Impatiens kamtilongensis Toppin, 1920

Smets, E. F. & Janssens, S. B., 2018, Balsaminaceae of Myanmar, Blumea 63 (3), pp. 199-267 : 253-254

60. Impatiens kamtilongensis Toppin — Map 20

Impatiens kamtilongensis Toppin (1920) 356; W.J. Kress et al. (2003) 170. — Type: Toppin 4275 (lecto, designated here K K000694653; isolecto K K000694654, K K000694655), Myanmar, Kamtilong Hills and Kachin Hills, Kumtat, Sinar. Dec. 1911.

– non S. Akiyama et al. (1996) 135; Y.L. Chen et al. (2007) 50, 93; V.T. Chinh et al. (2015) 332.

Terrestrial, annual herb, 13–28 cm tall. Stem erect to decumbent in the lower part, 3.2–5 mm diam, unbranched to rarely branched at the decumbent part, pilose to densely pilose towards apex. Leaves spirally arranged. Petiole 11.5–26 mm long, 1–1.5 mm diam, densely pilose, sometimes with 1 or 2 pair(s) of glandular hairs on petiole. Lamina 45–110 by 27–45 mm, elliptic to elliptic-obovate, apex acute to acuminate, rarely round, base attenuate, margin crenate to slightly serrate, densely pilose on both sides, with 1 or 2 pair(s) of long hairs on the margin near lamina base; lateral veins 7 or 8 pairs. Inflorescence axillary, erect, 1- or 2-flowered raceme. Peduncle 7 mm long, 1 mm diam, densely pilose. Rachis 4–4.5 mm long, c. 1 mm diam, densely pilose. Flowers 23 mm long, 23 mm deep, pink. Bracts 2–2.5 mm long, linear, apex acute, base cuneate, margin entire, without glands, densely pilose, persistent. Pedicel 12.5–16 mm long, 0.5 mm diam, densely pilose. Lateral sepals 2, 9–11 by 4–5 mm, free, ovate to elliptic, apex acuminate to acute and mucronate, base obtuse to cuneate, densely pilose. Lower sepal 3.5–19 mm long, 8–14 mm deep, bucciniform, apex acuminate and mucronate, densely pilose, distal part abruptly constricted into an incurved spur, sometimes with spiral end, 21–26 mm long. Dorsal petal 10–12.5 by 7–8 mm, obovate, cucullate, apex emarginate, base obtuse to cuneate, pink, densely pilose on the midrib, abaxial midvein with an acute appendage, 2.5–4 mm

Map 20 Distribution of Impatiens khasiana var. khasiana Hook.f. (●), I. khasiana var. toppinii (Dun) Ruchis. & Suksathan (●), I. kamtilongensis Toppin (●) and I. lacei Hook.f. (●).

long. Lateral united petals 18–25 mm long, free, pink: the upper petals 12.5–14 by 6–7 mm, broadly oblanceolate, apex truncate, base cuneate, pink; the lower petals 10–13.5 by 7–10 mm, free, ovate to broadly elliptic, apex round, base with distinct auricle, rounded, pink, glabrous. Stamens: filaments 5–5.5 mm long. Ovary 5–5.5 mm long, 1–1.5 mm diam, glabrous to scabrous. Fruits 14.5 mm long, 4 mm diam, long fusiform, glabrous to scabrous, green; pedicels at fruiting stage c. 15 mm long. Seeds unknown.

Phenology — Flowering: December; fruiting: December.

Distribution — Endemic to Myanmar (Kachin State).

Ecology — Growing in wet and shady areas of evergreen forest, 500–650 m altitude.

Notes — Impatiens kamtilongensis is very similar to I. khasiana and I. porrecta but differs in having a dorsal sepal with an acute appendage, instead of a crescent-shaped crest or keel-shaped crest, on the abaxial side of the dorsal petal.

Although Toppin (1920) mentioned that I. khasiana and I. kamtilongensis have different flower colours, dried flowers on the type specimens of both taxa are pink. In the description of I. kamtilongensis, Toppin (1920) states “ Flores pallide sufflavi vel fere albi” (flowers yellowish or almost white), but this possibly refers to the colour of the lower sepal, not to the colour of the whole flower.

Akiyama et al. (1996), Chen et al. (2007) and Chinh et al. (2015) mention I. kamtilongensis as having yellow flowers, hence, we suspect that the specimens they refer to do not belong to this taxon in our sense.

Three sheets of the type specimen of I. kamtilongensis, Toppin 4275, were found. We select K000694653 as a lectotype because it is a complete specimen with dissected flowers.