Oak

Oak, any tree or shrub of the genus Quercus of the family Fagaceae (beech family). This complex genus includes as many as 600, found chiefly in north temperate zones and also in Polynesia. The more southerly species, ranging into the tropics, are usually evergreen. Oaks are cultivated for ornament and are prized as the major source of hardwood lumber. The wood is durable, tough, and attractively grained; it is especially valued in shipbuilding and construction and for flooring, furniture, railroad ties, barrels, tool handles, and veneer (particularly highly burled oak). The oaks are commonly divided into two groups, the black (or red) and the white. The former (e.g., the scarlet, pin, Spanish, willow, laurel, and shingle oaks) are characterized by leaves with sharp-tipped lobes and by acorns that mature in two years. The white oaks (e.g., the white, post, bur, cork, and holly oaks) are characterized by smooth-lobed leaves and acorns that mature in one year. Q. alba, the white oak, is the most important timber tree of the oak genus. Lumber-yielding species of chestnut (genus Castanea) are included in the white oak group when the term is used as a timber classification. The live oaks, evergreen species common in the S and SW United States, are sometimes considered a separate group. The bark of some oaks has been employed in medicine, in tanning, and for dyes; that of the cork oak supplies the cork of commerce. The galls caused by certain insects are utilized commercially. The Mediterranean kermes oak (Q. coccifera) is host to the kermes insect, source of the world's oldest dyestuff. Acorns, the fruit of oak trees, have long been employed as a source of hog feed, tannin (chiefly from valonia, the acorn cup of the Turkish oak, Q. aegilops), oil, and especially food. Acorns were one of the most important foods of the North American forest Native Americans; they were pulverized, leached to extract the bitter taste, and then cooked in various ways. Acorns have also been used as food in other regions where they are native. A symbol of strength, the oak has been revered for both historical and mythological associations. It was the favorite of Jove and Thor and especially sacred to the druids. St. Louis administered justice under an oak, and the Charter Oak is legendary in America. Several unrelated plants are also called oak, e.g., the Jerusalem oak (a lobe-leaved annual of the goosefoot family) and the poison oak of the sumac family (see poison ivy). Oaks are classified in the division Magnoliophyta, class Magnoliopsida, order Fagales, family Fagaceae.

Celery

Celery, biennial plant (Apium graveolens) of the family Umbelliferae (parsley family), of wide distribution in the wild state throughout the north temperate Old World and much cultivated also in America. It was first cultivated as a medicinal, then (during the Middle Ages) as a flavoring, and finally as a food, chiefly for soups and salads. The seeds are still used for seasoning. Celeriac is a variety cultivated chiefly in N Europe for the large edible turniplike root. Celery is classified in the division Magnoliophyta, class Magnoliopsida, order Umbellales, family Umbelliferae.

Parsnip

Parsnip, garden plant (Pastinaca sativa) of the family Umbelliferae (parsley family), native to the Old World. It has been cultivated since Roman times for its long, fleshy, edible root. Wine and beer have also been made from it. The wild form has become naturalized in North America, often proving a noxious weed. Parsnip is a biennial but is cultivated as an annual. The root can be left in the ground all winter without deterioration. It is also used as livestock feed. Parsnip is classified in the division Magnoliophyta, class Magnoliopsida, order Apiales, family Umbelliferae.

Carrot

Carrot, common name for some members of the Umbelliferae, a family (also called the parsley family) of chiefly biennial or perennial herbs of north temperate regions. Most are characterized by aromatic foliage, a dry fruit that splits when mature, and an umbellate inflorescence (a type of flattened flower cluster in which the stems of the small florets arise from the same point, like an umbrella). The seeds or leaves of many of these herbs have been used for centuries for seasoning or as greens (e.g., angelica, anise, caraway, chervil, coriander, cumin, dill, fennel, lovage, and parsley). The carrot, celery, and parsnip are vegetables of commercial importance. The common garden carrot (Daucus carota sativa) is a root crop, probably derived from some variety of the wild carrot (or Queen Anne's lace). In antiquity several types of carrot were grown as medicinals, and in Europe carrots have long been grown for use in soups and stews. The custom of eating carrots raw as a salad has become widespread in the 20th cent. Carrots are a rich source of carotene (vitamin A), especially when they are cooked. Several types of carrot have also been cultivated since ancient times as aromatic plants. Some are still planted as fragrant garden ornamentals, such as the button snakeroot and sweet cicely. A few members of the Umbelliferae produce lethal poison; it was one of these, the poison hemlock, that Socrates was compelled to take. The water hemlock is also poisonous. Carrots are classified in the division Magnoliophyta, class Magnoliopsida, order Umbellales, family Umbelliferae.

Watercress

Watercress, hardy perennial European herb (Nasturtium officinale) of the family Cruciferae (mustard family), widely naturalized in North America, found in or around water. Often cultivated commercially for the small, pungent leaflets, it is used as a peppery salad green or garnish. Other plants of the genus are sometimes called watercress and are used similarly. Watercress was formerly used as a domestic remedy and against scurvy. The ornamental plant whose common name is nasturtium is unrelated. Watercress is classified in the division Magnoliophyta, class Magnoliopsida, order Capparales, family Cruciferae.

Radish

Radish, herbaceous plant (Raphanus sativus) belonging to the family Cruciferae (mustard family), with an edible, pungent root sliced in salads or used as a relish. It is thought to be native to China; it spread to the Mediterranean area before Greek times and to the New World in the early 16th cent. There are many varieties, with white, red, or black roots of different shapes and sizes, some quite large. Radishes grow easily and quickly throughout temperate regions; they are a staple food in Japan and China, where they are generally pickled in brine. Radishes are classified in the division Magnoliophyta, class Magnoliopsida, order Capparales, family Cruciferae.

Turnip

Turnip, garden vegetable of the same genus of the family Cruciferae (mustard family) as the cabbage; native to Europe, where it has been long cultivated. The two principal kinds are the white (Brassica rapa) and the yellow (B. napobrassica), which is known as the rutabaga, the Swedish turnip, or the swede. The rutabaga is grown extensively only in Europe, where it is believed to have originated during the Middle Ages as a cross between the white turnip and the cabbage. The turnip is one of the root crops used as a stock feed as well as for human food. The green leaves (greens) are often cooked like spinach. The turnip is a biennial cool-weather crop, grown mostly in cool climates. The worst turnip pests are the root maggot and the flea beetle; it is also attacked by clubroot fungus. Turnips are classified in the division Magnoliophyta, class Magnoliopsida, order Capparales, family Cruciferae.