First I noticed that I said for this pattern "with
stripes that are light on a dark background". This is technically
not correct, but this is how they appear. The dark coloring is in the
spaces between the major veins, and makes it look as if the veins are represent
as pale stripes on a darker ground. However, the light color is still
the ground or underlying color.
I've been getting mixed signals on definition of luminata for
some time, and there seem to be two slightly overlaping definitions. I'm
not sure either one is addopted as "official" anywhere. One, the first
below, is what I would consider a mixed and incorrect definition, but is
One; rather artificial; includes anything with the outer part of the falls
dark, fading to a contrasting pale zone around the beard. This includes
diverse types of pattern, true luminatas, true plicatas, a mix of the
two in one flower, etc. It is indeed purely a visual definition, and
has little to due with the actual structuring of the pattern. I do not
believe this is the true definition of a luminata, but it is the one most people
seem to use.
Two; a pattern with dark coloring lying over a lighter ground and
located primarily between the major veins. Usually this is most strongly
represented on the falls, but not exclusively so, and most often strongest
somewhere away from the base of the petaloids. The distribution of the
pattern can actually be anywhere on the petaloid though, sometimes even
concentrated near the hafts (as in 'Fast Track'). Most often the basal
area around the beard is lighter and looks like a bright light colored signal;
also, usually the margin of the petaloid is lighter (in varying degrees).
This is sort of the reverse or compliment pattern to plicata, but the two often
look grossly rather similar. Plicata is commonly more strongly developed
near the base and the margins of the petaloids, and the dark pigment is
concentrated along the veins. Often the two patterns occur together in the
same flower. In some cases it is possible for a plicata plus luminata
pattern to compliment each other to the point of entirely masking out the
lighter ground below, though I don't know how often this actually occurs.
By this definition, many plicatas appear in catalogs as luminatas and even
registered as such, and the reverse is true as well.
I consider number two to be the true definition of a luminata.