Thorea

Thorea is a genus of freshwater algae in the Phylum Rhodophyta (red algae). Thorea is a small alga with filaments up to 200 cm long, dark green in colour and not red as are marine Rhodophyta. The filaments have only as few secondary branches.

Thorea is distributed throughout temperate and tropical regions.

There is only one species of Thorea in the British Isles: Thorea hispida (Thore) Desvaux (Synonyms: Thorea anadina Lagerheim et K.Mobius, T. lehmannii Horneman and T. ramosissima Bory).

The first record of Thorea ramosissima in the British Isles is in Harvey's Manual (1841) : Found in a pool in a bog in the Co Donegal Mountains, going from Letterkenny to Dunfanaghy; July. These specimens are in the Ulster Museum (BEL: F42–F47), but proved to have been incorrectly identified and were specimens of Batrachospermum.