Trifolium amoenum |
Trifolium monanthum |
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showy Indian clover, two-fork clover |
carpet clover, mountain carpet clover |
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Habit | Herbs annual, 45–65 cm, canescent. | Herbs perennial, 3–22 cm, glabrous or hairy, often mat-forming. | ||||||||||||
Stems | erect, branched from base and distally, or unbranched. |
decumbent to ascending, much-branched. |
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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 to lanceolate, 0.3–1.2 cm, margins entire, serrate, or slightly lacerate, apex acute to acuminate; petiole 1–4.5 cm; petiolules 0.1–0.5 mm; leaflets 3, blades obovate, oblanceolate, or elliptic, 0.3–2 × 0.2–0.5 cm, base cuneate, veins prominent, margins ± dentate, serrate, or setose, apex acute, rounded, or retuse, surfaces glabrous or slightly villous. |
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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, 1–9-flowered, solitary or subglobose, 1–1.6 × 0.3–1.2 cm; involucres campanulate, 2–5 mm, incised nearly to base, lobes 2–8, lanceolate. |
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Peduncles | 5–15 cm. |
0.5–2 cm. |
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Pedicels | absent; bracteoles cuplike, to 0.5 mm. |
erect, 1 mm; bracteoles absent. |
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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. |
10–16 mm; calyx tubular, 2–10 mm, glabrous or pubescent, veins 10, tube 4–7 mm, lobes equal, triangular-subulate, orifice open; corolla white, pink, or lavender, keel petals usually purple-spotted, 8–16 mm, banner oblong, 8–13 × 2–5 mm, apex emarginate. |
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Legumes | obovoid, 4 mm. |
oblong, 2–4 mm. |
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Seeds | 1, dark brown, ellipsoid, 2–3 mm, smooth. |
1 or 2, brown, mottled, mitten-shaped, 1–2 mm, dull. |
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2n | = 16. |
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Trifolium amoenum |
Trifolium monanthum |
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Phenology | Flowering Apr–May. | |||||||||||||
Habitat | Grassy slopes, swales, clay soils. | |||||||||||||
Elevation | 0–100 m. (0–300 ft.) | |||||||||||||
Distribution |
CA
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w United States; nw Mexico
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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.) |
Subspecies 4 (4 in the flora). Morphological intergradation among subspecies of Trifolium monanthum may be indicative of low genetic barriers to crossing. It might be just as plausible to divide T. mononathum into two species instead of four subspecies (J. M. Gillett 1980), with T. monanthum encompassing populations with white rhizomes, and T. multicaule encompassing populations with taproots. Trifolium monanthum often forms dense mats. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 11. | FNA vol. 11. | ||||||||||||
Parent taxa | ||||||||||||||
Sibling taxa | ||||||||||||||
Subordinate taxa | ||||||||||||||
Name authority | Greene: Fl. Francisc., 27. (1891) | A. Gray: Proc. Amer. Acad. Arts 6: 523. (1865) | ||||||||||||
Web links |