Common names: spikerush

Family: Cyperaceae

Could be confused with: Equisetum, Isoetes, Juncus, Triglochin.

Native distribution: Cosmopolitan.

Species commonly cultivated:
Eleocharis acicularis (L.) Roem.& Schult. (Cosmopolitan)
E. dulcis (Burm.) Hensch. (Cosmopolitan)
E. vivipara Link (southern U.S.)

Adventive distribution: Eleocharis acicularis, E. dulcis and E. palustris (L.) R. Br. are so widely distributed around the world that it is difficult to determine in what parts of this range they are native.

Weed status: Eleocharis acicularis, E. dulcis and E. palustris are considered serious weeds of rice fields and waterways in numerous countries around the world.

Habit: Submersed, emergent, rhizomatous.

Brief description: Annual or perennial sedge. Rhizome slender, extending horizontally beneath substrate, producing erect stems at regular intervals. Roots sometimes bearing storage tubers. Stem typically cylindrical or angled, often jointed (septate). Leaves reduced to membranous basal leaf sheaths. Inflorescence a solitary, terminal spikelet; spikelets few- to many-flowered, not subtended by bracts; outer bracts spirally arranged. Flowers bisexual; perianth reduced to bristles with 2-3 stamens. Dispersal by seeds or rhizome fragments.

Natural habitat: Common in shallow, sandy waters of all water bodies; also on wet ground.

Additional comments: A very large and morphologically diverse genus of over 180 species worldwide. A few species are used in aquaria or ponds. Eleocharis dulcis (‘water chestnut’) is grown commercially and the root tubers serve as a food source.