This study uncovered the genetic basis of leaf variegation for 35 diverse flowering plants. The underlying loss-of-function plastome mutations in albino sectors include single nucleotide substitutions and insertions/deletions in protein genes mostly related to transcription and photosynthesis. Variegated plants have high ornamental value in horticulture. However, the genetic basis of plant variegation has not been systematically investigated. Here we investigated the genetic basis of variegation for 46 plants by comparing the plastid genomes (plastomes) of green and albino sectors of each plant. Our analyses revealed that 35 plants each had a single plastome mutation in their albino sectors, while the remaining 11 had no plastome mutations, which may be caused by mutations in their nuclear or mitochondrial genomes. These 35 mutations include 12 single nucleotide substitutions, and 17 small (1–10 bp), 3 medium (11–100 bp) and 3 large (> 100 bp) insertions/deletions (indels) in protein genes mostly related to transcription and photosynthesis. All the single nucleotide substitutions cause premature stop codons, 19 of the 20 small and medium indels generate frameshifts and premature stop codons, and all three large indels eliminate multiple genes. The remaining one is a 6-bp deletion occurring in the intron of rps16, which may cause a splicing defect. Dysfunction of these genes due to mutations can explain leaf variegation in the 35 plants. Combining with previous studies, we found that plastome mutations leading to leaf variegation occur predominantly in the coding regions of the LSC and much more common in rpo genes than other genes. Relative to single nucleotide substitutions, indels are much more common. Over half of the detected indels are copy-number variations, suggesting replication slippage is a major mechanism of plastome mutations. Our study deepens the understanding of the genetic basis of plant variegation.

Melastomataceae are a megadiverse, worldwide family, comprising about 173 genera and almost 6000 species distributed mostly in the tropics. Although molecular phylogenetics have clarified major tribal relationships over the past few decades, deeper nodes within the family remain difficult to resolve with only a few number of plastid and nuclear loci, highlighting the need for genomic-scale data including major representatives across the family to resolve these recalcitrant nodes. In this study, we reconstructed a phylogenetic tree for Melastomataceae comprising all tribes and more than 90% of the generic diversity, based on hundreds of loci sampled across nuclear, chloroplast and mitochondrial genomes. This represents the most taxonomically comprehensive phylogenetic study of the family to date, particularly with respect to major lineages of Melastomataceae. We inferred phylogenies for each genome compartment and assessed topological discordance among them. We further evaluated the nuclear gene tree discordance and quantified the relative contribution of incomplete lineage sorting and reticulation. We also reconstructed ancestral chromosome number evolution to identify polyploidization events. We recovered robust phylogenies congruent with previous analyses, but relationships and branch support recovered at deeper nodes varied across genome compartments. Our nuclear genomic dataset resulted in highly supported phylogenetic relationships across the entire tree. Plastid and mitochondrial topologies were mostly concordant, but were highly discordant with nuclear topologies, especially in the backbone relationships of the family. Most nuclear gene tree discordance at deep nodes of Melastomataceae can be attributed to gene tree estimation error and ILS, but reticulation events at deep and shallow levels also play a role. Gene duplication and polyploidization events introduce additional conflict within closely related major clades, highlighting the complex evolutionary radiation of the family.

PREMISE:Advances in new next-generation sequencing (NGS) methods have revolutionized phylogenetics, yet challenges remain in effectively utilizing data from a wide range of sources. A well-resolved and broadly sampled phylogeny for Sonerileae, the second-largest tribe in Melastomataceae, is still lacking, hindering our understanding of its phylogenetic relationships and evolutionary history. METHODS:We combined target enrichment, genome skimming, RNA-Seq, and deep genome skimming (DGS) data to reconstruct the phylogenetic relationships within Sonerileae. We sampled 184 accessions representing 41 of the 47 genera in the tribe, including new sequences obtained with Hyb-Seq and DGS, and publicly available sequences. A newly developed reference comprising 5626 loci was employed to integrate data from different sources. RESULTS:Our analyses produced a well-supported, near-comprehensive phylogeny for the tribe, outperforming previous and current studies that used only target enrichment probe sets as the reference for loci extraction. For the long-unresolved Asian Sonerileae, our phylogeny is comparable to that of a study focused specifically on that group, where a draft genome was required to identify orthologs. CONCLUSIONS:Our analyses demonstrate that using an inclusive reference file enables the integration of genomic data generated with different sequencing strategies. We provide an effective approach for combining heterogeneous data for phylogenomic analysis.

