**Xylariomycetidae **O.E. Erikss & Winka, Myconet 1: 12 (1997)

*MycoBank number:* MB 501509; *Index Fungorum number:* IF 501509; *Facesoffungi number:* FoF 06514;

Different outlines of Xylariomycetidae have been published by Maharachchikumbura et al. (2016b), Samarakoon et al. (2016b) and Hongsanan et al. (2017). However, in the present study, we have revised the subclass. Concatenated LSU, ITS, *rpb2 *and *tub2 *based maximum likelihood phylogeny resulted in a well-supported backbone tree for 34 families in Xylariomycetidae (Fig. 4). The divergence time for Xylariomycetidae is estimated as 278 MYA (Fig. 2). There are three distinct clades in the tree representing the orders discussed in previous studies: Xylariales, Amphisphaeriales and Delonicicolales. The sister orders Xylariales (15 families) and Amphisphaeriales (17 families) have moderate statistical support (55% ML) and basal to these is the highly supported clade Delonicicolales (100% ML). Samarakoon et al. (2016b) and Hongsanan et al. (2017) provided divergence time estimations as additional information for Amphisphaeriales, which is estimated to have diverged from Xylariales around 152–187 Mya and provides evidence for these as distinct orders. Families accepted in Amphisphaeriales in this paper are similar to Hongsanan et al. (2017). In this study, we accept Cainiaceae as placed in Xylariales (Figs 1, 4), while Iodosphaeriaceae (Figs 1, 4) which was previously referred to the Xylariomycetidae *incertae sedis, *(Hongsanan et al. 2017) is placed in Amphisphaeriales. Xyladictyochaetaceae (Crous et al. 2018b) is accepted in Amphisphaeriales and clusters with Phlogicylindriaceae with high statistical support (95% ML; Fig. 4). Hansfordiaceae (Crous et al. 2019b) is sister to Coniocessiaceae in Xylariales with strong statistical support (82% ML; Fig. 4). Cylindriaceae (Crous et al. 2018b) and Pseudotruncatellaceae (Crous et al. 2019b) are placed in Amphisphaeriales with poor statistical support (Fig. 4). Induratiaceae will be introduced by Samarakoon et al. (2020) and is placed in Xylariales (Fig. 4). Voglmayr et al. (2019a) introduced Leptosilliaceae as a new family which is sister to Delonicicolaceae, while rejecting Delonicicolales. However, with high statistical support (Fig. 4), we accept Delonicicolales in this study. Currently there are three orders and 35 families in this subclass (this paper).

**Figure 1 **– Maximum likelihood (ML) majority rule combined LSU, SSU, *tef1 *and *rpb2 *consensus tree for the analyzed Sordariomycetes isolates. Families are indicated in yellow and green coloured blocks and orders are indicated in dark and light grey coloured blocks. RAxML bootstrap support values (MLB above 50 %) are given at the nodes. The scale bar represents the expected number of changes per site. The tree is rooted with *Botryotinia fuckeliana *(AFTOL ID-59), *Dothidea sambuci *(DAOM 231303), and *Pyxidiophora arvernensis *(AFTOL-ID 2197).

**Figure 1 **– Continued.

**Figure 1 **– Continued.

**Figure 2 **– The maximum clade credibility (MCC) tree, using the same dataset from Fig. 1. This analysis was performed in BEAST v1.10.2. The crown age of Sordariomycetes was set with Normal distribution, mean = 250, SD = 30, with 97.5% of CI = 308.8 MYA, and crown age of Dothideomycetes with Normal distribution mean = 360, SD = 20, with 97.5% of CI = 399 MYA. The substitution models were selected based on jModeltest2.1.1; GTR+I+G for LSU, *rpb2 *and SSU, and TrN+I+G for *tef1 *(the model TrN is not available in BEAUti 1.10.2, thus we used TN93). Lognormal distribution of rates was used during the analyses with uncorrelated relaxed clock model. The Yule process tree prior was used to model the speciation of nodes in the topology with a randomly generated starting tree. The analyses were performed for 100 million generations, with sampling parameters every 10000 generations. The effective sample sizes were checked in Tracer v.1.6 and the acceptable values are higher than 200. The first 20% representing the burn-in phase were discarded and the remaining trees were combined in LogCombiner 1.10.2., summarized data and estimated in TreeAnnotator 1.10.2. Bars correspond to the 95% highest posterior density (HPD) intervals. The scale axis shows divergence times as millions of years ago (MYA).

**Figure 2 **– Continued.

**Figure 2 **– Continued.

**Figure 4 **– Phylogram generated from maximum likelihood analysis based on combined ITS, LSU, *rpb2 *and *tub2 *sequence data for Xylariomycetidae. Two hundred and seventy-two strains are included in the combined analyses which comprised 4211 characters (1168 characters for ITS, 937 characters for LSU, 1128 characters for *rpb2*, 978 characters for *tub2*) after alignment. *Achaetomium macrosporum *(CBS 532.94), *Chaetomium elatum *(CBS 374.66) and *Sordaria fimicola *(CBS 723.96) are outgroup taxa. Single gene analyses were carried out and the topology of each tree had clade stability. The best RaxML tree with a final likelihood value of – 132297.706952 is presented. Estimated base frequencies were as follows: A = 0.241914, C = 0.251908, G = 0.265558, T = 0.240620; substitution rates AC = 1.281946, AG = 3.512297, AT = 1.499895, CG = 1.121065, CT = 6.472834, GT = 1.000000; gamma distribution shape parameter a = 0.678614. Bootstrap support values for ML greater than 75% are given near the nodes. Ex-type strains are in bold. The newly generated sequences are indicated in blue.

**Figure **– **4 **Continued.

**Figure **– **4 **Continued.

**Figure 4 **– Continued.

**Orders**

Xylariomycetidae families incertae sedis

Xylariomycetidae genus incertae sedis