Basic requirements for collecting plant specimens

(a) the collection method of plant specimens:

1. Time and place of plant specimen collection

The growth and development stages of various plants are long and short, so it is necessary to collect them in different seasons and at different times to get various specimens in different periods. Therefore, it is necessary to decide the time to go out and collect according to the plants to be collected.

The location of the collection is also very important. Because different plants grow in different environments, such as plants on sunny slopes and shady slopes, plants growing in mountainous areas and plains must be different. Therefore, when we collect plant specimens, we must determine the time and place of collection according to the purpose and requirements of collection, so as to collect the required and different types of plant specimens.

2. Problems that should be paid attention to in the collection of seed plant specimens

(1) Complete specimens must be collected. Cut or dig branches or whole plants with flowers and fruits that can represent this plant, and the size should be controlled within the range of 40 cm long and 25 cm wide. Some families, such as Umbelliferae and Cruciferae, are difficult to distinguish without flowers and fruits.

(2) Some families and genera with underground stems (such as bulbs, tubers, rhizomes, etc.) are difficult to identify. ), such as Liliaceae, Amaryllidaceae, Araceae, etc. Do not collect underground stems, so pay special attention to the underground parts of these plants.

(3) Female plants and male plants should be collected separately for identification.

(4) Collection of Woody Plants Generally, woody plants refer to trees, shrubs or woody vines. When collecting, the plants with normal growth and no pests and diseases are selected as the collection objects, and the representative tricks are selected as the specimens. It is best to collect specimens with leaves, flowers or fruits, and if necessary, take some bark. You should use branch scissors to cut the specimen, but you can't fold it by hand, because it is easy to hurt the tree by hand folding, and it is not beautiful to press the picked branches into specimens. However, it must be noted that when collecting deciduous woody plants, it is best to collect them in three periods in order to get a complete specimen. For example:

① winter bud specimen;

② Florescence specimen;

③ Fruiting specimens.

Because some plants bloom first and then grow leaves, such as Yingchun, Chimonanthus praecox and Bauhinia. Then collect flowers first, and then collect leaves and fruits later, and you can get a complete specimen. Generally speaking, a specimen without flowers and fruits can not be used as the basis for species identification, so branches with intact leaves and flowers (or leaves and fruits) must be collected, and biennial branches should be brought to the specimen at the same time, because the branches born in the same year are abnormal and sometimes difficult to identify. In addition, the relationship between dioecious plants, such as poplar and willow, etc. The size of the specimen taken is generally about 42 cm long and 29 cm high. This conforms to the length and width of white paper, and the binding is more beautiful after drying.

(5) Collection of Herbs The collection method of tall herbs is generally the same as that of woody plants. In addition to collecting its leaves, flowers and fruits, it is also necessary to collect its underground parts, such as rhizomes, creeping branches, tubers and roots, and dig as much as possible, which is very helpful to determine whether the plant is annual or perennial. Many herbs are classified according to underground parts, such as Gramineae, bamboo, sedge and other plants. Without underground parts, it is difficult to identify them.

(6) Collection of aquatic plants Many flowering plants live in water, and some kinds of petioles and flower stalks grow with the water depth. Therefore, when collecting these plants, underground stems can be used for those with underground stems, which can show the position of flower stalks and petioles. But when collecting, it must be noted that some aquatic plants are soft and fragile. When it comes to the surface of the water, their branches and leaves paste together and overlap, and often lose their original shape when they are brought back indoors. Therefore, when collecting this kind of plants, it is best to pick them in bundles, wrap them in toilet paper, put them in the collection box, bring them back indoors and put them in pots or barrels immediately. When the branches and leaves of the plant are restored to their original state, put an old newspaper under the water-receiving specimen, gently lift the specimen out of the water, and then immediately put it into hay paper and press it. In the first few days, it is best to change the dry paper 3-4 times a day until the moisture on the surface of the specimen is absorbed.

