chufa(n = noun.plant) cyperus esculentus, earth almond, ground almond, rush nut, yellow nutgrass - European sedge having small edible nutlike tubers;
is a kind of sedge
is a member of cyperus, genus cyperus

   A sedgelike plant (Cyperus esculentus) producing edible tubers, native about the Mediterranean, now cultivated in many regions; the earth almond. [1913 Webster]