ERIANTHUS (from erion, wool, and anthos, a flower; referring to the tuft of hairs at the base of each spikelet). SYN. Ripidium. ORD. Gramineae. This genus comprises about a dozen species of hardy and half-hardy grasses, found in most warm regions. ERIANTHUS Ravennae (Ravenna)* is a very handsome and stately hardy grass, from South Europe. Its foliage forms dense tufts in a light soil; the flowering stems sometimes attain a height of from 5ft. to 6 1/2ft., but these are only produced in very warm summers. It is an excellent plant for the sub-tropical garden.