Note: Spores are produced differently in the different
classes of cryptogamous plants, and as regards their
nature are often so unlike that they have only their
minuteness in common. The peculiar spores of diatoms
(called auxospores) increase in size, and at length
acquire a siliceous coating, thus becoming new diatoms
of full size. Compare {Macrospore}, {Microspore},
{O["o]spore}, {Restingspore}, {Sph[ae]rospore},
{Swarmspore}, {Tetraspore}, {Zo["o]spore}, and
{Zygospore}.
(b) An embryo sac or embryonal vesicle in the ovules of
flowering plants.
2. (Biol.)
(a) A minute grain or germ; a small, round or ovoid body,
formed in certain organisms, and by germination giving
rise to a new organism; as, the reproductive spores of
bacteria, etc.
(b) One of the parts formed by fission in certain
Protozoa. See {Spore formation}, belw.
{Spore formation}.
(a) (Biol) A mode of reproduction resembling multitude
fission, common among Protozoa, in which the organism
breaks up into a number of pieces, or spores, each of
which eventually develops into an organism like the
parent form. --Balfour.
(b) The formation of reproductive cells or spores, as in
the growth of bacilli.