Trifolium eriocephalum |
Trifolium oliganthum |
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woolly-head clover |
few-flower clover, few-flowerered clover |
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Habit | Herbs perennial, 12–46 cm, sparsely hairy to densely villous, appressed-pubescent, or glabrate. | Herbs annual, 10–50 cm, glabrous. | ||||||||||||||||||||
Stems | erect or decumbent, branched. |
erect, dichotomously branched. |
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Leaves | palmate; stipules lanceolate or ovate, 1–5 cm, margins entire or denticulate, apex acuminate or acute; petiole 1–15 cm; petiolules 1 mm; leaflets 3, blades linear, linear-elliptic, elliptic, lanceolate, lanceolate-oblong, or obovate, 1–5 × 0.4–1.2 cm, base cuneate, veins fine or ± thickened, margins denticulate or serrulate, apex acuminate or acute, surfaces appressed-pubescent abaxially, glabrous, densely villous, or sparsely or densely pilose adaxially. |
palmate; stipules lanceolate, 0.4–1.2 cm, margins lacerate, apex subulate; petiole 0.5–4 cm; petiolules to 0.5 mm; leaflets 3, blades linear, oblong, oblanceolate, or elliptic, 0.5–2.5 × 0.1–0.5 cm, base cuneate, veins fine or moderately thickened, margins entire, spinulose, or dentate, apex rounded or truncate, mucronate, surfaces glabrous. |
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Inflorescences | terminal or axillary, 25–70-flowered, inverted or horizontal, ellipsoid or globose to subglobose, 2–3 × 1–3 cm, rachis prolonged beyond flowers; involucres absent. |
axillary or terminal, 3–15-flowered, obconic, 0.3–1.2 × 0.3–0.8 cm; involucres flattened to bowl-shaped, 1–2 mm, when folded, not hiding flowers except proximally, incised 4/5–9/10 their length, lobes lanceolate-subulate. |
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Peduncles | bent distally, proximal to flowers, 3–18 cm. |
2.5–7.5 cm. |
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Pedicels | reflexed, to 0.3 mm; bracteoles absent. |
erect, 0.5–2 mm; bracteoles absent. |
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Flowers | 9–18 mm; calyx campanulate, curved in fruit, 4–11 mm, villous, veins 10, tube 1.5–2.5 mm, lobes unequal, 2–3 times tube, subulate, often strongly curved and twisted, plumose, orifice open; corolla white, cream, or purple, 8–16 mm, banner oblanceolate, 8–16 × 3–5 mm, apex rounded or retuse, recurved; ovaries pubescent distally. |
11–16 mm; calyx campanulate, slit between adaxial lobes, 4–5 mm, glabrous, veins 10, tube 2.5–5.2 mm, lobes triangular-subulate, 3-fid or shouldered below apex, orifice open; corolla lavender with white tips, keel petals purple, 6–8 mm, banner narrowly ovate-oblong, 6–8 × 2 mm, apex narrowly rounded, erose. |
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Legumes | ovoid, 2–3.5 mm. |
sessile, oblong, 2.1–3.2 mm. |
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Seeds | (1 or)2–4, yellow-brown to brown, mitten-shaped or subglobose, 1.2–2 mm, smooth. |
1 or 2 (or 3), reddish brown, mottled, lenticular or reniform, 1.2–1.3 mm, smooth. |
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2n | = 16. |
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Trifolium eriocephalum |
Trifolium oliganthum |
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Phenology | Flowering Mar–Jul. | |||||||||||||||||||||
Habitat | Stream banks, grassy, rocky slopes, meadows, fields. | |||||||||||||||||||||
Elevation | 0–1100 m. [0–3600 ft.] | |||||||||||||||||||||
Distribution |
w United States
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CA; OR; WA; BC
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Discussion | Subspecies 6 (6 in the flora). Trifolium eriocephalum was revised by J. M. Gillett (1971). The subspecies exhibit unusually complex distributional patterns, and overlapping morphological features sometimes make identifications problematic (M. Zohary and D. Heller 1984). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Trifolium oliganthum is relatively common throughout much of its range in California; it is found in a few scattered sites northward into Oregon, Washington, and British Columbia. Even though it closely resembles T. variegatum, it is placed near T. bifidum in molecular studies (N. W. Ellison et al. 2006). Trifolium hexanthum Greene ex A. Heller, which pertains here, is not a validly published name. (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 | ||||||||||||||||||||||
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Synonyms | T. pauciflorum, T. filipes, T. oliganthum var. sonomense, T. triflorum | |||||||||||||||||||||
Name authority | Nuttall in J. Torrey and A. Gray: Fl. N. Amer. 1: 313. (1838) | Steudel: Nomencl. Bot. ed. 2, 2: 707. (1841) | ||||||||||||||||||||
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