By Asa Gray and Sir Joseph Hooker. From the Bulletin of the United States Survey of the Territories, Vol. VI., No. 1. These distinguished botanists, to whom the world already owes so much, have in this laborious work, again made us all their debtors. The geography of plants is a very fascinating department of natural history. This shows the range of the Rocky Mountain plants in comparison with that of other parts of the world, and is replete with interesting facts in connection with this study. A large number of plants are peculiar to the Rocky Mountain region.