What is the difference between Protophloem and Metaphloem?

Protophloem

1. First formed phloem.

2. Thin and inconspicuous sieve elements.

3. Sieve areas inconspicuous and absent in gymnosperms.

4. Companion cells absent or present.

5. Element short lived.

Metaphloem

1. Later formed phloem.

2. Wide, long and conspicuous sieve elements.

3. Sieve areas- district.

4. Companion cells –always present.

5. Element-functional for longer period.