Molecular Phylogeny and Morphology Reveal Cryptic Species in the Cordyceps militaris Complex from Vietnam

The Cordyceps militaris complex, which is a special group in the genus Cordyceps, is rich in species diversity and is widely distributed in nature. Throughout the investigations of arthropod-pathogenic fungi in the national reserves and in Vietnam parks, collections of C. militaris attacking lepidopteran pupae or larvae were located in the soil and on the leaf litter. The phylogenetic analyses of the combined nrSSU, nrLSU, TEF, RPB1, and RPB2 sequence data indicated that the fungal materials collected in Vietnam belonged to C. militaris and two hidden species in the C. militaris complex. The phylogenetic analyses and morphological comparisons presented here strongly supported the descriptions of C. polystromata and C. sapaensis as new taxa as well as C. militaris as a known species. The morphological characteristics of 11 species in the C. militaris complex, which included two novel species and nine known taxa, were also compared.