S. cirrhosa, of which it was considered to be a luxuriant variety, 

 and in ' English Botany ' both are represented on the same plate. 

 Mr. Borrer was, I believe, its first detector in this country, and I 

 am indebted to him for one of the original specimens, gathered 

 at Beachy head. Prom S. cirrhosa it may always be known, by 

 the different structure of the stem, the closer and more regularly 

 pectinated ramuli, and the greater size. 



S. plumosa appears to be peculiarly a northern plant, for 

 though first observed on the south coast of England, it is by no 

 means common there, nor are the specimens more than half the 

 size of that represented in our plate. Further north, it is much 

 more frequently met with, and becomes much more luxuriant. 

 Our figure is taken from a Welsh specimen, and those collected 

 by Sir. J. Richardson, at Colvend, in Dumfrieshire, are still more 

 beautifully feathered with long ramuli. The Continental stations 

 are all, it will be observed, from the north of Europe. I am not 

 aware of its being found on the Erench coast. 



In substance and general habit, S. plumosa has very much the 

 appearance of a Sertularia, and is almost as rigid. By Professor 

 Kiitzing it is made the type of a separate genus, on account of 

 the structure of its stem being a little different from that of the 

 typical species ; but the difference does not appear to me to be 

 sufficiently great to warrant the dismemberment of so natural a 

 group, unless it were further borne out by a difference in fructi- 

 fication. But the fructification of this, as well as of several 

 others of the Sphacelarice, is unknown. 



Fucus rudis of Esper (Ic. Euc. t. 27), which is said to be a 

 native of the shores of England and Erance, is referred by 

 Lyngbye to Sphacelaria plumosa, but if intended for this plant 

 it is indeed a very rude representation of it. Esper's figure much 

 more nearly resembles a faded piece of Battia Brunonis, a native 

 of the Southern Ocean ; but is said to have been drawn from a 

 specimen received from Normandy. 



Fig. 1. Sphacelaria plumosa : — of the natural size. 2. Segment of a branch. 

 3. Portion of one of the pectinate ramuli. 4. A cross section of the stem : 

 — all more or less highly magnified. 



