It is a Tagetes but I believe that it is a subspecies is erecta. This Tagetes is endemic of Mexico and central america but has been introduced as a popular garden flower in USA and Canada.
This flower is very traditional in Mexico, The Aztecs gathered the wild plant as well as cultivating it for medicinal, ceremonial and decorative purposes.
Its flower, the cempasúchil is also called the Flower of the Dead in Mexico ("Flor de Muertos") and is used in the Día de los Muertos celebration every November 2nd. The word cempasúchil (also spelled cempazúchil) comes from the Nahuatl term for the flower zempoalxochitl, literally translated as "twenty flower". (extract taken from Wikipedia)
You can see the differences between the Tagetes Erecta and Tagetes Patula in the following links :
http://en.wikipedia.org/wiki/Tagetes_erecta
http://en.wikipedia.org/wiki/Tagetes_patula
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