LECANORA.] LECANO-LECIDEEI. 427 



host of Arthonia variam (Dav.). The spermogones have the spermatia 

 arcuate, 0,022-23 mm. long, about 0,0005 mm. thick. 



Hub. On schistose, very rarely cretaceous, rocks in maritime districts. 

 Distr. Local in the Channel Islands, S.W. and N.W. England, Wales, 

 the S.W. Highlands and N.E. Scotland, S. and N.E. Ireland. B. M. : 

 Noirmont, Island of Jersey; Vale Bay, Island of Guernsey. Between 

 Porlock and Lvnton, Devonshire ; Penzance, Cornwall ; Manorheer, near 

 Tenby, Pembrokeshire ; Southerndown, Glamorganshire ; The Mowd- 

 doch and Barmouth, Merionethshire; Pwllheli, Carnarvonshire, Port 

 Soderick, Isle of Man. Loch Creran, Argyleshire ; Portlethen, Kincar- 

 dineshire. Kilkee, co. Clare ; Ardglass, co. Down. 



Form sublutior Nyl. Flora, 1882, p. 456. Thallus as in the 

 type. Apothecia pale-brownish. Cromb. Grevillea, xix. p. 60 

 (lapsu s. n. dilutior). 



Differs in the colour of the fruit, which probably arises from the habitat. 

 In the single British specimen the thalline margin of the apothecia is here 

 and there evanescent, so that they then appear biatoroid. 



Hab. On moist schistose rocks in a maritime district. Distr. Ex- 

 tremely rare in N.E. Scotland. B. M. : near Cove, Kincardineshire. 



109. L. prosechoidiza Nyl. Flora, 1881, p. 3. Thallus thin, 

 arcolabo-dift'ract, greyish (K , CaCl ). Apothecia moderate, 

 blackish or brownish-black, at first with entire whitish thalline 

 margin, at length convex and immarginate; spores ellipsoid, 0,009- 

 12 mm. long, 0,004-6 mm. thick; paraphyses rather coherent; 

 hymenial gelatine bluish and then (especially the thecae) violet or 

 subtawny with iodine. Cromb. Journ. Bot. 1885, p. 195. 



Approaches the preceding species, from which it differs more especially 

 in the less discrete paraphyses. Nylander, I. c., observes that it is 

 probably to be regarded only as a subspecies of L. umbrina ; but from 

 this it at once differs in the colour of the apothecia. In the single 

 British specimen the thallus is indeterminate and the apothecia are 

 numerous. The spermogones are only here and there visible, with 

 spermatia 0,016-22 mm. long, 0,0005 mm. thick. 



Hab. On schistose rocks in a maritime district. Distr. Extremely 

 local and scarce in N.E. Scotland. B. M. : near Portlethen, Kincardine- 

 shire. 



110. L. conferta Nyl. Ann. Sc. Nat. Bot. 1867, p. 314, nota 1. 

 Thallus effuse, thin, granulato-unequal, greyish-white or greenish- 

 grey, often obsolete (K , CaCl ). Apothecia small, plane, 

 crowded, subangulose, testaceous or pale-testaceous, with thin 

 crenulate thalline margin, or frequently subbiatorine ; spores 0,009 

 -15 mm. long, 0,0045-55 mm. thick; paraphyses submoderate, 

 brownish at the apices ; hymenial gelatine deep-bluish (the thecse 

 dark-violet) with iodine. Cromb. Grevillea, xviii. p. 69. Lecanora 

 umbrina var. conferta Cromb. Journ. Bot. 1870, p. 97. L. Hageni 

 var. conferta Leight. Lich. Fl. p. 208, ed. 3, p. 192. Patellaria 

 covferta' Dub. Bot. Gall. ii. (1830) p. 654. 



