AGARIl DS. 159 



' h'esin-.ulnt.' In the upper parts of the stem, where tin- cambium 

 and cortex are still sound, the turpentine also tl"\s- laterally, 

 liy means of the ducts of tin- medullary rays, from the injured canal- 

 towards the cambium and cortex. In the latter tin- accumulation 

 induees the fiirniatiou of large resin-bli-ter-. When, during tin- 

 summer, the cambium is forming a new riim, the plethora of 

 resin has the effect of cau-in- the production of numerou- re-in- 

 canal-. which are usually larue and abnormally constructed, and 

 these impart to the wood-rini; formed during thr year of -ick- 

 ness a very striking and characteristic appearance. 



'The mycelium gradually sjtreads from the cells of the 

 medullary ray- and from the resin-ducts into the va.-cidar 

 elements of the wood, where it produces a form of decay which 

 may lie termed a variety of white-rot. Ihirini: the pro-iv-- .,f 

 the decnmposition from the surface of the stem inward- a certain 

 -ta-e is reached, which is highly favourable to the development 

 of the mycelium. While previously it was -imply tiliform and 

 furnished with numerous lateral hyphae, it now develops lar^e 

 liladilei-like swellings, and at the same time the hyphae chai 

 into a kind of lar-e-meshed paivnchyma, which, like the i\l 

 in the vesscds of many dicotyledonous trees, comph-tely till- up 

 the lumina of the tracheides. On account of the mycelium 

 assuming a In-own colour when in this condition, it make- the 

 portion of diseased wood which it infests appear, to the naked 

 eye. like a Mack line. A.8 this kind of mycelium soon dies 

 oil' and is di--olved. liein- replaced liy a delicate filamentous 

 mycelium, it seldom happens that the /one which it occupies 

 ieds the breadth of three to four trachcid-. The wall- of 

 the elements nf the wood afterward- display a cellulose 

 reaction, ami -pe.-dily di--ol\e from the lumen oiu\\ard-. 



"On account of the trees drying up, after the rhi/.omorph- 

 have -pread from the point of infection on the root- into the 

 -tem, and a-ain from the -tem into the hitheilo -oiind root-. 

 decomposition of the stem usually ceases before the mycelium 

 has advanced from the alburnum into the duramen. It i- only 

 in ihe -tool ami roots that decay rapidly spreads t hiou-houl 



tile Whole of the \\ood." 



Method- foi exterminating tliis para-iteaie unkuo\\n. liexmid 

 removal of di-ea-e.l plant- ami collectimi of -porophm It 



\\oiild certainh' be advi-abh- not to jilant youn^ cointer- on 



