$¢PhytoKeys PhytoKeys 247: 173-181 (2024) DOI: 10.3897/phytokeys.247.123867 Research Article Spiradiclis yanii (Rubiaceae), a new species from Guangxi, China You Nong™, Li-Qun Lei2®, Gui-Yuan Wei'®, Xin-Cheng Qu™, Zi-Yi Zhao™, Bin Feng'®, Chuan-Gui Xu'®, Lei Wu2® 1 Guangxi Key Laboratory of Traditional Chinese Medicine Quality Standards, Guangxi Institute of Chinese Medicine & Pharmaceutical Science, No. 20-1 Dongge Road, Nanning, Guangxi, China 2 Nanning Botanical Garden; Nanning Qingxiushan Scenic and Historic Tourism Development Co., Ltd, Nanning, Guangxi, China 3 College of Forestry, Central South University of Forestry and Technology, Changsha, Hunan, China Corresponding authors: Chuan-Gui Xu (xuchuangui2021@163.com); Lei Wu (wuleiibk@163.com) OPEN @ ACCESS Academic editor: Andre Simdes Received: 8 April 2024 Accepted: 30 September 2024 Published: 15 October 2024 Citation: Nong Y, Lei L-Q, Wei G-Y, Qu X-C, Zhao Z-Y, Feng B, Xu C-G, Wu L (2024) Spiradiclis yanii (Rubiaceae), a new species from Guangxi, China. PhytoKeys 247: 173-181. https://doi. org/10.3897/phytokeys.247.123867 Copyright: © You Nong et al. This is an open access article distributed under terms of the Creative Commons Attribution License (Attribution 4.0 International - CC BY 4.0). Abstract Spiradiclis yanii Y.Nong & L.Wu (Rubiaceae), a new species from Guangxi, China, is described and illustrated. This new species is most similar to S. tomentosa, but it can be easily distinguished by being densely multicellular villous, leaves narrow elliptic or oblanceolate, apex acute or shortly acuminate, stipules 2-4, linear or linear lanceolate, 4-8 mm, densely villous, corolla tube 3 mm, sparsely pubescent inside, flower homomorphism, lobes 3-5, stamens arising at the base of the tube, stigma 2-lobed, lobes ovoid, slightly swollen, 0.2 mm. The habitat of Spiradiclis yanii is extremely fragile. Therefore, this species deserves close attention and protection. Key words: Longan, limestone, new species, sinkhole, taxonomy Introduction Spiradiclis Blume most closely resembles Ophiorrhiza L. and the two genera are in the same tribe Ophiorrhizeae, based on morphological characters (Verdcourt 1958; Darwin 1976; Lo 1999; Chen and Taylor 2011; Wu et al. 2019) and molec- ular evidence (Bremer 2009; Rydin et al. 2009; Wikstr6m et al. 2013). Robbrecht (1988, 1993) accepted earlier conclusions that Spiradiclis is related to Ophior- rhiza; a more recent study, based on molecular data, suggests that the situation may be more complex and calls into question the separation of these genera (Rydin et al. 2009). Even so, the monophyly of the two genera is questioned (Razafimandimbison and Rydin 2019). However, Spiradiclis is morphologically different from Ophiorrhiza by its linear-oblong or subglobose capsules with four valves (vs. obcordate and compressed capsules with two valves) when mature. Since the delimitation and relationship of the two genera still need further re- search, we prefer to accept the traditional concept of Spiradiclis here due to its unique capsule form. Subsequently, more than 20 new species of Spiradiclis have been discovered in the last decade (e.g. Wang 2016; Zhang et al. 2018; Pan et al. 2019; Tong et al. 2020; Cai et al. 2022). 