the Briti/h Fuc'ty wilb particular Defcriptions of each Species, 173 



the folic! fubflance of the plant, but rather from the margins being 

 eontradled as it were, and drawn through their whole length to 

 one fide — fo that it has the appearance of being channelled rather 

 than the reality. However, as the appearance is conftant, we are 

 glad, in arranging fo numerous a family, to take advantage of it, and 

 eftablifli a new order founded upon this circumftance. 



This plant is found on all rocky iTiores. Where it is expofed to 

 frefti water, the points of the branches, as well as the branches 

 themfelves, are longer and coarfer, and the tubercles more nume- 

 rous, and confequently appear to be more tumid. We obferved . 

 this particularly in the river Severn. 



38. FUCUS PATENS. 



F. fronde dichotoma lineari apicibus obtufiufculis planis ; tu- 

 berculis fubglobofis fparfis. 



Habitat prope Marazion in littore Cornubienfi, ct apud llfra-. 

 combe in com. Devon, frequens. 



Radix callus — Frons bafi ipsa furculofa, unde plurimi caules con- 

 ferti enafcuntur — Frons linearis, et hinc leviter canaliculata — Rami 

 omnes dichotomi, dichotomiis patentibus — Apices ramorum plani, 

 tuberculorum immunes, obtufiufculi — Altiiudo variat 2— 6uncialis 

 —Color plerumquebrunneus — Subjlantia membranacea — FritSlifcatio, . 

 tubercula fubglobofa prominula per extremes ramos fparfa. 



Obf. Habitus F. crifpi var. cequalis., at margines ramorum longitu- 

 dinaliter levius inflexi, unde canaliculati videntur rami nee plani. 



Hitherto we have noticed this plant only at llfracombe in Devon- 

 ftiire, and near Marazion in Cornwall. Some care is neceflary to avoid 

 confounding it with fome of the varieties of F, crifpus. The leading 



mark . 



