For more than a decade, two mycologists on opposite ends of the world have collaborated on studies of a large and diverse group of fungi known as pyrenomycetes.

Their research has yielded several genera (the plural of genus) and more than 25 species of pyrenomycetes new to science. Two of these new species – Diatrype caryae and Diatrype ilicina (shown in the image above) – were collected in Arkansas by Larissa Vasilyeva, a mycologist at the Institute of Biology and Soil Science of the Far Eastern Branch of the Russian Academy of Sciences.

These fungi are common and also among the most important of the fungi that decompose wood, said Steve Stephenson, a research professor in the Department of Biological Sciences at the University of Arkansas.

Steve Stephenson in his lab at the University of Arkansas. | Matt Reynolds, University of Arkansas

Steve Stephenson in his lab at the University of Arkansas. | University of Arkansas

“However, they are not particularly well-known or conspicuous,” Stephenson said. “Many of them produce fruiting bodies that are dark brown to black in color and thus are not readily apparent unless one looks in some of the places, such as the lower surface of a decomposing log in contact with the ground, where they are most likely to be found.”

Stephenson and Vasilyeva, one of the world’s leading authorities on pyrenomycetes, have been examining the evidence for a pattern of distribution, known as the “Asa Gray disjunction,” in these organisms.

Asa Gray was a 19th century American plant taxonomist who pointed out that a number of closely related plants found in eastern North America also occur in eastern Asia – but they are not found anywhere other than these two widely separated regions of the world.

Diatrype caryae | Courtesy Larissa Vasilyeva

Diatrype caryae | Courtesy Larissa Vasilyeva

“This pattern has been well documented for plants and appears to be not uncommon for fungi, although relatively little definitive data exist for the latter group,” Stephenson said.

In more than 20 published papers from 2004 to the present, Vasilyeva, who is based in Vladivostok, and Stephenson, previously in West Virginia and now Arkansas for most of his career, have reported numerous examples of pyrenomycetes that display the “Asa Gray disjunction” pattern of distribution.