New Orchids in the Flora of Vietnam Ⅲ (Collabieae, Malaxideae, Nervilieae and Orchideae)

Abstract

The paper presents new data on the orchid diversity in Vietnam obtained in 2016-2020. It contains descriptions of one genus (Apetalanthe) and two species new to science (Apetalanthe gracilis, Nervilia appressifolia), as well as one genus (Neottianthe) and four species (Calanthe tricarinata, Collabium yunnanense, Dendrobium praecinctum, Neottianthe secundiflora) new for the flora of Vietnam. Apetalanthe is particularly remarkable for the reduction of petals. The accepted name, synonyms, type, citations of relevant regional taxonomic publications, data on ecology, phenology and distribution, estimated IUCN Red List status, studied specimens, brief taxonomic notes, and illustrations are provided for each recorded species.

Full text

Taiwania 65(4): 478‒492, 2020
DOI: 10.6165/tai.2020.65.478
478
New Orchids in the Flora of Vietnam Ⅲ (Collabieae, Malaxideae,
Nervilieae and Orchideae)
Leonid V. AVERYANOV1,*, Ba Vuong TRUONG2,3, Van Canh NGUYEN4, Tatiana V. MAISAK1,
Quang Diep DINH4, Maxim S. NURALIEV5,6, Khang Sinh NGUYEN7, Van Tan CHU8
1. Komarov Botanical Institute of the Russian Academy of Sciences, Prof. Popov Street 2, 197376, St. Petersburg, Russia.
2. Institute of Tropical Biology, Department of Biological Resources, Vietnam Academy of Science and Technology, Tran Quoc
Toan Street 85, District 3, Ho Chi Minh City, Vietnam. E-3.
3. Graduate University of Science and Technology, Vietnam Academy of Science and Technology, Hoang Quoc Viet Road 18, Nghia
Do, Cau Giay District, Hanoi, Vietnam. E-mail: bavuong2019@yahoo.com
4. Institute of Applied Technology, Thu Dau Mot University, Tran Van On Street 6, Phu Hoa Ward, Thu Dau Mot City, Binh Duong
Province, Vietnam. E-mail:VCN: nguyenvancanh@tdmu.edu.vn; QDD: dinhquangdiep@tdmu.edu.vn
5. Joint Russian-Vietnamese Tropical Scientific and Technological Center, Cau Giay, Hanoi, Vietnam.
6. Department of Higher Plants, Biological Faculty, M.V. Lomonosov Moscow State University, Leninskie Gory 1, 12, 119234,
Moscow, Russia. E-mail: max.nuraliev@gmail.com
7. Institute of Ecology and Biological Resources, Vietnam Academy of Science and Technology, Hoang Quoc Viet Road 18, Nghia
Do, Cau Giay, Hanoi, Vietnam. E-mail: khangnguyensinh@yahoo.com
8. The Center for Rescue and Conservation of Organism, Sa Pa District, Lao Cai Province, Vietnam.
Corresponding author’s email: av_leonid@mail.ru or av_leonid@yahoo.com
(Manuscript received 27 August 2020; Accepted 28 September 2020; Online published 6 October 2020)
ABSTRACT: The paper presents new data on the orchid diversity in Vietnam obtained in 2016–2020. It contains descriptions of
one genus (Apetalanthe) and two species new to science (Apetalanthe gracilis, Nervilia appressifolia), as well as one genus
(Neottianthe) and four species (Calanthe tricarinata, Collabium yunnanense, Dendrobium praecinctum, Neottianthe secundiflora)
new for the flora of Vietnam. Apetalanthe is particularly remarkable for the reduction of petals. The accepted name, synonyms, type,
citations of relevant regional taxonomic publications, data on ecology, phenology and distribution, estimated IUCN Red List status,
studied specimens, brief taxonomic notes, and illustrations are provided for each recorded species.
KEY WORDS: Indochina, nature protection, new genus, new species, new records, orchids, plant geography, plant taxonomy.
INTRODUCTION
This paper continues the successive publication of
new data on the orchid diversity in Vietnam (Averyanov
et al., 2018a–g, 2019a–f; Gruss et al., 2019, 2020; Nguyen
et al., 2020a, b) obtained in 2016–2020. Similar to the
previous papers, it summarizes the results of joint efforts
of professional botanists and orchid enthusiasts on studies
of the Vietnamese native orchids. We report here one
genus, Apetalanthe and two species new to science,
Apetalanthe gracilis (Orchideae, Orchidinae), Nervilia
appressifolia (Nervilieae, Nerviliinae), as well as one
genus, Neottianthe and four species, Calanthe tricarinata,
Collabium yunnanense (Collabieae), Dendrobium
praecinctum (Malaxideae, Dendrobiinae) and Neottianthe
secundiflora (Orchideae, Orchidinae) new for the flora of
Vietnam. In the suprageneric classification we followed
the most recent taxonomic treatment of the orchid family
proposed by M.W. Chase et al. (2015). The accepted plant
name, synonyms, type, citations of relevant regional
taxonomic publications, data on ecology, phenology and
distribution, estimated IUCN Red List status, studied
specimens, brief taxonomic notes, and illustrations are
provided for each recorded species.
MATERIALS AND METHODS
Voucher specimens and photo materials cited here
were obtained during the years 2016–2020. Collected
plants, inflorescences and flowers were herbarized
directly or fixed and stored in 60–65% ethanol prior to
preparation of herbarium specimens. In the descriptions
of quantitative characters, infrequent extreme values (i.e.
rarely occurring minimal and maximal values) of a
variation range are parenthesized before and after the
normal variation range. Detailed analytical photos of
plant parts were made from the living or liquid-preserved
plants prior to preparation of the voucher herbarium
specimens. In the citation of the taxa distribution in
Vietnam, including the provinces, we follow the modern
official administrative division of the country (Vietnam
Administrative Atlas, 2015; Provinces of Vietnam,
2019). The online version of the IUCN Red List of
Threatened Species (2016) was used for tentative
estimation of species conservation status. Place of the
housing of cited specimens is indicated by
internationally accepted herbarium acronyms (Thiers,
2020). The studied specimens are available in the
database of the LE Herbarium (http://en.herbariumle.ru).

