GOXIONEMA.] SIROSIPHEI. 19 



Ann. Mag. Nat. Hist. scr. 3, xvi. p. 8, t. 4. flP. 1-G ; Lich. Fl. p. 11, 

 ed. 3, p. d ; Cromb. Lich. Brit. p. 1. — Pohjchidium velntinum Gray, 

 Isai. AxT. i. p. 402 ; Lichen vehitinus Ach. Prudr. (1798) p. 218. 



The thallus is very densely matted together, and sometimes spreads 

 extensi\ely over the substratum. When young and infertile it is 

 with difficulty distinguished from some species of Scytonema. The 

 apothecia, which are reddish when young, seem to be very rare in this 

 country, nor are the spermofrones often met with ; they are nearly 

 turbinate, pale reddish, the spermatia beinof 0,002 mm. loiio-, 0,001 mm. 

 thick. 



Hab. On mica-schist rocks in mountainous districts. — Distr. Local 

 and scarce in North Wales, and among the Grampians, Scotland ; no 

 doubt often overluoked elsewhere. — B. M. : Near Barmouth and Cader 

 Idris, Merionethshire ; Craig Breidden, Montgomeryshire. Ben Cruachan, 

 Argyleshire ; Ben I.awers and Craig Tulloch, Perthshii-e ; Glen Callater, 

 Braemar, Aberdeenshire. 



2. G. compactum Nyl. Flora, 1883, p. 104.— Thallus thinly 

 filamcntose, dark-brown, filaments ascending and crowded, forming 

 a snbascending tomentum. Apothecia globulose, reddish, the 

 epithecium rather indistinct : spores oblong, 0,010-0,015 mm. long, 

 0,006-0,008 mm. thick. — Cromb. Journ. Bot. 1885, p. 195. — 

 Scytonema compactum Ag. Disp. Alg. (1812) p. 39: Sm. Eng. Fl. 

 V. p. 364. HassalUa compacta Hass. Br. Freshw. Alg. p. 232, 

 t. 68. f, 3. Sirosiphon compactus Ktz., Leight. Lich. Fl. ed. 3, 

 p. 9. 



The recent discovery of the fructification in N.W. England has defi- 

 nitely placed this plant among Lichens. It differs from the preceding in 

 the filaments, which are often curved, being more erect and branched 

 towards the apices, and in the ajjothecia being globular, with the epi- 

 thecium less distinct and the spores somewhat larger. The spermogones 

 are globoso-adnate, with spermatia thin, 0,001 mm. long, 0,005 mm. 

 thick. 



Hab. On moist rocks in upland and subalpine districts. — Dist)-. Pro- 

 bably not unfrequent, though seen only from N. Wales, N.W. England, 

 S. and Central Scotland, and N.W. Ireland. — B. M. : Lyn Aran, Uorgelly, 

 Merionethshire; Mardale, Westmoreland (frt.); Wastdale Lake, Cuni- 

 berland ; Ben Lawers, Perthshire. Near Kylemore Lake, co. Galway. 



2. SPILONEMA Born. Mem. Soc. Cherb. iv. (1856) p. 226; 

 Nyl. Syu. i. p. 89. — Thallus minute, fruticulose, often pulvinate ; 

 gonimia 2 or 3, or several together, arranged in more or less regular 

 series throughout the rounded thallus. Apothecia small, lecideijie, 

 lenticular ; spores simple or 1-septate, paraphyses thickish, arti- 

 culate : hymenial gelatine bluish with iodine. Spermogones 

 tuberculose, with jointed sterigmata, spermatia shortly cylindrical. 



This differs from Gonionema chiefly in the characters of the gonimia, 

 paraphyses, and sterigmata. Some plants agi'eeing in the structure of 

 the thallus and the apothecia with Spilonema, but the spermogones of 

 which have not been detected, may also, for the present, be refeiTed here, 

 though eventually they may be found to belong to Sirosiphon {vide Cromb. 



c 2 



