1CARNIVOROUS PLANTS特色:What is a carnivorous plant? To be considered canivorous, a plant must do the following: 1) attract prey, 2) trap prey, 3) digest prey,Carnivorous plants are found in various parts of the world.1. 生長地: Habitats range from dry, almost desert conditions to standing or slowly f lowing water. Altitudes extend from near sea level to about 9,000 feet2. What do they eat? Capable of capturing and digesting insects and other very small animals.3. Carnivorous plants do not pose any threat to man, but we are threatening their existence.4. it is well known that many of the carnivorous plants grow best in swamps or bogs where available nitrogen is scarce.Pitcher plants:1. Native to the bogs and swamps of Eastern North America,2. they have hollow, tubular leaves which form urn, or trumpet-shaped receptacles in which insects are captured.3. The colors plus the nectar the plant produces attract insects to an opening at the top with a very slippery lip.4. When insects crawl over the lip, they slide into the receptacle which contains water. It is difficult if not impossible for the insects to crawl out because the side walls of the pitcher are lined with stiff, sharp hairs, all pointing downwards.5. Ants form a large part of the pitcher plants prey although larger victims such as flies, wasps, crickets and even spiders are occasionally caught.
2Sundews (Drosera spp.)1. grow in North America2. Each leaf has an elliptical or almost circular blade supported by a slender leaf stalk.3. The blade is supplied with numerous hairs or tentacles, each of whichhas a large gland at its outer end. Each gland produces a droplet ofmucilage which has the appearance of a small dew drop. This can be seeneven in hot dry weather. When a small insect comes in contact with thetentacle, various glands produce enzymes, an acid, an antiseptic whichinhibits bacterial action, and more mucilage. Within a few seconds thetentacles begin to bend toward the animal and gradually press it firmlyinto the secreted mixture. After 24-48 hours, digestion of the softtissue is complete. The tentacles extend and the hard parts of the insectblow away or are washed off by rain. The leaf is then ready for anotherjuicy victim.Venus Flytrap (Dionaea muscipula)1. It grows on the coastal plain of North and South Carolina and is foundnowhere else in the world.3. The leaf stalk is broad and flat and carries out most of the plants photosynthesis. The leaf blade, on the other hand, acts as the trap.4. Every blade is hinged in the middle and each of the two halves bears glands for secreting nectar and 3 sensitive trigger hairs.5. If an insect happens to touch 2 of these hairs, the leaf halves fold together the animals are digested and absorbed by the plant.6. After a few days the leaf reopens and the insects exoskeleton is blown or washed away.Butterworts (Pinguicula spp.)1. Butterworts are found the Northern Hemisphere. They are found intemperate 氣候溫暖的 or cool temperate regions on wet soils.
32. These plants take the form of rosettes of yellow-green leaves3.The leaves lie close to the ground and have upturned edges. Numerousglands in the leaf blade 葉片 secrete a mucilage 黏液-like substance inwhich small insects become trapped5. This secretion, along with digestive enzymes and an antiseptic increase in amount as the insect struggles to free itself from the leaf. At about the same time, the margins of the leaf infold, producing a shallow cup in which the victim disintegrates 瓦解.6. The antiseptic properties of the butterworts secretions are so effective that many alpine peoples use the leaves to treat open wounds.Cobra Plant (Darlingtonia spp.)1. Growing in the wet meadows and marshes of western Oregon and northern California,2. the cobra plant (cobra lily) gets its common names from the fang-like 扇狀的 projections 突出 from the hood of its modified leaves that resemble the pitchers of pitcher plants.3. Insects are attracted to the slit-like opening on the side of the pitcher by bright colors and nectar. This carnivorous plant lures its insect prey with a sweet nectar which is inside the leaf opening under its hood.4. slippery smooth surface of the inner tube and the sharp, downward pointing hairs which effectively block any chance of escape.5. Furthermore, the insect is distracted by the light shining through thin, transparent places in the roof which resemble skylights. After repeated attempts to escape, the insect falls exhausted into the liquids of the receptacle where it is eventually digested through the activities of bacteria. Any attempts to scale the walls of the receptacle are repelled by extremely slippery places and by numerous down-curved hairs.
46. The prey found in these pitchers are usually ants, beetles, and flies with an occasional small frog or toad.Bladderworts (Utricularia spp.)1. Most bladderworts are aquatic but a few are terrestrial in moist locations.2. Small insects and other animals are trapped in the special bladder3. sensitive hairs are triggered by contact.4. Any very small animal that makes contact with the hairs is sucked into the trap .5. Once trapped inside the bladder, digestion soon takes place.