In its narrow, everyday use, vegetable is a word indicating any herb that is cultivated specially for table use in whole or part, such as the turnip (root), cabbage (leaves), broccoli (flowers), peas and beans (fruit). In its widest sense it includes all living things that are not animals - trees, shrubs, herbs, ferns, mosses, seaweeds, fungi, and the microscopic diatoms.
The unit of structure, the cell, is essentially the same in both animals and plants, but the combination of the cells into tissues and organs shows marked differences.
All animals depend for their food upon material originally elaborated by plants. The green plants alone have the power to construct this basic food material from elemental substances, and physiological processes different from those of animal assimilation are rendered necessary. The fungi approach the animals in this respect: they must feed upon material that has already done service as part of the structure of other plants or of animals.
The fine divisions of roots explore the soil in search of water in which are dissolved the salts of sodium, iron, potassium, phosphorus, calcium, sulphur, etc. The hairs with which the rootlets are clothed absorb this fluid by osmosis, and it is passed upward through the long vessels of the wood bundles until it reaches the cells of the leaf. These cells contain green bodies (chloroplasts) in their protoplasm, and it is these that impart the green colour to leaves and soft shoots. In the leaf-skin (epidermis) there are innumerable pores or stomata through which surplus water from the roots is evaporated and through which atmospheric air is admitted to the spaces between the leaf-cells.
The chloroplasts in these cells have the power to utilise solar energy in decomposing the carbon dioxide of the air, and the cells retain the carbon, setting free the oxygen. Water from the roots is broken up also into its elements, hydrogen and oxygen, and with these plus carbonstarch is formed. This, converted into grape sugar, is passed from cell to cell to parts of the plant whore it is needed for the production of new cells, wood, bark, leaves, or fruit. Starch is the material from which are made all the organic substances produced by the plant.
The surplus over present requirements is stored up as reserves in seeds, enlarged roots or stems, bulbs, or tubers for renewed growth or floral display at a later season. Waste products are converted into resins, oils/wax, or alkaloids - many of these being of considerable economic value to man. Part of the water stream from the roots passes by osmosis from cell to cell, where it is necessary in order to keep the protoplasm in an active condition; any insufficiency is followed by a flagging of the tissues, the drooping of leaves and young shoots. In addition to the absorption of carbon by the protoplasts for building purposes, the leaf-cells also take up oxygen from the atmosphere and give off carbon much as animals do.
As the plant respires without lungs and assimilates without digestive organs, so also it can effect movements without a muscular system and react to external stimuli without a nervous system. It is sensitive to light and heat; many plants have distinct night and day positions for their leaves. It responds positively and negatively to the force of gravity, the root going down into the earth and the stem rising into the air. The growing tip of a stem or shoot commonly nutates, i.e. moves from side to side or in a circle or ellipse. The plant can orientate itself, i.e. take up a definite position in regard to the incidence of light or other external stimulus. These movements appear to be controlled largely by alterations in the position of the mobile chloroplasts.
The reproductive process is, in essentials, similar to that of animals, the ovules or seed-eggs in the ovary requiring to be fertilised by male sperms represented by the pollen grains produced in the anthers. The result of such fertilisation is to cause the ovule to develop into an embryo capable of further development under suitable conditions into a plant resembling the parent. Research Vegetable
The allantois is a structure appearing during the early development of vertebrate animals - Reptiles, Birds, and Mammalia. It is largely made up of blood-vessels, and, especially in birds, attains a large size. It forms the inner lining to the shell, and may thus be viewed as the surface by means of which the respiration of the embryo is carried on. In Mammalia the allantois is not so largely developed as in birds, and it enters largely into the formation of the placenta. Research Allantois
Coconut (formerly Cocoa-nut, or coco-nut), IS a woody fruit of an oval shape, from 7 or 10 to 15 or 20 cm in length, covered with a fibrous husk, and lined internally with a white, firm, and fleshy kernel. The tree (Cocos nucifera) which produces the coconut is a palm, from 12 to 18 metres high. The trunk is straight and naked, and surmounted by a crown of feather-like leaves. The nuts hang from the summit of the tree in clusters of a dozen or more together. The external rind of the nuts has a smooth surface. This encloses an extremely fibrous substance, of considerable thickness, which immediately surrounds the nut. The latter has a thick and hard shell, with three black scars at one end, through one of which the embryo of the future tree pushes its way. This scar may be pierced with a pin; the others are as hard as the rest of the shell. The kernel encloses a considerable quantity of sweet and watery liquid, of a whitish colour, which has the name of milk.
