Oh my! Mindboggling!
I am afraid you lost me when it come to a cross between a graft-chimarea and
a non-chimaera. What is the view we should take of the pollen of a
graft-chimaera? (this is the relevant factor, IIUIR?)
PvR

Stewart Robert Hinsley schreef
The following is speculation.

Many plants have 3 layers of tissue in the meristem.

Lavatera x clementii 'Rosea' is non-chimaeric, and has rose-coloured
petals with a rose-red eye. Let us denote the composition of the 3
layers in this cultivar as RRR.

Lavatera x clementii 'Barnsley', to the best of my knowledge, is a sport
of 'Rosea'. It has flowers that open white, with the same rose-red eye.
The flowers turn pink as the age. It is known to be a periclinal
chimaera, and also is observed to have a propensity to revert to a rose-
flowered state. Let conjecture, for reasons which should become clear,
that the composition of the 3 layers is WRR.

Lavatera x clementii 'Blushing Bride', to the best of my knowledge, is a
sport of 'Barnsley'. The flowers age to a slightly paler pink than
'Barnsley', and it does not have the same tendency to revert. (I've seen
one source that says that this variety to not change colour as it ages,
but consider the cultivar name, I'm confident that that source is in
error.) I conjecture that this is WWR.

There are cultivars with similar flowers which don't turn pink with age,
which would be WWW. 'Lisanne' is, I believe, a cross between Lavatera
thuringiaca 'Ice Cool' (which has pure white flowers, including the eye)
and 'Barnsley' - I have been told that it's a sport of 'Barnsley', but
the habit differs, and is similar to the supposed seed parent, so I find
that explanation more convincing. 'Memories' (aka 'Stelav') also has a
compact habit, and may be a similar cross.

It may be the case that the aging to pink is an effect of the R genotype
on W genotype tissue.

Lavatera x clementii 'Candy Floss' ('Cotton Candy' from some US
suppliers) has a colour pattern very similar to 'Rosea' (perhaps a
fraction paler), but has a herbaceous habit, and differently shaped
flowers. It seems to me that this is a similar cross, but with 'Rosea'
as the parent instead of 'Barnsley', and perhaps wild-type thuringiaca
rather than 'Ice Cool'.
--
Stewart Robert Hinsley