sleepy catchfly, Silene antirrhina

Sleepy because it sleeps through the day, and opens its flowers at night. Several plants in the genus follow that pattern, but this may be the most aggresively shy. You will rarely see an open bloom after sunrise, and if you do they will be at least as messy as this one.
Some plants don't produce petals at all. This is also really a catchfly. It has very sticky zones on the stem that do trap small bugs. Sleepy is considered protocarnivorous. It has developed chemicals that potentially can dissolve or absorb nutrients from the bugs, but it hasn't learned to use them yet. Sleepy is a weedy native that grows in every state and provinice except HI, LB, NF, NT, NU, and YT. Lenawee Co MI, 5/20/12.