Trivalvaria tomentosa sp. nov. is herein described from Yunnan Province in China. It is easily distinguished from all previously described Trivalvaria species by having tomentose twigs, petioles, abaxial surface of the leaves, sepals and petals. A detailed description for the new species, along with line drawings, photographs, as well as morphological comparisons with similar species, are provided. A phylogenetic analysis was conducted to confirm the placement of this new species within Trivalvaria.

Two accessions of Trivalvaria tomentosa (Y. S. Chen PB-1048, IBSC and J.W. Li 5653, HITBC) was sampled and integrated with data of 61 Annonaceae accessions from previous datasets (Xue et al. 2011, 2018, 2020). The final dataset comprised a total of 63 accessions of Annonaceae with six chloroplast regions (matK, ndhF, psbA-trnH, rbcL, trnL-F and ycf1). The phylogenetic trees were reconstructed using Bayesian Inference (BI) and maximum likelihood (ML). Methods in phylogenetic reconstruction can be refer to Xue et al. (2018, 2020).