What are the daisy-like flowers florists use in arrangements? Unlike regular daisies, these have green centers.
The Wisconsin Master Gardeners published a good article on the web called Green Flowers. If you scroll down the page, you'll see several flowers with green centers. According to the article "Purple coneflower cultivars (Echinacea purpurea) – 'White Swan' has white flowers with green cones in the middle (until they mature and turn dark brown). ‘Green Envy’ has large 4" flowers that emerge a lime green, then the petals develop a rose-pink flush tipped with lime green (more pink than green, not like the promotional photos). 'Green Jewel' has greenish, quilled petals. (see photo below); 'Coconut Lime' has short, white double petals surrounding a large, almost fuzzy-looking green center."
For more information on green flowers, look at Alison Hoblyn's Green flowers : unexpected beauty for the garden, container or vase, available to PHS members for borrowing.