173 You Nong et al.: Spiradiclis yanii (Rubiaceae), a new species from Guangxi, China During our field surveys in Longan County, Guangxi in March 2024, we found a special Spiradiclis population in flower and fruit that was morphologically similar to the species S. tomentosa D. Fang & D. H. Qin. However, this special population is distinctly different from S. tomentosa, based on being densely multicellular villous, leaves elliptic or oblanceolate, apex acute or shortly acuminate, mid-vein flat adaxially and convex abaxially, stipules 2—4, densely villous. Therefore, we proposed that this special population may represent a new species after we car- ried out more observations and examining many specimens of Spiradiclis from the Herbaria PE, IBK, GXMI and KUN and consulting relevant literature (Lo et al. 1983; Wang 2002; Wang et al. 2015; Wu et al. 2015, 2016, 2019; Pan et al. 2016; Liu et al. 2017; Zhang et al. 2018; Wen et al. 2019; Li et al. 2021; Song et al. 2022). Finally, we carried out one more field survey to confirm that the unusual plant is a species of Spiradiclis new to science and we describe it below. Materials and methods Morphology The new species was described, based on field observations that were made in March 2024 and examination of herbarium specimens at GXMI. Other relat- ed Spiradiclis species were examined, based on online images from the Kew Herbarium Catalogue (http://apps.kew.org/herbcat/gotoHomePage.do) and JSTOR Global Plants (http://plants.jstor.org/) and PE, IBK and KUN. Morpho- logical characters that distinguish it from all other species in the genus of Spi- radiclis are used. We also observed living plants of the new species at flowering and fruiting time (March). We observed characters of stems, leaves, pedicels, flowers, receptacles, petals, stamens, gynoecium, carpels, size of flowers, size and shape of petals, number of stamens and the shape of gynoecium and fruit. Descriptions were written from herbarium specimens. Measurements were made with a tape measure and calipers. The structure of the indumentum and its distribution were observed and described under a dissecting microscope at magni- fications of more than 20x. Additional information on locality, habitat, ecology, plant form and fruits were collected in the field and taken from herbarium labels. The con- servation threat assessment followed IUCN Categories and Criteria (IUCN 2022). Results and discussion Taxonomy Spiradiclis yanii Y.Nong & L.Wu, sp. nov. urn:lsid:ipni.org:inames:77350291-1 Figs 1-4 Chinese name: yan shi luo xt cdo (7 OHA FES) Diagnosis. Spiradiclis yanii is most similar to S. tomentosa, but is different in being densely villous without knots (vs. densely grey-viscid multicellular to- mentose); leaves narrow elliptic or oblanceolate (vs. oblanceolate, obovate or rarely elliptic); apex acute or shortly acuminate (vs. apex cuspidate to rounded); mid-vein flat adaxially and convex abaxially (vs. mid-rib and lateral veins nearly PhytoKeys 247: 173-181 (2024), DOI: 10.3897/phytokeys.247.123867 174 You Nong et al.: Spiradiclis yanii (Rubiaceae), a new species from Guangxi, China ae Figure 1. Habitat of Spiradiclis yanii Y.Nong & L.Wu on cliffs at the bottom of the sinkhole. Photographed by YN. flat on both sides); stipules 2—4, linear or linear lanceolate, 4-8 mm, densely villous (vs. stipules persistent, triangular, 8-22 mm, tomentose); corolla tube 3 mm, sparsely pubescent inside (vs. tube 6-8 mm, glabrous inside); lobes 3-5 (vs. lobes 5); stamens arising at the base of the tube (vs. located at the throat of the corolla); stigma 2-lobed, lobes ovoid, slightly swollen, 0.2 mm (vs. stigma deeply bifid with linear lobes, 1-1.5 mm). At first glance, it also looks similar to S. villosa X. X. Chen & W. L. Sha, but differs by its leaves narrow elliptic or oblan- ceolate, 5-10 x 2-2.5 cm, densely villous adaxially and abaxially (vs. leaves oblong-elliptic or obovate-elliptic, 10-25 x 3-8 