MIMOSA
PUDICA
1. BOTANICAL CLASSIFICATION: Plantae Magnoliophyta Magnoliopsida Rosidae Fabales Mimosaceae
KINGDOM: Plantae
DIVISION: Magnoliophyta
CLASS: Magnoliopsida
SUBCLASS: Rosidae
ORDER: Fabales
FAMILY: Mimosaceae
2. COMMON NAMES:
English: Sensitive Plant, Sleeping Grass
French: Sensitive
Latin : Mimosa Pudica Linn.
Other: Betguen Sosa (Guam); Memege (Niue); Mechiuaiu (Palau); Limemeihr (Pohnpei); Ra Kau Pikikaa (Cook Islands)
3. DESCRIPTION:
Native to Brazil, this short lived evergreen sub shrub is usually treated as an annual. It is grown for its curiosity value- the fern like leaves close up and droop when touched, usually re-opening within minutes. It has prickly stems and small, fluffy, ball shaped pink flowers in summer. It grows to a height of 5 ft and spreads around 3 ft- a perennial plant, it grows to a height of 0.5m with a spread of 0.3m. In some areas this plant is becoming a noxious weed. The stem is erect, slender and branching. The leaves are bipinnate, fern like and pale green- closing when disturbed. The flowers are pale lilac pink, occurring in globose heads and appearing in summer. Indigenous to the northern hemisphere, it is adaptable to most soils in an open, sunny position, and is drought and frost tender. Due to its ability to fix nitrogen from the air it does well on poor soils. "Sensitive Plant" folds up its leaves when touched or exposed to a flame. This plant requires a medium light exposure, an evenly moist soil, and temperatures between 60 and 85 degrees. One should use caution when handling seedlings because the plant dislikes root disturbance. Mimosa may be difficult to grow and is sensitive to over watering.
vstems- red-brown prickly.
vleaves- immediately fold by pulvini if touched, pinnae 4, often reddish, leaflets 12-25 pairs, acute, bristly, 9-12mm long, 1.5mm wide.
vflowers- pink, in globose heads, nearly 1cm in diameter, auxiliary, punduncle up to 2.5cm long.
vpods- crowded, flat, prickly, briskly.
vseeds- Bristles on seed pod cling to fur and clothing, about 2 mm broad, rounded, brown.
Venus Flytrap
The Venus Flytrap, Dionaea muscipula, is a carnivorous plant that catches and digests animal prey—mostly insects and arachnids. Its trapping structure is formed by the terminal portion of each of the plant's leaves and is triggered by tiny hairs on their inner surfaces. When an insect or spider crawling along the leaves comes into contact with one or more of the hairs twice in succession, the trap closes. The requirement of redundant triggering in this mechanism serves as a safeguard against the spurious expending of energy toward trapping other, non-living things which may not reward the plant with similar nutrition.
The plant's common name refers to Venus, the Roman goddess of love, whereas the genus name refers to Dione.[citation needed] Dionaea is a monotypic genus closely related to the waterwheel plant and sundews.
The Venus Flytrap is a small herb, forming a rosette of four to seven leaves, which arise from a short subterranean stem that is actually a bulb-like rhizome. Each leaf reaches a maximum size of about three to ten centimeters, depending on the time of year;[2] longer leaves with robust traps are usually formed after flowering. Flytraps that have more than 7 leaves are colonies formed by rosettes that have divided beneath the ground.
The leaf blade is divided into two regions: a flat, heart shaped photosynthetic capable petiole, and a pair of terminal lobes hinged at the midrib, forming the trap which is the true leaf. The upper surface of these lobes contains red anthocyanin pigments and its edges secrete mucilage. The lobes exhibit rapid plant movements, snapping shut when stimulated by prey. The trapping mechanism is tripped when prey items stumble against one of the three hair-like trichomes that are found on the upper surface of each of the lobes. The trapping mechanism is so specialized that it can distinguish between living prey and non-prey stimuli such as falling raindrops;[3] two trigger hairs must be touched in succession or one hair touched twice,[3] whereupon the lobes of the trap will snap shut in about 0.1 seconds.[4] The edges of the lobes are fringed by stiff hair-like protrusions or cilia, which mesh together and prevent large prey items from escaping. (These protrusions, and the trigger hairs, are probably homologous with the tentacles found in this plant’s close relatives, the sundews.) The holes in the meshwork allow small prey to escape, presumably because the benefit that would be obtained from them would be less than the cost of digesting them. If the prey is too small and escapes, the trap will reopen within 12 hours. If the prey moves around in the trap, it tightens and digestion begins more quickly.
