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|Carnivorous Plants at a Glance|
|by Makoto Honda|
Carnivorous Plants / Insectivorous Plants in the Wilderness Online Carnivorous Plants Photography Book.- Exploring Their Natural Habitats
Updated : 2007-11-03 Carnivorous Plants at a Glance
The idea that some plants are carnivorous may sound strange. Plants are eaten by herbivores and herbivores in turn are eaten by carnivores - a hierarchy of the food chain. History shows that there was some resistance on the part of early botanists to accept the notion that some plants had indeed evolved to catch and digest animals for their nutritional needs. There are places in the world where the soil is poor and plants cannot obtain enough nutrients through the root to sustain their growth. This environmental stress has given rise to a habit quite eccentric in the plant kingdom of our planet. It is in such mineral-poor environments that the plants that have adopted carnivory can be found. There are some 600 species of carnivorous plants recognized today, representing 12 families of angiosperm classification.
The family Bromeliaceae contains some 50 genera. Three species, two in Brocchinia and one in Catopsis, have recently been recognized as carnivorous (Brocchinia reducta, Brocchinia hectioides and Catopsis berteroniana) It is quite conceivable that the list of carnivorous bromeliads will get longer.
The tightly overlapping leaf bases form a tank that retains water. The upper portion of the leaf is waxy to cause the insect to lose its foothold and fall. Both adaxial (upper) and abaxial (lower) surfaces of the lower portion of the leaf are capable of absorbing nutrients. Unlike typical bromeliads, Brocchinia grows in a wet, acidic soil in full sun. The leaves of B. reducta assume a light yellow color in their native Guiana Highlands. The larger of the two, Brocchinia hectioides, grows to 2 m in height.
Catopsis contains 25 species. One species, C. berteroniana, has been shown to exhibit a primitive carnivorous habit.
Paepalanthus is a large genus containing some 600 species mainly from South America, of which only one, P. bromelioides, has recently been recognized as a primitive carnivore by Figueira, et al. (1994), the latest addition to our growing list of carnivorous angiosperms. There are reports of other species in the genus exhibiting similar characteristics.
The plant is a monocot native to Brazil, only found in Cipo National Park, at an elevation of 800-1200 m, in the state of Minas Gerais. The plant radiates long, flat leaves from a short stem. As in Brocchinia, its tightly overlapping leaves create a tank at the rosette center, retaining some acidic water. Ultraviolet attraction of the leaf is suspected to allure prey. Insects fall in the liquid and get digested. There is no report of enzyme secretions by the plant, but the glands exist on the leaf surface that allow the absorption of the product of digestion by bacteria.
There are about 150 species of sundews worldwide over both the Southern and Northern Hemispheres. By far, the heaviest concentration of the species occurs in Australia -- particularly South Australia and the southern part of Western Australia -- with nearly 50 endemic species of sundews in this continent alone. The southern part of Africa is also known for a large number of sundew species. Seven species grow in the continental United States. See Description for more.
Probably the most famous of all carnivorous plants because of its swift movement of trap leaves, the Venus flytrap is endemic to the Atlantic coastal plain of North America, where it is highly localized to southeastern North Carolina and the adjacent northeastern South Carolina within a 100km radius around the city of Wilmington on the N.C. coast.
The plants are typically found on a moist surface in the open pine tree forest, sometimes on a thick mat of sphagnum moss, sometimes right on the white sand surface, often in company of other carnivorous plants in the area such as sundews and terrestrial bladderworts. See Description for more.
The trap, corresponding to the leaf blade, is twisted to the left about its midrib almost 80 degrees, and then the midrib of the trap is bent to the right 60 degrees. The end result of this seemingly convoluted geometric manipulations of trap posture is that each set of traps in a given whorl more or less radially face outwards. The trap portion, which is barely 5 mm long, is almost translucent and appears like a miniature clamshell. Each lobe has numerous tiny teeth along the slightly folded-in margin. When the trap is set, the lobes are wide open, waiting for an unsuspecting prey to stop by.
