Hydrocera triflora

Smets, E. F. & Janssens, S. B., 2018, Balsaminaceae of Myanmar, Blumea 63 (3), pp. 199-267 : 207-209

1. Hydrocera triflora (L.) Wight & Arn. — Map 3; Plate 1a

Hydrocera triflora (L.) Wight & Arn. (1834) 140; Wight (1837) 4; Steud. (1840) 804, 805; (1841) 727; Meisn. (1843) 42; Prain (1903) 297; Hook.f. (1904a) 27, 31, 32; F. Lewis (1919) 144; Bose (1920) 198; Merr. (1921) 363; Venkat. & B.S.M.Dutt (1961) 545; Amaratunga (1970) 455; V. Singh (1971) 340; Grey-Wilson (1980b) 21; K. Hou (1982) 240; Ramadevi & L.L.Narayana (1990) 43; Tan et al. (1992) 128;I.M. Turner (1993) 44; (1995) 146; I.M. Turner et al. (1994) 2, 12; Chew et al. (1997) 174; W.J. Kress et al. (2003) 169; Wu (2006) 67. — Impatiens triflora L. (1753) 938; G. Don (1831) 750; Steud. (1840) 804, 805; Hook.f. (1904a) 27, 31. — Tytonia triflora (L.) C.E.Wood (1975) 413. — Type: Hermann Herb.3: 35, 315 (lecto, designated in Grey-Wilson (1980b) BM BM000621927).

Impatiens natans Willd.(1798) 1175;Roxb.& Carey (1824) 455;G. Don (1831) 749;Pidd. (1832) 45, 184; Roxb.(1832) 652; Steud.(1840) 804. — Tytonia natans (Willd.) G. Don (1831) 749; Steud. (1841) 727; Hook.f. (1904a) 27, syn. in Steudel (1840). — Type: Klein s.n. (lecto, designated here HAL HAL0118810*), India.

Hydrocera angustifolia Blume (1825) 241; Hook.f. (1911a) 629; Ridl. (1922) 340, syn. in Grey-Wilson (1980b). — Impatiens angustifolia Blume (1823) 49. — Balsamina angustifolia Blume (1825) 239. — Type: Wight s.n. (lecto, designated here K K000741571).

Semi-aquatic perennial herb, 0.5–1.5 m tall. Stem up to 1.5 cm diam, annual, erect or decumbent below, moderately unbranched, angular, pale green to reddish green, the portion below the water whitish, glabrous, hollow. Leaves spirally arranged, sessile to very short. Petiole absent – 10 mm long, c. 5 mm diam, glabrous. Lamina 100–270 by 10–45 mm, narrowly lanceolate to narrowly elliptic, apex acute, base cuneate to attenuate, margin serrate, papyraceous, adaxial dark green, abaxial pale green, glabrous, with one pair of glands at the base margin; lateral veins 10–12 pairs. Inflorescence axillary, pendulous to horizontal, 2–5-flowered raceme. Peduncle up to 20 mm long, c. 2 mm diam, angular, winged, green to red, glabrous. Rachis 5–8 mm long, c. 1 mm diam. Flowers c. 30 mm long, 20–25 mm wide, 20–25 mm deep, pink and red with yellow markings at the centre of lower sepal. Pedicel 10–30 mm long, 1–1.5 mm diam, white to green to red, glabrous. Bracts 5–9 by 1–2.5 mm, oblong to lanceolate to narrowly ovate, apex acute to acuminate, base cuneate, margin entire, green to red, glabrous, caducous. Lateral sepals 4: the upper pair 12–14 by 6–7.5 mm, ovate to obovate, apex obtuse, base cuneate, pale pink, glabrous to remotely pilose; the lower pair 15–19 by 8–12 mm, free, elliptic to obovate, concave, apex acute to obtuse and mucronate, base cuneate to obtuse, pale pink, glabrous to remotely pilose. Lower sepal 12–20 mm long, 7–9 mm wide, 8–17 mm deep, bucciniform, apex acute to acuminate, base obtuse, dark red with yellow mark at the centre inside, glabrous to remotely pilose, abruptly constricted into an incurved spur, 5–13 mm long, 1 tip, swollen, green. Dorsal petal 12–18 by 11–20 mm, broadly elliptic, slightly cucullate, apex round and mucronate, base cuneate, pale pink, sometimes semipellucid, glabrous to remotely pilose outside. Upper lateral petals 13–15 by 8–9 mm, obovate, apex round, base obtuse to cuneate, pale pink with dark red line at the centre. Lower lateral petals 2–3 by 5–8 mm, free, obovate to oblong, apex round to obtuse, base with distinct auricle, dark red, glabrous. Stamens: filaments, 7–10 mm, white to pale pink; anthers connate, pink. Ovary 7–10 mm long, 1–2 mm diam, 5-locular, green, glabrous. Fruits 9–15 mm long, 9–13 mm diam, pseudoberry, globose, slightly 5-lobed, green to deep red, glabrous.

