Impatiens parishii Hook.f.

Smets, E. F. & Janssens, S. B., 2018, Balsaminaceae of Myanmar, Blumea 63 (3), pp. 199-267 : 212-214

3. Impatiens parishii Hook.f. — Fig. 8; Map 4

Impatiens parishii Hook.f. (1875) 456; (1905) 30; Craib (1926b) 212; T. Shimizu (1970) 189; W.J. Kress et al. (2003) 170. — Type: Parish s.n. (lecto, designated here K K000694782), Myanmar, Moulmein, Tenasserim, 1862.

Fig. 8 Impatiens parishii Hook.f. a. Habit; b. front view of flower; c. lateral view of flowers; d. upper lateral sepals; e. lower lateral sepals; f. lower sepals; g. dorsal petal; h. lateral united petals; i. stamens; j. ovary. — Drawn by Saroj Ruchisansakun.

Lithophytic, caudiciform perennial, glabrous herb, 45–100 cm tall. Stem erect, cylindrical, c. 15 mm diam, richly branched, green when young and grey on lower parts, marked with old leaf scars on the lower part. Leaves spirally arranged. Petiole 55–75 mm long, c. 3 mm diam, green. Lamina 135–210 by 70–95 mm, ovate to ovate-lanceolate, apex acuminate, base round to obtuse to attenuate, sometimes unequal, coriaceous, margin serrate, with a gland on each side of the margin at the base; lateral veins 7–10 pairs, green. Inflorescence axillary, pendulous, solitary. Flowers 32–40 mm, 13–15 mm deep, slightly asymmetric, white to pale pink, with yellow mark on the lower petals. Bracts c. 5 by 1.5 mm, lanceolate, apex acute, base cuneate, margin entire, green, persistent. Pedicel 20–40 mm long, c. 1.5 mm diam, cylindrical, pale green. Lateral sepals 4, free; the lower pair c. 12 by 11 mm, free, orbicular to ovate, apex acute to acuminate and mucronate, base obtuse, white to pale pink: the upper pair 1–1.5 mm long, ovate. Lower sepal 13–23 by 16–18 mm, 6–8 mm deep, navicular, apex acuminate, base obtuse, white to pale pink, distal part abruptly constricted into gourd spur and slightly bifid at apex, c. 5 mm long. Dorsal petal c. 12 mm long, elliptic, cucullate, apex round and mucronate, base obtuse, abaxial midvein with a narrow crest terminating in a short acute point. Lateral united petals 35–36 mm long, connate: the upper petals 17–18 by 9–10 mm, obovate, apex truncate, base cuneate, white; the lower petals 27–29 by 9–10 mm, connate, elliptic to obovate, apex obtuse, white with yellow mark at the base. Stamens: filaments c. 10 mm long, white; anthers yellow. Ovary 7–8 mm long, c. 2 mm diam, 4-carpellate, green; ovules, in 2 rows per locule, 3–5 ovules per row. Fruits 24 mm long, 6 mm diam, clavate, 4-lobed. Seeds unknown.

Phenology — Flowering: June to October; fruiting: August to November.

Distribution — Southern Myanmar (Mon State), northern and north-western Thailand.

Ecology — There is no information on the ecology of this species for Myanmar. In Thailand, it grows on limestone in lowland forest, sometimes in shady areas near waterfalls, 300–1000 m altitude.

Note — Impatiens parishii is very similar to I. kerriae but differs in having a shorter pedicel than petiole, four lateral sepals instead of two, wavy red streaks on the lower lateral united petals rarely present while always present and showy in I. kerriae . Shimizu (1970) mentioned that the spur of I. parishii is not bilobed, whereas I. kerriae has a deeply bilobed spur, however, we found that this character is variable within both species. Impatiens parishii usually grows at around 500 m altitude while I. kerriae grows at around 1500 m altitude.