At other times the slit is horizontal, from the connective to the - side, as in Alchemilla arvensis fig. 73 and in Lemna; the dehiscence is then the anther lobes are rendered horizontal by the enlargement of the connective, then what is really longitudinal dehiscence may appear to be cleft does not always proceed the whole length of the anther-lobe at once, but often for a time it extends only other instances the opening is confined to the base or apex, each loculament opening by a single pore, as in Pyrola, Tetratheca juncea, Rhododendron, Vaccinium and Solanum fig.

74, where there are two, and Poranthera, where there are four; whilst in the mistletoe the anther has numerous pores for the discharge of the mode of dehiscence is the valvular, as in the barberry fig. 75, where each lobe opens by a valve on the outer side of the suture, separately rolling up from base to apex; in some of the laurel tribe there are two such valves for each lobe, or four in some Guttiferae, as Hebradendron cambogioides the Ceylon gamboge plant, the anther opens by a lid separating from the apex circumscissile dehiscence.

article The anthers dehisce at different periods during the process of flowering; sometimes in the bud, but more commonly when the pistil is fully developed and the flower is either dehisce simultaneously or 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 variations are intimately connected with the arrangements for transference of anthers are called introrse when they dehisce by the surface next to the centre of the flower; they are extrorse when they dehisce by the outer surface; when they dehisce by the sides, as in Iris and some grasses, they are laterally dehiscent.

Sometimes, from their versatile nature, anthers originally introrse become extrorse, as in the Passionflower and Oxalis. The usual colour of anthers is yellow, but they present a great variety in this are red in the peach, dark purple in the poppy and tulip, orange in Eschscholtzia, c. The colour and appearance of the anthers often change after they have discharged their functions.

article Stamens occasionally become sterile by the degeneration or non-development of the anthers, when they are known as staminodia, or rudimentary Scrophularia the fifth stamen appears in the form of a scale; and in many Pentstemons it is reduced to a filament with hairs or a shrivelled membrane at the 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 of the stamens has been deprived of its spur, the other shows its spur c.

lf, fertile lobe full of pollen; ls, barren lobe without pollen; e, connective; f, filament. - Stamen of a species of Nightshade Solanum, showing the divergence of the anther-lobes at the base, and the dehiscence by pores at the apex.

- The stamen of the Barberry Berberis vulgaris, showing one of the valves of the anther v curved upwards, bearing the pollen on its inner surface. plants as Mesembryanthemum, where there is a multiplication of petals in several rows. Sometimes, as in Canna, one of the anther-lobes becomes abortive, and a petaloid appendage is vary in length as regards the are enclosed within the tube of the flower, as in Cinchona included; others are exserted, or extend beyond the flower, as in Littorella or the stamens in the early state of the flower project beyond the petals, and in the progress of growth become included, as in Geranium also vary in their relative there is more than one row or whorl in a flower, those on the outside are sometimes longest, as in many Rosaceae; at other times those in the interior are longest, as in the stamens are in two rows, those opposite the petals are usually shorter than those which alternate with the sometimes happens that a single stamen is longer than all the rest.

A definite relation, as regards I. 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 occurs in Labiatae and Scrophulariaceae 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. 77, giving rise to tetradynamous flowers, as in Cruciferae. Stamens, as regards their direction, may be erect, turned inwards, outwards, or to one the last-mentioned case they are called declinate, as in amaryllis, horse-chestnut and fraxinella.

article The pollen-grains or microspores contained in the anther consist of small cells, which are developed in the large thick-walled mother-cells formed in the interior of the pollen-sacs microsporangia of the young mother-cells are either separated from one another and float in the granular fluid which fills up the cavity of the pollen-sac, or are not so isolated.

A division takes place, by which four cells are formed in each, the exact mode of division differing in dicotyledons and cells are the increase in size and acquire a cell-wall, which becomes differentiated into an outer cuticular layer, or extine, and an inner layer, or intine. Then the walls of the mother-cells are absorbed, and the pollengrains float freely in the fluid of the pollen-sacs, which gradually disappears, and the mature grains form a powdery mass within the then either remain united in fours, or multiples of four, as in some acacias, Periploca graeca and Inga anomala, or separate into individual grains, which by degrees become mature pollen.

Occasionally the membrane of the mother-cell is not completely absorbed, and traces of it are detected in a viscid matter surrounding the pollen-grains, as in orchidaceous plants the pollen-grains are united into masses, or pollinia fig.

78, by means of viscid orchids each of the pollen-masses has a prolongation or stalk caudicle which adheres to a prolongation at the base of the anther rostellum by means of a viscid gland retinaculum which is either naked or term clinandrium is sometimes applied to the part of the column in orchids where the stamens are some orchids, as Cypripedium, the pollen has its ordinary character of separate number of pollinia varies; thus, in Orchis there are usually two, in Cattleya four, and in Laelia two pollinia in Orchis Morio contain each about 200 secondary smaller small masses, when bruised, divide into grains which are united in Asclepiadaceae the pollinia are usually united in pairs fig.

