Abstract
We present a description of a newly discovered species, Primulamedogensis, found in southern Xizang, China. Additionally, we explore distinctive morphological characteristics that aid in its taxonomy. The new species belongs to sect. Cordifoliae and exhibits morphological similarities to P.baileyana and P.rotundifolia. However, it can be distinguished by its densely grayish-haired roots, petioles that are 3–7 times longer than the leaf blades, a short stock surrounded by straight and withered petioles, reniform leaf blades with revolute margins, scapes shorter than or equal to leave and both at flowering and in fruiting, flowers solitary on the scapes.
Key words: Morphological characters, Primula sect. Cordifoliae, taxonomy
Introduction
The genus Primula L. is known for its remarkable complexity within the realm of angiosperm taxonomy. Comprising approximately 500 herbaceous plant species, it predominantly thrives in moderate and cold regions of the Northern Hemisphere; individual species can be found in the mountains of South America and Africa, as well as tropical Asia (Hu 1990, 1994; Hu and Kelso 1996; APG 2016). In China, more than 300 species of the genus are distributed (Richards 2003).
Section Cordifoliae, established by Pax (1889), consists of seven species primarily found in the Eastern Himalayas. These species typically inhabit alpine rocky areas beyond the tree-line on the southern side of the Eastern Himalayas (Richards 2003). The distinguishing characteristics of this section include withered leaves and bud scales at the base, long and slender discrete petioles, and predominantly round leaves with a cordate base.
During botanical explorations in Motuo County, Xizang Province, located in southwest China, we collected a remarkable species of Primula that thrives among mosses, often in crevices on wet cliffs and among boulders. After subsequent examination of herbarium specimens available at CDBI, and careful consultation of literature (Pax 1889; Pax and Knuth 1905; Smith and Forrest 1928; Smith and Fletcher 1943; Hara 1966, 1971; Ohashi 1975; Fenderson 1986; Hu 1986, 1990; Naithani 1990; Fang 1994, 2003; Hu and Kelso 1996; Grierson and Long 1999; Wu 1999; Bista et al. 2001; Sun and Zhou 2002; Kress et al. 2003; Richards 2003; Basak et al. 2014; Xu et al. 2014; Rajbhandari et al. 2021; Li et al. 2023), we identified that this population represents a new species of Primulasect.Cordifoliae by its morphological characters, which is similar to Primulabaileyana Kingdon-Ward and P.gambeliana Watt. In this study, we provide a detailed description of this new species based on observations of living plants in the field and pressed specimens in the herbarium.
Materials and methods
The descriptions and photographs provided in this study were derived from an extensive analysis of the habits and characteristics observed in wild populations during field surveys. Specimens of the new species were collected from the designated type locality and have been stored at CDBI. To supplement our examination, we also accessed digital specimens available online through various platforms, including the Chinese Virtual Herbarium (http://www.cvh.ac.cn/), the JSTOR Global Plants (https://plants.jstor.org/), the Global Biodiversity Information Facility (https://www.gbif.org/), and the Europeana (https://www.europeana.eu), especially type specimens from A, BM, E, K, P, US.
Taxonomic treatment
. Primula medogensis
W.B.Ju, Bo Xu & X.F.Gao sp. nov.
E6473EFC-17B8-50DB-B81B-40D68E99B538
urn:lsid:ipni.org:names:77324820-1
Diagnosis.
This new species is similar to P.baileyana and P.rotundifolia, but it differs from them in having roots with hairs, straight petiole remaining from the previous year, leaf blade reniform and revolute at the margin, petiole more than 3 times the length of the leaf blade, scape equal to or shorter than the leave, flower solitary at the apex of the scape, capsule shorter than the calyx.
Type.
China. Xizang: Motuo City, Duoxiongla, growing in moist rock crevices covered with moss. 31°04'N, 103°11'E, elevation ca. 3607 m, 18 May 2021, W. B. Ju & X. Li YLZB07293 (holotype CDBI!; isotypes KUN!, PE!).
Description.