2020 Averyanove et al. : New Orchids in the Flora of Vietnam
479
Fig. 1. New orchids in the flora of Vietnam. Apetalanthe gracilis Aver. & Vuong. Living plant and details of fresh flowers. Photos by
Nguyen Thanh Luan, design by L. Averyanov and T. Maisak (made from living plants used for preparation of the type specimen AL 1238).
The studied taxa are listed below in alphabetical order.
TAXONOMIC TREATMENT
List of new orchids in the flora of Vietnam
Apetalanthe Aver. & Vuong, gen. nov. (Orchideae:
Orchidinae)
Type: A. gracilis Aver. & Vuong
Diagnosis. The new genus differs from the most
morphologically close genera Orchis L. and Ponerorchis
Rchb.f. in the emarginate median sepal, visual absence of
petals (completely reduced or fused with median sepal),
naked viscidia without bursicle and large swelling
rostellum hanging above stigma. Monotypic genus.
Etymology. The name of the genus refers to its
apetalous flowers.
A. gracilis Aver. & Vuong, sp. nov.
Fig. 1–3
Described from NW Vietnam. Type: VIETNAM, Lao
Cai Province, Fansipan Mountain, 23 June 2019, Truong
Ba Vuong, Nguyen Thanh Luan, AL 1238 (holotype - LE
LE01076866, http://en.herbariumle.ru/?t=occ&id=18974;
photo of living plant prior to preparation of holotype, LE
LE01061298, http://en.herbariumle.ru/?t=occ&id=12492;
drawing of the type specimen, LE LE01087235,
http://en.herbariumle.ru/?t=occ&id=18950).

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Fig. 2. New orchids in the flora of Vietnam. Apetalanthe gracilis Aver. & Vuong. Morphological details. A. Flattened flower with lip removed,
median sepal in side view. B. Flattened flower with lip removed, median sepal in front view. C. Flattened flower with lip removed, median
sepal flattened and sagittally dissected at the cucullate apex. D. Flattened flower with lip removed, view from behind. E. Lips of flowers of
different individuals. F. Column and median sepal, front view. G. Column with pollinaria removed, front view. H. Portion of stem. I. Apical
half of ovary. J. Papillae typical of margins of leaves, sepals, petals, as well as on ridges of stem and ovary. Photos and design by L.
Averyanov and T. Maisak (made from alcohol-preserved material used for the preparation of the type specimen AL 1238).
Description. Herb terrestrial or lithophytic,
tuberiferous, stoloniferous, generally glabrous. Tuber
underground, subglobular, ovoid or shortly cylindrical,
pale yellowish to light brownish, (4)4.5–7(8) mm long,
densely covered with root hairs; tuber of the next
generation developing at the apex of underground terete
whitish stolon (4)5–10(or more?) mm long and 1–1.2
mm in diameter. Roots (0)1–2, at base of stem, short and
fleshy, hairy. Stem arising from tuber, ascending,
oblique or erect, (3.5)4–8(9) cm tall, (0.8–)1(–1.2) mm
in diameter, white at base, grassy green in distal half,
with fine longitudinal papillulose ribs, at base bearing 3–
4 tubular white or light greenish bracts 3–12 mm long
and 1.4–1.8 mm wide (when flattened) with obtuse or
acute apex, at middle with 1 suberect or horizontally
recurved cauline leaf. Leaf sessile, narrowly lanceolate,
often slightly falcate, conduplicate, uniformly grassy
green, (2)2.5–3(3.5) cm long, (2.5)3–4(4.5) mm wide,
tapering from wide base to obtuse apex, finely
papillulose along margin, abaxially with prominent
median vein. Inflorescence a terminal lax somewhat
secund spike with (1)2–3 flowers; peduncle ebracteate,

