Geographical characteristics of plants in China

The geographical location, area, geological historical evolution and climate change in geological period of China are the basic factors that form the characteristics of China flora. There are many kinds of plants in China, with ancient origins and rich vegetation types.

Characteristics and origin of flora

General characteristics

China is rich in plant species. There are about 353 families, 3 184 genera and 27 1 50,000 species of vascular plants, accounting for 56.9%, 24.5% and 1 1.4% of the families, genera and species in the world respectively (table1). In terms of the number of species, it ranks third in the world, second only to Malaysia (about 45,000 species) and Brazil (about 40,000 species) with rich flora in the world.

Judging from the size of plant families and genera, that is, the number of species contained, it is known that there are more than 10,000 species of seed plants in the world and more than 1,000 species in China. Another 50 families in China contain 100 ~ 1000 species, such as Rosaceae, Labiatae and Ericaceae. * * There are more than 19700 species, accounting for more than 80% of the national seed plants, which constitute the basic backbone of China flora.

China plants with ancient origins have ancient origins, containing a large number of ancient or primitive families and genera, and have preserved many remaining plants, such as the ferns and gymnosperms with ancient origins mentioned above. Among gymnosperms, Cycadaceae, Ginkgo, Ephedraceae and Malvaceae are ancient and isolated, each with only one genus. Among them, there is only one kind of Ginkgo biloba, which is generally limited to cultivation, but it is semi-wild in Tianmu Mountain in Zhejiang and northeast Yunnan.

Pine and cypress began to appear in the late Carboniferous and flourished in the Mesozoic, almost all over the world. They began to decline in Tertiary and began to distribute in Quaternary.

Narrower. Although many species have become extinct, there are still many surviving species under favorable conditions in China. Among the 7 existing families, except Taxodiaceae, the others are all in China. White bean fir, silver pine, Metasequoia glyptostroboides and Metasequoia glyptostroboides are all unique relict plant in China, scattered or relict plant are distributed in subtropical and tropical areas in south-central China.

Angiosperms appeared in Jurassic, Triassic, or earlier, flourished in Cretaceous, and gradually developed into the dominant plants in the world in Tertiary. Among the 544 known angiosperms in the world, there are 29 1 family in China, including a large number of ancient or primitive families and genera, such as Magnoliaceae and Camellia. In addition, single species and few species are about 1 135 genera, accounting for about 38% of the total genera in China. Among more than 90 endemic genera in China in/kloc-0, monotypic genera and few species genera account for more than 95%. Most of them are ancient or primitive in origin, which can also reflect the ancient flora of China.

The geographical composition is complex. The geographical elements of China flora are very complicated, and their distribution is staggered and mixed. According to the comparative analysis of 2980 genera of seed plants in China, they can be divided into 15 distribution types and 3 1 variety. Tropical elements 1460 genera (2 ~ 7 categories), accounting for 5 1. 1% of the total genera in China (excluding the world distribution genera, the same below); There are more than 930 genera of temperate elements (8 ~ 1 1, 14), accounting for 32.5%. PaleoMediterranean elements (12, 13) and China endemic elements account for 9.7% and 6.8% respectively. There are many tropical and subtropical elements in the distribution genera of East Asia-North America and East Asia. It can be seen that the flora of China has obvious tropical origin. botanical geography of china

Each component has its main distribution area or distribution center, but it also permeates and mixes with each other. For example, among the 326 typical pantropical genera in China, only 60 genera are confined to the tropics, while 150 genera are distributed in the subtropics, and more than 1 10 genera are distributed in the temperate zone, that is, reaching the northern boundary of its distribution area. As for temperate families and genera, they are widely distributed in China, but they are often mainly produced in subtropical areas from Jiangnan to southwest. Palaeomediterranean elements are mainly produced in arid areas of northwest China, but also distributed in north China or southwest China, such as Tamarix chinensis and some genera and species of Dipsaceae. This distribution trend shows the origin of China flora and its tropical origin.

There are about 200 genera of endemic plants in China, belonging to 72 families. Among them, Compositae, Gesneriaceae, Umbelliferae, Orchidaceae and Labiatae belong to more than 5 families 10 genus, but most of them belong to tropical-subtropical (29) and temperate (22) distribution families. Ginkgo biloba, Calophyllaceae, Davidiaceae and DuDu.

