John Harvey Kellogg,
Plain Facts for Old and Young
“ When the male and female parts of flowers are situated on different plants, as is the case in the willow, the poplar, the melon vine, and many other species, the pollen of the male flower is wafted by the wind or gentle breeze to the stigma of the female flower, which will usually be found at no very great distance, although fertilization may take place in this way at very considerable distances. ”
