Dermatogen is the region or histogen of single layer of outermost cells formed from the apical meristem . dermatogen gives rise to epidermis of stem and other aerial parts . periblem is the middle histogen which forms the cortex of stem and roots. plerome is the central histogen which forms stele or part of stem and root inner to endodermis . part of plerome that forms vascular tissues is called procambium . the Pericycle layer converts into a secondary meristem called cork cambium or phellogen which divides to form secondary cortex or phelloderm

The correct answer is option 'B', plerome.

Vascular tissues in flowering plants, also known as angiosperms, develop from the plerome. The plerome is one of the three primary meristems present in the growing tips of the plant. It is responsible for the formation of the vascular tissues, which include xylem and phloem.

Below is a detailed explanation of the development of vascular tissues in flowering plants:

1. Meristems:
- Meristems are regions of actively dividing cells in plants.
- The growing tips of plants contain three primary meristems: dermatogen, periblem, and plerome.

2. Dermatogen:
- The dermatogen gives rise to the epidermis, which is the outermost protective layer of the plant.
- It differentiates into various specialized cells, such as trichomes, stomata, and cuticle.

3. Periblem:
- The periblem gives rise to the cortex, which is the region between the epidermis and vascular tissues.
- It differentiates into parenchyma cells that provide support to the plant and store nutrients.

4. Plerome:
- The plerome is the innermost primary meristem and is responsible for the development of vascular tissues.
- It differentiates into two types of vascular tissues: xylem and phloem.

5. Xylem:
- Xylem is responsible for the transport of water and minerals from the roots to the rest of the plant.
- It consists of several types of cells, including tracheids, vessels, fibers, and parenchyma.
- These cells are dead at maturity and form continuous tubes for efficient water transport.

6. Phloem:
- Phloem is responsible for the transport of organic nutrients, such as sugars, from the leaves to other parts of the plant.
- It consists of sieve elements, companion cells, fibers, and parenchyma.
- Sieve elements are responsible for the translocation of sugars, while companion cells provide metabolic support.

In conclusion, vascular tissues in flowering plants develop from the plerome, which is one of the primary meristems present in the growing tips of the plant. The plerome gives rise to the xylem and phloem, which are responsible for the transport of water, minerals, and nutrients throughout the plant.