hapteron

(pl. haptera) 1. See holdfast.

2. The outer wall of the spore in species of Equisetum (horsetails). It differentiates into an elongated X-shaped structure, the arms of which are tightly coiled around the spore. Following release of the spores from the sporangium the haptera dry out and uncoil, this movement assisting in the dispersal of the spores. They are thus similar in function to elaters.