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The star fruit is a perennial woody fruit tree, which can blossom and bear fruit many times a year. The time and quantity of flowering are the key indicators of its economic value. However, the flowering molecular mechanism of star fruit is still unknown. This study provides a genome-wide analysis of the key flowering genes of star fruit. Based on a previous morphological study of flower bud differentiation, the reproductive buds, vegetative buds and mature leaves of star fruit were sampled for transcriptome analysis. The results showed that the expression of GI, COL4, COL5, FT, FCA, FVE, PIF4, LFY, SVP-like, AP1 and FUL was correlated with floral induction and transition. The expression of TFL1, SVP-like genes (Yangtao2015203 and Yangtao2021074) was correlated with the inhibition of floral transition. Thus, we proposed a putative network of flower blooming in star fruit. This study provides useful information for investigating the genetic mechanism of flowering in star fruit and other perennial woody fruit trees.

Cymbidium, which includes approximately 80 species, is one of the most ornamental and cultivated orchid genera. However, a lack of markers and sparse sampling have posed great challenges to resolving the phylogenetic relationships within the genus. In the present study, we reconstructed the phylogenetic relationships by utilizing one nuclear DNA (nrITS) and seven plastid genes (rbcL, trnS, trnG, matK, trnL, psbA, and atpI) from 70 species (varieties) in Cymbidium. We also examined the occurrence of phylogenetic conflict between nuclear (nrITS) and plastid loci and investigated how phylogenetic conflict bears on taxonomic classification within the genus. We found that phylogenetic conflict and low support values may be explained by hybridization and a lack of informative characteristics. Our results do not support previous classification of the subgenera and sections within Cymbidium. Discordance between gene trees and network analysis indicate that reticulate evolution occurred in the genus Cymbidium. Overall, our study indicates that Cymbidium has undergone a complex evolution., Highlights • A comprehensive understanding of Cymbidium phylogeny. • Reticulate evolution occurred in the genus Cymbidium. • Cymbidium has a complex evolution.

Orchids are horticultural plants with significant ornamental and economic value. Increasing market circulation and rising trade in orchids is forcing breeders to develop varieties with unique characteristics, including flower color, morphology, and resistance using a range of approaches, including traditional and molecular breeding. Advances in high-throughput technologies have generated extensive data sets with greater sequencing depths and broader coverage, providing the potential for discovering new genes/pathways that give rise to key traits. Several attempts have been made to use emerging molecular and omics methods to accelerate the breeding process in certain of the commercially valuable orchids. This review consolidates current approaches and achievements in orchid breeding and discusses their future applications for improving the resistance, ornamental, and other valuable characteristics of these plants.

The wood sorrel family, Oxalidaceae, is mainly composed of annual or perennial herbs, a few shrubs, and trees distributed from temperate to tropical zones. Members of Oxalidaceae are of high medicinal, ornamental, and economic value. Despite the rich diversity and value of Oxalidaceae, few molecular markers or plastomes are available for phylogenetic analysis of the family. Here, we reported four new whole plastomes of Oxalidaceae and compared them with plastomes of three species in the family, as well as the plastome of Rourea microphylla in the closely related family Connaraceae. The eight plastomes ranged in length from 150,673 bp (Biophytum sensitivum) to 156,609 bp (R. microphylla). Genome annotations revealed a total of 129–131 genes, including 83–84 protein-coding genes, eight rRNA genes, 37 tRNA genes, and two to three pseudogenes. Comparative analyses showed that the plastomes of these species have minor variations at the gene level. The smaller plastomes of herbs B. sensitivum and three Oxalis species are associated with variations in IR region sizes, intergenic region variation, and gene or intron loss. We identified sequences with high variation that may serve as molecular markers in taxonomic studies of Oxalidaceae. The phylogenetic trees of selected superrosid representatives based on 76 protein-coding genes corroborated the Oxalidaceae position in Oxalidales and supported it as a sister to Connaraceae. Our research also supported the monophyly of the COM (Celastrales, Oxalidales, and Malpighiales) clade., Highlights • Plastomes from the genus Biophytum (Oxalidaceae) and the family Connaraceae are reported for the first time. • Little plastome variation was observed among genera of Oxalidaceae. • Several divergence hotspot regions were identified in the Oxalidaceae species. • The systematic position of Oxalidaceae was confirmed as sister to Connaraceae within Oxalidales.

