Sympetalous: With the petals united, at least near the base.*

Plants such as petunias (Petunia spp.), Calibrachoa, morning glories (Ipomoea spp.), flowering tobacco (Nicotiana spp.), and many others all have sympetalous blooms.

*Harris, J.G., Harris, M.W. (2001). Plant identification terminology: An illustrated glossary (2nd ed.). Spring Lake: Spring Lake Publishing.