JARS v52n3 - Down the Rhodo Trivia Trail

Down the Rhodo Trivia Trail
In Pursuit of West Coast Native Rhododendron Facts and Lore
Clive Justice
Vancouver, British Columbia Canada

After the Oban meeting in May 1996, the writer was able to spend two afternoons in the herbarium of the Royal Botanic Garden Edinburgh and had a look at all the herbarium sheets of Rhododendron macrophyllum held by the RBGE. There were none from Rhododendron Lake on Vancouver Island, and the last collection from the Upper Skagit River, from around Ross Lake, was in 1905. It was by John Macoun, the Dominion botanist who retired to Saanich in 1912 and died there in 1920. He is the gentleman with the full beard honoured on the 1970s 17-cent Canada postage stamp. (Remember when you could send a letter for that amount. Those were the days!) One of the herbarium sheets of R. macrophyllum from the Olympic Peninsula, Hood Canal area, was of a more recent date: 1955. The collector was Herbert G. Ihrig of Bainbridge Island, Wash. He was one of, if not the founder of, the Pacific Rhododendron Society that was active for a time during the '40s and '50s around the Puget Sound area. Most of the members were eventually absorbed into the Seattle and Tacoma chapters of the ARS. Herbert Ihrig was also instrumental in having the Pacific rhododendron legislated as the official flower of the state of Washington, even though, as Eastern Washingtonians complained, it grows only in the western one-third of the state. This plant partiality is much like B.C.'s official flower, the dogwood, Cornus nuttallii , which has an even more localized occurrence, growing only around the Georgia Straits basin.
David Chamberlain, 1996 ARS Gold Medal winner and head of the RBGE Rhododendron taxonomy team, indicated that RBGE herbarium could do with some more recent collection of R. macrophyllum . I promised to oblige, so in September 1996 on a return trip over the Hope-Princeton highway from Penticton I was able to stop and collect both seed for the ARS Seed Exchange and several representative botanical samples of Mr. Menzies' discovery from the Upper Skagit River location. This swarm of Pacific rhodos is several miles upstream from the larger swarm around the north end of Ross Lake. Located in a nicely developed Manning Park roadside attraction, consisting of a lay-by with a well presented descriptive/interpretive display and a 10-minute walkabout among some large rhodo shrubs that are shaded by small sized but old second growth hemlock and Douglas fir.
In early October 1966 I also made a similar collection of seed and branches with leaves and seed pods of the Vancouver Island, Rhododendron Lake, rhodos. All were put in the plant press for drying and then labeled and delivered to Gerald Straley at the UBC Botanical Gardens who kindly offered to consign them through botanical garden channels to David Chamberlain in Edinburgh. There they would be mounted and placed in the RBGE herbarium along with the thousands of other sheets of species rhodos collected by Forrest, Rock, Kingdon-Ward and all the other rhodo greats. I also included seed from both locations so the RBGE gardens will be able to have living plants from these two most northerly Canadian occurrences of R. macrophyllum .
Now a bit of trail end trivia. The Upper Skagit rhodos are 10 minutes of latitude farther north than those at Rhododendron Lake. The mainland ones are at 49°1 5'N,121 °45W, while the Vancouver Island rhodos are 49°5'N, 124°15' W. That's about 20km.

