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Scientific Memoirs by

In many instances the prominences which they form are half as thick as the
stem or bough from which they originate. Ultimately, processes of destructive
disintegration set in in the mass, and now the mycelium no longer confines itself
to vegetative growth, but gives origin to fructification in the form of crops of
deep rusty-brown pilei (Plate VI, Fig. II) of woody texture and presenting the
structural features characteristic of those of the genus Trameter. As the decay
of the host-tissues advances, masses of the tumour fall away carrying the earlier
crops of pilei with them, and leaving raw surfaces exposed, from which fresh
crops originate. In consequence of frequent repetitions of these processes, the
bulk of the morbid tissue becomes greatly reduced, but, as the invasion of
healthy areas continues simultaneously to progress, any spontaneous cure of the
disease does not tend to occur. On the contrary, the general nutrition of the
host ultimately comes to be seriously interfered with by the spread of the
parasite, and, at the same time, so much. weakening is induced by the steady
disintegrative loss of tissue, that fractures are readily induced under the
influence of any sudden strain such as that caused by gusts of wind.

   The appearances presented by the morbid tissues in the earlier stages of
the disease, ere disintegrative changes have begun to occur, are illustrated in
Fig. 8 of Plate V, which represents a portion of a section through the substance
of one of the localised tumours which originate where the original site of inva-
sion is in an embryonic shoot. The particular growth from which the section
was obtained was still of small size and its outer surface was quite intact and
covered with seemingly normal bark. It will be seen from the figure that the
substance of the wood is everywhere permeated by large filaments of a deep-
brown, branching, septate mycelium which occur in especial abundance in the
large pitted vessels and the tissues of the medullary rays, whilst the wood-cells
remain practically exempt. The details of the structure of the mycelium are
further illustrated in Fig. 9, which represents portions of individual filaments
from various parts of the same section.

   This blight is exceedingly common among, and eventually destructive to,
trees of Terminalia Catappa in the neighbourhood of Calcutta, but there is
little doubt that it might be practically abolished were a little attention bestowed
on detecting and treating it at an early stage of its development. It so early
shows conspicuous indications of its presence, that its invasion can hardly escape
notice at a stage long before the parasite has begun to fructify, and when the
diseased tissues might readily be completely removed by means of free excision.
Such treatment would effectually prevent its further local extension, and also the
development of the reproductive elements securing its infective invasion of other
hosts, and, considering the ornamental and economic properties of the tree, it is
certainly a pity that it should be allowed to suffer as it does.