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Research Article
Impatiens chenmoui (Balsaminaceae), a new species from southern Yunnan, China
expand article infoZheng-wei Wang‡, Qi Wang‡, Ru-hua Xu§, Yu Zhang§, Xiao-chen Li‡
‡ Eastern China Conservation Center for Wild Endangered Plant Resources, Shanghai Chenshan Botanical Garden, Shanghai, China
§ Yunnan Yelantang Biological Technology Co., Ltd., Kunming, China

Corresponding author: Xiao-chen Li ( xiaochenensis@gmail.com )

Academic editor: Hugo de Boer
© 2022 Zheng-wei Wang, Qi Wang, Ru-hua Xu, Yu Zhang, Xiao-chen Li.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation: Wang Z-w, Wang Q, Xu R-h, Zhang Y, Li X-c (2022) Impatiens chenmoui (Balsaminaceae), a new species from southern Yunnan, China. PhytoKeys 214: 83-95. https://doi.org/10.3897/phytokeys.214.94898
Open Access

Abstract

Impatiens chenmoui (Balsaminaceae), a new species from southern Yunnan, China, was described and illustrated based on morphological and molecular evidence. This new species is morphologically most similar to Impatiens oblongata Ruchis. & Niet, but can be distinguished by 7–9 pairs of leaf veins, glabrous perianth, obovate upper petal, and capsule with trichome.

Keywords

China, Impatiens chenmoui, morphology, phylogeny, sect. Uniflorae

Introduction

The family Balsaminaceae contains two genera, the monotypic Hydrocera Blume (1825:241) and Impatiens Linnaeus (1753: 937) (APG Website, http://www.mobot.org/MOBOT/research/APweb/) Impatiens L. is a large genus of over 1000 species (Grey-Wilson 1980; Fischer 2004), mainly distributed in tropical and subtropical regions, with tropical Africa, Madagascar, southern India and Sri Lanka, eastern Himalayas (including SW China) and Southeast Asia as its five diversity centers (Song et al. 2003; Yuan et al. 2004; Yu et al. 2015). More than 270 species are currently known from China (Yu 2012), in which more than 200 species occurred in SW China (Chen et al. 2007), mainly distributed in Yunnan, Sichuan, Guangxi, Guizhou, and Xizang. Impatiens was divided into two subgenera, subgen. Clavicarpa S.X. Yu ex S.X. Yu & Wei Wang and subgen. Impatiens L. according to the latest phylogenetic studies. The latter was further subdivided into seven sections (sect. Fasciculatae, sect. Impatiens, sect. Racemosae, sect. Scorpioidae, sect. Semeiocardium, sect. Tuberosae, and sect. Uniflorae) (Yu et al. 2015). Several new species of sect. Uniflorae have been described from India, Myanmar, Cambodia, Vietnam, and China. (e.g. Cho et al. 2017; Yang et al. 2017; Ruchisansakun et al. 2018; Kim et al. 2019; Zhang et al. 2020) in recent years.

In September 2019, during fieldwork in Mengla County, Yunnan, an unfamiliar Impatiens species was collected and transplanted to Shanghai Chenshan Botanical Garden. The flower blossomed in December 2020, indicating its unusual identity which may be new to science. In November 2021, we made a botanical trip back to Mengla County to collect flowers and fruit specimens. After careful comparison of relevant species from the adjacent area, we finally concluded that these specimens represent a species new to science, and described it here.

Methods

Morphology study

Morphological characters of the new species and related ones were compared based on living plants and herbarium specimens, including the digital resource of type specimens from JSTOR Global Plants (https://plants.jstor.org/). Herbarium specimens were examined in Chenshan Botanical Herbarium (CSH, index herbarium, http://sweetgum.nybg.org/science/ih/herbarium-list/?NamOrganisationAcronym=CSH), original protologues and relevant literature were also investigated.

