Developmental stages of charophyte antheridia in accordance with Shepherd and Goodwin (1992). First developmental stage of young (A, B) and maturing (B) antheridia indicated by a green/light yellow colour or the orange colour (B) after shield cell developing (C) Autofluorescence of antheridia detected with a fluorescence microscope, scale = 139.8 µm. (D) Mature antheridia (E-F) release of spermatozoids by opening of shield cells (E) and a detailed view of antheridial filaments (F) (G) shield cells of antheridia after the release of spermatozoids containing plastids with plastoglobuli (photographs: A. Holzhausen).