Cenchrus spinifex |
Cenchrus brownii |
|
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coastal sandbur, common sandbur |
green sandbur, slimbristle sandbur |
|
Habit | Plants annual or perennial but short-lived; tufted. | Plants annual. |
Culms | 30-100 cm, geniculate. |
25-100 cm, erect or decumbent. |
Sheaths | compressed, glabrous or sparsely pilose; ligules 0.5-1.4 mm; blades 3-28 cm long, (1)3-7.2 mm wide, glabrous or sparsely long-pilose adaxially. |
slightly compressed; ligules 0.6-1.3 mm; blades 6-30 cm long, 0.4-1.1 cm wide, adaxial surfaces glabrous or sparsely pilose. |
Panicles | 3-5(8.5) cm; fascicles 5.5-10.2 mm long, 2.5-5 mm wide, imbricate, ovoid to globose, glabrous or sparesely to moderately pubescent; outer bristles, when present, mostly flattened; inner bristles 8-40 (rarely more), 2-5.8 mm long, 1-2 mm wide, fused at least 1/2 their length, forming a distinct cupule, the distal portions usually diverging from the cupule at multiple, irregular intervals, sometimes diverging at more or less the same level, ciliate at the base, pubescent, stramineous to mauve or purple, flattened. |
4-15 cm; rachis internodes 0.8-1.7 mm; fascicles 5-8 mm long, 2-A.5 mm wide, imbricate, globose, villous at the base, tawny; outer bristles 5-25, the majority equaling or slightly exceeding the inner bristles but narrower and terete, arising in a whorl at the base of the fascicles; inner bristles 4-10, 2-4 mm long, 0.6-1.8 mm wide at the base, flattened, not grooved, erect or interlocking at maturity, fused for 1/3 their length or more, forming a globose cupule. |
Spikelets | 2-4 per fascicle, 3.5-5.9 mm, glabrous. |
2-3 per fascicle, 3-6 mm. |
Caryopses | about 2.5 mm long, 1-2 mm wide, ovoid. |
1.9-2.6 mm long, 0.8-1.9 mm wide, ovoid. |
Lower | glumes 1-3.3 mm; upper glumes (2.8)3.5-5 mm, 5-7-veined; lower florets sometimes staminate; lower lemmas 3-5(5.9) mm, 5-7-veined; lower paleas sometimes reduced or absent; anthers 1.3-1.6 mm; upper lemmas 3.5-5(5.8) mm; anthers 0.5-1.2 mm. |
glumes 0.5-2.5 mm; upper glumes 2.2-4.9 mm, 3-5-veined; lower lemmas 3-5.5 mm; upper florets 3.6-5.4 mm; anthers 0.8-2.3 mm. |
2n | = 34 (32). |
= 34. |
Cenchrus spinifex |
Cenchrus brownii |
|
Distribution |
AL; AR; AZ; CA; DC; FL; GA; KS; KY; LA; MA; MD; ME; MS; NC; NM; NV; OK; SC; TN; TX; VA; VT; PR; Virgin Islands
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AL; FL; GA; NC; TX; PR; Virgin Islands |
Discussion | Cenchrus spinifex is common in sandy woods, fields, and waste places throughout the southern United States and southwards into South America. It may be more widespread than shown in the northern portion of the contiguous United States because it has often been confused with C. tribuloides. Cenchrus spinifex differs from C. tribuloides in its glabrous or less densely pubescent fascicles, narrower inner bristles, and larger number of bristles. It has also been confused with C. longispinus but differs in having shorter spikelets, fewer bristles overall, wider inner bristles, and outer bristles that are usually flattened rather than usually terete. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Cenchrus brownii is native to sandy waste places and forest borders. It occurs infrequently on the coastal plain of the southeastern United States, but is common through the Caribbean, Central America, and the northern coast of South America. It has also been introduced to other parts of the world. The record from Texas may represent an introduction; only one specimen is known from the state. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 25, p. 533. | FNA vol. 25, p. 531. |
Parent taxa | Poaceae > subfam. Panicoideae > tribe Paniceae > Cenchrus | Poaceae > subfam. Panicoideae > tribe Paniceae > Cenchrus |
Sibling taxa | ||
Synonyms | C. pauciflorus, C. incertus, C. bambusoides | |
Name authority | Cav. | Roem. & Schult. |
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