Medicago minima
Cat. Piante Siena, 61. 1776.
Herbs: shoot pubescent, hairs eglandular and/or gland-tipped. Stems ascending or procumbent. Stipules: margins entire or minutely dentate at base. Leaflets: blades usually obovate, rarely oblanceolate, 5–8(–12) × 2–7 mm, margins serrate on distal 1/3. Inflorescences 2–5(–8)-flowered, racemes. Flowers 2–4.5(–6) mm; calyx pubescent, hairs eglandular and/or glandular, lobes equal to tube; corolla yellow, less than 2 times length of calyx. Legumes with 3–5 coils, discoid, cylindrical, or ovoid, 3–5 × 2.5–6 mm, hairs glandular and/or eglandular, margin usually prickly, sometimes tuberculate, prickles, when present, often relatively thin and flexible, base 2-rooted, 1 root arising in dorsal suture, other in submarginal vein; faces soft, coil face with strongly curved, unbranched radial veins entering broad, veinless margin that occupies 1/3 outer radius of coil face. Seeds 3–10, yellow to light brown, somewhat reniform, 1.5–2.5 × 0.9–1.3 mm; radicle 1/2 seed length. 2n = 16.
Phenology: Flowering spring–summer.
Habitat: Hillsides, fields, sand dunes, forest edges, rural sites.
Elevation: 0–1400 m.
Distribution
Introduced; Ala., Ariz., Calif., Conn., Fla., Idaho, Kans., La., Md., Mass., Mich., Miss., Mo., N.J., N.Mex., N.Y., N.C., Okla., Oreg., Pa., R.I., S.C., Tenn., Tex., Va., Wash., Eurasia, Africa, introduced also in South America (Argentina, Uruguay), Pacific Islands (Hawaii, New Zealand), Australia.
Discussion
Medicago minima has been only slightly developed to date for agricultural purposes, although in areas where it grows it is considered to be good forage. In Argentina and Australia, M. minima is an extremely important component of the rangelands used for livestock grazing. The first cultivar of M. minima to be registered (as ‘Devine’) was released in 2005 by the Texas Agricultural Experiment Station.
Medicago minima is most frequently confused with M. laciniata, but M. minima has much hairier foliage and much less dissected stipules.
Selected References
None.