206 RHIZOCLONIUM. 



The bottoms of clear rock-pools, near low-water mark. Annual. Sum- 

 mer. Rocks outside Dingle Harbour, Kerry, W. H. H. Jersey, Miss 

 White. Filaments densely tufted, 3 or 4 inches long-, thicker than human 

 hair, nearly equal throughout, much branched ; the branches curved and 

 twisted, the lesser divisions and ramuli frequently incurved, arching or 

 strongly hooked inwards ; the whole plant crisp and squarrose. Colour a 

 peculiarly rich, glossy green. Substance rigid, adhering to paper in dry- 

 ing. I was not aware, at the time I published this plant in Phyc. Brit. 

 that it had already appeared, and oddly enough, under the same specific 

 name, in the Botanicum Gallicon. I am indebted to my friend Dr. Mon- 

 tague for ascertaining the above synonyme of Duby. 



Species found in brackish water. 



21. C. flavescens, Roth; forming pale yellowish strata; 

 filaments slender, sparingly branched; branches alternate or 

 sub-dichotomous, erecto-patent, with scattered, elongate, al- 

 ternate or secund ramuli ; articulations 8 or 9 times longer 

 than broad. Harv. 1. c. p. 356 ; E. Bot. t. 2088 ; Wijatt, 

 Alg. Danm. No. 224. 



In ditches of brackish or fresh water, not uncommon. This forms ex- 

 tensive strata of a light yellowish colour, which finally rise to the surface. 

 It is allied to C. fracta, but the filaments are more slender, the joints 

 longer, and the colour is different. It has a silky appearance when dry, 

 and does not adhere to paper. 



22. C. fracta, Fl. Dan. ; forming entangled, dull green 

 strata; filaments somewhat rigid, much branched ; branches 

 divaricating; ramuli scattered and very patent; articulations 

 46 times longer than broad. Dillw. Conf. t. 14 ; E. Bot. 

 t. 2338; Harv. I c. p. 356. 



In ditches, lakes, &c. common. This forms globose or long entangled 

 tufts, frequently cohering into extensive strata, and finally rising to the 

 surface. The filaments are much and very irregularly branched, all the 

 branches very patent. 



II. RHIZOCLONIUM. Ktttz. [Plate 24, F.] 



Filaments green, jointed, uniform, decumbent, simple or 

 spuriously branched ; branches short and root-like. Fruit : 

 granules contained in the cells. Name, from ptfou, to root, 

 and KXWV, a branch. 



1. R. riparia, Roth ; filaments elongated, slender, de- 

 cumbent ; pale green, forming wide strata, flaccid, entangled, 

 angulato-flexuous, slightly branched ; lower branches short, 

 tentacular ; tipper long, sub-simple, with rounded axils ; arti- 

 culations 2 4 times longer than broad. E. Bot. t. 2100 ; 



