Impatiens casseabriae Y.H.Tan,S.S.Zhou & B.Yang

Smets, E. F. & Janssens, S. B., 2018, Balsaminaceae of Myanmar, Blumea 63 (3), pp. 199-267 : 221

14. Impatiens casseabriae Y.H.Tan,S.S.Zhou & B.Yang — Fig. 12; Map 7; Plate 1h

Impatiens casseabriae Y.H.Tan, S.S.Zhou & B.Yang in Yang et al. (2017) 104. — Type: Myanmar Exped. 248 (holo HITBC not seen; iso KUN not seen, RAF not seen), Myanmar, Kachin State, Putao, Hkakabo Razi National Park , N27°43'28" E97°51'9", alt. 1200 m, 28 Nov. 2014.

Terrestrial, annual, glabrous herb, 17–30 cm tall. Stem lower part erect to decumbent, upper part erect, richly branched, glabrous. Leaves spirally arranged. Petiole absent – 3 mm long, glabrous. Lamina 35–70 by 6–8 mm, narrowly elliptic to narrowly oblanceolate, apex acute, base cuneate, margin deeply sinuate, glabrous, adaxial green with red margin, abaxial pale green; lateral veins 10 or 11 pairs; without distinct extrafloral nectary glands on lamina base nor petiole. Inflorescence subterminal, erect, 1- or 2-flowered raceme. Peduncle 15–20 mm long, glabrous. Rachis 5 mm long. Flowers 30 mm long, 5 mm deep, white, slightly asymmetric. Bracts c. 3 by 1.5 mm, elliptic, apex acute and mucronate, base obtuse, margin entire, glabrous, persistent. Pedicel 10–12 mm long, glabrous. Lateral sepals 2, c. 3 by 2 mm, free, obliquely ovate, apex acute and mucronate, base obtuse, white to pale green, sometimes with red, glabrous apex. Lower sepal c. 9 mm long, 3–4 mm deep, navicular, apex acuminate and mucronate, white, glabrous, spurless. Dorsal petal c. 8 by 4 mm, ovate, cucullate, apex acute and aristate, base cuneate, glabrous, white, abaxial midvein simple. Lateral united petals 27–32 mm long, free: the upper petals 8–9 by 2.5–3 mm, obliquely ovate, apex acute, base cuneate, white-purple; the lower petals 25–30 by 4–6 mm, free, sickle-shaped to narrowly obovate, apex acute, white, base white with a yellow mark. Stamens: filaments c. 2.5 mm long, white; anthers white. Ovary c. 2–2.5 mm long, 1 mm diam, green, glabrous.

Phenology — Flowering: October.

Distribution — Endemic to Myanmar (Kachin State). So far only known from the type locality.

Ecology — Growing on wet rocks along a waterfall in evergreen forest.

Other collection examined. MYANMAR, Kachin State, Saw­Lwin 1067 (L 2 sheets, RAF, RANG), Hkakabo Razi National Park.

Note — Impatiens casseabriae is morphologically similar to I. margaritifera var. humilis but differs in having a shorter petiole, narrowly elliptic to narrowly oblanceolate longer lower petals.