Pseudocerastium is a monotypic genus in Caryophyllaceae endemic to China. The genus has been widely accepted since it was described in 1998, however its phylogenetic position within Caryophyllaceae has never been studied. In the present study, the whole plastid genome and nuclear ribosomal internal transcribed spacer (ITS) sequences of Pseudocerastium stellarioides was obtained through genome skimming, and the phylogenetic position of the species was studied for the first time. Plastid phylogenomic analysis of Caryophyllaceae revealed that Pseudocerastium is clustered within the tribe Alsineae with strong support. Phylogenetic analyses based on an enlarged taxon sampling of Alsineae using five DNA regions (matK, rbcL, rps16 intron, trnL-F and ITS) revealed that P. stellarioides was nested deeply within Cerastium with strong support. Analyses of morphological character evolution suggest that the ancestral states in Alsineae include three styles and a six-lobed capsule at the apex, while both Cerastium and Pseudocerastium have five styles and ten lobes at the apex of the capsule, further supporting their close relationship. The species Pseudocerastium stellarioides is similar to Cerastium wilsonii in morphology, but differs in having villous indumentum on the lower part of the filaments and compressed globose seeds. Therefore, based on the present molecular and morphological evidence, the generic name Pseudocerastium is reduced here as a new synonym of Cerastium and the species P. stellarioides is transferred to Cerastium as C. jiuhuashanense.

Due to the small degree of morphological and karyotype variations, the Pleione formosana, a well-known and valuable ornamental orchid, was treated as one member of the P. bulbocodioides complex including P. bulbocodioides, P. pleionoides and P. limprichtii, as well. The taxonomy of this complex remains problematic. P. hui was described in Anfu, Jiangxi, China, but was treated as synonym of P. formosana latter, making its taxonomic status remains controversy. In this study, we used molecular, morphological and cytological analyses to identify the relationship of P. formosana and other related species. Results base on phylogenetic analyses of chloroplast DNA and nuclear ribosomal Internal Transcribed Spacer sequence datasets indicated that Anfu samples were obviously separated from the P. formosana accessions. Network analysis showed three different groups: the P. formosana group, the P. bulbocodioides complex and the hybrid group. Morphological analysis also showed that Anfu population was significantly different from other P. formosana populations. Results of chromosome ploidy analyses showed that P. formosana was diploid and Anfu population was tetraploid, indicating that they are not the same species. In conclusion, we suggest to exclude P. formosana from P. bulbocodiodes complex, and restore the speceies rank of P. hui.

Two new bibenzyls (

A new orchid, Calanthe tsiana, is described from southeastern Yunnan, China, based on morphological and DNA evidence. In morphological comparisons, C. tsiana is similar to C. arisanensis, but it differs in having subspatulate petals and falcate-obovate lateral lobes of lip with one ridge on the disk. The phylogenetic analyses based on nuclear ribosomal ITS and plastid DNA (rbcL, matK and trnL-trnF) place C. tsiana with C. arisanensis as sister species and support C. tsiana as a new species.

Two new bibenzyls (1 and 2) were isolated from the pseudobulbs of Pleione grandiflora (Rolfe) Rolfe along with six known compounds, including isoarundinin I (3), isoarundinin II (4), bulbocodin D (5), batatasin III (6), 5,3'-dihydroxy- 4-(p-hydroxybenzyl)-3-methoxybibenzyl (7) and shancigusin F (8). Their structures were established on the basis of spectroscopic methods. These compounds showed potent DPPH free radical scavenging effects with IC50 values ranging from 49.72 ± 0.35 μM to 65.41 ± 0.49 μM.

