The genus Pyrenomyxa and its affinities to other cleistocarpous Hypoxyloideae as inferred from morphological and chemical traits

Abstract

Types and authentic specimens of Hypoxylon piceum, Pulveria porrecta, and Pyrenomyxa invocans were studied for morphological traits and extrolite (= secondary metabolite) profiles generated by analytical HPLC with UV-visual and mass spectrometric detection. The orange stromatal pigments of P. invocans are rubiginosin A and mitorubrinol. It lacks three different types of extrolites (BNT, macrocarpone and hypomiltin) that are known from Hypoxylon taxa and occur in H. piceum and P. porrecta. In agreement with morphological traits, the latter two names are regarded as synonymous and transferred to Pyrenomyxa. Another species from Eastern Russia, Pyrenomyxa morganii sp. nov., is recognized. It contains yet unidentified azaphilones besides BNT and orsellinic acid, and its culture produces 5-methylmellein and a virgariella-like anamorph. These findings suggest a close relationship of Pyrenomyxa to Hypoxylon and emphasize the utility of chemotaxonomic traits for fungal taxonomy in general. Pyrenomyxa is accepted ad interim until the phylogenetic relationships among Hypoxylon have been further evaluated by means of chemotaxonomic, morphological and molecular methods.

• Xylariales
• Xylariaceae
• chemotaxonomy
• systematics
• extrolite

We are grateful to the curators of the herbaria K (Begoña Aguirre-Hudson), IAS (Deborah Harris), NY (Ellen Bloch) and their colleagues, and to our colleague Jack D. Rogers (Pullman, Wa.) who kindly sent us specimens. Furthermore, we thank Stephan Seip (BHC, Wuppertal) for recording HPLC-MS, Klaus Ide (Bayer Technology Services, Leverkusen, Germany) for his help with SEM, and Dang Ngoc Quang and Yoshinori Asakawa (Tokushima Bunri University, Tokushima, Japan) for providing standard compounds and for confirming the identity of 5-methylmellein. The foundations controlled by the Danish Botanical Society are thanked for financially aiding the fieldwork by TL, and so is Victor Muhkin.