Medicago sativa L. - Alfalfa

Medicago sativa plant

Family - Fabaceae

Stems - To 1m tall, 4-angled, erect or ascending, glabrous to pubescent, multiple from base, branching, herbaceous, from taproot.

Medicago sativa stem

Leaves - Alternate, trifoliolate, petiolate, stipulate. Stipules lanceolate, to +1cm long, toothed to entire. Leaflets typically oblanceolate, obovate or oblong, toothed to entire, to +2cm long, -1cm broad, typically mucronate, glabrous to sparse arachnoid pubescent below.

Inflorescence - Compact axillary pedunculate racemes, with up to 40 flowers. Peduncle to +/-3cm long, typically pubescent. Cluster globose to subglobose.

Medicago sativa inflorescence

Flowers - Corolla purple to whitish, papilionaceous, to 1cm long. Standard to 1cm long, 5mm broad. Stamens diadelphous. Calyx tube to 5mm long, 2mm in diameter, 5-lobed, typically glabrous. Lobes attenuate, to 4mm long, equal to subequal.

Medicago sativa flowerFlower close-up.

Fruits - Coiled pods to 8mm long.

Flowering - May - September.

Habitat - Waste ground, disturbed sites, roadsides, railroads. Also cultivated.

Origin - Native to Eurasia.

Other info. - M. sativa is the only species of Medicago in Missouri with purple flowers. As you can see from the above photos, the flowers are variable in color. The flowers of some cultivated plants can be greenish-yellow also. Some plants may also have fruits which are only slightly coiled to straight.
The plant is also quite variable in its pubescence.
Alfalfa is a very important crop because of its high protein content.

Photographs taken somewhere in North Carolina, 5-16-03.


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