Plate XXIII. Pinus Apacheca showing crown form in open stand, 40 feet high and 20 inches in diameter.

Illustration by A.E. Hoyle (signed lwer left), in:

Sudworth, George B. The Pine Trees of the Rocky Mountain Region (Washington, D.C.: Government Printing Office, 1917) USDA Bulletin No. 460.

U.S. Forest Service Headquarters History Collection.