We review achievements in the conservation of orchid diversity in China over the last 21 years. We provide updated information on orchid biodiversity and suggestions for orchid conservation in China. We outline national policies of biodiversity conservation, especially of orchid conservation, which provide general guidelines for orchid conservation in China. There are now approximately 1708 known species of Orchidaceae in 181 genera in China, including five new genera and 365 new species described over the last 21 years. The assessment of risk of extinction of all 1502 known native orchid species in China in 2013 indicated that 653 species were identified as threatened, 132 species were treated as data-deficient, and four species endemic to China were classified as extinct. Approximately 1100 species (ca. 65%) are protected in national nature reserves, and another ~66 species in provincial nature reserves. About 800 native orchid species have living collections in major botanical gardens. The pollination biology of 74 native orchid species and the genetic diversity and spatial genetic structure of 29 orchid species have been investigated at a local scale and/or across species distributions. The mycorrhizal fungal community composition has been investigated in many genera, such as Bletilla, Coelogyne, Cymbidium, Cypripedium, and Dendrobium. Approximately 292 species will be included in the list of national key protected wild plants this year. Two major tasks for near future include in situ conservation and monitoring population dynamics of endangered species.

Bulbophyllum is the largest genus in Orchidaceae with a pantropical distribution. Due to highly significant diversifications, it is considered to be one of the most taxonomically and phylogenetically complex taxa. The diversification pattern and evolutionary adaptation of chloroplast genomes are poorly understood in this species-rich genus, and suitable molecular markers are necessary for species determination and phylogenetic analysis. A natural Asian section Macrocaulia was selected to estimate the interspecific divergence of chloroplast genomes in this study. Here, we sequenced the complete chloroplast genome of four Bulbophyllum species, including three species from section Macrocaulia. The four chloroplast genomes had a typical quadripartite structure with a genome size ranged from 156,182 to 158,524 bp. The chloroplast genomes included 113 unique genes encoding 79 proteins, 30 tRNAs and 4 rRNAs. Comparison of the four chloroplast genomes showed that the three species from section Macrocaulia had similar structure and gene contents, and shared a number of indels, which mainly contribute to its monophyly. In addition, interspecific divergence level was also great. Several exclusive indels and polymorphism SSR loci might be used for taxonomical identification and determining interspecific polymorphisms. A total of 20 intergenic regions and three coding genes of the most variable hotspot regions were proposed as candidate effective molecular markers for future phylogenetic relationships at different taxonomical levels and species divergence in Bulbophyllum. All of chloroplast genes in four Bulbophyllum species were under purifying selection, while 13 sites within six genes exhibited site-specific selection. A whole chloroplast genome phylogenetic analysis based on Maximum Likelihood, Bayesian and Parsimony methods all supported the monophyly of section Macrocaulia and the genus of Bulbophyllum. Our findings provide valuable molecular markers to use in accurately identifying species, clarifying taxonomy, and resolving the phylogeny and evolution of the genus Bulbophyllum. The molecular markers developed in this study will also contribute to further research of conservation of Bulbophyllum species.

