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See also:FRUIT (through the See also:French from the See also:Lat. fructus; frui, to enjoy) , in its widest sense, any product of the See also:soil that can be enjoyed by See also:man or animals; the word is so used constantly in the See also:Bible, and extended, as a Hebraism, to offspring or progeny of man and of animals, in such expressions as " the See also:fruit of the See also:body," " of the womb," " fruit of thy See also:cattle " (Deut. See also:xxviii . 4), &c., and generally to the product of any See also:action or effort . Between this wide and frequently figurative use of the word and its application in the strict botanical sense treated below, there is a popular meaning, regarding the See also:objects denoted by the word entirely from the standpoint of edibility, and differentiating them roughly from those other products of the soil, which, regarded similarly, are known a. s vegetables . In this sense " fruit " is applied to such See also:seed-envelopes of See also:plants as are edible, either raw or cooked, and are usually sweet, juicy or of a refreshing flavour . But applications of the word in this sense are See also:apt to be loose and shifting according to the See also:fashion of the See also:time . Fruit, in the botanical sense, is See also:developed from the See also:flower as the result of fertilization of the ovule . After fertilization various changes take See also:place in the parts of the flower . Those more immediately concerned in the See also:process, the anther and stigma, rapidly See also:wither and decay, while the filaments and See also:style often remain for some time; the floral envelopes become dry, the petals fall, and the sepals are either See also:deciduous, or remain persistent in an altered See also:form; the ovary becomes enlarged, forming the pericarp; and the ovules are developed as the seeds, containing the embryo-plant . The See also:term fruit is strictly applied to the mature See also:pistil or ovary, with the seeds in its interior; but it often includes other parts of the flower, such as the bracts and floral envelopes . Thus the fruit of the See also:hazel and See also:oak consists of the ovary enveloped by the bracts; that of the See also:apple and See also:pear, of the ovary and floral receptacle; and that of the pineapple, of-the whole inflorescence . Such fruits are sometimes distinguished as pseudocarps . In popular See also:language, the fruit includes all those parts which exhibit a striking See also:change as the result of fertilization . In See also:general, the fruit is not ripened unless fertilization has been effected; but cases occur as the result of cultivation in which the fruit swells and becomes to all See also:appearance perfect, while no seeds are produced . Thus, there are seedless oranges, grapes and pineapples . When the ovules are unfertilized, it is See also:common to find that the ovary withers and does not come to maturity; but in the See also:case of bananas, plantains and breadfruit, the non-development of seeds seems to'See also:lead to a larger growth and a greater succulence of fruit . The fruit, like the ovary, may be formed of a single carpel or of several . It may have one See also:cell or cavity, being unilocular; or many, multilocular, &c . The number and nature of the divisions depend on the number of carpels and the extent to which their edges are folded inwards . The appearances presented by the ovary do not always remain permanent in the fruit . See also:Great changes are observed to take place, not merely as regards the increased See also:size of the ovary, its softening or hardening, but also in its See also:internal structure, owing to the suppression, additional formation or enlargement of parts . Thus, in the ash (fig . I) an ovary with two cells, each containing an ovule attached to a central See also:placenta, is changed into a unilocular fruit with one seed; one ovule becomes abortive, while the other, g, gradually enlarging until the septum is pushed to one See also:side, unites with the walls of the cell, and the placenta appears to be parietal . In the oak and hazel, an ovary with three and two cells respectively, and two ovules in each, produces a one-celled fruit with one seed . In the coco-See also:nut, a trilocular and triovular ovary produces a one-celled, one-seeded fruit . This See also:abortion may depend on the pressure caused by the development of certain ovules, or it may proceed from non-fertilization of all the ovules and consequent non-enlargement of the carpels . Again, by the growth of the placenta, or the folding inwards of parts of the carpels, divisions occur in the fruit which did not exist in the ovary . In Calharlocarpus See also:Fistula a one-celled ovary is changed into a fruit having each of its seeds in a See also:separate cell, in consequence of See also:spurious dissepiments being produced See also:horizontal from the inner See also:wall of the ovary . In See also:flax (Linum) by the folding inwards of the back of the carpels a five-celled ovary becomes a ten-celled fruit . In Astragalus the folding inwards of the dorsal suture converts a one-celled ovary into a two-celled fruit; and in Oxytropis the folding of the ventral suture gives rise to a similar change . The development of cellular or pulpy See also:matter, and the enlargement of parts not forming whorls of the flower, frequently alter the appearance of the fruit, and render it difficult to discoverits formation . In the See also:gooseberry (fig . 29), See also:grape, See also:guava, See also:tomato and See also:pomegranate, the seeds nestle in pulp formed by the placentas . In the See also:orange the pulpy matter surrounding the seeds is formed by succulent cells, which are produced from the inner partitioned lining of the pericarp . In the See also:strawberry the receptacle becomes succulent, and bears the mature carpels on its See also:convex See also:surface (fig . 2) ; in the See also:rose there is a fleshy hollow receptacle which bears the carpels on its See also:concave surface (fig . 3) .
