Additional distinctive features: 
This flower was found in Antrim Park next to a river off the walkway.
It is on page 120 in Newcomb’s Wildflowers.
Common name Northern Blue Flag. Scientific name: Iris versicolor
Corolla: 6 fused petals.
Calyx: 6 fused sepals.
Adroecium: number of stamens 3 separate stamen.
Gynoecium type: syncarpous (and # of carpels = 4)
How can you tell? (Cite the features were apparent about the number of carpels.)
Flower type/ovary position: epigynous
Flower symmetry: zygomorphic (irregular).