POACEAE. 15 



from the involucre. — Hammocks, U. keys, L. keys, L. S. keys. — (Ber., Bah., 

 Cuba, Ant.) 



^"'Z. C. viridis Spreng. Similar to C. echinatus in habit, but brighter-green: 

 spikes mostly 3-10 cm. long: involucres crowded, with slender basal spines, the 

 bristles very slender. — Hammocks, U. keys. — (Bah., Cuba, Ant.) 



^'^4. C. incertus M. A. Curtis. Stems 3-6 dm. tall: blades 4-15 cm. long, 3-5 

 mm. wide: spikes 3-6 cm. long: involucres 8-20, containing 2 spikelets, pubes- 

 cent, ovoid, glabrous at the base, the spines about 3 mm. long, very broad at 

 the base, ciliate: spikelets 5 mm. long, exserted from the involucre.- — Open 

 sandy places, L. S. keys. 



16. STENOTAPKRUM Trin. Creeping, much-branched plants, with ter- 

 minal spikes or spike-like panicles. Spikelets 2- (rarely 1-) flowered, in 2 's-4 's 

 in short spikes. Scales 4. 



^ 1. S. secundatum (Walt.) Kuntze. Stems compressed: leaf -blades rounded at 

 the apex, usually less than 1 dm. long, 4-10 mm. wide: spikelets 3.5-5 mm. 

 long. — Coastal sand-dunes, U. S. keys, U. keys, L. keys. — [E. K.] — {Ber., Bah., 

 Cuba, Ant.)- — Shore-grass. 



17. HOMALOCENCHRUS Mieg. Grasses of wet situations. Spikelets 

 1-flowered.^ Scales 2, somewhat rigid, awnless, the first scale usually ciliate on 

 the keel, broader than the second. Stamens 1-6. 



1. H. monandrus (Sw.) Kuntze. Stems 4-6 dm. tall: leaf -blades erect, 4-15 

 cm. long, 2-5 mm. ^ide, roughish: panicle 7-13 cm. long: spikelets about 1 mm. 

 broad, smooth and glabrous. — Low hammocks and limesinks, U. keys, L. keys. — 

 {Cuba, Ant.) 



18. AE.ISTIDA L. Tufted plants with contracted or open panicles, which 

 are sometimes nearly racemose. Spikelets narrow. Scales 8, the outer 2 mem- 

 branous, the third scale narrow, rigid, strongly convolute, often with a promi- 

 nent callus at the base, the generally spreading awns glabrous to plumose. 



s^s'^l. A. purpurascens Poir. Stems 3-8 dm. tall: leaf -blades 5-20 cm. long: 

 panicle 1.5-3 dm. long: spikelets 9-12 mm. long, the flowering scale 6-8 mm. 

 long, the awns more or less spreading, especially the central one which is 1.5- 

 2.5 cm. long, the lateral awns from two-thirds as long to nearly equalling it. — 

 Pinelands, L. keys. — [E. K.] — {Bah.) — Poverty-grass. Wire-grass. 



19. MUHIiENBERGIA Schreb. Tufted or diffuse plants with terminal 

 contracted or open panicles. Spikelets small. Scales 3 (or rarely 4), the outer 

 2 persistent, membranous or hyaline, from minute to almost equalling the third 

 scale, keeled, acute, mucronate or rarely short-awned, the second occasionally 

 3-toothed, the third scale somewhat rigid, convolute at the apex, entire or 

 rarely 2-toothed, obtuse, acute, mucronate to long-awned, the awn very often 

 capillary, a fourth awned scale very rarely present. 



5^ 1. M. capillaris (Lam.) Trin. Stems wiry, 5-12 dm. tall: leaf -blades long and 

 narrow, often involute when dry, 1-3 mm. wide: panicle 1.5-4 dm. long, its 

 branches spreading or ascending: spikelets, exclusive of the awn, 3.5-4 mm. 

 long, lanceolate, acuminate, the empty scales usually one-half as long as the 

 spikelet or less, commonly bearing a short awn.- — Pinelands and coastal sand- 

 dunes, U. S. keys, L. keys. — [E. K.] — {Bah., Cuba.) 



20. SPOROBOLUS E. Br. Erect or diffuse plants with terminal panicles, 

 which are contracted or open and diffuse. Spikelets small. Scales 8, mem- 



