mwdenslow's Identifications

Stellaria pallida (Lesser Chickweed or Apetalous Chickweed). NB: indicated with red arrows in photograph (NOT the adjacent blue-flowered Veronica arvensis!). Completely missed by me in this photograph initially but identified by iNaturalist botanist blue_celery who is familiar with Stellaria pallida in Europe. Lawns in front of Salt Marsh Nature Center, Marine Park, Brooklyn, NY.

Reproduced below are blue_celery's comments:

"the Stellaria growing next to Veronica arvensis is likely to be S. pallida. Note that the flowers below those of V. arvensis show the ovary that is not enlarged and the stigma is still fresh. Only the flower in the extreme right has already fruited and is going to disperse seeds.
S. pallida here is sometimes found growing together with S. media in the so-called Stellarietea mediae since they share the same habitat. Moreover it may be highly overlooked due to not-so-easily visible distinguishing characters and due to the frequent cleistogamy (in S. pallida flowers often do not open, self fertilize and then fruit).
Anyway, also sepals length and seeds size may be used as a useful characters since in S. pallida are slightly smaller and paler than in S. media.
Here it is S. pallida:
http://www.naturamediterraneo.com/forum/topic.asp?TOPIC_ID=246927
All Stellaria with well-developed petals are not S. pallida so the plant in your previous post are correctly identified as S. media."

I observed so many plants in Colorado this summer that I have not been able to ID. Hope someone knows them. Since this one was everywhere, surprised I cannot find it but maybe it is something invasive that no one wants.