In May of 1861 the Lincolns held a Strawberry Party in the first months of the Civil War and their life in the White House. The First Lady apparently wore this dress picturing the seasonal fruit to the event.
Mary Lincoln's dresses: Many of them were sold in a rather scandalous sale in New York shortly after the President was assassinated. While her physical and mental health declined she carried some in trunks in her wanderings for the rest of her life. As she always wore black mourning after Lincoln's death she had no need of them but she did love fashion.
The only other dress known to survive according to Dr. Cornelius is the one she wore to Ford's Theater on the night of the assassination but there are many supposed fragments of that garment.
The Chicago Historical Society has a plaid dress of Mary's seen here:
We'll stick with the Strawberry Dress story as one accurate account of a surviving dress.