Impatiens kamtilongensis Toppin, Bull. Misc. Inform. Kew 1920: 356

Souvannakhoummane, K., Newman, M. F., Lanorsavanh, S. & Suksathan, P., 2021, Impatiens rostrata (Balsaminaceae), a new species from Khammouane Province, Laos, and nine new records, Edinburgh Journal of Botany 78 (362), pp. 1-15 : 8

Impatiens kamtilongensis Toppin, Bull. Misc. Inform. Kew 1920: 356 (1920); Akiyama, Ohba & Wu, Bull. Natl. Sci. Mus. Tokyo, B 22 : 135 (1996); Chen, Akiyama & Ohba, Fl. China 12: 50 (2007); Chinh, Huong, Quang & Suksathan, T ạp Chí Sinh H ọc 37: 332 (2015); Ruchisansakun et al., Blumea 63: 253 (2018).

– Type : Myanmar, Kamti Long Hills, Kumtat ; Sinar at 650 m, xii 1911, Toppin 4275 (lectotype K [ K000694653 ]; isolectotypes K [ K000694654 ], K [ K000694655 ] designated by Ruchisansakun et al., 2018). Figure 3G–I .

Impatiens finetii Tardieu, Notul. Syst. (Paris) 11: 183 (1944); Fl. Indo-Chine Suppl. 1, 4–5: 588 (1945), syn. nov. – Type: Vietnam, Thanh hao , Dat Kiet , 13 ix 1920, Poilane, E. 1842 (lectotype P! [ P00780719 ], designated here; isolectotypes P! [ P00780720 , P00780721 ]) .

Distribution. This species has been found at Phou Chom Voy, Khamkeut District, Bolikhamxai Province, Laos. It was originally described from central Myanmar ( Toppin, 1920) and has also been reported from China and Vietnam ( Chen et al., 2007; Chinh et al., 2015).

Habitat and ecology. Growing near streams, sandy soil in wet areas, in evergreen forest, associated with Begonia sp. ( Begoniaceae ), Odontochilus elwesii C.B.Clarke ex Hook.f. ( Orchidaceae ) and Araceae .

Phenology. Flowering from June to December, fruiting in December and January.

Specimens examined. LAOs. Bolikhamxai Province: Khamkeut District, Naheung village, Phou Chom Voy , 1200–1400 m altitude, 19 vi 2018, Lanorsavanh, Lamxay, Souvannakhoummane & Bounphanmy SL 1282 (Biology herbarium, Faculty of Natural Science, National University of Laos, FOF, HNL) ; ibid., 12 xii 2017, Lamxay s.n (Biology herbarium, Faculty of Natural Science, National University of Laos) .

Impatiens kamtilongensis is very closely related to I. porrecta Wall. ex Hook.f. & Thomson and I. khasiana Hook.f. by its spurred dorsal petal (versus cristate). This species was said by Ruchisansakun et al. (2018) to have pink flowers because of the very pale pink petals in the type specimen, which differs from the colour indicated in the protologue (yellowish white). We feel that the colour described in the text of the protologue is more reliable than what we have seen on a 100-year-old specimen. Our material varies from the type specimens by having yellow flowers (not yellowish white). This concept is also adopted in the Flora of China ( Chen et al., 2007).

Impatiens kamtilongensis also resembles I. wuchengyihii S.Akiyama, H.Ohba & S.K.Wu from South China morphologically but differs by the shape of the lateral sepals (ovate-lanceolate versus linear). It also differs from Impatiens phahompokensis T.Shimizu & Suksathan from Thailand by its inflorescences with 1 or 2 flowers versus solitary flowers, and its lateral sepals, which are ovate, not suborbicular.

Figures

Figure 3. A–C, Impatiens damrongii: A, plant with flower; B, lateral view of bud; C, partial front view of flower. D–F, Impatiens drepanophora: D, plant with flowers; E, raceme and lateral view of flowers; F, oblique view of flowers. G–I, Impatiens kamtilongensis: G, plant with flower; H, front view of flower; I, lateral view of flower. Scale bars: 1 cm. Photographs: A–C, K. Phoutthavong; D–F, K. Souvannakhoummane; G–I, S. Lanorsavanh.