I love it when these wild flowers pop up unexpectedly in the yard. I believe they are rain lilies. Evidently, they grow from bulbs, but we've never planted any rain lily bulbs. I also see them here and there around the neighborhood in odd places. They seem to just spring up randomly in the middle of grassy areas.
I just read on tha interwebz that you can actually order bulbs for them, and that they're relatively easy to grow. Hmmm... maybe we should consider getting some and spreading them around like a smile.