A Review of the White-flowered Amorphophallus (Araceae: Thomsonieae) Species in Sarawak.

Abstract

A review of the white-flowered Amorphophallus species in Sarawak is presented. A total of five species are recognized, four of which belong to the Eburneus Group and are restricted to limestone, and moreover, locally
endemic: A. eburneus Bogner (Padawan and Tebedu areas), A. brachyphyllus Hett. (Bau), A. juliae sp. nov. (Merirai) and A. niahensis sp. nov. (Niah). A fifth species, Amorphophallus infundibuliformis Hett., A.Dearden & A.Vogel, of doubtful affinity, is widespread and locally abundant on a variety of substrates excluding limestone. A key to the white-flowered species in Sarawak is presented and all species are illustrated.

Full text

249
A Review of the White-flowered Amorphophallus Species in Sarawak
Gardens’ Bulletin Singapore 61 (2): 249-268. 2010
A Review of the White-owered Amorphophallus (Araceae:
Thomsonieae) Species in Sarawak
P.C. BOYCE 1, 2, I.B. IPOR 2 AND W.L.A. HETTERSCHEID 3
1 Visiting Scientist, Pusat Pengajian Sains Kajihayat
(School of Biological Sciences), Universiti Sains Malaysia
1180 USM, Pulau Pinang, Malaysia
Email: phymatarum@gmail.com
2 Herbarium (SAR), Forest Research Centre, Km 10 Jalan Datuk Amar Kalong
Ningkan, 93250 Kuching, Sarawak, Malaysia
3 Wageningen University Botanical Gardens, Gen. Foulkesweg 37
6703 BL Wageningen, Netherlands
Email: wilbert.hetterscheid@wur.nl
Abstract
A review of the white-flowered Amorphophallus species in Sarawak is
presented. A total of five species are recognized, four of which belong to
the Eburneus Group and are restricted to limestone, and moreover, locally
endemic: A. eburneus Bogner (Padawan and Tebedu areas), A. brachyphyllus
Hett. (Bau), A. juliae sp. nov. (Merirai) and A. niahensis sp. nov. (Niah).
A fifth species, Amorphophallus infundibuliformis Hett., A.Dearden &
A.Vogel, of doubtful affinity, is widespread and locally abundant on a variety
of substrates excluding limestone. A key to the white-flowered species in
Sarawak is presented and all species are illustrated.
Introduction
Fieldwork on forested limestone areas of Sarawak is proving remarkably
productive in revealing hitherto undescribed species of Amorphophallus.
As this paper exemplifies, even supposedly well-botanized areas can be
revealed to have new taxa and, thus, it is no great surprise that when remote
and not easily accessible limestone areas are scrutinized, these, too, prove to
have their complement of novel species.
Batu Niah is a significant limestone formation in Miri Division,
northeast Sarawak. Bukit Merirai is a smaller but more remote limestone
formation on the border of Kapit and Bintulu Divisons. Both areas are
geographically separated from the limestones of Mulu (Miri and Limbang
Divisions) and from the isolated Bukit Sarang limestones on the Bintulu/
Kapit Division border, and from areas further east in Sarawak and Sabah,
as too from the complex limestone formations in western Sarawak that

250 Gard. Bull. Singapore 61 (2) 2010
have received the most attention in recent years. Fieldwork in these areas
has shown that while such formations have aroid species in common, there
are also for each formation, suites of closely related but morphologically
distinct, presumably vicariant, local endemics. In addition to examples
in the genus Schismatoglottis (see especially Hay and Yuzammi, 2000),
and Alocasia (see Hay, 1998, 2000), this phenomenon is particularly well
exemplified by Amorphophallus, in which the species on limestone in
western Sarawak [A. eburneus Bogner (Bau limestone), A. brachyphyllus
Hett. (Padawan limestone), and from Serian (A. ranchanensis Ipor, Tawan,
A.Simon, Meekiong & Faud)] are mirrored in eastern Sarawak by the
recently described Mulu-endemic, A. julaihii Ipor, Tawan & P.C. Boyce, the
two novel species here described, and thence to Sabah where A. tinekeae
Hett. & A. Vogel is restricted to the limestone at Gua Gomontong.
The two novelties described here take to 17 the number indigenous
endemic Amorphophallus species recorded for Borneo (see also Mayo and
Widjaja, 1982; Bogner et al., 1985; Bogner, 1989; Bogner and Hetterscheid,
1992; Hetterscheid, 1994; Hetterscheid and van der Ham, 2001; Ipor et al.,
2004, 2007). Remarkably, 15 of these species have been described within the
past 30 years. Additionally, a further four species recorded for Borneo are
either introduced or of doubtfully native provenance: A. konjac K.Koch,
A.paeoniifolius (Dennst.) Nicolson, A. prainii Hook. f. and A. muelleri Blume.
Taxonomy
The limestone-obligate white-flowered Amorphophallus in Sarawak are
seemingly closely related, and are currently referred to as informal Eburneus
Group. The common characters, admittedly polythetic, for the Eburneus
Group, are: irregularly bulging tubers, presence of corky outer tuber skin,
turgid petioles, at least upper male flowers vertically aligned, inflorescence
with a fishy smell at anthesis, and large (to 2 cm long) elongate fruits that,
except for those of A. titanum (Becc.) Becc. (5-6 cm long), are the largest in
the genus.
The systematic position of non-limestone A. infundibuliformis
is unclear. The leaf, especially the intricate morphology of the petiole
ornamentation, is quite different to the turgid, smooth, usually unmarked
light green, rarely with smooth paler green or reddish circular markings
typical of the Eburneus Group. The tuber is also markedly different and
striking by the inside flesh deep red.
The use of an informal subordinate grouping is in line with the approach
used in other taxonomically intractable groups (e.g., Alocasia G.Don.,
Schismatoglottis Zoll. & Moritzi, the Potheae Engl., and Rhaphidophora
Hassk.), where the establishment of informal groups has become a standard

