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Taxonomy, ecology, and conservation status of Philippine Rafflesia (Rafflesiaceae)



The number of Rafflesia species (Rafflesiaceae) reported for the Philippines has grown explosively from two before 2002 to ten or eleven presently. We present an overview of the current knowledge of Philippine Rafflesia by providing a comprehensive account of all the recognized species with their taxonomy, distribution and ecology, plus a key and photographs to aid in identification. Their conservation status and that of the rain forest habitats they require is discussed.
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Blumea 54, 2009: 77– 93 doi:10.3767/000651909X474122
Rafflesia R.Br. (Rafflesiaceae) is a genus of parasitic plants
growing in the forested lowlands and low to mid-elevation
montane forests of Thailand, Peninsular Malaysia, Sumatra,
Java, Borneo and the Philippines. The plants entirely lack
leaves, chlorophyll, separate stems, and roots, and are there-
fore completely dependent on their host plants for water and
nutrients. The hosts of Rafflesia are species of the liana genus
Tetrastigma Planch. (Vitaceae; Plate 1). The parasitic plants
live inside the roots and stems of their host and only their
flowers emerge. The flowers of some Rafflesia are the largest
of all flowering plants, reaching up to 1.5 m diam in R. arnoldi
R.Br. (Nais 2001). Although the flowers are typically unisexual,
occasionally bisexual flowers are formed (e.g., R. baletei Bar-
celona & Cajano). Carrion flies (e.g., Calliphora, Chrysomya,
Lucilla, Sarcophaga; Plate 3e; Beaman et al. 1988, Bänzinger
1991, Nais 2001) seem to be the main pollinators of Rafflesia
and, at least in some species (notably R. schadenbergiana and
R. speciosa), the flies are attracted by the fetid smell emitted
by the flower (Bänzinger 1991). However, hardly any additional
details are known about the reproductive biology of Rafflesia.
For example, although small mammals have been mentioned as
possible dispersal agents (Meijer 1985, Anonymous 1992, Nais
2001), the precise dispersal mechanisms of Rafflesia seeds are
all speculative. Furthermore, the host infection process is yet
another of Rafflesia’s mysteries.
Recent molecular phylogenetic studies have shown that Raf-
flesia and the other two genera in Rafflesiaceae (Rhizanthes
Dumort. and Sapria Griff.) form a well-supported clade nested
within Euphorbiaceae s.l. (Davis et al. 2007). This finding
may seem surprising at first, because obvious morphological
synapomorphies with Euphorbiaceae are wanting, but it is, in
retrospect, not completely unexpected considering Rafflesias
highly specialized life form and the incredible morphological
diversity of Euphorbiaceae s.l. Despite the current strong
interest in the evolutionary history of Rafflesia, species-level
phylogenetic relationships are currently unknown.
Until recently, the centre of species diversity of Rafflesia was
thought to be the islands of Borneo and Sumatra. Out of the 18
recognized species described before 2002, eight were found
in Borneo and seven in Sumatra, whereas only one species
was reported from Thailand, three from Peninsular Malaysia,
two from Java and two from the Philippines (R. manillana
Teschem. and R. schadenbergiana Göpp.). The description
of R. speciosa from Panay Island in the Philippines in 2002,
however, marked the start of a period of enormous increase in
the knowledge of Philippine Rafflesia. Including R. speciosa,
six new Rafflesia species endemic to the Philippines have been
described since 2002 (Plate 2, 3). Additional findings include
a species from north-eastern Luzon that closely resembles
R. tengku-adlinii from Borneo (described separately in Barce-
lona et al. in press; Plate 3b) and another small-sized Rafflesia
from Mt Matutum in Mindanao (Barcelona et al. 2006, 2007).
Unfortunately, the only specimen preserved of the latter species
is too deteriorated to determine its taxonomic identity, but it may
very well be a new species. These new discoveries therefore
bring the total number of species in the archipelago to ten or
eleven (Map 1). In the same period, only two new Rafflesia
species were described from outside the Philippines: R. azlanii
Latiff & M.Wong (2003) from Peninsular Malaysia and R. beng-
kuluensis Susatya, Arianto & Mat-Salleh (2005) from Sumatra.
New Rafflesia discoveries since 2002 have brought the total
number of currently recognized and described species to 27 and
indicate that the Philippines contains ten or eleven species of
Rafflesia, at least two more than is found on either Borneo and
Sumatra. The Philippines thus has the highest species richness
of known Rafflesia of any major geographic entity.
The renewed interest in Philippine Rafflesia that was spurred by
the discovery of R. speciosa (Barcelona & Fernando 2002) has
not only provided a better estimate of the number of species in
the genus, but also resulted in an increase in our knowledge of
the only two Rafflesia species known to the archipelago before
Taxonomy, ecology, and conservation status of Philippine
Rafflesia (Rafflesiaceae)
J.F. Barcelona1, P.B. Pelser2, D.S. Balete3,4, L.L. Co 3,5
1 Philippine National Herbarium, Botany Division, National Museum of the
Philippines, P. Burgos St., P.O. Box 2659, Manila, The Philippines.
2 University of Canterbury, School of Biological Sciences, Private Bag 4800,
Christchurch, New Zealand.
3 Institute of Biology, College of Science, University of the Philippines, Dili-
man, Quezon City 1101, The Philippines.
4 Field Museum of Natural History, Department of Zoology, 1400 South Lake
Shore Drive, Chicago IL 60605, USA.
5 Conservation International-Philippines, 6 Maalalahanin St., Teacher’s Vil-
lage, Diliman, Quezon City 1101, The Philippines.
Key words
Abstract The number of Rafflesia species (Rafflesiaceae) reported for the Philippines has grown explosively
from two before 2002 to ten or eleven presently. We present an overview of the current knowledge of Philippine
Rafflesia by providing a comprehensive account of all the recognized species with their taxonomy, distribution and
ecology, plus a key and photographs to aid in identification. Their conservation status and that of the rain forest
habitats they require is discussed.
Published on 30 October 2009
78 Blumea – Volume 54, 2009
R. speciosa
15 307.5 cm
R. lobata
R. baletei
R. manillana
R. leonardi
Rafflesia sp.
R. philippensis
R. mira
R. schadenbergiana
Map 1 Locations of known Rafflesia populations in the Philippines. Red: active populations verified with collections or photographs; yellow: historic popula-
tions; white: populations of a small flowered Rafflesia from Mt Matutum on Mindanao. Photographs of Rafflesia flowers are presented scaled according to their
relative sizes. All photographs by the authors, except those of R. baletei (M.O. Cajano), R. lobata (R.L. Martin Jr.), R. manillana (A. Diesmos), and R. mira
(Department of Tourism, Compostela Valley).
J.F. Barcelona et al.: Philippine Rafesia
R. speciosa was described. New populations of R. manillana
were found in Luzon (Plate 2c, d, 3e g, 4a, b), giving a more
accurate view of the distributional range of this species (Map
1). For the first time in 110 years, active (i.e., flower producing)
populations of R. schadenbergiana have been seen in Minda-
nao (Lays 2006, Barcelona et al. 2007, 2008a, Plate 2g, 3l– n),
a species feared to have gone extinct (Barcelona et al. 2006).
Furthermore, the discovery of new Rafflesia populations con-
tributed to a better understanding of infraspecific morphological
diversity and ecological preferences of Philippine Rafflesia
(Plate 2, 4). Many of these newly found populations are remote
from other populations of the same species and are found
outside of protected areas. In addition, they consist of very few
individuals and are highly threatened by logging, slash-and-burn
agriculture (Plate 4d, f) and disturbance by curiosity-seekers
and unsustainable ecotourism (Plate 4g, h). The recent interest
in Rafflesia in the Philippines has therefore also emphasized
the urgent need for effective local conservation strategies to
protect these plants from extinction. In this paper, we summarize
the current knowledge of Philippine Rafflesia.
1. Fully expanded flower less than 40 cm diam .........2
1. Fully expanded flower more than 40 cm diam .........7
2. Diaphragm aperture narrow, less than 1/2 of the diaphragm
diam, as wide as or narrower than the diam of the disk, not or
only partially exposing inner surface of the perigone tube 3
2. Diaphragm aperture wide, more than 1/2 of the diaphragm
diam, wider than the diam of the disk, fully exposing the inner
surface of the perigone tube . . . . . . . . . . . . . . . . . . . . . . 5
3. Flowers orange throughout, without whitish warts; ramenta
usually more than 5 mm long. — Luzon . . . . Rafflesia sp.
3. Flowers orange, dark- or rusty-brown, dark reddish or ma-
roon, perigone with prominent whitish warts; ramenta less
than 5 mm long ................................4
4. Disk creamy white centrally, becoming reddish brown towards
the periphery, undersurface (corona) whitish, tan peripheral-
ly; processes monomorphic, in two concentric rings; ramenta
nearly uniformly distributed from the base of the perigone
tube to the diaphragm; diaphragm aperture round, except in
flowers disfigured during development; windows (white blots
on the lower surface of the diaphragm) absent; flowers often
bisexual. Luzon....................... R. baletei
4. Disk pale yellow or yellowish cream centrally, maroon to-
wards the periphery, undersurface uniformly maroon; proc-
esses polymorphic, variously disposed; ramenta polymor-
phic, scattered, more or less solitary and less-branched in
the perigone tube, clustered, larger, stouter and dense inside
the diaphragm; diaphragm aperture usually oval; windows
present in larger flowers; flowers strictly unisexual. Luzon
.................................. R. philippensis
5. Fully expanded flower 25 cm or more in diam; disk 7–8 cm
diam, nearly smooth or with poorly developed processes;
windows absent. — Luzon . . . . . . . . . . . . . . . . R. leonardi
5. Fully expanded flower less than 25 cm diam; disk up to 5 cm
diam, processes well developed; windows present . . . . 6
6. Diaphragm lobed, almost snow white in newly opened flow-
ers. Panay............................ R. lobata
6. Diaphragm usually entire, cream coloured with round or
elliptic blots that are sometimes coalescent. — Luzon and
Samar .............................. R. manillana
7. Disk processes polymorphic, larger ones laminar or plate-
like, erose, radially disposed; perigone warts round or elliptic,
rim of aperture darker than diaphragm. — Mindanao . . . .
........................................ R. mira
7. Disk processes monomorphic, conical, arranged in concen-
tric rings; perigone warts elongated, rim of aperture whitish
or paler than the diaphragm . . . . . . . . . . . . . . . . . . . . . . 8
8. Newly opened flowers 52 80 cm diam, reddish maroon;
diaphragm rugose, larger perigone warts 1 cm or more wide,
sometimes coalescent or reticulate, processes more than
40. Mindanao.................R. schadenbergiana
8. Newly opened flowers 45–56 cm diam, rusty- or reddish
brown; diaphragm generally smooth, larger perigone warts
less than 5 mm wide, free; disk processes less than 40.
