132 TRANSACTIONS OF ROYAL SCOTTISH ARBORICULTURAL SOCIETY. 
Warrington, where the noxious emanations from alkali and other 
chemical works are most disastrous in their effect on trees and 
shrubs, the sycamore is one of the few that grow satisfactorily. 
Being a rapid and strong grower, it is thus seen to be, for a certain 
time at least, unaffected by its inimical surroundings. The 
variegated variety would seem from recent experiments to be 
preferable and better adapted for smoky localities than the normal 
form. 
The Weeping Ash (fraxinus eacelsior pendula) would seem to 
be superior to the common ash for planting in towns. It thrives 
satisfactorily in many of our largest centres of industry—to wit, 
London, Liverpool, Glasgow, and Manchester. Being of slow 
growth and dwarf in size, it is well suited for planting where space 
is confined. It is of the easiest culture. 
The Horse Chestnut (@sculus Hippocastanum) and the English 
Elm (Ulmus campestre) may be seen in a fairly satisfactory way in 
many town parks, but only where they are not exposed to smoke 
and soot to any great extent. In confined spaces both these trees 
soon show signs of distress, the points of the branches gradually 
becoming unhealthy, and the trees ultimately dying off prema- 
turely. Taking everything into consideration, neither of these trees 
can be recommended for planting in smoky districts. 
The Birch, Walnut, Hornbeam, and one or two kinds of Willow 
will succeed in the less smoky parts of a town; but they are not to 
be recommended for planting where the air is constantly impreg- 
nated with soot and dust. 
The Mountain Ash, or Rowan Tree (Pyrus aucuparia), has proved 
itself to be a valuable small-growing tree for planting in urban 
districts. It is also a tree of great beauty, whether in flower or 
fruit, one that grows almost anywhere, and with a minimum of 
attention. In many town streets where the air is vitiated with 
fumes, the mountain ash grows with great freedom. 
The Alder (Alnus cordifolia).—In this we have a good addition 
to the few trees that are really suitable for town planting, for it 
grows with great vigour, and retains much of its fresh, spring-tide 
greenness in very smoky and impure localities. Of hardy con- 
stitution, and unusually strong growth, it seems to defy the sooty 
emanations from hundreds of chimneys in two at least of our largest 
centres of industry. 
The Bird Cherry (Cerasus Padus) may be classed among the | 
most valuable of our town trees. It is a robust-growing and bright- 
