Coulter (1914) on the evolutionary advantage of sex for species

"In conclusion, the impression one obtains of sexuality as a method of reproduction is that it represents protoplasts engaged in reproduction under peculiar difficulties that do not obtain in reproduction by spores or by vegetative multiplication, and that its significance lies in the fact that it makes organic evolution more rapid and far more varied." John Merle Coulter (1914, p. 137: The evolution of sex in plants. The University of Chicago Press)