This form of Japanese yew was introduced by Monrovia in 1987. It was discovered as a sport of T. cuspidata, a native of Japan, Korea and Manchuria. Taxus is a genus of woody trees and shrubs which falls into the Taxaceae family. The genus contains eight species all native to the Northern Hemisphere. The species was introduced into the United States by Dr. George R. Hall who sent plants from Shanghai. From these first introductions into Europe and the US came a variety of new yews often listed as Taxus x mediacultivars. 'Monloo' produces a female-clone type flower.
All species of this genus are poisonous. One American species is the source of the cancer drug, Taxol. In England yew trees were restricted to church yards where they were not subject to livestock grazing, which caused many animal deaths in the past.