Plant Encyclopedia

Cypripedium tibeticum, a highly variable Chinese lady slipper orchid


One of the most startling of the Chinese lady slipper orchids is the highly variable Cypripedium tibeticum. Superficially it is similar to the more widespread C. macranthos, and indeed some forms of that species, especially those known as hoteiatsumorisou in Japan, are near dead ringers for the more spectacular large flowered forms of C. tibeticum from Sichuan, China.
In a similar way C. tibeticum is as variable as the North American C. parviflorum, making its taxonomy problematic. As a result it has been given any number of names – the bulk of those considered invalid by most authorities. Hopefully in this article I will at least help clarify what plants have been found in nature.

 

Cypripedium tibeticum is a herbaceous, perennial, terrestrial orchid of high mountain meadows, scrub forests, and forest margins. Its thick, glabrous stem can reach a height of 35 cm, but it is not uncommon to find flowering stems half that high, especially in exposed habitats. Each bears up to four pubescent elliptic to nearly ovate leaves, but more commonly just three are present. While single stemmed plants are frequent, in more favorable environments they can form large clumps with 10 or more growing points.

 

Cypripedium tibeticum plant

Cypripedium tibeticum is often rather short in stature, but as you can see their flowers can be large and showy.

Generalizing about the flower is quite a bit more tricky since variation in form and color is extreme. The flower’s natural spread can range from a mere 3 cm to as much as 12 cm depending on the form. More consistent features include a highly corrugated lip surface that is richly flushed with maroon brown to purple pigment, boldly striated sepals and petals, conspicuous hairs on the petals towards their point of attachment, and a mostly glabrous ovary. Flowers are typically born one per stem, however rarely they can be double flowered. Beyond that, it is difficult to talk about similar floral characteristics. Even the often mentioned white ring around the lip orifice is hardly a consistent trait. The various forms I’ve seen or heard about and their characteristics are detailed below.

This is one of the more widespread and common Cypripedium species in western China, indeed extending beyond that country’s borders into adjacent areas of northern India (Sikkim) and Bhutan. Within China it has been found from southwestern Xizang (Tibet), northern Yunnan, much of northern and western Sichuan, southern Gansu, and perhaps even parts of Guizhou (according to eFloras.org). Considering its native range is in such close proximity to Arunachal Pradesh (India) and extreme northern Myanmar, there is likely habitat in those areas as well. It is with satisfaction that I can say this species is not in immediate danger in its native range, despite being continuously subjected to collecting pressure from plant diggers.

This is a plant of high mountains, having been reported from 2,300-4,200 meters elevation. It can be found on grassy to scrubby slopes and meadows (often occupied by yaks), rocky thin woods, forest margins, on travertine formations, perched on scree slopes, and growing out of cliff faces. It is not found in dense woodlands, but rather is a denizen of open environments. In northern Sichuan I have had the great fortune of seeing it growing in all the above situations from ~3,000-3,500 meters elevation, often accompanied by C. flavum, C. calcicola, and C. bardolphianum, and more rarely C. guttatum, C. shanxiense, and C. farreri. It can form sizable colonies, with many dozens of flowering plants in view, or simply grow here and there in small groups.

 

Cypripedium tibeticum seed pod

The seed pod of Cypripedium tibeticum is essentially glabrous and often suffused with purple color. I am happy to report such pods were commonly seen in the wild.

As a side note, all of Sichuan’s Cypripediums favor travertine limestone areas. Travertine is limestone produced by the precipitation of carbonate minerals out of mineral springs, in particular hot springs. Western China is a seismically active region overlaid in many places with limestone rock. Where fissures carrying geothermally heated water to the surface come in contact with limestone, travertine formations can form around flowing hot spring areas.

In Huanglong valley, there is a 3.5 km long travertine formation with multiple pools, and interconnecting streams and waterfalls. The limestone keeps the valley from being densely forested due to the high pH, so much of the area is lightly wooded or has short, scrubby vegetation – a perfect area for Cyps and a host of other terrestrial orchids to grow, notably species of Amitostigma, Galearis, Ponerorchis, Oreorchis, and Phaius delavayi. The shear number of orchids in such sites is shocking, as is the rare beauty of the travertine formations and their deep aquamarine pools.

