Specimens featured in the fluorescence digital image gallery are derived from a combination of stained thin sections, whole mounts, suspensions, smears, and several additional mounting techniques. Stained tissue culture cells and thin sections were labeled with either fluorescent dyes or common histology stains such as eosin, fast green, and safranin. Fluorescence microscopy and photomicrography was conducted by Charles D. Howard. Background research for the figure captions was provided by Elise Sessions. Kathleen Carr supervised the authoring and assembly of text for each of the gallery entries.

Fluorescence Microscopy of Cells in Culture - Serious attempts at the culture of whole tissues and isolated cells were first undertaken in the early 1900s as a technique for investigating the behavior of animal cells in an isolated and highly controlled environment. The term tissue culture arose because most of the early cells were derived from primary tissue explants, a technique that dominated the field for over 50 years. As established cell lines emerged, the application of well-defined normal and transformed cells in biomedical investigations has become an important staple in the development of cellular and molecular biology. This fluorescence image gallery explores over 30 of the most common cell lines, labeled with a variety of fluorophores using both traditional staining methods as well as immunofluorescence techniques.

Alfalfa Root - Alfalfa, or Medicago sativa, is a deep-rooted perennial native to the Mediterranean region near Iran but which also grows well in North America and Western Asia. Also called Lucerne, or Purple Medic, it looks very much like clover with a smooth, erect stem growing 2 to 3 feet tall, grayish-green feathery trifoliate leaves, and egg-shaped leaflets. It is tolerant of a wide range of climatic conditions and can be grown in cool, humid environments as well as irrigated arid regions.

American Dog Tick - The American dog tick is one of the ticks that harbor the organism that causes Rocky Mountain spotted fever, the most common tick-borne disease in the United States. The illness was first spotted in Montana and Idaho, although it is now prevalent in the southeast. Symptoms include sudden high fevers, severe headaches, fatigue, muscle aches, nausea, and sometimes rashes. Usually symptoms become apparent 3 to 12 days after the victim has been bitten.

Ant (Formicidae) - Ants are one of the most successful groups of insects to inhabit the Earth during the past 100 million years. All ants belong to the insect family Formicidae in the order Hymenoptera, the same order comprising bees and wasps, and are believed to have descended from a wasp-like ancestor. The social behavior of ants, which exhibit a predominately female society made up of three castes, is one of the most complex of the insects.

Antelope Hair - Antelopes are even-toed ruminants belonging to the family Bovidae, order Artiodactyla. This family includes bison, buffalo, cattle, sheep and goats. Antelopes are herbivores, native to Africa and parts of Asia. Pronghorn antelopes, which belong to the family Antilocapridae, are native to North America, but are not true antelopes because they annually shed the outer sheath of their branched horns unlike other antelope species.

Basswood (Tilia) Root - Basswood trees are characterized by tall, straight trunks and a deep wide-spreading root system that makes them less vulnerable to wind than many other species. The American basswood, scientifically described as Tilia Americana, is also renowned for its heavy foliaged crown that features dark green heart-shaped leaves that reveal more lightly colored glistening undersides when rustled by a breeze. The hardwood tree is well suited for growth in the fertile soils of the northeast United States, where it proliferates in great numbers as a favorite ornamental shade tree.

Basswood (Tilia) Stem - Basswood seeds and twigs are a popular food for wildlife and the flowers smell and taste like honey, attracting over 60 insect pollinators, especially honeybees. The soft, light-colored wood has an even grain, long favored by wood carvers. Native Americans used the fibrous inner bark to make rope, which was used to bind wounds and stitch mats made from cattail leaves.

Bed Bugs (Cimex lectularius) - Bed bugs feed primarily on human blood, but can be found on bats, rabbits, domestic animals, and other warm-blooded mammals. They also have the ability to survive long periods of starvation and adverse temperatures. Bed bugs are mentioned in early European history and literature and are believed to have been transported around the world by clothing and bedding. Today, they are found in both temperate and tropical regions.

