THE MARINE BOTANIST. 171 



RHODYMENIACE^. — RHODYMENIA 

 TRIBE. 



Sea-weeds of a brown-red^ purplish or blood-red 

 colour, with flat or filiform inarticulate fronds, sur- 

 face cells minute, rarely disposed in filaments. 

 Fructification of two kinds. 1. Conceptacles {coc- 

 cidia) external or partly immersed, containing a 

 mass of spores. 2. Tetraspores dispersed through 

 the whole frond, or collected in indefinite cloudy 

 patches. 



The leafy plants of this tribe are thicker in 

 texture than those of the preceding*. Rhodymenia 

 bifida, however, is nearly as delicate as a Nito- 

 phyUum, and in the absence of fruit, may possibly 

 be mistaken for N. Gmelini ; when viewed through 

 the microscope, the structure appears much closer and 

 denser than in that genus. In the Stenogramme in- 

 terrupta the tetraspores form round, clearly/ defined 

 sori : these J first noticed on Minehead plants in 

 1848, but it is not until recently that specimens have 



