HEART-ROT CAUSED BY OTHER FUNGI 141 
tion in this country. Rostrup (1902) does not include it 
among Danish fungal diseases. In India it occurs on Pinus 
excelsa (Mayes, 1905). 
The fructification of the fungus is of Polyporus form, and 
may be composed of either a single large bracket (up to 
9 in. wide), numerous imbricated small brackets, or ‘ re- 
supinate’ incrustations which may spread for 10 ft. or 
more on the under-side of branches or fallen trunks. It is 
hard, woody, and perennial, and is most easily distinguished 
by the light red-brown colour of the lower surface, which 
is pierced by small pores. The pores are round, but appear 
elongated where the surface is not horizontal, a feature, 
however, which the fungus has in common with many 
allied species. Brackets are produced freely on dead trees, 
and the spread of the fungus is chiefly secured by these 
post-mortem growths. The hymenial surface which lines 
the pores bears basidiospores which are 5—6 X 3-4 yp, and 
is characterized by elongated, brown, pointed, thick-walled, 
spine-like paraphyses or ‘cystidia’ not unlike those figured 
in Polyporus Schweinitzii. They persist in the pores for 
a long time after the region bearing them has ceased to 
produce spores. 
The process of decomposition induced in the wood by 
the fungus has been described by Hartig (1878) and Schrenk 
(1900). From the infected branch narrow red-brown streaks 
spread both upwards and downwards in the trunk. Though 
these streaks scarcely spread at all in a radial direction, 
they may become tangentially extended in the annual ring 
or rings in which they were initiated, and in this way 
produce a kind of ring-shake in the tree. Several partial 
rings of this nature may arise before the centre of the tree 
is appreciably affected. The wood outside the red-brown 
area becomes suffused with turpentine and resin, which to 
a considerable extent limit the spread of the mycelium. 
White flecks then appear in the red rot portions, which are 
occasionally, but by no means always, preceded by black 
spots similar to those caused by Fomes annosus. ‘These 
flecks are much larger than those produced by F. annosus, 