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grassy green, (1.8)2–2.2(2.4) cm long; rachis grassy
green, (0.8)1–1.8(2) cm long. Floral bracts leaf-like,
narrowly to broadly lanceolate, horizontally recurved,
grassy green, (8)12–15(17) mm long, (2.5)3–4(4.2) mm
wide, tapering from broad base to acute apex, papillulose
along margin. Flowers distant with 6–8 mm between
them on rachis, sessile, resupinate, widely opening,
white with lip bearing 7 longitudinal purple stripes along
veins and at spur base, (7.5–)8(–8.5) mm across. Median
sepal erect, 3-veined, broadly ovoid, cymbiform, (2.8)3–
3.2(3.3) mm long, (3.7)3.8–4(4.1) mm wide (when
flattened), obscurely 4-dentate and cucullate at apex,
sparsely papillulate abaxially and along margin,
embracing column. Lateral sepals reflexed or recurved,
1-veined, obliquely narrowly obovate, (3.9)4–4.2(4.3)
mm long, (1.9–)2(–2.1) mm wide, blunt to rounded at
apex, papillulate along margin. Petals absent during
flowering. Lip horizontal to downwards directed, 7-
veined, spurred, broadly obovate, almost flat, (5.8)6–
6.5(6.7) mm long, (5.7)5.8–6.2(6.3) mm wide, with 2
small ovoid papillulose transversal calli at entrance of
spur, 3-lobed at apex; lobes broadly triangular, 1–1.2
mm long, 2–2.2 mm wide, finely denticulate or
irregularly serrulate along margin; spur at right angle to
lip, horizontal or upward directed, narrowly cylindrical-
conical, straight to slightly curved upwards, obtuse, as
long as ovary, (6.3)6.5–7(7.2) mm long, (1.4)1.5–1.8(1.9)
mm broad at base, papillulose inside. Column erect, stout,
(1.9)2–2.2(2.3) mm tall, 1–1.2 mm wide; anther erect, 1–
1.2 mm tall, with 2 broad parallel, adjacent thecae
narrowing at base into short tubes embracing caudicles;
viscidia 2, exposed (lacking separate or common
bursicle), each viscidium between narrowly acute erect
teeth of large swelling hemispheric lateral rostellum
lobes; auricles broadly conoid, finely verruculose;
stigma entire, rectangular lunate, slightly concave to
almost flat, as wide as rostellum, placed below rostellum,
facing to broad, almost circular spur entrance.
Pollinarium clavate, consisting of sectile pollinium with
numerous massulae, short fleshy terete caudicle and
ovate to almost circular viscidium at base. Ovary straight
to recurved, grassy green, terete to fusiform, (5.5)6–8(10)
mm long, (1.4)1.5–1.8(2) mm in diameter, with
longitudinal papillulose ribs. Fruit a fusiform capsule.
Etymology. The species name refers to the slender
and elegant plant appearance.
Habitat, phenology and conservation status.
Terrestrial and lithophytic tuberiferous herb. Wet mossy
open places on rocky outcrops in humid evergreen
broad-leaved forest between 2000 and 3000 m a.s.l. Very
rare. Flowers in June–July, fruits in August–September.
Estimated IUCN Red List conservation status: DD.
Distribution. NW Vietnam (Lao Cai Province,
Hoang Lien Son Range, Fansipan peak area). Endemic
to NW Vietnam. Only known from the one location.
Notes. The new genus is apparently close to Orchis
L. and Ponerorchis Rchb.f. ( = Chusua Nevski) in plant
habit and general floral morphology. Superficially, it
particularly resembles some forms of the rare Himalayan
taxon, Orchis chusua var. nana King & Pantl. (=
Ponerorchis nana (King & Pantl.) Soó). However, our
plant differs from all representatives of Orchis and
Ponerorchis in emarginate median sepal (vs. median
sepal round, obtuse or acute, but never emarginate),
absence of petals (vs. petals well developed, as long as
sepals and entirely free from them), presence of 2 small
ovoid transversal calli at entrance of spur (vs. lip lacking
swellings at entrance of spur), viscidia exposed and
lacking a bursicle (vs. viscidia covered by 2 separate
bursicles or 1 common bursicle), and large fleshy
hemispheric rostellum as large as stigma, situated above
stigma at the base of the anther and bearing at apex 4
narrowly pyramidal acute erect teeth (vs. rostellum
mostly represented by its median lobe forming more or
less prominent fold placed between the bases of thecae
and forming distally 2 rostellar arms). The mentioned
combination of morphological characters is unique and
was not observed in any members of other related Asian
Orchis-associated genera, like Amitostigma Schltr.,
Hemipilia Lindl., Hemipiliopsis Y.B.Luo & S.C.Chen,
Neottianthe Schltr., and Tsaiorchis Tang & F.T.Wang.
Such characters as emarginate median sepal, visual
absence of petals and swelling globular rostellum are
apomorphies observed only in the discovered plant.
It is noteworthy that an orchid with similar
modification of perianth is currently accepted (Chase et
al., 2015) as the monotypic genus Steveniella Schltr.
(comprising the species S. satyrioides (Spreng.) Schltr.,
distributed in Iran, Turkey, the Caucasus and the
Crimea). The reduction in the number of perianth
segments in Steveniella is caused by the fusion of all
three sepals into a synsepalum with the formation of a
broad hood, whereas in Apetalanthe the petals are
apparently absent (or fused with median sepal).
A possible interpretation of the perianth of
Apetalanthe is the complete union of the petals with the
median sepal. The presence of three vascular traces in
the median sepal of Apetalanthe makes this organ similar
to the lip of many Orchidaceae (Rudall, Bateman, 2002;
Rudall et al., 2013). As it has been argued by Rudall et
al. (2013) with respect to the three-traced lip, the
hypothesis of the compound lip nature (implying a union
of the median petal with two outer staminodes) can
hardly be endorsed or refuted at the current state of
knowledge. In the same way, the idea of the union of the
petals with the median sepal in Apetalanthe rather than
their complete reduction cannot be discarded.
The ecology and distribution of Apetalanthe in
Vietnam are probably very similar with those of another
regional endemic from the same subtribe, the monotypic
genus Tsaiorchis Tang & F.T. Wang.
Apetalanthe gracilis is a rare highland orchid currently

