Pterosiphonia parasitica
- kingdom: Plantae
- phylum: Rhodophyta
- class: Florideophyceae
- order: Ceramiales
- family: Rhodomelaceae
- genus: Pterosiphonia
- species: Pterosiphonia parasitica
North Saanich
British Columbia
CanadaBantry
Munster
IrelandBerwick-Upon-Tweed
Penzance
Torquay
England
United KingdomMonterey
Pacific Grove
Santa Barbara
Santa Cruz
California
United States