162 CLASSIFICATION OF [CH. 
Agrostis canina, L., is somewhat larger than A. alba. 
Palea (only one present, sometimes minute) punctate, 
2mm., with a fine dorsal awn a little longer than the 
palea. Caryopsis 1°2mm. Rachilla obsolete. 
The awn is usually absent from 4d. a/ba and its varieties ; and 
when present is so small as to be almost negligible. 
A, canina is easily distinguished from Poa by the rachilla in the 
latter, and absence of awn. Aira has basal hairs, &c. 
Agrostis setacea, Curt., has the awn basal and just 
projecting beyond the pomted glumes, and the palea 
very minute, with a few silk} hairs below. 
Agrostis Spica-venti, L. (Fig. 49). 
Palea 2°4 mm. long, with infolded edges and punctate ; 
a minute rachilla at its base, and a slender awn, 8—9 mm. 
or more long, inserted below the bifid tip. Caryopsis 
15mm. A few silky hairs at the base of the palea. 
(6) Awn terminal or slightly sub-terminal, and 
straight, or at least not twisted or “kneed.” 
(1) Pale so closely adherent to the fruit that 
the terminal awn appears to come from 
the latter [Barley type]. The three florets 
generally coherent. 
*  Awn at least twice the length of the grain. 
Hordeum sylvaticum. 
H. murinum. 
Hordeum sylvaticum, Huds. 
Palea scabrid, ribbed above, awn at least twice as long 
as the very narrow grain. 
