Siphocranion is an oligotypic genus of Lamiaceae, with two species mainly distributed in subtropical China and one of them found also in northeastern India, Myanmar, and Vietnam. Based on field investigation, morphological comparison, and molecular phylogenetic analyses, a new species of Siphocranion from the Sino-Vietnamese border is described as S. flavidum. Bayesian and maximum likelihood analyses on two nuclear ribosomal DNA regions and six plastid DNA regions reveal that S. flavidum is a distinct species in the genus and may be sister to the clade formed by the remaining two species of Siphocranion. Morphologically, the new species differs from S. macranthum and S. nudipes in its strigose stem with dark purple spots, thick papery lamina, significantly larger calyx, pale yellow corolla with tube slightly saccate at anterior side of base.

Critical examination of herbarium specimens (including type materials) has shown that Stranvaesia microphylla described from Vietnam is conspecific with Photinia davidiana var. undulata (≡Stranvaesia davidiana var. undulata), which is widely distributed in China. Therefore, S. microphylla is reduced as a synonymy of P. davidiana var. undulata. Additionally, one new combination has been proposed and one lectotype has been designated here.

Odontochilus napoensis, a new species from southwestern Guangxi, China, is described and illustrated. It is close to Odontochilus inabae (Hayata) T. P. Lin, but can be distinguished by its glabrous ovary, solitary flower, and 2.0–3.5 mm long filaments of flanges. It is also similar to O. nanlingensis (L. P. Siu & K. Y. Lang) Ormerod, but differs by the solitary, not resupinate flower, and light greenish–brown lateral sepals.

Anoectochilus nandanensis, a new species from northern Guangxi, China, is described and illustrated. It is similar to A. emeiensis K. Y. Lang in habit, but distinguished by the size of the plant, leaves and lateral sepals, as well as the flanges of the mesochile.

The genus Exostoma is a group of stenotopic and rheophilic glyptosternine catfishes distributed in South and Southeast Asia. So far, comprehensive studies on mitogenomics referring to this genus are very scarce. In this study, we first sequenced and annotated the complete mitochondrial genomes of Exostoma tibetanum and Exostoma tenuicaudatum—two sympatric congeners from the lower Yarlung Tsangpo River, Tibet, China. The mitogenomes of both species contained 13 protein-coding genes, two ribosomal RNA genes, 22 transfer RNA genes, one light-strand origin of replication, and one control region, with lengths of 16,528 bp and 16,533 bp, respectively. The mitogenome architecture, nucleotide composition, and codon usage of protein-coding genes were almost identical between the two Exostoma species, although some estimated parameters varied. Phylogenetic analysis strongly supported the monophyly of Exostoma in the subfamily Glyptosternae, and Exostoma tibetanum had the closest relationship to Exostoma tenuicaudatum. The divergence time estimation demonstrated that these two species diverged approximately 1.51 Ma during the early Pleistocene, which was speculated to be triggered by the river system changes caused by the uplift of the southeastern Tibetan Plateau. Selection pressure analyses indicated that all protein-coding genes of Exostoma species underwent a strong purifying selection, while minority positive sites from NADH dehydrogenase complex genes were detected. These findings are expected to promote our understanding of the molecular phylogeny of the genus Exostoma and provide valuable mitogenomic resources for the subfamily Glyptosternae