Bredia cordata H. L. Li, J. Arnold Arbor. 25: 24. 1944. Figs 2, 15 A ≡ Bredia esquirolii var. cordata (H. L. Li) C. Chen, Bull. Bot. Res., Harbin 4 (3): 40. 1984. = Phyllagathis fordii var. micrantha C. Chen, Bull. Bot. Res., Harbin 4 (3): 50. 1984, p. p., quoad specim. T. C. Li 4756, F. T. Wang 23533, C. Y. Wu et al. 6307, C. Y. Wu 6325, Z. T. Guan 6154. = Bredia esquirolii auct. non. (H. Lév.) Lauener, Chen in Fl. Reipubl. Popularis Sin. 53 (1): 206; Chen et Renner in Fl. China 13: 375. Type. China • Sichuan: Ya-an, dense forest shade, 686 m, 30 Jul 1939, C. Y. Chiao 1205 [holotype: A! (A 00071982)]. Description. Shrubs 20–50 cm tall, branched. Stems erect, branched, terete, obtusely 4 - sided, densely pubescent with 0.3–1 mm long multiseriate glandular hairs and puberulent with minute uniseriate (spreading or bent) hairs, rarely without multiseriate hairs. Leaves opposite, equal or unequal; petiole 1–8 cm long, pubescent and puberulent as the stem; leaf blade ovate, ovate-elliptic, or oblong-ovate, 2–14 × 1.5–8.2 cm, thin to thick papery, secondary veins 3 on each side of midvein, abaxial surface pale green to purplish, adaxial surface green to dark green, both surfaces puberulent with uniseriate hairs and sparsely strigose with multiseriate hairs or abaxially glabrescent and adaxially sparsely strigose, base cordate, margin serrulate or inconspicuously so with each tooth having a terminal seta, apex acuminate or short acuminate, rarely acute. Inflorescence a terminal cyme, rarely a cymose panicle; peduncle 1–3.5 cm long, indumentum same as the stem, 2–12 - flowered. Flowers bisexual, radial but androecium slightly bilateral, 4 - merous; pedicel 0.7–2 cm long, indumentum same as the stem; hypanthium bell- or funnel-shaped, 4–6 mm long, pubescent with glandular hairs, rarely only puberulent; calyx lobes linear-lanceolate, 3–5 mm long, pubescent with glandular hairs, rarely only puberulent; petals pink to purplish-red, ovate, 6–10 × ca. 6 mm, oblique, abaxially puberulent with minute uniseriate hairs or glabrescent, apex acute; stamens 8 in two whorls, often dimorphic, sometimes isomorphic, the outer whorl of the dimorphic stamens ca. 1.8 cm long, filaments ca. 10 mm long, anthers linear, ca. 7 mm long, curved, connective decurrent, slightly prolonged, the inner whorl of the dimorphic stamens or the isomorphic ca. 1.1 cm long, filaments ca. 6 mm, anthers lanceolate, slightly curved, ca. 5 mm long, forming two ventral lobes and a dorsal tubercule / short spur; ovary half inferior, locules 4, apex with a membranous crown, crown margin denticulate and ciliate with glandular hairs; style ca. 8–12 mm long, basally puberulent. Capsule ca. 6–9 × 5–7 mm, funnel-shaped, with enlarged apical crown; placentation axial, placentas non-thready. Seeds numerous, cuneate. Phenology. Flowering June to August, fruiting September to October. Notes. Bredia cordata can be readily distinguished from B. esquirolii by the leaf blade having 3 secondary veins (vs. 2) on each side of midvein, smooth petal margin (vs. undulate), linear-lanceolate calyx lobes (vs. broadly ovate to semiorbicular), and often dimorphic stamens (vs. isomorphic). It occurs in Sichuan, northern Guizhou, southern Chongqing, and northeastern Yunnan. Most populations have dimorphic stamens. However, both isomorphic and dimorphic morphs have been recorded in different populations and even within the same population in Sichuan and Chongqing, a rare occurrence in Melastomataceae. Additional specimen examined. China. Chongqing Municipality: • Beibei District, S. J. Wang 1231 (NAS), Sichuan-Guizhou Exped. 260 (PE), 759 (PE); • Jiangjin District, Z. Y. Liu 183157 (PE); • Banan District, Z. Y. Liu 180119 (PE). Guizhou Province: • Chishui County, M. C. Wang 520381150502008 LY (GZTM), C. K. Liu CS 9174 (MUCH); • Xishui County, Bijie Exped. 1695 (HGAS, KUN, PE). Sichuan Province: • Emeishan County, Z. W. Yao 2558 (KUN), T. C. Lee 4756 (KUN), F. T. Wang 23533 (WUK); • Gulin County, PE-Gulin Exped. 617 (PE); • Hongya County, Z. W. Wang 477 (CDBI), W. K. Bao 1241 (CDBI); • Jiajiang County, Y. Z. Tang et al. s. n. (CDBI); • Leshan County, Z. T. Guan 6154 (IBSC, KUN, PE); • Leibo County, Anonymous 574 (PE); • Pingshan County, Sichuan Econ. Pl. Exped. Yibin Division 753 (KUN); • Songpan County, W. P. Fang 6024 (PE); • Tianquan County, W. G. Hu and Z. He 11827 (PE); • Xuyong County, W. B. Ju and H. N. Deng HGX 13070 (CDBI). Yunnan Province: • Suijiang County, B. X. Sun et al. 310 (PE), 534 (KUN); • Yanjin County, NE Yunnan Exped. 923 (KUN).