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A Review of the White-flowered Amorphophallus Species in Sarawak
approach until such time as phylogenetic testing can be undertaken leading
to the establishment of evolutionarily robust groups (see Boyce and Wong,
2008 for commentary on this approach). Other species in the Eburneus
Group are A. julaihii (Mulu), A. hottae Bogner & Hett., and A. palawanensis
Bogner & Hett. in the Philippines (Palawan). All except A. hottae are
limestone obligates.
Key to the white-flowered Amorphophallus species in Sarawak
1. Petioles turgid, smooth, rachises of fully developed leaf spreading.
Spadix appendix smooth, rugulose or echinate but never with hooked
staminodes. Plants of limestone .................................................................. 2
1. Petioles not turgid, conspicuously white-warty, rachises of fully developed
leaf ascending. Spadix appendix with conspicuous hooked staminodes.
Plants of a variety of substrates but never on limestone ................................
..................................................................................... 3. A. infundibuliformis
2. Spadix appendix echinate. Male flowers not fused into longitudi nal rows.
Spathe limb reflexing during anthesis. C and N.E. Sarawak ........................ 3
2. Spadix appendix smooth or weakly rugulose. Male flowers fused into
longitudi nal rows. Spathe limb remaining erect throughout anthesis. S.W.
Sarawak .......................................................................................................... 4
3. Petioles dull pale red with strongly demarcated irregular reddish brown
spots and elongated streaks. Opening of lower part of spathe strongly
recurving to form a conspicuous collar ca 1cm wide during anthesis, spathe
limb margins recurving markedly. Spadix appendix stongly echinate.
Merirai .......................................................................................... 4. A. juliae
3. Petioles pale to medium green, concolorous or very occasionally with
obscure paler green circles. Opening lower part of spathe not or only
minutely recurved, spathe limb incurved or planate, margins not recurving.
Gua Niah ................................................................................ 5. A. niahensis
4. Petiole to 120 cm, long relative to the lamina diameter; lamina little divided,
leaflets to 60 cm long, never petiolulate; cataphylls greyish brown. Ovaries
densely congested, dark purple, stigma diameter equalling ovary. Padawan
limestones ............................................................................. 2. A. eburneus
4. Petiole to 50 cm, very short relative to the lamina diameter; lamina much
divided, leaflets to 35 cm long, terminal leaflets petiolulate; cataphylls off
white. Ovaries distant, pale purple, stigma diameter distinctly smaller
than ovary. Bau limestones .......................................... 1. A. brachyphyllus

252 Gard. Bull. Singapore 61 (2) 2010
1. Amorphophallus brachyphyllus Hett., Blumea 46(2): 258 (2001). – Type:
Malaysia, Sarawak, Kuching, Division, Bau district, exact locality unknown,
(described from plant cultivated in Hortus Botanicus, Leiden); orig. coll. P.
Kessler EVK 246 sub. Hetterscheid H.AM.032C-T (holo, L, spirit coll.). Fig.
1.
Medium-sized, robust aseasonally dormant geophytic herb to 90 cm. Tuber
depressed globose, not offsetting, with irregular raised areas, to 32 cm diam.
×15 cm high, surface with a grey, corky layer. Leaf solitary; petiole short, to
50 × 5 cm diam., uniformly green, very turgid; lamina to 188 cm diam., highly
dissected, rachises naked; leaflets elliptic-lanceolate, to 35 ×11 cm, those on
the most proximal parts of the rachises petiolulate, upper surface mid-green,
slightly glossy or dull, slightly coriaceous. Inflorescence solitary, rarely two
together, short pedunculate; cataphylls off-white; peduncle 8-13 ×1- 2.2 cm
diam., entirely subterranean, white with a faint greenish flush, smooth, very
tightly enveloped by the cataphylls; spathe erect, suborbicular, often broader
than long, 10-13.5 ×11.5-16 cm diam., limb obliquely spreading at female
anthesis, erect at male anthe sis, lower part tubular, strongly convolute, largely
hidden in cataphylls, spathe exterior off-white, occasionally flushed pale reddish
purple on the inside limb margins, interior with base reddish purple, and with
scattered small warts, or coarsely grooved, with grooves dis tinctly verruculate.
Spadix longer than spathe, stipitate, 13.5-21 cm long; stipe massive, oblique, off-
white, 0.6-1 × 1.6 cm diam. (base); female flower zone 1.5-2.5 cm ×1.5-2.3 cm
diam., sligh tly conic, flowers in vertically separate sinuous chains; male flower
zone conic, 3-4.5 × 1.1-2.2 cm diam., flowers arranged as female flowers but
chains closer together, or partly or entirely fused vertically, sometimes forming
vertical chains; appendix fusiform, 8-14 × 1.2-2.8 cm diam., slightly laterally
compressed, subacute, yellowish white, surface rug ulose and with narrow,
shallow grooves, producing a strong smell of fried fish and oozing out droplets
at female anthesis. Pistil (female flower) with an ovate or slightly depressed
ovary, 2-3 mm diam. × 2.5-3 mm high, base off-white, top dirty reddish brown,
unilocular, one basal ovule; style excentrically placed, consisting of three acute
branches, two acroscopic small ones and one basiscopic longer one, pale dirty
reddish brown, ca 1.5 mm diam. × 0.3-0.8 mm long; stigma thin, ca 1.5 mm
diam. × ca 0.5 mm high, irregularly, shallowly lobed-sinu soid, surface very
pale dirty brow nish, verruculate. Male flo wer consisting of ca 3 stamens but
pattern often obscured by lateral and vertical fusion of flowers; stamens ca 1
mm high, × ca 1-2 mm diam., often fused with adja cent stamens; filaments ca
0.5 mm long, entirely connate; anthers ca 0.5 mm long, truncate, often entirely
connate, ivory-white; pores apical, rounded, oval or variously elonga te, often
confluent with adjacent pores in various ways. Fruit a very large, elongate,
slightly angulate berry, up to 4 × 2 cm, ripening red, 1-seeded. Seeds elongate-

