In Biology, what is the Difference between a Stem Group and a Crown Group?

Rhizome group-Sect. Rhiziridium G. Don, Monogr. All. 55. 1827.

Rhizome group

(Allium family Allium)

Allium aciphyllum ^[2]

At least in the Paleolithic era, humans knew some plants when they collected plant roots and fruit seeds for food. Ancient civilizations such as Greece, Egypt, Babylon, China, and India all recorded plant knowledge. For example, China's "Book of Songs" already pays attention to "know more about birds and beasts and plants".
The Greek student Aristotle of Aristotle was regarded as the founder of botany. The book "History of Plants" or "Plant Investigation" written by him in 300 BC classifies plants on the basis of philosophical principles, depicting their parts, habits and uses. Rome's old Pliny wrote all the botanical knowledge at that time in the 37-volume Book of Natural History, which preceded the dark medieval "Encyclopedia School", but there were many errors.
Many books about plants have appeared successively. For example, in the 1st century AD, the Greek doctor Dioscorides wrote a citation of 600 kinds of plants and their medical uses in his work "On Medicine", which became the basis for describing medicinal plants in the future. The most valuable books of the 15th to 16th centuries of the Materia Medica are German Bronfels, Mattioli of Italy, and Turner of England. This period coincided with the completion of "Compendium of Materia Medica" by Li Shizhen after the middle of the Ming Dynasty in China. In short, until the 17th century, botany was almost entirely limited to descriptions (including woodcuts) and qualitative medicinal plants.
In the early seventeenth century, natural science entered the stage of "experimental science" from "mechanical philosophy". Botany has also moved from description to more purpose. Collected data in a planned and systematic manner, observed the phenomenon, so that experiments were conducted under controlled conditions, and theories and theories were proposed and tested. During this period, the development of physics and chemistry and the application of new tools such as microscopes also played a large role.
The basic principle of modern plant classification was established by British biologist Lei at the end of the 17th century. He divided flowering plants into monocotyledonous and dicotyledonous, and further divided into many plant families that are still in use today. Ray insisted that all the characteristics of plants must be used to judge their relatives, not only a single part of the characteristics. This is exactly the difference between natural classification and artificial classification.
In 1753, Swedish botanist Lin Nai published the "Plant ethnography" and established a double name system. He used reproductive traits (flowers) as an important classification basis. The 24 classes he established were mainly based on the number of stamens of flowers; each class was divided into categories by the number of styles. The simplicity of this system makes it easy to accept and facilitates the collection and investigation of plants, but it is detrimental to botany because of its vague nature classification. For example, according to the Linnaeus system, the lily and barberry are in the same eye, while the sage and the same mint are separated.
Lin Nai's contribution is also to classify about 6000 species into each genus (the same arrangement is used today), carefully describe, and collate the names and descriptions of the species he knows and previous botanists, and then use the two-word nomenclature name. This method was immediately accepted by other botanists. Only from 1753 was it easy and possible to trace a plant from one scholar to another. Since then, researches on plant anatomy, plant physiology, and plant embryology have been developed in parallel with the development of taxonomy.

