Soft-wooded deciduous shrubs, climbing high into trees. Stems terete, green, swollen at the nodes; pith large, rounded, continuous, pale. Buds small, sessile, rounded, superposed on a silky area, with 1 silky scale; terminal bud absent. Leaf-scars alternate, U-shaped; bundle-traces 3; stipule-scars lacking.
Fig. 93. Aristolochia durior.
1. A. durior Hill. Dutchman's Pipe. Pipe vine. (A. macro-phylla Lam.). A twining vine sometimes more than 10 m. high and 3 dm. in diameter, the branches slender, terete, green, glabrous; pith large. Rich woods, mountains of Pennsylvania and West Virginia to Georgia and Alabama (Fig. 93).