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.