What plant is that?

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Photo credits: © Francis R. Underwood 2015

The mystery plant for December has a very unusual-looking flower and is often overlooked on a late spring walk through the woods.  It is a member of a family in which all the members have specialized flowers.  The flower on this plant has 3 sepals and 3 petals. The sepals are linear in shape, greenish-brown or purple-brown in color.  The two lateral petals which are about one-half the length of the sepals are yellow-green in color.  The third petal is the lip and its color is more or less a combination of the sepals and petals.  Each plant has 5 whorled leaves which are elliptical in shape and 1-2 inches long.  The stem bearing the leaves is 5-8” long.  The flowering stem is much shorter and 1 to 2” in length.  This plant can be found by carefully exploring in open, dry to moist, acid woods in May and June.

It’s. . .