Impatiens yaojiapingensis Y.Y.Cong, G.W.Hu & T.Hu, 2022

Hu, Tian, Peng, Shuai, Zhou, Xin-Xin, Zheng, Yi-Ming, Cong, Yi-Yan & Hu, Guang-Wan, 2022, Two new species of Impatiens (Balsaminaceae) from Gaoligong Mountains, Yunnan, China, Phytotaxa 566 (3), pp. 268-278 : 275

2. Impatiens yaojiapingensis Y.Y.Cong, G.W.Hu & T.Hu , sp. nov. ( Figure 2 : A–I)

Diagnosis: —The new species is morphologically similar to I. sterilis , but can be easily distinguished by oblong or oblong-ovate (vs. oblong to ovate) lamina that is sparsely pubescent (vs. glabrous) on both surfaces, petiole with 1–3 pairs of clavate glands (vs. with 1 pair of sessile globose glands), ± puberulent (vs. glabrous) peduncle, persistent (vs. caducous) bract, and lower sepal narrowing into a straight (vs. incurved) spur. A more detailed morphological comparison of the two species is provided in Table 3 .

Type: — CHINA. Yunnan, Lushui City, Luzhang Town, Yaojiaping , moist places on the roadside, 25°58’48.96”N, 98°42’34.87”E, elev. 2464m, 14 July 2021, Shuai Peng PS-00447 (holotype: HNNU!, isotype: HIB!) .

Annual herb, 60–100 cm tall. Stem erect, robust, base 1.2 cm in diam, much branched. Leaves alternate, often aggregated or subverticillate on upper part of stem. Petioles 2–5 cm long at middle and lower stem, shortly petiolate or subsessile on upper stem, with 1–3 pairs of clavate glands. Lamina 7–15× 2.5–5.8 cm, membranaceous, oblong or oblong-ovate, sparsely pubescent on both surfaces, apex long acuminate, base cuneate, margin crenate-serrate, setose between marginal teeth, lateral veins 7–10 pairs. Inflorescences racemose or corymbose, 4–11-flowered, terminal or axillary (at the later stage of the florescence, some reduced sterile inflorescences with slender and filiform peduncle produced on inner side of the fertile inflorescences); peduncle 1.2–3.8 cm long, slender, ± puberulent; pedicels 1.1–2.2 cm long, slender, with a bract at base; bract 4–5× 2–3 mm, ovate, persistent. Flowers yellow or pale purple, 2.5–3.5 cm long; lateral sepals 4, the outer 2 obliquely ovate, 7.3–8.8 × 4–5 mm, apex mucronate, the inner 2 extremely small, linear, ca. 1.5 mm long. Lower sepal saccate, 1–1.3 cm deep excluding spur, 1–1.6 cm wide, tip of mouth with a small rostellum, base abruptly narrowed into a straight spur, spur 1.2–1.7 cm long; dorsal petal suborbicular, base suborbicular, abaxial midvein slightly thickened, 7.5–11× 6.5–8.5 mm; lateral united petals shortly clawed, 2-lobed, basal lobes ovate, 10.8–14× 5.3–8 mm, apex acuminate, distal lobes lanceolate, 9–14× 4–6.8 mm, auricle inflexed. Stamens 5, 6–6.8 mm, filaments linear, free for ca. 1/2 their length; anthers ovoid, joined into a ring surrounding ovary apex, apex obtuse; ovary superior, 5-carpellate, erect with axile placentation, fusiform, 4–5.3 mm long. Capsule linear, 2.5–4 cm long, apex acuminate, 5-valved, fleshy. Seeds brown, oblong, ca. 3 mm.

Distribution and ecology: — Impatiens yaojiapingensis was only found in the central Gaoligong Mountains. It grows in moist places on the roadside at elevations of 2464–3012 m. The main associated species included Rubus Linnaeus (1753: 492) sp. , Rhododendron Linnaeus (1753: 392) sp. , Pteris Linnaeus (1753: 1073) sp. , Elatostema Forst & Forst (1776: 105) sp.

Etymology: —The specific epithet “ yaojiapingensis ” refers to the type locality, Yaojiaping, Lushui City, Yunnan Province. The Chinese name is “ 姚ṽ坪ū仙ĸ ”.

Phenology: —Flowering and fruiting of this new species is from early July to late October.

Micromorphological observations:—Seeds: oblong, 3.72 (3.61–3.83) × 1.98 (1.96–1.99) mm, L (long)/W (wide) = 1.88, surface with highly elevated epidermal cells and irregular granules, elevated cells appear finger like with granular appendages and holes on the surface and part of epidermal cells with short filiform derivants ( Figure 3 : D–F). Pollen grains: oblong in polar view, 29.85 (27.44–31.27) × 13.71 (12.30–14.84) μm, 4-colpate, exine with reticulate ornamentation, densely granulate in lumen ( Figure 3 : G–I).

Conservation status:—More than four populations have been found from elev. 2464 m to 3012 m, with a large number of individuals, so we recommend that the taxon be considered of Least Concern (LC), according to the guidelines made by IUCN Standards and Petitions Subcommittee (2022).

Figures

FIGURE 2. Impatiens yaojiapingensis. (A‒I) and I. sterilis (J‒M). A population; B habit; C inflorescence; D infructescence; E apex of stem; F, J glands on leaf base; G, K front view of flower; H, L lateral view of flower; I, M dissection of a flower.A‒H & J‒L: photographed by Yi-Yan Cong, I & M: photographed by Tian Hu.

FIGURE 3. Micromorphology of seed of Impatiens longyangensis (A‒C) and I. yaojiapingensis (D‒F), and micromorphology of pollen grain of I. yaojiapingensis (G‒I). A, D whole view; B‒C & E‒F: exine sculpture; G polar view; H equatorial view; I exine sculpture. Photographed by Tian Hu.