Devonian Spores of Kryshtofovichia africani Nikitin (Tracheophyta): Morphology and Ultrastructure

Аннотация

The morphology and ultrastructure of spores of the Devonian plant Kryshtofovichia africani Nikitin are examined. The structure of ultrathin exine megaspores of K. africani is established. The exine consists of two layers: granular ectexine and lamellate endexine. Microspores have a lamellate ultrastructure with a trend toward loosening and formation of the granular structure towards the ectexine outer part. Heterospory of K. africani is apparent in both morphological characters and sporoderm ultrastructure of micro- and megaspores.