210 FUNGOID PESTS OF CULTIVATED PLANTS. 



brown, and zoned. The spores almost globose and uncoloured, which 

 serves to distinguish it from the other species above named. 



Sacc. Syll. vi. 5412; Mas. PI. Dis. pp. 187, 393; Cooke, Hdbk. 

 No. 778 ; Sow. B. F. t. 132 ; Mass. Fun. FL i. p. 221 ; Hart. & Som. 

 Dis. Trees, p. 201. 



Fomes nigricans Fr. is also charged with the destruction of Birch 

 timber. 



Journ. fi.H.S. xxix. 1905, p. 754. 



OAK POLYPOBE. 



Polyporus dryadeus (Fries). 



This large polypore is said to attack the Oak, but too rarely to be of 

 much interest. It is expanded from the trunk in a semicircular manner, 

 is thick, and attached by a broad base, measuring up to ten inches across, 

 brown, rugged, with a paler margin which exudes drops of water. The 

 flesh is rusty and fibrous, somewhat zoned. Under surface porous ; spores 

 elliptical, colourless (5 x3 p). 



Hart. & Som. Dis. Trees, p. 201 ; Sacc. Syll. vi. 5196 ; Mass. PL 

 Dis. pp. 197, 391 ; Cooke, Hdbk. No. 771 ; Mass. Fun. Fl. p. 243. 



There are other species which have the same kind of reputation, but 

 not troublesome enough to be regarded as pests. 



STEREUM WOOD-ROT. 

 Stereum hirsutum (Fries), PI. XX. fig. 19. 



This is one of the most common of saprophytes on dead branches, 

 trunks, and stumps of all kinds ; but it has also the reputation of being a 

 destructive wound parasite. It is a tough leathery fungus, of a shell 

 shape, attached by the edge to the bark, spreading at right angles, with 

 the upper surface coarsely velvety, dingy-yellow, marked with zones, and 

 the margin often crisped and wavy. The under surface, which bears the 

 spores, is ochraceous -yellow. Mostly these pilei grow one above another 

 in an imbricated manner. The mycelium is perennial, and having once 

 obtained admission continues to spread, until all the living tissue is 

 destroyed. Spores globose, p diam. 



When found growing on living trees, it should be cut away, and the 

 wound washed with paraffin and afterwards painted with tar. 



Mass. PI. Dis. p. 175 ; Cooke, Hdbk. No. 911 ; Ward, Trans. Boy. 

 Soc. clxxxix. p. 123, pi. 17-21 (1898) ; Mass. Fun. Fl. i. p. 131 ; Hart. 

 <& Som. Dis. Trees, p. 205. 



PARTRIDGE WOOD. 

 Stereum frustulosum (Fries), PI. XX. fig. 20. 



This is another saprophyte which sometimes becomes parasitic, and 

 attacks various forest trees. It differs from the above in being closely 

 attached to the bark, with no portion free, the whole substance forming a 