Araliaceae is four endemic families.

Among these genera, more than 95% are single species or few species, except 5-6 genera such as Salix mandshurica, Radix Aucklandiae and Flos Chrysanthemi Indici, and most of them are ancient or primitive types, such as the white bean cedar mentioned above, but also Araliaceae, Aristolochia acuminata, Chimonanthus praecox of Chimonanthaceae, Corylus heterophylla of Corydalis, and Carnation. The four endemic families are also a single species of ancient families. They are mainly distributed in the subtropical and tropical areas south of Qinling-Shandong, especially in the southwest to Central China-East China.

The origin of flora

To sum up, it can be considered that the flora of China comes from the southern and northern ancient lands and the ancient Mediterranean region, all of which are of tropical origin. Modern botanists and paleobotanists have demonstrated the origin of various tropical distribution types in Chinese mainland. As for the tropical origin of temperate flora, there is no consistent understanding so far.

The origin of endemic components in China is quite complicated, including endemic genera and endemic families. Ginkgoaceae, Eucommiaceae, Davidiaceae and Hysteraceae are all single species, and the latter two may be similar to Ulmaceae, Actinidiaceae and Sapindaceae respectively, including two similar species, which are very interesting trace molecules. In addition, in many primitive or older families, such as Magnoliaceae, Lauraceae, Akebiaceae, Chimonanthaceae, Camelliaceae, Actinidiaceae, Hamamelidaceae, Oleaceae, Sapindaceae, Moraceae, Ulmaceae, Aceraceae, Ranunculaceae and Saururaceae, there are endemic genera in China. They are mainly distributed in the mountainous areas from southwest to southeast of China at 20 ~ 40 north latitude, just like the tertiary residual plants of conifers, such as white bean fir, Metasequoia glyptostroboides, and silver fir. Therefore, they undoubtedly originated in the southern part of Palaearctic Continent, and formed and differentiated before Tertiary. In addition, there are a few new types in this region and Tibet, such as Compositae and some genera of Gesneriaceae.

Types and geographical distribution of vegetation

China includes almost all the major vegetation types in the world except the polar tundra, and there are alpine vegetation on the plateau. The natural vegetation in China includes 29 vegetation types, 52 subtypes and more than 600 main formations. The main types are summarized as follows.

forest

The forests in China are mainly distributed in the southeast, and a few are scattered in the mountainous areas in the northwest, with regular strip distribution from north to south.

Coniferous forests and mixed coniferous and broadleaved forests China coniferous forests are widely distributed in mountainous areas of China, which can be divided into cold temperate coniferous forests, warm temperate coniferous forests and warm temperate coniferous forests.

Coniferous forest in cold temperate zone is zonal vegetation in cold temperate zone. In China, it is only found in the northern Daxing 'anling Mountains (400 ~ 1400 meters above sea level) and the northwestern Altai Mountains in Xinjiang (1300 ~ 2 100 meters above sea level), which is the southward extension of the Siberian Tai Jialin. In addition, the subalpine or alpine zone of each mountain is an important part of the vertical zone of mountain vegetation. There are about 50 species of constructive trees in cold temperate coniferous forests in China, mainly including fir, spruce, larch and Sabina vulgaris. The species composition and structure of the community are relatively simple. The well-developed fir forest and spruce forest stand neatly, with a height of 20 ~ 30 ~ 50m and a canopy density of 0.6 ~ 0.9. The undergrowth shrubs and vegetation layers are underdeveloped, but the ground cover moss layer is extremely developed, with a thickness of 5 ~ 15 cm and a coverage of 70 ~ 90%. In the particularly humid subalpine areas in southwest China, there are often a large number of pineapples attached to the forest, forming a special "fog forest" landscape.

Temperate or warm coniferous forests are distributed in temperate and subtropical low hills and subtropical Zhongshan-subalpine belt. Mainly all kinds of pine forests, from northeast to southwest, the main tree species are Korean pine, Pinus tabulaeformis, Pinus densiflora, Pinus armandii, Taiwan Province pine, Pinus massoniana and Pinus yunnanensis. The tropical low hills in southern Yunnan, Guangxi and Guangdong were replaced by tropical coniferous forests of Pinus Simao or Pinus hainanensis. There are many other hemlock, Metasequoia glyptostroboides, Chinese fir, cypress and arborvitae. This kind of forest is secondary forest or artificial forest after zonal vegetation destruction, with different forest forms, generally high 10 ~ 25m and canopy density of 0.3 ~ 0.4 or 0.5 ~ 0.7. However, the species composition is richer than that of coniferous forest, with multi-layer structure. Warm coniferous forests often have many tropical-subtropical elements, and many herbs, ferns and lianas generally grow.

