Impatiens lacei Hook.f.

Smets, E. F. & Janssens, S. B., 2018, Balsaminaceae of Myanmar, Blumea 63 (3), pp. 199-267 : 254

61. Impatiens lacei Hook.f. — Map 20

Impatiens lacei Hook.f.(1910b) t. 2912; W.J. Kress et al.(2003) 170. — Type: Lace 2881 (lecto, designated here K K000694822; isolecto K H2015/ 00092150), Myanmar, Pegu District, banks of Pyinma Chaong , N17°20' E96°10', 7 Jan. 1906.

Terrestrial herb, 16–28 cm tall. Stem erect, simple to rarely branched, mostly glabrous to remotely pilose, densely pilose towards apex. Leaves spirally arranged. Petiole 15–30 mm long, pilose. Lamina 65–110 by 22–45 mm, lanceolate to ovate, apex acute to acuminate, base obtuse to attenuate, margin serrate to shallowly serrate, pilose on both sides, with many long hairs around lamina base and on petiole, up to 10 mm long, and one pair of clavate glands on petiole; lateral veins 6–9 pairs. Inflorescence axillary, pendulous, 1–3-flowered raceme. Peduncle 5–11 mm long, glabrous. Rachis absent – 2 mm long. Flowers 23–30 mm long, 35–43 mm deep. Bracts c. 1 by <1 mm, ovate to broadly ovate, apex acute and mucronate, base obtuse, margin entire, glabrous, persistent. Pedicel 7–16 mm long, glabrous. Lateral sepals 2, 4–5 by 2–2.5 mm, free, elliptic to ovate to obliquely ovate, apex acuminate to acute and mucronate, base obtuse to cuneate, glabrous. Lower sepal 15–18 mm long, 20–25 mm deep, deeply bucciniform, apex acute, glabrous, distal part abruptly constricted into an incurved spur, 8–13 mm long, bifid. Dorsal petal 10–11 by 12–15 mm, broadly elliptic to orbicular, cucullate, apex emarginate to round and mucronate, base round, glabrous, abaxial midvein with a crescent-shaped crest, 1–1.5 mm wide. Lateral united petals 20–23 mm long, free: the upper petals c. 13 by 9 mm, broadly ovate, obtuse, base cuneate; the lower petals c. 16 by 8 mm, free, obovate, obtuse, base with distinct auricles, glabrous. Stamens: filaments 4.5 m long. Ovary c. 4 mm long, c. 1 mm diam. Fruits c. 12 mm long, 3.5 mm diam, fusiform, glabrous. Seeds unknown.

Phenology — Flowering: July to January.

Distribution — Endemic to Myanmar (Bago Region,Ayeyarwaddy Region).

Ecology — Unknown.

Other collections examined. MYANMAR, Ayeyarwaddy Region, Allan 4842 (E E00752958, E E00752959, K), Henzada district , 1 Dec. 1908, Bago Division .

Note — Impatiens lacei can be easily distinguished from other species by the presence of many long hairs on the leaf margin, measuring up to 10 mm long. We found 2 sheets of Lace 2881 and we select K000694822 as a lectotype because this specimen is more complete and included dissected flowers.