Thanks so much, gardengal48. A poster in the Milkweed forum concurs: "Many Epilobiums are weedy, and not garden worthy, and if you let it go to seed, you will have an invasion."

I really don't need this invading what is already prime real estate among my milkweeds and zinnias. :)

To me this doesn't look like an Epilobium. The petals lack a notch. The 'whiskers' don't fit. It looks more like something in the Rubiaceae. Diodella seems a possibility but I don't know them so can't offer a species. How about D teres, aka Rough Buttonweed?

Rough Buttonweed looks like it, floral_uk; and it does appear to be prevalent in our area.

Coincidentally, in April I posted regarding a weed found in our St. Augustine lawn, and it was IDed as the dreaded Virginia buttonweed.

I've had quite the struggle, constantly pulling (as no herbicides work, apparently) in the hot weather we've had. After 48 hours of rain, I'm in denial and don't dare look in that area as I'm sure the VB has gone nuts.

After 26 years of home ownership and not experiencing any sort of buttonweed, I know have two varieties that the winds have blown in!

Thanks, everyone.

For sure Diodella teres, as floral suggested. That one used to be listed as Diodia teres.

I was the other person who identified it as Epilobium on the milkweed forum. It looks pretty much the same as many other plants on here that were i.d.'d as Epibolium.Good call floral. I'm not at all familiar with buttonweeds, and how did it get that common name. I don't see anything on the plant that resembles a button.

In the milkweed forum someone suggested this plant is Sherardia arvensis, but the leaves don't seem right for that. Are all the buttonweeds in the Diodia genus?

Jay, it isn't even close to Sherardia arvensis. That plant and Diodella are both in the Rubiaceae family, but the leaves are entirely different. The correct ID has already been provided.

Good morning -- I hope I don't need to take any more/different pics to settle this bet, as I've just yanked it (plus two smaller ones) from the bed. :) Seriously, thanks to everyone for taking time to post.

I was comepletly satisfied with floral's i.d. I was just curious, because I don't know much about these Rubiaceae species. I love the family, and my experience growing them just includes on a few members like Galium, Pentas, and Manettia, aka cleavers,Egyptian stars, and cany corn vine.

"It looks pretty much the same as many other plants on here that were i.d.'d as Epibolium." To my eye it really doesn't. Petal shape, flower form, apparently fused rather than separate petals, texture, buds at the leaf joints, those 'whiskers': the whole look of it didn't look right. I had a Rubiaceae feeling about it and I worked from there. I've never seen any Diodia or Diodella in person.