Ostrya knowltonii is a species of
tree known by the common names
Knowlton's hophornbeam,
western hophornbeam,
woolly hophornbeam, and
wolf hophornbeam. It is also one of many trees called
ironwood. It is native to
Utah,
Arizona,
New Mexico, and
Texas in the
United States, but its distribution is localized and sporadic.