Bird Lungs - At rest, a bird's oxygen consumption rate is higher than all other vertebrates. That rate is even higher when engaging in activities such as flying. Birds are capable of high rates of gas exchange because of the special construction of their lungs, and additional breathing organs, a complex series of air sacs. Connecting tubes join the lungs to these air sacs, increasing a bird's respiratory capacity to about twice that of any mammal of comparable size.

Bird Skin - Birds have a thin and delicate epidermis, or skin, compared to other vertebrates. Their skin produces specialized structures called feathers, which is one of the unique characteristics of birds. Feathers are made up of keratin, a flexible protein that also forms the hair and fingernails of mammals. Over the past 100 million years, feathers have evolved a variety of forms. Thick epidermal scales, like those found in reptiles, usually cover exposed areas of skin, such as the legs and feet.

Black Grape Rot - Black rot, caused by the fungus Guignardia bidwellii is one of the most serious diseases of cultivated grapes in the eastern United States, especially in warm, humid areas. Crop losses due to black rot can be devastating, ranging from 5 to 80 percent depending on the weather, the variety of grape being grown, and the amount of disease in the vineyard. The fungus can infect all green parts of the vine but the most damaging effect is on the fruit, which shrivel up into dark-colored mummies.

Cactus - Cactus plants are perennial succulents native to the Americas and easily grown in almost all warm and arid climates around the world. The ability to sustain extreme temperatures makes them one of the heartiest plants on earth. Thorns, hairs, and layers of wax are some of the characteristics of cactuses that help to maintain their core temperature. Large systems of roots and fleshy stems help the cactus plants to absorb large quantities of water when available and store it through long periods of drought.

Clubmoss (Lycopodium) - Historically, clubmosses have endured many climatic and environmental changes. The plants were particularly abundant hundreds of millions of years ago during the Paleozoic era, when they grew to massive proportions and dominated the Earth. Today, clubmosses are much smaller and are primarily native to mountains in the tropics, though they may also be found in northern forests. The exact dimensions of the plants are dictated by species, but a typical example is stag's horn moss (L. clavatum), which features creeping stems about 10 feet long and has approximately 4-inch-high ascending branches.

Corn Grain - Corn is the common name for the cereal grass widely grown as food for humans and animals. Along with wheat and rice, it is one of the world's chief grain crops and the largest crop grown in the United States. Native to the Americas, corn (Zea mays) is the domesticated variety of the Zea grass family, originally cultivated by Native Americans 8,000 to 10,000 years ago. There are many varieties of domestic corn, most of which were developed through the aggressive breeding programs of the twentieth century.

Corn Smut - Smut is a disease of cereals, corn, grasses, onions, and sorghum that can be caused by any of more than 700 species of parasitic fungi. Smuts generally have a negative economic impact on agriculture, because they affect so many food crops. An exception to this is corn smut, which is considered a delicacy in Mexico. In the United States, after decades of trying to eradicate corn smut, some farmers are attempting to grow corn with large corn smut infestations because the fungus is becoming a prized gourmet food item, garnering much higher prices than healthy corn.

Dogfish Shark Placoid Scales - The bodies of dogfishes, like all sharks, are externally lined with placoid scales, also known as dermal denticles. The scales, which unlike other types of fish scales do not get larger as the shark grows, are similar in structure to teeth, consisting of three layers: a hard outer enamel-like layer, a middle stratum of dentine, and a central vascular pulp cavity. The scales are arranged in a slanting pattern pointed towards the tail of the shark that helps decrease the amount of friction the animal incurs while swimming. If the surface of a shark is rubbed from head to tail, it feels smooth, but stroking the animal in the opposite direction causes it to feel very rough.

Down Feathers - Down feathers are the soft, fluffy feathers that first appear on young birds and that also form the protective undercoat of many avian adults. Slightly different in structure, down feathers do not feature the interlocking barbs that help give other types of feathers their strength. However, since their primary function is to provide warmth and insulation, their relative weakness is inconsequential. In fact, down feathers are so well-suited to their role as insulators, humans often utilize them to stuff winter coats and bedding, such as comforters and sleeping bags.

