In closely related varieties it is sometimes essential to know the characteristics of growth in the orchard and the color of the young wood. The color and general appearance of an apple may be changed to a considerable extent by soil and climate, but the general habit of growth and color of young wood does not change materially. For reasons already set forth, however, the pomologist should strive to seek distinguishing characters in the fruit itself, and not be dependent upon the tree in orchard or nursery save as confirmatory evidence.
The growth of the healthy bearing tree may be strong and vigorous; vigorous and slender; stout and short-jointed; medium and vigorous. The form of top may be upright, upright spreading, spreading, round-headed, or upright.
Some European writers have made elaborate systems based on the form of the fruit. Downing gives only four classes as follows:
"In describing fruits, the word base means that part of the fruit in which the stem is planted; and apex, the blossom end, or crown, as it is sometimes termed. Forms are so much interwoven, as it were, one with another, that we have selected but four as the primary bases on which all others are built, and are subsidiary.
"These primary forms are roundish, oblate, conical, and oblong. The terms round, roundish, or globular, are sometimes used in connection, rather as qualifying expressions than as distinctive; for while the word roundish, which indicates the height and diameter as nearly equal, applies to many fruits, there is no perfectly round or globular apple known.
"Oblate indicates the height as much less than diameter. Conical, is when the fruit is roundish, having the apex end contracted. Oblong, is when the fruit is longer than broad, and having the apex and base of nearly the same breadth. Connected and subsidiary terms, such as roundish, conical, or conic, are when the apple unites the two primary forms of roundish and conical; or elongated conical, or conic, when the length is considerably beyond the breadth. Truncate conic, is when the fruit is flattened at the apex. Ribbed, or obscurely ribbed, when the surface has rising lines and channels from apex to base. Oblique, is when the fruit presents the appearance as of being one-sided, or when the axis is inclined to one side. Oblate, not symmetric, or sides unequal, when one side is less than the other. Corrugated, having depressed lines, furrows, or wrinkles. Acute, when narrowing to a sharp point. Obtuse, round or blunt. Abrupt, when the depression breaks off suddenly."
This is an imaginary straight line between the stem and the centre of the calyx. The axis is inclined when the fruit is oblique or lop-sided; short when oblate or the cavity and basin are deep; long when the fruit is oblong. The core-cells are axile when they meet the axis; abaxile when distant from it. When a section made through the apple at right angles to the axis is circular it is regular; if so true that it could be turned in a lathe, it is very regular; it may be irregular, compressed, or flattened sidewise, angular, furrowed, or ribbed, rarely triangular, quadrangular, or pentangular.