Bulbophyllum sridithii (Orchidaceae), new species from Vietnam

Abstract

Bulbophyllum sridithii a new species to science is described and illustrated from Kon Ka Kinh National Park of Vietnam. The new species belongs to the section Cirrhopetaloides and resembles B. layae, B. hirundinis, B. electrinum, B. pecten-veneris and B. tingabarinum but differs in the size and shape of pseudobulbs, the shape of the leaf blade, and flower size. Morphological description, illustrations, data on habitat, phenology, and conservation status are provided.

Full text

Taiwania 65(4): 473‒477, 2020
DOI: 10.6165/tai.2020.65.473
473
Bulbophyllum sridithii (Orchidaceae), new species from Vietnam
Ba Vuong TRUONG1,2,*, Van Son DANG1, 2, Hop TRAN3, Tatiana V. MAISAK4, Leonid V. AVERYANOV4
1. Graduate University of Science and Technology, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay
District, Hanoi, Vietnam.
2. Institute of Tropical Biology, Vietnam Academy of Science and Technology, 85 Tran Quoc Toan Street, District 3, Ho Chi Minh
City, Vietnam.
3. 480A Le Van Sy Street, District 3, Ho Chi Minh City, Vietnam.
4. Komarov Botanical Institute, Russian Academy of Sciences, Prof. Popov Street 2, 197376, St. Petersburg, Russia.
Corresponding author’s email: bavuong2019@yahoo.com
(Manuscript received 1 July 2020; Accepted 28 September 2020; Online published 3 October 2020)
ABSTRACT: Bulbophyllum sridithii a new species to science is described and illustrated from Kon Ka Kinh National Park of
Vietnam. The new species belongs to the section Cirrhopetaloides and resembles B. layae, B. hirundinis, B. electrinum, B. pecten-
veneris and B. tingabarinum but differs in the size and shape of pseudobulbs, the shape of the leaf blade, and flower size.
Morphological description, illustrations, data on habitat, phenology, and conservation status are provided.
KEY WORDS: Cirrhopetaloides, endemism, Kon Ka Kinh National Park, new orchid species, plant diversity, plant taxonomy.
INTRODUCTION
The genus Bulbophyllum Thouars (1822) is one of
the largest plant genera, with over 2200 species
distributed in tropics and subtropics of the world
(Vermeulen et al., 2014). Currently, more than 145
species from 15 sections have been recorded in Vietnam
(Seidenfaden, 1992; Averyanov, 1994; Averyanov and
Averyanova, 2003; Averyanov et al., 2015, 2016, 2018,
2019a,b; Nong and Averyanov, 2015; Nguyen and
Averyanov, 2017; Truong et al., 2019a-c).
The new species according to its morphology
belongs to Bulbophyllum section Cirrhopetaloides
Garay, Hamer & Sigerist (Vermeulen et al., 2014), and
is characterized by creeping rhizome; 1-leaved
pseudobulbs; subumbellate raceme arising from the base
of pseudobulbs; free dorsal sepal, entire, erose, fimbriate,
ciliate, or paleate along the margin; lateral sepals twisted
at the base and adnate (entirely or in part) along one or
both margins. Petals are denticulate or fimbriate along
the margin, lip simple, entire; stelidia usually shorter
about half of the column length. Pollinia 4, without stipe.
During the botanical survey in Kon Ka Kinh National
Park, an unknown miniature Bulbophyllum species
belonging to the section Cirrhopetaloides, was found.
After careful examination of available taxonomic
literature, herbarium specimens from VNM, HN, VNMN,
as well as herbaria images presented in JSTOR website,
LE, K and P databases, we concluded that this species is
new for science. It is described and illustrated below.
MATERIALS AND METHODS
The measurements and species description made
from living plants. Type herbarium and additional liquid
fixed material (preserved in 70% ethanol) are stored at
VNM herbarium (ITB - Ho Chi Minh City). All the
photos were taken with a Canon 600D fitted with an EF–
S 60mm f/2.8 Macro USM lens. The terminology for the
morphological description follows Beentje (2012).
TAXONOMIC TREATMENT
Bulbophyllum sridithii Vuong, Aver., H. Tran & V.S.
Dang, sp. nov.
Fig. 1–3
(B. sect. Cirrhopetaloides Garay, Hamer & Sigerist)
Type: VIETNAM, Gia Lai Province, K’Bang District,
Son Lang Commune, Ha Lam Village, Kon Ka Kinh
National Park, 11 December 2019, Truong Ba Vuong,
Dang Van Son, BV 459 (holotype: VNM00023643!, photo
- LE, http://en.herbariumle.ru/?t=occ&id=17658, analytical
photo-plate - LE, http://en.herbariumle.ru/?t=occ&id=17630).
Description: Herb epiphytic, perennial, rhizomatous.
Rhizome creeping, stout, ca. 1.5 mm in diameter,
brownish-grey, with single-leafed pseudobulbs.
Pseudobulbs close to each other or distant ca. 2 mm,
glossy green, broadly ovoid to globose, 6–7 mm tall, ca.
7 mm in diameter. Leaves sessile or subsessile, elliptic,
2.4–3 cm long, 1–1.5 cm wide, apex obtuse, leaf blade
narrowing at base into short petiole ca. 2 mm long,
twisted, with distinct articulation at base. Inflorescence
arising from the base of pseudobulb, umbel-like raceme,
with (1)3–4 flowers; scape suberect, slender, 2–2.5 cm
long, at base covered by 2 to 3 brownish, tubular,
papyraceous sheaths, 1–4 mm long; floral bracts
triangular, 2.8–3 mm long, apex acuminate; pedicel with
ovary 7–8 mm long; ovary with 6 longitudinal grooves.
Flowers red, opening simultaneously. Dorsal sepal
broadly ovate, 3–3.5 mm long, ca. 2 mm wide, concave,