Dutchman's Pipe - A native of central and eastern North America, Dutchman's pipe, Aristolochia durior, is a climbing vine and part of the birthwort family. The vine is planted often as a screen or cultivated as a porch vine because it is easy and quick to grow. It is distinguished by its large heart-shaped leaves and yellowish or purplish tubular flowers that resemble traditional Meerschaum smoking pipes. One curious attribute of the flowers is that they give off an aroma reminiscent of rotting meat.

Elderberry (Sambucus canadensis) - About 30 species of Elderberry make up the genus Sambucus of the family Caprifoliaceae. Elderberry bushes can be found in most forested temperate or subtropical areas around the world. In horticulture, the bushes are often used as garden shrubs and are well known for their fruit, which is used to make wines, syrups, cordial, jellies, pies and also serves as a source of food for wildlife.

Fava Bean Root Tip Mitosis - The fava bean plant (Vicia faba) also known as broad bean or horse bean, is a legume belonging to the pea family, Fabaceae. It is cultivated for its seeds, six to eight beans resembling large round limas, packed inside a large, pale-green, velvety pod. Fava beans have been an important crop in the Mediterranean area and Asia since the late Neolithic period, about 3,000 BC. Today, it has achieved a wide distribution throughout the temperate regions of the world and is one of the most important winter crops for human consumption in the Middle East.

Female Pine Cones - Pine trees are gymnosperms, non-flowering plants that produce exposed seeds not enclosed in an ovary. They are also monoecious, bearing gametes of both sexes on the same tree. These gametes are housed in a structure called a strobilus, or cone. Female pine cones are generally found in the upper branches of the tree crown, above the male cone. This reduces the possibility of self-fertilization by the wind-borne male gametes.

Fern Spores - Fern is a common name for the cryptogamous (spore-producing) plants belonging to the division Filicophyta, also called Filicinophyta. They are primitive vascular plants with true roots, stems, and complex leaves. Most ferns reproduce through the alternation of generations, alternating successive generations of sexual and asexual forms. The sexual form, called the gametophyte or prothallia, is a tiny kidney-shaped plant and difficult to find in the wild. The asexual form, known as a sporophyte, is represented by the fern plant as it is commonly known.

Fish Gill Filaments -Unlike land vertebrates or marine mammals, fish don't have lungs, but they do have paired respiratory structures called gills, or branchia. Outgrowths of the body wall, gills remove dissolved oxygen from water and expel carbon dioxide waste from the bloodstream. This is how fish can breathe underwater without ever having to come to the surface for air. When there are insufficient quantities of dissolved oxygen in the water, they will suffocate.

Fleas - Ctenocephalides felis is commonly known as the cat flea and Ctenocephalides canis is known as the dog flea. Both are members of the 1,600 species referred to as fleas, order Siphonaptera ("wingless siphon"). Adult fleas vary in length from 0.04 to 0.4 inches and are able to jump over eight inches high, which is roughly the equivalent of a human jumping over the Statue of Liberty. These blood-sucking insects can be found worldwide, from the Arctic to the tropics.

Frog Stomach Thin Section - In amphibians known as gastric brooding frogs the stomach is more than just a place for digestion to take place. The females of these species swallow their clutch of eggs and allow the tadpoles to hatch in their stomachs. It is believed that the tadpoles secrete chemicals that inhibit the production of hydrochloric acid in the stomach wall and cause the mother to desist from feeding. Once the tadpoles become fully developed froglets, they are birthed through the mouth of the mother. Scientists have been extremely interested in studying these animals in order to find information about hydrochloric acid determent that could benefit humans suffering from gastric ulcers.

