Michaelmas daisy 
noun
A North American aster with numerous pinkish-lilac daisy-like flowers which bloom around Michaelmas.
- Aster novi-belgii, family Compositae.
- Flowers of Michaelmas daisy (A. novi-belgii) come mostly in shades of blue; ‘Climax’ has true blue flowers.
- Flat topped flowerheads like achillea and open daisy-like flowers such as Michaelmas daisies are particularly attractive to insects and butterflies as they are very visible and accessible.