I have not seen or heard of a red
Bacopa. There is a
Bacopa pink and
Bacopa araguaia is more of a purple color. Note that
Bacopa araguaia is a very different plant from
Bacopa sp araguaia, visit
this thread for more info.
"Bacopa araguaia" isn't a valid species name. If it were, it would be something like "araguaiensis". There are also no records of a species with that name. I think that in that other thread, you've got two species with similar or the same trade name that may be from the same general area. That's not unheard of. I suspect the purple one is what's known as 'colorata' but doctored up or with funny color balance, etc. Either that, or it's something new with really, really weird coloration.
Rotala sp. 'Araguaia' was introduced as a
Bacopa. It obviously isn't, and that seems to be generally accepted by now. That's the plant to which yosko is referring.
The
Bacopa sp 'Araguaia' that's been in the hobby here is similar to B. caroliniana but has a distinct marking down the middle of the leaf, which has a slightly different shape. I'll see if I can dig up a picture later.
