Umbrella-plant definition

A sedge (Cyperus involucratus syn. C. alternifolius) native to Madagascar and the Mascarene Islands and widely cultivated as an ornamental, having leafless stems with a terminal umbrellalike cluster of long narrow bracts.

Any of various other plants having parts with an umbrellalike form.

A common, cultivated, aquatic sedge (Cyperus alternifolius) having naked, triangular stems surmounted by an umbrellalike whorl of grasslike leaves and greenish spikelets.