Paleontology

The science of studying plants in the geological period, including the morphological anatomy, system classification, ecology, time and space distribution of ancient plants, and the history of the origin, development and evolution of various types of plants, ancient flora, the vegetation of endemic times and their Succession, etc. Plant morphology and anatomy, plant taxonomy, plant geography, geobotany, and plant ecology are often linked in research. In application, it often involves geological (especially stratigraphic), paleogeography, and paleoclimatological problems, which is helpful for finding minerals and studying the distribution, division, and comparison of mineral strata containing coal and petroleum.
From 1822 to 1837, A. Bronnard established the classification of plants of the geological period for the first time in his book "History of Fossil Plants". Extensive types were compared with modern plants to establish ancient plants. The basis of learning. The 1840s-90s was the period when paleontology began to flourish. Many people collected a large number of fossils, described ancient plants, and studied the external morphology and internal structure of many extinct plants. , Such as Kodak, Bennetta and so on, and surveyed the fossils in various regions. H. Wesham was the first to study the structure of silicified plants.
By the beginning of the 20th century, A. Natorst's pioneering exploration of the stratum corneum had played a huge role in the study of ancient gymnosperms. Previously, H. Potoni proposed the existence of "Cycadofilices". It was not until 1905 that FW Oliver and DH Scott discovered the relationship between seeds and stems and leaves. "(Pteridospermae), found the missing link between the true fern and gymnosperms. AC Seward and his students did a lot of work in the first half of the 20th century, describing many ancient plants and studying the internal structure. Other paleontologists have investigated the flora of North America, Europe, and the Arctic, laying the foundation for ancient flora research. In 1913 R. Kingston and WH Lan published a study of fossil plants in Rhynie chert, Scotland, and established Psilophytales, indicating that this is the oldest group of vascular plants. Later, new eyes were discovered, such as Caytoniales. Since the 1950s, new orders and subclasses such as Pentoxylales and Progymnospermae have been continuously discovered, and the missing links in some plants have been found to play a significant role in plant systematics.
In recent decades, a lot of data on fossil plants have been accumulated in the history of ancient plant development and paleontology. At the same time, according to paleosporin data, great progress has been made in the changes of paleovegetation and the succession of paleoflora. In application, the establishment of paleosporins has played a huge role in stratigraphy. Since the 1970s, the exploration of microfossils in Precambrian strata and the application of transmission electron microscopy (TEM) and scanning electron microscopy (SEM) have confirmed that bacteria and cyanobacteria existed two or three billion years ago. The scope of paleontology is getting wider and wider.

(1) Celosia:

Morphological characteristics: Amaranthaceae, Amaranthaceae, stems erect and stout, leaves ovate-lanceolate to lanceolate, entire. Ovoid fruit, seeds black shiny,

Garden application: Tall stem species can be used in flower borders, embellish the outer edges of trees, cut flowers and dried flowers. Dwarf seed used for planting flower beds or pots

(2) Beauty Coke:

Morphological characteristics: Canna of the Cannaaceae family, with thick rhizomes and a pseudostem composed of leaf sheaths. There is often a layer of waxy white powder on the pseudostems and leaves. The leaves are large, round to oval-lanceolate, and entire. The leaf color is pink green, bright green or bronze, and there are red and green mosaic or yellow-green mosaic flowers and leaf varieties. . Petals erect, stamens petalized, large and beautiful.

Garden application: It is widely used as potted plants, which can be used as flower beds, flower bands or bushes to be planted on lawns, lake shores, or by the pool. In addition, you can choose different varieties to configure as special gardens, and the flowering season is extremely spectacular.

(3) Palm:

Morphological characteristics: Palmaceae palm, stems cylindrical, unbranched, with fiber network or leaf sheath. The leaves are clustered at the tip of the stem, palmately lobed below the middle, the lobes are stiff and straight but the apex often droops; the petiole has fine teeth on both sides. Flowers small, parthenomorphic; panicles, bright yellow.

Garden application: brown skin is used for making brown ropes, jackets, brushes, etc .; flowers, fruits, and seeds can be used as medicine. It is a good tree species combined with urban and rural greening and garden production.

(4) Camphor tree:

Morphological features: Cinnamomum camphora, ovate oval, thin leathery, three main veins from base, veins with glands, gray-green on the back, glabrous. Fruit spherical, purple-black when ripe.

Garden application: widely used as shade trees, sidewalk trees, shelter forests and scenic forests. At the same time, camphor tree is a tree species with extremely high economic value.

(5) Saponin:

Morphological characteristics: The genus Acacia belongs to the genus Acacia, with trunks or large branches with branched spines, once pinnate compound leaves, ovate and evenly rounded, apex obtuse, and margins having finely blunt teeth. The pods are straight and flat and teach thick.

Garden application: The tree canopy is broad, the tree is beautiful, and the leaves are dense and dense. It is a good shade tree and green trees around it. Trees are hard; pod decoction can be used for washing in place of soap.

(6) Golden Silk Plum:

Morphological characteristics: Hypericum family Hypericum, branchlets arched with two edges, purple. The leaves are small, ovate-oblong. Cymes, golden color, flowering in spring and summer. Calyx ovate, calyx persistent.

Garden application: garden planting or potted ornamental.

(7) Elm:

Morphological characteristics: Ulmus genus, bark longitudinally split, rough; branchlets gray and slender, often arranged in two rows of fishbone-like, leaves ovate, oblong, leaf edges mostly single serrated, slightly asymmetric base.

