A typical foliage leaf of a plant belonging to the dicotyledons is composed of two principal parts: blade and petiole.

双子叶植物典型的营养叶由两个主要部分组成：叶片和叶柄。

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It was a sweet substitute for the yet absent murmur of the summer foliage, which drowned that music about the Grange when the trees were in leaf.

这美妙的声音代替了现在还没有到来的夏日树叶飒飒声，等到树上生了果子，这声音就湮没了田庄附近的那种音乐。

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He theorizes that clematis wilt isn't simply a fungal infection, but a failure of the stems to carry enough water to the foliage when the plants are in full leaf and the weather is stressful.

他提出，铁线莲枯萎病并非简单的真菌感染，而是当植株长满叶子并且天气恶劣时，茎干未能成功运送足够的水分到叶。

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When in leaf it's easier to spot because it seems as if the foliage has been damaged by a severe frost and turns limp and black.

BBC: The heartbreak of watching the slow death of ash trees

Invisible and, often odorless, green leaf volatiles emitted from vegetation act as a defense mechanism, communicating to other foliage that danger is near.

ENGADGET: Chemical sensors could detect plants' cries for help, reduce need for pesticides