Plant Resources of Sichuan

(Department of Biology, Sichuan United University, September 1994)

The climate of Sichuan province can be classified as wet subtropic. As the geological conditions are complicated, many kinds of environmental conditions are existing, thus they house very abundant botanical resources. Some 10,000 species of higher plants are recorded (equalling one third of the national register); they belong to over 1,600 genera in 230 families. Nationwide our province's biodiversity holds the second place after Yunnan in ferns (670 spp.) and angiosperms (8453 spp.), in gymnosperms (88 spp.) it is even the richest province in China. Sichuan's agriculture has a long history, so up to now we have over 1, 500 cultivated species, most of them original, so they are well adapted to our environment and bear a great potential for development.

1. Some General Characteristics of the Sichuanese Flora

1.1. Tropic-subtropic and temperate species dominate

Sichuan lies on the border of subtropics and tropics, its landscape is notably diverse, which has proved beneficial for a rich evolution. According to not yet complete investigations [Wu 1991] using the Engler system, Sichuan bears 9,254 species, 1,621 genera and 232 families of vascular plants (whereof ferns: 708 species, 120 genera, 41 families; gymnosperms: 88 species, 27 genera, 9 families; angiosperms: 8453 species, 1474 genera, 182 families). According to their distribution, the species can be classified as tropical (1.7%), both tropical and subtropical (63.2%), exclusively subtropical (mere 0.9%), temperate (29.2%) and arctic ( 5. 6%) . The distribution of genera is 2.9% for tropical, 55. 9% for tropical-subtropical, 4.5% for exclusively subtropical, 34.5% for temperate and 2.8% for arctic areas. From these figures it is evident that Sichuan's flora is largely characterized by tropical- subtropical plants. Nonetheless, the high mountain areas in Sichuan's west and southwest also provide important centers of diversity for temperate genera such as Rhododendron L., Primula L., Gentiana L. and Saussurea L. Arctic and tropic plants contribute only a minor part to Sichuan's flora.

1.2. Endemic genera are numerous

Sichuan's area is large and its ecological conditions vary from alpine-arctic to subtropical. The recent rising of the Himalayas and the relatively mild glacial periods also were auspicious for the formation of an abundant biodiversity. For example, half a dozen species are considered sufficiently diversified to form single-species families as Cercidiphyllum japonicum var. sinense, Davidia involucrata, Tetracentron sinense, Sargentodoxa cuneata and Eucommia ulmoides - all endemic to the mixed forests in Sichuan's southwest. Furthermore, at low altitude forests or cultivated near temples Gingko biloba can often be found. Single-species genera are even more numerous (29), we list a few endemic to south-west China: Tapiscia Oliv., Dichotomanthes Kurz., Emmenopterys Oliv., Davidia Baill., Fargesia Franch., Spenceria Trimen, Salweenia E.G.Baker, Kingdonia Balf.f. et W.W.Sm., Psilopeganum Hemsl., Atropanthe Pascher, Dickinsia Franch., Dinolimprichtia Wolff, Siphocranion Kudo, Sinojohnstonia Hu, Sinofranchetia Hemsl., Psammosilene W.C.Chen, Vertrilla Franch., Itoa Hemsl., Hosiea Hemsl. et Wils., Cathaya Chun et Kuang, Metasequoia Hu et Cheng, Heterolamium C.Y.Wu. Likewise, oligo-species genera often are relics of very distinct taxa, too - some Sichuanese examples are: Faberia Hemsl., Pterygiella Oliv., Speranskia Baill., Bretschneidera Hemsl., Dipteronia Oliv., Chimonanthus Lindl., Biondia Schltr., Asteropyrum J.R.Drumm et J.Hutch., Dipelta Maxim., Przewalskia Maxim., Notopterygium Boiss., Urophysa Ulbr., Oligobotrya Bak., Ancyclostemon Craib., Isometrum Craib., Dipoma Franch., Hemilophia Franch., Diuranthera Hemsl., Dysosma Woodson, Nannoglottis Maxim., Xanthopappus Winkler., Melliodendron Hand.-Mazz., Sindechites Oliv., Meehania Britton., Hanceola Kudo, Ostryopsis Decne., Rostrinucula Kudo, Bolbostemma Franquet, Gymnotheca Decne., Thyrocarpus Hance, Schnabelia Hand.-Mazz., Tetrapanax K.Koch, Torricellia DC., Solms-Laubachia Muschler, Sinojackia Hu, Discocleidium Pax ex Hoffm., Hemiboea C.B.Clarke, Tremacron Craib., Corallodiscus Batalin, Pararuellia Bremek. and Kinostemon Kudo. These great numbers of indigenous plants indicate Sichuan's flora is both ancient and special: among the angiosperms 464 species (5.48%) are currently considered as true endemics.