Datasets preparation

To resolve the phylogenetic position of the putative new species, two molecular markers ITS (ITS1–5.8S-ITS2) and atpB-rbcL were used in this study. Leaf material of the putative new species was collected from the field and stored with silica. Total genomic DNA was extracted with the modified CTAB method (Doyle and Doyle 1987) for library construction at Benagen (https://www.benagen.com). Paired-end sequencing of the whole sequences from both ends of 150 bp fragments was performed on the DNBSEQ T7, and about 2 Gb clean data were produced. The plastome and nrDNA were de novo assembled using the GetOrganelle pipeline 1.7.6.1 (Jin et al. 2020). Sequences of atpB-rbcL were extracted from the plastome annotated in Geneious Prime 2021.2.2 (https://www.geneious.com) with comparison to the published plastome of Impatiens balsamina L. (GenBank accession: MW411292) as reference. Sequences of ITS1–5.8s-ITS2 were extracted with ITSx 1.1.3 (Bengtsson-Palme et al. 2013). The ITS dataset and the atpB-rbcL dataset were respectively aligned using MAFFT v7.450 by default setting. (Katoh and Standley 2013) and concatenated for phylogenetic analysis (Chen et al. 2020). Species sampling was based on previous studies (Yu et al. 2015; Ruchisansakun et al. 2018). All the sequence GenBank accession numbers were listed in Appendix 1.

Phylogenetic analysis

Maximum Likelihood estimation (ML) and Bayesian inference analysis (BI) were performed on Phylosuite v1.2.2 (Zhang et al. 2020). For ML, GTR+F+R4 was selected as the best fit model for the ITS dataset, and GTR+F+R5 was selected as the best fit model for the atpB-rbcL dataset according to AICc by Modelfinder (Kalyaanamoorthy et al. 2017). Maximum likelihood was estimated using IQ-TREE (Nguyen et al. 2015) under the Edge-linked partition model for 2000 ultrafast (Minh et al. 2013) bootstraps. For BI, GTR+I+G was selected as the best fit model for both datasets according to AICc by PartitionFinder2 (Lanfear et al. 2017). Bayesian Inference phylogeny analysis was inferred using MrBayes 3.2.6 (Ronquist et al. 2012) under the partition model (2 parallel runs, 10,000,000 generations), in which the initial 25000 sampled data were discarded as burn-in. Tree files were visualized and annotated in Figtree v1.4.4 (http://tree.bio.ed.ac.uk/software/figtree/). Bootstrap (BS) and Posterior Probability (PP) values were used as an estimate of nodal robustness.

Result

The combined dataset was 1934bp in total, compromising 107 accessions/107 species, with Hydrocera triflora (L.) Wight. et Arn. selected as outgroup. Phylogenetic reconstruction of BI and ML produced similar topological structures (Fig. 1). The putative new species (marked in red) was resolved in the subgen. Impatiens sect. Uniflorae, forming a sister relationship with Myanmar species I. oblongata Ruchis. & Niet (PP = 0.957, BS = 94). Based on the morphological characters and phylogenetic result, we recognized this Impatiens species as a new species and described it here as Impatiens chenmoui Zheng W. Wang, Xiao C. Li & Qi Wang, sp. nov.

Figure 1. 

Phylogenetic tree based on combined datasets of the nuclear ITS and plastid atpB–rbcL DNA sequences. The topological structure comes from Bayesian inference. Numbers near nodes are PP/BS, a dash ‘–’ indicates nodes not supported, subgen. Clavicarpa was collapsed.

Taxonomic treatment

Impatiens chenmoui Zheng W. Wang, Xiao C. Li & Q.Wang ter, sp. nov.

urn:lsid:ipni.org:names:77309066-1
Figs 2, 3, Appendix 2

Type

China. Yunnan province, Mengla county (勐腊县) Xiangming Yi nationality township (象明彝族自治乡) Kongming Mountain (孔明山) alt.1639m, 22°8'9.73"N, 101°8'48.86"E, 23 November 2021, Zhengwei Wang and Xiaochen Li, WZW04250 (Holotype: CSH0189505, CSH!; isotypes: CSH0192380, ZJFC!; CSH0189507, HZU!; CSH0189506, JJF!).

