The Nectarine (P. lævis) only differs from the peach in the epicarp, or outer covering of the pulpy part, being smooth instead of downy. Of both fruits there are two kinds, one called free-stone, from their parting freely with the stone; and the other cling-stone, from the stone clinging to the fibres of the pulp.
The Apricot (Armeniaca vulgaris) agrees with the preceding genus in its flowers; but it differs in its fruit, its stone being sharp at one end and blunt at the other, with a furrow on each side, but the rest of the surface smooth. Thus my readers will perceive that the Peach and the Apricot, though so different from each other as to be recognised at a glance, are yet botanically so very closely allied, as to be distinguished only by the stone. The leaves indeed differ in form, but in other respects they are exactly the same.
Fig. 25.—Flowers and fruit of the Sloe.
The Sloe (Prunus spinosa) is supposed by some botanists to be the origin of our cultivated plum, though others make it a separate species under the name of Prunus domestica. The flowers in both are solitary (see fig. 25), and consist of a five-toothed calyx (a) which is united at the base, and in the lining of which the stamens are inserted as shown at (b). The ovary has a thick style and capitate stigma (c), and the fruit is a drupe (d). In these particulars therefore the plum agrees with the preceding genera; but it will be found to differ in the skin of the pericarp, which is quite smooth and covered with a fine bloom; this, indeed, and its stone being pointed at both ends constitute the chief botanical distinctions between the fruit of the plum and that of the apricot, as in other respects they are alike. Both the plum and the apricot have footstalks, and in this differ from the peach and the nectarine, which are without. The leaves of the plum differ from those of the other genera in being convolute, that is, rolled up, in the bud.
The Cherry (Cerasus vulgaris) differs from the plum in the skin of the pericarp being destitute of bloom, and in several flowers springing from each bud, in what botanists call a fascicled
Fig. 26.—Flowers and stone of the Cherry. umbel (see a) in fig. 26. The pedicels (b) are also much longer; the petals (c) are indented in the margin; the style (d) is more slender; and the stone (e) is smooth and much more globose. The number of the stamens, and the manner in which they are inserted in the lining of the calyx, is the same in both genera (see f); but the leaves are different, for those of the Cherry are folded down the middle, when young, like those of the peach and almond; while those of the plum are rolled up.