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Taiwania 66(3): 360‒363, 2021
DOI: 10.6165/tai.2021.66.360
360
Dendrobium parahendersonii, a new orchid species (Orchidaceae) from
Southern Vietnam
Van Canh NGUYEN1, Leonid V. AVERYANOV2, Tatiana V. MAISAK2, Thi Lien Thuong NGUYEN1,
Van Khuong NGUYEN3, Ba Vuong TRUONG4,5,*
1. Institute of Applied Technology, Thu Dau Mot University, No. 6 Tran Van On Street, Phu Hoa Ward, Thu Dau Mot City, Binh
Duong Province, Vietnam. E-mail of VCN: nguyenvancanh@tdmu.edu.vn; TLTN: thuongntl@tdmu.edu.vn
2. Komarov Botanical Institute of the Russian Academy of Sciences, Prof. Popov Street 2, 197376, St. Petersburg, Russia. E-mail
of LVA: av_leonid@mail.ru; TVM:tmaisak@mail.ru
3. Tay Nguyen University, Le Duan, Buon Ma Thuot, Dak Lak Province, Vietnam. Email: nvkhuong@ttn.edu.vn
4. Graduate University of Science and Technology, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay
District, Ha Noi, Vietnam.
5. Institute of Tropical Biology, Vietnam Academy of Science and Technology, 85 Tran Quoc Toan, Dist.3, Ho Chi Minh City, Vietnam.
*Corresponding author’s E-mail: bavuong2019@yahoo.com
(Manuscript received 1 May 2021; Accepted 17 August 2021; Online published 20 August 2021)
ABSTRACT: Dendrobium parahendersonii discovered in southern Vietnam is described as new species to science. It belongs to
D. sect. Crumenata, and resembles D. hendersonii and D. exile in having a filiform, reed-like stem swollen at the base into a
quadrangular ellipsoid pseudobulb and flowering from the leafless part of stem but differs clearly in the details of its tepals and lip.
A morphological description, illustrations, data on habitat, phenology, and conservation status for the new species are provided.
KEY WORDS: Crumenata, Dendrobium hendersonii, new species, Orchidaceae, plant diversity, plant taxonomy.
INTRODUCTION
Dendrobium Swartz is one of the largest orchid
genera containing about 1450 known species widely
distributed in tropical and subtropical Asia from Sri
Lanka and India to Australia, New Guinea, and Pacific
islands (Pridgeon et al., 2014). In some recent
assessments (Pridgeon et al., 2014) D. section Crumenata
was included in Section Aporum Blume. In this paper, we
follow the concept of Wood (2015), which treats D. sect.
Crumenata as a separate section.
All representatives of the D. sect. Crumenata are
characterized byt the following: a fusiform,
pseudobulbous, swollen basal part of the stem consisting
of few internodes; leaves terete or dorsiventral,
conduplicate; many inflorescences spaced along the
leafless apical part of the stem, rarely on the leafy stem;
and each inflorescence bearing 1 or 2 flowers; usually
white flowers, with or without purple stripes and marks
on tepals, with a prominent mentum, and often with a
gland at the basal part of the column foot; the lip 3-lobed
or rarely entire, with an entire, undulate, erose, or dentate
median lobe and a disk usually with three hairy or
glabrous keels. The section comprises about 80 species
distributed from Myanmar, Thailand, China, Laos,
Cambodia, and Vietnam, to Malaysia, and Indonesia.
In Vietnam, Seidenfaden (1992) and Averyanov &
Averyanova (2003), list nine species forming two groups
for section Crumanata (= D. section Rhopalanthe Schltr.).
Species of the first group have terete leaves (D. exile, D.
pseudotenellum Guillaumin, D. dentatum Seidenfaden,
and D. lomatochilum Seidenfaden), and species of the
second group have dorsiventral, conduplicate leaves (D.
truncatum Lindl., D. hendersonii A.D.Hawkes &
A.H.Heller, D. podagraria Hook.f., D. crumenatum
Swartz, and D. annamense Rolfe.).
The new species of the section, which superficially
resembles D. hendersonii A.D.Hawkes & A.H.Heller and
D. exile Schltr., was found in Dong Nai Province of
southern Vietnam. The morphological description of the
new species, the information about its habitat,
conservation status, illustrations, and relevant taxonomic
notes are presented below.
