Yamato Shakunage, Part 1
A Roundtable Discussion of Its Occurrence in Japan and Its Classification
Japanese Rhododendron Society
On Oct. 23, 1983, some of the members of the Japanese Rhododendron Society gathered in Osaka at
the Osaka City Trade Center to discuss a rhododendron known to them by the name "Yamato Shakunage."
It was loved by all for its flowers, foliage and its small size. Yamato Shakunage grows in the
wild only at high elevations of the Ohmine mountain range that includes so-called Kumano, three
mountains on Kii Peninsula and Mt. Yoshinoyama in Nara Prefecture. These areas are expected to be
included in the World Heritage by UNESCO in 2006. In their discussion, they attempt to classify
it within the subsection Pontica and to specify its location in the wild in the Ohmine
Mountain Range and the Ohdaigahara of Japan. The discussion illustrates the variation that can occur
within a rhododendron species and the delight these men found in this particular variant.
Since their discussion, Yamato Shakunage has been classified as Rhododendron degronianum ssp. heptamerum var. hondoense f. micranthum and is the close relative of Hon Shakunage, also discussed (see box). Yamato Shakunage is considered the high elevation type of R. degronianum ssp. heptamerum var. hondoense. In comparing the difference between Yamato Shakunage and Hon Shakunage, the former has by far more indumentum than that of the latter. It is almost as dense as that of ssp. yakushimanum. Also when compared with ssp. yakushimanum, while Yamato Shakunage has seven petals in its corolla, ssp. yakushimanum has five.
The moderator was Mr. Michihiro Shida, who also wrote the Introduction. The participants (from the Osaka Branch) were: Hiroichi Maehara, who had been in the Ohmine Mountain Range many times to study the rhododendrons in the wild with his sharp observation and who is one of the leading Yamato Shakunage researchers; Yohichi Nomura, Osaka branch president; Kiyoteru Kinoshita, former Osaka branch president; Tsuneo Kurosaki, Kyoto branch president; Kiyoteru Kosuga; and (from the Nara branch): Akira Fujiyama. Everyone listed here is an authority in various fields of Yamato Shakunage, such as in identifying the wild habitat of the plant in the Ohmine Mountain Range, in growing crosses of Yamato, and in cultivating the plant in pots. Representing the editorial office of The Rhododendrons as well as being moderator was Mr. Michihiro Shida.
The transcript of the discussion was published in the journal of the Japanese Rhododendron Society, The Rhododendrons, Vol. 13, No. 2, 1994.
Mr. Hideo Suzuki assisted in the preparation of the manuscript for the ARS journal and obtained the photos.
Photo by Michihiro Shida
Yamato Shakunage, white form.
Photo by Michihiro Shida
"Yamato Shakunage" - this word sounds truly refined and dignified. A rhododendron that grows wild on the high elevation of the Ohmine Mountain Range is called "Yamato Shakunage." It is also called "Ohmine Shakunage" or "Miyama Shakunage." There is still an untrodden primeval forest in the center of the Ohmine Mountain Range, which is one of the three sacred mountain ranges of Japan located deep in the Kii Peninsula.
Mt. Ohmine has been known as a training center of Buddhist priests since the Heian period. It is closed to women and it is a sacred spiritual mountain where the priest trainees and strolling monks have been trained. It must have been just the right training ground for those priests and monks whose lives are to practice austerities and asceticism. The Ohmine Mountain Range is blessed with rugged rocks towering above the clouds, precipitous cliffs, animal tracks, and dense primeval forests. There is even a theory that the Japanese wolves (ohkami), which are believed to have been extinguished during the Meiji period, may still exist. If indeed they still exist, the most likely place would be in the Ohdaigahara in the Ohmine Mountain Range.
Since the native ground for Yamato Shakunage is such a mysterious place there are many unknown aspects of this plant. Its leaves, flowers and the plant itself are rather small. The thin elegant leaflet of Yamato Shakunage has thick reddish-brown indumentum and its flower has seven thick petals of deep color. It has elegance of a different kind from Yakushima Shakunage (see box). Yamato Shakunage has been known and prized for a long time to some of the rhododendron lovers in its native region, Nara, and in the Kansai area in general. However, it seems to be only within the last ten years that this rhododendron has become known to rhododendron lovers throughout Japan.
