I'm the proud new owner of a Calamandarin from Woodlanders -- so I was looking around to see what I could find on the Net and came across this article on the Sun Chu Sha Kat: http://www.citrusvariety.ucr.edu/citrus_segments.html#sun_chu

I'm having some troubles understanding it though. One -- Is the author saying that Calamandarin and Sun Chu Sha Kat are the same, or that they're very similar, or something totally different? Two -- is he doubting that the Calamandarin really is a cross between the Calamonin and a mandrian? Thanks for helping me sort this out.

Well, I guess I found my answer: "In the Philippines, the calamondin and the different citrus species, except pummelo, are propagated, not by patch budding or cleft grafting, but by shield budding using as rootstocks seedlings of the so-called calamandarin, believed to be a natural calamondin-mandarin hybrid but is actually the sour Cleopatra mandarin."
http://www.wanatca.org.au/acotanc/Papers/Coronel-2/index.htm

So, Calamandarin = Cleopatra mandarin = Citrus reshni

From reading the article I believe that the Cleopatra mandarin is not the same as your Calamandarin, but is only similar

Thanks, Millet. It was a bit confusing for me.

I confess when I first placed the order for this one I had Calamondin in my head -- but as this is a seedling tree, and supposedly fairly hardy, I think I'll stick it next to my C. taiwanica in my orchard (zone 7b) and see what happens.