Yellow flowers and leaves of turmeric, Curcuma longa (Zingiberacea), aromatic herb, spice.. Color-printed woodblock engraving by Kan'en Iwasaki from Honzo Zufu, an Illustrated Guide to Medicinal Plants, 1884. Iwasaki (1786-1842) was a Japanese botanist, entomologist and zoologist. He was one of the first Japanese botanists to incorporate western knowledge into his studies.