10 POACEAE. 



brous: racemes ascending, 2-5 cm. long: spikelets singly disposed, the third 

 scale strongly pubescent at the apex. Hammocks and lime-sinks, L. keys. 

 (Ber., Bah., Cuba, Ant.) 



8. P. vaginatum Sw. Stems 2-6 dm. tall: leaf -sheaths usually crowded and 

 overlapping, at least at the base and on the innovations, glabrous: blades 

 folded, or involute when dry, 1.5 dm. long or less, 2-4 mm. wide, glabrous or 

 nearly so: racemes usually in pairs, erect or ascending, 3-7 cm. long: spikelets 

 singly disposed, the 2 outer scales thin, the third scale glabrous at the apex. 

 Hammocks, L. keys. (Ber., Bah., Cuba, Ant.) 



6. ERIOCHLOA H.B.K. Erect plants with an inflorescence of spike-like 

 one-sided racemes which are racemosely arranged. Spikelets imbricated, 

 arranged in 2 rows on a flat rachis, acute or acuminate. Scales 3, the 2 outer 

 membranous, appressed-pubescent, empty, the third scale glabrous and shining, 

 shorter, at length indurated, awn-pointed or short-awned at the apex. 



1. E. Michauxii (E. & S.) A. Hitchc. Stems single, 7-15 dm. tall: leaf- 

 sheaths glabrous or softly pubescent; blades 1-4.5 dm. long, 4-15 mm. wide: 

 inflorescence 1.54 dm. long: racemes 8-20, 3-15 cm. long: spikelets 12-40, 

 5-5.5 mm. long, ovate, the third scale about 3.5 mm. long, rather finely trans- 

 verse-rugose. Pinelands and edges of hammocks, L. keys. [E. K.] 



7. SYNTHERISMA Walt. Diffuse plants with an inflorescence of spike- 

 like racemes. Spikelets narrow, acute, in 2 's or 3 'a on one side of the flat and 

 winged or triangular rachis, one of the spikelets usually longer-pedicelled than 

 the rest. Scales 3 or 4, the 3 outer membranous, the first small or wanting, the 

 fourth scale chartaceous, glabrous and shining, at length indurated. CRAB- 

 GRASS or FINGER-GRASS. 



Rachis of the racemes with the angles naked, not winged : first scale wanting or some- 

 times present as an inconspicuous rudiment. 1. S. flliforme. 

 Rachis of the racemes with the lateral angles broadly winged, 



thus making It appear flat : first scale usually present. 

 Pedicels terete or obscurely angled, sparingly, if at all, his- 



pidulous. 2. 8. serotinum. 



Pedicels sharply 3-angled, the angles strongly hispidulous. 

 Racemes very slender, the rachis usually less than 0.5 

 mm. wide : spikelets ^ as wide as long, acuminate : 

 fourth scale greenish when mature. 3. 8. digitatum. 



Racemes stouter, the rachis usually exceeding 0.7 mm. 

 wide : spikelets \4 as wide as long or more, acute : 

 fourth scale yellowish-white when mature. 4. S. marginatiitn. 



1. S. filiforme (L.) Nash. Stem 1.5-7 dm. tall: leaf -sheaths papillose-hirsute; 

 blades 3-20 cm. long, 1-4 mm. wide: axis of the inflorescence 1-3 cm. long: 

 racemes 2-5: spikelets 0.75 mm. wide, elliptic, acute, in pairs, the fourth scale 

 exceeding the third, deep chestnut-brown when mature. Hammocks and pine- 

 lands, U. keys, L. keys. [E. K.](Bah., Cuba, Ant.) 



2. S. serotinum Walt. Stems 2-5 dm. tall: leaf-blades 1.5-10 cm. long, 

 3-10 mm. wide, ascending, pubescent on both surfaces: axis of the panicle 1-2 

 cm. long: racemes 2-6, 2.5-10 cm. long, ascending, usually alternate: spikelets 

 about 1.5 mm. long, about 0.6 mm. wide, elliptic, acute, usually in pairs. 

 Hammocks, U. keys. (Cuba.) 



3. S. digitatum (Sw.) A. Hitchc. Stems tufted, 4-10 dm. tall or less: leaf- 

 blades 2-12 cm. long, 2-7 mm. wide, papillose-hirsute on both surfaces: axis 

 of the inflorescence 4 cm. long or less: racemes 4-13, 4-13 cm. long, usually in 

 a whorl at the base and the remainder alternate or approximately in pairs; 

 spikelets about 2.5 mm. long, about 0.5 mm. wide, lanceolate, acuminate, in 

 pairs, occasionally with a delicate basal bristle. Hammocks, U. keys, L. keys. 

 [E. ~K.](Bah., Cuba, Ant.) 



