Eleocharis parvula is a species of spikesedge known by the common names dwarf spikerush, small spikerush and hairgrass in aquaria. It has a circumboreal distribution, growing throughout Eurasia and North America, into Central America. It is a plant of brackish and saltwater habitat, such as marshes and mudflats. It is a perennial herb growing tufts of spongy, compressible stems not more than 10 centimeters tall. The plant grows from a tuber which is J-shaped or horseshoe-shaped,...