[Illustration: Fig. 124. Larch. A and B, young scales, showing (~i~)
inner seed-bearing scale, and (~o~) outer protective one. A, side view;
B, front view; C and D, old scales, C from the side, D from the front,
showing how the inner scale increases more rapidly than the outer.]
5. ~The seeds are always seen to be lying quite openly on the upper
side of the scales, and are not covered in by closed carpels~ as they
are in the flowering plants. Each of the scales (which bears its two
seeds) corresponds in a way to the carpel in a flower, but there is
an important difference in the fact that it leaves the seeds open. In
old pine cones there seems to be only one scale to each pair of seeds,
but there is really a second smaller one outside it--which is sometimes
quite difficult to see. It shows better in the larch, where the outside
one is much the bigger of the two in the young cones, and gradually
gets left behind, as the inner scale grows very fast (~see~ fig. 124).
Notice, too, how the ripe seeds have one-sided wings, which split off
from the inner scale, as you can see if the cone is not too ripe. This
~wing is on the seed itself~, not on a fruit, as is often the case
among the flowering plants. The wing helps the seed to fly, and in the
late autumn (in many cases two years after it began to grow, for some
pines grow very slowly) it is scattered with its brothers. If you are
ever near pine trees when there has been snow, you may see it sprinkled
with these winged brown seeds.
[Illustration: Fig. 125. Winged seed of the Pine.]
6. You may never have seen a baby pine tree. If not, you must get some
seeds and grow them. They grow very slowly at first, and may take six
weeks to show above ground even in summer; but they are well worth
waiting for. Notice how they come up (~see~ fig. 126), and that at
the beginning of their growth, as they come out from the seed, they
have seven or even as many as twelve first leaves, and these leaves
are really the cotyledons, as you may see by cutting a seed across. So
that instead of the one or two cotyledons of the flowering family, we
find in the pine family that ~there are many cotyledons, and that their
number may vary from five to ten or more~.
[Illustration: Fig. 126. Stages in the growth of Pine seedlings; (~c~)
cotyledons.]
If you go back over these points, you will see that we have found a
large number of differences between the flowering plants and the pines.
Of these, the most important are the points (5) and (6), which alone
would be enough to make us place the pines and flowering plants in
separate families, though point (4) is also very important. We find,
however, that the pines are more like the flowering plants than are
any of the other families, so that they are the nearest relatives the
flowering plants have, even though they are rather far-away ones.
[Illustration: PLATE III.
TREE FERNS, SHOWING THEIR TALL THICK TRUNKS AND LARGE LEAVES, WITH
SMALLER FERNS GROWING BENEATH THEM]
Public-domain text, read in full here on John Shaqi.
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