Under the head of malformations we place cases of atrophy of parts or general dwarfing, due to starvation, the attacks of Fungi or minute insects, the presence of unsuitable food-materials and so on, as well as cases of transformation of stamens into petals, carpels into leaves, and so forth.
Exclusively female flowers without stamens do not appear to have been observed.
The vivid scarlet single form flowers open to reveal bright yellow stamens at their heart.
The five stamens alternate in position with the lobes of the corolla.
This arrangement may be understood by reference to the following diagram, representing the relative position of the stamens in orchids generally and in Cypripedium.
The letter L indicates the position of the labellum; the large figures indicate the developed stamens; the italic figures show the position of the suppressed stamens.
I 4 5 6 2 L 3 2 L 3 Arrangement of stamens Arrangement of stamens in Orchis.
in diameter, and bear in the axil a solitary, stalked, white flower, about the size and shape of the garden anemone, with six or more petals and twice as many hypogynous stamens.
from light 1, Corolla cut open with stamens.
s, s, The two stamens.
The spores, as in the heterosporous Pteridophyta, are of two kindsmicrospores (pollen grains) borne in microsporangia (pollen sacs) on special leaves (sporophylls) known as stamens, and macrospores (embryo-sac) borne in macrosporangia (ovules) on sporophylls known as carpels.
In some orders the parts are numerous, chiefly in the case of the stamens and the carpels, as in the buttercup and other members of the order Ranunculaceae.
Floral diagram of typical orchid flower; 1, labellum; a, anther; s, rudiments of barren stamens (staminodes).
In Cypripedium two stamens are present, one on each side of the column instead of one only at the top, as in the group Monandreae, to which belong the remaining genera in which also only two stigmas are fertile.
What may be considered the normal number of stamens is, as has been said, six, arranged in two rows.
In Cypripedium two of the outer stamens are wanting; the third - the one, that is, which corresponds to the single fertile stamen in the Monandreae - forms a large sterile structure or staminode; the two lateral ones of the inner series are present, the third being undeveloped.
From the upper rim of the receptacle are given off the five sepals, the five petals, and the very numerous stamens.
Many Thomisidae lurk amongst the stamens and petals of flowers, which they closely match in colour, waiting to seize the insects which visit the blossoms for nectar.
The flowers, which are borne in the leaf-axils at the ends of the stem, are very handsome, the six, generally narrow, petals are bent back and stand erect, and are a rich orange yellow or red in colour; the six stamens project more or less horizontally from the place of insertion of the petals.
The flowers have a hollow tube at the base bearing at its free edge five sepals, an equal number of petals, usually concave or spoon-shaped, pink or white, and a great number of stamens.
The flowers are regular, with four free sepals arranged in two pairs at right angles, four petals arranged crosswise in one series, and two sets of stamens, an outer with two members and an inner with four, in two pairs placed in the middle line of the flower and at right angles to the outer series.
The four inner stamens are longer than the two outer; and the stamens are hence collectively described as tetradynamous.
The petals are generally white or yellow, more rarely lilac or some other colour, and between the bases of the stamens are honey-glands.
The flowers, which are solitary, or rarely in pairs, at the end of slender axillary flower-stalks, are very irregular in form, with five sepals prolonged at the base, and five petals, the lowest one larger than the others and with a spur, in which collects the honey secreted by the spurs of the two adjoining stamens.
- Two Stamens of Viola tricolor (Pansy), with their two anther lobes and the processp extending beyond them.
One of the stamens has been deprived of its spur; the other shows its spur, c. a row down the centre, are shot out to some little distance from she parent plant.
b, pair of bracteoles below the flower; s, sepals; p, petals; st, stamens; o, ovary.
evergreen shrub with flattened leaf-like cladodes, native in the southerly portion of England and Wales; the small flowers are unisexual and borne on the face of the cladode; the male contains three stamens, the filaments of which are united to form a short stout column on which are seated the diverging cells of the anthers; in the female the ovary is enveloped by a fleshy staminal tube on which are borne three barren anthers.
terminating the short annual shoot which bears a whorl of four or more leaves below the flower; in this and in some species of the nearly allied genus Trillium (chiefly temperate North America) the flowers have a fetid smell, which together with the dark purple of the ovary and stigmas and frequently also of the stamens and petals, attracts carrion-loving flies, which alight on the stigma and then climb the anthers and become dusted with pollen; the pollen is then carried to the stigmas of another flower.
The parts of the flower are in fives in calyx, corolla and stamens, followed by two carpels which unite to form a superior ovary.
The slender filaments of the stamens vary widely, often in the same flower; the anthers are linear to ovate in shape, attached at the back to the filament, and open lengthwise.
Each has a small calyx in the form of a shallow rim, sometimes five-lobed or toothed; five petals, which cohere by their tips and form a cap or hood, which is pushed off when the stamens are ripe; and five free stamens, placed opposite the petals and springing from a fleshy ring or disk surrounding the ovary; each bears a twocelled anther.
The anomalous position of the stamens in front of the petals is explained by the abortion or non-development of an outer row of stamens, indications of which are sometimes seen on the hypogynous disk encircling the ovary.
The perianth consists of five or six oblong greenish lobes, within which is found a tuft, consisting of a large number of stamens, each of which has a very short filament and an oblong two-lobed anther bursting longitudinally, and surmounted by an oblong lobe, which is the projecting end of the connective.
The flowers are regular, with a perianth springing from above the ovary, tubular below, with spreading segments and a central corona; the six stamens are inserted within the tube.
In the male flowers, which are numerous, the stamens are sixteen in number and arranged in pairs; the female flowers are solitary, with traces of stamens, and a smooth ovary with one ovule in each of the eight cells - the ovary is surmounted by four styles, which are hairy at the base.
Each male flower consists of a small scale or bract, in the axil of which are usually two, sometimes three, rarely five stamens, and still more rarely a larger number.
increase in size upwards, and at length become crowded, numerous and petaloid, forming a funnel-shaped blossom, the beauty of which is much enhanced by the multitude of conspicuous stamens which with the pistil occupy the centre.
