Echinochloa colonum (L.) Link subsp. colonum

synonyms: Echinochloa colona, Panicum colonum


jungle-rice


Info

Subfamily: Panicoideae
Genus etymology: Echinochloa = "hedgehog grass" [Greek] refering to the awned florets which are tightly arranged resembling a hedgehog
Species etymology: colonum = "of cultivated fields" [Latin] refering to the habitat
Photosynthetic type: C4 (warm season)
Nativity: naturalized - accidental
First recorded in Hawaiʻi: 1835

Map

 Distribution of Echinochloa colonum subsp. colonum in Hawaiʻi.
 Distribution of Echinochloa colonum subsp. colonum in Hawaiʻi.

Inflorescence

Echinochloa colonum subsp. colonum Inflorescence
Echinochloa colonum subsp. colonum Inflorescence
Echinochloa colonum subsp. colonum Inflorescence
Echinochloa colonum subsp. colonum Inflorescence
Echinochloa colonum subsp. colonum Inflorescence
Echinochloa colonum subsp. colonum Inflorescence
Echinochloa colonum subsp. colonum Inflorescence

Plant

Echinochloa colonum subsp. colonum Plant
Echinochloa colonum subsp. colonum Plant

Habit

Echinochloa colonum subsp. colonum Habit

Spikelets

Echinochloa colonum subsp. colonum Spikelets
Echinochloa colonum subsp. colonum Spikelets
Echinochloa colonum subsp. colonum Spikelets
Echinochloa colonum subsp. colonum Spikelets
Echinochloa colonum subsp. colonum Spikelets
Echinochloa colonum subsp. colonum Spikelets
Echinochloa colonum subsp. colonum Spikelets

Description

Annual; culms 10–100 cm. high, erect or ascending. Leaf-blades 5–30 cm. long, 2–8 mm. wide, occasionally marked with purple bars; ligule absent; sheaths glabrous. Inflorescence typically linear, 1–15 cm. long, the racemes neatly 4-rowed, seldom over 3 cm. long, simple, commonly ± 1/2 their length apart and appressed to the axis but sometimes subverticillate and spreading (rarely congested). Spikelets ovate-elliptic to subglobose, 1.5–3 mm. long, pubescent; lower floret ♂ or barren, acute to cuspidate (rarely with a subulate point up to 1 mm. long); upper lemma 2–3 mm. long. Fig. 134.
(Description source: Clayton, W.D. & Renvoize, S.A. 1982. Flora of Tropical East Africa. Gramineae (Part 3). A.A. Balkema, Rotterdam. 448 pp. )

Annual. Culms 10–150 cm. high, erect or ascending; ligule absent. Inflorescence 1–20 cm. long, typically linear; racemes up to 3 (rarely 5) cm. long, neatly 4-rowed, simple commonly c. 1/2 their length apart and appressed to the axis but sometimes subverticillate and spreading, rarely congested. Spikelets 1.5–3(3.5) mm. long, subglobose to ovate-elliptic, pubescent to hispidulous, often purple tinged. Inferior floret male or barren, its lemma acute to cuspidate (rarely mucronate). Superior lemma 2–3 mm. long.
(Description source: Launert, E. & Pope, G.V. (eds.). 1989. Flora Zambesiaca. Volume 10. Part 3. Kew, London. 152 pp. )

Plants annual; erect or decumbent, cespitose or spreading, rooting from the lower cauline nodes. Culms 10-70 cm; lower nodes glabrous or hispid, hairs appressed; upper nodes glabrous. Sheaths glabrous; ligules absent, ligule region frequently brown-purple; blades 8-22 cm long, 3-6(10) mm wide, mostly glabrous, sometimes hispid, hairs papillose-based on or near the margins. Panicles 2-12 cm, erect, rachises glabrous or sparsely hispid; primary branches 5-10, 0.7-2(4) cm, erect to ascending, spikelike, somewhat distant, without secondary branches, axes glabrous or sparsely hispid, hairs 1.5-2.5 mm, papillose-based. Spikelets 2-3 mm, disarticulating at maturity, pubescent to hispid, hairs usually not papillose-based, tips acute to cuspidate. Lower glumes about 1/2 as long as the spikelets; upper glumes about as long as the spikelets; lower florets usually sterile, occasionally staminate; lower lemmas unawned, similar to the upper glumes; lower paleas subequal to the lemmas; upper lemmas 2.6-2.9 mm, not or scarcely exceeding the upper glumes, elliptic, coriaceous portion rounded distally, passing abruptly into a sharply differentiated, membranous, soon-withering tip; anthers 0.7-0.8 mm. Caryopses 1.2-1.6 mm, whitish; embryos 63-83% as long as the caryopses. 2n = 54.
(Description source: Barkworth, M.E., Capels, K.M., Long, S. & Piep, M.B. (eds.) 2003. Flora of North America, north of Mexico. Volume 25. Magnoliophyta: Commelinidae (in part): Poaceae, Part 2. Oxford University Press, New York. 783 pp http://floranorthamerica.org/Echinochloa_colona )

Annuals; culms tufted, usually reddish purple, erect, ascending or decumbent at base, sometimes rooting at lower nodes, 20-60 cm tall, sometimes nodes conspicuously swollen and usually geniculate, compressed, lower internodes often exposed. Sheaths 3-7 cm long, compressed, keeled, glabrous; ligule absent; blades green or sometimes with transverse purple bands, flat, 4-10 cm long, 3-8 mm wide, often undulate, margins occasionally scabrous, apex acute. Inflorescences paniculate, usually 5-10(-15) cm long, green or purple tinged, racemes several, 1-2 cm long, the lower ones up to 1 cm apart, the upper ones crowded, rachis scaberulous, pedicels short, scaberulous; spikelets crowded, usually in ca. 4 rows, (1.5-)2.5-3 mm long, acute to cuspidate, rarely with a subulate point up to 1 mm long; glumes ovate, hispidulous, apex acute, first glume 1.2-1.5 mm long, 3-nerved, second glume 2.5-3 mm long, 7-nerved; first lemma similar to second glume, first palea ovate, ca. 2 mm long, glabrous; second lemma broadly ovate, ca. 2 mm long, glossy. Caryopsis whitish, broadly ovate, 1.7-2 mm long, flat on one side. [2m = 30, 36, 48, 52, 54, 56, 72, 96, 108, 130]
(Description source: O’Connor, P.J. 1990. Poaceae, pp. 1481–1604. In: Wagner W.L., Herbst D.R. & Sohmer S.H. (eds.)., Manual of the flowering plant of Hawaiʻi. Vol. 2. University of Hawaii Press & Bishop Museum Press, Honolulu )