Spore

Spores are diaspores[?] (dispersal units) of fungi, ferns, "fern allies," and some other plants, but they also can be dormant resting stages in the life cycles of some animals and bacteria. Spores can be formed sexually or asexually, and organisms may form many different kinds of spores.

The chief difference between spores and seeds is that spores have less resources than seeds, and thus require better conditions to germinate. In compensation, spores are often very hardy, and can survive many years in dry climates.

In the case of spore-shedding vascular plants such as ferns, wind distribution results in a greater capacity for dispersal via wind currents than by setting seed.

Spores are less subject to animal predation than seeds because they contain no food, however they are more subject to fungal and bacterial predation.

Their chief advantage is that of all forms of progeny, they require the least energy and materials to produce.

In the case of vascular plants, spore is either termed homosporous or heterosporous. Vascular plant spore is always haploid. Plants that are homosporous have all spores of the same size and type. Heterosporous plants, such as spikemosses, quillworts and some water ferns have spore of two different sizes, the larger spore effectively functioning as female spore and the smaller as male.

See also sporangium.