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.
Citrus taxonomy
Australian and New Guinean citrus species had been viewed as belonging to separate genera by Swingle, who placed in "Microcitrus" all but the desert lime, for which he used "Eremocitrus". However, genomic analysis shows that though they form a distinct clade from other citrus, this is nested within the citrus phylogenetic tree, most closely related to kumquats, suggesting that all these species should be included in the genus "Citrus". Wu, "et al.", found that several of the finger lime cultivars were actually hybrids with round lime, and concluded there were just three species among those tested, desert lime ("C. glauca"), round lime ("C. australis") and the finger lime ("C. australasica"), though their analysis did not include other types previously identified as distinct species. In more limited genomic analysis, the New Guinea wild lime, "Clymenia" and "Oxanthera" (false orange) all cluster with the Australian limes as members of "Citrus". The outback lime is a desert lime agriculturally-selected for more commercial traits, while Some commercial varieties of the Australian lime are hybrids with mandarins, lemons, and/or sweet oranges. "Clymenia", will hybridize with kumquats and some limes.