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Fig. 3. New orchids in the flora of Vietnam. Apetalanthe gracilis Aver. & Vuong. A, B. Flowering plants. C. Basal portion of stem, tuber,
roots and stolon with young tuber of the next generation. D. Leaf, adaxial side. E. Portion of stem from its middle part. F. Inflorescence. G.
Flower, front view. H. Sepals, front view. I. Flattened median sepal dissected in apical cucullate part. J. Flattened lip, abaxial side. K.
Column, front view. L. Column, half-side view. M. Pollinaria. N. Structure of micro-papillae observed along margins of leaves, sepals and
petals, as well as on ridges of stem and ovary. All drawn from the type AL 1238 by L. Averyanov and T. Maisak.

2020 Averyanove et al. : New Orchids in the Flora of Vietnam
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Fig. 4. New orchids in the flora of Vietnam. Calanthe tricarinata Lindl. A. Inflorescence prior to preparation of a voucher herbarium
specimen. B. Inflorescence in the natural habitat. C. Leaves. D–F. Flowers in different views. G. Ripening fruit. H. Old dehisced capsule.
Photos by Nguyen Thanh Luan from the specimen Truong Ba Vuong, Nguyen Thanh Luan, AL 1234, design by L. Averyanov and T. Maisak.
known only from the area of Fansipan peak.
Consequently, its conservation status may be assessed as
“Data Deficient” (DD) following the IUCN Red List
terms and criteria. Meanwhile, it is probable that this
species inhabits some other high peaks of Hoang Lien
Son Range including its NW extension in SE Yunnan
(China). The discovered plant represents the ninth genus
of Orchidaceae endemic (and subendemic) to Vietnam
along with Ascocentropsis Senghas & Schildh.,
Bidoupia Aver., Ormerod & Duy, Cleisostomopsis
Seidenf., Eparmatostigma Garay, Hayata Aver., Lockia
Aver., Vietorchis Aver. & Averyanova and Zeuxinella
Aver. Similar to all these genera, the newly discovered
plant deserves special attention for its conservation as a
local endemic of a high taxonomical rank having very
limited distribution.
Calanthe tricarinata Lindl. 1833, Gen. Sp. Orchid. Pl.:
252; Su Horng-Jye, 2000, Fl. Taiwan 5: 790, photo 94;
Pearce, Cribb, 2002, Orchids of Bhutan: 291, fig. 65, pl.
11; Chen et al., 2009, Flora of China 25: 297, fig. 426;
Clayton, Cribb, 2013, Genus Calanthe: 148, fig. 47, pl.
21A, B; Rokaya et al., 2013, Nord. J. Bot. 31: 519; Lin
et al., 2016, Taiwania 61, 2: 86; Zhou et al., 2016,
Phytotaxa 276: 25.
Fig. 4
Described from Nepal (“Lindl. in Wall. Cat. no 7339
in Hab. in Napalia”). Type – “7339 Calanthe tricarinata
Lindl. Napalia 1821 Calanthe ecalcarata, Wall.
Monthes vallii Napalia Julio 1821 fl.” (K – K001127196
http://specimens.kew.org/herbarium/K001127196).
Habitat, phenology and conservation status (in
Vietnam). Terrestrial herb. Primary humid evergreen

