On the Occurrence of Cellulose in the Xylem 
of Woody Stems. 
BY 
M. C. POTTER, M.A., 
Professor of Botany in the University of Durham College of Science , Newcastle-upon-Tyne . 
With Plate VIII. 
T HE appearance of cellulose in the xylem of various trees when attacked 
by certain wood-destroying Fungi has been noted, and has been 
attributed to the action of a delignifying enzyme secreted by the Fungi. 
Hartig (78), in his classic work upon the destruction of the wood of 
Conifers and of the Oak by certain Fungi, has given an account of the 
appearance of cellulose in the wood when under the influence of such 
attack. In the Oak, he describes in detail the special action upon the wood 
of Telephora perdix, Polyporus ignarius, P. dryadeus, and Stereum hirsutum , 
and states in each case that in the process of decay the lignified walls 
become converted into cellulose, attributing this change to the delignifica- 
tion by the hyphae. In the wood of the Conifers the same appearance 
is noted and ascribed to the influence of Trametes and other Fungi. 
Mayr (’84) attributes the presence of cellulose in the stem of Betula 
to the action of the parasitic Fungi Polyporus betulinus and P. laevigatus. 
Marshall Ward (’97'), studying the action of Stereum hirsutum upon 
the wood of Aesculus, has demonstrated the presence of cellulose in the 
xylem when infected by a pure culture of this Fungus. The swollen inner 
layers of the cell-wall become delignified and consist entirely or almost 
entirely of cellulose, as shown by the differentiating colour-tests of chlor- 
zinc-iodine, and phloroglucin. The hyphae attack the walls of the 
tracheides and other wood-elements, and, he considers, gradually delignify 
them from the lumen outwards. Marshall Ward assumes the presence 
of an enzyme which effects the delignification, but ‘ did not succeed in 
extracting the enzyme from his cultures.’ 
Biffen (’01) has published some investigations upon the biology of 
Bulgaria polymorpha and the effects of its action on wood. Sections from 
a block of Oak thoroughly permeated by hyphae showed a swelling of the 
[Annals of Botany, Vol. XVIII. No. LXIX, January, 1904.] 
