Mr. Woodward^ Obfervations upon the Generic Char ail er of Ulva. 47 



The genus Ulva was adopted by Linnaeus from Dillenius, and 

 the chaiafter ftandsin the Genera P/antarum in thefe words — " Fruc- 

 iijicdiiones in metnbrand vejiculari abfque fronde.'^ In the Syjlema Vegeta- 

 bilium, the efTcntial charadler of the genus is thus given — " Fruiii- 

 Jicationes in membrand diaphand:'' and this characflcr is adopted by 

 Hudfon, Lightfoot, and all the Linnaean authors, notwithftanding 

 a great part of the plants which are arranged in this genus can by 

 no means be confidered as agreeing with it. Amongfl: the fpecies 

 enumerated by Linnaeus himfelf, in the Species Planiarum, are fome 

 which only agree in part with the generic charadler, and others 

 which are totally difcordant from it. Of the firfl: defcription are all 

 thofe fpecies which were adopted from the Synopjis, htiluca, latijima, 

 and the reft, in which no aftual fruflification has been hitherto 

 difcovered; in confequence of which it is there called " Genus 

 Jierile." Amongft the latter are pruniformis and granulata, which, 

 are both fphasrical, and filled with a gelatinous pulp, in which no 

 fru6lification has as yet been obferved. The Ulva pavonia is the 

 only one amongft the fpecies enumerated by Linnseus, in which 

 fruftification vifibly exifts ; and this, which can fcarcely be faid to 

 confift of a diaphanous membrane, has by fome authors been confi- 

 dered as a Fucus^ from the circumftance of the feeds being difpofed 

 in feparate fafciae, and not difperfed over the whole furface. The 

 Flora AngU'ca includes fpecies which accord ftill lefs with the effen- 

 tial charadler; fome being round and fiftulofe, and amongft thefe 

 the fijlulofa is undoubtedly opake ; and others filiform, amongft 

 which it is fufficient to mention plumofa, than which nothing can. 

 be farther removed from the generic charadler. 



Befides this anomaly, which might be removed by forming one 

 or more new genera ; the charadler is in itfelf vague and doubtful 

 as neither the kind, nor the precife fituation of the fruilification is 



pointed; 



