. Contributions from the Botanical Laboratory and the Morris Arboretum of the University of Pennsylvania, vol. 14. Botany; Botany. 46 Phytopathology [Vol. 28 'â °"'pTyToSh'^2st8l!Sr"7935.'''""' ^^'^^^'"'^ '" " gall-forming Periaern^iurn. 7. Klebahn, H. Peridermium pini CWilld ^ K^^^h i,t,^ o«,-« -^vu ^ 1929. i"'Perments repeating pine rusts. 19: 327-342 ,'⢠^'""^'uficl'^- ptIoTX ^:"^J^ ''^Zr''"' """'""^'^ '^ Pâ¢^'-«» of the â 7''Gtââ¢"na"âftor"lt7'" "â ' ^&qu
. Contributions from the Botanical Laboratory and the Morris Arboretum of the University of Pennsylvania, vol. 14. Botany; Botany. 46 Phytopathology [Vol. 28 'â °"'pTyToSh'^2st8l!Sr"7935.'''""' ^^'^^^'"'^ '" " gall-forming Periaern^iurn. 7. Klebahn, H. Peridermium pini CWilld ^ K^^^h i,t,^ o«,-« -^vu ^ 1929. i"'Perments repeating pine rusts. 19: 327-342 ,'⢠^'""^'uficl'^- ptIoTX ^:"^J^ ''^Zr''"' """'""^'^ '^ Pâ¢^'-«» of the â 7''Gtââ¢"na"âftor"lt7'" "â ' ^"'^ ^-'-» gymnosperms. ... 374 pp. 11. Sâ¢.,_A^ Note^, ââ j,â ,â,iââ^ â, ^^â.^^^^,.^^ ^^^_^ ^ ^_^^^ ^^^^ ^^^ 12. WEia, X ^ Observations on the pathology of the .jack pine. U. S. Dcpt. Agr. Bull "â l°"Aioo%1ttTe "'-' '" *'''' N-"'-t"n United States. Science â '""^e^be'ddin^g"." i%ti':tf,rr^oUs,'xr'''' ^""^«-- ^^ p-am⢠> 4 ⢠?^ V « :: - ⢠k. PLATE I 1. Transverse section of a normal twig of P. sylvcstris as it appears in early June. Note especially the thickness of the walls of epidermal and subepidermal cells at a, the base of the needle fascicle supplied by the bundle trace at b as contrasted with the thinner walls elsewhere as at c. 2-3. Transverse sections showing unresisted invasions. 2. shows a very limited necrosis at point of penetration (A), scarcity of hyphae in the outer cortical region as compared with the inner, especially in the vicinity of the resin canal and the closing of the canal by the hypertrophy of the epithelial cells. The mycelium is shown entering the stelar tissues through a bundle trace at b. 3 shows a resin canal still open in spite of the abundance of hyphae near-by. The mycelium enters the phloem of the main stele at a. 4. Early stage in the formation of the "collar". Necrosis has spread from near the center of infection
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Keywords: ., bookcentury1900, bookpublisherphiladelphiasn, booksubjectbotany
