Impatiens holocentra Hand.-Mazz.

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

22. Impatiens holocentra Hand.-Mazz. — Map 10; Plate 2d

Impatiens holocentra Hand.-Mazz. (1933) 647; Y.L. Chen et al. (2007) 54. — Type: Handel­Mazzetti 9405 (holo WU0059598*), China, Yunnan Province, in a valley near boarder of Tibet-Myanmar , N27°53', alt. 1725–2150 m, 6 July 1916.

Terrestrial, perennial herb, 50 cm tall, with tuberous root. Stem erect, 2–5 mm diam, moderately branched, terete, green to purplish green, glabrous. Leaves spirally arranged. Petiole 4–6 mm long, 1.5–2 mm diam, angular, glabrous. Lamina 70–125 by 35–40 mm, ovate, apex acuminate, base cuneate, margin serrate, papyraceous, adaxial dark green, abaxial glaucous, glabrous, with one pair of red, clavate glands at petiole base; lateral veins 6–9 pairs. Inflorescence axillary, erect, 2–4-flowered raceme. Peduncle 13–20 mm long, <1 mm diam, green, glabrous. Rachis 2–17 mm long, <1 mm diam. Flowers 25–30 mm long, 17 mm deep, asymmetric, yellow. Bracts c. 2 by <1 mm, linear, apex acute, base cuneate, margin entire, without glands, red to brown, glabrous, persistent to caducous. Pedicel 10–15 mm long, <1 mm diam, green, glabrous. Lateral sepals 2, c. 2 by 1.5 mm, free, ovate, apex acute and mucronate, base obtuse, green to yellow. Lower sepal c. 10 by 5 mm, 15 mm deep including spur, infundibular, apex short aristate, c. 1 mm, yellow, glabrous, dorsal part gradually narrow into a straight spur, yellow. Dorsal petal c. 10 by 8 mm, c. 4 mm deep, ovate, cucullate, apex round to obtuse, base truncate to cordate, yellow, glabrous, abaxial midvein with a narrowly crescent-shaped crest, c. 3 mm wide crest. Lateral united petals 23–25 mm long, free: the upper petals c. 9 by 3–4 mm, elliptic, apex acute, base cuneate, yellow with red steaks, the right one reflected at the base; the lower petals 17–20 by 2–2.5 mm, free, linear, apex acute to obtuse, base without auricle, yellow, glabrous. Stamens: filament unknown. Ovary 5-carpellate, green, glabrous. Fruits c. 27 mm long, c. 3 mm diam, linear, 5-lobed, glabrous. Seeds unknown.

Phenology — Flowering: July to November.

Distribution — Myanmar (Kachin State), China (Yunnan).

Ecology — Growing in moist and shady areas in evergreen forest, 1700–2200 m altitude.

Other collections examined. MYANMAR, Kachin State, Ruchisansakun & Thet Yu Nwe 755 (L L2071185, MAND, RAF), Myitkyina, Kan Paik Ti, N25°24'08.6" E98°06'56.4",alt. 1998 m, 18 Nov.2015 ; Kingdon­Ward 21084 (BM), Tama Bum, alt. 9500 ft, 26 June 1953.

Note — Impatiens holocentra can be easily distinguished from the other species in the sect. Racemosae in Myanmar by its deeply bucciniform lower sepal. Handel-Mazzetti (1933) clearly designated that the type is Handel­Mazzetti 9405 deposited in WU.