A new spotted Chiloschista (Orchidaceae: Aeridinae) from Bhutan

Abstract

A new species of Chiloschista from a restricted area in Bhutan is described and illustrated. It is compared with C. parishii from Myanmar and Thailand, which has similarly colored flowers and from which it differs by the larger flowers, 15–18 mm versus 8–10 mm, and the lack of a glandular and pubescent, erect and curved callus lobe inside the lip, which is generally seen in other similarly colored species of this genus. Key Words: Aeridinae, Bhutan, Himalaya, new Chiloschista, Orchidaceae, Vandeae

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LANKESTERIANA 19(1): 23—29. 2019.
A NEW SPOTTED CHILOSCHISTA (ORCHIDACEAE: AERIDINAE)
FROM BHUTAN
Choki Gyeltshen1, stiG Dalström2.5, nima Gyeltshen3 & kezanG tobGay4
1 Senior Biodiversity Ofcer, National Biodiversity Centre, Ministry of Agriculture and Forests,
Serbithang, Thimphu, Royal Government of Bhutan
2 2304 Ringling Boulevard, unit 119, Sarasota FL 34237, USA; Lankester Botanical Garden,
University of Costa Rica, Cartago, Costa Rica; National Biodiversity Centre, Serbithang,
Royal Government of Bhutan
3 Biodiversity Supervisor, Royal Botanic Garden, National Biodiversity Centre,
Ministry of Agriculture and Forests, Serbithang, Thimphu, Royal Government of Bhutan
4 Biodiversity Ofcer, Royal Botanic Garden, National Biodiversity Centre, Serbithang, Thimphu,
Royal Government of Bhutan
5 Corresponding author: stigdalstrom@gmail.com
AbstrAct. A new species of Chiloschista from a restricted area in Bhutan is described and illustrated. It is
compared with C. parishii from Myanmar and Thailand, which has similarly colored owers and from which
it differs by the larger owers, 15–18 mm versus 8–10 mm, and the lack of a glandular and pubescent, erect
and curved callus lobe inside the lip, which is generally seen in other similarly colored species of this genus.
Key Words: Aeridinae, Bhutan, Himalaya, new Chiloschista, Orchidaceae, Vandeae
doi: http://dx.doi.org/10.15517/lank.v19i1.37030
Introduction. During an orchid inventory in the
southern part of Bhutan in May 2014 by a research
team from the National Biodiversity Centre in
Serbithang, Bhutan (NBC), plants of a Chiloschista
Lindl., species without flowers were found growing
as epiphytes on small trees in deep shade near the
Gelephu Tshachu, or hot springs, just north of the
city of Gelephu in the Sarpang District near the
Indian border (Fig. 1–2). A few plants were collected
for cultivation at the Royal Botanic Garden in
Serbithang where one plant flowered in May the
following year (Fig. 3–4). The identity of this plant
turned out to be unknown and after some research
it was concluded that it represented a new species.
The flowers are yellow with brown spots like
many other members of this genus but the internal
structure of the lip is distinct from other similar-
looking species. Based on what appears primarily
to be the color pattern of the sepals and petals,
several other species have been incorrectly treated
mainly as Chiloschista lunifera (Rchb.f.) J.J.Sm,
or as Chiloschista parishii Seidenf., (Fig. 5–6)
in the past. In an attempt to avoid adding further
confusion to the rather complex history of these and
similar species at this time, we refer here to Gunnar
Seidenfaden’s discussion about this subject and his
description of C. parishii (Seidenfaden 1988). For
readers who do not have access to this publication
we summarize some of Seidenfaden’s reasoning
here: “The file folder with Thrixspermum luniferum
in Herb. Reichenbach [today inserted in the general
herbarium at the Museum of Natural History in
Vienna, Austria] contains a mixture of two species.
The type is represented by a sheet (41550b)
with some inflorescences sent by Veitch; this is
supplemented by coloured sketches (41549, left
hand), accompanied by the handwritten diagnosis.
The other material consists of a flowerless plant of
Parish, no. 55 (26237) from Moulmein, accompanied
by Parish’s coloured drawing (11583); this is the one
Reichenbach published as Thrixspermum luniferum
in 1874 [Reichenbach did not refer to Parish 55
specifically but listed Thrixspermum luniferum,
described by him in 1868 and sent to him by
Veitch, as having been collected by Parish simply
by including this species in the 1874 publication,
which was dedicated to Parish’s collections in the
Moulmein area of Myanmar]. There is a flowering
plant received from Low, collected by Boxall in
1879 (41550a), this is sketched in colour (41549,
Received 19 March 2019; accepted for publication 24 April 2019. First published online: 29 April 2019.
Licensed under a Creative Commons Attribution-NonCommercial-No Derivs 3.0 Costa Rica License.

