What is the scientific name of Leyland Cypress?

The scientific name of Leyland Cypress is derived from its hybrid nature, as it is a cross between two different species of trees. Specifically, the Leyland Cypress is scientifically classified as Callitropsis × leylandii. This name reflects its genetic background, where the "Callitropsis" genus refers to a group of coniferous trees that resemble those in the Cupressaceae family, and the "×" denotes that it is a hybrid. The species name "leylandii" pays homage to the first person to hybridize this tree, therefore making the name accurate and widely recognized in horticultural and botanical communities.

In contrast, the other names listed pertain to different tree species entirely. Cedrus atlantica 'Glauca' refers to the Atlas cedar, a distinct species known for its blue foliage. Cedrus deodara is commonly known as the Deodar cedar, which is also not related to the Leyland Cypress. Lastly, Carya illinoinensis refers to the pecan tree, which belongs to a completely different plant family and has no relation to conifers. This clear distinction showcases why the correct scientific name for Leyland Cypress is Callitropsis × leylandii.