Plant specimens can be divided into the following categories according to the purpose of use
(1) Phylogenetic specimen: The purpose of preparation is to observe and study the life history of a plant, that is, the growth of a plant at each stage from seed germination to growth, development, flowering and fruiting. It is commonly used in biological teaching, introduction, cultivation and scientific research.
(2) Whole specimen: usually used to identify plants, scientific names and Chinese herbal medicines. This specimen is also used for vegetation survey in an area. For example, investigate the plant resources of a school or mountain. The roots, stems, leaves and other vegetative organs of higher plants are one of the bases for identifying plants, but they are often different due to different growth environments. The flowers and fruits have relatively stable heredity, which can best reflect the inherent characteristics of plants, and are an important basis for identifying and identifying plants. When collecting specimens, try to collect specimens with complete roots, stems, leaves, flowers and fruits. Herbs should also be dug up underground. The shape and arrangement of sporangia, rhizome, scales and indumentum are important taxonomic characteristics of ferns, which should be paid attention to when collecting. The whole specimen is often made into wax leaf specimen and primary color immersion specimen.
(3) Anatomical specimen: The purpose of preparation is to observe and study the internal organizational structure of a plant organ. For example, dissect the bulb of onion to observe the structure of base plate, bud, scale leaf, fibrous root, etc. The lateral membrane placentation and seed bearing position of cucumbers were observed by transverse dissection; The peach flower was dissected longitudinally to observe its various parts and morphology. To collect this kind of specimen, you only need to select a healthy and representative organ, instead of collecting the whole branch. Anatomical specimens are usually made into antiseptic impregnated specimens.
(4) Comparison specimen: The comparison specimen is mainly used to compare the similarities and differences of an organ of different plants. For example, to compare the seed morphology of dicotyledons and monocotyledons, it is necessary to collect the mature fruits of rape, soybean, cucumber, tomato, etc., remove the peel, dry the seeds, and also collect the fruits of wheat, rice, and corn for comparison. The comparison specimen can be made into wax leaf specimen or air dried specimen, and the fruit soaked with primary color is better.