— Panay and Negros. . . . . . . . . . . . . . . . . . . . R. speciosa
Rafflesia baletei Barcelona & Cajano — Plate 2a, 3a, 4e
Rafflesia baletei Barcelona & Cajano in Barcelona et al. (2006) 232.Type:
Candelaria et al. 5526 (holo PNH; iso CAHUP, K, SING, US).
Diagnostic characters — Rafflesia baletei flowers are (9–)
15–16(– 22) cm diam and the smallest in the genus. Depend-
ing on age, the perigone lobes are orange or dark, reddish- or
rusty-brown. They are erect basally, but recurved apically
with one lobe usually noticeably smaller than the rest. The
perigone warts are prominently raised and variously shaped.
These leave reticulate impressions on the diaphragm that are
sharp-edged and irregular in shape, although commonly form-
ing pentagonal areoles. The diaphragm aperture is 3 3.5 cm
diam and has a reddish brown rim, which is darker than the rest
of the diaphragm. The disk is 5 5.5 cm diam, dome-shaped,
and glistening creamy white centrally to reddish brown at the
periphery. The processes are unbranched (sometimes with
small projections), conical, up to 1 cm long, and arranged in
2 concentric rings. The ramenta are dense, nearly uniformly
distributed on the inside of the perigone tube and diaphragm,
branched, up to 2 mm long, and longest at the base of the
perigone tube. Windows are absent. The floor of the perigone
tube is velutinous. Male flowers have vestigial ovaries and
contain 11–14 semi-globose anthers.
Taxonomic notes — Misidentification of an earlier collection
of R. baletei composed of two dried flowers collected in 1991
(Balete & Peñas s.n., CAHUP) was responsible for previous re-
ports of R. manillana from Mt Isarog (Heaney & Regalado 1998,
Nais 2001, Fernando et al. 2004, Fernando & Ong 2005).
Distribution — Luzon, Camarines Sur, Mt Isarog and Mt Asog
(= Mt Iriga).
Ecology & Conservation — Rafflesia baletei occurs in rocky,
riparian habitats (Plate 4e), usually in steep and well-drained
secondary forests planted with Musa textilis Née and bamboos
at 500–560 m. Peak flowering months are December to May.
Although some Rafflesia populations are located in Mt Isarog
National Park, a protected area, they are found in areas that
are prone to erosion during the typhoon season. In fact, a ty-
phoon in 2006 destroyed much of the Rafflesia population on
Mt Isarog when the host vines were brought down by falling
trees (M.O. Cajano, University of the Philippines, Los Baños,
pers. comm.).
Rafflesia leonardi Barcelona & Pelser — Plate 1f, h, 2f, 3i, 4c
Rafflesia leonardi Barcelona & Pelser in Barcelona et al. (2008a) 224. — Type:
Barcelona et al. 3355 (holo PNH; iso L, PUH, US).
Diagnostic characters — Fully expanded flowers of R. leon-
ardi range 25.5–34 cm diam and are reddish orange in new
blooms. The perigone lobes are 5, seldom 6, and have tan to
pale yellow margins. The powdery white warts on the perigone
lobes are prominent, free, mostly round or elliptic. The larger
ones are interspersed with tiny ones. The diaphragm is usually
80 Blumea – Volume 54, 2009
Plate 1 Tetrastigma (Vitaceae) species found as hosts of Rafflesia. a, b. Tetrastigma pisicarpum, host of R. philippensis on Mt Banahaw: a. leaves, b. above-
ground roots with emerging Rafflesia buds; c. Tetrastigma papillosum, host of R. schadenbergiana on Mt Kitanglad; d. Tetrastigma sp., host of R. manillana on
Mt Natib; e. Tetrastigma sp., host of R. speciosa in Sibalom Natural Park; f– h. Tetrastigma cf. loheri, host of both R. manillana (in Bolos Point and Kanapawan,
and possibly on Mt Labo) and R. leonardi (in Kanapawan): f. trifoliate leaves, g. prostrate vine with scars of R. manillana flowers, h. host plant of R. leonardi.
— Photos by J.F. Barcelona.
g h
e f
J.F. Barcelona et al.: Philippine Rafesia
Plate 2 Philippine Rafflesia flowers in situ, showing their relative sizes. a. R. baletei, Mt Isarog; b. R. lobata, Mt Agua Coloña; c. R. manillana, Mt Labo; d. R. manil-
lana, Kanapawan; e. R. philippensis, Mt Banahaw; f. R. leonardi, Kanapawan; g. R. schadenbergiana, Baungon; h. R. speciosa, Valderrama. — Photos by:
a, e: M.O. Cajano, b: R.L. Martin Jr., c, d, f– h: J.F. Barcelona.
e f
82 Blumea – Volume 54, 2009
14–18 cm diam, but can reach 22 cm in large specimens.
The outer surface of the diaphragm bears shallow perigone
wart impressions surrounded by slightly raised ridges that are
decorated with tiny tan coloured speckles. Windows are ab-
sent. The wide diaphragm aperture, 10.5–12.5(–19) cm diam,
is reminiscent of R. manillana and R. lobata. The rim of the
diaphragm is maroon and concolorous or slightly darker than
the surrounding tissue. The disk is 7– 8 cm diam, almost flat
to slightly dome-shaped with a slightly raised margin. It is tan
centrally, purplish maroon towards the periphery, and nearly
smooth or with up to 10 poorly developed processes. When
present, the processes are tuberculate or sometimes conical
and pointed, up to 5 mm or occasionally somewhat longer,
and dark maroon. The ramenta are short, up to 2 mm long,
dimorphic, those toward the base of the perigone tube dense
and filiform, those on the lower surface of the diaphragm more
sparse and clustered, stout, branched or cleaved apically, and
with dark tips. Male flowers are without vestigial ovaries and
have 20 or 21 anthers, which are deeply immersed in the anther
sulci. The female flowers are as big as the male flowers and
are without vestigial anthers. The ovary is c. 1.2 by 6 cm and
lunate in longitudinal section.
Taxonomic notes — The correct spelling of the specific epi-
thet is leonardi but due to a misprint in the original description, it
appeared in that one place as leonardii (Barcelona et al. 2008a:
224, line 1).
Distribution — Luzon, Cagayan Province, Gattaran & Lallo
Municipalities, Barangays Bolos Point and Kanapawan.
Ecology & Conservation — Rafflesia leonardi is found in
logged-over lowland dipterocarp forests at 270 300 m. This
is, thus far, the lowest elevation confirmed for Rafflesia popula-
tions in the Philippines, although R. manillana was reported to
occur at c. 120 m on Mt Makiling (E.S. Fernando, University
of the Philippines, Los Baños, pers. comm.). The plants grow
along river and stream banks on thin soil and rocky substrates
(Plate 2f, 4c). Tetrastigma cf. loheri Gagnep. was identified as
the host plant (Plate 1f). Rafflesia leonardi forms flowers on
both the exposed roots and the climbing parts of its host (Plate
1h), occasionally up to a height of c. 10 m above ground level.
A total of six populations were found in the region, which is not
currently part of a protected area. One population was sympatric
with R. manillana.
Rafflesia lobata R. Galang & Madulid — Plate 2b, 3c, 4f
Rafflesia lobata R. Galang & Madulid (2006) 2, Pl. 1–10. — Type: Galang
et al. 001 (holo PNH).
Diagnostic characters — This species is similar to R. manil-
lana in flower size (11–21 cm diam) and gross morphology. It
has a wide-open diaphragm aperture fully exposing the inner
surface of the perigone tube. The diaphragm is lobed, the
lobes are initially incurved, their outer surface nearly smooth,
uniformly snow-coloured without warts or speckles during
early anthesis becoming outcurved and pale brown with age;
windows are present on the inner surface. The annulus is well-
developed. The disk processes are stout and sometimes poorly
developed, having tips with fine black hairs.
Distribution — Panay. Rafflesia lobata was originally de-
scribed from populations discovered in 2005 on Mt Igtuog and
Mt Sakpaw in Sebaste and Pandan municipalities, Antique
Province, in the north-western part of Panay Island (Galang &
Madulid 2006). The presence of a population of R. lobata on Mt
Agua Coloña, part of the mountains bordering the municipality of
Leon, Iloilo Province and Antique Province on Panay Island was
brought to our attention by members of The Antique Outdoors
(TAO), an environmental advocacy group. The same group
also led us to a third population of R. lobata in the municipality
of San Remegio, Antique Province in May 2008. The recent
discovery of these populations in the southern part of the island
indicates that R. lobata may very well be more widespread in
Panay than previously thought.
Ecology & Conservation — Rafflesia lobata grows at 400
950 m and is mostly found in gullies in primary or severely
degraded lowland rain forest or limestone forest (Plate 4f). Just
like R. manillana, the flowers of this species emerge both on
the roots and climbing shoots of its host. It flowers throughout
the year, but predominantly from February to June. Galang
& Madulid (2006) mention seven populations of R. lobata in
Sebaste and Pandan (Antique). Neither of these nor the popu-
lations in Leon (Iloilo) and San Remegio (Antique) is located
in a protected area.
Rafflesia manillana Teschem. — Plate 1d, f, g, 2c, d, 3e h,
4a, b
Rafflesia manillana Teschem. (1842) 63, t. 6. — Rafflesia cumingii R. Br.
(1844) 243, nom superfl. — Type: Navarro s.n.? (A n.v., lost?).
Rafflesia lagascae Blanco (1845) 595. — Type: Azaola s.n. (not preserved).
Rafflesia panchoana Madulid, Buot & Agoo (2008, ‘2007’) 43. — Type: W.H.
Brown s.n. (Species Blancoanae 535) (holo US904212, erroneously cited
in the protologue as US0090412).
Local name — Malabo-o (Tagalog).
Diagnostic characters — Fully expanded flowers of R. manil-
lana range from 11–24 cm diam. The perigone lobes are red-
dish to rusty brown and ornamented with whitish warts. The
diaphragm is more or less erect, sometimes slightly incurved
and has an entire rim which shows a narrow whitish band
surrounded by a broader, more conspicuous reddish maroon
band. The aperture is wide open and exposes the inner struc-
tures of the flower including diaphragm windows, and similar
smaller white blots on the interior surface of the perigone tube,
as well as the disk with processes that are stout, pustular to
sometimes rudimentary and tipped with dark brown to blackish
hairs. The annuli of male flowers have very clear impressions
of the anthers and these are lined by minute tubercles and
club-shaped bodies intermixed with fine bristles. The sex of
a flower and the number of anthers (ranging from 10–18) in
male flowers can therefore easily be determined in R. manillana
without dissection.
