Recently, Carla posted about tumbleweeds invading Victorville, California leading to numerous 911 calls. Why do tumbleweeds tumble though? To make more tumbleweeds of course. From KQED's Deep Look:
Starting in late fall, (tumblweeds) dry out and die, their seeds nestled between prickly dried leaves. Gusts of wind easily break dead tumbleweeds from their roots. A microscopic layer of cells at the base of the plant — called the abscission layer — makes a clean break possible and the plants roll away, spreading their seeds. When the rains come, an embryo coiled up inside each seed sprouts.
