so Arabica is part a species of the Coffea genus often abbreviated to "C. arabica" (Coffea arabica) we know C. liberica and C. canephora (Robusta) but there are many species of the Coffea plant such as C. affinis and C. stenophylla that have black berries or C. tetragona, C. heimii and C dubardii, that are caffeine-free. They are all coffee plants and produce leaves flowers and seeds that broadly look like each other and if roasted, ground and prepared into a drink using whatever desired method can accurately be called "Coffee" and is in no way an adulteration of coffee (like chicory).

Does anyone know what these other coffee species taste like in comparison to Arabica? Catimors very common in coffee and a Catimor is a cross between Robusta and Arabica (more specifically Timor hybrid and Caturra) the goal is to make Coffee more resistant to diseases and there are quite successful crosses that we drink all the time that have done just that and we don't even know about it. Adding another coffee species could potentially make more resistant plants and introduce different flavours in the coffee.

here is an image of C. stenophylla and I'd be interested in what it tastes like.

I understand there hasn't been much interest on the subject but it turns out there has been a growing interest with C. stenophylla and some test farms are cultivating it with the hopes of producing something with a good enough cupping score to compete in the specialty market. Out of interest sake I did some more digging and since the time of writing this thread, perfectdailygrind.com has written a piece on it that can be read here. the scientific research on it feels because of growing concerns over climate change that stenophylla seems like a more viable species to compete and I would think some hybrids with Arabica will come out of this.

I live in Indonesia and there is a robusta plant that is around here that has a purple leaf and black fruit. No one cares about it and lets it grow amongst the other plants then processes them all together. It's some sort of naturally occurring mutation of Robusta and many farms have a couple of them. I'm sure it probably cups like robusta too. But it would be really interesting to get some sort of hybrid between Arabic and this purple robusta variety and pass this purple leaf trait over. The specialty market I think is hitting limits as to what else they can do that's unique and seems to always be looking for improvements or something that stands out. a purple leaf Catimor with black fruit would be pretty interesting so long as the cup quality can be maintained.