Genus of lichens
Crocynia is a genus of lichen-forming fungi in the family Ramalinaceae. It has five species. The genus is currently in taxonomic limbo because molecular studies have shown that "Crocynia", which has nomenclatural priority over "Phyllopsora", is phylogenetically nested within "Phyllopsora". This has led to a proposal to conserve the name "Phyllopsora" over "Crocynia" to ensure nomenclatural stability and avoid taxonomic disarray.
Taxonomy.
The genus "Crocynia" was initially circumscribed by Erik Acharius in 1810 as a section within the genus "Lecidea", under the name "Lecidea" sect. "Crocynia". It was later elevated to genus rank by Abramo Bartolommeo Massalongo in 1860. The type species of the genus is "Crocynia gossypina", which was originally described as "Lichen gossypinus" by Olof Swartz.
"Phyllopsora" was described by Johannes Müller Argoviensis in 1894 to accommodate several species from New Zealand. Over time, it has become recognised as a pantropical genus, mainly occurring in moist woodlands and rainforests. The genus comprises nearly 60 species, including those indicating the types of three genera that have priority over "Phyllopsora": "Triclinum" (1825), "Symplocia" (1854), and "Crocynia" (1860).
Recent molecular studies have shown that "Crocynia" is phylogenetically nested within the genus "Phyllopsora". This has led to a proposal to conserve the name "Phyllopsora" over "Crocynia" and other competing names to ensure nomenclatural stability. According to the authors of the 2019 proposal, the conservation of "Phyllopsora" against "Crocynia" and "Triclinum" is favoured to avoid taxonomic disarray, given that the type material for many "Crocynia" species has been lost, and the historical inclusion of distantly related species has caused confusion.
"Crocynia gossypina" is a pantropical lichen species characterised by its ;dfn id="" ;byssoid ;/dfn ; (cottony) thallus, which lacks an upper cortex, making it distinctive. However, many species historically placed in "Crocynia" have been reassigned to other genera, such as "Lepraria". The genus name "Phyllopsora" is widely known and used among lichenologists, particularly those working with tropical material, making it a practical choice for conservation.
If the proposal is accepted, the genus "Crocynia" will be synonymised under "Phyllopsora", reflecting current phylogenetic understanding and simplifying the classification of these lichens. This change will also help maintain continuity in the scientific literature and avoid the need for extensive renaming of species.
Species.
As of June 2024[ [update]], Species Fungorum (via the Catalogue of Life) accept five species of "Crocynia":
References.
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