The _apex_ is in most cases slender and tapering--_acuminate_; but in some it is merely brought to a point (_acute_) as in _Catabrosa_, _Glyceria_ and several species of _Poa_ and _Avena_, &c., usually flat, but somewhat hooded or curved up in some Poas. In cases where the leaves are _setaceous_ or _subulate_, the apex is like a thin tapering bristle, and even flatter leaves may be so inrolled at the tips as to have the apex prolonged into a sharp needle-like _pungent_ or _spinescent_ point--e.g. _Hordeum pratense_, _Avena pratensis_ to a slight extent, and pronounced in _Elymus_, &c. In _Sesleria_ the apex is rounded with a short, sharp, prickle-like median projection (_mucronate_). The passage of blade into sheath has already been described, but the base of the blade may have its margins projecting as horizontal shelves, like a Byron collar, round the sides of the throat of the sheath, sometimes tinged with yellow or pink--e.g. _Lolium_, _Holcus_, _Bromus inermis_, _Hordeum_; the ends of these may project as _auricles_ or ears--e.g. _Festuca elatior_, _Elymus_, _Agropyrum_, _Anthoxanthum_, _Bromus asper_, _Hordeum_, &c. In _Festuca ovina_ the ears are short, stiff, and erect (Fig. 13). The margin may be perfectly even, as in most grasses, or it is more or less _scabrid_ or _scaberulous_, as in _Aira cæspitosa_, _Poa maritima_, _Festuca elatior_, _Avena pratensis_, _Agrostis_, _Milium_, _Phleum_, _Briza_, the minute teeth (_serrulæ_) pointing up or down. The surface may be bright green, or glaucous, harsh, hairy or glabrous, and is not uncommonly also _scabrid_, like a file or emery-paper, and sometimes only when rubbed in one direction up or down, owing to the minute teeth being directed all one way. These teeth are developed on the ridges. All our ordinary grass leaves are parallel-veined, and the vascular strands (the veins) can usually be seen on holding the leaf up to the light. In most cases the tissue is raised over the veins, as ridges or “ribs,” and according to the height of these ridges the thinner parts between look like deep or shallow furrows (cf. Figs. 8-16 and Chapter IV.). If the leaf is held up to the light the ridges appear _dark_ in proportion to their opacity--i.e. height or thickness--and the furrows _light_ in proportion to the thinness of the tissues there. If the contrast is very great, as in _Aira cæspitosa_ (Fig. 23), the furrows seem like transparent sharp lines, and when, as in _Poa_, which is practically devoid of ridges, the difference of thickness is small they appear merely as fine striæ. These characters must be determined on the fresh leaves, however, because the contraction in drying draws the ridges closer together and tends to obliterate the lines. [Illustration: Fig. 14. _Digraphis arundinacea._ Transverse section of mid-rib and half the leaf (× about 6).] [Illustration: Fig. 15. _Holcus lanatus._ Transverse section of leaf-blade (× 10).]