Formerly the sloe, P. spinosa, was thought to be the parent of all our plums; but now this honour is very commonly accorded to P. insititia or the bullace, which is found wild in the Caucasus and N.-Western India, and is naturalised in England. (10/71. See an excellent discussion on this subject in Hewett C. Watson 'Cybele Britannica' volume 4 page 80.) It is not at all improbable, in accordance with some observations made by Mr. Rivers (10/72. 'Gardener's Chronicle' 1865 page 27.), that both these forms, which some botanists rank as a single species, may be the parents of our domesticated plums. Another supposed parent-form, the P. domestica, is said to be found wild in the region of the Caucasus. Godron remarks (10/73. 'De l'Espece' tome 2 page 94. On the parentage of our plums see also Alph. De Candolle 'Geograph. Bot.' page 878. Also Targioni-Tozzetti 'Journal Hort. Soc.' volume 9 page 164. Also Babington 'Manual of Brit. Botany' 1851 page 87.) that the cultivated varieties may be divided into two main groups, which he supposes to be descended from two aboriginal stocks; namely, those with oblong fruit and stones pointed at both ends, having narrow separate petals and upright branches; and those with rounded fruit, with stones blunt at both ends, with rounded petals and spreading branches. From what we know of the variability of the flowers in the peach and of the diversified manner of growth in our various fruit-trees, it is difficult to lay much weight on these latter characters. With respect to the shape of the fruit, we have conclusive evidence that it is extremely variable: Downing (10/74. 'Fruits of America' pages 276, 278, 284, 310, 314. Mr. Rivers raised ('Gardener's Chronicle' 1863 page 27) from the Prune-peche, which bears large, round, red plums on stout, robust shoots, a seedling which bears oval, smaller fruit on shoots that are so slender as to be almost pendulous.) gives outlines of the plums of two seedlings, namely, the red and imperial gages, raised from the greengage; and the fruit of both is more elongated than that of the greengage. The latter has a very blunt broad stone, whereas the stone of the imperial gage is "oval and pointed at both ends." These trees also differ in their manner of growth: "the greengage is a very short- jointed, slow-growing tree, of spreading and rather dwarfish habit;" whilst its offspring, the imperial gage, "grows freely and rises rapidly, and has long dark shoots." The famous Washington plum bears a globular fruit, but its offspring, the emerald drop, is nearly as much elongated as the most elongated plum figured by Downing, namely, Manning's prune. I have made a small collection of the stones of twenty-five kinds, and they graduate in shape from the bluntest into the sharpest kinds. As characters derived from seeds are generally of high systematic importance, I have thought it worth while to give drawings of the most distinct kinds in my small collection; and they may be seen to differ in a surprising manner in size, outline, thickness, prominence of the ridges, and state of surface. It deserves notice that the shape of the stone is not always strictly correlated with that of the fruit: thus the Washington plum is spherical and depressed at the pole, with a somewhat elongated stone, whilst the fruit of the Goliath is more elongated, but the stone less so, than in the Washington. Again, Denyer's Victoria and Goliath bear fruit closely resembling each other, but their stones are widely different. On the other hand, the Harvest and Black Margate plums are very dissimilar, yet include closely similar stones.
The varieties of the plum are numerous, and differ greatly in size, shape, quality, and colour,—being bright yellow, green, almost white, blue, purple, or red. There are some curious varieties, such as the double or Siamese, and the Stoneless plum: in the latter the kernel lies in a roomy cavity surrounded only by the pulp. The climate of North America appears to be singularly favourable for the production of new and good varieties; Downing describes no less than forty, of which seven of first-rate quality have been recently introduced into England. (10/75. 'Gardener's Chronicle' 1855 page 726.) Varieties occasionally arise having an innate adaptation for certain soils, almost as strongly pronounced as with natural species growing on the most distinct geological formations; thus in America the imperial gage, differently from almost all other kinds, "is peculiarly fitted for DRY LIGHT soils where many sorts drop their fruit," whereas on rich heavy soils the fruit is often insipid. (10/76. Downing 'Fruit Trees' page 278.) My father could never succeed in making the Wine-Sour yield even a moderate crop in a sandy orchard near Shrewsbury, whilst in some parts of the same county and in its native Yorkshire it bears abundantly: one of my relations also repeatedly tried in vain to grow this variety in a sandy district in Staffordshire.
