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Millettia is a complex genus of the tribe Millettieae (Fabaceae). In this paper we provide a synopsis of the species of the genus from Vietnam, based on the examination of literature and specimens as well as field surveys. Millettia boniana and M. setigera are proposed as new synonyms of Derris tonkinensis and M. cubittii, respectively. Millettia densiflora, a species most recently described from Laos, is newly reported in central and southern Vietnam. Millettia acutiflora is treated under the newly reinstated genus Imbralyx as I. acutiflorus. Twelve species and one variety are excluded from the list of Vietnamese species of Millettia. As a result, fourteen species and one variety of Millettia are recognized in Vietnam. A key to the species and lectotypification for seventeen names are provided.

Brachypterum was highly supported as a distinct genus from Derris within the tribe Millettieae by recent molecular and mophological evidence. Brachypterum pseudorobustum (basionym: Derris pseudorobusta) and Derris robusta var. assamica were originally described on fruiting collections from Northeast India, and their flowers were never described. The former species was considered be unique in having habit of scandent shrub, 15-foliolate leaves with minutely puberulous hairs, and one-winged pods usually with multiple seeds per pod. The latter taxon is still remained in Derris, although D. robusta has been accepted as Brachypterum robustum. However, our comparision of characters suggests the former species is quite similar with B. eriocarpum in various characters including its habit, leaf and pod traits, and the latter taxon most closely matches the features of Robinia pseudoacacia from the tribe Robinieae. As a result, Brachypterum pseudorobustum and Derris robusta var. assamica are both excluded from the accepted species list of Brachypterum in this study. A key to all the eleven accepted species of Brachypterum is first provided.

Imbralyx R. Geesink (Fabaceae: Millettieae) was long recognized as part of the genus Fordia Hemsl. However, Imbralyx has a unique characteristic combination of characters within Millettieae and it can be readily distinguished from Fordia and other genera of the tribe, including transitional inflorescences to pseudoracemes, distinctly imbricate calyx lobes in buds, spindle-shaped flowerbuds, white flowers, distinct hypanthium, monadelphous stamens, and glabrous leaflets with raised nervation on both surfaces. Recent molecular evidence also suggested that Imbralyx should be treated as a genus distinct from Fordia, because the two genera were placed respectively in two different main subclades within the core Millettieae, i.e. Canavanine group and Non-canavanie group, which is consistent with previous chemical evidence. So far the genus Imbralyx comprises nine species and two varieties from Asia, but only one epithet has been definitely associated with the generic name. Therefore, ten new combinations in Imbralyx are proposed in this paper. Additionally, lectotypes are re-designated here for the two basionyms Millettia albiflora Prain and M. unifoliata Prain.

Millettia puerarioides Prain within the tribe Millettieae (Fabaceae) is a poorly known species and it was previously reported only from Myanmar. This species was recently found also in Yingjiang, Yunnan Province, China. The inflated pods with large seeds place it in Millettia section Macrosperma Dunn, but specimen examination and field investigations showed that it has inflorescences arising from leafless nodes and directly from the trunk (i.e. rami- and caulinascent inflorescences), which is similar to the species in the genus Fordia from the same tribe. This inflorescence type has been considered to be a rare character for Asian plants of the subfamily Papilionoideae, showing the close connection between Millettia and Fordia.

Millettia lantsangensis Z.Wei was described within the tribe Millettieae on the basis of one fruiting and two flowering gatherings from Yunnan Province, China. Our critical examination shows that these gatherings are mixed and represent two distinct species from two different tribes. The fruiting specimens have woody branches, terminal infructescences and inflated pods, closely resembling Callerya sphaerosperma (Z. Wei) Z. Wei & Pedley from the same tribe, while the flowering collections have soft and herbaceous branches, axillary pseudoracemes and wart-like brachyblasts, and belong to Cruddasia insignis Prain from the tribe Phaseoleae. Because one of the flowering specimens was indicated as the type of Millettia lantsangensis, this is here reduced to a synonym of Cruddasia insignis. The genus Cruddasia Prain was previously reported only from Myanmar and Thailand, and is therefore a new genus record for the flora of China.

A comprehensive taxonomic revision of the genus Glochidion J.R. Forst. & G. Forst. from Taiwan in China was carried out based on the examination of herbarium specimens and filed investigations. Eight species and three varieties are recognized, including a new species endemic to Taiwan, G. lanyuense Gang Yao & S.X. Luo, which is described and illustrated. Three names, viz. G. chademenosocarpum Hayata, G. kusukusense Hayata, and G. ovalifolium F.Y. Lu & Y.S. Hsu, are reduced to the new synonyms of G. rubrum Blume, G. lanceolatum Hayata, and G. ellipticum Wight, respectively. Two names, viz. G. lanceolatum Hayata and G. suishaense Hayata, are lectotypified here. A key to the Glochidion species in Taiwan is provided.