1.3. Many relict species prove antiquity

Sichuan's vegetational history is quite long, its western part has been above sea level since paleozoic times [Guan 1990]. As elsewhere, during mesozoic times it bore are cycadophyte-pteridophyte covering. The climate became dryer during the Cretaceous (most forests disappeared), but in the Tertiary became warmer again. Most crucial, East Asia was lucky to pass a milder Quarternary glacial period than comparable areas in Europe or North America, thus many species could survive here. Although during the quartery glacial periods in the west Sichuan high mountain ridges glaciers formed, this has not affected the survival of many ancient species, many of them moving south via the Hengduan Mountains (p.e. fir forests moved down to 1500m in Xichang, or even 1100m in Panzhihua [Liu 1977]), and then radiating again in the Quarternary. Ancient plants found in present Sichuan comprise ferns such as the paleozoic Psilotum, Angiopteris, the mesozoic Osmunda, Dicraepteris, Hieropteris, the jurassic Cyathea and Cibofinum, the cretacreous Plagiogyria and the tertiary Pteris, Lycopodium and Lygodium. Sichuan harbors three very famous "living fossils": Gingko, Cathaya and Metasequoia, other ancient gymnosperms are the prejurassic Cycas, the cretaceous Pinus, Picea, Torreya, Cephalotaxus, as well as Keteleeria, Abies, Tsuga, Cryptomeria, Cunninghamia, Podocarpus and Ephedra for the Tertiary. There are about 50 ancient angiosperm families formed in the Cretaceous as the Trochodendraceae, Cercidiphyllaceae, Moraceae, Celastraceae, Rhamnaceae, Aceraceae, Magnoliaceae, Lauraceae, Ranunculaceae, Fagaceae, Hamamelidaceae, Betulaceae, Juglandaceae, Menispermaceae, Ericaceae et al. as well as 30 tertiary families like the Myricaceae, Simarubaceae, Saururaceae, Alangiaceae, Hippocastanaceae, Nyssaceae, Sabiaceae, Flacourtiaceae, Stachyuraceae, Theaceae, Bretschneideraceae, Styraceae, Verbenaceae, Davidiaceae, Symplocaceae, Bignoniaceae, Polygalaceae, Meliaceae, Eleagnaceae, Calycanthaceae and Eucommiaceae.

1.4. Gymnosperm diversity

With 88 species in 27 genera and 9 families Sichuan is China's richest province in gymnosperms (nationwide we count 232 species, 34 genera, 10 families), so 79.4% of the Chinese genera or 37.9% of China's species are represented. Most abundant are the Pinaceae (43 spp.), followed by the Cupressaceae (17 spp.), Cephalotaxaceae (6 spp.), Taxodiaceae, Podocarpaceae, Ephedraceae (5 spp. each), Gingkoaceae and Cycadaceae (1 sp. each). 14 species (15.9%) are endemic. The other Sichuanese gymnosperms are occuring in neighboring provinces, too, as in Yunnan (46 spp.), Hubei (31 spp.), Gansu and Guizhou (each 30 spp.), Tibet and Shaanxi (each 23 spp.) and Qinghai (only 9 common spp.).

The plant community of Sichuan developed from a paleomediterranean-cretaceous plant community and can now be considered as subtropical. For its rich evolution the rising of the western part of the province was very auspicious: many habitats become disconnected during glacial periods providing many oppurtinities for further diversification. The differences the alpine and subtropic areas can be summarized as follows: In the western mountains, albeit the number of genera being low (mainly Abies, Picea, Pinus, Tsuga, Larix and Sabina), their distribution is wide, but according to geomorphology, mosaic and gradient distributions do often form. Here Picea and Abies are particular dominant, with the exception of Abies fargesii West Sichuan contains all provincial representatives of these two genera, and is being a major center of diversity nationwide. Here you'll find extremely cold-resistant species like Picea likiangensis var. balfouriana and Abies squamata which survive up to 4500m and 4600m respectively. On the other hand Abies ernestii and Picea wilsonii are more adapted to warmer environments at 2200-2800m with a maximum of 3200m. The former although belonging to the genus Abies grows well on dry slopes, whereas Picea wilsonii will grow in damp ravines! Many examples like this demonstrate a high degree of diversification.

On the other hand, in the eastern part of the province, gymnosperms do not coin the whole vegetation, but many tertiary relict plants survived. Interesting examples are Metasequoia glyptostroides, Glyptostrobus pensilis, Cathaya argyrophylla, Fokienia hodginsii, Amentotaxus argentotaenia, Thuja sutchuenensis, Gingko biloba, Pseudotsuga sinensis, Keteleeria davidiana, Cunninghamia lanceolata, Torreya fargesii, Taxus sinensis, Cephalotaxus fortunei etc.

2. Phytogeography of Sichuan

A glance on the map of present distribution of tree societies shows that Sichuan can be divided into three major landforms. In the eastern part lies the subtropic Sichuan basin (including the major cities as Chengdu, Chongqing etc.) surrounded by mostly lower mountains (1500-2000m), such as the Micang and Daba Mountains in the north, the Wu and Qiyao Mountains in the east, the Dalou Mountains in the south, Longmen, Emei, Lower and Upper Liang Mountains in the west. The north-western part of the province, however, is characterized by the adjacent Qinghai-Tibet plateau grasslands (3500-4500m). Between the basin and the grassland a zone of high mountain coniferous forests can be found (3000-4000m).

