树叶掉下之后，留下一些细胞，形成一种被称作维管束痕的小牙。

When dead leaves break away, they leave behind waxy cells that form a small bud called a bundle scar.

youdao

树叶掉下之后，留下一些细胞，形成一种被称作维管束痕的小牙。

When dead leaves break away, they leave behind waxy cells that form a small bud called a bundle scar.

youdao