My experience with this plant in the field is as varied as it is enjoyable. Many people say that C. reginae, or perhaps C. macranthos, is the most beautiful of all Cyps, but after having seen hundreds of C. tibeticum in the wild, this species gets my vote for the most spectacular, at least in Asia. The range of flower types and colors alone make it an intriguing plant. I cannot explain the shear joy of seeing a flowering colony growing on the edge of a travertine pool, the sound of water falling all around, and bold, gray craggy peaks standing in the distance.

 

What’s even more remarkable is the range of situations I have witnessed this plant growing – in immense meadows full of alpine flowers and dwarf rhododendrons, to plants half buried in falling limestone scree slopes, others perched on impossibly steep limestone cliffs growing out of tufts of grass, on tiny islands of scrubby vegetation in the middle of a travertine water course – the variation was breath-taking. What a joy it was to see them all in their native homes – I wanted to photograph every one of them, or just sit there and stare on for an eternity‚Ķ

 

Cypripedium tibeticum habitat

Cypripedium tibeticum is a plant of open habitats. On the left is a open field of limestone scree inhabited by only small trees and shrubs, a perfect area for many Cyps to grow, including this species. The middle photo is of Huanglong Valley's travertine formations, another good growing area for Cyps. The C. tibeticum on the left is growing on the verge of a large travertine pool, just centimeters from the water. One should not be fooled into thinking that this plant likes wet roots however.

 

 

Here are the forms I’ve seen in the wild, starting with the more common ones, and ending with a few odd-balls. Though these are representative of many forms reported in the wild, remarkably they still do not capture the full range for this species! All of these were taken during a botanical tour in late June, 2013 lead by Dr. Holger Perner and his wife, Wenqing.

 

Cypripedium tibeticum, large flowered form

This form of Cypripedium tibeticum is very common in northern Sichuan, it bears the largest flowers of any type, and is the most lovely in my opinion.

 

The most commonly seen form in Sichuan during the trip was this large flowered plant with a white base color to the flower. The petals and sepals are very broad in this type (especially the dorsal sepal), and the lip tends to be rather round and inflated. In some specimens it is more laterally compressed. This was the only type seen at Huanglong Valley, but grew in mixed colonies with other forms of C. tibeticum at other sites. Some of the best clones remind me of the Japanese form of C. macranthos known in the west as hoteiatsumorianum, with flowers up to 12 cm in natural spread. Virtually all the specimens I saw lacked a white ring around the lip orifice – a trait commonly cited for this species. To my eyes, these are the true queens of all C. tibeticum varieties.

 

 

 

 

Cypripedium tibeticum yellow base color

This form has a yellow base color to the flower such that the purple pigments show up as a dark, maroon brown. This type is often known as v. corrugatum in the horticultural trade.

The next most commonly seen form is a flower that has a yellow base color. Due to the yellow color the anthocyanin is expressed as a dark maroon to nearly chocolate brown rather than the pure purple-pink of the previous type. Many also had the commonly reported light colored ring around the lip orifice. These plants seemed to have smaller flowers in general, perhaps averaging only 7-9 cm in natural spread. At the sites we visited they grew in small groups, but this type is one that is known to form large clumps. In the trade it is often called v. corrugatum, though most authorities do not consider that a valid name. Plants of this form are the original type specimens that are the basis of the species, collected over a hundred years ago in northern Sichuan. At the time this region was considered a part of Tibet, ergo the species’ name.

 

 

Cypripedium tibeticum yellow center

A more uncommon plant was this flower with more clear yellow at the center. These were uncommon in the area we were in, but in parts of Yunnan and Xizang flowers with strongly yellow colored sepals and petals are quite frequent.

 

At one site we found a number of plants with decidedly more yellow showing around the base of all the lower parts where they connect to the ovary, including the lip. The lip in these plants was a bit odd looking as well – perhaps more in line with C. calcicola, often with significant dentation on the lip orifice. In parts of Yunnan and Tibet plants with golden color dominating the sepals and petals are more common, and constitute yet another color form of this species. The plant shown here is representative of what we saw, yet there were others with more inflated lips as well – again, it is hard to generalize.

 

 

Cypripedium tibeticum hybrid?

At one site in Sichuan some plants were intermediate between C. tibeticum and C. calcicola. What are these plants? They raise more questions than they answer.

 

 

 

The same site also boasted some odd “in-between” forms – looking something like the closely related C. calcicola, but having C. tibeticum characteristics as well. Dr. Perner said that such plants make him wonder if C. calcicola is truly a distinct taxon, rather than just another form of the highly varied C. tibeticum.