Taxonomic notes — The type of R. manillana was composed
of three immature buds sent to Teschemacher (most probably
by Father Pedro Navarro, a Franciscan naturalist; Blanco 1845:
566) from Basei (= Basey) in Samar Province in 1841. The
protologue stated that Basey is located in Leite (= Leyte), but
although Samar was indeed governed as part of Leyte Province
from 1735 to 1768 (Philippines Census Office 1920: 246), both
islands were already separate provinces in Teschemacher’s
time and Leyte was therefore mistakenly named as the island
of the type of R. manillana. No additional collections of Rafflesia
were made in Samar or Leyte until R. manillana was rediscov-
ered in Basey in 2007 (Madulid & Agoo 2008). Since the type
of R. manillana is apparently lost, this recent discovery allowed
botanists, for the first time in 166 years, to compare the morphol-
ogy of plants collected near the type locality with those found in
Luzon. On the basis of this comparison, Madulid et al. (2008)
concluded that the rediscovered R. manillana from Samar is a
different species from the Luzon populations and consequently,
they renamed the Mt Makiling populations previously assigned
to R. manillana as R. panchoana. Among the characters used
to differentiate R. manillana from R. panchoana is the presence
of “tuberculous structures at the columnar base and annular
rim …” in flowers of R. manillana that are, accordingly, replaced
by bristles in R. panchoana. Although Madulid & Agoo (2008:
65, Pl. 1g) include a photograph of a close-up from a wilted
flower to illustrate these structures, we also observed similar
J.F. Barcelona et al.: Philippine Rafesia
minute (< 0.5 mm) tubercles mixed with bristle-like structures
in flowers of R. manillana from Bolos Point, Luzon (Plate 3g, h).
In addition to the presence of these tubercles, the authors
indicate a difference in anther number between the Samar
and Luzon populations (10 –12 in R. manillana and 14 –18 in
R. panchoana). Anther numbers have, however, only been
established for relatively few specimens in both the Samar and
Luzon populations. Furthermore, the lower anther number of
the Samar population coincides with a flower size that is in the
lower range of what is found in the Luzon populations. Anther
counts of additional flowers from both islands may eliminate
the gap in anther numbers between the Samar and Luzon
populations. Other distinguishing characters mentioned by
Madulid & Agoo (2008) are the morphology of the warts of the
perigone lobes, the windows, the ramenta, and the shape of
the diaphragm. Our own studies of the morphological diversity
in the various Luzon populations, however, showed that these
characters are quite variable and overlap with the variation
reported for the Samar population. The incurved diaphragm
mentioned as diagnostic for the Samar population, for instance,
has also been observed in flowers from Mt Makiling in Luzon
(see Brown 1912, plate 12, fig. 1 & 2). Because of these very
dubious morphological differences between the Luzon and
Samar populations and pending examination of plants of the
Samar population, we, for now, consider the Luzon populations
traditionally assigned to R. manillana as indeed conspecific
with R. manillana Teschem. from Samar. Thus R. panchoana
is therefore reduced to synonymy here.
The name R. panchoana would, however, still also be a syno-
nym if the Luzon and Samar R. manillana populations are
shown to be separate species, because an older name is
available for this taxon. Rafflesia lagascae was published in
the second edition of the Flora de Filipinas (Blanco 1845) and
we follow Merrill (1918, 1923) in recognizing this name as an
earlier synonym for the Luzon populations of R. manillana. Both
R. lagascae and R. philippensis (another Rafflesia species
published in Blanco’s Flora) were described from Monte de
Majaijai (= Mt Banahaw; Global Volcanism Program website,
Smithsonian Institution) that were collected by Iñigo Gonzales
y Azaola. Unfortunately, these specimens were not preserved
and Rafflesia was not encountered on Mt Banahaw since Azaola
until recently on this mountain (Madulid et al. 2007, Barcelona et
al. 2007). Although Merrill considered both names synonyms of
R. manillana (1918, 1923), only the description of R. lagascae
matches R. manillana, which occurs on nearby Mt Makiling, and
may have recently again been found on Mt Banahaw (E.S. Fer-
nando, University of the Philippines, Los Baños, pers. comm.).
Blanco’s posthumously published notes of the specimens of
R. lagascae described to him by Azaola, for instance, mention
the reddish maroon band at the rim of the diaphragm aperture
characteristic of R. manillana from Luzon: “…a exception de la
línea circular de caliz que es de color pardo rojizo…” (p. 595).
Moreover, Blanco’s text refers to the black silky hairs of the
processes, which are only found in R. manillana and R. lobata:
“Del centro de dicho caliz se eleva una columna truncada … y
en su superficie se ven varios puntos, salientes de color negro,
dotados de sedas negras con lámina sin pistilo” (p. 595). Only
the size of the open flower of R. lagascae deviates from what
is found in R. manillana, being much larger (c. 1 foot), but this
is likely a very rough size estimate. In addition to the morpho-
logical characters mentioned in the description of R. lagascae
and its proximity to areas where R. manillana have been found,
the elevation that Azaola recorded for this species suggests
that both names apply to the same species. The protologue of
R. lagascae indicates that it was found between c. 1 085–1 117 m
(“… a la altura de seiscientas sincuenta á setescientas brazas
sobre el nivel del mar …”, Blanco 1845: 595) and this elevation
is close to the highest elevation recorded for R. manillana on
Mt Makiling (c. 1 000 m) (M.O. Cajano, University of the Philip-
pines, Los Baños, pers. comm).
Rafflesia cumingii is a name based on the type of R. manillana
and therefore superfluous. Brown rejected the latter name as he
found it inappropriate. The rest of Brown’s paper (Brown 1844),
however, was based on Cuming s.n., which probably prompted
Meijer to state that “the type of R. cumingii is a Cuming collection
at BM, most likely from the same site as the Navarro collection
seen by Teschemacher” (Meijer 1997: 27).
Distribution — Luzon and Samar. Until recently, in the ab-
sence of finding R. manillana populations at the historical col-
lection sites in Kalinga in northern Luzon (Merrill 1923), Samar
(Teschemacher 1842, Meijer 1997, Nais 2001), or elsewhere in
the Philippines, the only known active population of R. manil-
lana was located on Mt Makiling in Laguna Province in Luzon.
It is only since 2005 that additional populations of R. manil-
lana have been found, thus expanding our knowledge of the
geographical range of this species. These findings indicate a
distributional area in Luzon stretching from Mt Labo in Cama-
rines Norte (Barcelona et al. 2006) in south-eastern Luzon to
Mt Natib in Bataan Province (Barcelona et al. 2006) in the west
and Barangay Bolos Point, Gattaran and Barangay Kanapa-
wan, Lallo Municipalities, Cagayan Province in the northern
part of the island (Barcelona et al. 2008a). In addition to these
localities and Mt Makiling, photographic evidence indicates
that R. manillana is also found on Mt Kayapo in General Nakar,
Quezon Province (N. Bartolome, Conservation International-
Philippines, pers. comm.), and very recently, on Mt Irid, Rodri-
guez (= Montalban), Rizal Province (pers. obs. by DSB). The
present geographical range of R. manillana, therefore, seems
to consist of Basey in Samar and the majority of Luzon (Map 1).
A Rafflesia specimen collected in 1991 on Mt Isarog in Cama-
rines Sur (Balete & Peñas s.n., CAHUP) and thought to be
R. manillana (Heaney & Regalado 1998, Madulid 2000, Nais
2001, Barcelona & Fernando 2002, Fernando et al. 2004, Fer-
nando & Ong 2005) proved to be a different species, R. baletei
(Barcelona et al. 2006).
Ecology & Conservation — Rafflesia manillana is found in
openings in dipterocarp forests up to 1 200 m, although it is
more common at lower elevations (as low as 120 m). It most
frequently grows in forest gaps or margins, and along river- and
stream-banks or trails (Plate 4a). The flowers emerge both on
the roots and climbing shoots of their host (Plate 1g, 2c, d).
In Bolos Point (Cagayan Province), the host Tetrastigma is
found in karst limestone forest (Plate 4b), the first record of
this habitat type with a Philippine Rafflesia. The host species
identified for the population of R. manillana at Bolos Point,
Tetrastigma cf. loheri, is morphologically similar to the host
of the population on Mt Labo, R. mira of Compostella Valley
(Fernando & Ong 2005), and R. leonardi which grows sym-
patrically with R. manillana in Kanapawan (Plate 1f, g). One
population of R. manillana in Kanapawan is peculiar in that
all the flowers have lobed diaphragms (Plate 3g). Although
irregular in number, shape and size, the diaphragm lobes in
this population resemble those observed in R. lobata of Panay
(Plate 3c). The diaphragm lobes of R. lobata, however, are
more pronounced. Since the majority of the populations of
R. manillana in Cagayan Province possess the typical entire
diaphragm, until further study, we consider the lobed diaphragm
in this species as a morphologically deviant variant without
taxonomic significance.
Despite being the most common and having the largest range
of all known Philippine Rafflesia species, R. manillana has a
patchy distribution with relatively small populations in widely
separated forest fragments. Except for those on Mt Makiling
and Mt Natib, all other known populations of this species are
84 Blumea – Volume 54, 2009
e f
Plate 3 a– l. Philippine Rafflesia species. a. R. baletei, Mt Isarog; b. Rafflesia sp., Sierra Madre Mountains; c. R. lobata, Mt Agua Coloña; d. R. philippensis,
Mt Banahaw; e. R. manillana, Mt Labo; f. R. manillana, Mt Natib; g, h. R. manillana, Kanapawan; i. R. leonardi, Kanapawan; j. R. speciosa, Valderrama;
k. R. mira, Mt Candalaga; l– n. R. schadenbergiana, Baungon; o, p. Rafflesia as symbol for nature conservation, Buruyluganay Festival, Panay. Antique Prov.,
Sibalom. — Photos by: a: M.O. Cajano, b: D.S. Balete, c: R.L. Martin Jr., d– f, i, j, l–p: J.F. Barcelona, g, h: B. van Ee, k: Department of Tourism, Compostela
Valley Province, Region XI, Mindanao.
