FUNGOID PESTS OF FOE EST TREES. 



387 



Pustules linear (up to 2 cm. long), either solitary or crowded, orange- 

 yellow. Uredospores rounded or ovoid, angular by compression, warted 

 (15-20 n diam.), pale reddish-yellow. 



Sacc. Syll. vii. 3141; Mass, Dis. PL 236, fig. 60; Hart. 6 Som. 

 Dis. Trees, p. 166, figs. 97, 98, 99. 



Spruce Nectria. 

 Nectria cucurbitula (Fries), PI. XXI. fig. 51. 



This common Nectria occurs usually as a saprophyte, but it also 

 becomes a wound parasite, and attacks the Spruce, or less commonly the 

 Silver Fir. The red perithelia burst through the back, which is killed, and 

 ultimately the wood dries up and dies. The perithecia produce colourless 

 sporidia contained in asci (14-18 x 6-7 //), uniseptate and binucleate. 



Hart, d- Som. Dis. Trees, p. 89, figs. 37, 38 ; Mass. PI. Bis. p. 130 ; 

 Cooke, Hdhk. No. 2349 ; Sacc. Syll. ii. 4680. 



Spruce Woolly Sphjrria. 

 T richo splicer ia parasitica (Hart.). 



This parasite of the Spruce and Silver Fir appears on the young 

 branches, spreading to the under side of the leaves, and is well known in 

 parts of Europe. 



Hart. & Som. Dis. Trees, p. 72, fig. 18. 



Black Woolly Sph^ria. 



Herpotrichia nigra (Hart.). 



Is destructive to Spruce in the Bavarian forests.' 

 Hart. & Som. Dis. Trees, p. 76, figs. 24, 25. 



Conifer Root Rot. 

 Fomes annosus (Fr.). 



This has the reputation of being one of the most destructive fungi 

 which attack Conifers. Germinating spores gain an entrance into the 

 living tissue of the roots and form a thin white mycelium between the 

 bark and the wood. The cell contents change to a brown colour, and the 

 wood soon assumes a pale yellowish-brown colour, with scattered white 

 patches, each with a black spot in the centre. 



The complete fungus is variable in size and form, sometimes resembling 

 a thin white cake, with the porous surface uppermost, and one or two inches 

 in diameter. When perfect, the pileus is expanded, thin and overlapping one 

 above another, the upper surface brown, irregularly tuberculose and wrinkled, 

 sometimes concentrically zoned, silky at first but afterwards smooth. The 

 substance is white, hard, and woody ; the under surface white and porous. 

 Sometimes six inches across, and once we found a confluent mass upwards 

 of fourteen inches in diameter. 



Diseased trees should be removed, with all the roots and fragments of 

 diseased roots, and all examples of the polypore destroyed. 



