Two new species, one new record, and one new synonym of Aeschynanthus (Gesneriaceae) from China

241 Two new species, one new record, and one new synonym of Aeschynanthus (Gesneriaceae) from China Lie-Wen Lin1,2 , Li-Yan Wang3, Yong-Jie Guo2,4 , Lei Cai1 1 Yunnan Key Laboratory for Integrative Conservation of Plant Species with Extremely Small Populations, State Key Laboratory of Plant Diversity and Specialty Crops, Kunming Institute of Botany, Chinese Academy of Sciences, CN-650201, Kunming, Yunnan, China 2 Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming 650201, Yunnan, China 3 Yingjiang Branch of Yunnan Tongbiguan Provincial Nature Reserve Administration, Yingjiang 676299, Yunnan, China 4 Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, Yunnan, China Corresponding author: Lei Cai ([email protected]) Copyright: © Lie-Wen Lin 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). Research Article Abstract Southwest China is a biodiversity hotspot, with numerous new Gesneriaceae species recently discovered there. Recent reports of new Aeschynanthus taxa and records from western Yunnan and adjacent areas underscore the region’s continued potential for revealing undescribed diversity. Based on field surveys conducted in Yunnan and Xizang, Southwest China, two new species of Aeschynanthus are described: A. succineus Lei Cai & L.W. Lin and A. tongbiguanensis Lei Cai & L.W. Lin. We also report a new national record for China, A. jouyi D.J. Middleton, previously considered endemic to Vietnam. Furthermore, we propose that A. maoi Debta & A. Shenoy should be reduced to synonymy under A. wardii, based on a critical assessment of the literature, field observations of living plants, and examination of herbarium specimens. Descriptions and illustrations of the diagnostic characters are provided for these species, together with information on their types. Key words: Aeschynanthus, Flora of China, new synonym, new taxon Introduction Southwestern China, encompassing the provinces of Yunnan and Xizang (Tibet), lies within the Indo-Burma Biodiversity Hotspot—one of the world’s most biologically significant regions (Brooks et al. 2006; Basnet et al. 2019). As a botanical center, it harbors flora spanning tropical, subtropical, temperate, and alpine zones, making it a critical reservoir of vascular plant diversity (Zhang et al. 2002; Yang et al. 2004). The region also functions as a major biogeographic transition zone, where the Sino-Himalayan, Southeast Asian, and East Asian floras converge. Levels of endemism are exceptionally high, with many species confined to narrow habitats such as limestone karsts, deep river valleys, and montane forests. This ecological and evolutionary complexity has made southwestern China a focal point for botanical research, with Academic editor: Eberhard Fischer Received: 31 July 2025 Accepted: 28 September 2025 Published: 4 November 2025 Citation: Lin L-W, Wang L-Y, Guo Y-J, Cai L (2025) Two new species, one new record, and one new synonym of Aeschynanthus (Gesneriaceae) from China. PhytoKeys 265: 241–255. https://doi.org/10.3897/ phytokeys.265.167339 PhytoKeys 265: 241–255 (2025) DOI: 10.3897/phytokeys.265.167339 242 PhytoKeys 265: 241–255 (2025), DOI: 10.3897/phytokeys.265.167339 Lie-Wen Lin et al.: Two new species, one new record and one new synonym of Aeschynanthus from China numerous new taxa of Gesneriaceae described in recent years. Its rugged topography and diverse hydrothermal conditions generate a wealth of microhabitats, providing ideal environments for the diversification and persistence of Gesneriaceae (e.g., Cai et al. 2019, 2020; Yang et al. 2019; Wang et al. 2022; Qin et al. 2023; Ding et al. 2024). A notable example is the genus Aeschynanthus Jack, a group of evergreen, epiphytic, or lithophytic plants in the family Gesneriaceae. Species of Aeschynanthus typically grow on trees or rocks in moist, shaded forests, thriving under conditions of high humidity. Many are characterized by trailing or pendulous stems with often leathery leaves, and most produce tubular, brightly colored flowers—usually red or orange—adapted for bird pollination. For example, A. acuminatus is primarily pollinated by generalist birds (Chen et al. 2019). Beyond their ecological roles, several species are widely cultivated as ornamental