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the Grain of Wheat ( Triticum vulgare). 
some cells in the flanks begin to show small starch grains, congregated 
almost entirely round the nuclei, which are large and well developed, in full 
activity. Further away from the embryo the starch in the flanks increases 
in amount, while a certain quantity gradually fills in across the bridge, 
but is at first confined to the side next the furrow, only spreading 
outwards lower down the series. At the extreme end of the grain a 
fair amount of starch is present, though right up to the end there is less 
towards the outer side of the bridge than in the flanks, or on that side of 
the bridge next the furrow. 
During the next three or four days the infilling of reserve material 
makes rapid strides. Starch is now found in the flanks right up to the level 
of the embryo, and at this stage it also occurs across the bridge, next to the 
furrow. The carbohydrate rapidly extends outwards, till a short distance 
down the whole endosperm is filled in. 
From this time onwards no radical change takes place. The starch 
appears to get more dense and gradually fills up the cells on the outer side 
of the bridge adjacent to the embryo. Five weeks after pollination the 
infilling may be regarded as practically complete, judging by microscopical 
tests, though there are usually one or two rows of much deformed cells on 
the outer side destitute of starch all the way through, which have been 
crushed back by the developing embryo. It is just at this time that the 
grain begins to change its colour from green to brown, after which it takes 
about another fortnight to become properly ripe. 
When one comes to consider the manner in which the reserve starch is 
packed into the cells, there are certain points which are somewhat contrary 
to one’s expectations. The wheat ovule is anatropous, and therefore 
a conducting strand runs up the raphe alongside the seed, at the base 
of the furrow, and so one would naturally expect that insoluble carbo- 
hydrate would first be laid down in the cells at the extreme limit of the 
grain, as actually happens. The flanks of the endosperm, where the first 
vestiges of starch occur, continue to keep the lead, as, at any level, it is 
always the cells in this position which first reveal starch grains. Then, 
instead of the soluble carbohydrate being carried across the width of the 
endosperm, and being finally deposited in the first place at the outer edge 
of the grain, thus leaving a clear passage behind it, the cells which first 
deposit their starch are those nearest to the furrow, and therefore to the 
conducting strand. This makes the percolation of the soluble reserves 
much more difficult, and, judging by the appearance presented by the 
various series of sections, it seems probable that the infilling does not only 
take place laterally, but also in an obliquely downward direction. This 
implies that soluble reserves are brought to a certain point in the con- 
ducting strand — thence some probably pass into the endosperm obliquely 
downwards, filling up the cells at a lower level which have been blocked 
K 
