The structure and development of hairs on the thallus ofGelidium caulacantheumJ. Ag.

Abstract
In G. caulacantheum unicellular hairs are characteristically developed at apices and most are lost later as the thallus matures, leaving a persistent hair scar. The structure of the hairs, reported for the 1st time in this genus, is identical to that described for other Gelidiales. Some possible roles of these structures are discussed in relation to their frequency and persistence in material from natural habitats, and in response to some experimental treatments.