J.F. Barcelona et al.: Philippine Rafesia
Plate 3 (cont.)
m n
86 Blumea – Volume 54, 2009
Characters R. baletei R. lobata R. manillana R. philippensis R. leonardi R. speciosa R. mira R. schadenbergiana
Position of flowers on host on roots on roots and on roots and on roots on roots and on roots and on roots on roots
climbing shoots climbing shoots climbing shoots climbing shoots
Flower diameter (cm) 9– 22 11–21 11–24 17.5–27(– 32) 25.5– 34 45– 56 45– 60 52– 80
Perigone colour orange reddish orange reddish orange red, less often reddish orange reddish orange reddish orange reddish orange to
reddish orange to red to red maroon
Perigone wart / ornamentation shape round or elliptic round or elliptic round or elliptic elliptic or slightly round or elliptic elongated mostly round elongated to reticulate
elongated or elliptic
Diaphragm rim entire lobed entire entire entire entire entire entire
Diaphragm rim colour vs diaphragm colour darker concolorous white white concolorous concolorous or white red white
Diaphragm surface reticulate smooth smooth rugose smooth smooth smooth rugose
Ratio diaphragm / aperture diameter 2.3–2.5 up to 1 1.33(–1.8) 2 –2.2 1.2 –1.5 1.8 –2(– 2.4) c. 2 1.8 –2.2
Diaphragm aperture shape round round round oval round round round round
Disk processes number 19– 26 7–14 14– 30 up to c. 25 absent or up to 10 17–31 38 –40 30– 63
Disk processes arrangement / disposition regular concentric irregular concentric irregular concentric irregular, not in rings irregular concentric regular concentric irregular concentric regular concentric rings
rings rings rings rings rings rings
Disk processes maximum length (cm) 1 0.5 0.55 1.5 0.5 2.3 1 3
Disk processes types monomophic, conical monomophic, conical monomophic, conical dimorphic, prominent- almost absent, when monomorphic, polymorphic in 4 monomorphic, conical,
or slightly laterally or slightly laterally or slightly laterally ly flattened laterally present monomorphic, conical, often zones: conical often unbranched
compressed, compressed, compressed, and branched, inter- poorly developed, unbranched central ones followed
often branched unbranched unbranched spersed with tuber- conical, unbranched by blades perpedicular
culate ones to each other, then
outermost ones reduced
Ramenta colour relative to surrounding tissue darker white white darker darker darker darker darker
Ramenta length (mm) up to 2 1–2 0.5 –1 up to 5 up to 2 up to 2 5 –10 4 –10
Ramenta distribution on the perigone uniform sparse at base sparse at base sparse at base abundant at base, uniform sparse at base, sparse at base, abun-
tube and diaphram abundant towards abundant towards abruptly more gradually more abundant halfway, dant halfway, less
the diaphragm the diaphragm abundant towards sparse towards less abundant abundant towards
the diaphragm aperture towards aperture aperture
Ramenta size and shape largest at base smallest and solitary smallest and solitary smallest and solitary solitary at base largest and solitary smallest at base smallest and solitary at
slightly smaller at base, larger and at base, larger and at base, abruptly more sparse and at base, smaller and and diaphragm, base, largest more
towards aperture more clustered more clustered larger and more clustered towards more clustered largest halfway up the clustered halfway up,
not clustered towards the aper- towards the aper- clustered towards aperture towards aperture tube, not clustered smaller and more clus-
ture (‘windows’) ture (‘windows’) the diaphragm tered towards aperture
Windows absent present present present only in absent absent absent absent
large flowers
Anther number 11–14 10 –11 10 –18 14 –16(– 23) 20– 21 19– 24 10– 22 26– 40
Tetrastigma host Tetrastigma sp. Tetrastigma sp. T. leucostaphylum, Tetrastigma sp. or T. cf. loheri Tetrastigma sp. T. loheri T. papillosum
T. cf. loheri, T. sp. T. pisicarpum
Distribution Luzon Panay Luzon and Samar Luzon Luzon Panay and Negros Mindanao Mindanao
Table 1 Character comparison between Rafflesia species in the Philippines.
J.F. Barcelona et al.: Philippine Rafesia
growing outside protected areas. The population at Bolos Point
is, however, located in the proposed north-eastern Cagayan
Protected Area Landscape, thus helping to emphasize the im-
portance of this area receiving protected status. Rafflesia manil-
lana should therefore still be considered rare and endangered
(Tan et al. 1986, Gruèzo 1990, Meijer 1997, Madulid 2000, Nais
2001, Barcelona & Fernando 2002) and is currently classified
as Critically Endangered (DENR-DAO 2007-01).
Rafflesia mira Fernando & Ong — Plate 3k
Rafflesia mira Fernando & Ong (2005) 267. — Type: Fernando & Ng 1653
(immature bud, LBC).
Rafflesia magnifica Madulid, Tandang & Agoo (2006, ‘2005’) 3. — Type:
Badilla 001 (PNH).
Diagnostic characters — With a floral diam of 45 60 cm,
R. mira, like R. speciosa, belongs to Meijer’s medium-sized
Rafflesia species (Meijer 1997). The flowers are coloured with
different hues of orange and reddish- or rusty-brown. Rafflesia
mira has a diaphragm that is nearly smooth (i.e., with none or
only shallow impressions of the perigone warts) and slightly
darker in colour than the perigone lobes in newly open flowers,
but lighter in colour than the perigone lobes with age. In R. mira,
a dark red ring surrounds the rim of the diaphragm aperture.
The perigone lobes have whitish rounded warts that are free but
interspersed with smaller ones. These small warts also line the
margin of the perigone lobes. The disk processes are organized
in 4 distinct zones and this arrangement is quite characteristic
for this species. The innermost, central processes are solitary
and more or less conical. They are surrounded by laterally
compressed, blade-like processes that are smaller and nar-
rower than the similarly compressed third zone perpendicular
to it. The third layer occupies nearly half of the disk diameter.
The outermost zone is composed of smaller and narrower
Taxonomic notes — Examination of their types and proto-
logues showed that R. mira and R. magnifica are two names
for the same species (Barcelona et al. 2007). Discrepancies in
size measurements in the protologues are perhaps due to the
fact that the type of R. mira is an immature bud. The descrip-
tion in the protologue of R. mira was based only on senescent
flowers and some buds, and colour descriptions were based
on photographs (E.S. Fernando, University of the Philippines,
Los Baños, pers. comm.). Rafflesia magnifica was published
in July 2006, despite the publication date of 2005 mentioned
in the protologue and is a later synonym.
Distribution — Mindanao. This species has only been re-
corded on Mt Candalaga in Maragusan Municipality, Compos-
tela Valley Province.
Ecology & Conservation — Unlike other Rafflesia species
that flower the whole year round (although flowering seems
to peak from March to May), R. mira flowers from August
to November. This species is restricted to semi-open habi-
tats, especially near waterfalls, in mid-montane rain forests at
c. 900 m. Its hosts have been identified as Tetrastigma loheri
(Fernando & Ong 2005) and T. mutabile (Blume) Planch. (listed
as T. tuberculatum (Blume) Latiff, a nom. illeg. in Madulid et
al. 2006). The populations of R. mira are currently not in a na-
tionally declared protected area. Rafflesia mira is only known
from populations that are extremely vulnerable to human
disturbance. The presence of Rafflesia on Mt Candalaga has
been the main attraction of ecotourism activities in Compostela
Valley Province, especially during the peak flowering months.
Accordingly, R. mira flowers are occasionally being brought
down from the mountain for visitors to see, a practice that greatly
endangers the survival of these populations.
Rafflesia philippensis Blanco — Plate 1a, b, 2e, 3d
Rafflesia philippensis Blanco (1845) 565. — Type: Azaola s.n. (not pre-
served). Neotype designated here: Barcelona, Cajano & Mendua 3345
(PNH; iso CAHUP).
Rafflesia banahawensis Madulid, Villariba & Agoo (2007, ‘2006’) 45. — Type:
MEUF 101 (PNH n.v.).
Rafflesia banahaw Barcelona, Pelser & Cajano (2007) 346. — Type: Barce-
lona, Cajano & Mendua 3345 (holo PNH; iso CAHUP).
Diagnostic characters — Rafflesia philippensis belongs among
the small-sized Rafflesia, producing flowers with a diam of 17.5–
27(–32?) cm. The flowers are dark red or maroon, less often
orange in fresh blooms. As in R. baletei, the warts on the per-
igone lobes are powdery white, prominent, variably shaped,
and often confluent and elongated. The diaphragm is conspicu-
ously rugose, 8–13 cm diam and has an often oval aperture
of 2.5 6 cm; the rim is whitish and resembles the margin of
the perigone lobes. Unlike the similarly-sized R. manillana and
R. lobata, windows (Nais 2001) or white blots (Meijer 1984)
in the perigone tube of R. philippensis are elongated and
prominent only in larger flowers. The disk is 6– 8.5 cm diam and
carries variably shaped processes that are up to 1.5 cm long.
The ramenta are polymorphic, up to 5 mm long, and glabrous.
Those inside the perigone tube are more or less solitary and less
branched than those inside the diaphragm which are clustered,
more dense and stout, but becoming nearly absent towards the
diaphragm rim. This does not conform with the protologue of
R. banahawensis (a synonym of R. philippensis, see below)
that claims the ramenta are uniformly filiform. The anthers are
14–23 in number and deeply immersed in the anther sulci.
Taxonomic notes — Rafflesia philippensis was described by
Blanco in the second edition of his Flora de Filipinas (1845)
based on specimens from Monte de Majaijai (= Mt Banahaw),
Luzon collected by Iñigo Gonzales y Azaola on 20 April 1840.
Unfortunately, Blanco did not preserve the type. Later, Merrill
(1918: 135) selected a specimen from Mt Makiling (W.H. Brown
s.n., Species Blancoanae 535, PNH lost, US904212) as repre-
sentative for R. philippensis and listed it, with R. lagascae, as
a synonym of R. manillana. After Azaola’s discovery of the
two species, Rafflesia was not again found on the mountain
until recently when a Rafflesia species was encountered and
described as R. banahawensis by Madulid et al. (2007) and
also R. banahaw by Barcelona et al. (2007). Both teams of re-
searchers, however, overlooked the close similarities between
this taxon and R. philippensis. After studying Blanco’s descrip-
tion (1845), we conclude that these three names conform with
the same species and that the specimen that Merrill selected
as representative of R. philippensis is actually R. manillana. In
Blanco’s description of R. philippensis, he records what he calls
the ‘calyx’ as being rough and somewhat woody. This seems
to resemble the conspicuous, yet finely rugose diaphragm
of R. banahawensis. In addition, the size of the male flower
(9 inches or 22.86 cm) in Blanco’s description is within the
size range of R. banahawensis (17.5– 32 cm), although also
in the range of most small-sized Philippine Rafflesia, such as
R. manillana from Luzon, R. lobata, R. baletei, and Rafflesia
sp. from Quirino Prov., northern Luzon (but see discussion
under R. manillana). The number of anthers (10), on the other
hand, is more within the range of R. manillana from Samar
(10–12) rather than R. manillana from Luzon (14–18) or R. bana-
hawensis (14–16(– 23)). However, since only a few flowers of
R. manillana were sampled and only one male flower of R. philip-
pensis was described by Blanco, it may very well be that the
discrepancy in anther number is not consistent. In Rafflesia,
the range of quantitative morphological measurements (such
as flower diameter and number of anthers) in different flowers
of the same species or even in different flowers from the same
host can be large (Table 1; Madulid & Agoo 2008: t. 1). For
88 Blumea – Volume 54, 2009
Plate 4 a–g. Habitat of Philippine Rafflesia species. a. R. manillana along a hiking trail, Mt Natib; b. karst limestone forest home to R. manillana, Bolos Point;
c. R. leonardi on a stream bank, Kanapawan; d. forest patches containing R. speciosa amongst grass fields, San Remegio; e. rocky habitat of R. baletei,
Mt Isarog; f. limestone outcrop near R. lobata site, San Remegio; g. forest patch bordered by slash-and-burn area home to R. schadenbergiana, Baungon;
h. Ecotourism facilities for R. schadenbergiana, Baungon. — Photos by: a–d, f –h: J.F. Barcelona; e: M.O. Cajano.
g h
e f
J.F. Barcelona et al.: Philippine Rafesia
instance, the holotypes of R. banahawensis and R. banahaw
came from a single host plant but the measurements of the
flower diam given in both protologues are not even overlap-
ping (29.5–32 cm in Madulid et al. (2007) and 17.5 27 cm in
Barcelona et al. (2007))! On the basis of Blanco’s descriptions,
we therefore conclude that R. philippensis is the same species
as R. banahawensis.
