They are commonly known as Fryer's Cowl or Larus. 

Found best in damp shaded areas, in the forest, or roadside.  They are an absolute delight to find and usually grow in large groups once a population has been established.  A single hooded flower growing on a spotted stem grows from an exquisitely veined leaf.  I can never decide if they look like they are sighing, singing, or sitting in perfect silence.