a common, cultivated, aquatic sedge (Cyperus alternifolius) having naked, triangular stems surmounted by an umbrellalike whorl of grasslike leaves and greenish spikelets
See umbrella plant in American Heritage Dictionary 4
noun
A widely cultivated, ornamental, robust sedge (Cyperus alternifolius) native to Madagascar and Mauritius, having long triangular leafless stems, a terminal umbrellalike cluster of grasslike leaves, and a compound umbel of spikelets with drooping rays.