Guinea Pig Hair - The guinea pig (Cavia porcellus) is a domesticated form of the cavy and is native to in South America. It is believed to have been domesticated during pre-Incan times from a wild species that lived in Peru. The animal is not, in fact, a pig but is a rodent, a relative of mice, rats and hamsters. Like other rodents, guinea pigs' teeth do not have nerves and grow continuously, like fingernails.

Head Louse - There are three species of louse that parasitize humans: the head louse (Pediculus humanus capitis); the body louse, better known as the cootie (P. humanus humanus); and the crab, or pubic, louse (Phthirus pubis). These species belong to the insect order Anoplura and have long been associated with people. Archaeologists have even found louse combs buried with Egyptian mummies, who were apparently anticipating head lice in the afterlife.

Herbaceous Stems - The stems of herbaceous plants tend to be somewhat soft and flexible because they contain very little of the woody material characteristic of bushes and trees. Instead, they are primarily composed of vascular bundles (xylem and phloem) arranged in a circle around a central core of spongy tissue made up of parenchyma cells, or pith. A layer of tissue known as the cortex surrounds the vascular bundles and may vary in thickness depending upon species. Another layer of cells called the epidermis encircles the cortex. In conjunction, the various materials of the stem carry out the structure's primary functions, which include providing support to leaves and flowers, as well as transporting water, minerals, and the products of photosynthesis throughout the plant.

Honeybee Leg - Honeybees are classified in any of the four species that belong to the genus Apis. They are classified, along with 20,000 other insect species, as members of the Apoidea superfamily (order Hymenoptera), which includes ants, wasps, hornets, and many other species of bees. A honeybee's body is divided into three segments, each one equipped with a pair of legs. Each pair of legs is highly specialized and, in combination, they make the perfect tools for collecting pollen, which provides essential proteins for honeybee larvae.

Honeybee Stinger - The stinger is located on female honeybees at the end of the abdomen and is part of the ovipositor, which is an egg-laying device. Even though most bees can sting repeatedly, a honeybee only has one chance. The honeybee stinger has a hook-shaped barb and when it catches in a victim the bee can't fly away without inflicting the fatal wound of tearing out its ovipositor along with some internal organs. Even after the bee detaches itself, the venom sac and its attached muscles continue to pump venom into the victim.

Horsetail (Equisetum) Plants - Although many horsetails have little commercial value, some have been utilized by humans for thousands of years. The horsetail scientifically described as E. arvense has been used as an herbal remedy since the early days of ancient Greece and Rome. Traditionally the plants were employed to promote blood clotting and to treat kidney infections and tuberculosis. Another useful type of horsetail is commonly known as the scouring rush. The coarse, textured plant contains a significant amount of silica granules in its cells that make it a valuable for scouring or as an ingredient in abrasive powders.

House Fly Face - The often maligned common house fly is generally thought to be a nuisance and vector for many diseases that affect both humans and animals. Flies lay up to 1000 eggs in some of the most undesirable settings such as garbage, decomposing plant and animal matter, feces, spoiled food, and manure. Although more abundant in the warm spring and hot summer weather, house flies may exist year-round in temperate climates, where their life cycles occur every eight days.

House Fly Mouth - A closer view of the house fly face, this time peering deep into the insect's mouth. Although some flies can bite, the house fly cannot. Its mouthparts consist of soft, spongy structures called the labella and proboscis. The labella gently dab liquids into its proboscis, which then sucks up the liquid. If the fly encounters solid food it wants to eat, it drops saliva onto it, turning the food into a liquid.

Human Flea - Fleas belong to the insect order Siphonaptera and parasitize mammals and birds for their blood, using specialized anatomical structures to attach to the hosts' skin. Pulex irritans, the human flea, is one of more than 1,600 species and subspecies of fleas that populate the Earth from the Arctic Circle to the deserts of Africa. As its common name suggests, the preferred food for Pulex is human blood, but it will feed on other mammals as well.

