The following varieties of lettuce range from the heading types popular in Japan to stem lettuce and "A Choy," which originated in China. The head lettuces are delightful in salads—crisp with delicate flavors that need very little dressing. Stem lettuce looks something like a combination between celery and lettuce. The stems are cut into small "matchstick" pieces for salads or into larger pieces for stir-fries and soups. The younger leaves are good in salads, as well. More mature leaves tend to become bitter. Taiwan lettuce is referred to as "A Choy" and is a very popular green in Taiwan. Leaves are harvested at an early stage when tender and crispy.