2.1. The basin (east & central Sichuan) and evergreen broad-leaved woodlands (south-west Sichuan)

This region is situated south-east of the counties Pingwu, Maowen, Baoxing, Kangding, Luding, Jiulong and Muli, it thus comprises nearly the whole province with the only exception of the Gansun and Aba Tibetan autonomous regions. In the Sichuan basin and its surrounding lower mountains the climate is hot in summer, mild in winter, frosts are seldom, rain is plenty (1000-1200mm p.a.) all over the year, it's moist and misty. Average annual temperatures mainly range between 16-19 C. In the Hengduan mountains regions in south-west Sichuan, monsoon periods gradually become more distinct: winters are quite dry, whereas summers are very damp. The typical vegetation comprises subtropical evergreen broad-leaved forests (Fagaceae, Lauraceae, Theaceae, Magnoliaceae, Symplocaceae), subtropical coniferous woods (Pinaceae, Taxodiaceae, Cupressaceae) and bamboo stands. The natural conditions are very good in this area, but as the densely populated basin is mainly used for agriculture, wild plants are confined to wastelands, riversides or village woods. The east is characterized by south-eastern monsoons, the climate is very humid, frosts are seldom, there is no distinguished arid period, which supports humid evergreen broad-leaved forests (Lauraceae, Fagaceae, Theaceae) and subtropical coniferous forest (mainly composed of Pinus massoniana, Cunninghamia lanceolata and Cupressus funebris). The fertile center of the basin is dominanted by a long agricultural history, so dominant trees are Pinus, Abies, Cupressus, many Bambusoidae, Lauraceae, Alnus, Eucalyptus etc. Citrus sinensis and related species are widely cultivated. In these regions, two to three harvests a year a possible, so agricultural crops dominate, but an estimated 1,000 to 1,500 species of medicinal herbs still can be found. Representative families are Moraceae, Ranunculaceae, Crucifera, Leguminosae, Rutaceae, Meliaceae, Combretaceae, Umbelliferae, Scrophulariaceae, Lamiaceae, Campanulaceae, Compositae, Alismataceae, Gramineae, Liliaceae and Zingiberaceae. The vegetation in the surrounding lower mountains (1,500 to 2,000 spp. of medicinal plants) is far more heterogenous, as it is largely influenced by latitude and precipitation gradients. In the south and southwest, temperatures are high, precipation is abundant, in the evergreen broad-leaved forests Schima, Gordonia and many liana shrubs are typical. In the west and northwest of the basin although it is slightly colder than in the south, precipitation is still high, so in these broad-leaved forests Cinnamomum wilsonii dominates, but also liana shrubs, all kind of epiphytic and parasitic plants as well as mosses are common. On the colder slopes of the Northeast Sichuanese Daba Mountains as also in the mountains east of the basin, the forests begin to be dominated by Fagaceae, Theaceae (yet Lauraceae are still quite numerous). Summarizing, plants found in the mountains around the basin are: Auricularia auricula, Tremella fuciformis, Polyporos umbellatus, Lygodium japonicum, Equisetum hiemale, Cibotium barometz, Osmunda japonica, Cyrtomium fortunei, Davallia mariesii, Pyrrosia lingua etc. for the fungi and ferns; Pinus, Taxus, Cupressus, Ephedra as representative gymnosperm genera; common angiosperm families are: Moraceae, Urticaceae, Loranthaceae, Aristolochiaceae, Polygonaceae, Amaranthaceae, Phytolaccaceae, Caryophyllaceae, Ranunculaceae, Lardizabalaceae, Berberidaceae, Menispermaceae, Magnoliaceae, Lauraceae, Papaveraceae, Cruciferae, Saxifragaceae, Eucommiaceae, Rosaceae, Leguminosae, Geraniaceae, Rutaceae, Meliaceae, Euphorbiaceae, Coriaceae, Rhamnaceae, Vitaceae, Theaceae, Araliaceae, Umbelliferae, Cornaceae, Ericaceae, Oleaceae, Gentianaceae, Asclepiadaceae, Convolvulariaceae, Lamiaceae, Solanaceae, Acanthaceae, Plantaginaceae, Rubiaceae, Valerianaceae, Caprifoliaceae, Dipsacaceae, Cucurbitaceae, Campanulaceae, Compositae, Gramineae, Cyperaceae, Araceae, Stemonaceae, Liliaceae, Dioscoreaceae, Iridaceae, Zingiberaceae, Orchidaceae etc.

Of the western Sichuan highlands, the southern part is also influenced by the monsoon climate in the procumbent lower mountains surrounding the basin, drought and rain period are clearly distinguishable. This area is characterized by broad-leaved woods formed by drought-resistant species like Fagaceae etc. or subtropical conferous forests (Pinus yunnanensis, Keteleeria evelyniana, Cupressus duclouxiana). About 2,500 species of medicinal plants are located here, for example Polyporus, many ferns, Ranunculaceae, Lardizabalaceae, Phytolaccaceae, Berberidaceae, Menispermaceae, Magnoliaceae, Rosaceae, Leguminosae, Araliaceae, Umbelliferae, Ericaceae, Gentianaceae, Scrophulariaceae, Dipsacaceae, Campanulaceae, Compositae, Gramineae, Araceae, Stemonaceae, Liliaceae, Dioscoreaceae and Iridaceae. At higher altitudes (1,000 to 2,000m) in the same evergreen forests other species become abundant, for example: Cinnamomum wilsonii, Lindera glauca, Phellodendron chinense, Mahonia gracilipes, Schefflera octophylla, Sch. delavayi, Helwigia japonica, Hedera nepalensis var. sinensis, Akebia trifoliata var. australis, Sinomenium acutum, Cocculus trilobus, Paris polyphylla, Liriope spicata, Cibotium barometz, Cyrtomium fortunei, Pyrrosia petiolosa and Lepisorus thunbergianus.

Where evergreen and deciduous broad-leaved forest mix (2,000 to 2,600m) plant societies change again, notable representatives of this area are: Ilex cornuta, Eucommia ulmoides, Gastrodia elata, Coptis chinensis, Cimicifuga foetida, Asarum sieboldii, Panax bipinnatifidus, Anthriscus sylvestris, Convallaria majalis, Veratrum nigrum, Hemsleya amabilis, Pyrola rotundifolia, Astilbe chinensis, Polygonum runcinatum, Dysosma veitchii, Oxalis griffithii, Actinidia spp., Aralia chinensis, Celastrus orbiculatus etc.

In the south west Sichuan river valleys at low altitudes some wild tropical plants are found: Oroxylum indicum, Calotropis gigantea, Opuntia dillenii, others are cultivated like Andrographis paniculata, Pogostemon cablin and Amomum villosum. In subalpine shrubland Iphigenia indica is common.

