Petalostemon purpureus (Vent.) Rydb. - Purple Prairie Clover
Family - Fabaceae
Stems - To -1m tall, simple or branching above, Multiple from base, erect to ascending, glabrous to densely villous, herbaceous.
Leaves - Alternate, odd-pinnate, stipulate, to -5cm long. Stipules linear, 5mm long. Leaflets typically 3-5, linear to linear-oblong, involute, opposite, -2cm long, 2mm broad, entire, sparse villous, glandular punctate below, subsessile or on very short petiolule to .7mm long. Petiole punctate glandular, villous, with adaxial groove.
Inflorescence - Dense, indeterminate,
cylindrical spikes to 7cm tall, 1.2cm in diameter, terminating stems.
Flowers - Petals purplish-pink, clawed, connected to staminal column (column to 3mm long, white, glabrous), 4-6mm long, 1mm broad. Claws to -4mm long. Stamens 5, monodelphous. Filaments 5-6mm long, purplish. Anthers .9mm long, orange. Style 8-9mm long, white to pinkish, mostly glabrous but bearded below, filiform. Ovary 1.4mm long, pubescent at apex. Calyx tube to 3mm long, white, dense pubescent, 5-lobed. Lobes green acute, 1.2mm long, equal, dense pubescent.
Young flowers with stamens not yet expanded.
Flowering - June - September.
Habitat - Prairies, glades, open woods, roadsides, railroads.
Origin - Native to U.S.
Other info. - At first glance the flowers and spikes of this plant appear somewhat uncharacteristic of most plants in the bean family. Closer examination reveals that indeed the plant is properly placed.
Photographs taken at Alley Spring, MO., 6-13-03.