Right now the greenhouse is filled with bolted, flowering brassicas. Most brassicas have yellow flowers. Arugula flowers are totally different in color - they are cream colored with red viens. They do have the same number of flower petals and stamens.
Brassica florets are tasty when small, but once the stems elongate and the flowers open they are tough. Last year I have enough tat soi flowers to eat in a stir fry. This year I let everything bolt. Brassicas tend to bolt quickly in this greenhouse because there are so many plants in such a small area.
Varieties, clockwise from top left: wasabina, arugula, mizuna, tat soi, chinese pac choi, tokyo bekana.