Complex sentence: A recent study has conservatively estimated global ectomycorrhizal fungal species richness at approximately 7750 species, although, on the basis of estimates of knowns and unknowns in macromycete diversity, a final estimate of ECM species richness would probably be between 20000 and 25000.
Split into simpler sentences: A recent study has conservatively estimated global ectomycorrhizal fungal species richness at approximately 7750 species. Although, on the basis of estimates of knowns and unknowns in macromycete diversity, a final estimate of ECM species richness would likely be between 20000 and 25000.