evil. GRAMINE^* 525 



§§ Spihelets of one perfect and I — 2 triandrous florets, 



19. HoLCUS. Florets 2, triandrous ; lower perfect, upper barren, awned. 



20. ARRHENATHERaM. Florets 2, triandrous; upper perfect, with a 



short bristle at the point ; lower barren, with a long twisted geni- 

 culate awn above the base of the outer glumella. 



21. HiEROCHLOE. Florets 3, awnless; central one perfect, diandrous; 



barren ones lateral, triandrous. 



JJ Panicle spiked, 



22. KoELERiA. Panicle rounded, Spikelets distichous, without a brac- 



tea at the base. Glumes unequal ; upper one with several nerves. 

 Glumellas membranaceous; outer one keeled, entire, pointed. 



23. Seslekia. Panicle rounded, Spikelets laterally compressed, with- 



out a bractea at the base. Glumes about as long or longer than 

 the florets, nearly equal, 1-nerved. Glumellas membranaceous; 

 outer one keeled, jagged, with a short terminal bristle. 

 30. Cynosurus. Panicle unilateral. Spikelets distichous, with a pecti- 

 nate bractea at its base. Glumes much shorter than the florets, 

 equal, 1-nerved. Glumellas membranaceous; outer one linear- 

 lanceolate, mucronate or awned at the end. 



If Spikelets broader than thick, dorsaUy (not laterally') compressed. Perfect 

 floret 1, its glumellas hardening on the caryopsis ; yieuter as large as 

 the perfect one, of one glumella, 



9. Milium. Panicle lax, diffuse. Glume 1, the lower one wanting. 

 Neuter glumella herbaceous, and resembling the glume, 



J 



f f f Spikelets flat in front, gibbous or rounded 07i the back {not laterally 



compressed). Perfect floret 1, its glumellas hardening on the cary- 

 opsis ; barren or neuter as large as the perfect one, of 1 — 2 glumellas, 



24- Panicum, Panicle in a racemose somewhat unilateral compound 



spike, Spikelets without bristles at the base, awned, arranged on 

 one side of a flattened partial rachis. Glumes 2 ; lower one the 

 smaller. 



44, DiGiTARiA, Spikelets without bristles at the base, awnless, arranged 



on one side of a spreading partial rachis, and forming a digitate 

 or shortly racemose compound spike. Glumes 2; lower one the 

 smaller and sometimes obsolete, 



25, Setaria. Panicle in a compound cylindrical dense spike. Spike- 

 lets 1 — 8 together, surrounded by an involucre of bristles and sepa- 

 rating from it, 



*** Spikelets with 3 or more perfect florets, laterally compressed. Glumes 2. 



f Outer glumellas with a dorsal awn from or below the middle. 



16, AiRA. Panicle lax, Spikelets laterally compressed, with 3 perfect 



florets. Glumes about as long as the florets, membranous. Glu- 

 mellas 2; outer ones hairy at the base, 1-nerved, jagged at the 

 end, with a slender dorsal awn from belovr the middle. 



33. AvENNA. Panicle lax, Spikelets laterally compressed, with 3 or 



more perfect florets. Glumes membranaceous, about as long as 

 the spikelet. Glumellas lanceolate, hairy at the base, herbaceous 



