196 BTK0PSI8 OF I3IUTISTT SEAWEEDS. 



Hab. On marine rocks, between tide-marks; also on Fu 

 ing timber, etc. Annual Summer. 

 This ami the following species, while they are evidently 



closely allied to each other, differ in some degree from the 

 true Tiyngby<Bi approaching nearer to Agardh's genus 

 SpJueroplea. There i3 a more distinct cellular division in 

 the tube than is typical of the genus with which they are 

 associated, and perhaps at a future time they may be re- 

 moved. But the whole group requires revision, and de- 

 serves more attention than it has yet obtained. The pre- 

 sent species I believe to be common to many parts of the 

 British coast, but is perhaps often confounded with Con- 

 ferva tortuosa, which it much resembles in habit and ge- 

 neral aspect. 



368. speciosa {The beautiful Lyngbya) ; filaments long, thick, 

 flaccid, straight, at length curled, the margin crenate, form- 

 ing bright yellow-green strata, glossy when dry ; tube im- 

 perfectly jointed, Carmichael, Alg. Appin. ined. (Atlas, 

 PL LXXVIIL Fig. 369.) 



Hab. On marine rocks, between tide-marks, and on Fuel. An- 

 nual. Summer. 

 This very pretty species is chiefly distinguished from 

 the preceding by its larger size, brighter colour, and more 

 lubricous substance. It adheres far more closely to paper 

 in drying, and does not so perfectly recover its form after 

 having once been dried. 



369. flacca {The soft Lyngbya); filaments short, tufted, straight 

 or gently curved, simple, or having a few slender, proliferous, 

 subulate, root-like ramuli, articulated ; articulations shorter 

 than their diameter, the endochrome at length contracting 

 into a small central sporidium, Harv. in Phyc. Brit, list, v. I. 

 p. 15. (Atlas, PL LXXVI. Fig. 359.) 



Hormidium flaccum, Ktz. Hormotrichum flaccum, Ktz. Con- 

 ferva flacca, Dilfoo. 

 Hab. Parasitical on various small Algae in tide-pools ; on the Fuci, 

 and growing also on floating timber. Annual. Summer. Xot 

 uncommon. 

 In the last edition of my ' Manual' I have divided the 

 genus Lyngbya into two sections, to the latter of which 

 the species now described belongs, as well as the two 

 preceding species, L. Carmichaelii and L. sjoeciosa. A 

 better course would probably have been to have adopted 

 Kiitzing's genus Hormotrichum for this latter group, 

 adding to it, as that author has done, Conferva ban- 



