Remains of secretory cavities in pinnules of Stephanian pteridosperms from Blanzy-Montceau (Central France): a comparative study

Remains of secretory cavities, so-called resin or secretion bodies, in pinnules of Stephanian pteridosperms from the Blanzy-Montceau Basin (Central France) are examined from cuticles of four species: Dicksonites leptophylla, D. pluckenetii, Pseudomanopteris paleaui , and P. ribeyronii . The distribution of the secretion bodies in pinnules may be (1) simple and in consistent patterns, (2) random, but topographically unequal, or (3) completely random. Differences in the morphology of the bodies may be related to different modes of development of the secretory cavities, i.e. schizogenous or (schizo-) lysigenous development. The value of using these features in fossil plant taxonomy is discussed. Finally, some comments on possible ecological functions of the secretion of lipophilic substances in pteridosperm pinnules are suggested. The secretion of lipophilic substances is abundant among taxa with a vine-like life-form, and this may be related to special demands on protection of climbing or scrambling plants.