138 svxorsis of British seaweeds. 



Funis Blamentosus, Wulf. P. friabilie I I ium 



filamentosum, Ag. Eutchinsia filam< ( aferva 



Griffithsiaua, E. Sot 

 Hah. Southern coasts of England, in several places; bul 



On submarine rocks, near low-water mark. Perennial. 



Summer. 

 This plant, which is very local on the British coasts, 

 although found in considerable plenty in a few places, is 

 interesting in a geographical view, being a native of warm 

 latitudes and reaching to its northern limit in this coun- 

 try. Until very recently, when Mr. Ealfs discovered it on 

 the Welsh coast, it had only been found in Britain on the 

 extreme southern shores. It is more plentiful in the Chan- 

 nel Islands, and along the French coast, and abounds in 

 the Mediterranean ; but the finest specimens are found 

 in the tropical ocean. In Britain it is very generally much 

 discoloured, being of a dirty grey or brownish cast, a de- 

 formity caused by its growing in comparatively shallow 

 water, and in places exposed to strong sunshine. 



LXXXIV. GRIFFITHSIA. 



210. equisetifolia {The Equisetum-leaved Griffithsia) ; stems 

 robust, cartilaginous, whorled throughout with closely im- 

 bricated, incurved, many times dichotomous ramuli, Ag. St/n. 

 p. 28. (Atlas, PI. LIII. Fig. 245.) 

 Halurus equisetifolius, Ktz. Conferva equisetifolia, Lightf. C. 

 imbricata, Huds. C. cancellata, Roth. Ceramium equise- 

 tifolium, DC. 

 Hah. Frequent on the southern and western shores of England 

 and Ireland. On marine rocks, at extreme low-water mark. 

 Perennial. Summer. 

 Griffithsia equisetifolia was first described by Lightfoot 

 in the year 1777, in his ' Flora Scotica,' on the authority of 

 a specimen communicated by Mr. Yalden from the Frith 

 of Forth ; and it is not a little remarkable that though the 

 plant has been found on most parts of the English and 

 Irish coasts, since Lightfoot's time, yet no more recent in- 

 stance of its occurrence in Scotland has been recorded, nor 

 have I received it from any of my Scotch correspondents. 

 While in fructification it perfectly agrees with others of 

 the genus, it differs considerably in habit from all, with 

 the exception of G. simplicifilum, a plant which ought 

 perhaps rather to be considered as a slender variety of the 

 present, than as a distinct species. 



