Stems modified into flat green organs performing the functions of leaves are known as:

Stem modified into flat green organs performing the functions of leaves are known as phylloclades whereas phyllode is a modification of petiole. Cladode is a flattened organ arising from the stem of a plant. These often replace the leaves in photosynthetic function, as leaves in such plants are typically reduced to scales. Example: Asparagus, butcher's broom. Scale is a modified thick and fleshy leaf.