Temperate paradise

 

The Orchid Review

Li Peng, Tang Siyuan, Dong Li, Kou Yong, Holger Perner and Luo Yibo discuss and illustrate some of the many temperate orchids found in the spectacular landscape of the Huanglong valley in Sichuan, China

Huanglong Nature Reserve in Sichuan, China, is famous for its colourful ponds, tufa banks, snow mountains, dramatic landscapes and pristine forests. Huanglong valley, the main tourist destination of the 700 sq km Huanglong Nature Reserve, contains the largest travertine (light-coloured concretionary limestone) formation of its kind in the world.

The 7km long valley gradually rises from 3,100 to 4,000m and runs from south to north. Only the lower part, containing the tufa ponds, is open to tourists up to an altitude of 3,650m. With the Xuebaoding (5,588m), the highest peak of the Minshan mountain range at its top, and the Fujiang river at its base, Huanglong valley is a relatively isolated area.

From late April to early November every year, snow water from the Xuebaoding massif intersects with geothermal spring water highly charged with calcium hydrogen carbonate and carbonic acid, and keeps the valley bottom open and damp. The tufa is deposited on the valley floor. Here, in the Huanglong valley, sunshine, moisture and nutrition - the essential elements for terrestrial orchids - are plentiful.

A total of 34 species in 20 genera of wild terrestrial orchids can be found in the lower 3.6km of this small valley with its maximum width of about 100m. Moreover, Cypripedium flavum, C. tibeticum, C. bardolphianum, Ponerorchis chusua, Galearis diantha, Phaius delavayi (syn. Calanthe delavayi) and Malaxis monophyllos form big populations with each species represented by thousands of plants in the valley.

Such a phenomenon is a rarity, not only in China, and the Huanglong valley fully deserves its status as a UNESCO World Heritage and MAB Biosphere Reserve.

Orchid studies in Huanglong

In 2002 the administration of Huanglong Nature Reserve and the Botanical Institute of the Academy of Science, Beijing, agreed to conduct an orchid research project in Huanglong focused on pollination and population biology. Due to the outbreak of SARS, the scheduled start of the project in 2003 had to be postponed.

In April 2004 the project began with investigations into the pollination ecology of Cypripedium plectrochilum and C. henryi growing at 2,250m in the Danyun gorge, some 25km east of Huanglong Valley. Studies in the valley itself started in May. The genera Amitostigma, Calypso, Coeloglossum, Corallorrhiza, Cypripedium, Epipactis, Epipogium, Galearis, Goodyera, Listera, Herminium, Malaxis, Neottia, Neottianthe, Oreorchis, Phaius, Perularia, Platanthera, Ponerorchis and Tipularia are all at home here and often species of several genera can be found growing side by side.

The flowering season in Huanglong valley starts in May with Calypso and ends in early September with Amitostigma, with the main peak in the second half of June when most genera are in flower. We were so overcome by their beauty and the oddities of pollination that we experienced during our daily studies.

In September 2004, when temperatures dropped severely, the first snow fell and Neottianthe monophylla started to wither, those of us who came from Beijing had to say goodbye to the orchid paradise. However, we will be back when
the next spring wakes the orchids for another season.

Orchid biodiversity

Since 2001, Dr Holger Perner of the Huanglong administration has tried to gather an overview of the orchid flora of the nature reserve. By 2003 he had recorded 58 orchid species in 31 genera in the reserve, including 28 species in 18 genera in Huanglong valley (Perner, pers. comm.). Based on this study, a detailed investigation within the frame of the research project was carried out in 2003 and 2004. We found 34 orchid species in 20 genera in the Huanglong valley, including two genera new for the locality and six species: Coeloglossum viride (now Dactylorhiza viridis), Amitostigma faberi, Cypripedium guttatum, Epipactis monticola, Galearis and Tipularia species. Only one flowering plant of Coeloglossum viride was found and one clump of Cypripedium guttatum with 10 shoots, three of them in flower in 2004.

Orchid habitats

Two main types of orchid habitat occur in the Huanglong valley. One is found on the valley floor, consisting of open shrub with a sparse herb layer rooting in the shallow humus deposits on tufa, with the highest population densities around tufa pools and along rivulets. In this habitat, 24 orchid species are found.

A few single trees occur here, mainly Picea purpurea, Abies faxoniana and some Juniperus. Dasiphora fruticosa (syn. Potentilla fruticosa), Spiraea myrtilloides, Sorbus hupehensis, Prunus pilosiuscula, Rosa omeiensis, Salix tetrasperma, Berberis polyantha, Rhododendron and Lonicera form the shrub layer. Besides orchids and grasses, Arctostaphylos alpina, Polygonum sphaerostachyum and Deyeuxia scabrescens are the main species in the herb layer, whose proportion of cover is relatively low.

Cypripedium bardolphianum, C. flavum, C. tibeticum, Galearis diantha, Phaius delavayi and Ponerorchis chusua are characteristic orchid species in this habitat, occurring in vast numbers and with a wide distribution in the valley between 3,100 and 3,400m.

The second main habitat lies on the valley flanks and is formed by the relatively dense coniferous mountain forest with its sparse shrub layer, few herbs and a dense moss layer covering the entire ground. At higher altitudes the forest becomes mixed forest with Populus cathayana, Betula utilis, Abies ernestii, A. faxoniana and Picea purpurea making up about 70-80 percent of the whole. The sparse shrub layer includes Rosa, Syringa, Sinarundinaria nitida (syn. Fargesia nitida) and Lonicera. Among the herbs are species of Aster tataricus, Allium prattii, Ligularia and Smilax ferox. Several moss species cover the floor and form mats usually 20-40cm deep. Here, 12 orchid species are distributed including four mycotrophic orchids (dependent on soil fungi for nutrients). Goodyera and Tipularia are quite numerous.

Flower chronology

Calypso bulbosa is perhaps the earliest flowering orchid in the valley. Its flowers were in full bloom under the shady coniferous forest when we started the study in the Huanglong valley at the end of May. Cypripedium bardolphianum is the second species to flower in the valley, starting on 24 May in 2004. This unusual miniature orchid with greenish-yellow sepals and petals heavily overlaid with maroon and a golden lip, forms wide colonies with its prostrate rhizome. It grows in open shade around shrubs in shallow humus on tufa, particularly in the low moss cover. The flowers are long-lasting and are already open when the leaves are just partly unfolded.

lipeng@ibcas.ac.cn or Luoyb@ibcas.ac.cn
Tang Siyuan, Dong Li, Kou Yong and Holger Perner work for Huanglong administration, Huanglong valley Seercuozhai, Songpan county, Sichuan 623300, China. E-mail: holger_perner@hotmail.com

Acknowledgements

The authors would like to thank Mr Kou Yahui, Mr Ji Ge, Mrs Wenqing Perner, Mr Yang Baolin, Mr An Dejun, Mrs Tang Shu and Mr Shi Lei of Huanglong administration for their assistance during our study in the Huanglong valley. Financial support is gratefully acknowledged for Luo Yibo from State Forestry Administration, P R China.