Rhizomes to 20 cm × 10 mm. Culms 1-3 m × 5-10 mm. Leaves: blades flat to broadly V-shaped, 5-11 mm wide, margins and midvein abaxially harshly scabrous with teeth visible to unaided eye. Inflorescences terminal (or lateral and terminal), 30-50 cm; 1st, 2d, 3d, and some 4th order branches, branches slightly flexuous. Spikelets in groups of 2-3(-6), narrowly ellipsoid to lanceolate; floral scales 5-6, the proximal chestnut brown, ovate to oblong-lanceolate, 2.5-3 × 2 mm, midvein conspicuous, lateral veins weak; stamens 2; anthers 2 mm, connective apices 0.1-0.2 mm; styles 2-2.5 mm; stigmas 1-1.5 mm. Achenes light greenish brown, ovoid, 2 × 1 mm, glossy, base vaguely 3-lobed, truncate, not flared or discoid, apex acute, irregularly rugulose longitudinally. Fruiting spring-summer. Coastal brackish and fresh marshes; 0-100 m; Ala., Ark., Fla., Ga., La., Miss., N.C., S.C., Tex., Va.; Mexico; West Indies; Central America; n South America. Cladium jamaicense is important as the dominant species in much of the Florida Everglades (K. K. Steward and W. H. Ornes 1975).
Culms stout, 5-10 mm thick, to 3 m; lf-blades 5-10 mm wide, very rough on the margins and along the midrib beneath, flat or folded in the middle, becoming trigonous distally; infl decompound, 3-8 נ1-3 dm; achene contracted at base. Swamps and shallow water; near the coast from se. Va. to Fla., Tex., and W.I.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.