(86) 



when fresh, a pale olive brown, when old, a pale yellowish brown. 

 Fructification : minute, obovate spores, attached to and nestling among 

 monihform, clavate branching filaments, which form hemispherical wart- 

 like masses, an-anged in more or less regular spiral bands running round 

 the whole of the frond almost from the base. 



The present plant is still looked upon by many as a variety of the 

 preceding, which it very closely resembles, differing chiefly in the more 

 distended and tubular stem or base of the frond, and the more regular 

 disposition of the sori in spiral bands. 



We have not seen recent specimens of the plant, but suspect that in a 

 very young state the frond must be solid, and that the hoUowness arises 

 from the breaking up of the lax cellular tissue of the axis ; ultimately 

 the whole of these large cells disappear, and nothing remains in old 

 plants except the more minutely cellular periphery. The differences in 

 the characters, we are assured in the Phycologia Britannica, are increased 

 with the depth of the water in which the plant vegetates, and are, more- 

 over, such as are generally consequent on growing in deeper water, and 

 are such as are found in other species when growing under similar 

 circumstances ; so that upon the whole the claims of this plant to specific 

 distinction rest, we fear, on rather insecure footing, even in the present 

 age of species-making notoriety. 



As a species it is said to be more common in Scotland and Ireland 

 than in England, but we have not seen either Scotch or Irish specimens, 

 ours being from Falmouth Bay, obligingly communicated by Miss 

 Warren. 



EXPLANATION OP PLATE CLX. 



Fig. 1. — StilojjJiora Lynghi/cei, natural size. 

 2. — Portion of branch witli sori. 

 3. — Transverse section of same. 

 4. — Section of sorus. 

 5. — Filaments from sorus. 

 6. — Surface cells. All magnified. 



