The evolution of lianas has punctuated the history of land plants, with the angiosperm lineages representing the most recent stage of liana exploration. The model of lianas as fast-growing, disturbance-loving plants emerges largely from the function of eudicot and magnoliid angiosperms. This chapter looks at some specific properties of ecology and function, derived from functional aspects of stem hydraulics, which appear to be restricted to lianas. It charts the broad picture of xylem structure and function of angiosperm lianescence framed by what is known about the comparative ecophysiologies of eudicot/magnoliid and monocot lianas from temperate/ tropical zones. The chapter reviews the liana hydraulic paradigm illustrated by these angiosperm climbers. Finally, it explores how other climber lineages differ from generally accepted views about how lianas function hydraulically.