i would question the use of the term "proper" for "place of origin", but it is true that many seeds can remain viable, far longer then the life of their host, until fertilized and becoming hosts themselves. also flowers are not themselves seeds. also this is different for animate life forms from that of vegatative ones. there are also the "seeds" of planets and solar systems to consider. these are somewhat less well understood. (the real wisedom, (as ted sturgeon once pointed out) is to always ask (yourself) the next question)