Dictionary Definition
hydroid n : colonial coelenterates having the
polyp phase dominant [syn: hydrozoan]
User Contributed Dictionary
English
Noun
- Any of many colonial coelenterates that exist mainly as a polyp; a hydrozoan
Adjective
- Of or pertaining to such creatures
Extensive Definition
Hydroid may refer to:
Marine Biology
Hydroids are coral-like animals living in Antarctic seas (Ross sea, etc.).Botany
In mosses, hydroids are water conducting tissues analogous to tracheids. However, they lack any pitting or surface texture.Hydroids have been found in some Rhynie chert
plants, including Aglaophyton,
where they were initially mistaken for xylem vessels.