Biol. a bud of a moss or a reproductive body of an alga or of certain sponges; small gemma
See gemmule in American Heritage Dictionary 4
(jĕmˈyo͞ol)
noun
A small gemma or similar structure, especially a reproductive structure in some sponges that remains dormant through the winter and later develops into a new individual.
A hypothetical particle of heredity postulated to be the mediating factor in the production of new cells in the theory of pangenesis.