184 
ORDER DIGYN1A. 
husk of two valves. These husks constitute the chaff', which is 
separated from the seed by an operation called threshing. 
These little flowers, which are also furnished with a nectary, 
are green, like the rest of the plant, and you will need a micros- 
cope to view them accurately ; they are best observed in a ma- 
ture stage of the plant, when their husks, expanded, discover 
their three filaments, containing each a large double anther; 
their two pistils have a kind of reflected, feathered stigma. 
They have no seed vessel ; each seed is contained within the 
husks, which gradually open ; and unless the seed is gathered 
in season, it 'falls to the ground. This facility for the distribu- 
tion of the seed is one cause of the very general diffusion of 
grasses. 
The roots of grasses are fibrous, and increase in proportion 
as the leaves are trodden down, or consumed ; and the stalks 
which support the flower are seldom eaten by cattle, so that the 
seeds are suffered to ripen. Some grasses which grow on very 
high mountains where the heat is not sufficient to ripen the 
seed, are propagated by suckers or shoots, which rise from the^» 
root, spread along the ground, and then take root themselves ; 
grasses of this kind are called stoloniferons , which means bear- 
ing shoots. Some others are propagated in a manner not less 
wonderful ; for the seeds begin to grow while in the flower it- 
self, and new plants are there formed, with little leaves and 
roots ; they 7 then fall to the ground, where they take root. Such 
grasses are called viviparous , which signifies producing their 
offspring alive, either by bulbs instead of seeds, or by seeds 
germinating on the plant. The seeds of the grasses have but 
one lobe, or are not naturally divided into parts, like the apple 
seed and the bean ; therefore these are said to have but one coty- 
ledon. 
The stamens of gramineous plants like all monocotyledons, 
are of that kind which grow internally, or from the centre out- 
ward, and are therefore called endogenous. 
With regard to the duration of the grass-like plants, some are 
annual ; as, wheat, rye, and oats, their roots dying after the 
grain or seed is matured. The meadow grasses are perennial ; 
their herbage dying in autumn, and the roots sending out new 
leaves in the spring. 
The grasses are distributed into a great number of genera, 
chiefly distinguished by the different forms of the corollas, and 
the shape of the valves. 
The essential character of the oat, (Avena,) consists in the 
jointed, twisted awn or beard which grows from the back of the 
Roots of the grasses — 
