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| Impatiens subfalcata Soulad. & Tagane in Souladeth, Tagane, ... et Souvannakhoummane, 2021. ທຽນໃບດາບ || twitter.com/EJBotany |
ABSTRACT
Impatiens subfalcata Soulad. & Tagane, a new species of Balsaminaceae from southern Laos, is described and illustrated. The new species is morphologically similar to Impatiens attopeuensis and I. notoptera in having succulent stems, serrate leaf margins and pinkish flowers, but distinguished from these two by its falcate lanceolate or oblanceolate leaves, more numerous secondary veins, shorter petioles and smaller dorsal petals.
Keywords: Balsaminaceae, Bolaven Plateau, Impatiens, Laos, new species, taxonomy
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| Impatiens subfalcata Soulad. & Tagane. A and B, Habitat (individuals indicated by red arrow); C, habit; D, portion of lower leaf surface; E, leaves; F, flower bud; G, flower (front view); H, flower (lateral view); I, spur; J, petals; K, fruit; L, seeds. Scale bars (yellow): E, 5 cm; F, I and J, 1 cm; L, 2 mm. All photographs from Souladeth et al. L2492. Photographs: S. Tagane |
Impatiens subfalcata is easily recognised by its slightly falcate and lanceolate or oblanceolate leaves (length-to-width ratio, 4.6–7.6). In Laos, it is similar to Impatiens attopeuensis Hook.f. in its habit, serrate leaf margins and pinkish purple corolla, but distinguished not only by its slightly falcate leaves but also by its more numerous secondary veins (8–10 pairs in I. subfalcata versus 5–7 pairs in I. attopeuensis), shorter petioles (subsessile to 0.2 cm long versus 0.5–2 cm long), shorter spur (2.1–2.6 cm versus 4–7 cm long), and smaller dorsal petal (6–7 mm versus 12–14 mm).
Distribution. Laos, Champasak Province, Dong Hua Sao National Protected Area (Bolaven Plateau), 1147 m elevation.
Habitat and ecology. Impatiens subfalcata grows on dripping rocky walls at a waterfall.
Etymology. The species epithet, subfalcata, is derived from the slightly falcate nature of the leaves of this species.
Vernacular name. ທຽນໃບດາບ (thien bai dab), suggested here; in Lao, thien means Impatiens species and bai dab means ‘falcate leaf’.
P. Souladeth, S. Tagane, Y. Suyama, N. Ishii, A. Nagahama and K. Souvannakhoummane. 2021. Impatiens subfalcata (Balsaminaceae), A New Species from Laos. EDINBURGH JOURNAL OF BOTANY. 78; DOI: 10.24823/EJB.2021.358