Plant phenology was assessed as one of the most key Essential Biodiversity Variables on species functional traits, which underpins a variety of aspects of ecosystem function and is a vital determinant of species distribution. Flowering phenology is one of the most sensitive indicators of the effects of recent climatic change. Understanding of intraspecific variation in phenological responses to climate change can contribute to the accurate prediction of phenology and the assessment of potential impacts of climate change on organisms. However, this intraspecific variation in phenological sensitivity in natural systems is still unclear, especially at large spatial scales. Using the widespread perennial herb Spiranthes sinensis, we quantified intraspecific variation in phenological responses to warming among groups located along climatic gradients. Phenological data were derived from 1,681 collections of herbarium specimens and photographs across eastern Asia and southeastern Australia over the period 1902–2017 and spans eight humid and eight non‐humid regions. We found that peak flowering dates of Spiranthe sinensis (FLss) showed substantial intraspecific variation in temperature sensitivity, ranging from −5.16 ± 1.13 to 4.16 ± 0.90 days/°C. Across all 16 regions, FLss exhibited the strongest delayed response to warming in southeastern Australia. Temperature sensitivity of the FLss was significantly correlated with annual precipitation and aridity index of a region, suggesting a possible role of declined water availability in reducing temperature sensitivity. Notably, contrasting phenological responses to warming were found between collections with different humidity regimes: humid regions generally flowered earlier (M: −3.57 days/°C) and non‐humid regions exhibited slightly delayed flowering (M: 1.25 days/°C). These findings provide empirical evidence of substantial intraspecific variation in phenological sensitivity across large spatial scales, and highlights that soil water availability may play a key role in a warming planet, especially in non‐humid regions.

Millettia Wight & Arn. is a heterogeneous genus within the tribe Millettieae (Leguminosae) and has long been used as a repository to accommodate all undistinctive species of the tribe with elastically dehiscent pods. Millettia sect. Podocarpae Dunn is representative of the heterogeneous genus. This section includes five Asian species that have a unique combination of characters that distinguishes them from all other species of the genus, including the deciduous tree habit, conspicuous buds covered with scales, pseudoracemes or pseudopanicles with very indistinct brachyblasts, two flowers per brachyblast, conspicuous large bracts, ebracteolate calyx, well-developed hypanthium, stipitate ovary, and flat, stipitate and dehiscent pods. Our molecular phylogeny based on plastid matK and nuclear ribosomal ITS sequences also suggested the section is clearly monophyletic, separate from other congeneric species, and is most closely related to Antheroporum Gagnep. with inflated, vacuous pods and Ohashia X.Y. Zhu & R.P. Zhang with indehiscent flat pods. Therefore, we propose a new genus, Huchimingia Z.Q. Song & Shi J. Li, to accommodate this distinct section.

Derris Lour. and Millettia Wight & Arn. are two genera of the tribe Millettieae (Fabaceae). The biggest difference between the two genera is that Derris has indehiscent, thin and winged pods, while Millettia has dehiscent, compressed and wingless pods, but some exceptions also exist. Because of their tardily dehiscent, inflated and wingless pods, two Asian liana species, Millettia pachycarpa Benth. and M. entadoides Z. Wei, were previously placed in Millettia sect. Macrospermae Dunn. However, their vegetative and floral characters, as well as the shape of seeds match with those of Derris very well. Phylogenetic analyses based on three chloroplast markers (trnK/matK, trnL-F IGS, and psbA-trnH IGS), and nuclear ITS/5.8S showed that the two species are nested within Derris, and separate from other samples of Millettia species with strong support. Therefore, the two species should be transferred from Millettia to Derris to maintain the monophyly of the latter, which inevitably results in an emendation of the generic circumscription of Derris. Due to the existence of Derris pachycarpa Merr., the second earliest valid epithet “taiwaniana” should be used for this taxon when transfering Millettia pachycarpa Benth. to Derris. Thus, a new combination, Derris taiwaniana (Hayata) Z.Q. Song, is proposed here. Millettia entadoides Z. Wei is recombined as Derris entadoides (Z. Wei) Z.Q. Song. The floral morphology of D. entadoides is described here for the first time, and it is reported as a new record from Thailand in this study.

Verdesmummenglaense (C. Chen & X. J. Cui) H. Ohashi & K. Ohashi is a rare species in the tribe Desmodieae (Fabaceae) from Southwest China. The morphological observation shows that the species has minute capitate stigma and ebracteolate calyces, which are entirely different from the funnel-shaped stigma and bracteolate calyces of the genus Verdesmum H. Ohashi & K. Ohashi, but are consistent with those of the genus Hylodesmum H. Ohashi & R. R. Mill. The generic placement of V.menglaense within Hylodesmum was further supported by molecular evidence. Therefore, this species should be returned to Hylodesmum as H.menglaense (C. Chen & X. J. Cui) H. Ohashi & R. R. Mill. A full description including floral characters, a colour plate and a distribution map are first provided here for this species. After excluding the solo representative in China, Verdesmum should be removed from the record in Flora of China.

