Sondi, Jema, and Zook
Doreen, I love pansies, but they don't fit the criterion.
Yes: daffodil, marigold, angelica, primrose, bluebell, gardenia, tuberose, fawn lily, foxglove
No: lily, snapdragon, crocus, tulip, nosegay, rose, buttercup, bluebonnet, dandelion, nightshade, petunia, bellflower, dahlia, forsythia, pansy
Any guesses?