552 COMMON GRASSES OF THE FARM 



SUMMARY OF GENERIC CHARACTERS OF THE COMMON FARM GRASS. S. 



A. Inflorescence a panicle : in some cases the stalks (pedicels) of the spike- 

 lels are very short, and the panicle is spike-like. 



1 . Spikelets with only one perfect flower. 



a. Empty glumes four ; panicle spike-like. Anthoxanthuni. 



b. Empty glumes two. 



(i) Panicle spike-like (Fig. 172). (Seep. 531.) Alopecurus. 



(See p. 532.) Phleum. 



(Seep. 533.) Ammophila. 



(ii) Panicle spreading (Fig. 174). Agrostis. 



2. Spikelets with two or more flowers. 



a. Empty glumes equal to or longer than the flowering glume, often 



hiding from view the rest of the spikelet. 

 The flowering glume generally awned ; awn dorsal, twisted and bent 



{B, Fig. 176), except in Aira and Deschampsia. 

 (i) Spikelets with two flowers ; upper one male, 



lower one bisexual. Hokus. 



(ii) Spikelets with two flowers ; lower one male, 



upper one bisexual. Arrhenatherum. 



(iii) Spikelets with two or more bisexual flowers. 



(See p. S37.) Deschampsid. 

 (Seep. 538.) Trisetuin. 

 (See p. 539.) Avena. 



b. Empty glumes shorter than the flowering glumes, the rest of the 



spikelet generally visible {B, Fig. 182). 

 When the flowering glume is awned, the awn is terminal and 



generally straight (Fig. 184). 

 (i) Panicle spike-like (Fig. 179). Cyncsurus. 



(ii) Panicleof dense clusters of spikelets (Fig. 180). Dactylis. 

 (iii) Panicle spreading (Fig. 181). 



* Flowering glume compressed with a keel 



along its whole length ; no awns. Poa. 



** Flowering glumes rounded on the back, and 

 upper part only keeled ; sometimes awned. 



(See p. S43. ) Festuca. 

 (Seep. 545.) Bromus. 



B. Inflorescence a spike (Fig. 186) : the spikelets sessile, arranged direclly 

 in notches on the single main axis. 



1. Spikelets one-flowered. 



a. One spikelet at each notch (Fig. 185). Nardus. 



b. Three spikelets at each notch (Fig. 159). Hordeum. 



2. Spikelets with two or more flowers. 

 a. One spikelet at each notch. 