Garden application: anti-toxic gas can adapt to the urban environment, it should be used as street trees, shade trees, shelter forests and green trees around it. Old stumps can be used for bonsai.

(8) Ginkgo:

Morphological characteristics: Ginkgo biloba belongs to the genus Ginkgo, and the trunk is straight with long and short branches. The leaves are fan-shaped, and the veins are bifurcated. Androgyny, the male plant is tall and erect, the leaves are thick and deeply split, and the leaves are late; the female branches are open or slightly drooping, and the leaves are thin and shallow. Both the male and female flowers are on short branches, the male flowers are drooping, and several flowers are arranged into catkins; the female flowers take up clusters. Seeds are long-stemmed, elliptic to nearly spherical, yellow seed coat, fleshy and foul.

Garden application: Ginkgo trees are magnificent, with large crowns and thick shades, golden autumn leaves and few pests and diseases. They are famous garden shade trees, sidewalk trees, and landscape trees.

(9) Cedar:

Morphological characteristics: Pinaceae, genus of evergreen coniferous trees. The crown of the book is tower-shaped, the main stem stands upright, and the book cover is dark gray and cracked into irregular scaly pieces. The side branches are flat, the branchlets are drooping softly, and there are long and short branches. The plants are dioecious, the male garden is columnar, and the female flowers are oval-shaped. Ball country oval or oval.

Garden application: Cedar branches are beautiful garden landscape trees, which can be widely planted in squares, parks, green spaces, and buildings.

(10) Mosquito mother:

Morphological characteristics: Hamamelis, often cultivated as shrubs; young branches and naked buds. Single field alternates, obovate oblong, slightly toothed at its entire or proximal end, apex obtuse or slightly rounded, lateral veins not prominent on the surface, slightly raised on the back, leathery and shiny, glabrous. Flowers small and without petals, but the red stamens are very conspicuous; axillary short racemes, stellate pubescent.

Garden application: often planted for urban greening and ornamental trees, with hard trees and tannins in the bark.

(11) Luo Hansong:

Morphological characteristics: Lohan pine family Lohan pine genus, broad crown ovate. The bark is gray-brown to dark gray, with shallow longitudinal cracks, flaky shedding, dense branches and leaves, leaf-like lanceolate, spiral alternates, the middle ribs on both sides are obviously raised, the surface is dense green, and the back is yellow-green. Male flowers spike-shaped, female flowers solitary.

Garden application: Luo Hansong is resistant to pruning and can be used as hedges and green walls. Short-leaf Lohan pine ligated with bonsai, rigid and flexible, can be called a good product.

(12) with smile:

Morphological characteristics: Magnoliaceae Michelia, evergreen shrub or small tree, tightly branched, canopy orb. Buds, petioles, pedicels and branchlets are densely rusty brown fluff. Single leaves alternate, leathery, obovate oval, dark green and shiny surface. Flowers are solitary with leaf axils, fragrant, perianth fleshy, pale yellow with purple halo on the edges, flowers are not fully released, and they fall off when fully opened.

Garden application: suitable for cluster planting in parks, hospitals, schools, etc., and can also be planted on the edge of lawns or under sparse forests to form multi-layer mixed communities. Two clusters are aligned at the entrance of the building, and one or two are scattered in front of the window. Fragrant and elegant.

(13) Chinese rose:

Morphological characteristics: Rosaceae, Rosaceae, is an evergreen or semi-long green shrub, often with hook-shaped prickles. Pinnate leaves, clustered flowers, slightly fragrant, single petals, pink or nearly white. Rosehip oval.

Garden application: potted plants can be used for indoor viewing, can be planted in flower beds, flower borders, lawn corners, etc., or can be arranged into a rose garden.

(14) Indus:

Morphological characteristics: Sycamore, Sycamore, book cover green, smooth, single leaves alternate, heart-shaped at base, entire lobes, unisexual flowers, no petals, five sepals, yellowish green; terminal panicles. Capsules crack into 5-scaphoid membranous carpels long before maturity; seeds are as large as peas, born on the fissures of carpels.

Garden application: Suitable for lawn, courtyard, solitary or bush planting, it is an excellent shade tree and sidewalk tree.