2.2. Alpine coniferous forests (western Sichuan)

This region is located west of the counties Pingwu, Maowen, Baoxing, Kangding, Jiulong and Muli and southeast of Dengke, Zhuqing (Dege county), Hexi (Seda county), Nanmuda and Chazhenliangzi (Rangtang county), Huangshengguan (Songpan county) and Ruoergai. It comprises the whole counties of Nanping, Songpan, Heishui, Lixian, Maerkang, Jinchuan, Xiaojin, Danba, Kangding, Daofu, Qianning, Xinlong, Dege, Baiyu, Yajiang, Yilun, Batang, Xiangcheng, Daocheng, Derong, Litang and parts of the counties Ruoergai, Hongyuan, Rangtang, Wenchuan, Maowen, Gansun, Luhuo, Dengke and Muli. This zone borders to the Qinghai-Tibet high plateau, its moutains are steep and, while being rich in geothermic energy, its geomorphology is complex. Its eastern mountain valleys abundant in spruces, firs and pines, form the (somewhat overlogged) major wood resource for Sichuan. In its west, subalpine shrublands and meadows begin to dominate. For some river valleys, an average annual precipitation of ca. 600mm and an annual medium temperature of 12 C might be given, but local climatic conditions are varying very much according to altitude.

The subalpine shrublands and meadows are rich in medicinal herbs, for example Fritillaria cirrhosa, Rheum officinale, Gentiana macrophylla, Astragalus membranaceus, A. folridus, A. chrysopteris, A. tongolensis, Paeonia veitchii, P. suffruticosa, Rosa banksiae, Lamiophlomis totata, Dracocephalum tanguticum, Meconopsis spp., Aconitum spp., Berberis spp., Gentiana spp., Lloydia serotina, L. tibetica, Arisodus luridus, Stellera chamaejasme, Heracleum candicans, Thlaspi arvense and Descurainia sophia. Among major aromatic oil plants are Rhododendron cephalanthum, Rh. fastigiatum, Rh. flavidium and Sabina spp. In alpine rock deserts above 4,500m medicinal herbs are Fritillaria cirrhosa, Saussurea spp., Soroseris spp., Eriophyton wallichii, Lagotis ramalana, L. integra, L. brevituba and Solms-Laubachia pulcherrima.

2.3. High plateau grass- and shrublands (north-western Sichuan)

This region is situated north-west of the line Dengke, Zhuqing (Dege county), Hexi (Seda county), Nanmuda (Rangtang county), Aba, Chazhenliangzi, Huangshengguan (Songpan county) to Ruoergai. It wholly or partially contains the counties Shiju, Aba, Dengke, Dege, Seda, Gansun, Luhuo, Tangrang, Hongyuan, Ruoergai and Songpan and belongs to the Qinghai-Tibet high plateau. From 3,300-4,000m in the east it gradually rises to 3,900-4,500m in the west. The river valleys are broad and not deeply incised and hills are quite flat, so mostly the height difference between river bed and surrounding hilltops does not exceed 400m. This climate is cold (medium temperature ca. -1 C) and dry (precipitation about 650mm), irradiation is intensive. Grasslands (Roegneria nutans, Poa pratensis, Agrostis schneideri, used for grazing yaks and sheep) dominate, intertwined with shrublands and marshlands. At some places, fragmented subalpine coniferous woods occur.

Medicinal plants populating shrub- and grasslands are: Fritillaria cirrhosa, Rheum officinale, Lasiosphaera nipponica, Thamnolia vermicularia, T. subvermicularia, Nardostachys chinensis, Cirsium souliei, Aconitum spp., Saussurea spp., Lagotis spp., Meconopsis spp., Przewalskia tangutica. Other plants are rich in starch, for example: Polygonum viviparum, P. sphaerostachyum and Potentilla anserina. Last, but not least, in the grassland of Shiju county edible fungi (as Tricholoma sordidum) are numerous.

In short, the vertical distribution is quite distinct anywhere in Sichuan: we can distinguish the agricultural region (below 1,200m), a surrounding secondary shrubland area (900 to 1,500m), an evergreen broad-leaved forest belt (1,400 to 2,000m), a zone where evergreen broad-leaved and deciduous forests mix (1,800 to 2,500m), subalpine and alpine conifers (2,500 to 3,200m), alpine shrublands and meadows (3,200 to 4,500m) and alpine rock vegetation (above 4,500m).

3. Plant Resources in Sichuan

We count over four thousand of species of plants used by man, in this respect Sichuan is the richest province in China.

3.1. Pharmaceutical plants

3.1.1. Diversity

The encyclopedical newest "Register of Important Natural Resources"(Sichuan Sheng Zhongyao Ziyuan Pucha Minglu, 1986) lists 4,103 medicinal plants, that is 2,673 species more than the "Sichuanese Flora of Chinese Medicine"(Sichuan Zhongyaozhi) dating from 1960. These 4,100 plants used as medicine count for 75% of the plants used in whole China - Sichuan is the province most extensively using herbal medicine nationwide. Of this great number of plants, about one fourth is already commercialized. Among the medicinal plants, over 200 are export products, most popular are Ligustrum wallichii, Liriope spicata, Aconitum carmichaeli, Coptis chinensis, Paeonia lactiflora, Codonopsis pilulosa, Angelica dahurica, Salvia miltiorrhiza, Chuanminshen violaceum, Fritillaria cirrhosa, Gastrodia elata, Pinellia ternata, Eucommia ulmoides, Magnolia officinalis, Mahonia shenii, Melia toosendan, Croton tiglium, Vladimiria souliei, Dendrobium clavatum var. aurantiacum, Notopterygium forbesii, Nardostachys chinensis, Cyathula officinalis, Dipsacus acer, Dendrobium nobile etc. From 1950 to 1983, 550,000 ha were cultivated with medicinal plants, equalling to 16,100 ha annually. The products were sold for 2.04 billion Yuan (annual average: 60 million Yuan).

