The Scottish Naturalist. 119 



the larger proportion of the ground is still in a natural, uncul- 

 tivated state. Above all there are no collieries or chemical 

 factories, the gases from which, especially acid gases, are so 

 destructive of lichens. 



The group which is best developed is that clustered around 

 Cladonia squamosa \ and it is remarkable that the forms belonging 

 to both CI. squamosa and CI. sub squamosa are nearly equally 

 represented. Perhaps those under the latter species are the 

 more luxuriant and varied. Of CI. subsquamosa I possess 24 

 specimens, in all of which, and at all stages of growth, the reac- 

 tions Ky, C — are remarkably distinct and vivid. The yellow 

 reaction by K is instantaneous and permanent. This yellow 

 reaction in a certain proportion ultimately merges to a fixed red 

 or ferrugineous red. Of this after reaction I have hitherto 

 taken no account in the discrimination of Cladonise. 



In several instances, the corresponding forms of CI. squamosa 

 and subquamosa grow closely associated and even intermingled, 

 while, in such instances, there is not the slightest trace of 

 yellow produced by K on the specimens of the former lichen. 



Taking as my basis Prof. Th. Fries's diagnoses of CI. squamosa 

 and its allies as given on pp. 75 and 76 Lich. Scand. (1872), I 

 propose to distinguish the corresponding forms of CI. subsquamosa. 

 It is remarkable that Fries had not, at the date of the publication 

 of his work, seen any of the forms of CI. subsquamosa. His 

 words are, "Thallum reagentiis solitis numquam vidimus tinctum." 

 Whether he has since detected any I am not aware. 



First as regards the form allied to C. asperella (Flk.). This is 

 beautifully represented in Mr. M 'Andrew's collection, is in fine 

 condition and, for the most, covered with apothecia. 



CI. subsquamosa (Nyl.) * furfur os a (Strn). Similis CI. aspereltce 

 (Flk.) sed thallo Kn\, C — . Apothecia cymoso-conferta, juniora 

 pallide fuscescentia, plana, marginata, dein convexiuscula, fusco- 

 nigra et saepe medio pertusa. Phyllocladia basalia, pauca vel 

 interdum nulla visibilia (Coll. M 'Andrew No 1). 



CI. subsquamosa * dilatata (Strn.). 



Podetia sursum incrassata, laevigata, sed phyllocladiis laciniatis 

 sparse vestita, hinc inde lacunose impressa vel-foveolata, simplicia 

 vel superne fastigiato-ramosa. Phyllocladia basalia crenato- 

 incisa. Th. Kfl. C— . 



