Impatiens parishii Hook.f., Fl. Brit.

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 : 12-13

Impatiens parishii Hook.f., Fl. Brit. India 1: 456 (1875); Shimizu , S. E. Asian Stud. 8, 2: 209 (1970) ; Ruchisansakun et al., Blumea 63: 212 (2018).

– Type : Myanmar, Tenasserim near Moulmein, on limestone rocks, Parish s.n. (lectotype K [ K000694782 ], designated by Ruchisansakun et al., 2018). Figure 4G–I .

Distribution. This species has been discovered in Louangphabang Province, northern Laos. The original description was based on material from Myanmar, and it has also been reported from Thailand ( Ruchisansakun et al., 2018).

Habitat and ecology. Impatiens parishii was found growing on a limestone hill in humid mixed deciduous forest at an altitude of 500 m. In the dry season, only stems are present, and leaves develop in the rainy season. This species is very attractive and grows on limestone rock with Draceana sp. ( Asparagaceae ).

Phenology. Flowering from May to October, fruiting from September to November.

Specimens examined. LAOs. Louangphabang Province: Louangphabang District, Pha Nam Yat hill near Mekong river , 24 v 2011, K. Souvannakhoummane & K. Phoutthavong KS134 ( HNL, spirit collection at Pha Tad Ke Botanical Garden) ; ibid., 22 vi 2012, K. Souvannakhoummane & K. Phoutthavong KS481 ( HNL) ; Pak Ou District, 12 vii 2015, K. Phoutthavong & T. Song L–040 (living collection kept at Pha Tad Ke Botanical Garden) .

Impatiens parishii is very close to I. kerriae Craib but differs in having the pedicel shorter than the petioles (versus pedicel longer than petioles), lateral sepals pinkish to white, without spot (versus orange spot at midvein or nearby), and lateral united petals flat with yellow patch (versus grooved with orange-yellow to red patch). Impatiens parishii grows at low altitude near the Mekong river in Laos, whereas I. kerriae grows near the summits of limestone mountains in open areas.

Figures

Figure 4. A–C, Impatiens kerriae: A, plant with flower; B, front view of flower; C, lateral view of flower. D–F, Impatiens napoensis: D, plant with flower; E, front view of flower; F, lateral view of flower. G–I, Impatiens parishii: G, plant; H, front view of flower; I, lateral view of flower. Scale bars: 1 cm. Photographs: A–C, K and L, K. Phoutthavong; D–J, K. Souvannakhoummane.