Aira flexuosa. Upper surface a depression, with one ridge flanked by two grooves at its base, the depression extending about one-fifth through the whole thickness of the nearly solid leaf. Vascular bundles about 3-5, isolated, sheathed. Sclerenchyma band extending all round the lower surface just inside the thick cuticle. Stomata very few, flanking the ridge; motor-cells in the furrows, poorly developed (Fig. [28]).
⊙⊙ Section elliptical or angular-ovate; sclerenchyma not always in a continuous band below.
Festuca ovina. Upper surface a deep fold, with three ridges and 2-4 grooves at its base. Vascular bundles several, with girders. Motor-cells in four series, in the grooves. The lower girders may not fuse laterally into a continuous band of sclerenchyma below (Fig. [18]).
The folded lower leaves of F. rubra and F. heterophylla come here also. For the flatter leaves of F. duriuscula see p. [78] and compare Fig. [27].
The epidermal cells in this series have sinuous thickened walls, and here and there small tooth-like hairs.
Nardus also comes here (see Fig. [26]).
(2) There are stomata below, but fewer than on the upper surface. Motor-cells usually conspicuous between the ridges.
✲ Stronger bundles with girders of sclerenchyma joining them to the epidermis, at least below.
⊙ Hairs sparse or none.
Cynosurus cristatus. Mid-rib obsolete, except the strong vascular bundle. Ridges low and rounded, with 2-4 flanking stomata, and well developed motor-cells in furrows. Secondary vascular bundles with strong girders below, the smaller bundles sheathed only and isolated. Each ridge with slight sclerenchyma above. A few stiff short hairs above, and the leaves are convolute. Ridges about twice the height of the leaf-thickness between (Fig. [16]).
Agropyrum repens. Mid-rib and margin with strong sclerenchyma-groups: ridges unequal, low and rounded and each vascular bundle girdered. A few pointed hairs above, and motor-cells in all the grooves. A slight keel, stomata on both surfaces.
Agropyrum caninum. All the bundles have girders. Slight keel. Marginal sclerenchyma. Few, very short, hard, hooked asperities above and below. Ridges low, and motor-cells poorly developed between. Few stomata on lower surface. Very like A. repens, but the principal ridges are more prominent below and those nearer the mid-rib have asperities.
A. junceum resembles Psamma, but the ridges are much lower, and there are a few stomata on the under surface (Fig. [24]).
⊙⊙ Leaf obviously hairy.
† Hairs more especially above.
Avena flavescens is very similar to Cynosurus, but is evidently hairy, and A. pratensis also comes here.