Background and aims – Keraunea is a Brazilian endemic genus that has sat uncomfortably in Convolvulaceae where it was placed due to an enlarged and adnate fruit bract typical of Neuropeltis. A recent molecular phylogeny suggested that two of its five morphologically almost identical species actually belong to two different families, Malpighiaceae (superrosids) and Ehretiaceae (superasterids). Later studies have demonstrated that Keraunea effectively belongs to Ehretiaceae, but the proposal of one species belonging to Malpighiaceae has remained problematic. In this study, we re-assess this hypothesis, discuss the issues that have led to this assumption, and offer insights on the importance of carefully using herbarium collections and incorporating morphological evidence in systematic studies. Material and methods – Sequences of matK, rbcL, and ITS for all 77 currently accepted genera of Malpighiaceae, K. brasiliensis and Elatinaceae (outgroup) were compiled from GenBank and analysed with Maximum Likelihood and Bayesian Inference criteria for nuclear, plastid and combined datasets. Additional database and herbarium studies were performed to locate and analyse all duplicates of the holotype of K. brasiliensis to check for misidentified or contaminated material. Key results – Our examination of expanded DNA datasets and herbarium sheets of all K. brasiliensis isotypes revealed that a mistake in tissue sampling was, in fact, what led to this species being proposed to belong in Malpighiaceae. Kew’s isotype had a leaf of Malpighiaceae (likely Mascagnia cordifolia) stored in the fragment capsule, which was sampled and sequenced instead of the actual leaves of K. brasiliensis. Recently published studies have settled the placement of Keraunea in Ehretiaceae (Boraginales) and proposed three additional species. Conclusions – DNA sequences can be helpful in classifying taxa when morphology is conflicting or of a doubtful interpretation, with molecular phylogenetic placement being established as a popular tool accelerating the discovery of systematic relationships. Nonetheless, molecular techniques are also susceptible to methodological mistakes, which necessitates building a solid foundation of plant morphology and taxonomy to avoid artefacts in phylogenetic studies.

Argyreia Lour. is one of the most taxonomically complex genera of the morning glory family (Convolvulaceae). The number of named species is now 135, and new species are regularly being described. There are several species complexes that are morphologically similar and difficult to tell apart. Therefore, the aim of this study is to explore the species identification criteria for Argyreia, especially new sources for taxonomically informative characters. Ten accessions representing three morphologically similar Argyreia operational taxonomic units (OTUs) were collected and their anatomical characters were investigated using the leaf peeling technique and paraffin sectioning method. Anatomical character states were analyzed using two phenetic analysis methods: clustering analysis (CA) and principal component analysis (PCA). Three distinct clusters were clearly separated in both PCA and CA at the internal similarity coefficient of 0.48 with a high R-value of 0.89757. Nineteen effectively distinguishable character states were derived from the high loadings of the first two components. In conclusion, two of the separated groups were matched with known species, and the third separated group is here delineated as a new species. Therefore, a new species, Argyreia gyrobracteata Traiperm & Chitchak, is described and illustrated together with ecological data and a preliminary conservation assessment.

Background: Kaempferia is a genus belonging to the ginger family. Currently, this genus is comprised of about 63 species, mainly distributed from India to Southeast Asia. During our fieldwork, a new species of Kaempferia was found in Chon Buri Province, Thailand. The objective of this article was to provide morphological evidence and confirm its relationships in Kaempferia through molecular phylogenetic analysis. Methods: Plant samples were collected from field sites and investigated by conventional taxonomy and molecular techniques. The phylogenetic trees were reconstructed using the maximum likelihood criterion and Bayesian inference. The morphological evolution was also examined to elaborate the relationships among representative Kaempferia taxa. Results: Kaempferia chonburiensis from southeastern Thailand is described and illustrated based on morphological features and its taxonomic placement was confirmed by molecular phylogenetic analyses and morphological evolution. An identification key is provided for the new Kaempferia species occurring in Thailand. Conclusion: Kaempferia chonburiensis is a new enumerated species of Kaempferia from Thailand.

Background and aims – Keraunea is a genus recently described in Convolvulaceae, though it has sat uncomfortably in this family. A recent molecular phylogenetic study suggests that its two morphologically almost identical species actually belong to different families, Malpighiaceae (Superrosids) and Ehretiaceae (Superasterids), although with little-to-no morphological evidence to support it. Material and methods – Sequences of matK, rbcL, and ITS for all the 77 currently accepted genera of Malpighiaceae, K. brasiliensis and Elatinaceae (outgroup) were compiled from Genbank and analysed with Maximum Likelihood and Bayesian Inference criteria for nuclear, plastid and combined datasets. Additional database and herbarium studies were performed to locate and analyse all duplicates of the holotype of K. brasiliensis to check for misidentified or contaminated materials. Key results – Our examination of expanded DNA datasets and herbarium sheets of all K. brasiliensis isotypes revealed that an error in tissue sampling was, in fact, what led to this species being placed in Malpighiaceae. Kew’s isotype had a leaf of Malpighiaceae (likely from Mascagnia cordifolia) stored in the fragment capsule, which was unfortunately sampled and sequenced instead of the actual leaves of K. brasiliensis. Conclusions – DNA sequences can be helpful in classifying taxa when morphology is conflicting or of a doubtful interpretation, with molecular phylogenetic placement becoming a popular tool that potentially accelerates the discovery of systematic relationships. However, good knowledge of plant morphology is essential for formulating the phylogenetic hypotheses to be tested and for a critical re-interpretation of the results in the context of biological information of the species or families. Thus, these techniques are, much like any others, prone to methodological errors. We highlight the crucial need to observe plant morphology alongside molecular phylogenetic results, particularly when the new hypotheses are in disagreement with the existing classification and at risk of incurring gross taxonomic mistakes.