MATERIAL AND METHODS
The measurements used for the description of D.
parahendersonii are based on the living plant collected
from Dong Nai province of southern Vietnam. Herbarium
material was initially preserved in 70% ethanol, then
dried and stored at VNM herbarium (Institute of Tropical
Biology, Ho Chi Minh City, Vietnam). Terminology for
the morphological description follows Beentje (2012).
TAXONOMIC TREATMENT
Dendrobium sect. Crumenata Pfitzer, 1888,
Pflanzenfamilien 2, 6: 174. – D. subgen. Crumenata
(Pfitzer) Kraenz., 1910, Pflanzenreich 45: 224.
2021 Nguyen et al.: Dendrobium parahendersonii, a new species from Vietnam China
361
Dendrobium parahendersonii Vuong, Aver. & Nguyen
V.C., sp. nov. Fig. 1
Type. VIETNAM, Dong Nai Province, Vinh Cuu
District, Ma Da Forest, evergreen lowland forest at
elevation about 200 m a.s.l., epiphyte on tree trunks above
3 meters from ground, 1 April 2021, Truong Ba Vuong,
Nguyen Van Canh, Nguyen Van Khuong, Nguyen Thi
Lien Thuong, BV 1142 (holotype – VNM 00069899!).
= D. hendersonii auct. non A.D. Hawkes & A.H. Heller, 1957: Seidenf.,
1992, Opera Botanica 114: 247; Tran Hop, 1998, Orch. Vietnam: 235;
Averyanov et al., 2015, Wulfenia 22: 153, fig. 5 F & G.
Diagnosis. The new species is morphologically
similar to D. hendersonii but clearly differs by
quadrangular pseudobulbs, quadrate or sub-quadrate in
cross section (vs. pseudobulbs distinctly flattened,
rhomboid in cross-section), smaller flower ca. 1 cm long
(vs. 2–2.5 cm long), shorter pedicel and ovary ca. 5 mm
long (vs. pedicel and ovary up to 1 cm long), smaller
median sepal ca. 5 mm long, 2 mm wide (vs. median sepal
10–15 mm long, 4–6 mm wide), median lip lobe half-
circular (vs. median lip lobe narrowly oblong), lip disc
with 5 distally fimbriate keels (vs. lip disc distally with
almost glabrous tripartite callus). Morphological details
of D. hendersonii used for the comparison are based on
data reported by Wood (2015).
Description. Epiphytic perennial herb. Stems densely
clustering, 30–80 cm long, filiform or reed-like, swollen
near the base; swollen part pseudobulbous, narrowly
ellipsoid, 2–4.7 cm long, 5 mm wide, consist of 1–3
internodes, quadrate of subquadrate in cross-section.
Leaves sessile, lanceolate, conduplicate, thick, 3.2–4.5
mm long, 3–5 mm wide, apical part somewhat narrowed,
apex shortly acuminate. Inflorescences many, on leafless
apical part of stems, 1–2-flowered; floral bract tubular,
acute, ca. 1 mm long. Pedicel and ovary ca. 5 mm long.
Flowers not widely opening, ca. 1 cm long from apex of
mentum to apex of median sepal, the sepals and petals
white, the lip white with purple nerves and orange disc.
Median sepal narrowly ovate, ca. 5 mm long, 2 mm wide,
with 5 veins, apex acute; lateral sepals oblique triangular,
ca. 4 mm long, 6 mm wide (at base), with 5 veins, apex
acute; mentum ca. 5 mm long, slightly forward curved,
apex obtuse. Petals oblong or narrowly obovate, ca. 4.5
mm long, 1.5 mm wide, with one vein, apex rounded to
obtuse. Lip narrowly obovate in outline, slightly recurved,
ca. 9 mm long, 4 mm wide, 3-lobed; side lobes oblique
ovate, ca. 4 mm long, 1.5 mm wide, rounded at apex, erect;
median lobe half-circular, ca. 2 mm long and wide,
margin finely undulate; disc with 5 bright orange, distally
fimbriate keels, 3 median keels extend from base to center
of median lobe, 2 lateral keels much shorter, coming from
base to median part of median lobe. Column stout, erect,
ca. 2 mm long, with 2 erect, triangular, acute stelidia;
column foot ca. 6 mm long, 2 mm wide, slightly forward
curved, grooved at base, below middle with small orange
callus; anther cap ovoid, ca. 1.2 mm tall, slightly retuse at
apex; pollinia 4, each half-ellipsoid, ca. 1.2 mm long
arranged in 2 groups; stigma obovate, concave; rostellum
in form of small transversal fold, not protruding. Fruits
not seen.
