Montana Field Guide

Cicada milkvetch is a stemless (or nearly so) perennial herb with a simple or branched rootcrown and taproot. The pinnately compound leaves are 2-8 cm (1-3 in) long with 2-7 pairs of egg-shaped leaflets. Foliage is covered with silvery hairs that branch at the base and spread in opposite directions appressed to the surface of the leaf or stem (dolabriform). 4-9 flowers are borne on lax or ascending stalks arising from near the top of the rootcrown. The purplish, pea-like flowers have a slightly raised upper petal, 16-25 mm long, that is just barely longer than the others. The purplish calyx is 9-13 mm long and covered with white or black hairs. The brightly mottled, green and purple, inflated fruits are sparsely hairy and egg-shaped with a short, flattened beak and usually lay directly on the ground among the leaves.

Mature fruit in mid-June.

The combination of stemless habit, dolabriform hairs and mottled, inflated pods distinguish this species. A hand lens or microscope is required to observe the hairs.

Dry, often sandy soil of shrub steppe in the valleys.

POLLINATORS
The following animal species have been reported as pollinators of this plant species or its genus where their geographic ranges overlap: Bombus vagans, Bombus appositus, Bombus auricomus, Bombus bifarius, Bombus borealis, Bombus centralis, Bombus fervidus, Bombus flavifrons, Bombus huntii, Bombus mixtus, Bombus nevadensis, Bombus rufocinctus, Bombus ternarius, Bombus terricola, Bombus occidentalis, Bombus pensylvanicus, Bombus griseocollis, and Bombus insularis (Macior 1974, Thorp et al. 1983, Mayer et al. 2000, Colla and Dumesh 2010, Wilson et al. 2010, Koch et al. 2012, Miller-Struttmann and Galen 2014, Williams et al. 2014).