Branch, pollen grains.

Rose flower is a bisexual flower. Rose plant can be grown by vegetative propagation as well as sexual reproduction.

Vegetative Propagation:

A piece of the branch is properly cut from the parent rose plant, and buried in the soil. Watering it regularly will help in its growth.

Additional Info:

Alternatively, there is a method called bud grafting, where the bud of one rose plant is removed and placed on another plant in a particular way. Then these are held firmly using a rubber band. This technique is mostly used to create hybrid plants.

Sexual Reproduction:

Rose plants can also be grown from seeds. In this method, pollination takes place. The pollen grains would be transferred from anther to stigma of the rose flower. After that, fertilization occurs resulting in the formation of seed. The seed can be dispersed by various agents (e.g., insects). Under suitable conditions, the seed will grow into a new plant.