(Ignore the little Phyllanthus photo-bombing.)

Last pic. Blooms. Thanks for looking!

Hmm, it really looks like E. maculata, prostrate spurge. Could it be growing upwards because it's riding on other plants or reaching for the sun? I've found it poking up almost upright out of my closely-planted herb garden.

TY for your help. Part of it is hanging over the concrete sidewalk, but there is no other outside factor contributing to its' uprightness. Not obvious from these pics, sorry.

Thought that was the one with the red spot on each leaf? There are some of those around also in identical conditions, and less light, (assuming I'm attaching the right name to THOSE,) which are all flat as a pancake, right on the ground with much more definitely marked/variegated leaves. This one looks different in that it is growing primarily upright, and the placement of the flowers, very little marking on a few of the leaves.

Well, a look at my 'Weeds of the Northeast' took me to nodding spurge, Euphorbia nutans. Here's a link. From your descrption and the photos, it looks that's what you have.

Here is a link that might be useful: Euphorbia nutans

TY for the help! Those reddish seed balls would be something to look for soon to confirm.

I also think the size of the leaves clinches it. They look much larger than E. maculata in a comparison between your photos and my own extensive weed collection :-)

TY, I learned a new plant today.

Check out Chamaesyce nutans (Eyebane).

TY for the additional replies!

Jekeesl, that name seems to be one of many synonyms this plant is packing around, though no time left today to search through multiple databases to confirm the veracity of this Wiki info.

Chamaesyce is a synonym but has been deemed invalid since it is nested within Euphorbia.

Cool. I'll update my records.

TY, Lycopus! Sounds unanimous from a good number of serious plant-sters. Will put this name in my notes.

Thanks again for all of the replies!