Xylaria melitensis (Xylariaceae), a new penzigioid species from the Maltese Islands

Abstract

Based on detailed morphological observations of both sexual and asexual morphs in vivo, cultures in vitro and molecular phylogenetic data based on rDNA ITS and LSU sequences, we document herein a penzigioid Xylaria repeatedly collected in the Maltese islands of Gozo and Malta. Though it morphologically resembles X. sibirica by stromatal habit and ascospores in the same size range with a long sigmoid germ slit, some significant differences could be detected after comparison of this Xylaria with an isotype collection of X. sibirica. Further differences in cultural characteristics and occurrence of a distinctive asexual morph in vivo preceding the development of the sexual morph, along with a molecular phylogenetic analysis clearly showing that they are distantly related, strongly support the recognition of this penzigioid Xylaria as a distinct species with phylogenetic affinities with the X. polymorpha aggregate. We therefore introduce X. melitensis sp. nov. to accommodate it.