RHODYMENIACEiE. 171 



Rhodophyllis appendiculata. The ciliated 

 Rhodophyllis. 



Fronds growing in tufts, from one to two inches high, 

 narrower and thicker than those of B. bifida, much divided, 

 opake, of a brownish-red colour, their edges fringed with 

 leafy cilia, which contain tetraspores. 



This plant has but recently been raised to the rank of 

 a species. It was formerly considered to be a variety of 

 R. bifida, and is figured and described in the f Phyco- 

 logia Britannica' as R. bifida, var. ft. ciliata. It is very 

 rare. 



Genus LXXIV. PLOCAMIUM. 



Frond somewhat cartilaginous, linear, flattened, pinnately 

 divided, composed of two strata of cells ; the inner longitu- 

 dinal and oblong, the outer many-sided and small. Spores 

 on filaments radiating in tufts from a basal placenta in hemi- 

 spherical conceptacles, which are either with or without 

 stalks ; tetraspores zonate, oblong, in small leaf-like stichi- 

 dia. — Plocamium, from the Greek plokamos, braided hair. 



This is a very beautiful and widely distributed genus, 

 all the species of which are remarkable for their bril- 

 liant colour and handsome tree-like fronds. 



Plocamium coccineum. Scarlet Plocamium. 



Frond cartilaginous, narrow, flattened, much divided ; 

 branches spreading, irregularly alternate ; branchlets awl- 

 shaped, curved, set with comb-like spurs on their inner 

 side. Spores in solitary, marginal, stalkless conceptacles ; 

 tetraspores zonate, in leaf-like stichidia on the inner sides 

 of the ramuli. 



This is one of the most abundant, and is probably the 



