Carnivorous Plants / Insectivorous Plants
The Botanical Society of America is pleased to provide the "Carnivorous Plant" pages. We are in the early stages of developing
this section of our site; check back regularly. In the meantime, enjoy the images
(mainly donated by members) and the stories they tell. We hope these strange
and interesting plants open up your possibilities for asking new questions about
the fascinating lives of plants!
Carnivorous plants have the most bizarre adaptations to low-nutrient
environments. These plants obtain some nutrients by trapping and digesting various
invertebrates, and occasionally even small frogs and mammals. Because insects
are one of the most common prey items for most carnivorous plants, they are
sometimes called insectivorous plants. It is not surprising that the most common
habitat for these plants is in bogs and fens, where nutrient concentrations
are low but water and sunshine seasonally abundant. As many as thirteen species
of carnivorous plants have been found in a single bog (Folkerts, 1982). Most
plants absorb nitrogen from the soil through their roots. But carnivorous plants
absorb nitrogen from their animal prey through their leaves specially modified
as traps.
Traps work in a variety of ways.
Pitfall traps
of pitcher plants are leaves folded into deep, slippery pools filled with digestive enzymes.
Flypaper (or sticky or adhesive traps) of sundews
and butterworts are leaves covered in stalked glands that exude sticky mucilage.
Snap traps (or steel traps) of the Venus flytrap and waterwheel
plant are hinged leaves that snap shut when trigger hairs are touched.
Suction
traps, unique to bladderworts, are highly modified leaves in the shape
of a bladder with a hinged door lined with trigger hairs.
Lobster-pot
traps of corkscrew plants are twisted tubular channels lined with hairs and
glands.
Carnivorous plants are fascinating because, even when they
are not trapping insects, their unusual forms are intriguing. However, you should
not collect plants in the wild because most of them are relatively rare. Habitat
destruction and over collection are two of the greatest conservation threats
to carnivorous plants. If you are interested in growing carnivorous plants in
your home or classroom, purchase the plants from a reputable grower who uses
tissue culture or vegetative means to grow the plant, or starts them from seeds.
Unraveling the story of carnivorous plant evolution and ecology
has occupied biologists for centuries. Charles Darwin's extensive experiments
confirmed the carnivorous habit for several genera. Carnivory has been documented
in at least 9 plant families and 600 species.
We now know that the carnivorous
habit evolved independently in many plant lineages (Albert et al., 1992; Ellison
and Gotelli, 2001; Cameron et al., 2002; Muller et al., 2004). Pitfall traps
evolved independently in four plant groups (the eudicot orders Caryophyllales,
Oxalidales, Ericales, and the monocot family Bromeliaceae), and sticky traps,
in at least three (the Caryophyllales, Ericales, and Lamiales). These are examples
of convergent evolution. In contrast, the snap trap and lobster-pot
traps evolved only once among carnivorous plants. In the descriptions below,
the plant groups and names follow the Angiosperm Phylogeny Group II (1993) and
Peter Stevens' Angiosperm Phylogeny Website, which do not use formal classification
ranks above the level of the order.
Kingdom: Plantae
— Eudicots, Basal Eudicots
Order: Caryophyllales
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Family: Nepenthaceae
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Family: Drosophyllaceae
One
species occupying coastal habitats in northern Morocco, Portugal, and southwest
Spain.
For more Drosophyllum
information - CLICK HERE
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Family: Dioncophyllaceae
Genus: Triphyophyllum
One species occupying
rainforest habitats in West Africa (Liberia, Sierra Leone, and Ivory Coast).
More
Triphyophyllum peltatum information COMING SOON!
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Family: Droseraceae
Genus: Drosera
Sundew
Currently 152 listed species occupying temperate
and tropical habitats throughout the world.
For more
Drosera information and images - CLICK
HERE |
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Family: Droseraceae
Genus: Dionaea
Venus Flytrap
One
species occupying habitats in the southeastern United States of America
(North Carolina, South Carolina).
For more Dionea
muscipula information and images - CLICK
HERE
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Family: Droseraceae
Genus: Aldrovanda
Waterwheel Plant
One species occupying
aquatic habitats in Europe, Asia, and Australia. Once widely distributed
in Africa, India, and Japan.
More
Aldrovanda vesiculosa information COMING SOON!
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Kingdom: Plantae — Eudicots,
Rosids, Eurosids I
Order: Oxalidales
Kingdom: Plantae — Eudicots,
Asterids, Basal Asterids
Order: Ericales
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Family: Sarraceniaceae
Genus: Darlingtonia
Cobra Lily
One species occupying boggy habitats in the northwest
United States of America (southern Oregon, northern California).
For more
Darlingtonia californica information CLICK HERE
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Family: Sarraceniaceae
Genus: Sarracenia
Pitcher Plant
Currently 10 listed species occupying habitats
in eastern North America (central Canada to southeastern United States
of America).
For more
Sarracenia information - CLICK
HERE
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Family: Sarraceniaceae
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Family: Roridulaceae
Genus: Roridula
Bug Plant or South African Fly Bush
Two species occuring
in fynbos of Southern Africa. Roridula
has sticky leaves to trap insects but lacks enzymes to digest them. It
has sometimes been considered as carnivorous, sometimes not. Evaluate
the evidence and decide for yourself.
More
Roridula information and images COMING SOON!
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Kingdom: Plantae — Eudicots,
Asterids, Euasterids I
Order: Lamiales
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Family: Lentibulariaceae
Genus: Utricularia
Bladderwort
Currently 220 listed species occupying temperate and tropical
habitats throughout the world--the most diverse and widespread genus of
carnivorous plants.
