Astragalus mexicanus A. DC. - Hog Plum

Astragalus mexicanus plant

Family - Fabaceae

Stems - Multiple from base, from a taproot and branched caudex, ascending to erect, branching, herbaceous, glabrescent below, with antrorse appressed hairs above,(more dense in young plants), often reddish, to 50cm tall.

Astragalus mexicanus stemStem and leaf stipule.

Leaves - Alternate, odd-pinnate, stipulate. Stipules to 1cm long, 5mm broad at base, with scarious margins, acute to acuminate, glabrous but with papillate margins. Leaflets opposite to subopposite, +/-10 pairs per leaf, to 1.5cm long, 7-8mm broad, rounded at apex, oblong to oblong-ovate, entire but with cilia on margins, glabrous above, sericeous below, with short petiolules. Petiolules to 1mm long, pilose.

Astragalus mexicanus leaf

Inflorescence - Axillary long-pedunculate racemes. Peduncles to +/-7cm long, sericeous. Pedicels to 2mm long, densely sericeous to appressed pubescent. Raceme to +/-5cm long(tall). Each flower subtended by a minute lanceolate bract. Bracts to 3mm long, 1mm broad at base, with green midvein.

Astragalus mexicanus inflorescence

Flowers - Corolla papilionaceous, creamy white. Standard to 1.9cm long, 8mm broad at apex, glabrous. Keels apically connate and purplish at apex, folded around style and stamens. Stamens diadelphous. Filaments glabrous, white, to 1.3cm long. Anthers orange-red, .7mm long. Ovary green, 3-4mm long, terete, glabrous. Style greenish white, 1.1cm long, apically curved upward, glabrous. Calyx creamy white to yellowish-green, 1cm long, 3-4mm in diameter, tomentose externally, glabrous internally, 5-toothed. Teeth to -2mm long, acute, unequal. Top 2 teeth more triangular then the lower 3. Fruits plump, +/-2cm in diameter, subglobose, reddish-purple when ripe, glabrous.

Astragalus mexicanus flowerFlowers close-up.

Astragalus mexicanus fruitsFruits.

Flowering - March - May.

Habitat - Rocky open woods, glades, bluffs, rocky prairies.

Origin - Native to U.S.

Other info. - This is an attractive species which can be found in the lower 2/3 of the state. The plant prefers dry open areas. It should be cultivated more frequently. This species is easy to ID while in flower because of its tomentose calices, whitish flowers, and plumlike fruits. The fruits of this species can be eaten raw or cooked while green and unripe.
Our plants belong to variety trichocalyx (Nutt.) Fern.
A synonym for this species is A. crassicarpus var. trichocalyx (Nutt.) Barneby.

Photographs taken at the Piney Creek Wilderness, Mark Twain National Forest, Barry County, MO., 4-4-04, and at Whetstone Conservation Area, Callaway County, MO., 4-17-04.


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