Lithothamnion glaciale grows as an encrusting, chalky thallus, deep reddish in colour and up to 20cm in diameter and 4mmthick. It develops simple cylindrical branchesgrowing to 15mm long and 4mm in diameter.
Reproduction
These algae are dioecious, with domed spermatangial conceptacles, carpogonial conceptacles and carposporangial conceptacles.