Each lobe is divided into two zones: The marginal zone and the central zone. Each zone is further divided into 3 regions.
The marginal zone is very thin, formed of two layers of cells except at the rim. The outer region (the rim) is composed of one line of cells having a short tooth-like projection. This forms miniature teeth along the trap margin. The quadrifid region below is where many quadrifid glands are found buried on the inner surface. The outer surface bears small er, normally two-armed, glands. Further below is the hairless region where only two-armed glands (bifids) are found on the outer surface.
The central zone, thicker than the marginal zone, is three-cell layered and forms the digestive cavity during the narrowing phase. The digestive region is where numerous small sessile glands are found on the inner surface along with 15 or so thin trigger hairs scattered among the glands. Two-armed glands are found on the outer surface. Next comes the detention region, showing no glands. Finally, the midrib region has many digestive glands and several more trigger hairs.
When the water temperature drops below 17 degrees (C), the plant forms a hibernaculum and stays dormant during cold months. Aldrovanda is a tropical plant, but its ability to form a resting bud has allowed it to expand its distribution over temperate zones. A winter bud, measuring 10 mm or so, is formed at the apex at the end of summer in a temperate habitat. As the ice forms over the water surface, the bud sinks at the lake floor to protect itself and remains dormant. As the water warms in spring, the bud floats to the surface, and starts to expand. In tropical regions where water remains warm, the plant continues to grow throughout the year.
The tropical pitcher plants, Nepenthes, are climbing vines. Each leaf has a long tendril, at the tip of which develops a pitcher that retains some liquid to catch small animals. Generally, invertebrates are main prey for Nepenthes traps.
The pitchers come in astonishing varieties of shapes and colors. Some produce a pitcher of huge size capable of holding -x- liters of water. Occasionally, frogs and small lizards are reported to have been found in the liquid of such pitchers. There are some incidents of a bird captured in the pitcher in the wild. This makes Nepenthes the indisputable winner among all carnivorous plants for prey size category. These are events of serendipity, however, and the majority of prey consists of insects and other bugs.
Insects are attracted to the pitcher by combination of scents, color and nectar (Clarke). The prey falls into the pool of digestive liquid and drowns. As the insect's body decomposes, the digested materials are absorbed through the pitcher walls and used for growth and reproduction. The plants gain essential nutrients from the trapped animal that are deficient or lacking in the soils they grow in.
A recorded history of Nepenthes dates back to 1658 in French Madagascar. Colonial governor Etienne de Flacourt (appointed by the French East India Company) described a pitcher plant in Histoire de la Grande Isle de Madagascar under the local name "Amramitico". The species was later formally described as N. madagascariensis by J. L. M. Poiret in 1799. (Lloyd 1942, Kusakabe 1961, Kurata 1976).
In 1682, a Swedish physician, H. N. Grimm, in Ceylon (now Sri Lanka) reported a local pitcher plant from the island, which was later described as N. distillatoria by Carolus Linnaeus in 1753 (Kusakabe 1961, Kurata 1976).
Veitch & Sons (Kusakabe)...
The genus Nepenthes comprises some 94 species most occurring in the tropics of Southeast Asia. Sumatra, Malay Peninsular, Java and Borneo collectively support 52 endemic species (Clarke). The high degree of endemism in the region suggests the origin of the genus centers around Borneo (Juniper), with the island of Borneo alone containing 31 species, followed by Sumatra counting 29 species (Clarke). The secondary center of diversity includes the islands of New Guinea, Sulawesi and Mindanao as well as Peninsular Malaysia (Clarke)
The total distribution of the genus extends westward to the isolated population of N. khasiana in Assam (India), N. distillatoria in Sri Lanka, N. pervillei in the Seychelles, and to Madagascar with two species N. madagascariensis and N. masoalensis (Juniper et al). Eastward it reaches New Caledonia where N. vieillardii is found (Kurata).
