246 CRYPTOGAMIA 



Hob. On rocks and algae, very common, in flaccid tufts 

 from 3 to 6 inches long, sometimes from the action of 

 the water interwoven and twisted into woolly cords. 



This species ascends our river for about half a mile, and in- 

 creases chiefly in the summer season. Adheres to paper 

 in drying. It is either very variable in colour and habit, 

 or there are some other species confounded with it. 



149. LEMANEA. 



1. L. flumatiliS) dull green; filaments elongate, straight, atte- 

 nuated, simple or sparingly branched, knotted ; knots formed of 

 3 obscure tubercles. HOOK. Scot. ii. 84. Conferva fluviatilis, 

 L.IGHTF. Scot. 985. DILLW. Con/, t. 29. Nodularia fluviatilis, 

 GREV. Fl Edin. 300. 



Hab. Rapid streams. In the Whiteadder about Ord-wheel, 

 attached to stones, plentiful. 



Grows in dense masses about 6 inches long. It is not lubri- 

 cous, rather rigid, and has something of the habit of a 

 Chara. 



150. DICTYOSIPHON. 



1. D. fceniculaceus, frond slender, olivaceous, much and irregu- 

 larly branched; branches alternate, capillary, attenuate at the 

 summits, spreading, covered with a fine filamentous fringe 

 GREV. Alg. Brit. 56. Conferva fceniculacea^ LIGHTF. Scot. 981. 

 Halymenia sublilis, HOOK. Scot. ii. 108. 



Hab. In rocky pools about the coves near Berwick, plenti- 

 ful. 



About a foot in length. I have a variety in which all the 

 branches are remarkably curled ; and another in which the 

 frond is jointed like a Ceramium. 



151. DUMONTIA. 



1. D. filiformis, frond dull red or purple, gelatinous, membra- 

 naceous, round, irregularly branched ; branches attenuate at the 

 base, elongate, nearly simple, erect, obtuse, straight or flexuose. 



