The Mistletoe's Relations

In the case of the misseltoe, which draws its nourishment from certain trees, which has seeds that must be transported by certain birds, and which has flowers with separate sexes absolutely requiring the agency of certain insects to bring pollen from one flower to the other, it is equally preposterous to account for the structure of this parasite, with its relations to several distinct organic beings, by the effects of external conditions, or of habit, or of the volition of the plant itself.

A parasite is never just one relationship. Darwin picked the mistletoe to show that a single plant could need a tree, a bird and an insect all at once, and that no theory of mere habit could explain it.

Source: Charles Darwin, On the Origin of Species, 1st ed. (London: John Murray, 1859), Introduction, p. 3. Text: Project Gutenberg. Public domain in the US. Pairs with: Wands (parasitic plants): Ace or Page of Wands A note from 2026: Mistletoe is a hemiparasite: it makes its own sugar and takes water and minerals from the host. Not every mistletoe has separate sexes or insect pollinators, though European Viscum album has both.

Public domain in the United States.