Phytoferritin in the reproductive cells of a fern, Pteridium aquilinum (L.) Kuhn

Electron-opaque aggregates of various forms are described from dedifferentiated plastids in the egg, spore mother cells and young spores of Pteridium. X-ray microanalysis shows them to be phytoferritin. The phytoferritin seems to be generally similar to that described from other vascular species, and fungi, but is unusual in the presence of readily detectable amounts of calcium. The aggregates of phytoferritin in Pteridium are not evidently crystalline, but crystallinity is nevertheless revealed by optical diffractometry. The existence of amorphous phyto­ferritin is questioned.