Invasive Species/Invasive Species List
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This is the National Invasive Species Official List with information on each taxon. As indicated here, one should study the following:
- Common name and scientific name
- Pictures of the species with unique identification tips, damage it causes, and life cycle
- Region of origin and year of introduction
- State or body of water where first discovered
- How was it introduced
- Transport – how is it spread and history of its spread throughout the country
- Distribution maps
- Mode of reproduction
- Adaptive anatomy and special adaptions to the environment
- Habitat characteristics as diet, behavior, niche, species displacement, trophic level
- Damage it does and how it effects the environment and natural food web of the environment-ecological, biological, human health and economic damage
- Preventive measures
- Control methods and effectiveness of each methods
- Laws or regulations about collecting or distributing this species
Invertebrates
For more information, see Invasive Species List/Invertebrates.
Asian Citrus Psyllid | Asian Longhorned Beetle | Asian Tiger Mosquito | Brown Marmorated Stink Bug | Cactus Moth | Chilli Thrips | |
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Appearance | Aphid-like; grayish-tan; brown markings; mottled brown wings | White spots on back; shiny black color; antennae are as long/longer than body, segments alternate between white and black; feet are bluish | Black and silvery scales; white stripe down back | Shield shaped; mottled brown-gray; 4th antennal segment has white band | Grayish-brown; | Pale colored; about 2 mm long; |
Native Range | Tropical and subtropical southwestern Asia | Eastern China, Japan, Korea, and the Isle of Hainan | Asia | East Asia (China, Korea, Japan) | South America | Southern Asia |
Introduction | Palm Beach County, Florida, June, 1998; probably on imported plants | Brooklyn, NY, Aug. 1996; believed to have infested wood packing material | Late 1800s (Hawaii); 1985 (Continental U.S.); in tires imported from Asia | First confirmed 2001, Allentown, PA, specimens collected early as 1996; possibly in shipping material | 1989; imported to the Caribbean to control prickly pear cacti; arrived in U.S. naturally or in cargo imported from the Caribbean | First discovered in HI, 1987; first established pop. discovered in FL, 2005; possibly infested commodity shipments |
Life Cycle | Females lay 800+ eggs; 5 nymphal instars; about 10 gen. per year; no diapause | 1 gen/year; adults most active late jun.-early Jul.; lay ~32 eggs; larvae feed on cambial layer; pupation in heartwood; may overwinter as larva/pupa; adults emerge in May | In eggs for at most 1 year, larvae stage 5-10 days, pupal stage 2 days. Larvae develop into pupation after 4 instars. | Eggs laid Jun.-Aug on underside of leaves; mating in spring after diapause; egg masses are ~25 eggs; 5 nymphal instars; females lay up to 400 eggs | Eggs laid on cactus plants in a stacked position; larvae burrow into cactus close to eggs. Life cycle is about 90 days. | Two instars, pre-pupal and pupal. Becomes an adult in ~2 weeks. Females lay an average 40 eggs in lifetime. |
Impact | Cause plant tips to die back or become contorted; vector genus Candidatus Liberibacter which causes HLB | Cause damage to many species of hardwood; repeated infestations may cause tree death | Has aggressive daytime human biting behavior and ability to vector many viruses, including West Nile virus | Feeds on a variety of plants (fruit trees, ornamentals, some crops); feeding on fruits may lead to "cat facing", rendering it unsalable as fresh produce; household pest | Feeds on prickly pear cacti, which are important as ornamentals in the U.S. and are a staple crop in Mexico | Attacks over 100 crops, resulting in defoliation and crop loss |
Control | Remove infested trees; biocontrol may be used in IPM, but is ineffective alone; insecticides may be used; intercropping | Chip & burn infested trees, grind stump; apply insecticides to trees near infestation | Removal of eggs, eliminating standing water | Manual/mechanical removal from home; pesticides may be used for agricultural infestations; biological control being investigated | Bacteria Bacillus thuringiensis can kill larvae; some wasps eat the larvae; ants can protect the cacti from the moths. | Insecticides spinosyn and abamectin work. |
Citrus Longhorned Beetle | Common Pine Shoot Beetle | Emerald Ash Borer | European Gypsy Moth | European Spruce Bark Beetle | Formosan Subterranean Termite | |
