LITERATURE CITED
- Culberson, C. F. 1969. Chemical and botanical guide to the lichen products. University of North Carolina Press, Chapel Hill. (In press.)
- Culberson, W. L. 1967. Analysis of the chemical and morphological variation in the Ramalina siliquosa species complex. Brittonia 19: 333–352.
- Culberson, W. L., and C. F. Culberson. 1967. Habitat selection by chemically differentiated races of lichens. Science 158: 1195–1197.
- Hale, M. E., Jr. 1967. The biology of lichens. Edward Arnold Ltd., London. 176 p.
- Hale, M. E., Jr., and W. L. Culberson. 1966. A third checklist of the lichens of the continental United States and Canada. Bryologist 69: 141–182.
- Schade, A. 1954. Über Letharia vulpina (L.) Vain, und ihre Vorkommen in der Alten Welt. Ber. Bayerischen Bot. Gesell. 30: 109–126.
- Schade, A.. 1955. Letharia vulpina (L.) Vain.—II. Ihr Vorkommen in der Neuen Welt und ihr Verhältnis zu Letharia californica (Lév.) Hue em. DR. Feddes Repert. Spec. Nov. 58: 179–197.
- Thomson. J. W. 1966. The relationship of Bacomyces fuscorufescens Vainio and B. carncus (Retz.) Floerke. Mem. Soc. Fauna Flora Fenn. 42: 49–53.
- Zopi, W. 1907. Die Flechtenstoffe in chemischer, botanischer, pharmakologischer und technischer Beziehung. Gustav Fischer, Jena. 450 p.