The sepals and petals are free or more or less united, the stamens as many or twice as many as the petals; the carpels, usually free, are equal to the petals in number, and form in the fruit follicles with two or more seeds.
The system of Linnaeus was founded on characters derived from the stamens and pistils, the so-called sexual organs of the flower, and hence it is often called the sexual system.
Nehemiah Grew seems to have been the first to describe, in a paper on the Anatomy of Plants, read before the Royal Society in November 1676, the functions of the stamens and pistils.
Camerarius, professor of botany and medicine at Tubingen, published a letter on the sexes of plants, in which he refers to the stamens and pistils as the organs of reproduction, and states the difficulties he had encountered in determining the organs of Cryptogamic plants.
In the latter division of plants he could not detect stamens and pistils, and he did not investigate the mode in which their germs were produced.
The structure of the flower represents the simple type of monocotyledons, consisting of two whorls of petals, of three free parts each, six free stamens, and a consolidated pistil of three carpels, ripening into a three-valved capsule containing many winged seeds.
The cup-shaped flowers have six regular segments in two rows, as many free stamens, and a three-celled ovary with a sessile stigma, which ripens into a leathery many-seeded capsule.
The method of pollination is to some extent governed by the distribution of the stamens and pistil.
In bisexual or hermaphrodite flowers, that is, those in which both stamens and pistil are present, though self-pollination might seem the obvious course, this is often prevented or hindered by various arrangements which favour cross-pollination.
Flowers in which the relative position of the organs allows of spontaneous self-pollination may be all alike as regards length of style and stamens (homomorphy or homostyly), or differ in this respect (heteromorphy) the styles (From Strasburger's by permission of Gustav Fischer.) FIG.
and stamens being of different lengths in different flowers (heterostyly) or the stamens only are of different lengths (heteranthery).
Xenogamy is of course the only possible method in diclinous plants; it is also the usual method in monoclinous plants, owing to the fact that stamens and carpels often mature at different times (dichogamy), the plants being proterandrous or proterogynous.
In Broom there is an explosive machanism; the pressure of the insect visitor on the keel of the corolla causes a sudden release of the stamens and the scattering of a cloud of pollen over its body.
Within these are six stamens, a hairy ovary surmounted by two feathery styles which ripens into the fruit (grain), and which is invested by the husk formed by the persistent glume and pale.
In Geranium the stamens are obdiplostemonous, i.e.
an outer whorl of five opposite the petals alternates with an inner whorl of five opposite the sepals; at the base of each of the antisepalous stamens is a honey-gland.
There is no satisfactory explanation of this break in the regular alternation of successive whorls; the outer whorl' of stamens arises in course of development before the inner, so that there is no question of subsequent displacement.
pratense, each whorl of stamens ripens in turn, becoming erect and shedding their pollen; as the anthers wither the filaments bend outwards, and when all the anthers have diverged the stigmas become mature and ready for pollination.
1 and 2 opposite the inner stamens.
arrangement self-pollination is prevented and cross-pollination ensured by the visits of bees which come for the honey secreted by the glands at the base of the inner stamens.
self-pollination is rendered possible, since the divisions of the stigma begin to separate before the outer stamens have shed all their pollen; the nearness of the stigmas to the dehiscing anthers favours self-pollination.
It must suffice here to say that double flowers are most commonly the result of the substitution of brightly-coloured petals for stamens or pistils or both, and that a perfectly double flower where all the stamens and pistils are thus metamorphosed is necessarily barren.
In the simplest instances the pollen of one flower fertilizes the ovules of another on the same plant, owing to the stamens arriving at maturity in any one flower earlier or later than the pistils.
To prevent self-fertilization, or the access of insects, it is advisable to remove the stamens and even the corolla from the flower to be impregnated, as its own pollen or that of a flower of the same species is often found to be " prepotent."
aquilegifolium, 2 ft., purplish from the conspicuous stamens, the leave's glaucous, is a good border plant; and T.
The stamens are short, numerous and inserted at the base of the corolla; the anthers are large and yellow, and the long style ends in three branches.
The numerous stamens surround the ovary, which is composed of 4 to 16 carpels and is surmounted by a flat or convex rayed disk bearing the stigmas.
These, as in Gymnosperms, are of two kinds, microspores or pollen-grains, borne in the stamens (or microsporophylls) and megaspores, in which the egg-cell is developed, contained in the ovule, which is borne enclosed in the carpel (or megasporophyll).
The flower may consist only of spore-bearing leaves, as in willow, where each flower comprises only a few stamens or two carpels.
The former comprise three classes, which are distinguished by the relative position of the stamens and ovary; the eleven classes of the latter are based on the same set of characters and fall into the larger subdivisions Apetalae, Monopetalae and Polypetalae, characterized respectively by absence, union or freedom of the petals, and a subdivision, Diclines Irregulares, a very unnatural group, including one class only.
Of the Polypetalae, series i, Thalamiflorae, is characterized by hypogynous petals and stamens, and contains 34 orders distributed in 6 larger groups or cohorts.
Series 3, Calyciflorae, has petals and stamens perigynous, or sometimes superior.
Of the Gamopetalae, series i, Inferae, has an inferior ovary and stamens usually as many as the corolla-lobes.
Series 2, Heteromerae, has generally a superior ovary, stamens as many as the corolla-lobes or more, and more than two carpels.
The petaloid perianth consists of two series, each with three members, which are joined below into a longer or shorter tube, followed by one whorl of three stamens; the inferior ovary is three-celled and contains numerous ovules on an axile placenta; the style is branched and the branches are often petaloid.
The arrangement of the parts in the flower resembles that in the nearly allied order Amaryllidaceae (Narcissus, Snowdrop, &c.), but differs in the absence of the inner whorl of stamens.
inner petals (a) and stamens.
