Taiwanica Lemon

Fruit medium-large, obovate; broadly necked and narrowly collared; seedy. Rind medium-thick but easily peeled; somewhat pebbled; prominent sunken oil glands; color lemon-yellow. Sections 10 to 12 and axis open. Flesh color dull yellow; juicy; acid flavor with bitter aftertaste. Seeds large, slimy, with wrinkled seed coat, and polyembryonic.^⁠[1]

Tree vigorous, upright-spreading, and very thorny. Foliage consists of medium-large, somewhat slender, light green, sharp-pointed, strongly winged leaves, the oil of which is suggestive of bitter orange.^⁠[1]

UCR records Taiwanica as Nansho Daidai (CRC 2588, PI 539680), with parents unknown, and documents receipt of the accession via W.T. Swingle in 1935. A separate Forestry Agency account reports the species-level discovery of Citrus taiwanica in 1926 at Hongmaoguan; it does not establish this accession’s origin.^{⁠[1]⁠[12]}

The juice has been used diluted and sweetened, and Taiwanese producers also make marmalade from the fruit. Cold-weather reports vary: one small plant in Switzerland regrew after roughly −11 to −13°C despite losing all its leaves and some branches, while other growers report repeated dieback or death. These individual reports do not establish a reliable minimum temperature for every plant sold as Taiwanica.^{⁠[14]⁠[12]⁠[16]⁠[15]}