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... (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...2

2.  Inner scale 0.5-0.8 mm long; spikelets mostly 1-5 mm long... (not native but scattered adventively in Florida)

2.  Inner scale vestigial (< 0.2 mm long) or absent; spikelets mostly < 3 mm long..

Lipocarpha maculata could turn up in our area.  It is nearby, with cylindric succulent bracts and compact sessile spikelets.  It is (if here) the only species in our area with spikes often > 5 mm long (usually < 5 mm), anthers 0.5 mm long (vs. < 0.25 mm), and 3 (vs. 2) stigmas.