A new species of Scutellaria (Scutellarioideae, Lamiaceae) from Sichuan Province in southwest China.

Scutellaria wuana, a new species discovered from a xeric valley in Muli County of Sichuan Province in southwest China, is described and illustrated. Morphologically, the new species shares similarities with S. mairei, but can be readily distinguished by a suite of morphological characters including a white-pubescent erect stem, conspicuous leaf petioles, and a yellow corolla with a trapeziform lower-middle lip lobe. The habitat and distribution of S. wuana are also distinctive. The position of the new species within Scutellaria is examined in a phylogenetic context using the nuclear ribosomal internal and external transcribed spacers. Additionally, we examine leaf epidermal and pollen grain micromorphology of the new species and putative relatives.

Introduction

The subfamily Scutellarioideae, as presently circumscribed, consists of five genera and about 380 species: Holmskioldia Retz., Renschia Vatke, Scutellaria L., Tinnea Kotschy ex Hook. f., and Wenchengia C.Y. Wu & S. Chow (Harley et al., 2004; Li et al., 2012; Li et al., 2016). With approximately 360 species (Paton, Suddee & Bongcheewin, 2016), Scutellaria is one of the largest genera within Lamiaceae. Although Scutellaria is primarily distributed in temperate regions and on tropical mountains (Paton, 1990a; Paton, 1990b), the genus can be found in most regions of the world except the Amazon basin, lowland tropical Africa, and Pacific islands (Paton, Suddee & Bongcheewin, 2016). China is perhaps the center of diversity of Scutellaria, with 101 species and 25 varieties reported (Li & Hedge, 1994; Zhou & Guo, 2001; Xiao & Wu, 2003; Hsieh, 2013; Xiang, 2016). Forty-six species and 11 varieties occur in southwest China (Wu & Li, 1977), with 10 taxa endemic to Sichuan (Li, 1992).

Scutellaria species are annual or perennial herbs or subshrubs that have various growth forms and habitats (Epling, 1942). The stems are generally quadrangular and covered with glandular or non-glandular hairs. Leaves are typically simple and polytropic in shape, but taxa within sect. Lupulinaria possess pinnatifid leaves. Flowers are always solitary in the axils of +/−diminished leaves or bracts. The calyx is 2-lipped, and the posterior lip is usually folded to produce a scutellum, which is a unique character of the genus. Based on inflorescence and bract characters, Paton (1990a) divided the genus into two subgenera: subgen. Scutellaria Briquet and subgen. Apeltanthus (Nevski ex Juz.) Juz. The former is characterized by having a one-sided inflorescence and flowers subtended by leaves or leaf-like bracts, while the latter has a four-sided inflorescence, with decussate flowers subtended by cucullate bracts. The subgenus Scutellaria was further divided into five sections (i.e., sect. Scutellaria, sect. Anaspis (Rech.f.) Paton, sect. Perilomia (Kunth) Epling, sect. Salazaria (Torrey) Paton, and sect. Salviifoliae (Boiss.) J.R.Edm.), and the subgenus Apeltanthus consists of two sections, i.e., sect. Apeltanthus and sect. Lupulinaria A. Hamilton. This infrageneric classification proposed by Paton (1990a) is the most comprehensive taxonomic treatment of the genus Scutellaria, but only 13 species from China were included. Thus, it is not possible to employ his divisions for the classification of the genus in China. In the updated edition of Lamiaceae in Flora of China, Li & Hedge (1994) divided Scutellaria (98 spp.) into seven groups on the basis of inflorescence, bract, calyx, and nutlet morphology.

During field trips to Sichuan Province in southwest China in July of 2011 and August of 2015, we encountered a noteworthy Scutellaria population in Muli County. However, we were unable to key our collections according to the descriptions from Flora Sichuanica (Li, 1992), Flora Reipublicae Popularis Sinicae (Wu & Li, 1977) and Flora of China (Li & Hedge, 1994). After carefully examining the specimens, we concluded that this population represents a new species of Scutellaria and henceforth describe and illustrate the new species.

