This little orchid, Helleborine orchid, that I thought was native , is actually an introduction from Europe. It likes to grow in the shadier areas of our lawn and garden, or pop up in a flower bed. It is a perennial and in some parts of the US is considered invasive, but it certainly is not aggressive where we are in Ontario.
It's an easy plant to miss because this is what it looks like from above - not very exciting with dull brownish flowers.
But look at the underside, and you'll find quite a fancy flower.