Feddes Repertorium 122 (2011), 1 – 7
Short Communication
Hoya mappigera (Apocynaceae, Asclepiadoideae),
a new campanulate flowered species from Peninsular Malaysia
and southern Thailand
MICHELE RODDA*, 1 & NADHANIELLE SIMONSSON JUHONEWE2
1
2
Herbarium, Singapore Botanic Gardens, 1 Cluny Road, Singapore 259569
P.O. Box 1–524, Ukarumpa, Eastern Highlands Province 444, Papua New Guinea
Keywords: Campanulate corolla, corona, Hoya campanulata, Hoya wallichii, Hoya wongii
*
Corresponding author: Senior Researche, Herbarium, Singapore Botanic Gardens, 1 Cluny Road,
Singapore 259569, E-mail: rodda.michele@gmail.com., Tel.: 00658281842
Accepted for publication: January 18th, 2012.
DOI 10.1002/fedr.201100019
Abstract
A new species, Hoya mappigera is described and
illustrated. Despite its oldest herbarium record being
more one century old it has been confused up to now
with either the co-occurring Hoya campanulata or
the Singapore endemic Hoya wallichii because of the
common presence of showy, broadly campanulate
corollas. A close examination of the corona morphology revealed that the closest morphological match is
neither of these species but instead the recently
described Brunei endemic Hoya wongii. The two
species can be easily separated because the latter has
bi-toothed inner corona lobes whereas the new species presents sulcate inner corona lobes ending in an
acuminate tip.
Introduction
Hoya R.BR species bearing campanulate corollas have been puzzling taxonomists ever since
the first species displaying this character was
described, Hoya campanulata BLUME. The
campanulate corolla has been an overlooked
character, and although in the past it brought
to the segregation of taxa in different genera
such as Physostelma WIGHT and Cystidianthus
HASSKARL, it concealed other characters helpful to separate campanulate Hoya species, such
as the shape of the corona. Only the recent
study of the coronas of type specimens allowed
to separate Hoya campanulata BLUME from
Hoya wallichii (WIGHT) C.M.BURTON, the first
presenting star shaped coronas, 3 – 4 mm high,
7 – 14 mm diameter with boat shaped narrow
lobes, the latter presenting erect kidney shaped
lobes, ca. 5 mm high, ca. 2 mm wide, basally
broadened into a swollen process with revolute
margins, apically forming a single acuminate
appendage ca. 1.2 mm long (RODDA & SIMONSSON submitted). This study also revealed
two new species, one endemic of Borneo,
Hoya danumensis RODDA & NYHUUS (2009),
the other endemic to Brunei, Hoya wongii
RODDA et al. (2011). The examination of
specimens from Peninsular Malaysia permitted
the separation of a further undescribed taxon
bearing similarities in coronal morphology
with H. wongii. We herein name the new
species as Hoya mappigera RODDA & SIMONSSON.
© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim 0014-8962
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The new species has been collected in five
localities in Peninsular Malaysia and one locality in southern Thailand.
Thailand is usually recognized high in Hoya
species and about 40 taxa have been reported as
occurring there (THAITHONG 2001). Peninsular
Malaysia instead presents 26 species and two
varieties (RINTZ 1978; KIEW 1989, 1995;
VELDKAMP & HANSEN 1996). The new species, described and illustrated below, is the first
campanulate flowered species for Thailand and
brings to 27 the number of Hoya species for
Peninsular Malaysia.
Hoya mappigera RODDA & SIMONSSON,
sp. nova
T y p e: Malaysia, State of Dingdings, Lumut
Dindings, 1894, RIDLEY s.n. (holotype SING,
barcode SING0120871).
Ad Hoyam wongii Rodda, SIMONSSON &
L. WANNTORP similis ob corollam campanulatam et coronam lobis inferius inflatis sed
differt coronae lobis superne erectis, cum acuminatis apicis.
Epiphytic or terrestrial glabrous climber.
Leafy stems cylindrical ca. 5 mm in diameter,
dark brown with conspicuous lenticels, adventitious roots absent. Internodes 8– 15 cm long.
Leaves opposite, petiolate; petiole channelled
along upper side, 7– 11 mm long, 1 –2 mm in
diameter; lamina dark green, lighter underneath, chartaceous when dry, stiff-coriaceous
when fresh, ovate-lanceolate, 7– 12 cm by 3 –
4 cm, apex apiculate-caudate, base attenuate,
colleters not observed, margin entire, main vein
depressed on adaxial surface, evident on abaxial surface, secondary veins 6 –9 each side,
branching at 60 –80° from main nerve. Inflorescences bearing a single open flower at a time,
lasting 1 – 2 days; peduncle extra-axillary, perennial, bearing scars of previous flowerings
3 – 6 cm long, ca. 1.5 mm in diameter; pedicels
green flushed pink on one side 1.5 – 3 cm long,
1 mm in diameter, glabrous. Calyx green ca.