Mr. Rivers has given (10/77. 'Gardener's Chronicle' 1863 page 27. Sageret in his 'Pomologie Phys.' page 346 enumerates five kinds which can be propagated in France by seed: see also Downing 'Fruit Trees of America' page 305, 312, etc.) a number of interesting facts, showing how truly many varieties can be propagated by seed. He sowed the stones of twenty bushels of the greengage for the sake of raising stocks, and closely observed the seedlings; all had the smooth shoots, the prominent buds, and the glossy leaves of the greengage, but the greater number had smaller leaves and thorns." There are two kinds of damson, one the Shropshire with downy shoots, and the other the Kentish with smooth shoots, and these differ but slightly in any other respect: Mr. Rivers sowed some bushels of the Kentish damson, and all the seedlings had smooth shoots, but in some the fruit was oval, in others round or roundish, and in a few the fruit was small, and, except in being sweet, closely resembled that of the wild sloe. Mr. Rivers gives several other striking instances of inheritance: thus, he raised eighty thousand seedlings from the common German Quetsche plum, and "not one could be found varying in the least, in foliage or habit." Similar facts were observed with the Petite Mirabelle plum, yet this latter kind (as well as the Quetsche) is known to have yielded some well-established varieties; but, as Mr. Rivers remarks, they all belong to the same group with the Mirabelle.
CHERRIES (Prunus cerasus, avium, etc.).
Botanists believe that our cultivated cherries are descended from one, two, four, or even more wild stocks. (10/78. Compare Alph. De Candolle 'Geograph. Bot.' page 877. Bentham and Targioni-Tozzetti in 'Hort. Journal' volume 9 page 163; Godron 'De l'Espece' tome 2 page 92.) That there must be at least two parent species we may infer from the sterility of twenty hybrids raised by Mr. Knight from the morello fertilised by pollen of the Elton cherry; for these hybrids produced in all only five cherries, and one alone of these contained a seed. (10/79. 'Transact. Hort. Soc.' volume 5 1824 page 295.) Mr. Thompson (10/80. Ibid second series volume 1 1835 page 248.) has classified the varieties in an apparently natural method in two main groups by characters taken from the flowers, fruit, and leaves; but some varieties which stand widely separate in this classification are quite fertile when crossed; thus Knight's Early Black cherries are the product of a cross between two such kinds.
Mr. Knight states that seedling cherries are more variable than those of any other fruit-tree. (10/81. ) In the Catalogue of the Horticultural Society for 1842 eighty varieties are enumerated. Some varieties present singular characters: thus, the flower of the Cluster cherry includes as many as twelve pistils, of which the majority abort; and they are said generally to produce from two to five or six cherries aggregated together and borne on a single peduncle. In the Ratafia cherry several flower- peduncles arise from a common peduncle, upwards of an inch in length. The fruit of Gascoigne's Heart has its apex produced into a globule or drop; that of the white Hungarian Gean has almost transparent flesh. The Flemish cherry is "a very odd-looking fruit," much flattened at the summit and base, with the latter deeply furrowed, and borne on a stout, very short footstalk. In the Kentish cherry the stone adheres so firmly to the footstalk, that it could be drawn out of the flesh; and this renders the fruit well fitted for drying. The Tobacco-leaved cherry, according to Sageret and Thompson, produces gigantic leaves, more than a foot and sometimes even eighteen inches in length, and half a foot in breadth. The weeping cherry, on the other hand, is valuable only as an ornament, and, according to Downing, is "a charming little tree, with slender, weeping branches, clothed with small, almost myrtle-like foliage." There is also a peach-leaved variety.
Sageret describes a remarkable variety, LE GRIOTTIER DE LA TOUSSAINT, which bears at the same time, even as late as September, flowers and fruit of all degrees of maturity. The fruit, which is of inferior quality, is borne on long, very thin footstalks. But the extraordinary statement is made that all the leaf-bearing shoots spring from old flower-buds. Lastly, there is an important physiological distinction between those kinds of cherries which bear fruit on young or on old wood; but Sageret positively asserts that a Bigarreau in his garden bore fruit on wood of both ages. (10/82. These several statements are taken from the four following works, which may, I believe, be trusted: Thompson in 'Hort. Transact.' see above; Sageret 'Pomologie Phys.' 1830 pages 358, 364, 367, 379; 'Catalogue of the Fruit in the Garden of Hort. Soc.' 1842 pages 57, 60; Downing 'The Fruits of America' 1845 pages 189, 195, 200.)
APPLE (Pyrus malus).
