Acrosorium venulosum (Zanardini) Kylin

Acrosorium ciliolatum

Also known as Acrosorium uncinatum sensu Kylin and Acrosorium ciliolatum sensu auctorum (Europe).
Common name: Red Hook Weed (English)
Description: Flattened, membranous, deep red fronds, 30-150(-200) mm long. Frond deeply divided into linear-lanceolate, irregularly branched segments, often terminating in incomplete hooks. Margins toothed, often ± proliferous. Frond traversed by network of microscopic veins, macroscopic veins absent.
Habitat: On rocks and epiphytic, lower intertidal and subtidal, widely distributed, occasional.
Similar species: Frequently confused with Cryptopleura ramosa, a very variable spcies that occurs in a similar range of habitats. Acrosorium is generally more frequent subtidally and Cryptopleura ramosa is more common in rockpools.
Note: This species was known for a time as Acrosorium ciliolatum a species with a type from Tasmania. A 2021 paper has shown that European specimens from Spain and the UK are not phylogentically related to southern Hemispehere material.

Link: Algaebase

Species list

Photographs © M.D. Guiry