This is the most important, by far, of all petitgrain oils. The oil is produced in Paraguay and, to a smaller extent, in Haiti. However, only in Paraguay is the oil distilled exclusively from the bitter sour variety of Citrus Aurantium, subspecies amara, the bitter orange tree. This tree grows wild, serniwild and is cultivated on a large scale in the interior of Paraguay. tsca definition 2008: extractives and their physically modified derivatives. citrus vulgaris, rutaceae.