SWEET GUM AND WITCH HAZEL 351 



cies of sweet gum are recorded from Miocene rocks, most of them 

 surprisingly like the modern gum. There are species from Japan 

 on the east and from southwestern asiatic Russia on the west. 

 The European records are innumerable and widely distributed 

 and the American records include Oregon and Colorado. If the 

 reader will turn to the accompanying plate the resemblance of 

 these ancient flowers, fruits and leaves to those of today will be 

 at once apparent. These figures are taken for the most part 

 from the wealth of remains preserved in the tiny Miocene lake 

 of Oeningen on the Swiss border of Baden, and the leaves show 

 the same variation of three, four, five or more lobed forms such 

 as can be matched today in any southern swamp. 



The Miocene was followed by the Pliocene and the gums were 

 still cosmopolitan in the northern hemisphere so that it is easy 

 to see why their distribution is what we find it to be at the pres- 

 ent time. Pliocene gums have been found at very many localities 

 throughout central and southern Europe as well as on our At- 

 lantic coast. I have reproduced a worn gum ball collected from 

 the Pliocene deposits along the Main River in Germany on the 

 accompanying plate, and the fruits found in the late Pliocene of 

 Holland are indistinguishable from those of the existing species 

 of Asia Minor. 



The Pliocene was followed by the Pleistocene or Glacial time 

 and the gums found fossil in this comparatively recent geological 

 period include traces of the existing Formosa and south China 

 species, which then still flourished in Japan, and the abundant 

 leaves and fruits of the existing red gum which have been found 

 in West Virginia, North Carolina and Alabama. A leaf and 

 fruit from the Pleistocene swamp deposits along the Neuse River 

 in North Carolina are shown on the plate. 



That the gums which were so abundant throughout Europe in 

 the late Tertiary should have been entirely exterminated by the 

 glacial conditions while they survived in North America and 

 Asia seems strange but is readily understood when it is recalled 

 that high mountains and seas from the Pyrenees to the Caucasus 

 made it impossible for the gums to escape southward to more 

 genial climes and to return to the northward again when the cold 



