title: An ultrastructural study of the differentiation of the spermatozoid of Equisetum.
mesh_terms: D002454:Cell Differentiation; D002467:Cell Nucleus; D004721:Endoplasmic Reticulum; D006056:Golgi Apparatus; D008540:Meiosis; D008854:Microscopy, Electron; D008870:Microtubules; D008928:Mitochondria; D059828:Plant Cells