Impatiens uncata Y.Y. Cong & J.J. Zhou

Qiu, Kan-Ying, Zhou, Jian-Jun, Xiang, Jian-Feng, Liu, Ang, Fei, Dong-Bo, Liu, Song, Yu, Xun-Lin & Cong, Yi-Yan, 2024, Impatiens uncata (Balsaminaceae), a new species from Hunan, China, Phytotaxa 659 (3), pp. 286-294 : 288-291

Impatiens uncata Y.Y. Cong & J.J. Zhou sp. nov. ( Figures 2 & 3 )

Type:— China, Hunan Province, Yongzhou City, Ningyuan County, Shunling Sub-district , Lianhua Mountain . 111°57′0.65″E, 25°34′26.29″N, elevation 213m, 20 July 2022, Jian-Jun Zhou and Jian-Feng Xiang NY22072001 ( holotype: HNNU!; isotypes: HNNU!, IBSC!, HIB!) .

Diagnosis:— Impatiens uncata is similar to Impatiens huangyanensis , but is distinct from the latter in having taller plants, leaves with ovate or ovate-lanceolate blades and longer petioles, purple flowers, longer bracts, broadly ovate-rounded lateral sepals, white broadly funnelform lower sepal, 2-lobed spur with a swollen apex, purplish dorsal petal, white basal lobes and bigger distal lobes with a retuse apex ( Figures 3 & 4 ).

Description:— Annual herb, 50–85 cm tall. Stem erect, well branched. Leaves alternate, towards the stem apex aggregated. Petioles 3.2–6.5 cm long, lamina 6.5–11.7 × 2.8–4.3 cm, ovate, or ovate-lanceolate, glabrous, apex acuminate, base cuneate, margin crenate, lateral veins 4–7 pairs. Inflorescences in upper leaf axils, 1–2 flowered; peduncle 0.7–1.5 cm, glabrous, pedicels 1–1.7 cm, slender, with bract at base; bracts persistent, linear-lanceolate, ca. 2mm long, apex acuminate. Flowers purple, 2–3 cm long. Lateral sepals 2, broadly ovate-rounded, 8–11 × 7–9 mm, abaxial midvein thickened, apex mucronulate. Lower sepal broadly funnelform, with a yellow patch at base, 1.9–2.1 cm deep excluding spur, base abruptly narrowed into a hooked, 2-lobed spur, spur 0.4–0.7 cm long, apex swollen to tuberiform, mouth flat, 2–2.3 cm wide; dorsal petal 1.1–1.4 × 1.6–1.7 cm, reniform-orbicular, apex emarginate, mucronulate, abaxial midvein thickened, cristate at middle; lateral united petals shortly clawed, 2-lobed, basal lobes narrowly lorate, 1.2–1.4 × 0.2–0.3 cm, apex acuminate; distal lobes dolabriform long clowed, purple striate, 2.6–2.8 × 1.1–1.4 cm, apex retuse, auricle inflexed, yellow, rounded. Stamens 6–7 mm, filaments linear; anthers ovoid, joined into a ring surrounding ovary apex, apex acute; ovary superior, 5-carpellate, erect with axile placentation, fusiform, ca. 5 mm long. Capsule linear, apex long rostellate, ca. 2.5 cm, 5-valved, fleshy. Seeds ellipsoid.

Phenology:—The new species was observed flowering from July to August, fruiting from August to September.

Etymology:—The specific epithet " uncata " refers to the hooked spur that locates at the base of the lower sepal of the new species. The Chinese name is “̎距凤仙花”.

Distribution and ecology:— Impatiens uncata grows under the limestone evergreen broad-leaved forests, shaded moist places. The main associated species includes Quercus glauca Thunberg (1784: 175) , Speranskia cantonensis ( Hance 1878: 16) Pax & K. Hoffm (1912: 15) , Mallotus philippensis ( Lamarck 1786: 206) Müller Argoviensis (1865: 196) , Gymnocladus chinensis Baill (1875: 34) , Tarenna depauperata Hutch (1916: 411) . Presently, the new species is known only from Ningyuan County, Hunan, China.

Phylogenetic position:—Bayesian phylogenetic analysis and maximum likelihood analysis of the combined ITS and atpB-rbcL datasets unequivocally establish its taxonomic position within Impatiens sect. Impatiens , revealing a close phylogenetic affinity to I. huangyanensis ( Figure 1 ).

Conservation status:—Field investigation have revealed that the number of mature individuals of Impatiens uncata is less than 250. In accordance with the IUCN (2019) guidelines, the proposed conservation status is 'EN' (Endangered), primarily based on Criterion D, which denotes a very small or restricted population size.

Figures

FIGURE 1. Phylogenetic tree based on a combined dataset of nuclear ribosomal ITS and plastid atpB-rbcL DNA sequences. Posterior probabilities (PP) from Bayesian analysis are shown above the branch, and bootstrap value (BS) for maximum likelihood (ML) analyses are shown below the branch. Impatiens uncata is highlighted in red.

FIGURE 2. Impatiens uncata Y.Y. Cong & J.J. Zhou, sp. nov. A. Upper part of plant. B. Lower part of plant. C. Flower in lateral view. D. Flower in front view. E. Dorsal petal. F. Lateral sepals. G. Lateral united petal. H. Lower sepal. I. Androecium. J. Capsules. K. Seeds. L. Dehiscent fruit. Drawing by Jing Tian.

FIGURE 3. Impatiens uncata Y.Y. Cong & J.J. Zhou, sp. nov. A. Habit. B. Inflorescence.C. Leaves. D. Roots. E. Capsules. F. Front view of flower. G. Lateral view of flower. H. Dissection of a flower. Photographs by Jian-Jun Zhou.

FIGURE 4. Impatiens huangyanensis X.F. Jin & B.Y. Ding. A. Habit. B. Flowering plants. C. Front view of flower. D. Lateral view of flower. E. Capsules. F. Dissection of a flower. G. Inflorescences. Photographs by Yi-Yan Cong.