NEPENTHES BOKORENSIS, A NEW
SPECIES OF NEPENTHACEAE FROMCAMBODIA
François Sockhom MEY
3 rue Frédéric Chopin, 59320 Haubourdin, France.
Email: meyfr@yahoo.fr
SUMMARY
A new species of Nepenthes L. (Nepenthaceae) from southern Cambodia, Nepenthes
bokorensis Mey, is described and illustrated. The relationship between this new
taxon and its putative relatives, N. kampotiana Lecomte, N. smilesii Hemsl. and N.
thorelii Lecomte is also discussed.
Key words: Nepenthes, Cambodia, carnivorous plants, taxonomy.
Cambodia, Laos, Thailand and Vietnam.
This geographic area has not received
thorough treatment in comparison to thebetter known centres of Nepenthes
diversity such as Borneo, Sumatra or,more recently, the Philippines (Clarke,
1997, 2001; Jebb & Cheek, 1997, 2001;
Nerz & Wistuba, 1995; Robinson et al.,2009). In fact, the literature on Indochinese Nepenthaceae is extremely poor
and almost no published research has
been carried out since the late 1890s andthe early 1900s.
The chronology of the Indochinese
species can be summed up as follows:
William B. Hemsley described
N. smilesii Hemsl. from a Thai specimen
in 1895; John M. Macfarlane described
N. anamensis Macfarlane based on aVietnamese type specimen in 1908; in1909 Paul Henri Lecomte named threetaxa: N. geoffrayi Lecomte and N.
kampotiana Lecomte based on Camb-INTRODUCTION
The geographical term Indochina is used
to refer to the south-east Asian countries
located between India and China,
namely Burma, Singapore, Thailand,
Vietnam, Cambodia, Laos and Peninsular Malaysia. The term is often
confused with French Indochina, which
was used, from 1887 onwards, to refer
to Vietnam (formerly the states of
Tonkin, Annam and Cochinchine),
Cambodia and Laos (Brocheux &Hemery, 2001). Thailand itself wasregarded as an independent and uncolonised buffer state between French Indochina (Cambodia, Laos and Vietnam)
and British Indochina (Burma).
In this work, the term Indochina will
exclude Peninsular Malaysia and Singapore, as that region is usually treatedwith Borneo in the Nepenthes literature,
and will focus on the countries of6

regions of Cambodia being one of thebest-known examples.
- Most of the type specimens are comprised of fragmented material, making it
difficult to study the species from thatarea. Further, the location data for certain specimens is incomplete or misleading. For example, N. geoffrayi andN. kampotiana have been recorded from
“Kampot, Cambodia”, but Kampot isboth the name of a southern province
and the name of its principal city.
- Finally, the Indochinese species form agroup of superficially similar species.
To the untrained eye, they all appear toshare identical narrow leaves withclasping leaf bases and reddish lower
pitchers. Their inflorescences are alsosimilar, consisting of a raceme with oneflowered pedicels. Until recently, thedelimitations of these Indochinese
species were completely unknown andmost herbarium specimens from Indochina were often incorrectly labelled as“N. thorelii”, “N. aff. Thorelii”, “N.
anamensis” or were simply left undiagnosed.
In his forthcoming work, Pitcher
Plants of the Old World (2009), Stewart
McPherson will reinstate N. kampotianaand synonymise N. anamensis with N.
smilesii following the interpretation provided to him by M. Cheek (pers.
comm.), an interpretation that is fully
supported by the author of this text (F.
Mey).
During a field trip to southern Cambodia in 2007, a new taxon was observedon Phnom (Mount) Bokor (1080 m).
This plateau is located within the Preah
Monivong National Park (Bokor
National Park), which is located near theodian material, and N. thorelii Lecomtebased on some collections from Vietnam. Benedictus H. Danser synonymised N. smilesii with N. mirabilis
Druce in his revision of the genus
Nepenthes (Danser, 1928).
Since these seminal works, in particular the studies of Lecomte, recorded in
Notulae Systematicae (Lecomte, 1909),
the Indochinese Nepenthes flora seems
to have been almost ignored, and theinterest in Nepenthes raised by the workof Danser (1928), Harms (1936), Kurata(1976), Jebb & Cheek (1997, 2001) and
Clarke (1997, 2001) inspired surprisingly little interest in Indochinese
species.
In their ‘Skeletal revision of Nepenthes’, Mathew Jebb and Martin Cheek
lectotypified the material of N. thorelii,
and synonymised N. kampotiana and N.
geoffrayi with N. anamensis as theherbarium material of the two former
species are comprised of only fragmented collections and detached inflorescences (Jebb & Cheek, 1997). They
also retained N. smilesii as a little known
taxon, indicating that its inclusion with
N. mirabilis would have been premature
without further studies.
The striking lack of study of the Indochinese Nepenthaceae can be explainedby at least three factors:- The history of Indochina has involved
a great deal of internal and international
conflict, and the borders of countries
such as Cambodia, Laos and Vietnam
have been opened relatively recently tovisitors and botanists. While tourists are
now welcome and many areas of natural
wealth are managed for visitors, certain
localities remain perilous, the landmined7

