Impatiens chinensis

Smets, E. F. & Janssens, S. B., 2018, Balsaminaceae of Myanmar, Blumea 63 (3), pp. 199-267 : 235

33. Impatiens chinensis L. — Map 13; Plate 2h

Impatiens chinensis L. (1753) 937; Collett & Hemsl. (1890) 30; Hook.f. & Thomson (1860) 119; Tardieu (1945) 559; W.J. Kress et al. (2003) 169; Y.L. Chen et al. (2007) 57; J.R.N.Dessai & Janarth. (2011) 26, 40. — Balsamina chinensis (L.) DC. (1824) 686. — Type: Anonymous s.n. (lecto, designated in Singh (2017) LINN-HL1053-1*).

[Onapu, Van Rheede tot Drakestein 1689:89,t. 47]. — Impatiens fasciculata Lam. (1785) 363; Wight & Arn. (1834) 138; Hook. (1852) t. 4631; Wight (1846) t. 748. — Balsamina fasciculata (Lam.) DC. (1824) 686; G. Don (1831) 749, syn. in Hooker & Thomson (1860). — Type: Van Rheede tot Drakestein Tab.47 (1689) (lecto, designated here illustration).

Balsamina setacea Colebr. ex Hook. (1824) t. 137. — Impatiens setacea Colebr. MSS. ined. ( Hooker 1824), syn. in Hooker & Thomson (1860). — Type: India, Kerrera Mountain .

Impatiens chinensis L. var. brevicornis E. Barnes (1939) 99,syn.in J.R.N.Dessai & Janarthanum (2011). — Type: Barnes 558 (lecto, designated in Dessai & Janarthanum (2011) K K000580488), India, Kerala, Idukki district , Travancore, Munnar, 20 Oct. 1932 ,.

Impatiens chinensis L. var. gracilissima , nom. nud., in herb. — Buchanan 2 (K K000694706), Myanmar, Kachin State, Myitkyina, east bank of the Irrawaddy opposite Myitkyina , alt. 153 m, 30 Nov. 1910 .

Impatiens cosmia Hook.f. (1910b) t. 2915. — Type: Faber s.n. (lecto, designated in Dessai & Janarthanum (2011) W0016508*; Jacobs 186 (syn K K000381731), China, Cheking, Jungkun (Tungkun).

Impatiens heterophylla Wall. (1824) 458. — Balsamina heterophylla G. Don (1831) 749,syn.in Hooker & Thomson (1860). — Type: De Silva & H. Bruce s.n., Wall . Cat . no. 4748A (lecto, designated here K K001039813 (left specimen)), Sylhet, 1821.

Terrestrial to semi-aquatic, annual herb, 40–75 cm tall. Stem erect, the lower portion sometimes decumbent and often rooting at nodes, 4–9 mm diam, unbranched or rarely branched at the lower portion, reddish green to red, glabrous. Leaves decussate. Petiole sessile– 3 mm long, c. 1 mm diam, green, glabrous. Lamina 35–90 by 5–10 mm, oblong to linear, apex acute, base obtuse to truncate, margin shallowly crenate, adaxial dark green and hirsute, abaxial greyish green and glabrous, with one pair of stipular glands at petiole base; lateral veins 5 or 6 pairs. Inflorescence axillary, in 2- or 3-flowered fascicles. Flowers 35–45 by 30–40 mm, 3.5–3.8 mm deep, pink. Pedicel 45–50 mm long, 1–1.5 mm diam, cylindrical, red, glabrous. Bracts 2–2.5 by 0.5–1 mm, lanceolate, apex acute, base cuneate, margin entire, green, glabrous, persistent. Lateral sepals 2, 13–15 by 2–3 mm, free, linear to falcate, apex acute, base cuneate, dark pink with green tip, glabrous. Lower sepal 15–16 by 8–9 mm, c. 15 mm deep, navicular, apex acute and mucronate, base obtuse, pale pink, with dark pink reticulate lines, a white patch and yellow mark at the centre, apex green, glabrous, distal part abruptly constricted into an incurved to linear spur, sometimes laterally compressed, 20–22 mm long, pink. Dorsal petal 11–12 by 12–14 mm, broadly ovate, cucullate, apex acute and mucronate, base obtuse to truncate, pink, glabrous, abaxial midvein with a narrow crest terminating in a short acute point, crest green or pink. Lateral united petals 32–37 mm long, free: the upper petals 7–11 by 4–5 mm, falcate, apex acute to acuminate, base stipitate, pink; the lower petals 24–28 by 17–21 mm, free, broadly ovate, apex round to slightly bilobed, base auriculated, pink with dark pink auricles, glabrous. Stamens: filaments c. 8 mm long, pink or green; anthers yellow. Ovary c. 7 mm long, c. 2 mm diam, 5-carpellate, green, glabrous. Fruits 13–14 mm long, c. 3 mm diam, fusiform, 5-lobed, green, glabrous.

Phenology — Flowering: June to December.

Distribution — Myanmar (Chin State, Kachin State, Mandalay Region, Shan State, Tanintharyi Division), India, China, Laos, Thailand, Vietnam.

Ecology — Growing in swampy areas, 150–1300 m altitude.

Other collections examined. MYANMAR, Chin State, Venning 101 (K), Chin Hills, Kachin State, Ruchisansakun & Thet Yu Nwe 750 (L L2071165), Indawgyi lake Wildlife Sanctuary, base of Singaung Taung (Elephant mountain), N25°01'13" E96°19'28", alt. 184 m; Mandalay division, Lace s.n. (E E00753068), Maymyo Plateau, alt. 3500 ft, 1911; Lace 3260 (K), ibid., 19 June 1908; Ruchisansakun 704 (L L2071063,MAND, RAF), near to the lake, N22°00'30.82" E96°28'08.78", alt. 1080 m, 8 Aug. 2015; Dewan Mohinder Nath Nair 3726 (RANG4749), Enesakhan, near Maymyo, 22 Dec. 1958; Ruchisansakun & Thet Yu Nwe 761 (L L2071198, MAND, RAF), Mogok, Mintatar quarter, N22°55'03.7" E96°28'39.6", alt. 1133 m, 23 Nov. 2015; Shan State, Ruchisansakun 725 (L L2071103, MAND, RAF), Taunggyi, 20 Sept.2015; Melville 92 (BM), ibid.; Tanintharyi Region, Ruchisansakun et al. 739 (L L2071142),RAF nursery, 15 Oct.2015; Toppin 2780 (K H2015/00092 66, 67, 68), NE Burma, alt. 3000 ft, 18 Oct. 1914; Wall . Cat . no. 4748B (K K001039817), Taong (Toong) Dong, 1826.

Note — Impatiens chinensis has a large variation in leaf and spur shape between populations. It is most similar to I. oppositifolia but differs in having an incurved spur vs a short hook-like spur. Many published taxa have been synonymized under I. chinensis (see Dessai & Janarthanam (2011) for a detailed report).