TEEES 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 

 {Bctula verrucosa), which resists drought much better than 

 the common species {Betula puhcscens), 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 Lorabardy 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 {Popidus serotina), a male tree, and the 

 Eucalyptus poplar {Popnhis 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 rohusta, 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 



