Impatiens yunlingensis S.X. Yu, Chang Y. Xia & J.H. Yu, 2022

Yu, Jiang-Hong, Zhang, Wen-Di, Qin, Fei, Xia, Chang-Ying, Qin, Ying, An, Ming-Tai, Gadagkar, Sudhindra R. & Yu, Sheng-Xiang, 2022, Impatiens yunlingensis (Balsaminaceae), a new species from Yunnan, China, PhytoKeys 212, pp. 13-27 : 13

Impatiens yunlingensis S.X. Yu, Chang Y. Xia & J.H. Yu sp. nov.

Figs 1 , 2

Diagnosis.

Similar to I. delavayi Franchet, in having coarsely crenate leave margin, bracts in the upper part, ca. 4/5 length of the pedicels, saccate lower sepal with shallowly bifid spur, but differs from I. delavayi with lateral sepals 4 (vs. 2) and lateral united petal basal lobes subtriangular (vs. dolabriform).

Type.

China. Yunnan: Dêqên County, Yunling Township, Yongzhi Village , understory and along river, alt. 1780 m, 28°11'N, 98°49'E, 07 Oct. 2018, Shengxiang Yu, Changying Xia, Xuexue Wu and Xiaxing Liu 9998 (holotype: PE, isotype: IBK) .

Description.

Annual herb, 50-70 cm tall. Stems slender, erect, branched, or simple, glabrous; inferior nodes swollen, glabrous. Leaves alternate; lower and middle leaves petiolate, upper leaves sessile or subsessile; petiole 2-3 cm long, slender, purplish or pale green, glabrous, glandless; leave blade, 5-8 cm long, 3-5 cm wide, broadly ovate or ovate-orbicular, base cordate, apex obtuse, margin coarsely crenate, thinly membranous, glabrous; lateral vein 5-7 pairs; margin coarsely crenate. Lower and middle leaves petiolate; petiole 2-3 cm long, glabrous, purplish, slender; Racemes in upper axils, 2-3-flowered; peduncles 2-4 cm long, slender. Pedicels 1-3 cm long, glabrous, purplish, bracteate below flowers; bracts ovate, in the upper part, ca. 4/5 length of the pedicels, ca. 1 mm wide, 1-3 mm long, acute, persistent. Flowers purplish, large, 2.5-3.5 cm deep. Lateral sepals 4; outer 2 large, 1-1.5 cm long, ca. 1 cm wide, 1-3 mm long, obliquely ovate, inequilateral, apex acute, glabrous, purplish; inner 2 small, 2-4 mm long, 1-1.5 mm wide, oblong, apex acuminate glabrous, purplish or pale green. Lower sepal 2-2.5 cm deep, 1.5-2 mm wide, 2.5-3 cm long, saccate, purplish red, abruptly narrowed into an incurved spur; spur short, ca. 1 cm long, shallowly bifid. Dorsal petal 8-12 mm long, 10-15 mm wide, orbiculate, base truncate, apex rounded, glabrous, purple, midrib thickened. Lateral united petals 2.5-3 cm long, 2-lobed; basal lobes ca. 1 cm long, 5 mm wide, subtriangular, apex obtuse, glabrous, purplish; distal lobes 2.5-3 cm long, 8-12 mm wide, triangular, apex acute glabrous, purplish or buff; auricle inflexed. Stamens 5, anthers obtuse. Capsule linear, 3-4 cm long, five carpels, many seeds per locule. Seeds elliptic-oblong, tuberculate.

Phenology.

Flowering occurs from September to October, fruiting from September to November.

Distribution and ecology.

This species is only known to be found in Dêqên County, Yunnan, China (Fig. 3 ); under evergreen broadleaf forests and along the river; alt. 1780-2500 m.

Conservation status.

Impatiens yunlingensis is only known from the type locality with two middle-sized populations in an area that has been severely disturbed by overgrazing. Based on lack of additional local studies, we consider its status as Data Deficient [DD] ( IUCN 2017). However, since the Hengduan Mountains are characterized by the high diversity of narrow-ranged species, including endemic, threatened, rare, and nationally protected species ( Qin et al. 2017; Sun et al. 2017; Xu et al. 2019), all of which have been considered as a conservation priority for its global biodiversity hotspot and high species richness ( Myers et al. 2000; Brooks et al. 2006; Xu et al. 2019). The conservation status of this apparently rare and narrow-ranged species is of high concern.

Etymology.

The specific epithet ' yunlingensis ' refers to the locality of the type specimen, Yunling Township, Dêqên County, Yunnan, China.

Additional specimen examined.

Paratype. China. Yunnan: Dêqên County, Yunling Township, Shualao Village; hillside and understory, alt. 2500 m, 28°09'N, 98°47'E, 07 Oct. 2018, Shengxiang Yu, Changying Xia, Xuexue Wu and Xiaxing Liu 10002 (PE).

Seed description and palynology.

Seeds of I. yunlingensis are elliptic-oblong, with a size of 2.6 × 1.9 mm, L (long) / W (wide) = 1.37 (Fig. 4 A-C ). The surface is equipped with coarse tubercular ornamentation mostly covered by grain-shaped appendages. While the seeds of I. delavayi are also elliptic-oblong, with a size of 3.5 × 2.3 mm, L (long) / W (wide) = 1.52 (Fig. 4 D-F ), the surface contains coarse tubercular ornamentation glabrous and no grain shaped appendages on the top. Pollen grains of both I. yunlingensis and I. delavayi are tetracolpate, elliptic in polar view, exine with irregular reticulate ornamentation, and granules in lumina. Impatiens yunlingensis pollen size (E1 × E2: length of long equatorial axis × length of short equatorial axis) is 28.05 × 16.67 μm (Fig. 4 G-I ), while it is 27.78 × 17.50 μm (E1 × E2) for I. delavayi (Fig. 4J-L ) (Suppl. material 1: Table S2).

Figures

Figure 1. Impatiens yunlingensis S. X. Yu, Chang Y. Xia & J. H. Yu, sp. nov. A branch with leaves, flowers and capsules B flower, front view C flower, lateral view D outer lateral sepal E inner lateral sepal F lower sepal G dorsal petal H lateral united petals (H 1) basal lobe (H 2) distal lobe I filaments and anthers J capsules (Drawing by Wen-Hong Lin).

Figure 2. A-F Impatiens yunlingensis A habitat B plant C branch with flower D flower, front view E flower, lateral view F flower anatomy (a) dorsal petal (b) lateral united petals (c) outer lateral sepal (d) inner lateral sepal (e) lower sepal (f) filaments and anthers G Impatiens delavayi branch with flowers H Impatiens delavayi flower.

Figure 3. Geographical distribution of Impatiens yunlingensis.

Figure 4. Scanning electron microscope images of seeds and pollen grains A-C seeds of Impatiens yunlingensis D-F seeds of I. delavayi G-I pollen grains of I. yunlingensis J-L pollen grains of I. delavayi.