288 



POPULAR HISTORY OF LICHENS. 



layer, greyish, becoming brown ; internally solid, white, stupose. 

 Apothecium spherical, the bluish-black spores accumulating on 

 the surface of the thalamium as a soot-like powder.* Thalamium 

 internally floccose-cartilaginous. 



1. Spblerophoron coralloides. Thallus brownish, 

 waxy, smoothish, terete or somewhat compressed ; ultimate 

 ramules having an obtuse, but not swollen, apex. Apothecia 

 erect, globose ; margin often inflexed. Spores roundish or 

 oblong. The thallus is either loosely and irregularly branched 

 or it is csespitose, fastigiate, and dichotomously branched. 

 (E. B. 115, var. laxum.) 



Common on rocks in Highland districts. The blackish 

 or indigo-coloured dust which covers the thalamium is 

 found to consist, under the microscope, of the spores, mixed 

 with a quantity of blackish or bluish-black granular debris. 

 Leighton describes the spores as hyaline and double-walled, 

 and ascribes their black colour and irregular granulated 

 form to their contents, w 7 hich are blackish or bluish-black 

 granules, and which, when they escape, adhere to the exte- 

 rior of the mother-cell. Tulasne speaks of the epispore as 



* Tor observations on the structure of the Apothecia, vide Camille Mon- 

 tague in ' Ann. des Sciences Naturelles/ vol. xv. p. 147, or c Anuals of Natural 

 History,' vol. x. 267. 