There are typical coniferous and broad-leaved mixed forests in the temperate mountainous areas in the east of Northeast China. The representative tree species are mainly Korean pine, fir and many deciduous broad-leaved tree species, such as Tilia amurensis, Betula platyphylla and Fraxinus mandshurica. There are still some tertiary residual plants in the modern forests in this area, which have the characteristics of subtropical forests.

Deciduous broad-leaved forest is widely distributed in temperate zone, warm temperate plain mountain, subtropical to tropical Zhongshan-subalpine zone and limestone mountain. Typical deciduous broad-leaved forest is a zonal vegetation in humid and semi-humid areas of warm temperate zone in North China, which can extend westward to the upper reaches of Bailong River in southern Gansu. The main tree species are deciduous oak, with Quercus liaotungensis and Quercus mongolica in the north and Quercus acutissima, Quercus variabilis, Quercus variabilis and Quercus mongolica in the south. Most of them are pure forests or mixed species such as maple and linden. The forests are neat and the seasons change obviously. Generally, it is10 ~15m high, and the canopy density is 0.5 ~ 0.7 (0.8). Shrubs and herbs under the forest are well developed, but generally there is no moss layer. Common shrubs are Lespedeza, Spiraea, Honeysuckle, Viburnum, Corylus heterophylla, Cotinus coggygria and so on. Herbs are mainly various subtropical herbs such as Carex, Potentilla, Artemisia, such as Swertia, bothriochloa ischaemum, yellow-backed grass, etc.

In addition, Populus euphratica forest or Elaeagnus angustifolia forest is widely distributed in the northwest desert bank, which is a unique forest type in the desert bank of Central Asia. Below the forest, there are mainly various salt-tolerant shrubs and herbs, such as many kinds of tamarisk, bell thorn, many kinds of licorice and camel thorn. Other kinds of birch and willow mainly form secondary forests or riparian forests, which are distributed all over the country.

Evergreen broad-leaved forest Evergreen broad-leaved forest is a subtropical zonal vegetation with various vegetation types, represented by typical evergreen broad-leaved forest, distributed in low mountains, hills or mountains below 1000 meters (west) in the humid area of central subtropical zone. The constructive plants are mainly many evergreen tree species of FAGACEAE, Lauraceae, Camelliaceae and Magnoliaceae, such as Castanopsis fargesii, Cyclobalanopsis glauca, Lithocarpus, Machilus thunbergii, Schima superba, Manglietia, Michelia and so on. , which is dominant in different regions.

In the northern part of the middle subtropical zone, these evergreen genera and species form an evergreen deciduous broad-leaved mixed forest with some deciduous oak species, Cyclobalanopsis glauca, Liquidambar formosana, Golden Apple, Acer truncatum and Betula platyphylla. In the south of the middle subtropical zone, it is mainly related to Castanopsis kawakamii, Machilus, Syringa (Myrtaceae), Huang Tong (Euphorbiaceae), Du Ying (Elaeagnus angustifolia), Hedysarum (Juglandaceae), Eupatorium odoratum, Eupatorium odoratum and Eupatorium odoratum. Tropical genera and species such as Meliaceae and Saxifragaceae constitute monsoon evergreen broad-leaved forest, which has various characteristics of tropical forest and becomes a transitional type of south subtropical forest. Mediterranean hardwood evergreen broad-leaved forest is often developed in dry-hot valleys and subalpine sunny slopes at the western end of subtropics. Community-building plants are mainly hardwood oaks such as Quercus ferruginea, Quercus conic and Quercus grey, which are generally 2-6 meters high and become short forests or shrubs. Looking up the mountain, this kind of forest is made up of alpine oak trees. The development of bamboo forest is also a remarkable feature of subtropical forest vegetation in China.

All kinds of subtropical forests generally grow rapidly with high density, with a height of 15 ~ 20 ~ 30m and a canopy density of 0.6 ~ 0.9. The tree layer often has 2 ~ 3 sublayers, which are rich in species composition and often have some ancient or residual elements.

