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This group of flowering plants (angiosperms), with one seed leaf, was previously thought to be one of the two major categories of flowering plants (the other group is dicotyledons). However, deoxyribonucleic acid (DNA) studies have revealed that,…

A macroscopic fungus with a fruiting body. It has been estimated that 1.5 million to 5 million species of fungi exist on Earth. Yet, only about 120,000 species have been described to date. Approximately 50,000 fungal species are considered…

The science of mushroom-derived products used for medical and pharmaceutical purposes. Medicinal mushrooms have an established historical use in traditional ancient therapies. Contemporary research has validated and documented much of the ancient…

The study of organisms of the fungal lineage. Mycology is the scientific discipline concerned with all fungal organisms, including mushrooms (see illustration), boletes, bracket or shelf fungi, powdery mildew, bread molds, yeasts, puffballs, morels,…

An order of flowering plants, division Magnoliophyta (Angiospermae), in the subclass Hamamelidae of the class Magnoliopsida (dicotyledons). The order consists of the single family Myricaceae, with about 50 species. Within its subclass, the order is…

An order of flowering plants in the core eudicots. The order consists of 10 families and approximately 9300 species. The circumscription of the order has been relatively stable, with only minor changes made on the basis of deoxyribonucleic acid…

An order of flowering plants, division Magnoliophyta (Angiospermae), in the subclass Dilleniidae of the class Magnoliopsida (dicotyledons), but whose members have now been typically reassigned to other plant orders. The order Nepenthales (also known…

Any of various evergreen trees of the genus Citrus, cultivated for its edible fruit. Orange trees (genus Citrus) belong to the family Rutaceae of the order Sapindales. The various trees classified as orange trees are most notable for producing…

Plants that are grown and used for decorative or display purposes. The use of ornamental plants (also termed ornamentals) [see illustration] developed early in history for it is known that primitive peoples planted them near their dwellings. There…

A deadly fungal disease of bananas caused by a soilborne fungus. Panama disease, also known as Fusarium wilt of bananas (Musa species), is one of the most destructive fungal diseases of plants (Fig. 1). It is caused by a soilborne fungus, Fusarium…

The principal food-conducting tissue in vascular plants. The long-distance transport of nutrients in plants occurs in the phloem, which is a highly specialized tissue that links all the organs of the plant. The conducting cells of phloem are known…

Natural substances that are toxic to microbial pathogens and are synthesized by plants as a defensive response to infection. Phytoalexins comprise an important group of natural compounds manufactured by plants in response to pathogenic intrusions…

Plant chemicals, defined as bioactive nonnutrient plant compounds in fruits, vegetables, grains, and other plant foods, that have been linked to the reduction of risk for major chronic diseases. Plant-based foods, such as fruits, vegetables, and…

A photoreceptor (protein pigment) used by plants and other photosynthetic organisms to detect light. Phytochromes are protein-pigment photoreceptors (Fig. 1) that control most photomorphogenic responses in various biological organisms that utilize…

The use of plants to clean up environmental contamination of surface soils. Phytoremediation is more cost-effective and environmentally appealing than other currently available methods for soil detoxification. The most common approach for soil…

An order of the plant class Pinopsida (Coniferopsida) within the division Pinophyta (Gymnospermae). All members of the Pinales, often termed conifers, are woody plants. They comprise trees or shrubs, and are often the principal trees of the forests…

One of the major divisions of the seed plants. The most familiar and common representatives of the division Pinophyta are the evergreen, cone-bearing trees of the order Pinales (within the class Pinopsida). Members are known colloquially as…

The single class of the division Pinophyta (Gymnospermae). The class Pinopsida contains both living and fossil taxa. The living representatives of the Pinopsida are woody plants; most are trees with a central axis and excurrent branches. Leaves are…

Movement of signals or cues, chemical in nature, among individual plants or plant parts. Plant communication is a phenomenon of chemical ecology (see illustration). In particular, chemical cues or signals are released by plants in response to damage…

The collective processes involved in plant assimilation and metabolism of all chemical elements, with the exception of carbon, hydrogen, and oxygen. Plants obtain most of their mineral nutrients by extracting them from solution in the soil or the…

Plant parts having rather distinct form, structure, and function. Plant organs are the key anatomical features of plants. They include the aboveground leaves, stems, and reproductive structures of the plant's shoot system, as well as the belowground…

A substance in a plant that imparts coloration. Plant pigments are important colored substances produced by plants. There are both photosynthetic and nonphotosynthetic pigments in plants. Chiefly, the photosynthetic pigments are involved in light…

The deliberate, directed reproduction of plants using plant cells, tissues, or organs. Plant propagation is the planned operation of creating new plants through natural or artificial means. In general, plant propagation can be accomplished by using…

The formation of a new plant that is either an exact copy or recombination of the genetic makeup of its parents. There are three main types of plant reproduction: (1) vegetative reproduction, in which a vegetative organ forms a clone of the parent;…

Aggregations of similar plant cells that perform a specific function for the plant. Plant tissue systems are the structural and functional tissue systems of plants. These tissue systems are organized into three entities: the dermal tissue system,…

The relationships between plants and water, including the hydration of plant cells and the transport of water within a plant. Water is the most abundant constituent of all physiologically active plant cells. Leaves, for example, have water contents…

