Vitamin C in Plants: Iris (Iris germanica)

Abstract

THE communications that have appeared in NATURE during the past few years in which rose hips, pine needles, etc., have been suggested as sources of vitamin C, prompt me to direct attention to the leaves of the common European iris (Iris germanica) as a superior material from which this vitamin can be readily prepared in substantial quantity. Unlike fruits, the ascorbic acid of which increases as they ripen, the leaves of most plants contain the largest amount when young¹; most of the vitamin rapidly disappears from leaves as the plants mature. With Iris, however, the ascorbic acid content of fresh undried leaves, which is 0·6 per cent in the spring, does not fall below 0·3 per cent as the season advances. Few plant materials contain as high a concentration as that found in Iris leaves even at the end of the season (at least in the vicinity of New York City). The leaves are heavy and can be cut with little injury to the root-stalks. The vitamin is separated from the gums and other substances present in press juice far more easily than from any other source we have used².