Trifolium andinum

Herbs perennial, 5–15 cm, pubescent. Stems erect or ascending, cespitose, much-branched. Leaves palmate; stipules oblanceolate, 0.5–1.4 cm, margins entire, apex acute-acuminate; petiole 0.5–4 cm; petiolules to 0.1 mm; leaflets 3, blades oblanceolate, often folded, 0.4–1.5 × 0.2–0.4 cm, base cuneate, veins obscure, margins subentire to denticulate distally, apex acute, mucronulate, surfaces villous. Peduncles between distal leaves or involucrelike structure and inflorescences 0.5–6 cm. Inflorescences terminal, usually formed of 2 sessile heads, 15–25-flowered, globose, 0.8–2 × 0.6–1.5 cm; involucres absent, distal stipules and leaves sometimes forming involucrelike structure. Pedicels straight, (0–)1–2 mm; bracteoles broadly ovate, truncate, membranous, to 0.5 mm. Flowers 10–15 mm; calyx tubular-campanulate, 6–9 mm, rough-hairy or glabrous, veins 10, tube 3–6 mm, lobes subequal, subulate, orifice open; corolla light purple, 10–15 mm, banner oblong, 9–13 × 3–4 mm, apex rounded or truncate; ovaries pubescent distally. Legumes ellipsoid, 4–5 mm. Seeds 1 or 2, brown, ovoid, 1.5–2 mm, smooth.

Phenology: Flowering May–Jun.
Habitat: Shale or clay bluffs and hilltops, crevices of volcanic or limestone rock, pinyon-juniper belt.
Elevation: 1600–2300 m.

Ariz., Colo., Nev., N.Mex., Utah, Wyo.

Discussion

Trifolium andinum ranges from central and southern Nevada into west-central Utah, north-central Arizona to southeastern Utah, north-central New Mexico, and northeastern Utah into southwestern Wyoming. Differentiation of T. andinum into subspecific taxa proved impossible, since no consistent gaps in morphological traits could be found.

Selected References

None.

Lower Taxa