Duration: Annual

Nativity: Native

Lifeform: Vine

General: Slender annual with twining, sparsely puberulent to glabrate stems 20-120 cm long, bearing subulate stipules, 0.4-1.5 mm wide, 2-5 mm long.

Leaves: Pinnately trifoliolate with thin triangular leaflets, linear-lanceolate to narrowly lanceolate, 3-12 mm wide at base, 3-7 cm long, lateral ones sometimes slightly subhastate on one side, attenuate at apex, petioles shorter than leaflets, 1-3 cm long.

Flowers: Slender peduncles 2-6 cm long, puberulent pedicels 1-5 mm long, calyx broadly campanulate, 2.5-3.5 mm long, sparsely puberulent to glabrate, deltoid or narrowly ovate teeth shorter than tube; corollas ranging from white to yellowish green to purple; banner 5-8 mm long; keel strongly twisted or coiled; pod slightly falcate, 3-5 mm wide, 4-6 cm long, strongly compressed, finely puberulent.

Fruits: Slightly falcate, 3-5 mm wide, 4-6 cm long, strongly compressed, sparsely to moderately but finely puberulent, attenuate at apex, distinctly reticulate-venose.

Ecology: Found on rocky slopes, often in and among low brush from 3,000-6,000 ft (914-1829 m); flowers August-October.

Notes: The triangular shape of the leaves is distinctive for this species. This description is for the more common variant var. tenuifolius while there is a more broadly ovate to ovate-rhombic var. latifolius.

Ethnobotany: Used for toothaches, cultivated and eaten, made into flour, generally an important food crop in the desert.

Etymology: Phaseolus is from Greek phaselos, a little boat or light vessel, referring to its pod, while acutifolius means sharp or acute leaved.

Synonyms: None

Editor: SBuckley, 2010