Neat spike-rush has ovoid, acutish, spikelets, 1.5-4.5mm long and 1.5-3mm wide, that are loosely flowered. Its anthers are 0.5-0.7mm long, bristles are absent. Its achenes are pale yellow, becoming orange, sharply 3-angled, very minutely wrinkled, 0.7-0.8mm long, and persistent. Tubercles are a depressed saucer with centralapiculation. Its culms are tufted or scattered, delicately capillary, 4-angled, and 2-10cm tall. Basal sheaths are close, greenish or yellowish, and scarcely darkened at summit.
It can be distinguished from other Eleocharis species by the combination of spikelets that are wider than the stem and achenes, which are 3-angled and dark yellow or orange.