A perennial plant with a short stock, or up to 2.0 × 1.0 cm, usually girt at the base by the straight and withered petioles. Roots reddish, tuft of wiry, woody on maturity, covered with grayish hairs. Bud scales usually girt at the base by imbricate ovate-oblong to ovate with pale-yellow farinose on the abaxially surface. Leaves including the petiole 1.2–12.5 cm long; leaf blade reniform or suborbicular, but mostly reniform, 0.3–1.5 × 0.4–2.3 cm, firm papery or subleathery, glabrous and with potentially farinose glands above, copious pale-yellow farina on the lower surface, margin dentate revolute on the lower surface, with a deeply cordate to occasionally truncate base, lateral veins 3–4 pairs; petioles 0.9–11.0 cm long, reddish brown, glabrous, slightly broadened and membranous towards the base. Scape 1, sparsely short-stalked glandular, 3.0–10.5 cm tall, erect, hardened in fruiting, usually with a single flower; bracts linear-lanceolate, 0.2–0.5 cm long; pedicels 0.2–1.2 cm long, sparsely short-stalked glandular, not extended in fruit. Flowers heterostylous. Calyx campanulate, 5–8 mm long, glabrous outside, green, inside of pale-yellow farinose, parted nearly to base; lobes lanceolate, margin entire, apex acute, veins 3 with not prominent. Corolla pinkish-purple with a golden-yellow eye, annulate; limb 15–25 mm across, funnelform; lobes spreading, 6–11 × 5–10 mm, broadly obovate, deeply emarginate. Thrum flower: corolla tubes 10–15 mm in length, 2–3 mm in diameter, 2 times the length of calyx, widely ampliated above insertion of stamens; stamens situated at the near apex of the corolla tube; style 3–4 mm. Pin flower: corolla tubes 9–13 mm in length, 2–3 mm in diameter, 2 times the length of calyx; stamens inserted at the middle of corolla tube, style as long as tube. Capsule broad-ovoid to globose, shorter than calyx, dehiscence by apical valves. Seeds numerous, free within capsule at maturity, irregularly ovoid-quadrate or pyriform, ca. 0.5–0.8 mm, brown, testa reticulate.
Phenology.
Flowering occurs in May to June; fruiting at the end of June.
Etymology.
The specific epithet refers to the administrative county name of the type locality viz Motuo (Medog) county in southeast Xizang Autonomous Region, China.
Distribution and habitat.
The new species is currently known only from its type locality in Lage, Motuo (Medog) county, Xizang Autonomous Region. It grows in the cracks of steep wet cliffs covered with moss, at elevations of 3550–3700 m.
Additional specimens examined (Paratypes).
China, Xizang Autonomous Region, Motuo County, Duoxiongla, it grows in the cracks of steep wet cliffs covered with moss, at elevations of 3626 m, 31 May 2015, Bo Xu & X.M.Zhou YLZB01705 (CDBI!).
Conservation status.
Currently, only one population have been found. The size of the Lage population remains unknown. According to the IUCN red list criteria (IUCN 2019), the conservation status of the new species should be better categorized as ‘Data Deficient (DD)’. Further explorations in the adjacent mountainous tracts are necessary for an adequate assessment.
Discussion.
Section Cordifoliae is a small group within the genus Primula that has undergone multiple revisions. Currently, it includes several species such as P.baileyana Kingdon-Ward, P.caveana W.W.Smith, P.gambeliana Watt, P.macklinae A.J.Richards (not validly published), P.littledalei I.B.Balfour & Watt, P.ramzanae Smith & Fletcher and P.rotundifolia Wallich (Richards 2003). These species primarily inhabit the tree-line on mountain rocks of the southern slopes of the Himalayas, at altitudes ranging from 3300 to 6000 meters. The most western species, P.ramzanae, is exclusively found in Phoksumdo Lake in western Nepal. The most eastern species in this section is one incompletely known species P.macklinae, found in northern Myanmar. P.littledalei extends from the southern slopes to Lhasa in the Xizang Autonomous Region, and together with P.baileyana is only found in China. The species represented by P.rotundifolia, P.gambeliana, P.caveana are from central Nepal through Sikkim to Bhutan and Tibet. The distribution area of the new species overlaps with P.baileyana and P.littledalei of this section, which is the lowest elevation distribution except P.macklinae.
Morphologically, P.medogensis shares certain similarities with P.baileyana and P.rotundifolia, both of which also belong to P.sect.Cordifoliae. These similarities include mealy, deciduous plants arising from substantial resting buds, the base of the leaf cluster often has many withered petioles, leaf blades are usually reniform or suborbicular, base cordate, with a conspicuous petiole, corolla pinkish-purple, calyx campanulate, with splitting to below middle, capsule horny (Figs 1–3). However, this new species has a series of morphological characters unique to the section that consists of straight old petioles at the base, petioles 3–7 times longer than the leaf blades, leaf blades mostly reniform with revolute margins, single flowers, and scape shorter than or equal to the leaves. In addition to the unique features described above, P.medogensis clearly differs from P.baileyana by roots clothed in dense grayish hairs, pale- yellow farinose, smaller leaf blades, calyx lobes with 3 veins, and capsules shorter than the calyx; and it differs from P.rotundifolia by its smaller leaf blades, corolla lobes deeply emarginate, the capsule broad-ovoid to globose and shorter than the calyx. For a comprehensive overview of the contrasting characteristics between P.medogensis, P.baileyana, and P.rotundifolia, please refer to Table 1.
