150 GUIDE TO THE STUDY OF LICHENS. 



9. Lecanora suhfusca. Thallus rudimentary to 

 warty or areolate, light-gray to light-brown. Apo- 

 thecia small to medium, margin entire and some- 

 what flexed, slightly elevated. Disk flattened to 

 convex, reddish-brown to black. Spores typical, 

 9/x X 6/t. 



It is perhaps likely that most authors combine several 

 species in the above. It is of common occurrence and 

 has a wide range. 



10. Lecanora atra. Thallus evenly spreading, be- 

 coming warty and areolate, gray. Apothecia medium, 

 margin slightly raised above the flattened black disk. 

 Spores typical, 12/x X 6/x. 



This lichen has been used in dyeing. 



11. Lecanora pallescens. Thallus rather thin, 

 more or less ridged or chinky, according to the 

 nature of the substratum (bark), surface smooth ; 

 pale-gray. Apothecia medium to large, margin some- 

 what rugose. Disk pale-brown. Spores large, typical, 

 SQfi, X 21/*. 



" This lichen yielded the * Orseille d'Auvergne.' 

 The pigment was prepared chiefly at St. Flour and 

 Limoges, and the lichen was collected by the peasantry 

 of Auvergne, Limousin, Languedoc, Provence, Lyons 

 and other districts of southern France. Manufacturers 

 distinguished two varieties, white and gray, depend- 

 ing chiefly on the maturity and purity of the plant, 

 the latter being preferred. Under the name of ' Light 

 Crottle ' it has been much used by the Scotch High- 

 landers to yield an orange or reddish dye for woollen 

 goods ; and as the common ' Crab's-eye Lichen * it 