The plants grow in nutrient-poor soils which are generally acidic and constantly wet. Nepenthes are not jungle plants (Kurata) and in general seem to have a low tolerance of shade (Juniper, et al). The plants climb among trees and shrubs or trail along the ground if there is no adjacent vegetation. (Clark). In Borneo, Nepenthes is found from sea level to 3500 m. Some inhabit in bogs, while some climb to a tall tree growing several meters (Clarke).
Nepenthes species can be divided into two groups for their habitat preference: 1) Lowlands (at altitudes less than 1000 meters) characterized by high temperature and humidity all day and 2) highlands (above 1000 meters) having a climate of cooler temperature at night and wetter in general, often covered with thick cloud, supporting moss growth (Kurata). Some highland species are epiphytes.
A Nepenthes plant produces two types of pitchers at different stages of its life. When young, the plant forms a rosette of leaves, with a relatively short stem. The pitchers produced in this stage are referred to as the "lower" or "terrestrial" pitcher. After a few years, as the plant grows more mature, the internode begins to elongate, and the plant enters the climbing stage. The pitchers change to what is referred to as the “upper” or “aerial” pitcher. Sometimes during this transition from a rosette to climbing form, a pitcher of an intermediate shape may appear.
The upper and lower pitchers within a given species can be so dramatically different in appearance that taxonomic confusion might arise, as it did in the past, with the same species being erroneously recorded as two different taxa. In cultivation, experience shows that cuttings obtained from a mature plant revert back to a juvenile stage in which the lower pitchers are produced.
Lower (or Terrestrial) Pitcher: The lower pitchers are produced in a younger plant forming a rosette. The pitcher typically looks globose in shape, and often rests on the ground. There are two parallel wings running vertically on the front of the pitcher exterior. This pair of often fringed wings serves as a ladder for crawling insects, leading the potential prey to the pitcher opening where nectar is served.
The pitcher bottom abruptly changes to a slender tendril that often grows from the frontal base of the pitcher. This often (but not always) orients the lower pitchers toward the rosette center.
Upper (or Aerial) Pitcher: The upper pitchers are usually slimmer, often funnel-like, with a wider opening at the top. The wings on the pitcher front are lacking or greatly reduced. The tendril is longer, and often forms a loop during its development in an attempt to clamp neighboring vegetation (like a tree branch). If successful, this helps alleviate the weight of the water-filled pitcher from the climbing stem, and at the same time, renders support to the plant in its ascent toward the tree canopy. The aerial pitcher usually contains much less liquid than the terrestrial counterpart.
The transition to the connecting tendril is more gradual in the upper pitcher. The pitcher bottom narrows as it turns toward the back of the pitcher and finally becomes a hanging tendril. The pitcher opening tends to face away from the stem.
In some species, a la N. ampullaria, the aerial pitcher production appears to have been abandoned altogether in a climbing plant, unless firm coiling is secured by the tendril. (See Clarke's picture of immature upper pitchers).
As a new leaf continues to develop, a slender tendril grows longer. The tendril has a tiny, hairy tip which gradually swells and, in a month or so, develops into a pitcher. The lid is tightly sealed until the pitcher has fully grown. An unopened pitcher already contains sterile liquid. When the lid opens, the trap is ready. The pitcher is filled with enough liquid to drown the victim.
In terms of leaf morphology, the appearance of a Nepenthes leaf presents some confusion. In Nepenthes, what appears to be a normal leaf blade is indeed the base of the leaf. The long tendril is an extended midrib, and the pitcher represents the true lamina (leaf blade). The leaf base has been greatly broadened to make up for the inadequate photosynthesis due to the color and form of the pitcher.
Lid: All pitchers have a flat structure called the lid that overhangs the pitcher opening. In many species, the lid prevents rainwater from diluting or overflowing the liquid inside, though in some, the size and almost vertical posture of the lid fail to offer any effective shield from rain. The main purpose of the lid appears to be attraction of prey. The lid contains scattered nectar glands (particularly) on the undersurface and serves to allure potential prey to the pitcher.
Some species have a small , bulged structure near the lid base on the undersurface of the lid. This is called the glandular crest. The specific purpose of it, besides having numerous nectar glands, is not known.