The five stamens spring from the corolla-tube and are FIG.
opposite to its lobes; this anomalous position is generally explained by assuming that an outer whorl of stamens opposite the sepals has disappeared, though sometimes represented by scales as in Samolus and Soldanella.
Another explanation is based on the late appearance of the petals in the floral development and their origin from the backs of the primordia of the stamens; it is then assumed that three alternating whorls only are present, namely, sepals, stamens bearing petal-like dorsal outgrowths, and carpels.
The two forms have long and short styles repectively, the stamens occupying corresponding positions half-way down or at the mouth of the corolla-tube; the long-styled flowers have smaller pollen-grains, which correspond with smaller stigmatic papillae on the short styles.
The stamens are shorter than the cup,.
in diameter, with five spreading white petals alternating with five persistent green sepals, a large number of stamens with pinkish-brown anthers, and one to three carpels sunk in the cup-shaped floral axis.
3 is a single spikelet of the same, containing two florets, with the three stamens of one only protruded.
- Stamens and Pistil of Sweet Pea (Lathyrus).
The stamens are diadelphous, nine of them being united by their filaments f, while the uppermost one (e) is free; st, stigma, c, calyx.
encloses the stamens and pistil, protecting them from rain and the attacks of unbidden polleneating insects.
In his book on the fertilization of flowers, Hermann Muller distinguishes four types of papilionaceous flowers according to the way in which the pollen is applied to the bee: (I) Those in which the stamens and stigma return within the carina and thus admit of repeated visits, such are the clovers, Melilotus and laburnum.
(2) Explosive flowers where stamens I, Calyx.
The irregular flowers have five sepals united at the base, the dorsal one produced into a spurred development of the axis; of the five petals the two upper are slightly different and stand rather apart from the lower three; the eight stamens are unequal and the pistil consists of three carpels which form a fleshy fruit separating into three one-seeded portions.
- Catkin of Hazel (Corylus Avellana), consisting of an axis covered with bracts in the form of scales, each of which covers a male flower, the stamens of which are seen projecting beyond the scale.
The flowers are regular and symmetrical, having five sepals, tapering to a point and hairy on the margin, five petals which speedily fall, ten stamens, and a pistil bearing five distinct styles.
They are shrubs or low trees with evergreen or nearly evergreen opposite entire leaves, and dense clusters of small, white, tubular four-parted flowers, enclosing two stamens and succeeded by small, globular, usually black berries, each with a single pendulous seed.
In a few cases two whorls of stamens are present, with three members in each, but generally only three are present; the pistil consists of three or two carpels, united to form an ovary bearing a corresponding number of styles and containing one ovule.
Some of the flowers are often imperfect, the stamens or pistil being more or less aborted.
The flower differs from that of the majority of grasses in having usually three lodicules and six stamens.
The staminate contain 8 to 20 stamens which produce an enormous amount of dusty yellow pollen, some of which gets carried by wind to the protruding stigmas of the pistillate flowers.
Above the ring of stamens is the ovary itself, upraised on a prolongation of the same stalk which bears the filaments, or sessile.
The stalk supporting the stamens and ovary is called the "gynophore" or the "gynandrophore," and is a characteristic of the order.
In the vast majority there are three stamens alternating with the lodicules, and therefore one anterior, i.e.
The stamens become numerous (ten to forty) in the male flowers of a few monoecious genera (Pariana, Luzieta).
r 5), it will be seen to differ in the absence of the outer row and the posterior member of the inner row of the perianth-leaves, of the whole inner row of stamens, and of the two lateral carpels, FIG.
f, Outer row of stamens.
The spikelets are sometimes unisexual, and there are often six stamens.
- Like Zamia, except that the ends of the stamens are flat, while the apices of the carpels are peltate.
The sporangia (pollen-sacs), which occur on the under-side of the stamens, are often arranged in more or less definite groups or sori, interspersed with hairs (paraphyses); dehiscence takes place along a line marked out by the occurrence of smaller and thinner-walled cells bounded by larger and thickerwalled elements, which form a fairly prominent cap-like " annulus " near the apex of the sporangium, not unlike the annulus characteristic of the Schizaeaceae among ferns.
A, Male flower; B, C, single stamens; D, female flower.
The axis of the flower is a shoot bearing leaves in the form of stamens.
A typical male flower consists of a central axis bearing numerous spirally-arranged sporophylls (stamens), each of which consists of a slender stalk (filament) terminating distally in a more or less prominent knob or triangular scale, and bearing two or more pollen-sacs (microsporangia) on its lower surface.
The stamens of Araucaria and Agathis are peculiar in bearing several long and narrow free pollen-sacs; these may be compared with the sporangiophores of the horsetails (Equisetum); in Taxus (yew) the filament is attached to the centre of a large circular distal expansion, which bears several pollen-sacs on its under surface.
16), in which the lower part bears stamens and the upper portion carpellary and seminiferous scales.
An interesting case has been figured by Masters, in which scales of a cone of Cupressus Lawsoniana bear ovules on the upper surface and stamens on the lower face.
Each cone consists of an axis, on which numerous broad and thin bracts are arranged in regular rows; in the axil of each bract occurs a single flower; a male flower is enclosed by two opposite pairs of leaves, forming a perianth surrounding a central sterile ovule encircled by a ring of stamens united below, but free distally as short filaments, each of which terminates in a trilocular anther.
The flowers are regular and rather showy, generally with three greenish sepals, followed in regular succession by three white or purplish petals, six to indefinite stamens and six to indefinite free carpels.
Within these are three stamens surrounding a compressed ovary, with two feathery stigmas.
These contain three stamens with thread-like filaments and oblong, two-lobed anthers.
The stamens are placed round the base of the ovary, which is rounded or oblong, much smaller than the glumes, covered with down, and surmounted by two short styles, extending into feathery brush-like stigmas.
