§ 12. The Receptacle and Relative Attachment of the Floral Whorls.
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135. The Receptacle or torus is the extremity of the peduncle (above the calyx) upon which the corolla, stamens, and ovary are inserted. It is sometimes little more than a mere point or minute hemisphere, but it is often also more or less elongated, thickened or otherwise enlarged. It must not be confound with the receptacle of inflorescence (74).
136. A Disk, or disc, is a circular enlargement of the receptacle, usually in the form of a cup (cupular), or a flat disk or quoit, or of a cushion (pulvinate). It is either immediately at the base of the ovary within the stamens, or between the petals and stamens, or bears the petals or stamens or both on its margin, or is quite at the extremity of the receptacle, with the ovaries arranged in a ring round it or under it.
137. The disk may be entire, or toothed, or lobed, or divided into a number of parts, usually equal to, or twice that of the stamens or carpels. When the parts of the disk are quite separate and short, they are often called glands.
138. Nectaries are either the disk, or small deformed petals, or abortive stamens, or appendages at the base of petals, or stamens, or any small bodies within the flower which do not like petals, stamens, or ovaries. They were formerly supposed to supply bees with their honey, and the term is frequently to be met with in the older Floras, but is now deservedly going out of use.
139. When the disk bears the petals and stamens, it is frequently adherent to, and apparently forms part of, the tube of the calyx, or it is adherent to, and apparently forms part of, the ovary, of both the calyx-tube and ovary. Hence the three following important distinctions in the relative insertion of the floral whorls.
140. Petals, or as it is frequently expressed, flowers, are
hypogynous (i.e., under the ovary), when they or the disk that bears them are entirely free both from the calyx and ovary. The ovary is then described as free or superior, the calyx as free or inferior, the petals as being inserted on the receptacle.
perigynous (i.e., round the ovary), when the disk bearing the petals is quite free from the ovary, but is more or less combined with the base of the calyx-tube. The ovary is then still described as free or superior, even though the combined disk and calyx-tube may form a deep cup with the ovary lying in the botton; the calyx is said to be free or inferior, and the petals are described as inserted on the calyx.
epigynous (i.e., upon the ovary, when the disk bearing the petals is combined both with the base of the calyx tube and the base outside the ovary; either closing over the ovary so as only to leave a passage for the style, or leaving more or less the top of the ovary free, but always adhering to it above the level of the insertion of the lowest ovule (except in a very few cases where the ovules are absolutely suspended from the top of the cell). In epigynous flowers the ovary is described as adherent or inferior, the calyx as adherent or superior, the petals as inserted on or above the ovary. In some works, however, most epigynous flowers are included in the perigynous ones, and a very different meaning is given to the term epigynous (144), and there are a few cases where no positive distinction can be drawn between the epigynous and perigynous flowers, or again between the perigynous and hypogynous flowers.
141. When there are no petals, it is the insertion of the stamens that determines the difference between the hypogynouis, perigynous and epigynous flowers.
142. When there are both petals and stamens
in hypogynous flowers, the petals and stamens are usually free from each other, but sometimes combined at the base. In the case if the petals are distinct from each other, and the stamens are monodelphous, the petals are said to be inserted on or combined with the staminal tube; if the corolla is gamopetalous and the stamens distinct from each other, the latter as latter as said to be inserted in the tube of the corolla
in perigynous flowers, the stamens are usually inserted immediately within the petals, or alternating with them on the edge of the disk, but occasionally much lower down the disk, or even on the unenlarged part of the receptacle.
in epigynous flowers, when the petals are distinct, the stamens are usually inserted as in perigynous flowers; when the corolla is gamopetalous, the stamens are either free and epigynous, or combined at the base with (inserted in) the tube of the corolla.
143. When the receptacle is distinctly elongated below the ovary, it is often call a gynobasis, gynophore, or stalk of the ovary. If the elongation takes place below the stamens of below the petals, these petals are then said to be inserted on the stalk of the ovary; and are occasionally, but falsely, described as epigynous. Really epigynous stamens (i.e., when the filaments are combined with the ovary) are very rare, unless the rest of the flower is epigynous.
144. An epigynous disk is a name given either to the thickened summit of the ovary in epigynous flowers, or very rarely to a real disk or enlargment of the receptacle closing over the ovary.
145. In the relative position of any two or more parts of the flower, whether in the same or different whorls, they are
connivent, when nearer together at the summit than at the base.
divergent, when further apart at the summer than at the base.
coherent, when united together, but so slightly that they can be separated with little or not laceration; and one of the two coherent parts (usually the smallest or least important) is said to be adherent to the other. Grammatically speaking, these two terms convey nearly the same meaning, but require a different form of phrase; practically it has been found more convenient to restrict cohesion to the union of parts of the same whorl, and adhesion to the union of parts of different whorls.
connate, when so closely united that they cannot be separated without laceration. Each of the two connate parts, and especially the one which is considered the smaller or of the least importance, is said to adnate to the other.
free, when neither coherent nor connate.
distinct is also used in the same sense, but is also applied to parts distinctly visible or distinctly limited.
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