ass and the kolakattai grass. But
in the grass family or Gramineae the cereals, sugarcane and bamboos are
also included.

Grasses are rather interesting in that they are usually successful in
occupying large tracts of land to the exclusion of other plants. If we
take into consideration the number of individuals of any species of
grass, they will be found to out-number those of any species of any
other family. Even as regards the number of species this family ranks
fifth, the first four places being occupied respectively by Compositae,
Leguminosae, Orchideae and Rubiaceae.

As grasses form an exceedingly natural family it is very difficult for
beginners to readily distinguish them from one another.

The leaves and branches of grasses are very much alike and the flowers
are so small that they are liable to be passed by unnoticed. The
recognition of even our common grasses is quite a task for a botanist.

To understand the general structure of grasses and to become familiar
with them it is necessary to study closely some common grasses. We shall
begin our study by selecting as a type one of the species of the genus
Panicum.

_Panicum javanicum_ is an annual herb with stems radiating in all
directions from a centre. The plant is fixed to the soil by a tuft of
fibrous roots all springing from the bases of the stems. In addition to
this crown of fibrous roots, there may be roots at the nodes of some of
the prostrate branches. The stems and branches are short at first, and
leaves arise on them one after the other in rapid succession. After the
appearance of a fair number of leaves the stem elongates gradually and
it finally ends in an inflorescence.

[Illustration: Fig. 1.--Panicum javanicum. (Full plant.)]

The stem consists of =nodes= and =internodes=. The internodes are
cylindrical and somewhat flattened on the side towards the axillary bud.
When young they are completely covered by the leaves and the older ones
have only their lower portions covered by the leaf-sheaths. Usually they
complete their growth in length very soon, but the lower portion of the
internode, just above the node and enclosed by the sheath, retains its
power of growth for some time.

The leaf consists of the two parts, the =leaf-sheath= and the
=leaf-blade=. At the junction of these two parts there is a very thin
narrow membrane with fine hairs on its free margin. This is called the
=ligule=. (See fig. 2.)

The leaf-sheath is attached at its