Ceramium deslongchampsii is a small marine red alga in the Division Rhodophyta.

This species is a relatively small alga growing as dense tufts to no more than 12 cm long.

Grows as densely branched monosiphonous axes[1] consisting of large cells showing cortication only at the nodes.

The tips of the branches are straight or slightly in-rolled and without spines.

[2] To be found on the rock, dead shells and other algae to a depth of 26 m.[2] Generally common around Britain and Ireland.