Human Hyaline Cartilage - Cartilage is a dense network of collagen fibers, embedded in a firm but plastic-like gelatinous substance, covered by a membrane called the perichondrium. Mammals have three types of cartilage: hyaline, elastic, and fibrocartilage. Hyaline cartilage is the most widely distributed form and is also the type that makes up the embryonic skeleton. In adults, it's found at the ends of bones in free-moving joints and at the ends of the ribs, and also in the nose, larynx, trachea and bronchi.

Human Roundworm - Ascaris lumbricoides, the large human roundworm, is the most massive nematode to parasitize humans, growing up to 16 inches long and often as thick as a pencil. Infections of this intestinal roundworm, called ascariasis, are extremely common in rural communities around the world and affect as many as 1.5 billion people, almost one-quarter of the world's population. Infections occur after people ingest food or soil contaminated with Ascaris eggs.

Human Scalp - In humans, the scalp is a specialized area of skin on top of the head, usually covered with hair in both sexes. It consists of three layers: a layer of skin, an underlying layer of tissue and blood vessels, and the occipitofrontalis muscle, which raises the eyebrows, stretching from the top of the eyebrows to the back of the head. The scalp covers most of the head, starting at the top of the forehead, and contains as many as 150,000 hair follicles.

Human Spinal Cord - The human nervous system carries stimuli from sensory receptors to the brain by two main parts: the central nervous system and the peripheral nervous system. The brain and spinal cord make up the central nervous system. The spinal cord represents the major nerve track in all vertebrates. In humans, the spinal cord extends from the base of the brain to the middle of the back and is about 18 inches long.

Japanese Pony Belly Hair - Hair is a unique attribute of mammals and serves a variety of functions, although the primary function of hair is to preserve body heat. Japanese ponies are particularly famous for their hair. Its soft and luxurious feel to the skin has made Japanese pony hair a favorite in the world of cosmetics, used for powder brushes and other face brushes. Recently the pony hair market has expanded to include clothing, shoes and even toys.

Kapok Fiber - Kapok fiber is a silky cotton-like substance that surrounds the seeds in the pods of the ceiba tree. The ceiba tree belongs to the Bombacacae family and is primarily found in Asia in tropical and semi-tropical climates, at an altitude less than 1000 feet, in porous volcanic soil. The fiber is removed by hand, dried, separated from the seeds and prepared for export. It is too brittle and inelastic to be spun, but it is ideal for stuffing life preservers and other water-safety equipment because of its excellent buoyancy.

Leech - Leech is a common name for over 650 species of carnivorous, bloodsucking annelid worms that make up the class Hirudinea of the phylum Annelida. They are equipped with a large and a small sucker. The mouth is located on the small sucker and has three jaws with sharp teeth that make a y-shaped incision in the flesh. When a leech punctures the skin it anesthetizes the wound with its saliva, so that often the victim does not feel a thing.

Lily Flower Bud - Richly symbolic, lilies have a long history of special significance to humans. Minoans believed the plants were sacred and associated them with their goddess Britomartis. In fact, Minoan artifacts exhibiting representations of lilies have been discovered that date back to around 1580 BC. Ancient vases and relics etched with lilies have also been found in Egypt, where the plants were often revered as symbols of light. In ancient Greece and Rome, however, lilies were emblematic of innocence and were woven into crowns worn by brides during their weddings, a tradition carried over into modern times by brides carrying lily-filled bouquets.

Lily Seeds - Lilies are herbaceous flowering plants that thrive in warm temperate and tropical climates. As monocots, the bisexual lily buds typically exhibit three sepals, three petals, and six stamens, each bearing a bilobed anther containing four pollen sacs. Additionally, the buds feature a single central pistil leading to an ovary, usually with six ovules, which is enclosed by three fused carpals. Although sexual reproduction by seed is possible, lilies are usually commercially grown via asexual bulbs to ensure that the plants maintain enough energy for flowering.

