After the tip of a young plant stem is cut off, the stem stops growing in length but new branches arise from the nodes. Which meristem allows this regrowth?

Intercalary meristems are located at the base of internodes or just above the nodes. Removing the apical meristem stops vertical growth, but intercalary meristems remain active — letting the plant produce new branches from nodes. This is also why grasses re-grow after being cut by a lawn mower.