In most species, at the base of the lid grows a small , filiform structure called the spur. In terms of the pitcher leaf development, the spur represents the true apex (tip) of the Nepenthes leaf (Lloyd, Clarke). A true function of the spur, if any, is not known.
Peristome: The edge of the mouth of the pitcher is surrounded with a ridge of hardened tissues called the peristome. It consists of a series of ribs (quite similar in appearance to the mouth of a Cephalotus pitcher). On the inner side of the pitcher, each rib ends in a sharp, pointed tooth, aiming toward the pitcher bottom. The large nectar glands lie underneath the teeth along the inner pitcher mouth. Visiting insects are forced to lean over in a precarious position on the slippery peristome surface. In their attempt to lick the nectar hidden behind the teeth, many fall into the depths of the pitcher.
Pitcher Zoning: Right below the peristome extends the inner walls of slippery surface covered with fine wax fragments. As the insect tries to scale the wall, wax peals off, causing the insect to lose its foothold. This waxy coating continues half way down into the pitcher. (conductive and retentive zone) Further down in the lower portion of the pitcher, the walls are lined with numerous digestive glands. The pitcher liquid usually covers this area.
A microscopic image reveals... Slippery -gland - see microscope picture. (Kurata, Juniper et al)
Researchers have succeeded in isolating the enzymes secreted by Nepenthes using unopened pitchers. Some enzymes are found to act optimally in the high acidity level of pH 2-3. Glands secrete acids and digestive enzymes. The pitcher liquid shows the highest acidity in a recently opened pitcher, and the acidity level declines as the pitcher ages. This seems to suggest that the active digestion takes place in the pitcher using the plant's own enzymes, at least when the pitcher is young.
The pitcher liquid of Nepenthes is long known to be teemed with a multitude of commensal organisms, such as larvae of mosquitoes and flies, along with other micro-organisms. Forming a miniature ecosystem within the deadly pool of digestive juices, these organisms can thrive in the liquid and readily attack drowning insects as they fall into the pitcher. These commensals are likely to play a major role in the overall digestion sequence in the Nepenthes pitcher, particularly in the older pitchers.
The surface tension of the pitcher liquid is measured to be markedly lower than that of normal water. This promotes swift drowning of an insect by acting as the wetting agent to the otherwise water-resistant insect body.
The glands absorb the products of digestion. Unlike the indiscriminate absorption from the leaf surface as in Drosera and Pinguicula, Nepenthes pitcher selectively takes in particular amino-acid and other ions. This discriminatory absorption pattern is likened to what happens in the root system, suggesting the pitcher serves to simulate the function of a real root.
Observations also show that the pitcher normally maintains a constant liquid level. It means that the pitcher is capable of regulating the amount of water by absorbing excess water (after rains) and replenishing the lost water when necessary.
The flowers of Nepenthes are rather simple in structure. Many small flowers are borne on a long flower stalk. Inflorescences are either raceme or panicle. (See illustration on inflorescence types). Flowering generally occurs on mature plants that have entered the climbing stage bearing aerial pitchers.
The genus Nepenthes is
dioecious, with each individual
plant only producing either male
or female flowers. With the
exception of bromeliads, Nepenthes
is the only genus exhibiting
dioecism among carnivorous
Both male and female flowers
have four sepals and no petals.
In the male flower, a single
column supports crowded anthers
at the apex. The female flower
has an ellipsoid ovary divided
into four chambers, with four
It is noted that male
inflorescences generally bear
more flowers than females
(Clarke), often twice as many.
The glands on the sepal on both
male and female flowers produce
a copious amount of nectar that
accumulates on the concave sepal
Insects are considered the
main pollinators of Nepenthes
flowers. Based on limited field
reports, flies and moths appear
to be generalist pollinators
most often seen visiting
Nepenthes. They are,
however, only infrequently
observed. There is a speculation
that Nepenthes flowers
are in transition to
Wind-dispersal …. Germination –
dicot – seedling has a tiny
Drosophyllum is endemic
to the southwestern European Mediterranean coast. The plants grow along the Atlantic coast of Portugal, and
in small regions in
southern Spain and the northern tip of Morocco across the Straits of Gibraltar.