slightly decurrent; longitudinal veins 3
on each side of the midrib in outer quarter of the lamina, pinnate veins arisingobliquely from midrib, midrib 2 mm
wide; tendrils straight, terete, 9-18 cm
long, 2 mm in diameter; Leaves of theclimbing stem as those of rosettes, but
tendrils coiling occasionally, 10-14 cm
long, 2 mm in diameter. Lower pitchers
13-20 by 4-6 cm, ovate in the lower
third, narrowing above, often constricted
below the middle, and cylindrical orslightly infundibular towards pitcher
mouth; two alae 14-15 mm wide run
down ventral exterior surface fromtendril to mouth, fringed with narrowfilaments up to 10-12 mm long; pitcher
mouth oblique, peristome striate, loosely
cylindrical, to 20 mm wide and bulbous,ribs to 8 mm high, spaced to 1 mmapart, occasionally raised to form atriangular point; lid orbicular to broadly
elliptic, to 7 cm long by 6 cm wide, witha cordate base, often vaulted, lower
surface without appendages, crateriform
glands dense and numerous, to 0.5 mm
across along midline, 0.2-0.3 mm
elsewhere, glands sparse near margins;spur 11-12 mm long, simple but
occasionally bifurcated. Upper pitchers
variable, generally to 25 cm by 6 cm,
wholly infundibular, narrowly sotowards base and greatly elongated inlower third, occasionally swollen, forming a faint hip above; alae reduced tonarrow ridges; pitcher mouth oblique;peristome striate, loosely cylindrical, to
17 mm wide, outer margin often slightly
flared, ribs fine, to 0.4 mm high, spaced
to 0.5 mm apart; lid orbicular or broadly
elliptic, base cordate, to 6 cm long by 5
cm wide, often vaulted, margins

town of Kampot, the main city of theeponymous province. The taxon
possesses a combination of obvious,
stable features that serve to distinguish itfrom the other Indochinese species present in Cambodia, N. kampotiana, N.
smilesii, and N. thorelii. This taxon from
Bokor National Park is described as a
new species here.
Nepenthes bokorensis Mey, spec. nov.
– Figures. 1, 2A, 2B
Nepenthes thorelii Lecomte simile,
sed foliis longioris latioris oblongis sessilibus vel subpetiolatis basaliter amplexicaulibus peristomio robusto cylindrico pedicellis interdum 2-floribus differt.
- Typus: Marie Martin 1231 bis (holoP!), southern Cambodia, province of
Kampot, Phnom Bokor, 800 m,
7.xii.1968.
Nepenthes bokorensis is most readily
distinguished from its near relatives by
its robust peristome, significantly
broader leaves, the vaulted, orbicular lid
and its occasionally 2-flowered inflorescences.
Terrestrial climber to 7 m tall. Stem ofrosette and short shoots cylindrical incross section, 7-9 mm diameter. Climbing stem terete to 1 cm diameter, internodes ca. 3 cm long. Leaves of therosettes coriaceous, base attenuate andsessile, sometimes sub-petiolate, lamina
oblong to linear-lanceolate, apex acuteto obtuse, sometimes acuminate, 30-35
by 7-8 cm, clasping the stem by threequarters of its circumference, rarely8

