Xylem: Vessels

Vessels are long tube-like elements of xylem formed by fusion of cells end to end; they are characteristic of angiosperms.
However, some primitive angiosperms such as Wintera, Trochodendron and Tetracentron lack vessels (vesselless angiosperms). So vessels are present in most, not all, angiosperms.
Among gymnosperms, vessels are found only in a few members of the order Gnetales (Gnetum, Ephedra, Welwitschia). Most gymnosperms have only tracheids.
So vessels are found in most of the angiosperms and a few gymnosperms.