22 BASE, MARGIN, SURFACE [CH. 
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. Loliwm, Holcus, Bromus inermas, 
Hordeum; the ends of these may project as auricles or 
ears—e.g. Festuca elatior, Elymus, Agropyrum, Antho- 
zanthum, 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 
cespitosa, Poa maritima, Festuca elatior, Avena pratensis, 
Agrostis, Milium, Phleum, briza, the minute teeth (ser- 
rule) 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 ight. In most cases the tissue 
is raised over the veins, as ridges or “ribs,” and according 
