C. alopecuroides is a large sedge is rarely found in wet, disturbed sites in Hillsborough, Polk, and Hardee counties. It is native to the Old and New World tropics. Foxtail flatsedge blooms in the summer (Wunderlin, 2003).
C. alopecuroides grows up to twelve feet tall, with bracts up to six feet long! It has broad bracts and leaf blades and a branched inflorescence with spikes of densely clustered golden-brown spikelets. Its leaf margins are serrated and sharp. This species is widely distributed in the tropics of the Old World where it may form extensive stands and floating mats.
For brief control information, see Efficacy of Herbicide Active Ingredients Against Aquatic Weeds by K. Langeland, M. Netherland, and W. Haller.