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POPULAR HISTORY OP LICHENS. 



Thallus squamulose ; squamules often aggregated into 

 a variously plicate crust. 

 a. Squamules solitary or imbricate. 



1. Lecidea decipiens. Thallus brick-coloured, below and 

 at margins white; squamules orbicular or sinuate-lobate, 

 wavy, discrete or aggregate. Apothecia black within and 

 without, globose, marginal. As the plant becomes old the 

 thallus and apothecia sometimes become white. 



On heathy or gravelly soil in different parts of Scotland 

 and England ; not very common. Its spermogones are not 

 abundant, but are easily recognized, when they are present, 

 on the centre of the squamules, by their minute stellate 

 pores. They are immersed, globular, divided interiorly into 

 several plicate sinuses; their sterigmata are linear, very 

 slender and crowded ; their spermatia numerous and straight. 



b. Squamules aggregated into a gyrose or rugose-plaited 

 crust. 



2. Lecidea oeruleo-nigricans (eceruleus, blue or green, 

 and nigricans, blackish) . Thallus blackish-green, often whit- 

 ish or greyish-pruinose, cartilaginous ; squamules aggregated 

 into a bullate or rugose-plicate crust. Apothecia black with- 

 out, white within, naked ; margin prominent, often flexuose. 

 The thallus usually sends upwards erectish, stem-like, ramose 



