Plant Skulls

If you didn’t know this was a plant science blog, you might think these were macbre trophies of some ancient tribe. This isn’t so much an appropriate plant costume for Halloween as it is an interesting confluence of floral anatomy and human propensity for recognizing facial forms.

Snapdragons or Antirrhinum sp. are a colorful staple of summer gardens. We’re more used to seeing them look like this image with tall inflorescences boasting clusters of ruffled flowers in a variety of color schemes.

Antirrhinum majus Credit: Michael Apel via Wikimedia Commons

What’s responsible for this spooky transition from delicate flowers to haunting faces? It all comes down to the snapdragon’s flower structure and its bilateral symmetry. The skulls are really the seed pods of the plant after the flowers have been pollinated and the petals have withered away. Dissecting the flowers in their prime shows the ovary at the base of the bloom. The pollen-containing stamens and the style emerge from the orifices in the ovary. These structures leave behind gaping holes that look like a mouth and eye sockets.

Snapdragon flower anatomy

The striking resemblance of these seed pods to human skulls has led to their association with supernatural powers. They were purported to help women stay young and beautiful as well as protect humans of all ages from witchcraft and evil spirits. I don’t have any scientific evidence of that, but if you’re looking for new ideas for botanical Halloween decorations that go beyond cucurbits and mums, dried snapdragon stems with seed pods make a wicked wreath.