Recently we had a chance to hold a discussion meeting on Yamato Shakunage, with an initiative from Kiyoteru Kinoshita, a member of the Osaka branch of the Japanese Rhododendron Society. Thus, finally, we could summarize the features of Yamato Shakunage.
We hope we can make clear to you what an interesting plant Yamato Shakunage is. Also we hope you have a chance to visit the Ohmine Mountain Range in Nara Prefecture during its blooming season, May or June, if you are a good hiker.
Mr. Michihiro Shida is Vice President of the Japanese Rhododendron Society and Editor of the Society's journal, The Rhododendrons.
Yamato Shakunage on Mt. Shakagadake, Japan.
Photo by Michihiro Shida
Yamato Shakunage on Mt. Shakagadake.
Photo by Yohichi Nomura
Moderator: Today we asked the members from Kyoto and Nara to gather at the Osaka branch building. I hope we all feel that we can discuss Yamato Shakunage freely.
First of all let us talk about the distribution of the plant, flora and elevation of its native area.
I'd like to ask Mr. Maehara to start. He explored the native area of Yamato Shakunage many times and knows the area very well.
Maehara: Regardless of elevation, from the bottom to the top, you can find Yamato Shakunage. It all depends on which mountain and which climbing path you take. For example, on Mt. Inamuragadake, if you climb up from Horiki Pass, all you can see is Yamato Shakunage. However, on Mt. Ohmine, Hon Shakunage grows at lower elevations. I like best the Yamato Shakunage growing on the Dainichisan on Mt. Inamuragadake. However, none is seen in the area a bit north of the Dainichisan, from Mt. Ohmine to Mt. Kofukendake. In this area short rhododendrons are growing. Along the Kamiwarabe Gorge we can see Hon Shakunage in the lower elevations. Then along the ridge to Mt. Gyojakandake, Yamato Shakunage is growing wild from place to place. I have not checked the lower elevation of this ridge. I believe the best seeds of Yamato Shakunage may be obtained from the top of Mt. Misen down to the west slope toward the mountain where the Daikoku Rock is located. On the Misen all the rhododendrons we see along the Misen River from the bottom to the top are Yamato Shakunage. No Hon Shakunage is found regardless of elevation on the Misen.
According ot Mr. Kurosaki, Yamato Shakunage grows on Mt. Myojyogadake also, but I have not been there yet. As you go down the ridge to the south from the Misen, Yamato Shakunage disappears again. On the top of Mt. Shakagadake at 1800m there is no Yamato Shakunage, though I have heard some good ones grow in the marsh area below. Also within the Ohmine Mountain Range, the more you go down to the south, the thinner the indumentum of Yamato Shakunage leaflets become.
Kosuga: There is a mountain called Mt. Shakunage to the south of Mt. Shakagadake, isn't there? How is the growth of Shakunage around there?
Maehara: I've heard there is one, but I've never been there. But, near the Twin Rocks, which are called Seitaka Doshi and Kongara Doshi, there are Yamato Shakunage with thin indumentum of the leaflets, almost like those in the Ohdaigahara.
By the way, there is a small-leaf cultivated Yamato which is often for sale. Among those cultivated along the Goshinsen, the railroad which runs from Gojyoshi to Shingushi, there is this nice looking small-leaf Yamato. Also one such Yamato comes from the Amatsuji area.
Moderator: At about what elevation is Yamato Shakunage seen growing wild?
Maehara: I think there is not much dependency on the elevation, but it would be safe to say it is above 1300m. I have seen wild ones at 1890m, the highest point I have seen it.
Moderator: Hon Shakunage is seen at its lowest elevation of 300-400m, but in general at about 800-1000m, but below 1000m, isn't it? Can we find Hon Shakunage growing on the same mountain as Yamato Shakunage below 1300m?
Maehara: Yes, we can. I heard that on Mt. Ohmine Hon Shakunage is also growing wild below Hachigome (the eighth stage of the climb). I believe the distribution of the plant changes with the course regardless of the elevation of the mountains.
Moderator: According to the assistant village master of Daito Village at the foot of Mt. Ohmine, in that region they seem to call Yamato Shakunage with thick indumentum "Hon Shakunage" and those without indumentum, which grow on lower elevations, "Nagi." When I had mentioned Hon Shakunage to him three or four years ago, he said, "Oh, you mean Nagi. Hon Shakunage (actually Yamato Shakunage) has dense indumentum on the back of its leaves and you have to go to relatively higher elevation to find them. All you find at the lower elevation will be Nagi." So, I have been thinking that perhaps the elevation makes a difference in the distribution of Yamato Shakunage. But now I hear it is not so. The difference in the growth does not depend on the elevation, but on which mountains and which valleys, doesn't it? I wonder why it is that way?
