In 1960 a photograph of trichomes on the leaves of Lesquerella ovalifolia Rydb. appeared on the cover of Science (6); they were reported to be highly refractive. Lanning (1) analyzed trichomes from Lesquerella ovalifolia plants that grew wild in Scott and Sheridan counties in western Kansas. The trichomes were found to be 27.0 percent calcium carbonate and the ash of the trichomes was 87.7 percent calcium carbonate. The leaves without trichomes contained only 2.25 percent calcium. This is about average for leaves of many of the Cruciferae. An x-ray diffraction pattern of the powdered trichomes showed the sharp peaks characteristic of calcite. In addition it showed cellulose and small quartz peaks (detrital). The present investigation was made to determine the calcium content of the other plant parts and to determine variations in ash and silica contents occurring between the various parts of the Lesquerella ovalifolia plant. Previous work by Lanning and co-workers (2,3,4,5) has shown that wide variations in mineral contents do occur between various parts of the same plant. Plants from four different locations were studied in order to determine truly significant variations in the plant.