Analyses of the genome sequences and expression data for two closely related mycoheterotrophic orchid species provide insights into the genomic basis underlying the evolution of mycoheterotrophy. To improve our understanding of the origin and evolution of mycoheterotrophic plants, we here present the chromosome-scale genome assemblies of two sibling orchid species: partially mycoheterotrophic Platanthera zijinensis and holomycoheterotrophic Platanthera guangdongensis. Comparative analysis shows that mycoheterotrophy is associated with increased substitution rates and gene loss, and the deletion of most photoreceptor genes and auxin transporter genes might be linked to the unique phenotypes of fully mycoheterotrophic orchids. Conversely, trehalase genes that catalyse the conversion of trehalose into glucose have expanded in most sequenced orchids, in line with the fact that the germination of orchid non-endosperm seeds needs carbohydrates from fungi during the protocorm stage. We further show that the mature plant of P. guangdongensis, different from photosynthetic orchids, keeps expressing trehalase genes to hijack trehalose from fungi. Therefore, we propose that mycoheterotrophy in mature orchids is a continuation of the protocorm stage by sustaining the expression of trehalase genes. Our results shed light on the molecular mechanism underlying initial, partial and full mycoheterotrophy.

Melastomataceae have abundant morphological diversity with high economic and ornamental merit in Myrtales. The phylogenetic position of Myrtales is still contested. Here, we report the first chromosome-level genome assembly of Melastoma dodecandrum in Melastomataceae. The assembled genome size was 299.81 Mb with a contig N50 value of 3.00 Mb. Genome evolution analysis indicated that M. dodecandrum, Eucalyptus grandis and Punica granatum were clustered into a clade of Myrtales and formed a sister group with the ancestor of fabids and malvids. We found that M. dodecandrum experienced four whole-genome polyploidization events: the ancient event was shared with most eudicots, one event was shared with Myrtales, and the other two events were unique to M. dodecandrum. Moreover, we identified MADS-box genes and found that the AP1-like genes expanded, and AP3-like genes might have undergone subfunctionalization. We found that the SUAR63-like genes and AG-like genes showed different expression patterns in stamens, which may be associated with heteranthery. In addition, we found that LAZY1-like genes were involved in the negative regulation of stem branching development, which may be related to its creeping features. Our study sheds new light on the evolution of Melastomataceae and Myrtales, which provides a comprehensive genetic resource for future research.

Coelogyne fimbriata has been classified as a national second-class protected orchid species in China. In this study, we report and characterize the complete chloroplast (cp) genome sequence of C. fimbriata in an effort to provide genomic resources useful for promoting its conservation and systematic research. The complete genome is 159,010 bp in length and the overall GC content is 43.3%. The cp genome sequence has a typical quadripartite structure, comprising two inverted repeats (IRA and IRB) regions, which are separated by a small single-copy (SSC) region and a large single-copy (LSC) region. Moreover, a total of 135 functional genes were annotated, including 89 protein-coding genes, 38 tRNA genes, and 8 rRNA genes. The phylogenetic analysis recovered a close relationship between C. fimbriata and Pleione formosana, and both species are placed within the tribe Arethuseae (Orchidaceae).

Calanthe arcuata is an endemic terrestrial orchid in China with high value of ornament and breeding. Here, we reported the first complete chloroplast genome of this plant in this research. The circular genome is 158,735 bp in length and includes large single-copy (LSC) region of 87,348 bp, small single-copy (SSC) region of 18,489 bp, and a pair of invert repeats (IR) regions of 26,449 bp. It contains 136 genes, including 88 protein-coding (PCG), 38 transfer RNA (tRNA), and eight ribosomal RNA (rRNA) gene. The phylogenetic analysis indicated that C. arcuata is the sister to C. davidii and C. triplicata.

Oxalidaceae is one of the most important plant families in horticulture, and its key commercially relevant genus, Averrhoa, has diverse growth habits and fruit types. Here, we describe the assembly of a high-quality chromosome-scale genome sequence for Averrhoa carambola (star fruit). Ks distribution analysis showed that A. carambola underwent a whole-genome triplication event, i.e., the gamma event shared by most eudicots. Comparisons between A. carambola and other angiosperms also permitted the generation of Oxalidaceae gene annotations. We identified unique gene families and analyzed gene family expansion and contraction. This analysis revealed significant changes in MADS-box gene family content, which might be related to the cauliflory of A. carambola. In addition, we identified and analyzed a total of 204 nucleotide-binding site, leucine-rich repeat receptor (NLR) genes and 58 WRKY genes in the genome, which may be related to the defense response. Our results provide insights into the origin, evolution and diversification of star fruit.

