CONFERVA TETRICA. 



C. fihmentis decompofito-pinnatis, pinnis piunulifque alternis, extremis 

 curvatis; articulis longiufculis, capfulis fub-folitariis globofis pedun- 

 culatis. 



On Fuci and on Rocks in the Sea. Common about the Mumbles and in ether 

 parts of the Peninfula of Cower. 



C. TETRICA is extremely plentiful in the pools left by the tide on the coafts 

 of the peninfula of Cower, where it grows either on the rocks or parafitically on 

 the larger fuci. The root is a fmall callus from which feveral ftems arife, form- 

 ing thick entangled bundles of a dull or brownifh red color, wholly devoid of 

 glofs, and frequently attaining the length of fix or eight inches. The principal 

 ftem in thicknefs is about equal to horfe hairs. The primary fhoots are difpofed 

 without much obfervable order and of unequal lengths ; they are winged with 

 alternate branches, which are again pinnated with others alfo regularly alternate, 

 and thefe are befet with fhort curved ramuli, of which the length is variable but 

 always fhort in comparifon with that of the other branches. The joints are 

 cylindrical ; their length in the principal branches is at leaft equal to thrice 

 their thicknefs, but it is much lefs in the fmaller ones. The capfules, of which 

 feldom more than one occurs on any of the ramuli, are globofe, and placed on a 

 fhort penduncle. 



Although this plant fo ftrikingly differs in its greater fize and appearance in 

 almoft every refpe£f from C. rofea, yet it is not eafy to find a fpecific difference 

 when examined with the affiftance of a microfcope. The principal difference is 

 then obfervable in the ultimate ramuli and in the difpofition of the capfules ; the 

 former in C. rofea are of regular lengths and truly pinnated; in C. tetrica they 

 are again divided with fhort curved and fomewhat fpine-like ramuli. In C. rofea 

 ii 