Bredia esquirolii (H. Lév.) Lauener, Notes Roy. Bot. Gard. Edinburgh 31 (3): 398. 1972. Figs 3, 15 B ≡ Barthea esquirolii H. Lév., Repert. Spec. Nov. Regni Veg. 11: 494. 1913 (Basionym). Type: China. Guizhou: Tchai-choui-ho, Jul 1909, Esquirol 1581 [holotype: E! (E 00090793)]. = Barthea cavaleriei H. Lév., Repert. Spec. Nov. Regni Veg. 8: 61. 1910, p. p., excl. specim. Esquirol 215. Type: China. Guizhou: near Mou-you-sé, J. Cavalerie 1552 [lectotype, designated by Diels (1932): E! (E 00090789)]. ≡ Fordiophyton cavaleriei (H. Lév.) Guillaumin, Bull. Soc. Bot. France 60: 275. 1913, p. p., excl. pl. Yunnan. ≡ Bredia cavaleriei (H. Lév.) Diels, Bot. Jahrb. Syst. 65 (2–3): 110. 1932, hom. illeg., non H. Lév. & Vaniot (1906). ≡ Bredia longiradiosa C. Chen, Fl. Yunnan. 2: 105, 1979, nom. inval., p. p., quoad pl. Guizhou. Type: Based on Barthea cavaleriei H. Lév. ≡ Bredia longiradiosa (C. Chen) C. Chen ex Govaerts, World Checkl. Seed Pl. 2 (1–2): 13. 1996, p. p., quoad typum. ≡ Phyllagathis longiradiosa C. Chen, Bull. Bot. Res., Harbin 4 (3): 51. 1984, p. p., quoad pl. Guizhou. syn. nov. = Phyllagathis longearistata C. Chen, Bull. Bot. Res., Harbin 4 (3): 52. 1984. Type: China. Guangxi: Hechi, prope rivulos in convallibus montanis, 19 May 1928, L. H. Chun 91861 [holotype: IBK! (IBK 00190677); isotype: IBK! (IBK 00190678)]. ≡ Bredia longearistata (C. Chen) R. Zhou & Ying Liu, PhytoKeys 127: 145. 2019. syn. nov. = Phyllagathis latisepala C. Chen, Bull. Bot. Res., Harbin 4 (3): 53. 1984. Type: China. Hubei: Hefeng, ad pedes montis calcareo, 18 Sept 1958, H. J. Li 6451 [holotype: IBSC! (IBSC 0003996); isotypes: PE! (PE 00025692), HIB (HIB 0060155)]. ≡ Bredia latisepala (C. Chen) R. Zhou & Ying Liu, PhytoKeys 127: 145. 2019. syn. nov. Description. Herbs or shrubs, 20–40 cm tall. Stems prostrate in lower parts and ascending in the upper parts, terete, sparsely villous with spreading multiseriate hairs and puberulent with bent uniseriate hairs when young, sometimes glabrescent. Leaves opposite; petiole 2–8 cm long, indumentum same as branchlets; leaf blade ovate to oblong ovate, 3.5–9 × 1.5–6 cm, submembranous, secondary veins 2 on each side of midvein, adaxial surface green to purplish dark green, abaxial surface pale green to purplish-red, with bent uniseriate hairs and sparse multiseriate setas when young on both sides, with minute yellowish glandular hairs on the abaxial surface, base subcordate to obtuse, margin inconspicuously denticulate with each tooth having a terminal seta, apex acute or short acuminate. Inflorescence terminal, umbellate, rarely cymose paniculate, 3–11 - flowered; peduncle 1.5–5 cm long. Flowers bisexual, radial but androecium slightly bilateral, 4 - merous; pedicel 1–2 cm long; hypanthium yellowish-green, funnel-shaped, ca. 5 mm long, villous with multiseriate hairs with inflate bases or only puberulent; calyx lobes 4, broadly ovate to semiorbicular; petals 4, pink to purplish, ovate, ca. 6 × 7 mm, petal margin undulate, apex oblique; stamens 8 in two whorls, isomorphic, equal in length, filaments ca. 5 mm long, bent with the anthers to one side of the flower, anthers lanceolate, slightly curved, ca. 7 mm long, white, connectives forming 2 ventral lobes and a dorsal short spur, white or light purple; ovary ca. 3 mm long (crown excluded), half inferior, locules 4, apex with membranous crown, crown margin denticulate; style ca. 1 cm long, basally puberulous. Capsule funnel-shaped, with enlarged apical crown; placentation axial, placentas non-thready. Seeds numerous, cuneate. Phenology. Flowering April to July, fruiting May to August. Distribution. Bredia esquirolii is known from Guangxi, southern Guizhou, Hunan, Chongqing, and Hubei, China, growing in karst or non-karst habitats in forest or along forest margin at 250–1,200 m. Additional specimen examined. China. Chongqing Municipality: • Wulun County, Z. Y. Liu 181907 (PE). Guangxi Province: • Bama County, W. B. Xu and Y. Liu 09344 (IBK); • Debao County, Debao Exped. 451024170219012 LY (IBK); • Fengshan County, Y. D. Peng et al. 451223121026092 LY (GXMG); • Hechi City, Mulun Exped. M 0220 (PE), L. H. Chun 92034 (IBK), Huanjiang Exped. 451226130314019 LY (GXMG, IBK), 451226130723003 LY (GXMG, IBK), Hechi Exped. 4-4 - 465 (GXMI), W. B. Xu and B. Pan 09527 (IBK), W. B. Xu 091711 (IBK), Y. Liu 496 (SYS), 498 (SYS), 859 (SYS); • Lipu County, Lipu Exped. 450331180823035 LY (IBK), 450331170710033 LY (IBK), 450331180520007 LY (IBK); • Liujiang County, Liujiang Exped. 450221200728017 LY (IBK), 450221200730042 LY (IBK), 450221200731016 LY (IBK), 450221190718010 LY (IBK), 450221190403042 LY (IBK), 450221180810019 LY (IBK); • Nandan County, Nandan Exped. 4-5 - 1005 (GXMI), Nandan Exped. 451221180526064 LY (GXMG), 451221180525032 LY (GXMG), 451221190705036 LY (GXMG); Tian’e County, Beijing Team 891333 (PE), 891340 (PE), D. Y. Liu 58480 (GXMI). Guizhou Province: • Without precise location, Cavalerie 3638 (P), Cavalerie 2015 (P), Esquirol 3148 (P); • Libo County, Q. R. Liu 2018080412 (BNU), Y. Liu 744 (SYS), 875 (SYS); • Xingyi County, Cavalerie 1917 (P), Esquirol 4571 (P), C. Y. Deng 2021051961 (XIN); • Wangmo County, Y. Liu 912 (SYS). Hunan Province: • Baojing County, D. G. Zhang 0905626 (JIU), X. J. Su and H. B. Liu 433125 D 00031114003 (JIU); • Sangzhi County, Sangzhi Forestry Institute 1150 (KUN), Anonymous 614 (PE), Beijing Team 4043 (PE), 2931 (PE), 2999 (PE), Y. Liu 557 (SYS); • Shimen County, Hupingshan Exped. 0880 (PE).

