Herbs perennial, 5–30 cm, glabrous or sparsely pilose; rhizomes absent, roots stout, branched. Stems pros­trate to ascending, branched. Leaves palmate; stipules lanceolate-ovate, 0.7–1.3 cm, margins entire, apex acuminate; petiole 1–8.5 cm; petiolules 1–1.5 mm; leaflets 3, blades oblanceolate or obovate, 0.5–2.9 × 0.4–1.3 cm, base cuneate, veins prominent, margins den­ticulate to spinulose, apex usually rounded or truncate, sometimes retuse, surfaces glabrous. Peduncles 4–6 cm. Inflorescences axillary or terminal, 10–20-flowered, obconic, globose, or subglobose, 1.7–2.5 × 1.–1.5 cm; involucres broadly campanulate, 6–8 mm, incised ± 3/4 their length, lobes 15–20, linear-lanceolate, entire, acuminate. Pedicels erect to slightly reflexed, 1–2 mm; bracteoles ovate, 0.5 mm. Flowers 10–16 mm; calyx campanulate, 6–10 mm, glabrous, veins 10, tube 2–2.3 mm, lobes ± equal, subulate, 3–5 mm, orifice open; corolla white to pale purple, keel petals with dark purple-red tips, 11–13 mm, banner oblong, 11–13 × 4–5 mm, apex retuse. Legumes short-stipitate, oblong, 3.5–5 mm. Seeds 1 or 2, olive-brown, mottled purple, oblong, 1.5 mm, smooth, semiglossy. 2n = 16.

Phenology: Flowering Jun–Oct.
Habitat: Disturbed areas in pine, fir, or spruce forests.
Elevation: 2300–2800 m.

Distribution

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Ariz., N.Mex., Mexico (Chihuahua).

Discussion

Trifolium pinetorum is found in Cochise, Coconino, Pima, and Santa Cruz counties in Arizona, and Catron, Grant, Lincoln, and Otero counties in New Mexico, as well as the Sierra Madre in Chihuahua, Mexico. It occupies disturbed areas in pine-fir-spruce forests, and has adapted well to anthropogenic disturbances, such as roadsides and other graded areas (J. M. Gillett 1980).

Selected References

None.

Lower Taxa

None.