Trifolium amoenum |
Trifolium fucatum |
|
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showy Indian clover, two-fork clover |
bull clover, sour clover |
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Habit | Herbs annual, 45–65 cm, canescent. | Herbs annual, 10–80 cm, glabrous or glabrescent. |
Stems | erect, branched from base and distally, or unbranched. |
erect or ascending, unbranched or densely dichotomously 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 or lanceolate, 1–3 cm, margins entire or toothed, apex usually acuminate, sometimes 2-fid; petiole 3–15 cm; petiolules 1–1.5 mm; leaflets 3, blades broadly obovate, orbiculate, or rhombic-obovate, 0.8–4 × 0.7–3 cm, base broadly cuneate, veins obscure, thickened near leaflet margin, margins remotely dentate to densely serrulate-dentate, apex rounded or slightly retuse, surfaces glabrous or glabrate. |
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, 10–30-flowered, subglobose or globose, 1–4 × 1–4 cm; involucres broadly bowl-shaped, 4–15 mm, lobes 3–8, lanceolate, acuminate, undivided or 2- or 3-fid. |
Peduncles | 5–15 cm. |
3–13 cm. |
Pedicels | absent; bracteoles cuplike, to 0.5 mm. |
straight, 1 mm; bracteoles distinct or connate, broadly ovate, 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. |
10–27 mm; calyx campanulate, 3–8 mm, glabrous, veins 10, tube 1.5–2.5 mm, lobes 5–10, unequal, undivided or 3-fid, long-acuminate, orifice open; corolla creamy white to yellow, pink to purple in age, keel petals rarely dark purple, 10–27 mm, banner broadly ovate, inflated in fruit, not distally twisted, 10–27 × 6–15 mm, apex rounded, erose. |
Legumes | obovoid, 4 mm. |
stipitate, linear, 7–8 mm. |
Seeds | 1, dark brown, ellipsoid, 2–3 mm, smooth. |
3–8, gray, mottled, globose, 1.6–2 mm, reticulate. |
2n | = 16. |
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Trifolium amoenum |
Trifolium fucatum |
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Phenology | Flowering Apr–May. | Flowering Apr–Jun. |
Habitat | Grassy slopes, swales, clay soils. | Moist places, meadows, roadsides. |
Elevation | 0–100 m. (0–300 ft.) | 0–1000 m. (0–3300 ft.) |
Distribution |
CA
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CA; OR; WA [Introduced in Asia (China, Japan)]
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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 fucatum is known as an invasive species in Japan (T. Mito and T. Uesugi 2004) and has also been introduced in China (specimen at BM). A single old collection exists from British Columbia, but the species has not been collected in that province again. The Michigan record of the species is an inadvertent waif. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 11. | FNA vol. 11. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | T. flavulum, T. fucatum var. flavulum, T. fucatum var. gambelii, T. fucatum var. virescens, T. gambelii, T. physopetalum, T. virescens | |
Name authority | Greene: Fl. Francisc., 27. (1891) | Lindley: Edwards’s Bot. Reg. 22: plate 1883. (1836) |
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