Indeed Stephen, this intense dark colouration isn't typical to all types/varities of P. concolor. I had a look in the new book of O. Gruss and there are many fotos but none with such an intense colouration. But who knows ? Nevertheless, this flower is very pretty.
Lovely...and there something nicely strawberry-ish over the colouring of the spots and striation. Actually, the whole flower brings connotations of a yummie vanilla dessert with strawberry syrup on the top, that you really wanna dig into!