PANUS STYPTICUS 359 



an astringeot action on the palate and throat. They often contain 

 a certain amount of tannin, as may be proved by the blue reaction 

 given with certain iron salts ; but this tannin, here as in other 

 lignicolous agarics, appears not to be manufactured by the fungus 

 durijig its metabolic activity but merely to be absorbed from the 

 substratum upon which the fungus grows.^ Bourquelot found that 

 some fruit-bodies which he analysed contained 1 • 6 per cent, tre- 

 halose and traces of mannite and grape-sugar.^ Rosoll extracted 

 from the fruit-bodies a brown pigment which is soluble in alcohol 

 and ether and turns a dirty red with sulphuric acid. The alcoholic 

 solution has a green fluorescence.^ 



The Length of Spores of English and North American Origin. 

 — Fruit-bodies of Panus stypticus were collected at : (1) Great 

 Missenden, England ; (2) West Malvern, England ; (3) Ann 

 Arbor, Michigan, U.S.A. ; (4) Saint Paul, Minnesota, U.S.A. ; and 

 (5) Ottawa, Ontario, Canada. After revival in the laboratory, they 

 all gave rise to copious spore-deposits. At my request, Mr. W. F. 

 Hanna, using the very accurate plate-micrometer method already 

 described in Volume I, measured the lengths of the spores in all 

 the five spore-deposits. As a result of measuring 100 spores in 

 each deposit, he found that the average length of the spores was : 

 for (1) a Great Missenden fruit-body, 5-3 /x ; for (2) a West Malvern 

 fruit-body, 5-3 /i; for (3) an Ann Arbor fruit-body, 5-0 /la; for 

 (4) a Saint Paul fruit-body, 5-2 /x; and for (5) an Ottawa fruit-body, 

 5-1 /x. Thus the variation in the average length of the spores for 

 all these five fruit-bodies taken together was only 5 -0-5 -3 yu.. It 

 is clear, therefore, that no varietal distinction between the English 

 and North American fruit-bodies could be made on the basis of 

 spore size. 



The Divergence of Imbricating Fruit-bodies.— It not infre- 

 quently happens that the fruit-bodies of Panus stypticus are 

 caespitose, and then the individual fruit-bodies of a single cluster 

 diverge from one another. This is well shown in the vertical section 

 represented in Figure 161. Here, from above downwards, the first 

 stipe ascends at an angle of about 65°, the second ascends at an 



^ Vide Julius Zellner, Chemie der Hoheren Pilze, Leipzig, 1907, p. 134. 

 2 Ibid., p. 103. 3 ji^id^^ p^ 169. 



