Herbs annual, 6–35 cm, villous or glabrous. Stems erect or ascending, branched. Leaves palmate; stipules obliquely ovate, 0.4–1.2 cm, margins entire, toothed, or lacerate, apex acuminate; petiole 1–8 cm; petiolules 0.5 mm; leaflets 3, blades obovate or obcordate, 0.4–1.4 × 0.3–1.2 cm, base cuneate, veins fine, thickened distally, margins serrate, apex rounded or emarginate, surfaces villous or glabrous. Peduncles 1.5–7.4 cm. Inflorescences axillary or terminal, 10–17-flowered, subglobose, 0.8–1.7 × 0.5–1.5 cm; involucres cup-shaped, 0.5–1.5 cm, glabrous or sparsely hairy, lobes 8–12, ovate, conspicuously sharply toothed. Pedicels absent; bracteoles absent. Flowers 6–7 mm; calyx tubular-campanulate, 3–4 mm, glabrous, veins 10, tube 2.5–3.5 mm, lobes ± equal, triangular, not or minutely aristate, conspicuously toothed, margins membranous, orifice open; corolla pale pink or white, 6–9 mm, banner oblong, 6–9 × 2–3 mm, apex narrowly rounded or emarginate-mucronate. Legumes ovoid, 2–3 mm. Seeds 1 or 2, greenish, sometimes mottled, oblong, 1.5–2 mm, smooth. 2n = 16.

Phenology: Flowering Apr–Jul.
Habitat: Meadows, roadsides, dry slopes, fields, open oak or pine forests.
Elevation: 0–1500 m.

Distribution

• Generated Map
• Legacy Map

B.C., Calif., Idaho, Oreg., Wash., Mexico (Baja California), South America (Chile).

Discussion

Trifolium microdon is one of several clovers that have an apparently natural disjunct distribution between the western coast of South America (Chile) and western North America. Others include T. depauperatum var. depauperatum and T. macraei.

In herbarium specimens of Trifolium microdon, the folded involucre hides, or nearly hides, the calyces, whereas in herbarium specimens of similar T. microcephalum, the calyces are still visible.

Selected References

None.

Lower Taxa

None.