The Cyphotheca-Plagiopetalum-Sporoxeia clade (Sonerileae, Melastomataceae) comprises Cyphotheca Diels, Plagiopetalum Rehder, Sporoxeia W.W.Sm., and some species of the highly polyphyletic Phyllagathis Blume, as well as some undescribed species, which requires taxonomic revision at the generic level. In this study, we expanded taxon sampling of the CPS clade and reconstructed phylogenetic relationships using genomic SNPs and whole plastomes assembled from genome resequencing data. We recognized six subclades in the CPS clade and observed strong cytonuclear incongruences within and among subclades. Gene tree simulation and Patterson's D-statistic indicated that the conflicting phylogenetic signals were mainly caused by incomplete lineage sorting and hybridization/introgression. Molecular and morphological divergence among species of the CPS clade were evaluated using principal component analysis. Genomic SNP data clearly separated the six subclades, whereas the boundaries of some subclades were obscure in the plots of morphological data. Through reconstruction of morphological characteristics, we found a high level of homoplasy for some characters but also identified potential synapomorphies for the lineages. Based on the results, a revised generic classification is proposed for the CPS clade. Specifically, we expand Cyphotheca, Plagiopetalum, and Sporoxeia to include additional species, and establish three new genera, namely Chiehchenii, Neophyllagathis, and Sporocyphoxeia. A description and a list of species are provided for each of the six genera. Four new species are described.

Reaumuria songarica is a key dominant species in the desert regions of northern China. The selection of appropriate seed source and the determination of optimal seed harvesting times are critical for the development and utilization of its germplasm resources. In this study, nine R. songarica habitats with varying precipitation levels were identified in the HeHuang Valley. We determined the optimal seed harvesting period and evaluated seed traits, germination characteristics, and initial seedling growth at this optimal period harvest time. The results indicated that the optimal harvesting window for R. songarica seeds is between 60 and 100 days after flowering, depending on the precipitation of the seed source area. Species origin accounted for the largest variation in seed germination characteristics and seedling growth, with the highest coefficient of variation observed in the vitality index (28.44%) and the lowest in seed viability (3.78%). In the standard germination test, seed germination was primarily influenced by 1000-seed weight and seed viability, while seedling growth was mainly affected by seed electrical conductivity. Seed drought germination resistance was most influenced by seed biofilm integrity and seed size. In conclusion, high-quality, drought-tolerant R. songarica germplasm can be obtained by selecting drought-prone seed source areas in the HeHuang Valley and harvesting seeds between 90 and 100 days after flowering. These findings underscore the critical role of precipitation at the seed source in shaping seed and seedling traits, providing valuable guidance for the future development and utilization of R. songarica germplasm resources.

Pternopetalum wulingense (Apiaceae) is described as a new species from the Wuling Mountains in Guizhou Province and Chongqing Municipality, China. Both phylogenetic analyses and diagnostic morphological traits support its placement within Pternopetalum and confirm its distinction from close relatives. It closely resembles P. trichomanifolium in having finely dissected 3–4-pinnate basal leaves and a preference for moist habitats, but differs in having a rhombic leaf blade outline, ultimate segments of uniform width and oblong-ovoid fruits with both mericarps fully developed.

Cassava (Manihot esculenta Crantz) is a crucial staple food crop, yet our understanding of its chloroplast (cp.) genome has been limited due to the extensive diversity among cultivars. This lack of clarity has significantly impeded our comprehension of cp. genome evolution and genetic relationships within cassava germplasm. A total of 385 complete chloroplast (cp.) genomes of cassava cultivars were newly assembled. Comprehensive comparative analysis and phylogenetic trees were conducted. The cp. genomes varied in size from 160,702 to 161,564 bp, with GC content ranging from 35.87 to 35.97

A recent phylogenomic analysis has unveiled the first highly resolved phylogeny for the genus Bredia , clarifying long-standing uncertainties in species boundaries among taxonomically debated groups. Based on these findings, we propose a taxonomic revision encompassing the following updates: (1) B. latisepala , B. longearistata , and B. longiradiosa are synonymized under B. esquirolii ; (2) B. dulanica C.L.Yeh, S.W.Chung & T.C.Hsu is incorporated within B. hirsuta ; (3) two new combinations are established, alongside the formal recognition of three new species and one new variety (Suppl. material 1); (4) Bredia bullata S.Jin Zeng & N.H.Xia is regarded as a later homonym and therefore illegitimate name for B. bullata J.H.Dai & Ying Liu. Morphological descriptions, color plates, and updated distribution maps are provided for relevant taxa, supplemented by a key to all recognized Bredia species.

