Trifolium macrocephalum |
Trifolium buckwestiorum |
|
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big-head clover, large-head clover |
Santa Cruz clover |
|
Habit | Herbs perennial, 5–25 cm, villous. | Herbs annual, 5–40 cm, glabrous. |
Stems | erect or ascending, branched. |
decumbent to ascending or erect, slightly 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 whitish with prominent green veins, ovate, 0.3–0.5 cm, margins lacerate, apex acute to acuminate; petiole 1–2.4 cm; petiolules to 0.5 mm; leaflets 3, blades obovate to elliptic, 0.6–1.5 × 0.3–0.8 cm, base cuneate, veins ± thickened distally, margins denticulate, sometimes entire proximally, apex rounded, acute, or retuse, surfaces glabrous. |
Inflorescences | terminal, 20–32-flowered, globose or ovoid-ellipsoid, 2.5–8 × 3–7 cm; involucres absent. |
terminal or axillary, 15–20-flowered (early inflorescences hidden in stipules, subsessile, 2–5-flowered, flowers cleistogamous), subglobose, 0.5–0.8 × 0.6–0.8 cm; involucres flattened or shallowly bowl-shaped, 6–8 mm, when folded, nearly hiding calyces, glabrous or sparsely hairy, lobes 4 or 5, ± parallel-sided, 3 or 4-toothed. |
Peduncles | 2–8 cm. |
1–3.5 cm. |
Pedicels | erect, 1–1.5 mm; bracteoles broadly ovate, membranous, to 0.5 mm, truncate. |
straight, to 0.5 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. |
7–8 mm; calyx tubular, 4–5 mm, glabrous, veins 10, tube 2–2.5 mm, lobes subequal, triangular, margins conspicuously 2 or 3-toothed, apex aristate, orifice open; corolla pale pink or white, 6–7 mm, banner oblong, 5–7 × 1 mm, apex emarginate or erose. |
Legumes | ovoid, 4–5 mm. |
ovoid, 2.5 mm. |
Seeds | 1 or 2, yellow or reddish, mitten-shaped to ellipsoid, 2.5–3 mm, smooth. |
1, dark brown, slightly mottled, ovoid, 2 mm, smooth. |
2n | = 32, 48. |
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Trifolium macrocephalum |
Trifolium buckwestiorum |
|
Phenology | Flowering Apr–Jun. | Flowering May–Jun. |
Habitat | Rocky places, hard, compacted clay-gumbo, lava beds, sage-covered slopes, full sun. | Meadows, roadsides, grassy hillsides. |
Elevation | 80–2500 m. [260–8200 ft.] | 0–300 m. [0–1000 ft.] |
Distribution |
CA; ID; NV; OR; WA
|
CA |
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 buckwestiorum, which ranges from Mendocino to Monterey counties, is unique among clovers in North America because of its aboveground cleistogamous, axillary flowers. The only other clover in North America that produces cleistogamous flowers is T. amphianthum, which produces its cleistogamous flowers at ground level and then pushes them into the substrate. (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) | Isely: Madroño 39: 90, fig. 2. (1992) |
Web links |