Millettia and Derris are two taxonomically complicated genera of the tribe Millettieae (Leguminosae), and when only flowering material is available they are not easily distinguished from each other. A critical examination of literature and specimens as well as a field survey show that Millettia sapindifolia T. C. Chen, a Chinese species described on the basis of two flowering collections, is conspecific with Derris yunnanensis Chun & F. C. How. The two are closely similar in various characters, such as the inflorescence type, monadelphous stamens, branches with longitudinal ridges, and size, shape, number and hairiness of leaflets. Therefore, the former is here reduced to a synonym of the latter.

Latitudinal patterns can reveal important ecological processes. The temporal overlap and divergence in flowering along latitudinal gradients is tightly related to intraspecific gene flow and interspecific interactions. Recent studies have predicted that global warming has led to more uniform spring and summer plant phenology across latitudes, but direct evidence is limited. Here, we test changes in the latitudinal pattern of peak flowering of a perennial herb Spiranthes sinensis (Orchidaceae) during 1901–2017 across ~40° of latitude in eastern Asia, spanning humid to water-limited regions. We found that flowering phenology did not vary significantly across latitudes in water-limited regions. However, global warming has significantly increased temporal divergence in flowering phenology across latitudes in humid regions—each 1 °C warming in mean annual temperature leads to an increased divergence of 2.47 days across 1° of latitude. Significantly stronger temperature sensitivity at lower latitudes is likely responsible for the increased phenological divergence. Additionally, we found that the phenological divergence is larger at lower latitudes in humid regions. These findings provide empirical evidence of variation in the latitudinal phenology shift at longer temporal and larger spatial scales under climate change, and highlight its potential role in ecosystem functioning, such as intraspecific gene flow and interspecific interaction.

Examination of both specimens and literature has shown that Mycetia coriacea (based on Adenosacme coriacea; Rubiaceae) has apically dehiscent dry capsules, quite different from the indehiscent berries of other species of the genus Mycetia. In various characters including the fruits, the species is found to be identical with the newly described species Foonchewia guangdongensis, the only species of the genus Foonchewia and the tribe Foonchewieae. Therefore, the new combination Foonchewia coriacea is here proposed to replace F. guangdongensis.

A new species of Rubiaceae, Mycetia fangii, is described and illustrated from Guangxi, South China. The new species morphologically resembles M. mukerjiana but differs in the calyx bearing one short gland on each sinus, the calyx lobes much shorter than the corolla, and shorter bracts and bracteoles. It is one of the species with cauliflorous inflorescences in Mycetia. Further examination of herbarium specimens shows that M. apoensis, M. yatesii, and M. lanceolata (Ridl.) Ridl. (non Miq.) are conspecific with M. cauliflora, the type species of the genus. Thus the three names are here reduced to synonymy of the type species. A key to the species of the genus with cauliflory is provided at the end of this paper.

Accurate forecasting of spring plant phenology is critical for understanding structural and functional changes in plant communities and their ecosystems in light of global warming. To date, the relative importance of winter chilling and photoperiod for leaf-out and flowering phenology remains unknown in subtropical and tropical forests. Here, we established a climate chamber experiment to test the effects of photoperiod and chilling on the timing of leaf-out and flowering for 37 subtropical woody species using dormant twigs. We found that most cuttings reached leaf-out, but only a few cuttings reached flowering. Longer chilling (including both moderate and strong chilling treatments) may improve leaf-out success and advance leaf-out timing, but it showed little effect on flowering. Moderate chilling was enough for the initiation of leaf-out. Photoperiod showed little effect on both leaf-out and flowering. To our knowledge, our study is the first to explore how different winter chilling conditions may lead to tree phenology progressing in various subtropical species in a new order and to show that leaf-out order is largely unpredictable when chilling requirements are not met. Our experiment indicates that dormant twigs of subtropical woody species can be successfully applied to leaf-out rather than flowering. Our results suggest that lack of chilling not only led to a considerable delay in leaf-out for subtropical species, but it also caused substantial changes in the order of species leaf-out. Thus, warmer winter temperatures might impact subtropical forest ecosystems more than formerly believed.

Bulbophyllum yarlungzangboense, a new species of Orchidaceae from Tibet, China is described and illustrated, it is morphologically similar to B. gamblei and B. shweliense, but can be easy distinguished from the later by petals ovate-oblong, stelidis triangular, base of column foot with V-shape cushion. The new species is tentatively assigned to sect. Desmosanthes based on morphological characters.

