The corolla is tubular with a spreading limb, and varies widely in colour, being white, yellow, orange, crimson, scarlet, blue or purple.
From light 1, Corolla cut open with stamens.
The flowers are generally regular; the form of the corolla varies widely.
Thus in borage it is rotate, tubular in comfrey, funnel-shaped in hounds-tongue, and salvershaped in alkanet (Anchusa); the throat is often closed by scale-like outgrowths from the corolla, forming the so-called corona.
A departure from the usual regular corolla occurs in Echium and a few allied genera, where it is oblique; in Lycopsis it is also bent.
The scales around the throat of the corolla protect the pollen and honey from wet or undesirable visitors, and by their difference in colour from the corolla-lobes, as in the yellow eye of forget-me-not, may serve to indicate the position of the honey.
Corolla split open.
- (I) Flower of Borage; (2) same in vertical section enlarged; (3) horizontal plan of flower; (4) flower of Comfrey after removal of corolla, showing unripe fruit; (I) and (4) natural size.
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.
Opulus, guelder rose, in the cultivated forms of which the corolla has become enlarged at the expense of the essential organs and the flowers are neuter.
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 corolla is generally funnelshaped, more rarely bell-shaped or tubular; the outer face is often marked out in longitudinal areas, five well-defined areas tapering from base to apex, and marked with longitudinal striae corresponding to the middle of the petals, and alternating with five non-striated weaker triangular areas; in the bud the latter are folded inwards, the stronger areas being exposed and showing a twist to the right.
The flowers are large, yellow, scented and a little drooping, with a corolla deeply cleft into six lobes and a bell-shaped corona which is crisped at the margin; they appear in March or April.
Terminal scorpioid cymes, small blue, pink or white flowers, a five-cleft persistent calyx, a salveror funnel-shaped corolla, having its mouth closed by five short scales and hard, smooth, shining nutlets.
Palustris, is a perennial plant growing to a height of 6 to 18 in., with rootstock creeping, stem clothed with lax spreading hairs, leaves light green, and somewhat shining, buds pink, becoming blue as they expand, and corolla rotate, broad, with retuse lobes and bright blue with a yellow centre.
The divisions of the calyx extend only about one-third the length of the corolla, whereas in the other British species of Myosotis it is deeply cleft.
He described about 8000 species of plants, and distributed them into twenty-two classes, chiefly according to the form of the corolla, distinguishing herbs and under-shrubs on the one hand from trees and shrubs on the other.
In very many cases the pollen is carried to the stigma by elongation, curvature or some other movement of the filament, the style or stigma, or corolla or some other part of the flower, or by correlated movements of two or more parts.
Many plants produce, in addition to ordinary open flowers, so-called cleistogamous flowers, which remain permanently closed but which notwithstanding produce fruit; in these the corolla is inconspicuous or absent and the pollen grows from the anther on to the stigma of the same flower.
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.
The flowers are borne singly in the leaf-axils on a stalk about half the length of the leaf and jointed and bent in the middle; the corolla is blue-purple.
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."
The corolla has from five to nine petals, cohering at the base.
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.
In the second case the outer series (calyx of sepals) is generally green and leaf-like, its function being to protect the rest of the flower, especially in the bud; while the inner series (corolla of petals) is generally white or brightly coloured, and more delicate in structure, its function being to attract the particular insect or bird by agency of which pollination is effected.
Apart from this, botanists are generally agreed that the concrescence of parts of the flower-whorls - in the gynaeceum as the seed-covering, and in the corolla as the seat of attraction, more than in the androecium and the calyx - is an indication of advance, as is also the concrescence that gives the condition of epigyny.
In his arrangement the last subdivision disappears, and the Dicotyledons fall into two groups, a larger containing those in which both calyx and corolla are present in the flower, and a smaller, Monochlamydeae, representing the Apetalae and Diclines Irregulares of Jussieu.
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 sepals are leafy and persistent; the corolla is generally divided into a longer or shorter tube and a limb which is spreading, as in primrose, or reflexed, as in Cyclamen; in Soldanella it is bell-shaped; in Lysimachia the tube is often very short, the petals appearing almost free; in Glaux the petals are absent.
The five stamens spring from the corolla-tube and are FIG.
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 flowers are large, yellow, scented and a little drooping, with a corolla deeply cleft into six lobes, and a central bell-shaped nectary, which is crisped at the margin.
The branches and corolla are purple, the fruit woolly.