Figure 1. Nepenthes bokorensis Mey. a. climbing stem with upper pitcher ; b. maleinflorescence; c. detail of male inflorescence; d. fruit; e. seed; f. lower surface ofpitcher lid; g. lower pitcher (all from photographs). Drawing by François Mey.
9

brown hairs 0.5-1 mm long covering allparts of plant, but sometimes greatly
reduced leaving foliage almost glabrous.
Colour of living specimens: leaves
green, stem, midrib and tendril yellow,
green, orange or red; pitcher exterior
generally red, brown or purple, with
faint purple blotching or, in upper
pitchers, yellow or pink; interior yellowish-green to creamy white, often
blotched purple; peristome red or purple,
striped with darker bands of same or, in
upper pitchers, yellow to orange striped
red and purple; lid as for pitcher
exterior; tepals brown or red.
Specimens examined:
Nepenthes bokorensis – M. Martin
1231 bis (P!), female plant with flowers,

frequently revolute, no appendages; spur
as for lower pitchers. Male inflorescence a raceme, to c. 100 cm, peduncle
60-70 cm long, rachis 20-30 cm longwith c. 80 flowers borne solitary on
pedicels to 5 mm long, but occasionallyon 2-flowered partial peduncles,
androphore to 2 mm long; tepals
orbicular to elliptic, 2 mm long. Female
inflorescence a raceme, 60-100 cm,
rachis 7-20 cm with 30-80 flowers borne
solitary on pedicels to 9 mm long,occasionally on 2-flowered partial
peduncles, ovary 4 mm tall; tepals
orbicular to elliptic, 4 mm long; fruit
generally 10-25 mm long; seeds fusiform, ca. 50-100 per fruit, c. 7 mm long,light brown. Indumentum of silver or

Figure 2A. Upper pitchers of Nepenthes Bokorensis
10Lo-Thieu, Vietnam: lectotype. Thorel,
1032 (P!), Guia-Toan, Vietnam: syntype.
Nepenthes sp. – Aug. Chevalier 36411(P!), Damrei Mountains, Kampot province, Cambodia.

fruit and lower pitchers, Bokor Hill, 800
m: holotype. Geoffray 324 (P!), upper
pitchers with leaves, Popokvil falls,
Bokor Hill, 960 m. Geoffray 325, 328(P!), lower pitchers with leaves, Popokvil falls, Bokor Hill, 960 m. Middleton& Monyrak 539 (P!), two rosetted
plants, Bokor Hill, 944 m. Vidal 4780
(P!), plant with upper pitchers, Bokor
Hill, altitude unknown.
Nepenthes geoffrayi – Geoffray 84, 85,
87, 88, 91, 92, 93 (P!), Kampot, Cambodia.
Nepenthes kampotiana – Geoffray 89,
90, 191, 362 (P!), Kampot, Cambodia.
Nepenthes smilesii – Charoenphol,
Larsen & Warncke 4623 (P!), Phu
Kradung, Loei, Thailand.
Nepenthes thorelii – Thorel 1032 (P!),

Distribution – Southern Cambodia,
Phnom Bokor (Bokor Hill), from 8001080 m altitude. Herbarium material(Aug. Chevalier 36411 (P!)) suggeststhat N. bokorensis may be present atother locations in the Damrei Mountains(Elephant Range), but further study isrequired to reveal the true extent of its
distribution.
Ecology – N. bokorensis occurs inseasonally wet upland scrub and amidst

