by Art Guppy
This article was published in the Winter, 2006, issue of bulletin of the Alpine Garden Club of BC, with several photos by others. The attached photos were taken by the author, some after this was published.
Two recently named Erythronium, E. quinaultense and E. elegans, could well be described as western North America’s most unusual Erythronium, and the latter species could well be the most enigmatic. As I have been observing and reading about the two species almost since they were named, and in 2005 I collected seed of both in the wild and donated it to the seed exchange, it seemed I should pass along some of what I have learned about the plants, so that those who plant the seed will know what to expect from them. They may be in for surprises.
E. quinaultense was named in 2001 by Geraldine Allen of the University of Victoria. It is a tetraploid species (2n=48) which evidently originated in the fairly distant past from the hybridizing of E. montanum and E. revolutum accompanied by doubling of the chromosomes, and it has traits intermediate between those of the two parent species. The flowers are close to white but the tepals are pink along the edges and at the tips. The leaves could be described as plain green except for a trace of mottling which is most apparent as pale lines along the veins. The species is found in a fairly large forested area north of Lake Quinault on the southwestern edge of the Olympic Mountains, Washington. The plants I saw when I was collecting seed were in fairly open old-growth coniferous forest in habitat that varied from fairly moist near a stream to moderately dry on higher, sloping ground.
I have been able to observe the plants in my garden for several years, as Geraldine Allen very kindly gave me seeds in 1998. They are robust garden plants, but I am a little unsure of the flower colour in cultivation. I moved my garden from Metchosin to Duncan in 2004. In my old garden the E. quinaultense flowers were almost white with rather inconspicuous pink markings on the tepal edges and tips. Because at Duncan I needed to build raised beds to get my plants above a soggy clay soil, it was March, 2005 before the E. quinaultense bulbs were planted. They flowered very well in spite of the late move, but the flowers surprised me by being fully pink. That unexpected (and delightful) colour change may have been caused by their getting more sun in their new location, but I suspect it was the response of the plants to the stress of being moved in March. I am waiting with interest to see the colour of these chameleon flowers next spring.
E.elegans is the problem species. It was named and described by Paul Hammond and Kenton Chambers in 1985. Its habitat is mainly on the summit area (about three square miles) of Mt. Hebo (945m/3100ft) in northwest Oregon, but there are also small populations on two mountains 15 and 25 miles to the south of Mt. Hebo. On Mt. Hebo it is found in open grassland, in brushy areas, and in coniferous forest, all of which seem fairly well-drained. It was described by Hammond and Chambers as having flowers ranging in colour from pure white to deep rose-pink, with the majority pinkish white, and as having leaves varying from plain green to heavily mottled. The stamen filaments were described as varying from being very slender to being moderately wide at the base. The plants with rose-pink flowers and heavily mottled leaves were described as being very rare in the population. The authors suggested that the pink colouration in the flowers and the mottling of the leaves may have come from introgression from E. revolutum at some time in the fairly distant past, but they did not believe the species was of hybrid origin. They believed that E. elegans was related to E. montanum, but that it differed from that species in having leaves that tapered gradually to short petioles, whereas E. montanum has leave that taper abruptly to very long petioles, and that it differs in having flowers that are pendent, whereas E. montanum has flowers in a horizontal position.
It is evident that Hammond and Chambers had not seen the E. montanum on San Juan Ridge on Vancouver Island, as in that location the E. montanum commonly have the characteristics which they thought distinguished E. elegans. The characteristics which are usual for E. montanum in subalpine meadows seem to be simply an adaptation to the need to hold the leaves and flowers above the mass of competing vegetation usually present in the meadow habitat. On San Juan Ridge the Erythronium are generally under tall Vaccinium shrubs where there is little vegetation near ground level, so they tend to have leaves that taper gradually to short petioles, and the flowers are generally nodding, at least when they first open. On Mt. Hebo the Erythronium are in open habitat or under shrubs or in the forest, and consequently they have little competition from low vegetation, and they behave like the E. montanum on San Juan Ridge. There is a very instructive photograph of E. montanum on page 113 of Bulbs by Roger Phillips and Martyn Rix. The photo was taken on Mt. Rainier, so the plants probably are genetically the same as the thousands in the mountain meadows, but they have the characteristics of the Erythronium on San Juan Ridge and Mt. Hebo. The reason is obvious: the Mt. Rainier plants in the photo are in scree-like conditions where there is no competing vegetation.
