Which notation indicates an intergeneric cross in plant naming?

Which notation indicates an intergeneric cross in plant naming?

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

Answer: (A)

The main idea is that a hybrid symbol signals how the cross was made. When the cross is between two different genera (an intergeneric hybrid), the designated hybrid name gets a leading "x" in front of the first genus. So writing the 'x' before Pinus (x Pinus strobus) tells you this name is derived from crossing members of different genera, creating a hybrid genus with the epithet strobus. If the "x" is placed between the names (Pinus × strobus), that format commonly represents a hybrid within the same genus (an interspecific cross within Pinus), not an intergeneric cross. The other options aren’t hybrids or are just a species name, so they don’t convey hybrid status. A real-world parallel is Leyland cypress, written as × Cupressocyparis leylandii, where the leading "×" marks a cross between genera Cupressus and Chamaecyparis, resulting in a hybrid genus Cupressocyparis.

The main idea is that a hybrid symbol signals how the cross was made. When the cross is between two different genera (an intergeneric hybrid), the designated hybrid name gets a leading "x" in front of the first genus. So writing the 'x' before Pinus (x Pinus strobus) tells you this name is derived from crossing members of different genera, creating a hybrid genus with the epithet strobus.

If the "x" is placed between the names (Pinus × strobus), that format commonly represents a hybrid within the same genus (an interspecific cross within Pinus), not an intergeneric cross. The other options aren’t hybrids or are just a species name, so they don’t convey hybrid status.

A real-world parallel is Leyland cypress, written as × Cupressocyparis leylandii, where the leading "×" marks a cross between genera Cupressus and Chamaecyparis, resulting in a hybrid genus Cupressocyparis.