TREES IN TOWNS 49 
the specimens which I have seen appear to have come from 
Van Houtte’s nursery in Belgium, where they were grown 
under the name Platanus orientalis, var. californica, 
Birch is a most useful tree in towns, and the silver birch 
(Betula verrucosa), which resists drought much better than 
the common species (Betula pubescens), should always be 
chosen. It also succeeds well where there is much lime in 
the soil and is very beautiful both in summer and winter, 
with its pendulous branches and very white bark. 
Poplars thrive in towns and succeed in heavy clay soils 
where other trees fail. The European black poplar, Populus 
nigra, may be tried in streets, but its foliage and form are 
unattractive, and its trunk develops ugly burrs when old. 
The Lombardy poplar, a male tree always propagated by cut- 
tings, which originated as a sport in Northern Italy about 
200 years ago, has been styled the ‘ Exclamation Point’ in 
landscape architecture, and it can often be used effectually 
in towns. The hybrid black poplars, which have been pro- 
duced accidentally by the crossing of the European and 
American species, include several kinds, of which the black 
Italian poplar (Populus serotina), a male tree, and the 
Eucalyptus poplar (Populus regenerata), a female tree, are 
the commonest in cultivation in England. They grow 
speedily to an immense size, and on that account are un- 
suitable for ordinary street planting. In town parks they 
should be avoided, as they do not harmonise with other 
trees, which they speedily overtop; while in windswept 
districts they are likely to be smashed by gales. If, how- 
ever, a quick effect is desired, the best of these hybrids is 
Populus robusta, a narrow tree with branches ascending at 
an angle and not directed vertically upwards as in the 
Lombardy poplar. This is well suited for making an avenue 
or line of trees in a park, that would attain a great height 
in a few years, its average rate of growth being about three 
feet annually. The white poplar (Populus alba) and the 
grey poplar (Populus canescens) have beautiful foliage, and 
are much more desirable for street planting than the black 
poplar. Bolle’s poplar (Populus alba, var. Bolleana), the 
E 