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broad-leaved montane forest on granite at elevations of
2000–2500 m a.s.l. Flowers in June–July. Rare.
Estimated IUCN Red List status: DD.
Distribution. NW Vietnam (Lao Cai Province,
Fansipan Mountain). Bhutan, Nepal, NE India, Pakistan,
N Myanmar, Thailand, mainland China, Korea, Taiwan,
Japan.
Notes. This species is a typical element of the
subtropical and warm temperate flora of mainland Asia.
Its discovery in Vietnam extends its known distribution
area to the highland regions of northern Indochina
situated within the tropical latitudes. Studied plants from
Vietnam slightly differ from the typical C. tricarinata by
the very small keel or plate on the lip disc and can
represent a separate variety.
Studied specimen. NW Vietnam, Lao Cai Province, Fansipan
Mountain, 22 June 2019, Truong Ba Vuong, Nguyen Thanh Luan, AL
1234 (LE LE01066670 http://en.herbariumle.ru/?t=occ&id=12428).
Collabium yunnanense Ormerod, 2013, Taiwania 58(1):
22, fig. 2.
Fig. 5
Described from southern China, Yunnan (“Lushui
Xian, Luobenzhuo Xiang, E’ga Cun, on forest road at km
30, E side of Gaoligongshan, 2200 m”). Type – “9 Aug
2005, Gaoligong Shan Biodiversity Survey, H. Li et al.,
25814” (holotype – CAS).
Habitat, phenology and conservation status (in
Vietnam). Terrestrial and lithophytic creeping herb.
Primary evergreen broad-leaved montane forests,
swampy and cloudy highland thickets on granite and
sandstone at elevations of 1700–1900 m a.s.l. Flowers in
May–June. Not common. Estimated IUCN Red List
status: DD.
Distribution. NW Vietnam: provinces Lao Cai (Bat
Xat District, Bat Xat Nature Reserve) and Son La (Moc
Chau District, Pha Luong Mountain). S China (Yunnan
Province).
Notes. This species, which was described after the
publication of the “Flora of China” (Chen et al., 2009),
is readily distinguishable from the closely related
Collabium chapaense (Gagnep.) Seidenf. & Ormerod
and C. formosanum Hayata by a short column and the
lower lip portion with two thick fleshy keels interposed
apically by a short transverse keel-like callus (Ormerod,
2013). In China, C. yunnanense was reported as an
epiphytic plant growing in subtropical forest on granite
at an elevation of 2200 m a.s.l. This unattractive, rarely
flowering plant probably has a wide distribution in
highland areas of NW Vietnam, but is not yet well
documented by herbarium collections.
The protologue of C. yunnanense (Ormerod, 2013) is
illustrated only with a drawing. Here, we publish the
analytical photos of this species for the first time.
Studied specimens. NW Vietnam, Son La Province, Moc
Chau District, Chieng Son Commune, Pha Luong Village, primary
cloud evergreen broad-leaved forest on flat Pha Luong Mountain
summit composed with eroded red-brown sandstone at an elevation of
1750–1850 m a.s.l. around point 20°40’23.0N 104°37’52.0E, creeping
terrestrial and lithophytic herb on shady mossy boulders, not common,
23 September 2016, L.Averyanov, N.T.Hiep, N.S.Khang, C.Q.Ngan,
T.V.Maisak, N.T.Son, CPC 8001 (LE LE01055650
http://en.herbariumle.ru/?t=occ&id=7320); additional herbarium
specimens prepared on 13 May 2019 by L. Averyanov and T. Maisak,
CPC 8001a, flowers odorless, tepals grassy green, lip white with small
sparse deep purple marks, column and anther white (LE LE01055080
http://en.herbariumle.ru/?t=occ&id=5561, LE LE01055649
http://en.herbariumle.ru/?t=occ&id=7319); Plate – d-EXSICCATES
OF VIETNAMESE FLORA 0358 / CPC 8001a (Fig. 4, LE
LE01087362 http://en.herbariumle.ru/?t=occ&id=30039). Lao Cai
Province, Bat Xat District, Bat Xat Nature Reserve, 4 km SSE of Y Ty
Village, disturbed swampy forest, 22°37'30''N 103°37'28''E, elevation
1840 m, Nuraliev M.S. 2659, 7 June 2019 (LE LE01059480
http://en.herbariumle.ru/?t=occ&id=10036, LE LE01058723
http://en.herbariumle.ru/?t=occ&id=9376; MW).
Dendrobium praecinctum Rchb.f. 1877, Gard. Chron.,
n.s., 7: 750; Seidenfaden, 1995, Opera Bot. 124: 28;
Pearce, Cribb, 2002, Orchids of Bhutan: 416, pl. 23; Jin
Xiao-Hua et al., 2010, Acta Bot. Yunnan. 4: 333; Zhou
et al., 2016, Phytotaxa 276: 50. Origin of the type
unknown. Type – “cult. Veitch” (W – Herb. No. 39641).
Fig. 6A-C
= Dendrobium pauciflorum King & Pantl. ex King, 1896, J. Asiat.
Soc. Bengal, Pt. 2, Nat. Hist. 64: 332; King & Pantl., 1898, Ann.
Roy. Bot. Gard. Calcutta 8: 54, pl. 76; Seidenfaden, 1985, Opera
Bot. 83: 97, fig. 57, pl. 12C.
Described from NE India (“Sikkim above Engo, at
an elevation of about 4,000 feet; in flower in June.”).
Type not located (CAL?).
Habitat, phenology and conservation status (in
Vietnam). Epiphyte on tall trees. Evergreen broad-
leaved montane forests. Flowers in June–July. Very rare.
Estimated IUCN Red List status: DD.
Distribution: Vietnam (NW: Lai Chau Province; in
addition one unlocalised specimen from the country).
Bhutan, NE India, N Myanmar, N Thailand, S China
(Yunnan Province).
Notes. With respect to its distribution, D.
praecinctum is a typical East Himalayan species. The
discovered locations of this species in Vietnam represent
the southeastern limit of its distribution.
Studied specimens. Vietnam, sine loc., cult. in Pleicu Town,
21 July 2016, Cong Danh Vo, s.n. (LE photo LE01087334
http://en.herbariumle.ru/?t=occ&id=28548). NW Vietnam, Lai Chau
Province, 29.06.2020, Nguyen Van Canh, s.n. (LE photo LE01087080
http://en.herbariumle.ru/?t=occ&id=18174).
Neottianthe secundiflora (Kraenzl.) Schltr. 1919, Repert.
Spec. Nov. Regni Veg. 16: 291; Pearce, Cribb, 2002,
Orchids of Bhutan: 172; Chen et al., 2009, Flora of China
25: 132, fig. 178 (12–15); Rokaya et al., 2013, Nord. J.
Bot. 31: 537; Jalal, Jayanthi, 2015, Lankesteriana 15, 1:
34; Zhou et al., 2016, Phytotaxa 276: 93.
Fig. 6D-H
≡ Peristylus secundiflorus Kraenzl., 1898, Orchid. Gen. Sp. 1: 518.
≡ Ponerorchis secundiflora (Kraenzl.) X.H. Jin, Schuit. & W.T. Jin,
2014, Molec. Phylogen. Evol. 77: 51.

