The infrageneric classification of the genus Clerodendrum (Lamiaceae) has been highly problematic due to different concepts and subdivisions being applied to the treatment of Asian, Australian, and African species. Earlier molecular phylogenetic studies based on Sanger sequencing and limited sampling have indicated that previous morphology-based infrageneric classifications are not congruent with the phylogeny due to morphological convergence in many lineages. Advances in high-throughput DNA sequencing provide more information allowing more robust phylogenetic reconstruction at larger scale. We present the first comprehensive phylogenetic study of Clerodendrum that includes representatives of all previously recognized infrageneric taxa and using targeted sequencing data obtained from the Angiosperms353 enrichment to resolve the phylogenetic relationships. In agreement with previous phylogenetic work, our phylogeny shows that Asian and Australian species form a sister clade to an African Clade. Clerodendrum is monophyletic with the exclusion of some tropical coastal species, including some Australian species, which fall within a clade containing Volkameria and New World genera. We recognize two subgenera: subgen. Clerodendrum for Asian and Australian species and the new subgen. Afroclerodendrum for African and Malagasy species. Our findings support an infrageneric classification of Clerodendrum with a total of 13 sections based on molecular phylogenetic evidence and morphology that clearly accommodate the Asian, remaining Australian, and African species. Of these, we propose three new sections: sect. Albiflora, sect. Fortunata and sect. Megaflora for clades presenting unique morphological characters. The sectional classification and taxonomic consequences are discussed.

Two new Friesodielsia species (Annonaceae) from Peninsular Thailand, F. betongensis and F. chalermgliniana, are described and illustrated. The addition of these raises the total number of Friesodielsia species in Thailand to 18. A conservation assessment for each new species and an identification key for all Thai species are provided.

Six new species of Friesodielsia (Annonaceae) are described and illustrated, seven species are documented for Thailand for the first time, and Oxymitra fornicata (Roxb.) D. Das var. glabra is raised to species rank as Friesodielsia andamanica. These additions bring the species diversity of Friesodielsia in Thailand to 16 species. A key to the Thai species is provided.

During botanical expeditions focused on the study of Annonaceae in Thailand, specimens resembling Friesodielsia glauca were collected from the lower part of peninsular Thailand but were believed to differ from that species in vegetative, flower, and fruit characters. A morphological investigation of the new specimens and species complex was conducted. Specimens (including types of F. glauca and similar species collected from Thailand and adjacent regions) were examined in the following herbaria: A, BK, BM, BKF, E, K, KEP, KKU, L, PSU, QBG, SING, and US. As a consequence, the new species Friesodielsia parvimitra, endemic to peninsular Thailand, is described and illustrated. The conservation status of the new species was provisionally assessed as Critically Endangered (CR, B2ab(iii)) following the IUCN’s guidelines. In addition, F. argentea, previously regarded F. glauca, is reinstated here as a distinct species based on several morphological differences and is reported as a new record from Thailand. Photographs, line drawings, and a revised key to F. glauca and similar species are presented.

Fruits and endocarps of 21 species within the genus Premna (Lamiaceae) in Thailand were examined using light (LM) and scanning electron microscopy (SEM) to evaluate taxonomic relevance. Overall, mature fruits were classified into two types: fully developed mericarp (fruit type I) and partly developed mericarp (fruit type II), with three shape patterns: broadly obovoid, narrowly obovoid, and clavoid. Fruit size ranged from 1.52 to 7.48 mm in length and 0.98 to 7.71 mm in width. In LM investigations, the endocarps were classified into three types based on the presence and shape of the protruding structure: saccate-like (protrusion type I), thorn-like (protrusion type II), and no protrusion (protrusion type III). The examination of endocarps under SEM showed that they consist of multilayers of sclerenchyma cells. The shape of the sculpturing cells on the endocarp surface can be divided into two patterns: irregular tetragonal and polygonal, with distinct or obscure straight cell faces. The morphological comparison and phenetic analyses using factor analysis of mixed data (FAMD) show that fruit and endocarp characteristics of Premna hold significant taxonomic value for distinguishing certain related species and classifying within the genus in Thailand. From the first two FAMD dimensions, fruit shape, shape of sculptured cells on the endocarp, and protrusion type of the endocarp are considered as the most significant contributing variables. The findings also support the reinstatement of species previously synonymized with P. serratifolia, namely P. cordifolia, P. paniculata, and P. punctulata.

A taxonomy of the genus Phyllodium Desv. in Cambodia, Laos, and Vietnam is presented. The plant specimens collected from the fields and herbarium specimens kept at Asian and European herbaria are examined. The IUCN conservation status of each species at regional and national levels is assessed. Five species are enumerated, viz., Phyllodium elegans (Lour.) Desv., P. kurzianum (Kuntze) H.Ohashi, P. longipes (Craib) Schindl., P. pulchellum (L.) Desv., and P. vestitum Benth. Lectotypification of two names, Desmodium longipes Craib and D. tonkinense Schindl., is performed. A key to the species, description, distribution, ecology, phenology, vernacular names, full list of specimens examined, and photographs are provided. The conservation status of five Phyllodium species varies across Cambodia, Laos, Vietnam, and Indochina. Phyllodium elegans and P. pulchellum are consistently Least Concern (LC) in all regions. Phyllodium kurzianum is Data Deficient (DD) in Laos, Near Threatened (NT) in Vietnam, and LC in Indochina. Phyllodium longipes is EN in Cambodia but LC elsewhere. Phyllodium vestitum is NT in Cambodia, Vulnerable (VU) in Laos and Vietnam, and LC in Indochina. The taxonomic information provided in this work will contribute to the advancement of the Flora of Cambodia, Laos, and Vietnam and the conservation status of each species proposed in this paper can be used for future conservation planning.