Rhododendron. 163 



esses of development from the native forms to those 

 which we now so highly prize. Among the original 

 species which have been brought into reputation, but three 

 of the most prominent need be named. 



R. arboreum is the largest known species, and is some- 

 times called the tree rhododendron in allusion to its size 

 and form. It is a native of the Himalayan Mountains, 

 where it reaches the height of from twenty-five to thirty- 

 five feet, and sometimes, according to Nicholson, acquires 

 a circumference of 1 50 feet. The flowers are described as 

 white, rose, and blood color, disposed in dense heads and 

 very beautiful. The foliage is equally bold and showy, 

 "the leaves being large, coriaceous, lanceolate, acute, cor- 

 date at base, or attenuated into a thick petiole, of a beau- 

 tiful green above, below impressed with netted veins, 

 glabrous, silvery, or ferruginous-pubescent." Attention is 

 called to this species though it is known to be too tender 

 for out-of-door planting in this climate, except perhaps, in 

 our Southern States, and even then it is not recommended 

 for ordinary cultivation. 



Another of the foreign species is R. ponticum, which 

 also proves one of the most desirable members of the 

 family, and which, though hardier than the arboretnn, is yet 

 too tender for our use. It is a smaller plant, growing 

 six to ten feet, with good foliage and exquisitely beautiful 

 flowers. This is a native of Asia Minor, and while hardy 

 throughout most of continental Europe, it proves a prac- 

 tical failure in American cultivation, at least as far north 

 as New York. Though doing fairly well in England, the 

 extremes of heat and cold, and more especially of drought 



