Which botanical would contribute a spicy aroma typically associated with ginger and nutmeg?

Calamus is the correct answer because it contains compounds that contribute to a spicy aroma reminiscent of both ginger and nutmeg. This plant, often used in herbal medicine and flavoring, has a distinct fragrance that can evoke these warming, spicy characteristics. The aromatic compounds in calamus are responsible for the spicy notes that can enhance the sensory profile of various spirits.

In contrast, the other botanicals mentioned have different aromatic properties. Pepper, while spicy, typically features a sharp, pungent aroma that is distinct and does not align closely with the sweet spiciness of ginger or nutmeg. Orrisroot is known for its floral, powdery scent, often used as a fixative in perfumery, rather than a spicy aroma. Finally, chamomile has a soothing, herbal fragrance with a sweet, apple-like note, which is far removed from the spiciness associated with ginger and nutmeg.