_Figure 1._--The shaded part shows the extensive area where some form of the common poison-ivy is likely to be found. Other forms also may occur in parts of the same region. _Figure 2._--Large poison-ivy vine growing on a tree for support. This is the usual form of the common poison-ivy in wooded areas. _Figure 3._--_A_, Common poison-ivy growing in a hedge and on a shade tree on the edge of a lawn. _B_, Typical vine, showing leaves and the roots that attach it to the tree. The vining type most often occurs in wooded areas (fig. 2), where it depends upon trees for support. Vines often grow for many years, becoming several inches in diameter and quite woody. Slender vines may run along the ground, mixed with shrubbery, or take support from a large or small tree. That a plant growing along the edge of a lawn and into the shrubbery may be quite inconspicuous as compared with a vine climbing on a lawn tree is shown in figure 3. The vine readily develops roots when in contact with the ground or with any object that will support it. When the vines grow on trees these aerial roots attach the vine securely ( fig. 3. B). A rank growth of these roots often causes the vines on trees to have the general appearance of a "fuzzy" rope, which sometimes serves a good purpose for identification. The vines and roots apparently do not cause injury to the tree except where growth may be sufficient to cover the supporting plant and exclude sunlight or break the plant from excessive weight. The vining nature of the plant makes it well adapted to climbing over stone walls or on brick and stone houses. The fact that poison-ivy often becomes mixed in with ornamental shrubbery and vines often results in its cultivation as an ornamental vine by people who do not recognize the plant. An ivy plant growing on a house, as is shown in figure 4, is often prized by an unsuspecting owner. The vine is attractive and quite effective as an ornamental, but such use should not be tolerated, as it most certainly will result in cases of accidental poisoning and serve as propagating stock for more poison-ivy in the vicinity. _Figure 4._--Common poison-ivy growing on side of house with ornamental shrubs. This accidental or intentional use of the attractive vine may lead to many cases of accidental poisoning. _Figure 5._--Common poison-ivy growing along fence row. In open sunlight and over some large areas it is more of a shrub than a vine. _Figure 4._--Common poison-ivy growing on side of house with ornamental shrubs. This accidental or intentional use of the attractive vine may lead to many cases of accidental poisoning.