For more
Utricularia information and images - CLICK
HERE
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Family: Lentibulariaceae
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Family: Lentibulariaceae
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Family: Byblidaceae
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Kingdom: Plantae — Monocotyledons,
Commelinids
Order: Poales, Family:
Bromeliaceae
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Subfamily Pitcairnioideae
Genus: Brocchinia
Of the 5 species in the genus occupying lowland savanna
and mountain habitats in South America, at least 2 species are carnivorous.
More
Brocchinia reducta and B. hectioides information COMING
SOON!
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Subfamily Tillandsioideae
Genus: Catopsis
Of the 21 species
in the genus, 1 species is carnivorous. It occupies humid habitats in
South America, Central America, Mexico, the West Indies, and Florida,
U.S.A.
More
Catposis berteroniana information COMING SOON!
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Protocarnivorous Plants and Predatory Fungi
Carnivorous plants have features to attract, trap, kill, and digest prey, and
absorb nutrients. A number of plants have only some of these characteristics.
Glands that secrete sticky substances are found in many plants. Pitcher-like
tanks are common in bromeliads and in few other plants. While perhaps
not fully fledged sticky traps or pitfall traps, these features hint of the
potential for carnivory. The list of plants described as near carnivorous, protocarnivorous,
or borderline carnivorous is quite diverse, including Ibicella lutea
(Mameli, 1916), Dipsacus (Christy, 1923), Passiflora foetida
(Radhamani et al., 1995), Paepalanthus bromeloides (Jolivet, 1998),
and Geranium viscosissimum and Potentilla arguta (Spomer,
1999). No single definitive list exists. Ibicella lutea, which has
not been studied since 1916 (Juniper et al., 1989), is sometimes listed
as carnivorous, and Catopsis berteroniana is sometimes described as
borderline. The ability to digest prey and absorb the amino acids is considered
the real clincher.
Carnivory is more widespread than just the plant and animal kingdoms. The fungi
kingdom has flesh eaters also (Pramer, 1964). Living in the soil are over 200
species of fungi (identified as zygomycetes, basidiomycetes, and hyphomycetes)
that use special structures to trap nematodes. Like carnivorous plants, these
fungi have the ability to trap prey and to absorb nutrients from the body of
their prey. The traps of fungi come in two general types: constricting rings
(active traps) and adhesive structures (passive traps). These trap types occur
in separate fungi lineages (Ahren et al., 1998).
Special thanks to Dr. Sherwin Carlquist, Dr. Janice Glime,
Dr. David Webb, Dr. Barry Rice (www.sarracenia.com), Dr. J. Howard
Frank and the International Carnivorous Plant Society for their
contributions to these pages!
References
Ahrén, D., Bjõrn,
M. U., and Tunlind, A. 1998. Phylogeny of nematode-trapping fungi based
on 18S rDNA sequences. FEMS Microbiology Letters 158: 179--184.
Albert, V.A., S.E. Williams, and M.W. Chase. 1992. Carnivorous
plants: phylogeny and structural evolution. Science 257: 1491--14955.
Angiosperm Phylogeny Group. 2003. An update of the Angiosperm
Phylogeny Group classification for the orders and families of flowering plants:
APG II. Botanical Journal of the Linnean Society 141: 399--436.
Cameron, K.M., Wurdack, K.J., and Jobson, R.W. 2002. Molecular evidence
for the common origin of snap-traps among carnivorous plants. American Journal
of Botany 89:1503--1509.
Christy, M. 1923. The common teasel as a carnivorous plant. Journal
of Botany 61: 33--45.
Ellison, A.M. and Gotelli, N.J. 2001. Evolutionary ecology of
carnivorous plants. Trends in Ecology and Evolution 16:623--629.
Folkerts, G. W. 1982. The gulf coast pitcher plant bogs. American
Scientist 70: 260--267.
Jolivet, P. 1998. Interrelationships between insects and plants.
CRC Press, Boca Raton.
Juniper, B.E., Robins, R.J., and Joel, D.M. 1989. The Carnivorous
Plants. Academic Press, London.
Mameli, E. 1916. Ricerche anatomiche, fisiologiche e biologiche
sulla Martynia lutea Lindl. Atti dell'Universita di Pavia, Serie 2, 16, 137--188.
Müller, K., Borsch, T., Legendre, L., Porembski, S., Theisen, I., and Barthlott,
W. 2004. Evolution of carnivory in Lentibulariaceae and the Lamiales.
Plant Biology 6: 477-490.
Pramer, D. 1964. Nematode-trapping fungi. Science 144: 902--908.
Radhamani, T.R., Sudarshana, L., and Krishnan, R. 1995. Defence
and carnivory: dual roles of bracts in Passiflora foetida. Journal of
Biosciences 20: 657--664.
Spomer, G.G. 1999. Evidence of protocarnivorous capabilities
in Geranium viscosissimum and Potentilla arguata and other sticky
plants. International Journal of Plant Science 160:98--101.
Stevens, P. (2001 onwards) Angiosperm Phylogeny Website. Version
6, May 2005 [and more or less continuously updated since].
Intrigued? Want to see more? Take a look at the following pages!
Investigate the American Journal of Botany
images & cover stories online: BSA
Online Image Collection
Want to surf the web for more carnivorous plant information? —Try these
sites:
International
Carnivorous Plant Society, www.sarracenia.com, Mysterious
Venus Flytrap!,
Flora of North America Carnivorous Plant Fact Sheet,
Classroom Carnivoury
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