Carnivorous plant
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Carnivorous plants are
plant Plants are predominantly photosynthetic eukaryotes of the kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all current definitions of Plantae exclu ...
s that derive some or most of their nutrients from trapping and consuming
animal Animals are multicellular, eukaryotic organisms in the Kingdom (biology), biological kingdom Animalia. With few exceptions, animals Heterotroph, consume organic material, Cellular respiration#Aerobic respiration, breathe oxygen, are Motilit ...
s or
protozoans Protozoa (singular: protozoan or protozoon; alternative plural: protozoans) are a group of single-celled eukaryotes, either free-living or parasitic, that feed on organic matter such as other microorganisms or organic tissues and debris. Histo ...
, typically
insect Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three pairs ...
s and other
arthropod Arthropods (, (gen. ποδός)) are invertebrate animals with an exoskeleton, a Segmentation (biology), segmented body, and paired jointed appendages. Arthropods form the phylum Arthropoda. They are distinguished by their jointed limbs and Arth ...
s. Carnivorous plants still generate some of their
energy In physics, energy (from Ancient Greek: ἐνέργεια, ''enérgeia'', “activity”) is the quantitative property that is transferred to a body or to a physical system, recognizable in the performance of work and in the form of heat a ...
from
photosynthesis Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that, through cellular respiration, can later be released to fuel the organism's activities. Some of this chemical energy is stored i ...
. Carnivorous plants have adapted to grow in places where the
soil Soil, also commonly referred to as earth or dirt, is a mixture of organic matter, minerals, gases, liquids, and organisms that together support life. Some scientific definitions distinguish ''dirt'' from ''soil'' by restricting the former te ...
is thin or poor in
nutrient A nutrient is a substance used by an organism to survive, grow, and reproduce. The requirement for dietary nutrient intake applies to animals, plants, fungi, and protists. Nutrients can be incorporated into cells for metabolic purposes or excret ...
s, especially
nitrogen Nitrogen is the chemical element with the symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at se ...
, such as acidic bogs. They can be found on all continents except Antarctica, as well as many Pacific islands. In 1875
Charles Darwin Charles Robert Darwin ( ; 12 February 1809 – 19 April 1882) was an English naturalist, geologist, and biologist, widely known for his contributions to evolutionary biology. His proposition that all species of life have descended fr ...
published '' Insectivorous Plants'', the first
treatise A treatise is a formal and systematic written discourse on some subject, generally longer and treating it in greater depth than an essay, and more concerned with investigating or exposing the principles of the subject and its conclusions."Treat ...
to recognize the significance of carnivory in plants, describing years of painstaking research. True carnivory is believed to have evolved independently at least 12 times in five different
orders Order, ORDER or Orders may refer to: * Categorization, the process in which ideas and objects are recognized, differentiated, and understood * Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of d ...
of flowering plants, and is represented by more than a dozen
genera Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclat ...
. This classification includes at least 583 species that attract, trap, and kill
prey Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill the ...
, absorbing the resulting available nutrients.
Venus flytrap The Venus flytrap (''Dionaea muscipula'') is a carnivorous plant native to subtropical wetlands on the East Coast of the United States in North Carolina and South Carolina. It catches its prey—chiefly insects and arachnids—with a trapping ...
(''Dionaea muscipula''),
pitcher plant Pitcher plants are several different carnivorous plants which have modified leaves known as pitfall traps—a prey-trapping mechanism featuring a deep cavity filled with digestive liquid. The traps of what are considered to be "true" pitcher p ...
(''Cephalotus follicularis''), and
bladderwort ''Utricularia'', commonly and collectively called the bladderworts, is a genus of carnivorous plants consisting of approximately 233 species (precise counts differ based on classification opinions; a 2001 publication lists 215 species).Salmon, Br ...
(''Utricularia gibba'') can be seen as exemplars of key traits genetically associated with carnivory: trap leaf development, prey digestion, and nutrient absorption. The number of known species has increased by approximately 3 species per year since the year 2000. Additionally, over 300
protocarnivorous plant A protocarnivorous plant (sometimes also paracarnivorous, subcarnivorous, or borderline carnivore), according to some definitions, traps and kills insects or other animals but lacks the ability to either directly digest or absorb nutrients from it ...
species in several genera show some but not all of these characteristics. A 2020 assessment has found that roughly one quarter are threatened with
extinction Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...
from human actions.


Definition

Plants are considered carnivorous if they have these five traits: # capture prey in traps # kill the captured prey # digest the captured prey # absorb nutrients from the killed and digested prey # use those nutrients to grow and develop. Other traits may include the attraction and retention of prey.


Trapping mechanisms

Five basic trapping mechanisms are found in carnivorous plants. # Pitfall traps (
pitcher plant Pitcher plants are several different carnivorous plants which have modified leaves known as pitfall traps—a prey-trapping mechanism featuring a deep cavity filled with digestive liquid. The traps of what are considered to be "true" pitcher p ...
s) trap prey in a rolled leaf that contains a pool of
digestive enzyme Digestive enzymes are a group of enzymes that break down polymeric macromolecules into their smaller building blocks, in order to facilitate their absorption into the cells of the body. Digestive enzymes are found in the digestive tracts of anim ...
s or
bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among ...
. # Flypaper traps use a sticky
mucilage Mucilage is a thick, gluey substance produced by nearly all plants and some microorganisms. These microorganisms include protists which use it for their locomotion. The direction of their movement is always opposite to that of the secretion of m ...
. # Snap traps utilise rapid leaf movements. # Bladder traps suck in prey with a bladder that generates an internal
vacuum A vacuum is a space devoid of matter. The word is derived from the Latin adjective ''vacuus'' for "vacant" or "void". An approximation to such vacuum is a region with a gaseous pressure much less than atmospheric pressure. Physicists often dis ...
. # Lobster-pot traps, also known as eel traps, use inward-pointing
hairs Hair is a protein filament that grows from follicles found in the dermis. Hair is one of the defining characteristics of mammals. The human body, apart from areas of glabrous skin, is covered in follicles which produce thick terminal and f ...
to force prey to move towards a digestive organ. These traps may be active or passive, depending on whether movement aids the capture of prey. For example, '' Triphyophyllum'' is a passive flypaper that secretes mucilage, but whose leaves do not grow or move in response to prey capture. Meanwhile,
sundew ''Drosera'', which is commonly known as the sundews, is one of the largest genera of carnivorous plants, with at least 194 species. 2 volumes. These members of the family Droseraceae lure, capture, and digest insects using stalked mucilaginou ...
s are active flypaper traps whose leaves undergo rapid
acid growth Acid growth refers to the ability of plant cells and plant cell walls to elongate or expand quickly at low (acidic) pH. The cell wall needs to be modified in order to maintain the turgor pressure. This modification is controlled by plant hormones l ...
, which is an expansion of individual cells as opposed to
cell division Cell division is the process by which a parent cell (biology), cell divides into two daughter cells. Cell division usually occurs as part of a larger cell cycle in which the cell grows and replicates its chromosome(s) before dividing. In eukar ...
. The rapid acid growth allows the sundews'
tentacle In zoology, a tentacle is a flexible, mobile, and elongated organ present in some species of animals, most of them invertebrates. In animal anatomy, tentacles usually occur in one or more pairs. Anatomically, the tentacles of animals work main ...
s to bend, aiding in the retention and
digestion Digestion is the breakdown of large insoluble food molecules into small water-soluble food molecules so that they can be absorbed into the watery blood plasma. In certain organisms, these smaller substances are absorbed through the small intest ...
of prey.


