258 TREE ANCESTORS 



leaf of our existing Diospyros virginiana (fig. 3) . Tliis resemblance 

 is also sho\\Ti by the fossilized remains of the cahces of various 

 species. One of these calices from another early upper Cretaceous 

 species, recently described by the writer is Diospyros vera and found 

 in what is knowm in the Potomac River valley, as the Raritan 

 formation is also shown in figure 2. Apparently the habit of 

 accrescence had not been fully formed but the calyx was persistent 

 then as now and entirely like a modem calyx in appearance. It 

 was four-parted as it usually is in existing persimmons but other 

 fossil forms had a five-parted calyx like a good many present day 

 tropical species. This feature is well shown in a large fossil calyx 

 found recently in the upper Eocene of southwestern Texas (fig. 7). 



In the Eocene period, which succeeded the Cretaceous, the rec- 

 ords of the fossil occurrences of Diospyros, show that it was truly 

 cosmopolitan. These records include about 20 species in Siberia, 

 Alaska and Greenland on the north, Canada, various localities in 

 Europe, as well as Colorado, Montana, Wyoming, Nevada, Oregon, 

 Washington, and other western states and the Canal Zone on the 

 South. In beds of supposed Eocene age in Panama many fruits 

 of a persimmon have been discovered in a petrified condition 

 in the andesitic tuffs. These fruits are about the size of cherries 

 with a hard, very tanniferous and more or less fibrous flesh, 

 and 8 to 10 varyingly developed seeds. So far as I know this 

 is the only petrified persimmon fruit known. Two sections of 

 these fruits are shown in figures 8 and 9. A leaf of one of the early 

 Eocene forms from Montana is shown in figure 4. Unfortunately, 

 we have no Eocene or later Tertiary records along the Atlantic 

 coast of North America north of Panama since the preserved 

 deposits are all largely of marine origin and contain no fossil 

 plants. There is little doubt, however, that Diospyros continued 

 to be an abundant element in the arborescent flora of this area. 



The Eocene was succeeded by the geological period known as 

 the OHgocene in the rocks of which age no fossil plants have thus 

 far been discovered in this country. In Europe, where the Oligo- 

 cene is marked by a warm temperate climate and by shallow lake 

 and river deposits, the remains of Diospyros are very common. 



