Impatiens radiata Hook.f.

Smets, E. F. & Janssens, S. B., 2018, Balsaminaceae of Myanmar, Blumea 63 (3), pp. 199-267 : 220

11. Impatiens radiata Hook.f. — Map 7

Impatiens radiata Hook.f. (1875) 476; C.B. Clarke (1877) 137; Delavay (1889) 122; Höck (1909) 475; Biswas (1966) 210; H. Hara (1966) 196; H.Hara & L.H.J.Williams (1979) 80; S. Akiyama et al. (1995) 159; W.J. Kress et al. (2003) 170; Y.L. Chen et al. (2007) 77. — Impatiens radiata Hook.f. & Thomson in Hook.f. (1905) 15; Diels (1912) 222; Wu (2006) 97. — Type: Hooker s.n. (lecto, designated in Akiyama (2018) K K000694747; isolecto K K000694746), India, Sikkim, Lachung, alt. 6000–12000 ft, 6 July 1849.

Terrestrial, annual herb, 40–80 cm tall. Stem erect or decumbent in the lower part, heavily branched, glabrous. Leaves spirally arranged. Petiole 1–25 mm, glabrous. Lamina 55–140 by 20–60 mm, elliptic to ovate to lanceolate, apex acuminate, base cuneate, margin crenate with small teeth, papyraceous, green with red margin, remotely pilose, one distinct gland at the petiole base; lateral veins 7–9 pairs. Inflorescence axillary to subterminal, erect, verticillate, many-flowered raceme, radiate, 2–4-flowered per node. Peduncle 20–50 mm long, green and red, glabrous. Rachis 70–90 mm long. Flowers 20–22 mm long, 27–33 mm deep, white to pale pink. Bracts 6–8 by

Map 7 Distribution of Impatiens radiata Hook.f. (●), I. graciliflora Hook.f. (●), I. margaritifera var. humilis Y.L.Chen (●) and I. casseabriae Y.H.Tan, S.S.Zhou & B.Yang (●).

1–2 mm, broadly lanceolate, apex aristate with a gland, base obtuse, margin entire, green with red at apex, glabrous, persistent. Pedicel 17–25 mm long, red, glabrous. Lateral sepals 2, 2–4 by 1.5–2 mm, free, obliquely ovate, apex aristate, base obtuse, dark pink, glabrous. Lower sepal 4–8 by c. 1 mm, 2–2.5 mm deep, navicular, apex mucronate, white or pink, glabrous, distal part gradually narrow into a straight spur, 17–24 mm long. Dorsal petal 5–5.5 by 4–5.5 mm, orbicular, cucullate, apex mucronate to aristate, base obtuse, white or pink, with red midrib, glabrous, abaxial midvein simple or with a narrow crest terminating in a short acute point. Lateral united petals 13–14 mm long, free: the upper petals 2.5–4 by 3 mm, ovate to obovate, apex round to truncate, base cuneate, white or pink; the lower petals 7–12 by 3–4 mm, free, ovate to oblong, apex acute, white or pink, glabrous. Stamens: filaments c. 4 mm long, white; anthers white. Ovary 4–4.5 mm long, c. 1 mm diam, 5-carpellate, green, glabrous. Fruits up to 16 mm long, 3 mm diam, linear, 5-lobed, glabrous; fruiting pedicels 21–26 mm long, <1 mm diam. Seeds unknown.

Phenology — Flowering: July to December; fruiting: October to December.

Distribution — Myanmar (Chin State, Mandalay Region), Bhutan (Bumthang district), China (Yunnan Province), India (Meghalaya, Sikkim, west Bengal State), Thailand (northern Thailand).

Ecology — Growing among grass in open areas within the evergreen forest, 1800–3700 m altitude.

Other collections examined. MYANMAR, Chin State, U Mg Gale­2 5762 ( RAF8274 /2 sheet 1 & 2), Kanpetlet Dist., Esaken , alt. 5700 ft, 5 Sept. 1962 ; Murata et al. 024564 ( QBG QBG61252 ), Natma Taung National Park, at the foot of Mt Victoria , alt. 1800–2000 m, 2 Dec. 2002 ; Kingdon­Ward 22649 (BM), ibid., alt. 6000 ft, 2 Sept. 1956 ; Fujikawa et al. 053432 ( QBG QBG62063 ), N21°12'45.4" E94°1'15",alt. 2260 m, 12 Aug. 2008 ; Ling Shein Man 055281 ( QBG QBG78573 ), Natma Taung National Park , 2 Aug. 2007 ; Fujikawa et al. s.n. ( MBK086951 ), 3–4 miles from the entrance of National Park, Natma Taung National Park , alt. c. 2200 m, 21 Feb. 2012 ; Ling Shein Man 087637 ( QBG QBG61275 ), Old Town area, Kanpetlet Township , alt. c. 1750 m, 23 Oct. 2011 ; Mu Mu Aung et al. 092311 ( QBG QBG70765 ), N21°23.790' E93°50.366', alt. 2330 m, 3 July 2013 .

Note — Impatiens radiata is very similar to I. graciliflora but differs in having a shorter spur, 17–24 mm long vs 30 mm long.