> Many plants have two different generational types (haploid and diploid).
For the vast majority of plants, these are not physically separate organisms. The key difference here is that the haploid cells of the plant can themselves undergo mitosis, which animal gametes cannot do. Since we generally consider cells with different genetics to be different individuals, we speak of plants as having alternation of generations.
For the most part however, the haploid cells live in the diploid organism or vice versa, depending on which branch of the kingdom you're considering. It's not like botanists run tests on a particular specimen to determine its ploidy. For any given species, we know what the ploidy of the individual is. For example, flowering plants are all diploid. If you find a flowering plant, the individual has two sets of chromosomes, but somewhere in its tissues there is a haploid cell (descended from the parent) that is undergoing meiosis, and is thus a separate organism.
For the vast majority of plants, these are not physically separate organisms. The key difference here is that the haploid cells of the plant can themselves undergo mitosis, which animal gametes cannot do. Since we generally consider cells with different genetics to be different individuals, we speak of plants as having alternation of generations.
For the most part however, the haploid cells live in the diploid organism or vice versa, depending on which branch of the kingdom you're considering. It's not like botanists run tests on a particular specimen to determine its ploidy. For any given species, we know what the ploidy of the individual is. For example, flowering plants are all diploid. If you find a flowering plant, the individual has two sets of chromosomes, but somewhere in its tissues there is a haploid cell (descended from the parent) that is undergoing meiosis, and is thus a separate organism.