Eight new species from China, Cheirostylis chuxiongensis, C. yei, Myrmechis lingulata, M. longii, Bulbophyllum ximaense, B. xizangense, B. retusum and B. pulcherissimum, are described and illustrated. Cheirostylis chuxiongensis differs from C. thailandica by having 5-9 irregular and papillae-like calli on each side in the sac of the lip, epichile with entire lobes, petals narrowly obliquely obovate and an apex that is not recurved. Cheirostylis yei is easily distinguished from its relatives similar by having a long stem, pubescent ovary and sepals, epichile lobes with irregular and undulate margins, a subquadrate callus without teeth in the saccate hypochile. Myrmechis lingulata differs from M. chinensis by having a simple and lanceolate to ligulate lip, glabrous bracts and ovary, oblique and narrowly ovate petals. Myrmechis longii differs from M. pumila by having white-veined leaves, oblong-lanceolate epichile lobes, and viscidium attached to the middle of the caudicle. Bulbophyllum ximaense is easily distinguished from its relatives similar by having distant pseudobulbs, shorter scape, an inflorescence with 9-16 orange-red flowers, shorter lateral sepals with a long acuminate apex, incurved and tubular apical margins, a papillate lip disk and triangular-subulate stelidia. Bulbophyllum xizangense is easily distinguished from its relatives similar by having narrow lanceolate leaves, shorter inflorescence with 1-3 greenish-yellow flowers, falcate-ovoid lateral sepals, a lip with small lateral lobes and 3 keels at the base. Bulbophyllum retusum differs from B. spathulatum by having shorter inflorescence, peduncles with 2 tubular sheaths, dorsal sepals with a retuse apex, lateral sepals with lower edges that are connate to each other and free and divergent toward the apex, obovate petals with an acute or slightly retuse apex. Bulbophyllum pulcherissimum differs from B. lopalanthum by its 5-veined dorsal sepal, ovate-lanceolate lateral sepals, obliquely ovate-oblong petal, erose-toothed margins and obovate lip with a large, oblong basal callus, and an obtuse base. In addition, three species (Bulbophyllum frostii, B. raskotii and B. nematocaulon) are reported for the first time in China.

Five new species (Gastrochilus yei, Gastrochilus minimus, Luisia simaoensis, Taeniophyllum xizangense, Tuberolabium subulatum) and two newly recorded species (Cleisostoma tricornutum, Luisia inconspicua) of Vandeae (Orchidaceae) from China are described and illustrated. Gastrochilus yei is similar to G. affinis and G. nepalensis, but differs from them by having an epichile not lobed, the apex of the hypochile not bilobed, and a tine on the apex of the leaf. Gastrochilus minimus is similar to G. acinacifolius, but can be distinguished from the latter by having a flabellate epichile that is densely hirsute on the adaxial surface and an inconspicuous central cushion; in addition, the hypochile of G. minimus has a keel that extends to the apex of the epichile. Taeniophyllum xizangense is similar to T. stella and T. radiatum, but it is distinguished from them by having much bigger flowers, inflorescences densely covered with short-bristly hairs, papillae on the external surface of sepals, and bigger triangular-ovate viscidium. Luisia simaoensis is similar to L. magniflora and L. ramosii, but can be easily distinguished from them by having lateral sepals longer than dorsal sepals and petals, lip with irregular and waved margins, and lip with bilobed apex. Luisia inconspicua is moved from Gastrochilus to Luisia based on phylogenetic analyses of plastid matK sequence data. Tuberolabium subulatum is similar to T. carnosum, but it can be easily distinguished from the latter by having an inflorescence much shorter than the leaves, yellow sepals and petals, and many small papillae outside the lip lobes.

Four new species of Orchidaceae from China, Heminium lijiangense, Peristylus fasciculatus, Platanthera milinensis, and Ponerorchis gongshanensis, together with a new country record, Peristylus tenuicallus, are described and illustrated based on morphological and/or phylogenetic analyses. Heminium lijiangense is closely related to H. elisabethae but differs from it by having the dorsal sepal ovate-orbicular and lip mid-lobe distinctly shorter than lateral lobes. P. fasciculatus is close to Peristylus tradescantifolius but is distinguished from it by having several fascicled and straight, root-like tubers (vs. one or two oblongoid tubers), old stems usually persistent, middle lobe of lip narrowly ligulate-lanceolate and half as long as the lateral lobes (vs. middle lobe deltoid, about a third as long as the lateral lobes or less), a raised callus at the base of each lateral lobe (vs. callus absent), spur gradually attenuate toward the apex (vs. spur clavate). Platanthera milinensis is similar to P. stenochila by sharing small green flowers and lip without a spur, but differs in having a creeping rhizome, a corymbose inflorescence, and a broadly ovate and slightly 3-lobed lip. Ponerochis gongshanensis is similar to P. faberi in its small flowers, but differs in having a linear leaf c. 3 mm wide (vs. leaf 5-13 mm wide), in the lip having collar-like raised margins on the sides of the spur entrance, and a mid-lobe which is notched at the apex but not divided into two divergent lobules that are nearly as large as the lateral lobes, as in P. faberi. All the proposed species obtained high support in phylogenetic analysis as new species. The recently described genus Apetalanthe is reduced to synonymy of Ponerorchis and a new combination is made.