At the time the paper naming E. elegans was published, I had been growing Erythronium in my garden and observing various species in the wild for a number of years, and I was beginning to know the genus rather well. When I read the description of E. elegans, I immediately saw that if one thought of plants at one end of the range of variation described for the species, their traits would be those of the E. montanum on San Juan Ridge, and consequently I formed an hypothesis that the population on Mt. Hebo was really a hybrid swarm of E. montanum and E. revolutum. The difficulty with my hypothesis was that at that time there was no evidence E. montanurn could cross with E. revolutum. Indeed, E. I. Applegate, in his 1935 monograph on the Erythroniurn of western North America, had placed the two species in separate sections, which made it seem very unlikely the two could hybridize. Fortunately I had both E. revolutum and some San Juan Ridge E. montanum in my garden, so I proceeded to cross them, using two robust E. revolutum as seed parents. From their seeds I raised over 50 hybrids, which made a marvelous display in my garden, for they were very vigorous plants, and eventually most of them had 2 or 3 flowers. The offspring of one of the seed parents ranged in flower colour from very pale pink to deep rose-pink, while the offspring of the other parent were all various shades of pale pink. They all had narrow stamen filaments, though they were wider than those of E. montanum, and all had plain green leaves. They seemed very nicely to support my hypothesis of the Mt. Hebo population being a hybrid swarm, but I soon had to revise the idea, for I belatedly learned of an important new discovery on Mt. Hebo.
Shortly after the paper naming E. elegans was published, two researchers made chromosome counts from a small number of the Mt. Hebo plants. The counts were tetraploid, and were the first tetraploid counts for western North American Erythronium. Some years later, Geraldine Allen, in her paper naming E. quinaultense, reported that in connection with her research on that species, she had made a chromosome count from an E. elegans plant that confirmed the tetraploid counts made by the earlier researchers. She suggested that in all probability the Mt. Hebo tetraploids originated in the same way as had E. quinaultense; that is by the hybridizing of two species, probably E. revolutum and E. montanum, accompanied by doubling of the chromosomes. It is to be noticed that her hypothesis departed from the opinions expressed in the paper by Hammond and Chambers in that it meant that the Mt. Hebo species was of hybrid origin, and it indicated that E. montanum probably had been present on the mountain. If it was present in the past, it would not be surprising if it were present today.
Years ago I raised two E. elegans from seed from Mt. Hebo. One had a pure white flower, except for the touch of yellow at the centre; and its leaves were plain green. The other was identical except it had a faint tint of pink in its tepals. Both had slender stamen filaments. As I also had some E. montanum from San Juan Ridge, I soon noticed that there was no significant difference between the two taxa, except for that slight tint of pink in the flower of one of the E. elegans. I had revised my hypothesis to include a large number of tetraploids in the population and to include Geraldine Allen’s suggestion that those tetraploids originated from the hybridization of E. montanum and E. revolutum, but I continued to believe the population must include the remnants of a hybrid swarm. Logically, after all, those tetraploids would have emerged in a hybrid swarm. With taxonomic matters, I follow what I call the “duck principle”. If it looks like a duck, walks like a duck, swims like a duck, and quacks like a duck, it is a duck. Consequently, I felt sure the white-flowered plant I had raised from Mt. Hebo seed must really be an E. montanum, and its companion plant with the faint tint of pink in the tepals must be the product of several generations of hybridizing from a cross with E. revolutum, with backcrossing to E. montanum. An article by Brian Mathew in the September, 1998 Quarterly Bulletin of the Alpine Garden Society added to my feeling of conviction. In the article Brian Mathew mentioned that with the E. elegans plants he had grown, the foliage was plain green and the flowers pure white. To me that description suggested that his plants were probably really E. montanum, and also that E. montanum may be rather common on Mt. Hebo.
My curiosity was aroused, and in May, 2005 I visited Mt. Hebo to see for myself. Unfortunately, my timing was bad, as spring had come early in that region, and most of the Erythronium bloom was finished. However, my main reason for coming to the mountain was not finished. In the shade of forest trees there were still white-flowered Erythronium at the peak of bloom. I inspected those plants very carefully. The flowers were pure white except for the touch of yellow at the center; the stamen filaments were slender, though possibly a tiny fraction of a millimetre wider than those of E. montanum, and the leaves were plain green. To me those white-flowered plants are E. montanum, and they are evidently fairly common on the mountain.