Speed of closing can vary depending on the amount of humidity, light, size of prey, and general growing conditions. The speed with which traps close can be used as an indicator of a plant's general health. Venus Flytraps are not as humidity dependent as are some other carnivorous plants, such as Nepenthes, Cephalotus, most Heliamphora, and some Drosera.
The Venus Flytrap exhibits variations in petiole shape and length and whether the leaf lies flat on the ground or extends up at an angle of about 40-60 degrees. The four major forms are: 'typica', the most common, with broad decumbent petioles; 'erecta', with leaves at a 45 degree angle; 'linearis', with narrow petioles and leaves at 45 degrees; and 'filiformis', with extremely narrow or linear petioles. Except for 'filiformis', all of these can be stages in leaf production of any plant depending on season (decumbent in summer versus short versus semi-erect in spring), length of photoperiod (long petioles in spring versus short in summer), and intensity of light (wide petioles in low light intensity versus narrow in brighter light).[citation needed]
[edit] Mechanism of trapping
Closeup of one of the hinged trigger hairs.
Closed cilia around the prey
The Venus Flytrap is one of a very small group of plants that are capable of rapid movement, such as Mimosa, the Telegraph plant, sundews and bladderworts.
The mechanism by which the trap snaps shut involves a complex interaction between elasticity, turgor and growth. In the open, untripped state, the lobes are convex (bent outwards), but in the closed state, the lobes are concave (forming a cavity). It is the rapid flipping of this bistable state that closes the trap,[4] but the mechanism by which this occurs is still poorly understood. When the trigger hairs are stimulated, an action potential (mostly involving calcium ions — see calcium in biology) is generated, which propagates across the lobes and stimulates cells in the lobes and in the midrib between them.[5] Exactly what this stimulation does is still debated: cells in the outer layers of the lobes and midrib may rapidly secrete protons into their cell walls, loosening them and allowing them to swell rapidly by osmosis and acid growth; alternatively, cells in the inner layers of the lobes and midrib may rapidly secrete other ions, allowing water to follow by osmosis, and the cells to collapse. Both, either or neither of these mechanisms may play a role.[6]
If the prey is unable to escape, it will continue to stimulate the inner surface of the lobes, and this causes a further growth response that forces the edges of the lobes together, eventually sealing the trap hermetically and forming a 'stomach' in which digestion occurs. Digestion is catalysed by enzymes secreted by glands in the lobes. Digestion takes about ten days, after which the prey is reduced to a husk of chitin. The trap then reopens, and is ready for reuse, even though the trap rarely catches more than three insects in its lifetime.[citation needed]
[edit] Habitat
The Venus Flytrap is found in nitrogen-poor environments, such as bogs and wet savannahs. Small in stature and slow growing, the Venus flytrap tolerates fire well, and depends on periodic burning to suppress its competition.[7] Fire suppression threatens its future in the wild.[8] It survives in wet sandy and peaty soils. Although it has been successfully transplanted and grown in many locales around the world, it is found natively only in North and South Carolina in the United States, specifically within a 100 mile radius of Wilmington, North Carolina.[citation needed] One such place is North Carolina's Green Swamp. There also appears to be a naturalized species of Venus Flytraps in northern Florida as well as populations in the New Jersey Pine Barrens. According to anecdotal evidence[who?], a well-known horticulturist dropped thousands of seeds in Florida in hopes of spreading this plant. The nutritional poverty of the soil is the reason that the plant relies on such elaborate traps: insect prey provide the nitrogen for protein formation that the soil cannot. The Venus Flytrap is not a tropical plant and can tolerate mild winters. In fact, Venus Flytraps that do not go through a period of winter dormancy will weaken and die after a period of time.[citation needed]
[edit] Cultivation
Venus Flytraps are popular as cultivated plants, but have a reputation for being difficult to grow. These plants are swamp plants, and as such, most home growers are unable to replicate the plant's natural habitat. Successfully growing these specialized plants requires recreating a close approximation to the plant's natural habitat.
Time-lapse photography of a growing trap.
Venus flytraps can be grown outside on a deck, window sill, or in the garden that receives two to four hours of sunlight.[9] In areas of lower humidity, the plant can survive with frequent watering and a drainage system to prevent fungal growth. It is also beneficial to keep it in a tray with about an inch of water to maintain higher humidity levels. Stagnant water is dangerous for the plant, so using pebbles to elevate the plant from the water is safer for the plant. Venus flytraps grow better still in a greenhouse which often leads to healthy, vigorous and colourful plants. The colour of the trap leaves may be used as an indicator of sufficient light; in appropriate conditions the inside of each trap should be bright red in colour for most varieties. Insufficient light leads to the inside of the trap turning light green, although studies have shown other factors can contribute to the lack of red pigmentation. Low light also causes etiolation and makes plants more susceptible to diseases.