Natural indigo, as one of the oldest dyes, is also a pivotal dye utilized in cotton fabrics today. A diversity of plants rich in indigo compounds belong to traditional Chinese herbal medicines. Indigo compounds have a variety of biological and pharmacological activities, including anticonvulsant, antibacterial, antifungal, antiviral and anticancer activities. A substantial progress in indigo biosynthesis has been made lately. This paper summarizes the value of indigo from the aspects of cultural history, biosynthetic pathways and the medicinal activities of its related derivatives involved in the pathways. In addition, the latest research advancements in indigo biosynthetic pathways is demonstrated in this paper, which would lay the theoretical foundation for the exploration and utilization of natural indigo.

Floral color polymorphism can provide great insight into species evolution from a genetic and ecological standpoint. Color variations between species are often mediated by pollinators and are fixed characteristics, indicating their relevance to adaptive evolution, especially between plants within a single population or between similar species. The orchid genus Pleione has a wide variety of flower colors, from violet, rose-purple, pink, to white, but their color formation and its evolutionary mechanism are unclear. Here, we selected the P. limprichtii population in Huanglong, Sichuan Province, China, which displayed three color variations: Rose-purple, pink, and white, providing ideal material for exploring color variations with regard to species evolution. We investigated the distribution pattern of the different color morphs. The ratio of rose-purple:pink:white-flowered individuals was close to 6:3:1. We inferred that the distribution pattern may serve as a reproductive strategy to maintain the population size. Metabolome analysis was used to reveal that cyanindin derivatives and delphidin are the main color pigments involved. RNA sequencing was used to characterize anthocyanin biosynthetic pathway-related genes and reveal different color formation pathways and transcription factors in order to identify differentially-expressed genes and explore their relationship with color formation. In addition, qRT-PCR was used to validate the expression patterns of some of the genes. The results show that PlFLS serves as a crucial gene that contributes to white color formation and that PlANS and PlUFGT are related to the accumulation of anthocyanin which is responsible for color intensity, especially in pigmented flowers. Phylogenetic and co-expression analyses also identified a R2R3-MYB gene PlMYB10, which is predicted to combine with PlbHLH20 or PlbHLH26 along with PlWD40-1 to form an MBW protein complex (MYB, bHLH, and WDR) that regulates PlFLS expression and may serve as a repressor of anthocyanin accumulation-controlled color variations. Our results not only explain the molecular mechanism of color variation in P. limprichtii, but also contribute to the exploration of a flower color evolutionary model in Pleione, as well as other flowering plants.

Pleione (Orchidaceae) is not only famous for the ornamental value in Europe because of its special color, but also endemic in Southern Asia for its use in traditional medicine. A great deal of research about its secondary metabolites and biological activities has been done on only three of 30 species of Pleione. Up to now, 183 chemical compounds, such as phenanthrenes, bibenzyls, glucosyloxybenzyl succinate derivatives, flavonoids, lignans, terpenoids, etc., have been obtained from Pleione. These compounds have been demonstrated to play a significant role in anti-tumor, anti-neurodegenerative and anti-inflammatory biological activities and improve immunity. In order to further develop the drugs and utilize the plants, the chemical structural analysis and biological activities of Pleione are summarized in this review.

