Research Article |
Corresponding author: Qiang Fan ( fanqiang@mail.sysu.edu.cn ) Academic editor: Clifford Morden
© 2021 Wan-Yi Zhao, Kai-Wen Jiang, Zai-Xiong Chen, Bin Tian, Qiang Fan.
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:
Zhao W-Y, Jiang K-W, Chen Z-X, Tian B, Fan Q (2021) Lespedeza danxiaensis (Fabaceae), a new species from Guangdong, China, based on molecular and morphological data. PhytoKeys 185: 43-53. https://doi.org/10.3897/phytokeys.185.72788
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Lespedeza danxiaensis (Fabaceae), a new species from Danxiashan National Nature Reserve in Guangdong Province, is described and illustrated. The new species is morphologically similar to Lespedeza pilosa, but it can be easily distinguished by its thin leathery leaflets and long peduncles. Phylogenetic analysis based on ITS confirmed that the new species belongs to Lespedeza subg. Macrolespedeza. The new species is the first known species of Lespedeza endemic to Danxia landform and is currently only known from Mount Danxia, Guangdong.
Danxia landform, Guangdong, Leguminosae, new species, taxonomy
Lespedeza Michx. (Fabaceae) is a member of the subtribe Lespedezinae (Hutch.) Schub. of the tribe Desmodieae (Benth.) Hutch. The genus is characterised by shrubs, sub-shrubs or perennial herbs with tri-foliolate leaves (
During a botanical expedition to Danxiashan National Nature Reserve, Renhua County, Guangdong Province from May to October, 2020, we discovered an unknown species of Lespedeza. It is similar to L. pilosa (Thunb.) Siebold & Zucc. in indumentum (densely villous throughout), procumbent stems and ovate to obovate leaflets, but differs from the latter by its leathery leaflets, pinkish corolla and longer peduncles of chasmogamous flowers. After carefully checking specimens and literature, together with a molecular phylogenetic analysis based on Internal Transcribed Spacers (ITS), we demonstrated it is indeed a new species; thus here, we describe and illustrate it.
The morphological characters were examined, based on the living plants and specimens kept in the herbaria IBSC, NPH, SWFC and
Three individuals of L. danxiaensis were collected from Danxiashan National Park, Guangdong province, China from July to September in 2020 (Fig.
The aligned sequences of ITS for phylogenetic analyses are 702 bp in length. Lespedeza was recovered as monophyletic in the resulting phylogenetic tree in this study (LP: 100, Fig.
Phylogenetic relationships amongst 33 species of Lespedeza and Campylotropis macrocarpa based on ITS sequences using Maximum Likelihood analysis, bootstrap value of the Maximum Likelihood (LP) are shown along the branches. The new species described in this study is shown in bold and red type.
A detailed morphological comparisons of the new species with the five closely related species within subclade C-1 are summarized in Table
Morphological comparison of Lespedeza danxiaensis with its closest relatives.
Characters | L. danxiaensis | L. pilosa | L. caraganae | L. cuneata | L. hispida | L. lichiyuniae |
Habit | Procumbent | Procumbent | Erect | Erect or ascending | Erect or ascending | Erect or ascending |
Leaf texture | Leathery or thin leathery | Papery | Papery | Papery | Papery | Papery |
Leaf shape | Ovate, obovate to subrounded | Broadly obovate or obovate | Oblong-linear | Cuneate or linear-cuneate | Narrowly obtriangular or narrowly obovate | Narrowly obovate |
Adaxial surface of leaflet | Pubescent with ± adpressing hairs, more dense along the margin | White ascending-pilose | Subglabrous | Subglabrous | Glabrous | Glabrous |
Abaxial surface of leaflet | Densely pubescent with ± adpressing hairs and more dense along the veins | White ascending-pilose | Adpressed hairy | Densely adpressed hairy | Densely adpressed or ascending pubescent | Densely appressed hairy |
Peduncles of chasmogamous flowers (mm) | (2–) 11–28 | 0.5–1 | 0.5–1 | Short | Ca. 1 | Short |
Flower color | Pink to pale purple | Yellowish white or white | White or yellow | Yellowish or white | White | Pink or pale purple |
China. Guangdong: Renhua County, Danxiashan National Nature Reserve, 24°56'N, 113°45'E, 290 m a.s.l., 30 Sept 2020, Q. Fan 18409 (holotype,
L. danxiaensis is most similar to L. pilosa morphologically both being densely villous throughout, and having procumbent stems with ovate to obovate leaflets, but differs from the latter by its leathery leaflets with obviously concave veins (vs. leaflets papery, veins slightly concave), pink to pale purple corolla (vs. corolla yellowish-white to white, with purple spots at base of the standard) and longer peduncles of chasmogamous flowers (1.1–2.8 cm vs. peduncles of chasmogamous flowers rather short, 0.5–1.0 mm in L. pilosa).
