Nardus stricta, L. (Moor Mat-grass). Roots very tough and stringy: ligule small, but thick and blunt. Leaves channelled: upper erect, lower horizontal. Sheath smooth. Moors and sandy heaths: useless (Figs. 2 and 26).
Aira flexuosa, L. (Wavy Hair-grass). Roots fibrous. Leaves short, filiform, terete, solid—the channel hardly discernible. Ligule short, obtuse. Heaths, &c. Of little use, even for sheep (Fig. [28]).
(β) Leaves bristle-like, but distinctly due to inrolling of edges.
Aira caryophyllea, L. (Silvery Hair-grass), is scabrid. A weed, with very slight foliage.
A. præcox, L. (Early Hair-grass). Greener and more glabrous. Habit more rigid.
A. canescens, L. (Grey Hair-grass). Glaucous or purplish; rare, on S.E. coasts.
(γ) Leaves narrow and more or less involute, and subulate upwards, but easily unrolled, and apt to become flatter as they age.
Avena pratensis, L. (Perennial Oat). Leaves rather thin, dry, harsh, ridgeless, with flanking lines and a keel[8]; glaucous, glabrous, but edges scabrous. Usually involute, but may open out. Ligule long ovate-acute. Dry pastures, especially on calcareous soil, and of little value.
Poa maritima, Huds. (Sea-grass). Leaves narrow, rather short, and U-shaped in section. Involute: ridgeless, with flanking lines, but no keel; soft and rather thick. Ligule rather long, obtuse and decurrent. Useless agriculturally.