$¢PhytoKeys PhytoKeys 238: 231-240 (2024) DOI: 10.3897/phytokeys.238.116767 Research Article Ophiorrhiza reflexa (Rubiaceae), a new species from a karst region in Guangxi, China Chao Shang’, Jun Xue’, Yanjie Yang’, Xiaowen Liao™®, Quanru Liu?, Lei Wu" 1 College of Forestry, Central South University of Forestry and Technology, Changsha 410004, China 2 College of Life Sciences, Beijing Normal University, Beijing 100875, Beijing, China Corresponding author: Lei Wu (wuleiibk@163.com) OPEN Qaceess Academic editor: Petra De Block Received: 3 December 2023 Accepted: 13 February 2024 Published: 26 February 2024 Citation: Shang C, Xue J, Yang Y, Liao X, Liu Q, Wu L (2024) Ophiorrhiza reflexa (Rubiaceae), a new species from a karst region in Guangxi, China. PhytoKeys 238: 231-240. https://doi. org/10.3897/phytokeys.238.116767 Copyright: © Chao Shang 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 Ophiorrhiza reflexa, a new species from Guangxi, China, is described and illustrated in this study. It is morphologically similar to O. alatiflora due to the branched inflorescence, distylous flowers and the tubular-funnelform corolla with five longitudinal wings. The new species can be distinguished from O. alatiflora by its erect inflorescence, its smaller and equal-sized calyx lobes 0.5-0.7 mm long, its corolla tubes winged to the middle and the wings straight and its strongly reflexed corolla lobes at anthesis. Ophiorrhiza reflexa is assessed as least concern (LC) according to IUCN Categories and Criteria. Key words: China, new taxon, Ophiorrhiza, Rubiaceae, taxonomy Introduction Ophiorrhiza Linnaeus (1753) is a notably species-rich and taxonomically com- plicated genus in the family Rubiaceae, comprising about 200-300 species (Deb and Mondal 1997; Chen and Taylor 2011; Li 2020) and mainly distributed in tropical and subtropical Asia (Darwin 1976; Lo 1990; Deb and Mondal 1997; Chen and Taylor 2011; Deng and Huang 2012; Hareesh et al. 2015; Wong 2019; Hu et al. 2021; Schanzer and Nabatov 2022; Liu et al. 2023). Species of the genus are annual or perennial herbs and rarely sub-shrubs that can be easily recognised by their obcordate and compressed fruits, which are dehiscent with two valves along a transverse slit at the top (Darwin 1976; Lo 1990; Chen and Taylor 2011; Wu et al. 2019). Though the genus is well-defined by this distinc- tive fruit shape, demarcation of species within the genus is sometimes very difficult due to the high morphological variation (Nakamura et al. 2006, 2007; Duan and Lin 2007, 2009; Wu et al. 2017c) and insufficient knowledge of flow- ers in most species (Hooker 1880; Schanzer 2004; Wu et al. 2017a, b). China is one of the diversification centres of Ophiorrhiza. Approximately 72 species (with 50 endemics) of the genus have been recorded in this country and they are mainly distributed in southern and south-western China, especially in Guangxi Province and Yunnan Province (Chen and Taylor 2011; Huang et al. 2017; Wu et al. 2017a, b, c, 2018; Tu et al. 2018; Duan et al. 2019; Wen et al. 2019; Hu et al. 2021; Liu et al. 2023). 231 Chao Shang et al.: Anew Rubaceae species from a karst region from Guangxi, China During our field survey in Napo County, western Guangxi, in 2013, we col- lected a peculiar population of plants in full blossom. The individuals were first identified as Ophiorrhiza alatiflora H.S.Lo as they shared similar habitats and morphological characters, such as branched inflorescences, distylous flow- ers with tubular-funnelform corollas and a corolla with five longitudinal wings. After revisiting the area including the type locality of O. alatiflora and further examining the specimens, however, these individuals from Napo County can be distinguished from O. alatiflora mainly by their inflorescences which are erect from their earliest developmental stages (vs. drooping when young, then erect), their smaller calyx lobes (0.5-0.7 vs. 0.9-1.8(—2.5) mm long) which are equal in size (vs. usually unequal), the nature of the longitudinal wings on the corol- la