Secondary roots
sometimes spring from the lower surface of the peg, which thus seems in all
respects to partake of the nature of the radicle. The peg is always
developed on the side which becomes concave by the arching of the
hypocotyl; and it would be of no service if it were formed on any other
side. It is also always developed with the flat lower side, which, as just
stated, forms a part of the radicle, at right angles to it, and in a
horizontal plane. This fact was clearly shown by burying some of the thin
flat seeds in the same position as in Fig. 62, excepting that they were not
laid on their flat broad sides, but with one edge downwards. Nine seeds
were thus planted, and the peg was developed in the
[page 104]
same position, relatively to the radicle, as in the figure; consequently it
did not rest on the flat tip of the lower half of the seed-coats, but was
inserted like a wedge between the two tips. As the arched hypocotyl grew
upwards it tended to draw up the whole seed, and the peg necessarily rubbed
against both tips, but did not hold either down.
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