Besides these divisions of the species cultivated for their fruits botanists describe several botanical forms which either have no horticultural value or are cultivated exclusively as ornamentals. It is not necessary to discuss these in a pomological work. Of these botanical derivatives of Prunus cerasus, Schneider enumerates nine and three hybrids between this and other species.[8]

PRUNUS AVIUM Linnaeus.

PRUNUS AVIUM (YELLOW SPANISH)

PRUNUS AVIUM (DOUBLE FLOWERING)

Tree reaching a height of thirty to forty feet, vigorous, upright-spreading, open-topped, semi-hardy, usually with a central leader; trunk a foot or more in diameter roughened; branches rather stocky, smooth, dull ash-gray, with few small lenticels; branchlets thick, long, with long internodes, grayish-brown, smooth, with small, inconspicuous lenticels.

Leaves resinous at opening, more or less drooping, numerous, four to six inches long, two to three inches wide, strongly conduplicate, oblong-ovate, thin; upper surface dark green, rugose or sometimes smooth; lower surface dull green, more or less pubescent; apex acute, base more or less abrupt; margin coarsely and doubly serrate, glandular; petiole one and three-fourths inches long, slender, dull red, with from one to three small, globose, reddish glands on the stalk; stipules small, lanceolate, finely serrate, early caducous.

Buds rather small, of medium length, pointed, appressed or free, arranged singly or in small, scaly clusters at the tips of branchlets or on short spurs; leaf-scars prominent; blooming with or after the leaves; flowers white, one and one-quarter inches across; in clusters of two or three; pedicels one inch long, slender, glabrous; calyx-tube green or with a faint red tinge, brownish-yellow within, campanulate; calyx-lobes faintly tinged with red, long, acute, margin serrate, glabrous within and without, reflexed; petals oval, entire or crenate, tapering to a short, blunt claw; stamens nearly one-half inch long, thirty-five or thirty-six; anthers yellow; pistil glabrous, shorter than the stamens.

Fruit ripening in early July; about an inch in diameter, cordate; cavity deep, wide, abrupt; suture a line; apex roundish or pointed; color ranging from yellow through red to purplish-black; dots numerous, small, russet, inconspicuous; stem tinged with red, one and one-half inches long, adherent to the fruit; skin toughish, adherent to the pulp; flesh yellow, red, or dark purple with colorless or colored juice, tender to firm, sweet; stone semi-clinging, three-eighths of an inch long, not as wide as long, elliptical, flattened, blunt, with smooth surfaces.

Through its cultivated varieties Prunus avium is everywhere known in temperate climates as the Sweet Cherry. In the wild state it is variously called Mazzard, Bird, Wild, Crab and the Gean cherry. It is not as hardy a species as Prunus cerasus and is, therefore, less generally grown but still is a favorite orchard, dooryard and roadside plant in all mid-temperate regions. It refuses to grow, however, in the warmest and coldest parts of the temperate zones. Wherever the species thrives as an orchard plant it is to be found growing spontaneously along fences and roadsides and in open woods from seeds distributed by birds. The fruits of these wild Sweet Cherries are usually small and the flesh thin and dry, often unpalatable; but, on the other hand, trees are sometimes found as escapes from cultivation which rival in their products the orchard-grown cherries. It is from reverted seedlings that the description of the species herewith given has been made. The number of cultivated varieties of Prunus avium listed in The Cherries of New York is 549.

The habitat of the species and its history as a cultivated plant are given in the following chapter. A further point of horticultural interest as regards its habitat is that wherever found truly wild, as in its original home in southern and central Europe and Asia Minor, it is to be found in moderately dry, calcareous soils and seldom in the shade, preferring always warm, sunny sites, as gravelly or stony hillsides. These predilections cling to the species in its cultivated varieties. Prunus avium differs from Prunus cerasus in an important horticultural character as the two species grow spontaneously—the former suckers from the root little or not at all, making it a suitable plant for a stock in orchard work, while the latter suckers so much as to make it unfit for use as a stock.