Presumably the less invasive hybrid (x cryptica) would be more expensive to buy (illegally on line) since it produces few seeds. My bet would be that anyone selling "Gunnera manicata" on Ebay will probably be offering G.tinctoria, whether they realise it or not, since it reproduces far too readily from seed. I don't know how easy it is to distinguish one species from another. OK, Gunnera isn't a problem in most parts of Britain. However, it genuinely IS a problem in western parts of Ireland (as well as the Hebrides and parts of Cornwall), where it's not killed off by frost in the winter. If you look for photos of gunnera on Achill Island, Mayo, for instance, you'll see how invasive it can be; huge stands of it kill off the natural flora because of its shading effect and because it produces huge amounts of seed. It costs an enormous amount to eradicate.
20 years in a North facing pot... behold the invasion it's almost died a few times and hasn't flowered for maybe 10 years.