Monsoon forest and rain forests are distributed in tropical areas from Taiwan Province, Guangdong and Guangxi to Yunnan and southeastern Tibet, and are part of similar vegetation in tropical Asia. But it is different from the typical monsoon forest and rainforest in tropical Asia. Tropical monsoon forest in China is generally distributed in tropical hilly platforms, leeward or dry-hot valley basins and limestone mountains below 500 ~ 1200m (west). The structure and species composition of this kind of community are very complicated, and there are no obvious constructive species. Dominant plants mainly include various banyan trees, green tangerine peel of Dipterocarpaceae, China Slope, Giant Cherry Tree, Melia azedarach (Meliaceae), Tielimu (Garciniaceae), Pseudostellaria heterophylla (Uteraceae), Araliaceae and Castanopsis fargesii (Araliaceae). The community is semi-evergreen or deciduous in dry season.

Rainforests are distributed in tropical windward hilly lowlands or valleys, with wet rainforests. The representative plants are mainly borneol, slope and Borneo trees of Dipterocarpaceae, nutmeg of Taiwan Province Province, Philippine nutmeg of Myristicaceae, and some species of Sterculiaceae and Moraceae. The tropical west is dominated by dried fruits, such as ebony (Juniperaceae), longan (Sapindaceae), turmeric (Moraceae), Cephalotaxus fortunei, etc. The upper trees contain a certain proportion of short-term concentrated defoliation or defoliation, which becomes a transitional type between tropical rain forest and monsoon rain forest. In addition, it should be pointed out that the representative of Dipterocarpaceae is Chinese mainland, and Myristicaceae is only found in Taiwan Province Province.

bushwood

Refers to the plant community dominated by mesophytes. Except for alpine shrubs and some shrubs distributed in alpine-subalpine, saline-alkali land and sandy land, the rest are secondary and cannot represent zonal vegetation, but they are widely distributed in the current vegetation in China, with obvious regional and bio-ecological differences. The shrubs in China can be divided into three types: alpine shrubs, deciduous shrubs and evergreen shrubs.

Alpine shrubs are mainly distributed in Tianshan Mountain, Altai Mountain, Qinghai-Tibet Plateau and its adjacent mountains in western China, as well as the mountains in Qinling Mountain (Taibai Mountain) and Taiwan Province Province. Generally, the distribution height reaches 3000 ~ 5000 meters above sea level, and it is often combined with alpine meadow or alpine grassland (southern slope of Tianshan Mountain), and distributed between cold coniferous forest and snow line in mountainous areas, which is an integral part of the vertical belt of alpine vegetation. Community plants are all kinds of cold-resistant evergreen conifers, evergreen broad-leaved trees and deciduous shrubs, forming all kinds of alpine shrubs. The main tree species are Sabina vulgaris, Rhododendron, Arnebia euchroma, Caragana sagitta, Mume, Prunus humilis and so on. Communities are generally low and dense, ranging in height from tens of centimeters to 1 m, with a coverage rate of 70-90%. Rhododendron flowers bloom in May and June. Sabina vulgaris shrubs often crawl, with a coverage of only 30-60%, and the appearance and structure of the community are monotonous.

Deciduous shrubs Deciduous shrubs are widely distributed in hills, mountains, valleys, sand dunes, salinized lowlands and coastal habitats from temperate zone to subtropical zone. Especially in warm temperate forest areas, it occupies a large area. The constructive plants mainly include Rosaceae, Spiraea, Sakura, Cotoneaster, Caragana, Leguminosae, Lespedeza, Caragana, Berberidaceae, Corylus, Corylus, Cotinus, Ziziphus jujuba and so on. In the subtropical arid valley, there are mainly tropical Phyllanthus emblica (Euphorbiaceae), weeping willows (Sapindaceae) and saddle leaves (Sumeriaceae). In salinized lowlands, coasts and sand dunes, it is mainly composed of many kinds of tamarisk and Nitraria tangutorum.

Deciduous shrubs are generally 1 ~ 2 ~ 3 meters high, with a coverage of 30 ~ 80%, which mainly varies with the water and salt conditions of the habitat. Most of them are secondary vegetation after forest destruction. If logging is stopped, they can be restored to forests or develop into relatively stable communities.

