Trifolium macrocephalum |
Trifolium oliganthum |
|
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big-head clover, large-head clover |
few-flower clover, few-flowerered clover |
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Habit | Herbs perennial, 5–25 cm, villous. | Herbs annual, 10–50 cm, glabrous. |
Stems | erect or ascending, branched. |
erect, dichotomously branched. |
Leaves | palmate; stipules ovate, obovate, or oblong, 1–3 cm, margins entire, irregularly lobed, or serrate, apex acute or acuminate; petiole 1–14 cm; petiolules 0.9–1.2 mm; leaflets (5–)7–9, blades broadly to narrowly obovate, often folded, 1–2.7 × 0.4–1.1 cm, base cuneate, veins thickened, especially distally, margins serrulate, apex rounded or truncate, apiculate, surfaces villous abaxially, sparsely villous to glabrate 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. |
Inflorescences | terminal, 20–32-flowered, globose or ovoid-ellipsoid, 2.5–8 × 3–7 cm; 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. |
Peduncles | 2–8 cm. |
2.5–7.5 cm. |
Pedicels | erect, 1–1.5 mm; bracteoles broadly ovate, membranous, to 0.5 mm, truncate. |
erect, 0.5–2 mm; bracteoles absent. |
Flowers | 20–30 mm; calyx campanulate, 10–22 mm, villous, veins 10–15, tube 2.5–4 mm, lobes subequal, subulate, plumose, orifice open; corolla white, creamy white, or pinkish, keel petals deep pink, 20–28 mm, banner ovate or oblong, 20–28 × 10–13 mm, apex rounded or slightly emarginate. |
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. |
Legumes | ovoid, 4–5 mm. |
sessile, oblong, 2.1–3.2 mm. |
Seeds | 1 or 2, yellow or reddish, mitten-shaped to ellipsoid, 2.5–3 mm, smooth. |
1 or 2 (or 3), reddish brown, mottled, lenticular or reniform, 1.2–1.3 mm, smooth. |
2n | = 32, 48. |
= 16. |
Trifolium macrocephalum |
Trifolium oliganthum |
|
Phenology | Flowering Apr–Jun. | Flowering Mar–Jul. |
Habitat | Rocky places, hard, compacted clay-gumbo, lava beds, sage-covered slopes, full sun. | Stream banks, grassy, rocky slopes, meadows, fields. |
Elevation | 80–2500 m. [260–8200 ft.] | 0–1100 m. [0–3600 ft.] |
Distribution |
CA; ID; NV; OR; WA
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CA; OR; WA; BC
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Discussion | Trifolium macrocephalum has the largest inflorescences of any clover. Trifolium megacephalum Nuttall (1818) is an illegitimate replacement name for Lupinaster macrocephalum Pursh. (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.) |
Source | FNA vol. 11. | FNA vol. 11. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Lupinaster macrocephalum | T. pauciflorum, T. filipes, T. oliganthum var. sonomense, T. triflorum |
Name authority | (Pursh) Poiret in J. Lamarck et al.: Encycl., suppl. 5: 336. (1817) | Steudel: Nomencl. Bot. ed. 2, 2: 707. (1841) |
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