Fine Structure of the Spermatozoid of Zamia: The Vierergruppe

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.