Looks like Portulaca umbraticola AKA the other moss roses, ornamental purslane, & wingpod purslane - a reference to the wings on the seed pods, shown so clearly in your pic. The color could be from a nutrient issue, just a sporty, unusual individual, got chilled. Interested to hear others' thoughts about that too.

OK yes, so of the 3 primary Purslane species: Portulaca oleracea (Common Purslane), Portulaca umbraticola (Wingpod Purslane), and Portulaca grandiflora (Moss Rose) - this definitely seems to be Portulaca umbraticola due to its characteristic winged seedpods. Which refers to full, "winged" flanges around its seed cups, as opposed to simple, flat rims...

Maybe I can revisit this site later this year and look for some blooming flowers on them for further identification of variety. Because its leaf shape and color are just quite unusual!

The other question is that if Portulaca oleracea is clearly edible, but Portulaca grandiflora is not (based upon oxalic acid contents) - what about Portulaca umbraticola? How does its oxalic acid content compare to that of the others???

Yes, Every time I put pics of my cute little P. umbraticola blooms in FB groups, people from other countries make comments as if it is *the* edible purslane. After being sold as P. oleracea for decades, if there was a noticeable difference in regard to edibility, I don't think that confusion would have persisted to this day.

^ Yes, there's understandably a LOT of confusion between Portulaca oleracea and Portulaca umbraticola! I'd still like to see some actual quantitative metrics on the oxalic acid content of Portulaca umbraticola, though.

Incidentally, I just revisited that field that had been covered in this red Wingpod Purslane last Fall. Well, it is now covered in Bitterweed, without a single Purslane plant to be found...

So, again, even in this case, Purslane only dominated this field for a few short growing months, before it died off until next season. It's important to note that even when Nature doesn't space different species out in space, it may sometimes in TIME (natural crop rotation).

I guess I'll keep an eye out more in the early Fall timeframe, then...