(15) Tong Tang:

Morphological characteristics: Rosaceae, Begonia, branchlets are green, smooth and ribbed. Single leaves alternate, ovate or ovate-elliptic, margin densely toothed. Flowers single-petaled yellow, solitary branched. Achenes dark brown.

Garden application: It can be used as a hedge in a garden, or it can be planted on lawns, roadsides, forest margins, beside rockery, which can produce good landscaping effects.

(16) Cherry blossoms:

Morphological features: Rosaceae Prunus, mostly deciduous trees, crowns oval-to-spherical, single leaves alternate, glandular sawtooth, solitary branches with umbrella-shaped or umbelliferous racemes, open simultaneously with leaves Or leaves and flowers later, calyx tube campanulate or tube-shaped, fruit red or black.

Garden application: It is an important flower-viewing tree species. It can be planted in large areas to create a "sea of flowers" landscape, or it can be dotted with green fields to form brocade groups, or it can be planted alone to form the "red in the greenery" painting.

(170 Ziye Li:

Morphological characteristics: Rosa genus Prunus, all parts of the plant body are dark purple, leaves ovate to obovate. Flowers solitary. Leaf axils, single petals, water red.

Garden application: It is an important leaf-seeking tree species in the garden. The full growth period is full of purple leaves, especially in spring and autumn.

(18) Plum blossoms:

Morphological characteristics: Rosaceae Prunus, a deciduous tree, often with branch spines, dry brownish purple, many longitudinal mottled lines. Twigs are green or green. Leaf edges are sharply serrated.

Garden application: In gardens, green spaces, gardens, and scenic areas, it can be planted alone, in clusters or in groups.

(19) Peach tree:

Morphological characteristics: Rosaceae, Prunus, deciduous tree, brown branches, smooth. Buds grow in parallel, mostly leaf buds in the middle, flower buds on both sides, and leaves with elliptic skin needles.

Garden application: It can be planted on the roadside or in clusters on hillsides or streams to form a beautiful landscape. Peach blossoms are also suitable for potting, urging flowers, pile landscapes, and cut flowers.

(20) Sweatshirt:

Morphological characteristics: Metasequoia glyptostroboides, large branches with irregular rotation, opposite branches. The leaves are flat, linear, soft, pale green, opposite, and pinnately arranged. The cones are nearly spherical.

Garden application: important greening materials and ornamental trees in lowland and waterside.

(21) Begonia:

Morphological characteristics: Rosaceae Apples, small deciduous trees, steep branches, gray-brown bark. The leaves are oval and the surface is bright green. The flower is red when it is not blooming, and pink when it is opened. Fruit nearly spherical, yellow-green.

Garden applications: beautify gardens, green areas, streets, factories, mines, courtyards and scenic areas.

(22) Heather:

Morphological characteristics: Rosaceae, Phoebe genus, branches gray-brown. Leaves leathery, oblong to obovate-elliptic, sparsely sparsely glandularly serrate, entire near base, terminal of compound inflorescence. Petals white, nearly round. The fruit is spherical, red and thick brownish purple.

Garden application: The crown of heather has a spherical shape and dense foliage, which is a beautiful ornamental tree. Suitable for solitary planting, bush planting or basic planting. ,

(23) Lamei:

Morphological characteristics: The genus Lameaceae belongs to the genus Lame, with an underdeveloped root and neck, and often forms a large "", the branchlets are nearly quadrangular, the old branches are nearly round, gray-brown, have obvious skin cells, the leaves are opposite, and the oval shape is oval to Oval-lanceolate, entire. Flower buds are solitary in the axillary leaves of that year, and are covered with multiple layers of grayish brown scales.

Garden application: It is often planted on both sides of the entrance of the hall, behind the window and the house, and on the slopes of mountains and autumn.

(24) Bauhinia:

Morphological characteristics: Cercis genus Bauhinia, with smooth, gray branches and cup-shaped or irregular spheres. The leaves are alternate, heart-shaped or nearly round, entire, purplish red, and the pods are flat. They can stay in the village to the following spring.

Garden application: Suitable for planting on the lawns, curbs, etc. of various gardens and green spaces, and can also be composed of evergreen trees or mountains and stones.

