In a classic study by H.J. Dittmer, a single rye plant -- a kind of grass -- growing about 20 inches high and consisting of a clump of about 80 shoots, was found to have 380 miles of roots, and this included 14 billion root hairs! If all these root hairs had been split open and spread flat on a floor, their combined surface area would have covered more than 4,000 square feet -- about the floor space occupied by two or three good-sized houses. All this root-hair surface-area was absorbing water for that single clump of grass... No wonder rye can grow in fairly dry soil!