the Brit if Fuc/\ with particular Defci iptions of each Species. 101 



ger. Subftantia cartilagineaomnino coriacea ct tenax. jfltitudovavht 

 — ad duas ulnas. 



This Fucus is fo common and fowell known, that any longde- 

 fcription of it muft be unneceiTary : the large elliptical vcflels or air- 

 bladders, which form its moft confpicnous character, and from 

 which its trivial name is taken, iufficientlv diftinguifh it from ah 

 other Britifh fpecies. Thefe veficles are folitar} r , diftant from each 

 other, much wider than the ftalk, and decreafe regularly in fize 

 from the lowed to the uppermoft on each frond or branch. The 

 lower part of the frond is ufually deftitute of veficles as well as 

 leaves ; but there is always a finall veficle above the uppermost 

 leaves, from which the branch continues again naked to the lum- 

 mit, which is obtufe. The diftichous leaves in an advanced (late 

 are fwelled, replete with mucus, and contain numerous tubercles, 

 each having a correfponding opening on the furface of the leaf. 



It is common on every part of the Britifh coaft, on the rocks, 

 and alfo on the piles and other wood-work of the harbours, and is 

 often adorned with large tufts of Conferva poly morpha, which appears 

 particularly to attach itfelf to this fpeciesof Fucus. 



The veficles vary in fize from the bignefs of a pea to that of a 

 crow's egg, and even larger. 



48. Fucus obtusus. 



F. fronde cartilaginea ramofifTima, ramis ramulifque fub-oppo- 

 fitis erecliufculis obtufiflimis truncatis. 

 FL dng. p. 586. Withering^ vol. 3. p. 253. 

 Habitat in rupibus et faxis marinis haud infrequens — In Infula 

 Portlandiae— prope Weymouth— Exmouth.- 



I Radix 



