538 GR AMINES. (grass FAMILY.) 



37. BROMTJS, Lower palea convex or keeled on the back, mostly awned or bristle-bearing be* 



low the 2-cleft tip, 5 - 9-nerved. Styles subterminal. 

 * * Culms herbaceous, often tall and reed-like. Lowest flower sterile. Grain free. 



38. UNIOLA. Spikelets very flat ; the one or more lowest flowers neutral, of a single empty 



palea. Flowers strongly compressed keeled, crowded, coriaceous. 

 89. PHRAGMITES Spikelets strongly silky-bearded on the rhachis, loosely-flowered, the low- 

 est flower staminate or neutral. Paleoe membTanaceous. 



* * * Culms woody, suffruticose or arborescent. 



40. ARUNDINARIA. Spikelets flattened, loosely 5 - 14-flowereii : the jointed rhachis naked. 



Subtribe 5. Hordeinb^ Spikelets 1 - several-flowered, sessile on opposite sides of a zigzag 

 jointed rhachis (which is excavated or channelled on one side of each joint), forming a 

 spike. Glumes sometimes abortive or wanting. — Otherwise as in the preceding subtribe. 

 * Spikelets single at each joint of the rhachis, l-flowered. Spikes often several. 



41. LEPTURUS. Spikelets almost immersed in the excavations of the slender rhacbis. 



* * Spikelets single at each joint of the rhachis, several-flowered. Spike solitary. 



42. L0LII7M. Glume 1, external : spikelets placed edgewise on the rhachis. 



43. TRITICUM. Glumes 2, transverse (right and left) ; spikelets placed flatwise on the rhachiB. 



* * * Spikelets 2 or more at each joint of the rhachis. Spike solitary, 

 •t- Glumes anterior, forming a sort of involucre for the cluster of spikelets. 



44. HORDEUM. Spikelets l-flowered, 3 at each joint, but the two lateral usually sterile. 



45. ELYMUS Spikelets 1 - several-flowered, all perfect and similar. 



•1- -f- Glumes none or 1 - 2 awn-like rudiments 



46. QYMNOSTICHUM. Spikelets few-flowered, somewhat pedicelled, 1 - 3 at each joint. 



Subtribe 6. AvEWsiE. Spikelets 2 - several-flowered, panicled ; the rhachis or base of the 

 flowers often villous-bearded. Glumes mostly equalling or exceeding the flowers. Low- 

 er palea bearing a twisted, bent, or straight awn on its back or below its apex (in No. 48 

 between the teeth) ; the upper 2-nerved. Stamens 3. 



* Elowers all perfect, or the uppermost merely rudimentary. 

 ■I- Lower paloa truncate or obtuse, its summit mostly denticulate or eroded. 



47. AIRA. Awn on the back or near the base of the palea, bent or straight. 



■t- ■•- Lower palea cleft at the apex into 2 acute or sharp-pointed teeth 

 ++ Awn borne between the sharp or awn~pointed teeth ; proceeding from 3 middle nerves. 

 48 DANTIIONIA, Lower palea rounded on the back ; the awn flat, spirally tmsted. 

 ■H- -H- Awn below the apex or dorsal, proceeding from the midnerve only. 



49. TRTSETUM. Lower palea compressed-keeled. Awn mostly bent or flexuoua. 



50. AVBNA. Lower palea rounded on the back. Awn mostly twisted or bent. 



* * One of the flowers staminate only. 

 61. AllRIIENATHERUM. Lower flower staminate; the perfect one commonly awnlcss ; the 



uppermost a rudiment t otherwise as No. 50. 

 52 HOLCUS. Lower flower perfect, awnless ; the upper staminate and awned : rudiment 



none. 



Tribe II. PHAIjARIDE.*], Trin. (not of Kunth). Spikelets 3-flowered ; the upper- 

 most or middle (terminal) flower perfect; the two lower (one on each side) imperfect, 

 either staminate, neutral, or reduced to an inconspicuous rudimeut. 

 Subtribe 1. ANTHOx-iNTHE.^, Lateral flowers mostly awned, staminate or neutral, of 1 or 2 

 palese ; the perfect one awnless and diandrous. Upper palea 1-nerved. 

 63. inEUOCHLOA Lateral flowers staminate and triandrous, of 2 paleie. 

 54. ANTHOXANTHUM. Lateral flowers neutral, each of a single awned palea. 



Subtribe 2. PHALARiDEiE Proper Lateral flowers reduced to a small neutral radiment on 

 each side of the fertile one ; which is awnless and triandrous. 

 65. PHALARIS Glumes boat-shaped, keeled, enclcsing the coriaceous fertile flover, which la 

 somewhat flattened laterally. 