Under natural circumstances wheat is selffertilized: that is to say, the pollen of any given flower impregnates the stigma and ovule of the same flower; the glumes and coverings of the flower being tightly pressed round the stamens and stigmas in such a way as to prevent the access of insects and to ensure the deposit of the pollen upon the stigmas of the same flower.
The stamens of the wheat plant may frequently be seen protruding beyond the glumes, and their position might lead to the inference that cross-fertilization was the rule; but on closer examination it will be found that the anthers are empty or nearly so, and that they are not protruded till after they have deposited the pollen upon the stigma.
The separation of the glumes, which occurs at the time of fertilization, and which permits the egress of the useless stamens after that operation, occurs only under certain conditions of temperature, when the heat, in fact, is sufficient to cause the lodicules of the flower to become turgid and thus to press apart the glumes.
Another type s, Rudimentary stamens.
The flowers spring from, or are enclosed in, a spathe, and are unisexual and regular, with generally a calyx and corolla, each of three members; the stamens are in whorls of three, the inner whorls are often barren; the two to fifteen carpels form an inferior ovary containing generally numerous ovules on often large, produced, parietal placentas.
2), which is also dioecious, the small male flowers are borne in large numbers in shortstalked spathes; the petals are minute and scalelike, and only two of the three stamens are fertile; the flowers become detached before opening and rise to the surface, where the sepals expand and form a float bearing the two projecting semi-erect stamens.
2, Stamens, enlarged.
Petals multiplied at the expense of the stamens, which are reduced in number.
The conversion of bracts into stamens (staminody of bracts) has been observed in the case of A bies excelsa.
- Amentum or catkin of Hazel (CorylusAvellana), consisting of an axis or rachis covered with bracts in the form of scales, each of which covers a male flower, the stamens of which are seen projecting beyond the scale.
22, we recognize four distinct whorls of leaves: an outer whorl, the calyx of sepals; within it, another whorl, the parts alternating with those of the outer whorl, the corolla of petals; next a whorl of parts alternating with the parts of the corolla, the androecium of stamens; and in the centre the gynoecium of carpels.
The outermost series of the essential organs, collectively termed the androecium, is composed of the microsporophylls known as the staminal leaves or stamens.
27), Capparidaceae, and some other plants, the ovary is raised upon a distinct stalk termed the gynophore; it is thus separated from the stamens, and is said to be stipitate.
This arrangement is known as hypogynous, the other series (calyx, corolla and stamens) being beneath (hypo-) the gynoecium.
In many cases this is carried farther and a cavity is formed which is roofed over The flower (stamens and FIG.
s, Sepals; p, petals; a, stamens; c, carpels.
- Monochlamydeous (apetalous) flower of Goosefoot (Chenopodium), consisting of a single perianth (calyx) of five parts, enclosing five stamens, which are opposite the divisions of the perianth, owing to the absence of the petals.
a, Stamens; c, carpels; p, petals; s, sepals.
32, successive stages, a-f, in the transition from petals to stamens.
In some cases, as in the vine-family Ampelidaceae, this seems to be the ordinary mode of development, but the superposition of the stamens on the sepals in many plants, as in the pink family, Caryophyllaceae, is due to the suppression or abortion of the whorl of petals, and this idea is borne out by the development, in some plants of the order, of the suppressed whorl.
Thus, a symmetrical flower may have five sepals, five petals, five stamens and five carpels, or the number of any of these parts may be ten, twenty or some multiple of five.
33 is a diagram of a symmetrical flower of stone-crop, with five sepals, five alternating petals, ten stamens and five carpels.
35 shows a flower of heath, with four divisions of the calyx and corolla, eight stamens in two rows, and four divisions of the pistil.
37 there are three divisions of the calyx, corolla and pistil, and six stamens in two rows.
In Monocotyledons it is usual for the staminal whorl to be double, it rarely having more than two rows, whilst amongst dicotyledons there are often very numerous rows of stamens.
- Diagrammatic section of a symmetrical pentamerous flower of Stone-crop (Sedum), consisting of five sepals (s), five petals (p) alternating with the sepals, ten stamens (a) in two rows, and five carpels (c) containing ovules.
- Diagram of the flower of Flax (Linum), consisting of five sepals (s), five petals (p), five stamens (a), and five carpels (c), each of which is partially divided into two.
The dots represent a whorl of stamens which has disappeared.
The calyx and corolla consist of five parts, the stamens are ten in two rows, while the pistil has only two parts developed.
- Diagram of flower of Sweet-pea (Lathyrus), showing five sepals (s), two superior, one inferior, and two lateral; five petals (p), one superior, two inferior, and two lateral; ten stamens in two rows (a); and one carpel (c).
Thus, in many Caryophyllaceae, as Polycarpon and Holosteum, while the calyx and corolla are pentamerous, there are only three or four stamens and three carpels; in Impatiens Noli-me-tangere the calyx is composed of three parts, while the other verticils have five; in labiate flowers there are five parts of the calyx and corolla, and only four stamens; and in Tropaeolum pentaphyllum there are five sepals, two petals, eight stamens and three carpels.
In the last-mentioned plant the normal number is five, hence it is said that there are three petals suppressed, as shown by the position of the two remaining ones; there are two rows of stamens, in each of which one is wanting; and there are two carpels suppressed.
By the suppression of the verticil of the stamens, or of the carpels, flowers become unisexual or diclinous, and by the suppression of one or both of the floral envelopes, monochlamydeous and achlamydeous flowers are produced.
In the Euphorbiaceae we have an excellent example of the gradual suppression of parts, where from an apetalous, trimerous, staminal flower we pass to one where one of the stamens is suppressed, and then to forms where two of them are wanting.
We next have flowers in which the calyx is suppressed, and its place occupied by one, two or three bracts (so that the flower is, properly speaking, achlamydeous), and only one or two stamens are produced.
There is thus traced a degradation, as it is called, from a flower with three stamens and three divisions of the calyx, to one with a single bract and a single stamen.
In unisexual flowers it is not uncommon to find vestiges of the undeveloped stamens in the form of filiform bodies or scales.
