No distinct catalogues of plants found in the Pliocene,
or most recent periods of the Tertiary series, have yet been
published.
the natural course of vegetation; there are also branches with leaves on them, such as may have been torn from trees by stormy weather; ripe seed vessels; and the persistent calix of many blossoms.
The greater part of the fossil plants at Œningen (about two thirds) belong to Genera which still grow in that neighbourhood; but their species differ, and correspond more nearly with those now living in North America, than with any European species, the fossil Poplars afford an example of this kind.
On the other hand there are some Genera, which do not exist in the present Flora of Germany, e. g. the Genus Diospyros; and others not in that of Europe, e. g. Taxodium, Liquidambar, Juglans, Gleditschia.
Judging from the proportions in which their remains occur, Poplars, Willows, and Maples were 'the predominating foliaceous trees in the former Flora of Œningen. Of two very abundant fossil species, one, (Populus latior,)resembles the modern Canada Poplar; the other, (Populus ovalis) resembles the Balsam Poplar of North America.
The determination of the species of fossil Willows is more difficult. One of these (Salix angustifolia) may have resembled our present Salix viminalis.
Of the genus Acer, one species may be compared with Acer campestre, another with Acer pseudo plat anus; but the most frequent species, (Acer pro tens urn,) appears to correspond most nearly with the Acer dasycarpon of North America; to another species, related to Acer negundo, Mr. Braun gives the name of Acer trifoliatum. A fossil species of Liquidambar (L. europeum, Braun.) differs from the living Liquidambar styracifluum of America, in having the narrower lobes of its leaf terminated by longer points, and was the former representative of this genus in Europe. The fruit of this Liquidambar is preserved, and also that of two species of Acer and one Salix.
The fossil Linden Tree of Œningen resembled our modern large-leaved Linden tree (Tilia grandillora.)
The fossil Elm resembled a small leaved form of Ulmis campestris.
Of two species of Juglans, one (J. falcifolia) may be compared with the American J. nigra; the other, with J. Alba, and, like it, probably belonged to the division of nuts with bursting' external shells, (Carya Nuttal.)
Among the scarcer plants at Œningen, is a species of Diospyros (D. brachysepala.) A remarkable calyx of this plant is preserved, and shows in its centre, the place where the fruit separated itself: it is distinguished from the living Diospyros lotus of the South of Europe by blunter and shorter sections.
