Talking about Tall Bearded Iris (Iris 'Cloudburst'), Australis wrote:

This Iris must be either a plicata or glaciata, as both its parents are plicatas. The description of an amethyst tint in the centre of the standards indicates that it is almost certainly what is known as a "ghost plicata", where the presence of sufficient anthocyanin inhibitor genes all but makes the plicata markings invisible.

Having just obtained this plant, I hope to flower it and confirm my theory with some test crosses.

Talking about Tall Bearded Iris (Iris 'Claudia Barton Blair'), Australis wrote:

This is a known luminata-plicata and easily shown from its parentage, a luminata x plicata.

Talking about Tall Bearded Iris (Iris 'Matrix'), Australis wrote:

This is an unusual pale plicata which can occur when the anthocyanin inhibitor is present with the plicata pattern. Identified as a plicata in the AIS Bulletin info on Iris Wiki and by hybridiser Chuck Chapman in a post discussing yellow plicatas on hort.net.

Talking about Tall Bearded Iris (Iris 'Suky'), Australis wrote:

Like its parent 'Victoria Falls', 'Suky' definitely carries at least two plicata group alleles (as evidenced by some of its offspring being standard plicatas). Chuck Chapman has hypothesised that it is either 1 luminata allele + 3 glaciata or 2 luminata + 2 glaciata, along with several copies of the anthocyanin enhancement (Ae) gene and one of the anthocyanin inhibitor (I) gene.

Talking about Tall Bearded Iris (Iris 'Victoria Falls'), Australis wrote:

This is an interesting plant genetically, as it definitely carries at least two plicata group alleles (as evidenced by some of its offspring being standard plicatas). It may be that this is an example of the 2 luminata + 2 glaciata genotype, but I am not aware of any crosses to prove this.