EXPLORATIONS AND SURVEYS FOR A RAILROAD ROUTE FROM THE MISSISSIPPI RIVER TO THE PACIFIC OCEAN. 
WAR DEPARTMENT. 
REPORT 
ON THE 
BOTANY OF THE EXPEDITION: 
JOHN TORREY AND ASA GRAY. 
ROUTE NEAR THE THIRTY-SECOND PARALLEL OF NORTH LATITUDE, UNDER THE COMMAND OF BREVET 
CAPTAIN JOHN POPE, CORPS OF TOPOGRAPHICAL ENGINEERS. 
