SCLERODERRIS. 251 



Scleroderris fuliginosa (Fries). (Britain and U.S. America.) 

 This was considered to be a saprophyte till my attention was 

 directed to its injurious nature. It occurs on living branches 

 of Salix Caprea, S. triandra, S. alba, etc., and brings about 

 their death. The black crusts, on which the apothecia develop, 

 appear both on weakly twigs and strong branches. The my- 

 celium makes its way through the tissues to the cambium, which 

 it kills, causing this and neighbouring parts to become brown. 

 Adjacent parts, as yet unattacked, continue at first to grow in 

 thickness, but they too are gradually killed. As a result, the 

 twigs attacked grow irregularly according to the extent and 

 number of diseased places (Fig. 134); and when all or most 

 of the lower tissues of a twig are killed, the higher parts 

 die off with their leaves. Wherever the fungus appears, many 

 trees are generally attacked. 



Sc. aggregata (Lasch.) develops ou the liviug stems of Rhinaiithaceae 

 and matures on the dead. 



Sc. ribesia (Pers.) is a common species on twigs of red and black currant, 

 but whether parasitic or not is unknown. 



(2) DERMATEACEAE. 



The apothecia are developed at first either under the sub- 

 stratum or altogether superficially. The ascogenous layer 

 extends over a thick hypothecium. 



The Dermateaceae contain the Genangieae, Dermateae, Patel- 

 lariaceae, and Bulgariaceas. 



CENANGIEAE. 



Apothecia at first embedded, then exposed. They are sessile, 

 clavate or cone-shaped, and broaden out to discs on opening. 



Genangium. 



Apothecia globose ; on dehiscence at first cup-shaped, but 

 afterwards flatter and more saucer-shaped, with entire margins; 

 they may occur singly or massed together. The club-shaped 

 asci contain eight colourless, oblong, unicellular spores, and 

 filamentous paraphyses with thickened apices. 



Cenangium abietis (Pers.). (Britain and U.S. America.) This 

 fungus is usually a saprophyte, but Thiimen suggests it as an 



