Heterospory

Under heterospory is understood in botany, in contrast to Isospory, the phenomenon that the spores of a species have different sizes and are constructed differently. Male spores are smaller here and reserve fuel poorer than female. The former are referred to as micro pores, the latter as megaspores (or macro pores ). The haploid gametophytes resulting from them ( prothallia ) are also different sizes: Male gametophytes are smaller than females.

The heterospory is a feature of moss ferns ( Selaginella ), the Brachsenkräuter ( Isoetales ), the water fern ( Salvinia, Azolla, Marsilea and Pilularia ) and the seed plants. In the latter, there is Endosporie, which means that the gametenbildende generation ( gametophyte ) remains in the spore and does not form a separate plant more.

Are the male and female spores, however, the same size ( this is regarded as more primitive or more original feature and applies to most genuine ferns ), one speaks of Isospory.

• Botany