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Cenchrus
See list of 2 species in this genusThe bur-like fascicles (in our species) of Cenchrus have two cycles of bristles. The outer bristles are positioned closer to the pedicel, are usually retrorsely oriented, and are terete to flattened in cross-section (depending on the species). The inner bristles are fused into a cupule with the apical portions distinct, vary from spreading to erect, and are flattened in cross-section. Reports of C. tribuloides from New England were based on collections of C. longispinus (mostly) and C. spinifex. Reference: Stieber and Wipff (2003).
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1a. Bur-like fascicles with 45–75 bristles [Fig. 204], 8.3–11.9 mm long, the outer bristles terete, the inner bristles 0.5–0.9 (–1.4) mm wide at the base; carypsis 1.5–2.6 mm wide
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1b. Bur-like fascicles with 8–40 bristles, 5.5–10.2 mm long, the outer bristles absent or present and then usually flattened, the inner bristles 1–3 mm wide; caryopsis 1–2 mm wide
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Each photo represents one species in this genus.