MANUAL OF THE GEASSES OF THE UNITED STATES 



709 



Body of bur globose, 5 mm wide or more, not tapering at base; plants annual. 

 Burs, including spines, 7 to 8 mm wide, finely pubescent. 



6. C. PAUCIFLORUS. 

 Burs, including spines, 10 to 15 mm wide, densely woolly. 



7. C. TRIBULOIDES. 



1. Cenchrus rayosuroides H. B. K. (Fig. 1587.) Stout glaucous 

 woody perennial ; culms erect from an often decumbent base, 1 to 1.5 m 



Figure 1587. — Cenchrus myosuroides. Bur, two 

 views of spikelet, and floret, X 5. (Leon 835, 

 Cuba.) 



Figure 1588. — Cenchrus viridis. Bur, two views of 

 spikelet, and floret, X 5. (Type.) 



tall, brandling below; blades 5 to 12 mm wide; raceme 10 to 25 cm 

 long, strict, erect, dense; burs 1-flowered, about 5 mm wide, the bristles 

 united at the base only, the outer shorter, the inner about as long as 

 the spikelet; spikelet 4.5 to 5.5 mm long. % — Moist sandy open 

 ground or scrubland near the coast, Georgia and Florida, southern 

 Louisiana and southern Texas; tropical America. 



Cenchrus barbatus Schum. Annual; culms 30 to 100 cm tall; 

 raceme 8 to 10 cm long, the burs usually 2-flowered, 4 to 6 mm long, 



Figure 1589. — Cenchrus echinatus. Bur, two views of spikelet, and floret, 



9379, Jamaica.) 



X 5. (Hitchcock 



the outer row of bristles short, spreading, the inner flattened, rigid, 

 erect. © (C. catharticus Del.) — Ballast, Mobile, Ala.; native of 

 Nubia. 



2. Cenchrus viridis Spreng. (Fig. 1588.) Annual, mostly erect, 

 30 to 100 cm taU; blades thin, flat, lax, 6 to 12 mm wide; raceme 4 to 

 10 cm long, dense; burs depressed globose, about 4 mm high, the outer 

 bristles numerous, very slender, the inner somewhat exceeding the 

 body, the lobes interlocking at maturity; spikelets usually 3. o — 

 Open ground, often a weed in waste places, Florida Keys; tropical 

 America at low altitudes; introduced in Malaysia. 