According to my experience when I went to the Ohdaigahara, all I saw there was Hon Shakunage with thin indumentum. I did not see anything looking like Yamato Shakunage's indumentum on the back. However, just one valley apart on the Ohmine Mountain Range, there grow many Yamato Shakunage. The elevations of the two places are not much different. How would you explain the difference in the kinds of rhododendrons?
Maehara: Though you did not find the Yamato at the Ohdaigahara, I have found one. But its indumentum on the back of the leaves is not as thick as those on the Ohmine Mountain Range. I sliced out some indumentum from the leaves and looked at them under a microscope. I found them to be branched, the same shape as those of the Yamato. So, it is the Yamato, though its indumentum is thin. Dr. Takenoshin Nakai describes it in the Dainippon Jyubokushi (a magazine of Japanese plants), Volume 1: "The leaves are shaped like those of Hon Shakunage and the flowers are small. This is called 'Yamato Shakunage.' It grows wild in Yamato Province." It seems to me that there are some Yamato Shakunage whose indumentum of the leaves are thin. On the other hand, according to Dr. Hisakichi Takeda, Yamato Shakunage is a strain of Tsukushi Shakunage (see box) whose indumentum is thick. So, as one way to classify the Yamato, it seems to be reasonable to divide it into two types, Nakai form and Takeda form.
Kurosaki: Is there any rhododendron with the indumentum on the back of the leaves at the lower elevation, at about 800m, of the Ohdaigahara?
Maehara: I don't think there is, though I really did not check the elevation accurately. However, on the Misen from the bottom to the top, most of them are the ones with thick indumentum.
Kurosaki: Is there any difference in the winter temperature between the two places? Is the Misen's temperature lower?
Maehara: I don't know. Perhaps only the natives of the regions may know. At any rate, no Hon Shakunage can be found along the courses to climb either Mt. Inamuragadake or the Misen.
Kurosaki: I climbed Mt. Myojyogadake and Mt. Shichimensan in the Ohmine Mountain Range. Here also, like Mt. Ohmine all we saw at about 800m was the one without indumentum, Nagi. The Yamato with indumentum begins to appear finally above 1000m. This made me think the elevation makes a difference in what kind of rhododendron is seen. But, is this not so?
Maehara: No, that is not true.
Moderator: I wonder if it all depends on how hard the winter is or if there are actually different kinds of the Yamato.
Maehara: As far as the size of the flowers is concerned, it becomes larger as you go south and becomes smaller as you go north. So, on the Odaigahara, many Yamato Shakunage with small flowers are seen.
Kurosake: Then, it may be that the elevation is not the only factor that affects the indumentum, I guess.
Moderator: I would like to hear about the flowers more in detail later, but for now I wonder if each of you can tell us about the experiences of going into the wild habitat of the Yamato.
Fujiyama: I have been living in Nara Prefecture for a long time and love to climb mountains, but I have not been to the wild habitat of Yamato Shakunage that much. However, I have been to the Ohdaigahara many times. There is a question as to which one is called Yamato Shakunage, but the one we call Yamato Shakunage, which has a thick indumentum on the back of the leaves, does not seem to exist there. Though there are many large groups of rhododendrons growing there, I did not see even once the type of Yamato with thick indumentum on the back of the leaves.
Maehara: It is growing mixed with others. So, it is hard to find unless it is searched for well.
Kinoshita: How about Mt. Hinodegadake in the Ohdaigahara? Are there any with the indumentum?
Maehara: Yes, there are some of those with thin indumentum over there, but as you approach Mt. Daijyadake, those with thick indumentum start to appear. There are none of those, however, around the immediate vicinity of the Gyusekigahara, where the path to the mountain branches out. Also, the more you go south, the more you see those Yamato with thick indumentum.
Fujiyama: Then, are there no Yamato with thick indumentum unless we go further south than Mt. Daijyadake?
Maehara: Yes, but along the path which goes to the Shiokaradani from the Gyusekigahara there grow some rhododendrons with thick indumentum though it is not as thick as those of the Yamato.
Fujiyama: It does not seem to be the type which is called Yamato Shakunage, does it?