Evergreen shrubs Evergreen shrubs are widely and sporadically distributed in tropical and subtropical hilly areas (below 500-600 meters above sea level or 1000 meters) and some valleys and coasts. It is mainly composed of many evergreen broad-leaved shrubs and some budding evergreen broad-leaved trees distributed in tropical and subtropical regions. In the subtropical zone, the social plants are mainly Zelkova schneideriana (Hamamelidaceae) and Vaccinium bracteatum (Ericaceae), and in the tropical zone, they are mainly Myrtaceae, Pinus koraiensis (Myrtaceae) and Cupressus altissima (Euphorbiaceae). In limestone mountainous areas, there are many kinds of plants, such as Viburnum europaeum (Caprifoliaceae), bamboo leaves pepper (Rutaceae), Bauhinia rubescens (Hematoxyliaceae), Adiantum ferruginosum (Myrsinaceae), Aquilaria sinensis (Urticaceae) and Leymus chinensis.

Generally, the height of this shrub is about 1 m, and the height can reach 2 ~ 3 meters, with a coverage rate of 40 ~ 80%. The bedding is not obvious, there are often scattered trees, more or less vines and ferns. Common grasses in the herb layer are tall grasses such as imperata, citronella, wild ancient grass, twisted Huang Mao and awn. Sometimes these herbs are dominant and become shrubs and grasses.

lawn

Chinese grasslands are widely distributed in the western part of Northeast China, Inner Mongolia, the northern part of the Loess Plateau, and even the desert mountainous areas in the northwest and the central part of the Qinghai-Tibet Plateau. They are zonal vegetation in temperate and semi-arid areas, and they are also an integral part of the whole Eurasian grassland. They are the most important pastures in China.

The plant composition and structure of grassland vegetation are relatively simple. The constructive plants are mainly Gramineae plants, such as Stipa, Tall Fescue, Cryptomeria fortunei, Leymus chinensis and some compositae plants, such as Artemisia and Chrysanthemum. From east to west, or from top to bottom, desert mountainous areas develop into different types, such as meadow grassland, typical grassland (true grassland) and desert grassland, which are represented by different species.

Typical grasslands are mainly dry tufted grasses such as Stipa grandis, Stipa krylovii, Stipa grandis and Festuca arundinacea.

Meadow grassland is mainly composed of Stipa baikal, Stipa Kirghizia, two species of Leymus chinensis, bothriochloa ischaemum and other semi-arid grasses and a variety of miscellaneous grasses. These two types of grassland communities have neat appearance and obvious seasonal changes. The grass layer is generally 30 ~ 50 cm high and the coverage is 40 ~ 70%. Herb sublayers are obviously differentiated, most of them can be divided into 3 ~ 4 sublayers, and many kinds of small shrubs and weeds are mixed. However, meadow grassland is denser, with richer species composition and more mesophytes.

The transitional types between desert grassland and desert vegetation are mainly composed of grasses such as Stipa Gobi, Stipa breviflora, Stipa arenaria and Stipa orientalis, and small semi-shrubs such as chrysanthemum and Artemisia annua. The community is sparse, low and monotonous, with a height of 10 ~ 20cm and a coverage of 20 ~ 40%.

Alpine grassland is developed in the subalpine-alpine zone of 2700 meters or more in the western plateau and desert mountainous area. Community plants are mainly cold-tolerant and drought-tolerant grasses, such as Stipa purpurea, Stipa grandiflora, Festuca arundinacea, Carex and several Artemisia plants endemic to plateau. The community is short and monotonous, dotted with some alpine mats and weeds.

desert

Desert vegetation is widely distributed in the western part of China's grassland belt and is an important part of the entire Asian desert. On the southern slope of Tianshan Mountain and the northern slope of Kunlun-Altun Mountain, the desert vegetation rises to the height of 2,600-2,800 meters or 2,900-3,200 meters respectively, and the upper part is directly connected with the alpine grassland. The substrate is barren desert soil, saline soil, bare sand dunes and bedrock.

The species of desert vegetation plants are poor, rare and simple in structure. The constructive plants are all kinds of super-arid semi-trees, shrubs, semi-shrubs and small semi-shrubs, mainly including Chenopodiaceae, Compositae, Tribulus, Leguminosae, Ephedra, Calligonum and so on. In the deserts of Xinjiang and western Tibet, there are quite a few ephemeral plants and plants similar to those in Central Asia, and even the tall Ferula beach formed by one-off Ferula, while in eastern Inner Mongolia, there are many ephemeral plants such as sand mustard.

