Research Article |
Corresponding author: Wen-Bin Ju ( juwb@cib.ac.cn ) Corresponding author: Bo Xu ( xubo@cib.ac.cn ) Academic editor: Avelinah Julius
© 2023 Xiong Li, Yue-Hong Cheng, Hong-Qiang Lin, Cheng Chen, Xin-Fen Gao, Heng-Ning Deng, Feng Yu, Plenković-Moraj Anđelka, Wen-Bin Ju, Bo Xu.
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:
Li X, Cheng Y-H, Lin H-Q, Chen C, Gao X-F, Deng H-N, Yu F, Anđelka P-M, Ju W-B, Xu B (2023) Primula wolongensis (Primulaceae), a new species of the primrose from Sichuan, China. PhytoKeys 218: 47-57. https://doi.org/10.3897/phytokeys.218.91161
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This paper describes and illustrates a new species of Primulaceae, Primula wolongensis sp. nov. from Wolong National Nature Reserve in Sichuan Province, China. It is very rare and currently only known from its type locality. The new species belongs to subsection Chartacea of the section Petiolares on account of lacking bud scales at flowering, being efarinose and having distinct petiolate leaves with more or less rounded lamina. The new species can be differentiated from other members of the subsection by leaf blade margin dentate, and leaf veins which are not raised, scape shorter than or equal to pedicels, yellow flowers and location of stamens of the corolla tube at thrum flower. Molecular phylogenetic analysis based on nuclear ribosome internal transcribed spacer (nrITS) demonstrated that P. wolongensis was sister to subgen. Auriculastrum. Primula wolongensis is currently known from a single location in Wolong Town, and its conservation status is assessed as Data Deficient (DD).
Hengduan Mountains, morphological characters, phylogenetic analysis, Primula sect. Petiolares, taxonomy
Primula L. is the most widespread genus in Primulaceae. It contains about 500 species mainly distributed throughout the moister and cooler regions of the northern hemisphere (
In May 2021, an unusual population of Primula was discovered in moss-covered crevices of wet cliffs above the tree-line, in Sichuan Province. After consulting relevant literature (
Morphological description and measurements of Primula wolongensis were based on living plants and dried herbarium specimens. The taxonomic description follows the terminology used by
Except for the newly generated sequence of Primula wolongensis in this study, the sequences of the remaining 62 samples representing nine subgenera of Primula and two outgroups (Androsace integra and A. paxiana) in molecular phylogenetic analysis were retrieved from GenBank. Total DNA was extracted exclusively from silica-gel dried leaves via a Plant DNA Isolation Kit (Cat.No.DE-06111). We used the same primers as
All sequences were processed with Sequencher v4.1.4 (Gene Codes, Ann Arbor, Michigan, USA) and aligned using MAFFT v7.475 (
The molecular phylogenetic tree showed that Primula wolongensis was sister to subgen. Auriculastrum (ML = 95, Fig.
Amongst the Chinese members of subsect. Chartacea, the new species is easily recognized by the following combination of characters: leaf blade margin dentate, leaf veins which are not raised, scape which is shorter or equal with pedicel, corolla yellow and location of stamens of the corolla tube at thrum flower. The new species is morphologically similar to P. arunachalensis Basak & Maiti and P. fenghwaiana C.M.Hu & G.Hao, but can be easily distinguished from P. arunachalensis by its shorter rootstocks, petioles 3–5× as long as leaf blade (versus 1–2× as long as leaf blade), reticulation of veins obscure on both surfaces (versus veins slightly impressed adaxially and conspicuous abaxially), corolla lobes apex emarginate (versus corolla lobes margin denticulate to lacerate), heterostylous (versus homostylous). Compared with P. fenghwaiana, the difference of the new species is the petioles 3–5× as long as the leaf blade (versus ca.2/3 the length of the leaf blade), leaf blade base cordate (versus base broadly cuneate to almost rounded), leaf blade margin irregular dentate (versus margin remotely denticulate), scapes and pedicels sparsely short-stalked glandular (versus densely covered with minute glandular hairs), corollas yellow (versus pink to white), the position of stamens at thrum flower tube on the middle (versus on the apex).
