Impatiens chenmoui Zheng W. Wang, Xiao C. Li & Q.Wang ter, 2022

Wang, Zheng-wei, Wang, Qi, Xu, Ru-hua, Zhang, Yu & Li, Xiao-chen, 2022, Impatiens chenmoui (Balsaminaceae), a new species from southern Yunnan, China, PhytoKeys 214, pp. 83-95 : 83

Impatiens chenmoui Zheng W. Wang, Xiao C. Li & Q.Wang ter sp. nov.

Figs 2 , 3 , Appendix 2

Type.

China. Yunnan province, Mengla county (勐腊县) Xiangming Yi nationality township (象明彝族自治乡) Kongming Mountain (孔明山) alt. 1639m, 22°8'9.73"N, 101°8'48.86"E, 23 November 2021, Zhengwei Wang and Xiaochen Li, WZW04250 (Holotype: CSH0189505, CSH!; isotypes: CSH0192380, ZJFC!; CSH0189507, HZU!; CSH0189506, JJF!) .

Diagnosis.

Impatiens chenmoui is most similar to I. oblongata Ruchis. & Niet, but is distinguished by the glabrous dorsal petal, pedicel, and bracts, longer pedicel and spur, and fewer lateral sepals (Table 1 ).

Description.

Herb annual. Stem erect, fleshy, glabrous, 12-35 cm tall. Leaves alternate, petioles 1-5 cm, leaf blade 9.5-2.5 × 1.6-3.5 cm, narrowly elliptic or oblong-lanceolate, apex acuminate or long acuminate, base cuneate, margin roughly crenate; adaxially dark green, pilose along veins, abaxially gray-green, glabrous, lateral veins 7-9 pairs. Inflorescences in upper leaf axils, 1-flowered. Pedicels green, glabrous, 2.5 -2.7 cm long. Bracts linear, persistent, 2-3 mm long. Flowers solitary, axillary, pink, or lavender, with pair of darker pink and yellow dots at the base. Lateral sepals 2, inversely coiled, glabrous, green, 2 mm long. Lower sepal funnelform, 3-4 × 2-3mm long, 2-3mm in depth, eaves navicular, base gradually constricted into a spur, variable, usually1.4-1.7 cm long, rarely absent, mouth oblique, ca. 5mm wide, with ca. 2 mm long narrowly triangular tip. Dorsal petal circular, pink or mauve, 5-6 × 4-5mm, apex acuminate, glabrous, ca. 2mm long. United lateral petals sessile, 2-lobed, 6-8mm long. Upper petal large, obovate, 6-7 × 2-5mm, apex often concave. Lower petal small, axe-shaped, 7-8 × 1-3mm, apex rounded, without auriculus at back. Stamens 5, filaments linear, subulate, pale pink, ca. 2-3mm long, distally enlarged, anthers obtuse. Ovary fusiform, 5-carpellate, purple, 2-3 mm long, dorsal suture ridges with trichome. Capsule short fusiform, 12-18mm long, 4-5 mm in diam, with trichome along ridges. Seeds obovoid, brown, ca. 2 mm long, slightly compressed, pubescent with spirally sculptured hairs.

Phenology.

Flowering and fruiting from October to December.

Distribution and ecology.

This new species was found under evergreen broad-leaved forest at an elevation of 1500-1700 m on the limestone mountain ridge, and was currently known as only one population in Mengla County, Yunnan, China. This distribution area is very close to the border with Myanmar and Laos. We assume that this species should be also distributed in Myanmar and Laos due to their similar habitat.

Etymology.

The specific epithet “Chenmoui” was dedicated to the famous Chinese collector and botanist, Chen Mou (陈谋) (1903-1935) who was one of the founders of the first botanical garden cataloged by the Classification System of Plants in China, and died during the collection trip through southern Yunnan, China. The Chinese name was given as “陈谋凤仙花”.

Conservation status.

This species is currently known only from one population in the type locality. The population is located in the tourist area of Kongming Mountain, where it could be easily disturbed by human activities, such as road construction and illegal mining. The IUCN status proposed is Vulnerable(VU) based on IUCN (2022) guidelines.

Additional specimens examined

(Paratype). China, Yunnan province, Mengla county, Xiangming Yi nationality township, Kongming Mountain . 24 Oct. 2019, Ruhua Xu and Yu Zhang, XRH001 (CSH!) .

Note.

New species of sect. Impatiens Uniflorae discovered from Southeast Asia in recent years were mostly found distributed on mountain summits in an evergreen forest, which indicated that the stone mountain in this area was likely to be one of the speciation centers of this section. Impatiens Impatiens species exhibited interspecific and even intraspecific variation in spur length, at least from our observation of the same population of I. davidii Franchet, I. platysepala Y. L. Chen, and I. chenmoui , which may be considered as retaining of a bimodal pollinated system of bee and lepidopteran ( Ruchisansakun et al. 2016). Floristic survey and pollination ecology study in these regions’ Impatiens species is still insufficient, and more fieldwork is urgently needed.

Figures

Figure 2. Impatiens chenmoui sp. nov. A habit B, C flower with long spur D, E flower with spur nearly absent F leaf base G capsule H dorsal petal I spur J lateral sepals K united lateral petals L ovary surrounded by stamens.

Figure 3. Impatiens chenmoui sp. nov. A habit B, C united lateral petals D ovary surrounded by stamens E flower front view F, G lateral sepals H spur I dorsal petal J-L leaves M seed N capsule O, P long-spurred flower side view Q non-spurred flower side view.

Figure A 1. Holotype of Impatiens chenmoui sp. nov.