(25) Acacia:

Morphological characteristics: Mimosa, Acacia, with an umbrella-shaped canopy, thick branches and sparse branches. Two even-pinnate compound leaves, alternate, linear to oblong. The head is in the form of an umbellate, most of the stamens are slender, and the pink pods are banded.

Garden application: It is most suitable to be planted in the hillsides, streams, lakes and lakes. Urban trunk roads are planted as street trees, and the red flowers and green leaves are full of dark streets.

(26) Hackberry:

Morphological characteristics: Pueraria spp. Has ovate or oval oval leaves, asymmetric base, shallow obtuse teeth above the middle, shiny surface, raised dorsal veins, and sparse hairs.

Plant growth environment is divided into two parts: plant growth environment foundation and plant growth environment regulation. The basic part of the plant growth environment mainly introduces plant growth, plant production, environmental conditions and plant growth; the plant growth environment regulation section mainly introduces the soil environment, light environment, water environment, temperature environment, nutrition environment, climate environment, and biology of plant growth Environment, etc.

(A) species distribution area

A few species of plants are distributed throughout the world and are called world species. In fact, they are mostly halophytes and freshwater aquatic plants, and they are located only locally suitable habitats, and the total area they occupy is not large. The former includes Salicorniaherbacea and Suaedamaritima on saline soil, while the latter includes Phragmites communis, Typha, 15 species of Lemna, and Ceratophyllumdemersum. , Potamogeton and other two (but some are not found in individual continents).

There are many weeds spread around the world due to humans and animals, such as Ptantago major, Solanum nigrum, Chenopodium album, Urticadioica, Taraxacumofficinale, etc. Migration to the tropics, the tropical purslane (Portulaca oleracea), mule (Echinochloa crusg-alli), and salamander (Amaranthns angustifolia), etc., have expanded to temperate zones. The latter is limited by the low temperature in winter, and the number of migrating species is less than the former.

Regarding the total number of species in the world, it is estimated that the distribution area accounts for less than 100 species (or about 30 species) of half of the land, and less than 200 species account for a quarter of the land.

Except for the above-mentioned small number of world species, the distribution of various plants is limited to a certain area, which is called endemic species in the area. This area can be large or small. It can be said to be an endemic species in a certain continent or a natural area, or an endemic species in a mountain or island. Therefore, endemic species are relative concepts, usually divided into continental endemic, provincial endemic, local endemic, and local endemic (Dansereau, 1957).

Taking the species of gymnosperms endemic to East Asia as an example, Pinus sylvestris is endemic to Northeast Asia, Platycladus orientalis is endemic to North China (extended to North Korea), Chinese fir is endemic to the middle and lower reaches of the Yangtze River, and Pseudolarixamabilis is distributed in the hills of the south of the Yangtze River and Cathaya argyra -phylla), Metasequoia and Taiwan fir (Cunninghamiakonishii) are all confined to a very small extent.

(2) Distribution areas of genera and families

Genus is a union of closely related species. The distribution area of each genus is the sum of the distribution areas of the various species included. The genus contains only one type of monotypic genus, which accounts for about 1/3 of the total number of flowering plant genus 25,000. Its distribution area is obviously the same as that of species, but the meaning is different.

Species that are very close to each other within the same genus, either have non-overlapping distribution areas, or have partial overlaps but their internal structures are different from each other (ie, each adaptively has a different habitat). Normally, species cannot cross normally. If the two species are not only similar, but the distribution areas or specific habitats are exactly the same, it is often considered that these are not two independent species, but only different varieties or variants within the same species.

The distribution area of the family is the summary of the distribution areas of the family. The formation of various families and genera has a long history, and the ecological characteristics between species are often significantly different, so the distribution types are diverse and the reasons are complicated.

1. The distribution area structure of families and genera-distribution center

If there are several kinds of concentration phenomenon in the distribution area of multiple genera, the number of species isolines can be drawn accordingly. The area with the most abundant species is called the distribution center or diversity center of the genus. But there may be more than two distribution centers. The distribution structure of the family is similar to that of the genus but more complex.