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A Review of the White-flowered Amorphophallus Species in Sarawak
Figure 1. Amorphophallus brachyphyllus Hett. A. Flowering plant in habitat, note the erect
spathe limb and rugulose spadix appendix; B. Inflorescence with spathe artificially opened.
Note the scattered pistils, and the male flowers fused into longitudinal rows; C. Mature
leaf. Note the complex lamina division and the distal-most leaflets are petiolate; D. Newly
emerging leaf. Note the unmarked, turgid petiole; E. Mature infructescence. [Images: A, C-E
© Peter Boyce. Image B © W.L.A. Hetterscheid].

254 Gard. Bull. Singapore 61 (2) 2010
oblongo-conical, ca 3 cm × 1.2 cm diam. at the point of germination, 0.7 at the
opposite end, skin brownish.
Distribution: East Malaysia, Sarawak, endemic to Karst limestone formations
in the Bau area of Kuching Division.
Ecology: On rocky lowland forested limestone slopes under perhumid to
everwet evergreen forest, in humus layer or humus-filled pockets, less often in
clay at the base of limestone formations, 15-60 m asl.
Notes: Amorphophallus brachyphyllus is without doubt closely related to A.
eburneus and the inflorescences are deceptively similar, although separable
by these characters: stigma of A. brachyphyllus is half the size of that of
A. eburneus, while the pistils are much more regularly placed and more
congested in A. eburneus. In addition to these small but consistent differences
there is a marked difference in leaf morphology. In A. eburneus the leaf
has a long petiole (to 120 cm) relative to the lamina diameter (the reverse
in A. brachyphyllus). Moreover, the lamina in A. eburneus is considerably
less strongly divided, with the leaflets distinctly larger (to 60 cm) and
never petiolulate. Cataphylls in A. eburneus are greyish brown, those in A.
brachyphyllus off-white. These vegetative differences remain constant, and
coupled with geographical separation, and differences in the inflorescence,
strongly support the recognition of two discrete but closely related, probably
vicariant, taxa. Amorphophallus niahensis, described elsewhere in this paper
is also in this complex, as too is A. juliae.
Etymology: The epithet brachyphyllus (Greek: brachy - short; phyllus - leaf)
refers to the very short petiole length relative to the diameter of the lamina.
Other specimens seen: MALAYSIA. Sarawak. Kuching Division: Bau, Gua
Angin, 5 Jun 1999, C.C. Lee AM-21.1 (SAR); Bau, Jambusan, 26 May 2004, P. C .
Boyce & Jeland ak Kisai AM-31 (SAR); Bau, Gunung Bidi, 01° 23’ 27.0”; 110°
07’ 07.6”, 7 Dec 2004, P.C. Boyce & L.Jenkins AM-88 (SAR); Bau, without
further locality data: Hetterscheid H.AM.031A (L).
2. Amorphophallus eburneus Bogner, Willdenowia 18: 441 (1989). – Type:
Malaysia, Sarawak, ‘near Padawong, north of Bau’ (see notes below), Bogner
1772 [described from plant cultivated in Munich Botanical Garden; orig.
coll. York Meredith s.n. sub. Bogner 1772 (holo, M)]. Fig. 2.
Medium-sized to large, robust, aseasonally dormant geophytic herb to 1.3
m. Tuber depressed-globose, not offsetting, to ca 35 cm diam. × ca 20 cm high,

255
A Review of the White-flowered Amorphophallus Species in Sarawak
Figure 2. Amorphophallus eburneus Bogner. A. Flowering plant in habitat, note the erect
spathe limb and rugulose spadix appendix; B. Inflorescence with spathe artificially opened.
Note the scattered pistils, and the male flowers fused into longitudinal rows; C. Mature leaf.
Note the simple lamina division and no leaflets are not petiolate; D. Mature leaf, infructescence
and seedling. Note the unmarked, turgid petiole; E. Mature infructescence. [Images A-C & E
© Peter Boyce. Image D © Art Vogel (used with permission)].

