Brassica oleracea var. botrytis x italica.
Broccoflowers are a hybrid of Brassica oleracea var. botrytis (cauliflower) and
Brassica oleracea var. italica (common broccoli).
They are typical Brassica plants with a terminal head of green (from broccoli) aborted flowers (from the cauliflower).
They are in the Botrytis group.
J.F.