Perennial herbs, evergreen, with densely erect or ascending villous hairs throughout, turn sparse when old. Stems procumbent or ascending, woody at base, 50 cm tall. Leaves alternate, 3-foliolate; stipules persistent, ovate-triangular to triangular-lanceolate, apex acute, 3.5–4.5 mm, with 3–5 veins, sparsely pubescent; petioles 1.4–3.8 cm, densely pubescent; rachis 0.5–1.3 cm, densely pubescent, leaflets leathery, adaxially green, pubescent with ± adpressed hairs, more dense along the margin, abaxially greyish-green, more densely pubescent with ± adpressing hairs and more dense along the veins, lateral veins 8–12 pairs, obviously concave adaxially and prominent abaxially; terminal leaflets slightly larger than lateral ones, ovate to obovate, 2.2–3.8 × 1.5–2.5 cm, obtuse at apex, apiculate, rounded at base; lateral leaflets ovate to sub-rounded, 1.7–3.0 × 1.4–2.3 cm; petiolule ca. 1 mm; the leaves on flowering branches obviously smaller (with rachis 2–5 mm long; terminal leaflets obovate, 1.2–1.8 × 0.8–1.7 cm, apex obtuse or emarginate, broadly cuneate at base, lateral ones rounded to obovate, 0.9–1.5 × 0.7–1.2 cm). Inflorescence a pseudoraceme, 1–2 axillary, with 2–4 flowers per inflorescence, 2-flowered per node; peduncles of chasmogamous flowers slender and pubescent, (0.2–)1.1–2.8 cm, those of cleistogamous flowers reduced to 1–4 mm, on upper part of stems sometimes reduced; bracts 2 per node, narrowly ovate-triangular to broadly triangular, acute at apex, 1.5–3.3 mm, sparsely pubescent adaxially, glabrous abaxially, 3–5-veined. Pedicel 0.5–2.0 mm, pubescent; bracteoles 2, adnate to the base of the calyx, shorter than the calyx tube, oblong-ovate to ovate-lanceolate, 3.5–5.5 mm, sparsely pubescent, 5(–7)-veined. Calyx deeply 5-lobed almost to the base, densely pubescent adaxially, glabrous abaxially; tube ca. 1 mm; lobes lanceolate, sub-equal, 7–8 × ca. 1 mm, acute at apex. Corolla exserted (absent in cleistogamous flowers), pink to pale purple; standard pale purple, with dark purple spots at base, longer than wings and keels, inflexed-auriculate at base, lamina 7.5–8.0 × 6.5–7.0 mm, broadly elliptic to sub-orbicular, apex obtuse or emarginate, attenuate to a claw ca. 1 mm long at base; wings pale purplish-white, slightly shorter than keels, 7.5–8.3 mm with lamina 5.5–6.0 × 2.3–2.6 mm, narrowly ovate, obtuse at apex, slightly auriculate at base, with a basal claw ca. 2.5 mm; keel petals white to pale purplish-white, 7.5–8.5 mm with lamina 5.5–6.0 × 2.8–3.0 mm, obovate to elliptic, obtuse at apex, attenuate to a claw ca. 2.5 mm at base. Stamens glabrous, (9+1) diadelphous, ca. 9 mm, curved upwards in distal part; staminal tubes ca. 5 mm; anthers uniform, ovate, ca. 0.5 mm. Pistils ca. 10 mm, longer than stamens (shorter than stamens in cleistogamous flowers); ovary narrowly elliptic, shortly stipitate, style filamentous, curved upwards in distal part, ascending-pubescent; stigma terminal, capitate. Pods brownish, 1-seeded, elliptic, style persistent at apex, rostrate, 7–9 × ca. 3 mm, densely ascending-pubescent; those of cleistogamous flowers not seen. Seeds ovate, ca. 3.0 × ca. 1.4 mm.
Lespedeza danxiaensis Q. Fan, W.Y. Zhao & K.W. Jiang and L. pilosa (Thunb.) Siebold & Zucc. L. danxiaensis (A–J) A habit, bushwood on the mountaintop of Danxia landform B plant, stems procumbent C adaxial view of leaf, surface green, leather D abaxial view of one leaflet, surface greyish-green with densely pubescent E flowering branchlet with flower bud, stipule triangular-lanceolate, apex acute F front view of flower G lateral view of flower, bracteoles long ovate, sepals narrowly lanceolate H fruiting branchlet, show the long peduncles I fruit, densely pubescent, stamens persistent J flowering branchlet, peduncles usually longer than 1 cm, flower pink to pale purple, young branch reddish brown L. pilosa (K–L) K branchlet with unripe fruit, leaf papery L flowering branchlet, peduncles short, flower white, young branch green. (Photographs: A-J by Qiang Fan K–L by Kai-Wen Jiang).
Flowering from June to October, fruiting from September to December.
The specific epithet refers to Mount Danxia, the locality of the type collection. The Chinese name of the new species is here given as 丹霞铁马鞭 (Dān xiá
tiě mǎ biān), in which “丹霞” is the Chinese name for Mount Danxia, as well as “铁马鞭” being the common name for Lespedeza pilosa and its allies.
