226 FUNGOID PESTS OF CULTIVATED PLANTS. 



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. 



Common in Europe, North America, and Cuba, and is known also as 

 Trametes radiciperda. 



Sacc. Syll. vi. 5487 ; Mass. PL Dis. p. 183, fig. 41 ; Cooke, Hdbk. 

 No. 788; Hart. & Som. Dis. Trees, p. 187, figs. 119, 120; Marshall 

 Ward, Timbers &c. p. 142, figs, ll, 12. 



DOUGLAS FIE BLIGHT. 

 Botrytis Douglassii (Tub.). 



Seedlings and young trees of the Douglas Fir and Welling tonia are 

 liable to have their leading shoots destroyed by this mould, which makes 

 its appearance as a brownish-grey mould on the branches, which soon 

 curve and die. The threads are brownish, either solitary or in tufts, 

 branched towards the summit, with the branchlets dilated, and toothed 

 or spinulose at the tips. Conidia grouped in heads, oval, colourless, 

 9 x6/i. Minute sclerotia are formed on the dead branches. 



With rather more zeal 'than judgment, Mr. Massee has called this 

 species Sclerotinia Douglassii, although he does not know that a Peziza 

 cup or sclerotinia has ever been produced, only that it might have been. 

 He seems to have forgotten that biology is a science of facts, and not of 

 dreams, and that we have no right to assume a fact until it can be 

 proved. Moreover, we have every reason to believe that this is no other 

 than Botrytis cinerea. 



Known also in Holland and Germany, 



Spraying with Bordeaux mixture at an early stage would destroy the 

 conidia and check the disease. When badly infected the plants should be 

 burnt at once. 



Sacc. Syll. x. 536; Mass. PL Dis. p. 160; Hart. & Som. Dis. Trees, 

 p. 180, fig. 71. 



Botrytis cinerea attacks seedlings of Conifers in Germany. It is 

 possible that the above may be the same species with another name. 



Journ. E.H.S. xxix. 1905, p. 775. 



Hypoderma nervisequum (DC.) 



is a common disease on the leaves of the Silver Fir in the Erzgebirge. 

 The leaves become yellowish-brown on the under side ; the midrib bears 

 a black longitudinal ridge. 



Hart. & Som. Dis. Trees, p. 108, figs. 52, 53 ; Sacc. Syll. ii. 5787. 