houseplants, and some are also used in traditional folk medicine (Li et al. 2006). The genus comprises roughly 200 species distributed mainly across tropical and subtropical Asia, ranging from the Himalayas and Indochina Peninsula to New Guinea and the Solomon Islands (Wang et al. 1990, 1998; Middleton 2009, 2016). In China, 36 species have been documented (Wen et al. 2023), with more than 30 occurring in the border regions of southwestern China, underscoring the area’s importance as a center of diversity for the genus (Wang et al. 1990, 1998; Li and Wang 2005). In recent years, several new taxa and records of Aeschynanthus have been reported from western Yunnan, southeastern Xizang, and adjacent areas (e.g., Li et al. 2020; Qin et al. 2023; Ding et al. 2024; Debta et al. 2024; Dey et al. 2025), suggesting that this region remains a promising frontier for the discovery of undescribed species. During recent field investigations in the Gaoligong Mountains and adjacent areas along the China–Myanmar border in Yunnan, China, we identified two distinctive species of Aeschynanthus. Comparison with national floras and relevant literature confirmed that these represent previously undescribed taxa, which are detailed below. In addition, based on our collections and field observations in western Yunnan, we propose that the recently published A. maoi should be reduced to synonymy under A. wardii. We also collected the showy species A. jouyi in the karst region of southeastern Yunnan, a taxon previously regarded as endemic to Vietnam. Accordingly, we describe two new species from China, report one new national record, and propose a new synonym under A. wardii. Materials and methods Specimens of Aeschynanthus were collected during extensive field surveys conducted between 2015 and 2025 in various locations in Yunnan, including Gaoligong Mountain National Nature Reserve, Laoshan Provincial Nature Reserve, and Tongbiguan Provincial Nature Reserve. The following descriptions are based on both living collections and type specimens. We also examined material of Aeschynanthus, including digital images of specimens from 15 herbaria (PE, HITBC, KUN, IBSC, GXMG, IBK, GXMI, SZG, WUK, NAS, E, NY, P, K, BM) (Thiers 2025). Type specimens are deposited at KUN (Herbarium of the Kunming Institute of Botany, Chinese Academy of Sciences). 243 PhytoKeys 265: 241–255 (2025), DOI: 10.3897/phytokeys.265.167339 Lie-Wen Lin et al.: Two new species, one new record and one new synonym of Aeschynanthus from China Taxonomic treatment Aeschynanthus succineus Lei Cai & L.W.Lin, sp. nov. urn:lsid:ipni.org:names:77371482-1 Fig. 1 Diagnosis. Aeschynanthus succineus resembles A. sinolongicalyx and A. longicaulis in having pale green vein patterns on the leaves but can be distinguished by having longer tubulate flowers (35–45 mm vs 20.5–31 mm), fused calyx, and pseudoterminal cymes (vs solitary flower in leaf axils in A. sinolongicalyx and A. longicaulis). Most importantly, this new species can be distinguished from others by the dense pale-purple pubescence on the upper part of its style (Table 1). Type. China • Yunnan Province, introduced from southwestern Yunnan (cultivated in Kunming Botanical Garden on 20 June, 2016, introduction code: KBG2017062005), in flower, 22 September 2020, Cai Lei CL2020092201 (Holotype: KUN!; Isotype: KUN! IBK!). Description. Epiphytic sub-shrubs, pendulous and branched. Stem glabrous, green, cylindrical. Leaves opposite; petiole 3–8 mm long, glabrous; leaf blade leathery, ovate or nearly lanceolate, 45–55 × 25–35 mm, weakly dentate at margins, glabrous on both sides, adaxial surface dark green with pale green vein patterns, abaxial surface pale green with pale red patterns. Cymes pseudoterminal, 2–11 flowers; pedicel glabrous, 6–15 mm long; bracts glabrous, 6–12 mm long, lanceolate. Calyx glabrous, greenish yellow to greenish red, 5-lobed, 16–22 × 4–6 mm, narrowly lanceolate, apex acute, margin entire, lobes fused into calyx tube (5–6 mm) at the base. Corolla 35–45 mm long, tubular, strongly oblique mouth, inflated at middle, externally yellow to orange, with 5 dark lines from the middle of corolla tube to the top of the lobes, glabrous or sparsely short-pubescent outside, with long purplish-red villous hairs robust hairs at the base of the corolla tube inside; lobes ca. 7 