Bd. IV: ii) THE LICHENS. 7 



sporae septenae aut normaliter octonae, hyalinae, unicellulares, 4 /< limbatae, 50—60 

 X25 — 30 /a magnae, quasi biseriatim dispositae; asci soli jodo coerulescentes; spermo- 

 gonia et soralia nulla visa; habitat ad saxa, Falkland Islands, Port Stanley. 



Notes: The thallus of this species is very thick, as much as 2 mm in places 

 and yet it shows no clear and distinct areolation. The latter as far as it occurs is 

 mainly superficial and the chinks are often not continuous enough to break up the 

 thallus into a number of aréoles completely. The apothecia are comparatively speak- 

 ing small and included in the thallus. The thallus is of a light greyish colour and 

 s thus not easily distinguished from the similarly coloured substratum. 



Pertusaria alterimosa nov. spec. 



(Plate I, fig. II.) 



Thallus ad 2 mm latus, cartilagineus, rugoso-inaequalis et profunde et regulariter 

 rimoso-diffractus, pallide flavescenti-albicans, hypothallus liber non visus sed alios 

 Hellenes Lecideae speciei tangens lineam distincte nigram faciens; tubercula fertilia 

 ad 2 — 3 mm lata, apothecia continentia 1 — 3; ostiola ad 1.5 magna; gonidia proto- 

 coccoidea; K primo flavescens et deinde intense ferrugineo-rubescens; epithecium 

 thallo subconcolor aut parce obscurior; asci soli jodo caerulescens; sporae hyalinae, 

 unicellulares, vulgo 2 — 3:nae et dein 100 — 150x50 — 60// magnae aut rarius solitariae 

 et dein 166x70 /< magnae; paraphyses 1 ;< latae; spermogonia contorta; sterigmata 

 simplicia; spermatia recta, 1 x 5 (.1 magnae; soralia non visa; habitat ad saxa, Falk- 

 land Islands, Port Louis. 



Notes: In this species as distinct from the previous one the chinks are deep 

 and very distinct, breaking up the thallus into very regular aréoles. 



Pertusaria solitaria nov. spec. 



(Plate 1, fig. 12.) 



Thallus lactis flori concolor, tenuis aut crassiusculus, minute sed profunde rimoso- 

 diffractus, K flavescens et dein sanguineo-rubescens; hypothallus nullus distinctus sed 

 margo thalli tenuissimus et paulo pallidior; apothecia solitaria, tuberculis immersa, 

 difformia, 0.5 — 1.0 mm lata; epithecium obscure rufescens sed distincte pruinosum; 

 parathecium et hypothecium decolor; paraphyses ramosae, 2 — 2.5 mm latae; sporae 

 octonae, polyseriatim dispositae, hyalinae, unicellulares, 40 — 50x22 — 30 fi magnae; 

 paries sporarum ad 2 /< crassus; spermogonia et soralia non visa; habitat ad saxa, 

 Falkland Islands, Port Louis. 



Notes: The distinguishing features of this species are the solitary apothecia and 

 the clear pruinose condition of the epithecium. The thallus, as in the previous new 

 species is thick and very deeply rimose but the thallus as a whole is not so thick. 



