Kids Research Express

Stonewort, common name for about 200 species of algae belonging to the phylum Charophyta of the plant kingdom. Stoneworts are so called because the plant surface is usually covered by a thick, brittle, limy crust of calcium carbonate. They are closely related to green algae and have sometimes been regarded as a class (Charophyceae) within that phylum. Stoneworts grow submerged in hard (alkaline) water and often form dense mats on the bottom of ponds and brackish waters. They are much larger than typical green algae and superficially resemble higher plants in their rootlike rhizoids, leaflike branches at regular intervals, and upright cylindrical axes surrounded by a sheath of cells. Asexual reproduction usually involves the shedding of reproductive branches. Sexual reproduction is by the formation, at leaf nodes, of a large egg in a female sexual structure called an oogonium, and of sperm in filaments constituting the male sexual organ, or antheridium.

Deciduous Plants, plants that shed their leaves annually at the approach of a season of cold or drought. The term is also applied to plants that drop leaves, fruits, or flowers at maturity, in contrast to those that retain their foliage or flowers. Plants that keep their foliage throughout the year are called evergreens .

Evergreen, name applied to any plant that retains its foliage through two or more consecutive seasons. In contrast to deciduous plants , which shed their leaves seasonally, evergreens retain their foliage anywhere from 1 to 18 years. Many common varieties, such as spruce , fir , and other members of the pine family, have needle-shaped foliage, but most evergreens are broad-leaved. Some shrubs and trees are both deciduous and evergreen, depending on where they are grown. Many species are valuable for their timber, while mistletoe and other evergreen foliage is popular as Christmas decoration.

Grasses, common name for a large family of flowering plants that is economically and ecologically the most important in the world. The grass family contains about 635 genera and 9000 species, making it the fourth largest family after the legume, orchid, and composite families (see Composite Flowers ). IMPORTANCE All the world’s cereal crops are grasses, and thus the grass family is economically very important. The world’s 5 top crops produce more tonnage than the next 25 combined, and 4 of the top 5 are the cereals rice , wheat , corn , and barley . Human well-being depends on these few grasses, so even small crop failures of any one of them can produce widespread hunger and economic disruption. In addition, the family provides most of the world’s sugar (see Sugarcane ). Another member of the family, bamboo , is an important construction material as well as a food source; it also has been used in papermaking. Citronella, used both in perfumery and as an insect repellent, is an oil ...

Halophyte, term for salt-resistant plants, coined by the U.S. geologist Oscar E. Meinzer (1876-1948). Found in salt marshes and mangrove swamps, many halophytes could thrive in well-watered lands except for their inability to compete with the other plants found there. Generally fleshy and with gray-green foliage, many halophytes deal with the salt in their environment by eliminating it through special salt-secreting glands in their leaves. Others store the salt in leaves and stems that are shed at the end of the growing season, while the remaining halophytes keep salt from entering their cells by means of semipermeable membranes in their roots. One typical genus is that of the saltbush, Atriplex.

Spices, aromatic flavorings made from parts of plants. The term spice is usually applied to pungent plant products, especially plants native to tropical Asia and the Moluccas, or Spice Islands, of Indonesia. It frequently also includes herbs, which are the fragrant leaves of herbaceous plants, many of which are native to temperate regions. With few exceptions, the spices and herbs known today were being used early in human history. Spice trade with the Orient was flourishing well before the advent of Christianity. The discovery of many spices probably predates the earliest civilizations, when primitive humans were attracted to the aromatic effects produced by what are now called essential oils, which are found in various plant parts. Interestingly, many of the same oils that attracted humans evolved in nature as toxins or repellents against animals; the leaves of the mint plant and the bark of the cinnamon tree, for example, evolved as protection against grass-eating ungulates and bark...