In the See also:juniper the scaly bracts grow up See also:round the seeds and become succulent, and in the fig (fig
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4) the receptacle becomes succulent and encloses an inflorescence
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The pericarp consists usually of three layers, the See also:external, or epicarp (fig
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5, ep); the See also:middle, or mesocarp, m; and the internal,
From Strasburger's Lehrbuch der Botanik, by permission of Gustav See also:Fischer
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From Strasburger's Lehrbuch der Bolanik, by permission of Gustav Fischer
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or endocarp, en
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These layers are well seen in such a fruit as the See also:peach, See also:plum or See also:cherry, where they are separable one from the other; in them the epicarp forms what is commonly called the skin; the mesocarp, much developed, forms the flesh or pulp, and hence has sometimes been called See also:sarcocarp; while the endocarp, hardened by the See also:production of woody cells, forms the See also: In the See also:melon the epicarp and endocarp are very thin, while the mesocarp forms the bulk of the fruit, differing in texture and See also:taste in its external and internal parts . The rind of the orange consists of epicarp and mesocarp, while the endocarp forms partitions in the interior, filled with pulpy cells . The See also:part of the pericarp attached to the peduncle is the See also:base, and the point where the style or stigma existed is the See also:apex . This latter is not always the apparent apex, as in the case of the ovary; it may be lateral or even basilar . The style sometimes remains in a hardened form, rendering the fruit apiculate; at other times it falls off, leaving only traces of its existence . The presence of the style or stigma serves to distinguish certain single-seeded pericarps from seeds . When the fruit is mature and the seeds are ripe, the carpels usually give way either at the ventral or dorsal suture or at both, Dehlsceoce and so allow the seeds to See also:escape . The fruit in this case of hYsce is dehiscent . But some fruits are indehiscent, falling to the ground entire, and the seeds eventually reaching the soil by their decay . By dehiscence the pericarp becomes divided into different pieces, or valves, the fruit being univalvular, bivalvular or multivalvular, &c., according as there are one, two or many valves . The splitting extends the whole length of the fruit, or is partial, the valves forming See also:teeth at the apex, as in the See also:order See also:Caryophyllaceae (fig . 6) . Sometimes the valves are detached only at certain points, and thus dehiscence takes place by pores at the apex, as in See also:poppy (fig . 7), or at the base, as in See also:Campanula . Indehiscent fruits are either dry, as the nut, or fleshy, as the cherry and apple . They are formed of one or several carpels . In the former case they usually contain only a single seed, radiating peltate stigma s . Dehiscent fruits, when com- posed of single carpels, may open by the ventral suture only, as in the See also:paeony, See also:hellebore, Aquilegia (fig . 28) and Caltha; by the dorsal suture only, as in magnolias and some Proteaceae, or by both together, as in the See also:pea (fig . 8) and See also:bean; in these cases the dehiscence is sutural . When composed of several From Vines' Students' See also:Text-See also:Book of See also:Botany, by per-See also:mission of See also:Swan Sonnenschein & Co . From Strasburger's Lehrbuch der Botanik, by permission of Gustav Fischer . From Strasburger's Lehrbuch der Botanik, by permission of Gustav Fischer . Saxifraga a splitting for a See also:short distance of the ventral sutures of the carpels takes place, so that a large apical See also:pore is formed . In the fruit of See also:Cruciferae, as wallflower (fig . 14), the valves separate from the base of the fruit, leaving a central replum, or See also:frame, which supports the false septum formed by a prolongation from the parietal placentas on opposite sides of the fruit, extending between the ventral sutures of the carpels . In Orchidaceae (fig . 15) the pericarp, when ripe, separates into three valves in a loculicidal manner, but the midribs of the carpels, to which the placentas are attached, often remain adherent to the See also:axis both at the apex and base after the valves bearing the seeds have fallen . The other type of dehiscence is transverse, or circumscissile, when the upper part of the See also:united carpels falls off in the form of a lid or operculum, as in Anagallis and in See also:henbane (Hyoscyamus) (fig . 16) . Sometimes the axis is prolonged beyond the base of the carpels, as in the See also:mallow and See also:castor-oil plant, the carpels being united to it throughout their length by their faces, and separating from it without opening . In the UmbelJiferae the two carpels separate from the See also:lower part of the axis, and remain attached by their apices to a prolongation of it, called a carpophore or podocarp, which splits into two (fig . 25) and suspends them; hence the fruit is termed a cremocarp, which divides into two mericarps . The general term schizocarp is applied to all dry fruits, which break up into two or more one-seeded indehiscent mericarps, as in Hedysarum (fig . 17) . In the order See also:Geraniaceae the styles remain attached to a central See also:column, and the mericarps separate from below upwards, before dehiscing by their ventral suture (fig . 18) . Carpels which separate one from another in this manner are called cocci . They are well seen in the order See also:Euphorbiaceae, where there are usually three such carpels, and the fruit is termed tricoccus . In many of them, as Hura crepitans, the cocci separate with great force and See also:elasticity . In many leguminous plants, such as Ornithopus, Hedysarum (fig . 