If you send her buttercups, it means:

• Childishness

Genus: Ranunculus

There are over 400 species of buttercups. All Ranunculus species are poisonous, when eaten, to mammals. However, at the very base of their petals there's a cuplike scale where insects will find a  nectar.

When Ranunculus plants are handled, naturally occurring ranunculin is broken down to form protoanemonin, which is known to cause contact dermatitis in humans and care should therefore be exercised in excessive handling of the plants. The toxins are degraded by drying, so dried buttercups are safe.

An old superstition says that if you hold a buttercup under your face, and yellow light is reflected on your face, it means that you like butter.