Trifolium microcephalum |
Trifolium beckwithii |
|
---|---|---|
small-head clover |
Beckwith's clover |
|
Habit | Herbs annual, 3–55 cm, densely to sparsely pubescent. | Herbs perennial, 5–50 cm, glabrous. |
Stems | erect to ascending, branched. |
erect or ascending, unbranched or several stems clumped from crown. |
Leaves | 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. |
palmate; stipules narrowly ovate, lanceolate, or linear-lanceolate, 1–2 cm, margins entire or toothed, apex acute; petiole 0.5–20 cm; petiolules 1 mm; leaflets 3, blades usually rhombic, oblong, or elliptic, sometimes ovate, 2.5–5 × 0.6–2 cm, base cuneate, veins slightly thickened, margins setose-serrulate, apex obtuse or retuse, surfaces glaucous abaxially, glabrous. |
Inflorescences | 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. |
terminal or axillary, 30–70+-flowered, globose or ovoid becoming subglobose, 1.5–4 × 1.8–3.3 cm, rachis prolonged beyond flowers, undivided or forked, often bearing sterile flower buds distally; involucres absent. |
Peduncles | 1–8 cm. |
straight, thick, 5–25 cm. |
Pedicels | absent; bracteoles absent. |
strongly reflexed in fruit, 1–1.5 mm; bracteoles minute. |
Flowers | 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. |
11–14 mm, sweetly fragrant; calyx campanulate, gibbous, 4–6 mm, glabrous, veins 5, tube 2–3 mm, lobes unequal, narrowly triangular or subulate, orifice open; corolla light purplish, sometimes with pink tips, 10–13 mm, banner straight, obovate to broadly elliptic, 13–18 × 6–8 mm, apex rounded or retuse, apiculate. |
Legumes | broadly ellipsoid, 1.5–2 mm. |
oblong, 5 mm. |
Seeds | 1, yellow, reddish mottled, oblong, 1.5 mm, smooth. |
2–4, reddish brown, flattened globose, 1.5–2 mm, smooth. |
2n | = 16. |
= 48. |
Trifolium microcephalum |
Trifolium beckwithii |
|
Phenology | Flowering Mar–Jul. | Flowering May–Jul. |
Habitat | Meadows, roadsides, stream banks, forest clearings, grassy slopes. | Moist, grassy meadows along streams. |
Elevation | 0–2500 m. (0–8200 ft.) | 1200–2000 m. (3900–6600 ft.) |
Distribution |
AK; AZ; CA; ID; MT; NV; OR; WA; BC; Mexico (Baja California)
|
CA; ID; MT; NV; OR; SD; UT; WA
|
Discussion | 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.) |
Disjunct populations of Trifolium beckwithii found in South Dakota are over 1200 km east of the nearest populations in Montana. The South Dakota populations appear to have been long-distance introductions from populations in northern California, based on molecular data (M. R. Duvall et al. 1999). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 11. | FNA vol. 11. |
Parent taxa | Fabaceae > subfam. Faboideae > Trifolium | Fabaceae > subfam. Faboideae > Trifolium |
Sibling taxa | ||
Synonyms | Lojaconoa microcephala, T. microcephalum var. bipedale, T. microcephalum var. lemmonii | |
Name authority | Pursh: Fl. Amer. Sept. 2: 478. (1813) | Brewer ex S. Watson: Proc. Amer. Acad. Arts 11: 128. (1876) |
Web links |
|