Fukushu Kumquat

Fukushu is also called Changshou and Choju. The UCR account says it is considered a chance hybrid between two Fortunella species and attributes that hypothesis to Swingle; the cultivar’s actual origin and parents are not established by that account.^⁠[1]

UCR records receiving the CRC 3475 accession as seed from Okitsu, Shizuoka, through W. P. Bitters in 1963; this is accession history, not evidence that the cultivar originated then. Its Riverside account describes a small, spreading, thornless tree with broader leaves and relatively large fruit with a thin orange rind, acidic flesh, and a depressed tip. UCR lists year-round ripening at Riverside.^⁠[1]

UCR's records give differing fruit descriptions: the 1963 note describes smooth, bell-shaped fruit with 8–10 seeds, while another description calls the fruit oval with a depressed apex and few seeds. These are observations recorded in different accounts, not a fixed seed count or shape.^⁠[1]

Individual grower samples also vary: one report describes low juice and pithy flesh in some fruit from a young tree, while another describes its greenhouse sample as very juicy. Separate tasters report anything from one tiny seed to a fairly large seed. These are sample-specific observations, not cultivar-wide measurements.^{⁠[4]⁠[7]⁠[13]⁠[14]}