minutely serrate and ciliate.]

In grasses the leaf-blades usually grow more in length than in any other
direction and there is no limit to the length they may attain. Some
grasses have very short leaves, others very long ones. The leaf-blade in
most grasses is more or less of some elongated form, such as linear,
linear-lanceolate, lanceolate, etc. (See fig. 14.) In a few grasses the
leaf-blade is ovate, but this is a rare condition. Therefore, in noting
the general shape of the leaf-blade the relation of the length to the
breadth, the amount of tapering towards the apex and base and the nature
of the apex should be considered.

The veins in the leaf-blade can usually be seen on holding the leaf up
to the light. All the veins run parallel. In most cases the midrib is
prominent and in some cases there may be also a distinct keel. Amongst
the veins running through the leaf-blade some are large and prominent,
while others are small and not conspicuous. On account of this
disparity, very often, ridges and furrows become prominent on the upper
or lower, or on both the surfaces of the leaf-blades. Generally the two
surfaces of the leaf-blade are distinct, and they may be glabrous or
hairy. In most grasses the surfaces are rough or scabrid to the touch
owing to the presence of regular rows of exceedingly fine sharp pointed
minute hairs.

The apex of the blade is generally sharp and pointed, acute or
acuminate, or sometimes it may be drawn to a very fine point by gradual
tapering. Blunt or obtuse tips are not altogether absent, but it is not
a common feature. The leaf-blades in _Panicum colonum_ and in some
species of Andropogon are rounded or obtuse at the apex.

The margins of the leaf-blade are somewhat hyaline and they may be
perfectly even or cut into serrations of fine teeth in various ways.
(See fig. 15.) In addition to these minute teeth, there may be long or
short cilia. Sometimes the margins are glandular as in _Eragrostis
Willdenoviana_ and _Eragrostis major_.

The base of the leaf may be narrower, broader than, or about the same as
the breadth of the leaf-sheath. It may be rounded, amplexicaul or
narrowed. At the base and just above the ligular region there will
always be a white distinct zone in the lamina of all grasses called the
collar. This collar varies in length and breadth according to the
species of grass.

[Illustration: Fig. 16.--Transverse section of leaf-buds.

A. Conduplicate; 1, 2 and 3. leaf-