Impatiens peguana Hook.f.

Smets, E. F. & Janssens, S. B., 2018, Balsaminaceae of Myanmar, Blumea 63 (3), pp. 199-267 : 243-244

46. Impatiens peguana Hook.f. — Fig. 17; Map 16

Impatiens peguana Hook.f.(1905) 29,34; Fedde (1905) 433; W.J. Kress et al. (2003) 170. — Type: M’Clelland s.n. (lecto,designated here K K000694711), Myanmar, Pegu.

Annual herb, 11–21.5 cm tall. Stem erect, c. 2 mm diam, cylindrical, unbranched, glabrous. Leaves decussate. Petiole 7–21 mm long, c. 1 mm diam, glabrous. Lamina 42–48 by 22–26 mm, ovate, apex acute, base obtuse to round and attenuate, margin shallowly crenate with small teeth, adaxial glabrous, abaxially pilose, with 1–3 pair(s) of long hairs near lamina base, up to 1.5 mm long; lateral veins 5 or 6 pairs. Inflorescence axillary, erect, 4–6-flowered raceme. Peduncle 32–42 mm long, c. 0.5 mm diam, glabrous. Rachis 4–6 mm long, <0.5 mm diam. Bracts 1.5–2 by c. 1 mm, ovate, apex acuminate and mucronate, base obtuse, glabrous, persistent. Pedicel 2–5 mm long, <1 mm diam, glabrous. Lateral sepals 2, c. 2 by 1.6 mm, free, broadly ovate to orbicular, apex round and mucronate, base round, glabrous. Lower sepal c. 3.5 mm long, 1 mm deep, navicular, apex mucronate, glabrous, spurless. Dorsal petal c. 2 by 2.5 mm, broadly elliptic, cucullate, apex round and mucronate, base obtuse, glabrous, abaxial midvein simple. Lateral united petals 7–8 mm long, free: the upper petals 1.5–2 by 0.5 mm, falcate, apex acute, base cuneate; the lower petals 6–7 by 2.5–3 mm, free, obovate, apex round, base without auricle, glabrous. Ovary c. 2 mm long.

Phenology — Unknown.

Distribution — Endemic to Myanmar (Bago Region).

Ecology — Unknown.

Notes — Impatiens peguana was included in I. circaeoides in the Flora of British India ( Hooker 1875), but Hooker later decided to describe it as a new species ( Hooker 1905: 34). It is very similar to I. circaeoides , I. rangoonensis and I. tavoyana and no differences can be found in vegetative morphology, based on the Hooker (1905) description that includes details on leaf arrangement. Impatiens peguana differs from the three above-mentioned species in having a spurless lower sepal and broadly ovate to orbicular lateral sepals. The authors have not seen living plants or any additional specimens beyond the type specimen. Consequently, the current description is based on the type. Hooker did not include a detailed description in the protologue ( Hooker 1905).

Since Hooker did not designate a type, we select M’Clelland s.n. (K000694711), the only specimen we found with the name I. peguana and illustration, as lectotype.