LANKESTERIANA 19(1). 2019. © Universidad de Costa Rica, 2019.
24 LANKESTERIANA
right hand). All this material is not Chiloschista
lunifera, see C. parishii below. When Hooker f. in
1890 recorded Sarcochilus luniferus he had no access
to Reichenbach’s herbarium [which was locked up
for 25 years since 1889]. But he had a specimen
of Parish no. 55 and was misled by Reichenbach’s
publication of 1874. Most later authors are equally
wrong when they record a ‘lunifera’.” (Seidenfaden
1988).
Seidenfaden (1988) continues with describing
Chiloschista parishii based on Parish’s collection
#55 and adds: “This is the plant fully described by
earlier authors under the name Sarcochilus luniferus
or Chiloschista lunifera. As earlier explained,
Reichenbach in 1874 made a mistake in referring a
Parish plant to Thrixspermum luniferum, and with the
closing of his herbarium that plant was the only one
available to Hooker f.”
We realize that the name “Chiloschista parishii”
is frequently used in various publications for species
that share the coloration of the owers (yellow with
brown spots) but differ in other characteristics and
in reality represent different species (Pearce & Cribb
2002, Gurung 2006, Raskoti 2009) some of which
remain to be scientically described and named. It
is not the present authors’ ambition to deal with that
subject in this current paper, but we will focus on some
of these other species in future articles when more
material is available. The original collection of what
became Chiloschista parishii was made by Reverend
Charles Samuel Pollock Parish (#55), presumably in
the “Moulmein” area of Myanmar. For some reason
unknown to us, his name’s initials are listed as “E.
FiGure 1. Map of Bhutan indicating the place of the type
collection of Chiloschista gelephuense near the Gelephu
Tshachu hot springs.
FiGure 2. Chiloschista gelephuense grows as an epiphyte along the Mo Chu River, north of the city of Gelephu.

Gyeltshen et Al. — A new Chiloschista 25
LANKESTERIANA 19(1). 2019. © Universidad de Costa Rica, 2019.
C.” rather than C. S. P. Parish in the Transactions
of the Linnean Society publication (Reichenbach
1874). In any case, a drawing of this plant exists
in the herbarium of the Museum of Natural History
in Vienna, and is dated May 14, 1869 (W11583).
Gunnar Seidenfaden honored Parish by naming this
species after him and basing his description on the
ower-less specimen in Vienna (W26237) and the
colored drawing by Parish (W11583) as the holotype.
Chiloschista parishii is illustrated in Seidenfaden’s
treatment (1988) based on a collection from Doi
Saket in Thailand (“GT 7403, C!”; Seidenfaden
1988). Plants that were later identied as Chiloschista
parishii (Fig. 6) were observed by author Dalström
and others at a local market near the border between
Thailand and Myanmar 2009. These plants were
collected in Myanmar according to the people who
were selling them.
taxonomiC treatment
Chiloschista gelephuense Ch.Gyeltshen & Dalström,
sp. nov.
TYPE: Bhutan. Gelephu: North of Gelephu Tshachu
hot springs along road to the abandoned limestone
quarry, N26°56’50”; E90°30’41”, alt. ca. 300 m,
epiphytic in shade on smaller trees, collected on 12
May, 2014, and owered in cultivation at the Royal
Botanic Garden, Serbithang, 12 May, 2015, S.
Dalström 4212 & Ch. Gyeltshen (holotype: THIM)
(Fig. 3–4).
DiaGnosis: Chiloschista gelephuense is supercially
similar to C. parishi in the yellowish owers with
brown spots on the sepals and petals, but differs by
the larger ower, 15–18 mm across versus 8–10 mm
across for the latter species. Chiloschista gelephuense
also differs from other similarly colored species in the
genus by the lack of a glandular pubescent, erect and
curved callus lobe inside the lip.
Epiphytic herb. Roots numerous, spreading, terete
to slightly attened, 2–3 mm in diameter. Stem reduced,
virtually absent. Leaves seasonal in the wild during
the rainy period, not seen on the type. Inorescence
sub-erect to pendent, 15–16 cm long, almost straight
to indistinctly exuous, micro-pubescent, laxly
many-owered; peduncle ca. 5 cm long; rachis ca.
10.5 cm long; bracts scale-like, narrowly acute,
3–4 mm long. Pedicel with ovary micro-pubescent,
5–6 mm long. Flower with rather at and spreading
lateral sepals and petals and with the dorsal slightly
bent forward over the column, 15–18 mm across;
dorsal sepal light yellow with distinct reddish brown
spots, externally basally micro-pubescent, apically
and internally glabrous, broadly elliptic, apically
indistinctly obtuse to rounded, 9–10 × 6.5–7.0 mm;
lateral sepals similar in color and pubescence, fused
basally along the column foot, indistinctly obliquely
obovate to broadly elliptic, apically rounded, 7.5–
8.0 × 5.5–6.2 mm; petals similar in color, glabrous,
sessile and fused to the column foot, subrectangular
to indistinctly obovate, apically rounded, 8.0–8.5
× 5.0–5.5 mm; lip externally whitish with a small
irregular brown marking at the tip of the front-lobe,
internally with dark red-brown stripes and markings,
FiGure 3. Chiloschista gelephuense owered in cultivation
at the Royal Botanic Garden, Serbithang, in May of
2015.

