Miscalculated
I own nothing but my own Ideas
She smiled; luck was on her side today. Lover-boy was collecting food by himself.
Two -boy and Fire-girl were both much harder to steal from. Fire-girl was very forest savvy, and seemed used to watching over her food supplies. Two-boy had become very aware of his rapidly dwindling food supply, and had become hyper vigilant towards his remaining resources. Without his district partner he was very aware of what was left.
Lover-boy was reliant on fire-girl to ration it for him, but she wasn't here at the moment. Now would be the perfect time to grab some.
While she had always been good at memorising words, pictures had never been that useful to her. Even the best of pictures were worthless to her, for they never told one how the objects depicted in them smelt or tasted. Unfortunately for her, the majority of plants on the test had been pictures. She was unlikely to get killed from it, but it was always better to watch someone experienced, for that told the viewer what foods worked best, and sometimes led to methods that did not come up on the test.
Lover-boy had good instructions from fire-girl to follow, and was working steadily at his growing food pile. He appeared to be steadily absorbed in his work, so she took that as a cue to move closer. Quietly as she could, she moved slowly over the needles, hoping none would crack under her feet, until she was beside the pile.
She took a larger share then usual, but still not a significant amount in the pile. Today she got a little bit of everything. "Today is a feast" she told herself retreating. Once she was a safe distance away, she combined it with the food that came in her bag at the Cornucopia feast. She would need as much energy as she could get to survive to the end of the games. With only four tributes left, she would need all the energy she could muster to run away from the finally.
Because every finally needed something big and dramatic. Dangerous. All of the remaining tributes were better fed, and more physically powerful then her. If she were to have any hope at all, she would have to set up traps with the last of her supplies, and catch them in one. If fire girl were the last one standing in her way, she would have to run a path with many obstacles in, because the bow had serious range.
Deep in thought, she chewed on a root, and popped a dark berry into her mouth. Probably a blueberry from the colour. It tasted sweet. Usually it was the bitter berries that were poisonous.
She picked up a handful, only to drop them. Her stomach felt weird.
"Lover-boy is an idiot!" She realised abruptly. "I should have stuck with stealing directly from fire girl, these weren't on her list."
She tried to stand, but couldn't manage it, swaying and falling over, rather then getting to her feet. Her mouth felt dry, and she saw the forest around her, on fire. It was eating her, heat moving across her skin. She tried rolling, screaming, but she couldn't move.
She couldn't run, and that more then anything meant death.
I decided to try a "Foxface eats Nightlock by accident scenario." Once again I did not give her a name, but I also did not name Katniss, Peeta, or Cato by name. Instead they are Fire-girl, Lover-boy, and Career-boy. I figure if Katniss cant be bothered to learn her name (and Katniss is one of the few who view Foxface as a threat), then Foxface probably wouldn't take the time to learn theirs. After all, someone without a name is a lot easier to kill.
About the Poison
Symptoms of Poison often include loss of balance, blurred vision, headaches, dried mouth, constipation and hallucinations. I based the symptoms of nightlock off of nightshade or belladonna (as its more commonly called). Nightshade disrupts the parasympathetic nervous systems ability to regulate involuntary activities such as heart rate, sweating, and breathing. Since sweating serves to cool people down, I think Foxface hallucinating fire makes sense.
Nightlock was implied to work very fast, and given its similarities to Nightshade, I think It would be an evolved mutation. If she had eaten a handful of them, or the roots (the most potent part of a plant) her death would have come so fast she wouldn't have known what hit her.
Apparently, they look sort of like blueberries, and are sweet, but I don't see how they would be mistaken for wild blueberries, because wild blueberries are much smaller then store-bought, and lighter in colour.
The antidote to nightshade is Calabar bean, a poisonous plant that effects people with nerve gas symptoms. Apparently they cancel each others symptoms.