SEA WEEDS 367 



contains the Buck's-horn sea weed which grows at and beyond 

 low-water mark on the south and west coasts, where it is sometimes 

 washed up on the beach during storms. Its fronds are flattened 

 and two-edged, freely branched, and the upper branches are re- 

 peatedly forked, and terminate in fan-shaped, cleft branchlets. 

 Both branches and branchlets are fringed with slender cilia, in 

 which the spores are embedded. It is a handsome weed, of a bright- 

 red colour and a somewhat coral -like form. 



Allied to this is Gelidium corneum, with flattened, horny fronds, 

 repeatedly pinnate, with the smallest branchlets obtuse and narrower 

 at the base. The spores are contained in conceptacles near the ex- 

 tremities of the branchlets, and the tetraspores are imbedded in 

 club-shaped branchlets. There are a large number of varieties of 

 this species, differing in form, size, and the mode of branching of 

 the fronds. The size varies from one to five or six inches, and the 

 colour is red or reddish green. 



In the genus Gracilaria the frond is thick and horny, and the 

 surface cells are very small, while the central ones are large. The 

 spores, formed on necklace -like threads, are enclosed in sessile 

 conceptacles along the branches, and the tetraspores are imbedded 

 among the surface cells of the fronds. The only common species 

 is G. confervoides, with cylindrical cartilaginous fronds bearing 

 long thread-like branches, sometimes reaching a length of two feet. 

 The spore conceptacles are situated on the slender branches, giving 

 them a knotted or beaded appearance. The colour is a dark purple, 

 which rapidly fades when the weed is placed in fresh water or 

 left exposed to the air. Two other species G. multipartita and 

 G. compressa are rare. 



Calliblepharis ciliata, perhaps more commonly known as 

 Rhodymenia ciliata, has a branching root, short round stem, and 

 a broad, crisp frond that is generally ciliated. Sometimes the 

 frond is simple and lanceolate, with small leaf-like appendages on 

 its edge ; and sometimes it is deeply cleft. The spores are arranged 

 in beaded threads in sessile conceptacles on the marginal leaflets. 

 Another species of the same genus (C. jubata) is very similar in 

 structure, but is of a duller-red colour, gradually changing to olive 

 green at the tips ; and it has its tetraspores in the cilia only, while 

 in C. ciliata they are collected in patches in all parts of the frond. 

 Both species grow in deep water, and are frequently washed up 

 during storms. 



The large genus Nitophyllum contains some beautiful rose-red 



