The vascular system of lianas exhibits a number of shared features that result from convergent evolution and are independent of their taxonomic affinities. This chapter explores the vascular system of lianas in major lineages addressing different aspects of their anatomy, development, seasonal growth, and evolution. It summarizes the general aspects of the vascular system of lianas. The chapter provides new data that show how the vascular anatomy of lianas has evolved and diversified, and how lianas respond to environmental cues. The vascular system of lianas is special since scandent plants must cope with very specific physical constraints inherent to their habit, including water transport along extremely long stems, and the demand for flexibility to accommodate twining. A higher abundance of axial parenchyma has been recorded in many lianas species in comparison to closely related trees and shrubs.