Impatiens maolanensis Zhi-Bin Xiong & Q. Y. Wen 2025, sp. nov.
Creators: name: Li, Bai-Zhu
name: Wen, Qin-Ying
name: Wang, Jin-Dong
name: Huang, Xiao-Xiang
name: Xiong, Zhi-Bin
name: Deng, Zhi-Juan
name: Yi, Yin
name: Tang, Xiao-Xin
Publisher: name: Zenodo
Year: 2025
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Magnoliopsida
Ericales
Balsaminaceae
Impatiens
Impatiens maolanensis

description: Impatiens maolanensis Zhibin Xiong & Qinying Wen sp. nov.
Figs 1, 3 A – D, 4 A – C
Diagnosis.
Impatiens maolanensis is similar to I. auriculata (Figs 2 A – G, 3 E – H, 4 D – F), I. liboensis (Figs 2 H – N, 3 I – L, 4 G – I) and I. tianlinensis (Zeng et al. 2015, 2016) but its characteristics are significantly different from the latter three species in terms of orange-red flowers, thick fibrous root, stem with leaf scars and nodes, petioles, sessile or nearly sessile, bracts, outer lateral sepals, dorsal petal, lower sepal, and fruit color (Table 1).
Type.
China • Guizhou Province, Qiannan Buyei and Miao Autonomous Prefecture (黔南布依族苗族自治州), Libo County (荔波县), Maolan National Nature Reserve (茂兰国家级自然保护区), Karst terrain, 25°19'59"N, 108°2'58"E, alt. 541 m, 28 October 2024, Zhibin Xiong and Qinying Wen (holotype: GZNU 2024102801!, isotypes: GZNU 2024102802!, GZNU 2024102803!).
Etymology.
The specific epithet ‘ maolanensis ’ refers to the locality where this new species was discovered, located in Maolan National Nature Reserve, Libo County, Guizhou Province, China. The new species is named ‘ 茂兰凤仙花’ in Chinese.
Description.
Plants perennial, 25–35 cm tall. Roots fibrous, 0.5 cm thick or thicker, up to 9 cm long. Stem robust, erect, branched, 0.4 cm thick or thicker, with leaf scars and nodes. Leaves alternate, densely arranged at the top of stem, glabrous, deep green, membranous, 9–12.5 cm long, 2.5–4 cm wide; petiole, sessile or nearly sessile, with two glands at base; lamina 10.4–13.6 cm long, 3.1–3.7 cm wide, over-oblong or ovate-lanceolate, acuminate to cuspidate at apex, cuneate at base, with crenate margin, setose between marginal teeth; lateral veins in 6–9 pairs. Inflorescences in upper leaf axils, racemose, 2–4 flowered, peduncle 5–7 cm long, dark green to dark red; pedicels 1–2 cm long, dark red; bract 1, at base or middle of pedicel, persistent, bracts ovate with long-cuspidate apex, 3–5 mm long, dark red. Flowers orange-red, 4–5 cm long. Lateral sepals 4; outer lateral sepals 2, obliquely ovate, 1.5 cm long, 0.7 cm wide, dark red, acute at apex, with abaxial midvein slightly thickened; inner lateral sepals 2, linear-lanceolate, 1.5 cm long, 0.28 cm wide, orange adaxial surface, orange with a red stripe on abaxial surface, recurved at apex. Lower sepal saccate, gradually elongates into an incurved or spiraled spur, 3–4 cm long, with a vertical red stripe on the top and base of surface, 4 cm long (excluding spur); mouth obliquely upwards, 1.2–1.5 cm wide, acute at apex. Dorsal petal oblong, 1.2 cm in diameter, orange, cuneate at base, obtuse and emarginate at apex, with abaxial midvein thickened and a vertical red stripe on both adaxial and abaxial surface. Lateral united petals sessile, orange with red spots, 2 - lobed, 2.3–2.6 cm long; basal lobes, orange, nearly oblong, 1.1 cm long, 0.5 cm wide, obtuse at apex; disal lobes, orange-red spots, obovate-oblong, 2.1 cm long, 0.9 cm wide, obtuse at apex and near middle retuse, with abaxial auricle inflexed, suborbicular. Stamens 5, ca. 5 mm long; filaments linear; anther small, ovate, obtuse at apex. Ovary superior, 4 - carpellate, erect with axile placentation, fusiform, red, ca. 5 mm long; stigma four-lobed, red. Capsule obovate-clavate, with a red beak at apex, deep green to dark red, 1.5–2 cm long, 4 - valved, fleshy. Seeds narrowly elliptical, 4.5 mm long, 2.42 mm wide, black.
Phenology.
Flowering season: September to November. Fruiting season: October to December.
Palynology.
