What is the name of the male sex cell in plants that fertilizes female flower parts?

The male sex cell in plants that fertilizes female flower parts is known as pollen. Pollen grains are produced in the anthers of flowers and contain the male gametes, which are necessary for reproduction. During fertilization, pollen adheres to the stigma of a flower and germinates, allowing the sperm cells to travel down the style to reach the ovule for fertilization. This process is crucial for the formation of seeds and the continuation of plant species.

In contrast, semen is a term that refers primarily to the male reproductive fluid in animals, not in plants. Ovules are the female reproductive structures that develop into seeds after fertilization takes place when pollen unites with them. Spores are reproductive units in some plants, fungi, and microorganisms, but they are not directly involved in the fertilization process in flowering plants as pollen is. Thus, pollen is accurately identified as the male sex cell responsible for fertilization in plants.