Choy Sum (also spelled choi sum) is a leafy vegetable commonly used in Chinese cuisine. It is a member of the Brassica genus and the Brassicaceae (mustard) family (Brassica rapa var. parachinensis or Brassica chinensis var. parachinensis). Choy sum is a transliteration of the Cantonese name (Chinese: 菜心), which can be literally translated as "vegetable heart". It is also known as Chinese Flowering Cabbage.