Distribution — Luzon, Laguna and Quezon Provinces, Mt
Ecology & Conservation — Rafflesia philippensis occurs at
720–750 m in recovering lowland dipterocarp forest. Madulid
et al. (2007) list Tetrastigma pisicarpum (Miq.) Planch. as its
host. The five known populations are found on steep slopes
and beside seasonal creeks and rivers on well-drained sandy
soil with dense herbaceous covering or thick leaf litter (Plate
2e) (Barcelona et al. 2007). Most populations are situated in
disturbed habitats, such as along trails, margins of vegetable
gardens, and near campsites. For decades, Mt Banahaw
has been a popular tourist destination, attracting hundreds of
thousands of visitors. In 2004, in an effort to relieve pressure
on the area, the Mt Banahaw-San Cristobal Landscape was
declared a Protected Area and was temporarily closed to the
public for rehabilitation. The discovery of R. philippensis came
two years after this closure and is perhaps a sign of recovery
of the area.
Rafflesia schadenbergiana Göpp. — Plate 1c, 2g, 3l– n, 4g, h
Rafflesia schadenbergiana Göpp. (in Hieron. 1885, ‘1884’) 35. — Type: Scha-
denberg & Koch s.n. (holo K; iso WRSL n.v.)
Local names — Kolon Busáw (Higaonon); Bó-o (Bagobo).
Diagnostic characters — Rafflesia schadenbergiana is the
largest flower in the Philippines measuring between 52 (Barce-
lona et al. 3342, PNH) and 80 cm diam when fully expanded.
A collection of one fully open male flower (Barcelona et al.
3357, PNH) is 70 cm diam, 22 cm tall, and weighs c. 5 kg. The
cupule is c. 5 cm long, 10 –16 cm wide and has bracts 17– 21
by 12 –15 cm. The perigone lobes are 20 23 by 22 26 cm,
orange brown with whitish warts in fresh blooms, but becoming
dark maroon with age. The warts on the perigone lobes are 2 3
mm tall from the perigone surface, the largest being 0.8 by 12
cm. They are variously sized and shaped, the larger ones being
conspicuously elongated. The diaphragm is c. 33 cm diam and
6–13 cm wide from the junction of the perigone attachment to
the aperture rim. Its upper surface is rugose because of c. 3
mm deep impressions of the perigone warts. The diaphragm
aperture is 13–15 cm diam with a c. 3 mm wide tannish ring
around the rim. The disk is 12–18 cm diam, c. 2 cm thick, c. 5
cm high from the perigone tube floor to the surface of the disk
and pale orange brown or tan with a raised rim c. 2 cm high. A
total of about 30 50 (to 63 in a large senescent flower) up to
3 cm long cone-shaped processes are arranged in 3 concen-
tric rings (the outermost, middle, and innermost rings of one
flower we studied are composed of 27, 14, and 9 processes,
respectively). The perigone tube lacks windows and is c. 22
cm high from the floor of the tube to the rim of the diaphragm.
The ramenta are 4–10 mm long, maroon with darker tips, and
often branched from the middle. Those at the base or on the
floor of the perigone tube are sparse and filiform, halfway up
the tube they are most dense, and those close to the rim of
the diaphragm are up to 4– 5 mm long, stout, and clustered
in groups. Male flowers have 26 40 anthers. The base of a
developing fruit measures c. 14 cm diameter. A collection of
an immature female bud (Barcelona et al. 3358, PNH) has a
diameter of 16 cm. The disk of this specimen is 17 cm diam
and 2 cm thick. The column is 12 cm high from the attachment
on the host plant to the surface of the disk. The column neck is
1 cm long and 14 cm wide. The ovary is lunate in longitudinal
section, 8 cm wide and 1.5 cm high. The annulus is c. 3.5 cm
Distribution — Mindanao. Rafflesia schadenbergiana was
first collected on Mt Parág near Mt Apo on Mindanao in 1882
(Lays 2006). Despite search efforts in recent times (e.g.,
Heaney & Regalado 1998, Nais 2001), it was not encountered
for more than 100 years and was even thought to be extinct
(Barcelona et al. 2006). In 1994, however, a flower bud of this
species was found in South Cotabato Province in an area lo-
cally named Sugud Ebang in the vicinity of Mt Temlofung (Lays
2006) and in 2007, a third locality was discovered at the foot
of Mt Kitanglad in Bukidnon Province, about 150 km NNW of
the type locality at c. 820 m (Barcelona 2007, Barcelona et al.
2008b). The distributional area of the largest Rafflesia of the
Philippines, therefore, seems to cover a large part of Mindanao.
The reported finding of R. schadenbergiana on Mt Matutum is
erroneous (see Nais 2001: 98, 175).
Ecology & Conservation — Rafflesia schadenbergiana has
been reported from old growth primary mountain forest at 1 271 m
in South Cotabato Province (Lays 2006) and in a small patch
of secondary forest in the vicinity of a river on Mt Kitanglad at
c. 820 m (Barcelona 2007, Barcelona et al. 2008b). The latter
population borders a slash-and-burn area (Plate 2g, 4g) and
relies on a single host plant. This host, Tetrastigma papillosum
Planch. (Barcelona 3343 with Antoque and Barcelona et al.
3360, PNH), has a dbh of c. 15 cm (Plate 1c).
The R. schadenbergiana population described by Barcelona
(2007) and Barcelona et al. (2008b) is located outside of the Mt
Kitanglad Range Natural Park, a protected area, and although
initial steps were taken to protect the plants and their habitat
(Barcelona et al. 2008b), a visit to the area in November 2007
showed considerable damage resulting from unsustainable eco-
tourism activities. The site was converted into a mountain resort
where the immediate vicinity was cleared and planted with or-
namental plants. Native huts were established as resting areas
for potential visitors (Plate 4g, h). We found several aborted
buds and have witnessed the intentional search for Rafflesia
buds and flowers; activities which subject the Rafflesia plants
and the roots of their host vine to trampling by caretakers and
visitors. Potentially, the clearing of the immediate vicinity also
endangers seed germination and exposes seeds and buds to
predation. In May 2008, a workshop on a conservation strategy
for R. schadenbergiana was conducted by the DENR with the
barangay officials, Local Government of Baungon Municipality,
representatives from the Department of Tourism, parasitic plant
experts, and the landowner and as of this writing, a conserva-
tion action plan is being prepared. We now have information
that another population of a large-sized Rafflesia, potentially
R. schadenbergiana, is found inside the protected area. Flow-
ering specimens were, however, not encountered in this new
population, and only buds and senescent flowers were seen
and photographed. Currently, the best conservation measure
for this population is not to disclose its exact location until a
conservation strategy has been developed. So, although not
extinct as was assumed until recently (Barcelona et al. 2006),
R. schadenbergiana is extremely rare and one of its two (per-
haps three) known and active populations is Critically Endan-
gered (DENR-DAO 2007-01).
The strong unpleasant flower odour was noted by the first
collector, a German pharmacist practicing in the Philippines,
Alexander Schadenberg, who for that reason was reported to
be very upset when the species was given his name (Anony-
mous 1930).
90 Blumea – Volume 54, 2009
Rafflesia speciosa Barcelona & Fernando — Plate 1e, 2h,
3j, 4d
Rafflesia speciosa Barcelona & Fernando (2002) 648. — Type: Barcelona
1221 (holo PNH; iso LBC).
Local names — Urúy, Kalò Posong, Agong-ong (Karay-a).
Diagnostic characters — Fully expanded flowers of R. spe-
ciosa range from 45– 56 cm diameter. The perigone lobes are
generally dark-, reddish- or rusty-brown, but become paler
with age. The white warts on the perigone lobes are small
and irregular in shape and are often free and elongated. The
diaphragm is usually darker than the perigone lobes and has
an almost smooth surface with numerous small and irregular
white specks which are most prominent in new blooms; its rim
is whitish becoming concolorous with age. The disk is yellow-or-
ange, but becomes more reddish orange near the rim. Rafflesia
speciosa has 17–31 processes which are usually arranged in
2 or 3 concentric rings pointing outward towards the rim. This
species is larger than most other Philippine Rafflesia, similar
in size to R. mira and small flowers of R. schadenbergiana.
It is clearly different from both those species in flower colour,
the shape and pattern of the warts on the perigone lobes,
diaphragm morphology, and the shape and number of the
Distribution — Panay and Negros. Rafflesia speciosa was
described from Mt Poras in Antique Province in Panay Island,
but has also been reported from two other sites in Panay: the
mountains in San Remegio and Valderrama Municipalities
(Antique) and the area spanned by the adjacent towns of Ig-
baras, Leon, and San Joaquin (Iloilo Province). It was initially
assumed that R. speciosa was endemic to Panay Island, but
photographic evidence (Pastor L. Malabrigo Jr., University of the
Philippines, Los Baños, pers. comm.) indicates it also occurs on
the lower slopes of Canlaon volcano in Negros. The presence of
R. speciosa in both Panay and Negros Islands concurs with the
Negros-Panay Faunal Region, a large late Pleistocene Island
that was formed when the sea level dropped to a maximum of
120 m below the present level with the development of conti-
nental ice sheets (Heaney 1986, Heaney & Rickart 1990).
Ecology & Conservation — Rafflesia speciosa grows at
190–800 m in lowland secondary forest patches on well-
drained soils, in gullies, and old reforested, generally dry areas
under thick leaf litter. The known populations of R. speciosa
are vulnerable as their habitat is threatened by slash-and-burn
agriculture (Plate 4d). Only the populations in Sibalom and
San Remegio Municipalities (Sibalom Natural Park) in Antique,
and the population in Negros Island are located in protected
areas and the species is categorized as Critically Endangered
(DENR-DAO 2007-01).
