Sl'ILOXKMA.] SIR08IPHEI. 21 



while tbf monoecious fructification, the apothecia, and the spermogones 

 prevent all coufusion between them. The apothecia are rarely seen in British 

 specimens, though the spermogones are not unfrequent ; they are minute 

 black tubercules, with sterigmata 4-G-articiilate, spermatia '0,(X)2-0,002o 

 mm. long, 0,00")-0,001 mm. thick. 



Hah. On scliistose rocks in maritime and subalpine tracts. — Distr. 

 Local and scarce in X. Wales, and the S.W. Highlands of Scotland; 

 though no doubt it will b:' detected in other similar localities. — B. M. : 

 Barmouth, Merionethshire ; Barcaldine, Argyleshire. 



2. S. revertens Xyl. Flora, 180.5, p. 601. — Thallus effuse, mi- 

 nutely coralloideo-compact, in somewhat small, veiTUCulose pul- 

 viuuli, black or brownish-black. Apothecia lecideine, adnate, some- 

 what convex, imraarginate, black, dark-greyish within ; spores 

 oblong, simple, 0,008-0,011 mm. long, 0,005-6 mm. thick ; para- 

 pbyses thickish, incrassate and denigrate at the apices ; hymenial 

 gelatine bluish, the apices of the thecce deep-blue with iodine. — 

 Cromb. Journ. Bot. 1874, p. 331 : Leight. Lich. Fl. ed. 3, p. 11. 



In this species the pulviuuli are more or less crowded, and in a young 

 or poorly developed state are frequently somewhat discrete. Sirosiphan 

 saxirola Xaeg. in great part is apparently a sterile leprarioid condition 

 of this plant. In the only British specimen seen the apothecia are but 

 sparingly present. On the thallus of the same specimen pycnides are 

 also visible, which are minute, globose, immersed, colourless, with some- 

 what curved stylospores. 



Hab. On nioLst schistose rocks in subalpine districts.— D/^ir. Very 

 local and rare, at least in a mature condition, being known only from the 

 Central Grampians, Scotland. — B. M. : Craig TuUoch, Blair Athole, Perth- 

 shire. 



3. S. scoticum Xyl. Flora, 1869, p. 82. — Thallus effuse, mi- 

 nutely coralloid, in small, compact, verrucose, somewhat convex 

 pulvinuli. black or brownish-black. Apothecia minute, thinly 

 margined, black, epithecium impressed or slightly convex, vaguely 

 obscure, hypothccium colourless ; spores oviformi-oblong, 1-septate, 

 0,010-14 mm. long, o. 0045 mm. thick, paraphyses somewhat slender; 

 hymenial gelatine bluish, the thecfe violet with iodine. — Crorab. 

 Journ. Bot. 1869, p. 105 ; Lich. Brit. p. 1 ; Leight. Lich. Fl. 

 p. 12, ed. 3, p. IL 



The pulvinuli are usually discrete, though occasionally approximate, 

 on the crustaceous thalli, or the decayed mosses on which the plant 

 occurs. It is closely allied to the preceding, but is well distinguished by 

 the apothecia and the spores. The sterile thallus seems to be not un- 

 common ; but the apothecia are very rare. As in <S'. revertens, no sper- 

 mogones have yet been detected, so that both species are only temporarily 

 placed in Spilmiema. 



Hab. On mica-schist rocks, and on dead mosses (also on Sfereo- 

 caulon condeiisatiim) in subalpine tracts. — Disfr. Probably not un- 

 frequent in the mountainous districts of our Islands, though known only 

 from X. Wales, X. England, and the S. Grampians, Scotland. — B. M. : 

 Llvn Aran, iJolgelly, Merionethshire; Teesdale, Dm'ham; Ben Lawers 

 and Craig Calliach, Perthshire. 



