 Scientists do not know why the fungus mysteriously lives only in Texas and Japan , locations of approximately the same latitude , but separated by 11 @,@ 000 km ( 6 @,@ 800 mi ) . Fred Jay Seaver commented " this is only another illustration of the unusual and unpredictable distribution of many species of the fungi . It would be difficult indeed to account for it , and we merely accept the facts as they are . " In 2004 , a research study compared the DNA sequences of both populations and used a combination of molecular phylogenetics and molecular clock calculations to estimate the extent of genetic divergence . It concluded that the two populations have been separated for at least nineteen million years , ruling out the possibility of human introduction of the species from one location to the other . Although there are no consistent differences in morphology between the two populations , there are several differences in their life histories . The preferred host of Texan populations is typically roots and stumps of Ulmus crassifolia , while the Japanese populations tend to grow on the fallen trunks of <unk> <unk> and Quercus <unk> . Texan species grow in areas subjected to periodic flooding , unlike their Japanese counterparts . Finally , only Japanese specimens can be grown in culture — the spores of Texan material have not been successfully germinated on artificial media . 
