Extinct family of plants
From Wikipedia, the free encyclopedia
Williamsoniaceae is a family within the Bennettitales, an extinct group of seed 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 of Pterophyllum 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 from Cycadeoidaceae by having the presence of cones leaving the major axis and lateral branches associated with a long peduncle covered by bracts. Some of this family reproduce by sporangia and others only produce ovule or pollen 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.
