Bennettitales

Bennettitales Temporal range: Triassic to Cretaceous
A Cycadeoid, showing an "inflorescence" in the top-right
Scientific classification
Kingdom:	Plantae
Division:	Spermatophyta
Class:	Spermatopsida
Order:	Bennettitales †
Families
Cycadeoidaceae Williamsoniaceae

Bennettitales (the cycadeoids) is an extinct order of seed plants that first appeared in the Triassic period and became extinct toward the end of the Cretaceous. Some were characterized by thick trunks and pinnately compound leaves that bore a superficial resemblance to those of cycads, differing primarily in stomatal arrangement.

It comprises two groups, the Cycadeoidaceae, represented by Cycadeoidea, Cycadella, and Monanthesia which had stout trunks and bisporangiate strobili (cones serving as their reproductive structures), and the Williamsoniaceae including Williamsonia, Williamsoniella, Wielandella and Ischnophyton which had slender, branching trunks and either bisporangiate or monosporangiate strobili. Bennettitales have been placed among the anthophytes, which for some time were considered to be close relatives of the flowering plants on account of their flower-like structures. However, more detailed morphological studies have shown the "anthophytes" to be polyphyletic, with the bennetitales more closely related to the cycads, ginkgo and conifers than to the angiosperms.

Gallery

• 
  A fossilised Bennettitales, squashed by later compression.
• 
  Side view. Note embedded "flowers".
• 
  A flower-like structure.
• 
  Fossil leaf of Zamites mariposana from the Jurassic.

External links

• Gymnosperms
• Lecture Notes on Mesozoic Mesophytic Communities