Bracken fern has been spreading from its woodland strongholds for centuries, but the rate of encroachment into open countryside has lately increased alarmingly throughout northern and western Britain.

• 欧洲蕨已经从其大本营林地向外蔓延几个世纪了，但在英国的北部和西部，欧洲蕨最近向田野蔓延的速度却快得惊人。