Rafflesia sp. — Plate 3b
This species from the Sierra Madre Mountain Range in Luzon
(Barcelona et al. 2006, 2007) is described in a separate paper
(Barcelona et al. in press). It resembles R. tengku-adlinii from
Sabah in Borneo in general appearance and floral size and
colour. It is, however, different in perigone ornamentation, shape
of disk processes, ramenta morphology, length, and disposition,
and number of anthers.
Distribution — Luzon. Currently known only from a single
locality within the Sierra Madre Mountain Range in Quirino
Ecology & Conservation — The population occurs at c. 450 m
in a disturbed lowland dipterocarp forest. The flowers form only
on the prostrate stems and underground roots and have not
been found to grow in the climbing stems of the host. Although
small-scale logging and swidden agriculture are prevalent in the
area, commercial open-pit mining for gold and copper poses
the most serious threat for this Rafflesia habitat. Despite the
establishment of the Quirino Protected Landscape, these mining
activities continue to seriously jeopardize the survival of this
Rafflesia species.
A small-flowered Rafflesia species from
Mt Matutum, Mindanao
The finding in the 1980s of Rafflesia buds on the lower slopes
of Mt Matutum was first reported by Nais (2001), who suggested
that these belong to R. schadenbergiana. However, examination
in 2002 of material preserved at Central Mindanao University
together with an available photograph of the source population
composed of senescent flowers and buds (Barcelona et al.
2008b), shows that the collected specimen belongs to a small-
flowered Rafflesia species. The material was unfortunately too
deteriorated to determine whether or not it represents a new
species for the Philippines (Barcelona et al. 2006, 2007).
The lowland tropical rain forest is one of the most threatened
forest types in the Philippines and other tropical areas, as
listed in World’s Biodiversity Hotspots (Mittermeier et al. 1997,
Myers et al. 2000). Habitat loss due to logging, mining and
the conversion of forest into farmland are among the greatest
threats faced by Philippine lowland forests. While the conser-
vation importance of these forests is widely recognized (e.g.,
Heaney & Regalado 1998, Mallari et al. 2001, Heaney & Mal-
lari 2002, Ong et al. 2002), efforts to design effective lowland
forest conservation strategies are hampered by a lack of data
on their current distribution, the extent to which they have been
damaged and destroyed by human impact, and the biodiver-
sity they still contain. Philippine Rafflesia and the bonanza of
recent discoveries in this iconic genus highlight how little is
known about the biodiversity and ecology of lowland forests
and how fragile and endangered the species are that rely on
this habitat.
Within a period of about six years, the number of Rafflesia spe-
cies thought to be present in the Philippines increased nearly
fivefold from two species known before 2002 to ten or eleven
presently recognized. If these newly discovered members of the
genus with the largest flowers of all flowering plants have been
overlooked for centuries and, in some cases, even in areas that
have been frequently explored by botanists and are among the
most popular Philippine tourist destinations (e.g., R. philippensis
on Mt Banahaw), what does this tell us about our estimates
of the species diversity of organisms in these forests that are
much less conspicuous or sought after, such as arthropods or
cryptogams? Furthermore, these recent findings indicate how
little is known about the ecology of Philippine forests. Raf-
flesia populations seem to consist of few individuals and are
frequently far apart, as is the case for many plant species in
tropical rain forests, especially trees. Data on the extent of gene
flow between such remote populations is, however, wanting. In
addition, hardly anything is known about the distances Rafflesia
pollen and seeds travel, and how the seeds are dispersed. In
the absence of such information, it is impossible to obtain an
accurate estimate of the effects of habitat fragmentation on
the survival of Rafflesia, a situation that is relevant to many
other inhabitants of lowland forests as well. Rafflesia is also a
wonderful example of the intimate way in which many species
of the lowland rain forest are dependent upon each other, and
also of how poorly studied these interactions are. Because Raf-
flesia is a holoparasite of the vine Tetrastigma, its fate depends
J.F. Barcelona et al.: Philippine Rafesia
entirely on the occurrence and well-being of the host plant in
a particular area. We now know that one Tetrastigma species,
T. rafflesiae Miq. (syn. T. leucostaphylum (Dennst.) Alston
ex Mabb., Veldkamp 2008), is host to at least ten species of
Rafflesia, including R. manillana (Nais 2001), and that T. papil-
losum, cited by Nais (2001) as host to R. pricei and R. kerrii,
is also the host of R. schadenbergiana. Furthermore, our field
observations reveal that at least two species of Tetrastigma are
parasitized by R. manillana (Plate 1d, f, g). As far as is currently
known, the remainder of the species of Rafflesia only parasitize
one species of Tetrastigma. Notwithstanding these facts, we
still know little about host-parasite specificity and to what extent
Tetrastigma and Rafflesia are coevolving.
Although the recent discoveries of new species and populations
of Philippine Rafflesia have infused the biological community
with excitement, especially in the Philippines, these findings
also have caused great concern among scientists and environ-
mentalists. All the newly discovered species may be seriously
threatened by extinction. Many of them are found in severely
degraded forests and are threatened by habitat destruction.
In addition to logging and conversion of lowland forest into
farmland (Plate 2g, 4d, f), another, less familiar threat facing
Philippine Rafflesia is unsustainable or poorly planned ecotour-
ism. The discovery of new species or populations of Rafflesia
is often almost immediately followed by the construction of
facilities to attract tourists, such as trails, fences, and viewing
platforms; frequently even before conservation action plans can
be carried out by the Department of Environment and Natural
Resources (DENR). These activities together with clearing of
the area and the search for flowers and buds can be detrimental
to a Rafflesia population, as we witnessed in Panay, where
such activities resulted in the extinction of a population of Raf-
flesia. On Mt Kitanglad, the population of R. schadenbergiana
within a parcel of land tilled under a Community Based Forest
Management (CBFM) agreement with the DENR (but outside
of the buffer zone of the Mt Kitanglad Range Natural Park) is
similarly being ‘developed’ for ecotourism (Plate 4g, h). The
ecotourism aspect of Rafflesia conservation can be very useful
in education and appreciation of our biodiversity (Plate 3o, p), if
implemented judiciously. Establishing active Rafflesia sites as
ecotourism attractions, therefore, has to be carefully planned
and monitored. Ideally, this should remain confined to areas that
contain many Rafflesia populations. For ecotourism develop-
ment to be more meaningful and not detrimental to the plants,
consultations with the DENR, local governments, Department
of Tourism (DOT), the academic communities, and scientists
should be done before opening these Rafflesia sites to the
public. Populations that are more accessible could be used for
education and ecotourism purposes, whereas those that are
in the forest interior and far from human habitation should be
pristinely preserved and scientifically studied.
As with most plants and animals in Philippine forests, Rafflesia
is currently poorly protected against unsustainable forest use
and destruction. Among the Philippine Rafflesia species, only
R. baletei, R. philippensis, R. speciosa, a few populations of
R. manillana, R. schadenbergiana, and the only population of
Rafflesia sp., are found within protected areas. Currently, of
the nine recognized species of Rafflesia in the Philippines, only
three, R. manillana, R. schadenbergiana and R. speciosa, are
included on the National Red List of Threatened Plants (DENR
Administrative Order No. 2007-01). At the time this list was
drafted, the other species (R. baletei, R. leonardi, R. lobata,
R. mira, R. philippensis, and the Rafflesia species found in
Quirino Province) were not yet formally described or their taxo-
nomic identity was still doubtful. The DAO is amendable every
three years and considering the rare and often endangered
status of Philippine Rafflesia species, it is strongly recom-
mended that they be added to the list in 2010. In addition to
pursuing the protection of Rafflesia species and their habitat,
cultivation experiments could perhaps help to relieve current
active populations from pressure by unsustainable ecotourism.
Artificial inoculation of Tetrastigma plants has been successfully
done in Java and Malaysia (Nais 2001, Veldkamp 2007) and
has helped in boosting both ecotourism and public awareness
in the latter country.
The history of deforestation of the Philippines, between the
1950s until late 1980s, was demonstrated by Kummer (1992)
to be a poorly documented and highly politicized phenomenon.
Forest cover statistics were plagued by incomplete, conven-
iently lost or manipulated data, rendering analysis of trends
and causes nearly impossible. The forest cover situation of
the Philippines during the 1990s to the present, beyond the
period covered by Kummer’s dissertation, continues to decline,
although claims by the Forest Management Bureau (FMB) of
the DENR are to the contrary. A much-cited figure of 18.3 %
remaining primary and residual forest as of 1999 was made by
the Environmental Science for Social Change (ESSC 1999),
and depending on the presence or absence of governmental
intervention, is estimated to increase to 19 % or further decline
to 6.6 % in 2010, respectively.
One principal gap in all available forest cover data and forest
loss projections is the lack of proper classifications of forest
types to accompany the statistics; open canopy forest, close
canopy forest, production forest, secondary forest, sub-mar-
ginal forest, old-growth forest, and other logging terminologies
passed on as forest types, continue to be used. Lost in these
hazy terminologies and the murky statistics associated with
them is the focus on the lowland forest, the most severely
threatened forest ecosystem of the Philippines.
As in most tropical regions, the lowland forest is the most utilized
resource in the country and has been intensively exploited, re-
sulting in forest fragmentation and massive habitat destruction.
Mallari et al. (2001) documented the various threats to most
of the remaining forest fragments in the country. For instance,
both legal and illegal logging had been conducted and is still
ongoing mostly in the dipterocarp forests on larger islands of
the country, and to some extent, in forests over limestone (also
known as molave forests, e.g. Palawan, Polillo, Samar). Exten-
sive mining and quarrying are conducted in ultramafic forests
(e.g., Eastern Mindanao, Palawan, Zambales) and forests over
limestone (e.g. Sierra Madre) while conversion to farmlands
continues unabated in freshwater swamps and peat swamp
forests (e.g., Agusan Marsh, Liguasan Marsh). Few studies of
these habitats have been conducted and precious little is known
of their current status. At present, with the exception of some
data on dipterocarp forests (e.g. Guiang 2001), no available
statistics exist on the other lowland forest types with regard to
their ongoing exploitation and loss.
