Polar Supershroom

The polar supershroom split from its ancestor the boreal supershroom. It has moved to Darwin Rocky, Darwin Polar Scrub and Darwin Tundra where it was even colder than the boreal environment. It had to become more stout to conserve heat. Like its ancestor it grows bright red spore berries which attract frugivores with its bright color. The trunk and cap have no natural pigment and become whatever color it eats. In this case the brown decaying organic matter in the soil. They also have developed an antifreeze-like chemical in them to prevent them from freezing in the cold.