84 ACOTYLEDONS. ALG.^. Cerammm. 



rigid, generally olivaceous, scarcely jointed, truly torulose or 

 inflated at intervals, formed of a thickish membrane, whose 

 texture is evidently cellular. 



1. li.Jluviatilis, filaments subsimple olive-green torulose atte- 

 nuated, intervals between the swellings cylindrical much longer 

 than they are broad. Ag. p. 70. Conferva Jluviatilis, Dilliv. 



Co?if. t. 29. E. B. t. 1763. Lightf. 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. j 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. GR1FFITHS1A 3 . 

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



1. Gr. corall'ma, 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- 

 ferva corallina, E. B. t. 1815. Lightf. p. 988. 



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



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

 Turns whitish or greenish brown in drying. 



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

 with short whorled imbricated forked jointed filaments whose 

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

 tle thickened upwards. Conferva equisetifolia f 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 afiinity with Cladostephus 

 spongiosus and verticillatus , but the structure of the articulations is 

 very different. 



15. CERAMIUM. 



Fructification : Capsules. Filaments composed of simple tubes. 

 * Reddish. Capsules subinvolucrate. 



l.C. rulirum, filaments dichotomous very much branched sub- 

 cartilaginous, branchlets forked, articulations opaque towards 

 the joints which are contracted, capsules globose lateral invo- 



* This truly beautiful genus is named by Agardh in honour of Mrs. Giif- 

 fiths of Torquay, Devonshire, to whom the marine botany of this country 

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

 Hittoria Fucorum 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* 