Moderator: Which locations are the places where so-called Yamato Shakunage with the thick indumentum grows in clusters and where is it growing without much mix with Hon Shakunage?
Maehara: They are Mt. Inamuragadake and the Misen, as well as the ridge between Mt. Kofukendake and Mt. Gyohjakandake. At the lower elevation of this ridge, however, Hon Shakunage starts to appear, as you might expect.
Kurosake: Isn't there any Hon Shakunage with thin felt-like indumentum?
Maehara: There is as you guessed! There is one a little north of Mt. Otenjyogadake. It is the kind with a thin indumentum as if it were pushed hard onto the back of leaves.
Kurosake: How about those on the Suzuka Mountain Range? They have leaves which are brown on the back.
Moderator: What Mr. Kurosaki has just mentioned is Hon Shakunage on the Suzuka Mountain Range, which is north of the Ohdai Mountain Range. One such example is white-flowering Muranoshiro. It has dark brown streaks on the back of its leaves as if there were cracks on the leaves, which is a characteristic of the rhododendrons on the Suzuka Mountain Range. Actually, these crack-like streaks are indumentum. In our society magazine, The Rhododendrons, Vol. 1, No. 1, 1977, Keizo Kanazawa, who was then branch president of Mie Prefecture, published an article titled "Hon Shakunage in Mie Prefecture - Two Types and Their Distribution." In this article he says that the flora is divided in two with the geological Median Line which goes across the middle of the Mie Prefecture, and that type of Hon Shakunage may also be divided in two, one in the north and one in the south, across this line.
Characteristics of a typical Hon Shakunage in the north are the dark brown streaks on the backs of leaves, such as seen in the Suzuka Mountain Range, and no reddishness in the veins of new leaves.
The south type Hon Shakunage is the one you know well, those seen all over in the Ohdaigahara. The characteristic of this is that the veins of new leaves become clearly reddish in spring. Some of them become bright red, though the color fades away in summer or fall.
Kurosaki: Oh, yes, you mean the one with those red-veined young leaves. It is the southern type Hon Shakunage. I see. There are some people who call that either "Ise Shakunage" or "Ohdai Shakunage." The location of Yamato Shakunage is the same as that of the southern Hon Shakunage. I wonder if the Yamato actually is the southern type of Hon Shakunage?
Moderator: I believe it is a variety of that. This is my theory. Just like Yakushima Shakunage growing on the very top of the Yakushima Island has thick indumentum on the back of the leaves, the southern type Hon Shakunage grew more indumentum to adapt to the more severe climate and blistering winter of above 1000m elevation. I believe the Hon Shakunage which was originally growing at the low elevation expanded its habitat to the higher elevation and had to grow thick indumentum. And a variety of this Hon Shakunage is the Yamato.
Some say Yamato Shakunage is a variant or subspecies of Tsukushi Shakunage (see box), but Hon Shakunage also belongs to a main stream Tsukushi Shakunage. They are all "metternichii." I do not believe that the narrowly defined Tsukushi Shakunage, as the classification, grows wild on the Ohmine Mountain Range and the Odai Mountain Range, but that the wild habitat of Tsukushi Shakunage is in Kyushu and Shikoku. I think the ones on the Ohmine Mountain Range are a variant of the southern type Hon Shakunage growing at high altitude. Generally speaking, I think we can regard this Ohmine Mountain type indumentum as that of a typical Yamato Shakunage, though there must be some variation in the thickness of the indumentum.
Kinoshita: Namely, you say that the Yamato is a high altitude variety of Hon Shakunage, don't you? I think it is not true. The reason is that on the average Hon Shakunage has leaves wide at the tip, but that Tsukushi Shakunage has fusiform leaves. The leaves of Hon Shakunage are shaped like a Chinese soup spoon, a bit wide at the tip. However, when you look at the leaves of the Yamato, on the average, they are fusiform, though there are many individual differences in shape and even some of them are slightly wide on the tip. The Yamato's leaves look like scaled down Tsukushi leaves. The leaves of Hon Shakunage and the Yamato are quite different in shape. Also, I am a bit skeptical about the theory on Yakushima Shakunage. They say those at lower elevation of the Yakushima Island are Usage Shakunage, but as the elevation goes up the indumentum of the leaves becomes thicker. Consequently, they say the high altitude type of Usuge Shakunage is Yakushima Shakunage.
