122 HISTOLOGY OF THE GRAIN [CH. 
coats, differing in the number of layers and in the micro- 
scopic characters of the cells, some of which characters 
can be employed in diagnoses. (Fig. 39.) 
Secondly, the great mass of the “grain” internally is 
composed of delicate cells filled in most cases with starch- 
grains, the sizes, shapes and arrangement of which can 
also be employed for diagnoses—e.g. the compound grains 
of the Aveneze and Festucez are different from the simple 
polyhedral or rounded grains of the Andropogonee and 
SEE 
VaR REL ee KS ; 2 ss 
i = hy N Fi 
eee 8 Gia SONA NSS 
’ t A / 
4 nS 
aim 
ot 
a 
eae 
yeaa 
\é ‘Ss 
Fig. 39. Transverse section (highly magnified) through a grain of 
Brachypodium pinnatum taken about half-way up. 1, epidermis; 
2, pericarp; 3, remains of the true seed-coat; 4, vascular bundle; 
5, remains of nucellus; P, epidermis of nucellus; G, aleurone 
layer: remarkable in being several cells thick; E, endosperm. 
Harz. 
Maydee, and some races of Maize have sugar and soluble 
starch instead of grains of the latter. 
