Description: Varies from thinly encrusting patches to smoothly rounded lobes to tall, chimney-like growths with large terminal oscules or laterally spreading masses of anastomosing branches. The shape of this species is highly variable. Grey-brown to purple-brown, evenly coloured over all of the sponge. The purple-brown form may be characteristic of better illuminated sites in shallow or clear water. Goes whitish in spirit (?consistently). Very soft and flexible - one of the softest Haliclona species. The oscules are terminal on raised lobes, or at the ends of tall chimney structures. The oscules are flush with the rounded ends of these chimneys, and do not have a raised membranaceous edge as in many other Haliclona species.

Habitat: Frequent in water 10-30m deep in moderately exposed sites, and also in sites which are sheltered but have moderate tidal streams. The tall chimney-like form only develops in the more sheltered conditions. Also present in very shallow water and under stones in the intertidal.

Distribution: Widespread in Ireland; W. coast of Scotland; English Channel. "Shetland; France; Mediterranean; Azores; West Africa."

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

iNaturalist: Haliclona cinerea at iNaturalist World Species Observations database.