Impatiens lobbiana Turcz., Bull. Soc. Imp. Naturalistes Moscou

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 : 10

Impatiens lobbiana Turcz., Bull. Soc. Imp. Naturalistes Moscou 32, 1: 270 (1859); Ruchisansakun et al., Blumea 63: 216 (2018).

– Type: Myanmar, Moulmein, 1846, Lobb 384 (lectotype KW [ KW001000647 ]; isolectotype K [ K000694801 ], designated by Ruchisansakun et al., 2018). Figure 5D–F .

Distribution. This species has been found on karst limestone in Vangvieng, Vientiane Province, central Laos. The original description was based on material collected in Myanmar ( Ruchisansakun et al., 2018).

Habitat and ecology. Impatiens lobbiana was found growing at the foot of a limestone hill near a stream in the mountains. It was growing in wet soil in primary evergreen valley forest at altitude c. 300 m.

Phenology. Flowering from June to August, fruiting from July to October.

Specimens examined. LAOs. Vientiane Province: Vangvieng District, base of limestone hill near stream, 26 vi 2012, Souvannakhoummane , K. & Phouthavong, K. KS 479 ( QBG, spirit collection at Pha Tad Ke Botanical Garden) ; Kasi District, Pha Ngern Mountain , 18°54′59.8′′N, 102°24′45.6′′E, 450 m attitude , 16 viii 2019, Lanorsavanh & Lamxay SL 1731 ( FOF, NHL) .

Impatiens lobbiana is very similar to I. spectabilis Triboun & Suksathan but differs in having the upper lateral petals obcordate (versus emarginate to obtuse) and dorsal petals obcordate (versus obovate). Our material differs from the type specimens by its larger, ovate lower petal that is broader than the upper petal, whereas the type has oblong to obovate lower petals that are narrower than the upper petals. However, more molecular studies are needed to reveal their true relationship.

Figures

Figure 5. A–C, Impatiens rubrostriata: A, plant with flowers; B, front view of flower; C, lateral view of flower. D–F, Impatiens lobbiana: D, plant with flower; E, front view of flower; F, lateral view of flower. G–I, Impatiens tigrina, red form: G, plant with flower; H, front view of flower; I, lateral view of flower. J, Impatiens tigrina, red-purple form, front view of flower. K and L, Impatiens tigrina, yellow form: K, front view of flower; L, lateral view of flower. Scale bars: 1 cm. Photographs: A–F, K. Souvannakhoummane; G–J, S. Lanorsavanh; K and L, K. Phoutthavong.