4$ Mr. Woodward'/ Obfervatiom upon 



pointed out ; and fomc of the acknowledged fuci may^undoubtedly 

 be confidered as having their fructification fituated in a diaphanous 

 membrane. Having dated thefe objections to the p relent generic 

 character, the following is propofed, not as a perfect one, but as lets 

 erroneous, and as better according with the numerous fpecies at 

 prefent arranged under this genus ; and this principally with a view 

 to induce others who are better qualified, to take the matter into 

 confideration, and at length eftablifli one on fuch fixed and natural 

 principles as may remain permanent, without need of future re- 

 vifion. 



Ulva. 



Char. ejf. Frons membranacea feu gelatinofa, fructificatio (fi 



adfit) per totam frondem quaquaverfim fparfa. 

 Char. nai. Radix nulla nifi bafis frondis paululum explanata. 



Frons continua, fimplex vel ramofa, membranacea 

 feu gelatinofa. 



Fructificatio — granula feu femina per totam fron- 

 dem fparfa, folitaria vel congefla, intra fubftantiam 

 vel fub epidermide fita. 



The plants belonging to this genus adhere to thefubmarine rocks 

 and ftones, to piles or planks, and not unfrequently to other 

 plants, by an expanded difc, a fmall bulbiform callus, or an un- 

 formed gelatinous lump ; all which are merely the bafe of the frons 

 fomewhat dilated. The frons is either membranaceous or gelati- 

 nous ; the former is either plane or tubulous, and nfually diapha- 

 nous ; the latter either filiform or comprefTed, folid or fiftulous, 

 diaphanous or opake. Amongft the membranaceous Ulva fome 

 are umbilicated, and have not any vifible root, appearing to adhere 



to 



