I found a site on the Vitamin A and C content of edible wild plants. Note particularly the Ascorbic Acid content of common Violet leaves and Beta Carotene content of Plantain, both very commonly available wild plants.
Offered by Toni.
Ascorbic Acid and Vitamin A Content of Edible Wild Plants of Ohio and Kentucky
Thomas M. Zennie* and C. Dwayne Ogzewalla
Published in Economic Botany vol 31, pp76-79, 1977.
Fresh samples of 16 wild edible plants were assayed for Ascorbic Acid and 10 plants were assayed for Vitamin A. Many of the plants were found to be rich sources of these vitamins when compared with some common garden fruits and vegetables.
There is a renewed awareness today of the value of natural resources, and this realization ha sled to experimentation with an increased utilization of wild plants as food sources. In some areas of the United States the utilization of such foods is not new. The practice has been handed down through generations and is undoubtedly a carry-over from the times when some pioneers and American Indians subsisted wholely on native foods. Wild spring greens are often available several weeks before garden varieties and are used extensively by individuals familiar with them. Dandelion and wild Asparagus are common foods to some people. Tender Poke greens and Lambs-quarters are consumed in such quantities by some families that they are a standard part of the diet - often being preferred to garden greens. Non-cultivated fruits such as blackberries, blueberries and plums are collected in sufficient quantities to be used in preserving for a winter home supply or for sale on the market. We utilize edible wild plants on a regular basis, and in fact, are delighted when various species are in their prime.
Books on wild edible plants often contain such statements as, "Rose hips are rich in Vitamin C" or " Sassafras leaves are anti-scorbutic" but only a few references have included quantitative analysis of tested wild foods of particular vitamins, minerals and/or other ingredients. Some references are difficult to locate and some do not include details of the assay procedures. At best there is a paucity of information regarding the nutritive values of wild plants, and it is for the purpose of extending the knowledge of vitamin content of commonly consumed wild plants that the study was undertaken.
A selection of wild foods utilized in southern Ohio and northern Kentucky were analyzed for their content of the vitamin A precursor, beta carotene, and ascorbic acid. The plants were chosen because of their availability at the time of the experiment and because their vitamin content was expected to be high. No effect was made to exhaust all the usable species of the area and no effort was made to follow the level of vitamins in the plants through their growing season, although there are values reported for several plants collected at different stages of development.
CONCLUSIONS AND DISCUSSIONS
The carotene values of ten edible wild plants were determined. On a weight basis, six had higher values for carotene than spinach, which is reported to have the highest vitamin A level of the widely marketed garden vegetables. For the following plants - Alliaria officinalis, Capsella bursa-pastoris, Chenopodium album, Chrysanthemum leucanthemum, Glechoma hedaracea, Lactuca scariola, Plantago major, Portulaca oleracea, and Viola papilionacea - each could provide for at least a daily dietary allowance (5,000 units) of vitamin A in a 100 g sample. One collection of Viola papilionacea contained a daily dietary allowance in a 25 g quantity.
The ascorbic acid values of 16 edible wild plants were determined. When compared with oranges, on a weight basis, ten of the wild plants had highervalues of vitamin C: Alliaria officinalis, Allium vineale, Allium tricoccum, Barbarea vulgaris, Capsella bursa-pastoris, Cercis canadensis, Chenopodium album, Duchesnea indica, Oxalis stricta, and Viola papilionacea. Each would provide more than a daily dietary amount of vitamin C in a 100 g sample of the food for an average man or for a woman during pregnancy and lactation (60 mg).
The edible wild plants tested have relatively high carotene or ascorbic acid values or both and could be useful components of the diet, particularly for rural families. Most of the plants are found in abundance in Ohio and Kentucky, and collection of a mess for a family sufficient to provide a daily dietary allowance of the vitamins would be a relatively easy task. Many of the plants may be collected in late winter or early spring when commercial sources of fresh foods may be scarce or expensive and a supply of vitamins from purchased foods may be relatively low. Preferably the plants should be consumed prior to wilting or aging so that the palatability and vitamin content would be high.