The gene GAD1 encodes a glutamate decarboxylase, which is a rate-limiting enzyme for the biosynthesis of endogenous gamma-aminobutyrate acid (GABA), but a potential role of GAD1 in regulating cadmium (Cd) tolerance needs to be further elucidated in plants. The objective of this study was to investigate Cd tolerance of creeping bentgrass (Agrostis stolonifera) and transgenic yeast (Saccharomyces cerevisiae) or Arabidopsis thaliana overexpressing AsGAD1. The Cd-tolerant creeping bentgrass cultivar LOFTSL-93 accumulated more endogenous GABA in relation to a significant upregulation of AsGAD1 in leaf and root than the Cd-sensitive W66569 in response to Cd stress. The overexpression of AsGAD1 significantly enhanced Cd tolerance of yeast or A. thaliana associated with improved endogenous GABA content, low oxidative damage, and high cell membrane stability and photochemical efficiency. Compared with wild type, AsGAD1-overexpressing plants or the atgad1 mutant maintained significantly lower or higher Cd content in leaf and root by down-regulating or up-regulating transcript levels of AtNRAMP1/2/3/4/5 and AtZIP1/2, respectively. Moreover, overexpression of AsGAD1 significantly up-regulated transcript levels of AtHMA1/3, contributing to better Cd compartmentalization from chloroplast into cytoplasm and then into vacuoles. AsGAD1 overexpression also induced expressions of AsMT1A/1B/1C/2/3, AsGSH1/2, and AsPCS1/2, indicating better capacity of Cd chelation in cytosol and vacuoles for Cd detoxification. Hence, AsGAD1-regulated detoxification mechanism of Cd could be related to Cd uptake, transport, and chelation. In addition, lipid contents (PC, PG, and DGDG) and the DGDG/MGDG and PC/PG ratios were improved by the AsGAD1 overexpression, which favors membrane stability and functionality under Cd stress. These findings provide new insight into the regulatory role of GAD1 in Cd tolerance in plants.

Sinoseneciotongziensis R.B.Zhang, Tan Deng & Ying Liu (Asteraceae), a new species from Tongzi County in northern Guizhou, China, is described and illustrated. It closely resembles S.changii in the subscapigerous habit, ovate-oblong and pinnately veined leaf lamina, and simple to compound terminal corymbs, yet differs markedly by the texture of leaf lamina (membranous vs. papery), the number of lateral veins (8-10 vs. 10-18), and the indumentum on the stems, leaves, and inflorescences (pubescent with 2-5 mm long, uniseriate, spreading hairs vs. sparsely white arachnoid to densely white tomentose). Phylogenetic analysis indicates that S.tongziensis is related to S.bodinieri, S.nanchuanicus, S.confervifer, and S.globigervar.adenophyllus.

Plastome variation, including single spontaneous nucleotide substitutions and single insertions/deletions, is the major source of leaf variegation in plants. Additionally, one recent study has showed that a simple plastome structural variation, which is induced by one pair of small inverted repeats, can also result in leaf variegation. Here we show a complex plastome structural variation caused by intermolecular and intramolecular recombination across three pairs of small inverted repeats accounts for leaf variegation in a widely cultivated shrub Heptapleurum ellipticum (Araliaceae). This plastome structural variation contains two deletions and two duplications, resulting in dramatic expansion of IRs, substantial contraction of LSC and loss of 11 genes that essential for photosynthesis. Plastome heteroplasmy was detected in both green and albino sectors of variegated leaves. Relative to green sectors, albino sectors in the variegated leaves exhibit significantly reduced expression for the 11 genes lost in the mutated plastome as well as 26 other genes, but significantly increased expression for one gene related to translation apparatus. Optical and transmission electron microscopy observations showed that mesophyll cells of albino sectors possess plastids lacking grana lamellae, which likely carry the mutated plastome and contribute to albinism. In both sectors, the first layer of spongy mesophyll cells beneath the lower epidermis contains normal chloroplasts, suggesting periclinal division of the lower epidermis during development. Our study demonstrates that multiple small repeats can collectively mediate intra- and inter-molecular recombination in plastome and offers a new mechanism accounting for leaf variegation in plants.

