†order Trigonocarpales (cycads)
Synonym: Medullosales [replaced name]
Parent taxon: Cycadopsida according to S. V. Meyen 1984
See also Taylor et al. 2008
Sister taxa: Boweniaceae, Crassofilicites, Cycadales, Deltolepis, Dioales, Drepanozamites, Gnetales, Lagenostomales, Manebachia, Marantoidea, Orthogoniopteris, Pteridospermales, Stangeriaceae, Strangerites, Welwitschiales
Subtaxa: Alethopteridaceae Angiospermophyton Sarcospermum Trigonocarpaceae Trigonocarpolithus
Distribution:
• Triassic of Hungary (1 collection)
• Permian of Canada (1: Nunavut), China (55), Mexico (1), Mongolia (2), the Russian Federation (21), Saudi Arabia (1), Spain (1), Turkey (1)
Total: 84 collections including 114 occurrences