Appearance | Black with white spots, females larger than males, males have longer antennae, white-blue markings on pronotum | Adults cylindrical, 3-5mm long, head & thorax shiny black, elytra reddish-brown to black | Adults green/brassy with green elytra, 8.5-13mm long, females larger than males; larvae flattened, cream-color, with 10 segments | Males are grayish brown, can fly; females are larger, white with black bands, cannot fly; | Cylindrical; dark brown; yellowish hairs; 4 spines on each side of elytral declivity | Alates: yellow-brown; numerous small hairs on wings; attracted to light. Soldiers: Orange-brown; oval head; curved mandibles; whitish body |
Native Range | China, Japan, and Korea | Eurasia and northern Africa | Eastern Russia, Northern China, Japan, and Korea | Europe | Europe and Asia | China |
Introduction | Tukwila, Washington 2001 (eradicated); infested nursery stock | Near Cleveland, OH July, 1992; infested imported wood packing material | 2002, Canton, MI; accidentally in cargo imported from Asia | Massachusetts, 1869; imported intentionally for silk production, accidentally released | Intercepted in packing crates and unprocessed wood items at ports | 1960s; arrived accidentally on ships from the Pacific |
Life Cycle | Adults abundant May-Jul.; eggs laid under bark, avg of 15/fem., up to 200, hatch after 1-3 w.; pupation lasts 4-6 w.; pre-adult matures in 1-2 w.; takes ~1 year to develop | Fem. make vertical egg galleries in inner bark/outer sapwood, 4-10in. long; hatched larvae make feeding galleries 1.5-3.5in. long; new adults leave bark, leaving 2mm exit holes | 1-2 years/generation; fem. usually lay 40-70 eggs, may be >200; eggs laid between bark layers or crevices, hatch after 2 weeks; 4 larval instars; D-shaped exit holes | Fem. lay masses of 500-1200 eggs in Jul., hatch late Apr.-early May; males have 5 instars, 6 for fem.; larvae feed for ~2 months; pupation lasts 1-2 w.; adults die after 1-2 w. | Larvae feed in phloem, pupate, emerge as adults; 1-2 gen/year; overwinter as adults in litter or under bark | |
Impact | Attacks numerous species of hardwood trees; has the ability to attack live trees; primary damage is that of larval maturation feeding | Capable of damaging and killing pine trees by feeding on young shoots | Maturation feeding in inner phloem, cambium, and outer xylem is the primary damage; also lightly defoliates trees feeding on foliage after adults emerge | Defoliates trees; larvae may consume up to one square foot of foliage per day | Has potential to damage forests in North America; transmit blue-stain fungi on sapwood, disrupting flow of lethal resin into galleries | Competes with native species; causes structural damage to buildings |
Control | Mechanical exclusion; injection of surrounding trees with systemic insecticides; biologically with the fungi Beauveria brongniartii | Trap logs; cover sprays applied early to mid-June | Chemical control includes mamectin benzoate, imidicloprid, and dinotefuran | Trapping; manual destruction of eggs; chemically w/ pheromones and pesticides; biological w/ white-footed mouse, forest caterpillar hunter, fungal pathogens, viruses | ||
Giant African Snail | Glassy-Winged Sharpshooter | Hemlock Woolly Adelgid | Light Brown Apple Moth | Mediterranean Fruit Fly | Mexican Fruit Fly | |
Appearance | Adult height is ~7cm (2.8in), 20cm (7.9in) or longer. Shell has a cone shape, twice as high as it is broad. Both clockwise and counter-clockwise directions are possible. Brown is the most common color, and shell is banded. | 12 mm in length, dark brown-black undersides, yellow eyes, head/back are speckled. Transparent wings. | Winged and wingless adults; females are oval, blackish-gray, and about 1mm in length. Nymphs around same size, reddish-brown. White/waxy tufts cover their bodies throughout life | |||
Native Range | East Africa | Northeastern Mexico | Southern Japan, India, SW china, and Taiwan | |||
Introduction | Pet trade, food. | California, with ornamental/agricultural stock. | First described in western North America in 1924; first reported in eastern US in 1951 near Richmond, VA, accidentally transferred from Asia | |||
Life Cycle | Adult size reached in ~six months, life expectancy is usually ~10 years in the wild (5-6 not in the wild). They are active at night. Eggs/clutch is around 200, hatching viability ~90%. | Females lay in 10-12 masses in late March-April. Nymphs hatch in 10-14 days, go through 5 immature stages, 1st generation adults come out in May-July. 2nd generation comes out June-October. | ||||
Impact | Feeds on plant fluids, makes the leaves look dry and whitewashed. | |||||
Control | Keep the insect out of new areas. Small wasps attack sharpshooter eggs. Use imidacloprid to slow the spread of disease on Xylella-susceptible plants. | |||||
Pink Bollworm | Pink Hibiscus Mealybug | Red Imported Fire Ant | Russian Wheat Aphid | Silverleaf Whitefly | Soybean Cyst Nematode | |
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Aquatic Animals
For more information, see Invasive Species List/Aquatic Animals.
