Additional Notes on the Azaleas and Rhododendrons of the Blue Ridge Mountains
Frederick P. Lee
In the January 1958 issue of American Rhododendron Society Bulletin Mr. David G. Leach, in his article entitled "A New Look at the Azaleas and Rhododendrons of the Blue Ridge Mountains," comments on the "gigantic melee of intermingling (azalea) species" he observed at stations in those mountains in June of 1957. He expresses wonder that these species and wild hybrids or intergrades "have been so inadequately studied by botanists" and seemingly "shunned" by them. After referring to species crossing "in the wilderness on a colossal scale," he adds "No real intimation of the magnitude and frequency of this occurrence has been published to the best of my knowledge." In consequence it may be helpful to point out the exhaustive studies of the living materials that have already been made and to bring such studies to the attention of members of the Society who, like Mr. Leach, may be unfamiliar with the work already done.
Collections of the red azalea of Black Mountain, Kentucky, and of the swarms on Gregory Bald and elsewhere were made more than twenty years ago by Dr. Wendell H. Camp, present head of the Department of Botany, University of Connecticut, who recognized the probable hybrid origin of many of these plants.
In her paper describing R. cumberlandense in 1941 Dr. E. Luey Braun of the University of Cincinnati noted the variable intermediacy of the flame azaleas of the Nantahala Region between R. calendulaceum and R. cumberlandense . Because of the "great range in time of bloom and in relative maturity of leaves at blossom time which is displayed by flame azaleas of the Southern Blue Ridge province (especially the Great Smokey Mountains) where there is a succession of bloom from May to July," Dr. Braun suggested that "perhaps all are hybrids."
Commencing in 1951 Dr. Henry T. Skinner, now director of the United States Arboretum, conducted field investigations of the eastern native azaleas. His journeys covered many months and 27,000 miles, and resulted in a collection of some 8,800 herbarium specimens and several hundred living plants. Full and most interesting accounts of his studies and conclusions with respect to these species and their hybrids or intergrades were published at length in the Morris Arboretum Bulletin for January and April, 1955, with a condensed version in the 1957 Rhododendron and Camellia Yearbook of the Royal Horticultural Society of Great Britain. These studies and their review by Dr. Camp are the basis for the classification and description of these species and their intergrades in the Azalea Handbook published by the American Horticultural Society in 1952 and in The Azalea Book sponsored by that Society and to be published by D. Van Nostrand Company, Inc., in March of this year.
In addition, cytological studies of these species and intergrades, based on chromosome counts of the 1951 collections, have been published by Dr. Hui Lin Li of the Morris Arboretum, Philadelphia, Pennsylvania, in the American Journal of Botany for January 1957.
Rather than "shunned," I doubt that any group of rhododendron species has been as comprehensively and intensively studied in the field and from living plants, as these eastern natives. Dr. Skinner's studies were not limited to the Blue Ridge stations mentioned by Mr. Leach, but extended from Eastern Texas to Florida to New England on the coastal plain, the piedmont, the mountain ranges, and beyond. Numerous "melees" of species and intergrades outside the Blue Ridge Mountains were also discovered and have been reported. Some of these cover wide geographical areas, may often involve combinations of more than two species, and include individuals of differing chromosome makeup.
If Mr. Leach's wonderment extends merely to botanists having "shunned" publication of analytical or formal taxonomic findings based on the studies already made and looking towards modification of Rehder's conclusions in his Monograph of Azaleas, then it should be pointed out that, although these taxonomic findings are underway, the taxonomic recommendations may not be forthcoming for some time. While it is too early to say, such taxonomic findings are likely to include a redefining of R. alabamense , R. roseum , R. calendulaceum , and some other species so as to exclude the more evident intergrades; classification of the mixed populations; demonstrating the identity of R. bakeri and R. cumberlandense ; and reappraisal of the species status of R. oblongifolium and R. serrulatum in relation to R. viscosum ; as well as the varietal status of R. viscosum glauca , R. arborescens richardsoni , R. canescens candida , and others. First attention is being given to the Southern early populations rather than the later orange forms, and character combinations take time artificially to reproduce.
Mr. Leach further suggests that the American Rhododendron Society determine the condition of the Beadle manuscript on these azaleas and the possibility of financing the publication of it with the water color illustrations intended by Mr. Beadle to go with it. I have been given to understand by officials of the Smithsonian Institution and at Biltmore that Mr. C. D. Beadle becoming dissatisfied shortly before his death with the many new species he had created and described as the result of his field trips, destroyed his manuscript. His 2400 herbarium specimens are now with the Herbarium of the United States National Arboretum, as are the fine set of water color paintings of Mrs. Luella Porcher Johnson, both on permanent loan from the Smithsonian Institution. Mr. Beadle's diary still exists at Biltmore and data in it were used by Dr. W. Andrew Archer in clarifying notations of specimens. The lovely paintings and accompanying herbarium specimens have been on exhibition at Beltsville, Maryland, on several occasions in recent years. Publication of these paintings in color, with appropriate text based on the corresponding herbarium specimens, would, as suggested by Mr. Leach, be most worthwhile, and it is hoped funds for this can sometime be obtained.
I trust the foregoing information will be helpful to members of the Society interested in the tremendous variation among the native azaleas of the East and in their future horticultural development. Breeding work with them is now being carried on at the United States National Arboretum in Washington, D.C., at the Plant Introduction Garden, U.S.D.A., Glenn Dale, Maryland, and by individuals in the East, the Mid-west, and the Northern Pacific states.