Figure 2. 

Impatiens chenmoui sp. nov. A habit B, C flower with long spur D, E flower with spur nearly absent F leaf base G capsule H dorsal petal I spur J lateral sepals K united lateral petals L ovary surrounded by stamens.

Diagnosis

Impatiens chenmoui is most similar to I. oblongata Ruchis. & Niet, but is distinguished by the glabrous dorsal petal, pedicel, and bracts, longer pedicel and spur, and fewer lateral sepals (Table 1).

Table 1.
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Comparison of key features of I. chenmoui and I. oblongata.

Taxonomic traits I. chenmoui I. oblongata
Dorsal petal Glabrous midrib and tip pilose
Pedicel 25–27 mm long, green, glabrous. 18–20 mm long, pink, pilose.
Ovary hair Trichome Pilose
Spur 14–17 mm long, glabrous, rarely absent. 8–12 mm long, pilose.
Bracts Glabrous Pilose
Lateral sepals 2, inversely coiled, glabrous 2–4, upper pair pilose; lower pair glabrous
Figure 3. 

Impatiens chenmoui sp. nov. A habit B, C united lateral petals D ovary surrounded by stamens E flower front view F, G lateral sepals H spur I dorsal petal J–L leaves M seed N capsule O, P long-spurred flower side view Q non-spurred flower side view.

Description

Herb annual. Stem erect, fleshy, glabrous, 12–35 cm tall. Leaves alternate, petioles 1–5 cm, leaf blade 9.5–2.5×1.6–3.5 cm, narrowly elliptic or oblong-lanceolate, apex acuminate or long acuminate, base cuneate, margin roughly crenate; adaxially dark green, pilose along veins, abaxially gray-green, glabrous, lateral veins 7–9 pairs. Inflorescences in upper leaf axils, 1–flowered. Pedicels green, glabrous, 2.5 –2.7 cm long. Bracts linear, persistent, 2–3 mm long. Flowers solitary, axillary, pink, or lavender, with pair of darker pink and yellow dots at the base. Lateral sepals 2, inversely coiled, glabrous, green, 2 mm long. Lower sepal funnelform, 3–4×2–3mm long, 2–3mm in depth, eaves navicular, base gradually constricted into a spur, variable, usually1.4–1.7 cm long, rarely absent, mouth oblique, ca. 5mm wide, with ca. 2 mm long narrowly triangular tip. Dorsal petal circular, pink or mauve, 5–6×4–5mm, apex acuminate, glabrous, ca. 2mm long. United lateral petals sessile, 2–lobed, 6–8mm long. Upper petal large, obovate, 6–7×2–5mm, apex often concave. Lower petal small, axe-shaped, 7–8×1–3mm, apex rounded, without auriculus at back. Stamens 5, filaments linear, subulate, pale pink, ca. 2–3mm long, distally enlarged, anthers obtuse. Ovary fusiform, 5–carpellate, purple, 2–3 mm long, dorsal suture ridges with trichome. Capsule short fusiform, 12–18mm long, 4–5 mm in diam, with trichome along ridges. Seeds obovoid, brown, ca. 2 mm long, slightly compressed, pubescent with spirally sculptured hairs.

Phenology

Flowering and fruiting from October to December.

Distribution and ecology

This new species was found under evergreen broad-leaved forest at an elevation of 1500–1700 m on the limestone mountain ridge, and was currently known as only one population in Mengla County, Yunnan, China. This distribution area is very close to the border with Myanmar and Laos. We assume that this species should be also distributed in Myanmar and Laos due to their similar habitat.

