Sheyal Kata(শিয়াল কাটা) is the local name of Argemone Mexicana in Bangladesh. This flower is a species of Poppy and used to be considered as mildly poisonous. It's easily understandable from the name that this flower is endemic to Mexico. But it is widely available around Africa, India, America now a days.
This is a flower having bright yellow petals(possibly six). The leafs have the sharp pointed thorn at the edge. The fruit is also covered with lot of thorns and hard to grab on bare hand. Some medical expert uses this plant to sooth the pain of kidney. I don't know how.
Mainly the white nectar(কষ) from the plant is poisonous, and can cause inflammation and might feel itchy. The seeds inside the fruits are almost similar to the mustard's seed(সরিষা বীজ). So people can easily mix these with mustard seeds(সরিষা বীজ). Since the seeds are poisonous, the extracted oil of contaminated mustard become poisonous too.
The photos for this article were captured from Dinajpur(দিনাজপুর) of Bangladesh. It was the May of 2010, I was traveling there. You can read more about Shiyal Kata(শিয়ালকাটা) plant and flower from Wikipedia
I have uploaded two of the photos from my recent Dinajpur tour(May 2012).