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This paper reviews the species of Nepenthes that occur on limestone (Calcium Carbonate, Ca CO3) both facultative (only sometimes found on limestone) and obligate (restricted to) calcicoles. The greatest number of calcicole Nepenthes are recorded from Borneo, followed by New Guinea, and then Thailand and Philippines. Obligate calcicole Nepenthes species have not yet been recorded from Sumatra, peninsular Malaysia, or other islands which host Nepenthes. The pattern of distribution and the ecological advantages and disadvantages of being a Nepenthes calcicole are discussed.
During a visit to study Nepenthes in Indonesian New Guinea in June 2017,
a new species to science came to light that was published in early 2018
(Cheek et al. 2018). Formerly confused with N. insignis Danser, it is confined
to limestone on the island of Biak off the north coast of New Guinea, and
consequently was named as Nepenthes biak Jebb & Cheek (Figs. 1 & 2).
Martin Cheek
Royal Botanic Gardens, Kew, TW9 3AE, U.K.
Michal R. Golos
School of Biological Sciences, University of Bristol, 24 Tyndall Avenue,
Bristol, BS8 1TQ, U.K.
Fig 1: The original line-drawing of Nepenthes biak from Cheek et al. (2018)
Limestone, being mostly pure calcium carbonate, and so highly alkaline, is
such a challenge for plant species that most do not thrive growing directly on
it. This is partly because salts and minerals, including iron and manganese,
are available only with difficulty due to the alkaline pH. Limestone is a
free-draining substrate, so in seasonal climates is more prone to drought
conditions than normal substrates. This can also pose a physiological
challenge for many plant species, so such substrates tend to have sparser
and shorter woody growth than neighbouring non-limestone areas. Most
plant species avoid limestone and so are known as calcifuges. But some
plant species are adapted to it and have evolved mechanisms for mineral
uptake on limestone. Plants that grow on limestone are known as calcicoles
and can be classified into two groups: facultative calcicoles are species which
can grow either on or off limestone, while obligate calcicoles are restricted
to limestone. Obligate calcicoles occur in many unrelated plant groups.
Several species of Pinguicula, for example, such as Pinguicula vallisneriifolia
Webb, are obligate calcicoles, entirely restricted to limestone. There are
advantages to species being able to grow on limestone: competition from
other plant species in such habitats is much lower, because most plant
species cannot survive or thrive on it. On the downside, obligate calcicoles
are restricted to limestone outcrops and cannot grow anywhere else. If
limestone areas are remote from each other, calcicole species may not be
able to spread to new sites. This has resulted in many calcicoles being
restricted to individual or closely neighbouring limestone patches.
In the Flora Malesiana account of Nepenthes (Cheek & Jebb 2001: 3), it
is remarked that obligate limestone species are only known from Borneo:
Nepenthes boschiana Korth. (now known also to occur on ultramafic
substrate; Lee 2004), N. campanulata Sh.Kurata, N. faizaliana J.H.Adam
& Wilcock, N. mapuluensis J.H.Adam & Wilcock and N. northiana Hook.f.,
and that facultative limestone species are N. reinwardtiana Miq. and N.
albomarginata T.Lobb ex Lindl. (recorded on limestone in Borneo only). It
was considered strange that no Nepenthes had been reported from the
limestone outcrops of the Philippines, Sumatra or of New Guinea, possibly
due to under collecting.
Limestone areas are scattered throughout SE Asia, a legacy of its geological
origins: many of the islands are uplifted from the sea floor and so have
surfaces of accreted coral (i.e. limestone). Additional facultative limestone
species have been reported from Borneo by Lee (2004): N. ampullaria Jack,
N. gracilis Korth., N. lowii Hook.f., N. mirabilis (Lour.) Druce, N. stenophylla
Mast., N. tentactulata Hook.f., N. veitchii Hook.f., and N. vogelii Schuit. &
de Vogel. Additionally, N. epiphytica A.S.Rob., Nerz & Wistuba (Robinson et
al. 2011) has been described from two limestone peaks in eastern Borneo,
Fig 2: Photo of live Nepenthes biak from the Tropical Nursery, Kew. Photo by M. Cheek.
but from what little is known it appears to be strictly epiphytic.
In the last two decades, additional limestone species have come to light
from two areas outside Borneo:
The area of Peninsular Thailand just north of the border with Malaysia,
where several N–S ridges of limestone occur has yielded a trio of new
calcicoles. The first of these limestone Nepenthes to be published was
Nepenthes thai Cheek (Cheek & Jebb 2009), followed by Nepenthes rosea
M.Catal. & Kruetr. (Catalano 2014) and most recently Nepenthes krabiensis
Nuanlaong, Onsanit, Chusangrach & Suraninpong (Nuanlaong et al. 2016).
These are the first records of calcicoles in the Montanae section or species
group which extends from Java, through Sumatra and the Malay Peninsula.
