Williamsoniaceae is a family within theBennettitales, anextinct group ofseed plants. Members of this family are believed to have been around two meters tall and with widely serrate leaves along a central stem. Reproductive organs of the Williamsoniaceae have varied widely in the fossil record but almost all have been found to be borne on stalks emerging from a ring of leaves.[1]
Fossils and schematic diagram ofPterophyllum bavieri from the Late Triassic (Rhaetian) of northern Iran,Shemshak Group, A and B: leaves attached to a branch C: complete leaf
This family is different fromCycadeoidaceae by having the presence ofcones leaving the major axis and lateral branches associated with a longpeduncle covered bybracts. Some of this family reproduce bysporangia and others only produceovule orpollen sacs.[2]
^Meyen, Sergei V. (1984). "Basic Features of Gymnosperm Systematics and Phylogeny as Evidenced by the Fossil Record".Botanical Review.50 (1):1–111.doi:10.1007/BF02874305.JSTOR4354028.S2CID38485693.
