The story of the universe. Volume 3 (of 4) : $b The earth's garment : flora — John Shaqi
The story of the universe. Volume 3 (of 4) : $b The earth's garment : flora
History
The story of the universe. Volume 3 (of 4) : $b The earth's garment : flora
Astronomy; Earth (Planet); Natural history
In this period also we find the earliest representatives of the
endogenous plants. It is true that some plants found in the
coal-formation have been doubtfully referred to these, but the
earliest certain examples would seem to be some bamboo-like and
screw-pine-like plants occurring in the Jurassic rocks. Some of
these are, it is true, doubtful forms, but of others there seems to
be no question. The modern _Pandanus_ or screw-pine of the tropical
regions, which is not a pine, however, but a humble relation of the
palms, is a stiffly branching tree, of a candelabra-like form, and
with tufts of long leaves on its branches, and nuts or great hard
berries for fruit, borne sometimes in larger masses, and so protected
as to admit of their drifting uninjured on the sea. The stems are
supported by masses of aerial roots like those which strengthen the
stems of tree-ferns. These structures and habits of growth fit the
Pandanus for its especial habitat on the shores of tropical islands,
where its masses of nuts are drifted by the winds and currents, and
on whose shores it can establish itself by the aid of its aerial
roots.
Some plants referred to the cycads have proved veritable botanical
puzzles. One of these, the _Williamsonia gigas_ of the English
oölite, originally discovered by my friend, Dr. Williamson, and
named by him _Zamia gigas_, a very tall and beautiful species, found
in rocks of this age in various parts of Europe, has been claimed
by Saporta for the Endogens, as a plant allied to _Pandanus_. Some
other botanists have supposed the flowers and fruits to be parasites
on other plants, like the modern _Rafflesia_ of Sumatra, but it is
possible that after all it may prove to have been an aberrant cycad.
The tree-palms are not found earlier than the Middle Cretaceous. In
like manner, though a few Angiosperms occur in rocks believed to
be Lower or Lower Middle Cretaceous in Greenland and the Northwest
Territory of Canada, and in Virginia, these are merely precursors of
those of the Upper Cretaceous, and are not sufficient to redeem the
earlier Cretaceous from being a period of pines and cycads.
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