2. Discontinuous distribution

Most of the families and genera that are continuously distributed have a small distribution range and are not rich in species. Species discontinuities are most common, and there are no long-distance discontinuities. 1) There are 132 genera in the northern temperate zone, including 62 genera such as Acer, Quercus, Alnus, Rosa, etc., which are intermittently distributed in East Asia-Eastern North America. Liriodendron, Gymnocladus, Saururus, Nelumbo, Sassafras, Me-nispermum, Illicium, Purple Tree Genus (Nyssa) and other 155 genera (there are 17 genera and two types each), East Asia-Western North America intermittent Tsuga, Chamaecyparis, Torreya and so on. 2) There are 466 genera of tropical discontinuities, including 231 genera of pan-tropics. 3) There are 9 genera in the southern temperate zone. 4) The 67 genera of north-south temperate discontinuities are different from the first three types of east-west discontinuities. They cross the equator along the mountain to the other hemisphere, such as Gentiana, Empetrum, Salix, Primula and so on. 5) Other discontinuities are 54 genera. Among the 544 families of angiosperms, there are more than 100 discontinuous distributions, and most of them are discontinuous over long distances.

3. Distribution range

According to statistics, there are 12,500 genera of flowering plants, with an average of 18 species per genera. Some genera are not only found on all continents, but also in tropical and temperate regions. They are genus of the world, such as Senecio, Carex, Euphorbia, Solanum, etc. Some aquatic and biophyte plants with narrow ecological ranges, as well as many crops and weeds that have been spread due to human reasons, are also distributed worldwide. In addition, there are 130 genera in the world that are only missing from a certain continent, and they account for 1% of the total. Endemic genera account for 80% of the total number of flowering plants (a total of 10,000 genera).

The distribution range of other genera is at an intermediate level. Generally distributed in tropical regions of the world, called pan-tropical distribution, about 250 genera, such as Bauhimia, Dalbergia, Dioscorea, Hibiscus, Vitex (Vitex) and so on.

About 165 genera are distributed in temperate zones. For example, Acer, Juglans, Alder, Artemisia, Rosa, Vaccinium, Berberis. Discontinuous types of northern temperate zones such as Quercus belong to this range.

The distribution areas of some genera are limited to one continent. For example, 370 genera are distributed only in Asia, 350 genera in the Americas, 110 genera in Africa, and 60 genera in Australia. It is not uncommon to have more narrowly distributed genera. Generally, they are few species or monotypes, such as the metasequoia and silver cedar mentioned above.

Among the 544 families of angiosperms, there are 67 families in the world, including Poaceae, Cyperaceae, Asteraceae, Dianthus, Leguminosae, Labiatae, Liliaceae, and Oviaceae. But each family (or family) has different distribution centers.

Sub-widely distributed families are: pan-tropical distribution, such as sugar apple, palm family, plantain family, etc .; southern hemisphere distribution, such as mountain dragon eye family, broom family (Restionaceae), etc .; northern hemisphere distribution, such as plane family, witch hazel family, Birch family, maple family, tamarisk family and so on. These families have the characteristics of long-distance discontinuous distribution.

The family with a small distribution range can also be divided into different types. For example, there are 72 endemic families in the Americas (of which 47 are in tropical America), 52 endemic families in Asia (of which 22 are in East Asia), and 48 endemic families in Africa (of which 25 are tropical Africa). ), Oceania has 36 unique (of which 19 in Australia), and 9 Mediterranean endemic families. In general, endemic families are rare in small areas.

There are 301 families, 2980 genera, and 24,550 species of seed plants in China (up to 27,150 species of ferns). The types of their distribution areas are very complex. According to the research by Wu Zhengzhang and Wang Hesheng (1983), they can be classified into the following main types.

There are 47 families distributed in the world in China. Each family has many species and rich ecological types, so it has wide adaptability. Many are younger types. There are 108 genus in the world in China, accounting for 3.7% of the national genus. Most of them are distributed in the southwest mountain area, northwest arid area, freshwater and swamp area. These types of world distributions rarely reflect the characteristics of the local flora, and they are often deducted when performing statistical analysis of the flora.

