Уильямсония: вымерший род растений юрского периода.

the dragonfly
Extinct genus of plant
Automatic taxobox
| fossil range =
| image = Williamsonia harrisiana seed cone cross section. svg
| image caption = Cross section of Williamsonia harrisiana (India, Jurassic Early Cretaceous)
| taxon = Williamsonia (plant)
| authority = Carruth., 1870
| range map =
| range map caption =
| type species = Williamsonia gigas
| type species authority = Carruth., 1870

The monosporangiate) consists of an ovulate receptacle enclosed by bracts (modified leaves), with the receptacle bearing sporophylls with terminal seeds/ovules, which are surrounded by interseminal scales. The micropyle of the ovules varied from protruding above the cone to slightly sunken in, depending on the species. The cone was borne on a peduncle, and grew at the apex of a branch. Kimuriella is thought to have been a divaricately branching, low growing shrub with a maximum height of 2–3 metres, with a growth form similar to that of Wielandiella, while Williamsonia gigas may have been more cycad like. In Kimuriella and W. gigas, the axes (assigned to Bucklandia in W. gigas), which were up to and wide respectively, were densely covered with persistent leaf bases, which were apparently sloughed off in older branches. to the family Williamsoniaceae has been questioned, with some scholars suggesting that the species may represent an early species of Cycadeoidaceae instead.

Williamsonia was originally described as Zamia gigas by William Crawford Williamson. William Carruthers proposed the name Williamsonia in 1870, with the type species being W. gigas from the Middle Jurassic of England. and have been found worldwide, including in Europe, Australia, and South America.