Vertebrata thuyoides is a small marine algaegrowing to 15cm high in dense tufts of erect branches bornealternately and in one plane. The erect branches have 8 to 10 pericentral cells surrounding the centralaxis and are all of the same length. The whole plant is corticated, and is attached by rhizoids. It is very similar to Vertebrata fruticulosa. Pterosiphonia complanata is similar but can be distinguished by having 5 pericentral around the central cells of the axes.