Bredia micrantha (C. Chen) J. H. Dai & Ying Liu, comb. et stat. nov. Figs 12, 15 C ≡ Phyllagathis fordii var. micrantha C. Chen, Bull. Bot. Res., Harbin 4 (3): 50. 1984 (Basionym), p. p., quoad typum. Type: China. Guizhou: Dushan, in convallibus montanis, 600 m, 22 Aug 1930, Y. Tsiang 6563 [holotype: IBSC! (IBSC 0003995); isotypes: NAS! (NAS 00052126), PE! (PE 00782806, PE 00782810)]. ≡ Bredia fordii var. micrantha (C. Chen) R. Zhou & Ying Liu, PhytoKeys 127: 144. 2019. Diagnosis. Similar to B. fordii and B. esquirolii in posture and leaf shape, but differs in the stems sparsely pubescent with 1.5–2 mm long, spreading, multiseriate hairs (vs. the former with dense, 2–4 mm long hairs, and the latter with 0.3–1 mm long hairs), young inflorescence bending downwards (vs. erect), slightly curved anthers (vs. geniculate), and cream connectives (vs. yellow at least in the inner stamens). Resembles B. jiuwanshanensis in the stems with dense, spreading, 0.3 mm long uniseriate hairs, bending young inflorescence, and isomorphic stamens, but differs markedly in posture (few branched vs. multi-branched), larger (3.5–13 × 1.7–6.3 cm vs. 1.5–7 × 0.7–3.8 cm), submembranous to thin papery (vs. thick papery), more or less ovate leaf blade (vs. elliptic to narrowly elliptic) with cordate base (vs. obtuse or rounded), and acuminate apex (vs. acute), and anthers and connectives of cream color (vs. purple anthers and yellow connectives at anther base). Description. Shrubs, to 60 cm tall. Stems erect or ascending, few-branched, terete; branchlets densely pubescent with 0.3 mm long uniseriate hairs and sparsely pubescent with 1.5–2 mm long, spreading, multiseriate hairs. Leaves opposite, equal or unequal; petiole 1.8–6 cm long, densely pubescent with spreading, multiseriate and uniseriate hairs; leaf blade ovate-cordate to ovate-lanceolate, rarely obovate, 3.5–13 × 1.7–6.3 cm, submembranous to thin papery, secondary veins 3 on each side of midvein, adaxial surface green, pubescent with bent uniseriate hairs, denser along the veins, abaxial surface pale green or ± purplish, pubescent with spreading, uniseriate and multiseriate hairs, base shallowly cordate, margin ciliate and inconspicuously serrulate with each tooth having a terminal seta, apex acuminate, rarely acute. Inflorescence bending downwards when young, 2–10 - flowered; peduncle 1.3–3.3 cm long, densely pubescent. Flowers bisexual, radial but androecium slightly bilateral, 4 - merous, pedicles, hypanthium and calyx lobes densely pubescent with 0.5–1 mm long hairs; pedicel 0.8–1.5 cm long; hypanthium yellowish-green, funnel-shaped, 5 × 3–4 mm; calyx lobes 4, linear, 4–5 × 0.5 mm; petals 4, purplish-red, ovate, ca. 8 × 7 mm, puberulent on the abaxial surface with uniseriate hairs, apex oblique; stamens 8 in two whorls, isomorphic, subequal in length with the outer whorl slightly longer than the inner one, filaments ca. 6–7 mm long, bent with the anthers to one side of the flower, anthers lanceolate, slightly curved, 6–7 mm long, cream, connective forming 2 ventral lobes and a dorsal tubercle of the same color; ovary ca. 4 mm long, 2 / 3 as long as the hypanthium (crown excluded), half inferior, locules 4, apex with membranous crown, crown margin ciliate with dark red glandular hairs; style ca. 1.3 cm long, basally puberulent. Capsule ca. 6 × 5 mm, funnel-shaped, with enlarged apical crown; placentation axial, placentas non-thready. Seeds numerous, cuneate. Phenology. Flowering July to August, fruiting August to September. Distribution. Bredia micrantha is currently only known from Dushan County, Guizhou, China, occurring among rocks near stream or on moist rock in forests. Additional specimen examined. China. Guizhou Province: • Dushan County, Cha-he to Li-zi-chong, on shaded and moist rocks or rock cliff in forests, 1,000 m, 16 Aug 2019, J. H. Dai and Y. Liu 745 (A, PE, SYS).

Bredia pingshanensis J. H. Dai & Ying Liu sp. nov. Figs 13, 14, 15 D Type. China • Sichuan: Pingshan County, Lao-jun-shan Nature Reserve, Xin-tian-zui to Er-nian-ping, on shaded and moist steep slope along the road, 1,263 m, 30 Aug 2019, J. H. Dai and Y. Liu 757 [holotype: PE!; isotypes: A!, SYS!]. Diagnosis. Somewhat resembles B. cordata in ovate leaf blade of similar size, glandular pubescent hypanthium, and ovate-triangular calyx lobes, but differs in the stems and leaves inconspicuously puberulent with bent uniseriate hairs (vs. usually with dense spreading hairs), leaves usually unequal (vs. equal to subequal), leaf base very shallowly cordate or rounded (vs. cordate), white (vs. pink) petals with the abaxial surface reddish glandular pubescent along the midvein (vs. glabrous to inconspicuously puberulent, colorless), deep purple anthers (vs. white to light purple), and purplish-red connectives (vs. yellow in the inner stamens). Description. Shrublets to 35 cm tall. Stems erect or ascending, few-branched, terete; branchlets with bending uniseriate hairs and very sparse ca. 0.3 mm long multiseriate setas. Leaves opposite, often unequal; petiole 0.8–8.2 cm long, indumentum same as branchlets but with denser seta; leaf blade ovate or ovate-elliptic, larger ones 4.5–12.3 × 2.8–7.5 cm, smaller ones 2.2–7 × 1.2–5 cm, membranous, secondary veins 2 or 3 on each side of midvein, adaxial surface green, with bent uniseriate hairs and very sparse seta, abaxial surface pale green, pubescent with bent uniseriate hairs, densely so along veins, base shallowly cordate to rounded, sometimes oblique, margin serrulate with each tooth having a terminal seta, apex short acuminate. Inflorescence terminal, cymose, or cymose paniculate, 3–12 - flowered; peduncle 0.8–2.8 cm long, puberulent as branchlets. Flowers bisexual, radial but androecium bilateral, 4 - merous, pedicles, hypanthium and calyx lobes densely pubescent with bent uniseriate hairs and 0.5–1 mm long multiseriate glandular hairs; pedicel 0.4–1 cm long; hypanthium purplish-red, funnel-shaped, 5 × 3–4 mm; calyx lobes 4, ovate-triangular, 3–2 × 1 mm; petals 4, white with pink apex, ovate, ca. 7 × 5.5 mm, puberulent along midvein on the abaxial surface with red glandular hairs, apex slightly oblique; stamens 8 in two whorls, dimorphic, unequal in length, with the outer whorl much longer than the inner one, longer stamens ca. 16 mm long, filaments ca. 9 mm long, anthers lanceolate, curved, ca. 7 mm long, purple, connectives decurrent, purplish-red, forming 2 ventral lobes, shorter stamens ca. 9 mm long, filaments ca. 5 mm long, anthers lanceolate, slightly curved, ca. 4 mm, deep purple, connectives purplish-red, forming 2 ventral lobes and a dorsal tubercle; ovary ca. 4 mm long, 2 / 3 as long as the hypanthium (crown excluded), half inferior, locules 4, apex with membranous crown, crown margin ciliate with red glandular hairs; style ca. 1.2 cm long, basally inconspicuously puberulous. Capsule ca. 6 × 5 mm, funnel-shaped, with enlarged apical crown; placentation axial, placentas non-thready. Seeds numerous, cuneate. Phenology. Flowering August, fruiting September to October. Etymology. The specific epithet refers to the type locality of the new species, Pingshan County. Distribution. Bredia pingshanensis is only known from Lao-jun-shan Nature Reserve in Pingshan County, Sichuan, China, occurring on shaded and moist steep slopes along the road at forest margin.

