Journal of Threatened
Taxa | www.threatenedtaxa.org | 26 February 2026 | 18(2): 28419–28423
ISSN 0974-7907 (Online) | ISSN 0974-7893 (Print)
https://doi.org/10.11609/jott.9719.18.2.28419-28423
#9719 | Received 26 February 2025 | Final received 06 August 2025 |
Finally accepted 18 January 2026
Impatiens chamchumroonii
(Balsaminaceae), a new
record for the flora of Vietnam
Cuong Huu
Nguyen 1 , Diep Quang Dinh
2 , Dinh Duc Nguyen 3 & Keooudone Souvannakhoummane
4
1 Vietnam National University of
Forestry, Xuan Mai, Hanoi, 100000, Vietnam.
2 Nong Lam University - Hochiminh City, Linh Xuan, Hochiminh
City, 700000, Vietnam.
3 Faculty of Agriculture and
Forestry, Tay Nguyen University, Dak Lak, 630000,
Vietnam.
4 Faculty of Natural Science,
National University of Laos, Dongdok Campus, Xaythany District, Vientiane Capital, 01000, Laos.
1 nguyenhuucuong.tvr@gmail.com
(corresponding author), 2 dqdiep@gmail.com, 3 nddinh@ttn.edu.vn,
4 k.souvannakhoummane@nuol.edu.la
Editor: Inocencio
Buot Jr., University of the Philippines Los Banos, Laguna, Philippines. Date of publication: 26 February 2026 (online & print)
Citation:
Nguyen, C.H., D.Q. Dinh, D.D. Nguyen & K. Souvannakhoummane (2026). Impatiens chamchumroonii (Balsaminaceae),
a new record for the flora of Vietnam. Journal of Threatened Taxa 18(2): 28419–28423. https://doi.org/10.11609/jott.9719.18.2.28419-28423
Copyright: © Nguyen et al. 2026. Creative Commons Attribution 4.0 International License.
JoTT allows unrestricted use, reproduction, and
distribution of this article in any medium by providing adequate credit to the
author(s) and the source of publication.
Funding: None.
Competing interests: The authors declare no competing interests.
Acknowledgements: Authors would like to thank Mr. Tran Quoc An for his kind help during the fieldwork.
Abstract: The plant species Impatiens chamchumroonii of the Balsaminaceae
family was recorded for the first time in Vietnam. They are collected from Dak Lak province hill areas in 2023. The voucher specimens
of this species are housed in the herbarium of the Vietnam National University
of Forestry (VNF). The species is presented with a taxonomic description,
ecology, geographical distribution, occurrence in Vietnam, and field
photographs of new records.
Keywords: Dak
Lak Province, flowering plant, geographical distribution, new country
record, plant taxonomy.
The genus Impatiens L. (Balsaminaceae) comprises about over 1,000 species, ranking
as the 18th largest genus among flowering plants (Mabberley 2017; POWO 2025). Its distribution extends across
tropical and subtropical Africa and Asia, with the centre
of diversity and probable origin in southern China (Grey-Wilson 1980; Chen et
al. 2007). In Vietnam, the recognized diversity within the genus Impatiens
has expanded significantly over the past two decades, as evident from recent
studies reported with eight species I. purpureifolia
S.H.Huang & Y.M.Shui (Shui et al. 2011), I. kamtilongensis
Toppin (Vu et al. 2015), I. parvisepala S.X.Yu & Y.T.Hou (Hoang et
al. 2015), I. napoensis Y.L.Chen
(Nguyen et al. 2018), I. siculifera Hook.f. (Pham et al. 2019), I. monticola
Hook.f (Nguyen et al. 2021), I. lobulifera (Quan et al. 2024), and I. damrongii (Ha et al. 2025), which raised the number to
44 species in Vietnam (Tardieu 1944; Nguyen et al. 2000; Pham 2003). A field
survey in primary and secondary evergreen broad-leaved lowland forests of
central highland area in September 2023, the second and third authors collected
an unusual species of Impatiens. After careful morphological examination
of the species and analysis of available literature as well as collections of
different herbaria, namely, HN, LE, VNF, and VNM (all acronyms following Thiers
(2024), we identified this plant as Impatiens chamchumroonii
Suksathan & Ruchis.,
which was previously reported from Thailand (Suksathan
& Ruchisansakun 2022). This is the first record
of this species in the flora of Vietnam, the data for which are presented
below.
Material and Methods
All newly collected and studied
herbarium specimens are
presently stored in the herbarium of the Vietnam National University of
Forestry (VNF). Color photos of plants were taken in natural habitats.
Morphological observations and measurements were made on living plants, dried
specimens, and alcohol-preserved materials. Morphological characters were
described using the terminology proposed by Shui et
al. (2011) and Ruchisansakun et al. (2018).
