KNOWLTON'S IRONWOOD.
0. Knowltoni, Cov.
Knowlton's ironwood is found nowhere but in a this': grove on the southern slope of the canyon of the Colorado in Arizona, about seventy miles north of Flagstaff. here these trees are numerous, crouching under oaks, their twisted branches ending in drooping twigs, bearing the characteristic pale green hops in autumn, small oval leaves, and the catkin flowers in spring. Such a restricted dis
tribution for a distinct species of trees is unmatched in the annals of botany.