Materials & Methods

The morphological study is based on our field collections and herbarium specimens. Additionally, protologues of all published names in the genus Scutellaria from China and adjacent areasas well as related taxonomic literature (Wu & Li, 1977; Li & Hedge, 1994; Zhou & Guo, 2001; Xiao & Wu, 2003; Hsieh, 2013; Paton, Suddee & Bongcheewin, 2016) were assembled and reviewed. To verify morphological differences among the potential new species and other morphologically similar congeners, herbarium material (including types) from CDBI, E, IBK, IBSC, K, KUN, L, PE, SZ were examined (acronyms follow Thiers, 2016). After careful investigation of specimens, we deemed the potential new species to be most similar to S. mairei H. Lév., which guided us in further morphological comparisons.

Leaf materials for scanning electron microscopy (SEM) and light microcopy (LM) were taken from our collections (C.L. Xiang 1200 and/or E.D. Liu et al. 2902) of the new species and herbarium specimens of S. mairei H. Lév. (M.Fr. Ducloux 6438). Methods for examining leaf epidermal microfeatures of both the new and closely related species followed Xiang et al. (2010). Size measurements of 25 pollen grains were made under a Leica DM2500 light microscope (Leica Microsystems GmbH, Wetzlar, Germany). The pollen samples were prepared for the SEM as described by Xiang et al. (2013).

For the molecular phylogenetic studies, the ingroup consisted of 45 samples (41 taxa) representing the two subgenera defined by Paton (1990a). Holmskioldia sanguinea Retz. and Tinnea rhodesiana S. Moore were used as the outgroup based on our previous studies (Li et al., 2016). Voucher information and GenBank numbers are provided in Table 1.

Table 1

Voucher information for phylogenetic analyses and GenBank accession numbers.

Taxon	Voucher/Herbarium barcode	Location	Genbank accession number
		ITS	ETS
Scutellaria discolor	Xiang CL et al., 438 (KUN)	Yunnan, China	MF193504	MF193550
Scutellaria hainanensis	Jiang L et al., 398 (KUN)	Hainan, China	MF193505	MF193551
Scutellaria yunnanensis var. yunnanensis	Liu Ed et al., 3037 (KUN)	Yunnan, China	MF193506	MF193552
Scutellaria yunnanensis var. cuneata	Xiang CL et al., 574 (KUN)	Yunnan, China	MF193507	MF193553
Scutellaria obtusifolia	Chen YP et al., EM202 (KUN)	Sichuan, China	MF193508	MF193554
Scutellaria sichourensis	Xiang CL et al., 566 (KUN)	Yunnan, China	MF193509	MF193555
Scutellaria wenshanensis	Zhao F et al., 008 (KUN)	Yunnan, China	MF193510	MF193556
Scutellaria yangbiense	Liu ED et al., 2238 (KUN)	Yunnan, China	MF193511	MF193557
Scutellaria calcarata	Shui YM et al., Z-03343396 (KUN)	Yunnan, China	MF193512	MF193558
Scutellaria indica	Peng H, s.n (KUN)	Hongkong, China	MF193513	MF193559
Scutellaria indica fo. parvifolia	Anonymous,554 (KUN)	Shimoda, Japan	MF193514	MF193560
Scutellaria taiwanensis	Liao PC, s.n. (KUN)	Taiwan, China	MF193515	MF193561
Scutellaria mairei	Shui YM et al., 66205 (KUN)	Yunnan, China	MF193516	MF193562
Scutellaria tenax	Peng H et al., 2012-017 (KUN)	Guizhou, China	MF193517	MF193563
Scutellaria tapintzeensis _1	Cai J et al., 15cs11358 (KUN)	Yunnan, China	MF193518	MF193564
Scutellaria tapintzeensis _2	Cai J et al., 15cs11371 (KUN)	Yunnan, China	MF193519	MF193565
Scutellaria teniana	Xiang CL et al., 288 (KUN)	Yunnan, China	MF193520	MF193566
Scutellaria wuana sp. nov.	Xiang CL et al., 1200 (KUN)	Sichuan, China	MF193521	MF193567
Scutellaria tenera	Chen YP et al., EM187 (KUN)	Jiangxi, China	MF193522	MF193568
Scutellaria macrodonta	Zhao F et al., 2015-006 (KUN)	Beijing, China	MF193523	MF193569
Scutellaria likiangensis	Xiang CL et al., 373 (KUN)	Yunnan, China	MF193524	MF193570
Scutellaria baicalensis	Li DZ et al., 0513 (KUN)	Liaoning, China	MF193525	MF193571
Scutellaria viscidula	Zhao F, 2015-009 (KUN)	Hebei, China	MF193526	MF193572
Scutellaria orthocalyx	Xiang CL, 185 (KUN)	Yunnan, China	MF193527	MF193573
Scutellaria subintegra	Chen YP, EM223 (KUN)	Guangxi, China	MF193528	MF193574
Scutellaria axilliflora	Hu GX, H144 (KUN)	Fujian, China	MF193529	MF193575
Scutellaria shweliensis	Zhao F et al., ZF0068 (KUN)	Yunnan, China	MF193530	MF193576
Scutellaria hunanensis	Hu GX, H96 (KUN)	Hunan, China	MF193531	MF193577
Scutellaria franchetiana	Xiang CL, 287 (KUN)	Yunan, China	MF193532	MF193578
Scutellaria sessilifolia	Xiang CLi, 341 (KUN)	Chongqing, China	MF193533	MF193579
Scutellaria sessilifolia	Peng H et al., 117 (KUN)	Sichuan, China	MF193534	MF193580
Scutellaria galericulata	M-14212	Iran	MF193535	MF193581
Scutellaria regeliana	Jiang L, 149 (KUN)	Neimenggu, China	MF193536	MF193582
Scutellaria dependens	Anonymous, 565	Fujinomiya, Japan	MF193537	MF193583
Scutellaria dependens	Anonymous, 316	Fujinomiya, Japan	MF193538	MF193584
Scutellaria barbata	Xiang CL, 282 (KUN)	Beijing, China	MF193539	MF193585
Scutellaria scordifolia	Yu WT et al., 2822 (KUN)	Qinhai, China	MF193540	MF193586
Scutellaria diffusa	Wang ZH, s.n(KUN)	Germany	MF193541	MF193587
Scutellaria kingiana	Zhang JW et al., ZJW-3890 (KUN)	Xizang, China	MF193542	MF193588
Scutellaria nuristanica	M-32142	Iran	–	MF193589
Scutellaria stocksii	M-30348	Iran	MF193543	MF193590
Scutellaria alpina	Liao PC, s.n.	Europe alpine region	MF193544	MF193591
Scutellaria nepetifolia	TUH-27605 (THU)	Iran	MF193545	MF193592
Scutellaria platystegia	TUH-7697(THU)	Iran	MF193546	MF193593
Scutellaria supina	LiuB et al., CPG28095 (PE)	Xinjiang, China	MF193547	MF193594
Holmskioldia sanguinea	Anonymous, 209	Guandong, China	MF193548	MF193595
Tinnea rhodesiana	Gary Stafford, GIS-359 (KUN)	Pietermaritzburg, South Africa	MF193549	MF193596