Lone Star Tick - Amblyomma americanum is commonly known as the Lone Star tick. It's named for the dramatic iridescent spot that can be found on the female. Lone star ticks are found primarily in northern and central Florida, but can also be found in the mid-Atlantic and south-central parts of the United States, as well as Mexico. The ticks are reported to transmit Rocky Mountain spotted fever, Q fever, tularemia, and Lyme disease.

Mammalian Compact Bones - There are two basic structural types of bone in mammals, compact and spongy. Compact bone is very dense and hard on the outside, and makes up most of the bones in the arms and legs. The structural units are osteons, which are elongated cylinders acting as weight-bearing pillars that can withstand high levels of mechanical stress.

Mammalian Spongy Bone - Spongy bone, also known as cancellous bone, is less dense than compact bone and is composed of a honeycomb-like network of bones called trabeculae. Spongy bone actually looks like a sponge. It is found at the expanded heads of long bones, such as bones of the arms, legs, fingers and toes. The material also fills most irregular bones, such as bones of the skull, vertebrae and hips.

Milkweed Fibers - Milkweed is a perennial plant whose species are native primarily to North America. It can be found growing in prairies, pastures, along roadsides and on the banks or edges of ponds and lakes. As suggested by its name, milkweed contains an abundance of milky sap in its leaves, stems and pods. A healthy plant can reach nearly 5 feet, thriving in full to partial sun in all types of soil.

Mite - There are over 20,000 species of mites, tiny anthropod invertebrates belonging to the class Arachnida. Along with the tick, they make up the order Acarina. Mites can be found worldwide in diverse habitats, including brackish water, fresh water, hot springs, soil, plants, and mosses as well as upon and inside animals. Parasitic forms may live in the nasal passages, lungs, stomach, or even deeper body tissues.

Mosquitoes - Despite the bad reputation of mosquitoes, male mosquitoes do not bite, but harmlessly feed upon plant and fruit juices. It is only the females who require blood meals, due to a need for extra protein to produce eggs. In order to locate their victims, the females utilize a variety of cues, including sight, scent, and heat. From as many as 100 feet away, the insects are capable of detecting the scent of potential hosts, especially the carbon dioxide they exhale.

Moss Reproductive Tissue - Mosses are the most common, diverse, and advanced group of bryophytes, a division of green, seedless plants that dates back to the Permian period (286 to 245 million years ago). In Bryophytes, the antheridium is the male sex organ, which produces sperm. The archegonium is the female reproductive organ, which produces eggs. Both types of reproductive tissue are generally found at the tips of the main plant shoots.

Mouse Intestines - Laboratory mice are special breeds of house mice and are used in many scientific experiments because of their close mammalian relationship to humans. Mouse intestines, for instance, are very much like those of other vertebrate animals. The large intestine is wider and shorter than the small intestine and its primary function is to absorb water and electrolytes from digestive residues and store fecal matter.

Mouse Kidney - The kidney is an organ that maintains water balance and expels metabolic wastes in vertebrates and some invertebrates. Primitive and embryonic kidneys have sets of specialized tubules that empty into two collecting ducts that pass urine into a primitive bladder. The more advanced mammalian kidney is a paired compact organ with functional units, called nephrons, that filter the blood, reabsorbing water and nutrients and secreting wastes, producing the final urine.

Mycorrhizal Fungi - Most plant species are better able to utilize the soil in which they're growing with the help of beneficial microorganisms called mycorrhizal fungi. These fungi live in symbiosis with plants, growing on the surface of their roots (ectotrophic) or actually invading the hosts' roots (endotrophic). The fine threads that make up the mycorrhizal fungus permeate soil particles, grow into decomposing organic matter, and even explore the shells of dead insects where they find phosphorus and other vital nutrients. The nutrients absorbed by the fungi are then passed back into the roots of the plants providing a major benefit to the plant--improved uptake of soil phosphorus.