17), See also:Entada, Coronitla and the See also:gum-arabic plant (See also:Acacia arabica), the fruit becomes a schizocarp by the formation of transverse partitions from the folding in of the sides of the pericarp, and distinct separations taking place at these partitions . Fruits are formed by one flower, or are the product of several See also:flowers combined . In the former case they are either apocarpous, of one mature carpel or of several separate See also:free carpels; or syncarpous, of several carpels, more or less completely united . When the fruit is composed of the ovaries of several flowers united, it is usual to find the bracts and floral envelopes also joined with them, so as to form one See also:mass; hence such fruits are known as multiple, confluent or anthocarpous . The term See also:simple is applied to fruits which are formed by the ovary of a single flower, whether they are composed of one or several carpels, and whether these carpels are separate or combined . The See also:object of the fruit in the See also:economy of the plant is the See also:protection and See also:nursing of the developing seed and the See also:dispersion of the ripe Dispersal seeds . Hence, generally, one-seeded fruits are indehiscent, of fruit or while fruits containing more than one seed open to allow seed. of the dispersal of the seeds over as wide an See also:area as possible . The form, colour, structure and method of dehiscence of fruits and the form of the contained seeds are intimately associated with the means of dispersal, which fall into several categories . (1) By a mechanism residing in the fruit . Thus many fruits open suddenly when they are dry, and the seeds are ejected by the twisting or curving of the valves, or in some other way; e.g. in gorse, by the See also:spiral curving of the valves; in See also:Impatiens, by the twisting of the cocci; in squirting See also:cucumber, by the pressure exerted on the pulpy contents by the walls of the pericarp . (2) By aid of various external agencies such as See also:water . Fruits or seeds are sometimes sufficiently buoyant to See also:float for a See also:long time on See also:sea-or fresh-water; e.g. coco-nut, by means of its thick, fibrous coat (mesocarp), is carried hundreds of See also:miles in the sea, the tough, leathery outer coat (epicarp) preventing it from becoming water-soaked . Fruits and seeds of See also:West See also:Indian plants are thrown up on the coasts of See also:north-west See also:Europe, having been carried by the Gulf Stream, and will often germinate; many are rendered buoyant by See also:air-containing cavities, and the embryo is protected from the sea-water by the tough coat of fruit or seed . Water-See also:lily seeds are surrounded with a spongy See also:tissue when set free from the fruit, and float for some distance before dropping to the bottom . (3) The most general See also:agent in the dispersal of seeds is the See also:wind or currents of air—the fruit or seed being rendered buoyant by wing-developments as in fruits of ash (fig . 1) or See also:maple (fig . 21), seeds of pines and firs, or many members of the order Bignoniaceae; or See also:hair-developments as in fruits of See also:clematis, where the style forms a feathery From Strasburger's Lehrbuch der Botanik, by permission of Gustav Fischer . appendage, fruits of many See also:Compositae (See also:dandelion, See also:thistle, &c.), which are crowned by a plumose pappus, or seeds of See also:willow and See also:poplar, or Asclepias (fig . 36), which See also:bear tufts of silky hairs; to this See also:category belong bladder-like fruits, such as bladder-senna, which are easily rolled by the wind, or cases like the so-called rose of See also:Jericho, a small cruciferous plant (Anastatica hierocuntica), where the plant dries up after developing its fruits and becomes detached from the ground; the branches curl inwards, and the whole plant is rolled over the dry ground by the wind . The wind also See also:aids the dispersal of the seeds in the case of fruits which open by small teeth (many Caryophyllaceae [fig . 6]) or pores (poppy [fig . 7], Campanula, &c.) ; the seeds are in these cases small and numerous, and are jerked through the pores when the capsules, which are generally See also:borne on long, dry stems or stalks, are shaken by the wind . (4) In other cases members of the See also:animal See also:world aid in seed-dispersal . Fruits often bear stiff hairs or small hooks, which cling to the coat of an animal or the feathers of a See also:bird; such are fruits of See also:cleavers (Galium Aparine), a common hedge-See also:row plant, See also:Ranunculus arvensis (fig . 20), See also:carrot, See also:Geum, &c.; or the fruit or seed has an often See also:bright-coloured, fleshy From Strasburger's Lehrbuch See also:des Botanik, by permission of Gustav Fischer . From Vines' Students' Text-Book of Botany, by permission of Swan Sonnenschein & Co . covering, which is sought by birds as See also:food, as in stone-fruits such as plum, cherry (fig . 5), &c., where the seed is protected from injury in the mouth or See also:stomach of the animal by the hard endocarp ; or the hips of the rose (fig . 3), where the succulent See also:scarlet " fruit (the swollen receptacle) envelops a number of small dry true fruits (achenes), which cling by means of stiff hairs to the See also:beak of the bird . Simple fruits have either a dry or succulent pericarp . The achene is a dry, one-seeded, indehiscent fruit, the pericarp of which is closely applied to the seed, but separable from it . It is solitary, Forms of forming a single fruit, as in the See also:dock (fig . 19) and in the fruit . cashew, where it is supported on a fleshy peduncle; or aggregate, as in Ranunculus (fig . 20), where several achenes are placed on a common elevated receptacle . In the strawberry the achenes (fig . 2) are aggregated on a convex succulent receptacle . In the rose they are supported on a concave receptacle (fig . 3), and in the fig the succulent receptacle completely encloses the achenes (fig . 