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Fig. 1. Bulbophyllum sridithii. A & B: Flattened flowering and fruiting plants. C: Intact flowering plant. D & E: Intact inflorescences,
frontal and half-side views. F: flattened inflorescence. G: Floral bract. H: Flowers, views from different sides. I: Flower with intact
median sepal, base of lateral sepals, petals and lip, frontal view. J: Flower with sepals removed, side view. L: Median sepal, frontal
view, side view, and view from behind. M: Flattened petals. N: Lip, frontal fief, half-side view, and view from below. O: Column, side,
and half-side views. P: Anther cap, view from above and from below. Q: Pollinia from different views. All photos taken by Truong Ba
Vuong (made from specimen used for the holotype preparation, BV 459), correction, and design by L. Averyanov and T. Maisak.

2020 Truong et al. : New species from Vietnam, Bulbophyllum sridithii
475
Fig. 2. Bulbophyllum sridithii. A: Flower, half-side view and view from behind. B: Flattened sepals and petals. C: Lip, frontal view.
D: Lip, view from behind. E: Column, half-side view. F: Column, ovary and pedicel, side view. G: Anther cap, half-side view. H: Anther
cap, abaxial and adaxial surface. I: Pollinia, frontal view and view from behind. Drawing by Truong Ba Vuong from the holotype
specimen, BV 459, graphic correction by L. Averyanov.