Pitfall traps

Characterised by an internal chamber, pitfall traps are thought to have evolved independently at least six times. This particular adaptation is found within the families
Sarraceniaceae Sarraceniaceae are a family of pitcher plants, belonging to order Ericales (previously Nepenthales). The family comprises three extant genera: ''Sarracenia'' (North American pitcher plants), '' Darlingtonia'' (the cobra lily or California pitc ...
'' (Darlingtonia,
Heliamphora The genus ''Heliamphora'' ( or ; Greek: ''helos'' "marsh" and ''amphoreus'' " amphora") contains 23 species of pitcher plants endemic to South America.McPherson, S., A. Wistuba, A. Fleischmann & J. Nerz 2011. '' Sarraceniaceae of South America''. ...
,
Sarracenia ''Sarracenia'' ( or ) is a genus comprising 8 to 11 species of North American pitcher plants, commonly called trumpet pitchers. The genus belongs to the family Sarraceniaceae, which also contain the closely allied genera '' Darlingtonia'' an ...
''), Nepenthaceae (''
Nepenthes ''Nepenthes'' () is a genus of carnivorous plants, also known as tropical pitcher plants, or monkey cups, in the monotypic family Nepenthaceae. The genus includes about 170 species, and numerous natural and many cultivated hybrids. They are mos ...
''), and Cephalotaceae (''Cephalotus''). Within the family
Bromeliaceae The Bromeliaceae (the bromeliads) are a family of monocot Monocotyledons (), commonly referred to as monocots, (Lilianae ''sensu'' Chase & Reveal) are grass and grass-like flowering plants (angiosperms), the seeds of which typically contain o ...
'','' pitcher morphology and carnivory evolved twice ''(
Brocchinia ''Brocchinia'' is a genus of the botanical family Bromeliaceae, and is the sole genus of the subfamily Brocchinioideae, containing 20 species. The genus is named for Giovanni Battista Brocchi, Italian naturalist (1772–1826). ''Brocchinia'' sp ...
'' and ''
Catopsis ''Catopsis'' is a genus in the botanical family Bromeliaceae, subfamily Tillandsioideae. The genus name is from the Greek “kata” (hanging down) and “opsis” (appearance). ''Catopsis'' is a genus of plants widespread across much of Latin A ...
).'' Because these families do not share a common ancestor who also had pitfall trap morphology, carnivorous pitchers are an example of
convergent evolution Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last com ...
. A passive trap, pitfall traps attract prey with nectar bribes secreted by the
peristome Peristome (from the Greek ''peri'', meaning 'around' or 'about', and ''stoma'', 'mouth') is an anatomical feature that surrounds an opening to an organ or structure. Some plants, fungi, and shelled gastropods have peristomes. In mosses In mosses, ...
and bright flower-like
anthocyanin Anthocyanins (), also called anthocyans, are water-soluble vacuolar pigments that, depending on their pH, may appear red, purple, blue, or black. In 1835, the German pharmacist Ludwig Clamor Marquart gave the name Anthokyan to a chemical compo ...
patterning within the pitcher. The linings of most pitcher plants are covered in a loose coating of
wax Waxes are a diverse class of organic compounds that are lipophilic, malleable solids near ambient temperatures. They include higher alkanes and lipids, typically with melting points above about 40 °C (104 °F), melting to giv ...
y flakes which are slippery for insects, causing them to fall into the pitcher. Once within the pitcher structure, digestive enzymes or mutualistic species break down the prey into an absorbable form for the plant. Water can become trapped within the pitcher, making a habitat for other flora and fauna. This type of 'water body' is called a
Phytotelma Phytotelma (plural phytotelmata) is a small water-filled cavity in a terrestrial plant. The water accumulated within these plants may serve as the habitat for associated fauna and flora. A rich literature in German summarised by Thienemann (19 ...
. The simplest pitcher plants are probably those of ''
Heliamphora The genus ''Heliamphora'' ( or ; Greek: ''helos'' "marsh" and ''amphoreus'' " amphora") contains 23 species of pitcher plants endemic to South America.McPherson, S., A. Wistuba, A. Fleischmann & J. Nerz 2011. '' Sarraceniaceae of South America''. ...
'', the marsh
pitcher plant Pitcher plants are several different carnivorous plants which have modified leaves known as pitfall traps—a prey-trapping mechanism featuring a deep cavity filled with digestive liquid. The traps of what are considered to be "true" pitcher p ...
. In this
genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...
, the traps are clearly derived from a simple rolled leaf whose margins have sealed together. These plants live in areas of high rainfall in South America such as Mount Roraima and consequently have a problem ensuring their pitchers do not overflow. To counteract this problem,
natural selection Natural selection is the differential survival and reproduction of individuals due to differences in phenotype. It is a key mechanism of evolution, the change in the heritable traits characteristic of a population over generations. Charle ...
has favoured the evolution of an overflow similar to that of a bathroom
sink A sink is a bowl-shaped plumbing fixture for washing hands, dishwashing, and other purposes. Sinks have a tap (faucet) that supply hot and cold water and may include a spray feature to be used for faster rinsing. They also include a drain t ...
—a small gap in the zipped-up leaf margins allows excess water to flow out of the pitcher. In the genus ''Sarracenia'', the problem of pitcher overflow is solved by an operculum, which is essentially a flared leaflet that covers the opening of the rolled-leaf tube and protects it from rain. Possibly because of this improved waterproofing, ''Sarracenia'' species secrete enzymes such as
protease A protease (also called a peptidase, proteinase, or proteolytic enzyme) is an enzyme that catalyzes (increases reaction rate or "speeds up") proteolysis, breaking down proteins into smaller polypeptides or single amino acids, and spurring the ...
s and
phosphatase In biochemistry, a phosphatase is an enzyme that uses water to cleave a phosphoric acid Ester, monoester into a phosphate ion and an Alcohol (chemistry), alcohol. Because a phosphatase enzyme catalysis, catalyzes the hydrolysis of its Substrate ...
s into the digestive fluid at the bottom of the pitcher; Most ''Heliamphora'' rely on bacterial digestion alone with the exception of a single species,
Heliamphora tatei ''Heliamphora tatei'' (after George Henry Hamilton Tate) is a species of marsh pitcher plant endemic to Cerro Duida, Cerro Huachamacari and Cerro Marahuaca in Venezuela. It is closely related to '' H. macdonaldae'', '' H. neblinae'', ...
, which does produce digestive enzymes. The enzymes digest the
protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...
s and
nucleic acid Nucleic acids are biopolymers, macromolecules, essential to all known forms of life. They are composed of nucleotides, which are the monomers made of three components: a 5-carbon sugar, a phosphate group and a nitrogenous base. The two main cl ...
s in the prey, releasing
amino acid Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha am ...
s and
phosphate In chemistry, a phosphate is an anion, salt, functional group or ester derived from a phosphoric acid. It most commonly means orthophosphate, a derivative of orthophosphoric acid . The phosphate or orthophosphate ion is derived from phospho ...
ions, which the plant absorbs. In at least one species, ''
Sarracenia flava ''Sarracenia flava'', the yellow pitcherplant, is a carnivorous plant in the family Sarraceniaceae. Like all the Sarraceniaceae, it is native to the New World. Its range extends from southern Alabama, through Florida and Georgia, to the coastal ...
'', the nectar bribe is laced with
coniine Coniine is a poisonous chemical compound, an alkaloid present in and isolable from poison hemlock ('' Conium maculatum''), where its presence has been a source of significant economic, medical, and historico-cultural interest; coniine is also prod ...