cm, adaxially dark brown pubes- cent, abaxially densely brown villous), petiole 0.5—1 cm (vs. petiole 3.5—7 cm), stipules 2-4, linear or linear lanceolate, 4-8 mm, densely villous (vs. stipules 2-lobed, densely dark brown villous, lobes laciniate, 15-30 mm). More detailed morphological differences amongst the three species are shown in Table 1. PhytoKeys 247: 173-181 (2024), DOI: 10.3897/phytokeys.247.123867 175 You Nong et al.: Spiradiclis yanii (Rubiaceae), a new species from Guangxi, China Figure 2. Line drawing of Spiradiclis yanii Y.Nong & L.Wu A flowering branch B flower C ovary and stigma D filaments of stamens and perianth E capsule F seeds G stipules (Drawn by Xin-cheng Qu). Table 1. Main morphological differences amongst Spiradiclis yanii, S. tomentosa and S. villosa. Morphological traits Plant height Stems Leaves Pedicel Stipules Corolla tube Stamens Style and stigma Capsule S. yanii S. tomentosa S. villosa 9-25 em 3=23-6m 30-50 cm densely multicellular villous densely grey-viscid multicellular densely dark brown villous tomentose elliptic or oblanceolate, oblanceolate, obovate or rarely oblong-elliptic or obovate-elliptic, 5-10 x 2-3 cm elliptic, 3.5-14 x 1.5-5 cm TO=25.x3-8'cm 05=1.6m 0.5-4.5 cm eo oe ea 2! 2-4, linear or linear lanceolate, persistent, triangular, 8-22 mm, 2-lobed, lobes laciniate, 15-30 4-8 mm, densely villous tomentose mm. densely dark brown villous 3 mm, sparsely pubescent inside 6-8 mm, glabrous inside Inflorescences and flowers not seen arising at the base of the tube, not | arising at the throat of the corolla, = protruding slightly protruding style 2-3 mm, lobes ovoid, slightly | style 6-7 mm, stigma is deeply > swollen, 0.2 mm bifurcated, lobes linear, 1-1.5 mm obovate, ca. 1 mm subglobose, ca. 2mm ovoid, ca. 2mm Holotype. CHINA » Guangxi: Longan, 23°03'03"N, 107°22'20'E, alt. 327 m, on the cliff at the bottom of a sinkhole, 7 March 2024, Y Nong NY2024030701 (GXMI) (holotype: GXMI!; isotypes: IBK!). Description. Perennial herbs, erect, 5-25 cm tall, stems cylindrical, 1-2 branches, densely multicellular villous when young, but grabrous when old- ‘Leaves opposite, leaf blade drying membranous, narrow elliptic or oblanceolate, PhytoKeys 247: 173-181 (2024), DOI: 10.3897/phytokeys.247.123867 176 You Nong et al.: Spiradiclis yanii (Rubiaceae), a new species from Guangxi, China Figure 3. Spiradiclis yanii Y.Nong & L.Wu A, B plant (flowering and fruiting) C inflorescence (lateral view) D inflorescence (front view, corolla lobes 3-5) E flower (front view) F stamens, ovary and stigma G infructescence (lateral view) H calyx and bracts I capsule J seeds K leaf (adaxially view) L leaf (abaxially view) M, N stipules (Photographed by Ke-Jian Yan & You Nong, edited by You Nong). 5-10 x 2-—2.5 cm, densely multicellular villous adaxially and abaxially, base cu- neate or acute, apex acuminate or shortly acuminate,petiole 0.5-1 cm, dense- ly villous;Mid-vein flat adaxially and convex abaxially,ssecondary veins 9-14 pairs; Stipules 2-4, linear or linear lanceolate, 4-8 mm, densely villous. Inflo- rescence terminal, paniculiform, peduncles 6-15 cm,densely villous,pedicels 3-6 mm,bracts linear, 3-7 mm; Hypanthium portion turbinate, 4 mm, calyx lobes 5, linear or narrow lanceolate, 1.5—2 mm; Flower homomorphism,corolla white, lobes 3-5, ovate, 2-3 mm, outside sparsely pubescent, glabrous inside, tube 3 mm, sparsely pubescent inside; Stamens 5, arising at the base of the tube, not protruding, glabrous, filaments 2 mm, anthers oblong, 0.5 mm; top of the ovary 4-lobed, sparsely pubescent; Ovary 2-loculed, with many ovules, style 2-3 