4) . In Dorstenia the achenes are situated on a See also:flat or slightly concave receptacle . Hence what in common language are called the seeds of the strawberry, rose and fig, are in reality ripe carpels . The styles occasionally remain attached to the achenes in the form of feathery appendages, as in Clematis . In, Compositae, the fruit is an inferior achene (cypsela), to which the pappus (modified calyx) remains adherent . Such is also the nature of the fruit in Dipsacaceae (e.g. scabious) . When the pericarp is thin, and appears like a bladder surrounding the seed, the achene is termed a utricle, as in Amarantaceae . When the pericarp is extended in the form of a winged appendage, a See also:samara or samaroid achene is produced, as in the ash (fig. i) and common sycamore (fig . 21) . In these cases there are usually two achenes united, one of which, however, as in Fraxinus (fig . I), may be abortive . The wing surrounds the fruit longitudinally in the See also:elm . When the pericarp be-comes so incorporated with the seed as to be inseparable from it, as in grains of See also:wheat (fig . 22), See also:maize, oats and other See also:grasses, then the name caryopsis is given . The one-seeded portions (mericarps) of schizocarps often take the form of achenes, e.g. the mericarps of the From Vines' Students' Text-Book of Botany, by permission of Swan Sonnenschein & Co . mallows or of umbellifers (See also:figs . 24, 25) . In See also:Labiatae and See also:Boraginaceae (e.g. comfrey, fig . 23), where the bicarpellary ovary becomes our one-seeded portions in the fruit, the partial fruits are of the nature of achenes or nutlets according to the texture (leathery or hard) of the pericarp . The nut or glans is a dry one-celled indehiscent fruit with a hardened pericarp, often surrounded by bracts at the base, and, when mature, containing only one seed . In the See also:young See also:state the ovary often contains two or more ovules, but only one comes to maturity . It is illus- trated by the fruits of the hazel and See also:chestnut, which are covered by leafy bracts, in the form of a husk, and by the See also:acorn, in which the bracts and receptacle form a cupula or See also:cup (fig . 26) . The parts of the pericarp of the nut are united so as to appear one . In common language the term nut is very vaguely applied both to fruit and seeds . The drupe is a succulent usually one-seeded indehiscent fruit, with a pericarp easily distinguishable into epicarp, mesocarp and endocarp . This term is applied to such fruits as the cherry (fig . 5), peach, plum, See also:apricot or See also:mango . The endocarp is usually hard, form- See also:ing the stone (putamen) of the fruit, which encloses the kernel or seed . The mesocarp is generally pulpy and succulent, so as to be truly a sarcocarp, as in the peach, but it is sometimes of a tough texture, as in the See also:almond, and at other times is more or less fibrous, as in the coco-nut . In the almond there are often two ovules formed, only one of which comes to perfection . In the See also:raspberry and bramble several small drupes or drupels are aggregated so as to constitute an etaerio . The follicle is a dry unilocular many-seeded fruit, formed from one carpel and dehiscing by the ventral suture . It is rare to meet with a solitary follicle forming the fruit . There are usually several aggregated together, either in a whorl on a shortened receptacle, as in hellebore, See also:aconite, See also:larkspur, See also:columbine (figs . 27, 28) or the order See also:Crassulaceae, or in a spiral manner on an elongated receptacle, as in See also:Magnolia and See also:Banksia . Occasionally, follicles dehisce by the dorsal suture, as in Magnolia grandiflora and Banksia . The legume or pod is a dry monocarpellary unilocular many-seeded fruit, formed from one carpel; dehiscing both by the ventral and the Fin . 27 . FIG . 28 . FIG . 30 . dorsal suture . It characterizes leguminous plants, as the bean and pea (fig . 8) . In the bladder-senna it forms an inflated legume . In some See also:Leguminosae, as Arachis, Cathartocarpus Fistula and the See also:tamarind, the fruit must- be considered a legume, although it does not dehisce . The first of these plants produces its fruit under-ground, and is called See also:earth-nut; the second has a partitioned legume and is schizocarpic; and both the second and third have pulpy matter surrounding the seeds . Some legumes are schizocarpic by the formation of constrictions externally . Such a form is the lomentum or lomentaceous legume of Hedysarum (fig . 17), Coronilla, Ornithopus, Entada and of some Acacias . In Medicago the legume la . 9is See also:twisted like a See also:snail, and in Caesalpinia coriaria, or Divi-divi, it is vermiform or curved like a See also:worm . Sometimes the number of seeds is reduced, as in Erythrina monosperma and Geoffroya superba, which are one-seeded, and in Pterocarpus and Dalbergia, which are two-seeded . The See also:berry (bacca) is a term applied generally to all fruits with seeds immersed in pulp, and includes fruits of very various origin . In Actaea (See also:baneberry) or Berberis (See also:barberry) it is derived from a single free carpel; generally, how-ever, it is the product of a syncarpous ovary, which is See also:superior, as in grape or See also:potato, or inferior, as in gooseberry (fig . 29) Or See also:currant . In the pomegranate there is a See also:peculiar baccate many-celled inferior fruit, having a tough rind, enclosing two rows of carpels placed one above the other . The seeds are immersed in pulp, and are attached irregularly to the wall, base and centre of the loculi . In the See also:baobab there is a multi- FIG . 31.