Further south and east in the Raja Ampat islands, Biak and neighbouring
West Papua of Indonesian New Guinea, Nepenthes treubiana Warb.,
discovered over a century ago, has been found to be a limestone species.
It is not unusual as in this species, that in the initial description, substrate
is not mentioned. Nepenthes biak is the second calcicole described from
western New Guinea, but at least one other undescribed species exists
on limestone in the Raja Ampats (Cheek et al. 2018). Both these species
belong in the Insignes (Nepenthes ventricosa Blanco) group, previously
thought to be entirely restricted to the Philippines apart from N. insignis
Danser itself. Again, these records are the first time that calcicole species
have been recorded in that group.
The absence of calcicole species from Sumatra is not surprising since most
of the limestone in that island occurs in the north, where the climate is more
seasonal and so Nepenthes diversity is very low. More surprising is the
near absence of such species from the Philippines, where despite many
new discoveries, only two limestone records are known to us. One of these
is Nepenthes viridis Micheler, Gronem., Wistuba, Marwinski, W.Suarez &
V.B.Amoroso (Micheler et al. 2013) from the Alatae, the largest and most
widespread of the Philippine species-groups. This plant very closely
resembles N. graciliflora Elmer, but is recorded from limestone in northern
Mindanao, so may yet be distinct, if so it may have evolved only recently.
The second is a record claimed to be Nepenthes campanulata (but still to
be confirmed with a specimen) from that part of Palawan closest to Borneo
(Clarke et al. 2014). Considering the vast extent of the Philippine archipelago
and the multiple outcrops of limestone, the records of Nepenthes from that
country are puzzlingly minute compared with Borneo.
However, it may be that as with N. treubiana, the limestone substrate of one or
more species has not been recorded. It is likely that more limestone species
of Nepenthes will be found as exploration progresses. Yet limestone is a
dangerous substrate on which to depend, especially in the neighbourhood
of transport links and cities: it is the principle component of cement, crucial
to concrete for constructing large buildings and transport and industrial
infrastructure. Extensive areas of the substrate remain to be surveyed for
plants in New Guinea, and, surely, limestone there, in the Philippines, and
perhaps Sulawesi, will one day yield yet more calcicole Nepenthes.
Catalano, M. 2014. Nepenthes rosea, una nuova specie dalla Thailandia peninsulare. AIPC
Magazine 36: 24–31.
Cheek M, Jebb M. 2001. Nepenthaceae. Flora Malesiana 15. Nationaal Herbarium Nederland,
Leiden. 157 pp.
Cheek M, Jebb M. 2009. Nepenthes group Montanae (Nepenthaceae) in Indo-China,
with N. thai and N. bokor described as new. Kew Bulletin 64(2): 319–325. https://doi.
Cheek M, Jebb M, Murphy B, Mambor F. 2018. Nepenthes section Insignes in Indonesia, with
two new species. Blumea 62(3): 174–178.
Clarke C, Lee C, Enar V. 2014. Observations of the natural history and ecology of Nepenthes
campanulata. Carnivorous Plant Newsletter 43(1): 7–13.
Clarke C, Moran J. 2016. Climate, soils and vicariance - their roles in shaping the diversity
and distribution of Nepenthes in Southeast Asia. Plant and Soil 403(1–2): 37–51. https://doi.
Lee C. 2004. Nepenthes. In: Yong H, Ng F, Yen E (eds.). Sarawak Bau limestone biodiversity.
The Sarawak Museum Journal 59 (Special Issue No. 6): 171–177.
Micheler M, Gronemeyer T, Wistuba A, Marwinski D, Suarez W, Amoroso V. 2013. Nepenthes
viridis, eine neue Nepenthes-Art von der Insel Dinagat, Philippinen. Das Taublatt 76: 4–21.
Nuanlaong S, Onsanit S, Chusangrach V, Suraninpong P. 2016. A new species
of Nepenthes (Nepenthaceae) from Thailand. Thai Forest Bulletin (Botany) 44(2): 128–
Robinson A, Nerz J, Wistuba A. 2011. Nepenthes epiphytica, a new pitcher plant from
East Kalimantan. In: McPherson S. New Nepenthes: Volume One. Redfern Natural History
Productions, Poole. pp. 36–51.
