Flora of the Hawaiian Islands
Monocotyledon Literature for Echinochloa colona
Wagner et al., 1990, 1999; Lorence & Wagner, 2019.
   Poaceae -- The Grass Family Bibliography
      Echinochloa colona

Common name(s): jungle-rice
General Information
DistributionApparently native to the Paleotropics, but now widely distributed.In the Hawaiian Islands, naturalized on Ni`ihau, Kaua`i, O`ahu, Moloka`i, Lana`i, Maui, Kaho`olawe, Hawai`i.

Annual; culms tufted, usually reddish purple, erect, ascending or decumbent at base, sometimes rooting at proximal nodes, 20‒60 cm tall, sometimes nodes conspicuously swollen and usually geniculate, compressed, proximal internodes often exposed.
Leaves with sheath 3‒8 cm long, compressed, keeled, glabrous; ligule absent; blade green or sometimes with transverse purple bands, flat, 4‒15 cm long, 3‒8 mm wide, often undulate, margin occasionally scabrous, apex acute.
Inflorescences paniculate, usually 5‒10(‒15) cm long, green or purple tinged, racemes 5‒9, 1‒2 cm long, the proximal ones to 1 cm apart, distal ones crowded, rachis scaberulous, pedicel short, scaberulous. Spikelets crowded, usually in ca. 4 rows, (1.5‒)2.5‒3 mm long, acute to cuspidate, rarely with a subulate point to 1 mm long; glumes ovate, hispidulous, apex acute, first glume 1.2‒1.5 mm long, 3-veined, second glume 2.5‒3 mm long, 7-veined; first lemma similar to second glume, first palea ovate, ca. 2 mm long, glabrous; second lemma broadly ovate, ca. 2 mm long, glossy.
Caryopses whitish, broadly ovate, 1.7‒2 mm long, flat on 1 side.
2n = 30, 36, 48, 52, 54, 56, 72, 96, 108, 130.
Warren Wagner