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

Remains of secretory: cavities, so-called resin or secretion bodies, in pin nules of Stephanian pteridosperms from the Blanzy-Montceau Basin (Central F rance) are examined from cuticles of four species: Dicksonites leptophylla, D. plurkenetii, Pseuodomariopteris paleaui, and ribeyronii. The distributi on 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 m odes 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 funct ions of the secretion of lipophilic substances in pteridosperm pinnules are suggested. The secretion of lipophilic substances is abundant among taxa w ith a vine-like life-form, and this may be related to special demands on pr otection of climbing or scrambling plants. (C) 2000 The Linnean Society of London.