Alewife | Asian Clam | Asian Shore Crab | Asian Swamp Eel | Chinese Mitten Crab | Clubbed Tunicate | |
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Appearance | Small with a dark dorsal side, bluish to greenish, and light sides with horizontal darker stripes. Black spot located behind the eye. Scales that line up in a row along the belly. Adult is about 15-18 cm in length in the freshwater variety, marine alewives can reach up to 30 cm. | Less than 50 mm, outside of the shell is normally yellow-green with concentric rings, color can flake, leaving white spots, lightly purple on the inside. Typical oval-triangular shape, with a dorsal “beak” or umbo at the peak of the shell. | Square-shaped shell with 3 spines on each side of the carapace. Carapace color ranges from green to purple to orange-brown to red. Light and dark bands along its legs and red spots on its claws. | Claws equal size with white tips and hair. Carapace (shell) up to 4 inches wide, light brown to olive color. Eight sharp pointed walking legs; no swimming legs, twice as long as the carapace is wide | ||
Native Range | Possibly Lake Ontario, the Atlantic coast and its tributaries | Freshwaters of eastern and southern Asia (also occurs naturally in Africa) | Western Pacific Ocean from Russia, along the Korean and Chinese coasts to Hong Kong, and the Japanese archipelago | Pacific coast of China and Korea, East Asia | ||
Introduction | Spread to Lake Erie through the Welland Canal; presumed to have spread from Lake Erie to other Great Lakes via the Detroit River and Lake St. Clair, intentionally stocked in inland waters. | First detected in US waters in 1938 in the Columbia River, Washington. Assumed to have been imported as a food source for the immigrating Chinese population. May have come in with the importation of the Giant Pacific oyster also from the Asia. | First discovered: 1988, Cape May County, New Jersey, most likely introduced through ballast water | Introduced to US in: 1991 (West Coast); 2005 (East Coast), through ship ballast water and live release | ||
Life Cycle | Spawns once a year from late April to early June. In less than a week, the young alewives hatch and begin feeding primarily on zooplankton. In the fall, the young alewives make their way back to the sea or into the deep waters of freshwater lakes or rivers. | Adults can live 3‐4 years, and typically reproduce two times a year. Egg fertilization is internal and the larval clams are brooded on the gill where they transform into juveniles in about 4-5 days. | Larvae: Planktonic for approximately 1-2 months, developing in marine waters. Maturity: After spending 1-4 years in fresh or brackish water, males and females migrate downstream and reach sexual maturity in brackish waters of the estuary. | |||
Impact | Dense population can lead to reduced native fish populations due to competition. Eating them has been found to cause reproductive failure in landlocked salmon and trout species. Causes an illness called Cayuga Syndrome, which can causes 100% mortality in landlocked salmon and trout. | Filters out phytoplankton and other particles suspended in the water that are also important food sources. Large numbers, either dead or alive, clog water intake pipes used in power and water industries. | It could also out-compete native mud crabs, blue crabs and lobsters. Voracious appetite and has been known to feed on commercially important species, such as larval lobsters. | Aggressive and may compete with native blue crab and local species. Burrowing habits threaten stream bank and earthen dam stability, promote erosion and habitat loss. | ||
Control | Increasing the predator base has been the most effective. Trout and salmon stockings have been successful in reducing the alewife population | Benthic barriers have been demonstrated to be effective for short-term control, but non-target mortality may be high. Chemical molluscicides are available, but are not species-specific, may harm native species to a greater extent. | Parasites help control in native range only. Tracking the shore crab's spread along the coastline. Ballast water management. | Generally illegal to import, transport, or possess live Chinese mitten crabs in the US. New source of crab for the Chinese market, import unwanted crabs from Europe to replenish local purebred stock, China introduced vending machines to sell the crab in the subways. | ||
Eurasian Ruffe | European Green Crab | Lionfish | Northern Snakehead | New Zealand Mud Snail | Nutria | |
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Quagga Mussel | Round Goby | Rusty Crayfish | Sea Lamprey | Sea Squirt | Spiny Water Flea | |
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Veined Rapa Whelk | White Spotted Jellyfish | Zebra Mussel | ||||
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The list also includes Asian carps, but no specific species are listed. Some of the most significant species of Asian carps in the United States are silver carp, bighead carp, grass carp, and black carp.
