There are about 300,000 species of plants known on the earth, and many types remain to be discovered. There may be more species living in the past than today, but now they have disappeared. No matter what plant species exist or have lived, they all have their unique geographical distribution.
Each species (or genus, family) is generally not distributed on the surface of the earth, but only appears in a certain habitat, occupying a limited range of the surface, and its geographical distribution is constantly changing. In different parts of its geographical area, its distribution degree is also different. In addition, in nature, plant species usually combine with other species to form communities, and plant communities also have their own unique distribution patterns. The distribution pattern of plant species and plant communities is the research object of plant geography. The germination of plant geography knowledge is very old. In China, the knowledge of plant distribution was recorded in the Book of Songs before the 6th century BC, and it was mentioned in many places that different plants grew in "mountain" and "Ji" (low wetland). Especially for "tree" (Ulmus pumila) and "Ulmus pumila", which are very similar in nature, it was observed that their habitats were different at that time: one was in the mountains and the other was in the primitive forest.
In the 6th century BC, in the book Flower King Gong Ji, it has been pointed out that there is a boundary between the north and south distribution of plants in China due to the differences in topography and climate. The book Guanzi Yuan Di, written in the 5th century BC, has described the vertical distribution of mountain plants and the difference between shady and sunny slopes. The distribution of plants that change with the terrain is also recorded, and 12 plants that change from water to land are listed in turn. The geographical work Shangshu Gong Yu in the 3rd century BC recorded the vegetation distribution in the horizontal zone. In the Southern Vegetation written by Han Ji in the Eastern Jin Dynasty, it is proposed that Nanling is a boundary of plant distribution in China.
In the west, the ancient Greek scholar Ty olaf Stowe first reported the geographical changes of plants. He marched into India with Alexander the Great from 334 BC to 332 BC, and recorded the changes of vegetation (grassland, desert and tropical forest) observed along the way in two books: Vegetation History and Vegetation Papers. However, modern plant geography was established at the end of 18 and the beginning of 19. At that time, in order to find industrial raw materials and overseas markets, some European countries sent many expeditions with natural scientists to conduct large-scale investigations around the world. These investigations have continuously discovered and recorded new plant species and vegetation phenomena, thus laying a foundation for the establishment and development of phytogeography.
Humboldt of Germany, on the basis of a large number of field visits, especially 1799 ~ 1804' s trip to South America and China, systematized the knowledge of plant geography and laid the foundation for the establishment of plant geography, and was called "the father of plant geography". In his series of works, he put forward the concept of phytogeography for the first time, pointing out the dependence of plant distribution on climate and the similarity between the vertical belt in the upper part of the mountain and the vegetation belt in the northern plain. He also confirmed the existence of vertical belts, and pointed out that vertical belt systems have different structures in mountainous areas with tropical, temperate and cold climates. He analyzed the significance of the earth's history in the modern distribution of plants, and put forward the viewpoint of the existence of the origin center and the outward spread of plant species. In addition, he put forward the concept of plant appearance, thinking that appearance represents the natural geographical characteristics of the place where plants live, and divided 19 plant appearance forms, which became the beginning of the later concept of lifestyle.
Under the influence of Humboldt's thought, his contemporaries and later scholars, such as De Kando, Schouw, Grisey Bach and Simpel, all made important contributions to the development of plant geography. Candolle Augustin Pyrame de's Plant Geography, Grisey Bach's Earth Vegetation and Simper's Plant Geography on the Basis of Physiology have all exerted great influence and have long been the basic sources of vegetation knowledge in the world. In particular, phytogeography, which is based on physiology, summarizes the morphology and habits of plants all over the world in detail, and has been reprinted many times, which still has its significance. Because of the work of these scholars, the traditional direction of "eco-plant geography" has been formed.
During this period, Darwin put forward the theory of origin and evolution of species through natural selection, which had a far-reaching impact on plant geography and provided a correct theoretical basis for explaining the law of biological distribution. In addition, Darwin's theory on the development of the organic world puts forward that the environment is an important driving force in the process of evolution, which is of great significance for studying the relationship between organisms and the environment.
The climate classification put forward by Ke Ben at the beginning of the 20th century, based on vegetation, established the climate parameters that meet the boundaries between the main vegetation types, and was adopted by many natural geography textbooks. /kloc-from the end of 0/9 to the beginning of 20th century, Russian agronomist Kuchayev established the theory of natural zone, which promoted the study of vegetation zonality.
In the 1960s, with the emergence of plate tectonics theory, Wei Gena's continental drift theory in 19 12 attracted wide attention. In 1960s and early 1970s, the theory of plate tectonics and continental drift was widely accepted by biogeographers, which explained the distribution of many plants, innovated the traditional "historical phytogeography" and prompted scholars to reconsider the distribution types of plants.
In the late 1960s, MacArthur and Wilson proposed that the number of biological species on the island represents the balance between the opposite rates of settlement and disappearance, which has nothing to do with their systematic kinship, but with the distance between the island and its provenance (mainland) and the size of the island. MacArthur's island biogeography theory has a wide influence and has become one of the important theoretical foundations for the further development of plant geography.
Since 1970s, there have been many works called Biogeography, all of which have the contents of plant geography. German botanist Walter's "Earth Vegetation" is a three-volume book, which summarizes his own investigations around the world and the work of his contemporaries and predecessors, and surpasses the previous similar works in terms of content richness and accuracy.