Impatiens occultans Hook. f., Rec. Bot. Surv. Ind.
Creators: name: Guo, Hui
name: Wei, Lai
name: Hao, Jia-Chen
name: Du, Yu-Fen
name: Zhang, Lin-Jing
name: Yu, Sheng-Xiang
Publisher: name: Zenodo
Year: 2016
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Magnoliopsida
Ericales
Balsaminaceae
Impatiens
Impatiens occultans

description: Impatiens occultans Hook.f., Rec. Bot. Surv. Ind. 4: 17 (1905).
Type:— INDIA. Sikkim: Tankra Mts, 13500 ft, 2 Aug 1891, G. A. Gammie 414 (holotype K!).
Herbs perennial, 15–20 cm tall, glabrous. Stems simple, erect, fleshy; inferior nodes slightly swollen. Leaves alternate; blade elliptic, 2–3 × 1–1.2 cm, apex acuminate, base cuneate, deep green above, pale green beneath, margin deeply and sparingly crenate with conspicuous sinus bristles, lateral veins distinct; petioles ca. 0.5 cm. Flower solitary in upper axils; peduncle 2–3 cm long; bracts lanceolate, ca. 5 mm long, acute; pedicels thin, 3–5 mm long. Flowers pale purplish blue with purplish red patches in mouth. Lateral sepals 4; anterior small, 0.8–1.0 × 1.2–1.5 mm, glandiform; posterior large, ovate to lanceolate, 2- or 3- veined, yellowish green, base rounded, apex acuminate to caudate, 2.5–3.6 × 1.5–2.1 mm. Lower sepal 1.2–1.5 cm long without spur, navicular. Dorsal petal 4–6 × 3–5 mm, apex rounded, base broadly cuneate, midrib not distinct. Lateral united petals 8–12 mm long, lower lobes 8–10 × 3–5 mm, oblong, the upper 3–5 × 2–3 mm, elliptic, inner margin without appendage. Stamens 5; filaments linear, 2–3 mm long; anthers obtuse. Ovary narrowly fusiform. Capsule short, fusiform, middle part inflated.
Phenology: Flowering and fruiting from July to August.
Ecology: Impatiens occultans was found growing near rocks in the pass between Gyirong to Sale at an altitude of over 4000 m in an alpine meadow.
Distribution: Impatiens occultans was first discovered in northern Sikkim, India, by G. A. Gammie (Hooker 1905), and later found in central and eastern Nepal (Hara 1979). The species occurs in China (Xizang: Gyirong), Nepal (Beni Kharka, Chhurchathanga, Choarma, Chodo Gyabo, DudhKund, Koshing Kharka, Lamni Nama, Namikhil, Neju, Pike Dongshar, Sarkari Pati, Sete, Taktor, Thare Og, Thosa Kharka, Thudam, and Topke Gola), and India (Sikkim, Tankra) (Akiyama et al. 1991).
Palynology: In Impatiens occultans, the pollen size (P×E1×E2: length of polar axis × length of long equatorial axis × length of short equatorial axis) is (21.3–21.6) × (47.1–47.4) × (23.3–23.8) μm. The pollen is tetracolpate, oblong in polar view, the colpi are thin, and the exine possesses reticulate ornamentation and with dense granules in the lumina. The lumina are smaller close to the colpi (Fig 3 A–C). The pollen size (P×E1×E2) of I. tuberculata Hook. f. et Thoms. (1860: 155) is (12.1–12.6) × (26.9–27.5) × (17.1–17.8) μm. The pollen is tetracolpate, elliptic in polar view, the colpi are thin, and the exine possesses reticulate ornamentation with dense granules in the lumina (Fig 3 D–F). From the results of pollen grains observation, I. occultans is similar with the latter in shape, superficial ornamentations and second sculptures, but the former is larger than the latter in size.
Additional specimens examined:— CHINA. Xizang: Gyirong, 28˚23’ N, 85˚24’ E, 4004 m, 28 July 2015, Lai Wei & Jia-Chen Hao 15397 (PE); 28˚23’ N, 85˚21’ E, 2800–3970 m, 23 July 2013, PE-Xizang Botanical Expedition 3992 (PE). NEPAL. Rolwaling Khola, 3600–4050 m, 4 September 1983, H. Ohba et al. 8320622 (TI); Khare Khola, 4000 m, 12 September 1983, H. Ohba et al. 8331975 (TI); Chhurchathanga, 3200–3600 m, 10 August 1977, H. Ohashi et al. 770637, 772219 & 773661 (TI); Janakpur Zone, 22 July 1985, H. Ohba et al. 8570653 (TI); Sagarmatha Zone, 19 August 1985, H. Ohba et al. 8520278 & 8571790 (TI); 9 September 1985, H. Ohba et al. 8531381 (TI).
Discussion: The topologies of the ITS and atpB-rbcL + trnL-F trees are congruent with each other, and also agree with those from Yu et al. (2016). They yield a sister relationship between Impatiens occultans and I. tuberculata, and is included in a clade of sect. Racemosae, subg. Impatiens (Fig 4, S 1, S 2). Morphological data (Fig 4, S 1, S 2) confirm this relationship. Impatiens occultans is similar to I. tuberculata, but differs in its elliptic (vs oblanceolate) blade, 1-flowered (vs 4- to 10-flowered) raceme, 4 (vs 2) lateral sepals and glabrous (vs tuberculate) capsule. In Table 1, Impatiens occultans is compared with related and/or similar species (I. tuberculata, I. laxiflora Edgew. (1851: 39) and I. radiata Hook. f. (1875: 476)).
description: Published as part of Guo, Hui, Wei, Lai, Hao, Jia-Chen, Du, Yu-Fen, Zhang, Lin-Jing & Yu, Sheng-Xiang, 2016, Impatiens occultans (Balsaminaceae), a newly recorded species from Xizang, China, and its phylogenetic position, pp. 62-68 in Phytotaxa 275 (1) on pages 65-67, DOI: 10.11646/phytotaxa.275.1.7, http://zenodo.org/record/13647021