366 ALGM CONFERVCIDE.E. .Calothrix. 



elongating into branches. Can this be the origin of the oppositional 

 branches of the Calothrices? — Conferva mirabilis ; E. Bot. t. 2219, (not 

 of Dillw.) which Agardh in his last work makes a variety of Sphacelaria 

 cirrhosa, I can refer with confidence to the present, having examined 

 Miss Hutchins' specimens, from which Sowerby's figure was taken. 

 Much confusion has arisen by Sir J. E/ Smith's stating, that the plant 

 was gathered " in Bantry bay," instead of " near Bantry." The speci- 

 mens are parasitical on an Orthot/ichum (probably O. rivulare), and 

 their fresh-water locality is thus clearly proved. 



5. S. cirrhosum, Carm. (tufted Scytonema); "tufts widely 

 spreading, filaments floating in bundles spuriously" (?) " branch- 

 ed, branches beset with fragments towards the top." Carm. 



MSS. cum ic. 



Borders of lakes at Lismore island, Capt. Carmichael. — '« It occurs in 

 continuous fleeces, parallel to the water's edge, of a deep chestnut 

 colour when lying flat, dark-olive when floating. The fleeces are made 

 up of small contiguous fasciculi of interlaced filaments. The filaments 

 are from half an inch to an inch in length, simple or spuriously (?) branch- 

 ed, and prolonged by the successive adhesion of portions, seemingly of 

 broken filaments, which at length coalesce and form a knot at the point 

 of adhesion. The transverse spires are close and conspicuous." Carm. 

 MSS. I rather suspect that what Carmichael terms spurious branches, 

 have the same origin as the branches of S. myochrous, of which this 

 species is perhaps a variety, though the habit is very different. - 



6. S. contextum, Carm. (interwoven Scytonema); " filaments 

 mostly simple interwoven into a tough olivaceous stratum which 

 turns to a dull-green in drying." Carm. MSS. 



On the moist earth, Appin, Capt. Carmichael. Rocks at the foot of Turk 

 Mountain, Killarney, IV. H. Harvey. — " This species occurs in a thin, 

 closely-matted, blackish fleece, of indeterminate extent. Filaments 2 — 3 

 lines in length, simple or rarely furnished with one or two branches," 

 (which are occasionally geminate as in S. myochrous,) " interwoven into 

 an almost inextricable stratum. Sporidia, when visible, which rarely 

 happens, globular and rather distant. Besides the comparative short- 

 ness of the filaments, and the more intimate contexture of the stratum, 

 this species differs from S. myochrous in becoming, when dry, of a light 

 greyish-green colour, instead of black." Carm. MSS. 



7. S. byssoideum, Ag. (downy Scytonema); filaments minute 

 erect simple flexuose fasciculate forming an unequal blackish 

 crust. — Ag. Syst. Alg. p. 39. 



On the trunk of a living Elm, at Oundle, Northampton, Rev. M. S. 

 Berkeley. — This forms a very thin, effused, blackish, velvetty crust. Fila- 

 ments exceedingly short, olivaceous, equal, very obtuse, erect, flexuose, 

 often joined together laterally into little compressed tooth-like fascicles. 

 Annuli close and evident. 



73. Calothrix. Ag. Calothrix. 



Filaments destitute of a mucous layer, erect, tufted or fascicu- 

 late, fixed at the base, somewhat rigid, without oscillation. Tube 

 continuous ; endoclirome green, densely annulated, at length dis- 



