Impatiens capillipes Hook.f. & Thomson

Smets, E. F. & Janssens, S. B., 2018, Balsaminaceae of Myanmar, Blumea 63 (3), pp. 199-267 : 214-216

5. Impatiens capillipes Hook.f. & Thomson — Fig. 10; Map 4; Plate 1d

Impatiens capillipes Hook.f. & Thomson (1860) 135; Hook. f. (1875) 456; (1905) 26; W.J. Kress et al. (2003) 169. — Type: Lobb 388 (lecto, designated here K K000694718; isolecto K K000694717), Myanmar (Burma), Moulmein, 1892.

Lithophytic, annual, glabrous herb, 25–40 cm tall. Stem erect, 2–4 mm diam, richly branched, angular, purple. Leaves spirally arranged. Petiole 8–15 mm long, 1–1.5 mm diam, angular,

Map 4 Distribution of Impatiens laevigata Wall. ex Hook.f. & Thomson var. laevigata (●), I. kerriae Craib (●), I. parishii Hook.f. (●) and I. capillipes Hook.f. & Thomson (●).

purple. Lamina 45–90 by 9–18 mm, narrowly ovate to narrowly lanceolate, apex acute to acuminate, base obtuse to attenuate, margin serrate, adaxial dark green, abaxial glaucous, with a purple clavate gland on each side of margin at or near the base; lateral veins 12–14 pairs. Inflorescence axillary, 2–4-flowered racemes. Peduncle, absent – 2 mm long, <1 mm diam, green. Flowers 8–10 by 8–9 mm, 4–5 mm deep, non-resupinate, white with pink and yellow marks. Pedicel c. 8 mm long, <1 mm diam, green to purple. Rachis c. 10 mm long, <1 mm diam, green to purple. Bracts <1 by 1 mm, lanceolate, apex acute, base cuneate, green. Lateral sepals 2, c. 1.5 by 1 mm, free, ovate to elliptic, apex acute, base obtuse, pale green. Lower sepal c. 3–4 by 2.5 mm, c. 2 mm deep, shallowly navicular, white with yellow mark and red dots at basal part, distal part abruptly constricted into an upward incurved spur, 1.5 mm long, white with green tip, blunt. Dorsal petal c. 5 by 2 mm, oblong, flat, apex acuminate, base cuneate, white, abaxial midvein simple. Lateral united petals connate: the upper pair c. 5 by 2–2.5 mm, ovate, apex acuminate, base obtuse, white; the lower pair 2.5–3 by 1–1.5 mm, connate, ovate, apex acuminate, white with purple spots at the base. Stamens: filaments c. 2 mm long, pink; anthers purple. Ovary c. 1.5 mm long, <1 mm diam, 4-carpellate, white. Fruits c. 8 mm long, 2.5–3 mm diam, clavate, 4-lobed, purplish green. Seeds 4.

Phenology — Flowering: November to December; fruiting: November to December.

Distribution — Endemic to southern Myanmar (Kayin State, Mon State).

Ecology — Growing on limestone in mixed deciduous forest,

10–100 m altitude.

Other collections examined. MYANMAR, Kayin State, Ruchisansakun & Thet Yu Nwe 744 (L, RAF, YNG), Hpa-An, Hae Pyan Cave, N16°50'08.0" 97°34'13.0", alt. 10 m, 18 Oct. 2015; Ruchisansakun & Thet Yu Nwe 749 (L, RAF, YNG), Hpa-An, N16°44'59.8" E97°47'04.8", 20 Oct. 2015; Mon State, Lobb 368 (K K000694716), Moulmein, 1846; Parish 454 (K), 1862; Parish s.n. (P04614864), 1862.

Notes — Impatiens capillipes is a distinct taxon characterized by very small, non-resupinate white flowers. It cannot be confused with any other Impatiens species from Myanmar.

Hooker annotated two sheets of Lobb 388 (K000694717, K000694718) as I. capillipes . We select K000694718 as lectotype because it includes a dissected flower and drawing.