CLADOPHORA. 205 



Dillw. t. E. ; E. Bot. t. 2098 ; Har-v. 1. c. p. 359. C. centra- 

 Its, Lyngb., Harv. I. c. p. 358 ; Wyatt, Alg. Danrn. No. 46; 

 Harv. Phyc. Brit. t. cxxxv. 



On rocks in the sea, generally above half-tide level, frequent. Tufts 

 rising from a broad disk formed of dense fibres. Filaments spreading in 

 a circle, fastigiate, much branched : in the young specimens the branches 

 are somewhat separate, all remarkably erect or straight (when it is C. arcta 

 of Dillwyn and of ' Brit. Flora,' and in a still younger state C. vaucheria- 

 formis of Agardh) ; in the older they are more or less matted together or 

 interwoven by means of rootlike fibres which issue from the joints of the 

 main branches, the apices only, in these specimens, produced beyond the 

 spongy tuft, long, slender, straight, of irregular length and slightly branch- 

 ed ; all the rarnuli extremely erect and close-pressed (forming the C. cen- 

 tralis of Lyngbye and of ' Brit. Flora'). Joints extremely variable, some- 

 times uniformly twice as long as broad throughout, but more frequently 

 the lower joints are short, those of the upper branches very long. Colour 

 a fine, deep, glaucous green, partially discharged in fresh water or fading in 

 the herbarium. Substance soft and retaining water. Tn the dry state 

 young specimens have a glistening appearance ; old ones, on the contrary, 

 are without gloss, except the young shoots toward the summit, woolly, and 

 considerably faded. In the ' Brit. Flora' I expressed my doubts whether 

 C. arcta and centralis of authors, however dissimilar in their typical states, 

 were really distinct. Since then, numerous specimens in every stage, from 

 the extreme young to the old and battered form, kindly furnished by Mrs. 

 Griffiths, have clearly shown such a giadation of character, that I no 

 longer hesitate to unite them. 



19. C. glaucescem, Griff. ; tufts dense, glaucous green, 

 sub-fasti gi ate ; filaments very slender, excessively branched ; 

 branches straight and erect, the lesser ones furnished with 

 close, very erect, straight, elongated ramuli ; joints very 

 short. Wyatt, Alg. Danm. No. 195 ; Harv. Phyc. Brit, 

 t. cxcvi. 



On rocks, near low-water mark, not uncommon. Tufts 2 or 3 inches 

 high, dense, somewhat level-topped, of a glaucous green colour. Fila- 

 ments very slender (but more robust than in C. refracla), much branched 

 upwards, the branches straight and erect, the lesser ones furnished with 

 close, very erect and appressed, elongated, straight, setaceous ramuli. 

 Joints thrice as long as broad. Colour preserved in drying. 



20. C. falcata, Duby ; densely tufted, dark green ; fila- 

 ments intricate at the base, ultra-capillary, rigid, much curved, 

 irregularly branched ; branches zig-zag, repeatedly divided, 

 the lesser divisions arched, or strongly incurved and falcate, 

 furnished along their inner faces with short, secund, blunt 

 ramuli ; articulations three or four times longer than broad, 

 with a dense endochrome, and pellucid dissepiments. Harv. 

 Phyc. Brit. t. ccxvi. Conf. falcata, Duby, Bot. Gal. fide 

 Montagne. 



