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Family Pinaceae
The British flora is singularly poor in coniferous
plants, the Scots Pine, the Juniper, and the Yew
being our only native species.
The principal feature distinguishing all Conifers
and their allies (Gymnosperms) from other flowering-plants
(Angiosperms) is briefly this: Angiosperms have
their incipient seeds (ovules) enclosed in a carpel,
through which a shoot from the pollen grain has
to penetrate in order to reach and fertilize the
ovule. In Gymnosperms the carpel takes the form
of a leaf or bract, upon which the naked ovule
lies open to actual contact with the pollen grain.
After fertilization the carpel enlarges to protect
the seed, and becomes fleshy or woody, in the
latter case a group of carpels forming the well-known
cones of Pine or Fir.
In some of the groups the male or pollen-producing
flowers are borne by a separate tree from that
which bears the female or cone-producing flowers.
In the Pines both sexes are found on the same
tree; and in all Conifers the pollen is carried
by the wind. They are among the most valuable
of timber trees, and, in addition, yield a number
of useful substances, such as pitch, tar, turpentine,
etc.
The linear leaves are always rigid, extremely
narrow, and long in proportion, with the two sides
parallel. In the Pines they are in clusters of
two, three, or five, seeming to be bound together
at the base by a wisp of thin skin. The number
of leaves in each bundle is often a help in distinguishing
species.
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