I'm stumped. As if overnight, clumps of stems came springing forth through the sedums in one of our rock gardens, near the pond. One cannot find leaves directly connected to any of these flowering clumps, but there are leaves nearby to each, springing out of the sedum. I can't tell if they belong to those flowers or not. The clumps of stems, each bearing one terminal flower, look all the world like dandelions. The stems are hollow, no noticeable sap from them. The dried seed heads also look like dandelions. Up each stem (and the stems are downwardly nodding) are small leaflets or bracts. During the day, they open up, but appear to close when the sun goes down as is shown in the pictures I took at dusk. I've never seen these growing on our property before, but given the profuse wind-borne seeds, shall likely never get rid of them. Here are two pictures and hoping someone can identify this wildflower/weed.

This post was edited by calliope on Tue, Apr 22, 14 at 20:49