Low temperatures

What low temperature (fahrenheit) can a cannabis plant tolerate before serious damage occurs?

This is from "Grow Great Marijuana":
"Temperatures below 50 F will slow growth in most varieties of marijuana. When the temperature drops below 40 F, the plants may experience some damage and require 24 hours or more to resume normal growth. Low nighttime temperatures may delay or prevent bud maturation. Some equatorial varieties (Sativa strains) stop growing after a few 40 F nights."

Thanks! Just the info I was looking for.