The clementine is a spontaneous citrus hybrid that arose in the late 19th century in Misserghin, Algeria, in the garden of the orphanage of Brother Clément Rodier, for whom it would be formally named in 1902. Some sources have attributed an earlier origin for the hybrid, pointing to similar fruit native to the provinces of Guangxi and Guangdong in present-day China but these are likely distinct mandarin hybrids, and genomic analysis of the clementine has shown it to have arisen from a cross between a sweet orange (Citrus × sinensis) and the Mediterranean willowleaf mandarin (Citrus × deliciosa), consistent with Algerian origin. There are three types of clementines: seedless clementines, clementines (maximum of 10 seeds), and Monreal (more than 10 seeds). Clementines resemble other citrus varieties such as the satsuma and tangerines. Clementines differ from other citrus in having lower heat requirement, which means the tolerance to fruit maturity and sensitivity to unfavorable conditions during the flowering and fruit-setting period is higher. However, in regions of high total heat, the Clementine bears fruit early; only slightly later than satsuma mandarins. These regions such as North Africa, Mediterranean basin, and California, also favor maximizing the Clementine size and quality. As a result, the tastiest Clementines are from these hot regions.