Seed plant identification experiments
Plant identification is a means of determining the name of a plant, checking the name of a plant rather than fixing a name. Nomenclature is to name a newly discovered species or to verify the correctness of an established name. Source: Experiments in Botany
Operation method
botanical identification
Principle
The classification of plants is mainly based on the morphological characteristics of each part of the plant. When identifying a plant, the first step is to analyze the plant in a comprehensive and detailed manner, and make a good record of the description in order to facilitate the identification work.
Materials and Instruments
Plant material Move (i) General angiosperm analysis of what to observe 1 Life type: is it a tree, shrub, herb (annual, dicotyledonous or perennial), or vine (woody or herbaceous)? What is the height. 2 Roots: what kind of root system? Are there any metamorphoses (woody plants are usually not memorized)? 3 Stem: What is the shape of the stem? Are nodes and internodes evident? Hollow or solid? Does the plant have latex? Is there a distinction between long and short branches? What is the growth habit? What is the branching pattern? Bark color and cracking? Is there a difference between old and young branches? Is there any metamorphosis? Hairy or not? The shape of the buds and the number of buds in the axils of the leaves. 4 Leaves: What kind of leaf arrangement? Single or compound leaves? Are there stipules? What is the morphology of the leaf blade (or leaflets), leaf tip, leaf base, leaf margin and venation? What is the length and width of the leaf blade (in cm)? Are there heteromorphic leaves and metamorphosis? Are there hairs? Are there any other appendages (e.g. auricles, ligule, etc.)? 5 Inflorescences and flowers: solitary flowers or inflorescences? What type? Are there bracts or other glumes, etc.? Flowers: unisexual or bisexual or polygamous? Monoecious or dioecious? What is the stalk (presence or absence, length, etc.), shape of the receptacle, number of stamens and pistils (number of carpels per pistil) and shape of the shade corolla, free or united? Position of the ovary? Are there any appendages such as hairs? Neat or uneven flowers? 6 Fruit and seeds: Fruit type? What is the color, shape, size and odor? What is the shape, color, size and number of cotyledons of the seeds? Is there endosperm? 7 Others: such as the name of the plant, wild or cultivated, habitat, juvenile morphological characteristics or distribution of the notes. (ii) Methods and procedures for observing the external morphology of plant flowers and their anatomical features. The characteristics of chemistry as the main basis for classification should be studied in more detail. Using a magnifying glass, observe the flower from the flower stalk, through the calyx, corolla stamens and pistils layer by layer, and should record as much detail as possible on the features that can be observed, such as the number of each part, color, size and shape, and the arrangement of the relationship between each other (alternate or opposite), etc., and then further observe the characteristics of anther dehiscence, convoluted and placentation. Then use a razor blade to dissect a flower love and longitudinal dissection of a flower, used to observe the placenta and draw the flower pattern, observe the receptacle, perianth and pistil relationship, you can see the position of the ovary (upper or lower), in order to draw the longitudinal section of the flower. Each part of the diagram should be labeled with a name.1 How to determine the number of pistil carpels and the type of pistil in a flower (1) Observe the shape of the ovary. If there is only one pistil in a flower and the ovary is clearly asymmetrical when cut across it, the pistil may be a monopistil consisting of only one carpel. Such as the ovary of legumes. (2) A compound pistil consisting of several carpels, if the stigma and style are separate, then the number of styles and stigmas can be observed instead of the number of pistil carpels. (3) If the pistil is united by several carpels, and if the ovary, style, and stigma are all united, then the stigma can be observed to be symmetrically divided into two or more lobes, and the number of these lobes will indicate the number of carpels. (4) If the pistil stigma completely without fissures, should be dissected to determine the ovary, that is, through the middle of the ovary cross-section to observe the number of ovary cells, the number of ovary cells can generally replace the number of pistil carpels. If the number of atrial chambers can not be judged (such as cucumber, 3 carpels, atrium 1 chamber), the number of placentas can be observed in a cross-section of the ovary, such as cucumber has 3 placentas, it can be determined that the pistil is composed of 3 carpels. If there is only 1 placenta, this pistil may be composed of only 1 carpel. (5) The pistil type can be determined by the above examination. If there is only one pistil consisting of one carpel in a flower, it is a mono-pistil (such as peach blossom); if there is a pistil consisting of more than two carpels in a flower, it is a compound pistil; if there are more than one pistil in a flower, and each pistil consists of one carpel, it is a free carpel pistil. 