Bryophytes of Australia Glossary

Compiled by P. Bolton


leaf costa

Awn: The bristle at the leaf apex formed by an excurrent costa. (see also arista and hairpoint)

Costa: Thickened tissue forming a midrib or nerve, present in most mosses and some liverworts.

Excurrent: Where the costa extends beyond the apex of the leaf.

Percurrent: Where the costa extends to the leaf apex, or shortly before.