 27. (1891) | Brewer ex S. Watson: Proc. Amer. Acad. Arts 11: 128. (1876) |
Web links |