, a toxic
alkaloid Alkaloids are a class of basic, naturally occurring organic compounds that contain at least one nitrogen atom. This group also includes some related compounds with neutral and even weakly acidic properties. Some synthetic compounds of similar ...
also found in hemlock, which probably increases the efficiency of the traps by intoxicating prey. '' Darlingtonia californica'', the cobra plant, possesses an adaptation also found in ''
Sarracenia psittacina ''Sarracenia psittacina'', also known as the parrot pitcherplant, is a carnivorous plant in the genus ''Sarracenia''. Like all the ''Sarracenia'', it is native to North America, in the Southeastern United States. ''Sarracenia psittacina'' emp ...
'' and, to a lesser extent, in ''
Sarracenia minor ''Sarracenia minor'', also known as the hooded pitcherplant, is a perennial, terrestrial, rhizomatous, herbaceous, carnivorous plant in the genus ''Sarracenia''. Like all the ''Sarracenia'', it is native to North America. Etymology In 1788, t ...
'': the operculum is balloon-like and almost seals the opening to the tube. This balloon-like chamber is pitted with
areola The human areola (''areola mammae'', or ) is the pigmented area on the breast around the nipple. Areola, more generally, is a small circular area on the body with a different histology from the surrounding tissue, or other small circular ar ...
e,
chlorophyll Chlorophyll (also chlorophyl) is any of several related green pigments found in cyanobacteria and in the chloroplasts of algae and plants. Its name is derived from the Greek words , ("pale green") and , ("leaf"). Chlorophyll allow plants to a ...
-free patches through which light can penetrate. Insects, mostly ants, enter the chamber via the opening underneath the balloon. Once inside, they tire themselves trying to escape from these false exits, until they eventually fall into the tube. Prey access is increased by the "fish tails", outgrowths of the operculum that give the plant its name. Some seedling ''Sarracenia'' species also have long, overhanging opercular outgrowths; ''Darlingtonia'' may therefore represent an example of
neoteny Neoteny (), also called juvenilization,Montagu, A. (1989). Growing Young. Bergin & Garvey: CT. is the delaying or slowing of the physiological, or somatic, development of an organism, typically an animal. Neoteny is found in modern humans compa ...
. The second major group of pitcher plants are the monkey cups or tropical pitcher plants of the genus ''
Nepenthes ''Nepenthes'' () is a genus of carnivorous plants, also known as tropical pitcher plants, or monkey cups, in the monotypic family Nepenthaceae. The genus includes about 170 species, and numerous natural and many cultivated hybrids. They are mos ...
''. In the hundred or so species of this genus, the pitcher is borne at the end of a
tendril In botany, a tendril is a specialized stem, leaf or petiole with a threadlike shape used by climbing plants for support and attachment, as well as cellular invasion by parasitic plants such as ''Cuscuta''. There are many plants that have tendr ...
, which grows as an extension to the
midrib This glossary of botanical terms is a list of definitions of terms and concepts relevant to botany and plants in general. Terms of plant morphology are included here as well as at the more specific Glossary of plant morphology and Glossary o ...
of the leaf. Most species catch insects, although the larger ones, such as ''
Nepenthes rajah ''Nepenthes rajah'' is a carnivorous pitcher plant species of the family Nepenthaceae. It is endemic to Mount Kinabalu and neighbouring Mount Tambuyukon in Sabah, Malaysian Borneo.Clarke 1997, p. 123. ''Nepenthes rajah'' grows exclusively on ...
'', also occasionally take small
mammal Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or ...
s and
reptile Reptiles, as most commonly defined are the animals in the class Reptilia ( ), a paraphyletic grouping comprising all sauropsids except birds. Living reptiles comprise turtles, crocodilians, squamates (lizards and snakes) and rhynchocephalians ( ...
s. ''
Nepenthes bicalcarata ''Nepenthes bicalcarata'' (; from Latin for "two-spurred"), also known as the fanged pitcher-plant,Phillipps, A. & A. Lamb 1996. ''Pitcher-Plants of Borneo''. Natural History Publications (Borneo), Kota Kinabalu. is a tropical pitcher plant ende ...
'' possesses two sharp thorns that project from the base of the operculum over the entrance to the pitcher. These likely serve to lure insects into a precarious position over the pitcher mouth, where they may lose their footing and fall into the fluid within. The pitfall trap has evolved independently in at least two other groups. The Albany pitcher plant ''
Cephalotus ''Cephalotus'' ( or ; Greek: ''κεφαλή'' "head", and ''οὔς''/''ὠτός'' "ear", to describe the head of the anthers) is a genus which contains one species, ''Cephalotus follicularis'' the Albany pitcher plant, a small carnivorous pi ...
follicularis'' is a small pitcher plant from
Western Australia Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to th ...
, with
moccasin A moccasin is a shoe, made of deerskin or other soft leather, consisting of a sole (made with leather that has not been "worked") and sides made of one piece of leather, stitched together at the top, and sometimes with a vamp (additional panel o ...
-like pitchers. The rim of its pitcher's opening (the
peristome Peristome (from the Greek ''peri'', meaning 'around' or 'about', and ''stoma'', 'mouth') is an anatomical feature that surrounds an opening to an organ or structure. Some plants, fungi, and shelled gastropods have peristomes. In mosses In mosses, ...
) is particularly pronounced (both secrete
nectar Nectar is a sugar-rich liquid produced by plants in glands called nectaries or nectarines, either within the flowers with which it attracts pollinating animals, or by extrafloral nectaries, which provide a nutrient source to animal mutualists ...
) and provides a thorny overhang to the opening, preventing trapped insects from climbing out. The final carnivore with a pitfall-like trap is the bromeliad ''
Brocchinia reducta ''Brocchinia reducta'' is one of a few carnivorous plant, carnivorous Bromeliaceae, bromeliads. It is native to southern Venezuela, Brazil, Colombia, and Guyana, and is found in nutrient-poor soil. ''B. reducta'' adapts to different environments ...
''. Like most relatives of the
pineapple The pineapple (''Ananas comosus'') is a tropical plant with an edible fruit; it is the most economically significant plant in the family Bromeliaceae. The pineapple is indigenous to South America, where it has been cultivated for many centuri ...
, the tightly packed, waxy leaf bases of the strap-like leaves of this species form an
urn An urn is a vase, often with a cover, with a typically narrowed neck above a rounded body and a footed pedestal. Describing a vessel as an "urn", as opposed to a vase or other terms, generally reflects its use rather than any particular shape or ...
. In most bromeliads, water collects readily in this urn and may provide
habitats In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical ...
for
frog A frog is any member of a diverse and largely Carnivore, carnivorous group of short-bodied, tailless amphibians composing the order (biology), order Anura (ανοὐρά, literally ''without tail'' in Ancient Greek). The oldest fossil "proto-f ...
s,
insect Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three pairs ...
s and, more useful for the plant,
diazotroph Diazotrophs are bacteria and archaea that fix gaseous nitrogen in the atmosphere into a more usable form such as ammonia. A diazotroph is a microorganism that is able to grow without external sources of fixed nitrogen. Examples of organisms that ...
ic (nitrogen-fixing) bacteria. In ''Brocchinia'', the urn is a specialised insect trap, with a loose, waxy lining and a population of digestive bacteria.