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Fig. 5. New orchids in the flora of Vietnam. Collabium yunnanense Ormerod. Analytical plate (d-EXSICCATES OF VIETNAMESE FLORA
0358 / CPC 8001a) corresponding to the herbarium specimen CPC 8001a. All photos by L. Averyanov, design by L. Averyanov and T. Maisak.

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Fig. 6. New orchids in the flora of Vietnam. Dendrobium praecinctum Rchb.f. (A-C) and Neottianthe secundiflora (Kraenzl.) Schltr.
(D-H). A, B. Photos by Cong Danh Vo (21 July 2016, Cong Danh Vo s.n.). C. Photo by Nguyen Van Canh (29 Jun 2020, Nguyen Van
Canh, s.n.). D. Plant prior to the preparation of a voucher specimen. E, F. Tubers and basal portion of the stem. G. Apical portion of
inflorescence. H. Flowers, half-side view and view from below. Photos by Truong Ba Vuong from the specimen AL 1239, design by
L. Averyanov and T. Maisak.
≡ Habenaria secundiflora Hook.f., 1890, Fl. Brit. India 6: 165; id.,
1895, Icon. Pl. 24, tab. 2321, nom. illeg., non Barbosa Rodr., 1881.
Described from the Himalayas (“Subalpiner Teil des Himalaya,
3000–3300 m; … Sikkim 4400 m; … Chumbi”). Syntypes – NW
India, Kumaon, J.F. Duthie 3421 (K000796374
https://apps.kew.org/herbcat/getImage.do?imageBarcode=K0007
96374); NE India, Sikkim, Hooker 278 (K000974209
https://apps.kew.org/herbcat/getImage.do?imageBarcode=K0009
74209); China, Tibet, Chumbi, Dungboo s.n. (K000796373
https://apps.kew.org/herbcat/getImage.do?imageBarcode=K0007
96373).
Habitat, phenology (in Vietnam) and conservation
status. Terrestrial tuberiferous herb. Open mossy and
grassy slopes in humid evergreen broad-leaved montane
forest at elevations of 2000–3000 m. Flowers in June–
July. Very rare. Estimated IUCN Red List status: DD.
Distribution. NW Vietnam (Lao Cai Province,
Fansipan Mountain). Bhutan, Nepal, N India, N Myanmar,
S China (Sichuan, Yunnan, Xizang provinces).
Notes. Neottianthe secundiflora in its distribution
and ecology is a typical species of the subalpine
subtropical zone of the high Himalayas. The remarkable
discovery of this species in Vietnam considerably
expands its known distribution area in the SE direction.
This fact also provides an additional evidence for the not
yet fully uncovered richness of the flora of the highest
mountain peaks of NW Vietnam in subtropical and
temperate floristic elements. In this connection, such
highland areas play a role of unique disjunctive refuges
of subtropical and temperate plant species within the
tropical latitudes.
Studied specimen. Vietnam, Lao Cai Province, Fansipan
Mountain, 23 June 2019, Truong Ba Vuong, Nguyen Thanh Luan, AL
1239 (LE LE01066673 http://en.herbariumle.ru/?t=occ&id=12431).

