Desmodium purpureum des·mo·dium·purpureum uncommon noun 1. West Indian forage plant cultivated in southern United States as forage and to improve soil SynonymsbeggarweedDesmodium tortuosumDesmodium purpureum Related words Broader terms tick trefoil WordNet 2.1 (Princeton University). WordNet 2.1 Copyright Princeton University. All rights reserved.