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Background  Structural elucidation and analysis of fructifications of plants is fundamental for understanding their evolution. In case of  Ginkgo biloba , attention was drawn by Fujii in 1896 to aberrant fructifications of  Ginkgo biloba  whose seeds are attached to leaves, called  O-ha-tsuki  in Japan. This well-known phenomenon was now interpreted by Fujii as being homologous to ancestral sporophylls. The common fructification of  Ginkgo biloba  consists of 1-2 (rarely more) ovules on a dichotomously divided stalk, the ovules on top of short stalklets, with collars supporting the ovules. There is essentially no disagreement that either the whole stalk with its stalklets, collars and ovules is homologous to a sporophyll, or, alternatively, just one stalklet, collar and ovule each correspond to a sporophyll. For the transition of an ancestral sporophyll resembling extant  O-ha-tsuki  aberrant leaves into the common fructification with stalklet/collar/ovule, evolutionary reduction of the leaf lamina of such ancestral sporophylls has to be assumed. Furthermore, such ancestral sporophylls would be expected in the fossil record of ginkgophytes.    Results  From the Upper Permian of the Bletterbach gorge (Dolomites, South Tyrol, Italy) ginkgophyte leaves of the genus  Sphenobaiera  were discovered. Among several specimens, one shows putatively attached seeds, while other specimens, depending on their state of preservation, show seeds in positions strongly suggesting such attachment. Morphology and results of a cuticular analysis are in agreement with an affiliation of the fossil to the ginkgophytes and the cuticle of the seed is comparable to that of Triassic and Jurassic ones and to those of extant  Ginkgo biloba . The  Sphenobaiera  leaves with putatively attached seeds closely resemble seed-bearing  O-ha-tsuki  leaves of extant  Ginkgo biloba . This leads to the hypothesis that, at least for some groups of ginkgophytes represented by extant  Ginkgo biloba , such sporophylls represent the ancestral state of fructifications.    Conclusions  Some evidence is provided for the existence of ancestral laminar ginkgophyte sporophylls. Homology of the newly found fossil ginkgophyte fructifications with the aberrant  O-ha-tsuki  fructifications of  Ginkgo biloba  is proposed. This would support the interpretation of the apical part of the common  Ginkgo biloba  fructification (stalklet/collar/ovule) as a sporophyll with reduced leaf lamina.

Permian ginkgophyte fossils from the Dolomites resemble extant O-ha-tsuki aberrant leaf-like fructifications of Ginkgo biloba L