calendula, (genus Calendula), small genus of 15–20 species of herbaceous plants (family Asteraceae) found in temperate regions of Eurasia and North Africa.

Physical description

Calendulas are annual or perennial plants with waxy, smooth, or glandular stems. The simple leaves can be somewhat toothed and are borne alternately along the stems. The leaves of some species are sessile (lacking a leaf stalk) and may have clasping leaf bases. The composite flower heads, borne singly, consist of yellow or orange ray flowers and central disk flowers that can be yellow, red, or purple in colour. The fruit is a curved achene.

Major species and uses

The pot marigold (Calendula officinalis) is grown especially for ornamental purposes and is commonly found in herbal products and cosmetics. The petal-like ray flowers are edible and are sometimes used in salads. Field marigold (C. arvensis) is native to Europe and is used similarly. Sea marigold, or trailing calendula (C. maritima), of western Sicily is a critically endangered species.

Venus's-flytrap. Venus's-flytrap (Dionaea muscipula) one of the best known of the meat-eating plants. Carnivorous plant, Venus flytrap, Venus fly trap
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herbal, ancient manual facilitating the identification of plants for medicinal purposes. Hundreds of medicinal plants were known in India before the Christian era, and the Chinese have a compilation, still authoritative, of 1,892 ancient herbal remedies. The Greeks had written accounts, and, according to the elder Pliny, the physician Crateuas (early 1st century bc) produced a herbal with coloured illustrations. This has not survived but was probably largely embodied in the De materia medica of the Greek physician Pedacius Dioscorides. A Byzantine version of his famous herbal is the Constantinopolitan, or Viennese, Codex (c. ad 512). Some of its illustrations are probably derived from Crateuas, together with plant names, such as Anemone and Anagallis, which are still in use. Many manuscript herbals, drawing largely from Dioscorides and Pliny, were published in medieval Europe; during the 15th century several were printed, a notable one being Konrad von Megenberg’s Das puch der natur (or Buch der natur, “Book of Nature”). When printed in 1475, it included the first known woodcuts for botanical illustrations. Very few original drawings were prepared for herbals before the 16th century: illustrations were copies and copies of copies. They became highly stylized, not only ceasing to resemble the plants depicted but also incorporating mythological notions. “Narcissus,” for example, in Jacob Meidenbach’s Hortus sanitatis (1491), is unidentifiable: a human figure, instead of the plant’s sex organs, emerges from each perianth (sepals and petals of a flower).

Otto Brunfels’ Herbarium vivae eicones (1530s) contains excellent and accurate drawings by the wood engraver Hans Weiditz. This emphasis on accuracy also appeared in the subsequent herbals of Hieronymus Bock and Leonhard Fuchs. Plants brought back by explorers then began to be illustrated. Nicolás Monardes’ Dos libros (1569), for example, contains the first published illustration of tobacco. A latinized version of an Aztec herbal (1552) contains formalized illustrations resembling European ones, suggesting that the artists were following the traditions of their Spanish masters rather than an indigenous style of drawing. Among other well-known herbalists of those times were John Gerard, Conrad Gesner, and Gaspard Bauhin.

Alongside the genuine herbals other works of a superstitious nature probably existed. Many were concerned with the fanciful medical theory of the doctrine of signatures, the use of plants to cure human ailments on the basis of supposed anatomical resemblances. In England these culminated in Nicholas Culpeper’s A Physicall Directory (1649), which was a pseudoscientific pharmacopoeia. The herbals were replaced in the 17th-century by floras, books in which plants were studied for their own sake.

biology; microscope
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