Studies in the 2000s showed that several species from Asian collection sites labelled under the specific epithet hygrometricus was actually considerably variable in a number of macroscopic and microscopic characteristics . Molecular studies of the DNA sequences of the ITS region of the ribosomal DNA from a number of Astraeus specimens from around the world have helped to clarify phylogenetic relationships within the genus . Based on these results , two Asian " hygrometricus " populations have been described as new species : A. asiaticus and A. odoratus ( synonymous with Petcharat 's A. thailandicus described in 2003 ) . Preliminary DNA analyse suggest that the European A. hygrometricus described by Persoon is a different species than the North American version described by Morgan , and that the European population may be divided into two distinct phylotypes , from France and from the Mediterranean . A 2010 study identified a Japanese species , previously identified as A. hygrometricus , as genetically distinct ; it have yet to be officially named .