Brug Knightii

I've just read --"B. arborea (synonyms Datura arborea , D cornigera" etc etc. Is Knightii a cornigera? And is it then an arborea?

Knightii is a cornigera, - a kind of x candida type with double flowers. I was a little disappointed, when I read this, because I hoped one of these two would be a double arborea. It still tickles my imagination to make a double x flava or a double vulcanicola cross *lol*

Tonny - I read this in Rich Sanders notes on brugs. So if it's a cornigera - is it also an arborea?