Variation
Betula platyphylla var. rockii
This tree grows to 15 m (45ft) tall with a whitish-coffee coloured smooth trunk with upright branches that are pendant towards the end forming a narrow domed habit.  It has diamond shaped, glossy dark green toothed leaves and is suitable for parks and large gardens.

Cultivar 
'Whitespire'
This upright tree has a trunk with very white bark and spreading branches, otherwise similar to the species.