After seventeen years of work by himself and son, especially upon several species of hieracium, he satisfied himself that his theory was true to the facts.
"A Mechanico-Physiological Theory of Organic Evolution"
Carl Von Nägeli
It is only necessary to see the victory of such drought-resisting weeds as hieracium pilosella, Plantains, Hypochaeris, on lawns to realise how weeds may win in the struggle for existence with the finer grasses.
"Disease in Plants"
H. Marshall Ward