256 Gard. Bull. Singapore 61 (2) 2010
pale greyish brown, skin corky, broken up in numerous, small, angulate fields
separated by narrow grooves. Leaf solitary; petiole very turgid, to ca 120 × ca
10 cm diam., smo oth, uniformly pale green or occasionally with a few scat tered
whitish greenish spots; lamina moderately dissected, up to ca 240 cm, diam.,
rhachises winged distally from the basal bran ches; leaflets elliptic or elliptic-
lanceolate, 12-60 cm long, 5.5-21 cm diam., mid or pale green, coriaceous,
long acuminate. Inflorescence solitary, short pedunculate, largely hidden in
cataphylls; cataphylls ca 6, lanceolate, pale olive brown to whitish or greenish
with pale brownish flushes, largest up to c a 35 ×10 cm; peduncle 15-20 × c a 2.5 cm
diam., pale green, entirely hidden by catap hylls; spathe erect, infundibuliform,
ovate, base strongly convolute and hidden by cataphylls, separated from limb
by a shallow constriction, limb slightly spreading, acute, margins revolu te, 20-
23 × 19-21 cm, outside creamy white, upper margins sometimes flushed with
purple, inside base dark purple and then cream, limb cream with or without a
pale purple flush, base within with numerous irregu lar, shal low warts and some
shallow grooves. Spadix slightly longer than spathe, shortly stipitate, 21-26 cm
long; female flower zone slightly conic, 2.5-3 × 2-2.5 cm diam., flowers slightly
or variably distant; male flower zone cylindric, 4-5 × 1.5-2 cm diam., flowers
congested; appendix 14-18 × 1.5-3 cm diam., terete or laterally com pressed,
acute, cream, turning pale yellowish during male anthesis, surface rugulose and
with scattered, short, shallow grooves, producing a smell of fish during female
and male anthesis. Pistil (female flower) comprised of a depressed pyriform
or oblong ovary, 2.5-4 diam.× ca 4-5 mm high, uni- or rarely (?) bilocular, top
divided in three narrow lobes, base white or pale green, remainder dark purple;
stigma thin, strongly sinuous, stella te, + 2-lobed, partly sunken in be tween the
three lobes emana ting from the ovary, surface dense ly scaberulate, dirty grey-
ish stained with purple, ca 1.5-2.5 diam. × ca 0.5-1 mm high, + quadrangu lar in
cross-secti on. Male flower consisting of 4-6 stamens, often elon gate parallel to
the spadix-axis and connate with upper and/or lower flowers; stamens ca 1 mm
long × ca 1-2 mm diam.; filaments ca 0.5 mm long, conna te; anthers ca 0.5 mm
long, free or connate, truncate or subtruncate, pores apical, free or con nected
within one flower or with other flowers and then irre gularly elongate. Fruit a
berry, very large, elongate, slightly angulate, 4.5 × 2 cm, red, 1-seeded. Seeds
elongate conical, 3.5 cm long × 1.2 cm diam. at the point of germination, 0.7 at
the opposite end, testa brownish.
Distribution: East Malaysia, Sarawak, endemic to Karst limestone formations
of Padawan (Kuching Division) and Tebedu (Samarahan Division).
Ecology: Perhumid lowland forested limestone, growing deep in limestone
cracks with leaf litter 25- 350 m asl.

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A Review of the White-flowered Amorphophallus Species in Sarawak
Notes: There are two errors in the type locality cited by Bogner (1989).
Padawan (Padawong, sic) is southeast, not north, of Bau. The limestones of
the Padawan area are both geographically and floristically distinct from the
Bau limestones and extend down to the Kalimantan border in the direction
of Tebedu and Serian (Samarahan Division), with their northern boundary
to the east of the Bungo range. Amorphophallus eburneus is restricted to
these limestones. For differences between A. eburneus and A. brachyphyllus
see under that species.
Etymology: The epithet eburneus (Latin: ivory white) is in allusion to the
white spathe and spadix.
Other specimens seen: MALAYSIA. Sarawak. Kuching Division: Padawan,
Gunung Braang, 2 May 2001, C.C. Lee AM-67.1, AM-67.2 (SAR); Padawan,
Bukit Manok, 01° 12’; 110° 18’, 18 Mar 2004, P.C. Boyce AM-67.3 (SAR);
Padawan, Vogel 940011 (L, cult. in Hortus Botanicus, Leiden, sub. Hetterscheid
H.AM.402); Vogel 940012 (L, cult. Hortus Botanicus, Leiden, sub. Hetterscheid
H.AM.394); Vogel 970618 (L, cult. Hortus Botanicus, Leiden, sub. Hetterscheid
H.AM.893); Padawan, Gunung Penrissen, Vogel s.n. (L, cult. Hortus Botanicus,
Leiden, sub. Hetterscheid H.AM.311). Samarahan Division: Serian, Pichin,
Umon Murut, Tiab Belanting, 01° 08’ 03.7”; 110° 27’ 00.3”, 15 Jun 2005, P.C.
Boyce s.n. (image record SAR); Serian, Mongkos, Kampung Batuh, Gunung
Selabur, 00°57’ 26.2”; 110° 30’ 15.8”, 15 Mar 2006, P.C. Boyce s.n. (image
record SAR);
3. Amorphophallus infundibuliformis Hett., A.Dearden & A.Vogel, Blumea
39(1-2): 259 (1994). – Type: Malaysi a, Sarawak, Kuching Divisi on, without
further locality, 1990, Dearden s.n. (holo, L). Fig. 3.
Medium-sized, slender, aseasonally dormant geophytic herb to 1.3 m. Tuber
depressed-globose to subglobose, pinkish externally, internally deep red,
without offset development. Leaf solitary; petiole, pale grey-green to dark
green to dark green-purple, with dirty whitish with numerous, confluent,
irregular, green spots and scattered white puncti form dots and patches, these
more or less raised; lamina weakly dissected, up to 35 cm diam., thinly
coriaceous, adaxial surface deep, sometimes weakly metallic, glossy green,
abaxial surface paler, rachises naked, ascending, very shallowly and narrowly
canaliculate, greyish-green with irregular dark green patches; leaflets
lance olate, margin with numerous small undulations, main veins impressed,
2-11 × 2-5 cm, shortly petiolulate, petiolule 0.2-1 mm long, very slightly
canaliculate adaxially, lowermost pair of leaflets symmetrical, all others
asymmetrical and obliquely inserted on petiolule, apex shortly acuminate to