tube (wings extending from top to middle and straight vs. wings extending along entire length and obviously undulate) and the strongly reflexed corolla lobes (vs. spreading) at anthesis. Therefore, the specimens are assumed to represent an undescribed new taxon, which is here described. Material and methods Most materials are deposited at the Herbarium of Forest Plants in Central South University of Forestry and Technology (CSFI). Herbarium acronyms fol- low Thiers (2023). Morphological observations of the new species were derived from field observations, as well as a study of dry specimens. The morphologi- cal terms employed here follow Chen and Taylor (2011). The conservation sta- tus of this new species is evaluated, based on field observations in accordance with IUCN Red List guidelines (IUCN 2023). Taxonomic treatment Ophiorrhiza reflexa L.Wu & Q.R.Liu, sp nov. urn:lsid:ipni.org:names:77336995-1 Figs 1, 2 Diagnosis. The new species is most similar to O. alatiflora, but can be distin- guished from the latter by the inflorescences which are erect from the earliest developmental stages (vs. drooping when young, then erect), the small and equally-sized calyx lobes 0.5-0.7 mm long (vs. 0.9-1.8, sometimes to 2.5 mm long and usually unequal), the longitudinal wings on the corolla tube which run to the middle of the tube and are straight (vs. wings running along entire length and obviously undulate) and the strongly reflexed corolla lobes (vs. spreading) at anthesis. Type. CHINA. Guangxi Zhuang Autonomous Region: Napo County, Pingmeng Town, Guijiao Village, growing in limestone areas, under evergreen broad-leaved forests, rare, 23°0'30"N, 105°51'53"E, 1080 m alt., 25 Oct 2013 (fl.), L. Wu, C. Du & S.S. Mo 4031 (holotype: CSFI 080032!; isotypes: BNU! CSFI! IBK!). Description. Perennial herbs or subshrubs, suberect, up to 100 cm tall. Stems terete to slightly compressed, glabrous. Leaves in subequal pairs; petiole 4-6 cm long, smooth; blade thickly papery, adaxially green, abaxially pale green, broadly ovate to elliptic-ovate, 11-17 x 5-8 cm, glabrous on both surfaces, base broadly cuneate to obtuse, apex acuminate or subacute, margin entire; lat- PhytoKeys 238: 231-240 (2024), DOI: 10.3897/phytokeys.238.116767 930 Chao Shang et al.: Anew Rubaceae species from a karst region from Guangxi, China + Seeger g id ie ee RE is Aces ct = alae ita eg Tita <4 ‘Ke a | eo * F k rf ti Wh a UH i ef. daa Bie 2 ee a nee | ke ; lc mM “All eet AS ‘a0 abn oh) BA AG lcm Figure 1. Ophiorrhiza revoluta A flowering branch B stipule C part of inflorescence D longitudinally dissected short-styled flower E longitudinally dissected long-styled flower F capsules. Drawn from the holotype by X.Y. Zeng. eral veins 9-11 on each side of the mid-rib; stipules caducous, triangular ovate, ca. 1.5 mm long, apex obtuse. Cymes terminal, erect from youngest develop- mental stages, many-flowered; peduncle stout, 3-6 cm long, puberulent; bracts PhytoKeys 238: 231-240 (2024), DOI: 10.3897/phytokeys.238.116767 933 Chao Shang et al.: Anew Rubaceae species from a karst region from Guangxi, China linear-lanceolate, 8-19 x 1-3 mm, glabrous on both surfaces, apex acute; ped- icels 1-3 mm long, puberulent. Flowers heterostylous. Calyx densely pilosu- lous to puberulent; hypanthium turbinate, 5-ribbed; lobes 5, equal, 0.5-0.7 mm long, triangular, subglabrous abaxially, with a gland in each sinus. Corolla white or sometimes slightly pink at apex, tubular-funnelform, outside glabrous; tube 1.3-1.5 cm long, outside longitudinally winged from apex to middle, wings straight, ca. 0.8 mm wide; lobes 5, ovate-triangular, ca. 4 x 3 mm, reflexed, in- side densely pubescent, apex acute. Stamens 5; anthers linear, 2.5-3 mm long. Stigma bilobed; ovary 2-celled. Long-styled flowers: inside with a ring of white hairs at the middle of the corolla tube and puberulent from the middle up to the throat; stamens included, positioned near the middle of the corolla tube; style densely pubescent; stigma positioned near corolla throat, lobes ovate-el- liptic, ca. 