 Although widely and erroneously stated to be rich in vitamin C, most "Rhus" species contain only trace amounts and none should be considered a dietary source of this nutrient.It is high amounts of malic acid that produce the tart flavor.In comparative research, the fruits of "Rhus coriaria" were found to contain the highest levels of ascorbic acid at approximately 39 mg/kg, which would require an adult to consume several pounds daily to reach the US daily dietary reference intake of vitamin C. Sumacs were also cultivated in mishnaic times and are therefore reckoned with those fruits to which the law of "pe'ah" applied (Pe'ah 1