Male and female gametophytes in Cedrus do not have a free-living independent existence.

Explanation:

Cedrus is a gymnospermic plant that belongs to the family Pinaceae. It is commonly known as cedar. The life cycle of Cedrus is a typical gymnospermic life cycle that involves the alternation of two generations, sporophyte, and gametophyte.

The gametophytes of Cedrus are haploid and they are produced from the spores of the sporophyte. The male gametophyte is represented by a small pollen grain that contains two sperm nuclei. The female gametophyte is represented by the embryo sac that contains a single egg cell and two synergids.

Unlike other gymnospermic plants, the male and female gametophytes of Cedrus do not have a free-living independent existence. They are completely dependent on the sporophyte for their survival and development. The male gametophyte develops within the microsporangia of the male cone and it is released in the form of pollen grains. The female gametophyte develops within the ovules of the female cone and it remains attached to the sporophyte until fertilization occurs.

During fertilization, the pollen grain lands on the receptive surface of the female cone and releases the sperm nuclei that fuse with the egg cell and the synergids to form the zygote and the endosperm. The zygote develops into the embryo and the endosperm develops into the nutritive tissue that supports the growth of the embryo.

Therefore, it can be concluded that Cedrus is the only plant among the given options in which male and female gametophytes do not have a free-living independent existence.

Cedrus is a gymnosperm having reduced dependent gametophytes- pollen and endosperm. In gymnosperms the male and the female gametophytes do not have an independent free-living existence and remain within the sporangia and are retained on the sporophytes.