. Fig. 13. Fig. 14. Fio. 13.—Tracheid of Pinus si/lvestris destroyed by Trametes pint. The primary cell-Wall is completely dissolved from below upwards to a, a ; 6, secondary and tertiary layers of the walls consisting in the under portion of cellulose only, in wliich granules of chalk are recoffnizable ; c, fungus-hyphae boring through the walls, leaving holes d and c. (After R. Hartig.) Fig. 14.—Tracheid of Pinus destroyed by Polyporui Schweiiiitzii. The cellulose has been extracted, and the wall consists only of wood-gum. The fissures are a result of drying-up, but they do not extend into t
. Fig. 13. Fig. 14. Fio. 13.—Tracheid of Pinus si/lvestris destroyed by Trametes pint. The primary cell-Wall is completely dissolved from below upwards to a, a ; 6, secondary and tertiary layers of the walls consisting in the under portion of cellulose only, in wliich granules of chalk are recoffnizable ; c, fungus-hyphae boring through the walls, leaving holes d and c. (After R. Hartig.) Fig. 14.—Tracheid of Pinus destroyed by Polyporui Schweiiiitzii. The cellulose has been extracted, and the wall consists only of wood-gum. The fissures are a result of drying-up, but they do not extend into the primary wall a, h. Crossing of the fissures takes place at the bordered pits c, and at the bore-holes d and e; /, simple fissures. (After R. Hartig.) kind, the primary wall, containing but little , is hardly affected, and the secondary membranes shrink together, so that numerous fissures are produced running in a spiral direction, corresponding with that of the stratification (Figs. 13 and 14.) The tertiary membrane varies in its nature ; it may consist of pure cellulose or be more or less lignified, or even cuticularized. In the wood-fibres of some plants {Cytisus, Hamulus,) this
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Keywords: ., bookcentury1800, bookdecade1890, bookpublisherl, booksubjectfungi
