References in periodicals archive ?
Class 3 Polypodiopsida (Filicinophyta, Pterophyta, Pterodatina, Pteridophyta, Psilophytes, Psilopsids, Ferns, Whisk Fern)
Shales of the Late Devonian Grassy Creek Formation exposed by these excavations yielded an abundance of compressions of primitive plants including what are believed to be psilophytes, primitive leafless land plants.