CHAPTER I 
Structure 
WHILE perusing this chapter, the student should have before him 
some flowering specimens of grasses, also some large grains, say 
wheat, oats or barley, in order that he may verify our statements 
by his own observation. 
We propose to begin with the examination of the tiny grass- 
plant in the seed, selecting a grain of wheat for the purpose of 
illustration. Of the grain, regarded as a fruit, we shall speak later, 
confining our attention at present to the living part or embryo, 
which is very small in comparison to the mass of floury endosperm 
stored up for its nourishment and forming the bulk of the grain. 
The exact position of the embryo is indicated by a minute wrinkled 
depression of the skin near the base of the grain (the apex is known 
by its having a crest of short hairs), and on the dorsal side opposite 
to the grooved or furrowed side. It is not embedded in the endo- 
sperm, but lies on the outside of it immediately underneath the 
skin. Before proceeding to examine the embryo, it is advisable to 
soften the grain by soaking it in water for a few hours. The 
embryo can then be easily detached, but the best way to observe 
it is in a longitudinal section like that represented in the accom- 
panying figure. Such a section is obtained by halving the grain 
with a sharp knife lengthwise along the furrow. The embryo is 
now seen to be much longer than broad, and situated rather 
obliquely in respect to the axis of the grain. With the aid of a 
lens we can clearly distinguish, in the upper portion, the plumule 
with several leaf rudiments, the whole enclosed in a sheath known 
as the cotyledon ; in the lower portion we recognise the radicle 
or young root, invested also by a sheath (coleorhiza) ; both these 
sheaths can best be seen in a grain that is germinating. The 
embryo is completely separated from the endosperm by a broad 
plate of tissue termed the scutellum (Lat. scz¢um, a shield), which 
calls for special notice, as it is peculiar to grasses and performs an 
important function at the time of germination. It is in organic 
connection with the rudimentary stem, and, by means of various 
ferments, dissolves the endosperm and then absorbs it for assimi- 
lation by the embryo. A better view of the scutellum can be 
obtained by detaching the embryo from a whole grain. 
The phenomenon of germination is very interesting, and in 
order to observe it, we may experiment with some of the larger 
grains above-mentioned, also those of Phalaris canariensis, the 
“canary-seed” used for feeding cage-birds. Place the grains in 
