the Grain of Wheat ( Triticuni vulgar e). 13 7 
but these divide up till eventually about a dozen are present, and the leaf 
shows definite ribbing on its inner side. Traces of vascular tissue can 
also be made out in the second leaf by the time its development is com- 
pleted. 
When the seed germinates the radicle first shows itself, pushing its 
way through the tissues of the coleorhiza, which remains as a sheath at 
its base. The two pairs of lateral rootlets appear at intervals, the lowest 
pair first, and rapidly elongate till they are soon as well marked as the 
main root. Very much later the solitary fifth rootlet emerges, coming out 
from between the upper pair of laterals. No tap-root is formed, since the 
adventitious rootlets develop as strongly as the radicle, and so a fibrous 
root system is ultimately the result. 
Summary. 
1. No cytological differences can be observed between wheat grains of 
different varieties, grown under similar conditions, which produce flour 
of varying strengths. 
2. No cytological differences, indicative of strength, are to be found in 
the developing grains of one variety of wheat, when grown in the same field, 
on similar soil, and under the same climatic conditions, but subject to radical 
differences in manuring. 
3. The reputed difference in strength between grains of the same 
variety, grown under the same conditions, but cut ‘ green ’ and c dead ripe 
is not associated with any significant cytological change. 
4. Examination of the different grades of flour obtained during the 
various processes of roller milling show that the cells of the aleurone layer 
very rarely get into the flour, but remain attached to the bran in small 
sheets. 
5. The endosperm arises in the first place by free-cell-formation, 
but after about a week wall-formation begins, starting from the periphery 
of the embryo-sac and proceeding inwards, while the central vacuole fills 
up first at the micropylar end. The peripheral layer is marked off about 
a fortnight after pollination, and develops into the aleurone layer. 
6. Deposition of starch grains begins in the middle of the flanks of 
the endosperm at the lower end of the grain, and proceeds upwards and 
outwards. In the bridge the cells nearest the furrow are the first to fill up, 
the deposition proceeding from this point towards the dorsal side of the 
grains. Reserve nitrogenous material enters at the same time as the 
starch. 
7. During the process of maturation, disorganization of endosperm 
nuclei takes place, caused by the increasing pressure of the surrounding 
food substances, which is largely due to the desiccation going on at this 
stage. The nuclei lose their nucleoli, become deformed, and finally 
