Miss Dale, Notes on Artificial Cultures of Xylaria. 101 
which have produced conidia ultimately shrink and become over- 
run by the flocculent parts of the mycelium. The sterile stromata 
are still growing. Free conidiophores were also produced in 
X. polymorpha, while in X. Hypoxylon conidia were developed on 
small tufts of hyphae united into coremium-like bodies. Up to 
the present, only the conidia from the free conidiophores of 
X. polymorpha have germinated 1 . They give rise to a thin 
mycelium which slowly spreads over the substratum and which is 
very unlike the dense flocculent masses so rapidly formed from 
ascospores, although the young mycelia as seen under the micro- 
scope are very similar In both cases. 
The structure of these conidiophores as seen in microtome 
sections is remarkably like that of certain Basidiomycetes. The 
centre of the organ consists of a dense mass of hyphae, somewhat 
interlacing but running approximately parallel to the long axis. 
Towards the periphery the tissue becomes looser and bends out- 
wards, forming parallel branches which stand close together like a 
hymenium. The branches are septate and each forms a single 
spore on a sterigma-like process which, after the abstriction of the 
spore, remains as a pointed prolongation of the spore-bearing 
branch. 
The action of the fungus in destroying the wood which forms 
its substratum shews some points of interest. Pieces of wood 
were hardened in Flemming’s solution, and transverse, radial, and 
tangential sections were cut. The hyphae had penetrated into all 
the tissues and could be seen running along the medullary rays 
and down the vessels, wood-fibres, and wood parenchyma. The 
hyphae varied considerably in thickness, the larger ones being 
chiefly in the wide vessels. In all cases the mycelium passed 
from cell to cell by means of the pits. One of the most striking 
points is the way in which the wood-fibres are affected. In radial 
sections some of the hyphae in the fibres are seen to run in a 
straight line, while others take a spiral course and are united to 
the straight hyphae by connecting branches. The explanation of 
this seems to be that the hyphae make their way first into the often 
narrow lumen of a fibre, and that from these hyphae there are 
formed branches which penetrate the pits and grow spirally round 
in the wall, decomposing it as they go, evidently by excreting 
some wood-destroying enzyme. Often two or three hyphae may 
be seen forming as many spirals round a fibre and lying in 
channels which they have made in the cell-wall. 
1 Since the above notes were written conidia from old conidiophores of Xylaria 
■polymorpha have germinated. 
