Impatiens liupanshuiensis X.X.Bai & T.H.Yuan, 2022

Yuan, Tao-Hua, Chen, Yi, Yu, Shuang, Ren, Liu-Yi, Huang, Rong-Xin, Li, Mei-Jun & Bai, Xin-Xiang, 2022, Impatiens liupanshuiensis (Balsaminaceae), a new species from Guizhou, China, PhytoKeys 192, pp. 37-44 : 37

Impatiens liupanshuiensis X.X.Bai & T.H.Yuan sp. nov.

Figs 1 , 2

Type.

China. Guizhou: Liupanshui City, Zhongshan District, Xiaojiucaiping Mountain , 2887 m alt., 26°51'8.76"N, 104°41'33.67"E, 24 Aug 2021, Xin Xiang Bai et al. BXX368 (holotype: GZAC!; isotype: PE!) .

Diagnosis.

This species is similar to Impatiens xanthocephala W.W. Sm. in its yellow flowers, funnelform lower sepal, broadly-dolabriform distal lobes of lateral united petals and extremely small basal lobes, but it can be distinguished by having 2 (vs. 4) lateral sepals with ciliate (vs. entire) margin, dorsal petal recurved (vs. patent), lateral veins 8-10 pairs [vs. 2-3(4) pairs], apex of the distal lobes of the united petals retuse (vs. rounded), margin serrulate (vs. remotely crenate or shallowly undulate), lamina ovate-lanceolate or lanceolate (vs. ovate or ovate-oblong), 5-10.5 × 1.7-2.8 cm (vs. 1-2 × 0.8-1 cm) and lamina margin serrulate (vs. remotely crenate or shallowly undulate).

Description.

Perennial herb, 30-70 cm tall. Stem erect or procumbent basally, branched, upper part brown pubescent. Leaves alternate, petiolate, petioles 0.3-1 cm long. Lamina 5-10.5 × 1.7-2.8 cm, ovate-lanceolate or lanceolate, apex acuminate, base cuneate, with 1-3 pairs of basal glands, margin serrulate, teeth ending in setae, adaxial surface remotely puberulous on veins, abaxial surface glabrous, lateral veins 8-10 pairs. Inflorescences axillary, 2-flowered; peduncles 2-4 cm long, pedicels 1.5-2 cm long, bracteate above middle; bracts persistent, lanceolate, 2-4 mm long, margin denticulate. Flowers yellow, ca. 2 cm deep. Lateral sepals 2, obliquely ovate or ovate, inequilateral, 3-5 mm long, 2-3 mm wide, remotely denticulate on one or both sides, abaxial mid-vein slightly thickened, green, hyaline both sides, apex acuminate, aristate. Lower sepal funnelform, 0.5 cm deep excluding spur, mouth vertical, 0.5-0.9 cm wide, base abruptly contracted into an incurved spur, spur 1-1.5 cm long. Dorsal petal orbicular, 8-10 mm in diam., recurved at anthesis, abaxial mid-vein carinate, with a curved rostrum towards apex, base truncate, apex retuse. Lateral united petals 2-lobed, sessile, 13-18 mm long, basal lobes oblong, extremely small, 1-2 mm wide, distal lobes broadly-dolabriform, 1-1.3 cm long, 0.9-1 cm wide, apex retuse, base with reddish patches; auricle inflexed, small. Stamens 5, filaments linear, anthers obtuse. Ovary erect, fusiform, 5-carpellate. Capsule cylindrical, 1.5-2 cm long, seeds ellipsoid or ovoid, surface with warty protrusions.

Phenology.

This species was observed flowering from July to October and fruiting from September to November.

Distribution.

This species is currently known from only one population in Xiaojiucaiping Mountain, Zhongshan District, Liupanshui City, Guizhou, China. The population is large, with about 3000-3500 individuals.

Ecology.

This species was collected growing in Fargesia spathacea shrubs on the side of the plank road at an elevation of 2730-2887 m in Xiaojiucaiping Mountain, which is the highest mountain in Guizhou. The main associated species were F. spathacea , Impatiens lecomtei , Sorbaria arborea C.K. Schneid. ( Rosaceae ), Pteridium revolutum (Blume) Nakai ( Dennstaedtiaceae ), Hypericum patulum Thunb. ( Hypericaceae ), Eupatorium lindleyanum DC. ( Asteraceae ) and Senecio scandens Buch.-Ham. ex D. Don ( Asteraceae ).

Etymology.

The specific epithet ' Impatiens liupanshuiensis ' refers to the type locality, Liupanshui City, Guizhou, China. The Chinese name is given as “六盘水凤仙花”.

Conservation status.

Impatiens liupanshuiensis is currently known only from its type locality, Zhongshan District, Guizhou, China, where it is distributed in several places with about 3000-3500 individuals known in the population. As Xiaojiucaiping Mountain is a part of the Axilixi Landscape and Famous Scenery, it is an area exposed to significant human disturbance. The conservation status can be evaluated as Vulnerable (VU) C2a(ii), based on the IUCN Red List Categories and Criteria ( IUCN 2019).

Figures

Figure 1. Impatiens liupanshuiensis A habit B population C, D flower in face view E, F flower in lateral view G flower in dorsal view H flower dissected I lateral sepals (remotely denticulate on one or both sides) J leaves K stamens and pistils L different phases of the recurvature of the dorsal sepal M capsules N seeds. Photographs by X. X. Bai.

Figure 2. Impatiens liupanshuiensis A plant B flower in face view C flower in lateral view D lateral sepals E bract F dorsal sepal G lateral united petal H lower sepal I capsule J stamens and pistils. (Drawn by Y. Chen from holotype and corresponding colour photographs).