Flypaper traps

The flypaper trap utilises sticky mucilage or glue. The leaf of flypaper traps is studded with
mucilage Mucilage is a thick, gluey substance produced by nearly all plants and some microorganisms. These microorganisms include protists which use it for their locomotion. The direction of their movement is always opposite to that of the secretion of m ...
-secreting glands, which may be short (like those of the
butterwort ''Pinguicula'', commonly known as the butterworts, is a genus of carnivorous flowering plants in the family Lentibulariaceae. They use sticky, glandular leaves to lure, trap, and digest insects in order to supplement the poor mineral nutrition ...
s), or long and mobile (like those of many
sundew ''Drosera'', which is commonly known as the sundews, is one of the largest genera of carnivorous plants, with at least 194 species. 2 volumes. These members of the family Droseraceae lure, capture, and digest insects using stalked mucilaginou ...
s). Flypapers have evolved independently at least five times. There is evidence that some clades of flypaper traps have evolved from morphologically more complex traps such as pitchers. In the genus ''
Pinguicula ''Pinguicula'', commonly known as the butterworts, is a genus of carnivorous flowering plants in the family Lentibulariaceae. They use sticky, glandular leaves to lure, trap, and digest insects in order to supplement the poor mineral nutrition ...
'', the mucilage glands are quite short (
sessile Sessility, or sessile, may refer to: * Sessility (motility), organisms which are not able to move about * Sessility (botany), flowers or leaves that grow directly from the stem or peduncle of a plant * Sessility (medicine), tumors and polyps that ...
), and the leaf, while shiny (giving the genus its common name of '
butterwort ''Pinguicula'', commonly known as the butterworts, is a genus of carnivorous flowering plants in the family Lentibulariaceae. They use sticky, glandular leaves to lure, trap, and digest insects in order to supplement the poor mineral nutrition ...
'), does not appear carnivorous. However, this belies the fact that the leaf is an extremely effective trap of small flying insects (such as fungus gnats), and its surface responds to prey by relatively rapid growth. This thigmotropic growth may involve rolling of the leaf blade (to prevent rain from splashing the prey off the leaf surface) or dishing of the surface under the prey to form a shallow digestive pit. The
sundew ''Drosera'', which is commonly known as the sundews, is one of the largest genera of carnivorous plants, with at least 194 species. 2 volumes. These members of the family Droseraceae lure, capture, and digest insects using stalked mucilaginou ...
genus (''
Drosera ''Drosera'', which is commonly known as the sundews, is one of the largest genus, genera of carnivorous plants, with at least 194 species. 2 volumes. These members of the family Droseraceae lure, capture, and digest insects using stalked mucil ...
'') consists of over 100 species of active flypapers whose mucilage glands are borne at the end of long
tentacle In zoology, a tentacle is a flexible, mobile, and elongated organ present in some species of animals, most of them invertebrates. In animal anatomy, tentacles usually occur in one or more pairs. Anatomically, the tentacles of animals work main ...
s, which frequently grow fast enough in response to prey (
thigmotropism Thigmotropism is a directional growth movement which occurs as a mechanosensory response to a touch stimulus. Thigmotropism is typically found in twining plants and tendrils, however plant biologists have also found thigmotropic responses in flowe ...
) to aid the trapping process. The tentacles of ''D. burmanii'' can bend 180° in a minute or so. Sundews are extremely cosmopolitan and are found on all the continents except the
Antarctic The Antarctic ( or , American English also or ; commonly ) is a polar region around Earth's South Pole, opposite the Arctic region around the North Pole. The Antarctic comprises the continent of Antarctica, the Kerguelen Plateau and other ...
mainland. They are most diverse in
Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...
, the home to the large subgroup of pygmy sundews such as ''D. pygmaea'' and to a number of tuberous sundews such as ''D. peltata'', which form tubers that aestivate during the dry summer months. These species are so dependent on insect sources of nitrogen that they generally lack the enzyme
nitrate reductase Nitrate reductases are molybdoenzymes that reduce nitrate (NO) to nitrite (NO). This reaction is critical for the production of protein in most crop plants, as nitrate is the predominant source of nitrogen in fertilized soils. Types Euka ...
, which most plants require to assimilate soil-borne nitrate into organic forms. Similar to ''
Drosera ''Drosera'', which is commonly known as the sundews, is one of the largest genus, genera of carnivorous plants, with at least 194 species. 2 volumes. These members of the family Droseraceae lure, capture, and digest insects using stalked mucil ...
'' is the
Portuguese Portuguese may refer to: * anything of, from, or related to the country and nation of Portugal ** Portuguese cuisine, traditional foods ** Portuguese language, a Romance language *** Portuguese dialects, variants of the Portuguese language ** Portu ...
dewy pine, ''
Drosophyllum ''Drosophyllum'' ( , rarely ) is a genus of carnivorous plants containing the single species ''Drosophyllum lusitanicum'', commonly known as Portuguese sundew or dewy pine. In appearance, it is similar to the related genus ''Drosera'' (the sun ...
'', which differs from the sundews in being passive. Its leaves are incapable of rapid movement or growth. Unrelated, but similar in habit, are the Australian rainbow plants (''
Byblis In Greek mythology, Byblis or Bublis (Ancient Greek: Βυβλίς) was a daughter of Miletus. Her mother was either Tragasia, daughter of Celaenus; Parthenius, ''Erotica Pathemata'' 11 Cyanee, daughter of the river-god Meander, or Eidothea, d ...
''). ''Drosophyllum'' is unusual in that it grows under near-
desert A desert is a barren area of landscape where little precipitation occurs and, consequently, living conditions are hostile for plant and animal life. The lack of vegetation exposes the unprotected surface of the ground to denudation. About on ...
conditions; almost all other carnivores are either bog plants or grow in moist tropical areas. Recent molecular data (particularly the production of
plumbagin Plumbagin or 5-hydroxy-2-methyl-1,4-naphthoquinone is an organic compound with the chemical formula . It is regarded as a toxin and it is genotoxic and mutagenic. Plumbagin is a yellow dye,flypaper, '' Triphyophyllum peltatum'', a member of the
Dioncophyllaceae The Dioncophyllaceae are a family (biology), family of flowering plants consisting of three species of lianas native to the rainforests of western Africa. Their closest relatives are Ancistrocladaceae. Both families lie within a clade of mostly ...
, is closely related to ''Drosophyllum'' and forms part of a larger
clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...
of carnivorous and non-carnivorous plants with the
Droseraceae Droseraceae is a family of carnivorous flowering plants, also known as the sundew family. It consists of approximately 180 species in three extant genera. Representatives of the Droseraceae are found on all continents except Antarctica. Descr ...
, Nepenthaceae,
Ancistrocladaceae ''Ancistrocladus'' is a genus of woody lianas in the monotypic family ''Ancistrocladaceae''. The branches climb by twining other stems or by scrambling with hooked tips. They are found in the tropics of the Old World. Classification The APG II ...
and
Plumbaginaceae Plumbaginaceae is a family of flowering plants, with a cosmopolitan distribution. The family is sometimes referred to as the leadwort family or the plumbago family. Most species in this family are perennial herbaceous plants, but a few grow as ...
. This plant is usually encountered as a
liana A liana is a long- stemmed, woody vine that is rooted in the soil at ground level and uses trees, as well as other means of vertical support, to climb up to the canopy in search of direct sunlight. The word ''liana'' does not refer to a ta ...
, but in its juvenile phase, the plant is carnivorous. This may be related to a requirement for specific nutrients for flowering.


