Two new species of Acervus (Pezizales) with a key to species of the genus

Studies on the genus Acervus from China are reviewed briefly. Six of the seven known species of the genus are currently recorded in this country. Acervus beijingense and A. changchunense are described as new based on morphological features and molecular data, and A. flavidus with minor emendation is added to the Chinese fungus flora. Phylogenetic relationships among four of the seven species of the genus are investigated based on the 28S rDNA sequence analysis. Species of the genus formed a single clade with high bootstrap support. The sequences of A. epispartius forma epispartius and that of A. flavidus obtained from materials in different geographical regions together formed a group with 100% bootstrap support. Ascospore size and shape are important criteria in the taxonomy of the genus and are phylogenetically informative. A dichotomous key to all described species of the genus is provided.