POACEAE. 11 



cm. long, the rachis slender, densely clothed with silky hairs longer than them- 

 selves; sessile spikelets linear-lanceolate, 5 mm. long, bearing a slender straight 

 awn 6-10 mm. long. Pinelands. 



5. A. Elliott! Chapm. Stems tufted, 5-8 dm. tall: racemes 3-4 cm. long, the 

 longer one at each node exserted, the others concealed in the spathes: sessile 

 spikelet 4.5-5 mm. long, the awn geniculate, 1.5-2.5 cm. long, usually spiral at 

 the base, the column exserted. Everglades. 



6. CHEYSOPOGON Trin. Erect plants with terminal panicles, whose 

 branches usually bear clusters of 3 spikelets, or very rarely more, at the end, 

 one spikelet sessile and perfect, the other 2 staminate or sterile and pedicellate. 

 Sessile spikelet usually somewhat laterally compressed, of 4 scales, usually 

 awned. Pedicellate spikelet dorsally compressed, awnless or awned. 



1. C. pauciflorus (Chapm.) Benth. Annual: stems 6-12 dm. tall: panicle 2-3 

 dm. long: sessile spikelet about 15 mm. long, including the 6-7 mm. long and 

 densely pubescent callus, cylindric or slightly laterally compressed, emitting a 

 flexuous more or less contorted usually geniculate awn 14-16 cm. long. 

 Pinelands. (Cuba.) 



7. HETEROPOGON Pers. Erect plants with terminal solitary dense 

 racemes. Spikelets 1-flowered, one sessile and fertile, the other pedicellate and 

 staminate or empty. Scales of the sessile spikelet 4, the fourth scale, enclosing 

 a pistillate flower, small and hyaline and bearing a long rigid contorted and 

 geniculate awn. Pedicellate spikelet awnless. 



1. H. contortus (L.) Beauv. Perennial: stems 2-8 dm. tall, rather sparingly 

 branched above: racemes 4-6 cm. long: sessile spikelet 5-6 mm. long, the awn 

 4.5-8 cm. long: pedicellate spikelet about 1 cm. long, sterile or staminate, the 

 first scale acute. Pinelands. (Cuba.) 



8. COELORACHIS Brongn. Erect or diffuse plants with articulate racemes. 

 Scales of the sessile spikelet 4, the outermost thick and coriaceous, sometimes 

 more or less rugose or pitted, concealing, together with the pedicel of the 

 other spikelet, the remaining scales and the excavation in the rachis. 



1. C. rugosa (Nutt.) Nash. Stems 7-12 dm. tall, stout: racemes 5-8 cm. 

 long, the rachis-internodes usually contracted at the base: sessile spikelet 3.5- 

 4.5 mm. long. Everglades. 



9. HACKELOCHLOA Kuntze. Erect plants with branched stems. 

 Spikelets in excavations at the rachis joints, Scales of the sessile spikelet 4, 

 awnless, the outermost pitted, covering the excavation in the rachis. 



1. H. granularis (L.) Kuntze. Stems 2-10 dm. tall, finally much-branched: 

 leaf -sheaths papillose-hirsute: racemes 1-2 cm. long: sessile spikelet about 1 

 mm. in diameter. Pinelands and everglades. Nat. from the tropics. (Cuba.) 



10. PASPALUM L. Erect or diffuse plants with an inflorescence composed 

 of one or more unilateral racemes, arranged singly, in pairs, or in panicles. 

 Spikelets 1-flowered, obtuse, or rarely short-acuminate, nearly sessile or short- 

 pedicelled, singly or in pairs, on one side of a narrow and usually winged 

 rachis. Scales 3 or rarely 4. 



Stem with 1-several raceme-bearing naked branches from the uppermost sheath. 



Leaf-blades conspicuously ciliate. 1. P. ciliatifolium. 



Leaf-blades not ciliate. 2. P. rigidifolium. 



Stem simple, without raceme-bearing branches from the upper 

 sheath. 



