Microspore

[4] In heterosporous seedless vascular plants, modified leaves called microsporophylls bear microsporangia containing many microsporocytes that undergo meiosis, each producing four microspores.

[3] The only heterosporous ferns are aquatic or semi-aquatic, including the genera Marsilea, Regnellidium, Pilularia, Salvinia, and Azolla.

[3] Types of Gymnosperms: As the anther of a flowering plant develops, four patches of tissue differentiate from the main mass of cells.

Four chambers (pollen sacs) lined with nutritive tapetal cells are visible by the time the microspores are produced.

[6] Microspore embryogenesis is used in biotechnology to produce double haploid plants, which are immediately fixed as homozygous for each locus in only one generation.

Without this double haploid technology, conventional breeding methods would take several generations of selection to produce a homozygous line.

Microscopic photo of spores (in red) of Selaginella . The large three spores at the top are megaspores whereas the numerous smaller red spores at the bottom are microspores.