Cyperus involucratus Rottb.
Cyperus alternifolius auct. non L.
Cyperus alternifolius L. ssp. flabelliformis (Rottb.) Kük.
Cyperus flabelliformis Rottb.
Probably native to Madagascar, the umbrella sedge has become naturalized throughout much of Africa and southern North America. It can become invasive in wet habitats. It is closely related and similar in appearance to the Egyptian papyrus plant.
Identification: These plants most prefer wet, boggy habitats. They grow in dense clumps of triangular stems 24-72" (60-182 cm) high. Stems are leafless except at the bottom, where there are some inconspicuous basal leaves, and at the tops, where are starlike array of long, narrow grasslike leaves spreads extend in a circle around the stem. Each leaf is 6-15" (15-38 cm) × ½" (1.3 cm). At the center there is a cluster of 15-25 greenish spikelet flowers. Individual spikelets are up to ⅜" (9.5 mm) long.
Cyperus involucratus on floridata.com
Cyperus involucratus on Forest and Kim Starr’s Starr Environmental site
Cyperus involucratus on Calflora
Cyperus involucratus on SEINet—the Southwest Environmental Information Network
Cyperus involucratus from the Jepson Manual
Cyperus involucratus description by Thomas H. Kent, last updated 12 Oct 2018.
Range: Zones 8-11: