GONIONEJIA.] S1KOSIPHEI. 19 



Ann. Mag. Nat. Hist. ser. 3, xvi. p. 8, t. 4. ff. 1-6 ; Lich. Fl. p. 11, 

 ed. 3, p. 9 ; Cromb. Lich. Brit. p. 1. Polychidium velutinum Gray, 

 Nat. Arr. i. p. 402 ; Lichen velutinus Ach. Prodr. (1798) p. 218. 



The thallus is very densely matted together, and sometimes spreads 

 extensively 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 spermoffones often met with ; they are nearly 

 turbinate, pale reddish, the spermatia being 0,002 mm. long, 0,001 mm. 

 thick. 



Hob. On mica-schist rocks in mountainous districts. Distr. Local 

 and scai'ce in North Wales, and among the Grampians, Scotland ; no 

 doubt often overlooked elsewhere. B. M. : Near Barmouth and Cader 

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

 Argyleshire ; Ben Lawers and Craig Tulloch, Perthshire ; Glen Callater, 

 Braemar, Aberdeenshire. 



2. G. compaction Nyl. Flora, 1883, p. 104. Thallus thinly 

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

 a subascending 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. M. 

 v. p. 364. Hassattia 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 apothecia 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. 



Hob. On moist rocks in upland and subalpine districts. Distr. Pro- 

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

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

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

 berland ; Ben Lawers, Perthshire. Near Kylemore Lake, co. Gal way. 



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

 Nyl. Syn. 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, lecideinc, 

 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 agreeing 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 referred here, 

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



c 2 