Full-text available
Nepenthes, as the largest family of carnivorous plants, is found with an extensive geographical distribution throughout the Malay Archipelago, specifically in Borneo, Philippines, and Sumatra. Highland species are able to tolerate cold stress and lowland species heat stress. Our current understanding on the adaptation or survival mechanisms acquired by the different Nepenthes species to their climatic conditions at the phytochemical level is, however, limited. In this study, we applied an eco-metabolomics approach to identify temperature stressed individual metabolic fingerprints of four Nepenthes species: the lowlanders N. ampullaria, N. rafflesiana and N. northiana, and the highlander N. minima. We hypothesized that distinct metabolite regulation patterns exist between the Nepenthes species due to their adaptation towards different geographical and altitudinal distribution. Our results revealed not only distinct temperature stress induced metabolite fingerprints for each Nepenthes species, but also shared metabolic response and adaptation strategies. The interspecific responses and adaptation of N. rafflesiana and N. northiana likely reflected their natural habitat niches. Moreover, our study also indicates the potential of lowlanders, especially N. ampullaria and N. rafflesiana, to produce metabolites needed to deal with increased temperatures, offering hope for the plant genus and future adaption in times of changing climate.
Full-text available
A report from a trip to Southern Thailand, with Nepenthes rosea described as a new species of the N. thorelii aggregate. Discovery, habitat and morphology of a unique taxon belonging to one of the most confusing groups within the genus.
Full-text available
Eight taxa of Nepenthes have been recorded from the Bau Limestone Area, which includes one limestone obligate and two natural hybrids. The hybrid N. northiana x gracilis is herein recorded and formally described. The limestone obligate N. northiana is endemic to the Bau Limestone Area.
Full-text available
A review of new data relating to Nepenthes insignis in Indonesia indicates that three taxa in section Insignes, not one, are present in New Guinea. One of these, endemic to the limestone of the island of Biak, is formally named as Nepenthes biak and assessed as Critically Endangered; the other, from limestone of the Raja Ampat islands is provisionally distinguished as Nepenthes sp. Raja Ampat, since only images are available.
Full-text available
This paper describes and illustrates a new species of Nepenthaceae, Nepenthes krabiensis . The new species is closely related to N. rosea which has been found in the same habitat of the wildlife sanctuary of Krabi Province in Sothern Thailand.
Full-text available
Background The Palaeotropical pitcher plant genus Nepenthes (Nepenthaceae) is characterized by specialized nutrient sequestration strategies, narrow endemism, and a patchy distribution in which vicariance is believed to have played a fundamental role. Scope Using recent studies of the effects of climate, soil type and vicariance, we review patterns of diversity and endemism in Nepenthes. First we consider how climate influences the geographical range of the genus and diversity of prey trapping mechanisms. Second, we examine edaphic influences, specifically the relationship between limestone and ultramafic soils and the obligate edaphic endemic Nepenthes that inhabit them. Third, we examine the role of vicariance, with regards to the patchy distribution of suitable habitats throughout Southeast Asia, and the passive dispersal mechanism of Nepenthes seeds. Conclusions Climate is the principal determinant of variation in pitcher functional traits and in perhumid environments, may drive the evolution of alternative nutrient sequestration strategies. Although little is known about the ecophysiological relationships between soil type and obligate edaphic Nepenthes, ultramafic and limestone substrates may strongly influence vegetation physiognomy, creating a diversity of environmental niches that are exploited by specialized Nepenthes species. Finally, the complex geology and geography of the Malay Archipelago drives diversification through vicariance.
Full-text available
Summary A key is presented to the Nepenthes group Montanae in Peninsular Malaysia, Thailand and Cambodia. Nepenthes bokor Cheek is described from Cambodia and Nepenthes thai Cheek from peninsular Thailand. The affinities of both taxa are discussed and their conservation status assessed.
Nepenthes campanulata is a little known species from limestone cliff habitats in Borneo. In this study, we conducted the first field-based survey of pitcher dimensions and the prey and invertebrate fauna in N. campanulata pitchers, sampled from plants growing on the cliff face above Deer Cave in Gunung Mulu National Park. We found that the dominant prey taxon is Diptera, followed by Formicidae. The metazoan community that inhabits the pitchers consists of just three species, making it one of the simplest in the genus. The pitchers of N. campanulata have a unique structure among Nepenthes, which may be related to the highly specialized habitat that the plant occurs in. Prior to this study, N. campanulata had been recorded at just two localities: Mt. Ilas Bungaan in East Kalimantan, and Gunung Mulu National Park in Sarawak. However, on a recent expedition to Palawan, we observed plants that we identified as N. campanulata, which represents a remarkable extension to the geographical range of this species.
Nepenthaceae. Flora Malesiana 15
  • M Cheek
  • M Jebb
Cheek M, Jebb M. 2001. Nepenthaceae. Flora Malesiana 15. Nationaal Herbarium Nederland, Leiden. 157 pp.
Nepenthes viridis, eine neue Nepenthes-Art von der Insel Dinagat
  • M Micheler
  • T Gronemeyer
  • A Wistuba
  • D Marwinski
  • W Suarez
  • V Amoroso
Micheler M, Gronemeyer T, Wistuba A, Marwinski D, Suarez W, Amoroso V. 2013. Nepenthes viridis, eine neue Nepenthes-Art von der Insel Dinagat, Philippinen. Das Taublatt 76: 4-21.