Calanthe s.l. is the most diverse group in the tribe Collabieae (Orchidaceae), which are pantropical in distribution. Illumina sequencing followed by de novo assembly was used in this study, and the plastid genetic information of Calanthe s.l. was used to investigate the adaptive evolution of this taxon. Herein, the complete plastome of five Calanthe s.l. species (Calanthe davidii, Styloglossum lyroglossa, Preptanthe rubens, Cephalantheropsis obcordata, and Phaius tankervilliae) were determined, and the two other published plastome sequences of Calanthe s.l. were added for comparative analyses to examine the evolutionary pattern of the plastome in the alliance. The seven plastomes ranged from 150,181 bp (C. delavayi) to 159,014 bp (C. davidii) in length and were all mapped as circular structures. Except for the three ndh genes (ndhC, ndhF, and ndhK) lost in C. delavayi, the remaining six species contain identical gene orders and numbers (115 gene). Nucleotide diversity was detected across the plastomes, and we screened 14 mutational hotspot regions, including 12 non-coding regions and two gene regions. For the adaptive evolution investigation, three species showed positive selected genes compared with others, C. obcordata (cemA), S. lyroglossa (infA, ycf1 and ycf2) and C. delavayi (nad6 and ndhB). Six genes were under site-specific positive selection in Calanthe s.l., namely, accD, ndhB, ndhD, rpoC2, ycf1, and ycf2, most of which are involved in photosynthesis. These results, including the new plastomes, provide resources for the comparative plastome, breeding, and plastid genetic engineering of orchids and flowering plants.

Dendrobium zhenghuoense is very distinctive among Orchidaceae species with yellowish-green flowers and short peduncle. In this study, we reported the complete chloroplast genome of D. zhenghuoense. Present study suggests that genomic information of D. zhenghuoense would have special importance in conservation and molecular phylogenetic studies on Orchidaceae. The circle genome of D. zhenghuoense was 148,431 bp in length with 37.0% GC content and a large single-copy (LSC) region of 84,167 bp, a small single-copy (SSC) region of 12,588 bp, which were separated by a pair of inverted repeat (IR) region of 25,838 bp. The genome contained 130 genes, including 75 protein-coding genes, 38 tRNA genes and 8 rRNA genes. The maximum likelihood phylogenetic analysis indicated that D. zhenghuoense was the sister to the rest 11 species of Dendrobium tested.

Calanthe arcuata is an endemic terrestrial orchid in China with high value of ornament and breeding. Here, we reported the first complete chloroplast genome of this plant in this research. The circ...

Apostasia shenzhenica is a terrestrial orchid, which belongs to Apostasioideae (Orchidaceae). Here, we determined the complete plastid genome of A. shenzhenica using the Illumina reads in an effort...

Calanthe delavayi, an endemic terrestrial orchid distributed in southwestern China. In this study, the complete chloroplast genome (cpDNA) sequence of C. delavayi was determined from Illumina pair-...

Goodyerinae are one of the most species-rich and widespread subtribes of Orchidaceae but notorious for their taxonomic difficulty. Here, a comprehensive molecular phylogenetic study of the subtribe is presented based on two nuclear (ITS, Xdh) and five plastid (matK, psaB, rbcL, trnL, trnL-F) regions. A total of 119 species were included representing all clades recovered by previous phylogenetic analyses as well as seven outgroups. Maximum parsimony, maximum likelihood and Bayesian inference methods were used to infer the phylogenetic relationships. The results show that the Goodyerinae subdivided into three major subdivisions and six groupings: Pachyplectron, Goodyera clade (including Goodyera procera, Microchilus subclade and Goodyera subclade) and Cheirostylis clade (including Gonatostylis, Cheirostylis subclade and Ludisia subclade). Four genera, Erythrodes, Goodyera, Myrmechis and Odontochilus, are not monophyletic. The results support Odontochilus s. l. to include Myrmechis and Kuhlhasseltia. The systematic positions of Goodyera procera and two isolated genera, Herpysma and Orchipedum, are difficult to determine.

