Impatiens bullatisepala G.W. Hu, Y.Y. Cong & Q.F. Wang, 2021

Peng, Shuai, Cong, Yi-Yan, Tian, Jing, Zhang, Cai-Fei, Hu, Guang-Wan & Wang, Qing- Feng, 2021, Impatiens bullatisepala (Balsaminaceae), a new species from Guizhou, China, Phytotaxa 500 (3), pp. 217-224 : 220-221

Impatiens bullatisepala G.W. Hu, Y.Y. Cong & Q.F. Wang sp. nov. ( Figures 1 , 2 : A–D)

Diagnosis: —The new species is morphologically similar to Impatiens davidii , but can be distinguished with the latter by its lateral sepals suborbicular, 1–1.5 cm in diameter, midrib ridged dorsally, lateral veins reticulate and sunk on the abaxial surface with bullate projections among veins; dorsal petal broadly ovate, 1–1.5 × 1.5–2 cm, dorsally with a green narrow arcuate cristate crest.

Type:— CHINA. Guizhou province, Jiangkou County, Fanjing Mountain , under evergreen broad-leaved forest, 27°53′44.21″N, 108°43′16.4″E, elevation 1027 m, 15 September 2018, Shuai Peng PS-0052 (holotype: HIB!; Isotype: HIB!, HNNU!)

Herbs annual, to 100 cm tall. Stem erect or procumbent in lower part, succulent, branched, glabrous, lower nodes swollen with many fibrous roots. Leaves alternate, petiolate; petiole 0.5–2 cm long; lamina elliptic to elliptic-lanceolate, 6–10 × 3–4.5 cm, margin coarsely crenate, teeth mucronulate, base obtuse to cuneate, with 3–4 pairs of glands, apex caudate-acuminate; glabrous; lateral veins 5–7 pairs. Inflorescences in upper leaf axils, 1-flowered; peduncle 1.8–2.8 cm long. Pedicel with 2 bracts above middle; bracts alternate, glabrous, upper one ovate, ca. 6 × ca. 4 mm, lower one subulate, ca. 2–3 mm long. Flower yellow, 4–5.5 cm long. Lateral sepals 2, sub-orbicular, 1–1.5 cm in diameter, apex mucronulate, margin entire, yellowish-green, glabrous, midrib ridged dorsally, lateral veins reticulate and sunk on abaxial surface with bullate projections among veins,; lower sepal deeply saccate, 2–2.5 cm deep, yellow with 6–7 orange red striations, glabrous; apex gradually narrowed into an abruptly incurved spur, spur 2-lobed, 1–1.3 cm long; mouth 1.5–1.9 cm wide, oblique with ca. 0.8 cm long narrowly triangular tip. Dorsal petal broadly ovate, 1–1.5 × 1.5–2 cm, apex emarginate and mucronulate, dorsally with a green narrow arcuate cristate crest at midvein; lateral united petals 2-lobed, 2.4–3.2 cm long, basal lobe ovate to elliptic, 5–7 × 3–5 mm, small, upper part with purple-red patches, apex abruptly narrowed into a purple-red filiform appendage, appendage up to 1 cm long; distal lobe dolabriform, 1.8–2.3 × 0.9–1.4 cm, yellow with red spots at base, inner margin curled with small auricle, apex with a short yellow filiform appendage. Stamens up to 4 mm long, filaments linear, slightly swollen above; anthers ovoid-orbicular, apex obtuse. Ovary erect, fusiform. Capsule linear, 2.8–3.5 cm long. Seed unknown.

Distribution and ecology: — Impatiens bullatisepala is currently known only from the type locality in Fanjing Mountain, Guizhou Province, China. It grows under the moist evergreen broad-leaved forests along the side of a creek.

Etymology: —The specific epithet “ bullatisepala ” refers to the lateral sepals with bullate projections netted in sunk reticulate veins on abaxial surface. The Chinese name is “泡ḛâ仙"”.

Phenology: —The new species was observed flowering from September to October, fruiting from October to November.

Phylogenetic position: —Bayesian phylogenetic analyses of the combined ITS and atpB-rbcL datasets proved its position within the Impatiens sect. Impatiens and closely related to I. davidii in the phylogenetic tree ( Figure 3 ).

V oucher specimens of Impatiens davidii : — China. Hunan: Yongshun County, Xiaoxi National Natural Reserve , 28°48′N, 110°11′E, elevation 650 m, 15 August 2018, S. Peng PS-0051 ( HIB) ; Jiangxi: Jiujiang City, Lushan Mountain, Guling Township , 29°34′N, 115°58′E, elevation 1050 m, 11 October 2018, G.W. Hu & S. Peng HGW-001138, G.W. Hu & S. Peng HGW-001140, G.W. Hu & S. Peng HGW-001142 ( HIB) .

Figures

FIGURE 1. Impatiens bullatisepala A. Plant in nature habit; B. Flower bud; C. Flower lateral view; D. Flower front view; E. Different parts of a flower; F. Fruit. Scale bars: B–F = 1 cm. Photographed by Shuai Peng.

FIGURE 2. Impatiens bullatisepala A–D: A. Flower bud; B. Flower lateral view; C. Flower front view; D. Different parts of a flower. Impatiens davidii E–K: E & I. Flower bud; F & J. Flower lateral view; G. Flower front view; H & K. Different parts of a flower. Scale bars:A–K = 1 cm.A–D & I–K: photographed by Shuai Peng, E–H: photographed by Guang-Wan Hu (A–D from S. Peng PS-0052 in HIB, E–H from G.-W. Hu & S. Peng HGW-001138 in HIB, I–K from S. Peng PS-0051 in HIB).

FIGURE 3. Bayesian phylogenetic tree base on a combined dataset of nuclear ITS and plastid atpB-rbcL DNA sequences, in which Impatiens bullatisepala is showing in red, and Bayesian posterior probabilities are indicated for each branch. (I. davidi1 from HGW- 001138, I. davidii2 from HGW-001140, I. davidii3 from HGW-001142, I. davidii4–6 from PS-0051, all specimens deposited in HIB)