There's a genus of plants known as Typha, or cattail. They have seeds like of dandelion, that form thick heads. Such a head may be cut off from the plant and be used for, say, decorative purpose, but when the spring comes, seeds will spread out their 'hairs' and fly away. It looks like an absolutely dry piece of plant - no life in it - suddenly gets alive.
I suggest that it may be a daytime prolongation of a that causes it to spread seeds, but I wonder if anyone knows what sort of cellular/biochemical mechanics is at work here.