Obelia Hydroid: First Generation - Obelia belongs to the phylum Cnidaria, which includes corals, sea anemones, jellyfish, and the freshwater hydra. The many species of this genus are widely distributed throughout all the oceans and are typical of cnidarians, both in their morphology and their life cycle. These animals take two generations to complete one life cycle, one of which consists of polyps living in hydroid colonies.

Oleander Leaf - Oleander, Nerium oleander, is an ornamental evergreen that belongs to the dogbane family, Apocynaceae. The plant is beautiful, but extremely deadly. A single leaf can kill an average size adult. In fact, all parts of the plant are highly toxic if ingested. Oleander contains a poisonous glycoside, a milky substance that is rich in salicine and other alkaloids. This poisonous sap can paralyze the hearts of humans and animals.

Peach Brown Rot Fungus - Peach brown rot is a serious disease of fruit trees caused by the fungus Monilinia fructicola. Also affected by this devastating fungus are other stone fruits such as cherries, plums, prunes, nectarines, and apricots. The fungus forms cankers on the twigs of the fruit trees, but it does the most damage when it rots blossoms and fruit. At harvest, apparently healthy fruit may be contaminated with spores and decay during storage and marketing.

Peach Leaf Curl - Peach leaf curl is a common disease of peach and nectarine trees caused by the fungus Taphrina deformans. Spores of the fungus overwinter on the surface of peach twigs. In spring, the spores multiply during periods of moist weather until the leaf buds swell and open. Rain is necessary for infection, carrying the spores on a thin film of water into the buds, where leaves are infected. After the deformed and discolored leaves turn brown and fall, they produce powdery gray spores.

Pectinatella Bryozoans - Colonies of Pectinatella species and other bryozoans increase rapidly in size, sometimes doubling in diameter over the course of a few days if proper conditions and abundant food are present. P. magnifica prefers warm temperatures and feeds on small aquatic plants and animals such as diatoms, algae, and bacteria. To do so, the zooids utilize specialized feeding structures known as lophophores that are ciliated and can be extended or retracted as needed. If the environment becomes unfavorable, however, perhaps due to the approach of winter, the colonies produce statoblasts, which are more able to withstand extreme conditions.

Pine Needle Cross Section - Due to the efficiency of their needles, pine trees remain covered in leaves year-round and are commonly known as evergreens. Older needles drop off periodically (usually when they are two to four years old), but they are continuously replaced with new growth. The needles grow in sheathed bundles, arranged spirally along supporting shoots. The number of needles in each bundle may vary, but they generally contain two to three needles on hard pines and five on soft pines.

Pine Root - The root system is the part of a plant that normally grows underground. Its primary functions are anchorage of the plant, absorption of water and dissolved minerals, conduction of these to the stem, and storage of reserve foods. Gymnosperms, such as pine trees, have a taproot system. A primary root, or taproot, emerges from the seedling and secondary roots grow laterally from it. The taproot grows deep into the ground, enabling the tree to withstand long periods of drought.

Pine Tree Pollen - Pine trees are gymnosperms, nonflowering plants that produce exposed seeds not enclosed in an ovary. These gametes are housed in a structure called a strobilus, or cone. The male pinecone produces the pollen, or male gametes. The cones are covered with fertile scales (modified leaves), each of which bears two pollen sacs. In the spring or early summer, the pollen sacs release their pollen grains, each of which has two air bladders for wind dispersal.

Pine Wood - Pine is the common name for species belonging to the genus Pinus, a member of the family Pinaceae, resinous trees with needle-like leaves. Pine trees are evergreens found worldwide, primarily in northern temperate regions. Typically they have woody stems covered in bark, which protects tissues that conduct nutrients and water. When harvested, they provide materials like lumber, turpentine, rosin, paper, pulp, fuel and even food (pine nuts).

Privet Leaf - About 50 species of privet shrubs and small trees belong to the genus Ligustrum of the Olive family, Oleaceae. They grow quickly and are popularly used as hedges and screens. Privets are native to Europe, Asia, and the Mediterranean regions. Their flowers bloom in clusters, or panicles, of small white blossoms.

