30 QUERCUS UNDULATA. 



Plate XV, Figure i. 



This is borrowed from the Botany of the Sitgreaves Expedition, as Dr. Kellogg's 

 pencil has acknowledged on the back of the sheet. It represents the type of Dr. Torrey's 

 Qtierais oblongifolia. which was a new Mexican tree, quite identical with Q. undulata 

 grisea, of which it is but an entire-leaved state. The form is very common on the 

 New Mexican hills, and has nothing else to distinguish it from the tooth-leaved state 

 which is the more prevalent. I scarcelj' need add, that what is true of so very many of 

 our western evergreen oaks, holds in respect to Q. undulata in most of its forms, i. e., that 

 toothed leaves and entire ones are commonly to be seen on the same tree, often on the 

 same twig. 



