gemma

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. Botany An asexual budlike propagule as in liverworts, capable of developing into a new individual; a bud.

Century Dictionary and Cyclopedia

1. n. In botany and zoology, a bud; that which is budded; the result of gemmation. Specifically, in botany: A leaf-bud as distinguished from a flower-bud; the rudiment of a young branch.
2. n. [capitalized] In conchology, a genus of bivalve mollusks, of the family Veneridæ, containing a single small species, G. totteni or G.gemma (originally Venus gemma), about one eighth of an inch long, yellowish or rosy-white tipped with amethystine, found on the Atlantic coast of the United States. The young are retained inside the valves of the parent till their shells are formed.
3. n. In biology, one of the hypothetical units of living matter: similar to biogen, idioblast, pangen, plasome, etc.
4. n. A knoblike protuberance or nodule.

Wiktionary

1. n. bud; an asexual reproductive structure, as found in liverworts and hydra, able to produce new individuals from a cluster of cells.

GNU Webster's 1913

1. n. (Bot.) A leaf bud, as distinguished from a flower bud.
2. n. (Biol.) A bud spore; one of the small spores or buds in the reproduction of certain Protozoa, which separate one at a time from the parent cell.

WordNet 3.0

1. n. small asexual reproductive structure in e.g. liverworts and mosses that detaches from the parent and develops into a new individual