Figure 2B. Lower pitchers of Nepenthes bokorensis
11

(BKF) contain specimens mainly from
Bokor Hill (from photographs takenfrom three herbarium specimens of
Nepenthes collected at Bokor Hill
deposited at BKF ([SN 093094, SN
098240, third number is unreadable],
identified as “N. thorelii”), it is obviousthat there are collections of N.
bokorensis in Bangkok, too. However, it
was not possible to detect the collector’sname on the herbarium label from thephotograph alone). These have either
been misidentified as N. thorelii or
simply remained undiagnosed. The
N. bokorensis holotype (M. Martin 1231
bis (P!)) was chosen from the Parismaterial. Additional Paris specimens,such as August Chevalier 36411(P!),
include Nepenthes taxa from different
locations in Cambodia that may fallwithin N. bokorensis.

sparse, stunted, lower montane forest. It
grows mainly in open habitats exposed
to strong or direct sunlight, readily
producing a stem to 7 m long thatscrambles and climbs through surrounding vegetation. Some plants may also
grow in bright areas beneath trees, often
in damp soil covered by Sphagnum.
Plants growing in full sun flower at an
earlier stage of development, frequently
flowering when less than 60 cm tall.
Populations of N. bokorensis on Bokor
Hill grow in sandy soil of pH 4.6(Turnble & Monyrak 589 (P!)) and experience a severe dry season. In particularly exposed locations, N. bokorensis
grows sympatrically with Drosera
peltata Thunb., a well known species oftuberous sundew, which exhibits somemonths of dry dormancy. It is not known
whether N. bokorensis produces atuberous stem or thickened root system
like its close relatives N. kampotiana,
N. smilesii and N. thorelii but seedlings
grown by the author from a seedcollection on Bokor Hill demonstrate adeveloping taproot very similar to thosedeveloped by the aforementioned
species. It seems likely that N.
bokorensis also develops such storage
organs, but additional field observations
are required to ascertain this.

2. Putative relatives. Nepenthes
bokorensis is closely related to N.
kampotiana, N. smilesii and N. thorelii,
but differs from all of these species inthat the leaf is much broader andalso more oblong in shape. The occasional production of 2-flowered partial
peduncles is also unusual in this groupof species. It may also be distinguishedfrom N. kampotiana as the foliage ofthat species is typically glabrous,
whereas in N. bokorensis most parts ofmature plants are usually lined withshort hairs. Nepenthes bokorensis may
be distinguished from N. smilesii by its
pitcher morphology; the pitchers ofN. smilesii are narrow, with a thin
peristome, less colouration and shorter
tendril than those of N. bokorensis,
which are broad and have a character-

Etymology – The specific name refers
to Bokor Hill and Bokor National Park,
from where this species was firstcollected.
Notes –
1. Nepenthes bokorensis has been collected on a number of previous occasions. Herbaria in Paris (P) and Bangkok
12populations of N. bokorensis, particularly those on Bokor Hill, which has
recently been leased by the Cambodian
government for important private development. Therefore, the author considers
N. bokorensis to be potentially vulnerable according to IUCN criteria (IUCN,
2004). The future of N. bokorensis in the
Bokor National Park needs to be monitored and the wider distribution of thisspecies across the highlands of southwestern Cambodia studied further.

istically robust peristome. Nepenthes
bokorensis differs from N. thorelii by
the attachment of the leaf to the stem; inN. bokorensis, the lamina is sessile tosub–petiolate and clasps the stem, only
ever becoming slightly decurrent,
whereas in N. thorelii the lamina isnearly completely amplexicaul andstrongly decurrent. Nepenthes bokorensis may also be distinguished from N.
thorelii by its pitcher morphology: thelower pitchers of N. thorelii are ovate
whereas those of N. bokorensis areovate in the lower third and cylindricalabove. Nepenthes bokorensis is unlikely
to be confused with these three species
in the wild and it is not known to occur
sympatrically with any of them. Therefore, no natural hybrids including
N. bokorensis as a parent species are
known.

