Impatiens racemosa DC.

Smets, E. F. & Janssens, S. B., 2018, Balsaminaceae of Myanmar, Blumea 63 (3), pp. 199-267 : 221-223

15. Impatiens racemosa DC. — Map 8; Plate 2a

Impatiens racemosa DC. (1824) 688; D. Don (1825) 203; Wall . (1831) 167; Hook.f.(1875) 479;(1904b) 6; (1905) 16, 31; Craib (1926b) 213;T. Shimizu (1970) 190; Y.L. Chen et al. (2007) 57. — Type: Wall . Cat . s.n. (lecto, designated here G G00218030*), Nepal, 1821.

Impatiens racemosa DC. var. ecalcarata Hook.f.(1904b) 9, syn. nov. — Type: Prain 39I (lecto, designated here K K000694752), India, Sikkim Himalaya .

Impatiens microsciadia Hook.f. (1905) 16. — Type: Pantling s.n. (lecto, designated here K with illustration by Hooker), Sikkim, alt. 6000 ft

Terrestrial, annual herb, 30–90 cm tall. Stem erect, 2.5–6 mm diam, simple to richly branched, glabrous, with some globular glands on the ridge. Leaves spirally arranged. Petiole 5–15 mm long, glabrous. Lamina 55–120 by (15–) 32–40 mm wide, elliptic to ovate to lanceolate, apex acuminate to acute, base cuneate to attenuate, margin crenate, papyraceous, adaxial green, abaxial pale green, glabrous, with a pair of globular glands at the petiole base; lateral veins 7–10(–12) pairs. Inflorescence axillary, erect, 7–13(–19)-flowered raceme. Peduncle (20–)40– 50(–90) mm long, glabrous. Rachis (20–)30–40(–60) mm long. Flowers 7–11 mm long, 10–21 mm deep, yellow with red dots at lateral petals base. Bracts 1–2(–4) by 1 mm, ovate to lanceolate, apex mucronate to aristate, base cuneate, margin entire, glabrous, persistent. Pedicel 10–16 mm long, glabrous. Lateral sepals 2, 1.5–2 by 1.5–2 mm, free, ovate to obliquely ovate, apex mucronate to aristate, 2 mm long, base obtuse, green, glabrous. Lower sepal 3–7 mm long, 1.5–3 mm deep, navicular, apex mucronate to aristate, 2 mm long, glabrous, distal part gradually narrowing into a recurved to straight spur, 11–17 mm long, yellow. Dorsal petal 3.5–5 mm long, obovate, apex obtuse, base obtuse, glabrous, abaxial midvein simple or with narrowly crescent-shaped crest. Lateral united petals free: the upper petals 2–5 by 1.5–3 mm, ovate to orbicular, apex obtuse, base cuneate, yellow with red dots at the base; the lower petals free, 6–14 by 4–7 mm ovate, apex obtuse, base without auricle, yellow with red dots at the base. Stamens: filament green to yellow; anther yellow to white. Ovary green, glabrous. Fruits 12–17 mm long, 2–2.5 mm diam, linear, 5-lobed, glabrous. Seeds 2 mm long, obovoid, compressed.

Phenology — Flowering: July to November; fruiting: September to December.

Distribution — Bhutan, China (Tibet and Yunnan Province), India (Sikkim and Uttarakhand State), Myanmar (Chin, Kachin, Mandalay, Shan), Nepal (Dhaulagiri Zone, Dhawalagiri Zone, Gandaki Zone, Janakpur Zone, Koshi Zone, Mechi Zone, Sa- garmatha Zone), northern Thailand.

Ecology — Growing in open or shady areas in deciduous to evergreen forest, 1700–2300 m altitude.

Other collections examined. MYANMAR, Chin State, Huk s.n. (K H2015/00092

39), Chin Hills , July 1892 ; Venning 132 (K sheet 1, 2, 3) , Chin Hills, Sihaung road, 2 miles from Haka, alt. 7500 ft, 11 Oct. 1910 ; Murata et al. 024574 ( QBG024574 ), Natma Taung National Park, at the foot of Mt Victoria , alt. 1800–2000 m, 2 Dec. 2002 ; Ling Shein Man 055282 ( QBG QBG78499 ), Natma Taung National Park , 2 Aug. 2007 ; Ling Shein Man 087645 ( QBG QBG61278 ), Old Town area, Kanpetlet Township , alt. c. 1750 m, 23 Oct. 2011 ; Fujikawa et al. 090548 ( QBG QBG70760 ), N21°12'10.5" E94°01'47.1", alt. 1945 m, 4 Dec. 2012 ; Fujikawa et al. 094011 ( QBG), N21°12'22.3" E94°01'26.5", alt. 2075 m, 20 Aug. 2013 ; Funakoshi et al. 085068 ( QBG QBG61268 ), N21°12.162' E94°01.447',alt. 1955 m, 3 Sept.2011 ; Mandalay Region, Lace 6008 (E E00752884, K H2015/00092 38), Ruby mine district, Mogok & Bernarmyo, 25 Oct. 1912 ; Shan State, Ruchisansakun et al. 732 (L L2071119, MAND, RAF, RANG), Taunggyi district, Pindaya , N20°58'49.53" E96°37'41.62", alt. 1909 m, 26 Sept. 2015 .

Notes — The spur length of flowers of I. racemosa varies from absent to 17 mm. Spurred and spurless flowers can be found on the same plant (Chiang Mai population, Thailand). Therefore, we do not to recognise I. racemosa var. ecalcarata as a distinct taxon.

De Candolle (1824) only mentioned that I. racemosa was collected in Napaulia by Wallich but did not specify the specimens. We designate the specimen GDC00218030 as the lectotype because it is a complete specimen and is deposited in the De Candolle Herbarium and matches the protologue.

Hooker (1904b) did not clearly designate the holotype of I. racemosa var. ecalcarata . We select the specimen Prain 39I (K000694752) as the lectotype because Hooker made illustrations and wrote I. racemosa var. ecalcarata on the sheet. Hooker (1905) mentioned only the locality and altitude for I. microsciadia but did not provide other information for the type. We found two sheets of this species from Sikkim, 6 000 ft altitude, Pantling s.n. (one with illustration and another one without illustration), annotated by Hooker. We select Pantling s.n. (K, with illustration) as the lectotype.