mm long, orange with purplish red spots at margin, apex rounded. Stamens 4, exserted; staminode ca. 1 mm long; anthers oblong, thecae parallel, pollen bright yellow. Filaments glabrous, cream white at the base, gradually changing to purplish red from the center to the top; anterior filaments 30–35 mm long, posterior filaments 22–28 mm long. Pistil 10– 20 mm long, yellowish green, dense pale-purple pubescence on the upper part; ovary ca. 8 mm long, glabrous. Fruit and seed not observed. Table 1. Morphological comparison of Aeschynanthus succineus sp. nov., A. sinolongicalyx, and A. longicaulis (Wang et al. 1990; Middleton 2009). A. succineus A. sinolongicalyx A. longicaulis Inflorescence cymes pseudoterminal, 2–11 flowers cymes axillary, 1–3 flowers cymes pseudoterminal, 1–3 flowers Corolla 35–45 mm, yellow and orange 24–28 mm, red, yellow at base 20.5–31 mm, yellow-green Calyx 16–22 mm, lobes fused below middle 25–35 mm, 5-lobed from base 8–18 mm, 5-lobed from base Pistil densely pubescent on the upper part sparsely pubescent sparsely pubescent 244 PhytoKeys 265: 241–255 (2025), DOI: 10.3897/phytokeys.265.167339 Lie-Wen Lin et al.: Two new species, one new record and one new synonym of Aeschynanthus from China Figure 1. Aeschynanthus succineus Lei Cai & L.W. Lin, sp. nov. A. Flowering plant; B. Leaf surfaces; C. Flower in side view; D. Flower, abaxial side; E. Opened corolla; F. Calyx, ovary, and pistil; G. Close-up of pistil. Scale bars: 1 cm (photographed by Cai Lei). 245 PhytoKeys 265: 241–255 (2025), DOI: 10.3897/phytokeys.265.167339 Lie-Wen Lin et al.: Two new species, one new record and one new synonym of Aeschynanthus from China Phenology. Flowers from September to October. Distribution and habitat. According to the information provided by the cultivation staff, Aeschynanthus succineus is currently known only from material introduced from southwestern Yunnan and without detailed collected information. At present, this species is growing well on tree trunks in greenhouses of Kunming Botanical Garden. Etymology. This species bears warm-toned flowers ranging from yellow to orange, resembling amber in color. The specific epithet ‘succineus’ (Latin succinum, ‘amber’) reflects this distinctive hue. Vernacular name. 琥珀芒毛苣苔 Hu Po Mang Mao Ju Tai. Notes. This species was described based on cultivated material introduced to a botanical garden, and no wild populations have yet been discovered. Its precise distribution range and population size remain unknown; therefore, its conservation status is assessed as Data Deficient (DD). Aeschynanthus tongbiguanensis Lei Cai & L.W.Lin, sp. nov. urn:lsid:ipni.org:names:77371483-1 Fig. 2 Diagnosis. This new species can be distinguished from Aeschynanthus tubulosus by its much smaller flowers (13–18 mm vs 30–35 mm) and leaves, along with lanuginose new shoots (vs pubescent young stems in A. tubulosus). Additionally, the glandular ovary and pistil, together with the included stamens and stigma of A. tongbiguanensis, are absent in other shrub-like Aeschynanthus species in the region (such as A. buxifolius, A. andersonii, and A. humilis). Moreover, the flower phenology of A. tongbiguanensis does not overlap with these other species (Table 2). Type. China • Yunnan Province, Dehong Dai and Jingpo Autonomous Prefecture, Yingjiang County, Tongbiguan town, Banggetong, 24°36'16.55"N, 97°39'02.74"E, ca. 1298 m, 20 Dec 2024 (fl.), Cai Lei & Wang Li-Yan CL622 (holotype: KUN!; isotypes: KUN! IBK!). Table 2. Morphological comparison of Aeschynanthus tongbiguanensis sp. nov., A. tubulosus, and A. humilis (Wang et al. 1990; Middleton 2009). A. tongbiguanensis A. tubulosus A. humilis Leaf blade oblanceolate to spatulate elliptic to ovate oblanceolate to spatulate Inflorescence cymes pseudoterminal, 1–3-flowered cymes axillary, 1-flowered cymes pseudoterminal, 1–4-flowered Corolla 13–18 mm, outside glandular 30–35 mm, outside glabrous 15–28 mm, outside sparsely puberulent Calyx 6–8 mm, outside glandular 5–9 mm, outside glabrous 1–4.2 mm, outside puberulent Pistil included, glandular exserted, glabrous exserted, puberulent Stamens included, nearly equal exserted, strongly dimorphic exserted, strongly dimorphic Flower phenology Dec–Feb March Sept–Oct 246 PhytoKeys 265: 241–255 (2025), DOI: 10.3897/phytokeys.265.167339 Lie-Wen Lin et al.: Two new species, one new record and one new synonym of Aeschynanthus from China Figure 2. Aeschynanthus tongbiguanensis Lei Cai & L.W. Lin, sp. nov. A. Flowering plant; B. Young shoot; C. Flower in side view; D. Opened corolla; E. Calyx, ovary, and pistil; F. Close-up of pistil. Scale bars: 1 cm (photographed by Cai Lei and Lin Lie Wen). 