Snap traps

The only two active snap traps—the
Venus flytrap The Venus flytrap (''Dionaea muscipula'') is a carnivorous plant native to subtropical wetlands on the East Coast of the United States in North Carolina and South Carolina. It catches its prey—chiefly insects and arachnids—with a trapping ...
(''
Dionaea muscipula The Venus flytrap (''Dionaea muscipula'') is a carnivorous plant native to subtropical wetlands on the East Coast of the United States in North Carolina and South Carolina. It catches its prey—chiefly insects and arachnids—with a trapping ...
'') and the
waterwheel plant ''Aldrovanda vesiculosa'', commonly known as the waterwheel plant, is the sole extant species in the flowering plant genus ''Aldrovanda'' of the family Droseraceae. The plant captures small aquatic invertebrates using traps similar to those of ...
(''
Aldrovanda ''Aldrovanda'' is a genus of carnivorous plants encompassing one extant species (''Aldrovanda vesiculosa'', the waterwheel plant) and numerous extinct taxa. The genus is named in honor of the Italian naturalist Ulisse Aldrovandi, the founder of ...
vesiculosa'')—had a
common ancestor Common descent is a concept in evolutionary biology applicable when one species is the ancestor of two or more species later in time. All living beings are in fact descendants of a unique ancestor commonly referred to as the last universal comm ...
with the snap trap adaptation, which had evolved from an ancestral lineage that utilized flypaper traps. Their trapping mechanism has also been described as a "mouse trap", "bear trap" or "man trap", based on their shape and rapid movement. However, the term ''snap trap'' is preferred as other designations are misleading, particularly with respect to the intended prey. ''Aldrovanda'' is aquatic and specialized in catching small invertebrates; ''Dionaea'' is terrestrial and catches a variety of arthropods, including spiders. The traps are very similar, with leaves whose terminal section is divided into two lobes, hinged along the midrib. Trigger hairs (three on each lobe in ''Dionaea muscipula'', many more in the case of ''Aldrovanda'') inside the trap lobes are sensitive to touch. When a trigger hair is bent, stretch-gated
ion channel Ion channels are pore-forming membrane proteins that allow ions to pass through the channel pore. Their functions include establishing a resting membrane potential, shaping action potentials and other electrical signals by gating the flow of io ...
s in the
membranes A membrane is a selective barrier; it allows some things to pass through but stops others. Such things may be molecules, ions, or other small particles. Membranes can be generally classified into synthetic membranes and biological membranes. Bi ...
of cells at the base of the trigger hair open, generating an
action potential An action potential occurs when the membrane potential of a specific cell location rapidly rises and falls. This depolarization then causes adjacent locations to similarly depolarize. Action potentials occur in several types of animal cells, ...
that propagates to cells in the midrib. These cells respond by pumping out ions, which may either cause water to follow by osmosis (collapsing the cells in the midrib) or cause rapid
acid growth Acid growth refers to the ability of plant cells and plant cell walls to elongate or expand quickly at low (acidic) pH. The cell wall needs to be modified in order to maintain the turgor pressure. This modification is controlled by plant hormones l ...
. The mechanism is still debated, but in any case, changes in the shape of cells in the midrib allow the lobes, held under tension, to snap shut, flipping rapidly from convex to concave and interring the prey. This whole process takes less than a second. In the Venus flytrap, closure in response to raindrops and blown-in debris is prevented by the leaves having a simple memory: for the lobes to shut, two
stimuli A stimulus is something that causes a physiological response. It may refer to: * Stimulation ** Stimulus (physiology), something external that influences an activity ** Stimulus (psychology), a concept in behaviorism and perception * Stimulus (eco ...
are required, 0.5 to 30 seconds apart. According to a recent study, calcium molecules move dynamically within the cells of the plant's leaves when a carnivorous plant touches live prey. Changing calcium levels make leaves move to catch prey, likely by producing more hormones related to defense. The snapping of the leaves is a case of
thigmonasty Thigmonasty or seismonasty is the nastic movement, nastic response of a plant or fungus to touch or vibration. Conspicuous examples of thigmonasty include many species in the Fabaceae, leguminous family (biology), subfamily Mimosoideae, active carn ...
(undirected movement in response to touch). Further stimulation of the lobe's internal surfaces by the struggling insects causes the lobes to close even tighter (
thigmotropism Thigmotropism is a directional growth movement which occurs as a mechanosensory response to a touch stimulus. Thigmotropism is typically found in twining plants and tendrils, however plant biologists have also found thigmotropic responses in flowe ...
), sealing the lobes hermetically and forming a
stomach The stomach is a muscular, hollow organ in the gastrointestinal tract of humans and many other animals, including several invertebrates. The stomach has a dilated structure and functions as a vital organ in the digestive system. The stomach i ...
in which digestion occurs over a period of one to two weeks. Once this process is triggered, it cannot be reversed and requires more stimulation to trigger the next steps. Leaves can be reused three or four times before they become unresponsive to stimulation, depending on the growing conditions.


Bladder traps

Bladder traps are exclusive to the genus ''
Utricularia ''Utricularia'', commonly and collectively called the bladderworts, is a genus of carnivorous plants consisting of approximately 233 species (precise counts differ based on classification opinions; a 2001 publication lists 215 species).Salmon, Br ...
'', or
bladderwort ''Utricularia'', commonly and collectively called the bladderworts, is a genus of carnivorous plants consisting of approximately 233 species (precise counts differ based on classification opinions; a 2001 publication lists 215 species).Salmon, Br ...
s. The bladders ( vesiculae) pump
ion An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by conve ...
s out of their interiors. Water follows by
osmosis Osmosis (, ) is the spontaneous net movement or diffusion of solvent molecules through a selectively-permeable membrane from a region of high water potential (region of lower solute concentration) to a region of low water potential (region of ...
, generating a partial
vacuum A vacuum is a space devoid of matter. The word is derived from the Latin adjective ''vacuus'' for "vacant" or "void". An approximation to such vacuum is a region with a gaseous pressure much less than atmospheric pressure. Physicists often dis ...
inside the bladder. The bladder has a small opening, sealed by a hinged door. In aquatic species, the door has a pair of long trigger hairs. Aquatic invertebrates such as ''
Daphnia ''Daphnia'' is a genus of small planktonic crustaceans, in length. ''Daphnia'' are members of the order Anomopoda, and are one of the several small aquatic crustaceans commonly called water fleas because their saltatory swimming style resembl ...
'' touch these hairs and deform the door by
lever A lever is a simple machine consisting of a beam or rigid rod pivoted at a fixed hinge, or ''fulcrum''. A lever is a rigid body capable of rotating on a point on itself. On the basis of the locations of fulcrum, load and effort, the lever is div ...
action, releasing the vacuum. The invertebrate is sucked into the bladder, where it is digested. Many species of ''
Utricularia ''Utricularia'', commonly and collectively called the bladderworts, is a genus of carnivorous plants consisting of approximately 233 species (precise counts differ based on classification opinions; a 2001 publication lists 215 species).Salmon, Br ...
'' (such as ''U. sandersonii'') are
terrestrial Terrestrial refers to things related to land or the planet Earth. Terrestrial may also refer to: * Terrestrial animal, an animal that lives on land opposed to living in water, or sometimes an animal that lives on or near the ground, as opposed to ...
, growing in waterlogged soil, and their trapping mechanism is triggered in a slightly different manner. Bladderworts lack
root In vascular plants, the roots are the organs of a plant that are modified to provide anchorage for the plant and take in water and nutrients into the plant body, which allows plants to grow taller and faster. They are most often below the sur ...
s, but terrestrial species have anchoring stems that resemble roots. Temperate aquatic bladderworts generally die back to a resting turion during the winter months, and ''U. macrorhiza'' appears to regulate the number of bladders it bears in response to the prevailing nutrient content of its habitat.


Lobster-pot traps

A lobster-pot trap is a chamber that is easy to enter, and whose exit is either difficult to find or obstructed by inward-pointing bristles. Lobster pots are the trapping mechanism in ''
Genlisea ''Genlisea'' ( ) is a genus of carnivorous plants also known as corkscrew plants. The 30 or so species grow in wet terrestrial to semi-aquatic environments distributed throughout Africa and Central and South America. The plants use highly modifi ...
'', the corkscrew plants. These plants appear to specialise in aquatic
protozoa Protozoa (singular: protozoan or protozoon; alternative plural: protozoans) are a group of single-celled eukaryotes, either free-living or parasitic, that feed on organic matter such as other microorganisms or organic tissues and debris. Histo ...
. A ''Y''-shaped modified leaf allows prey to enter but not exit. Inward-pointing hairs force the prey to move in a particular direction. Prey entering the spiral entrance that coils around the upper two arms of the ''Y'' are forced to move inexorably towards a stomach in the lower arm of the ''Y'', where they are digested. Prey movement is also thought to be encouraged by water movement through the trap, produced in a similar way to the vacuum in bladder traps, and probably evolutionarily related to it. Outside of ''Genlisea'', features reminiscent of lobster-pot traps can be seen in ''
Sarracenia psittacina ''Sarracenia psittacina'', also known as the parrot pitcherplant, is a carnivorous plant in the genus ''Sarracenia''. Like all the ''Sarracenia'', it is native to North America, in the Southeastern United States. ''Sarracenia psittacina'' emp ...
'', '' Darlingtonia californica'', and, some horticulturalists argue, ''
Nepenthes aristolochioides ''Nepenthes aristolochioides'' is a tropical pitcher plant endemic to Sumatra, where it grows at elevations of 1800–2500 m above sea level. It has an extremely unusual pitcher morphology, having an almost vertical opening to its traps. ...
''.


Combination traps

The trapping mechanism of the sundew '' Drosera glanduligera'' combines features of both flypaper and snap traps; it has been termed a ''catapult-flypaper trap''. However, this is not the only combination traps. '' Nepenthes jamban'' is a combination of pitfall and flypaper traps because it has a sticky pitcher fluid. Most Sumatran nepenthes, like ''N. inermis'', also have this method. For example, '' N. dubia'' and '' N. flava'' also use this method.


