Taxon delimitation and identification are important in many areas of biology, especially in taxonomy and conservation. Taxonomic treatment is required to establish and justify recommendations in conservation biology for the group being considered. Imperfect and controversial taxonomy can undermine conservation assessment. We studied 71 populations; 665 individuals corresponding to the morphology of the Rosa sericea complex (including six taxa, one of which has extremely narrow distributions) were collected from sympatric, parapatric, and allopatric populations distributed in China. This study aims to investigate whether the complex species are macromorphologically different species and evaluate the rare taxa of the complex for conservation priority. The morphological characters and principal component analysis (PCA) of the R. sericea complex showed that the complex species have overlapping characters but can distinguish morphologically. The species of R. sericea complex systematics status based on previous DNA sequencing is controversial. The ecological habitat’s current morphological characters only delimit the R. morrisonensis (in Taiwan). To evade mistakes in species conservation, we recommend that taxonomical knowledge be needed to ensure success in protecting target species. Thus, the complementarity of systemic and conservation assurance makes conservation actions more necessary for the complex’s rare taxa. The ecological niche modelling (ENM) results showed that habitats of these conspecific taxa would be shrunken. With the presence of snapshots in time, the geography of taxa might decrease rapidly in representative entirely of the Geographic space (G-space) and Environmental space (E-space) that such taxa are bright to inhabit. So far, the significant inferences meant for the niche occupy the most incredible comparative research, taking the impermanent nature of taxa distributions and undertaking that such species are at a state of stability. If the artificially identified species (rarely distributed) are based on morphological identification, they must be conserved.

In this research, the fruits and seeds' surface morphological features and their taxonomic significance were determined. Additionally, useful traits for delimitation of taxa of Rosa sericea complex were studied. In this research, three taxa of the complex R. sericea, R. omeiensis, and R. sikangensis have been studied. A total of 41 populations and 130 specimens of seeds, and 35 populations and 168 specimens of fruits from 10 different geographical regions of southwest China have been examined. The surface micro‐morphological characters of the seeds have been studied through scanning electron microscopy to distinguish important characteristics of the complex taxa. Forty‐four different qualitative and quantitative characteristics were observed. Principal component analysis was used to simplify and elucidate the relationship between the studied characters of different population based on the morphology of fruits and seeds' features. Moreover, the numerical taxonomic characters and their variation with elevation have been studied in these species. The most interesting characters observed on the surface of the seeds were stomata, and trichomes, for which density was more at the dorsal and ventral parts, while rarely present on the lateral parts. The fruits and seeds' surface morphology of the studied species was complicated and some variation in the characters, that is, persistent calyx shape, the shape of fruits and seeds, stomata shape, and trichomes size were found significant for delimitation of taxa in the complex. The purpose of this study is to identify the taxa of R. sericea complex based on fruits and seeds' morphological characters, and identification keys.

As the distribution center of Rosa in the world, China has abundant wild germplasm resources, which can contribute to the breeding of modern roses. To explore the potential value of wild roses distributed in the Sichuan–Tibet region, solid phase microextraction (SPME) and gas chromatography–mass spectrometry (GC–MS) were used to determine the volatile organic compounds (VOCs) in Rosa willmottiae flowers at three flowering stages (bud stage, initial flowering stage, full flowering stage). Meanwhile, we compared the VOCs of R. willmottiae with different phenotypes (double flowers and single flowers). A total of 74 volatile compounds were identified. The results show that the essential substances belong to alcohols and terpenoids. The main volatile organic compounds are 2-phenyl ethanol (20.49%), benzyl alcohol (10.69%), β-maaliene (8.66%), geranyl acetate (8.47%), and (+)-α-long pinene (6.127%). Different flowering stages had great influence on the volatile profile, from the bud stage to full flowering stage; the content of terpenoids released decreased by 6.17%, whereas alcohols and esters increased by 8.58% and 11.56%, respectively. The chemical diversity and the content of the main components with a different phenotype were not significantly different. Our result will provide a theoretical basis for the development and utilization of Rosa willmottiae in Sichuan and Tibet.