Sinosenecio tongziensis R.B.Zhang, Tan Deng & Ying Liu (Asteraceae), a new species from Tongzi County in northern Guizhou, China, is described and illustrated. It closely resembles S. changii in the subscapigerous habit, ovate-oblong and pinnately veined leaf lamina, and simple to compound terminal corymbs, yet differs markedly by the texture of leaf lamina (membranous vs. papery), the number of lateral veins (8–10 vs. 10–18), and the indumentum on the stems, leaves, and inflorescences (pubescent with 2–5 mm long, uniseriate, spreading hairs vs. sparsely white arachnoid to densely white tomentose). Phylogenetic analysis indicates that S. tongziensis is related to S. bodinieri , S. nanchuanicus , S. confervifer , and S. globiger var. adenophyllus.

Bredia jiuwanshanensis J. H. Dai & Ying Liu sp. nov. Figs 8, 9, 15 C = Phyllagathis fordii var. micrantha C. Chen, Bull. Bot. Res., Harbin 4 (3): 50. 1984, p. p., quoad specim. S. H. Chun 15828. Type. China • Guangxi: Da-miao-shan County (now Rongshui County), Jiu-wan-shan, Shuang-he-gou, 750–1,200 m, 26 Jul 1958, S. H. Chun 15828 [holotype: IBK! (IBK 00127554); isotypes: HITBC! (HITBC 011254), IBSC! (IBSC 0223746), KUN! (KUN 0156146), PE! (PE 00782743)]. Diagnosis. Most closely resembles B. micrantha in the dense, spreading, uniseriate hairs on the stems, bending young inflorescence, and isomorphic stamens, but differs in posture (multi-branched vs. few branched), smaller (1.5–7 × 0.7–3.8 cm vs. 3.5–13 × 1.7–6.3 cm), thick papery (vs. submembranous to thin papery), elliptic to narrowly elliptic leaf blade (vs. more or less ovate) with obtuse or rounded base (vs. cordate), and acute apex (vs. acuminate), and purple anthers and yellow connectives at anther base (vs. both cream). Description. Shrubs to 20 cm tall. Stems prostrate in lower parts and ascending / erect in upper parts, many-branched, terete; branchlets densely pubescent with 0.5 mm long, spreading, uniseriate hairs and multiseriate glandular hairs. Leaves opposite, equal to unequal; petiole 0.4–2.2 cm long, densely pubescent as branchlets; leaf blade elliptic, oblong-elliptic, or narrowly elliptic, 1.5–7 × 0.7–3.8 cm, thick papery, secondary veins 3 on each side of midvein, adaxial surface green to purplish dark green, puberulent with bent uniseriate hairs and ca. 0.2 mm long multiseriate setas, abaxial surface purplish-red, pubescent as branchlets, densely so along veins, base rounded, rarely truncate, margin ciliate and inconspicuously serrulate with each tooth having a terminal seta, apex acute. Inflorescence a terminal cyme, bending downwards when young, 1–3 - flowered; peduncle 0.5–1.5 cm long, densely pubescent as branchlets. Flowers bisexual, radial but androecium slightly bilateral, 4 - merous, pedicle, hypanthium and calyx lobes densely pubescent with 0.3–1 mm long hairs; pedicel 0.5–1.2 cm long; hypanthium yellowish-green, funnel-shaped, 5–6 × 3–4 mm; calyx lobes 4, narrowly triangular, 2–3 × 0.5 mm; petals 4, purplish-red, ovate, ca. 9 × 7 mm, puberulent with uniseriate hairs at the margin and along midvein on the abaxial surface, apex oblique, short acuminate; stamens 8 in two whorls, isomorphic, equal in length, filaments ca. 7 mm long, bent with the anthers to one side of the flower, anthers lanceolate, slightly curved, ca. 6 mm long, purplish-pink, connective forming 2 yellowish cream ventral lobes and a dorsal short spur of the same color; ovary ca. 4 mm long, 2 / 3 as long as the hypanthium (crown excluded), half inferior, locules 4, apex with membranous crown, crown margin ciliate with red glandular hairs; style ca. 1.4 cm long, basally puberulous. Capsule ca. 7 × 6 mm, funnel-shaped, with enlarged apical crown; placentation axial, placentas non-thready. Seeds numerous, cuneate. Phenology. Flowering late July to August, fruiting September. Etymology. The specific epithet refers to the type locality of the new species, Jiu-wan-shan Nature Reserve. Distribution. Bredia jiuwanshanensis is only known from Jiu-wan-shan Nature Reserve in Rongshui County, northern Guangxi, China, occupying moist soil slopes in forests or along forest margin. Additional specimen examined. China. Guangxi Province: • Rongshui County, Jiu-wan-shan Nature Reserve, Yang-mei-ao, Jiu-ren station, Bai-yan-shan, along forest margin and on soil slopes in forests, 1,400 m, 24 Jul 2021, J. H. Dai and Y. Liu 880 (A, PE, SYS).

