Impatiens longyangensis Y.Y.Cong, G.W.Hu & S.Peng, 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 : 272-275

1. Impatiens longyangensis Y.Y.Cong, G.W.Hu & S.Peng , sp. nov. ( Figure 1 : A–F)

Diagnosis: —The new species is morphologically similar to Impatiens shangjiangensis Y.Y.Cong & J.Z.Gu in Gu et al. (2021:197), but can be easily distinguished by having shorter petiole without clavate glands (vs. a pair of clavate glands), ovate-lanceolate or lanceolate (vs. oblong or ovate-oblong) lamina, 2.2–5 cm (vs. 6–13 cm) long peduncle with sparsely puberulent (vs. glabrous) base, ovate (vs. linear or narrowly lanceolate) bract, shortly saccate lower sepal with a longer spur (18.3–24.3 mm vs. 6–11 mm), suborbicular (vs. reniform) dorsal petal and ovate (vs. suborbicular) basal lobes with an acuminate (vs. obtuse) apex. A more detailed morphological comparison of the two species is provided in Table 2 .

Type: — CHINA. Yunnan, Baoshan City, Longyang District, Mangkuan Township , moist places under the forests, 25°17’42.98”N, 98°46’29.33”E, elev. 2391m, 25 October 2021, Shuai Peng PS-00435 (holotype: HNNU!, isotypes: HNNU!, HIB!) .

Annual herb, 40–100 cm tall. Stem erect, much branched. Leaves alternate, often aggregated on upper part of stem. Petioles 0.9–1.6 cm long at middle and lower stem, subsessile on upper stem. Lamina 7.3–14.8× 2.1–4.5 cm, ovatelanceolate or oblong-lanceolate, membranous, adaxially green and sparsely puberulent, abaxially gray-green and glabrous, apex long acuminate, base cuneate, margin crenate-serrate, setose between marginal teeth, lateral veins 8–12 pairs. Inflorescences racemose, terminal or axillary, 4–13-flowered; peduncle 2.2–5 cm long, slender, sparsely puberulent at base; pedicels 1.1–2.8 cm long, slender, with a bract at base; bract 2.8–3.5× 2–2.8 mm, ovate, persistent. Flowers pale purple, 3–3.2 cm long. Lateral sepals 2, 4–5× 2.3–3 mm, obliquely ovate, apex acuminate. Lower sepal shortly saccate, 9–11 mm deep excluding spur, 8.5–11.3 mm wide, tip of mouth with a small rostellum, base gradually narrowed into a spur, spur 18.3–24.3 mm long, the distal part of spur strongly recurved and S-shaped; dorsal petal suborbicular, base broadly cuneate, abaxial midvein slightly thickened, 8.3–10.5× 8–10.5 mm; lateral united petals shortly clawed, 2-lobed, basal lobes ovate, 6.5–9.3× 4–6 mm, apex acuminate, distal lobes narrowly dolabriform, 12–18.8× 6.5–8 mm, auricle inflexed. Stamens 5, 7.3–8.3 mm long, 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, ca 5 mm long. Capsule linear, 2–2.5 cm long, apex acuminate, 5-valved, fleshy. Seeds brown, oblong, ca. 3 mm long.

Distribution and ecology:— Impatiens longyangensis is only found in the central Gaoligong Mountains. It grows in moist places under the forests on the roadside at elevations of 2391–2420m. The main associated species included Acer Linnaeus (1753: 1054) sp. , Phoebe Nees (1836: 98) sp. , Vitis Linnaeus (1753: 202) sp. , Rubus Linnaeus (1753: 492) sp.

Etymology:—The specific epithet “ longyangensis ” refers to the type locality, Longyang District, Baoshan City, Yunnan Province. The Chinese name is “ ẕșū仙ĸ ”.

Phenology:—Flowering and fruiting of this new species is from early September to mid-November.

Micromorphological observations:—Seeds: oblong, 2.88 (2.67–3.09) × 1.59 (1.57–1.60) mm, L (long)/W (wide) = 1.81, surface of seed coat with conspicuously elevated cells and irregular granules, elevated epidermal cells unevenly with granular appendages and holes on the surface ( Figure 3 : A–C).

Conservation status:—Two populations composed of ca. 400 individuals have been found in the Gaoligong Mountains National Nature Reserve, where little interference from human activities occurs. But more detailed data from further population investigations are needed.Thus, we recommend that the taxon should be considered of Data Deficient (DD), according to the guidelines made by IUCN Standards and Petitions Subcommittee (2022).

Figures

FIGURE 1. Impatiens longyangensis. (A‒F) and I. shangjiangensis (G‒I). A habit; B infructescence; C adaxial and abaxial view of leaf; D, G front view of flower; E, H lateral view of flower; F, I dissection of a flower A‒E & G‒H: photographed by Yi-Yan Cong, F & I: 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.