Raw Meat - For millions of years, the human diet has included the edible portion of animal tissues, or meat. Meat is an excellent source of protein, providing all nine essential amino acids in addition to vitamins and minerals. There are three types of muscle: smooth, cardiac, and skeletal, but skeletal muscles make up most meats and meat products.

Rhizopus Rot - Rhizopus rot is a soft rot of harvested or over-ripe stone fruits, such as peaches, nectarines, sweet cherries, and plums. Mold species belonging to the genus Rhizopus cause the rot, which initially appears on the fruit as a fuzzy white mass called the mycelium. The fungus produces enzymes that deteriorate the tissue holding the skin to the flesh of the fruit. Later, it turns dark gray to black as the fungus begins to develop sporangia, the fruiting structures that produce spores.

Smilax Root - Humans have utilized Smilax vines for a variety of purposes throughout history. Some types are edible, while others, such as the carrion flower (S. herbacea) and the common greenbrier (S. rotundifolia) are cultivated to create impenetrable thickets. The desirability of using carrion flowers as ornamentals, however, is questionable due to their blossoms, which are reminiscent of rotting meat and are pollinated by flies. Also, the perennials can cause problems when they invade crops of fruit, a fairly frequent occurrence in the southeastern United States.

Snail Radula - Snails have a large foot for creeping along surfaces, a single coiled shell that encloses the organs, and a head with eyes and tentacles. Like most other gastropods, snails feed by using a specialized rasping organ called a radula. It is a ribbon-like structure covered with small horny teeth called denticles that tear food into pieces that are then collected by lips or a proboscis. New denticles are constantly being produced to replace those worn away at the front.

Sweet Flag Grass - Sweet flag, taxonomically classified as Acorus calamus, is a grass-like perennial that can grow up to 2 meters or 6.6 feet high. Along with the common cattail, sweet flag thrives in wet areas like the edges of streams, ponds, and lakes. The thick, erect leaves of the plant resemble those of an iris and, though it rarely flowers, its blossoms are greenish brown cylinders covered in little, rounded spikes.

Trichina Worm - Trichina (Trichinella spiralis) is a parasitic nematode worm that causes trichinosis, a serious disease in humans and other meat-eating mammals. The most common way that humans become infected with trichinosis is by eating raw or undercooked pork. People can also become infected by eating wild game, such as bear, cougar, fox, dog, wolf, horse, seal, or walrus. As of now, there is no known specific treatment for trichinosis, but it can be prevented.

Wheat - Wheat is the common name for any of the cereal grasses belonging to the genus Triticum and is an important food source for people around the world. In fact, it is the most common grain cereal today, world wheat production totaling more than 590 million metric tons in 1990. Evidence shows that wheat grew as a wild grass in the Middle East nearly 10,000 years ago and was in cultivation by 6,000 BC.

Wheat Kernel - Wheat grains can be eaten by simply soaking and cooking the grain. The majority of food uses, however, require more processing. First, the grain is cleaned and conditioned by adding water. This causes the kernel to break up properly when it is milled. During the milling process, the grain is cracked, then flattened by rollers. This process continues and particles are sifted by size until about 70 percent of the grain has been powdered into flour.

Wheat Rust Pustule - Wheat rust is a common and serious disease, reducing crop yields both in the United States and in other wheat-growing areas of the world. It is caused by a parasitic fungus and can affect both the leaves and stems of wheat plants. In individual fields, the disease accounts for crop losses ranging from trace amounts to as much as 40 percent when weather conditions are favorable for fungus growth.

Young Starfish - Despite their name, starfish are echinoderms, not fish. They breathe through structures on their hard, spiny skin rather than gills and move through the use of the rows of tube feet that line the bottom of each of their arms instead of swimming. The tube feet are also utilized for detecting smells and tastes, as well as for sweeping food into the mouths of primitive starfish species. Most of the more advanced varieties of the creatures, however, protrude their stomachs out of their mouths to surround prey.

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