Impatiens drepanophora Hook.f.

Smets, E. F. & Janssens, S. B., 2018, Balsaminaceae of Myanmar, Blumea 63 (3), pp. 199-267 : 228-229

21. Impatiens drepanophora Hook.f. — Map 9; Plate 2c

Impatiens drepanophora Hook.f. (1905) 17; Fedde (1905) 432; Diels (1912) 7; Toppin (1920) 364; H.Hara & L.H.J.Williams (1979) without page number; Y.L. Chen et al. (2007) 55. — Type: Hooker & Thomson 56 (lecto, designated here K K000694682; isolecto K K000694683, K K000694684, K K000694685,K K000694686,K K000694687,L L0388881), India,Khasia Hills, 6 July 1850, alt. 6000 ft.

Terrestrial, annual herb, 35–40 cm tall. Stem erect, simple to laxly branched, glabrous. Leaves spirally arranged. Petiole 0.5–3(–5) mm long, glabrous. Lamina 50–130 by 18–60 mm, ovate to ovate-lanceolate, apex acuminate, base cuneate to attenuate, margin serrate, glabrous, with 2 stipitate glands near leaf base; lateral veins (5–)7–9 pairs. Inflorescence axillary to subterminal, erect, (5–)7–15(–34)-flowered raceme. Peduncle 30–75 mm long, glabrous. Rachis 10–60 mm long. Flowers 30–45 mm long, asymmetric, white to yellow. Bracts 1.5–5 by 0.5–2 mm, ovate to lanceolate, apex acuminate and aristate with long awn, base cuneate, margin entire, glabrous, caducous. Pedicel 9–22 mm long, slender, glabrous. Lateral sepals 2, 2.5–4 by 1–2 mm, free, ovate-falcate, the long apex aristate, base obtuse, glabrous. Lower sepal 8–10 mm long, 18–20 mm deep, deeply navicular, apex acuminate and aristate with long awn, yellow with red dots, glabrous, constricted into an upcurved spur, sometimes involute, 5–15 mm long, minutely bifid. Dorsal petal 9–17 by 5 mm, ovate to orbicular, flat, strongly reflexed backward, apex obtuse to round, base cuneate to obtuse, abaxial midvein simple or with a narrow crest, glabrous. Lateral united petals free, asymmetric: the left upper petal 8–10 by 3–4 mm, curved spatulate, apex acute, base stipitate; the right upper petal c. 9 by 5 mm, obovate to elliptic, apex acuminate, base obtuse, margin entire; the lower petals free; the left lower petal 14–22 by 2–5 mm, oblong to dolabriform, apex obtuse, glabrous; the right lower petal c. 15 by 3 mm, lanceolate, apex acute. Stamens: filaments c. 4 mm long. Ovary glabrous. Fruits 9–13 mm long, 1–2 mm diam, narrowly clavate, glabrous.

Phenology — Flowering: July to November; fruiting: September to November.

Distribution — Myanmar (Kachin State), China (Tibet Region, Yunnan Province), India (Khasia Hills).

Ecology — Growing in open, grassy areas in evergreen forest, 1100–2200 m altitude.

Other collections examined. CHINA, Yunnan Province, Wu et al. 2451 (PE PE01878257*), Hydrologic Station , 23 Oct. 1995 ; Tibet Region, Unknown 1698 (PE PE00061865*), Medog County, 10 Aug. 1974 . – MYANMAR, Kachin State, Toppin 2778 (K H2015/00092 7, H2015/00092 8, H2015/00092 9, BM), NE Burmah, alt. 5000–7000 ft (1524–2134 m); Buchanan 5568 (E E00753037, E E00753038, K H2015/00092 10), Myitkyina, Sima Hills , east of Irrawaddy, 3500–4000 ft (1067–1219 m), 1 Nov. 1911 ; Kaulback 327 (BM), Myitkyina, N26°06' E97°58', alt. 4500 ft, 9 Aug. 1939; Ruchisansakun & Thet Yu Nwe 753 (L L2071175, MAND, RAF), Myitkyina, Sa Daung village , along the road side, N25°25'40.8" E97°56'32.3", alt. 1452 m, 18 Nov. 2015 ; Kaulback s.n. (BM), Nam Taqmai Valley , N27°42' E97°54', alt. 4000 ft (1219 m), 14 Aug. 1938 .

Notes — Impatiens drepanophora differs from I. stenantha by having a narrowly clavate fruit vs a linear fruit, a slightly upcurved spur vs a strongly re-upcurved spur, and a broadly ovate-falcate, long aristate spur vs a linear-falcate spur with an acute to obtuse apex.

Hooker did not clearly designate a type specimen of I. drepanophora . We select Hooker & Thomson 56 (K000694682) as lectotype because it was collected by Hooker and includes an illustration.

During our expedition, we observed that this species was visited and pollinated by bees.