GEOLOGIC HISTORY OF THE LOCUST 291 



a succulent pulp. The water locust is an inhabitant of river 

 bottoms and swamps and attains its maximum size in the bottom 

 swamps and along stream banks in Louisiana and Arkansas. 



No representati\'es of the honey locust can be recognized with 

 certainty in either the Upper Cretaceous or the Eocene, although 

 there are a number of leguminous leaflets found in the rocks of 

 both of these periods that might well represent its ancestors, in 

 fact a genus called Gleditsiophyllum found in both the Upper 

 Cretaceous and the Eocene of North America is suggestivel}' 

 like the honey locust. 



A supposed species is recorded from the Oligocene of Europe 

 and there are a number of undoubted Miocene species. Seven 

 or eight have been described, one occurring on the east coast of 

 Asia and the others all confined to Europe, where they are 

 know^n from Greece and Hungary to France. Thej^ were 

 especially abundant in the Miocene woods of Switzerland in 

 the days before the formation of the Alps had been completed. 

 Pliocene records are wanting in both this country and Europe. 

 The modem species appears in the early Pleistocene of Ken- 

 tucky and an extinct species is recorded from the Interglacial 

 deposits of the Don valley in Ontario. 



THE KENTUCKY COFFEE-TREE {Gijmnocladus) 



Gymnocladus is one of those rather numerous and unrelated 

 genera that at the present time is native only in southeastern 

 North America and southeastern Asia, and Uke the Tulip-tree 

 and the Sassafras it has a single species in each region, scarcely 

 distinguishable from one another, while the ancestral stock has 

 become extinct in the intervening areas. Our American tree is 

 commonly known as the Kentucky coffee-tree or coffee bean, 

 since its seeds were sometuxies used as a substitute for coffee, 

 especially during pioneer and Revolutionary times. It is also 

 called the stump tree in certain localities because the leafstalks 

 are often shed after the leaflets and their large size makes it 

 appear that the tree is shedding its twigs. The fresh green pulp 

 of the unripe pods is still used in homoeopathic practice and the 



