Studies on the Amphisphaeriales 1. Amphisphaeriaceae (sensu stricto) and its phylogenetic relationships inferred from 5.88 rDNA and ITS2 sequences

Abstract

The Amphisphaeriaceae (sensu lato) presently includes 36 genera and 23 synonyms and is placed in the Xylariales. It is a relatively large and complicated family of ascomycetes. Molecular studies based on DNA sequence data of the 5.8S rRNA gene and internal transcribed spacer ITS2 of seventeen amphisphaeriaceous or related taxa are reported. A phylogenetic tree, using Penicillium marneffei as an outgroup, was derived from 435 sites which have been aligned. Based on the topology of the dendrogram and teleomorph-anamorph connections, the family Amphisphaeriaceae (sensu stricto) are restricted to Amphisphaeria, Discostroma, Ellurema, Lepteutypa, Pestalosphaeria and other genera possessing Pestalotia-like anamorphs. The Clypeosphaeriaceae are retained to include Apioclypea, Capsulospora, Clypeosphaeria, Oxydothis and other related genera. Atrotorquata which segregates from the Amphisphaeriaceae in the phylogenetic tree and morphologically resembles Cainia in having ascus apparatus comprising a series of rings and brown bicelled ascospores with longitudinal germ slits is placed in the Cainiaceae which are revived. Xylaria and Hypoxylon (Xylariales) are from another lineage which are well separated from the Amphisphaeriaceae (sensu stricto), Clypeosphaeriaceae and Cainiaceae. It is not appropriate to place these families in the Xylariales. The Order Amphisphaeriales are therefore revived to accommodate these families.