Gramineae. 



i6i 



619 Outer glumes equal, 623 



619 Upper glume smaller than the lower, . 



620 Florets with an awn, 624 



620 Florets without an awn, 625 

 62 1 Panicles dense resembling an ovate spike, . 

 621 Panicle ovoid loose spike-like, .... 

 621 Panicle pyramidal spreading, 626 



622 Spikelets 2 — 4 times as long as broad, . 



622 Spikelets many times longer than broad, 

 623 Flowering glumes with few hairs, 

 623 Flowering glumes with many silky hairs, 



624 Aquatic plants, ..... 



624 Land plants, 627 

 625 Spikelets in fascicles, the lower ones with an in- 

 volucre at the base, 629 

 625 Involucre absent, 630 



626 Perfect floret with a short awn, 



626 Perfect floret unawned, 

 627 Empty glumes smaller than the flowering glumes, 

 627 Empty glumes larger than the flowering glumes, 



628 Fruit adherent to the palea, 633 



628 Fruit not adherent to the palea, 634 

 629 Panicle ovate, ....... 



629 Panicle linear one-sided, ..... 



630 Fruit adherent to the palea, . 



630 Fruit not adherent to the palea, 632 

 Spikelets 2-flowered, flowering glumes small 



toothed or bifid awned at the back, . 

 Spikelets 3-flowered, flowering glumes large ter- 

 minating in bristly points with a long twisted 



. Agrostis VIII. 



. Ammophila IX. 

 . Phalaris X 



63 J 

 63^ 



632 Empty glumes much longer than the 



flowering glumes, .... 



632 Empty glumes shorter than the flowering 



glumes, 635 



633 Flowering glumes 3 — 5 nerved with a terminal awn, 



633 Flowering glumes 5 — 9 nerved, awned below the 



apex, 



Triticum XI. 



Brachypodium XII. 



Milium XIII. 



Calamagrostis XIV. 



Phragmites XXIV. 



Arrhenatherum XV. 

 Holcus XVI. 

 628 

 631 



Sesleria XXI. 



Cynosurus XXII. 



Briza XXIII. 



Aira XVIII. 



Avena XIX. 

 . Triodia XXV. 



. Festuca XVII. 

 . Bromus XX. 



