24 PRESENT-DAY GARDENING 
clarense, raised at Highclere in 1826, where R, arhoreum, 
which had been introduced from India six years earlier, 
was crossed with R. catawhiense. Although the last named 
had been crossed with the common R, ponticum, the Indian 
blood was needed to give variety of colour and those other 
qualities which characterise their hybrid descendants. 
Among the earliest breeders of Rhododendrons was 
Dean Herbert. In his classical treatise on Crosses and 
Hybrid Intermixtures among PlantSy written nearly a cen- 
tury ago, he pointed out that Rhododendrons offered a rich 
field to the hybridisers. He believed that all the species 
would intermix, and had even tried to cross R, indicum with 
other species, but found it refused to blend with any but its 
own immediate kindred, which is the experience of breeders 
to-day. The Dean crossed the Pontic Azalea with Rhodo- 
dendron, and the American Azaleas with R. arhoreum. He 
noted that the hybrids from R. arhoreum were impatient of 
wet ; also that they never bore fertile seeds. He also raised 
crosses between the Pontic and American Azaleas, between 
R. sinense and R. calendulaceum (thus anticipating the suc- 
cesses of Messrs. Cuthbert and Koster), between R. ponticum 
and R. catawhiense an amazingly florid hybrid between 
R. maximum and R. arhoreum (surely a good cross, but 
not now known to be in existence), between R. caucasicum 
and R. arhoreum^ and others. He recognised the import- 
ance of breeding for a later flowering habit and urged 
the use of R. maximum, which flowers in midsummer, to 
counteract the bad influence in this respect of R. arhoreum. 
Breeders to-day might make more use of the North 
American R. maximum. It grows on the Appalachian 
mountains up to an elevation of 3000 feet, often forming 
thickets hundreds of acres in extent, and is a bushy tree up 
