BOTANICAL SOCIETY OF CANADA. 
47 
A few particulars respecting the plaut on which the new silk-worm feeds may 
not be unacceptable. The genus ailanthus consists of large trees, whose timber is 
used for various purposes in the countries in which they grow, Ailanthus glandu- 
losa is a native of China and Japan. The French name is Ailante. In Hortus Kew- 
wensis we see that it was introduced into England by Father D'Incarville in the 
year 1751. It grows well in England, as well as in the United States, and is 
regarded as a valuable tree, as it is a quick grower and thrives on a poor soil. It 
has been recommended as a shade tree to be planted in the streets, or where shade 
is required. Trees of this and of the Mulberry planted in rows along the sidewalks 
in cities would answer three purposes — shade, food for silk-worms, and ornament. 
Groves and carriage drives so decorated would be pleasant and handsome-looking. 
Judging from the complaints of some horticultaral writers as to its troublesome 
character, the Ailanthus would seem to grow too freely in the United States. See 
Horticulturist, N. Y., 2 ser., vol. v., page 379. In Gray's Manual it is described as hav- 
ing flowers, especially the staminate ones, which are redolent of anything but " airs of 
heaven." The bad odor, he observes, offers a serious objection to the planting of 
this ornamental tree near dwellings ; but for the production of silk the trees are 
pollarded, or cut to stumps, and will not therefore produce flowers freely. When 
allowed to grow freely the Ailanthus attains a height of sixty feet. The bark, when 
wounded gives out a resinous juice, which hardens in a few days. The wood is hard 
and heavy, and is susceptible of a very fine polish. The late Dr. Neill of Edinburgh, 
in the account of his visit to Paris in 1817, says : In the Jardine de Plantes, next to 
the Seine gate, the cross-walk is shaded by rows of the Ailanthus glandulosa, here 
forming trees of considerable size. The Ailanthus, he remarked, seemed to have 
become a common ornamental tree at Paris. Again, the same writer observes that 
" at the back part of the garden there was a wall lined with the Ailanthus glandu- 
losa, a Japan tree, which was growing vigorously, and remained quite green though 
standing in the hard gravel walks ; while the Lime trees had been burnt up or 
nearly deprived of their foliage by heat or drought. It will grow in the coarsest 
and poorest soil, and sends its spreading roots abroad in search of moisture and 
nourishment. It is chiefly propagated by means oi chips or cuttings of the roots, 
which are placed in shallow trenches, and grow readily," From these remarks we 
see that the tree has long been appreciated in France as an ornamental object, and 
now a rich harvest of silk will be reaped from it. 
The importance of silk to our civilized world, not only in the present day, but 
in all ages, and the constant demand, still on the increase, have led naturalists to 
look out for insects that produce silk cocoons; and the last new discovery in France 
is that of the Ailante. We have thus at least three insects that could be reared iu 
Canada for silk: — 1. The Cecropia, a native of North America, and the food of 
which is already established, as it feeds upon the wild plum, the apple, and cherry 
