Linked from
The 5 pages that link to Brussels sprouts, each with the reason it gives.
Brassica oleraceaBroader topic: These stem buds are harvested as a distinctive vegetable crop.
BroccoliRelated: This crop emphasizes enlarged lateral buds rather than a terminal flower head.
CauliflowerCompared with: Its edible buds form along the stem rather than as one compact head.
Eruca sativaRelated: It is a familiar cultivated relative within the same plant family.