The plant is a woody shrub that can grow to a height of 1 m or more. Thick, branching, woody stems carry slender, narrow, tapering leaf (light green) filiform ? leaves lined with numerous stalked glands covered with sticky mucilage. Unlike sundews, neither the stalked glands nor the leaf exhibit any motion during prey trapping. The glandular leaf, reaching 25 cm long, has a deep furrow along its length
A leaf has a groove along
its length (M - length-wise groove) on the abaxial (lower) surface.
The leaf is produced twisted 180 degrees, resulting in a reverse circination of the rolled leaf as it emerges from the growth point. The length-wise furrow is formed on the abaxial (lower) surface of the leaf. The stalked glands grow on the adaxial (upper) surface as well as on both sides of the almost cylindrical leaf. Because of this arrangement, the stalked glands tend to face away from the plant center.
The leaves produce heavy aroma of honey.
Unlike most species of carnivorous plants that inhabit wet, acidic soil, Drosophyllum is an exception for its choice of habitat. It is typically found in dry, sandy gravel of alkaline soil. The Mediterranean climate creates wet winters and warm-to-cool, dry summers. The coastal early morning mist in summer provides necessary moisture to the plants. It is speculated that the mucilage over the stalked glands effectively absorbs the water vapor from the moist air, providing the plants with needed moisture.
The plant is believed to produce a chemical to inhibit the growth of other
plants nearby - a mechanism used by some
desert plants to avoid competition for the limited water resource.
The mucilage secretions in Drosophyllum does not seem to be significantly different from that of Drosera, except that it is more acidic, in the range of pH 2.5-3.0, compared to pH 5.0 for Drosera and pH 3.5-4.5 for Triphyophyllum (Juniper et al.). Drosophylum (like Pinguicula and Drosera) has sessile glands for digestion on their leaf surface in addition to the stalked mucilage glands. Sessile glands are dry until stimulated. In Drosophyllum, the stalked glands also secrete digestive fluids. The glands are brilliant red against the light green leaf surface.
Triphyophyllum grows in a rain forest, in a relatively dense shade. The soil in general is nutrient-deficient, and the habitat climate is described as six months of dry season (November to May) followed by peak rainfall in July-August. The well-rooted liana, by far, is the largest carnivorous plant known, reportedly growing up to 40 m in length. In its native habitat, the plant is observed to be growing in company of other carnivorous plants such as several species of Utricularia, Drosera indica and Genlisea africana. These species survive the dry season as seeds or in a dormant form (Juniper et al.).
The plant produces three different types of leaves, as reflected in its generic epithet. In its juvenile stage, the plant produces a rosette of conventional leaves from a short stem. The carnivorous glandular leaves develop only in the plant around 40-50 cm high. Further, the carnivorous leaves are produced only for several weeks just before the onset of the rainy season (May-August).
Once the plant reaches a height of 50 cm or more, the glandular leaves are no longer produced, and the plant enters the adult phase of its lifecycle. The internodes start to elongate and the third form of leaves emerge, which are oval and wavy and have two hooks at the extension of the midrib. The plant starts to grow rapidly, climbing high into the jungle canopy, using its hooked leaves to cling on to other vegetation. The adult liana is a great climber, somewhat resembling Nepenthes.
Interestingly, the cutting from the adult specimen is said to revert to the juvenile stage and the plant starts producing carnivorous glandular leaves again. The same rejuvenation phenomenon is seen in Nepenthes cuttings in cultivation in relation to their dimorphic (upper and lower) pitchers.
The carnivorous glandular leaf is almost cylindrical and the whole surface is
covered with stalked glands. The flat blade is reduced or absent, and the
carnivorous leaf, measuring 15-25 cm long, grows almost vertically from the
rosette center. The general appearance of the glandular leaf very much resembles that of
The stalked glands are of two sorts: short and long ones, being up to 3 mm long.
