The peaches of New York

by U. P. Hedrick

PLACE OF THE PEACH IN THE GENUS PRUNUS

The genus Prunus is without peer in the number of distinct, natural, esculent products it furnishes man. Here belong the stone-fruits—peaches, plums, cherries, almonds and apricots, represented by some forty edible species, which, through long domestication, have been broken up into not less than 5000 orchard-varieties, of which at least 3000 are now under cultivation. Of the two-score cultivated species of this genus, Prunus persica, the common peach, is easily the most remarkable when judged either by the senses which make foods palatable and pleasant or by the criteria that establish the commercial worth of a product. As virtues which give the peach leading place among stone-fruits, we may specify: Wider distribution and consequently commoner cultivation and a greater number of varieties; larger size, greater beauty, pleasanter and more diversified taste, and more culinary uses than other stone-fruits; and greater productiveness, more rapid growth and earlier fruiting of the trees than most of the species of the genus. The place of the peach in the genus Prunus is thus easily established from a horticultural point of view, but it is a much more difficult matter to make clear its botanical standing among the species with which it is considered botanically related.

The botanical relations of the several stone-fruits to each other have been set forth in the foregoing books of this series on plums and cherries, but, for the convenience of those who may not have these treatises, a summary of the relationships of the species of Prunus is presented. Besides, greater emphasis on several differences between the peach and its congeners is needed. In particular, since some notable naturalists have held that the peach is a modified almond, the differences between these two fruits must be more clearly set forth.

Nearly every botanist who has done much towards classifying plants has grouped the stone-fruits according to a plan of his own and there are, therefore, many classification schemes and consequently a most confused nomenclature for this genus. Happily, the pitfalls in synonomy dug by botanists need not worry horticulturists; for each of the stone-fruits constitutes a distinct horticultural group. In tree or fruit of peach, plum, cherry, apricot, or almond, who could mistake one for another? For horticultural purposes we accept as best one of the oldest and yet one of the most commonly used classifications which places in one genus all of the stone-fruits. What are the lines of cleavage between the several stone-fruits of common cultivation?

Stone-fruits fall naturally into two distinct groups. In the first the leaves are rolled in the buds—convolute. The plums and the apricots belong to this section. In the buds of the other group the leaves are folded lengthwise along the midrib—conduplicate. To this section belong almonds, peaches and cherries. The two sections seem to be united in this matter of disposition of leaves in the bud, it should be said in passing, by a few species of American plums which are conduplicate in vernation. The second section is further subdivided by very marked differences in the fruits. The fruits of the peach and almond are larger than those of the cherry, less juicy,—in the case of the almond almost dry,—hirsute (except in the nectarine), and are borne without stems; and the blossoms usually appear long before the opening of the leaves. Cherry-fruits are always juicy, usually glabrous, and are borne on more or less distinct stems; and the blossoms appear with the leaves. Botanists who put these fruits in one genus usually redivide according to the characters given so that the plum and apricot stand in one sub-genus (Euprunus), the almond and peach in another (Amygdalus), and the cherry in a third (Cerasus).

Differentiating more closely, we find that it is not so easy to distinguish between the peach and the almond. The likenesses are so many and so apparent that it is not to be wondered that Knight, whose theory we have discussed on a foregoing page, came to the conclusion that the peach is a modified almond, or that Darwin, with his belief that plants came sooner or later to express their environmental conditions, should be inclined to believe that the peach is an evolution from the almond. It is easy to imagine that countless ages ago—how long since is but an invitation to argue—the two species merged into one. Offspring of the parent-species once established in distinct soil and climatic conditions—the peach in China, the almond in southwestern Asia—differentiation began and in time each region was represented by a species of its own. Such an occurrence is but one of the commonplaces of evolution; but Knight, Lindley and Darwin thought they saw evidence that the separation came after the almond, the supposed parent-species, had been domesticated, the steps being from fleshy almond to bad clingstone, to good clingstone, to freestone, to nectarine. The arguments against such a descent have been given elsewhere.

The chief differences between the two species are to be found in the matured fruits though, at first thought, it might appear that these are not greater than those found in widely separated varieties of either of the two species. The fruits of the peach and the almond are, however, much more widely separated than any of the varieties of either species, inasmuch as the differences are several and have to do with parts not usually affected by cultivation and not the subject of selection by the cultivator. Thus, the fruit of the peach is a delectable esculent; that of the almond inedible; the flesh of the peach, the mesocarp, is soft, fleshy, juicy; that of the almond thin, tough and leathery; the pit of the peach must be removed while that of the almond drops naturally from the hard flesh which splits at maturity. The differences between the pits of the two species are quite as marked as in the flesh of the fruit. The pit of the peach is deeply sculptured, pitted, and of a bone-like consistency; that of the almond is nearly smooth and in most varieties is much thinner and of softer texture. The differences in the kernels are such as could easily be brought about by selection, some peach-kernels being sweet and edible and some almond-kernels being too bitter to be palatable.

Coming to the tree-characters we find that there are several which differ sufficiently to give each of the two fruits distinct specific rank. The winter aspect of the two trees is wholly different. The almond resembles a young apple tree in color of bark more than it does the peach and has, too, a head much like that of a broad-topped, much-branched apple. In foliage the distant aspect is much the same, but examined closely there are several distinctions that hold in comparing the two species. The leaves of the peach are more broadly lanceolate than those of the almond, coarsely serrate or crenate while the margins of almond-leaves are finely serrate. The glands on the leaf-stalk or leaf of the peach are globose, reniform or mixed; on the almond, the glands are globose. The flowers in the two species are similar but the time of flowering is markedly different. The color of the petals in both varies from pale pink to deep pink with occasional pure white forms; the flowers of true almonds are always large while those of the peach are about equally divided between large and small. The almond, in New York, is out of bloom before flowers of the peach appear, the difference in blooming-time being from one to three weeks.