In the sixteenth century Savoy cabbage in The Netherlands had white flowers, while at present this cabbage variety has yellow flowers. In the same century, the branching form ‘Ghehackelde kool’ may have had cream flowers or white flowers like the present day Portuguese tronchuda kale and the Chinese Brassica alboglabra.

, , ,
Acta botanica neerlandica

CC BY 3.0 NL ("Naamsvermelding")

Koninklijke Nederlandse Botanische Vereniging

A.C. Zeven. (1988). Flower colour of two forms of Brassica oleracea in the sixteenth century. Acta botanica neerlandica, 37(4), 531–532.