258 Gard. Bull. Singapore 61 (2) 2010
Figure 3. Amorphophallus infundibuliformis Hett., A.Dearden & A.Vogel. A. Flowering
plant in habitat, note the funnel-form erect spathe; B. Inflorescence with spathe artificially
opened. Note hooked staminodes covering much of the spadix appendix; C. Detail of petiole
to show the diagnostic raised white warts; D. Mature leaf. Note ascending rachises; E. Mature
infructescence. [Images A-E © Peter Boyce].

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A Review of the White-flowered Amorphophallus Species in Sarawak
long acuminate, up to 1.5 long; margins of larger leaflets very slightly sinuate;
5-8 pairs of primary lateral veins, venation forming distinct submarginal
veins; interprimary veins much less defined, secondary veins forming a
weak reticulum. Inflorescence solitary, short pedunculate; cataphylls whitish
with nume rous small, pinkish dots and many larger, blackish green, irregular
spots; peduncle 4 cm × ca 0.8 cm diam. (base), lengthening in fruit; spathe
strongly convolute, funnel-form, obconic in side-view, transversely orbicular-
elliptic, 6 × ca 8 cm diam., very widely acute, limb and base poorly differen-
tia ted, outside dirty whitish with pale brownish venation and scattered, small,
angulate, blackish green spots, inside whitish, the lower half dark maroon, base
within strongly, longitudinally ridged. Spadix sessile, very obliquely inserted,
slightly longer than spathe; female flower zone oblique, annuliform, 1 mm
(dorsal side)-5 mm (ventral side) long × ca 1 cm diam., flowers conge sted;
male flower zone cylin dric, base oblique, 0.8-1.3 cm ca 1 cm × diam., flowers
congested; appendix cylin dric, obtuse, whitish, 6.5 × 1 cm diam., enti rely or
at least almost entirely, densely covered with hooked stamino des, these in
the lower third shortly conical to aristate, some times uncinate and with long,
narrowly decur rent, ridge-like bases, upwards shorter or reduced to only the
base, up to 2 mm long, bases longitudinally confluent. Pistil (female flower)
with ovaries depressed, irregular or cubic, angulate in cross-secti on, 0.9-1.5
× 1.2-1.5 mm, reddish brown, near the style insertion maroon, unilocu lar;
style absent or only basiscopically developed; stigma sessile or partly sessi-
le, acroscopically orientated, reniform, a shallow depression in the midd le,
one conic lobe on the out ward facing margin, 0.8-1 mm × 0.3-0.5 mm high,
dark greyish brown, surface densely verruculate. Male flower upwards fused
into longitudi nal chains, otherwise consisting of 3-5 stamens, upper flowers
confluent with the lowermost staminodial ridges; stamens ca 1-1.3 × ca 0.7
mm long, roun ded, oval or irregu lar in cross-section, white; filaments absent or
nearly so, entirely conna te; anthers truncate; pores apical, rounded or elongate
(con fluent). Infructescence with few to rather many berries, irregular; berries
elongate, ca 2 × 0.75 cm, slightly conic, top truncate, orange-red, one-see ded.
Seed elongate ellipsoid, ca 1.8 × 0.5 cm, testa pale brown.
Distribution: East Malaysia, Sarawak (Kuching, Sri Aman & Kapit Divisions
but probably throughout the state and overlooked); Indonesia, Kalimantan
Barat.
Ecology: Perhumid to everwet lowland mixed dipterocarp to upper hill forest,
mainly on sandstones, occasionally on shale, rarely on raised podzols, 50-875
m asl.
Notes: Amorphophallus infundibuliformis cannot be mistaken for any other