Etymology

The specific epithet “Chenmoui” was dedicated to the famous Chinese collector and botanist, Chen Mou (陈谋) (1903–1935) who was one of the founders of the first botanical garden cataloged by the Classification System of Plants in China, and died during the collection trip through southern Yunnan, China. The Chinese name was given as “陈谋凤仙花”.

Conservation status

This species is currently known only from one population in the type locality. The population is located in the tourist area of Kongming Mountain, where it could be easily disturbed by human activities, such as road construction and illegal mining. The IUCN status proposed is Vulnerable(VU) based on IUCN (2022) guidelines.

Additional specimens examined

(Paratype). China,Yunnan province, Mengla county, Xiangming Yi nationality township, Kongming Mountain. 24 Oct. 2019, Ruhua Xu and Yu Zhang, XRH001 (CSH!).

Note

New species of sect. Uniflorae discovered from Southeast Asia in recent years were mostly found distributed on mountain summits in an evergreen forest, which indicated that the stone mountain in this area was likely to be one of the speciation centers of this section. Impatiens species exhibited interspecific and even intraspecific variation in spur length, at least from our observation of the same population of I. davidii Franchet, I. platysepala Y. L. Chen, and I. chenmoui, which may be considered as retaining of a bimodal pollinated system of bee and lepidopteran (Ruchisansakun et al. 2016). Floristic survey and pollination ecology study in these regions’ Impatiens species is still insufficient, and more fieldwork is urgently needed.

Acknowledgements

Our deepest gratitude goes to three reviewers and subject editor Hugo de Boer, for their careful work and thoughtful suggestions that have helped improve this paper substantially. We are grateful to Mr.Tian-Yi Yu for his excellent illustration in the manuscript, Mr. Xin Zhong for his sharp photo of the seed, and Mr. Zhi-jin Wu and Mr. Hong-jin Wei for their help during the fieldwork. The corresponding author is also indebted to Miss Pi for her company during the epidemic of COVID-19. This study was supported by the project of the National Wild Plant Germplasm Resource Center for Shanghai Chenshan Botanical Garden (ZWGX2102), the project of the Special Fund for Scientific Research of Shanghai Landscaping & City Appearance Administrative Bureau (G212416, G222404).

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Appendix 1

Table A1.
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Species and sequences sampling list with Genbank accession number.

