I had pictured this a few months ago in a beautiful place named Baneshwar. My post named Crafted Leaf shows another beauty of Baneshwar.
This plant is considered a weed in India, spread almost all over the country. It's poisonous, but has medicinal use too. I remember my mother said once that this flower's juice, or the juice of its leaves, if applied in the eyes is useful for better vision. Please don't try it because it may need some preparation before applying. I'll have to ask my mom about this, and get important Ayurved information from her knowledge-pool :)