The California Connection
US Highway 199 from Crescent City, Calif., to Grants Pass, Ore., angles northeast along the western flanks of the Siskiyou mountains. It begins just north of this northern most Californian coastal city and winds through the large coast redwoods of Jedadiah Smith State Park and Smith River Recreation Area and then follows the middle fork of the Smith River and crosses the 42° latitude line into Oregon. This 40-mile section of highway through forest and along rugged rocky river canyon goes through a very diverse forest, but constant throughout are two of Mr. Menzies' 1792 discoveries, the Douglas fir and, at the highway edges as a regular almost continuous part of the under storey, R. macrophyllum . The rhododendrons particularly are on the north facing roadside forest edges along the river canyon, while all along the steep south and west facing slopes was another of Mr. Menzies' tree discoveries, Arbutus menziesii , the Pacific madrone.
It was mid November, and I stopped to collect seed. Most, however, were long since dispersed from capsules spread star-shaped even in the rain. Several branches cut for drying and pressing for the RBGE herbarium had 9 inches of current and previous year's growth and flower buds on almost all the terminal leaf whorls. What was most surprising was the accompaniment of trees and shrubs to the rhodos in this south roadside forest edge. The hillside forest was mostly Douglas fir, but out front there was incense cedar; Lawson's false cypress; Western white, lodgepole, Jeffrey, knobcone and whitebark pines; canyon live oak; golden chinquapin (the latter along with Lawson's false cypress and Western white pine were David Douglas' discoveries). Among the shrubs there was the shrubby tanoak, two varieties of manzanita, the hairy and common manzanita, look alike stems of Arbutus , along with the evergreen huckleberry. The only thing good about the broken rocky soil was that it was well drained. The rhodos seemed to be outcompeting the rest, as there were 2-and 3-year-old leggy ones all around. The only plants seeming to give the rhodos a run for the money were the evergreen huckleberries and golden chinquapin.
Most all of the rhodo books give R. macrophyllum pretty short shrift indicating its occurrence range "California to British Columbia." We know its northern limit in B.C. (49°15'N), but since California extends through almost eight and a half degrees of latitude from 32°30+' at the Mexican border to 42° at the border with Oregon (675 miles), just stating California is not enough to answer the trivia question: where is the southern limit of macrophyllum's range in California? One helpful clue is that R. macrophyllum in California is associated with the Coast redwood forest, so you will find it growing in the deep cool shade of the world's tallest conifer. Except for a couple of breaks where this forest type doesn't occur, around the Tomales Bay-Point Reyes, city of San Francisco and peninsula, and south a bit, the redwoods are almost continuous from 42° all the way to latitude 36°. If memories of 45 years ago serves this correspondent right, you will find R. macrophyllum in Henry Cowell Redwoods State Park (lat. 37°) located just north of Santa Cruz along the San Lorenzo River and at Big Basin Redwoods State Park half a degree north at the boundary of Santa Cruz County with San Mateo County. You will most certainly find it in Muir Woods National Monument (lat. 38°) on the western slopes of Mt. Tamalpias in Marin County just north of the Golden Gate Bridge.
In 1789 when Capt. Collnet in Prince of Wales visited the Spanish mission at Santa Cruz he had a surgeon botanist on board who went ashore to do some botanical collecting. He collected, pressed and mounted a branch of the tree that he found there. When he got it back to England, David Don, the botanist at Kew, said, "I know what that is. We have one of those already growing in the garden (Kew). It's the swamp cypress, Taxodium distichum , from Florida." The surgeon botanist was Archibald Menzies. This tallest of conifers lay unrecognized and misclassified botanically for 50 years. Eventually it was given a genus name honouring an obscure Florida Indian [ Sequoia ] and recognition that this magnificent and unique tree was indeed evergreen with the very ordinary species name sempervirens . Now, that's a whole trivia story for another time.

