A fast-spreading fungus is ravaging the world's rubber trees. But thanks to researchers at Germany's Fraunhofer Institute for Molecular Biology and Applied Ecology, there's now an alternative: dandelions. Scientists have long known that the weed's sap contains latex, but it's difficult to harvest because dandelion ooze polymerizes — goes gummy — when it hits the air. The Fraunhofer team overcame that sticky problem by switching off a key enzyme. The new, improved dandelion produces 500% more usable latex than the old weed does.