Trifolium amoenum |
Trifolium cernuum |
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showy Indian clover, two-fork clover |
drooping clover, nodding clover |
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Habit | Herbs annual, 45–65 cm, canescent. | Herbs annual, 5–40 cm, glabrous. |
Stems | erect, branched from base and distally, or unbranched. |
prostrate, ascending, 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 triangular-lanceolate, 0.9–1 cm, margins entire, apex long-acuminate, reflexing; petiole 1–10 cm; petiolules to 1 mm; leaflets 3, blades obovate or obcordate, 0.4–1.5 × 0.4–1 cm, base cuneate, veins prominent, recurved, margins coarsely dentate, apex rounded, truncate, or emarginate, 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, 8–20-flowered, depressed-globose, 0.9–1.1 × 0.8–1 cm; involucres absent. |
Peduncles | 5–15 cm. |
0.6–1.5 cm, becoming shorter distally. |
Pedicels | absent; bracteoles cuplike, to 0.5 mm. |
reflexed in fruit, 0.5–2 mm; bracteoles lanceolate, 1 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. |
4–5.5 mm; calyx tubular-campanulate, 4 mm, glabrous, veins 10, tube 2–2.2 mm, lobes subequal, triangular-subulate, margins green, pink, or purple, orifice open; corolla pink, 4–5 mm, banner obovate, 4–5 × 1–2 mm, apex deeply emarginate. |
Legumes | obovoid, 4 mm. |
ovoid-ellipsoid, 4 mm. |
Seeds | 1, dark brown, ellipsoid, 2–3 mm, smooth. |
1–4, yellow, ovoid, 0.8–1 mm, minutely papillate. |
2n | = 16. |
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Trifolium amoenum |
Trifolium cernuum |
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Phenology | Flowering Apr–May. | Flowering May–Jul. |
Habitat | Grassy slopes, swales, clay soils. | Roadsides, lawns. |
Elevation | 0–100 m. (0–300 ft.) | 0–150 m. (0–500 ft.) |
Distribution |
CA
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CA; OR; SC; Asia; n Africa [Introduced in North America; introduced also in s Africa, Pacific Islands (New Zealand), Australia]
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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.) |
Trifolium cernuum is a relatively recent introduction in the flora area. Other than a record from wool mill waste in North Carolina in 1932, the earliest records are from the 1990s in California. (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) | Brotero: Phytogr. Lusit. Select. 1: 150, plate 62. (1816) |
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