All cucurbit embryos analyzed showed a decrease in the ease with which calcium could be extracted from the ash as the ashing temperature increased beyond 600°C. After ashing at 500°C, the Ca in the cucurbit ash was fully extracted by 5% o HC1. After 650°C ashing, lower than expected Ca levels were obtained unless additional ash treatment with HNO3and HC1 was applied. Castor bean embryos plus endosperm showed the same effect but other oily embryos tested did not need ash treatment to fully extract Ca from either the 500 or 650°C ash. Neutron activation analysis indicated that the differences in ash characteristics were related to the differences in concentrations of K and P in the embryo tissues.