Semi-arbor desert is mainly composed of obscene and white obscene. The former is the most widely distributed community in Asian desert, widely distributed in various substrates in Junggar, Tarim, Qaidam Basin and even Alashan high plains. Baisuosuo Desert is a typical sandy desert vegetation in western Central Asia. It is only found in deserts such as Gurbantunggut in northern Xinjiang, China, and it does not exceed 90 east longitude to the east. These two types of desert plants are various, forming various communities, generally 2-4 meters high, with coverage15-30%, so they are called "desert forests".

Shrub desert is a representative zonal vegetation in eastern Central Asia, which is widely distributed in sandy Gobi, denuded residual hills and sand dunes in southern Xinjiang, Qaidam Basin and western Hexi Corridor. Community-building plants include ephedra, Cynanchum auriculatum, spiny thorn, naked fruit tree, cotton thorn and many kinds of Calligonum mongolicum.

Semi-shrub and small semi-shrub desert are mainly composed of a variety of halophytes, such as red sand, false equisetum, salsola, beer flowers, Gobi Chenopodium, small canopy and a variety of Artemisia (Artemisia capillaris, Artemisia Kashi, Artemisia capillaris, etc.). ). There are halophytes, halophytes, all kinds of salt claws, Suaeda salsa and other succulent halophytes on saline soil. These two types of desert communities are extremely sparse, with a general coverage of 10 ~ 30% and a height of 10 ~ 30 cm, and the shrub desert can reach 40 ~ 50 cm high. The plant composition is also simpler than desert, especially in southern Xinjiang, which often forms a single dominant species community.

Alpine desert is developed in the inner mountain of Kunlun Mountain and the northwest of Qinghai-Tibet Plateau at an altitude of 4000 ~ 5500 meters, and is composed of various cushion shrubs. The constructive plants are Ceratoides arborescens, Chrysanthemum tibeticum and Artemisia arenaria, which are endemic to the plateau. The flora is only 5 ~ 15 cm high, with a diameter of 10 ~ 40 cm and a coverage of 10 ~ 30%. It is dotted with alpine cushion plants such as Oxytropis alpina, Adenophora adenophora, Hedysarum septemlobata and Pinus tibetica, and the growing season is very beautiful and spectacular. Except for the growing and flowering season, it is generally desolate.

Meadow and herbaceous swamp

It can be divided into meadow vegetation and swamp vegetation.

Meadow vegetation is mainly a plant community composed of perennial herbs. Widely distributed in the temperate mountainous areas in the eastern Qinghai-Tibet Plateau and the lowlands or coasts where the groundwater level is close to the surface. Generally, plants grow densely and have rich species composition, mainly including Gramineae, Achnatherum, Leymus chinensis, Sedum, Artemisia, Sanguisorba of Rosaceae, Potentilla, Artemisia of Compositae, Ranunculaceae, Polygonaceae, Saxifragaceae and Primula. Under different conditions, typical meadows, alpine meadows, salinized meadows and swamp meadows are formed. The total coverage of well-developed communities is more than 70% or even 100%, and the grass height is 40 ~ 50 cm to 1 m, with obvious seasonal changes.

Marsh vegetation is a community of moist plants. Herbaceous marshes are the most common in China, appearing in the low-lying areas of lakes, floodplains and river deltas. Especially in areas with warm and humid climate or cold and humid climate, it is widely distributed. Sanjiang Plain in Northeast China and Zoige in North Sichuan (see Zoige Marsh) are two famous marsh distribution areas in China, mainly various Carex swamps. The representative plants in Sanjiang Plain are Carex lasiocarpa, Carex wulanensis, Carex tatou and Carex driftwood. In Zoige, it is mainly Carex Muli, and in Tibet, it is mainly various Artemisia. Carex bog grass layer is generally 30 ~ 50 cm high, with coverage of 60 ~ 70 (80)%, dense roots, and often forms ridged grass hills, commonly known as "tower head". In other swamps, reeds, hops, cattails and bamboo shoots are often dominant or constructive plants except Carex. This community has a high density and is an important source of herbaceous fiber plants.