How to learn plant identification systematically?

According to personal experience, the steps are as follows: 1. Read through a botany textbook, preferably an old one. Lu Xu's Green Paper is good, and the new books are more and more rough in classification, especially the foreign undergraduate textbooks, which are basically worthless. After reading this book, you should know the fancy drawings, the various structures of flowers and inflorescences, the basic principles of division, and the type species of major subjects. You should be able to recognize them when they are reduced to ashes. If so, you have the most basic theoretical knowledge. 2. Start identifying plants on the spot. At this time, what you need is a local flora or a botanical illustration that you can take with you. It's useless if the scope is small, Chinese flora is useless, and botanical experiments are basically useless. This step is the same as the previous step, and there is no need for teachers to bring it or record it. You just need to carefully recognize all the plants around your living environment every day. If you can go out and see a tree you don't know, you can't eat or sleep well, and you can basically reach one or two hundred species. After the first two steps of training, you can say that you have already started. The next step is to get in touch with more plants, which can be achieved through field practice, traveling abroad or visiting botanical gardens. In this step, you need to bring your camera and notebook and learn to take notes. In the wild, facing 50 species around you at the same time, it is very inefficient to turn over books at will. What you have to do is to record the characteristics of each plant according to your knowledge, and then identify it with the help of classification tables, reference books and other great gods after returning to your residence. This step is very important, and your exact understanding of each family and genus is formed at this stage. Usually, you will find that there is a serious contradiction between book knowledge and practical experience, and you will also come into contact with many general textbooks. After this stage, you will know 300 to 500 kinds of plants and successfully promote your talent. At this level, you have surpassed most undergraduates majoring in biology, except for some abnormal taxonomy (such as Orchidaceae). Not only are the green plants in the whole city out of your sight, but you can also be a good tour guide when you go to the General Botanical Garden. At this time, if you want to go further, you need to learn a higher level theory-systematic taxonomy (Gurcharan Singer's Plant Systematic Taxonomy: Comprehensive Theory and Method is highly recommended as an introductory reading in this field). You will get to know john hutchinson and Tashtazyan, learn about taxonomic units above families, appreciate the charm of the plant kingdom again from the perspective of phylogeny, and then have a better answer to the previous stage's problems, and even have your own opinions on some unresolved taxonomic problems. At this stage, you should read Flora of China carefully, and you will find that with enough field experience, this masterpiece is no longer boring, but becomes very interesting.