§ 9. The Calyx and Corolla, or Perianth.
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96. The Calyx (90) is usually green, and smaller than the corolla; sometimes very minute, rudimentary, or wanting, sometimes very indistinctly whorled, or not whorled at all, or in two whorls, or composed of a large number of sepals, of which the other ones pass gradually into bracts, and the inner ones into petals.
97. The Corolla is usually coloured, and of a more delicate texture than the calyx, and in popular language, is often more specially meant by the flower. Its petals are more rarely in two whorls, or indefinite in number, and the whorl more rarely broken than in the case of the calyx, at least when the plant is in a natural state. Double flowers are in most cases an accidental deformity or monster in which the ordinary number of petals is multiplied by the conversion of stamens, sepals, or even carpels into petals, by the division of ordinary petals, or simply by the addition of supernumerary ones. Petals are sometimes very small, rudimentary, or entirely deficient.
98. In very many cases, a so-called simple perianth (15) (of which the parts are usually called leaves or segments) is one in which the sepals and petals are similar in form and texture, and present apparently a single whorl. But if examined in the young bud, one half of the parts will generally be found to be placed outside the other half, and there will frequently be some slight difference in texture, size, and colour indicating to the close observer the presence of both calyx and corolla. Hence much discrepancy in descriptive works. Where one botanist describes a simple perianth of six segments, another will speak of a double perianth of three sepals and three petals.
99. The following terms and prefixed, expressive of the modifications of form and arrangement of the corolla and its petals, are equally applicable to the calyx and its sepals, and to the simple perianth and its segments.
100. The Corolla is said to be monopetalous when the petals are united, either entirely or at the base only, into a cup, tube, or ring; polypetalous when the are all free from the base. These expressions, established by a long usage, are not strictly correct, for monopetalous (consisting of a single petal) should apply to a corolla really reduce to a single petal, which would then be on one side of the axis; and polypetalous is sometimes used more appropriately for a corolla with an indefinite number of petals. Some modern botanists have therefore proposed the term gamosepalous for the corolla with united petals, and dialypetalous for that with free petals; but the old established expressions are still the most used.
101. When the petals are partially united, the lower entire portion of the corolla is called the tube, whatever be its shape, and the free portions of the petals are called the teeth, lobes, or segments (39), according as they are short or long in proportion to the whole length of the corolla. When the tube is excessively short, the petals appear at first sight free, but their slight union at the base must be carefully attended to, being of importance in classification.
102. The Æstivation of a corolla is the arrangement of the petals, or of such portion of them as is free, in the unexpanded bud. It is
valvate, when they are strictly whorled in their whole length, their edges being placed against each other without overlapping. If the edges are much inflexed, the aestivation is at the same time induplicate; involute, if the margins are rolled inward; reduplicate, if the margins project outwards into salient angles; revolute, if the margins are rolled outwards; plicate, if the petals are folded in longitudinal plaits.
imbricate, when the whorl is more or less broken by some of the petals being outside the others, or by their overlapping each other at least at the top. Five-petalled imbricate corollas are quincuncially imbricate when one petal is outside, and an adjoining one wholly inside, the three others intermediate and overlapping on one side; bilabiate, when two adjoining ones are inside or outside the three others. Imbricate petals are described as crumpled (corrugate) when puckered irregularly in the bud.
twisted, contorted, or convolute, when each petal overlaps an adjoining one on one side, and is overlapped by the other one on the other side. Some botanists include the twisted æstivation in the general term imbricate; others carefully distinguish theone from the other.
103. In a few cases the overlapping is so slight that the three æstivations cannot be easily distinguished one from the other; in a few others the æstivation is variable, even in the same species, but, in general, it supplies as constant character in species, in genera, or even Natural Orders.
104. In general shape the Corolla is
tubular, when the whole or greater part of it is in the form of a tube or cylinder.
campanulate, when approaching in some measure the shape of a cup or bell.
urceolate, when the tube is swollen or nearly globular, contracted at the top, and slightly expanded in a narrow rim.
rotate or stellate, when the petals or lobes are spread out horizontally form the base, or nearly so, like a wheel or star.
hypocrateriform or salver-shaped, when the lower part is cylindrical and the upper part expanded horizontally. In this case the name of tube is restricted to the cylindrical part, and the horizontal portion is called the limb, whether it be divided to the base or not. The orifice of the tube is called its mount or throat.
infundibuliform or funnel-shaped, when the tube is cylindrical at the base, but enlarged at the top into a more or less campanulate limb, of which the lobes often spread horizontally. In this case the campanulate part, up to the commencement of the lobes, is sometimes considered as a portion of the tube, sometimes as a portion of the tube, sometimes as a portion of the limb, and by some botanist again as independent of either, under the name of throat (faucex). Generally speaking, however, in campanulate, infundibuliform, or other corollas, where the lower entire portion passes gradually into the upper divided and more spreading part, the distinction between the tube and the limb is drawn either at the point where the lobes separate, or at the part where the corolla first expands, according to which is the most marked.
105. Irregular corollas have received various names according to the more familiar forms they have been compared to. Some of the most important are the
bilabiate, or two-lipped corolla, when, in a four- or five-lobed corolla, the two or three upper lobes stand obviously apart, like an upper lip, from the two or three lower ones, or under lip. In Orchideæ and some other families the name of lip, or labellum, is given to one of the divisions or lobes of the perianth.
personate, when two-lipped, and the orifice of the tube closed by a projection from the base of the upper or lower lip, called a palate.
ringent, when very widely two-lipped, and the orifice of the tube very open.
spurred, when the tube or the lower part of a petal has a conical hollow projection, compared to the spur of a cock; saccate when the spur is short and round like a little bag; gibbous, when projecting at any part into a slight swelling; faveolate, when marked in any part with a slight glandular or thickened cavity.
resupinate or reversed, when a lip, spur, etc., which is in allied species is usually lowest, lies uppermost, or vice versâ.
106. The above terms are mostly applied to the forms of monopetalous corollas, but several are also applicable to those of polypetalous ones. Terms descriptive of the special forms of corolla in certain Natural Orders will be explained under those Orders respectively.
107. Most of the terms used for describing the forms of leaves (39, 45) are also applicable to those of individual petals, but the flat expanded portion of a petal, corresponding to the blade of the leaf, is called its lamina, and the stalk corresponding to the petiole, its claw (unguis). The stalked petal is said to be unguiculate.
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