mm, glabrous, stigma 2-lobed, lobes ovoid, slightly swollen, 0.2 mm; PhytoKeys 247: 173-181 (2024), DOI: 10.3897/phytokeys.247.123867 177 You Nong et al.: Spiradiclis yanii (Rubiaceae), a new species from Guangxi, China Faas Figure 4. Digital images of type specimens A Spiradiclis yanii B S. tomentosa C S. villosa. Guizhou Hunan Province Province Yunnan Province ) | : (se Guangxi Zhuang, Autonomous | Guangdong Co! Ux : ol % Iw. Provi a De site rovince ‘ } wm t~‘“‘tsé‘« IF CO FONKIN Se Figure 5. The distribution of Spiradiclis yanii (red circle) in Guangxi, China. Capsule obovate, ca. 1 mm in diam., valves 4, persistent calyx lobes 2-4 mm; Seeds numerous, small and angular. Phenology. Flowering and fruiting in February to March. Etymology. The new species is named after Mr. Ke-Jian Yan, who worked in Guangxi Institute of Chinese Medicine & Pharmaceutical Science and made many contributions to GXMI, especially in Rubiaceae and Lamiaceae. Distribution and habit. Known only from the southeast of Guangxi, China. It has been mainly found on cliffs at the bottom of a sinkhole at elevations of 320 m. PhytoKeys 247: 173-181 (2024), DOI: 10.3897/phytokeys.247.123867 178 You Nong et al.: Spiradiclis yanii (Rubiaceae), a new species from Guangxi, China IUCN red list category. Data available for the new species are still insufficient to assess its conservation status. According to the IUCN Criteria (IUCN 2022), it is considered Data Deficient (DD) until more information becomes available. Although S. yanii currently has relatively good growth, further collection and monitoring are necessary to allow more conclusive estimations about the rarity and vulnerability of the species. Therefore, special attention should be given to the conservation of the new species of Spiradiclis. Additional specimen. Longan * Southeast Guangxi: limestone hills, 7 Novem- ber 2011, J.C. Yang&Y.B. Liao TKO028 (IBK!); Longan, 14 March 2024 Y Nong NY2024031401 (GXMI!). Acknowledgements We are grateful to Xiang-chun Lan for fieldwork assistance and Xin-Cheng Qu for the line drawing (Guangxi Institute of Traditional Medical and Pharmaceuti- cal Sciences, Nanning). Additional information Conflict of interest The authors have declared that no competing interests exist. Ethical statement No ethical statement was reported. Funding This work was supported by the National Natural Science Foundation of China (32000264), the Survey and Collection of Germplasm Resources of Woody & Herba- ceous Plants in Guangxi, China (GXFS-—2021-34). Author contributions Data curation: YN. Funding acquisition: YN, CGX. Investigation: YN, CGX, YGW. Method- ology: YN, LQL, YGW. Project administration: YN, ZYZ. Supervision: BF, LW. Visualisation: YN, LQL. Writing-original draft: YN. Writing-review and editing: YN Author ORCIDs You Nong ® hittps://orcid.org/0000-0001-7004-0946 Li-Qun Lei © https://orcid.org/0009-0009-7319-5439 Gui-Yuan Wei © https://orcid.org/0000-0003-0652-1213 Xin-Cheng Qu © https://orcid.org/0009-0009-9078-9976 Zi-Yi Zhao © https://orcid.org/0000-0003-2513-0728 Bin Feng © https://orcid.org/0000-0003-0387-3635 Chuan-Gui Xu © https://orcid.org/0009-0000-6263-3821 Lei Wu © https://orcid.org/0000-0003-1451-7855 Data availability All of the data that support the findings of this study are available in the main text. PhytoKeys 247: 173-181 (2024), DOI: 10.3897/phytokeys.247.123867 179 You Nong et al.: Spiradiclis yanii (Rubiaceae), a new species from Guangxi, China References Bremer B (2009) A review of molecular phylogenetic studies of Rubiaceae. 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