Family - Fabaceae

Stems - Trailing to sprawling, herbaceous, carinate, greenish red, from taproots, dense with retrorse uncinate prickles to +2mm long.

Leaves - Alternate, petiolate, bipinnate, stipulate, to 12cm long. Stipules filiform, to +6mm long. Petiole and rachis with antrorse uncinate prickles. Leaflets opposite, glabrous, ciliate margined, oblique at base, 5-6mm long, 2mm broad, oblong, mucronate, +/-16 pairs per pinna, opposite pairs folding together when touched.

Inflorescence - Axillary globose pedunculate clusters of +/-70 flowers. Flowers sessile or on pedicel to -1mm long. Peduncles to 7cm long, with antrorse uncinate prickles.

Flowers - Corolla tubular, 5-lobed, glabrous. Tube to 3mm long. Lobes 1mm long. Stamens 5-10, well exserted. Filaments pink, to 1.5cm long, glabrous. Anthers yellow, .2mm long. Style 2cm long, pink, glabrous. Ovary cylindric, green, 1.6mm long, striate, tuberculate. Calyx green, minute, .2mm long, glabrous, toothed. Fruit to +10cm long, linear, with prickles, carinate.

Fruits.

Flowering - May - September.

Habitat - Glades, open woods, thickets, prairies, roadsides.

Origin - Native to U.S.

Other info. - Although very attractive and neat to play with, I wouldn't recommend getting too friendly with this plant. The uncinate (hence the name) prickles grab on to most anything and are hesitant to ever let go. Despite the prickles, the plant is eaten by many animals and is very nutritious.
A common synonym is S. nuttallii (DC) Standley

Photographs taken off Highway 13, St. Clair County, MO., 7-7-00, and in Big Spring Park, Carter County, MO., 6-7-03.