Figure 1.
Habitat of the Primulamedogensis sp. nov. (A–D)
Figure 3.
Primulamedogensis sp. nov. A habit B leaves C bud scales D flowers: thrum flower, pin flower, and front of the flower E calyx and ovary F capsule.
Table 1.
Comparison of morphological characters among Primulamedogensis, P.baileyana and P.rotundifolia.
Characters | Primulamedogensis | P.baileyana | P.rotundifolia |
---|---|---|---|
Root | dense grayish hairs | Glabrous | Glabrous |
Stem | straight old petioles at the base | twisted old leaves at the base | twisted old petioles at the base |
Petiole | 3–7 times as long as the leaf blade | 1–3 times as long as the leaf blade | 1–3 times as long as the leaf blade |
Leaf blade | 0.4–2.3 cm wide | 0.5–4.0 cm wide | 4–12 cm wide |
mostly reniform | mostly suborbicular | Suborbicular | |
abaxially pale-yellow farinose | abaxially white farinose | abaxially yellow farinose | |
margin revolute | margin not revolute | margin not revolute | |
Scape | one flower | umbel 1–7 flowered | umbel 2–16 flowered |
shorter than or equal to leaves | 2–3 times as long as leaves | 1.5–2 times as long as leaves | |
Calyx | pale- yellow farinose inside, veins 3 | white farinose inside, veins 5 | yellow farinose inside, veins 3 |
Corolla | lobes deeply emarginate | lobes deeply emarginate | lobes margin entire to obscurely crenulate |
Capsule | broad-ovoid to globose, shorter than calyx | ovoid to oblong, ca. as long as calyx | oblong, longer than calyx |
Figure 2.
Primulamedogensis sp. nov. A fresh plants B pressed specimen C thrum flower D pin flower E leaves F plants base, showing roots, bud scales and petioles G roots covered with greyish hairs H bud scales I capsule J seed.
Supplementary Material
Acknowledgements
We wish to acknowledge Mr. Zhen-long Liang for the line drawing. We want to thank Huai-cheng Li of Freie Universität Berlin for assistance with relevant literature, and Meng Li, Xin-mao Zhou, Yun-dong Gao, Liang Zhang, Xiong Li, Qi Yu, Min Liao, Jun-yi Zhang, Qi Ye, Chen-yu Yang, Yong-ling Qiu, Yan-feng Song for their help during the fieldwork. We are grateful to the staff of A, BM, CDBI, E, FI, HNWP, IBSC, K, KUN, P, PE, US, and WU for providing online access to specimens.
Citation
Ju W-B, Deng H-N, Liu F, He X-J, Gao X-F, Xu B (2023) Primula medogensis, a new species of Primulaceae from Tibet of China. PhytoKeys 230: 107–114. https://doi.org/10.3897/phytokeys.230.107008
Funding Statement
National Key Research and Development Program of China (2020YFE0203200) Wild Plants Sharing and Service Platform of Sichuan Province
Contributor Information
Xin-Fen Gao, Email: xfgao@cib.ac.cn.
Bo Xu, Email: xubo@cib.ac.cn.
Additional information
Conflict of interest
The authors have declared that no competing interests exist.
Ethical statement
No ethical statement was reported.
Funding
This study was supported by the National Key Research and Development Program of China (2020YFE0203200) and Wild Plants Sharing and Service Platform of Sichuan Province.
Author contributions
Conceptualization: BX. Investigation: HND, FL. Methodology: XJH, XFG. Writing - original draft: WBJ.
Author ORCIDs
Wen-Bin Ju https://orcid.org/0000-0002-5665-6290
Heng-Ning Deng https://orcid.org/0000-0002-0581-0649
Xing-Jin He https://orcid.org/0000-0003-2064-0112
Xin-Fen Gao https://orcid.org/0000-0002-5703-1639
Data availability
All of the data that support the findings of this study are available in the main text.
References
- APG [Angiosperm Phylogeny Group] (2016) An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG IV. Botanical Journal of the Linnean Society 181(1): 1–20. 10.1111/boj.12385 [DOI] [Google Scholar]
- Basak SK, Maiti G, Hajra PK. (2014) The Genus Primula L. in India: A Taxonomic Revision. Bishen Singh Mahendra Pal Singh, Dehra Dun, 1–668.
- Bista MS, Adhikari MK, Rajbhandari KR. (2001) Flowering plants of Nepal (Phanerograms). Department of Plant Resources, Kathmandu, Nepal, 1–399.
- Fang RZ. (1994) Primulaceae. In: Wang WT, Wu SG. (Eds) Vascular Plants of the Hengduan Mountains.Science Press, Beijing, 1477–1524.