(7) It is very difficult to collect special plants, such as Palmae or Musaceae, which have large leaves and long petioles. Therefore, only a part of their leaves, flowers, fruits and barks can be collected, but their height, stem diameter, leaf length and width, petiole and leaf sheath length and shape must be recorded. It is best to take photos of them and attach photos.

(8) To collect parasitic plants, it is necessary to collect the parasitic parts of the host at the same time, and record the relationship between the types and forms of parasites and parasites, such as collecting samples such as Taxodium, Taxodium, Cuscuta, etc.

(9) Number of samples collected: Generally, 2-3 samples should be collected and given the same number, and each sample should be labeled with a number. In addition to self-storage, for some difficult types, you can also send a copy with the same number to the research institution. Please help me identify it.

The above collection methods can only be used to make preserved leaf specimens. If the flowers or fruits are soaked with drugs to keep their original shape, they can be used as demonstration materials or experimental materials. Flowers and fruits must be put in a collection box and brought back indoors for soaking.

3. Recording method

When we collect in the wild, we can only collect a part of the whole object. Many plants are very different in color and smell after being squeezed. If the collected specimens are not recorded in detail, the memory will be blurred in the future, so it is impossible to know this plant like the back of your hand, and it will be more difficult to identify it. Therefore, when collecting in the field, recording is extremely important, and collection and recording are closely related. Therefore, before going to the field, you must prepare enough collection records, and you must write them down together with the collection. Only in this way can we form a habit and master the method of off-site recording skillfully. Only by mastering the field records can we ensure the smooth acquisition work. How to start recording? For example, the origin, growth environment, traits, color of leaves, color of flowers, color of fruits, fragrance and milk, and collection date of plants should be recorded. Note that there are often two leaf shapes on the same plant. If only one leaf shape can be collected, it will be helpful for recording. Besides, we can only collect some tall perennial herbs such as reeds. Therefore, we must record their height, the number and color of aboveground and underground stem nodes, so that the collected specimens are valuable to plant taxonomists.

When collecting specimens, fill in one by one with reference to the format of the collection records, and immediately hang the collection number of the small label on the plant specimens. At the same time, pay attention to check whether the collection number on the collection record is equal to the number on the small label, and whether the situation on the record is the collected specimen. This is very important, if there is an error, it will lose the value of the specimen and even affect the identification of the specimen.

The number of acquisition numbers should be small labels, and the number of small labels should be consistent with the number of acquisition numbers.

4. Method of pressing and arranging plant specimens

It is best to suppress the fresh specimens collected on the same day. If time does not allow pressing the next day, the specimens must be pushed to a ventilated place to avoid heat release. The following work must be done when pressing:

(1) Arrange the specimen, and trim a part of the redundant and useless dense branches and leaves on the specimen to avoid covering flowers and fruits.

(2) Numbering The collected plants of the same species shall be numbered, and the numbering shall be consistent with that recorded in the field, and the organs that are easy to change after inhibition shall be recorded in detail.

(3) When pressing, use a wooden splint as the bottom plate, spread 4-5 layers of papyrus, then lay the sorted specimen flat on papyrus, flatten the branches and leaves of the specimen, and spread 2-3 papyrus to separate the specimen from papyrus. A piece of toilet paper can be used to put common herbs or branches and leaves. If some flowers and fruits are too big, such as magnolia, dahlia, Ficus pumila, etc. When pressed, it is easy to produce gaps near flowers and fruits, which leads to some leaves curling. In this case, it is best to fill the gap with thick papyrus paper, for example, put all the branches and leaves of the specimen in wooden clips and make them under the same pressure. In addition, it must be noted that the head and tail of the specimen should be reversed when laying toilet paper, so that the specimen and toilet paper in the wooden clip are neat and flat. When overlapping to a considerable height, ropes should be tied at both ends of the wooden clip.