2020 Averyanove et al. : New Orchids in the Flora of Vietnam
487
Nervilia appressifolia Aver. & V.C. Nguyen, sp. nov.
Figs. 7-9
Described from S Vietnam. Type: VIETNAM, Dak
Lak Province, Yok Don National Park, open dipterocarp
forest and woodlands with low bamboo at elevations of
200–300 m a.s.l., terrestrial tuberiferous herb in
seasonally flooded and wet soil, very rare, 7 June 2019,
Nguyen Van Canh, AL 1109 (holotype – LE LE01076868,
http://en.herbariumle.ru/?t=occ&id=19023). Photos of
living plants used for the preparation of the type specimen
- LE LE01087399
(http://en.herbariumle.ru/?t=occ&id=38798). Photos of
liquid preserved specimen and floral parts used for the
preparation of the type specimen – LE LE01087291
(http://en.herbariumle.ru/?t=occ&id=19013).
Etymology. The species name refers to the leaf blade
tightly appressed to the ground.
Description. Herb ephemeroid, terrestrial,
tuberiferous, stoloniferous, leafless at anthesis, forming
leaves after flowering, glabrous. Tuber underground,
globular, (4.5)5–6(6.5) mm in diameter, annually
substituting, with few short finger-like outgrowths,
producing stem at base. Stem underground, erect or
suberect, sparsely verruculose, ebracteate, (7)9–18(20)
mm long, (0.9)1–1.1(1.2) mm in diameter (in liquid
preserved material); at anthesis bearing a terminal
peduncle and a lateral vegetative bud covered by 1–2
small scarious bracts; after anthesis bearing a single leaf,
epigeous stolons and infructescence (when fruits are
developed). Hypogeous stolons arising from tuber
outgrowths or from underground portion of stem, white,
(3)4–10(14) mm long, about 1 mm in diameter, forming
at apex a tuber of an individual plant of the next
generation. Epigeous stolons horizontal, creeping,
appressed to the ground, light greenish, up to 12 cm long,
0.8–1 mm in diameter, forming new plants at nodes.
Leaves sessile or subsessile, with petiole less than 1.5
mm long; leaf blade cordate to orbicular or reniform,
convex, umbrella-shaped, (1.2)1.5–2.4(2.6) cm in
diameter, blunt or broadly obtuse at apex, margin entire,
with 5–11(13) arcuate main veins, tightly appressed to
the ground. Inflorescence 1-flowered; peduncle erect,
pale olive greenish, (3.5)4–6(6.5) cm long, (0.8)0.9–
1(1.1) mm in diameter, at middle with 1–2 broad tubular
obtuse scarious sterile bracts (5)7–12(14) mm long, 2–3
mm wide (when flattened); floral bracts inconspicuous,
broadly triangular, less than 1 mm long. Flowers nutant,
not widely opening. Sepals and petals subsimilar,
broadly lanceolate or narrowly elliptic, shallowly
cymbiform, almost straight, pale olive greenish,
(7.5)7.8–8.2(8.4) mm long, (1.6)1.8–2(2.2) mm wide,
acute at apex, 3-veined. Lip 3-lobed, pandurate in outline,
(7.8)8–8.2(8.4) mm long, (2.4)2.6–2.8(3) mm wide; side
lobes narrowly rectangular or narrowly obtriangular,
erect and embracing column, green, 3–3.4 mm long, 0.7–
0.8 mm wide, obtuse or blunt at apex; median lobe
obovate, conduplicately folded, (3.4)3.6–4(4.2) mm long,
(2.4)2.6–2.8(3) mm wide (when flattened), apex blunt to
roundish, white and sparsely speckled with purple, on
adaxial surface bearing a fleshy papillose longitudinal
ridge, its proximal part forked into 2 low keels running
to middle of hypochile; lip abaxially with narrow
longitudinal groove running along almost its entire
length. Column simple, erect, stout, clavate, dorsally
prominently gibbous, light greenish, (4.2)4.4–4.5(4.6)
mm long, 1.2–1.4 mm wide; anther cap helmet-shaped,
subquadrate at front view, white to light pinkish, 0.8–0.9
mm long and wide; stigma concave, triangular obovate;
rostellum inconspicuous, in form of two lateral
horizontal teeth meeting above stigma. Ovary ovoid,
olive brown, (2)2.2–2.5(2.6) mm long, (1.2)1.4–1.5(1.6)
mm in diameter, shallowly longitudinally grooved. Fruit
unknown.
Habitat, phenology and conservation status.
Terrestrial tuberiferous ephemeroid herb growing on wet
lateritic soil at the bottom of small occasionally flooded
(during torrential rains) puddles in open semideciduous
seasonally flooded dipterocarp forest and woodland with
domination of small bamboo, at elevations of 200–300
m a.s.l. Flowers in May–June. Very rare. Estimated
IUCN Red List status: DD.
Distribution. S Vietnam (Dak Lak Province, Yok
Don National Park). Endemic to S Vietnam.
Notes. The discovered plant belongs to a group of
species of the genus Nervilia with 1-flowered
inflorescence and 3-lobed lip more or less hairy or
papillulate in the center. In mainland Asia this group is
represented by N. calcicola Kerr, N. infundibulifolia
Blatt. & McCann, N. punctata (Blume) Makino and N.
viridiflora Q. Liu & J.W. Li. Among them, the new
species is closest in its floral morphology to N.
viridiflora which is endemic to southern Yunnan (Tang
et al., 2018), but differs in smaller floral bract less than
1 mm long (vs. 5–6 mm long), smaller, nutant, not
widely opening flowers with sepals and petals 7.5–8.4
mm long (vs. flowers larger, suberect, widely opening,
with sepals and petals 13–18 mm long), lip with obovate
or narrowly obovate, obtuse median lobe, as wide as or
narrower than the hypochile (vs. median lobe orbicular,
emarginate, broader than the hypochile), conduplicately
folded (vs. almost flat) lip, and median lobe of the lip
with conspicuous tall papillose ridge (vs. median lobe
with two insignificant low glabrous keels). At the same
time, N. appressifolia strikingly differs from almost all
known congeners in the sessile leaf tightly appressed to
the ground, long green epigeous stolons and in its habitat
at the moist bottom of temporary flooded puddles. Such
narrow ecological preferences are not found in any other
known species of the genus.
Nervilia appressifolia is presently known
exclusively from a very limited area in Yok Don
National Park in Dak Lak Province of southern Vietnam.