The great variety of herb and spice flavors are produced from nearly all parts of plants, from the leaves to the roots. Among those producing fragrant leaves are basil , rosemary , sage , savory, tarragon , and thyme, all of which are small annual or perennial plants. Bayleaf, or sweet laurel , used to flavor meats, sauces, and vinegars, comes from a shrub or tree. Among the many spices derived from the ripe fruit or seeds of plants are aniseed (see Anise ), caraway seed, chili peppers, coriander seed, dillseed (see Dill ), fennel seed, juniper berry, mustard seed, nutmeg, pepper, poppy seed, and sesame seed. Licorice-flavored aniseed, which comes from Pimpinella anisum, a member of the carrot family, is used whole for baking and as an essential oil in candies and the liquors absinthe and anisette. Juniper berry, used to flavor gin, comes from the low evergreen shrub Juniperus communis. The strongest mustard seed comes from black mustard, Brassica nigra, which was probably the ...

Basil, common name for any of a genus of plants of the mint family. Basil is a sweet herb used for fragrance and as a seasoning for food. Sweet basil is an annual plant, a native of warm climates, about 30 cm (about 12 in) high, with ovate stalked leaves, and has long been cultivated in Europe. Bush basil is a small cultivated form. Basil, or mountain mint, is also a common name for plants of a separate, North American genus of the mint family. Scientific classification: Basil belongs to the family Lamiaceae (formerly Labiatae). Sweet basil is classified as Ocimum basilicum and bush basil as Ocimum minimum. Mountain mints are classified in the genus Pycnanthemum.

Wild Bergamot, a culinary herb , member of the mint family, named for the Italian bergamot orange, which has a similar scent. It is also called bee balm, because it attracts bees, and Oswego tea, because Native Americans of the Oswego tribe used it to make a medicinal tea. It was introduced into cultivation by American botanist John Bertram in 1744, who found it growing on the shores of Lake Ontario in the United States. It was widely used for brewing tea during the boycott of British tea that followed the Boston Tea Party of 1773. Wild bergamot is native to eastern North America from New York to Michigan and south to Georgia and Tennessee. It survives winter temperatures as low as -34° C (-30° F). It is best adapted to moist soils in full sun to partial shade. Wild bergamot is a herbaceous perennial, a plant with soft, green stems that lives for more than two growing seasons. The aboveground portions die each year after the first freeze, but the plant regrows from the roots each spri...

Borage, common name for a large, widely distributed family of flowering plants (see Mint ), and for its representative genus. The family contains about 154 genera and 2500 species, found throughout the temperate and subtropical regions of the world but centered in the Mediterranean area. Plants vary widely in habit from annuals to perennials and from herbs to shrubs to trees. They usually have rough hairs on the stems and leaves. The inflorescence (flower cluster) is characteristic of the family. It is spirally coiled and unrolls and straightens from the base as the flowers open. The insect-pollinated flowers are regular (radially symmetrical) with five-lobed corollas (fused petals) that are funnel-shaped or bell-shaped. The ovary is deeply lobed and matures into a fruit consisting of four nutlets. In addition to horticultural subjects, the family provides timber, dyes, and medicinal plants. One species of borage, native to Europe and North Africa, has been used as a culinary herb sinc...

Caraway, common name for a plant that has long been cultivated in temperate zones for its aromatic fruit, called caraway seeds. These seeds are used in cookery, confectionery, and medicine. The caraway plant is a biennial herb ; it grows up to 61 cm (up to 2 ft) high and has finely divided leaves and clusters of white flowers. The large oil glands of the seed contain caraway oil, which is used to flavor the liqueur aquavit. This oil is also used in perfumery and in pharmacy as an aromatic stimulant and as a flavoring agent. Scientific classification: The caraway plant belongs to the family Apiaceae (formerly Umbelliferae). It is classified as Carum carvi.

Wild Chamomile, a culinary herb with daisylike flowers that are dried and brewed as a soothing tea reputed to aid indigestion, calm muscle spasms, and relieve the pain and swelling of arthritis. A member of the composite flower family, it is also called sweet false chamomile and German chamomile, to distinguish it from the closely related true or Roman chamomile. Wild chamomile is native to the temperate regions of Europe and western Asia. It has become naturalized in North America, where it grows wild. It grows best in poor, sandy soil in full sun. Wild chamomile is an annual, a plant that lives only one growing season. It reaches about 60 to 75 cm (about 2 to 2.5 ft) in height and has an upright, branching main stem. The bright green leaves, about 5.5 cm (about 2.2 in) long, are strongly apple-scented and finely divided, resembling fern leaves. The flowerhead is about 2.5 cm (about 1 in) in diameter. The yellow center of the flowerhead, which consists of disk flowers, is hollow a...

