Sporodictyon

Sporodictyon is a genus of crustose lichens in the family Verrucariaceae. It has 10 species. Most species grow on rocks, although some have been recorded overgrowing soil and mosses.

==Taxonomy== The genus was circumscribed in 1852 by Italian lichenologist Abramo Bartolommeo Massalongo, with Sporodictyon schaererianum assigned as the type species. Until fairly recently, the genus was usually included in Polyblastia, which is a conserved name. As a result of molecular phylogenetic work published in 2008, the genus was resurrected by Sanja Savić and Leif Tibell for three species that formed a monophyletic clade, and which included the type species: S. cruentum, S. schaererianum, and S. terrestre. Several molecular phylogenetic-based publications have shown that characters traditionally used to separate taxa in the Verrucariaceae, namely spore septation and growth form, are not always reliable for representing monophyletic groups at generic and higher ranks. Historically, descriptions of Sprodictyon species have relied heavily on the following characters: thallus development, size of perithecia, structure of the involucrellum (the upper, often exposed covering external to the excipulum), and the size and colour of ascospores. However, the morphological variability of species, and sometimes ambiguous generic concepts means that the taxonomy of this group of species has been difficult. Following the molecular work, Savić and Tibell found that ascoma size, spore pigmentation, spore size, and thallus structure are the most useful features for species recognition in Sporodictyon.