Resurrection and emendation of the Hypoxylaceae, recognised from a multigene phylogeny of the Xylariales

Abstract

A multigene phylogeny was constructed, including a significant number of representative species of the main lineages in the Xylariaceae and four DNA loci the internal transcribed spacer region (ITS), the large subunit (LSU) of the nuclear rDNA, the second largest subunit of the RNA polymerase II (RPB2), and beta-tubulin (TUB2). Specimens were selected based on more than a decade of intensive morphological and chemotaxonomic work, and cautious taxon sampling was performed to cover the major lineages of the Xylariaceae; however, with emphasis on hypoxyloid species. The comprehensive phylogenetic analysis revealed a clear-cut segregation of the Xylariaceae into several major clades, which was well in accordance with previously established morphological and chemotaxonomic concepts. One of these clades contained Annulohypoxylon, Hypoxylon, Daldinia, and other related genera that have stromatal pigments and a nodulisporium-like anamorph. They are accommodated in the family Hypoxylaceae, which is resurrected and emended. Representatives of genera with a nodulisporium-like anamorph and bipartite stromata, lacking stromatal pigments (i.e. Biscogniauxia, Camillea, and Obolarina) appeared in a clade basal to the xylarioid taxa. As they clustered with Graphostroma platystomum, they are accommodated in the Graphostromataceae. The new genus Jackrogersella with J. multiformis as type species is segregated from Annulohypoxylon. The genus Pyrenopolyporus is resurrected for Hypoxylon polyporus and allied species. The genus Daldinia and its allies Entonaema, Rhopalostroma, Ruwenzoria, and Thamnomyces appeared in two separate subclades, which may warrant further splitting of Daldinia in the future, and even Hypoxylon was divided in several clades. However, more species of these genera need to be studied before a conclusive taxonomic rearrangement can be envisaged. Epitypes were designated for several important species in which living cultures and molecular data are available, in order to stabilise the taxonomy of the Xylariales.

Can we use environmental DNA as holotypes?

“…Species in this genus constitute a rich source of bioactive secondary metabolites (Song et al 2014). Recently the phylogeny of the family was changed, following multilocus DNA pyhlogenies and some comprehensive reviews of their taxonomy have been provided by Daranagama et al (2018) and Wendt et al (2018). Helaly et al (2018) concluded that future culturing and phylogenetic studies are needed to reach a better taxonomic classification of Xylaria.…”

Conidial fungi associated with leaf litter of red cedar (Cedrela odorata) in Belém, Pará (eastern Brazilian Amazon)

“…ex Lindau. This genus is included in the Graphostromataceae (Xylariales) and is characterized by the presence of macronematous conidiophores, usually forming a vesicle clavate at the apex, where cicatrized, sympodial conidiogenous cells produce unicellular, hyaline conidia with rhexolytic secession (Seifert et al 2011;Wendt et al 2018). Xylocladium claviforme was first described as Masoniomyces claviformis J.L.…”

A novel species and a new combination of Daldinia from Ban Hua Thung community forest in the northern part of Thailand

“…The genus Daldinia was described by Cesati and De Notaris (1863) and belongs to the Hypoxylaceae (Xylariales), since the recent rearrangement of the families of stromatic Xylariales by Wendt et al (2018). The Hypoxylaceae is one of the largest families in this order and both the family and the genus Daldinia have been studied exhaustively for secondary metabolite production (Helaly et al 2018).…”