Silver Carp | Bighead Carp | Grass Carp | Black Carp | |
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Terrestrial Plants
For more information, see Invasive Species List/Terrestrial Plants.
Air Potato | Autumn Olive | Beach Vitex | Brazilian Peppertree | Canada Thistle | Chinese Tallow | |
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Cogongrass | Common Buckthorn | Common Teasel | Dalmatian Toadflax | Diffuse Knapweed | Downy Brome | |
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Fig Buttercup | Garlic Mustard | Giant Hogweed | Hairy Whitetop | Houndstongue | Japanese Climbing Fern | |
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Japanese Honeysuckle | Japanese Knotweed | Japanese Spiraea | Japanese Stilt Grass | Johnsongrass | Kudzu | |
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Leafy Spurge | Medusahead | Mile-A-Minute Weed | Multiflora Rose | Musk Thistle | Old World Climbing Fern | |
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Princess Tree | Purple Star Thistle | Russian Knapweed | Russian Olive | Saltcedar | St. Johnswort | |
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Scotch Broom | Scotch Thistle | Spotted Knapweed | Tree-of-Heaven | Tropical Soda Apple | Whitetop | |
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Witchweed | Yellow Star Thistle | Yellow Toadflax | ||||
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Aquatic Plants
For more information, see Invasive Species List/Aquatic Plants.
Alligatorweed | Brazilian Waterweed | Caulerpa, Mediterranean Clone | Common Reed | Curly Pondweed | Rock Snot | |
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Eurasian Watermilfoil | Giant Reed | Giant Salvinia | Hydrilla | Melaleuca | Purple Loosestrife | |
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Water Hyacinth | Water Lettuce | Water Spinach | ||||
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Fungi
Viruses
Additional Information on Taxa
Although it is not necessary to know information on the broader taxa (i.e., taxonomic classifications above species), it may be helpful.
