Pityopus californicus is a rare mycoheterotrophic herb that occurs in coniferous and mixed forests of western North America. Previous authors have speculated that Pityopus californicus is not a true species but is a recurring hybrid. The reputed parental candidates of P. californicus include the closely related Pleuricospora fimbriolata, Hemitomes congestum, and Monotropa hypopithys. However, a phylogenetic analysis of large ribosomal subunit (26S) rRNA gene sequences suggests that Pityopus californicus is sister to Monotropa hypopithys and not a recurring hybrid.
"Systematic relationships of Pityopus californicus inferred from large ribosomal subunit (26S) rRNA gene sequences,"
Western North American Naturalist: Vol. 65
, Article 11.
Available at: http://scholarsarchive.byu.edu/wnan/vol65/iss4/11