538 GRAMINE^E. (GRASS FAMILY.) 



37. BROMUS. Lower palea convex or keel?" on the back, mostly awned or brittle-bearing l:e 



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

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



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



palea Flowers strongly compressed keeled, crowded, coriaceous. 



89. PHRAGMJTE3. Spikelets strongly silky-bearded on the rhachis, loosely-flowered, the low- 



est flower staminate or neutral. Paleae membranaceous. 



* * * Culms woody, suffruticose or arborescent. 



40. ARUNDJNARIA. Spikelets flattened, loosely 6- 14-flowered : the jointed rhachis naked. 



Bubtribe 5. HORDEINE.S. 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 

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

 * Spikelets single at each joint of the rhachis, 1-flowered. Spikes often several. 



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



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



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



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



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

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



44. HORDEUM. Spikelets 1-flowered, 3 at each joint, but the two lateral usually sterile. 



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



- t- Glumes none or 1 - 2 awn-like rudiments. 

 4f,. GYMNOSTICIIUM. Spikelets few-flowered, somewhat pedicelled, 1 - 3 at each joint. 



Suotribe 6. AVEXES:. Spikelets 2 - several-flowered, panicled ; the rhachis or base of tbo 

 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 (hi J'o. 18 

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



* Flowers all perfect, or the uppermost merely rudimentary. 

 - Lower palea 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. 



i- - 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 nerve*. 

 48. DANTIIONIA. Lower ^alea rounded on the back ; the a\vn flat, spirally twisted, 

 w- ++ Awn below the apex or dorsal, proceeding from the midncrve only. 



43. TRISETUM. Lower palea compressed-keeled. Awn mostly bent or flexuous. 

 60. AVENA. Lower palea rounded on the back. Awn mostly twisted or bent. 



* * One of the flowers staminate only. 

 f>1. AHKIIENATHERTJM. Lower flower staminate ; the perfect one commonly awnless ; tha 



uppermost a rudiment : otherwise as No. 50. 

 62. IIOLCUS. Lower flower perfect, awnless ; the upper staminate and awned : rudiment 



none 



TRIBE II. PHAL-ARIDEjE, 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 rudiment. 

 Subtribe 1. ANTHOXA.NTIIE*. Lateral flowers mostly awned, staminate or neutral, of 1 or 2 



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

 5". II1EROCIILOA Lateral flowers staminate and triandrous, of 2 paleze. 

 64. ANTHOXANTHCM. Lateral flowers neutral, each of a single awned palea. 



Subtribe 2. PHALARIDE* Proper. Lateral flowers reduced to a small neutral rudiment on 



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



56. PHALARIS. Glumes boat-shaped, keeled, enclosing the coriaceous fertils flower, which if 

 somewhat flattened laterally. 



