Common stork's-bill, Aguja de pastor

Herbaceous annual, and in warm climates a biennial member of the Geranium Family of flowering plants.
Hairy, sticky. The stems bear bright pink flowers, arranged in loose cluster, and often have dark spots on the bases. The leaves are pinnate and fern-like, and the long seed-pod, shaped very much like the bill of a stork, bursts open in a spiral when ripe, sending the seeds (which have little feathery parachutes attached) into the air.

Seed launch is accomplished using a spring mechanism powered by shape changes as the fruits dry. The spiral shape of the awn can unwind during daily changes in humidity, leading to self-burial of the seeds once they are on the ground. The two tasks (springy launch and self-burial) are accomplished with the same tissue (the awn), which is hygroscopically active and warps upon wetting and also gives rise to the draggy hairs on the awn.

Common stork's-bill can be found in bare, sandy, grassy places both inland and around the coasts. It is a food plant for the larvae of the Brown Argus butterfly.