It is Aarne-Thompson type 709, Snow White, though substituting many motifs: sisters for the stepmother, the Sun for the magic mirror, abandonment in the woods for an attempt to kill, and the Months for dwarves. Others of this type include Bella Venezia, Nourie Hadig, and Gold-Tree and Silver-Tree.
Myrsina is the youngest of three orphaned sisters. Three times, the sun declares that she is the most beautiful. Her jealous sisters tell her it is time to honor their mother with a memorial, or to rebury her. They make the traditional food, go to her grave in the forest, and exclaim they have forgotten the shovel and so can not plant flowers, or can not dig her up to rebury her. The two oldest must go back for it, and Myrsina watch the food. In the evening, Myrsina realizes they will not return and cries. This wakes the trees, and one tells her to roll her bread down the hill and follow it. She does and lands it a pit, but the pit holds a house. She hides there and does the housework while the owners, the Months, are about. The Months wonder who is doing it until the youngest stays behind and hides. He catches her, and the Months take her as their sister.
Word reaches her sisters. They come to her with a poisoned cake, claiming to have been unable to find her. She gives part of the cake to the dog, and it dies. When the sisters hear she is still alive, they come back; she will not open the door to them, but they claim to have a ring that their mother said must go to Myrsina. She could not defy her mother's wishes and put on the ring. She fell to the floor. The Months returned, lamented her, and kept her body in a golden chest.
A prince came by, and they gave him their best room, so that he saw the chest. He pled for it, and they finally gave it to him, on the condition that he never open it. He became ill and did not want to die without knowing was in the chest. He opened it, wondered at Myrsina, and thought the ring might tell her who she was. He took it off, and Myrsina came back to life. Myrsina had the ring thrown into the sea and married the prince. One day, her sisters came to harm her, and the prince had his soldiers deal with them.