Question: Explain Variegation in Ivy (vii): addendum

I verified my previous posts with Zonneveld's essay. It's fairly complete. There are only two bits of information I'd like to add to my finds. However, Zonneveld's essay covers more than the development of variegation. He also explains the causes of the possible changes a plant, leaf colour wise, can go through! I can't resist to post that explanation. But first the two additions.

When I explored the SAM, I stated that L1 contribute, in some plants, tissues around the leaf margin. Well, Hedera helix isn't one of them. For Hedera helix L2 is the layer that, besides the mesophyll, contribute the margin of the leaf. Zonneveld uses Hedera helix 'Goldheart' to explain yellow-centered variegation.

When I covered chimeras I listed the three types of chimera in plants. Zonneveld writes that sectional and mericlinal chimeras can lead to periclinal chimeras.

The next few posts will cover the causes of changes -and the possible changes- a variegated plant can go through.