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Fig. 3. Bulbophyllum sridithii. Holotype specimen, BV 459 housed at VNM (VNM00023643).
3-veined, margin fimbriate, apex shortly abruptly
acuminate. Lateral sepals somewhat fleshy, ca. 20 mm
long, 3 mm wide (at base) adnate to column foot, lower
margins joined in basal third, upper margin twisted and
free at base, then fuse together (ca. 3.5 mm long), toward
the apex attenuate into filiform caudate free part. Petals
ovate, slightly oblique, 2.5–2.8 mm long, 1.5–1.8 mm
wide, 3-veined, apex obtuse, margin fimbriate. Lip
simple, fleshy, ca. 2 mm long, 1 mm wide, narrowly
triangular, recurved at middle, at base channeled,
adaxially with low median keel from base to the apex,
median ridge on abaxial surface runs from the labellum
base to the apex, margin revolute, finely hairy at the lip
base. Column ca. 1 mm tall, column foot ca. 4 mm long,
upcurved; stelidia slender, subulate, straight or somewhat
falcate, ca. 0.5 mm long; anther cap rectangular in outline,
ca. 0.7 cm long, 0.6 cm wide, laterally somewhat concave,
with yellowish brown callus at front. Pollinia 4. Capsule
fusiform, ca. 1.6 cm long.
Etymology: The species epithet refers to the name of
Professor Kitichate Sridith, famous researcher of
Indochinese flora.
Habitat and phenology: Clustering miniature branch
epiphyte growing in evergreen broad-leaved
submontane seasonal forests. Rare. Flowers in
December to January.
Distribution: VIETNAM, Gia Lai Province (Kon Ka
Kinh National Park). Endemic of southern Vietnam in
limits of Central Highlands (Tay Nguyen Plateau).
Taxonomic notes: The new species resembles
Bulbophyllum layae Aver. & Vuong described in 2019
from northern Vietnam (Averyanov et al., 2019a) but
differs in dorsal sepal broadly ovate suddenly narrowing
into shortly acuminate apex (vs. narrowly ovate,
gradually tapering into attenuate apex), the lower margin
of lateral sepals adnate from the base to nearly one third
of their length (vs. the lower margin almost free from the
base), petals ovate (vs. petals narrowly ovate); stelidia
porrect, falcate, slightly downward (vs. stelidia erect,
slender, straight forward directed). Moreover, the new
species is additionally separated from above species in
broadly ovoid or globular pseudobulbs (vs. pseudobulbs
ovoid to narrowly ovoid), leaves elliptic 2.4–3 cm long,
1–1.5 cm wide (vs. leaves lanceolate or oblong
lanceolate, 3.5–6 cm long, 4.5–7 mm wide), small
flowers less than 2.5 cm long (vs. flowers 2.5–3 cm long),
The new described species resembles to B.
electrinum Seidenf. but can be distinguished by the short
inflorescence 2–2.5 cm, with up to 4 flowers (vs.
inflorescence up to 13 cm long, with up to 11 flowers),
lip finely ciliate along the margin at the base (vs. lip
glabrous), stelidia porrect, falcate, slightly downward

2020 Truong et al. : New species from Vietnam, Bulbophyllum sridithii
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(vs. stelidia very slender, filiform, erect), anther cap
glabrous with brown callus at front (vs. anther cap
papillose, without callus at front).
In addition, B. sridithii resembles to B. hirundinis
(Gagnep.) Seidenf. but clearly differs by pseudobulbs
placed close together or distant on less than 2 mm (vs.
pseudobulbs distant on about 15 mm), inflorescence 2–
2.5 cm, with up to 4 flowers (vs. inflorescence 3–4 cm
long, with up to 11 flowers), lip at base ciliate along the
margin (vs. lip glabrous).
Furthermore, the new species resembles to the B.
pecten-veneris (Gagnep.) Seidenf. and B. tingabarinum
Garay, Hamer & Siegerist but recognized by inflorescence
2–2.5 cm long (vs. inflorescence up to 15 cm long), lateral
sepals ca. 2 cm long, lower margin fused at basal third (vs.
lateral sepals up to 7.5 cm long, lower margin free at base),
lip at base densely hairy along the margin (vs. lip glabrous).
Studied specimen (paratype): VIETNAM, herbarium
specimen prepared in 11 January 2020, Truong Ba Vuong, Dang Van
Son, BV 483 (VNM VNM00023648!) from cultivated plant, originated
from Gia Lai Province, K’Bang District, Son Lang Commune, Ha Lam
Village, Kon Ka Kinh National Park).
ACKNOWLEDGMENTS
The authors would like to express their sincere gratitude to
the reviewers for their critical suggestions which are helpful in
improvement the manuscript. Field and laboratory studies were
supported by Herbarium of Institute of Tropical Biology, Ho
Chi Minh City. The work on this publication was supported in
part by the RFBR “Inventory, taxonomy and geography of the
orchids (Orchidaceae) of Vietnam”, 20-04-00339 А.
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