SOME ANCESTORS OF THE PERSIMMON 17 



today is shown by their similar foliage, as may be seen from a 

 comparison of the leaf of Diospyros primaeva shown in fig. 1 

 alongside of a small leaf of our existing Diospyros virginiana (fig. 

 3). This resemblance is also shown by the fossilized remains 

 of the calices of various species. One of these calices from another 

 early Cretaceous species, recently described by the writer as 

 Diospyros vera and found in what is known in the Potomac River 

 valley, as the Raritan formation, is also shown in fig. 2. Appar- 

 ently the habit of accrescence had not been fully formed but the 

 calyx was persistent then as now and entirely like a modern 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. 



In the Eocene period, which succeeded the Cretaceous, the 

 records of the fossil occurrences of Diospyros, show that it was 

 truly cosmopolitan. These records include Siberia, Alaska and 

 Greenland on the north, Canada, various localities in Europe, 

 as well as Colorado, Montana, Wyoming, Nevada, Oregon, Wash- 

 ington, and other western states. A leaf of one of these early 

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

 we have no Eocene or later Tertiary records along the Atlantic 

 coast of North America since the preserved deposits are all 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 Oligocene 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. 

 The records include Greece, Germany, Italy, Austria, and France 

 and embrace calices or leaves of at least fifteen different species. 

 Especially in southern France where the climate approached sub- 

 tropical conditions, numerous varieties of the persimmon flour- 

 ished along the borders of the shallow gulf which extended up the 

 Rhone valley. In succeeding Miocene time, a period of luxuriant 

 forests, species of persimmon are found throughout Europe. In 



THE PLANT WORLD, VOL. 15, NO. 1, JANUARY, 1912 



