. Elements of geology, or, The ancient changes of the earth and its inhabitants as illustrated by geological monuments. Geology. 252 UPPER MIOCENE FLORA OF (ENINGEN. [Ch. XV. poplars and willows, countless leaves of which became imbedded in the mud. Together with them, at some points, a species of reed, Arundo, was very common. One of the most characteristic shrubs is a papilionaceous and legu- minous plant of an extinct genus, called by Heer Podogonium, of which two species are known. Entire twigs have been found (a, fig. 180), with flowers, and always without leaves, the flowers having evi-
. Elements of geology, or, The ancient changes of the earth and its inhabitants as illustrated by geological monuments. Geology. 252 UPPER MIOCENE FLORA OF (ENINGEN. [Ch. XV. poplars and willows, countless leaves of which became imbedded in the mud. Together with them, at some points, a species of reed, Arundo, was very common. One of the most characteristic shrubs is a papilionaceous and legu- minous plant of an extinct genus, called by Heer Podogonium, of which two species are known. Entire twigs have been found (a, fig. 180), with flowers, and always without leaves, the flowers having evi- dently come out, as in the poplar and willow tribe, before any leaves made their appearance. Other specimens have been obtained with ripe fruit accompanied by leaves, as shown in the branch b, fig. 180. In some specimens are seen the embryo and cotyledons, in others the calyx and young fruit. The leaves resemble those of the tamarind, but each pod contains only a single seed, whereas the pod of the tamarind, an allied genus, contains many seeds. In fig. 181 we see a ripe seed-vessel of this plant, and on the same thin slab a winged ant, c, Formica lignitum, Heer. Another species of ant, also with wings, has been found associated with the same Podogonium in fructification, from which fact Professor Heer con- cludes that it ripened its seed, in summer, at which season alone swarms of perfect male and female ants, having their wings fully developed, make their flights. Such, for example, is the habit of the living Formica herculeana, which comes very near to F. lignitum. In the same slab, at d, is a portion of a beetle of the genus Hister. The Upper Miocene flora of OEningen is peculiarly important, in consequence of the number of genera of which not merely the leaves, Fig. Acer trilobatum, normal form. Heer, Flora Tert. Helv., pi. 114, fig. 2. Size $ diam. (Part only of the long stalk of the original fossil specimen is here given.) Upper Miocene, (Eningen; also found in Low
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Keywords: ., bookcentury1800, bookdecade1860, booksubjectgeology, bookyear1868