Phenology — Flowering: June to August; fruiting: June to September.

Distribution — Myanmar (Mon State, Shan State), India (Bengal, Madras), Ceylon, southern China (Hainan), Cambodia, Laos, Malay Peninsula, SW Celebes, Java.

Ecology — Ditches, marshy places, stagnant pools and rice paddies, 0–100 m altitude.

Other collections examined. MYANMAR, Mon State, Ruchisansakun & Thet Yu New 714 (L L2071076, RAF), Mawlamyine, Kalagon , N16°32'00.29" E97°42'53.85", alt. 39 m, 20 Aug. 2015 ; Shan State, Dewan Mohinder Nath Nair & U Maung Pyone 1563 ( RANG RANG2460 ), in Phaw Kone village, Inie lake , 2 May 1957 .

Notes — Hydrocera is distinctly different from Impatiens by its berry-like instead of dehiscent fruit and five free petals instead of lateral united petals.

We select Klein s.n. ( HAL0118810 ) as lectotype because it was verified by Willdenow and deposited in Halle, Germany, where he worked before the protologue was published ( Tkach et al. 2016) .

II. Impatiens Riv. ex L.

Impatiens Riv. ex L. (1753) 937; (1754) 403; DC. (1824) 687;Roxb.& Carey (1824) 452;Roxb. (1832) 651; Wight & Arn.(1834) 135; Hook.f.& Thomson (1860) 118; Hook.f. (1875) 440; Vivek. et al. (1997) 99; Y.L. Chen et al. (2007) 43. — Type: Impatiens noli­tangere L. (1753) 938.

Balsamina Tourn. ex Scop. (1772) 183; Mill. (1754) without page numbers. — Balsamina Tourn. (1719) 418, synon in Druce (1913) 429. — Type: Balsamina noli­tangere Scop. (1772) 184.

Chrysaea Nieuwl. & Lunell in Lunell (1916) 473. — Chrysaea Cusa in Daléchamps (1587) 876. — Type: Chrysaea biflora Nieuwl. & Lunell in Lunell (1916) 473.

Impatientella H. Perrier (1927) 22; A.W. Hill (1938) 144, 303. — Type: Impatientella inaperta H. Perrier (1927) 22.

Petalonema Peter (1928) 84; Brenan (1945) 213. syn. in Schulze (1935). — Type: Petalonema fissibracteum Peter (1928) 84.

Semeiocardium Zoll.(1858) 245; Backer (1935) 70; Grey-Wilson (1989a) 107; Utami (2009) 22; S.X.Yu et al. (2015) 13; Ruchis. et al. (2015) 1063, syn. in Grey-Wilson (1989a). — Type: Semeiocardium arriensii Zoll.(1858) 245.

Trimorphopetalum Baker (1887) 454; Eb.Fisch. & Raheliv. (2002) 279, syn. in Fischer & Rahelivololona (2002). — Impatiens subg. Trimorphopetalum (Baker) Eb.Fisch. (2002) 279. — Type: Trimorphopetalum dorstenioides Baker (1887) 455.

Terrestrial, lithophytic or epiphytic, perennial or annual, herbs or rarely shrubs. Stem erect or procumbent, usually succulent, often rooting at lower nodes. Leaves simple, arranged spirally, decussate, or in whorls, petiolate or sessile. Petiole cylindrical or often flat. Lamina apex acute to acuminate, margin serrate or crenate, with mucronate teeth or with the teeth apices set in the sinus, papyraceous or coriaceous, often with glands at the base or on the petiole. Inflorescence axillary to terminal to subterminal, erect or pendulous, racemose or flowers solitary or in fascicles. Peduncle cylindrical or often angular. Flowers bisexual, zygomorphic or asymmetrical, mostly resupinate. Sepals 3 or 5. Lateral sepals 2 or 4: the upper pair reduced, or often absent; the lower pair always present, free or connate with each other. Lower sepal navicular, deeply navicular, bucciniform, deeply bucciniform, infundibular, to saccate, tapering or abruptly constricted into a spur. Dorsal petal flat or cucullate, abaxial midvein often with crest. Lateral petals on each side connate into ‘lateral united petals’ (wing petals): the upper petals mostly distinct, often reduced, usually smaller than the lower, mostly free, rarely connate with the opposite upper petal into a hood; the lower petals free or connate. Stamens: filaments lying close to ovary, flat; anthers connate. Ovary of 4 or 5 carpels. Fruit a fleshy dehiscent capsule.