A new North American species of Hyperphyscia (Physciaceae)

In North America, the widespread sorediate lichen known as Hyperphyscia adglutinata is shown to be heterogeneous. It contains two distinct species, one with primarily laminal soralia and another with marginal soralia. The latter taxon is here described as the new species H. confusa. Hyperphyscia adglutinata and H. confusa have broadly overlapping distributions in North America, especially in the Midwest and Great Plains states. Where they are sympatric, H. confusa is generally the more common of the two. Descriptions and discussions for H. adglutinata and the two other sorediate North American species, H. minor and H. pyrithrocardia, are also included, along with a key for separation of the four species. Hyperphyscia pyrithrocardia is reported for the first time from North America.