Though it's only my own interpretation, Yamato Shakunage is the result of the westerlies which carried the pollen of Tsukushi Shakunage. As you know, the higher the elevation, the easier it is for the wind to reach. As a result, near the top of the mountain more pollen should reach, and they were cross-fertilized and gained the unique characteristics of the Yamato. This should be true of the west side of the mountain also. Do you know which side of the mountains, the east side or the west side, has more Yamato Shakunage in the Ohmine Mountain Range?
Maehara: Not much difference, I think.
Kosuga: If you come close to Mt. Inamuragadake, at least, along both sides of the climbing pass, you will see only the Yamato growing in abundance. Also, it is so easy for the vapor to rise along the west side slope of that mountain.
Kurosaki: Is the elevation of the location about 1600 to 1700m?
Kosuga: I believe it is about that height, since it's above that Inamura camp.
Maehara: A bit below that, a little above Horiki Pass, however, there are some Yamato growing. From the Horiki Pass on, they grow among miscellaneous bushes. They grow more on the slope. Nomura: To the east of Mt. Inamuragadake is Mt. Kofukendake. Here there are hardly any Yamato growing on the south slope, but all on the north slope, besides, nothing in the lower elevation. They are growing all over on the north slope of the ridge about 30m wide at most. From Hichimendake to Shakagadake on these elevations between 1300m and 1500m there are mass growths of excellent form of Yamato Shakunage on the slope.
There is a place called Tamaoki Jinjya near the south edge of the Ohmine Mountain Range. Down south, the rhododendrons look close to Hon Shakunage, and their leaves are even larger than those of Hon Shakunage. The elevation here is just about 1000m. However, Mt. Kohyasan, where Kongobuji Temple is located, is at about 1000m, and it has rhododendrons whose leaves are close to those of the Yamato.
Maehara: There is a pass called Hinoki Toge on Mt. Gomadansan to the west of Mt. Ohmine. There are some Yamato growing there, though the indumentum of their leaves is thin. But on the top of Mt. Obakodake (1334m), a little bit northeast of Mt. Ohmine, Hon Shakunage grows. Also, on the south edge of Ohdaigahara, on Mt. Daijyagadake, there are some Yamato growing.
Moderator: According to Mr. Uchiatsume Noboru, my acquaintance who goes into the Ohmine Mountain Range all the time on account of his horticultural work, the wild Yamato's habitats, where they grow in clusters, are from the middle parts to the ridges of the Ohmine Mountain Range, where mountains of elevation from 1500-1800m lie side by side from the north to the south; namely, Mt. Ohmine, Mt. Inamuragadake, Mt. Chosendake, the Misen, Mt. Bukkyogadake, Mt. Myojyogadake, the Shichimensan, Mt. Busshogadake, Mt. Kujyakudake, Mt. Shakagadake, and Mt. Dainichidake. He said especially on Mt. Inamuragadake, Mt. Chosendake, the Misen, Mt. Bukkyogadake, and Mt. Myojyogadake the Yamato was abundant, and all that you see on Mt. Myojyogadake was the Yamato. But he said also that the best Yamato Shakunage are those from the Misen, Mt. Inamuragadake, Shakagadake and Mt. Chosengadake, as Mr. Kaekawa mentioned. He said in those areas he found many places where only the Yamato grow under the primeval forests of firs, hemlocks, and beeches as under-tree bushes.
Comparing Hon Shakunage with Yamato Shakunage, Hon Shakunage grows generally at a relatively lower elevation, below 1000m, while many Yamato grow above 1000m. Of course there are many places that they are growing together, and some are crossed species of rhododendrons. However, it is not always true that Hon Shakunage grows at the lowest elevation and the Yamato grows at the highest elevation, and the two species grow together in between on the same mountain. It is more often true that depending on which mountains, ridges, and marshes but regardless of elevation some of them are all covered with the Yamato, while others are with Hon Shakunage, according to my acquaintance. He told me the same story as Mr. Maehara. Relatively speaking, he said, regardless of the height, Hon Shakunage tends to grow on gentle slopes of the mountains where climbing is easy, while Yamato Shakunage tends to grow on rugged rocks or marshes wherever we could not reach easily. So, on the mountain where only the Yamato is seen growing, even at a low elevation - though it should be about 1000m - Yamato Shakunage is seen growing, though it has red leaves with thin indumentum, and at the higher elevation you can find good Yamato Shakunage with thick indumentum on the back of the leaves. Generally people treasure that high growing Shakunage with thick indumentum as true Yamato Shakunage, he said. The sizes of flowers and leaves of the Yamato have little difference, but a bit smaller than those of Hon Shakunage. But those Yamato growing on the rocks with no shade, where the sun is strong, have smaller leaves which have more curls in them as well as smaller flowers, according to him.
