Fuirena and Lipocarpha could be confused at a glance, but in Lipocarpha the spikelets are shorter (< 8 mm vs. 8 mm or longer). Fuirena often has excurved scale tips (except F. scirpoides and S. longa, which have no leaf blades or blades < 5 cm). In Lipocarpha the tips are generally not excurved. Fuirena has bristles in addition to the perianth lobes. Lipocaprha has no bristles. The Lipocarpha spikelet has just one flower, this associated with 1 or 2 (or 3 in species not in our region) leafy scales. There is 1 stamen.
1. Culms mostly > 10 cm (to 35 cm) tall; longest bract spreading; achenes elongate (> 3.5 X as long as wide); spikelets 2-8 mm long...L. microcephala (introduced Old World species)
1. Culms mostly < 10 (20) cm tall; longest bract erect; bracts < 3.5 X as long as wide; spikelets < 5 mm long; spikelets mostly 1-5 mm long...L. aristulata (not native but scattered adventively in Florida)