Pollen grains of Impatiens maolanensis, I. auriculata, I. liboensis and I. tianlinensis are three-colpate, with an exine with irregular reticulate ornamentation. Pollen grains of I. maolanensis are triangular-round in polar view and elliptical in equatorial view, with a polar: equatorial ratio of 28.4–32.5: 28.2–32.1 μm. The pollen exine has an irregular and relatively smooth reticulate ornamentation, and under high magnification, granular protrusions can be observed (Fig. 3 A – D). Pollen grains of I. auriculata are nearly triangular in polar view and elliptical in equatorial view, with a polar: equatorial ratio of 27.5–32: 26.3–31.2 μm. The pollen exine has an irregular reticulate ornamentation and holes (Fig. 3 E – H). Pollen grains of I. liboensis, are subellipsoid in polar view and elliptical in equatorial view, with a polar: equatorial ratio of 29.6–32.8: 28.7–32.6 μm. The pollen exine has an irregular reticulate ornamentation and holes (Fig. 3 I – L). Pollen grains of I. tianlinensis are triangular in polar, with a polar: equatorial ratio of 29.62–30.47: 12.68–13.54 μm. The pollen exine has an irregular reticulate ornamentation and holes, and there are hardly any granular protrusions within the mesh under high magnification (Zeng et al. 2015, 2016).
Seed micromorphology.
Seeds of Impatiens maolanensis, narrowly ellipsoid, 4.5 mm long, 2.42 mm wide, black. The seed coat has reticulate ornamentation with slightly sunken meshes, folded base, and granular protrusions within the meshes (Fig. 4 A – C). Seeds of I. auriculata, ellipsoid, 4.22 mm long, 2.71 mm wide, brown. The seed coat has reticulate ornamentation with slightly sunken meshes, folded base, and granular protrusions within the meshes (Fig. 4 D – F). Seeds of I. liboensis, ellipsoid, 3.48 mm long, 1.76 mm wide, brown. The seed coat has reticulate ornamentation with sunken meshes, folded base, and no granular protrusions within the meshes (Fig. 4 G – I).
Habitat and distribution.
Impatiens maolanensis has only been observed within the Maolan National Nature Reserve, Libo County, Qiannan Buyei and Miao Autonomous Prefecture, Guizhou Province, China (Figs 1 A – C, 5). Its uniqueness lies in its growth within a tiankeng (a large, naturally formed pit or depression in the earth’s surface) at an altitude of 541 m, within the typical karst area. To reach this location, one must first pass through a karst cave, descend approximately 100 m to a dried-up underground river, and then continue for about 200 m to reach the tiankeng where the species grows. In terms of ecological coexistence, I. maolanensis grows alongside various plants such as Sphagnum sp., ferns, bamboo, Pilea sp., and I. liboensis.
Conservation status.
Our study documented a single population of 18 mature individuals within Guizhou Province, but no expanded surveys have been conducted in adjacent regions or potential habitats (e. g., karst landscapes in Guangxi or Yunnan). The conservation status of Impatiens maolanensis is currently assessed as Data Deficient (DD) under IUCN Red List Categories and Criteria. While the observed population size suggests potential vulnerability, the lack of comprehensive geographic sampling prevents robust assessment against extinction risk criteria (e. g., CR D).
Similar species.
The new species, I. maolanensis is similar to I. auriculata, I. liboensis and I. tianlinensis in floral morphology. All species have alternate leaves, inflorescences, 4 lateral sepals, superior ovaries, 4 carpels, fusiform or obovate-clavate fruits, and three-colpate pollen grains. Nevertheless, the new species is easily distinguishable. Unlike the latter three species, I. maolanensis has a thick fibrous root; stem robust, with leaf scars and nodes; petioles, sessile or nearly sessile; flowers orange-red; bracts and outer lateral sepals, dark red; inner lateral sepals with a red stripe on abaxial surface; dorsal petal oblong, cuneate at base, obtuse and slightly emarginate at apex, with a red stripe on both the adaxial and abaxial surfaces; disal lobes, obovate-oblong, obtuse at apex and near middle retuse, orange with red spots; lower sepal saccate, gradually elongates into an incurved or spiraled spur, mouth obliquely upwards, and a red stripe on the top and base of surface; stigma red; capsule obovate-clavate, with a red beak at apex. The plant height of I. maolanensis is similar to I. liboensis, but significantly lower than I. auriculata and I. tianlinensis. The pollen grains’ micromorphology of I. maolanensis differ from the latter three species in that the pollen grains are triangular-round in polar view. The pollen exine has an irregular and relatively smooth reticulate ornamentation, and the meshes are almost without holes. The seeds’ micromorphology of I. maolanensis differs from I. liboensis and I. auriculata in that the seeds are black and narrowly ellipsoid. The seed coat has reticulate ornamentation with slightly sunken meshes, folded base, and granular protrusions within the meshes. I. maolanensis, I. liboensis and I. auriculata can be found within the Maolan National Nature Reserve in Libo County (Fig. 5). However, I. maolanensis is only discovered growing in a semi-shaded tiankeng, while I. auriculata grows near water, and I. liboensis grows under forests in shady and damp places or beside ditches. More detailed comparison of the four species is presented in Table 1.
description: Published as part of Li, Bai-Zhu, Wen, Qin-Ying, Wang, Jin-Dong, Huang, Xiao-Xiang, Xiong, Zhi-Bin, Deng, Zhi-Juan, Yi, Yin & Tang, Xiao-Xin, 2025, Impatiens maolanensis (Balsaminaceae), a new species of Impatiens in a tiankeng from Guizhou, China, pp. 189-200 in PhytoKeys 254 on pages 189-200, DOI: 10.3897/phytokeys.254.142981