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Info
Subfamily: Panicoideae
Genus etymology: Cenchrus = "millet" [Greek]. However this is a misnomer, the only millet species in this genus is C. americanus, and this was treated as Pennisetum when Cenchrus was erected.
Species etymology: echinatus = "hedge hog" [Latin] refering to the spines on the burs
Photosynthetic type: C4 (warm season)
Nativity: naturalized - accidental
First recorded in Hawaiʻi: 1864
Map
Inflorescence
Plant
Habit
Spikelets
Description
Plants annual. Culms 20-100 cm, ascending from a geniculate base. Sheaths from shorter than to equaling the internodes, compressed; ligules 0.7-1.7 mm; blades 4-18(35) cm long, 2-10(14.2) mm wide, adaxial surfaces sparsely pilose, hairs papillose-based. Panicles 2.5-12 cm; rachis internodes 2-4 mm; fascicles 5-10 mm long, 3.5-6(6.3) mm wide, imbricate; outer bristles 10-20, terete, the majority no more than 1/2 as long as the inner bristles; inner bristles 2-5 mm long, 0.6-1.5 mm wide, flattened, not grooved, mostly erect, fused for at least 1/2 their length into a globose cupule, sometimes interlocking at maturity, shortly pubescent, often purple at maturity. Spikelets 2-3(4) per fascicle, 4.8-7 mm. Lower glumes 1.3-3.4 mm; upper glumes 3.8-5.7 mm, 3-7-veined; lower lemmas 4.5-6.5 mm; upper florets 4.7-7 mm; anthers 0.8-2.4 mm. Caryopses ovoid, 1.2-3.2 mm long, 1.3-2.2 mm wide. 2n = (34), 68.
(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/Cenchrus_echinatus )
Annuals; culms decumbent at base, 25- 70 cm tall, profusely branched, compressed, usually geniculate, often reddish at nodes and lower portion, usually scabrous for 3-4 cm below panicle, otherwise glabrous. Sheaths 4-7 cm long, glabrous or scaberulous, with a conspicuous whitish collar, compressed; ligule densely ciliate, ca. 1 mm long; blades flat, 5-18 cm long, 3-9 mm wide, striate, midrib conspicuous, upper surface scabrous and sometimes sparsely pilose at base, lower surface glabrous or scabrous near apex. Inflorescences composed of racemes 3-7 cm long, rachis zigzag with scabrous angles; burs usually dark red to purple, readily deciduous, wellspaced, broadly ovoid, 4-7 mm long and as wide or wider, bur receptacle obconical, 1-2 mm long, tomentulose, lobes of bur deeply cleft, short-tomentulose, outer series of bristles 2-3 mm long, retrorsely scabrous, inner series of bristles rather flattened, short-pilose at base, retrorsely scabrous toward apex; spikelets 3-5 per bur, 4-6 mm long; first glume membranous, scale-like, indistinctly 1-nerved, 1-1.5 mm long, glabrous, second glume membranous, 4-4.5 1513 mm long, prominently 3-nerved, minutely scaberulous, apex acute; sterile lemma 4.5- 6 mm long, 5-nerved, scaberulous, apex acuminate, sterile palea as long as sterile lemma, 2-nerved, submembranous, glabrous, apex attenuate; fertile lemma ca. 5 mm long, 5-nerved, nerves scaberulous near apex, apex attenuate; palea as long as lemma, 2-nerved, glabrous, apex acuminate. Caryopsis broadly ovate, usually flattened ventrally, rounded dorsally, 3-4 mm long. [2n = 34, 68.]
(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 )