Trifolium amoenum |
Trifolium gracilentum |
|
---|---|---|
showy Indian clover, two-fork clover |
pin point clover, slender clover |
|
Habit | Herbs annual, 45–65 cm, canescent. | Herbs annual, 2–60 cm, glabrous. |
Stems | erect, branched from base and distally, or unbranched. |
erect or ascending, 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, 0.5–2.5 cm, membranous, margins entire or slightly serrate, apex long-acuminate; petiole 0.5–9 cm; petiolules to 0.5 mm; leaflets 3, blades obovate to obcordate, 0.5–2.5 × 0.2–1.5 cm, base cuneate, veins moderately thickened, margins setose-serrulate, apex rounded, shallowly retuse, surfaces 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, 10–25-flowered, globose to subglobose, 0.5–2 × 0.5–2 cm, rachis prolonged beyond flowers; involucres a narrow, membranous, dentate rim, to 0.5 mm. |
Peduncles | 5–15 cm. |
1–9 cm. |
Pedicels | absent; bracteoles cuplike, to 0.5 mm. |
becoming dramatically reflexed, 3–4 mm; bracteoles low, cuplike, membranous, to 0.5 mm. |
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. |
5–7.5 mm; calyx narrowly campanulate, 4.5–6.5 mm, glabrous, veins 10, tube 2–2.5 mm, lobes unequal, long-triangular, margins green or purple, orifice open; corolla white, pink, or purple, 5–8 mm, banner ovate, 5–8 × 3–4 mm, apex broadly rounded, retuse or apiculate. |
Legumes | obovoid, 4 mm. |
ovoid-ellipsoid, 4–6 mm. |
Seeds | 1, dark brown, ellipsoid, 2–3 mm, smooth. |
1 or 2, tan to brown, mitten-shaped, 1.1–1.5 mm, smooth. |
2n | = 16. |
|
Trifolium amoenum |
Trifolium gracilentum |
|
Phenology | Flowering Apr–May. | Flowering Mar–Jun. |
Habitat | Grassy slopes, swales, clay soils. | Open, grassy areas, gravelly ridges, roadsides, adobe slopes, moist places. |
Elevation | 0–100 m. (0–300 ft.) | 50–1200 m. (200–3900 ft.) |
Distribution |
CA
|
AZ; CA; NV; OR; WA; Mexico (Baja California)
|
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.) |
Abundance of Trifolium gracilentum increases in response to burns (J. M. DiTomaso et al. 1999). The record of Trifolium gracilentum from South Carolina is a waif. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 11. | FNA vol. 11. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | T. denudatum, T. exile, T. gracilentum var. exile, T. gracilentum var. inconspicuum, T. gracilentum var. reductum, T. inconspicuum | |
Name authority | Greene: Fl. Francisc., 27. (1891) | Torrey & A. Gray: Fl. N. Amer. 1: 316. (1838) |
Web links |