Moroccan citron
The Moroccan citron was described by the Moroccan professor Henri Chapot, as being a sweet citron, meaning that its pulp is low in acid. He discovered that the acidity in the more common citrons or lemons, is represented by red on the inner coat of seeds specifically on the chalazal spot, violet pigmentation on the outer side of the flower blossom, and also by the new buds that are reddish-purplish. The Moroccan citron which is acidless is completely lacking the red color. This designation was cited by Herbert John Webber and Leon Dexter Batchelor the editors of the fundamental treatise on citrus, namely The Citrus Industry, which was published by the University of California, Riverside in 1967.
Citron
The citron is thought to have been native to India, in valleys at the foothills of the eastern Himalayas. It is thought that by the 4th century BC, when Theophrastus mentions the "Persian or Median apple", the citron was mostly cultivated in the Persian Gulf on its way to the Mediterranean basin, where it was cultivated during the later centuries in different areas as described by Erich Isaac. Many mention the role of Alexander the Great and his armies as they attacked Persia and what is today Pakistan, as being responsible for the spread of the citron westward, reaching the European countries such as Greece and Italy.