Chervil, common name for an aromatic annual herb of the parsley family. The species, native to Europe, reaches a height of about 61 cm (about 24 in) and bears small, deeply cut leaves. The plant is cultivated for the leaves, which are used as a potherb, seasoning, and garnish in the same way as parsley. Scientific classification: Chervil belongs to the family Apiaceae (formerly Umbelliferae). It is classified as Anthriscus cerefolium .

Cicely, also myrrh, anise fern, and sweet chervil, common name for an herb with leaves that smell strongly of anise or licorice, member of the carrot family. The name cicely is also used for a related genus of herbaceous perennials (plants that live at least three years and have nonwoody stems) with fleshy roots, tiny white or yellow flowers, and cylindrical fruit. Both the herb and the genus are also called sweet cicely. A native of Europe, cicely reaches about 1 m (about 3 ft) in height and has pale green, anise-scented, fernlike leaves that consist of three lance-shaped leaflets. The small, whitish flowers form umbrella-shaped clusters in early spring and late summer. The shiny, ribbed fruit is about 2.5 cm (about 1 in) long and grows in upright clusters. The cicely herb grows best in moist, shady sites and survives winter temperatures as low as -40° C (-40° F). It does not grow well in tropical or subtropical regions. The leaves, stems, and seed pods can be used to add an anise fl...

Coriander, common name for an annual herb of the parsley family that grows to a height of about 30 to 90 cm (about 12 to 36 in). The lower leaves are divided into fine, threadlike partitions; the white and pink flowers grow in small, loose clusters. Native to Europe and Asia Minor, coriander has become naturalized in the United States. It is cultivated for its fruit, the dried seeds of which, also called coriander, are used as a spice in a wide variety of foods, and for its pungent leaves, called cilantro, a basic ingredient in Latin American and Asian cooking. Oil that is extracted from the seed is used in the preparation of liqueurs and is a medicine for abdominal discomfort.

Cress, common name for a number of herbs, most of which are used as garnishings or in salads for their pungent flavor and high vitamin C content. One of the most common cresses is watercress, a perennial that grows in brooks and springs or in wet ground. Garden cress, also called peppergrass, is an Asian annual sometimes cultivated in the United States. A similar native species is wild peppergrass, a common weed. The various species known as bitter cress include the cuckooflower, found in bogs and other wet areas in the northern United States. Indian cress is known as nasturtium, although it is not related to the garden nasturtium. Scientific classification: Cresses belong to the family Brassicaceae (formerly Cruciferae). Watercress is classified as Nasturtium officinale, garden cress as Lepidium sativum, wild peppergrass as Lepidium virginicum, and the cuckooflower as Cardamine pratensis.

Dill, common name for an annual or biennial herb of the parsley family. It grows wild in grainfields of southern Europe, the British Isles, and the United States and is also cultivated as an herb. Dill has a strong, aromatic taste; its leaves are used for flavoring pickles and sauces. Scientific classification: Dill belongs to the family Apiaceae (formerly Umbelliferae). It is classified as Anethum graveolens.

Lemon Balm, also bee herb or sweet balm, a culinary and medicinal herb , member of the mint family. Lemon balm is native to southern Europe and northern Africa, and east as far as the Caucasus and northern Iran. The lemon-scented leaves add flavor to jellies, liqueurs, fruit salads, and cold drinks. The dried leaves make a tea that reportedly soothes cold symptoms, fevers, and headaches. The strongly scented leaves are also used in perfumes and natural cosmetics, and their juice takes the sting out of insect bites. Fruit growers sometimes plant lemon balm in orchards to attract bees to pollinate their crops. It grows best in infertile, moist soils in slightly shady areas, but will tolerate drought, full sun, and moderate shade. Plants can survive winter temperatures as low as -34°C (-30°F), but grow poorly in semitropical and tropical regions. Lemon balm is a perennial herb—that is, one that lives at least three years. It is bushy and upright, reaching a height of about 1 m (about 3 ft...

