Final answer:
A flower without an anther cannot produce pollen. A flower lacking the androecium is called pistillate or carpellate, and one missing the gynoecium is staminate. Flowers without a megasporangium cannot produce megaspores, and those without a microsporangium can't produce microspores.
Step-by-step explanation:
Flower Reproductive Structures and Their Terminology
When a flower is missing its anther, it is unable to produce pollen, which contains the male gametes necessary for reproduction in flowering plants. Without the anther, the male structures of the flower, collectively known as the androecium, are incomplete. The term used to describe an incomplete flower lacking the androecium is pistillate or carpellate, indicating that the flower only contains the gynoecium, the female reproductive parts. Conversely, a flower that lacks the gynoecium, specifically the components such as the ovary, style, and stigma, is referred to as staminate. These staminate flowers contain only male reproductive structures and are unable to produce the female gametes.
Moving further into the structural components of the flower, the megasporangium is responsible for producing female gametes. If a flower lacks a megasporangium, it would not be able to form the megaspore, which eventually gives rise to the female gametophyte. On the other hand, if the flower lacked a microsporangium, it would be unable to form the microspores that develop into pollen grains containing the male gametes.
A flower that has both the androecium and gynoecium is termed perfect, androgynous, or hermaphroditic, as it can potentially self-fertilize or contribute to fertilization with another flower. These terms are essential for understanding the reproductive capabilities of flowers and the potential impact of missing reproductive structures on plant reproduction.