 

 

 

 

 

 

 

Cypripedium tibeticum narrow petaled

Another odd form was this C. calcicola like plant with very narrow flower segments.

If that weren’t enough, I found this plant with ultra narrow sepals and petals in the same colony of C. tibeticum. Plants that definitely fit within the concept of C. calcicola were present in the area, and that species sometimes has more narrow flower segments compared to C. tibeticum, so it is tempting to say this is a natural hybrid between the two species. This was the only plant that had such narrow flower segments, and I saw of hundreds of C. tibeticum during the tour. It is a mystery plant to me.

 

 

 

Cypripedium tibeticum v. amesianum

A dwarf, self-pollinating form of C. tibeticum was also see on the trip. Holger Perner calls these plants v. amesianum based on plants described by Schlechter in 1919.

Finally, there is a dwarf, self-pollinating form, called v. amesianum by Perner (pers. comm.), first described by Schlechter in 1919 based on plants collected in northern Sichuan by W. H. Wilson near the city of Wenchuan. This is a true miniature plant, standing no more than 20 cm tall and bearing a flower at most 4 cm across. The flower is quite round and the sepals and petals are short and fat. Flower color is a fairly continuous shade of maroon purple with a yellow base color. Close inspection reveals that the pollinia grow directly in contact with the stigmatic surface of the column, thus ensuring self pollination. Remarkably, we managed to see flowering plants at two different sites.

This is such a unique plant that Perner feels it deserves specific rank based on its floral characteristics, self-pollinating nature, and dwarf habit. It is close to C. calcicola as well. Eccarius, in his book Die Orchideengattung Cypripedium (2009), has put these plants under the name C. tibeticum ssp. ludlowii which is synonymous with C. ludlowii, yet the herbarium specimens bear no resemblance to this dwarf plant according to Perner. It is such a cool little plant that I’ll dedicate an article to it in the near future.

 

These are the plants I saw in the wild in northern Sichuan. No true alba forms have been located so far, but in Yunnan flavinistic forms have been seen that lack any purple pigment – the flowers are a pure yellow-green color. Pure white flowered forms of v. amesianum were discovered in northwestern Sichuan some years ago, but the colony was completely lost to plant collectors. That is another story which will be told in another article.

Synonymous names with this species include: C. compactum, C. corrugatum, C. corrugatum v. obesum, C. lanuginosum, C. macranthum v. corrugatum, and C. macranthum v. tibeticum. In addition, another proposed variety of tibeticum, v. froschii (Eccarius, 2009), is considered synonymous with a large, pale flowered form of C. tibeticum native to Yunnan. First described by Perner in 1999 as C. froschii, he now considers it an ecotype of C. tibeticum rather than distinct. Other authors have proposed it is the natural hybrid between C. tibeticum and C. yunnanense, but there is no hard evidence that is the case. As mentioned above, C. tibeticum ssp. ludlowii proposed by Eccarius (2009) is synonymous with C. ludlowii, as yet an accepted, if not, mysterious taxon of southeastern Xizang (Tibet) based on a single collection of four flowering plants. In the horticultural trade other names have been given to various forms including varieties giganteum, pallidus, and “mystery tibeticum” – none of which have any validity within the scientific community.

 

Cypripedium tibeticum double flower

This rare double flowered plant was seen growing on a high limestone cliff in a travertine valley.

 

In the wild one confirmed natural hybrid, C. x wenqingiae, has been described (Perner, 1998) based on material from Wenchuan County, in northern Sichuan. This lovely plant is the result of this species hybridizing with the extremely rare C. farreri in just a few localities. Overall it has the appearance of C. tibeticum, but with much lighter flower color, and sometimes more yellow color in the sepals and petals. A potential hybrid swarm between C. tibeticum and C. himalaicum based on one location in southeastern Xizang has also been recorded by Ludlow, et. al., but no official description was ever published.

Given that C. tibeticum grows sympatric with a number of other members of Section Cypripedium, notably C. calcicola, C. yunnanense, C. franchetii, C. cordigerum, and C. shanxiense in various parts of its range, it is possible other natural hybrids have yet to be detected. While C. henryi and C. fasciolatum occupy a similar native range as this species, they are effectively isolated from it due to differences in habitat choice, so it is unlikely that any natural hybrids will be found with these species. An interesting side note is that punitive hybrids have been found between C. franchetii and C. fasciolatum in eastern Sichuan (and possibly Guizhou), two species that are closely allied with C. tibeticum and C. farreri, respectively. It is unlikely that cross section hybrids will be found in nature, despite the close proximity of plants in flower in the wild, particularly C. flavum, C. guttatum, and C. bardolphianum.

