ruderalis are beautiful because you can grow "low riders" under a stairwell or in a cabinet, and flower a bunch of little foot-tall guys. This makes me think of a question: if the typical binomial nomenclature form is capitalized genus, lower-cased species, lower-cased variety/cultivar, then do you capitalize the species name if you are starting a sentence with it? (eg ruderalis)
Anyway, there is sometimes recognized a fourth variety of cannabis as well, known as afghanica, which is often lumped in with indica, as it has similar characteristics. I however, disagree and think that it is a distinct variety, and perhaps a better expression of the Asian landraces.