Juglans species have considerable ecological and economic value worldwide. In China, Wenwan walnuts have been collected by aristocrats and noblemen for more than 2000 years. As a diversity center of Asian Juglans, five species are widely distributed in China. The most famous of these is Mahetao (J. hopeiensis), which is an uncharacterized species that is mostly cultivated. Wild J. hopeiensis individuals are very rare and are endemic to Hebei province. Because of the minimal variations in previously used molecular markers and the heterogeneity between chloroplast and nuclear genomes, determining the phylogenetic relationships among the Juglans species has been challenging, and has hindered subsequent evolutionary inferences. In this study, we collected enough materials for both cultivated and wild Mahetao to construct well-resolved phylogenetic trees for Asian Juglans species. We used a high-throughput genome-wide restriction site-associated DNA sequencing method. Consequently, the identity of J. hopeiensis has been clearly resolved. Our results indicate that J. hopeiensis is a hybrid of J. regia and J. mandshurica. However, J. hopeiensis, J. regia and J. sigillata should be considered as a single species from section Juglans. Additionally, J. ailantifolia, J. cathayensis, and J. mandshurica likely represent one species from section Cardiocaryon according to morphological and molecular studies. These results are supported by population structure analysis and morphological comparison. We propose that J. hopeiensis trees growing in the wild should be conserved because of the economic value of their nuts. These trees may be of particular importance to impoverished communities. Furthermore, they may serve as a valuable genetic resource relevant for enhancing the production of edible walnuts. The 2b-RAD method is a viable option for future phylogenetic studies of Juglans species as well as other plant species.

South Asia, which is composed of eight countries, including Afghanistan, Bangladesh, Bhutan, India, Maldives, Nepal, Pakistan, and Sri Lanka, is an important global biodiversity hotspot. As a part of the Mapping Asia Plants (MAP) project, we reviewed the history of botanical investigations, floristic works, and publications in this region, as well as the key floras, checklists, and online databases in South Asia. The botanical survey of this region, which began during the 17th century, has two distinct phases: surveys conducted during the British India period and those conducted in the post-British period. The seven volumes of The Flora of British India are the most important contributions to flora research in South Asia because of their wider geographical coverage, which was performed by British botanists. Following on from this, different countries have launched independent floristic surveys. At the country level, Afghanistan, Bangladesh, Bhutan, India, Nepal, Pakistan, and Sri Lanka have completed, or partially completed, their flora surveys at the country level, while Maldives has not yet published its national flora survey. According to currently available information, the approximated numbers of plant taxa for each country in South Asia are as follows: Afghanistan, 5261 (vascular plants); Bangladesh, 3470 (vascular plants); Bhutan, 5985 (flowering plants); India, 21,558 (flowering plants); Maldives, 270 (common plants); Nepal, 6500 (flowering plants); Pakistan, 6000+ (vascular plants); and Sri Lanka, 4143 (flowering plants). Additionally, there are 151 books devoted to the key floras and checklists in South Asia. A total of 1.1 million digital records of specimens from this region can be found on the website of the Global Biodiversity Information Facility (GBIF). However, there are still major gaps and limitations—such as out-of-date publications, national floras that are mainly detailed only in local languages, massive non-digitized specimens, and the lack of a comprehensive online database or platform—which should be addressed in terms of their global applications.

Ophiopogon ximengensis, a newly described species from Yunnan Province, SW China, is illustrated herein. Characterized by its strongly recurved tepals O. ximengensis resembles O. griffithii originally described from the same region. However, it is distinctly identifiable by its shorter and broader, more distinctly inequilateral leaf blades, denser inflorescences usually with a tuft of 2 or 3 clustered flowers in axils of bracts and shorter internodes, and more strongly recurved, internally unspotted white perianth lobes. Additionally, we provide notes on its habitat, conservation status, phenology, and taxonomic relationships with related species.