272 NEMATOGENA, 
in a double series, sheaths narrow, brown or yellow brown, paler 
at the tips or almost colourless. 
Size. Trichomes ‘035-05 mm. 
Eng. Fl. v., 863. Hass. Alg. 229, t. 66, f. 4, 5. Harv. 
Man. 153. 
Sirosiphon panniformis, Kutz. Tab. Phye. ii., t. 36, f. 2. 
Scytonema panniforme, Ag. Syst. p. 39. 
On rocks, stones, &c. ° 
Plate CX. fig. 4. Portion of trichomes X 400 diam. 
Stigonema mamillosum. (4g.) Kutz. Tab. Phyc. 11., t. 37, f. 4. 
Forming continuous tufts several inches in diameter, branches 
simple, their diameter being greatest in the middle, and beset 
on all sides with mamille of various sizes. 
Sizz. Trichome :06-:1 mm., very variable. 
Kirch, Alg. Schl. 229. Rabh. Alg. Eur. ii., 291. Eng. Fl. 
v., 363. Hass. Alg. 228, t. 66, f. 2, 3. Harv. Man. 153. 
Mack. Hib. 236, 
Rocky bottoms of sub-alpine rivulets. 
Plate CXI. fig.8. Portion of young trichome X 400, becoming more 
opaque with age. 
Stigonema compactum. Kirch. Alg. Schl. 230. 
Forming an expanded compact tomentose dark brown stratum, 
trichomes and branches ascending, a little attenuated at the 
apices, obtuse, internally formed of a single, rarely a double 
series of cells, which are torulose and almost moniliform, 
diameter and length nearly equal, filled with a pale blue-green 
granular plasma, sheaths firm, golden brown, heterocysts sub- 
globose or oblong. 
Size. Trichomes :015--016 mm. 
Sirosiphon compactus, Kutz. Tab. Phyc. ii, t. 36, f. 3. Rabh, 
Alg. Eur. ii., 287. Leight. Lich. Flora, p. 9. 
Hassallia compacta, Hass. Alg. 232, t. 68, f. 8. 
Scytonema compactum, Eng. Fl. v., 365. Harv. Man. 154. 
Grey. Ed. 302. 
On wet rocks. 
Plate CXI. fig. 4. Portions of trichomes X 400 diam. 
Stigonema turfaceum. (Berk. Eng. Bot. Supp. t. 2826, f. 1.) 
Pulvinate, deep olivaceous black, 2 lines thick. Trichomes 
very thick, much branched, golden yellow, becoming brownish, 
