Frostrop
As the Saltrop spread southward, they had to adapt to the increasingly cold winters, which often killed the tropical species. As a result, the frostrop evolved in response to the darker and colder winters, eventually allowing it to survive in even the coldest of climates.
The frostrop has developed a range of defenses against cold weather. The first is its increased size, which allows it to trap more heat. It also will excrete brine, preventing ice crystals from forming in their cells. This also has the added benefit of deterring pathogens and parasites from entering its pores.
As the frostrop travelled further southwards, it had to survive increasingly dark winters. While the dark photosynthetic pigment allowed it to photosynthesize in darker conditions, it was not enough to allow it to continue spread southwards. As a result, some populations (most notably the polar ones) hibernate over the bulk of the winter. During the winter, these hibernating frostrops will live off of their starch reserves, which reside in spaces in between the vein network. The only notable behavior the frostrop engages in during hibernation is brine excretion.