What is the correct scientific name for Yucca plants?

The correct scientific name for Yucca plants is represented by the term "Yucca sp." This designation indicates the genus Yucca, which includes several species of perennial plants native to the Americas, particularly associated with arid environments. Using "sp." signifies that this is a general reference to one or more unspecified species within that genus, which covers the entire group of Yucca rather than pointing to a specific type.

The other options provided refer to different genera and species. Schizachyrium scoparium is a species in the genus Schizachyrium, commonly known as little bluestem, which is a grass. Thymus sp. pertains to the genus that includes various species of thyme, a herb, while Rudbeckia sp. refers to the genus containing black-eyed Susans and other flowering plants. Thus, only "Yucca sp." accurately identifies the group of plants known as Yucca.