APPEKDIX m. 
Saint Louis, December 31, 1860. 
Dear Sir: Want of time has prevented me fully to elaborate the very rich 
botanical material brought together, under your orders, by my brother, Henry Engel-’ 
mann, the geologist and meteorologist of your expedition. 
I herewith inclose to you an account of a few species, which seem to have a par¬ 
ticular, and principally a practical, interest. 
I expect to continue my investigations, and ht>pe to submit them, through you, to 
the scientific public at a future period. 
Very respectfuly, &c., 
George Engelmann. 
Oapt. J. H. Simpson, 
Topographical Engineers, U. S. A., Commanding Expedition. 
ROSACEA 
Cercocarpus ledifolius, Nuttall in Torrey and Gray j s Fl. JV. Am. 1 ,p. 427; and in 
his continuation of Michauxts Sylva , 2, p. 28, t. 51; Hooker, i. c. pi. 1-324; Mountain- 
Mahogany of the inhabitants of Utah. 
This small evergreen tree is so well described by Nuttall in both works mentioned 
that not much remains to be added. His figure, however, is not a very faithful repre¬ 
sentation. He says that it grows much like a peach-tree, at most 15 feet high, and 
that the trunk is sometimes as much as a foot in diameter. On the expedition, it was 
found to grow rarely as a tree, but usually branching from the base, or several stems 
from one root; its height was from 8-15 feet, and the stems seen had the thickness of 
3-6, or, at most, 10 inches. The bark is light gray, tough, smoothish, with superficial 
longitudinal wrinkles and short transverse scars. The wood is hard, heavy, very close- 
grained, light reddish-brown, with white sap; medullary rays very numerous, but 
extremely fine, scarcely visible with the naked eye; the wood is similar to cherry-wood, 
but harder and heavier. A specimen before me has a diameter of 16 lines, 14 lines of 
which are wood, showing 24 annual rings, so that each ring has a thickness of not 
much more than \ line. The shoots, or longer branches, have a white, smooth bark, 
with joints or internodes of about 1 inch in length. The leaves, however, are usually 
