Trifolium macrocephalum |
Trifolium microcephalum |
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big-head clover, large-head clover |
small-head clover |
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Habit | Herbs perennial, 5–25 cm, villous. | Herbs annual, 3–55 cm, densely to sparsely pubescent. |
Stems | erect or ascending, branched. |
erect to ascending, 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 obliquely ovate, 0.4–1.2 cm, margins entire or slightly serrate, apex acuminate; petiole 1–5 cm; petiolules 0.5 mm; leaflets 3, blades oblanceolate, obovate, or obcordate, 0.4–1.7 × 0.3–1.1 cm, base cuneate, veins fine or slightly thickened, margins setose, often dentate distally, apex usually retuse, rarely rounded, surfaces villous. |
Inflorescences | terminal, 20–32-flowered, globose or ovoid-ellipsoid, 2.5–8 × 3–7 cm; involucres absent. |
axillary or terminal, 10–40-flowered, globose, 0.5–1.3 × 0.4–1.2 cm; involucres flattened or bowl-shaped, 0.4–1 cm, when folded, nearly completely hiding calyces, villous, incised 1/2 their length, lobes 5–12, lanceolate-ovate, entire or slightly toothed proximally, acuminate. |
Peduncles | 2–8 cm. |
1–8 cm. |
Pedicels | erect, 1–1.5 mm; bracteoles broadly ovate, membranous, to 0.5 mm, truncate. |
absent; 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. |
4–6 mm; calyx campanulate-tubular, 3–5.5 mm, pubescent, veins 10, tube 1.8–2.5 mm, lobes ± equal, triangular-aristate, margins hyaline, wavy, orifice open; corolla white or pink to lavender, 4–6 mm, banner oblong, 3–6 × 1–2 mm, apex emarginate. |
Legumes | ovoid, 4–5 mm. |
broadly ellipsoid, 1.5–2 mm. |
Seeds | 1 or 2, yellow or reddish, mitten-shaped to ellipsoid, 2.5–3 mm, smooth. |
1, yellow, reddish mottled, oblong, 1.5 mm, smooth. |
2n | = 32, 48. |
= 16. |
Trifolium macrocephalum |
Trifolium microcephalum |
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Phenology | Flowering Apr–Jun. | Flowering Mar–Jul. |
Habitat | Rocky places, hard, compacted clay-gumbo, lava beds, sage-covered slopes, full sun. | Meadows, roadsides, stream banks, forest clearings, grassy slopes. |
Elevation | 80–2500 m. [260–8200 ft.] | 0–2500 m. [0–8200 ft.] |
Distribution |
CA; ID; NV; OR; WA
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AK; AZ; CA; ID; MT; NV; OR; WA; BC; Mexico (Baja California)
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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 microcephalum is common in much of its range in California and northward into Oregon, and is rare in much of the rest of its range. It is closely allied with the Chilean T. vernum Philippi (N. W. Ellison et al. 2006), which it resembles greatly, and from which it is distinguished by its shorter calyx lobes (M. Zohary and D. Heller 1984). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 11. | FNA vol. 11. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Lupinaster macrocephalum | Lojaconoa microcephala, T. microcephalum var. bipedale, T. microcephalum var. lemmonii |
Name authority | (Pursh) Poiret in J. Lamarck et al.: Encycl., suppl. 5: 336. (1817) | Pursh: Fl. Amer. Sept. 2: 478. (1813) |
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