Etymology. The species name refers its closest
relation to D. hendersonii.
Habitat and phenology. Trunk and branch epiphyte in
broadleaved evergreen and semideciduous lowland and
submontane forests at elevation 200–800 m a.s.l. Flowers
all around the year, usually after light short weather cooling.
Distribution. Vietnam, provinces Dong Nai (Vinh
Cuu District), Khanh Hoa (Ninh Hoa District), and Lam
Dong. Endemic of the eastern part of Central Highlands
in southern Vietnam.
Proposed conservation status. The currently
available records suggest that the new species is locally
common. More field studies are needed for assessment of
its true conservation status. According to the IUCN
criteria (IUCN, 2019) it may be tentatively assessed at
present as “Data Deficient” (DD).
Other specimen examined. VIETNAM, southern Vietnam,
without exact location, Feb. 2004, sine coll., wild collected plant in culture,
herbarium and photos prepared in 9 Dec. 2020, L. Averyanov, T. Maisak,
AL 1279 (LE 01076988 http://en.herbariumle.ru/?t=occ&id=57020, LE
01088333 http://en.herbariumle.ru/?t=occ&id=46984). Khanh Hoa
Province, Ninh Hoa District, Ninh Phu Village, Mont Hon Heo (Suoi
Hoa Lan area), 18 July 2014, Le Hong Son et al., Tich 05-06-15, under
unpublished name – D. lehongsonii Tich (SGN, photos LE 01088650
http://en.herbariumle.ru/?t=occ&id=52117, drawing LE 01090981
http://en.herbariumle.ru/?t=occ&id=82430). Khanh Hoa Province,
broad-leaved evergreen forest at elevation 400–800 m a.s.l., epiphyte,
locally very common, 5 Nov. 2014, Nguyen Van Canh s.n. photo and
herbarium specimen prepared from cultivated plant in Nguyen Van Canh
private garden in 5 Dec. 2014 by L. Averyanov et al., CPC 7687 (LE
01088649 http://en.herbariumle.ru/?t=occ&id=52116, LE 01066324
http://en.herbariumle.ru/?t=occ&id=14677). Dong Nai Province, Cat Tien
National Park, 15 May 2020, Nguyen Van Canh, Truong Ba Vuong, BV
634 (LE 01073230 http://en.herbariumle.ru/?t=occ&id=15834). Dong
Nai Province, Vinh Cuu District, Ma Da Forest, evergreen lowland
forest at elevation about 200 m a.s.l., epiphyte on tree trunks above 3
meters from ground, 16 May 2020, Truong Ba Vuong, Nguyen Van
Canh, BV 1141 (VNM00032286).
Notes. Dendrobium parahendersonii is
morphologically very close to D. hendersonii and can be
easily misidentified in herbarium collections. Earlier the
new species was reported from Vietnam by Seidenfaden
(1992), Tran Hop (1998), and Averyanov et al. (2015)
under the name D. hendersonii. At the same time, it was
noted that Vietnamese plants originating from Lam Dong
Province differs somewhat from the type of D. hendersonii
in a series of morphological features indicated in Tixier’s
unpublished description reported by Seidenfaden (1992).
In 2014 Nguyen Thien Tich studied plants collected in
Khanh Hoa Province with the result that he proposed a new
species, D. lehongsonii Tich and illustrated his new taxon
with an excellent original illustration (LE 01090981
http://en.herbariumle.ru/?t=occ&id=82430) and numerous
photos (LE 01088650
http://en.herbariumle.ru/?t=occ&id=52117). Unfortunately,
his new species was left unpublished on his death in 2015.
Taiwania Vol. 66, No. 3
362
Fig. 1. Dendrobium parahendersonii Vuong, Aver. & V.C. Nguyen. A. Flowering shoots. B. Swelling basal parts of stems (pseudobulbs).
