Oenothera biennis.

Botanical name: 

Oenothera biennis Linn. Onagraceae. Evening Primrose. German Rampion.

Northeastern America. This plant was formerly cultivated in English gardens for its edible roots, which, when boiled, are wholesome and nutritious. In Germany the roots are used as scorzonera and the young shoots in salads. The roots are sweet to the taste, somewhat resembling parsnips. The roots may be used as scorzonera, but the plant is cultivated in France only as a curiosity. It is said by Loudon to be cultivated in Germany, and, in Carniola, the roots are eaten in salad. It first reached Europe in 1614. It is given by Burr for American gardens in 1863, under the name German Rampion.

Sturtevant's Edible Plants of the World, 1919, was edited by U. P. Hedrick.