-Transverse See also:section locular syncarpous fruit, in which of the fruit of the Melon the seeds are immersed in pulp . (Cucumis Melo), showing the The pepo, another indehiscent placentas with the seeds attached syncarpous fruit, is illustrated by to them . The three carpels the fruit of the See also:gourd, melon (fig. forming the pepo are separated 31) and other See also:Cucurbitaceae . It by partitions . From the centre is formed of three carpels, sui- processes pass outwards, ending mounted by the calyx; the rind in the curved placenta . is thick and fleshy, and there are three or more seed-bearing parietal placentas, either surrounding a central cavity or prolonged inwards into it . The fruit of the papaw resembles the pepo, but the calyx is not superior . The hesperidium is the name given to such indehiscent fleshy syncarpous fruits as the orange, See also:lemon and See also:shaddock, in which the epicarp and mesocarp form a separable rind, and the endocarp sends prolongations inwards, forming triangular divisions, to the inner See also:angle of which the seeds are attached, pulpy cells being developed around them from the wall . Both pepo and hesperidium may be considered as modifications of the berry . The pome (fig . 30), seen in the apple, pear, See also:quince, medlar and See also:hawthorn, is a fleshy indehiscent syncarpous fruit, in the formation of which the receptacle takes part . The outer succulent part is the swollen receptacle, the horny core being the true fruit developed from the usually five carpels and enclosing the seeds . In the medlar the core (or true pericarp) is of a stony hardness, while the outer succulent covering is open at the See also:summit . The pome somewhat resembles the fruit of the rose (fig . 3), where the succulent receptacle surrounds a number of separate achenes . The name See also:capsule is applied generally to all dry syncarpous fruits, which dehisce by valves . It may thus be unilocular or multil ocular, one- or many-seeded . The true valvular capsule is observed in See also:Colchicum (fig . 9), lily and See also:iris (fig. l t) . The porose capsule is seen in the poppy (fig . 7), Antirrhinum and Campanula . In Campanula the pores occur at the base of the capsule, which becomes inverted when ripe . When the capsule opens by a lid, or by circumscissile dehiscence, it is called a pyxidium, as in pimpernel (A nagallis arvensis) (fig. i6), henbane and See also:monkey-pot (Lecythis) . The capsule assumes a See also:screw-like form in Helicteres, and a See also:star-like form in star-See also:anise (Illiciotm anisatum) . In certain instances the cells of the capsule separate from each other, and open with elasticity to scatter the seeds . This See also:kind of capsule is met with in the sandbox See also:tree (Hura crepitans) and other Euphorbiaceae, where the cocci, containing each a single seed, burst asunder with force; and in Geraniaceae, where the cocci, each containing, when mature, usually one seed, separate from the carpophore, become curved upwards by their adherent styles, and open by the ventral suture (fig . 18) . 
The siliqua is a dry syncarpous bilocular many-seeded fruit, formed from two carpels, with a false septum, dehiscing by two valves from below upwards, the valves separating from the placentas and leaving them united by the septum (fig . 32) . The seeds are attached on both sides of the septum, either in one row or in two . When the fruit is long and narrow it is a siliqua (fig . 14) ; when broad and short, silicula (fig . 33) . It occurs in cruciferous plants, as wall-flower, See also:cabbage and See also:cress . In Glaucium and Eschscholtzia (Papaveraceae) the dissepiment is of a spongy nature . It may become transversely constricted (lomentaceous), as in See also:radish (Raphanus) and sea-kale, and it may be reduced, as in See also:woad (Isatis), to a one-seeded See also:condition . It sometimes happens that the ovaries of two flowers unite so as to form a See also:double fruit (syncarp) . This may be seen in many See also:species of See also:honeysuckle . But the fruits which are now to be considered consist usually of the floral envelopes, as well as the ovaries of several flowers united into one, and are called multiple or confluent . The term anthocarpous has also been applied as indicating that the floral envelopes as well as the carpels are concerned in the formation of the fruit . The sorosis is a succulent multiple fruit formed by the confluence II From Strasburger's Lehrbuch der Botanik, by permission of Gustav Fischer . of a spike of flowers, as in the fruit of the See also:pine-apple (fig . 34), the See also:bread-fruit and See also:jack-fruit . Similarly the fruit of the mulberry represents a catkin-like inflorescence . The syconus is an anthocarpous fruit, in which the receptacle completely encloses numerous flowers and becomes succulent . The fig (fig . 4) is of this nature, and what are called its seeds are the achenes of the numerous flowers scattered over the succulent hollowed receptacle . In Dorstenia the axis is less deeply hollowed, and of a harder texture, the fruit exhibiting often very anomalous forms . The strobilus, or See also:cone, is a seed-bearing spike, more or less elongated, covered with scales, each of which may be regarded as representing a separate flower, and has often two seeds at its base; the seeds are naked, no ovary being See also:present . This fruit is seen in the cones of firs, spruces, larches and cedars, which have received thein the plants called angiospermous; while in gymnospermous plants, such as Coniferae and Cycadaceae, it is naked, or, in other words. has no true pericarp . It sometimes happens in See also:Angiosperms, that the seed-See also:vessel is ruptured at an See also:early See also:period of growth, so that the seeds become more or less exposed during their development ; this occurs in See also:mignonette, where the capsule opens at the apex, and in Cuphea, where the placenta bursts through the ovary and floral envelopes, and appears as an erect process bearing the young seeds . After fertilization the ovule is greatly changed, in connexion with the formation of the embryo . In the embryo-See also:sac of most Angiosperms (q.v.) there is a development of cellular tissue, the endosperm, more or less filling the embryo-sac . In See also:Gymnosperms (q.v.) the endosperm is formed preparatory to fertilization . The fertilized See also:egg enlarges and becomes multicellular, forming the embryo . The embryo-sac enlarges greatly, displacing gradually the surrounding nucellus, which eventually forms merely a thin layer around the sac, or completely disappears . The See also:remainder of the nucellus and the integuments of the ovules form the seed-coats . In some cases (fig . 