260 Gard. Bull. Singapore 61 (2) 2010
species in the genus in Sarawak by virtue of the spadix appendix with hooked
staminodes. The petiole, with ascending rachices and intricately ornamented
with dark patches and conspicuous raised, white warty areas is approached
by that of A. ranchanensis, in which the raised areas are scutteliform and pale
grey-green. The inflorescences of A. infundibuliformis and A. ranchanensis
are profoundly dissimilar.
Etymology: The specific epithet is from the Latin for funnel-shaped, referring
to the shape of the spathe.
Other specimens seen: MALAYSIA. Sarawak: Kuching Division: Lundu,
Gunung Gading, 01° 42'; 109° 50', 3 Mar 2004, P.C. Boyce & Jeland ak Kisai
AM-3 (SAR); Bau, Segong, Sungai Adis, 11 Mar 2004, P.C. Boyce & Jeland
ak Kisai AM-4.1(SAR); Bau, Kampung Jugan, 26 Mar 2004, P.C. Boyce &
Jeland ak Kisai AM-4.2 (SAR); 22 May 2004, P.C. Boyce, Jeland ak Kisai
& Jipom ak Tisai AM-33 (SAR); Padawan, Puncak Borneo, trail behind
Malesiana Tropicals Nursery to Hornbill Resort golf course maintenance
kampong, 01° 07' 35.1"; 110° 13’ 28.8”, 10 Jun 2004, P.C. Boyce & Jeland ak
Kisai AM-36 (SAR); 01° 07' 35.1"; 110° 13' 28.8", 30 Nov 2004, P.C. Boyce
AM-87 (SAR); Sematan, Teluk Selabang Ulu Sungai, Selabang, 8 Oct 2004,
P.C. Boyce & Jipom ak Tisai AM-81 (SAR); Bau, Gunung Noka, 11 Oct
2004, P.C. Boyce & Jeland ak Kisai AM-84 (SAR); Lundu, Brungea, 8 Jan
2005, P.C.Boyce & Jipom ak Tisai AM- 92 (SAR); Bau, Kampung Duyoh,
Sungai Duyoh, 01° 20' 45.6"; 110° 02' 36.9", 8 Jun 2005, P.C. Boyce & Jeland
ak Kisai AM- 95 (SAR); Matang, Kubah N.P., Waterfall Trail, 7 Mar 2009,
P.C. Boyce (SAR, image record). Sri Aman Division: Lubok Antu, Batang
Ai, Nanga Sumpa, 01° 12' 02.3"; 112° 03' 09.3", 27 Jul 2004, P.C.Boyce, Jeland
ak Kisai & N.Lembang AM-43 (SAR); Lubok Antu Batang Ai, Nanga
Sumpa, Sungai Pedali, 01° 11' 58.9"; 112° 03' 27.0", 7 Apr 2005, P.C. Boyce
et al. AM-94 (SAR); Sri Aman, Lubok Antu, Batang Ai, Nanga Sumpa,
Wong Ensalai, 01° 11' 51.0"; 112° 03' 39.9", 26 May 2008, P.C. Boyce, Wong
Sin Yeng & Jipom ak Tisai AM-200 (SAR). Kapit Division: Kapit, Taman
Rekreasi Sebabai, 01° 56' 45.6"; 112° 54' 16.8", 13 Dec 2004, P.C. Boyce,
Jeland ak Kisai & M. Gibernau AM-89 (SAR). INDONESIA. Kalimantan:
Kalimantan Barat, Semeng, Sizemore 960031 (L, image record).
4. Amorphophallus juliae P.C. Boyce & Hett., sp. nov.
Ab omnibus speciebus in habitu calcicola lithophytica Borneensibus borealis
combinatio appendice spadicis echinatis et petiolorum foliis pallide rubro
et valde brunneis maculatis distinguitur; ab A. niahensis spathae lamina
marginem valde revolutis et reflexis et appendice spadicis profunde echinatis
differt. – Type: Sarawak, Kapit Division, Belaga District, Bukit Merirai, path

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A Review of the White-flowered Amorphophallus Species in Sarawak
to Gua Tiang & Gua Spring, 2° 46' 07" N; 113° 38' 58" E, 6 Jul 2005, P. Leong,
R. Kiew, S. Julia et al. PL 135 (Holotypus, SAR; isotypus, SING.). Fig. 4.
Medium-sized, moderately robust, aseasonally dormant geophytic herb to
1.2 m tall. Tuber depressed globose, with irregular slightly raised areas, up
to 7 cm diam., 4 cm high, surface pale brown, interior white. Leaf solitary,
petiole proportionately short compared to the lamina diameter; petiole up to
35 cm long, ca 2 cm diameter at base, moderately turgid, cylindrical, smooth,
uniform dull pale red with strongly demarcated irregular reddish brown
spots and elongated streaks, subtended by 2-3 marcescent cataphylls, these
extending ca 1/3rd the length of the petiole; lamina moderately dissected,
up to 55 cm diam., thinly coriaceous, adaxial surface mid green, abaxial
surface paler, rachises naked, narrowly canaliculate, pale pinkish green;
leaflets elliptic-lanceolate, 2-13 × 2-5 cm, more-or-less sessile, lowermost
pair of leaflets symmetrical, all others asymmetrical and obliquely inserted
or rhachis, apex shortly acuminate to 1.5 long; margins of larger leaflets
very slightly sinuate; 5-7 pairs of primary lateral veins, these adaxially
flush to slightly impressed, abaxially very slightly raised; venation forming
distinct submarginal veins; interprimary veins less defined, secondary veins
forming a weak reticulum. Inflorescence solitary, occasionally two together,
flowering before emergence of foliage leaves but in any one colony mature
plants at all stages of growth (emerging leaves to ripe infructescences)
present simultaneously; peduncle and lower part of spathe encased in sub-
fleshy cataphylls; peduncle cylindrical, up to 13 cm long, 5-6 mm diam., pale
green, pinkish where exposed to light; cataphylls several per inflorescence;
elongate-ovate to linear, 2-15 cm × 1.5 -3.5 cm, pale greenish white, sub
fleshy at anthesis, then soon withering and then decaying, drying mid brown.
Spathe broadly oblong-ovate, funnel-form, up to 9 cm long × 3 cm wide
(fresh), pressed material up to 7 cm diam.; spathe limb accounting for ca
1/3 or less of the spathe length, margins recurved at anthesis and at first
somewhat conspicuously green-veined; interior white, smooth, somewhat
glossy, exterior very pale greenish white to white; lower spathe convolute
and much inflated at anthesis, 2-7 cm long, interior muricate-verrucate,
deep reddish purple, exterior pale greenish white, sometimes slightly pink-
tinged, the margins recurving to form a conspicuous collar ca 1cm wide, this
somewhat glossy and frequently tinged and veined pale green at anthesis.
Spadix exceeding spathe, 9-12 cm long. Appendix up to 11 cm long, slender
elongate-fusiform, ca 9 mm diam. (fresh), ca 4 mm diam, (dried), white to
dull cream, very pronounced-echinate, producing a mild odour of rotten
fish during anthesis. Flowers unisexual; male flower zone weakly fusiform-
cylindrical, up to 3 cm × 6 mm diam., cream; stamens ca 1 mm long, ca
0.5 mm broad across, pores paired, mostly solitary, the reduction in pore

