Which term describes a flower that is missing one or more whorls?

The term that describes a flower missing one or more whorls is "incomplete flower." A whorl in a flower refers to the arrangement of its parts, which typically include the sepals, petals, stamens, and carpels. When a flower is classified as incomplete, it lacks one or more of these essential structures. This can occur in various flower types, and understanding this classification helps in distinguishing between different forms of flowering plants.

In contrast, a perfect flower has both male (stamens) and female (carpels) reproductive structures, making it complete in terms of sexual organs, but it may still lack other parts such as petals or sepals. An imperfect flower, on the other hand, is one that has either male or female reproductive organs, but not both. The term "simple flower" does not pertain specifically to the presence or absence of whorls—it usually describes a flower structure that is not compound or complex. Thus, the classification of an incomplete flower focuses specifically on the absence of certain whorl structures, making "incomplete flower" the correct term in this context.