Phylloclades - Flat, fleshy, green leaf like structure which has a succession of nodes and internodes at long and short intervals. Leaves are modified into spine or scale to check transpiration. Photosynthesis takes place in phyllacodes. Ex: Opuntia, cereus, Euphorbia

Phylloclades are flat green organs that are modified stems performing the functions of leaves. They are found in certain plants as an adaptation to specific environmental conditions. Phylloclades have several unique characteristics that differentiate them from typical leaves.

1. Definition and Function:
- Phylloclades are modified stems that have evolved to perform the functions of leaves.
- They carry out photosynthesis, transpiration, and other leaf functions.
- The term "phylloclade" is derived from the Greek words "phyllon" meaning leaf and "klados" meaning branch.

2. Morphology:
- Phylloclades are usually flattened, leaf-like structures that resemble typical leaves.
- They lack a petiole (leaf stalk) and have a modified stem that acts as a support structure.
- The phylloclades may be elongated, narrow, or succulent, depending on the plant species.

3. Examples of Plants with Phylloclades:
- Some common examples of plants with phylloclades include members of the genus Opuntia (prickly pear cacti), Ruscus aculeatus (butcher's broom), and certain species of Casuarina (she-oaks).

4. Adaptations and Advantages:
- Phylloclades are an adaptation to arid and semi-arid environments where water availability is limited.
- They help reduce water loss through transpiration as their reduced surface area reduces exposure to the drying effects of the environment.
- Phylloclades also have a waxy cuticle that further minimizes water loss.
- These modified stems can store water, allowing the plant to survive in dry conditions for extended periods.

5. Differences from Leaves:
- While phylloclades perform similar functions to leaves, they have distinct differences.
- Unlike leaves, phylloclades lack axillary buds and therefore cannot form new branches.
- Phylloclades may have stomata on their upper surface instead of the lower surface like typical leaves.

In conclusion, phylloclades are modified stems that have evolved to perform the functions of leaves. They are found in certain plants as an adaptation to arid environments, allowing for reduced water loss and storage capabilities. Examples of plants with phylloclades include prickly pear cacti, butcher's broom, and she-oaks.