And in Montpelier, France, it's taken fewer than 12 years for urban weeds to start producing a larger proportion of heavy seeds, boosting their odds of settling in a patch of nearby soil instead of crash-landing on concrete.

而在法国的蒙特利埃，在不到 12 年的时间里城市的杂草就开始播撒大量重量更重的种子，以提高它们在附近的土壤中生根的机会，而不至于飘落到钢筋混凝土的路上。