Bd. IV: ii) THE LICHENS. 1 5 



Buellia melanotrichia nov. spec. 



(Plate 3, fig. 27.1 



Thallus tenuissimus, rimoso-areolatus, maculas formans minutas ad 5 mm latas; 

 areolae pallide fuscescentes hypothallo superimpositae bene distincte» aterrimo, ex 

 hyphis formato capillaribus, nigris, tenuissimis, emanentibus; hypothallus totus 1 — 1.5 

 mm latus; K — ; apothecia nigra, margine proprio circumdata non semper bene di- 

 stincto, disco piano aut parce convexo, 0.3 — 0.5 mm lata; epithecium, parathecium 

 et hypothecium nigro-fuscum aut carbonaceum: sporae octonae, pallide fuscescentes, 

 bicellulares, medio non constrictae, apicibus rotundatis, 28 — 32x8 — 12 /.i magnae; 

 spermogonia non visa; habitat ad lapillos, South Georgia, Cumberland Bay, Mo- 

 raine Fiord. 



Notes: This is again a very clearly marked species owing to the small but not 

 undeveloped thallus. The central portion consists of a few well marked aréoles of a 

 pale brownish colour which are considerably higher than the dark hypothallus which 

 forms a very characteristic feature of this .species. It is made up of fine thread-like 

 but flattened filaments which spread from the thicker areolate portion of the thallus. 

 The whole plant in any case is very small and it appears to be a rapid grower as 

 it occurs on small stones. 



Buellia Nelsonii nov. spec. 



(Plate 3, fig. 28). 



Thallus flavescens, irregulariter rimoso-diffractus, crassiusculus, bene evolutus, 

 maculas formans in paucis speciminibus visis ca. 10 mm latas, hypothallo instructus 

 nigerrimo ad 8 mm lato; K — ; apothecia bene elevata, et semper nigerrima, margine 

 proprio instructa semper distincto et disco piano dein convexo, diflbrmia aut saepius 

 confluentia, 0.4 — 0.7 mm lata; epithecium et parathecium carbonaceum; hypothecium 

 valde fuscescens; sporae octonae, bicellulares, fuscae, 18 — 20x8 — 9 11 magnae; medio 

 non constrictae, apicibus rotundatis; spermogonia non visa; habitat ad saxa, So it lit 

 Shetland Islands, Nelson Island. 



Notes: Here again the very marked hypothallus is an important and distin- 

 guishing feature. The black hypothallus is not only developed near to other neigh- 

 bouring lichens but it is best developed where it is not in contact with other plants 

 where it is free to grow at its own will. In one or two cases 4-celled spores were 

 found, though 2-celled ones were by far the commoner. The former measured 

 24—26x8 — 10 u. 



Buellia latemarginata nov. spec. 



(Plate 3, fig. 29t. 



Thallus sordide cinereo-fuscescens aut obscure fuscescens, crassiusculus, irregu- 

 lariter profunde rimoso-diffractus et areolatus, aut quasi squamoso-tuberculatus; hypo- 



