lhA_generic Chaiacler ofUha, &c, 49 



to their place of growth by feme point of the under furfacc. The 

 greater part are very much attenuated immediately above the bafe, 

 but fuddenly dilate, and are divided. into numerous fegments, which 

 are always of the fame fubftance throughout. The filiform and 

 comprcfTed Uh^ are cither fimple or branched; but the branches 

 are merely divifions of the frond, which may therefore ftridly be 

 called continuous or uniform. The frudification of thefe is un- 

 known, excepting only the U/va diaphana, and rubra of Hudfon ; in 

 the former of which it confifls of numerous minute grains or feeds, 

 difperfed throughout the whole internal fubftance: the fruQifica- 

 tion of the latter has not yet fallen under the obfervation of the 

 author. Amongft the membranaceous U/vce, the pnvonin, cocclnea, 

 dlchotoina, atomaria and Ugulata, exhibit a fructification, confifting of 

 numerous minute grains or feeds, thickly fcattered on both fides 

 immediately under the epidermis, fometimes crowded, but moftly 

 fingle. The frutSlification of the laHuca^ lat'iffinui, comprejfa, umbili- 

 cata, and laciniata is entirely unknown. 



This genus, and that of Tremclla, fo nearly approach each other, 

 that it is extremely difficult to afceitain their proper limits. The 

 original defign appears to have been, to confider fuch as were mem- 

 branaceous as Ulva., and fuch as were gelatinous as Tremellct : but 

 this diftindtion has been by no means adhered to; there being gela- 

 tinous U/vif, and membranaceous Treme/I^e, to be met with in almoft 

 every author. Perhaps the befl: diflin6tion would be, to confider 

 all thofe which are membranaceous, and in which no vifible frufti- 

 fication exifts, as belonging to the genus Tremella ; and to arrange 

 thofe in which the frudlification is known, and fuch as are filiform, 

 although without any perceptible fruclification, with the Uhce, It 

 muft neverthelefs be evident, that fuch an arrangement would 

 entirely fubvert the genus Uha as it flands in Sp. PI, and ver}' much 



Vol. III. H confufe 



