Impatiens clavicuspis Hook.f. ex W.W.Sm.

Smets, E. F. & Janssens, S. B., 2018, Balsaminaceae of Myanmar, Blumea 63 (3), pp. 199-267 : 231

27. Impatiens clavicuspis Hook.f. ex W.W.Sm. — Map 11

Impatiens clavicuspis Hook.f. ex W.W.Sm. in Smith & Forrest (1915) 337; W.J. Kress et al. (2003) 169. — Type: Forrest 1004 (lecto, designated here K K000694594; iso E E00313653), China, Yunnan, between Mekong and Yongchang valleys on Tengyue-Dalifu road, N25°20', alt. 8000–9000 ft, Sept. 1905.

Annual herb, 30–60 cm tall. Stem erect, 2 mm diam, sparsely branched, glabrous with few glandular hairs on the ridges in upper part of stem. Leaves spirally arranged. Petiole 11.5–30 mm long, glabrous, with one pair of stipular glands at petiole base. Lamina 30–41 by 19–25 mm, ovate-lanceolate to lanceolate, apex acuminate, base cuneate to attenuate, margin crenate with teeth, glabrous, with 1 pair of glandular hairs near lamina base; lateral veins 4–6 pairs. Inflorescence axillary, erect, 8–17-flowered raceme. Peduncle 26–65 mm long, c. 1 mm diam, glabrous. Rachis 14.5–40 mm long, c. 1 mm diam, glabrous. Flowers 22–24 mm long, 25–32 mm deep, pale yellow with purple base. Bracts 3–7 by 1.5–2 mm, ovate to lanceolate, apex aristate with long glandular awn, base obtuse, margin entire, glabrous, persistent. Pedicel 11.5–12.5 mm long, <1 mm diam, glabrous. Lateral sepals 2, 3.5–5 by 2.5–4 mm, free, elliptic to obliquely elliptic, apex aristate with long awn, 1.5–2.7 mm long, base obtuse, glabrous. Lower sepal 11.5–16 mm long, 12–16 mm deep, bucciniform, apex aristate with long awns, 2–3 mm long, glabrous, distal part gradually narrowed into an incurved spur, 17–18 mm long. Dorsal petal 7.5–9 by 7–9 mm, ovate to elliptic to orbicular, cucullate, apex round and mucronate, base obtuse, glabrous, abaxial midvein with narrow crest, c. 1 mm high. Lateral united petals c. 22–27 mm long, free: the upper petals 10–11 by 6–7 mm, broadly elliptic, apex acute, base cuneate; the lower petals 13–19 by 3–3.5 mm, free, narrowly lanceolate to narrowly ovate, apex acute, base with distinct auricle, c. 2 mm high, glabrous. Stamens: filaments c. 5 mm long. Ovary c. 4 mm long, <1 mm diam, glabrous. Fruits 17 mm long, 1 mm diam, linear, glabrous; fruiting pedicels c. 18 mm long, straight.

Phenology — Flowering: September to October; fruiting: October to November.

Distribution — Myanmar (Kachin State), China (Yunnan).

Ecology — Understories of mixed forests, along canals, moist places, 2100–2800 m altitude.

Other collections examined. CHINA, Henry 9762 (syn K K000199723), Ducloux 432 (syn K K000199724), Yunnan . – MYANMAR, Forrest 1006 (syn K K000694595, E E00313652), upper Burma and N.W. Yunnan, the Ming- Kwong-Irrawadi divide, lat. N26°, alt. 7000–8000 ft, Oct. 1905 .

Note — Impatiens clavicuspis is similar to I. ceratophora but differs in having long-awned apices on bracts and lateral sepals vs acute to acuminate apices.