5. Pictures of habitat. Photos of N.
bokorensis have been displayed on various online forums since august 2007,
documenting the known forms of thetaxon and its habitat.
-CPUK: http://tinyurl.com/bokorcpuk-Pitcherplants.com: http://tinyurl.com/
bokorppc-FloraNepenthaceae: http://tinyurl.com/
bokorfn

3. Carnivory. Cambodian Nepenthes,
including N. bokorensis, are generally
called “ampuong sramoch” (“antspithole” in the Khmer language) by
Cambodians from the province of
Kampot and from the town of Pursat.
Indeed, observations indicate thatants seem to be the principle prey of
N. bokorensis. On the herbarium label ofMiddleton & Monyrak 589 (P!), thecollectors noted that the fluid of thepitchers has a pH of 2.7.

To read a detailed field report on
N. bokorensis by the author, visit thewebsite:http://www.nepenthesofthailand.com/
bokor.htm
ACKNOWLEDGEMENTSFirst and foremost, I thank my wife,
Elisabeth, and my kids, Lucie-Ly, Aliceand Ulysse for their never-ending
support throughout all the stages of thiswork.
It is no exaggeration to state that thiswork never would have seen the light of
day if it were not for the unstinting
support and encouragement of Andreas
Fleischmann. Thank you for your

4. Conservation. In spite of widespread deforestation across much of
Cambodia, the habitat of N. bokorensis
in Bokor National Park has remained
relatively pristine. Unfortunately, theexpanding tourism industry in Cambodia
is now threatening the most accessible
13

advice, the corrections and the Latin
diagnosis.
I am deeply grateful to Dr Alastair
Robinson for editing the text, for his
selfless assistance and encouragement,
and to Greg Bourke for trusting both me
personally and my work.
I would also like to specifically thank
Tom Kahl for providing scarce Indochi-

nese Nepenthaceae literature. Thanks arealso due to the Paris herbarium staff, andin particular to Dr Sovanmoly Hul, forallowing me to examine their collectionof Nepenthes.
My last special thanks will go to mylone wolf friend: I could never havemade it without you – Thank you very
much.

14

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Catalano, M. (2004-2008). http://www.nepenthesofthailand.com/
Clarke, C. M. (1998). “Nepenthes of Borneo”. Natural History Publications(Borneo), Kota Kinabalu. Xii + 207 pp. Reprinted 2007.
Clarke, C. M. (2001). “Nepenthes of Sumatra and Peninsular Malaysia”. Natural
Publications (Borneo), Kota Kinabalu. X + 326 pp.
Danser, B. H. (1931). “The Nepenthaceae of the Netherlands Indies”, Bull. Jard. Bot.
Buitenz. Ser. 3, 9 (3-4): 249 -438. Reprinted 2006 with an Introduction by Dr
Charles Clarke by Natural History Publications (Borneo), Kota kinabalu. Vi +206 pp.
Harms, H. A. (1936). “Nepenthaceae”, in: A. De Candolle, Prodromus systematis
universalis regni vegetabilis, 17: 90-105.
Hemsley, W. B. (1895). “Nepenthes smilesii (Nepenthaceae)”, Kew Bulletin: 116.
IUCN. 2001. IUCN Red List Categories and Criteria: Version 3.1 IUCN Species
Survival Commission. IUCN, Gland, Switzerland and Cambridge, UK.
Jebb, M. & M. Cheek. (1997). “A skeletal revision of Nepenthes (Nepenthaceae)”,
Blumea 42:1-106.
Jebb, M. & M. Cheek. (2001) “Nepenthaceae” Flora Malesiana, Series I, Volume
15: 1-157.
Kurata, S. (1976). “Nepenthes of Mount Kinabalu”. Sabah National Park Trustees,
Kota Kinabalu, Sabah. 80 pp.
Lecomte, P. H. (1909). Notulae Systematicae: 59-65.
Macfarlane, J.M. (1908). “Nepenthaceae” In: A. Engler, Das Pflanzenreich: 39-40.
Robinson, A.S., A.S. Fleischmann, S.R. McPherson, V.B. Heinrich, E.P. Gironella &C.Q. Peña 2009. “A spectacular new species of Nepenthes L. (Nepenthaceae)
pitcher plant from central Palawan, Philippines” Botanical Journal of theLinnean Society 159(2): 195–202.

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