If you don't really get it, i'll break it down to you. For one, if you've never read the manga, there's a scene where Black Star is referring to himself as the night sky and states that if he's "the night sky, then the sparkling stars are Tsubaki."
Ayame is the Japanese name for Iris which is also known as Moon Flower (or at least I read that on some website)... so you can piece the rest together from there I'm sure '