In double flowers transformations of the stamens and pistils take place, so that they appear as petals.
In Canna, what are called petals are in reality metamorphosed stamens.
Thus in Cucurbita the stamens are originally five in number, but subsequently some cohere, so that three stamens only are seen in the mature flower.
Adhesion is well seen in the gynostemium of orchids, where the stamens and stigmas adhere.
In Capparidaceae the calyx and petals occupy their usual position, but the axis is prolonged in the form of a gynophore, to which the stamens are united.
Thus in the horse-chestnut there is an interposition of two stamens, and thus seven stamens are formed in the flower, which is asymmetrical.
Thus in Cruciferous plants the staminal whorl consists of four long stamens and two short ones (tetradynamous).
The symmetry in the flower is evidently dimerous, and the abnormality in the androecium, where the four long stamens are opposite the posterior sepals, takes place by a splitting, at a very early stage of development, of a single outgrowth into two.
Thus in Dicentra and Corydalis there are six stamens in two bundles; the central one of each bundle alone is perfect, the lateral ones have each only half an anther, and are really stipules formed from the staminal leaf.
Branching of stamens also produces apparent want of symmetry; thus, in the so-called polyadelphous stamens of Hypericaceae there are really only five stamens which give off numerous branches, but the basal portion remaining short, the branches have the appearance of separate stamens, and the flower thus seems asymmetrical.
The following is a very simple mode which has been proposed: - The several whorls are represented by the letters S (sepals), P (petals), St (stamens), C (carpels), and a figure marked after each indicates the number of parts in that whorl.
Longitudinal section of flower; v, bracteole on the peduncle; 1, sepals; ls, appendage of sepal; c, petals; cs, spur of the lower petals; fs, glandular appendage of the lower stamens; a, anthers.
s, the whorl of stamens inserted on the thalamus and surrounding the pistil.
Flowers become double by the multiplication of the parts of the corolline whorl; this arises in general from a metamorphosis of the stamens.
55), or on the stamens of Rutaceae.
Other modifications of some part of the flower, especially of the corolla and stamens, are produced either by degeneration or outgrowth, or by chorisis, or deduplication.
In other cases, as in Samolus, the scales are alternate with the petals, and may represent altered stamens.
In Narcissus the appendages are united to form a crown, consisting of a membrane similar to that which unites the stamens in Pancratium.
The stamens and the pistil are sometimes spoken of as the essential organs of the flower, as the presence of both is required in order that perfect seed may be produced.
Hermaphrodite or bisexual flowers are those in which both these organs are found; unisexual or diclinous are those in which only one of these organs appears, - those bearing stamens only, being staminiferous or " male "; those having the pistil only, pistilliferous or " female."
For instance, in Primula and Linum some flowers have long stamens and a pistil with a short style, the others having short stamens and a pistil with a long style.
In some plants the stamens are perfected before the pistil; these are called proterandrous, as in Ranunculus repens, Silene maritima, Zea Mays.
In other plants, but more rarely, the pistil is perfected before the stamens, as in Potentilla argentea, Plantago major, Coix Lachryma, and they are termed proterogynous.
The stamens arise from the thalamus or torus within the petals, with which they generally alternate, forming one or more whorls, which collectively constitute the androecium.
The stamens vary in number from one to many hundreds.
When flowers become double by cultivation, the stamens are converted into petals, as in the paeony, camellia, rose, &c. When there is only one whorl the stamens are usually equal in number to the sepals or petals, and are arranged opposite to the former, and alternate with the latter.
When the stamens are not equal in number to the sepals or petals, the flower is anisostemonous.
When there is more than one whorl of stamens, then the parts of each successive whorl alternate with those of the whorl preceding it.
A flower with a single row of stamens is haplostemonous.
If the stamens are double the sepals or petals as regards number, the flower is diplostemonous; if more than double, polystemonous.
s, Sepals joined to form a gamosepalous calyx; c, corolla consisting of tube and spreading limb; a, stamens springing from the mouth of the tube; p, pistil.
k, Sepal; c, petal; a, stamens; g, pistil.
size.) stamens may be developed in the usual centripetal (acropetal) order, as in Rhamnaceae; or they may be interposed between the pre-existing ones or be placed outside them, i.e.
When the stamens are fewer than twenty they are said to be definite; when above twenty they are indefinite, and are represented by the symbol 00.
The number of stamens is indicated by the Greek numerals prefixed to the term androus; thus a flower with one stamen is monandrous, with two, three, four, five, six or many stamens, di-, tri-, tetr-, pent-, hexor polyandrous, respectively.
The calyx, petals and stamens spring from above the ovary (o) in which two chambers are shown each with a pendulous ovule; d, disc between the stamens and stigmas.
Young stamen is abortive, flower in which the stigma (N) is receptive and cannot perform and the stamens (3) have not yet opened; its functions.
Older flower with the stamens (S) anther is developed o n the c orolla dried up.er(X2) dth e hairs before the filament, and when the latter is not produced, the anther is sessile, as in the mistletoe.
Filaments are usually articulated to the thalamus or torus, and the stamens fall off after fertilization: but in Campanula and some other plants they are continuous with the torus, and the stamens remain persistent, although in a withered state.
Changes are produced in the whorl of stamens by cohesion of the filaments to a greater or less extent, while the anthers remain free; thus, all the filaments of the androecium may unite, forming a tube round the pistil, or a central bundle when the pistil is abortive, the stamens becoming monadelphous, as occurs in plants of the Mallow tribe; or they may be arranged in two bundles, the stamens being diadelphous, as in Polygala, Fumaria and Pea; in this case the bundles may be equal or unequal.
When there are three or more bundles the stamens are triadelphous, as in Hypericum aegyptiacum, or polyadelphous, as in Ricinus communis (castor-oil).
In some cases, as in papilionaceous flowers, the stamens cohere, having been originally separate, but in most cases each bundle is produced by the branching of a single stamen.