35) a delicate inner coat or tegmen can be distinguished from a tougher outer coat or testa; often, however, the layers are not thus separable . The consistency of the seed-coat, its thickness, the See also:character of its surface, &c., vary widely, the See also:variations being often closely associated with the environment or with the means of seed-dispersal . An See also:account of the development of the seed from the ovule will be found in the See also:article ANGIOSPERMS . When the pericarp is dehiscent the seed-covering is of a strong and often rough character; but when the pericarp is indehiscent and encloses the seed for a long period, the outer seed-coat is thin and soft . The cells of the testa are often coloured, and have projections and appendages of various kinds . Thus in Abrus precatorius and Adenanthera pavonina it is of a bright red colour; in See also:French beans it is beautifully mottled; in the almond it is veined; in the See also:tulip 9 t r From Strasburger's Lehrbuch der Boianik, by permission of Gustav Fischer . From Strasburger's Lehrbuch der Botanik, by permission of Gustav Fischer . name of Coniferae, or cone-bearers, on this account . Cone-like fruit is also seen in most Cycadaceae . The scales of the strobilus are sometimes thick and closely united, so as to form a more or less angular and rounded mass, as in the See also:cypress; while in the juniper they become fleshy, and are so incorporated as to form a globular fruit like a berry . The dry fruit of the cypress and the succulent fruit of the juniper have received the name of galbulus . In the See also:hop the fruit is called also a strobilus, but in it the scales are thin and membranous, and the seeds are not naked but are contained in pericarps . The same causes which produce alterations in the other parts of the flower give rise to anomalous appearances in the fruit . The carpels, in place of bearing seeds, are sometimes changed into leaves, with lobes at their margins . Leaves are sometimes produced from the upper part of the fruit . In the genus Citrus, to which the orange and lemon belong, it is very common to meet with a separation of the carpels, so as to produce what are called horned oranges and fingered citrons . In this case a syncarpous fruit has a tendency to become apocarpous . In the orange we occasionally find a supernumerary row of carpels produced, giving rise to the appearance of small and imperfect oranges enclosed within the See also:original one; the See also:navel orange is of this nature . It sometimes happens that, by the See also:union of flowers, double fruits are produced . Occasionally a double fruit is produced, not by the See also:incorporation of two flowers, but by the abnormal development of a second carpel in the flower . Arrangement of Fruits . A . True fruits—developed from the ovary alone . 1 . Pericarp not fleshy or fibrous . i . Indehiscent—not opening to allow the escape of the seeds—generally one-seeded . Aehene; caryopsis; cypsela; nut; schizocarp . ii . Dehiscent—the pericarp splits to allow the escape of the seeds—generally many-seeded . Follicle; legume; siliqua; capsule . 2 . Pericarp generally differentiated into distinct layers, one of which is succulent or fibrous . Drupe; berry . B . Pseudocarps—the development extends beyond the ovary . Pome; syconus; sorosis . The Seed.—The seed is formed from the ovule as the result of fertilization . It is contained in a seed-vessel formed from the ovary ch and See also:primrose it is rough; in the See also:snapdragon it is marked with depressions; in See also:cotton and Asclepias (fig . 36) it has hairs attached to it; and in See also:mahogany, Bignonia, and the pines and firs it is See also:expanded in the form of wing-like appendages (fig . 37) . In Collomia, Acanthodium, Cobaea scandens and other seeds, it contains spiral cells, from which, when moistened with water, the See also:fibres uncoil in a beautiful manner; and in flax (Linum) and others the cells are converted into See also:mucilage . These structural peculiarities of the testa in different plants have relation to the scattering of the seed and its germination upon a suitable nidus . But in some plants the pericarps assume structures which subserve the same purpose; this especially occurs in small pericarps enclosing single seeds, as achenes, caryopsides, &c . Thus in Compositae and See also:valerian, the pappose See also:limb of the calyx forms a See also:parachute to the pericarp; in Labiatae and some Compositae spiral cells are formed in the epicarp; and the epicarp is prolonged as a wing in Fraxinus (fig . I) and Acer (fig . 21) . Sometimes there is an additional covering to the seed, formed after fertilization, to which the name arillus has been given (fig . 38) . This is seen in the See also:passion-flower, where the covering arises from the placenta .or extremity of the funicle at the base of the ovule and passes upwards towards the apex, leaving the micropyle uncovered . In the See also:nutmeg and spindle tree this additional coat is formed from above downwards, constituting in the former case a laciniated scarlet covering called See also:mace . In such instances it has been called an arillode (fig . 39) .
This arillode, after growing downwards, may be reflected upwards so as to See also:cover the micropyle
.
The fleshy scarlet covering formed around the naked seed in the See also:yew is by some considered of the nature of an aril
.
On the testa, at various points, there are produced at times other cellular bodies, to which the name of strophioles, or caruncles, has been given, the seeds being strophiolate or carunculate
.
These tumours may occur near the base of the seed, as in Polygala, or at the apex, as in Castor-oil plant (Ricinus) ; or they may occur in the course of the raphe, as in See also:blood-See also:root ,Sanguinaria) and Asarabacca
.
The funicles of the ovules frequently attain a great length in the seed, and in some magnolias, when the fruit dehisces, they appear as long scarlet cords suspending the seeds outside
.
