144 



POPULAR, HISTORY OF LICHENS. 



as a formidable rival to the Ttoccellm. R. farinacea has also 

 been said to possess similar colorific properties. 



Genus IV. PHYSCIA, Schreh. 



Gen. Char. Thallus linear-laciniate, membranaceous; lower 

 surface of lacinise canaliculate, and differing in colour from upper 

 surface. Apothecium scutellate, subpedicellate, terminal or late- 

 ral. Thalamium always naked, varying in colour, and differing 

 in colour from the thallus. 



1. Physcia furfuracea {furfur, bran or scurf). Laci- 

 nise, — above greyish, furfuraceous (covered with a bran-like 

 dust), — below channeled, coal-black, reticulate-lacunose, — 

 becoming attenuated from a broadish base, loosely sinuate- 

 pinnatifid, naked at margins ; in old plants lacinise become 

 broadened and irregular, and are roughened with minute 

 granular isidioid or scale-like growths ; apothecium normally 

 terminal ; thalamium chestnut-coloured ; margin thin, entire. 



It grows on trees and rocks in subalpine woods, but is 

 not very common ; we have met with it frequently on firs 

 in the hill woods round Perth, but never in fructification. 

 We have seen large specimens, and in fine fruit, from Eothie- 

 murchus Woods, and from the Andes. It is found abun- 



