Citrus taxonomy
All of these hybrids have in turn been bred back with their parent stocks or with other pure or hybrid citrus to form a broad array of fruits. Naming of these is inconsistent, with some bearing a variant of the name of one of the parents or simply another citrus with superficially-similar fruit, a distinct name, or a portmanteau of ancestral species. The Ponderosa lemon ("Citrus limon" × "medica") and Florentine citron ("Citrus x limonimedica") are both true lemon/citron hybrids, the Bergamot orange is a sweet orange/lemon hybrid and the Oroblanco is a grapefruit/pomelo mix, while tangelos are tangerine (mandarin)/pomelo or mandarin/grapefruit hybrids, orangelos result from grapefruit backcrossed with sweet orange, and a sweet orange backcrossed with a tangerine gives the tangor. One lumia, a member of the sweet lemons, is the product of crossing a lemon with a pomelo/citron hybrid, though another lumia variety, the Pomme d'Adam, is a micrantha/citron cross, like the Key lime. The most common and commercially popular 'limes', the Persian limes, are Key lime/lemon hybrids that combine the genetic lineages of four ancestral citrus species: mandarin, pomelo, citron and micrantha.
Limey
The term is thought to have originated in the 1850s as "lime-juicer", later shortened to "limey", and originally used as a derogatory word for sailors in the British Royal Navy. Since the beginning of the 19th century it had been the practice of the Royal Navy to add lemon juice to the sailors' daily ration of grog (watered-down rum). The vitamin C (specifically acid) in citrus fruits prevented scurvy , and helped to make these sailors some of the healthiest of the time. At that time "lemon" and "lime" were used interchangeably to refer to citrus fruits. Initially, lemon juice (from lemons imported from Europe) was used as the additive to grog on the Royal Navy ships, but was later switched to limes (grown in British colonies), not realizing that limes did not contain sufficient Vitamin C to prevent the disease.