Eschscholzia.
Easter Lily
iris
I Only Know One flower which is The "Xella"
a flower that starts with N is NARCISSUS
TULIP
tulip
aster
freesia
The grass flower generally have leafy bracts (lemma & palea), hence form a simple flower.
In that sentence, "flower" is the simple subject.
Ursinia is a flower. It begins with the letter U.
Azalea is a showy flower. It begins with the letter a.