Presently, the herbs selling best in Chengdu are p.e. Gentiana scabra, Duchesnea indica, Prunella vulgaris, Centiella asiatica. For the treatment of icteric hepatitis Lysimachia christinae is used, its market also being quite considerable. Many medicinal herbs are being analyzed for valuable ingredients to produce pharmaceuticals: For example, from Hyoscyamus niger six kinds of alkaloids have been isolated which are able to cure several kinds of diseases. Other successes have been achieved with Dioscorea zingiberensis, D. panthaica and D. nipponica, from which a dozen of products have been derived. About 200 plants are being suspected of high pharmaceutical interest presently.

Most medicinal plants have not been thoroughly investigated, but recent exploitations testify that their potential benefit is large. For example, Hippophae rhamnoides and H. thibetana are distributed over all 13 counties in the Aba district, and they are estimated to bear some 3,500 tons of berries annually. When grinded to medicine powder or diluted to drinks, seabuckthorn can control man's body functions: clinical studies show that the flavonoids it contains can support the treatment of coronary diseases. Besides, its kernels can be used top produce precious oil. Many companies in Aba district are exploiting this plant now. Besides producing beer, Humulus female inflorescences are well known to be a potent medicine which can cure digestive problems, cystitis, pulmonary tuberculosis etc., over 70 tons are now produced in Nanping, Maoxian and Mianzhu. Cephalotaxus fortunei protects against cancer, the reserves are 5 tons distributed Nanping and Wenchuan county, not included minor deposits in other counties like Tianquan, Shimian and Lushan. The entire plant of Rhodiola has for long time been used as Chinese medicinal herb, it is assigned to "activate the blood (circulation), calm down the lungs, treat coughing and tranquilize the neural pain", which modern science explains by its glycosides stimulating leukocyte production and thus preventing cancer, too. On the alpine regions of Wenchuan, Xiaojin, Heishui, Maerkang, Ruoergai etc. at least 650 tons of Rhodiola can be found. Other plants with extensive reserves are Astragalus membranaceus, Ephedra spp., Schisandra chinensis, Bupleurum chinense, Rheum officinale, Arisaema consanguineum, Polygonatum sibiricum, Cuscuta chinensis, Scutellaria baicalensis, Polygonum multiflorum, Lamiophlomis rotata, Peucedanum spp., Uncaria rhynchophylla, Campanumoea javanica, Gentiana rhodantha, Liriope spicata, Hedyotis diffusa, Paeonia lactiflora, Berberis sargentiana etc.

Another very interesting potential are the folk medicines of the Tibetan and Yi minorities (about 1,000 plants are in use). For example, the Tibetans use Lagotis integra (Scrophulariaceae, related to the Indian Picrorhiza scrophulariifolia) as a potent antiphlogistic.

3.1.2. Distribution of pharmaceutical plants: some examples

In the Sichuan basin (region I A), below 1,000m many pharmaceutical species are cultivated, for example Paeonia veitchii in the Ju and Zhongjiang counties, Paeonia suffruticosa in the Shijiang and Changchou counties, Coptis chinensis around Shizhu, Aconitum carmichaeli at Jiangyou city, Quisqualis indica in Hechuan county, Agastache rugosus from Nanchuan and Chongqing, Salvia miltiorrhiza from Zhongjiang and Jintang counties, Ligustrum wallichii from the area round Dujiangyan, Liriope spicata is produced in Zexie, Mianyang and Santai, Croton tiglium in the counties of Xuyong and Gong. In the wasteland, on woodsides or near villages common medicinal herbs are Imperata cylindrica, Prunella vulgaris, Polygonum multiflorum, Lygodium japonicum, Lysimachia christinae, Tetrapanax papyferus, Clematis armandii, Kalimeris indica and Ajuga decumbens, whereas in the evergreen broad-leaved forests on the lower and middle hillsides Dicranopteris dichotoma, Lygodium japonicum, Poria coccos, Scutellaria amoena, Sc. hypericifolia, Bupleurum chinense, Saposhnikovia divaricata and Bletilla striata are typical species.