C. Cross section of the swelling part of stem. D. Leaves, adaxial and abaxial surface. E. Flowers, view from different sides. F. Median
sepal (fresh and alcohol preserved). G. Lateral sepals (fresh and alcohol preserved). H. Petals (fresh and alcohol preserved). I. Lip, view
from different sides. J. Column, pedicel, and ovary, side view. K. Column and column foot, view from different sides. L. Anther cap, view
from different sides. M. Pollinaria. Photos by Truong Ba Vuong from plant used for preparation of the holotype (Truong Ba Vuong et al.,
BV 1142). Photo correction and design by L. Averyanov and T. Maisak.
2021 Nguyen et al.: Dendrobium parahendersonii, a new species from Vietnam China
363
The study of additional collections from Dong Nai and
Khanh Hoa provinces confirms the distinction of
Vietnamese plants as a separate species, which is described
here with the name D. parahendersonii that refers to its
close relations to D. hendersonii.
The newly described species may be also compared
with D. exile Schltr. which has similar quadrangular
pseudobulbs. However, our plant differs in having
dorsiventral, lanceolate leaves (vs. leaves terete), smaller
flowers with sepals about 5 mm long (vs. sepals 10–12
mm long), and half-circular median lip lobe as long as the
side lobes (vs. median lip lobe narrowly ovate to elliptic,
distinctly longer than side lobes).
Currently, the new species is documented as
occurring in Dong Nai, Khanh Hoa, and Lam Dong
provinces. However, from personal observations, this
species is also fairly common in dry lowland primary
forests of Quang Nam and Gia Lai provinces (N.V. Canh
unpublished data).
Additional species examined. Dendrobium exile
Schltr.: VIETNAM, Lam Dong Province, Dalat Town area, fl. et coll.
in horto 16 Sep. 1985, L. Averyanov s.n. (LE 01077038
http://en.herbariumle.ru/?t=occ&id=82431). Lam Dong Province, Dalat
Town area, fl. et coll. in horto 16 Sep. 1985, L. Averyanov (LE
01066245 http://en.herbariumle.ru/?t=occ&id=13708); Dong Nai
Province, 7 Jan. 1990, Vu Ngoc Long, B 075 (LE 01066254
http://en.herbariumle.ru/?t=occ&id=13717); Lam Dong Province, Dalat
Town area, fl. et coll. in horto 7 July 1987, L. Averyanov s.n. (LE
01066245 http://en.herbariumle.ru/?t=occ&id=13708). Daklak, Krong
No District, Nam Ha municipality, Day Sap – Gia Long Waterfall
Historical, 27 Nov. 2014, Averyanov et al., CPC 7679 (LE 01066249
http://en.herbariumle.ru/?t=occ&id=13712); VIETNAM, Kon Tum
Province, fl. et coll. In horto 17 December 2015, Averyanov et al., AL
209 (LE 01077039 http://en.herbariumle.ru/?t=occ&id=82432).
Dendrobium hendersonii A.D. Hawkes & A.H.
Heller: THAILAND, Betong, Pattani, on tree by stream in evergreen
forest, 28 August 1923, A.F.G., Kerr 0102 (K000596869, K000596870,
type of D. herdersonii)
https://apps.kew.org/herbcat/detailsQuery.do?imageId=288180&page
Code=1&presentPage=1&queryId=1&sessionId=F6143BDDE272EE
AC4C5E454E04AC13CB&barcode=K000596871
ACKNOWLEDGMENTS
The author would like to thank to the reviewers for their
kindness suggestions. The studies, results of which are
presented in this paper were supported in parts by Institute of
Applied Technology from Thu Dau Mot University with fund
number: NNC. 21.2-001, by the Institute of Tropical Biology of
Vietnam Academy of Science and Technology (Ho Chi Minh
City), Russian Found of Basic Researches (RFBR) “Inventory,
taxonomy and geography of the orchids (Orchidaceae) of
Vietnam”, 20-04-00339, “The assessment of orchids
(Orchidaceae) in Vietnam and their conservation status”, Viet_a
21-54-54001, and was carried out in the framework of the
institutional research project of the Komarov Botanical Institute
of the Russian Academy of Sciences “The Vascular Plants of
Eurasia: the systematics, flora and plant resources” (АААА-
А19-119031290052-1).
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