Taxonomical clarification of Dracaena cambodiana Pierre ex Gagnep., the source plant of Chinese “Resina Draconis”

“Resina Draconis”, also known as “Dragon’s Blood Resin” or “Yunnan Hongyao”, is red resin produced by the trunks of Dracaena species. Chinese “Resina Draconis” is derived from phenolic resins of D. cambodiana Pierre ex Gagnep. and D. cochinchinensis (Lour.) S. C. Chen. Due to taxonomic ambiguities between D. cambodiana and D. cochinchinensis in Chinese floras, there has been confusion in the literature regarding the source plant of Chinese “Resina Draconis”. To resolve this, we examined the protologue and type materials of D. cambodiana, D. cochinchinensis, and D. angustifolia (Medik.) Roxb. and reconstructed the plastome phylogenies of 19 Dracaena species from 33 accessions. The plastome phylogenies strongly supported the division of these 19 Dracaena species into three clades. Species capable of producing phenolic resins were found in CladesⅠand Ⅲ, indicating their potential as source plants for “Resina Draconis”. Notably, nine samples of D. cambodiana were not supported as monophyletic, forming two distinct groups: the Yunnan clade (D. cambodiana A) and the Hainan clade (D. cambodiana B). Morphological analysis of the protologue and neotype specimens indicated that D. cochinchinensis could not be differentiated from D. angustifolia, and thus should be considered as a synonym of D. angustifolia. Integrating phylogenetic analyses and morphological characteristics, we determined that D. cambodiana is the primary source plant of Chinese “Resina Draconis”, with D. saposchnikowii Regel from South Yunnan and Dracaena sp. 2 from South Guangxi also contributing to its production. The plastome phylogenies clarified the source plants of “Resina Draconis” and elucidated the genetic relationships within the genus Dracaena, providing important information for the conservation and sustainable utilization of Dracaena germplasm resources.