Deep-rooted perennial with slender stems to 1 m; stipules lance-ovate, toothed; lfls oblanceolate or oblong to narrowly obovate, 1.5-3 cm, toothed at the summit; peduncles erect, about equaling the subtending lvs; heads subglobose to short-cylindric; fls 6-12 mm, on pedicels 2-3 mm; cal-lobes lance-linear, 1-3 mm, about equaling the tube; pod finely hairy; 2n=16, 32. June-Sept. A highly diversified species, with pronounced but confluent variation. The two subspecies characterized below are connected by a hybrid swarm called ssp. ضaria (Martyn) Arcang. Additional variants may be characterized in more detailed treatments.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
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Kearney and Peebles 1969, McDougal 1973
Duration: Perennial Nativity: Non-Native Lifeform: Forb/Herb General: Herbaceous annuals to perennials, to 90 cm tall, stems decumbent to erect and ascending, much branched, herbage glabrous to puberulent. Leaves: Alternate, pinnately trifoliate, leaflets lanceolate to obovate, 10-25 mm long, sharply serrate at the tip, margins dentate, petioles 5-20 mm long, stipules 5-8 mm long, lanceolate, entire, or toothed. Flowers: Small, greenish-yellow or violet to deep purple, corolla 6-12 mm long, calyx 5-6 mm long, stamens with 1 separate from the other 9 (diadelphous), flowers borne in dense, subcapitate racemes. Fruits: Pods spirally coiled, glabrous, indehiscent. Seeds several. Ecology: Found in waste areas, roadsides, escaped from cultivated areas, below 5,000 ft (1524 m); flowering April-October. Distribution: Introduced from Eurasia, widely cultivated across the western United States. Notes: Alfalfa smells amazing when fresh. The purple flowers are a good indicator for this species; most other species in Arizona have yellow flowers. Look for it especially near cultivated fields and roadsides near livestock. Ethnobotany: A poultice of the heated leaves applied to the ear for earaches. The plant was cultivated, harvested, dried, stacked or stored in hogans and fed to livestock in winter, the plants were placed above and below black tree lichen and camas in cooking pits for the sweet flavor, and the plant was used for horse feed. Synonyms: None Editor: LCrumbacher 2011 Etymology: Medicago is derived from Medike, or medick, the Greek name for alfalfa, which came to Greece from Medea, while sativa means "that which is sown," indicating the plant is a cultivated one.