No, not at all
From wiki
"
Cauliflower is one of several vegetables in the species
Brassica oleracea in the genus
Brassica, which is in the
Brassicaceae (or Mustard) family. .....
Brassica oleracea also includes
broccoli,
Brussels sprouts,
cabbage,
collard greens, and
kale, collectively called
"cole" crops,
[2] though they are of different
cultivar groups."
From Britannica.com
"
Cauliflower, (
Brassica oleracea, variety botrytis), highly modified form of
cabbage in the mustard family (
Brassicaceae), grown for its edible masses of partially developed
flower structures and fleshy stalks. "