Trifolium barbigerum
Pacif. Railr. Rep. 4(5): 79. 1857.
Herbs annual, 7–20 cm, puberulent or glabrous. Stems decumbent or erect, branched. Leaves palmate; stipules ovate-lanceolate, 0.5–1.1 cm, margins toothed or lacerate, apex acute-acuminate; petiole 1–10 cm; petiolules to 0.5 mm; leaflets 3, blades oblanceolate or obovate, 1.5–2.5 × 0.4–0.7 cm, base cuneate, veins fine, thickened distally, margins ± serrate or entire, apex rounded or retuse, surfaces pubescent or glabrous. Peduncles 5–10 cm. Inflorescences axillary or terminal, 5–20-flowered, subglobose or globose, 0.6–1.5 × 1–1.5 cm; involucres bowl-shaped, 5–15 mm, lobes 6–10, sharply setaceous-toothed, sinuses shallow. Pedicels straight, 0.2 mm; bracteoles absent. Flowers 4–6 mm; calyx campanulate, 5–9 mm, usually pubescent, rarely glabrous, veins 5, tube 2–3 mm, lobes ± equal, setaceous, often exceeding banner, orifice open; corolla usually lavender to purple, usually with white tips, rarely wholly white, 5–8 mm, banner broadly oblong, proximally inflated in fruit, distally narrowed into twisted tip, 6–8 × 6–8 mm, apex broadly acute. Legumes ovoid-ellipsoid, 2–3 mm. Seeds 1 or 2, brown, ellipsoid to subglobose, 1–1.5 mm, slightly roughened. 2n = 16.
Phenology: Flowering Apr–Jun.
Habitat: Vernal pools, stream banks, meadows, lawns.
Elevation: 0–1300 m.
Discussion
Trifolium barbigerum is relatively common and widespread in California, and extends northward into Coos, Curry, and Jackson counties in Oregon. It is morphologically similar to T. physanthum of Chile, to which it is a sister species in phylogenetic studies (N. W. Ellison et al. 2006).
Selected References
None.