Marjoram, common name for any of a genus of perennial herbs of the mint family. The herbs, native to Eurasia, are cultivated in the United States for the highly aromatic young leaves, which are used either fresh or dried as a seasoning. The flowers, which are borne in spikes, have a five-toothed calyx (outer floral envelope) and a two-lipped corolla (inner floral envelope). Either two or four stamens (male flower part) and a solitary pistil (female flower part) are present. The fruit is an achene (dry and one-seeded). The wild marjoram, more commonly called oregano, is a perennial; sweet marjoram is an annual, or frost-free, perennial. Scientific classification: Marjorams belong to the family Lamiaceae (formerly Labiatae). Wild marjoram is classified as Origanum vulgare. Sweet marjoram is classified as Origanum majorana.

Mint (plant), common name for a family of woody or herbaceous flowering plants of worldwide distribution, and for its well-known genus. Members of the mint family often contain aromatic oils, and many (often of Mediterranean origin) are cultivated as culinary herbs. These include marjoram and oregano, thyme , sage, rosemary , savory, and basil . The mint genus itself contains many well-known cultivated species: peppermint, spearmint, and pennyroyal. These and other members of the family, such as lavender and shellflower, are grown as ornamentals. The family belongs to an order comprising more than 10,000 species, which, although placed in 4 families, are contained primarily in the 3 largest: the mint family, with 5,600 species; the verbena family, with 1,900 species; and the borage family, with 2,500 species. The lennoa family contains only 6 species—fleshy root parasites that lack chlorophyll. The order characteristically has opposite, decussate leaves (pairs of leaves at righ...

Mustard, common name for a large family of pungent-juiced herbs, important for the many food plants and other crops it produces, and for its representative genus. The family contains about 390 genera and 3,000 species. It is cosmopolitan in distribution, with centers of diversity in the Mediterranean region and southwestern and Central Asia, where about two-thirds of the species occur. Most members of the mustard family are annual or perennial herbs; a few are shrubs or climbers. The flowers are characteristic and distinctive. Four petals are arranged opposite one another in the form of a cross. Six stamens are arranged in pairs. The filaments of the outer pair are short, whereas those of the two inner pairs are longer. The fruit is typically a capsule with two chambers divided by a false septum; at maturity, it splits in two from the bottom. Many variations on this basic fruit type are found in the family, and characteristics of the fruits are heavily used in distinguishing and cla...

Top, left to right: star-of-Bethlehem, belladonna , poison ivy , poison oak , bottom: yew , oleander, wisteria , and poison hemlock . Poisonous Plants, plants containing substances that, taken into the body of humans or animals in small or moderate amounts, provoke a harmful reaction resulting in illness or death. Possibly as many as one out of each 100 species of plants is poisonous, but not all have been recognized as such. Dangerous plants are widely distributed in woods (baneberry) and fields (star-of-Bethlehem), swamps (false hellebore) and dry ranges (scrub oak), roadsides (climbing bittersweet) and parks (kalmia), and may be wild (celandine) or cultivated (wisteria). Many ornamental plants, such as oleander, lily of the valley, and mistletoe, are poisonous. Botanists have no set rules to determine accurately whether any given plant is poisonous. Toxic species are scattered geographically, in habitat, and in botanical relationship. They contain more than 20 kinds of poisonous pri...

Parsley, common name for a large family of herbaceous flowering plants, containing many important foods and flavorings, and for one of its genera. This family of dicots contains about 3,000 species and is nearly cosmopolitan in distribution, although most common in temperate areas. The family is well known for its characteristic inflorescence (flower cluster), called an umbel. The individual pedicels (flower stalks) arise from the same point on the peduncle (one of the inflorescence stalks) and are of such lengths that all the flowers are raised to the same height above their point of common attachment; thus the umbel is flat-topped. The basically five-parted flowers are rather uniform throughout the family. The fruits, however, which develop from the two-parted ovary, which is inferior (borne below and fused to the other flower parts), vary remarkably. Members of the family have many uses. The carrot and parsnip are important root crops; celery is the petioles (leafstalks) of one ...