Perfect: Flowers that have functioning female and male reproductive parts.*
The flowers of this Liriodendron tulipifera (tulip tree) have both male (pollen producing) stamens as well as female (pollen receiving) pistils, they are classified as perfect flowers. Some plants produce separate male and female flowers, each with only male or only female parts, making them imperfect.
Tulip trees are blooming now. You can find one beside the Teaching Garden and another beside the way-finding sign at the west edge of the parking lot.
* Pell, S.K., Angell, B. (2016). A botanist’s vocabulary: 1300 terms explained and illustrated. Portland: Timber Press.