Here is an old illustration from... maybe 2009? I am surprised I never put it up before because it is one of my favorites, Tashkent French Marigold:
I found this neat website today that's connected to the Royal Botanic Gardens all about plants and people, our cultures surrounding plants: http://www.kew.org/plant-cultures/index.html
And of course there is a lot on there about the marigold. Marigolds apparently originated in Central Mexico and were introduced to South Asia in the 16th Century. Now they are used as decorations and offerings for weddings, funerals, and all sorts of ceremonies.