Today, the scientific name for living material that clings to rocks is cryptogamic cover.

今天，附着在岩石上的生材料的学名密。

Scientists have used modern cryptogamic covers to see how the first plants might have worn rocks down 500 million years ago.

科学家们使用现代密了解第一批植如何在 5 亿年前磨损岩石。