(4) For newly pressed specimens, dry paper should be changed at least 1-2 times a day. These dry papers are preferably damp and hot after sun exposure or fire, and their heat can be slightly increased with the gradual drying of plant specimens. At the same time, the following work must be done when changing paper:

A. When changing paper at first, the leaves on the specimen must be turned over, so that there are two kinds of leaves on the specimen, the ventral side and the dorsal side. If the leaves are turned over after drying, they will be broken and put on. At this time, if you think that the branches and leaves of the specimen are too dense, you can properly sparse a part.

B. When changing paper for the first time, the covered branches, folded leaves and flowers must be carefully opened, which is the key to suppress the quality of the specimen and must be paid attention to.

C. In the process of changing paper, if leaves, flowers and fruits fall off or are found to be redundant, they must be put into paper bags and pressed together with the specimen, but the same number as the specimen must be written on the outside of the paper bag, so that the specimen will not be confused.

If the pressed specimens are to be dried quickly and keep their original colors, it is necessary to replace the hot papyrus paper once or twice on the second to third day after the initial pressing, so that all specimens can be dried for about 6-8 days.

In addition, the vegetative organs of Orchidaceae, Araceae, Sedum and other plants are thick and fleshy, so they can continue to grow without drying up. Therefore, it is best to boil these plants in boiling water for about half a minute to 1 minute to kill their outer cells and promote their drying. Another example is some species of Euphorbiaceae plants, although they often change paper, they are easy to lose their leaves. Only bare branches are left after pressing, and the original shape of the specimen is gone. In this case, the specimen can be soaked in boiling water to kill its mesophyll cells before pressing, but it should be noted that the flowers cannot be soaked in boiling water when using this method.

(two) the production and preservation of plant specimens (wax leaf specimens)

A qualified plant specimen needs to go through basic processes such as pressing, disinfection, paper feeding and specimen preservation, as follows:

1. disinfection: generally, it is disinfected with saturated solution of mercury chloride (HgCl2). The preparation method is to dissolve 2~3g of mercuric chloride in1000 ml of 70% alcohol. During disinfection, you can spray the disinfectant directly on the specimen with a sprayer, or you can put the specimen in a big basin, dip it in the disinfectant with a brush and gently brush it on the specimen. You can also pour the disinfectant into the basin and soak the specimen in the disinfectant. You can also put the specimen in a disinfection room and a disinfection box, put dichlorvos or the mixed solution of carbon tetrachloride and carbon disulfide in a glass dish, and kill the insects or eggs on the specimen with poisonous gas for about 3 days. Mercury mercuric chloride is highly toxic, so direct contact with samples should be avoided during disinfection to prevent poisoning. After disinfection, the specimens should be placed on the specimen rack and pressed dry before they can be placed on paper.

2. Paper on the table: Use white table paper (8 pieces of whiteboard paper or cardboard, about 39 ×29cm) and lay it flat on the table. Then put the sterilized specimen on the table paper and set the position. The lower right foot and the upper left foot should be left in the position where the name label and field record label are attached. At this time, you can use a knife to cut several small longitudinal openings at appropriate positions along the various parts of the specimen, and then use a tough white paper strip to pass through the longitudinal openings, tighten them from the back and stick them firmly on the back with glue. This method of putting paper on the stage is beautiful and firm, which is much better than the method of sticking it in front. For too small specimens (such as duckweed) or fallen flowers, fruits, seeds, etc. When it is inconvenient to fix it with paper strips, you can put the specimen in a folded paper bag and stick the paper bag on the surface paper so that you can open the paper bag at any time during observation.

3. Preservation and preservation of wax leaf specimens: All higher plant specimens that have been papered and put into paper bags should be kept in the specimen cabinet after being officially named. In order to reduce the wear and tear of the specimen, it is best to wrap the specimen in kraft paper according to its genus, and write your signature in the upper right corner of the envelope for easy reference.

Specimen cabinets are made of iron, generally with two sections and four doors. Camphor insect repellent should be put in the specimen cabinets to prevent insects from eating.

The arrangement of wax leaf specimens in the specimen cabinet is generally arranged according to the classification system.