When there are three stamens in a bundle we may conceive the lateral ones as of a stipulary nature.
In Lauraceae there are perfect stamens, each having at the base of the filament two abortive stamens or staminodes, which may be analogous to stipules.
- Stamens and pistil of Sweet Pea (Lathyrus).
The stamens are diadelphous, nine of them being united by their filaments (f), while one of them (e) is free; st, stigma; c, calyx.
The stamens may cohere by their anthers, and become syngenesious, as in composite flowers, and in lobelia, jasione, &c.
In the latter case individual stamens may move in succession towards the pistil and discharge their contents, as in Parnassia palustris, or the outer or the inner stamens may first dehisce, following thus a centripetal or centrifugal order.
Stamens occasionally become sterile by the degeneration or non-development of the anthers, when they are known as staminodia, or rudimentary stamens.
In other cases, as in double flowers, the stamens are converted into petals; this is also probably the case with such FIG.
- Two stamens of Pansy (Viola tricolor), with their two anther-lobes and the connectives (p) extending beyond them.
One of the stamens has been deprived of its spur, the other shows its spur c. FIG.
Stamens vary in length as regards the corolla.
Sometimes the stamens in the early state of the flower project beyond the petals, and in the progress of growth become included, as in Geranium striatum.
Stamens also vary in their relative lengths.
When the stamens are in two rows, those opposite the petals are usually shorter than those which alternate with the petals.
number, sometimes exists between the long and the short stamens.
Thus, in some flowers the stamens are didynamous, having only four out of five stamens developed, and the two corresponding to the upper part of the flower longer than the two lateral ones.
Stamens, as regards their direction, may be erect, turned inwards, outwards, or to one side.
The term clinandrium is sometimes applied to the part of the column in orchids where the stamens are situated.
- Corolla of foxglove (Digitalis purpurea), cut in order to show the didynamous stamens (two long and two short) which are attached to it.
- Tetradynamous stamens (four long and two short) of wallflower (Cheiranthus Cheiri).
- Male flower of Pellitory (Parietaria officinalis), having four stamens with incurved elastic filaments, and an abortive pistil in the centre.
Under the term disk is included every structure intervening between the stamens and the pistil.
It may consist of processes rising from the torus, alternating with the stamens, and thus representing an abortive whorl; or its parts may be opposite to the stamens.
In some flowers, as Jatropha Curcas, in which the stamens are not developed, their place is occupied by glandular bodies forming the disk.
In Gesneraceae and Cruciferae the disk consists of toothlike scales at the base of the stamens.
The pistil or gynoecium occupies the centre or apex of the flower, and is surrounded by the stamens and floral envelopes when these are present.
The stamens are indefinite, and are inserted below the pistil (hypogynous).
The stamens (c) have withered.
x, Receptacle with the points of insertion of the stamens a, most of which have been removed.
2 2) the pistil consists of five verticillate carpels o, alternating with the stamens e.
- Flower of a grass with glumes removed, showing three stamens and two feathery styles.
- A, Male catkin in longitudinal section: a, axis; b, bracts; c, d, filaments of stamens, bearing the pollen-sacs (e and f) at the top; v, apex of axis.
(x 6z.) B, Stamens more highly magnified: g, vascular bundle of filament; e, pollen-sac after dehiscence.
Some of the stamens are inserted between the bracts, in an apparently axillary position, while others are grouped about the apex of the axis.
The stamens are probably best compared with those of Ginkgo, but they have also been interpreted as corresponding to the male " flowers " of the Gnetaceae.
true Coniferae, though some resemblance to the stamens of Araucarieae may be traced.
size.) characterized by a rather larger number of oval pollen-sacs on the stamens, have been found in England, Germany, Siberia and elsewhere in association with Ginkgo and Baiera foliage.
The occasional occurrence of three or even four pollen-sacs on the stamens of the recent species affords a still closer agreement between the extinct and living types.
small persistent, 5-dentate calyx, 5 petals, 1 0 stamens, a sessile 3 to 5-chambered ovary, a long style, and a 3-lobed stigma; fruit trigonal or pentagonal; and seed compressed.
Spring squill has blue anthers, these are the parts on the ends of the stamens which carry the pollen grains.
They carry generous clusters of gleaming flowers, with sleek scarlet sepals flaring to reveal a slim skirt of purple petals surrounding coral stamens.
There are about 20 stamens, white with an orange head, clustered around a central green pistil with a yellow head.
Each flower has six stamens and a single pistil.
They always have many male stamens, which produce pollen.
Fragrant, orange flowers with prominent dark stamens are borne in dense terminal spikes up to 25cm long.
Exquisite in bud, they open fully to reveal a central boss of golden stamens.
Middle image - the male flowers carrying a cluster of long stamens.
The many yellow stamens are the most conspicuous feature of the flowers, varying in shade from bright to very pale.
Hedychium coccineum ' Tara ' has large spikes of dense, fragrant, orange trumpet-shaped flowers with prominent darker orange stamens.
stamens in the red flowers appeared to have shed their pollen.
stamens in two groups, sensitive; Plants self sterile.
stamens of the male tree flowers.
subfamilyily has been classified into two subfamilies based on the structure of the stamens and ovaries.
These are aquatic plants with thick fleshy rootstocks or tubers embedded in the mud, and throwing up to the surface circular shield-like leaves, and leafless flower-stalks, each terminated by a single flower, often of great beauty, and consisting of four or five sepals, and numerous petals gradually passing into the very numerous stamens without any definite line of demarcation between them.
The catkins of the poplars differ from those of the nearly allied willows in the presence of a rudimentary perianth, of obliquely cup-shaped form, within the toothed bracteal scales; the male flowers contain from eight to thirty stamens; the fertile bear a onecelled (nearly divided) ovary, surmounted by the deeply cleft stigmas; the two-valved capsule contains several seeds, each furnished with a long tuft of silky or cotton-like hairs.