The hilum or umbilicus of the seed usually
well marked, as a scar of varying size; in the See also:calabar bean and in some species of See also:Mucuna and Dolichos it extends along a large portion of the edge of the seed; it frequently exhibits marked See also:colours, being See also:black in the bean, See also:
In the orange (fig
.
40) it is of a reddish-See also: It occupied the whole cavity of the embryo-sac, or is formed only at certain portions of it, at the apex, as in Rhinanthus, at the base, as in Vaccinium, or in the middle, as in See also:Veronica . As the endosperm increases in size along with the embryo-sac and the embryo, the substance of the original nucellus of the ovule is gradually absorbed . Sometimes, however, as in Musaceae, Cannaceae, Zingiberaceae, no endosperm is formed; the cells of the original nucellus, becoming filled with food-materials for the embryo, are not absorbed, but remain surrounding the embryo-sac with the embryo, and constitute the perisperm . Again, in other plants, as Nymphaeaceae (fig . 38) and Piperaceae, both endosperm and perisperm are present . It was from observations on cases such as these that old authors, imagining a resemblance betwixt the plant-ovule and the animal ovum, applied the name albumen to the outer nutrient mass or perisperm, and designated the endosperm as vitellus . The term albumen is very generally used as including all the nutrient matter stored up in the seed, but it would be advisable to discard the name as implying a definite chemical substance . There is a large class of plants in which although at first after fertilization a mass of endosperm is formed, yet, as the embryo increases in size, the nutrient matter from the endospermic cells passes out from them, and is absorbed by the cells of the embryo plant . In the mature seed, in such cases, there is no separate mass of tissue containing nutrient food-material apart from the embryo itself . Such a seed is said to be exalbuminous, as in Compositae, Cruciferae and most Leguminosae (e.g. pea, fig . 35) . When either endosperm or perisperm or both are present the seed is said to be albuminous . The albumen varies much in its nature and consistence, and furnishes important characters . It may be farinaceous or mealy, consisting chiefly of cells filled with See also:starch, as in cereal grains, where it is abundant; fleshy or cartilaginous, consisting of thicker cells which are still soft, as in the coco-nut, and which sometimes contain oil, as in the oily albumen of Croton, Ricinus and poppy; horny, when the cell-walls are slightly thickened and capable of distension, as in date and See also:coffee; the cell-walls sometimes become greatly thickened, filling up the testa as a hard mass, as in See also:vegetable See also:ivory (Phytelephas) . The albumen may be See also:uniform throughout, or it may present a mottled appear- y I ance, as in the nutmeg, the seeds of Anonaceae and some Palms, where it is called ruminated . This mottled appearance is due to a protrusion of a dark lamella of the integument between folded protuberances of albumen . A cavity is sometimes See also:left in the centre which is usually filled with ffuid, as in the coco-nut . The relative size of the embryo and of the endosperm varies much . In Monocotyledons the embryo is usually small, and the endosperm large, and the same is true in the case of coffee and many other plants amongst See also:Dicotyledons . The opposite is the case in other plants, as in the Labiatae, Plumbaginaceae, &c . The embryo consists of an axis bearing the cotyledons (fig . 42, c), or the first leaves of the plant . To that part of this axis immediate) beneath the cotyledons the terms hypocotyl, caulicle or tigellum (t) have been applied, and continuous backwards with it is the young root or radicle (r), the descending axis, their point of union being the See also:collar or See also:neck . The terminal growing bud of the axis is called the plumule or gemmule (g), and represents the ascending axis . The radicular extremity points towards the micropyle, while the cotyledonary extremity is pointed towards the base of the ovule or the chalaza . Hence, by ascertaining the position of the micropyle and chalaza, the two extremities of the embryo can in general be discovered . It is in many cases difficult to recognize the parts in an embryo; thus in Cuscuta, the embryo appears as an elongated axis without divisions; and in Caryocar the mass of the embryo is made up by the radicular extremity and hypocotyl, in a groove of which the cotyledonary extremity lies embedded (fig . 52) . In some monocotyledonous embryos, as in Orchidaceae, the embryo is a cellular mass showing no parts . In parasitic plants also which form no See also:chlorophyll, as Orobanche, Monotropa, &c., the embryo remains without differentiation, consisting merely of a mass of cells until the ripening of the seed . When the embryo is surrounded by the endosperm on all sides except its radicular extremity it is internal (see figs . 19, 20) ; when lying outside the endosperm, and only coming into contact with it at certain points, it is external, as in grasses (e.g. wheat, fig . 22) . When the embryo follows the direction of the axis of the seed, it is See also:axile or axial (fig . 43) ; when it is not in the direction of the axis, it becomes abaxile or abaxial . In campylotropal seeds the embryo is curved, and in place of being embedded in endosperm, is frequently external to it, following the concavity of the seed (fig . 44), and becoming peripherical, with the chalaza situated in the curvature of the embryo, as in Caryophyllaceae . It has been already stated that the radicle of the embryo is directed to the micropyle, and the cotyledons to the chalaza . In some cases, by the growth of the integuments, the former is turned round so as not to correspond with the apex of the nucellus, and then the embryo has the radicle directed to one side, and is called excentric, as is seen in See also:Primulaceae, Plantaginaceae and many palms, especially the date . The position of the embryo in different kinds of seeds varies . In an orthotropal seed the embryo is inverted or anttropal, the radicle pointing to the apex of the seed, or to the part opposite the hilum . Again, in an anatropal seed the embryo is erect or homolro al (fig . 