Yes ... and I think with "inter" (outward interaction between cells) he may be talking about how patterns may be made (eyes, etc.), for example, by color migrating between plant cells in different areas - the color of the throat or eye can show up to also color other parts of the petal, creating an edge or multiple-colors edges with the same colors. I saw some interesting pictures of this in "Distribution of colors in the Daylily flower." by Tom Hart at
http://www.hartsdaylilies.com/... (about half-way down the page).
Perhaps "intra" (inside interactions in a cell) is how different pigments in individual cells are expressed and may interact, like with the combination of Delphinidin and Cyanidin pigments creating colors of purple, violet or red, and maybe lycopene and beta-carotenes in the cell possibly making those colors appear muddy in some cultivars?
Edit: ayup, I think so ... he uses the inter (between) cell term again later, in talking about patterns, and intra (within) cell to talk about color expression (peeked again!).