The sporophylls (stamens and carpels) are generally associated with other leaves, known as the perianth, to form a flower; these subsidiary leaves are protective and attractive in function and their development is correlated with the transport of pollen by insect agency (see ANGI0sPERM5; POLLINATION, and FLOWER).
Similar views were arrived at by Goethe, though by the deductive rather than the inductive method, and were propounded in his famous pamphlet, Versuch die Metamorphose der Pfianzen zu erklren (1790), from which the following is a quotation: The underlying relationship between the various external parts of the plant, such as the leaves, the calyx, the corolla, the stamens, which develop one after the other and, as it were, out of one another has long been generally recognized by investigators, and has iii fact been specially studied; and the operation by which onc and the same organ presents itself to us in various forms has been termed Metamorphosis of Plants.
Recent researches, however, more especially those of Celakovsky, tend to prove that the perianth-leaves have been derived from the stamens (i.e.
A simple case is that of double flowers, in which the number of the petals is increased by the metamorphosis of stamens; or again the conversion of floral leaves into green leaves, a change known as chloranthy.
There is a very wide range in the general structure and arrangement of the parts of the flower, associated with the means for ensuring the transference of pollen; in the simplest cases the flower consists only of a few stamens or carpels, with no enveloping sepals or petals, as in the willow, while in, the more elaborate type each series is represented, the whole forming a complicated structure closely correlated with the size, form and habits of the pollinating agent (see Flower).
5), the perianth which is generally petaloid occupying the two outer whorls, followed by two whorls of stamens, with a superior ovary of three carpels in the centre of the flower; the ovary is generally three-chambered and contains an indefinite number of anatropous ovules on axile placentas (see fig.
The cultivated vine has usually hermaphrodite flowers; but as it occurs in a wild state, or as an escape from cultivation, the flowers manifest a tendency towards unisexuality: that is, one plant bears flowers with stamens only, or only the rudiments of the pistil, while on another plant the flowers are bisexual.
The larger-flowered species of Geranium are markedly protandrous, the outer stamens, inner stamens and stigmas becoming.
There is in some genera (Oryza, most Bambuseae) another row of three stamens, making six in all (fig.
disposed stamens; each stamen consists of a slender Flowers filament terminating in a small apical scale, which bears usually two, but not infrequently three or four pollen-sacs (fig.
Again, in the passion-flower (Passiflora) the stamens are separated from the corolla by an elongated portion of the axis, which has consequently been termed the andro phone, and in Passiflora also, fraxinella (fig.
Where the stamens become adherent to the pistil so as to form a column, the flowers are said to be gynandrous, as in Aristolochia (fig.
In acyclic flowers there is often a gradual transition from petals to stamens, as in the white water-lily (fig.
It frequently happens, especially in Papilionaceous flowers, that out of ten stamens nine are united by their filaments, while one (the postericr one) is free (fig.
Again, in other cases there are six stamens, whereof four long ones are arranged in pairs opposite to each other, and alternate with two isolated short ones (fig.
When the ovary is situated on the centre of the receptacle, free from the other whorls, so that its base is above the insertion of the stamens, it is termed superior, as in Lychnis, Primula (fig.
However, they also noticed that the turned down stamens in the red flowers appeared to have shed their pollen.
Flower medium sized to large with funnel shaped receptacle, petals yellow; stamens in two groups, sensitive; Plants self sterile.
Look closely and you might just be able to see pollen at the tips of the stamens of the male tree flowers.
The family has been classified into two subfamilies based on the structure of the stamens and ovaries.
Inside a pair of white bracts about the size of the hand is a head of redanthered stamens, and a tree in full flower is a marvellous sight, owing to the alternate white and green caused by the large bracts intermingling with the leaves.
The blossoms, at their best in September, are carried as erect spikes of about 4 inches, each spike holding about a score of small ivory-white flowers with reflexing petals and protruding stamens.
T. unifoliata, with white flowers and rosy stamens, is also good.
Trollius Ledebouri - A valuable late-flowering species with rich orange flowers and conspicuously protruding stamens.
Its leaves are Plum-like and shining, with saw-like edges, and the flowers pure white, fragrant, with prominent yellow-tipped stamens.
In H. breviscapa they are 6 to 8 inches long, white with deep lilac stamens, the whole turning a pretty rose-red before fading.
Meconopsis Aculeata - A singularly beautiful plant, with purple petals, like shot silk, which contrast charmingly with the numerous yellow stamens.
The nodding flowers come during summer upon hairy stems of 6 to 12 inches, and are cup-shaped, 1 1/2 inches wide, and pale violet or purple with a large cluster of golden stamens.
It differs in having ten stamens to each flower.
Nymphaea Alba Odorata Rosacea--A - od form coming near exquisita but more vigorous, with bright rosy flowers about 4 inches across, paling to salmon-yellow towards the crown of golden stamens; petals narrow and pointed.
Lyalli, with woolly leaves of a long heart-shape and large pure white flowers with a bunch of golden stamens, drooping gracefully in clusters upon long stems from the tips of the previous seasons growth.
Usually about 2 feet high, they have large white flower 4 inches across, with a bunch of yellow stamens in the centre.
A feature of the flower also is the long stamens.
Fuchsioides. Its deep red blooms have protruding stamens, and hang from the leaf-axils in clusters of two or three.
The flowers are large and beautiful, chiefly white, but flesh-tinted round the edges and in the centre with a tuft of fine yellow stamens.
The flower-heads are moderately dense, and the flowers are bright red, excepting those at the lower end of the head, which are bright yellow, the style protruding, the stamens being included in the tube.
Kniphofia Foliosa - Almost the counterpart of K. caulescens, but it has distinct stems, being also one of the most robust of all the Kniphofias, and easily distinguished by its broadish leaves and its protruding stamens.
Kniphofia Rooperi - Nearly allied to K. aloides, but is an early or summer-flowering plant, while the stamens are included in the tube; the flowers are paler and less curved, and the leaves are broad and very glaucous.
