Abstract
In Equisetum both the spore and the rhizoidal and first-formed prothallial cells contain sac-like cytoplasmic particles limited by a unit membrane. After KMnO4 fixation these bodies resemble the spherosomes described from earlier studies (e.g. Frey-Wyssling et al., 1964). They are bounded by a unit membrane, have a diameter of 0.8–1.7 μ and a fine granular content. After double fixation with buffered glutaraldehyde combined with an osmium post-fixative, or triple fixation with buffered formaldehyde added, the bodies resemble microbodies in fine structure. They have a thin unit membrane, a more coarsely granular matrix than after KMnO4 fixation and very often a core like a 0.5 μ cluster of tubules or discs of around 200 Å in diameter. When spores are fixed in glutaraldehyde the bodies often show cytoplasmic invaginations or inclusions, which is never the case when they are fixed with KMnO4