An aldohexose sugar. Obtained from leaves of Protea rubropilosa: Beylis, Perold, Chem. Commun. 1971, 597. Prepd by reduction of d-allonic lactone with sodium amalgam: Levene, Jacobs, Ber. 43, 3147 (1910). Synthesis: Hughes, Speakman, J. Chem. Soc. 1965, 2236; Baker et al., Carbohydr. Res. 24, 192 (1972).