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AMERICAN AZALEAS AND THEIR HYBRIDS. 
A Letter from Professor Charles S. Sargent. 
Dear Mr. Williams, 
Your letter of September 18th has remained too long unanswered, but I shall 
now try to answer some of the questions about the American Azaleas which are 
embodied in that letter. 
1. Descriptive characters. The best technical description of the well-known 
species is found in the new edition of Bailey’s Cyclopedia of American 
Horticulture. This description was prepared here at the Arboretum by 
Mr. Alfred Rehder from material in this collection. 
2. Habitat. Rhododendron viscosum, R. canadense and probably 
R. OBLONGiFOLiUM inhabit swamps. The other species so far as I know grow 
naturally in upland valleys, on mountain slopes or in open oak woods. None 
of the species are found growing in soil impregnated with lime. 
3. Date of introduction and discovery. The old species were no doubt 
cultivated in Europe long before they were cultivated in the United States, and 
the dates of their introduction into European gardens and discovery can be 
found in the records of European horticulture, as for example in Aiton’s Hortus 
Ke WEN sis. 
Rhododendron Vaseyi was discovered by George R. Vasey in 1878, near 
Webster, Jackson County, North Carolina, and was introduced into the Arnold 
Arboretum in 1880. I have no record that it was cultivated earlier. About 
that time we sent seeds to Anthony Waterer of the KnaphiU Nurseries. 
Rhododendron occidentale. According to the Botanical Magazine 
(t. 5005), this species was introduced into England before 1857. It was in the 
Arboretum in 1865, and it was about that time, or a little earlier, that I sent seeds 
to Anthony Waterer, who raised from these seeds the plants used by him in the 
production of his race of hybrids of this species. 
Azalea austrina. Small. This species was first raised in the Arboretum 
from seeds collected in November, 1913, for the Arboretum by T. G. Harbison. 
This is undoubtedly the date which must be taken as the introduction of this 
species into cultivation. Plants were sent to Kew in November, 1916. It may 
be described as a yellow-flowered Rhododendron nudiflorum. It is common 
in open oak woods in the vicinity of River Junction, at the head of the 
Appalachicola River, in Western Florida. It is an extremely beautiful plant. 
There is little hope that it will be hardy either here or in Great Britain. Plants 
have been sent to you this autumn. 
Azalea Candida, Small. (Bull. Torrey Bot. Club, XVIII., 361). The 
type locality for this species is in the neighbourhood of Valdosta, in Laundes 
County, Georgia, where it was first collected by Small, in June, 1895. Valdosta 
is in the extreme southern part of Georgia, and this distinct species will probably 
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