Trifolium macrocephalum |
Trifolium vesiculosum |
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big-head clover, large-head clover |
arrow-leaf clover |
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Habit | Herbs perennial, 5–25 cm, villous. | Herbs annual, 15–70 cm, glabrous. |
Stems | erect or ascending, branched. |
erect or 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 linear-lanceolate, 1–3.5 cm, margins entire, apex subulate or setaceous; petiole 0.5–10 cm; petiolules 1 mm; leaflet 3, blades obovate to oblong, elliptic or lanceolate, 0.5–4 × 0.5–1.5 cm, base cuneate, veins prominent, thickened, margins spinulose-denticulate, apex apiculate, surfaces glabrous. |
Inflorescences | terminal, 20–32-flowered, globose or ovoid-ellipsoid, 2.5–8 × 3–7 cm; involucres absent. |
terminal or axillary, 50–100+-flowered, globose, ovoid, or oblong, 3–6 × 2–3.5 cm; involucres absent. |
Peduncles | 2–8 cm. |
1–12 cm. |
Pedicels | erect, 1–1.5 mm; bracteoles broadly ovate, membranous, to 0.5 mm, truncate. |
absent; bracteoles lanceolate, 6–7 mm, acuminate. |
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. |
12–16 mm; calyx urceolate, not bilabiate, inflated in fruit, 6–10 mm, glabrous, veins 20–36, connected by transverse veins in fruit, tube 3–5 mm, lobes reflexed, subequal, subulate, as long as tube, orifice constricted; corolla white becoming pink, 12–15 mm, banner ovate, broadly clawed, striate, 12–15 × 2–4 mm, apex acute-acuminate. |
Legumes | ovoid, 4–5 mm. |
ellipsoid, 2.5–2.5 mm, shorter than calyx. |
Seeds | 1 or 2, yellow or reddish, mitten-shaped to ellipsoid, 2.5–3 mm, smooth. |
2 or 3, brown, ovoid, 1–1.5 mm, roughened. |
2n | = 32, 48. |
= 16. |
Trifolium macrocephalum |
Trifolium vesiculosum |
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Phenology | Flowering Apr–Jun. | Flowering Apr–Jul. |
Habitat | Rocky places, hard, compacted clay-gumbo, lava beds, sage-covered slopes, full sun. | Fields, roadsides, forest openings. |
Elevation | 80–2500 m. [260–8200 ft.] | 0–1000 m. [0–3300 ft.] |
Distribution |
CA; ID; NV; OR; WA
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AL; AR; CA; FL; GA; LA; MA; MO; MS; OK; OR; SC; TX; VA; WA; s Europe; e Europe; w Asia [Introduced in North America]
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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 vesiculosum was first introduced into cultivation in the United States in 1963 and is grown in southern and western states (J. D. Miller and H. D. Wells 1985). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 11. | FNA vol. 11. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Lupinaster macrocephalum | |
Name authority | (Pursh) Poiret in J. Lamarck et al.: Encycl., suppl. 5: 336. (1817) | Savi: Fl. Pis. 2: 165. (1798) — (as vessiculosum) |
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