Background There are different opinions about the relationship of two disjunctively distributed varieties Adiantum reniforme L. var. sinense Y.X.Lin and Adiantum reniforme L. Adiantum reniforme var. sinense is an endangered fern only distributed in a narrowed region of Chongqing city in China, while Adiantum reniforme var. reniforme just distributed in Canary Islands and Madeira off the north-western African coast. To verify the relationship of these two taxa, relative phylogenetic analyses, karyotype analyses, microscopic spore observations and morphological studies were performed in this study. Besides, divergence time between A. reniforme var. sinense and A. reniforme var. reniforme was estimated using GTR model according to a phylogeny tree constructed with the three cpDNA markers atpA, atpB, and rbcL. Results Phylogenetic results and divergence time analyses--all individuals of A. reniforme var. sinense from 4 different populations (representing all biogeographic distributions) were clustered into one clade and all individuals of A. reniforme var. reniforme from 7 different populations (all biogeographic distributions are included) were clustered into another clade. The divergence between A. reniforme var. reniforme and A. reniforme var. sinense was estimated to be 4.94 (2.26-8.66) Myr. Based on karyotype analyses, A. reniforme var. reniforme was deduced to be hexaploidy with 2n = 180, X = 30, while A. reniforme var. sinense was known as tetraploidy. Microscopic spore observations suggested that surface ornamentation of A. reniforme var. reniforme is psilate, but that of A. reniforme var. sinense is rugate. Leaf blades of A. reniforme var. sinense are membranous and reniform and with several obvious concentric rings, and leaves of A. reniforme var. reniforme are pachyphyllous and coriaceous and are much rounder and similar to palm. Conclusion Adiantum reniforme var. sinense is an independent species rather than the variety of Adiantum reniforme var. reniforme. As a result, we approve Adiantum nelumboides X. C. Zhang, nom. & stat. nov. as a legal name instead of the former Adiantum reniforme var. sinense. China was determined to be the most probable evolution centre based on the results of phylogenetic analyses, divergence estimation, relative palaeogeography and palaeoclimate materials. Electronic supplementary material The online version of this article (doi:10.1186/s12870-014-0361-9) contains supplementary material, which is available to authorized users.

Calanthe Brown (1821: t. 573) is widely distributed in tropical and subtropical Asia to the Pacific islands and Africa, with only one species distributed in northern South America. Infrageneric relationships of Calanthe and its close related genera, such as Phaius Lour. (1790: t2: 527, 529), Cephalantheropsis Guill. (1960: 188–189) and Gastrorchis Thouars ( Gastorkis , 1809: 317) has long been a controversial issue (Xiang et al. 2014; Zhai et al. 2014). A recent treatment suggested was accepted by most orchidologists that both of previously used as subgenus Preptanthe (1853: 245) and section Styloglossum (1829: [11] may well be elevated to the rank of genus (Zhai et al. 2014, Tomohisa Y. & Phillip C. 2014). According to this treatment, the revised Calanthe has about 150 species all over the world, and approximately 40 species in China (Chen et al. , 2009; Clayton & Cribb 2013).

A new orchid species, Liparis meihuashanensis, from Fujian, China is described and illustrated based on morphological and molecular analyses. Detailed morphological comparisons indicate that L. meihuashanensis is similar to L. auriculata and L. pauliana, but it can be distinguished from them by the shorter inflorescence, triangular floral bract, and a lip with a truncate-emarginate and mucronate apex and 2 small subconical calli on contracted base. Molecular analyses based on nuclear ITS and plastid matK DNA sequence data support the L. meihuashanensis as a distinct species.

Danxiaorchis yangii (Calypsoinae, Epidendreae, Epidendroideae), a holomycotrophic new species from Jinggangshan National Nature Reserve, western Jiangxi, eastern of China, is here illustrated and described based on both morphological and phylogenetic evidences. The new species can be easily distinguished from D. singchiana by its much smaller flowers and larger Y-shaped callus adaxially bearing a additional obovoid appendage, and by its four pollinia narrowly elliptic in shape and equal in size.

Bulbophyllum yingjiangense (Epidendroideae; Malaxideae), a new species from western Yunnan, China, is illustrated and described here based on morphological and phylogenetic evidence. The new species is phylogenetically close to B. rothschildianum, and they are also similar in floral morphology. The new species differs in its yellowish green flowers without stripes, pseudobulbs with obvious ridges, lateral sepals glabrous with short tails and leaf with white waxy powder on its adaxial surface.

