Which of the following is the scientific name for Ilex x 'Nellie R. Stevens'?

The scientific name for Ilex x 'Nellie R. Stevens' is indeed Ilex x 'Nellie R. Stevens'. This specific designation includes the 'x' which indicates that it is a hybrid, and the name itself reflects the cultivar 'Nellie R. Stevens'. In botanical nomenclature, the use of single quotes in conjunction with the genus and species is a standard way to denote cultivated varieties or hybrids. Therefore, recognizing the correct format in identifying plant names is essential for accurately communicating about specific cultivars in horticulture and plant sciences.

In contrast, Ilex attenuata, Ilex opaca, and Ilex vomitoria are all separate species within the Ilex genus, but they do not represent the 'Nellie R. Stevens' cultivar. Each of these species has its own unique characteristics and is not synonymous with the hybrid represented by 'Nellie R. Stevens'. Understanding these distinctions helps in proper identification and classification in botanical studies.