"The majority of species, , and of s are found in the of the Earth. Therefore it is no surprise that the greatest diversity of flower morphologies and plant-pollinator interactions are also present in the tropics. Endress has amassed a splendid display of examples and illustrations of this tremendous diversity. ... ... There are many references to the classic works of , , and , as well as many lesser known but important European workers of the nineteenth century."
January 1, 1970
https://en.wikiquote.org/wiki/W._John_Kress