Corresponding author: Young-Dong Kim ( email@example.com )
Academic editor: Pavel Stoev
© 2017 Seong-Hyun Cho, Bo-Yun Kim, Han-Sol Park, Chhang Phourin, Young-Dong Kim.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation: Cho S-H, Kim B-Y, Park H-S, Phourin C, Kim Y-D (2017) Impatiens bokorensis (Balsaminaceae), a new species from Cambodia. PhytoKeys 77: 33-39. https://doi.org/10.3897/phytokeys.77.11345
Impatiens bokorensis, a new species of family Balsaminaceae from Phnum Bokor National Park in southwestern Cambodia, is described and illustrated. The species is similar to I. patula, but is readily distinguished by the orbicular-obovate dorsal petal, shorter pedicels and larger seeds.
Phnum Bokor National Park, Endemic species, Impatiens, Cambodia
Balsaminaceae is a family consisting of about 1,000 species mainly distributed in tropical Africa, Madagascar, southern India and Sri Lanka, the eastern Himalayas and southeastern Asia and is absent from Australia and South America (
Impatiens is classified into two subgenera (subgenus Impatiens Warb. and subgenus Acaulimpatiens Warb.) based on the presence or absence of cauline leaves. These two subgenera comprise 14 sections (subgenus Acaulimpatiens, two sections and subgenus Impatiens, 12 sections) mainly segregated by phyllotaxy, inflorescence and spur characters (Warburg and Reiche 1895,
In Indochina, there are around 120 species of Impatiens and the present count includes approximately 40 species from Vietnam (
Except for I. balsamina and I. cardiophylla, most species in Cambodia have been considered endemic species, with I. relaxata, I. vagans and I. zygosepala restricted to a local area with only a very small number of specimens. There is a need to re-evaluate and resurvey areas of the previous collection of specimens through a detailed taxonomic study of each species.
During the recent floristic survey, one species of Impatiens was collected at Bokor National Park in Southwestern Cambodia that does not appear to be similar to previously reported species (Figures
Impatiens bokorensis A Flowering individual B Fruiting individual C–D Developing flower bud E Mature flower (before pollination) F–G Mature flower (after pollination) H Developing gynoecium I Petals J Androecium K Developing fruit L–M Seed N–O strigose-ciliate at leaf base: Cho et al.
CAMBODIA. Kampot Province, Phnum Bokor National Park, sandstone tables in evergreen forest margin, 10°38'20.8"N, 104°00'16.0"E, a.s.l. 1,050 m, 24 August 2015, with flowers, Cho S.H, Kim B.Y., Park H.S., Chhang Phourin
Impatiens bokorensis is most similar to the Thailand endemic species I. patula Craib in habit but is readily distinguished from the latter by the orbicular-obovate dorsal petal, shorter pedicels and larger seeds (Table
Comparison of key features of Impatiens bokorensis and I. patula.
|Taxonomic traits||Impatiens bokorensis||I. patula|
|upper surface||pubescent||pubescent with scurfy hairs|
|lower surface||glabrous to sparsely pubescent||pubescent on nerves only or tomentose all over|
|strigose-ciliate at base||1–2.7 mm||1–1.4 mm|
|Pedicel||1.4–2.0 cm||2.3–3(–5) cm|
|Dorsal petal||orbicular-obovate, ca. 6 × 8 mm, horned at apex, horn 2.2–2.3 mm long||cordate, 7 mm long, horned at apex, horn 3 mm long|
|Seeds||3.8–4.6 × 2.6–3.2 mm||3.5 × 2.5 mm|
Herbs, annual, terrestrial, hermaphroditic. Stems erect, 15–40 cm tall, tinged purplish red, branched, glabrous or sparsely puberulous on the upper part. Leaves simple, alternate; petioles subsessile to 1.4 mm; leaf blade lanceolate to ovate-lanceolate, apex acuminate, base narrowly cuneate to attenuate, 2.5–7.0 × 0.6–2.0 cm, upper surface pubescent, lower surface glabrous to sparsely pubescent, secondary veins pinnate, 6 to 8 on each side of mid-vein, margin serrate, teeth mucronate and purple tinged, strigose-ciliate at base; strigose-ciliate, 4–14, 1–2.7 mm long, purple to purplish black, minutely puberulous at base. Flowers axillary, solitary, rarely 2 fascicled, zygomorphic, minutely puberulous; pedicels slender, erect, purplish red, 1.4–2.0 cm long, glabrous, bracteate at base; bracts linear, up to 4 mm; lateral sepals 2, linear-lanceolate, 2.5–3 mm long, glabrous; lower sepal funnel-form, pink, ca. 5 mm long, ca. 3 mm deep; spur 17–23 mm long, slightly curved; dorsal petal, orbicular-obovate, ca. 6 × 8 mm, horned at apex, horn 2.2–2.3 mm long; lateral united petals separate, bilobed, ca. 11 mm long; upper petals oblong, 6.0–6.5 × ca. 3.0 mm, minutely apiculate; lower petals, 9.0–9.3 × 3.5–3.8 mm; androecium ca. 2.8 × 1.6 mm; stamens 5, connate, surrounding gynoecium; filaments ca. 0.7 mm; ovary fusiform, pubescent, ca. 2.5 × 1.0 mm; style glabrous, ca. 0.2 mm long; stigma 5, ca. 0.25 mm long. Fruit a capsule, fusiform, ca. 15 × 6 mm, pubescent with scurfy hairs, 3-seeded. Seeds obovoid, slightly compressed, 3.8–4.6 × 2.6–3.2 mm, pubescent with spirally sculptured hairs.
CAMBODIA. 16 November 2015, with fruits, Cho et al.
Flowering specimens were collected in August and fruiting specimens in November.
Impatiens bokorensis grows on sandstone tables in evergreen forest margins at 1,050 m a.s.l.. Endemic to southwestern Cambodia, I. bokorensis is at present known only in the type locality.
Cho et al.
Impatiens bokorensis was collected in Phnum Bokor National Park in southwestern Cambodia. Until now, only one population, consisting of ca. 200 individuals, has been discovered in the park area; therefore, it is preliminarily classified as data deficient (DD) according to the IUCN Red List criteria (IUCN 2001).
We thank Ms. Hye-Woo Shin (http://www.hyewoo.com/) for preparing the line drawing. This work was supported by a grant from the National Institute of Biological Resources (NIBR), funded by the Ministry of Environment (MOE) of the Republic of Korea (NIBR201604201). Also, We would like to thanks Dr. Rajeev Singh and Dr. Mike Skinner for their valuable comments and suggestions.