294 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 
Finally, with regard to this aspect of the subject, the fact that 
the disease occurs in seedlings and cuttings growing on their own 
roots, and ungrafted, disposes once for all of the prejudice, which could 
not be entertained by "any experienced grower, that in grafting is 
to be found the cause of the disease. 
Now, as to the real cause of the disease, as I claimed in my previous 
lecture, it is undoubtedly due to a micro-organism. 
The parasite causes light-brown spots to form on the leaves, which 
spread down the petiole to the shoot, giving the foliage a sickly appear- 
ance. It also attacks the shoots when they have been injured or cut, 
causing gradual clogging and destruction of the cells, and extends 
downwards, until it arrives at the lateral shoot or shoots, causing them 
to succumb suddenly. 
The parasite apparently increases more rapidly with heat, thus 
accounting for the plants mostly dying back during the hot summer 
months, when they are in full growth, and sometimes in flower. 
Figure 60 clearly demonstrates the course of the disease. You 
see last year's growth, which has been broken off, or cut. The fungus 
entered the shoot at this wound, causing the cells gradually to decay, 
until it arrived at a node, when two shoots suddenly withered and 
died. The lower shoot, you will see, is quite healthy and growing, 
and there are plump, healthy buds shooting out from the main 
stem lower down. The roots are also perfectly healthy. 
This illustration also proves the correctness of the advice I gave 
in my previous lecture as to planting, when I recommended Clematis 
being put in a sufficient depth to allow the top of the union with the 
stock, being about 2 inches below the surface of the ground, in order 
to encourage the plant to form secondary roots, and to throw up 
strong shoots from below the surface. 
In this illustration you will again perceive that last season's shoot 
has been broken off a few inches above the level of the ground, a young 
shoot being sent up from the remaining eye. The parasite entered 
the old shoot at the wound, forced its way down the stem, encircling 
the node of the young shoot, causing it to succumb, the strong shoot 
on the left, coming from the main stem, being quite healthy. 
In the case of a plant which had been raised from a cutting, 
one eye at the top started into growth. The spores of the parasite 
attacked the leaves in the early stages and spread down the petiole 
to the shoot, arriving at the node at the top of the cutting, killing 
both the main stem and lateral shoot, whilst the other bud at the 
top of the cutting endeavoured to push into growth, though its life 
could be of but short duration.* 
The seedling figured (fig. 61) is three years old, and has grown 
well until this summer, when the parasite attacked it at the injury 
some three feet up the stem, killing all the branches above, whilst 
the lower portion of the main stem is still alive. 
Since stating my conclusion that the disease is due to a micro- 
* The lecturer showed an example bearing out his statement. 