The E. montanum of Mt. Hebo differ from the E. montanum of San Juan Ridge in two ways: the stamen filaments seem very slightly wider, and the plants are easier to grow in a garden. Both differences are explained by the E. montanum of Mt. Hebo and nearby mountains very probably having been isolated from other populations of the species for thousands of years as glaciers melted and the climate warmed. The cool, moist winds off the Pacific would have made it possible for them to survive and adapt to the changed conditions. The difference of stamen width is too slight to be significant, and could easily be the result of random variation over a long period of time. The fact that they are better adapted to garden conditions than the same species on San Juan Ridge is explained by the difference of latitude. A lower latitude has much the same effect on plants as a lower altitude.
The apparent existence of numerous E. montanurn in the Mt. Hebo population reinforces my belief that the remnants of a hybrid swarm could still be there, but on my visit in May I was too late to look for any plants close to E. revolutum. However, the paper naming E. elegans provides very strong evidence that E. revolutum has been present at least until very recently, for it mentions that “some local colonies consist largely of mottled plants”. A single colony with mottled leaves could be explained as being the result of a second hybridization event producing a different group of tetraploids, but it seems virtually impossible that there could be several colonies of tetraploids with the same conspicuous difference from the main group of tetraploids. Surely the most probable explanation for those colonies of plants with mottled leaves is that E. revolutum plants, or plants very close to being pure E. revolutum, formed the nuclei of the colonies with mottled leaves, and those colonies would be the diploid remnants of a hybrid swarm. Hammond and Chambers were unaware that tetraploids made up a large part of the population when they wrote that the “majority of individuals have a pinkish-white perianth”, but it seems likely they were describing what were later found to be tetraploids. Actually no one has written a detailed description of the tetraploids, but we can piece together a description that is likely to be accurate. In the key to related species in the paper naming E. quinaultense, the tepals of E. elegans are described as more or less “white to pinkish, the outer ones generally more strongly colored, especially on the outer surface”. The Spring, 1992 ARGS Bulletin on page 123 has an excellent photo of an E. elegans taken on Mt. Hebo. The flower has the inner tepals white or almost white, and the outer tepals are a pale pink on the inner surface and a darker pink on the outer surface. That photo perfectly fits the description given in the key mentioned above. The photo shows leaves that are almost plain green but have pale lines along the veins. Probably we now have an accurate description of the tetraploids on Mt. Hebo, and it seems clear the colonies with mottled leaves are a different taxon, almost certainly the remnants of a diploid hybrid swarm.
Not only do we now have a description of the tetraploids, but I believe we have a description of the entire Erythronium population on Mt. Hebo, and there is a reasonable hope it is right. It is made up of a large number of tetraploids with inner tepals that are almost white, and contrasting outer tepals that are pale pink on the inner side and darker pink on the back. These plants have leaves that are almost plain green, but have pale lines along the veins. The second largest group in the population consists of E. montanum that are well-adapted for growing in a garden. The third group, probably quite small and scattered, is made up of the remnants of a diploid hybrid swarm, with possibly an occasional E. revolutum. That description of the population is an hypothesis, and it is to be hoped that before long someone will do a proper study of the population so we can know if it is correct.
In future years there are certain to be many questions raised about this enigmatic population. At present the entire population is called E. elegans, but that seems very unlikely to be acceptable for very long. If I had them in my garden, I would label any that look like the photo in the Spring, 1992 ARGS Bulletin as E. elegans, and the ones with white flowers and plain green leaves, I would label as E. montanum. The others I would label with question marks.
Judging from the floras that have been published for the Pacific Northwest during the past half-century, there are likely to be taxonomists writing in floras for this region in the future who will make changes to the two species in the title of this article. In the past we found in Vascular Plants of the Pacific Northwest, Part 1 (1969) by C .L. Hitchcock, et al that the former species E. idahoense had been lumped with E. grandiflorum as var. candidurn, and the former species E. nudopetalum had been lumped with E. grandiflorum as var. nudipetalum. (Notice the change of spelling.) Geraldine Allen, writing in two recent floras, has lumped E. howellii as merely an unnamed form of E. citrinum. If that trend toward lumping continues into the future, E. elegans and E. quinaultense are likely to be lumped as one species because they are almost identical except for the arrangement of pink in the flowers. It would be anybody’s guess which name would survive. It could be E. elegans because that name was given first, or it could be E. quinaultense because it is ambiguous what plants were given the name E. elegans. I suppose I am somewhat of a splitter, as I am undecided whether the changing of E. idahoense and E. nudopetalum to varieties of E. grandiflorum was justified, and I feel strongly that E. howellii should continue to be recognized as a species. I want more time to study the population on Mt. Hebo before I form an opinion on E. elegans and E. quinaultense, but I lean toward keeping them as separate species.