Hippeastrum vittatum is a very well-known species that also presents a great deal of confusion as far as its origins are concerned. I always try to find out the origins and habitat of a species when I grow it, otherwise you are left guessing as to what kind of conditions it needs. H. vittatum is described as A) being from Peru; B) being from Argentina; C) being from Bolivia and D) being from Brazil!! It is also described as being a hybrid, not a species.
I think the confusion arises from the fact that it was collected in Peru but it was in cultivation there, and is not native to that country. I have no idea why Brazil and Argentina got into the act, since it was collected in the 1800's in Bolivia, and described as native to Bolivia. It has been used extensively as a parent in creating hybrids, so some bulbs that are circulated as H. vittatum hybrid have also added to the confusion, leading people to believe that it wasn't a pure species at all.
There is a great deal of variation in this species, especially as to the proportions of red and white in the petals. I have two accessions, both grown from seed, one of which has much more red than the other. Some have even more red, with only a small amount of white striping. They are all lovely. I grow mine in Mix #1, and do not provide extra heat.