_Calamagrostis lanceolata_, Roth. Palea 3 mm. long, thin, two-toothed and with a short bristle at the apex. Other species of _Calamagrostis_ are awned. None occurs as an ordinary impurity in “seed.” _Arundo Phragmites_, L. Palea narrow and long, 10-11 mm., delicate, entire, tapering to an acuminate point, violet, three-nerved, smooth. Caryopsis about 2 mm. A pencil of long silky hairs on the rachilla. The long acuminate point is almost an awn. _Calamagrostis_ also has long basal hairs: both are useless grasses agriculturally. For _Glyceria_ see note, p. 146. _Avena_, _Aira_ and _Psamma_ are easily distinguished. ** Pencil of hairs short. † _Palea mucronate, 11-12 mm. long: caryopsis 4·5 mm._ _Psamma arenaria._ _Digraphis_ differs in the stout caryopsis, smaller size, double hair-tuft. _Arundo_ has a long pointed palea and long silky basal hairs and is larger. _Psamma arenaria_, Beauv. Palea 11·5 mm. ovate-lanceolate, papery, 4-5 nerved, as rolled round the fruit about 1·3 mm. diameter, yellow, and with a small tuft of stiff fine hairs at the base. Mere trace of awn, sub-terminal. Fruit 4-5 mm. long, obovate, pale-brown. A shore-grass, not often seen as “seed”: more valuable as a sand-binder than as fodder, though the young shoots are grazed. †† _Palea acuminate, and only about 4 mm. long: caryopsis 1·4 mm._ _Digraphis arundinacea._ A Fen-grass, but coarse and not in use except the young growth, and for thatching. _Digraphis arundinacea_, Trin. Paleæ ovate-lanceolate, nerveless and awnless, but silky with double basal hair-tuft, and polished at the base; smooth, hard and shining, and closely investing the caryopsis which has no groove. Dark grey in colour. The glumes are without awns or wings, and are left behind. The allied _Phalaris canariensis_ has wing-like keels to the glumes. _Triodia_ also comes into this group, with short basal hairs; but its broad ciliate palea, 6 mm. long, has a short mucronate point between two teeth (Fig. 40). (2) _Hairs at the base forming a fluffy “web.” Paleæ thin, 2-3 mm. long._ _Poa pratensis._ _P. trivialis._ _P. compressa._ _P. nemoralis._ The “seeds” of _Poa_ proper are nearly all small--not more than 3-4 mm., more or less lanceolate, with tough, keeled glumes, and when “webbed” tend to adhere together as if stuck with cobweb. The keeled glumes give them an angular appearance--triangular in section--and make them tend to lie on the side. Rachilla evident. Nerves of paleæ distinct. _Poa pratensis_, L. (Fig. 55). “Seed” 2-3 mm. long, brownish: caryopsis about 1-1·5 mm. Outer palea acute, indistinctly 3-5 nerved, edges and keel, silky; margins overlapping the hyaline inner palea. The “web” looks like hyphæ of a mould.