262 Gard. Bull. Singapore 61 (2) 2010
Figure 4. Amorphophallus juliae P.C.Boyce & Hett. A-B. Flowering plants in habitat, note
the strongly echinate spadix appendix, the recurved lower spathe margins and recurved
spathe limb; C. Mature leaf; D. Emerging leaf. Note the conspicuous petiole markings; E.
Mature infructescence. [Images A-C, E © Julia anak Sang (used with permission). Image D
© Peter Boyce].

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A Review of the White-flowered Amorphophallus Species in Sarawak
number proceeding upwards towards the appendix, pollen pale yellow.
Female flower zone cylindrical, contiguous with the maleflower zone, ca 4.5-
7 × ca 7 mm diam.; male flowers dense, not arranged in longitudinal rows;
pistils (female flowers) few, densely arranged, ovaries compressed globose,
ca 1.5 × 1.5 mm, dark purple, mostly bilocular; stigma sessile, conspicuously
three lobed. Infructescence with up to 50 berries, peduncle up to 18 cm long,
but mostly buries, ca 7 mm diam. at base, 9 mm diam. at apex, with a dark
brown V-shaped scar from the marcescent spathe. Fruit an ellipsoid berry
15-21mm × 8-10 mm, apex rounded, with conspicuous impressed blackish
stigma remnants, one seeded, deep orange at maturity. Seeds ellipsoid, 12-17
mm × 7-8.2 mm wide, testa smooth, thin, yellowish green.
Distribution: Endemic to Sarawak, so far recorded only from Bukit Merirai,
Belaga, Kapit Division.
Ecology: Lowland limestone forest, shady areas in humus-filled fissures and
holes in limestone, ca 60 m asl.
Notes: By the leaf with a proportionately short petiole compared with the leaf
lamina diameter, and in bearing numerous small leaflets Amorphophallus
juliae is vegetatively most similar A. brachyphyllus and A. niahensis. From
both, A. juliae differs in the pale reddish petioles with large darker reddish
brown spots (vs pale to medium green, concolorous or very occasionally
with obscure paler green circles in A.brachyphyllus and A. niahensis ).
The male flowers not fused into longitudinal rows, the subentire to
weakly bilobed stigma and echinate spadix appendix resemble those of A .
niahensis, although the echinate texture is markedly more pronounced in
A. juliae. Amorphophallus juliae is readily distinguished from A. niahensis
by the opening of the lower part of spathe strongly recurving to form a
conspicuous collar ca 1cm wide during anthesis (margins not or only
minutely recurved in A. niahensis) and spathe limb margins recurving very
markedly.
Amorphophallus juliae is most readily distinguished from A.
brachyphyllus by the male flowers not fused into longitudinal rows, the densely
arranged pistils, the proportionately shorter spathe limb (comprising ca 1/3
or less of the entire spathe vs ½ or more of entire spathe), and the spathe
limb reflexing at male anthesis (vs. spathe limb erect throughout anthesis),
and subentire to weakly trilobed stigma (versus deeply bi-trilobed).
Etymology: Named for Julia anak Sang, a forest botanist from the Forestry
Research Department, Sarawak Forestry Corporation, Kuching, and co-
collector of the type specimen.

264 Gard. Bull. Singapore 61 (2) 2010
Other specimen seen: MALAYSIA. Sarawak, Bintulu/Kapit Division border,
Belaga District, Bukit Merirai, trail from Sungai Bekuyat to Gua Naga, 11
July 2005, P. Leong, R. Kiew, S. Julia et al. PL 270, (SAR, SING).
5. Amorphophallus niahensis P.C. Boyce & Hett., sp. nov.
Ad A. brachyphyllus spadix appendice echinatis, floribus masculinus nec in
serialis longitudinaliter tectis, stigmate sessile subintegris; spathae anthesin
feminibus reflexis, non erectis; ab A. juliae petiolorum foliis non pallide
rubro et maculatis, spathae lamina marginem nec valde revolutis differt. –
Type: Sarawak, Miri Division, Niah Suai District, Gunung Subis, Gua Niah
N.P., along plank walk to Niah caves, 21 Aug 2002, Julaihi L et al. S 89309
(Holotypus, SAR). Fig. 5.
Medium-sized, rather robust, aseasonally dormant geophytic herb to 1 m tall.
Tuber depressed globose, with irregular raised areas, up to 12 cm diam., 6 cm
high, surface pale brown, interior white. Leaf solitary, petiole proportionately
short compared to the lamina diameter; petiole up to 60 cm long, ca 2.5 cm
diameter at base, moderately turgid, cylindrical, smooth, uniform pale-green
with a few obscure paler spots present in some individuals, subtended by 2-3
marcescent cataphylls, these extending ca 1/10th the length of the petiole;
lamina moderately dissected, up to 1 m diam., thinly coriaceous, adaxial
surface mid-green, abaxial surface paler, rachises naked except for terminal
leaftets long-decurrent, narrowly canaliculate, mid-green; leaflets elliptic-
lanceolate, 2-15 × 1.5-6 cm, terminal-most petiolulate, petiolule 1-2.5 cm
long, narrowly canaliculate adaxially, lowermost pair of leaflets symmetrical,
all others asymmetrical and obliquely inserted on petiolule, apex shortly
acuminate; 3-9 pairs of primary lateral veins, these slightly impressed
adaxially, abaxially slightly raised; venation forming distinct submarginal
veins; interprimary veins less well-defined, secondary veins forming a weak
reticulum. Inflorescence solitary, occasionally two or rarely three together,
flowering before emergence of foliage leaves but in any one colony mature
plants at all stages of growth (emerging leaves to ripe infructescences)
present simultaneously; peduncle and lower part of spathe encased in sub-
fleshy cataphylls, peduncle cylindrical, up to 17 cm long ×5-6 mm diam., pale
green; cataphylls several per inflorescence; elongate-ovate, 3-16 cm × 1-4
cm, pale greenish white, sub fleshy at anthesis, soon withering and decaying,
drying mid brown. Spathe broadly oblong-ovate, narrowly funnel-form, up
to 9 cm long × 3 cm wide (fresh), pressed material up to 5 cm wide; spathe
limb accounting for ca 1/3 or less of the spathe length, spathe mouth margins
hardly recurved at anthesis and spathe limb margins planate; interior white,
smooth, somewhat glossy, exterior very pale greenish white to white; lower
spathe convolute and much inflated at anthesis, 2-7 cm long, interior muricate-