Venus flytraps are best grown in mixtures of sphagnum peat moss and/or peat often with the addition of sand, perlite or other inert salt free material. Soil pH should be in the range of 3.9 to 4.8.
The 'Dentate' cultivar of the venus fly trap in cultivation
Venus Flytraps ideally should not be watered with tap water as accumulated salts in tap water may kill carnivorous plants. While soft water with TDS of 100 ppm or less yields good growth, both distilled, reverse osmosis water or clean rain water are ideal. The soil should be kept constantly moist by placing the pot in a tray full of water, with the root bulb of the plant allowed to be above the level of the water at least part of the time to prevent root rot in stagnant water. There is no danger of over-watering as Venus flytraps can survive short periods of immersion underwater.[9]
Some horticulturists have experimented with giving small amounts of fertiliser to Venus flytraps, usually applying diluted solutions of products formulated for epiphytes, using cotton swabs, to the plant's foliage. Another method of fertiliser application is a spray bottle or pump. Beginners, however, and those without expendable plants, would be wise to avoid fertiliser in favor of insects.
Healthy venus flytraps produce flowers in the spring
Venus flytraps are entirely capable of catching their own food; thus, feeding them manually is not necessary. If for some reason a grower wishes to feed a flytrap, live insects no larger than 1/3 of the size of the trap may be used, as larger insects tend to have a detrimental effect on the plant as they often drastically shorten the individual trap's life and/or cause it to die. Algal growth near the plant is an indicator of overfeeding, as is an abundance of dead, black traps.
Healthy Venus flytraps will produce scapes of white flowers in spring, however, many growers remove the flowering stem early (2~3 inches), as flowering consumes some of the plant's energy, and reduces the rate of trap production. If healthy plants are allowed to flower, successful pollination will result in the production of dozens of small, shiny black seeds, which can be sown immediately or stored in the refrigerator.
Venus flytraps have a necessary winter dormancy period, triggered by nighttime temperatures below 10 °C (50 °F) and reduced day length.[9] In climates with mild winters they can be kept outside to overwinter (hardiness zone 9 or greater). The soil should be kept slightly moist and the area well ventilated to prevent the growth of grey mold. Those who live in areas with extremely cold winters (hardiness zone 8 or less) might consider placing plants in a plastic bag in the refrigerator for two to three months, starting in Autumn, although they can survive freeze-over for brief periods of time.[9]
Plants can be propagated by seed, although seedlings will take several years to mature. More commonly, they may be propagated by division in spring or summer.
[edit] Cultivars
Typical variety of the Venus Flytrap.
Dionaea muscipula 'Akai Ryu', Japanese for 'Red Dragon', in cultivation.
Venus Flytraps are, by far, the most commonly recognized and cultivated carnivorous plant. They are sold as houseplants and are often found at florists, hardware stores and supermarkets. Although the genus is monotypic, during the past ten years or so, large quantities of cultivars have come into the market through tissue culture of select genetic mutations. It is through tissue culture that great quantities of plants are raised for commercial markets.
Some of the registered cultivars (cultivated varieties) include (name of originator in brackets):
- Dionaea muscipula 'Akai Ryu' {R.Gagliardo}
- Dionaea muscipula 'Big Mouth' {T.Camilleri}
- Dionaea muscipula 'Bohemian Garnet' {M.Srba}
- Dionaea muscipula 'Clayton's Red Sunset' {C.Clayton}
- Dionaea muscipula 'Clumping Cultivar' {D'Amato}
- Dionaea muscipula 'Dentate' {D'Amato}
- Dionaea muscipula 'Dentate Traps' {B.Meyers-Rice}
- Dionaea muscipula 'Dente' {D'Amato}
- Dionaea muscipula 'Fused Tooth' {D'Amato}
- Dionaea muscipula 'Jaws' {L.Song}
- Dionaea muscipula 'Kinchyaku' {K.Kondo}
- Dionaea muscipula 'Red Piranha' {E.Read}
- Dionaea muscipula 'Red Rosetted' {D'Amato}
- Dionaea muscipula 'Royal Red' {AUPBR 464}
- Dionaea muscipula 'Sawtooth' {B.Meyers-Rice}
An unofficial list includes many more names, with more added annually. None of these "variation names" are officially recognized unless the name is properly documented, registered and accepted by the International Registration Authority for carnivorous plant cultivars, the International Carnivorous Plant Society.
