Yep, that's them. There are hardy, tropical and subtropical species, found all over the world. The one you are thinking of is probably Aristolochia macrophylla (A. durior), a deciduous plant which is native to Eastern North America. I've never seen that one.
The ones I've grown are cold sensitive (zone 9b+) with the exception of A. fimbriata (zone 7, I think).
A friend grows a different hardy one (zone 5, I think) from Europe: Aristolochia baetica. He says it blooms all year for him, in California's Central Valley.
The Wikipedia article on Aristolochias is nice, with a surprising number of photos of different species. There are even tree forms, such as Aristolochia arborea:
en.wikipedia.org
The ones I've grown are cold sensitive (zone 9b+) with the exception of A. fimbriata (zone 7, I think).
A friend grows a different hardy one (zone 5, I think) from Europe: Aristolochia baetica. He says it blooms all year for him, in California's Central Valley.
The Wikipedia article on Aristolochias is nice, with a surprising number of photos of different species. There are even tree forms, such as Aristolochia arborea:

Aristolochia - Wikipedia
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