Results
Impatiens chamchumroonii Suksathan
& Ruchis.; Impatiens Thailand 57 (2022). –
Type: R. Pooma. W.J.J.O. de Wilde, B.E.E. Duyfjes, V. Chamchumroon & K Phattarahirankanok 2506 (holo
BKF; iso L.). Thailand, Mukdahan
province, Dong Luang, Ban Nalak,
mixed deciduous forest slope, 160 m elevation, 24.viii.2001.
Description (Images 1 & 2): Lithophytic
annual herb, 20–70 cm tall. Stem erect, glabrous or finely pubescent, when
young: hypocotyl simple, elongate, 1–2 cm in diameter, epicotyl laxly branched,
sometimes slightly zigzag in upper parts. Leaves spirally arranged, more or
less congested at top of stem when young; petiole 1–3 cm long; lamina membranaceous, elliptic, 9–12 × 3.5–6.6 cm, apex acute,
base rounded to cuneate, often asymmetric, with a pair of ellipsoid glands at
or above the base, red to purple or with a white band along midrib adaxially,
pale green abaxially, finely pubescent on both surfaces, margin crenate-sernate. Lateral main veins 12–14 pairs. Inflorescences
axillary. Flowers solitary or in 2-flowered fascicles; bracts minute, linear.
Flowers white with pinkish purple lower petals, often distorted, 1.5–2 cm wide,
lower sepal and lateral united petals well-spaced and forming an elliptic
window on each side: pedicel 10–27 mm long. Finely pubescent. Lateral sepals 4:
outer pair yellowish white, obliquely oblong-obovate, 9.5–12.5 × 5–6 mm, apex
apiculate, upper margins connate almost to the tip, glabrescent: inner pair
minute, falcate, ca 1.5 mm long. Lower sepal bucciniform,
yellowish, inside with many orange red cross-stripes that are visible through
the open lateral windows, ca 9 × 7.5 mm, ca 5 mm deep, apex apiculate, abruptly
constricted then hooked and inflated into a ca 5 mm long, white bilobed spur,
each lobe scorpion tail-like with an acute, knob-like gland at apex. Dorial petal white, broadly elliptic to obovate, 7–11 x 5–7
mm, apex emarginate-mucronate, midvein with a low, indistinct crest in the
middle. Lateral united petals connate, clawed to 3.6 mm long upper petals white
(or slightly yellow) with yellow base, often subequal, broadly obovate to
suborbicular, 5–5.5 x 4.3–7.3 mm, apex rounded. Lower
petals white to purplish blue, base white with two red stripes, broadly ovate
to compressed obovate in outline, 13.5–17 × 12–18 mm, apex bilobed to 1/3–1/2
of its length, lobe apex emarginate, base with a white, low, triangular keel.
Stamen ca 5.3–5.5 mm long; anthers pale yellow. Ovary 4-carpellate, glabrous,
ca 3.3 mm long. Fruit oblong-clavate, ca 2 cm long.
Distribution: Thailand (Mukdahan),
Vietnam (Dak Lak province, Nam Ka commune).
Habitat: This species is found in
Thailand, at elevations of 160 m, in mixed deciduous forest slope. In Vietnam
it was observed in secondary evergreen broad-leaved forests, grows in areas
with many exposed rocks, next to paths with a canopy cover of 0.1–0.3, near the
forest along streams in association with Lagerstroemia calyculata,
Cratoxylon formosum,
Vitex pinnata, Colona thorelli, Canarium subulatum, Irvingia
malayana, Walsura robusta, Wrightia annamensis, Aporosa villosa, Ficus racemosa, Draceana
cambodiana at elevations of 400–450 m.
Specimens examined: Vietnam, Dak
Lak province, Nam Ka commune, grows in moist shady places near waterfalls,
along streams and occasionally on the rocky crevices covered by evergreen
broad-leaved forests, around point 12.298 0N, 108.040 0E,
at elevations of about 450 m, 12 September 2023, Dinh
Quang Diep, Nguyen Duc Dinh (VNF: NK35).
Note: Impatiens chamchumroonii
was first described in 2001, with its distribution initially reported as being
endemic to the Dong Luang counties in Mukdahan Thailand. Impatiens chamchumroonii
is somewhat similar to I. calcicola Craib in morphology of stem, leaves but differs in having
distorted flower (vs. never distorted in I. calcicola),
lower sepal and lateral united petals well-spaced and forming an elliptic
window on each side (vs. no window in I. calcicola)
and different spur shapes (slender with ellipsoid gland at apex in I. caleicola vs scorpion tail-like with an acute,
knob-like gland at apex in l. chamchumroonii).
Plants of I. chamchumroonii in Vietnam have
minor differences from the Thailand type specimens, including lower petals
white to purplish blue (vs. pinkish purple to purplish blue), flowers in
September–October (vs. July–August), and habitat in the mountainous area around
450 m elevation (vs. 145–160 m alt.).
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