What term describes a specific type of plant developed and maintained under cultivation?

The term that specifically describes a type of plant developed and maintained under cultivation is "cultivar." This designation is used to identify plants that have been intentionally selected for certain characteristics through cultivation and breeding practices. Cultivars are often distinguished by particular traits such as flower color, size, growth habit, or disease resistance, which are consistent enough to be recognized and propagated.

In horticulture, cultivars are a vital part of plant classification, as they indicate not only the genetic makeup of the plant but also its intended use or aesthetic appeal in landscape design. The term itself is a contraction of "cultivated variety," highlighting the fact that these plants have been cared for and refined by humans. This is why the term "cultivar" is most appropriate in this context, as it encapsulates both the human influence in the plant's selection and its specific identity as cultivated.