Heterospory is the production of spores of two different sizes and sexes by the sporophytes of land plants. The smaller of these, the microspore, is male and the larger megaspore is female. Heterospory evolved during the Devonian period from isospory independently in several plant groups: the clubmosses, the arborescent horsetails,[1] and progymnosperms.[1][2] This occurred as part of the process of evolution of the timing of sex differentiation.
eg:Male and Female cone of pine [Pinophyta]
Two different type spore bearing plant as megaspore and microspore eg. pinus
HETEROSPORY :- THIS IS A CONDITION IN WHICH AN ORGANISM (PLANTS)PRODUCE TWO DIFFERENT TYPES OF GAMETES (MORPHOLOGICALLY)i.e, ONE LARGE GAMETE AND THE OTHER BEING A SMALL GAMETE OR FLAGELLATED AND NON-FLAGELLATED GAMETES IS KNOWN AS HETEROSPORY.
EXAMPLE:- Selaginella,Salvinia.
Selaginella, Isoetes, Stylites, Marsilea, Pilularia, Regnellidium, Salvinia, Azolla and Platyzoma are the living examples
Lepidocarpon, Lepidostrobus, Mazocarpon, Plaeuromeia, Sigillariostrobiis (members of Lycopsida), and Calamocarpon, Calamostachys, Palaeostachys (members of Sphenopsoda). are extinct genera and fossils
Lepidocarpon, Lepidostrobus, Mazocarpon, Plaeuromeia, Sigillariostrobiis (members of Lycopsida), and Calamocarpon, Calamostachys, Palaeostachys (members of Sphenopsoda). These refer to the fossil genera.
The living members include: Selaginella, Isoetes, Stylites, Marsilea, Pilularia, Regnellidium, Salvinia, Azolla and Platyzoma (9 genera)
Heterospory means the formation of two distinctly different spores. The smaller one, designated as microspore later on gives rise to the male gametophyte and the larger one called megaspore gives rise to female gametophyte. Heterospory commonly occurs in all gymnosperms and certain pteridophytes such as Selaginella.