Total DNA was extracted from 0.3 g of silica-gel-dried leaves or from leaf fragments of herbarium specimens using a modified CTAB protocol by Soltis et al. (1991). The primer pair ITS4 and ITS5 (White et al., 1990) was used to amplify the entire nrITS region, and primers ETS-B from Beardsley & Olmstead (2002) and 18S-IGS from Baldwin & Markos (1998) were used to amplified the ETS region. The PCR reaction mixtures and program follow Chen et al. (2005).

Sequencing reactions were performed with the dideoxy chain termination method running on an ABI PRISM3730 automated sequencer. The same primers described above for PCR were used for the sequencing reactions. Sequences were assembled and edited with SeqMan (DNASTAR, Madison, Wisconsin, USA; Burland, 2000). Initial automated alignments of nrITS and ETS sequences were made using MEGA version7.0 (Kumar, Stecher & Tamura, 2016) and subsequently adjusted manually based on the similarity criterion in PhyDE v.0.997 (http://www.phyde.de/index.html). Gaps were treated as missing data. Finally, the matrices were concatenated in Phyutility v.2.2 (Smith & Dunn, 2008) and phylogenetic analyses conducted using Maximum likelihood (ML) and Bayesian inference (BI) methods. ML analyses were performed using RAxML HPC2 v.8.2.10 (Stamatakis, 2014), on the CIPRES Science Gateway v.3.3 (Miller, Pfeiffer & Schwartz, 2010). A partitioned model (-q) was selected, and 1,000 bootstrap iterations (-# — -N) were conducted, with other parameters using the default settings. BI analyses were implemented using the program MrBayes v.3.2.2 (Ronquist et al., 2012). The best-fit nucleotide substitution model (GTR +I +G) selected by Akaike information criterion (AIC) in Modeltest v.3.7 (Posada & Crandall, 1998). The Markov chain Monte Carlo (MCMC) algorithm was run for 10,000,000 generations with four chains, and trees were sampled every 100 generations. The first 25% of sampled generations were discarded as burnin, and a 50% majority-rule consensus tree was obtained using the remaining trees.