1.4 mm long. Short-styled flowers: sparsely pubescent at the middle of the corolla tube; stamens reaching slightly beyond corolla throat, not exsert- ed; style included near the middle of the corolla tube, glabrous; stigma lobes lanceolate-elliptic, 2-3 mm long. Capsules rhomboid, ca. 4 x 9 mm, glabrous. Phenology. Flowering from October to January; fruiting from March to June. Distribution and habitat. Ophiorrhiza reflexa grows in moist places under ev- ergreen broad-leaved forests in the limestone region of Napo County, Guangxi, China (Fig. 4). Preliminary conservation status. Three populations of Ophiorrhiza reflexa with more than 1000 individuals at each site have been found during our field in- vestigations. The three sites all belong to Laohutiao Provincial Nature Reserve, which is well-protected and not under threat (Tang et al. 2013). All individuals are distributed in an area of ca. 50 km? (10 x 5 km) and have remained roughly stable for the past 10 years. According to currently available data, O. reflexa is preliminarily assessed as Least Concern (LC) according to IUCN Categories and Criteria (IUCN 2023). Additional specimens examined (paratypes). CHINA. Guangxi Zhuang Au- tonomous Region: Napo County, Baisheng Town, Nongming Village, 1200 m alt., 14 May 2013 (fr.), L. Wu 3706 (BNU! CSFI!); same locality as holotype, 25 Oct 2013 (fl.), L. Wu, C. Du, S.S. Mo 4033 (BNU! CSFI! IBK!); Napo County, Ping- meng Town, Guigan Village, under evergreen broad-leaved forests, 1100 m alt., 7 Jan 2014 (fl.), L- Wu 4173 (BNU! CSFI!); ibid., 10 May 2017 (fr.), L. Wu & Z.J. Wen 5891 (CSFI!). Etymology. The species epithet refers to the reflexed corolla lobes. The Chi- nese name is given as ‘fan-ban-she-gen-cao (Jz HEHE ARB)’. Notes. Ophiorrhiza is a taxonomically difficult genus despite its easy dis- tinction at genus level by the unique fruits. Misidentification or synonymy have become a major problem (Schanzer 2004; Wu et al. 2017c). As mentioned above, the reason is mainly the high morphological variation and insufficient knowledge of important characters, especially flowers (e.g. Ophiorrhiza nigri- cans H.S.Lo was synonymised as O. japonica Blume by Duan and Lin (2007); O. pseudonapoensis L.Wu & Q.R.Liu has been misidentified as O. napoensis H.S. Lo until Liu et al. (2023)). Based on our field investigations of Ophiorrhiza in China and careful stud- ies of relevant literature and specimens, about 88% of the known species are confirmed to be distylous plants. At least 52 species have been observed PhytoKeys 238: 231-240 (2024), DOI: 10.3897/phytokeys.238.116767 034 Chao Shang et al.: Anew Rubaceae species from a karst region from Guangxi, China Figure 2. Ophiorrhiza reflexa A, B habit C stipule D young inflorescence E inflorescence in lateral view F inflorescences in different development stages G bracts from lower part to upper part of inflorescence H leaves | corollas in lateral view J corollas in top view K longitudinally dissected long-styled flower L longitudinally dissected short-styled flower M infructescence. Photos by L. Wu. Scale bars: 3 mm (C); 1 cm (G, J-L); 2 cm (E, F, |, M); 10 cm (H). PhytoKeys 238: 231-240 (2024), DOI: 10.3897/phytokeys.238.116767 235 Chao Shang et al.: Anew Rubaceae species from a karst region from Guangxi, China sf Z PY pe < a Piguet ae AM. ‘ae A 1. 4 WR KARTE + Fe ek ‘ Figure 3. Morphological comparison of Ophiorrhiza alatiflora and O. japonica A-H O. alatiflora A habit B inflorescences in different developmental stages C calyces and corollas in lateral view D corollas in top view E inflorescence F young inflores- cence G longitudinally dissected long-styled flower H longitudinally dissected short-styled flower I-M O. japonica | habit J co- rollas in lateral view K corollas in top view L, M young inflorescence. Photos by L. Wu. Scale bars: 1 cm (C-H, J-M); 2 cm (B). PhytoKeys 238: 231-240 (2024), DOI: 10.3897/phytokeys.238.116767 Chao Shang et al.: Anew Rubaceae species from a karst region from Guangxi, China 102E 107E L12E Guizhou Yunnan