Carpomitra Costata

Also known as Carpomitra cabrerae Kützing.

Description:
Frond narrow, delicate, light brownish-yellow to dark brown, 1-2 mm wide and up to 200 mm long. Branching irregularly dichotomous, midrib more or less obvious. Reproductive structures formed on a mitre-shaped apical receptacle.

Habitat:
On stones exclusively in the sub tidal to 30 m. Terminal tufts of hair 4-6 mm long present in summer. Rare. Many reported records are repeats of single drift findings in the 19th century when the species was a cause célèbre for Victorian collectors.

Distribution:
S and W England and Ireland; W Scotland.

Key characteristics:
Mitre-shaped receptacles, terminal tufts of hairs, narrow thallus with midrib.