There also exist numerous sessile glands on the leaf surface.
The glandular leaf unfolds with a reverse circination, as in Drosophyllum. The
glandular leaves survive only for a few weeks before being shed.
The structure of the glands is almost identical to that of Drosera except the size (Juniper). As in Drosophyllum, the stalked glands do not show any movement during prey capture. Also, as in Drosophyllum, the sessile glands remain dry until stimulated. Stimulation of the stalked glands increases the mucilage secretions and at the same time initiates digestive secretions from the sessile glands. Both stalked and sessile glands have a strong red coloration that contrasts sharply against green leaf surface.
The plant flowers at the tree canopy
2006-11-23 Description Illustration Map Species Photography
The genus Cephalotus is monotypic containing Cephalotus follicularis. Commonly known as the Albany pitcher plant or Western Australian pitcher plant, this unusual-looking, hairy, compact plant with exquisitely constructed pitchers is a little darling of all carnivorous plants. First collected by Archibald Menzies during the Vancouver Expedition in 1791 (Lloyd), the natural distribution of the species is confined to narrow coastal stretches around Albany all the way westwards to Augusta in the extreme southwestern tip of Western Australia. The plant is ever-green and grows in dump, peaty soil, often in company of other carnivorous plants in the region such as sundews and bladderworts. The general climate of the habitat is described as cool, wet winters and warm, dry summers. Drizzles and nightly dews provide enough moisture to the plants during the dry summer months.
The plant produces two types of leaves, carnivorous pitcher leaves and conventional non-carnivorous foliage, both emerging from the short stem. An intermediate leaf form is sometimes observed. A mature plant forms a rosette of several centimeters in diameter. A pitcher is normally 5 cm or less in height and is attached to a long, cylindrical petiole. Some "giant" form is known that produces a pitcher almost twice as large. Roots are thick and branching with fibrous hairs. Underlying rhizomes often produce a new plant, forming a large cluster of plants in the wild.
NORMAL LEAF Conventional leaves are produced in spring. A green, flat, glossy leaf is oval-shaped, typically measuring 3 cm or so. The leaf is hairy around the rim as well as along the veins on the leaf. These conventional, photosynthetic leaves tend to stay close to the rosette center. They remain green and last for the whole year.
PITCHER LEAF As summer approaches, pitcher production begins, in tandem with the insect population growth. A slender petiole grows from the rosette center, that has a tiny, hairy blob at the tip, which gradually swells to become a pitcher. As the pitcher grows bigger, the petiole continues to elongate, often past the conventional leaves. The pitcher, now nearing the mature size, rests on the ground in a slightly slanted posture. In a day or so, the lid opens, and the trap is ready for prey acquisition. The pitcher already contains a small quantity of liquid at the base. Connected to the petiole at the neck, the pitcher always faces outward from the rosette center.
The pitcher exterior has a ridge lined with hairs and nectar glands on the frontal center. Two more ridges are provided, one on each side of the globose pitcher, slanted toward the frontal opening. These ridges serve as baited ladders for crawling insects leading to the pitcher orifice.
The mouth has a well-developed rim which is strongly ribbed. Each of the 20 or so ribs terminates in a sharp, downward-pointing tooth (jaw) toward the pitcher bottom. The nectar production is heaviest just beneath these teeth. This is where insects lean over for the final and fatal attempt to get a better lick.
Right below the sharp teeth along the rim forms the thick collar overhanging the pitcher bottom. This slightly narrows the pitcher opening. The surface of the collar is lined with short downward-pointing hairs (See Juniper photo), creating an impossible-to-climb vertical wall. The collar ends abruptly with a sharp edge pointing downward, creating additional barrier to escape from the pitcher cavity.
Cephalotus is known to possess two kinds of glands (small and large) presumably having different functions. Toward the pitcher bottom on each side of the inner surface is a kidney-shaped brown patch, where the larger digestive glands are found. The small er glands are scattered over much of the pitcher interior below the collar.
