a 
260 BORTHWICK—A NEW DISEASE OF PICEA. 
higher up, although no part of the tree was entirely free from 
infection. The fungus attacks the buds, and in some cases 
prevents their further growth. If, however, the bud is only 
affected on one side a slight amount of elongation may take 
place, but in every case the result is a twisted shoot. 
An external examination shews that the buds have become 
encased in a dense black sheath, the surface of which is thickly 
dotted with spherical papilla each with a small opening at the 
top (Fig. 4). The general appearance of the disease is shewn in 
Fig. 2, while the lower left-hand bud of this twig is given more 
highly magnified in Fig. 3. 
Microscopical examination shews that these papille are the 
fructifications of a pyrenocarpous ascomycete. The mycelium is 
intercellular, and penetrates the cortex in all directions. At 
first, apparently, the threads are single, but finally dense wefts 
and strands of tough pseudo-parenchymatous tissues are formed 
which divide the cortex into conspicuous quadrangular areas 
consisting of brown collapsed cells (see Fig. 4). The hollow 
space in the centre of these quadrangular areas was previously 
filled with a mycelial pseudo-parenchyma, but this easily drops 
out in mounting the section, leaving a hollow circular cavity 
behind. To the exterior the mycelium forms a dense black 
stroma, the surface of which is thickly dotted with the pear- 
shaped fructifications of the fungus. 
The pear-shaped fruit bodies (pyrenocarps) have walls con 
sisting of small-celled dark brown pseudo-parenchymatous tissue, 
very dense at the outside but becoming less compact inwards. 
The base of the pear-shaped cavity of the pyrenocarp is occupied 
by a distinct hymenium of paraphyses and asci. The develop- 
ment of the asci seems to be successive, at least they were found 
in various stages of maturity in each fructification. As they 
ome ripe they push up towards the apical pore, hence the 
spores appear to be liberated gradually. The number of spores in 
each ascus varies from 4 to 6, arranged in a uniseriate manner, 
and they are of a dark brown colour, and measure 20 by 6 p. 
They become multi-cellular by the formation of transverse and 
and longitudinal septa. In outline they are torpedo-shaped with 
fairly sharply-pointed ends (see Fig. 5). 
{n material taken from the tree in the months of May and 
