Walchian conifers and pteridosperms are common elements in the macroflora, but are absent in the sporomorph assemblages.
Cindy V. Looy, Robert A. Stevenson, Thomas B. Van Hoof, Luke Mander 2014, 'Evidence for coal forest refugia in the seasonally dry Pennsylvanian tropical lowlandsof the Illinois Basin, USA', PeerJhttps://peerj.com/articles/630.pdf. Retrieved from DOAJ CC BY 4.0 (https://creativecommons.org/licenses/by-sa/4.0/legalcode)