The circular lid overhangs the pitcher opening, preventing the rain water from diluting the liquid within. The lid normally rests at 45 degrees or so at the mouth. It is lined with white, translucent streaks toward the free edge. These fenestrations help to light up the otherwise somewhat dark pitcher interior, removing prey's hesitation to venture into the pitcher. The hairy lid has numerous nectar glands over its inner surface.
lid is immobile, at least for
the purpose of prey trapping, but it is often
observed that the front half of the lid bends down slowly to
prevent the loss of liquid inside when the air humidity decreases.
Ants are primary prey, as can be suspected from the pitcher lying on the ground, but some flying insects also fall victims to the nectar allure.
In their native Australia, Cephalotus flowers in summer (January-February). A flower stalk appears in the rosette center in early summer that grows to an unusually tall height of 2-3 feet. This makes the flower stand out among surrounding vegetation for pollinators. More importantly, the tall scape provides for a spatial separation of pollinator-prey zones.
Many small flowers are borne at the tip of a tall stalk. Each flower is only 4 mm across and white to pale green in color. The flower has no petals and 6-7 sepals give the flower its color. One flower produces only several seeds at most. Cephalotus is a hairy plant and the seeds are also covered with fine hairs. The plant is a slow grower and it takes many years for the seedling to reach a flowering age.
There are eight species of eastern North American pitcher plants all occurring in the Atlantic coastal regions of North America. Of these, seven species are confined to the southeastern part of the United States where they typically inhabit wet, sandy areas in the pineland, sometimes localized and rather isolated, but often with two or more species sharing the same habitat. This often results in various hybridization. One species extends its distribution all the way northward deep into a large part of eastern Canada.
The generic name Sarracenia was adopted in honor of Dr. M. S. Sarrazin of Quebec, an early discoverer. The common name for the genus came from their hollow, tubular leaves which are shaped and function like pitchers.
Pitcher plants are herbaceous (non-woody) perennials consisting of a rhizome with thick fibrous roots. The hollow trap leaves arise directly from the rhizome above the ground. The pitcher leaves form a rosette and are erect or nearly so in most species but are decumbent in some. The lid develops at the upper end of the pitcher. The lid is typically reflected over the pitcher opening, but can develop to form a domed hood in some species. The mature pitchers range in height from 10 to 100cm, or even more at times, depending on the species and growing conditions. See Description for more.
The cobra plant is a herbaceous perennial consisting of a rhizome, with fibrous roots. Tubular pitcher leaves arise
directly from the rhizome, forming a rosette. In this species, the hood of the pitcher
is well developed to form a dome, with the pitcher opening facing downward. The
pitcher lid is modified into a two-lobed, fishtail-like appendage projecting
downward from the front edge of the opening. A peculiar feature of the plant is
that the leaves twist about 180 degrees as they grow. As a
result, the pitcher openings tend to face outwardly from the plant center. This
conceivably provides wider coverage for prey acquisition. The
direction of the twist seems to be just about even between clockwise and
counter-clockwise in nature, though within a given individual the direction
Heliamphora was discovered by Sir R. Schomburgk on Roraima in 1838. The generic epithet translates to the "marsh pitcher"...
Most species have a short stem from which erect leaves arise, but some have a stem reaching 1 m or more.....
The plants use a flypaper trap to catch insects on their leaves, which are covered with stalked glands that secrete sticky glue. The plants look similar to some of the sundew species. This similarity, however, is more apparent than real. Unlike the mucilaginous secretions in Drosera, the glands on the Roridula leaf produce powerful resin. Water-based mucilage can be readily absorbed through the leaf surface, which is not the case for resinous glue. For this reason and the fact that the plants do not produce digestive enzymes, Lloyd and others had rejected the notion that Roridula plants were true carnivores. Recent studies have shown, however, that Roridula maintains a mutualistic relationship with assassin bugs (Rameridea) living on the plants. In fact, each species of Roridula has its own kind of assassin bug (Opel, 2005). The assassin bugs can freely move around on the sticky leaves without being caught. These carnivorous bugs live on the prey caught on the Roridula leaves. Indeed, these bugs are said to be found nowhere other than on Roridula plants. The excretion of the bugs deposited on the leaf is now absorbed by the glands on the leaf. The bugs serve as a surrogate to digest the prey for the plants. This arrangement, in principle, is no different from the case where the exogenous microorganisms like bacteria are used to perform the digestion of prey in many carnivorous plants some time during their digestion cycle.
