VEGETABLE MORPHOLOGY. 
415 
of very great size. Such may be frequently seen on aged beech and 
elm trees, and which, when cut up for use, are highly prized by 
cabinet-makers for cutting into veneers. 
Vegetable membrane is sometimes curiously distorted by insects. 
Ihe mossy tufts on the sweetbrier and dog-rose; the various sorts of 
galls seen on the buds, leaves, and petioles of oak-trees, showing the 
most elegant subdivision, and regular expansion of the cuticle, and 
transformation of the various members; are all the works of insects, 
and are similar to the tubercles, called ‘ f fingers and toes,” on the 
stems and tubers of the genus Brassica . Other insects, as the Eriosma, 
corrode and blister the bark, causing unnatural prominences and 
enlargements, every way unlike the natural expansion of the parts. 
Whether we examine the regular forms and beauty of the oak-galls, or 
the irregular moss-like tufts on the brier, we cannot but be surprised 
at the versatile nature of vegetable membrane, that can be turned into 
forms so decidedly different from any other part of those plants, and 
by an obstruction so minute as the egg of a very small fly, deposited in 
one of the sap-vessels of the bud or leaf: and, if a result so remarkable 
be caused by the interposition of so small an agent, how much more 
must the manipulations of the cultivator affect the ordinary evolutions 
of plants, and cause them to fly from their normal habits? 
It is observable that such departures from the normal or natural 
form (as a shoot growing through a terminal dower or fruit), only occur 
among the highly-pampered varieties of flowers or fruit, such incidents 
being rarely met with among plants in a state of nature. Hence it has 
been long considered by old gardeners, as well as the older botanists, 
that such phenomena and irregularities were solely attributable to high 
cultivation, causing derangement in the structural habit in consequence 
of the various expedients of culture to which they were subjected. 
These variations in the growth of domesticated plants are very 
similar to what takes place among domesticated animals. For proof, 
we have only to consider what diversity of size, and shape, and colour 
obtain among our herds and flocks, in our stables, kennels, and poultry- 
yards ; all which variety is evidently the result of domestication. 
From these instances of metamorphosis, to which both animals and 
vegetables are subject, under the expedients of culture or attack of 
insects, we may reasonably conclude that the membranes of the latter, 
and the constitutional structure of the former, are both susceptible of 
derangement, in so far as their external integuments or members are 
liable to foreign or artificial influences. 
But the metamorphosis of plants is explained and accounted for in a 
very different manner by several of our first-rate modern botanists; they 
