Trifolium amoenum |
Trifolium douglasii |
|
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showy Indian clover, two-fork clover |
Douglas' clover |
|
Habit | Herbs annual, 45–65 cm, canescent. | Herbs perennial, 20–75 cm, glabrous or slightly pilose. |
Stems | erect, branched from base and distally, or unbranched. |
erect, unbranched or sparsely 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 lanceolate to ovate, 1.5–6.5 cm, margins setose-serrulate or entire, apex acuminate; petiole 1.5–15 cm; petiolules 1 mm; leaflets 3, blades elliptic-oblanceolate to linear-elliptic, 3–9.5 × 0.5–1.6 cm, base cuneate, lateral veins prominent, recurved, dichotomously forked near margin, margins setose-denticulate to serrate, apex rounded or acute, surfaces glaucous, glabrous, sometimes sparsely pubescent abaxially. |
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, 30–50+-flowered, umbellate, globose to ovoid, 1.5–5 × 2–3.5 cm; involucres absent. |
Peduncles | 5–15 cm. |
3–12 cm. |
Pedicels | absent; bracteoles cuplike, to 0.5 mm. |
erect or slightly reflexed, to 0.2 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. |
14–16 mm; calyx campanulate, 6–9 mm, pilose, veins 15–20, tube 1.5–3 mm, lobes unequal, narrow, triangular or subulate, abaxial lobe straight, lateral and adaxial tortuous, recurved inwards around corolla, orifice open; corolla magenta, 12–16 mm, banner oblong, 12–16 × 4–6 mm, apex flared, acute or obtuse; ovaries glabrous or pubescent distally. |
Legumes | obovoid, 4 mm. |
ovoid, 3–4.5 mm. |
Seeds | 1, dark brown, ellipsoid, 2–3 mm, smooth. |
1 or 2, tan to brown, ovoid, 1–1.5 mm, slightly roughened. |
2n | = 16. |
|
Trifolium amoenum |
Trifolium douglasii |
|
Phenology | Flowering Apr–May. | Flowering Jun–Jul. |
Habitat | Grassy slopes, swales, clay soils. | Moist meadows, rich soils in prairies, stream bottoms and banks, openings in pine forests. |
Elevation | 0–100 m. (0–300 ft.) | 600–1500 m. (2000–4900 ft.) |
Distribution |
CA
|
ID; OR; 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.) |
Trifolium douglasii is rare throughout its range and has been impacted by agricultural practices (P. Camp et al. 2011). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 11. | FNA vol. 11. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | T. altissimum | |
Name authority | Greene: Fl. Francisc., 27. (1891) | House: Bot. Gaz. 41: 335. (1906) |
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