538 GK.VMINF.JE. (OR ASS FAMILY.) 



87. BROMUS. Lower palea convex or keeled on the back, mostly awncd or bristle-bearing be- 



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

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



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



palea Flowers strongly compressed keeled, crowded, coriaceous. 



89 PHKAGMITES Spikelets strongly silky-bearded on the rhachis ; loosely-flowered, the low- 

 est flower staminate or neutral. Palt'te membrauaceous. 



* * * Culms woody, suffruticose or arborescent. 



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



Subtribe 5. HORDEINE.E Spikelets 1 - several flowered, sessile on opposite sides of a zig/Ag 

 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, 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. 



43. TRITiCU.M. Glumes 2, transverse (right and left) ; spikelets placed flatwise on the rhachis 



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

 -i- 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. 



-i- -i- Glumes none or 1 - 2 awn-like rudiments 



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



Subtribe 6. AVEXE^. 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. 



* Flowers all perfect, or the uppermost merely rudimentary. 

 t- 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. 



H- H- Lower palea cleft at the apex into 2 acute or sharp-pointed teeth 

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



48. DANTHONIA. Lower palea rounded on the back ; the awn flat, spirally twisted. 



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



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



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



* * One of the flowers staminate only. 

 61. ARRIIENATHERUM. Lower flower staminate ; the perfect one commonly awnleas ; the 



uppermost a rudiment : otherwise as No. 50. 

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



none. 



TRIBE II. PHAL,ARIDE^E, 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. AMJIOXA.NTHE^. Lateral flowers mostly awned, staminate or neutral, of 1 or 2 

 paleac ; the perfect one awnless and diandrous. Upper palea l-nerved. 



63. HIEROCHLOA Lateral flowers staminate and triandrous, of 2 paleae. 



64. ANTHOXANT1IUM 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 awnless and triandrous. 



66. PIIAI.AI'JS (I'uiiHs b.ut-shap.-d. keeled, enelosin;: the coriweoua fertile Hover, vrhich if 

 KOinesvhiU fl.ittened laterally. 