Additional Information on Taxa
Class InsectaAlthough this taxon is not specifically mentioned on the official list, it is a good idea to know that in order to be classified as an Insect, an organism must possess the following characteristics:
For an explanation of these terms, please visit this site [1]
Order Diptera: True FliesDiptera is an order of insects with the following general characteristics:
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Glossary
Glossary
Term | Definition |
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Achene | A small, usually single-seeded, dry, indehiscent (does not open at maturity) fruit |
Adipose fin | A soft, fleshy fin found on the back behind the dorsal fin and just forward of the caudal fin. It is absent in many fish families, but is found in Salmonidae, characins and catfishes. |
Adventitious bud | A bud that is not terminal or axillary, occurring elsewhere on the plant |
Adventitious roots | Originate from the stem, branches, leaves, or old woody roots rather than a primary root |
Allelopathy | The chemical inhibition of one organism by another, influencing the germination, growth, survival, and/or reproduction of the affected species |
Anadromous | Fish that migrate from the sea up into fresh water to spawn |
Anal fin | The anal/cloacal fin is located on the ventral surface behind the anus/cloaca. It is used to stabilize the fish while swimming. |
Annual | A plant that lives, reproduces, and dies in one growing season |
Anthropochory | Dispersal of seeds of a plant by means of human activity |
Apomixis | Seed production without fertilization, in which meiosis and fusion of gametes are partially or totally suppressed |
Aril | A specialized outgrowth from a seed that partly or completely covers the seed |
Auricle | A small lobe or projection, growing from the base of a leaf blade or sheath |
Axil | The angle between the upper side of the stem and a leaf, branch, or petiole |
Axillary bud | An embryonic shoot located in the axil of a leaf. Each bud has the potential to form shoots, and may be specialized in producing either vegetative shoots (stems and branches) or reproductive shoots (flowers). |
Berry | A fleshy fruit with several seeds, derived from a single ovary |
Biennial | Plants that need two growing seasons to complete their life cycle, normally vegetative growth the first year and flowering the second year |
Bract | A specialized leaf-like structure, from which a flower or flower stalk grows; some may be very small |
Bud | An undeveloped or embryonic shoot and normally occurs in the axil of a leaf or at the tip of a stem |
Budding | A form of asexual reproduction in which a new organism develops from an outgrowth or bud due to cell division at one particular site. The new organism remains attached as it grows, separating from the parent organism only when it is mature. |
Bulbil | A small bulb-like structure, generally formed in a leaf axil, that detaches from the parent plant and functions in vegetative reproduction |
Calyx | The collective group of sepals of a flower |
Capsule | A dry, splitting fruit that grows from more than one carpel, usually with several or many seeds |
Carpel | The basic female unit of a flower that bears the ovules; several may be united to form a compound pistil |
Catkin | A dense spike of many flowers with no petals |
Caudal fin | The tail fin, located at the end of the caudal peduncle and is used for propulsion. May be heterocercal, protocercal, homocercal, or diphycercal. |
Clonal colony | A group of genetically identical individuals, such as plants, fungi, or bacteria, that have grown in a given location, all originating vegetatively, not sexually, from a single ancestor |
Clonal fragmentation | See Fragmentation |
Complete metamorphosis | See Holometabolism |
Corolla | All of the petals on a flower |
Cotyledon | An embryonic seed leaf; there is characteristically 1 for monocots and 2 for dicots |
Creeping rootstalk | See Rhizome |
Crown | The place where the roots and stem meet, which may or may not be clearly visible |
Cuticle | A term used for any of a variety of tough but flexible, non-mineral outer coverings of an organism, or parts of an organism, that provide protection |
Diapause | The delay in development in response to regularly and recurring periods of adverse environmental conditions |
Dorsal fins | Located on the back. The dorsal fins serve to protect the fish against rolling, and assist it in sudden turns and stops. |
Drupe | A fleshy fruit with a firm structure derived from the lining of the ovary wall that encloses the seed such as a peach or almond |
Ecdysis | The molting of the cuticle in many invertebrates |
Emergent | Referring to an aquatic plant that extends above the water’s surface |
Euryhaline | The ability to tolerate a wide range of salinities |
Eurytopic | Able to tolerate a wide range of habitats or ecological conditions |
Exfoliating | Referring to bark, peeling off in layers |
Exoskeleton | The external skeleton that supports and protects an animal's body |
Fenestration | A term in botany that refers to natural holes in the leaves of some species of plants |
Follicle | A fruit derived from a single carpel that splits along one suture |
