Records of two extant orchid species (Orchidaceae) in Singapore

Abstract

I discovered overlooked materials when I reviewed the botanical spirit specimens from the herbarium of the Lee Kong Chian Natural History Museum, National University of Singapore. The materials are from two orchid species, Dendrobium singaporense and Bulbophyllum gusdorfii, which have been recently treated as nationally extinct in Singapore. Based on the materials I found, these species should be considered extant. However, they will soon again cross the threshold to being presumed nationally extinct, as the material discovered is from nearly 30 years ago. In Singapore, any species not seen in the wild for 30 years is categorised as nationally extinct.

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NATURE IN SINGAPORE 16: e2023023
Date of Publication: 15 March 2023
DOI: 10.26107/NIS-2023-0023
© National University of Singapore
Records of two extant orchid species (Orchidaceae) in Singapore
Matti A. Niissalo1
1Singapore Botanic Gardens, National Parks Board, 1 Cluny Road, Singapore 259569, Republic of Singapore; Email:
Matti_Asser_Niissalo@nparks.gov.sg
Abstract. I discovered overlooked materials when I reviewed the botanical spirit specimens from the herbarium of the
Lee Kong Chian Natural History Museum, National University of Singapore. The materials are from two orchid species,
Dendrobium singaporense and Bulbophyllum gusdorfii, which have been recently treated as nationally extinct in
Singapore. Based on the materials I found, these species should be considered extant. However, they will soon again cross
the threshold to being presumed nationally extinct, as the material discovered is from nearly 30 years ago. In Singapore,
any species not seen in the wild for 30 years is categorised as nationally extinct.
Key words. critically endangered, Dendrobium singaporense, Bulbophyllum gusdorfii
Recommended citation. Niissalo MA (2023) Records of two extant orchid species (Orchidaceae) in Singapore. Nature
in Singapore, 16: e2023023. DOI: 10.26107/NIS-2023-0023
INTRODUCTION
When going through spirit material which was recently moved from the herbarium of the Lee Kong Chian Natural
History Museum, National University of Singapore (SINU) to the Singapore Botanic Gardens’ herbarium (SING), I
encountered two orchid species (Dendrobium singaporense A.D.Hawkes & A.H.Heller and Bulbophyllum gusdorfii
J.J.Sm.) which were treated as nationally extinct in Lindsay et al. (2022). Bulbophyllum gusdorfii was reported in
Turner et al. (1995a, 1995b) when it was first recorded in Singapore. Chong et al. (2009) included it in their checklist as
did Davison et al. (2008) in the most recent Red Data Book. It was likely missed by Lindsay et al. (2022) because the
specimen could not be traced at the time. The rediscovery of Dendrobium singaporense does not seem to have been
reported in literature. As the spirit material at SINU was not consulted for Lindsay et al. (2022), its omission from the
checklist is expected.
SPECIMEN DETAILS
I compared both specimens with illustrations and descriptions in Seidenfaden & Wood (1992) to confirm their
identities. The spirit materials are illustrated in Fig. 1 (Dendrobium singaporense) and Fig. 2 (Bulbophyllum gusdorfii).
Dendrobium singaporense is unmistakable among Singapore and Peninsular Malaysian Dendrobium because of the
triangular apex of the flattened lip (see Fig. 1, I–J). Bulbophyllum gusdorfii has a unique combination of non-caudate
dorsal sepal and petals, each with long fine marginal ciliae, a column with short stelids; relatively broad, fused lateral
sepals; and petals with rounded tips. The details of all specimens from Singapore of these two species are shown in
Table 1.
CONSERVATION STATUS
The two species should currently be considered Critically Endangered, until thirty years has passed from the latest
collection from the field, which is the criterion for extinction (Davison et al., 2008). The last date that they may be seen
in the wild before being considered nationally extinct is 28 April 2023 for Bulbophyllum gusdorfii and 15 April 2024
for Dendrobium singaporense.

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Fig 1. Dendrobium singaporense. A, flower from front; B, flower from top; C, flower from side; D, column, column foot and lip,
with sepals and petals removed; E, flower from bottom; F, column and column foot; G, median sepal, abaxial side; H, petal, abaxial
side; I, lip, abaxial side; J, lip, adaxial side; K, lateral sepal, adaxial side (note the long cut part which connects to the column foot).
Both scale bars apply to all parts of the figure. All photos from H.T.W. Tan s.n. by Matti Niissalo.

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Fig. 2. Bulbophyllum gusdorfii. A, inflorescence; B, flower from front; C, flower from side; D, opened flower showing the column
and lip. All photos from K.S. Chua et al. NRS 1683 by Matti Niissalo.
Table 1. Records of Dendrobium singaporense and Bulbophyllum gusdorfii in Singapore (all except Thurston s.n. deposited in SING
at present).
Species
Collector(s)
name(s) and
number
Date of
collection
Locality
Notes
Dendrobium
singaporense
H.T.W. Tan s.n.
26 Jan
2001
Bukit Timah Nature
Reserve (= BTNR)
Flowers in spirit. “Nursery grown
plant from a tree fall collection made
by Daniel Metcalfe on 15 Apr 1994.
Flowers mostly white except for the
yellow and orange pattern on the
lip.”. Barcode SING0323376.
D.J. Metcalfe
s.n.
13 May
1994
BTNR
Flower in spirit. [presumably same
wild origin as H.T.W. Tan s.n.].
Barcode SING0323375.
Thurston s.n.
s.d.
Singapore (not
otherwise specified)
Not seen. Spirit specimen at Royal
Botanic Gardens, Kew, accession
7199.000.
H.N. Ridley s.n.
16 Jan
1892
Seletar
Barcode SING0010724.
H.N. Ridley
1702
22 Feb
1890
Tuas
Barcode SING0010723.
Bulbophyllum
gusdorfii
K.S. Chua et al.
NRS 1683
28 Apr
1993
Central Catchment
Nature Reserve,
Cluster 4, forest to the
north of MacRitchie
Reservoir near
Thompson Ridge.
Flowers in spirit. “Fl. in 7 Sep 1993,
1 Apr 1994, 27 Jun 1994”. Barcode
SING0323377.

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ACKNOWLEDGEMENTS
I thank the editor Louise Neo and an anonymous reviewer for their comments and improvements on the manuscript.
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