1. Tropical or tropical species

About half of the families in China, namely 168 families, belong to the tropical distribution type, including 1467 genera and more than 8,300 species (accounting for more than 1/3 of the species). The northern boundary of their distribution can infiltrate into various climatic zones, but the tropical center is the main distribution center. For example, there are about 20 genera and 370 species in the family Camphoraceae in China, which are widely distributed in the south of the Huaihe River in the Qinling Mountains. Yunnan has a maximum of about 170 genera and 170 species in 18 genera, and there are more than 20 species in various provinces in the south of the country, such as Lindera obtusiloba. , Mu Jiangzi (Litsea pungens) can reach Jinnan, Shandong or Liaodong. Many of the tropical families belong to ancient types, such as camphor, myristicaceae, borneolaceae, pentaaceae, etc., and taxonomically isolated monophytic and monogenetic families, such as cycads, ramets, Redwood family and so on. These indicate that the flora of China has a long history and has been well preserved during a long geological period. It mainly includes the following types of ingredients:

1) Pan-tropical distribution of about 372 genera in China, some of which are found in the subtropical zone in addition to the distribution center. Among them, Cryptocarya of the camphor family, Dalbergia of the leguminous family, and Pingpo of the family Indus The genus (Sterculia), the genus Casaria (Casearia), and the genus Gentiania (Terminalia) are the main tropical and subtropical tree species in China. A few species of some genera extend to temperate regions, and most of them are herbaceous types, such as Bothrichl-oa, Imperata, Monocotyledonous Commelina, Dioscorea Genus (Dioscorea), genus (Smilax), dicotyledonous plants (Aristolochia), cowhide (Cynanchum) and so on. A few woody plants such as Zi-zyphus, Celtis, Diospyros, Vitex, Evonymus, etc. extend to northern temperate regions and are tropical relics .

2) About 163 genera are distributed tropically in China. Among them, Myristica, Macaranga, and Alpinia are tropical species. Musa is a subtropical species. , Olive (Canariu-m), Acacia, etc. Only very few species are distributed in temperate zones, such as Melia, Mallotus, As-paragus, and so on. This category is mostly ancient and conservative.

3) Tropical Asia to Tropical Oceania are mostly intermittently distributed between tropical Asia and tropical Australia. There are about 150 genera in our country; including Beackea, Myrtle (Rhodomyrthus), Cinnanmom-um, Dillenia, Livistona, etc. . The Ailanthus and Wikstr-oemia can be distributed to North China. Departments of the Southern Hemisphere Distribution, such as Shanlong Ophthalmology, have also extended to China. The above may also originate from the ancient southern continent.

4) There are 89 genera in tropical Asia to tropical America in China, such as Phoebe, Litsea, Eurea, Meliosma, etc.

5) About 151 genera are distributed from tropical Africa to tropical Asia, of which about 74 genera are restricted to the tropics, such as Bombax and Azima; Myrsine and Lemongrass can be found in the Yangtze River Basin. Cymbopogon, Adina, etc .; a few can reach North China, Inner Mongolia and Northeast, such as Periploca, Arthraxon, Themeda, etc. This phenomenon may be due to the long history of direct contact between Asia and Africa.

6) Tropical Asia (India-Malaysia) has the most abundant distribution species, with a total of 542 genera (19% of the total genera in the country). Among them, the monotypic genus and oligotype genus actually reached 263 genus, accounting for about half of this class of ingredients, indicating that it has ancient or primitive properties. For example, the genus Vatica of the Bornaceae family, Litchi of the Sapindaceae family, Mangifera of the Carminaceae family, and Artocarpns of the Mulaceae family are all important tropical tree species. The subtropics include Manglietia of the Magnoliaceae, Michelia of the Magnolia family, Machilus of the camphor family, Engelhardtia of the walnut family, and Gironniera of the elm family. ), Mosquitoes such as Distylium, and other shrubs and vines such as Camellia, Citrus, and Kadsura. A few are distributed northward to temperate zones, such as Duchesn-ea and Chloranthus.

2. Temperate or predominantly temperate families

There are about 77 families, 1209 genera and 4,600 genera distributed in temperate regions in China, which are much more abundant than in other temperate regions. The most important types of distribution are the following.

