I suppose that having learned that there was not just "ground chillies" but Deggi Mirch, Kashmiri Mirch, and probably a few hundred other varieties as well, it should not have come as a shock to learn that there was more than one type of turmeric -- but there is !  A very interesting post by Ajoy Joshi, which focusses on a technique for retaining the bright green colour of spinach for up to a week after cooking.

** Phil.