Borderline carnivores

To be defined as carnivorous, a plant must first exhibit an adaptation of some trait specifically for the attraction, capture, or digestion of prey. Only one trait needs to have evolved that fits this adaptive requirement, as many current carnivorous plant genera lack some of the above-mentioned attributes. The second requirement is the ability to absorb nutrients from dead prey and gain a fitness advantage from the integration of these derived nutrients (mostly
amino acid Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha am ...
s and
ammonium The ammonium cation is a positively-charged polyatomic ion with the chemical formula or . It is formed by the protonation of ammonia (). Ammonium is also a general name for positively charged or protonated substituted amines and quaternary a ...
ions) either through increased growth or pollen and/or seed production. However, plants that may opportunistically utilise nutrients from dead animals without specifically seeking and capturing fauna are excluded from the carnivorous definition. The second requirement also differentiates carnivory from defensive plant characteristics that may kill or incapacitate insects without the advantage of nutrient absorption. Due to the observation that many currently classified carnivores lack digestive enzymes for breaking down nutrients and instead rely upon mutualistic and symbiotic relationships with bacteria, ants, or insects, this adaptation has been added to the carnivorous definition. Despite this, there are cases where plants appear carnivorous, in that they fulfill some of the above definition, but are not truly carnivorous. Some botanists argue that there is a spectrum of carnivory found in plants: from completely non-carnivorous plants like
cabbage Cabbage, comprising several cultivars of ''Brassica oleracea'', is a leafy green, red (purple), or white (pale green) biennial plant grown as an annual vegetable crop for its dense-leaved heads. It is descended from the wild cabbage ( ''B.&nb ...
s, to borderline carnivores, to unspecialised and simple traps, like ''Heliamphora'', to extremely specialised and complex traps, like that of the Venus flytrap. A possible carnivore is the genus ''
Roridula ''Roridula'' (; from Latin ''roridus'' "dewy") is a genus of evergreen, insect-trapping shrubs, with two species, of about 1⅓–2 m (4–6⅔ ft). It is the only genus in the family Roridulaceae. It has thin, woody, shyly branching, upright, in ...
''; the plants in this genus produce sticky leaves with resin-tipped glands and look extremely similar to some of the larger sundews. However, they do not directly benefit from the insects they catch. Instead, they form a mutualistic
symbiosis Symbiosis (from Greek , , "living together", from , , "together", and , bíōsis, "living") is any type of a close and long-term biological interaction between two different biological organisms, be it mutualistic, commensalistic, or parasit ...
with species of
assassin bug The Reduviidae are a large cosmopolitan family of the order Hemiptera (true bugs). Among the Hemiptera and together with the Nabidae almost all species are terrestrial ambush predators: most other predatory Hemiptera are aquatic. The main exampl ...
(genus ''
Pameridea ''Pameridea'' is a genus of insects comprising two species, ''P. roridulae'' and ''P. marlothii'', that live in symbiotic relationships with carnivorous plants in the genus ''Roridula''. ''Pameridea marlothii'' only occurs on ''R. dentata'', w ...
''), which eat the trapped insects. The plant benefits from the nutrients in the bugs'
feces Feces ( or faeces), known colloquially and in slang as poo and poop, are the solid or semi-solid remains of food that was not digested in the small intestine, and has been broken down by bacteria in the large intestine. Feces contain a relati ...
. By some definitions this would still constitute botanical carnivory. A number of species in the
Martyniaceae Martyniaceae is a family of flowering plants in the Lamiales order that are restricted to the Americas. The family was included in Pedaliaceae in the Cronquist system (under order Scrophulariales) but is recognized as a separate family by the An ...
(previously
Pedaliaceae Pedaliaceae, the pedalium family or sesame family, is a flowering plant family classified in the order Lamiales. The family includes sesame (''Sesamum indicum''), the source of sesame seeds. It comprises 13 genera and approximately 70 spec ...
), such as ''
Ibicella lutea ''Ibicella lutea'' (; syn. ''Martynia lutea, Proboscidea lutea'') is a species of flowering plant known by the common name yellow unicorn-plant. It grows in dry conditions, such as those in desert regions. It is native to South America, but has ...
'', have sticky leaves that trap insects. However, these plants have not been shown conclusively to be carnivorous. Likewise, the seeds of
Shepherd's Purse ''Capsella bursa-pastoris'', known as shepherd's purse because of its triangular flat fruits, which are purse-like, is a small annual and ruderal flowering plant in the mustard family (Brassicaceae). It is native to eastern Europe and Asia minor, ...
, urns of ''
Paepalanthus bromelioides ''Paepalanthus bromelioides'' is a species in the flowering plant family Eriocaulaceae. This family is placed in the Poales, close to the Bromeliaceae, whose morphology this genus shares. ''Paepalanthus bromelioides'' is native to Cerrado, ...
'',
bract In botany, a bract is a modified or specialized leaf, especially one associated with a reproductive structure such as a flower, inflorescence axis or cone scale. Bracts are usually different from foliage leaves. They may be smaller, larger, or of ...
s of '' Passiflora foetida'', and flower stalks and
sepal A sepal () is a part of the flower of angiosperms (flowering plants). Usually green, sepals typically function as protection for the flower in bud, and often as support for the petals when in bloom., p. 106 The term ''sepalum'' was coined b ...
s of triggerplants (''Stylidium'') appear to trap and kill insects, but their classification as carnivores is contentious. Two genera of liverwort, '' Colura'' and ''
Pleurozia ''Pleurozia'' is the only genus of liverworts in the family Pleuroziaceae, which is now classified in its own order Pleuroziales, but was previously included in a broader circumscription of the Jungermanniales. The genus includes twelve species ...
'', have sac-shaped leaves that trap and kill
ciliate The ciliates are a group of alveolates characterized by the presence of hair-like organelles called cilia, which are identical in structure to flagellum, eukaryotic flagella, but are in general shorter and present in much larger numbers, with a ...
s and may digest them.


Digestion

Specialized multicellular secretion glands produce digestive fluid that smother, kill, digest prey and make a solution to assimilate released nutrients. Saccharides are often found in plants that have adhesive traps or plants that use viscous secretion to retain captured prey. The digestion fluid is often nutrient poor and has ions K, Na, Ca and Mg (for species in the ''Nepenthes'' genera for example), along with numerous proteins which vary across genera. Peroxidases are also involved for some species. The body of the prey is decomposed by a cocktail of hydrolytic enzymes which are stored in sub-cellular compartments or synthesized over and over as needed. Proteins of digestive fluid include proteases, chitinases (partly destroy exoskeleton of insects), phosphatases, and nucleases.


