64 



CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



slender axis flexuous, scabrous; burs 3.5 to 5 mm. wide (excluding the spines), 

 somewhat tapering to the base, glabrous ; spines spreading or reflexed, all 

 glabrous and flat, broadened at base, the lowest ones slender, shorter, some of 

 the upper ones commonly 5 to 6 mm. long ; body of the bur usually with 1 or 2 

 deep clefts, the lobes about 8, erect or spreading, 6 to 8 mm. long, ciliate at the 



. 1 : ; m 



Fig. 14. — Crnehrus graoillimua. From Ihe type specimen. 



base, rigid and spinelike ; spikelets 2 or 3, 5.5 to 7 mm. long, about 1.5 mm. 

 wide ; first glume narrow, usually present ; second glume and sterile lemma 

 attenuate-pointed, the tips often spreading, the glume about three-fourths the 

 length of the attenuate-pointed fruit. 



Cenchrus gracillimus, unlike our other species, begins blooming in the early 

 spring. Two collections from the west coast of Florida, Tracy's nos. 6744 and 

 7178, represent more robust plants than is typical, with mostly flat blades and 

 slightly larger burs. A specimen collected on Sanibel Island by A. S. Hitchcock 

 in 1900 and the two collections from Jamaica {Hitchcock 9S51 and Harris 

 12690) have burs very minutely puberulent. 



DISTRIBUTION. 



Sandy open ground and high pine land, Florida, southern Alabama, Cuba, 



and Jamaica. 



Florida : Suwanee County, Hitchcock 2290. Lake City, Hitchcock 2291. Sanford, 

 Hitchcock 790. Tavares, Hitchcock 810. Eustis, Curtiss 6615; Hitchcock 

 2288, 2289; Nash 188, 288, 1766. Grasmere, Combs <£- Baker 1031, 1079. 

 Zellwood, Baker 12. Brevard County, Fredholm 5826. Miami, Amer. Or. Nat. 

 Herb. 617; Chase 3847; Curtiss 5S20 ; Hitchcock 629, 662; Small & Carter 

 2854. Lakeland, Hitchcock 829. Tampa, Combs 1363. Hillsborough County, 

 Fredholm 6333, 6393. Dunedin, Tracy 6742. Cedar Key, Tracy 7178. 

 Johns Pass, Tracy 7181. Palma Sola, Tracy 6744. Sanibel Island, Hitch- 

 cock in 1900. 



Alabama: Mobile, Molir 64. 



Cuba : Isle of Pines, Britton, Britton & Wilson 14934. 



Jamaica: New Forest, Hitchcock 9851. Southern Manchester, Harris 12690. 



