270 ARISTOCRATS OF THE GARDEN 



Of the introduced species of Rhododendron with 

 large evergreen leaves five only are hardy in the 

 Arnold Arboretum. These are the native R. maxi- 

 mum and R. catawbiense, R. Smirnowii and R. cau- 

 casicum from the Caucasus, and R. brachycarpum from 

 northern Japan and northern Korea. One other 

 species (R. chrysanthum) with pale yellow flowers 

 ought to be hardy here for it grows in the cold regions 

 of northeastern Asia and on the tops of high moun- 

 tains in Hokkaido, Japan, where I have gathered 

 it in flower on the last days of July with unmelted 

 snow in patches lying around. It is, however, an 

 alpine plant and though introduced to cultivation 

 about 1800, and again about 1850, has never been a 

 successful garden plant. This being the case it is 

 on the above-named five species that all our hopes 

 are centred and it is in the commingling of their 

 blood that we must look for the foundations of a 

 race of large-leaved evergreen Rhododendrons capa- 

 ble of withstanding the rigors and vagaries of this 

 climate. And we are really fortunate to possess 

 five species which, as we have seen, is more than was 

 known when the work began in England. 



Theoretically, if the parents are hardy the off- 

 spring will be equally so, but in plant-breeding this 

 does not always work out in practice. For example, 



