Maysilee Donner was Madge Undersee's aunt and a tribute. She placed 5th out of 48 in her Games and allied with fellow District 12 tribute Haymitch Abernathy. She was the original owner of the mockingjay pin.
Maysilee Donner was one of the four tributes from District 12 in the 50th Hunger Games, along with Haymitch Abernathy, a second male, and second female tribute. The usual number of contestants from each district was two (one male and one female) but because the 50th Hunger Games was a Quarter Quell, the Capitol demanded that twice the number of tributes be reaped for the event. They chose this to remind the districts that for every Capitol citizen that was killed during the Dark Days, two rebels were also killed.
50th Hunger Games
During her time in the arena, Maysilee escaped from the Cornucopia with only a blowgun, a bowl, some dried beef, and a backpack of rope. She was very resourceful, dipping the blowgun darts into numerous amounts of poisons available in the arena and killing the other tributes including a career by shooting them with the poisoned darts.
When Haymitch was about to be killed by a Career Tribute by slicing his throat, Maysilee shot the Career with her poison blowgun. She arranged a temporary alliance with Haymitch, saying that they would last longer with the two of them, but broke it when they were among the final five tributes alive, as she didn't want to have to kill him.
Maysilee died only minutes after parting with Haymitch, being attacked by a large number of bright, candy-pink birds that used their sharp beaks to skewer her in the neck. Haymitch held her hand and stayed with her until she died.
25 years later, when Katniss Everdeen watched the video of the Quarter Quell, she compared this to when she held the District 11 tribute Rue as she died, which indicated Haymitch and Maysilee may have had a similar relationship to Katniss and Rue.
The mockingjay pin worn by Katniss since the 74th Hunger Games was originally Maysilee's and had been passed to her niece, Madge, who eventually gave it to Katniss as a tribute token. It later became a symbol for the second rebellion against the Capitol.
Maysilee was also the best friend of Mrs. Everdeen, Katniss's mother (as is mentioned in Catching Fire, when President Snow announces past Quarter Quells). When Katniss watches the video of the 2nd Quarter Quell, when Maysilee is reaped for the games, two girls with blond hair are seen clinging to her, and Peeta recognized that one of the girls was her mother.
Maysilee is said to have the traditional merchant look of smooth and straight blonde hair and blue eyes. She is also said to look a bit like Mrs. Everdeen but even more like Madge, her niece.
Maysilee was described to be quite resourceful, as she came up with the idea to dip her darts for her weapon, the blowgun, into the poisonous plants in the arena. She was also quite accurate with her blowgun, killing even a Career tribute.
Maysilee had a twin sister who later married Mayor Undersee who had a daughter, Madge. Before the Games, she lived with her parents, twin sister and possibly other siblings in a sweet shop in the merchant side of District 12.
Maysilee most likely didn't know Haymitch before the games, considering they lived in different parts of District 12. But she made an alliance with him and when she was fatally wounded he ran to her and held her hand as she died, indicating they must have cared for each other to some degree.
The wife of District 12's mayor, Mrs. Undersee (first name unknown), was Maysilee's twin sister. She struggled terribly after Maysilee died in the games, even after she was married and had a daughter, Madge. She suffered terrible headaches and was confined to bed, possibly suffering from depression. Because of how badly Mrs. Undersee was affected by Maysilee's death, it can be inferred that the sisters were very close.
In Catching Fire, Mrs. Everdeen reveals that she and Maysilee Donner were best friends. After Maysilee's death and the Games, Maysilee's mother gave Mrs. Everdeen her pet songbird to keep and care for. Mrs. Everdeen was also standing next to her when she was reaped, and broke down in tears along with Mrs. Undersee, her sister. Mrs. Everdeen had never mentioned Maysilee to Katniss, probably because she knew her children wouldn't like to know how she died.
Madge is Maysilee's niece. Maysilee's pin had been handed down to her and Madge has been mentioned wearing it. She gave it to Katniss after the reaping, proving their friendship, which was later used as the sign of the rebels during the second rebellion. Katniss doesn't find out the pin was Maysilee's until the events in Catching Fire, when she watches the video of Haymitch's Games. Madge is said to resemble Maysilee, with the same blonde hair and blue eyes.