Fouling | An accumulation of organisms that attaches to naturally occurring and manmade submerged hard surfaces such as rocks, shells, ships, intake pipes, and other submerged equipment or machinery |
Fragmentation | A form of asexual reproduction or cloning in which an organism is split into fragments. Each of these fragments develop into mature, fully grown individuals that are clones of the original organism. |
Fruit | The seed-bearing structure in angiosperms formed from the ovary after flowering |
Genet | See Clonal colony |
Geophyte | A plant which possesses an underground storage organ which enable plants to survive adverse conditions (such as cold, excessive heat, lack of light, or drought) |
Heartwood | The harder, non-living inner layers in the stem of a woody plant |
Hemimetabolism | The mode of development of certain insects that includes three distinct stages: the egg, nymph, and the adult stage. They go through gradual changes; there is no pupal stage. The nymph often somewhat resembles the adult stage but lacks wings and functional reproductive organs. |
Herbaceous plant | A plant in which all structures above the surface of the soil, vegetative or reproductive, die back at the end of the annual growing season, and never become woody. While these structures are annual in nature, the plant itself may be annual, biannual, or perennial. |
Hermaphrodite | An organism that has reproductive organs normally associated with both male and female sexes |
Heterocercal | A type of caudal fin in which the vertebrae extend into the upper lobe of the tail, making it longer (as in sharks). May be “reversed heterocercal,” in which the vertebrae extend into the lower lobe of the fin instead. |
Holometabolism | A form of insect development which includes four life stages – an embryo or egg, a larva, a pupa, and an imago or adult |
Homocercal | A type of caudal fin in which the fin appears superficially symmetric but in fact the vertebrae extend for a very short distance into the upper lobe of the fin. May be rounded, truncated, forked, emarginate, or lunate. |
Imago | The last stage an insect attains during its metamorphosis, its process of growth and development, during which it attains maturity. |
Incomplete metamorphosis | See Hemimetabolism |
Instar | A developmental stage of arthropods (e.g., insects) between each molt (ecdysis), until sexual maturity is reached |
Internode | A portion of a stem between two nodes |
Involucre | A structure that surrounds the base of another structure, often applied to a set of bracts below the inflorescence |
Larva | A distinct juvenile form many animals undergo before metamorphosis into adults |
Leaflet | A separate blade among others comprising a compound leaf |
Legume | A pod-like fruit that grows from a single carpel and splits along two sides as occurs in the bean family, for example |
Lenticel | A small, corky pore or narrow line on the surface of the stems of woody plants that allows the interchange of gases between the interior tissue and the surrounding air |
Ligule | An appendage at the top of a leaf sheaf |
Metamorphosis | A biological process by which an animal physically develops after birth or hatching, involving a conspicuous and relatively abrupt change in the animal's body structure through cell growth and differentiation |
Monocarpic | Plants that live for a number of years until flowering and seed set, after which they die |
Monoculture | An instance of a single type of plant growing over a large area |
Node | A portion of the stem that holds one or more leaves, as well as buds which can grow into branches (with leaves, conifer cones, or inflorescences) and produce adventitious roots |
Noxious Weed | A weed that has been designated by an agricultural authority as one that is injurious to agricultural or horticultural crops, natural habitats or ecosystems, or humans or livestock |
Nymph | The immature form of some invertebrates, particularly insects, which undergoes gradual metamorphosis before reaching its adult stage. Unlike a typical larva, a nymph's overall form already resembles that of the adult. In addition, while a nymph molts it never enters a pupal stage, and instead goes through several stages in between molts called instars. |
Ocrea | Membranous sheath around the stem just above the base of a leaf; often found in members of Polygonaceae (e.g. Japanese knotweed) |
Ovoviviparity | A mode of reproduction in animals in which embryos that develop inside eggs remain in the mother's body until they are ready to hatch. This method of reproduction is similar to viviparity, but the embryos have no placental connection with the mother and receive their nourishment from a yolk sac. |
Panicle | A branching inflorescence or flower cluster that is broad at the base and tapers towards the top |
Pappus | The modified calyx of the Asteraceae, consisting of awns, scales, or bristles at the apex of the achene |
Parasitoid | An organism that spends a significant portion of its life history attached to or within a single host organism in a relationship that is in essence parasitic. Unlike a true parasite, however, it ultimately sterilizes or kills, and sometimes consumes, the host. |
Parthenogenesis | A natural form of asexual reproduction in which growth and development of embryos occur without fertilization |
