104 CLASSIFICATION ACCORDING TO [CH. 



Mdica uniflora, also a wood-grass, has the spikelets two- 

 flowered, though the upper one may be a mere rudiment, and 

 much fewer, on a flexuoua nodding axis. The much rarer M. nutans 

 has two perfect flowers in the spikelet (see p. 105). 



(ii) Grasses of open situations, with numerous 



small pointed spikelets. Inner palea minute 



or absent. 



Agrostis. 



The genus most likely to give trouble here is Aira, which 

 though normally with two flowers in the spikelet, occasionally has 

 but one. As regards the common species of similar habit, &c., 

 Aira has bristle-like leaves and Agrostis flat ones. 



Again, Agrostis alba has no protruding awn, as in the spikelets 

 of Aira. For Aira cwspitosa and other details, see p. 117. 



* Awnless, or at most a short bristle not 



equalling the palea. Leaves flat and 



short. 



A. alba, L. 



An exceedingly variable plant. The variety A. stolonifera has a 

 less spreading panicle, and broader leaves with a long serrated 

 and pointed ligule : the variety A. imlgaris has a spreading loose 

 panicle, narrower leaves, and a short truncated ligule. There is, 

 however, much difficulty in distinguishing the intermediate forms 

 on mountain-pastures, &c. 



** Distinctly awned. Leaves narrower, the 

 lower ones inroUed and almost setaceous. 



A. canina, L. 



The rarer A. setacea, Curt, with subulate leaves and A. Spica- 

 venti, L. with long awns also come here. 



The lax spreading type of panicle characteristic of Aira and 

 Agrostis, &c., described above, occiu^ in species of Avena, Bromtis, 

 Briza, Poa and Catahrosa, but the basal silky hairs and twisted 

 awns {Avena), long sub-terminal bristle-awns (Bromus), habit 