The electronic version of this article in Portable Document Format (PDF) will represent a published work according to the International Code of Nomenclature for algae, fungi, and plants (ICN), and hence the new name contained in the electronic version are effectively published under that Code from the electronic edition alone. Additionally, the new name contained in this work has been issued with identifiers by IPNIand will eventually be made available to the Global Name Index. The IPNI LSIDs can be resolved and the associated information viewed through any standard web browser by appending the LSID contained in this publication to the prefix “http://ipni.org/.” The online version of this work is archived and available from the following digital repositories: PeerJ, PubMed Central and CLOCKSS.

Results

Morphological studies

Microfeatures of the leaf epidermis of the new species (Figs. 1A–1D) and Scutellaria mairei (Figs. 1E–1H) are shown in Fig. 1. Epidermal cells for both species were polygonal to slightly irregular in shape (Figs. 1A, 1E). Leaf surfaces were all hypostomatic, and anomocytic stomata were present in the abaxial epidermis (Figs. 1D, 1H). Glandular and non-glandular trichomes were found. The capitate glandular trichomes can only be found on the abaxial surface in S. wuana (Figs. 1C, 1D), but on both surfaces in S. mairei (Figs. 1E, 1G). The multicellular non-glandular trichomes were present on both surfaces (Figs. 1A, 1C, 1E, 1G), and densely distributed along the midrib and veins on the abaxial surface (Figs. 1B, 1F). The pollen grains of S. wuana (Figs. 2A–2B) and S. mairei (Figs. 2C–2D) are tricolpate, with a circular outline in polar view (Figs. 2A, 2C). The exine sculpturing in both species possess bireticulate perforations (Figs. 2B–2D).

Figure 1

Scanning electron micrographs of leaf epidermis of Scutellaria wuana (A–D), S. mairei (E–H).

(A) Non-glandular trichomes on adaxial surface in S. wuana. (I) Capitate glandular trichomes mixed with non-glandular on adaxial surface in S. mairei. (B, F) Non-glandular trichomes and capitate glandular trichomes distribute along the veins. (C, G) Non-glandular trichomes and capitate glandular trichomes on abaxial surface. (D, H) Stomata on abaxial surface. Scale bars = 100 μm (A, B, E, F, G), 40 μm (C), 20 μm (D, H).

Figure 2

Scanning electron micrographs of pollen grains for Scutellaria wuana (A, B) and S. mairei (C, D).

(A, C) Pollen grain (polar view), (B, D) exine surface. Scale bars = 2 μm (A–C), 1.5 μm (D).

Molecular systematics

The combined nrDNA dataset contained 1,110 positions, of which 332 characters were parsimony-informative characters. The topologies were congruent between the trees obtained in the ML and BI analyses, and thus only the BI topology tree is provided (Fig. 3). In both analyses, the monophyly of the Scutellaria is strongly supported (ML-BS = 100%, BI-PP = 1.00; all values follow this order hereafter) and consists of two main clades (Fig. 3). Clade I (100%, 1.00) comprises three species, Scutellaria galericulata L., S. diffusa Benth., and S. nuristanica Rech.f. Clade II (78%, 0.99) consists of the remaining species and two subclades can be identified. Subclade I (100%, 1.00) contains S. shweliensis W.W. Sm., S. stocksii Boiss., S. alpina L., S. supina L., S. nepetifolia Benth., S. platystegia Juz., S. likiangensis Diels, S. baicalensis Georgi, S. kingiana Prain, S. viscidula Bunge, and S. macrodonta Hand.-Mazz. It is noteworthy that within this subclade, five species from subgen. Apeltanthus formed a clade with moderate support values (65%, 0.91). Subclade II (57%, −) contains the remainder of Scutellaria and is shown as a polytomy. The new species we described here is a member of this subclade, and grouped with S. teniana Hand.-Mazz. S. mairei, and S. tapintzensis C.Y. Wu & H.W. Li., but with weak support.

Figure 3

BI tree inferred from the combined dataset of nrITS and ETS sequences.