Guangxi 20N 100 200 300 km Gi ft 102E 1O7E 112E Figure 4. Geographical distribution of Ophiorrhiza reflexa (red triangle, Napo County) and O. alatiflora (blac triangle, Malipo County). by us with both long- and short-styled flowers in the same population. Meanwhile, we found that the growth pattern of the inflorescence is relatively stable in Chinese Ophiorrhiza species. Nearly half of the Chinese Ophiorrhiza species have inflorescences that are erect from the youngest developmental stages (see Fig. 2D, F), whereas the other half have inflorescences drooping when young, then gradually becoming erect (see Fig. 3B, F). In the study of Ophiorhiza species from the Pacific Islands, Darwin (1976) made similar ob- servations and pointed out that the morphology of the inflorescence was tax- onomically useful. However, until now, inflorescences have not received suf- ficient attention in most of the past studies (Lo 1990, 1999; Deb and Mondal 1997; Chen and Taylor 2011). Ophiorrhiza reflexa is most similar to O. alatiflora, both of them growing in limestone hills under dense monsoon forests. However, the former differs from the latter mainly by its erect (vs. drooping when young, then erect) inflores- cences (Figs 2D, F, 3B, F), 0.5-0.7 mm long and equal calyx lobes (vs. 0.9-1.8, sometimes to 2.5 mm long and unequal, sometimes distinctly, calyx lobes; Figs 2E, K, L, 3C, G, H), strongly reflexed (vs. spreading) corolla lobes at anthesis (Figs 2E, F, K, L, 3C-E, G, H) and corolla outside with straight (vs. obviously undulate) wings from top to middle (vs. along entire length) (Figs 2E, L, 3C, G). Additionally, Ophiorrhiza reflexa is morphologically similar to O. japonica Blume, the most widely distributed Ophiorrhiza species in China. Both of them have ca- ducous stipules, linear-lanceolate bracts, heterostylous flowers and tubular co- rollas with a villous ring positioned near the middle of the corolla tube in long- styled flowers. However, the new species differs from O. japonica by the erect (vs. drooping when young, then erect) and lax (vs. congested or somewhat lax) inflorescences (Figs 2D, F, 31, L, M), the strongly reflexed (vs. spreading) corolla lobes at anthesis (Figs 2E, I-F, 3I-K) and the longitudinally winged corolla with ca. 0.8 (vs. ca. 0.5) mm wide wings (Figs 2L, 3J). Further distinctive character- istics of the three species are shown in Table 1. PhytoKeys 238: 231-240 (2024), DOI: 10.3897/phytokeys.238.116767 997 Chao Shang et al.: Anew Rubaceae species from a karst region from Guangxi, China Table 1. Morphological comparison of Ophiorrhiza reflexa, O. alatiflora and O. japonica. O. reflexa O. alatiflora O. japonica Leaf blade broadly ovate to elliptic-ovate, 11-17 | ovate or oblong-ovate, 5-13 x 2-7 cm, | ovate to narrowly lanceolate, 1-11 x 5-8 cm, base broadly cuneate to base cuneate, apex shortly acuminate x 0.7-3.5 cm, base cuneate to obtuse, apex acuminate or subacute or subacute obtuse, apex acute to acuminate Secondary veins 9-13 pairs 7-12 pairs 4-8 pairs Inflorescence erect from youngest developmental drooping when young, then gradually drooping when young, then stages erect gradually erect Calyx lobes equal, 0.5-0.7 mm long unequal, 0.9-1.8 mm long, sometimes equal, 0.4-1.2 mm long to 2.5 mm long Corolla tubular-funnelform, outside tubular-funnelform , outside tubular-funnelform to funnelform, longitudinally winged from top to longitudinally winged along entire outside longitudinal winged from middle, wings straight, ca. 0.8 mm wide | length, wings undulate, 0.8-1 mm wide | top to middle, wings to 5 mm wide Corolla lobes ovate-triangular, reflexed, ca. 4 x triangular, spreading, ca. 3-3.5 x triangular to ovate, spreading, ca. 3mm 2.9mm 2.9-4 x 2.5-3.5 mm Acknowledgements The authors are grateful to the curators of the Herbaria BNU, CSFI, GXMI, HN, HUNN, IBK, IBSC, IMC, KUN, PE, SN, YUYU, SYS and SZ for their permission to examine specimens and to the curators of K and P for providing images of specimens online. 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