2 Placenta type: In observing the type of placenta must be determined by cutting the ovary crosswise and longitudinally and observing the ovules if they are born. If the cut ovary is older, the placenta will be seen more clearly. Careful anatomical observation of the plant to be identified and its description in correct scientific morphological terms is the key to plant identification. (iii) Use of search forms After a comprehensive observation of the plant specimen, the relevant books can be consulted for identification. First of all, it is the application of plant search form, which is an indispensable tool for plant identification and a key to recognize plants. The scope of the search form varies, including the national plant search form, the plant search form of a certain region, the ornamental plant search form and so on. In the use, should be based on different needs to utilize different retrieval table, it is best to identify the origin of the plant to determine the retrieval table used, such as to identify the plant is collected in the Ningxia region, you can use the "Ningxia Botanical Records" and so on. The method of using the search form is: first of all, according to the characteristics of the plant to be identified, find out (or determine) to which taxon the plant belongs? If the plant is identified as belonging to the angiosperm dicotyledonous phyla, the dicotyledonous phyla will be used to identify the family to which the plant belongs by checking the family name from the beginning to the end. After finding out the name of the family, use the table of contents in front of the book to find the location of the genus search form of the family, then check the genus name of the plant according to the method of checking the family search form, and then use the species search form of the genus to find out the species name of the plant. (iv) Use of Other Literature on Plant Classification Botanists have compiled a lot of valuable literature, so after the botanical name has been retrieved through the search form, it is necessary to use the literature, check the specimen and other steps to avoid errors. There are many types of literature available for plant identification, such as botanical records, tree records, illustrations, diagrams, atlases, manuals, and monographs, books, journals, etc. of various genera and species. If the collection place or origin of the identified plants is known, the scope of local literature should be from small to large, until the national literature, or even the world literature, if the origin and collection place is not known, the selection of literature, the regional scope should be from large to small, the first check the national and regional literature, and then use local literature. If there is no suitable literature in a certain region, the literature related to or close to this region can be used. The index after each document should be used for checking the Chinese and Latin names. When checking the Chinese names, attention should be paid to the phenomenon of homonymy, and when checking the Latin names, the latest revised names should be cited. The name of the check should be further compared with the text description, diagrams, photos and so on repeatedly, emphasizing the external morphological description taking into account the anatomical features, in order to achieve the purpose of accurate identification. (1) Morphological basis The systematic classification of plants is based on the principle of evolution. Plants in the long-term evolutionary process, under the influence of natural selection, their external morphology and internal structural features are compatible and unified with their relatives and evolutionary degree, so the morphological features of plants become one of the main criteria for classical classification, especially flowers, fruit features are the primary criteria for classification, because it is genetically relatively stable, less subject to environmental influences, followed by the characteristics of the nutrient organs e.; are The second most important criterion is the nutritional organ characteristics e; it is the criterion that can provide the identification other than the flowering period. However, when identifying plants by their nutritional organs, special attention should be paid to their variability because they are affected by the ecological environment and age. When identifying plants, it is also important to distinguish between primary and secondary traits, and between qualitative and stellar variations. For example, the structure of the flower is a primary trait, but the size, color and even the number of petals do not have the same identifying value as their shape, position, and the way they are arranged in the flower bud. Of the secondary traits, coat type is the key, with coat size a little less so. When checking the descriptions, attention should be paid to the traits that are not affected by the environment and other factors and are valuable, to the permissible range of variation within the species, and to the differences between the center and edge of the distribution of the species. (2) Basis of distribution area It refers to the area occupied by a species, genus, family or other taxonomic unit. The formation of the distribution area is the result of a combination of factors, in which the ecological environment as a condition of natural selection plays an important role, and the great changes in the ecological environment also have the greatest impact on the distribution area, but human factors, such as the introduction of cultivation, etc., on the distribution area is also not to be ignored. Although geographic distribution can only be used as an auxiliary material to check the morphological description, it is also very important. The geographical distribution of a species can suggest the possibility of its occurrence in a certain area, thus greatly reducing the scope of search. (3) The basis of waxy leaf specimens Due to the literature in the morphological description often can not all meet the needs of the identified plants, it is difficult to make a final judgment, often with the help of the wax leaf specimens have been stopped identification to check, which is the most simple and effective method. Checking waxy leaf specimens must be carried out after consulting the literature. The value of the preliminary scientific name can be checked according to find the corresponding or similar specimens for checking. In addition to the overall appearance of the specimen, key features must be carefully compared. For more product details, please visit Aladdin Scientific website.
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