With support values (BS/PP) indicated at branches. The outgroup and recognized clades summarized by the right bars.

Taxonomic treatment

Diagnostic morphologcial features of Scutellaria wuana C. L. Xiang & F. Zhao (C.L. Xiang 1200) (Holotype).

(A) Habit. (B) Leaf blade. (C) Calyx. (D) Flower in frontal view. (E) Flower in lateral view. (F) Anther. Drawing by Lin Wang.

Photographs of Scutellaria wuana in the wild.

(A) Plant habitat. (B) Habitat. (C) Stem. (D) Abaxial surface of leaf. (E) Adaxial surface of leaf. (F) Inflorescence in frontal view. (G) Inflorescence in lateral view. (H) Fruiting calyces. Photographs by CL Xiang.

CHINA. Sichuan Province: Muli County, Xiamaidi Village, in rock-crevice in dry and warm valley, elevation 3,080 m, 27°43′11.5″N, 101°14′07.4″E, 25 August 2015, C.L. Xiang 1200 (Holotype KUN!, isotypes PE!, KUN!).

Scutellaria wuana is similar to S. mairei H. Lév. (Léveillé, 1912) but differs by having an erect stem with white pubescent hairs (vs. suberect stem with gray to yellowish hirsute hairs in S. mairei), a leaf petiole 1–1.5 cm long (vs. 1.5–3 mm in S. mairei), a yellow corolla tube with a pink spot on the galea (vs. limp rose corolla in S. mairei), the median lobe of the lower lip trapeziform (vs. broadly ovate in S. mairei), and an arcuate corolla tube base (vs. slightly saccate in S. mairei).

Perennial herb. Rhizome slender and densely fibrous. Stems 20–60 cm tall, erect, densely white pilose, glandular pubsecent on angles, apically few-branched. Leaves papery, lamina triangular to triangular-cordate, 15–38 mm long, 10–15 mm wide, base broadly cuneate to cordate, margin crenate-serrate, apex obtuse, adaxially sparsely pilose (Fig. 1A), abaxially densely white hirtellous; midrib and veins pubescent (Fig. 1B); petiole 1–1.5 cm. One sided racemes terminal or terminal in axillary branches, 8–14 cm long; bracts sessile, rhombic-ovate, 2–5 mm, leaf-like basally, margin glandular puberulent. Pedicel ca. 2.5 mm, densely white glandular puberulent. Calyx ca. 2 mm, elongate to 5 mm in fruit, glandular puberulent outside; scutellum ca. 1 mm, elongate to 3 mm in fruit. Corolla tube yellow with pink spot on galea, 12–15 mm, densely white glandular puberulent outside, glabrous inside; tube zigzag, ca. 1 cm long, base arcuate; throat ca. 6 mm wide; upper lip galeate, lower lip 3-lobed, median lobe trapeziform, apex emarginate, lateral lobes oblong-ovate, ca. 4 mm wide. Nutlets unseen. Fl. Jul–Aug.

Scutellaria wuana is currently only known from Muli County, Sichuan Province, in southwest China. Based on the information from our own collections and herbarium specimens, a distribution map of S. wuana (solid circle) and S. mairei (triangle) is shown in (Fig. 6). Scutellaria wuana is found in vegetation mainly composed of herbaceous and shrub by plants such as Boenninghausenia albiflora (Hook.) Meisn., Campanula colorata Wall., Hypericum monogynum L., Origanum vulgare L., Salvia castanea Diels and Artemisia sp., etc. More fieldwork is needed to further elucidate its habitat and distribution area.

Figure 6

Distribution map of Scutellaria wuana (•) S. mairei (▴) in China.

The epithet of the new species is named in honor of Professor Cheng-Yi Wu (Zheng-Yi Wu; 1916–2013), a prominent botanist from Kunming Institute of Botany, Chinese Academy of Sciences, to honor his great contributions to the knowledge of the family Lamiaceae in China and his significant work on the flora and vegetation of China for over 70 years.

C.L. Xiang & F. Zhao CHINA. Sichuan: Muli Couunty, Xiamaidi Villlage, 26 July 2011, E.D. Liu et al. 2902. (KUN!) (Paratype).

H. Lév. CHINA. Yunnan: Qiaojia County, 1913, E.E. Marie. 510 (K!); 22 July 1909, F. Ducloux 6438 (KUN!); 2 July 2004, H. Wang et al. 03-1469 (KUN!); Luquan County, 4 August 2008, H. Peng 9620 (KUN!).