Evolution


General pattern of independent development in multiple lineages

Charles Darwin spent 16 years growing carnivorous plants, experimenting with them in the greenhouse of his home in
Kent Kent is a county in South East England and one of the home counties. It borders Greater London to the north-west, Surrey to the west and East Sussex to the south-west, and Essex to the north across the estuary of the River Thames; it faces ...
,
Down House Down House is the former home of the English naturalist Charles Darwin and his family. It was in this house and garden that Darwin worked on his theory of evolution by natural selection, which he had conceived in London before moving to Down ...
. In his pioneering book ''Insectivorous Plants'' (1875) Darwin concluded that carnivory in plants was convergent, writing that carnivorous genera ''
Utricularia ''Utricularia'', commonly and collectively called the bladderworts, is a genus of carnivorous plants consisting of approximately 233 species (precise counts differ based on classification opinions; a 2001 publication lists 215 species).Salmon, Br ...
'' and ''
Nepenthes ''Nepenthes'' () is a genus of carnivorous plants, also known as tropical pitcher plants, or monkey cups, in the monotypic family Nepenthaceae. The genus includes about 170 species, and numerous natural and many cultivated hybrids. They are mos ...
'' were not "at all related to the arnivorous family
Droseraceae Droseraceae is a family of carnivorous flowering plants, also known as the sundew family. It consists of approximately 180 species in three extant genera. Representatives of the Droseraceae are found on all continents except Antarctica. Descr ...
".  This remained a subject of debate for over a century. In 1960, Leon Croizat concluded that carnivory was
monophyletic In cladistics for a group of organisms, monophyly is the condition of being a clade—that is, a group of taxa composed only of a common ancestor (or more precisely an ancestral population) and all of its lineal descendants. Monophyletic gro ...
, and placed all the carnivorous plants together at the base of the angiosperms.  Molecular studies over the past 30 years have led to a wide consensus that Darwin was correct, with studies showing that carnivory evolved at least six times in the angiosperms, and that trap designs such as pitcher traps and flypaper traps are analogous rather than homologous. Researchers using molecular data have concluded that carnivory evolved independently in the
Poales The Poales are a large order of flowering plants in the monocotyledons, and includes families of plants such as the grasses, bromeliads, and sedges. Sixteen plant families are currently recognized by botanists to be part of Poales. Descriptio ...
(''
Brocchinia ''Brocchinia'' is a genus of the botanical family Bromeliaceae, and is the sole genus of the subfamily Brocchinioideae, containing 20 species. The genus is named for Giovanni Battista Brocchi, Italian naturalist (1772–1826). ''Brocchinia'' sp ...
'' and ''
Catopsis ''Catopsis'' is a genus in the botanical family Bromeliaceae, subfamily Tillandsioideae. The genus name is from the Greek “kata” (hanging down) and “opsis” (appearance). ''Catopsis'' is a genus of plants widespread across much of Latin A ...
'' in the
Bromeliaceae The Bromeliaceae (the bromeliads) are a family of monocot Monocotyledons (), commonly referred to as monocots, (Lilianae ''sensu'' Chase & Reveal) are grass and grass-like flowering plants (angiosperms), the seeds of which typically contain o ...
), the
Caryophyllales Caryophyllales ( ) is a diverse and heterogeneous order of flowering plants that includes the cacti, carnations, amaranths, ice plants, beets, and many carnivorous plants. Many members are succulent, having fleshy stems or leaves. The betalai ...
(
Droseraceae Droseraceae is a family of carnivorous flowering plants, also known as the sundew family. It consists of approximately 180 species in three extant genera. Representatives of the Droseraceae are found on all continents except Antarctica. Descr ...
, Nepenthaceae, Drosophyllaceae,
Dioncophyllaceae The Dioncophyllaceae are a family (biology), family of flowering plants consisting of three species of lianas native to the rainforests of western Africa. Their closest relatives are Ancistrocladaceae. Both families lie within a clade of mostly ...
), the
Oxalidales Oxalidales is an order of flowering plants, included within the rosid subgroup of eudicots. Compound leaves are common in Oxalidales and the majority of the species in this order have five or six sepals and petals. The following families are typic ...
(''
Cephalotus ''Cephalotus'' ( or ; Greek: ''κεφαλή'' "head", and ''οὔς''/''ὠτός'' "ear", to describe the head of the anthers) is a genus which contains one species, ''Cephalotus follicularis'' the Albany pitcher plant, a small carnivorous pi ...
''), the
Ericales The Ericales are a large and diverse order of dicotyledons. Species in this order have considerable commercial importance including for Camellia sinensis, tea, persimmon, blueberry, kiwifruit, Brazil nuts, Argania, argan, and azalea. The order i ...
(
Sarraceniaceae Sarraceniaceae are a family of pitcher plants, belonging to order Ericales (previously Nepenthales). The family comprises three extant genera: ''Sarracenia'' (North American pitcher plants), '' Darlingtonia'' (the cobra lily or California pitc ...
and Roridulaceae), and twice in the
Lamiales The order Lamiales (also known as the mint order) are an order in the asterid group of dicotyledonous flowering plants. It includes about 23,810 species, 1,059 genera, and is divided into about 25 families. These families include Acanthaceae, Bi ...
(
Lentibulariaceae Lentibulariaceae is a family of carnivorous plants containing three genera: ''Genlisea'', the corkscrew plants; ''Pinguicula'', the butterworts; and ''Utricularia'', the bladderworts. The genera ''Polypompholyx'' (two species of pink petticoats ...
and independently in
Byblidaceae ''Byblis'' ( ) is a small genus of carnivorous plants, sometimes termed the rainbow plants for the attractive appearance of their mucilage-covered leaves in bright sunshine. Native to Australia and New Guinea, it is the only genus in the f ...
).  The oldest evolution of an existing carnivory lineage has been dated to 85.6 million years ago, with the most recent being ''
Brocchinia reducta ''Brocchinia reducta'' is one of a few carnivorous plant, carnivorous Bromeliaceae, bromeliads. It is native to southern Venezuela, Brazil, Colombia, and Guyana, and is found in nutrient-poor soil. ''B. reducta'' adapts to different environments ...
'' in the Bromeliaceae estimated at only 1.9 mya. The evolution of carnivorous plants is obscured by the paucity of their
fossil record A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in ...
. Very few
fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...
s have been found, and then usually only as
seed A seed is an embryonic plant enclosed in a protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiospe ...
or
pollen Pollen is a powdery substance produced by seed plants. It consists of pollen grains (highly reduced microgametophytes), which produce male gametes (sperm cells). Pollen grains have a hard coat made of sporopollenin that protects the gametophyt ...
. Carnivorous plants are generally herbs, and their traps are produced by
primary growth In botany, secondary growth is the growth that results from cell division in the cambium (botany), cambia or lateral meristems and that causes the Plant stem, stems and roots to thicken, while primary growth is growth that occurs as a result of ...
. They generally do not form readily fossilisable structures such as thick bark or wood. Researchers are increasingly using genome sequencing technology to examine the development of carnivorous species and relationships between them. Genetic evidence suggests that carnivory developed by co-opting and repurposing existing genes which had established functions in flowering plants, rather than by "hijacking" genes from other types of organisms.


Adaption to extreme habitats

Most carnivorous plants live in habitats with high light, waterlogged soils, and extremely low soil nitrogen and phosphorus, producing the ecological impetus to derive nitrogen from an alternate source. High-light environments allowed for the trade-off between photosynthetic leaves and photosynthetically-inefficient, prey-capturing traps. To compensate for the photosynthetically-inefficient material, the nutrients obtained through carnivory would need to increase photosynthesis by investing in more leaf mass (i.e. growth). Consequently, when there is a shortage of nutrients, sufficient light and water, the capture and digestion of prey has the greatest impact on photosynthetic gains, thus favoring the evolution of plant adaptations which allowed for more effective, efficient carnivory. Due to the required energy and resource allocations for carnivorous adaptations (e.g. the production of lures, digestive enzymes, modified leaf structures, and the decreased rate of photosynthesis over total leaf area), some authors argue that carnivory is an evolutionary "last resort" when nitrogen and phosphorus are extremely limited in an ecosystem.


