Impatiens austroyunnanensis S.H.Huang

Smets, E. F. & Janssens, S. B., 2018, Balsaminaceae of Myanmar, Blumea 63 (3), pp. 199-267 : 225-226

17. Impatiens austroyunnanensis S.H.Huang — Fig. 13; Map 8

Impatiens austroyunnanensis S.H.Huang in Huang et al.(2003) 262,276. — Type: Shui Yu­Min 003306 (holo YUKU not seen), China, Yunnan Province, Wemshan, Laojunshan , alt. 2450 m, 5 Aug. 1993; Wu et al. 3065 (para KUN KUN0772011*), Wu et al. 3438 (para KUN KUN0772012*), Wu et al. 3753 (para KUN KUN0772011*), China, Yunnan Province, Jinping , Maandi , Wutaishan , alt. 2400–2700 m, 10 Sept. 1996 .

Terrestrial, perennial herb, with procumbent rhizome, 15–20 cm tall. Stem erect to decumbent, up to 4 mm diam, moderately branched, green to purple, glabrous. Leaves decussate or spirally arranged. Petiole absent– 5 mm long, c. 1 mm diam, glabrous. Lamina c. 43 by 13 mm, elliptic to obovate, apex acute, base obtuse, margin slightly serrate, adaxial green, abaxial pale green, glabrous, with one pair of glands on lamina base; lateral veins 3 or 4 pairs. Inflorescence axillary to subterminal, erect, 2–4-flowered raceme. Peduncle 7 mm long, <1 mm diam, green with purple dots, glabrous. Rachis 5 mm long, green, glabrous. Flowers 20–25 mm long, 15–20 mm deep, asymmetric, yellow to purple. Bracts c. 5 by 2 mm, lanceolate, apex acute and mucronate, base cuneate, margin entire, without glands, pale green, glabrous, persistent. Pedicel 20 mm long, <1 mm, pale green to purplish green, glabrous. Lateral sepals 2, 3 by 1.5 mm, free, obliquely lanceolate, apex acute and mucronate, base obtuse, glabrous. Lower sepal 7 mm long, 17 mm deep including spur, deeply bucciniform, protruding upward, apex acute and mucronate, pale pink, glabrous, distal part elongate as spur, dilated at middle. Dorsal petal c. 7 by 7 mm, broadly ovate, flat, apex acuminate and mucronate, base round, pale pink, glabrous, abaxial midvein simple. Lateral united petals 24–28 mm long, free, slightly different in shape between both sides, the left one slightly longer than the right one: the left upper petal c. 5 by 3 mm, broadly ovate to triangular, apex acute, base cuneate, purple to yellow; the right upper petal c. 6 by 2–3 mm, broadly ovate to triangular, apex acute, base cuneate; the lower petals free; the left lower petal c. 24 by 2 mm, narrowly oblong, apex acute to obtuse, base distinctly yellow auricled, purple, glabrous; the right lower petal shorter, c. 19 by 3 mm, narrowly oblong, apex acute to obtuse, base yellow with a distinct auricle. Stamens c. 4 mm long. Ovary 3 mm long, 1 mm diam, green, glabrous. Fruits linear, green, glabrous. Seeds unknown.

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

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

Ecology — Growing in shady areas in evergreen forest, 2400–2800 m altitude.

Other collections examined. MYANMAR, Kachin State, Kingdon­Ward 7443 (K), Valley of the Senghku , N28°05' E97°30', 8000–9000 ft, 21 Sept. 1926 ; Kingdon­Ward 7459 (K), ibid., 25 Sept. 1926 ; Saw­Lwin KSL1065 (L), Hkakabo Razi National Park , 23 Oct. 2015 .

Notes — Impatiens austroyunnanensis was previously only poorly known. Some specimens in PE and KUN were identified as I. microcentra . However, they are very different from the description in the protologue ( Handel-Mazzetti 1933: 653) and the holotype of I. microcentra, Handel­Mazzetti 9244 (WU0059594), in having a shorter stem, longer peduncle, deeply bucciniform lower sepal (instead of cylindrical lower sepal), c. 17 mm deep lower sepal including spur (instead of a 5 mm deep sepal), narrowly oblong lower lateral petals (instead of ovate to obovate lateral petals) (Table 3). This confusion is possibly due to the fact that Chen in 1973 annotated Yu 20313 (PE00039564, PE00039565) as a ‘topotype’; mentioning this on the specimen sheets; subsequently this led to the use of the wrong illustration in later publications ( Akiyama et al. 1995: 158, Wu 2006: 80, 127, Chen et al. 2007: 50, 71). The index Florae Yunnanensis and Vascular Plants of the Hengduan Mountains refer to the type

Fig. 13 Impatiens austroyunnanensis S.H.Huang flower; c. lateral view of flowers; d. lateral sepals petal; g. lateral united petals. — Drawn by Saroj specimens only, so there is no mistake in that publication (Wu 1984: 303). In Flora of China ( Chen et al. 2007), I. austroyunnanensis was not treated because the authors did not see any herbarium specimens.

Impatiens austroyunnanensis is most similar to I. holocentra but differs in having a deeply bucciniform spur that dilates in the middle.