The origin and development of pseudocyphellae and the pored epicortex are compared. Pseudocyphellae are pores through the paraplectenchymatous cortex which fill with medullary hyphae. The pored epicortex is a thin, perforated polysaccharide sheet lying over a loosely organized cortical layer. Both structures function in gas exchange and may represent two different phyletic lines.

Both light and scanning electron microscopy have been used to investigate the morphology and development of Speerschneidera euploca (Tuck.) Trevisan. This monotypic genus produces lecanoralean apothecia and Lecanora-type asci; the latter negates the assumed relationship to Teloschistes and the Teloschistaceae. The information on morphology, ecology, development and chemistry indicate that the genus is appropriately placed in the Lecanoraceae close to Lecania. S. euploca is found on calcareous outcrops from Missouri southwest to Texas and Mexico. It produces only a brown pigment concentrated in the tips of the paraphyses.

The new genus Degelia (Pannariaceae) is described to accommodate three primarily Southern Hemisphere taxa: D. gayana (Mont.) comb, nov., D. duplomarginata (P. James & Henssen) comb, nov., and D. durietzii sp. nov. A key to the species is given, with data on synonymy, morphology, anatomy, chemistry, habitat and distribution. Coccocarpia gayana var. melacarpina Nyl. is reduced to synonymy with Degelia gayana. Relationships of Degelia with genera in the Pannariaceae and Coccocarpiaceae are discussed. Degelia is distinguished from other genera in the Pannariaceae by periclinal arrangement of cells in the upper cortex, a lower cortex of 2–3 layers of thick-walled periclinal hyphae, and Scytonema as the phycobiont; and from genera in the Coccocarpiaceae by the structure and ontogeny of the apothecia. D. duplomarginata is known from New Zealand and Hawaii, D. durietzii from New Zealand and Tasmania and D. gayana from New Zealand, Tasmania, Australia, Chile and Tristan da Cunha.

A second fascicle of a lichen exsiccata containing species of Caliciales has been issued; 25 species from Europe and North America are included. Some remarks on their taxonomy, nomenclature and distribution are given here. Calicium queenslandiae (F. Wilson) Tibell, Chaenothecopsis nana Tibell, Chaenothecopsis vainioana (Nádv.) Tibell and Phaeocalicium polyporaeum (Nyl.) Tibell are discussed in some detail. Distributional records of interest are given for Calicium queenslandiae, Chaenothecopsis nana, C. subpusilla (Vainio) Tibell, C. vainoiana, C. viridialba (Krempelh.) A. Schmidt and Phaeocalicium polyporaeum.

The phycobionts of 20 different lichens were studied in culture, described and assigned to species of Pseudotrebouxia and Trebouxia. Identical phycobiont species were isolated from widely different lichens which showed that these algal symbionts were not specific to particular mycobionts. There was much variation in cellular detail within individual algal species indicating that the criteria currently used to separate species of these phycobionts may be too restrictive.

Lichen thallus fragments were maintained in a growth cabinet under four differing conditions of light intensity. Levels of usnic acid and atranorin did not differ significantly from the control under any of the treatments. However, perlatolic acid and fumarprotocetraric acid per unit dry weight of thallus were dependent upon light availability.