 

Cypripedium tibeticum pair

This wonderful pair of flowers show that some forms have laterally compressed lips - a thing of beauty to my eyes.

 

Growing this plant is difficult in many areas, yet if certain rules are followed, it seems amenable to cultivation. Importantly, it requires a long winter rest, and preferably one that is unbroken by warm spells. In its native range plants receive continuous winter conditions from October thru April. The other key element is winter rains – again, in their native haunts there virtually is no significant precipitation in the winter and the ground is frozen solid, hence plants do not tolerate winter wetness well. Also, these are plants of high mountains and plateaus that remain cool throughout the growing season, but with a high day/night differential in temperature. Daily highs might reach 25 C, while the nights could go down to 10 degrees or less. To wit, it would be wise to keep them cold and “dry” in winter, and cool and moist in summer.

Having said all that, this species has been grown successfully in the eastern USA reliably to USDA cold hardiness zone 6. This region is known for heat spells in summer, warm periods in winter, lots of winter precipitation, and yet some have managed to grow this plant. The main trick is to plant them in deep, sharply draining beds, and to keep winter rains and snow off them. A foundation along a north facing wall with no tree cover sounds ideal – thus keeping the plants in the cold shade during warm cycles and keeping winter rain and snow off them as well. If an exposed location is selected, pains will have to be taken to cover the growing area – plastic sheeting seems a good bet. Apparently if these efforts are made, the plant seems to deal with high temperature periods in summer if kept well watered.

To see this plant in the wilds of Sichuan, check out this video:

 

 

A mostly inorganic substrate is suggested – any porous material such as baked clays, perlite, and pumice should form the base of the compost. Additions of non-acidic sand, dolomite, and modest amounts of organic matter are OK as well, as long as you don’t go overboard. In nature the plants grow near a variety of conifer trees, so working pine, larch, or spruce needles into the top layers of the compost should be fine as long as the pH doesn’t drop below 6.5 or so. These plants do not like acidic conditions. Fertilizing can be done throughout the growing season, and is recommended for good growth. Plants can withstand a lot of summer moisture as long as the drainage is perfect – however, they will not tolerate wet conditions around their roots at all.

While they do grow in near full sun conditions in nature sometimes, much of the summer in this region is dominated by monsoonal rains and nearly continuous cloud cover. Interestingly, the sun is quite strong in their native lands, hence this species is well adapted to handling high solar radiation. To keep things safer, I’d grow them in very bright shade with perhaps some sun in the morning hours before 10 AM. In climates where summer heat spells are common, sun should probably be avoided altogether.

This is not a boreal plant, however it is found in cold temperate conditions with long winters. It has been grown successfully outdoors in the USA in Maryland (USDA zone 6b) as well as Victoria, B.C., Canada (USDA zone 8b). It probably is grown optimally in cool summer areas in zones 4-5.

 

Cypripedium tibeticum Huanglong

Coming up on an impressive colony of Cypripedium tibeticum like this in the wild is an experience not soon forgotten. These are located in Huanglong Valley in northern Sichuan.

 

Luckily, artificially produced plants are becoming more available on the market. Hengduan Mountains Biotechnology, Ltd. has offered flowering size seedlings the last few years, and I saw many hundreds of them at their nursery in Huanglong. In America, Bill Steele often offers seedlings for sale, and his son-in-law sells blooming sized seedlings from his nearby operation, Itasca Ladyslipper Farm, in northern Minnesota.

As yet plants offered in other parts of the world (including Chinese suppliers) are often wild collected, though certainly European sources have offered seed grown plants – Phytesia and Raschun come to mind. Word is that Camiel de Jong has teamed up with Anthura in Holland and produced literally thousands of Cyps, so look out for his plants as well – from the pictures I’ve seen, it is an amazing operation that may end up putting smaller competitors out of business. Check out the Garden Orchid site for information about buying their plants.

This wonderful plant is worthy of any Cypripedium garden, yet I hope it also continues to thrive in its native mountains for years to come as well. The entire Tibetan Plateau region is undergoing extreme climate change in recent years, so there is reason to be concerned. And yet, hope remains since this species is found over a huge, largely intact alpine region. My fingers are crossed.

 

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