microspore

A spore that gives rise to a male gametophyte and is smaller than a megaspore.

In botany, an asexually produced spore of small size as compared with others produced by the same species: the homologue of the pollen-grain of phanerogams.

In zoology, one of the spore-like elements, of exceedingly minute size, but very numerous, produced through the encystment and subsequent subdivision of many monads.

One of the exceedingly minute spores found in certain flowerless plants, as Selaginella and Isoetes, which bear two kinds of spores, one very much smaller than the other. Cf. macrospore.

A small spore.

smaller of the two types of spore produced in heterosporous plants; develops in the pollen sac into a male gametophyte