Inferences from trap mechanism

Despite meager fossil evidence, much can be deduced from the structure of current traps and their ecological interactions. It is widely believed that carnivory evolved under extremely nutrient-poor conditions, leading to a cost-benefit model for botanical carnivory. Cost-benefit models are used under the assumption that there is a set amount of potential energy available to an organism, which leads to trade-offs wherein energy is allocated to certain functions to maximize competitive ability and fitness. For carnivory, the trait could only evolve if the increase in nutrients from capturing prey exceeded the cost of investment in carnivorous adaptations. Pitfall traps are derived from rolled leaves, which evolved several independent times through convergent evolution. The vascular tissues of ''Sarracenia'' is a case in point. The keel along the front of the trap contains a mixture of leftward- and rightward-facing
vascular bundles A vascular bundle is a part of the transport system in vascular plants. The transport itself happens in the stem, which exists in two forms: xylem and phloem. Both these tissues are present in a vascular bundle, which in addition will includ ...
, as would be predicted from the fusion of the edges of an
adaxial {{Short pages monitor In 1789, Erasmus Darwin described ''Drosera'' in the second part of his poem ''
The Botanic Garden ''The Botanic Garden'' (1791) is a set of two poems, ''The Economy of Vegetation'' and ''The Loves of the Plants'', by the British poet and naturalist Erasmus Darwin. ''The Economy of Vegetation'' celebrates technological innovation and scien ...
'': However, Erasmus Darwin and others of his generation assumed that the "wonderful contrivance of carnivorous plants were solely defense mechanisms to “prevent various insects from plundering the honey, or devouring the seed”. They realized that the plants were killing insects, but did not understand why. Erasmus Darwin's son,
Charles Darwin Charles Robert Darwin ( ; 12 February 1809 – 19 April 1882) was an English naturalist, geologist, and biologist, widely known for his contributions to evolutionary biology. His proposition that all species of life have descended fr ...
, and grandson,
Francis Darwin Sir Francis "Frank" Darwin (16 August 1848 – 19 September 1925) was a British botanist. He was the third son of the naturalist and scientist Charles Darwin. Biography Francis Darwin was born in Down House, Downe, Kent in 1848. He was the ...
, spent many years studying carnivorous plants. Charles Darwin recognized and described the significance of plant carnivory for nutrition. Possibly the earliest published account of a
man-eating plant A man-eating plant is a legendary carnivorous plant large enough to kill and consume a human or other large animal. Various such myths and fictional tales exist around the world. The Madagascar tree The earliest known report of a man-eating plan ...
was a literary fabrication that first appeared in 1874. The story of ''Crinoida dajeeana'', also known as the Devil Tree of Madagascar or Man-Eating Tree of Madagascar, first appeared in the daily edition of the ''
New York World The ''New York World'' was a newspaper published in New York City from 1860 until 1931. The paper played a major role in the history of American newspapers. It was a leading national voice of the Democratic Party. From 1883 to 1911 under publi ...
'' on 26 April 1874, and again in the weekly edition two days later. It purported to be from a German
explorer Exploration refers to the historical practice of discovering remote lands. It is studied by geographers and historians. Two major eras of exploration occurred in human history: one of convergence, and one of divergence. The first, covering most ...
named "Karl Leche" (also spelled as Karl or Carl Liche in later accounts), who described seeing a woman fed to a tree as a
sacrifice Sacrifice is the offering of material possessions or the lives of animals or humans to a deity as an act of propitiation or worship. Evidence of ritual animal sacrifice has been seen at least since ancient Hebrews and Greeks, and possibly exi ...
by the "little known but cruel" "Mkodo tribe" of
Madagascar Madagascar (; mg, Madagasikara, ), officially the Republic of Madagascar ( mg, Repoblikan'i Madagasikara, links=no, ; french: République de Madagascar), is an island country in the Indian Ocean, approximately off the coast of East Africa ...
. Authorship of the fantastical story would later be attributed by Frederick Maxwell Somers to one Edmund Spencer in the August 1888 issue of the magazine ''Current Literature''. The story was reprinted widely, appearing as far away as the ''
South Australian Register ''The Register'', originally the ''South Australian Gazette and Colonial Register'', and later ''South Australian Register,'' was South Australia's first newspaper. It was first published in London in June 1836, moved to Adelaide in 1837, and f ...
'' in 1881, where it was accompanied by an illustration of a tree consuming a woman. The account has been debunked as pure myth, and Dr. Liche, the Mkodos, and the tree itself were all fabrications. ''Crinoida dajeeana'' notwithstanding, carnivorous plants are credited with widely entering the popular imagination through the nonfiction publications of
Charles Darwin Charles Robert Darwin ( ; 12 February 1809 – 19 April 1882) was an English naturalist, geologist, and biologist, widely known for his contributions to evolutionary biology. His proposition that all species of life have descended fr ...
. '' Insectivorous Plants'' (1875), followed by ''
The Power of Movement in Plants ''The Power of Movement in Plants'' is a book by Charles Darwin on phototropism and other types of movement in plants. This book continues his work in producing evidence for his theory of natural selection. As it was one of his last books, fol ...
'' (1880), challenged the idea of a what a plant was and what it was capable of doing, and inspired authors like
Arthur Conan Doyle Sir Arthur Ignatius Conan Doyle (22 May 1859 – 7 July 1930) was a British writer and physician. He created the character Sherlock Holmes in 1887 for ''A Study in Scarlet'', the first of four novels and fifty-six short stories about Ho ...
to imagine enormous and sometimes mobile man-eaters. Doyle modeled the sticky end of a character in "The American’s Tale" (1880) on a venus flytrap. H.G. Wells imagined a tentacular blood-sucking plant in "The Flowering of the Strange Orchid" (1894). Since then, carnivorous plants have been the subject of popular interest and exposition, much of it highly inaccurate. Typically, these fictional depictions include exaggerated characteristics, such as enormous size or possession of abilities beyond the realm of reality, and can be viewed as a kind of
artistic license Artistic license (alongside more contextually-specific derivative terms such as poetic license, historical license, dramatic license, and narrative license) refers to deviation from fact or form for artistic purposes. It can include the alterat ...
. In a 1939 pamphlet on carnivorous plants written for the Field Museum, Sophia Prior recounts the Man-Eating Tree of Madagascar and other "stories of vegetable monsters". She dismisses them all as fables, and notes that they are invariably set in locales that are "indefinite" and "difficult of access". Fictional carnivorous plants have been featured in books, movies, television series, and video games. Some, such as the
mockumentary A mockumentary (a blend of ''mock'' and ''documentary''), fake documentary or docu-comedy is a type of film or television show depicting fictional events but presented as a documentary. These productions are often used to analyze or comment on c ...
''
The Hellstrom Chronicle ''The Hellstrom Chronicle'' is an American film released in 1971 which combines elements of documentary, science fiction, horror and apocalyptic prophecy to present a gripping satirical depiction of the struggle for survival between humans and i ...
'' (1971), use accurate depictions of carnivorous plants for cinematic purposes, while others depend more heavily on imagination. Two of the most famous examples of fictional carnivorous plants in popular culture are the
triffid The triffid is a fictional tall, mobile, carnivorous plant species, created by John Wyndham in his 1951 novel ''The Day of the Triffids'', which has since been adapted for film and television. The word "triffid" has become a common reference ...
s of
John Wyndham John Wyndham Parkes Lucas Beynon Harris (; 10 July 1903 – 11 March 1969) was an English science fiction writer best known for his works published under the pen name John Wyndham, although he also used other combinations of his names ...
's 1951 novel ''
The Day of the Triffids ''The Day of the Triffids'' is a 1951 post-apocalyptic novel by the English science fiction author John Wyndham. After most people in the world are blinded by an apparent meteor shower, an aggressive species of plant starts killing people. Al ...
'' and Audrey, Jr./II, the man-eating plant in the 1960s
black comedy Black comedy, also known as dark comedy, morbid humor, or gallows humor, is a style of comedy that makes light of subject matter that is generally considered taboo, particularly subjects that are normally considered serious or painful to discus ...
''
The Little Shop of Horrors ''The Little Shop of Horrors'' is a 1960 American horror comedy film directed by Roger Corman. Written by Charles B. Griffith, the film is a farce about an inadequate florist's assistant who cultivates a plant that feeds on human blood. The fi ...
'' and its subsequent stage musical adaptation.


References


Further reading

* * * *


External links


Carnivorous Plant Database
provides an up-to-date, searchable database of all the published species of carnivorous plants.

at Sarracenia.com

* ttp://www.botany.org/carnivorous_plants/ Botanical Society of America - Carnivorous Plants Online
Inner World of Carnivorous Plants from the John Innes Centre

Time Lapse Videos of Carnivorous Plants
National Geographic ''National Geographic'' (formerly the ''National Geographic Magazine'', sometimes branded as NAT GEO) is a popular American monthly magazine published by National Geographic Partners. Known for its photojournalism, it is one of the most widely ...
{{Authority control Articles containing video clips