Plantius Maximus

I am marrying into a family of plant geniuses.  I am sure that has a name like plantius geniusium or something but I wouldn’t know it. Like the colors of my bridesmaids dresses my thumb is black (hint ladies, that’s a hint!) I saw this photo yesterday. What is that dark purple flower? Gorgeous eh? Help us Steude’s, you’re the only ones who can!