The Geological History of PlantsDawson, John William, Sir
Science
The Geological History of Plants
Dawson, John William, Sir
Paleobotany
"Three species of _Liriodendron_ are indicated by leaves found in the
Amboy clays--Middle Cretaceous--of New Jersey, and others have been
obtained from the Dakota group in the West, and from the Upper Cretaceous
strata of Greenland. Though differing considerably among themselves in
size and form, all these have the deep sinus of the upper extremity
so characteristic of the genus, and the nervation is also essentially
the same. Hence, we must conclude that the genus _Liriodendron_, now
represented by a single species, was in the Cretaceous age much more
largely developed, having many species, and those scattered throughout
many lands. In the Tertiary age the genus continued to exist, but
the species seem to have been reduced to one, which is hardly to be
distinguished from that now living. In many parts of Europe leaves of
the tulip-tree have been found, and it extended as far south as Italy.
Its presence there was first made known by Unger, in his 'Synopsis,'
page 232, and in his 'Genera et Species,' page 443, where he describes
it under the name of _Liriodendron procaccinii_. The genus has also been
noticed in Europe by Massalongo, Heer, and Ettingshausen, and three
species have been distinguished. All these are, however, so much like the
living species that they should probably be united with it. We here have
a striking illustration of the wide distribution of a species which has
retained its characters both of fruit and leaf quite unchanged through
long migrations and an enormous lapse of time.
"In Europe the tulip-tree, like many of its American associates, seems
to have been destroyed by the cold of the Ice period, the Mediterranean
cutting off its retreat, but in America it migrated southward over the
southern extension of the continent and returned northward again with the
amelioration of the climate."
Leaves of _Liriodendron_ have been recognised in the Cretaceous of
Greenland, though it is now a tree of the warm temperate region, and
Lesquereux describes several species from the Dakota group. But the genus
has not yet been recognised in the Laramie or in the Upper Cretaceous of
British Columbia. In the paper above quoted, Newberry describes three new
species from the Amboy clays, one of which he considers identical with a
Greenland form referred by Heer to _L. Meekii_ of the Dakota group. Thus,
if all Lesquereux's species are to be accepted, the genus begins in the
Middle Cretaceous with at least nine American species.
In New Jersey the Amboy clays are referred to the same age with the
Dakota beds of the West. In these Dr. Newberry has found a rich flora,
including many angiosperms. The following is condensed from a preliminary
notice in the "Bulletin of the Torrey Botanical Club":[DO]
[DO] March, 1886.
Public-domain text, read in full here on John Shaqi.
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