SCYTONEME^E. 273 



variously curved, branches polymorphous, varying in thickness 

 according to age, obtusely rounded at the apex, cells in several 

 series, from 2 to 4 rows in the ramuli, sheaths thick, yellow 

 brown, hyaline. 



SIZE. Trichomes -025--03 mm. 



Sirosiplwn pulvinatus, Breb. in Kutz. Spec. 317 (1849). 

 Kabh. Alg. Eur. iL, 290. 



Hassallia turfosa, Hass. Alg. p. 232 (18-45). Kutz. Sp. p. 

 318. 



Scytonema turfaceum, Eng. Bot. ii., t. 2517, f. 1. 



Dematium turfaceum, Link. Spec, i., 134. 



On the ground in heathy places and on rocks. 



Berkeley says that this Alga was named by Klotsch as Dematium 

 turfaceum, Link., " which there is every reason to believe is correct." 

 "It is," he says, " a true Scytonema.'" As far as we have been enabled 

 to trace it. it seems to be the same as the Sirosipkon pulvinatus of 

 Brebisson. The specific name of turfaceum has undoubted priority. 



Plate CXI. fig. 2. Portions of trichomes X 400 diam. 



Stigonema saxicolum. (Nacg. in Kutz. Spec. 316.) 



Forming a thin dark olive velvety stratum. Trichomes 

 minute, curved, variously branched, closely crowded into a thin 

 dark crust or evenly scattered tufts ; sheath narrow, fuscous, 

 cells in a single series, growing denser and nucleate with age. 



SIZE. Trichomes -018-'02 min. 



Sirosiplwn saxicola (Nag.). Johnson in Grevillea xii., p. 

 76. Fischer Nost. fig. 13. 



On damp rocks, or rocks down which water trickles. 



Plate CXI. fig. 1. Abbreviated trichomes X 400, seldom exceeding 

 this in size. 



Stigonema minutum. Hass. Aly. 230, t. 67, f. 3, 4. 



Spreading in a black suborbicular crust, or scattered in little 

 tufts. Trichomes minute, erect, rigid, rlexuous, fastigiate 

 branches short, obtuse, sheath rather broad, fuscous ; cells 

 usually in a single series. 



SIZE. Trichomes '02- -03 mm. 



Scylonema minutum, Harv. Eng. Fl. v., 365. Harv. Man. 

 155. Mack. Hib. 236. 



On moist rocks in Alpine districts. 



Figured from the original specimen of the English Flora in the Kevv 

 Herbarium. 



Plate CX. Jiy. 1. Portion of trichome, nearly complete, X 400 diam, 



2 Q 



