Sporogenesis and gametophyte development in Senecio glaucus were studied in this study. Flowers and buds in different developmental stages were removed, fixed in FAA70 , stored in 70% ethanol, embedded in paraffin and sectioned at 7-10 μm with a microtome. Staining was carried out with PAS and contrasted with Hematoxylin. The results showed that anthers are tetrasporangiate and anther tapetum is of the amoeboid type. Microspore tetrads are tetrahedral and isobilatral. Pollen grains are bicellular at shedding time. The most of microspores (about 60%) are large in size and vacuolated considerably. They degenerated in the late stages of anther development but smaller ones are functional microspores. Ovule is anatropous, unitegmic and tenuinucellate. A 7-celled embryo sac is formed corresponding to the Polygonum type. The shape of megaspore tetrads is both tetrahedral and T-form. Functional megaspore is the chalazal one. Embryo sac is very small at the beginning of development, so that its nuclei are arranged as linear, but later its size increases. Antipodal cells are perennial and their number increases up to 8-14. Their nuclei become polyploid. They were also able to form an embryo at the chalazal pole in about 30% of florets, which detects gametophytic apomixis in this taxon. S. glaucus may be considered facutatively apomictic species with predominating sexual reproduction.
