131 SYNOPSIS OF BRITISH SEAWEEDS. 



thor. and when once this has occurred, it is in vain to at- 

 tempt their disentanglement. 



232. strictum (The straight Ceramium)\ frond capillary, nearly 

 equal, membranaceous, irregularly dichotomous, the lower 

 forkmga distant, the upper closer, all the divisions ereci and 

 Btraight, with narrow, acute axils-, the apices straight or 

 Blightly hooked inwards; articulations colourless, those of 

 the lower dichotomies from three to four times as long as 

 broad, of the upper gradually shorter ; dissepiments (smooth 

 or hairy) opaque purple; favellie near the tips of the 

 brandies, involucrate ; tetraspores erumpent, bursting from 

 the dissepiments of the larger branches, quadrifarious, J! 

 Man. ed. 2. p. 161. (Atlas, PI. LI. Fig. 233.) 



Gongroceras strictum, Kiilz. 



Hab. On mussel-shells, corallines, etc., in tide-pools, near low- 

 water mark. 

 A beautiful species, and a tolerably definite one, consi- 

 dering the genus to which it belongs. It is known from C. 

 nodosum by its less patent branching, its more purple co- 

 lour, and different disposition of the tetraspores, besides 

 minor characters, more readily taken in by the eye than 

 the ear. Sometimes the branches are quite smooth, and at 

 other times every node of the upper branches and ramuli 

 is densely clothed with long, flexible hairs, which appear 

 to be the same pubescence that Kiitzing describes, and on 

 the presence of which he founds his genus Trichoccras. 



233. nodosum (The knobbed Ceramium): frond capillary, of 

 equal diameter throughout, rigid, dichotomous, excessively 

 divided, fastigiate ; the axils very patent ; articulations pel- 

 lucid, those of the middle of the stem from four to six times 

 as long as broad, the upper gradually shorter ; dissepiments 

 swollen ; tetraspores erumpent, two or three together on the 

 outer edge of short, accessory ramuli ; favella? at the apex of 

 accessory ramuli, Haw. Phy. Brit. pi. 90. (Atlas, PI. LI. 

 Fig. 23 i.) 



Hormoceras nodosum, Kiitz. Ceramium diaphanum, var., Wyatt. 



C. rigidulum, Griff. C. tenuissimum, J. Ag. 

 Hah. On sandy shores, often at the roots of Zostera. 



This species is generally known to British botanists, 

 though perhaps not under the name here given. It is dis- 

 tinguished from those most nearly allied to it by a certain 

 harshness to the touch, or rigidity, as well as by its very 

 patent forking. In these respects it differs from C. fasti- 

 yiatum, which it most nearly resembles. 



