Impatiens delicata Toppin

Smets, E. F. & Janssens, S. B., 2018, Balsaminaceae of Myanmar, Blumea 63 (3), pp. 199-267 : 255

63. Impatiens delicata Toppin — Map 21

Impatiens delicata Toppin (1920) 350; W.J. Kress et al. (2003) 169. — Type: Toppin4287 (lecto,designated here K K000694679;isolecto K K000694680), Myanmar, Sumprang, Kachin Hills, Dec. 1911.

Terrestrial herb, 8–12 cm tall. Stem decumbent, c. 2 mm diam, branched at the decumbent parts, glabrous. Leaves spirally arranged. Petiole 5–15 mm long, glabrous. Lamina 30–70 by 13–20, the leaves on the upper nodes are larger than on the lower nodes, narrowly elliptic to lanceolate, apex acute, base cuneate, margin crenate, glabrous, with 1 or 2 long hairs on each side of the midrib near the base, 1–1.5 mm long; lateral veins 4 or 5 pairs. Inflorescence axillary, erect, 1- or 2-flowered raceme. Peduncle 14–22 mm long, 1–1.5 mm diam, glabrous. Rachis 1–1.5 mm long. Flowers 30–38 mm long, 30–35 mm deep, rose pink. Bracts 2–3 by 1 mm, lanceolate to ovate, apex acute and mucronate, base cuneate, margin entire, without glands, glabrous, persistent. Pedicel 10–15 mm long, glabrous. Lateral sepals 2, 7–10 by 4–5.5 mm, free, ovate-lanceolate to lanceolate, apex acuminate and mucronate, base obtuse, pink, glabrous. Lower sepal 14–21 mm long, 13–18 mm deep, bucciniform, apex acute, deep pink, glabrous, distal part gradually constricted into a straight or curved spur, 25–30 mm long. Dorsal petal 11–13 by 10–11.5 mm, ovate to orbicular, cucullate

Map 21 Distribution of Impatiens andersonii Hook.f. (●), I. delicata Toppin (●) and I. gongshanensis Y.L.Chen (●).

to flat, apex obtuse, base cordate, glabrous, abaxial midvein with a slightly crescent-shaped crest. Lateral united petals 29–31 mm long, free: the upper petals 12–13 by 8.5–9 mm, obovate, apex truncate, base cuneate, pink; the lower petals 19.5–20 by 8.5–9 mm, free, ovate to obovate, apex obtuse to acute, base with distinct auricle, pink-yellow. Stamens: filaments c. 6 mm long. Ovary c. 5 mm long, c. 1.5 mm diam, glabrous. Fruits unknown. Seeds unknown.

Phenology — Flowering: October to December.

Distribution — Endemic to Myanmar (Kachin State).

Ecology — Growing in mossy areas of evergreen forest, c. 400 m altitude.

Other collections examined. MYANMAR, Kachin State, Jin et al. PT­ET 1276 (PE PE2472769*, PE PE2472770*), Putao, Machanbaw , N27°18'04.83" E97°35'08.61",alt. 420 m, 25 Oct.2014 ; Jin et al. PT­ET 20 (PE PE2472765*, PE PE2472766*, PE PE2472767*), Putao, Mularshidi , N27°15'17.29" E97°25'26.89", alt. 460 m, 11 Oct. 2014 .

Note — Impatiens delicata is similar to I. erubescens but differs in having a glabrous stem, instead of a pilose one. In the protologue, Toppin (1920) compared this species to I. pulchra and mentioned that I. delicata differs from I. pulchra by having 4 or 5 lateral veins. However, we found that it is easier to distinguish I. delicata by its pink instead of orange flowers and a straight or curved spur instead of a spiral one. We found two sheets of Toppin 4287. We select K000694679 as a lectotype because it is more complete and include dissected flowers.