The taxonomy of the Calanthe alliance (Epidendroideae, Orchidaceae), consisting of Calanthe, Cephalantheropsis, and Phaius, has been difficult for orchidologists to understand because of the presence of common morphological features. In this study, in addition to morphological and geographical analyses, maximum parsimony and Bayesian inference analyses were performed based on nucleotide sequences of the nuclear internal transcribed spacer and cpDNA genes of 88 taxa representing the major clades of the Calanthe alliance in China. The results indicated that Cephalantheropsis is monophyletic, while both Phaius and Calanthe are polyphyletic. In Phaius, a total of three species, P. flavus, P. columnaris, and P. takeoi, were segregated to form a new genus, Paraphaius. In Calanthe, subgenus Preptanthe and sect. Styloglossum were both categorized as distinct genera from Calanthe. Our results also confirm that Calanthe delavayi and C. calanthoides are members of Calanthe. Previous studies assigned C. delavayi to Phaius and C. calanthoides to Ghiesbrechtia. Five sections, namely, Alpinocalanthe, Puberula, Ghiesbrechtia, Tricarinata, and Calanthe, three of which are new taxa, were recognized in Calanthe. Therefore, we propose that the Calanthe alliance is composed of six genera: Calanthe, Cephalantheropsis, Paraphaius, Phaius, Preptanthe and Styloglossum.

BACKGROUND: Orchids have numerous species, and their speciation rates are presumed to be exceptionally high, suggesting that orchids are continuously and actively evolving. The wide diversity of orchids has attracted the interest of evolutionary biologists. In this study, a new orchid was discovered on Danxia Mountain in Guangdong, China. However, the phylogenetic clarification of this new orchid requires further molecular, morphological, and phytogeographic analyses. METHODOLOGY/PRINCIPAL FINDINGS: A new orchid possesses a labellum with a large Y-shaped callus and two sacs at the base, and cylindrical, fleshy seeds, which make it distinct from all known orchid genera. Phylogenetic methods were applied to a matrix of morphological and molecular characters based on the fragments of the nuclear internal transcribed spacer, chloroplast matK, and rbcL genes of Orchidaceae (74 genera) and Calypsoeae (13 genera). The strict consensus Bayesian inference phylogram strongly supports the division of the Calypsoeae alliance (not including Dactylostalix and Ephippianthus) into seven clades with 11 genera. The sequence data of each species and the morphological characters of each genus were combined into a single dataset. The inferred Bayesian phylogram supports the division of the 13 genera of Calypsoeae into four clades with 13 subclades (genera). Based on the results of our phylogenetic analyses, Calypsoeae, under which the new orchid is classified, represents an independent lineage in the Epidendroideae subfamily. CONCLUSIONS: Analyses of the combined datasets using Bayesian methods revealed strong evidence that Calypsoeae is a monophyletic tribe consisting of eight well-supported clades with 13 subclades (genera), which are all in agreement with the phytogeography of Calypsoeae. The Danxia orchid represents an independent lineage under the tribe Calypsoeae of the subfamily Epidendroideae. This lineage should be treated as a new genus, which we have named Danxiaorchis, that is parallel to Yoania. Both genera are placed under the subtribe Yoaniinae.

Calanthe Brown (1821: t. 573), with 217 species (WCSP, 2013), is widely distributed from tropical and subtropical Asia to the Pacific islands, tropical and southern Africa, Madagascar, Mexico, Panama and northern South America. Some 51 species are found in China, of which 23 are endemic (Chen S.C. et al. 2009). Over 80% of the Chinese species of Calanthe are found in southwestern China, and a number of new species or new distributions have been described in recent years, for example, Calanthe dulongensis Li, Li & Dao (2003: 267), Calanthe fugongensis Jin & Chen (2008: 20) and Calanthe alleizettii Gagnepain (1950: 508; Jin & Chen 2007). All evidence indicates the existence of a diversity centre of Calanthe in southwestern China.

Changnienia Chien (1935: 89) is a monotypic genus of tribe Calypsoeae endemic to eastern and central China (Chen et al. 1999, 2009, Freudenstein 2005), previously with only the species C. amoena Chien (1935: 90), which was listed in the Chinese Redbook in 1992 (Fu 1992). Yang & Zhu (1984) reported a chromosome number for it of 2n=46. Sun et al. (2006) observed pollination and found that Bombus trifasciatus was its pollinator. Zhai et al. (2013) confirmed the phylogenetic placement of this species as a member of tribe Calypsoeae (sensu Pridgeon et al. 2005). A new species of Changnienia is described and illustrated here based on molecular and morphological evidence. It is discovered in Malipo, Yunnan Province, China.