247 PhytoKeys 265: 241–255 (2025), DOI: 10.3897/phytokeys.265.167339 Lie-Wen Lin et al.: Two new species, one new record and one new synonym of Aeschynanthus from China Description. Epiphytic small shrubs, erect and branched. Young stem green, lanuginose; the second-year branches brown, manicate. Leaves opposite or 3-verticillate; petiole ca. 3 mm long; leaf blade leathery, oblanceolate to spatulate, 7–25 mm × 6–12 mm, weakly dentate at margins, sparsely ciliate, adaxial surface green, abaxial surface pale green, glabrous on both surfaces, lateral veins obscure. Cymes pseudoterminal, 1–3 flowers; pedicel, calyx, abaxial petal surface, ovary, and style are all covered with dark glandular trichomes; pedicel 8–15 mm, greenish yellow with purplish spots; calyx greenish yellow, 6–8 mm, 5-lobed from below middle, narrowly lanceolate, apex acute. Corolla 13–18 mm long, tubular, strongly oblique mouth, inflated at middle, externally red or reddish orange, abaxial surface orange-yellow, entirely glabrous except for sparsely papillae near base, with purplish red spots at margin; lobes ca. 3 mm long, erect, neither reflexed nor spreading, apex rounded. Stamens and stigma included. Stamens 4, staminode ca. 1 mm long; anthers oblong, pollen pale yellow. Filaments nearly equal, glabrous, creamy yellow at the base, gradually changing to purplish red at the top. Pistil ca. 5 mm long, yellowish green; ovary 6–8 mm long. Fruit and seed not observed. Phenology. Flowers from December to February (the following year). Distribution and habitat. At present, Aeschynanthus tongbiguanensis is known only from its type locality in Tongbiguan, Yingjiang County, China, where it grows on tree trunks in evergreen forests at an elevation of ca. 1300 m. Etymology. The specific epithet ‘tongbiguanensis’ refers to the type locality where the new species was found, Tongbiguan Township, Yingjiang County, Yunnan Province, China. Vernacular name. 铜壁关芒毛苣苔 Tong Bi Guan Mang Mao Ju Tai. Notes. Two epiphytic, shrub-like Aeschynanthus species were collected from adjacent sites in Tongbiguan Town, Yunnan Province, China. We confirmed one as the known species Aeschynanthus tubulosus (Fig. 3), while the other represents a previously undescribed species, which we formally describe here as Aeschynanthus tongbiguanensis. Currently, only about a dozen individuals have been observed on a few trees, with the overall population status remaining unclear. Therefore, its conservation status is assessed as Data Deficient (DD). New records to China Aeschynanthus jouyi D.J.Middleton Fig. 4 Aeschynanthus jouyi D.J.Middleton, Edinb. J. Bot. 66 (3): 417. 2009. Type. Vietnam • Lao Cai, Van Ban District, Liem Phu, Hoang Lien Mountain Range, Ta Xa Mountain close to the Nam Qua River, Northern Vietnam First Darwin Expedition, #105 (holotype: E [barcode E00294857]; isotype: P [barcode P00697843]). Distribution and habitat. In China, Aeschynanthus jouyi is found in Malipo County, Yunnan, where it grows on trees in broad-leaved forests at 800– 1000 m near the Sino–Vietnam border. It is also distributed in montane forests of northern Vietnam at 450–1500 m. Vernacular name. 中越芒毛苣苔 Zhong Yue Mang Mao Ju Tai. 248 PhytoKeys 265: 241–255 (2025), DOI: 10.3897/phytokeys.265.167339 Lie-Wen Lin et al.: Two new species, one new record and one new synonym of Aeschynanthus from China Figure 3. Aeschynanthus tubulosus J. Anthony. A. Flowering plant; B. Leaf surfaces; C. Flower in side view; D. Opened corolla; E. Calyx, ovary, and pistil; F. Fruit. Scale bars: 1 cm (photographed by Cai Lei and Lin Lie Wen). 249 PhytoKeys 265: 241–255 (2025), DOI: 10.3897/phytokeys.265.167339 Lie-Wen Lin et al.: Two new species, one new record and one new synonym of Aeschynanthus from China Figure 4. Aeschynanthus jouyi D.J. Middleton. A. Flowering plant; B. Leaf surfaces; C. Flower in front view; D. Flower in side view; E. Opened corolla; F. Calyx, ovary, and pistil. Scale bars: 1 cm (photographed by Cai Lei and Lin Lie Wen).