This study addresses the longstanding absence of a comprehensive phylogenetic backbone for the apple tribe Maleae, a deficiency attributed to limited taxon and marker sampling. We conducted an extensive taxon sampling, incorporating 563 plastomes from a diverse range of 370 species encompassing 26 presently recognized genera. Employing a range of phylogenetic inference methods, including RAxML and IQ-TREE2 for Maximum Likelihood (ML) analyses, we established a robust phylogenetic framework for the Maleae tribe. Our phylogenomic investigations provided compelling support for three major clades within Maleae. By integrating nuclear phylogenetic data with morphological and chromosomal evidence, we propose an updated infra-tribal taxonomic system, comprising subtribe Malinae Reveal, subtribe Lindleyinae Reveal, and subtribe Vauqueliniinae B.B.Liu (subtr. nov.). Plastid phylogenetic analysis also confirmed the monophyly of most genera, except forAmelanchier,Malus,Sorbussensu lato, andStranvaesia. In addition, we present a comprehensive taxonomic synopsis ofPhotiniaand its morphological allies in the Old World, recognizing 27 species and ten varieties withinPhotinia, three species and two varieties withinStranvaesia, and two species and three varieties withinWeniomeles. Furthermore, we also lectotypified 12 names and made two new combinations,Photinia microphylla(J.E.Vidal) B.B.Liu andWeniomeles atropurpurea(P.L.Chiu ex Z.H.Chen & X.F.Jin) B.B.Liu.
The diverse members of the genus Daphne are prized for their fragrant flowers. Despite being promising ornamental plants in many countries, genetic information of Daphne is scarce. In this study, the plastomes of four species and one variety of Daphne were sequenced and analyzed. The plastomes were typical and contained a pair of inverted repeat (IR) regions that separated the large single-copy (LSC) region from the small single-copy (SSC) region. With a length ranging from 132,869 bp (D. genkwa) to 174,773 bp (D. championii), 106 to 141 genes were predicted. Comparative plastome analysis of the newly sequenced plastomes with four publicly available Daphne plastomes identified an expansion of the IRs, sequence variations, and mutational hotspots. Phylogenetic analyses indicated that the genus Daphne in its current circumscription is polyphyletic. Daphne genkwa was nested within the genus Wikstroemia, while D. championii was well resolved as sister to Edgeworthia. These findings concurred with results from our study that used nuclear ribosomal internal transcribed spacer sequence data. The conflicts on the molecular placement of D. championii and D. genkwa and the present taxonomic classification in Daphne suggest that a new intergeneric classification system of Daphneae warrants consideration.
Viola huizhouensis (Violaceae), a new species from Xiangtoushan National Nature Reserve of Guangdong Province in China, is described and illustrated. The new species is most similar to V. guangzhouensis, but it can be easily distinguished by its much stouter rhizome, lack of aerial stem, dense pubescence of the basal pedicel and the whole plant. Our phylogenetic analysis, based on ITS sequences, confirms that the new species belongs to V. sect. Diffusae.
Sedum jinglanii, a new species of Crassulaceae from Mount Danxia in Guangdong, China, is described and illustrated. Phylogenetic analysis based on the internal transcribed spacer (ITS) region of nrDNA suggests that the new species belongs to S. sect. Sedum sensu Fu and Ohba (2001) in the “Flora of China”, and is sister to a clade comprising S. alfredi and S. emarginatum with high support values (SH-aLRT = 84, UFBS = 95) but is distantly related to S. baileyi. The new species is morphologically similar to S. alfredi but it can be distinguished from the latter in its opposite leaves (vs. alternate leaves), its usually wider leaves (0.4–1.2 cm vs. 0.2–0.6 cm), its usually shorter petals (3.4–4.5 mm vs. 4–6 mm), its shorter nectar scales (0.4–0.5 mm vs. 0.5–1 mm), its shorter carpels (1.5–2.6 mm vs. 4–5 mm), and its shorter styles (0.6–0.9 mm vs. 1–2 mm). The new species can be easily distinguished from S. emarginatum which both have opposite leaves by its short, erect or ascending rhizome (vs. long and prostrate rhizome in the latter), shorter petals (3.4–4.5 mm vs. 6–8 mm) and shorter carpels (1.5–2.6 mm vs. 4–5 mm). It can also be easily distinguished from S. baileyi by its short, erect or ascending rhizome (vs. long and prostrate rhizome) and its shorter style (0.6–0.9 mm vs. 1–1.5 mm).