The palea has a few hairs on its mid-rib below. Caryopsis about 1 mm. long. This grass is somewhat rare in England. The jointed basal awn, with a minute hair-tuft above the middle, is unique, and readily distinguishes it when mixed with _Agrostis_. ⊙⊙ _Awn not bearded or thickened._ ≡ _Palea bifid at apex._ _Aira caryophyllea._ _A. præcox._ _Aira caryophyllea_, L. “Seed” 1·4-1·6 mm., comma-shaped and dark-brown. Palea acute, nerveless, inrolled at edges and with a dorsal, kneed, very fine, dark twisted awn twice as long as the palea: the latter with two-toothed apex and a basal hair-tuft. A common impurity in commercial seed. _Aira præcox_, L. is very similar, and cannot be distinguished with certainty by the “seed,” but has a shorter awn and no basal hairs. Apex of palea two-toothed. ≡≡ _Palea jagged or toothed, but not bifid._ _Aira flexuosa._ _A. cæspitosa._ _Aira flexuosa_, L. (Fig. 70). Palea 5 mm. long, four-toothed at the apex, and caryopsis 2·6 mm. The fine basal awn waved or kneed, about twice as long as the palea. Fruit with a groove. Rachilla hairy. Whole “seed” browner than _Avena flavescens_ (see p. 158). [Illustration: Fig. 70. _Aira flexuosa. a_, “seed,” nat. size; _c_ and _d_, the same, × about 7; _b_, portion of fruiting panicle, showing the flexuous rachis; _e_, the caryopsis, nat. size; _f_, ditto, × about 7. Note the basal hairs and twisted awn. Nobbe. Cf. Fig. 44.] An almost worthless grass, on sandy soils, but important as an impurity in _Avena flavescens_ (see note, p. 158). _Aira cæspitosa_, L. (Fig. 44). The palea, about 2·5 mm. long, toothed above, has a fine straight hair-like basal awn not longer than itself. Caryopsis 1·3 mm., grooved. Rachilla distinctly hairy. Easily distinguished when mixed with _Poa nemoralis_, &c.--e.g. by the awn, hairs on rachilla, &c. It requires scrutiny in regard to _Agrostis_, which also has no awn or basal hairs. ** No basal tuft, or merely a few short microscopic hairs below. Paleæ not bifid above. _Agrostis canina._ _A. Spica-venti._ _A. setacea._ _Agrostis canina_, L., is somewhat larger than _A. alba_. Palea (only one present, sometimes minute) punctate, 2 mm., with a fine dorsal awn a little longer than the palea. Caryopsis 1·2 mm. Rachilla obsolete. The awn is usually absent from _A. alba_ 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 pointed glumes, and the palea very minute, with a few silky hairs below. _Agrostis Spica-venti_, L. (Fig. 49).