W. WEST AND G. S. WEST: ALGA-FLORA OF YORKSHIRE. 1 39 



Mid W.— Linn Gill. 

 N.W.— Cronkley Fell. 



683. Stigonema mamillosum (Lyngb., 1819) Ag. 1824. 

 N.W.— Cronkley Fell. 



684. Stigonema panniforme (Ag.) B. & F. 

 N.E. — Pilmoor, near Thirsk (vi. 1898). 



685. Stigonema informe Kiitz., 1849. 

 Mid W.— Ingleborough. 



N.W. — Cautley Spout ; very fine with Scytonema fnirabile. 



Family SCYTONEMACE^. 

 Genus MICR0CH.4iTE Thur., 1875. 



686. — Microchaete diplosiphon Gomont, 1885. 



N.E.— Strensall. 



Thickness of filament up to 14 ;«.; thickness of trichoma 

 5"5-6 ju. The outer sheath in these specimens was often irregu- 

 lar and attained rather wider proportions than in the original 

 French plants. 



Genus SCYTONEMA Ag., 1824. 



687. Scytonema Myochrous (Dillw., 1802) Ag. 181 2. 

 Mid W. — Ingleton. Cowside Beck, Arncliffe (very fine 



masses). 



N.W. —Cronkley Fell. Sedbergh. 



688. Scytonema mirabile (Dillw.) 



[Syn. S. figuratum Ag., 1824]. 

 N.W.— Cronkley Fell. Lund's Fell. Cautley Spout. 

 Mid W. — Linn Gill, on wet rocks. 



689. Scytonema alatum (Berk., 1833) Borzi, 1879. 



[Syn. Petalonema alatum Berk., 1833]. 

 Mid W. — Dripping rocks, Gordale. Linn Gill, on wet 

 limestone rocks. 



Genus TOLYPOTHRIX Kiitz., 1843. 



690. Tolypothrix distorta (Fl. Dan., 1780) Kiitz., 1843. 



[Syn. Plectoriema Kirchneri Cooke, 1882]. 



