Last year I noticed a small stand of pointed-leaf tick trefoil (Desmodium glutinosum) among the lopseed stand along lower Cabin John Creek (a tributary of the Potomac).  The leaf is distinctive:

What I didn’t see was the flowers.  When I went back a week or so later, there weren’t any flowers, but there were a few loments* dangling, tormenting me.

This year when I went to photograph the lopseed, I saw the pointed-leaf tick trefoil again, and a single flower, damaged by rain and barely recognizable.  So I gave it a few days and went back.  Nothing.  No buds, no flowers, no loments.

I was amused, though, to read that both lopseed and pointed-leaf tick trefoil often grow and bloom together.

At any rate, here’s a picture of a single blossom of naked-flowered tick trefoil, a different species (Desmodium nudiflorum), but the flowers are almost identical.

* a characteristic fruit of some plants in the Fabaceae