1) The north temperate zone has 29 families and 296 genera in our country (accounting for 10.3% of the national genera). Almost all the arboreals in the north temperate region, such as cypress, cypress, pine, fir, spruce, larch, taxus and other naked plants, birch, hornbeam (Carpinus), chestnut, oak, beech, Deciduous trees such as walnut, mulberry, fragrant (Fraxinus), poplar, willow, loquat, maple, and elm (some of which belong to the evergreen species in the south). Shrubs include hazel, honeysuckle, rhododendron, rose, spiraea, Philadelphus, Ela-eagnus, and the like. As for the herbs, they are more diverse, such as Artemisia, Sausurea, Potentilla, Aconitum, Trollius, Pedicularis, Pyrola, Maitake (Maiant-hemum), lily (Lilium), willow (Epilobium), primrose, etc., Eurotia, Oxytropis, Agropyrum, Stipa, etc. Wetlands such as seaweed, Acorus, Ali-sma, etc. This rich and diverse phenomenon not only illustrates the integrity of the northern temperate flora, but also shows that China is the most complete area to conserve this type.

2) The East Asia-East North America distribution has been discussed previously and will not be repeated. There are 117 genera in our country (4% of the total).

3) East Asia distribution (Himalaya to Japan) is another most important type of distribution in China. There are 15 families in this distribution in China, such as Ginkgoaceae, Kunlanaceae, Eucommiaceae, Davidiae, Zhongliaoaceae, Aquaticaceae, and Big Blood Vine, etc., which have ancient origins and are unique to China. Branch. There are 298 genera of this distribution type in China, accounting for 10.4% of the country's total, and the species are rich and diverse. The distribution is not limited to temperate and extends to subtropical and even tropical. The woody genera that are distributed throughout the region are mostly shrubs and small trees, such as Pt-erocarya, Eriobotrya, Dendrobenthamia, Keteleeria, Ce-phalotaxus, Moso bamboo (Phyllostachys), palm (Trachycarpus), kiwi (Actinidia), collar spring wood (Euptelea), etc. The distribution of some genera in this area is southwest (Chinese-Himalayan variants), such as Koel-veuteria, Deutzia, Firmiana, Loropetalum, Taiwania, etc. Ancient ingredients and younger ingredients produced when rising in the Himalayas (such as Farina Sinarundinaria). Other genera are partly northeast (Chinese-Japanese style), such as Paulownia, Phellodendron, Weigela, Platycarya, Cryptomeria, Rehmannia ), Etc. and 6 genera of bamboo (Indica Sasa, Pleioblastus, etc.).

4) The Mediterranean West Asia-Central Asia distribution once occupied most of the ancient Mediterranean Sea. Due to the intense drought since the Tertiary, a unique flora was formed. In China, there are 166 genera (accounting for 5.8% of the country), which mainly belong to Asteraceae, Brassicaceae, Chenopodiaceae, Leguminosae, Boraginaceae, Umbelliferae, Poaceae and so on. The genus Anabasis, shuttle, Shaguai, Reaumuria, Zygophyllum and Nitraria are common dominant plants. However, some species of many genera in this distribution type can be found in Australia, North and South America, and especially in Africa, showing that there have been multiple connections with these regions.

5) The temperate zone of the old continent has 157 genera in China, mainly herbaceous plants, such as Dianthus, Se-rratula, Phlomis, Thymus, Achnatherum, and Hidden Substance. Grass (Cleistoge-nes) and so on.

6) There are 63 genera of temperate Asia in China, such as Caragana, Apricot, Filifolium, etc.

7) Central Asia is mainly distributed in the northwestern region of China, with a total of 112 genera, such as Lagochilus, Sp-haerophysa, Hesperidium, Shadongqing, Shapon, etc.

3. China-specific distribution

China's endemic genera totaled 196 genera, accounting for 6.6% of the national genera, and were grouped into 74 families. Among them, there are as many as 142 monotypes, and more than 50 genera are distributed in one province of Yunnan, and nearly half of them are endemic to Yunnan and concentrated in northwestern Yunnan. In Sichuan and Guizhou, there are about 25-30 endemic species. There are 48 genera with few endemic species, and most of them (about 40 genera) are produced in the southwest, and few in other regions. From the origin point of view, some of our endemic genera are descendants or remnants of ancient Tertiary paleotropic flora, while others are types of progress that occurred after the Tertiary.

Among these ancient endemic genera are Camptotheca, Sinofranchetia, Dav-idia, Eucommia, Cyclocarya, Pteroceltis, and One Leaf Kingdonia, Xanthoceras, etc.

Flora can also be divided into more detailed and endemic types, such as geographical components such as the European Siberian component, the Northeast component, and the North China component.