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Tongoloa arguta (Apiaceae), a new species from southwest China
expand article infoLing-Jian Gui, Jun Wen, Yan-Ping Xiao, Ting Ren, Hong-Yi Zheng, Xing-Jin He
‡ Sichuan University, Chengdu, China
Open Access

Abstract

A new species Tongoloa arguta (Apiaceae) is described and illustrated in this article. The new species grows in alpine bushes and meadows in south-western China. It resembles T. silaifolia, but differs from the latter by the length of the stem, ultimate segments of leaf and rays of the umbel. Phylogenetic analysis, based on nuclear ribosomal DNA internal transcribed spacer (ITS) sequences, is provided, as well as comparative morphology between related species.

Keywords

Apiaceae, China, new species, phylogeny, Tongoloa

Introduction

Tongoloa H.Wolff (Apiaceae) is a genus comprising about 15–20 species distributed mainly in southwest China, with a few species extending westwards to central Nepal (Watson 1999; Pan and Watson 2005; Zhou et al. 2009). Tongoloa species are characterised by having conic taproots, inflated and membranous leaf sheaths, cordate fruit base and filiform fruit ribs (Wolff 1925; Mukherjee and Constance 1991; Pimenov and Kljuykov 2000; Pan and Watson 2005). Some species have been described in Pimpinella L. due to the morphological similarity (Boissieu 1902, 1906). The genus Tongoloa was formally established by Wolff (1925) and accepted as an independent genus (Pimenov and Kljuykov 1995; Pimenov 2017). Molecular phylogenetic analyses, based on limited materials of nuclear ribosomal DNA internal transcribed spacer (ITS) and chloroplast markers, indicated that Tongoloa is part of the East Asia clade of Apioideae (Apiaceae) (Zhou et al. 2009; Downie et al. 2010).

So far, 15 species of Tongoloa have been identified from different regions of China (Pimenov 2017), most of which being known from the Hengduan Mountains. While studying specimens in herbariums (CDBI, PE), we noticed several interesting specimens of Tongoloa collected from Sichuan and Yunnan, which have short stems and fewer rays of the umbel (3–8). Through field investigation and anatomical study, we confirmed that this species does not match any previously-published description of Tongoloa found from southwest China to central Himalaya. Further molecular analysis revealed significant differences between this species and its relatives. The results allow us to infer that these newly-collected specimens from Sichuan and Yunnan belong to a new species.

Materials and methods

We collected an unknown Tongoloa species from several populations in Yunnan and Sichuan Provinces. In addition to the samples collected in the field, the type specimens of Tongoloa and high-resolution type specimen photos were examined, including the specimens deposited in K, P, E, B, A, GB, LD, MW, NY, GH, W, US, PE, KUN, CDBI, WUK and HNWP. Considering the similarity between the new species and T. silaifolia, as well as other related species, we compared their morphological characteristics. The fresh fruits were preserved with formaldehyde-acetic acid-alcohol (FAA) for anatomical study. The mericarp transverse sections were examined using a stereomicroscope (Nikon SMZ25, Japan) after safranin O-fast green staining.

A plant genomic DNA kit (CWBIO, China) was used to extract total DNA from silica-dried leaves. Referring to the previous studies (White et al. 1990; Zhou et al. 2009), we used nuclear ribosomal DNA internal transcribed spacer (ITS) sequences for phylogenetic inference. Amplification was undertaken using a volume of 30 µl with 15 µl 2 × Taq MasterMix (CWBIO, China), 10 µl ddH2O, 1.5 µl forward primer, 1.5 µl reverse primer and 2 µl total DNA. The PCR reaction was performed in Geneamp PCR System 9700 (USA) with initial denaturation at 95 °C for 2 min, 35 cycles of 94 °C for 60 s, 52.5 °C for 45 s and 72 °C for 60 s and a final extension of 72 °C for 7 min. PCR products were sent to BGI (China) for sequencing. The GenBank accession numbers and sample information of the ITS sequences used in this study are shown in Table 1.