5 mm in diameter, sepals elliptic to broadly
ovate 1.5 –2 mm × 1 – 1.5 mm, apex obtuse to
round, with 1 – 2 basal colleters between each
sepal ca. 0.35 × 0.3 mm glabrous with thinly
dentate margins. Buds 5-angular, light green,
© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Feddes Repert., Weinheim 122 (2011)
purplish only towards the pedicel. Corolla
campanulate, outside cream white, flushed pink
in proximity to the calyx lobes, inside cream
white with dull purplish centre and greenish
white around the edge and between the lobes,
4 – 5 cm in diameter overall glabrous with pubescence limited to the area beneath the corona;
corolla nearly entirely fused to a bowl-shaped
tube, 3.5 –4.5 mm in diameter, corolla lobes
triangular, ca. 5 mm long, acute, corolla with
intermediate lobules of nearly the size and
shape of the corolla lobes, but with a longitudinal fold. Corona staminal 6 –8 mm high, 6–
7 mm in diameter, lobes subdivided into two
distinct processes, a basal one, white, round,
free from the filament tube, with revolute lateral margins, the second connate with the filament tube, purple, sulcate and bent towards the
centre of the corona, ending in an acuminate
appendage, nearly touching in the centre, about
3 mm higher than tip of outer process and
0.7 mm higher than anther appendages; anther
skirt revolute, free from the filament tube.
Guide rail forming a vertical ridge, laterally
compressed, prominent at the base of the anther
skirt and extending 0.4 –0.7 mm laterally. Stigma head prominent, convex. Pollinarium (all
measures ca.) 1000 × 650 μm with two oblong
pollinia, 630 by 320 μm, apex and base rounded to obtuse, retinaculum 300 × 120 μm, caudicles broad, 180 × 80 μm. Ovary bi-carpellate,
bottle shaped, 2 mm long, each carpel ca. 1 mm
in basal diameter. Fruits and seeds not seen.
E ty m o lo g y: The specific epithet “mappigera” (mappa = napkin, -ger = to carry) refers
to the morphology of the corolla, white and
broad, resembling a napkin hanging from the
pedicel. Further, on herbarium specimens the
broad corolla folds around the corona like a
napkin, hiding the diagnostic characters for this
taxon.
Habitat & distribution: Hoya mappigera was collected in five localities in Peninsular
Malaysia and one locality in southern Thailand
(Fig. 3). So far recorded in lowland forests only
but appears to be adapted to a range of habitats
from swamp forest to the mixed dipterocarp
forest and kerangas-type vegetation usually
typical of thin sandy soils found in Klang Gates
ridge (KIEW 1982). Describing a new Hoya
species with showy campanulate flowers based
on six specimens is rather unusual since most
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M. Rodda & N. S. Juhonewe: Hoya mappigera sp. nov.
Fig. 1
Hoya mappigera sp. nova A, B — corona, side; C — corona, above; D — calyx; E — pollinarium;
F — corolla. (s. coll. AP1116, SING). Scale bar: A, B, C, D = 1 mm, E = 500 μm, F = 5 mm
© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
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Feddes Repert., Weinheim 122 (2011)
Fig. 2
Hoya mappigera sp. nova RIDLEY s.n. (holotype SING, barcode SING1020871)
© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
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M. Rodda & N. S. Juhonewe: Hoya mappigera sp. nov.
new taxa are described on single gatherings
(e.g. RODDA & SIMONSSON 2011, RODDA et al.
2011) whereas examples of species described
on the basis of multiple collections are limited
to endemic but locally abundant species such
as Hoya poilanei RODDA, SIMONSSON &
T.B.TRAN (RODDA et al. accepted) or widely
distributed species such as H. danumensis
(RODDA & NYHUUS 2009) or Hoya ignorata
T. B. TRAN, RODDA, SIMONSSON & JOONGKU
LEE (TRAN et al. 2011). Hoya mappigera appears to belong to the second case: it is a highly
adaptable species that despite being limited to
lowland conditions it occurs in different forest
types and therefore its potential distribution
area is most lowland forests in Peninsular Malaysia and southern Thailand.
