rOACEAE. 13 



12. SYNTHERISMA \V:ilt. Diii'use plants with an inflorescence of spike- 

 like raeonit's. ^iiikolcts naiiow, acute, in 2 's or 3's 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 nienibraiious, the first small or wanting, the 

 fourth scale chartaceous, glal)rous and sliiiiiiig. at length indurated. — Crab- 

 grass or FiXGER-CiRASS. 



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

 times present as an inconspicuous rudiment. 



Second and third scales puliescent witli appressed glandular 

 tipped hairs : stems simple or sparingly branched at the 

 base; nodes ."> or fewer. 1. S.flUforme. 



Second and third scales glabrous. 2. H. Simpsonii. 



Rachis of the racemes with the lateral angles broadly winged, 

 thus making it appear flat: first scale usually present. 



Racemes very slender, the rachis usually less than 0.5 mm. 

 wide : spikelets 1/5 as wide as long, acuminate : fourth 

 scale greenish when mature. 3. .S. (Ihiildtinn. 



Racemes stouter, the rachis usually exceeding 0.7 mm. wide : 

 spikelets Vi as wide as long or more, acute : fourth scale 

 yellowish white when mature. 4. S. marcjinatmn. 



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.— F. K. {Bah., Cuba, Ant.) 



2. S. Simpsonii (Vasey) Nash. Stems S-12 dm. long: leaf-blades 7-30 cm. 

 long, 5 mm. wide or less, papillose-hirsute on both surfaces: axis of the 

 iuflorescenee 4-6 cm. long: racemes 6-8, 10-13 cm. long, erect or ascending, 

 usually scattered: spikelets a little exceeding 3 mm. long, about 1 mm. wide, 

 elliptic-lanceolate, acute, in pairs. — Pinelands. — (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. — F. K. (Bah., 

 Cuba, Ant.) 



4. S. marginatum (Link) Nash. Stems 8 dm. long or less: leaf -blades 2-8 

 cm. long, 5-10 mm. wide, glabrous or pubescent on both sides: axis of the 

 inflorescence 2 cm. long or le.ss: racemes 2-9, 2-12 cm. long, alternate, in pairs 

 or whorled: spikelets 3-3.5 mm. long, about 0.8 mm. wide, lanceolate, slenderly 

 acute, in pairs. — Everglades. — F. K. (Ber., Bah., Ant.) 



13. ECHINOCHLOA Beauv. Erect plants with the inflorescence of 

 several-many spike-like racemes. Spikelets crowded in small clusters or racemes 

 in 2 rows on all sides of the flat rachis. Scales 4, the 3 outer membranous, 

 spiny-hirsute or hispid, the first one often awn pointed, the second and third 

 awn-pointed or awned (rarely awnless), the latter bearing the longer awn, the 

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



1. E. Crus-galU (L.) Beauv. Stems 6-12 dm. tall: leaf-blades 1..5-6 dm. long, 

 6-25 mm. wide, glabrous: panicle of 5-15 erect or ascending branches, or the 

 lower branches spreading or reflexed and sometimes 6-8 cm. long: spikelets 

 ovate, densely crowded in 2-4 rows on one side of the rachis, the second and 

 third scales awned, the fourth scale abruptly pointed. — Everglades and pine- 

 lands, and cultivated grounds. Nat. from Eu. — (Ber.. Bah., Cuba, Ant.) — 

 Barxyard-grass, 