When all these observations are weighed, he said, he could not think Yamato Shakunage and Hon Shakunage are the same species. He believes either the Yamato is a completely different species from Hon Shakunage or a mutated species of Hon Shakunage by long exposure to the severe climates specific to the Ohmine Mountain Range.
Kurosake: Oh, it that so?
Maehara: I also think they are two different species.
Fujiyama: Mr. Maehara, you wrote somewhere that it is more proper to rename Yamato Shakunage to Omine Shakunage, didn't you?
Kinoshita: The area called Yamato within Nara Prefecture is such a wide area, isn't it? So, even for those people in Nara Prefecture, it is better to call the plant Ohmine Shakunage.
Maehara: Since the plant is listed in "Honso Zufo" (drawings of true plants) as Ohmine Shakunage from the old time, I believe it is more accurately called Ohmine Shakunage.
Moderator: I guess what you are saying is that it is more clear to call the plant Ohmine Shakunage, since it only grows naturally in the small area, the Ohmine Mountain Range. But, I like the sound of Yamato Shakunage. It has a good rhythm to it.
Kurosaki: Who did name Yamato Shakunage? A botanist?
Maehara: I think the first person to name this was Dr. Takenoshin Nakai. In his article in "Dainippon Jyubokushi," he listed the plant as "Yamato Shakunage, R. metternichii var. micranthum Takeda." Then later on, Dr. Hisakichi Takeda wrote about this plant as "Yamato Shakunage, R. metternichii f. micranthum Takeda." Namely, Dr. Nakai regarded the Yamato as a subspecies of Tsujushi Shakunage, while Dr. Takeda saw it to be one species of Tsukushi Shakunage.
Fujiyama: The scientific name, micranthum, means a "small thing or small flower," doesn't it?
Kurosaki: I believe so.
Moderator: Now how about the characteristics of leaves of Yamato Shakunage?
Kinoshita: There are a lot of individual differences, I think. Some leaves are small but nicely shaped and others are large. Flowers of the Yamato with large leaves are also large. By the way, this is also one reason why I believe that the Yamato is not the high-altitude Hon Shakunage with thick indumentum. Even if the leaves get large, they still maintain the fusiform. Leaves of Hon Shakunage are not so. This is why I tend to believe that the pollen of Tsukushi Shakunage flew over with the wind and mixed with those of the Yamato.
As I've just said, there are many types of leaves for the Yamato, from mini types to those almost like Hon Shakunage. There is a type of the Yamato whose leaves become large when it is grown at lower elevation, though its leaves were small at high elevation. Then there is a type where the size of leaves remains small even if it is cultivated at lower elevation. The shapes of leaves have also much variety, from fusiform to more round ones, to nearly like those of Hon Shakunage with widening tips. But all the leaves have reddish indumentum on the back of leaves. Also the sizes and color of flowers of the Yamato are rich in variety.
Kurosaki: How does the indumentum change from lower elevation to higher elevation?
Maehara: That all seems to depend on the course, but not on the elevation. However, when we cultivate the seed from the top, we can still get the indumentum which grows sideways, but we could not grow good ones from the seed at lower elevation.
Fujiyama: Even just looking at what I have at home, there are many varieties of leaves, from thin leaves which are no different from the wild to oblong-shaped (so-called koban shapeï¿½large gold coins used in our Samurai days) ones, round leaves, and fusiform leaves. Though I select the seeds from a good plant with leaves of good shape, many leaves with less perfect shapes come out when you grow it at home. Some leaves are not even shiny. The most beautiful type of leaf is the thin shiny leaf with a bit of sideways curls in it.
Maehara: Typical leaves of Yamato Shakunage are prolate ellipsoids with both ends pointing out, but some are of long needle or linear shapes and have tight inward curls. The cross section of the leaf is thick and second to Yakushima Shakunage. Also you will find the branched indumentum on the back of the Yamato leaves about the same length as those of the Yakushima and the Hosoba (see box), when they are examined carefully.
