FRUIT 1§ 
this anemophilous mode of pollination. The flowers are incon- 
spicuous ; the perianth (which in most other plants whose flowers 
are pollinated by insects, is large, brightly coloured, and so attrac- 
tive) is in grasses which do not require the services of insects, 
reduced to microscopic size, and the flowers are protected by green 
uninviting bracts ; the large anthers contain a copious quantity 
of pollen for dispersion broadcast, and the 
large feathery stigmas readily catch the pollen 
grains as they are wafted on the wind; more- 
over, as the grass-flower has only one ovule, 
asingle pollen grain suffices for its fertiliza- 
tion. Pollination is thus amply provided for ; 
and a second staminal whorl, being unneces- 
sary, is usually suppressed. 
The process of fertilization of the ovule, 
which takes place quickly after pollination, 
is the same in grasses as in all other Azgéo- 
spermts, Ze. plants whose ovules are enclosed 
in an ovary. The seed is ordinarily matured 
in the course of three or four weeks, the wall 
of the ovary becomes thin and dry, but ad- 
heres firmly to the solitary seed, and con- 
stitutes the pericarp (fig. 12). Such a fruit is 
termed a grain or caryopsis ; for, convenient 
though it be to speak of the grains as seeds, 
this 1s not botanically correct. The cary- 
opsis is very similar to the nut, but differs 
from it in having the pericarp adherent. The 
pericarp does not rupture until germination 
takes place; in other words, the fruit is ‘in- 
dehiscent. Sporobolus is one of the rare in- 
Vitti) 
Se 
Fic. 12.—Cross-section 
stances of a free pericarp which, in this genus, 
splits into two portions or valves to allow the 
seed to escape. The seed has a very thin 
coat or testa (fig. 12, 27 and z), and contains 
an unusually large quantity of endosperm. 
The position of the embryo, in relation to 
the endosperm, we have already noticed at 
the beginning of this chapter. It will be 
observed that in consequence of the inversion 
of the ovule, the radicle of the embryo is 
directed towards the base of the grain. 
through the pericarp and 
testa of a grain (x 240); 
ep epicarp; ¢ outér layers, 
and ch/ chlorophyll layer, 
together constituting the 
pericarp; 7, remains of 
the ovular integuments, 
and 2, layer of nucellus, 
form the testa ; aZ outer- 
most layer of endosperm 
cells. 
We shall have something 
to say about the endosperm as a nutrient substance, when treating 
of the uses of grasses. In form, the grain may be ovoid, oblong, 
or spindle-shaped ; it has often a longitudinal groove on one side, 
corresponding to the place where, in the development of the flower, 
the edges of the carpellary leaves cohered (the ventral suture) to 
form the ovary. 
The fruit is liberated in various ways. When the inflorescence 
is a jointed spike, as in Hordeum and Lepturus, the rachis (axis of 
