84 acotylUdons.- — alg.e. Cerammm. 



rigid, generally olivaceous, scarcely jointed, truly torulose or 

 inflated at intervals, formed of a thicki&h membrane, whose 

 texture is evidently cellular. 



1. h.fiuviatilis, filaments subsimple olive-green torulose atte- 

 nuated, intervals between the swellings cylindrical much longer 

 than they are broad. Ag.p. 70. Conferva fliiviatilis, Dilhu. 

 Conf. t.'29. E. B. t. 17H3. Light/, p. 985. 



Hab. In the beds of alpine torrents, upon the rocks near Comrie, 

 4 m. west of Crieff, Dr. Stuart. Craig-hall, near Edinb., Mr. Yal- 

 den. Rare about Glasg. ; in a rivulet on the hill to the north of 

 Milngavie, Hopk. In the bed of the Clyde near the falls, Mr. Tur- 

 ner and Hook. Not uncommon about Edinb., Mr. Greville. 



Filaments thick, tufted, elongated, from 2 to 5 inches in length, atte- 

 nuated at the base and at the extremity. 



14. GRIFFITHSIA^ 



Seeds- immersed in a gelatine, and surrounded by an involucrum. 



1. Gr. corallina, crimson much branched, articulations swelling 

 upwards thrice as long as broad, the fertile ones fringed at the 

 summit with short incurved simple filaments (involucre) en- 

 folding numerous clustered seeds imbedded in a mucus. Con- 

 fer va^^corall'ma, E. B. t. 1815. Llghtf. p. 9S8. 



Hab. On the western coast in deep waters, sometimes dragged up in 



fishing-nets, or cast upon the shore in storms. Light/. 

 Turns whitish or greenish brown in drying. 



2. Gr. equisefifulia, red branched cylindrical, branches clothed 

 with short whorlcd imbricated forked jointed filaments whose 

 articulations are four times as long as they are broad and a lit- 

 tle thickened upwards. Conferva equhetfolia, Lightf. p. 984. 

 E.B. t. 1479. 



Hab. Firth of Forth, but rare, Mr. Yalden. 



In the crowded and whorled disposition of the branches it would ap- 

 pear, at first sight, to have considerable affinity with Cladostephus 

 spongiosus and \rrticillatus ; but the structure of the articulations is 

 ver)^ different. 



15. CERAMIUM. 



Fructification : Capsules. Filaments composed of simple tubes. 

 * Reddish. Capsules suhinvolucrate. 



1. C. rulrum, filaments dichotomous very much branched sub- 



• cartilaginous, branchlets forked, articulations opaque towards 

 the joints which are contracted, capsules globose lateral invo- 



a This truly beautiful genus is named l)y Agardh in honour of Mrs. Grif- 

 fiths of Torquay, Devon'shire, to whom the marine botany of this country 

 is under the greatest obligations, and who has contributed so largely to the 

 Historia Fucoricm of Mr. Turner. This lady is paying particular attention 

 to the fructification of the Algce , and her discoveries will, I am confident, 

 throw new light upon this tribe of plants. 



