Description: Thallus erect to 15 cm long, fan-shaped with the monostromatic lamina deeply devided into into long narrow branches 3 - 10 mm wide and pointed. These branch with irregular small dentations or teeth, some hooked and sickle-shaped. Only microscopic veins present, macroscopic veins are never present.

Habitat: Epiphytic or on corallines on rock, epiphytic, epizoic in deep low-littoral pools and sublittorally to 30 m.

Distribution: Mainly on the west coasts of the British Isles north to Orkney and south to Channel Islands. Europe: Mediterranean, Azores, Portugal, Atlantic coasts of Spain and France. Further afield: Canary Islands and South Africa.

Similar Species: Cryptopleura ramosa may appear similar but the hooks are marginal rather than marginal and terminal and the veins are only microscopic.

Distribution Map from NBN: Acrosorium venulosum at National Biodiversity Network mapping facility, data for UK.

iNaturalist: Acrosorium venulosum at iNaturalist World Species Observations database.

WoRMS: Acrosorium venulosum at World Register of Marine Species. Accepted name: Acrosorium venulosum (Zanardini) Kylin, 1924. AphiaID: 144734.

Classification: Biota; Plantae; Biliphyta; Rhodophyta; Eurhodophytina; Florideophyceae; Rhodymeniophycidae; Ceramiales; Delesseriaceae; Phycodryoideae; Cryptopleureae; Acrosorium