[Yu-Ming Ju] Taxonomic revision and phylogenetic analysis of Xylaria in French Guiana, including 38 new species and one new combination
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Figure. Stromatal diversity of Xylaria species from French Guiana. A. Xylaria candelabroides. B. X. depressa. C. X. nigrosticta. D. X. corriolii. E. X. turbiniformis. F. X. palifera. G X. guianica. All species shown are newly described in this study.
Xylaria is a species-rich genus of wood-inhabiting fungi in tropical forests. French Guiana was among the earliest regions in the tropical Americas where Xylaria species were studied, yet the diversity of the genus there had not received a modern integrative treatment for nearly two centuries. This study combines extensive field collections, re-examination of historical material, detailed morphological comparisons, and multilocus phylogenetic analyses based on RPB2, beta-tubulin, and alpha-actin sequences. A total of 98 Xylaria taxa are documented from French Guiana, with two additional related species from Brazil and the French West Indies included for comparison. Thirty-nine taxa are recognized as novel to science, comprising 38 newly described species and one new combination. Thirty-seven of the 38 new species were included in the phylogenetic analyses, which further support their distinctiveness. The study also reassesses numerous names reported from French Guiana in the nineteenth century through type studies and critical morphological evaluation and reveals substantial cryptic diversity within the X. scruposa and X. cantareirensis species complexes. The results demonstrate that French Guiana harbors a much richer and more complex Xylaria diversity than previously recognized and provide an integrative taxonomic framework for future studies of tropical fungal diversity and biogeography.