The plant may have been a castor-bean plant (Ricinus communis), which grows rapidly in hot climates to a height of 12 feet and has large leaves. – J.D. Hannah
 Hannah, J. D. (1985). Jonah. In J. F. Walvoord & R. B. Zuck (Eds.), The Bible Knowledge Commentary: An Exposition of the Scriptures (Vol. 1, p. 1471). Wheaton, IL: Victor Books.