Impatiens tigrina Suksathan & Triboun, Gard. Bull.

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 : 13-14

Impatiens tigrina Suksathan & Triboun, Gard. Bull. Singapore 61, 1: 177 (2009).

– Type: Thailand, Udon Thani Province, Ban Phue District , shaded sandstone table, c. 300 m altitude, 8 vii 2008, P. Suksathan, M. Wongnak, H. Boonnuang & K. Keeratikiat 4567 (holotype QBG; isotypes BK, SING). Figure 5G–I (red form), J (red-purple form), K,L (yellow form) .

Distribution. This species has been found in Phou Khao Khouay National Protected Area, Vientiane Capital and Bolikhamxai Province, Laos. The original description was based on material from Udon Thani Province, Thailand ( Suksathan & Triboun, 2009).

Habitat and ecology. Growing in humid, sandy soil in shade by bamboo forest and in wet table-rock areas at c. 300 m altitude.

Phenology. Flowering from June to September, fruiting from August to November.

Specimens examined. LAOs. Vientiane Province: Xaythani District, Ban Na Khaiy, near Wat Pha Bat Eow Khan, 27 ix 2012, Souvannakhoummane & Xayachak KS419 (HNL, QBG, spirit collection at Pha Tad Ke Botanical Garden); ibid., 19 vii 2013, Phoutthavong & Souvannakhoummane KP413 ( HNL, spirit collection at Pha Tad Ke Botanical Garden) ; Bolikhamxai Province, Thaphabath District , 22 vii 2019, Lanorsavanh, Souvannkhoummane & Xaiyavong SL1734 ( FOF, HNL) .

Impatiens tigrina was originally described from Thailand by Suksathan and Triboun (2009) as resembling I. charanii T.Shimizu , but it differs in its outer lateral sepals not connected (versus the outer lateral sepals connected), and the simple spur (versus bifid). Around the foothills of Phou Khao Khouay in Laos, this species has three variants with yellow, red and red-purple flowers. A different colour form, pinkish red, was later observed in Thailand (Piyakaset Suksathan, Queen Sirikit Botanical Garden , Chiang Mai, personal communication).

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.