Bennettitales - Williamsoniaceae
Parent taxon: Bennettitales according to S. V. Meyen 1984
See also Taylor et al. 2008
Sister taxa: Amarjolia, Anomozamites, Bennetticarpus, Bennettistemon, Bennettitaceae, Bennettitaepollenites, Bennettiteaepollenites, Bennettitolepis, Bysmatospermum, Coreanophyllum, Cycadeospermum, Cycadolepis, Dictyozamites, Guptioxylon, Leguminanthus, Lerouxia, Moltenia, Monanthesia, Nilssoniopteris, Ontheanthus, Ontheostrobus, Otozamites, Palaeanthus, Piroconites, Pseudocycas, Pterophyllum, Ptilophyllum, Purioxylon, Rajmahalia, Sahnioxylon, Sturiella, Tyrmia, Tysonia, Vardekloeftia, Weltrichia, Wielandiella, Williamsonia, Williamsonianthus, Williamsoniella, Wonnacottia, Zamites
Subtaxa: Lyssoxylon
Distribution: found only at Fort Wingate (Triassic of New Mexico)