Oreocharis leveilleana Fedde was collected in Ta-pin in 1910 and published in 1911. The collected location was verified within western Luodian County, Guizhou Province, China. However, there have been no records of the species’ collection for more than 100 years since then. After extensive investigations by our research team on the type locality and its surrounding areas, we found that it is widely distributed in western Luodian County and eastern Wangmo County, Guizhou Province, China. During further research on the original literature, type specimens and type locality of O. leveilleana, the taxonomic position of O. leveilleana, which was once treated as a synonym of O. auricula (S.Moore) C.B.Clarke, was found to have a taxonomic problem. Through morphological research combined with geographical distribution analysis, it has been determined that it should belong to the genus Petrocodon Hance and it is the same species as P. coccineus (C.Y.Wu ex H.W.Li) Yin Z.Wang. According to the regulations and suggestions of the 2018 "International Code of Nomenclature for Algae, Fungi, and Plants (Shenzhen Code)", we propose and confirm a new combination – Petrocodon leveilleanus (Fedde) X.X.Bai & F.Wen and treat P. coccineus as a synonym of the new combination. Due to its unique bright red flowers within Petrocodon, its original Chinese name has been retained.

Oreocharis, Petrocodon, Petrocodon coccineus, new combination, synonym

The genus Oreocharis Benth., established by G. Bentham (1876), belongs to the tribe Trichosporeae, subfam. Didymocarpoideae, Gesneriaceae (Weber et al. 2013). Currently, there are more than 150 recorded species (excluding infraspecific taxa), while China has about 158 taxa (including 15 varieties). These plants are predominantly distributed in the south-western region of China and most parts of southern China, with about ten species distributed in Vietnam, Myanmar, Japan and Thailand (GRC 2023). Oreocharis is a diverse group of plants with various morphologies. There have been significant discrepancies in taxonomic viewpoints amongst scholars in different periods, leading to substantial changes in its systematic position. It was not until Möller et al. (2011), based on molecular evidence and morphological analysis, merged nine genera including Ancylostemon Craib, Opithandra B.L.Burtt, Isometrum Craib, Tremacron Craib, Bournea Oliv., Dayaoshania W.T.Wang, Thamnocharis W.T.Wang, Deinocheilos W.T.Wang, Paraisometrum W.T.Wang and the rosulate taxa of Briggsia Craib into the enlarged concept of Oreocharis, that the systematic revision of this genus was essentially completed. Although the genus Bournea was considered an independent genus again (Chen et al. 2020), further research did not support this view (Lv et al. 2022). The frequent and extensive revisions in taxonomy have led to changes in the systematic positions and scientific names of numerous species, making the study of Oreocharis even more complex (Fu et al. 2019).

Additionally, some early published species were established, based on only one or two specimens, with limited or ambiguous information on their type localities. Furthermore, these species often lack important and valuable taxonomic characteristics and there have been no further collection records or literature after publication. The names and habitats of the type locality of some species have also changed over time, making it difficult to rediscover them. These issues have posed challenges for subsequent taxonomic research. For example, Oreocharis rhytidophylla C.Y.Wu ex H.W.Li was considered a doubtful species due to the lack of descriptive information regarding its floral characteristics. It was not until recently that Zhang et al. (2019) collected flowering specimens from its type locality, confirming it as a natural species rather than a doubtful one.

Oreocharis leveilleana Fedde, first collected in 1910 and described as a new species under the genus Oreocharis in 1911, had not been recorded again for over 100 years. Due to limited specimen and literature records, it was considered a doubtful species (Pan 1987; Wang et al. 1990). Subsequently, it was merged with O. auricula (S.Moore) C.B.Clarke due to the temporary unavailability of additional literature and collection records (Wang et al. 1998). Further, due to the unavailability of molecular data for this species, in the study by Möller et al. (2011), O. leveilleana was still treated as a synonym of O. auricula.

In recent years, our research team conducted a comprehensive survey of the Gesneriaceae in Guizhou Province. In April 2023, during the surveys in Luodian County and Wangmo County, we discovered an interesting species of Gesneriaceae. We observed the living plants and recorded their morphological characteristics. We were very certain that the vegetative organs of this species are morphologically almost identical to the type specimen of O. leveilleana (E00067459). To ensure that our judgement was not mistaken, we confirmed it was O. leveilleana after carefully comparing it with the descriptions in literature and the type specimen. Furthermore, while examining the literature on species in the genus Oreocharis, we found some issues with the current taxonomic position of O. leveilleana. We believe that O. leveilleana should be classified under Petrocodon Hance and that it is the same as P. coccineus (C.Y.Wu ex H.W.Li) Yin Z.Wang. P. coccineus was first published as a new species in 1982 as the type species of Calcareoboea C.Y.Wu ex H.W.Li, which was subsequently transferred to Petrocodon, based on molecular evidence and it has since become a species under Petrocodon (Wang et al. 2011).

We reviewed the original literature and related records of Oreocharis leveilleana and Petrocodon coccineus, including the original literature description, information on type specimens and geographical distribution. In addition, we accessed the digital plant specimens of the E, K, P, IBK, PE, KUN and GXMI collections to check the type specimens and high-resolution images of both species, along with other specimens. The primary sources of original literature are from BHL (www.biodiversitylibrary.org), Tropicos (http://www.tropicos.org), and IPNI (http://www.ipni.org). Additionally, we made multiple visits to the type localities of both species to conduct extensive field surveys and document the growth and distribution of populations. The study was carried out using classical plant taxonomic methods.

We want to thank Stephen Maciejewski, the Gesneriad Society and Michael LoFurno (Associate Professor, Temple University) from Philadelphia, the USA, for their editorial assistance. We are also grateful to the Herbaria mentioned above (E, K, P, IBK, PE, KUN, GXMI) for images/photos of specimens available.