Nymphaea Alba Atropurpurea - One of the darkest of all, with very large flowers of deep port-wine color, with pale yellow stamens and petals incurved at the tips.
Nymphaea Alba Chrysantha - A handsome kind of medium growth, and deep yellow flowers passing to orange-red, with a cluster of bright red stamens; leaves edged and marbled with bronze.
Leaves rich green above and brown beneath, the fragrant flowers of pale pink, the outer segments of pale olive-green, and pale yellow stamens.
Large broad-petalled flowers of reddish-crimson with orange-red stamens.
Of good size and fragrant, its flowers are of deep crimson with orange stamens, coming freely to the end of September.
Its color is rose upon yellow, with yellow stamens, the red growing deeper towards the centre and brightening with age.
Nymphaea Alba Gloriosa - Bears massive flowers 7 inches across, rich dark red with orange-colored stamens, and fragrant.
Nymphaea Alba James Brydon - A distinct sort with flowers of 4 to 6 inches wide, of a soft rose-crimson; petals finely rounded and curving inwards, with a paler, silvery sheen beneath, and stamens of bright orange.
Nymphaea Alba Laydekeri Fulgens - A flower of fine color and cupped, the rounded petals of crimson-purple showing paler within and enclosing a cluster of vivid red stamens.
They are early, free, and fragrant, of a conspicuous shade of wine-red with orange-red stamens.
Nymphaea Alba Lucida - With massive flowers opening starwise and rosy-vermilion in color, paling towards the edges and the tips of the petals and deepening towards the cluster of orange stamens.
Flammea - A handsome, though inaptly named, flower of medium size, being a deep wine-red rather than flame-color, with red stamens and petals flaked with white towards the tips.
Ignea - One of the brightest in its uniform carmine-red, deepening slightly towards the crown of vivid orange-red stamens; sepals pale olive-green edged with rose beneath, and paler above.
Petals rosy-purple, tipped and flaked with pink; stamens orange-red.
Nymphaea Alba Odorata Exquisita - Finely-shaped rosy-carmine flowers of medium size, with narrow, pointed petals and golden stamens; they are the darkest of this group, and stand well out of the water.
Nymphaea Alba Odorata Rosea - The Cape Cod Water-Lily-a plant of moderate vigour, with petals of a uniform bright rose color with yellow stamens, and fragrant.
The petals are pointed and sprinkled with red about the edges, the stamens deep yellow.
It is nearly as vigorous as its parent, with large pink flowers rising above the water, and opening widely to show the crown of bright red stamens.
It blossoms in spring, the inflorescence having a bottle-brush appearance owing to the length of the white stamens, which, petals being absent, form the only conspicuous part of the flowers.
The six petal blossom with a multitude of bright yellow stamens is a pleasure to see amid the drab winter landscape of most gardens.
More specifically, it is entomophile pollen; male seed from the stamens of flowers.
For example, imagine parting the petals of a lily into four butterfly wings, and creating the butterfly body and antennae from the pollen stamens.
axillary or terminal spikes; they have four stamens, which bear at the back four small herbaceous petal-like structures, and four free carpels, which ripen to form four small green fleshy fruits, each containing one seed within a hard inner coat;.
The male flowers are in small clusters on the usually slender and pendent stalk, forming an interrupted catkin; the stamens vary in number, usually six to twelve.
These occur on the tips of tendrils and on the tentacles of Drosera; (2) sensitive papillae found on the irritable filaments of certain stamens; and (3) sensitive hairs or bristles on the leaves of Dionaea muscipula and Mimosa pudicaall of which are so constructed that any pressure exerted on them at once reacts on the protoplasm.
Thus, in a phanerogam, the sepals, petals, stamens and foliage-leaves all come under the category leaf, though some are parts of the perianth, others are spore-bearing organs (sporophylls), and others carry on nutritive processes.
It has pale-purple flowers, rarely more than three in number; the perianth is funnel-shaped, and produced below into a long slender tube, in the upper part of which the six stamens are inserted.
The parts of the flower are most frequently arranged in fives, or multiples of fives; for instance, a common arrangement is as follows, - five sepals, succeeded by five petals, ten stamens in two sets of five, and five or fewer carpels; an arrangement in fours is less frequent, while the arrangement in threes, so common in monocotyledons, is rare in dicotyledons.
Within the perianth, and springing from its sides, or apparently from the top of the ovary, are six stamens whose anthers contain pulverulent pollen-grains.
These stamens encircle a style which is the upward continuation of the ovary, and which shows at its free end traces of the three originally separate but now blended carpels of which the ovary consists.
described, but with the ovules on the walls of the cavity (not in its axis or centre), a six-parted perianth, a stamen or stamens and stigmas.
In place of the six stamens we commonly find but one (two in Cypripedium), and that one is raised together with the stigmatic surfaces on an elongation of the floral axis known as the "column."
It would appear, then, that the orchid flower differs from the more general monocotyledonous type in the irregularity of the perianth, in the suppression of five out of six stamens, and in the union of the one stamen and the stigmas.
The order is divided into two main groups based on the number of the stamens and stigmas.
The first Diandreae, has two or rarely three fertile stamens and three functional stigmas.
and Sambucus, more rarely two-lipped as in Lonicera; the sepals and petals are usually five in number and placed above the ovary, the five stamens are attached to the corolla-tube, there are three to five carpels, and the fruit is a berry as in honeysuckle or snowberry (Symphoricarpus), or a stone fruit, with several, usually three, stones, as in Sambucus.
To preserve the colour of flowers pledgets of cotton wool, which prevent bruising, should be introduced between them, as also, if the stamens are thick and succulent, as in Digitalis, between these and the corolla.
Owing, however, to the close proximity of stigma and anthers, very slight irregularity in the movements of the visiting insect will cause self-pollination, which may also occur by the dropping of pollen from the anthers of the larger stamens on to the stigma.
The word usage examples above have been gathered from various sources to reflect current and historial usage. They do not represent the opinions of YourDictionary.com.