THE ELM, PLANER AND IIACKBERRY 149 



Newfoundland and the Great Lakes to the foothills of the Rockies, 

 and southward to Florida, being smaller toward its southern limits 

 and confined to stream banks in the prairie States. 



The rock or cork elm, Ulmus racemosa, is a northern form with a 

 corky bark, of our northern states and southern Canada; and the 

 Wahoo or winged elm, Ulmus alata, is a similar corky species of 

 our southern states, in which it is frequently planted as a shade 

 tree. The red or slippery elm, Ulmus fulva, is famihar to every 

 rural boy of our eastern states because of its thick fragrant inner 

 bark, which is very mucilaginous and affords dehghtful chewing 

 in the spring time when the sap is flowing. It is used to som^e 

 extent in medicine as a demulcent for inflammatory affections. 



Our tv/o other American elms — the cedar elm, Ulmus crassifolia, 

 and the red elm, Ulmus serotina, differ from the others in flowering 

 in the autmnn instead of the spring, a habit correlated with their 

 southern range. They are both fair sized trees occasionally planted 

 as shade trees in Texas, Alabama and Georgia, and with restricted 

 natural ranges in that general region. They will be unfamiliar to 

 most of my readers. 



A large number of fossil elms have been described and a few of 

 these have been reproduced in the accompanying figures. It is 

 not always possible to distinguish with certainty between elms and 

 hornbeams or iron-wood when the leaves only are preserved as 

 fossils. There is no positive evidence of the presence of elms in 

 the forests of Upper Cretaceous times and elms are thus somewhat 

 later in appearing in the geological record than are the ancestors 

 of the related planer tree, or than are the ancestors of many of 

 our other forest trees. The name Ulmus has been applied to 

 fossils from the Upper Cretaceous rocks of western Canada, but 

 these are not recognized as true elms. That ancestral elms were 

 already in existence somewhere during Upper Cretaceous time is 

 rendered almost certain by their abundance and wide distribution 

 in the rocks of the early Tertiary, or Eocene. 



Twenty-eight Eocene elms have been described. Several of 

 these are from the earhest deposits of that time, often called 

 Paleocene, and the reason that we think that the ancestral stock 