Species ITS atpB–rbcL
Hydrocera triflora AY348853 DQ147895
Impatiens apalophylla KP776061 KP776011
Impatiens aquatilis AY348745 DQ147811
Impatiens arguta AY348746 DQ147812
Impatiens aureliana AY348747 DQ147814
Impatiens balansae KP776062 KP776012
Impatiens balsamina AY348749 DQ147816
Impatiens begoniifolia AY348752 DQ147819
Impatiens bicornuta AY348754 DQ147821
Impatiens blinii KP776063 KP776013
Impatiens campanulata AY348758 DQ147822
Impatiens capensis AY348759 DQ147823
Impatiens chekiangensis KP776064 KP776014
Impatiens chenmoui OP035808 OP095354
Impatiens chinensis AY348761 DQ147825
Impatiens chishuiensis KP776065 KP776015
Impatiens chiulungensis KP776066 KP776016
Impatiens chlorosepala KP776067 KP776017
Impatiens clavigera KP776068 KP776018
Impatiens conchibracteata AY348765 DQ147829
Impatiens corchorifolia AY348767 DQ147831
Impatiens cuspidata AY348769 DQ147832
Impatiens cyanantha AY348770 DQ147833
Impatiens cyathiflora AY348771 DQ147834
Impatiens cymbifera KP776069 KP776019
Impatiens davidii KP776070 KP776020
Impatiens decurva MF979085 MF979082
Impatiens delavayi AY348773 DQ147836
Impatiens desmantha AY348774 DQ147837
Impatiens drepanophora AY348776 DQ147838
Impatiens duclouxii KP776071 KP776021
Impatiens faberi AY348778 DQ147841
Impatiens falcifer KP776072 KP776022
Impatiens fischeri AY348781 DQ147843
Impatiens fissicornis AY348782 DQ147844
Impatiens flanaganae AY348783 DQ147846
Impatiens florulenta MF979087 MF979084
Impatiens forrestii AY348784 DQ147847
Impatiens fragicolor KP776073 KP776023
Impatiens gongshanensis KP776074 KP776024
Impatiens harae KP776075 KP776025
Impatiens hians AY348791 DQ147849
Impatiens hongkongensis KP776076 KP776027
Impatiens hunanensis KP776077 KP776028
Impatiens imbecilla AY348796 DQ147851
Impatiens inaperta AY348797 DQ147852
Impatiens lateristachys KP776078 KP776030
Impatiens laxiflora KP776079 KP776031
Impatiens lecomtei AY348802 DQ147855
Impatiens leptocaulon KP776080 KP776032
Impatiens macrovexilla KP776082 KP776034
Impatiens malipoensis KP776083 KP776035
Impatiens margaritifera KP776084 KP776036
Impatiens mengtzeana AY348806 DQ147858
Impatiens meruensis AY348807 DQ147859
Impatiens monticola AY348810 DQ147860
Impatiens muscicola KC905500 KC905547
Impatiens napoensis AY348811 DQ147861
Impatiens neglecta KP776087 KP776038
Impatiens noei KC905504 KC905548
Impatiens noli–tangere KP776088 KP776039
Impatiens nubigena KP776089 KP776040
Impatiens nyimana KP776090 KP776041
Impatiens oblongata MF979086 MF979083
Impatiens omeiana KP776092 DQ147864
Impatiens oxyanthera AY348814 DQ147865
Impatiens parviflora AY348816 DQ147866
Impatiens patula KC905509 KC905549
Impatiens phuluangensis KC905517 KC905554
Impatiens platychlaena AY348818 DQ147867
Impatiens platypetala AY348819 DQ147868
Impatiens poculifer AY348820 DQ147870
Impatiens principis KP776096 KP776026
Impatiens pritzelii AY348821 KP776045
Impatiens pseudoviola AY348822 DQ147871
Impatiens pterosepala KP776097 KP776046
Impatiens purpurea AY348823 DQ147872
Impatiens racemosa KP776098 DQ147873
Impatiens radiata AY348824 KP776047
Impatiens rectangula AY348825 DQ147874
Impatiens rubrostriata AY348828 DQ147876
Impatiens santisukii KC905528 KC905550
Impatiens scabrida KP776099 DQ147877
Impatiens scullyi KP776100 KP776048
Impatiens scutisepala AY348830 DQ147878
Impatiens siculifer KP776101 KP776049
Impatiens sodenii AY348832 DQ147879
Impatiens soulieana AY348833 DQ147880
Impatiens spathulata KP776102 KP776050
Impatiens stenosepala AY348835 DQ147881
Impatiens sulcata KP776103 KP776051
Impatiens sunkoshiensis KP776104 KP776052
Impatiens taronensis AY348838 DQ147882
Impatiens teitensis AY348840 DQ147883
Impatiens tienmushanica KP776105 KP776053
Impatiens tortisepala KP776106 KP776054
Impatiens trichosepala AY348843 DQ147885
Impatiens tuberculata KP776107 KP776055
Impatiens tubulosa KP776108 KP776056
Impatiens uliginosa AY348845 DQ147887
Impatiens usambarensis AY348847 DQ147890
Impatiens violiflora KC905541 KC905551
Impatiens walleriana AY348849 DQ147892
Impatiens wenshanensis KP776110 KP776057
Impatiens wilsonii KP776111 KP776058
Impatiens xanthina AY348850 DQ147893
Impatiens yaoshanensis KP776112 KP776059

Appendix 2

Figure A1. 

Holotype of Impatiens chenmoui sp.nov.

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