94 BRITISH SEA-WEEDS. 



fore, clearly visible. The species are not numerous; 

 but the genus is well represented on our coasts, where 

 three kinds are abundant, and a fourth is occasionally 

 found. The remainder are natives of tropical, or almost 

 tropical regions. 



Rytiphloea pinastroi&es. Pine-like Rytiphloea. 



Eronds from a few inches to about a foot high, cylin- 

 drical, irregularly and densely branched, shrub-like ; the 

 main branches alternate, their lower parts clothed with 

 short, awl-shaped branchlets; the secondary branches elon- 

 gate, spreading or recurved, curled inwards at the tip, 

 their upper side furnished with two rows of straight or 

 hooked branchlets, arranged generally in pairs, and giv- 

 ing the branch a comb-like appearance. Spores in ovate, 

 stalked conceptacles on the inner sides of the upper branch- 

 lets ; tetraspores tripartite, in double rows, in lance-shaped, 

 stalked stichidia. 



This plant is in perfection in winter and in early 

 spring, and is abundant in many localities on the south 

 coast and in the Channel Islands. It grows on sub- 

 marine rocks, near low-water mark, and is, therefore, 

 generally beyond the reach of the collector. Numer- 

 ous specimens are, however, thrown up during every pe- 

 riod of rough weather. When fresh, it is of a dull red 

 colour, which changes to black in drying. It will not 

 adhere to paper. 



Rytiphloea complanata. Flat Rytiphloea. 



Fronds from two to four inches high, shrub-like, flat, al- 

 ternately branched, of a brown-red colour, marked through- 

 out with curved, transverse stripes ; the lower part of the 

 stem naked, or sparingly furnished with short branchlets ; 