Liparis aureolabella and L. mengziensis, two new species from the karst region of southwestern China, and L. bingzhongluoensis, a new species from montane region in Yunnan, are described and illustrated. L. aureolabella is easily distinguished from its relatives by having abaxially purple leave with purple reticulate veins prominent adaxially, a lip auriculate at base, and falcate-lanceolate pollinia. Liparis mengziensis is closely related to L. petiolata and L. auriculata, but differs from them by having an ovate to broadly ovate leaf, purple lip and apex connate along the margins. Liparis bingzhongluoensis is similar to Liparis nanlingensis, but the new species is characterized by having a lip with two transparent ridges on its disc, longitudinally concave basal callus and triangular column wings. Phylogenetic analyses based on nuclear ribosomal ITS and plastid matK sequences showed that L. aureolabella and L. mengziensis are nested with L. petiolata or L. auriculata in a monophyletic clade. L. bingzhongluoensis is sister to a clade formed by L. nanlingensis, L. tsii, L. sasakii and L. krameri. Moreover, morphological comparisons strongly support that the three species as separated species newly to science.

Corallorhiza sinensis, a new species of mycoheterotrophic orchid from western Sichuan, China, is described and illustrated based on molecular and morphological evidence. It is morphologically similar to Corallorhiza trifida, but can be distinguished by bigger flowers, both sepals and petals with 3 veins, and longer lateral lobes of lip. To distinguish the new Corallorhiza species and explore its phylogenetic position within subtribe Calypsoinae, this study employed sequences of the nuclear ribosomal DNA (nrDNA) and whole plastome assembled from the genome skimming approach. The plastome is 148,124 bp in length, including a pair of inverted repeats (IRs) of 26,165 bp, a large single-copy region (LSC) of 82,207 bp, and a small single-copy region (SSC) of 13,587 bp. Further, phylogenetic analyses were performed using nrDNA sequence and 79 coding sequences (CDSs) from 26 complete plastomes of subtribe Calypsoinae. The phylogenetic tree based on nrDNA sequence suggested that Corallorhiza is a monophyletic group, and strongly support C. sinensis as sister to the rest species of Corallorhiza. The plastid tree showed that 10 Corallorhiza species grouped into two clades and C. sinensis is most closely related to the North American C. striata and C. bentleyi instead of Oreorchis foliosa and O. angustata in the same clade. The plastid tree and nrDNA tree indicate Oreorchis is a paraphyletic. Although the topological conflicts are displayed between plastome and nrDNA phylogenies of C. sinensis, it is still the most closely related to Corallorhiza. Comparative analysis showed that C. sinensis populations are characteristic of the intermediate morphological traits between Corallorhiza and Oreorchis. The finding of this new species from China shed new light on the phylogeny of Oreorchis and Corallorhiza.

Gastrodia longistyla, a new species of Orchidaceae from Yunnan Province, China, is described and illustrated. It is morphologically similar to Gastrodia peichatieniana, but can be easily distinguished from the latter by having a rhombic epichile, long column (6.0-7.5 mm long), and a needle-shaped appendage (1.8-3.2 mm in length) at the base of the stigma. Identification key and colour photographs are provided. A preliminary risk-of-extinction assessment, according to the IUCN Red List Categories and Criteria, is given for the new species. The plastome of G. longistyla is 30464 bp in length with GC content approximately 24.8%, and the plastome does not contain some housekeeping genes, such as matK, rpl16, or all photosynthesis genes. In addition, the G. longistyla plastome lacks an IR region. This indicates that the plastome is in the last stage of degradation.

A new species, Neottia wuyishanensis (Neottieae, Orchidaceae), is described and illustrated from Wuyishan, Fujian, eastern China, based on morphological characters and molecular data. Molecular phylogenetics indicate that N. wuyishanensis is nested within the clade formed by Neottia fugongensis and Neottia nujiangensis. Morphologically, N. wuyishanensis is similar to N. fugongensis and N. pseudonipponica, but differs from them by having indistinct auricles at the base, and in the shape and size of lobelets.