Citrus micrantha

The micrantha is a wild citrus from the papeda group, native to southern Philippines, particularly islands of Cebu and Bohol. Two varieties are recognized: small-flowered papeda (C. hystrix var. micrantha), locally known as biasong, and small-fruited papeda (C. hystrix var. microcarpa) or samuyao. Although long viewed as a separate species, C. micrantha, it is now generally viewed to fall within Citrus hystrix, but genomic data on the latter is insufficient for a definitive conclusion. A micrantha was one of the progenitor species of some varieties of lime. ...read more on Wikipedia.