A pound of mushrooms requires less than two gallons of water to grow. That’s a lot less than crops like sweet corn, which uses 148 gallons per pound. A pound of beef soaks up 1,852 gallons. Eating more mushrooms could be a helpful adaptation in a world with dwindling water supplies. That was one of the messages from Dr. Gordon Walker, a mushroom educator who visited Carbondale in April for a talk about his new book, hosted by the Western Colorado Mycological Association. Walker, aka “Dr. Fun Guy” has amassed millions of social media followers of his informational accounts called @fascinatedbyfungi. But Walker said Americans have barely scratched the surface of edible mushrooms’ potential.