Cyperus surinamensis Rottb.

  • Authority

    Acevedo-Rodríguez, Pedro & collaborators. 1996. Flora of St. John, U.S. Virgin Islands. Mem. New York Bot. Gard. 78: 1-581.

  • Family


  • Scientific Name

    Cyperus surinamensis Rottb.

  • Description

    Species Description - Perennial, 0.5-1.2 m tall; rhizome short; culms cespitose or arising at short intervals along the rhizome, 2-6, 3-angled, (1-)2- 4(-4.5) mm wide, retrorsely scabrous to nearly smooth, glabrous, sheathing base of culm (3-)4-7(-12) mm wide. Leaves 3-9; blades flat or sometimes laterally compressed, (12-)25-45(-65) cm long, 2-4(-6.5) mm wide, with scabrous or scaberulous margins, acuminate at apex; sheaths finely veined, septate, pale green to brownish, glabrous, eligulate, the inner band finely nerved. Inflorescence a compound, umbel-like corymb, (3-)5-18 cm diam.; involucral bracts 4-7, leaflike, flat, the lower ones to 40 cm long, 2-5 mm wide, remotely scabrous to smooth on margins and midvein beneath, acuminate at apex; rays (9-) 14- 16(-20), very unequal, obscurely 3-angled, cylindrical or compressed, smooth, finely ribbed, the primary ones to 15 cm long, 0.5-1 mm wide, stiff, ascending, the secondary ones 3-6, 1-2 cm long, divergent to reflexed at maturity, the lateral rays flexuous (just below the base of the central, sessile spike), divergent to reflexed at maturity; spikes broadly ovate to hemispherical, or subrounded, 0.7-1.5 x 0.7-1.8 cm; spikelets (10-)25-50(-90) per umbel, ovate, oblong-ovate to oblong-lanceolate, distinctly flattened, (3-)4-8(-12) x 1.8-2 mm; rachilla wingless, to 2 cm long, with (9-) 11-31 (-45) flowers; scales oblong-ovate to lanceolate, curvate-keeled, 1.2-1.5 x 0.7-0.9 mm , membranous, minutely reticulate, pale yellow, pale brown or reddish brown, the keel greenish, 3-nerved, 2-keeled near base, short-mucronate at apex, sometimes scabrous above. Stamen 1, the anther 0.7-0.8 mm long; style 3-branched to below the middle. Achene 3-angled, narrowly ovate-ellipsoid to narrowly oblong-ellipsoid, 0.8-0.9 x 0.3 mm , acute and apiculate at apex, brown to reddish brown, shiny, papillate, indistinctly rugulose, with flat to slightly convex faces.

  • Discussion

    Cyperus formosus Vahl, Enum. PL 2: 327. 1806. Cyperus surinamensis var. formosus (Vahl) Kiik., Repert. Spec. Nov. Regni Veg. 32: 74. 1933. Cyperus surinamensis var. lutescens Boeck., Linnaea 35: 555. 1868.

    Cultivated species: Cyperus involucratus Rottb., the umbrella-plant, has been cultivated on St. John but has not become naturalized

  • Distribution

    Occasional in permanent shallow pools. Herman Farm (W457), Catherinesberg (A5070). Also on St. Thomas; southern United States to South America and the West Indies.

    West Indies| Saint Thomas Virgin Islands of the United States South America| West Indies|