XXIX 



22. Arrhenatheram. — ' 



23. Hierochloe. 



28. Poa. 



29. Sclerochloa. 



30. Glyceria. 



31. Triodia. 



32. Briza. 



33. Dactylis. 



35. Festuca. 



36. Bromus, 



37. Avena. 



■Upper flower perfect, with a short awn ; lower 

 one stameniferous only, with a long twisted, 

 knee-bent awn. 



— Middle flower perfect, usually diandrous ; two 

 lateral ones stameniferous only, triandrous. 



— Spikelets awnless, ovate, mostly several-flowered. 

 Glumes and paleae more or less obtuse. Outer 

 palea compressed, three- or five-veined. 



— ^Flowers articulated with the rachis. Glumes 

 shorter than the flowers. Outer palea five- 

 veined, cylindrical below. 



— Flowers articulated with the rachis. Spikelets 

 linear or sub-cylindrical. Outer palea seven- 

 veined. 



— Glumes nearly equal in length to the flowers. 

 Outer palea three-toothed at the apex, rounded 

 on the back. 



— Spikelets much compressed, deltoid, or cordate. 

 Glumes shorter than the flowers. Outer 

 palea obtuse, boat-shaped. 



— Spikelets in dense, round-topped clusters at the 

 end of the branches of the panicle. Lower 

 palea with a short awn. 



— Glumes and paleae narrowing into a sharp point 

 or terminal awn. Styles terminating the 

 ovary. 



— Outer palea awned below the notched or bifid 

 apex. Styles from below the summit of the 

 ovary. 



— Paleae bifid, or with two points at the apex ; 

 lower one with a long knee-bent and twisted 

 dorsal awn. A. flavescens much resembles 

 Air a, but the spikelets are usually three- or 

 more-flowered. 



