The Origin of the Native Rhododendron californicum (macrophyllum)
by C. I. Sersanous, President
On Sunday, June 17th, the American Rhododendron Society held a gathering on the slopes of Mt. Hood, and following the picnic the meeting adjourned to Laurel Hill, famous in the Oregon pioneer days of 1845. Here in a talk made by the President, an attempt was made to trace the origination of the native rhododendron, as to how it came to be in this Mt. Hood area.
In writing such a rather sketchy history I start the first order of those things which came into being by starting at the present, in which I stated that these rhododendron on Laurel Hill were not planted by man and it is questionable as to how long they had been with us. I feel very humble in speaking upon the origination of this plant when I attempt to invade the field of recognized botanists of America and Europe. It is evident that these Rhododendron were here in 1845, the year of the start of immigration from the East to the Oregon territory. It is thought that Laurel Hill was named from the native rhododendron growing here at that time, and the name of Laurel Hill undoubtedly came from the plant, for in the East the rhododendron is often referred to as Mountain Laurel, and especially so the Kalmia species. It may or may not have been in bloom at that time, but the foliage of the native rhododendron is very similar to that of the Kalmia latifolia.
The next in order is that the Rhododendron californicum was discovered near Port Discovery, Washington by Archibald Menzies, a botanist, on May 4, 1792, as related in Menzies Journal of Vancouver's Voyage April to October 1792. Menzies describes the californicum as being white. George Don in his General History of the Dichlanydeous Plants used the name of macrophyllum in 1831-38. Others have described macrophyllum as being rose pink. In parts, especially the Southern part of Oregon, has been found the white form Menzies call californicum. One of our members, R. M. Bovee, now Vice President of the American Rhododendron Society, found this white form seven years ago in Southern Oregon, removed the plant and has grown considerable quantities of this particular form over a period of years. There is considerable confusion as to whether the native rhododendron is californicum or macrophyllum, and there of course could be different forms without any particular relation such as evident in the sub species.
In the Handbook of Rhododendron published by the University of Washington Arboretum Foundation in 1946 there appears an article contributed by C. L. H., which article starts as follows.
"I have been asked to express an opinion as to the correct name of the State flower of Washington. Is it Rhododendron macrophyllum or (shades of the Los Angeles Chamber of Commerce!) is it Rhododendron californicum?"
Certain references are made to Menzies, Hooker, and G. Don, also to the propriety of botanists following a set of rules or laws known as the International Rules of Botanical Nomenclature. Description of R. macrophyllum is given, as published by G. Don in the General History of Dichlanydeon Plants in 1834. Don states that it is a native of the North most coast of America where it was collected by Menzies. Don describes the flower smaller than those of Rhododendron maximum, white. You will note above that in Menzies Journal, he described R. californicum as being white.
Sir William Jackson Hooker, references-Bot. Mag. T 4863-1855, states that californicum was introduced by William Lobb in 1850. He describes it further as a native of California, Oregon, and Southern British Columbia. He states further it may be considered as the Western representative of Rhododendron catawbiense, from which it is distinguished by its more erect growth and differently colored flowers and smooth flower stalks, a rare plant in British gardens but quite hardy. There are several varieties of this species in cultivation. "Rhododendron macrophyllum is possibly one of these."
Clement G. Bowers, a member of the American Rhododendron Society, of New York, in his book on the "Origination, Cultivation, and Development of Rhododendron and Azaleas" (1936) gives a description of the californicum as the flowers being of rosy purple or pink, paler toward the center, spotted yellowish or brownish, rich carmine in bud, margins crisped or waved, grown on the mountains of California, Oregon, Washington, and British Columbia, a western representative of Rhododendron catawbiense. A form with smaller white flowers, smaller capsules, and larger more pointed leaves is sometimes distinguished as variety macrophyllum.
I have digressed somewhat from the origination of the plant, and from the point of discovery of Menzies in 1792, there seems to be meager information as to the origination. However, in the discovery of the Kalmiaopsis, discovered by Mr. and Mrs. John H. Leach of Portland, June, 1930, and called Kalmiaopsis leachiana, we strike a lead which indicates that the native rhododendron came with the Tertiary Age. In a description of the plant in the Journal of the Arnold Arboretum at Harvard University, by Dr. Alfred Rehder, he stated that the new genus is apparently like Loiseleuria and Rhodothamus, a phylogenetically old type of the Tertiary meaning the Tertiary Age. This takes us back to a period when there was no time and of course before man. The Tertiary Age was part of the Cenozoic Age, and while it is called the modern life era, it happened approximately fifty-five million years ago, and during this time was the BIG ICE PERIOD in which the flow and recession happened on four different times. It has been 25,000 years since the ice left and during this Tertiary Period was the time of great geological and geographical changes, at which time the Alps, Himalayas, Caucus and other mountain ranges were created, including the Cordilleran system from Alaska to Cape Horn. Various parts of the globe shifted, new continents were formed and then came the warm period, which we are now in. About that time or about twenty five thousand years ago wild flowers appeared, so did Birch trees, Walnut, Elm, Oak, and Maple, and mammals dominated the land.
In a letter from Dr. Robert Moulton Gatke, a member of the American Rhododendron Society and a director and publisher of the yearbook, he interviewed Dr. Morton Peck, who perhaps is the last word on the wild flora of this state. Dr. Peck assumes that the native rhododendron, like all rhododendron, had its origin in the mountains of Asia and is circumpolar; our native rhododendron following the mountains as far South as Central California, and the East Coast species such as the catawbiense and maximum following the mountains of that region to the south.
I will now advance another theory that in the upheaval of this ice age that these seeds from Asia have been brought about through movements of ice and were deposited on the North American Continent by the receding glaciers of this age inasmuch as there came a growth of trees and flowers during the ice recession.
I have attempted to give you some ideas as to the origination of the native rhododendron. It is something to think about on this day of paying our respects to a beautiful and gorgeous plant, one of our God-given attractions to our heritage and posterity of this State of Oregon.