Sporne (1965) discussed Palaeocycas as the only fossil genus belonging to Cycadaceae. Florin (1933) described the female sporangiophores of this genus belonging to Palaeocycas integer and its leaves belonging to Bjuvia simplex. The female sporangiophores of Palaeocycas integer were described from Upper Triassic rocks of Sweden.
These sporangiophores are believed to have borne seeds. Its leaves resembled that of present day banana plants and reached up to 1 metre in length and 20 cm in breadth (Fig. 8.6A). The female sporangiophores were comparatively much smaller reaching only up to 13 cm in length and about 5 cm in breadth (Fig. 8.6B).
The leaves of this plant were arranged in the form of a crown at the top of a strong stem according to Florin. Female sporangiophores had seeds and were loosely aggregated in the centre of the crown of leaves. The plants looked like that of the present day Cycas plants. However, the trunk of this plant has not been reported, and, therefore, the description of the plant given by earlier workers appears hypothetical.
There, however, exist close similarities between the shape of epidermal cells, guard cells and subsidiary cells of both Palaeocycas and Bjuvia which is an indication that they both belong to only one cycad.
Sporne (1965) has put a question mark on this conclusion of Florin and mentioned that “Florin’s reconstruction was a reasonable piece of guesswork, but it must be borne in mind that it is no more than this. The same, of course, might be said of many other reconstructions of fossil plants”.
Cycas fujiana, a fossil Cycadaceae was reported by Yokoyama (1911) from early Tertiary of Japan. Florin (1933) described Cycas blomquistii as yet another fossil Cycadaceae, and Harris (1950) described Cycadites cteis from Mesozoic era of Yorkshire. From the Jurassic age of Mesozoic era, a Cycas-like megasporophyll has also been described under the name Cycadospadix hannocquei.