Trifolium macrocephalum |
Trifolium howellii |
|
---|---|---|
big-head clover, large-head clover |
canyon clover, Howell's clover |
|
Habit | Herbs perennial, 5–25 cm, villous. | Herbs perennial, 30–100 cm, glabrous. |
Stems | erect or ascending, branched. |
erect, fistulose, unbranched or branched distally. |
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 ovate, 1.5–4.5 cm, margins usually entire, sometimes lobed, apex acuminate; petiole 0.5–20 cm; petiolules 1–1.5 mm; leaflets 3, blades ovate, elliptic, or rhombic, 3.5–9.5 × 2.3–5 cm, base cuneate, veins obscure, margins ± serrate, apex acute, rounded, or obtuse, surfaces glabrous. |
Inflorescences | terminal, 20–32-flowered, globose or ovoid-ellipsoid, 2.5–8 × 3–7 cm; involucres absent. |
terminal or axillary, 20–70-flowered, globose or ellipsoid, 2.5–4 × 2–2.5 cm, rachis prolonged beyond flowers, undivided or forked, often bearing sterile flower buds distally; involucres absent. |
Peduncles | 2–8 cm. |
3–11 cm. |
Pedicels | erect, 1–1.5 mm; bracteoles broadly ovate, membranous, to 0.5 mm, truncate. |
strongly reflexed in fruit, 1 mm; bracteoles minute, blunt or acute, membranous. |
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. |
10–14 mm; calyx campanulate, gibbous, 4–5.5 mm, glabrous, veins 10, tube 2–2.5 mm, lobes subequal, linear-lanceolate, orifice open; corolla white, lemon yellow, or greenish yellow, 11–12 mm, banner elliptic-oblong, 11–12 × 4–5 mm, apex obtuse. |
Legumes | ovoid, 4–5 mm. |
oblong or clavate, 4–5 mm. |
Seeds | 1 or 2, yellow or reddish, mitten-shaped to ellipsoid, 2.5–3 mm, smooth. |
1–3, reddish black or brown, angular, mitten-shaped, 2.5 mm, smooth or slightly roughened, dull. |
2n | = 32, 48. |
|
Trifolium macrocephalum |
Trifolium howellii |
|
Phenology | Flowering Apr–Jun. | Flowering Jun–Jul. |
Habitat | Rocky places, hard, compacted clay-gumbo, lava beds, sage-covered slopes, full sun. | Wet stream banks, wet meadows, flood plains, shady woodlands, springs, thickets. |
Elevation | 80–2500 m. [260–8200 ft.] | 800–2000 m. [2600–6600 ft.] |
Distribution |
CA; ID; NV; OR; WA
|
CA; OR
|
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 howellii is known from Del Norte, Humboldt, Siskiyou, and Trinity counties in California, and Clackamas, Douglas, Jackson, Josephine, Klamath, Lane, and Linn counties in Oregon (J. M. Gillett 1972). It has some of the largest leaves of any species of Trifolium in North America. (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) | S. Watson: Proc. Amer. Acad. Arts 23: 262. (1888) |
Web links |