A cell or cell structure that reacts to changes in humidity with a change in shape, and thereby assists in the dispersal of spores; elaters can be either on the spore (e.g. in Equisetum) or in the sporangium.
The erectile appendages of the spores of Equisetum.
In botany, elongated cells with spirally thickened walls, associated with spores in the capsules of liverworts and mosses.