- Fang RZ. (2003) Primulaceae. In: Institutum Botanicum Kunmingense Academiae Sinicae (Org.) Flora of Yunnanica, Vol. 15. Science Press, Beijing, 326–514.
- Fenderson GK. (1986) A synoptic guide to the genus Primula. Allen press, Lawrence, Kansas, 1–213.
- Grierson AJC, Long DG. (1999) Primula. In: Long DG. (Ed.) Flora of Bhutan, Vol.2(2). Royal Botanic Garden Edinburgh and Royal Government of Bhutan, 516–554.
- Hara H. (1966) The flora of Eastern Himalaya. University of Tokyo Press, Tokyo, 1–754.
- Hara H. (1971) Flora of Eastern Himalaya: Second Report. University of Tokyo Press, Tokyo, 1–393. 10.2307/1219257 [DOI]
- Hu CM. (1986) Primulaceae. In: Wu ZY. (Ed.) Flora Xizangica, Vol.3. Science Press, Beijing, 745–847.
- Hu CM. (1990) Primula. In: Chen FH, Hu CM. (Eds) Flora Reipublicae Popularis Sinicae, Vol.59(2). Science Press, Beijing, 1–277.
- Hu CM. (1994) On the geographical distribution of the Primulaceae. Journal of Tropical and Subtropical Botany 2(4): 1–14. http://jtsb.ijournals.cn/jtsb_cn/article/abstract/199404001?st=article_issue [Google Scholar]
- Hu CM, Kelso S. (1996) Primulaceae. In: Wu ZY, Raven PH. (Eds) Flora of China, Vol.15. Science Press, Beijing & Missouri Botanical Garden Press, St. Louis, 99–185. http://www.iplant.cn/info/Primulaceae?t=foc
- IUCN (2019) Guidelines for Using the IUCN Red List Categories and Criteria, prepared by the Standards and Petitions Committee, version 14. https://www.iucnredlist.org/resources/redlistguidelines
- Kress WJ, DeFilipps RA, Farr E, Kyi DYY. (2003) A Checklist of the Trees, Shrubs, Herbs, and Climbers of Myanmar. United States National Herbarium, Washington, DC: Smithsonian Institution, 1–590.
- Li X, Cheng YH, Lin HQ, Chen C, Gao XF, Deng HN, Feng Y, Andlka PM, Ju WB, Xu B. (2023) Primulawolongensis (Primulaceae), a new species of the primrose from Sichuan, China. PhytoKeys 218: 47–57. 10.3897/phytokeys.218.91161 [DOI] [PMC free article] [PubMed]
- Naithani HB. (1990) Flowering Plants of India, Nepal & Bhutan (not recorded in Sir J.D.Hooker’s Flora of British India). Surya Publications, Dehradun, 1–711.
- Ohashi H. (1975) The Flora of Eastern Himalaya: Third Report. University of Tokyo Press, Tokyo, 1–458.
- Pax FA. (1889) Monographische Übersicht über die Arten der Gattung Primula. Botanische Jahrbücher für Systematik, Pflanzengeschichte und Pflanzengeographie 10(3): 75–241. [Google Scholar]
- Pax FA, Knuth R. (1905) Primulaceae. Das Pflanzenreich: regni vegetablilis conspectus 22: 1–363. [Google Scholar]
- Rajbhandari KR, Rai SK, Chhetri R. (2021) A Handbook of the Flowering Plants of Nepal 3. Department of Plant Resources, Thapathali, Kathmandu, Nepal, 331 pp. [Google Scholar]
- Richards J. (2003) Primula. Timber Press, Portland, Oregon, 1–346.
- Smith WW, Fletcher HR. (1943) The Genus Primula: Section Rotundifolia Balf. Fil. Transactions of the Botanical Society of Edinburgh 33(4): 473–487. 10.1080/13594864309441399 [DOI] [Google Scholar]
- Smith WW, Forrest G. (1928) The Sections of the Genus Primula. Notes from the Royal Botanic Garden Edinburgh 16(76): 1–47. [Google Scholar]
- Sun H, Zhou ZK. (2002) Seed plants of the big bend gorge of Yalu Tsangpo in SE Tibet, Himalayas. Yunnan Science and Technology Press, Kunming, 1–425.
- Wu YT. (1999) Flora Sichuanica, vol. 13. Sichuan Science and Technology Press, Chengdu, 1–288.
- Xu B, Li ZM, Sun H. (2014) Seed plants of the alpine subnival belt from the Hengduan Mountains SW China. Science Press, Beijing, 1–409.
Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Supplementary Materials
Data Availability Statement
All of the data that support the findings of this study are available in the main text.