CHAPTER III.
THE ORDER ROSACEÆ, ILLUSTRATED BY DIFFERENT KINDS OF ROSES; THE POTENTILLA; THE STRAWBERRY; THE RASPBERRY; SPIRÆA; KERRIA OR CORCHORUS JAPONICA; THE ALMOND; THE PEACH AND NECTARINE; THE APRICOT; THE PLUM; THE CHERRY; THE APPLE; THE PEAR; THE MOUNTAIN ASH; THE WHITE BEAM TREE; QUINCE; PYRUS OR CYDONIA JAPONICA; THE HAWTHORN; THE INDIAN HAWTHORN; THE MEDLAR; PHOTINIA; ERIOBOTRYA; COTONEASTER; AMELANCHIER; BURNET; AND ALCHEMILLA OR LADIES’-MANTLE.
All the numerous plants which compose this large order agree more or less with the rose in the construction of their flowers, though they differ widely in the appearance of their fruit. They all agree in having the receptacle dilated, so as to form a lining to the lower part of the calyx, and in the upper part of this lining the stamens and petals are inserted above the ovary; and the anthers are innate, that is, the filament is inserted only in the lower part. The leaves also have generally large and conspicuous stipules; and they are frequently compound, that is, composed of several pairs of leaflets, placed exactly opposite to each other; though the leaves themselves are never opposite to each other, but are placed alternately on the main stem. These characters are common to the order; but the plants included in it differ from each other so much in other respects, that it has been found necessary to redivide Rosaceæ into tribes, of which the following six contain plants common in British gardens.
TRIBE I.—ROSEÆ.
Fig. 20.—Rosa Fosteri.
The flowers of the wild Rose have the lower part of the calyx tubular and fleshy (from being lined with the dilated receptacle) and the upper part divided into five leafy sepals, which enfold the bud, and remain on after the expansion of the corolla. In Rosa Fosteri, (see fig. 20,) and its near ally the Dog rose (R. canina), the sepals (a) do not extend far beyond the petals of the bud; but in some species, as in Rosa cinnamonea and its allies, the sepals are so large and long, that they assume the character of little leaves,
Fig. 21.—Ovary of the Ayrshire rose with a detached seed. The corolla is cup-shaped, and it is composed of five equal petals, each of which is more or less indented in the margin, as shown at b. In the centre of the flower the receptacle forms a kind of disk which completely fills the opening or throat of the calyx; in most species covering the carpels and their styles and only leaving the stigmas free, though in the Ayrshire rose (R. arvensis), and its allies, the styles are united, so as to form a column, which projects considerably above the disk (see fig. 21). The pitcher-shaped part of the calyx when the corolla falls becomes the hip (fig. 20 c), and serves as a covering or false pericarp to the numerous bony carpels or nuts which contain the seed. These nuts are each enveloped in a hairy cover (see fig. 20 d, and fig. 21 a,) and each contains only one seed which it does not open naturally to discharge: hence, the seeds of roses when sown are a long time before they come up. Fig. 22 is the ripe fruit of Rosa cinnamonea, cut in two to