References from the California Lichen Catalog

THOMSON, J. W. 1987.

The lichen genera Catapyrenium and Placidiopsis in North America. The Bryologist 90: 27–39.

TUCKERMAN, E. 1872.

Genera Lichenum. An arrangement of the North American lichens. Edwin Nelson, Amherst. 281 pp. + index.

WILLEY, H. 1873a.

A list of North American lichens arranged according to Professor E. Tuckerman's “Genera Lichenum”. New Bedford.