There are 3 other red poppies which are very similar to the Common Poppy except for the shape
of their seed capsules:
   Long-headed Poppy (Papaver dubium), with elongated capsules
and petals without a dark blotch at the base;
   Prickly Poppy (Papaver argemone), with long bristly capsules;
   Rough Poppy (Papaver hybridum), with crimson flowers and bristly globular capsules