I snapped these pictures while on a research trip this weekend in Port Aransas, Texas. This flower was spotted at our second study site right near the water. I put it on iNaturalist right away as “unknown” and began researching what kind of flower it might be. As I came to the conclusion that it was a Dayflower, someone had already identified it as a Dayflower ,or Commelina spp., on iNaturalist. I then identified it to species as Commelina erecta, or Widow’s Tears, and this id has been confirmed.
This perennial, also known as the Whitemouth Dayflower, is in the Spiderwort plant family. It is native to the US, and according to the IUCN Red List, it is of least concern. This plant usually only grows upright if it is supported by other plants; it typically grows along the ground and it can grow up to three feet long. The ephemeral flowers have two big blue petals and one small white petal. These flowers usually bloom from May to October. They bloom in clusters and a flower only blooms for one day, but there are other flowers on the plant that open three to four days apart.
Dayflowers like dry, sandy soils or muddy, clay soils and their habitats include open pinelands, dry scrub, woods, marshes, between rocks, streambanks, prairies, and along roadsides. Because of the broad habitats they can live in, these plants can become invasive. They are also a preferred food source of white-tailed deer.
My iNaturalist post can be found here.
Sources
http://www.wildflower.org/plants/result.php?id_plant=COER
http://www.iucnredlist.org/details/176972/0
https://plants.usda.gov/plantguide/pdf/pg_coer.pdf