Pectoral fins | Paired fins located on each side, usually just behind the operculum, and are homologous to the forelimbs of tetrapods |
Pedicel | The stalk of a single flower within an inflorescence |
Pelvic fins | Typically located ventrally below and behind the pectoral fins, although in many fish families they may be positioned in front of the pectoral fins (e.g. cods). They are homologous to the hindlimbs of tetrapods. The pelvic fin assists the fish in going up or down through the water, turning sharply, and stopping quickly. |
Perennial | A plant that lives for more than two years, either herbaceous or woody |
Petal | One of the inner set of floral leaves; often white or colored to attract pollinators |
Petiole | A leaf stalk supporting a blade and attaching to a stem at a node |
Pistil | The female organ of the flower, composed of an ovary, style, and stigma |
Pith | The central tissue in a stem or root, surrounded by vascular tissue |
Polygynandry | The sexual reproductive strategy in which two or more males have an exclusive sexual relationship with two or more females. The advantage of this form of sexual behavior is greater genetic diversity, less need for males to compete with each other, and greater protection for, and nurturing of, the young. |
Proboscis | An elongated appendage from the head of an animal, either a vertebrate or an invertebrate. In invertebrates, the term usually refers to tubular mouthparts used for feeding and sucking. |
Protocercal | A type of caudal fin in which the vertebrae extend to the tip of the tail and the tail is symmetrical but not expanded (as in lancelets) |
Pupa | The life stage of some insects undergoing transformation. The pupal stage is found only in holometabolous insects, those that undergo a complete metamorphosis, going through four life stages: embryo, larva, pupa and imago. Pupae may further be enclosed in other structures such as cocoons, nests or shells. |
Raceme | A spike-like inflorescence, with stalked flowers arising from a central axis |
Rhizome | A modified subterranean stem of a plant that develops from axillary buds and is usually found underground, often sending out roots and shoots from its nodes |
Roe | The fully ripe internal egg masses in the ovaries, or the released external egg masses of fish and certain marine animals |
Rootstock | See Rhizome |
Rosette | A cluster of leaves or other plant parts arranged in a circle, often at the base |
Ruderal species | A plant species that is first to colonize disturbed lands, whether the disturbance be natural or manmade |
Runner | See Stolon |
Samara | A dry, closed, winged fruit |
Sapwood | The outer portion of a woody plant’s trunk or branch, between the heartwood and the bark; the living part of the wood |
Schizocarp | A dry fruit that, when mature, splits up into mericarps |
Sepal | The outermost whorl of parts that form a flower. Typically function as protection for the flower in bud and often as support for the petals when in bloom. |
Shoot | Consist of stems including their appendages, the leaves and lateral buds, flowering stems and flower buds. The new growth from seed germination that grows upward is a shoot where leaves will develop. |
Silique | An elongate capsule that splits along the sides |
Spike | An elongate inflorescence with sessile or barely stalked flowers arising from a central stalk |
Spikelet | A small spike, often in grasses and sedges |
Stamen | The pollen-producing reproductive organ of a flower |
Stenohaline | Tolerating a very narrow range of salinities |
Stipules | Paired scales, spines, glands, or blade-like structures at the base of a petiole |
Stolon | A stem which grow at the soil surface or just below ground that form adventitious roots at the nodes, and new plants from the buds |
Submergent | Referring to an aquatic plant, growing under water |
Sucker | A plant growing not from a seed but developed of a meristem from the root at the base or at a certain distance of a tree or shrub. It is a form of vegetative reproduction. |
Taproot | A primary root that more or less enlarges and grows downward into the soil |
Telescoping generations | An occurrence in which a viviparous female has a daughter growing inside her that is also parthenogenetically pregnant with a daughter cell |
Tendril | A thigmotropic organ which attaches a climbing plant to a support, a portion of a stem or leaf modified to serve as a holdfast to other objects |
Terminal bud | A bud occurring at the tip of a stem |
Tuber | An enlarged stem or root that stores nutrients |
Turion | A small bulb-like structure; a type of bud that is capable of growing into a complete plant. A turion may be an underground bud. |
Vegetative fragmentation | See Fragmentation |
Ventral fins | See Pelvic fins |
Viviparity | Development of the embryo inside the body of the parent, eventually leading to live birth, as opposed to reproduction by laying eggs that complete their incubation outside the parental body |
Zoochory | The dispersal of seeds of a plant by animals. Includes epizoochory (on the outside of animals (such as the seeds of houndstongue)) and endozoochory (via ingestion of seeds (such as autumn olive and common buckthorn)). |