202 



POPULAR HISTORY OF LICHENS. 



growing on old walls about Moffatt, Dumfries-shire. Its 

 thallus frequently becomes the seat of a sorediiferous, furfu- 

 raceous, or isidioid efflorescence; in such states we have 

 found it on Kinnoull Hill and elsewhere round Perth. Its 

 spermogones are the black points scattered frequently over 

 the thallus ; they are globular, very minute, with a simple 

 cavity ; the spermatia are straight and very numerous. 



11. Parmelia olivacea (oliva, the olive). Thallus mem- 

 branaceous, deep olive-brown, smooth, rugulose, sometimes 

 furfuraceous or granulate-farinose — below paler or blackish, 

 roughened, smooth at circumference ; lacinise plicate, rotun- 

 date-lobate ; lobes appressed. Apothecia of similar colour 

 to thallus, or chestnut-coloured ; margin inflexed, at length 

 rugose or crenate. (E. B. 2180.) 



A common corticolous and saxicolous species on roadsides 

 and the outskirts of woods in lowland districts. On trees, 

 such as the oak and ash, it is usually fertile; on stones 

 and rocks it is generally degenerate and sterile. Its thecse 

 are short, small, ovoid, and eight-spored ; the spores small, 

 roundish, colourless, double-walled, resembling those of Cor- 

 nicularia ; the paraphyses are very delicate. 



1 2. Parmelia Pahlunensis (Fahlun, a Swedish mining 

 village). Thallus subcartilaginous, smoothish, bronze or 



