Strigulales
The Strigulales are an order of lichen-forming fungi in the class Dothideomycetes. It contains two families: Strigulaceae and Tenuitholiascaceae, with a combined total of 115 species. The order was proposed in 2013. Most species in the order are foliicolous, that is, they grow on plant leaves.
Taxonomy
Strigulales was introduced as a new order by Robert Lücking, Matthew Nelsen and Kevin Hyde in a 2013 revision of Dothideomycetes classification. The order is distinguished from most Trypetheliales by several microscopic features: its spores have true walls at each division with only a few cross-walls, and secondary metabolites are nearly absent from the lichen tissues. It also differs from both Monoblastiales and Trypetheliales in the structure of its sterile filaments, which are mostly unbranched, and in its large asexual spores, which form gel-like appendages at their ends. The order is typified by the genus Strigula Fr.In 2020, Shu-Hua Jiang, Robert Lücking and Jiang-Chun Wei introduced a new monotypic family, Tenuitholiascaceae, to accommodate Tenuitholiascus porinoides, a foliicolous lichen from Hainan, and placed it within Strigulales. Their molecular analyses recovered Tenuitholiascus as a distinct lineage in the Dothideomycetes forming a sister relationship to Strigulaceae, supporting recognition at family rank within the order; subsequent outlines have retained this placement. The genus is diagnosed by its unusually thin-walled ascus apex and colourless, three-septate spores, features that, together with the phylogeny, justified establishing a separate family in Strigulales.