Cenchrus echinatus |
Cenchrus |
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burgrass, common sandbur, field sandbur, konpeito-gusa, sandburr, se mbulabula, southern sandbur, vao tui tui |
bur-grass, hedgehog-grass, sand-bur |
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Habit | Plants annual. | Plants annual or perennial. | ||||||||||||||||||||||||||||
Culms | 20-100 cm, ascending from a geniculate base. |
5-200 cm, erect or decumbent, usually geniculate; nodes and internodes usually glabrous. |
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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. |
open, usually glabrous; ligules membranous, ciliate, cilia as long as or longer than the basal membrane; blades flat or folded, margins cartilaginous, scabridu-lous. |
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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. |
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Inflorescences | terminal, spikelike panicles of highly reduced branches termed fascicles ("burs"); fascicles consisting of 1-2 series of many, stiff, partially fused, usually retrorsely scabridulous to strigose, sharp bristles surrounding, sometimes almost concealing, 1-4 spikelets; outer (lower) bristles, if present, in 1 or more whorls, terete or flattened; inner (upper) bristles usually strongly flattened, fused at least at the base and forming a disk, frequently to more than 1/2 their length and forming a cupule; disarticulation at the base of the fascicles. |
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Spikelets | 2-3(4) per fascicle, 4.8-7 mm. |
sessile, with 2 florets; lower florets usually sterile; upper florets bisexual. |
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Caryopses | ovoid, 1.2-3.2 mm long, 1.3-2.2 mm wide. |
obtrulloid. |
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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. |
glumes ovate, scarious, glabrous, 1-veined, acute to acuminate; upper glumes and lower lemmas ovate, 3-9-veined; lower paleas equaling the lemmas, tawny or purplish; upper lemmas and paleas subequal, indurate, ovate, obscurely veined, acuminate. |
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x | = 17. |
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2n | = (34), 68. |
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Cenchrus echinatus |
Cenchrus |
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Distribution |
AL; AZ; CA; DC; FL; GA; LA; MD; MS; NC; NM; OK; SC; TX; VA; HI; PR; Virgin Islands
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AL; AR; AZ; CA; CO; CT; DC; DE; FL; GA; IA; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; MT; NC; ND; NE; NH; NJ; NM; NV; NY; OH; OK; OR; PA; RI; SC; SD; TN; TX; UT; VA; VT; WA; WI; WV; WY; HI; PR; BC; ON; QC; Virgin Islands |
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Discussion | Cenchrus echinatus grows in disturbed areas throughout the coastal plain and piedmont of the southern United States, Mexico, Central and South America, and, as an unwelcome introduction, elsewhere. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Cenchrus has about 16, primarily tropical species, most of which are readily (and painfully) recognized by their spiny fascicles. Most of its species differ from those of Pennisetum in having retrorsely scabrous or strigose inner bristles that are fused to well above their bases. The species are generally considered to be undesirable weeds. Seven species of Cenchrus are native to the Flora region. The eighth species in this treatment was collected once in Westchester County, New York, but does not appear to have become established in the Flora region. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 25, p. 531. | FNA vol. 25, p. 529. | ||||||||||||||||||||||||||||
Parent taxa | Poaceae > subfam. Panicoideae > tribe Paniceae > Cenchrus | Poaceae > subfam. Panicoideae > tribe Paniceae | ||||||||||||||||||||||||||||
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Synonyms | C. echinatus var. hillebrandianus | |||||||||||||||||||||||||||||
Name authority | L. | L. | ||||||||||||||||||||||||||||
Web links |
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