During the making of this film, Clint Eastwood directed his very first film, a behind the scenes look at his director Don Siegel at work called The Beguiled: The Storyteller (1971).
When McB is playing cards the deck has both the pictures (hearts, spades, etc) and the number in the corner. They didn't put #s on cards until 1864 and it was extremely rare to see a deck with them until 20-30 years after the war
In the opening scene (c. 3 minutes) the little girl doesn't actually pick the mushrooms, she just gathers up previously picked (and very clean) fungi by their cups. To pick a mushroom in the wild one must grasp it at the bottom of the stem or use a knife. Picking a mushroom by grasping the cup would break it in two.