Lactuca sativa asparagina - Celtuce.
Cut at the right moment, celtuce is crisp and crunchy with a slightly bitter taste, similar to chicory or endive.
Stems should be cut for the table when they are 25-30cm high.
Remove the leaves (they can be used for lettuce soup or salads), split the stem from top to bottom and it is ready to eat.
Serve it as you would celery. Only easier to grow!