Moderator: Among those which belong t o the same fundamental species, Tsukushi Shakunage, as well as having thick indumentum the Tsukushi from Mt. Mimata has wide roundish leaves, but the Yamato has graceful streamline-shaped leaves like a young ayu (sweetfish). It is such a graceful plant, isn't it?
Kinoshita: Like Azuma Shakunage (see box) the Yamato and the Mimata are all small plants and just right for pot planting.
Maehara: New leaves of the Yamato have silver-white indumentum on the back and faint skin color or brown on the front side, which is similar to the coloring of new leaves of the Yakushima. Especially the contrasting colors of whitish indumentum and the red veins of the leaves are very striking. The size of the Yamato leaves in the wild is typically about 16 cm long and 2 cm wide. Of course, some are larger and some are smaller. I found some small ones 5-6 cm long and 1.2cm wide. The leaves of cross-fertilized plants with Hon Shakunage tend to be wider and the redness of the indumentum on the back becomes less red.
Moderator: I heard a story of how beautiful the Yamatos are when they show the reddish back as the wind blows on them at the locations, where they grow in clusters, from a native to the Yamato country, who often climbs the mountains. Certainly I love the chocolate colored and reddish dark brown color of the indumentum on the back of the leaves.
Kinoshita: I wonder if that color of the indumentum, the reddish brown or brick color, is unique to the Yamato.
Nomura: One Hon Shakunage from the Suzuka Mountain Range, which has reddish streaks on the back of the leaves, has leaves in dark brown, close to chocolate color. As the deepness of the color goes, this rhododendron has the deepest brown color. Many of the leaves of this Hon Shakunage and Yamato Shakunage have the shape of those of Yakushima Shakunage, which are slightly curled to the back, but some of them are V-shaped. The Yamato which I have at home has flowers whose outer edge is darker than the inside, which are shaped just like flowers of the Yakushima but whose color is much deeper. Besides, almost all of my Yamato's leaves are pointed at the tip, namely an ellipsoid shaping like a heart if I may stretch the point a bit. There are all sorts of leaves.
Maehara: I think the Yamato which has the most beautiful indumentum comes from near the Daikoku Rock on the Misen. It has a bright orange. However, when you bring it down to grow, the color fades, though on the mountain it is spectacular.
Kurosaki: The indumentum color on the back of leaves of Yakushima Shakunage is not anything to see, but for the Yamato's color I cannot find sufficient words of admiration. It is beautiful.
Moderator: It is because the Yakushima's indumentum is mostly light brown or camel color, isn't it?
Kurosaki: For the Yamato's red new leaves, there is no word to describe their beauty, is there? Also in the way the branches shape, the Tsukushi is no match for the Yamato.
Fujiyama: Though the indumentum is very beautiful, I like the redness in the new leaves. The Yamato as well as Hon Shakunage at a bit lower elevation all have red center veins in the new leaves, haven't they?
Moderator: Yes, you are right. It is a characteristic of Hon Shakunage and Yamato Shakunage which grow around the Ohdaigahara. Tsukushi Shakunage does not turn red, I believe, though I do not know all the Tsukushi. The Hon Shakunage from the northern Suzuka Mountain Range does not turn red either.
Nomura: Flowers do not always turn red even if the buds and stems are red. Generally deep colored flowers grow from whitish buds and stems. I tend to think that the whiter the leaf buds, the deeper the color of the flowers.
Part 2 is found in JARS volume 57 number 4.
Photo by Michihiro Shida
Rhododendron degronianum ssp. heptamerum growing at the
Rhododendron Species Botanical Garden in Federal Way, Washington.
Photo courtesy of the Rhododendron Species Foundation
Classification of Yamato Shakunage and Other Rhododendrons of Subsection Pontica of the Omine Mountain Range and the Ohdaigahara of Japan Japanese Name Former Classification Current Classification Yamato Shakunage R. metternichii var. micranthum R. degronianum ssp. heptamerum var. hondoense f. micranthum Hon Shakunage R. metternichii var. hondoense R. degronianum ssp. heptamerum var. hondoense Yakushima Shakunage R. metternichii ssp. yakushimanum R. degronianum ssp. yakushimanum var. yakushimanum Tsukushi Shakunage R. metternichii R. degronianum ssp. heptamerum var. heptamerum Azuma Shakunage R. degronianum R. degronianum Hosoba Shakunage R. makinoi R. makinoi Kurohime Shakunage R. x kurokimense R. x kurokimense (R. aureum x R. degronianum) Kibana Shakunage R. aureum R. aureum