To determine the systematic position of the new species, 37 ITS sequences with accession numbers were obtained from GenBank, including 9 species of Tongoloa (Table 1). Taxa of Chamaesium clade were selected as the outgroup (Downie et al. 2010). Maximum Likelihood (ML) analyses with GTR + G + I model and 1000 bootstrap (BS) replicates was performed using MEGA7 (Kumar et al. 2016). Bayesian Inference (BI) analysis was conducted with MrBayes version 3.2 (Ronquist et al. 2012) and the Markov Chain Monte Carlo (MCMC) search was performed for 1 × 108 generations.

Table 1.

Taxa and voucher information of the used ITS sequences.

Taxon Locality Voucher information GenBank number
Bupleurum chinense China, Anhui, Dabieshan CB Wang 09017 (SZ) GU570615
Bupleurum gibraltaricum Spain, Sevilla S.S. Neves 35 (E) AF479851.1
Bupleurum tenuissimum Portugal, Beira Litoral S.S. Neves 22 (E) AF481932.1
Chamaesium paradoxum China, Sichuan, Daocheng-Litang ZJ0560 (KUN) EU236161.1
Chamaesium thalictrifolium China, Sichuan, Zhangla-Caowan ZJ0607 (KUN) EU236162.1
Chamaesium wolffianum China, Yunnan, Shudu Lake ZJ0525 (KUN) EU236163.1
Changium smyrnioides China, Jiangxi, Jiujiang, Pengze PZ2 (NAS) HQ185254.1
Chuanminshen violaceum China, Sichuan, Cangxi, Xinlong nursery J105 (KUN) FJ385040.1
Cyclorhiza peucedanifolia China, Yunnan, YuLong, Daju, Xiahutiao J034 (KUN) FJ385042.1
Cyclorhiza waltonii China, Sichuan, Derong ZJ0536 (KUN) EU236165.1
Hansenia forbesii China QH6 KJ999463.1
Hansenia oviformis China, Qinghai, Maqin H43 (WNU) MF787544.1
Hansenia weberbaueriana China, Yunnan, KIB nursery ZJ0697 (KUN) EU236180.1
Haplosphaera phaea China, Yunnan, Shudu Lake ZJ0521 (KUN) EU236167.1
Heptaptera anisoptera Iran, Lorestan Pimenov et al. 438 (MW) AY941273.1, AY941301.1
Hymenidium nanum Kirghizstan, Sarydzhas basin Kozhevnikova s.n. (LE) GQ379333.1
Hymenolaena candollei India, Jammu and Kashmir Pimenov and Kljuykov 59 (MW) FJ469958.1, FJ483497.1
Hymenolaena badachschanica Tadjikistan, Badakhshan, Andarob Sultanov 1121 (LE) GQ379332.1
Hymenolaena pimpinellifolia Kirghizia, Kyrgyz Alatoo Pimenov 398 (MW) FJ469959.1, FJ483498.1
Komarovia anisosperma Uzbekistan, Zeravscshtan 178(MW) AF077897.1
Physospermopsis delavayi China, Yunnan, YuLong Snow Mt. J033 (KUN) FJ385056.1
Pleurospermum amabile China, Yunnan, Deqin, Baimaxueshan GLJ19100605 (SZ) MT124614
Pleurospermum franchetianum China, Sichuan YY (WNU) KY848849.1
Pleurospermum uralense China, Liaoning LQX031 (NAS) JF977839.1
Pterocyclus angelicoides China, Xizang G19082501(SZ) MN689078
Pterocyclus rotundatus China G18092501-1 (SZ) MK078059.1
Sinolimprichtia alpina YN China, Yunnan, Deqin, Baimaxueshan GLJ19100702 (SZ) MT124613
S. alpina XZ China, Xizang 0465919 (KUN) FJ385064.1
S. alpina SC China, Sichuan, Yajiang, Jianziwanshan LH2018081402 (SZ) MT124609
Tongoloa arguta YN1 China, Yunnan, Shangri-la, Daxueshan A11 (SZ) MT124619
T. arguta YN2 China, Yunnan, Deqin, Baimaxueshan GLJ18082102 (SZ) MT124599
T. arguta SC1 China, Sichuan, Yajiang, Kazilashan GLJ18092002 (SZ) MT124615
T. arguta SC2 China, Sichuan, Yajiang, Jianziwanshan GLJ19092802 (SZ) MT124612
Tongoloa dunnii China, Hubei, Shennongjia GLJ18091102 (SZ) MT124601
Tongoloa elata China, Sichuan, Songpan, Huangshengguan GLJ19080404 (SZ) MT124607
Tongoloa loloensis China, Yunnan, Eryuan, Baicaoluo GLJ18103002_1 (SZ) MN630615
Tongoloa stewardii China, Fujian, Taining, Huangyanfeng GLJ18090802_2 (SZ) MN630614
Tongoloa silaifolia China, Chongqing, Chengkou JQP19081607_2 (SZ) MT124617
Tongoloa sp. China, Qinghai, Yushu, Jiangxigou GLJ19092201 (SZ) MT124610
Tongoloa taeniophylla China, Sichuan, Kangding, Paomashan GLJ18082902 (SZ) MT124598
Tongoloa tenuifolia China, Yunnan, YuLong Snow Mt. J075 (KUN) FJ385066.1
Trachydium roylei Pakistan, Hazara B. Dickore, 13244 FJ469972.1, FJ483510.1
Trachydium simplicifolium China, Yunnan, Lijiang, Yulongxueshan GLJ19111401 (SZ) MT124618
Trachydium souliei YN1 China, Yunnan, Deqin, Baimaxueshan GLJ18082103 (SZ) MT124603
T. souliei YN2 China, Yunnan, NW part, Degen Co. Pimenov et al. 472 (MW) FJ469973.1, FJ483511.1