The leaves have two kinds of glands. The stalked glands that secrete resinous glue are far simpler in structure compared with those in Drosera. The stalk is multi-cellular, but no vascular system is seen. The stalk shows no movement and the secretions appears to occur only once. The leaf surface contains simple sessile glands also, which are speculated to be responsible for absorption.
The plants produce a pink flower with 5 petals.
Butterworts are rosette of thin leaves, typically lying prostrate, with white, fibrous roots. The upper surface of the leaf is covered with short stalked glands that secrete clear sticky mucilage to trap small animal prey. The leaf feels greasy to the touch because of this secretions. This gave the plant its common name. The generic name Pinguicula is derived from the Latin word pinguis, meaning fat. See Description for more.
There are about 210 species of bladderworts worldwide, occurring practically every part of the globe. Some are terrestrial species found in moist-to-wet, often acid soils, and in sphagnum moss, while others are aquatic, preferring to be floating freely in quiet waters in ponds and ditches. Many terrestrial species in the tropics are epiphytic.
Some species exhibit intermediate life style, capable of adapting to either terrestrial or semi-aquatic habitats depending on the amount of rainfall of the season. Of all the bladderworts in the world, terrestrial species are, by far, the majority. Twenty species are found in the U.S. See Description for more.
The plants have light green thread-like leaves. The leaves radiate in all directions from the stem. The whole plant, including stems and flower stalks, is covered with fine, sticky hairs. The clear mucilage envelopes the tip of each hair to entrap small insect prey. In Byblis, the stalked mucilage glands remain green.
The climate of the habitat is characterized by wet winters and long, hot, dry summers. The plants' shoots die back during the dry period, being dormant in the form of rootstock, only to emerge again at the onset of winter rains.
Rainbow is a well-understood physical phenomenon created by optical properties of a sphere, as in air-borne vapors in the misty sky faraway. Thanks to the erect posture of the plants, the field densely populated with a massive number of rainbow plants, with their million dew drops, can effectively simulate a rainbow, with the refraction of sun's ray, causing differing wavelengths to form a spectrum of rainbow.
If you ever encounter such a situation in the field, just remember that the center of rainbow is always where your head casts its shadow - the anti-solar point.
The cross-section of a leaf is somewhat triangular...
Two type of glands are seen on the leaf surface, the stalked glands and sessile glands. The stalked glands (similar to those in Pinguicula, dissimilar to those in Drosera) have a unicellular stalk, with as many as 32 glandular cells at the tip of the stalk. The sessile glands, far more numerous than the stalked glands, have 8 glandular cells. The sessile glands secrete mucilage only when stimulated, and occur also on the adaxial surface where no stalked glands are seen. The main purpose of sessile glands appears absorption.
No enzymes have ever been detected from either of the glands.
The plant was initially described under Martynia lutea. Suggested as a possible carnivore by Beal in 1875, Mameli further established its carnivorous nature in 1916 (Juniper, et al). Lloyd somehow missed the papers, and did not include Ibicella in his book, The Carnivorous Plants (1942).
Of fifteen of so species of the family Martyniaceae, three species are suspected to be carnivorous: Ibicella lutea, Proboscidea parviflora and Proboscidea lousianica.
The plants grow natively in the arid soil in South America, but are now naturalized in southern California deserts. The upper surface of the leaves as well as the stems are covered with short hairs tipped with a sticky mucilage. These short hairs are only capable of trapping gnats and small dipterans, but often rather effectively. Studies have failed to detect any digestive enzyme production. The trapped prey is decomposed by the aids of external bacteria before the leaf can absorb its nutrients.
The plants grow to a height of 50 cm or more and assume a bushy appearance....
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