| Noun | 1. | spike rush - a sedge of the genus Eleocharis sedge - grasslike or rushlike plant growing in wet places having solid stems, narrow grasslike leaves and spikelets of inconspicuous flowers Eleocharis, genus Eleocharis - sedges having dense spikes of flowers and leaves reduced to basal sheaths Chinese water chestnut, Eleocharis dulcis, water chestnut - Chinese sedge yielding edible bulb-shaped tubers Eleocharis acicularis, hair grass, needle rush, needle spike rush, slender spike rush - fine-leaved aquatic spike rush; popular as aerator for aquariums creeping spike rush, Eleocharis palustris - cylindrical-stemmed sedge |