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FINE STRUCTURE OF THE SPERMATOZOID OF ZAMIA: THE VIERERGRUPPE

A B S T R A C T The spermatozoids of Zamia integrifolia were examined by electron microscopy in order to clarify the structure of a fibrous organelle underlying the flagellar basal bodies. The ultrastructure of this organelle was found to resemble one similar in organization occurring in Marchantia spermatozoids and termed the Vierergruppe. Therefore the term is extended to include this structure in the Zamia spermatozoid. The Vierergruppe of Zamia is interpreted as composed of an upper (distal) layer of keeled microtubules and a lower (proximal) layer of vertical fins with lateral processes that give a three-layered appearance to this component. THE VIERERGRUPPE first was described by Carothers and Kreitner (1967) in a study of the ultrastructure of spermatozoids of Marchantia polymorpha. This structure is associated with the basal bodies of the flagella and consists of four layers. The outermost layer is composed of keeled tubular elements which are continuous with an array of parallel, cytoplasmic microtubules. The other three layers of the Vierergruppe of Marchantia form a unit composed of parallel fins, compartments, and tubules. The Vierergruppe plus the associated cytoplasmic microtubules may be termed the spline apparatus (Carothers, personal communication). Vierergruppe-like organelles have been reported