79, belonging to two contiguous anther-lobes - each pollen-mass having a FIG. article - Pollinia, or pollen-masses, with their retinacula same day flower delivery tampa fl or viscid matter attaching them at the pollen masses p are supported on stalks or caudicles c.

These masses are easily detached by the agency of enlarged. caudicular appendage, ending in a common gland, by means of which they are attached to a process of the pollinia are also provided with an appendicular staminal covering fig. The extine is a firm membrane, which defines the figure of the pollen-grain, and gives colour to it.

It is either smooth, or covered with numerous projections fig. 81, granules, points or crested colour is generally yellow, and the surface is often covered with a viscid or oily intine is uniform in different kinds of pollen, thin and transparent, and possesses great power of some aquatics, as Zostera, Zannichellia, Naias, c. Pollen-grains vary from a o 0 - to o-y of an inch or less in forms are most common form of grain is ellipsoidal, more or less narrow at the extremities, which are called its poles, in contradistinction to a line equidistant from the extremities, which is its equator.

Pollen-grains are also spherical; cylindrical and curved, as in Tradescantia virginica; C From Vines Students Text-Book of Botany, by permission of Swan Sonnenschein Co. article - Germinating pollengrain of Epilobium highly mag. bearing a pollen-tube s; e, exine; intine; abc, the three spots where the exine is thicker in anticipation of the formation of the pollen-tube developed in this case at a. polyhedral in Dipsacaceae and Compositae; nearly triangular in section in Proteaceae and Onagraceae fig.

The surface of the pollen-grain is either uniform and homogeneous, or it is marked by folds formed by thinnings of the are also rounded portions of the membrane or pores visible in the pollengrain; these vary in number from one to fifty, and through one FIG. - Corolla of foxglove Digitalis purpurea, cut in order to show the didynamous stamens two long and two short which are attached to it.

- Male flower of Pellitory Parietaria officinalis, having four stamens with incurved elastic filaments, and an abortive pistil in the the perianth p expands, the filaments are thrown out with force as at a, so as to scatter the pollen. When the pollen-grains are ripe, the anther dehisces and the pollen is order that fertilization may be effected the pollen must be conveyed to the stigma of the pistil.

article Polling- Thisrocess termed pollination see Pollination. p p is promoted in various ways, the whole form and structure of the flower having relation to the some plants, as Kalmia and Pellitory fig.

83, the mere elasticity of the filaments is sufficient to effect this; in other plants pollination is effected by the wind, as in most of our forest trees, grasses, c.and in such cases enormous quantities of pollen are plants are anemophilous. But the common agents for pollination are allure and attract them to visit the flower the odoriferous secretions and gay colours are developed, and the position and complicated structure of the parts of the flower are adapted to the perfect performance of the process, It is comparatively rare in hermaphrodite flowers for self-fertilization to occur, and the various forms of dichogamy, dimorphism and trimorphism are fitted to prevent this.

Under the term disk is included every structure intervening between the stamens and the was to such the name of nectary was applied by old authors. article It presents great varieties of form, such as a ring, scales, glands, hairs, petaloid appendages, c.and in the progress of growth it often contains saccharine matter, thus becoming truly disk is frequently formed by degeneration or transformation of the staminal 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 some flowers, as Jatropha Curcas, in which the stamens are not developed, their place is occupied by glandular bodies forming the Gesneraceae and Cruciferae the disk consists of toothlike scales at the base of the parts composing the disk sometimes unite and form a glandular ring, as in the orange; or they form a dark-red lamina covering the pistil, as in Paeonia Moutan fig.

- Flower of Tree waxy lining of the hollow receptacle, Paeony Paeonia Moutan, as in the rose; or a swelling at the deprived of its corolla, and top of the ovary, as in Umbelliferae, showing the disk in the form in which the disk is said to be of a fleshy expansion d ep i enlarged torus covering the ovary. article When a pistil consists of a single carpel it is simple or monocarpellary fig.

When it is composed of several carpels, more or less united, it is compound or polycarpellary fig. - Vertical section of the flower of Black Hellebore Helleborus niger. - Fruit of the Strawberry Fragaria vesca, consisting of an enlarged succulent receptacle, bearing on its surface the small dry seed-like fruits achenes.

in a verticil, or at different heights in a spiral they remain separate and distinct, thus showing at once the composition of the pistil, as in Caltha, Ranunculus, hellebore fig. 86, and Spiraea, the term apocarpous is applied. 2 2 the pistil consists of five verticillate carpels o, alternating with the stamens e.

89 the separate carpels are numerous and are arranged in a spiral cycle upon an elongated axis or the raspberry the carpels are on a conical receptacle; in the strawberry, on a swollen succulent one fig.

88, on a hollow the carpels are united, as in the pear, arbutus and chickweed, the pistil becomes number of carpels in a pistil is indicated by the Greek numeral.