Discussion

The monophyly of the genus Scutellaria was confirmed in the present study (Fig. 3), as reported by previous molecular phylogenetic studies (Li et al., 2012; Li et al., 2016; Xiang et al., 2013; Chen et al., 2014; Chen et al., 2016). However, the subgenus Scutellaria defined by Paton (1990a) is non-monophyletic with members of the subgenus scattered in various clades. In addition, all the sections and series defined by Wu & Li (1977) and all groups defined by Li & Hedge (1994) are also not monophyletic. The subgenus Apeltanthus circumscribed by Paton (1990a) formed a small subclade and it is probably monophyletic (subclade ‘Apeltanthus’), but only five species were selected in this study, and future studies including more species from different regions are needed to test the monophyly of this subgenus. The taxonomic level and/or circumscription of the subgen. Apeltanthus should be reconsidered, because subclade Apeltanthus is embedded within subgenus Scutellaria. Future studies of morphological characters in concert with molecular data may provide better evidence for relationships among Scutellaria species, and could clarify the infrageneric classification of the genus.

As shown in (Fig. 3), Scutellaria wuana is a member of subgenus Scutellaria. Since Scutellaria wuana typically has a one-sided inflorescence that is composed of secund flowers and leaf-like bracts, it should be placed in the sect. Scutellaria. However, because all the sections are not monophyletic based on our molecular studies, it is unreasonable to place the new species based on this artificial infrageneric classification. Because S. wuana has a zigzag corolla tube and the leaf margin is denticulate to dentate, we speculate that it has a close relationship with the group defined by Li & Hedge (1994) that includes S. mairei, S. tenax W.W. Sm., S. teniana, and S. tapintzenisis. After careful comparison of the specimens of those species in combination with the results from our molecular phylogenetic study, we conclude that S. wuana is most closely related to S. mairei. Morphologically, both species are perennial herbs with slender rhizomes, triangular leaves with denticulate to dentate margins, and a zigzag corolla tube. However, S. wuana can be readily distinguished from S. mariei by several characters. Additionally, the distribution and habitat are different in the two species. Scutellaria wuana is currently only known from Muli County, Sichuan Province, and grow in rock-crevices within a xeric valley, while S. mairei is only found on dry limestone mountains in northeast Yunnan.The external morphology of S. wuana is more or less comparable with S. tenax; both species are perennial herbs and have triangular leaves and a zigzag corolla tube. However, there are several characters that distinguish S. wuana from S. tenax. Detailed comparisons of the morphology, habitat, and distribution of S. wuana, S. tenax and S. mairei are given in Table 2.

Table 2

Comparison of morphology, habitat, and distribution between Scutellaria wuana, S. mairei. and S. tenax.

Characters	S. mairei	S. wuana	S. tenax
Stem	suberect, 16–22 cm tall, with dense yellow long-hirsute hairs	erect, 20–80 cm,tall, densely with white pubescence	erect, ca 60 cm tall, with white pubescence
Lamina	papery, petiole 1.5–3 mm	papery, petiole 1–1.5 cm	membranous, petiole 0.5–1.8 cm
Corolla color	tube white, corolla limb rose	tube yellow, with pink spot in galea	tube base yellow, galea blue
Corolla tube	zigzag, base slightly dilated	zigzag, base arcuate	zigzag, base bent
Middle lobe of lower lip shape	broadly ovate	trapeziform	broadly oblong-ovate
Habitat	dry limestone mountains	valley	streamside, grasslands, thickets, forests
Distribution area	northeast Yunnan	Muli, Southwest Sichuan	North Yunnan & West Sichuan

Relationships between Scutellaria wuana and its allies (i.e., S. teniana, S. mairei and S. tapintzensis) were not fully resolved. These species formed a clade in our analyses (Fig. 3), but received meager support values. Part of the reason is that only two nuclear DNA regions were used for analyses in this study, and we predict that the use of more chloroplast DNA markers and broad phylogenomic sampling will improve the resolution of the phylogeny. Currently, it is difficult to resolve the species relationships for such a large genus. To this end a multi-disciplinary method including molecular systematics, phylogenomics, morphological anatomy, and taxonomy is necessary for future studies.

Click here for additional data file.

Click here for additional data file.

Click here for additional data file.