43), the radicle being directed to the base of the seed . In curved or campylotropal seeds the embryo is folded so that its radicular and cotyledonary extremities are approximated, and it becomes amphitropal (fig . 44) . In this instance the seed may be exalbuminous, and the embryo may be folded on itself; or albuminous, the embryo surrounding more or less completely the endosperm and being peripherical . According to the mode in which the seed is attached to the pericarp, the radicle may be directed upwards or downwards, or laterally, as regards the ovary . In an orthotropal seed attached to the base of the pericarp it is superior, as also in a suspended anatropal seed . In other anatropal seeds the radicle is inferior . When the seed is horizontal as regards the pericarp, the radicle is either centrifugal, when it points to the outer wall of the ovary; or centripetal, when it points to the axis or inner wall of the ovary . These characters are of value for purposes of See also:classification, as they are often See also:constant in large See also:groups of genera . Plants in which there are two cotyledons produced in the embryo are dicotyledonous . The two cotyledons thus formed are opposite to each other (figs . 42 and 45), but are not always of the same size . Thus, in Abronia and other members of the order Nyctaginaceae, one of them is smaller than the other (often very small), and in Carapa guianensis there appears to be only one, in consequence of the intimate union which takes place between the two . The union between the cotyledonary leaves may continue after the young plant begins to germinate . Such embryos have been called pseudomonocotyledonous . The texture of the cotyledons varies . They may be thick, as in the pea (fig . 42), exhibiting no traces of venation, with their flat internal surfaces in contact, and their backs more or less convex; or they may be in the form of thin and delicate laminae, flattened on both sides, and having distinct venation, as in Ricinus, Jatropha, See also:Euonymus, &c . The cotyledons usually form the greater part of the mature embryo, and this is remarkably well seen in such exalbuminous seeds as the bean and pea . Cotyledons are usually entire and sessile . But they occasionally become lobed, as in the See also:walnut and the See also:lime; or petiolate, as in See also:Geranium molle; or auriculate, as in the ash . Like leaves in the bud, cotyledons may be either applied directly to each other, or may be folded in various ways . In geranium the cotyledons are twisted and doubled; in convolvulus they.are corrugated; and in the potato and in Bunias, they are spiral,—the same terms being applied as to the foliage leaves . The radicle and cotyledons are either straight or variously curved . Thus, in some cruciferous plants, as the wallflower, the cotyledons are applied by their faces, and the radicle (figs . 46, 47) is folded on their edges, so as to be lateral; the cotyledons are here accumbent . In others, as Hesperis, the cotyledons (fig . 48) are applied to each other by their faces, and the radicle, r, is folded on their back, so as to be dorsal, and the cotyledons are See also:incumbent . Again, the cotyledons are con-duplicate when the radicle is dorsal, and enclosed between their folds . In other divisions the radicle is folded in a spiral manner, and the cotyledons follow the same course . In many gymnosperms more than two cotyledons are present, and they are arranged in a whorl . This occurs in Coniferae, especially in the pine, See also:fir (fig . 49), spruce and See also:larch, in which six, nine, twelve and even fifteen have been observed . They are linear, and resemble in their form and mode of development the clustered or fasciculated leaves of the larch . Plants having numerous cotyledons are termed polycotyledonous . In species of Streptocarpus the cotyledons are permanent, and See also:act the part of leaves . One of them is frequently largely developed, while the other is small or abortive . In those plants in which there is only a single cotyledon in the embryo, hence called monocotyledonous, the embryo usually has a cylindrical form more or less rounded at the extremities, or elongated and fusiform, often oblique . The axis is usually very short compared with the cotyledon, which in general encloses the plumule by its lower portion, and exhibits on one side a small slit which indicates the union of the edges of the vaginal or sheathing portion of the leaf (fig . 5o) . In grasses, by the enlargement of the embryo in a particular direction, the endosperm is pushed on one side, and thus the embryo comes to See also:lie outside at the base of the endosperm (figs . 22, 51) . The lamina of the cotyledon is not developed . Upon the side of the embryo next the endosperm and enveloping it is a large See also:shield-shaped body, termed the scutellum . This is an outgrowth from the base of the cotyledon, enveloping more or less the cotyledon and plumule, in some cases, as in maize, completely investing it; in other cases, as in See also:rice, merely sending small prolongations over its anterior face at the apex . By others this scutellum is considered as the true cotyledon, and the sheathing structure covering the plumule is regarded as a ligule or axillary stipule (see GRASSES) . In many aquatic monocotyledons (e.g . Potamogeton, Ruppia and others) there is a much-developed hypocotyl, which forms the greater part of the embryo and acts as a See also:store of nutriment in germination; these are known as macropodous embryos . A similar case is that of Caryocar among Dicotyledons, where the swollen hypocotyl occupies most of the embryo (fig . 52) . In some grasses, as oats and rice, a See also:projection of cellular tissue is seen upon the side of the embryo opposite to the scutellum, that is, on the anterior side . This has been termed the epiblast . It is very large in rice . This by some was considered the rudimentary second cotyledon; but is now generally regarded as an outgrowth of the sheath of the true cotyledon . (A . B . |
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