A new species of cinnamon tree has been discovered in Guangdong Province, China, expanding scientists' understanding of the diversity and evolution of the genus Cinnamomum. The newly identified species, Cinnamomum fasciculatum Deng.S.W. & Wang.R.J., was found to have a unique inflorescence structure that has never been reported in sect. Camphora.

The genus Cinnamomum Schaeff. (Lauraceae) comprises approximately 250 species widely distributed across tropical and subtropical Asia and the western Pacific. Traditionally, Cinnamomum s.l. is divided into sect. Camphora Meisn. (ca. 20 species) and sect. Cinnamomum (ca. 230 species). Sect. Camphora is distinguished by its alternate, pinnately veined or trinerved leaves, domatia usually present in the axils of lateral veins, and perulate buds.

In September 2024, Dr. DENG Shuangwen from the Plant Science Research Center at the South China Botanical Garden (SCBG) of the Chinese Academy of Sciences (CAS) discovered a plant specimen suspected to belong to a previously unknown species of Cinnamomum sect. Camphora in the Guangdong Jiangmen Gudoushan Provincial Nature Reserve.

Through detailed morphological comparisons and molecular phylogenetic analyses, the researchers confirmed that the specimen represented a new species, which they named Cinnamomum fasciculatum Deng.S.W. & Wang.R.J.

The findings were recently published online in the journal PhytoKeys.

C. fasciculatum can be readily distinguished by its obovate to obelliptic leaves with an obtuse apex (vs. elliptic-ovate leaves with an acute or shortly acuminate apex in C. parthenoxylon), and most notably by its subterminal inflorescences arranged in the axils of cataphylls below the terminal vegetative bud, sometimes also on axillary brachyblasts (vs. axillary or lateral inflorescences in C. parthenoxylon).

In terms of phenology, C. fasciculatum flowers from June to July, distinctly later than the March-May flowering season of C. parthenoxylon. The most distinctive feature of C. fasciculatum is its subterminal inflorescence position: the thyrsoid inflorescences are subtended by caducous bracts rather than leaves, resembling a miniature version of the flowering branches in some sect. Camphora species. This inflorescence structure is reported for the first time in sect. Camphora.

Flowering branch of Cinnamomum fasciculatum (Image by ZHANG Weiping)

Currently, C. fasciculatum is known only from two populations in the Xinhui District and Taishan City of Jiangmen, Guangdong, both of which are located within the Guangdong Jiangmen Gudoushan Provincial Nature Reserve.

According to the researchers, the discovery highlights the importance of biodiversity surveys in protected areas and provides new insights into the diversity of sect. Camphora.

This study was supported by the Guangdong Flagship Project of Basic and Applied Basic Research, the Science & Technology Fundamental Resources Investigation Program, and the National Wild Plant Germplasm Resource Center.

Fruiting branch of Cinnamomum fasciculatum (Image by ZHANG Weiping)