370 ECOLOGY 



Cladonia cocci/era. Peltigera malacea. 



Cladonia pyxidata. Peltigera canhia. 



Cladonia fimbriata. Peltigera aphthosa. 



e. On peaty soil. Peat is generally found in most abundance in 

 northern and upland regions, and is characteristic of mountain and moor- 

 land, though there are great moss-lands, barely above sea-level, even in our 

 own country. Such soil is of an acid nature and attracts a special type of 

 plant life. The lichens form no inconsiderable part of the flora, the most 

 frequent species being members of the Cladoniaceae. 



The principal crustaceous species on bare peaty soil in the British Isles 

 are Lecidea uliginosa and L. granulosa. The former is not easily distinguish- 

 able from the soil as both thallus and apothecia are brownish black. The 

 latter, which is often associated with it, has a lighter coloured thallus and 

 apothecia that change from brick-red to dark brown or black ; Wheldon 

 and Wilson 1 remarked that after the burning of the heath it was the first 

 vegetation to appear and covered large spaces with its grey thallus. Another 

 peat species is Icmadophila ericetorum, but it prefers damper localities than 

 the two Lecideae. 



To quote again from Arnold^: 24 species were found on turf around 

 Munich, 13 of which were Cladoniae, but only four species could be con- 

 sidered as exclusively peat-lichens. These were: 



Cladonia Floerkeana. Thelocarpon turficohtm. 



Biatora terricola. Geisleria sychnogonioides. 



The last is a very rare lichen in Central Europe and is generally found 

 on sandy soil. Arnold considered that near Munich, for various reasons, 

 there was a very poor representation of turf-lichens. 



/ On mosses. Very many lichens grow along with or over mosses, 

 either on the ground, on rocks or on the bark of trees, doubtless owing to 

 the moisture accumulated and retained by these plants. Besides Cladoniae 

 the commonest " moss " species in the British Isles are Bilimbia sabulosa, 

 Bacidia muscorum, Rinodina Conradi, Lecidea sanguineoatra, Pannaria 

 brunnea, Psoroma hypnorunt and Lecanora tartarea, with species of Collema 

 and Leptogium and Diploschistes bryophilus. 



Wheldon and Wilson^ have listed the lichens that they found in Perth- 

 shire on subalpine heath lands, on the ground, or on banks amongst mosses: 



Leptogmin spp. Lecidea granulosa. 



Peltigera spp. Lecidea uliginosa. 



Cetraria spp. Lecidea neglecta. 



Parmelia physodes. Bilimbia sabulosa. 



Psoroma hypnorum. Bilimbia ligniaria. 



Lecanora epibryon. Bilimbia melaena. 



Lecanora tartarea. Baeomyces spp. 



Lecidea coarctata. Cladonia spp. 



1 Wheldon and Wilson 1907. '^ Arnold 1892, p. 34. ' Wheldon and Wilson rpis. 



