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Plants with cycad-like form; flower-like reproduction
Plants with cycad-like form; flower-like reproduction
The Bennettitaleans are a seed-bearing, cycad-like group from the Mesozoic Era. They were originally mistaken for cycads because of their growth form, but their reproductive structures and stomatal structure make them more related to flowering plants. There are two groups: the cycadeoids (stout trunks and bisporangiate reproductive structures), and Williamsonia and Williamsoniella (slender, branching trunks and either bisporangiate or monosporangiate strobili). These reproductive structures are quite flower-like: sterile petal-like bracts, with a whorl of microsporophylls, with ovulate receptacle in the center.
Ecology & Form
Ecology & Form
Stems
Stems
Short tree
Woody stems that is heavily armored with persistent leaf bases
Very cycad-like vegetatively; example of convergent evolution
Leaves
Leaves
Pinnate and cycad-like leaves with syndetocheilic stomata (Form genus is Nilssonia)
Oleanane present (similar to angiosperms)
Roots
Roots
Unknown
Reproductive Structures
Reproductive Structures
Bisexual seed-cones that are flower-like
Outermost sterile bracts similar to sepal-like structures
Possible colorful petal-like structures
May have attracted and been pollinated by early invertebrates
Microsporophylls are pinnate fronds with pollen sacs
Ovulate structure
Ovules alternate with scales on ovulate receptacle
Reminiscent of angiosperm carpal (may be too derived to be ancestral to angiosperms)
Ovules
Reduced gametophyte
Rapid fertilization and embryogenesis after pollination
Classification
Classification
Geologic Age
Geologic Age
Early Permian (Cisuralian) - Late Cretaceous
Additional Resources
Additional Resources
Harvesting the Extinct Bennettitales (Deposits Magazine, 2016)
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