The newly described species of Rafflesia and the rediscovered
populations of two previously known ones underscore the dilem-
ma of securing the conservation of the lowland biodiversity
in the face of continuing degradation and conflicting forestry
policies and priorities. All known Rafflesia species in the Philip-
pines occur in forest whose conditions range from regenerating
or secondary to severely degraded. Except for a population of
R. schadenbergiana reported at 1 271 m in South Cotabato
and of R. manillana at 1 200 m on Mt Irid, all the other species
are found below 1 000 m and most are found outside of pro-
tected areas. But even within protected areas, conservation of
92 Blumea – Volume 54, 2009
Rafflesia is a big challenge. Lowland areas are given very low
conservation priority to begin with, and considered of marginal
conservation value by previous park planners in the Philippines,
resulting in the poor representation of lowland habitats in pro-
tected areas of the country, particularly on Luzon and Mindanao
(MacKinnon 2002) which, incidentally, are also the islands with
the highest diversity of Rafflesia (Map 1). Then, secondary or
severely degraded lowland forest within a protected area is
typically the core area for multiple-use zone: characterized by
extractive activities of tenured migrants, indigenous peoples,
and residents of adjacent local communities, or delineated as
buffer zone at most. In addition to Rafflesia’s poor representa-
tion in protected areas, this iconic plant also receives low con-
servation management priority. Attempts to reduce coverage
of protected areas for other landuses sometimes still succeed,
such as in the case of Mt Malindang Range Natural Park (Roxas
2005), and will continue to threaten Rafflesia populations even
within protected areas. Presently, no data are available regard-
ing management zoning strategies for protected areas where
Rafflesia species are found. Thus, we recommend a review of
current management zoning criteria to reflect the importance of
the lowland forest in the overall strategy to conserve Philippine
biodiversity in protected areas. We also recommend further
research to document the conservation status of the lowland
forest in the Philippines and its associated biodiversity. While
an array of conservation interventions have been implemented
in the country to ensure the protection of its remarkably unique
biodiversity and to arrest the various conservation threats (e.g.,
Bagadion et al. 2000), none focused specifically on lowland
Acknowledgements We are grateful to the staff of the Department of
Environment and Natural Resources (DENR), namely, M.S. Lim, Director
Protected Areas and Wildlife Bureau (PAWB), A.C. Manila, Chief, Wildlife
Division, PAWB, and staff of the DENR Regional and local offices for facilitat-
ing the issuance of collecting and transport permits. We thank the following
persons for sharing photographs and information on current distributional
ranges: P.L. Malabrigo Jr., E. S. Fernando, I. L. Lit Jr., and M.O. Cajano of
the University of the Philippines at Los Baños in Laguna, N.A. Bartolome,
Conservation International, Philippines, B. van Ee, Harvard University, D.L.
Nickrent, Southern Illinois University, Cagayan Valley Partners in People
Development (CAVAPPED) through its President/CEO, P.A. Visorro, A.G.
Lenaming and I. Grasparil of The Antique Outdoors (TAO), R.L. Martin Jr.,
N. Antoque, Tanggol Kalikasan through E.S. Lim Jr., the Candelaria Family,
Mayor A.J. Roa of Baungon Bukidnon, Barangay Captain F. C. Babion, and
the Antoque and Laque Families. The Field Museum, Chicago, IL through
L.R. Heaney provided opportunity for field trips to some of the Rafflesia
sites. N.T. Winn (Department of Geography, Miami University) helped us to
create the distribution map and J.F. Veldkamp (Nationaal Herbarium Neder-
land, Leiden) provided copies of the Philippine Rafflesia protologues and
suggestions to improve our manuscript. E.J. Tepe (University of Utah) and
M. Paz Moreno (University of Cincinnati) translated Blanco’s Flora de Filipinas
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... Their work also suggests that the ancestral range of Rafflesia might have originated in nearby Borneo and that lineages may have evolved earlier and more gradually than considered previously. Taken together, an explosive flurry of species discoveries (Barcelona et al. 2009b), coupled with insightful phylogenetic analysis (Pelser et al. 2019), reveals the Philippines to be an area of great promise for research into species richness and phylogeography in the genus Rafflesia, and an important region for future focus. A high level of species endemism, and the absence from conservation strategies, in a context of high anthropic change highlights the urgent need for conservation of Rafflesia in the Philippines, which we discuss. ...
... The Rafflesia spp. on Luzon Island have been particularly confused, despite nearly a century and a half of botanical exploration in the region. For example R. banahawensis Madulid, Villariba-Tolentino & Agoo [as R. philippensis in Barcelona et al. 2009b;Blanco 1845] in the mountains of the Banahaw-San Cristobal Protected Landscape (Barcelona et al. 2008b;Madulid et al. 2006;Pelser et al. 2013) and R. panchoana Madulid, Buot & Agoo in the Mount Makiling Forest reserve (Madulid et al. , 2012 [as R. manillana in Fernando & ong 2005a; as R. lagascae in Barcelona et al. 2009cBarcelona et al. , 2011Pelser et al. 2013] were both overlooked until recently, and synonymised under R. manillana, a distinct species from Basey, Samar Island . This confusion emphasizes the need for a concerted and coordinated effort to explore and define species limits in the region. ...
... The genus tetrastigma is itself taxonomically complex, which has further hindered our understanding of the host specificity of Rafflesia. In most Rafflesia species, the infection process in the host vine is virtually unknown (Barcelona et al. 2009b;hidayati & Walck 2016;Thorogood et al. 2021). This has further implications for conservation; the lack of seed banking and propagation techniques makes ex situ conservation challenging, underscoring the importance of taxonomic exploration linked to in situ conservation. ...
The Southeast Asian genus Rafflesia (rafflesiaceae) is famous for possessing the world's largest flowers. All species are rare or threatened, so understanding taxonomic diversity in the genus is crucial for informing effective conservation practice. here we examine R. banaoana, a poorly known taxon from the remote montane rainforests of the Kalinga Province in the Philippines. This species has been treated as conspecific with R. leonardi, and overlooked in systematic studies. Using stable yet hitherto neglected features such as the stigmatic fascia surface, disk shape, process structure, annulus interior and exterior distinction, and ovary shape, we demonstrate that R. banaoana is morphologically as well as ecologically distinct from R. leonardi, and requires reinstatement at the specific rank. We present our findings in the broader context of complexity in the genus Rafflesia in the Philippines, now considered the center of diversity, with 15 species described to date. We highlight the taxonomically confused R. banaoana as a case for careful observation of previously unexamined morphological characters , as well as ecology, to avoid overlooking cryptic taxa or species complexes and to inform representative sampling in systematic treatments. Such an approach will be essential for enhancing our understanding of the diversity of this enigmatic yet poorly understood genus at a time of unprecedented anthropogenic change and species extinction. In light of our findings, we recommend a holistic approach to the conservation of Rafflesia in the Philippines.
... The Philippines is one of the centers of biodiversity of Rafflesia R.Br. (Brown, 1821;55 Rafflesiaceae), a Southeast Asian genus of obligate endo-holoparasitic plants growing in 56 primary and secondary rain forests (Meijer, 1997;Nais, 2001; Barcelona et al., 2009). The 57 ...
... ; doi: bioRxiv preprint stages of regeneration, across wide elevational ranges, and on different substrates (Nais, 584 2001;Barcelona et al., 2009). Yet, here we show that the environmental needs of some 585 ...
Full-text available
Premise Rafflesia are rare holoparasitic plants. In the Philippines, all but one species are found only on single islands. This study aimed to better understand the factors contributing to this distribution pattern. Specifically, we sought to determine whether narrow environmental tolerances of host and/or parasite species might explain their island endemicity, or, instead or in addition, the limited distribution of Rafflesia species is the result of a narrow overlap between the environmental requirements of host and parasite. Methods We used Maxent species distribution modeling to identify areas with suitable habitat for R. lagascae , R. lobata , and R. speciosa and their Tetrastigma host species. These analyses were carried out for current climate conditions as well as two future climate change scenarios. Key results Whereas species distribution models indicated suitable environmental conditions for the Tetrastigma host species in many parts of the Philippines, considerably fewer areas have suitable conditions for the three Rafflesia species. Some of these areas are found on islands from which they have not been reported. All three species will face significant threats as a result of climate change. For R. lagascae and R. lobata , these may include a loss of suitable area as a result of changes to the distribution of their host species. Conclusions Our results suggest that limited inter-island dispersal abilities and/or specific environmental requirements are likely responsible for the current pattern of island endemicity of the three Rafflesia species, rather than the environmental requirements of their Tetrastigma host species.
... Many of the populations documented in the last two decades are remote and fall outside PAs. In addition, they consist of few individuals and are highly threatened by logging, slash-and-burn agriculture, and other human disturbances; this emphasizes the need for local conservation strategies, as recommended by Barcelona, Pelser, et al. (2009) (Figure 3a). In recent decades, blooming events have been announced on social media through infographics (Figure 4), promoting awareness and community-driven protection. ...
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Societal Impact Statement Rafflesia is the genus that contains the world's largest flowers. Despite their global appeal, most of the 42 known species are now at risk of extinction. Urgent action is needed to protect these remarkable flowers. A combined approach to conservation is recommended, including a greater level of habitat protection and support for local community action groups. Rafflesia is a suitable new icon for conservation in the Asian tropics. Summary The genus Rafflesia , which includes the world's largest flowers, has aroused curiosity among scientists for centuries and features prominently in local culture across Southeast Asia. The plant has long been used in ethnobotanical medicine and, more recently, as a source of revenue from ecotourism. But despite its acclaim, Rafflesia remains poorly understood in many respects. Taxonomy is disputed, new species are described each year, and the plant has proven recalcitrant to cultivation. This has hindered conservation, and most of the 42 known species are now severely threatened, yet only one is listed by the International Union for Conservation of Nature (IUCN). We estimate that 60% of Rafflesia species face a severe risk of extinction (equivalent to Critically Endangered [CR]). Moreover, we predict that at least 67% of known habitats fall outside protected areas, exacerbating their vulnerability. Alarmingly, recent observations suggest taxa are still being eradicated before they are even known to science. We present recent scientific discoveries and probable extinctions and highlight case studies of conservation success, with a focus on the role of local people. We propose a multi‐pronged conservation approach combining strengthened taxonomy, ex situ propagation, ecotourism, and an extension of protected areas. We suggest action devolved to local communities and awareness campaigns linked to social media networks will be crucial outside of protected jurisdictions. Finally, we propose to establish Rafflesia as a new icon for plant conservation in the Asian tropics. A combined approach might just save some of the world's most remarkable flowers, most of which are now on the brink of being lost.
... There are about 40+ Rafflesia spp. endemic to the dwindling forests of tropical Asia with several species considered critically endangered (Barcelona et al., 2009;Pelser et al., 2019). Dubbed panda of the plant world, Rafflesia is a charismatic icon of plant conservation, but unlike the panda, efforts to conserve and cultivate Rafflesia out of its natural habitat have been limited and challenging (Molina et al., 2017;Wicaksono et al., 2016Wicaksono et al., , 2021. ...
