Question

What is heterosporous?

Answer 1

Heterospory
Heterospory is the production of spores of two different sizes and sexes by the sporophytes of land plants. Heterospory was evolved from isospory independently by several plant groups; the clubmosses, the arborescent horsetails,[1] and progymnosperms[1] in the Devonian period[2] as part of the process of evolution of the timing of sex differentiation.[3] Heterosporic plants produce small spores called microspores which either germinate to become free-living male gametophytes or have reduced male gametophytes packaged within them, and larger spores called megaspores that either germinate into free-living female gametophytes, or which have a female gametophyte packaged within them which is retained in and nurtured by the sporophyte phase, a condition referred to as endospory. Heterosporous species are thus usually dioicous, a condition that promotes outcrossing. Some heterosporous species produce micro- and megaspores in the same sporangium, a condition known as homoangy, while in others the micro- and megaspores are produced in separate sporangia (heterangy). These may both be borne on the same monoecious sporophyte or on different sporophytes in dioecious species.