megistotherm
/mɪˈɡɪstə(ʊ)θəːm/Ecology (now historical and rare )
noun
A plant requiring a mean annual temperature of more than 30 degrees C.
Origin
Late 19th century; earliest use found in Nature: a weekly journal of science. From French mégistotherme from ancient Greek μέγιστος + French -therme.