The RBGE Record
After the ARS Oban meeting this correspondent was able to pick up the most recent publication of the RBGE titled: The Genus Rhododendron, Its Classification & Synonymy by David Chamberlain, Roger Hyam et al. In this slim paperback volume there is a section titled "List of Accepted Names in Their Biological Recording Units." It seems these "BRUs" are various geographical areas with the list of the rhodo species found there; for example: BHU-Sl (India-Sikkim) has 35 Rhododendron species, 14 subspecies (ssp.) and 3 varieties (var.) listed; for CHC-YU (China-Yunnan) there are 12 species, 3 subspecies, 7 varieties; while under the listing BRC-OO (Canada-British Columbia) there is a short list of 4 species, no subspecies and only 1 variety. Up until now there was thought to be only three Rhododendron species resident in our province. These three are RR. macrophyllum , lapponicum , and albiflorum . The variety R. albiflorum var. albiflorum is the one variety and is the one that is growing in the RBGE. The fourth species is R. groenlandicum . This plant has undergone what is known botanically as "taxonomic revision," moving from the genus Ledum into Rhododendron . However, this is not the real trivia. We have known for some time that Labrador tea is a rhodo. The important trivia is that there are two other ledums cum rhodos in B.C. So with Ledum glandulosum and L. decumbens joining the rhodo ranks, B.C. now has six rhodo residents, not four. This will still put us ahead of WAS-OO (United States-Washington) by two, as the Pacific rhodo state lacks the far northern (above lat. 58°), R. lapponicum and R. decumbens . A revision to include these two new B.C. rhodos has been promised by RBGE when the monograph is updated, but your correspondent was assured that they are already in the RBGE computer data base. Unlike the Pacific rhododendron, the Western azalea, R. occidentale , never made it across the wide mouth of the Columbia River into coastal Washington and B.C. However, it did make it to England in 1850 and bloomed first in James Veitch's nursery seven years later. From there, it immediately came into the gene pool of species azaleas that Veitch, Anthony Waterer, Koster and other used to create a distinct group of delicately coloured fragrant hybrids with beautiful sounding superlative names such as 'Delicatissimum', 'Exquisitum', 'Graciosum', and 'Superbum'. Veitch's collector, William Lobb, who had brought back the Western azalea seed to Veitch's Exotic Nursery, King's Road Chelsea, had a few years earlier, in 1843, come home with the David Douglas discovery of 20 years before; a Northern California rhododendron that Sir William Hooker had promptly named R. californicum . Sir William had not bothered to compare it with that of Archibald Menzies' Discovery Bay collection 35 years earlier to see if it was the same species, most probably because the great botanist saw no need to make a comparison, as over 1,000 miles separated the two collection sites, Douglas' near San Francisco and Menzies' on the edge of the Strait of Juan de Fuca. With that distance it had to be a different species and another entry for my Flora Boreali-Americana. Most collectors, compilers and conveyors of plants are by nature splitters not lumpers. Veitch raised R. californicum and in 1855 exhibited it in flower for the first time at the Crystal Palace, Sydenham. Veitch's comments, as recorded by Sir William, the editor, in the July 1855 Botanical Magazine: "A delicate pink kind of rhododendron, very different in appearance from those of the eastern mountains of America, or from any we have in cultivation." This prestigious venue, Sir Joseph Paxton's great glass hall built for the 1851 Exhibition, and the low key description, however, was overshadowed by another rhodo. The show stealer that year was the large bright scarlet flowers of the "stove house" Javanicum: R. brookeanum from the island of Borneo that was exhibited alongside the "delicate pink" in Veitch's Chelsea Nursery exhibit that June. This was a spectacular addition to the then popular demand for new and exciting plants for the conservatory and stove (hot) houses of the estates and country houses of England. Called "Javanicums" as most came from the island of Java in the then Dutch East Indies, R. brookeanum was named for Sir James Brooke, Rajah of Sarawak, North Borneo.
Like the Western azalea, R. brookeanum was quickly put into the gene pool to produce such hybrids as 'Ne Plus Ultra' (scarlet and yellow), the princesses 'Princess Alexandra', 'Princess Beatrice', and 'Princess Royal' (blush white, light yellow suffused with pink, and light rose pink respectively), 'Queen' (white with cream centre) and 'Thetis' (tawny yellow). This latter hybrid name was not for Thetis Island, one of the Gulf Islands in Georgia Straits, named for H.M. frigate Thetis, 36 guns, 1,450 tons, on this Station (Esquimalt) 1851-53, but for Thetis, the mother of Achilles, he of the heel. Most of the Javanicum hybrids of the mid and late 19th century have long gone with demise of the heated glasshouses through two world wars. However, your correspondent photographed R. brookeanum on Mt. Kinabalu and notes there is a named selection called 'Mandarin' in cultivation.
This trivia trail excursion that started with Biological Recording Units and genus Ledum transfers would not be complete without reference to two BRUs that make up the rest of our West Coast. The BRU for ORE-OO (United States-Oregon) lists only one Ledum transfer, the south of 49° Labrador tea becomes Rhododendron neoglandulosum (gland splitting?), while R. albiflorum var. albiflorum , R. macrophyllum and R. occidentale make up Oregon's four native rhodos. The BRU for CAL-OO (United States-California) lists four rhodos, two of which were previously ledums. The gland splitter Labrador tea, R. neoglandulosum and R. (Ledum) columbianum , along with the two originals R. macrophyllum and R. occidentale . The previous trivia trail traced the range of the Pacific rhodo from Parkville/Skagit in B.C. to Santa Cruz. What about the range of the Western azalea? We know it didn't get north of the Columbia River and occurs all along the Oregon Coast, but how far south does R. occidentale grow in California? The short answer: all the way. From State Coach Hill in California's most northerly county, Humboldt, at the Oregon border latitude 42° all the way south in the coast ranges to the mountains around San Diego, just shy of latitude 32°. The Western azalea also occurs in the Sierra Nevada in eastern California. This correspondent collected seed and photographed it around the stream and moving water areas near the world's largest living objects, the big-trees, Sequioadendron giganteum , and collected seed for the ARS Seed Exchange from pure white flowered form of R. occidentale from a mountain stream edge named Peckinpah Creek bordering Peckinpah Meadow close by Peckinpah Mountain, just up from North Fork, Calif., N lat. 36°30"-119°W longitude. The aforementioned geographic features being so named for a settler, the grandfather of your correspondent's spouse of 48 years. The R. occidentale on Stage Coach Hill story is for another time.

Clive Justice, a landscape architect and a member of the Vancouver Chapter, is a frequent contributor to the Journal. His most recent article appeared in the Spring 1998 issue, "Tracking Mr. Fraser's Rhododendron North of the 60th Parallel."