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26 LANKESTERIANA
FiGure 4. Chiloschista gelephuense Ch.Gyeltshen & Dalström. A. Plant habit. B. Flower in front angled view. C. Column
lateral view. D. Column and lip lateral view. E. Lip back (internal) view. F. Lip cleft, lateral view. G. Column ventral
view. H. Anther cap dorsal view. I. Pollinarium back view. J. Dissected ower. Drawn from the holotype by Stig
Dalström.

Gyeltshen et Al. — A new Chiloschista 27
LANKESTERIANA 19(1). 2019. © Universidad de Costa Rica, 2019.
FiGure 5. Chiloschista parishii Seidenfaden. A. Flower front angled view. B. column lateral view. C. Column ventral
view. D. Lip back (internal) view. E. Lip cleft, lateral view. F. Column and lip lateral view. G. Anther cap with pollinia
ventral view. H. Anther cap dorsal view. I. Stipe and viscidium back and front view. J. Dissected ower. Drawn from S.
Dalström 3023 (Dalström archives) by Stig Dalström.

rigidly attached to the column foot, deeply saccate
and slightly canaliculated ventrally, tri-lobed, lateral
lobes erect to indistinctly curved inwards, apically
rounded, front-lobe short, eshy, indistinctly bi-lobed
and labiate, slightly recurved, 6.0– 6.5mm high and
5.5–5.8 mm wide; callus a eshy, broad and micro-
pubescent swelling, from the base up to the base of
the front-lobe, with a pair of low more or less ovoid,
glandular pubescent swellings on each side, apically
divided into a pair of eshy knobs, with some
glandular micro-pubescence in between; column very
short and stocky, ca. 1.5–2.0 mm long, excluding the
anther cap and the column foot, 2.0–2.2 mm long;
anther cap light yellow, galeate with a pair of hair-
like, ca. 1 mm long tendrils on each side; pollinarium
of 2 obliquely globose and indistinctly attened,
cleft pollinia on a narrowly rectangulate triangular
stipe, ca. 1 mm long on a sub-quadrate, indistinctly
concave viscidium.
Distribution: Chiloschista gelephuense is currently
only known from the original type area near the
Tshachu hot springs north of the city of Gelephu in
FiGure 7. Natural habitat of Chiloschista gelephuense, growing epiphytically on Beaumontia grandiora (the messy looking
vine in the center), and on Aphanamixis polystachya to the right in this little cluster of trees.
LANKESTERIANA 19(1). 2019. © Universidad de Costa Rica, 2019.
28 LANKESTERIANA
FiGure 6. Chiloschista parishii from Myanmar, sold at a
local border market in western Thailand.

literature CiteD
FiGure 8. A plant of what is believed to be Chiloschista
gelephuense, growing on the trunk of Aphanamixis
polystachya near the type area.
southern Bhutan. No additional owering specimens
of Chiloschista gelephuense has been observed, only
plants in bud growing epiphytically on Beaumontia
grandiora Wall., (Apocynaceae) and Aphanamixis
polystachya (Wall.) Parker (Meliaceae) close to the
type locality (Fig. 7–8).
etymoloGy: Named in reference to the sub-district
(Dungkhag) of Gelephu, currently the only area where
this species has been found.
aCknowleDGments. The authors would like to thank Tashi
Y. Dorji, Program Director of the NBC, for her guidance
and support. We also thank Sangay Dema (NBC), and
Dupchu Wangdi (NBC) and Thomas Höijer for excellent
companionship in the eld. We sincerely thank the Sarasota
Orchid Society for continuous nancial support and Wesley
Higgins and the anonymous reviewers for improving the
manuscript. Finally we thank Sharon and Russell Stephens
of Sarasota, Florida, for contributing travel funds for the
second author through grant #20181806 from the Friends
of Orchid Research Fund, administrated by the Community
Foundation of Sarasota County.
Gyeltshen et Al. — A new Chiloschista 29
LANKESTERIANA 19(1). 2019. © Universidad de Costa Rica, 2019.
Gurung, D. B. (2006). An illustrated guide to the orchids of Bhutan. Thimphu, Bhutan: DSB Publication.
Pearce, N. R. & Cribb, P. J. (2002). The orchids of Bhutan. Royal Government of Bhutan: Royal Botanic Garden of
Edinburgh.
Raskoti, B. B. (2009). The orchids of Nepal. Kathmandu, Nepal: Published by Bhakta Bahadur Raskoti and Rita Ale.
Reichenbach, H. G. (1874). Enumeration of the orchids collected by the Rev. E. C. Parish in the neighbourhood of Moulmein.
The transactions of the Linnean society of London, 30(1), 133–156.
Seidenfaden, G. (1988). Chiloschista Lindl. Orchid genera in Thailand 14. Fifty-nine vandoid Genera. Opera Botanica, 95,
168–181.

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