Papeda orpapaeda is the common name for a group ofCitrus species and varieties native to tropical Asia that are hardy and slow-growing, and produce unpalatable fruit.Walter Tennyson Swingle segregated these species into a separate subgenus,Papeda, that included theIchang lemon,yuzu,kaffir lime,kabosu,sudachi, and a number of wild and uncultivated species and hybrids. Recent genetic analysis shows the papedas to be distributed among distinct branches of theCitrus phylogenetic tree, and hence Swingle's proposed subgenus ispolyphyletic and not a valid taxonomic grouping, but the term persists as acommon name.[citation needed]
Because of generally slow growth and bitter, less palatable fruits than in other citruses, papeda species have only limited commercial cultivation. Some species, like ichang papeda, are used inlandscaping, while others are important forrootstocking and as genome source for breeding disease-resistant and frost-hardy citrus hybrids.[1] In some cases the skin or leaves are used as a flavoring in Asian cuisine.[citation needed]
It is believed, based on molecular studies, that thecitron,pomelo,mandarin and papedas were the ancestors of most hybrid citrus species and their varieties, which resulted from breeding or naturalhybridization among the parental species.[2] For example, theKey lime, a hybrid between a papeda, themicrantha, and a citron, has in turn given rise to many commercial types of limes.[citation needed]
There are four species of Papeda currently recognised byKew and theMissouri Botanical Garden.[3]These are:
There are many naturally occurring varieties that are now classified as subspecies:
A number of hybrids between this subgenus and the subgenusCitrus also exist:
