According to the investigation, we recorded a total of 396 species of medicinal plants belonging to 116 families and 295 genera (see Additional file 1: Table S1). In the family distribution, Fabaceae has the most significant number of species, including 29 species, followed by Asteraceae and Rubiaceae, both with 21 species; In terms of genera, Ardisia contains the most considerable number of species, including eight species, followed by Bauhinia and Ficus, containing with six species and five species respectively. Among the recorded herbs, 22 families include more than five species, with 235 species, accounting for 59.34% of the total species; 44 families contain 2–4 species, with 111 species, accounting for 28.03%, while 50 single-species families account for 12.63%. At the genus level, there are three genera with more than five species, with 19 species, accounting for 4.80% of the total species; 44 genera with 2–4 species, with 150 species, accounting for 37.88%, and 227 single-species genera, accounting for more than half of the whole species (57.32%).

Generally speaking, the medicinal plants used around the Guangxi Fangcheng Golden Camellias national nature reserve are mainly concentrated in multi-species families, which is the cluster distribution at the family level. In contrast, these plants are primarily distributed in single-species-genera and scattered at the genus level. It reflects that the residents in this area have diversity in the use of medicinal plants, and the relevant traditional knowledge is prosperous.

As for the life forms, among these traditional medicinal plants, herbs account for 38.9%, shrubs take second place, accounting for 26%, and trees and vines account for 17.7% and 17.4%, respectively. More than 93% of the medicinal plants used in this area come from the wild environment around the Guangxi Fangcheng Golden Camellias national nature reserve (369 species). There are only 27 cultivated species, most of which have local uses other than medicine. For example, some cultivated plants are mainly used for food, including Citrus maxima, Clausena lansium, Dimocarpus longan, etc., and some plants are used mainly for ornamental purposes, such as Agave sisalana and Alstonia scholaris.

The medicinal parts of the recorded plants were divided into ten categories: whole plant, branches, underground part (root, tuberous root, rhizome, tuber), leaf (old leaf, tender leaf), stem (vine, transverse stem, stem pulp, old stem, bulb), fruit (seed, fruit, pericarp, seed, melon pulp), bark (root bark), shoot, flower (flower bud, inflorescence), other (camphor, sap, gum, nutrition bulb) and so on. As shown in Fig. 2, the use of whole plant (120 species, 25.59%), branches and leaves (116 species, 24.73%), and roots (101 species, 21.54%) as medicinal parts accounted for the vast majority, significantly higher than other types. As the whole plant is used as the largest proportion of medicinal plants, which contains a large number of herbaceous plants, the general herbaceous plants are small, and their use is often in the form of whole plants. In addition, the higher frequency of utilization of the entire plant, branches, and leaves is also related to the fact that local people like to use plants for external medicinal bathing. The underground part also accounts for more because, according to the local tradition, the root of the plant, especially the root tuber, is considered to be the most effective part, and the local people like to give priority to the use of the root, and its primary use is often decoction or making medicinal wine. Among the recorded plant species, there are also many uses and multiple utilization parts of one plant, reflecting the rich knowledge of local medicinal plants.

The medicinal parts of recorded plants

The diseases treated by medicinal herbs locally are divided into 13 categories, as shown in Figs. 3 and 4 [19]. After analysis, we found that in terms of the types of diseases targeted by medicinal plants, the trend of medicinal plants sold in urban areas was consistent with that of plants investigated in villages around the reserve. Combined with the interview's contents, we found that the herbs sold by urban medicine shops were mainly purchased from local medicine collectors, and these wild medicinal plants were collected around the nature reserves. This is probably one of the main reasons why medicinal plants in both urban areas and villages target similar diseases.

The diseases targeted by medicinal plants

The ICF value of diseases targeted by medicinal plants

In addition, according to Fig. 3, herbs for rheumatism account for the highest proportion, followed by muscle system diseases and skin-related diseases, which are closely related to the local climate and livelihoods. As the local people are located in the mountain areas, the daily livelihood is primarily manual labor, which is very heavy; coupled with the long-term hot and humid local climate, rheumatism, muscle system diseases, and skin diseases are prevalent. In addition, herbs for treating respiratory diseases also account for a high proportion (50 species), especially those for cough. In the coastal areas of Fangcheng, the rainy season is very long, during which the weather in the rainy season changes significantly; the alternation of hot and cold temperatures particularly easy to causes colds, a major cause of cough. The rainy season is a period of frequent coughing, which could further cause many bronchial diseases.

The value of ICF is in the range of 0–1. The greater the ICF value, the more significant difference in the use of plant species when treating a specific disease; otherwise, it is more concentrated. According to our analysis (Fig. 4), the ICF values of all the medicinal plants we recorded are higher than 0.6. The ICF shows that the use of local medicinal plants and related knowledge is very diverse, so the local people have more choices in treating diseases. Among them, the species for treating gynecological diseases are relatively concentrated and consistent. However, in this study, we have recorded fewer amounts of plant species to treat gynecological ailments, which may also be related to the lower ICF.

The methods of use are divided into four categories: therapeutic diet, internal administration, medicinal bath, and external use. Among the methods of use, the proportion of boiled water washing (medicinal bath) is the highest, the local climate is hot all year round, and the rainfall is abundant, which provides ideal conditions for the growth of local plants but also brings dampness and poison to the residents. The medicinal bath for disease prevention and treatment formed by the villagers around the natural reserve is a relatively safe and convenient form that belongs to a prominent local feature and has significant research value. Moreover, the medicinal bath has a good effect on muscle relaxation and treating rheumatism and skin diseases. Therefore, in the analysis of the usage of medicinal plants, medicinal bath accounts for the highest proportion, which also has a lot to do with the local natural environment and the physical livelihood of the local people.

In addition, there is a high proportion of decoction, which tends to deal with more diverse diseases, such as digestive diseases, metabolic diseases, etc. Similarly, the ratio of external use is also very high, and plants are usually mashed and applied to the affected area, which is generally used to treat skin diseases. The frequent occurrence of skin diseases also has a lot to do with the hot and humid climate of the area. On the other hand, diet therapy is the least, generally used for brewing wine or cooking directly (Table 1).

The RFC indicator is used to see how potentially important the plant species is for local people. Some plants have high RFCs in both urban areas and villages, including Melicope pteleifolia, Clerodendrum cyrtophyllum, Lygodium flexuosum, Elephantopus scaber, Artemisia argyi, Plantago asiatica, Centella asiatica, Grangea maderaspatana, Liquidambar formosana (Fig. 5). The plant species we listed above are closely connected to local people's daily lives and are potentially vital to them. In addition, those high-RFC plants grow widely in local wild environments and with large biomass. The local people's choice of herbal medicine is also scientific. For example, the plants with high RFC in this study are typical and famous ethnic medicine and also appear in some other ethnobotanical cases, such as the most common medicinal herb, A. argyi [20]. There are also many phytochemical and pharmacological studies to verify the efficacy of these plants, such as M. pteleifolia, which has the highest RFC [21]. Pharmacological studies have shown that crude extracts from M. pteleifolia exhibit anti-inflammatory, antibacterial, anti-tumor, liver protective, antihyperlipidemic, and hypoglycemic effects [21].

The RFC values of recorded medicinal plants (A. Melicope pteleifolia, B. Clerodendrum cyrtophyllum, C. Lygodium flexuosum, D. Elephantopus scaber, E. Artemisia argyi, F. Plantago asiatica, G. Centella asiatica, H. Grangea maderaspatana, I. Liquidambar formosana)