Vertical distribution on the southern slopes of the Daba Mountains (Region I B6): Below 1,300m, the vegetation is dominated by evergreen broad-leaved forests (Cyclobalanopsis glauca, Lithocarpus cleistocarpus, L. polystachyus). Occasionally subtropical conferous woods (Pinus massoniana, P. henryi, Cupressus funebris), bamboo forests (Phyllostachys nigra, Pleioblastus amarus) and deciduous forests (Quercus acutissima, Q. variabilis) occur. Agriculture centers on corn and rice (one or two harvests a year). In this environment, common medicinal plants are Poncirus trifoliata, Schizonepeta tenuifolia, Mentha arvensis, Bupleurum chinense, Carthamus tinctorius, Pinellia ternata, Cyperus rotundus, Pueraria pseudo-hirsuta, Lygodium japonicum, Chaenomeles sinensis, Morus alba, altogether some 400 species are counted. In the heigth range from 1,300m to 2,000m mixed evergreen-decidious forests dominate (mainly: Cyclobalanopsis oxyodon, C. glauca, C. myrsinaefolia, Lithocarpus cleistocarpus, Fagus longipetiolata, Quercus spp., Toxicodendrum vernicifluum, Betula spp.). Some deciduous forests mainly composed of Cyclobalanopsis glauca associate with the conifer Keteleeria fortunei. Agriculture is mainly based on corn and potatoes (one harvest a year). Dominating medicinal herbs are Platycodon grandiflora, Angelica dahurica, Carthamus tinctorius, Coptis chinensis, Eucommia ulmoides, Gardenia jasminoides, Liriope spicata, Ziziphus jujuba, Paeonia lactiflora, P. suffruticosa, Bupleurum chinense, Schizonepeta ternifolia and some other 600 species. At altitudes from 2,000 to 2,800m subalpine coniferous forests dominate (mostly Abies fargesii, other components are secondary Populus spp., Betula spp. and Pinus armandii). At relatively protected sites one harvest per year is possible, but under harsher conditions agriculture soon ceases. Major medicinal plants are Eucommia ulmoides, Magnolia officinalis, Mahonia shenii, Magnolia wilsonii, Codonopsis pilulosa, Dendrobium clavatum, Gastrodis elata, Adenophora stricta, Aconitum carmichaeli, Hemsleya chinensis, Magnolia denudata, Rhododendron spp. and about another 700 species.

Located on the western edge of the Sichuan basin, the vertical plant distribution of Mt. Erlang (I D11) reads like this: In the lower strata below 1,800m evergreen broad-leaved forests dominate (Cyclobalanopis glauca, Castanopsis spp., Cinnamomum spp., Phoebe zhennan). Approaching to the 1,800m line, the border region is inhabited by Lithocarpus cleistocarpus and Cyclobalanopsis oxyodon. Here one can also find subtropical coniferous forests (Cunninghamia lanceolata, Cupressus funebris, Pinus massoniana) or interspersed Phyllostachys pubescens bamboo associations. Agriculture is founded on rice and corn (one or two harvests per annum). Major medicinal herbs are Atractylodes macrocephala, Melia toosendan, Mahonia shenii, Eucommia ulmoides, Akebia quinata, Sargentodoxa cuneata, Lonicera japonica, Epimedium sagittatum, Pytolacca acinosa, Asarum sieboldii, Gastrodes elata, Equisetum hiemalis, Dendrobium nobile, Houttuynia cordata, Lygodium japonicum, Pyrrosia lingua, Poria coccus, Stachyurus himalaicus, Lysimachia christinae, Prunella vulgaris, Sinapsis alpa, Coix lacrima-jobi, Clerodendron cyrtophyllum, Corydalis edulis, Uncaria rhynchophylla, Arundo donax, Cuscuta australis, Senecio scandens, Millettia reticulata and Ganoderma lucidum. At altitides from 1,800 to 2,000 meters, deciduous and evergreen forests confuse. Dominant species are Castanopsis spp., Cyclobalanopsis oxyodon, Davidia involucrata, Fagus longipetiolata, Cercidiphyllum japonicum, Lithocarpus cleistocarpus and Cyclobalanopsis glauca (the latter two species being found in protected rivulet valleys). The only major agricultural product is maize (one harvest a year). Among the medicinal herbs are: Angelica sinensis, Cyathula officinalis, Aucklandia lappa, Magnolia officinalis, Coptis chinensis, Lonicera japonica, Asarum sieboldii, Schizandra sp., Gastrodes elata, Dipsacus asper, Arisaema heterophyllum, Oplopanax elatus, Disporopsis fuscopicta, Caulophyllum robustum, Scrophularia buergeriana, Vellaris solanacea, Polyporus umbellatus, Poria coccos, Akebia trifoliata, Trichosanthes kirilowii, Bergenia purpurascens, Ligusticum sinense. At altitudes from 2,200 to 3,200m alpine conifers are clearly dominant. Its upper part is almost exclusively composed of Abies faxoniana, Picea brachytyla and Tsuga chinensis. In protected areas, Sinoarundinaria nitida may form subalpine bamboo shrublands, or birches, poplars and alders occur at riversides. Agriculture is sparse and only some potatoes are cultivated. Major medicinal plants are Usnea longissima, Paeonia lactiflora, Arisaema heterophyllum, Cimicifuga foetida, Oplopanax elatus, Aralia cordata, Polygonum paleaceum, Acanthopanax gracilistylus, Cassiope selaginoides, Trillium tschoskii, Heracleum hemsleyanum and Aconitum carmichaeli.

The greater Liangshan mountains (I E12) in southwestern Sichuan are jointly influenced by both the south-eastern and south-western monsoons, so the composition and vertical distribution has both features of that in alpine mountains and valleys. Below 2,600m, the vegetation is dominated by broad-leaved forests (Castanopsis delavayi, C. orthocantha, Cyclobalanopsis glaucoides, C. delavayi, Cinnamomum longepaniculatum, Phoebe neurantha, Lithocarpus variolosus, occasionally Cinnamomum wilsonii, Neocinnamomum delavayi, Schima argentea and some Magnoliaceae). In the underwoods, shrublands or alpine meadows there are Poria coccos, Dipsacus japonicus, Pinellia ternata, Arisaema heterophyllum, Scutellaria amoena. Along riversides, Bombax malabaricum, Psidium guajava, Phyllanthus emblica etc. form sparse-tree meadows, sometimes Opuntia dillenii and Zygophyllum xanthoxylum happen to occur in succulent shrublands. The subalpine forest zone ranges from 2,600 to 3,800m, its lower part is dominated by Tsuga dumosa, Ts. chinensis, Acer spp. and Betula spp. The upper coniferous woods are composed of Picea likiangensis, Abies georgei, A. forrestii and A. fabri. In the upper regions, only naked barley and potatoes are used agriculturally, whereas in lower valleys maize and winter wheat are cultivated, too. Some typical medicinal plants are Poria coccos, Paeonia lactiflora, Arisaema heterophyllum, Pinellia ternata, Cimicifuga foetida, Heracleum hemsleyanum, Dipsacus acer, Scutellaria amoena, Saposhnikovia divaricata, Schisandra chinensis, Berberis sargentiana and Mahonia gracilipes. Progressing to altitudes from 3,800 to 4,500m the vegetation will change to alpine shrublands (Rhododendron spp., Quercus semicarpifolia) and meadows (Artemisia spp., Festuca spp.). Here no agriculture is possible, but medicinal herbs can still be found: Notopterygium forbesii, Rheum dalmatium, Astragalus membranaceus, Jurinea souliei, Usnea longissima, Rhododendron spp. In alpine stone deserts from 4,500 to 5,200m Saussurea japonica and Soroseris hookeriana sparsely occur.

