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 (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==