SCYTONEMES. 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. 
Sirosiphon pulvinatus, Breb. in Kutz. Spec. 317 (1849). 
Rabh. Alg. Eur. ii., 290. 
Hassallia turfosa, Hass. Alg. p. 232 (1845). 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.” 
“Tt is,” he says, ‘‘a true Scytonema.” As far as we have been enabled 
to trace it, it seems to be the same as the Strosiphon pulvinatus of 
Brebisson. The specific name of turfaceum has undoubted priority. 
Plate CX1. 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. 
Sizz. Trichomes ‘018--02 mm. 
Sirosiphon saxicola (Nag.). Johnson in Grevillea xii., p. 
76. Fischer Nost. fig. 13. 
On damp rocks, or rocks down which water trickles. 
Plate CX1. fig. 1. Abbreviated trichomes X 400, seldom exceeding 
this in size. 
Stigonema minutum. Hass. Alg. 230, t. 67, f. 3, 4. 
Spreading in a black suborbicular crust, or scattered in little 
tufts. Trichomes minute, erect, rigid, flexuous, fastigiate 
branches short, obtuse, sheath rather broad, fuscous; cells 
usually in a single series. 
Sizz. Trichomes :02-:03 mm. 
Scytonema 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 Kew 
Herbarium. 
Plate OX. fiy.1. Portion of trichome, nearly complete, X 400 diam, 
29 