In the Hengduan mountain slopes belonging to south-west Sichuan (I E13,14) the distribution can be characterized as following: The upper and middle Minjiang River valley (below 1,000m) is filled with evergreen broad-leaved forests, subtropical coniferous forests (mostly Cunninghamia lanceolata), shrublands (Cotinus coggygria var. pubescens, Sophora viciifolia, Lycium chinense, Berberis spp.) or deciduous oak forests. Rice and maize are produced (one or two harvests per year, depending on altitude). The most important medicinal plants are Paeonia suffruticosa, Berberis spp., Bupleurum chinense, Asarum sieboldii, Lysimachia christinae, Houttuynia cordata, Prunella vulgaris, Akebia quinata, Equisetum hiemalis, Stachyurus sp., Pyrrosia lingua, Plantago asiatica, Smilax glabra, Epimedium brevicornum, Arctium lappa. At altitudes of 1,600 to 2,000m evergreen and decidous broad-leaved forests mix, in dry river valleys there are shrublands dominated by Sophora viciifolia and Quercus spp. deciduous forests. In these areas, mainly maize is produced (one harvest annually). Plants of pharmaceutical interest are: Paeonia suffruticosa, Magnolia officinalis, Schisandra chinensis, Magnolia liliflora, Dipsacus acer, Arisaema consanguineum, Arctium lappa, Asarum sieboldii, Polyporus umbellatus, Angelica sinensis, Codonopsis pilulosa, Cyathula officinalis and Aucklandia lappa. When advancing to heights of 2,000 to 3,800m subalpine conifers dominate (Abies ernestii, A. faxoniana, A. fabri, Picea purpurea, P. asperata, Cyclobalanopsis glauca, at protected sites Tsuga chinensis). Agriculture does not exceed a limit of 3,200m and mainly consists of maize, winter wheat, naked barley, potato, spring rape etc. Medical plants are very plentiful here. The dominating ones are Codonopsis pilulosa, Angelica sinensis, Astragalus ernestii, Rheum dalmatium, Notopterygium franchetii, Jurinea souliei, Usnea longissima, Paeonia veitchii, Arisaema consanguineum, Cimicifuga foetida, Adenophora tetraphylla, Aralia cordata, Aconitum carmichaeli, Dioscorea spp., Berberis thunbergii, Saposhnikovia divaricata, Asarum sieboldii, Polyporus umbellatus, Bupleurum chinese, Paeonia spp., Uncaria rhynchophylla, Rhododendron spp., Rubus spp. Between 3,600 and 4,400m typical vegetation consists of alpine shrublands and meadows. The shrublands are composed of Sibiraea angustata, Caragana spp., Rhododendron spp., Rheum dalmaticum, Astragalus ernestii, Jurinea souliei, Fritillaria cirrhosa, Gentiana macrophylla, Aconitum carmichaeli, Stellaria chamaejasme, Ephedra spp. and Quercus aquifolioides. The meadows are dominated by Gramineae and Kobresia spp., but also rich in Fritillaria cirrhosa, Gentiana macrophylla, Veratrum nigrum, Taraxacum spp., Aconitum brachypodium and Lasiosphaera spp. At altitudes between 4,400 and 4,800m, only alpine rock vegetation is to be found. Distributed in the Yalongjiang river valley shrublands (2,400 to 3,000m), drought-resistant species dominate (p.e. Sophora viciifolia, Opuntia dillenii, Oroxylum indicum, Pogostemon cablin, Amomum villosum etc.). Above 3000m the Yalongjiang river valley vegetation resembles that of Minjiang river.

In the highlands of north-west Sichuan (III) the absolute altitude is high, but relative height differences are minor. The highlands are rising from east (3,300m) to west (4,000m). The vertical vegetional distribution is not very sharply defined. Generally speaking, at sea levels from 3,300 to 4,200m the vegetation is composed of subalpine to alpine shrublands and meadows. Widely distributed medicinal plants are Rheum dalmaticum, Astragalus ernestii, Notopterygium forbesii, Gentiana macrophylla, Vladimiria souliei, Fritillaria cirrhosa, Rhododendron spp., Aconitum carmichaeli, Ephedra spp., Stellaria chamaejasme, Lasiosphaera spp., Taraxacum spp., Hippophae thibetana, Cordyceps chinensis, Dendrobium clavatum var. aurianticum, Nardostachys chinensis, Codonopsis pilulosa, Saussurea involucrata, Sibiraea angustata and Potentilla fruticosa. In the sparse rock vegetations located above (4,200 to 5,000m) Saussurea involucrata, S. japonica, Rhodiola spp., Eriophyton wallichii, Fritillaria delavayi and Lagotis brachystachys are the main representatives. Alas, due to the harsh climate conditions, large-scale exploitation is likely to be a very onerous task.

