Flowers can be complete or bisexual -flowers having all four whorls i.e., Calyx (sepal), corolla (petals), androecium (male -reproductive system) and gynoecium (female reproductive system).
Flower can be incomplete or unisexual-flower having three out of four whorls.
Calyx, the corolla is present but either the male reproductive system is the present or the female reproductive system.
Flowers have a male reproductive system, they are staminate flowers.
Flowers have a female reproductive system, they are pistillate flowers.
Final Answer-
A flower having only a female reproductive system is known as a pistillate flower.