Marigolds are seen in profusion on Day of the Day altars and graveyards. I snapped these at the Lake Chapala Society during a lull in the rain today.
http://ceenphotography.com/2015/10/31/flower-of-the-day-october-31-2015-halloween-flowers/
In Mexico, Dia de los Muertos is synonymous with marigolds, which are sold by the truckload! 
For more flowers, go here: http://ceenphotography.com/2015/09/16/flower-of-the-day-september-16-2015-inland-dynasty-dahlia/
In late October, everything in Mexico is about MARIGOLDS and Dia de Los Muertos!!!!
http://ceenphotography.com/2015/07/01/flower-of-the-day-july-1-2015-dahlias/
lifelessons - a blog by Judy Dykstra-Brown 