3.2. Other plants of economic value

Oil plants: Over 300 species of oil plants are recorded for Sichuan, half of them have oil contents above 20%, many of them with excellent fatty acid compositions. The low altitude evergreen broad-leaved forests around the basin consist of many laurels like Cinnamomum glanduliferum, Lindera communis, L. megaphylla, Litsea cubeba as well as tea plants as Camellia oleifera and C. sinensis. At higher altitudes (shrublands or mixed forests) important oil plants are Toxicodendron vernicifluum, Rhus chinensis, Cornus controversa, Juglans cathayensis, Xanthium sibiricum and Coriaria sinica. From the dry south-west Sichuan river valleys the tropical Jatropha curcas and Dodonaea viscosa should be mentioned.

Aromatic oils: Over 200 species. Most laurels rich in aromatic oils need are damp and warm climate, so like Cinnamomum longepaniculatum, Lindera megaphylla, L. communis they are concentrated in low altitude evergreen broad-leaved forests joining the basin; however some heliophilic representatives like Litsea pungens, L. cubeba and L. populifolia will grow in shrublands or sparse forests on badly eroded mountain slopes. Furthermore, the dry south-western river valleys bear Osyris wightiana, Cymbopogon citratus, Ruta graveolens and other tropical aromatic oil plants. In arid river banks below 3,200m some aromatic oil plants can be found, for example Osyris wightiana, Caryopteris terniflora, C. incana, C. divaricata and C. forrestii.

Fruits: Not including already cultivated species, already about 100 species of wild fruit are considered to be apt for production of nutrients.

Starch: Starch-rich Fagaceae are widely distributed: In the mountains around the basin at about 2000m Quercus acutissima, Q. variabilis, Q. aliena, Q. fabri and other oaks often form deciduous forests, sometimes radiating into coniferous woods above. Where the broad-leaved forests are evergreen, Castanopsis eyeri, C. fargesii, C. platyacantha and Lithocarpus polystachyus are more common. Starch-rich plants concentrated in the low altitude (anthropogenous) shrublands are Pteridium revolutum, Pueraria lobata, Pyracantha fortuneana, Smilax spp., Dioscorea spp. and Corylus spp.

Vegetables: Over 50 species of wild plants are used as vegetables.

Fibers: Some 220 species can be used. In the east Sichuan hills, planes and mountains below 1,500m small-stalked bamboo woods (Phyllostachys heteroclada, P. nigra var. henonis) are used for paper production. Here, at higher altitudes Chimonobambusa utilis, Ch. szechuanensis stands are also found. In the west Sichuan subalpine areas Sinoarundinaria chungii and S. nitida grow among evergreen and deciduous woodlands. In poor shrublands surrounding the other basin plants with a high fiber content are Debregeasia edulis, Mucuna sempervirens, Pueraria lobata, P. edulis, Actinidia spp. and various palms. Below 1,300m, Bombax malabaricum grows in the dry river basin of Jinsha River and its affluents.

Tannins: More than 150 species are considered as tannin reserves. Tannin-containing Fagaceae are widely distributed around the basin: they participate in such diverse societies as broad-leaved evergreen low hill forests, all kinds of mixed broad-leaved woods up to deciduous oakwoods. In shrublands, rose plants form a major tannin resource. As for tannins, there are of course huge reserves in tree-barks of west Sichuan subalpine conifers like Pinus densata, Picea asperata, P. likiangensis, P. purpurea, Abies ernestii, A. faxoniana, A. georgei, A. squamata, Larix potaninii and L. potaninii var. macrocarpa. On southern alpine slopes between 2,000 and 4,000m oak forests are numerous, rich both in tannin and starch reserves. Repesentative species are: Quercus aquifolioides, Q. longispica, Q. spathulata, Q. rehderiana, Q. monimotricha. Many fungi like Russula virescens, Auricularia auricula etc. grow here.

Fodder crops: More than 1,000 species, many of them rich in protein, are used. Aquatic plants are used as forage too.

Due to its long agricultural history, Sichuan is also quite rich in varities. For example, the Institute of Agriculture collected 10,000 probes (7,525 of them preserved) of 11 common species: Rice, wheat, corn, sweet potato, potato, broad beans, peas, soy beans, rapeseed, cotton and sugar cane ["Exploitation of Plant and Animal Resources in Sichuan", 1988].

4. Cited Literature

Guan Zhongtian (1990), The forest changes in South-west China during diverse geological periods, in: Li Chengbiao [Ed.], Ecological Study of Sichuan Forest, Sichuan Publishing House of Science & Technology, Chengdu, pp. 187-208.
Li Chengbiao (1990), General geographical divisions of Sichuan forests, in: Li Chengbiao [Ed.], Ecological Study of Sichuan Forest, op.cit., pp. 295-307.
Liu Yandong (1977), Pollen at lower Jiegeda and its meaning for the dynamics of quarternary glacial periods, J. Bot. Sin.
Wu C.Y. (1991), The areal-type of Chinese genera of seed plants, Acta Botanica Yunnanica, Suppl. IV.
Academia Sinica (1960), Pharmaceutical Flora of Sichuan, Sichuan People's Press, Chengdu.
Vegetation of Sichuan (1980), Sichuan People's Press, Chengdu.
Exploitation of Animal and Plant Resources in Sichuan (1988), Sichuan Social Sciences Press, Chengdu.