What is the difference between Primary phloem and secondary phloem?

Primary phloem

1. Derived from procambium of apical meristem.

2. District protophloem and metaphloem elements.

3. Sieve tubes long and narrow.

4. Less or no development of phloem parenchyma.

5. Phloem fibres on the outer part.

Secondary phloem

1. Derived from vascular cambium.

2. No clear demarcation between protophloems and metaphloems.

3. Sieve tubes short and wide.

4. Well developed and abundant phloem parenchyma.

5. Phloem fibers among the phloem parenchyma.