This palm is a native of Africa, the East and West Indies, and South America, and is now grown almost everywhere in tropical countries. Food, clothing, and the means of shelter and protection are all afforded by the coconut tree. The kernels are used as food in various modes of dressing, and yield on pressure an oil which is largely imported into various countries. When dried before the oil is expressed they are known as copra. The fibrous coat of the nut is made into the well-known coconut matting; the coarse yarn obtained from it is called coir, which is also used for cordage. The hard shell of the nut is polished and made into a cup or other domestic utensil. The fronds are wrought into baskets, brooms, mats, sacks, and many other useful articles; the trunks are made into boats or furnish timber for the construction of houses.
By boring the tree a white sweetish liquor called toddy exudes from the wound, and yields by distillation one of the varieties of the spirit called arack. A kind of sugar called jaggery is also obtained from the juice by inspissation. Research Coconut
The date, is the fruit of the date palm or the tree itself, the Phoenix dactylifera. The
fruit is used extensively as an article of food by the natives of Northern Africa and of some countries of Asia. It consists of an external pericarp, separable into three portions and covering a seed which is hard and horny in consequence of the nature of the albumen in which the embryo plant is buried.
Next to the coconut tree the date is unquestionably the most interesting and useful of the palm tribe. Its stem shoots up to the height of 50 or 60 feet without branch or division, and of nearly the same thickness throughout its length. From the summit it throws out a magnificent crown of large feather-shaped leaves, and a number of spadices, each of which in the female plant bears a bunch of from 180 to 200 dates, each bunch weighing from 9 to 11 kgs. The fruit is eaten fresh or dried. Cakes of dates pounded and kneaded together are the food of the nomad Arabs who traverse the deserts. A liquor resembling wine is made from dates by fermentation. The Middle East, and the north of Africa are best adapted for the culture of the date-tree, and its fruit in these countries is an important article of food.
Dicotyledon is one of the two groups of flowering plants, primarily distinguished from the Monocotyledons by the two cotyledons or seed leaves formed at the end of the growing embryo, and by the depression between which the growing point of the shoot originates. Research Dicotyledon
Endogenous Plants are one of the large primary classes into which the vegetable kingdom is divided. It is so named in consequence of the new woody bundles being developed in the interior of the stem, in which there is no distinction of pith and bark. In transverse section these bundles appear scattered through the cellular matter, being more compact towards the circumference. The other organs of the plants are also characteristic. The leaves are generally parallel-veined, the flowers usually with three organs in each whorl, the seed has an embryo with one cotyledon, and the radicle issues from a sheath and is never developed into a tap-root in germination. To this class belong palms, grasses, rushes, lilies, etc. Endogens increase in thickness only to a limited extent; hence they are not injured by twining plants as exogens are. Research Endogen
In botany, endorhiza is a term describing the radicle of the embryo of monocotyledonous plants, which is developed inside a sheath from which it issues in germination. Research Endorhiza
The Ferns (Filices) are a natural order of cryptogamous or flowerless plants, forming the highest group of the acrogena or summit-growers. They are leafy plants, the leaves, or more properly fronds, arising from a rhizome or root-stock, or from a hollow arborescent trunk, and being circinate in vernation, a term descriptive of the manner in which the fronds are rolled up before they are developed in spring, having then the appearance of a bishop's crosier. On the veins of their lower surface, or their margins, the fronds bear small vessels named sporangia, containing spores. These spore-cases are arrangod in clusters, named sori, which are either naked or covered with a layer of the epidermis, which forms an involucre or indusium. When the spores germinate they produce a cellular structure of a leafy description, called the pro-embryo, or prothallus, upon which are developed organs which have received the names of antheridia and archegonia. When produced upon the prothallus these organs do not immediately give origin to a germinating spore, but from their mutual action proceeds a distinct cellular body, destined at a later period to develop into a fruit-bearing frond.
Ferns have a wide geographical range, but are most abundant in humid, temperate, and tropical regions. In the tropical forests the tree-ferns rival the palms, rising sometimes to a height of 15 or 18 metres. Ferns are very abundant as fossil plants. The earliest-known forms occur in Devonian rocks. Various systems of classification for ferns have been proposed over time. The order is usually divided into six or eight suborders or tribes distinguished by differences in the structure of the sporangium. The generic characters are founded on the position and direction of the sori and on the venation. The largest division is that of the Polypodiaceae, to which nearly all British ferns belong, such as the polypody, the lady-fern, the bracken, the hard-fern, the spleenwort, the maiden-hair, the hart's-tonguefern, etc. The royal fern, however, belongs to the Osmundaceae. A few of the ferns are used medicinally, mostly as demulcents and astringents. Some yield food. Pteris esculenta is the edible bracken of New Zealand. Research Ferns
The Probert Encyclopaedia was designed, edited and programed by
Matt and Leela Probert
Abbreviations
Research Vegetable