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Rafflesia is of great interest as one of the only two plants known to have completely lost its chloroplast genome. Rafflesia is a holoparasite and an endophyte that lives inside the tissues of its host, a tropical grape vine (Tetrastigma), emerging only to bloom—with the largest flower of any plant. Here, we report the first Rafflesia seed transcriptome and compare it with those of other plants to deepen our understanding of its extraordinary life history. We assembled a transcriptome from RNA extracted from seeds of the Philippine endemic Rafflesia speciosa and compared this with those of other plants, including Arabidopsis, parasitic plants Striga and Cuscuta, and the mycoheterotrophic orchid Anoectochilus. Genetic and metabolic seed pathways in Rafflesia were generally similar to the other plant species. However, there were some notable exceptions. We found evidence of horizontal transfer of a gene potentially involved in circumventing host defenses. Moreover, we identified a possible convergence among parasitic plants because Rafflesia, Striga, and Cuscuta shared important similarities. We were unable to find evidence of genes involved in mycorrhizal symbiosis, suggesting that mycoheterotrophy is unlikely to play a role in Rafflesia parasitism. To date, ex situ propagation of Rafflesia by seed has been mostly unsuccessful. Our research is a bold step forward in understanding the fundamentals of Rafflesia seed biology that will inform the continued propagation and seed-banking efforts concerning this recalcitrant plant. We discuss our findings in the broader context of the conservation of a genus in peril.
... Java is one of the most densely populated areas in the world (Smiet 1990;Liu and Yamauchi 2014) with about 1121 people per km 2 (Higginbottom et al. 2019) resulting in the conversion of land to human settlements, the establishment of cities, and new agricultural land. Hence, habitat conversion and habitat loss are the main threats to Rafflesia on Java (Ismail 1988;Barcelona et al. 2009;Hidayati and Walck 2016). In addition, direct human activities such as damaging the flower out of sheer curiosity (Hidayati and Walck 2016) and using Rafflesia flowers as a remedy to treat fever, back pain, and to recover from childbirth also negatively affect populations (Ismail 1988;Meijer 1997;Hidayati and Walck 2016). ...
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Rafflesia species (Rafflesiaceae) are among the flagship plants of South-East Asian countries in which they occur. Three species of Rafflesia, i.e. Rafflesia patma, R. rochussenii, and R. zollingeriana, are known from Java, Indonesia. All three species are threatened with extinction due to human activities that cause habitat loss and fragmentation. Conservation efforts such as determining conservation units for prioritization of those species have been difficult due to the lack of data on their population genetics. Availability of genetic information is important to develop appropriate conservation measures. Our study evaluates genetic diversity and structure of the three Rafflesia species using a total of 166 samples across the island. We used single nucleotide polymorphism (SNP) markers obtained via MIG-seq. The three species of Rafflesia in Java bear much lower genetic diversity compared to what was previously shown for R. speciosa and R. lagascae on Borneo, the Philippines and the Malayan Peninsula. Low genetic diversity within the Javanese Rafflesia species, particularly in R. patma and R. zollingeriana, is attributed to bottleneck events and population expansion in the past. We also provide evidence of clonality and existence of different genotypes within Tetrastigma host plants in two species of Rafflesia. Scattered and fragmented populations as reconstructed in the genetic structure analyses are important to be considered in designing appropriate conservation strategies. Furthermore, we demonstrate how the establishment of Rafflesia ex-situ collections can conserve genetic diversity that may no longer be present in nature and could be used in future reintroduction programs.
... Climate change may negatively affect sexual reproduction in Hydnora if pollinators disappear and might limit seed dispersal. Despite Hydnora's sparse occurrence in the respective distribution areas, no conservation management is outlined for most parasitic plants, except for Rafflesia (Malpighiales) in Asia (Barcelona et al., 2009). In addition, they are being removed at a rapid rate for agricultural land expansion and overexploitation for medicinal use (Mkala et al., 2021). ...
One of the anthropogenic causes affecting species distribution is climate change, which has significant implications for species conservation. However, little is known about the effects of changes in parasitic plant distribution on community-level interactions. Parasitic flowering plants make a limited numerical contribution to biodiversity. Their lifestyle may exhibit a moderate to the high degree of host dependence. Because of this host dependence, parasites may be more affected by environmental changes, such as climate change, compared to autotrophic representatives. To our knowledge, the effects of different climate change scenarios and their environmental variables on parasitic plants and their hosts have not yet been studied. This study aimed to construct a model which shows the current and future potential effects of climate change on the distribution of the two holoparasitic plants Hydnora abyssinica A.Br., and H. africana Thunb. in comparison to their respective Fabaceae and Euphorbiaceae hosts. We projected the future distribution of these species and their host plants using five models, nine bioclimatic, and five environmental variables. The global circulation model (CMIP5) for the years 2050 and 2070, applying two representative concentration pathways scenarios (RCP4.5 and RCP8.5) projected a 41–64% contraction of suitable habitats for H. abyssinica. For H. africana, more stable conditions are estimated, with a 12–28% contraction in suitable habitats, making this species putatively less prone to climate change effects, although this species has a more restricted distribution compared to H. abyssinica. Because climate change could affect the host differently than the parasites, the impact on the parasite could potentially be exacerbated due to host plant dependence. The models predict that the host plant distribution will be less affected, except for Vachelia Karroo, Vachellia xanthophloea, and Euphorbia gregaria, which indicated high contraction (40–66%). The predicted host species distribution ranges will only partially overlap with the respective distribution of the parasite.
... Some of these plants are endemics in certain areas, for example, the Rafflesia sp. (Rafflesiaceae), which is only found in some areas of Southeast Asia; ranging from Sumatra, Java Islands, Borneo Island, Southern Thailand, Peninsular Malaysia and in the Philippine Islands (Barcelona et al., 2009;Erlinda et al., 2018;Farah Khaliz et al., 2018;Mat-Salleh et al., 2011;Meijer, 1984;Suwartini et al., 2008;Wiriadinata & Sari, 2011). The Rafflesia sp. can be found in several areas in Sabah; namely Crocker Range, Mount Trus Madi, Maliau Basin Conservation Area, Imbak Canyon Conservation Area and Danum Valley Conservation Area. ...
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In the vicinity of Kinabalu Park, Sabah, a study was conducted to determine the plant community and its composition in the habitat of Rafflesia sp. and its host, Tetrastigma sp. A total of 5 circular-shaped plots each with a fixed radius of 20 meters, were located around Kinabalu Park, namely in Losou Podi, Losou Minunsud, Sayap Substation, Langanan and Gansurai. The Rafflesia species detected in Kinabalu Park during the present study were Rafflesia pricei and R. keithii. Overall, 19 Rafflesia individuals were detected, which comprised of 3 flowers and 16 buds. A total of 20 scars from former dead flowers and buds were obtained on the host, where they possessed an average diameter of 2.2-4.8 cm from the five plots. There were 778 individuals recorded for plant community, belonging to 111 genera, 53 families and 250 species. The total tree density was 1238 individuals/ha, where the family Lauraceae (11.05%) had the highest individuals followed by Annonaceae (8.61%). Although the species Baccaurea lanceolata were found in all study plots, the species Xantophyllum macrophyllum has the most individuals detected (3.60%) in the plant community habitats. The value of the Shannon-Wiener Index was H'=3.23 and the Evenness Index is low, E=0.10. The percentage of family similarity between plots was high (SBC=70.19-48.23%), but the percentage of species similarity between plots was very low (SJ=4.31-1.54%). This study shows that both the species of Xanthophyllum macrophyllum and Baccaurea lanceolata have a relationship with the habitat of Rafflesia in Kinabalu Park, as both species were located nearest to the Rafflesia's host. Moreover, these two species were seen to be well associated with Tetrastigma since the Tetrastigma was observed to climb several trees of these species in the plot.
... The 'queen of parasites' is Rafflesia, some species of which have flowers over 1 m in diameter, the largest among all angiosperms 4 (Brunei Darussalam, 2000). At the time when the Philippines Rafflesia stamp was issued (2007), this species was known as R. manillana, but later taxonomic work 24 named it as R. lagascae (Figure 3 d). Both of the other genera in Rafflesiaceae have also been featured on stamps. ...
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It is proposed that philately and the study of parasitic plants can be conflated for educational purposes. Of the 12 lineages of parasitic flowering plants, eight are currently represented on postal stamps. The most frequent genus seen on stamps is Rafflesia, closely followed by Viscum. These stamps convey messages about the history and importance of parasitic plants such as witchweed (Striga), sandalwood and mistletoes. Some of the parasitic plants are beautiful wildflowers such as Castilleja, Euphrasia and Pedicularis, whereas many mistletoes in Loranthaceae have flowers that rival orchids. Countries with rich parasite floras that currently do not have stamps featuring these plants should consider them as worthy subjects.
... The subsequent discoveries of the species in South-east Asia, in particular on the islands of Java, Sumatera, Borneo and the Philippines are listed in Table 1. Barcelona et al.(2009); Barcelona and Pelser (2008); Barcelona et al.(2006); Galang and Madulid (2006); Fernando and Ong (2005); Susatya et al. (2005); Latiff and Wong (2003); Barcelona and Fernando (2002); Nais, (2001); Mat- Salleh and Latiff (1989); Meijer (1984); Teijsmann and Binnendjik (1850). Suringar R. hasseltii was discovered in 1877 by van Hasselt, Veth and Snelleman in Sumatera and later described by Suringar in 1879. ...
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Rafflesia R.Br. (Rafflesiaceae), is one of the most outstanding parasitic flowering plant genera. The genus can only be found in Southeast Asia: in Thailand, Malaysia, Brunei, the Philippines and Indonesia. To date, Malaysia has recorded 13 species, of which eight are reported from Peninsular Malaysia: R. cantleyi, R. azlanii, R. kerri, R. su-meiae, R. sharifah-hapsahiae, R. parvimaculata, R. tuanku-halimii and R. tiomanensis. In Sabah, three species can be found which include R. pricei, R. keithii and R. tengku-adlinii, whereas Sarawak has four species: R. hasseltii, R. keithii, R. pricei and R. tuan-mudae. The diverse species of Rafflesia in Malaysia have been used to promote Malaysia as an ecotourism destination. The reinforcement of laws and acts to conserve and protect this genus and its species will indirectly protect the tropical rainforest from encroachment activities.
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A new species of Rafflesia, R. baletei, from Mt Isarog in the Bicol Region, Southern Luzon, Philippines, is described. Rafflesia baletei is the fifth endemic species and the second of the small-sized species of the genus in the Philippines to have been described so far. It differs from the presumably closely related R. tengku-adlinii from Borneo in flower colour and size, perigone ornamentations, and number of anthers. Furthermore, it differs from the similarly-sized R. manillana from the Philippines in diaphragm and ramenta morphology and ornamentations, and flower habit.
More than one hundred years after its discovery on Mount Párag, Mindanao, Philippines, and never observed since, Philippine biggest flower : Rafflesia schadenbergiana Göppert, 1885, has been rediscovered in 1994 in the mountain rain forests of Southwestern Mindanao, in South Cotabato Province. A detailed description of the mature floral bud is provided.