Results and discussion

Phylogenetic analysis

The total length of ITS sequence alignment with gaps was 467 bp (without 5.8S rDNA genes). Tongoloa arguta yielded high sequence divergence values with related species, such as T. silaifolia (3.2%–4.0%), T. elata (3.7%–4.6%) and T. taeniophylla (5.0%–5.5%). Analysis of the data using ML and BI methods obtained similar trees with high ML BS and BI posterior probability (PP). Phylogeny reconstruction showed that T. arguta positioned in the Tongoloa clade and different populations of this species formed a strongly-supported monophyletic group (ML BS ≥ 90% and BI PP ≥ 0.90) (Fig. 1).

These results supported T. arguta as an undescribed and distinct species of Tongoloa.

Figure 1. 

Phylogenetic tree of Tongoloa and related groups inferred from ITS based on ML and BI methods. ML BS / BI PP values were shown above the branches. Asterisks (*) denoted strong support (ML BS ≥ 90% and BI PP ≥ 0.90).

Taxonomy treatment

Tongoloa arguta L.J.Gui & X.J.He, sp. nov.

Figs 2, 3, Table 2

Type

China. Sichuan: Kangding, Zheduoshan Pass, 4300 m alt., 30°4'N, 101°48'E, 26 Sep 2019, Lingjian Gui GLJ19092601 (holotype: SZ).

Figure 2. 

Tongoloa arguta sp. nov. A species habitat (Mt. Jianziwanshan, Sichuan, China) B plant in the bush surrounded by snow C plant D–F roots G, H basal leaf, ventral and dorsal view I membranous sheath of basal leaves J middle leaf K upper leaf with membranous petiole L umbel and bract M–O flowers; P–R fruits S mericarp transverse section.

Table 2.

Morphological comparison between Tongoloa arguta and similar species.

Characters T. arguta T. silaifolia T. elata T. gracilis
Height 10–50 cm 28–60 cm 20–75 cm 25–75 cm
Root long-conic conic conic slender
Stem purplish purplish purplish purplish
Lower leaves 2–3-ternate/pinnate, ultimate segments lanceolate, 1–4 mm, apex acute 2–3-ternate/pinnate, ultimate segments linear, 5–18 mm, apex acute 3–4-ternate/pinnate, ultimate segments linear, 5–15 mm 3-ternate/pinnate, ultimate segments linear-lanceolate, 3–15 mm
Bracts often absent, sometimes 1, leaf-like absent absent absent
Bracteoles absent usually absent or 1–5, linear absent absent
Rays 3–8 8–22 6–16 5–11
Petal apex obtuse apex obtuse apex obtuse-rounded apex with incurved tips
Fruit broadly ovoid broadly ovoid broadly ovoid oblong-ellipsoid
Ribs filiform filiform slender filiform

