Small cabbage -related plant ( Brassica oleracea , Gemmifera group).
A member of the mustard family , Brussels sprouts are widely grown in Europe and the U.S. In early stages of growth, the plant closely resembles the common cabbage, but the main stem grows to a height of 23 ft (6090 cm) and the axillary buds along the stem develop into small heads (sprouts) similar to heads of cabbage but measuring only 11.6 in. (2540 mm) in diameter. The plant requires a mild, cool climate and is harmed by hot weather. Highly nutritious, Brussels sprouts are a particularly good source of vitamins A and C.