In article , Miss
Perspicacia Tick writes

Honesty - also known as Shepherd's Purse. What you're referring to as
"flowers" aren't flowers at all, but the seed pods. The flowers have 5 (I
think) petals and are deep purple.

4. It's a member of the cabbage family Crucifereae - so named because
a characteristic of the family is the four petals arranged in cross
shape.
--
Kay
"Do not insult the crocodile until you have crossed the river"