Subsequently, the authors conducted a carefully analysis and comparison of the morphological characteristics of the unknown Curcuma with all related species in the genus Curcuma. They determined that the unknown Curcuma did not exhibit any resemblance to any known species. Consequently, it is determined that the unidentified Curcuma is a new species and was identified as Curcuma sirirugsae Saensouk & Rakarcha in this description. A description of the morphological characteristics is provided together with information on their distribution, ecological data, flowering and fruiting periods, vernacular, etymology, and conservation status. It also includes a study of the closest species and an updated key to the 25 species of the Curcuma subgenus Curcuma that have been recognized to be present in Thailand.
Materials and MethodsIn 2023, while conducting research in Sukhothai province, located in the northern part of Thailand, the first author collected unidentified Curcuma specimens. This species was found in the deciduous forest located in the limestone hills of Si Samrong district. The plant specimens were meticulously preserved in a solution of 70% ethyl alcohol, while voucher specimens were officially deposited at QBG. The current research involved a thorough examination of the available published literature on Curcuma, with specific emphasis on the subgenus Curcuma. The research involved the analysis of type materials and protologues of all documented species within this subgenus. Furthermore, the study primarily focused on the geographic distribution of these species in Thailand, along with Myanmar, China, Laos, and Vietnam. Additionally, the research procedure also involved considering any available digital resources related to this topic matter. The morphological characteristics have been evaluated and documented employing fresh materials, spirit specimens, and herbarium specimens, uses a stereomicroscope. The preliminary evaluation for conservation