Psoralea esculenta (PROSEA)

Plant Resources of South-East Asia Introduction

List of species

Psoralea esculenta Pursh

Family: Leguminosae

Synonyms

Pediomelum esculentum (Pursh) Rydberg.

Vernacular names

• Indian breadroot, prairie potato, Indian turnip (En, Am). Navet de prairie, pomme blanche, pomme de prairie (Fr).

Distribution

North America (southern Canada, United States), occasionally cultivated elsewhere.

Uses

The tubers were used by the American Indians like Irish potatoes. Flesh of the tuber dries quickly in the sun, producing a hard cake that can be stored safely for long periods. The cake is ground into a flour and can be used year-round to make bread or for thickening soups.

Observations

Rather stout erect, slightly branched, pubescent, perennial herb, up to 50 cm tall with roots thickening to potato-like tubers or to fusiform, large carrot-like tubers with white flesh. Leaves palmately compound, 5-foliolate; petiole usually much longer than blade; leaflets ovate or obovate, 2-6 cm × 0.8-2 cm. Inflorescence a dense, oblongoid spike, up to 10 cm long; flowers bluish. Fruit an oblongoid glabrous legume, up to 0.5 cm long, slightly wrinkled, enclosed in the calyx tube. Seed brown. P. esculenta occurs on marginal soils in prairies and plains. Propagation is from seed. It might be of interest for the drier highlands of South-East Asia. The tubers have a protein content of more than 7% (dry weight basis) and are said to have an agreeable flavour and texture. Other Psoralea species might have similar properties, e.g. P. patens Lindley and P. cinerea Lindley (from Australia; growing under adverse, dry conditions; tubers contain 5-7% protein on dry weight basis), P. hypogaea Nutt. (from central to southern United States; similar to P. esculenta but smaller). Tuber-bearing Psoralea species certainly deserve more scientific attention.

Selected sources

2, 30, 40, 62.

Authors

L.E. Groen, J.S. Siemonsma & P.C.M. Jansen