Psoralea tenuiflora Pursh - Scurfy Pea

Psoralea tenuiflora plant

Family - Fabaceae

Stems - Multiple from the base, to 80cm tall, branching in upper half, herbaceous, appressed pubescent below, densely appressed to slightly spreading pubescent above. Hairs mostly in distinct longitudinal lines with some sparse pubescence between the lines, from a branched taproot.

Leaves - 3-7 foliolate, petiolate, stipulate. Stipules to +/-7mm long, 1.5mm broad, linear, densely pubescent below and on margins. Lower petioles to -2.5cm long, densely appressed antrorse pubescent. Leaflets to 4cm long, 8mm broad, slightly pitted above, entire, very sparse pubescent to glabrous above, appressed pubescent below, short-mucronate.

Psoralea tenuiflora leaves

Inflorescence - Lateral and terminal racemes to +/-7cm tall(long), densely-flowered. Peduncles to 7cm long, densely antrorse appressed pubescent. Flowers 1-4 per node, subtended by a small bract. Bract to 2mm long. Pedicel to 1.7mm long, hirsute.

Flowers - Corolla deep purple, drying to a tan color, papilionaceous. Standard to 6mm long, 4-5mm broad. Stamens diadelphous. Style 2.2mm long, glabrous. Ovary .9mm long, glabrous. Calyx tube to 1.7mm long, purple, 5-lobed to weakly bilabiate, hirsute. 4 of the lobes subequal. Upper lobe larger, to 2mm long. All lobes ciliate-margined.

Psoralea tenuiflora flowers

Flowering - May - September.

Habitat - Rocky open glades, prairies, open woods.

Origin - Native to U.S.

Other info. - This species is common in the upper 2/3 of Missouri. Steyermark lists to varieties for the plant and they are still recognized by most authors.
Variety floribunda (Nutt.) Rydb. typically has 2-4 flowers per node and densely crowded racemes with flowers to 8mm long.
Variety tenuiflora has less crowded racemes, 1-2 flowers per node, and flowers to 6mm long. Both varieties can be hard to distinguish.

Photographs taken at the Settles Ford Conservation Area, Cass County, MO., 7-14-00.


Back