The humble orange is not alone, the Colour Pink is derived from a flower.
Wiki has the explanation here http://en.wikipedia.org/wiki/Pink
The color pink is named after the flowers called pinks, flowering plants in the genus Dianthus. The name derives from the frilled edge of the flowers—the verb "to pink" dates from the 14th century and means "to decorate with a perforated or punched pattern" (possibly from German "pinken" = to peck). As noted and referenced above, the word "pink" was first used as a noun to refer to the color known today as pink in the 17th century.