The non-monophyletic genus Fordia is hardly distinguished from some taxa of the polyphyletic genus Millettia of the same tribe Millettieae (Fabaceae). Examination of both literature and specimens shows that the Chinese species Fordia microphylla is conspecific with the widely distributed species Millettia pulchra. Some nomenclatural questions on Fordia microphylla are clarified, and the lectotype of Millettia pulchra is designated.

Myrioneuron R. Brown ex J. D. Hooker in Bentham & Hooker (1873: 69) comprises about eight species of the family Rubiaceae and it is distributed in East Himalaya to South China (Govaerts et al. 2011). Although it was occasionally treated as a synonym of Mycetia Reinwardt (1825: 9) (Bakhuizen 1975) or Keenania J. D. Hooker (1880: 101) (Van Steenis 1987, Robbrecht 1988), most botanists accepted it as a distinct genus (Kurz 1877, Hooker 1880, Schumann 1891, Pitard 1923, Merrill 1942, Bremekamp 1952, Deb 1996, Lo 1999, Wright 1999, Kress et al. 2003; Chen & Taylor 2011, Govaerts et al. 2011). Most recently, however, a molecular phylogenetic study revealed that Myrioneuron and Mycetia are non-monophyletic and intermixed, and therefore both taxa were combined to represent a monophyletic genus and Mycetia was accepted as its generic name (Ginter et al. 2015). In the study, they published nine new combinations, including Mycetia angustifolia (J. D. Hooker 1880: 97) Razafim. & B. Bremer in Ginter et al. (2015: 293). However, this name is illegitimate because it is a later homonym of Mycetia angustifolia Ridley (1923: 68), in accordance with Article 53.1 of the ICN (McNeil et al. 2012).

The genus Ailanthus Desfontaines (1788: 265) of the family Simaroubaceae comprises 5–10 species distributed in South and Southeast Asia as well as northern Australia (Nooteboom 1962, Peng & Thomas 2008). The species can be classified into two groups, i.e., one with toothed leaflets and the other with entire-margined leaflets. The latter group currently includes five species, A. triphysa (Dennstedt 1818: 32) Alston (1931: 41), A. vietnamensis H.V.Sam & Nooteboom (2007: 555), A. fordii Nooteboom (1962: 220), A. integrifolia Lamarck (1792: 417), and A. guangxiensis S.L.Mo ex C.F.Liang & S.L.Mo (1982: 145). The last species was described based on two fruit collections from Longzhou County, Guangxi Province, China. In the protologue, the authors stated that it was clearly distinguished from its congeneric species by the large samaras. After that, A. guangxiensis is always considered as an endemic species of Guangxi (Peng & Thomas 2008, Qin & Liu 2010, Mo 2011). In 2010, it was listed as a key protected wild plant of Guangxi by the local government.

Background The pantropical genus Bauhinia, along with the northern temperate Cercis and several tropical genera, bear bilobate, bifoliolate, or sometimes unifoliolate leaves, which constitute the tribe Cercideae as sister to the rest of the family Leguminosae based on molecular phylogenetics. Hence, the fossil record of Cercideae is pivotal to understand the early evolution and biogeographic history of legumes. Results Three fossil species of Bauhinia were described from the Oligocene Ningming Formation of Guangxi, South China. Bauhinia ningmingensis sp. nov. is characterized by its bifoliolate, pulvinate leaves bearing basal acrodromous primary veins and brochidodromous secondary veins. B. cheniae sp. nov. bears moderately or deeply bilobate, pulvinate leaves, with basal actinodromous primary veins and eucamptodromous secondary veins. B. larsenii D.X. Zhang et Y.F. Chen emend. possesses shallowly or moderately bilobate, pulvinate leaves bearing basal actinodromous primary veins and brochidodromous secondary veins, as well as elliptic, stipitate, non-winged, and oligo-seeded fruits. Meanwhile, previously reported Bauhinia fossils were reviewed, and those pre-Oligocene foliage across the world are either questionable or have been rejected due to lacking of reliable evidence for their pulvini or/and basal actinodromous or acrodromous venations. Besides Oligocene leaves and fruits presented here, foliage and/or wood of Bauhinia have been documented from the Miocene–Pliocene of Thailand, India, Nepal, Uganda, and Ecuador. Conclusions Bauhinia has exhibited a certain diversity with bifoliolate- and bilobate-leafed species in a low-latitude locality–Ningming since at least the Oligocene, implying that the tropical zone of South China may represent one of the centres for early diversification of the genus. The reliable macrofossils of Bauhinia and Cercis have made their debut in the Eocene–Oligocene floras from mid-low latitudes and appeared to lack in the coeval floras at high latitudes, implying a possible Tethys Seaway origin and spread of legumes. However, detailed scenarios for the historical biogeography of Bauhinia and its relatives still need more robust dataset from palaeobotany and molecular phylogeny in future research.