Diagnosis

Tongoloa arguta sp. nov. is morphologically similar to T. silaifolia. However, the new species can be distinguished from the latter by its short stems (10–50 cm), while T. silaifolia has longer ones (28–60 cm); The ultimate segments of the lower leaf of T. arguta are acute and short (1–4 mm), while those of T. silaifolia are linear and longer (5–18 mm). The umbels of T. arguta have 3–8 rays, which are significantly less than those of T. silaifolia (8–22).

Figure 3. 

Tongoloa arguta sp. nov. A habit B root C basal leaf blade D leaf-like bract, only appears in some individuals E flower F fruit G mericarp transverse section. Drawn by Bing-yan Chen.

Description

Plants 10–50 cm. Root usually long-conic. Stem thinly ribbed, glabrous, purplish to green, branched. Leaf sheaths inflated, membranous; blade triangular in outline, 3–5 × 2–3.5 cm, 2–3-ternate/pinnate; ultimate segments lanceolate, 1–4 × 1–2 mm, apex acute. Umbels terminal or lateral; bracts often absent or sometimes 1, leaf-like, ca. 2–4 × 1 cm, bracteoles absent; rays 3–8; umbellules 13–25-flowered. Calyx teeth minute; petals obovate, white to purple, apex obtuse; stylopodium depressed, dark purple; styles short, reflexed. Fruit broadly ovoid, ca. 2 × 1.7 mm, base cordate; ribs 5, filiform; vittae 3 in each furrow, ca. 4 on commissure. Ventral surface of endosperm slightly concave to plane.

Etymology

The species epithet “arguta” was given to describe the acute tips of the ultimate segments of leaves.

Phenology

The species was observed flowering from August to September and fruiting from September to October.

Distribution and habitat

Tongoloa arguta is distributed from Sichuan (Kangding, Yajing) to Yunnan (Deqin, Shangri-la) in south-western China. It grows in alpine bushes and meadows from 4000 m up to 4500 m alt.

Additional specimens examined

China. Sichuan: Kangding, Xinduqiao, Zheduoshan, 4000 m alt., 3 Sep 1982, Taichang Wei 29664 (CDBI0095011); Kangding, north slope of Zheduoshan, 4000 m alt., 22 Sep 1984, Yongjiang Li 454 (CDBI0172327); Yajiang County, Jianziwanshan, 4400 m alt., 28 Sep 2019, Lingjian Gui & Chang Peng GLJ19092802 (SZ); Yajiang County, Kazilashan, 4400 m alt., 20 Sep 2018, Lingjian Gui GLJ18092002 (SZ). Yunnan: Deqin County, Baimaxueshan pass, 4350 m alt., 21 Aug 2018, Lingjian Gui GLJ18082102 (SZ); Shangri-la, Daxueshan pass, 4340 m alt., Yanping Xiao A11 (SZ); Zhongdian, Deqen, Beima Shan, on the south side of road, 4675 m alt., 25 Sep 1994, ACE 1287 (PE00755697).

Conservation status

Tongoloa arguta is common in some alpine bushes and meadows at an altitude of about 4300 m in Yunnan and Sichuan, where human activities and especially yak grazing pose a potential threat to its survival. We categorise T. arguta as Near Threatened (NT), according to IUCN (2019).

Acknowledgements

The authors thank Alexander P. Sukhorukov for his assistance in revising this paper. Thanks to Bing-yan Chen for her drawing and Wei Gou for his assistance in collecting literature. This research was supported by the National Natural Science Foundation of China (Grant No. 31872647), the Chinese Ministry of Science and Technology through the “National Science and Technology Infrastructure Platform” project (Grant No. 2005DKA21403-JK), Sichuan Science and Technology Program (Grant No. 2018TJPT0027) and the fourth national survey of traditional Chinese medicine resources (Grant No. 2019PC002).

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