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A Review of the White-flowered Amorphophallus Species in Sarawak
Figure 5. Amorphophallus niahensis P.C.Boyce & Hett. A. Flowering plants in habitat, note
the echinate spadix appendix and recurved spathe limb; B. Inflorescence with spathe artifi-
cially opened. Note the warty lower spathe interior and the male flowers not in fused longi-
tudinal rows; C. Mature infructescence; D. Mature leaf. Note the complex division. [Images
A-D © Peter Boyce].

266 Gard. Bull. Singapore 61 (2) 2010
verrucate, deep reddish purple, exterior pale greenish white, sometimes
slightly pink-tinged. Spadix exceeding spathe, 9-12 cm long. Appendix up to
9 cm long, elongate-fusiform, ca 9 mm diam. (fresh), ca 4 mm diam, (dried),
white, moderately echinate, producing a sharp smell of rotten fish at anthesis.
Flowers unisexual; male flower zone cylindrical, up to 3 cm long, 6 mm diam.,
cream; stamens ca 1 mm long, ca 0.5 mm broad across, pores paired, partially
fused or solitary, pollen dark yellow. Female flower zone shortly cylindrical,
contiguous with the male zone, ca 4.5-7 mm × ca 7 mm diam.; pistils few,
densely arranged; ovaries compressed globose, ca 1.5 × 1.5 mm, dark purple,
mostly bilocular; stigma sessile, three lobed. Infructescence with up to 35
berries, pedunculate up to 22 cm long, 6 mm diam. at base, 9 mm diam. at
apex, with blackish dark brown V-shaped scar from the marcescent spathe,
basally with remains of the cataphylls. Fruit ellipsoid 15-16 × 8-10 mm, apex
rounded, with blackish stigma remnants, when ripe deep orange, one seeded.
Seeds ellipsoid, 12-14 mm × 7-8.2 mm wide, testa smooth, thin, yellowish
green, seed copiously starchy, embryo small.
Distribution: East Malaysia, Sarawak, so far recorded only from Niah
National Park.
Ecology: Limestone forest, growing shady areas in humus-filled fissures and
holes in limestone, often on limestone emergent in swampy areas, ca 45 m
asl.
Notes: Amorphophallus niahensis is most similar to A. brachyphyllus,
especially in the rather short petiole compared to the lamina diameter, but
is readily distinguished by the conspicuously echinate spadix appendix,
the male flowers not arranged in longitudinal lines, the concolourous deep
purple pistils, and the spathe limb reflexing at female anthesis.
Amorphophallus niahensis approaches A. juliae in the echinate
spadix appendix morphology (although the echinate texture is markedly
more pronounced in A. juliae), but is readily distinguished by the pale green
(not pink) petiole lacking any markings (vs reddish-brown spotted) and the
spathe limb margins not or only slightly recurving at anthesis.
Curious to note is that in nature the inflorescences very often produce
two morphologically normal spathes, set at 180° to one another. Similar
observations have been made with A. eburneus and A. brachyphyllus.
Etymology: The species is named for originating from Gua Niah, to which
it is endemic.

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A Review of the White-flowered Amorphophallus Species in Sarawak
Other specimens seen: MALAYSIA. Sarawak, Miri Division: Niah Suai
District, Niah National Park, Gunung Subis, outside Great cave, 24 Apr
1972, J.A.R. Anderson S 31903 (SAR); Niah N.P., trail to Great cave, 03° 49’
09.9”; 113° 46’ 52.3”, 13 Oct 2005, P.C. Boyce, Jeland ak Kisai & Jipom ak
Tisai AM-101 (SAR); Niah Suai District, Niah National Park, Madu Trail,
03°48’ 57.9”; 113° 46’18.3”, 13 Jul 2006, P.C. Boyce et al. AM-107 (SAR);
Subis, Gua Niah N.P., below W mouth of Great cave, 22 Aug 2002, K. Pearce
et al. S 89487 (SAR); Batu Niah. 113 46 E. 3 49 N, Vogel 970616 (L, cult.
Hortus Botanicus, Leiden, sub. Hetterscheid H.AM.895).
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