The similar wood, similar cones or epimatium, the similar leaves, the similar pollen. Why are not Glossopteridales, Umkomasiales, Pentaxylales or Cyatoniales included in Araucariales, Cordaitales and Ginkgoales?
Traditionally all of those Mesozoic 'seed fern' groups have been interpreted to bear their seeds on modified foliar organs (cupules), whereas the seeds of conifers are traditionally interpreted to have been borne on axillary shoot complexes (the ovuliferous scale of conifer cones). However, the homologies of the various seed-bearing organs remain rather ambiguous and you may be correct in that conifers and Mesozoic seed ferns share more characters than we currently assume. Perhaps a closer match (in terms of foliar architecture, ovuliferous organs and pollen types) than conifers for Mesozoic seed ferns would be Ginkgoales. This is an issue that several groups of researchers are currently working on.
No, Pentaxylales is totally different group, with a very typical or very specialized morphological as well as anatomical characters, which are not found in any group of fossil plants. It is also sometimes called or referred as 'Synthetic Group'.While other groups as you have mentioned, cannot too be clubbed into each other as each and every group has/have their characters of their own, which seperates them from each other. Birbal Sahni Institute of Palaeosciences, Lucknow, India;is the most apt, best and premier center with the largest data base (best library, best museum) in the world. I am very confident that your problem can be resolved at BSIP.
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