fallen leaves, leaf litter
その葉っぱは落ち葉だ。
That leaf has fallen off the tree.
庭は落ち葉で覆われていた。
The yard was covered with fallen leaves.
小道に落ち葉が厚く積もっていた。
A thick layer of fallen leaves had accumulated on the path.
歩道は落ち葉で覆われていた。
The sidewalk was covered with fallen leaves.