Lespedeza danxiaensis is currently known only from a few populations on Mount Danxia in Renhua County, Guangdong Province of China. It was observed to occur in bushwood on the mountaintop of Danxia landform at elevations between 270 and 310 m; plants in association included Osteomeles subrotunda K. Koch, Abelia chinensis R. Br., Lagerstroemia indica L., Selaginella tamariscina (P. Beauv.) Spring etc.
The known localities of Lespedeza danxiaensis are in Danxiashan National Nature Reserve where they are well protected. However, its population size is quite small. There are fewer than 100 individuals surviving in an area of about 200 m2 in the currently known localities. We carried out several field surveys in 2020 from May to October, but no other populations were found. Due to its limited distributional range and small population size, Lespedeza danxiaensis is here recommended as Critically Endangered (CR, B2a) according to IUCN Categories (
Lespedeza danxiaensis Q. Fan, W.Y. Zhao & K.W. Jiang A upper portion of plant B lower portion of plant C chasmogamous flower D cleistogamous flower E staminal tube F pistil G standard H wing-petal I keel-petal J chasmogamous fruit K abaxial view of calyx, flattened L bracts M bracteoles. (Drawn by Rong-En Wu).
China. Guangdong: Renhua County, Danxiashan National Nature Reserve, 24°56'N, 113°45'E, 290 m a.s.l., 3 July 2020, Q. Fan 18027 (IBSC, NPH, SWFC,
It is obvious that the new species belongs to Lespedeza due to its persistent bracts with two flowers inside, non-articulate pedicels, and 1-seeded pods (Fig.
Lespedeza danxiaensis is current only known from the type locality, i.e. Mount Danxia, and only one population with fewer than 100 individuals was found by the authors. They grow in the special habitat of the Danxia landform, confined to the sub-top area of a peak. The special habitat may lead the phenomenon in which the number of this species is extremely small, thus the conservation of the species, including ex situ and in situ conservation, is urgently needed. Lespedeza danxiaensis has a procumbent habit, usually growing in patches on the ground, and is drought-tolerant. Our observations found that the above-ground part of the species survives drought by dropping many leaves during the dry season. Thus, this species may be suitable as a slope protection or soil-and-water conservation plant, which has potential development and application value.
We are deeply grateful to Mrs Rong-En Wu for her excellent illustrations in the manuscript. We thank the curators and staff of herbaria IBSC, NPH, SWFC and
List of the GenBank accession numbers of the ITS sequences of sampled species in this study.
Species | GenBank Accession Number |
---|---|
Campylotropis macrocarpa (Bunge) Rehder | JN402492 |
Lespedeza bicolor Turcz. | JN402403 |
Lespedeza buergeri Miq. | JN402407 |
Lespedeza caraganae Bunge | JN402410 |
Lespedeza chinensis G. Don | JN402415 |
Lespedeza cuneata G. Don | JN402418 |
Lespedeza cyrtobotrya Miq. | JN402422 |
Lespedeza danxiaensis Q. Fan, W. Y. Zhao & K. W. Jiang | MZ468553 MZ468554 MZ468555 |
Lespedeza davidii Franch. | JN402428 |
Lespedeza davurica (Laxm.) Schindl. | JN402425 |
Lespedeza dunnii Schindl. | JN402431 |
Lespedeza fasciculiflora Franch. | JN402452 |
Lespedeza floribunda Bunge | GU572179 |
Lespedeza fordii Schindl. | JN402440 |
Lespedeza formosa (Vogel) Koehne | GU572180 |
Lespedeza forrestii Schindl. | JN402448 |
Lespedeza frutescens (L.) Hornem. | JN402454 |
Lespedeza hengduanshanensis (C.J. Chen) Bo Xu bis, X.F. Gao & Li Bing Zhang | KY174667 |
Lespedeza hirta (L.) Hornem. | JN402449 |
Lespedeza hispida (Franch.) T. Nemoto & H. Ohashi | JN402450 |
Lespedeza homoloba Nakai | JN402451 |
Lespedeza inschanica Schindl. | JN402452 |
Lespedeza japonica L.H. Bailey | GU572186 |
Lespedeza juncea (L. f.) Pers. | JN402457 |
Lespedeza lichiyuniae T. Nemoto, H. Ohashi & T. Itoh | KY174750 |
Lespedeza maritima Nakai | GU572190 |
Lespedeza melanantha Nakai | KY174778 |
Lespedeza nipponica Nakai | GU572193 |
Lespedeza patens Nakai | KY174785 |
Lespedeza pilosa Siebold & Zucc. | KY174795 |
Lespedeza potaninii V.N. Vassil. | KY174804 |
Lespedeza repens W.P.C. Barton | JN402473 |
Lespedeza stuevei Nutt. | JN402474 |
Lespedeza thunbergii (DC.) Nakai | GU572186 |
Lespedeza tomentosa Siebold ex Maxim. | JN402476 |
Lespedeza virgata DC. | JN402481 |
Lespedeza virginica (L.) Britton | JN402483 |