Plants that grow well in soils having a high salt content, referred to as halophytic plants. Plants of saline environments (halophytes) constitute approximately 1% of the world's flora and have evolved to flourish in locations where the soil salt…

Commonly encountered plants that produce an oil called urushiol, which triggers allergic contact dermatitis in humans. Poison ivy (Fig. 1), poison oak (Fig. 2), and poison sumac (Fig. 3) are the best-known poisonous plants in North America, blamed…

Plants that produce biochemical compounds harmful to humans and other animals. While mechanical injury—for instance, from thorns—is probably the most common cause of human injury from plants, a great number of plants (Fig. 1) can cause injury…

The transport of pollen grains from the plant parts that produce them to the ovule-bearing organs, or to the ovules (seed precursors) themselves. Pollination is a process that ensures the successful life cycle of plants. Without pollination, there…

An extinct order of the class Lycopsida (clubmosses) of the Devonian Period. Most of these clubmosses are poorly preserved and not well understood; the notable exception is the widespread Leclercqia complexa, which has been largely reconstructed…

The horticultural name for certain species of the genus Rubus in the plant order Rosales. In these species, the raspberry fruit, when ripe, separates thimblelike from the receptacle (unlike the blackberry). Raspberry plants are upright shrubs with…

The product of rice fermented with red yeast. Red yeast rice, produced by fermentation of red yeast (the filamentous fungus Monascus) on rice grains, has been used traditionally in Asian countries as a food colorant (due to the presence of various…

An annual cereal grass plant (Oryza sativa) cultivated for its carbohydrate-rich grain. Rice is the major source of food for nearly one-half of the world's population. Asian rice (Oryza sativa, family Poaceae, order Poales), simply referred to as…

Hevea brasiliensis, a member of the spurge family (Euphorbiaceae) and a native of the Amazon valley. It is the natural source of commercial rubber. The rubber tree (see illustration) can reach 60–100 ft (18–30 m) in height, with a circumference of…

A herb of the mint family in the genus Satureja. There are more than 100 species, but only S. hortensis (summer savory) and S. montana (winter savory) are grown for flavoring purposes. A number of varieties of each species are available, although no…

A fertilized ovule containing an embryo that forms a new plant upon germination. Seeds (Fig. 1) are small plant embryos encapsulated in a protective coat. The bearing of seeds characterizes the higher plants—the gymnosperms (conifers and allies) and…

The emergence of a new plant from a seed. Seed germination is the beginning or the process of development of a seed (a fertilized ovule containing an embryo, which forms a new plant upon germination). Hydration of a seed, which is called imbibition…

An extremely large tree, Sequoiadendron giganteum. The sequoia or giant sequoia (Sequoiadendron giganteum; formerly, Sequoia gigantea) [see illustration] is the only extant species of the genus Sequoiadendron (subfamily Sequoioideae, family…

Any difference, morphological or behavioral, between males and females of the same species. Sexual dimorphism is a condition in which there are differences in size, appearance, and behavior between males and females of the same species. This…

An order of flowering plants, division Magnoliophyta, in the euasterid I group of the asterid eudicotyledons. The order consists of two large and three small families, of approximately 4275 species. Solanaceae and Convolvulaceae account for all but…

A genus of extinct calcareous red algae (Rhodophyta). The extinct algal members of the genus Solenopora (family Solenoporaceae, order Corallinales, division Rhodophyta) are characterized by encrusting, rounded, nodular growth forms ranging in size…

Any of a variety of widely cultivated grasses, especially Sorghum bicolor, grown for grain and herbage. Sorghum (Fig. 1) includes many widely grown grasses having a variety of names. Sorghum is known as guinea corn in West Africa, kafir corn in…

A deciduous tree, Oxydendrum arboreum, of the heath family, indigenous to the southeastern section of the United States, and found from Pennsylvania to Florida and west to Indiana and Louisiana. Sourwood is hardy and is often cultivated in the…

An erect annual legume, Glycine max, known for its high protein and oil contents. Soybean (Glycine max, order Fabales) is one of the most significant commercial legume species. Native to China, soybean is widely cultivated for forage and for its…

An order of liverworts in the subclass Marchantiidae, consisting of two families, the terrestrial Sphaerocarpaceae (Sphaerocarpos and Geothallus) and the aquatic Riellaceae (Riella). The plants are characterized by envelopes surrounding each…

A class of the plant division Bryophyta containing plants commonly called peatmosses. The spongelike plants (Fig. 1) grow as perennials in soft cushions or lawns in wet habitats (rarely they grow submerged). The class consists of a single genus,…

One of the major divisions (formerly known as Equisetophyta) of vascular plants that includes both living and fossil representatives. The three principal orders are Pseudoborniales (Devonian), Sphenophyllales (Devonian-Triassic), and Equisetales…

An evergreen tree belonging to the genus Picea of the pine family. Spruce needles are single, usually four-sided, and borne on little peglike projections; the cones are pendulous. Resin ducts in the wood may be seen with a magnifying lens, but they…

The common name for edible fruits of several species of the genus Cucurbita: C. pepo, C. moschata, C. maxima, and C. mixta (also known as C. argyrosperma). The various species of squash originated in the Americas, but they are now grown in most…