Bredia hirsuta Blume, Mus. Bot. 1 (2): 24. f. IV. 1849. Fig. 7 = Bredia dulanica C. L. Yeh, S. W. Chung & T. C. Hsu, Edinburgh J. Bot. 65 (3): 395 (398, fig. 2; 402, fig. 4 A, B). 2008. syn. nov. Type: China. Taiwan Province: Taitung, Mt. Dulan, on the ridge of a mountain, 1000–1200 m, 14 Oct 2007, S. W. Chung, T. C. Hsu & C. R. Yeh 16 [holotype: TAIF! (TAIF 348619); isotypes: TAIF! (TAIF 348620, TAIF 348621, TAIF 348622)]. Type. Japan • K. Ito s. n. [lectotype designated by Zhou et al. (2019 c): L! (L 0170980)]. Notes. Bredia dulanica was described based on specimens collected from Mt. Dulan, southeastern Taiwan (Yeh et al. 2008). Yeh et al. (2008) suggested that it is closely related to B. hirsuta, a species found in Taiwan and the Ryukyu Islands, but can be distinguished by the rod-shaped ventral appendages and the calyx lobes with red strigose hairs abaxially. However, the accession from Mt. Dulan (LY 565) is deeply nested within B. hirsuta in the species tree based on single-copy orthologs (Fig. 1). A comparison of living plants of B. dulanica and B. hirsuta from Taiwan and Okinawa revealed no obvious difference in stamen morphology and hairiness (Fig. 7). Based on the above findings, we consider B. dulanica to be a synonym of B. hirsuta. Additional specimen examined. China. Taiwan Province: • Taidong County, S. M. Liu et al. 507 (PE), S. W. Chung 8254 (TAIF), 8249 (TAIF).

Bredia hirsuta Blume, Mus. Bot. 1 (2): 24. f. IV. 1849. Fig. 7 = Bredia dulanica C. L. Yeh, S. W. Chung & T. C. Hsu, Edinburgh J. Bot. 65 (3): 395 (398, fig. 2; 402, fig. 4 A, B). 2008. syn. nov. Type: China. Taiwan Province: Taitung, Mt. Dulan, on the ridge of a mountain, 1000–1200 m, 14 Oct 2007, S. W. Chung, T. C. Hsu & C. R. Yeh 16 [holotype: TAIF! (TAIF 348619); isotypes: TAIF! (TAIF 348620, TAIF 348621, TAIF 348622)]. Type. Japan • K. Ito s. n. [lectotype designated by Zhou et al. (2019 c): L! (L 0170980)]. Notes. Bredia dulanica was described based on specimens collected from Mt. Dulan, southeastern Taiwan (Yeh et al. 2008). Yeh et al. (2008) suggested that it is closely related to B. hirsuta, a species found in Taiwan and the Ryukyu Islands, but can be distinguished by the rod-shaped ventral appendages and the calyx lobes with red strigose hairs abaxially. However, the accession from Mt. Dulan (LY 565) is deeply nested within B. hirsuta in the species tree based on single-copy orthologs (Fig. 1). A comparison of living plants of B. dulanica and B. hirsuta from Taiwan and Okinawa revealed no obvious difference in stamen morphology and hairiness (Fig. 7). Based on the above findings, we consider B. dulanica to be a synonym of B. hirsuta. Additional specimen examined. China. Taiwan Province: • Taidong County, S. M. Liu et al. 507 (PE), S. W. Chung 8254 (TAIF), 8249 (TAIF).

Despite only limited sampling, the holoparasitic plant family Balanophoraceae harbors extreme mito-genome diversity and also has exceptionally divergent plastomes. We therefore sequenced the mitochondrial, plastid, and nuclear genomes of Balanophora yakushimensis and its transcriptome. At 1.1 Mb, the B. yakushimensis mitogenome is one of the largest known mitogenomes. Driving this expansion and generating the most repeat-rich mitogenome in land plants are many large (up to 200 kb) duplications and a massive proliferation of short, AT-rich repeated sequences. The repeat proliferation, in conjunction with a highly elevated and unusually AT-biased mutation rate, has produced what is by far the most AT-rich land-plant mito-genome. These invasive repeats also created giant introns, unprecedented in size for organelles, and greatly expanded all rDNA exons. We discovered a record-low, for all genomes, transition/transversion ratio (0.12) in B. yakushimensis mtDNA and documented a 26-fold range in this ratio across angiosperm mitogenomes. The B. yakushimensis nuclear genome has lost exceptionally many genes that function in organellar DNA recombination, repair, and replication (RRR). We discuss ways in which these losses—and other genetic alterations as well as non-genetic ones—may or may not be related to the unusual features of both its mitochondrial and plastid genomes. The mitogenome of B. yakushimensis possesses many exceptional, indeed record-setting properties. The unprecedented loss of nuclear genes for organellar DNA RRR may explain some of these unusual features. These findings expand the boundaries of mitogenome deviancy and raise outstanding questions about the forces driving such extravagantly diversifying evolution.