Jack-in-the-Pulpit bloom

The curious bloom of Jack-in-the-Pulpit, Arisaema triphyllum, is typically a green raspberry-like structure, or corm, shrouded in a curling, purple hood, and the fanciful resemblance to a monk (or cleric with a high collar) lends the plant its name. In summer the corm of this Illinois woodland native turns bright red.
 
For more about Jack-in-the-Pulpit and native plants for the Midwest, especially those that do well in shade/moist areas, see the "book" on this website, Gardening with Native Plants in Shady Evanston.