IUCN Red List category: Population
size of H. mappigera cannot be estimated and
despite being known from six specimens, its
present distribution area cannot be evaluated
since only three specimens are less than
50 years old. Of the current known localities,
three have been most likely converted to plantations (RIDLEY s.n, SING; CURTIS s.n., SING;
KIEW RK1193, KEP), one, Klang Gates ridge
(SINCLAIR 10730, E) has been suffering from
the impact of human activities since the 1970s
5
(KIEW 1982) and despite being rich in endemic
species, is still threatened by human impact and
development (WONG et al. 2010). Recent investigation in the area failed to recollect the taxon
(RODDA, pers. obs.). The conservation status of
the Thai population and the northernmost Malaysian collections (CORNER S. F. 30338, SING;
s. coll. AP1116, SING) are not known. Further,
the species is most likely to be more widely
distributed than we now know from herbarium
records since it can be easily overlooked in the
field because it produces short-lasting single
flowers. Based on these observations the proposed conservation status is Near Threatened
(NT, IUCN, 2010) awaiting a re-evaluation
based on direct field observations.
Additional specimens examined (paratypes): Malay Peninsula, Flora of Kemaman,
Bukit Kayang, 500 ft. 8 Mar 1935, CORNER,
S. F. 30338 (SING0121241, SING); Ibid, Dindings, Bruas Rd. to Sungai Rotan, Feb. 1900.
CURTIS s.n. (SING0120875, SING); Ibid, 9th
mile Klang-Banting Road, 7 Jul 1982, KIEW
RK1193 (KEP160392, KEP); Ibid, Klang Gates
ridge (west) Selangor, Quarz ridge, 19 November 1962, SINCLAIR 10730 (E00312531, E);
Thailand, southern Thailand, Betong, Yala
province, cultivated in Thailand, Bangkok,
Fig. 3
Distribution of Hoya mappigera in peninsular Malaysia and Thailand based on the examined specimens
(indicated by a full circle). Peninsular Malaysia is indicated in light grey colour. Map constructed using
SimpleMappr (www.simplemappr.net)
© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
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Feddes Repert., Weinheim 122 (2011)
Table 1
Morphological comparison between Hoya mappigera and other campanulate Hoya species
H. mappigera
H. wongii
H. campanulata H. wallichii
H. danumensis
Corona
diameter
6 – 7 mm
ca. 6 mm
7 – 14 mm
6 – 7 mm
10 – 14
Corona lobe
subdivided in
subdivided in
boat shaped
basal and apical basal and apical
process
process
erect, kidney
shaped
oblong ovoid
Corona colour
basal process
white, apical
process purple
pale yellow
white
purple
white
Corona outer
lobe shape
round
round
acute
round
round
Corona inner
lobe shape
sulcate with an
acuminate tip
ending in two
acute
bi toothed
membranaceous
appendages
acuminate
acute
Number of
flowers for
inflorescence
1
1
1
ca. 20
Aug. 2011, s. coll. AP1116 (SING0165301,
SING).
ca. 20
stiff apical process (Fig. 1A, B, C). A comparison between H. mappigera, H. wongii and other
species bearing a campanulate corolla is presented in Table 1.
Discussion
Acknowledgements
The process of species discovery may be delayed by decades if not even centuries since the
collection of specimens (BEBBER et al. 2010).
In the case of H. mappigera, the misapplication
of the names H. campanulata and H. wallichii
to most Hoya specimens bearing a campanulate
corolla has been the cause of the delay in its
classification. The first specimen of this taxon
was in fact collected 118 years ago, in 1894
(RIDLEY s.n., SING).
The closest morphological match of
H. mappigera is surprisingly neither the cooccurring H. campanulata nor H. wallichii,
endemic of the island of Singapore (RODDA &
SIMONSSON submitted) but instead the Brunei
endemic H. wongii. The two species present a
similar broad corolla and their corona lobes are
similarly subdivided in a basal round process
and an erect apical process. They can be easily
separated because the apical coronal process in
H. wongii is subdivided in two bidentate membranaceous appendages while in H. mappigera
it is entire, sulcate and bears a single acuminate
© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
This study is part of an ongoing research project on
the systematics of Hoya. Financial support has been
received from the National Parks Board Singapore
and the Synthesys programme, grants no GB-TAF5657, NL-TAF-676 and DETAF-675 for Rodda and
from Helge Ax:son Johnsons Stiftelse for Simonsson
Juhonewe. We would like to thank the curators of
the following herbaria: A, B, BM, BRUN, E, FI,
HBG, K, L, P, SAN, SING, SNP and TO for help
with material and for providing high quality images
of herbarium specimens, JF Veldkamp for his advice
on Latin etymology, Graham Hardy for providing
field notes of J. Sinclair conserved in RBGE library,
Rapeepattadha Chamwong and Sutthisak Sangkhakorn for supplying information on the Thai collection (s. coll. AP1116, SING), and two anonymous
reviewers for their valuable comments on the manuscript.
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