186 88. GE AMINES. 



racemes or panicles. Each spikelet is usually composed of 2 (or 1, 

 rarely none) outer imbricated empty glumes; these contain 1 2 

 or more perfect florets; sometimes imperfect, often rudimentary 

 or neuter ones are produced. Each floret is composed of 2 chaffy 

 glumellas, enclosing the essential organs (usually 3 stamens, 1 

 style, and 2 stigmas); the lower or outer one with a central 

 midrib or keel; the inner (supposed to be 2-united) having 2 

 lateral ones. Ovary 1 -celled, with 2 minute scales (sometimes 

 1 or none) at the base, called lodicules. Fruit 1-seeded (a caryopsis) , 

 closely covered by the pericarp, sometimes the glumellas adhere 

 to the seed. 



KEY TO THE GENERA OF GRAMINE^. 



A. Style and stigma 1. Glumes none. Gen. 1. 



B. Styles or stigmas 2. Stamens 3 (rarely 1). Gen. 2 30. 



1. Spikelets with 1 perfect floret. Gen. 210. 



* Inflorescence dense, panicle close and spike-like. Gen. 2 6. 



** Inflorescence a loose branched panicle. Gen. 7 10. 



2. Spikelets with 2 perfect florets. Gen. 1118. 



t Glumellas without awns. Gen. 11 13. 



ft Glumellas awned. Gen. 1418. 



3. Spikelets with 34 perfect florets. Gen. 1926. 



4. Spikelets with numerous florets, mostly sessile, upon opposite 



sides of the rachis. Gen. 27 30. 



GENERA. 

 A. Style and stigma 1. Glumes none. 



1. NARDUS. Spikelets sessile, unilateral, with 1 -floret. Spike 



simple. 

 B. Styles or stigmas 2. Stamens 3 (rarely 1). Gen. 230. 



1. Spikelets with 1 perfect floret. 

 * Inflorescence dense, panicle close and spike -like. 



2. ALOPECURTJS. Glumes without awns. Glumella one, with a 



long dorsal awn from below the centre. 



3. PHLEUM. Glumes with a short terminal awn. Glumellas 



membranous, awnless. 



4. ANTHOXANTHUM. Glumes very unequal. Glumellas equal, 



awned at the back. Stamens 2. 



5. PSAMMA. Glumes and glumellas awnless, hairy at the base. 



6. PHALARIS. Glumes awnless, keel expanded into a wing. 



Glumellas awnless. 



** Inflorescence a loose branched panicle. 



7. DIGRAPHIS. Glumes and glumellas awnless, the latter with 



two hairy scales at the base. 



