Each of these systems may again be divided into two subsystems, according to the management of the annual growth or canes. In one, spurs of one, two, or three eyes are left for fruit production. This system is called short or spur pruning. In the other, long canes are left for fruit production. This is called long or cane pruning. In rare cases an intermediate form is adopted in which long spurs or short canes of five or six eyes are left. In cane pruning, each fruit cane is accompanied by one or two short renewal spurs. These must also accompany half-long pruning. Systems of pruning, when only long canes are left without renewal-spurs, are not in use in California. In all systems, replacing-spurs are left wherever and whenever needed. Other modifications are introduced by the manner of disposal of the fruit canes. These may be tied up vertically to a stake driven at the foot of each vine or bowed in a circle and tied to this same stake, or they may be tied laterally to wires stretching along the rows in a horizontal, ascending or descending direction. The different systems differ therefore in: (1) the shape, length, and direction of the trunk; (2) the arrangement of the arms; (3) the use of fruit spurs or fruit canes with renewal spurs; (4) the disposal of the fruit canes. The principal possibilities of the pruning are shown in the following table: A. HEAD PRUNING: VASE-FORM } { (_a_) Fruit spurs or } { 1. High trunk: } { (_b_) Half-long canes and renewal } { spurs or 2. Medium trunk: } with { } { (_c_) Fruit canes and renewal 3. Low trunk: } { spurs; canes vertical } { or bowed. B. HEAD PRUNING: FAN-SHAPED; TRELLISED 1. High trunk: Fruit canes and renewal spurs; canes descending. 2. Medium trunk: Fruit canes and renewal spurs; canes horizontal or ascending. C. CORDON PRUNING 1. Vertical: Spur; half-long; cane. 2. Horizontal-unilateral: Spur; half-long; cane. 3. Horizontal-bilateral: Spur; half-long; cane. All possible combinations indicated by this table represent 24 variations. Some of these combinations, however, are not used and some are rare. The most common are shown in Figs. 23, 24, 25, 26 and 27. Figure 23 B represents a headed, vase-formed vine, with a medium trunk and short fruit spurs. This is the most common system used in all parts of California and is suited for all small growing vines which bear on the lower buds, for most wine grapes and for Muscats. The unit of pruning in this case is a fruit spur of 1, 2, or 3 internodes, according to the vigor of the variety and of the individual cane. Figure 23 A differs from 23 B only in the higher trunk and longer arms. It is commonly used for Tokay and other large growing varieties, especially when growing in rich soil and when planted far apart.