Potamogeton gramineous po·ta·mo·getongramineous uncommon noun 1. of Europe (except the Mediterranean area) and the northern United States Synonymsvariously-leaved pondweedPotamogeton gramineous Related words Broader terms pondweed Parts Potamogeton WordNet 2.1 (Princeton University). WordNet 2.1 Copyright Princeton University. All rights reserved.