Stangeriaceae


Stangeriaceae is the smallest family of the cycads, including only two extant genera, Stangeria and Bowenia. The family has been recognized based on some shared characters such as the presence of fused vacularized stipules, the lack or irregular production of cataphylls, and a few other anatomical traits. Molecular evidence suggests that the two genera of the Stangeriaceae belong in different positions within the Zamiaceae.
Though today the family occurs only in South Africa and Queensland, Australia, potentially related fossils are found in other places in the globe. Cladistic studies suggested that the fossil taxon Mesodescolea the Lower Cretaceous of Argentina has affinities with the Stangeriaceae, being sister to Stangeria. This highly lobed fossil leaf from has been reinterpreted as an early angiosperm. Another fossil from the Lower Cretaceous of Argentina, Eobowenia incrassata, has been suggested as the oldest relative of Bowenia. The Paleogene genus Eostangeria from North America and Europe may also have affinities with the Stangeriaceae.