The Use of Anisaldehyde Sulfuric Acid as an Alternative Spray Reagent in TLC Analysis Reveals Three Classes of Compounds in the Genus Usnea Adans. (Parmeliaceae, lichenized Ascomycota)

Presence and identity of secondary metabolites are two of the main components of lichen taxonomy. Aromatic compounds formed via the acetyl-polymalonate pathway are the most studied lichen substances. In addition, compounds derived from the mevalonic acid pathway (e.g., terpenes and steroids) are sometimes detected in the medulla. However, their identity and value as diagnostic characters in the genus Usnea are yet poorly understood despite the fact that they were mentioned in several taxonomical papers. We conclude that i) aside from the previously recognized polyphenolic compounds, carbohydrates and steroids are also detected in the medulla of some Usnea species; ii) the use of sulfuric anisaldehyde reagent greatly improves the detection of terpenes, carbohydrates and steroids compared with the sulfuric acid reagent routinely used in thin layer chromatography; iii) among carbohydrates, we detected arabitol and sucrose in the medulla; iv) steroids and terpenes remain unidentified and deserve further investigations.

Olof Swartz's contributions to lichenology, 1781–1811

The Swedish botanist Olof Peter Swartz (1760–1818), a student of Carl Peter Thunberg and Carl Linnaeus the Younger at Uppsala University, developed an interest in mosses and lichens, which he made the subject of his medical dissertation. He visited Jamaica (1783–1786) where he collected all plant groups and a substantial number of lichens. Apart from the lichens that Swartz described himself, his lichen collections from Sweden, the eastern United States and Jamaica were critically examined by Erik Acharius who described many species from his material. Swartz was a key supporter of Acharius's work on the development of a new system of lichen taxonomy between 1794 and 1814. Although he is largely known for his pioneering work on flowering plants (especially orchids) and ferns, Swartz made important contributions to late eighteenth- and early nineteenth-century lichenology, publishing five major accounts describing 37 new species. Of these, 27 names are basionyms of accepted taxa.

Ascoma Ontogeny: is this Character Set of any Use in the Systematics of Lichenized Ascomycetes?

The use of ascoma ontogeny in the systematics of lichenized ascomycetes is reviewed briefly. Two recently studied examples are discussed to illustrate the use of ontogenetic studies to discover phylogenetic relationships. As one example, the Agyriaceae was mainly circumscribed by the ascus type and included diverse genera. Xylographa is characterized by lirelliform apothecia. However, the ascoma development shares the ontogenetic pattern observed in Trapelia and its placement in the family was confirmed. In contrast, Anamylopsora exhibited a substantially different apothecial development and was separated as a family of its own. As a second example, the Candelariaceae is based on chemical characters. With the detection of pulvinic acid derivatives also in the genus Lecanora, the distinction of the Candelariaceae and Lecanoraceae became doubtful. Therefore, the ascoma ontogeny was employed to evaluate this classification and is illustrated here in detail for Candelaria fibrosa. The substantial similarity of the ascoma development found in both families suggests that both might be better united. Finally, a general discussion of the significance of ontogenetic characters in lichen taxonomy is included.