Lewis & Short

hĭbiscum (also ĕbiscum, Scrib. 80; 82; and hĭbiscus, i, f., Serv. Verg. E. 2, 30), i, n., = ὶβίσκος, the marsh-mallow, Althaea officinalis, Linn.; Plin. 20, 4, 14, § 29; 19, 5, 27, § 89; Verg. E. 10, 71: haedorumque gregem viridi compellere hibisco, i. e. with a marsh-mallow twig, id. ib. 2, 30.