China. Sichuan: Wenchuan City, Wolong National Nature Reserve, growing in moist rock crevices covered with moss. 31°04'N, 103°11'E, elevation ca. 3400 m, 18 May 2021 (fl./fr.), Y.H. Cheng & H.Q. Lin XuBo2771 (holotype CDBI!; isotypes KUN!, PE!). (Figs
A perennial plant, efarinose, having reddish-brown basal bud scales, second-year buds at the base and free from bud scales at flowering time, rootstock extremely short. Roots numerous, fibrous. Leaves forming a loose rosette; young leaf blade often fold, widely ovate to suborbicular at maturity, 1.0–3.5 × 1–2.5 cm, broadly obtuse to rounded at apex, with a cordate base, margin irregular dentate, glabrous on both surfaces, glaucous below, firm papery when dry, lateral veins 3–5 pairs, slightly impressed adaxially, reticulation of veins obscure on both surfaces; petioles 3.0–8.5 cm long, sparsely short-stalked glandular, reddish brown. Scape 1, sparsely short-stalked glandular, 1.8–4.5 cm tall, non-elongating at fruiting time; umbel with 1–3 flowers; bracts linear to linear-lanceolate, 0.7–1.5 cm long; pedicels 1.5–4.5 cm long, densely short-stalked glandular, not extended in fruit. Flowers heterostylous. Calyx green, campanulate, 6–11 mm long, slightly enlarged, poculiform in fruit, short-stalked glandular, parted slightly below middle to 2/3; lobes ovate-lanceolate, margin entire, apex acute. Corolla yellow with short-stalked glandular, annulate; limb 16–25 mm across, funnelform; lobes spreading, 7–12 × 5–10 mm, broadly obovate, emarginate. Thrum flower: corolla tubes 8–12 mm in length, 3–4 mm in diameter, slightly longer than calyx, widely ampliated above insertion of stamens; stamens inserted slightly above the middle of corolla tube; style ca. 4 mm. Pin flower: corolla tubes 7–10 mm in length, ca. 3 mm in diameter, nearly equal to calyx, widely ampliated above insertion of stamens; stamens in the middle of corolla tube, style ca. 2/3 as long as tube. Capsule globose, included in calyx, disintegrating at maturity.
Flowering May-June, fruiting May-August.
The specific epithet refers to the type locality, Wolong National Nature Reserve.
A Chinese name, wo long bao chun (卧龙报春), is suggested here.
The species has so far only been found at its type locality in Wolong Town, Wenchuan county, Sichuan Province. It grows in the cracks of steep wet cliffs covered with moss above the tree-line.
Data Deficient (DD). Currently, only one population with more than 100 individuals has been found in the type locality. According to the guidelines for using the IUCN Red List categories and criteria (
Following
Further morphological analysis shows that the new species is allied with subsect. Chartacea by having glabrous and efarinose plants, at flowering time devoid of basal bud-scales, more or less rounded blades and slender petioles.
Including the newly described here, there are nine species reported so far for this subsection (
Comparison of morphological characters among Primula wolongensis, P. arunachalensis and P. fenghwaiana.
Characters | P. wolongensis | P. arunachalensis | P. fenghwaiana |
---|---|---|---|
Habitat | moss-covered crevices of wet cliffs | on hill slope | secondary evergreen broad-leaved forests |
Rootstock | less than 0.3 cm long | ca. 2 cm long | 1–2 cm long |
Petioles | 3–5× as long as leaf blade | 1–2× as long as leaf blade | ca.2/3 the length of the leaf blade |
Leaf blade | widely ovate to suborbicular | orbicular | broadly elliptic to broadly obovate |
the veins are not raised on both sides | the veins are raised on both sides | the veins are raised on both sides | |
base cordate | base cordate to truncate | base broadly cuneate to almost rounded | |
margin dentate | margin irregularly and shallowly dentate to denticulate | margin remotely denticulate | |
Scapes | 1.8–4.5 cm, sparsely short-stalked glandular | ca. 1.5 cm, glabrous | 0.8–1.2 cm, densely covered with minute glandular hairs |
as long as pedicel | longer than pedicel | shorter than pedicel | |
Calyx | campanulate, poculiform in fruit | campanulate | narrowly campanulate |
Corolla | yellow, heterostylous, annulate | pale yellow, homostylous, exannulate | pink to white, heterostylous, annulate |
lobes emarginate | lobules dentate or lacerate | lobes bilobed, lobules entire or toothed | |
Stamens | inserted on the middle of the corolla tube at thrum flower | inserted on the apex of the corolla tube at thrum flower | inserted on the apex of the corolla tube at thrum flower |
We would like to thank Huaicheng Li of Freie Universität Berlin for assistance with relevant literature. We thank Min Liao and Lisha Jiang of Chengdu Institute of Biology for photographing the new species. We are grateful to the staff of BM, CDBI, E, FI, HNWP, IBSC, K, KUN, P, PE, US, and WU for providing online access to specimens. The study was financially supported by the National Key Research and Development Program of China (2020YFE0203200), Wild Plants Sharing and Service Platform of Sichuan Province, and 2021 Subsidy Projects of Prohibited Developmental Areas from the Transfer Payment of the National Key Ecological Functional Areas.