A novel distillation tray useful as a horizontally disposed internal for a distillation column, especially a cryogenic distillation column, has a set of parallel horizontal pipes spaced from one another to support a pool of down-flowing liquid and to provide passage of up-flowing vapor through the spaces. At each end the pipes are connected to and communicate with a manifold. A number of these trays in a vertically tiered array are connected to one another as an assembly in the column. The assembly of the trays is provided by the manifolds at the two ends of the sets of pipes. In one construction the manifold for one set of pipes has an upward vertical extension that is also one manifold of the adjacent upper tray, while the other manifold for the first set of pipes has a downward vertical extension that is also one manifold of the adjacent lower tray. In another construction the manifold at one end of a set of pipes is connected to a pipe extending upwardly to the manifold of the adjacent upper tray, while the manifold at the other end is connected to the pipe that extends upwardly from the manifold at that end of the adjacent lower tray. The manifold of the lowermost tray that is not in communication with the manifold of the tray immediately above it is connected to a pipe extending through the wall of the column. The manifold of the uppermost tray of such assembly that is not in communication with a manifold of the tray below it is connected to a pipe extending through the column wall. Alternatively, that uppermost manifold has an opening to the chamber of the column so that fluid after passage through the assembly of trays is then introduced directly into the column as a feed for the column. As a second alternative, the set of pipes of the top tray of the assembly in the stripping section of a column can be short to feed the fluid to the chamber of the column. Columns containing the assembly of the trays in the stripping section and/or rectifying section are especially useful in novel distillation systems.