Using the scientific name for a white pine, how would you write it as an intergeneric cross?

Using the scientific name for a white pine, how would you write it as an intergeneric cross?

• A. x Pinus strobus
• B. Pinus x strobus
• C. Pinus strobus
• D. Pinus strobus var. septa

Answer: (A)

The idea here is that a hybrid between two different genera is shown by placing the cross symbol before the first genus name. The white pine is Pinus strobus, so an intergeneric cross would be written as × Pinus strobus. This signals that the hybrid involves Pinus and some other genus. Writing Pinus × strobus would indicate a cross between species within Pinus (an interspecific hybrid), which isn’t what the question asks. The other options either omit the cross or mislabel a variety, so they don’t show an intergeneric cross.

The idea here is that a hybrid between two different genera is shown by placing the cross symbol before the first genus name. The white pine is Pinus strobus, so an intergeneric cross would be written as × Pinus strobus. This signals that the hybrid involves Pinus and some other genus. Writing Pinus × strobus would indicate a cross between species within Pinus (an interspecific hybrid), which isn’t what the question asks. The other options either omit the cross or mislabel a variety, so they don’t show an intergeneric cross.