The one source of doubt felt by botanists with respect to the parentage of the apple is whether, besides P. malus, two or three other closely allied wild forms, namely, P. acerba and praecox or paradisiaca, do not deserve to be ranked as distinct species. The P. praecox is supposed by some authors (10/83. Mr. Lowe states in his 'Flora of Madeira' quoted in 'Gardener's Chronicle' 1862 page 215 that the P. malus, with its nearly sessile fruit, ranges farther south than the long-stalked P. acerba, which is entirely absent in Madeira, the Canaries, and apparently in Portugal. This fact supports the belief that these two forms deserve to be called species. But the characters separating them are of slight importance, and of a kind known to vary in other cultivated fruit-trees.) to be the parent of the dwarf paradise stock, which, owing to the fibrous roots not penetrating deeply into the ground, is so largely used for grafting; but the paradise stocks, it is asserted (10/84. See 'Journ. of Hort. Tour, by Deputation of the Caledonian Hort. Soc.' 1823 page 459.) cannot be propagated true by seed. The common wild crab varies considerably in England; but many of the varieties are believed to be escaped seedlings. (10/85. H.C. Watson 'Cybele Britannica' volume 1 page 334.) Every one knows the great difference in the manner of growth, in the foliage, flowers, and especially in the fruit, between the almost innumerable varieties of the apple. The pips or seeds (as I know by comparison) likewise differ considerably in shape, size, and colour. The fruit is adapted for eating or for cooking in various ways, and keeps for only a few weeks or for nearly two years. Some few kinds have the fruit covered with a powdery secretion, called bloom, like that on plums; and "it is extremely remarkable that this occurs almost exclusively among varieties cultivated in Russia." (10/86. Loudon's 'Gardener's Mag.' volume 6 1830 page 83.) Another Russian apple, the white Astracan, possesses the singular property of becoming transparent, when ripe, like some sorts of crabs. The API ETOILE has five prominent ridges, hence its name; the API NOIR is nearly black: the TWIN CLUSTER PIPPIN often bears fruit joined in pairs. (10/87. See 'Catalogue of Fruit in Garden of Hort. Soc.' 1842 and Downing 'American Fruit Trees.') The trees of the several sorts differ greatly in their periods of leafing and flowering; in my orchard the COURT PENDU PLAT produces leaves so late, that during several springs I thought that it was dead. The Tiffin apple scarcely bears a leaf when in full bloom; the Cornish crab, on the other hand, bears so many leaves at this period that the flowers can hardly be seen. (10/88. Loudon's Gardener's Magazine' volume 4 1828 page 112.) In some kinds the fruit ripens in mid- summer; in others, late in the autumn. These several differences in leafing, flowering, and fruiting, are not at all necessarily correlated; for, as Andrew Knight has remarked (10/89. 'The Culture of the Apple' page 43. Van Mons makes the same remark on the pear 'Arbres Fruitiers' tome 2 1836 page 414.), no one can judge from the early flowering of a new seedling, or from the early shedding or change of colour of the leaves, whether it will mature its fruit early in the season.
The varieties differ greatly in constitution. It is notorious that our summers are not hot enough for the Newtown Pippin (10/90. Lindley's 'Horticulture' page 116. See also Knight on the Apple-Tree, in 'Transact. of Hort. Soc.' volume 6 page 229.), which is the glory of the orchards near New York; and so it is with several varieties which we have imported from the Continent. On the other hand, our Court of Wick succeeds well under the severe climate of Canada. The Caville rouge de Micoud occasionally bears two crops during the same year. The Burr Knot is covered with small excrescences, which emit roots so readily that a branch with blossom-buds may be stuck in the ground, and will root and bear a few fruit even during the first year. (10/91. Transact. Hort. Soc.' volume 1 1812 page 120.) Mr. Rivers has recently described (10/92. 'Journal of Horticulture' March 13, 1866 page 194.) some seedlings valuable from their roots running near the surface. One of these seedlings was remarkable from its extremely dwarfed size, "forming itself into a bush only a few inches in height." Many varieties are particularly liable to canker in certain soils. But perhaps the strangest constitutional peculiarity is that the Winter Majetin is not attacked by the mealy bug or coccus; Lindley (10/93. 'Transact. Hort. Soc.' volume 4 page 68. For Knight's case see volume 6 page 547. When the coccus first appeared in this country it is said (volume 2 page 163) that it was more injurious to crab-stocks than to the apples grafted on them. The Majetin apple has been found equally free of the coccus at Melbourne in Australia ('Gardener's Chronicle' 1871 page 1065). The wood of this tree has been there analysed, and it is said (but the fact seems a strange one) that its ash contained over 50 per cent of lime, while that of the crab exhibited not quite 23 per cent. In Tasmania Mr. Wade ('Transact. New Zealand Institute' volume 4 1871 page 431) raised seedlings of the Siberian Bitter Sweet for stocks, and he found barely one per cent of them attacked by the coccus. Riley shows ('Fifth Report on Insects of Missouri' 1873 page 87) that in the United States some varieties of apples are highly attractive to the coccus and others very little so. Turning to a very different pest, namely, the caterpillar of a moth (Carpocapsa pomonella), Walsh affirms ('The American Entomologist' April 1869 page 160) that the maiden-blush "is entirely exempt from apple-worms." So, it is said, are some few other varieties; whereas others are "peculiarly subject to the attacks of this little pest.") states that in an orchard in Norfolk infested with these insects the Majetin was quite free, though the stock on which it was grafted was affected: Knight makes a similar statement with respect to a cider apple, and adds that he only once saw these insects just above the stock, but that three days afterwards they entirely disappeared; this apple, however, was raised from a cross between the Golden Harvey and the Siberian Crab; and the latter, I believe, is considered by some authors as specifically distinct.