Impatiens leptocarpa Hook.f., Rec. Bot. Surv.

Tian, Jing, Yuan, Tao-Hua, Peng, Shuai, Yang, Zhu-Zhu, Hu, Guang-Wan & Wang, Qing- Feng, 2024, A new species of Impatiens (Balsaminaceae) from Southern Xizang, China with supplementary knowledge on I. leptocarpa Hook. f., Phytotaxa 661 (1), pp. 47-62 : 52-59

2. Impatiens leptocarpa Hook.f., Rec. Bot. Surv. India 4: 17. 1905; Grey-Wilson, Fl. Bhutan 2: 100. 1991; Vivek. et al., Fl. India 4: 172. 1997; Gogoi et al., Balsams of Eastern Himalaya—A Regional Revision: 114. 2018; Gogoi et al., Wild Balsams of Darjeeling and Sikkim Himalaya: 154. 2021; Gogoi et al., Flora of Sikkim- A Pictorial Guide: 113. 2021; Raskoti & Ale, PLOS ONE 17(10): 32. 2022. ( Fig. 5 )

Type: — INDIA. West Bengal: Darjeeling, Phalut , Oct. 1903, Prain’s collector 52 I (holotype: K, K000694798 , image!) .

Description: Annual, non-succulent herbs, 60–80 cm high; stems sparsely branched. Leaves confined mainly to the upper part of the stem, whorled; petiole 0.5–2.5 cm long; extra-floral nectaries absent; leaf blade elliptic to ovate, 5–9 × 2–4 cm, glabrous to mildly hairy, margins crenate. Inflorescence axillary, ascending, up to 25-flowered; peduncle 4–5 cm long; pedicel 1.0– 1.5 cm long, bracts ovate to lanceolate, 0.2–0.3 cm long, apex awned, persistent. Flowers yellow speckled red or without red spots; lateral sepals 4 (in 2 pairs), outer pair ovate to lanceolate, 0.2–0.3 × 0.1–0.2 cm, apex awned, inner pair lanceolate, 0.2–0.3 × 0.1 cm; lower sepal straight, tubular-funneliform, 1.5–2.0 cm deep, abruptly constricted into a short down-curved spur; dorsal petal broadly ovate to suborbicular, 0.5–0.6 × 0.4–0.7 cm; lateral united petals yellow speckled red, upper petal obovate to sub-orbicular, 0.5–0.6 × 0.6–0.8 cm, lower petal oblong-dolabriform, 0.8–1.0 × 0.3–0.4 cm; stamens yellow. Ovary 5-carpellate. Capsules linear, sub-torulose, 1.8–2.2 cm long. Seeds unknown.

Distribution: — Impatiens leptocarpa is found in East Nepal, North India, and Xizang, China. Etymology:— The word “ leptós” is derived from ancient Greek, signifying thin or slender, and “carpa” denotes fruit or fruitful. The Chinese name is given as “细果凤仙花” (xì-guǒ-fèng-xiān-huā).

Phylogenetic position:— Phylogenetic analysis indicates that Impatiens leptocarpa is nested within I. sect. Racemosae and shares a close relationship with I. radiata and I. harae . The clade consisting of the newly recorded species and its close relatives is strongly supported by phylogenetic evidence ( Fig. 4 ).

Additional specimens examined: — NEPAL. Sankhuwasabha , north of sando pokhari near barun khola, 3400 m, 22 Aug. 1981, Grey-Wilson & Henderson 4141 (E, E00752894, image!; K, image!) . CHINA. Xizang, Shannan, Lhunze, Zhari , evergreen broad-leaved forests along understory streams, 2682 m, 28°36′7″N, 93°24′15″E, 14 July 2022, J. Tian & C. Zhang TIBET-TJ7 (HIB, HIB0209750, HIB0209751, HIB0209752) .

Notes:— In the protologue of Impatiens leptocarpa, Hooker (1905) did not cite any collection, and only provided the type locality, viz. Sikkim. We searched online databases of many herbaria (A, BM, BSI, DD, E, HK, JSTOR, K, L, MACH, US, W). Finally, a total of four specimens of this species were found in K and E. There are three specimens of the name in K. One specimen (K000694798) was collected by David Prain from Sikkim, India in October 1903 and another two specimens were collected by Grey-Wilson and Henderson from Sankhuwasabha, Nepal on 22 August, 1981. A duplication of the later gathering is deposited in E (E00752894). Thus, the only one specimen collected from Sikkim should be holotype.

Sometimes, the type collection number of Impatiens leptocarpa was mistaken as “Prain's collector 521” ( Gogoi et al. 2018) or “Prain's collector 511” ( Raskoti & Ale 2022). However, according to the label on the type, “Prain's collector 52 I” is correct.

Figures

FIGURE 4. The phylogenetic tree based on a combined dataset of nrITS and plastid atpB-rbcL DNA sequences.The bootstrap percentages (BP) for maximum likelihood (ML) and posterior probabilities (PP) of Bayesian inference (BI) are shown in the branch (BP/PP, the dash [-] indicates BP<80 or PP<0.80 at a node, and the asterisk [*] indicates BP=100 or PP=1.00). Only the ML tree is shown, because its topology is nearly identical to the BI tree. Impatiens lhunzeensis and I. leptocarpa are highlighted in red.

FIGURE 5. Impatiens leptocarpa. A. habit; B. root and basal part of stem, showing node; C. glands on petiole base and stem; D. inflorescence; E. front and lateral view of flower (b. outer lateral sepals, b’. inner lateral sepals); F. dissection of a flower (a. dorsal petal; b. outer lateral sepals; c. lateral united petals; d. lower sepal; e. stamens); G. capsules. Photographed by Jing Tian.