72 



LIST OF THE BRITISH 



Order XIII. CEEAMIACEiE. 



Eose-red or purple sea-weeds, with a filiform frond, 

 consisting of an articulating, branching filament, com- 

 posed of a single string of cells. Fructification : — 1. Fa- 

 vellss, berry-like receptacles, containing numerous angu- 

 lar spores ; 2. Tetraspores attached to the ramuli, or 

 more or less immersed in the substance of the branches, 



LXXX. Ptilota. 



Frond compressed, inarticulate, distichous. Fructi- 

 fication : — 1. Eoundish, clustered favellaB, surrounded 

 by an involucre of short ramuli ; 2. Tetraspores attach- 

 ed to or immersed in the ultimate pinnules. 



1. Ptilota plumosa. 



2. „ sericea. 



LXXXI. Microcladia. 



Frond filiform, compressed, inarticulate, dichotomous, 

 Fructification: — 1. Eoundish favellse ; 2. Tetraspores 

 immersed in the ramuli. 



1. Microcladia glandulosa. 