Taiwania Vol. 65, No. 4
488
Fig. 7. New orchids in the flora of Vietnam. Nervilia appressifolia Aver. & V.C. Nguyen. A. Habitat at locus classicus. B. Flowering
plant. C. Flower. D. Sepals, petals, lip, column with ovary and peduncle. E. Lip in natural position, adaxial, side and abaxial views. F.
Plants growing on the bed of a small temporary flooded pool. G. Typical group of plants in the locus classicus. H. Plant with epigeous
stolons. I, J. Plants with different colour and shape of the leaf blade. B–E: Photos of plants used for the preparation of the type (AL
1109). F–J: Photos of plants used for the preparation of one of the paratypes (AL 1167). Photos by L. Averyanov (A, F–J) and Van
Canh Nguyen (B–E), design by L. Averyanov and T. Maisak.

2020 Averyanove et al. : New Orchids in the Flora of Vietnam
489
Fig. 8. New orchids in the flora of Vietnam. Nervilia appressifolia Aver. & V.C. Nguyen. A. Flowering plants. B. Leaf blade, adaxial
and abaxial views. C, D. Flowers, front view. E. Sepals and petals, view from behind. F. Column and lip, side view. G, H. Lip, half-side
view. I. Lip, view from below. J–L. Flattened lip, adaxial side. M–P. Column, front, half-side, side views, and view from behind. Q–S.
Column apex and anther, side, half-side views, and view from behind. T. Papillose margin of lip epichile. U, V. Keel on adaxial surface
of the lip, in apical part of epichile (U) and at its base (V). Photos by L. Averyanov from liquid preserved plants used for the preparation
of the type specimen AL 1109. Design by L. Averyanov and T. Maisak.

Taiwania Vol. 65, No. 4
490
Fig. 9. New orchids in the flora of Vietnam. Nervilia appressifolia Aver. & V.C. Nguyen. A. Plants with stolons. B. Leaf, adaxial view.
C. Plant with stolons, view from below. D. Flowering plants. E. Apical part of inflorescence, side view. F. Sepals and petals with ovary,
front view (lip and column removed). G, H. Flattened lip, adaxial (G) and abaxial side (H). I. Flattened lip, adaxial side and transversal
sections. J. Lip in natural position, side view. K. Lip in natural position, top view. L. Lip in natural position, sagittal section. M. Lip in
natural position, half side view from below. N. Column, front, half-side, side views, and view from behind. Drawn from the paratype AL
1167 (A–C) and the holotype AL 1109 (D–N) by L. Averyanov and T. Maisak.

2020 Averyanove et al. : New Orchids in the Flora of Vietnam
491
The observed population occupies an area of not more
than 500 m2. The attribution of a conservation status to
this very rare plant in terms and criteria proposed by
IUCN Red List requires additional field studies in the
putative area of its distribution. The present IUCN
conservation status is preliminarily estimated as “Data
Deficient” (DD).
Studied specimens (paratypes). S Vietnam, Dak Lak
Province, Buon Don District, Yok Don National Park, open dry dipterocarp
forest and woodland, terrestrial ephemeroid tuberiferous herb with prostrate
green or dark green leaves in open grassy place, at elevation of 200–300 m
a.s.l., locally abundant, 10 October 2017, N.V. Canh, AL 316 (LE
LE01074054, http://en.herbariumle.ru/?t=occ&id=19021). Yok Don
National Park, open dry dipterocarp forest, 3 June 2018, Nguyen Van Canh
s.n. (photos – LE LE01087398, http://en.herbariumle.ru/?t=occ&id=38797).
Yok Don National Park, open dry dipterocarp forest, 30 August 2018,
Nguyen Van Canh s.n. (photos – LE LE01087397,
http://en.herbariumle.ru/?t=occ&id=38796) and Dinh Quang Diep, s.n.
(photos – LE LE01087292, http://en.herbariumle.ru/?t=occ&id=19014).
Yok Don National Park, open dry dipterocarp forest and woodland
with dense low bamboo, at an elevation of 200–300 m a.s.l., terrestrial
ephemeroid tuberiferous herb with prostrate leaves in open wet place,
very rare, found in one location, 24 October 2019, L. Averyanov,
Nguyen Van Canh, T. Maisak, AL 1167 (LE LE01066622,
http://en.herbariumle.ru/?t=occ&id=12390).
ACKNOWLEDGMENTS
The studies were supported in parts by the Russian
Foundation for Basic Research, projects 19-54-54007 & 20-04-
00339, and 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). We thank Mr.
Cong Van Vo for access to his private orchid collection and
photos of Dendrobium praecinctum, Dr. Pankaj Kumar for his
kind help in plant identification and Prof. D.D. Sokoloff for his
ideas on the morphology of the flower of Apetalanthe.
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