I Only Know One flower which is The "Xella"
Xanthorrhoea - the Australian grass tree, has a very long, white flower.
Xeranthemum and Xylobium are flowers. They begin with the letter x.
Xanthoceras is a flower. It begins with the letter x.
iris
a flower that starts with N is NARCISSUS
freesia
tulip
aster
TULIP
Ursinia is a flower. It begins with the letter U.
Azalea is a showy flower. It begins with the letter a.
orchid