Trifolium dichotomum

Herbs annual, 15–30 cm, canescent. Stems erect, branched from base and distally, or unbranched. Leaves palmate; stipules ovate or elliptic, 0.3–1 cm, margins entire, ciliate, apex acuminate; petiole 0.5–6.5 cm; petiolules 0.5–0.7 mm; leaflets 3, blades obovate or oblanceolate, 0.5–1.5 × 0.2–1.1 cm, base cuneate, veins obscure or slightly thickened, margins dentate, apex rounded or emarginate, surfaces pilose or glabrescent. Peduncles 2.5–10 cm. Inflorescences terminal or axillary, 15–35-flowered, ovoid-ellipsoid, 1.1–2.2 × 1–1.5 cm; involucres absent. Pedicels absent; bracteoles cuplike, to 0.5 mm. Flowers 10–12 mm; calyx tubular, 4–8 mm, densely pubescent, veins 20–30, tube 2–4 mm, lobes nearly equal, appearing rigidly erect, linear-setaceous, plumose, sinuses acute, orifice open; corolla red-violet to pink, with pink or white tips, 7–12 mm, banner ovate-oblong, 9–11 × 3–4 mm, apex broadly rounded, emarginate. Legumes obovoid, 3–3.5 mm. Seeds 1, yellow-brown, ellipsoid, 2–2.5 mm, smooth.

Phenology: Flowering Apr–May.
Habitat: Grassy slopes, meadows, adjacent to chaparral, serpentine soils, coastal dunes, open slopes, meadows, oak woodlands, disturbed areas.
Elevation: 0–1700 m.

B.C., Calif., Oreg., Wash.

Discussion

Trifolium dichotomum is reportedly tetraploid (H. Wexelsen 1928) and closely related to the diploid T. albopurpureum. A so-called small form of T. dichotomum was named T. dichotomum var. turbinatum [T. californicum forma turbinatum (Jepson) McDermott].

Selected References

None.

Lower Taxa