<;i: VMiM .1.. (GRASS family.) 547 



*- t- Lower palea entire, uwnless or (in No. 88) awii-pninted. 

 ++ Glumes unlike, the lower one linear, tho upper obovate. 



26. EATOXIA. Spikelets 1-5-tiowercd. Culms slender, tuftcil. 



++ +-* (Humes alike. Lower palea rounded on the baek, not keeled. 



27. MKI.ICA. Ppikelets 3-5-flowereii. Lower palea many-nerved. 



28. GLYCERIA. Spikelets 6 - many-flowered. Lower palea strongly 7-nerved. 



29. AKl MHNAIU.V. Spikelets looselj manj flowered. iiilms woody. 

 80. uxtlZOPYRUM. Spikelets dioecioos. Lower palea rigid. 



4+ ++ ++ Glumes alike. Lower palea keeled. 



31. POA. Palea? falling away together, the lower one 5-nerved, and with cobwebby hairs at 



the base. Spikelets 3-6-flowered. 



32. ERAGROSTIS. Lower palea falling before the upper one, 3-nervcd, not hairy. 



33. DACTYLIS. Lower palea awn-poiuted. Panicle contracled, composed of 1-sided clusters. 



* # Grain adherent to the upper palea, downy at the apex. 



34. FESTUCA. Lower palea entire, acute or awn-pointed. 



35. BROMUS. Lower palea 2-cleft, awned between the teeth. 



« » # Grain free, smooth. Lowest flowers of the spikelet imperfect. 



36. TTXIOLA. Spikelets broad and fiat, many -flowered. Palea? coriaceous. 



87. PHRAGMITES. Spikelets 3 - 6-flowered, silky bearded on the rachis. Palea? thin. 



Tribe V. HORDEACE.E. — Spikelets 2 - several-flowered, sessile, on opposite sides of 

 the jointed rachis, spiked. Glumes 1-2, rarely wanting. Palea? 2. 



38. ELYML'S. Spikelets 2 - 4 at each joint of the rachis. Glumes 2, placed side by side before 



the spikelets. 



39. GYMNOSTICHUM. Spikelets 2-3 at each joint of the rachis. Glumes none. 



40. LOLIUJI. Spikelet solitary at each joint of the rachis. Glume 1. 



Teibe VI. AVENACEjE. — Spikelets panicled, 2 - several-flowered, the terminal flow- 

 ers mostly imperfect. Rachis or base of the flowers often bearded. Lower palea with a 

 twisted, bent, or straight awn on the back, or below the apex. 



41. AIRA. Spikelets 2-flowered. Lower palea thin, rounded on the back, awned below the 



middle. 



42. TRISETUM. Spikelets 2 - several -flowered. Lower palea thin, compressed-keeled, bear- 



ing a bent awn below the 2-cleft apex. 



43. DANTIIOXIA. Spikelets 2 -several-flowered. Lower palea rigid, many -nerved, bearing 



a flattened and twisted awn at the 2-cleft apex. 



44. ARRHENATHERUM. Spikelets 2-flowered, tho lower flower staminate, and bearing a 



long bent awn below the middle. 



Tribe VII. FHALiARIDEJE. — Spikelets in spike-like panicles 3-flowercd, the upper 

 or middle flower perfect, the two lateral ones imperfect or mere rudiments. Glumes 2. 

 Palea? 2, indurated in fruit. 



45. AXTIIOXANTHUM. Lateral flowers neutral, eaclj of one awned palea. Perfect flower 



diandrous. 



46. PIIALAR1S. Lateral flowers rudimentary. Perfect flower triandrous. 



Tribe VIII. PAIVTCEjE. — Spikelets 2-flowered. Glumes 2, or the lower wanting. 

 Lower flower imperfect, either staminate or neutral, with the lower palea membrana- 

 ceous and similar to the upper glume, the upper one mostly wanting. Palea? of the 

 perfect flower coriaceous. Grain mostly grooved or flattened on the outside. Flowers 

 in spikes or panicles. 



» Lower glume and upper palea of the sterile flower wanting (the spikelet appearing like a 

 single flower, with 2 glumes and 2 paleae). 



47. PASPALDM. Spikelets alike, plano-convex, in 1-sided spikes. 



