Rosa woodsii subsp. Puberulenta and variety ertterae (Rosaceae), New in Western North America

摘要

An additional subspecies and two new varieties of Rosa woodsii Lindl. (Rosaceae) are recognized in western North America. Rosa woodsii subsp. Puberulenta (Rydb.) W. H. Lewis & Ertter, characterized by an open habit and moderately curved prickles, is the predominant bottomland subspecies occurring in the Colorado Plateau of Colorado, Utah, Arizona, Nevada, New Mexico, and Wyoming. Atypical unarmed populations of R. woodsii subsp. Arizonica (Rydb.) W. H. Lewis & Ertter endemic to Oak Creek Canyon in the Mogollon Rim region of Coconino County, Arizona, are described as R. woodsii var. ertterae W. H. Lewis. The new combination R. woodsii var. arizonica (Rydb.) W. H. Lewis is provided for the remainder of R, woodsii subsp. Arizonica. A key to the six subspecies of R. woodsii is provided.