GRAMINE.E 715 



awned hairy palet. 



8 Hierochloa Spikelets 3-flowered, the lateral ones staminate. 



Tribe v Agrostide.e Spikelets all hermaphrodite and fertile, 

 with 3 glumes, the first 2 empty. Rachella sometimes prolonged 

 behind the paleae into a naked or plumose bristle. 



* Flower sessile within the glumes. 



9 Coleantnus Spikelets in small umbellate clusters, all perfect. 



10 Sporobolus Spikelets in contracted or open panicles, all perfect. 



* * Flower raised within the glume on a short rounded or stalk- 

 like base. 



Glumes long-awned. 



11 Polypogon Glumes much longer than the flower. 



■*- *■ Glumes mostly awnle*s. 



12 Agrostis Lower glumes exceeding the very thin obtuse paleta : inflor- 

 escence spike-like to open paniculate. 



IS Gastrididm Inflorescence spike-like: glumes with a shining ventri- 

 cose base. 



14 Cinna Flower distinctly stipitate : flowering glume ahort-awned be- 

 low the tip. 



15 Muhlenbergia Flowers mostly bearded at base, early deciduous: 

 flowering glume awned from the apex. 



+- +- •*- Flowers with a more or less conspicuous tuft of hairs at 

 base, shorter than the glumes. 



16 Calamagrostis Spikelets 2-flowered and mostly with the rudiments 

 of a second flower present : palet awned from below the apex. 



Tribe iv Chlorides Spikelets one, to several- flowered, in 

 simple one-sided spikes, upon a jointless rachis. 



* Spikelets one-flowered. 



17 Spartina Spikelets much flattened laterally, in 2 rows upon one side 

 of a 3-angled rachis: spikes racemed. 



18 Beckmannia Spikes panicled : spikelets 2-flowered, or by abortion 

 1-flowered, upon one side of a flattened rachis. 



* * Spikelets 2-flowered or more, one flower perfect with one or 

 more imperfect or neutral ones above it. 



19 Bouteloua Flowering glumes 3-cleft and 3-awned at the apex : im- 

 perfect flowers often reduced to these awns. 



20 Elkusine Spikes digitate at the summit of the stem: spikelets sev- 

 eral-flowered. 



Tribe v Stipace^e Spikelets strictly one-flowered. Flowers 

 with a sharp-pointed callus at base, deciduous. Flowering glume 

 wrapped around the flower and palet, coriaceous and indurated 

 in fruit and terminated by a simple or triple awn. 



21 Stipa Awn simple, long, twisted below, not caducous. 



22 Oryzopsis Awn simple, caducous : flower clothed with long silky hairs. 



