Cellaria salicornioides is an erect bryozoan, composed of jointed dichotomous branches. The colonies form delicate diffuse tufts, approximately 4-5 cm in height and white in colour. The branches are slender and the internodes are long, frequently 5–10 mm in length and 0.2-0.5 mm in diameter. The internodes are generally cylindrical, but sometimes become thickened at the tip to give a club-shape. Autozooids are typically hexagonal or oval in outline. In adjacent series, autozooids usually alternate strictly and are not in contact with the autozooids directly above or below them in the same series, but this can be disrupted. The colony is anchored by chitinous rootlets.
The species is able to colonise coarse gravel and sandy bottoms. It ranges from shallow subtidal water to depths of 100 metres. The species serves as a substrate for many epibionts including species of Bryozoa, Rhodophyta, Sarcodina, Urochordata, Annelida and Porifera.
Cellaria salicornioides is a warm temperate species that is widely distributed in the Mediterranean. It occurs off the coast of the British Isles in the south and west, with records also coming from the Isle of Man and Shetland.