_Anthoxanthum odoratum._ No keel, ridges obsolete, the stronger bundles only with girders. Motor-cells conspicuous between all the ribs. Marginal sclerenchyma, and that above and below the bundles, poorly developed. A few coarse hairs both above and below, and stomata on both faces. Leaf thin and narrow. _Hordeum murinum._ Few girdered bundles, and sclerenchyma at margins poor. Hairs sparse and coarse. _Bromus asper_, _Brachypodium sylvaticum_ and _Lagurus_ also come here. In all these grasses the epidermal cells are chiefly long, rectangular or slightly hexagonal, with thin and plane walls. ⊙⊙ _Hairs none or very rare on the sections._ _Phleum pratense._ Low rounded ribs with motor-cells between. The larger vascular bundles girdered. Stomata about equal on both faces. No hairs. No keel. Marginal sclerenchyma scanty. _Arrhenatherum avenaceum._ Very rare hairs above: a few blunt asperities here and there. No keel. Ridges low. Girders to the primary bundles, but not very strong: marginal and other sclerenchyma faint, as is also the cuticle. Stomata on both faces. Motor-cells fairly developed between the ridges. _Briza media._ No keel, and mere traces of marginal sclerenchyma. Ribs practically obsolete, but well developed motor-cells in furrows. Principal bundles girdered. Stomata on both sides. No hairs or thickened cuticle. _Avena fatua_, _Molinia_ and _Leersia_ also come here. (_b_) Upper and lower leaf-surfaces dissimilar, or at least not parallel, owing to the conspicuous ridges and grooves above. (1) No stomata below. * _Leaves flat or nearly so, or at least exhibit a conspicuous concave upper surface._ ⊙ _Motor-cells between each pair of ribs: sclerenchyma not forming a continuous layer below._ ≡ _Ridges at least 5-6 times as high as the leaf-thickness between._ _Aira cæspitosa._ Ridges high, 7-10 times as high as the breadth of leaf between, triangular, each with 1-3 vascular bundles devoid of girders, with an upper isolated band of sclerenchyma at the acute tip, and another below the principal bundle. Also small bands below each group of motor-cells. Small conical asperities on the ridges and below. No mid-rib. Stomata on flanks of ridges only, and few motor-cells between (Fig. 23). Each vascular bundle has a sheath, but is isolated. Sclerenchyma at tips of the ridges dense: smaller bands below: strong at margins. Lower cuticle strong. Leaf rolls up. The flat upper leaves of _Festuca rubra_ (Fig. 20) and _F. heterophylla_ are somewhat similar in type. They have stiff hairs on the ridges. ≡≡ _Ridges not more than 2-3 times as high as the tissue between; each furrow with motor-cells, and each vascular bundle joined to epidermis above and below by a sclerenchyma girder._